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Acute Toxicity

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Butler, Philip A. 1961. Effects of Pesticides on Commercial Fisheries. In: Proc. Gulf Caribb. Fish. Inst., 13th Annual Session, Nov., 1960. James B. Higman, Editor. University of Miami, Gulf and Caribbean Institute, Coral Gables, FL. Pp. 168-171. (ERL,GB 026).

Both the Milford and Gulf Breeze workers have noted that the first evidence of toxicity of pesticides to shellfish is a decrease in growth rates. It is reasonable to suggest that our ability to evaluate this item may eliminate much costly and time-consuming work in the future. We are interested not only in the pollution levels causing acute toxicity and death, but also those causing more subtle reactions which over a period of time may affect reproductive potential and longevity. Using the growth of small oysters as a criterion of pesticide toxicity, we find two points of particular interest. After the lowest concentration of a chemical that causes a decrease in growth has been determined, we find that exposure to a further ten-fold dilution produces no apparent ill effects, even over a period of several weeks. Secondly, when adversely affected oysters are returned to clean sea water, the normal growth rate is reinstated within a short period of time, usually a few days. We may hope that so far as oysters are concerned, and perhaps other estuarine forms, that not only are subacute toxicities transitory but that they may be avoided by relatively small increases in the dilution factor. It is possible that under natural conditions and barring accidents, average dilution factors are so great that these chemicals pose no real threat to estuarine and marine forms. These items are not suggested to lull us into any feeling of security with regard to chemical pollution but rather to point out how a coordinated and productive research program can provide the basis for better resource management. Agricultural chemicals are here to stay. With sufficient knowledge of their immediate and residual effects, it will be possible for us to utilize them to the fullest extent and with minimum damage to our valuable natural resources both on land and in the sea.

Lowe, Jack I. 1964. Effects of Pesticides on Estuarine Animals. In: Proc. of the First Gulf Conference on Mosquito Suppression and Wildlife Management, Nov. 16-18, 1964, Lafayette, LA. National Mosquito Control Fish and Wildlife Management Coordination Committee. Pp. 83-86. (ERL,GB 051).

At the present time the Bureau of Commercial Fisheries is conducting a research program to determine the effects of pesticides on commercial fishery resources. I should like to discuss certain phases of this research and their relation to field applications of pesticidal chemicals. The value of the estuarine environment to commercial fishery resources can not be over emphasized. Our most important commercial species of finfish and shellfish spend all or part of their life span in estuarine waters. Sessile or slightly motile forms as oysters and clams are necessarily restricted to these inshore waters. Motile species such as crabs, shrimp, menhaden and mullet spend much of their early life in lower salinity waters near sources of natural land drainage. Heavy spraying of certain chemicals to control larvae in or near estuarine waters can be very destructive to these marine forms both through direct kills and destruction of their food supply. However, the amount of insecticides used in such coastal operations is far outweighed by that used on forest and farmlands. It seems inevitable that some of these chemicals or their metabolites will reach estuarine waters. One of the major objectives of our research program has been the determination of acute toxicity of the commonly used pesticides to representative marine species. These bioassays are conducted under controlled laboratory conditions. The development of uniform testing methods has been an important part of this research. Since several phyla of marine organisms are used as bioassay animals, different criteria of toxicity must be used. Each chemical is tested on oysters, shrimp, phytoplankton and at least one species of marine fish.

Lowe, Jack I. 1967. Effects of Prolonged Exposure to Sevin on an Estuarine Fish, Leiostomus xanthurus Lacepede. Bull. Environ. Contam. Toxicol. 2(3):147-155. (ERL,GB 077).

Sevin® is the registered trademark of the synthetic carbamate insecticide, 1-naphthyl N-methylcarbamate. It is also known as carbaryl. This insecticide is toxic to a wide variety of insects as both a contact and a stomach poison. It is reported to be effective against many insects which have become resistant to chlorinated hydrocarbon and phosphate insecticides. Sevin® is also toxic to crustaceans and has been used to a limited extent in marine environments to control burrowing shrimp, Callianassa californiensis and Upogebia pugettensis. The digging activities of these crustaceans make the substrate in some areas unsuitable for oyster production. Sevin® has a relatively low degree of mammalian toxicity and is generally classified among the safer pesticides now in use. This comparatively low acute toxicity also applies to fish. The amount of Sevin® required to produce a 48-hr. LC50 (concentration lethal to 50% of test population) in rainbow trout, Salmo gairdneri, and longnose killifish, Fundulus similis, is about 250 times greater than that of DDT. Katz tested 95% Sevin® and reported the 48-hr. TLm (median tolerance limit) for coho salmon (Oncorhynchus kisutch), rainbow trout, bluegill, (Lepomis macrochirus), and threespine stickleback (Gasterosteus aculeatus) to be 0.99, 1.35, 5.30, and 10.45 p.p.m., respectively. Stewart, Millemann, and Breese reported 80% Sevin® to give a 24-hr. TLm of 6.7 p.p.m., for the threespine stickleback. They also found 1-naphthol, a hydrolytic product of Sevin, to be more toxic than Sevin® to fish. In the present study juvenile spot, Leiostomus xanthurus, survived 5 months of continuous exposure to 0.1 p.p.m. Sevin® in flowing sea water. I am unaware of previous studies in which marine fish were chronically exposed to Sevin® or other carbamate insecticides.

Lewis, Michael A., Carol B. Daniels, James C. Moore and Thomas Chen. 2002. Potential Genotoxicity of Wastewater-Contaminated Pore Waters with Comparison to Sediment Toxicity and Macrobenthic Community Composition. EPA/600/J-02/324. Environ. Toxicol. 17:63-73. (ERL,GB 1046).

The objectives of this survey were to determine the genotoxic potential of sediment pore waters above and below 10 wastewater outfalls and to compare the results to sediment chemical quality guidelines, acute toxicity, and macrobenthic community composition. The focus of the study was on genotoxicity since its occurrence in environmental media below wastewater discharges in the Gulf of Mexico region has not been reported in the scientific literature. Pore waters from 43 sediment samples were assayed using a microbial mutagenicity assay before and after activation with a rat liver microsome mix (S-9). A combination of either direct or activated responses was observed for 40% of the pore waters. Direct, activated, and both direct and activated responses were observed in 5, 26, and 9% of the total samples, respectively. Mutagenic effects were observed below 7 of the 10 outfall areas and in 4 of 6 control areas associated with 6 outfalls. The lowest pore water concentrations causing an activated mutagenic response were statistically similar above and below the outfalls. Mutagenicity occurred more frequently than acute toxicity to estuarine and freshwater invertebrates and there was no consistent relationship between its occurrence and the exceedance of sediment chemical quality guidelines. In contrast, there was some indication that mutagenic activity paralleled low benthic community diversity.

Lewis, M.A., D.E. Weber and R.S. Stanley. 2000. Wetland Plant Seedlings as Indicators of Near-Coastal Sediment Quality: Interspecific Variation. EPA/600/J-00/. Mar. Environ. Res. 50(1-5):535-540. (ERL,GB 1068). (PRIMO 10)

The toxicities of whole sediments collected from an urbanized Florida bayou-estuary were determined for the epibenthic mysid, Mysidopsis bahia, and the infaunal amphipod, Ampelisca abdita. In addition, the phytotoxicities of the same sediments were evaluated using rooted macrophytes, Scirpus robustus Pursh and Spartina alterniflora Loisel. The results of the 24 bioassays conducted for 7-28 days, were compared for interspecific differences. Toxicity to the benthic invertebrate species was predicted to be likely in all cases, based on comparison to effects-based sediment quality assessment guidelines. However, acute toxicity was uncommon and occurred at only one of the six sampling stations. In contrast, several sediments were either significantly phytostimulatory or phytoinhibitory (P<0.05) relative to a reference estuarine sediment. The results show the importance of considering interspecific variation and phytoassessment in contaminated sediment evaluations. Phytoassessment, the focus of this research, provided useful information that would have been missing if only the animal test species were used. For this reason, the phytotoxicity data base needs to be increased to better evaluate the relevance of most current contaminated sediment evaluations for coastal areas and also to determine the realism of proposed numerical sediment quality assessment guidelines and criteria.

Lewis, Michael A. and Steven S. Foss. 2000. Caridean Grass Shrimp (Palaemonetes pugio Holthius) as an Indicator of Sediment Quality in Florida Coastal Areas Affected by Point and Non-Point Source Contamination. Environ. Toxicol. 15(3):234-242. (ERL,GB 1069).

Grass shrimp are one of the more widely distributed estuarine benthic organisms along the Gulf of Mexico and Atlantic coasts, but they were used infrequently in contaminated sediment assessments. Early-life stages of caridean grass shrimp, Palaemonetes pugio (Holthuis), were used in this baseline survey as indicators of sediment pore water quality for several Florida coastal areas affected by nonpoint and point sources of contamination. Static toxicity tests were conducted using 24 well culture plates assessing embryo and larval survival after 12 days exposure to pore water (interstitial water). Acute toxicity was observed in 28% of pore waters (15 of 53 samples) suggesting that sediment contamination was not widespread in the study area based on the response of this species. When toxicity was observed, grass shrimp pore water toxicity test was usually a more sensitive indicator of contamination than solid-phase tests conducted with the epibenthic invertebrate, Mysidopsis bahia. P. pugio embryos were more sensitive than larval form and response of different brood stocks were similar (P>0.05) when exposed to same pore waters. Based on all considerations, this early-life stage toxicity test shows promise being useful detecting pore water toxicity. This conclusion is based on availability of a test methodology which requires minimal space and effort, and the test species widespread geographical distribution. However, there are several remaining research needs, including the important issues of its sensitivity relative to that for other pore water test species as well as for species used in solid-phase toxicity tests.

Parrish, Patrick R., John A. Couch, Jerrold Forester, James M. Patrick, Jr. and Gary H. Cook. 1974. Dieldrin: Effects on Several Estuarine Organisms. In: Proc. 27th Annu. Conf. Southeast. Assoc. Game Fish Comm. Pp. 427-434. (ERL,GB 178).

Tests were conducted to determine (1) the acute toxicity of dieldrin in flowing sea water to American oysters (Crassostrea virginica), pink shrimp (Penaeus duorarum), grass shrimp (Palaemonetes pugio) and sheepshead minnows (Cyprinodon variegatus) and (2) the rate of dieldrin uptake and depuration by spot (Leiostomus xanthurus). Acute (96-hour) EC50's were: oysters, 12.5 µg/l; pink shrimp, 0.9 µg/l; grass shrimp, 11.4 µg/l; and sheepshead minnows 23.6 µg/ l. Spot exposed to 0.0135, 0.075, 0.135, 0.75 or 1.35 µg/l for 35 days accumulated the chemical with maximum concentrations attained in 11 to 18 days. Maximum whole-body residue (wet-weight) was 6,000 X the concentration in test water. Spot contained no detectable dieldrin residues at the end of a 13-day depuration period in dieldrin-free water. Tissue alterations, such as subepithelial edema in gill lamellae and severe lysis and sloughing of the small intestine epithelium, occurred in spot exposed to 1.35 µg/l for four days.

Schimmel, Steven C., Richard L. Garnas, James M. Patrick, Jr. and James C. Moore. 1983. Acute Toxicity, Bioconcentration, and Persistence of AC 222,705, Benthiocarb, Chlorpyrifos, Fenvalerate, Methyl Parathion, and Permethrin in the Estuarine Environment. EPA-600/J-82-030. J. Agric. Food Chem. 31(1):104-113. (ERL,GB 186). (Avail. from NTIS, Springfield, VA: PB83-191239)

Six pesticides were evaluated in laboratory studies to determine acute (96-h) toxicity, octanol-water partition coefficients (log P), solubility, and persistence in seawater. In addition, three of the six pesticides (synthetic pyrethroids) were tested using the eastern oyster (Crassostrea virginica) in long-term (28-day) tests to determine their respective bioconcentration factors (BCF). Acute toxicity tests provided the following decreasing order of toxicity to estuarine crustaceans and fishes: AC 222,705, fenvalerate, permethrin, chlorpyrifos, methyl parathion, and benthiocarb. The estuarine mysid (Mysidopsis bahia) was consistently the most sensitive species, with LC50 values as low as 0.008 µg/L. The sheepshead minnow (Cyprinodon variegatus) was generally the least sensitive (range of LC50 values = 1.1-1370 µg/L). log P values were inversely related to solubility in seawater. The following are the increasing order of log P values (range, 1.8-6.5) and decreasing order of solubility (range >1000-24 µg/L): methyl parathion, benthiocarb, chlorpyrifos, AC 222,705, fenvalerate, and permethrin. Pesticide half-lives in sediment-water studies ranged from 1.2 to 34 days and were in the following order of increasing persistence: methyl parathion, permethrin, benthiocarb, AC 222,705, chlorpyrifos, and fenvalerate. The steady-state BCF's of the three synthetic pyrethroids were 1900 for permethrin, 2300 for AC 222,705 and 4700 for fenvalerate. After termination of the exposure, each insecticide was depurated by oysters to nondetectable concentrations within one week.

Lewis, Michael A., Steven S. Foss, Peggy S. Harris, Roman S. Stanley and James C. Moore. 2001. Sediment Chemical Contamination and Toxicity Associated with a Coastal Golf Course Complex. Environ. Toxicol. Chem. 20(7):1390-1398. (ERL,GB 1099).

The increasing density of golf courses represents a potential source of sediment contamination to nearby coastal areas, the chemical and biological magnitude of which is almost unknown. The objective of this study was to determine the concentrations of contaminants and toxicities of sediments impacted by a coastal golf course complex. Sediment contaminant concentrations were determined at least twice during the two-year study period at 14 sampling stations. In addition, a combination of acute and chronic bioassays were conducted exposing four invertebrate test species to whole sediments and associated pore waters. Overall, the Florida, USA, golf course complex had a measurable impact on sediment chemical quality, particularly in near-field areas. Higher concentrations of several trace metals and organochlorine pesticides were detected in many golf course-associated sediments compared to reference areas; however, concentrations decreased seaward and only a few, primarily chlorinated pesticides, exceeded proposed sediment quality guidelines. Chromium, zinc and mercury were detected more frequently than other trace metals. The DDT and associated metabolites, dieldrin and chlordane were the more commonly detected organic contaminants. Acute toxicity was uncommon and occurred consistently for sediment collected from one coastal location. In contrast, chronic toxicity occurred at several study sites based on the response of Mysidopsis bahia. It was concluded that the impact of golf course runoff on sediment quality may be subtle and sensitive biological assessment methods, such as chronic toxicity tests, will be needed to determine adverse effects.

Butts, Glenn L. and Michael A. Lewis. 2002. Survey of Chemical and Biological Structure in Three Florida Bayou-Estuaries. EPA/600/J-00/430. Gulf Mex. Sci. 20(1):1-11. (ERL,GB 1110).

Detailed information on the benthic macroinvertebrate community composition is unavailable for most Gulf of Mexico near-coastal areas. In response, structural and functional characteristics of this biota were determined, in conjunction with sediment chemical quality and acute toxicity, for three urbanized bayous. Sediment chemical contamination the bayous was common. Numerical sediment quality assessment guidelines were exceeded at 13 of the 16 sampling stations for as many as six analytes. However, the results of whole sediment toxicity tests conducted with the benthic invertebrates Mysidopsis bahia (epifaunal) and Ampelisca abdita (infaunal) indicated that 14 of the 16 sediments were not acutely toxic. The benthic macroinvertebrate composition was indicative of that for organically enriched sediments and the quality was spatially distinct and sometimes increased seaward. The percent of the fauna indicative of organic enrichment ranged from 14 to 100% for the 16 sampling stations. Pollution-tolerant infaunal species such as the polychaetous annelids Streblospio benedicti and Mediomastus ambiseta were dominant. The Shannon-Weiner diversity index value ranged from 1.0 to 3.8. The quality of the macroinvertebrate communities paralleled the results for sediment chemical quality and particle size distribution more so than those for acute toxicity. It was obvious that an integrated chemical and biological assessment was needed to characterize the environmental condition of the sediments in these urbanized coastal habitats.

Sappington, Linda C., Foster L. Mayer, F. James Dwyer, Denny R. Buckler, John R. Jones and Mark R. Ellersieck. 2001. Contaminant Sensitivity of Threatened and Endangered Fishes to Standard Surrogate Species. Environ. Toxicol. Chem. 20(12):2869-2876. (ERL,GB 1117).

Standard environmental assessment procedures are designed to protect terrestrial and aquatic species. However, it is not known if endangered species are adequately protected by these procedures. At present, toxicological data obtained from studies with surrogate test fishes are assumed to be applicable to endangered fish species, but this assumption has not been validated. Static acute toxicity tests were used to compare the sensitivity of rainbow trout, fathead minnows, and sheepshead minnows to several federally listed fishes (Apache trout, Lahontan cutthroat trout, greenback cutthroat trout, bonytail chub, Colorado pikeminnow, razorback sucker, Leon Springs pupfish, and desert pupfish). Chemicals tested included carbaryl, copper, 4-nonylphenol, pentachlorophenol, and permethrin. Results indicated that the surrogates and listed species were of similar sensitivity. In two cases, a listed species had a 96-h LC50 (lethal concentration to 50% of the population) that was less than one half of its corresponding surrogate. In all other cases, differences between listed and surrogate species were less than twofold. A safety factor of two would provide a conservative estimate for listed cold-water, warm-water, and euryhaline fish species.

Mayer, Foster L., Mark R. Ellersieck, Gary F. Krause, Kai Sun, Gunhee Lee and Denny R. Buckler. 2002. Time-Concentration-Effect Models in Predicting Chronic Toxicity from Acute Toxicity Data. In: Risk Assessment with Time to Event Models. Mark Crane, Michael C. Newman, Peter F. Chapman, and John Fenlon, Editors. Lewis Publishers, Boca Raton, FL. Pp. 39-67. (ERL,GB 1126).

Methods for modeling aquatic toxicity data based on linear regression, multifactor probit analysis, and accelerated life testing were developed in which simultaneous consideration is given to concentration, degree of response, and time course of effect. A consistent endpoint (lethality) and degree of response were used. These methods predict chronic toxicity from acute toxicity data. The methods were validated against results of chronic toxicity tests. When the techniques were applied to a data base of 18 chemicals and 7 species of fish, predicted chronic no-effect concentrations were highly accurate greater than 85% of the time. Limitations of the methods are presented.

Dwyer, F. James, Foster L. Mayer, Denny R. Buckler, Christine M. Bridges, I. Eugene Greer, Douglas K. Hardesty, Christopher E. Henke, Christopher G. Ingersoll, James L. Kunz, Linda C. Sappington, David W. Whites, Tom Augspurger, David R. Mount, Kathy Hattala and Gary Neuderfer. 2005. Assessing Contaminant Sensitivity of Endangered and Threatened Aquatic Species: Part I. Acute Toxicity of Five Chemicals. Arch. Environ. Contam. Toxicol. 48(2):143-154. (ERL,GB 1180).

Assessment of contaminant impacts to endangered and threatened (listed) species requires understanding of a species' sensitivity to particular chemicals. The most direct approach would be to determine the sensitivity of a listed species to a particular contaminant or perturbation. An indirect approach for aquatic species would be application of toxicity data obtained from standard test procedures and surrogate organisms typically used in laboratory toxicity tests. Standard surrogate test species (fathead minnow, Pimephales promelas; sheepshead minnow, Cyprinodon variegatus; rainbow trout, Oncorhynchus mykiss) and 17 listed or closely related species were tested with 5 chemicals (carbaryl, copper, 4-nonylphenol, pentachlorphenol, permethrin) representing a broad range of toxic modes of action. No single species was the most sensitive to all chemicals. For the three standard surrogate test species evaluated, the rainbow trout was more sensitive than either the fathead minnow or sheepshead minnow, and was equal to or more sensitive than listed species 81% of the time. To estimate an LC50 for a listed species, a factor of 0.63 can be applied to the geometric mean LC50 of rainbow trout toxicity data, and more conservative factors can be determined using variance estimates (0.46 based on 1 standard deviation (SD) of the mean and 0.33 based on 2 SD of the mean). Regardless of the factor used, the estimates are less of an adjustment than division by a safety factor of 10. Additionally, for the listed species tested, a low-or no-acute effect concentration can be estimated by multiplying their respective LC50 by a factor of about 0.56 which supports the USEPA approach of multiplying the final acute value by 0.5 (division by two). When captive or locally-abundant populations of listed fish are available, consideration should be given to direct testing. When direct testing cannot be performed, approaches for developing protective measures using surrogate species toxicity data are available.

Lewis, Michael A., Carol B. Daniels and Cynthia A. Chancy. 2006. Microbial Genotoxicity as an Environmental Indicator for Near-Coastal Sediment Pore Waters. Environ. Toxicol. 21(3):193-204. (ERL,GB 1195).

The genotoxic potential of environmental media collected from coastal areas impacted by anthropogenic contaminants has not been reported frequently in the scientific literature, particularly in the Gulf of Mexico region. This report summarizes the microbial mutagenicity of 31 pore waters obtained from surficial sediments impacted by non-point source runoff and compares the results to more traditional chemical and biological measures of sediment quality. Pore waters were extracted by centrifugation from sediments collected adjacent to a Florida coastal golf complex and from those in a nearby urbanized bayou-estuary. Genotoxicity was determined using a commercially-available short-term screening assay. Sediments and associated pore waters were analyzed also for acute toxicity to either Hyallela azteca, Palaemonetes pugio or Mysidopsis bahia and benthic macroinvertebrate diversity. Genotoxic activity (direct and enzyme-activated) was detected in 4 of 17 pore waters (golf complex) and 10 of 14 pore waters (urbanized bayou). The lowest detectable effect pore water concentrations were between 1.8 and 44.4% (direct) and 2.6 and 25% (enzyme-activated). The results of the genotoxic assay paralleled those based on exceedances of proposed sediment quality guidelines and pore toxicity to P. pugio in 81% and 58% of the comparisons, respectively. Shannon-Wiener diversity index values were significantly less in sediments containing genotoxic pore waters.

Lewis, Michael A. 2005. Sediment Habitat Assessment for Targeted Near-Coastal Areas. In: Estuarine Indicators. Stephen A. Bortone, Editor. CRC Press, Boca Raton, FL. Pp. 79-98. (ERL,GB 1201).

Sediment chemical and biological quality is summarized for 97 targeted sites in the Gulf of Mexico, most of which are affected by point and non-point contaminant sources. Chemical contamination and adverse biological effects occurred more frequently in estuarine areas receiving treated wastewaters and urban stormwater runoff. Contaminant concentrations in 51% and 84% of the sediments were less than TEL and PEL sediment quality guidelines proposed for Florida coastal areas, respectively. The guidelines were exceeded for 16 (>TEL) and 11 (>PEL) analytes. Total individual exceedances at each site were usually 3 or less (79% of sediments). Exceedances (>TEL less than or equal to PEL) were more common for copper, cadmium and DDE; and lead, zinc and DDD (>PEL). Concentrations of cadmium, copper, chromium, lead and zinc were above background levels more frequently in sediments collected from areas affected by urban stormwater runoff and treated wastewater discharges. Results for acute and chronic toxicity (benthic invertebrates), genotoxicity (microbial) and phytotoxicity (rooted vascular plants) showed varied biological responses and different measures of sensitivity. Acute toxicity to at least one of six test species was observed in 8% of the toxicity tests. Chronic toxicity to benthic invertebrates, microbial genotoxicity and phytotoxicity were observed in 33%, 54% and 57% of the corresponding toxicity tests, respectively. Benthic diversity was classified as poor for 61% of the sediments (Shannon-Wiener diversity index values <2.0). The biological and chemical results were concordant for 50% to 60% of the sediments. Increase utilization of chronic toxicity tests, the need for reference biocriteria and the identification of cause(s) of impairment are needed to increase the relevancy of sediment hazard assessments and to ensure successful management of this important habitat.

Buckler, Denny R., Foster L. Mayer, Mark R. Ellersieck and Amha Asfaw. 2005. Acute Toxicity Value Extrapolation with Fish and Aquatic Invertebrates. Arch. Environ. Contam. Toxicol. 49(4):546-558. (ERL,GB 1235).

Raimondo, Sandy, Brian J. Montague and Mace G. Barron. 2007. Determinants of Variability in Acute to Chronic Toxicity Ratios in Aquatic Invertebrates and Fish. Environ. Toxicol. Chem. 26(9):2019-2023. (ERL,GB 1287).

Variability in acute to chronic ratios (ACRs; LC5O/chronic value) has been a continuing interest in aquatic toxicology because of the reliance on ACRs to estimate chronic toxicity for chemicals and species with known acute toxicity but limited or no information on sublethal toxicity. To investigate variability and significant differences in ACRs, an extensive dataset was compiled of 503 same-species pairs of acute and maximum accepted toxicant concentration values for metals, narcotics, pesticides, and other organic chemicals. The overall median value of the aquatic invertebrate and fish ACRs analyzed in this study was 8, with a 140,000-fold range (0.13 to 18550) in values, and a 38-fold range (2.1 to 79.5) in 10th and 90th percentile values. Median ACRs for taxa, ambient habitat media, test type, endpoint, and chemical MOA/class categories were generally similar, but in some cases extremely variable (ranges of <1 to >10,000). There were no significant differences in median ACRs between taxa, although invertebrates were more variable than fish. Freshwater organisms had median ACRs significantly greater than saltwater species and were more variable. There were no significant differences in median ACRs among chemical MOA/class datasets, however ACR variance differed significantly among MOAs. Although few significant differences occurred among median ACRs for different groups, those categories that were highly variable are at an increased risk of underestimated chronic toxicity when mean or median ACRs are used.

Raimondo, Sandy, Deborah N. Vivian and Mace G. Barron. 2007. Web-based Interspecies Correlation Estimation (Web-ICE) for Acute Toxicity: User Manual Version 1.1. EPA Center for Exposure Assessment Modeling (CEAM) http://www.epa.gov/ceampubl/fchain/webice/iceManual.htm. 21p. (ERL,GB 1292).

Predictive toxicological models are integral to environmental risk assessment where data for most species are limited. Web-based Interspecies Correlation Estimation (Web-ICE) models are least square regressions that predict acute toxicity (LC5O/LD5O) of a chemical to a species, genus, or family based on estimates of relative sensitivity between the species of interest and that of a surrogate species. Web-ICE includes a total of _______ models for aquatic and 828 models for wildlife taxa. Overall for wildlife species, Web-ICE predicts toxicity within 5-fold of the actual value with 85% certainty and within 10-fold of the actual value with 95% certainty. Models are most accurate for species within a genus and family, with increasing uncertainty with greater taxonomic distance.

Awkerman, Jill, Sandy Raimondo and Mace Barron. 2008. Development of Species Sensitivity Distributions for Wildlife Using Interspecies Toxicity Correlation Models. Environ. Sci. Technol. 42(9):3447-3452. (ERL,GB 1316).

Species sensitivity distributions (SSD) are cumulative distributions of chemical toxicity of multiple species and have had limited application in wildlife risk assessment because of relatively small datasets of wildlife toxicity values. Interspecies correlation estimation (ICE) models predict the acute toxicity to untested taxa from known toxicity of a single surrogate species and were used to predict toxicity values and generate wildlife SSDs for 23 chemicals using four avian surrogates. The hazard levels associated with the fifth percentile of the distribution (HD5) were compared for ICE SSDs and independent SSDs created with measured data. SSDs were composed of either avian only or avian and mammalian taxa. ICE HD5s were within 5-fold of 90% of measured HD5s. Using a bird surrogate to predict toxicity to birds and the Norway rat to predict toxicity to mammals improved some estimates of ICE HD5s compared with those generated using only bird surrogates. These results indicate that ICE models can be used to generate SSDs comparable to those derived from measured wildlife toxicity data and provide robust estimates of the HD5.

Dyer, Scott D., Donald J. Versteeg, Scott E. Belanger, Joel G. Chaney, Sandy Raimondo and Mace G. Barron. 2008. Comparison of Species Sensitivity Distributions Derived from Interspecies Correlation Models to Distributions Used to Derive Water Quality Criteria. Environ. Sci. Technol. 42(8):3076-3083. (ERL,GB 1317).

Species sensitivity distributions (SSD) require a large number of measured toxicity values to define a chemical’s toxicity to multiple species. This investigation comprehensively evaluated the accuracy of SSDs generated from toxicity values predicted from interspecies correlation estimation (ICE) models. ICE models are log-log correlations of multiple chemical toxicity values for a pair of species that allow the toxicity of multiple species to be predicted from a single measured acute toxicity value for a surrogate species. ICE SSDs were generated using four surrogate species (fathead minnow, Pimephales promelas; rainbow trout, Oncorhynchus mykiss; sheepshead minnow, Cyprinodon varigatus; and water flea, Daphnia magna). ICE-based hazard concentrations (HC5s) from the fifth percentile of the log-logistic distribution of toxicity values were compared to HC5s determined from the acute toxicity of 55 chemicals from USEPA Ambient Water Quality Criteria (AWQC). Measured fish and invertebrate acute toxicity data and HC5s from the AWQC datasets were compared to ICE-based HC5s. Surrogate species choice was found to be an important consideration in developing predictive HC5s. These results illustrated that fish predict fish better than invertebrates and D. magna predicted invertebrates better than most fish. For example, a mixed model of predicted fish and invertebrates from fathead minnow and D. magna as surrogate species provided predictive relationships with an average factor of 3.0 (± 6.7) over 7 orders of toxic magnitude and several chemical classes (HC5predjcted / HC5measured). The application of ICE models is recommended as valid approach for generating SSDs and hazard concentrations for chemicals with limited toxicity data.

Barron, Mace G., Sandy Raimondo, Christine Russom, Deborah N. Vivian and Susan H. Yee. 2008. Accuracy of Chronic Aquatic Toxicity Estimates Determined from Acute Toxicity Data and Two Time-response Models. Environ. Toxicol. Chem. 27(10):2196-2205. (ERL,GB 1324).

Traditionally, chronic toxicity in aquatic organisms and wildlife has been determined from either toxicity test data, acute to chronic ratios, or application of safety factors. A more recent alternative approach has been to estimate chronic toxicity by modeling the time course of mortality determined in standard acute toxicity tests, but these approaches have received limited validation. The uncertainty in chronic toxicity estimates from two time-response models, linear regression analysis (LRA) and accelerated life testing (ALT), was investigated using a dataset of over 150 matched species pairs of standard acute toxicity test data and measured chronic no observed effect concentration (NOEC) values. Chronic survival was more accurately modeled by both ALT (69%) and LRA (76%), than reproduction, growth or the most sensitive endpoint (50 to 60% accuracy). In general, LRA estimates of chronic toxicity were less conservative than ALT, with 66 to 79% of LRA estimates greater than the measured NOEC. Acute datasets with early mortality produced estimates of chronic survival that were more accurate (ALT: 92%; LRA: 89%) compared to all datasets, but were less conservative (ALT: 84% overestimated; LRA: 93%). Acute datasets with late mortality resulted in poor ALT and LRA estimates of chronic toxicity for all endpoints. Additional survival time measurements did not improve the accuracy of ALT or LRA estimates of chronic toxicity over the standard four acute measurement times (24, 48, 72, 96 hr). The time course of mortality should be considered when applying time-response models to estimate chronic aquatic toxicity, with greater accuracy likely for chronic survival than for growth or reproduction.

Raimondo, Sandy, Deborah N. Vivian, Charles Delos and Mace G. Barron. 2008. Protectiveness of Species Sensitivity Distribution Hazard Concentrations for Acute Toxicity Used in Endangered Species Risk Assessment. Environ. Toxicol. Chem. 27(12):2599-2607. (ERL,GB 1330).

A primary objective of threatened and endangered species conservation is to ensure that chemical contaminants and other stressors do not adversely affect listed species. Assessments of the ecological risks of chemical exposures to listed species often rely on the use of surrogate species, safety factors, and Species Sensitivity Distributions (SSDs) of chemical toxicity; however, the protectiveness of these approaches is uncertain. We comprehensively evaluated the protectiveness of SSD 1st and 5th percentile hazard concentrations (HC1, HC5) relative to the application of safety factors using 68 SSDs generated from 1479 acute (LC50) toxicity records for 291 species, including 24 endangered species (20 fish, 4 mussels). SSD HC5s and HC1s were less than 98 and 100% of all endangered species mean acute LC50s, respectively. HC5s were significantly lower than the concentrations derived from applying safety factors of 5 and 10 to rainbow trout (Oncorhynchus mykiss) toxicity data and HC1s were generally less than the concentrations derived from a safety factor of 100 applied to rainbow trout toxicity values. Comparison of relative sensitivity (SSD percentiles) of broad taxonomic groups found that crustaceans were generally the most sensitive taxa and taxa sensitivity was related to chemical mechanism of action. Comparison of relative sensitivity of narrow fish taxonomic groups showed standard test fish species were generally less sensitive than salmonids and listed fish. We recommend the use of SSDs as a community-level risk assessment approach that is generally protective of listed species.

Raimondo, Sandy, Deborah N. Vivian and Mace G. Barron. 2009. Standardizing Acute Toxicity Data for Use in Ecotoxicology Models: Influence of Test Type, Life Stage, and Concentration Reporting. Ecotoxicology. 18(7):918-928. (ERL,GB 1350).

Ecotoxicological models generally have large data requirements and are frequently based on existing information from diverse sources. Standardizing data for toxicological models may be necessary to reduce extraneous variation and to ensure models reflect intrinsic relationships. However the extent to which data standardization is necessary remains unclear, particularly when data transformations are used in model development. An extensive acute toxicity database was compiled for aquatic species to comprehensively assess the variation associated with acute toxicity test type (e.g. flow-through, static), reporting concentrations as nominal or measured, and organism life stage. Three approaches were used to assess the influence of these factors on log-transformed acute toxicity: toxicity ratios, log-linear models of factor groups, and comparison of Interspecies Correlation Estimation (ICE) models developed using either standardized test types or reported concentration type. In general, median ratios were generally less than 2.0, the slopes of log-linear models were approximately one for well-represented comparisons, and ICE models developed using data from standardized test types or reported concentrations did not differ substantially. These results indicate that standardizing test data by acute test type, reported concentration type, or life stage may not be critical for developing ecotoxicological models using large datasets of log-transformed values.

Schimmel, Steven C., James M. Patrick, Jr. and Jerrold Forester. 1977. Toxicity and Bioconcentration of BHC and Lindane in Selected Estuarine Animals. EPA-600/J-77-070. Arch. Environ. Contam. Toxicol. 6(2/3):355-363. (ERL,GB 288). (Avail. from NTIS, Springfield, VA: PB-277 150)

Flow-through, 96-hr bioassays were conducted to determine the acute toxicity of technical BHC and lindane to several estuarine animals. Test animals and their respective 96-hr lindane LC50 values were: mysid (Mysidopsis bahia), 6.3 µg/L; pink shrimp (Penaeus duorarum), 0.17 µg/L; grass shrimp (Palaemonetes pugio), 4.4 µg/L; sheepshead minnow (Cyprinodon variegatus), 104 µg/L; and pinfish (Lagodon rhomboides), 30.6 µg/L. The 96-hr LC50 values for pink shrimp and pinfish exposed to BHC were 0.34 and 86.4 µg/L, respectively. Two BHC bioconcentration studies were conducted with the oyster, Crassostrea virginica, and pinfish. After 28 days exposure, oysters bioconcentrated an average of 218 X the BHC measured in exposure water, while pinfish bioconcentrated 130 X in their edible tissues and 617 X in offal. After one week in BHC-free sea water, no detectable residues were measured in oysters or pinfish.

Schimmel, S.C., J.M. Patrick, Jr. and A.J. Wilson, Jr. 1977. Acute Toxicity to and Bioconcentration of Endosulfan by Estuarine Animals. In: Aquatic Toxicology and Hazard Evaluation, ASTM STP 634. F.L. Mayer and J.L. Hamelink, Editors. American Society for Testing and Materials, Philadelphia, PA. Pp. 241-252. (ERL,GB 289).

Acute (96-h) flow-through toxicity tests with endosulfan (Thiodan) were conducted with several estuarine animals. The test species and their 96-h lethal concentration for 50% of the organisms (LC50) values were: pink shrimp (Penaeus duorarum), 0.04 µg/litre; grass shrimp (Palaemonetes pugio), 1.3 µg/ litre; pinfish (Lagodon rhomboides), 0.3 µg/litre; spot (Leiostomus xanthurus), 0.09 µg/litre; and striped mullet (Mugil cephalus), 0.38 µg/litre. In a 56-day bioconcentration study (28-day uptake, 28-day depuration), striped mullet were exposed to 0.008 And 0.08 µg endosulfan/litre seawater. The two endosulfan isomers (endosulfan I and II) were rapidly metabolized to endosulfan sulfate; only trace amounts of each isomer were detected in edible tissue or offal of mullet exposed to 0.08 µg/litre (0.035 µg/litre measured) for 28 days. Maximum bioconcentration factors of endosulfan were 2249 in edible tissue and 2755 in whole-body analyses. After 48 h in pesticide-free seawater, endosulfan was not detected in the previously exposed mullet. Our studies suggest that endosulfan in the estuarine environment would be a hazard because of its acute toxicity and bioconcentration potential, but animals surviving exposure and moving to areas free of endosulfan would lose the chemical rapidly.

Schimmel, Steven C. and Alfred J. Wilson, Jr. 1977. Acute Toxicity of Kepone to Four Estuarine Animals. Chesapeake Sci. 18(2):224-227. (ERL,GB 293).

Recent contamination of the James River Estuary, Virginia, with Kepone prompted acute flow-through bioassays to determine the 96-hour toxicity of the insecticide to four estuarine species native to that ecosystem. The species and their 96-hour LC50 values were: grass shrimp (Palaemonetes pugio), 121 µg/ liter; blue crab (Callinectes sapidus) >210 µg/liter; sheepshead minnow (Cyprinodon variegatus),, 69.5 µg/liter; and spot (Leiostomus xanthurus) 6.6 µg/ liter. Surviving animals were analyzed for Kepone. Average bioconcentration factors (the concentration of Kepone in tissues divided by the concentration of Kepone measured in seawater) were: grass shrimp, 698; blue crab, 8.1; sheepshead minnow, 1,548; and spot, 1,221.

Hansen, D.J., D.R. Nimmo, S.C. Schimmel, G.E. Walsh and A.J. Wilson, Jr. 1977. Effects of Kepone on Estuarine Organisms. In: Recent Advances in Fish Toxicology, a Symposium. EPA-600/3-77-085. U.S. Environmental Protection Agency, Environmental Research Laboratory, Corvallis, OR. Pp. 20-30. (ERL,GB 311).

Laboratory toxicity tests were conducted to determine the effects and accumulations of Kepone in estuarine algae, mollusks, crustaceans, and fishes. Nominal Kepone concentrations calculated to decrease algal growth by 50% in static bioassays lasting seven days were: 350 µg/l, Chlorococcum sp.; 580 µg/l, Dunaliella tertiolecta; 600 µg/l, Nitzschia sp.; and 600 µg/l, Thalassiosira pseudonana. Measured Kepone concentrations calculated to cause 50% mortality in flowing-seawater toxicity tests lasting 96 hours were: 10 µg/l for the mysid shrimp (Mysidopsis bahia); 120 µg/l for the grass shrimp (Palaemonetes pugio); >210 µg/l for the blue crab (Callinectes sapidus); 70 µg/l for the sheepshead minnow (Cyprinodon variegatus); and 6.6 µg/l for the spot (Leiostomus xanthurus). Bioconcentration factors (concentration in whole animals divided by concentration measured in water) in these tests were greatest for fishes (950 to 1,900) and less for grass shrimp (420 to 930). Survival, growth, and reproduction of mysids and sheepshead minnows were decreased in chronic bioassays lasting 14 to 64 days. Growth of mysids and sheepshead minnows in the chronic bioassay averaged 5,200 (range, 3,100-7,000) for adults exposed for 28 days and 7,200 (3,600-20,000) for juveniles exposed for 36 days. The chronic toxicity and bioconcentration potential of Kepone are more important factors than its acute toxicity in laboratory evaluations of environmental hazard. Therefore, these factors should be considered when attempting to assess present impacts and to limit future impacts of this insecticide on the aquatic environment.

Schimmel, Steven C., Timothy L. Hamaker and Jerrold Forester. 1979. Toxicity and Bioconcentration of EPN and Leptophos to Selected Estuarine Animals. EPA-600/J-79-086. Contrib. Mar. Sci. 22:193-203. (ERL,GB 354). (Avail. from NTIS, Springfield, VA: PB80-196017)

Acute (96-hr) flow-through toxicity tests, chronic (entire life-cycle) tests, and bioconcentration studies were conducted on selected estuarine animals with the insecticides, EPN, and leptophos. In the EPN acute toxicity tests, the test animals and their 96-h LC50 values were: Mysidopsis bahia, 3.44 µg/l; Penaeus duorarum, 0.29 µg/l; Cyprinidon variegatus, 188.9 µg/l; Lagodon rhomboides, 18.3 µg/l; and Leiostomus xanthurus, 25.6 µg/l. Test animals and 96-h LC50 values for leptophos were: M. bahia, 3.16 µg/l; P. duorarum, 1.88 µg/l; and L. xanthurus, 4.06 µg/l. In separate chronic tests, M. bahia were exposed to EPN and leptophos. Significant (a=0.05) mortality and fewer young were produced in 4.13 µg/l EPN. In the leptophos chronic test, significant mortality occurred in concentrations > or = 3.63 µg/l and fewer young were produced in concentrations > or = 1.77 µg/l. L. rhomboides, exposed to EPN in a 26-day uptake study, bioconcentrated the insecticide 707 X that measured in the exposure water. When L. rhomboides were held in EPN-free seawater, no EPN was detected in their tissues after eight days. L. xanthurus, exposed to leptophos for 26 days, bioconcentrated the insecticide to only 68 X the concentration in the exposure water. No leptophos residues were detectable in tissues after 4 days depuration. Our results indicate that if either insecticide contaminated an estuarine environment in concentrations > or = 1.0 µg/l, the most profound adverse effects on crustaceans and possibly fishes would result from acute toxicity, rather than from chronic toxicity or bioconcentration of the chemicals.

Scott, Geoffrey I. and Douglas P. Middaugh. 1978. Seasonal Chronic Toxicity of Chlorination to the American Oyster, Crassostrea virginica (G). In: Water Chlorination: Environmental Impact and Health Effects, Vol. 2. EPA-600/J-78-074. Robert L. Jolley, Hend Gorchev, and D. Heyward Hamilton, Jr, Editors. Ann Arbor Science Publishers, Ann Arbor, MI. Pp. 311-328. (ERL,GB 360). (Avail. from NTIS, Springfield, VA: PB-290 074)

Discharge of chlorine into estuarine and coastal waters may result in undesirable toxic effects to many of the organisms residing in these habitats. There is a substantial volume of information on short-term chlorination toxicity in marine invertebrates and fishes; however, little is known about the long-term effects of chlorination on the American oyster, Crassostrea virginica (G). Galtsoff reports that adult C. virginica showed reduced pumping rates at concentrations of chlorine of less than 0.05 mg/l. At concentrations of 1.00 mg/l or greater, oysters closed their valves and ceased to pump; the longest period of exposure, however, was only 48 hr. Recent work of Bongers et al reports little mortality in adult C. virginica exposed to chlorine (0.35-0.85 mg/l) and bromine chloride (BrCl) (0.17-0.86 mg/l) for 15 days. Sublethal responses revealed that new shell growth was greater in controls than in chlorine and BrCl-exposed oysters, with the amount of shell deposition decreasing with increased toxicant concentrations. No significant difference in the reduction of new shell deposition occurred in tests with chlorinated and BrCl-treated effluents. A study of the acute toxicity of chlorination to molluscan larvae revealed that chlorination is very toxic to both oyster (C. virginica) and clam (Mercenaria mercenaria) larvae. The 48-hr median effective concentration (EC50) was estimated to be less than 0.005 mg/l for larval oysters and 0.006 mg/l for larval clams. The estimated 96-hr EC50 (by shell deposition) for juvenile oysters was 0.023 mg/l. Oyster larvae survival under intermittent chlorination was much higher than for continuous chlorination. Products formed from chlorination of natural waters are a function of physical and chemical parameters of the water, including but not limited to temperature, pH, ammonia, sunlight (UV) and salinity (or the amount of bromine available as a reaction component). Since sea water typically contains 60 mg/kg bromide, bromination rather than chlorination may predominate as salinity increases. Thus, the chlorine-produced oxidant (CPO)12 levels measured during this study may include varying proportions of hypochlororus acid and hypochlorite ion, as well as hypobromous acid and hypobromite ion, depending upon the ambient salinity. In addition, photolysis may influence the level of bromate produced during chlorination of saline waters. The objective of this study was to examine the effects (lethal and sublethal) of chlorination to adult oysters, Crassostrea virginica, during chronic exposures on a seasonal basis.

Borthwick, Patrick W. and James M. Patrick. 1982. Use of Aquatic Toxicology and Quantitative Chemistry to Estimate Environmental Deactivation of Marine-Grade Creosote in Seawater. Environ. Toxicol. Chem. 1(4):281-288. (ERL,GB 421).

The acute toxicity of marine-grade creosote, expressed as the 96-h LC50, is 0.018 mg/l for mysids (Mysidopsis bahia, Molenock), .024 mg/l for pink shrimp (Penaeus durorum, Burkenroad), and 0.72 mg/l for sheepshead minnows (Cyprinodon variegatus, Lacepede). The 96-h EC50 (shell deposition) for Eastern oysters (Crassostrea virginica, Gmelin) is 0.71 mg/l. Mysid bioassays and chemical analyses estimate the half-life (<1 week) for marine-grade creosote in seawater.

Borthwick, P.W., J.R. Clark, R.M. Montgomery, J.M. Patrick, Jr. and E.M. Lores. 1985. Field Confirmation of a Laboratory-Derived Hazard Assessment of the Acute Toxicity of Fenthion to Pink Shrimp, Penaeus duorarum. In: Aquatic Toxicology and Hazard Assessment; Eighth Symposium, ASTM STP 891. EPA/600/D-85/033. R.C. Bahner and D.J. Hansen, Editors. American Society for Testing and Materials, Philadelphia, PA. Pp. 177-189. (ERL,GB 494). (Avail. from NTIS, Springfield, VA: PB85-169613)

Field studies were conducted to determine if laboratory protocols, accurately predict shrimp mortality under field conditions. To evaluate the applicability of laboratory data, fenthion, a mosquitocide, was applied to coastal black rush (Juncus roemerianus) marshes in several truck-mounted ultra-low volume (ULV) adulticide operations and by direct application at the larvicide rate. Caged pink shrimp (Penaeus duorarum) were deployed in floating, compartmented cages and observed frequently over a 24-h period for mortality. Water samples collected for gas chromatographic quantitation characterized the exposure concentration regime and fate of fenthion at the field sites. Field data were compared to laboratory acute toxicity data from ASTM standard practice flow-through tests. The acute flow-through 96-h LC50 of 0.11 µg/L was used as a conservative estimate of the expected toxicity in field exposures. An exposure profile based on measured field concentrations was used for laboratory pulse-exposure tests: fenthion was metered for 2 h to specified maximum concentrations, then flushed with seawater to cause a 6- to 8-h exposure, yielding a no-observed-effect concentration (NOEC) of 0.84 µg/L. In field tests, four ULV operations produced initial water concentrations NOEC) and caused extensive mortality (90 to 100%) in the caged shrimp. Thus, field observations confirmed our hypothesis that if fenthion time-exposure concentrations were lower than the laboratory NOEC, then no mortality would occur in caged shrimp. Moreover, if initial concentrations in the field exceeded the laboratory NOEC, mortality would occur. These laboratory tests and field applications indicate that laboratory toxicity tests can predict the range of lethal and nonlethal acute field exposures to fenthion for pink shrimp when exposure regimes are similar.

Couch, J.A. and W.J. Hargis, Jr. 1984. Aquatic Animals in Toxicity Testing. EPA-600/J-84-199. J. Am. Coll. Toxicol. 3(6):331-336. (ERL,GB 501).

Aquatic animals provide useful models for toxicological evaluations that bridge the gap between real world and laboratory problems. Select aquatic organisms are adaptable to laboratory experimentation in areas such as acute toxicity testing and chronic sublethal risks evaluation, including such phenomena as carcinogenesis, mutagenesis, and teratogenesis. General and specific examples of how aquatic animals are useful to toxicologists, as well as theoretical bases for their use, are discussed in this paper.

Duke, T.W. and P.R. Parrish. 1985. Toxicity Tests and Best Available Technology Determinations for Discharges from Offshore Oil and Gas Drilling Platforms. In: Proceedings of Eighth Annual Analytical Symposium, Norfolk,VA, April 3-4, 1985. United States. Environmental Protection Agency. Office of Water Regulations and Standards. Industrial Technology Division. Pp. 23-37. (ERL,GB 531).

Proposed guidelines for BAT regulations that govern the discharge of drilling fluids from offshore oil and gas platforms include a requirement for conducting an acute toxicity test with mysids, (Mysidopsis bahia), a small shrimp-like crustacean. The purpose of the test is to obtain an indication of the potential effect of a drilling fluid on marine organisms and additional tests with other organisms may be required by EPA Regional Offices under section 403-c of the Clean Water Act. The data from the BAT-related toxicity test are used to calculate the 96-hour LC50, i.e., the concentration of the drilling fluid that is lethal to 50% of test organisms exposed for 96 hours. This test was chosen, in part, because it is relatively simple to perform, mysids are generally available to testing laboratories, and these crustaceans are sensitive to toxic materials. Additionally, there is a large body of historic data concerning mysid toxicology which is useful for comparative purposes and the method has been routinely subjected to quality assurance calibration. The manner in which results from the toxicity tests can contribute to the BAT approach is illustrated by data developed recently by the EPA Environmental Research Laboratory at Gulf Breeze, Florida. Samples of drilling fluids collected from active wells in the Gulf of Mexico were screened for toxicity according to the BAT procedure. Some of the drilling fluid samples were more toxic than expected and their toxicity correlated well with the amount of "diesel" present in the samples. As a result of the screening tests, other organisms were tested and the data confirmed the relationship between toxicity and diesel content. The data indicate that toxicity of these drilling fluids could have been diminished through product substitution, i.e., by the use of a less toxic lubricating agent in the drilling fluids.

Clark, James R., James M. Patrick, Jr., Douglas P. Middaugh and James C. Moore. 1985. Relative Sensitivity of Six Estuarine Fishes to Carbophenothion, Chlorpyrifos, and Fenvalerate. EPA/600/J-85/336. Ecotoxicol. Environ. Saf. 10(3):382-390. (ERL,GB 541). (Avail. from NTIS, Springfield, VA: PB86-171634)

The acute toxicity (96-hr LC50) of carbophenothion, chlorpyrifos, and fenvalerate to six estuarine fishes was determined in flow-through laboratory tests. The atherinid fishes (Menidia menidia, M. peninsulae, M. beryllina, and Leuresthes tenuis) consistently were among the most sensitive species tested and were similar to each other in their sensitivity to pesticides. The sensitivity of sheepshead minnows (Cyprinodon variegatus) to carbophenothion was the same as that of the atherinids. For fenvalerate, the sheepshead minnow LC50 was an order of magnitude greater than that of the most sensitive atherinid, whereas the LC50 for chlorpyrifos and sheepshead minnows was two orders of magnitude greater. Gulf toadfish (Opsanus beta) were the least sensitive fish tested with carbophenothion and chlorpyrifos and their 96-hr LC50 for fenvalerate ranked between the LC50 for sheepshead minnows and atherinids. Test results were compared to acute toxicity data for other estuarine fishes and invertebrates.

Eaton, J., J. Arthur, R. Hermanutz, R. Kiefer, L. Mueller, R. Anderson, R. Erickson, B. Nordling, J. Rogers and H. Pritchard. 1985. Biological Effects of Continuous and Intermittent Dosing of Outdoor Experimental Streams with Chlorpyrifos. In: Aquatic Toxicology and Hazard Assessment: Eighth Symposium, ASTM STP 891. R.C. Bahner and D.J. Hansen, Editors. American Society for Testing and Materials, Philadelphia, PA. Pp. 85-118. (ERL,GB 566).

Two outdoor experimental streams fed by water pumped from the Mississippi River were dosed with the organophosphorus pesticide chlorpyrifos (the active ingredient of Dursban® and Lorsban 4E® insecticides) for 100 days, and the responses of individual species and communities compared to those of a control stream. Chlorpyrifos was continuously metered into one stream whereas the other received 8 biweekly additions, each lasting 24 h, at 14 times the concentration in the continuously dosed stream. Therefore, nearly equal amounts of pesticide were introduced into each stream during the experiment. The biological study area of each stream was approximately 245 m long, contained a naturally colonizing plant and invertebrate assemblage, and was stocked with fathead minnows and bluegills. Measured system characteristics included macroinvertebrate drift and riffle benthos composition; fish survival, growth, reproduction, food habits, tissue residues, and AChE inhibition; and system functional process indicators (P/R ratios, biodegradation, nitrate and dissolved organic carbon [DOC] concentrations, and bacterial growth and heterotrophic activity). The macroinvertebrate communities reacted similarly in the continuously and pulse-dosed streams. Species diversity decreased by equal amounts and was still decreasing at the end of the test. Crippling of fathead minnows and reversible acute toxicity symptoms (lethargy, tetany when startled) in bluegills were observed only in the pulse-dosed stream. Fish survived, reproduced, and grew equally well in all streams. There seemed to be good agreement between laboratory and field effect concentrations for fish and invertebrates. Functional process indices, with the possible exception of biodegradation, appeared unaffected and considerably less sensitive than other characteristics measured. The results of the project are discussed in relation to lab to field extrapolation and the need for further testing.

Parrish, P.R. and T.W. Duke. 1988. Variability of the Acute Toxicity of Drilling Fluids to Mysids (Mysidopsis bahia). In: Chemical and Biological Characterization of Sludges, Sediments, Dredge Spoils and Drilling Muds; ASTM STP 976. J.J. Lichtenberg et al., Editor. American Society for Testing and Materials, Philadelphia, PA. Pp. 326-333. (ERL,GB 596). (Avail. from NTIS, Springfield, Va: PB89-120026)

Numerous factors affect the acute toxicity of drilling fluids (muds) to mysids (Mysidopsis bahia). The source, composition, and age of drilling fluid sample; preparation of test material; condition of test animals; and skill and experience of the people conducting the tests can influence test results. Despite these confounding factors, our intralaboratory variation of median lethal concentrations (96-h LC50s) for six tests with a laboratory-prepared generic drilling fluid was within a factor of two; interlaboratory variation for seven commercial laboratories that tested the same generic drilling fluid was within a factor of four, the same as reported in the literature for acute toxicity tests with single chemicals. The presence of petroleum hydrocarbons in drilling fluids greatly increases toxicity and, because toxic, volatile fractions may be lost, variability of results from tests with petroleum hydrocarbon-contaminated drilling fluids may be greater than that stated above.

Goodman, Larry R., Geraldine M. Cripe, Paul H. Moody and Darrel G. Halsell. 1988. Acute Toxicity of Malathion, Tetrabromobisphenol-A, and Tributyltin Chloride to Mysids (Mysidopsis bahia) of Three Different Ages. EPA/600/J-88/278. Bull. Environ. Contam. Toxicol. 41(5):746-753. (ERL,GB 598). (Avail. from NTIS, Springfield, VA: PB89-208607)

Mysids (Mysidopsis bahia) of three ages (<= 1-, 5-, and 10-d-old at test initiation) were confined within the same aquaria and exposed to measured concentrations of malathion, tetrabromobisphenol-A, and tributyltin chloride in separate 96-hr acute toxicity tests. Sensitivities of the three age groups were similar. Ninety-six hour LC50 values ranged from 2.6 to 3.1 µg/L for malathion and from 1.1 to 2.2 µg/L for tributyltin chloride. The 96-hr LC50 for <= 1-d-old mysids exposed to tetrabromobisphenol-A was 860 µg/L, and approximately 50% of the 5- and 10-d-old mysids died at 1150 µg/L.

Parrish, Patrick R., John M. Macauley and Richard M. Montgomery. 1989. Acute Toxicity of Two Generic Drilling Fluids and Six Additives, Alone and Combined, to Mysids (Mysidopsis bahia). In: Drilling Wastes. EPA/600/D-88/004. F.R. Engelhardt, J.P. Ray, and A.H. Gillam, Editors. Elsevier Science, New York, NY. Pp. 415-426. (ERL,GB 617).

Toxicity tests were conducted with two laboratory-prepared generic drilling fluids (muds) and six commonly used drilling fluid additives to determine their toxicity, alone and combined, to mysids (Mysidopsis bahia). In 25 tests, the acute toxicity of combinations of one, two, or three of the drilling fluid additives mixed with either drilling fluid was less than the toxicity predicted from the empirical 96-h LC50s for drilling fluid additive(s) and/or drilling fluid alone; the observed 96-h LC50s of the mixtures were from 1.3 to 23.6 times the values predicted from the presumption of additive toxicity. Based on the drilling fluid additives and drilling fluids tested, a conservative estimate of the acute toxicity of mixtures of drilling fluid additives and drilling fluids would be derived if the toxicity of drilling fluid additive(s) and drilling fluid were separately determined and additive toxicity presumed.

Mayer, Foster L., Jr. and Mark R. Ellersieck. 1988. Experiences with Single-Species Tests for Acute Toxic Effects on Freshwater Animals. EPA/600/J-88/350. Ambio. 17(6):367-375. (ERL,GB 619). (Avail. from NTIS, Springfield, VA: PB89-237168)

Acute toxicity data developed over 20 years at one laboratory (Columbia National Fisheries Research Laboratory, U.S. Fish and Wildlife Service, Columbia, Missouri) were analyzed by various statistical approaches for taxonomic comparisons and to assess the degree to which various factors affected toxicity. The data base consisted of 4902 tests with 410 chemicals and 66 species of freshwater animals. Insects were the most sensitive group, followed by crustaceans, fishes, and amphibians. Of the factors affecting toxicity, the highest toxicity values were within 5 times or less the lowest values 80% or more of the time; this generalization included pH and temperature, evaluated on the basis of a 1.0 pH unit or 10° C change. Generalizations and predictions could be made for comparative toxicity and factors affecting toxicity equal to or greater than 80% of the time.

Cripe, Geraldine, Anne Ingley-Guezou, Larry R. Goodman and Jerrold Forester. 1989. Effect of Food Availability on the Acute Toxicity of Four Chemicals to Mysidopsis bahia (Mysidacea) in Static Exposures. EPA/600/J-89/037. Environ. Toxicol. Chem. 8(4):333-338. (ERL,GB 637). (Avail. from NTIS, Springfield, VA: PB90-103581)

The effect of nutritionally deficient Artemia nauplii on the growth of the mysid, Mysidopsis bahia, was evaluated in static systems. When Artemia nauplii with or without highly unsaturated fatty acid 20:5 w 3 were fed to 24-h-old M. bahia there was no difference in growth of mysids on either ration after 96 h of feeding. A study comparing amount of available food in static systems necessary for good survival and growth indicated that rations of 5, 10 or 30 Artemia per mysid per day (A/m/d) were different from 50, 70, 90 and 110 A/m/d as measured by dry weight. Static acute 96-h tests were conducted with <= to 24-h-old Mysidopsis bahia using either carbophenothion, cypermethrin, malathion, or 4-(tert-octyl)phenol. For each chemical, two replicate tests were conducted simultaneously with each of three rations of food provided. The rations chosen were 10 A/m/d, providing survival with minimal growth, a midpoint ration (60 A/m/d), and 110 A/m/d, clearly in excess of that necessary for good survival and growth. Only LC50s obtained in tests using 10 A/m/d were significantly different from other test results. These tests indicate that lack of food does adversely affect results of mysid static tests. In addition, excess food has the potential to reduce dissolved oxygen to nearly unacceptable concentrations.

Parrish, Patrick Rodney. 1989. Aquatic Toxicity Tests: The Bioassessment of Effluents Discharged to U.S. Surface Waters Is an Upward Trend. Environmental Lab. 1989(May):39-41. (ERL,GB 672).

Under Section 402 of the Clean Water Act, the U.S. Environmental Protection Agency (USEPA) issues permits that regulate discharge of effluents into navigable waters. In the second round of National Pollutant Discharge Elimination System (NPDES) permitting, USEPA proposed that acute toxicity tests be required on a case-by-case basis as a pollution-control parameter in the development of technology-based or water quality-based effluent limitations (Foster, 1984). This paper reviews a specific application of laboratory toxicity tests in a General Permit issued for the discharge of drilling fluids (muds) in the Gulf of Mexico and recent court rulings concerning the acceptability of the test procedures.

Hemmer, Michael J., Douglas P. Middaugh and Valerie Comparetta. 1992. Comparative Acute Sensitivity of Larval Topsmelt, Atherinops affinis, and Inland Silversides, Menidia beryllina to 11 Chemicals. EPA/600/J-92/209. Environ. Toxicol. Chem. 11(3):401-408. (ERL,GB 718). (Avail. from NTIS, Springfield, VA: PB92-195668)

Larval topsmelt (Atherinops affinis) and inland silversides (Menidia beryllina) were exposed in 96-hr static acute toxicity tests to eleven chemicals to determine the relative sensitivity to the two atherinid species. High to low LC50 ratios for endosulfan, methoxychlor, carbophenothion, chlorpyrifos, terbufos, fenvalerate, permethrin, 4-nitrophenol, and sodium lauryl sulfate were within a factor of < 2 for the two species. A. affinis was more sensitive to both azinphos-methyl and 2,4-dinitrophenol by factors of 6.7 and 4.4, respectively. Comparison of the relative sensitivity of A. affinis with three freshwater fish species (Lepomis macrochirus, Oncorhynchus mykiss, Pimephales promelas) and one estuarine fish species (Cyprinodon variegatus) are also presented. Sensitivities were similar between A. affinis and the two most sensitive freshwater species, L. macrochirus and O. mykiss. A. affinis is easily transported, cultured and maintained in the laboratory, and readily adaptable for use in toxicological studies.

Middaugh, D.P, L.R. Goodman and M.J. Hemmer. 1993. Methods for Spawning, Culturing, and Conducting Toxicity Tests with Early Life-Stages of Estuarine and Marine Fishes. In: Handbook of Ecotoxicology, Volume One. EPA/600/A-94/034. Peter Calow, Editor. Blackwell Scientific Publishers, Ltd., Oxford, England. Pp. 167-192. (ERL,GB 749). (Avail. from NTIS, Springfield, VA: PB94-155389)

This chapter provides a detailed description of the life history, geographical distribution, and procedures for laboratory spawning, culturing and testing of five fishes,the sheepshead minnow, Cyprinodon variegatus, the inland silverside, Menidia beryllina, Atantic silverside, M. menidia, California grunion, Leuresthes tenuis, and topsmelt, Atherinops affinis. Procedures for conducting acute toxicity tests (static and flow-through) as well as early life-stage toxicity tests are presented. Methods required for culturing of food organisms, the alga, Isochrysis galbana, rotifers, Brachionus plicatilus, and brine shrimp, Artemia salina, are also described. Tabular and diagrammatic data summaries of pertinent information required for utilization of each species in evaluation of environmental toxicants is presented. Suggestions are also given on species indigenous to South America, Western Europe, the Adriatic, Caspian, Mediterranean and Red Seas, the Persian Gulf, Japan and the Western Pacific which may be useful in the assessment of environmental pollutants in the regions.

Mayer, Foster L., Gary F. Krause, Denny R. Buckler, Mark R. Ellersieck and Gunhee Lee. 1994. Predicting Chronic Lethality of Chemicals to Fishes from Acute Toxicity Test Data: Concepts and Linear Regression Analysis. EPA/600/J-94/281. Environ. Toxicol. Chem. 13(4):671-678. (ERL,GB 764). (Avail. from NTIS, Springfield, VA: PB94-191079)

A comprehensive approach to predicting chronic lethality from acute toxicity data was developed in which simultaneous consideration is given to concentration, degree of response, and time course of effect. A consistent endpoint (lethality) and degree of response (0%) were used to compare acute and chronic tests. Predicted no-effect concentrations were highly accurate 92% of the time (within a factor of 2.0 of the limits of the maximum acceptable toxicant concentrations for lethality) and did vary by more than a factor of 4.8 when the technique was applied to a data base of 18 chemicals and 7 fish species. Growth effects can be predicted from chronic lethality, but reproductive or other chronic effects should not.

Howe, George E., Leif L. Marking, Terry D. Bills, Jeffrey J. Rach and Foster L. Mayer, Jr. 1994. Effects of Water Temperature and pH on Toxicity of Terbufos, Trichlorfon, 4-Nitrophenol, and 2,4-Dinitrophenol to the Amphipod Gammarus pseudolimnaeus and Rainbow Trout (Oncorhynchus mykiss). EPA/600/J-94/125. Environ. Toxicol. Chem. 13(1):51-66. (ERL,GB 778). (Avail. from NTIS, Springfield, VA: PB94-158748)

Acute toxicity tests were conducted to determine (a) the individual and interactive effects of water temperature (7, 12, 17°C), pH (6.5, 7.5, 8.5, 9.5), and time on the toxicity of terbufos, trichlorfon, 4-nitrophenol, and 2,4-dinitrophenol to rainbow trout (Oncorhynchus mykiss) and the amphipod Gammarus pseudolimnaeus, and (b) the individual and interactive effects of water temperature and pH on chemical bioconcentration during acute tests with rainbow trout and Gammarus exposed to terbufos, 4-nitrophenol, and 2,4-dinitrophenol. The toxicity of all four chemicals was significantly affected by pH in all tests, except for Gammarus exposed to terbufos. The toxicity of terbufos to rainbow trout and Gammarus was less at pH 7.5 than at higher or low pH. The toxicity of both nitrophenols decreased as pH increased, whereas the toxicity of trichlorfon increased with pH. The effect of pH on trichlolorfon toxicity decreased with temperature. Temperature significantly affected the toxicity of all four chemicals to both species. Toxicity increased with temperature in all tests, except for rainbow trout exposed to nitrophenols; toxicity decreased as temperature increased for rainbow trout. Chemical biocencentration was also significantly affected by temperature and pH and was directly related to toxicity in most tests. Significant interactive effects between toxicity-modifying factors were also frequently observed. Temperature and pH effects on chemical toxicity need to be considered in chemical hazard assessment to ensure adequate protection of aquatic organisms.

Brecken-Folse, Jeri A., Foster L. Mayer, Leslie E. Pedigo and Leif L. Marking. 1994. Acute Toxicity of 4-Nitrophenol, 2,4-Dinitrophenol, Terbufos, and Trichlorfon to Grass Shrimp (Palaemonetes spp.) and Sheepshead Minnows (Cyprinodon variegatus) as Affected by Salinity and Temperature. EPA/600/J-94/126. Environ. Toxicol. Chem. 13(1):67-77. (ERL,GB 812). (Avail. from NTIS, Springfield, VA: PB94-158730)

Toxicities of 2 industrial chemicals (4-nitrophenol and 2,4-dinitrophenol) and 2 organophosphate insecticides (terbufos and trichlorfon) to juvenile grass shrimp (Palaemonetes spp.) and sheepshead minnows (Cyprinodon variegatus) were determined by static, 96-h toxicity tests in a factorial design with 12 combinations of salinity and temperature (15, 20, 25, 30 ppt x 17, 22, 27°C). Concentrations of the toxicants, including bioconcentration, were determined as appropriate by gas or liquid chromatography and the use of 14C-labeled compounds. The 96-h LC50s for 4-nitrophenol ranged from 12 to 31 mg/L and for 2,4-dinitrophenol from 13 to 50 mg/L. Toxicity decreased as salinity increased for 2,4-dinitrophenol and sheepshead minnows, but toxicity to grass shrimp increased as salinity increased. Toxicity decreased with increased temperature for grass shrimp exposed to 2,4-dinitrophenol and sheepshead minnows exposed to 4-nitrophenol, and no change was observed for grass shrimp exposed to 4-nitrophenol. Bioconcentration increased as concentration increased. The 96-h LC50s for terbufos ranged from 3.4 to 6.6 µg/L and for trichlorfon, from 6.3 to 19,300 µg/L. Terbufos and trichlorfon toxicity to grass shrimp and sheepshead minnows increased with increased temperature. Bioconcentration factors for terbufos were greater in sheepshead minnows than grass shrimp, but were reversed for trichlorfon.

Howe, George E., Leif L. Marking, Terry D. Bills, Michael A. Boogaard and Foster L. Mayer, Jr. 1994. Effects of Water Temperature on the Toxicity of 4-Nitrophenol and 2,4-Dinitrophenol to Developing Rainbow Trout (Oncorhynchus mykiss). EPA/600/J-94/128. Environ. Toxicol. Chem. 13(1):79-84. (ERL,GB 816). (Avail. from NTIS, Springfield, VA: PB94-158722)

Early life-stage (ELS) toxicity tests were conducted to determine the effect of selected water temperatures on the toxicity of 4-nitrophenol and 2,4-dinitrophenol to rainbow trout (Oncorphynchus mykiss). NOECs were determined for growth and mortality at selected time intervals and water temperature of 7, 12, and 17°C. As tests progressed, NOECs leveled to constant time-independent values that were similar for tests at each temperature. In 4-nitrophenol tests, the time-independent NOEC values at 7, 12, and 17°C, respectively, were 1.16, 1.20 and 1.16 mg/L for growth and 3.40, 3.38, and 2.20 mg/L for mortality. For 2,4-dinitrophenol, time-independent NOEC values 7, 12, and 17°C, respectively, were 1.07, 0.50, and 0.80 mg/L for growth and 1.30, 1.89, and 1.60 mg/L for mortality. Temperature did, however, affect the rate at which time-independent NOECs were reached. More time was required to reach time-independent NOECs as temperature decreased. For example, the time-independent NOEC in 4-nitrophenol tests at 17°C was reached in 14 d, whereas it required 42 d at 7°C. The effect of temperature on toxicity must be considered in hazard assessment protocols to assess risk accurately and protect aquatic organisms adequately. Chronic toxicity tests are necessary to assess risk because acute toxicity tests cannot provide the information necessary to predict the long-term effects of factors such as temperature in natural environments.

Lee, Gunhee, Mark R. Ellersieck, Gary F. Krause and Foster L. Mayer. 1995. Predicting Chronic Lethality of Chemicals to Fishes from Acute Toxicity Test Data: Multifactor Probit Analysis. Environ. Toxicol. Chem. 14(2):345-349. (ERL,GB 827).

New methods for predicting chronic toxicity (lethality) from acute lethality data with fishes were developed and assessed. Typically, acute toxicity tests with aquatic organisms provide lethality estimates for a series of toxicant concentrations at 24, 48, 72, and 96 h of exposure. Statistical models (multiple regression) were developed that utilize acute toxicity data to establish the relation of lethality to toxicant concentration and exposure time for predicting chronic lethality. The models provide estimates of toxicant concentrations that result in a low probability of death as a function of extended exposure times. Results from 28 data sets having lethality data for both acute and chronic exposures were used to evaluate the method. It is posited that the proposed methods are highly accurate when acute lethality data meeting stated quality requirements are available.

Sun, Kai, Gary F. Krause, Foster L. Mayer, Mark R. Ellersieck and Asit P. Basu. 1995. Estimation of Acute Toxicity by Fitting a Dose-Time-Response Surface. EPA/600/J-95/374. Risk Anal. 15(2):247-252. (ERL,GB 838).

In acute toxicity testing, organisms are continuously exposed to progressively increasing concentrations of a chemical and deaths of test organisms are recorded at several selected times. The results of the test are traditionally summarized by a dose-response curve, and the time course is usually ignored for lack of a suitable model. A model which integrates the combined effects of dose and exposure duration on response is derived from the biological mechanisms of aquatic toxicity, and a statistically efficient approach for estimating acute toxicity by fitting the proposed model is developed in this paper. The proposed procedure has been computerized as software and a typical data set is used to illustrate the theory and procedure. The new statistical technique is also tested by a data base of a variety of chemical and fish species.

Cripe, Geraldine M. 1994. Comparative Acute Toxicities of Several Pesticides and Metals to Mysidopsis bahia and Postlarval Penaeus duorarum. Environ. Toxicol. Chem. 13(11):1867-1872. (ERL,GB 868).

Effects of toxic chemicals on estuarine and marine crustaceans are often evaluated using the mysid, Mysidopsis bahia. In a literature survey of results of acute toxicity tests with estuarine crustaceans, Mysidae and Penaeidae were generally the two most sensitive families. However, neither family was consistently more sensitive (higher LC50 divided by lower LC50 >2). Mysids were 54 times more sensitive to pyrethroids than penaeids, compared across three chemicals (N=3 studies). Yet penaeids were 36 times more sensitive (N=4 studies) to organochlorines and 5 times more sensitive (N=17 studies) to organophosphates than mysids. Acute exposures of < or = 24-h-old mysids and second post larvae of the pink shrimp, Penaeus duorarum, were conducted to compare responses of these estuarine crustaceans to each other and to values from the literature of other crustaceans tested with the same chemicals. The test compounds were chloride salts of cadmium, copper and zinc; the organophosphates: diazinon, fenthion and malathion; and several pyrethroids: cypermethrin, fenvalerate and permethrin. Results showed that pyrethroid toxicity was similar to mysids and post larval pink shrimp, organophosphate toxicity was within a factor of 2.7 for both species and mysids were approximately 3 to 26 times more sensitive to the metals than larval pink shrimp.

Middaugh, D.P., R.L. Thomas, S.E. Lantz, C.S. Heard and J.G. Mueller. 1994. Field-Scale Testing of a Hyperfiltration Unit for Removal of Creosote and Pentachlorophenol from Ground Water: Chemical and Biological Assessment. EPA/600/J-94/280. Arch. Environ. Contam. Toxicol. 26(3):309-319. (ERL,GB 888). (Avail. from NTIS, Springfield, VA: PB94-191061)

Chemical analyses and biological response data were used to assess the efficacy of a field-scale hyperfiltration unit in the removal of polylcyclic aromatic hydrocarbons (PAHs) and other organic compounds from creosote- and pentachlorophenol (PCP)-contaminated ground water recovered from the former American Creosote Works in Escambia County, Pensacola, Florida. The hyperfiltration unit consisted of 4 modules containing porous stainless steel tubes which were coated with a formed-in-place zirconium hydrous oxide-polyacrylic acid (ZOPA) membrane. A 5-fold concentraion of the feedwater (80% volume reduction) with up to 97% removal of high molecular weight PAHs was achieved during pre-demonstration and field-demonstration runs of the hyperfiltration unit. Approximately 68% of PCP was removed by the unit. Performance for phenolics was less successful, averaging 27 and 36%, respectively for the two runs. Toxicological and teratogenic data for embryonic inland silversides, Menidia beryllina, indicated that 100, 10 and 1% solutions of the ground water sample used in the pre-demonstration run caused statistically significant (p < or = 0.05) biological responses when compared to controls. However, the 1% solution of permeate in the pre-demonstration run was nontoxic and not teratogenic. This 1% solution was also not very toxic in Microtox® tests. The 5 min EC50 was 56.44%. Acute toxicity tests with Ceriodaphnia dubia revealed a 48 h LC50 of greater than 1% permeate. Similar results were obtained in the field-demonstration run of the hyperfiltration unit. In this run, feedwater was toxic or teratogenic to Menidia beryllina embryos at 100, 10 and 1% concentrations. Permeate from the field-demonstration run was embryo toxic or teratogenic at 100 and 10% concentrations but not at 1%. The Microtox® 5 min EC50 was 58.50% at the 1% concentration and the Ceriodaphnia 48 h LC50 was 5.6% permeate in the field-demonstration run. The Escambia County Utilities Authority (ECUA) set a pre-discharge requirement of non-toxicity to Ceriodaphnia dubia for 1% permeate solutions. Permeates from both runs, diluted to 1%, met the pre-condition of non-toxic responses in 48 h tests with Ceriodaphnia dubia. Meeting this requirement allowed for discharge of diluted permeate into the county's sanitary sewerage collector system.

Sun, Kai, Gary F. Krause, Foster L. Mayer, Jr., Mark R. Ellersieck and Asit P. Basu. 1995. Predicting Chronic Lethality of Chemicals to Fishes from Acute Toxicity Test Data: Theory of Accelerated Life Testing. Environ. Toxicol. Chem. 14(10):1745-1752. (ERL,GB 904).

A method for modeling aquatic toxicity data based on the theory of accelerated life testing and a procedure for maximum likelihood fitting the proposed model is presented. The procedure is computerized as software which can predict chronic lethality of chemicals using data from acute toxicity tests. A data base of a variety of chemicals and fish species was analyzed. When the calculated values of prediction were compared to the maximum acceptable toxicant concentrations obtained from actual chronic toxicity experiments, the new technique provided accurate predictions. Problems in using the "maximum acceptable toxicant concentration" and applications of the proposed method are discussed.

Whiting, V.K., G.M. Cripe and J.E. Lepo. 1996. Effects of the Anionic Surfactant, Sodium Dodecyl Sulfate, on Newly-Hatched Blue Crabs, Callinectes sapidus, and Other Routinely Tested Estuarine Crustaceans. Bull. Environ. Contam. Toxicol. 31(2):293-295. (ERL,GB 943).

This study describes the use of newly hatched larvae of Callinectes sapidus (blue crab) in a 48-h acute toxicity test and compares their sensitivity to two other estuarine crustaceans (Mysidopsis bahia and Palaemonetes pugio) commonly used for evaluation of effects of potentially toxic materials. C. sapidus larvae were twice as sensitive to sodium dodecyl sulfate as greater than or equal to 24-h-old P. pugio larvae. We found the blue crab toxicity test to be simple, rapid and accurate and it provides low variability and high reproducibility. Since the data indicate high sensitivity of this commercially important species to a reference toxicant and the potential impact on its survival during a critically sensitive developmental stage, we propose future research evaluating C. sapidus as a potential toxicity test species.

Middaugh, D.P., N. Beckham, J.W. Fournie and T.L. Deardorff. 1997. Evaluation of Bleached Kraft Mill Process Water Using Microtox(R), Ceriodaphnia dubia, and Menidia beryllina Toxicity Tests. Arch. Environ. Contam. Toxicol. 32(4):367-375. (ERL,GB 953).

To determine whether a 7 to 10-day embryo toxicity/teratogenicity test with the inland silverside fish Menidia beryllina is a sensitive indicator for evaluation of bleached kraft mill effluents, we compared this test with the Microtox® 15-minute acute toxicity test and the Ceriodaphnia dubia 7-day chronic toxicity test. Water samples used in each test were collected from three areas in a bleached kraft pulp and paper mill using a 100% chlorine dioxide bleaching process: 1) river water prior to use in the mill; 2) the combined acid/base waste stream from the pulping process prior to biological treatment in the aerated stabilization basin (ASB); and 3) the effluent from the ASB with a retention time of approximately 11 days. Relative toxicity determined by the three tests for each water sampling location was compared. All three toxicity tests were predictive; however, the C. dubia and M. beryllina tests were the more similar and sensitive indicators of toxicity. Process water (ASB influent) prior to biological treatment in the ASB was toxic at all concentrations using the Microtox® and C. dubia tests. The fish embryo test showed no toxicity at 1% concentrations, slight toxicity at 10%, and acute toxicity at the 100% ASB influent concentration. Tests with biologically treated ASB effluent indicated a substantial reduction in observed toxicity to Microtox® bacteria, C. dubia, and M. beryllina. No toxic responses were observed in any test at a 1% ASB effluent concentration, the approximate effluent concentration in the receiving river following mixing. No relationship was found among any toxicological response and effluent levels of adsorbable organic halides, polychlorinated phenolic compounds, 2,3,7,8-tetrachlorodibenzo-p-dioxin,2,3,7,8-tetrachlorodibenzofuran, total suspended solids, color, chemical oxygen demand, or total organic carbon.

Environmental Research Laboratory, Gulf Breeze, FL, Contributor. 1980. Ambient Water Quality Criteria for 2-Chlorophenol. EPA-440/5-80-034. U.S. Environmental Protection Agency, Office of Water Regulations and Standards, Washington, DC.. 39 p. (Avail. from NTIS, Springfield, VA: PB81-117459)

Aquatic life criteria: the available data for 2-chlorophenol indicate that acute toxicity to freshwater aquatic life occurs at concentrations as low as 4,380 microgram/l and would occur at lower concentrations among species that are more sensitive than those tested. No definitive data are available concerning the chronic toxicity of 2-chlorophenol to sensitive freshwater aquatic life but flavor impairment occurs in one species of fish at concentrations as low as 2,000 microgram/l. No saltwater organisms have been tested with 2-chlorophenol and no statement can be made concerning acute or chronic toxicity. Human health criteria: sufficient data is not available for 2-chlorophenol to derive a level which would protect against the potential toxicity of this compound. Using available organoleptic data, for controlling undesirable taste and odor qualitites of ambient water, the estimated level is O.1 Microgram/l. It should be recognized that organoleptic data as a basis for establishing a water quality criterion have limitations and have no demonstrated relationship to potential adverse human health effects.

Environmental Research Laboratory, Gulf Breeze, FL, Contributor. 1980. Ambient Water Quality Criteria for Polychlorinated Biphenyls. EPA-440/5-80-068. U.S. Environmental Protection Agency, Office of Water Regulations and Standards, Washington, DC. 117 p. (Avail. from NTIS, Springfield, VA: PB81-117798)

Aquatic life criteria: for polychlorinated biphenyls the criterion to protect freshwater aquatic life as derived using the guidelines is 0.014 Microgram/l as a 24-hour average. The concentration of 0.014 Microgram/l is probably too high because it is based on bioconcentration factors measured in laboratory studies, but field studies apparently produce factors at least ten times higher for fishes. The available data indicate that acute toxicity to freshwater aquatic life probably will only occur at concentrations above 2.0 Microgram/l and that the 24-hour average should provide adequate protection against acute toxicity. For polychlorinated biphenyls the criterion to protect saltwater aquatic life as derived using the guidelines is 0.030 Microgram/l as a 24-hour average. The concentration of 0.030 Microgram/l is probably too high because it is based on bioconcentration factors measured in laboratory studies, but field studies apparently produce factors at least ten times higher for fishes. The available data indicate that acute toxicity to saltwater aquatic life probably will only occur at concentrations above 10 microgram/l and that the 24-hour average criterion should provide adequate protection against acute toxicity.

Neff, Jerry M. 1981. Fate and Biological Effects of Oil Well Drilling Fluids in the Marine Environment: A Literature Review. EPA-600/3-82-064. U.S. Environmental Protection Agency, Environmental Research Laboratory, Gulf Breeze, FL. 150 p. (Avail. from NTIS, Springfield, VA: PB82-240391)

The major environmental concerns about discharge of used drilling muds to the ocean are that they may be acutely toxic or cause deleterious sublethal effects in sensitive organisms and ecosystems and that heavy metals associated with drilling muds may be accumulated by marine organisms to dangerous concentrations. A majority of major drilling mud ingredients are biologically inert or have a very low order of acute toxicity. Of the major drilling mud ingredients, only chrome- and ferrochrome-lignosulfonates can be considered at all toxic. Their toxicity is quite low to all but a few sensitive species (e.g., some corals). Minor ingredients of some environmental concern include sodium phosphate salts, detergents, biocides (chlorinated phenols no longer are permitted for offshore disposal), chromate salts and asphalt/oil-based ingredients. Ordinarily, these materials are not used in large enough quantities to cause concern. Their concentrations should be kept low in drilling muds destined for ocean disposal. Where possible, less toxic substitutes should be used. To date, the acute toxicity and sublethal biological effects of more than 20 used offshore-type drilling muds have been evaluated with more than 60 species of marine animals from the Atlantic, Pacific, Gulf of Mexico and Beaufort Sea. Representatives of five major animal phyla have been tested, including Chordata, Arthropoda, Mollusca, Annelida and Echinodermata. Larvae and other early life stages, and oceanic species (considered to be more sensitive than adults and estuarine species to pollutant stress) were included. In all but a few cases, acute toxicity, usually measured as 96-hr. LC50, was 10,000 ppm or higher drilling mud added. The lowest acute LC50 value was 500 ppm for stage I larvae of dock shrimp Pandalus danae exposed to a high density ferrochrome lignosulfonate drilling mud from Cook Inlet, Alaska. Chronic or sublethal responses were observed in a few cases at concentrations as low as 50 ppm.

Duke, T.W., P.R. Parrish, R.M. Montgomery, S.D. Macauley, J.M. Macauley and G.M. Cripe. 1984. Acute Toxicity of Eight Laboratory-Prepared Generic Drilling Fluids to Mysids (Mysidopsis bahia). EPA-600/3-84-067. U.S. Environmental Protection Agency, Environmental Research Laboratory, Gulf Breeze, FL. 27 p. (Avail. from NTIS, Springfield, VA: PB84-199850)

Acute toxicity tests were conducted during August-September 1983 with eight laboratory-prepared generic drilling fluids (also called muds) and mysids (Mysidopsis bahia) at the U.S. Environmental Protection Agency's Environmental Research Laboratory, Gulf Breeze, Florida. Two of the drilling fluids were tested at the Environmental Research Laboratory, Narragansett, Rhode Island, to confirm the validity of the tests conducted at Gulf Breeze. The test material was the suspended particulate phase (SPP) of each drilling fluid. The SPP was prepared by mixing volumetrically 1 part drilling fluid with 9 parts seawater and allowing the resulting slurry to settle for one hour. The material that remained in suspension was the SPP. Toxicity of the SPP of the drilling fluids ranged from a 96-hour LC50 (the concentration lethal to 50% of the test animals after 96 hours of exposure) of 2.7% for a KC1 polymer mud to 65.4% foor a lightly treated lignosulfonate mud. No median effect (50% mortality) was observed in three drilling fluids--a non-dispersed mud, a spud mud, and a seawater-freshwater gel mud. Two of the generic drilling fluids to which mineral oil had been purposely added were also tested at Gulf Breeze. The addition of the mineral oil increased the acute toxicity of each fluid to mysids. When 1% mineral oil was added, the 96-hour LC50 changed from 51.6% to 13.5% for fluid #2, a seawater lignosulfonate mud, and from 29.3% to 7.1% for fluid #8, a freshwater lignosulfonate mud. Addition of 5% and 10% mineral oil further increased toxicity.

New England Aquarium. 1984. Survey of the Toxicity and Chemical Composition of Used Drilling Muds. EPA-600/3-84-071. U.S. Environmental Protection Agency. Environmental Research Laboratory, Gulf Breeze, FL. 125 p. (Avail. from NTIS, Springfield, VA: PB84-207661)

Chemical characterization and toxicity of oil drilling fluids were investigated by the Edgerton Research Laboratory from Oct. 1, 1979 to Aug., 1983 as part of a comprehensive research program sponsored by the U.S. Environmental Protection Agency to determine fate and effects of such fluids in the marine environment. Drilling muds used were supplied by EPA, the Petroleum Equipment Suppliers Association, and the American Petroleum Institute. The drilling muds were designated 'May 15,' 'May 29,' 'Sept. 4,' 'Exxon,' 'Gilson,' 'Mobile Bay,' 'Jay Field,' and 'PESA.' Investigations during the first year centered on the chemical composition and acute toxicity of drilling muds, and the effects of drilling muds on recruitment of benthic organisms. In the second year, studies focused on toxicity testing with planktonic copepods, chemical characterization of toxicity test phases, bioaccumulation studies, and effects of muds on larval and adult benthic organisms. Investigations during the third and fourth year examined sublethal effects of drilling fluids on clam larvae, trace metal and organic constituents in both drilling fluids and toxicity test-phases, and preliminary development of a drilling fluid solid phase toxicity test. Toxic components of used drilling muds tested were present as dissolved components or associated with very slowly settling particles. Some used drilling muds contained lipophilic fractions that were similar to hydrocarbons found in #2 fuel oil in the liquid fraction and suspended particulates fraction and contained #2 fuel oil in whole muds. Muds that contained those components were more toxic than those that did not. Juvenile copepods (Acartia tonsa) were not more sensitive to toxic drilling mud solutions than adults of this species. In general, Cancer irroratus larvae appeared to exhibit toxicity responses to drilling muds that were similar to copepods tested. Arrested shell development induced by exposure to drilling muds appeared to be a sensitive indicator of stress in bivalve larvae. Total chromium concentration showed no correlation to toxicity in drilling muds that were tested; however, the highest concentrations of Cr(VI), the most biologically toxic form of chromium, occurred in test phases that exhibited the greatest toxicity to Mercenaria mercenaria larvae. The muds designated 'May 15' and 'Sept. 4' appeared to be relatively non-toxic to Pseudopleuronectes americanus and to Menidia menidia, although the 'May 15' mud was toxic to Neomysis americana and to Acartia tonsa. A study of effects of drilling mud on invertebrate recolonization of defaunated sediment showed that recolonization decreased in drilling mud layered on top of sediment when muds were mixed with sediments. Capitella capitata was much more numerous in recolonization sediments that contained drilling mud. Test results showed that methods used to prepare drilling mud test media affect the apparent toxicity of the muds.

Schimmel, Steven C. 1981. Results: Interlaboratory Comparison--Acute Toxicity Tests Using Estuarine Animals. EPA-600/4-81-003. U.S. Environmental Protection Agency, Environmental Research Laboratory, Gulf Breeze, FL. 14 p.

Environmental Protection Agency's Office of Pesticide and Toxic Substance (OPTS) is required by law to supply industry with recommended test standards to determine the toxicity of new chemicals. One proposed series of test standards is the acute toxicity test, flow-through and static, using estuarine animals. In proposing a test standard, OPTS requires knowledge of the precision of the data generated in these tests i.e., The expected variability in test results, given the same standard, test chemical and test species. This final report summarizes the results of static and flow-through toxicity tests conducted by six laboratories using the chemicals endosulfan and silver nitrate. Saltwater species tested were the copepod, Acartia tonsa, the mysid shrimp, Mysidopsis bahia and the sheepshead minnow, Cyprinodon variegatus. Results of the M. bahia and C. variegatus tests indicated that the mean ratio of the highest LC50 to the lowest LC50 generated for each chemical and test type was 4.0 (i.e. the greatest variability in the LC50 values expected was a factor of 4.0). Results of A. tonsa studies were not conclusive because different practices were used in the culture, age selection and testing of the species by the participating laboratories.

Burton, Dennis T. and Leonard B. Richardson. 1981. Investigation of the Chemistry and Toxicity of Ozone-Produced Oxidants and Bromate to Selected Estuarine Species. EPA-600/4-81-040. U.S. Environmental Protection Agency, Environmental Research Laboratory, Gulf Breeze, FL. 88 p. (Avail. from NTIS, Springfield, VA: PB82-116351)

This research program was initiated to determine the chemical and biological effects of ozone in estuarine systems and to evaluate its suitability as an alternative to chlorine. Chemical studies were performed to determine oxidant decay rates and bromate formation in both natural and artificial estuarine water. Ozonation of estuarine or marine waters can produce significant amounts of bromate if the natural levels of ammonia-nitrogen and other competing compounds are low and the initial residual oxidant and bromide concentrations are high. Toxicity studies showed that the concentrations of bromate which theoretically could be formed in an ozonated discharge were not toxic to the early life stages of striped bass (Morone saxatilis) and juvenile spot (Leiostomus xanthurus). Acute toxicity studies of ozone-produced oxidants (OPO) showed that the early larval stages of the American oyster (Crassostrea virginica) and recently hatched striped bass ichthyoplankton were most sensitive to OPO; this sensitivity decreased with progressive development. Juvenile blue crabs (Callinectes sapidus), juvenile Atlantic menhaden (Brevoortia tyrannus) and adult white perch (Morone americana) were more resistant than molluscan and ichthyoplankton larval stages. Hematological and gill histopathological sublethal studies of adult white perch showed that OPO caused death by hypoxia as a result of excessive gill damage. Moderately damaged gill tissue repaired itself within a few days when fish were moved to clean waters. A comparison of the ozone data obtained in this study with similar chlorine data from the literature showed that the toxicity of ozonated and chlorinated estuarine water is similar. Thus, ozone appears to offer few, if any, advantages over chlorine in reducing toxicity to estuarine organisms.

Environmental Research Laboratory, Gulf Breeze, FL. 1981. Acephate, Aldicarb, Carbophenothion, DEF, EPN, Ethoprop, Methyl Parathion, and Phorate: Their Acute and Chronic Toxicity, Bioconcentration Potential, and Persistence as Related to Marine Environments. EPA-600/4-81-041. U.S. Environmental Protection Agency, Environmental Research Laboratory, Gulf Breeze, FL. 255 p. (Avail. from NTIS, Springfield, VA: PB81-244477)

The toxicity, bioconcentration, and persistence of the pesticides acephate, aldicarb, carbophenothion, DEF, EPN, ethoprop, methyl parathion, and phorate were determined for estuarine environments. Static acute toxicity tests were conducted to determine the 96-h EC50 values for algae, 48-h EC50 values for oyster larvae, and 96-h LC50 values for at least two crustacean and fish species. Flow-through acute toxicity tests, based on measured concentrations, were conducted to determine the 96-h LC50 values of the pesticides for at least two crustacean and fish species. In addition, Maximum Acceptable Toxicant Concentrations (MATC) were determined in life-cycle toxicity tests with mysid shrimp (Mysidopsis bahia) and sheepshead minnows (Cyprinodon variegatus), or in partial life-cycle tests with grass shrimp (Palaemonetes pugio). MATCs were estimated from embryo-juvenile toxicity tests with sheepshead minnows. Persistence studies on carbophenothion, DEF, EPN, methyl parathion, and phorate investigated processes in marine systems that contribute to those pesticides' disappearance. The relative importance of biological and nonbiological processes (including biodegradation, photolysis, hydrolysis, sediment/water partitioning, and volatility) were examined. Bioconcentration factors for fish or mollusks exposed to carbophenothion, EPN, ethoprop, and phorate were determined at steady state or after greater than or equal to 28-day exposures.

Borthwick, Patrick W. and Gerald E. Walsh. 1981. Initial Toxicological Assessment of Ambush, Bolero, Bux, Dursban, Fentrifanil, Larvin, and Pydrin: Static Acute Toxicity Tests with Selected Estuarine Algae, Invertebrates, and Fish. EPA-600/4-81-076. U.S. Environmental Protection Agency, Environmental Research Laboratory, Gulf Breeze, FL. 9 p. (Avail. from NTIS, Springfield, VA: PB82-137654)

Selected static toxicity tests were conducted with Ambush, Bolero, Bux, Dursban, Fentrifanil, Larvin, and Pydrin to determine the sensitivity of species representing four major phyla. Algal bioassays were conducted with marine algae to determine the concentration of pesticide that would inhibit population growth by 50% in 96 h. Static toxicity tests with mollusk larvae estimated the concentration of pesticide that would cause 50% of the exposed larvae to develop abnormally in 48 h. Static acute lethality tests with crustaceans and fish determined the concentration of pesticide that is lethal to 50% of the test organisms during a 96-h exposure

Duke, T.W., P.R. Parrish, R.M. Montgomery, S.D. Macauley, J.M. Macauley and G.M. Cripe. 1984. Acute Toxicity of Eight Laboratory-Prepared Generic Drilling Fluids to Mysids (Mysidopsis bahia) (Project Summary). EPA-600/S3-84-067. U.S. Environmental Protection Agency, Environmental Research Laboratory, Gulf Breeze, FL. 4 p.

Besser, John M., F. James Dwyer, Chris G. Ingersoll and Ning Wang. 2001. Early Life-Stage Toxicity of Copper to Endangered and Surrogate Fish Species. EPA/600/R-01/051. U.S. Environmental Protection Agency, Office of Water, Washington, DC. 27 p. (Avail. from NTIS, Springfield, VA: PB2002-104609)

Water quality criteria (WQC) for the protection of aquatic life have not explicitly considered the degree of protection afforded to aquatic species listed as endangered or threatened under the U.S. Endangered Species Act (listed species). Most WQCs are based primarily on responses of a limited number of surrogate species, which are easily cultured and tested in the laboratory. Little information is available about the relative sensitivity of listed species to toxic chemicals, especially with respect to chronic toxicity. We conducted a series of chronic, early life-stage toxicity tests with two listed species, fountain darter (Etheostoma fonticola) and spotfin chub (Cyprinella monacha), and two surrogate species, fathead minnow (Pimephales promelas) and rainbow trout (Oncorhynchus mykiss), exposed to copper (Cu). Data from the tests with the four species, which included repeated tests with three species, were used to evaluate the suitability of test endpoints and toxicity metrics. Endpoints measured included survival, growth (total length and average dry weight of surviving fish), and biomass (total dry weight of survivors). Toxicity metrics were established by hypothesis testing to determine no-observed-effect concentrations (NOEC) and lowest-observed-effect concentrations (LOEC), and by a linear interpolation technique, to estimate inhibition concentrations associated with 10% and 25% reductions of test endpoints (IC10 and IC25). The hypothesis testing and linear interpolation methods generally gave similar results, as all calculable IC10 values fell within the NOEC-LOEC range. The "chronic value" calculated from these studies (ChV = geometric mean of NOEC and LOEC) corresponded closely to the IC10 for most species and endpoints. For three of the four species tested, growth and/or biomass endpoints were more sensitive than survival. For fountain darters, no significant effects on growth occurred at concentrations less than LOECs for survival and biomass, and IC10 values indicated that reductions in growth (both dry weight and total length) only occurred at concentrations greater than those affecting survival. For the other three species, reductions in growth, expressed as individual dry weight, occurred at concentrations at least as low as those affecting other endpoints. However, growth in dry weight showed wide variation among three tests with fathead minnows, with ChVs ranging from 2.8 to 15.9 µg/L. Results from tests with fathead minnows and other species suggested that growth in dry weight was affected by differences in fish density caused by differential survival among replicates and between treatments. Growth in total length was less variable than dry weight and LOECs for total length were close to those for dry weight, but IC10 values for total length were consistently greater than those for dry weight. Biomass, which reflects combined toxic effects of Cu on both survival and individual growth, was nearly as sensitive as growth in dry weight and was less variable among tests. Sensitivity to Cu toxicity did not differ substantially between listed and surrogate species. Lowest average ChVs for the four species tested ranged from 7.7 µg/L for the fountain darter (for reduced survival and biomass) to 15.9 µg/ L for the spotfin chub (for reduced growth and biomass). The average ChV for growth of fathead minnows from three tests (7.8 µg/L) was nearly equal to that for fountain darters, although this value was strongly influenced by the low ChV of 2.8 µg/L determined from one of the three tests. Evaluation of relative species sensitivities with IC10 produced similar results, with values ranging from <8.0 µg/L for fountain darters to 23 µg/L for spotfin chubs. Toxicity thresholds (either ChVs or IC10s) estimated from our chronic, early life-stage toxicity tests indicated that the current chronic Cu WQC would protect the endangered spotfin chub, but may not adequately protect the endangered fountain darter or the two surrogate species tested. This finding contrasts with results of previous acute toxicity tests in our laboratory, which concluded that current acute WQC for Cu would adequately protect fountain darters. These results suggest that protection of fountain darters from chronic toxicity of Cu would require application of a safety factor of about 0.5 to the current chronic Cu WQC. This safety factor would be consistent with that estimated from previous acute toxicity studies conducted at our laboratory with surrogate and listed species.

Buckler, Denny R., Foster L. Mayer, Mark R. Ellersieck and Amha Asfaw. 2003. Evaluation of Minimum Data Requirements for Acute Toxicity Value Extrapolation with Aquatic Organisms. EPA/600/R-03/104. U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Gulf Ecology Division, Gulf Breeze, FL. 60 p.

Assessment of risk posed by an environmental contaminant to an aquatic community requires estimation of both its magnitude of occurrence (exposure) and its ability to cause harm (effects). Our ability to estimate effects is often hindered by limited toxicological information. As a result, resource managers and environmental regulators are often faced with the need to extrapolate across taxonomic groups in order to protect the more sensitive members of the aquatic community. The goals of this effort were to: 1) compile and organize an extensive body of acute toxicity data, 2) characterize the distribution of toxicant sensitivity across taxa and species, and 3) establish appropriate toxicity extrapolation factors based upon toxicological relations among species and chemicals. The results of this effort allow for better use of available information for predicting the sensitivity of untested species to environmental contaminants. Three extensive databases containing acute toxicity information were obtained. The first was the combined acute toxicity database of the U.S. Geological Survey's Columbia Environmental Research Center and the U.S. EPA's Gulf Ecology Division. A second database was obtained from the U.S. EPA's Office of Pesticide Programs. The third database (EVISTRA, a component of the AQUIRE/ECOTOX database) was obtained from U.S. EPA's Office of Research and Development. In order to develop the most useful database for the purpose of evaluating toxicological relations across chemicals and taxa, it was necessary to standardize the information to be incorporated and establish a core data set. This was accomplished in a series of iterative steps. In general terms, data that were derived from studies that approximated the acute toxicity test conditions outlined by the American Society for Testing and Materials (2002) and/or the Committee on Methods for Toxicity Tests with Aquatic Organisms (1975) were retained, while other data were eliminated. This paring of information greatly reduced the number of data points retained, but served to eliminate variability that would have hindered discernment of toxicological relations. As part of this project, a software program entitled "Ecological Risk Analysis" (ERA) was developed. The utility of this program is to assign sensitivity rankings (as percentile values) to species with known acute toxicity values for a given chemical and then predict an acute toxicity value for theoretical species with designated sensitivities. For this effort we chose to focus on estimating LC50 values for the theoretical 5th percentile most-sensitive species. The ERA program was used to establish initial estimates of 5th percentile values using the core data sets. Subsequently, various extrapolation and prediction methods were evaluated in terms of their ability to estimate comparable 5th percentile values for severely limited data sets. While it is obviously desirable to have high quality acute toxicity values for as many species as possible for predicting toxicity values for sensitive members of the aquatic community, it is often necessary to make predictions for new or existing chemicals based upon limited data. The results indicate that the ERA program can be used with limited data sets to predict reasonable taxa-specific values for sensitive organisms. Further, if simple extrapolation from data on a single species must be used, the most satisfactory results were obtained with rainbow trout, bluegill, or scud.

Asfaw, Amha, Mark R. Ellersieck and Foster L. Mayer. 2003. Interspecies Correlation Estimations (ICE) for Acute Toxicity to Aquatic Organisms and Wildlife. II. User Manual and Software. EPA/600/R-03/106. U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Gulf Ecology Division, Gulf Breeze, FL. 14 p.

Predictive toxicological models, including estimates of uncertainty, are necessary to address probability-based ecological risk assessments. A method and software (ICE) were developed for estimating acute toxicity of chemicals to species, genera, and families when data are lacking. Interspecies correlation models for acute toxicity (4082 models) were derived for 143 aquatic and terrestrial organisms using Model II least squares regression, where both variables are independent and subject to measurement error (log X2=a+b[log X1). Toxicity of a chemical to one species can be predicted from toxicity to another species with known certainty. Correlations are generally best within a taxonomic family, decreasing with increasing taxonomic distance. However, certain species (e.g., rainbow trout) were found to be the most useful of all species for acute estimations among taxa, including families. Correlations for wildlife species were not as good, in general, as those for aquatic species, but routes of exposure are different -- oral or dietary versus respiratory, respectively.

Ellersieck, Mark R., Amha Asfaw, Foster L. Mayer, Gary F. Krause, Kai Sun and Gunhee Lee. 2003. Acute-to-Chronic Estimation (ACE v2.0) with Time-Concentration-Effect Models: User Manual and Software. EPA/600/R-03/107. U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Gulf Ecology Division, Gulf Breeze, FL. 20 p.

Predictive toxicological models, including estimates of uncertainty, are necessary to address probability-based ecological risk assessments. Methods and software (ACE) were developed for estimating chronic toxicity from raw acute toxicity data (all response observations at all times and exposures). Three methods were developed - - Accelerated Life Testing (ALT), Multifactor Probit Analysis (MPA), and two-stage Linear Regression Analysis (LRA). Of the three, the method of choice is ALT, in that time to failure (death) of each experiment unit is independent. It requires three partial responses over the time period of acute testing, but will function with one. The MPA is a two dimensional probit analysis using both time and concentration to produce a multiple regression equation, however, each experimental unit is not independent. Also, the MPA requires more partial responses than the ALT. The LRA calculates LC values for each time period and then regresses the LC values as the Y axis and the reciprocal of time as the X axis. The Y intercept is the chronic no-effect concentration. The LRA will function when ALT and MPA fail; no partial responses are required. All methods provide confidence limits for the point estimates. The methods have previously been shown to estimate chronic no-effect concentrations very well when validated against actual paired acute and chronic test results with fishes.

Mayer, Foster L., Gary F. Krause, Mark R. Ellersieck and Gunhee Lee. 1992. Statistical Approach to Predicting Chronic Toxicity of Chemicals to Fishes from Acute Toxicity Test Data. EPA/600/R-92/091//EPA/SW/DK-92/047. U.S. Environmental Protection Agency, Environmental Research Laboratory, Gulf Breeze, FL. 94 p. (Avail. from NTIS, Springfield, VA: PB92-169655; PB92-503119 with diskette)

A comprehensive approach to predicting chronic toxicity from acute toxicity data was developed in which simultaneous consideration is given to concentration, degree of response, and time course of effect. A consistent endpoint (lethality) and degree of response (0%) were used to compare acute and chronic tests. Predicted no-effect concentrations were highly accurate 92% of the time (within a factor of 2.0 of the limits of the maximum acceptable toxicant concentrations for lethality) and did not vary by more than a factor of 4.8 when the technique was applied to a data base of 18 chemicals and 7 fish species. Growth effects can be predicted from chronic lethality, but reproductive effects should not be.

Sun, Kai, Gary F. Krause, Foster L. Mayer, Jr., Mark R. Ellersieck and Asit P. Basu. 1994. Predicting Chronic Toxicity Based on the Theory of Accelerated Life Testing. EPA/600/R-94/058. U.S. Environmental Protection Agency, Environmental Research Laboratory, Gulf Breeze, FL. 33 p.

A method for modeling aquatic toxicity data based on the theory of accelerated life testing and a procedure for maximum likelihood fitting the proposed model is presented. The procedure is computerized as software, which can predict chronic lethality of chemicals using data from acute toxicity tests. A data base of a variety of chemicals and fish species was analyzed. When the calculated values of prediction were compared to the maximum acceptable toxicant concentrations obtained from actual chronic toxicity experiments, the new technique provided accurate predictions. Problems in using the 'maximum acceptable toxicant concentration' and applications of the proposed method are discussed.

Dwyer, F. James, Linda C. Sappington, Denny R. Buckler and Susan B. Jones. 1995. Use of Surrogate Species in Assessing Contaminant Risk to Endangered and Threatened Fishes. EPA/600/R-96/029. U.S. Environmental Protection Agency, Environmental Research Laboratory, Gulf Breeze, FL. 78 p. (EPA/600/X-92/139, Environmental Research Laboratory, Gulf Breeze, FL)

Surrogate species used in toxicity assessments must be carefully selected in order to be protective of listed species. At present, the rainbow trout is considered to be an acceptable surrogate for coldwater fishes. Similarly, the fathead minnow is considered to be an acceptable surrogate for warmwater fishes. This research project was designed to determine the applicability of using rainbow trout and fathead minnows as surrogate species for several endangered fishes. Coldwater static acute toxicity tests were conducted with rainbow trout and three listed species of salmonids - Apache trout (Oncorhynchus apache), Lahontan cutthroat trout (Oncorhynchus clarki henshawi), and greenback cutthroat trout (Oncorhynchus clarki stomias). Warmwater static acute toxicity tests were conducted with fathead minnow and two listed species of cyprinids - bonytail chub (Gila elegans) and Colorado squawfish (Ptychocheilus lucius). In addition, warmwater static tests were conducted with the razorback sucker (Xyrauchen texanus). Chemicals used in these toxicity assessments were selected in consultation with EPA to represent different chemical classes and toxic modes of action. Chemicals used in testing were: carbaryl, copper, 4-nonylphenol, pentachlorophenol, and permethrin. Results from the current studies indicated that the standard test organisms (rainbow trout and fathead minnows) often had a similar sensitivity to toxicant exposure as the listed salmonid and cyprinid species. The fathead minnow and the razorback sucker responses were generally similar. However, for 30% (8 of 27) of the possible surrogate/listed species comparisons, the standard 96-h LC50 for the listed species was lower than the surrogate species. After 96-h of exposure, warmwater listed species were more sensitive than fathead minnows 33 percent of the time. However, the listed warmwater species were always less sensitive than rainbow trout. Hazard assessments using rainbow trout would be protective of the warmwater species tested in this study. After 96-h of exposure, the listed salmonids were more sensitive than the rainbow trout for 25% of the comparisons. Environmental protection procedures usually focus on protection of populations or communities and not specific species or individuals of a species as may be necessary for endangered and threatened species. These data indicate an additional margin of safety may need to be included to protect listed salmonid species when toxicity assessments utilize data obtained from studies with rainbow trout.

Mayer, Foster L., Jr., Kai Sun, Gunhee Lee, Mark R. Ellersieck and Gary F. Krause. 1999. User Guide: Acute to Chronic Estimation. EPA/600/R-98/152. U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Gulf Ecology Division, Gulf Breeze, FL. 18 p.

Acute and chronic toxicity testing plays a major role in ecological risk assessment requirements involved in several environmental laws. Chronic toxicity tests commonly include the measurement of long-term effects of a contaminant on the survival, growth, and reproduction of test organisms. Such studies generally are expensive, high-risk investigations, sometimes requiring months to a year to conduct. Consequently, development of alternative estimation methods that provide similar information on chronic toxicity with less effort and expense is highly desirable. The Acute to Chronic Estimation (ACE) software application involves a major advancement in the area of ecological risk assessment and provides a reliable tool and technical basis to improve chronic prediction assessment for hazards. The ACE software package contains two statistical methods for predicting chronic lethality of chemicals to aquatic organisms from acute toxicity test data. The package was cooperatively developed by the U.S. Environmental Protection Agency (Gulf Ecology Division, NHEERL, ORD) and the University of Missouri-Columbia (Agricultural Experiment Station). Two articles describing the scientific basis and explaining the two methods were published in Environmental Toxicology and Chemistry.

Fulton, Michael H., Geoffrey I. Scott, Peter B. Key, G. Tom Chandler, Robert F. Van Dolah and Phillip P. Maier. 1999. Comparative Toxicity Testing of Selected Benthic and Epibenthic Organisms for the Development of Sediment Quality Test Protocols. EPA/600/R-99/085. U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Gulf Ecology Division, Gulf Breeze, FL. 52 p.

Sediment contamination has resulted in the need to develop an appropriate suite of toxicity tests to assess ecotoxicological impacts on estuarine ecosystems. Existing Environmental Protection Agency (EPA) protocols recommend a number of test organisms, including amphipods, polychaetes, molluscs, crustaceans and fish for use in sediment toxicity tests. While this suite of test animals represents a diverse group of fauna, many of the species recommended by the EPA are not indigenous to all geographic regions of the United States, particularly the Gulf of Mexico and South Atlantic. As a result, environmental risk assessment based on these organisms may not adequately protect ecosystem health in the Gulf of Mexico. Ideally, appropriate test organisms to evaluate sediment toxicity should include species indigenous to the Gulf of Mexico that are representative of a variety of faunal classes and feeding types. Additionally, the toxicity test endpoints should include both lethal (mortality) and sublethal (reproduction, growth, physiological impairment) effects and they should be sensitive to either porewater and/or whole sediment exposures for all major classes of chemical contaminants (trace metals, polycyclic aromatic hydrocarbons [PAHs], pesticides). Finally, test species should be easy to collect and maintain in the laboratory. This study examined the relative sensitivity of a variety of test organisms, broadly distributed throughout the southeastern United States and the Gulf of Mexico to several classes of chemical contaminants in both whole sediment and aqueous/porewater exposures. Additionally, several rapid screening assays were compared with these more traditional toxicity evaluations. The three model contaminants selected for study were cadmium (an inorganic toxicant), DDT (a persistent organochlorine pesticide) and fluoranthene (a polycyclic aromatic hydrocarbon [PAH]). These compounds represent contaminants frequently measured in sediments throughout the Gulf of Mexico. Overall, the juvenile clam was the most sensitive species tested in this study from an acute toxicity standpoint. The grass shrimp and the two amphipod species were generally similar in sensitivity to each of the three compounds. The copepod assay, although relatively insensitive in terms of adult mortality, was capable of detecting sublethal effects at contaminant concentrations below those which caused mortality in the other more sensitive species. Both the juvenile clam assay and the copepod partial life cycle test have the potential to serve as sensitive indicators of potential sediment-associated toxicity which might not be detected using standard acute toxicity bioassays. The differing species sensitivities observed with the different classes of chemical contaminants in this study suggest that a multiple species approach may be more appropriate for a holistic ecological risk assessment of sediment contamination. The "Crustacean Triad" (copepods, amphipods and grass shrimp) provide a battery of tests which predict toxicity to epibenthic and benthic crustaceans with known sensitivity to a variety of chemical contaminants and represent the base of the food chain for most recreationally and commercially important finfish species that utilize estuarine nursery grounds. The addition of the juvenile clam assay provides a herbivorous filter feeder with the ability to bioconcentrate pollutants and which is extremely sensitive in the size range tested (>212<350 µm). Field studies in South Carolina have indicated that sites with high sediment contaminant levels have degraded benthos, with significant effects observed in crustaceans and molluscs. These findings support our laboratory results and suggest that an integrated battery of assays may be most appropriate for estimating field effects.

Dwyer, F. James, Douglas K. Hardesty, Christopher E. Henke, Christopher G. Ingersoll, David W. Whites, David R. Mount and Christine M. Bridges. 1999. Assessing Contaminant Sensitivity of Endangered and Threatened Species: Toxicant Classes. EPA/600/R-99/098. U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Gulf Ecology Division, Gulf Breeze, FL. 15 p. (Avail. from NTIS, Springfield, VA: PB2000-197893)

Under the Federal Insecticide, Fungicide and Rodenticide Act, the Toxic Substances Control Act and the Clean Water Act, the U.S. Environmental Protection Agency (EPA) is charged with determining if the manufacture, use, or disposal of a chemical will present an unreasonable risk of harm to the environment. Typically, management decisions are based on protecting populations of organisms. However, the Endangered Species Act requires that, in some cases, managers must estimate the take of individuals to determine if the loss of individuals might adversely affect a population of an endangered or threatened (listed) species. The most direct assessment would be to determine the sensitivity of a listed species to a particular contaminant or perturbation. However, this direct approach would be time consuming and expensive because it might require development of organism culturing and handling procedures, some species may not be amenable to culture, there might be multiple species to be considered, and would be contaminant specific. The data we have generated indicates that in 96-h acute toxicity tests, if rainbow trout is used as a test species, a species typically used in pesticide registration or water quality criteria derivation, those procedures which protect the rainbow trout would likely be protective of most listed aquatic fish species. If a safety factor is needed to estimate 96-h LC50s for listed fish species, our data indicates that 0.5 would be a conservative estimator. Also, if EPA water quality criteria are recalculated by eliminating certain species from the data set, such as rainbow trout, then listed fish species might not be adequately protected.

Mayer, F.L., G.F. Krause, M.R. Ellersieck and G. Lee. 1992. Statistical Approach to Predicting Chronic Toxicity of Chemicals to Fishes from Acute Toxicity Test Data (Project Summary). EPA/600/SR-92/091. U.S. Environmental Protection Agency, Environmental Research Laboratory, Gulf Breeze, FL. 5 p.

Raimondo, Sandy and Mace G. Barron. 2007. Estimation of Chemical Toxicity to Wildlife Species Using Interspecies Correlation Models. Wildlife Toxicology Working Group Newsletter.(Winter/January):4-5. (ERL,GB R1135). (seen 6/11/2008)

Ecological risks to wildlife are typically assessed using toxicity data for only a few standard test species and with limited understanding of differences in species sensitivity to contaminants. lnterspecies Correlation Estimation (ICE) models were developed as log-linear least square regression models of the relationship between the acute toxicity (LD5O; mg/kg bodyweight) of a range of chemicals tested in two species. A total of 558 models were developed for 49 wildlife species and 951 chemicals. The standard wildlife test species Japanese quail (Coturnix) and mallard, and other avian species (redwinged blackbird, rock dove, ring-necked pheasant) were determined to be good surrogates for many species within the database. For mammals, Norway rat and house mouse provided good surrogacy. Cross-validation of all models predicted toxicity values within 5-fold and 10-fold of the actual values with 85% and 95% certainty, respectively. Taxonomic distance was inversely related to cross-validation prediction success (chisquare = 299.1, d.f. = 12, p <0.0001), with uncertainty increasing with larger taxonomic distance. Models built with two species within the same genus, family, or order predicted within 5-fold of the actual value with 90% confidence. Models were built with seven chemical model of action (MOA)/class or subgroups for species pairs with degrees of freedom > 50 in the original model. Average model error was not reduced by developing ICE models within most MOA/chemical class or subgroups; however improved models for carbamates and direct acting organophosphorouS acetylcholeneSterase inhibiting compounds indicate that toxicity estimates may improve if MONchemiCal älass specific models are built with robust datasets. ICE models can be used when toxicity data for a specific chemical are available for a selected surrogate species, and there is an existing model between the species pair of interest. ICE models for wildlife species provide a tool for estimating contaminant sensitivity with known levels of uncertainty for a diversity of wildlife species. The models described here, in addition to family-level ICE models, will be available in 2007 as a predictive modeling tool through the EPA Center for Exposure Assessment Modeling website (http://www.epa.gov/ceampubl/fchain/index.htm).

Block, Ronald M., Dennis T. Burton, Steven R. Gullans and Leonard B. Richardson. 1978. Respiratory and Osmoregulatory Responses of White Perch (Morone americana) Exposed to Chlorine and Ozone in Estuarine Waters. In: Water Chlorination: Environmental Impact and Health Effects, Vol. 2. Robert L. Jolley, Hend Gorchev, and Hamilton D. Heyward, Editors. Ann Arbor Science Publishers, Ann Arbor, MI. Pp. 351-360. (ERL,GB X007).

The use of ozone is being considered as an alternative to chlorine for disinfection purposes. Investigations on the comparative toxicity of chlorine and ozone were conducted to determine the acute toxicity of these oxidants to an euryhaline teleost. A relatively high concentration of these oxidants was used to elicit a physiological response from the white perch, Morone americana, exposed to a continuous flow of either chlorine or ozone. These studies were similar to that of chlorine.

Hansen, David J., Steven C. Schimmel, DelWayne Nimmo, Jack I. Lowe, Patrick R. Parrish and William H. Peltier. 1976. Continuous-Flow Method for Acute Toxicity Tests Using Fish and Macroinvertebrates. In: Bioassay Procedures for the Ocean Disposal Permit Program. EPA-600/9-76-010. U.S. Environmental Protection Agency, Environmental Research Laboratory, Gulf Breeze, FL. Pp. 69-80. (ERL,GB X080).

Continuous-flow (often referred to as 'flow-through') bioassays have definite advantages over static tests in evaluating certain types of wastes to be disposed of at sea. They are desirable in testing waste chemicals that have high biochemical oxygen demands, and are unstable or volatile. Many test species of fish and macroinvertebrates have high rates of metabolism and are difficult to maintain in jars or tanks of standing sea water. Continuous-flow bioassays, conducted under proper conditions, provide for well-oxygenated test solutions, nonfluctuating concentrations of the toxicant, and continual removal of metabolic wastes of the test organisms. This method provides general procedures for conducting a 96-hour, flow-through bioassay on marine fish and macroinvertebrates such as shrimp and crabs. Evaluation of different types of waste will, no doubt, require some modification of these procedures.

Hansen, David J., Steven C. Schimmel, DelWayne Nimmo, Jack I. Lowe, Patrick R. Parrish and William H. Peltier. 1978. Flow-Through Methods for Acute Toxicity Tests Using Fishes and Macroinvertebrates. In: Bioassay Procedures for the Ocean Disposal Permit Program. EPA-600/9-78-010. U.S. Environmental Protection Agency, Environmental Research Laboratory, Gulf Breeze, FL. Pp. 97-106. (ERL,GB X081).

Continuous-flow (often referred to as 'flow-through') bioassays have definite advantages over static tests in evaluating certain types of wastes to be disposed of at sea, particularly in testing waste chemicals that have high biochemical oxygen demands, and are unstable or volatile. Many test species of fish and macroinvertebrates have high rates of metabolism and are difficult to maintain in jars or tanks of standing sea water. Continuous-flow bioassays, conducted under proper conditions, provide for well-oxygenated test solutions, nonfluctuating concentrations of the toxicant, and continual removal of metabolic wastes of the test organisms. This method provides general procedures for conducting a 96-hour, flow-through bioassay on marine fish and macroinvertebrates such as shrimp and crabs. Evaluation of different types of waste will require some modification of these procedures.

Hansen, David J., Steven C. Schimmel, DelWayne Nimmo, Jack I. Lowe, Patrick R. Parrish and William H. Peltier. 1978. Static Method for Acute Toxicity Tests Using Fish and Macroinvertebrates. In: Bioassay Procedures for the Ocean Disposal Permit Program. EPA-600/9-78-010. U.S. Environmental Protection Agency, Environmental Research Laboratory, Gulf Breeze, FL. Pp. 89-96. (ERL,GB X082).

Hillebert, Susan A., B.J. Martin and R.D. Ellender. 1980. Exposure of a Teleost Cell Line to Suspected Carcinogens. J. Miss. Acad. Sci. 25:71-75. (ERL,GB X197).

Preliminary studies have evaluated the usefulness of a cell line from the sheepshead (Archosargus probatocephalus) as as carcinogen assay system. Acute toxicity levels have been established for three known mammalian carcinogens: benzo(a)pyrene, benzidine, and diethylnitrosamine. Long-term exposures have provided evidence that benzo(a)pyrene and benzidine have mutagenic effects on this cell line.

Tyler-Schroeder, Dana Beth. 1976. Effects of Two Polychlorinated Biphenyls, Aroclor 1016 and 1242, on the Grass Shrimp, Palaemonetes pugio. M.S. Thesis. University of West Florida, Pensacola, FL. 128 p. (ERL,GB X209).

The present study was initiated to investigate the separate effects of Aroclor 1016 and 1242 on larvae, postlarvae and adults of grass shrimp. Both short-term and long-term exposures during larval development were conducted to determine lethal and sublethal effects, with emphasis on toxicity during larval development. Objectives of the acute toxicity tests were: 1) Determine the 96-hour LC50 values for Aroclor 1016 and 1242 of several stages of the life cycle (e.g., larvae, postlarvae, and adults). A 96-hour LC50 value is that concentration of toxicant that is necessary to kill 50 per cent of the test population in a period of 96 hours. 2) Identify the most sensitive stage(s) of the life cycle. 3) Determine if there is a discernible pattern of susceptibility during larval development and metamorphosis to postlarvae. 4) Determine the relative toxicities of the two compounds tested. Objectives of the long-term exposure during larval development were: 1) Determine the median lethal chronic concentration during larval development. The median lethal chronic concentration is here defined as that concentration of toxicant necessary to kill 50 per cent of the test population during exposure from the time of hatching through larval development and metamorphosis to postlarvae. 2) Determine if there are sublethal chronic effects on growth and time of larval development, as measured by length of time necessary to complete metamorphosis to postlarvae and size of animal at this time. 3) Determine the relative chronic toxicity of the compounds being tested. The term chronic is used to imply a long-term test during larval development, as opposed to an acute, short-term (96-hour) exposure. It does not imply a long-term exposure from the juvenile stage, through maturation and reproduction, as used by some authors.

Laird, Chae E. and Morris H. Roberts, Jr. 1980. Effects of Chlorinated Seawater on the Blue Crab, Callinectes sapidus. In: Water Chlorination: Environmental Impact and Health Effects, Vol. 3. EPA-600/D-80-033. Robert L. Jolley, William A. Brungs, and Robert B. Cumming, Editors. Ann Arbor Science Publishers, Ann Arbor, MI. Pp. 569-579. (ERL,GB X212).

Physiological effect of chlorine-produced oxidants (CPO) are examined in tests with the blue crab, Callinectes sapidus Rathbun. Effects are assessed by determination of acute toxicity, changes in serum constituents, and changes in respiration of whole crabs and excised gills. The study indicates that adult blue crabs are more tolerant of CPO than other species, as reported in the literature. Respiration rate (oxygen consumption) was not measurably affected by exposure to CPO for either short (several hours) or long (up to 4 days) intervals even at CPO levels equal to or considerably above the observed 96-hr LC50. Ventilation rates were not increased to compensate for decreased oxygen diffusion across gill membranes at any dose of CPO. All but one measure of blood serum constituents failed to indicate any effect of CPO exposures on osmotic balance control even at doses exceeding the 96-hr LC50. The sole exception was serum magnesium, which increased significantly in crabs exposed to CPO at 1.04 mg/l i.e., above the 96-hr LC50.

Richardson, Leonard B., Dennis T. Burton, Ronald M. Block and Ann M. Stavola. 1983. Lethal and Sublethal Exposure and Recovery Effects of Ozone-Produced Oxidants on Adult White Perch (Morone Gmelin). EPA-600/J-83-017. Water Res. 17(2):205-213. (ERL,GB X370). (Avail. from NTIS, Springfield, VA: PB83-223644)

Adult white perch (Morone americana), acclimated to 15 degrees C, were exposed to a series of ozone-produced oxidant (OPO) concentrations for 96 h using continuous flow bioassay techniques. Toxicity data were analyzed using both response surface modeling and standard probit regression. White perch were also exposed to a series of near and sublethal OPO concentrations, selected from the acute toxicity study, for 96 h and then placed in clean non-ozonated water for 14 days. Blood pH, hematocrit and gill histopathology were analyzed during exposure at 24, 48 and 96 h and after 4 days in the recovery period. Blood pH and hematocrit levels were analyzed statistically using standard ANOVA and multiple range tests. Histopathological effects were examined using both light microscopy and scanning electron microscopy. The 24-, 48- and 96-h LC50's were 0.38, 0.26 and 0.20 mg OPO 1(-1), respectively. Blood pH was significantly reduced at concentrations greater than or equal to 0.15 mg OPO 1(-1) but not at 0.10 mg 1(-1) or lower concentrations. Hematocrit significantly increased at concentrations greater than or equal to 0.10 mg OPO 1(-1). Histopathological examination revealed minimal effects on gill tissue at 0.01 mg OPO 1(-1), moderate epithelial sloughing and heavy mucus production at 0.05 mg OPO 1(-1) and extreme tissue damage at concentrations greater than or equal to 0.10 mg 1(-1). Results from both the acute toxicity and the exposure and recovery study were compared with the effects of chlorine-produced oxidants (CPO) obtained from the literature. Both OPO and CPO appear to have similar effects on adult white perch.

Gaetz, Charles T., Richard Montgomery and Thomas W. Duke. 1986. Toxicity of Used Drilling Fluids to Mysids (Mysidopsis bahia). EPA/600/J-86/237. Environ. Toxicol. Chem. 5(9):813-821. (ERL,GB X392). (Avail. from NTIS, Springfield, VA: PB87-169579)

Static, acute toxicity tests were conducted with mysids (Mysidopsis bahia) and 11 used drilling fluids (also called drilling muds) obtained from active drilling platforms in the Gulf of Mexico in U.S. waters. Each whole mud was tested, along with three phases of each mud: a liquid phase with particulate materials removed, a suspended particulate phase composed of soluble and lighter particulate fractions and a solid phase composed mainly of drill cuttings and rapidly settling particulates. These muds represented seven of the eight generic mud types described by the U.S. Environmental Protection Agency for use on the U.S. Outer Continental Shelf. Based on volume:volume preparations of the drilling muds in seawater, the lowest 96-hour LC50s obtained were 26 ul/l for whole mud, 11,400 ul/L for the liquid phase, 726 ul/L for the suspended particulate phase and 1,456 ug/l for the solid phase. The toxicity of the 11 muds tested was apparently increased by the presence of aliphatic components.

Conklin, P.J., D. Drysdale, D.G. Doughtie, K.R. Rao, J.P. Kakareka, T.R. Gilbert and R.F. Shokes. 1983. Comparative Toxicity of Drilling Muds: Role of Chromium and Petroleum Hydrocarbons. EPA-600/J-83-107. Mar. Environ. Res. 10(2):105-125. (ERL,GB X398).

Samples of used drilling muds collected during the course of a single well drilling operation exhibited different degrees of acute toxicity to sheepshead minnows and grass shrimp. For molting grass shrimp Palaemonetes pugio, the 96-h LC50's were 360 to 14,560 ppm (ul/liter); many of these values were considerably lower than those reported from previous drilling mud assays. However, when some of the muds used in this study were tested on sheepshead minnows Cyprinodon variegatus, the resulting 96-h LC50's (6,300 to 100,000 ppm) were well within the range of previously reported values. Although a number of the drilling mud samples had relatively high amounts of chromium due to the addition of sodium chromate, there was a low correlation between chromium concentration and toxicity. In only three drilling muds could chromium content alone account for the observed toxicities. Furthermore, chemical analysis revealed the presence of No. 2 Fuel oil-like petroleum hydrocarbons in the mud samples. Based on the results of toxicity tests with No. 2 Fuel oil and the concentrations of oil present in the muds, the toxicity of the mud samples to grass shrimp appears to be largely attributable to the petroleum hydrocarbon content.

Middaugh, Douglas. 1985. Distribution, Life Cycle, Taxonomy, and Culture Methods: 4. Silversides (Menidia). In: Methods for Measuring the Acute Toxicity of Effluents to Freshwater and Marine Organisms (Third Edition). EPA/600/4-85/013. William H. Peltier and Cornelius I. Weber, Editors. U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, OH. Pp. 126-137. (ERL,GB X499).

Silversides occur in estuaries along the Atlantic and Gulf coasts. The Atlantic silverside, Menidia menidia, is a resident of estuaries from Maine to northern Florida. It occurs at intermediate to high salinities, typically of 12 to 30 parts per thousand (ppt), and remains in Atlantic estuaries throughout most of the year. Recent evidence indicates an offshore migration at northern latitudes in the fall and reappearance of adults in estuaries in late spring. This species is an important component in estuarine ecosystems, serving as forage fish for commercially and recreationally valued species such as striped bass, bluefish and spotted seatrout. Although culturing methods described in this section were written primarily for Menidia menidia, they are also suitable for the inland silverside, M. beryllina, and the tidewater silverside, M. peninsulae. The staff of the Environmental Research Laboratory, Gulf Breeze, Florida, is currently developing procedures for spawning, culturing, and testing of other fishes, including the California grunion, Leuresthes tenuis, and the Pacific surf smelt, Hypomesus pretiosus. The availability of these fishes as test organisms will permit the use of indigenous fish in toxicity tests of wastes discharged along the entire coast line of the contiguous United States and Alaska.

Takacs, Richard L., Richard B. Forward, Jr. and William Kirby-Smith. 1988. Effects of the Herbicide Alachlor on Larval Development of the Mud Crab Rhithropanopeus harrisii (Gould). EPA/600/J-88/285. Estuaries. 11(2):79-82. (ERL,GB X590). (Avail. from NTIS, Springfield, VA: PB89-209647)

The effects of the herbicide alachlor, in both technical grade and commercial product form (Lasso), were tested for acute toxicity on larvae of the estuarine crab Rhithropanopeus harrisii. The generalized effect is a reduction in survival and a lengthening of developmental time with an increase in concentration. The LC50 values were inversely proportional to exposure time and ranged from 10 to 27 ppm. Lasso was slightly more toxic than technical grade alachlor.

Scott, Geoffrey I., William P. Davis, J. Michael Marcus, Thomas G. Ballous and Jeffrey A. Dahlin. 1990. Acute Toxicity, Sublethal Effects, and Bioconcentration of Chlorination Products, Viruses, and Bacteria in Edible Shellfish: A Review. In: Water Chlorination: Chemistry, Environmental Impact, and Health Effects. Robert L. Jolley et al., Editor. Lewis Publishers, Chelsea, MI. Pp. 491-518. (ERL,GB X607). (Avail. from NTIS, Springfield, VA: PB89-142699)

This report identifies, synthesizes, and summarizes published scientific data concerning toxicity, sublethal physiological effects, and uptake/depuration rates of chlorine, viruses, and bacteria in edible marine shellfish of the United States. This summary may provide environmental managers with information related to coastal zone issues, such as point-source pollution permits, hazardous materials, material spills, and non-point-source runoff regulations.

Lee, Byung Mu and Geoffrey I. Scott. 1989. Acute Toxicity of Temephos, Fenoxycarb, Diflubenzuron, and Methoprene and Bacillus thuringiensis var. Israelensis to the Mummichog (Fundulus heteroclitus). Bull. Environ. Contam. Toxicol. 43:827-832. (ERL,GB X704).

The southeast United States has the single largest concentration of mosquito control efforts in the United States primarily due to the large concentration of fresh, brackish, and salt water marshes in these areas (NAS 1976). Salt marsh mosquitoes (Aedes sollicitans and Aedes taeniorhynchus) are the major mosquito pests along the entire Atlantic and Gulf Coast of the United States. Salt marsh mosquito control involves the application of chemical insecticides into breeding grounds, near estuarine tidal creeks, in an attempt to kill and control larval mosquitoes. The headwaters of many estuarine tidal creeks serve as nursery grounds for many fish species. The mummichog, Fundulus heteroclitus, is one of the dominant fish species present in these creeks. The application of chemical larvicides for mosquito control into salt marsh breeding grounds may pose a potential toxicity hazard to nontarget aquatic organisms. The larvicides generally recommended for use in South Carolina include: Abate (temephos), Dursban (chloropyrifos), Malathion, Altosid (methoprene), Pyrethrins, and Vectobac (Bacillus thuringiensis var. israelensis, Bti). Altosid and abate are among the most widely used larvicides in South Carolina and may be potentially toxic to nontarget species.

Moore, D.W., M.D. Schluchter and G.I. Scott. 1990. Use of Hazard Models in Evaluating the Effect of Exposure Duration on the Acute Toxicity of Three Pesticides. In: Aquatic Toxicology and Risk Assessment: Thirteenth Volume, ASTM STP 1096. EPA/600/A-95/010. W.G. Landis and W.H. van der Schalie, Editors. American Society for Testing and Materials, Philadelphia, PA. Pp. 247-263. (ERL,GB X799). (Avail. from NTIS, Springfield, VA: PB95-174710)

Renewal toxicity tests (96 h) were conducted with the emulsifiable concentrates of three pesticides: azinphosmethyl, endosulfan, and fenvalerate. A second test design, which incorporated a 6-h period of exposure followed by 90 h of observation, was also conducted on these three pesticides. Toxicity results from the two test types were then compared using different hazard modes to test a series of null hypotheses. These comparisons indicated: (1) while the effect of concentration was constant across time, hazard changed for each of the test types; and (2) when the effect of concentration was the same for the initial periods of exposure (6 and 24 h) in the two test designs, the average hazard was significantly lower for 6 h of exposure than for 24 h. This study may have significant implications for relating results from laboratory toxicity tests to mortality among organisms exposed in situ. The 6-h exposure test design provides information on delayed effects due to short-term exposures, while hazard analysis can be used to estimate the underlying time/concentration relationship from standard laboratory toxicity test data.

Weis, Judith S. and Peddrick Weis. 1996. Effects of Using Wood Treated with Chromated Copper Arsenate in Shallow-Water Environments: A Review. Estuaries. 19(2A):306-310. (ERL,GB X846).

Studies published over the past several years have documented that copper, chromium, and arsenic leach from pressure-treated wood placed in estuaries, and that these toxic metals accumulate in nearby sediments and biota. We have found bioaccumulation and deleterious effects in the epibiotic ('fouling') community, particularly in poorly flushed areas and on new wood. The epibiota showed reduced species richness, diversity, and biomass. Barnacles and encrusting bryozoa that settled on new treated wood grew more slowly than those that settled on untreated wood or plastic substrate. In laboratory studies, trophic transfer of the contaminants from epibiota to their consumers has also been demonstrated. We have also found accumulation of the treatment metals in the fine-grained fraction of nearby sediments and in the benthic infauna. Infauna also had reduced species richness and diversity in sediments adjacent to treated-wood structures. While standard toxicity tests with amphipods did not demonstrate acute toxicity of these sandy sediments, sublethal effects on development were seen in juvenile mysids. Overall, the extent and severity of effects of pressure-treated wood in an estuary depends on the amount and age of the wood and the degree of dilution by water movements.

Jonsson, Claudio M. and Fred J. Genthner. 1997. Evaluation of the Potential Pathogenicity and Toxicity of the Fungal Entomopathogen Colletotrichum gloeosporidoides Isolated from Orthezia to Two Species of Crustaceans. Bol. Pesqui. Embrapa-CNPMA. 1:1-27. (ERL,GB X917).

The mycoinsecticide Colletotrichum gloeosporioides isolated from the plant lice, Orthezia praelonga, has received special attention due to its success in controlling O. praelonga in citrus. Spore suspensions (106 spores/ml) of the fungus, produced on two different culture media, were evaluated for pathogenicity to embryos of the grass shrimp, Palaemonetes pugio. Culture filtrates and dried extracts of the fungus were also evaluated for acute toxicity to the microcrustacean, Artemia salina. No pathogenicity or adverse effects were observed in shrimp embryos exposed to C. Gloeosporioides spores, nor were culture filtrates or dried extracts of C. gloeosporioides toxic to A. salina.

Lewis, Michael, David Weber, Roman Stanley and Barbara Albrecht. 2000. Treated Wastewater as a Source of Sediment Contamination in Gulf of Mexico Near-Coastal Areas: A Survey. Environ. Toxicol. Chem. 19(1):192-203. (ERL,GB X967).

The primary objective of this baseline survey was to provide some needed perspective on the magnitude of sediment contamination associated with wastewater outfalls discharged to Gulf of Mexico near-coastal areas. The chemical quality and toxicities of whole sediments and pore waters collected from three coastal rivers and four coastal bays receiving wastewaters were assessed during a 2-year period. Rooted plants, invertebrates, and fish were used to assess the acute and chronic toxicities of sediments associated with a total of 10 industrial, municipal, steam electric-power generation and forest product wastewater outfalls. Effects of bacterial bioluminescence, early seedling biomass, survival, reproduction, fertility, and growth were determined in bioassays ranging from 30 min to 28 d duration. Sediment chemical contamination was localized and decreased with increasing distance from the discharge areas. The major sediment contaminants, with few exceptions, were divalent trace metals, which increase, on average, by 69% below 8 of the 10 outfalls. However, only a few concentrations exceeded proposed threshold sediment quality assessment guidelines. Toxicity to either the plant or animal test species was observed occasionally below 7 of the 10 outfalls, but its detection was dependent on the type of bioassay and the frequency of use. Consequently, a suite of bioassays conducted on multiple occasions appears to be needed for toxicity assessments of sediments collected below wastewater discharges in the Gulf region to ensure relevancy of the results. This is particularly true for low to moderately contaminated sediments where acute toxicity is uncommon, which was the case in this study.

Marchini, Silvia, Laura Passerini, Marilynn D. Hoglund, Anna Pino and Monika Nendza. 1999. Toxicity of Aryl- and Benzylhalides to Daphnia magna and Classification of Their Mode of Action Based on Quantitative Structure-Activity Relationship. Environ. Toxicol. Chem. 18(12):2759-2766. (ERL,GB X975).

The acute toxicity of aryl- and benzylhalides to Daphnia magna was investigated to test the validity of existing classification schemes for chemicals by mode of action, mainly based on fish studies, and the applicability of predictive quantitative structure-activity relationship (QSAR) models. Halobenzenes and halotoluenes are generally agreed to be unambiguous baseline toxicants (class I) with the major exception of the benzylic structures, which are reactive in fish tests (class III). Eighty-nine percent of the arylhalides tested in this study match a log Pow-dependent QSAR, including fluorinated, chlorinated, brominated, and iodinated derivatives, thereby confirming the validity of the baseline models also for variously halogenated compounds (other than only-chloro compounds). The toxicities of the benzylhalides relative to baseline QSARs clearly indicate that these compounds belong to two classes by mode of action, i.e., they either act as narcotic toxicants (class I) or reveal excess toxicity due to unspecific reactivity (class III). On some occasions, the assignment to the two classes in D. magna deviates from the structural rules derived from fish, i.e., iodinated compounds as well as a,a-Cl2-toluenes lack reactive excess toxicity but behave as nonpolar nonspecific toxicants. The QSARs derived during this study reveal lower slopes and higher intercepts than typical baseline models and, together with the analysis of mixture toxicity studies, behavioral studies, and critical body burden, advocate the hypothesis that there are several different ways to produce baseline toxicity. Most halobenzenes and halotoluenes are actually baseline chemicals with some extra reactivity and as such form a subgroup, whose limits still have to be defined. Different primary sites of action could explain why the chemicals are discriminated by different classification systems, but still they must have some rate-limiting interaction in common (e.g., lipid diffusion) as they fit the same log Pow-dependent baseline QSAR.

Mayer, Foster L., Denny R. Buckler, F. James Dwyer, Mark R. Ellersieck, Linda C. Sappington, John M. Besser and Christine M. Bridges. 2008. Endangered Aquatic Vertebrates: Comparative and Probabilistic-Based Toxicology. EPA/600/R-08/045. U.S. Environmental Protection Agency, Office of Research and Development, Washington DC. 33p. (ERL,GB X1109).

Many times, endangered, threatened, and candidate endangered species (collectively known as “listed” species) have been thought to be uniquely sensitive to chemicals. The purpose of this cooperative research effort (U.S. Environmental Protection Agency, U.S. Geological Survey, U.S. Fish and Wildlife Service, University of Missouri) was to determine: 1) if listed aquatic vertebrate species are more sensitive to chemicals than non-listed species; 2) if common surrogate test species represent listed species toxicologically; and 3) if predictive acute and chronic models can be applied to hazard assessments with listed species where direct toxicity testing is not prudent or impractical. Toxicity tests were conducted with 29 species of fishes and amphibians (endangered species and a set of surrogates) and five chemicals (carbaryl, copper, 4-nonylphenol, pentachlorophenol, and permethrin) representing a broad range of toxic modes of action. For acute toxicity, rainbow trout (Oncorhynchus mykiss), the most sensitive surrogate species, was equal to or more sensitive than listed and related aquatic vertebrate species 80% of the time. Only 3% of the species were significantly (P# 0.05) more sensitive than rainbow trout, and even then, the differences were within or very close to a factor of two (normal intra- and interlaboratory variation = 2-5x). Under similar environmental conditions, chronic toxicity tests with copper and pentachlorophenol indicated no significant greater sensitivity between rainbow trout and the listed species, spotfin chub (Cyprinella monacha) and fountain darter (Etheostoma fonticola). Using Interspecies correlation estimation (ICE) for estimating acute toxicity, 100% of the values for listed or related species were within or very close to a factor of two of the observed values (n = 70, mean = 1.1, range = 0.49 - 2.2). Acute-to-chronic (ACE) estimated chronic toxicity values were within a factor of two of observed values 80-90% of the time and 100% within a factor of three. Species sensitivity distributions (SSD) were also developed to determine the 5th percentile effect among observed data and different sets of estimated data. The most accurate estimated acute toxicity SSDs were in using the surrogate species having the best correlation model in ICE (SSD = 0.95x observed SSD; range = 0.88 - 0.98). SSDs for chronic toxicity were also quite good with ACE-estimated chronic data or ICE-estimated acute data/acute-chronic ratio. 5th percentile estimates averaged 0.95 times those for observed data (range = 0.46 - 1.3). The results suggest that listed aquatic vertebrate species are not universally more sensitive to contaminant exposure than other aquatic vertebrate species on a toxicological basis. Surrogate test species do appear to represent listed species toxicologically, at least for aquatic vertebrates, and toxicities and hazard assessments (SSD) can be estimated accurately and precisely, not only for listed species, but other species with little or no toxicity data as well.

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