Jump to main content or area navigation.

Contact Us

NPDES Permits in New England

OMSAP  LogoOutfall Monitoring Science Advisory Panel (OMSAP) Meeting

Wednesday, April 4, 2001, 10:00 AM - 2:00 PM
Woods Hole


Members Present: Andy Solow, WHOI (chair); Norb Jaworski, retired; Bob Kenney, URI; Scott Nixon, URI; Judy Pederson, MIT/Sea Grant; and Jim Shine, Harvard School of Public Health.

Observers: Bruce Berman, Save the Harbor/Save the Bay; Grace Bigornia-Vitale, MWRA; Peter Borrelli, Center for Coastal Studies; Jeanine Boyle, Battelle; Cathy Coniaris, MADEP; Peter DiMilla; David Dow, NMFS; David Duest, MWRA; Patricia Foley, Save the Harbor/Save the Bay; Maggie Geist, Association for the Preservation of Cape Cod; Dave Gilmartin, MWRA; Maury Hall, MWRA; Pam Heidell, MWRA; Carlton Hunt, Battelle; Russell Isaac, MADEP; Chris John, MWRA; Ken Keay, MWRA; Christian Krahforst, MCZM; Janet Labonte, EPA; Wendy Leo, MWRA; Scott Libby, Battelle; Matt Liebman, EPA; John Lipman, Cape Cod Commission; Steve Lipman, MADEP; Stormy Mayo, Center for Coastal Studies; Mike Mickelson, MWRA; Dale Miller, Normandeau Associates; Jack Pearce, Buzzards Bay Lab; Andrea Rex, MWRA; Seth Rolbein, Cape Cod Voice; Larry Schafer, retired; Jack Schwartz, MADMF; Ted Smayda, URI; Elizabeth Steele, MWRA; Steve Tucker, Cape Cod Commission; and David Wu, MWRA.


  • OMSAP recommends that the chlorophyll baseline for the annual threshold be calculated using a shifted calendar year that begins in September and ends in August. This would take into account the outfall start-up date, September 6, 2000, i.e. the year 2000 was an incomplete baseline year. January to August 1992 data will not be used for the calculation of the annual mean but will be used to calculate the seasonal means.
  • OMSAP approved the November 16, 2000 minutes with no amendments.


P. Foley, executive director of Save the Harbor/Save the Bay, introduced herself. She is pleased to be the newly elected chair of PIAC. PIAC’s plan is to promote a better understanding of the science so that public policy can better serve the public interest. PIAC is looking forward in working with OMSAP, and other interested parties, to make sure that the public workshop is productive and informative.

C. Coniaris gave a brief Model Evaluation Group (MEG) update. The MEG, formed in 1995, has been reconvened to review recent modeling results. There was a conference call to comment on a preliminary report on the calibration of the hydrodynamic model and there will be additional review this summer [Update: this review has been delayed, pending availability of modeling results]. Please contact C. Coniaris if you would like a copy of the MEG’s comments. MEG members are as follows: Bob Beardsley (WHOI, OMSAP, MEG chair), Eric Adams (MIT), Jeff Cornwell (U. Maryland), Don Harleman (MIT), Jack Kelly (EPA), Jay O’Reilly (NMFS), and John Paul (EPA Narragansett).

M. Liebman described the Contingency Plan, which is a plan for actions to be taken by the MWRA when thresholds are exceeded, and includes caution and warning thresholds for which to compare monitoring results to. The Contingency Plan is attached to the permit that was issued in August 2000, and is considered a “living” document in that it can be updated as new information becomes available without reopening the permit. The permit states that by Nov 15th of each year, the MWRA may request changes to the Contingency Plan, including thresholds. MWRA submitted a request for changes in October 2000 and EPA/MADEP have responded in a letter dated April 3, 2001 that describes how the agencies approve or disapprove of changes and includes some additional conditions that the MWRA should meet. The MWRA will submit a revised Contingency Plan within 30 days of today with those changes. He then summarized the April 3, 2001 EPA/MADEP letter [for a copy, contact catherine.coniaris@state.ma.us].

S. Tucker asked if there is an expectation that a standard for appreciable change for zooplankton will be developed or will it be based on professional judgment. He also asked if guidelines for appreciable change will be determined by MWRA and OMSAP. M. Liebman replied that it will be based on professional judgment and EPA/MADEP will rely on the current scientific findings in research and monitoring. Guidelines for appreciable change will be developed by MWRA and OMSAP but will be reviewed by EPA/MADEP.

T. Smayda said given that the model used assigns a certain percentage based on temperature and grazing extent, without coupling it to actual zooplankton biomass, it follows that there is no threshold, or a more rigorous statement as to what is defined as appreciable. M. Liebman replied that these issues will be evaluated in the next few years. There is ongoing research and monitoring and an effort and commitment by MWRA to look at the data that has been collected to determine any impacts to the zooplankton community. NOAA Fisheries has suggested that a trophic food web pathway workshop be convened soon to look at these issues, and follow-up on the ideas of a food web model. D. Dow supported T. Smayda in that there should be some process-oriented studies to augment the multivariate statistical analyses to learn more about meaningful change. If there is some kind of multivariate change, it may or may not be biologically significant. An event that is statistically significant is not necessarily biologically significant.

A. Solow thinks there is an expectation that conclusions will take into account existing scientific knowledge. Now is a good time to submit any suggestions in areas where there are concerns to MWRA, OMSAP, EPA, or MADEP. M. Liebman added that the workshop could be a good focal point for those ideas. Related to that, EPA, MWRA, and NOAA have funded Dr. Cabell Davis (WHOI) to conduct fine-scale monitoring of zooplankton communities using a Video Plankton Recorder [report located at: http://www.mwra.state.ma.us/harbor/enquad/pdf/2000-03.htm]

J. Shine asked if the new 100 cells/L Alexandrium threshold was chosen because 100 cell/L was exceeded only once in 10 years of baseline or if there was some objective understanding of a dose-response relationship between what cell counts would cause toxicity. M. Liebman replied that both aspects were taken into account, however, the dose-response is not clear enough yet. There is usually some kind of toxicity observed when 300 cells/L is exceeded. 100 cells/L was exceeded once in 10 years, similar, in a sense, to a 90th percentile. In other words, if this is exceeded in the future, chances are there is something occurring that is different from the baseline. He added that this threshold is a caution, meaning that if there is an exceedance, all ancillary data should be examined for a better understanding of the occurrence.

B. Berman asked if the MWRA will report annually on appreciable changes to the zooplankton community. A. Rex replied that the MWRA drafts annual reports that evaluate the zooplankton community and is also conducting the additional statistical studies as requested by OMSAP. K. Keay added that the Outfall Monitoring Overview is due on November 15th of each year.

T. Smayda asked over what area the 100 cells/L Alexandrium threshold pertains to. M. Liebman replied that it relates to any of the monitoring stations, at any depth. T. Smayda is concerned about the fact that there are pulse introductions of Alexandrium entering Mass Bay related to the run-off of the Maine rivers. The point of entry into Mass Bay is close to the point of nutrient injection [the outfall]. He feels that rather than relying on the introduction and subsequent behavior of an Alexandrium bloom, perhaps information from the north should somehow be considered in the development of a threshold as an early warning. He would like to see this revisited rather than finalized because he is concerned about the practicality of this approach given the kinetics and behavior of the Alexandrium populations. It has been established that even one cell ingested by herring larvae leads to die-off, so while there is the potential for a human impact, there is also the potential for a natural resources impact. M. Liebman agreed that looking at the data from a regional perspective is very important in determining what kind of action would be taken. J. Pederson added that the MADMF receives a pre-warning of Alexandrium blooms from the state of Maine when blooms begin moving down the coast towards Massachusetts.

D. Dow asked if shellfish advisories were observed where they have not been seen before (e.g. east of Sandwich) would there be a study to see if this relates to the outfall pipe. M. Liebman replied that this would be examined and there is another threshold in the Contingency Plan that considers “new incidence” of PSP toxicity.

J. Labonte described background to the floatables threshold and then outlined the requirements in the April 3, 2001 letter to MWRA. EPA/MADEP are requesting that MWRA devise another way to sample floatables and develop a new warning threshold for floatables. She then showed several photographs of floatables collection devices at the Deer Island Treatment Plant. S. Lipman added that the key is to optimize the operations of the plant and to control the floatables throughout the entire treatment system.

L. Schafer asked about the magnitude of the floatables problem. S. Lipman replied that it does not appear to be a significant problem but the tip tube system that collects floatables needs to be improved. N. Jaworski thinks monitoring floatables is important since it is a fairly good indication of an upset or system flushes and thinks the monitoring could be done using a video camera.

D. Dow asked if MWRA will be monitoring for floatables during rainstorms when some flow bypasses secondary. D. Duest replied that all flows come in through the three main pump stations, so all flows pass through the same grit removal and primary treatment facilities where floatables are monitored. B. Berman asked if the net tows for floatables during MWRA surveys in Mass Bay have been capturing much debris because he has not seen very much himself. M. Mickelson replied no, most debris sampled has been broken lobster pots.

M. Liebman explained that one of the main roles of the OMSAP is to advise EPA and MADEP whenever there is a Contingency Plan exceedance. This process needs to operate efficiently in terms of communication and response. There are four responses that depend on the type of exceedance: discuss at next OMSAP meeting, conference call open to public, OMSAP comments independently, or perhaps no discussion needed. C. Coniaris suggested that the OMSAP chair could decide which action OMSAP takes. A. Solow felt uncomfortable having that responsibility on his own. He sees two kinds of notifications: (1) an exceedance that is understood, and a meeting is not needed, and (2) one that is not well understood, at which point OMSAP should discuss over conference call to decide whether or not to meet in person.

B. Berman suggested that the OMSAP staffperson poll the Panel to determine whether a meeting is required.
He thinks it is important to save time by making sure that any written comments go directly to the MWRA and not necessarily through the regulators. M. Liebman said this was a good start and they will work this out further with OMSAP.

D. Duest, manager of process monitoring at the Deer Island Treatment Plant (DITP) described plant performance during the recent extreme wet weather events on March 22 and 30. The DITP normally treats 375 million gallons per day (mgd). On March 21st at 7:00 PM, the plant was operating at 550 mgd and within four hours, flow increased to 1.2 billion gallons a day (bgd). Contaminant loadings to the plant did not change very much, but concentrations actually dropped because of stormwater dilution. Flows averaged 1.136 bgd during the March 22 storm and there was an instantaneous maximum of 1.236 bgd. Secondary battery C was started up on March 8 and there was an average of 456 mgd (~ 40%) of the total flow receiving secondary treatment. All flows were disinfected and dechlorinated. Though the tide levels were three feet above the normal maximum high tide levels, the outfall operated very well. During the March 22 storm, the plant ran 44 hours straight above 1 bgd, with no pump or system failures. During the March 30 storm, the plant ran 18 hours straight over 1 bgd.

C. Hunt asked if the outfall was successful in relieving some of the CSO discharges. D. Duest replied that there was no major flooding on the Boston side. He could not speak for the entire collection system, but there were no major incidents.

S. Nixon was interested in the influence of water level on how much effluent the plant can process and discharge. He wondered what would happen if there was a high inverse barometer effect, higher than the March 22 tides, as well as a very large storm. D. Duest replied that with 1.27 bgd capacity, the plant was running at about 40 feet elevation difference. Additional capacity can be obtained by opening additional ports. To reduce saltwater intrusion into the outfall at low flow conditions, MWRA has not opened all of the ports (271 out of 440 are open now). Low flow defined right now is about 80-120 mgd. One of the problems of saltwater intrusion is that it reduces dilution in the receiving waters. S. Nixon asked if the ports could be opened and closed at the flip of a dial. D. Duest replied no, they have to send divers and it would take several weeks to complete the task. When the outfall is new, there are less frictional losses due to encrusting organisms and thus there is a higher capacity. MWRA is starting to see some limitations in the capacity, and this means that it is time to start thinking about opening up additional ports to maintain the maximum capacity, but we also have to think about the minimum capacity as well. N. Jaworski asked if they have looked ahead to consider what global warming and sea level rise would mean for plant performance. D. Duest replied that this was considered in the long-term design of the facility.

C. Hunt showed SeaWiFS (Sea-viewing Wide Field-of-view Sensor) chlorophyll satellite imagery from NASA of a region-wide phytoplankton bloom that occurred from late August through October 2000. R. Isaac asked what the resolution is on the satellite imagery. C. Hunt replied there is a 1 km pixel. There are three different groups that analyze the satellite data and they vary on how they handle the algorithms and finalize the data. MWRA uses the NASA calculations since they seem very consistent and M. Mickelson can obtain the data quickly. J. Shine pointed out that the satellite only captures the top few meters and cannot capture subsurface maxima.

C. Hunt then showed September chlorophyll satellite data from 1997 to 2000, and it appears that blooms have been becoming more intense. L. Schafer asked if this bloom could be correlated with the outfall start-up. C. Hunt replied no, this is a region-wide bloom from the Gulf of Maine to southern New England, into Long Island Sound. He then showed phytoplankton, in situ fluorescence, particulate organic carbon and nitrogen data, primary productivity, dissolved oxygen, nutrient, and zooplankton data. In situ fluorescence was shown because the chlorophyll extracted data are still under review [see next section].

S. Nixon asked how the satellite data compares with in situ results from the MWRA monitoring program. C. Hunt replied that they are still analyzing the data. He then showed phytoplankton abundance for the entire baseline period. The data show that there has been a fall bloom for five out of the nine baseline years, however, the system generally has similar abundances from year to year. In March 2001, there was a Phaeocystis bloom. The large system-wide bloom began in late August through September and declined as winter approached. D. Dow asked if that was considered to be normal phytoplankton composition. C. Hunt replied that the composition is much like previous years.

A. Solow asked C. Hunt to briefly summarize what they have seen, what is important, and whether this bloom was unexpected. C. Hunt replied that the fall bloom is not unexpected. However, the duration of the high chlorophyll of the regional event and the fact that high chlorophyll values were measured from the surface to the pycnocline were surprising. Typically there is just a subsurface maximum. However, the data are still being evaluated.

N. Jaworski asked if the river flows in the Gulf of Maine were unusual during this time. C. Hunt replied no, Dr. Rocky Geyer has taken a look at that. There does not appear to be anything unusual with the wind, river flows, or temperature profiles. There appeared to be a slightly more rapid cooling between early September and late September, but this is still within the baseline range. There may have been less upwelling because the summer was slightly warmer, but that is also within baseline range.

S. Mayo noted that the southwestern nearfield station had the highest values and asked if there were any other stations with values that high. M. Mickelson replied that it was only one survey that had high levels for the southwestern station. S. Libby added that throughout the entire baseline period, the southwestern nearfield station, N10, had continuously higher chlorophyll levels. This was attributed to the outflow from the harbor, but may also be due to the fact that this is one of the shallower stations that allows for greater nutrient mixing throughout the water column.

S. Nixon noted that most parameters measured seem to be subtlely trending upwards in the last 5-6 years, even in Boston Harbor. C. Hunt agreed but MWRA has not examined this statistically. N. Jaworski pointed out that atmospheric nitrogen deposition has been increasing. C. Hunt added that in mid-1998, secondary treatment began, increasing the amount of ammonia discharged. S. Libby said that one of the sampling stations is right at the harbor outfall, and this may have skewed the harbor averages up.

C. Hunt reviewed the zooplankton data. Lowest numbers were seen in a harbor most likely because there was a major ctenophore (comb jelly) bloom in the harbor ctenophores feed on zooplankton. This ctenophore bloom was also seen in other areas, including Buzzards Bay. He then presented water quality data, all of which was within the ranges observed in the past. S. Mayo asked if these figures will be posted on the web. C. Hunt replied yes, and it will be made clear that this is a work in progress.

J. Schwartz noticed that the ammonia values in the monitoring data seem to be trending upwards. He asked if anyone has looked at the census figures to see if this increase correlates with a population increase in the Boston area. M. Hall replied that MWRA influent nitrogen concentrations have been about the same for the last decade and the effluent nitrogen has decreased (~10%), but the ammonia component of that total nitrogen has increased as a result of secondary treatment and liquids from the Fore River fertilizer pelletizing plant.

B. Berman asked if the zooplankton numbers were still extremely low in Boston Harbor. C. Hunt replied that he did not have the latest zooplankton data from February but guessed that the ctenophores would not survive through the cold weather.

S. Nixon pointed out that there was a significantly higher standing crop of phytoplankton observed in Mass Bay, but not a particularly higher production. He wondered if that was due to less zooplankton grazing and asked if that was seen in the data. C. Hunt replied that they have not looked at this closely yet, but there do not appear to be significantly lower zooplankton numbers.

S. Nixon thought that it was interesting that this does not follow the “textbook story”. It is also interesting to see that this large bloom has not depressed nutrient concentrations significantly. He thinks it will take some time to learn what happened. D. Dow asked there was a relationship between the silicate levels and the spring Phaeocystis bloom. S. Libby replied that the Phaeocystis did not have an effect on the silica levels.

T. Smayda asked how the natural inshore/offshore gradient and north/south gradient could be incorporated into a zooplankton threshold. C. Hunt explained that the low zooplankton in the harbor can be explained by the large ctenophore bloom that grazed on the zooplankton. Changes in the nearfield will be better understood after a full statistical review.

T. Smayda pointed out that this large bloom is an example of an appreciable change/difference. He wondered how this kind of observation may be used to develop some type of threshold. He noted the chlorophyll build-up at the pycnocline, and given the phototaxic ability and the nutrient-gathering migrations that many of the flagellates have, as well as fall mixing that brings nutrients to the surface, he maintains that the outfall has the potential to contribute periodically to significant bloom events, including Alexandrium.

J. Shine asked what made the plume visible on the surface, whether there were microlayers or slicks. M. Mickelson replied that the plume is visible primarily due to physics. Water moves up to the surface, calming the waves coming in. There is no evidence of dissolved organic matter causing any slicks.

S. Nixon thinks the monitoring program will be able to pick up any changes. R. Isaac asked if chlorine would be a better tracer than ammonia. C. Hunt replied that both ammonia and salinity are comparable tracers. They will learn more with the plume tracking.

M. Mickelson described errors in MWRA standard operating procedure for measuring chlorophyll in the laboratory. There are many method to measure chlorophyll, and MWRA measures fluorometrically with acidification. The method involves filtering a known volume of seawater, freezing the filters until they can be analyzed, and then grinding them with 90% acetone and analyzing them on a Turner Designs digital fluorometer. Problems with the data relate to standardization or calibration. The concentration of a sample is based on comparison to a standard, of known concentration. If the lab technician believes the standard is 100 ug/L, and it is only 50 ug/L, then the samples appear to be much higher than they really are. Standards are weighed and exact chlorophyll concentrations are provided by the supplier. Chemical impurities and water can alter the standard concentration, leading to inaccurate data results. MWRA is currently testing new standards with other methods to determine their actual concentrations and the data will be recalculated using these new standards.

S. Nixon asked how they can back-correct for water content in a standard they no longer have. M. Mickelson replied that the standard ampules have a “lot number” of purity. Two lots were used over this time period and there are enough ampules left of one lot that was used for the majority of the program to be able to check for purity. There is also the manufacturer’s statement about purity. Correcting for the older standard will be a bit more problematic, and they are still working this out. A sealed ampule can pick up water through tiny pinholes. The supplier apologized and said that they have had problems trying to control this issue. S. Nixon noted that this means that they are not the only lab to have problems with chlorophyll concentrations.

M. Mickelson said that this investigation was triggered because MWRA’s values were not agreeing with S. Mayo’s and others further north. MWRA calculated chlorophyll values were very high with very large negative phaeophytin values. The sample could also degrade in terms of its fluorescence response. If the acid ratio of the sample is greater than the acid ratio of the standard, there could be a large negative phaeophytin and high chlorophyll values as seen in the data. MWRA is revising its Standard Operating Procedures to outline signs of this problem. This occurred with the 2000 D, E, and F survey samples, and will be corrected.

C. Hunt said that the lab makes standards up every 30 days whereas other labs make a standard and use it for two years. This practice will help in the correction process. The lab also verifies the standard curve using a check standard that is used for an entire year. He is confident that the data can be corrected.

D. Dow asked if there is calibration with the chlorophyll standard both before and after a survey. C. Hunt replied that there is calibration after the survey. N. Jaworski asked how bad the problem is. M. Mickelson replied that the results were overestimated. For the 2000 D, E, and F surveys, it is about 40% higher. This water weight problem produced values that were ~10%-20% higher.

J. Shine asked if the particulate organic carbon is sampled from the same bottle. C. Hunt replied yes. J. Shine suggested looking at carbon to chlorophyll ratio to see if there was anything out of the ordinary. C. Hunt said that that was also one of the things that tipped them off that there was a problem with the chlorophyll data. N. Jaworski asked if they knew how widespread this problem was, since other labs use the same standard. M. Mickelson replied that if they use a spectrophotometer as a back-up, such as URI, they have no problem.

T. Smayda asked if the corrections will take changes of abundances of phytoplankton like that Asterionellopsis vs. microflagellates into consideration. C. Hunt replied that they will go back correct the standard curves and recalculate the data. T. Smayda thinks perhaps it may be better to not correct the error, if corrections involve any guessing.

M. Mickelson described how MWRA plans to calculate the means for the annual chlorophyll threshold. This threshold is based on the mean of the baseline annual means. MWRA is asking OMSAP for a way to calculate this threshold that is more statistically precise, since the year 2000 was not a complete baseline year with the outfall going on-line on September 6, 2000. He described two proposals from MWRA [see MWRA information briefing]. Station mean is calculated by averaging samples from each depth. S. Nixon noted that the samples are not vertically integrated. Integration is a better estimate of what the real water column mean is because the sampling depth intervals are not equal and they change from cruise to cruise. J. Shine did not think vertical integration was difficult to do. T. Smayda agreed with S. Nixon. S. Nixon thinks as long as the depth of the station is known, it can be expressed in per square meter or vertically weighted mean concentration per unit volume. S. Libby said that they did run an integration using the downcast for all the years, using 0.5 m binned averages, and it is relatively simple to do. Survey mean integrated chlorophyll vs. the average show similar patterns.

A. Solow thinks that in this case, it would be better to use averages and not integrate. Integration however, might show some interesting changes at one depth that are offset in the average by changes at another depth that would not be seen using averages. S. Nixon said that it depends on the question being asked and integration can address whether there are some interesting features in the vertical distribution. A. Solow thinks the only problem is that it is possible that there could be changes in the vertical profile that are not examined unless there is a threshold exceedance. He agreed that it depends on what the question is, and if the vertical structure of chlorophyll needs to be monitored for changes, then that hypothesis should be taken into account in the calculation of the threshold.

J. Pederson pointed out that not everyone agrees that threshold numbers have meaning, but they are in the permit. The issue of examining the different depths for changes in chlorophyll is certainly interesting and important right now. This is the kind of topic that Sea Grant can help fund, to look at the data more in-depth.

N. Jaworski thinks integration is a better way of averaging. M. Mickelson pointed out that integration gives future flexibility in the monitoring program, if the number of stations were to increased or reduced. S. Libby stated that the monitoring program samples fewer stations in February, March, April, October, November, and December than we do in the summer because of bad weather. Thus there is biasing to summer conditions, and that is one of the main reasons for using this approach. M. Mickelson repeated what he was hearing from OMSAP, that MWRA try and calculate using integration, allowing for the vertical depths, since it is not that much more difficult. OMSAP agreed.

S. Nixon pointed out that Jack Kelly and others published a model for Mass Bay that could account for the primary production based on light extinction, light, and chlorophyll. If this model continues to hold up, with the high explanation of the variance in the primary production, would MWRA at some point stop measuring primary production and just work with the chlorophyll data. C. Hunt replied that Aimee Keller is still working on that. S. Nixon asked for an update later this year.

M. Mickelson then described the problem in calculating the annual chlorophyll threshold that is based on baseline conditions. The outfall went on-line on September 6, 2000 and thus the year 2000 is not a complete baseline year. He asked OMSAP how to address this problem and suggested that fall 2000 be filled in using an average of the previous baseline years.

N. Jaworski suggested filling in with data from fall 2000 from areas north of the outfall area to take into account the unusual fall bloom. J. Shine said that is introducing a lot of uncertainty. S. Nixon suggested not using the year 2000 data in the threshold calculation. There is plenty of data since more baseline years were collected than initially expected. Why contaminate the threshold number by filling in the fall of 2000 with other data. T. Smayda is frustrated that this has not been worked out sooner. He would not recommend filling in the fall of 2000 with other data, and instead recommended ending the baseline in August 2000. A. Solow disagreed. S. Nixon also disagreed because there is seasonality in the data.

P. Borrelli suggested pushing the data back so that the year ends in the fall for all of the data. The early 1992 data would not be used. S. Nixon agreed to switch the annual cycle to start at day 250. The 1992 data are not thrown away; they exist in the memory and are all part of the analysis. He agreed with J. Shine in that there is going to be a variance in error in that relationship inevitably and the baseline will be contaminated if those numbers are from somewhere else.

A. Solow asked if there were any other proposals on how to aggregate the data. The approach on the table is to shift the seasons and not use the data from the early part of 1992. No one else had any other proposals. N. Jaworski thinks that fall 2000 data need to be incorporated someplace. A. Solow said that when the data are examined in context, it will be noted that there were high chlorophyll values over a large region, not just in the nearfield. M. Mickelson replied that this will be discussed in the annual report data discussion.

ACTION: OMSAP voted to recommend that the chlorophyll baseline for the annual threshold be calculated using a shifted calendar year that begins in September and ends in August. This would take into account the outfall start-up date, September 6, 2000, i.e. the year 2000 was an incomplete baseline year. January to August 1992 data will not be used for the calculation of the annual mean but will be used to calculate the seasonal means.

ACTION: OMSAP approved the November 16, 2000 minutes with no amendments.

M. Hall described test results from the Arbacia punctulata (sea urchin) chronic fertilization test that failed in January 2001. The other three toxicity tests for January passed. He described the test protocols and then discussed what MWRA understands to be the reason why the test failed. The animals are collected in NC and FL via the contract lab since this species is normally distributed from NC to the West Indies. This toxicity test examines the gametes, not the animals themselves. The gametes are obtained by injecting potassium chloride into the animals. The sperm are exposed to the effluent dilutions for one hour and then the eggs are added. After 20 minutes, the samples are preserved and looked at under the microscope to determine the number of fertilized vs. unfertilized eggs per sample. The test evaluates seven dilutions of effluent: 0%, 1.5%, 6.25%, up to 100% effluent. There are four replicates for each of the treatments in the dilution series, and for each of the replicates, 100 eggs are evaluated for fertilization. The test can only be considered valid if 70% of the control eggs are fertilized. Compliance is determined by statistically comparing the various effluent dilutions with the controls.

The NOEC (No Observed Effects Concentration) is the lowest effluent concentration that is not statistically different from the controls. The MWRA threshold requires that the NOEC for this test is 1.5% or greater and is based on worst-case dilution assumptions in the nearfield (100% divided by a dilution of 68, is approximately 1.5%). The January test resulted in an NOEC of less that 1.5%, therefore the results did not meet the permit limit. For the January samples, there were at least 275 separate parameters that were measured along with the toxicity test. The NOEC progressively improved in the February and March samples. The control fertilization, for the January test was relatively low (72.5%), whereas the February control was 79.8%. It is also important to note that the January samples were almost entirely (~95%) secondarily treated, and in general, as the percent secondary decreases, the effluent quality decreases.

M. Hall showed results of chemical analyses of effluent and the results were within safe limits. MWRA believes that two factors played a role in the test failure. First, the animals themselves were probably not in optimal condition for the test. Second, there was a slight increase in chlorine that may have released some of the more bioavailable metals.

M. Hall then explained why it is highly unlikely that there was an impact to the environment. The flow on that day was 339 mgd, low compared to the average and there was no stratification at this time of year, thus dilution was much greater than the worst-case prediction of 68. In addition, there is little biological activity in the area in the middle of January. The Deer Island Treatment Plant now has two autoanalyzers for chlorine in the disinfection basins that will provide more immediate feedback as to the chlorine residuals. Also, the third battery of secondary came on-line in March 2001. Secondary treatment removes the bacteria more effectively, allowing for less chlorination.

S. Nixon did not understand why MWRA is still required in their NPDES permit to conduct monthly toxicity tests. J. Labonte replied that toxicity test results can provide useful information if it tells us that there was something wrong with the effluent. S. Nixon pointed out that the test results correlate inversely with all the other parameters measured. The question is whether the effluent has an impact in the environment, and this is monitored extensively. In addition, MWRA is measuring all of the contaminants in the effluent that would be causes for toxicity. This test has shown at least a 20% variation in just three months on the survivability of the gametes. These are gametes of animals which do not live here, have been transported, and put through a process which members of the scientific community have disagreed with for decades as a way to set toxicity of effluent. He is amazed that EPA still requires toxicity testing.

M. Liebman said that the reason why toxicity is measured in the effluent is because it is impossible to measure toxicity in the field. S. Nixon does not think a result from a toxicity test is an information-rich number, because if an animal dies, nobody knows why because effluent contains many compounds that undergo many reactions. N. Jaworski said that a lot of work went into developing effluent toxicity tests, and they have their place with large effluent discharges. The question is, does MWRA need to run four tests every month.

J. Schwartz asked if pH was measured during the test. M. Hall replied yes, and it was within range. J. Schwartz asked if any polymers were used when the test was conducted. M. Hall replied no.

C. Coniaris explained that the OMSAP charter states that OMSAP will host a public workshop annually to present the monitoring results for the previous year. Planning will begin for the workshops and the PIAC has expressed interest in helping to plan for this meeting and she asked OMSAP to begin thinking about the format of the workshop. J. Pederson suggested having one day of presentations, and then a month later reconvening again for a more in-depth discussion. OMSAP has not been doing this lately since OMSAP has been so tied up with the Contingency Plan thresholds. S. Nixon added that some of the OMSAP meetings could go until 4:00, and we do not necessarily have to meet back to back with PIAC. M. Mickelson asked who the audience would be for these meetings and would it be a science meeting, a public meeting, or something in between. S. Nixon agreed with J. Pederson, in that it would be nice to have some science meetings where we can review the data in depth, and this would not be geared for the public, so it would not be the fall public workshop. The focus of the public workshop seems to be a broader, summary presentation for outside this group. B. Berman thinks it would be great if we could use the fall opportunity to educate the scientific and public policy press on this process.



  • Agenda
  • April 2001 OMSAP/PIAC/IAAC membership lists
  • November 2000 draft OMSAP minutes
  • MWRA information briefings and copies of presentations

Summary prepared by C. Coniaris. Post-meeting comments are included in [brackets]. All such comments have been inserted for clarification only. They do not, nor are they intended to, suggest that such insertions were part of the live meeting components and have been expressly set-off so as to avoid such inference.

Jump to main content.