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KABAM Version 1.0 User's Guide and Technical Documentation - Appendix C - Explanation of Default Values Representing Biotic Characteristics of Aquatic Ecosystem, Including Food Web Structure

(Kow (based) Aquatic BioAccumulation Model)

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Appendix C. Explanation of Default Values Representing Biotic Characteristics of Aquatic Ecosystem, Including Food Web Structure

The seven trophic levels of the aquatic ecosystem of KABAM are phytoplankton, zooplankton, benthic invertebrates, filter feeders, small fish, medium fish, and large fish. In KABAM, each trophic level is defined by its % lipid, % Non Lipid Organic Matter (NLOM), % water, body weight, and diet. Each of these trophic levels is described within this Appendix, with emphasis on the information relevant to KABAM and explanations of default parameters used to define these trophic levels (in Tables 5 and 6 of the KABAM tool). If the model user wishes to explore the influences of changes in parameter values representing the aquatic food web on EECs and RQs for birds and mammals, this can be accomplished by altering parameter values within the range of reported values for a specific parameter.

Although the % water composition of an aquatic organism does not influence the bioaccumulation of a chemical in that organism (see Appendix A), it is an important consideration for the definition of % lipid and the percent non-lipid organic matter (% NLOM). Often, tissue analysis results and body weight data in the scientific literature are reported on a dry weight basis. For KABAM, input parameters for body composition are entered on a wet weight basis. Therefore, % water composition is discussed in the sections below since it is necessary to understand the water composition of an organism in order to translate the reported data into input parameters for KABAM.

Lipid composition of an organism can influence the bioaccumulation of a chemical (See Appendix A), with higher lipid composition leading to higher accumulation. Since KABAM is intended for use in ecological risk assessments of pesticides with the potential to bioaccumulate in aquatic ecosystems, it is necessary for this tool to serve as a conservative representation of bioaccumulation. Default parameter values for % lipid were selected from the open literature and are intended to represent the high-end of available data (75th-90th percentiles).

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  • C.1 Phytoplankton

    Phytoplankton are microscopic autotrophic aquatic organisms that derive their nutrition from photosynthesis. Groups of freshwater phytoplankton include algae (green, yellow-green and golden-brown), cyanobacteria (blue-green algae), diatoms and dinoflagellates. Phytoplankton can be unicellular, colonial, or filamentous. These organisms have limited mobility that is based on water movements; however, some are able to move via flagella. An aquatic habitat will generally contain an assemblage of phytoplanktonic species that vary in proportion over time and space (Wetzel 1983).

    For parameterization of KABAM, it is necessary to define the % water, % lipid and % NLOM contents of phytoplankton. The body weight is not a necessary input for phytoplankton, nor is the diet composition since these organisms do not consume other organisms.

    Since it is assumed that phytoplankton are present in the water column of the aquatic ecosystem where photosynthesis can occur, it is assumed that phytoplankton do not reside in benthic sediment and do not respire pore water. This should be indicated in Table 5 of the KABAM tool (i.e., "no" should be entered in the column titled: "Do organisms in trophic level respire some pore water?").

    Aquatic plant tissues are composed of approximately 90% water by weight (Hannan and Dorris 1970; Raven et al. 1999, Sladecek and Sladeckova 1963). The default parameter for the water composition of phytoplankton is 90%.

    Reported % lipid values for phytoplankton vary from 2-27% of dry weight. If it is assumed that phytoplankton are composed of 90% water, then this range of lipid compositions is equivalent to 0.2-2.7% on a wet weight basis (Table C1). For KABAM, the default parameter for % lipid of phytoplankton was selected as 2% to represent a high-end estimate (75th to 90th percentile of data in Table C1) of this parameter.

    The wet weight of an organism is the sum of the water, lipid, and NLOM content. If the water content of phytoplankton is 90% of the wet weight, and the % lipid is known (2%), the NLOM content of phytoplankton is the % remaining after subtracting the water and lipid content from 100%. Therefore, the default parameter for the NLOM composition of phytoplankton is 8%.

    Table C1
    Percent Lipid Composition of Freshwater Phytoplankton (under culture conditions)
    Reported in the Scientific Literature
    Species Mean% Lipid (dry weight basis) Mean% Lipid (wet weight basis) Source
    Not stated Not stated 0.5 Oliver and Niimi 1988
    Anabaena sp. 6.8 (± 0.4) 0.68* Stange and Swackhamer 1994
    Anabaena sp. 5.3 (± 2.4) 0.53* Stange and Swackhamer 1994
    Anabaena sp. 2.2 (± 0.2) 0.22* Stange and Swackhamer 1994
    Chamydomonas reinhardtii 10.8 (± 6.2) 1.08* Lürling and Van Donk 1997
    Chlamydomonas applanata 18.2 1.82* Shifrin and Chisholm 1981
    Chlamydomonas applanata 16 1.60* Shifrin and Chisholm 1981
    Chlorella ellipsoidea 13.5 1.35* Shifrin and Chisholm 1981
    Chlorella pyrenoidosa 13.4 1.34* Shifrin and Chisholm 1981
    Chlorella pyrenoidosa 14.4 1.44* Shifrin and Chisholm 1981
    Chlorella pyrenoidosa 16.4 1.64* Shifrin and Chisholm 1981
    Chlorella pyrenoidosa 16 1.60* Shifrin and Chisholm 1981
    Chlorella vulgaris 12.5 1.25* Shifrin and Chisholm 1981
    Chlorella vulgaris 13 1.30* Shifrin and Chisholm 1981
    Cryptomonas pyrenoidifera 8.5 (± 5.1) 0.85* Lürling and Van Donk 1997
    Microcystis aeruginosa 5.8 (± 2.3) 0.58* Lürling and Van Donk 1997
    Nannochloris sp. 20.2 2.02* Shifrin and Chisholm 1981
    Nitzschia palea 22.2 2.22* Shifrin and Chisholm 1981
    Oocystis polymorpha 12.6 1.26* Shifrin and Chisholm 1981
    Ourococcus sp. 27 2.70* Shifrin and Chisholm 1981
    Scenedesmus acutus 6.4 (± 2.5) 0.64* Lürling and Van Donk 1997
    Scenedesmus obliquus 19 1.90* Shifrin and Chisholm 1981
    Selanastrum gracile 20.8 2.08* Shifrin and Chisholm 1981
    Selenasrum capricornutum 19.5 (± 0.2) 1.95* Stange and Swackhamer 1994
    Selenasrum capricornutum 16.0 (± 0.3) 1.60* Stange and Swackhamer 1994
    Selenasrum capricornutum 8.0 (± 0.9) 0.80* Stange and Swackhamer 1994
    Synedra sp. 7.5 (± 1.6) 0.75* Stange and Swackhamer 1994
    Synedra sp. 13.7 (± 0.7) 1.37* Stange and Swackhamer 1994
    Synedra sp. 11.7 (± 4.5) 1.17* Stange and Swackhamer 1994
    Synedra ulna 23 2.30* Shifrin and Chisholm 1981
    Average   1.4  
    75th percentile 1.8
    90th percentile 2.1

    *Calculated from reported % lipid based on dry weight and assumption that algae wet weight is 90% water.

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  • C.2 Zooplankton

    Zooplankton are aquatic animals that are suspended in water. This group is primarily composed of rotifers, cladocera and copepods, but also includes protozoa and insects at immature life stages. Species of zooplankton primarily consume phytoplankton but also consume detritus, bacteria, yeast, and other (smaller) zooplankton (Wetzel 1983). For parameterization of KABAM, zooplankton is represented by herbivorous species that have a diet composed 100% of phytoplankton.

    Since it is assumed that zooplankton are present in the water column of the aquatic ecosystem and do not reside in the benthic sediment, it is assumed that zooplankton do not respire pore water. This should be indicated in Table 5 of the KABAM tool (i.e., "no" should be entered in the column titled: "Do organisms in trophic level respire some pore water?").

    Beers (1966) reported water compositions of several groups of marine zooplankton inhabiting the Atlantic Ocean. Average % water composition of these groups ranged 74-96%, with an average % water composition of 86% corresponding to copepods. Based on this information, the default % water composition of zooplankton is 85%. This value is used to translate dry weight data into equivalent wet weight values.

    Reported mean % lipid values for zooplankton vary from 6.4-24.3% of dry weight. If it is assumed that zooplankton are composed of 85% water, then this range of lipid compositions is equivalent to 0.96-3.6% on a wet weight basis (Table C2). Based on this information, the default % lipid for zooplankton is set to 3% to represent a high-end (75th to 90th percentile) estimate of this parameter.

    The wet weight of an organism is the sum of the water, lipid, and NLOM content. If the water content of zooplankton is 85% of the wet weight, and the % lipid is known (3%), then NLOM content of zooplankton is the % remaining after subtracting the water and lipid content from 100%. Therefore, the default parameter for the NLOM composition of zooplankton is 12%.

    Wright (1958) provided biomass data for two species of zooplankton (Daphnia longispina and D. pulex) in a reservoir in Montana, where the average body weight of zooplankton was 1.3x10-7 kg-wet weight (assuming 85% water content; range 0.9-1.6x10-7 kg-wet weight). Acharya et al. (2005) provided dry body weights for Bosmina freyi that translate to approximately 0.3-3x10-8 kg-wet weight (assuming 85% water content). Jeppesen et al. (2004) provided body weight data for Daphnia sp. that translate to approximately 0.67-3.3x10-7 kg-wet weight (assuming 85% water content). Based on this information, the default weight for zooplankton is set to 1x10-7 kg-wet weight, with the intention of being a representative weight of species of zooplankton.

    Table C2
    Percent Lipid Composition of Freshwater Zooplankton
    Reported in the Scientific Literature
    Zooplankton identification Mean% Lipid (dry weight basis) Mean% Lipid (wet weight basis) Source
    Daphnia magna (cladoceran) 6.4-19.7 0.96-3.0* McKee and Knowles 1987
    Unspecified 6.7* 1.0± 0.33 Morrison et al. 1997
    Mostly cladocerans, also copepods and rotifers 10.8 (± 3.6) 1.6* Mitra et al. 2007
    Mostly cladocerans, also copepods and rotifers 12.1 (± 3.0) 1.8* Mitra et al. 2007
    Mostly cladocerans, also copepods and rotifers 12.2 (± 2.4) 1.8* Mitra et al. 2007
    Leptodora kindtii 13.1 (± 1.0) ** 2.0 Vijverberg and Frank 1976
    Mostly cladocerans, also copepods and rotifers 13.7 (± 1.9) 2.1* Mitra et al. 2007
    Mostly cladocerans, also copepods and rotifers 13.9 (± 1.9) 2.1* Mitra et al. 2007
    Mostly cladocerans, also copepods and rotifers 14.6 (± 1.0) 2.2* Mitra et al. 2007
    Cyclopodia 15.9 (± 1.8)** 2.4 Vijverberg and Frank 1976
    Chydorus sphaericus 18.5 (± 2.8) ** 2.8 Vijverberg and Frank 1976
    Bosmina coregoni 20.5 (± 1.9) ** 3.1 Vijverberg and Frank 1976
    Eurytemora affinus 23.6 (± 2.7) ** 3.5 Vijverberg and Frank 1976
    Daphnia hyalina 24.3 (± 5.3)** 3.6 Vijverberg and Frank 1976
    Average   2.3  
    75th percentile 2.9
    90th percentile 3.3

    *Calculated from reported % lipid based on dry weight and assumption that zooplankton wet weight is 85% water.

    **Expressed as % of total organic matter attributed to lipid. It is assumed that this is equivalent to a dry weight basis.

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  • C.3 Benthic Invertebrates

    The benthic invertebrate trophic level includes animals that inhabit the sediments of aquatic habitats. Benthic invertebrates include a diverse group of animals, including crustaceans (e.g., crayfish, amphipods), aquatic worms (e.g., oligochaetes), aquatic insect larvae (e.g., Diptera, caddisflies, beetles, mayflies and dragonflies), protozoa, snails, and nematodes. Different species of benthic invertebrates have a variety of feeding strategies, including herbiovory, detritivory, and predation upon other benthic invertebrates (Covich et al. 1999). In order to represent all of these feeding strategies with the benthic invertebrate trophic level of KABAM, it is assumed that benthic invertebrates consume organic matter from sediment, phytoplankton, and zooplankton in equal quantities. Therefore, the default diet composition of benthic invertebrates is 34% sediment, 33% phytoplankton, and 33% zooplankton.

    Since it is assumed that benthic invertebrates are present in the benthic compartment of the aquatic ecosystem, it is assumed that benthic invertebrates respire sediment pore water. This should be indicated in Table 5 of the KABAM tool (i.e., "yes" should be entered in the column titled: "Do organisms in trophic level respire some pore water?").

    Available water composition data for benthic invertebrates include a range of 69-83% water (Table C3). The average value of the available data is 76%. Based on this average, the default value for KABAM representing the % water of benthic invertebrates is 76%.

    Table C3
    Water Composition (%) of Benthic Invertebrates
    Reported in the Scientific Literature
    Organism Mean% Water Source
    Crayfish (Orconectus propinquus) 69 Gewurtz et al. 2000
    Hyalella azteca 72.5 Lotufo et al. 2001
    Mayfly larvae 73 Gewurtz et al. 2000
    Diporeia sp. 73.1 Lotufo et al. 2001
    Crayfish (Astacus fluviatilis) 80.0 Sidwell 1981
    Lumbriculus variegatus (oligochaete) 81 Liebig et al. 2005
    Crayfish (Astacus, Orconectus and Procambarus) 82.5* USDA 2005

    *excluding the shell

    Lipid data are available for various freshwater crustaceans, oligochaetes, and insect larvae. These values indicate a wide range (approximately 1 to 10% of wet weight) of lipid composition of benthic invertebrates (Tables C4-C9). The default lipid composition for benthic invertebrates is 3%. This value was selected to be representative of a high-end value (75th percentile) of available lipid compositions for freshwater benthic invertebrates (Table C10).

    Table C4
    Lipid Composition (%) of Hyalella azteca (a freshwater crustacean)
    Reported in the Scientific Literature
    Source Mean% Lipid (dry weight basis) Mean% Lipid (wet weight basis)
    Lotufo et al. 2001 2.4* 0.66 ± 0.03
    Lotufo et al. 2001 3.2* 0.88 ± 0.04
    Lotufo et al. 2001 6.3* 1.73 ± 0.25
    Lotufo et al. 2001 6.5* 1.79 ± 0.41
    Lotufo et al. 2000 6.9 (± 0.9) 1.9*
    Lotufo et al. 2000 7.0 (± 1.1) 1.9*
    Lotufo et al. 2000 7.2 (± 0.8) 2.0*
    Kane Driscoll and Landrum 1997 7.5 (± 1.5) 2.1*
    Lotufo et al. 2000 7.5 (± 0.9) 2.1*
    Lotufo et al. 2000 7.7 (± 1.5) 2.1*
    Kane Driscoll et al. 1997 8.2 (± 0.7) 2.3*
    Kane Driscoll et al. 1997 8.4(± 0.7) 2.3*
    Average 6.6 1.8
    75th percentile 7.6 2.1
    90th percentile 8.2 2.3

    *Calculated from reported % lipid and assumption that dry:wet weight ratio for H. azteca is 0.275 (based on Lotufo et al. 2001).

    Table C5
    Lipid Composition (%) of Freshwater Crayfish (crustaceans)
    Reported in the Scientific Literature
    Genus Mean% Lipid (wet weight basis) Source
    Astacus fluviatilis 0.5 Sidwell 1981
    Orconectus 0.86 (± 0.11) White et al. 1998
    Astacus, Orconectus and Procambarus 1.0 USDA 2005
    Undefined 1.9 (± 0.47) Morrison et al. 1997
    Orconectes propinquus 2.4 (± 0.26) Morrison et al. 2000
    Orconectes 2.52 (± 0.16) Gewurtz et al. 2000
    Procambarus 2.95 (± 1.25) Lin et al. 2004
    Procambarus 3.02 (± 1.29) Lin et al. 2004
    Average 1.9  
    75th percentile 2.6
    90th percentile 3.0
    Table C6
    Lipid Composition (%) of Diporeia sp. (freshwater crustaceans)
    Reported in the Scientific Literature
    Source Mean% Lipid (dry weight basis) Mean% Lipid (wet weight basis)
    Landrum et al. 2007 10.78 (± 1.5) 2.9*
    Landrum et al. 2007 11.97 (± 0.38) 3.2*
    Landrum et al. 2007 17.1 (± 0.64) 4.6*
    Kane Driscoll et al. 1997 20.1 (± 4.6) 5.4*
    Kukkonen et al. 2004 20.4* 5.5 ± 0.7
    Kane Driscoll et al. 1997 21.3 (± 6.7) 5.7*
    Lotufo et al. 2001 22.2* 5.97 ± 0.75
    Kukkonen et al. 2004 23.0* 6.2 ± 1.4
    Lotufo et al. 2001 23.3* 6.27 ± 1.21
    Lotufo et al. 2000 23.7 (± 8.5) 6.4*
    Lotufo et al. 2000 23.9 (± 6.3) 6.4*
    Kane Driscoll and Landrum 1997 27.2 (± 1.3) 7.3*
    Lotufo et al. 2001 40.3* 10.85 ± 0.62
    Lotufo et al. 2001 43.1* 11.59 ± 1.18
    Average 23.5 6.3
    75th percentile 23.9 6.4
    90th percentile 36.4 9.8

    *Calculated from reported % lipid and assumption that dry:wet weight ratio for Diporeia sp. is 0.269 (based on Lotufo et al. 2001).

    Table C7
    Lipid Composition (%) of Lumbriculus variegatus (a freshwater oligochaete)
    Reported in the Scientific Literature
    Source Mean% Lipid (dry weight basis) Mean% Lipid (wet weight basis)
    Croce et al. 2005 5.8* 1.1 ± 0.1
    Kukkonen et al. 2004 6.3* 1.2 ± 0.13
    Liebig et al. 2005 8 (± 0.4) 1.5*
    Kukkonen et al. 2004 7.9 1.5 ± 0.19
    Kukkonen and Landrum 1994 9.2 (± 0.9) 1.7*
    Fisk et al. 1998 10.5* 2.0 ± 0.2
    Kukkonen and Landrum 1994 11.1 (± 1.4) 2.1*
    Fisk et al. 1998 12.1* 2.3 ± 0.2
    Fisk et al. 1998 13.2* 2.5 ± 0.3
    Kukkonen and Landrum 1994 13.2 (± 4.3) 2.5*
    Fisk et al. 1998 15.3* 2.9 ± 0.3
    Fisk et al. 1998 17.9* 3.4 ± 0.8
    Fisk et al. 1998 18.9* 3.6 ± 0.8
    Fisk et al. 1998 19.5* 3.7 ± 0.6
    Average 12.1 2.3
    75th percentile 14.8 2.8
    90th percentile 18.6 3.5

    *Calculated from reported % lipid and assumption that water composition of L. variegatus is 81% (Liebig et al. 2005).

    Table C8
    Lipid Composition (%) of Other Freshwater Oligochaetes
    Reported in the Scientific Literature
    Organism Identification Mean% Lipid (dry weight basis) Mean% Lipid (wet weight basis) Source
    Tubifex tubifex and Limnodrilus hoffmeisteri 5.3* 1* Oliver and Niimi 1988
    Ilyodrilus templetoni** 5.85 (± 2.28) 1.1* Lu et al. 2003
    Ilyodrilus templetoni** 6.11 (± 0.55) 1.2* Lu et al. 2003
    Ilyodrilus templetoni** 6.72 (± 1.59) 1.3* Lu et al. 2003
    Ilyodrilus templetoni** 7.44 (± 1.33) 1.4* Lu et al. 2003
    Ilyodrilus templetoni** 7.35 (± 1.26) 1.4* Lu et al. 2003
    Ilyodrilus templetoni** 8.82 (± 1.60) 1.7* Lu et al. 2003
    Oligochaete 9.5 (± 1.0) 1.8* Landrum et al. 2007
    Limnodrilus sp. 11.93 (± 0.16) 2.3* Jonker et al. 2004
    Oligochaete 12.8 (± 1.8) 2.4* Landrum et al. 2007
    Average 8.2 1.6  
    75th percentile 9.3 1.8
    90th percentile 12.0 2.3

    *Calculated from reported % lipid and assumption that water composition of L. variegatus is 81% (Liebig et al. 2005).

    **Mean of values for I. templetoni is 1.4% (wet weight). When this value is used in calculating the mean and percentile values for the group of oligochaetes, the mean is 1.8% (wet weight). The 75th and 90th percentiles are 2.2 and 2.4, respectively.

    Table C9
    Lipid Composition (%) of Freshwater Insect Larvae
    Reported in the Scientific Literature
    Organism Identification Mean% Lipid (wet weight basis) Source
    Chironomus riparius 0.6 Leonards et al. 1997
    Hexagenia limbata(mayfly larvae) 1.5 (± 0.05) Morrison et al. 2000
    H. limbata and H. rigida 1.50 (± 0.052) Gewurtz et al. 2000
    Caddisfly larvae 1.7 Morrison et al. 1997
    Mayfly larvae 2.0 (± 0.25) Morrison et al. 1997
    Average 1.5  
    75th percentile 1.7
    90th percentile 1.9
    Table C10
    Mean Lipid Composition (%, wet weight basis) of Freshwater Benthic Invertebrates
    from Data in Tables C4-C9.
    Benthic Invertebrate Mean 75th Percentile 90th Percentile
    Insect Larvae 1.5 1.7 1.9
    Hyalella azteca (a freshwater crustacean) 1.8 2.1 2.3
    Freshwater oligochaetes (excluding L. variegatus) 1.8 2.2 2.4
    Crayfish (freshwater crustaceans) 1.9 2.6 3.0
    Lumbriculus variegatus (a freshwater oligochaete) 2.3 2.8 3.5
    Diporeia sp. (freshwater crustaceans) 6.3 6.4 9.8
    Mean 2.6 3.0 3.8

    The wet weight of an organism is the sum of the water, lipid, and NLOM content. By default, if the water content of benthic invertebrates is 76% of the wet weight, and the % lipid is known (default = 3%), the NLOM content of benthic invertebrates is the % remaining after subtracting the water and lipid content from 100%. Therefore, the default parameter for the NLOM composition of benthic invertebrates is 21%.

    The benthic invertebrate trophic level is composed of a wide variety of taxonomic groups. The body weights of organisms within this group can vary by orders of magnitude (Table C11). The default weight for benthic invertebrates is set to 1x10-4 kg-wet weight, with the intention of being representative of a midpoint weight of species of benthic invertebrates.

    Table C11
    Body Weights (wet) of Freshwater Benthic Invertebrates
    Reported in the Scientific Literature
    Benthic Invertebrate Weight (kg) Source
    Amphipods 0.05x10-4 Leonards et al. 1997
    Mayfly larvae 0.16x10-4* Morrison et al. 1997
    Chironomids 0.24x10-4 Leonards et al. 1997
    Caddisfly larvae 0.32x10-4* Morrison et al. 1997
    Snails 0.82x10-4 Leonards et al. 1997
    Crayfish 18.0x10-4 Morrison et al. 1997

    *converted from reported dry weight to wet weight assuming 75% water content.

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  • C.4 Filter Feeders

    Filter feeders are benthic invertebrates that are distinguished by their feeding habits. These organisms feed by straining water and extracting organic material such as detritus and plankton. Examples of freshwater filter feeders include mollusks. For KABAM, it is assumed that filter feeders consume materials suspended in the water column, including phytoplankton, zooplankton, and detritus. It is also assumed that filter feeders consume suspended sediment incidentally. The default composition of the diet of this trophic level is 34% sediment, 33% phytoplankton, and 33% zooplankton.

    Since it is assumed that filter feeders are present in the benthic sediment compartment of the aquatic ecosystem, it is also assumed that filter feeders respire sediment pore water. This should be indicated in Table 5 of the KABAM tool (i.e., "yes" should be entered in the column titled: "Do organisms in trophic level respire some pore water?").

    According to available data, water composition of freshwater mollusks ranges 78-93% (Table C12). The default water content of filter feeders is set to 85%, based on the midpoint of the range of available data.

    Table C12
    Water Composition (%) of Freshwater Mollusks
    Reported in the Scientific Literature
    Identification Mean % water* Source
    Corbicula strata (freshwater clam) 77.6 Sidwell 1981
    Corbicula japonica (freshwater clam) 79.8 Sidwell 1981
    Corbicula sandai (freshwater clam) 80.0 Sidwell 1981
    Corbicula fluminea (freshwater clam) 81.4 Sidwell 1981
    lamellibrancha clams (subclass) 82 USDA 2005
    Corbicula leana (freshwater clam) 82.1 Sidwell 1981
    Dreissena polymorpha (zebra mussel) 87 Bervoets et al. 2005
    D. polymorpha 88-93 Hendriks et al. 1998
    Anodonta anatine (mussels) 90.6-92.8 Hyötyläinen et al. 2002

    *It is assumed that this does not include the shell.

    Data on lipid content are available for several species of freshwater mollusks. These values range 0.4-4% of wet weight (Tables C13 - C15). The default lipid composition for filter feeders is 2%. This value was selected to be representative of a high end (75th percentile of Dreissena sp. and Corbicula sp.) value of available lipid compositions for freshwater mollusks.

    Table C13
    Percent Lipid Composition of Dreissena sp. (freshwater mollusks)
    Reported in the Scientific Literature
    Species Mean % Lipid (dry weight basis) Mean % Lipid (wet weight basis) Source
    D. polymorpha 4.3* 0.55 Bervoets et al. 2005
    D. polymorpha 14 1 Hendriks et al. 1998
    D. polymorpha 8.5* 1.1 Kwon et al. 2006
    D. polymorpha 9.1 1.2* Becker van Slooten and Tarradellas 1994
    D. bugensis 9.0 (± 1.4) 1.2* Marvin et al. 2002
    D. bugensis 10 (± 0.5) 1.3 Marvin et al. 2002
    D. polymorpha 11 (± 0.6) 1.4* Marvin et al. 2002
    D. polymorpha 10.8* 1.4 (± 0.1) Kwon et al. 2006
    D. polymorpha 11.5* 1.5 (± 0.1) Kwon et al. 2006
    D. polymorpha 12.3* 1.6 (± 0.1) Kwon et al. 2006
    D. polymorpha 12 (± 4.4) 1.6* Marvin et al. 2002
    D. polymorpha 17 2 Hendriks et al. 1998
    D. polymorpha 18 2 Hendriks et al. 1998
    Average 11.3 1.4  
    75th percentile 12.3 1.6
    90th percentile 16.4 1.9

    * Calculated from reported % lipid and assumption that water composition of D. polymorpha is 87% (Bervoets et al. 2005).

    Table C14
    Percent Lipid Composition of Corbicula sp. (freshwater clams)
    Reported in the Scientific Literature
    Species Mean % Lipid (wet weight basis) Source
    C. leana 1.1 Sidwell 1981
    C. japonica 1.2* Kang et al. 2002
    C. japonica 1.2 Sidwell 1981
    C. fluminea 1.5 Sidwell 1981
    C. sandai 2.4 Sidwell 1981
    C. strata 4.0 Sidwell 1981
    Average 1.9  
    75th percentile 2.2
    90th percentile 3.2

    *Based on reported mean lipid content of 5.8% dry weight and 80% moisture content reported for this species by Sidwell 1981.

    Table C15
    Percent Lipid Composition of Other Freshwater Filter Feeders
    Reported in the Scientific Literature
    Identification Mean % Lipid (dry weight basis) Mean % Lipid (wet weight basis) Source
    Sphaerium striantium (fingernail clam) 8.7 0.36 Rice and White 1987
    Elliptio complanata 3.2 (± 1.2) 0.48* Marvin et al. 2002
    Anodonta anatine (mussels) 11.2 (± 0.8) 0.81 Hyötyläinen et al. 2002
    Anodonta anatine (mussels) 12.2 (± 0.7) 0.98 Hyötyläinen et al. 2002
    Lamellibrancha (clams) 5.5 1.0 USDA 2005
    Anodonta anatine (mussels) 10.9 (± 0.6) 1.02 Hyötyläinen et al. 2002
    Anodonta anatine (mussels) 11.3 (± 0.9) 1.05 Hyötyläinen et al. 2002

    *Calculated using assumption that filter feeders are 85% water.

    The wet weight of an organism is the sum of the water, lipid, and NLOM content. By default, if the water content of filter feeders is 85% of the wet weight and the % lipid is known (default = 2%), the NLOM content of filter feeders is the % remaining after subtracting the water and lipid content from 100%. Therefore, the default parameter for the NLOM composition of filter feeders is 13%.

    Reported wet weights of various species of mollusks range 0.2-12 x10-3 kg. Mean wet weights of Dreissena polymorpha have been reported as 0.41 ± 0.26 x10-3 kg (Van Haelst et al. 1996). Wet weights of C. fluminea ranged approximately 0.2-2 x10-3 kg (Andrès et al. 1999, Vidal et al. 2002). Hyötyläinen et al. (2002) reported wet weights of Anodonta anatine tissue as ranging 4.5-12.1 x10-3 kg. Based on this information, the default weight of filter feeders is set to 1 x10-3 kg, with the intention of being a representative weight of mollusks.

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  • C.5 Fish (Small, Medium and Large Sizes)

    There are hundreds of species of fish inhabiting fresh waters of the United States and Canada, including ponds, lakes, streams, and rivers. Species of bluegill and other sunfish (Lepomis spp.), bass (Micropterus spp.), and crappie (Pomoxis spp.) are common inhabitants of fresh warm water ponds, lakes, and streams distributed throughout the continental United States (Page and Burr 1991, Carlander 1977). As described below, these species were used to define default parameters for the small, medium, and large fish in KABAM. Although there are many other species of fish in ponds of the U.S. (e.g., perch, minnows), sunfish, crappie, and bass were considered representative of fish that are found in freshwaters of the U.S., and thus suitable for models for defining input parameters for use in KABAM.

    Several bird and mammal species (e.g., belted kingfisher [Megaceryle alcyon], northern river otter) consume amphibians, in addition to fish. For KABAM, it is assumed that the default fish also represent, i.e., serve as surrogates for, aquatic-phase amphibians, such as salamanders and frogs. This assumption is consistent with OPP's policy in which exposure and effects data for fish are assumed to be representative of aquatic-phase amphibians (USEPA 2004).

    Default parameters for small fish in KABAM are designed to represent the young-of-year (YOY), i.e., fish that have hatched within the year, before January 1 of the next year, of sunfish, bass and crappie. YOY of these species consume copepods, cladocerans, rotifers (i.e., zooplankton), chironomid larvae, and mayfly larvae (i.e., benthic invertebrates) (Carlander 1977). Average body weights of YOY of sunfish, bass, and crappie are provided in Table C16. For KABAM, it is assumed that the small fish weighs 0.01 kg and its diet is 50% zooplankton and 50% benthic invertebrates.

    Table C16
    Average Body Weights for Young of the Year Fish
    (Source: Carlander 1977)
    Species (scientific name) Average body weight (kg)
    Green sunfish (Lepomis cyanellus) 0.001-0.01
    Pumpkinseed (L. gibbosus) 0.002
    Warmouth (L. gulosus) < 0.011
    Bluegill (L. macrochirus) 0.0001-0.05
    Redear sunfish (L. microlophus) 0.0006-0.04
    Largemouth bass (Micropterus salmoides) 0.0002-0.02
    White crappie (Pomoxis annularis) 0.0002-0.01
    Black crappie (P. nigromaculatus) 0.0005-0.02

    The medium fish in KABAM is designed to represent adult sunfish and crappie. These fish reach sexual maturity between ages 1 and 3, with lifespans ≥ 6 years. Their diets include insects, insect larvae, crustaceans, snails, and other fish (Carlander 1977). Mature fish range in weight, 0.005-0.579 kg, depending upon their age (Table C17; data from Carlander 1977). Although mature fish display a wide range of weights, most species weigh approximately 0.1 kg as adults. For KABAM, it is assumed that the medium-sized fish weighs 0.1 kg and its diet is 50% benthic invertebrates and 50% small fish.

    Table C17
    Average Body Weights (in kg) of Medium Fish at Different Ages
    Species (scientific name) 1 yr 2 yr 3 yr 4 yr 5 yr 6 yr 7 yr 8 yr
    Green sunfish (Lepomis cyanellus) 0.01 0.024 0.048 0.086 0.086 0.132 - -
    Pumpkinseed (L. gibbosus) 0.005 0.034 0.034 0.063 0.099 0.157 0.157 0.157
    Warmouth (L. gulosus) 0.011 0.046 0.046 0.085 0.163 0.163 - -
    Bluegill (L. macrochirus) 0.014 0.052 0.052 0.090 0.141 0.141 0.208 0.208
    Redear sunfish (L. microlophus) 0.026 0.081 0.125 0.187 0.187 0.265 - -
    White crappie (Pomoxis annularis) 0.031 0.085 0.123 0.181 0.346 0.346 0.579 0.579
    Black crappie (P. nigromaculatus) 0.037 0.097 0.143 0.210 0.289 0.363 0.468 0.468

    - Indicates data were not available

    The large fish in KABAM is designed to represent the largemouth bass (Micropterus salmoides), which is a predatory fish commonly found in warm waters throughout the continental United States. It is also designed to be representative of large predatory fish that are consumed by mammals and birds. The diet of largemouth bass is composed primarily of fish, including sunfish, crappie, perch, shad and smaller-sized largemouth bass. Largemouth bass will also consume crayfish, especially when no other fish are available. Largemouth bass become sexually mature between ages 2-5, with a lifespan reaching beyond 10 years. Adult largemouth bass weigh 0.25-3.6 kg, depending upon their age (Carlander 1977). For KABAM, it is assumed that the large fish weighs 1 kg, and consumes 100% medium-sized fish.

    Since small and medium fish consume benthic invertebrates, it is assumed that these fish are sometimes present in the benthic compartment of the aquatic ecosystem. Therefore, it is assumed that small and medium fish respire some pore water. It is assumed that medium fish are predominantly present in the water column of the aquatic ecosystem, where they are consumed by large fish. It is assumed that large fish do not respire pore water. This should be indicated in Table 5 of the KABAM tool (i.e., "yes" should be entered for small and medium fish and "no" should be entered for large fish in the column titled: "Do organisms in trophic level respire some pore water?").

    Available water composition data for Lepomis sp., Pomoxis sp., and Micropterus sp. include a range of 71-80% water (Table C18). Although water composition data were not available for largemouth bass, data do exist for smallmouth bass (M. dolomieu) and are used as a surrogate for largemouth bass. The average value of the available data is 73%. Based on this average, the default value for KABAM representing the % water of all fish is 73%.

    Table C18
    Water Composition Data for Fish Relevant to Small, Medium, and Large Default Fish of KABAM
    Species (scientific name) Reported Body Weight (kg) Corresponding Default fish % water Source
    Black crappie (Pomoxis nigromaculatus) 0.102 (± 0.007) Medium 70.7 (± 0.29) Sethajintanin et al. 2004
    Smallmouth bass (Micropterus dolomieu) 0.277 (± 0.0901) Medium-Large 71.1 (± 1.26) Sethajintanin et al. 2004
    Smallmouth bass (Micropterus dolomieu) 0.870 (± 0.0685) Medium-Large 71.3 (± 1.76) Sethajintanin et al. 2004
    Smallmouth bass (Micropterus dolomieu) 0.326 (± 0.177) Medium-Large 71.9 (± 1.44) Sethajintanin et al. 2004
    Black crappie (Pomoxis nigromaculatus) 0.148 (± 0.021) Medium 71.9 (± 0.84) Sethajintanin et al. 2004
    Smallmouth bass (Micropterus dolomieu) 0.395 (± 0.222) Medium-Large 72.0 (± 0.99) Sethajintanin et al. 2004
    Black crappie (Pomoxis nigromaculatus) 0.114 (± 0.016) Medium 72.1 (± 0.87) Sethajintanin et al. 2004
    Black crappie (Pomoxis nigromaculatus) 0.111 (± 0.015) Medium 72.6 (± 0.38) Sethajintanin et al. 2004
    Black crappie (Pomoxis nigromaculatus) 0.0798 (± 0.012) Medium 73.2 (± 0.59) Sethajintanin et al. 2004
    Smallmouth bass (Micropterus dolomieu) 0.154 (± 0.0647) Medium 73.4 (± 2.11) Sethajintanin et al. 2004
    Bluegill (L. macrochirus) Not reported unknown 79.5 Sidwell 1981

    Lipid content of fish reported in the literature varies widely for Lepomis sp., Pomoxis sp., and Micropterus sp. from 0.5-8% on a wet weight basis, with an average value of 2.9% and a 75th percentile of 4.0% (Table C19). Table C19 includes lipid composition data for wild-caught and laboratory-reared Lepomis sp., Pomoxis sp., and Micropterus sp. Several lipid content values available in the literature cannot be related to the weights of the fish analyzed due to a lack of information included in the individual studies. Thus, these lipid contents cannot be related to one of KABAM's default fish. Based on this and the data in Table C19, the default lipid composition for all three fish is set to 4%, to be representative of a high-end value.

    Table C19
    Lipid Composition Data for Fish Relevant to Small, Medium, and Large Default Fish of KABAM
    Species
    (scientific name)
    Reported Body Weight (kg) Corresponding Default fish % Lipid
    (wet weight)
    Source
    Green sunfish
    (Lepomis cyanellus)
    Not reported Unknown 0.5-2 Price and Birge 2006
    Bluegill
    (L. macrochirus)
    0.012 (± 0.0012) Small 0.72 (± 0.46) Liber et al. 1999
    Largemouth bass
    (Micropterus salmoides)
    Not reported Small (defined based on length data) 0.89 (± 0.19)* Miranda and Hubbard 1994
    Largemouth bass
    (Micropterus salmoides)
    Not reported Small (defined based on length data) 0.95(± 0.26)* Miranda and Hubbard 1994
    Largemouth bass
    (Micropterus salmoides)
    Not reported Small (defined based on length data) 0.97 (± 0.18)* Miranda and Hubbard 1994
    White crappie
    (Pomoxis annularis)
    Not Reported Assume medium (spawning fish) 1 Neuman and Murphy 1992
    Longear sunfish
    (L. megalotis)
    Not reported Unknown 1-2 Price and Birge 2006
    Bluegill
    (L. macrochirus)
    Not reported Unknown 1-3 Price and Birge 2006
    Largemouth bass
    (Micropterus salmoides)
    Not reported Unknown 1-5 Price and Birge 2006
    Largemouth bass
    (Micropterus salmoides)
    Not reported Small (defined based on length data) 1.3 (± 0.29)* Miranda and Hubbard 1994
    Largemouth bass
    (Micropterus salmoides)
    Not reported Small (defined based on length data) 1.3 (± 0.24)* Miranda and Hubbard 1994
    Largemouth bass
    (Micropterus salmoides)
    Not reported Small (defined based on length data) 1.6 (± 0.47)* Miranda and Hubbard 1994
    Bluegill
    (L. macrochirus)
    Not reported (juveniles) Presume small 1.7* Fischer et al. 1998
    Bluegill
    (L. macrochirus)
    Not reported (adult males) Presume medium 1.8* Fischer et al. 1998
    Smallmouth bass
    (Micropterus dolomieu)
    Not reported Unknown 1.90 Kay et al. 2005
    White crappie
    (Pomoxis annularis)
    Not Reported Assume medium (spawning fish) 2 Neuman and Murphy 1992
    Bluegill
    (L. macrochirus)
    Not reported (adult females) Presume medium 2.1* Fischer et al. 1998
    Black crappie
    (Pomoxis nigromaculatus)
    0.114 (± 0.016) Medium 2.19 (± 0.51) Sethajintanin et al. 2004
    Bluegill
    (L. macrochirus)
    Not reported Unknown 2.3 Sidwell 1981
    Black crappie
    (Pomoxis nigromaculatus)
    0.111 (± 0.015) Medium 2.54 (± 1.85) Sethajintanin et al. 2004
    Smallmouth bass
    (Micropterus dolomieu)
    Not reported Unknown 2.70 Kay et al. 2005
    Black crappie
    (Pomoxis nigromaculatus)
    0.148 (± 0.021) Medium 2.82 (± 0.36) Sethajintanin et al. 2004
    White crappie
    (Pomoxis annularis)
    Not Reported Assume medium (spawning fish) 3 Neuman and Murphy 1992
    Smallmouth bass
    (Micropterus dolomieu)
    0.395 (± 0.222) Medium-Large 3.09 (± 1.08) Sethajintanin et al. 2004
    Black crappie
    (Pomoxis nigromaculatus)
    0.0798 (± 0.012) Medium 3.11 (± 1.63) Sethajintanin et al. 2004
    Black crappie
    (Pomoxis nigromaculatus)
    0.102 (± 0.007) Medium 3.15 (± 0.40) Sethajintanin et al. 2004
    Smallmouth bass
    (Micropterus dolomieu)
    Not reported Medium-Large (defined based on length data) 3.3 (± 0.3) Kwon et al. 2006
    Smallmouth bass
    (Micropterus dolomieu)
    0.154 (± 0.0647) Medium 3.33 (± 1.8) Sethajintanin et al. 2004
    Smallmouth bass
    (Micropterus dolomieu)
    0.326 (± 0.177) Medium-Large 4.17 (± 1.34) Sethajintanin et al. 2004
    Smallmouth bass
    (Micropterus dolomieu)
    0.870 (± 0.0685) Medium-Large 4.93 (± 0.33) Sethajintanin et al. 2004
    White crappie
    (Pomoxis annularis)
    Not Reported Assume medium (spawning fish) 5 Neuman and Murphy 1992
    White crappie
    (Pomoxis annularis)
    Not Reported Assume medium (spawning fish) 5 Neuman and Murphy 1992
    Smallmouth bass
    (Micropterus dolomieu)
    0.277 (± 0.0901) Medium-Large 5.03 (± 0.358) Sethajintanin et al. 2004
    Smallmouth bass
    (Micropterus dolomieu)
    Not reported Medium-Large (defined based on length data) 5.5 (± 0.4) Kwon et al. 2006
    Smallmouth bass
    (Micropterus dolomieu)
    Not reported Medium-Large (defined based on length data) 5.6 (± 0.2) Kwon et al. 2006
    Smallmouth bass
    (Micropterus dolomieu)
    Not reported Medium-Large (defined based on length data) 5.8 (± 0.4) Kwon et al. 2006
    White crappie
    (Pomoxis annularis)
    Not Reported Assume medium (spawning fish) 6 Neuman and Murphy 1992
    Bluegill
    (L. macrochirus)
    0.00972 (± 0.00276) Small 7.9 (± 0.14) Carr et al. 1997
      Average 2.9  
      75th percentile 4.0  
      90th percentile 5.5  

    *Calculated from reported dry weight assuming that fish = 73% water (Table C18).

    The wet weight of an organism is the sum of the water, lipid, and NLOM content. By default, if the water content of fish is 73% of the wet weight, and the % lipid is known (default = 4%), the NLOM content of fish is the % remaining after subtracting the water and lipid content from 100%. Therefore, the default parameter for NLOM composition is 23%.

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