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Acute sensitivity of freshwater mollusks to select chemicals with various toxic modes of action
Citation:
Wang, N., C. Ingersoll, C. Ivey, E. Hammer, C. Bauer, T. Augspurger, Sandy Raimondo, B. Shephard, J. Bartoszek, C. Barnhart, AND N. Eckert. Acute sensitivity of freshwater mollusks to select chemicals with various toxic modes of action. Presented at SETAC North America 33rd Annual Meeting, November 11 - 15, 2012.
Impact/Purpose:
The results of this study can be used by the EPA and FWS to evaluate risks of contaminants to mussels or snails and in development or update of the AWQC, state water quality standards, or permit limits.
Description:
Nearly 70% of the 300 unionid mussel species in North America are endangered, threatened, of special concern, or already extinct. Environmental contamination has been identified as a causal or contributing factor to these declines of mussel populations. Previous studies indicate that mussels are more sensitive to some chemicals, such as copper and ammonia, than commonly tested organisms. However, freshwater mollusks are generally under-represented in toxicity databases. Studies are needed to generate a more comprehensive database to compare the sensitivity of mollusks to other invertebrates, and to evaluate the degree to which existing or proposed US Environmental Protection Agency (EPA) ambient water quality criteria (AWQC) are protective of mollusks relative to Endangered Species Act consultations between EPA and the US Fish and Wildlife Service (FWS). The objectives of this ongoing study are to evaluate sensitivity of select species of mussels and snails, and two commonly tested crustacean species (amphipod, Hyalella azteca, and cladoceran, Ceriodaphnia dubia) in acute (48- to 96-hour) water exposures with 10 selected chemicals in Tier 1 testing, and to “screen” acute sensitivity to additional 10 chemicals with a commonly tested mussel species (fatmucket, Lampsilis siliquoidea) in Tier 2 testing. The mussels for Tier 1 testing were selected to be representative of five tribes of the family Unionidae widely distributed in the Midwest and the Southeast of the US, and the family Margaritiferidae in the Pacific Northwest. Two species of snails to be tested also have a wide geographic distribution in the US. The chemicals selected were chosen based on the AWQC of interest, availability of toxicity data for non-mollusks, other non-unionid mollusks sensitive to the chemical, and different toxic modes of action. Median effect concentrations for each chemical estimated from this study will be compared with those in current national databases for all freshwater