ASTM E2455-22

SIGNIFICANCE AND USE 5.1 Protection of a species requires prevention of unacceptable effects on the number, weight, health, and uses of the individuals of that species. Toxicity tests can be used provide information about the toxicity of a test material to a specific life stage of a particular species of mussel. The primary adverse effects studied are reduced survival or growth. 5.2 Results of toxicity tests might be used to predict effects likely to occur on mussels in field situations as a result of an exposure under comparable conditions. 5.3 Results of toxicity tests might be used to compare the sensitivities of different mussel species and the toxicity of different test materials, and to study the effects of various environmental factors on results of such tests. 5.4 Results of toxicity tests conducted with mussels might be an important consideration when assessing the risks of test materials to aquatic organisms or when deriving environmental guideline values for toxicants. 5.5 An acute toxicity test is conducted to obtain information concerning the immediate effects on mussels of a short exposure to a test material under specific experimental conditions. An acute toxicity test does not provide information about whether delayed effects will occur, although a post-exposure observation period, with appropriate feeding, if necessary, might provide such information (Guide E729). 5.6 Results of chronic (at least 28 d) toxicity tests with mussels might be used to predict chronic or partial chronic effects on species in field situations as a result of exposure under comparable conditions. 5.7 Short-term chronic toxicity tests are conducted for 7 d, a complementary test duration in the USEPA shot-term methods for estimating the chronic toxicity of effluents and receiving waters to fathead minnow (Pimephales promelas; USEPA 2002) (31) and provides a more direct estimate of the safe concentrations of effluents and receiving waters than acute toxicity tests, at a slightly ... SCOPE 1.1 This standard guide describes methods for conducting laboratory toxicity tests with early life stages of freshwater mussels including glochidia and juvenile mussels in water-only and effluent exposures (Annex A1). Future revisions to this standard may describe methods for conducting toxicity tests with endpoints of reproduction, behaviors, and biomarkers. 1.2 Freshwater mussels (order Unionida) are one of the most imperiled groups of animals in the world, and environmental contamination has been linked as a contributing factor to the decline of mussel populations (Lydeard et al. 2004 (1); Strayer et al. 2004 (2); Haag 2012 (3); Lopes-Lima et al. 2017 (4)).2 Three critical life stages (glochidia, juvenile mussels, and adults) have been used in toxicity assessments and the toxicity studies are separated according to the medium of exposure (water, sediment, and host fish (Ingersoll et al. 2007 (5)). Recent studies on early life stages of mussels have demonstrated that the mussels are among the most sensitive freshwater species to a variety of contaminants, including ammonia, some metals (for example, aluminum, copper, nickel, and zinc), and major ions (for example, chloride, nitrate, potassium, and sulfate) (Bringolf et al. 2007 (6); Newton et al. 2007 (7); Wang et al. 2007ab, 2010, 2011ab, 2016, 2017ab, 2018abc, 2020ab (8-20); Cope et al. 2008 (21); Gillis et al. 2008, 2010, 2011, 2021 (22-25); Miao et al. 2010 (26); Salerno et al. 2020 (27)). These studies indicate that environmental guideline values for individual chemicals established for the protection of aquatic organisms may not be adequately protective of sensitive stages of freshwater mussels. For example, when freshwater mussel toxicity data were included in an update to the United States Environmental Protection Agency (USEPA) ambient water quality criteria (WQC) for ammonia, the acute criterion decreased by about a 1.4 fold and the chronic crite...