Use of Asiatic Clam Larvae in Aquatic Hazard Evaluations

Investigative efforts to predict the potential impact of single chemical species or mixed effluents on natural waterways emphasize laboratory studies of sensitive nonindigenous aquatic organisms reared under controlled laboratory conditions. Integrated aquatic hazard evaluations appropriately require species representative of a number of trophic levels—algae, invertebrates, and fish—and of different ecological niches—benthic versus pelagic, sessile versus mobile. The oyster embryo toxicity test is often applied in hazard evaluations and is a useful measure of water quality in marine and estuarine environments. Parallel methods have been developed in which freshwater Asiatic clam larvae are used to measure the relative toxicity of industrial chemicals. Two applications, the benthic acute lethality test and the larval transformation toxicity test, are presented. The results compared with other representative aquatic species of fish and invertebrates show that these applications are appropriately sensitive to industrial chemicals. Based on the simplicity and utility of these methods, the author recommends that these and other Asiatic clam monitoring techniques be adopted as tools for assessing the impact of effluents on freshwater aquatic environments.