Resistance of invertebrates to organic contaminants

Evaluation of the toxicity of sediment samples takenfrom the HR Estuary have routinelybeen conducted using native amphipods such as A. abdita collected from Rhode Island (RI) or occasionally a Pacific Coast species. These tests use A. abdita as a surrogate for native species, but the question remains as to whether indigenous amphipods are more tolerant to contaminants in polluted natural environments than the test organisms used. This was addressed when side-by-side tests compared survival between A. abdita collected from RI and from Jamaica Bay (JB) (Serbstetal., 2001). A. abdita from both populations showed good survival in reference sediment but JB amphipods showed lower mortality in JB sediments and contaminated New Bedford Harbor, Massachusetts sediments, suggesting that they had developed resistance.

Much work still needs to be done to understand how invertebrates are responding and adapting to contaminants in their environment. Given the high levels of contamination in parts of the HR Estuary, the well-studied examples of resistance in several fish and one invertebrate species to organic and inorganic contaminants, the HR represents an excellent study site from which to address this issue. This and the study of potential trophic transfer of persistent contaminants from the benthos, through aquatic food chains to top predators and to humans remain important questions that need to be addressed to understand both the risks of these contaminants and the mechanisms of resiliency of indigenous populations.

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