Testing Sediment Toxicity with Hyalella azteca (Amphipoda) and Chironomus riparius (Diptera)

Methods for testing the toxicity of whole sediments are described for the amphipod Hyalella azteca and the midge Chironomus riparius. Amphipod tests (static and flow-through) start with juvenile animals (≤ third instar) and continue up to 29 d until reproductive maturation. Flow-through tests with the midge start with first instar larvae (<24 h old) and continue up to 29 d through adult emergence. Data obtained from these laboratory exposures can be used to assess the effects of contaminants in sediments on survival, growth, or emergence of amphipods and midges. The methods were used to assess the potential toxicity of field-collected contaminated sediment from two sites in Waukegan Harbor, Illinois, an inlet of Lake Michigan contaminated with polychlorinated biphenyls (PCBs), polycyclic aromatic compounds (PACs), and metals; and a single site at Homer Lake, a small recreational lake in the agricultural region of central Illinois. Survival of both species was reduced after short-term (10-to 13-d) and long-term (29-d) exposure to contaminated sediment. In addition, sublethal effects were indicated by reduced growth of amphipods and a delay in emergence of adult midges.