Sediment-contact and survival of fingernail clams: Implications for conducting short-term laboratory tests

Abstract

ABSTRACT: Porewater toxicity tests have been used as indicators of whole sediment toxicity. However,many species commonly tested in porewater predominately reside in the water column and otherwisehave little to no direct contact with sediment and associated porewater. We assessed the feasibility ofporewater toxicity tests with fingernail clams Musculium transversum , a benthic macroinvertebrate thatinhabits soft bottom sediments and feeds by filtering surface and porewater. Fingernail clams wereexposed to water or sediment in a 96 h laboratory test with a 5=2 factorial experimental design. Thefive treatments included sediments from four sites in the Mississippi River and one sediment-free control()well water . In all treatments, clams were exposed to the sediments or water either directly no(enclosure or indirectly enclosure, suspended above the sediment surface . There were three replicates)( )for each of the ten treatment combinations. Overall, survival of fingernail clams did not vary among thefive treatments ()