Burrowing avoidance assays of contaminated Detroit River sediments, using the freshwater Oligochaete Stylodrilus heringianus (Lumbriculidae)

Abstract

The burrowing behavior of Stylodrilus heringianus (Lumbriculidae, Oligochaeta) was examined in bioassays, using sediments from suspected areas of contamination in the Detroit River, Michigan (U.S.A.). In assays with control sediments and sediments from a clean Detroit River site, all worms quickly burrowed (<1 hr) and appeared to feed normally over a 96-hr period. In sediments with suspected sediment-bound contaminants, Stylodrilus initially burrowed but returned to the surface after a few hours, the time of return apparently dependent on the degree of contamination and length of exposure. The presence of volatile contaminants reduced the initial burrowing response. These observations enhance the possibility of using a Stylodrilus burrowing behavior assay to aid in examining suspected areas of sediment contamination in the Great Lakes.