Short-term lethality and sediment avoidance assays with endrin-contaminated sediment and two oligochaetes from Lake Michigan

Abstract

Mean 96-hr LC 50 values and standard deviations for the oligochaetes S. heringianus and L. hoffmeisteri exposed to endrin-contaminated sediment were 2,588±1,974 μg/g dry weight sediment for 4 assays and 2,725±955 μg/g for 2 assays, respectively. Mixed species testing data suggested that the toxicity to L. hoffmeisteri was reduced in the presence of S. heringianus , yet further testing is required. Ninety-six hour EC 50 burrowing avoidance values for both species (19 and 15.3 μg/g for S. heringianus and 59 μg/g for L. hoffmeisteri ) were approximately 46 and 150 times lower than their respective mean 96-hr LC 50 values. Both S. heringianus and L. hoffmeisteri initially burrowed in contaminated sediment and then returned to the surface in numbers somewhat proportional to the sediment concentration and the length of exposure. Future use of oligochaete behavioral responses to subiethal sediment contamination for pollutant impact on benthic communities is promising.