Sediment bioaccumulation test with upper Mississippi River sediments using the oligochaete Lumbriculus variegatus

The test is part of the U.S.G.S. investigation Flood Effects on Surficial Bed Sediments Stored in the Navigational Pools of the Upper Mississippi River. In the laboratory Lumbriculus variegatus were exposed 28 days to sediments collected from 13 upper Mississippi River stations. The laboratory exposure was conducted using guidelines published in USEPA Methods for Measuring the Toxicity and Bioaccumulation of Sediment associated Contaminants with Freshwater Invertebrates. For comparison to laboratory results, native oligochaetes were isolated in the field from subsamples of each of the 13 sediments. Both laboratory exposed and field collected oligochaetes were allowed to clear their gut contents for 24 hours after sampling. After elimination, the oligochaete samples were stored frozen until analyzed. Organic contaminants were measured in the both sets of oligochaetes and the concentrations were compared. In general the concentrations of contaminants in both laboratory an field-collected oligochaetes were low. For many of the compounds measured, there was good agreement between laboratory exposed and field collected oligochaetes.