Bioaccumulation of PCBs from Sediments by Oligochaetes and Fishes: Comparison of Laboratory and Field Studies

Abstract

Fathead minnows (Pimephales promelas) and oligochaetes (Lumbriculus variegatus) were exposed in the laboratory to sediment samples from the lower Fox River/Green Bay, and their bioaccumulation of PCBs was compared with PCB concentrations in synoptic collections of fish (black bullhead, Ameiurus melas) and oligochaetes (primarily Limnodrilus sp.) from the field. Total PCBs and PCB homologues (expressed as lipid-normalized tissue concentrations/organic carbon-normalized sediment concentrations) were qualitatively and quantitatively similar in the laboratory-exposed and field-collected oligochaetes. PCB concentrations in A. melas generally were greater than in any of the other test species, due possibly to differences in exposure (e.g. biomagnification) compared with the other organisms. PCB concentrations in P. promelas were consistently smaller than in any of the other species investigated. These results indicate that, under the exposure regime used in this study, laboratory tests with L. variegatus can provide a reasonable quantitative estimate of the bioaccumulation of PCBs in field populations of oligochaetes. However, the use of P. promelas in laboratory sediment tests may result in significant underprediction of the exposure of indigenous benthic invertebrates and fishes to bioaccumulable contaminants.