Abstract

A major environmental issue is to understand how eutrophication processes, such as organic enrichment and hypoxia may act on the distribution patterns and bioavailability of contaminants to benthic organisms. An experiment with sediment organic C content (control vs enriched with concentrated phytoplankton) and oxygen level (normoxia vs 2-3 mg O-2 l(-1)) as fixed factors, and C-14-B(a)P in benthic organisms and sediment as dependent variable, was conducted for 93 days. Three species of sediment-dwelling organisms with different feeding strategies (Amphiura filformis, Nereis diversicolor and Abra alba) were chosen. Blue mussels (Mytilus edulis), kept in separate aquaria, were exposed to the outflowing water of the microcosms. Concentration of C-14-B(a)P in the sediment surface at the end of the experiment was significantly higher in the organically enriched sediments than in the control sediments. Accumulation of C-14-B(a)P in A. filformis and N. diversicolor was also higher in the presence of organic enrichment. Concentrations of C-14-B(a)P in M. edulis placed downstream of aquaria treated with organic matter were also higher, indicating a higher leaching of bioavailable C-14-B(a)P from the enriched sediments. Hypoxia had no significant effect on the sediment distribution and bioaccumulation of C-14-B(a)P, and there was no significant interaction between hypoxia and organic enrichment. Our results support the concept of selective feeding on labile organic matter as a major exposure route of organic contaminants in benthic organisms. (C) 1997 Elsevier Science Ltd.

Keywords

organic enrichment; hypoxia; PAH; Amphiura filiformis; Hediste (Nereis) diversicolor; Abra alba; Mytilus edulis; selective feeding

Published in

Marine Pollution Bulletin
1996, volume: 33, number: 1-6, pages: 80-89
Publisher: PERGAMON-ELSEVIER SCIENCE LTD

Authors' information