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3F - Coastal Zone Mgnt (WEP/179) Do sediment assessment criteria based on biological effects need adaptation for estuarine environments? van den Heuvel-Greve, Martine1, Dubbeldam, Marco2, Hannewijk, André1, Postma, Jaap2, Vethaak, Dick1, 1 RIKZ, Kamperland, the Netherlands, the Netherlands2 AquaSense BV, Colijnsplaat, the Netherlands, the Netherlands ABSTRACT- An integrated chemical-biological tool to assess sediment quality will be implemented into Dutch policy in 2006. For this purpose bioassays need to be developed, standardized and validated for marine and estuarine environments. Estuaries are key areas to monitor since contaminants tend to accumulate here and changes in salinity may influence both bioavailability of compounds and physiological responses of organisms to contaminants. Do existing biological assessment criteria (such as mortality) for marine sediments need adaptation for estuaries? We tested the physiological response of the amphipod Corophium volutator to different salinities when exposed to contaminants, in a whole sediment in vivo bioassay. C. volutator is a benthic organism that prefers brackish water (10-35 ppt), but can survive in 5 ppt. Sediment was spiked with either lindane or fluoranthene. These contaminants were chosen because it is known that the characteristics of both compounds are not influenced by salinity. The salinity of the overlying water was 5-10-15-30 ppt. Mortality of the amphipod was determined after 10 days. In addition, surviving C. volutator in the fluoranthene test system were exposed to UV-light to determine bioaccumulation of the compound. We observed no significant differences in response between 10, 15 and 30 ppt, and only a minimal increase in susceptibility of C. volutator in 5-ptt seawater. The results support the use of C. volutator for assessing sediment quality in estuaries with salinities ranging from 5-30 ppt. No adaptation of the biological evaluation methodology seems necessary for this bioassay. Future studies will determine whether adaptation of biological assessment criteria for other organisms (e.g. Nereis diversicolor) is necessary for the estuarine environment. Key words: sediment, estuaries, bioassay, Corophium volutator |
