In order to assess the importance of the mode of feeding for the bioaccumulation of contaminants from sediments, three marine benthic invertebrates, with different feeding habits, were exposed to contaminated sediments in outdoor mesocosms. Residue analyses were carried out for several polychlorinated biphenyls and polycyclic aromatic hydrocarbons after exposure periods of 60 to 140 days. It was shown that sediment ingestion is a major uptake route for the sediment‐feeding lugworm, Arenicola marina, and for the facultative deposit‐feeding baltic tellin, Macoma balthica. Residues in the filter‐feeding mussel, Mytilus edulis, appeared to be independent of contaminant concentrations in the sediment. The difference between deposit and filter‐feeding bivalves was confirmed in experiments involving the baltic tellin, with differences in the food availability in the overlying water. A simple linear regression model was used to describe contaminant concentrations in sediment‐feeding invertebrates as a function of concentrations in sediment. A correction for the accumulation from water was made by subtracting the concentrations in filter feeders. It was concluded that chemical equilibrium partitioning alone is not sufficient for the assessment of the risks of contaminated sediments to sediment‐feeding invertebrates, but that feeding habits should also be considered.

Abstract-In order to assess the importance of the mode of feeding for the bioaccumulation of contaminants from sediments, three marine benthic invertebrates, with different feeding habits, were exposed to contaminated sediments in outdoor mesocosms. Residue analyses were carried out for several polychlorinated biphenyls and polycyclic aromatic hydrocarbons after exposure periods of 60 to 140 days. It was shown that sediment ingestion is a major uptake route for the sediment-feeding lugworm, Arenicola marina, and for the facultative deposit-feeding baltic tellin, Macoma balthica. Residues in the filter-feeding mussel, Mytilus edulis, appeared to be independent of contaminant concentrations in the sediment. The difference between deposit and filter-feeding bivalves was confirmed in experiments involving the baltic tellin, with differences in the food availability in the overlying water. A simple linear regression model was used to describe contaminant concentrations in sediment-feeding invertebrates as a function of concentrations in sediment. A correction for the accumulation from water was made by subtracting the concentrations in filter feeders. It was concluded that chemical equilibrium partitioning alone is not sufficient for the assessment of the risks of contaminated sediments to sediment-feeding invertebrates, but that feeding habits should also be considered.

A sediment bioassay is being developed using several marine benthic invertebrates to assess the effects of parental transfer of contaminants to the gametes. In this preliminary study, the emphasis was placed on developing methods for the in vitro fertilization of lugworm, Arenicola marina, oocytes.Lugworms exposed to contaminated sediments in outdoor mesocosms were brought to the laboratory, just before the beginning of the spawning period. The reliability of an in vitro fertilization procedure was tested by varying several parts of the method. Main results are that eggs and embryos may be physically damaged by cleaning over a sieve. However, as no negative effects were observed when leaving eggs and sperm together for 24 h, the sperm need not be washed off until the embryos are preserved for further examination later on.A first, incomplete screening of the effects of contaminated harbour dredged sediments indicated some effect on the reproductive success.

No abstract

No abstract