title: Biological and chemical determination of dioxin-like compounds in sediments by means of a sediment triad approach in the catchment area of the river Neckar.
abstract: To evaluate the sediment quality of selected sites in the catchment area of the River Neckar, an integrative assessment approach was used to assess the ecological hazard potential of dioxin-like sediment compounds. The approach is based on 7-ethoxyresorufin-O-deethylase (EROD) induction in embryonic chicken liver culture and comprehensive chemical analyses of polycyclic aromatic hydrocarbons (priority PAHs according to the US Environmental Protection Agency). The majority of the sediment extracts exhibited high potencies as EROD-inducers. In one sediment sample, which was influenced by a sewage treatment plant, a very high concentration of 930 ng bioassay 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents (bio-TEQs )/g organic carbon could be determined. However, in none of the samples, more than 6% of the EROD-inducing potency could be explained by the PAHs analyzed chemically. Thus, non-analyzed compounds with EROD-inducing potency were present in the extracts. A fractionation of sediment samples according to pH allowed to localize the major part of EROD-inducing compounds in the neutral fractions. However, a significant portion of the EROD induction could also be explained by the acidic fractions. Following the concept of the Sediment Quality Triad according to Chapman, in situ alterations of macrozoobenthos were examined. A comparison of the results predicted by the EROD assay and chemical analyses with alterations in situ, as measured by means of the saprobic index and the ecotoxicological index according to Carmargo, revealed a high ecological relevance of the results of bioassays and chemical analyses for major sites.
authors.affiliation: Department of Zoology, University of Heidelberg, Germany. henner.hollert@urz.uni-heidelberg.de
authors.forename: Ner
authors.initials: N
authors.lastname: Hollert
authors.forename: Matthias
authors.initials: M
authors.lastname: Dürr
authors.forename: Helena
authors.initials: H
authors.lastname: Olsman
authors.forename: Krister
authors.initials: K
authors.lastname: Halldin
authors.forename: E
authors.initials: E
authors.lastname: van Bavel
authors.forename: Werner
authors.initials: W
authors.lastname: Brack
authors.forename: Mats
authors.initials: M
authors.lastname: Tysklind
authors.forename: Magnus
authors.initials: M
authors.lastname: Engwall
authors.forename: Thomas
authors.initials: T
authors.lastname: Braunbeck
mesh_terms: D000818:Animals; D002642:Chick Embryo; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism; D004147:Dioxins / Q000032:analysis* / Q000633:toxicity; D004784:Environmental Monitoring / Q000379:methods; D005618:Fresh Water; D019015:Geologic Sediments / Q000032:analysis*; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis* / Q000633:toxicity; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity
chemical_list: D004147:Dioxins; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical; D019363:Cytochrome P-450 CYP1A1