title: Coastal sediments in the Gulf of Bothnia as a source of dissolved PCDD/Fs and PCBs to water and fish.
abstract: High levels of PCDD/Fs and PCBs in Baltic Sea biota have been a matter of great concern during the last decades. We measured the freely dissolved concentrations of PCDD/Fs and PCBs in sediment pore water and bottom water in eight areas along the Swedish coast of the Gulf of Bothnia, by using state-of-the-art passive samplers. Chemical activity ratios (calculated from freely dissolved concentrations in pore water and bottom water based on chemical activity ratios) for PCDD/Fs were higher than 1 at all stations (PCDD/Fs average 27; stdev 22). High activity ratios suggest that the sediments have a potential to act as a source of dissolved PCDD/Fs to the water column. Activity ratios for PCBs varied between 0.3 and 17 (average 2; stdev 4). The concentrations of PCDD/Fs and PCBs in bottom water were significantly correlated with concentrations in sediment pore water (p<0.00001 to p=0.03) as well as with concentrations in juvenile perch caught in the same areas (p<0.00001 to p=0.02). To our knowledge, this is the first study demonstrating a correlation between in-situ measured freely dissolved PCDD/F concentrations and lipid-normalized contents in stationary fish. Our results confirm that freely dissolved concentrations should be used as chemical predictors of bioaccumulation. The results from this study imply that continued efforts to reduce levels of PCDD/Fs and PCBs in coastal sediments will have positive effects on concentrations of these contaminants in lower trophic levels of Baltic Sea ecosystems.
authors.affiliation: Department of Applied Environmental Science (ITM), Stockholm University, SE-10691 Stockholm, Sweden. Electronic address: anna.sobek@itm.su.se.
authors.forename: A
authors.initials: A
authors.lastname: Sobek
authors.affiliation: Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences (SLU), SE-750 07 Uppsala, Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Wiberg
authors.affiliation: ÅF AB, Umestan Företagspark, SE-903 47 Umeå, Sweden.
authors.forename: K L
authors.initials: KL
authors.lastname: Sundqvist
authors.affiliation: Department of Chemistry, Umeå University, SE-90187 Umeå, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Haglund
authors.affiliation: Department of Applied Environmental Science (ITM), Stockholm University, SE-10691 Stockholm, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Jonsson
authors.affiliation: Department of Applied Environmental Science (ITM), Stockholm University, SE-10691 Stockholm, Sweden; Norwegian Geotechnical Institute (NGI), Oslo, Norway; Department of Plant and Environmental Sciences (IPM), Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway.
authors.forename: G
authors.initials: G
authors.lastname: Cornelissen
mesh_terms: D000818:Animals; D001572:Benzofurans / Q000032:analysis*; D000072338:Dibenzofurans, Polychlorinated; D004784:Environmental Monitoring; D005399:Fishes / Q000378:metabolism; D020387:Food Chain; D019015:Geologic Sediments / Q000737:chemistry*; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D001572:Benzofurans; D000072338:Dibenzofurans, Polychlorinated; D000072317:Polychlorinated Dibenzodioxins; D014874:Water Pollutants, Chemical; D011078:Polychlorinated Biphenyls
keywords: Baltic Sea; Chemical activity ratios; PCBs; PCDD/Fs; Perch; Sediments