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. (C) 2014 Elsevier B.V. All rights reserved.

Keywords

PCDD/Fs; Sediments; Chemical activity ratios; Perch; PCBs; Baltic Sea

Published in

Science of the Total Environment
2014, volume: 487, pages: 463-470
Publisher: ELSEVIER SCIENCE BV

SLU Authors

• Wiberg, Karin

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

Global goals (SDG)

SDG6 Clean water and sanitation
SDG14 Life below water

UKÄ Subject classification

Oceanography, Hydrology, Water Resources
Environmental Sciences

Publication identifier

• DOI: https://doi.org/10.1016/j.scitotenv.2014.04.041

Permanent link to this page (URI)

https://res.slu.se/id/publ/67186