Baltic Sea sediment records: unlikely near-future declines in PCBs and HCB.
We present a comprehensive study on PCBs and HCB in dated sediment cores from the Baltic Sea covering the 20th century, and compare their spatiotemporal trends with those of PCDD/Fs from the same areas. PCB concentrations in coastal impacted sediment followed the temporal trend of estimated global emissions of PCBs and thus responded quickly to changes in global industrial use, whereas concentrations in offshore sediment needed 10-20 years longer to respond. Differences in spatiotemporal trends of PCDD/Fs and PCBs were smaller than expected based on documented differences in key sources and source areas. Sediment concentrations of HCB varied little over time and space, but concentrations are increasing in recent years. The steep PCB concentration reduction over time observed for the late 20th century levelled off during the last 20 years, and levels of PCBs appear to be at or near a steady-state condition.
PCB concentrations in Baltic Sea sediments appear to be at or near steady-state, and no significant concentration decreases are to be expected in the near future.
Department of Environmental Science and Analytical Chemistry (ACES), Stockholm University, SE-10691 Stockholm, Sweden. Electronic address: anna.sobek@aces.su.se.
Anna
A
Sobek
ÅF AB, Umestan Företagspark, SE-90347 Umeå, Sweden.
Kristina L
KL
Sundqvist
Department of Chemistry, Umeå University, SE-90187 Umeå, Sweden.
Anteneh T
AT
Assefa
Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences (SLU), SE-750 07 Uppsala, Sweden.
Karin
K
Wiberg
D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry*; D006581:Hexachlorobenzene / Q000032:analysis*; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D000072317:Polychlorinated Dibenzodioxins / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data*
D000072317:Polychlorinated Dibenzodioxins; D014874:Water Pollutants, Chemical; D006581:Hexachlorobenzene; D011078:Polychlorinated Biphenyls
Baltic Sea; HCB; Half lives; PCBs; Sediment; Temporal trend