Occurrence, Sedimentation, and Spatial Variations of Organochlorine Contaminants in Settling Particulate Matter and Sediments in the Northern Part of the Baltic Sea

Abstract

Sediment trap sampling of settling particulate matter (SPM) was carried out in remote coastal and offshore stations in the Bothnian Bay (BB) and the Bothnian Sea (BS) located in the northern Baltic Sea. This was done to investigate occurrence, composition profiles, sedimentation, and spatial differences of PCBs, HCHs, hexachlorobenzene, DDTs, chlordane compounds, and dieldrin. The contamination load at the coastal stations was compared to that of surface bottom sediments. At one coastal station, sediment samples were collected in two different seasons (autumn and spring) in order to compare seasonal variations. All compound groups were found in the SPM and sediment samples analyzed. The contaminant concentrations in SPM at the coastal stations ranged, on dry weight basis, from 0.41 to 8.6 ng/g for chlordanes and HCHs and at the offshore stations from 3.2 to 31 ng/g for hexachlorobenzene and PCBs. The levels in SPM at the offshore stations were 10 times higher (on the average) than the coastal stations, likely because of an increased carbon content in the offshore SPM. The profiles of compounds in SPM reflect the corresponding sediment profile, and only small differences in concentrations and profile of compounds between autumn and spring surface sediments were observed. A comparison between the BS and the BB for offshore and coastal stations showed that the concentrations of compounds were similar although the sedimentation of contaminants, estimated by down fluxes collected in the sediment traps per unit of time, was 3-5 times higher in the BS than the BB. The total annual sedimentation volume of PCBs was approximately 1.1 ton/yr in the BS and 0.4 ton/yr in the BB. An extrapolation to total sedimentation of PCBs during 1 year in the whole Baltic Sea resulted in an approximate value of 7 ton/yr.

Polychlorinated hydrocarbons in fishes, blue mussel (Mytilus edulis) and bottom sediments of the south-western Baltic Sea

“…Lower PCB concentrations in the bottom sediments were recorded at all sampling sites in the areas of Warnemünde and ÂwinoujÊcie, particularly at sites W 2 and S 1 . Concentration levels of the compounds studied in the areas of Warnemünde and ÂwinoujÊcie are consistent with the results of Strandberg et al (1998) from northwestern Baltic Sea and only the present data from the Kiel coast were much higher.…”

Concentrations and potential health hazards of organochlorine pesticides in shallow groundwater of Taihu Lake region, China

“…Differences in composition of OCP isomers/metabolites in the environment can reveal different pollution sources (Doong et al, 2002;Zhou et al, 2006) and various ratios have been used to identify the sources of OCPs (Strandberg et al, 1998;Bidleman, 1999;Hong et al, 1999;Covaci and Hurab, 2001). However, the OCPs in groundwater are not derived from direct inputs and the ratios of OCP isomers/metabolites will change during transport due to differences in their physical and chemical properties.…”

Levels and patterns of organochlorine pesticides in agricultural soils in an area of extensive historical cotton cultivation in Henan province, China

“…In the environment, α-and γ-HCH can be converted to β-HCH, which is more stable than the other HCH isomers (Kim et al 2007). However, photochemical transformation and biodegradation may transform γ-HCH to α-HCH (Strandberg et al 1998). DDTs are more persistent than HCH in soil and the residues of HCH were lower than DDTs in surface soil (2.93 to 56.41 ng g −1 for HCH, and from BDL to 206.13 ng g −1 for DDTs).…”