Toxic significance of planar aromatic compounds in Baltic ecosystem — New studies on extremely toxic coplanar PCBs

Abstract

Baltic salmon and white-tailed eagle samples have been analyzed for organochlorine compounds including polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, polychlorinated naphtalenes and toxic coplanar PCBs. In salmon, PCB and DDT residue contents were 0.2-0.3 ug/g in fresh muscle. Chlordanes, toxaphene, hexachlorobenzene, α-hexachlorocyclohexane and γ-hexachlorcyclohexane were found at 1 – 10 ng/g levels. Significant dioxin type of toxins found were only 2,3,7,8-tetrachlorodibenzofuran (45–81 pg/g) and 3,3′,4,4′-tetrachlorobiphenyl (638–1120 pg/g). Polychloronaphtalene contents in all salmon and eagle samples were of the same order of magnitude ranging from 4 to 85 ng/g. The highest chlorohydrocarbon contents in eagle samples were for PCB 462 ug/g, sum of the DDT residues 42 ug/g, chlordanes 5.7 ug/g and HCB 1.6 ug/g. In contrary, toxaphene, α-hexachlorocyclohexane and γ-hexachlorocyclohexane were not detected in eagles. Levels of polychlorodibenzo-p-dioxins, polychlorodibenzofurans and coplanar PCBs were highest ever reported in wildlife in adult eagle samples, in liver of a juvenile eagle and in eagle egg from South Finland ranging from 1 to 13 ng/g for PCDD/Fs and from 18 to 229 ng/g for coplanar PCBs. Calculation of the TCDD-equivalents of the contents gave that dioxin toxicity load comes in great excess from the coplanar PCBs, especially from 3,3′,4,4′,5-pentachlorobiphenyl.