Levels and trends of organochlorines in cod and herring in the northern Baltic

Cod and herring have been collected and analysed for monitoring purposes since 1979 in the Finnish sea areas in the Baltic Sea. During the period 1979–1986, both the DDT and the PCB concentrations have decreased in all the studied areas. sDDT-values in herring muscle have decreased from 0.7–2.2 mg kg −1 in 1979 to 0.3–1.0 mg kg −1 in 1986 (in extractable fat). Corresponding sPCB-levels have decreased from 2.7–3.7 mg kg −1 to 0.3–1.1 mg kg −1. The present lindane concentrations in herring vary from 0.010–0.017 mg kg −1, and the HCB concentrations from 0.013–0.019 mg kg −1 (extractable fat).