Contamination sources in Latvia: Levels of organochlorines in perch (Percafluviatilis) from rivers Daugava and Lielupe

This study was aimed to search for potential sources of polychlorinated bip henyls (PCBs) contributing to the PCB input to the Gulf of Riga, as part of the Baltic Sea. PCBs, DDT and related compounds, hexachlorobenzene (HCB), bis(4-chlorophenyl) sulfone (BCPS) and two hexachlorocyclohexane (HCH) isom ers were quantified in perch (Perca fluviatilis) from the rivers Daugava an d Lielupe in Latvia. Local PCB contamination was indicated in Lielupe with the most likely origin being the Jelgava urban area. The BCPS concentration s increased from 53 to 160 ng g(-1), based on lipid weight, (l.w.) progress ively measured downstream of the Lielupe. Local sources of p,p'-DDT and HCH s appeared to constitute the background contamination downstream from the R iga metropolitan area, on the River Daugava. The concentrations of organoch lorines were in the same range as reported for these contaminants in perch from other areas in the Baltic Sea region; e.g. PCB levels of 250-1100 ng g (-1) l.w. were determined.