PCBs and organochlorine pesticides in Lake Orta (Northern Italy) sediments

PCB congeners and organochlorine pesticides (DDT, lindane and HCB) distribution were studied in take Orta sediments. The results indicated a contaminated area in the northern part of the sub-basin. The observed high levels of organochlorine compounds (OCs) may be explained by the focusing phenomenon, ie. the preferential transport of lighter and smaller particles from the emission sources to this area. The PCBs and DDT values were correlated with the organic carbon content and the heavy metal contamination. The toxicity of the sediment samples was related also to PCB content. PCBs and OCs pollution of Lake Orta was of the same order of magnitude as in Lake Como, which is the most contamined lake in Northern Italy.