Persistent organochlorine residues in air, water, sediments, and soils from the lake baikal region, Russia.

Contamination of semivolatile organochlorines (OCs) such as hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs), DDTs, chlordanes, and polychlorinated biphenyls (PCBs) was assessed in air, water, sediments, and soils from the Lake Baikal region, Russia. Comparison of the residue levels in the lake with those in other regions suggested the presence of local sources of DDTs and PCBs, although the residues were considered to be lower than those in the low-latitude areas in the eastern Asia and Oceania. Larger proportions of p,p'-DDT to total DDTs and similarities of PCB congener compositions to a Russian technical PCB formation were found in the samples analyzed, implying their usages nearby the lake. The estimated fluxes of OCs by gas exchange across the air-water interface applying the two-film model indicated that the lake water plays a role as a sink for HCB, HCHs, and DDTs and also serves as a source for PCBs. The magnitude for PCB volatilization in this lake was found to be smaller than those in the Great Lakes for which the values have been previously reported.