Concentrations and composition of PCB congeners in the air around stored used capacitors containing PCB insulator oil in a suburb of Bangkok, Thailand

Atmospheric PCBs were monitored around a site of stored used capacitors in a suburb of Bangkok, Thailand, from October 1991 to November 1992. Higher concentrations (820 ng/m 3 on average) were observed near by the storage area compared to those at 5 m leeward side (570 ng/m 3) while the capacitors were in the storage. After the capacitors were brought out from the storage, the concentrations decreased by approximately half and the compositions showed an enrichment of highly chlorinated congeners. Mixing ratio of PCBs volatilized from the capacitors and ambient soils on the surrounding ground at the sampling places was estimated by using PCB compositions as fingerprints. As a result, a quarter of PCBs in the air near the storage was estimated to originate from the capacitors and the remaining were from ambient soils. This is the first study to suggest the fate of PCBs dumped in a developing country in the tropical environment.