Persistent organochlorine pesticides and polychlorinated biphenyls in some agricultural and industrial areas in Northern Vietnam Available to Purchase

Organochlorine pesticide and polychlorinated biphenyl residues were determined in soils and surface sediments collected from Hanoi City, Viettri City and Halong Bay, which are representative of industrial and agricultural areas in northern Vietnam. Polychlorinated biphenyls (PCBs) and organochlorine insecticides such as DDT and its metabolites (DDTs) and lindane were detected in all samples analyzed, indicating the widespread contamination by these compounds in the environment of the north of Vietnam. Concentrations of DDTs and lindane were found to be highest in sediments from Halong Bay, followed by those in Viettri and Hanoi. PCB residues ranged from 0.64 ng g^–1 120 ng g^–1 (dry weight basis) in sediments and these levels were generally higher than those in soil samples. In general, higher concentrations of pesticides and PCBs were recorded in Halong Bay, suggesting the local sources in this area, probably from mining activities. High accumulation of DDTs in soils, sediments and biotafrom north to south Vietnam indicates that the recent input of DDT is still occurring throughout the country.