Pham Hung Vieta, Nguyen Hung Minha,b, Tu Binh Minhb, Shinsuke Tanabeb
aCenter for Environmental Technology and Sustainable Development
Hanoi National University
bCenter for Marine Environmental Studies, Ehime University, Japan
Although polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were officially banned in Vietnam since the mid 1990s, some recent studies on various environmental samples have found consistent evidences of ongoing applications of some OCPs, especially DDTs and HCHs. Despite this fact, no comprehensive studies on contamination of such toxic substances in Vietnamese human as a result of bioaccumulation through food chains have been made in recent years. In this study, we collected human breast milk samples from the Hanoi (n = 42) for determination of PCBs, DDT and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), hexachlorobenzene (HCB), chlordane compounds (CHLs) and an emerging contaminant namely tris-4-chlorophenyl-methane (TCPMe). The contamination pattern of the above organochlorines was in order DDTs > PCBs > HCHs > CHLs » HCB » TCPMe. Compilation of available data indicated that DDT residue levels in human breast milk from Hanoi, Vietnam (2200 ng/g lipid wt) were the highest among the values reported for Asian developing countries as well as developed nations. This result suggests recent usage of DDTs in the country. Interestingly, the p,p’-DDT was higher in multiparas than those in primiparas, indicating continuous intake of DDTs by this population. The mean concentration of PCBs as the second predominant contaminant was 75 ng/g lipid wt, which was lower than those in developed nations but higher than those in other Asian developing countries. Analysis of infant exposure to DDTs via breast milk suggested that the daily intake rates by many individuals are close to or above the threshold for adverse effects, which may raise concern on child health in Vietnam.