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Very limited information is available on body burdens and environmental levels of dioxins and dioxin-like PCBs (dl-PCBs) in mainland China. In the current studies, human milk samples were collected from 30 breastfeeding mothers in Shijiazhuang city (industrialized) and 11 in the Tanshan countryside (agricultural) of Hebei Province in northern China. An additional 20 samples were obtained from mothers in Tokyo, Japan. PCDDs, PCDFs, and dl-PCBs in human milk were analyzed by high-resolution gas chromatography/high-resolution mass spectrometry. Our results show that arithmetic means for body burdens of PCDDs/Fs and dl-PCBs in Hebei were 3.6 and 1.9 pg TEQg(-1) fat, respectively, which were only about one fourth of the levels in Japan. In addition, no difference was found in the chemical levels except dl-PCBs between the urban and rural areas. Based on the results of an in-person interview of the Chinese mothers using a 59-item questionnaire, freshwater fish consumption was found to correlate with the body burden of dioxins. Principal component analysis of dioxin congeners revealed that the patterns of dioxins in the Hebei urban and rural areas are quite similar; however, they are clearly different from those in Japan. Collectively, our results suggest that the lower body burdens of dioxin in Hebei may be due in part to the relatively slow industrialization and a lower consumption of marine foods. Finally, the results indicate that comprehensive monitoring of dioxins and dl-PCBs in humans as well as in the environment and foods is necessary in China.

Human milk specimens from 55 women in Shijiazhuang urban and Tangshan rural areas in Hebei Province in northern China were collected and analyzed for persistent organic pollutants, such as p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE), hexachlorobenzene (HCB), beta-hexachlorocyclohexane (beta-HCH), and dioxins. We administered a questionnaire to milk donors at collection time, asking about lifestyle factors that potentially influence organochlorine pesticide (OCP) levels in human milk. We found that the concentrations of p,p'-DDE and beta-HCH in human milk from the primiparous mothers in Shijiazhuang (3330 and 108.8 ng/g fat, respectively) were higher than in samples from mothers from Tangshan (1916 and 21.2 ng/g fat, respectively). In addition, we found the level of p,p'-DDE correlated positively with a dietary history of meat consumption or consumption of internal organs of pigs and sheep (r=0.38 and r=0.52, respectively), but not with intake frequencies of vegetables and fruits in primiparous mothers. The higher level for p,p'-DDE may be due to a greater intake of contaminated fatty foods in the industrialized areas. We also showed that the body burden of p,p'-DDE was higher in the urban group compared to the values in other regions in China after 1998. However, there was no difference in dioxin levels between the two regions. Comprehensive monitoring of persistent organic pollutants in human milk and food is needed in China.