| Persistent organochlorines (POCs), represented by hexachlorocyclohexane (HCH), polychlorinated biphenyl (PCB), and dichlorodiphenyltrichloroethane (DDT), are endocrine disrupters which have persistency, biomagnification effect, and can accumulate in human adipose tissues. Some studies give evidences that POCs may have toxicity to respiratory system, neuroendocrine system, and reproductive system. Assessing the exposure level of POCs in human and the risk ratios to human health is very important to take appropriate preventive measures in future. The main study contents and results are as follows:(1) DDT levels in132agricultural soil samples covering the entire region of China (except for Hongkong and Macau) were determined. Dietary intake of DDT for six food types and four dietary regions was modeled. Population attributable fraction (PAF) was used to assess the DDT exposure risk to breast cancer. Higher DDT concentrations were found in the main agricultural regions, the median value of total DDT components was2.60ng/g with range from0.37to547.03ng/g, and DDT exceeding the regulatory limit of100ng/g was found to impact42.3million Chinese population. Considering the geographical differences with diverse DDT contributions and different diet products and habits, the average daily dietary intake (DDI) was estimated to be0·34?g/kg/day p,p'-DDE (the main bioactive constituent in DDT). Based on the estimated PAF with a median value of0·60%(IQR0·23%-2·11%), the excess annual breast cancer incidence rate attributable to p,p'-DDE exposure averaged006×10-5in Chinese females. Exposure to DDT is a contributor to breast cancer, but the overall limited PAF imply confounding factors for breast cancer in Chinese females such as gene susceptibility and lifestyle.(2) The POCs may pass through the placental barrier and affect the development of the next generation. We conduct an epidemiological survey on the pregnant women and their infant who are fish consumers living on the island facing the Yangtze River estuary. Most agricultural non-point source pollution discharge into sea through the Yangtze River estuary and these pollutions may threaten the health of the islanders. Questionnaires including the mother's sociodemographic characteristics, dietary structure, reproductive history, the growth and development of infants were collected. Combined with the detection of HCHs concentration in umbilical cord blood, we assessed the effect of infant development from exposure to HCHs. The result showed that the weight and and longth of the infant were in a higher level compared with infants in other regions; HCHs concentrations in umbilical cord blood were high compared with the results is other studies; and we found no association between HCHs residue and T2DM by t test.(3) Exposure to organochlorine pollutants is considered the risk factor of type2diabetes. To quantitatively evaluate the association and pool the inconsistent evidence, we performed a meta-analysis. Publications in English were searched in medline and web of science databases and finally23studies were extracted. All the estimate values including odds ratio (OR) and relative risk (RR) were pooled. Rigorous quality assessment was performed, and considering the heterogeneity sources, subgroup analyses were conducted. The pooled OR of PCB-153, PCBs, and p,p'-DDE was1.52(confidence interval, CI,1.19-1.94),2.14(CI,1.53-2.99),1.33(CI,1.15-1.54), respectively. The results indicates that exposure to POCs is associated with an increased risk of T2DM. |
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