Prenatal and postnatal transfer of pesticides to children

有机氯农药是一种广泛存在于环境中的化合物，由于其持久性和高度亲油性，它们在生物系统中积累。新生儿通过胎盘和母乳喂养接触到这些有机氯化合物。本研究对20位母亲的母乳和胎盘中的几种有机氯农药进行了分析，以确定主要的农药化合物。这项研究是我们前瞻性队列研究的一部分。2001年1月至2003年9月，在东北地区两家医院的产科病房，在知情同意的情况下招募了健康孕妇。该研究方案得到了东北大学大学院医学部医学伦理委员会的批准。所有母乳和胎盘样品中均检出六氯苯、β-六氯环己烷、环氧氯丹、顺式、反式九氯、p，p‘-DOT、p，p’-滴滴涕、狄氏剂和七氯氧烷。分析母乳中农药与胎盘的关系，考察胎盘作为暴露评估材料的利用情况。结果表明，母乳样品与胎盘样品中各主要农药的相关性良好，胎盘可作为估算母体体重的有用材料。此外，胎盘样品中六氯苯、环氧氯丹和反式十一氯等有机氯农药的浓度与产次呈显著负相关。这一发现清楚地表明，母亲在怀孕期间和通过母乳喂养她们的孩子来消除这些杀虫剂。母乳样品和胎盘样品中的环氧氯丹、二十五烷、狄氏剂和七氯氧自由基的浓度与鱼的摄入量相关；而六氯苯、六氯环己烷和DDE则没有相关性。这些结果表明，鱼类消费对农药摄入量的贡献取决于农药的种类。

Organochlorine pesticides are compounds widespread in the environment due to their persistence and highly lipophilic nature, and they accumulate in biological systems. Newborns are exposed to these organochlorine compounds across the placenta and through breastfeeding. In the present study, several organochlorine pesticides were analyzed in human breast milk and placenta from 20 mothers to identify the major pesticide compounds. This study was performed as part of our prospective cohort study. Healthy pregnant women were recruited with their informed consent at obstetrical wards of two hospitals in Tohoku between January 2001 and September 2003. The study protocol was approved by the Medical Ethics Committee of the Tohoku University Graduate School of Medicine. HCB, β-HCH, oxy-chlordane, cis-nonachlor, trans-nonachlor, p,p'-DOT, p,p'-DDE, dieldrin, and heptachlorepoxide were found from all breast milk samples and placenta samples. The relationship between pesticides in breast milk and the placenta was analyzed to examine the utilization of the placenta as the material for exposure assessment. The results showed that since there were excellent correlations of all major pesticides between breast milk samples and placenta samples, placenta was suggested to be the useful material to estimate the maternal body burden. In addition, the concentrations of some organochlorine pesticides ouch as HCB, oxy-chlordane, and trans-nonachlor, in the placenta samples had significant negative correlations with parity. This finding clearly shows that the mothers eliminate these pesticides during pregnancy and by breastfeeding into their children. The concentrations of oxy-chlordane, nonachlors, dieldrin, and heptachlorepoxide in breast milk samples and placenta samples were correlated with fish consumption ; however, HCB, HCH, and DDE had no association. These results indicated that the contribution of fish consumption to the intake of pesticides depended on the kind of pesticides.