Prenatal and postnatal transfer of pesticides to children

有机氯农药是广泛存在于环境中的化合物，由于其持久性和高度亲脂性，它们在生物系统中积累。新生儿通过胎盘和母乳喂养接触这些有机氯化合物。在本研究中，分析了20位母亲的母乳和胎盘中的几种有机氯农药，以确定主要的农药化合物。本研究作为我们前瞻性队列研究的一部分进行。2001年1月至2003年9月，在东北两所医院的产科病房招募了知情同意的健康孕妇。研究方案获得了东北大学医学研究生院医学伦理委员会的批准。在所有母乳样本和胎盘样本中均发现了六氯苯、β-六氯环己烷、氧氯噻嗪、顺式-九氯、反式-九氯、p，p '-DOT、p，p'-DDE、狄氏剂和七氯环氧化物。分析母乳中农药与胎盘的关系，以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主要农药残留量之间存在良好的相关性，胎盘可作为估算母体农药残留量的有效材料。此外，胎盘样品中的一些有机氯农药如六氯苯、氧氯菊酯和反式九甲草胺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子女消除了这些农药。母乳样本和胎盘样本中的氧氯菊酯、九氯、狄氏剂和七氯环氧化物的浓度与鱼的食用量相关;然而，六氯苯、六氯环己烷和DDE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.