北京哺乳期女性及婴幼儿多环芳烃暴露风险变化特征

Exposure of Mother and Infants to Polycyclic Aromatic Hydrocarbons during Lactation,Beijing

多环芳烃(PAHs)是一类普遍存在于水圈、生物圈、岩石圈和大气圈的持久性有机污染物,并在各种环境介质中交换、迁移,从而影响人体健康。以母乳为介质,评价哺乳期女性和婴幼儿PAHs暴露风险具有重要意义。早期研究表明,北京母乳中PAHs浓度在全球范围内处于较高水平。本文项目组在2012—2016年间,连续采集北京地区30位哺乳期女性6个月母乳,并检测其中PAHs浓度,旨在掌握该地区母乳中PAHs残留水平、婴幼儿的暴露量,以及哺乳期母体和婴幼儿暴露风险的变化趋势与特征。通过对30位女性分娩后连续6个月内180个母乳中15种PAHs的监测,采用气相色谱-质谱法(GC-MS)测定其含量,初步研究结果表明:①15种PAHs都有检出,其中检出浓度和检出率高的单体化合物包括菲、芴、苊烯、蒽、苊和荧蒽。母乳样品中Σ15 PAHs的浓度均值为348μg/kg脂质,与2005年该地区的报道值相比有下降趋势。②15种PAHs和7种高致癌活性PAHs的苯并[a]芘的等效致癌活性(BaP eq)浓度分别为8.53μg/kg脂质和7.89μg/kg脂质,婴幼儿每日暴露估算值分别为1.51μg/day/kg b.w.和0.19μg/day/kg b.w.,均比2005年有所下降,但高于捷克、美国、土耳其等国家婴幼儿在母乳喂养期的暴露量,低于我国兰州等重工业城市最新暴露量研究结果。③整个哺乳期,母乳中PAHs的总浓度没有明显下降趋势,但冬季可能由于采暖增加了大气中PAHs的排放,使得母乳样品中15种PAHs总浓度明显高于夏季、秋季和春季。SPSS双变量相关分析结果表明,母乳中15种PAHs的总浓度与母体年龄、身体质量指数和母乳脂肪含量不存在相关性。未来工作中需要更加充足的样品分析数据进一步证实以上研究结果。

BACKGROUND:Polycyclic aromatic hydrocarbons(PAHs)are classic persistent organic pollutants in the hydrosphere,lithosphere,biosphere and atmosphere,which have a harmful effect on human health by exchanging and migrating among various environmental media.Breast milk is an ideal biometric to monitor the exposure risk of mothers and infants to PAHs.Earlier research indicated that the residue levels of PAHs in breast milk from Beijing were higher in the world.OBJECTIVES:To understand the changes in the residue levels of PAHs in breast milk in the region,the exposure of infants,and the trends and characteristics of the exposure risk of breastfeeding mothers and infants.METHODS:For 30 first-delivery women in Beijing,a breast milk sample per month within 180 days postpartum period was collected.The PAHs and fat content of breast milk were determined by gas chromatography-mass spectrometry(GC-MS)and monitored to study the time tendency of PAHs and estimate the exposure risk of infants to PAHs.RESULTS:The dominant pollutants were acenaphthylene,acenaphthene,fluorene,phenanthrene,anthracene,and fluoranthene.The average concentration of Σ15 PAHs in 180 samples was 348μg/kg lipid,which was lower than the value reported in 2005.Compared to the early reported residue level,the BaP-equivalent(BaP eq)concentrations decreased,which were 7.89μg/kg lipid for seven carcinogenic compounds,and 8.53μg/kg lipid for 15 PAHs.For breastfeeding infants in Beijing,the mean acceptable daily intakes(EDIs)ofΣ15 PAHs andΣ7 PAHs through breast milk were 1.51μg/day/kg b.w.and 0.19μg/day/kg b.w.,respectively,which was lower than those in 2005.However,it was higher than the exposure of infants in some countries such as Czech,America,Turkey during breastfeeding,and lower than the latest research results of Lanzhou and other heavy industrial cities in China.Throughout the lactation period,the total concentration of PAHs in breast milk did not decrease significantly,but winter heating may increase the emission of PAHs in the atmosphere,making the total concentration of 15 PAHs in breast milk samples significantly higher than that in summer,autumn,and spring.CONCLUSIONS:Bivariate correlations analytical results show that the concentration ofΣ15 PAHs is not associated with age,BMI and lipid content.Limited by sample size,those results should be confirmed with perfect experiment design and sufficient samples in future studies.