合成麝香在母体-胎盘中的分布特征和迁移转运行为

Synthetic musks, a kind of emerging contaminant, are ubiquitous in environment, biota and human tissues due to their continuous use. The human exposures on synthetic musks are of great concern in European Union countries and other regions since their high exposure frequency and potential health hazards related. But there are few studies conducted in China. .This research project will be focusing on occurrence and distribution characters of main synthetic musks in breast milk, maternal blood and cord blood collected from Shanghai, which including galaxolide (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8- hexamethylcyclopenta[γ]-2-benzopyran, HHCB), tonalid (7-acetyl-1,1,3,4,4,6- hexamethyl-1,2,3,4-tetrahydronaphthalene, AHTN), musk xylene (1-tert-butyl-2,6- dimethyl-2,4,6-trinitrobenzene, MX) and musk ketone (4-tert-butyl-2,6- dimethyl-3,5-dinitroacetophenone, MK). The current contamination status on mothers and neonates will be elucidated using research data. The exposure levels and potential health risks for both mothers and neonates will also be assessed. .It is important to understand the extent of prenatal exposure to musks. Thus, the transfer behavior in maternal-placental unit will be studied in this research project. Matching samples containing breast milk, maternal blood, cord blood and placenta will be analyzed in this research. The concentrations, transfer ratio, and influence of maternal exposure will be discussed to explore possible transfer mechanisms. The distribution and transport characteristics between blood and breast milk will also be investigated. .Moreover, to better understand transport characteristics and placental transfer mechanisms, changes in enantiomer composition of chiral HHCB and AHTN will be studied. The potential enantioselective migration (or enrichment) in maternal-placental unit and blood-milk unit will be explored. Changes in composition of musk parent compounds and metabolites will also be discussed to know metabolism influence on transfer mechanism..More comprehensive contamination data on female and newborn baby will be obtained through this study. The transfer characteristics and mechanisms in maternal-placental unit and blood-milk unit will be better understood after this investigation. Also the change on enantiomer compositon of chiral musks during transport will be knowed. This may provide more benefit for further human health risk assessment and musk pollution control by local government, and is helpful for appropriately musk production and use pattern.

合成麝香是一种具有持续暴露特性的新型有机污染物，由于它的普遍存在和对人体的潜在健康危害，受到国际社会广泛关注，但有关人体迁移机制研究较少。本课题拟选取上海市产妇人群母血/母乳以及新生儿脐血/胎盘为研究对象，以佳乐麝香、吐纳麝香、二甲苯麝香和酮麝香为目标化合物，系统研究合成麝香在上述人群的分布特征和迁移行为。在建立和完善相关分析方法的基础上，研究合成麝香在产妇及新生儿的内暴露水平和赋存形态，探讨女性暴露健康风险和对新生儿的早期影响；研究合成麝香从母血到母乳，从母血到脐血的分布过程，探讨体内迁移特性以及母体-胎盘的转运作用；研究代谢物组成及手性合成麝香的结构分布特点，探讨迁移过程的构型变化和立体选择性。该课题的研究有助于全面把握合成麝香污染现状，深入了解合成麝香体内迁移的规律，推动合成麝香健康风险评价理论的进一步发展，为污染物控制决策提供科学的数据支持，也可为企业生产和女性合理使用提供科学依据

通过对母血、母乳、脐血等300多例人体样本的系统分析，发现上海育龄女性体内普遍存在合成麝香污染。总浓度中值在43.1-68.8 ng/g脂重；0.22-0.94 ng/mL，胎盘0.52 ng/g湿重，污染水平中等偏下；HHCB、HHCB-lactone为主要麝香污染物。母血、母乳和脐血、胎盘的浓度在同一数量级水平，反映育龄女性体内麝香污染负荷对胎儿孕育环境的直接影响。.麝香污染物组成以多环的HHCB为主，也有一定量MK的存在。母血、脐血和胎盘的组成分布较类似，但母乳的组成特征与它们有明显区别，说明母血、脐血和胎盘介质中的麝香污染物具有同源性。数据分析结果显示血液麝香浓度受到皮肤类型的一定影响，但与年龄、胎次等因素不具有相关性，护肤品使用习惯也未对其产生明显效应。麝香体内累积水平变化受到个体吸收程度的影响更为明显。.HHCBs在脐血和胎盘中的普遍存在说明存在HHCBs的母体-胎儿转移过程，可对新生儿形成宫内暴露。依据污染物的介质分配特性和配对样本的浓度比数据，发现母体对HHCB、HHCB-lactone和AHTN的保留能力均弱于胎儿环境。HHCB、HHCB-lactone容易从母血渗透转移至脐血中；转移过程中浓度有所增加；胎盘屏障作用较弱。AHTN的脐血/母血转移率小于1，对AHTN有一定的胎盘屏障抑制作用，保留在胎盘中的量相对较多。HHCBs主要通过脐血对胎儿产生宫内暴露；而AHTN宫内暴露的影响主要通过胎盘产生。母乳HHCB、HHCB-lactone的浓度受到母血影响。但母血污染物经脂肪累积后再转移至母乳的比例较低。.HHCB在母血-胎儿迁移过程中存在一定程度立体选择性，会引起立体组成偏移。脐血相对积累较多的trans-HHCB，对映体组成也偏离外消旋，以 (+)-trans-HHCB优先。母血和脐血的情况较类似。胎盘的cis结构对映体组成有变化，表现为对(-)-cis-HHCB的立体优先性积累。胎盘和脐血HHCB的trans/cis结构比及产生旋光性构型的不同，说明HHCB在脐血和胎盘间的迁移具有一定立体选择性。.此外还分析了这些样本中有机氯农药OCPs的污染特征，评估了新生儿的日暴露水平。DDTs、HCHs、HCB的体内污染水平显著高于合成麝香，污染浓度具有年龄累积性；但它们的胎盘转移特性和合成麝香存在区别。摄入量估算显示新生儿通过母乳摄入DDTs量需关注。