电子垃圾拆解排放VOCs暴露的尿液代谢特征及代谢机制研究

Volatile organic compounds (VOCs) are a kind of important atmospheric toxic organics emitted during e-waste dismantling process. They may affect the ecosystem and have adverse effects on public health. However, to date, there is still lack of valuable data relating to risk assessment of VOCs discharged from e-waste dismantling industry. Hence, urine samples were collected for identification the exposure levels of VOCs in e-waste recycling workers in Guiyu town. A rapid analysis method of individual VOC congener and its metabolites will be developed using purge and trap-chromatography-mass spectrometry and high performance liquid chromatography-tandem mass sepctrometry, respectively. A parallel systematic study about VOCs uptake in both group of subjects was carried out, establishing the correlation between urinary VOC concentrations of people exposed and the concentrations found in the e-waste dismantling process. The potential biomarkers were identified by metabolomics analysis between the exposure level of VOCs and the changes in endogenous metabolism. Based on this, metabolic mechanism of VOCs will be studied by a metabolic experiment in vitro using liver microsomes. This study will make a breakthrough in public health issue of environmental pollution and human health of VOCs during e-waste recycling process, and be helpful to provide scientific data for environment improvement in this highly polluted area.

挥发性有机化合物（VOCs）是电子垃圾拆解过程排放的一类重要的大气毒害有机物，对生态环境和人体健康造成巨大的潜在危害。然而，目前对电子垃圾拆解过程排放VOCs的暴露风险研究十分有限。本项目拟以我国最大的电子垃圾拆解基地贵屿为研究区域，采集暴露人群尿液样品，建立尿液中多种VOCs及代谢产物的快速分析方法；分析暴露人群与对照人群尿液中VOCs及代谢产物的浓度水平，提供电子垃圾拆解区VOCs暴露人群的指纹图谱，阐明外暴露与内暴露的相关性；进一步通过代谢组学分析，全面考察暴露人群尿液代谢物水平的变化，通过多重分析将VOCs暴露水平与内源性代谢水平的变化关联，寻找潜在的生物标志物；并结合肝微粒体体外代谢实验，探索VOCs暴露的人体代谢机制。本项目有望在电子垃圾拆解区VOCs的环境污染与人群健康这一公共健康问题上取得突破性进展，为推进电子垃圾拆解绿色转型和保护环境及人体健康提供参考。

目前对电子垃圾拆解过程排放的挥发性有机化合物（VOCs）的暴露风险研究十分有限。本项目通过优化前处理、色谱及质谱条件，结合吹扫捕集-气相色谱质谱联用仪和高效液相色谱-质谱联用仪分别建立了尿液中64种原型VOCs和10种代谢产物的方法；以典型电子垃圾拆解工业园为研究区域，采集园区内外共198个环境VOCs样品，125份职业拆解工人和45份居民尿液样品，利用上述已建立的方法分析了尿液中苯、甲苯、乙苯和二甲苯（BTEX）代谢物的浓度水平。结果表明，拆解工人普遍暴露于高浓度的BTEX，尿液中代谢产物的中值浓度比未代谢BTEX的中值浓度高约6个数量级。BTEX在内外暴露中呈现不同的特征。尿液中N-乙酰基-S-苄基-L-半胱氨酸的浓度与环境大气中BTEX同系物的浓度均呈现显著的正相关。95.2%的工人通过暴露BTEX产生累积致癌风险，基于苯的代谢暴露水平评估发现，99.9%的职业工人的致癌风险超过1.0E-6。进一步分析发现，职业工人尿液中BTEX代谢产物总浓度与居民无显著差异，而MA、2-MHA、4-MHA、3-MHA和S-PMA的浓度显著高于居民；通过代谢组学筛选出79种重点关注的代谢物，经过KEGG注释，筛选出涉及丙氨酸、天门冬氨酸和谷氨酸代谢、嘌呤代谢、精氨酸和脯氨酸代谢、β-丙氨酸代谢、嘧啶代谢、D-谷氨酰胺和D-谷氨酸代谢、柠檬酸循环和乙醛酸盐和二羧酸盐代谢途径。肝微粒体复合暴露实验表明，BaP代谢依赖于苯、甲苯、氯苯和硝基苯（MAHs）的浓度、肝微粒浓度和培养时间。MAHs复合暴露对BaP葡萄糖醛酸化产生负面影响。MAHs复合暴露导致OH-BaP-G和diOH-BaP-G代谢强度分别下降至43%~80%和32%~71%。此外，葡萄糖醛酸化作用受到竞争性和时间依赖性抑制的影响。本研究为制定VOCs的消减和保护职业工人健康提供了科学参考。