基于混合吸附剂被动采样及斑马鱼胚胎测试的效应导向分析：致毒物筛查中离子型化合物的毒性贡献

A large number of chemicals have entered aquatic environment, jeopardizing aquatic ecosystem and human health. An effective risk assessment method requires a thorough consideration of different types of chemicals, and thus a holistic screening of key toxicants in aquatic environment could be achieved. Currently, effect-directed analysis is the most widely used method to identify key toxicants in complex environment, yet its relevant technique needs to be improved. For instance, this method seldom considered concentration fluctuations of aquatic pollutants and only limited types of compounds could be extracted. It generally ignored the bioavailability and toxic contributions of ionizable compounds at different pH values in aqueous environments. In addition, the use of cell-based toxicity tests made it less environmentally relevant. These problems possibly lead to misjudgment or neglecting of key toxicants. The proposed project aims to develop and optimize a novel passive sampling method that can simultaneously enrich polar, non-polar and ionizable compounds from aquatic environment, hence more chemicals can be included in toxicity identification with a consideration of chemical concentration fluctuations in the environment. Then, zebrafish embryo toxicity tests will be conducted under different pH conditions and the impact of pH on the toxicity of ionizable compounds will be investigated. In the meantime, the effects will be used to guide identifying suspected toxicants. The implementation of the project will improve the understanding of the toxicity contribution of ionizable compounds and provide a scientific basis for developing methods to holistically screen key toxicants in water.

大量化学品进入水环境中，危害生态系统与人类健康。有效的生态风险评价方法需考虑不同类型的化合物，全面筛查水环境中关键致毒物。效应导向分析被广泛用于致毒物识别，但其相关技术尚需完善。例如，该方法较少考虑环境中污染物的浓度波动，筛查化合物种类不全面；未考虑离子型化合物在水环境不同pH值下的生物可利用性和毒性贡献；测试常用离体细胞，环境相关性较弱。上述问题可能导致水环境中关键致毒物的误判或遗漏。本项目拟研发并优化可同时富集水环境中的极性、非极性和离子型化合物的新型被动采样方法，在毒性筛查中扩大污染物类型并考虑其环境浓度波动；在不同pH值下，开展斑马鱼胚胎毒性测试，探讨pH值对离子型化合物的毒性影响机制，并以此为导向筛查可疑致毒物。该项目的实施有利于提升对复合污染条件下离子型化合物的毒性贡献认知，为发展致毒物筛查方法提供科学支撑。

大量化学品进入水环境中，危害生态系统与人类健康。有效的生态风险评价方法需考虑不同类型的化合物，全面筛查水环境中关键致毒物。本项目使用被动采样器萃取水环境中污染物，并结合可考虑因水环境pH值变化而离子型化合物呈现不同生物可利用性和毒性的斑马鱼胚胎活体生物毒性测试技术，建立了一套更具环境相关性的效应导向分析（Effect-directed analysis, EDA）复合毒性评估方法，将其用于筛查珠江广州段可疑关键致毒物。经目标化合物与可疑性筛查，在毒性分离组分中检出了新烟碱、氟虫腈、离子型药物、全氟类、酚类、麝香类和多环芳烃等化合物。通过查询毒性数据并结合检出浓度，推测氟虫腈、氟虫腈砜、离子型的化合物磺胺甲恶唑与苯海拉明、佳乐麝香、吐纳麝香、萘和芘可能具有显著毒性贡献。同时，在对关键可疑致毒物进行筛查的基础上，通过目标化合物分析测定了当前正广泛使用的新烟碱类杀虫剂及其转化产物在珠江广州段及污水处理厂出水中的残留。研究结果显示，珠江广州段母体化合物和转化产物其总浓度范围分别为53.8 ± 6.7–81.5 ± 9.9和8.43 ± 0.45–15.1 ± 1.4 ng/L，污水处理厂母体化合物和转化产物其总浓度范围分别为217 ± 18–599 ± 31和63.0 ± 3.0–131 ± 9 ng/L。项目的实施，为复合水污染环境条件下水体关键致毒物筛查及新烟碱类杀虫剂的环境行为研究提供了科学方法，增加了其在水环境风险评价和管控中的应用潜力。