被动式采样器与原位鱼体暴露用于监测水体Ah受体效应的比较研究

Comparison of the Methods for Assessing Ah Effects in Aquatic System by Semipermeable Membrane Device and Caged Fish

采用被动式采样器SPMD结合H4ⅡE鼠肝癌细胞离体EROD测试的方法来评价水体中Ah受体效应物质的污染水平．以多环芳烃（PAHs）为目标化合物，在太湖梅梁湾地区选取了5个站点，同时放置SPMD采样器和笼养鲫鱼进行32d的现场原位暴露实验，然后对SPMD样品提取液进行化学分析和离体EROD测试，对鱼肌肉样进行化学分析和对肝胰脏样进行活体EROD测试．结果表明，随着暴露时间的延长，SPMD样品提取液诱导EROD酶的能力逐渐增强，经过32d暴露的SPMD样品的提取液其诱导的EROD酶活相当于TCDD的毒性当量值为3．8～6．2Pg／g，而且根据化学分析结果计算的PAHs相当于TCDD的毒性当量值与离体生物测试结果之间相关性很好（R0=0．88），说明PAHs是引起该地区水体EROD效应的一个重要诱导因子；根据化学分析结果而配制的模拟样品的离体EROD测试结果表明，多环芳烃类物质对梅梁湾地区水体Ah受体效应的贡献约为40％～50％．研究还发现，SPMD提取液离体EROD测试结果与同时暴露的鱼体肝胰脏的活体EROD测定结果之间也存在较好的相关性（R^2=0．62）。因此认为，SPMD结合离体EROD测试的方法能够很好的用于评价水体中Ah受体效应物质的污染水平，并能够用于揭示特定化合物与相应的生物效应之间的定量关系。

Semipermeable membrane devices （SPMDs） in combination with in vitro ethoxyresorufin-O-deethylase （EROD） assay was used to assess the aryl hydrocarbon receptor （AhR） effects in aquatic system. In present work, polycyclic aromatic hydrocarbons （PAHs） were selected as target compounds and SPMDs were deployed simultaneously with caged crucian carp for 32 days at five sites in Meiliang Bay, Taihu Lake. The concentrations of PAHs in the SPMD dialysates and fish tissues were analyzed by gas chromatography-mass spectrometry. In addition, the EROD activity of SPMD dialysates was assayed with H4ⅡE rat hepatoma cells and the induction of EROD activity in pancreas and liver of fish was also assayed. It was found that dialysates from SPMDs with longer exposures generally induced stronger activity and the toxic potency of dialysates expressed as bioassay-derived 2, 3, 7, 8- tetrachlorodibenzo-p-dioxin （TCDD） equivalents ranged from 3.8 pg/g to 6.2 pg/g for 32 days exposure. A correlation of toxicity equivalency quantity （TEQ） with chemical analysis and in vitro bioassay-derived TEQbio of SPMD dialysates yielded an R2 of 0.88, therefore,indicated that PAils were one of the important AhR agonists in the water. Empirical evidence suggests that PAHs can account for about 40 % to 50 % of the potency observed. Moreover, a good correlation was observed between the results of EROD bioassay in vivo and EROD bioassay in vitro （R^2 = 0.62）, thus reflected that these two methods can be complementarily each other. It is, therefore, suggested that the SPMD technique combined with chemical analyses and in vitro EROD assay might be a valuable monitoring tool to assess the levels and effects of AhR agonists in water ecosystem.