测定5种高环多环芳烃毒性当量因子并应用于太湖梅梁湾表层沉积物分析

作用位点和作用机理相同的污染物通常具有毒性加合作用,但是各个污染物对总体毒性的贡献并不相同,因此需要采用等毒性当量方法进行归一化．本研究选取了5种具有较强芳烃受体效应的多环芳烃(PAHs),通过大鼠肝癌细胞株H4ⅡE体外EROD酶诱导试验,得到相应的剂量／效应关系曲线,并计算了单个PAH的毒性当量因子 (EROD-TEF)．研究结果表明,不同PAH对EROD响应的EC50有较大区别,毒性相对强弱按照苯并k]荧蒽>茚并 1,2,3-cd]芘>苯并a]芘>苯并b]荧蒽>苊的顺序递减,对应的EROD-TEF值分别为1．1×10-4、3．0×10-5、3．9×10-6、 2．8×10-6和1．5×10-6．利用所得到的EROD-TEF值和气相色谱-质谱(GC-MS)联用方法测定的太湖梅梁湾地区表层沉积物中16种PAHs的浓度,计算得到5种PAHs的2,3,7,8-TCDD毒性当量TEQPAH,并与体外EROD酶诱导生物测试方法测得的表层沉积物毒性当量EROD-TEQ进行了比较．结果显示,两者间存在较好的线性关系(r2=0．65, p<0．05),证明实验测得的EROD-TEF值能够用于实际样品的分析;所研究的沉积物样品中5种PAHs对总芳烃受体效应的贡献均大于50％,表明PAHs是太湖梅梁湾地区表层沉积物中主要的芳烃受体效应活性物质,其可能引起的环境风险应得到进一步重视．

Detection of Toxicity Equivalent Factors for Five PAHs and Studies on Its Usage in the Sediment of Meiliang Bay, Taihu Lake

The pollutants which have the same mode of action or even the molecular site of action usually support toxicity additivity for mixtures. But each has its own degree of toxicity. To express the overall toxicity of such a mixture as a single number, the concept of "Toxic Equivalents" (TEQ) has been developed. Five PAHs with high Ah-accepter-effect were detected by EROD assay in H4 II E hepetoma cell line. The dose-effect relationship and toxicity equivalent factors (ERODTEF) were calculated. The study shows that the EC50 of PAHs investigated are different and the toxicity of PAHs rank as follows: Bkf>I(cd)P>Bap >Bbf > Chr showing the EROD-TEF are 1.1×10-4、3.0×10-5、3.9×10-6、2.8×10-6and 1.5×10-6 respectively. The concentrations of 16 PAHs in sediments were determined by gas chromatography equipped with a mass spectrometry(GC-MS). The total PAH levels were expressed as 2, 3, 7, 8-TCDD toxicity equivalents (TEQPAH) calculating by the factor of EROD-TEF and compared to the total toxicity equivalents (EROD-TEQ) tested by the in vitro EROD induction bioassay. The result shows that the TEQPAH values were in good correlation with the EROD - TEQ (r2 = 0.65, p<0.05)and the EROD-TEF can be used in environmental sample. The TEQPAH accounted for more than 50% of the EROD-TEQ. PAHs were the dominant contributor to the effect of Ah accepter in the sediment of Meiliang Bay, Taihu Lake. Considering this information, the environment risk of PAHs may not be ignored.