利用化学分析和生物测试方法比较研究污染土壤中芳烃受体效应物质的积累

长期使用污水或再生水灌溉的潜在生态风险已经引起普遍关注,但是少有研究持久性有机有毒物质在土壤中积累所产生的慢性毒性.采用7-乙氧基-异吩唑酮-脱乙基酶(EROD)方法测试了北京郊区某再生水灌溉土壤中的芳烃受体效应物质,并用2,3,7,8-TCDD标定出相应的二英毒性当量(TEQ_bio).同时利用化学分析得到的土壤中16种多环芳烃(PAHs)的含量,根据文献报道毒性当量因子(TEF)换算成二英的毒性当量(TEQ_PAHs).分析生物测试的结果,发现灌溉土壤中芳烃受体

Comparative Study on Accumulation of Ah-Receptor Agonists in Contaminated Soil Based on EROD Bioassay and Chemical Analysis

The potential ecological risk by wastewater or reclaimed water for irrigation is of great concerns in recent years,but little work was done on the chronic toxicities through long term accumulation of persistent organic chemicals in soil.In present work,concentration of Ah-receptor agonists in soil organic extract was measured by an ethoxyresorfin O-deethylase(EROD) bioassay,which was calibrated and expressed by the 2,3,7,8-tetrachlorodibenzo-p-dioxin(2,3,7,8-TCDD) toxic equivalent(TEQ_bio).Simultaneously,16 PAHs in soil were analyzed and their TEQs(total as TEQ_PAHs) were calculated according to their toxic equivalent factors(TEFs) cited from literature.By bioassay,it was found that the concentration level of Ah-receptor agonists in soil irrigated using reclaimed water could be as high as 97.4 ng/kg,which was obviously higher than that in background soil using ground water irrigation regime(56.0 ng/kg). In comparing the results from bioassay and chemical analysis,the percentage of TEQ_PAHs in TEQ_bio increased from 10.3% in background soil to 78.6% in the soil irrigated by reclaimed water.Use of reclaimed water for irrigation could result in the accumulation of Ah-receptor agonists in soil,and a major part of them in this case could be attributed to the accumulation of 16 priority PAHs in soils.