呼和浩特周边农田土壤中多环芳烃污染特征与生态风险评价

摘要

[Objective] This study was conducted to provide a scientific theoretical basis for pollution forewarning and agricultural planning. [Method] 15 PAHs were studied for pollution characteristics, source analysis and ecological risk assessment at 60 sites in Hohhot farmland. [Result] The results showed that the total contents of 15 PAHs (ΣPAHs) in 60 sampling points of Hohhot farmland were in the range of 114-948 μg/kg, with an average content of 338 μg/kg. According to soil PAH assessment standards, more than 70% of soil in Hohhot City was lightly polluted, and there were no heavily-polluted points. The soil of the area was mainly polluted by PAHs with high molecular weights, which accounted for 74% of the total content.The soil in suburban farmland of Hohhot suffered from the heaviest pollution. Quantitative analysis showed that PAH pollution in Hohhot farmland was mainly from combustion of coal, coke and timber and automotive exhaust emission. [Conclusion]Ecological effect interval method and method of equivalents equivalent to benzo (a)pyrene toxicity benzo [a] pyrene both proved that there is certain potential ecological risk for soil of Hohhot farmland, and PAHs with high molecular weights such as benzo (a) pyrene and dibenzo [a, h] anthracene are main potential pollutants with ecological risk.%[目的]为呼和浩特市农田土壤污染预警和农业规划用地提供科学理论依据.[方法]对呼和浩特市农田土壤60个采样点位中15种多环芳烃进行污染特征、 来源解析和生态风险评价.[结果]ΣPAHs含量范围为114~948μg/kg,平均含量为338μg/kg,参照相关研究评价标准判定,呼和浩特市农田土壤中70%以上属于轻微污染,不存在严重污染点位;研究区农田土壤中高分子量多环芳烃污染占总含量的74%,以近郊农田土壤污染最为严重;定量解析来源主要是煤、焦炭和木材的燃烧以及汽车尾气的排放.[结论]采用生态效应区间法评价和苯并(a)芘毒性等效当量法评价均证明呼和浩特市农田土壤存在一定的潜在生态风险,其中苯并[a]芘、二苯并[a,h]蒽等高分子量多环芳烃是主要潜在的污染物.