太原市污灌区农田土壤中多环芳烃污染特征及生态风险评价

通过对污灌区农田土壤多环芳烃(Polycyclic Aromatic Hydrocarbons,PAHs)的分布特征、污染程度及来源进行解析,深入了解污水灌溉引发的土壤污染问题,实现污水灌溉农田土壤的污染预警和科学合理利用.在太原污灌农田共采集110个土壤样品,使用气相色谱-质谱仪(Gas Chromatography...

Pollution Characteristics and Risk Assessment of PAHs in Agricultural Soil from Sewage Irrigation Area of Taiyuan City,Shanxi Province

This study explored the distribution characteristics,pollution status and the source of polycyclic aromatic hydrocarbons(PAHs)in farmland soils in sewage irrigation area to reveal and better understand soil pollution problems caused by sewage irrigation.A total of 110 soil samples were collected from farmlands around the sewage irrigation area in Taiyuan city.The 16 priority-controlled PAHs recommended by USEPA were analyzed by gas chromatography-mass spectrometery(GC-MS)to distinguish their compositions and contents.Principal Component Analysis and Multiple Linear Regression(PCA/MLR)were employed to identify the PAHs source.The mean Effect Range-Median Quotient method(Q_MERM)and the toxicity equivalent quantity method(Q_TE)were used to assess the ecological risks.The results showed that the average PAHs content was 3197.57μg·kg^-1 in the sewage irrigation area,dominated by 4?6 ring PAHs.In the Xiaodian area,the pollution sources of PAHs included fossil fuel combustion and coking sources(66.9%),as well as the coke source(33.1%).In the Jinyuan area,the fossil fuel combustion accounted for 53.2%of pollution sources,while the other half were mainly from coal and coking combustion(46.8%).In the Qingxu area,the PAHs pollution was mainly caused by fossil fuel combustion(88%).The secondary cause was the co-combustion of coal,wood and coke(12%).Results of the risk assessment showed that the agricultural soil was low or moderate in toxicity.The Xiaodian area showed a higher PAHs value based on the Q_TE results,followed by Jinyuan and Qingxu areas.Moreover,the 7 carcinogenic PAHs were the main source compositions which accounted for more than 90%of PAHs contents.Benzo-a-Pyrene(BaP)was the most toxic monocase as it contributed to 48%?50%of Q_TE concentrations and thus should be given more attention.