油田居住区土壤中多环芳烃污染特征与风险评价——以胜利油田为例

Distribution and Health Risks of Polycyclic Aromatic Hydrocarbons in Soils of Residential Areas of an Oil Field:A Case Study on Shengli Oilfield,China

油田城市作为一类与采油厂共同发展起来的特殊城市,长期的原油开采和城市活动导致了其居住区土壤多环芳烃污染特征的特殊性和复杂性。以胜利油田内的居民区土壤为研究对象,调查了城镇、郊区和农村3种不同土地利用类型的45个土壤样品,从污染水平、空间分布和潜在来源等方面阐明了研究区土壤中16种多环芳烃的污染特征,并且根据毒性当量计算了16种多环芳烃的终生癌症风险增量。结果表明:16种多环芳烃总量的浓度范围为16.24~685.2 ng/g,平均为(126.0±158.3)ng/g。在三种土壤类型中,城镇和郊区土壤普遍受到多环芳烃的污染,且主要成分为菲、、芘和荧蒽。在土壤剖面中,表层多环芳烃的浓度水平通常高于底层,该趋势在郊区和城市地区的剖面中尤为明显。通过分析土壤中多环芳烃的特征比值结果以及多环芳烃与总石油烃含量的相关性,揭示了油田居民区土壤中多环芳烃主要来源于石油污染。致癌风险评估结果指出了油田区农村、城郊的表层土壤以及城区的所有土层土壤中的多环芳烃均存在致癌风险,需要研究人员和政府人员对这类地区中的多环芳烃污染开展进一步的监测、分析和管理工作。

Cities in an oil field always share the same history with the crude oil producing factory.There would be a special contamination characteristic of polycyclic aromatic hydrocarbon(PAHs)in soils of residential areas in these cities,because of both petroleum exploitations and urban activities.The residential areas from the Shengli Oilfield were selected as the study area by collecting and analyzing 45 soil samples with 3 different land use types.The contamination characteristics of PAHs were clarified with pollution level,spatial distribution and potential source.The incremental lifetime cancer risk(ILCR)for the 16PAHs was calculated based on the toxic equivalent quantity(TEQ).Results show that the total concentrations of 16PAHs rang from 16.24 to 685.2 ng/g,with a mean of(126.0±158.3)ng/g.Soils in suburban and urban areas are generally polluted by PAHs with the dominant components of phenanthrene,chrysene,pyrene and fluoranthene.The PAH levels are generally higher in the superficial layers than in the deep,especially in profiles from suburban and urban areas.The positive correlation between PAHs and total petroleum hydrocarbons(TPHs)and ratios of individual PAH in the suburban soils both indicate a relatively simple source from petroleum contamination of PAHs.Results of cancer risk analysis suggest relatively high health risks from exposures of PAHs in soils of the surface of rural and suburban areas and whole profiles of urban area,which reveales a potential health risk from PAHs in residential areas of the oil field.