山西省典型燃煤污染区土壤中多环芳烃风险评价

摘要

To investigate the pollution, ecological risk and health risk of PAHs, GC-MS was adopted to analysis the concentration of 16 priority polycyclic aromatic hydrocarbons (PAHs) which were measured in 128 surface soil samples from typical coal-fired pollution region in Shanxi Province. The results showed that the total mass concentration of these PAHs were (723.2±1230) μg·kg-1. Four to six rings PAHs contributed most of total PAH burden. According to Maliszewska-Kordybach's classification standards of soil contamination, 78.12% of samples were contamined in different degree. Based on Nemerow Pollution Index, the classification evaluation showed that 83.59% soil samples were polluted. Gucheng Town and Xincheng Town were the most heavily polluted area, over 60% soil samples were heavily polluted by PAHs. Considering the different toxicity in PAHs monomer, toxic equivalence factors (TEFs) were used for valuing PAHs ecological risk. The results showed Bap toxic equivalent quantity (TEQBap) of 10 PAHs in the Dutch soil standard were (67.50±137.7) μg·kg-1, 42.19% of samples in which were higher than Dutch target values. Gucheng Town and Xincheng Town were the most heavily toxic contamination area, exceed multiple was above 3 times, averagely. Both for adult and children, PAHs in the soil of studied region were unlikely to pose a significant non-carcinogenic risk. Moreover, the total cancer risk (CKtotal) exceeded acceptable levels (10-6) in Gucheng, Xincheng , suggesting the soil PAHs of these areas may cause harm to human health and should be paid more attention.%在山西省临汾市南部燃煤污染代表性区域(1034 km2)采集了128个表层土壤样品,采用气相色谱-质谱联用技术(GC-MS)分析了土壤中16种优控多环芳烃(PAHs)的含量,并对样品中PAHs的生态风险和人体健康风险进行了评价.结果显示,16种PAHs的质量分数为(723.2±1230)μg·kg-1,组成成分以4~6环为主.根据Maliszewska-Kordybach分级评价标准,研究区域土壤中78.12%的样品受到PAHs不同程度的污染.基于内梅罗综合污染指数法评价结果,研究区域83.59%的样点存在PAHs污染,其中古城镇和新城镇60%以上的采样点达到了重度污染级别.基于毒性当量因子(Toxic Equivalency Factor,TEF)风险评价法的生态风险评价结果显示,荷兰土壤质量标准所涉及到的10种PAHs的苯并(a)芘(Bap)毒性当量浓度(Bap toxic equivalent quantity,TEQBap)为(67.50±137.7)μg·kg-1,其中42.19%的样点超过荷兰土壤TEQBap10的标准限值,古城镇和新城镇土壤中PAHs平均超标3倍以上.对研究区域的暴露人群分别进行非致癌风险及致癌风险评价,结果显示研究区域土壤中的PAHs不会对成人和儿童产生明显的非致癌风险.而在古城镇、新城镇、陶寺乡、景毛乡和永固乡,土壤中PAHs引起的综合致癌风险已超过可接受致癌风险(10-6),对人群健康构成了潜在威胁,需引起重视;其他研究区域的致癌风险仍在可接受范围(10-6)之内.