铅锌冶炼区农田土壤中多环芳烃污染特征、源解析和风险评价

Characteristics, sources apportionment and risk assessment of polycyclic aromatic hydrocarbons in agricultural soils from zinc smelting area,Guizhou Province

采用快速溶剂萃取(ASE)、凝胶渗透色谱净化(GPC)协同高效液相色谱(HPLC)检测方法,分析贵州省典型铅锌冶炼区赫章县41个表层农田土壤样品中16种优控多环芳烃(PAHs)的含量水平,并对其污染特征、来源和生态风险进行了分析.结果表明:典型铅锌冶炼区妈姑镇农田土壤∑PAHs的含量范围为196~11592μg·kg^(-1),算术均值和中位值分别为1500μg·kg^(-1)和780μg·kg^(-1),妈姑镇高含量的∑PAHs积累可能与当地长时间的铅锌冶炼活动有关.PAHs组分特征表现出以2~3环和4环多环芳烃为主.根据荷兰土壤干预值,妈姑镇农田土壤96.6%受到了不同程度的污染,其中,轻微污染、中度污染和重度污染所占比例分别为31.0%、24.1%和41.5%.研究区域PAHs的主要来源为煤和生物质的不完全燃烧及石油源.妈姑镇的新厂村、何家冲村、平桥组、拱桥村及赫章县的达依乡采样点土壤中PAHs的TEQBap10超过了荷兰土壤干预值规定的TEQBap10限值33.0μg·kg^(-1),说明赫章县、尤其是赫章县典型铅锌冶炼区妈姑镇农田土壤已受到PAHs的污染,存在潜在的生态风险.

The concentrations of 16 polycyclic aromatic hydrocarbons（ PAHs） of 41 agriculture soil samples（ 0 - 20 cm） collected from a long-term zinc smelting area in Guizhou were analyzed by high performance liquid chromatography（ HPLC） combined with accelerated solvent extraction（ ASE） and gel permeation chromatography（ GPC） purification. Characterization,source apportionment and risk assessment of PAHs in soils were conducted. The total concentrations of 16 PAHs（ ∑ PAHs） were 196 - 11592 μg·kg-（-1）,with mean and median concentrations of 1500 μg·kg-（-1） and 780 μg·kg-1,respectively. The high concentration of ∑PAHs in soils was closely associated with the zinc smelting activities. The dominant compounds were 2 - 3 ring and 4 ring PAHs. 96.6% of the soils in the study area were contaminated with PAHs with 31. 0% in the slight contamination category,24. 1% in themoderate contamination category and 41. 5% in the heavy contamination category. PAHs in soils from the study area mainly came from combustion of biomass,coal,and oil. The Bap toxicity equivalent quantity for 10 PAHs（ TEQBap10） in soils collected from the village of Xinchang,Hejiachong,Pingqiao,Gongqiao and Dayi exceeded the Dutch soil intervention value of 33.0 μg·kg-（-1）,suggesting that PAHs in the study area might pose potential risks to ecological receptors.