浑蒲灌区土壤中多环芳烃的分布及生态响应

Distribution and Risk Assessment of Polycyclic Aromatic Hydrocarbons in Soils in Hunpu,Liaoning,China

因污水灌溉、大气沉降和油井的直接输入可能导致浑蒲灌区土壤中的w（PAHs）升高．沿灌渠走向选取了8个采样点和1个对照点，分析了不同深度的土壤中w（PAHs）和表层土壤中微生物PLFAs（磷脂脂肪酸）的组成．Spearman分析表明，除了芴和葸，其他PAHs、2—6环PAHs和总PAHs的质量分数均与土壤深度呈显著负相关．油井附近的旱田土壤中ω（PAHs）较高[I-2U采样点为（645．77±204．21）μg／kg，I-6U采样点为（660．39±208．83）μg／kg]；浑蒲灌区土壤中的PAHs以低环数的菲[（61．92±13．72）μg／kg]、蒽[（39．11±10．68）μg／kg]和芴[（31．12±8．14）μg／kg]为主；由于淋洗作用，水田土壤中ω（PAHs）明显低于旱田．相比对照点，浑蒲灌区土壤中微生物量降低，但微生物多样性增加．通过对PLFAs的主成分和聚类分析，受油井影响的水田（I-1P、I-5P采样点）与旱田（I-2U和I-6U采样点）聚在一起，与对照点距离较远，说明油井附近水田和旱田的微生物结构与对照点存在显著差异，二者同时受到了油田的影响，相应的生态功能也会受到同样的影响．尽管水田土壤中w（PAHs）明显低于旱田。但其土壤微生物结构也明显受到了石油污染的影响，而且水田地下水健康风险增加，因此建议关注水田风险，并为水田和旱田制订不同的PAHs土壤基准值．

Concentrations of PAHs have increasee in soils in the Hunpu region due to wastewater irrigation, atmospheric deposition, and oil wells. Eight soil units were sampled along the strike of irrigation canals in the Hunpu region, and a control soil unit was sampled as well. Concentrations of PAHs at different depths and phospholipid fatty acids in the surface soil were analyzed. Spearman analyses showed that all PAHs （ except Fie and Ant）, 2- to 6- ring PAHs, and ∑ PAHs exhibited significantly negative relation with depth （ P 〈 0.05 ）.High-concentrations of PAHs were found in the upland fields near oil wells （ I -2U （645.77 ± 204. 21 ） μg/kg, I -6U （660. 39 ± 208. 83） μg/kg）. Low ring number PAHs （phenanthrene （61.92 ± 13.72） μg/kg, anthracene （39.11 ± 10. 68） μg/kg, and fluorine （31.12 ± 8.14） μg/kg） were dominant in the farmland soil. Downward migration of PAHs to groundwater resulted in lower concentrations of PAHs in paddy fields. The microbial biomass decreased with the increase of microbial diversity in the Hunpu region relative to the control. The paddy fields （ I -1P and I -SP） and the upland fields （ I -2U and I -6U） affected by oil wells were gathered together through principal component analysis and cluster analysis on the basis of phospholipid fatty acids, which were differentiated from the control. The results indicate that the microbial composition in both the upland and paddy fields close to the oil wells were significantly different from those in the control sites. The microbial community and corresponding ecological function in both the upland and paddy fields were affected by the nearby oil wells. Moreover, concentrations and risks of PAHs were higher in the groundwater from paddy fields. The risks posed by PAHs in soil in the paddy fields should be paid attention to by environmentalists and the government. Basic soil quality criteria for different PAHs should be established for upland and paddy fields.