摘要:为明确黄河三角洲石油开采区表层土壤和玉米中多环芳烃（PAHs）的含量及其污染水平，采集农田土壤和玉米各71个样品，检测农田土壤和玉米各部位中16种PAHs含量，并采用内梅罗指数法和健康风险评价模型评估了农田土壤中多环芳烃的生态健康风险。结果表明，农田土壤、玉米根、茎和叶中多环芳烃的含量分别为256.6-1936、291.4-680.9、324.9-527.9、289.5-2400 μg/kg。农田土壤中多环芳烃以4-6环为主。多环芳烃在玉米根茎叶富集系数大小排序为：叶 > 茎 > 根。玉米不同组织中PAHs浓度与相应农田土壤中PAHs浓度的进行相关分析结果表明，农田土壤中PAHs含量与玉米根、茎中PAHs含量均存在极显著正相关关系，相关系数分别为0.98（P<0.01）、0.98（P<0.01），表明玉米根和茎的多环芳烃主要来源于农田土壤中，农田土壤中PAHs的含量影响着PAHs在玉米根茎中的积累和分布。玉米叶中PAHs含量与农田土壤中PAHs含量与玉米根、茎中PAHs含量不存在相关关系，表明玉米叶中多环芳烃并非来自土壤中PAHs的迁移，可能来源于大气。内梅罗指数结果表明，农田土壤PAHs达到了中度污染，其中BaA、Pyr和BbF达到了偏重污染；健康风险评价结果表明，农田土壤PAHs对儿童和成人的平均非致癌风险分别为0.44和0.12（均小于1），表明农田土壤多环芳烃对成人和儿童的非致癌风险是可接受；农田土壤PAHs对儿童和成人的平均致癌风险分别为3.6×10^-5、9.0×10^-6，没有超过致癌风险水平上限（10^-4），致癌风险尚在可接受范围内。3种暴露途径中，皮肤接触是土壤PAHs的最主要暴露方式，其次是经口摄食，吸入暴露途径甚微，可忽略不计。PAHs对儿童健康的威胁风险要大于成人，所以应尽可能避免儿童直接接触或误食土壤等其他介质的污染物。



Abstract:To investigate the residual levels of polycyclic aromatic hydrocarbons (PAHs) in topsoil and corns in the Yellow River Delta oil extraction area, total 71 samples of farmland soils and 71 samples of corns were collected. The content of 16 PAHs in soils and spinach were detected. The Nemerow pollution index method and the health risk assessment model were used to assess the ecological health risks of PAHs in farmland soil. The results showed that the contents of PAHs in farmland soil, corn roots, stems, and leaves were 256.6-1936 μg/kg, 291.4-680.9 μg/kg, 324.9-527.9 μg/kg, and 289.5-2400 μg/kg, respectively. The results showed that PAHs in farmland soils were dominated by 4-6 rings. The order of PAHs enrichment coefficients in root, stem and leaf was leaf > stem > root. The correlation analysis results of the PAHs concentration in different corn tissues and the PAHs concentration in the corresponding farmland soil showed that there was very significantly positive correlation between the PAHs content in the farmland soil and the PAHs content in the corn root and stem, and the correlation coefficients were 0.98 (P<0.01), 0.98 (P<0.01), respectively. It indicates that the PAHs of corn roots and stems are mainly from farmland soil, and the content of PAHs in farmland soil affects the accumulation and distribution of PAHs in corn roots and stems. There is no correlation between PAHs content in corn leaves and PAHs content in farmland soil and PAHs content in corn roots and stems, which indicating that PAHs in corn leaves do not come from the migration of PAHs in soil, but may come from the atmosphere. The Nemerow index results showed that the PAHs in farmland soils have reached moderate pollution, and BaA, Pyr, and BbF have reached heavy pollution. The health risk assessment results showed that the average non-carcinogenic risk of PAHs in farmland soils to children and adults was 0.44<1, 0.12 <1, indicating that the non-carcinogenic risk of PAHs in farmland soils is acceptable for adults and children. The average carcinogenic risk of PAHs in farmland soils for children and adults was 3.6×10^-5 and 9.0×10^-6, respectively, which was less than the upper limit of acceptable cancer risk of 10^-4. Among the three exposure routes, skin contact is the most important way of exposure to soil PAHs, followed by oral ingestion, and the inhalation exposure route is negligible. The risk of PAHs to children's health is greater than that of adults, so it is necessary to avoid children's direct contact with or ingestion of soil and other pollutants by mistake.





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