沈抚灌区土壤重金属污染健康风险初步评价

Preliminary Health Risk Assessment of Heavy Metals in Soil in Shen-fu Irrigation Area

采用现场采样及室内测试方法对沈抚灌区农田土壤中Cu、Hg、Ni和Cd等重金属的含量进行了测定分析,利用污染指数法对灌区土壤环境质量进行了评价,并应用美国环保局推荐的健康风险评价模型对灌区土壤重金属通过土壤摄食途径所引起的健康风险作了初步评价。结果表明,灌区土壤中重金属的平均浓度范围分别为Cu:22.1～40.8mg·kg-1,Hg:0.036～0.310mg·kg-1,Ni:29.8～44.4mg·kg-1,Cd:0.145～0.956mg·kg-1。4种重金属浓度平均值大小为Ni>Cu>Cd>Hg;土壤中Cu、Hg、Ni和Cd所引起的成人和儿童的平均个人风险均低于可接受水平10-6,且在这两类调查人群中,健康风险大小顺序均为Cd>Ni>Hg>Cu;儿童比成人更易受到土壤重金属的影响,致癌风险是成年的3倍;灌区土壤环境质量环境评价结果显示,灌区土壤重金属污染处于轻微水平。

As the largest oil-eontaining wastewater irrigation area in northeast China, Shen-fu wastewater irrigation area has been the research focus on organic pollutants. However, rare study on heavy metals in this area has been reported. In this study, concentrations of Cu, Hg, Ni and Cd in soil in this area were analyzed, soil environmental quality was evaluated with the combination of single pollution index and eomprehensive pollution index, and health risks of Cu, Hg, Ni and Cd caused by soil ingestion were assessed using USEPA health risk assessment model. Soil samples were taken from farmland soils in irrigation area. The results showed that the eoncentrations of Cu, Hg, Ni and Cd in soil ranged from 22.1-40.8 mg·kg^-1 for Cu, 0.036-0.310 mg·kg^-1 for Hg, 29.8-44.4 mg·kg^-1 for Ni, 0.145-0.956 mg·kg^-1 for Cd. The average concentrations of Cu, Hg, Ni and Cd followed the order： Ni〉Cu〉Cd〉Hg; Concentrations of heavy metals in this research were below the grade Ⅱ national soil quality standard except Cd. Soil environmental quality assessment in Shen-fu irrigation area showed that pollution caused by heavy metals in soil in this irrigation area was at a low level. The average individual health risks of heavy metals for children and adult were all lower than the acceptable risk level 10^-6, the health risk order was Cd〉Ni〉Hg〉Cu; Cancer risk for children was 3 times of adult. Children were more easily affected by soil heavy metals than adults, for they may ingest more soil in their daily life.