缙云县某复垦地块土壤环境质量调查及生态风险评价

【目的】进一步探索浙江省缙云县某复垦地土壤环境质量。【方法】于2020年在缙云县某复垦地开展土壤环境质量调查，共采集17组土壤-水稻Oryza sativa籽粒复合样品，测定土壤和籽粒中镉、铅、铬、汞、砷等重金属的质量分数，利用单因子污染指数评价法、内梅罗综合指数法、潜在生态风险评价法和生态风险预警指数对土壤重金属污染程度进行评价。【结果】缙云县某复垦地块0～20 cm土层土壤重金属镉、铬、铅、汞、砷质量分数分别为0.33、107.74、53.40、0.03、18.42 mg·kg^-1。其中35.29%的点位土壤砷超标，其余4种重金属均未超过农用地土壤污染风险筛选值，镉、砷平均质量分数高于浙江省土壤背景值。复垦地块个别点位水稻籽粒铬和铅超标。该复垦地块的内梅罗综合污染指数平均值为0.69，有58.82%的点位处于警戒范围；地累积指数从大到小依次为镉(0.08)、铅(0.01)、砷(-0.32)、铬(-0.35)、汞(-3.02)；潜在生态风险指数的平均值为74.10，存在轻微生态风险；土壤生态风险预警指数达到中度预警级别。【结论】复垦地块个别点位水稻籽粒铬和铅超标...

Soil environmental quality investigation and ecological risk assessment of a reclamation land in Jinyun County

  Objective  This study aims to explore the soil environmental quality of a reclaimed land in Jinyun County, Zhejiang Province.  Method  A soil environmental quality survey was carried out in the reclaimed land in Jinyun County in 2020. A total of 17 groups of soil-rice grain composite samples were collected to determine the contents of cadmium (Cd), lead (Pb), chromium (Cr), mercury (Hg), and arsenic (As) in soil and grain. The degree of soil heavy metal pollution was evaluated by single-factor pollution index evaluation method, Nemerow comprehensive index method, potential ecological risk evaluation method and ecological risk early warning index (I_ER).   Result  The contents of Cd, Cr, Pb, Hg, and As in 0?20 cm soil layer of the reclaimed plot in Jinyun County were 0.33 , 107.74, 53.40, 0.03, and 18.42 mg·kg?1, respectively. Among them, arsenic in 35.29% of the points exceeded the standard, and the other four heavy metals did not exceed the screening value of soil pollution risk of agricultural land. The average contents of Cd and As were higher than the soil background value of Zhejiang Province. Cr and Pb contents in rice at some points of the plot exceeded the national standard. The average value of Nemeiro Comprehensive Pollution Index in the study area was 0.69, and 58.82% of the points in the study area were in the alert range. The geo-accumulation index ranging from large to small was Cd (0.08), Pb (0.01), As (?0.32), Cr (?0.35), and Hg(?3.02). The average value of potential ecological risk index (I_R) was 74.10, indicating a slight ecological risk. I_ER reached the moderate early warning level.   Conclusion  Cr and Pb contents exceed the national standard in rice at some points of the reclaimed land. No heavy metals exceeding the standard are observed in soil at any point, but there exists a certain ecological risk. Cd, Cr and Pb are the main ecological risk factors in the study area, which should be paid more attention to in the future. [Ch, 7 tab. 24 ref.]