陕西省1800份农村土壤样品重金属监测结果分析

目的 掌握陕西省农村土壤卫生状况，为下一步开展土壤污染风险管控和土壤修复提供科学依据。方法 于2016 - 2018年累计对陕西省90个涉农区县的农田土壤开展现场调查和重金属铅、铬、镉、汞和砷的含量检测。数据按照关中平原、陕北高原和秦巴山区分别统计、分析与评价。结果 3年累计采集监测土壤样品1 800份，土样整体达标率为93.17%，陕北高原土样整体达标率(98.82%)分别高于关中平原 (95.22%)和秦巴山区(86.43%)（P＜0.001）。全省土样中铅的达标率为99.56%。土样中铬的达标率为99.83%，铬超标土样全部来自秦巴山区。土样中镉的达标率为93.78%，关中平原（95.44%）和秦巴山区（87.86%）土样中镉的达标率较低，秦巴山区存在3份镉高风险土样。土样中汞的达标率为99.72%。土样中砷的达标率为99.89%，砷超标土样全部来自关中地区。结论 陕西省土壤中重金属铅、铬、汞和砷的污染水平较低，局部地区重金属镉的污染较为严重，3个地区土壤状况呈现明显的地区特征。

Analysis of monitoring results of heavy metals in 1800 rural soil samples in Shaanxi Province

Objectives The study aimed to assess the status of farmland soil sanitation in rural area of Shaanxi, so as to provide scientific basis for the next step of soil pollution risk control and remediation. Methods From 2016 to 2018, field investigation of farmland soil and analysis of heavy metal lead, chromium, cadmium, mercury and arsenic in soil in 90 agricultural counties in Shaanxi were conducted. The data were statistically analyzed and evaluated according to the northern, central and southern regions. Results A total of 1800 rural soil samples were monitored in three years. The qualified rate of soil samples was 93.17%. The qualified rate of soil samples in northern region of Shaanxi was 98.82%, which was significantly higher than that in central (95.22%) and southern regions (86.43%) (P<0.001). The qualified rates of heavy metal lead and chromium in soil samples in Shaanxi were 99.56% and 99.84% respectively. The soil samples of heavy metal chromium exceeding the standard were all from the southern region. The qualified rate of heavy metal cadmium in soil samples in Shaanxi province was 93.78%. The qualified rate of heavy metal cadmium in the soil samples of the northern region was 99.12%, which was significantly higher than that in the central (95.44%) and southern (87.86%) regions (P<0.001). Three high-risk cadmium soil samples existed in southern region. The qualified rates of heavy metal mercury and arsenic in soil samples in Shaanxi were 99.72% and 99.89% respectively. The soil samples of heavy metal arsenic exceeding the standard were all from the central region. Conclusion The pollution level of heavy metals such as lead, chromium, mercury and arsenic in farmland soil of Shaanxi was low. Cadmium pollution in the central and southern regions was more serious. The farmland soil pollution in three regions of Shaanxi showed obvious regional characteristics.