采样位置与时间选择对土壤重金属风险评估工作的影响

Influence of sampling location and time selection on risk assessment

中文关键词:  风险评估  铜  铅  土壤  横向迁移

英文关键词:risk assessment  Cu  Pb  soil  lateral migration

中文摘要:

      目的 建立一种具有代表性且能够综合、准确反映多种重金属元素在土壤中污染状况的样品采集方法, 为土壤重金属风险评估工作的顺利展开提供有力的保障。方法 模拟铜、铅2种元素在土壤中的迁移条件, 结合试验田铜元素、铅元素的背景值, 分别添加Cu(NO3)2、Pb(NO3)2, 使试验田中心污染源铜元素和铅元素的分别达到2.6×103 mg/kg和4.0×103 mg/kg。设置3组不同的灌溉量, 每组设2个平行试验, 分别于d 7、14、31、49进行采样, 之后利用电感耦合等离子体发射光谱仪(ICP-OES)、原子吸收分光光度计检测这2种重金属元素含量, 研究铜、铅在土壤中的迁移规律。结果 检测结果显示铜、铅2种元素在土壤中的横向迁移速度差异较大。铜元素横向扩散速度较快, 在d 49时监测位点的铜元素浓度趋于稳定, 接近最大值; 而铅元素较慢, 监测位点的铅元素浓度基本没有发生变化。结论 单一的取样点难以同时满足铜、铅2种重金属元素的风险评估工作需要, 建议对这2种重金属元素的取样检测工作应尽量区别开展。

英文摘要:

      Objective To establish a kind of representative, comprehensive and accurate sampling method which can reflect the diversity of heavy metals pollution in soil and provide an effective protection for the well proceed of risk assessments of heavy metals in soil. Methods The migration of Cu and Pb in soil were simulated. Cu(NO3)2 and Pb(NO3)2 were added into the testing field according to the background values of Cu and Pb, to make the concentration of Cu and Pb in the center of testing field reach 2.6×103 mg/kg and 4.0×103 mg/kg respectively. Three groups were set with different irrigation amounts, two parallel tests were included in each set, and the soil samples were collected at d 7, 14, 31 and 49. The content of the two heavy metals were detected by inductively coupled plasma atomic emission spectroscopy (ICP-OES) and atomic absorption spectrophotometer. Results The results showed that the lateral migration speed of these two elements in soil were quite different. The lateral diffusion speed of Cu was fast, but its concentration was stabilized and get close to the maximum at d 49 at monitoring sites; whereas the lateral diffusion speed of Pb was very slow, and its concentration did not change significantly at monitoring sites. Conclusion It is difficult to meet the risk assessment requirements of Cu and Pb with a single sampling point, so this paper recommends the sampling inspection of these two heavy metals should be carried out respectively.