磷石膏堆放场地砷、锌和铅的污染特征分析

The Study of Polluted Characterization on Arsenic, Lead and Zinc in the Vicinity of Phosphogypsum Deposition Site

为了解湖南省郴州市资兴市磷石膏堆放场地周边土壤重金属锌、铅和类金属砷的污染特征,笔者在该场地中进行土壤和地下水采样并进行检测分析。结果表明,调查场地内土壤砷、锌和铅污染主要集中于T19、T20、T21、T28、T29和T30采样点处,As的超标程度和超标率远高于Zn和Pb,且As、Zn和Pb相互之间存在显著正相关。As、Zn和Pb的地累积指数均值均在0~1,调查场地内土壤整体处于轻-中度污染状态。水浸出毒性研究表明,土壤As、Zn、Pb的水浸出浓度随土壤深度的增大而降低,在100~300 cm深度的土壤中超过修复目标值,且As在700~900 cm的深度也超过修复目标值,土壤物化性质、历史污染状况以及地下水作用共同影响了重金属在垂直剖面上的分布。因而,本调查有助于在土壤修复时根据土壤局部污染状况进行有针对性的修复工作。

To investigate the pollution pattern of Zn, Pb and metalloid As in the vicinity of phosphogypsum deposition site in Zixing, Chenzhou, Hunan Province, soil and underground water samples were collected and analyzed. Results showed that contamination by As, Zn and Pb was most serious in sampling points T19, T20, T21, T28, T29 and T30. The geoaccumulation index of As, Zn and Pb range from 0 to 1, indicating that the investigated sites was slightly to moderately contaminated. According to water leaching toxicity experiment, leaching concentration of soil As, Zn and Pb decreased with increased soil depth but was above the target concentration for remediation at 100-300 cm soil depth for the three heavy metals and also 700-900 cm for As. Vertical distribution of soil heavy metals could be attributed to the combined effects of soil physciochemical properties, historical contamination and the influence of underground water. Therefore, this investigation will shed light on more specific soil remediation of the site partially contaminated by heavy metals.