典型棕地修复前后土壤重金属生态风险变化——以江西贵溪冶炼厂为例

目前,我国对于棕(褐)地周边区域生态风险的研究较少,且主要是针对风险源带来的潜在危害进行评价,没有考虑风险受体能够承受生态风险能力的大小,生态风险评价研究不全面。在棕(褐)地周边区域的生态风险评价中加入风险受体的相关研究,主要从风险源的危害分析和风险受体的生态脆弱性两方面对生态风险进行评价,使评价更加全面,另外,现有研究少有对生态风险在时间上的变化研究,考虑了生态风险时间上的变化,对贵溪冶炼厂周边两个时期的生态风险进行评价并分析其变化,利用GIS软件对评价结果进行空间表达,对研究区域存在的生态风险空间差异进行分析。结果表明:修复前苏门区、九牛岗、水泉区、串山垅等地区存在很强生态风险,沈家-林家区和长塘周家区的生态风险相对较小,处于中等风险水平,修复后研究区的生态风险大大降低,很强风险降为强风险水平,中等风险降为低风险,说明修复方式比较有效,但仍有小范围区域存在较强风险,应加强修复,研究区域中耕地的生态脆弱性最大。对于生态脆弱性较大且生态风险较大的区域应进一步进行修复治理,生态脆弱性大而生态风险较低的地区应加强监测防范,防止再次发生较强风险。

Changes in the ecological risk of heavy metals after soil remediation in a typical Brownfield: A case study of Guixi smelter in Jiangxi Province

To date, few studies have addressed the ecological risk around brownfield areas in China, and most of these studies have only evaluated the potential harm of the risk source, without considering whether the risk receptor can withstand the ecological risk. Therefore, in order to conduct a more comprehensive ecological risk assessment, this paper added the risk receptor analysis in the ecological risk assessment of the area surrounding a brownfield area and ecological risk assessment of the surrounding areas included both hazard analysis of the risk sources and ecological vulnerability analysis of the risk receptors. In addition, few studies have examined the change of ecological risk over time. Therefore, the present study measured ecological risk at two time points. GIS spatial analysis, which was used to determine spatial differences in ecological, indicated that, before remediation, the Sumen area, Jiuniugang, the Shuiquan area, and Chuanshanlong posed a very strong ecological risk, whereas the Shenjia-Linjia and Changtangzhoujia areas posed a medium risk. The ecological risk was greatly reduced following remediation, and the previously very strong-risk areas were reduced to the strong risk level, whereas the medium-risk areas were reduced to the low risk level. This demonstrated the effectiveness of remediation while there were still some regions, even though only a small part, were in strong-risk levels and they should be strengthened to restore in the future. In the present study, the ecological vulnerability of cultivated land was the largest. It is necessary to further remediate some regions which have the strong vulnerability and large risk to improve the ecological levels.Therefore, areas with large ecological vulnerability and low ecological risk should be targeted for improved monitoring and prevention measures, in order to avoid the occurrence of strong risk.