湖南长株潭中度污染区土壤镉概率生态风险评价

湖南长株潭地区土壤修复试点工作已经开展,但并未关注重金属镉对生态系统的威胁,尤其是继续进行作物种植的中度污染区。文章选取长株潭地区三个县的中度污染区为研究区域,结合文献调研,利用美国ECO-TOX数据库获取了共计28个本地物种两个层次的毒性数据,利用物种敏感度分布(Species sensitivity distribution,SSD)模型和联合概率曲线(Joint probability curve,JPC)方法开展中度污染区的概率生态风险评价研究。结果表明,在LC/EC/IC水平50下,A县、B县、C县的概率生态风险值依次为1.65%、3.40%、5.80%;在NOEC/LOEC水平下,A县、B县、C县的概率生态风险值依次为7.46%、12.97%、19.50%。该结果说明,长株潭地区中度污染区土壤中重金属镉对生态系统具有一定的风险作用,同时该结果为生态系统保护目标制定提供科学依据。

Probabilistic Ecological Risk Assessment of Cadmium in the Soils of Changsha-Zhuzhou-Xiangtan Area of Hunan Province

Although the pilot project of soil remediation was carried out in the Changsha-Zhuzhou-Xiangtan (CZX) area of Hunan Province,the threat of cadmium to the ecosystem was not considered at all,especially in the moderate pollution area with continuous crops growth.In this paper,the moderate polluted areas in three counties were taken as study areas.On the basis of literature review,by use of the ECO-TOX database developed by USEPA,28 toxic data of native species in two levels were collected.Then,probabilistic ecological risk of cadmium was assessed by utilization of species sensitivity distribution (SSD) models and joint probability curves (JPC).The results showed that under the level of LC/EC/IC50,the probabilistic ecological risk of county A,B and C was 1.65％,3.40％ and 5.80％ respectively;and under the level of NOEC/LOEC,the probabilistic ecological risk of county A,B and C was 7.46％,12.97％ and 19.50％ respectively.The results revealed that cadmium in the soils of the moderate pollution areas of CZX area had certain ecological risk to the ecological system.At the same time,the results also provided scientific basis for ecosystem protection goal development.