沉积物重金属累积特征与区域经济发展的响应关系

RESPONSE RELATIONSHIP BETWEEN ACCUMULATION CHARACTERISTICS OF HEAVY METALS IN SEDIMENTS AND REGIONAL ECONOMIC DEVELOPMENT

为阐明社会经济发展对沉积物重金属浓度变化的驱动作用,研究基于洞庭湖流域2003—2017年的主要社会经济指标和沉积物重金属数据,采用潜在生态风险评价指数法对沉积物重金属污染风险进行评价,结合EKC模型反映目前经济发展与洞庭湖沉积物重金属之间的宏观关系,并建立洞庭湖流域主要社会经济指标与重金属污染的响应关系。结果表明:随着洞庭湖经济的增长,洞庭湖沉积物重金属污染问题突出,其中Cd污染最严重,均值为3.83 mg/kg,其次是Hg,均值为0.20 mg/kg;潜在生态风险评价结果表明:Cd、Hg的风险最高,2种金属风险贡献率高达92.25%,为主要污染元素;基于EKC模型拟合结果可知,沉积物重金属整体污染程度及其生态风险将持续加剧;而工业发展、有色矿产资源的开发利用和旅游业等第二、三产业发展对Cd、Hg的影响显著。因此,严格控制第二、三产业发展过程中入湖污染物的重金属含量是减少洞庭湖沉积物重金属污染的关键。

The purpose of this study was to elucidate the driving effect of socio-economic development on the change of heavy metal concentration in sediments.The main socio-economic indicators and sediment heavy metals contents of Dongting Lake basin from 2003 to 2017 were used as the basis of this study.Then the potential ecological risk assessment index method was used to evaluate the risk of heavy metal pollution in sediments,and EKC model was used to reflect the macro-relationship between economic development and heavy metals in Dongting Lake sediments.Moreover,the response relationship between major socio-economic indicators and heavy metal pollution in Dongting Lake basin was established.The results showed that the pollution of heavy metals in Dongting Lake sediments was becoming more and more serious with the economic growth of Dongting Lake.Cd pollution situation was the most serious,with an average value of 3.83 mg/kg,followed by Hg,with an average value of 0.20 mg/kg.Potential ecological risk assessment results showed that Cd and Hg were the main pollution elements,which had high risk and the contribution rate of the two metals was 92.25%.The overall pollution degree and ecological risk of heavy metals in sediments would continue to increase,which could be seen from the fitting results of EKC model.Industrial development,exploitation and utilization of non-ferrous mineral resources and the development of secondary and tertiary industries such as tourism industries had significant effect on Cd and Hg.Therefore,the key to reducing heavy metal pollution in Dongting Lake sediments was to strictly control the heavy metal content of pollutants entering the lake during the development of the secondary and tertiary industries.