顺德地区土壤重金属污染生态地球化学调查与物源识别

The ecological geochemical survey and source recognition of soil pollution by heavy metals in Shunde area

通过对广东省顺德地区土壤进行1∶5万生态地球化学详查,探讨了该区土壤重金属的来源,并对土壤重金属污染现状作了初步评价。对测区495个样品的测试数据统计分析发现,土壤中Cd、Cu、Pb、Zn、As和Hg含量都明显超出广东省土壤均值,Cd和As分别高出18和6.8倍。根据土地利用方式,将研究区按土地功能分成河道沿岸、工厂用地(包括家具厂和电器厂)、鱼塘基土、居民区四类,计算不同功能区土壤单因子污染指数(Pi)和内梅罗综合指数(P综),重金属平均污染程度为Cd>As>Zn>Cu>Hg>Pb,综合污染指数大小为河道沿岸>家具厂区>居民区>鱼塘基地>电器厂区土。对研究区水样和蔬菜样的分析可知,研究区土—水—植物已全面受到污染。利用Pearson相关分析和主成分分析,Cd、Cu、Pb、Zn相关性高,是典型的铅锌矿组合,主要受自然因素控制,为自然三角洲沉积;As不仅由河流带来,也由工业活动释放出;Hg主要来自人类生活区的各种废弃物堆放。结合土壤自然形态和土地利用类型判断,测区土壤重金属的严重污染和癌症等水土病的高发性,是自然沉积富集和人为工业污染相叠加的两种作用的结果。

Soil survey was conducted in Shunde area with the method of 1 ∶50 000 ecological geochemistry detailed survey to evaluate the source and the current status of heavy metal contamination in soils. A total of 495 samples of soil were collected from Shunde area.The statistical analysis shows that the levels of Cd, Cu, Pb, Zn, As and Hg are obviously higher than their soil average threshold values in Guangdong, implying heavy pollution. The mean values of heavy metals in soil samples exceed the corresponding back?ground values in Guangdong Province. The mean values of Cd and As are 18 and 6.8 times, respectively, as high as the soil back?ground values. According to different determinations, we divided the study area into four parts: river way, industrial soil (including furniture factory and electric appliance), fishpond land and residential area. The pollution index (Pi ) of each metal and the Nemer?ow integrated pollution index (P综) were calculated in the different functional zones. The pollution degree is in order of Cd>As>Zn>Cu>Hg>Pb. The Nemerow integrated pollution indexes of the different areas are in order of river way > furniture factory > residential area > fishpond > electric appliance. Combined with the study of water and vegetables in Shunde area, the authors have revealed that the soil?water?plant system has been contaminated. Using the Pearson??s correlation coefficient and the principal component analysis, the authors have found that there is a significant positive correlation between Cd, Cu, Pb and Zn, which constitute a typical combi?nation of the lead?zinc mine and suggest a delta deposit controlled by natural factors. As comes not only from the river but also from the industrial activity; Hg is mainly derived from anthropogenic source. Combined with the natural mode of occurrence of soil and land?use type, the authors can judge the source of heavy metal in the study area. It is held that the serious contamination of heavy metals and the high adaptive disease in the study area originate from natural depositition and anthropogenic sources.