环渤海地区土壤重金属富集状况及来源分析

土壤是人类赖以生存的基本要素和重要资源.人类活动导致大量重金属富集于土壤中,引起土壤质量下降并通过食物链逐级富集,直接危害人类健康.本研究以环渤海地区农田土壤为例,收集公开发表的数据建立环渤海地区土壤重金属数据库并进行整合分析,计算环渤海地区8种土壤重金属含量,评估重金属的富集程度,预测其生态风险,并探讨重金属的主要来源,旨在为该区域土壤重金属污染防控、治理提供重要信息.结果表明,环渤海地区土壤Cu、Zn、Pb、Cd、Cr、Hg、As、Ni的含量分别为27.7、71.7、25.1、0.4、57.4、0.1、9.2、25.3 mg·kg~(-1),其中,Cu、Pb、Cd、Hg 4种重金属含量高于中国土壤元素背景值,且Cd、Hg的累积量较大.内梅罗污染指数结果显示,研究区域11.9%的土壤已有重金属污染,另有13.5%的土壤处于重金属污染警戒范围内.Hankanson生态风险评估结果表明,Cd和Hg为中等生态风险,其余重金属为轻度生态风险,25.9%的案例为中度生态风险状态,有少部分案例(3.7%)达到强度生态风险.利用多元统计方法分析重金属来源的结果显示,Zn、Cr、Ni、As主要来源于成土母质;Cu、Pb、Cd、Hg主要受以工业生产、农业活动及交通排放为代表的"人为源"影响.

Concentration, risk assessment and sources of heavy metals in soil around Bohai Rim

Soil is the basic material and important resources for human. A large amount of heavy metals has been enriched in soil caused by human activities, which has induced the deterioration of soil quality and enrichment of heavy metal through the food chain, directly threatening human health. Base on the data collected from documents, concentrations of Cu, Zn, Pb, Cd, Cr, Hg, As and Ni in the top soils of farmland in Bohai Rim region of China were calculated, meantime, the extent of heavy metal pollution and the sources of heavy metal were also analyzed. The results showed the concentration of Cu, Zn, Pb, Cd, Cr, Hg, As and Ni were 27.7, 71.7, 25.1, 0.4, 57.4, 0.1, 9.2 and 25.3 mg·kg^-1, respectively. Compared the results with the back ground value of Chinese soil elements, these data indicated that Cu, Pb, Cd, Hg were enriched, especially for Cd and Hg. Nemerow assessment showed 11.9% of farmland soil in Bohai Rim region suffered from heavy metal pollution, and other 13.5% of the soil will face pollution if there is no control of heavy metal emissions. Hankanson ecological risk assessment showed all of the heavy metal belong to low pollution risk except for Cd and Hg;Light ecological risk, middle ecological risk and strong ecological risk were 70.3%, 25.9% and 3.7% of study cases we collected in Bohai Rim region, respectively. Principal component analysis (PCA) and cluster analysis (CA) showed that Zn, Cr, Ni and As were from the natural background; Cu, Pb, Cd and Hg were greatly influenced by human activities, such as industry, agriculture, and traffic.