福建省龙海市南部表层土壤重金属元素累积特征研究

Study on accumulation characteristics of heavy metal elements in topsoil of southern Longhai City,Fujian Province

基于2004年和2015年福建省龙海市南部表层土壤获得的重金属元素和pH值测试数据,采用数理统计方法分析该区土壤Cd、Hg、Pb、As、Cu、Zn及pH值等指标的累积变化特征及影响因素。龙海市南部表层土壤Cd、Cu、As等重金属元素呈一定程度的正累积趋势,其中As和Cu的平均相对累积率分别为4.943%和5.486%;Hg呈明显贫化趋势,平均相对累积率为-12.833%;pH值呈显著酸化趋势,在研究区不同土壤中具有一定的差异性;Pb、Zn变化不显著。研究区玄武岩地质背景区平均累积率较高的元素最多,主要为Cd、Pb、As;中酸性火山岩地质背景区平均累积率较低的元素最多,主要为Cu、Pb、Zn、As;园地土壤平均累积率总体较高的元素最多,主要为Cd、Pb、As、Hg;耕地土壤平均累积率较低的元素最多,主要为Cd、Cu、As、Hg。此外,人类活动也是造成龙海市南部土壤重金属元素累积或贫化的重要因素。

Based on the test data of the heavy metal elements contents and pH values obtained in topsoil of southern Longhai City,Fujian Province in 2004 and 2015,the cumulative change characteristics and influencing factors of Cd,Hg,Pb,As,Cu,Zn and pH values over the past 11 years were analyzed by mathematical statistics method.The result shows that the content of Cd,Cu,As and other heavy metal elements showed a positive accumulation trend to a certain extent in southern surface soil of Longhai City,among which the average relative accumulation rates of As and Cu were 4.943%and 5.486%respectively,Hg showed a significant dilution trend with the average relative accumulation rate was-12.833%.The pH values showed a significant trend of acidification,which showed a certain difference among different soils in the study area.Besides,the changes of Pb and Zn were not significant.It is concluded that elements with high average accumulation rate in basalt background area of the study area are the most,such as Cd,Pb and As,elements with low average accumulation rate in the background area of intermediate-acid volcanic rock are the most,such as Cu,Pb,Zn and As,and elements with higher average soil accumulation rate in the garden are the most,such as Cd,Pb,As and Hg,while elements with low average accumulation rate in cultivated land are the most,such as Cd,Cu,As and Hg.In addition,human activity is also an important factor causing the accumulation or depletion of heavy metals in topsoil of southern Longhai City.