河南省武陟县大田土壤重金属形态分布及潜在生态风险评价  

Fractional distribution and ecological risk assessment of heavy metals in farmland soil,Wuzhi,Henan

作　　者：麻冰涓[1] 王海邻[1] 李小超 张永慧 刘军 李东艳[1] 

机构地区：[1]河南理工大学河南省高校矿山环境保护与生态修复省级重点实验室培育基地,河南焦作454000 [2]焦作市环境信息中心,河南焦作454002

出　　处：《安全与环境学报》2015年第4期363-367,共5页Journal of Safety and Environment

基　　金：国家自然科学基金项目(21177035;21377035;41102219);河南省高校矿山环境保护与生态修复省级重点实验室培育基地开放基金项目(KF2014-01)

摘　　要：为了解河南省武陟县大田土壤重金属Cr、Cd、Pb、As、Cu、Se、Ni和Co的形态分布和生态风险情况,在该区域采集了12个表层土壤（0~20 cm）样品,采用修正的BCR连续提取法进行形态分析,探讨其生物有效性,并采用Hakanson指数法评价了重金属的潜在生态风险。结果表明,土壤中不同重金属的形态分布差异很大,其中,Cr、As、Ni和Co均主要以残渣态存在,分别占其总量的66.6%、61.4%、50.7%和41.8%;Cu和Se主要以可氧化态存在,分别占其总量的43.8%和67.8%;Pb主要以可还原态存在,占总量的61.1%;Cd主要以酸提取态存在,占总量的53.3%。生物有效性分析表明,Cd的可利用态K1为0.933,生物有效性是最大的,对土壤生态系统的潜在危害性较大,其次是Pb和Co;Cu和Se在土壤环境发生变化时,很容易再次释放到外界环境中;Cr、As和Ni不易被外界生物利用。潜在生态风险评价结果显示,以国家土壤环境质量标准二级标准为参比值时,Cr、Cd、Pb、As、Cu和Ni的单项潜在生态风险程度均为轻微,综合潜在生态风险处于轻微等级。The paper has collected 12 surface soil samples（ 0-20cm） in hoping to identify and clarify the bioavailability and ecological risk of the heavy metal contaminants in the farmland soil of Wuzhi County,Henan. For our research purpose,we have adopted a modified three-step BCR（ community bureau of reference）extraction procedure to analyze the speciation and bioavailability of such heavy metals as Cr,Cd,Pb,As,Cu,Se,Ni and Co. In this paper,we would like to make assessment of the ecological risk induced by heavy metals in the farmland soil with the potential ecological risk index parameters. As a result,we have observed huge difference in the specific effects of heavy metals on the soil. For example,we have found Cr,As,Ni and Co were mainly laden in the soil as a kind of residual fraction,which account for 66. 6%,61. 4%,50. 7% and 41. 8% of the total soil composition,respectively,whereas Cu and Se were predominately located in the oxidized fraction of the soil,which account for43. 8% and 67. 8% of the corresponding total composition,respectively. Nevertheless,it has been found that Pb has dominantly been released from the reducible fraction（ 61. 1%） while Cd has dominantly been exhausted from the acid-soluble fraction（ 53. 3%） for its own sake. On the other hand,bioavailability analysis reveals that the available fraction（ K1） of Cd is equal to0. 933,indicating a high bioavailability and a serious potential risk for the farmland ecosystem. As to the bioavailability of Pb and Co,they are smaller than that of Cd,Cu and Se in the soil,which tends to be easily released from the soil matrix when the soil＇s environmental conditions have changed. Besides,Cr,As and Ni are generally not bio-available. Therefore,the potential ecological risk caused by using Cr,Pb,As,Cu,Ni and Co to the soil system is low,which indicate somewhat corresponding single potential ecological risk. On the contrary,whereas the potential ecological risk caused by Cd to the soil system is medium,Cd can be identified as the most signi

关 键 词：环境学 农田土壤 重金属 形态分布 生物有效性 生态风险评价 

分 类 号：X53[环境科学与工程—环境工程]