机构地区:[1]中国农业大学资源与环境学院,北京100193 [2]新疆大学资源与环境科学学院,乌鲁木齐830046 [3]智慧城市与环境建模自治区普通高校重点实验室,乌鲁木齐830046 [4]新疆大学绿洲生态教育部重点实验室,乌鲁木齐830046
出 处:《地球与环境》2019年第4期485-494,共10页Earth and Environment
基 金:国家自然科学基金(41762019);博士启动基金(BS160232);大学生创新训练项目(201710755099)
摘 要:为了认识蔬菜产地土壤重金属富集现状,探索其解决途径,为污染防治措施提供科学依据,促进无公害蔬菜生产,确保蔬菜质量安全.在乌鲁木齐北郊蔬菜地采集26个土壤样品和7个水体样品,分别测定样品中Hg、As、Cr、Cd、Pb和Zn 6种重金属的含量.采用地积累指数(Ige.)、污染负荷指数(PLI)、潜在生态风险评价(RI)对蔬菜地土壤重金属污染及潜在生态风险进行分析.通过土壤与水样的结合,采用主成分分析法进行污染来源分析,结果表明:(1)乌鲁木齐安宁渠蔬菜基地土壤中Hg、Cr和Zn重金属含量的均值分别为新疆土壤背景值的5.74、1.74、1.52倍,其中Cd含量的均值是国家二级标准的2.69倍.地下水中Cr含量均值超过国家灌溉水限制标准,是其8.89倍.(2)6种重金属Ig..的平均值依次为Cd>Hg>Cr>Zn>As>Pb,其中Cd属于中-强度污染,H-g为中度污染,Cr为轻度污染,Zn、As和Pb均为清洁水平.研究区土壤区域污染负荷指数PLIzone为1.91,属于中度污染,其中Cd的贡献率最大,为56%,其次是Hg,贡献率为22%.土壤RI均值为673.1,属于严重潜在生态风险态势.(3)研究区土壤Pb、Cr和Zn,主要来自交通和农业活动等人为污染,As、Cd主要受自然母质和大气沉降的影响.该蔬菜基地潜在生态风险主要来自Cd和Hg,建议在农业生产中防范Cd、Hg的污染.The objectives of this study were to systematically investigate the pollution status of heavy metals in soil,identify possible pollution sources and determine the potential ecological risk of heavy metals in the Anningqu vegetable base in Urumqi.Twenty-six soil samples and seven water samples were collected from different sites in the Anningqu vegetable base,and their contents of six heavy metals(Hg、As、Cr、Cd、Pb and Zn)were determined.The obtained data were analyzed statistically by methods of geo-accumulation index,pollution load index and potential ecological risk assessment and the potential major pollution sources were determined by the principal component analysis method.The results indicated:1)The mean concentration of Cd in soil samples was 2.69 times higher than its National Second-grade Standard,the mean concentrations of Hg,Cr and Zn were 5.74,1.74 and 1.52 times,respectively,higher than their soil background values in Xinjiang,and the mean concentrations of As and Pb were lower than their corresponding background values;the average concentration of Cr in irrigation water samples was 4.51 times higher than its national irrigation water standard.(2)The average Igeo values of six heavy metals in soil followed a trend of Cd>Hg>Cr>Zn>As>Pb,and indicated that the pollution status of Cd was moderate to heavy,the pollution status of Hg was moderate,the pollution status of Cr was slight and the pollution status of other three metals was none.The PLIzone value of the study area was 1.90,indicating a moderate pollution,in which Cd contributed 56%the most,Hg contributed 22%the second.The average RI value of soil was 673.1,indicated a serious potential ecological risk.(3)Pb,Cr and Zn contents in soil of the vegetable base were mainly controlled by human activities,and As and Cd contents in soil of the vegetable base were mainly affected by complex pollution sources.The pollution of Cd and Hg should be concerned in agricultural production processes since they are major elements of causing ecological risks.
分 类 号:X53[环境科学与工程—环境工程] X826
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