摘要
准确评价地块尺度的农田重金属污染状况及识别土壤重金属污染成因对农田土壤生态保护具有重要的实践价值。经长株潭重金属污染耕地修复综合治理试点调查发现,湘潭县部分远离工矿企业的地块存在成因未明的重金属Cd污染,文章选取湘潭县Y镇某Cd污染水田地块为研究对象,通过测定土壤中重金属含量,基于内梅罗污染指数法和UNMIX模型,评估土壤重金属污染状况,识别其污染成因。结果表明:(1)研究区生态环境整体处于中等风险状况,水田土壤中元素Ni、Cr、Pb、Zn、Cd、Hg、As的含量均值分别达到了湖南省土壤环境背景值的149%、158%、246%、144%、554%、274%、135%,以农用地土壤污染风险筛选值作为标准,Cd的点位超标率达到了45.83%,综合污染指数达到了2.27,污染较为严重;(2)UNMIX模型对地块尺度的农田重金属污染源解析问题具有适宜性。Ni、Cu、Cr、Pb、Hg、As含量变化主要受土壤自身理化性质的影响,而土壤中Zn、Cd主要来源于人为活动,无序的农业投入是造成Cd污染异常的主要原因。
It is of great practical value to accurately evaluate the status of heavy metal contamination in farmland and identify the causes of heavy metal pollution in farmland.According to the pilot investigation of the restoration and comprehensive treatment of heavy metal polluted farmland in Changsha-Zhuzhou-Xiangtan Region,it was found that some plots far away from industrial and mining enterprises in Xiangtan County were polluted by heavy metal Cd with unknown causes.Therefore,this paper selected a Cd polluted paddy field plot in Y Town of Xiangtan County as the research object.Through measuring the content of heavy metals in the soil,and based on the Nemerow index method and Unmix model,assess the status of soil heavy metal pollution and identify the cause of contamination.The results showed as follows:(1)The ecological environment in the study area was at medium risk.The average contents of Ni,Cr,Pb,Zn,Cd,Hg and As in paddy soil reached 149%,158%,246%,144%,554%,274%and 135%of the background value of soil environment in Hunan Province,respectively.Taking the screening value of soil pollution risk of agricultural land as the standard,the over-standard rate of Cd point reached 45.83%,and the comprehensive pollution index reached 2.27,indicating serious pollution.(2)UNMIX model is suitable for the analysis of heavy metal pollution sources in farmland at the plot scale.The contents of Ni,Cu,Cr,Pb,Hg and As were more affected by the physical and chemical properties of the soil,while the Zn and Cd in the soil were mainly from human activities,and disorderly agricultural input was the main cause of Cd pollution abnormality.
作者
董曼慧
夏卫生
周浩
朱捍华
DONG Manhui;XIA Weisheng;ZHOU Hao;ZHU Hanhua(College of Geographic science,Hunan Normal University,Changsha 410000,China;Institute of Subtropical Agriculture,Chinese Academy of Sciences,Changsha 410125,China)
出处
《环境科学与技术》
CAS
CSCD
北大核心
2023年第S01期60-66,共7页
Environmental Science & Technology
基金
湖南省自然资源厅项目:湖南省矿产资源有偿使用权益框架构建及权责分配研究(2020-05)
农业部长江中游平原农业环境重点实验室开放基金项目:水稻土旱化种植过程中镉迁移特征研究(531220-1291)
关键词
重金属污染
地块
污染评价
污染成因
UNMIX模型
湘潭县
heavy metal pollution
plot
pollution assessment
pollution causes
UNMIX model
Xiangtan County
