摘要
为探究影响土壤中重金属累积和生物有效性的因素,以桂北地区某铅锌矿流域为研究对象,综合运用单因子指数法、风险评价编码法(RAC)、多元线性回归模型(MLR)和随机森林模型(RF)进行土壤重金属(Pb、Zn、Cu和Cr)累积影响因素分析及生物有效性预测。结果表明:研究区Cr含量无超标且空间分布相对均匀(变异系数为0.51);Cu、Pb和Zn的含量均值(分别为52.58、280.31 mg·kg^(-1)和654.71 mg·kg^(-1))均大于广西西江流域土壤重金属背景值,在思的河山前和地下河入口处全量和生物有效性均较大,对土壤生态环境具有一定风险;对于重金属全量分布和生物有效态的影响因素,阳离子交换量(CEC)、黏粒(Clay)、土壤有机质(SOM)和铁铝氧化物对Cr影响较大,SOM、Clay、pH和铁铝氧化物对Cu影响较大,pH、电导率(EC)和Clay对Pb影响较大,CEC、pH、土壤质地和铁铝氧化物对Zn影响较大;生物有效性预测结果显示RF和MLR均可较好地预测土壤重金属的全量与次生相,其中RF预测的R2区间为0.44~0.93,MLR预测的R2区间为0.30~0.72,RF预测结果表现更为准确。
Taking a typical lead–zinc mining area in northern Guangxi as the research object,the single factor pollution index,risk assessment code(RAC),multiple linear regression(MLR),and random forest(RF)methods were used comprehensively to analyze the influencing factors of accumulation and bioavailability prediction of soil heavy metals(Pb,Zn,Cu,and Cr)quantitatively.The results showed that the Cr content was relatively evenly distributed spatially and did not exceed the background value(the coefficient of variation was 0.51).The average values of the Cu,Pb,and Zn contents exceeded the background values(52.58,280.31 mg·kg^(-1),and 654.71 mg·kg^(-1),respectively),and the total amount and bioavailability were greater in front of the Sidi River mountain and at the entrance of the subterranean river,which presents a certain risk to the soil ecological environment.Among the factors influencing total heavy metal distribution and bioavailability,CEC,clay,SOM,and iron-aluminum oxides had a greater effect on Cr;SOM,clay,pH,and iron-aluminum oxides had a greater effect on Cu;pH,EC,and clay had a greater effect on Pb;and CEC,pH,soil texture,and iron-aluminum oxides had a greater effect on Zn.The bioavailability prediction results showed that both RF and MLR could better predict the total amount and secondary phases of soil heavy metals,with an R2 interval of 0.44–0.93 for RF and 0.30–0.72 for MLR.The RF prediction results were most accurate.
作者
潘泳兴
陈盟
王櫹橦
刘楠
PAN Yongxing;CHEN Meng;WANG Xiaotong;LIU Nan(College of Environmental Science and Engineering,Guilin University of Technology,Guilin 541004,China;Guangxi Collaborative Innovation Center for Water Pollution Control and Water Security in Karst Area,Guilin 541004,China;College of Earth Science,Guilin University of Technology,Guilin 541004,China)
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2024年第4期845-857,共13页
Journal of Agro-Environment Science
基金
广西自然科学基金项目(2020GXNSFBA297050)
广西科技基地和人才专项(桂科AD19110046)。