闽西南崩岗土壤重金属含量、分布、来源及生态风险

发布时间：2019-01-19 12:20

【摘要】：选取福建省长汀县黄泥坑崩岗群内2处典型崩岗及附近一无崩岗山坡(对照区),采样并测定了63份0~20 cm土壤样品Cu、Zn、Ni、Pb、Cr、As、Cd含量,运用相关分析与主成分分析进行重金属来源辨识,并应用Hankanson潜在生态风险指数法,以福建省背景值和国家二级标准作为参比,对研究区重金属进行潜在生态风险评价。结果表明:研究区土壤重金属含量从高到低的顺序依次为Zn(105.56 mg·kg~(-1))Pb(67.21 mg·kg~(-1))As(61.47 mg·kg~(-1))Cu(22.33 mg·kg~(-1))Cr(17.12 mg·kg~(-1))Ni(5.24 mg·kg~(-1))Cd(0.80 mg·kg~(-1)),Pb、Cd含量表现为崩岗区对照区,Cu、Zn、Ni、Cr、As、Cd含量与之相反。1号崩岗Zn、Pb、As和Cd平均值分别是福建省背景值的1.12倍、2.82倍、8.68倍和13.33倍,2号崩岗这4种元素平均值分别是背景值的1.11倍、1.36倍、11.22倍和16.67倍,对照区该4种元素平均值分别是背景值的1.58倍、1.60倍、5.14倍和14.44倍;与国家土壤环境质量二级标准比较得出,崩岗区和对照区As平均值分别超标1.92倍和2.70倍,Cd平均值分别超标2.31倍和2.60倍。从集水坡面到沟道末端,崩岗区Pb、Zn、Cd含量呈增加趋势,Cu、Cr含量基本维持稳定,Ni含量有所降低;从坡面上部到下部,对照区Cu、Zn、Ni、Cr、Cd含量呈增加趋势,Pb含量略有降低;As含量在研究区的分布无明显变化。Cu、Ni、Cr主要来源为成土母质,Zn主要来源于禽畜养殖,Cd、As的主要来源包基岩风化稀土开采,Pb主要来源于基岩矿化、煤炭燃烧及汽车尾气排放等复合污染源。以福建省背景值为参比时,Cd潜在生态风险系数达到"极强风险",As为"较强风险",其余均为"轻微风险";以国家二级标准为参比时,Cd属"较强风险",其余均为"轻微风险"。潜在生态风险指数(Ri)表现为2号崩岗对照区1号崩岗。研究区Cd、As污染已较为严重,应采取相应的安全防范措施。
[Abstract]:The contents of Cu,Zn,Ni,Pb,Cr,As,Cd in 63 soil samples of 0 ~ 20 cm were sampled and determined in two typical landslides and a nearby hillside (control area) in Huangyakeng Group, Changting County, Fujian Province. The sources of heavy metals were identified by correlation analysis and principal component analysis. The potential ecological risk of heavy metals in the study area was evaluated by using the Hankanson potential ecological risk index method and using the background value of Fujian Province and the national secondary standard as the reference. The results showed that the order of heavy metal content from high to low was Zn (105.56 mg kg~ (-1) Pb (67.21 mg kg~) (-1) As (61.47 mg kg~ (-1) Cu (22.33 mg). Kg~ (-1) Cr (17.12 mg kg~ (-1) Ni (5.24 mg kg~) (-1) Cd (0.80 mg kg~ (-1),) The content of Pb,Cd was 1.12 times, 2.82 times, 8.68 times and 13.33 times of the background value of Fujian Province, respectively, and the content of Cu,Zn,Ni,Cr,As,Cd was opposite to that of the control area in the collapse area, and the average value of Zn,Pb,As and Cd was 1.12 times, 2.82 times, 8.68 times and 13.33 times of the background value of Fujian Province, respectively. The average values of the four elements were 1.11 times, 1.36 times, 11.22 times and 16.67 times of the background values, respectively. The average values of the four elements in the control area were 1.58 times, 1.60 times, 5.14 times and 14.44 times of the background values, respectively. Compared with the national standard of soil environmental quality, the average value of As was 1.92 times and 2.70 times of that of the control area, and the average value of Cd was 2.31 times and 2.60 times higher than the national standard. From the catchment slope to the end of the channel, the content of Pb,Zn,Cd increased, the content of Cu,Cr remained stable, and the content of Ni decreased. From the top to the bottom of the slope, the content of Cu,Zn,Ni,Cr,Cd increased and the content of Pb decreased slightly in the control area. There was no obvious change in the distribution of As content in the study area. The main sources of Cu,Ni,Cr were soil-forming parent material, the main source of Zn was livestock farming, the main source of Cd,As was weathering rare earth mining of bedrock, the main source of Pb was bedrock mineralization. Coal combustion and automobile exhaust emissions and other composite sources of pollution. When the background value of Fujian Province is taken as reference, the potential ecological risk coefficient of Cd reaches "very strong risk", As is "strong risk", and the rest is "minor risk". Cd is a "strong risk" and the rest are "minor risk" when compared with the national secondary standard. The potential ecological risk index (Ri) was No. 1 in the control area of No. 2 collapse. The Cd,As pollution in the study area has been serious, and corresponding safety precautions should be taken.
【作者单位】：福建师范大学地理科学学院;湿润亚热带山地生态国家重点实验室培育基地;福建师范大学地理研究所;
【基金】：国家自然科学基金项目(41171232,41371512) 国家科技支撑计划项目(2013BAC08B03)资助~~
【分类号】：S157.1

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