摘要
沉积物是河流的重要组成部分,而沉积物中重金属的富集严重威胁着水环境安全.黄河流域沿程分布着众多工业城市,且流域水土流失量大,泥沙携带重金属进入河流导致沉积物重金属污染问题日趋严重,研究黄河流域沉积物中重金属污染状况对流域生态安全具有重要意义.收集2000~2020年发表的关于黄河流域沉积物中重金属(铅、镉、铬、砷、锌、铜、镍和汞)含量的数据,首先基于描述性统计及地统计法分析重金属的空间分布特征,进一步采用蒙特卡洛法进行地累积指数(I_(geo))、潜在生态风险及毒性单位概率的评价,最后结合正定矩阵因子分解模型(PMF)与Pearson相关性分析确定污染源个数及贡献率.结果发现,黄河流域沉积物中ω(Pb)、ω(As)、ω(Zn)、ω(Ni)、ω(Cu)、ω(Hg)、ω(Cr)和ω(Cd)的均值分别为26.92、 11.78、 87.17、 31.13、 24.96、 0.07、 73.36和0.58 mg·kg^(-1),分别超过黄河流域各省土壤背景值均值1.27、 1.08、 1.26、 1.05、 1.09、 2.32、 1.14和5.95倍,其中Cd超标倍数最大,应当引起重视;I_(geo):Cd>Hg>Cr>Cu>Pb>Zn>As>Ni,Cd和Hg存在中度-严重污染;数据表明黄河流域上、中和下游沉积物重度生态风险占比分别为18.6%、 15.7%和7.1%,呈递减趋势;黄河流域沉积物中重金属处于低毒性状态;溯源分析表明黄河流域沉积物重金属的4个来源分别是矿业源(42.2%)、自然活动(38.3%)、农业活动(11.6%)和电镀废水(7.9%).研究结果可为黄河流域制定相关污染防控措施提供依据.
As sediment is an essential component of rivers,the enrichment of heavy metals in sediment presents a serious threat to the aquatic environment.Many industrial cities are located along the Yellow River,and heavy metal pollution is a prominent problem in these areas.Thus,the study of heavy metal pollution in sediments of the Yellow River basin is of vital significance to the safety of the Yellow River basin ecosystem.In this study,we collected data on the concentrations of heavy metals(Pb,Cd,Cr,As,Zn,Cu,Ni,and Hg) in the sediments of the Yellow River basin from 2000 to 2020.We first analyzed the spatial distribution characteristics of heavy metals based on descriptive statistics and geostatistics and then used the Monte Carlo method to evaluate the probability of the ground accumulation index(I_(geo)),potential ecological risk,and toxicity units.Finally,the number of pollution sources and their contribution rates were determined by combining the positive definite matrix factor(PMF) decomposition model and Pearson correlation analysis.It was found that the mean values of ω(Pb),ω(As),ω(Zn),ω(Ni),ω(Cu),ω(Hg),ω(Cr),and ω(Cd) in the Yellow River basin sediments were 26.92,11.78,87.17,31.13,24.96,0.07,73.36,and 0.58 mg·kg^(-1),which exceeded the mean soil background values in the Yellow River basin provinces by 1.27,1.08,1.26,1.05,1.09,2.32,1.14,and 5.95 times,respectively,among which Cd exceeded the standard by the largest factor and should be taken seriously.The I_(geo) was ranked as Cd>Hg>Cr>Cu>Pb>Zn>As>Ni,and Cd and Hg showed medium-severe pollution.The proportions of heavy ecological risk in sediments in the upper,middle,and lower reaches of the Yellow River basin were 18.6%,15.7%,and 7.1%,respectively,with a decreasing trend.Heavy metals in the sediments of the Yellow River basin were in a low-toxicity state.The PMF-Pearson correlation analysis showed that the four sources of heavy metals in the Yellow River basin sediments were mining sources(42.2%),natural activities(38.3%),agricultural activities(11.6%),and electroplating wastewater(7.9%).The results of this study can provide a basis for developing relevant pollution prevention and control measures in the Yellow River basin.
作者
庞阔
李敏
刘璐
杨珺斓
赵洪军
PANG Kuo;LI Min;LIU Lu;YANG Jun-lan;ZHAO Hong-jun(College of Environmental Science and Engineering,Beijing Forestry University,Beijing 100083,China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2022年第8期4008-4017,共10页
Environmental Science
基金
国家自然科学基金项目(52070016)。
关键词
沉积物重金属
空间分布
风险评价
蒙特卡洛
PMF模型
黄河
sediment heavy metals
spatial distribution
risk evaluation
Monte Carlo
PMF model
Yellow River
