摘要
以江门天沙河流域为研究对象,研究该河流流域表层沉积物中重金属污染情况,分别在天沙河干流的两个出江口、九个主要支流汇流处与工农业聚集区等11个水流断面处进行了合理布置采样点,共采集获得河流底泥表层沉积物与河岸土共28个样品,干燥过筛预处理后,分别采用四酸消解法与改良灰化消解法对样品进行消解处理,并采用电感耦合等离子光谱仪(ICP-MS)测定各样品中Ni、Pb、Zn、Cu、Cd和Cr等6种重金属的总量。对比研究此两种消解提取方法对于样品中重金属元素的提取情况,进一步采用地积累指数评价法对研究区域的重金属污染程度进行风险评估。研究结果显示,此两种消解处理方法对于沉积物样品中6种重金属元素的提取相关性均较好,均呈现显著正相关。对于Cd、Cr、Ni、Cu的数值拟合回归系数r^2均大于0.95,成倍数关系,为1.1—1.6倍;Zn元素的回归系数r2=0.927;Pb元素的回归系数r2=0.932,四酸消解法获得的Pb元素含量较高,约为改良消解灰化法的3.4倍。地累积指数(Muller)分析显示,天沙河表层沉积物的Cd污染达到6级,为极强污染,Cu污染级别为4级,为强污染级;Ni和Zn污染级别为3级,为中等-强污染;Pb和Cr污染级别为2,为中等污染;Cd元素潜在生态危害最大,其余金属元素污染指数为Cu>Ni>Zn>Pb>Cr。
The Tiansha river basin was selected as the research subject of this work.The contamination with heavy metals in the surface sediments of the river basin was studied,being the sampling arranged at 11 flow sections along the river,in the two main confluence estuaries and nine main tributaries,which are the agricultural and industrial accumulation areas of the Tiansha river fields.The sediments and soil samples were dried and digested with the four-acid system and the modified incineration.The total content metal of Ni,Pb,Zn,Cu,Cr and Cd was analyzed by using inductively-coupled plasma mass spectrometry(ICP-MS)and assessed by the geoaccumulation index method.The results showed that the correlation between the two methods for the extraction of six heavy metals was positive.For Cd,Cr,Ni,and Cu,numerical fitting regression coefficient r2 was higher than 0.95 and the number of multiple relations between 1.1 to 1.6 times.In the case of Zn the regression coefficient was r2=0.927 and in the case of Pb r2=0.932.The regression coefficient of Pb by the four-acid digestion method was about 3.4 times higher compared with the value obtained with the modified incineration method.In addition,according to the geo-accumulated index analysis of Muller,the Cd pollution index of the surface sediments of Tiansha river reached level 6,and the Cu pollution index was 4,being considered a high level of pollution.The pollution index of Zn and Ni was 3,being considered a medium-to-high level of pollution.Cr and Pb pollution indexes were 2,considered as moderate pollution.In summary,it can be concluded that Cd element is the worst pollutant among the 6 heavy metals analyzed and it entails a great ecological hazard in the Tiansha river,followed by Cu,and Ni,Zn,Pd,Cr.
作者
李秋华
汪群慧
陈景文
LI Qiuhua;WANG Qunhui;CHEN Jingwen(School of Energy and Environmental Engineering,University of Science and Technology Beijing,Beijing 100083,China;School of Biotechnology and Health Sciences,Wuyi University,Jiangmen 529020,China)
出处
《生态环境学报》
CSCD
北大核心
2020年第12期2423-2432,共10页
Ecology and Environmental Sciences
基金
国家重点研发计划(2018YFC19001003)
江门市基础与理论研究科技计划项目(2016030100270007378,2017030100620016213)
广东省自然科学基金项目(2017A030313319)
广东省教育厅创新强校项目(2015KTSCX142)。
关键词
天沙河
表层沉积物
重金属
消解体系
污染评估
Tiansha River
surficial sediment
heavy metals
ICP-MS digestion methods
pollution assessment
