黄河上游水体中重金属分布特征及重金属污染指数研究

摘要

In order to understand the spatial distribution and evaluate the pollution degree of heavy metals (As, Cd,Cr,Co,Cu,Mn,Ni,Pb,and Zn)in upper reaches of the Yellow River,surface water samples were col-lected from 12 selected sites during two field surveys in April 2014 (drought season)and October 2014 (nor-mal season).The concentrations of heavy metals were determined using inductively coupled plasma mass spec-trometry (ICP-MS)for spatial variation and heavy metal pollution index.The average concentrations of the metals in the drought season and normal season decreased respectively in the order:Cr (18.56μg·L-1 )>As (2.95μg·L-1 )>Ni (1.87μg·L-1 )>Mn (1.20μg·L-1 )>Cu (1.12μg·L-1 )>Zn (0.59μg·L-1 )>Pb (0.08μg·L-1 )>Cd (0.01μg·L-1 );Mn (596.89μg·L-1 )>Zn (52.46μg·L-1 )>Cu (36.27μg· L-1 )>Ni (25.11μg·L-1 )>Cr (23.19μg·L-1 )>Pb (19.51μg·L-1 )>As (7.30μg·L-1 )>Cd (0.37μg·L-1 ).The results were compared with national and international water quality guidelines,as well as liter-ature values reported for the same river in flood season.To assess the composite influence of all the considered metals on the overall quality of the water,heavy metal pollution indices were calculated.The Heavy Metal Pollution Index (HPI)of the river calculated for the individual locations showed ranging from 6.46 to 11.95 in drought season,4.53 to 210.53 in normal season,respectively.Both the distribution of metals and HPI of two seasons revealed obvious seasonal variation.The results showed that the degree of heavy metal contaminant was not very high and had seasonal variation;both the concentrations of metals and HPIs indicated the pollu-tion level of the normal season was higher than it of the drought season.The results of this paper provided reli-able experimental data and theoretical basis for the relevant departments to make further policy decision.%为了研究黄河上游地区水体中重金属含量分布特征及评价该区域重金属污染水平,分别于2014年4月(枯水期)和10月(平水期),在12个采样点采集了24个黄河表层水样。由电感耦合等离子质谱仪 ICP-MS测量水样中 As,Cd,Cr,Co,Cu,Mn,Ni,Pb和Zn的含量,并确定黄河上游水体中重金属分布特征和重金属污染指数。结果显示枯水期重金属的平均浓度顺序是：Cr(18.56μg·L-1)>As(2.95μg·L-1)>Ni (1.87μg·L-1)>Mn(1.20μg·L-1)>Cu(1.12μg·L-1)>Zn(0.59μg·L-1)>Pb(0.08μg·L-1)>Cd (0.01μg·L-1),平水期的重金属平均浓度顺序是：Mn(596.89μg·L-1)>Zn(52.46μg·L-1)>Cu (36.27μg·L-1)>Ni(25.11μg·L-1)>Cr(23.19μg·L-1)>Pb(19.51μg·L-1)>As(7.30μg·L-1)>Cd(0.37μg·L-1)。将重金属含量测定结果与中国和国际水质参考值以及同地区丰水期重金属含量数据进行了比较,结果显示Cr,Mn,Pb和Cu含量高于标准值。同时,用重金属污染指数(HPI)评估所有金属对整个水体的影响,结果表明各选点枯水期 HPI值为6.46~11.95,平水期 HPI 为4.53~210.53。两个季节的重金属分布特征和 HPI都显示了明显的季节性变化。研究结果表明黄河研究流域水体重金属含量及 HPI均显示平水期重金属污染程度较枯水期高,可能与季节性生产及降水变化有关。研究结果可为相关部门制定环保政策提供可信的实验数据和理论依据。