黄河底泥重金属空间分异影响因子与源解析研究

Influence factors of spatial differentiation and source analysis of heavy metals of sediment in the Yellow River

为深入分析黄河底泥重金属空间分异影响因子及来源途径,以黄河干流宁夏段底泥重金属(Cu、Ni、Zn、Cr、Pb和Cd)为研究对象,基于地理探测器模型探测其风险因子及来源。结果表明:1)底泥重金属除Zn外质量比平均值均超过其土壤值,尤其Cr和Cd达背景值的3.57和1.39倍,受人类影响大,累积明显;2)重金属空间分异解释力最大的因子为路网密度(Q_(D,H)>0.50),其次为人均工业产值(除Cd外,Q_(D,H)>0.50),最小的因子为植被盖度(Q_(D,H)<0.20),因子交互作用均为增强型;3)底泥中Cu和Pb为交通源和上游输送,Ni和Zn为成土母质和大气沉降,Cr为工业源,Cd为交通和农业源。探测的风险区主要为青铜峡市、兴庆区和惠农区。此结论可为黄河流域环境保护和污染治理提供依据。

To further analyze the influencing factors of spatial differentiation and source pathways of heavy metals in the Yellow River sediment,we collected 36 samples in surface sediment(0-5 cm)of the Ningxia section of the Yellow River mainstream and measured concentrations of heavy metals(Cu,Ni,Zn,Cr,Pb,and Cd)using inductively coupled plasma mass spectrometry(ICP-MS).12 influencing factors were designated,including 6 natural factors(pH,TOC,DEM,salinity(EC),vegetation coverage(VC)and soil types(ST))and 6 anthropogenic factors(land use types(LUT),population density(PD),per capita industrial production(PIP),per capita agricultural production(PAP),per capita income(PI)and road network density(RD)).Based on the geographical detector model,this paper analyzed the influence of 12 factors on the spatial differentiation of six heavy metals and detected their risk factors and sources.The results show that:(1)The average values of heavy metals except for Zn in the sediments of the Yellow River are higher than their corresponding background values(especially Cr and Cd were 3.57 and 1.39 times of the background values),which were greatly influenced by human beings and accumulated obviously.(2)Influencing factor of the biggest explanatory power for heavy metal spatial differentiation is RD(Q_(D,H)>0.50),then PIP(excluding Cd,Q_(D,H)>0.50)and the smallest is VC(Q_(D,H)<0.20).(3)Interaction type of factors is ascertained for mostly double factor enhancement type,a few non-linear enhancement types,and no independence and weakness type.Interaction of VC or LUT and other factors were the main non-linear enhancement type.(4)Sources of heavy metals in sediments of the Yellow River were different.Cu and Pb were closely related,and their common pollution sources were traffic and upstream transportation.The correlation between Ni and Zn was strong and they could mainly come from the parent material and atmospheric deposition.Cr derived mainly from industrial discharges and sources of Cd were traffic and the use of fertilizer and pesticide.(5)The detected risk areas were mainly Qingtongxia city,Xingqing district,and Huinong district.The main polluted metals in Qingtongxia city were Cr and Cd,Cd,Pb,and Cu in Xingqing district,and Cr,Cd,Pb,and Cu in Huinong district.