Distribution Characteristics And Assessment Of Heavy Metals In Two Types Of Soil For The Grape Base At The Eastern Foot Of Helan Mountain Of Ningxia

The eastern area of Helan mountain has been recognized as golden place of growing high-quality wine grapes of domestic and overseas,with its unique geography,climate and soil advantages,which make it become one of China's three major geographical origin of grapes.But with the rapid development of industry and agriculture,all kinds of chemical products,agricultural film,pesticides and fertilizer were widely used,which make the grape of eastern area of Helan mountain appear production safety such as the emergence of potential crisis,the problem of soil heavy metal accumulation and potential risk in soil is particularly prominent.In view of heavy metal accumulation has a direct impact on soil environmental quality,soil fertility and productivity.Thus this study selected the main soil types of grape area at the eastern foot of Helan mountain-gravelly light sierozem and common sierozem as the research object,Zinc(Zn),lead(Pb),chromium(Cr),nickel(Ni),copper(Cu),cadmium(Cd),arsenic(As)and mercury(Hg)in two different types of soils,ertilizer and irrigation water were determined.Correlation analysis,principal component analysis and cluster analysis were used to explore the heavy metal factors influencing and the sources in the two soil types.Taking the national soil standards Grade II,Ningxia Regional soil background value,foot of Helan mountain alluvial plains background value as the standard,study on the accumulation of heavy metals in soils and the sources of foreign input.And the use of pollution index method and potential ecological risk index method to evaluate the degree of heavy metal pollution and the degree of harm.The research indicates:(1)The average concentrations of eight heavy metals in two soil types were below the national standards Grade II,but higher than Ningxia Regional soil background values of Cr,Cu and Ni.The element accumulation of Cr,Cu and Ni is significant in gravelly light sierozem;Cr,Cu,Ni and Hg had obvious accumulation tendency in the common calcareous soil.(2)The content of heavy metals in synthetic organic fertilizer were higher than that farm base fertilizer(except Hg and As)of along the Helan Mountain area;The contents of Cu,Ni,Cr and Hg in the base fertilizer were significantly higher than those in synthetic organic fertilizer of Qingtongxia producing area.In the Qingtongxia producing area the irrigation water influences the accumulation of Cr and As in common sierozem soil.(3)Correlation analysis,cluster analysis and principal components found the Ni,Cu,Cr and Zn may have a similar source in gravelly light sierozem soil;Hg,As may derive from soil parent material;Pb may derive from road traffic;Cd may derive from agricultural activities.Zn,Cu,Cr,Hg and As may derive from soil parent material,Cr may derive from organic fertilizer and irrigation water in common sierozem soil;Pb and Zn may come from road traffic;Cd and Ni may derive from agricultural activities.(4)The single-factor pollution index of 8 heavy metals in gravelly light sierozem were sorted by the following:Cu>Ni>Cr>Pb>Hg>As>Zn>Cd,which were mainly polluted by heavy metal Cu,Ni,and Cr;While in common sierozem the single-factor pollution index of 8 heavy metals followed the order:Hg>Cu>Ni>Cr>As>Cd>Pb>Zn,and were mainly polluted by heavy metal Cu,Ni,Cr and Hg.(5)The potential ecological risk of individual coefficients of 8 heavy metals in gravelly light sierozem soil belongs to slight ecological harm degree;The average value of the single factor of 7 kinds of heavy metal elements(except Hg)in the ordinary calcareous soil was a slight ecological harm degree,Hg is in the moderate ecological harm degree.In general,the integrated potential ecological risk of 8 heavy metals was belonged to the slight level on the two soil types.Hg was the main potential ecological risk factor of the two soil types,Cd was a secondary potential ecological factor.