Distribution Of Antimony In Paddy Field Soils In Eastern Hunan And Its Influencing Factors

Antimony(Sb)is a toxic and harmful heavy metal.Its distribution in the soil and environmental chemical behavior restrict the safe production of agricultural products source and its influencing factors are related to the prevention and control of soil pollution.In this research,the best agricultural development area-"East Hunan Province"(hereinafter referred to as "Xiangdong Region")was used as the study area,with collecting 34 representative paddy soil profiles which had a total of 198 soil samples.Based on the analysis of the basic physical and chemical properties of the soil,the total content of Sb and the content of available Sb,the research discussed the distribution characteristics and pollution status of soil Sb in the surface of the paddy field in eastern Hunan,and analyzed the external and internal factors affecting the distribution.The main conclusions were as follows:(1)The total content of Sb in the surface soil(plow layer(Ap1)and plow bottom layer(Ap2))(0~30cm)of paddy field in Xiangdong area was 0.046~11.822 mg/kg and the average value of that was 3.320 mg/kg,meanwhile the samples that exceeded the background value of Hunan Province(2.98 mg/kg)were account of 35%;There was no significant difference in the total Sb content of Ap1 and Ap2;Correlation fitting showed that total iron was an important factor affecting the distribution oftotal antimony in the surface soil.Kriging spatial interpolation showed that the Sb distribution in the study area had obvious regional distribution characteristics that content of Sb was high in the north and south and low in the east and west.It may be affected by human-induced activities such as exogenous river input and metal smelting activities.(2)The content of available Sb in the surface soil of paddy field in eastern Hunan was low,all less than 0.074mg/kg;The relative effectiveness coefficient(effective state content accounts for the percentage of total RA)is basically less than 15%,indicating low availability of Sb.Correlation fitting showed that total Sb was the main factor affecting the available Sb content in the top soil,followed by total iron,organic matter,and CEC.(3)The Sb content in the paddy soil with different parent materials decreased as the increase of the soil depth and there was an obvious surface aggregation phenomenon,reflecting the effects of human activities.Second,the background of the Sb content in the paddy soils with different parent materials was different.The background value of Sb in the soil developed by shale weathering and river and lake sediments was about 2.00 mg/kg,and the background value of Sb in the soil developed by the parent material of quaternary red clay,granite weathering and purple sand shale weathering was respectively 1.00mg/kg,0.00 mg/kg,1.00 mg/kg.The characteristics of vertical changes ofSb in paddy soils with different parent materials are different.The contents of Sb in slabs,shale weathering materials,quaternary red clay,and river and lake sediments were concentrated at 0~9.00 mg/kg,0~3.00mg/kg,0~3.00mg/kg,the Sb content in the soil developed by granite weathering and purple sand shale weathering was concentrated at 0~2.00mg/kg;except for the surface layer,the soil layer of each section basically does not exceed Hunan Save background value.The distribution of Sb in the soil layers of various sections was affected by many factors such as the basis Sb content of parent material,the development type of paddy soil,soil minerals,texture,water and other soil characteristics,and external input.