Distribution Characteristics And Assessment Of Heavy Metals In Soil Of Uncontaminated Agricultural Products Of Guangyuan City

With the development of economy, soil is polluted by industrial" Three wastes" and the heavily using of dustfertilizer pesticide.Soil heavy meatl pollution has become one of the most important environmental problems in the world. So people are anxious for the quality of agricultural products. Guangyuan is the key agricultural products base of Sichuan province. The thesis based on the background and collected 145 soil samples from 7 county of Guanyuan agricultural products base and evaluated by the indexes of single contaminants and combined pollution according to the national standard for evaluation of soil environmental quality, then divide the soil into different levels, Finally analyzed the correlation of the heavy meatls in the soil. In order to make agricultural products developed in a scaled, high quality and industrialized direction, as well as providing a foundation for the construction of national uncontaminated agricultural products.Following conclusions are achieved:According to the indexes of single contaminants pollution the result showed:heavy metals indexes in the soil of Cangxi, Jiange, Yuanba, Shizhong county are less than 1.0 indicating that they meet the requirements of soil environment for producing unconaminated food,but Cd,As form Qingchuan and Wangcang county are more than 1.0 as well as Cd,Cr,Cu from Chaotian district.According to the indexes of combined contaminants pollution the result showed: Only 3 heavy metals indexes of the 145 soil samples are more than 1.0 ,belonging to slight pollution. The others are less than 1.0 indicating that the level of the soil belong to cleanness, so they meet the requirements of soil environment for producing uncontaminated food.According to Cluster Analysis the result showed: The representative element in soil of Jiange, Wangcang, Cangxi, Shizhong county is Cd, Pb, Hg and As respectively. The heavy metals in soil of Qingchuan, Chaotian, Yuanba district have no representative element. The heavy metal Cr and Cu,Cd and Hg of Chaotian district, Pb and Hg of Shizhong Jiange district have obvious correlation. The heavy metals of Cangxi, Wangcang, Qingchuan county and Yuanba district have unobvious correlation. As a result, the soil of agricultural products base in Guangyuan city is in good condition and it is fit for producing uncontaminated food.