Heavy Metal Pollution of Soils and Vegetables from Midstream and Downstream of Xiangjiang River

A total of 219 of agricultural soil and 48 of vegetable samples were collected from the midstream and downstream, Hengyang to Changsha, of Xiangjiang River of Hunan Province. The spatial distribution, accumulation characteristics and potential risk of heavy metals in the agricultural soils and vegetables were depicted in details by three different approaches, including total contents of 7 metal elements in soils and vegetables, GIS map of heavy metals in soils, and multi-analysis of the relationship between metals content of soils and egetables in this study. The results show that there are higher accumulations of heavy metals such as As, Cd, Cu, Ni, Pb and Zn in agricultural soils, and the contents of Cd (2.44 mg kg-1), Pb (65.00 mg kg-1) and Zn (144.13 mg kg-1) are 7.97, 3.69 and 1.63 times of background contents of the corresponding heavy metals in soils of Hunan Province, respectively. There are about 13.2% of As, 68.5% of Cd, 2.7% of Cu, 2.7% of Ni, 8.7% of Pb and 15.1% of Zn in all the collected soil samples from the investigated sites which have overran the contents for heavy metal of China Environmental Quality Standard for Soils (GB15618-1995, Grade II). The pollution characteristics of multi-metals in soils are mainly reflected by Cd. Contents of As, Cd, Cu, Pb and Zn in vegetable soils are significantly higher than those in paddy soils, respectively. The ratios of vegetable samples which As, Cd, Ni and Pb concentrations are higher than the Maximum Levels of Contaminants in Foods (GB2762-2005) are 95.8%, 68.8%, 10.4% and 95.8%, respectively. There are significantly positive correlations between the concentrations of Cd, Pb and Zn in vegetables and the content of them in vegetable soils (P 0.01). It is very necessary to focus on potential risk of heavy metals for food safety and human's health in agricultural soils and vegetables in the midstream and downstream of Xiangjiang River, Hunan Province of China.