Assessing spatial-temporal variation of heavy metals contamination of sediments using GIS 3D spatial analysis methods in Dexing mines, Jiangxi province, China

Dexing mines located in the east of China. They have been exploited for more 20 years and the environment pollution in this area has become very severe. It is very important to assess the spatial-temporal variation of regional environment contamination for monitoring the environment quality variation and contamination trend. 330 Sediment samples in Dexing region were collected and analyzed for As, Hg, Cd, Cr, Zn, Cu and Pb in 2004 and 1989. The maximum of As, Hg, Cd, Cr, Zn, Cu and Pb concentration in 2004 in sediments were up to 9, 4, 4.6, 1.5, 5.9, 6.3 and 5.6 times higher than theirs level in 1989, respectively. Meanwhile, the geoaccumulation index (Igeo) was used to assess the environment quality. In the end, spatial-temporal contrast was performed using GIS 3D spatial analysis from original testing data and geoaccumulation index. The contrast results indicated that there existed slightly contamination of As, Cd, Cu and Pb in 1989, mainly concentrated within little scope along the mid-lower courses of Dexing river and there were different extents of contamination of As, Cd, Zn, Cu and Pb in sediments in 2004, especially in the areas of the Dexing river, Dawu river and middle-lower courses Le´an river, while few contamination occurred in those areas in 1989. All the contrast results indicated that the extent and scope of heavy metals contamination of sediments in 2004 were bigger than that of 1989.