Evaluation on soil heavy metals and organochlorine pesticides pollution in main grain producing area based on ArcGIS—A case study of Liaocheng

With the rapid economic development, the soil environment has been polluted in varying degrees. The quality of the soil in the major grain producing areas affects the food safety and human health. Liaocheng City, the major grain producing areas in Shandong Province, covers an arable land of 70.01 × 10⁴hm². In order to investigate the heavy metals and organochlorine pesticides pollution institution, the farmland of Liaocheng had been divided into 136 units. One sampling point had been selected in each unit. Firstly, the location of sampling points had been ensured by GPS, and the surface soil of 136 sampling points had been collected. 10 kinds of pollutants had been monitored, which included As, Cd, Cr, Cu, Hg, Ni, Pb, Zn, DDTs and BHCs. Secondly, the single factor index had been used to evaluate the degree of soil pollution. The results showed that the polluted degrees of all heavy metals and organochlorine pesticides were different. The order of heavy metals pollution was Hg>;Cu>;Cd>;Zn>;Pb>;As>;Ni. The order of organochlorine pesticides pollution was DDTs>; BHCs. Thirdly, all different pollutants indexes had been inputted to ArcGIS. Based on the spatial analyst module in ArcGIS, Ordinary Kriging method had been used to finish the spatial interpolation of every kind of pollutants. At last, the spatial distribution maps of every kind of pollutants had been finished based on ArcGIS. The results showed that the pollution of the heavy metals and the organchlorine pesticides was not so heavily and had little influence upon the food production. By contrast, the soil pollution around the towns was more serious than that far from the towns. The most serious polluted area of the organchlorine pesticides located at Linqing county. Therefore, the areas surrounding all towns and the whole areas of Linqing county should be mainly protected.