Spatial Distribution Pattern and Pollution Evaluation of Heavy Metals in Farmland Soil in Guangxi

Abstract

Farmland soil is an indispensable natural resource in agricultural production. A macro analysis of the spatial distribution and pollution level of heavy metals can provide a scientific basis for future farmland pollution control. Based on the measured data of heavy metals in farmland soil in Guangxi since 2014, the spatial distribution characteristics of 6 heavy metals in farmland soil, namely Pb, As, Cd, Cr, Zn and Cu, were discussed, and the pollution status was evaluated using the geo accumulation index method. The results showed that the average values of Pb, As, Cd, Cr, Zn, Cu in farmland soil were higher than the background values of farmland soil in Guangxi. The average contents of Pb, As, Cd, Zn in farmland soil exceeded the soil environmental quality standard (GB15618-2018), and Cr and Cu did not exceed the standard; The spatial distribution characteristics of heavy metals in farmland soils in Guangxi are obviously different. Generally, the content of heavy metals in the middle and north regions is higher than that in the south regions; The land accumulation index is in the order of Zn>Pb>Cd>As>Cu>Cr, in which the average <i>I_geo</i> values of As, Cu and Cr in farmland soil are all less than 0, while affected by local mining activities, the average <i>I_geo</i> values of Zn, Pb and Cd in soil are higher.