Source Analysis of Soil Heavy Metals in Agricultural Land in Mountainous Areas Based on PMF Model

In order to understand pollution of soil heavy metals in agricultural land in mountainous areas and identify pollution sources of eight kinds of heavy metals, 1311 samples of soil surface（0-20 cm）were collected in the study area, and pH, As, Cd, Cr, Cu, Hg, Ni, Pb, Zn were tested and analyzed．Nemerow comprehensive index method, geostatistics method, correlation analysis, one-way analysis of variance and positive definite matrix（PMF）model were used to study characteristics and possible pollution sources of heavy metal pollution in agricultural land in mountainous areas．Results showed that contents of eight heavy metals in the soil of study area were significantly higher than background value of soil in Chongqing．Except for heavy pollution in some areas, soil in the study area was generally clean or slightly polluted, and main polluting element was Cd．PMF model results showed that there were three main sources of soil heavy metal pollution in the study area, namely natural parent material source（Cd, Cr, Cu, Ni, Pb, Zn）, mining activity source（As, Cr, Hg, Pb, Zn ）, source of agricultural activities（As, Cd , Cr, Hg ）．