Spatial distribution and source apportionment of heavy metals in soil from a typical county-level city of Guangdong Province, China.

The contents of ten heavy metals (Cr, Hg, As, Pb, Ni, Cd, Ti, Cu, Zn and V) in 413 topsoil samples from Puning City, Guangdong Province, China were investigated. Obvious enrichment of Hg, As, Pb, Cd and Zn were presented, and the contents of Hg and As in 5.8% and 3.4% samples respectively were higher than the guideline values recommended by the Chinese Environmental Quality Standard for Soils. Chromium and V were presented no enrichment and no pollution. According to one-way analysis of variance, the mean contents of Hg, Pb, Cu and Zn in land for construction were significantly higher than farmland and natural vegetation, but the land use had no obvious effect on other heavy metals. Furthermore, the potential sources of ten heavy metals were identified and apportioned in combination with geostatistics, correlation analysis and positive matrix factorization model. The results were following as: a) Pb, Zn and Cu mainly origin from vehicle emission and atmosphere deposition, and the hotspots approximately distributed in the areas of intensive traffic and near main roads; b) Hg and Cd were derived to industrial activities related to pharmaceutical industries, the textile and dyeing industries and e-waste recycling industries, and high-value areas were mainly concentrated in the northeast of the urban area where the industrial parks have been distributed; c) Soil parent material (Jurassic shale) was the main source of Cr, Ni, V and Ti; d) As mainly came from agricultural inputs such as pesticides or herbicides, livestock and fertilizers. Meanwhile, the contributions of four sources were 33.08%, 24.04%, 27.11% and 15.77% of the total contribution, respectively.