Sources and health risks of heavy metals in soils and vegetables from intensive human intervention areas in South China

Abstract

Heavy metal pollution greatly harms the soil environment and poses threats to food safety and human health. This study aimed to quantify and analyze the sources of heavy metals and assess the health risks associated with the human intake of contaminated vegetables in South China. Heavy metals (Cd, As, Hg, Cu, Ni, Pb, Zn, and Cr) in soil and vegetables (leaf vegetables, legume vegetables, and cucurbits) were investigated and evaluated for contamination. By combining the correlation analysis (CA), positive matrix factorization (PMF), and GeoDetector model, source apportionments were comprehensively identified. Results showed that Cd was the predominant element in soils throughout the study area. Industrial (28.36 %, 20.24 %, 31.50 %), agricultural (27.19 %, 46.50 %, 27.30 %), besides traffic, atmospheric deposition and natural sources were identified as the dominant sources of heavy metals in GD01, GD02, and GD03, respectively. The human health risk assessment showed that the total non-cancer risk of heavy metals (i.e., Cr, Ni, As, Cd, and Pb) ingested through vegetables was 2.3E+00 for children and 9.67E-01 for adults, and the total cancer risk for children was 2.54E-02 and 1.07E-02 for adults, both of which exceeded acceptable levels. It is worth noting that children are more susceptible to health risks due to the consumption of contaminated vegetables than adults.

Keywords: Dietary health risk; GeoDetector model; Heavy metals; Positive matrix factorization; Soil and plants; Source apportionment.