Potential sources and associated risk assessment of potentially toxic elements in paddy soils of a combined urban and rural area

The contamination of combined urban and rural area is a growing environmental issue due to rapid industrialization in China. This study investigated the eight potentially toxic elements (PTEs) arsenic (As), lead (Pb), cadmium (Cd), mercury (Hg), chromium (Cr), copper (Cu), nickel (Ni), and zinc (Zn) in paddy fields in a combined urban and rural area in Shaoxing city, Zhejiang province. Concentrations of the PTEs were determined in 60 topsoil samples (0–20 cm) collected from paddy fields in a combined urban and rural area in Shaoxing city, Zhejiang province, southeast China. The average contents of Pb, Cu, Zn, Cd, Hg, and As in the paddy soils increased by 23.7, 6.9, 17.0, 79.8, 62.5, and 47.9%, respectively, relative to their corresponding natural background concentrations. The mean contents of Cr and Ni did not exceed their background values. Multivariate statistical and geostatistical methods were used to distinguish between the PTEs (Cd, As, Pb, Zn, and Hg) contaminating the soils of the study area from those (Cr, Cu, and Ni) at background concentrations. About 17.2% of the soils were moderately polluted with PTEs as a result of urbanization. The results may be useful to policy makers in agricultural and urban management.