Potentially hazardous metals contamination in soil-rice system and it's spatial variation in Shengzhou City, China

There is an increasing concern for potentially hazardous metals pollution, which can threaten crops production and human health. A total of 94 pairs of soil and rice samples were collected from Shengzhou City, southern China. The results showed that the mean concentrations of Cd, Cu, Ni, Pb, Zn in soils were 0.20, 28.64, 27.03, 38.51 and 98.74 mg kg− 1, respectively. Compared with the guideline values, the potentially hazardous metals were enriched to different degrees in paddy soils of the study areas and some were contaminated with these metals. However, the potentially hazardous metals in rice remained at a safe level. The total concentrations of Cd, Cu, Ni, Pb, Zn in soils had moderate variability coefficients of 45%, 47%, 82%, 18%, 32%, respectively. Kriging interpolation procedure and the Local Moran's I index detected the locations of pollution hotspots of these five potentially hazardous metals. The concentrations of Cd, Cu, Ni, Zn in soils had a very similar spatial pattern, with contamination hotspots located together in the middle part of the study area, which is probably due to industrialization and other anthropogenic activities. The accumulation and availability of potentially hazardous metals in soil and rice is influenced by both metal concentrations in soil, and soil-plant physico-chemical properties that influence their uptake by rice. Therefore, we conclude that necessary environmental measures should be taken to control soil pollution in order to limit possible potentially hazardous metals contamination of the food chain in Shengzhou City.