Analysis on Spatiotemporal Distribution Features of Heavy Metals in Soil-Rice Agricultural System in Zhangjiagang City, China

Abstract

Abstract-To assess the impact of heavy metal contamination on the soil-rice agricultural ecosystem, the distribution of heavy metals in Zhangjiagang City was analyzed by taking samples from the paddy fields. The result show that contents of Cu, Pb in soil were increased and here are analogous pollution sources due to the similar spatial distribution of Cr and Zn. Concentration of heavy metals vary in different organs of rice, and the bioaccumulation pattern is root > leaf > grain. The enrichment capabilities for different heavy metal elements in same rice organ followed an order of Cu>Pb>Zn>Cr for root, Pb>Zn>Cu>Cr for leaf, and Zn is slightly higher than Cu in grain. The comprehensive pollution index of the soil was lower than 1;The grain of the rice is slightly polluted by Cr in the sampling point of HPC and its single factor indexes of Cu and Zn were both higher than the other sampling sites, while the rice grain is less polluted in other study areas. Therefore, it is necessary to ensure grain quality safety based on the accumulation coefficient characteristics and the spatial distribution of heavy metal pollution. This research offers scientific evidences and data references for local policy makers to rightly maintain the safety and sustainability of agriculture ecosystem in Zhangjiagang City.