关键词: 苏北地区, 土壤-水稻系统, 重金属, 暴露风险, 土壤环境质量, 食物安全, 黄潮土, 砂礓黑土

Abstract: Soil environmental quality and its impact on safety of agro-products has been one of the research targets concerning regional environmental quality and sustainable development in the last decade.Based on a geologic survey and grid sampling of North Jiangsu including six counties and cities,Fengxian,Peixian,Tongshan,Suining,Chuzhou and Donghai,a total of 98 pairs of soil and rice grain samples were taken randomly in areas of two major soil types,Huangchaotu(Motudic Entisols) and Shajiang black soil(Vertisols) for analysis of contents of total Cu,Zn,Pb,Cd,Cr,Ni,As and Hg with an atomic adsorption spectrophotometer and an atomic fluorescence spectrophotometer,separately.Pollution levels of the soil and rice samples were assessed against the standards for green food production bases and hazard-free food production bases, and the background values of the region of the 1980s,and heavy metal exposure risk assessment of the rice produced in the region was conducted with R_fD values recommended by USEPA and/or WHO as benchmark.Results show that the environmental quality of the soils from the studied region basically meets the requirements set for green food production base in terms of heavy metal pollution,and on the whole falls into the category of "No Significant Pollution".Nevertheless,R_fD values calculated based on USEPA indicate that rice grown in all the soils of the region does pose some significant As and Cr exposure risk to food safety and rice from some areas does Cd exposure risk.Fortunately,it still falls into the category of "Safe" due to low Cd/Zn ratio.In order to further guard food safety,it is essential to amend and modify criteria for soil environmental quality,take positive measures to control soil pollution,and endeavor to improve the quality of the atmospheric environment.

Key words: North Jiangsu, system of soil-rice, heavy metal, exposure risk, soil environmental quality, food safety, Huangchaotu, Shajiang black soil