关键词: 农田土壤, 重金属污染, 农产品安全, 风险管控, 防治对策

Abstract: Soil is the foundation for sustainable agricultural development. After nearly 40 years of rapid economic expansion and intensive agricultural production, the problems of soil pollution and soil environmental quality deterioration in Chinas farmlands have gradually come into focus. At present, the heavy metal pollution in farmlands has become increasingly serious and poses a potential threat to agricultural product safety. In this paper, we first summarized the current status and characteristics of heavy metal pollution in farmland soils, and sources of heavy metal pollution in farmlands and research advances in soil remediation in China. It showed that (1) in general, the rate of heavy metal contamination exceeding safety standards in farmland soils is relatively high, but contamination is mostly light; (2) among the heavy metals, Cd, As, Hg, Pb and Cr are the five major health risk elements in contaminated farmland soils, especially Cd, while ecologically hazardous elements Ni, Cu and Zn, pose relatively low environmental risk; (3) in general, the characteristics of the pollution distribution indicates pollution is more serious in south than in north and in east than in west; and (4) the pollution trend shows gradual heavy metal transfers from industrial to agricultural sources, from suburbs to rural areas, and from soil contamination to food chain pollution. Next, we did bibliometric analysis of the hotspots and research trend of heavy metal pollution prevention and control of farmland pollution in China during the past 30 years. According to the analysis, researches of pollution prevention and control started around 2000 and entered a rapid development stage after 2009. The research hotspots mainly included heavy metal pollution monitoring, soil environmental quality assessment, heavy metal-contaminated soil remediations etc. And in the last 10 years, remediation technologies have changed from single to multi-technique applications. We then evaluated the general remediation procedures and the techniques for the safe utilization of heavy metal polluted farmland soils at different pollution levels and for the control of high-risk polluted soils. Finally, we discussed the current problems in heavy metal pollution prevention in farmlands in China and prospects for key research fields. We put forward a technical system for farmland heavy metal pollution prevention and control based on combining heavy metal source and environmental risk control measures to provide references for future research planning and technology development for the prevention of heavy metal pollution in China's farmlands.

Key words: farmland, heavy metal pollution, food security, risk control, prevention strategies