Soil, as the starting point of the food chain, plays a central role in food safety.

However, according to the 2015 State of the World's Soil Resources Report released by the Food and Agriculture Organization of the United Nations, approximately 33% of soils worldwide are in a state of degradation due to excessive or inappropriate human development and utilization.

Soil heavy metal pollution is one of the most common and serious environmental problems worldwide. Heavy metal pollution not only reduces crop yields, but also affects the health of consumers of agricultural products [1-4]. As people increasingly realize the impact of heavy metals in food on human health, the quality of soil resources has attracted widespread attention.