Safe utilization of heavy metal-contaminated farmland: Goals, technical options, and extendable technology

A major task for current soil environmental study is to form problem-solving schemes for the safe utilization of contaminated farmland. Is the scientific community able to provide such schemes as quickly as possible to meet the need by the national "Action Plan for Soil Pollution Prevention and Control"? Here we analyzed the fundamental concepts and decision tree for soil pollution control, based on which the goals, technical options and extendable technology for the safe utilization of contaminated farmland were explored. It is proposed that safe utilization of the contaminated farmland could be referred both in the broad sense and in the narrow sense, with the narrow safe utilization being the priority. The safe utilization of contaminated farmland aims to the production of foods meeting the national food standards, but not the immobilization or cleanup of soil contaminants. Selection and cultivation of low-Cd crops is a promising technology, while the coupled use of metal immobilizers may increase the upper threshold of farmland metal contamination suitable for the safe utilization. We suggest that cost, effect and secondary eco-toxicity are important criteria for evaluating the safe utilization technology, and the form of the extendable technology may consider the traditional agronomic elements like seeds, fertilizers and tillage regime. This work is supposed to promote the translation of soil pollution control knowledge to the safe farming technology, which may ultimately serve the goals of the "Action Plant for Soil Pollution Prevention and Control".