Bioremediation of heavy metal(loid)s in agricultural soils and crops

Heavy metal(loid) contamination in crops threatens the quality and safety of food and fodder. This contamination affects human health, as non-biodegradable heavy metal(loid)s can build up in the body through the food chain and bioaccumulation processes. Although heavy metal(loid)s exist naturally, their displacement and extensive use in chemicals and consumer products heighten the risk of accumulation in agricultural soils and crops. Managing or removing these hazardous materials from agricultural soils is challenging, owing to the large spatial distribution of contaminants, as well as limited technical and management options. However, concerns regarding agricultural soil quality and food safety have led to interest in environmentally friendly methods, such as the bioremediation of agricultural soils contaminated with heavy metal(loid)s. Given the low-to-moderate levels and diffused nature of heavy metal(loid) pollution in agricultural soils, one strategy is to cultivate crops that can tolerate these heavy metal(loid)s. Additionally, scalable bioremediation strategies include the bioengineering of crop varieties that are heavy metal(loid) resistant, and ecosystem-level bioengineering approaches for soil remediation. In this Review, we discuss trans-disciplinary approaches that integrate traditional bioremediation with crop bioengineering, microbiome engineering and nanotechnology to develop effective solutions for heavy metal(loid)-contaminated agricultural soils.