Phytoremediation of arsenic-contaminated soils using arsenic hyperaccumulating ferns

Abstract

Arsenic contamination of soils is a global environmental, agricultural, and health issue given to the toxic and carcinogenic nature of As. Several anthropogenic activities, such as mining and smelting, coal combustion, wood preservation, leather tanning operations, and use of As-based pesticides in agriculture, have led to elevated concentrations of As in soil. Therefore, remediation and restoration of As-contaminated soils is imperative for providing safe food and healthy soils. In contrast to conventional (physicochemical) remediation methods, phytoremediation of As-contaminated soils using As-hyperaccumulating fern species has emerged as an eco-friendly, cost-effective, and efficient technology. Since the discovery of As-hyperaccumulator, Pteris vittata L., several other As-hyperaccumulating fern species have been identified in Pteris and Pityrogramma genera which demonstrated the ability to remove As from soil. This review will briefly discuss about the As dynamics and availability in soil; elucidate the mechanisms involved in As tolerance and (hyper)accumulation by ferns/plants for improving the phytoremediation efficiency; evaluate the capacity of As-hyperaccumulating fern species (e.g., P. vittata, Pityrogramma calomelanos) for phytoremediation of As-contaminated soils under pot and field conditions; and discuss how phosphate amendments, microbes, and agronomic practices can increase phytoremediation efficiency of the ferns.