Mine Site Restoration: The Phytoremediation of Arsenic-Contaminated Soils

Abstract

Arsenic (As) is considered one of the most toxic chemicals to both human and environmental health. Mining activities represent one of the main anthropogenic sources of As; the concentration of As in mine soil can reach 9300 mg kg−1. To overcome the major issue of soil As pollution, soil restoration is required. Biological restoration approaches are generally more cost-effective and environmentally sustainable than physical and chemical methods. In particular, phytoremediation, an environmentally friendly technique based on the use of plants to uptake contaminants from soil, has been successfully implemented to restore As-contaminated soils at mine sites. However, mine soils are generally depleted in essential plant nutrients, such as nitrogen (N). Recent research suggests that phytoremediation can be combined with other techniques (physical, chemical, and biological) to enhance the N content and plant biomass. The aim of this review is to assess the current state of knowledge in the field of the restoration of arsenic-impacted mine site soils, focusing on phytoremediation. We critically assess recent work examining the potential of the co-application of amendments with phytoremediation and identify promising technologies and key research gaps. More studies are required to test the effectiveness of using various soil additives to enhance the phytoremediation of As, not only in pot-scale experiments but also in the field, to enable an improved management strategy for mine site restoration in the future.