Overview and Prospects of Selenium Phytoremediation Approaches

Phytoremediation, a plant based technology, is perceived as a novel, low-cost, eco-friendly technology for in-situ management of Se-contaminated soil and water resources. Among the different phytoremediation mechanisms, phytoextraction, phytovolatilization, and rhizofiltration are primarily responsible for the management of Se in a contaminated environment. Selection of the best-suited plant and cultivation strategies are crucial for the success of phytoremediation technology at any given site. For example, Brassica-based cropping systems are about two times more efficient than agroforestry-based systems in removing Se from the contaminated sites. In addition, the potential of several transgenic approaches have been highlighted for further increasing Se accumulation, volatilization, and tolerance by plant species selected for phytoremediation. The accumulation of Se in plant tissues may also act as a deterrent for a number of herbivores like crickets, grasshoppers, prairie dogs, etc., while the entry of Se into the food chain can be minimized by growing non-food plants, e.g. flowers, in Se-contaminated soils. In this chapter, a number of alternatives for safe disposal and utilization of Se-rich biomass have also been discussed. These options will greatly help in promoting the adoption of phytoremediation as a vital tool in sustainable management of Se-contaminated soil and water resources.