Development of field platforms for bioremediation of heavy metal-contaminated site

Abstract

An irrigation system in areas near urban periphery is partial or totally relies on untreated sewage effluents. There is very less data available about heavy metal status in raw sewage used for soil irrigation in Pakistan. On the other hand, soil of arid areas and semiarid areas is rich in metals like nickel, zinc, copper, and lead. The bioavailability of these heavy metals is affected largely by physical and chemical characteristics of soil and partially affected by characteristics of plants. This issue is a major concern for the health of humans and animals. Therefore, in order to prevent the possible health hazards of metals in agrarian land monitoring of soil, water and plant quality is essential. Heavy metal-contaminated soils need to be remediated. In Pakistan as a developing country, soil reclamation methods include physical and chemical management that cannot be brought into action because of expensive technologies involved. Phytoremediation, in general, phytoextraction, and microbial remediation in particular offer a promising alternative to conventional engineering-based technologies. Phytoremediation is an emerging technology that may be used to clean up contaminated soil in which plants are used for removing pollutants from the contaminated soils. Phytoextraction remediation technique has two strategies such as natural phytoextraction and chemically enhanced phytoextraction. In one study (Rawalpindi, Pakistan), tolerance potential of plants (Zea mays, sorghum, Helianthus, Brassica) was assessed against deleterious effects of heavy metals (Pb, Cd, Cr, Cu) on plant growth, and role of chelator (EDTA, DTPA, and NTA) and tolerant fungal strains was also checked to increase the tolerance index. By 3 years of research, it was assessed that heavy metal uptake and their translocation in biomass of plant enhanced the phytoremediation process from contaminated soil. Phytoremediation research in field can provide capacity building to youth and farmer community. By the bioremediation of soil and water, it is possible to produce biofuel, biomass, and gasification for energy production. Bioremediation techniques will provide training and capacity building to youth and serve an important role at field level for technology transfer and as a broker of emerging technologies.