Heavy metals removal from soil by the plants - review

Abstract

Soils may become contaminated by accumulation of heavy metals. Those metals constitute an ill-defined group of inorganic chemical hazards, and those most commonly found at contaminated sites are Lead (Pb), chromium (Cr), arsenic (As), zinc (Zn), cadmium (Cd), copper (Cu), mercury (Hg), and nickel (Ni). The presence of toxic metals in soil can severely inhibit the biodegradation of organic contaminants. to enumerate the heavy metals in soil, to find out the plants which were used to Phytoremediation.  Technologies for remediation of heavy metal-contaminated soils.1) Isolation 2) Immobilization 3) Toxicity and/or mobility reduction: phytoremediation (phytoextraction, phytostabilization, and rhizofiltration) 4) Physical separation 5) Extraction. In this research only considered Phytoremediation. It is called green remediation, botanoremediation, agroremediation, or vegetative remediation, can be defined as an in-situ remediation strategy that uses vegetation and associated microbiota, soil amendments, and agronomic techniques to remove, contain, or render environmental contaminants harmless. The methods used to phytoremediate metal contaminants are slightly different from those used to remediate sites polluted with organic contaminants. according to this study following plants were identified as working Phytoremediation: Brassica juncea L.- Cd, Cu, Zn, Pb. Brassica napus L.- Cd, Cu, Zn, Pb. Cajanus Cajan (L.) Milsp.- As, Cd. Cicer aeritinum L.- Cd, Pb, Cr, Cu. Jatropha curcas L.- Fe, Al, Cu, Mn, Cr, As, Zn, Hg. Lantana camara L.- Pb. etc. heavy metals & metalloids through emissions from the rapidly expanding industrial areas, mine tailings, disposal of high metal wastes, leaded gasoline and paints, land application of fertilizers, animal manures, sewage sludge, pesticides, wastewater irrigation, coal combustion residues, spillage of petrochemicals, and atmospheric deposition. The methods used to phytoremediate metal contaminants are slightly different from those used to remediate sites polluted with organic contaminants. Therefore, above identified plants used to purify the soil by rolling of cultivation and changing the crop pattern and organic manure application of farming field is strongly recommended in this research.