A Review on Heavy Metal Contamination in Agricultural Soil

Soil contamination is a major environmental issue worldwide. Soil is a complex structure and contains mainly five major components i.e. mineral matter, water, air, organic matter and living organisms. The quantity of these components in the soil does not remain the same but varies with the locality. Therefore, it is essential to make an adequate land management to maintain the quality of agricultural soil. Presence of different kinds of heavy metals such as As, Cd, Cr, Hg, Pb, Co, Ni, Cu, Mn, and Zn etc. Those are important environmental pollutants that cause toxic effects to plants and microorganisms in soil; thus, lessening productivity and posing dangerous threats to the agröecosystems. The sources of heavy metals in agricultural soil in most countries include natural source, mining, smelting, agrochemicals, sewage sludge applications, livestock manure, fly ash and waste water uses. In agriculture fields is commonly contaminated by using fertilizers. Systematic remediation technologies for contaminated soils are addressed as well, which include physical/chemical remediation, phytoremediation, microbial remediation and integrated remediation.