The role of phytoremediation in the soil

Abstract

Pollution of our environment with heavy metals as a result of industrialization and use of agrochemicals to boost agricultural production is continuing unabated and is affecting animal and human health. As system of intensive agriculture is developing near the cities and making use of high doses of fertilizers and sewage sludge, Government and Public Opinion in world has started questioning the possible impact of these agro-chemicals and agricultural practices on the three components of our “Biotope”: Soil, air and water (Environment). Soils generally contain low levels of toxic heavy metals viz., cadmium (Cd), Mercury (Hg), Lead (Pb) and Nickel(Ni) but considerable amounts of the elements can be introduced into soils via anthropogenic pathways such as dumping industrial effluent and agricultural application of sewage sludge, use of inorganic and organic agro-chemicals, application of commercial fertilizers. In addition to above mentioned key sources of heavy metals contamination in soil, the products used in our modern society are also too toxic to be disposed off without particular treatment. Not only the industries generate such kind of poisonous and hazardous waste but also many household products fall under this category. If not disposed away correctly, some cleaners, solvents, pesticides, paints in the form of sewage water can contaminate the agricultural soil in the vicinity of cities, leak into the underground water or contaminate the irrigation sources resulting in tremendous risks for the safety and health of human. In the respect of our environment, the basic recommendations of (reduce, recycle, reuse) should prevail as a prevention, instead of curing. As good as it can be applied, this principle cannot totally avoid generation of hazardous waste and therefore, long term solution must be developed. For sustainable clean ups of environment from these hazardous wastes and heavy metals, techniques and strategies includes phytoremediation. It is a three step process involving high uptake of heavy metals by roots, transportation to shoot and sequestration (distribution) of metal within the shoot. Hyper accumulator plant species exhibit the shoot/root ratio of metal content greater than 1, which reflect that specific internal system pumps metals from plant roots to shoot tissue (8).The chelator-assisted phytoremediation studies has been carried out on the phytoremediation of Cd, Ni, Pb and Hg polluted soils by Brassica species under screen house condition in spiked soils in the Department of Soil Science, CCS Haryana Agricultural University Hisar-India.