Role of forestry in mitigating global soil pollution from toxic heavy metals - a review

Abstract

One of the challenges confronting environmental management is the pollution of land, air and water resources by toxic heavy metals.This review seeks to identify the plant species and their potentials for remediation, less cost effective methods to remediate contaminated soils, and the remediation capability of woody plants. Soil pollution by heavy metals is a global problem. Globally, human activities lead to a substantial accumulation of heavymetals in soils. The accumulation of heavy metals comes from industrial activities like mining, smelting, refining, manufacturing processes and residues from excessive use of fertilizers. A lot of chemicals and heavy metals are released into the environment and contribute to a variety of toxic effects. Heavy metals such as Cadmium, Copper, lead, Chromium, Zinc and Nickel are serious environmental pollutants. The soil has been the disposal mediumfor most ofthe heavy metals. The soilneeds to be treated. Conventional remediation technique of cleaning heavy metals from contaminated soil is expensive and environmentally destructive. The use of plant species for cleaning polluted soils is gaining increasing attention.Use of plants to detoxify pollutants is a cheap, environmental friendly and effective way of cleaning contaminated soils. The mechanisms of metal uptake, accumulation, osmoregulation, and translocation vary with each plant species. The use of trees as a vegetation cover for the remediation of land contaminated by toxic heavy metals seemsmuch more effective. In order to overcome the problems of soil pollution, human beings have to reduce their impact on the environment seriously.Proper monitoring of industries handling toxic industrial wastes should be carried out regularly. Adapted tree species like Azadirachta indica and Adansonia digitata should be planted on contaminated sites such as mechanic sites to detoxify pollutants.

Keywords: Pollution, Remediation, environmental management, heavy metals, osmoregulation, translocation, detoxify