Hazardous Heavy Metal Pollution: Challenges and Solutions

Abstract

Hazardous heavy metals and minerals (fluoride, arsenic salts) pollution is a serious environmental problem. Many of these elements being stable are bio-accumulative and controlling them to their safe limits is very difficult. Also toxicity of metals depends largely on its chemical form and oxidation state. Some elements like Fe, Zn, Cu, Co, Cr, Mn, Ni, are needed in small quantities for human metabolism, but may be toxic at higher levels. Others like lead, mercury, cadmium, and arsenic etc. have no beneficial role and are very toxic and dangerous for human health. Small amounts of fluoride help to prevent dental caries but excess is harmful. Toxicity of these is of considerable concern in India because of their environmental burden. Due to the increasing use of a wide variety of metals in industry and in our daily life, problems arising from toxic metal pollution of the environment have assumed serious dimensions. The toxic metals are disposed in the environment through industrial effluent, organic wastes, refuse burning, transport and power generation. They are carried milles away from the sources by wind, depending upon whether they are in gaseous form or as particulates. Metallic pollutants are ultimately washed out of the air by rain on the land or in water ways. Phytoremediation is an emerging technology that employs the use of higher plants for the cleanup of contaminated environments. Potential for phytoremediation depends upon the interaction among soil, contaminants, microbes, and plants. This complex interaction, affected by a variety of factors, such as climatic conditions, soil properties and site hydrogeology argues against generalization and verdicts in favor of site-specific phytoremediating practices.