Chapter 12 - Current status of available techniques for removal of heavy metal contamination in the river ecosystem

Abstract

Heavy metal contamination in river ecosystem is a worldwide problem that is of great environmental concern. These heavy metals concentration in river water has expanded rapidly over the last few decades. As indicated by a Central Water Commission study, India’s 42 rivers have at least two heavy metals in excess of the safe limit. Ganga, India’s National River, has been found to be polluted with five heavy metals, namely Fe, Ni, Cu, Cr and Pb. Other than Ganga, more concentrations of these metals were found in Arkavathi, Orsang, Rapti, Sabarmati, Saryu, and Vaitarna. Moreover, it is of more concern because they disturb the ecological stability of river ecosystems due to its long-term negative influences. Consequently, concentrations of toxic metals have increased at alarming rates in grains and vegetables grown in contaminated soils. Because of its toxicity, non-biodegradability, and bioaccumulation it poses a serious threat to humans and the environment. Membrane filtration, reverse osmosis, chemical precipitation, charcoal/activated carbon adsorption, phytoremediation and biosorption have been widely used techniques for treatment of wastewater. The present chapter attempts to provide the status of these techniques and scenario of river ecosystems with respect to heavy metal contamination.