Sediment contamination due to toxic heavy metals in Mithi river of Mumbai - Paper published in the journal Advances in Analytical Chemistry

This paper published in the journal Advances in Analytical Chemistry discusses the findings of a study that aimed at quantification of accumulated toxic heavy metals in the sediments of Mithi river of Mumbai.The study was conducted at three different sampling locations along the flow of Mithi River for two years from 2009 to 2012. The different heavy metals studied were Al, As, Cd, Cr, Hg, Ni, Pb, Sr and Mn respectively.

Evidence indicates that among the inorganic contaminants of the river water,  heavy metals are the ones that cause the maximum negative impact on the body as they are non-degradable and often accumulate causing a deleterious biological effects. These toxic heavy metals create serious environmental problems owing to their long biological half lives and it is very difficult to remove them completely from the environment once they enter into it. 

The paper informs that rivers are one of the major pathways for transport of these heavy metals and recent evidence indicates that heavy metals have become significant pollutants of many riverine systems in the country. Anthropogenic activities like mining, disposal of treated/untreated waste effluents containing toxic metals as well as metal chelates from different industries and the indiscriminate use of heavy metal containing fertilizers and pesticides in agriculture have resulted in deterioration of water quality rendering serious environmental problems and posing a threat on human beings and the aquatic biodiversity.

Though some of the metals like Cu, Fe, Mn, Ni and Zn are essential as micro nutrients for life processes in plants and microorganisms, other metals like Cd, Cr and Pb have been found to be detrimental beyond a certain limit. These metals entering the ecosystem may lead to geoaccumulation, bioaccumulation, biomagnification and may get transformed into toxic forms. These toxic heavy metals entering in aquatic environment are adsorbed onto particulate matter or they can form free metal ions and soluble complexes that are available for uptake by biological organisms or get deposited in estuarine sediments.

The study found an increasing trend in the concentration of toxic heavy metals in the waters of the Mithi river over the two years. The paper ends by arguing that the present data on heavy metal pollution in sediment samples collected along the Mithi River of Mumbai points at the need for regular monitoring of water resources and further improvement in the industrial wastewater treatment methods. The paper argues for the need for a consistent, internationally recognised and data driven strategy to assess the quality of aquatic bodies and generation of international standards for evaluation of levels of contaminants in the waters in the country.

The paper can be accessed at this link