New Delhi, Jan 15 (India Science Wire): River pollution is a cause of concern in India as almost 45 rivers
have at least two toxic heavy metals beyond the permissible limits. A group of researchers from
Bharathidasan University, Tamil Nadu, has found that several anthropogenic activities in the recent
decades have led to the deposition of metal and other pollutants in Cauvery river basin in Tamil Nadu
In the study, traces of elements were detected in water and soil samples of the Cauvery river basin,
which might be influenced by several anthropogenic activities. Among other reasons, seasonal idol
immersion activity was reported as one of the main sources of pollution. The concentration factor and
geo-accumulation index revealed that soil samples of the Cauvery river basin were highly contaminated
by Cadmium. The presence of other metals was less. “The immersion of the seasonal idol may not
create any strong impacts on the distribution of metal in the Cauvery river because of its streamflow.
However, when the river water ends up into the sea, these metal pollutants arising from the immersions
of idols would have a negative impact in the waters and sediments of the Bay of Bengal” says the
published research paper.
In the study, a total of 29 water and topsoil samples were collected from the Cauvery basin before and
after idol immersion, and were evaluated for the presence of metals. The experimental results showed
elevated Cadmium and Lead levels in water and sediment samples of both Cauvery and Kollidam rivers.
Strong statistical significance was observed for all the elements studied in the soil samples collected
before and after idol immersion (P < 0.01). Industrial effluents, textile waste, untreated sewage,
municipal waste and agricultural activities are the most common causes of elevated levels of heavy
metals in the study area.
Further, geo-accumulation index and pollution load index studies showed lesser impact of idol
immersion on metal distribution compared to other sites reported from India. The concentration of
heavy metals varied for different stations, which could be attributed to idol immersion activity or any
other source of pollution. However, strict regulatory policies of the concerned authorities help maintain
the quality of the Cauvery basin.
The research team includes Rajaram Rajendran, Vinothkannan Anbazhagan, Ganeshkumar Arumuga and
Arun Ganeshan. The research findings have been published in the journal Current Science. (India Science
Wire)
Keywords: Cauvery river basin, heavy metal pollution, metal pollutants