New Delhi: India’s rivers have a heavy metal contamination problem. According to The Hindu, samples taken from two-thirds of water quality stations on major rivers revealed the presence of a heavy metal (or in some cases more than one) beyond limits specified by the Bureau of Indian Standards.
The Central Water Commission (CWC) collected a total of 442 surface water samples, of which 287 were polluted by heavy metals. “Samples from 101 stations had contamination by two metals, [and] six stations saw contamination by three metals,” the newspaper reported.
The most common heavy metal found was iron, and above safe limits in 156 samples. Lead, nickel, chromium, cadmium and copper were the other metals.
“Over the last few decades, the concentration of these heavy metals in river water and sediments has increased rapidly,” the CWC said in a report. It suggested increased monitoring of these levels. It has held “population growth and rise in agricultural and industrial activities” responsible for the contamination.
While some amount of metals in drinking water is normal and even required, if the level goes beyond the set limits it can lead to a range of diseases.
Long-term exposure can lead to “progressing physical, muscular, and neurological degenerative processes that mimic Alzheimer’s disease, Parkinson’s disease, muscular dystrophy and multiple sclerosis,” The Hindu reported.
The CWC study covered 67 rivers in 20 river basins, and across three seasons.
“Arsenic and zinc are the two toxic metals whose concentration was always obtained within the limits throughout the study period,” the CWC report says.
For other metals, contamination levels changes with the season. “For instance, iron contamination was persistent through most of the Ganga during monsoon but dipped significantly during the non-monsoon periods,” The Hindu noted.