K-G waterways most polluted

Catchment areas of the all important Krishna and Godavari rivers are among the most contaminated in the country. Research being conducted into trace metal contamination in catchment areas of major rivers has found that sediments in the Krishna and Godavari catchment areas have the highest mercury levels in the whole of the Indian coast.

Levels of other heavy metals, lead and cadmium, are also among the highest in these catchment areas. Much of the mercury could be from the many thermal power plants located there.

Scientists from the National Institute of Oceanography (NIO) are engaged in a research project to assess the contamination levels of estuarine sediments in catchment areas of major Indian rivers on the west and east coasts.

The project, under the Twelfth Five Year Plan (FYP), is being carried out by NIO scientists Dr Parthsarathy Chakrabarthy, Dr Darwin Ramteke, Dr Sucharita Chakraborty and Dr B. Nagender Nath.

Some rivers that are being assessed are the Ganga, Kaveri, Godavari, Krishna, Narmada, and Tapti. Dr Nagender Nath said, “We analysed about 200 samples from different catchment areas. Mercury is highest in Godavari and Krishna. These areas are highest in every metal contamination.”

DC CORRESPONDENT National Institute of Oceanography scientist Dr Nagender Nath said thermal power plants could be the source of mercury contamination in Krishna and Godavari rivers.

“Thermal power plants are probably the source of mercury contamination but we still have to analyse the samples for the source,” he said.

Lead and cadmium contamination was also the highest in the Godavari and Krishna rivers. The Pollution Load Index, which is used to evaluate contamination levels and pollution in coastal and estuarine sediments, was found to be higher in these two river estuaries.

Scientists have not pinned down the cause of the pollution to a particular source.

“We are still analysing the source. We can’t say for sure that it is entirely due to industrial pollution,” Dr Nagendra Nath said.

Scientists are also trying to find out the proportion of the trace metals that can enter the life cycle “We are assessing how much of it is bioavailable. Let’s say there is 10 ppm of lead, only about 5 ppm might be bioavailable and entering the life cycle,” Dr Nath said.