Ganga Among Top 10 Rivers Carrying Plastic Pollutants to Sea

Up to 95 per cent of the plastic pollution in the world’s oceans comes from only 10 rivers, eight of them Asian — including the Ganga river — and two African, according to a recent study. Water pollution has become a chief concern due to growing industrialization as many industrial units are set up on the banks of rivers. Not only do industries not check effluents but they also dump waste into the river, which leads to pollution in the oceans.

A study published in the Environmental Science & Technology journal said that large rivers contribute to water pollution more than smaller ones. “The concentrations of plastic, i.e. the quantity of plastic per cubic meter of water are significantly higher in large rivers than small ones. The plastic loads consequently increase at a disproportionately higher rate than the size of the river,” Christian Schmidt, a hydrogeologist at the Helmholtz Centre for Environmental Research – UFZ in Leipzig, Germany, said. “Halving the plastic input from the catchment areas of these rivers would already be a major success,” he added.

Schmidt pointed out the need to improve the waste management and raise public awareness for the issue. “We hope that our study will make a contribution to a positive development so that the plastic problem in our oceans can be curbed in the long run,” he said.

According to the study, rivers contribute between 410,000 and 4 million tonnes a year to the plastic waste in oceans. As much as 85-95 per cent pollutants are carried into oceans by 10 rivers — the Yangtze, Yellow, Hai He, Pearl, Amur and Mekong in east Asia, the Indus and Ganges Delta in south Asia, and the Niger and Nile in Africa.

The Helmholtz Centre for Environmental Research conducted the study by analyzing various scientific researches that examined the plastic load — the quantity of plastic carried by the water — in rivers. Then they converted the results of the studies into mutually comparable datasets and determined the ratio of these figures to the quantity of waste that is not disposed off properly in the respective catchment area.

“We were able to demonstrate that there is a definite correlation in this respect,” Schmidt said. “The more waste there is in a catchment area that is not disposed off properly, the more plastic ultimately ends up in the river and takes this route to the sea.”

Earlier studies have revealed that rivers carry almost 1.15-2.41 million tonnes of plastic into the sea every year.

An earlier study done by The Ocean Cleanup, a Dutch foundation working on new technologies to rid the oceans of plastic, said that the Ganga was the second-most polluting river in the world, after the Yangtze River that runs through Shanghai, one of China’s most populous areas. The study stated that 66.67 per cent pollutants entering oceans come from 20 rivers, most of which are in Asia.