Prolonged use of chemical defoamers could further harm Yamuna: Activist to DJB

New Delhi, Nov 24 (PTI) Prolonged usage of silicone-based defoamers on the Yamuna may further worsen the health of the river further, alleged an environmentalist group in a letter to the Delhi Jal Board (DJB) on Monday.

For the past few years the DJB has sprayed a chemical solution on the surface of the Yamuna River near the Kalindi Kunj barrage to suppress the visible froth.

"In the past, the DJB restricted the spraying of polydimethylsiloxane (PDMS) defoamers downstream of the Okhla barrage to a brief seven to ten-day period immediately before and during the festival. This year the spraying of liquid began in the second week of October and is intended to continue for up to three more months," Pankaj Kumar, an environment activist, said in his letter.

This is no longer a temporary measure. It feels routine, and that is frightening, the letter read.

There was no immediate response from the DJB on the letter.

"PDMS forms a hydrophobic film that reduces oxygen exchange. Over prolonged periods, that can worsen an already stressed river," Kumar wrote.

Studies indicate that silicone oils degrade slowly, often accumulating in sediments and affecting bottom-dwelling organisms.

"Even if the defoamer formulation is claimed to be 'safe' when used in calculated microdoses, there is no safe limit when it is sprayed indiscriminately for weeks/months and in areas without foam," the letter added. PTI SSM SSM ARB ARB