Activist flags excessive defoamer use in Delhi's Yamuna river

Acitivist Pankaj Kumar said this year, the usage of the defoamers has continued since October 15

A Yamuna activist on Tuesday wrote to lieutenant governor VK Saxena and Delhi chief minister Rekha Gupta, flagging excessive usage of defoamers in the Yamuna for a prolonged period, and highlighting possible adverse affects it may have on the river ecology and aquatic life.

Workers spraying defoaming agent on Tuesday. (Sunil Ghosh/HT Photo)

In a letter, activist Pankaj Kumar wrote that defoamers were used only for a brief period around Chhath Puja over the past few years, but this year, their usage has continued since October 15.

“This year, the activity began in the second week of October and continued unabated for over 60 days as of December 15, with plans to extend it for additional months. Personal observations confirm that defoamer is being sprayed in large quantities even when no foam is visible on the river surface, far exceeding any rational or temporary measure,” Kumar said in his letter dated December 15.

He cited international peer-reviewed studies, adding that these have established that excessive use of silicone-based (polydimethylsiloxane/PDMS) defoamers causes severe harm.

Apart from impacting aquatic life, Kumar said constant spraying will cause reduced oxygen transfer due to hydrophobic films on the water surface, leading to oxygen depletion; disruption of natural microbial activity; and accumulation of non-biodegradable silicone oils and silica particles in sediments, altering soil chemistry and harming benthic organisms.

While the Delhi Jal Board did not respond to HT’s queries, an official with the water minister’s office said that the issue had been brought to their attention and that instructions will be issued to stop the exercise.