‘Stop using herbicides in Powai lake’

MUMBAI: Acting on a complaint by a city-based environment group, the Maharashtra Pollution Control Board (MPCB) on Thursday sent a notice to the Brihanmumbai Municipal Corporation (BMC) asking it to stop spraying herbicides containing glyphosate in Powai lake to control the growth of water hyacinths, until further notice. MPCB also asked BMC to “submit any technical say towards use of this herbicide in the lake area”.

The civic body had in August floated a tender for removal of water hyacinths at Ganesh Ghat, Pawarwadi and other areas to make space for immersion activities during Ganesh Chaturthi. The work was later awarded to an organisation called Saguna Rural Foundation. According to a preliminary inquiry and site visit conducted by a field officer on September 15, “The said contractor has sprayed glyphosate as herbicide on Powai lake area from September 3 to 8.”

Glyphosate, a staple ingredient in herbicides, can pose adverse toxicological effects on flora and fauna, especially in aquatic ecosystems. Depending on the extent of use, it may lead to an increase in the water body’s phosphorus content, which in turn will lead to the proliferation of algae and exacerbate eutrophication. This can reduce the ability of zooplankton to reproduce for other biodiversity to thrive.

MPCB in their notice to BMC’s assistant commissioner of S ward also pointed out that the lake is a habitat for the Indian marsh crocodile, a species protected under the Wildlife (Protection) Act. Despite requests, assistant municipal commissioner of S ward, Ajit Kumar Ambi, and BMC’s chief engineer of hydraulics department Ajay Rathore did not respond to calls and messages seeking comment on Friday.

This action by MPCB comes on the heels of complaints raised by NGO Vanashakti, which had, on September 13, written to the pollution control board, BMC and forest department objecting to the use of herbicides in Powai lake. The next day, citizens living in the vicinity had reported that drones were being used to spray herbicide into far reaches of the lake, which MPCB officials corroborated during their visit on September 15. However, MPCB pointed out that the work was not underway on the specific date of their site visit.

Stalin D, director of Vanashakti, said simply removing these weeds is not enough to restore the health of the lake. “The water hyacinths no doubt reduce the levels of the lake and reduce its boundaries, but at the same time they also remove organic pollutants and heavy metals in the lake. If the hyacinths are removed without tackling the issue of pollution due to discharge of sewage, the move will be counterproductive,” Stalin said.

The herbicide is allegedly being sprayed to control the growth of water hyacinths in Powai lake.