NEW DELHI: Politics over Chhath Puja and the polluted Yamuna apart, officials carrying out the spraying of an anti-surfactant on the foam in the Yamuna – which has been the picture postcard of Chhath that the Capital sends out annually – have vouched for the chemical’s safety and efficacy. Sanjay Sharma, director of Delhi Jal Board’s quality control wing, was on Friday overseeing the froth control work being undertaken at Kalindi Kunj as recommended by the special committee of National Mission for Clean Ganga (NMCG). Largely due to untreated waste and effluent from detergent factories entering the river, and in the absence of dissolved oxygen, swathes of froth form on the Yamuna. Officials revealed that the de-foamer being sprayed at Kalindi Kunj was polyoxypropelene, which has been declared to be safe by the United States Food and Drug Administration. Defending the exercise, Sharma, who is seen in the viral video of his spat with Parvesh Verma, claimed that an on-site fish toxicity test and fish bioassay had been carried out to be “doubly sure”. Another DJB official added, “This de-foamer is used worldwide and is completely safe. In fact, it was recommended by NMCG. In tests, fish from the river remained unaffected. In fact, we found the dissolved oxygen level rose and pollution dropped.” According to the fish bioassay, a report of which is with TOI, eight local Yamuna rohu and puthi fish were kept in 20 litres of defoaming chemical diluted 100 times for two to 12 hours without coming to any harm. The officials pointed out that the de-foaming agent, procured through a Coimbatore organisation, was proving good for the river’s health. “The chemical was tested in DJB’s laboratory for a month where it was discovered to be raising the dissolved oxygen level. The compound has been approved by FDA for use in waterbodies and effluent treatment plants to reduce froth,” said Sharma. A DJB official explained that “there could be two major reasons why foam is formed on the river. One, of course, because there are so many open drains discharging sewage into the river. The second is that the barrage at Kalindi Kunj has a big difference in water level that results in water flowing downstream causing turbulence. Were the water to be released from the barrage smoothly, froth formation would be minimised.” According to the officials, the first trial of the anti-surfactant spray was conducted on October 24. Since then, the dissolved oxygen level has increased on that stretch of the Yamuna. Spraying will continue there between 8am and 8pm for a few more days in an effort to prevent froth. However, river activist Manoj Mishra, pointed out in a tweet that the use of man-made polymers couldn’t be deemed eco-friendly. “Not contesting the intention though, why only now is a valid query; it can be asked how use of a man-made polymer ‘silicone’ with known toxic effects is dubbed eco-friendly,” tweeted Mishra. DJB officials explained, however, that the chemical had been diluted to a very safe level. Unlike every year, perhaps this year devotees who gather in large numbers on the Yamuna bank for Chhath Puja may not have to grapple as much with froth. It was last November that that chief minister Arvind Kejriwal had announced a six-point action plan to clean the Yamuna and said he would himself take a dip in the river before the next Assembly elections, in effect fulfilling a promise made by his party in 2020. But that’s easier said than done.
Source: https://timesofindia.indiatimes.com/city/delhi/use-of-chemical-boosted-dissolved-oxygen-reduced-pollution-official/articleshow/95153063.cms