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Updated: Aug 29, 2019 08:09 IST

Excessive use of fertilisers and pesticides by farmers on the Yamuna’s floodplains is contributing to poisoning the river water, its floodplains and groundwater, a new report by the Central Pollution Control Board (CPCB) has revealed.

Metals such as copper, lead and manganese were found in the river, while groundwater contained high levels of iron and manganese. According to a senior CPCB official, in some places, aluminium, arsenic and chromium were found to be exceeding safe limits.

Only 2% of the river passes through Delhi but receives nearly 76% of its entire pollution from here, mostly attributed to untreated industrial and domestic waste. The CPCB reporting the excess use of fertilisers, which contains trace amounts of these metals as micronutrients for crops, and pesticides contributing to polluting the river water, groundwater and the floodplain soil, however, is a first.

The apex pollution control body has recommended farming be controlled on the floodplains, and farmers be discouraged from growing such vegetables and fruits that absorbs more metal. The CPCB has also recommended use of organic farming and biological control of pests along with training of farmers to bring down the use of chemicals.

“Metals like copper, lead and manganese was found to be exceeding drinking water standards in the entire stretch of the river. In the ground water, while iron and manganese were found to be predominant, the water was contaminated with aluminum, arsenic and chromium in some places. Copper, zinc and lead was found to be exceeding safe standards in the entire floodplains,” said a senior CPCB official.

Even though the study didn’t find any metal content above safe limit in the vegetables grown on the floodplains, HT had reported in July that a separate study conducted by the NEERI had found high doses of lead in vegetables. The heaviest lead contamination was found in coriander leaves collected from Geeta Colony.

“Leafy vegetables such as spinach, vegetables that grow below the ground or close to the ground such as carrot, radish and turnip and vegetables that grow faster tend to absorb more metals from the soil and water. The government should ban growing any edible items in such soil and water. Ornamental plants, flowering plants or cash crops can be allowed to grow,” said BS Tomar, head of the vegetable sciences department at Indian Agricultural Research Institute in Pusa.

Both studies were commissioned by the NGT-appointed Yamuna pollution monitoring committee led by Shailaja Chandra and BS Sajwan after a HT report on vegetables grown on the river’s floodplains on February 4, 2019. The studies have been submitted before the monitoring committee. The committee is expected to submit the report to the NGT with its observations.

“The presence of iron and manganese is common and not a major concern. Even the ground water quality below the floodplains is very good barring a few pockets. What is alarming is the presence of such metals in the soil. If not checked, these metals could enter the food chain,” said Shashank Shekhar, assistant professor of geology in Delhi University.

During the study the CPCB team divided the river into three stretches — Palla to Wazirabad (stretch I), Wazirabad to Nizamuddin (stretch II) and Nizamuddin to Okhla (stretch III). Samples of vegetables and fruits such as zucchini, okhra, spinach, lobia, sitafal, brinjal, pumpkin, chilly, lady’s finger and bottle gourd among others were collected randomly from the three stretches along with samples soil, groundwater and river water. They were then analysed in NABL accredited laboratories and the report was submitted to NGT in July.

“It is concluded that the contamination of soil was observed at most of the monitoring sites, which may be due to excessive use of fertiliser. However, water quality depicts trace amount of metals at some locations primarily due to industrial wastewater discharge,” said the CPCB report.

The peasant’s society in Delhi has welcomed the suggestions made, saying that training of farmers is indeed needed to bring down use of chemicals.

“Presence of metals in vegetables and fruits is not just Delhi’s problem. If the vegetables, entering Delhi’s sabzi mandis from outside the city are tested, metals can also be found in them. Farmers should be made aware and trained to reduce use of chemical fertilisers. Organic farming is also a good option,” said Dalbir Singh, vice president of Delhi Peasants Multi-purpose Society.