In the News: City may ban all farming along Yamuna
From The Asian Age by Sanjay Kaw: 24 July 2014: New Delhi: With traces of toxic metals found in fruits and vegetables grown along the banks of the Yamuna river, the city administration is likely to ban farming with contaminated water from the river. The national capital receives 95 per cent of its vegetables and fruits from other states. Of the remaining five per cent, half of these are grown using the Yamuna’s polluted water. As the move to ban farming would render many farmers jobless, the city administration may allow the land to be used for farming of ornamental flowers.
Soon after the WHO dubbed Delhi as one of most the polluted cities, the city administration set up a high-level committee to tackle growing air and water pollution. The committee also deliberated on the farming of vegetables and fruits along the 22-km river as they were found to contain highly toxic metals, unfit for human consumption.
The city administration is also examining a study by The Energy Research Institute (Teri), which showed that the continuous dumping of untreated industrial effluent and sewage into the river had contaminated the riverbed soil, and vegetables grown along the river, especially the green leafy ones, were found to contain high levels of toxic metals.
The Teri report, titled Living in a Cleaner Environment in India: A Strategic Analysis and Assessment, said that levels of nickel, manganese and lead in the Yamuna water were found to be higher than the international aquatic water quality criteria for fresh water.
Lead has been known to impair motor skills and result in hypertension. Cadmium leads to renal damage, osteomalacia and loss in sense of smell. Leading international agencies on cancer have classified cadmium as a human carcinogen.
The study was based on 13 samples collected at a two-km distance along the 22-km stretch of the Yamuna in Delhi. The findings had revealed that green leafy vegetables contained the highest amount of metals.
Samples were also collected from Dayalpur and Chandawali villages in Ballabhgarh district of Haryana, about 25 km from Delhi, to compare with those collected from the urban sector.
The report revealed that the levels of nickel, manganese, lead and mercury were above the permissible international standards in agricultural soil long the river. While moderately high levels of contamination were recorded in urban areas, the rural belt relatively showed negligible levels.
The findings had revealed that green leafy vegetables contained the highest amount of metals. This was because such vegetables have a high tendency to accumulate metals. The study showed metal levels were significantly lower in other vegetables and practically negligible in the drinking water samples. The high levels of pollutants is being associated with treated and untreated effluents or with sewage flowing into the river.
The study identified Wazirabad and Okhla barrage as the hotspots for soil contamination. This was primarily possible due to the discharge of huge amounts of industrial effluents at the two locations from the Najafgarh and Shahdara drains.
The study revealed that vegetables grown in the floodplains of the Yamuna showed higher levels of heavy metal contamination than those cultivated in rural areas, thus, acting as the point of entry for toxic metals into human food chain. The bio-monitoring of women and children in the study area showed significantly higher levels of heavy metals in urine and blood samples taken in urban areas compared to the rural areas.
The report said that soil samples exceeded the limit for nickel and copper at most sites, and less often for zinc, manganese and lead. The quantity of lead varied from below-detection levels to 114.6 mg/kg, with some locations recording a prevalence more than 40 times the lowest level along the 22-km stretch. The chromium levels in soil samples at different locations ranged from 4.52 mg/kg to 35.29 mg/kg. Levels of more than 25 mg/kg were also found. The soil concentrations of mercury largely ranged between 0.43 mg/kg and 82.06 mg/kg. These levels were much higher than the 1 mg/kg stipulation at all the locations.