Toxic heavy metals, high salinity found in groundwater, says report | Latest News Delhi

The rampant use of boreholes – often illegal – in the capital could have unintended health consequences, as a study found the presence of heavy metals, such as manganese, iron and even uranium, outside permitted limits in groundwater testing in some areas of Delhi.

While experts say that the occasional use of this water for bathing is largely harmless, drinking it can in the long run lead to chronic toxicity and influencing organs such as the kidneys or intestines. There are more than 8,000 unsealed boreholes left in the capital, with officials saying the process of sealing them will take more than a year.

The Central Groundwater Board (CGWB)’s latest annual report for 2020-21, released in August 2021 following data collection in May 2020, found the presence of uranium above the allowable limit of 30 parts per billion (ppb) at five locations within the city including Janakpuri, Harewali, Jharoda Kalan, Nizamuddin Bridge and Kanjhawala. The uranium concentration was found as high as 128.9 ppb in Jharoda Kalan.

Similarly, manganese levels found more than four times the allowable limit in parts of Delhi, with a peak of 1.39 parts per million (ppm) at Ujwa in southwestern Delhi, compared to an allowable limit of 0.3ppm, while iron was found to exceed the permitted limit of 1mg / liter at four locations in Delhi – Najafgarh, Nangli Rajpura, Ujwa and Bhalswa.

Delhi receives about 945MGD of tap water against a demand of 1150MGD, according to the Delhi Jal Board. To be sure, the study only mentions groundwater that was directly extracted, apparently by residents to make up for the 200MGD shortfall.

While heavy metals in small amounts are tolerable to the human body, their consumption and accumulation over the years can lead to organs developing problems, experts said.

According to the report, seen by HT, the groundwater in Khera Kalan in north Delhi, Rohini’s sector 28, Majara Dabas in northwest Delhi, Sanjay Van, Vikaspuri in west Delhi and Jhuljhuli in southwest Delhi have high fluoride levels above 1.5mg / liter that It is likely to cause erosion of the tooth enamel and stiffness in the bones. While a range of 0.8 to 1.2 mg / liter helps protect teeth, levels above 1.5 mg / l are enough to start enamel and over 5 mg / liter can cause bone stiffness over time , said the report.

Nitrate compounds, for the most part the leaching of chemical fertilizers, were found outside the Bureau of Indian Standard (BIS) limit of 45mg / liter in large parts of northwestern, central and southern Delhi districts, and high electrical conductivity (EC) – a sign salinity – was found in parts of Tagore Garden, Nizampur, Jharoda Kalan, Hiran Kudna and some pockets of Shahdara, where EC values ​​were high, even at shallow depths.

Suresh Rohilla, program leader at the International Water Association (IWA), said due to the large gap in supply and demand, many parts of Delhi are dependent on groundwater, the extraction of which not only causes a drop in the water table but also causes health consequences when consumed.

“About 95% of the groundwater that is extracted is for non-potable purposes, where the presence of heavy metals and other elements is not a big problem, but in cases where … it is consumed, then “These heavy metals can really affect the individual. In such cases, a water purifier is also not commonly used, so it is unclear what is consumed and in what quantities,” said Rohilla, noting that there was a need to educate people. about groundwater extraction, especially to ensure that the water table did not fall lower.

Professor Shashank Shekhar, from the Department of Geology at the University of Delhi (DU), who conducted a study to assess heavy metals in groundwater in 2017, found a high iron concentration along the Yamuna floodplains, which he thinks is a part is due to human resources.

“Expanded agriculture and urbanization have led to the release of various pollutants into the river as well as the groundwater system. While the iron concentration could already be high, human resources include leachate and sewage, in addition to industrial waste,” he said.

This in turn can be traced back to humans through multiple sources, including vegetables grown along the plains. In 2019, a study by the National Environmental Engineering Research Institute (NEERI), following an order from the National Green Tribunal (NGT), found the presence of heavy metals in vegetables grown along the Yamuna floodplains in Mayur Vihar, Usmanpur and Geeta Colony. The vegetables, especially cabbage, cauliflower, radish, brinjal and fenugreek, contained metals such as lead, nickel, cadmium and mercury in high concentration.

Manoj Mishra, environmentalist and meeting of the Yamuna Jiye Abhiyaan, said groundwater recovery remains a problem in the city, with the Yamuna being equally polluted by human interventions in most locations. “While these elements and heavy metals can be found naturally underground, human resources such as leachate or effluents entering the groundwater can also be factors,” he said, adding that high concentrations of chromium and arsenic were found in the groundwater. in areas where flying is dumped in Delhi.

Dr (Col) Vijay Dutta, internal medicine and respiratory medicine at the Indian Spinal Injuries Center (ISIC), said that consuming contaminated water can lead to transmission of diseases such as cholera, diarrhea, dysentery, hepatitis A, typhus and polio, with heavy metal handling poses the greatest risk. “While some of these heavy metals themselves are essential for growth, development and health, they are only required in small amounts. Meanwhile, there are other heavy metals, such as uranium, that are non-essential because they are indestructible. “and are toxic to our body. Prolonged exposure to such heavy metals can lead to serious health problems such as cancer and organ damage,” he said.

According to a survey conducted by the Delhi Jal Board (DJB) in 2019, following another NGT order, it was discovered that there are 19,661 illegal borewells in Delhi. While a report by Delhi Pollution Control Committee (DPCC) on October 25, 2021 said that 11,634 borewells have so far been sealed by the Department of Revenue, the process to seal the remaining 8,000 could take almost a year.

“An environmental compensation of 70.6 crore has been charged by us on these illegal borewells. So far, an amount of 54 lakh has been recovered, and the process of sealing more such units and recovering the remaining amount is still ongoing, “said a senior DPCC official.

A DJB official said several projects were planned to bridge the gap between demand and water supply, including plants for the use of unused Yamuna water part from Himachal Pradesh; wastewater exchange with UP in which Delhi treated wastewater will be supplied for irrigation in exchange for 140MGD raw water; and the Palla project, based on Singapore’s NeWater model in which highly treated water from a coronation plant is lifted and put back into the Palla River. “While wells are being closed, we also plan to develop a large number of water extraction points in areas with very high groundwater levels to increase supply,” the official said.

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