Delhi will have to get its act together on groundwater pollution

A recent study by the Delhi University has revealed the presence of harmful chemicals and heavy metals in the city’s groundwater resources. If this groundwater is consumed, according to the study, it can lead to serious health problems in the nervous system, kidneys and the digestive tract.

Titled Groundwater Environment in Delhi, the study was conducted by the DU’s geology department to identify the nature of contamination across the city. As per the report, people living alongside the Yamuna or those living in industrial areas and near landfill sites are at a greater risk.

“We know at present Delhi has limited surface water resources for drinking purposes and its groundwater resources are being widely abstracted to meet industrial, agricultural and domestic needs. Today various critical issues are associated with the water resources in the national capital, including over-exploitation and pollution of groundwater. In this study, we have tried to find out overall groundwater environment and found presence of several chemicals and heavy metals in the groundwater across the city,” Shashank Shekhar, assistant professor, department of geology, DU, said.

According to a general physician, Dr B.K. Singh, exposure to polluted water can cause diarrhoea, skin irritation, respiratory problems and other diseases, depending on the nature of the pollutantsbeing consumed. “Stagnant water and other untreated water provide a habitat for mosquitoes and a host of other parasites and insects that cause a large number of diseases, especially in the tropical regions,” he said.

According to the study, a general assessment of groundwater quality of all the nine districts of the city reveals presence of contaminants such as fluoride, nitrate and lead. It revealed that the groundwater in the west Delhi district was more contaminated than other districts of the city.

Dr R.K. Singal, BLK Super Speciality Hospital’s head and director of internal medicine, said that contaminated water with high content of nitrate, lead, chloride, chromium etc. can lead to a number of health issues ranging from, gastro problems, typhoid, sore throat, respiratory tract infections, a slew of fungal and skin infections and a general fall in immunity.

“Excessive accumulation of these chemicals can lead to deposits on kidney which can lead to many kidney-related problems and even kidney failure in later stages. Contaminated water can also lead to brain-related problems like dementia, memory loss, types of diarrhoea, cholera, malaria and many more,” added Dr Singal.

“Groundwater salinity is a common problem in Delhi. The depth of the interface between fresh and saline water varies from area to area in the city. “Highly saline groundwater in the city is mainly due to waterlogging, low lying areas and discharge zones. Irrigation and waterlogging also cause an increase in concentration of chloride and nitrate ions in the groundwater,” said Prof. Shekhar.

The study also found that industrial areas located in the western, southern and eastern parts of the city as well as the three thermal power plants are the major anthropogenic sources of groundwater contamination. “Industrial and domestic effluents increase nitrate concentration in groundwater in some pockets of the west, southwest and northwest districts. These nitrate plumes in the groundwater in the southern and northern parts of the city are indication of urbanisation of these areas,” said Shakir Ali, research scholar, who co-authored the study.

High concentration of arsenic found in some areas is due to anthropogenic sources such as garbage from open landfill sites and arsenic contamination in the Yamuna floodplains is due to arsenic rich coal ash from the thermal power stations.

The study also pointed out that the contamination of the groundwater by trace metals is due to industrial waste in the Yamuna river catchment areas from the Najafgarh drain. “The use of water from the Yamuna river and its associated drainage systems for irrigation of agricultural land leads to an accumulation of heavy metals such as chromium, copper, zinc, lead, nickel and cadmium as a result of industrial waste and sewage in the subsurface,” added Prof. Shekhar.

“Heavy lead is hazardous to health as it accumulates in the body and affects the central nervous system. Children and pregnant women are mostly at risk. Similarly, excess and regular use of fluorides can cause yellowing of teeth, weakening of bones and damage to the spinal cord and may cause other crippling diseases. Presence of chemicals and heavy metal in groundwater is a serious health issue and if it is not addressed at earliest then it will make whole population and generations unhealthy,” said Ganga Ram Hospital’s gastroenterologist Naresh Bansal.