By admin 
High nitrate levels have been found in the groundwater of 440 districts across India, with 20% of the samples collected exceeding the permissible nitrate concentration, the Central Ground Water Board (CGWB) said in a report.
Nitrate pollution is a significant environmental and public health problem, especially in agricultural areas where nitrogen fertilizers and animal waste are used.
The ‘Annual Groundwater Quality Report – 2024’ also found that 9.04% of samples had fluoride levels above the safe limit, while 3.55% showed arsenic contamination.
In May 2023, a total of 15,259 measuring locations were selected nationally to monitor groundwater quality. Of these, 25% of the wells (the riskiest according to BIS 10500) have been examined in detail. Groundwater was sampled at 4,982 trend stations before and after the monsoon to see how recharge affects quality.
The report found that 20% of water samples exceeded the nitrate limit of 45 milligrams per liter (mg/l), the threshold set by the World Health Organization (WHO) and the Bureau of Indian Standards (BIS) for drinking water.
Rajasthan, Karnataka and Tamil Nadu had more than 40% of samples above the limit, while there was high contamination in samples from Maharashtra at 35.74%, Telangana at 27.48%, Andhra Pradesh at 23.5% and Madhya Pradesh with 22.58%.
Uttar Pradesh, Kerala, Jharkhand and Bihar reported lower rates.
In Arunachal Pradesh, Assam, Goa, Meghalaya, Mizoram and Nagaland, all samples were within safe limits.
In states like Rajasthan, Madhya Pradesh and Gujarat, nitrate levels have remained stable since 2015. However, Uttar Pradesh, Tamil Nadu, Andhra Pradesh and Haryana showed increasing infections between 2017 and 2023, the CGWB said.
Read more: Arsenic is found in groundwater in 19 districts of Assam. Here’s how it affects human health
High nitrate levels can cause health problems, such as blue baby syndrome in infants, and are unsafe to drink.
Fifteen districts in India have been identified as most affected by high nitrate levels in groundwater, including Barmer and Jodhpur in Rajasthan; Wardha, Buldhana, Amravati, Nanded, Beed, Jalgaon and Yavatmal in Maharashtra; Rangareddy, Adilabad and Siddipet in Telangana; Villupuram in Tamil Nadu; Palnadu in Andhra Pradesh; and Bathinda in Punjab.
High nitrate levels in groundwater can result from excessive irrigation, which allows nitrates from fertilizers to penetrate deep into the soil, the report said.
Poor management of animal waste in livestock farming contributes to the problem because it releases nitrates into the soil.
Urbanization and population growth are increasing wastewater and sewage, which often contains high levels of nitrate, while leaking septic systems and poor sewage disposal worsen pollution.
The report further said that fluoride concentrations exceeding the permissible limit are a major problem in Rajasthan, Haryana, Karnataka, Andhra Pradesh and Telangana.
Elevated arsenic levels (more than 10 parts per billion) were found in several states, especially in the floodplains of the Ganga and Brahmaputra rivers.
This includes the regions of West Bengal, Jharkhand, Bihar, Uttar Pradesh, Assam and Manipur, as well as areas in the Punjab and Rajnandgaon districts of Chhattisgarh.
Long-term exposure to fluoride and arsenic contaminants can have serious health consequences, including fluorosis (from fluoride) and cancer or skin lesions (from arsenic).
Also a major concern in the groundwater quality report was elevated uranium levels in several regions.
Forty-two percent of the samples with uranium concentrations above 100 ppb (parts per billion) came from Rajasthan, and 30% from Punjab, indicating regional hotspots of uranium contamination, the report said.
Chronic exposure to uranium can lead to kidney damage.
Read more: Gujarat to Delhi, these states and UTs have extracted more groundwater than others
According to the report, groundwater samples with uranium concentrations above 30 ppb are clustered in areas identified as over-exploited, critical and semi-critical groundwater stress zones, such as Rajasthan, Gujarat, Haryana, Punjab, Tamil Nadu, Andhra Pradesh and Karnataka.
“This overlap highlights the worsening effect of overexploitation and deepening water levels on uranium pollution in these regions,” the CGWB said.
Rajasthan, Delhi, Gujarat, Haryana, Punjab, Telangana, Andhra Pradesh and Karnataka are the worst affected by high electrical conductivity values in groundwater.