Groundwater Nitrate Contamination in India

January 2, 2025

India faces groundwater contamination issue, particularly due to excessive nitrates. The Central Groundwater Board (CGWB) reports that as of 2023, 440 districts have unsafe nitrate levels, up from 359 in 2017. This rise poses health risks, especially for children, and contributes to environmental toxicity. The data indicates that approximately 56% of India’s districts exceed safe nitrate limits, primarily due to nitrogenous fertilisers used in agriculture.

Current Groundwater Nitrate Levels

The CGWB collected 15,239 groundwater samples across India. Almost 19.8% of these samples contained nitrates above the safe limit of 45 mg per litre. This percentage is slightly lower than the 21.6% recorded in 2017. The increase in contaminated districts marks a growing concern regarding groundwater safety.

Regions Affected by Nitrate Contamination

Certain states report alarming levels of nitrate contamination. Rajasthan, Karnataka, and Tamil Nadu exhibit the highest rates, with 49%, 48%, and 37% of tested samples respectively exceeding safe limits. Other states like Maharashtra and Telangana also show contamination levels, indicating a troubling trend in central and southern India.

Seasonal Impact on Nitrate Levels

Monsoon rainfall influences nitrate levels in groundwater. Pre-monsoon testing showed 30.77% of samples contaminated, while post-monsoon testing revealed an increase to 32.66%. This seasonal variation puts stress on the need for monitoring and management strategies to mitigate contamination.

Other Chemical Contaminants

Fluoride and uranium also contribute to groundwater quality issues. Rajasthan, Haryana, and Karnataka report fluoride levels exceeding permissible limits. Furthermore, uranium contamination is a critical concern in Rajasthan and Punjab, with samples showing concentrations above 100 ppb, which is deemed unsafe.

Groundwater Extraction Trends

The CGWB estimates that groundwater extraction in India stands at 60.4%, consistent since 2009. However, there has been a notable increase in the number of ‘safe’ groundwater blocks, rising from 67.4% in 2022 to 73% in 2024. Despite this positive trend, the overall number of blocks analysed decreased by 343, raising concerns about data reliability.

Nitrate levels above 45 mg/l are hazardous.
56% of districts in India exceed safe nitrate limits.
Rajasthan has the highest nitrate contamination at 49%.
Uranium levels above 30 ppb are unsafe.
Groundwater extraction has been stable since 2009.

Addressing Groundwater Contamination

Efforts to address groundwater contamination must focus on sustainable agricultural practices. Reducing reliance on nitrogenous fertilisers can help lower nitrate levels. Additionally, improving water management strategies is essential to prevent overexploitation of groundwater resources. Regular monitoring and public awareness campaigns are crucial for protecting water quality and ensuring public health.

« Previous Post Next Post »