Groundwater Pollution

Groundwater Pollution

Context

A Parliamentary Standing Committee recently flagged a public health crisis involving groundwater contamination in 4,949 villages across 8 Indian states. The report highlights a dangerous surge in heavy metals, fluoride, and nitrates, threatening the safety of drinking water and agricultural productivity.

About the News

Definition:

Groundwater pollution occurs when pollutants such as chemicals, heavy metals, and pathogens which seep into aquifers and underground water-bearing layers. Unlike surface water, groundwater moves slowly and has a limited self-cleaning capacity, making contamination difficult and expensive to reverse.

Key Data & Statistics:

• Affected Regions: Contamination is concentrated in Assam, Bihar, Kerala, Odisha, Punjab, Rajasthan, Tripura, and West Bengal.
• State Analysis: Rajasthan holds the highest number of affected districts. In Punjab, districts like Patiala and Ferozepur report presence of Mercury, Uranium, Selenium, and Cadmium.
• Contaminant Trends: Monitoring over the last five years shows a sharp increase in:
  • Electrical Conductivity (EC): Indicating high salinity.
  • Fluoride (F): Often naturally occurring but exacerbated by over-extraction.
  • Nitrate ($NO_3$): Primarily from agricultural runoff and sewage.
• Compliance: CPCB (Central Pollution Control Board) investigations found multiple samples failing pH standards for safe drinking water.

Major Pollutants and Their Sources

• Heavy Metals (Arsenic, Mercury, Uranium): Resulting from industrial discharge, mining activities, and geological leaching.
• Nitrates: Derived from the excessive use of chemical fertilizers and untreated domestic sewage.
• Fluoride: Linked to the weathering of rocks; levels often rise as water tables drop due to over-extraction.
• Salinity: Increased by over-pumping of coastal aquifers (leading to seawater intrusion) and poor drainage in irrigation.

Implications

• Health Hazards:
  • Fluorosis: Leading to skeletal and dental deformities.
  • Kidney & Neurological Damage: Caused by heavy metal toxicity (e.g., Mercury and Cadmium).
  • Cancer Risk: Particularly linked to Arsenic and Uranium exposure.
• Economic Impact: Polluted aquifers reduce the availability of potable water, forcing rural populations to spend more on healthcare and private water sources.
• Agricultural Safety: Contaminated water enters the food chain via irrigation, potentially making crops unsafe for human consumption.

Way Forward

• Strengthened Monitoring: Expand the network of observation wells and use real-time sensors for EC and Nitrate levels.
• Regulation of Extraction: Strictly implement the Central Ground Water Authority (CGWA) guidelines to prevent the concentration of pollutants caused by falling water tables.
• Remediation Technology: Deploy community-level purification plants (e.g., Arsenic/Fluoride removal filters) in the 4,949 identified villages.
• Sustainable Farming: Promote Organic Farming and efficient irrigation (drip/sprinkler) to reduce nitrate leaching from fertilizers.

Conclusion

Groundwater is a "hidden resource," but its contamination is becoming a visible crisis. Addressing the Parliamentary Committee's concerns requires a shift from mere extraction management to a holistic Water Quality Management framework that protects both the environment and public health.