Groundwater Contamination in India: An Overview

Context:

Recently a study conducted by Duke University, USA and Central Groundwater Board of India has found widespread uranium contamination in groundwater from aquifers in 16 Indian states.

What is groundwater?

Ground water is the water that seeps through rocks and soil and is stored below the ground.

Groundwater resource and Use in India- Fast Facts:

  • Total usable water resources- 1,123 BCM/year; out of which share of surface water is 690 BCM/year and that of groundwater is 433 BCM/year
  • After keeping aside 35 BCM/year for natural discharge, the net annual ground water availability for the India is 398 BCM. Natural discharge occurs as seepage to water bodies or oceans in coastal areas and as transpiration by plants whose roots extend up to the water table.
  • Components of Groundwater Extraction and Use

Depletion of Groundwater

  • According to a recent Central Ground Water Board (CGWB) Report, Punjab was found to be the highest groundwater exploited state in India followed by Rajasthan, Delhi and Haryana
  • According to a 2016 Parliament committee report on water resources, nine states – in south, west and central India- groundwater levels are now described as “critical”
  • “Critical” implies a stage where 90 per cent of groundwater has been extracted, with significant decline in recharge capability
  • 16 states and two Union Territories were categorised as “over-exploited”, which means 100% of groundwater has been drawn, with little chance of recharge

Groundwater Contamination:

Ground water contamination is the presence of certain pollutants in ground water that are in excess of the limits prescribed for drinking water

Extent of Groundwater Contamination in India:

  1. Arsenic:
  • West Bengal, Bihar, Chhattisgarh, Assam and Uttar Pradesh.
  • The permissible limit according to the Indian standards for drinking water is 1.5ppm/l
  1. Fluoride:
  • Andhra Pradesh, Bihar, Gujarat, Haryana, Karnataka, Kerala, Madhya Pradesh, Maharashtra, Orissa, Punjab, Rajasthan, Tamil Nadu, Uttar Pradesh and West Bengal.
  • Permissible limit according to Indian standards is 50ppb/l
  1. 3. Iron: Assam, West Bengal, Orissa, Chhattisgarh, and Karnataka. Localized pockets in Bihar, UP, Punjab, Rajasthan, Maharashtra, Madhya Pradesh, Jharkhand, Tamil Nadu, Kerala and North Eastern States
  2. Uranium:
  • 16 states in north western, southern and south-eastern India. High prevalence in Rajasthan and Andhra Pradesh
  • WHO and US Environmental Protection Agency (EPA) standards for uranium level for safe drinking water: 30 micrograms of uranium/litre
  • However, in India Uranium is not included in list of contaminants monitored in drinking water specifications provided by the Bureau of Indian Standards
  1. Nitrate:
  • Andhra Pradesh, Bihar, Delhi, Haryana, Himachal Pradesh, Karnataka, Kerala, Madhya Pradesh, Maharashtra, Orissa. Punjab, Tamil Nadu, Rajasthan, West Bengal and Uttar Pradesh.
  • Permissible level is 45 ppm/l
  1. Salinity:
  • Inland: Rajasthan, Haryana, Punjab and Gujarat; to a lesser extent in Uttar Pradesh, Delhi, Madhya Pradesh Maharashtra, Karnataka, Bihar and Tamil Nadu.
  • Coastal: Minjur area of Tamil Nadu, Saurashtra Coast, Subarnrekha, Salandi, Brahamani outfall regions of Odhisa, Pondicherry, Sundarban region

Causes of groundwater Contamination

  1. Natural:
  • Groundwater naturally contains impurities due to nature of geological formations.
  • Natural arsenic pollution occurs because aquifer sediments contain organic matter that generates anaerobic conditions in the aquifer, thus releasing arsenic
  • Occurrence of fluoride is close related to the abundance and solubility of fluoride-containing minerals such as fluorite
  • In India, uranium concentration is also related primarily to natural causes
  1. Agriculture:
  • Intensive use of chemical fertilizers in farms result in leaching of the residual nitrate causing high nitrate concentrations in groundwater
  • Excessive and improper irrigation prcatices
  1. Industrial Waste:
  • Industrial effluents and municipal waste seeps through the soil and pollutes the groundwater.
  • Toxic industrial waste releases traces of heavy metals such as lead, cadmium, zinc and mercury.
  • Brine disposal from the petroleum industry, mine wastes, deep-well disposal of liquid wastes
  • leaky underground gas tanks
  • Sludge disposal
  • Example: Shallow aquifer in Ludhiana city is polluted by a stream which receives effluents from 1300 industries.
  1. Municipal waste:
  • Pollution by landfills, septic tanks
  • Indiscriminate disposal of human and animal waste on land; faulty onsite sanitation structures
  • leaky sewer lines
  1. Indiscriminate extraction of groundwater
  • Indiscriminate extraction of groundwater for irrigation purposes has led to inland salinity problem in parts of Punjab, Haryana
  • Excessive withdrawal of groundwater from coastal aquifers has led to induced pollution in the form of seawater intrusion. For example: In Kachchh, Gujarat
  • Uranium contamination has aggravated by groundwater-table decline. Decline in groundwater table induces oxidation conditions. As a result, uranium enrichment in shallow groundwater is enhanced.

Impact of Groundwater Pollution

  1. Health Impact:
  • Poor drinking water quality results in various diseases. For example, arsenic poisoning can lead to skin diseases, gastro-intestinal diseases and cancer
  • Fluoride contamination leads to damaged joints, bone deformities, flurosis
  • Prolonged intake of high Iron content water can cause haemochromatosis.
  • Consumption of water containing high levels of Nitrate can be a cause for some types of Cancer. It can also cause the Blue baby syndrome which affects new born babies
  • Viral and bacterial diseases due to contamination of groundwater by mixing of sewage and infiltration from latrine pits
  1. Soil and Agriculture:
  • Contamination of groundwater leads to reduction in soil quality and affects productivity
  • High salinity has resulted in decrease in agricultural productivity. Example: in Punjab and Haryana
  1. Economic:
  • High clean up costs
  • High costs for alternative water supplies
  • Increased disease burden- higher costs for health
  1. Environment:
  • Groundwater pollution can cause certain types of nutrients that are necessary in small amounts to become far too abundant to sustain normal life in a given ecosystem.
  • When groundwater that supplies lakes, rivers, streams, ponds, and swamps becomes contaminated, this slowly leads to more and more contamination of the surface water

Government Initiatives

  1. Groundwater (Sustainable Management) Bill, 2017
  • The bill proposes a new regulatory framework based on the recognition of the unitary nature of groundwater pool
  • It highlights the need for decentralised control and the necessity to protect water at the aquifer level.
  • It recognizes water as a public trust and a fundamental right
  • It seeks to give regulatory control over groundwater resources to local bodies.
  1. Water (Prevention and Control of Pollution) Act, 1974
  • Main objective: to provide for prevention, control and abatement of water pollution and the maintenance or restoration of water resources
  • The Act prohibits any person from releasing any poisonous/polluting matter, directly or indirectly, into any stream/ well/sewer/ land
  1. Initiatives to Combat Arsenic Contamination- West Bengal
  • Arsenic Task Force set up.
  • 2005- Setting up of Arsenic Removal Units (ARUs). These were reported as one of the finest performing devises and capable to remove arsenic from very high level of contamination.
  1. Salinity Ingress Prevention Scheme, Gujarat
  • Regulates lifting underground water
  • Provisions for recharge dam/ recharge wells
  • Change in cropping patterns
  • Fresh water barriers
  • Rejuvenation of salinity land of oceanic area
  1. Environmental Protection Act, 1986
  • The Act prohibits a person carrying on any industry, operation or process from discharging or emitting water pollutants in excess of the prescribed standards
  1. National Project on Aquifer Management:
  • Objective: to achieve equitable, safe and sustainable management of India’s groundwater resources through improved systems of resource mapping, utilization and governance.
  • Mapping of aquifers can help determine the quantity as well as quality of groundwater

Issues with Management

  • Central Pollution Control Board and the CGWB do not carry out real-time monitoring of water pollution in rivers, lakes and ground water sources.
  • The network of monitoring stations is not dense
  • Water quality analysis excludes critical parameters that help detect pollution by fertilizer and pesticide, heavy metals and other toxic effluents
  • Lack of regulation for over-extraction of groundwater resource Rules on groundwater access give landowners the right to pump on their land. However, landowners are not legally liable for any damage caused to the water resources as a result of over extraction
Best Practice:

Australia:

  • Extractions are metered, and compliance promoted through hefty fines for violation for corporations (for up to $2.2million) and for individuals (for up to $1.1million).
  • Groundwater allocations are guided by groundwater water balance modelling

Suggested Measures:

  1. Replenishing the aquifers in overexploited areas is essential. Financial and legal incentive should be given to individuals to recharge the common groundwater source.

Example: In Chennai, rooftop rainwater harvesting has been made compulsory for buildings over three stories. The captured water is directed into the ground to recharge the aquifer.

  1. Wastewater Treatment: Treated wastewater can be a safe source for groundwater recharge
  2. Demineralization: Demineralization using RO system can remove all hazardous impurities from drinking water
  3. Implementation of pollution control laws for prevention of future contamination of aquifers
  4. Government should supply quality drinking water to heavily polluted areas.
  5. Comptroller and Auditor General (CAG) of India in its Performance Audit of Water Pollution in India (2011-12) suggested the following measures:

(i) Establish enforceable water quality standards

(ii) Penalties need to be levied for violations of water quality standards,

(iii) Source control of pollutants through sewage and agriculture runoff entering water bodies in projects for conservation and restoration of lakes

  1. Restrict the landowner’s rate of extraction. Overexploitation of groundwater resources should be charged.
  2. Research and Development in areas of water treatment technologies
  3. Public awareness
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