Arsenic contamination of groundwater is an ongoing crisis affecting millions of people and exacerbating long-overlooked public health challenges.
According to a report from the Ministry of Water Resources presented in the Rajya Sabha in December 2024, arsenic contamination level exceeds the World Health Organization prescribed limit in 230 districts across India, including 21 districts in Assam.
Arsenic, a naturally occurring but highly toxic element, poses long-term health risks such as skin lesions, cancers, and cardiovascular diseases.
While the Jal Jeevan Mission has made significant progress in expanding access to water, the focus on water quality remains inadequate. Although the mission is essential for improving water access in remote areas, it is insufficient if the water provided is contaminated.
The mission must incorporate mechanisms to ensure that the water supplied is free from geogenic contaminants like arsenic and fluoride, another prevalent contaminant in Assam’s groundwater.
Without this focus on water quality, there is a risk of unintentionally distributing arsenic-laden water through the vast rural pipelines in Assam and other arsenic-contaminated regions of India.
Geopolitical risks accelerate the growing importance of groundwater in Assam. In addition to local environmental and climate challenges and the absence of a major Water Treaty between India and China, Assam faces external geopolitical risks that further challenge its water security.
China’s plans to construct hydropower plants upstream of the Brahmaputra River, with significant control over the river’s flow, pose a growing threat to Assam’s water resources.
The Brahmaputra, which flows through Assam, is vulnerable to disruption due to its steep gradient in Tibet, which is suitable for hydropower plants and, hence, China’s proposed diversion projects.
These geopolitical dynamics accentuate the critical need to rely on groundwater as a stable, year-round water supply.
With the increasing unpredictability of surface water availability owing to upstream hydrological interventions, Assam must prioritize sustainable groundwater management practices.
However, as evidenced by the widespread arsenic contamination, groundwater quality is not guaranteed, highlighting the urgent need for localized and decentralized treatment solutions.
Before prescribing treatments, the extent of contamination must be examined under current and future climate change scenarios. For example, it is essential to go beyond simple concentration measurements to understand the scope of arsenic contamination.
Arsenic speciation—whether it is in the toxic arsenite form or the less harmful arsenate form—determines how arsenic behaves in groundwater and its associated risks.
Assam’s vulnerable geography, characterized by frequent flooding and the impacts of climate change, further complicates the issue.
Much research, including my own work, shows that arsenic distribution in groundwater is influenced by environmental factors such as soil mineralogy, organic content, and conditions at the soil-water interface.
These factors can vary significantly across regions in Assam, especially during floods, leading to arsenic speciation fluctuations.
Thus, simply quantifying arsenic concentrations is insufficient. We must focus on understanding its chemical form in groundwater to develop more effective treatment methods.
For instance, highly toxic and mobile arsenite requires different treatment approaches than arsenate. This distinction is crucial for designing targeted solutions that ensure the safety of drinking and irrigation water.
Given the complexity of arsenic contamination in Assam, centralized treatment solutions may not be sufficient. Instead, decentralized, community-based arsenic removal technologies should be prioritized.
These systems—such as zero-valent iron filters and membrane-based technologies—can be tailored to the specific water bio-geo-chemistry and arsenic levels in each community.
Such localized solutions can offer a more sustainable, cost-effective approach to ensuring safe water access in rural areas, especially during flooding when water quality fluctuates.
Decentralized systems also empower communities to take ownership of water quality management, which is crucial for long-term success. Regular monitoring, community training, and local participation in water management can ensure that these systems remain effective. The Jal Jeevan Mission is yet to implement such initiatives on a broader scale.
To effectively address arsenic contamination in Assam, which can also be applied to other regions of the country, the following measures should be implemented: 1. Routine Testing for Arsenic Concentration and Speciation: Monitoring arsenic speciation (arsenite vs. arsenate) is essential to determine the best treatment methods. Localized testing and monitoring should be implemented to identify areas with the highest risks.
2. Promote Decentralized Treatment Technologies: Community-level arsenic removal technologies should be promoted, especially in rural and flood-prone areas. These should be tailored to local water chemistry and arsenic concentrations.
3. Government and Community Collaboration: Policymakers must collaborate with local communities to implement water quality solutions that are sustainable and culturally appropriate. Community awareness and participation are crucial for the success of any water management system if we are serious about water justice.
4. Integrating Geopolitical Risks into Water Policy: The potential impact of upstream interventions on the Brahmaputra’s flow should be factored into long-term water management policies. Groundwater management can safeguard against the uncertainty surrounding surface water resources.
The arsenic contamination crisis in Assam requires a comprehensive, multi-faceted approach that balances both access and quality. While the Jal Jeevan Mission’s focus on providing piped water is a critical step, it must be complemented by efforts to ensure the safety of that water.
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By integrating arsenic speciation into water management practices, promoting decentralized treatment technologies, and addressing both local and external risks, Assam can ensure a sustainable, safe, and equitable water future for its people.
