A recent study published in Current Opinion in Environmental Science & Health, authored by Neog, Nikita et al. (2024), titled ‘Arsenic Contamination in the Groundwater of Northeastern India: Critical Understandings on Geotectonic Controls and the Need for Intervention,’ sheds light on the concerning levels of arsenic contamination in the groundwater of Northeastern India, stemming from the Himalayan Mountain region. States such as Assam, Manipur, Arunachal Pradesh, Nagaland, and Tripura are particularly affected, with arsenic concentrations surpassing the WHO’s acceptable limit of 10 µg L-1 (Micrograms per Liter).
According to a WHO report from 2011, the economic strain resulting from arsenic toxicity in Northeastern India is anticipated to manifest soon. While research in Assam has provided some insights, there remains a significant gap in understanding arsenic prevalence in other Northeastern states, highlighting the need for further comprehensive studies.
Recognizing the severity of the issue, the National Green Tribunal has issued notices to 24 states and four Union Territories, including Assam, Manipur, Tripura, Meghalaya and Nagaland, emphasizing the urgency for “urgent preventive and protective steps” against arsenic and fluoride contamination in groundwater.
In Nagaland, districts such as Mokokchung, Mon, Wokha, and Zunheboto exhibit arsenic concentrations ranging from 50 to 278 µg L-1. Geological composition, including tertiary-age semi-consolidated deposits and formations like Tipam, Barail, and Disang, contributes to arsenic presence. Detailed hydrogeochemical studies are crucial to identifying specific geological formations contributing to arsenic contamination.
The Northeastern Region’s unique geospatial and geoscientific setup, with the Indo–Burman orogenic belt traversing several states, plays a pivotal role in arsenic contamination. Plate tectonics, ophiolitic rocks, red radiolarite, and pelagic sediments contribute to arsenic presence, especially in floodplains, as per the study.
A recent study by Nikita Neog et al. (2024) investigated arsenic enrichment in Northeast India’s aquifer system, highlighting three governing deductions. These include the facilitation of leaching-driven arsenic release from rocks in the tropical environment, the role of plate tectonics in sedimentary arsenic content, and microbial-mediated weathering contributing to arsenic enrichment.
As arsenic contamination continues to pose a threat to public health and the environment in Northeastern India, urgent intervention and collaborative efforts are imperative to mitigate its adverse effects and ensure the safety of groundwater sources.