Render arsenic-laden water safe with science

Arsenic poisoning occurs when ingested at high levels and is similar to poisoning by heavy metals like lead or mercury.
Indian Institute of Science (IISC) in Bengaluru. Representational image
Indian Institute of Science (IISC) in Bengaluru. Representational imageFile photo| EPS

The Indian Institute of Science in Bengaluru has developed a three-step remediation process to render groundwater-based arsenic harmless. Arsenic has severe health implications, but the latest development can effectively reduce its toxicity to harmless levels and ensure people’s safety. According to a 2023 report from the Central Ground Water Board on shallow aquifers, 113 districts in 21 states of the country have groundwater with arsenic levels well above 0.01 mg per litre considered tolerable by the World Health Organization.

Arsenic is a semi-metal whose compounds are used in rat poison. But its almost ubiquitous presence in groundwater exposes unsuspecting people to its adverse effects. Its prolonged consumption is known to cause severe health issues such as lung, skin, kidney and bladder cancers; coronary diseases; bronchiectasis (a chronic lung condition featuring infection-induced widening and thickening of bronchi or airways); hyperkeratosis (increased thickness of the stratum corneum, the outer layer of the skin); and arsenicosis, which involves a chronic condition arising from the ingestion of arsenic for six months featuring skin lesions that may affect internal organs.

In many cases, only the disease is visible and diagnosed, not the cause, which is arsenic. The problem is more acute in the lowlands of West Bengal, Bihar and Uttar Pradesh, particularly in the Ganga-Meghna-Brahmaputra region where around 60 lakh people remain exposed to arsenic concentrations in groundwater above 50 parts per million.

The three-step remediation method by IISc’s Centre for Sustainable Technologies involves an adsorbent bed grabbing toxic inorganic arsenic through electrostatic forces and complex formation between arsenic and the adsorbent; the alkaline wash solution of sodium hydroxide and arsenic in water being taken to a membrane system to separate the two; and toxic inorganic arsenic converted to low-toxicity organic arsenic by adding methyl molecules using microbes in cow dung.

Arsenic poisoning occurs when ingested at high levels and is similar to poisoning by heavy metals like lead or mercury. The ill-effects of long-term exposure to arsenic in groundwater are prevalent across India. Inner Voice Foundation, which works to address the issue, says about 10 lakh people have died from arsenic in drinking water over the last three decades. It is time the health authorities at the Centre and in the states fall back on reliable technologies to address the problem and save lives.

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