Arsenic in groundwater: Remedies

New arsenal to fight arsenic: sand, garlic

Subhra Priyadarshini & Biplab Das

The humble garlic can reverse toxic effects of arsenic© Subhra Priyadarshini

Two separate papers this fortnight have suggested solutions — one geological and another biochemical — to combat deadly arsenic toxicity in groundwater in the Bengal and Bangladesh regions.

The first paper¹ in Current Science contends that by tapping groundwater from a specific aquifer from the 'orange sand' layer of earth, villagers in the hundreds of affected hamlets could get arsenic-free groundwater.

In the Bengal delta, people tap groundwater from a grey, fine sand layer about 20–50 metres under ground. Community wells made in these localities by the local administration tap water from the deeper grey, fine sand aquifers 60–140 m below ground. This water is laced with high arsenic content resulting in severe health hazards for the villagers.

The researchers suggest that some boreholes that have intersected the 5–10 m thick orange sand layer at a depth of 40–50 m, sandwiched between two high-arsenic grey sand-bearing aquifers, might do the trick. In two worst affected villages of Nadia district in West Bengal, they analyzed water from four test tubewells dug in the orange sand aquifer and found arsenic-free potable water for about one year. "This may be used as a guideline for future tubewells. Geogenic arsenic pollution in the Bengal delta can be eradicated by this foolproof geological method," says Taraknath Pal, the lead researcher.

In the second study² published online in Food and Chemical Toxicology, the researchers suggest that such populations exposed to arsenic can be protected from its toxic effects with the pungent spice garlic. They have shown in animal studies that garlic overcomes the drawback of existing therapeutic agents used to combat arsenic-induced toxicity. "Garlic contains a host of sulfur-bearing organic compounds that easily penetrate through the human cell membrane and bind to arsenic," says lead researcher Keya Chaudhuri. This converts arsenic into a less toxic form that the body can easily pass out with urine.

• References

  1. Pal, T. et al. ‘Orange sand’ – A geological solution for arsenic pollution in Bengal delta. Curr. Sci. 94, 31-33 (2008).
  2. Choudhury, R. et al. In vitro and in vivo reduction of sodium arsenite induced toxicity by aqueous garlic extract. Food Chem. Toxicol. 46, 740-751 (2008). doi:10.1016/j.fct.2007.09.108