Death by slow poisoning

Death by slow poisoning

News:

1.An estimated 10 million people in nine districts of West Bengal drink arsenic-laden groundwater.

Important Facts:

2.Today, around 10 million people in nine districts in West Bengal and 40 million in Bangladesh drink arsenic laden ground water.

3.The source of the arsenic contamination can be traced back to the following geological processes:

• Around 18,000 and 6,000 years ago, small Himalayan rock particles, coated with iron oxide, entered the Ganga river delta.
• On the way, these particles absorbed the tiny amounts of arsenic in the river water, like a sponge soaking liquid.
• These particles were then deposited in layers of sediment, over thousands of years, in what is now West Bengal and Bangladesh.
• Decaying organic matter or peat acted on these rocks. These organic matter used up the oxygen from the iron oxide present in the rocks for their own metabolism. In the process,
• Around 18,000 and 6,000 years ago, small Himalayan rock particles, coated with iron oxide, entered the Ganga river delta.
• On the way, these particles absorbed the tiny amounts of arsenic in the river water, like a sponge soaking liquid.
• These particles were then deposited in layers of sediment, over thousands of years, in what is now West Bengal and Bangladesh.
• Decaying organic matter or peat acted on these rocks. These organic matter used up the oxygen from the iron oxide present in the rocks for their own metabolism. In the process, iron and arsenic was set free.
• This increased the concentration of both iron and arsenic in the groundwater.
• In 1970’s tube wells were dug out due to increased surface water contamination.This unleashed the underground arsenic.4.Shallow tube wells, less than 150 meters deep, are the worst affected, because they contain arsenic-rich sediments from the Holocene era, when the arsenic arrived in the delta.5.Can Deep aquifers be the solutions?
  • Deep aquifers, more than 150 meters underground, are unaffected because they tap into the older Pleistocene sediments. Bangladesh has been using deep tubewells for accessing safe water.
  • But even deep aquifers can become contaminated with the overuse of groundwater as it disturbs the clay separating the deep and shallow aquifers.For example, North 24 Parganas, deep tube wells which were uncontaminated initially saw arsenic levels rise in about five years.
  • Thus the initial strategy of the government of digging deeper wells to replace the shallow ones was not feasible.

  6.Effect on people:

  • On the Skin:

   (i)The most visible symptom in early years is a classic blotchy pattern on the skin, a condition called raindrop pigmentation.

  (ii)Next they develop hyperkeratosis — dark crusts on their palms and soles.

  (iii)Skin can turn cancerous. E.g., Bowen’s Carcinoma.

  • It can also destroy the kidneys and liver tissue, cause conjunctivitis and affect the lungs causing arsenicosis.
  • It is a silent killer, it can take years for keratosis to show in adults and even longer in children.
  • Arsenic contaminated children have lower IQ.
  • Social stigma attached to it affects the livelihood of the person.

  7.This problem of arsenic contamination has been compared with the Chernobyl disaster.

  8.Steps taken by the Government and NGOs and reasons for its failure:

  • A water treatment plant was installed in Madhusudhankati by thefarmer’s cooperative society with the help of Sulabh International.

   Reason for failure: despite the availability of safe water, people drank contaminated water.

  • The government appointed committees in 1983,1988,1992 and 1993 to look into the problem of arsenic contamination but no proper follow up action was taken.
  • By 2007, the government tested over 1 lakh wells for contamination.

  Reason for failure: The contaminated wells were not marked making the whole exercise futile.

  • UNICEF and other NGOs focus was on public outreach. They held door-to-door campaigns, street plays, distributed flyers.

    Reason for failure: It could not cover enough areas to make a significant change.

  • The campaign needed dedicated communication experts which the Government did not have.

A household filter was developed by SOES with two components:

• •     (i)A tablet made of iron salt, an oxidizer and activated charcoal. The tablet reacts with arsenic and turns it into a filtrable floc.    (ii)A fly ash filter to filter the floc. Reason for failure:

    People did not know how to use them.

    People would use multiple tablets instead of just one.

    Tablets would be exposed to sunlight and dried out by mistake

    Toxic arsenic sludge was disposed of unsafely releasing back into the ground.

    • Treatment plants have been installed in many locations:

    Reasons for failure: Arsenic removal technologies are still emerging.

    Plants are operating at low efficiencies because of maintenance issues.

    9.Steps to be taken: Challenges:

  •  (i)Technical challenges in laying such long pipelines.(ii)Total estimated cost is Rs 1 lakh crore.10.Efforts currently underway
    • Short term strategy: Provide Hooghly water to half the contaminated villages and community arsenic treatment plants for the other half.
    • Commissioning 170 community arsenic treatment plants.