People Immune to Poisonous Levels of Arsenic in Water

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People Immune to Poisonous Levels of Arsenic in Water

Researchers have found that people living in the Atacama Desert have evolved over the period of 7000 years to not be influenced by extremely elevated arsenic levels in their water supply.

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The Atacama Desert (Alamy; GettyImages/National Geographic )

Arsenic,   As, is a chemical element that is found in many minerals, often in combination with sulfur and metals, but also as a crystal.

It is odorless and tasteless. It can enter drinking water supplies from natural deposits in the earth or from agricultural and industrial practices. 

Effect of Arsenic on human health: Long-term exposure to inorganic arsenic, mainly through drinking of contaminated water, eating of food prepared with this water and eating food irrigated with arsenic-rich water, can lead to chronic arsenic poisoning.

Skin lesions and skin cancer are the most characteristic effects.   Non-cancer effects of arsenic can include:

  1. Thickening and discoloration of the skin,
  2. Stomach pain,
  3. Nausea,
  4. Vomiting,
  5. Diarrhea,
  6. Numbness in hands and feet,
  7. Partial paralysis, and
  8. Blindness.

Permissible level of  Arsenic in drinking water:  It should be 10 µg As/ l according to WHO and EPA
standards.

Paper published in the 'American Journal of Physical Anthropology' explains the genetic study which tried to explain why people living in the Atacama Desert in Chile are not influenced by extremely elevated arsenic levels in their drinking water.

Arsenic-contaminated water is their only drinking source and it contains 1 mg/l of arsenic, which is a 100 time more than the maximum acceptable level.

It is assumed their ancestors have had severe health problems due to arsenic and due to survival of the fittest, the population remained alive and evolved to tolerate high arsenic levels.

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Local women in San Antonio de los Cobres in the Andes carry a genetic variant that gives them greater tolerance of the poison arsenic by helping them to metabolise the element more efficiently; Photo Source Guigue

150 of locals were genetically tested and it was found they had a specific enzyme which was already known to affect people’s ability to tolerate arsenic.

However, only a certain percentage of people had this enzyme. Therefore, this is not the only parameter which affects their tolerance.

It is yet to be established what the other factors are by sequencing the whole chromosomal region.


Read about Arsenic removal here.

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