Context: 

A recent peer reviewed study published in the journal JAMA Network Open suggests that even low levels of arsenic consumption may impact cognitive function in children, adolescents, and young adults.

About the Study:

• The research study is part of a bigger investigation into how a range of environmental and biological factors affect neurological and cognitive development in young people.
• For their research, the scientists linked urine samples (to estimate arsenic exposure) performance in a battery of computerised tests (that evaluate cognitive function) and brain images (that picturise various regions of the brain).

Findings of the Study:

• Those exposed to arsenic had reduced grey matter (brain tissue that is vital to cognitive functions) and weaker connections within key regions of the brain that enable concentration, switching between tasks, and temporary storage of information.
• Chronic exposure to arsenic could be creating a silent pandemic affecting large portions of the global population.

Arsenic and Human Health:

• Long-term exposure to arsenic in drinking-water is causally related to increased risks of cancer in the skin, lungs, bladder and kidney, as well as other skin changes such as hyperkeratosis and pigmentation changes. 
• Soluble inorganic arsenic is acutely toxic, and ingestion of large doses leads to gastrointestinal symptoms, disturbances of cardiovascular and nervous system functions, and eventually death. 
• In survivors, bone marrow depression, haemolysis, hepatomegaly, melanosis, polyneuropathy and encephalopathy may be observed.

About Arsenic:

• Arsenic is a natural component of the earth’s crust and is widely distributed throughout the environment in the air, water and land. It is highly toxic in its inorganic form.
• Sources of Arsenic:

• • Arsenic is emitted into the atmosphere by high-temperature processes such as coal-fired power plants, burning vegetation and volcanism.  
  • In water, particularly groundwater, where there are sulphide mineral deposits and sedimentary deposits deriving from volcanic rocks, the concentrations can be significantly elevated.  
  • Natural low-temperature biomethylation and reduction to arsines also releases arsenic into the atmosphere.
• Drinking-water and food:
  • Exposure to arsenic in India is strongly linked to food intake, indicating that inorganic and organic arsenic in foods is a significant contributor to overall arsenic exposure.
  • West Bengal, Jharkhand, Bihar, Uttar Pradesh, Assam, and Manipur are regions with high background arsenic levels.
  • Rice consumption, particularly in south India (Rishi Valley and Bangalore), is most commonly correlated with arsenic intake.

Government Efforts to Address Arsenic Contamination: Strategies employed by Central and State governments in Bihar and West Bengal

• Promotion of piped water access over groundwater extraction
• Installation of arsenic removal plants
• Focus on deeper aquifers for groundwater extraction

News Source: The Hindu