Arsenic Contamination: Forms, Uses, Threats, Arsenicosis, Arsenic Levels, Biomarkers (Download PDF)

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Arsenic

  • A chemical element with the symbol As and atomic number 33 atomic mass of 74.92.
  • It is a metalloid.
  • Occurs in many minerals usually in combination with sulfur and metals.
  • Toxic to almost all life forms.
  • Naturally present at high levels in the groundwater or a natural component of the earth՚s crust.
  • It is more toxic in its inorganic form.

Dietary Sources of Arsenic

  • Dairy products and cereals
  • Meat
  • Fish
  • People smoking tobacco can also be exposed to the natural inorganic arsenic content of tobacco.
  • Millions of people around the world are exposed to arsenic at concentrations much higher than the guideline value (100 μg/L or greater) .

Forms of Arsenic

  • Crystalline, powder, amorphous or vitreous forms.
  • Usually occurs in trace quantities in all rocks, soil, water and air.
  • Arsenite [As (III) ] is the most toxic form of arsenic and causes and causes acute toxicity.
  • Arsenite [As (v) ] can cause chronic toxicity.
  • Methylated forms of arsenic [MMA (V) , DMA (V) ] .

Use of Arsenics

  • As an alloying agent.
  • Processing of glass, pigments, textiles, paper, metal adhesives, wood preservatives and ammunition.
  • Hide tanning process.
  • To a limited extent in:
  • Pesticides
  • Feed additives and pharmaceuticals.

Threats to Public Health from Arsenic

  • Contaminated water used for drinking, food preparation and irrigation of food crops.
  • Nerve damage.
  • Negative impacts on cognitive development.
  • Increased deaths in young adults.
  • Adverse pregnancy outcomes and infant mortality.
  • Muscle cramping and death.
  • Diabetes

Skin Damage

  • Hyperkeratosis or scaling skin
  • Pigment changes

Cancer Risks

  • Lung
  • Bladder
  • Kidney
  • Liver

Cardiovascular System

  • Coronary heart disease
  • Hypertension
  • Heart attack

Respiratory System

  • Pulmonary tuberculosis
  • Bronchiectasis

Arsenicosis

  • Accumulation of large amounts of arsenic in the body.
  • Diverse health effects.
  • Inhibition of essential enzymes.
  • Death due to multisystem organ failure.
  • It is not contagious i.e. it doesn՚t spread from one person or organism to another.
Organic Arsenic V/S Inorganic Arsenic
Organic ArsenicInorganic Arsenic
Less ToxicHighly Toxic
Covalently bonded arsenic atoms.Bonded to non-carbon chemical elements. It may also be pure and metallic form of arsenic.
Arsenic is bound to carbon atoms.Not bound to carbon atoms.
Arsenobetaine and arsenocholine are the two forms.Arsenite and arsenate are the two forms.

Arsenic Levels

  • WHO guideline value for drinking water is 10 μg/L (Provisional because of practical difficulties in arsenic removal from drinking water)
  • In India the considered accepted level for arsenic in drinking water is 50 μg/L.
  • In United States the prescribed value for arsenic in drinking water is 10 μg/L.
  • In Africa the arsenic level for surface water is ranged up to 10,000 μg/L and for groundwater range between 0.02 and 1760 μ/g L.
Arsenic Affected Countries
Arsenic Affected Indian States

Biomarkers of Arsenic (Person Consuming Arsenic Contaminated Water)

  • Hair
  • Nails
  • Urine
  • Skin scales

Toxicity of Arsenic Species to Freshwater Organisms

Toxicity of Arsenic Species

Prevention and Control

  • A safe water supply for drinking, food preparation and irrigation of food crops.
  • Substitute high-arsenic sources, such as groundwater, with low-arsenic, microbiologically safe sources such as rain water and treated surface water.
  • One can use low-arsenic water for drinking, cooking and irrigation purposes.
  • High-arsenic water can be used for other purposes such as bathing and washing clothes.
  • Testing water for arsenic levels.
  • Painting tube wells or hand pumps different colours.
  • Blending low-arsenic water with higher-arsenic water so as to achieve an acceptable arsenic concentration level.
  • Install arsenic removal systems - either centralized or domestic.
  • Appropriate disposal of the removed arsenic.

Technologies for arsenic removal include:

  • Oxidation
  • Coagulation-precipitation
  • Absorption
  • Ion exchange
  • Membrane techniques

Education and community level engagements:

  • Risks of High arsenic exposure
  • Sources of arsenic exposure
  • Monitoring the High-risk populations for early signs of arsenic poisoning usually skin problems.

WHO Response

  • Setting guideline values, reviewing evidence and providing risk management recommendations have been included under who՚s work to reduce arsenic exposure.
  • Efforts should be made to keep concentrations as low as reasonably possible and below the guideline value when resources are available.
  • The public health priority should be to reduce exposure to millions of people around the world are exposed to arsenic at higher concentrations.
  • Global targets on drinking water are being monitored by the WHO/UNICEF Joint Monitoring Programme for Water Supply, Sanitation and Hygiene.
  • Tracking the population accessing drinking water (free of faecal contamination and priority chemical contaminants including arsenic) under the new 2030 Agenda for Sustainable Development.

- Published/Last Modified on: April 8, 2020

Science/Technology, Environment/Ecology

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