Arsenic

2020-02-02

Arsenic is a chemical element with the symbol As, an atomic mass of 74.921 595, and an atomic number of 33. It is in the pnictogens group of the periodic table and its element category is Metalloid. Arsenic has a metallic grey appearance and is primarily used in alloys of lead. Its multiple allotropes come in a variety of colours—including yellow and black—but only the grey form is important to industry. Arsenic is found in many minerals, usually in combination with metals and sulfur, but it can also present as a pure elemental crystal. Arsenic is both an organic and inorganic chemical. It is a Group-A carcinogen and all forms of the element are a serious risk to human health. [1, 2]

Uses [1,2]

Arsenic is primarily used for strengthening alloys of lead and copper for use in car batteries or ammunition. While once a popular component in the production of pesticides, herbicides and insecticides, the use of arsenic is declining due to toxicity of the chemical. Arsenic is also used as an n-type dopant in semi conductive electronic devices. Some species of bacteria use arsenic compounds as respiratory metabolites, and trace elements of the chemical are essential in the diets of rats, hamsters, goats and chickens. There is no known role for arsenic in human metabolism—however, arsenic contamination of groundwater affects millions of people across the globe.


  • Routes of Exposure [3]

  • People can be exposed to arsenic by skin contact, inhaling it, or by consuming contaminated food, water or other drinks.

  • Humans are normally exposed to trace amounts of arsenic in the air, water and foods they consume.
  • Higher levels of arsenic may be found in industrial areas that currently or previously contained arsenic.
  • Drinking water that is associated with high levels of arsenic is known as an area of high exposure.

Health Effects

Arsenic poisoning can be a result of organic or inorganic arsenic, and it affects a range of systems including the skin, nervous, respiratory and cardiovascular systems.

Acute Effects [4]

Severity of symptoms depend on the level and type of exposure. Accute effects are the result of short-term exposure by high concentrations of arsenic.

  • If the arsenic is inhaled, pulmonary oedema, dyspnoea and muscous membrane irritation may occur.
  • If swallowed, arsenic can cause severe vomiting and abdominal pain within the first one to two hours.
  • Cardiovascular effects include vasodilation, cardiac depression and cardiac shock.
  • Symptoms of CNS and PNS effects include: headache, coma, convulsions, cerebral oedema and/or sensory loss.
  • Arsenic poisoning can also result in anaemic, leukopaenia and hepatic toxicity.

Chronic Effects [4]

Arsenic is toxic to multiple body systems. Long-term exposure to the element can cause skin changes (new lesions, redness, swelling, darkening or discolouration and hyperkeratosis—bumps in the skin that resemble warts), and persistent digestive issues, including problems with liver and kidney function. It has also been linked to causing conjunctivitis, loss of appetite, weakness, motor paralysis and bone marrow depression with pancytopaenia. Chronic arsenic exposure has been linked to the development of certain cancers, including that of the kindey, lung, skin and bladder. Long-term symptoms can be present 5 years after exposure. Inorganic arsenic compounds are more toxic than its organic counterparts.

Safety

~h2First Aid Measures [5]

  • Ingestion: If ingested, rinse mouth and DO NOT induce vomiting. Arsenic is fatal if swallowed. Immediately call a doctor or a poison centre.
  • Skin contact: In case of skin or hair contact, remove/take off all contaminated clothing immediately and thoroughly rinse with water. Immediately call a doctor or poision centre.
  • Eye contact: Flush eyes carefully with water for several minutes. Check for and remove contact lenses if easy to do so. Continue rinsing.
  • Inhaled: Take contaminated person to nearest fresh air source and monitor their breathing.
  • General: Never administer anything by mouth to an unconscious, exposed person.

  • Exposure Controls/Personal Protection [5]

  • Engineering controls: Safety showers and emergency eyewash fountains should be accessible in the immediate area of the potential exposure. Ensure there is adequate ventilation. Whenver possible, material should be handled in a laboratory.

  • Personal protection: Safety glasses, protective and dustproof clothing, gloves and a combined gas/dust mask with a B/P3 filter.

Regulation [6]

~h2United States:

</u>Agency

Level

ACGIH(American Conference of Governmental Industrial Hygienists)

10micrograms/m3

NIOSH (NationalInstitute for Occupational Safety and Health)

2micrograms/m3

OSHA(Occupational Safety and Health Administration)

10micrograms/m3

EPA(Environmental Protection Agency)

10 parts perbillion

FDA (Foodand Drug Administration)

0.5-2 partsper million

Australia [4]

Safe Work Australia: Safe Work Australia has set an 8-hour time weighted average (TWA) concentration for arsenic of 0.05mg/m3. However, it should be noted that the TWA values are likely to be higher than the biological standards exposure level for the chemical; therefore, all reasonable steps must be taken to minimise the level of exposure to a level well below the workplace standard.

References

https://en.wikipedia.org/wiki/Arsenic#Exposure

https://wanttoknowit.com/uses-of-arsenic/

https://www.medicinenet.com/arsenic_poisoning/article.htm#what_are_the_symptoms_of_arsenic_poisoning

https://www.safeworkaustralia.gov.au/system/files/documents/2002/health_monitoring_guidance_-_arsenic.pdf

http://www.labchem.com/tools/msds/msds/LC11505.pdf

https://www.atsdr.cdc.gov/csem/csem.asp?csem=1&po=8