Difference Between Organic Arsenic and Inorganic Arsenic (With Table)

Arsenic or As the 33rd element of the chemical periodic table is an element that belongs to the periodic table’s VA group. It is categorized as a metalloid because its physical and chemical characteristics are midway between nonmetals and metals. The relative atomic mass of this element is 74.92. Arsenic may be found in a variety of oxidation states, including –3, 0, +3, and +5. It comes in three allotropic varieties: yellow, black, and grey.

And this article states the chemical and physical differences between organic and inorganic arsenic along with their industrial usages and chemical occurrence.

Organic Arsenic vs Inorganic arsenic

The difference between organic arsenic and inorganic arsenic is that a single atom is linked to carbon in an “organic” arsenic complex, which might be part of a sugar molecule like ribose. This “organic” type has a more complex structure, yet it is completely safe. In contrast, “inorganic” arsenic compounds, such as arsenic trioxide, do not include carbon and are typically simple molecules. These chemicals are extremely dangerous and not for personal usage because of industrial toxicity.

Organic arsenic is the arsenic that occurs naturally in plants and animals or in-ground resources as a dissolved component as part of organic compounds. Some examples of organic arsenic occurring naturally in plants are Arsenobetaine, Cacodylic acid, Arsanilic acid, etc. Seafood is the most common source of arsenic in people’s diets. Organic arsenic levels are known to be high in shellfish, crabs, and seaweed. Organic arsenic has low toxicity when compared to arsenic’s inorganic form.

When considering inorganic arsenic, it is much more toxic and is found naturally as well. Water, soils, and some terrestrial foods, such as rice, contain inorganic arsenic. Inorganic arsenic makes up between 25 and 100 percent of arsenic in land-based foods in various parts of the world. Inorganic arsenic has significant toxicity. Inorganic arsenic for millennia has been manufactured and utilized economically. Pharmaceuticals, agricultural compounds, semiconductors, and glass-making as well as other mining purposes.

Comparison Table Between Organic Arsenic and Inorganic Arsenic

Parameters of ComparisonOrganic ArsenicInorganic Arsenic
Found inOrganic arsenic is arsenic that occurs naturally in plants and animals as part of organic compounds. Its atom is attached to a carbon or carbon-based functional group.Arsenic, occurring in nature in inorganic substances is known as inorganic arsenic. It has a simpler form than the organic one.
UsesOrganic arsenic isn’t as raw and useful as the inorganic one. It occurs naturally in plants and also plays an important role in salt and carbon balance throughout the ecosystem.Pesticides and paint pigments include inorganic forms of arsenic. They were also used to cure a range of illnesses and as wood preservatives.
ToxicityOrganic arsenic has a low toxicity concentration. Organic arsenic is eliminated in humans after a few days of intake and causes no damage to the body or any chemical processes in the body.The toxicity of inorganic arsenic is high and can cause fatal diseases or side effects if consumed directly.
Examplesmethylarsonic acid, arsenobetaine, methylarsonic acid, etc.arsenic trioxide, arsenic pentoxide, lead arsenate, sodium arsenite, etc.
Effects on humanDoes Not cause any adverse or worsening effect on the human body.Can cause cancer of the lungs, skin, bladder, or skin. Can be life-taking if consumed or used beyond the limits.

What is Organic Arsenic?

Arsenic (atomic number 33; relative atomic mass 74.92) is a metalloid or semimetal with chemical and physical characteristics that fall somewhere between a metal and a nonmetal. Arsanilic acid, methylarsonic acid, dimethylarsinic acid (cacodylic acid), and arsenobetaine are some of the most common organic arsenic compounds.

Although it has no direct usage, unlike inorganic arsenic which is toxic yet serves as a cure for many diseases if used correctly and in a prescribed manner. Organic arsenic works at ground level as the skeletal compound in maintaining the chemical balances and life processes in living beings. A little topple in their amount in nature can be reflected by an imbalance in the ecosystem and can eventually cause a pandora’s box of events, that’s how important the basic yet non-lethal organic arsenic is important. It occurs in various chemical forms like methylarsonic acid, arsenobetaine, methylarsonic acid, etc.

In organic arsenic, a significant factor is that it has a carbon or carbon compound attached to its structure and can be a chained sugar compound like sucrose and ribose sugar. The structure of organic arsenic is quite complex when compared to inorganic arsenic. Although the structure is complex and sometimes helical, it is completely harmless for humans. The basic concentration of organic arsenic is most commonly found in sea fishes and crustaceans.

What is Inorganic Arsenic?

Water, soils, and some land foods, such as rice, contain inorganic arsenic. Inorganic arsenic makes up 25 and 100 percent of arsenic in grassland foods in various corners of the world. It is also an important component because of its industrial applications and availability. The inorganic arsenic is found usually in dissolved form and has to be extracted chemically to use it multi-purposively.

Pesticides and paint pigments include inorganic forms of arsenic. They were also used to cure a range of illnesses and as wood preservatives. Two separate lines of population research, defined by the medium of arsenic exposure, provide epidemiological information on arsenic and cancer risk. Inhalation of inorganic arsenic has been linked to cancer in studies. These studies cover mostly working populations who breathed arsenic and other substances polluted air.

Inorganic arsenic is highly poisonous to humans and must not be consumed. It can cause lung, skin, bladder, liver, kidney, and other organ cancers, as well as harm to the stomach, intestines, nerves, skin, and other tissues. Direct skin contact can cause irritation, edema, and redness. Low amounts of exposure can cause abnormal heart rhythms, blood vessel damage, and a decrease in red and white blood cell production.

Main Differences Between Organic Arsenic and Inorganic Arsenic

  1. Organic arsenic is not toxic for humans but inorganic arsenic is very toxic for humans.
  2. Organic arsenic has a complex structure whereas inorganic arsenic has a simpler structure.
  3. Organic arsenic cannot cause cancer whereas inorganic arsenic can cause blood and skin cancer.
  4. Examples of organic arsenic compounds are methylarsonic acid, arsenobetaine whereas examples of inorganic arsenic arsenic trioxide, arsenic pentoxide.
  5. Organic arsenic cannot be used for industrial purposes whereas inorganic arsenic can be used for industrial purposes after extraction.

Conclusion

Arsenic is an essential element in the environment. Let it be organic or inorganic, both the forms have their requisite purposes. Although inorganic arsenic is very toxic and cannot be directly used for consumption or usage but can be useful if used by chemical engineers. 

Seafood is the most common source of arsenic in people’s diets. Organic arsenic levels are known to be high in shellfish, crabs, and seaweed. Water, soils, and some terrestrial foods contain inorganic arsenic.

Arsenic is a poisonous element, however, its toxicity varies depending on its molecular shape and oxidation state, with organic arsenic being less poisonous than inorganic arsenic.

References

  1. https://www.ncbi.nlm.nih.gov/books/NBK304380/
  2. https://www.epa.gov/sites/default/files/2016-09/documents/arsenic-compounds.pdf
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