What is the Difference Between Organic and Inorganic Arsenic

Arsenic is a naturally occurring chemical element found in the Earth’s crust, known for its toxicity to humans and other organisms. Organic arsenic and inorganic arsenic are two forms of the element arsenic, each with distinct properties and sources. Understanding the difference between organic and inorganic arsenic is crucial for assessing their impact on human health and the environment.

What is the difference between organic and inorganic arsenic? Organic arsenic compounds contain carbon, while inorganic arsenic lacks carbon.

Key Areas Covered

1. What is Organic Arsenic
      – Definition, Features 
2. What is Inorganic Arsenic
      – Definition, Features 
3. Similarities Between Organic and Inorganic Arsenic
      – Outline of Common Features
4. Difference Between Organic and Inorganic Arsenic
      – Comparison of Key Differences
5. FAQ: Organic and Inorganic Arsenic
      – Answers to Frequently Asked Questions

Key Terms

Arsenic, Organic Arsenic, Inorganic Arsenic

Difference Between Organic and Inorganic Arsenic - Comparison Summary

What is Organic Arsenic

Organic arsenic compounds are a subset of arsenic-containing chemicals that incorporate carbon atoms bonded to arsenic. Unlike inorganic arsenic compounds, which are often toxic and pose significant health risks, organic arsenic compounds are generally considered less harmful. Common sources of organic arsenic include seafood, particularly fish and shellfish, where it is naturally present.

Organic Arsenic

Figure 1: Elemental Arsenic

In marine environments, certain microorganisms can convert inorganic arsenic into organic forms through biological processes. These organic arsenic compounds, such as arsenobetaine and arsenocholine, are typically less toxic to humans and are excreted more efficiently from the body. Consequently, the consumption of seafood containing organic arsenic is generally considered safe within recommended dietary guidelines.

However, the safety of organic arsenic compounds is not universal across all forms. Arsenic-containing pesticides, although classified as organic arsenic, can still pose risks to human health. Chronic exposure to these compounds may have adverse effects, and regulations exist to monitor and limit their use in agriculture.

What is Inorganic Arsenic

Inorganic arsenic is a toxic element that naturally occurs in the Earth’s crust. Its presence in groundwater and certain minerals poses significant health risks to humans and animals. Arsenic contamination in drinking water is a global concern, affecting numerous regions and communities. The two primary forms of inorganic arsenic, arsenite and arsenate exhibit distinct toxicological properties.

Chronic exposure to inorganic arsenic is associated with various health issues, including skin lesions, cardiovascular diseases, and an increased risk of certain cancers, particularly lung, bladder, and skin cancers. The mechanism of arsenic toxicity involves interference with cellular processes, inhibition of enzymes, and generation of reactive oxygen species that damage cellular structures.

Inorganic Arsenic

Figure 2: Arsenite

Developing nations often face higher incidences of inorganic arsenic contamination due to inadequate water management and limited resources for water purification. Industrial activities, such as mining and smelting, can also contribute to elevated arsenic levels in soil and water.

Efforts to mitigate arsenic exposure include the implementation of water treatment technologies, such as coagulation, filtration, and adsorption, to remove arsenic from contaminated water sources.

Similarities Between Organic and Inorganic Arsenic

  1. Organic and inorganic arsenic contain arsenic as a chemical element.
  2. Both forms can be found naturally in the environment and can be present in water, soil, and food.
  3. Both organic and inorganic arsenic compounds can pose health risks if consumed in high concentrations.

Difference Between Organic and Inorganic Arsenic


Organic arsenic refers to arsenic compounds containing carbon, often found in living organisms and considered less toxic, while inorganic arsenic refers to arsenic compounds lacking carbon, typically found in soil and water sources and known for their higher toxicity to humans and other organisms.


Organic arsenic compounds contain carbon atoms bonded to arsenic atoms, while inorganic arsenic compounds do not contain carbon-arsenic bonds.


Inorganic arsenic compounds are generally more toxic than organic arsenic compounds.

Found in

Inorganic arsenic compounds are commonly found in groundwater, industrial processes, and some pesticides, while organic arsenic compounds are primarily found in marine organisms like fish and shellfish.


In summary, the difference between organic and inorganic arsenic lies in their chemical makeup and toxicity levels. Organic arsenic, found in seafood, contains carbon-arsenic bonds and is generally less harmful. In contrast, inorganic arsenic lacks carbon, is more toxic, and is often found in groundwater and industrial processes, posing health risks like cancer. Understanding these differences is crucial for managing and mitigating arsenic exposure effectively. Monitoring and regulation are essential to protect public health and the environment from arsenic-related hazards.

FAQ: Organic and Inorganic Arsenic

1. What are the 3 types of arsenic?

Arsenic is a naturally occurring metalloid element that comes in three major forms: inorganic, organic, and arsine gas (-3 oxidative state), as well as three major valence states: arsenic element (0), arsenite (trivalent +3) and arsenate (pentavalent +5).

2. What are the organic forms of arsenic?

Common organic arsenic compounds include arsanilic acid, methylarsonic acid, dimethylarsinic acid (cacodylic acid), and arsenobetaine.

3. What are the disadvantages of inorganic arsenic?

The disadvantages of inorganic arsenic include its higher toxicity compared to organic arsenic, posing significant health risks such as cancer and other serious illnesses. Inorganic arsenic exposure can occur through contaminated groundwater, industrial processes, and certain foods, leading to acute and chronic health effects.

4. What does organic arsenic look like?

Most inorganic and organic arsenic compounds are white or colorless powders that do not evaporate. They have no smell, and most have no special taste.

5. Which form of arsenic is more toxic?

In general, inorganic arsenic is considered to be more toxic compared to organic arsenic. Inorganic arsenic is typically more readily absorbed and metabolized by the body. Inorganic arsenic compounds have been associated with a higher risk of adverse health effects, including various types of cancer (such as skin, lung, bladder, and liver cancer), cardiovascular diseases, neurological disorders, and reproductive issues.


1. “Organoarsenic Chemistry.” Wikipedia. Wikipedia Foundation.

Image Courtesy:

1. “Arsen 1a” By Arsen_1.jpg: Original uploader was Tomihahndorf at de.Wikipedia derivative work: Materialscientist (talk) – Arsen_1.jpg (CC BY-SA 3.0) via Commons Wikimedia
2. “Arsenate ion” By Ed (Edgar181) – Own work (Public Domain) via Commons Wikimedia

About the Author: Hasini A

Hasini is a graduate of Applied Science with a strong background in forestry, environmental science, chemistry, and management science. She is an amateur photographer with a keen interest in exploring the wonders of nature and science.

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