Arsenic occurs naturally in several forms, usually as a compound mixed with other elements. It is a poisonous substance with varying toxicities, depending on the type of compound it is. It is most toxic in its inorganic form mixed with chlorine, oxygen, or sulfur, and least toxic in its organic forms. Solid arsenic tarnishes the air and comes as a brittle silver-gray semi-metal.
What Is Arsenic Used for?
1. Materials Preservation
Chromated copper arsenate, which is a type of organic arsenic, is primarily used as an agent to preserve and extend the life of pressure-treated wood. It is used by injecting the arsenic into the wood's cellular structure. Because of its poisonous properties, it works well to kill any bacteria, fungi, and insects that can eat away at the wood, causing it to deteriorate more quickly. However, the use of arsenic on consumer products has been banned in many countries because of its high toxicity levels. Similarly, arsenic is also being used in the leather industry as a way of preserving tanned leather.
2. Electronics and Engineering
One example of "what is arsenic used for in engineering" is as a doping agent. Doping is a process in which arsenic or any other impurity is added to a semiconductor, such as a transistor or other solid state devices. Doing this causes the semiconductor to increase its conductive properties. Other engineering uses for arsenic include hardening lead, reducing friction in ball bearings, and manufacturing optical materials made of germanium, arsenic, and selenium. Previously, it was also used in its compound form mixed with indium and gallium as one of the materials for short wave infrared technology.
3. Chemical Manufacturing
Arsenic is also an ingredient in the production of fireworks and is used in order to make the colors more vibrant. In lasers, gallium arsenide is used as a way of releasing the laser light.
4. Old Medicine
Surprisingly, doctors in the 18th and 19th centuries found a use for arsenic compounds. It was used to treat syphilis before penicillin was discovered, and it was also an ingredient in many medicinal solutions. For example, Fowler's solution was made of 1% potassium arsenite, Donovan's solution was made of arsenic trioxide, and de Valagin's solution was made of arsenic trichloride. All of these solutions were used to treat several diseases.
5. Agriculture
Another popular use for arsenic is as a weed killer. It is often sprayed onto fields and crops from an elevated height, such as from a small aircraft, in order to destroy infestations. Similarly, as an insecticide, it is most commonly used as a solution to termite infestations. However, one major drawback to arsenic is its toxicity and poisonous property, making it unpopular, especially among those who are very concerned about the organic trend. The rise of products that are grown organically has made agricultural applications a poor choice when it comes to "what is arsenic used for in agriculture". Because of this, the demand for arsenic in farms has decreased very substantially.
What Can Arsenic Do to Our Health?
Arsenic is a naturally-occurring substance, so it can be found in low quantities in air, water, and soil. Because it is so readily available in nature, it is inevitable for plants to absorb them as they grow. Unfortunately, this means that low levels of arsenic can essentially make their way into our food, down our throats, and into our bodies.
Some consequences of long-term exposure to arsenic, even in small doses, include alteration in the way bodily cells behave and interact with each other, ultimately reducing their function and affecting their performance. Some studies have suggested that it can actually be one of the factors for the development of cancer, vascular diseases, diabetes, and lung diseases.
Meanwhile, the negative effects of long-term exposure to larger doses of arsenic include increased risk for developing heart diseases, as well as cancers of the skin, lungs, and bladder. Fortunately, arsenic is not known to remain in the body and cause buildup. Any quantity of arsenic that makes its way into our system will be expelled a few days after being consumed.
How Much Arsenic Is There in Food and Drinking Water?
Public drinking water in America is mandated to no more than 10 parts per billion of arsenic. However, water sourced from private wells that have not undergone any type of filtration or cleaning procedure can have significantly higher levels of the harmful chemical. This is especially true for those areas located on arsenic-based bedrock, through which the groundwater flows.
Unlike in water, however, there is no set federal limit for "what is arsenic used for in food". In fact, arsenic can be found in fruits, vegetables, and grains, most especially rice. These three food groups are responsible for majority of dietary exposure to arsenic, with vegetables covering 24% of dietary arsenic intake, fruits covering 18%, and rice covering 17%. This already totals to 59%, more than half of our total dietary exposure to arsenic.