Arsenic

Abbreviation: As

Chemical Characteristics

Arsenic is classified as a metalloid and has properties of both metals and non-metals.
When arsenic is mixed with oxygen, it forms arsenic oxide. It can be identified as a blue
flame and it has a garlic like odor. Arsenic only reacts with hot acids and doesn't dissolve
in water or cold substances.

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Physical Characteristics

Most common arsenic is shiny, gray, brittle, and metallic-looking. Another form is a yellow crystalline, but is rare. An arsenic solid is formed when the gas is cooled quickly. When arsenic is heated it doesn’t melt but it turns into a gas, this process is called sublimation.

Boiling Point: 614ºC
Melting Point: 817ºC
Critical Temperature: 1427ºC


Arsenic in Nature

Arsenic is never found as a pure element; it is only found as a compound. They are found in realgar, orpiment, and arsenolite minerals. In the Earth's crust there is around 5 parts per million of arsenic. The world's largest producers of arsenic are China, Chile, Belgium, the Philippines, and Mexico. Arsenic is not produced in the United States.

Arsenic Recovered and Purified

To recover and purify arsenic, heat the product to cause the arsenic to disperse in a vapor/gas as a sulfide. The arsenic sulfide is mixed with the air and produces an arsenic trioxide.

Arsenic Uses

Arsenic is a poisonous element and was used in insecticides and rat poison. Arsenic was also used in bullets to make them harder and rounder. There is a minimal amount of arsenic in parts of car batteries. A compound of arsenic and gallium arsenide is used to make the light that emits from calculators, clocks, and digital watches. Today, the amount of arsenic used is continuing to decrease.

Arsenic Products

Consumer products containing arsenic are pesticides, fungicides, weed killers, preserved wood and wood treatment products.
Many consumers use wood preserving so that it can be used outdoors for children's playgrounds.


How are these products used?
Pesticides are used to keep insects out of gardens, weed killers to kill the weeds in them, and fungicides to kill off the fungi.

Who uses the products?
Common households use the pesticides and weed killers in gardens to kill off unwanted life. Also, many wood manufacturers use arsenic to preserve their wood.

Are there any environmental concerns due to this use?
The environmental concerns for arsenic are generally low. But where the arsenic concentrations have elevated were usually due to natural processes such as the amount of arsenic in the fish. High amounts of arsenic can be toxic to many organisms, such as humans, some to which that can lead to cancer, blindness, and may be fatal. Arsenic can reduce the process of photosynthesis. Arsenic contamination to water has occurred when mining from natural deposits. The compounds made when preserving wood often enter into the soil and drain into the groundwater. The contamination of water by arsenic is the most important environmental concern.

How are waste products disposed of?
Arsenic products should be properly disposed at hazardous waste collection centers. They should not be poured down the drain, on the ground, or in the sewer because the chemicals could disrupt the water supplies or septic systems. Preserved wood that contains arsenic should not be burns or sawed because the sawdust could be inhaled and can be harmful. Therefore the preserved wood should be brought to the hazardous waste centers also.

Is Arsenic an important nutrient?

Arsenic isn't a very important nutrient but it is in almost everyone's diet everyday. Arsenic is known to treat some digestive problems but it is not clear how arsenic works in the body. Each day there is about 140mcg of arsenic in a typical diet. Arsenic is naturally in breads, meats, starchy vegetables, cereals, and fish.

By: Sara A.