Its stable form is a silver-gray brittle crystalline solid that does not exhibit any characteristic smell or taste. Owing to its membership to the Va group of the periodic table, it readily combines with other elements to produce organic arsenic compounds (when in combination with carbon and hydrogen) and inorganic arsenic compounds (when in combination with oxygen, chlorine and sulfur) (Marcus, 2006; Nriagu, 1994).
The occurrence of arsenic in the environment can be considered as an important notion in the study of the effects and toxicology. The name of Arsenic is equated to poison, due to the effects that it can bring about to the different organisms and components of the environment. The said chemical can be considered as toxic due to its reactivity. It occurs in different forms that are commonly reactive due to the fact that it is considered as a heavy metal but its use in different industries and the by-products produced intensifies the effects of arsenic (Marcus, 2006).
Although natural arsenic can be found in certain amounts in the environment, accumulation increases the hazardous effect of the chemical. Effects of arsenic can be attributed to the exposure in relation to the industrial process and accumulated amounts in the environment. For this reason, it is important to consider the need to regulate the application of arsenic in different industries.
e used by nobles including the Italian family of the Borgias who used arsenic for political assassinations, and was regarded to be the poison that killed Napoleon, thus earning its moniker as the "Poison of Kings" (Nriagu, 1994).
Aside from being an agent for murder, arsenic has largely been used as an ingredient in insecticides and herbicides. It has also been used in dyes, paints and other coloring agents including the green pigment Emerald Green which had been widely used by Impressionist painters and was thought to have caused Van Gogh's neurological disorder, Cezanne's diabetes and Monet's blindness. Currently, the arsenic compound gallium arsenide is used in the semiconductor industry to produce integrated circuits. Arsenic compounds are also used in the manufacture of glass and the smelting of copper and bronze. Chromated copper arsenate (CCA) is also used to preserve timber (Nriagu, 1994).
Natural and Man-Made Sources of Environmental Arsenic
Arsenic is naturally present in small concentrations in rock, soil, water and air arsenopyrite is among the 200 mineral species that arsenic is present. The chemical can be found prevalent in any types of environment, thus any exploitation in the use of the said chemical can cause imbalance.
A. Atmospheric Arsenic
One-third of the arsenic present in the atmosphere is from volcanic activity. The release of methylarsines by microorganisms also contributes to atmospheric arsenic. Inorganic arsenic compounds are also found in groundwater in countries like Bangladesh as a result of geologic activity. Organic arsenic compounds in the form of arsenobetaine and arsenocholine are found in marine organisms and a few terrestrial organisms (Brimblecombe, 1979).
Atmospheric arsenic concentrations will range from 0.02 ng/m3 to