Concise and comprehensive toxicological review paper on arsenic

Toxicological report: Arsenic
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1 Introduction
Millions of people worldwide are affected by toxicity caused by Arsenic metal. Contamination cause by arsenic is a global issue. This happens when arsenic which naturally occurs in geological sources leach into water bodies and aquifers and contaminates drinking water. Mining and other manufacturing industries are also sources of arsenic toxicity. In addition, conventional medicines also contain this toxicity. Arsenic trioxide is also used for medicinal purpose in the treatment of severe promyelocytic leukemia. Absorption in to the body occurs in two ways; assimilation from the small intestines and from skin contact and inhalation. The former is the major way in which arsenic enters the body. Arsenic poisons the body by disabling enzyme functions. Up to 200 enzymes are effected mostly those associated with DNA synthesis and repair and provision of cellular energy. Symptoms of acute arsenic poisoning include abdominal pain, nausea, diarrhea, and vomiting. This often affects multiple systems in the body since it is carcinogenic. Arsenic prone areas in the world include Bangladesh and West Bengal in India. These two regions are the most hit with about 79 million people exposed to arsenic in Bangladesh and 40 million in West Bengal. The world health organization allows a maximum of 50 μg/l ingestion of arsenic in drinking water. However in these regions the amounts ingested exceed this amount. There is no treatment for acute arsenic poisoning as at now but scientists have come up with antioxidants even though their workability has not been proved. The most effective way to control arsenic poisoning is by avoiding unsafe drinking water or switching to better water supply (National Academy Press.52, 1999). 
2 CHEMISTRY AND TOXICITY
Arsenic exists in two oxidation states either in trivalent or pentavalent form. This is arsenite (As2O3 ) and arsenate (As2O5) respectively. Arsenic in the trivalent form is said to be more toxic than in pentavalent form up to 60 times. It is important to comprehend that toxicity only arises from inorganic arsenic since the organic arsenic is non toxic. Toxicity by inorganic arsenic alters DNA replication and repair by deactivating enzymes associated with it. Arsenic replaces phosphate in the body in cases of ATP among other high energy compounds. Another way arsenic poisons the body is by producing reactive oxygen intermediates (Federal Register 2001). This usually happens during the redox cycle and metabolic oxidation involved with the preoxidation of fat and damaging of the DNA. This is often triggered by trivalent arsenic such as sulfhydryl when it accumulates in major organs and tissues like lungs, liver, kidney, spleen, skin and hair.
3 TOXICOKINETICS
Arsenic Exposure
There are many ways by which individuals are exposed to arsenic depending on their environment. Mostly exposure occurs by ingestion of ar...