Arsenic has long been known as a poison. The element arsenic occurs naturally in soil and many kinds of rock. It can exist in toxic and nontoxic forms. Unlike mercury, the toxic forms of arsenic are not organic forms but rather inorganic forms. As3+ and As5+ and their metabolites account for the toxicity of arsenic.
Inorganic arsenic compounds have been used as pesticides but are no longer used in agriculture. Small quantities of arsenic are still used in alloys in lead-acid batteries. Some arsenic compounds may also be found in semiconductors and light-emitting diodes. Nontoxic forms of arsenic are present in some foods like shellfish, cod, and haddock.
Absorption:
Direct contact with arsenic trioxide dust can cause localized skin irritation, but systemic absorption through the skin is negligible. Ingestion is the primary route of arsenic toxicity. Arsenic trioxide is the main form encountered in poisoning cases. Ingested arsenic trioxide is quickly absorbed and significant tissue and organ damage can result. Most acute intoxications are due to suicidal or intentional homicidal ingestion. Chronic exposures can also result from drinking and consuming water and foods with high arsenic concentrations.
