a chemical element, atomic number 33, atomic weight 74.92. (See Appendix 6.) It is toxic by inhalation or ingestion, and
carcinogenic (see
arsenic poisoning). In nature it occurs usually as one of its salts; in human environments it is often a pollutant in mining regions, and is used in dyes, household pesticides, and compounds used in agriculture. Arsenic compounds called
arsenicals were formerly widely used in medicine.
arsenic poisoning poisoning due to systemic exposure to inorganic pentavalent arsenic. Arsenic is cumulative, storing permanently in hair, nails, and bone, and children are particularly susceptible. Arsenic is odorless and flavorless and has been found in elevated levels in the drinking water that flows through arsenic-rich rocks, leading to serious health problems in some countries. The antidote for arsenic poisoning is
dimercaprol.
Acute arsenic poisoning, which may result in shock and death, is marked by skin eruptions, swelling of eyelids and limbs, vomiting, diarrhea, and cramps.
Chronic arsenic poisoning (called also
arsenism), due to ingestion of small amounts over a long period of time, is marked by skin pigmentation with scaling, keratosis of the palms and soles, white lines on the fingernails, peripheral neuropathy, and confusion.