Arsenic, Antimony, and Bismuth

Abstract

The production of arsenic usually occurs as a by-product of copper smelting, and is approximately in the range of 50,000–100,000 tons per year but this is a rough estimate based on previous global estimates by WHO and the impact of increasing use of As in the global semiconductor industry. This element is used for a variety of industries including glass manufacturing, wood preservatives, metal alloys, pesticides and in the manufacture of semiconductors as a dopant for silicon-based semiconductors or the production of III-V semiconductors such a gallium arsenide and indium arsenide. Fowler's solution (potassium arsenite-As3+) had been used in the past to treat a variety of clinical illnesses such as leukemia and skin disorders such as psoriasis and bronchial asthma but was supplanted by more modern chemotherapeutic agents during the last 20 years. More recently, As3+ has been effectively used to treat promyelocytic leukemia. Human exposure to inorganic arsenic may occur via air, food, and water. Persons consuming seafood generally have higher total intakes of arsenic, but the chemical forms of arsenic are primarily arsenobetaine and other methylated species of relatively low toxic potential. Arsenic is a general systemic poison whose toxic and medicinal properties have been known for several thousand years. The carcinogenic properties of inorganic arsenicals in humans have been known for several hundred years. Sb as an element is a brittle, flaky, crystalline (hexagonal) silver-white metal. It does not react with air at room temperature but burns brightly when heated, and forms white fumes. It is a poor conductor of electricity and heat. Antimony occurs in tri- (+3) and pentavalent (+5) compounds and is found in the earth's crust mostly associated with sulfur as stibnite and in ores associated with arsenic. Antimony is a group VA element of the periodic table and it has many of the same chemical and biological properties as the element arsenic. Stibine gas is odorless. Exposure to antimony at high levels may result in a variety of adverse health effects. For example, breathing high levels of antimony and some of its compounds can irritate the eyes and lungs and can cause problems with the heart, lungs, and stomach. Historically, antimony compounds were used as emetics and expectorants. Recently, antimony compounds, such as tartar emetic and sodium stibogluconate, are used as antihelminthic and antiprotozoic drugs in treating parasitic diseases and infections. It plays no role in nutrition and is a nonessential element. Bismuth is a brittle, white, crystalline metal that has a pinkish tint. It is the most diamagnetic of all metals, and its thermal conductivity is lower than any metal except mercury. In addition, bismuth has high electrical resistance and the highest Hall effect of any metal. Inorganic salts of bismuth are poorly water soluble; solubility is influenced by the acidity of the medium and the presence of additional certain compounds containing sulfhydryl or hydroxyl groups. Bismuth belongs to the VA group of the periodic system together with arsenic and antimony, and it forms compounds in the +3 and +5 oxidation states. Bismuth occurs in the native form; however, it is found largely in nature in minerals such as bismite, bismuthinite, and bismutite and is usually associated with sulfide ores of lead and copper and tin dioxide. Human exposure to bismuth and bismuth compounds is quite limited, except for its use in medicine where it has been prescribed for more than a century. Occupational and environmental exposure to bismuth and its toxicological significance are still unknown. Keywords: Arsenic; Antimony; Bismuth; Arsenic compounds; Antimony compounds; Bismuth compounds; Physical and chemical properties; Production; Use; Toxic effects; Exposure assessment; Environmental impact; Standards; Regulations; Guidelines; Cancer; Skin; Excretion; Neurological effects; Gastrointestinal effects; Mann model; Hematological effects