The Agency for Toxic Substances and Disease Registry (ATSDR) prepared this health consultation to provide support for assessing the public health implications of hazardous chemical exposure, primarily through drinking water, related to releases of chromated copper arsenate (CCA) in the port of Djibouti. CCA from a shipment, apparently intended for treating electric poles, is leaking into the soil in the port area. CCA is a pesticide used to protect wood against decay-causing organisms. This mixture commonly contains chromium(VI) (hexavalent chromium) as chromic acid, arsenic(V) (pentavalent arsenic) as arsenic pentoxide and copper (II) (divalent copper) as cupric oxide, often in an aqueous solution or concentrate. Experimental studies of the fate of CCA in soil and monitoring studies of wood-preserving sites where CCA was spilled on the soil indicate that the chromium(VI), arsenic and copper components of CCA can leach from soil into groundwater and surface water. In addition, at CCA wood-preserving sites, substantial concentrations of chromium(VI), arsenic and copper remained in the soil and were leachable into water four years after the use of CCA was discontinued, suggesting prolonged persistence in soil, with continued potential for leaching. The degree of leaching depended on soil composition and the extent of soil contamination with CCA. In general, leaching was highest for chromium(VI), intermediate for arsenic and lowest for copper. Thus, the potential for contamination of sources of drinking water exists. Although arsenic that is leached from CCA-contaminated soil into surface water may accumulate in the tissues of fish and shellfish, most of the arsenic in these animals will be in a form (often called fish arsenic) that is less harmful. Copper, which leaches less readily than the other components, can accumulate in tissues of mussels and oysters. Chromium is not likely to accumulate in the tissues of fish and shellfish. Limited studies of air concentrations during cleanup of CCA-contaminated soil at wood- preserving sites showed that air levels of chromium(VI), arsenic and copper were below the occupational standards. Workers directly involved in the repackaging, containment or cleanup of leaking containers of CCA or of soil saturated with CCA, however, may be exposed to high levels of CCA through direct dermal contact, inhalation of aerosols or particulates and inadvertent ingestion. Few studies have been conducted on the health effects of CCA. CCA as a concentrated solution is corrosive to the skin eyes and digestive tract. Studies of workers exposed to CCA in wood-preserving plants have not found adverse health effects in these workers, but the studies involved small numbers of workers and therefore are not definitive. People exposed to very high levels of CCA, from sawing wood that still had liquid CCA in it or from living in a home contaminated with ash containing high levels of chromium(VI), arsenic and copper, experienced serious health effects including nosebleeds, digestive system pain and blee...
The production of arsenic usually occurs as a by‐product of smelting of copper, lead, or gold ores. It has been estimated that the atmospheric flux of arsenic was ∼73,540 tons/year, 60% of which was of natural origin, and the rest was derived from anthropogenic sources. 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 gallium arsenide and indium arsenide. Fowler's solution (potassium arsenite‐As 3+ ) 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 past 20 years. More recently, As 3+ has been effectively used to treat acute 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 anthelmintic and antiprotozoal 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 that of 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 group VA of the periodic table together with arsenic and antimony, and 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.
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