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Arsenic
Description: Arsenic (C.A.S. 7440-38-2) is a naturally occurring element in the earth's crust. Pure arsenic is a gray-colored metal, but is rare in the environment. Arsenic is usually found combined with one or more other elements such as oxygen, chlorine, and sulfur. In combination, such arsenic is referred to as inorganic arsenic. Arsenic combined with carbon and hydrogen is referred to as organic arsenic. The organic forms are usually less toxic than the inorganic forms. Arsenic is produced primarily as a by-product from the operation of copper and lead smelters. The major uses of arsenic in the U.S. are as wood preservatives (74 percent of all arsenic), agricultural products (19 percent), glass (3 percent), nonferrous alloys (2 percent), and other uses (2 percent). Chemical properties: Synonyms for arsenic are arsenic-75, metallic arsenic, arsenic black, arsenicals, and colloidal arsenic. The inorganic arsenic compounds are solids at normal temperatures and are not likely to volatilize. In water, they range from quite soluble (sodium arsenite and arsenic acid) to practically insoluble (arsenic trisulfide). Some organic arsenic compounds are gases or low-boiling liquids at normal temperatures. Poisonous gas is produced by arsenic in a fire. Arsenic near acid or acid mist can release a very deadly gas, arsine. Twenty-one arsenic compounds are
considered to be of concern because of their toxicity and/or presence in the environment. Identification: Health effects: Large doses of inorganic arsenic can cause death. Arsenic is a known poison and a known carcinogen that has been shown to cause skin and lung cancer. It also may damage a developing fetus and should be handled as a potential teratogenic agent
(causing developmental malformations), as some arsenic compounds are known teratogens. Oral exposure to inorganic arsenic can cause digestive tract pain, nausea, vomiting, diarrhea, decreased production of red and white blood cells, abnormal heart function, blood vessel damage, liver and/or kidney injury, and impaired nerve function, causing a "pins and needles" effect in the feet and hands. Oral exposure to inorganic arsenic can also cause a pattern of skin abnormalities, including the appearance of dark and light spots on the skin, and small "corns" on the palms, soles, and trunk, which may ultimately progress to skin cancer. In addition, arsenic ingestion is reported to increase the risk of cancer inside the body, especially in the liver, bladder, kidney, and lung. Skin contact with arsenic can cause burning, itching and a rash. Breathing arsenic can irritate the nose and throat; eye contact can cause red, watery eyes and irritation. Long-term exposure can cause an ulcer or hole in the "bone" dividing the inner nose, hoarseness, and sore eyes. Populations relying on groundwater or surface water near geologic or man-made sources of arsenic may receive higher than typical exposures. These areas include industrialized areas and areas where large quantities of arsenic are disposed of in
landfills, as in parts of Pennsylvania, southern New York, Ohio, Indiana, and Washington; areas of high historical pesticide use, with soil low in available ferrous and aluminum hydroxides; and areas of high natural levels of arsenic-containing mineral deposits, as in the western U.S. Populations in the area of copper and other types of metal smelters may be exposed to above-average levels of arsenic both through the air and as a result of atmospheric deposition in soil and water. Individuals with protein-poor diets or choline (of the Vitamin B complex) deficiency may be more sensitive to arsenic than the general population. Exposure Values: Economics: U.S. manufacturers of arsenic are Alfa Products, Morton Thiokol Inc, Danvers, MA; Atlantic Equip Engrs, Div of Micron Metals Inc, Bergenfield, NJ; Atomergic Chemetals Corp, Plainview, NY; Belmont Metals Inc, Brooklyn, NY; Cerac Inc, Milwaukee, WI; Metalsmart, Great Neck, NY; Noah Chemical, Div Noah Ind Corp, Farmingdale, NY; Var-Lac-Oid Chem Co, St, Elizabeth, NJ; Schumacher JC, Co, Oceanside, CA; Anderson Physics Labs, Inc, Urbana, IL; Ferer, Aaron, & Sons Co, Omaha NE; GFS Chemicals Inc, Columbus, OH; and Kraft Chemical Inc, Melrose Park, FL. No arsenic producers currently operate in the U.S., and all raw materials for production of arsenic-containing products must be imported. Until 1985, arsenic trioxide was produced in the U.S. only at the ASARCO smelter in Tacoma, Washington. Annual production was 7,300 metric tons (16 million pounds) in 1983, but production decreased to 2,200 metric tons (4.8 million pounds) in 1985. In 1979, the U.S. imported 8,940 metric tons (19.5 million pounds) of arsenic in the form of arsenic metal or inorganic arsenic compounds. By 1985, imports had risen to 19,000 metric tons (41.5 million pounds) and increased to nearly 28,000 metric tons (61.2 million pounds) in 1986 after domestic production ceased. Regulation: The Occupational Safety and Health Administration issues permissible exposure limits for inorganic arsenic; the Food and Drug Administration issues permissible levels of arsenic in muscle meats, edible meat by-products, and eggs. EPA offices overseeing regulations and guidelines applicable to arsenic include Air Quality Planning and Standards, under National Emissions Standards for Hazardous Air Pollutants; Water Regulations and Standards, under the National Pollutant Discharge Elimination System; Drinking Water; Emergency and Remedial Response; Solid Waste; and Pesticide Programs. Under Section 313 of the Emergency Planning and Community Right to Know Act of 1986, releases of more than one pound of arsenic into the air, water, and land must be reported annually and entered into the Toxic Release Inventory (TRI). National Overview of 1998 Toxics Release Inventory See EPA's Toxic Release Inventory. Notations: The NIOSH recommended exposure limits (RELs) are time-weighted average (TWA) concentrations for up to a 10-hour workday during a 40-hour workweek. A short-term exposure limit (STEL) is designated by "ST" preceding the value; unless noted otherwise, the STEL is a 15-minute TWA exposure that should not be exceeded at any time during a workday. A ceiling REL is designated by "C" preceding the value. Any substance that NIOSH considers to be a potential occupational carcinogen is designated by the notation "Ca." The OSHA permissible exposure limits (PEL) are found in Tables Z-1, Z-2, and Z-3 of the OSHA General Industry Air Contaminants Standard (29 CFR 1910.1000). Unless noted otherwise, PEL are TWA concentrations that must not be exceeded during any 8-hour workshift of a 40-hour workweek. A STEL is designated by "ST" preceding the value and is measured over a 15-minute period unless noted otherwise. OSHA ceiling concentrations (designated by "C" preceding the value) must not be exceeded during any part of the workday; if instantaneous monitoring is not feasible, the ceiling must be assessed as a 15-minute TWA exposure. In addition, there are a number of substances from Table Z-2 (e.g., beryllium, ethylene dibromide, etc.) that have PEL ceiling values that must not be exceeded except for specified excursions. For example, a "5-minute maximum peak in any 2 hours" means that a 5-minute exposure above the ceiling value, but never above the maximum peak, is allowed in any 2 hours during an 8-hour workday. Information Sources:
Originally published in Environment Writer by the National Safety Council. Reprinted with permission. Environment Writer Metcalf Institute for Marine and Environmental Reporting University of Rhode Island Graduate School of Oceanography Office of Marine Programs Narragansett, RI 02882 Tel: 401-874-6211; Fax: 401-874-6485 Disclaimer * Copyright 2002-2006 * All rights reserved. * University of Rhode Island |