 |
Also see:
|
Cadmium
Description: Cadmium (C.A.S. 7440-43-9) is a naturally-occurring element in the earth's crust. Pure cadmium is a soft silver-white metal, but this form is not common in the environment. Cadmium is most often found in combination with other elements, such as oxygen (cadmium oxide), chlorine (cadmium chloride), or sulfur (cadmium sulfide). Most cadmium used in the United States is a soft, bluish metal or grayish powder obtained as a by-product from the treatment of copper, lead and iron ores. Thirty-five percent of cadmium is used for metal plating, 25 percent for nickel-cadmium and other batteries, 20 percent for pigments, 15 percent for plastic stabilizers, and 5 percent for other uses, including pesticides, alloys, and chemical reagents and/or intermediates. Chemical and physical properties: Cadmium and its compounds are stable, with high melting points and low volatility. In water, they range from quite soluble (cadmium chloride) to practically insoluble (cadmium oxide). Cadmium is a flammable powder, and it produces toxic fumes when it burns. Synonyms for cadmium include C.I. 77180, C.I.77180, and cadmium metal: cadmium. Identification: Health effects: Cadmium, especially cadmium oxide, is a probable cancer-causing agent in humans. There is evidence that cadmium causes prostate and kidney cancer in humans, and it has been shown to cause lung and testes cancer in animals. It is a probable teratogen in humans; it may damage the testes and may affect the female reproductive cycle. Inhalation of cadmium oxide fumes is acutely toxic to the respiratory epithelium, and high exposures result in severe bronchial and pulmonary irritation. Repeated low exposures can cause permanent kidney damage, which can go unnoticed without testing until the condition is severe. The kidney damage can lead to kidney stones and other health problems. Emphysema and/or lung scarring can occur from a single high exposure or from repeated lower exposures. Long-term exposure can cause anemia, loss of sense of smell, fatigue, and/or yellow staining of teeth. Short-term health effects include a flu-like illness with chills, headache, aching and/or fever. High exposures can cause rapid and severe lung damage, with shortness of breath, chest pain, cough, and a buildup of fluid in the lungs. In severe cases, death or permanent lung damage occurs. High exposure to cadmium may cause nausea, salivation, vomiting, cramps, and diarrhea. Exposure Values: Economics: U.S. manufacturers of cadmium are ASARCO Inc, Denver, CO and Flour Corp, Irvine, CA. Regulation: Cadmium is regulated by EPA and some states under the Clean Water Act's National Pollutant Discharge Elimination System and General Pretreatment Regulations. EPA offices overseeing regulations and guidelines applicable to cadmium include the Offices of Air Quality Planning and Standards; of Drinking Water; of Toxic Substances; of Solid Waste; of Pesticide Programs; and of Emergency and Remedial Response. The Occupational Safety and Health Administration sets permissible exposure limits for occupational exposures to cadmium. Under Section 313 of the Emergency Planning and Community Right to Know Act of 1986, releases of more than one pound of cadmium 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 |