Chromium, Hexavalent, In Settled Dust Samples.7703 as a field portable method of analysis of hexavalent chromium. Chromium, Hexavalent by Field-Portable Spectrophotometry.This method is similar to OSHA Method ID-215. Describes the sample collection and analysis of hexavalent chromium. Chromium, Hexavalent by Ion Chromatography.National Institute for Occupational Safety and Health (NIOSH) Methods Describes the procedures for wipe sampling of hexavalent chromium. The following methods have been adopted by many laboratories for the analysis of chemical compounds. OSHA has developed and validated methods for use by the Salt Lake Technical Center (SLTC) laboratory. Information available on the pages includes chemical identification and physical properties, exposure limits, sampling information, and additional resources. It compiles information from several government agencies and organizations. OSHA's premier one-stop shop for occupational chemical information. OSHA Cr(VI) standards for general industry ( 1910.1026), shipyards ( 1915.1026), and construction ( 1926.1126) require employers to assess potential employee exposed to chromium (VI). The following references provide information on exposure limits and analytical methods used to evaluate hexavalent chromium exposure. Occupational exposure to hexavalent chromium can occur from inhalation of dusts, mists, or fumes containing hexavalent chromium, or from eye or skin contact. The US Environmental Protection Agency (EPA) applies an emissions limit on chrome 6 from hard chrome plating facilities.Exposure and Controls Evaluating Exposure Other adverse health effects associated with chromium-6 exposure, according to the US National Institute for Occupational Safety and Health (NIOSH), include skin irritation or ulceration, allergic contact dermatitis, occupational asthma, nasal irritation and ulceration, perforated nasal septa, rhinitis, nosebleed, respiratory irritation, nasal cancer, sinus cancer, eye irritation and damage, perforated eardrums, kidney damage, liver damage, pulmonary congestion and edema, epigastric pain, and erosion and discoloration of one's teeth. Hexavalent chromium is classified as a human carcinogen based on excess lung cancer found in heavily exposed workers through inhalation in chrome plating and chromate pigment production. Levels of chromium in these conditions are usually well-below those that would be considered dangerous. In drinking water the level of chromium is usually low as well. The level of chromium in air and water is generally low. People who smoke tobacco also have a higher chance of exposure to chromium. Hexavalent chromium is a danger to human health, mainly for people who work in the steel and textile industry. Only a small part of the chromium that ends up in water will eventually dissolve. In water chromium will absorb on sediment and become immobile. Chromium in soils strongly attaches to soil particles and as a result it will not move towards groundwater. Most of the chromium in air will eventually settle and end up in waters or soils. Most industrial output is to water but coal burning also increases air concentration. Hexavalent chromium finds its way into the environment naturally or through manufacturing activities. The use of chromium in welding produces hexavalent chromium as a by-product. Hexavalent chromium is used to produce CCA (chromated copper arsenate) that is applied as a preservative in the treatment of structural timber. It is used in chrome plating and as an alloy in the production of stainless steel, as well as in anti-corrosion and conversion coatings. Its properties include corrosion-resistance, durability and hardness. However, its ease of reaction with other elements is the main reason why hexavalent chromium is considered a major health hazard. This ability to react can produce hard coatings. It can easily gain electrons from other elements, meaning that it can easily react with them. Hexavalent chromium occurs naturally but it is usually produced by industrial process. The most common forms of chromium in the environment are trivalent chromium (chromium-3), hexavalent chromium (chromium-6) and the metal form of chromium (chromium-0). Chromium is unstable in oxygen, it immediately produces a thin oxide layer that is impermeable to oxygen and protects the metal below. It does not tarnish in air, when heated it burns and forms the green chromic oxide. Its colour is silver-grey and it can be highly polished. Chromium is a lustrous, brittle, hard metal.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |