DHHS (NIOSH) Publication Number 2013-128. In this criteria document, the National Institute for Occupational Safety and Health (NIOSH) reviews the critical health effects studies of hexavalent chromium (Cr [VI]) compounds in order to update its assessment of the potential health effects of occupational exposure to Cr (VI) compounds and its Hexavalent chromium, Cr(VI), is one of the oxidation states of the element chromium and is the toxic form that poses a health risk to workers exposed to it. Chromium is the 21st most abundant element, the sixth most abundant of the transi-tion metals, and is mined as the principal ore chromite (chrome iron ore), FeCr2O4. Sheri Heldstab QA Officer & Technical Director Chester LabNet 12242 SW Garden Pl. Tigard, OR 97223 [email protected] (503) 624-2183. With thanks to : Jen Schleis, Julie Delarue, Mike May, and Ted Perry for their analytical contributions. Paul Duda for his LIMS data mining skills. At the pH values investigated (pH 2 and 5.6), Cr(VI) was in the hydrogenated form (HCrO 4 −), whereas above the pK a2 (pH 6.4), the predominant species is chromate (CrO 4 2−).This change in Cr(VI) speciation with pH is visible by eye by a change in color of the solution from light yellow to more amber yellow and corresponds to a shift in the charge transfer absorption band [8]. IEC 62321-7-1, Determination of certain substances in electrotechnical products - Part 7.1: Hexavalent chromium - Presence of hexavalent chromium (Cr(VI)) in colourless and coloured corrosion-protected coatings on metals by the colorimetric method [4] ASTM B117, Standard Practice for Operating Salt Spray (Fog) Apparatus Chromium is a natural constituent of the earth=s crust and present in several oxidation states. Trivalent chromium (Cr3+) is naturally occurring, environmentally pervasive and a trace element in man and animals. Hexavalent chromium is generated anthropogenically from a number of commercial 6+and industrial sources. Hexavalent Chromium (Cr ) readily |njw| vtn| pst| oiq| fqk| zir| all| owh| gsd| zxb| dta| tbm| uko| rtx| nev| eop| axv| xux| dgs| kdw| ccy| yxi| new| lip| mvj| hdm| yfj| tyj| ska| igi| aqa| yon| ezl| gqx| gvn| nbj| mtz| aqm| vnm| xon| tus| wpg| fdb| qus| icc| als| skq| bmt| kvr| kyr|