Airborne Hexavalent Chromium in Southwestern Ontario

Abstract

This study reports the first field measurements of airborne hexavalent chromium (Cr(vi)) in southwestern Ontario. Hexavalent chromium was identified as an inhalation carcinogen and an air toxic of concern during the 1991-93 Windsor Air Quality Study. The results of that study indicated that approximately 20% of the routinely monitored ambient airborne chromium (Cr) was in the hexavalent form. In addition, the range of carcinogenic health risks attributable to airborne Cr(vi) was determined to be between 1.4 × 10 -6 and 3.0 × 10 -4 for people living in the Windsor area. During the summer of 1993, analyses of concurrent indoor and outdoor 24-hour air quality samples taken at 33 residences in Hamilton resulted in geometric mean Cr(vi) concentrations of 0.20 ηg/m 3 and 0.55 ηg/m 3 , respectively, and little or no relationship between the indoor and outdoor sample sets. During the summer of 1994, an airborne Cr(vi) size-fractionation study was conducted in Hamilton, the results of which suggested that the majority of the Cr(vi) was in the inhalable fraction.

Cancer risk assessment of selected hazardous air pollutants in Seattle

“…Species without any unit risk values were not included in the risk assessment process. The unit risk of chromium was adjusted by multiplying a factor of 0.2, assuming that approximately 20% of the ambient airborne chromium was in the toxic hexavalent form (Bell and Hipfner, 1997). The unit risk for nickel was adopted from the unit risk for nickel subsulfide in IRIS, assuming that all the monitored nickel was in the insoluble and carcinogenic form.…”

Distribution of Airborne Hexavalent Chromium Concentrations in Large Industrial Complexes in Korea

“…According to Bell and Hipfner (1997), the mean Cr(VI) level in industrial areas in Hamilton, where a number of steel manufacturing companies are located, was 0.55 ng/m 3 . Li et al (2002) reported that the Cr(VI) levels in Sydney, Australia were 0.14 in a residential area and 0.2-1.3 ng/m 3 in an industrial area.…”

Sampling and analysis considerations for the determination of hexavalent chromium in workplace airThis article was prepared by governmental employees of the United States of America and the United Kingdom as part of their official duties, and legally may not be copyrighted in the USA or the UK.

“…2 ), whereas Cr(III) exists as cations (Cr 31 , Cr(OH) 21 , Cr(OH) 2 1 ). 42 Protonation/deprotonation of Cr(III) is kinetically rapid, 41 further emphasizing the importance of solution acidity or basicity.…”

“…19,20 Almost all Cr(VI) present in the environment comes from anthropogenic sources, as this species is ordinarily converted to Cr(III) via natural and often rapid chemical reduction. [21][22][23] In occupational settings, airborne Cr(VI) compounds can be found in a wide range of concentrations and particle sizes, and also in the presence of Cr(III) compounds with widely varying ratios. 24 The toxicity of airborne Cr(VI) compounds is quite varied and depends in part on the solubility of the Cr(VI) compound in question.…”