Cr^VIexposure and biomarkers: Cr in erythrocytes in relation to exposure and polymorphisms of genes encoding anion transport proteins

Abstract

A total of 195 subjects, including 141 exposed workers and 54 farmers, were recruited in China to evaluate the usefulness of chromium (Cr) in erythrocytes as a biomarker of exposure to Cr VI . The levels of Cr in red blood cells (RBC) were remarkably elevated even in a group of workers routinely exposed to Cr VI as low as 5-15 μg m −3 and showed a significant exposure-response trend over the exposure range from 0.002 to 1152 μg m −3 (p<0.0001). Multiple linear regression analyses indicated that age and cigarette smoke were not associated with Cr in RBC. However, female subjects had lower Cr in RBC compared with their male counterparts for about the same exposure levels (p<0.05).The genotypes of band III, which encodes for anion transport protein and may regulate across cell membranes, were also identified and included for analysis. The ratios of Cr in RBC to Cr VI exposure were higher in subjects with a wild genotype than in those who had heterozygous or homozygous variant alleles. However, the difference was not statistically significant probably due to the limited number of participating subjects. In addition, 15 of the 141 workers were selected for multiple exposure monitoring and blood sample collections to evaluate the inter-and intraindividual variations of Cr in RBC. Compared with the personal exposure levels, Cr in RBC had small intraindividual variations with a reliability coefficient of 0.88. The study suggests that Cr in RBC may serve as a sensitive and reliable biomarker for long-term exposure to Cr VI .

Detection of Urinary 8-hydroxydeoxyguanosine (8-OHdG) Levels as a Biomarker of Oxidative DNA Damage among Home Industry Workers Exposed to Chromium

“…Cr (VI) exposure can be traced by measuring the chromium level in the blood or urine. The chromium level in the blood or urine reflects the current exposure, but not reflects total chronic chromium exposure including Cr (III) and Cr (VI) [35]. Cr III was quickly exerted through urine and less poisonous because of the poor permiability membrane while Cr (VI) compound penetrate membrane and induced the DNA damage and carcinogenesis [36].…”

Cicer arietinum growth promotion by Ochrobactrum intermedium and Bacillus cereus in the presence of CrCl3 and K2CrO4

“…Hexavalent chromium is more mobile and can easily pass through biological membranes, but inside cells it is converted to Cr (III) which cannot pass through membranes (Qu et al 2008). In addition, plants have also developed various mechanisms to combat the toxicity of metals, and sometimes accumulate excess amounts of metals in various organelles like vacuoles, etc.…”

Chronic occupational exposure to hexavalent chromium causes DNA damage in electroplating workers

“…While high-level chromium exposure has generally been considered to have carcinogenic effects [19-21], the health concerns regarding low-level chromium exposure have failed to reach a consensus [22,23]. Compared to industries with high-level chromium exposure such as chrome plating, electroplating is generally considered to have much lower-level chromium exposure [25].…”

“…Previous studies on Cr(VI) toxicity mainly focused on relatively high-level chromium exposure, such as chrome-plating, chromium compound manufacturing and polishing [19-21]. Recent studies on exposure to relatively low levels of chromium such as at electroplating and tannery workplace have yielded inconsistent results [22,23].…”