Chromium status of tannery workers in relation to metabolic disorders

Abstract

Chromium (Cr), being an excellent tanning agent, is widely used in the leather industry. In the process of leather production, tannery workers are exposed to either inorganic Cr(III) compounds or Cr bound to proteins (leather dust). The total Cr content in tannery air (1-54 g m ؊3 ) is rather high in comparison to ambient air (4-6 ng m ؊3 ) but the amount of Cr in inhalable particles (Ͻ10 m) is two to three orders of magnitude less (20-60 ng m ؊3 ). The total daily intake of Cr was estimated by the analysis of diet (24.3 ؎ 4.0 g Cr day ؊1 ), drinking water (0.3 ؎ 0.1 g Cr dm ؊3 ) and ambient air. The contribution of the latter was dominant for tannery workers and almost negligible (8%) for the unexposed population.Chromium is an essential nutrient required for sugar and fat metabolism. The normal dietary intake of Cr for the occupationally unexposed population is found to be suboptimal (Ͻ30 g Cr day ؊1 ) whereas tannery workers receive on average 150-325 g of supplemental Cr day ؊1 . Assessment of the Cr status of both populations was made on the basis of the Cr contents of their scalp hair, pre-shift urine and thermally induced sweat. The median Cr contents in these tissues and fluids were significantly higher (PϽ0.01) in tannery workers (hair: 4 g Cr g ؊1 , urine: Cr/creatinine 1.7 g Cr g ؊1 , sweat: 25 g Cr dm ؊3 ) in comparison with the control group (hair: 0.16 g Cr g ؊1 , urine: Cr/creatinine 0.13 g Cr g ؊1 , sweat: 0.7 g Cr dm ؊3 ). Tannery workers absorbed up to 13 times more Cr in comparison to controls, the amount varying considerably depending on the workplace and duration of exposure. The main route of Cr absorption appears to be through the gastrointestinal tract, where medium to large particles play a dominant role. The absorption of Cr from leather dust may be more efficient in comparison to inorganic Cr(III) compounds. Under normal circumstances sweat Cr losses represent at least 20% of urinary Cr excretion.The incidence of glucose intolerance and disturbed lipid metabolism was compared between the unexposed (control) population (n‫)051؍‬ and a population of tannery workers (n‫)831؍‬ from the same residential area.The percentage of glucose-intolerant subjects was significantly (PϽ0.01) lower in the older subgroup (ageϾ48 years), who were even more obese, but not in the whole tannery population in comparison to controls. In the group of subjects displaying glucose intolerance, those from the control population showed a significantly higher body mass index (BMI) of 32.3 and a considerably larger proportion of females (86%) in comparison to subjects from the tannery population (28.2 and 60%, respectively). There was no significant difference in total serum cholesterol levels between the groups. Results of other lipid variables, such as high-density lipid (HDL) cholesterol, low-density lipid (LDL) cholesterol and triglycerides, are controversial: namely, the HDL/LDL ratio was higher for the controls, who showed in contrast significantly higher serum triglyceride levels in comparison to the older subgr...

Longitudinal hair chromium profiles of elderly subjects with normal glucose tolerance and type 2 diabetes mellitus

“…Because impaired glucose tolerance was attributed to compromised Cr body stores, estimation of the Cr status in humans has become a most important task. Determination of Cr in blood [2,9,16,25,27,29 -41], hair [2,34,36,[42][43][44][45][46][47][48][49][50][51][52][53][54][55], and sweat [34,42,43,56] was carried out for that purpose. Changes in plasma Cr (P-Cr) in response to glucose challenge were measured, but the results of different research groups were inconsistent [9,15,27,29,36,57].…”

The Role of Cd40 Ligand in Early Detection of Chromium-Induced Immunotoxic Effects Among Exposed Workers

“…The tanning industrial processes consist of trimming, fleshing, unhairing of hides, followed by bating, pickling, chrome tanning and splitting of hides, and finally stacking, dry milling, buffing, spray finishing and plating [2] . As the tanneries included in the study were all smallsized, it was not possible to divide the exposures according to the industrial processes.…”

Cr (III) genotoxicity and oxidative stress: An occupational health risk for leather tannery workers of South Asian developing countries

“…Cr (VI) is absorbed more readily via sulphate anion channel since its structure is similar to that of the tetrahedral anion (Stupar et al, 1999) while Cr (III), which is octahedral (Shrivastava et al, 2005) and does not readily cross the cell membrane and is not a substrate for active transport (Proctor et al, 2002), but it is thought to reach cells through diffusion or phagocytosis and then solubilized in lysosomes to release Cr3+ ion. Cr that has been absorbed, circulates as free Cr3+, Cr3+ bound to transferrin or other plasma proteins, or complexes like GTF-Cr.…”