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Administrative data

Endpoint:
epidemiological data
Type of information:
other: Review
Adequacy of study:
weight of evidence
Study period:
Variable
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Reviews of epidemiological evidence are presented.

Data source

Referenceopen allclose all

Reference Type:
review article or handbook
Title:
Health risk assessment report for metallic chromium and trivalent chromium
Author:
Finnish Institute of Occupational Health
Year:
2006
Bibliographic source:
Published by the International Chromium Development Association
Reference Type:
review article or handbook
Title:
Toxicological profile for chromium
Author:
Agency for Toxic Substances and Disease Registry
Year:
2000
Bibliographic source:
US Dept of Health and Human Services, Public Health Service, ATSDR
Reference Type:
review article or handbook
Title:
The toxicity of chromium and inorganic chromium compounds
Author:
Health and Safety Executive
Year:
1989
Bibliographic source:
HSE Toxicity review 21

Materials and methods

Study type:
other: Various epidemiology studies are summarized.
Endpoint addressed:
carcinogenicity
Test guideline
Qualifier:
no guideline available
Deviations:
not applicable
Principles of method if other than guideline:
The reviews include studies of various designs.
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
Chromium hydroxide sulphate
EC Number:
235-595-8
EC Name:
Chromium hydroxide sulphate
Cas Number:
12336-95-7
Molecular formula:
CrHO5S
IUPAC Name:
chromium hydroxide sulphate
Constituent 2
Reference substance name:
Chromium (III) compounds
IUPAC Name:
Chromium (III) compounds
Details on test material:
Most studies reviewed include exposures to chromium (III) with possible concomitant exposure to definite or suspected carcinogens.

Method

Type of population:
occupational
Details on study design:
Evidence from a number of case reports and epidemiological studies among tannery workers were reviewed.

Results and discussion

Results:
The importance of valency states and water solubility of chromium compounds for carcinogenic potential was evaluated based on evidence from old and recent case reports and epidemiological studies among chromate workers. It was concluded that no evidence has been presented indicating that human exposure to chromium (III) is associated with increased cancer risk (FIOH, 2006). A mortality study was conducted with with two groups of British tanners. One group consisted of 573 men who made leather tanned by vegetable extracts. The other group consisted of 260 men who used chrome tanning to make leather. The follow-up extended from 1939 until 1982 with no significant excesses of deaths reported for any of the common sites of cancer in either group of workers (FIOH, 2006). These findings were similar to another study in the mortality of a cohort of 9365 chrome leather tannery workers were studied retrospectively. This study revealed some elevated risks for certain causes of death among tannery workers but no significantly increased risks were noted for any cause of death thought a priori to be occupationally related. No excess of cancers were noted in another mortality study of 2926 male workers at tanneries in the "leather" area of Tuscany in Italy. Slight but statistically non-significant increases were seen in cancers of the lung, bladder, kidney, pancreas and leukemia. The authors noted that results from this study were inconclusive due to exposure to multiple carcinogens. A review of epidemiological studies on occupational cancer risk in the tanning, leather and shoe industries confirmed the high risk of nasal cancer related to exposure to leather dust (FIOH, 2006). Studies of workers in tanneries, where exposure is mainly to water-soluble trivalent chromium, in the US (0.002 -0.054 mg total Cr/m3), the United Kingdom, and the Federal Republic of Germany reported no association between exposure to Cr (III) and excess risk of cancer (ATSDR, 2000). The vital status of 260 men making chrome-tanned leather in two UK tanneries was ascertained in 1982 and follow-up was 94% complete. Cause-specific mortality within the cohort was compared with national statistics for males. One hundred and forty-four deaths occurred, 126.8 being expected. There was no evidence of any excess mortality from cancers of the lung, gastrointestinal tract, prostate or "all other sites" (HSE, 1989). Another study focused on mortality among employees at two West German plants, one producing chromium (III) oxide and the other chromium (III) sulphate for use in leather tanning. Nineteen deaths among all chromium oxide workers and 13 deaths among chromium sulphate workers were analysed from workers having at least five years' work experience at the plant. No significant Cr (III)-related findings were revealed although the study was poorly reported. Workers at the chromium sulphate plant were also exposed to Cr (VI) (HSE, 1989).

Applicant's summary and conclusion

Conclusions:
The evaluations of the potential carcinogencity of trivalent chromium by international and national agencies and individual scientists are unanimous that the evidence of carcinogenicity is inadequate in humans.
Executive summary:

A review of the available epidemiological evidence consisted mainly of studies in leather tanners, who are exposed to Cr (III), and were consistently negative. For some leather tannery workers, increased risks have been reported, but almost invariably in the epidemiological studies, the available data do not permit discrimination between simultaneous exposure to trivalent chromium and hexavalent chromium. There is fairly general agreement that the hexavalent species increases the risk of lung cancer and sinonasal cancer and that the trivalent species does not. For cancers other than those of the lungs and sinonasal cavity, no consistent pattern of cancer risk has been demonstrated in workers exposed to chromium compounds.

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