Chromium trioxide

Direct observations: clinical cases, poisoning incidents and other

Administrative data

Endpoint:

direct observations: clinical cases, poisoning incidents and other

Type of information:

other: Occupational exposure study

Adequacy of study:

key study

Study period:

FEB 1984 to MAY 1984

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

publication

Title:

Occupational dermatosis among chrome platers

Author:

Lee, H.S. and Goh, C.L.

Year:

1988

Bibliographic source:

Contact Dermatitis 1988:18: 89-93

Materials and methods

Study type:

other: Occupational exposure study

Endpoint addressed:

skin irritation / corrosion

eye irritation

respiratory irritation

skin sensitisation

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Factories engaged in chrome plating for at least 5 8-h working days a week were included in the study.
Subjects: Chrome platers, who operate and maintain the chrome plating bath or tank; control subjects: workers not chrome plating in the same factories were similarly examined
Parameter: Their age, race, sex and duration of employment in chrome plating were noted. Muco-cutaneous symptoms (of the last year), examination of skin disease, patch test to potassium dichromate 0.5% when ulcers or dermatitis were noted.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Chromic acid

EC Number:

231-801-5

EC Name:

Chromic acid

Cas Number:

7738-94-5

Molecular formula:

CrH2O4

IUPAC Name:

dihydroxy(dioxo)chromium

Specific details on test material used for the study:

All practical chrome plating is done from a solution consisting mainly of hexavalent chromic acid plus small but critical quantities of sulphuric acid or a complex fluoride (catalyst). The chromic acid concentration in the plating bath is usually maintained between 250 g/L and 400 g/L The weight ratio of chromic acid to sulphuric acid is usually 100:1.

Method

Type of population:

occupational

Subjects:

- Number of subjects exposed: 37 male chrome platers and 37 male control subjects were interviewed and examined.
- Sex: Male
- Age: The mean age of the chrome platers was 31.3 (standard deviation [SD] +/- 8.6) years (range 17 to 53 years). 81% were between 20 and 40 years old. Controls were machted for sex, age and race. Age was matched to within 5 years of the exposed subjects. The mean age was 31.2 (SD +/- 8.4) (range 18 to 51 years).
- Race: 84% of the chrome platers (19 bright chrome platers, 12 hard chrome platers) were Chinese; 11% (4 hard chrome platers) Malays and 6% (2 hard chrome platers) were Indians.
- Demographic information:
- Known diseases:
- Other: The duration of employment as chrome platers was 8.1 (SD +/-7.9) years (range 3 weeks to 30 years). 44% of the hard chrome platers had been thus employed for > 10 years compared with only 21 % of the bright chrome platers

Ethical approval:

not applicable

Route of exposure:

dermal

inhalation

Reason of exposure:

unintentional, occupational

Exposure assessment:

not specified

Details on exposure:

Electrolysis produces bubbles of oxygen and hydrogen that generate chromic acid mist or spray by bursting violently at the surface of the liquid.
There are 2 types of chrome plating, depending on the purpose for which plating is required. A significant difference of exposure to airborne chromate in the 2 types of plating was demonstrated before. They recommended that a distinction should always be made between the 2 types of chrome plating in studies of chromate exposures among electroplaters:
Bright chrom plating: A thin coat of chromium (usually <0.75 µm) is electrodeposited onto a substrate (metal or plastic) to provide a durable, non-tarnishing surface for a decorative purpose (widespread use).
Hard chrome plating: The layer of chromium required is thicker. The purpose is to obtain a surface which is resistant to heat, wear, corrosion, and has a low coefficient of friction.
Exposure to airborne chromate is generally higher in hard chrome plating than in bright chrome plating.
The basic manufacturing process may be summarized as follows: raw material >>preplating >>plating >>postplating >>product.
The article to be plated (raw material) is usually a metal (iron or steel) or a plastic. It is pretreated (preplating) to clean the surface, so that good adhesion can be obtained between the article and the electro-deposit. It involves degreasing with solvent and cleansing with alkali and acid.
The article is then plated by introducing it into the plating solution (plating) and switching the current on. In bright chrome plating, nickel plating is done prior to chrome plating.
After plating (postplating), the article is taken out of the bath and rinsed with water and dried. It is then sent to another section for assembly or packaging.

Examinations:

All workers who came under the definition as "chrome plater" were studied. Their age, race, sex and duration of employment in chrome plating were noted. Muco-cutaneous symptoms experienced over the last 1 year were recorded. They were then examined for skin disease. A patch test (carried out by the standard method) to potassium dichromate 0.5% pet was performed when ulcers or dermatitis were noted.

Medical treatment:

none

Results and discussion

Clinical signs:

The rate of mucosal symptoms was 57% (21/37). Symptoms were significantly more common in the exposed group as compared to controls (p< 0.001 for each of the symptoms). The prevalence of symptoms of throat irritation, nasal irritation, and rhinorrhoea was significantly higher in the hard chrome group than in the bright chrome group. 14 (38%) had skin lesions. 7 workers had skin ulcers, 6 had dermatitis and 1 had ulceration and dermatitis. Another 16 (43%) had scars of previous ulcers. The prevalence of ulcers and scars was higher in the exposed group than controls. The prevalence of dermatitis was not significantly different between the exposed and controls. There was no significant difference in the prevalence of skin ulcers and scars between the hard and bright chrome platers. 1 worker had a nasal septum perforation. He was asymptomatic.
63% of the lesions occurred on the hands, fingers and wrists. Ulcers were seen in 3 hard chrome platers, and 5 bright chrome platers.
Of 7 workers with ulcers, only 1 was allergic to chromate. Of the 6 workers with dermatitis, 2 were allergic to chromate. The worker with ulceration and dermatitis was not allergic to chromate.

Any other information on results incl. tables

Prevalence of mucosal symptoms among 37 chrome platers compared to controls

Symptoms	No. of workers exposed		Significance* hard vs. bright	Exposed total	Controls	Significance* exposed vs. control
	hard	bright
throat irritation	14 (77.7%)	4 (21.1%)	p= 0.0009	18 (48.6%)	2 (5.4%)	p =0.0001
nasal irritation	12 (66.7%)	3 (15.8%)	p =0.0020	15 (40.5%)	2 (5.4%)	p =0.0006
rhinorrhoea	9 (50%)	3 (15.8%)	p= 0.0234	12 (32.4%)	0	p= 0.0004
nose bleed	1 (5.6%)	1 (5.2%)	p =0.7432	2 (5.4%)	0	p =0.2466
eye irritation	3 (16.7%)	2 (10.5%)	p= 0.8470	5 (13.5%)	1 (2.7%)	p =0.0996
total	18 (100%)	19 (100%)		37 (100%)	37 (100%)

  * Test of significance by Fisher's exact test when the expected number per cell <5. Otherwise the X² test with Yate's correction was used.

Prevalence of cutaneous signs among 37 chrome platers compared to controls

Symptoms	No. of workers exposed		Significance* hard vs. bright	Exposed total	Controls	Significance* exposed vs. control
	hard	bright
Skin ulcer	3 (16.7%)	5 (26.3%)	p= 0.3787	8 (21.6%)	0
Scar of ulcer	6 (33.3%)	10 (52.6%)	p= 0.2160	16 (43.2%)	0
Eczema	3 (16.7%)	4(21.1%)	p= 0.5928	7 (18.9%)	3 (8.1%)	p= 0.1574
Nasal septum perforation	0	1 (5.2%)		1 (2.7%)	0
total	18 (100%)	19 (100%)		37 (100%)	37 (100%)

* Test of significance by Fisher's exact test when the expected number per cell <5. Otherwise the X² test with Yate's correction was used.

Distribution of cutaneous lesions by anatomical site among 37 chrome platers

Site	Frequency
	ulcer	eczema	total
hands, fingers, wrist	8	4	12 (63.2%)
forearms	3	1	4 (21.1 %)
legs	0	2	2 (10.5 %)
abdomen	0	1	1 (5.3 %)
total	11	8	19 (100%)

Applicant's summary and conclusion

Conclusions:

Overall, mucosal symptoms in chrome platers included throat and nasal irritation, rhinorrhoea, nose bleed and eye irritation; cutaneous signs consisted of skin ulcer, scar of ulcer, eczema and nasal septum perforation.

Executive summary:

The study was conducted between February and May 1984. Only factories engaged in chrome plating for at least 5 8-h working days a week were included in the study. On the basis of frequency of exposure to chromium, 17 plants were selected for the study. 37 male chrome platers and 37 male control subjects were interviewed and examined. Muco-cutaneous symptoms experienced over the last 1 year were recorded. They were then examined for skin disease. A patch test (carried out by the standard method) to potassium dichromate 0.5% pet. was performed when ulcers or dermatitis were noted.

14 (38%) of 37 chrome platers in 17 chrome electroplating factories surveyed had occupational contact dermatitis, chrome ulcers, or both. 7 had chrome ulcers, 6 had contact dermatitis and 1 had both. Another 16 (43%) workers had scars suggestive of previous chrome ulcers. Mucosal irritation was present in 57% of the workers. The most common was throat irritation (49%) followed by nasal irritation (41%). Mucosal irritation was more common in hard chrome platers, while skin ulcers and dermatitis were more common in bright chrome platers. Nasal septum perforation was seen in 1 worker. Skin ulceration appeared to be a more specific sign for occupational dermatosis in chrome platers than dermatitis when the prevalence rates were compared to controls. Of the 7 workers with chrome ulcers, only 1 was allergic to chromate. Of the 6 workers with dermatitis, 2 were allergic to chromate. The worker with ulceration and dermatitis was negative to chromate and nickel. Irritant factors are therefore important in the aetiology of contact dermatitis in these chrome platers.

 

Overall, mucosal symptoms in chrome platers included throat and nasal irritation, rhinorrhoea, nose bleed and eye irritation; cutaneous signs consisted of skin ulcer, scar of ulcer, eczema and nasal septum perforation.