Hexachloroplatinic acid

Sensitisation data (human)

Administrative data

Endpoint:

sensitisation data (humans)

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: data are scientifically acceptable

Data source

Reference

Reference Type:

publication

Title:

Occupational hypersensitivity to metal salts, including platinum, in the secondary industry

Author:

Cristaudo A et al.

Year:

2005

Bibliographic source:

Allergy, 60, 159-164

Materials and methods

Type of sensitisation studied:

respiratory

skin

Study type:

survey

Test guideline

Qualifier:

no guideline required

Principles of method if other than guideline:

Occupational exposure to platinum salts;
skin prick and patch testing with hexachloroplatinic acid and sodium hexachloroplatinate, each at >99.2% purity, to determine the prevalence and clinical characteristics of hypersensitivity among 153 workers in a catalyst production plant

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Hexachloroplatinic acid

EC Number:

241-010-7

EC Name:

Hexachloroplatinic acid

Cas Number:

16941-12-1

Molecular formula:

Cl6Pt.2H

IUPAC Name:

platinum(4+) dihydrogen hexachloride

Details on test material:

Hexachloroplatinic acid
CAS# 16941-12-1

Sodium hexachloroplatinate
CAS# 16923-58-3

Method

Type of population:

occupational

Subjects:

Workers in a catalyst production plant where different types of production activities were carried out involving solubilizing "platinum metals" in closed reactors. The resulting solutions were used to produce intermediates (dust, granules, pellets, beads) and finished products (catalysts for transport and domestic electrical appliances) through impregnation of different substrates and calcination in kilns. Additionally precious metals were refined from exhaust catalysts after a combustion cycle. Various jobs in the plant resulted in exposure to platinum classified into 3 levels:
- production of platinum salts, solution and refining (high exposure)
- all other production workers (low exposure)
- office workers outside the production area (no exposure)

153 employees examined

137 men, 16 women
Mean age 34 years (range 21-60 years)

Controls:

11 of the 153 employees were unexposed office workers

Details on study design:

Cross-sectional study

Work exposure and medical questionnaire

Physical examination

Skin prick tests with platinum group elements (PGEs: aqueous solutions of hexachloroplatinic acid (0.01-0.00000001 M), potassium tetrachloroplatinate (0.01-0.00000001 M), sodium hexachloroplatinate (0.01-0.00000001 M), iridium chloride (0.001-0.000001 M), rhodium chloride (0.001-0.000001 M) and palladium chloride (0.001-0.000001 M)); also 16 common aeroallergens (to determine atopy); readings at 25 minutes.

Patch tests with PGEs (15 ul of aqueous solutions of hexachloroplatinic acid (0.01 M), potassium tetrachloroplatinate (0.01 M), sodium hexachloroplatinate (0.01 M), iridium chloride (0.001 M), rhodium chloride (0.001 M) and palladium chloride (0.01 M)); readings at day 2 (unless subject had urticaria, in which case 25 min)

Data on health history, previous work exposure to platinum salts and other hazardous substances, smoking, duration of employment, job description.

Duration of employment, mean (+/- SD) 103.9 (+/- 98.5) months, range 1-360 months, median 84 months.

3 exposure categories:
high exposure (n=37)
low exposure (n=105)
no exposure (n=11)

Results and discussion

Results of examinations:

Skin prick tests with platinum salts gave positive responses in 22/153 workers (14%): 8 reacted to all 3 platinum salts tested, 4 to both hexachloroplatinic acid and potassium tetrachloroplatinate, 3 to both hexachloroplatinic acid and sodium hexachloroplatinate, 7 to hexachloroplatinic acid only

Of the 22 workers with positive skin prick tests to hexachloroplatinic acid, 1 also had a positive patch test; 1 further individual with a negative skin prick test to hexachloroplatinic acid had a positive patch test

Of the total of 23 workers with a skin reaction to hexachloroplatinic acid, incidences were 0/11 (0%), 14/105 (13%) and 9/37 (24%) in the no, low and high exposure groups respectively; the adjusted prevalence odds ratio for the high exposure group (compared with the low exposure group) was 2.4 (95% confidence limits 0.8-6.9). Incidences were 7/72 (10%) and 16/70 (23%) in those employed for 0-5 and 6-30 years respectively; adjusted prevalence odds ratio 3.2 (95% CI 1.2-8.9)

Clinical characteristics of the 23 workers with positive skin responses to hexachloroplatinic acid included rhinitis (n=1), asthma (n=10), urticaria (n=5) and eczema (n=2) [some subjects had more than one symptom; results not presented in relation to
exposure level]

"Descriptive analysis demonstrates that asthma and urticaria are more frequent in subjects allergic to Pt-salts, while rhinitis and dermatitis commonly belong to allergies of common inhalants as well as allergies to Pt-salts."

Applicant's summary and conclusion

Conclusions:

"[Platinum] salts and especially [hexachloroplatinic acid] are relevant allergens in catalyst production plants and... both the hypersensitivity and clinical manifestation are associated with high levels of exposure." "[Platinum] salts are important allegens in the catalyst industry and... the clinical manifestations involve both the respiratory system and the skin. Hexachloroplatinic acid should be considered the most important salt to use for skin prick tests."

Executive summary:

The study was designed to determine the prevelance and clinical characteristics of hypersensitivity to Pt-salts and other Pt-group elements (Pd, Rh, Ir) among exposed workers in a catalyst production plant. A total of 153 subjects working in a catalyst manufacturing and recycling factory were examined - consisting of a work exposure and medical questionnaire, physical examination, skin prick tests for platinum group elements (PGE) and other common aeroallergens, and patch tests for PGEs. Skin prick tests and patch tests were performed with hexachloroplatinic acid, potassium tetrachloroplatinate, sodium hexachloroplatinate, iridium chloride, rhodium chloride and palladium chloride. Positive prick test reactions to Pt-salts at various concentrations were found in 22 (14.4%) of 153 workers; eight had simultaneous reactions to all Pt-salts tested; seven had positive responses to hexachloroplatinic acid only; four had simultaneous positive reactions to both hexachloroplatinic acid and potassium tetrachloroplatinate; three had positive reactions to hexachloroplatinic acid and sodium hexachloroplatinate. Three of 22 had positive reactions to hexachloroplatinic acid and iridium chloride solutions, two of these had positive reactions to hexachloroplatinic acid, iridium chloride and rhodium chloride solutions. Positive patch test reactions to platinum salts at day 2 were seen in two of 153 subjects. The investigators concluded that Pt-salts are important allergens in the catalyst industry and that the clinical manifestations involve both the respiratory system and the skin.