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Administrative data

Endpoint:
health surveillance data
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
Not Reported
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Meets generally accepted scientific standards, well documented and acceptable for assessment
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
publication
Title:
Urinary elimination of nickel and cobalt in relation to airborne nickel and cobalt exposures in a battery plant
Author:
Yokota K, Johyama Y, Kunitani Y, Michitsuji H, Yamada S
Year:
2007
Bibliographic source:
Int Arch Occup Environ Health. 80: 527-531

Materials and methods

Study type:
biological exposure monitoring
Endpoint addressed:
basic toxicokinetics
Test guideline
Qualifier:
no guideline available
Principles of method if other than guideline:
The relationship between nickel concentrations in the ambient air and in the urine were determined in workers at a battery plant using nickel hydroxide.
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): nickel hydroxide, Ni(OH)2
- Composition of test material, percentage of components: Anode materials contained 200kg by weight of nickel hydroxide, recycled nickel powder 18kg, metallic cobalt 10kg, and cobale oxyhydroxide 10 kg. According to the manufacturer, the commerical Ni(OH)2 powder of specific particle diameter (9-12 uM) contained 97.2 % nickel hydroxide and 2.8 % cobalt hydroxide.

Method

Type of population:
occupational
Ethical approval:
other: confirmed, informed consent obtained
Details on study design:
OBJECTIVE: estimate the relationship between Ni concentrations in the ambient air and in the urine at a battery plant using nickel hydroxide

SUBJECTS
- Survey was conducted in the second half of a working week at a plant manufacturing nickel-hydroxide batteries. Workers were exposed to a mixture of metallic cobalt, cobalt, oxyhydroxide and nickel hydroxide dust.
- 16 male workers participated in the study (mean age = 39 years, mean employment = 3.5 years)
- Workers wore disposable dust masks

AIR SAMPLING AND ANALYSIS
- Personal air samplers (battery-operated pump, PAS-500) were used to collect breathing zone samples for two consecutive workdays (at least 9 hours/day) from each worker
- Air was aspirated at a flow rate of 200 ml/min
- Ni and Co in total airborne dust were analyzed after wet digestion by inductively coupled plasma absorption emission spectrophotometry (ICP-AES) (detection limits were 10 ppb Ni and 5 ppb Co)

URINE SAMPLING AND ANALYSIS
- Each worker provided two urine samples per day (one in the morning and one in the afternoon after the work shift) for two consecutive days
- Samples were collected in decontaminated polyethylene bottles with screw caps and stored at -20ºC until analysis.
- Ni and Co concentrations were determined by direct injection (diluted with water) onto an electro-thermal atomic absorption spectrometer with a graphite atomizer calibrated with urine-matched standard solutions.
- Urine concentrations were corrected for specific gravity (1.024)

STATISTICS
- Student’s paired t-test and regression analysis were employed as necessary

Results and discussion

Results:
CLINICIAL OBSERVATIONS
- Two workers had skin itching and one had an itchy red rash on the hands

AIR AND URINE CORRELATIONS
- A linear correlation was observed between time-weighted average (TWA) concentrations of Ni and Co in the air: TWA concentrations of Co varied between 0.004 and 0.330 (mean 0.067) mg/m3, Ni ranged from 0.018 to 2.376 (mean 0.481) mg/m3. Subjects were exposed to higher levels of Ni than Co: Ni (mg/m3) = -0.02 + 7.41 Co (mg/m3), r=0.272
- There were no statistical differences between pre- and post-shift urine samples except for urinary Co concentrations on the first day.
- No correlation was found between Ni in the air and in post-shift urine.
Day 1, Pre Shift: 17.5 +/- 10.7 (5.0-39) ug Ni/l
Day 1, Post Shift: 21.5 +/- 17.4 (5.0-67.5) ug Ni/l
Day 2, Pre Shift: 20.1 +/- 13.1 (6.3-39.4) ug Ni/l
Day 2, Post Shift: 20.9 +/- 16.7 (4.7-52.9) ug Ni/l
- A good correlation was found between Co and Ni in post-shift urine: Ni (ug/ml) = 9.9 + 0.343 Co (ug/ml), r= 0.833.

Any other information on results incl. tables

Not Applicable

Applicant's summary and conclusion

Conclusions:
The authors concluded that they were unable to find a correlation between external and internal Ni exposure. The lack of correlation between air and urinary concentrations may be explained by the use of respiratory protection by the plant workers. In conclusion, results suggest that exposure to nickel hydroxide yields lower urine nickel concentrations than the very soluble nickel salts, and that the grouping of nickel hydroxide might be reevaluated.
Executive summary:

Yokota et al., (2007) conducted an evaluation in workers occupationally exposed to a mixture of metallic cobalt, cobalt oxyhydroxide and nickel hydroxide dust in an effort to estimate the relationship between Ni concentrations in the ambient air and in the urine at a battery plant using nickel hydroxide. The survey was conducted in 16 male workers (mean age = 39 years, mean employment = 3.5 years); personal air was monitored and urine samples collected for two consecutive days from each worker. Correlations of total nickel and cobalt were then evaluated. A linear correlation was observed between the higher levels of nickel relative to cobalt [Ni (mg/m3) = -0.02 + 7.41 Co (m/m3), r=0.272]. There were no statistical differences between pre- and post-shift urine samples except for urinary Co concentrations on the first day. No correlation was found between Ni in the air and in post-shift urine, though a good correlation was found between Co and Ni in post-shift urine: Ni (µg/ml) = 9.9 + 0.343 Co (µg/ml), r= 0.833. The authors concluded that they were unable to find a correlation between external and internal Ni exposure. The lack of correlation between air and urinary concentrations may be explained by the use of respiratory protection by the plant workers. In conclusion, results suggest that exposure to nickel hydroxide yielded lower urine nickel concentrations than the very soluble nickel salts, and that the solubility grouping of nickel hydroxide might be reevaluated. STUDY RATED BY AN INDEPENDENT REVIEWER