Vanadium carbide

Epidemiological data

Administrative data

Endpoint:

epidemiological data

Type of information:

other: Human data

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Publication

Data source

Reference

Reference Type:

publication

Title:

Serum and urinary vanadium of vanadium-exposed workers.

Author:

Kiviluoto, M. et al.

Year:

1979

Bibliographic source:

Scand. j. work environ. & health, 5:362 - 367

Materials and methods

Study type:

longitudinal study

Endpoint addressed:

basic toxicokinetics

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Thorough measurements of vanadium exposure and determinations of serum and urinary vanadium were undertaken.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Divanadium pentaoxide

EC Number:

215-239-8

EC Name:

Divanadium pentaoxide

Cas Number:

1314-62-1

Molecular formula:

V2O5

IUPAC Name:

divanadium pentaoxide

Details on test material:

- Name of test material (as cited in study report): Vanadium pentoxide
No further information on the test material was stated.

Method

Type of population:

occupational

Ethical approval:

not specified

Details on study design:

HYPOTHESIS TESTED:
- In this investigation the environment of vanadium workers was studied.

SETTING:
- This study was undertaken in the vanadium factory of the Otanmäki Mine of the Rautaruukki Comapny, Finland, which has been manufacturing vanadium since 1956.

STUDY POPULATION:
- The subjects of the study were process workers, day workers, repairmen, foremen, and a laboratory worker, 60 men in all.

COMPARISON POPULATION
- Type: reference group
- Details: 24 referents unexposed to vanadium

METHOD OF DATA COLLECTION
Biological sampling:
In order to determine the excretion rate of vanadium, we measured vanadium from successive blood and 18- to 24-h urine samples (8 men) in December 1975. The first blood samples were taken just before the workers left the factory for 3 d rest. The second and third blood samples were taken 18 and 42 h after they had left the factory. The urine samples were taken 0 - 18, 18 - 42 and 42 - 66 h after the beginning of the 3-d rest period.
The serum vanadium levels of all the workers exposed to vanadium (60 men) were examined in March - MAy 1976 at the end of a work shift. At the same time the urine collections for the next 18 h were started to determine the amount of excreted vanadium. In August 1978 the urinary vanadium excretion of the reference group (24 referents unexposed to vanadium) was determined.
The content of vanadium in the urine and serum of the subjects was determined in the Technical Research Center of Finland with an atomic absorption spectrophotometer with a graphite furnace (Perkin-Elmer 503, HGA 72).
The urinary vanadium excretion of the referents was determined in the Oulu Regional Institute of Occupational Health (Perkin-Elmer 603, HGA 74).
No further information on the study design was stated.

Exposure assessment:

measured

Details on exposure:

TYPE OF EXPOSURE:
In the factory, magnetite is roasted with sodium carbonate into pellets. The roasted product is leached, and vanadium is precipitated from the leach liquor as vanadates. The "red cake" thus produced is filtered, washed, and smelted into vanadium pentoxide. Controlling vanadium dust has been very diffcult at the smelting furnances and during the packing of the vanadium pentoxide smelt, the processing of the filtered precipitate, and the grinding of laboratory samples.

TYPE OF EXPOSURE MEASUREMENT:
-Dust sampling: The concentrations of vanadium in the factory air were determined by measurements covering two shifts just before the biological sampling in March-May 1976. The number of samples taken from the breathing zones was 112, and that of the stationary samples 80. The samples were taken by methods commonly used by the Institute of Occupational Health in Finland (Suomen, Standardisoimisliitto. Measurement of dust concentration in workplace air with filter method (SFS 3860). Helsinki 1976, 6 p.; Tossavainen, A. and Kokko, A. Precision and accuracy of foundry dust exposure estimates from air sampling data. Scan. J. Work Environ. & Health (1976): suppl. 1, 13 - 18.)

- Analysis of vanadium: The Millipore filters (type AAWP 03700, pore size 0.8 µm) on which the dust samples were collected were wet ashed with a mixture of nitric acid and hydrochloric acid. The rest was dsisolved in 5% nitirc acid. The vanadium concentrations were determined with an atomic absorption spectrophotometer with a flameless graphite atomizer (Perkin-Elmer 300, HGA 74).The particle size was determined by a modified Andreasen sedimentation method (Öhman, H. and Ödelycke, P. Provtagnings- och analysförfaranden för silikosfarligt damm (Al-rapport no. 3). Arbetsmedicinska Institutet, Stockholm 1968, p. 20) from five dust samples, which were taken separately with a high-volume sampler.
No further information on the exposure was stated.

Statistical methods:

The differences in the urinary excretions and serum levels of vanadium were investigated with the Wilcoxon signed-ranks test. The correlation coefficients between the concentrations of vanadium in factory air, serum, and urine were calculated.

Results and discussion

Results:

EXPOSURE
The mean respirable fraction of the dust (particle size < 5 µm in diameter) was 20% and the range of variations 6 - 32 %. Concentrations exceeding the TLV, 0.5 mg/m^3 (American Conference of Governmental Industrial Hygienists. Threshold limit values for chemical substances and physical agents in the workroom environment with intended changes for 1978. Cincinnati, OH), were found only during the grinding of laboratory samples. Notable concentrations of vanadium were also found during the packing of smelt. These work periods are very short, and the workers wear dust masks. In the other parts of the factory the vanadium concentration was constantly below 0.1 mg/m^3.
In the thorough measurements of the vanadium concentrations in the workroom air and respiratory zones carried out in the vanadium factory, the values measured were 0.01 - 0.04 mg/m^3. These values are considerably lower than corresponding earlier determinations. The concentration of vanadium in the factory air has been measured occasionally in the past. There it can be seen that in the dustiest work areas the total concentration of vanadium in the air exceeded or was equal to the threshold limit value (TLV) of 0.5 mg/m^3 (American conference of governmental industrial hygienists. Threshold limit values for chemical substances and physical agents in the workroom environment with intended changes for 1978. Cincinnati, OH).

FINDINGS
The mean urinary 18-h vanadium excretion of the exposed workers was 0.26 µmol. The concentration of vanadium in the urine of the referents was below 0.04 µmol/l, which was the sensitivity of the vanadium assay. Therefore, the concentration vanadium in serum of the referents was not measured. The mean vanadium concentration in the serum of the exposed workers was 0.2 µmol/l.
No correlation was found between the vanadium concentration in the factory air and the serum level and the urinary excretion of vanadium.
In higher vanadium exposure (0.2 - 0.5 mg/m^3) the vanadium concentration in the air inhaled remaining unknown due to use of dust masks - the urinary vanadium excretion and serum vanadium level decreased significantly with exposure-free time.
No correlation was found between a low vanadium concentration (0.01 - 0.04 mg/m^3) in air and serum and the urinary excretion.

Applicant's summary and conclusion

Conclusions:

The mean urinary 18-h vanadium excretion of the exposed workers was 0.26 µmol. The concentration of vanadium in the urine of the referents was below 0.04 µmol/l, which was the sensitivity of the vanadium assay. Therefore, the concentration vanadium in serum of the referents was not measured. The mean vanadium concentration in the serum of the exposed workers was 0.2 µmol/l.
No correlation was found between the vanadium concentration in the factory air and the serum level and the urinary excretion of vanadium.
In higher vanadium exposure (0.2 - 0.5 mg/m^3) the vanadium concentration in the air inhaled remaining unknown due to use of dust masks - the urinary vanadium excretion and serum vanadium level decreased significantly with exposure-free time.
No correlation was found between a low vanadium concentration (0.01 - 0.04 mg/m^3) in air and serum and the urinary excretion.