Styrene

Exposure related observations in humans: other data

Administrative data

Endpoint:

exposure-related observations in humans: other data

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: acceptable, well-documented publication/report meeting basic scientific principles; small group size

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Evaluation of Long-Term Occupational Exposure to Styrene Vapor on Olfactory Function

Author:

Dalton, P. et al.

Year:

2007

Bibliographic source:

Chem. Senses 32: 739-747

Reference 2

Reference Type:

review article or handbook

Title:

European risk assessment report, Styrene CAS No. 100-42-5, EINECS No. 202-851-5, Draft for submission to SCHER, November 2007.

Author:

European Union

Year:

2007

Bibliographic source:

Styrene CAS No. 100-42-5, EINECS No. 202-851-5, Draft for submission to SCHER, November 2007

Materials and methods

Type of study / information:

Investigation whether occupational exposure to styrene is associated with olfactory impairment

Endpoint addressed:

neurotoxicity

Principles of method if other than guideline:

Multiple measures of olfactory function were evaluated using a standardized battery of clinical assessments from the Monell-Jefferson ChemosensoryClinical Research Center including odor identification ability.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Styrene

EC Number:

202-851-5

EC Name:

Styrene

Cas Number:

100-42-5

Molecular formula:

C8H8

IUPAC Name:

ethenylbenzene

Details on test material:

- Name of test material (as cited in study report): styrene
- Analytical purity: no data

Method

Details on study design:

Olfactory function was measured in two groups: workers in a German reinforced-plastics boat-maufacturing facility having a minimum of 2 years of styrene exposure (15-25 ppm as calculated from urinary metabolite concentrations, with historical exposures up to 85 ppm) and a group of age-matched workers from the same facility with lower styrene exposures. The results were also compared with normative data previously collected from healthy, unexposed individuals. Thresholds for styrene were also obtained as a measure of occupational olfactory adaptation. Styrene exposure history was calculated through the use of past biological monitoring results for urinary metabolites of styrene; current exposure was determined for each individual using passive air sampling for styrene and biological monitoring for styrene urinary metabolites (mandelic acid [MA] + phenylglyoxylic acid [PGA]). For both current and historic exposures, the results of the biological monitoring were entered into a previously developed regression model (Lees et al., 2003) to calculate the corresponding respiratory exposure.

Exposure assessment:

measured

Results and discussion

Results:

Current mean effective styrene exposure during the day of olfactory testing for the group of workers who worked directly with styrene resins was 18 ppm styrene (SD=14), 371 g/g creatinine MA + PGA (SD=289) and that of the group of workers with lower exposures was 4.8 ppm (SD=5.2), 93 g/g creatinine MA + PGA (SD=100). Historic annual average exposures for all workers with lower exposures were greater by a factor of up to 6x.
No differences unequivocally attributable to exposure status were observed between the Exposed and Comparison groups or between performance of either group and normative population values on thresholds for odor identification. Although odor identification performance was lower among workers with higher ongoing exposures, performance on this test is not a pure measure of olfactory ability and is influenced by familiarity with the stimuli and their sources. Consistent with exposure-induced sensory adaptation, however, elevated styrene thresholds were significantly associated with higher occupational exposures to styrene.