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Exposure related observations in humans: other data

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exposure-related observations in humans: other data
Type of information:
experimental study
Adequacy of study:
supporting study
other: human occupational monitoring study
Rationale for reliability incl. deficiencies:
other: No clear guideline. Not GLP. Results only positive after metabolic activation and in concentrated urine. Confounding exposure to diesel exhaust and possibly coal-tar

Data source

Reference Type:
Urinary excretion of mutagens, thioethers and D-glucaric acid in workers exposed to bitumen fumes
Pasquini et al
Bibliographic source:
Int Arch Occup Environ Health (1989) 61:335-340

Materials and methods

Type of study / information:
Occupational study of 17 workers exposed to fumes from hot bitumen paving operations. Genotoxicity was evaluated by undertaking Ames assays on concentrated urine. Results compared to group of 27 unexposed workers.
Endpoint addressed:
genetic toxicity
Principles of method if other than guideline:
Workplace worker health survey. Environmental exposure monitoring to fumes and PAH (BaP) content of the fumes and substance. Urinary mutagenicity in concentrated urine was tested using Ames TA98 and TA 100 w & w/o arachlor-S9 and after treatment with beta-glucoronidase, and by measuring urinary thioethers and urinary D-glucaric acid.
GLP compliance:
(not required)

Test material

Constituent 1
Reference substance name:
most likely 8052-42-4
most likely 8052-42-4
Constituent 2
Reference substance name:
Emissions from hot bitumen
Emissions from hot bitumen


Ethical approval:
not specified
Details on study design:
The study group consisted of 17 males employed in road bituminization (5 drivers and 12 level wheel operators). Environmental monitoring was done on bitumen fumes and the substance - both turned out non mutagenic. Results were compared to 27 non-occupationally exposed male office clerks who were matched with the exposed group for age, smoking habits and alcohol consumption. Subjects under medication were avoided. Results were analysed after dividing them into four groups (smoking exposed/unexposed and non-smoking exposed/unexposed) to analyze the contribution of smoking and bitumen exposure to the urinary parameters.
Details on exposure:
Workplace eXposure to emissions from hot bitumen. Possible co-exposure to coal tar and diesel exhaust.

Environmental monitoring (no further information provided)

Results and discussion

Bitumen samples contained low levels of total PAH and were not mutagenic by the Ames test. Urinary mutagenicity was detectable only with the TA98 strain and only with metabolic activation (+S9). Further addition of beta-glucuronidase did not enhance mutagenicity. The other two parameters (urinary thioesters and D-glucaric acid) were not affected by bitumen exposure. The number of individuals with mutagenic urine was greater in the exposed compared to the non-exposed group.

Applicant's summary and conclusion

The number of individuals with mutagenic urine was higher in exposed than in non-exposed groups. However, workers were co-exposed to diesel exhaust (and possibly coal-tar) and urine -which was concentrated prior to measurement- was only mutagenic in one strain and only after metabolic activation.
Executive summary:

The study investigated a small group (17) of paving workers exposed to bitumen, which contained low level PAH and turned out not mutagenic by Ames test. Urine was tested for mutagenicity by Ames test, D-glucaric acid and urinary thio-esters. Mutagenic urine was higher in exposed compared to non-exposed individuals only in the Ames test, one strain, and after metabolic activation. Workers are co-exposed to diesel exhaust and possibly coal tar, which limits the usefulness of the study.