Residues (petroleum), hydrodesulfurized vacuum

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Full experimental details are not provided in the published paper

Justification for type of information:

The standard OECD 471 test is not suitable to test petroleum UVCBs, because it has a tendency to produce false negatives for these substances. Therefore, the petroleum industry has developed a Modified Ames assay, optimized to accurately identify positive results for this endpoint. This deviation from the prescribed testing procedure requires some further explanation which is given in the attached document. The document gives a brief history of the development of the Modified Ames test and outlines Concawe’s proposed work (as part of a wider testing strategy, see Annex 13) to further support the use of this test for PS.

Data source

Reference

Reference Type:

publication

Title:

Generation of bitumen fumes using two fume generation protocols and comparison to worker industrial hygiene exposures.

Author:

Kriech, A., Osborn, L., Wissel, H., Redman, A. Smith, L., Dobbs, T.

Year:

2007

Bibliographic source:

J Occup and Environ Hyg 4 (81) 6-19

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

other: ASTM Standard Method E 1687-04

Principles of method if other than guideline:

Modified Ames assay based on method described by Blackburn et al., 1986 and standardised as ASTM Standard Method E 1687-95 (ASTM, Philadelphia, PA, 1995). Enhanced method to detect PAH mediated mutagenic activity

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

8052-42-4

Cas Number:

8052-42-4

IUPAC Name:

8052-42-4

Constituent 2

Reference substance name:

Condensate of paving bitumen fumes.

IUPAC Name:

Condensate of paving bitumen fumes.

Test material form:

other: low viscosity liquid hydrocarbon

Details on test material:

Four fume samples generated from tank headspaces containing paving bitumen
Distillation range, fluorescence and PAH content described in the attachment

Method

Species / strain

Species / strain / cell type:

S. typhimurium TA 98

Metabolic activation:

with and without

Metabolic activation system:

S-9 microsomal activation mixture

Test concentrations with justification for top dose:

Doses equivalent or similar to ASTM Standard Method E1687-04

Evaluation criteria:

Test criteria as follows:
MI greater than or equal to 1.0 = positive
MI less than 1.0 = negative

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Remarks:

MI 0.89 (TP-A sample)

Cytotoxicity / choice of top concentrations:

not specified

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Remarks:

MI 0.98 (TP-B sample)

Cytotoxicity / choice of top concentrations:

not specified

Positive controls validity:

valid

Test results 3

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

positive

Remarks:

MI 1.0 (TP-C sample)

Cytotoxicity / choice of top concentrations:

not specified

Positive controls validity:

valid

Test results 4

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Remarks:

MI 0.69 (TP-D sample)

Cytotoxicity / choice of top concentrations:

not specified

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

Not mutagenic

Executive summary:

Samples of four paving fume condensates, collected form the headspace of heated storage tanks, were tested in a modifed Ames assay according to ASTM Standard Method E1687 -04. This method has been enhanced to detect PAH mediated mtagenic activity in petroleum substances.

Four samples were tested in S. typhimurium TA 98, with and without metabolic activation. Three samples were clearly negative (MI values < 1.0). The remaining sample was marginally positive with an MI value of 1.0.