Slack wax (petroleum), clay-treated

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

1985-11-05 to 1987-01-26

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This study is classified as reliable without restriction because it was conducted according to or similar to guideline study OECD TG 473, without exceptions.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1987

Report date:

1987

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)

GLP compliance:

no

Type of assay:

in vitro mammalian chromosome aberration test

Test material

Test material information

Constituent 1

Reference substance name:

64741-52-2

Cas Number:

64741-52-2

IUPAC Name:

64741-52-2

Constituent 2

Reference substance name:

light hydrotreated feedstock, insufficiently refined, IP 346 ≥ 3%

IUPAC Name:

light hydrotreated feedstock, insufficiently refined, IP 346 ≥ 3%

Test material form:

other: oily liquid

Details on test material:

Read across to unrefined and acid treated oils
- Name of test material (as cited in study report): L-06 Light Hydrotreated Feedstock
- Physical state: liquid
- Lot/batch No.: 96524
- Expiration date of the lot/batch: 09/19/90
- Stability under test conditions: not determined by Microbiological Associates, Inc.
- Storage condition of test material: room temperature

Method

Target gene:

ovary

Species / strain

Species / strain / cell type:

Chinese hamster Ovary (CHO)

Metabolic activation:

with and without

Metabolic activation system:

Aroclor 1254 rat liver

Test concentrations with justification for top dose:

Dose levels of 0.2, 0.1, 0.05 and 0.02 uL/mL without S-9 activation and 0.03, 0.15, 0.08 and 0.03 uL/mL with S-9 activation were used.

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO

Controls

Untreated negative controls:

yes

Remarks:

untreated cells

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

triethylenemelamine

Remarks:

Migrated to IUCLID6: Cyclophosphamide used for S-9 activated study

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)
DURATION
- Preincubation period: 16-24 hours
- Exposure duration: 10 non-activation, two hours for S-9 activated
- Expression time (cells in growth medium): 8 hours
- Fixation time (start of exposure up to fixation or harvest of cells): 10 hours

NUMBER OF CELLS EVALUATED: 100 metaphase cells were examined for each dose level.


DETERMINATION OF CYTOTOXICITY
- Method: relative total growth

Evaluation criteria:

The number of types of aberrations found was presented for each treatment group. The percentage of damaged cells in the total population of cells examined was calculated for each group. Frequency of structural aberrations per cell was calculated for each group.

Statistics:

Student's t test was used to analyze the frequency of structural aberrations per cell. Chi-square analysis using a 2x2 table was used to ascertain differences between the percentage of cells with numerical aberrations and each treatment group relative to the vehicle control.

Results and discussion

Test results

Species / strain:

Chinese hamster Ovary (CHO)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

RANGE-FINDING/SCREENING STUDIES: Dose levels for chromosome aberration assay were selected based on preliminary toxicity tests based on cell survival after treatment relative to the solvent control. CHO Cells were exposed to nine concentrations of test article ranging from 1.0 uL/mL to 0.0001 uL/mL in the presence and absence of an S-9 reaction mixture.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

The positive and negative controls fulfilled the requirements for a valid test. Under the conditions of the assay, L-06 did not induce a statistically significant increase in the frequency of structural or numerical aberrations in the CHO cells, in the absence or presence of metabolic activation system.

Executive summary:

Read across justification

No in vitro chromosome aberration tests have been reported for slack waxes (carcinogenic or unknown feed-stock), but such studies have been reported for unrefined / acid treated lubricant base oils, materials similar to the oil entrained in slack waxes (carcinogenic or unknown feed-stock).

In a mammalian cell chromosome aberration study, CHO cell cultures were exposed to L-06 in DMSO at concentrations of 0.2, 0.1, 0.05 and 0.02 µL/mL without S-9 activation and 0.03, 0.15, 0.08 and 0.03 µL/mL with S-9 activation for 10 hours for non-activation and two hours for activation. L-06 was tested up to precipitating concentrations. Positive controls induced the appropriate response. The test material did not demonstrate mutagenciity in the chromosomal aberration assay using Chinese hamster ovary cells.

This study received a Klimisch score of 1 and is classified as reliable without restriction because it was conducted according to or similar to guideline study OECD TG 473.