Oil shale, thermal processing waste

Endpoint summary

Additional information

Testing Burnt Oil shale (BOS)-P.1082 for genotoxic potential with Ames test according to OECD guideline 471 was performed with the Salmonella typhimurium strains TA98, TA 100, TA 102, TA 1535 and TA1537 (Holcim, 2010a). Test concentrations of 0 (solvent control), 31.6, 100, 316, 1000, 2500 and 5000 µg/plate with and without metabolic activation by S9 mix revealed negative results. During the mutagenicity test and under the experimental conditions reported, the test article did not induce point mutations by base-pair changes or frameshifts in the genome of the strains used. Therefore, the test substance is not considered to be mutagenic in this Salmonella typhimurium strains.

Mutagenicity of the test substance Burnt oil Shale(BOS)-P.1082 in mammalian cells in vitro was determined in the L5178Y mouse lymphoma cell line according to OECD guideline 476 (Holcim, 2010b). The number of mutants derived from 5 exposure plates

was determined in 2 independent exeriments. In the first experiment the mouse lymphoma cells were exposed for 4 hours to test substance concentrations ranging from 0 to 5000 µg/mL in the absence and presence of the metabolic activation system rat liver S9-mix. In the second experiment the mouse lymphoma cells were exposed for 4 hours in presence and 24 hours in absence of the metabolic activation system rat liver S9-mix to test substance concentrations ranging from 0 to 5000 µg/mL.

Due to the nature of the test item it was not possible to prepare a solution of the test item with an appropriate solvent. Therefore the test item was suspended in RPMl + 3% horse serum for short-term exposure or RPMl + 7.5% horse serum for long-term exposure and diluted prior to treatment. Precipitation of the test item was noted in experiment 1 and experiment 2 at all concentrations tested. There was no significant increase of mutant frequencies at the TK locus compared to the control groups at short term treatment groups. Only for long term exposure at precipitating concentrations the test item was considered to be mutagenic. Because this is only observed in this in vitro experiment and not in the Ames test or MN it is concluded that these effects were from side effects dependent on the low solubility of the test substance.

 

An in vitro mammalian micronucleus test with Burnt Oil shale (BOS) in human lung epithelial A549 cells according to OECD guideline 487 was performed (Holcim, 2010c). The cells were treated with BOS-P.1034 1.Schicht (62.5 and 31.3 µg/cm²) and -P.1034 2.Schicht (125 and 62.5 µg/cm²) for 24 hours. Concentrations were selected based on cytotoxicity data obtained with LDH assay conducted with same test substances and the same cell lines. Treatment with the test substances resulted in hardly any cytotoxicity. The frequencies of micronuclei were compared with those of concurrent negative controls (untreated cells). Under the experimental conditions, none of the test substances did induce a clastogenic response in A549 cells, under the conditions used in this study.

Short description of key information:
In vitro: Gene mutation bacteria (Ames OECD 471): negative;
In vitro: Gene mutation in mammalian cells (Mouse lymphoma, OECD 476): negative
In vitro: Mammalian Erythrocyte Micronucleus Test (OECD 487): negative

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

According to DSD and CLP Burnt Oil Shale has not to be classified for its genotoxic potential.