Hydrocarbons, C16-C22, n-alkanes, isoalkanes, <2% aromatics

Short-term toxicity to fish

Description of key information

(96-h) LL50 >1000 mg/l P. Promelas and B. rerio (read-across, reliability 2).

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

1 000 mg/L

Additional information

Measured acute (short-term) toxicity data are available for Hydrocarbons, C18-C24, isoalkanes, <2% aromatics to the freshwater fish Cyprinus carpio (carp) (Tobor-Kaplon, 2014). The test was conducted under semi-static conditions (daily renewal of the test media) in accordance with OECD Test Guideline 203. Appropriate modifications to the test and media preparation procedures were made to take account of the test substance containing multiple constituents, having low solubility in water and being potentially volatile in accordance with OECD guidance on aquatic toxicity testing of difficult substances and mixtures (OECD, 2000). No mortality or clinical effects inC. carpiowere observed after 96 hours exposure to the test medium prepared as a water-accommodated fraction (WAF) at loading rates of up to 100 mg/l; 96-hour LL50 >100 mg/l, NOELR ≥100 mg/l. TOC concentrations were analysed in samples taken from the control and WAF prepared at 100 mg/l. In all cases the concentrations were below the limit of detection of the method (1.0 mg/l). The results of the test are considered to be reliable.

The acute toxicity of a sample of GTL Gasoil (Shell SMDS-2) was determined by Palmer (2002) in a test with the fishPimephales promelas(Fathead minnow). The test was conducted in accordance with OECD Test Guideline 203.

Water-accommodated fractions (WAFs) of the sample were prepared in sealed vessels with minimum headspace, by stirring for approximately 72 hours. The contents of the vessels were left to stand for 1-2 hours before drawing off the aqueous phase – the WAF – for testing. Semi-static exposures were then carried out in completely full, sealed vessels. The tests were not subject to GLP and the test media were not analysed for stability or for exposure concentration of the test substance. However in other respects they were considered to fulfil the requirements of current best practice.

The test results, expressed as the LL₅₀value, showed that the sample was not acutely toxic to fish at a loading rate of 1000 mg/l.

Albertus and Phillips (2005) have reported results for anacute toxicity test carried out on a second sample of the substance (SASOL SPD™ Diesel)with the fishBrachydanio rerio(Zebrafish).The test was conducted in accordance with OECD Test Guideline 201. The test media were WAFs of the test sample that were prepared in sealed vessels with a small headspace according to the CONCAWE methodology for the ecotoxicological testing of petroleum products (CONCAWE report, 1993).

The test results, expressed as the LL₅₀value, showed that the sample was not acutely toxic to fish at a loading rate of 1000 mg/l.

The short-term toxicity of GTL Base Oil Distillates to freshwater fishBrachydanio rerio(zebra fish) has been determined by Han (2008). The test was conducted in accordance with OECD Test Guideline 203.

Water-accommodated fractions (WAFs) of the sample were prepared in jars, by stirring for approximately 24 hours. The contents of the vessels were left to stand for 2 hours before drawing off the aqueous phase – the WAF – for testing. Semi-static exposures were then carried out.

The test was conducted in accordance with GLP and the TOC of test media were analysed for stability and exposure concentration. Total Organic Carbon (TOC) analysis of the freshly prepared test preparations showed amount of carbon present within the 1000 mg/l loading rate WAF test vessels to range from 1.71 mg C/l to 1.79 mg C/l. TOC analysis of the old test media showed amount of carbon present to range from 1.56 mg C/l to 1.64 mg C/l. There was no significant difference in TOC content between control and exposure vessels. This was expected by the authors due to the low water solubility of the test substance. 

The test results, expressed as the LL₅₀value, showed that GTL Base Oil Distillates was not hazardous to fish at a loading rate of 1000 mg/l WAFs.

Conclusion

Short-term fish toxicity tests are available for several substances in the relevant carbon number range for the registration substance. In the absence of adverse effects in these studies it can be concluded that, based on weight of evidence, the LLR₅₀ (freshwater fish) for Hydrocarbons, C16-C22, n-alkanes, isoalkanes, <2% aromatics is >1000 mg/l.