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

Long-term toxicity to aquatic invertebrates

Description of key information

(21-d) NOELR ≥100 mg/l D. magna (read-across, reliability 2).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

A Daphnia reproduction study has been conducted with GTL Gasoil using the freshwater species Daphnia magna (Goodband, 2011). The test was conducted in accordance with OECD 211 and was compliant with GLP.

Daphnia magna were exposed to water accommodated fractions (WAFs) of the test material over a range of nominal loading rates of 10, 32 and 100 mg/l for a period of 21 days under semi-static test conditions. The test was conducted using completely full test vessels which were covered to minimise any potential for volatile losses of the test substance.

The 21-d EL₅₀(immobilisation) value, based on nominal loading rates, for the parental Daphia generation (P₁) was between 32-100 mg/l loading rate WAF.

The 21-d EL₅₀(reproduction) value, based on nominal loading rates was between 32-100 mg/l loading rate WAF.

The lowest Observed Effect Loading Rate (LOELR) was considered to be 100 mg/l on the basis that at this loading rate, although no significant differences (P³0.05) were observed between the control and the 100 mg/l loading rate WAF test group in terms of numbers of live young produced per adult by Day 21, significant mortalities (immobilisation) were observed in the parental generation (P₁).

The No Observed Effect Loading Rate (NOELR) was considered to be 32 mg/l on the basis that at this loading rate there were no significant mortalities (immobilisation) observed in the parental generation (P₁) and that there were no significant differences (P³0.05) between the control and the 32 mg/l loading rate WAF test group in terms of numbers of live young produced per adult by Day 21.

Total Organic Carbon (TOC) analysis of the freshly prepared test preparations showed amount of carbon present within the 10, 32 and 100 mg/l loading rate WAF test vessels to range from less than the limit of quantitation (LOQ) for the method (1.0 mg carbon C/l) to 8.91 mg C/l. TOC analysis of the old test media showed amount of carbon present to range from less than the LOQ to 1.84 mg C/l.

An invertebrate reproduction study has been conducted with GTL Base Oil Distillates using the freshwater species Daphnia magna (Goodband, 2010). The test was conducted in accordance with OECD 211 and was compliant with GLP.

Daphnia magna were exposed to water accommodated fractions (WAFs) of the test material over a range of nominal loading rates of 10, 32 and 100 mg/l for a period of 21 days under semi-static test conditions. The WAFs were prepared by stirring for 23 hour and then leaving to stand for 1 hour.

The Lowest Observed Effect Loading Rate was considered to be greater than 100 mg/l on the basis that at this loading rate, no significant differences (P³0.05) were observed between the control and the 100 mg/l WAF loading rate in terms of numbers of live young produced per adult by Day 21.

The No Observed Effect Loading Rate (NOELR) was considered to be 100 mg/l on the basis that at this loading rate there were no significant mortalities (immobilisation) observed in the parental generation (P₁) and that there were no significant differences (P³0.05) between the control and the 100 mg/l loading rate WAF test group in terms of numbers of live young produced per adult by Day 21.

Total Organic Carbon (TOC) analysis of the freshly prepared test preparations showed amount of carbon present within the 10, 32 and 100 mg/l loading rate WAF test vessels to range from less than the limit of quantitation (LOQ) for the method (1.0 mg C/l) to 1.60 mg C/l. TOC analysis of the old test media showed amount of carbon present to range from less than the LOQ to 1.20 mg C/l. 

Conclusion

Long-term invertebrate toxicity tests are available for two GTL-derived substances in the relevant carbon number range for the registration substance. In the test with GTL Base Oil Distillates (C18 -C50) there were no adverse effects at the highest loading rate (100 mg/l). In the test with GTL Gasoil (C8 -C26) the NOELR was determined to be between 32 and 100 mg/l based on mortality in the parental generation at the highest rate. However, it is considered likely that the effects observed are attributable to the lower carbon number constituents of the GTL Gasoil. This is supported by measured data on constituents reported by CONCAWE in which long-term effects on Daphnia were observed with a C12 constituent, but no effects up to the limit of solubility were observed with constituents ≥C13 (see Section 7.7 of the Chemical Safety Report attached in Section 13). Based on weight of evidence it can therefore be concluded that for Hydrocarbons, C16-C22, n-alkanes, isoalkanes, <2% aromatics, the long-term NOELR for freshwater invertebrates is ≥100 mg/l.