Paraffin waxes (Fischer-Tropsch), isomerization

Endpoint summary

Description of key information

- low toxicity to terrestrial dwelling organisms, based on toxicity studies for GTL base oil [C18-C50, branched, cyclic and linear, CAS 848301-69-9] - covering the low molecular weight fraction of the registration substance up to C50 - that are available with soil macroorganisms (Eiseinia foetida), terrestrial plants (Glycine max, Lycopersicon esulentum, Sinapis alba, Avena sativa, Lolium perenne) and soil microorganisms and birds;

- it is concluded that the results of GTL base oil are also applicable for the registration substance 'Paraffin waxes (Fischer-Tropsch), isomerization' containing higher molecular weight constituents (C25-150, about 30-55 % >C50) since hydrocarbons >C50 are expected to be less bioavailable.

Additional information

No terrestrial toxicity data are available for the regsitration substance 'Paraffin waxes (Fischer-Tropsch), isomerization'.

However, toxicity studies for related GTL-derived substances - covering the carbon range, C18 to C50, of the registration substance - are available with soil macroorganisms (Eiseinia foetida), terrestrial plants (Glycine max, Lycopersicon esulentum, Sinapis alba, Avena sativa, Lolium perenne) and soil microorganisms.

 

Several studies with terrestrial organisms are available for the closley related substance GTL base oil (CAS 848301-69-9, EC 482-220-0) consisting of linear and branched alkanes (paraffins) with a small amount of cycloalkanes in the carbon range from C18 to C50:

A short-term and a long-term toxicity study are available with the earthworm Eisenia foetida. The studies reported respectively a 14-day LC50 value of >1000 mg/kg dw and a 4 week NOEC value of ≥1000 mg/kg dw. A nitrogen transformation test resulted in an EC50 (28-d) value of >1000 mg/kg based on nitrate formation rate.

Additionally, in a plant seedling emergence and growth test five plant species, three dicotyledonous species, soybean (Glyicine max), tomato (Lycopersicon esulentum) and mustard (Sinapis alba) and two monocotyledonous species, oat (Avena sativa) and perennial ryegrass (Lolium perenne) no effects were recorded after 21 or 22 days exposure up to a concentration of 1000 mg/kg dw.

 

Supporting studies for toxicity to honeybees (OECD 213 and 214) and terrestrial plants (OECD 208) are also available for the substance GTL Solvent GS 310 (C18-C24), which add further evidence for the lack of toxicity of hydrocarbons in the relevant carbon range to terrestrial organisms.

 

The available data on GTL base oil and GTL Solvent GS 310 likely mimic a worst-case scenario for terrestrial toxicity of the target substance, because their results are based on smaller hydrocarbons constituents. GTL Base Oil typically contains hydrocarbons in the range of C18 to C50 and GTL Solvent GS 310 ranges form C18 to C24, thus covering the low molecular weight fraction of the registration substance (C25-C150, about 30-55% >C50).

Overall, the studies indicate that the closely related substance GTL Base oil exhibit low toxicity to terrestrial dwelling organisms; it is concluded that the results are also applicable for the registration substance containing higher molecular weight constituents (C25-C150, about 30-55 % >C50) since hydrocarbons >C50 are expected to be less bioavailable (due to the low water solubility and enhanced size).