Fatty acids, lanolin, iso-Pr esters

Short-term toxicity to fish

Description of key information

No effects up to the limit of water solubility for Oncorhynchus mykiss (OECD 203)

Additional information

No studies on short-term fish toxicity are available for Fatty acids, lanolin, isopropyl esters (CAS 63393-93-1), which contains fatty acids from C10 to C29. Studies are available for isopropyl esters with C12, C14, C16 and C18 fatty acids (CAS Nos. 10233-13-3, 110-27-0, 142-91-6, 112-11-8), covering a large part of the constituents of Fatty acids, lanolin, isopropyl esters. Also for Fatty acids, C16-18 and C18 unsaturated, 2-ethylhexl esters (CAS No. 85049-37-9), the largest category member (C26, alcohol and fatty acid combined), a short-term fish study is available. All tested substances are practically insoluble in water, and toxic effects were observed in none of the studies. The metabolism of Fatty acids, lanolin, isopropyl esters is not assumed to significantly differ from the shorter fatty acid alcohol esters. All fatty acid alcohol esters are expected to be hydrolysed by lipases (Mattson and Volpenhein, 1972; and references therein). The resulting free fatty acids and alcohols are absorbed from the intestine into the blood stream. Fatty acids are either metabolised via the β-oxidation pathway in order to generate energy for the cell or reconstituted into glyceride esters and stored in the fat depots in the body. The reactions involved in the β-oxidation are slightly different for very long chain fatty acids (greater than C22). Whereas β-oxidation generally takes place in the mitochondria, very long chain fatty acids are oxidised in peroxisomes by slightly different enzymatic reactions (Reddy and Hashimoto, 2001; Singh et al., 1987; Le Borgne and Demarquoy, 2012; and references therein).It is known that fish peroxisomes have enzymatic systems similar to those reported in mammals (Rocha et al., 2003; and references therein). The final product of β-oxidation in mitochondria is acetyl-CoA, which directly enters the citric acids cycle (Berg, 2002). In peroxisomes, the reaction is incomplete giving rise to medium chain acyl-CoA, which are then taken in charge by the carnitine octanoyl transferase and converted into acyl-carnitine that can leave the peroxisome and, at least for some of them, may be fully oxidized in the mitochondria (Le Borgne and Demarquoy, 2012; and references therein). Consequently, despite the differences in fatty acid metabolism, Fatty acids, lanolin, isopropyl esters (CAS 63393-93-1), can be fully metabolised by aquatic organisms and is thus not expected to differ from the rest of the category in terms of toxicity to aquatic organisms. A read-across approach to other category members is therefore justified. Sincewater solubility is expected to be even lower, the tested substances represent a worst case compared to Fatty acids, lanolin, isopropyl esters. Since a conducting a fish test with Fatty acids, lanolin, isopropyl esters would most likely lead to ambiguous results, due to methodological difficulties caused by low water solubility, a read-across approach, using the available data, is considered the most reliable way to assess the short-term fish toxicity of the substance. This read across approach is in accordance with Regulation (EC) No 1907/2006, Annex XI, 1.5. Grouping of substance and read across approach. Further justification is given within the endpoint summary 6.1 and within the category justification in Section 13.

The key study with isopropyl laurate (CAS No. 10233-13-3) was performed according to OECD guideline 203, in a semi-static system, using Oncorhynchus mykiss as test organism (Jenkins, 1993). The fish were exposed to the nominal test concentrations of 62.5, 125, 250, 500 and 1000 mg/L. No mortality was observed within the 96-hour test period at any of the test concentration, and the LC50 was reported to be > 1000 mg/L.

The key study with isopropyl isostearate (CAS No. 68171-33-5) was performed as a limit test according to OECD guideline 203, in a static system, using Cyprinus carpio as test organism (Bogers, 1996). The fish were exposed to the nominal test concentration of 100 mg/L, prepared using the dispersant Tween-80. No mortalities were observed at any of the test concentrations, during the 96-hour test period, and the EC50 was reported to be > 100 mg/L.

The key study with Fatty acids, C16-18 and C18-unsaturated, 2-ethylhexyl esters (CAS No. 85049-37-2 was performed according to OECD Guideline 203 and GLP (Richterich, 2001). The test organism Brachydanio rerio was exposed to the test substance in a semi-static system for 96 hours, at nominal test concentrations of 1000, 3000 and 10,000 mg/L. No mortality occurred at any of the test concentrations, and an LC50 of > 10000 mg/L was reported.

Thus, based on theabove mentioned results, and due to the structural and profile similarities of the substances, as are explained within the overall endpoint summary 6.1 it can be concluded that no toxicological effects on fish are expected up tothe limit ofwater solubility for Fatty acids, lanolin, isopropyl esters (CAS 63393-93-1).