Fatty acids, rape-oil, mixed esters with 1,4:3,6-dianhydro-d-glucitol, sorbitan and sorbitol

Long-term toxicity to aquatic invertebrates

Description of key information

No effects up to the limit of water solubility (OECD 211).

Additional information

Since no studies investigating the long-term toxicity of Fatty acids, rape-oil, mixed esters with 1,4:3,6-dianhydro-d-glucitol, sorbitan and sorbitol (CAS 93334-10-2) to aquatic invertebrates are available, in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5 a read across to the structurally related analogue substances sorbitane stearate (CAS 1338-41-6) and Sorbitan, (Z)-9-octadecenoate (2:3) (CAS 8007-43-0) was conducted.
This read-across is justified as all substances share a comparable structure. Based on the specification the target substance Fatty acids, rape-oil, mixed esters with 1,4:3,6-dianhydro-d-glucitol, sorbitan and sorbitol is characterized by the alcohol components sorbitol, sorbitan and 1,4:3,6-dianhydro-d-glucitol esterified as mono (mainly), -di- or tri-ester with mainly fatty acids of C18 and C18 unsaturated. The source substance sorbitan stearate (CAS 1338-41-6) is characterized as a mono-, di- and tri-ester of sorbitan with C16-C18 fatty acids. Sorbitan, (Z)-9-octadecenoate (2:3) (CAS 8007-43-0) is an ester (mono, di and tri) of sorbitan, sorbitol and 1,4:3,6-dianhydro-d-glucitol with C18 unsaturated fatty acid. Further justification is given within the endpoint summary 6.1 and within the analogue justification in section 13.

The first key study conducted with the source substance Sorbitan stearate (CAS 1338-41-6) was performed according to OECD guideline 211 and GLP (Ministry of the Environment, Government of Japan, 2006). The test organism Daphnia magna was exposed to the test substance in a semi-static system for 21 days, at nominal concentrations of 5, 16, 50, 160 and 500 mg/L. The test concentrations 5 and 16 mg/L were prepared using tetrahydrofuran as pre-solvent. Before the test, the solvent was removed and the solution was filtered. The higher concentrations were prepared without solvent as water accommodated fractions (WAF). Since a solvent was used, the lower concentrations are not actual loading rates and these test concentrations cannot be evaluated as WAF. No inhibition of reproduction was observed during the test, in fact, the number of juveniles produced at 5 and 16 mg/L was higher than in the control. At the three higher concentrations, 100% mortality of the parental daphnia occurred, and reproduction could not be evaluated. The reported measured values for the three highest concentrations (4.65, 11.9, 17.1 mg/L) were significantly above the water solubility of the substance. Therefore, it can be assumed that undissolved test material was present and probably caused the mortality observed at the higher concentrations. Due to the methodological deficiencies in this test, the reported NOEC and LC50 need to be taken with caution. Nevertheless, at a nominal concentration of 16 mg/L the test solution was reported to be clear and colourless during the test period, and no adverse effects on mortality and reproduction occurred. The corresponding measured concentration 1.44 mg/L (nominal 16 mg/L) is clearly above the water solubility of sorbitan stearate (0.01 mg/L) and was probably only attained due to the use of solvent. Therefore, a NOELR (21 d) of ≥ 16 mg/L was derived and the higher test concentrations, where physical effects are likely to be responsible for the effects. Sorbitan stearate is thus not expected to have adverse effects on the reproduction of D. magna up to the limit of water solubility.

The second key study with the source substance Sorbitan, (Z)-9-octadecenoate (2:3) (CAS 8007-43-0) was performed according to OECD 211 and GLP (Parr, 2013). The test organism Daphnia magna was exposed to the test substance in a semi-static system for 21 days, at nominal loading rates of 10, 18, 32, 56 and 100 % v/v. Since no effects occurred, the loading rate 100 % v/v was determined to be used as NOELR. The corresponding time-weighted mean measured NOELR (21 d) ≥ 0.11 mg/L.

Based on the result from structurally related read-across substances (in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5) it can be concluded that Fatty acids, rape-oil, mixed esters with 1,4:3,6-dianhydro-d-glucitol, sorbitan and sorbitol will not exhibit long-term effects to aquatic invertebrates up to the limit of water solubility.