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Long-term toxicity to fish

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Fatty acids, C18-unsaturated, dimers (CAS No. 61788-89-4) is expected to show no chronic effects up to the limit of the water solubility (<0.12 mg/L). The NOEC (28 d) was determined to be > 0.850 mg/L.

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Additional information

As no long-term toxicity tests to fish are available for Fatty acids, C18-unsaturated, dimers (CAS No. 61788-89-4), in accordance to Regulation (EC) No. 1907/2006, Annex XI, 1.5, a read-across to another structurally related category member, i.e. Fatty acids, C18-unsaturated, dimers, hydrogenated (CAS No. 68783-41-5) was conducted. Both substances are derived from Fatty acids, C16-18 and C18-unsaturated, dimerised (CAS No 71808-39-4), the crude dimer. The only difference between the two “dimer acids” is the degree of saturation or hydrogenation. Data from the MITI-database (MOE, 2003; MOE, 2008) indicate for C16/C18 fatty acids a slightly higher toxicity of unsaturated forms than the saturated forms, however this MITI data also shows that the length of the chain is correlated to the level of toxicity. For dimerised C18 chains resulting in 36 carbon molecules, i.e. a duplication of C atoms, this is directly reflected by the very low water solubilities (both < 0.52 mg/L). As the C16-and C18 fatty acids are in general more water soluble than dimerised fatty acids it is not expected that effects will occur up to the limit of water solubility regardless of the level of saturation and thus read across for to the C36 saturated form to the unsaturated form is fully valid.

 

This long-term toxicity test conducted in accordance with GLP and to ISO/DIS 10229-1 with the fresh water fish Danio rerio reports a NOEC (28 d) of ≥ 0.850 mg/L, and concludes that no effects occur up to the limit of the water solubility for Fatty acids, C18-unsaturated, dimers, hydrogenated, CAS No. 68783 -41 -5). Due to the low water solubility of the test substance a vehicle (DMSO) was used. Continuously flowing test solutions were generated from a constant-head tank containing dilution water and from a series of stocks which were dosed into the test vessels via a peristaltic pump.

 

Therefore, due to structural similarities with the tested category member this result also applies to Fatty acids, C18-unsaturated, dimers (CAS No. 61788-89-4) and no chronic effects to fish are expected to ocurr up to the water solubility limit (< 0.12 mg/L, detection limit).

 

References:

Ministry of the Environment, Government of Japan (2003).Daphnia magna, reproduction test by oleic acid. Food Research Laboratories. Report No. 14053. 2003-03-31.

Ministry of the Environment, Government of Japan (2008).Daphnia, reproduction toxicity test for palmitic acid. Mitsubishi Chemical Safety Institute Ltd.,Laboratory. Report No. A050381. 2008-02-14.