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The aquatic hazard assessment of Reaction mass of sodium hydrogen N-(1-oxooctadecyl)-L-glutamate and stearic acid was performed using test results with the substance itself and available data for the source substances l-Glutamic acid, N-coco acyl derivs., monosodium salts (CAS No. 68187-32-6) and stearic acid (CAS No. 57-11-4), which were used in a read across approach in accordance with Regulation (EC) No 1907/2006, Annex XI, 1.5.

The read across approach is considered valid since l-Glutamic acid, N-coco acyl derivs., monosodium salts is structurally very similar to the main component and stearic acid is identical to the second, quantitatively relevant, component of the multiconstituent substance. l-Glutamic acid, N-coco acyl derivs., monosodium salts is structurally identical to the main component L-Glutamic acid, N-(1-oxooctadecyl)-, monosodium salt only differing in the length of the carbon side chain. Whereas the length of the carbon side chain of l-Glutamic acid, N-coco acyl derivs., monosodium salts may vary between C6 to 18, the carbon side chain of L-Glutamic acid, N-(1-oxooctadecyl)-, monosodium salt is C18 only. As the relevant physico-chemical properties (log Kow < 1, water solubility = high) are similar which assumes identical environmental behavior and as molecules with shorter carbon side chains are expected to be up taken more easily into organisms, the source substance can be considered as worst case scenario for assessing the ecotoxicity of the main component of Reaction mass of sodium hydrogen N-(1-oxooctadecyl)-L-glutamate and stearic acid.

 

Since no studies investigating the short-term toxicity of Reaction mass of sodium hydrogen N-(1-oxooctadecyl)-L-glutamate and stearic acid to freshwater fish and aquatic invertebrates are available, available data for the source substances l-Glutamic acid, N-coco acyl derivs., monosodium salts (CAS No. 68187-32-6) and stearic acid (CAS No. 57-11-4) were used. The key studies showed a 96h-LC50 of 62.4 mg/L for fish and a 48h-EC50 of 49 mg/L for aquatic invertebrates. Supporting studies showed no toxicity of stearic acid to fish.

 

Studies investigating the toxicity of Reaction mass of sodium hydrogen N-(1-oxooctadecyl)-L-glutamate and stearic acid to algae and aquatic microorganisms are available. A 72h-EC50 of 200 mg/L is determined for algae and a 3h-EC10 of > 1000 mg/L is determined for aquatic microorganisms. As the substance is readily biodegradable no toxicity was expected for microorganisms. The test result confirmed this assumption. Thus, the inhibition of the biodegradation activity of activated sludge in STPs is not anticipated.

Giving these results Reaction mass of sodium hydrogen N-(1-oxooctadecyl)-L-glutamate and stearic acid is considered to be harmful to aquatic organisms. Aquatic invertebrates are indicated as most sensitive organism.

Regarding chronic data, one long-term toxicity test effect value for freshwater algae and one for aquatic invertebrates is available. The algal test determined a 72h-EC10 of 73 mg/L. The long-term toxicity test with Daphnia magna determined a 21d-NOEC value of 0.218 mg/L based on recalculated measured concentrations using the TWA method. Results of long-term toxicity tests with fish are not available and not considered to be necessary since valid chronic data for the most sensitive organisms (here aquatic invertebrates) are available.