Fatty acids, C16-18 (even numbered), aluminum salts

Long-term toxicity to aquatic invertebrates

Description of key information

No effect are to be expected up to the limit of water solubility. 

Additional information

Since no long-term toxicity data with aquatic invertebrates are available for fatty acids, C16-18 (even numbered), aluminum salts, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5, read-across data from other structurally related substances are provided. Three reliable read-across studies are available for aluminium chloride (CAS 7446-70-0), aluminium sulfate (CAS 10043-01-3) and palmitic acid (CAS 57-10-3). The substance fatty acids, C16-18 (even numbered), aluminum salts, is produced from natural fatty acid materials which is a mixture of stearic (C18) and palmitic (C16) acid. The substance consists of up to 90% natural fatty acid and up to 10% aluminum. Fatty acids, C16-18 (even numbered), aluminum salts, are present in water in dissociated form as different Al species and ionic fatty acid component. Due to poor water solubility, the amount of dissolved aluminium will be very low (max. 5 µg/L). The fatty acid component is readily biodegradable and therefore it undergoes rapid and ultimate degradation in most environments. Fatty acids are natural constituents of environment and are essential for a balanced nutrition of animals. Due to this fact and also due to their low water solubility no hazard to environment is expected for the C16-18 fatty acid moiety; nevertheless the available data with palmitic acid (C16) are presented. Read-across from well soluble aluminium compounds like aluminium chloride and aluminium sulfate represent the worst case scenario of aquatic toxicity of low soluble fatty acid, C16-18 (even numbered), aluminum salts.

Biesinger and Christensen (1972) conducted a non-GLP Daphnia magna reproduction test with aluminium chloride. No special guideline was followed. The experiment was performed under semi-static conditions. The 21-day EC50 value determined for the reproduction of daphnids was 0.68 mg total Al/L. The NOEC value for the reproduction was 0.16 mg total Al/L.

A non-GLP Daphnia magna reproduction study by Kimball (1978) was conducted with aluminium sulfate. The test was performed for 28 days under semi-static conditions. The 28-day EC50 value for mortality was 1.61 mg total Al/L and the NOEC value for reproduction was 1.89 mg total Al/L.

The study with palmitic acid (Ministry of the Environment, Government of Japan, 2008) was conducted according to OECD 211 and is GLP compliant. The limit test with 98.7% pure palmitic acid with Daphnia magna lasted 21 days and the long-term effects on the adult daphnids led to an LC50 (21d) of > 0.22 mg/L and a NOEC (21d) of > 0.22 mg/L for reproduction. Thus, no long-term toxic effects on invertebrates were observed up to the limit of water solubility.

It is important to stress that the read-across substances - aluminium chloride, aluminium sulfate and palmitic acid are not classified as hazardous for the aquatic environment according to Regulation 1272/2008. The effects observed in the long-term invertebrate testing with these three read-across substances occur above the water solubility limit of fatty acids, C16-18 (even numbered), aluminum salts. Therefore, no toxic effects of this substance are expected below its water solubility level which is < 0.15 mg substance/L or < 5 µg Al/L. Moreover no toxic effects were observed in the short-term testing with fatty acids, C16-18 (even numbered), aluminum salts up to the limit concentration of 100 mg/L (WAF).