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

Long-term toxicity to fish

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 fish 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. Four reliable read-across studies are available for aluminium sulfate and aluminium chloride. The substance fatty acids, C16-18 (even numbered), aluminum salts, is produced from natural fatty 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% of 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 the poor water solubility, the amount of dissolved aluminum is very low (max. 5 µg Al/L). The fatty acid component is readily biodegradable and therefore it will undergo rapid and ultimate degradation in most environments. Fatty acids are natural constituents of the 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 the environment is expected for the C16-18 fatty acid component. Therefore, read-across from two well soluble aluminium compounds: aluminium sulfate (CAS 10043-01-3) and aluminium chloride (CAS 7446-70-0) represent the worst case scenario for low soluble fatty acid, C16-18 (even numbered), aluminum salts, in aquatic ecosystems.

Cleveland et al. (1989) exposed Salvelinus fontinalis to aluminium sulfate for 60 days in a non-GLP study. No special guideline was followed. The hardness was reported as 246 µeq/L and pH was 6.5. The NOEC values were determined for mortality, length, weight, number hatched and swimming behavior, and ranged between 57 to >350 µg/L of total Al.

In a 28 day non-GLP study with Pimephales promelas Kimball (1978) exposed fish to aluminium sulfate at a pH of around 7.3 and under hard water conditions. The NOEC values were determined for mortalities of the fry, weight, length, and number hatched. Based on total Al the NOECs were in the range of 4.7 to 23.1 mg/L.

Freeman and Everhart (1971) conducted a 42-day test with rainbow trout under flow-through conditions. Juvenile fish were exposed to aluminium chloride in concentrations 0, 0.052 ppm, 0.52 ppm, 5.2 ppm as total Al at pH 7.0, 8.0, 8.5, 9.0. Concentrations of 5.2 ppm Al from all tested pH values exhibited toxic effects. It was concluded that if aluminium is present only in anionic and neutral or near neutral precipitated form, the tolerable concentrations should not exceed 0.05 mg Al/L (NOEC value).

Finally, Gundersen et al. (1994) exposed rainbow trout in a non-guideline study for 16 days to AlCl3 at a water hardness of 10 and 100 mg/L as CaCO3 and at pH 7.3 and 8.3. NOECs reported for pH 8 were around 1.5 mg/L (total Al) and 0.15 mg/L (dissolved Al). There was no significant difference between effect values at different water hardness.

It is important to stress that both read-across substances - aluminium chloride and aluminium sulfate are not classified as hazardous for the aquatic environment according to Regulation 1272/2008.

The effects observed in the long-term fish testing with these two 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).