Oleic acid, copper salt

Toxicity to aquatic algae and cyanobacteria

Description of key information

Aquatic toxicity data of oleic acid, copper salt are not available. Thus, read-across to the assessment entities soluble copper substances and oleic acid is applied since the ions of oleic acid, copper salt determine its fate and toxicity in the environment.Reliable studies indicate that the moiety of ecotoxicological concern are copper cations. Based on copper toxicity to freshwater algae, species mean NOEC values of 43 µg/L Cu for Pseudokirchernella subcapitata and 138 µg/L Cu for Chlorella vulgaris were reported. In addition, with copper being an essential element to algae and cyanobacteria, a concentration of 1-35 µg/L Cu was determined as optimal concentration range for algal growth. Individual NOECs available for marine diatom species Phaeodactylum tricornutum and macroalgae Macrocystis pyrifera range from 2.9 µg Cu/L to 50 µg Cu/L, respectively with species-mean NOEC values ranging from 2.9 µg/L Cu (Phaeodactylum tricornutum) to 11 µg/L Cu (Fucus vesiculosis). Data for oleic acid (i.e. C18- fatty acids) point to a low (if any) toxic potential to aquatic algae. Thus, oleic acid, copper salt appears to have potential for toxicity to aquatic algae and cyanobacteria based on the toxicity of its dissociation products.