Copper(2+) neodecanoate

Toxicity to aquatic algae and cyanobacteria

Description of key information

Aquatic toxicity studies of copper (2+) neodecanoate are not available. Thus, read-across to the assessment entities soluble copper substances and neodecanoic acids is applied since the ions of copper (2+) neodecanoate 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 Pseudokirchneriella 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 neodecanoic acid point to a low toxic potential to freshwater algae with a 72-h EL50 of >100 mg/L based on inhibition of growth of R. subcapitata.

Following its dissolution in aqueous media, the toxicity of Copper (2+) neodecanoate to aquatic algae and cyanobacteria is determined by copper cations and neodecanoate anions. Data is available for toxicity of copper ions to aquatic algae and cyanobacteria, including freshwater as well as marine algae. Regarding 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. Marine algae NOECs available for diatom species Phaeodactylum tricornutum and macroalgae Macrocystis pyrifera revealed individual NOECs ranging from 2.9 µg Cu/L to 50 µg Cu/L, respectively with additional high quality marine algae species mean NOEC values ranging from 2.9 µg/L Cu (Phaeodactylum tricornutum) to 11 µg/L Cu (Fucus vesiculosis). Regarding the neodecanoate anion, acute toxicity data on neodecanoic acid (versatic 10) was evaluated for freshwater algae R. subcapitata yielding an 72-h LL50 of > 100mg/L. Thus, Copper (2+) neodecanoate appears to have potential for toxicity to aquatic algae and cyanobacteria based on the toxicity of its dissociation products.