Zirconium, acetate lactate oxo ammonium complexes

Toxicity to aquatic algae and cyanobacteria

Description of key information

Aquatic toxicity data of zirconium, acetate lactate oxo ammonium complexes are not available. Zirconium, acetate lactate oxo ammonium complexes consists of ammonium [NH4]+ and zirconium [Zr]4+ cations and acetate [CH3COO]2- and lactate [CH3CH(OH)COO]2- anions. A complete dissociation of zirconium, acetate lactate oxo ammonium complexes resulting in ammonium, zirconium, acetate and lactate ions may be assumed under environmental conditions. Since acetate, ammonium, lactate and zirconium ions upon release behave differently in the environment, the fate and toxicity of acetate, ammonium, lactate and zirconium ions in the environment is most accurately assessed separately.

An 8-d LOEC of 90 mg/L obtained in a test with acetic acid and cyanobacteria M. aeruginosa is slightly below the OECD test limit of 100 mg/L. However, the test was conducted without pH adaption and thus, a pH-driven effect is very likely.

Lactate is non-toxic to green algae P. subcapitata with a 70h-EC50 of 3500 (growth) and > 2800 (biomass) mg/L, respectively. QSAR based 96-h EC50 values for acetate and lactate are well above the OECD test limit of 100 mg/L as well.

Ammonium chloride is non-toxic to freshwater algae C. vulgaris with a 5d-EC50 of 1300 mg/L.

Zirconium is poorly soluble and precipitates under most environmental conditionswhereas neodecanoate is rather mobile.Although, in a 72-h test according to OECD 201 (2006) with zirconium dioxide a 72 -h NOErL (growth rate) of 32 mg/L was determined for D. subspicatus, the inhibitory effect on the growth of algae may be explained (at least in part) with the measured simultaneously occuring phosphate depletion in the grwoth medium. Further, the derived EL50 was above the respective OECD test limit.

In sum, a hazard was not identified for any of the dissociation products of zirconium, acetate lactate oxo ammonium complexes and thus a low potential for toxicity to algae and cyanobacteria is assumed for zirconium, acetate lactate oxo ammonium complexes.