Peracetic acid

Toxicity to aquatic algae and cyanobacteria

Description of key information

EC50 (72 h): 0.16 mg/L (EPA OPP 123-3; Pseudokirchneriella subcapitata)
NOEC (72 h): 0.061 mg/L (EPA OPP 123-3; Pseudokirchneriella subcapitata)

Key value for chemical safety assessment

EC50 for freshwater algae:

0.16 mg/L

EC10 or NOEC for freshwater algae:

0.061 mg/L

Additional information

The toxicity of equilibrium peracetic acid (5.2%) to the freshwater green alga (Pseudokirchneriella subcapitata, formerly known as Selenastrum capricornutum) was determined at nominal concentrations of 0, 0.065, 0.13, 0.25, 0.50 and 1.0 mg/L in accordance with EPA OPP 123-3 (Hicks et al., 1996). The concentrations of peracetic acid were measured indirectly by converting the hydrogen peroxide concentrations to peracetic acid equivalent concentrations. At the end of the test, the measured concentrations were lower than the detection limit except for concentrations of 0.50 and 1.0 mg peracetic acid/L where the remaining measured H2O2 concentrations were 84% and 110% of the nominal values, respectively. The disappearance of the test substance in the lower concentrations was attributed by the study author to degradation. However, the fact that the test substance could be verified in the two highest nominal concentrations where the algal density was more or less zero is indicative for adsorption of peracetic acid on the algae rather than degradation. Based on the cell count at the end of the test, a concentration of 0.061 mg/L was considered to be a NOEC after 72 hours and the EC50 value was estimated to be 0.16 mg/L.

 

Two other studies with Pseudokirchneriella subcapitata (Petit-Poulsen et al., 1997; Hanstveit and Schoonmade, 1999) and one study with Desmodesmus subspicatus (reported as Scenedesmus subspicatus) (L'Haridon, 2003) are supportive of the above values, although thy show lower toxicity as the determined NOEC 50 are in the range of 0.084 < 1 mg/L.