Dibo Liu

Comparison of the Toxicity of Wofasteril Peracetic Acid Formulations E400, E250, and Lspez to Daphnia magna, with Emphasis on the Effect of Hydrogen Peroxide

AbstractCommercial peracetic acid (PAA) formulations are acidic mixtures of PAA, hydrogen peroxide (H2O2), acetic acid, H2O, and stabilizers to maintain the equilibrium of the concentrations. Different PAA formulations show diverse PAA : H2O2 ratios, potentially leading to different toxicities at the same PAA concentration due to the different concentrations of H2O2 and stabilizers used. To confirm any potential differences in toxicity, we performed 24-h toxicity tests using Daphnia magna with three commercial PAA formulations (Wofasteril): E400, E250, and Lspez. The experiments were carried out in standard dilution water and with increased water hardness, salinity, or dissolved organic carbon to reflect various natural conditions. Results showed that the toxicity to Daphnia was greatest for Lspez, intermediate for E250, and lowest for E400. An E400 + H2O2 mixture, which possessed a composition theoretically identical to the E250 formulation, had toxic effects and 24-h LC50 values similar to those of E250...

Growth inhibition of Aeromonas salmonicida and Yersinia ruckeri by disinfectants containing peracetic acid

Peracetic acid (PAA) is a therapeutic agent used for disinfection in aquaculture, but it must be investigated thoroughly in order to mitigate diseases without harming the fish. Successful disinfectants (like PAA) should not leave dangerous residues in the environment in order to successfully contribute to sustainable aquaculture. The aim of our study was to compare the effectiveness of 6 commercial PAA products with different molecular PAA:H2O2 ratios to reduce bacterial growth of Aeromonas salmonicida and Yersinia ruckeri and to determine effective concentrations and exposure times. All products reduced colony-forming units (CFUs) of A. salmonicida and Y. ruckeri. Products with higher molecular PAA:H2O2 ratios inhibited growth better than products with lower molecular PAA:H2O2 ratios at the same PAA concentration; this indicates that H2O2 is not the driving force in the reduction of A. salmonicida and Y. ruckeri growth by PAA in vitro. The practical application of the products with high molecular PAA:H2O2 ratios should be prioritized if these pathogens are diagnosed.