Effects of Peracetic Acid disinfectant on Daphnia Magna

FLORES, MARINA J.; GUTIERREZ, MARIA FLORENCIA; BERTOLA, GUIDO; BRANDI, RODOLFO J.; LABAS, MARISOL D.

Buenos Aires

Congreso; SETAC Latin America 11th Biennal Meeting; 2015

Society of Environmental Toxicology and Chemistry

Peracetic acid (PAA) is a strong oxidant and disinfectant. PAA is commercially available in the form of a quaternary equilibrium mixture containing: acetic acid (AA), hydrogen peroxide (HP), PAA and water. Due to its bactericidal, virucidal, fungicidal, and sporicidal effectiveness as demonstrated in various industries, the use of peracetic acid as a disinfectant for wastewater effluents has been drawing more attention in recent years. Some of the desirable attributes of commercial PAA are the ease of implementing treatment, small dependence of pH and the absence of production of significant amounts of toxic, mutagenic DBPs or chemical residual byproducts into effluents. The toxicity of peracetic acid can be explained by its oxidant activity. This oxidant activity and that of hydrogen peroxide can generate free radicals leading to oxidative stress in aquatic organisms. The hydroxyl radical activity of peracetic acid is lethal for bacteria and could be lethal for other organisms. The toxic potential of commercial peracetic acid, used also in the disinfection of urban wastewater, was evaluated with respect to an aquatic organism. Disinfection assays were carried out with freshwater from the city of Santa Fe (Argentina), and subsequently, toxicity bioassays were applied in order to verify possible adverse effects to the cladocerans (Daphnia magma). Daphnia magna was used due to its biology (reproduction by parthenogenesis which permits maintaining and breeding in the laboratory) and also because it is a zooplankton and thus a very important link in the freshwater food chain. Another reason for this choice was that this micro-crustacean is quite sensitive to pollutants in comparison to other freshwater invertebrates. Lastly, Daphnia seemed to be a good tool for our study since it is sensitive to detergents and disinfectant-detergent mixtures. The EC50 24-48 h (efficient concentration that immobilizes 50% of Daphnia after 24-48 h) were calculated by using Litchfield-Wilcoxon?s statistical method known as the ??probits method? where the LC/EC50 obtained was 0.466 mg/L of commercial peracetic acid. It would be interesting to complete this study with additional analyses. Indeed, the concentrations studied during an acute toxicity test and/or when the EC50 is calculated are far from environmental doses. Chronic toxicity tests at 21 days would permit studying the growth and reproduction of the study organism