Toxicological Bioassays on the Native Microalga Dictyosphaerium sp. as a Possible Phycoremediator Against Relevant Pesticides

MARIBEL RAY; JORGELINA DARUICH; CANDELA ALGOZINO; AGOSTINA CORTEZ; AGUSTINA JORQUERA; DANA MUÑOZ; ELBA QUAIFE; CESAR ALMEIDA; PATRICIA GONZALEZ; STELLA MARIS DA SILVA; MATIAS FUNES; JUAN MANUEL PEREZ IGLESIAS

Congreso; SETAC Latin America 15th Biennial Meeting; 2023

Input of xenobiotics into the aquatic environment can cause an imbalance by altering the communities that inhabit. Microalgaes are the producer community and this is why they are the first to be exposed to environmental changes and respond to this. On the other hand, it is known that in neotropical regions the most widely used pesticides are the herbicide glyphosate (GLY) in a cocktail with new-age insecticides such as chlorpyrifos (CLO) and/or imidacloprid (IMI). In this sense, this work aimed to evaluate the response of a native algae (Dictyosphaerium sp.) against the exposure of three widely used pesticides: GLY, IMI and CLO in a range of five concentrations between 5 to 100 μg GLY/L, 1 to 20 μg IMI/L and 10 to 100 μg CLO/L. Acute toxicity bioassays (96h) were carried out placing an initial cell density of a microalgae strain of 1.6 x 106 cells/mL, by triplicate. As toxicity endpoints, algal growth (by Neubauer chamber), chlorophyll-a and catalase activity were evaluated. The results obtained showed that the microalgae cultures had an averageincrease in growth of 18%, 16% and 15% for GLY, CLO and IMI, respectively. No significant differences were observed in chlorophyll-a concentrations between the treatments and the control. Catalase activity revealed significant increases in the highest concentrations of insecticides. In the case of GLY, catalase activity decreased with increasing herbicide concentrations. It should be noted that, for the first time, different physiological biomarkers are evaluated in native algae isolated from pure strains from arid regions in the presence of contaminants such as pesticides. On the other hand, in previous studies carried out by the working group, we demonstrate the ability of this algal species to reduce the presence of these pesticides was demonstrated in bioassays on a pilot test. In this context, and adding these new results where algal growth and enzymatic response are observed, this work demonstrates the potential phycoremedial use of a native algae against possible contamination by widely used pesticides.