Acute toxicity of atrazine degradation solutions via advanced oxidation processes: An experimental and in-silico approach based on mass spectrometry data.

Although atrazine has been banned, residues of the compound and its metabolites are still detected in certain areas of French groundwater. In response to the European Green Deal, this study focuses on the degradation of atrazine in tap water and the toxicological evolution of different treatments. The degradation efficiency of atrazine in deionized water by high-voltage electrical discharge (HVED) and high-frequency ultrasound (HFUS) was higher than that in tap water with the same initial atrazine concentration, likely due to competition from impurities in tap water, such as ions and other organic compounds. Additionally, acute toxicity testing using Daphnia magna was conducted to assess the toxicological impact of the degradation processes. Acute toxicity (LC50) values were used to evaluate the toxicity of the different treatment solutions initially containing atrazine. High-resolution mass spectrometry coupled with liquid chromatography (LC-HRMS) was employed to identify and compare the transformation products generated by each degradation technique. Furthermore, an in-silico toxicity evaluation using the QSAR model was proposed and compared to the experimental data. The in-vivo assessment revealed that atrazine solutions treated with Fenton oxidation (LC50 < 0.1 mg/L) were significantly more toxic than those treated with HFUS (LC50 > 5 mg/L) or HVED (1.5 < LC50 < 2.5 mg/L). However, in the in-silico evaluation, Fenton oxidation appeared less toxic, as residual toxicity from ferrous ions and hydrogen peroxide was not considered. Consequently, the degradation of atrazine by HVED and HFUS proved to be more efficient and environmentally favorable.