Acute and Chronic Toxicity of Prothioconazole and its Metabolite Prothioconazole-Desthio To Daphnia Magna

Abstract Prothioconazole (PTC) is a broad-spectrum triazole fungicide. Current research has mainly focused on its efficacy and residues, with few studies on its toxicological effects. This study assessed the effects of PTC, and its metabolite prothioconazole-desthio (PTCd), on the inhibition of activity, growth, and reproduction of Daphnia magna using acute and chronic toxicity tests. Additionally, the dose-response relationship was established to determine sensitive biological indicators. The acute toxicity test shows that the 48 h EC50 of PTC and PTCd to D. magna were 2.82 and 5.19 mg/L, respectively. The chronic toxicity of PTC and PTCd to D. magna were 0.00860 and 0.132 mg/L, respectively, with the parent compound being 15.3 times more toxic than its metabolite. The acute to chronic toxicity ratio (ACR) was calculated using chronic toxicity data, with ACR values of 227 and 27.5 for PTC and PTCd, respectively. These results indicate that both PTC and PTCd affect the growth and reproduction of D. magna, and the toxicity of the parent compound is greater than that of its metabolite. In conclusion, the metabolites of this pesticide have sufficient toxicity to harm D. magna at relevant environmental concentrations, and their environmental risk should not be neglected.