ABSTRACT Hydrogen peroxide is widely used in water and wastewater treatment, particularly in advanced oxidation processes that aid in the degradation of compounds and microbial disinfection. Despite concerns about potential environmental contamination, its impact on freshwater ecosystems remains inadequately studied. Evaluating the ecotoxicity of aquatic organisms is crucial for establishing safe environmental concentrations. This study focuses on assessing the impact of hydrogen peroxide on the freshwater planarian Girardia tigrina , a regenerative invertebrate serving as an ecotoxicological model. Both acute and chronic effects were evaluated, including locomotion, regeneration, and reproduction. The LC 50 for 48 h was determined to be 123.55 mg/L. Sublethal exposure had minimal effects on locomotion, blastema regeneration, and fertility. Regeneration delays were observed at 3 mg/L, while fecundity was significantly affected at 1.52 mg/L. The planarians exhibited morphological abnormalities at the maximum quantity tested in the reproduction experiment (12.86 mg/L), which may have been the result of hydrogen peroxide‐induced mutations. In order to protect ecological health, this study advises keeping hydrogen peroxide levels below 1.52 mg/L and draws attention to the potential risks it poses to aquatic habitats. To guarantee complete environmental protection and a better knowledge of its effects, further research is needed.
Almeida et al. (Wed,) studied this question.