Subchronic Exposure to Nonylphenol Ethoxylate at Environmentally Relevant Level Promotes Mutagenic, Neurotoxic, and Pro-oxidant Effects in Bullfrog Tadpoles

Abstract

Nonylphenol compounds released into aquatic environments have been shown to exert deleterious effects on aquatic organisms. Amphibians, particularly during larval stages, are highly vulnerable to chemical stressors and are chronically exposed to pollutants such as nonylphenol ethoxylate (NPE). This study evaluated the sublethal effects of environmentally relevant concentrations of NPE (30 µg L −1 ) under sub-chronic exposure in Aquarana catesbeiana tadpoles (Gosner stage 25), with emphasis on mutagenic, neurotoxic, and oxidative responses. The analyses included blood cell composition, frequency of micronuclei (MN) and erythrocytic nuclear abnormalities (ENAs), acetylcholinesterase (AChE) activity in brain and muscle tissues, and oxidative stress biomarkers (lipid peroxidation and protein carbonylation) in blood. Results demonstrated that NPE exposure induced clastogenic and aneugenic effects in erythrocytes, impaired central and muscular cholinergic function, and triggered oxidative stress in blood. These findings highlight the NPE potential to disrupt critical physiological systems in amphibians.

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