Neurotransmission disruption in wild Chirostoma jordani from Lake Zumpango linked to alkylphenols and their derivatives.

Alkylphenols (APs) and their ethoxylates (APEs) are endocrine disruptors found in aquatic environments. This study evaluated the neurotoxic effects of bisphenol A (BPA), 4-nonylphenol (4-NP), and 3-tert-butylphenol (tertBP) in wild Mezquital silverside (Chirostoma jordani) from Lake Zumpango across dry, rainy, and cold-dry seasons. Biomarkers analyzed included acetylcholinesterase (AChE), carboxylesterase (CbE), butyrylcholinesterase (BChE), and γ-aminobutyric acid (GABA) levels in brain and spinal cord. Results showed seasonal and tissue-specific differences in enzymatic activities correlating with AP and APE concentrations. BChE and CbE activities were elevated during the dry season, associated with higher 4-NP sediment levels and lower BPA and tertBP in water. AChE activity and GABA levels peaked in the rainy season when tertBP was absent. Total phenols fluctuated seasonally but showed no clear neurotoxic association. These findings provide initial evidence of neurotoxic disruption in wild Mezquital silverside by BPA, 4-NP, and tertBP, warranting further ecotoxicological investigation.