Toxicity of ametryn and clomazone in zebrafish: Environmentally relevant concentrations induce developmental and enzymatic alterations

Ametryn (AMT) and clomazone (CLZ) are widely used for weed control, often in combination. This study evaluated the effects of environmentally relevant concentrations of AMT, CLZ, and their mixtures on zebrafish embryonic-larval development and enzyme activity. Exposure to AMT (≥0.1 µg/L) and CLZ (≥36 µg/L) significantly reduced swim bladder inflation, although their mixture showed an antagonistic effect, minimizing damage. Both herbicides reduced acetylcholinesterase (AChE) activity, an effect observed from the lowest concentrations tested, indicating neurotoxicity, while the mixture mitigated this effect. Aspartate aminotransferase (AST) activity increased from 6 µg/L AMT and 20 µg/L CLZ, and alanine aminotransferase (ALT) activity increased from 3.7 µg/L AMT and 6 µg/L CLZ, suggesting hepatotoxicity. Alkaline phosphatase (ALP) activity increased with 3.7 µg/L AMT and 6 µg/L CLZ. The mixture modulated enzyme alterations and increased damage at specific concentrations. Overall, AMT and CLZ exposure impaired development and altered enzyme function, causing neurotoxic and hepatotoxic effects.