Developmental and neural toxicity of the dinitroaniline herbicide pendimethalin in zebrafish early-life stages

Pendimethalin (PND) belongs to the dinitroaniline family of herbicides and is commonly used to control broadleaf weeds, but its persistence in the environment and potential toxicity have become a growing concern. This study investigated the sublethal effects of PND on early development of zebrafish. Three sublethal concentrations (0.2, 1, and 2μM) were administered to early-life stages in a semi-static system for 120 hours post-fertilization (hpf). Internal concentrations were measured via UHPLC-HRMS, showing significant bioaccumulation (up to 1.17 mM at 1 μM). Morphometric analysis at 120 hpf revealed reduced body length, eye area, and swim bladder size, especially at higher concentrations. Behavioral assays indicated impaired locomotor activity, with reduced swimming distance, duration, and velocity in visual motor response (VMR) tests. Electrophysiological recordings of local field potentials (LFPs) in the forebrain revealed seizure-like activity, marked by increased event duration and power. These findings highlight PND’s potential developmental and neurotoxic effects in aquatic vertebrates and raise concerns about its broader ecological and human health implications due to bioaccumulation and environmental persistence.