Parental exposure to plasticizers in treated sewage effluent induces life stage-dependent neurotoxicity in zebrafish F1 offspring

Plasticizers are persistent contaminants commonly detected in treated sewage effluent (TSE), which has raised concerns regarding their potential neurotoxic effects in exposed aquatic species. This study examined the neurobehavioral and molecular impacts of chronic exposure to environmentally relevant concentrations of plasticizer-contaminated TSE in adult zebrafish and their offspring. Adult zebrafish were chronically exposed for three months to TSE collected from three wastewater treatment stations (A, B, C) . Locomotor, expression of key neurodevelopmental as well as genes involved in oxidative stress and apoptosis were evaluated in both adults and embryos to assess life stage–specific and parental exposure-mediated responses in F1 offspring. TSE analysis revealed station specific plasticizer mixtures, with the highest cumulative concentrations detected at Station A . These chemical differences preceded distinct biological effects. Adult zebrafish exhibited significant hyperactivity across stations, while embryos from exposed adults showed reduced motility, strongest for Station B . Gene expression analysis showed station dependent alterations in neurodevelopmental, oxidative stress, and apoptotic markers, with adults displaying overall downregulation of neuronal genes and offspring exhibiting increased neurotrophic and stress related responses. These findings suggest that chronic exposure to environmentally realistic plasticizer mixtures in TSE is associated with life stage-dependent neurotoxic responses and parental exposure-mediated molecular alterations in F1 offspring; however, causal attribution to specific compounds cannot be established from these mixture-based data. These findings highlight the need for mixture aware risk assessment and sustained monitoring of reclaimed water quality in water scarce regions. • Real-world treated sewage effluent (TSE) contains multiple plasticizers including DBP and DiNP, DEP, DiBP, and DEHP. • Adult zebrafish exposed to TSE exhibit hyperactivity; embryos show hypoactivity. • Gene expression profiling reveals life stage–specific neurotoxicity and compensatory responses. • Intergenerational effects observed in zebrafish offspring following parental TSE exposure. • Findings support mixture-based risk assessment and improved monitoring of reclaimed water.