Dioctyl phthalate (DOP), a widely used plasticizer in flexible plastics, was evaluated for acute toxicity in zebrafish (Danio rerio) embryos and adults as a vertebrate model. Embryos were exposed to 1.0–300 mg/L DOP following OECD guideline 236, and adults were assessed under OECD guideline 203 at concentrations range of 1- 600 mg/L. Embryonic exposure at ≥100 mg/L produced significant developmental abnormalities, including pericardial edema, spinal deformities, and delayed hatching, with 100% mortality at 200 mg/L. In adults, at concentrations above 400 mg/L of DOP complete mortality within 24 hours was observed, and histopathology demonstrated dose-dependent injury in the liver, kidney, and testes; notably, 400 mg/L induced fatty liver changes, renal tubular necrosis, and oligospermia. The median lethal concentration (LC50) values obtained in this study were 238 mg/L for adult zebrafish and 126 mg/L for larvae, indicating higher sensitivity in early life stages. Collectively, these results demonstrate severe, dose-dependent acute toxicity of DOP across developmental stages and underscore the need for regulatory measures to limit its use and to prioritize safer alternatives in consumer and medical products.
Rezazadeh et al. (Mon,) studied this question.