Plastic Dominates Developmental Toxicity Responses to Burn pit related Smoke in Zebrafish: Role for Polycyclic Aromatic Hydrocarbons

Abstract

Combustion of mixed materials during open air burning of refuse or housefires produces emissions that worsen air quality and may cause adverse health effects. Although previous studies have linked air pollution exposure from other sources to congenital defects, the potential developmental toxicity of mixed material combustion emissions remains uncertain. The purpose of this study was to compare the developmental toxicity of smoke derived from the combustion of 5 different material types (plywood, cardboard, plastic, mixture, and mixture plus diesel) in zebrafish larvae, a model often used to assess the behavioral and developmental effects of chemicals. Zebrafish have been shown to have similar physiological and biochemical responses to smoke exposure as other vertebrates and absorb chemicals (such as PAHs) through their epidermis from their surroundings. Larvae were exposed to organic extracts of each smoke at various concentrations and assessed for morphological and behavioral toxicity at 5 days post fertilization. All extracts caused concentration-dependent effects, including mortality, impaired swim bladder inflation, pericardial edema, spinal curvature tail kinks, or craniofacial deformities, although plastic and the mixture caused the most pronounced effects. Plastic also altered locomotor responsiveness to light changes to the greatest extent. Interestingly, some morphological and behavioral responses correlated strongly with total and specific polycyclic aromatic hydrocarbons concentrations in the smoke extracts. Overall, the findings suggest that material type and combustion chemistry impact the severity of developmental toxicity of mixed material smoke in zebrafish.