Burn pit-related smoke causes developmental and behavioral toxicity in zebrafish: Influence of material type and emissions chemistry

Combustion of mixed materials during open air burning of refuse or structural fires in the wildland urban interface produces emissions that worsen air quality, contaminate rivers and streams, and cause poor health outcomes including developmental effects. The zebrafish, a freshwater fish, is a useful model for quickly screening the toxicological and developmental effects of agents in such species and elicits biological responses that are often analogous and predictive of responses in mammals. The purpose of this study was to compare the developmental toxicity of smoke derived from the burning of 5 different burn pit-related material types (plywood, cardboard, plastic, a mixture of the three, and the mixture plus diesel fuel as an accelerant) in zebrafish larvae. Larvae were exposed to organic extracts of increasing concentrations of each smoke 6-to-8-hr post fertilization and assessed for morphological and behavioral toxicity at 5 days post fertilization. To examine chemical and biological determinants of toxicity, responses were related to emissions concentrations of polycyclic hydrocarbons (PAH). Emissions from plastic and the mixture containing plastic caused the most pronounced developmental effects, including mortality, impaired swim bladder inflation, pericardial edema, spinal curvature, tail kinks, and/or craniofacial deformities, although all extracts caused concentration-dependent effects. Plywood, by contrast, altered locomotor responsiveness to light changes to the greatest extent. Some morphological and behavioral responses correlated strongly with smoke extract levels of PAHs including 9-fluorenone. Overall, the findings suggest that material type and emissions chemistry impact the severity of zebrafish developmental toxicity responses to burn pit related smoke. 

Impact/Purpose

The combustion of mixed materials in open air burning of refuse and housefires produces emissions that worsen air quality and contaminate rivers and streams. Additionally, smoke from biomass burns, which often include emissions from structural fires especially in the wildland urban interface, have been associated with mortality and poor health outcomes including developmental effects. Freshwater organisms are often exposed to smoke from watershed runoff, ash deposits, or other forms of contamination making the zebrafish, a freshwater fish, a useful model for quickly screening the toxicological and developmental effects of smoke in such species. Furthermore, zebrafish biological responses to chemical agents are often analogous to and predictive of responses to the same agents in mammalian models. Thus, the present findings may increase understanding of the ecotoxicological and biological impacts of a key contemporary air pollution source (i.e., mixed material burns) and shed light on the influence of material type and combustion chemistry on such responses. This product will describe the morphological and behavioral impacts of developmental exposure to PM from five different combusted burn pit-related fuel types (i.e., plastic, cardboard, wood, mixture, and mixture + diesel fuel) in zebrafish.  

Citation

Smoot, J., S. Padilla, Yong Ho Kim, D. Hunter, A. Tennant, B. Hill, M. Lowery, B. Knapp, W. Oshiro, M. Hazari, M. Hays, William Preston, I. Jaspers, Matthew Gilmour, AND A. Farraj. Burn pit-related smoke causes developmental and behavioral toxicity in zebrafish: Influence of material type and emissions chemistry. Elsevier B.V., Amsterdam, NETHERLANDS, 10(8):e29675, (2024). [DOI: 10.1016/j.heliyon.2024.e29675]

DOI: Burn pit-related smoke causes developmental and behavioral toxicity in zebrafish: Influence of material type and emissions chemistry