The health effects of plastic burning particulate matter- the role of metals, Polycyclic aromatic hydrocarbons, environmentally persistent free radicals, reactive oxygen and chlorine species in inducing oxidative stress in human body

Plastic burning can significantly contribute to the overall particulate matter (PM) burden in developing countries, where inadequate waste management and low public awareness often result in open refuse burning. However, their chemical composition and health-related properties are largely unelucidated. In this study, we generated PM through controlled combustion of five widely used plastic materials. Our findings reveal that metals and polycyclic aromatic hydrocarbons (PAHs) detected in the plastic samples may drive oxidative stress through ROS formation. We observed significant quantities of EPFRs and ROS in the aqueous extracts of the PM. Additionally, plastic burning PM showed excessively high levels of reactive chlorine species (RCS). The oxidative potential, a key metric for PM toxicity, was assessed using acellular assays- OP-DTT and OP-OH. A kinetic box model was employed to simulate OP-OH, focusing on the rate of hydroxyl radical (•OH) formation. The model integrated reactions involving PAHs, metals, EPFRs, ROS, and RCS, using rate constants from established literature. It reasonably predicted •OH formation rates for the five types of plastics tested. Our results suggest that radical production is driven by complex chemical mechanisms, including redox cycling of active components, ROS cycling, Fenton chemistry, and organic oxidation reactions. Given the widespread use of plastics and growing environmental concerns around plastic pollution, this study highlights the urgent need for stricter regulations and improved waste management practices, especially in developing countries. Further details will be presented.