Particulate toxic elements' oxidative potential and gastrointestinal bioaccessibility features in the vicinities of coal-fired mineral processing industries, India.

Abstract

Particulate matter (PM) poses significant health risks due to its ability to generate reactive oxygen species (ROS) and transport toxic metal(loid)s into the human body. In this study, an in vitro physiologically based extraction test (PBET) method, allowing the simulation of the gastric phase (GPh) and intestinal phase (IPh) of human digestion, was applied to evaluate bioaccessibility of eleven potentially toxic elements (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in airborne particulate matter (APM) samples collected from an urban-residential area in Chhattisgarh, India. Additionally, oxidative potential (OP) was assessed using the dithiothreitol (DTT) assay for a comprehensive understanding of PM toxicity. The bioaccessibility of metal(loid)s varied significantly across phases, with gastric phase solubility upto ~ 75%, attributed to its lower pH enhancing metal dissolution. Elevated DTT responses were recorded for PM₁₀ and PM_2.5, driven primarily by Fe, Zn, and Pb, underlining their pivotal role in oxidative stress generation. Correlation analyses demonstrated strong associations between bioaccessible fractions and OP, especially in the GPh. The findings advance understanding by linking bioaccessibility with ROS generation and highlight the importance of particle size and solubility in assessing the health risks posed by PM. These insights provide a foundation for improved risk assessments and mitigation strategies targeting emissions from high-temperature processing industries, and vehicular activities, on a global scale.