Black Carbon, Oxidative Potential, and Zebrafish Toxicity: A Toxicological Study of PM2.5 in Tennessee.

Fine particulate matter (PM_2.5) is a threat to human health and varies by location. PM_2.5 can cause oxidative stress, leading to serious health outcomes, especially during development. Additionally, black carbon (BC), a PM_2.5 component, is associated with developmental issues. This study analyzes the oxidative potential (OP) of PM_2.5 and utilizes zebrafish to analyze the developmental impacts of PM_2.5collected in 2 months from four locations in Tennessee. BC analysis was conducted on collected filters, while OP analysis was performed using the dithiothreitol (DTT) assay on extracted PM_2.5. The extracted PM_2.5 (pooled based on months and locations) and controls (vehicle, field blank) were used for developmental exposures in zebrafish (n = 33/treatment group). PM_2.5 and BC trended positively, and BC contribution in PM_2.5 ranged from 6% to 36%. There were no significant differences between sampling locations across months for PM_2.5 or BC. However, OP differed across locations and months, with significant differences between months at three out of our four locations. Zebrafish morphology was not altered following exposure to PM_2.5, but significant differences in the swim distances were observed between treatments and control groups as well as between PM_2.5-treated groups from different locations and months. The findings from this research provide insight into the oxidative and developmental effects of exposure to PM_2.5 and its components to ultimately support air pollution risk assessments incorporating mechanistic effects and subclinical biomarkers.