The Detection of Forever Chemicals from Paper Cups using Colorimetry

Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals added to food packaging products to increase water-resistance and durability. PFAS are a growing concern due to their migration into beverages and foods and have been linked to cancer, immunotoxicity, and thyroid disturbances. The purpose of this study was to quantify PFAS migration from paper cups into water and evaluate toxic effects using planarians. PFAS detection was performed using a colorimetric assay, which forms a colored complex with PFAS, on: perfluorononanoic acid (PFNA), heptadeca fluorooctane sulfonic acid potassium salt (PFOS), perfluorooctanoic acid (PFOA). PFNA and PFOS showed absorbance at 640 nm, while PFOA showed absorbance at 626 nm. Detection limits for this method ranged from 0.373 μg/mL to 5.19 μg/mL, demonstrating the method quantified PFAS at low levels. Overlapping absorption peaks limit distinguishing between PFAS compounds, making the method more suitable for quantification of overall PFAS content rather than identification. PFAS were detected in both paper cup types examined across temperatures (24.2°C, 45°C, and 65°C), particularly, high concentrations at elevated temperatures; however, no statistically significant differences were observed. Higher concentrations were observed at elevated temperatures, but these differences were not statistically significant. Planarians (Girardia dorotocephale) were exposed to PFOA and paper cup extracts to assess toxicity though behavior and survival, serving as a sensitive model for detecting neurotoxic and lethal effects. An overall effect of PFOA concentration was observed at five-hours; however, Tukey post hoc analysis did not identify differences between concentrations. When compared to cup extracts, a difference occurred at 15 minutes, where the PFOA group showed reduced behavior compared to the control. No significant differences were observed at later time points, and no mortality occurred. Variability within groups likely limited detection. These results indicate that exposure time had a greater influence on behavior than concentration, and PFAS exposure produced sublethal behavioral effects rather than lethal toxicity.