Rapid Assessment of Synthetic Fibers Released During Laundering Using Total Organic Carbon-Based Analysis

In this study, a total organic carbon (TOC)-based analytical method was proposed and applied to commercial textile products for the rapid and cost-effective quantification of synthetic fibers (as potential microplastic sources) released during the laundering process. Analysis of various commercial garments composed of blended fabrics, such as PET, nylon, cotton, and wool, revealed that the synthetic fiber emission per laundering was approximately 0.15 mg/g, showing high consistency with values reported in previous literature (0.03–0.31 mg/g). Notably, the proposed TOC-based method demonstrated a high recovery rate of 95.4–107.4% compared to the conventional gravimetric (balance) method, thereby validating its analytical reliability. Furthermore, based on these results, the influent loading to sewage treatment plants (STPs) was estimated, indicating that synthetic fibers originating from household laundering account for approximately 13.7% of the total microplastics in sewage. This finding aligns with the range reported in prior studies (5–17%), suggesting that laundering effluent is a major contributor to microplastic pollution in aquatic environments. Unlike conventional methods that consume several kilograms of textile products or samples, the TOC-based approach in this study enables rapid laundering, fiber recovery, and evaluation using only a few grams of samples. Consequently, this methodology is expected to serve as an efficient analytical tool for establishing feasible private-sector response strategies and government-led institutional guidelines aimed at reducing microplastic emissions from household laundering wastewater.