Tracking Small Microplastics and Plastic Additives in Freshwater: An Integrated Analytical Approach

Microplastic (MP) and plastic additive (PA) pollution in freshwater systems threatens drinking water safety. This study proposes an integrated multi-analytical approach to characterize small microplastics (SMPs < 100 μm), PAs, and other microlitter components (MLCs) in a canal supplying a drinking water treatment plant. The method combines Micro-FTIR spectroscopy for particulate SMP and MLC identification with HPLC-Orbitrap for Non-Targeted Screening (NTS) and Suspect Screening Analysis (SSA) of dissolved PAs. Results showed the highest SMP abundance in Autumn (10,116 SMPs L−1), with 20 polymer types identified. Polytetrafluoroethylene (PTFE) was most abundant, followed by high-density polyethylene (HDPE); tire wear particles (TWPs) were also detected. Micro-FTIR identified antistatic agents, fillers, and lubricants as the main particulate PAs. SMPs averaged 57 μm in length and 32 μm in width. HPLC-Orbitrap revealed a predominance of plasticizers and flame retardants, specifically diethyl phthalate (DEP), dibutyl phosphate (DBP), tributyl phosphate (TBP), and tris(2-chloroethyl) phosphate (TCEP). Although EU regulations highlight the need to monitor MPs, specific regulatory limits and standardized treatment removal efficiencies remain undefined. This comprehensive assessment of particulate and dissolved fractions establishes a methodological framework to guide future safety standards and optimize water treatment.