Assessment of Microplastic and Pollutant Leaching in Waste Plastic-Modified Asphalt Concrete

Abstract: This research aims to investigate the potential generation of microplastics and the leaching behavior of waste plastic-modified asphalt concrete (AC). Leaching is defined as the partitioning of pollutants from waste solids into the surrounding liquid medium. The Toxicity Characteristic Leaching Procedure (TCLP; US EPA Method 1311) will be employed to simulate water run-off toxicity and microplastics leaching from plastic-modified AC. This method can determine both organic and inorganic elements in liquid, solid, and multiphasic waste. Samples will be prepared using waste Low-Density Polyethylene (wLDPE), Styrene-Butadiene-Styrene (SBS), and control AC. The leachate solution will be collected and filtered to remove suspended particles, and both the solution and suspended particles will be analyzed using inductively coupled plasma mass spectrometry (ICP-MS). ICP-MS can determine major and minor trace element (TE) concentrations. The TE list is defined based on common uses in plastic production, such as fillers, biocides, antioxidants, catalysts, and pigments. Results will be compared for plastic-modified AC, polymer-modified AC, and control AC against US EPA Maximum Contaminant Levels (MCL) and Secondary Maximum Contaminant Levels (SMCL) for drinking water. The study will provide a comprehensive understanding of the environmental impact of using waste plastics in AC.
Keywords: TCLP, TE, wLDPE, SBS, ICP-MS, MCL, and SMCL.