Emission characteristics analysis on microplastics by inorganic sludge discharged from recycling processes of agricultural waste vinyl in Korea

Globally, various policies are being implemented to phase out plastic, and South Korea has set targets to reduce waste and increase recycling rates by 2030. Concerns about managing microplastic pollution are growing. Most advanced research has primarily focused on aquatic ecosystems. This has left a gap in data on residues in sludge generated from agricultural waste recycling processes. Therefore, environmental analysis (leaching tests, heavy metal and microplastics content, etc.) was carried out using the inorganic sludge discharged from the agricultural waste recycling process to establish national data for various environmental analyses in this study. Specifically, inorganic sludge was selected as a sample from the agricultural waste recycling process since it would be recycled as a filling or covering material in agricultural soil. Therefore, this study analyzed and assessed the content of harmful substances and microplastics in the inorganic sludge generated from agricultural waste recycling processes. As a result, it was revealed the detection of unregulated items such as Al (leaching: 1.54 mg/L, content: 23,870 mg/kg), Fe (leaching: 0.48 mg/L, content: 27,453 mg/kg), and Mn (leaching: 0.06 mg/L, content: 649 mg/kg). Among regulated items, Cu (35.96 mg/kg), Ni (8.77 mg/kg), Pb (6.47 mg/kg), and Zn (178.39 mg/kg) were detected within the legal concentration limits. As for microplastics, the number (1814 particles) and mass (446.54 μg/g) were detected. However, the impact of microplastics is not identified clearly yet. Therefore, if the study results and subsequent accumulation of data by expanding the research target waste can be utilized, it is expected that this could serve as fundamental data for establishing policies or legislation for microplastic management systems.