Identification and Quantification of Microplastics in Commercial Compost From a Wide Range of Composting Materials and Potential Environmental Impacts

Abstract

Microplastic pollution in commercial compost has the potential to be a new source of contamination for agricultural land; however, until now, there have been no studies that directly compare microplastic contamination in compost based on the variety of raw materials and link them to their ecological risk levels. This study aims to identify and quantify microplastics in various types of compost derived from household waste, livestock manure, and vegetable straw. The methods used include extraction of microplastics with an acid solution, particle filtration using micron filters, and identification of morphologies and polymers through stereo microscopy and FTIR (Fourier-transform infrared) spectroscopy. The results showed that all types of compost contained microplastics, with the highest abundance in compost mixtures of manure and goat manure (11 particles/kg). Microplastics are dominated by polyethylene and polypropylene polymers, with fiber and filament shape measuring < 2 mm, and most samples are in the high-risk category (Level IV). The conclusion of this study is that commercial compost has the potential to be a major vector for the entry of microplastics into soil ecosystems. These findings have a significant impact on waste management and the safety of compost use in sustainable farming practices.