The COVID-19 outbreak has significantly raised the amount of single-use mask waste in Indonesia. This research intends to assess the effect of single-use mask waste on the quality of loamy soil. The investigation involved constructing a prototype using a 28-cm high column of 19 cm of loamy soil. The study utilized single-use masks in the soil, in which Chili plants were grown on the soil surface. Clean water was employed for the leaching process over 45 days. Soil samples from control, R1, R2, and R3 reactors were analyzed in the laboratory using X-ray Fluorescence (XRF) testing and microplastic identification in groundwater. The research findings reveal a notable decline in macro and micronutrients, namely a 1.22% decrease in silicon minerals caused by microplastics interfering with plant metabolic processes. The increase in microplastics caused higher microorganism mortality, leading to a 10.18% decrease in organic carbon content and a 1.47% reduction in soil porosity. Microplastics were discovered in the loamy soil of an average size of 0.3±1.34 mm. Changes in nutrient concentrations and physical properties of the soil indicate that introducing microplastics into loamy soil through mask waste can alter soil characteristics. Additional research is required to investigate the disposal of single-use mask waste due to the ongoing high utilization of disposable masks as personal safety equipment.