Microplastic contamination in soils of urban allotment gardens (Toruń, Poland)

Abstract

Purpose: The study of microplastics (MPs) in soils is one of the most important contemporary challenges as they negatively influence soil properties and may adsorb heavy metals and pesticides. Recent data show that they can be transported in the terrestrial food chain, endangering human and animal health. In this pilot study, the qualitative–quantitative analysis of microplastics in soils of allotment gardens, which are mainly used for fruit and vegetable production, was done. Also, sources and environmental risks related to microplastics are discussed. Methods: We applied a four-step approach based on standard soil characteristics, density separation of MPs from the soil matrix, stereoscopic microscopy, and Fourier infrared spectrometry (FTIR). Results: In all studied topsoils, high abundance and heterogeneity of microplastics were found. Microplastics like polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polyurethane (PUR), phenolic resins (PF), and alkyd resins (AR) were identified. Their sources are not only related to human activities on the allotments, but also deposition with wind or water cannot be excluded. Conclusions: We revealed that soil contamination of microplastics in allotment gardens can be a significant environmental problem that has been overlooked in research. Considering the high amount of people who use allotment gardens and the potential environmental risk, soil contamination by microplastics should be monitored.