Microplastics in Kidney Stones: A Preliminary Component of an Integrated One Health Investigation

The widespread presence of microplastics (MPs) has emerged as a major One Health concern due to their increasing detection in human tissues and biological fluids. Within an integrated One Health research program, analytical workflows were developed to detect MPs across biological matrices. Kidney stones represent an unexplored pathological biomineral that may preserve evidence of long-term exposure. This pilot study evaluated the application of a Fourier-transform infrared microspectroscopy (µ-FTIR) workflow for detecting MPs in human kidney stones. Sixty kidney stone samples were examined for MPs. Suspected particles identified by stereomicroscopy were chemically characterized by µ-FTIR. Particles were detected in 8 of 60 kidney stone samples. µ-FTIR analysis identified confirmed polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), and polyurethane (PU) particles. Additional particles showed absorption bands compatible with polyvinyl chloride (PVC). This study demonstrates the applicability of a µ-FTIR workflow for detecting MPs in pathological biominerals and provides preliminary evidence of their presence in kidney stones. These findings support the use of kidney stones as a novel matrix for One Health biomonitoring and provide a methodological basis for future studies integrating urine, organoids, and multi-omics approaches to investigate the biological significance of microplastic exposure.