Raman Microspectroscopy Evidence of Microplastics in Human Semen: An Emerging Threat to Male Fertility

Abstract

The presence of microplastics (MPs) in human fluids and organs is a great concern, since, as highlighted by recent studies on animal models, they could cause alterations of several physiological functions, including reproduction. In this study, N. 10 semen samples collected from men living in a polluted area of the Campania Region (Southern Italy), were analyzed by Raman Microspectroscopy to evaluate the presence of MPs and to characterize them in terms of morphology (size, color, and shape) and chemical composition. In total, N. 16 pigmented microplastic fragments (ranging from 2 to 6 μm in size) with spheric or irregular shapes were found in six of ten samples. Chemical composition showed the presence of polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), polystyrene (PS), polyvinylchloride (PVC), polycarbonate (PC), polyoxymethylene (POM) and acrylic, suggesting ingestion and/or inhalation as a route of exposure to environmental MPs. In this work, we propose for the first time a mechanism by which MPs pass into the semen most probably through the epididymis and the seminal vesicles, which are the most susceptible to inflammation. Given the global decline in seminal quality in recent decades, action is therefore needed to stop the exponential increase in plastic waste as it impacts the reproductive process.

Keywords: Microplastics, human semen, epididymis, seminal vesicles, Raman Microspectroscopy