Microplastics in human semen: Physicochemical characterisation and surface-associated elemental profiles among...

Microplastics are increasingly recognised as pervasive environmental contaminants with the capacity to interact with biological systems. Beyond intrinsic particle properties, their heterogeneous surfaces may co-occur with exogenous chemical constituents, yet human evidence describing the physicochemical characteristics of microplastics within the male reproductive system remains limited. This cross-sectional descriptive human biomonitoring study characterised the occurrence, polymer composition, morphology and surface-associated elemental profiles of microplastics isolated from human semen. Semen samples were collected from 115 Malaysian men aged 18-45 years and analyzed using Raman microspectroscopy for polymer identification, followed by Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) spectroscopy for morphological assessment and qualitative elemental characterisation. Microplastics were detected in all samples, with concentrations ranging from 0.2 to 3.3 particles/mL and particle sizes between 4 and 27 μm. Polypropylene and polyethylene terephthalate were the predominant polymers identified. The SEM-EDX analysis demonstrated heterogeneous surface-associated elemental profiles, including phosphorus, calcium, iron, copper, mercury and titanium, which are reported here as qualitative surface co-occurrence rather than confirmed adsorption or biologically available fractions. Within this descriptive framework, the present study does not assess transport mechanisms, desorption kinetics or reproductive health outcomes. This work therefore provides baseline physicochemical characterisation of semen-derived microplastics within a sensitive human biomonitoring matrix. These findings highlight the compositional complexity of microplastics in semen and underscore the need for future studies combining quantitative elemental analysis, nano-scale detection, and reproductive functional endpoints to better understand their potential biological relevance.