A study carried out in China has investigated the link between exposure to polymers (a group of compounds found in certain plastics) and sperm quality in individuals without occupational exposure to these materials.
“Microplastics are ubiquitous environmental contaminants that have been detected in human semen from polluted areas, yet their prevalence and effects in the general population remain largely unexplored,” stress the authors of the work.
To find out more about the potential amount of microplastics present in human semen, and to try to determine the extent to which this may interfere with male fertility, the researchers analysed semen samples from 36 healthy adult men, collected during premarital health assessments.
In laboratory tests, the researchers detected microplastics in all the semen samples studied, with at least two particles per sample. Eight types of polymers were identified, including polystyrene (PS), polyethylene (PE) and polyvinyl chloride (PVC).
The study recorded a difference in sperm motility, which may vary according to the type of plastic. Sperm exposed to polystyrene, for example, showed higher progressive sperm motility than those exposed to polyvinyl chloride.
Sperm morphological abnormalities were also observed, but were not significantly associated with specific types of plastic.
“The effects of exposure to different microplastic polymers on sperm progressive motility varied, which underscores the need for further investigation into how microplastics affect male fertility in terms of their pervasive presence and potential reproductive toxicity,” the researchers conclude.
This isn’t the first study to detect microplastics in human semen. An article published in May in the journal Toxicological Sciences refers to analyses carried out in New Mexico (USA) on 23 samples of male semen.
Six months earlier, Italian researchers explained (in another study) that they had found fragments of pigmented microplastics with spherical or irregular shapes in six out of ten human semen samples.