Microplastics in every human semen, sperm motility at risk: Study

Researchers have found microplastics in the every semen samples they tested. Chinese public health researchers from various institutions questioned whether ingested microplastics might be contributing to the global decline in fertility rates.

They collected semen samples from 36 healthy adult males, who were living in China’s eastern part, Jinan. All participants, who were not linked to plastics industry, provided a sample of semen for testing.

The researchers aimed to examine the presence, abundance, and types of microplastic polymers, as well as their relationship with semen quality parameters, in individuals without occupational exposure to plastics.

Raman microspectroscopy was employed to identify, quantify, and categorize microplastic polymers. Sperm motility was assessed via computer-assisted analysis, while morphology was evaluated through Diff-Quik staining, according to the study.

Eight distinct polymers were identified

Researchers detected microplastics in all semen samples, with an average of two particles per sample (ranging from 0.72 to 7.02 μm). Eight distinct polymers were identified, with polystyrene (31 %) being the most prevalent.

Semen exposed to polystyrene demonstrated higher sperm progressive motility compared to the polyvinyl chloride exposure group, the researchers claimed.

While sperm morphological abnormalities were observed, they were not significantly associated with specific plastic types, according to the study.

Lower sperm motility

Researchers also found lower sperm motility in samples that contained polyvinyl chloride plastic bits, a key observation that could help explain the decline in fertility rates.

From the depths of the world’s oceans to the upper atmosphere, microplastics are found almost everywhere. Previous research has suggested that the average person consumes about one credit card’s equivalent of plastic each week.

Plastics can enter human body in multiple ways

Plastics can enter the body in multiple ways, such as drinking from plastic bottles, inhaling airborne particles, or eating food heated in plastic containers. The researchers further note that it is now virtually impossible for people to avoid ingesting microplastics, reported Medical Express.

The researchers said that the effects of exposure to different microplastic polymers on sperm progressive motility varied, which underscores the need for further investigation into how microplastics, with their widespread presence and potential reproductive toxicity, affect male fertility.

Impact on human health

According to WHO, the potential hazards associated with microplastics come in three forms: physical particles, chemicals, and microbial pathogens within biofilms. Based on the limited evidence available, chemicals and biofilms associated with microplastics in drinking water pose a low concern for human health.

However, there is insufficient information to draw definitive conclusions about the toxicity related to the physical hazard of plastic particles, particularly for nano-sized particles.

The UN health agency previously maintained that studies on absorption indicate that microplastics larger than 150 µm are likely to be excreted directly through feces. The uptake of smaller particles is expected to be limited, although the absorption and distribution of very small microplastic particles, including nanoplastics, may be higher.

The WHO had earlier said that toxicology studies in rats and mice reported some impacts, including liver inflammation. However, these few studies are of questionable reliability and relevance, with findings reported at very high exposures that would not occur in drinking water.

The study was published in the journal Science of the Total Environment.