Microplastic contamination was found in all human semen samples tested in a study, and researchers say further research into the potential harm to reproduction is “essential”.
Sperm counts in men were falling for decades and 40% of low scores remain unexplained, though chemical pollution is implied by many studies.
The 40 semen samples were from healthy men who underwent premarital health assessments in Jinan, China. Another recent study found microplastics in the semen of six out of 10 healthy young men in Italy, and another study in China had the pollutants in it half of 25 samples.
Recent studies in mice have reported that microplastics decreased sperm count and caused abnormalities and hormone disruption.
Research on microplastics and human health is moving fast and scientists seem to be finding the contaminants everywhere. The pollutants were found in all 23 human testis samples tested in a study published in May.
Microplastics have also recently been discovered in human blood, placentas and Breast milk, indicating widespread contamination of people’s bodies. The impact on health is still unknown, but microplastics are shown to cause damage to human cells in the laboratory.
Millions of tonnes of plastic waste are dumped into the environment and much is broken down into microplastics. It polluted the entire planet, from the summit of Mount Everest after the deepest oceans. Humans are known to ingest the small particles via food and water as well as breathe them in.
“As emerging research increasingly implicates microplastic exposure as a potential factor affecting human health, it is imperative to understand the extent of human contamination and its relationship to reproductive outcomes,” said Ning Li, of Qingdao University in China, and colleagues.
“[Mouse studies] show a significant decrease in viable sperm count and an increase in sperm deformities, indicating that microplastic exposure may pose a chronic, cumulative risk to male reproductive health.
The research, published in the journal Science of the total environment, detected eight different plastics. Polystyrene, used for packaging, was the most common, followed by polyethylene, used in plastic bags, and then PVC.
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The particles can cause inflammation in tissue, as air pollution particles do, or the chemicals in the plastic can cause damage. In March, doctors warned of potentially life-threatening consequences after receiving a significantly increased risk of stroke, heart attack and earlier death in people whose blood vessels were contaminated with microscopic plastic.
Luigi Montano, from the University of Rome, who led the Italian study, said: “Intervention is needed to stop the exponential increase in plastic waste.” More than 180 nations are negotiating a UN treaty to regulate plastic and cut pollution.
“In particular, there is a need for action to avoid additional permanent damage to the planet and the human body,” Montano said. “If microplastic pollution affects the critical reproduction process, as is particularly evident from the decrease in seminal quality recorded worldwide in recent decades, it may turn out to be [even worse] for our species in the not too distant future.”
