An increasing number of studies have found that plastic particles are gradually spreading across the Earth, including in the sky, on the summit of Mount Everest, in the depths of the Pacific Mariana Trench, and even inside the human body. These plastic particles not only harm the environment but also have strong adverse effects on human health.
Plastic particles with a length or diameter smaller than 5 millimeters (mm) and nanoscale plastics are collectively known as “microplastics.” These microplastics have contaminated archaeological sites, clouds in the sky, seawater, and even human drinking water and food, ultimately entering and accumulating in the human body.
Plastic microplastics mainly come from visible plastic products in daily life, including skincare products, electronic products, and synthetic fibers in clothing. Many research reports indicate that plastic microplastics not only adsorb toxic heavy metals or release harmful chemicals, but also severely impact human health. Microplastics smaller than 100 nanometers (nm) can almost reach all human organs.
A research report published in the journal “Toxicological Sciences” on May 15 of this year has attracted the attention of over 300 media outlets and social media platforms. The research, led by scientists from the University of New Mexico, studied the reproductive aspects of 23 male humans and 47 male dogs, discovering an astonishing presence of 12 types of plastic particles in their testicles.
The age of the 23 men ranged from 16 to 88 years, and the samples collected have been preserved since 2016. Researchers found that the content of plastic particles in the testicles of human males increases with age, indicating an accumulation of plastic particles over time.
According to their calculations, the average total plastic particle content in dogs was 122.63 µg/g, while in humans, it was 328.44 µg/g. This shows that the total microplastic content in human testicles is nearly three times higher than in dog tissues. Human testicles contained high concentrations of plastic particles such as PE, PVC, ABS, PC, among others.
Researchers believe that the difference in plastic particle concentrations between humans and dogs may be related to factors such as lifestyle, diet, and living environment, as humans are exposed to a greater variety and quantity of plastic items compared to dogs.
The detection of plastic particles in the human body is significantly higher than a study on human blood samples conducted in November 2023, where the concentration of plastic particles in human blood was only a few tens of micrograms per milliliter (µg/ml), leaving the researchers shocked.
A study in South Korea in May 2023 pointed out that plastic particles can affect various human systems such as digestion, respiration, endocrine, reproduction, and immune (abnormal inflammation) systems, also disrupting hormone production, release, and metabolism in the body.
Additionally, the incidence of Testicular Dysgenesis Syndrome (TDS) in modern men is on the rise. This condition can lead to conditions like hypospadias, cryptorchidism, and testicular germ cell cancer. TDS has been linked to phthalates, pesticides, heavy metals, classified as endocrine-disrupting pollutants (EDCs).
Scientist previously conducted small-scale studies on five human testicles and 30 sperm samples, discovering plastic particles and raising concerns about their potential accumulation in the male reproductive system. Animal studies suggest that plastic particles can reduce sperm count in testicles and cause hormonal imbalances and abnormalities.
A study summarized in the “Human Reproduction Update” magazine in November 2022 analyzed male data from 53 countries, revealing a 51.6% drop in global average sperm count between 1973 and 2018, presenting a concerning trend for human reproduction.
A 2022 study showed that human blood samples contained plastic particles at a concentration of 1.6 µg per milliliter, with the highest concentration recorded at 12 µg. In human placenta (with fetus), plastic particle levels ranged from 6.5 to 790 µg/g at 8 months, with an average of 126.8 µg/g.
The University of New Mexico’s research identified polyethylene (PE) as the primary plastic residue in the testicles of humans and dogs, which is one of the most commonly used plastics by humans. Additionally, specific plastic polymers such as polyvinyl chloride (PVC) and polyethylene terephthalate (PET) were observed in the testicles.
Despite progress in understanding the effects of plastic particles on the human body, there is still a need for extensive research to determine the concentration of plastic particles in the human body and at what levels they affect reproductive health. Researchers state that further studies are required to provide clear evidence of the direct impact of plastic particles on sperm quantity and quality.
Inspired by the alarming levels of plastic particles found in human placenta, Professor Matthew Campen, from the university’s College of Pharmacy initiated the research project in collaboration with Dr. John Yu. They believe these substances are affecting reproductive capabilities and are conducting in-depth investigations.
Lead author John Yu mentioned to the British newspaper “The Telegraph,” “Initially, I was skeptical about whether plastic particles could penetrate the reproductive system. However, when I received the test results for dogs, I was surprised, and when I received the results for humans, I was even more surprised.”
He explained, “The presence of PVC plastics is particularly concerning because it releases many chemicals that disrupt endocrine systems, affecting sperm production in testicles.”
Dr. Saurabh Sethi, a gastroenterologist from California, has issued warnings about plastic bottled water. He pointed out, “The average plastic bottled water sold in the US contains around 240,000 plastic particles per bottle, which can accumulate in the body and have high correlations with cancer and infertility. It is advisable to avoid using plastic bottled water.”
He also mentioned that drinking water from plastic bottles in hot weather is the most harmful, as heat can release more plastic particles into the bottle. Chemical experts suggest drinking filtered tap water and using cups made of alternative materials, as tap water contains far fewer plastic particles compared to bottled water.
Perch Energy website provides suggestions to reduce plastic particle intake or exposure, such as choosing clothing made of natural fibers like pure cotton, silk, wool, and hemp to decrease the use of synthetic fiber clothing. Also, reducing water and detergent usage during laundry can help minimize the generation of plastic particles. Additionally, air-drying clothes instead of using a dryer, minimizing the purchase of new clothes, or using non-plastic cosmetics can reduce plastic particle intake and generation.
They also recommend reducing the consumption of shellfish, mollusks, shrimp, lobsters, crabs, and oysters as these bottom-dwelling species are more likely to ingest ocean-sourced plastic particles. Furthermore, they advise against heating plastic food in the microwave, even if the plastic container is labeled as “microwave safe,” as heating can release toxic substances from the plastic.
Finally, they suggest regular dusting and vacuuming on a weekly basis to reduce the inhalation of more plastic particles, as around 39% of household dust particles consist of these substances. It is also recommended to avoid using plastic carpets on the floor to effectively minimize the inhalation of large amounts of plastic particles.