You are probably familiar with the damage plastic waste is causing to the world’s oceans and environment. Over eleven million tonnes of plastic enter the oceans annually and these plastics break down into 170 trillion floating particles that are absorbed and eaten by marine life from the north to the south pole. What is less well-known is the emerging evidence that these microplastics have been found in human blood, tissue and even breast milk, having entered through the food chain, water and even plastic packaging and may be having a devastating impact human reproduction. In fact, there is growing evidence that microscopic plastic particles may be playing a part in the drastic reduction in male sperm count globally – a ticking reproductive timebomb that should concern us all.
Microplastic particles are pervasive environmental pollutants found in oceans, soil, air, and drinking water originating from broken-down plastic waste, synthetic textiles, and tire wear, and they persist in nature and accumulate in food chains, posing risks to biodiversity and human health. There are two categories of microplastics: primary and secondary. Primary microplastics are tiny particles designed for commercial use, such as cosmetics, as well as microfibers shed from clothing and other textiles, such as fishing nets. Secondary microplastics are particles that result from the breakdown of larger plastic items, such as water bottles. This breakdown is caused by exposure to environmental factors, mainly the sun’s radiation and ocean waves.
MICROPLASTICS HAVE BEEN DETECTED IN HUMAN SEMEN, TESTICLES AND PENILE TISSUE. THEY CAUSE ERECTILE DYSFUNCTION AND REDUCTION IN SPERM COUNT AND MOTILITY.
The problem with microplastics is that they do not readily break down into harmless molecules. Plastics can take hundreds or thousands of years to decompose and there is growing evidence linking them to impaired male reproductive health. We already have a huge dispersal problem. They are in the most remote places: the peaks of Everest, in the Mariana Trench in the ocean, in what we breathe and what we eat and what we drink. Microplastics, known as phthalates, can enter the human body through ingestion, inhalation, and even through skin absorption and, once internalized, can induce oxidative stress, inflammation, endocrine disruption, and cellular damage leading to impaired male reproductive health.
Microplastics have been detected in human semen, testes, and penile tissue. Studies suggest these particles contribute to reduced sperm count, decreased sperm motility, and erectile dysfunction, with higher, long-term exposure linked to testicular damage and reduced testosterone. Male sperm count in western countries between 1973 and 2011 declined by over 50% and recent studies suggest this decline is accelerating.
“At the beginning, I doubted whether microplastics could penetrate the reproductive system,” said Prof Xiaozhong Yu, at the University of New Mexico in the US. “When I first received the results I was surprised. The impact on the younger generation might be more concerning now that there is more plastic than ever in the environment,” Yu said.
The extent and potential danger of microplastics on the male reproductive system could fairly be said to represent a reproductive timebomb. Microplastics were detected in the testicles and semen of every single sample of a recent study and they have also been found in human follicular fluid where they can affect egg maturation. While other factors may come into play in the global decline in human fertility it is becoming clear that the avoidance of microplastics may be a significant factor in increasing fertility. The problem is not only with male of reproductive age either: Male babies can be affected in utero and early post-natal life with disruption of testicular development, low semen levels, low testosterone levels and decreased fertility in later life.
What can be done to resist these micro invaders? Some basic everyday measures may help: avoiding the heating of food in plastic containers, reducing consumption of plastic-bottled water, and choosing clothing made of natural fibres. Even a high-fibre diet has been shown to expel some microplastics through waste. What is really needed, though, is further scientific studies to fully understand the long-term impacts of microplastics on human reproduction. With global fertility already reduced from a global average of four children in 1950 to a projected 1.7 in 2100, and global population having peaked at 9.7 billion in 2064, the planet will very soon have fertility rates below replacement level, a problem that will affect everybody as the planet’s population ages with no sustainable replacement.
