How microplastics can impact health, as scientists discover them in human testicles

Microplastics are now inescapable - so much so that scientists have discovered their presence in human testicles.

A new study published in the journal Toxicological Sciences analysed tissue samples from 23 human testes and 47 canine testes. Microplastics were found in every sample, with researchers saying the discovery may be linked to a decline in sperm counts.

Professor Xiaozhang Yu, one of the study authors, told the Guardian he was initially sceptical that microplastics could penetrate the reproductive system.

He added that he was "surprised" by the results for both dog and human testes. As the tests in the study were taken from postmortems in 2016, Prof Yu warned that the "impact on the younger generation might be more concerning" due to the increasing volume of plastics in the environment.

The study comes after the UK government announced it will introduce a ban on wet wipes containing plastic from being sold in the country.

Steve Barclay, the Environment Secretary, announced the steps being taken to ban the supply and sale of wet wipes containing plastic. It comes after a survey showed an average of 20 wet wipes were found per 100 metres of beach across the UK.

Wet wipes also shed microplastics into the environment. Microplastics are defined by the UK Centre for Ecology and Hydrology as small particles of plastic with a diameter of less than 5mm.

In a statement, Barclay said: "Wet wipes containing plastic are polluting our waterways and causing microplastics to enter the environment.

"Defra (The Department for Environment, Food and Rural Affairs) will introduce legislation before the summer recess to crack down on this unnecessary source of pollution, following our successful single-use carrier bag charge and ban on microbeads in personal care products."

Scientists have begun examining the impact of microplastics on human health in recent years, and have made some alarming discoveries.

Where do microplastics come from?

Microplastics primarily come from the microfibres of clothing - and wet wipes - microbeads, and plastic pellets. They also enter the environment as tiny fragments from larger pieces of litter, like plastic bags, bottles or packaging.

They can measure between 5mm and one micrometre long - small enough to enter human cells.

Once in the waterways, soil, and general environment, microplastics contaminate everything - including living beings. A wide number of studies across the world have shown that animals are ingesting the polluting microplastics, including aquatic wildlife and wild birds.

A study by the UK Centre for Ecology and Hydrology found microplastic fibres in the gut of freshwater fish living in the River Thames, for example. Another study published in the journal Science of the Total Environment earlier this year also found microplastics in the digestive and respiratory systems of birds of prey.

In fact, every single bird tested in the study contained at least one microplastic in their digestive system. The presence of microplastics in the respiratory systems of 65% of birds tested also suggests that the animals are breathing in the pollutants.

There is evidence that microplastics have harmful effects on the animals that ingest or breathe them in. The pollutants stop them from feeding well, and can also impact their ability to grow, reproduce and defend themselves against predators.

How harmful are microplastics to humans?

Watch: Microplastics in blood linked with stroke, heart attack and early death, study finds

Since plastic plays a huge role in the everyday lives of humans, and it is known that microplastics can be ingested by humans through the food chain, studies are being carried out to determine the impact on human health.

A 2019 study by the American Chemical Society suggested that humans consume and inhale up to 211,000 microplastic particles every year.

The first study to link microplastics to health problems was published earlier this year. Scientists found that people who had microplastics in their blood vessels were more likely to suffer from cardiovascular disease.

Researchers in Naples, Italy, examined the build-up of plaque found in the arteries of 257 patients, who had undergone surgery to remove it. They discovered micro or nanoplastics in more than half of the samples.

It was also found that participants who had microplastics in their plaque sample were nearly five times more likely to experience a heart attack, stroke or death than those who did not have them.

A separate study also discovered the presence of microplastics in every single human placenta the researchers examined and tested, which raised concerns about the potential health impacts on babies growing in the womb.

Scientists analysed 62 placental tissue samples and found microplastics in all of them. The most common microplastic found was polyethylene, commonly used to make plastic bags and bottles.

Microplastics have also been found in human blood and breast milk. The World Health Organisation has called for more research to be conducted into the potential health impacts of the polluting substances.

Should I worry about microplastics?

Although microplastics are becoming increasingly prevalent, it is still unclear how much of an impact they have on our health, and whether we should be worried about whether they will make us sick.

Scientists are in the midst of studies and tests to see how the presence of microplastics in our bodies is affecting our health. It is yet to be determined how long they stay in the body and whether they have chemicals that will be detrimental.

However, there is ample evidence that microplastics are harmful to the environment and wildlife around us. They have been found in even remote corners of the planet, with scientists declaring that microplastic levels in Antarctica's remote Weddell Sea are even higher than previously thought.

Chemicals released from microplastics as they degrade can also affect the soil and water, passing on potentially harmful consequences to animals and organisms. The UN Environment Programme called for the "elimination of unnecessary plastic" and the "redesign of products" to help end plastic pollution.

The organisation said that redesigning products and packaging is crucial "so they can be more easily reused, repaired and recycled, and switching to non-plastic substitutes that help protect the environment, human health and our economy".

Read more about health and wellness:

• This Is The Reason Why People Living In Cities Are At Higher Risk Of Alzheimer’s Disease (HuffPost UK, 2-min read)

• Find Out How Plastic Waste and Water Pollution Affect Health (Yahoo News UK, 1-min read)

• How to reduce the amount of microplastics we consume (Yahoo News UK, 4-min read)