The first evidence has been found that pregnant mammals are passing tiny plastic fragments to their offspring in the womb – raising fears that they may also be transferred from mother to foetus in humans.
Miniscule particles from disposable plastic bottles measuring less than a billionth of a metre across were absorbed, a study of pregnant and newborn rats found, by placentas and then passed by the mothers to the livers, kidneys, hearts, lungs and brains of their babies.
It was already known that plastic was being absorbed in the placentas of pregnant animals and humans, who absorb a credit card’s worth of plastic every day. But those studies didn’t determine whether mothers passed the plastics to their children in utero – which this latest research does.
The study, presented at the American Association for the Advancement of Science Conference in Washington, found that tiny ingested plastics, like those that permeate most food and water, “pass from pregnant rats to their unborn children and may impair fetal development”.
Professor Philip Demokritou, of Rutgers University in New Jersey, said the results of his study were “very alarming”.
“This is certainly cause for concern,” he said. “From the stomach of the pregnant animal, 24 hours later we found these micro- and nano-plastics in the placenta. More importantly, we found them in every organ of the foetus, which points to potential developmental effects.
“These findings demonstrate that ingested nanoscale polystyrene plastics can breach the intestinal barrier of pregnant mammals, the maternal-fetal barrier of the placenta and all fetal tissues.”
He added: “I don’t want to scare people but this is an emerging contaminant and we have a lot of unknowns in terms of the risks.
“Erosion chips microscopic particles off the billions of tons of plastics that are exposed to the elements in the environment. These particles mix with the food we eat and the air we breathe. A typical person ingests a credit card’s worth of them every week.”
Dr Demokritou added: “We cannot go back to the Stone Age, but as a society we need to become smarter, embrace sustainable concepts, to avoid crises like this.”
“Petroleum-based plastics are not biodegradable, but weathering and photooxidation break them tiny fragments. These tiny fragments, called micro-nano-plastics, are found in human lungs, placentas and blood, raising human health concerns. As public health researchers, we are trying to assess the health risks from such an emerging contaminant,” he said.
“It hasn’t been shown yet that the amounts of nanoscale plastics that pregnant humans unavoidably ingest do the same thing to their children, though some studies suggest plastics affect human embryonic development,” Professor Demokritou said.
Dr Luisa Campagnolo, an expert in embryology at the University of Rome Tor Vergata, who was not involved in the study, warned there was mounting evidence that micro and nano-plastics are ending up in human tissue.
“There are indications that most likely the foetus is a target for plastic particles. And so I would avoid stuffing the placenta with plastic particles, in order not to have the foetus affected,” she told the AAAS conference.
But she also pointed out that research into the impact of micro and nano-plastics on human health is in its very early stages and it is important not to jump to conclusions about the dangers.
The study is small – only looking at five pregnant rats and their offspring – while it is still unclear whether the findings apply to humans.
But researchers say it provides further concerning evidence that plastics are permeating all levels of the human and animal body and their offspring as well as every level of the food chain.
The full health implications of this are still little known but there is mounting evidence that they could potentially cause all sorts of problems, especially if consumed in large volumes. There are concerns that the tiny fragments could leach chemicals that have been linked to infertility, obesity, diabetes, prostate and breast cancer.
Other studies in pregnant laboratory animals have found adding plastics to food impairs their offspring in numerous ways, by restricting the growth of their offspring and harming the development of their brains, livers, testicles, immune systems and metabolisms during pregnancy.
Craig Bennett, chief executive of The Wildlife Trusts, said: “This study underlines my fear that we are witnessing just the very beginning of the plastic problem. Our seas, rivers and countryside are already plagued by plastic pollution.
“Research shows how humans and wildlife consume microplastics through eating, drinking and breathing. Despite all the public concern over this issue, the Government refuses to follow the precautionary principle and go for an outright ban on petroleum-based plastics.”
Nina Schrank, head of plastics for Greenpeace UK, added: “The sheer scale of plastic contamination is extremely alarming, it’s everywhere from the deepest oceans to the high Arctic, in our water, air, soil and food. And, of course, in our own bodies.
“The fact that nanoplastics seem to have little difficulty in crossing the natural barriers that should normally protect the blood, brain and developing young against contamination is yet another cause for concern.
“The level of waste plastic in the world’s natural systems is increasing rapidly, and yet the response from government has been a few token bans on specific products to get positive headlines, and almost no effort at all to determine what health impacts the microplastics infesting our world might have. This study highlights exactly why that work is urgently needed.”
Dr Campagnolo said there are simple steps we can all take to protect our health, she said. Plastic bottles can release debris, particularly when exposed to sunlight, which we then drink.
“It’s probably less handy but we should not drink bottled water in plastic bottles,” she said.
“We don’t have to freak out if we sit on a plastic chair, but I think we should avoid whatever is disposable, whatever is in contact with food, such as using plastic containers in the microwave oven. We should go back to glass. Disposable plastic took over probably 30-40 years ago but we can rethink this approach.”
The study, published in the journal Nanomaterials, provided specially marked nanoscale plastics to five pregnant rats. Subsequent imaging found that these plastic particles permeated not only their placentas but also the livers, kidneys, hearts, lungs and brains of their offspring.
Future research will investigate how different types of plastics cross cell barriers, how plastic particle size affects the process and how plastics harm fetal development, the researchers said.