Chemical cocktail
Microscopic pieces of plastic are in our oceans, air, homes and, increasingly, us. They help to carry a “toxic sludge” of industrial pollutants into our bodies, and the chemicals used to make them have been associated with reproductive problems in men and
Microscopic pieces of plastic are in our oceans, air, homes and, increasingly, us. They help to carry a “toxic sludge” of industrial pollutants into our bodies, and the chemicals used to make them have been associated with reproductive problems in men and women.
Newborn babies seem so pure. Their miniature toes have never encountered the ground. Their g ummy mouths eagerly seek, for the first time, colostrum and then milk. But they have been connected to the outer world for months via the placenta that bonds them to their mothers. Today, that world is replete with minuscule pieces of plastic, and this year a scientific paper reported the discovery of microplastics in the placentas of four babies born in Rome. Just a fraction of a millimetre long, the particles were on the babies’ side of the placenta as well as the mothers’. The placenta is the interface between mother and baby that provides nutrients to the fetus and removes its waste.
The likely sources of the microplastics were revealed by their pigments: paints, adhesives, plasters, cosmetics and personal-care products. “Every time scientists have looked for microplastics in people, they’ve found them, including in faeces,” says Professor Sally Gaw, an environmental scientist at the University of Canterbury. “If they’re in the placenta, they will have come from the mother’s blood.”
The authors of the paper, titled Plasticenta: First evidence of microplastics in human placenta, suspect the particles entered the mothers’ bloodstream either through the lungs or intestines. They may have slipped between cells that line these organs or been engulfed by immune cells at the lining. In either case, another type of immune cell probably then consumed them and ejected them into the bloodstream.
“Very small particles – less than 10 to 20 microns – can cross from the lungs into the bloodstream. They can enter via the gut, too, and potentially trigger an immune response,” says Gaw. “In lungs, there is evidence of damage and inflammation. Their effect on human health is very much an emerging area and not a lot is known yet.
It’s hard to study. But we know that lungs don’t like tiny particles of any type, even cotton or smoke.”
EARLY DAYS
Most evidence so far on microplastics’ health effects comes from laboratory studies rather than real people. But the engulfing of tiny plastics by immune cells, the inflammation that happens when the body fights them, and the toxic loads they can carry – chemicals and microbes – are causing trepidation.
That trepidation extends to microplastics’ effect on ecosystems we rely on for food, water and air. Numerous studies reveal microplastics in every corner of the globe and every type of environment.
Ocean plastic continues to accumulate so fast that the Ellen MacArthur Foundation, which promotes the circular economy, estimates that at current rates, there will be more plastic than fish in the sea ( by weight) by 2050.
That’s easier to imagine in more populated areas of the planet, but New Zealand is not exempt: our coastlines, drinking water and food are not regularly tested for microplastics and they have been found in places that seemed sacrosanct.
Two scientists who focus on Aotearoa’s microplastics are Olga Pantos, a senior scientist with the Institute of Environmental Science and Research (ESR), and Grant Northcott, a consultant environmental chemist. I accompanied them to Kāwhia Hot Water Beach on the North Island’s west coast where they dug out sand to take back to the lab. It looked clean, but they’ll inevitably find plastic particles that were once bottles, lids, cups, tyres, fishing nets, ropes, food containers, toys and clothing.
These castoffs once fulfilled our wants and needs but have been broken down into microplastics by the elements. Because they’re 5mm or smaller, most are as invisible as a virus or a greenhouse gas. But specialised equipment can detect them,
Microplastics were found in the placentas of four babies.
and in the decade or so since people started looking, they have been found everywhere.
Pantos and Northcott co-lead a project funded by the Ministry of Business, Innovation & Employment (MBIE) to find out how much of the stuff is here and assess the risk microplastics present to our environment, economy and well-being. They’re joined by scientists from this country’s largest independent science organisation, the Cawthron Institute; crown research institutes ESR and Scion; and the universities of Canterbury and Auckland.
So far, the team have found microplastics in every beach, stream, sediment, estuary and ocean area they’ve sampled. They’ve found them flowing into the sea f rom wastewater treatment plants, sourced from factories, kitchens, laundries, bathrooms and digestive systems.
SEA CHANGE
Imagine a deep, calm bay in Queen Charlotte Sound/ Tōtaranui, next to a marine reserve. Here, in water about 50m deep, a team from the National Institute of Water and Atmospheric Research (Niwa) and the University of Auckland sampled the seabed. “There’s a perception that if it looks clean and clear, then it’s pristine, but you can’t see a lot of what’s going on,” says marine geophysicist Sally Watson, who co-led the pilot project.
“It was disappointing that we found microplastics not only on the seabed’s surface but also almost half a metre deep.” The team are seeking funding to look at longer sediment cores collected in the same area. They also found microplastics in the anchorage zone of Picton Harbour.
In Bay of Plenty estuaries, University of Waikato master of science student Anita Lewis found microplastics inside popular kaimoana, including wedge shells, which are similar to pipi, and cockles. She also tested tuatua from ocean beaches. The estuarine shellfish had the most microplastics, particularly the wedge shells, which, like pipi, feed on sediment. Cockles and tuatua, in
“This year, we published the first evidence of airborne microplastics in NZ.” Inhaled fibres are either trapped by our mucous membranes and swallowed, or travel into our lungs.
contrast, feed by filtering water, as do mussels. Microplastics show up in all of them.
The number of particles is small – less than one fragment per bivalve, on average. “New Zealand is better than other countries in terms of sediment microplastics,” says Lewis. “But it’s still a grim picture, not only for humans but also for other marine species, such as snapper, which eat shellfish.”
THE TINIEST BIG UNKNOWN
All scientists in this field are uneasily aware that there is more plastic around than they can detect. That’s because microplastic degrades into nanoplastic, which is measured at the infinitesimal scale of nanometres. “In New Zealand, we can’t measure nanoplastics,” says Gaw, who is part of the MBIE-funded research. “Some overseas groups have developed technology to do so. Plastic behaviour can change at that size and nanoplastics will be more easily transported into tissues.” Lab studies of human cells have found nanoplastics incorporated into proteins and accumulated inside cells. Detrimental effects such as oxidative stress were seen in some studies but not all.
Nanoplastics are causing problems at sea, says Pantos. “They’ve been seen to affect photosynthetic bacteria in the ocean, which is a huge problem because half the atmosphere’s oxygen comes from these bacteria.”
The air, too, has been invaded. “It’s said we each eat about a credit card’s worth of plastic every week,” says Northcott. “Goodness knows how much we’re inhaling.”
Laura Revell, an environmental physicist at the University of Canterbury, explains recent revelations. “In 2015, microplastics were found in the air above Paris. Then there were discoveries in other megacities. Two years ago, we received reports of them in the French Pyrenees, and then on fresh snowfall in the Arctic and Swiss Alps. It was literally snowing plastic.
“This year, we published the first evidence of airborne microplastics in New
Zealand, from above the University of Canterbury campus. It’s a sad reality.
“A study on the French Atlantic coast showed microplastics in onshore and offshore winds – it was blowing onshore from sea spray.”
Most airborne plastics, she says, are light fibres from synthetic textiles. The scientists interviewed by the Listener are concerned about synthetic clothing, particularly fleece, and synthetic textiles such as curtains, carpets and soft furnishings. Loosened fibres float outside and inside houses and in laboratories. Scientists have a strict fleece-wearing ban to avoid contaminating samples.
Synthetic fibres contaminate water, too, via washing machines. Estimates range from tens of thousands to millions of them escaping from a load of laundry. Most pass straight through wastewater treatment and enter the environment in effluent, as Helena Ruffell, a University of Canterbury master of science student supervised by Pantos and Gaw, has confirmed. Fibres can also emanate from clothes dryers and as we wear them. Airborne fibres land on our food and get eaten. Inhaled fibres are either trapped by our mucous membranes and swallowed, or travel into our lungs.
A BELLY-FULL
Microplastics were found inside popular kaimoana, including wedge shells, which are similar to pipi, and cockles.
Synthetic fibres contaminate water via washing machines. Estimates range from tens of thousands to millions of them escaping from a load of laundry.
It’s clear that microplastics are bad news for marine ecosystems. Pantos speaks of reproduction slow-down, diminished populations and behaviour changes. “Marine sediment worms have reduced body mass and hence fitness, which has a knock-on effect to their key role in maintaining sediment, so it has an ecosystem-level effect.”
In fish and the seabirds that eat them,