By Matt Smith
WebMD Health News
Plastic hasn’t been fantastic for the environment — and an eye-opening new report has raised concerns about what it may be doing to us. The report, produced by Orb Media in conjunction with researchers at the University of Minnesota and the State University of New York, found plastic in water almost everywhere. Tiny polymer fibers turned up in more than 80% of tap water samples collected worldwide, from rural villages in Uganda to New York’s Trump Tower.
That’s not a surprise to Stephanie Wright, who studies the spread of plastic waste worldwide. While the material has produced huge benefits, less than 10% of the 9 billion tons produced since the 1950s has been recycled; most of the rest of it is piling up in the trash or making its way toward the oceans, where it’s breaking up into ever-smaller pieces and being eaten by marine life or just floating around.
Wright, an environmental health scientist at King’s College in London, started off studying how plastics affect marine life and is now embarking on a study of how much of the stuff is in the air. While it’s not yet clear how that’s affecting us, Wright spoke with WebMD about how widespread the problem has become, what risks it may pose to your health and where those unknowns lie.
WebMD: How prevalent have plastics become in the environment?
Wright: They are considered ubiquitous, in at least a marine-science context. I think every study that has gone to look for plastics in the environment has found them. They’ve been reported in the poles, in Arctic sea ice, on deep ocean floor and all different oceans, surface environments and the water column. Basically everywhere we’ve gone to look for them, we’ve found them, which is quite unfortunate. That even includes remote Pacific islands miles and miles and miles away from any habitation …
We’re now starting to appreciate they’re in freshwater environments, including lakes, river systems and wastewater effluents. And recently we’ve started to recognize potential urban sources – things like tire-wear particles from cars, things like paint and coatings from buildings when they start to degrade, and clothing.
So the big picture that’s starting to form is this is a very widespread contaminant. And feeding into that are wastewater treatment facilities. They tend to capture a lot of these particles, but we predict that they’re actually caught up in the sludge, which is then applied to agriculture. So it’s very likely the soil is likely contaminated with microplastics as well.
WebMD: What are the biggest sources?
Wright: The main source we know of is just larger plastic items. If you think about global plastic production, most of that material is incorporated into packaging — everything that’s covered in plastic, essentially. That’s the issue. The packaging is simply used once and thrown away. It doesn’t always make it into landfills. It can get blown out of bins, or it can get lost in transport, or it can get blown out of a landfill, and that’s how it enters the environment.
In the ocean, 80% of the microplastics that contaminate it have stemmed from a land-based source. On the land-based sources, things like tires are a big contributor, and clothing or textiles. We most commonly find plastic fibers, which we believe stem from clothing, from washing-machine [wastewater] and general wear and tear on synthetic textiles.
WebMD: Which type poses the most risk of getting into living systems?
Wright: We’re not sure. In terms of what gets into animals and the environment, it’s a combination of fragments and fibers.
There’s a lot of studies that have been conducted looking at the capacity for certain animals to actually feed on these particles. But there’s not a lot of literature that’s sampled animals from the environment, and the handful that have done that have found a prevalence of fragments and fibers … fish, mussels, worms, have all been taken from the environment, and their stomach contents and tissue contents have all been shown to contain plastic fibers and fragments.
WebMD: What are the potential health concerns within human systems?
Wright: The first thing is the fact that they’re non-degradable. So if they are able to cross the lung lining or be engulfed by cells, that leads to bioaccumulation. With non-degradable particles, we know they cause inflammation, and chronic inflammation can lead to scarring of connective tissue and chronic injury of the localized area.
But the thing with plastics is …. they’re not just a non-degradable particle, they often have different chemicals associated with them. There are a range of additives which are incorporated during manufacture, but we also know there are a range of chemical pollutants that can attach to their surface if they’re in the environment.
The issue is, what dose are we being exposed to? What’s our level of exposure? Is it one particle that’s loaded with chemicals, but it goes straight through [the body], or is it just one particle in our lifetime? In comparison to other pollutants, how big a health threat is it? These are unknown questions.
WebMD: What route could they take to get into a human body?
Wright: It’s all a bit hypothetical at this stage, and based on the dietary sources that have been assessed so far. What you sample from the stomach of a fish isn’t necessarily what we would be exposed to, because we don’t ingest the stomach of a fish, and we don’t really know how small these particles are getting and whether they have the capacity to cross the gut of the fish and enter its circulation and distribute to the muscle we feed on. The worry comes from things like shellfish, where we eat the whole thing. So whatever’s in the shellfish at the point of eating goes into us, too.
There are studies which have shown shellfish purchased from the market are contaminated with microplastics, which you would then predict if you were to eat them, would go into you. We know things like sea salt are contaminated with microplastics, and honey and sugar … So we’re starting to piece together the different dietary sources. It’s by no means exhaustive, but considering diet, those are some of the routes of entry into our system. The flip side is what potentially could be airborne and what we could be exposed to via breathing.
WebMD: What are the big unknowns, and where should more research be concentrated?
Wright: We really are just at the beginning of our understanding. From a human health perspective, it’s important to focus on understanding what we are exposed to. That’s the abundance of microplastics in our immediate environment and our dietary sources — not just the number of particles and types of particles, but also what proportion of that is of a size that is biologically important.
That may mean it can cross the gut or the lung lining and interact with a cell and become localized somewhere. We really do need to understand our exposure and really push our understanding of the smaller particles … The questions are really, if you’ve got fibers in the drinking water of the size they report, what happens to that fiber in transit? Does it get stuck and lodged [in the body]? Does it get ingested by a cell, which I think is unlikely because of the large size of the fibers? Does it have any chemicals on it that could leach during transit?