Microplastics in Water: How Concerned Should We Be?

Photo by Volodymyr Hryshchenko on Unsplash

2024 ended in a fairly crushing blow for the environment. And I’m not even talking about Trump. The UN’s global plastics treaty, officially the Intergovernmental Negotiating Committee (INC) on Plastic Pollution, met in Busan, South Korea, with expectations to become The Paris Agreement for plastics. Initiated in 2022 and promised to be finalised before the end of 2024, the treaty’s aims were to address the entire lifecycle of plastics — from production to disposal — with an internationally ratified policy agreed to reduce plastic production and waste, plus its knock-on impacts on the environment, human health, and water (we’ll get to that).

Leading the progressive charge was the Rwanda and Peru proposal: to cut the production of primary plastics across the world by 40% by 2040, from a 2025 baseline. That was on the table in Busan. NGOs believed that momentum was building to achieve it or something close, and The EU reaffirmed its commitment to ensuring production reduction by signing the Bridge to Busan declaration.

In the end, however, pessimists were not disappointed — the talks collapsed. Oil producing countries — principally Saudi Arabia, Russia and Kuwait — perhaps buoyed by the recent US election result, refused to play ball. “If we address plastic pollution, there should be no problem with producing plastics,” Abdulrahman Al Gwaiz, a Saudi delegate, told The New York Times. “The problem is pollution itself, not plastics.”

All the supposed ‘fifth and final’ treaty talks could agree on in the end was to meet again, for a sixth time at some unspecified point in 2025, kicking the plastic can down the road. Panama’s delegation head, Juan Carlos Monterrey Gomez told Al Jazeera, “Every day of delay is a day against humanity. Postponing negotiations does not postpone the crisis.”

But what has plastic pollution got to do with water? An awful lot, in fact. The plastic crisis plays a key role in the water crisis.

Quite why the exponential increase of plastic production is fundamental to modern water quality problem was made clear to me when I spoke with Nirere Sadrach, an environmental campaigner in Uganda, for my book The Last Drop.

“We are mapping the extent of plastic waste in the River Rwizi,” he shouted, gesturing behind him, where hundreds, if not thousands, of plastic bottles floated by on fast-moving water. “As you can see, our rivers are flowing with plastic, and there is not that much action from companies and our government…. We would like to see the companies producing these plastics take greater action to end plastic pollution now.”

Nirere began the #EndPlasticPollution campaign in 2019 to tackle what he saw as one of Uganda’s biggest environmental problems. Rivers flowing with plastic is a depressingly long-term problem. Nirere has recorded similar videos in many locations, including Lake Victoria, Africa’s biggest inland water body. The River Rwizi itself flows through ten districts and two large cities, as well as protected national parks and agricultural land: “important places for our country, for the ecosystem of our country . . . So, this plastic pollution problem is really devastating for us.” Nirere’s aim in founding End Plastic Pollution Uganda was to demand greater corporate responsibility from those generating the plastic — without a circular economy, the producers are the polluters. 

The effect on Lake Victoria, informed Nirere, is of “waters becoming a green plastic soup near the shores”, causing local water quality to become “really very, very poor . . . you can’t drink it, you can’t use it for anything”. His message is simple: “Companies should stop blaming people and consumers — it requires the company to change its product design or model.”

Wherever there is plastic in water, there are microplastics — typically defined as any plastic particle measuring less than 5 mm. Most of this comes as larger plastic debris in water degrades into smaller and smaller pieces. A significant amount also comes already in micro-form, from clothes-washing: a recent study found that machine-washing a single 6kg load of clothing can release more than 700,000 microfibres, most of which goes out into wastewater, and thus into our drinking reservoirs or out to sea.

Microplastics have since been found in every part of the globe, including both the North and South Poles.

If this seems abstract to your life and mine, however, then consider the following video taken under a microscope by Dr Richard Kirby from a random water sample off the UK coast near Plymouth. He found almost equal amounts of microplastic and zooplankton. Not just that, he recorded astonishing video evidence of microscopic plankton eating a single plastic fibre — perhaps one of the 700,000 microfibres from someone’s clothes’ wash— which it subsequently died from. This is the foundation of our food chain, vital to our very survival — and we are killing it.

“What intrigues me is that because the fibre has made a loop inside the animal’s gut, you can actually see the consequences”, Dr Kirby told the BBC, adding that the sight of plankton ingesting plastic was a relatively common sight in the samples he had collected from British waters. He hoped that the “genie was out of the bottle” now that his visual evidence of the impact of plastic waste in the marine environment. He was speaking in 2017. Things have gotten much worse since then. 

Source: https://www.statista.com/chart/32385/global-plastic-waste-production-by-application/

As well as eating it through bioaccumulation in our food chain, we are also directly drinking it. A global study of tap water found microplastics in 83 per cent of 500ml samples taken; the average number of microplastic particles found in each ranged from 4.8 in the US to 1.9 in Europe. When the study was repeated with bottled water — often sold as a ‘healthier’, more expensive ‘premium’ product — bottled water contained an average of 161.5 microplastic particles for every 500 ml, or 3,000–8,000 per cent more than ordinary tap water.

Plastic, as cleverer people than me will tell you, is an inert material — it isn’t toxic, albeit it can carry toxic inks and dyes on its surface. But in high enough quantities, inert or not, microplastics can clog up gills and digestive tracts in animals. And, of course, in humans. A 2021 Chinese study found that people with inflammatory bowel disease have 50 per cent more microplastics in their faeces. The most common type of plastic found in the stool samples was PET — the most widely and easily recycled plastic polymer used, among many other things, for bottled water.

Humans now ingest the equivalent of one credit card worth of plastic per week. Even before it’s thrown away, plastic food packaging has recently been found to contain at least 68 “forever chemicals” that can leach into our food. This should be concern us all.

I even spoke to a cattle farmer who only gave harvested rainwater captured from his shed roofs to his cows when they over-wintered in the sheds, never tap water. Why? One — it was a lot cheaper than paying the water bills. He calculated it saved him saved me £9,000 a year in water bills. which is reason enough. But reason two hit me harder: it was purer and produced better milk, being free of chlorine, microplastics, and all the other nasties than have since been found in our water supply. “I don’t think we should be feeding cows chlorinated water,” he said, with a firmness that made me wonder whether we should be feeding ourselves with it, either.

To be clear, we shouldn’t drink rainwater. Not only are there likely contamination risks from your roof and storage tank, but even if you somehow managed to keep both sterile, rainwater is too acidic to drink regularly and has none of the minerals we need from groundwater and surface water. That said, people in many countries do drink rainwater — and in modern rainwater harvesting systems, UV filtration and remineralisation can be added to make it safe. (Disclaimer: expert advice should be sought before trying this).

What has evolved to drink rainwater, however — and very much isn’t a fan of microplastics or chlorine, to name the two most obvious contaminants — are plants. Watering both your garden and indoor plants with harvested rainwater is far better for them. And, to a lesser extent, your pets. I often fill my dog’s water bowl up from my cleanest water butt. He’ll seek out the nearest puddle if I don’t, and only drinks tap water if he’s really desperate. 

Will rainwater from a water butt be entirely free of microplastics? Sadly, probably not. Your tank will almost certainly be plastic-based. The ‘leaching’ rate of the highest quality plastic is minimal, but there is some. Also, in 2023 a team of Japanese researchers became the first to detect airborne microplastics in clouds. By analysing cloud water collected from the summit of Mount Fuji, the team found nine different types of polymers and one type of rubber in the cloud particles. Their analysis suggested that the microplastics in the cloud originated primarily from the ocean — unsprisingly, given Dr Richard Kirby’s video above. Plastics are, then, not just part of our food chain — they are now part of our water cycle.

“Microplastics may have become an essential component of clouds, contaminating nearly everything we eat and drink via ‘plastic rainfall’”, said the co-author of the Japanese study, Hiroshi Okochi. 

We can reduce our exposure to microplastics in our immediate environment through measures such as rainwater harvesting and advanced filtration techniques. Both are important. Though when I asked a water quality researcher what water filter jug brand he’d recommend, he stately flatly “none of them”. They are, after all, plastic based. Personally, I now use a glass bottle with a simple binchotan active charcoal filter submerged in it (many big brand water filter jugs simply contain activated charcoal contained in plastic casing — so I’m simply cutting out the plastic middle-man).

But to eliminate plastics from our water altogether will take a concerted global effort. If that sounds impossible, then consider that we did it before by phasing out the similarly ubiquitous CFCs for the protection of the ozone layer thanks to signing The Montreal Protocol. We need the same now for plastics. Our water, and our health, depends on it.