I am developing an artificial intelligence solution that detects floating plastic in the sea in freely available satellite images. As I am doing this in a voluntary capacity, if you have better financial means than I, then I encourage you to consider donating to the project. The below photo is also `for sale’ (available for licencing at a maximum resolution of 1000×1500 pixels). While I describe the technical side of the project over there on the fundraiser page, here the focus is on how we stand with plastic pollution.
Mar de plástico, the “sea of plastic” of greenhouses around El Ejido, Almería, Spain, highlighted using my developmental Ocean Plastic Detector algorithm.
Already several years ago, photos of decomposing birds whose stomach was full of plastic were doing the rounds on the internet. In September 2018, footage from the BBC documentary ‘Drowning in plastic’ showed how a chick was subjected to gastric lavage (stomach pumping) and how it threw up plastic debris. The explanation was that its parents had unwittingly fed it these plastic objects.
The Great Pacific Garbage Patch (GPGP) is an infamous mark that mankind has left on Earth. It is an over 1.5 million square kilometres large area of the Pacific Ocean (twice the size of Texas) that accumulates plastic debris due to the direction of ocean currents. Any trash that is not disposed of safely has a tendency to be carried by the wind or by rainwater runoff into streams, rivers, then into the seas and oceans.
But it is not only natural waters that transport plastic pollution. In a publication this April1, it was reported that in a remote location of the Pyrenees Mountains in southern France, it is `raining microplastics’. Scientist recorded a daily rate of 365 microplastic particles (249 fragments, 73 films and 44 fibres) per square metre falling from the sky. Their origin was determined to be up to 95 kilometres from where they were captured.
The lifecycle of plastic
How does it come to this? Plastic packaging is not inherently evil, I must stress. It is cheap and it keeps food hygienic and thereby prevents a lot of food waste. At the same time, it has been pointed out that it’s bizarre when we use a material with an extremely long lifetime for single-use products.
We manufacture about 400 million tons of plastic a year globally. Of this, packaging is responsible for about 38%. There is also plenty used in construction, to manufacture textile fibres for clothing, as material in consumer products, or in agriculture. For every human alive, there is about 50 kilograms of plastic produced every year, or almost 1 kilogram every week. But this includes the poorest people in the most impoverished countries, too. Some Western European countries produce 40-50 kilograms of rubbish per person in a year from plastic packaging only.2
Plastic does not break down by biodegradation. Its polymers break up to smaller and smaller pieces, helped by ultraviolet light, and large plastic objects turn slowly into small plastic debris and into a plastic dust. It still has the same mass but it’s more difficult to capture. This is the second law of thermodynamics at work: things have a tendency of mixing up and becoming less useful as a result. Macroplastic is any plastic object whose diameter is at least 5 millimetres. Plastic particles which are less than 5 millimetres long are called microplastics. Plastic bits smaller than 0.1 micrometres (100 nanometres) are called nanoplastics.
When you put plastic trash into the recycling bin, what does not happen you might expect to be happening is that it does not typically get shredded, melted down, whatever, and be used as raw material for the production of new plastic. Instead, the plastic actually puts on its reading glasses, and skims through some legislation which specifies what percentage of selectively collected waste must be recycled. As far as I remember, in Germany this is somewhere around half. The other half is incinerated (burnt) and is used to burn general waste, wet food waste so that they do not end up in landfill. The heat is used for power generation or to heat homes in the winter, but even then, about half the plastic you selectively collect has an unglamourous second life as a fossil fuel. That’s the end of it.
Not only birds but fish and shellfish (including mussels and oysters) also consume and accumulate plastic in their bodies. It is said that the larger a fish is, the longer it has to live to reach this size, and the higher the concentration of pollutants and toxins is that it accumulates. In this regard, small fish such as sardines and anchovies are less likely to contain high concentrations of pollutants.
It is also observed that plastic enters our bodies. A 2018 study of eight human stool samples from adults living in various European countries, Russia and Japan found on average 20 microplastic particles per 10 grams of stool. Polypropylene (PP) and polyethylene terephthalate (PET) were most frequently found in the samples. All study participants had consumed plastic-wrapped food or beverages from PET bottles.
A recent study made the bold claim that each of us might be ingesting 5 grams of plastic a week, or about the mass of a credit card. I am sceptical about this finding and the material unfortunately does not contain a detailed derivation.3
What is more trustworthy is that an average American consumes about 39,000 to 52,000 microplastic particles annually (and if you additionally consider inhalation, then the count increases to 74,000 to 121,000). The authors arrived at these numbers by retrieving from the scientific literature the measured microplastic content in different food ingredients that accounted for 15% of daily calorific intake, and by extrapolating from those numbers.4
There is plenty of uncertainty in the size (and mass) distribution of microplastics. Still, I could not see how this microplastic count (e.g. 1000 particles per week) could lead researchers to report as much as 5 grams intake per week.
Plastic particles are really everywhere. It’s easy to notice them once you start looking. My white plastic window frames, although they look new, turn the water white upon washing them. Sometimes I notice that they leave fine white dust on my fingertips when I touch them. This is from their outer side only, which has been exposed to strong sunlight for several years.
Most of the dust that accumulates in my home appears to be textile fibres. (Similarly, about 90% of the dust being deposited inside the Cologne Cathedral is textile fibres.) Its source must be the clothes I wear, the curtains, the bedclothes. How much of that is plastic is mainly a function of how much synthetic fibre content my textile purchases have. (Standard chemically treated cotton is not the most environmentally friendly material, either.) And there must be more plastic falling from the sky in a city than there is in the Pyrenees! Consequently, there is always enough dust in the air that whenever I shell a boiled egg, by the end its sticky surface captures dozens of fibre particles from my fingertips and from the air. From the looks of it, many of them must be synthetic.
How bad is plastic for you?
There is relatively little known about how much damage ingested or inhaled plastic causes to us. Microplastics are a new pollutant, like air pollution in cities from internal combustion engines. It is not clear that nanoplastic particles do not get into our cells if the particles are small enough, nor that they do not interfere with hormonal or intracellular processes. This is an active area of research and you should anticipate new findings in the press.
My personal view is that microplastic and nanoplastic particles seem to be pretty inert when you think about how rarely people get ill from this cause. Plastic does not cause acute poisoning — we would notice that. But its chemical properties suggest that it might be linked to or be responsible for a percentage of cancers, hormonal problems, infertility, and chronic inflammations of the digestive system.
The conclusion should be self-evident: use and contribute to the production of new plastics as little as you can. What plastic you have to dispose of, collect it selectively and make sure that it is handed over to professional waste management. Do your research, keep observing your behaviour and keep thinking how to cut down on new plastic input in your routine activities. If by hard thinking you find a way to eliminate plastic input in one recurrent activity, then its positive impact will add up over time.
Take your own shopping bags and possibly containers with you when you go shopping, and use them as long as you can so that you start using fresh ones later. Try to strike a good balance between sturdy but heavier plastic bags with more plastic content and short-lived but light plastic bags, and (preferably organic) textile tote bags. Tote bags are themselves no cure-all because of the water (and chemicals) input of (conventional) cotton growing, and because of their comparatively shorter lifespan. Try to buy clothes made of (organic) natural fibres and avoid synthetic fibres. Avoid buying cosmetics that contain plastic beads for rubbing your skin — waste water treatment does not capture microplastics and does not prevent them from entering natural waters. Try to steer clear of mixed-materials packaging such as plastic-coated paper drinks cartons or paper bags with a plastic window — materials that are hard to separate make recycling a Sisyphean task.
One large if not the largest source of fine plastic dust is actually tyre abrasion. This is one more reason to try to avoid travelling by car as much as possible. Most everything you can buy was transported at one point on a lorry or truck, which had tyres, and what you put in the bin will be transported on another one. So constraining your consumption generally has a small positive effect through this, too. Once a plastic item starts disintegrating, it is probably a good time to dispose of it safely, instead of letting it fall apart and scatter its debris. Cover your food and drinks if you leave them out in your flat to prevent dust from settling on them. Finally, be sensible and well informed. If one wants a soft drink, I would prefer a PET bottle to a can because the energy cost of producing an aluminium can is embarrassingly high.
1Steve Allen et al. Atmospheric transport and deposition of microplastics in a remote mountain catchment. Nature Geoscience, 12:339–344, 2019. doi: 10.1038/s41561-019-0335-5.
2Plastikatlas. Daten und Fakten über eine Welt voller Kunststoff (in German), June 2019. Heinrich Böll Foundation and Bund für Umwelt und Naturschutz Deutschland (BUND).
3Dalberg, an analysis for World Wide Fund For Nature. No plastic in nature: Assessing plastic ingestion from nature to people, 2019. (See especially ref. 15 therein.)
4Kieran D. Cox et al. Human consumption of microplastics. Environmental Science and Technology, 53(12):7068–7074, 2019. doi: 10.1021/acs.est.9b01517.