Microplastics: how much do we consume and from which sources?
Microplastics is a growing concern for our planet. It is very widely found and has very diverse sources of pollution. How much do we consume and which items are the root cause?
Summary and TLDR
We eat and drink foods, which contain microplastics.
Bottled water appears especially high in microplastics compared to foods, doubling or tripling our microplastics consumption.
Main sources of microplastics are: decomposition of plastic packaging, washing of synthetic clothing and road tyre wear.
We need to at least reduce toxic additives.
This is part 2 of a 2 piece post. See the first one here on the overview on microplastic toxicity and the risk to human health.
We eat and drink microplastics
On average a person consumes 40-50k microplastics particles per annum. If bottled water is added, that can add up to 90k more microplastics particles per year and that is footnoted as an underestimation. Tap water is estimated to account for 10k particles per year (Raamsdonk paper).
Food and water
Few studies exist to review the full microplastics intake across our diet. Marine sources are most researched and consumption of shellfish and where we eat the whole gut of the fish are the cases of highest microplastics intake. That is so due to the tendency of microplastics to accumulate in the gut (Raamsdonk paper). There is research showing that sugar, salt, honey, alcohol, fruits all contain microplastics (source). Other foods probably contain it too, but there isn’t sufficient research yet.
Not skin contact
Good news on microplastics that apparently they cannot cross the skin - they can go deep into the skin but cannot cross the barrier into our inner bodies (Science News).
Where do microplastics come from?
Numbers vary quite a bit, but plastic packaging, synthetic clothing and tyres are considered the main contributors to microplastics.
Sources vary here somewhat, but this is my best understanding of the official research.
Breaking down of packaging and bags
I think over time we have been making more and more degradeable plastics. As a results when our plastic bags end up in landfill, they start decomposing. The faster they decompose, the more microplastics we get today. This is something to think about as there is a trend to make plastic with lower half-life - but that also drives up microplastic release rate.
Breakdown of old plastics is estimated to contribute 70-80% of total microplastics in the ocean (European Parliament).
Synthetic clothing
Synthetic clothing is estimated to contibute another 10% of microplastics in the ocean (European Parliament). Every wash of a synthetic fibre, such as polyester or nylon, leads to shedding of tiny particles into the water supply, which eventually ends up in oceans.
Tyres
Interestingly, tyre wear is a major contributor to microplastics in the ocean, roughly contributing another 10% of ocean microplastics (European Parliament). Some other studies cite even higher contribution - even that it might be the major source in certain cases.
While tyres are supposed to be rubber, a part of them are actually made of plastics to enhance performance. Tyres appear especially problematic as these tyre plastics includes heavy metals like copper, lead and zinc (Euronews). And if you recall from part 1 of the blog, heavy metals and toxic plastic additives are one of the major health risks associated with microplastics.
This calls for some thought as the transition to electric vehicles (EV) will lead to heavier vehicles on our roads further increasing tyre wear and tyre related microplastics.
Plastic and microplastics are part of our lives and bodies
In 80 years we went from nearly no man-made plastics in 50s to 400 million tons and more.
Source: Statista
The raw material which is used to make polymer plastic, crude oil, amounted to >4400 million tons in 2022 (Enerdata). That’s an interesting number - so around 9% of crude oil ends up as plastic.
The scale and growth of it is startling. We need to do better with recycling and most importantly, when looking at paths of damage, we should restrict toxic plastic additives such as phthalates, PFAS, heavy metals which then end up in human bodies causing health damage.
Before there is a 180 on plastic proliferation, we must adapt to survive with microplastics all around. One can hope that our bodies got that message already a few generations ago and have been constantly adapting over those 80 years as the plastics were coming in.