Micro Plastics and the threat they pose

What are the major causes?

A recent study found microplastics in 81 per cent of tap water samples globally. Such examples have, in the past few years, been discovered in mountain ranges in the likes of the US and France, with researchers even finding microplastics in rain. They have recently been found in the Arctic, too, giving an indication of their ubiquity. 

So where are these microplastics coming from? Without knowing the key sources, it is impossible to begin to understand how to tackle the problem. Here are the two key ways microplastics get into the environment.

• Runoff from land-based sources, such as agriculture, tyre wear on roads and landfills.

• Wastewater overflow, including treated water, as treatments cannot always capture such small particles. The microplastics come from the washing of clothes (microfibres), cosmetic microbeads, flushed period products etc. Every time we wash our clothes in the washing machine, millions of microfibres are shed. It is estimated that one load of clothes in a washing machine releases about 700,000 fibres per wash. Washing machine filters are not currently able to filter out these microfibres, so they work their way into our water systems.

What are the environmental impact of micro plastics?

Environmentalists will be no strangers to images of seabirds with plastics filling their stomach, but do microplastics cause the same harm? The science suggests that the environmental impacts can be severe and far-reaching, with microplastics being found in 47% of Fulmar guano samples (a good indicator of their presence in marine environments).

The potential issues are multifold. As plastics do not degrade, they accumulate both with ecosystems and up food chains. They can also absorb toxic chemicals and pathogens, providing another route of harm. Another issue is that for many organisms, ingested plastics can make them feel full, so they stop eating and eventually die of starvation.

Further to their effect on animals, microplastics have the potential to carry around pathogens and invasive species. High levels of microplastics on beaches may even change the temperature of the sand, affecting animals such as turtles where offspring sex is temperature-determined.

Despite the complex science (which there is a lot of), a 2017 United Nations resolution discussed microplastics and the need for regulations to reduce this hazard to our ecosystems. Such a measure was likely too little and too late to resolve the problem. It has become so widespread that it is almost impossible for it to not be seriously harmfil over the coming years which are only likely to add to the pressure on our oceans. 

Do they cause us harm?

There is a huge absence of science in this area, thanks in part due to the relative recency of interest in the subject, but also due to the difficulty of carrying out robust scientific studies on humans. It is estimated that the average person consumes up to 120,000 particles of microplastic each year, with that number increasing for those drinking mostly bottled water. However, whether or not this has had adverse effects in the decades we have been consuming them is not entirely clear.

As with many environmental issues, our exposure to microplastics is partially dependent on where we live. In the UK and other high-income countries, sewage treatments can effectively remove most microplastics from effluent, reducing the amount present in freshwater systems. In low and mid-income countries, however, only 33% of the population have sewer connections, meaning that for most of the population, water is poorly treated, leading to greater microplastic concentration in soils and water systems, and thus greater potential adverse health incomes.

For the most part in richer countries, drinking water is treated enough to prevent large quantities of microplastics working their way in. However, the smallest plastic particles can assimilate their way into our food, including seafood (primarily shellfish). While most plastics are inert (don’t readily react) and insoluble and therefore unlikely to be absorbed into our bodies, there are concerns about their absorption of toxic chemicals from the environment. However, with the relative paucity of scientific studies on the subject, there is not enough evidence to suggest a link between microplastics in drinking water and food and adverse health outcomes. This doesn’t mean that the link is not there, simply that more studies need to be done in this area.

What can we do?

We have thought of four simple swaps and ways to reduce micro plastics entering our environment:

• Reduce littering and improve collection systems

• Limit the introduction of new plastic sources into the environment. A lot of microplastic pollution comes from single-use plastics in one form or another, so by reducing the amount of plastic we consume, we can reduce the amount that eventually ends up in our ecosystems.

• Introduce global bans where possible on unnecessary use of microbeads (already done in the UK), for example in cosmetics, while recognising that this is only a small part of the issue.

• Improve plastic recycling systems and use them. Of the 8.3 billion metric tons of plastic that has been produced (2018), 6.3 billion metric tons has become plastic waste, and 91% of this has not been recycled. By reducing the amount of plastic sent to landfill we can reduce the amount of plastic breakdown there is globally. This includes dealing with our own plastic problem, and not shipping it elsewhere

Micro plastics are going to have a less visible but potentially more potent impact on our planet and we all are going to have to make changes to the way we shop and live.  So small changes to the products you buy will have a large impact. Rather than buy bottled shampoo (which leak micro plastics) use a shampoo bar.