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Famed for their versatility, durability and cost-effectiveness, plastics changed the face of the industrial landscape in the early 1900s. Derived from crude oil fractions, plastics are polymers – long chains of repeating units – which can be moulded and shaped for a wide variety of applications ranging from clothing and packaging to aircraft and even spacecraft components.
There are many different types of plastic, but generally they can be grouped into two main polymer families: thermoplastics (which soften on heating and then harden again on cooling) and thermosets (which can only be moulded once, so must be stored in liquid form prior to manufacturing).
During the production of plastics, additional chemicals are often added, many of which are toxic. These additives have a multitude of functions, governing everything from colour and strength to antibacterial properties.
The very properties for which plastics are famed can also be considered their greatest flaw. Longevity, robustness and abundance has led to marine plastic pollution being dubbed “one of the most serious emerging threats to marine biodiversity,” according to the Convention on Biological Diversity.
The scale and quantity of plastic production is truly staggering – PlasticsEurope estimates that global plastic production now exceeds 280 million tonnes each year. The industry itself is worth over US$1 trillion according to experts.
To make matters worse, the emphasis on disposable goods means that only around a third of plastic products are recovered for reuse and recycling.
Much of the remaining plastic debris makes its way into the world’s seas and oceans, and is one of the most common components of marine litter.
Although marine plastic pollution is becoming more widely known by consumers, businesses and governments, much of the attention is currently focused on ‘macroplastics’ – larger pieces of over 5 mm in size.
Macroplastic pollution poses severe, well-publicised problems for marine fauna. Over 200 marine species are known to suffer from entanglement or ingestion, which can lead to choking and physical blockages, malnutrition, strandings and even death.
But perhaps a more sinister aspect of marine plastic pollution – and certainly one that is less well known and understood – is that of microplastics (particles measuring less than 5 mm).
First documented in the 1970s, the scale of microplastic pollution around the world has only recently received considerable press coverage following the discovery of the ‘Great Pacific Garbage Patch’ by Captain Charles Moore in 2000 and has been the focus of numerous scientific investigations.
So where do these microplastics come from? Well, some of it comes from the breakdown of larger pieces, however there are four notable direct sources:
One of the biggest problems with microplastic particles is that they are difficult to contain once they enter the marine environment because of their small size and ability to float.
Once they reach the sea, the surface of these microplastic particles often become colonised by micro-organisms, which alter the properties of the plastic, causing it to sink through the water column and become embedded in the seabed, shoreline, and plant matter. Clean-up operations thus become labour intensive, time consuming and costly.
When they reach the seabed, these plastic particles can obstruct the flow of oxygen through the sediment, causing anoxic conditions (the total depletion of oxygen) and the death of oxygen-dependent fauna and flora that live there.
Additionally, seabed filter feeders such as lugworms and mussels have been proven to consume microplastic particles, which can cause circulatory blockages. Not only is this harmful for the animals themselves, but there are also human health concerns about eating mussels contaminated with microplastics.
The effects of microplastic consumption are not just restricted to filter feeders either. Nurdles, in particular, resemble floating fish eggs and are regularly mistaken as a food source by a multitude of marine fauna. Seabirds are particularly affected. For example, it is estimated that 95% of northern fulmars contain microplastics in their stomachs.
In all cases, once consumed, these particles can lead to physical blockages, malnutrition, choking and even starvation. Several studies have shown some seabirds even regurgitate microplastics to their young during feeding.
The physical properties of plastic mean that – in the marine environment – microplastics are unlikely to ever fully degrade. Instead, they are broken down into smaller and smaller fragments, exacerbating the problem because they become more readily available to a greater number of species.
Plastics have also been proven to adsorb persistent, bioaccumulating and toxic chemicals (such as DDT), while toxic additives used during the production and manufacturing stages of plastic are likely to leach out over time.
Some of these toxic additives (together with toxins already present in the marine environment) are known to accumulate and magnify up the food chain. This has significant implications for global ecosystems, fisheries and – ultimately – human health.
At the very least, it raises questions about the labelling of ‘organic’ seafood products.
Fauna & Flora International (FFI) is developing a unique programme which aims to address the direct sources of microplastic pollution by working with businesses and stakeholders throughout the UK to stem the flow of microplastic pollution into the world’s oceans.
As part of this work, FFI will be launching the ‘Good Scrub Guide’ in the coming months. Through this innovative and novel project, will work with business leaders to stop the use of microplastics in personal care products such as facial exfoliators. Stay tuned for more news on this soon.
The very properties for which plastics are famed can also be considered their greatest flaw. Longevity, robustness and abundance has led to marine plastic pollution being dubbed “one of the most serious emerging threats to marine biodiversity.”
Project Officer, Marine Plastics