Plastic debris, in all forms and sizes, is one of the most prominent threats to marine ecosystems worldwide, because large percentage of waste disposed at sea (60-80%) contains plastic. Only in 2012, approximately 165 million tons of plastic polluted the world’s oceans.
Macroplastics are a visible threat, but even more dangerous are the invisible microplastic fibers. Microplastics can be defined as pieces of plastic smaller than 5 mm.
Sources of microplastics:
The main source of microplastics is plastic disposed at sea, broken down into smaller particles due to chemical and natural processes. These tiny particles remain in the water, polluting our oceans for thousands of years. Other sources include:
- Factory products: Anything containing plastic can end up dissolving on a beach and pollute our seas with microplastics.
- Cosmetics: They may seem harmless, however products used for peeling, shampoos, deodorants, sun-screens etc. contain plastic microparticles that consist of polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polymethyl (PMMA) and nylon.
- Clothing made of synthetic fibers: It is estimated that a single piece of clothing made of synthetic fibers releases approximately 1,900 microplastic fibers tothe sewer system.
The average consumer disposes of 2,4 mg of microplastics daily. Although large volume of these ends up in wastewater treatment plants, their retention is not possible with the technology used today. Therefore, whether waste water is processed or not, all microplastics found in the products mentioned above go into the sea.
Small pieces of plastic or tiny fibers have been found in all marine organisms, including important commercial species of fish, mussels and crabs. Therefore, it is possible for the microplastics to enter the human food chain. Their number is expected to grow exponentially, given that until today the relevant research has been focused on a small percentage of aquatic species. Plastics contain toxic substances (flame retardants, antioxidants, softening agents etc.) and are able to absorb and accumulate other toxic substances found in seawater (like PCB and DDT). In areas of intense industrial activity these levels are much higher compared to other areas.
No matter where plastic is thrown away – in a forest, on a mountain, in a river, on a street etc. – it will pollute the environment. When plastic debris is in the form of large fragments, it is an obvious environmental threat, however when these fragments become invisible microplastic fibers, they are even more dangerous.
The spread of microplastics in marine ecosystems has only recently been discovered and constitutes a major threat to the environment and public health. Alarming is the fact that in many sea regions the concentration of plastic on transitional waters can surpass that of zooplankton by 6 times!
The myth of degradable plastic
In Greece, but also in many other countries, instead of adapting the good examples of many other countries that have established policies to control disposable plastic, we yet again preferred to remain regressive and simply decided to use the so-called “ecological” degradable plastics for bags, food packaging etc. However, their ecological feature is undermined by their ability to break up into pieces even faster than the usual plastics. They contain polyethylene, a chemical solvent with added pre-oxidants, which accelerates the disintegration and dispersion of plastics in the environment and the food chain, but doesn’t completely dissolve them. Therefore, this type of plastic is not a recyclable material.
How long does it really take to disintegrate plastic?
In recent decades there was a perception that hundreds of years are required for the breakdown of plastic waste. But modern research has proven that this is not true. For example, a plastic bottle on a beach is exposed to environmental conditions, such as ultraviolet radiation, wind, salt and sea waves, which accelerates the decomposition process and breaks it into small pieces.
Actions: Research and Its Results
Archipelagos Institute of Marine Conservation conducted its first survey to assess the extent of the distribution of microplastics in the Greek seas in 2009. The research illustrated the scale of the problem and the results were shocking:
- Analysing more than 1000 samples from 167 beaches of the Greek coast, there was no sample that did not contain fibers of microplastics.
- The beach sediments have the capacity to trap and accumulate tiny plastic fibers from the seawater. For this reason they are used as an indicator of the microplastic pollution level of a marine area.
- The microplastics are being dispersed by sea currents.
- Samples from beaches found in remote islands and uninhabited areas also contained microplastic fibers, in an amount equivalent to that of the beaches of Attica.
- Further analysis in 2012 and 2013 showed that almost 100% of fish and marine invertebrates (such as sponges and sea cucumbers) examined were also found to contain miniature fibers in their stomachs.
This confirms that microplastic particles are entering the food chain through our seas. It doesn’t mean, however, that we have to limit the consumption of seafood, but rather that we should be concerned for this massive source of pollution.
The goal of Archipelagos was to identify the main source of influx of microplastics into the Aegean and verify whether they are indeed traveling through the food chain, from plankton to humans.
Preliminary research in this area is still ongoing.