Microplastics: scientific evidence

Today, a significant number of personal care products such as scrubs and toothpastes are known to contain thousands of minuscule balls of plastic called microplastics, or more specifically, microbeads. Over the years, microbeads have replaced traditional, biodegradable alternatives such as ground nut shells, and salt crystals.

The microbeads used in personal care products are mainly made of polyethylene (PE), but can be also be made of polypropylene (PP), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA) and nylon. Where products are washed down the drain after use, microbeads flow through sewer systems around the world before making their way into rivers and canals and ultimately, straight into the seas and oceans, where they contribute to the plastic soup. Typically, microplastics are defined as: plastic pieces or fibres measuring less than 5 mm. The microbeads found in personal care products are almost always smaller than 1 mm.

In 2004, the findings of a research programme led by Professor Richard Thompson (University of Plymouth) were published in Science and detailed the distribution of microplastic pollution. The article was the first to conclude the spread of microplastics and plastic fibres throughout the entire marine environment. And since larger pieces of plastic break down into smaller pieces and do not biodegrade, the amount of microplastics is accumulating.I Plastic degrades into ever smaller pieces upon exposure to UV radiation and as a result of abrasive wave action.II The concentration of marine microplastics is accumulating rapidly.III

In addition to these indirect, secondary sources of microplastics, there are several direct sources of microplastics – including the flushing of microbeads used in personal care products. Hundreds, if not thousands, of different personal care products use microbeads as abrasive scrubbers and for cleansing purposes. In 2009, Fendall and Sewell (University of Auckland) published their observations that microbeads pass into household waste water streams directly and are too small to be retained by the standard filters used at sewage treatment plants and therefore enter the marine environment. Not only do they enter the sea, they can also enter the food chain.IV

Although the full extent and consequences is hard to quantify, the accumulation of plastic, including microplastics, in the marine environment is today recognised as a serious, global environmental issue.V As scientists and policymakers alike start to question the full extent of the problem in terms of impacts to marine biodiversity and associated implications for human health, the number of research programs studying microplastics is increasing consequentially.

If you are interested in more scientific findings and articles, check out the list below:


➢ In UNEP Frontiers 2016 report, Emerging Issues of Environmental Concern, provides an accurate summary on the issue of microplastics under the heading "Trouble in the Food Chain".

➢ The intake of microplastics by oysters cause feeding modifications and reproductive disruption with significant impacts of offspring. See: Rossana Sussarellu, ‘Oyster reproduction is affected by exposure to polystyrene microplastics,’ 2430–2435, in: PNAS, vol. 113 no. 9.

➢ The population of European Perch is being threatened by microplastics pollution. Microplastics alter feeding preferences and hatchlings prefer microplastics above natural food. It makes young perch less adtive and an easy prey for predators. See: Lönnstedt O.M., Eklöv P. 2016, ‘Environmentally relevant concentrations of microplastic particles influence larval fish ecology,’ in: Science (doi: 10.1126/science.aad8828).

➢ Microplastics in leave-on products like make-up are much smaller than microbeads in scrubs. In sunscreen particles of 0.0003 mm are(w hich means 10-100 trillion particles in one single sunscreen). Read the report by Eunomia commissioned by the European Commission.

➢ Plastic debris has become a human health issue. Humans ar being exposed to plastic particles and a complex cocktail of contaminants. Read the article by prof. Vethaak and Leslie in  Environmental Science & Technology.


➢ 5000 to 95,000 microbeads are released into the environment with every single use of personal care products. This has been researched by various scientists and published in the Marine Pollution Bulletin.

➢ Tackling plastic pollution at its source is the most effective way to reduce marine litter according to the Institute for European Environmental Policy.

➢ Microbeads which are harmful to human health accumulate in all kinds of fish and shellfish such as mussels, tuna, oysters, salmon and anchovies. This has been confirmed by scientific research.

➢ United Nations experts state that what is known as the 'circular economy' (based on recycling) is the best and cheapest way to reduce the amount of microplastics ending up in the oceans.

➢ Scientists have discovered that mussels which are exposed to high concentrations of plastic display signs of stress. More research is needed to discover the full effect of plastic in sea creatures.

➢ Microbeads are found in plankton and this is probably how they enter our food chain. Watch the video on:

➢ Recent studies have shown microplastics can be found on almost every beach worldwide, on polar icecaps and just about everywhere in the oceans.

➢ Substantial quantities of microplastics in the ocean sink to the bottom. This is shown in a recent study into plastics in the Atlantic Ocean, the Indian Ocean and the Mediterranean Sea. A team of scientists researched these oceans between 2001 and 2012 to a depth of up to 3000 metres. The amount of plastic on the ocean floor is 1000 times greater than the amount floating on the surface.

➢ The ocean contains an estimated minimum of 5.25 trillion plastic particles weighing nearly 296,000 tons of floating particles.

➢Microplastics in toothpaste are 100 times smaller than in scrubs. The National Institute for Public Health and the Environment states that the lower limit for the size of plastics should be 1 µm.

➢ According to the UNEP, microplastics are the most harmful pollutants currently chocking the oceans.

➢ Microbeads - A Science Summary.


Marine species are unable to distinguish between food and microplastics and therefore indiscriminately feed on microplastics. In an overview published for the Convention on Biological Diversity, it was shown that over 663 different species were negatively impacted by marine debris with approximately 11% of reported cases specifically related to the ingestion of microplastics.VI Some species of fish excrete plastic easily, but others do not and so accumulate plastic internally. To cite one study: around 35% of 670 fish examined (total of 6 species) had microplastics in their stomachs. The highest number of fragments found in one fish was 83.VII

The surface of microplastics has been proven to attract and absorb persistent organic pollutants (POPs) such as PCBs and DDT from the marine environment. Relatively high concentrations of POPs have been found on the surface of microplastics.VIII The International Pellet Watch, led by Professor Takada at the University of Tokyo, is conducting research to this effect. Takada’s research indicates that certain POPs found in bird tissue were ingested together with their plastic hosts.IX In theory, ingested POPs could remain on the surface of ingested microplastics and could be egested.X However, fish and seafood regularly consumed by humans have been recorded with plastic fragments inside their guts and body tissues. Scientists hypothesise that over time, POPs will start accumulating in the food chain, transferring from species to species, with consequences ultimately for humans.XI

Toxic chemicals added to plastic during the manufacturing process (such as plasticisers and flame retardants) leach out of plastic in the marine environment and pose serious threats to marine fauna.XII The most common plasticisers have been recorded in fish, marine mammals and molluscs.XIII The smallest particles of plastic are ingested and retained by filter feeders such as mussels. Belgian toxicologist Colin Janssen (University of Ghent) found that on average, each gram of mussel flesh contains one particle of plastic.XIV Species of plankton are also found to ingest and retain plastic particles.XV

Once microbeads reach the marine environment, it is impossible to pinpoint the source of origin. German researchers Liebezeit and Dubaish (University of Oldenburg) hypothesise that cosmetics, and especially peelings, make up most of the microplastics they found in the Wadden Sea.XVI

In terms of relative contributions to microplastic pollution, a range of studies have looked at the number or concentration of microbeads in individual products. The American non-governmental organisation (NGO) 5Gyres, found a large number of microplastics in the Great Lakes and estimates that one single care product (Neutrogena's Deep Clean) contains 360,000 microbeads.XVII Dr. Leslie (VU University, Amsterdam) found that microplastics made up 10.6% of one scrub (Exofonic scrub of L'Oreal).XVIII

Water treatment plants are not designed to filter out microbeads. A number of studies have found that water treatment plants do not filter all microbeads from the waste water.XIX Moreover, not all waste water gets purified. Following heavy rain, waste water with microbeads can overflow directly into surface waters. Some countries lack the infrastructure to treat waste water completely.

As scientific understanding of the effects of microplastics on the environment continues to grow, the fate of microplastics has become an extremely important question. Increasingly, sources and impacts of microplastic pollution are being questioned and considered closely by scientists and policymakers alike. For instance, within the framework of the CleanSea European research project, seventeen European research institutes are conducting interdisciplinary investigations into the effects of microplastics.

Research into the quantity and consequences of microplastics in the environment is important. In light of growing evidence confirming the seriousness of this issue, there is a pressing need to address direct sources of microplastic pollution – something that is both unavoidable and highly necessary.

Producers have been asked to act responsibly and stop adding microplastics to cosmetics.

Dr. Heather Leslie of the Institute of Environmental Studies (Free University, Amsterdam) publishes a Review of Microplastics in Cosmetics. Scientific background on a potential source of plastic particulate marine litter to support decision-making.

2013, fourth quarter

Dr. M. Eriksen et al. publishes a scientific paper 'Microplastic pollution in the surface waters of the laurentian Great Lakes', in: Marine Pollution Bulletin 77 (December 2013). 



R.C. Thompson, et al. ‘Lost at Sea: Where Is All the Plastic?’, in: Science, 304 (May 2004).

II P.K. Roy, et al., ‘Degradable Polyethylene: Fantasy or Reality’, in: Environmental Science and Technology, 2011, pp. 4217–4227.

III M.C. Goldstein et al., ‘Increased oceanic microplastic debris enhances oviposition in an endemic pelagic insect’, in: Biology Letters published on line 9 May 2012; C.J. Moore, ‘Synthetic polymers in the marine environment: A rapidly increasing, long-term threat’, in: Environmental Research108 (2008), pp. 131-139.

IV L.S. Fendall, M.A. Sewell, ‘Contributing to marine pollution by washing your face: microplastics in facial cleansers’, in: Marine Pollution Bulletin, 58 (8) (2009), pp. 1225-1228.

W.J. Sutherland et al., ‘A horizontal scan of global conservation issues for 2010’, in: Trends in Ecology and Evolution, 25, pp. 1-7.

VI Secretariat of the Convention on Biological Diversity and the Scientific and Technical Advisory Panel—GEF (2012). Impacts of Marine Debris on Biodiversity: Current Status and Potential Solutions, Montreal, Technical Series No. 67.

VII Chr.M. Boerger et al., ‘Plastic ingestion by planktivorous fishes in the North Pacific Central Gyre’, in: Marine Pollution Bulletin 60 (2010), pp. 2275-2278.

VIII Y. Mato et al., ‘Plastic Resin Pellets as a Transport Medium of Toxic Chemicals in the Marine Environment’, in: Environmental Science & Technology, 2001, 35(2), pp.318-324.

H. Takada, et al., ‘Accumulation of plastic-derived chemicals in tissues of seabirds ingesting marine plastics’ in: Marine Pollution Bulletin69 (2013), pp 219-222.

E.M. Foekema et al., ‘Plastic in North Sea fish’, in: Environmental Science & Technology, 47 (2013), pp. 8818-8824.

XI P. Farrel en K. Nelson, ‘Trophic level transfer of microplastic: Mytilus edulis (L.) to Carcinus maenas (L.)’, in: Environmental Pollution 177 (2013), pp. 1-3.

XII D. Lithner et al., ‘Environmental and health hazard ranking and assessment of plastic polymers based on chemical composition’, in: Science of the total environment 409 (2011), pp. 3309–3324.

XIII STAP. Marine Debris as a Global Environmental Problem: Introducing a solutions based framework focused on plastic. In A STAP Information Document, p. 40. Washington, DC: Global Environment Facility, 2011.

XIV L. Van Cauwenberghe, ‘Occurrence of microplastics in mussels (Mytilus edulis) and lugworms (Arenicola marina) collected along the French-Belgian-Dutch coast, in: J. Mees, et al. (ed.), Book of abstracts - VLIZ Young Marine Scientists' Day. Brugge, Belgium, 24 February 2012. VLIZ Special Publication, 55.

XV Cole M., et al., ‘Micro-plastic ingestion by zooplankton’, in: Environmental Science & Technology, 2013 47 (12), pp. 6646-6655.

XVI G. Liebezeit, F. Dubaish, ‘Microplastics in Beaches of the East Frisian Islands Spiegeroog and Kacheloplate’, in: Bulletin environmental contamination and toxicology, 89 (2012), p. 213-127.


XVIII Leslie, H.A., Microplastic in Noordzee zwevend stof en cosmetica. Eindrapportage W-12/01, IVM Institute for Environmental Studies, Amsterdam, 2012.

XIXM.A. Browne et al., ‘Accumulations of microplastic on shorelines worldwide: sources and sinks’, in: Environmental Science &Technology 45 (2011), pp. 9175/9179; H.A. Leslie et al., ‘Verkennende studie naar lozing van microplastics door rwzi’s’ in: H2O 14/15 (juli 2012), pp. 45-47.