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Chemical pollution and microplastics: a present danger to marine life

Highly persistent harmful chemicals are found in marine animals all over the world. These chemicals are having lasting impacts on the health of wildlife, as even if they are banned they stick around. In addition, there’s now a new problem that is concerning scientists: microplastics from cosmetics and other applications  are polluting the environment, and helping to transfer harmful chemicals into marine food chains.

Old chemical pollutants that are still around

Polychlorinated Biphenyls (PCBs) are a group of chemicals that have been banned for over 30 years, but are still causing havoc. They were once used in electrical appliances such as transformers and TVs, but their highly persistent properties brought about a global ban. The persistence of PCBs means it is almost impossible for them to break down naturally in the environment. As such they are found all over the world in both on land and aquatic environments – in the body tissue of animals and humans. They accumulate in fat cells, and in oceans they found in higher quantities in animals near the top of the food chain. PCBs are endocrine disrupting chemicals (EDCs), that can upset the delicate hormone system, and they are known to suppress the immune system.


Harmful chemicals are effecting reproduction in UK Harbour Porpoises [Image: Erik Christensen via Wikimedia Commons]

In a study released this year, it was found that female UK harbour porpoises are having severe reproductive issues that may be caused by PCBs. In the study almost 20% of female porpoises showed reproductive failure, evidence of stillbirth, foetal death or recent miscarriage. A further 17% had infections or tumours of reproductive organs that could have contributed to breeding failure. UK harbor porpoises overall had lower pregnancy rates compared to populations of porpoises in areas with less PCB pollution.

In a press release for the study, Dr Sinéad Murphy, who led the study said:

Reproductive failure could have occurred in almost 40% of mature females sampled in this study. PCBs may have reduced foetal or newborn survival, something which has also been observed in other mammals. UK harbour porpoises are part of a larger north-east Atlantic population and our research suggests a population-level risk from PCB exposure.”

This is a widespread problem affecting numerous species. In the US, scientists studying the health of gulls in the Great Lakes have found that their eggs are contaminated with a host of different chemicals. These include PCBs and other chemicals including brominated flame retardants (BFRs), levels of which seem to be increasing (some BFRs have been banned, but not all). Some of these chemical contaminants mimic the female hormone oestrogen, and since baby birds are exposed to contaminants present in the egg, researchers said:

“The findings represent a “direct measure of exposure to developing bird embryos … It’s often the most sensitive life stage.”

Microplastics – a new threat to wildlife

Though PCBs have been banned, they and other chemical contaminants are still finding their way into aquatic ecosystems. A new study shows that microplastics can be a vector, transferring chemicals from the surrounding environment into marine food chains.

Microplastics are tiny pieces of plastic, smaller than 5mm that pollute the world’s oceans. They were first researched in 2004 when a team of scientists from Plymouth University showed that ‘microplastic particles had accumulated in the oceans since the 1960s and are now present worldwide. Even isolated environments are affected, with microplastics being ubiquitous in Arctic waters.

Microplastics originate in two main ways, firstly from products such as exfoliating beauty products, that have deliberately-added microplastic ‘microbeads’ that wash into the ocean via wastewater systems. Secondly, microplastics are also formed from the fragmentation of larger plastic items that have found their way into the ocean and have been broken down by sunlight. Research has also found that microplastics can be released when synthetic clothes (like fleeces) are washed.

Plastics like bisphenol A and chemicals such as phthalates, which are added to plastic during production, can have harmful hormone disrupting properties. But another key issue is that microplastics can also absorb harmful chemicals from the surrounding water or sediment. These chemicals can be persistent, bioaccumulative, and toxic substances, such as polychlorinated biphenyls (PCBs), polybrominated biphenyl ether (PBDE) flame retardants and dioxins.


Scientists used luminous plastic microbeads which can be seen under a microscope inside the zooplankton [image: Microplastic Ingestion by Zooplankton. Environ. Sci. Technol., 2013, 47 (12), pp 6646–6655]

A recent study has shown that tiny marine animals called zooplankton can mistake microbeads for food. The researchers found that the zooplankton each ate a number of microbeads, and the test showed that PBDEs from the plastic had transferred into the body tissue of the zooplankton (see photo). Zooplankton are near the bottom of the marine food chain and are eaten by a number of other species.  The test shows that microplastics create a risk of contaminating aquatic food chains, which in turn has the potential for increasing public exposure to harmful chemicals through seafood.

Another study has shown that fish that ingested plastic which had absorbed chemical pollutants from the environment suffered from liver toxicity, stress and disease.

Dr Michael Warhurst, Executive Director of CHEM Trust said:

“It is hard to understand why major companies started making and using polluting microbeads and other microplastics in their products.

It’s clear that microbeads should never have been used in everyday products, as companies must have known from the start that they would end up polluting rivers, lakes and oceans.

They must be banned as soon as possible, and efforts must be made to identify and control other sources of micro plastic pollution” 

Though microplastics are still used in many beauty products, there is beginning to be some – slow – regulatory action.

California has passed a law that will ban microbeads, though not until 2020. The Netherlands, Belgium, Austria and Sweden, with support from Luxemburg, have proposed a European ban on microplastics. Theses countries have called for the elimination of microplastics in products to be “of utmost priority.”

The Netherlands is particularly worried due to the ability of microplastics to contaminate their national production of mussels. Furthermore, Unilever, L’Oreal, Colgate-Palmolive, Johnson & Johnson and Procter & Gamble have all said that they will phase out the use of microplastics in their products.

What can you do?

  • Harmful chemicals accumulate in the oil and fat of marine animals, so though studies suggest oily fish is good for brain function and development, make sure not to consume too much; “NHS Live Well” gives details. Other tips on reducing your exposure to harmful chemicals can be found on our “Take Action as a Consumer” page.
  • Write to the politicians who represent you at UK and EU level. More information on how to do this can be found on our “Take Action as a Citizen” page.
  • The “Beat the Bead” campaign aims to phase out the use of microplastics in cosmetics. They have produced an app that you can use to find out which products contain microplastics, to help you make good choices when doing your shopping.