Annastasia Kellett Wright: Microplastics and Manta Rays

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Annastasia Kellett Wright finds answers in the most unlikely places...

The ocean is home to a host of fascinating creatures, from colossal whale sharks to bioluminescent jellyfish. These aquatic beasts can teach us a lot about life on land, and invite us to ponder on their biological processes and habits. The manta ray is one such creature, which can grow up to an incredible 29 feet, and can live up to 50 years.

These elegant creatures are highly intelligent, with the largest brain of all fish species – studies have even demonstrated that they may be able to recognise themselves in a mirror. Unsurprisingly, manta rays are rated vulnerable on the IUCN Red List of Threatened Species.

Manta rays are filter feeders, able to sift zooplankton and krill through their mouths using rake-like fibres and expel seawater through their gill plates. However, the prevalence of microplastics in the ocean is proving devastating to them and other marine wildlife – these substances have been shown to block their digestive tracts and disturb digestive behaviour.

Microplastics are commonly around five millimetres in size, comparable to zooplankton which is a vital part of marine ecosystems and the main food source for planktivores such as the manta ray. Microplastics are known to cause digestive issues, potentially leading to dietary dilution, starvation and exposure to any toxic additives carried in the waste particles.

A separate yet interestingly related issue is that of a cocktail of raw sewage, microplastics and slurry that is coursing through all of England's rivers, putting health and nature at risk, as concluded by a recent parliamentary report. Agriculture and water companies are the biggest contributors to this "chemical cocktail", the Environmental Audit Committee warns.

Car tyre particles, oils and wet wipes are also clogging waterways, as are wastewater plants, which can create problems with waterway clogging causing reduced water flow and higher maintenance costs. They have been identified in sewage samples from a host of countries, including the UK.

To combat this problem researchers have begun studying the manta rays feeding process to ascertain how they are able to filter and separate plankton from seawater without clogging their gill plates. Although manta rays cannot actually filter microplastics, these researchers are hoping to use and develop a similar filtering concept in waste water management to prevent potential blockages and pollution.

Waste management and the ecosystem

It is estimated that in the UK alone, five million tonnes of plastic are used every year. By 2025, the ocean could contain one metric tonne of plastic for every three metric tonnes of fish, and many people are looking to greener, more sustainable alternatives.

Eco-conscious swaps might mean plumping for reusable water bottles or recycling and consuming products with less or recyclable packaging, all of which can contribute to the cause. Dentistry can also do its part in reducing waste and lowering its impact on the environment by making simple, eco-friendly swaps, while making patients more aware of greener ways to practice good oral hygiene.

From bamboo toothbrushes to recyclable paper cups, we should consider recommending alternative oral care products to patients, thus reducing dentistry’s overall impact on the ocean. Microplastics may still dominate ecosystems for years to come, but by employing eco-aware changes now, we could help keep the oceans fit for magnificent and valuable creatures like the manta ray for centuries to come.


Annastasia qualified as a dental hygienist and dental therapist from the University of Sheffield in 2013 and currently practices her full scope of practice with paediatric and adult patients in London. She has been a professional educator for Waterpik since 2016 and is actively involved with the British Society of Dental Hygiene and Therapists, acting as the trade liaison for their London regional group since 2015.

She adds: “With 300 million toothpaste tubes going to landfill every year, dentists could also recommend a more environmentally-conscious toothpaste. Arm & Hammer has formulated the UK’s first 100% recyclable toothpaste range, powered by baking soda.

“The range is clinically proven to improve gum health and remineralise tooth enamel, all the while containing no preservatives or artificial colours. The formula is vegan friendly and boasts of a completely recyclable carton, tube and cap.”

For more information about the Arm & Hammer toothpaste range, visit or email: This email address is being protected from spambots. You need JavaScript enabled to view it.