Highest levels of microplastics found in molluscs, new study says

Latest findings build on University’s research into plastics and the environment

Mussels, oysters and scallops have the highest levels of microplastic contamination among seafood, a new study reveals.

The research -- led by researchers at the University of Hull and Hull York Medical School -- looked at more than 50 studies between 2014 and 2020 to investigate the levels of microplastic contamination globally in fish and shellfish.

Scientists are still trying to understand the health implications for humans consuming fish and shellfish contaminated with these tiny particles of waste plastic, which finds its ways into waterways and oceans through waste mismanagement.

Study author, Evangelos Danopoulos, a postgraduate student at Hull York Medical School said: “No-one yet fully understands the full impact of microplastics on the human body, but early evidence from other studies suggest they do cause harm”.

Evangelos is one of three PhD students appointed as part of the Human Health and Emerging Environmental Contaminants research group at the University of Hull.

He said: “A critical step in understanding the full impact on human consumption is in first fully establishing what levels of microplastics humans are ingesting. We can start to do this by looking at how much seafood and fish is eaten and measuring the amount of MPs in these creatures.”

The study shows microplastic content was 0-10.5 microplastics per gram (MPs/g) in molluscs, 0.1-8.6 MPs/g in crustaceans, 0-2.9 MPs/g in fish.

The latest consumption data in the research shows China, Australia, Canada, Japan and the US are amongst the largest consumers of molluscs, followed by Europe and the UK.

Molluscs collected off the coasts of Asia were the most heavily contaminated, with researchers suggesting that these areas are more heavily polluted by plastic.

Evangelos said: “Microplastics have been found in various parts of organisms such as the intestines and the liver. Seafood species like oysters, mussels and scallops are consumed whole whereas in larger fish and mammals only parts are consumed. Therefore, understanding the microplastic contamination of specific body parts, and their consumption by humans, is key.”

Plastic waste generated worldwide is expected to triple to 155–265 million metric tonnes per year by 2060. Some of this plastic leaks into the environment and once the plastic finds its way into oceans, lakes and rivers it has the potential to end up as microplastic inside shellfish, fish and marine mammals.

The research also highlights the need to standardise methods of measuring microplastic contamination so that different measurements can be more readily compared. Researchers said more data is needed from different parts of the world to understand how these issues vary between different oceans, seas and waterways.

The paper, ‘Microplastic contamination of seafood intended for human consumption: a systematic review and meta-analysis' is published in Environmental Health Perspectives.

The publication of the study continues to build on the University of Hull’s reputation for plastics and other environmental research:


  • On world ocean day in 2018, a study of microplastics in mussels reported that 100 per cent of mussels sampled from around the UK coast contained microplastics or other debris. Scientists from the University of Hull and Brunel University, London collected samples from eight locations around the UK’s coastline as well as from eight unnamed supermarkets, representing eight different, unnamed brands. The study was published in the journal Environmental Pollution and attracted widespread coverage in the media.

    The same author team Professor Jeanette Rotchell, Dr Maureen Twiddy, Evangelos Danopoulos and Lauren Jenner recently published a systematic review and meta-analysis of studies of microplastics in drinking water and table salt as well as a study into the variable levels of microplastics in different seafood tissue parts. (This author team is part of the Human Health and Emerging Environmental Contaminants research group which also includes Dr Laura Sadofsky, Dr Andrew Boa, Dr Roger Sturmey, Dr Ireneous Soyiri, Dr Justin Sturge).

  • The Human Health and Emerging Environmental Contaminants research group, which brings together researchers from the University of Hull and Hull York Medical School, focuses on understanding the effect of contaminants on the human respiratory and reproductive systems, in addition to the gastrointestinal tract (as above). Respiratory work carried out by Lauren Jenner and led by Dr Laura Sadofsky has so far focussed on microplastics, having determined the level and characteristics of microplastics within the indoor, home environment. With this knowledge they hope to discover whether microplastics can be found within the human lungs and whether these particles have an adverse effect on respiratory health. Studies on reproductive systems, carried out by Vasiliki Papachristofi and led by Dr Roger Sturmey, are investigating the way in which newly emerging and established environmental contaminants affect the tissues of the female reproductive system in ways that change the periconceptual (around the time of conception) environment and the early stages of embryo development.

  • Previous research led by Dr Cath Waller at the University of Hull, along with colleagues at the British Antarctic Survey, showed how the levels of microplastic particles accumulating in the Southern Ocean, around Antarctica, are much worse than expected. Dr Waller leads the University’s Plastics in the Environment Research Group focussing on the environmental and social impact of plastics.

  • PhD Researcher, Freija Mendrik, recently published her research on the impacts of plastics on corals. The work exposed corals to different types of microplastic and measured photosynthetic yields, gross photosynthesis and net respiration. The work also tested whether impacts increased at higher temperatures that replicate ocean warming under climate change. Negative impacts were observed. However these effects were species-specific and the type of microplastics was found to be important with fibres (from clothes) causing the biggest (40%) drop in photosynthetic yield for the corals, which could reduce growth and survival.

Other environmental research

  • The University of Hull is recognised as a leading centre for research into environmental issues of global importance and interest. Researchers specialise in areas such as climate change, globalisation, renewable energy and low-carbon futures. Reducing the demand for single-use plastics and protecting our waters by reducing the impact of chemicals, plastics and synthetics are also key.

  • One of the University’s distinctive features is its strong research culture of collaboration and interdisciplinary working. Researchers across the University collaborate with University institutes such as the Energy and Environment Institute which has established a Plastics Collaboratory to bring together researchers across campus working on the critical issue of plastics in the environment and how to address this through evolving a new circular plastics economy.

  • The Energy and Environment Institute at the University of Hull brings together the skills and capabilities of leading researchers to tackle global challenges related to climate change and a low carbon transition, and their consequences for society and livelihoods. Home to over 100 staff and PhD researchers, the Institute is leading research in some of the areas of the world most at-risk from climate change, including flood prone areas such as Vietnam’s Mekong and Red River deltas, the Congo River in Africa, as well as locations much closer to home.

Other University partnerships focused on tackling some of the world’s greatest environmental challenges include:

  • Aura Innovation Centre, a University-led initiative, that works with SMEs and provides space for businesses to accelerate low-carbon projects, drive green innovation and deliver clean business growth. The Aura Centre for Doctoral Training, led by the Energy and Environment Institute, will appoint more than 70 PhD scholarships in offshore wind energy and the environment over the next 4 years.

  • THYME: The University of Hull’s Energy and Environment Institute is collaborating with partners at the University of York and Teesside University on a £5 million project to develop the bioeconomy across Yorkshire, the Humber region and the Tees Valley, building on the existing knowledge and innovation in the region. The University of Hull brings particular expertise in the bioeconomy, particularly on aspects of biofuels, renewable energy and the environment, as well as logistical aspects of the wider circular economy.

In November 2020, the University of Hull announced an ambitious eight-year plan to become carbon neutral by 2027, pledging a commitment towards a strong, sustainable future.

The University is introducing a range of measures, including a transition to renewable sources of energy to power the campus and reducing energy usage through optimising our estate and campus infrastructure.

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