PKG0030

 

Written evidence submitted by Dr David Morritt, Head of School of Biological Sciences, Royal Holloway University of London

  1. This response primarily addresses the impact and potential impacts of the questions referred to in the terms of reference of the inquiry. This is based on research carried out and ongoing in the School of Biological Sciences (SBS) at Royal Holloway. 
  2. We are conducting a programme of research in relation to plastic pollution in the Thames, which was the first study to identify the scale of movement of plastic pollution below the surface of the river (“sub-surface debris”) in the River Thames and then identify the issue of plastic ingestion by Thames estuary fish.
  3. The majority of this work has been carried out in collaboration with colleagues at the Natural History Museum (NHM) so this response should be read alongside the fuller submission from the NHM. For sake of brevity I will therefore limit this submission to a few key points.
  4. Our research has focused on the description of sub-surface plastic debris which is assumed to be moving along the river bed and, in the process, being fragmented to produce smaller particles which are then more available for ingestion by aquatic animals. This debris included plastic cups and other plastic food packaging. Our work has shown that fish do indeed ingest plastic fibres and fragments. Latterly our research has also focussed on floating plastic waste, specifically plastic beverage bottles, which typically accumulate on shorelines where they potentially impact different species in the Thames environment.
  5. More specifically:

5.1.   Fyke net1 fishing trials led by Dr Dave Morritt (Royal Holloway) and Dr Paul Clark (NHM) identified 8, 490 items of largely plastic debris during a three month period. Approx. 30% of these items, assumed to be moving along the river bed were plastic cups, cutlery and other food packaging. Perhaps 5% of the items were plastic cups and less than 1% plastic beverage bottles. The low value of the latter is because these items typically contribute to floating debris (see below). This research was published in Morritt et al. (2014).

5.2.   Subsequent work at Royal Holloway (in collaboration with NHM) looked at gut contents of selected Thames fish and showed that up to 75% of flounders from sites in the Thames estuary had plastic fibres in their guts. The study included identification of main plastics polymers found in fish guts. Published in McGoran et al. (2017).

5.3.   These data were used in posters and at media launch of the Port of London’s Cleaner Thames campaign in September 2015 which served to highlight the issue of plastic debris pollution in the River Thames.

5.4.   Further studies are being carried out by a Master’s student at RHUL (in collaboration with NHM and Field Studies Council Millport) to compare plastic ingestion between Thames and Clyde Sea fish. Preliminary results show that out of 21 species, 16 ingested plastics. Overall between 33–47% of fish had ingested plastic with higher ingestion by flatfish species. Manuscript in preparation.

  1. We currently have a Master’s student working in close collaboration with the Zoological Society of London (ZSL) on OneLess campaign and Thames 21, including engagement with citizen science volunteers, specifically focussing on single use plastic water bottles. The aim is to describe deposition rates of bottles (floating debris) at five selected sites on the shores of the Thames by sampling every two weeks until early summer. These data (number of bottles and patterns seen at different sites) should be publically available in early June. Some general questions remain. There is a need to understand the accumulation of plastic debris in the benthic2 environment and sediment as, from our studies, bottom-feeding fish appear to accumulate higher levels of plastics.
  2. The role of trophic transfer3 of plastics from potential prey species to predators also needs exploring. Is there evidence that ingestion of plastic causes harm to fish species, and is there transfer of chemicals from plastic in the gut to other tissues?
  3. In relation to drinking water bottles and plastic cups, we need to understand what organisms are affected and how by these debris items. Simple questions, such as how the presence / absence of the top on the bottle affects likelihood of becoming floating debris versus sinking to the river bed.
  4. The key is to highlight the problem and encourage people to change their behaviour in order to reduce the volume of plastic debris in the environment and, through improved recycling, reduce the production of new plastic.
  5. I would be happy to provide further detail on this research should this be of interest to the committee.

 

References

McGoran, A.R., Clark, P.F. & Morritt, D. (2017) Presence of microplastic in the digestive tracts of European flounder, Platichthys flesus, and European smelt, Osmerus eperlanus, from the River Thames. Environmental Pollution Vol. 220: 744-751 http://dx.doi.org/10.1016/j.envpol.2016.09.078

Morritt, D., Stefanoudis, P.V., Pearce, D., Crimmen, O.A. & Clark, P.F. (2014). Plastic in the Thames: a river runs through it. Marine Pollution Bulletin Vol. 78: 196 – 200 http://dx.doi.org/10.1016/j.marpolbul.2013.10.035

Selected media links

https://youtu.be/hIILeXl0mKg

http://www.bbc.co.uk/news/science-environment-34408414

https://www.theguardian.com/environment/2014/jan/02/plastic-waste-thames-marine-life-report

http://www.london24.com/thames_plastic_waste_pollution_is_poisoning_river_fish_port_of_london_authority_fears_1_4592370

http://www.telegraph.co.uk/news/earth/wildlife/10547684/Plastic-litter-threatens-river-life.html?Social+Media&Twitter

http://www.independent.co.uk/environment/nine-out-of-10-flounder-swimming-in-the-thames-have-plastic-fragments-in-their-guts-says-research-a6677691.html

 

Footnotes

    1. Fyke net is a type of net typically used to fish for eels in the river Thames and elsewhere, typically comprising a central net wall with a cod-end at each end of this wall in which the catch collects. The nets are deployed on the river bed and fish for bottom-living species.
    2. Benthic environment – refers to the river (or sea) bed.
    3. Trophic transfer – transfer of materials / pollutants through feeding relationships between prey and predators.

March 2017