Predicting the Polymer-specific Fate of Aquatic Plastic Litter

The amount of plastic litter in in the environment is growing rapidly. Its presence poses a severe threat to marine and freshwater life. However, at the heart of our knowledge of plastic litter lies a black hole. The location of 99% or more of the plastic litter thought to be in the ocean is unknown. This makes it difficult to propose effective solutions for the problems associated with plastic litter. The main goal of this project is to predict what happens to different types of plastic litter in the environment. To achieve this, the degradation of commonly used plastics will be monitored under controlled laboratory conditions. Experimental methods to produce tiny fragments of plastics made from different polymers will be developed. These will be used to simulate their behaviour in the environment. For example, how quickly they fragment and sink under different conditions and how easily they transfer from water to river sediments. For comparison, plastics which are thought to degrade in a more environmentally-sustainable fashion will also be monitored. Results from these tests will be used to predict the fate of different types of plastics in the environment. They will also allow an assessment of the contribution that promoting sustainable types of plastics can make to solving the problem of plastic litter in the environment.

Who are the potential beneficiaries of this research and how might they benefit?

The UK plastics industry, which has a turnover of £23.5 billion and is aware of the need to increase the environmental-sustainability of its products. An improved understanding of where different polymers accumulate in the environment and their predicted impacts will help the UK plastic industry to develop more sustainable products and validate their sustainability under controlled laboratory conditions. Letters of support from Aquapak, Nextek and Polymateria demonstrate the relevance of this project to the UK polymer industry. One specific example is that methods and results from the project can contribute to the preparation of a new standard method to assess the environmental fate of plastic samples in aquatic systems. See letter of support from Dr Chris Wallis of Polymateria, who sits on the Plastics in the Environment committee of ASTM International (formerly the American Society for Testing and Materials).

The UK water industry, who will benefit from improved understanding about the fate of different types of polymers during wastewater treatment, illustrated by an attached letter of support from Thames Water.

The multidisciplinary academic community, who will benefit from a comprehensive knowledge base about how to generate polymer fragments across a range of particle sizes and their physicochemical properties are. Particular beneficiaries may include those (1) modelling the transport and fate of plastic litter in different environmental compartments (2) studying the ecotoxicological effects of plastic particles (3) seeking to design novel polymer formulations which degrade in an environmentally-benign fashion and (4) developing standardised analytical methods to isolate and identify plastic particles in environmental samples. Erik van Sebille, Associate Professor at Utrecht University, has expressed a willingness to collaborate on points (1) and (4) and more broadly to utilise his own professional network in order to facilitate follow-up research from this project (see letter of support).

The general public, who are acutely concerned about the harmful effect of plastic litter and keen to see solutions to the problem developed. They will potentially benefit from improved knowledge about which types of polymers are more or less harmful in the environment and how the UK plastics industry can demonstrate the sustainability of their products.

Impact goals
1. Organise a workshop on the Solutions to plastic litter towards the end of the project. Amongst other topics this workshop will discuss whether the UK plastics industry would benefit from having an accredited sustainability label on plastic products, awarded to polymers demonstrated to degrade in an environmentally-benign fashion. The steps required to achieve this will be defined and one invited speaker will share their experience of the process of gaining accreditation for a consumer product. Attendees will include project partners and other representatives of the plastics industry.
2. Publish three papers detailing results from the project, one for each work package. The first will demonstrate how standardised degradation protocols developing during the project can be used to quantify fragmentation rates for representative classes of plastic litter. The second will comprehensively characterise the physiochemical properties of polymer fragments and use this data to predict the environmental fate of plastic litter. The third will be a position paper addressing the question of how polymers can be engineered to make them environmentally-sustainable.
3. Present project findings at two international conferences on microplastics, to forge links with researchers in complementary fields.
4. Develop an outreach activity asking members of the public what they think are the best solutions to plastic litter, which will be shown at University of Surrey applicant days.