What’s in the water? Measuring the impact of plastic pollution

Multi-disciplinary research at Queen Mary, incorporating the work of polymer chemists, geographers, biochemists, microbiologists and environmental biologists, has led to new insight into these crucial issues. 

Quantifying plastic pollution

Professor Iwan Jones of Queen Mary’s River Communities Group is the Project Lead on the Preventing Plastic Pollution Project (PPP). The PPP project has adopted a catchment-based approach to understand the sources and impacts of plastic pollution, and to propose sustainable solutions to reduce it. By examining how the plastic arrives from source to sea, the project will identify and target hotspots for plastic and embed behaviour change in local communities and businesses to reduce the flow of plastic

PPP is developing a model to gather data from citizen scientists on the amount and likely sources of plastic pollution in nine areas across the Channel region. The information gathered in these areas will allow the cross-Channel partnerships to tackle some of the four million tonnes of plastic waste that enters the sea via rivers every year.

The €14m project was approved by the Interreg France (Channel) England Programme, which has committed €9.9m in funding through the European Regional Development Fund and involves 18 organisations including Defra, the Environment Agency, Office Français de la Biodiversité, a marine national park, regional councils and charities.

BioPEP seeks to understand biodegradable plastics

Traditional plastics, such as the low-density polyethylene used for plastic bags, are non-degradable, and scientists have worked hard to develop biodegradable alternatives such as crop-based hydrodegradable, compostable plastics and oxo-biodegradable plastic. 

In 2020 alone, 2.11 million tonnes of these new materials were manufactured. But how do these products break down? While lab testing shows promising results, how quickly do they degrade under natural conditions and what breakdown products do they produce? 

There is an increasing concern that biodegradable polymers may also be damaging for the environment. Like traditional plastics, they may not degrade completely and can thus form microparticles. They may also generate toxic metabolic by-products and impact on biota. The carbon they generate may be available to microbial communities. Currently, the wider impact on biogeochemical cycles is yet to be quantified.

The Biodegradable Plastics as emerging Environmental Pollutants (BioPEP) project seeks to evaluate the environmental impact of biodegradable plastics. Queen Mary’s interdisciplinary team includes:

• Professor Marina Resmini − Materials Chemistry
• Professor J. Iwan Jones −Freshwater Ecology
• Professor Kate Spencer − Environmental Geochemistry
• Dr Pavel Kratina − Ecology
• Dr Özge Eyice − Molecular Microbial Ecology
• Dr Emiliano Bilotti − Materials Engineering
• Dr Ruth Rose – Biochemistry

How can we measure the impact of these plastics on the environment?

Up until recently, it was extremely difficult to measure the scale of the problem.  Inconsistent methods were used to sample, measure and analyse the concentrations of microplastics in the environment. Reliable and consistent scientific data on the scale of the problem and the risk to the environment were needed to formulate policy to control microplastic pollution.

Between 2018 and 2020, Defra commissioned Professor Jones, together with colleagues including Professor Kate Spencer of Geography, to carry out a systematic analysis of reliable global data, looking at the analysis, prevalence and impact of microplastics in freshwaters and estuaries. There were three key evidence reviews, which asked the following questions:

• Are the current sampling and analytical methods scientifically robust and appropriate?
• What are the sources of the microplastics found in freshwater environments?
• What is/are the impact(s) of microplastics on freshwater and estuarine biota?

The reviews showed that: 

• “Scientifically robust and appropriate sampling and analytical methods have rarely been used to provide data on the presence of microplastics in freshwater and estuarine matrices. The review made various recommendations for future studies so that a more solid evidence based can be built in future”
• “At this time there is insufficient evidence to identify the sources of the microplastics found in freshwater and estuarine environments”
• “No studies provided evidence to suggest that microplastics had an impact on populations of aquatic organisms. Currently, there is insufficient evidence (particularly of damage in field populations associated with high concentrations of microplastics) to draw any conclusions regarding the impacts of microplastics on populations of freshwater or estuarine biota”

Professors Jones and Resmini also looked at the types of microplastics and where they are found in rivers and estuaries: it appears that biota might be avoiding certain types of microplastic. 

The research demonstrated the urgent need to standardise methods of monitoring microplastics and their environmental impact. They identified important gaps in our understanding of pollution sources and the fate of microplastics in the environment.

Sustainable Development Goals

Queen Mary's research on plastic pollution aligns with SDG 6: Clean Water and Sanitation, by addressing the critical issue of water contamination caused by plastics. The project focuses on measuring the impact of microplastics in aquatic ecosystems, highlighting how pollution affects water quality. This research contributes to developing strategies for reducing plastic waste in water bodies, ensuring cleaner, safer water systems for all. By advancing our understanding of plastic pollution, the project supports global efforts to protect water resources and promote sustainable water management.