BIO-PLASTIC-RISK: biodegradable bioplastics – assessing environmental risk

Research to establish the fate of biodegradable bioplastics (BBPs) in the environment and their effect on organisms and ecosystem function
Crops in a farmed field covered by protective sheeting
 

Summary

Biodegradable bioplastics (BBPs) are generally considered an environmentally sound alternative to conventional plastics. However, despite increasing quantities of bio-based products being produced and sold globally, there has been little research to assess their potential impact on species and ecosystems.
Led by the University of Plymouth, BIO-PLASTIC-RISK brings together our internationally recognised polymer scientists, marine and terrestrial biologists and ecotoxicologists with co-investigators at the University of Bath and Plymouth Marine Laboratory.
Collectively the team aimed to establish the fate of BBPs in the environment, their effect on organisms and ecosystem function, and to develop environmental risk assessments. The research will be used to guide development of future BBPs and provide clear, reliable information on the benefits and risks of using them.

Objectives

  • Characterise BBPs in terms of their composition (chemical structure, additives) as well as features that can be used to assess deterioration (molecular weight, thickness, strength) in the environment
  • Establish the fate of BBPs in marine and terrestrial environments in terms of rates of deterioration as well as the pathways and environmental accumulation of BBPs and their breakdown products
  • Examine any associated direct effects of BBP deterioration on marine and terrestrial organisms (animals such as mussels and earthworms and plants such as herbs and grass) and examine any indirect consequences on ecological and biogeochemical processes
  • Use this information to evaluate the fate, hazards and risks of BBPs in the environment and at what concentration levels they may have an impact on animals, habitats and ecosystem function.

This is a truly ground-breaking project. For years, biodegradable materials – including plant-based bioplastics – have been highlighted for their potential to reduce the environmental impact of packaging waste.

However, there hasn't been the detailed research to identify precisely how that might be achieved. Through this project, we hope to establish, in the open environment as opposed to managed waste systems, what works and what doesn't, in terms of the materials' characteristics and effects. 
But we can also explore how best to bring about the changes required to move from our throwaway society and help maximise the benefits of plastics without the current levels of largely unintended environmental and economic impacts. 

Richard Thompson OBE FRSProfessor Richard Thompson OBE FRS
Director of the Marine Institute

Microplastics in soil

Context of the issue

BBPs are a category of materials that offer considerable potential to reduce the global environmental challenge resulting from the accumulation of end-of-life plastic. BBPs are made from renewable carbon and, as a consequence of their molecular structure and resulting properties, are regarded to have enhanced rates of biodegradation compared to conventional plastics.
BBPs are already widely used in applications with substantive pathways to the natural environment (e.g., agricultural mulch film, textile fibres, microbeads in cosmetics). Yet our understanding about their fate in the natural environment is poorly understood because key information on the kinetics of degradation and any potential environmental effects of their breakdown products is lacking. Biodegradation has been demonstrated under specific conditions, such as commercial compositing, and there are associated standards, but studies indicate degradation can be slow or incomplete under natural conditions.
Earthworm Lloyd Russell

How the project addresses the issue

The researchers conducted a study testing the effects of conventional polyester fibres and two bio-based fibres – viscose and lyocell – on earthworms. They found that in high concentrations of fibres, 30% of earthworms died after 72 hours when exposed to polyester, while those exposed to the bio-based fibres experienced much higher mortality of up to 60% in the case of lyocell and 80% for viscose.
A second experiment, using environmentally relevant concentrations of the fibres, indicated that earthworms housed in soils containing viscose fibres exhibited reduced reproduction compared to those exposed to polyester fibres. Earthworms in the soils containing lyocell fibres showed reduced growth and also higher rates of burrowing within the soil compared to exposure to the other types of fibre.
The study highlights the complex nature of global efforts to reduce the threat of microplastic pollution, and the importance of testing new materials being advocated as alternatives to plastics before they are released on the open market.
A microscopic image of lyocell fibres captured at the Plymouth Electron Microscopy Centre Plymouth Electron Microscopy Centre
A microscopic image of lyocell fibres captured at Plymouth Electron Microscopy Centre
 

International Marine Litter Research Unit

Marine litter is a global environmental problem with items of debris now contaminating habitats from the poles to the equator, from the sea surface to the deep sea.
Furthering our understanding of litter on the environment and defining solutions.
Marine litter