Butt Out: A transdisciplinary approach in understanding and addressing the risks of littered cigarette butts

Project Background
Marine litter, particularly plastic debris, has been demonstrated to be a timely, global, and important issue to address. However, to extend this research into effective solutions, expertise from different disciplines needs to be brought together. Cigarette butts are one of the predominant types of litter identified on coastlines worldwide. In the UK, the Marine Conservation Society's annual citizen science survey determined that cigarette butts are consistently found in the top 5 litter items on UK beaches. The abundance of certain beach litter items in the UK e.g. cotton bud sticks and carrier bags have decreased as a result of policy interventions. However, the amount of cigarette butts found on beaches remains high and during the GBBC annual September beach clean in 2021, it was found that cigarette butts on Welsh beaches were at their highest levels ever recorded. Cigarette butts are considered to be a type of plastic debris, as cigarette filters comprise microfibres made from the bioplastic cellulose acetate. Such litter is an eyesore and can have negative impacts on beach visitors' experiences. Further, cigarette butts may pose harm to marine life, as each filter can release copious amounts of microscopic fibres that can be readily ingested by animals. Plastic microfibres can cause adverse health effects in marine organisms, and there is concern that fibres stemming from cigarette butts, infused with a cocktail of chemicals associated with cigarette smoke, may pose an even greater toxicological risk.

Project Aims and Methods
In this PhD, the student will undertake pioneering transdisciplinary research to explore the extent to which cigarette butts contaminate beaches, better understand the harm cigarette fibres can have on marine life and elucidate the behaviours resulting in beach littering, with a view to identifying and optimising suitable interventions to littering of cigarette butts. The student will work with the supervisory team to co-develop methodologies that help address the following research questions:

Task 1. What is the extent of the problem?
Guided by MCS' extensive datasets to identify hotspots, the student will have opportunities to conduct sampling, processing and analysis of environmental samples for cellulose acetate fibres associated with cigarettes, which are too small to be observed via the MCS' existing visual surveys. The data will elucidate the prevalence of microfibres associated with cigarette butts along UK coastlines.
Task 2. What are the ecological risks?
The student will employ ecotoxicological methodologies to determine the harm that cigarette filter fibres can have on ecologically important marine invertebrates, such as the pelagic copepod Acartia tonsa. Exposure studies will use cellulose acetate microfibres and leachates prepared from unsmoked, smoked and weathered cigarettes across a wide range of concentrations. Toxicity thresholds can be combined with prevalence data (Task 1) to calculate ecological risk.
Task 3. Why do people litter cigarette butts?
The student will critically examine previous work conducted in health and environmental psychology, examining what is currently known on the key drivers of littering behaviour when it comes to cigarette butts. The student will then extend this work either by running meta-analyses to identifying the most influential drivers (generally and in a beach context), or if gaps remain, conduct primary research (e.g. a questionnaire survey on smokers).
Task 4. How can these findings drive forward an effective intervention?
The student will address how cigarette butt littering on beaches can be addressed effectively. They will start by conducting a literature review in both the grey and scientific literature to understand what interventions have previously been tested and their effectiveness. They will then concentrate on testing a suitable intervention.