Plastics in the environment
Plastics are used in a plethora of applications because they are lightweight, durable, have excellent barrier properties and are relatively cheap. These properties also make inappropriately handled waste plastics a significant environmental threat. Plastic litter persists for many years, is readily dispersed by water and wind, and has been accumulating in the sea for decades. It entangles and is eaten by a wide diversity of marine fauna, killing them directly, or reducing their appetite. Concerns about ‘microplastics’ introducing persistent organic pollutants (POPs) into marine foodwebs, combined with the discovery of ‘garbage patches’ in all the main ocean gyres, has sparked renewed interest in the subject in the last decade.
Much remains to be learned about the threats that plastics pose to marine ecosystems, but we know enough to act to reduce the amount of waste plastic entering the environment. The most significant impacts of plastics on marine organisms arise from plastic ingestion, so it is important to understand why organisms ingest plastic. Tracking trends in plastic ingestion provides perhaps the best indication of the efficacy of mitigation measures introduced to reduce the amount of plastic in the oceans. However, it is not always feasible to sample plastic ingested by organisms, so we also monitor plastic in the environment, both at sea and washed up on beaches. Much of the recent research in this project has focused on understanding how plastics move through the environment, and how this affects estimates of plastic abundance.
Activities in 2017
- From December 2016 to March 2017, Peter took part in the Antarctic Circumnavigation Expedition (ACE), leading a project designed to assess the abundance and distribution of microplastics in the Southern Ocean. Most samples were processed in 2017, and a paper on the preliminary findings presented at the 6th International Marine Debris Conference in San Diego in March 2018.
- Meso- and microplastic samples were collected at 16 Mile Beach in the West Coast National Park as part of a study to assess the relative importance of mass and abundance as currencies for reporting plastic debris. This work also was presented at the 6th International Marine Debris Conference.
- Monthly clean-ups of intertidal litter at Muizenberg corner run in conjunction with The Beach Collective continued throughout 2017. The November 2017 clean-up saw a massive influx of sea-bed plastics – in order of magnitude more litter than recorded in any previous clean-up – providing further impetus to assess the abundance and distribution of sea-bed plastics in South Africa. Examination of more than 300 images of the False Bay sea bed collected by Lauren de Vos as part of her PhD with Prof. Colin Attwood yielded no visible litter items.
- Vonica Perold ran a project on sampling plastics at sea during the SEAmester at Sea cruise in July, obtaining excellent reviews from the student trainees on the cruise while also gathering valuable information on meso-and macro-plastic abundance on a transect west of Cape Town into the South Atlantic gyre. We also collected a valuable data set on plastics in the western Indian Ocean off Mozambique and Tanzania during the IOE II cruise of the SA Agulhas II in October-November.
- Peter Ryan gave several talks on plastic pollution to community groups, and other interested parties, including a well-attended talk hosted by Nedbank for WWF-SA and BirdLife SA in October, and was an invited speaker at the Volvo Ocean Summit, held in Cape Town in December.
- Also in December, given the strong focus of the UN Environmental Assembly in Nairobi on curbing plastic pollution, Peter was invited to be part of the French delegation to this meeting. He participated in a panel discussion as part of the formal proceedings, and gave a talk on microfibres in the marine environment in a fringe event on plastics in marine ecosystems.
- Two papers were published in 2017: one in Marine Pollution Bulletin on microplastic ingested by and adhering to the feathers of waterfowl, arising from Chevonne Reynold’s PhD, and one in Scientific Reports challenging a high-profile 2017 paper by Savoca et al. claiming that scent attraction contributes to plastic ingestion in seabirds.
- A paper summarising 20 years of meso-plastic sampling around the South African coast was accepted by Environmental Pollution, and published in early 2018.
- The collaboration with Dr Stefano Aliani’s group at CNR-ISMAR (the Italian Research Council’s Institute of Marine Sciences) in La Spezia was bolstered by ACE funds being used to help purchase a micro-FTIR system to identify microplastic fibres and fragments. ACE funds will also support PhD student Giuseppe Suaria after he completes his thesis.
- Recent UCT honours graduate and long-standing field assistant on this project, Eleanor Weideman, was recruited to undertake an MSc on freshwater plastic pollution in 2018.
- Peter Ryan was invited to attend the UN Environmental Assembly in Nairobi in November 2017 and was appointed a full member of the Scientific Committee for the Ocean (SCOR) working group on floating debris (FLOTSAM). He is a member of the UN’s GESAMP Working Group 40 which is now in its third phase, and tasked with harmonising methods for monitoring and assessment of marine plastics and microplastics.
Plastics SA, ACE Foundation.
Prof. Peter Ryan (FIAO, UCT)
Assoc. Prof. Coleen Moloney (MaRe, UCT)
Aaniyah Omardien (The Beach Collective)
Prof. Hideshige Takada (Tokyo)
Dr Stefano Aliani (CNR-ISMAR)
Guiseppe Suaria (CNR-ISMAR)
Field assistants : Vonica Perold, Mari San-Jacobs, Lucy Smythe, Eleanor Weideman.