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UKZN begins research project with The Ocean Cleanup to tackle Umgeni River plastic pollution

The project will span three years, mapping plastic pollution hotspots and fluxes in the river and along the Indian Ocean coastline.

The University of KwaZulu-Natal has teamed up with The Ocean Cleanup – a Dutch non-profit developing advanced technologies to rid the oceans of plastic – to investigate the mechanisms of plastic pollution in the Umgeni River and its transportation through all seasons.

"This is a project about mapping, trapping, collecting, processing, testing, modelling and engaging," said South African Research Chair (SARChI) for Waste and Climate Change, Professor Cristina Trois, who is lead investigator on the project along with colleague, Dr Thomas Mani from The Ocean Cleanup.

"How many plastic items have you used today already? Are you possibly using one just now? The answers are very likely 'many' and 'yes',’ said Mani.

Trois said this was not surprising considering plastic’s roaring success through the global markets starting in the 1950s. Today, more than 400 million tons of plastic products are purchased every year worldwide.

Acknowledging the many benefits these materials have brought to the modern world – for example in sterile medicine, lightweight automotive and aviation – at the end of their use, plastics pose a vast environmental problem, said Trois. "Of the total of over eight billion tons of plastics ever produced to date, a staggering 80% have already ended up in landfills or the environment. Once lost, plastics will fragment into smaller pieces – microplastics (<5 mm) – which pose a threat to ingesting organisms."

Rivers are believed to be major pathways for plastic waste on land to reach the oceans. A brand new global modelling study indicates that 0.8 – 2.7 million tons of plastics are transported towards the oceans yearly, with small urban rivers among the most polluting. According to this study, five major streams in the Durban area may carry as much as 1 340 tons alone towards the Indian Ocean. Among these is the beautiful but plastic-infested Umgeni River (estimated 380 tons per year).

It still largely remains a mystery what the true anthropogenic and environmental mechanics are which drive this riverine plastic transport, said Mani. "For this reason, empirical physical evidence is needed to support the current model data. When and how do plastics spill into the Umgeni? How fast and how far will they be flushed downstream? How much and when will the plastics reach the river mouth and the Indian Ocean? What happens after these drink bottles, shopping bags and lunch boxes reach the ocean?"

These are some of the main questions that Trois is trying to answer. With her team of researchers, she has partnered with Mani, Lead River Field Scientist in the research department at The Ocean Cleanup.

Together, UKZN and The Ocean Cleanup research department are embarking on a three-year research project from 2021-2024 to map plastic pollution hotspots and monitor plastic fluxes in the Umgeni River catchment as well as on the coastline of the Indian Ocean around Durban.

"From the belief that you need to understand a problem to be able to truly solve it, The Ocean Cleanup pursues a strong research emphasis in line with its mission to rid the world’s oceans of plastic by deploying mechanical clean-up devices in the offshore ocean as well as in rivers," said Mani.

With the use of satellite imagery, airplanes and drones, river cameras, floating GPS trackers, “litter-boom” waste characterisation, underwater sampling and beach litter characterisation, this research partnership is specifically seeking to find new insight into the seasonal dynamics of plastic waste transport through the Umgeni River system and provide a replicable model for cities in the West Indian Ocean (WIO) region.

To kick off this exciting research voyage, a workshop was held between all involved stakeholders, including UKZN, The Ocean Cleanup, the National Department of Science and Innovation (DSI) through the RDI Waste Roadmap, eThekwini municipality, The Bateleurs, Durban Green Corridors and Sustainable Seas Trust (SEAS).

A team from The Ocean Cleanup including Dr Mani joined UKZN researchers for the initial mapping flight over the Umgeni River catchment on 27 May with a light airplane provided by The Bateleurs, a non-profit group of volunteer pilots who avail their aircraft for conservation causes.

Contact: Professor Cristina Trois, [email protected]; (082) 346 2644

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