UCT student researching river pollution

A litter boom at Liesbeeck River.

What sort of litter gets into our rivers? A UCT student hopes to shed some light on that with the research he is doing.

Kyle Maclean, of Vredehoek, is working with The Litterboom Project and assessing the types of litter passing through the Liesbeeck, Black and Lotus rivers as part of his research for his Master of Science degree.

The Litterboom Project – which uses floating pipes to trap litter in rivers -was founded by Cameron Service in 2017 to stop plastic pollution in Cape Town’s rivers and oceans. At least 90% of marine plastic pollution comes from rivers, which is why the project focuses on finding solutions to river pollution.

Mr Maclean, who is also a member of the Friends of Liesbeek, is recording the steps taken to stop plastic pollution in the city’s main waterways and assessing how effective litter barriers are.

“This research project provides me with valuable work experience and helps supplement my studies through part-time work,” he said. “It gives me the opportunity to work with other organisations, outside of research, who share the same goal of reducing plastic pollution in our environment.”

Winter rains carried a lot of waste into rivers and canals through the stormwater systems, and some 100 to 200 bags of litter were being removed from the barriers every week, he said.

Polystyrene, food packaging, chip packets, sweet wrappers, bottles, plastic straws and carrier bags are common among the retrieved waste.

“Waste that is already in the river is then prevented from moving with the increased flow of the water as well,” he said.

UCT’s Professor Kevin Winter, who is also involved with the project on Liesbeeck River, said: “This project is about trapping a small portion of the litter so that it can be identified, weighed and improve our understanding of where it originates. Large items are probably obvious, but there are many large numbers of items that are small such as cigarette butts and plastic straws.”

Professor Winter said he doubted that anyone driving on the N2 and M5 alongside the Black River had not seen the mass of litter in the river.

“I am grateful for efforts of community groups who are cleaning the Black River and the City that removes litter from channels that are feeding the Black River. These efforts are clearly not enough, but the conditions of the Black River would be uncontrollable without these interventions. Ultimately the litter that we see in the river is destined for the sea,” he said.

According to Mr Maclean, there is limited data on plastics in South African freshwater systems and better estimates are needed of how much land-based plastics and wastes end up in the sea.

“We began sampling with the onset of winter rain and will continue until it subsides. We typically sample for several days following a rain event to get an idea of what is coming down the river and then ‘process’ it on campus – recording dry weight and any information relating to litter type, size, branding and dates of manufacturing/expiration,” he said.

He hopes the work will give a better idea of which trap designs work best and how effective they are for different types of litter.

“These findings will be shared with the operators of existing screening systems so that they can improve the efficiency and sustainability of their operations,” he said.

Kyle Maclean installing a litter boom in the Liesbeeck River.