Rain exacerbates plastic pollution

THIS month’s heavy rain was too much for a plastic garbage harvesting project in Durban’s uMhlangane River, part of a UKZN project to work out how much waste spews into the sea.

The heavy weather dislodged catching booms in the river, which starts in Inanda and passes through Phoenix, Ntuzuma and KwaMashu, allowing plastic pollution to enter the reeds of the Mgeni and wash up on the beaches.

“River mechanic” Bart Fokkens, environmental manager of the Dusi Umgeni Conservation Trust, said their teams had still “picked up 350kg on the beaches”. Lighter, but still significant, rain last month – 20mm – brought down 30 cubic metres of plastic that was gathered at the two catching points.

Dr Deborah Robertson-Andersson, of the UKZN School of Life Sciences, said that globally three metric tons entered the oceans every 15 seconds.

“Once the plastics reach the ocean, they are subjected to ultra-violet radiation and wave action and these two processes result in the breakdown of larger plastic products to smaller microplastics.”

She said that in South Africa there was a link between poor service delivery and plastic pollution. “Many communities use rivers as a means of waste disposal. This is the best of a bad situation for them and is unlikely to change in the near future.”

Robertson-Andersson added that although the booms were highly effective at trapping this plastic and preventing it from reaching the ocean, there were issues associated with them.

“They are still illegal, which means they are not permanent installations, thus are vulnerable to large rainfall events.

“They need to be permanently installed with breakaway options built in so they aren’t damaged in heavy rain,” she said.

When it comes to recycling, there was a need to find a use for dirty plastics because only clean plastic could be recycled.

“We are working with a company to generate funds to install a unit that would be able to use these dirty plastics and provide an economic incentive to set up more booms on more rivers.” It would cost R6.5 million to install.

“If we can think of waste as a resource and see that the rivers are delivering the waste to use the booms, then the problem is solvable,” Robertson-Andersson said.

However, she cautioned that while working on catching the small plastics was a great idea, it would not stop plastics getting to the oceans.

Fokkens said his structures on the uMhlangane River only caught plastic floating on the surface and not plastic bags, which were more often underwater. “They’re really bad. Turtles eat them,” he said.

“We are coming up with an idea of how to catch plastic bags in the water below the surface.”