Microplastics big threat to marine health
Tiny ‘nurdles’ don’t biodegrade in ocean, contaminate food chain
THEY may be tiny, but microplastics pose a big threat to South Africa’s pristine network of marine protected areas.
This is one of the findings of a study which warns how the poor management of waste could put the country’s 24 protected areas at risk from harmful microplastics, affecting marine fauna.
Microplastics refer to nurdles – small plastic pellets, microbeads from cosmetics and toothpaste, fragments of plastic and microfibres from garment and carpet-making – that can contaminate the food chain.
The study by a team of scientists from Rhodes University and published in Marine Pollution Bulletin, says the ill-management of waste in localised areas will have a national effect because of ocean currents.
“Due to their minute size, this type of pollution is not necessarily visually unappealing. However, it has major mechanical and chemical i mplications,” says the team in “Do microplastic loads reflect the population demog r aphics along the souther n African coastline?”
One of the a ut hors, Dr Holly Nel, a post-doctoral fellow at the department of zoology and entomology, says: “In microplastic research we often try to understand the source/ sink dynamics, so where did it come from and where does it end up?
“This helps us stop the problem at the ‘source’ and allows us to clean up at the ‘sink’. For example, if there is ill-management in Durban and a large amount of waste and microplastics leak into the marine environment these items/particles can be distributed long distances by ocean currents. This results in items eventually being stranded on uninhabited islands or protected areas further along the coast.
“Another is how inland municipalities with poor waste management infrastructure can be a source of waste leaking out into the aquatic environment. During high rainfall items/ particles can get washed down the rivers/estuaries into the marine environment far from the original source.”
This makes management difficult as litter not only crosses ecosystems but countries and continents. “There is so much we don’t know about what gover ns microplastic distribution, but that’s why it is so important to manage our waste everywhere and not just in coastal towns and cities.”
Last week at the African Marine Waste conference, the scourge of these plastic particles was a leading topic. “Africa is data scarce and microplastic research is very labour intensive,” says Nel. “With the information from the workshop we will start developing large collaborative projects and monitoring strategies that will hopefully attract funding.”
Experts say persistent organic pollutants attach to these tiny plastic particles, tur ning them into chemical hazards in the food web.
The researchers investigated the microplastic burden of beach sediment and surf zone water at sites along the country’s coastline.
They found microplastic particles were “a ubiquitous contaminant found in all water column and sediment samples, collected from both sandy beaches and enclosed harbours along the coast. The presence of microplastics was expected, as the widespread distribution within the marine environment is now well documented. Densely populated areas are recognised as a major landbased source of microplastic contamination, through the fragmentation of directly or indirectly discharged plastic debris and the poorly regulated discharge of domestic and industrial effluent.”
The elevated loads at the Richard’s Bay and Durban Bay systems “likely reflects the contamination by significant amounts of plastics derived from inland sources.
“Harbours have been classified as a major sink for plastic pollution, and consequently sources of pollution for outlying coastal regions.”
Nel salutes the global Operation Clean Sweep. “This is an amazing initiative that reduces the spilling or leakage of plastic nurdles through education and awareness with industry and factories,” she says.
Douw Steyn, the sustainability director at Plastics SA, says the primary goal of the campaign is to stop plastic pellets, flakes and powder, from reaching the sea.
“We, as the plastics industry, produce the pellets and flakes used to manufacture plastic bags, bottles and other plastic products. When these raw material/pellets are spilt during the manufacturing process, they are swept into drains from where they enter the sewage system and end up in our rivers and the sea.
“These pellets are smaller than a sunflower seed in length, but wider and are therefore not easy to pick up during regular beach clean-ups. Our goal is to achieve zero pellet, flake, and powder loss. While it might seem an ambitious target, we believe it’s possible through containment and the implementation of good housekeeping practices.”