According to a study conducted by researchers from the University of Western Australia (UWA) and CSIRO Wealth from Oceans Flagship, each square kilometre of Australian sea surface water is contaminated by around 4,000 pieces of tiny plastics that could affect humans as well as marine life.
Their study, which was published in the international journal Plos One, reported the plastic particles were mostly a result of the breakdown of disposable packaging and fishing gear made of polyethylene and polypropylene.
“These two polymers are commonly used to make everyday items, such as water bottles and plastic cups,” the study said, adding that Higher amounts of plastic were found close to cities on Australia's east coast, as well as in remote locations like west Tasmania and the North West Shelf.
The plastics detected during the at-sea surveys could contain hazardous materials as well as pollutants absorbed from surrounding waters, according to Julia Reisser, lead author and PhD student at UWA's Oceans Institute.
“There is increasing evidence that marine animals, ranging from plankton to whales, ingest large amounts of plastics loaded with pollutants, which may then be incorporated into the food chain,” Reisser said.
Previous studies have detected microplastics in the stomachs of southern bluefin tuna captured close to Tasmania and destined for human consumption, the study pointed out.
Australia's acknowledgement of plastic threats to marine ecosystems is mostly limited to the impact of relatively large debris including abandoned fishing nets and plastic bags on marine megafauna, such as turtles, mammals and birds, the study said.
According top Charitha Pattiaratchi, Winthrop Professor at UWA’s Ocean Institute, hotspots of plastics had been found offshore near highly populated areas as well as in regions where ocean currents converged.
Reisser said that results of the study demonstrated it was vital to take action to reduce marine pollution, especially given the threat. “We need to decrease plastic waste and toxicity, regulate plastic disposal on land at an international level, and better enforce the laws prohibiting dumping plastics at sea.”
Marine Plastic Pollution in Waters around Australia: Characteristics, Concentrations, and Pathways
Julia Reisser, Jeremy Shaw, Chris Wilcox, Britta Denise Hardesty, Maira Proietti, Michele Thums and Charitha Pattiaratchi