An analysis of plastic wastes on Australia’s beaches has found that the ocean itself is now a source of much of the plastic waste on Australia’s beaches.
The study by CSIRO found plastic waste in the ocean is making its way back to land where it is trapped by coastal vegetation.
This explains why estimates of waste entering the ocean each year are 100 times larger than the amount of plastic observed floating on the surface, according to the research agency.
A principal research scientist, Dr Denise Hardesty said: “We collected data on the amount and location of plastic pollution every 100 kilometres around the entire coast of Australia between 2011 and 2016.
“The highest concentrations of marine debris were found along the coastal backshores, where the vegetation begins.”
The results come as food producers and packaging companies get serious about utilising more recycled resources – resources often collected as litter or recycled by households rather than sent to landfill.
Utrecht University’s Arianna Olivelli, who led the analysis with CSIRO, said these findings indicate that coasts are a major sink for marine debris, particularly for larger debris items.
“The debris recorded along the coasts was found to be a mix of littering and deposition from the ocean.
“The results suggest that plastic is moving from urban areas into the ocean, and then being transported back onshore, and pushed onto land, where it remains.”
She said onshore wind and waves, together with more densely populated areas, influences the amount and distribution of marine debris.
“The further back we went from the water’s edge, the more debris we found.”
Wave activity has a much stronger effect than wind in determining where debris ends up.
These findings highlight the importance of including the entire width of coastal areas in studies to understand how much – and where – debris gets trapped.
This is critical for developing targeted waste management policies, particularly in areas with large regional populations, to reduce litter ending up in our oceans and along our coasts.
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