Redbank Creek is choking on plastic, with a university student finding a shocking 10 per cent of material in the water at North Richmond is microplastics.
Final year Bachelor of Natural Science (Environmental Management) student at Western Sydney University, Justine Wade, conducted the research as part of her work for the Water in the Landscape unit.
Ms Wade took three soil samples and swept an algae net through the creek to obtain a water material sample under the bridge near the North Richmond wastewater treatment plant, drying the samples in an air oven overnight and sieving them to remove any material over five millimetres.
Viewing her results under a microscope, Ms Wade was physically unable to count just how much plastic was present in the water material sample.
"I couldn't correctly count the amount of microplastics in the water material sample due to the huge amount that was in there," she said. "I knew there was going to be a lot of plastic in it because the spot I tested had things like a kid's swimming pool and bottles dumped in it.
"[But] the plastics were so intertwined and connected that I didn't know where one started and ended.
"I gave a percentage because I could not actually count it. I ended up with a percentage count of 10 per cent, [meaning] 10 per cent of the material found in the water at that specific location was microplastics. This would result in 100mg of plastic per kilogram of suspended water particles."
Ms Wade also found a total of 11 microplastics in the 30mg of soil she tested, meaning 366 microplastic particles were present in a kilogram of soil in the area.
Microplastics are any plastics with a diameter smaller than 5mm, which can include microbeads from beauty product exfoliants, micro fibres from clothing, or just some of the millions tonnes of plastics that get broken down into small particles by sunlight, waves, heat and currents in rivers and oceans.
Ms Wade said high levels of microplastic in the water material harmed aquatic animals and, in turn, affected other predators.
"Microplastics block digestive tracts, diminish the urge to eat and can cause abnormal growth in aquatic animals who may ... ingest this," she explained. "This ultimately causes a domino effect, which creates problems for those predators eating the prey, and so on."
Comparison data taken upstream of the original samples showed just two microplastics in the 30mg sample - or 66 microplastics per kilogram of soil - meaning areas where there was less development had 5.5 times less mircoplastics, she said.
Ms Wade, from East Kurrajong, is hoping her research leads to a greater awareness of the use of plastic in the Hawkesbury.
"The less plastic you use, the better," she said. "A lot of stormwater goes into that creek, so a lot of plastic from the streets of North Richmond ends up in the creek."
