MICROPLASTICS AROUND AUSTRALIA
Plastic pollution is now recognised as one of the world’s most pressing environmental issues. However, with increasing plastic production, and approximately 12 million metric ton leaking into our oceans annually, plastic pollution is a rapidly growing problem.
Over the past decade, there has been significant attention given to macrolitter. However, microplastics (plastics < 5mm) are now considered a greater concern, with scientists calling for them to be listed as a hazardous substance.
Of the numerous recognised impacts to wildlife from marine litter, over 70% can be attributed to microplastics, and with their ability to move through the food chain, effects are compounded.
Microplastics in Australia
In Australia, there is little known on microplastic levels or their impacts - this is where AUSMAP takes part.
As part of the global first, nationwide citizen science project, our volunteers have sampled over 300 shorelines across Australia (both coastal and freshwater)
- over 3,000,000 microplastics already collected!
Here are some results for selected frequently sampled sites and regions.
South Australia is home to two microplastic hotspots with the highest loads found in Australia, Port Adelaide and West Lakes.
West Lakes- Adelaide
During 2019, our volunteers collected data from around West Lakes, a semi-enclosed estuarine system in Adelaide, South Australia.
Results across these locations have consistently recorded the highest microplastic loads in Australia, indicating a widespread distribution of the problem.
Values from these sites were between 5500 and 9500 microplastics/m2, far in excess of the next highest values collected from a Sydney Harbour beach (~1600 mps/m2)
It is estimated that at one of these beaches, there are at least 2.5 million microplastics!
Map of West Lakes, South Australia. Black points indicate very high microplastic loads (> 1000mps/m2).
Chart showing the type of microplastic at West Lakes.
THe coast of queensland
During 2019, data collected by our volunteers & those part of the ReefClean program, have found
low loads of microplastic along the Queensland coast.
The highest levels were found in the Burdekin Dry Tropics region near Townsville with 27 mps/m2 - made up of mostly hard plastic fragments and polystyrene foam.
Graph illustrating trends of microplastic loads per m2 on average across Qld regions.
Error bars are Standard Error of the Mean.
The relatively low levels of Queensland are a promising result but more data, particularly around Brisbane and the southeast, is needed to give a more definitive idea of microplastic loads in the state.
Map of microplastic loads along Queensland Coast.
Green points indicate very low levels (<10mps/m2) and yellow points low levels (10-50mps/m2)
NEW SOUTH WALES
As Sydney is home to the AUSMAP head office & the largest number of citizen scientists involved in the program, we have the greatest number of sites sampled per area.
Data shows the variable nature of the microplastics in the region with loads ranging from low to very high, some of which are only relatively short distances apart. These differences are driven by local currents, shore aspects, and physical features.
Harbour sites were found to consistently have moderate to high microplastic loads pointing to this catchment as a major source to the nearby coast.
Similarly, the Cooks River which flows into Botany Bay was found to have very high microplastic loads near its mouth and would be another major source into the nearshore environment.
Microplastic loads collected during sampling in 2019 around Sydney.
Monthly microplastic data, collected from Manly Cove by our Community Champion Ali, has shown that the levels and types vary not only spatially but also temporally.
Numbers spike after certain weather events but remain relatively consistent at moderate to high levels outside of these times. Not only do numbers vary but types of microplastic change over time.
A trend of hard plastics dominating the warmer months and polystyrene foams are found more often in cooler months, which may suggest weather and catchment or water-based activities may be influencing factors.
Graph showing changes in microplastic amounts at Manly Cove, Sydney over time
Graph showing changes in microplastic types as a percentage at Manly Cove, Sydney over time