In a new study from RMIT University, researchers used infrared signals that bounce off plastic particles to identify debris along the shore. The goal is to find ways to remotely track down waste on the coast to clean it up. The new method would allow plastics to be identified in a satellite image in which the plastic is smaller than a single pixel.
“Marine plastic debris (MPD) is a globally relevant environmental challenge, with an estimated 8 million tons of synthetic debris entering the marine environment each year,” wrote the study authors.
“Plastic has been found in all parts of the marine environment, including the surface layers of the ocean, within the water column, in coastal waters, on the benthic layer and on beaches.”
“While research on detecting MPD using remote sensing is increasing, most of it focuses on detecting floating debris in open waters, rather than detecting MPD on beaches.”
Study lead author of the study and PhD candidate Jenna Guffogg explained that looking for trash on beaches makes more sense than searching in the ocean, simply because it’s easier to clean up.
“Stopping plastic from entering the ocean is a global challenge. But if we can find and remove them quickly, it’s the next best thing,” said Guffogg.
“At the moment, plastic debris are tracked by passing vessels notifying authorities. Using satellites will allow more frequent and reliable observations.”
“Our work could let organizations who do remote coastal and marine waste clean-up management know where to focus their efforts.”
Guffogg and her colleagues completed field trials on isolated beaches in Australia’s Cocos (Keeling) Island using sensing equipment to see how infrared reflected off different types of plastic debris washed up on shore.
The team compared the results with the same tests on new, undamaged plastics and found little difference. This means that many different types of plastic – regardless of color, shape, texture and weathering – can be detected. The next step is to improve the ability of the imaging system even more.
“In the next few years, we’re going to launch satellites with even better remote sensing capabilities,” said Professor Simon Jones. “We’re developing ways to use these new satellites in the fight against marine waste.”
The study is published in the journal Remote Sensing.