RMIT University’s satellite imaging tool can now effectively detect plastic on the beach, helping clean-up operations and the fight against ocean pollution. Researchers at RMIT University have developed a new satellite imaging tool that can detect plastic debris on beaches by analyzing how sand, water and plastic reflect light. This field-tested method allows you to detect plastic on coastlines from over 600 km away.

Satellite technology is already being used to track the large amounts of plastic floating in our oceans, from relatively small piles containing thousands of plastic bottles, bags and fishing nets to huge floating garbage islands like the Great Pacific Garbage Patch, which is three times larger. The size of France But this technology is less effective on beaches where plastic easily mixes with sand.

This is a recently published achievement. Marine Pollution BulletinIt provides an effective way to detect plastic on beaches where it is easier to access and remove through targeted clean-up efforts.

oceans of plastic

Currently, more than 10 million tonnes of plastic waste are dumped into our oceans every year, and it is estimated that this number could reach 60 million by 2030. The lead author of the study, Dr. Jenna Guffogg said plastic on beaches could have serious impacts on wildlife and habitats, just like in open waters.

“Plastic can be mistaken for food, with larger animals getting entangled and smaller ones like hermit crabs getting stuck in things like plastic containers,” he said. “Remote island beaches have some of the highest recorded densities of plastic in the world, and we are also seeing increases in plastic and abandoned fishing gear along Australia’s far northern coast.”

According to Guffogg, if this plastic is not eliminated, it will inevitably turn into micro and nanoplastics.

“While the impact of this ocean plastic on the environment, fisheries and tourism is well documented, methods to quantify the full extent of the problem or target cleanup operations, sometimes needed in the most remote locations, have been held back by technological limitations,” he said.

Technical details of the new detection method

The sandy plastic index the team developed is something called a spectral index; It’s essentially a mathematical formula that sorts the reflected light patterns collected by satellites as they pass over an area to reveal what you’re most interested in. you can see in the picture.

RMIT’s remote sensing team has developed similar tools to monitor forests and map wildfires from space.

The Beach Plastic Litter Index was designed to map plastic litter on beaches using high-resolution data from the WorldView-3 satellite, which orbits the Earth towards the Sun at an altitude of 617 km.

To test its effectiveness, 14 plastic targets, each approximately two square meters in area, were placed on a beach in South Gippsland, Victoria. Each target was made of a different type of plastic and was approximately 3 m2 smaller than the satellite’s pixel size.

Results and future expectations

Satellite images using the new index were compared to three existing indices, two of which were developed to detect plastic on land and one to detect plastic in water.

BPDI outperformed all three; others either had difficulty distinguishing plastic-contaminated pixels on the beach or tended to misclassify shadow and water as plastic. Co-author of the study, Dr. Mariela Soto-Berelov said BPDI’s improved separability from water as well as sand indicates that it is better used in environments where water pixels and plastic-contaminated pixels are likely to coexist.

“This is incredibly exciting because until now we haven’t had a tool to detect plastic in coastal environments from space,” he said. “The beauty of satellite imagery is that it can capture large, distant areas at regular intervals.

“Identification is an important step needed to understand where plastic waste accumulates and plan clean-up operations that align with various Sustainable Development Goals, such as protecting seas and oceans.”

The next step is to test the BPDI’s usefulness in real-world scenarios, Soto-Berelov said.

“We look forward to working with organizations in the next phase of this research; “This is a chance to help us protect sensitive beaches from plastic waste,” he said.