Asia's plastic-polluted rivers pose a problem for Australia. So scientists are turning to drones

33 Drones used to identify pieces of plastic in the Mekong River.(Supplied: United Nations Environment Program)

31 MAY 2020 - Source: ABC News - It's one of 10 rivers in the world that collectively contribute up to 95 per cent of plastic in the ocean.

Running for more than 4,000 kilometres, the Mekong River flows through six countries, starting in China and making its way through Myanmar, Laos, Thailand, Cambodia and Vietnam.

It is used by millions of people and is home to a rich ecosystem. But now its pollution problem poses an issue for the region and Australia.

"Plastic pollution that originates along a river like the Mekong, may make its way out to the sea, and ultimately — given winds and waves and currents — that could end up on Australian shores as well," CSIRO principal research scientist Britta Denise Hardesty suggested.

"So whether you care about wildlife, whether you care about tourism or what's in your own backyard, the global nature of this problem means something over the other side of the world could end up in your backyard."

Long before the COVID-19 pandemic hit, scientists were working on a global plastic pollution survey backed by the CSIRO at a number of sites around the world to see how the issue was impacting on river systems.

For months, researchers have been studying plastic pollution at five sites along the Mekong River in South-East Asia, and along the Ganges River in India.

Preliminary results released his week show the Mekong River is suffering the most from plastic bottles and plastic bags being dumped in or nearby the precious waterway.

Yet even with the preliminary data in, scientists concede there could be an even bigger task ahead.

Identifying microplastics is extremely difficult so researchers have begun to look at alternatives.(ABC News: Amy Bainbridge)

 Now they're trying to quantify just how the COVID-19 pandemic will worsen the problem.

Kakuko Nagatani-Yoshida, from the United Nations Environment Program, said the pandemic meant there had been exponential growth in the use of single-use plastic.

"We are trying to have a better estimate to know how bad the impact will be," she told a news conference in Bangkok this week.

"Even before COVID-19, we knew that working on plastic pollution was really trying to solve this gigantic problem.

"On top of that, we all know that saving lives in a COVID-19 situation requires a lot of hygiene products, personal protection equipment at the hospitals and even at home."

Ms Nagatani-Yoshida said the sad thing was that for the majority of Asian countries, most plastic would likely wind up in landfill sites.

"We are afraid that much of the plastic waste is not even making its way to landfill, they're just simply being dumped into the environment," she said.

Back in February, the ABC was invited to have an inside look at the arsenal of technology being used by some of the brightest minds in the industry to quantify and solve the plastic pollution problem.

The "arsenal" involves two major technologies. One of them is drones.

Introducing the plastic-fighting drone

Drones used to identify pieces of plastic in the Mekong River.(Supplied: United Nations Environment Program)

They're able to capture thousands of images of plastic debris floating in and around the Mekong, which will then be used to identify individual pieces of plastic.

Those bits of plastic will then be given a geo-tag with a precise location, which is fed into a huge database that will help build a machine-learning algorithm to identify plastic pollution hot-spots on a broad scale.

Scientists and researchers say it's "revolutionising" the way environmental problems can be quantified and solved, simply by dramatically reducing the amount of time it takes to process information.

"It's a real game changer," Adam Hodge from the United Nations Environment Program told the ABC outside the Lao capital, Vientiane.

"If we were trying to assess the plastic pollution leakage sites or sources that we're looking at today with traditional methods, we could do surveys that could take five or 10 years.

"With the technology that we have now, we're able to get that information within a year or less.

"It's advancing our ability to tackle this problem at an early stage, and we know that we can't wait any longer to tackle this problem." 

Drone training for plastic identification along Mekong River.(ABC News: Amy Bainbridge)

Low-cost device sucks up plastics you can't see

While the drones can detect and photograph large pieces of plastic, there are plenty of smaller pieces known as microplastics (usually 5 millimetres or smaller) that can't be spotted from the air.

As a result, the Laos project is also using a Japanese-developed contraption called an Albatross to trap and study how much microplastic is getting into the river.

The chief executive of Japanese start-up Pirika, Kojima Fujio, said the Albatross sucked in the microplastics, which were then caught in a net and taken back to the laboratory for analysis.

All up, it takes about three minutes. 

The Mekong River flows through six countries, starting in China.(Supplied: United Nations Environment Program)

 "Many researchers are trying to find microplastics from rivers, but the common method requires using boats, and that's sometimes very costly," Mr Fujio said.

"So we decided to reduce the sampling cost and develop the portable device."

Ideally, they will then be able to trace the plastic product and where it was produced, and talk to plastic companies about potential changes to their product design.

"It's a very difficult process, and actually we've only succeeded to find 30 per cent of the product categories of microplastic," he said.

Identifying microplastics is still extremely difficult, but Mr Fujio said his team had some success already in Japan.

"For example, in my Japanese experience, we found 25 per cent of microplastics in Japanese rivers is actually from artificial grass from football grounds," he said.

"It's a huge problem that nobody knows about."

Mr Fujio said it was too early to know exactly what the main source of microplastic was in the Mekong, but he had some early indications.

"Maybe some of the microplastic comes from general waste like broken bottles and packages," he said.

Preliminary results show microplastics are abundant in the Mekong, and polypropylene is the dominant type of plastic found.

Polypropylene is a common plastic used in consumer packaging.

So how is this helping in the fight against ocean plastic?
A clearing filled with plastic rubbish and waste.(Supplied: United Nations Environment Program)

Mr Hodge said plastic waste filling our waterways and ending up in the ocean was a big issue that needed to be addressed.

"You have microplastics [and] larger pieces of plastic pollution getting into the environment, impacting ecosystems, potentially even getting into the food we eat, so this is a problem that's not far away," he said.

                                                                              "It's very immediate for large swathes of the population."

It's why Dr Hardesty says the benefit of this project is that instead of making assumptions based on models, "we're going out there and collecting real data".

                        "Rivers are hugely important because what flows along the rivers ends up out there in the oceans," she said.

"We're doing survey work along rivers and in inland areas as well, so we can find out how much debris is flowing down those rivers and ending up out there in our oceans."

Rajitha Athukorala, from the Asian Institute of Technology, said the drone technology was exciting, and using machine learning to help the environment was a huge motivation.

He explained that the algorithm researchers were working on was also being developed using open source data, such as population density and river flows, to help to identify where and why plastic was seeping into the Mekong River in Laos.

"So population, the hotels, and the impact from different festivals, like tourism, all this will [be looked at to] try to pick up the hotspots," Mr Athukorala said, adding the data would be used to pick and validate their model.

Once the team can identify hotspots, they will look at localised solutions that can be scaled up.

It may be as simple as providing more garbage bins in an area frequented by tourists, or working with different councils to improve waste-management systems.

"We need to go out there, ask the questions, collect the data we need, and when we have that information we're able to make smart decisions," Dr Hardesty said.

"Then we can figure out the best places to have interventions all along the way."

She pointed out that while there was "no single silver bullet" to addressing the issue, having information from many different cities and countries around the world would allow the CSIRO to identify solutions that were likely to be most effective.

"It's important for solutions to be workable in a particular cultural and social environment, so you can't just have a once-size-fits-all solution for every component of the problem." 

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