In May 2018, the first full-scale mobile marine plastics collection system, developed by The Ocean Cleanup, will leave San Francisco, California, bound for the ‘Great Pacific Garbage Patch,’ also known as the Pacific trash vortex. The plan, ultimately, is to use 60 of these $5m systems to clean up half of the debris in the Pacific Garbage Patch within five years, according to Boyan Slat, CEO of Netherlands foundation The Ocean Cleanup, speaking at the Cefic Chemical Congress held in Vienna, Austria, at the end of October 2017.
Each collection system comprises a 1km U-shaped barrier, which floats on the surface of the ocean and supports a 4m deep screen to channel floating plastic debris to a central collection point, for future recycling. A 100m prototype system has already been tested in the North Sea.
The system will leave from the San Francisco bay area. Image: Giuseppe Milo
The environmental cost of the Pacific’s plastic waste currently stands at roughly $13bn/year, while an estimated 600 wildlife species are threatened with extinction partly as a result of ingesting it. Plastic microbeads and particles only represent 5% of the plastics in the oceans, ‘but the remaining 95% will break down into small particles and chemicals that are already in the tuna we eat,’ Slat said. The larger plastics debris are all found in the top 4m of the oceans, the same depth as the system’s screens.
Plastic debris can end up in the food we eat. Image: Pixabay
Also speaking in Vienna, Emily Woglom, executive VP, Ocean Conservancy, said that 8m t/year of plastics goes into the oceans – ‘one city dump truck every minute’; between 2010 and 2025 the amount in the oceans will double. As much as ‘30% of fish on sale have plastics in them,’ she said. Most of the plastics now come from the developing economies, mainly in Asia, she added, noting that the Trash Free Seas Alliance, founded by the Ocean Conservancy and supported by the American Chemistry Council, Dow Chemical, P&G and the World Plastics Council as well as several big-name food and beverage companies have recently adopted the goal of launching a $150m fund for waste management in South East Asia.
How we roll. Video: The Ocean Cleanup
Meanwhile, Slat says that the mobile collection systems can also be used to trap plastic pollution closer to the source, for example in rivers and estuaries. Researchers at The Ocean Cleanup estimate that rivers transport between 115 and 241 m t/years of plastic waste into the oceans, with two-thirds coming from just 20 rivers, mostly in Asia.
The Pacific trash vortex forms as a result of circular ocean currents created by wind patterns and the forces created by the Earth’s rotation. Similar gyres are found in the South Pacific, Indian Ocean, and North and South Atlantic.