After five years of planning, testing and revising, the Ocean Cleanup (Delft / The Netherlands; www.theoceancleanup.com) is preparing for its first “real world” test – see Plasteurope.com of 03.04.2013 and 10.10.2016. The nearly 600-metre array, which is sometimes described as a tube that functions as a floating coastline, will be launched on 8 September 2018 from a dock in Almeda, California / USA, where it is currently being assembled. The Ocean Cleanup has a YouTube video explaining the collection process, and the launch will be live-streamed. If successful, the marine vessel will be towed 1,536 km to the “Great Pacific Garbage Patch” (GPGP) between California and Hawaii. Up to 2020, it is planned to be joined later by 60 such systems. The ambitious goal – of which many experts are sceptical – is to clean up 50% of the mainly plastics waste in the gyre within five years.

According to an estimate published by Ocean Cleanup earlier this year, 1.8 tr pieces of plastic weighing almost 80,000 t are currently afloat in the Pacific garbage patch, which is regarded as the largest accumulation zone for plastics waste worldwide. This amount is up to sixteen times higher than previously reported. To analyse the full extent of the GPGP, an international team of more than 70 engineers, researchers and scientists working on the project crossed the debris field with 30 vessels simultaneously, supplemented by aerial surveys. Altogether, the fleet collected 1.2m plastic samples. Laurent LeBron, lead author of the study said “plastic pollution levels within the patch have been growing exponentially since measurements began in the 1970s.” A report by the International Union for Conservation of Nature (Gland / Switzerland; www.iucn.org) found that as much as 9.5m t of trash is deposited in the ocean every year.

Not least because of the enormity of the challenge, but also for reasons of ecology, not all are as convinced about the project’s merits as its initiator. Many ocean conservation organisations have said they believe it unlikely that the unwieldy device can make any kind of meaningful dent in the agglomeration of garbage. This especially in view of the slowness of many countries – for example, in Asia – to tackle the problem of littering. The Ellen MacArthur Foundation (Cowes / UK; www.ellenmacarthurfoundation.org) has predicted that there will be more plastic than fish in the oceans by 2050 unless drastic action is taken – see Plasteurope.com of 09.02.2016. Ocean Cleanup's founder and CEO Boyan Slat has countered critics by saying that both approaches are needed.

Among those who have questioned the concept, Bonnie Monteleone, executive director of the non-profit platform Plastic Ocean Project (www.plasticoceanproject.org), said she would rather see money invested in smaller-scale plastics collection efforts like “Mr. Trash Wheel”, a solar-powered vessel in the harbour of Baltimore, Maryland / USA. This scoops up plastic bags, bottles and other debris before they can break up and drift out to sea as microplastics. Waste Free Oceans (Brussels / Belgium; www.wastefreeoceans.org) is another organisation implementing a floating collection device, which is equipped onto fishing boats – see Plasteurope.com of 07.07.2017. Some marine biologists have said they fear that Ocean Cleanup’s equipment could harm fish and other marine life. The Dutch organisation, however, has stressed that the danger to sea creatures from entanglement or ingestion of plastics is far greater.

To avoid trapping or disturbing marine life, Slat’s team did not use nets in designing its apparatus but rather an impermeable “skirt” that hangs three metres below its floating buoys. As water cannot pass through the skirt, the current flows beneath it, allowing fish to easily slip below the floating collectors. Ocean Cleanup also hired a consultant to conduct an environmental impact assessment to address potential risks. Overall, the organisation said, “the conclusions indicate a low or negligible risk.” One “medium risk” found was the potential attraction of sea turtles to the vessel and chance that they could ingest plastic particles concentrated near the floating screen. No high impact risks were identified.