A plastic ocean

Over the past decades, ocean plastic pollution has become one of the most urgent global environmental challenges. Plastics continue to enter marine environments through a variety of pathways, accumulate and persist for long time periods in many different forms, from large items to microscopic fragments that are integrated into ecosystems and food chains.

Most of the plastic entering the ocean originates on land. Mismanaged waste, especially single-use plastics such as packaging, bottles, and bags, can be transported by wind, stormwater runoff, and river streams into coastal waters. Rivers have been identified as major routes, carrying waste from inland urban and rural areas to the sea, with studies suggesting that a small number of heavily polluted rivers contribute a disproportionate share of this waste. Marine sources also contribute to ocean plastic pollution, with fishing vessels and lost or discarded fishing gear, as well as shipping activities, offshore oil and gas operations, and tourism directly introducing waste into the marine environment.

Once in the ocean, plastics do not fully biodegrade, but they persist in our environment for longer than decades. When exposed to environmental factors, such as sunlight, waves, and temperature changes, large items undergo physical and chemical changes, breaking down into smaller pieces known as microplastics (plastic particles smaller than 5 mm). Microplastics can also enter the ocean directly as primary microplastics, found in some cosmetics, cleaning products, or industrial abrasives. These microplastics are now ubiquitous, found from surface waters to deep-sea sediments, and can be ingested by marine organisms at all trophic levels. 

Quantifying the amount of plastic entering the ocean every year can be quite challenging, but it has been estimated that roughly 8 -12 million metric tons enter the ocean annually, equivalent to dumping more than a garbage truck full of plastic into the sea every minute. Some studies suggest the figure could be even higher, reaching up to 14 million metric tons per year, emphasising that these numbers are rough approximations, and that the real amount of plastic entering the ocean may be much larger.

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For more information contact: info@scarabtrust.org.uk

Image: white and blue ocean waves - Photo by Matt Paul Catalano (ST ref: 1313)