Plastics are everywhere around us - in our homes, our vehicles, our computers, as packaging. They replace more traditional materials such as wood, metal, glass, leather, paper and rubber because they are lighter, stronger, more durable and corrosion resistant, and often cheaper.
But that durability means that most plastics do not biodegrade, so almost all the plastic ever produced is still here somewhere on the planet in one form or another, and will remain here for centuries to come, possibly thousands of years - nobody knows for certain yet.
According to a report by the Ellen MacArthur Foundation plastics production has increased twenty-fold since 1964, reaching 311 million tonnes in 2014, and is predicted to triple to 1124 million tonnes by 2050.
The report says that every year at least 8 million tonnes of plastic ends up in the ocean - equivalent to dumping the contents of one garbage truck into the ocean every minute. If no action is taken, this is expected to increase to the equivalent of two per minute by 2030 and four per minute by 2050.
It's estimated that there are already over 150 million tonnes of plastic waste in the oceans. This waste doesn't decompose, so the total amount cumulates over time. In a business-as-usual scenario, the ocean is expected to contain one tonne of plastic for every three tonnes of fish by 2025. There will be more plastic than fish in the ocean by weight by 2050.
A report by Eunomia says that over 80% of this plastic waste comes from land-based sources, mainly litter. The remainder is released at sea, mostly from fishing activities. 94% eventually sinks to the ocean floor. Some forms massive islands of waste such as the 'Great Pacific Garbage Patch'. The plastic can float around for decades before breaking down into smaller particles and becoming absorbed into the food chain or sinking and becoming part of the ocean floor sediment.
Health risks
Quite rightly, much attention has been focused on the dangers of plastic litter to seabirds, whales, dolphins, turtles, seals and other marine life. It's thought to cause the deaths of over a million seabirds and more than 100,000 marine mammals each year. Researchers are now warning that the risk of hidden contamination could be even more serious.
Unlike biological materials, plastic doesn't decompose. Instead, it photodegrades when exposed to sunlight, fragmenting into smaller and smaller pieces without chemically breaking down. But, no matter how small they become, these plastic bits never become digestible by any living creature.
In addition they contain additives such as pigments and plasticisers, known to be endocrine disruptors, plus toxic metals such as cadmium and lead. Research by the University of Plymouth has shown that the particles also attract toxic chemicals from the surrounding seawater and concentrate them on the surface of the plastic, acting as 'magnets' for poisons in the oceans.
These small poisonous particles, found throughout the oceans and mixed with the sand on beaches, are now threatening the entire food chain. The toxins they contain are known to be a threat to human health. In the water the particles are mixed in with and resemble the plankton, and are being mistaken for food and eaten by marine creatures and birds.
The process of bio-accumulation has the potential to further increase the concentrations of toxins as they pass along the food chain and into our human diets.
More information:
Plastic Pollution Coalition a global alliance working toward a world free of plastic pollution.
Plastics in the marine environment A report by Eunomia looking at where plastics come from and where they go.
International Marine Litter Research Unit University of Plymouth
Plastic Ocean An adaptation by the United Nations from the original documentary “A Plastic Ocean” by the Plastic Oceans Foundation.
The New Plastics Economy: Rethinking the future of plastics Report by the Ellen MacArthur Foundation and the World Economic Forum.
see also Microfiber pollution