Micro-plastic ‘soup’: the oceans’ hidden threat
The micro-plastic ‘soup’ forming in the world’s oceans will have long term affects on the plants and animals living in them, warn experts.
While many people will now be familiar with the ‘Great Pacific Garbage Patch’ – one of the world’s largest landfills – floating in the middle of the Pacific Ocean, in reality similar patches are being discovered and monitored across the oceans.
“The focus has always been the Pacific Garbage Patch but in reality we see similar garbage patches in the Atlantic, in the South Pacific, the South Atlantic and so one,” Dr Simon Boxall, from the National Oceanography Centre at University of Southampton told RTCC. “The ‘Garbage Patch’ is not unique to the Pacific.
2006 estimates from the United Nations Environment Program suggest that every square mile of ocean hosts 46,000 pieces of floating plastic.
Discovered in 1997 by Captain Charles Moore, the Pacific Garbage Patch is made up of the Western Patch forming east of Japan and west of Hawaii and Eastern Patch floating between Hawaii and California.
The patches contain everything from fishing nets and plastic bottles and caps to toothbrushes, containers and boxes. But Dr Boxall warns against getting swept up in the image of a mass of rubbish you can see and touch.
“There has been a popular press for this mass of plastic bags and bottles and cans and things which pile up in the middle of the Pacific. The reality is that if you went out there you would be hard pushed to see much with the naked eye,” he explained.
“Most of the plastic in the ocean is actually very small, microscopic – we are talking about stuff that is maybe a centimetre, maybe a millimetre, maybe even a few microns across.”
Formation of the garbage patches
According to UNESCO global production of plastics increased at an average of 9% per year rising from 1.5 million tonnes in 1950 to 245 million tonnes by 2008. Following a drop in 2009 the rate of plastic is once again picking up.
When plastic is thrown away – not including that which is thrown directly into the ocean from the beach or boats – it has traditionally ended up in landfill, where much of it is buried. However, large quantities of it end up in the water-table and slowly make their way to the oceans.
Across the world’s oceans, gyres (large systems of rotating currents), pull the waste into the middle of the currents creating floating rubbish dumps.
Impacts and solutions
While larger discarded waste can cause entanglement, asphyxiation or blockage of organs in a variety of marine species including whales, seals, seabirds and fish, micro-plastics present a more insidious threat.
Dr Boxall said increasing research suggests that microscopic particles of plastic mimic materials including oestrogen and can have long term effects of the reproductive cycles and health of plants and animals in the ocean.
Plastics are also well known to accumulate persistent toxic chemicals.
As these smaller micro-chemicals are ingested more frequently than some of the larger waste, scientists worry that contamination could be transferred to marine life following digestion.
Research is yet to suggest, however, that mirco-plastic content in the oceans could have a direct effect on humans.
Dr Boxall said: “It is not questions of saying oh gosh we can never go in the sea again because of the amount of plastic. We do need to monitor it. We do need to keep an eye on it. The main problems are that we can’t do much about it.”
Once in the sea, these plastics can be near impossible to remove. Writing in UNESCO’s International Oceanography Commission 2011 annual report, Dr Tim Bowmer, chair of Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection wrote:
“Better waste management which includes far improved plastics recovery and recycling is obviously a major factor in preventing waste plastic reaching the sea.
“If Germany, Switzerland and Scandinavia can achieve really high levels of over 80% plastic recovery, then why not the rest of Europe, the USA and Japan as a starting point?”
Current trends do point towards equilibrium between the amount of plastic being put into the ocean and is found in the ocean gyres, and that which is going into the wider ocean or into sediments in the sea. While we have not stopped putting plastic into the ocean , we are no longer increasing it.
Boxall believes that as the price of oil rises, it becomes more economically viable to recycle and keep plastics in the system.
“So many more components of the plastics industry are actively supporting recycling and that is a good thing because it is keeping plastics in use rather than sitting in landfill or in the ocean,” he said.