Listen to discussion on the plastic problem in our seas on Today with Sean O’Rourke RTE Radio 1 (broadcast, 8th March ’16)
Plastic is all around us, in our clothes, glasses, computers, phones, toys and the packaging for food and drink products. Behind most election posters we looked at recently, there were strong plastic cables, holding those posters in place.
Plastic is lightweight, flexible, clear, opaque, almost unbreakable, and cheap to manufacture. It is a wondrous modern product, but it also has a dark side.
In Ireland we are producing in the region of 210,000 tonnes of plastic per year. Yet, we only recycle 36 per cent this plastic waste. That means that more than 100,000 tonnes of plastic here each year ends up buried in landfill sites, where experts say it could take 1,000 years to breakdown, or it finds it way to the sea.
Scientists in Ireland, and elsewhere, have grown concerned about a ‘steady stream’ of plastics entering our oceans and how that is affecting marine life. The evidence now emerging suggests that plastics are disrupting the balance of marine life to such an extent that it presents a real threat to all life on Earth.
About 45% of plastic waste is sent for burning, or waste-to-energy, as some would call it, while 15% or 30,000 tons is sent to landfill each year. The new Dublin ‘Waste-to-Energy’ plant due to open at Poolbeg in 2017, operated by Covanta, may help if it takes plastic waste that currently ends up put into domestic black bins – about 20% of all plastic waste.
Currently municipal solid waste, including plastic waste is sent for burning to European incinerators. Dealing with the plastic here, is in line with the proximity principle – that waste be dealt with as close to source as possible. It will also create jobs.
However, Repak are keen to say to people that they want more plastics put in the recycling, green bin, and not in the black bin, as some still do.
The amount of plastic waste is growing year on year by about 4% so this is not a problem that will be going away. The dumping of plastic waste is a big problem, according to a spokesperson for Repak (Ireland’s only industry-funded packaging recycling firm) with 80% of marine litter being plastic.
Repak that they are seeing less newspapers these days, and more cardboard (as a result of Internet shopping) and more plastic.
It is relatively easy to sort plastic bottles, he said, as they use optical sorters, which spot a bottle on a conveyor line and an air nozzle shoots the bottle off.
Interestingly, he said that some of the worst plastic packaging they have to deal with are rasher packs as they are made from a number of different plastic laminates and are very hard to break down.
This difficult mixed plastic is, however, useful as a ‘solid recovered fuel’ which is used as a replacement for coal in cement kilns.
All of the cement kilns in Ireland use this SRF and this is helping to reduce the amount of coal which we have to import – so plastic is not all bad,
Plastics products have been ubiquitous since around 1939, as during WW11 plastics production increased to replace scarce natural materials such as rubber.
But, it wasn’t until 1972, when scientists, by accident, that plastic waste was becoming a huge problem in our oceans.
A group of marine researchers were on a vessel in the Sargasso Sea, in the North Atlantic Ocean, trawling the surface of the ocean to collect a brown algae seaweed called Sargussum why they were interested in studying.
When they hauled in their first catch, they fund lots of tiny plastic particles. Further tows brought in further ‘catches’ of plastic. The finding of plastics in such numbers in the centre of the Ocean was a surprise and a concern.
Now, scientists estimate that there is more than 268,000 tons of plastic in the world’s oceans, some collecting, due to currents, in huge agglomerations of rubbish, and plastic with nicknames like the Great Pacific Garbage Patch (GPGP).
In parts of the GPGP there are 2 million pieces of plastic per square mile of ocean. But, as well as what are called macro-plastics, which can end up inside fish and marine creatures, blocking intestines, there are micro-plastics, which are much smaller, sometimes tiny piece of plastic, which are problematic too.
There are other garbage patches too, one off California, one close to Japan.
Plastic waste can enter the sea from cities and towns on the coastline, but it can also travel along inland waterways from places far from the coastline.
A recent study in the United States, published in the top journal Science, showed how far plastic can travel to end up in the ocean The ocean is always downstream of illegal dumping sites, where rubbish, including plastics, first ends up in rivers, streams and lakes. That’s true in the US, and in Ireland too.
There is clearly a plastic problem in Irish rivers. For example, the River Liffey at the Strawberry Beds outside Dublin. When the river Liffey is low, plastic bags can be seen hanging like vegetation out of trees normally submerged in the water. This plastic will end up, like the Liffey’s waters, entering the Irish Sea.
The extent of the problem of plastic in rivers in developed countries can be judged from the few cities, like Los Angeles and Baltimore, where there are engineering measures in place to prevent waste, including plastic waste, from entering the sea.
In 2015, Baltimore caught 118,670 plastic bottles alone which were prevented from entering the sea, as they would otherwise have done. Baltimore, by the way, has about twice the population of Dublin. If we assume that Baltimore and Dublin are pretty similar economically, then there are more than 50,000 plastic bottles – conservative estimate – entering the sea at Dublin each year.
Particularly damaging are micro-plastics; tiny pieces of plastic, which form when plastics are exposed to sunlight. micro-plastics are consumed by marine river life and then, when they make their way to the sea, by ocean creatures too.
Other research has shown that rivers and lakes in the US are full of tiny fibres of polyester and nylon, which are shed from clothes when they are laundered. The fibres are so small, they wash down drains into sewers and pass through the filtration system of wastewater plants, and end up out in the oceans too.
The fibres are swallowed by fish, and become lodged in their bodies, along with any bacteria or chemicals which may have been attached to the fibres in transit.
Ocean currents can transport plastic huge distances and computer models have shown that some plastics can travel more than 1,000 km in 60 days. So a piece of plastic could enter the sea in Dublin at the start of April, and end up floating off the coast of Lisbon by the end of May. It’s an international problem.
Marine life can mistake the larger plastic pieces for food, and plastics can thus get caught in their intestines. The fish or birds can’t get the plastic out of their bodies, and this hampers their ability to consume nutritional foods they need. They can ultimately end up starving to death. This has been reported in seabirds, turtles, fish and marine mammals.
When plastic pieces are smaller than 5 mm they are called micro-plastics. Micro-plastics act as an attractive solid surface for marine microbes, because nutrients, which the microbes need tend to accumulate on flat surfaces.
Marine creatures consume the micro-plastics, and the level of plastics then enters the marine food chain from the bottom up. There is on definite view on where this might end up, but certainly there are some very bad scenarios.
Amy Lusher, formerly a researcher at NUI Galway, and Simon Berrow, Chief Scientific Officer of the Irish Whale and Dolphin Group have carried out pioneering research in the problem of plastics at sea.
In May 2013, the two researchers were alerted when three beaked whales were found stranded on the north and west coast of Ireland. These creatures feed on squid in deep waters and little is known about them. They are rare, and it is highly unusual for three to be stranded within a few days and weeks of each other as happened here
An adult female was stranded at Five Fingers Strand in Donegal and two days later a whale calf was found washed ashore about 2km away. Then two weeks later, a second adult female beaked whale was found stranded at Ballyconneely in Co Galway. The immediate questions were why?
Post mortem results found that the two adult females had macro-plastics in their stomachs, while micro-plastics were identified throughout the digestive tract of the single whale that was examined for micro-plastics.
Simon Berrow told me in an email that it was “very disturbing” that micro-plastics were found throughout the digestive tract of the one beaked whale which was examined for micro-plastics, as these whales are offshore, deep-diving species which are very rarely even sighted by humans.
This was the first study, he said, that had directly identified micro-plastics, using a new technology, in the body of a cetacean species. Cetaceans are a group of 88 different species of whale, dolphin and porpoise. It suggests that even marine animals at the top of the food chain, feeding in deep waters, are ingesting significant amounts of micro-plastics into their bodies.
Simon is preparing a new research paper on the levels of micro and macro plastics in a range of dolphin species sampled in Irish waters over the last few years, and it will be interested to see if a similar result is confirmed again.
There can be many reasons why a marine creature gets stranded, or washed up on a beach. For example, there has been an increase in the number of dead dolphins washing up on the west coast of Ireland since the start of 2016, with 28 animals stranded, the second highest number every recorded for the first two months of the year.
Most of the strandings, scientists say, were in Mayo, Sligo and Donegal and the evidence showed that the dolphins died when they were caught up in the large fishing nets of foreign registered super-trawlers fishing in Irish waters.
Dolphins and other cetaceans (whales and porpoises) are under pressure in Irish waters from the nest of super-trawlers, as well as depletion of their natural prey – fish – due to over-fishing by the same trawlers. Add to that, the issue of micro-plastics and it’s no surprise to note that dolphin numbers are declining.
It will require a systematic, international response, from governments around the world, but, getting that, is always difficult.
It has been left to individuals to try and do something. For example, Boyan Slat, a Dutch guy in his early twenties, got a lot of publicity in 2013 for coming up with a plan to clean up the ocean using a V-shaped array of floating barriers.
The array was designed in such a way that the plastic pieces concentrated in the centre of the V, where they were then scooped up by a conveyor belt driven by solar panels and dropped in a collecting station for recycling. A modification of this approach will be used off the coast of Japan later this year.
Boyan’s efforts largely went unnoticed until he gave a TEDx talk, called How the Oceans can Clean Themselves’ and this went viral.
Individuals can also help by signing up to an app called Marine Debris Tracker. This involves people on the beach logging litter finds, which is fed into a database which can better help scientists study ocean rubbish patterns.
Barrack Obama signed legislation in December last to ban the use of plastic micro-beads in cosmetics. Micro-beads are used as exfoliating agents, and in toothpaste. They are made from petrochemical plastics like polyethylene, and they are so small that they pass through waste water treatment plants.
The micro-beads remain in the environment for 50 years, and are causing a build up of micro-plastic pollution in places such as Lake Erie in the USA.
The Plastisphere is the term that scientists use to describe how organisms have adapted in the oceans and elsewhere to live in harmony with human-made plastics.
Microbes are naturally attracted to plastics, which provide a solid surface to cling to in open ocean, and an all day buffet, as nutrients collect there too.
Some of the microbes ingest plastic too, and these plastic-loaded microbes are in turn eaten by plankton, which are tiny floating living organisms, which are in turn eaten by larger creatures such as fish and whales.
The reasons that scientists are concerned is that they have no idea how the presence of plastics in the marine food chain will play out into the future.
There is a concern, for example, that this could make global warming worse. Normally, in pre-plastisphere days, the oceans were a ‘carbon sink’ which absorbed excess carbon which could otherwise causing global warming.
This happened because tiny marine plants absorbed carbon dioxide, they were eaten by fish and other creatures, who pooped, and this poop, with carbon in it, fell safely to the bottom of the ocean.
The evidence now shows that plastic in poop causes it to break up easier, and this liberates carbon before it falls to the bottom of the ocean. So there is more carbon available to contribute to global warming.
There is also concern that plastics may be carrying harmful organisms, such as the carol pathogen reported in Hawaii and the Caribbean in 2014.
The worry is that plastics could transport some kind of microbe superbug across the world by travelling via ocean currents. The plastisphere offers microbes the chance to eat well and travel the world, even if they are dangerous pathogens.
The suspicion has to be that while micro-plastics have not been proven by scientists to have detrimental effects on marine life, that is what’s happening.
By the time the definitive proof is available, we may have already done irreparable damage to our oceans, as once something enters the food chain, as micro-plastics have done, it is going to be very difficult to remove it.
Scientists are loath to say seafood is not safe, and it is an important source of protein, as well as Omega 3. It’s know that plastics also attract chemicals, some very nasty ones like mercury, which can end up in the food chain.
The consensus is that the risk from plastics, and the chemicals they attract is still low in fish generally and not enough to outweigh the benefits from eating fish But, if we continue the way we are going, that consensus could change.
You must be logged in to post a comment.