The Menace of Marine Litter

Marine litter, long a neglected topic, has started to garner some attention. Marine litter is composed of a diverse mix of items from various sources and so a one-size fits all solution is unlikely to be effective. Abandoned, lost and discarded fishing gear (ALDFG), plastic packaging (bottles, caps, bags, etc.) and plastic manufacturing pellets are amongst the most common and persistent items found. Comparing the feasibility and the financial case for recovery versus prevention for each of these groups reveals a worrying gap in our attempts to deal with the problem.

Scale of the Problem

Abandoned, lost and discarded fishing gear (ALDFG) is arguably the most damaging type of marine debris as it continues to fish the oceans, trapping and killing animals for years after it goes overboard. Nets are often located in high numbers around known fishing grounds making targeted recovery possible. Even in such hotspots, recovery is costly and tends to fall to the third sector. An effectively priced deposit scheme with port and shore facilities to support the collection and recycling of damaged gear should reduce the amount of fishing gear discarded and fund the recovery of the remaining items.

While it is thought that 80% of marine litter originates on land, it seems clear that there is an on-going flux between terrestrial and marine environments. Floods can increase the flow of litter down rivers to the sea, while storms stir up the ocean, leading to litter that has already entered the marine environment being deposited in greater than usual amounts on beaches.

In 2013 the European Commission published three studies looking into the composition and sources of marine litter in European seas. In a chapter integrating the results it noted that:

“Plastics are the most abundant debris found in the marine environment and comprise more than half of marine litter in European Regional Seas. More than half of the plastic fraction is composed of plastic packaging waste with plastic bottles and bags being predominant types of plastic packaging…

Therefore, measures within a strategy to close the largest loopholes in the plastic packaging cycle should target plastic bottles and plastic bags.”

Capping the Problem

Plastic packaging is one of the most common items of marine debris with grave impacts upon marine wildlife. Foraging birds are known to ingest large quantities of plastic, especially caps and lids, turtles eat plastic bags mistaking them for jellyfish, and many species are recorded as trapped and disfigured by beverage can yokes.

However the impacts are even further reaching. As plastics break down they are ingested by smaller and smaller organisms. Recent studies have found that plankton ingest tiny fragments of plastic which are then passed up the food chain through predation. In fact, there may already be plastic in the tissue of the fish that we consume.

Despite hype about profitable schemes that will clean the ocean gyres in five years, the breakdown of material makes recovery almost impossible. Plastic debris may outweigh plankton by a ratio of 6:1 in the areas of highest concentration but widespread skimming of the ocean surface will also harvest vast amounts of the phytoplankton, zooplankton and other organisms living there. The majority of marine life lives at the surface and so, considering the risk of disruption to the entire marine food chain, the plankton baby is one that you really don’t want to throw out with the plastic-polluted bathwater.

Whilst debris recovery efforts may be able to remove small quantities of plastic packaging, in particular the larger items, it cannot deal with the full spectrum and so is largely ineffective as a response to the litter problem. The real challenge is not to clear litter once it is in the ocean doing damage, but to prevent it from getting there in the first place. Container deposit schemes and plastic bag levies have been shown to be highly effectual means of reducing litter on land; and by extension, will help to prevent marine litter.

Ex-Pellets from the Oceans

Plastic manufacturing pellets, or nurdles as they are known in the industry, are often underreported debris items as they are so small that they often escape observation. They are typically less than 5mm in diameter and unusually for marine debris are from known sources as they are only used in the manufacturing of plastic products.

Locating and separating such small objects from the world’s oceans is clearly a mammoth task of considerable expense. Instead the manufacturing industry has initiated a programme of environmental responsibility to limit the loss of the pellets. Praised as an effective and affordable program, the initiative would have even greater impact if adopted as an industry standard world-wide, especially if combined with further efforts to reduce pellet loss during transport.

There are no effective natural processes that remove marine debris. The flow of material into the oceans vastly exceeds any practicable man-made method of extracting this growing soup of litter. The only way to tackle the issue is to prevent litter entering the oceans in the first place. Effective measures to prevent this pollution at source already exist. Some, such as levies on single use carrier bags, are becoming more widespread, but others such as deposit refund schemes are still very limited, both in terms of geography and the types of packaging targeted. 

 

Note: The article is being republished with the kind permission of our collaborative partner Isonomia. The original article can be viewed at this link.

Republished by Blog Post Promoter

About George Cole

George Cole works for British waste and recycling specialists Eunomia Research & Consulting. His current work focuses on waste avoidance measures, environmental economics and evaluating ecosystem services. George holds a Master’s degree in Earth System Science and a Bachelor’s degree in Computer Science, which have led to his involvement in developing unique technological solutions to environmental issues.
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4 Responses to The Menace of Marine Litter

  1. Bill Thomas says:

    Mr. Cole, Your view that the best answer to ocean waste is “to prevent it from getting there in the first place” still leaves us with oceans full of plastic, worsening by the year. Thinking broadly into the future beyond what’s currently practicable, what do you see happening with these mountains of trash? Assuming it could be gathered at some point without major food chain damage, as you describe, some use would need to be found for it beyond just dumping it somewhere else or shooting it into space. Maybe that’s a stopgap solution. The current dumping is rising, not falling. How long before the oceans die? What’s our time frame? Bill Thomas, Kunming, China

    • George Cole says:

      Hi Bill. You’ve raised some good questions so let me tackle them one by one. I wholeheartedly agree that there is an unacceptable quantity of litter already in our oceans and that it must eventually be removed. The point you picked up on is simply that we need to stop adding more waste to our rivers and oceans so that we aren’t making the situation any worse, and so prioritise tackling the issue in the most effective manner.
      Plastic that is removed from the marine environment is often bio-fouled, which means that it needs careful cleaning before it can be recycled, and the plastic itself is often degraded making it difficult to recycle it into high quality products. These two factors make recycling marine plastics costly even if the material can be easily collected. It will therefore be difficult to find a market for recycling marine plastics. Projects that use marine litter in artwork, clothing, skateboards and other products to raise public awareness about the issue are a great use of what we pull from the sea. If we get to the point where we extract large quantities of marine litter then let this be a visual reminder to take proper care of our marine resources.
      I cannot say how long we have before our oceans die, but we should certainly be concerned about the harm caused by the marine litter already present and the litter that we continue to add to the marine environment. Certainly the time to act is now. The quicker we stop the flow of litter into the oceans the quicker we can prioritise removing what’s already out there. The policy measures I outline in the article would go a long way to achieving this aim.

      • Bill Thomas says:

        George, Thank you for your reply. Your blog certainly opened my eyes to the direness of the situation, namely that 1) it’s all different junk and it’s breaking up so it can’t just be picked up and recycled; 2) it’s killing the oceans by interfering with fish and plant life and oxygen availability; 3) removing it is itself a problem because it would take with it ocean nutrients; and 4) we’re continuing to dump waste and it’s not slowing or reversing anytime soon.

        It occurs to me that research into plastic-eating mealworms and caterpillars could be promising as long as they don’t introduce a new threat of invasive species. Could we dump the plastic into huge sealed containers (round, so they roll and don’t kill the ocean life) and dump trillions of worms inside? That’s my science fiction solution. Because Venice Beach can’t sell that much marine litter artwork.

        i look forward to your next installment.
        Thanks,
        Bill

  2. George Cole says:

    Hi Bill. You’ve raised some good questions so let me tackle them one by one. I wholeheartedly agree that there is an unacceptable quantity of litter already in our oceans and that it must eventually be removed. The point you picked up on is simply that we need to stop adding more waste to our rivers and oceans so that we aren’t making the situation any worse, and so that we are tackling the issue in the most effective manner.
    Plastic that is removed from the marine environment is often bio-fouled, which means that it needs careful cleaning before it can be recycled, and the plastic itself is often degraded making it difficult to recycle it into high quality products. These two factors make recycling marine plastics costly even if the material can be easily collected. It will therefore be difficult to find a market for recycling marine plastics. Projects that use marine litter in artwork, clothing, skateboards and other products to raise public awareness about the issue are a great use of what we pull from the sea. If we get to the point where we extract large quantities of marine litter then let this be a visual reminder to take proper care of our marine resources.
    I cannot say how long we have before our oceans die, but we should certainly be concerned about the harm caused by the marine litter already present and the litter that we continue to add to the marine environment. Certainly the time to act is now. The quicker we stop the flow of litter into the oceans the quicker we can prioritise removing what’s already out there. The policy measures I outline in the article would go a long way to achieving this aim.

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