Plastic pollution in Earth’s oceans
Scope of plastic problem[edit | edit source]
An estimated 311 million tons of plastic were produced in 2014, and the demand for plastic products is growing. By 2050, the world’s oceans may well contain more plastic than fish if current trends continue, as total production is expected to quadruple. Some 2050 estimates are even higher, including a 2000 million metric ton figure from United Nations. How much of that plastic already is in the ocean is difficult to ascertain, in part because so much of it is invisible, but a January 2016 report completed by World Economic Forum, McKinsey and the Ellen MacArthur Foundation estimates that the ratio of plastic to fish weight is currently 1:5. By mid-century, that’s projected to be a 1:1 ratio by weight – and the already devastating impact to marine life, human health, ecosystems and the environment will accelerate if not prevented. A total of 8 million metric tons currently ends up in the ocean each year.
Since the widespread use of plastics began in the 1950s, their applications have spread into nearly every corner of industry, including medicine, transportation, household goods, and above all packaging. Plastic packaging accounts for 26 percent of total use volume, which itself is now more than five times all of the plastic – just 15 million tons – produced in 1964. Plastic packaging has brought many benefits, but the reduction of plastic poisoning our land and sea includes an emphasis on the role of consumer choices.
The highly visible scenes of wildlife trapped in plastic rings, or the trash-strewn shores of once pristine coasts, often move people to action. That’s just part of the story: Plastic production is heavily dependent on fossil fuels, and forecasts suggest that the 6 percent of global oil consumption the industry accounted for in 2014 will become 20 percent by 2050, and that will be about one-sixth of world’s carbon budget.
Sources of plastic waste[edit | edit source]
Plastic, from a chemical standpoint, is any substance in a group of synthetic polymers characterized by repeating molecular chains that make their decomposition difficult or theoretically impossible. There are many different types of plastic – including new developments -- but four dominate the global market. They are polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP) and polyvinyl chloride (PVC), although a notable presence of polystyrenes (PS) and polyurethanes (PUR) are in common use.
Plastic grocery bags are made using PE, and there are up to 1 trillion used each year. PET is used in water bottles – the No. 3 item on the Top 10 list of items picked up during coastal cleanups – and an estimated 42.6 billion single-serve bottles are used annually just in the United States. Globally, PET has a better recycling rate than other plastics, but less than half is being recycled and its decomposition rate is measured in hundreds of years. There were 43,662 kilotons of PVC produced in 2015, much of it in the construction industry, but use in food packaging continues to grow. The polysterenes are common in plastic utensils, CD jewel cases, meat packaging trays and throw-away coffee cups and fast food boxes.
Microplastics, additives and environment[edit | edit source]
Microplastics and newer nanoplastics are tiny beads of polymer that are pervasive in global waters, ingested by marine life and humans alike, and have the microscopic potential to move into the cells of exposed organisms. The 2016 “Marine Plastics Debris & Microplastics” report of the United Nations Environmental Program lists the presence of small particles less than 5 millimeters that show alarming accumulation rates across the planet. They’re common in everything from toothpaste to 3D printing materials, and released from automobile tires on the road or mechanically washed synthetic fabrics.
Marine research in 2009 found up to 215 tiny particles per liter in waters off the Florida coast in the United States. Subtidal Sweden saw up to 332 particles per 100 ml in 2007, while in the Deep Sea Trench of the Northwest Pacific, the count swells as high 2,020 particles per square meter in a 2015 sample.
The UN report includes page after page of scientific studies, conducted from 1973 through 2015, that document the ingestion of microplastic particles in whales, seals, sea scallops, mussels, fish and other marine life, including 100 percent penetration in samples of small fish like anchovies and herring. The same microplastic problem exists for seabirds from Tahiti to Antarctica. On the Great Barrier Reef, scientists confirmed in 2015 that coral species eat microplastics that become trapped in their cells.
A 2015 study reported three possible toxic effects of the plastic particles in humans: plastic particles themselves, any release of pollutants adsorbed in the plastics, and the leaching of plastic additives.
While plastics are a contaminant in themselves, they also absorb heavy metals and other toxins that enter the ecosystem and food chain – ultimately reaching the fish and shellfish eaten by humans. Yet some of those potentially toxic exposures come in the form of additives in plastic manufacturing. Among them is bisphenol A (BPA), a PVC additive that may be implicated in negative effects on human health.
Those additives also may include PBDEs, according to a December 2016 study from the U.S. Environmental Protection Agency. These flame retardants often added to plastics are known to be potential carcinogens, neurotoxins, and endocrine disruptors to both humans and exposed wildlife.
Scientists estimate there are more than 5 trillion particles in the global seas, and also are looking at the potential role of plastic in the oceans’ ability to absorb carbon dioxide and other climate connections. Those connections loop the plastic problem back to the big picture in terms of trash-strewn shorelines, destroyed habitats and ecosystems, social and cultural dimensions, and the economic impact to fishing livelihoods or tourism industries. It all points back to land-based waste practices as the real culprit.
Interventions and solutions[edit | edit source]
Recent evaluations of acute plastic pollution in the Arctic Ocean – where little of it is generated – underscore the need to stem the tide of plastic contamination at its source. As yet, there are no good answers for what to do with the plastic that’s in the ocean, although innovators work on underwater barriers and other solutions. One promising development is a new recycling method that will turn plastics back into oil. It’s under research at Recycling Technologies in the UK and may reduce the 90 percent of all plastics that end up burned into the air, or piling up in the world’s landfills and oceans.
Ultimately, experts see the solution in sustainable living and lifestyle choices. The Clean Seas group suggests that people’s individual decisions can drive change, like bringing one’s own reusable coffee mug to reduce the 4 billion plastic takeaway coffee lids that cannot be recycled and won’t decompose. Those decisions are powerful at the collective level to drive policy, when demanding bans on plastic bags in retail or improved recycling from municipal waste management systems. Choosing not to litter or participating in river or coastal cleanups also helps to keep plastic from ever reaching the ocean.