Marine plastic pollution is a type of pollution caused by plastic items, which can be as large as bottles and bags or as small as tiny plastic pieces called microplastics and nanoplastics. Marine debris is mostly human-made waste that floats or is suspended in the ocean. About 80% of this waste is plastic. Microplastics and nanoplastics form when plastic waste breaks down in water, such as in oceans or rivers. Scientists have found nanoplastics in heavy snow, with about 3,000 tons falling on Switzerland each year.

It is estimated that there are 86 million tons of plastic waste in the world's oceans as of 2013. This number assumes that 1.4% of all plastic produced globally between 1950 and 2013 has entered the ocean. In 2022, about 300 million tons of plastic were used worldwide each year, with around 8 million tons ending up in the ocean as large plastic pieces. About 1.5 million tons of tiny plastic particles, called primary microplastics, also enter the ocean each year. Most of this waste comes from land-based activities, with the rest from activities at sea. It is estimated that 19 to 23 million tons of plastic enter aquatic ecosystems every year. A 2017 United Nations Ocean Conference report suggested that by 2050, the weight of plastic in the oceans might exceed the weight of all fish.

Oceans are polluted by plastic items of all sizes, from large objects like bottles and bags to tiny microplastics. These plastics break down very slowly and remain in the ocean for a long time. Plastic waste, such as bags, six-pack rings, and cigarette butts, harms wildlife and fisheries. Marine animals can be injured by becoming tangled in plastic, suffocating, or eating plastic. Fishing nets, often made of plastic, can be lost or abandoned in the ocean. These nets, called "ghost nets," trap animals like fish, dolphins, turtles, and seabirds, causing harm such as starvation, injury, and suffocation. Bottle caps have been found in the stomachs of sea turtles and seabirds, blocking their ability to eat or breathe. Ghost nets also trap marine life in a process called "ghost fishing."

The ten countries that release the most plastic into the ocean are China, Indonesia, Philippines, Vietnam, Sri Lanka, Thailand, Egypt, Malaysia, Nigeria, and Bangladesh. These countries contribute about 90% of all plastic that reaches the world's oceans, often through rivers like the Yangtze, Indus, Yellow River, Nile, and Ganges. Asia is the largest source of mismanaged plastic waste, with China alone responsible for 2.4 million metric tons of this waste. Reports show that China, Indonesia, Philippines, Thailand, and Vietnam together dump more plastic into the ocean than all other countries combined.

Plastics do not break down naturally like many other materials. They can be broken down by sunlight, but this process works best in dry conditions. Water slows this breakdown, and in the ocean, plastic breaks into smaller pieces while still holding its chemical structure. When plastic breaks down to the size of tiny ocean animals called zooplankton, jellyfish may eat them, allowing plastic to enter the ocean food chain.

Solutions to marine plastic pollution will involve changes in how products are made and used, especially reducing the use of single-use or short-lived plastic items. Ideas for cleaning up ocean plastic include capturing plastic at the mouths of rivers before it enters the ocean and cleaning up large areas of ocean called gyres.

Scope of the problem

Marine pollution from plastic is a serious problem. Many plastics used daily are not recycled. Single-use plastics contribute to about 8 million tons of plastic waste entering the ocean each year. If this continues, by 2050, there could be more plastic than fish in the ocean by weight. Between 2000 and 2010, more plastic was created than in all previous history combined, and most of it is not recycled. By 2015, the world had produced about 8,300 million metric tons of plastic, with 79% ending up in landfills or the environment. Recent estimates show that 14 million tons of plastic are now in the ocean. Scientists estimate there are between 15 and 51 trillion pieces of plastic in the world’s oceans, from the surface to the seafloor. Oceans are Earth’s deepest and largest areas, with average depths of about 4 kilometers. Gravity moves materials from land to the ocean, making the ocean a final place for waste. Plastic pollution is found everywhere in the ocean, including trenches, the seafloor, ridges, the surface, and coastal areas. Even remote islands have plastic from faraway places. Plastic waste gathers in large circular ocean currents called gyres. These gyres form because of wind patterns and ocean currents.

Plastics are made because they are flexible, strong, and can be shaped into many useful items. Plastics do not break down easily from natural weathering processes. Ocean conditions, like storms, waves, and sunlight, break plastic into smaller pieces called microplastics instead of fully breaking it down. Scientists estimate there are about 5.25 trillion plastic pieces in five major gyres, weighing nearly 300,000 tons. Microplastics settle in deep ocean sediments, with four times as much plastic found in sediments as on the ocean surface. Plastics now interact with living things, such as whales, birds, and bacteria, which may eat plastic.

Each year, over 300 million tons of plastic are made, with half used for single-use items like bags and packaging. About 19–23 million tons of plastic enter water ecosystems yearly. Scientists estimate there is about 150 million metric tons of plastic in the ocean. Plastic makes up 80% of all ocean debris, from the surface to the deep sea. Because plastic is light, much of it floats on the ocean surface, but it is now found in many places, including rivers, lakes, coral reefs, and deep-sea areas. Submarine canyons help move plastic to the deep ocean. The most visible signs of plastic pollution are large garbage patches in gyres. A gyre is a circular ocean current caused by wind and Earth’s rotation. Five main gyres exist: the North and South Pacific, North and South Atlantic, and the Indian Ocean gyres. Each has significant garbage patches.

Large plastic pieces (macroplastics) can be eaten by marine animals, making them feel full without getting nutrients. This can cause animals like seabirds, whales, and turtles to starve. Plastic waste can also trap or suffocate animals. Macroplastics break into smaller pieces called microplastics when exposed to sunlight, waves, or wind. Some tiny creatures, like amphipods, can chew through plastic, turning it into microscopic fragments. Even though plastic breaks into smaller pieces, it does not biodegrade. About 90% of plastic in the open ocean is microplastics. Some microplastics come from products like microbeads and nurdles. These are eaten by small sea creatures, like plankton and fish larvae, and move up the food chain. Plastics often contain harmful chemicals, which enter the food chain and may end up in fish that humans eat.

Types of sources and amounts

Plastic waste entering the oceans is increasing each year. Much of this waste is in tiny pieces smaller than 5 millimeters. In 2016, it was estimated that about 150 million metric tons of plastic pollution were in the world’s oceans. This number is expected to reach 250 million metric tons by 2025. Another study from 2012 estimated that about 165 million metric tons of plastic were in the oceans. In 2020, a study found that the Atlantic Ocean has about ten times more plastic than previously thought. The largest type of plastic pollution (about 10%) and most of the large plastic in the oceans comes from lost or discarded fishing nets.

The Ocean Conservancy reported that China, Indonesia, the Philippines, Thailand, and Vietnam together dump more plastic into the ocean than all other countries combined.

One study estimated that more than 5 trillion pieces of plastic (classified into small microplastics, large microplastics, meso- and macroplastics) are floating in the ocean. In 2020, new measurements found more than 10 times as much plastic in the Atlantic Ocean than previously estimated.

In October 2019, research showed that a significant amount of ocean plastic pollution comes from Chinese cargo ships. An Ocean Cleanup spokesperson said, “Everyone talks about saving the oceans by stopping the use of plastic bags, straws, and single-use packaging. That’s important, but when we go out on the ocean, that’s not necessarily what we find.”

Almost 20% of the plastic debris polluting ocean water, or about 5.6 million metric tons, comes from sources in the ocean itself. MARPOL, an international treaty, bans the disposal of plastics at sea. Merchant ships release cargo, sewage, used medical equipment, and other waste containing plastic into the ocean. In the United States, the Marine Plastic Pollution Research and Control Act of 1987 prohibits the discharge of plastics in the sea, including from naval vessels. Naval and research vessels throw away waste and equipment that are no longer needed. Pleasure craft release fishing gear and other waste, either accidentally or due to poor handling. The largest source of ocean-based plastic pollution is discarded fishing gear, such as traps and nets, which may make up to 90% of plastic debris in some areas.

Plastic litter from land enters the ocean mainly through stormwater runoff, which flows into rivers or directly into coastal waters. Plastic in the ocean follows ocean currents, which eventually form large areas of floating debris called Great Garbage Patches.

The impact of microplastics and macroplastics on the ocean is not directly from dumping plastic into marine ecosystems, but from polluted rivers that connect to the ocean. Rivers can act as sources or sinks of plastic pollution depending on the situation. Rivers are a major source of ocean plastic pollution, though they may not contribute as much as direct input from coastal populations.

The amount of plastic recorded in the ocean is much less than the amount entering the ocean at any given time. A study in the UK found that there are “ten top” types of macroplastic waste linked to consumer use. In this study, 192,213 litter items were counted, with 71% being plastic and 59% being consumer-related macroplastic items. Although freshwater pollution is a major contributor to marine plastic pollution, there is limited research and data collection on how much plastic moves from freshwater to marine environments. Most studies agree that there is little data on plastic debris in freshwater and natural land areas, even though these are major sources of pollution. Changes in policies related to plastic production, use, disposal, and waste management are needed to reduce plastic entering freshwater environments.

A 1994 study of the seabed in the northwestern Mediterranean near Spain, France, and Italy found an average of 1,935 debris items per square kilometer. Plastic debris made up 77% of this, with 93% being plastic bags.

About half of the plastic in the ocean floats on the surface. However, when organisms attach to plastic, it can sink to the ocean floor, where it may harm sea life and processes that exchange gases in sediment. Factors affecting microplastic buoyancy include the plastic’s density, size, and shape. Microplastics can also form a floating layer of biofilm on the ocean’s surface. Changes in buoyancy from microplastic ingestion have been observed in autotrophs, as the absorption can interfere with photosynthesis and gas levels. This issue is more significant for larger plastic debris.

Estimates of land-based plastic contributions to the ocean vary. One study estimated that over 80% of ocean plastic comes from land-based sources, contributing about 800,000 metric tons each year. In 2015, it was calculated that 275 million metric tons of plastic waste was generated in 192 coastal countries in 2010, with 4.8 to 12.7 million metric tons entering the ocean—about 5% of total waste.

Most land-based plastic pollution enters the ocean from South, Southeast, and East Asia, with major contributors including China, Indonesia, the Philippines, and India.

A growing concern is landfills, where much of the plastic waste is single-use items like packaging. Disposing of plastic in landfills leads to accumulation. While landfills produce fewer gas emissions than incineration, they face space limitations. Landfill liners, which protect the environment from waste, can break, leaking toxins into soil and water. Landfills near oceans often contribute to ocean debris, as waste is carried to the sea by wind or waterways like rivers and streams. Untreated sewage water and improperly discarded plastic items can also reach the ocean through stormwater.

Microplastics

A major issue in the marine ecosystem is the use of microplastics. Microplastics are tiny plastic pieces smaller than 5 millimeters. They are often found in hand soaps, face cleansers, and other exfoliating products. When these products are washed down the drain, the microplastics pass through water treatment systems and enter the ocean. Because they are so small, they often escape being caught by the screens used in wastewater plants. These tiny plastic pieces harm ocean life, especially filter feeders, which may swallow the plastic and become sick. Microplastics are hard to clean up because of their size, so people can help by choosing products that use safe, non-plastic exfoliants.

Plastic is used widely around the world, so microplastics are now common in the ocean. They can be found on beaches, in surface water, deep in the ocean, and even in ocean sediments. Microplastics are also mixed with other materials, such as dead plant or animal matter and soil particles carried by rivers. The number of microplastics in an area often depends on how many people live nearby and how close the area is to cities.

More microplastics are found in places where heavy rain occurs. Rainwater can carry plastic debris from land into waterways. The more rain there is, the more erosion happens, and the more plastic is washed into the ocean.

Microplastics enter waterways in many ways, such as from worn-out road paint, tire particles, city dust, spilled plastic pellets from shipping containers, abandoned fishing nets, synthetic textiles in laundry, and coatings on ships that break down over time.

Coatings on ships are a major source of microplastics. In the German Bight, nearly 80% of plastic pieces found were from ship coatings, not land sources. These coatings often use materials like polyvinyl chloride or poly(methyl methacrylate), while land-based plastics are usually made from polypropylene, polyethylene, or polyethylene terephthalate. Over time, ship coatings degrade due to weather and ocean waves. Compared to land-based plastics, ship coatings contain more chemical additives, such as adhesives, biocides, and pigments. These chemicals can harm marine life. For example, biocides like tributyltin (TBT) were found to cause health problems in sea snails in the 1980s. Today, some biocides are banned, but other coatings still release harmful chemicals. Regulations for ship coatings are limited, though some restrictions exist for specific chemicals.

Once in the ocean, microplastics move far because they are light and small. Their movement depends on their shape, water flow, and ocean conditions. Scientists use models to track how microplastics travel in the ocean.

Some microplastics leave the ocean and enter the air, as discovered in a 2020 study. Most plastic debris on the ocean surface is microplastic, according to a 2018 study. Some microplastics sink to the ocean floor. A 2020 study estimated that 14 million metric tons of microplastics are already on the ocean floor, up from earlier estimates of 93,000 to 236,000 metric tons in 2015 and 270,000 metric tons in 2018.

A study of plastic debris in the eastern Pacific Ocean showed that plastic concentrations increased tenfold between 1972–1985 and 2002–2012.

Microplastics in the Arctic Ocean mostly come from Europe and North America. Studies show that microplastics on glaciers and snow are more concentrated than in urban areas, even though no microplastics are made near glaciers. In 2021, Europe and Central Asia were responsible for about 16% of global microplastic pollution.

Higher microplastic levels on glaciers suggest that wind carries microplastics across long distances.

Microplastics can collect in ocean foam and may affect how waves break, potentially changing how the ocean interacts with the atmosphere. A study found that microplastics can be found in sea breezes and may return to the air.

Microplastics can build up in the gills and intestines of marine animals, harming their ability to eat and often leading to death. In some cases, microplastics cause fish, mussels, and tiny worms to stop swimming and eating. The size of microplastics and the structure of an organism’s body determine how much harm they cause.

When microplastics are eaten by one animal and then eaten by another, they move up the food chain, harming ecosystems and reducing biodiversity. If a predator eats an animal that has swallowed microplastics, the predator indirectly consumes the plastic. This process is called "trophic transfer." Whether microplastics are passed out of the body or stay inside depends on the animal’s diet and other factors.

Toxic chemicals

Toxic additives used in the production of plastic materials can seep into the environment when they come into contact with water. Approximately 8,000 to 19,000 tonnes of these additives are carried by floating plastic materials around the world, with a large amount reaching the Arctic. Water-based pollutants that do not mix with water can gather on the surface of plastic waste, making plastic more harmful in the ocean than on land. These pollutants can build up in the fatty tissues of animals and increase in concentration as they move up the food chain, harming top predators and humans. Some additives in plastics can interfere with the endocrine system when ingested, while others may weaken the immune system or reduce reproductive success.

Floating plastic waste can also absorb long-lasting pollutants from seawater, such as PCBs, DDT, and PAHs. Plastic debris can take in toxic chemicals from ocean pollution, which may poison animals that eat it. In addition to harm caused by ingestion, some of these chemicals affect brain cells in animals in a way similar to the hormone estradiol, leading to hormone imbalances in wildlife. A study found that when plastics break down, they release harmful chemicals like bisphenol A (BPA) and PS oligomer into water. These chemicals are believed to harm marine life. BPA is a widely used chemical in food packaging and can seep into food, leading to human exposure. As a substance that mimics hormones, BPA interferes with the endocrine system and is linked to increased body fat in rodents.

Scientists collected seawater samples from around the world and found that all samples contained polystyrene derivatives. Polystyrene is a type of plastic used in items like styrofoam and household products. Researchers then simulated how polystyrene breaks down in the open ocean. The results showed that polystyrene begins to break down at temperatures of 86°C or higher, forming harmful chemicals such as BPA (which can harm reproduction in animals), styrene monomer (a suspected cancer-causing substance), and styrene trimer (a byproduct of polystyrene).

Plasticizers in microplastics have been linked to abnormal growth and reproductive issues in various animal models due to hormone disruption. Microplastics are also thought to cause irritation in the digestive system, changes in gut bacteria, disruptions in energy and fat metabolism, and increased cell damage.

Organic pollutants, such as pesticides, can enter the bodies of organisms that consume microplastics, along with dangerous metals like lead and cadmium.

Accumulation sites

Plastic waste often collects in the center of large ocean currents called gyres. The North Pacific Gyre, for example, has gathered the Great Pacific Garbage Patch, which is now estimated to be one to twenty times the size of Texas (about 700,000 to 15,000,000 square kilometers). Scientists believe there may be as much plastic in the ocean as there are fish. This area has a very high amount of tiny plastic pieces floating in the top layer of the water. In samples collected from the North Pacific Gyre in 1999, the weight of plastic was six times greater than the weight of zooplankton (the main animal life in the area).

Midway Atoll, like all the Hawaiian Islands, receives large amounts of debris from the garbage patch. Ninety percent of this debris is plastic, and it builds up on the island’s beaches, creating a danger for the birds that live there.

A garbage patch is a group of floating plastic and other debris that forms because of ocean currents and human activities that increase plastic pollution. These human-made collections harm marine ecosystems, pollute oceans with harmful chemicals, and contribute to greenhouse gas emissions. Once in the water, marine debris can move easily. Floating objects may be carried by wind or ocean currents, often ending up in the center of ocean gyres where water movement is slowest.

Environmental impacts

Litter that enters the ocean is harmful to marine life and humans. Plastics in the ocean contain toxic substances, such as diethylhexyl phthalate, which can cause cancer, as well as lead, cadmium, and mercury. These harmful chemicals are absorbed by plankton, fish, and eventually humans through the food chain. Eating fish with these toxins can increase the risk of cancer, immune system problems, and birth defects. These chemicals are also found in everyday items like food, water, salt, toothpaste, and other seafood. In Indonesia, which is the second-largest source of plastic waste, studies found that 50% of fishermen had microplastics in their stools. Each sample contained between 3.33 and 13.99 micrograms of microplastic per gram of feces.

Most ocean litter is made of plastic, which remains in the environment for a long time and causes widespread pollution. In many countries, poor waste management allows plastic to enter water systems. As of 2016, there were 5.25 trillion plastic particles in the ocean, weighing about 270,000 tons. By 2021, the number of plastic particles had grown to between 15 and 51 trillion. Ocean currents carry plastic to large swirling areas called gyres, where it accumulates as pollution dumps.

Research on ocean plastic has grown rapidly. Between 2011 and 2019, studies on this topic increased from 46 to 853 publications worldwide. Scientists are concerned that some organisms have adapted to live on plastic debris, allowing them to spread to new areas and become invasive species. Marine animals can suffer injuries, infections, and difficulty swimming if they eat or get tangled in plastic. Floating plastic also helps invasive species spread, threatening ocean life and food chains. In 2014, researchers found bacteria in Australian waters breaking down plastic into pits and grooves, showing that plastic can degrade in the ocean. Studies also found microplastics in deep ocean sediments, though the cause of their presence is still unknown.

Plastic surfaces repel water, which helps bacteria form biofilms that support life. These biofilms encourage other organisms to grow. Researchers have studied how plastic breaks down in the surface layer of water. Unlike organic matter, which decomposes, plastic breaks into smaller pieces while staying a polymer. This process continues until the plastic becomes microscopic. Some plastics break down quickly, releasing harmful chemicals like bisphenol A and PCBs. As plastic breaks into tiny pieces, it accumulates in the ocean's upper layers. These small pieces are eaten by surface-dwelling organisms, entering the food chain. Plastic becomes so small it is hard to see, and it can release greenhouse gases when exposed to sunlight or water, worsening environmental harm.

Plastic particles in the open ocean break down from sunlight, becoming smaller over time. Eventually, these tiny pieces are eaten by microorganisms, which convert them into carbon dioxide. In some cases, microplastics are absorbed directly into microorganisms’ cells. Before this happens, many organisms may interact with the plastic.

Plastic pollution and climate change are connected. Toxins from breaking down plastics in the air speed up climate change. Making plastic requires fossil fuels, which release greenhouse gases. The ocean holds millions of pounds of plastic and contributes to climate change by emitting greenhouse gases as plastics break down. Burning plastic waste releases more toxins and black carbon into the air, which harms the ocean by polluting water and harming marine ecosystems.

Effects on animals

Plastic waste is found in all the world's oceans. This pollution harms about 100,000 sea turtles and marine mammals and 1,000,000 sea creatures each year. Larger plastics, called "macroplastics," such as plastic shopping bags can block the digestive tracts of larger animals when they are eaten. This can cause starvation by stopping food from moving properly or by filling the stomach and making the animal think it is full. Microplastics, which are tiny plastic pieces, harm smaller marine life. For example, plastic pieces in the center of ocean gyres outnumber live marine plankton, and these plastics move up the food chain to affect all marine life.

Fishing gear, such as nets, ropes, lines, and cages, often gets lost in the ocean and can travel long distances. This has harmed many marine animals, including coral. The gear is made of non-biodegradable plastic, and when coral becomes tangled in it, it can lose tissue and die.

Plastic pollution can poison animals, which can then harm human food supplies. Plastic pollution is considered highly harmful to large marine mammals, as described in the book Introduction to Marine Biology, which calls it the "single greatest threat" to them. Some marine species, like sea turtles, have been found with large amounts of plastic in their stomachs. When this happens, the plastic often blocks the digestive tract, causing the animal to starve. Sometimes marine mammals become entangled in plastic products, such as nets, which can harm or kill them.

Entanglement in plastic debris has caused the deaths of many marine organisms, including fish, seals, turtles, and birds. These animals get caught in the debris and may suffocate or drown. They also die from starvation or inability to escape predators. Being entangled often causes severe injuries, such as cuts and ulcers. At least 267 different animal species have been affected by entanglement or ingestion of plastic debris. Over 400,000 marine mammals are estimated to die each year from plastic pollution in oceans. Marine organisms can become trapped in discarded fishing equipment, like ghost nets. These nets are often made of synthetic materials, such as nylon, which makes them durable. If an animal grows larger while trapped, the plastic can cut into its body. Nets can also drag across the seabed, damaging coral reefs.

Some marine animals become tangled in larger pieces of garbage that cause harm similar to microplastics. Trash that wraps around an organism can cause strangulation or drowning. If the trash gets stuck around a non-vital ligament, the ligament may grow abnormally. Plastic in the ocean becomes part of a cycle because marine life that dies from it eventually breaks down in the ocean, releasing plastics back into the ecosystem.

Animals can become trapped in plastic nets and rings, which can lead to death. Plastic pollution affects at least 700 marine species, including sea turtles, seals, seabirds, fish, whales, and dolphins. Cetaceans, such as whales, have been seen in the Great Pacific Garbage Patch, where they face risks from entanglement and ingestion.

Many sea animals eat flotsam, or floating debris, by mistake because it looks like their natural prey. Plastic debris that is bulky or tangled can get stuck in the digestive tracts of these animals. For example, sea turtles often mistake plastic bags for jellyfish because the bags look similar when underwater. This can block their throat and lead to starvation or infection.

Many long-lasting plastic pieces end up in the stomachs of marine birds and animals, such as sea turtles and black-footed albatross. This blocks their digestive systems, reducing their appetite or causing starvation. In a 2008 Pacific Gyre voyage, researchers found that 35% of 672 fish caught had ingested plastic pieces.

As plastic levels in the ocean increase, more marine life faces risks from consuming plastic or becoming entangled. About 23% of aquatic mammals and 36% of seabirds have been affected by plastic in the ocean. Since up to 70% of ocean trash is on the ocean floor, and microplastics are only millimeters wide, nearly every level of the food chain is impacted. Animals that feed on the ocean floor may accidentally ingest microplastics while gathering food. Smaller marine life, like mussels and worms, sometimes mistake plastic for prey.

Larger animals are also affected because they eat fish that may have microplastics inside them. Humans can also consume microplastics by eating seafood, such as oysters and clams. Studies show that 36% of seabird species consume plastic, mistaking larger pieces for food. Plastic can block intestines and tear the lining of marine animals' stomachs, leading to starvation and death.

Some long-lasting plastics end up in the stomachs of marine animals. Plastic attracts seabirds and fish. When marine life eats plastic, it enters the food chain, causing problems when animals that have consumed plastic are eaten by predators.

Multiple studies have found plastics and microplastics in the stomachs of marine animals. Ingesting large amounts of plastic debris, like fish nets and ropes, can kill marine animals by blocking their stomachs.

A 2021 review in Science identified 1,288 marine species that ingest plastic. Most of these are fish.

Sea turtles are affected by plastic pollution. Some species eat jellyfish but often mistake plastic bags for their prey. Plastic debris can block their throat and kill them. Baby sea turtles are especially vulnerable, as shown by a 2018 study.

Various whale species, such as beaked whales, baleen whales, and sperm whales, ingest plastic. They may mistake plastic for food when feeding near it. Plastics can also enter their systems if their prey already has synthetic particles in their digestive tracts. Large amounts of plastic have been found in the stomachs of beached whales. Plastic debris has been in the stomachs of sperm whales since the 1970s and has caused the deaths of several whales. In 2018, more than 80 plastic bags were found inside a dying pilot whale in Thailand. In 2019, a dead Cuvier's beaked whale in the Philippines had 88 pounds of plastic in its stomach.

Effects on humans

Nanoplastics can enter the intestine of aquatic animals and may reach humans through breathing or eating, especially by consuming shellfish and crustaceans. Eating plastics has been linked to problems such as issues with reproduction, cancer, and changes in genetic material. A common chemical in many plastics is bisphenol A (BPA). BPA has been connected to autoimmune diseases and hormone-related problems, which can lower male fertility and increase the risk of breast cancer. Phthalate esters, found in food packaging materials, are also linked to reproductive issues because they affect the developing male reproductive system. Toxins from phthalate esters can harm the male reproductive system. Diethylhexyl phthalate may also affect thyroid function, but research on this is not yet certain.

Plastics inside the human body can slow or stop the body’s ability to remove harmful substances, leading to serious toxicity or death. They may harm the central nervous system and reproductive system, but this would likely only happen if exposure levels are very high and the body absorbs a large amount. Studies using human cells showed that polystyrene nanoparticles can be taken into cells and may cause increased production of harmful chemicals and inflammation.

Reduction efforts

Solutions to marine plastic pollution, along with plastic pollution in the whole environment, depend on changes in how products are made and packaged. This includes reducing the use of single-use or short-lived plastic items. Ideas for cleaning ocean plastic include trapping plastic at river mouths before it reaches the ocean and cleaning up large areas of plastic in ocean gyres.

Once microplastics enter the ocean, they are very hard and expensive to remove. These tiny plastic pieces can stay in the marine environment for a long time, possibly forever.

An organization called "The Ocean Cleanup" is trying to collect plastic from the ocean using nets. Some people are worried that this method might harm certain sea creatures, such as neuston, which live near the ocean's surface.

At TEDxDelft2012, Boyan Slat introduced an idea to remove large amounts of ocean plastic from gyres. His project, called "The Ocean Cleanup," uses ocean currents to guide plastic debris toward collection platforms. This method would cost less to operate and might even be profitable. Floating booms are used to guide, rather than trap, the plastic. This helps avoid harming other sea life while collecting even the smallest plastic pieces. Slat estimated that cleaning one gyre could take about five years and remove at least 7.25 million tons of plastic from all gyres. He also suggested using methods to stop plastic from entering gyres again. In 2015, the project won an award for design. A group of 30 ships, including a large mothership, traveled for a month to measure plastic levels using nets and aerial surveys.

Another organization, "everwave," uses special boats in rivers and estuaries to collect trash before it enters the ocean.

The Ocean Plastic Utilisation Ships System R&D project (OPUSS) aims to make ocean cleanup methods practical, environmentally friendly, and cost-effective. The project focuses on creating a new system for collecting and transporting ocean plastic, as current methods are not well-suited for ocean cleanup. The goal is to clean the ocean efficiently while keeping costs low.

The Clean Oceans Project (TCOP) works to turn plastic waste into useful liquid fuels like gasoline, diesel, and kerosene. This technology is developed by a Japanese company called Blest Co. Ltd. TCOP also plans to teach communities how to recycle plastic and keep shorelines clean by offering financial rewards.

In 2019, scientists from Washington State University discovered a way to convert plastic waste into jet fuel.

Another company, "Recycling Technologies," has developed a process to turn plastic waste into a type of oil called Plaxx. The company is led by engineers from the University of Warwick.

Other companies working on converting plastic waste into fuel include GRT Group and OMV.

Current international policies have some problems, such as focusing too much on pollution from the sea, using too many non-binding rules, and having many separate laws that do not work well together. To solve marine plastic pollution, four steps are important: making international laws consistent, ensuring national policies work together, coordinating international organizations, and improving communication between science and policy. These issues are driving efforts to create a global plastics treaty. This treaty is being developed and is expected to be completed by the end of 2024.

In the European Union, banning the use of microplastics in products like cosmetics, detergents, and paints could reduce microplastic emissions by about 400,000 tons over 20 years.

The trade of plastic waste from developed to developing countries is a major cause of ocean pollution because many countries lack the ability to process the waste. To address this, the United Nations banned the trade of plastic waste unless it meets specific standards. This ban started in January 2021.

History

Plastic pollution was first discovered in central gyres, which are large, rotating ocean currents. Observations from the Sargasso Sea were included in a 1972 journal article in Science. In 1986, a group of undergraduate students collected data by recording the amount of plastic they found on their ship while traveling across the Atlantic Ocean. Their research helped scientists gather long-term information about plastic in the Atlantic Ocean. This work also helped Charles Moore discover the Great Pacific Garbage Patch. The students’ research also contributed to the creation of the term "microplastics."

The term "microplastics" was first used by Richard Thompson in 2004. He described microplastics as small pieces of plastic, less than 5 mm in size, found in the ocean and other water bodies. After Thompson introduced the term, scientists began studying how microplastics affect the ocean.

The term "plastic soup" was first used by Charles J. Moore in 1997. He discovered patches of plastic pollution in the North Pacific Gyre, located between Hawaii and California. This area, now known as the Great Pacific Garbage Patch, was previously described in 1988 by scientists who used the term "neuston plastic." They defined it as the size of plastic debris caught in nets designed to collect surface plankton. Earlier studies from the 1970s showed that neuston plastic was widespread, especially in the central and western North Pacific, and moved by ocean currents and wind.

In 2006, Ken Weiss wrote an article in the Los Angeles Times that made the public aware of the Garbage Patch in the Pacific Ocean. In 2009, a group of researchers traveled to the Pacific Ocean to investigate whether the Great Pacific Garbage Patch was real or a myth. After several days at sea, they found hundreds of plastic pieces, which appeared as a "soup" of microplastics rather than large plastic items.

The term "plastic soup" is sometimes used to describe pollution caused by microplastics, such as tiny plastic fibers from synthetic clothing in laundry. In 2017, the British National Federation of Women’s Institutes passed a resolution titled "End Plastic Soup," focusing on this type of pollution.

The Plastic Soup Foundation, based in Amsterdam, is an organization that works to raise awareness about plastic pollution, teach people about the issue, and support solutions.

As of January 2019, the Oxford English Dictionary did not include the terms "plastic soup," "neuston plastic," or "neustonic plastic." However, it defined "microplastic" as "Extremely small pieces of plastic, made intentionally (such as nurdles or microbeads) or created when plastic products break down." The dictionary’s examples all relate to pollution in the ocean, with the earliest reference from a 1990 article in the South African Journal of Science.