Plastic pollution

The durable nature of synthetic plastic means that it may last indefinitely in the natural environment, where it is recognized as a form of pollution. A giant swirling mass of plastic has been found in the Pacific Ocean, for example. Scientists have even discovered a new kind of rock that contains plastic. Plastic is also increasingly found inside fish and birds, many of which often eat plastic fragments, and even inside humans at a microscopic level. Concerns about the amount of plastic polluting the environment have led researchers to focus on developing more natural plastics that are biodegradable.

Background

The group of materials known as plastics was developed during the nineteenth century. They have since become commonplace in consumer goods, including many popular forms derived from fossil fuels. Billions of tons of plastic have been produced since the 1950s, when the material began to rapidly gain in popularity.

All plastics are polymers, which are multiple molecules linked together to form long chains. Plastic polymers are mostly made of carbon. The long chains make plastics moldable because they can slip past one another. Some plastics are naturally derived, while others are completely synthetic.

The basis of most early manufactured plastics invented during the 1800s was cellulose, which is found in wood. The first fully synthetic plastic was Bakelite, which was invented in 1907. It was made from fossil fuels, as were many later types of plastic. During World War II, production increased and plastic was used to make military vehicles and equipment, such as insulation for radar equipment and airplane windows. When the war ended, plastic producers began making more consumer goods, such as food storage containers. Over the decades scientists developed hundreds of thousands of polymers, with common examples including polystyrene, polyester, polyvinyl chloride (PVC), polythene, and polyethylene terephthalate (PET).

The abundance of plastic products resulted in a great deal of plastic deposited into landfills. Many communities developed programs to recycle plastic, but many plastic products remained unrecycled. Efforts were also made to cut down on the demand for plastic goods, especially disposable ones. Plastic shopping bags, which largely replaced paper grocery bags in many stores, became one highly visible subject of debate over plastic pollution. Many people realized that using petroleum-based plastic bags was bad for the environment, both because using fossil fuels contributes to climate change and because the bags were often difficult to recycle and would last many years in nature, posing threats to wildlife.

Many consumers and environmentalists especially expressed concern about plastic ending up in waterways. Researchers have found plastic in the stomachs of many marine creatures; in the 2010s, studies found that half of the world's sea turtles and 90 percent of seabirds had eaten plastic. Many turtles died because plastic became lodged in their intestines, or starved to death because their stomachs were full of plastic. Plastic six-pack rings have been known to strangle birds and small animals that become entrapped in them. In 2020, the Pew Charitable Trusts reported that approximately 11 million metric tons of plastic entered the oceans every year, and warned that that figure would likely increase sharply if anti-pollution action was not taken.

To address public concerns about pollution, manufacturers developed biodegradable plastics. Some of these are indeed completely biodegradable, meaning they break down into harmless compounds over time. However, others are simply plastic beads mixed with biodegradable elements such as cornstarch—when these plastics break down, the tiny plastic particles are left behind. While such microplastics may not cause direct, visible threats such as strangulation, evidence began to grow that they nevertheless have considerable negative environmental impact. They may interfere with organisms' physiology after being ingested on a large scale.

Overview

Research has found that plastic pollutes every place on Earth. This debris includes everything from relatively large pieces—such as lumps of polystyrene foam, plastic bags, and water bottles—to smaller objects and fragments, to microscopic particles. Plastic pollution is embedded in sea ice and drifts to the deepest ocean depths.

Plastic has also been found in unexpected forms. For example, researchers discovered rocks containing plastic on the island of Hawaii, which they called plastiglomerates. The plastic fused to the natural materials was often clearly identifiable as parts of toothbrushes or forks. Scientists believed that the rocks originated on land, when people camping or fishing lit fires in which plastic melted. Natural fires such as forest fires or lava flow can also melt plastic trash, which could clump together with other materials to form rocks. The researchers who discovered plastiglomerates speculated that the rocks were probably all over the world, especially in places that burn trash, but had not yet been noticed. Many scientists believed plastics would be preserved in the fossil records of modern history, while others speculated that the intense pressure that creates fossils might slowly transform many plastics to carbon or oil.

An enormous, swirling garbage patch was discovered in the North Pacific Ocean in 1997. The Great Pacific Garbage Patch, also called the Pacific Trash Vortex, is made up of the Western Garbage Patch near Japan and the Eastern Garbage Patch between Hawaii and California. It is mostly plastic, much of which washed into the ocean from streams and rivers. About 80 percent is believed to come from North America and Asia. Other debris comes from boaters, oil rigs, and cargo ships that lost shipments during rough weather, notably including discarded fishing nets, known as ghost nets.

While other debris in the ocean decomposes, the plastic continues to swirl and pile up as more washes into the water. The sun breaks down the plastics into smaller pieces, in a process called photodegredation. This creates microscopic pieces known as microplastics, which some researchers have suggested make up a significant portion of the Great Pacific Garbage Patch; one study found estimated about 1.9 million bits of microplastic in one square mile of the patch. To the naked eye, microplastics may be invisible or barely cloud the water. Yet this layer can prevent sunlight from reaching plankton and algae, which are important in the marine food web. If fish and turtles that eat plankton and algae have less food, the rest of the food web is affected. Researchers have speculated that this could contribute to seafood shortages for humans as well.

Photodegradation also releases pollutants—chemicals and colorants—from the plastics. Microplastics can further absorb pollutants in the water. When marine life ingests the plastic, it also consumes these pollutants, which can build up in a process known as bioaccumulation. Eventually it can enter the human food supply.

In early 2018, scientists who had been collecting samples in the Arctic Ocean in 2014 and 2015 reported that they had discovered a record-breaking high amount of microplastics frozen into the sea ice. It was suspected that these plastics had drifted from other bodies of water, particularly the Pacific Ocean, over several years and had collected even more as more of the sea ice melted due to the effects of climate change; this increased melting was also leading to greater amounts of shipping and fishing in the area, which also results in plastics deposits. This observation caused further concern over the extent to which plastic pollution has spread over the entire world.

Although it is considered nearly impossible to completely remove microplastics from the ocean, many groups are working to keep the garbage patch from getting any larger. Some jurisdictions have passed regulations aimed at reducing the amount or types of plastics that are released into the environment. One example involves microbeads, tiny plastic balls added to many cosmetic products—usually as an abrasive agent in facial scrubs and toothpastes—that are too small to be filtered out by water treatment plants and end up in rivers and oceans. Microbeads have been found in many aquatic creatures. Under pressure from consumers, a number of companies began phasing out microbeads. In 2018, the UK government announced that manufacturers were prohibited from creating products that use microbeads. In 2019, about 180 nations agreed to an addition to the Basel Convention environmental accord, creating stricter rules regarding the export of plastic waste.

Researchers have also worked to develop new plastics using more natural materials. Sugar cane, for example, has been used to make bioplastic PET bottles. Products made with natural plastics can break down through microbial action.

Single-Use Plastics

One of the biggest areas of concern regarding plastic pollution is that of the dependence on single-use plastics, which are products such as packaging, straws, water bottles, and bags that are designed typically to be used once and then disposed of or recycled. According to the nonprofit Plastic Oceans, of the millions of tons of plastic produced annually, about 50 percent is meant for single use. Such single-use plastics are often the types of plastic that are thrown away rather than recycled or consist of plastics that are not recyclable. According to a 2018 report by the United Nations Environment Programme, as of 2015, only 9 percent of plastic waste ever produced had been recycled.

Consumer concerns have driven many changes. Environmentally conscious shoppers have turned to reusable shopping bags. In some cities in the United States, single-use plastic bag bans have been instituted. In March 2019, the European Parliament approved a measure to ban a number of single-use plastics, such as straws and cutlery, in the European Union. In May 2019, Maine became the first US state to prohibit businesses from using Styrofoam. Pressure to save wildlife led manufacturers to create edible plastic six-pack rings made of barley and wheat, which are used in the beer brewing process.

In May 2021, the Minderoo Foundation, an Australian philanthropic organization, published a study by researchers from the London School of Economics, the Stockholm Environment Institute, and others. Called the Plastic Waste Makers Index, the study named the twenty petrochemical companies—ExxonMobil, Dow, and Sinopec among them—responsible for making the polymers used in 55 percent the world's single-use plastic waste, as well as the one hundred companies responsible for producing 90 percent of the world's single-use plastic. The study named the twenty global banks, including Bank of America, Barclays, and HSBC, responsible for funding 60 percent of the industry's commercial financing. The study also assessed nations' single-use plastic production per person and found that in 2019, the US and Australia produced more than 50 kilograms of throwaway plastic per person, while the UK and South Korea each produced 44 kilograms per person.

In March 2022, United Nations member states convened for the UN Environment Assembly. On March 2, leaders and representatives from 200 countries signed a historic resolution with the goal of ending plastic pollution. The signatory nations agreed to establish the Intergovernmental Negotiating Committee (INC) on Plastic Pollution to begin working on a legally binding international treaty to address the production, design, and disposal of plastic.

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