Most of the plastic trash in the oceans, Earth’s last sink, flows from land. Trash is also carried to sea by major rivers, which act as conveyor belts, picking up more and more trash as they move downstream. Once at sea, much of the plastic trash remains in coastal waters. But once caught up in ocean currents, it can be transported around the world.
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On Henderson Island, an uninhabited atoll in the Pitcairn Group isolated halfway between Chile and New Zealand, scientists found plastic items from Russia, the United States, Europe, South America, Japan, and China. They were carried to the South Pacific by the South Pacific gyre, a circular ocean current.
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Once at sea, sunlight, wind, and wave action break down plastic waste into small particles, often less than one-fifth of an inch across. These so-called microplastics are spread throughout the water column and have been found in every corner of the globe, from Mount Everest, the highest peak, to the Mariana Trench, the deepest trough.
Microplastics are breaking down further into smaller and smaller pieces. Plastic microfibers, meanwhile, have been found in municipal drinking water systems and drifting through the air.
It's no surprise then that scientists have found microplastics in people. The tiny particles are in our blood, lungs, and even in feces. Exactly how much microplastics might be harming human health is a question scientists are urgently trying to answer. (Learn more.)
Millions of animals are killed by plastics every year, from birds to fish to other marine organisms. Nearly 700 species, including endangered ones, are known to have been affected by plastics. Nearly every species of seabird eats plastics.
Most of the deaths to animals are caused by entanglement or starvation. Seals, whales, turtles, and other animals are strangled by abandoned fishing gear or discarded six-pack rings. Microplastics have been found in more than 100 aquatic species, including fish, shrimp, and mussels destined for our dinner plates. In many cases, these tiny bits pass through the digestive system and are expelled without consequence. But plastics have also been found to have blocked digestive tracts or pierced organs, causing death. Stomachs so packed with plastics reduce the urge to eat, causing starvation.
Plastics have been consumed by land-based animals, including elephants, hyenas, zebras, tigers, camels, cattle, and other large mammals, in some cases causing death.
plastic pollution , accumulation in the environment of synthetic plastic products to the point that they create problems for wildlife and their habitats as well as for human populations . In 1907 the invention of Bakelite brought about a revolution in materials by introducing truly synthetic plastic resins into world commerce. By the end of the 20th century, plastics had been found to be persistent polluters of many environmental niches , from Mount Everest to the bottom of the sea . Whether being mistaken for food by animals , flooding low-lying areas by clogging drainage systems, or simply causing significant aesthetic blight , plastics have attracted increasing attention as a large-scale pollutant .
Plastic bottles and other garbage in a lake.
Plastic is a polymeric material—that is, a material whose molecules are very large, often resembling long chains made up of a seemingly endless series of interconnected links. Natural polymers such as rubber and silk exist in abundance, but nature’s “plastics” have not been implicated in environmental pollution, because they do not persist in the environment. Today, however, the average consumer comes into daily contact with all kinds of plastic materials that have been developed specifically to defeat natural decay processes—materials derived mainly from petroleum that can be molded, cast, spun, or applied as a coating. Since synthetic plastics are largely nonbiodegradable, they tend to persist in natural environments. Moreover, many lightweight single-use plastic products and packaging materials, which account for approximately 50 percent of all plastics produced, are not deposited in containers for subsequent removal to landfills, recycling centres, or incinerators. Instead, they are improperly disposed of at or near the location where they end their usefulness to the consumer. Dropped on the ground, thrown out of a car window, heaped onto an already full trash bin, or inadvertently carried off by a gust of wind, they immediately begin to pollute the environment. Indeed, landscapes littered by plastic packaging have become common in many parts of the world. (Illegal dumping of plastic and overflowing of containment structures also play a role.) Studies from around the world have not shown any particular country or demographic group to be most responsible, though population centres generate the most litter. The causes and effects of plastic pollution are truly worldwide.
recycling binsRecycling bins set side by side with trash bins.
According to the trade association PlasticsEurope, worldwide plastic production grew from some 1.5 million metric tons (about 1.7 million short tons) per year in 1950 to an estimated 275 million metric tons (about 303 million short tons) by 2010 and 359 million metric tons (nearly 396 million short tons) by 2018; between 4.8 million and 12.7 million metric tons (5.3 million and 14 million short tons) are discarded into the oceans annually by countries with ocean coastlines.
Compared with materials in common use in the first half of the 20th century, such as glass, paper, iron, and aluminum, plastics have a low recovery rate. That is, they are relatively inefficient to reuse as recycled scrap in the manufacturing process, because of significant processing difficulties such as a low melting point, which prevents contaminants from being driven off during heating and reprocessing. Most recycled plastics are subsidized below the cost of raw materials by various deposit schemes, or their recycling is simply mandated by government regulations. Recycling rates vary dramatically from country to country, and only northern European countries obtain rates greater than 50 percent. In any case, recycling does not really address plastic pollution, since recycled plastic is “properly” disposed of, whereas plastic pollution comes from improper disposal.