Want to learn more about
Plastic Pollution?
Plastic pollution is the accumulation, in the environment, of synthetic plastic products to the point that they create problems for wildlife and 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 were 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.
The problem
with plastics
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.
Because 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 centers 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 rubbish 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 centers generate the most litter. The causes and effects of plastic pollution are truly worldwide.
According to the trade association PlasticsEurope, world plastic production grew from some 1.5 million tonnes (about 1.7 million tons) per year in 1950 to an estimated 275 million tonnes (303.1 million tons) by 2010 and 381 million tonnes (420 million tons) by 2015. Between 4.8 million and 12.7 million tonnes (5.3 million and 14 million tons) are discarded into the oceans annually by countries with ocean coastlines.
The Great Pacific Garbage Patch is an island of discarded plastic that is now three times the size of France.
Some organisms thrive off discarded plastic, forming a new type of ecosystem called a “plastisphere.”
Scientists have found plastic bags at the bottom of the Mariana Trench, 36,000 feet below sea level.
Every year, 18 billlion pounds of plastic seeps into oceans from coasts.
Plastic Pollution
in oceans and on land
Because the ocean is downstream from nearly every terrestrial location, it is the receiving body for much of the plastic waste generated on land. Several million tonnes of debris end up in the world’s oceans every year, and much of it is improperly discarded plastic litter. The first oceanographic study to examine the amount of near-surface plastic debris in the world’s oceans was published in 2014. It estimated that at least 5.25 trillion individual plastic particles weighing roughly 244,000 tonnes (269,000 tons) were floating on or near the surface. Plastic pollution was first noticed in the ocean by scientists carrying out plankton studies in the late 1960s and early 1970s, and oceans and beaches still receive most of the attention of those studying and working to abate plastic pollution. Floating plastic waste has been shown to accumulate in five subtropical gyres that cover 40 percent of the world’s oceans. Located at Earth’s midlatitudes, these gyres include the North and South Pacific Subtropical Gyres, whose eastern “garbage patches” (zones with high concentrations of plastic waste circulating near the ocean surface) have garnered the attention of scientists and the media. The other gyres are the North and South Atlantic Subtropical Gyres and the Indian Ocean Subtropical Gyre.
In the ocean, plastic pollution can kill marine mammals directly through entanglement in objects such as fishing gear. It can also kill through ingestion, by being mistaken for food. Studies have found that all kinds of species, including small zooplankton, large cetaceans, most seabirds and all marine turtles, readily ingest plastic bits and trash items such as cigarette lighters, plastic bags and bottle caps. Sunlight and seawater embrittle plastic, and the eventual breakdown of larger objects into “microplastics” makes plastic available to zooplankton and other small marine animals. Such small pieces of plastic, which are less than 5 mm (0.2 inch) in length, make up a sizable fraction of plastic waste in the oceans. By 2018, microplastics had been found in the organs of more than 114 aquatic species, including some species found only in the deepest ocean trenches.
There are also terrestrial aspects to plastic pollution. Drainage systems become clogged with plastic bags, films and other items, causing flooding. Land birds, such as the reintroduced California condor, have been found with plastic in their stomachs, and animals that normally feed in waste dumps—for instance, the sacred cows of India—have had intestinal blockages from plastic packaging. The mass of plastic is not greater than that of other major components of waste, but it takes up a disproportionately large volume. As waste dumps expand in residential areas, the scavenging poor are often found living near or even on piles of residual plastics.
Pollution
by plastics additives
Plastic also pollutes without being littered—specifically, through the release of compounds used in its manufacture. Indeed, pollution of the environment by chemicals leached from plastics into air and water is an emerging area of concern. As a result, some compounds used in plastics, such as phthalates, bisphenol A (BPA) and polybrominated diphenyl ether (PBDE), have come under close scrutiny and regulation. Phthalates are plasticizers—softeners used to make plastic products less brittle. They are found in medical devices, food packaging, automobile upholstery, flooring materials and computers, as well as in pharmaceuticals, perfumes and cosmetics. BPA, used in the manufacture of clear, hard polycarbonate plastics and strong epoxy coatings and adhesives, is present in packaging, bottles, compact discs, medical devices and the linings of food cans. PBDE is added to plastics as a flame retardant. All these compounds have been detected in humans and are known to disrupt the endocrine system. Phthalates act against male hormones and are therefore known as anti-androgens; BPA mimics the natural female hormone estrogen; and PBDE has been shown to disrupt thyroid hormones in addition to being an anti-androgen. The people most vulnerable to such hormone-disrupting chemicals are women of reproductive age and children.
These compounds have also been implicated in the hormone disruption of animals in terrestrial, aquatic and marine habitats. Effects are seen in laboratory animals at blood levels lower than those found in the average resident of a developed country. Amphibians, mollusks, worms, insects, crustaceans and fish show effects on their reproduction and development, including alterations in the number of offspring produced, disruption of larval development and (in insects) delayed emergence—though studies investigating resulting declines in those populations have not been reported. Studies are needed to fill this knowledge gap, as are studies of the effects of exposure to mixtures of those compounds on animals and humans.
Given the global scale of plastic pollution, the cost of removing plastics from the environment would be prohibitive. Most solutions to the problem of plastic pollution, therefore, focus on preventing improper disposal or even on limiting the use of certain plastic items in the first place. Fines for littering have proved difficult to enforce, but various fees or outright bans on foamed food containers and plastic shopping bags are now common, as are deposits redeemed by taking beverage bottles to recycling centers. So-called extended producer responsibility, or EPR, schemes make the manufacturers of some items responsible for creating an infrastructure to take back and recycle the products that they produce. Awareness of the serious consequences of plastic pollution is increasing, and new solutions, including the increasing use of biodegradable plastics and a “zero-waste” philosophy, are being embraced by governments and the public.