Plastic Pollution

Overview

“Plastic” refers to a wide range of synthetic (human-made) materials composed mainly of substances called polymers (chemicals consisting of very large molecules composed of repeating subunits). Most modern plastic polymers are derived from chemicals made from petroleum (petrochemicals), but a small amount is made from materials derived from plants, including cellulose or starch.

The first synthetic plastic – Bakelite – was produced in 1907, marking the beginning of the global plastics industry, but rapid growth in plastic production didn’t happen until the 1950s. Since then, annual production of plastic has increased enormously.

Plastic is useful for many reasons, and plays a crucial role in modern life in literally countless ways. Essential activities such as manufacturing, communications, medicine, and especially the food supply chain would be impossible in their present form without plastic. It has allowed many technological advances, such as vastly improved food and medicine storage, lighter weight vehicles, and a multitude of consumer, industrial, and commercial uses – from pens, signs, and medical equipment to clothing, car, and spacecraft.

But plastic – in its production, use, and disposal – also produces huge and growing problems for the entire Earth. Addressing this situation is an enormous challenge, equal in magnitude in many ways to climate change. It will not be easy to solve and will inevitably involve difficult tradeoffs.

The "good news" is that people, organizations, and governments around the world are increasingly recognizing this as an urgent environmental problem. Research on the scope of and possible solutions to challenges posed by plastic production and disposal is increasing rapidly, and numerous initiatives are underway to address it.

What's Wrong with Plastic?

Plastic lasts a long time. Unlike many materials that people throw away – such as cardboard, natural fiber, or even metal – plastic lasts a long time. Most plastics do not break down (degrade) quickly when they are discarded, and that means they persist in the environment, causing long-term problems for living systems. (Plastics that break down due to the action of bacteria are called biodegradable. They cause fewer environmental problems, but extremely little of today's mass-produced plastic is biodegradable.) The combination of plastic's harmfulness and persistence means that its continuing production, use, and disposal are leading to what one recent study has called the "near-permanent contamination of the natural environment".

Some plastic can be hazardous to our health. Although some plastics are relatively inert and thought to be safe for most uses (such as food packaging), other plastics can be chemically harmful to living things, including humans. Most modern mass-produced plastics are made from petrochemicals containing toxic compounds (or they contain toxic additives) which can cause a wide array of health problems, from cancer to immune disorders. The sheer volume of plastic being produced today means we are putting vast quantities of these compounds into the environment where we (and every other living thing) cannot help but encounter them.

In addition to its own toxicity, some plastics can carry other toxic substances long distances. For example, plastic debris in the ocean is associated with persistent organic pollutants (POPs), including polychlorinated biphenyls (PCBs), pesticides, and polycyclic aromatic hydrocarbons (PAHs), due to the affinity of these molecules for some kinds of plastic. When plastic is incinerated, many of the toxic chemicals in it are put into the atmosphere.

Plastic that is very durable (non-degradable) can also cause physical damage to living things. For example, plastic waste may look like food to many wild animals, but when they consume it, they cannot digest it. In general, plastic (whether it is chemically toxic or not) can cause many kinds of serious physical damage to animals, such as choking, drowning, starvation, amputation, and other trauma. This is a particular problem for plastic waste in the ocean.

Plastic contributes to climate change. Plastic contributes to climate change in several ways, mainly in the energy required to produce it. Most of the energy for making plastic comes from fossil fuels which release greenhouse gasses, and producing plastic from "virgin" (i.e., not recycled) materials generally takes more energy than doing so from recovered/recycled materials. Disposing of plastic by burning it also produces greenhouse gasses. 

The Life of Plastics

Plastic has a "life cycle"; it is produced, used, and discarded. The effects of plastic on Earth's life and environments depends on what happens during each of these phases.

Where does plastic come from? 

Historically, the raw material for most plastic has been primarily a low-density component of crude oil made up of several categories of relatively small hydrocarbons (molecules containing hydrogen and carbon), including paraffins, naphthalenes, and aromatics. These molecules can, however, also come from other sources, including natural gas (methane, ethane, propane), coal, biomass, and recycled plastic.

Crude oils from different sources vary in their chemistry (for example, in the total amount and/or ratios of paraffins, naphthalenes, and aromatics). The chemical make-up of the different kinds of hydrocarbons influences what kinds of plastics can be produced from them. To make plastic from hydrocarbons, the molecules must be broken ("cracked") into smaller molecules (monomers). These monomers can then be put back together into larger chained polymers to form different kinds of plastics.

How much plastic is there? 

Plastic production is manufacturing, or making plastic from raw materials. Plastic use is how much plastic is purchased. Plastic waste is how much is thrown away (discarded) after it is used. These terms are not always used the same way and can be easily confused. Further confusion comes from the sources of discarded plastic – for example, large-scale commercial vs. municipal (which usually includes small-scale commercial and household). Reporting requirements also vary widely across the U.S. and around the world, making it frequently very difficult to gather reliable data.

Estimates of annual global plastic production today range from around 200 to more than 400 million tons. This has been expressed as roughly equal to the weight of more than 1,000 Empire State Buildings every year. It has been estimated that more than 9 billion tons of plastic has been produced since 1950.

Larger, more populous countries tend to use (and throw away) more plastic overall, but when the data are analyzed per person, the ranking changes significantly. China produces the most plastic of any nation, while the U.S. uses the most. Micronesia throws away the most per capita.

The U.S. produces enough plastic every year for the average American to use about 350 pounds annually. Plastic may be used for a few moments (such as a food wrapper, drink cup, or shopping bag; these are called single-use) or for many years (such as a piece of clothing, car bumper, or construction material). About 50% of the plastic produced each year is single-use. One estimate suggests that around 75% of the plastic produced globally each year reaches the end of its useful lifetime and is discarded; then it is called plastic waste. The average American probably throws away about 270 pounds of plastic waste each year, or about 22.5 pounds each month.

Where does plastic go after it is used? 

There are currently four major ways of disposing of plastic waste. When it is discarded, plastic can end up in landfills, or it can be burned (incinerated), recycled, or simply dumped, on land or in water bodies, from which it frequently makes its way to the ocean. (Dumped plastic is sometimes referred to as "mismanaged".)

Production, use, and disposal of plastics differ greatly around the world. While many high-income countries generate high amounts of plastic waste per person, they are also typically better at processing it more safely, whereas lower-income countries that are still developing their infrastructure tend to produce and use a higher percentage of mismanaged waste plastic.

Burning

A recent estimate indicates that about 13% of all the plastic ever discarded was burned. In 2014, incineration of non-fiber plastic peaked at 21% in 1995 before decreasing to 16% in 2014. The U.S. thus currently burns about twice as much plastic as it recycles.

Landfills & Dumping

Recycling

About 8-9% of the world's discarded plastic is recycled each year, but this varies significantly by country and kind of plastic. In 2014, for example, about 18% of non-fiber plastic was recycled globally, but that ranged from 30% in Europe and 25% in China to about 9% in the U.S. About 10% of all plastic ever recycled was recycled more than once.

How long does plastic last? 

Some of the properties that make plastic useful – including stability, durability, biological inertness, and impermeability – mean that it may last a long time after it is discarded. All plastic does "break down" or "degrade" eventually, but this occurs in several ways, all of which can vary significantly depending on environmental conditions. Plastic degradation can include physical breakage and fragmentation as well as chemical alteration into smaller molecules or even eventually into very simple compounds.

Plastic hasn't been around long enough for us to know exactly how long it takes for these processes to occur, so estimates are based on laboratory experiments and extrapolations. Unfortunately, we still don't know enough about these processes.

Plastic in the Ocean

Because rivers drain the land and most rivers eventually flow into the ocean, the ocean is the ultimate recipient of much of the world's plastic waste. And this has become an enormous environmental problem. It is estimated that between 1 million and 14 million metric tons (i.e., between about 2.2 million and 31 million pounds) of plastic enters the Earth's oceans each year. At this rate, some researchers suggest that by 2050 there could be more plastic than fish in the oceans by weight.

A 2014 estimate found that there were approximately 86 million tons of plastic in the world's oceans, equivalent to 1.4% of all plastic produced from 1950 to 2013. Another study indicates that this marine plastic includes more than 5 trillion individual plastic pieces with more than 250,000 tons floating at any one time.

Large scale concentrated accumulations of plastics have been found in the South Pacific subtropical gyre and the Eastern Pacific Ocean gyre. For example, the Great Pacific Garbage Patch is an expanse in the North Pacific Ocean more than twice the size of Texas where discarded plastic accumulates because of converging currents.

Different types of plastic waste dominate in different parts of the ocean. "Take-out" consumer items (mainly plastic bags and wrappers, food containers and cutlery, and plastic and glass bottles) make up the largest share in nearshore environments, but ocean-based activities such as fishing are the main source for plastic in the open ocean. Taken together, the top ten products, in descending order, were bags (14% across environments), plastic bottles (12%), food containers and cutlery (9%), wrappers (9%), synthetic ropes (8%), fishing-related items (for example, strings, threads, buoys; 8%), plastic caps and lids (6%), industrial packaging (3%), and glass bottles (3%).

It has been estimated that nearly 90% of the plastic entering the ocean comes from just 10 rivers, all located in Asia or Africa. In other words, much of the plastic going into the ocean every year comes from countries with poor or non-existent waste management infrastructure (such as landfills and transport systems), even though it may have been manufactured in countries that have such infrastructure.

Lost or discarded fishing gear – including nets, lines, and buoys – is a major source of plastic waste in the oceans. Millions of marine animals are unintentionally killed every year by these plastics that strangle, drown, or lacerate them. For example, North Atlantic right whales off New England are frequently tangled in plastic line from lobster traps or fishing nets. PRI's right whale #2030, whose skeleton is displayed in the Museum of the Earth, died for exactly this reason in 2000.

Plastic waste in the ocean is the source of a new kind of rock that is increasingly found on beaches in many parts of the world. This rock – called "plastic rock" or "plastistone" – is a combination of discarded plastic and sediment (sand or gravel), that forms as the plastic degrades and changes as it floats in the water. It has now been found on the shores of five continents.

Efforts to remove plastic from the ocean vary from small-scale beach cleanups to large-scale projects.

The negative impact of plastic on marine life is severe and growing. Hundreds of marine species have been observed to interact directly with plastic debris through ingestion, entanglement, and/or smothering. Many marine animals, from whales to birds, have been found with large amounts of plastic in their digestive systems. More than a third of dead leatherback turtles – the world's largest species of turtle – have ingested plastic. The polyethylene rope used for fishing and lobstering gear is a major source of entanglement for marine animals.

Microplastics

Microplastics, defined as tiny pieces of plastic with the longest dimension being less than 5 millimeters (0.2 inches), have become ubiquitous in Earth's environments; they are almost literally everywhere, from the top of Mount Everest to the deepest part of the oceans, from the Finger Lakes to waters around Antarctica.

Microplastics, in turn, can break down into even smaller pieces called nanoplastics, which are less than 1 μm in size, so small that you cannot see them with the naked eye. The small size of nanoplastics makes them especially difficult to detect and study.

Micro- and nanoplastics have been found in numerous species of wildlife, from fish to birds to insects. They occur in many human drinking water sources: a recent study of three popular brands of bottled water found that, on average, a liter of bottled water included about 240,000 tiny pieces of plastic, 90% of which were nanoplastics. They have been found throughout human bodies including blood, lungs, brain, placenta, and other organs. Although little is known definitively about their health effects, microplastics are suspected of causing numerous human health problems, including those of the respiratory, endocrine, cardio-vascular, and digestive systems.

Microplastics form by the physical breakdown of larger pieces of plastic, either by physical damage or by photodegradation in sunlight. Dumped plastic, which is exposed to daylight for extended periods, is an important source of microplastic (by photodegradation).

Another important and growing source is clothing fibers, including polyester, nylon, acrylic, and polypropylene. Such fibers make up approximately 14% of global plastic production. Global consumption of these synthetic fibers has increased greatly in recent years, and now accounts for at least 55% of the world's clothing market. Microfibers are released from clothing mainly by laundering (both washing and drying). Washing releases microfibers into wastewater, while drying releases them into the air. Wastewater treatment plants can remove up to 99% of microfibers, which are then retained in biosolids ("sludge"). These biosolids, however, are commonly used as additives to soil (although this is not currently the case in many areas, including in Tompkins County), which allows the microplastics to move into the environment where they may last for years.