In Part 1 of this blog series, we looked at the environmental and health implications of extracting raw materials–fossil fuels–for plastic products and the manufacture of those products, including single-use plastic bags. It’s hard to know how much of all plastic production goes towards making plastic bags specifically. We have an estimate of how many bags are produced each year–about 5 trillion.
In this post, we’ll look at the use and post-use fate of these bags and what that means for the environment. It isn’t pretty.
“Use” is fleeting
The use of those 5 trillion bags produced annually is, as you would expect, not evenly distributed worldwide. Americans consume about 365 bags per person per year; the typical citizen of Denmark uses an average of four bags per year.
A single-use plastic bag is typically “used” by the consumer for no more than 12 to 20 minutes.
The actual use of a single-use bag by the consumer represents a very brief part of its lifetime. Estimates vary, but the typical consumer uses a plastic bag anywhere from 12 to 20 minutes. Presumably, that’s the time it takes to get your groceries and other goods from the checkout to your home.
Many of us reuse plastic bags. We take them back to the store with us, use them as waste bin liners, or use them for dog-waste pickup, for example. Reuse extends the bags’ household lifetime, but not for long. Waste pickup, for example, is a “reuse once, then throw away” option. It’s all still just a drop in the life-cycle bucket.
Recyclable? Yes, but…
Once we’re done with our plastic bags, there are two responsible ways to deal with them–throw them in the trash, or recycle them. The latter is better than the former, but it’s not happening much, for bags or plastics generally. The Organization for Economic Co-operation and Development (OECD) estimates that, worldwide, 9% of all plastic waste is recycled while about 22% is mismanaged each year–that is, entering the environment rather than going to disposal facilities. The percentage of plastic bags returned for recycling in America is a miniscule 1%, according to the biggest North American waste management firm, appropriately named Waste Management.
In America, a miniscule 1% of single-use plastic bags is recycled each year.
Some of us mistakenly pack up recyclables into plastic bags and put them in the recycling bin. They’re plastic, right? Plastic can be recycled, Right? Unfortunately, It’s a bit more complicated than that.
The management chain for bags is different from the kinds of plastic–jugs, tubs, and bottles for kitchen, bath, and laundry products–that can go in the curbside bin. A bag in the bin is a big no-no. At the materials recycling facility (MRF) where we send our curbside recyclables, the bags have to be removed, typically by hand. If they’re missed–which happens all too often–they jam up the sorting machinery.
Operations shut down so that the bags can be removed, which can be hazardous for workers. It also costs each MRF thousands of dollars each year, costs that are passed on to the contracting municipalities and, therefore, to us.
Plastic bags and other types of plastic film are collected at some grocery stores, but is it all being recycled?
Although there are companies that reprocess plastic bags collected in bins you may have seen at grocery stores, there is a serious question about whether all those bags are actually being recycled. This is a claim that needs to be investigated. Of course, trucking any bags around the country to reprocessing facilities, which can be quite distant from your hometown, constitutes another contribution to greenhouse gas emissions. And then reprocessing recovered film and other plastics to make new products involves processes such as melting and granulation. These processes release a wide variety of toxic chemicals, such as volatile organic compounds (VOCs), cadmium, and arsenic, that pose health risks to workers in these facilities.
“Chemical recycling,” which burns plastic waste for fuel, releases toxic chemicals into the environment.
An emerging trend promoted by the plastics industry is “chemical recycling,” which involves the use of certain technologies, such as gasification and pyrolysis, to “recover” value from plastics. Environmental groups such as the Natural Resources Defense Council (NRDC) have studied chemical recycling and concluded that it isn’t recycling at all–just incineration by another name, designed to mislead the public and regulators (processes labeled as “recycling” typically receive regulatory relief from pollution management standards). Chemical recycling also releases toxic pollutants into the environment.
It bears repeating: Plastics recovery and recycling rates are very low–less than 10% for all plastics, 1 to 2% for single-use plastics. Recycling isn’t working for plastics, and plastic waste continues to increase dramatically.
Solid waste landfills emit noxious odors, leach pollutants into waterways, and are typically located near low-income or minority communities.
The other “responsible” form of waste management is throwing your single-use plastic bags into the trash. From there, they go to landfills or incinerators. Durham’s garbage is trucked 90 miles to a landfill in Sampson County. This facility is located near the historically black community of Snow Hill, which has raised concerns about the noxious smells coming from the landfill and the threat it poses to local water quality from leached contaminants. Reducing the total volume of Durham waste sent to Sampson County is an environmental justice priority, and removing bags from the equation would have a big impact. Of course, all solid-waste landfills emit carbon dioxide and methane, contributing to climate change.
Incineration offers no improvement over landfilling. Incinerators generate air pollution and toxic ash, exposure to which is associated with negative health impacts in workers and people in nearby communities.
Fugitive bags
A significant portion of plastic-bag waste finds its way into the environment, either because some consumers are litterbugs, or because the bags (and other trash) escape from garbage trucks, dumpsters, and waste management facilities. A recent report by the Minderoo-Monaco Commission on Plastics and Human Health estimates that about 22 megatons of plastic waste escape into the environment around the world each year.
Mismanagement of single-use plastic bags causes harm well beyond the eyesore of litter. Plastic bags often clog our drainage systems, causing flooding and imposing significant removal costs on municipalities. The drainage problems alone have prompted many cities and countries to ban single-use plastic bags.
Millions of tons of plastic waste and other garbage are picked up on beaches every year during the annual International Coastal Cleanup.
An enormous number of plastic bags find their way into our oceans from a variety of sources, mostly land-based. They circulate in ocean currents or wash up on beaches. The litter problem in coastal zones is daunting: In 2018, 1.9 million grocery bags and other plastic bags were picked up during the International Coastal Cleanup.
It is not known with certainty how long a plastic bag lasts in the environment; 1,000 years is a common estimate for degradation in landfills. Abiotic processes such as UV exposure, high temperatures, hydrolysis reactions, and mechanical damage break down plastics into smaller and smaller pieces and into their chemical components (recall from Part 1 of this blog series that some 10,000 chemicals are used in the production of plastic). The smallest pieces are known as microplastics and nanoplastics, which are measured in millimeters and micrometers in diameter. The microplastics, or “MPs,” are raising widespread concern about their health impacts and are a major focus of the health studies of plastics.
The chemicals that leach from plastics easily pass into the tissues of animals and have been found in whales, seabirds, and human beings.
A critical health issue is humans’ exposure to MPs and plastic chemicals as they bioaccumulate up the food chain. Phytoplankton and zooplankton get this process rolling by forming biofilms on plastic particles. Larger organisms then consume these particles, thinking they are food. This bioaccumulation has been observed in laboratory and field studies. Meanwhile, the chemicals that leach from plastics easily pass into the tissues of animals and have been found in whales, seabirds, and human beings.
Plastic particles and plastic chemicals have different effects on animals and humans; neither are good. MPs can cause cell membrane damage and inflammation and disrupt mitochondrial function. The mitochondria, you may remember from your first biology class, is the powerhouse of the cell, so we’re talking about the disruption of energy production here. Ingestion of the chemical compounds can lead to neurodevelopmental disorders, immune-system and endocrine-system dysfunction, reproductive impairment, cardiovascular disease, and cancer.
Sea turtles and other marine life suffer significant mortality from their “encounters” with plastic waste. (Photo credit: World Wildlife Fund)
Of course, plastic bags don’t have to break down into MPs and chemicals to cause trouble. The ingestion of intact waste (“biotic processes”) causes significant mortality in marine and terrestrial animals, Plastic bags are the most commonly found synthetic item in sea turtles’ stomachs; 34% of dead leatherback sea turtles were found to have ingested plastic. About 80% of seabirds, such as albatrosses and petrels, have plastic in their stomachs. Altogether, 663 species of marine animals have been found to suffer from the impacts of marine debris, and plastic waste is involved in virtually every encounter.
The list of environmental and health studies and observations is long and getting longer. The big take-away is, a bag that’s been disposed of may be out of sight and therefore out of mind, but it’s not out of body. Think about that the next time you put your groceries in a single-use plastic bag. Then think about replacing that bag with a reusable cloth bag. And then think about encouraging the Durham City Council to reduce the use of single-use bags by enacting the proposed fee program.