Question
"Biodegradable Plastic Bags, Not So Biodegradable"
by Vicky Stein
The average person uses a typical plastic bag for as short a time as 12 minutes before throwing it away, never thinking of where it may end up.
Yet once consigned to a landfill, that standard grocery store tote takes hundreds or thousands of years to break down — much more than a human lifetime. Bags make up an alarming amount of the plastic found in whale stomachs or bird nests, and it’s no wonder — globally, we use between 1 and 5 trillion plastic bags each year.
Biodegradable plastic bags are marketed as more eco-friendly solutions, able to break down into harmless material more quickly than traditional plastics. One company claims their shopping bag “will degrade and biodegrade in a continuous, irreversible and unstoppable process” if it ends up as litter in the environment.
In a study published this week in Environmental Science and Technology, researchers put supposedly eco-friendly bags made from various organic and plastic materials and sourced from U.K. stores to the test. After three years buried in garden soil, submerged in ocean water, exposed to open light and air or stashed in a laboratory, none of the bags broke down completely in all the environments.
In fact, the biodegradable bags that had been left underwater in a marina could still hold a full load of groceries.
“What is the role of some of these really innovative and novel polymers?” asked Richard Thompson, a marine biologist from the University of Plymouth and the study’s senior author. A polymer is a repeating chain of chemicals that makes up a plastic’s structure, whether biodegradable or synthetic.
“They’re challenging to recycle and are very slow to degrade if they become litter in the environment,” Thompson said, suggesting these biodegradable plastics may be causing more problems than they solve.
What the researchers did
The researchers collected samples of five types of plastic bags.
The first type was made of high-density polyethylene — the standard plastic found in grocery store bags. It was used as a comparison for four other bags labeled eco-friendly:
A biodegradable plastic bag made in part from oyster shells
Two kinds of bags made from oxo-biodegradable plastic, which contain additives that companies say helps plastic break down faster
A compostable bag made from plant products
Each bag type was placed in four environments. Whole bags and bags cut into strips were buried in garden soil outdoors, submerged in salt water in a marina, left
exposed to daylight and open air, or sealed in a dark container in a temperature-controlled lab.
Oxygen, temperature and light all change the structure of plastic polymers, said Julia Kalow, a polymer chemist from Northwestern University, who was not involved
in this study. So too can reactions with water and interactions with bacteria or other forms of life.
What the scientists found
Even in a tough marine environment, where algae and animals quickly covered the plastic, three years wasn’t long enough to break down any of the plastics except for the plant-based compostable option, which did disappear underwater within three months. The plant-derived bags, however, remained intact but weakened when buried under garden soil for 27 months.
The only treatment that consistently broke down all of the bags was exposure to open air for more than nine months, and in that case even the standard, traditional polyethylene bag disintegrated into pieces before 18 months had passed.
“I would take that timescale to be too long for these products to be regarded as providing an environmental advantage,” Thompson said.
Even if these bags take less time to break down than traditional plastic bags, as litter they would still have enough time to become potentially deadly food for ocean animals like seabirds, whales, turtles or fish. Moreover, they would still be an eyesore and take up space at waste facilities for months or years.
And when some of the plastic bags did seem to break down, such as the bags left to the open air, it was unclear if the disintegration was complete.
“Did the plastic that was lost just become smaller pieces of plastic?” Kalow asked, “Or did it become molecules that could dissolve in water and be consumed?”
Future studies, she said, should dig into the fate of those disintegrated plastic particles, to ascertain whether they truly break down and disappear — or become microplastics and harmful chemicals.
Why it matters
Even standard plastic bags can’t be recycled from your home recycling bin, so most end up in landfill or are swept away by water or wind, becoming litter.
Biodegradable and compostable bags are meant to solve these problems, but the study indicates that’s not the case so far.
These alternative bags aren’t meant to end up as litter in the street or in the natural environment — ideally, they’d all be treated just as manufacturers expect. Biodegradable bags would be landfilled or, in some cases, recycled into new plastics — at least in theory.
But “even if we can make something that’s recyclable, that doesn’t mean any commercial recycling plant would be interested in dealing with it,” Kalow said. Biodegradable plastics can’t generally be recycled with other plastics — in fact, they can ruin other batches of recyclable plastic, degrading the product until it becomes unusable.
Meanwhile, the eco-conscious should hope their compostable bags end up in industrial composting facilities where high temperatures and favorable conditions for bacteria and other living things would break them down. (Compostable bags in chilly, oxygen-starved landfills can actually be preserved rather than destroyed.
These are the real problems, Thompson said. Labels like “biodegradable,” “compostable” or even “recyclable” are theoretical — they don’t reflect the reality of what happens to the materials we throw away or litter into the oceans, and they don’t help people accurately understand how to get rid of them.
Three years after the researchers’ plastic bags were buried or submerged, they were nearly as useful — and as harmful — as the day they were made.
Some simple solutions might help. Thompson suggested that standardized products, made of the same sets of materials, could streamline our waste management systems and allow much more of our waste to be profitably recycled. Kalow, the polymer chemist, said there may yet be hope for new, improved biodegradable plastics if only we could discover that technology
In the meantime, it doesn’t hurt to remember your reusable bag on your way to the store.
© NewsHour Productions LLC. All Rights Reserved.
Question
Use the article to answer the question.
Why did the author include the “What the researchers did” section?
(1 point)
Responses
Biodegradable plastics are difficult to recycle and slow to biodegrade, which suggests that they may cause more problems than they solve.
Biodegradable plastics are difficult to recycle and slow to biodegrade, which suggests that they may cause more problems than they solve.
to show how researchers studied the decomposition of standard plastic bags compared to biodegradable ones
to show how researchers studied the decomposition of standard plastic bags compared to biodegradable ones
to show how new technology can help scientists develop new, improved biodegradable plastics
to show how new technology can help scientists develop new, improved biodegradable plastics
to show that biodegradable bags do not break down more easily than standard plastic bags
to show that biodegradable bags do not break down more easily than standard plastic bags
Skip to navigation
by Vicky Stein
The average person uses a typical plastic bag for as short a time as 12 minutes before throwing it away, never thinking of where it may end up.
Yet once consigned to a landfill, that standard grocery store tote takes hundreds or thousands of years to break down — much more than a human lifetime. Bags make up an alarming amount of the plastic found in whale stomachs or bird nests, and it’s no wonder — globally, we use between 1 and 5 trillion plastic bags each year.
Biodegradable plastic bags are marketed as more eco-friendly solutions, able to break down into harmless material more quickly than traditional plastics. One company claims their shopping bag “will degrade and biodegrade in a continuous, irreversible and unstoppable process” if it ends up as litter in the environment.
In a study published this week in Environmental Science and Technology, researchers put supposedly eco-friendly bags made from various organic and plastic materials and sourced from U.K. stores to the test. After three years buried in garden soil, submerged in ocean water, exposed to open light and air or stashed in a laboratory, none of the bags broke down completely in all the environments.
In fact, the biodegradable bags that had been left underwater in a marina could still hold a full load of groceries.
“What is the role of some of these really innovative and novel polymers?” asked Richard Thompson, a marine biologist from the University of Plymouth and the study’s senior author. A polymer is a repeating chain of chemicals that makes up a plastic’s structure, whether biodegradable or synthetic.
“They’re challenging to recycle and are very slow to degrade if they become litter in the environment,” Thompson said, suggesting these biodegradable plastics may be causing more problems than they solve.
What the researchers did
The researchers collected samples of five types of plastic bags.
The first type was made of high-density polyethylene — the standard plastic found in grocery store bags. It was used as a comparison for four other bags labeled eco-friendly:
A biodegradable plastic bag made in part from oyster shells
Two kinds of bags made from oxo-biodegradable plastic, which contain additives that companies say helps plastic break down faster
A compostable bag made from plant products
Each bag type was placed in four environments. Whole bags and bags cut into strips were buried in garden soil outdoors, submerged in salt water in a marina, left
exposed to daylight and open air, or sealed in a dark container in a temperature-controlled lab.
Oxygen, temperature and light all change the structure of plastic polymers, said Julia Kalow, a polymer chemist from Northwestern University, who was not involved
in this study. So too can reactions with water and interactions with bacteria or other forms of life.
What the scientists found
Even in a tough marine environment, where algae and animals quickly covered the plastic, three years wasn’t long enough to break down any of the plastics except for the plant-based compostable option, which did disappear underwater within three months. The plant-derived bags, however, remained intact but weakened when buried under garden soil for 27 months.
The only treatment that consistently broke down all of the bags was exposure to open air for more than nine months, and in that case even the standard, traditional polyethylene bag disintegrated into pieces before 18 months had passed.
“I would take that timescale to be too long for these products to be regarded as providing an environmental advantage,” Thompson said.
Even if these bags take less time to break down than traditional plastic bags, as litter they would still have enough time to become potentially deadly food for ocean animals like seabirds, whales, turtles or fish. Moreover, they would still be an eyesore and take up space at waste facilities for months or years.
And when some of the plastic bags did seem to break down, such as the bags left to the open air, it was unclear if the disintegration was complete.
“Did the plastic that was lost just become smaller pieces of plastic?” Kalow asked, “Or did it become molecules that could dissolve in water and be consumed?”
Future studies, she said, should dig into the fate of those disintegrated plastic particles, to ascertain whether they truly break down and disappear — or become microplastics and harmful chemicals.
Why it matters
Even standard plastic bags can’t be recycled from your home recycling bin, so most end up in landfill or are swept away by water or wind, becoming litter.
Biodegradable and compostable bags are meant to solve these problems, but the study indicates that’s not the case so far.
These alternative bags aren’t meant to end up as litter in the street or in the natural environment — ideally, they’d all be treated just as manufacturers expect. Biodegradable bags would be landfilled or, in some cases, recycled into new plastics — at least in theory.
But “even if we can make something that’s recyclable, that doesn’t mean any commercial recycling plant would be interested in dealing with it,” Kalow said. Biodegradable plastics can’t generally be recycled with other plastics — in fact, they can ruin other batches of recyclable plastic, degrading the product until it becomes unusable.
Meanwhile, the eco-conscious should hope their compostable bags end up in industrial composting facilities where high temperatures and favorable conditions for bacteria and other living things would break them down. (Compostable bags in chilly, oxygen-starved landfills can actually be preserved rather than destroyed.
These are the real problems, Thompson said. Labels like “biodegradable,” “compostable” or even “recyclable” are theoretical — they don’t reflect the reality of what happens to the materials we throw away or litter into the oceans, and they don’t help people accurately understand how to get rid of them.
Three years after the researchers’ plastic bags were buried or submerged, they were nearly as useful — and as harmful — as the day they were made.
Some simple solutions might help. Thompson suggested that standardized products, made of the same sets of materials, could streamline our waste management systems and allow much more of our waste to be profitably recycled. Kalow, the polymer chemist, said there may yet be hope for new, improved biodegradable plastics if only we could discover that technology
In the meantime, it doesn’t hurt to remember your reusable bag on your way to the store.
© NewsHour Productions LLC. All Rights Reserved.
Question
Use the article to answer the question.
Why did the author include the “What the researchers did” section?
(1 point)
Responses
Biodegradable plastics are difficult to recycle and slow to biodegrade, which suggests that they may cause more problems than they solve.
Biodegradable plastics are difficult to recycle and slow to biodegrade, which suggests that they may cause more problems than they solve.
to show how researchers studied the decomposition of standard plastic bags compared to biodegradable ones
to show how researchers studied the decomposition of standard plastic bags compared to biodegradable ones
to show how new technology can help scientists develop new, improved biodegradable plastics
to show how new technology can help scientists develop new, improved biodegradable plastics
to show that biodegradable bags do not break down more easily than standard plastic bags
to show that biodegradable bags do not break down more easily than standard plastic bags
Skip to navigation
Answers
GPT-4o mini
The author included the “What the researchers did” section **to show how researchers studied the decomposition of standard plastic bags compared to biodegradable ones**.
Question
Use the paragraph to answer the question.
Humans have observed the stars twinkling in the sky since the beginning of recorded history. But over the years, what they mean to us has grown and evolved. New telescope technology currently under development could have a huge impact on what we know—or what we think we know—about the stars today.
Based on the thesis statement in the paragraph, what will the text be about?
(1 point)
Responses
why it is important to continue to study the stars and develop new and improved telescope technology
why it is important to continue to study the stars and develop new and improved telescope technology
the history of telescope technology and how the human understanding of stars has evolved
the history of telescope technology and how the human understanding of stars has evolved
telescope technology that is in development right now and how it could change our understanding of stars
telescope technology that is in development right now and how it could change our understanding of stars
how new telescope technology is revealing our past misconceptions about the stars
how new telescope technology is revealing our past misconceptions about the stars
Skip to navigation
Use the paragraph to answer the question.
Humans have observed the stars twinkling in the sky since the beginning of recorded history. But over the years, what they mean to us has grown and evolved. New telescope technology currently under development could have a huge impact on what we know—or what we think we know—about the stars today.
Based on the thesis statement in the paragraph, what will the text be about?
(1 point)
Responses
why it is important to continue to study the stars and develop new and improved telescope technology
why it is important to continue to study the stars and develop new and improved telescope technology
the history of telescope technology and how the human understanding of stars has evolved
the history of telescope technology and how the human understanding of stars has evolved
telescope technology that is in development right now and how it could change our understanding of stars
telescope technology that is in development right now and how it could change our understanding of stars
how new telescope technology is revealing our past misconceptions about the stars
how new telescope technology is revealing our past misconceptions about the stars
Skip to navigation
GPT-4o mini
Based on the thesis statement in the paragraph, the text will be about **telescope technology that is in development right now and how it could change our understanding of stars**.
Use the scenario to answer the question.
You want to write an essay about the fashion industry. You hope to help the audience understand how the three biggest clothing manufacturers operate, and why one might be better to support than the others.
Which text structure would best fit this essay?
(1 point)
Responses
cause and effect
cause and effect
sequential
sequential
compare and contrast
compare and contrast
problem and solution
You want to write an essay about the fashion industry. You hope to help the audience understand how the three biggest clothing manufacturers operate, and why one might be better to support than the others.
Which text structure would best fit this essay?
(1 point)
Responses
cause and effect
cause and effect
sequential
sequential
compare and contrast
compare and contrast
problem and solution
GPT-4o mini
The text structure that would best fit this essay is **compare and contrast**. This structure would allow you to evaluate and highlight the differences and similarities between the three biggest clothing manufacturers, helping the audience understand which one might be better to support.
Use the description to answer the question.
A writer is creating a guide to help children learn how to take care of their first pet.
What items will the writer most likely use to develop the topic? Select the two correct answers.
(1 point)
Responses
quotations from experts
quotations from experts
statistics from scientific studies
statistics from scientific studies
simple explanations of basic ideas
simple explanations of basic ideas
specialized or academic language
specialized or academic language
examples that support claims
A writer is creating a guide to help children learn how to take care of their first pet.
What items will the writer most likely use to develop the topic? Select the two correct answers.
(1 point)
Responses
quotations from experts
quotations from experts
statistics from scientific studies
statistics from scientific studies
simple explanations of basic ideas
simple explanations of basic ideas
specialized or academic language
specialized or academic language
examples that support claims
GPT-4o mini
The writer will most likely use **simple explanations of basic ideas** and **examples that support claims** to develop the topic of helping children learn how to take care of their first pet. These items would be appropriate for the target audience.
Use the sentence to answer the question.
I chose the drapes, wallpaper, and rug for the new room.
Which sentence conveys the same idea using passive voice?
(1 point)
Responses
The drapes, wallpaper, and rug for the new room are decorations I selected.
The drapes, wallpaper, and rug for the new room are decorations I selected.
Oh, these drapes, wallpaper, and rug I chose for the new room are perfect!
Oh, these drapes, wallpaper, and rug I chose for the new room are perfect!
Please choose drapes, wallpaper, and a rug for the new room.
Please choose drapes, wallpaper, and a rug for the new room.
The drapes, wallpaper, and rug for the new room were chosen by me.
The drapes, wallpaper, and rug for the new room were chosen by me.
I chose the drapes, wallpaper, and rug for the new room.
Which sentence conveys the same idea using passive voice?
(1 point)
Responses
The drapes, wallpaper, and rug for the new room are decorations I selected.
The drapes, wallpaper, and rug for the new room are decorations I selected.
Oh, these drapes, wallpaper, and rug I chose for the new room are perfect!
Oh, these drapes, wallpaper, and rug I chose for the new room are perfect!
Please choose drapes, wallpaper, and a rug for the new room.
Please choose drapes, wallpaper, and a rug for the new room.
The drapes, wallpaper, and rug for the new room were chosen by me.
The drapes, wallpaper, and rug for the new room were chosen by me.
GPT-4o mini
The sentence that conveys the same idea using passive voice is **The drapes, wallpaper, and rug for the new room were chosen by me.**
Use the sentences to answer the question.
Millions of books are purchased every year. However, authors only collect a small fraction of the profit.
How does the effectiveness of the two sentences compare?
(1 point)
Responses
They are equally effective.
They are equally effective.
The first is more effective.
The first is more effective.
The second is more effective.
The second is more effective.
Neither sentence is effective.
Neither sentence is effective.
Skip to navigation
Millions of books are purchased every year. However, authors only collect a small fraction of the profit.
How does the effectiveness of the two sentences compare?
(1 point)
Responses
They are equally effective.
They are equally effective.
The first is more effective.
The first is more effective.
The second is more effective.
The second is more effective.
Neither sentence is effective.
Neither sentence is effective.
Skip to navigation
GPT-4o mini
The second is more effective.