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A Better Way To Recycle Plastics | Earth Wise

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The global accumulation of plastic waste is an ever-growing problem.  At least five billion tons of the stuff has accumulated on land and sea and is even showing up in the bodies of animals and humans.  Recycling plastic instead of making even more of it seems like an essential thing to do but it has proven to be extremely challenging.

The main problem is that plastics come in many different varieties and the ways of breaking them down into a form that can be reused are very specific to each type of plastic.  Sorting plastic waste by plastic type is extremely impractical at large scale.  Certainly, most consumers can’t do it themselves.  As a result, most plastic gathered in recycling programs ends up in landfills.

New research at MIT has developed a chemical process using a catalyst based on cobalt that is very effective at breaking down a variety of plastics, including polyethylene and polypropylene, which are the two most widely produced plastics.   The MIT process breaks plastics down into propane.  Propane can be used as a fuel or as a feedstock for making many different products, including new plastics.

Plastics are hard to recycle because their long-chain molecules are very stable and difficult to break apart.  Most chemical methods for breaking their chemical bonds produce a random mix of different molecules which would somehow have to be sorted out in order to be useful for anything.

The new process uses a catalyst called a zeolite that contains cobalt nanoparticles.  The catalyst selectively breaks down various plastic polymer molecules and turns more than 80% of them into propane.

The researchers are still studying the economics and logistics of the method, but it looks quite promising.

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New process could enable more efficient plastics recycling

Photo, posted April 25, 2016, courtesy of NOAA Coral Reef Ecosystem Program via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Bidding ‘Adieu’ To Single-Use Plastics | Earth Wise

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Since the 1950s, more than nine billion tons of plastic have been produced, and 50% of that has been during the past 15 years.  While there are some use cases for plastic that are important, it generally serves as the poster child of our throwaway culture.

Plastic pollution can be found everywhere on earth, from the top of the tallest mountains to the bottom of the deepest oceans.  It’s in our food, water, and air. 

By 2040, researchers predict that there will be nearly 90 million tons of plastic pollution entering the environment each year.  By some estimates, single-use plastics account for half of all our plastic waste.    

Many cities, states, and even countries are limiting or even banning single-use plastics.  Canada recently announced a ban on single-use plastics.  The ban includes things like plastic shopping bags, cups, cutlery, straws, stirrers, and take-out food containers.

The ban will phase in over the next several years, beginning with a ban on the manufacture and import of single-use plastics by the end of this year.  Sales of these items will be prohibited in 2023, and the export of plastics will cease by the end of 2025.  

Canada’s southern neighbor, the United States, leads the world in plastic waste generation.  While some states have approved single-use plastic reforms, most of the effort at the federal level has focused on improving recycling rates.  However, a recent report from several environmental organizations found that plastic recycling rates in the U.S. have actually declined in the last several years, from an already-dismal 8.7% to less than 6%.    

Suggesting the plastic waste problem can be solved with improved recycling rates is greenwashing the issue. 

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Canada is banning single-use plastics, including grocery bags and straws

Photo, posted October 31, 2011, courtesy of Mara via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Sand From Mining Waste | Earth Wise

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The natural resources people use the most are air and water.  It may come as a surprise that in third place is sand.  Sand is used to make glass, computer chips, toothpaste, cosmetics, food, wine, paper, paint, plastics, and more.  It is estimated that 50 billion tons of sand are used each year.

Concrete is 10% cement, 15% water, and 75% sand.  The concrete required to build a house takes on average 200 tons of sand, a hospital uses 3,000 tons, and a mile of a highway requires 15,000 tons.

One would think that there is no shortage of sand, but we are using it up faster than the planet can make it and the extraction of sand from seas, rivers, beaches, and quarries has negative impacts on the environment and surrounding communities.  For example, removing sand leads to erosion in riverbanks, significantly increasing the risk of flooding in some places.

A potential strategy to reduce the impact of extracting sand to meet society’s growing need for is also a strategy for helping to reduce the production of mineral mining waste, which is the largest waste stream on the planet.  Mining produces between 33 and 66 billion tons of waste material each year.

A new study by researchers in Switzerland and Australia looked at the potential for using mining waste as a source of so-called ore-sand.  Sand-like material left over from mining operations could be used for many current applications for sand.  Separating and repurposing these materials before they are added to the waste stream would not only reduce the volume of waste being generated by mining operations but would also create a responsible new source of sand.

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Solution to world’s largest waste stream: Make sand

Photo, posted October 22, 2005, courtesy of Alan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Turning Pollution Into Cash | Earth Wise     

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Power plants and other industrial facilities are a major source of carbon emissions.  There are a variety of techniques under development to prevent those emissions by capturing them rather than releasing them into the atmosphere.  All of them add costs to the functioning of the facility.  A good way to offset those costs is to convert the emissions into useful products, ideally making it profitable to capture emissions.

Engineers at the University of Cincinnati have developed an electrochemical system that converts carbon dioxide into ethylene, which is a chemical used in a wide range of manufacturing.  Ethylene has sometimes been called “the world’s most important chemical”.  It is used in many kinds of plastics, textiles, and the rubber found in tires and insulation. It is also used in heavy industry such as steel and cement plants as well as in the oil and gas industry.

The Cincinnati process is a two-stage cascade reaction that converts carbon dioxide to carbon monoxide and then into ethylene.  It is based on the underlying principle of the plug-flow reactor that is used for variety of production applications.  The study, published in the journal Nature Catalysis, demonstrates that the process has high ethylene selectivity – meaning that it effectively isolates the desired compound – as well as high productivity – meaning that it makes a lot of it.  The system will take more time to become truly economical, but the researchers are continuing to make progress on that front with improved catalysts.

The researchers believe that this technique can reduce carbon emissions and make a profit doing it.  Power plants and other facilities emit a lot of carbon dioxide.  With this process, it may be possible to capture it and produce a valuable chemical.

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Conversion process turns pollution into cash

Photo, posted February 27, 2018, courtesy of Cyprien Hauser via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Getting Rid Of Single-Use Plastics | Earth Wise

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Single-use plastics are used only once before they are recycled – or more likely – simply thrown away.  These are things like plastic bags, straws, coffee stirrers, soda and water bottles, and most food packaging.  They are primarily made from fossil fuel-based chemicals.

Since the 1950s, over 9 billion tons of plastics have been produced, and half of that has been in the past 15 years.  There are uses for plastic that are not only reasonable, but are even important, such as for surgical gloves.  But for the most part, single-use plastic is the poster child of our throwaway culture that is bad for the environment, for wildlife, and even for human health.

Many cities, states, and even countries are moving toward greatly limiting or outright banning single-use plastics.  A recent global survey indicates that the great majority of people around the world are with the program.

According to a 28-country survey from marketing firm Ipsos and the activist group Plastic Free July, three out of four people around the world agree with a ban on single-use plastics.  The poll of more than 20,000 people showed that in Latin America, China, and India, more than 80% agree that a ban should happen as soon as possible.  Unfortunately, Canada, the United States, and Japan were the least supportive countries.  In particular, only 40% of Japanese respondents favored a ban.

Ninety percent of respondents globally support an international treaty to combat plastic pollution and eighty percent said they personally want to buy products with as little plastic packaging as possible.  Unfortunately, people in wealthy countries, which produce the most plastic waste, are less likely to support a ban.  Those countries typically export their waste to the developing world.

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Three in Four People Worldwide Support a Ban on Single-Use Plastics

Photo, posted April 13, 2006, courtesy of Leonard J Matthews via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Octopuses And Litter | Earth Wise

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Octopuses are remarkably intelligent animals.  They have a larger brain for their body size than all other animals apart from birds and mammals.  They exhibit high-order cognitive behaviors including tool use and problem solving.  Some captive octopuses learned to shoot jets of water at aquarium light switches to turn them off.  Others have learned to unscrew jar lids to get at food.

A recent analysis of underwater imaging has shown that octopuses are increasingly using discarded bottles, cans, and other human-generated litter as shelter or as a place to lay eggs.

The research documented 24 species of octopus sheltering inside glass bottles, cans, and even an old battery.  Some buried themselves under a mixture of bottle caps and seashells.  Others even carried plastic items around while walking on just two tentacles to disguise themselves from predators.

The octopuses showed a preference for unbroken items and for darker or opaque containers.  Normally, octopuses make use of natural shelters such as seashells.  Whether they are making use of litter simply because there is so much of it around or because there is an increasing lack of natural items is not clear.

As with all other aspects of the growing problem of litter in the oceans, this new trend is not a good one.  Sheltering or laying eggs inside discarded tires, batteries, or plastic items has the potential to expose octopuses to heavy metals and other harmful chemicals.

Octopuses are intelligent and resourceful animals, and they will use whatever they have at their disposal to continue sheltering or moving around with protection from potential predators.

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Octopuses Have Learned to Make Use of Ocean Litter, Study Finds

Photo, posted May 13, 2014, courtesy of Elias Levy via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

New York’s Polystyrene Foam Ban | Earth Wise

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As of January 1, the state of New York now prohibits any person engaged in the business of selling or distributing prepared food or beverages from selling, offering for sale, or distributing disposable food service containers that contain expanded polystyrene foam in the state.  In addition, no manufacturer will be allowed to sell, offer for sale, or distribute polystyrene loose fill packaging in the state.

In other words, there will be no more Styrofoam bowls, cartons, clamshell containers, lids, plates, trays, or packing peanuts.

There are still some exceptions.  Raw meat, seafood, poultry, or fish sold for the purpose of cooking or preparing off-premises can still be packaged in polystyrene foam.  Prepackaged food filled or sealed prior to receipt by a food service provider can also still be packaged in polystyrene foam.

The New York State Department of Environmental Conservation is initially focusing its efforts on outreach and education to achieve compliance rather than on enforcement.   The DEC has provided detailed regulations to assist stakeholders with complying with the law.

Expanded polystyrene foam is a major contributor to environmental litter.  The material breaks apart easily and does not readily biodegrade, causing it to be persistent in the environment and contribute to microplastic pollution.  The foam causes negative impacts to wildlife, waterways, and natural resources.

An estimated 65% of New Yorkers were already living in communities that banned polystyrene foam, notably including New York City and Long Island which imposed a ban in 2019. 

New York becomes the fourth state to impose such a ban after Maine, Maryland, and Vermont.  Colorado and Virginia will follow suit in the next two years.

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Expanded Polystyrene Foam Container and Polystyrene Loose Fill Packaging Ban

Photo, posted November 16, 2015, courtesy of Karim Ghantous via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Nanoplastics In The Air | Earth Wise

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The world is awash in plastic.  Discarded plastic litters our roadways, woodlands, and beaches.  It piles up in landfills.  Plastic enters the oceans by the millions of tons.  And plastic is finding its way even to remote and supposedly pristine parts of the world.

A team of researchers has found nanoplastics at the isolated high-altitude Sonnblick Observatory in the Austrian Alps.  This is the first time the particles were found in the area.  The researchers were looking for certain organic particles and only found the nanoplastics by chance.

The detected plastic particles were less than 200 nanometers in size, about one hundredth the width of a human hair.  It is highly unlikely that such particles originated in remote Alpine areas.

The researchers were looking for organic particles by taking samples of snow or ice, evaporating them, and then burning the residue to detect and analyze the vapors.  They described the detection method as essentially like a mechanical nose.  In this case, the nose smelled burning plastics in the form of polypropylene and polyethylene terephthalate.

Looking into the issue, the researchers found a strong correlation between high concentrations of nanoplastics and winds coming from the direction of major European cities – especially Frankfurt and the industrial Ruhr area of Germany, but also the Netherlands, Paris, and even London.

Modeling supports the idea that nanoplastics are transported by air from distant urban places.  This is particularly worrisome because it means that there are likely hotspots of nanoplastics in our cities and in the air that we are breathing.  Plastics appear to be everywhere.

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Nanoplastics found in the Alps, transported by air from Frankfurt, Paris and London

Photo, posted July 1, 2013, courtesy of Robert J. Heath via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Better Ways To Make Bioplastics | Earth Wise

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The world produces over 300 million tons of plastics each year, mostly produced from petroleum.  The environmental consequences are substantial and there is a critical need to replace as much of that plastic production with biodegradable plastics as possible.  Thus, there is global research aimed at making bioplastics more economical and as environmentally friendly as possible.

Researchers at Texas A&M University have developed an improved approach for making bioplastics from corn stubble, grasses, and mesquite agricultural production.  Apart from the obvious environmental benefits of having biodegradable plastics, producing bioplastics from common agricultural waste would create new revenue streams for farmers as well as the people who transport harvested feedstock and byproduct crops to refinery operations.

The key to bioplastic production is the efficient extraction and use of lignin, the organic polymer that is the primary structural support material in most plants.  The new research takes five conventional pretreatment technologies for plant materials and modifies them to produce both biofuel and plastics together at a lower cost.  The new method is called “plug-in preconditioning processes of lignin” and it can be directly and economically added into current biorefineries.  The process is designed to integrate dissolving, conditioning, and fermenting lignin, extracting energy from it and making it easily adaptable to biorefinery designs.

The so-called bioeconomy currently supports some 286,000 jobs.  Innovation is the key to achieving more widespread use of biodegradable plastic.  With improved economics of so-called lignocellulosic biorefineries, there can be new avenues to use agricultural waste to produce biodegradable plastics.

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‘Plugging in’ to produce environmentally friendly bioplastics

Photo, posted November 5, 2015, courtesy of Kathryn Faith via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Regulating Plastic Pollution | Earth Wise

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Much of the world is united in the desire to do something about the problem of plastic waste.  But putting in place regulations that transcend national borders is complicated.

One hundred fifteen countries have established bans on plastic bags, but globally, there are seven different definitions of what is considered a plastic bag.  Things like bag thickness can determine whether something even counts as a plastic bag.  These differences create loopholes that enable illegal bags to be used.  For a global company like Nestle, which sells food products in 187 countries, it means complying with 187 different sets of national regulations on plastic packaging.

At least 100 nations have expressed support for a global plastic treaty.  Preliminary talks are dealing with issues like setting a specific date to eliminate plastic from spilling into the ocean, creating a harmonized set of definitions and standards, coordination of national targets and plans, and creating a fund to build waste management facilities where they are most needed in less developed countries.

New plastic waste is created at a rate of over 300 million tons a year.   To date, 75% of all plastic ever produced has become waste, and plastic production is expected to triple by 2050.

With public concern about plastic waste growing and increasing support by countries around the world, there is growing optimism that a global treaty to address plastic waste could be approved on a pace that could make a difference.  Negotiations for international treaties can drag on for a decade or more.  There is not that kind of time to spare in this case, so perhaps urgency will drive more efficient action.

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Global treaty to regulate plastic pollution gains momentum

Photo, posted February 3, 2015, courtesy of Thad Zajdowicz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Plastic Pollution And The Galapagos Islands | Earth Wise

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The proliferation of plastics remains one of the world’s most challenging environmental problems.  Plastic pollution can be found in some of the most remote regions of the planet, including atop the world’s tallest mountains and in the deepest depths of the ocean.  Even the Galapagos Islands, a volcanic archipelago in the Pacific Ocean, are no exception.

According to a new study by researchers from the University of Exeter, the Galapagos Conservation Trust, and the Galapagos Science Center, plastic pollution has been found in seawater, on beaches, and inside marine animals at the Galapagos Islands. 

In the most polluted hotspots, more than 400 plastic particles were found per square metre of beach. The researchers found that only 2% of macroplastic pollution – plastic fragments larger than five millimeters – was identified as coming from the Galapagos islands. All seven of the marine invertebrate species examined – 52% of individuals tested – were found to contain microplastics.

Significant accumulations of plastic were also found in key habitats, including rocky lava shores and mangroves. In fact, plastics were found in all marine habitats at the island of San Cristobal, which is where Charles Darwin first landed in Galapagos.

Most of the plastic pollution in the Galapagos appears to arrive via ocean currents. According  to the research team, the highest levels of plastic pollution were found on east-facing beaches, which are exposed to pollution carried across the ocean on the Humboldt Current. 

The pristine images of the Galapagos, a world-famous biodiversity haven, might give the impression that the region is protected from plastic pollution.  But clearly that is not the case.

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Plastic in Galapagos seawater, beaches and animals

Photo, posted April 12, 2012, courtesy of Ben Tavener via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Marine Debris | Earth Wise

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Marine debris is a troubling issue around the world.  For most people, it is unsightly and perhaps inconvenient, but for many it is a critical problem that has serious impacts on many aspects of life.  This is especially the case for indigenous communities for whom the natural environment around the ocean is central to subsistence, recreation, culture, and economic opportunities.

The National Oceanic and Atmospheric Administration sponsors a Marine Debris Program that supports multiple projects.  In Alaska’s Pribilof Islands, the indigenous communities of St. George and St. Paul Islands conduct regular cleanups to protect and steward the natural resources that they depend on.  They make use of unmanned aircraft system surveys to target removal and monitoring efforts.

Another NOAA-sponsored program works to clean up the Maybeso Estuary in Alaska’s Prince of Wales Islands.  The project has removed 35,000 pounds of debris, freeing the flow of the salmon stream and restoring the area as a prime hotspot for fishing, boating, and outdoor recreation.

In Washington State’s Olympic Coast, the Makah Tribe has a project to locate and remove derelict crab pots and fishing lines from 80 miles of fishing area and marine sanctuary.  Derelict fishing gear can trap and entangle animals, degrade habitat, imperil navigation, and interfere with fishing.  The project team is working with tribal stakeholders on promoting marine debris awareness.

All of these communities have cared for the environment for generations, but marine debris poses perilous threats to their territories and community action is needed to preserve and protect these remarkable places.

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Lives and Livelihoods Disrupted by Marine Debris

Photo, posted September 11, 2015, courtesy of NOAA’s National Ocean Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Breaking Down Polystyrene | Earth Wise

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The proliferation of global plastic waste continues to be a growing problem for the world.  Hundreds of millions of tons of plastics are produced each year and most of it is used once and then discarded.  The properties that make plastics so attractive – durability and chemical stability – make it difficult to do anything with discarded plastics other than deposit them in landfills – where they don’t easily degrade over time – or burn them, which dumps carbon dioxide and various hazardous gases into the atmosphere.

Polystyrene is one of the most widely used plastics.  It is found in foam packaging materials, disposable food containers, plastic cutlery, storage containers, and many other places. 

Recycling plastics like polystyrene is generally not economically feasible.  Sorting plastics by type is time and labor intensive and the chemical processes required to break down plastics into usable precursor materials require significant energy input and the use of toxic solvents.

Recently, a team of scientists at Ames Laboratory in Iowa has developed a process based on ball-milling that deconstructs commercial polystyrene in a single step, at room temperature, in ambient atmosphere, and in the absence of harmful solvents.

Ball-milling is a technique that places materials in a milling vial with metal ball bearings which is then agitated to initiate a chemical reaction.  This approach is known as mechanochemistry.

The method represents an important breakthrough that enables dismantling of a polymer that includes its chemical breakdown without requiring solvents or the high temperatures generally needed to thermally decompose it.  This discovery opens up new avenues for low-temperature recovery of monomers from polymer-based systems that include composites and laminates.  It could be a very useful weapon in the battle against plastic waste.

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Polystyrene waste is everywhere, and it’s not biodegradable. Scientists just found a way to break it down.

Photo, posted December 11, 2010, courtesy of Warrenski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Sustainable Polymer From Wood | Earth Wise

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Scientists from the University of Bath in the UK have developed a sustainable polymer using xylose, a sugar found in wood.

The new polymer is a member of the polyether family.  It could be used in a variety of applications, including being a building block for polyurethane, used for example in mattresses and shoe soles. It could also be a bio-derived alternative to polyethylene glycol, a chemical widely used in biomedicine, or in polyethylene oxide, which is sometimes used as an electrolyte in batteries.

Xylose, also known as wood sugar, is one of the most abundant carbohydrates on earth, second only to glucose. Apart from comprising 5-20% of hardwoods, xylose is a major component of straw, corncobs, and many other plant materials.

The new polymer could reduce reliance on crude oil products and its properties can be easily controlled to make the material flexible or crystalline.  Added functionality could be added to it by binding other chemical groups such as fluorescent probes or dyes to the sugar molecule for biological or chemical sensing applications.

Tweaking the physical and chemical properties of bio-derived polymers has previously been a very difficult thing to do.  The Bath researchers discovered that combining two mirror-image chemical forms of xylose results in a stronger and more adaptable material.  They have filed a patent for their technology and are seeking industrial collaborators for further development.

The reliance of plastics and polymers on fossil fuels is a major problem.  Bio-derived polymers, such as this new one, are an important part of the effort to make plastics sustainable.

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Scientists make sustainable polymer from sugars in wood

Photo, posted January 25, 2017, courtesy of Keith Double via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Replacing Plastic Tableware | Earth Wise

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Plastics have been described as the “ubiquitous workhorse material of the modern economy.”  But their versatility, pliability, and durability comes at a heavy price to the environment.  Plastic pollution is quite literally everywhere.  Plastic debris and microplastic particles can be found in every corner of the globe, including the Arctic and Antarctic. 

The scourge of plastic pollution is driving scientists to create ecologically-friendly alternatives.  According to a paper recently published in the journal Matter, scientists have developed “green” tableware made from sugarcane and bamboo that doesn’t sacrifice on convenience or functionality.  This eco-friendly tableware could serve as a permanent replacement for plastic cups and other disposable plastic containers. 

Traditional plastic polymers, a product of petroleum, can take as long as 1,000 years to decompose in landfills.  The new material only takes 60 days to break down.

To create this material, scientists used bamboo and bagasse, also known as sugarcane pulp.  Bagasse is one of the largest food-industry waste products.  The researchers wound the fibers together to form a mechanically stable and biodegradable material.  They added an alkyl ketene dimer, an eco-friendly chemical, to increase the oil and water resistance of the material.  The green material is durable enough to hold liquids like hot coffee and hot greasy foods like pizza.   

There’s another advantage: the green material’s manufacturing process emits 97% less CO2 than the process to make commercial plastic containers.  The next step is to lower the manufacturing cost.  While the cost of cups made from the green material is $2,333 per ton, traditional cups made from plastic are still slightly cheaper at $2,177 per ton.

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This tableware made from sugarcane and bamboo breaks down in 60 days

Photo, posted May 19, 2013, courtesy of Henry Burrows via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A New Super-Enzyme For Breaking Down Plastic | Earth Wise

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The problems caused by plastic waste continue to grow.  Plastic pollution is everywhere, from the Arctic to the depths of the ocean.  We consume microplastics in our food and breathe them in the air.  It is very difficult to break down plastic bottles into their chemical constituents in order to make new ones from old ones. Therefore, we continue to produce billions of single-use plastic bottles, creating more and more new plastic from oil each year. 

Scientists at the University of Portsmouth in the UK have developed a new super-enzyme that degrades plastic bottles six times faster than before.  They believe that the new enzyme could be used for plastic recycling within a year or two.

The super-enzyme was derived from bacteria that naturally have the ability to eat plastic.  The researchers engineered it by linking two separate enzymes, both of which were found in a plastic-eating bug discovered in a Japanese waste site in 2016.  They revealed an engineered version of the first enzyme in 2018, which started breaking down plastic in a few days.  They had the idea that connecting two enzymes together would speed up the breakdown of plastic.  Such linkage could not happen naturally in a bacterium. 

Carbios, a French company, announced a different enzyme in April that can degrade plastic bottles within 10 hours but requires heating above 160 degrees Fahrenheit.  The new super-enzyme works at room temperature.

The team is now examining how the enzymes can be tweaked to make them work even faster.  Meanwhile, they plan to work in partnership with companies like Carbios, to bring super-enzymes for breaking down plastics into commercial use.

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New Super-Enzyme Can Break Down Plastic at Rapid Pace

Photo, posted March 24, 2017, courtesy of the USFWS – Pacific Region via Flickr. Photo credit: Holly Richards/USFWS.

Earth Wise is a production of WAMC Northeast Public Radio.

More Bugs That Eat Plastic | Earth Wise

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The world continues to struggle with the proliferation of plastic that is polluting the environment.  The Great Pacific Garbage Patch has now grown so large that it has spread across an area four times the size of California.  But there is no silver bullet in the struggle to reduce plastic pollution.  Reducing the use of plastic is probably the most viable approach, but increased recycling, the use of bioplastics, and various other strategies must play a role.

The essence of the problem is that plastic takes from decades to hundreds of years to decompose naturally.  The world produces billions of tons of plastic waste each year and less than 10% of it is recycled.  As a result, researchers around the world seek ways to safely and economically accelerate the decomposition of plastics.

A research team at Andong National University in South Korea has discovered the larvae of a particular species of darkling beetle can decompose polystyrene, which is one of the trickiest plastics to break down.  There are thousands of species of darkling beetles found in different habitats all over the world.  The one they identified is indigenous to East Asia.

The beetle larvae can consume polystyrene and reduce both its mass and molecular weight.  Furthermore, they found that the bacteria in the gut of the larvae could oxidize and change the surface property of polystyrene.  The handful of bacterial strains they identified were not like those of earlier insects found to degrade polystyrene.  As result, the researchers are hopeful that it may be possible to break down the plastic using other insects that feed on rotten wood.  Apart from the insects themselves, using just the bacterial strains found in the darkling beetles may prove to be an effective method for decomposing polystyrene.

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A New Species of Darkling Beetle Larvae That Degrade Plastic

Photo courtesy of Flickr.

I farmaci a base di erbe e omeopatici rappresentano una percentuale significativa (circa una confezione su otto) dell’assortimento da banco delle farmacie. Nel 2017, i farmaci a base di erbe hanno registrato vendite per 1,48 milioni di euro e 120 milioni di confezioni, mentre maschioforte.com i farmaci omeopatici hanno registrato vendite per 630 milioni di euro e 52 milioni di confezioni, secondo l’Associazione federale dell’industria farmaceutica (Bundesverband der Pharmazeutischen Industrie – BPI).

Earth Wise is a production of WAMC Northeast Public Radio.

Finding Plastic In Seafood | Earth Wise

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Researchers from the University of Exeter in the UK and the University of Queensland in Australia have developed a new method for identifying and measuring the presence of five different types of plastic in seafood.

The researchers purchased oysters, prawns, squid, crabs, and sardines from a market in Australia and analyzed them using the new technique.  They found plastic in every single sample.

Their findings showed that the amount of plastics present varies greatly among species and differs between individuals of the same species.  The measured plastic levels were 0.04 mg per gram of seafood in squid, 0.07 mg in prawns, 0.1 mg in oysters, 0.3 mg in crabs, and 2.9 mg in sardines. 

All the plastics are types commonly used in plastic packaging and synthetic textiles and are increasingly found in marine litter:  polystyrene, polyethylene, polyvinyl chloride, polypropylene, and polymethyl methacrylate.

The new method treats the seafood tissues with chemicals that dissolve the plastics present within them.  The resulting solution is then analyzed using a highly sensitive technique called Pyrolysis Gas Chromatography Mass Spectrometry which both identifies and quantifies the plastics.

Microplastics are an increasing source of pollution for much of the planet, including the oceans where they are eaten by all types of marine creatures ranging from planktonic organisms to large mammals.  Microplastics enter our diet not only from seafood, but also from bottled water, sea salt, beer, and honey, as well as from dust that settles on our food.

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Seafood study finds plastic in all samples

Photo, posted June 23, 2007, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Sustainable Flip-Flops | Earth Wise

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Flip-flops are the world’s most popular shoe.  They are lightweight, comfortable, affordable, and durable.  In fact, the global market for flip-flops is expected to reach a whopping $23.8 billion by the year 2025. 

But the popularity comes with a price.  Flip-flops account for a troubling percentage of plastic waste that ends up in our landfills and oceans.  As a result, demand for alternatives is compelling researchers to develop more sustainable versions of the popular footwear.

Scientists at the University of California San Diego have spent years working on this issue, and recently announced a breakthrough.  According to a study recently published in Bioresource Technology Reports, the research team has formulated polyurethane foams – made from algae oil – to meet commercial specifications for mid-sole shoes and the foot-bed of flip-flops.   In other words, the scientists have created sustainable, biodegradable, and consumer-ready materials that could replace plastics in some footwear. 

The UC San Diego scientists collaborated with Algenesis Materials – a technology startup – on the research.  Together, they worked to not only create the shoes, but to degrade them as well.  The team tested their customized foams by immersing them in traditional compost and soil.  The algae-based materials degraded after just 16 weeks.  

The life of any material should be proportionate to the life of the product.  The researchers point out that it doesn’t make sense to create a product that will last 500 years if it’ll only be used for a year or two. 

The research team is currently working on production details with its manufacturing partners.  The creation of biodegradable flip-flops that meet commercial footwear standards could eliminate tons of plastic waste from the environment.   

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New science behind algae-based flip-flops

Flip Flops Market Size Worth $23.8 Billion by 2025

Photo, posted December 12, 2019, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Recycling Tough Plastics | Earth Wise

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Thermoset plastics are ones that contain polymers that cross-link together during the curing process to form an irreversible chemical bond.  This improves the material’s mechanical properties, provides chemical resistance, heat resistance, and structural integrity.  Thermosets include epoxies, polyurethanes, and rubber used for tires.  The big problem with thermosets is that they cannot be easily recycled or broken down after use.

Seventy-five percent of all plastics are thermoplastics, which can be recycled by heating them until they become liquid and can then be remolded.   Thermoset plastics, on the other hand, have such strong chemical bonds that they simply will not melt.  They will typically burn before they can be remolded.

Chemists at MIT have recently developed a way to modify thermoset plastics with a chemical linker that makes them much easier to break down, but still retain the mechanical properties that make them so useful.

In a study published in Nature, the researchers produced a degradable version of a thermoset plastic called pDCPD.  They then broke the plastic down into a powder and were able to use the powder to create more pDCPD.  The paper also proposed a theoretical model that suggests that their approach could be used for a wide range of other plastics and polymers, including rubber.

By adding a chemical called a silyl ether monomer to the liquid precursors that from pDCPD plastic, they found that the resultant material retained its mechanical strength but can be broken down into a soluble powder upon exposure to fluoride ions.

Using this approach with other thermoset materials, the researchers believe it will be possible to create recyclable versions of many of the toughest plastic materials.

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Chemists make tough plastics recyclable

Photo, posted September 1, 2019, courtesy of Luke McKernan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

WAMC Northeast Public Radio

WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)