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Harmful algal blooms and climate change

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An algal bloom is a rapid increase in the density of algae in an aquatic system.  Harmful algal blooms occur when bodies of water get overloaded with nitrogen and phosphorus runoff from agriculture and other human activities. These excess nutrients can facilitate the out-of-control growth of cyanobacteria, also known as blue-green algae. 

Some species of blue-green algae produce a toxin called microcystin.  These toxins pose a serious health hazard to people, animals, and the environment.  Microcystin affects liver function and can cause death in animals, as well as humans in rare instances.  A notable incident occurred in the summer of 2014, when cyanobacteria contamination in Lake Erie left 500,000 residents in Ohio and Michigan without water for 72 hours and sickened more than 100 people. 

According to a study led by researchers from Carnegie Science, as climate change warms the earth, higher-latitude regions will be at a greater risk for microcystin produced by algal blooms.  The study found water temperatures of 68 to 77 degrees Fahrenheit as being at the greatest risk for developing dangerous levels of microcystin. 

In the study, which was published in the journal Nature Water, the research team also demonstrated that the areas most susceptible to high toxin concentrations will continue to move northward. And in some areas, researchers say the relative risk of exceeding water quality guidelines will increase by up to 50% in the coming decades.

The research team hopes its findings raise more awareness about water sustainability, and the need to focus on the quality of the water as much as the quantity of water. 

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Geographic redistribution of microcystin hotspots in response to climate warming

Photo, posted October 27, 2010, courtesy of Nara Souza / Florida Fish and Wildlife Commission via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Forest-based agroforestry

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Tree plantings have become a go-to climate solution for governments and conservation groups due to the carbon-storing potential of trees.  While planting new trees on open farmland would help capture additional carbon, a new study led by scientists from Yale School of the Environment suggests a powerful alternative: forest-based agroforestry.

Instead of clearing land for crops or starting fresh with new trees, forest-based agroforestry (or FAF) brings agriculture into existing forests.  Think fruits, nuts, and medicinal plants, for example, grown sustainably under a forest canopy – all while maintaining biodiversity and storing carbon.

According to the researchers, human activity in forests is often seen as harmful. But for thousands of years, Indigenous and local communities have managed forests in ways that actually strengthen them.

The study, which was recently published in the journal Nature Climate Change, found that FAF not only rivals tree planting in terms of climate benefits, but it can also generate income and support cultural practices tied to the land.

Despite these benefits, forest-based agroforestry receives far less funding and policy support due to two key misconceptions. It’s frequently confused with industrial systems focused on global commodity crops, and results from tropical regions are wrongly assumed to apply to temperate and boreal forests.

The researchers recommend including FAF in agroforestry policies, clearly distinguishing it from harmful industrial practices, and expanding research on FAF in temperate and boreal regions to guide better land management.

Forest-based agroforestry appears to be a natural climate solution hiding in plain sight.

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Agriculture in Forests Can Provide Climate and Economic Dividends

Photo, posted May 8, 2023, courtesy of Preston Keres / USDA Forest Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Plastic from food waste

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Plastic waste management is a complicated business.  Most methods of recycling or breaking down plastic are costly and harmful to the environment.  The most common biodegradable alternatives – like paper straws – are less than ideal replacements.

There are many approaches to creating biodegradable plastics using feedstocks like seaweed, sugarcane, and other plant matter.  However, the resulting plastics often fall short compared with conventional petroleum-based plastics.

One type of bioplastic that is gaining popularity is polyhydroxyalkanoates, or PHA.  PHA is a plastic produced by microorganisms.  It is fully compostable or biodegradable but in other ways but looks, feels, and functions like regular plastic but without the environmental drawbacks.

PHA can be made using bacterial fermentation of a variety of feedstocks such as vegetable oils, sugars, starches, and even methane and wastewater.

Researchers at a startup from the University of Waterloo in Canada called MetaCycler BioInnovations have developed a process for producing PHA based on bacteria that has been engineered to convert waste from milk and cheese production.  This solution upcycles waste from the dairy industry into cost-effective, sustainable bio-based plastics. 

PHAs can be tailored to have a wide range of properties ranging from being rigid and tough to being quite flexible.  Therefore, they can be suitable for many applications including packaging, agricultural films, and consumer goods. 

The Waterloo technology is a way to tackle the problems of both food waste and plastic pollution with one solution.

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Turning food waste into a new bioplastic

Photo, posted December 10, 2017, courtesy of Leonard J Matthews via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Fighting harmful algal blooms with harmful algal blooms

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Harmful algal blooms – HABs – occur when colonies of algae grow out of control and produce toxic or harmful effects on people, marine life, and birds.  HABs occur naturally but their frequency and intensity are often associated with increased nutrient loading (mainly phosphorous and nitrogen) in bodies of water that is the result of runoff from sources like lawncare and agriculture.

Researchers at Florida Atlantic University have developed a technique for transforming cyanobacteria – also known as blue-green algae and a prime HAB material – into an effective material for removing phosphorous from water.

Their process converts blue-green algal biomass – essentially hazardous waste – into a custom-made adsorbent material that can pull harmful phosphorous from water.  The algae is first quickly heated up using microwaves and then it is modified by adding lanthanum chloride. 

The study took blue-green algae from Florida’s Lake Okeechobee, synthesized the adsorbent material in minutes, and using only small amounts of it could remove 90% of the phosphorous present in only half an hour.  It worked perfectly well in the presence of natural organic matter.  Using the harmful algae itself to prevent algal growth in bodies of water is an innovative way to reduce its further occurrence.

Phosphorous is a major contributor to the occurrence of harmful algal blooms, which can lead to toxic water conditions, loss of aquatic life, and significant economic losses for the fishing and tourism industries.  This technique could prove to be an essential tool for managing the growing problem of nutrient pollution.

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FAU Engineering Develops New Weapon Against Harmful Algal Blooms

Photo, posted October 27, 2010, courtesy of Jennifer L. Graham / U.S. Geological Survey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Politics and plastic

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The world currently produces nearly half a billion tons of plastic each year.  This is more than twice the amount it produced 20 years ago.  Half of all plastics ever manufactured have been made in the past 20 years.  Plastic waste is everywhere.  About eight million tons of plastic waste escapes into the ocean each year.

Environmental groups have urged nations to adopt a legally binding treaty to address the ever-growing problem of plastic pollution. The United Nations climate conference in South Korea last month took up the issue of reaching agreement on such a treaty.  At what was supposed to be the final round of talks on the topic, delegates could not bridge wide differences on what such a treaty should contain.

The main bone of contention was whether the treaty should include limits on plastic production itself.  Saudi Arabia, Russia, Kuwait, and other oil-producing countries opposed any curbs on plastic production.   They also opposed the phase-out of harmful chemicals used in the production of plastic.

The Saudi delegation claimed that if the issue of plastic pollution is addressed, there should be no problem with producing plastics.  They said the problem is pollution itself, not plastics.  They proposed a focus on improving recycling and waste management.

Of course, preventing plastic pollution from occurring is an extremely challenging thing to do.  Delegates from countries pushing for a wide-ranging treaty – led by Rwanda – were unwilling to accept a toothless theory lacking real constraints on the plastics industry.

As the conference ended, delegates said that they would reconvene in future months to try again to produce a treaty.  No date or place has been announced.

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Nations Fail to Reach an Agreement on Plastic Pollution

Photo, posted February 4, 2023, courtesy of Ingrid Taylar via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A better way to extract lithium

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Lithium is the critical component in the batteries that power phones and computers, electric cars, and the systems that store energy generated by solar and wind farms.  Lithium is not particularly rare, but it is difficult and often environmentally harmful to extract from where it is found.

Traditional ore sources are increasingly difficult and expensive to mine.  The largest known deposits of lithium are in natural brines – the salty water found in geothermal environments.  These brines also contain other ions like sodium, potassium, magnesium, and calcium, and efficiently separating out the lithium is extremely challenging.

Traditional separation techniques consume large amounts of energy and produce chemical waste, particularly hazardous chlorine gas.  These techniques typically suffer from poor selectivity; that is, the process is interfered with by the other ions present in natural brines.

A team of researchers at Rice University has developed a three-chamber electrochemical reactor that improves the selectivity and efficiency of lithium extraction from brines.  The middle chamber of the reactor contains a specialized membrane that acts as a barrier to chloride ions, preventing them from getting to the electrode area where they can form chlorine gas.

The new reactor has achieved a lithium purity rate of 97.5%, which means the setup can effectively separate lithium from other ions in the brine and allow the production of high-quality lithium hydroxide, the key material for battery manufacturing. 

The Rice University reactor design has the potential to be a game changer for lithium extraction from geothermal brines.

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‘Game changer’ in lithium extraction: Rice researchers develop novel electrochemical reactor

Photo, posted October 21, 2023, courtesy of Simaron via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Progress towards electric school buses

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The U.S. has nearly half a million school buses providing daily transportation for about 20 million students.  Most of these buses are powered by diesel engines which not only dump greenhouse gases into the atmosphere but also fill kids’ lungs with harmful fumes.

Thanks to various federal and state incentive programs, this situation is starting to change.  School districts all over the country are beginning to swap out old diesel buses for emissions-free electric-powered school buses.

Electric school buses are finding their way into school districts of all sizes and demographics.  The first district in the country to go fully electric was in Martinsville, Texas, which last year converted its 4-bus fleet.  The first large urban district to go all-electric was the 74-bus fleet in Oakland, California this summer.

The EPA’s $5 billion Clean School Bus program and many state initiatives are providing incentives for the transition.  Five years ago, there were less than 1,000 electric school buses in the U.S.  Now there are about 5,000 and more than 7,000 additional buses are in the pipeline.

Apart from the climate implications, there is urgency to replacing diesel school buses from a health perspective.  Diesel exhaust is classified as a carcinogen by the World Health Organization, and it contains fine particles and nitrogen oxides, both of which are well-documented asthma triggers.

Electric buses are more expensive than diesel buses, but they are much cheaper to operate. School districts need to put in place charging infrastructure.  The transition is not so easy to accomplish, but it is an important step, and more and more school districts are taking it.

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Slowly but Surely, U.S. School Buses Are Starting to Electrify

Photo, posted May 5, 2021, courtesy of California Energy Commission via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Megafires and orchard health

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The frequent and massive megafires in places like Canada and the American west have led to a lot of research on the impact of smoke on humans but there has been less study of the effects of smoke on plant health.  Researchers at the University of California, Davis have found that trees are just as vulnerable as humans are to the harmful effects of long-term exposure to smoke.

The Davis researchers studied almond, pistachio, and walnut trees at 467 orchard sites in California’s Central Valley from 2018 to 2022.  In 2022, so-called megafires burned more than 4.2 million acres in California, pouring ash and smoke into the sky.  The researchers had been studying how trees store carbohydrates to cope with heat and drought. 

With the onset of the fires, they saw an opportunity to study how smoke affects carbohydrate levels.  Trees use stored carbohydrates to sustain them through winter dormancy and spring growth.  Trees produce carbohydrates via photosynthesis and thick smoke blocks the amount of light reaching the trees.  Beyond that, there are other aspects of wildfire smoke, such as particulate matter and ozone that appear to affect photosynthesis.

The team found that the smoke not only reduced the amount of carbohydrates in trees but also caused losses that continued even after the fires were extinguished.  This led to nut yield decreases of 15% up to 50% in some orchards.  The researchers expected to see some impact on the trees during periods when smoke was really dense but were not expecting the smoke to have such a lingering effect and result in a significant drop in yield.

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Smoke From Megafires Puts Orchard Trees at Risk

Photo, posted October 1, 2008, courtesy of Suzi Rosenberg via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Greenhouses and the environment

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The use of greenhouses around the world has been growing dramatically.  A new satellite mapping exercise estimated the total land area covered with permanent greenhouses at 3.2 million acres, which is an area the size of Connecticut.  More than half of this is in China, where the growth of greenhouses has been driven by the rapid urbanization of the country and by a more prosperous population increasingly consuming produce like tomatoes, cucumbers, peppers, and eggplants.

The intensive agricultural methods employed within greenhouses can be harmful to local environments because of overtaxing water supplies and by polluting rivers and soils with nutrients, pesticides, and plastic waste.  But the effects of vast areas of plastic coverings on local temperatures can be even more dramatic, and often beneficial.

There are so many plastic and glass roofs in many areas that they are reflecting sufficient amounts of solar radiation to cool local temperatures.  Greenhouse roofs increase the albedo – the reflectivity – of the land surface typically by a tenth.

All these greenhouses are just the tip of the albedo iceberg.  Many farms now temporarily cover crops with reflective plastic sheets.  If these coverings are included in the satellite survey, the total reflective area would be about ten times greater – roughly the size of New York State.

A study in Almeria, on the Mediterranean coast of Spain, which grows about 3 million tons of fruit and vegetables annually, determined the cooling effects of greenhouses.  Weather stations amid the greenhouses showed an average cooling of 1.3 degrees Fahrenheit compared with the surrounding area.

Greenhouses are an accidental and benign form of climate engineering. The cooling provided by greenhouses is similar to the effect of white roofs in urban areas. 

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Could the Global Boom in Greenhouses Help Cool the Planet?

Photo, posted September 6, 2017, courtesy of Lance Cheung / USDA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Forever chemicals in water

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So-called forever chemicals are pervasive in a wide range of products.  These are man-made substances called per- and polyfluoroalkyls or PFAS.  They get their unfortunate nickname because the chemical bonds in them are so strong that the compounds don’t break down for hundreds or even thousands of years.

PFAS compounds are used in makeup, dental floss, nonstick pans, food wrappers, pesticides, stain-resistant fabrics and carpets, firefighting foams, and more.  High level exposure to some of these chemicals has been linked to a variety of health problems include high cholesterol, liver and immune system damage, pregnancy problems, and kidney and testicular cancer.

A recent study published in the journal Nature Geoscience has found that PFAS chemicals are showing up in water around the world.  The study looked at more than 45,000 water samples and found that about 31% of ground water tested that wasn’t even near any obvious source of PFAS contamination had levels of the chemicals that are considered harmful to human health by the EPA.  About 16% of surface water samples – streams, rivers, ponds, and lakes – also not near any known source, had similar hazardous PFAS levels.

The EPA has now imposed strict new drinking water limits for six types of PFAS.  Going forward, water systems are required to monitor for these chemicals and remove them if they are found above allowable levels.  The new rules make the United States one of the strictest countries in the world in terms of regulating PFAS in water.

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EPA puts limits on ‘forever chemicals’ in drinking water

Photo, posted May 5, 2020, courtesy of Brandon Shaw via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The slow decline of coal

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Despite the fact that coal is the dirtiest and most climate-harmful energy source we have, the global demand for it hit a record high in 2023. The demand for coal grew by 1.4% worldwide, according to an analysis by the International Energy Agency.

Coal use grew by 5% in China and 8% in India.  The two countries are the world’s largest producers and consumers of coal.  Meanwhile, coal use in the U.S. and the European Union fell by 20%.

Despite this discouraging news, the IEA forecasts that coal use will decline over the next two years.  There have been declines in coal demand a few times before, but they were driven by unusual events such as the collapse of the Soviet Union and the Covid-19 crisis.  But the IEA says that the forthcoming decline is different.  It will be driven by the formidable and sustained expansion of clean energy technologies.

According to the IEA, global coal demand will fall by 2.3% by 2026 even in the absence of new policies to curb coal use.  Forces at play will be increased hydropower in China as it recovers from drought and puts new wind and solar projects online.  China is responsible for more than half of global coal demand, but it is also responsible for more than half of the planned renewable power projects coming online over the next three years.  Experts believe that with these forthcoming projects, Chinese emissions may have peaked in 2023.

The projected drop in coal demand is still far short of what is required for the world to avoid catastrophic warming.  Much greater efforts are needed to meet international climate targets.

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After a Record 2023, Coal Headed for Decline, Analysts Say

Photo, posted August 25, 2015, courtesy of Jeremy Buckingham via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Banning Neonicotinoid Pesticides | Earth Wise

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New York’s Birds and Bees Protection Act contains a targeted restriction on neonicotinoid pesticides. These widely-used insecticides are absorbed by plants and can be present in pollen and nectar, making them toxic to bees and other pollinators.

Among the largest applications of neonics (as they are called) has been in the form of coatings on crop seeds, such as corn and soybeans.  In 2019, Canada’s Quebec province strongly limited neonic use to protect pollinators and the environment.  The chemical industry vigorously protested the regulations and claimed that the restrictions would cause the collapse of the grain sector in Quebec.

Seed suppliers began supplying uncoated seeds in 2019 and now there is scarcely any use of coated seeds in the province.  Monitoring of over 1,000 agricultural sites has shown that there have been no crop failures related to the pesticide restrictions.  In fact, use of the neonics had no economic benefits. 

Naysayers warned that even more harmful pesticides or other farming practices would be used instead.  But that hasn’t happened either. Some farmers switched to much safer insecticides and others abandoned insecticide treatments altogether.

New York has faced similar opposition by farmers and chemical manufacturers to the Birds and Bees Protection Act and all of the same arguments that have been proven to be invalid in Quebec are being made in New York.  Most major environmental advocates in the state support the measures embodied in the legislation.  As usual, it boils down to a battle between economic interests and the health of the environment.

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Québec’s experience with pesticide ban offers a glimpse of what New York can expect

Photo, posted August 29, 2013, courtesy of the United Soybean Board / the Soybean Checkoff via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Paper Cups Are Not So Great | Earth Wise

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The environmental cost of plastic waste is a highly visible global issue.  The response has been a growing effort to replace plastic items with alternative materials.  One very visible change of this sort has been the replacement of plastic cups with paper cups at coffee shops.  But a new study at the University of Gothenburg in Sweden has found that this solution has problems of its own.

Researchers studied the effects of disposable cups in the environment on the larvae of the butterfly mosquito.  They placed disposable cups made from different materials in wet sediment and water for a few days and observed how the chemicals leached from the cups affected the growth of the larvae.  It turned out that all of the different kinds of cups had negative effects.  The concern is not specifically about mosquito larvae; it is the fact that more environmentally friendly drinking cups are still potentially harmful to living things.

Paper is neither fat nor water resistant, so paper cups need to be treated with a surface coating.  The most common coating is polylactide, which is a type of bioplastic.  It is generally considered to be biodegradable, but the study shows that it can still be toxic.  Bioplastics still contain many different chemicals and the potential toxicity of each of them is not well known.

The UN is trying to develop a binding agreement by the world’s countries to end the spread of plastics in society and nature.  For such an agreement to be effective, the plastics industry will need to clearly report what chemicals all products contain, including such mostly invisible products as the coating on paper drinking cups.

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Paper cups are just as toxic as plastic cups

Photo, posted October 23, 2016, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Cost Of Invasive Species | Earth Wise

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According to a new report published by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services for the United Nations, invasive species introduced to new ecosystems around the world are causing more than $423 billion in estimated losses to the global economy every year.  These economic costs are incurred by harming nature, damaging food systems, and threatening human health.

According to the report, these costs have at least quadrupled every decade since 1970 and the estimates are actually conservative because it’s difficult to account for all of the effects of invasive species.

The report estimates that humans have intentionally or unintentionally introduced more than 37,000 species to places outside their natural ranges.  More than 3,500 of them are considered invasive because they are harmful to their new ecosystems.  Invasive nonnative species were a major factor in 60% of known extinctions of plants and animals.

Some species are relocated deliberately by the wildlife trade and international shipping.  Other plants and animals end up hitching a ride with ordinary travelers as they move about by car, boat, plane, or train. 

Invasions can damage human health.  Mosquitos that transmit diseases like malaria, dengue fever, and the Zika virus have become invasive around the world. The wildfires in Hawaii this summer were fueled by invasive nonnative grasses in a warming climate. 

Nearly every country in the world has agreed to participate in a sweeping agreement to preserve biodiversity and reduce invasive species.  It is an essential global goal.

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Invasive Species Are Costing the Global Economy Billions, Study Finds

Photo, posted June 2, 2022, courtesy of Sam Stukel (USFWS) via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Rare Earths And The Energy Transition | Earth Wise

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Limiting the rise in global temperature to no more than 1.5 degrees Celsius requires decarbonization.  This means slashing fossil fuel use, switching to renewable energy sources, and electrifying as many sectors of the economy as possible.  Doing these things requires huge numbers of wind turbines, solar panels, electric vehicles, and storage batteries.   All of them use rare earth elements and other critical metals.

The 17 rare earth elements are actually common, but they are called rare because they are seldom found in sufficient quantities to be extracted easily or economically. 

China once supplied 97% of the world’s rare earth elements as a result of government support, cheap labor, lax environmental regulations, and low prices.  Once the world started to realize the dangers of being so dependent on China, many countries began developing their own rare earth element production. (However, today China still produces 60-70% of the world’s rare earth elements).

It is difficult to mine rare earth elements without causing environmental damage.  The prevalent extraction techniques involve toxic chemicals that can leach into the environment and, because rare earths are often found near radioactive elements, mining often brings dangerous radioactive waste into the environment.

Researchers are working on ways to make rare earth mining more sustainable.  Some of these include biomining – which uses microbes to extract rare earths from ores, electrical methods to free rare earths from ores, and so-called agromining, which is growing plants that hyperaccumulate rare earths from the soil into their tissues.

Making rare earth mining more sustainable and less harmful to the environment is an essential part of the world’s future.

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The Energy Transition Will Need More Rare Earth Elements. Can We Secure Them Sustainably?

Photo, posted November 18, 2008, courtesy of the Oregon Department of Transportation via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Better Zinc Batteries | Earth Wise

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The rapid growth of wind and solar power continues to drive a global quest for new battery technologies that can be used to store the energy generated by these sources when the sun isn’t shining, and the wind isn’t blowing.

For the most part, current battery energy storage systems use lithium-ion batteries – the same sort of batteries found in cellphones and electric vehicles.  There are many other battery chemistries, but they mostly have shortcomings in performance, economy, or longevity. 

Batteries store electricity in the form of chemical energy and chemical reactions convert that energy into electrical energy. Every battery has two electrodes:  the anode, from which electrons flow into external circuits, and the cathode, which receives electrons from the external circuit.  The electrolyte is the chemical medium through which the electrons flow.

One technology that has great potential is zinc-based batteries.  Zinc itself is a metal that is safe and abundant.  Batteries based on it are energy dense. However, zinc batteries have faced the challenge of having a short cycle life.  The batteries end up plating zinc on their anodes and battery performance degrades. 

A team of researchers at Oregon State University and three other universities have recently developed a new electrolyte for zinc batteries that raises the efficiency of the zinc metal anode to nearly 100% – actually slightly better than lithium-ion batteries.

Zinc batteries have a number of potential advantages over lithium-ion.  The new hybrid electrolyte developed by the researchers is non-flammable, cost-effective, and has low environmental impact.  Lithium-ion batteries rely on the supplies of relatively rare metals that are often difficult and environmentally harmful to obtain. 

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Researchers develop electrolyte enabling high efficiency of safe, sustainable zinc batteries

Photo, posted May 13, 2017, courtesy of Jeanne Menjoulet via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Fuel From Coffee Grounds | Earth Wise

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The world drinks a lot of coffee.  Americans alone consume 400 million cups a day.  Each cup of coffee results in about half an ounce of coffee grounds.  Adding that up, this country produces over 6,000 tons of coffee grounds each day.  While coffee grounds are not particularly harmful, that is an awful lot of waste that mostly ends up in landfills or is incinerated.

Researchers at Aston University in the UK have developed a method of producing high-quality biodiesel fuel from coffee grounds.  Their study was published in the journal Renewable and Sustainable Energy Reviews.

The technique consists of growing a particular species of microalgae (Chlorella vulgaris) directly on spent coffee grounds.  The coffee grounds provide both the nutrients for the microalgae and a structure upon which it can grow.   Exposing the algae to light for 20 hours a day and dark for just four hours a day produced the best quality biodiesel.

Microalgae is well-known as a feedstock for biodiesel production.  Previously, it has been grown on materials like polyurethane foam or nylon which don’t provide any nutrients.   Using the coffee grounds as the substrate for growth means that no external nutrients are needed.

The resultant enhanced biodiesel produces minimal emissions and good engine performance and meets both US and European specifications.  This feedstock for producing biodiesel is ideal since it doesn’t require any competition with food crops and instead makes use of a widely available waste product.  The hope is that it may reduce the cutting down of palm trees to extract oil for biofuel.  In southeast Asia, this has been a major source of deforestation and increased greenhouse gas emissions.

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Aston University researchers ‘feed’ leftover coffee grounds to microalgae to produce low emission biodiesel

Photo, posted October 13, 2007, courtesy of David Joyce via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Cleaning Up Forever Chemicals | Earth Wise

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PFAS, per- and polyfluoroalkyl substances, are chemical pollutants that threaten human health and ecosystem sustainability.  They are used in a wide range of applications including food wrappers and packaging, dental floss, firefighting foam, nonstick cookware, textiles, and electronics.  Over decades, these manufactured chemicals have leached into our soil, air, and water.  Chemical bonds in PFAS molecules are some of the strongest known, so the substances do not degrade easily in the environment.

Studies have shown that at certain levels, PFAS chemicals can be harmful to humans and wildlife and have been associated with a wide variety of health problems.

Currently, the primary way to dispose of PFAS chemicals is to burn them, which is an expensive multistep process.  Even trace levels are toxic, so when they occur in water in low amounts, they need to be concentrated in order to be destroyed.

Researchers at Texas A&M University have developed a novel bioremediation technology for cleaning up PFAS.  It uses a plant-derived material to absorb the PFAS which is then eliminated by microbial fungi that literally eat the forever chemicals.

The sustainable plant material serves as a framework to adsorb the PFAS.  That material containing the adsorbed PFAS serves as food for the fungus.  Once the fungus has eaten it, the PFAS is gone. 

The EPA has established a nationwide program to monitor the occurrence and levels of PFAS in public water systems and is considering adding PFAS threshold levels to drinking water standards.  If this happens, the technology developed at Texas A&M may become an essential part of municipal water systems.

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Texas A&M AgriLife develops new bioremediation material to clean up ‘forever chemicals’

Photo, posted August 10, 2013, courtesy of Mike Mozart via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Lake Tuz Is Disappearing | Earth Wise

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Lake Tuz is Turkey’s second-largest lake and one of the world’s largest hypersaline lakes.  Its high salt content makes it an ideal breeding ground for some migratory bird species, including flamingos, which are often present there in huge numbers in the spring and summer.

Now, Lake Tuz rarely spans an area much larger than a puddle. In some summers, it completely dries up.  It did so this past summer, which resulted in the deaths of thousands of flamingos.

According to experts, Lake Tuz is a victim of climate change-induced drought, which has hit the region hard, and decades of harmful agricultural policies that exhausted the underground water supply.

Water in this region has become increasingly scarce.  The Mediterranean Basin has already seen more frequent and intense droughts, and is considered a climate change hotspot. 

According to new research, which was recently published in the journal Regional Environmental Change, Lake Tuz generally contained enough water in August for the lake to be considered permanent up until 2000.  But between 2001 and 2016, something shifted.  Water spanned less than 20% of the lake in every August except for one, and droughts became more frequent and intense. And in some years, the lake completely dried up.   

What caused this change?  According to the research team, Lake Tuz’s decline coincided with the excessive use of groundwater and surface water resources responsible for feeding the lake.  Some streams were rerouted for agricultural purposes, while others were dammed.  And when surface water sources dwindled, people turned to groundwater that historically fed the springs in Lake Tuz. 

Lake Tuz may be on the brink of extinction. 

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Impact of climate variability on the surface of Lake Tuz (Turkey), 1985–2016

Disappearing Lake Tuz

Photo, posted August 16, 2021, courtesy of Godot via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Reducing COVID-19 Spread With UV Light | Earth Wise

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New research published by the University of Colorado Boulder analyzes the effects of different wavelengths of ultraviolet light on the SARS-CoV-2 virus.   The research found that a specific wavelength of UV light is not only extremely effective at killing the virus that causes COVID-19, but also that this wavelength is safer for use in public spaces.

UV light is naturally emitted by the sun and most forms of it are harmful to living things – including microorganisms and viruses.   The most harmful UV radiation from the sun is filtered out by the atmosphere’s ozone layer.   Human-engineered UV light sources screen out harmful UV rays with a phosphorus coating on the inside of the tube lamps.  Hospitals and some other public spaces already use UV light technology to disinfect surfaces when people are not present.

The new research found that a specific wavelength of far-ultraviolet-C, at 222 nanometers, was particularly effective at killing SARS-CoV-2, but that wavelength is blocked by the very top layers of human skin and eyes.  In other words, that light has essentially no detrimental health effects for people while it is very capable of killing off viruses.

The researchers argue that this safe wavelength of Far UV-C light could serve as a key mitigation measure against the COVID-19 pandemic.  They imagine systems that could cycle on and off in indoor spaces to routinely clean the air and surfaces or perhaps create an ongoing, invisible barrier between teachers and students, customers and service workers, and other places where social distancing is not practical.  Installing these specialized UV lights would be much cheaper than upgrading entire HVAC systems in buildings.

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Specific UV light wavelength could offer low-cost, safe way to curb COVID-19 spread

Photo, posted January 18, 2008, courtesy of Phil Whitehouse via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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