Environmental Hazards, Science

Scientists Find New Way to Process Radioactive Waste

The question of what to do with radioactive waste may have been solved by a team of Japanese scientists.
The question of what to do with radioactive waste may have been solved by a team of Japanese scientists. Photo: Shutterstock

Ever since the first atomic bomb was exploded during World War II’s Manhattan Project, and ever since the first nuclear power plant opened in Obninsk, Russia, radioactive waste has been accumulating. As the number of nuclear power plants and nuclear weapon plants increased, the question of what to do with all that waste has become one of the biggest issues facing science today.

The primary issue is what to do with radioactive waste after the uranium and plutonium have been recovered from spent nuclear fuel using standard reprocessing methods such as Plutonium Uranium Redox Extraction (PUREX).

Up until now, the most viable option for disposal of nuclear waste has been burying it deep underground. Other solutions such as partitioning and transmuting, which involve separating nuclear fuel into minor actinides such as neptunium, americium, and curium, have proven to be costly and cumbersome because of the need to separate isotopes before they can undergo transmutation. But now, a team of researchers at Tokyo Institute of Technology may have come up with a solution to the radioactive waste problem.

The team discovered a method of dramatically reducing the effective half-life of long-lived fission products (LLFPs) such as selenium-79, zirconium-93, technetium-99, palladium-107, iodine-129, and caesium-135. That method involves transmuting these isotopes in fast-spectrum reactors, which don’t need isotope separation like other methods do.

By adding a moderator (slowing-down material) called Yttrium deuteride (YD2), the team found that LLFP transmutation efficiency increased in the radial blanket and shield regions of the reactor. The researchers say this increased effectiveness is due to the moderator’s ability “to soften the neutron spectrum leaking from the core.”

Using this method, the researchers say, the 17,000 tons of LLFPs in Japan could potentially be disposed of by using 10 fast spectrum reactors. This method also has the advantage of contributing to electricity generation and supporting efforts toward nuclear non-proliferation.

Although ultimately, the best solution to the nuclear waste problem is to invest in non-toxic energy sources like solar and wind power, it’s a good thing these researchers came up with a way to decrease the toxicity of radioactive waste and give its by-products a new life—and a much shorter half-life.

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carbon emissions, emissions, Science

Moving Bus Stops Could Reduce Pollution Exposure

Moving bus stops 120 feet from intersections can drastically reduce the amount of pollutants bus commuters are exposed to.
Passengers board an MTA bus in New York. Moving that stop away from the intersection could reduce the pollution to which transit commuters are exposed. Photo: Roman Tiraspolsky / Shutterstock.com

There’s no doubt that mass transit can make a huge difference in the overall air quality of cities. An increasing number of people are realizing that they can reduce their carbon footprint by riding a bus to and from work rather than being stuck in traffic in a car.

There’s just one problem with riding the bus, and that’s waiting for the bus.

Research has shown that in many cities in the United States and internationally, bus riders could spend 15 to 25 minutes each way waiting for a bus. This isn’t just a convenience issue; it’s a pollution exposure issue, too.

“The wait often means spending time in some of the most polluted locations in cities, close to intersections where cars, trucks, and buses are continually stopping and accelerating, spewing out high concentrations of noxious exhaust,” said Suzanne Paulson of UCLA, senior author of an article that appeared recently in the journal Environmental Pollution. “The exhaust contains gases and large amounts of ultrafine particles that are essentially unregulated by the Environmental Protection Agency because the EPA regulates fine particles by weight, and these particles weigh so little.”

The good news, according to the researchers, is that moving bus and light rail stops to locations 120 feet from intersections can significantly reduce the amount of pollutants to which bus commuters are exposed.

The researchers came to their conclusions by using a zero-emission vehicle equipped with instruments that measure ultrafine particles and tailpipe pollutants like carbon monoxide and nitrogen oxide. The studies were conducted in several neighborhoods in and around Los Angeles, over a 15-day period from summer into late fall in 2013 and over four days in the summer of 2014.

“We then combined and analyzed the data for each intersection to create high-resolution maps of pollutant concentrations along blocs,” said study lead author Wonsik Choi.

“Except in areas with minimal traffic, we always found there would be a significant reduction [of pollutants],” said Choi.

Traffic engineers believe that traffic flows better if bus stops are located after intersections rather than before. Better traffic flow can lead to less stop-and-go traffic, which would also improve air quality. The researchers caution that although moving the stops 120 feet from the end of a block will improve transit users’ pollution exposure, as long as that distance doesn’t put the bus stop in range of pollution from the next street.

Considering that most city blocks are about generally about 400 by 400 feet in size, it seems like it should be easy to move bus stops 120 feet away from intersections. That doesn’t mean buses won’t park all along a block where a stop is located, but it does mean that theoretically, passengers waiting for their bus will be able to do so in an area that exposes them to fewer pollutants.

Environmental Hazards, oceans

Keeping Plastic Out of Our Waters

Several nations and states are taking measures to prevent plastic pollution from reaching the oceans.
Plastic pollution in the ocean. Photo: Shutterstock

This past week Chile’s President Michelle Bachelet signed a bill that will ban plastic bags in more than 100 coastal areas. Her decision, she said, was about “taking care of our marine ecosystems.”

“Our fish are dying from plastics ingestion or strangulation; [limiting plastic bags] is a task in which everyone must collaborate,” she added.

It’s a huge deal, not only for Chile’s environment, but for other countries considering their own plastic bag ban.

Chile’s World Wildlife Fund noted that the bill “marks a very important milestone for Chile and opens the door for the whole country to say goodbye to plastic bags.”

According to a 2015 study published in Science, about eight million tons of plastic are dumped into the sea every year, which can affect millions of marine species. And toxins ingested by fish exposed to those plastics can affect humans as well when they eat those fish.

Chile’s potential ban on plastic bags isn’t the first such ban. The U.S. in particular has already instated bans in many areas, including Massachusetts, California, and Washington. They’ve been shown to be quite effective, too: The ban in San Jose, California led to an 89 percent reduction in plastic bags ending up in storm drains. And in Seattle, Washington, the plastic bag ban has led to a 50 percent reduction of plastic bags ending up in city dumps.

In other areas it’s been trickier. State Senator Linda Stewart of Orlando recently announced she will file a bill in Tallahassee to reverse the current law that prevents governments from banning plastic bags and Styrofoam containers.

Why would a city have such a law in place to begin with? Money, it seems: Grocery heavy-hitter Publix lobbied state politicians to the tune of $1 million to get the law against banning plastic bags instated. However, Stewart may be turning the (plastic) tides with her bill, if it’s passed. At the very least, it’s inspired a similar measure in the Florida House of Representatives.

Banning plastic bags in more places—both in the U.S. and elsewhere—is likely to be a huge boon to marine wildlife. But there’s still a lot of work to be done.

Nature, oceans

New Study Says Sea Animals Eat Plastic Because of Its Taste

A new study says that sea animals may like plastic because it tastes good.
These coral polyps are feeding–and most likely ingesting lots of microplastics in the process. Photo: Shutterstock

Scientists have long known that plastic in the oceans can mimic prey, causing huge problems for sea life. But what they didn’t know is that even corals eat plastic.

Corals don’t have eyes, and they don’t move from their location, so why would they eat plastic? Apparently because it tastes good, according to a recent study from Duke University.

This taste factor may also be true for other sea life. After all, anecdotal evidence suggests that our cats and dogs eat plastic because they like the taste and/or the texture, so why wouldn’t sea life have the same reaction?

Microplastics, tiny pieces of weathered plastic less than 5 millimeters in diameter, have been accumulating in the world’s oceans for 40 years or more, and now they’re ubiquitous in the marine environment. They don’t just pose threats to corals, they also pose a threat to foraging sea animals including birds, turtles, mammals, and invertebrates.

Because plastic is largely indigestible, it can lead to intestinal blockages, create a false sense of fullness, or reduce energy reserves in animals that eat it.

“About eight percent of the plastic that coral polyps in our study ingested was still stuck in their guts after 24 hours,” said study co-lead author Austin S. Allen, a Ph.D. student at Duke.

Plastics can also leach hundreds of chemical compounds into the bodies of the creatures that eat it and into the environment as well. The biological effects of most plastic compounds are unknown, but we do know that some have already been shown to cause harm. For example, phthalates are confirmed environmental estrogens and androgens—that is, hormones that affect sex determination.

“Corals in our experiments ate all types of plastics, but preferred unfouled microplastics by a threefold difference over microplastics covered in bacteria,” Allen said.

“When plastic comes from the factory, it has hundreds of chemical additives on it. Any one of these chemicals or a combination of them could be acting as a stimulant that makes plastic appealing to corals,” said Alexander C. Seymour, a GIS analyst at Duke, who co-led the study with Allen.

The researchers hope their findings will encourage more scientists to study the role taste plays in determining why marine animals ingest microplastics.

“Ultimately, the hope is that if we can manufacture plastic so it unintentionally tastes good to these animals, we might also be able to manufacture it so it intentionally tastes bad,” Seymour said. “That could significantly help reduce the threat these microplastics pose.”

Environmental Hazards, Science

Road Pricing Could Be the Most Effective Solution to Car Pollution

A researcher from the University of British Columbia has concluded that road pricing is the most effective traffic management strategy for reducing urban pollution.
Photo via Pixabay

Motor vehicles are a huge source of pollution in cities. For many years, governments have used traffic management strategies to try and reduce vehicle emissions—but few seem to have made as much of a difference as road pricing.

Road pricing is essentially a “pay per use” plan that levies charges such as road tolls, congestion charges, and charges designed to discourage the use of certain types of vehicles or fuel sources in order to reduce pollution and congestion within city limits.

University of British Columbia transportation expert and civil engineering professor Alexander Bigazzi reviewed 65 studies on traffic management strategies in Asia, Europe, and the Americas. He concluded that road pricing is the most effective strategy to reduce emissions and traffic.

Other traffic management strategies include speed enforcement programs, lane management (e.g., HOV lanes), road and congestion pricing, and trip reduction strategies such as telecommuting or ride sharing.

“The strategies with the best evidence of air quality improvements are area road/congestion pricing and low-emission zones,” Bigazzi said. “Other strategies have potential benefits, but there is less empirical evidence, either because the benefits are very small or because the benefits are offset by some other effect.”

Why are road pricing and low-emission zones so effective? A major reason is that they reduce the amount of driving. They also ease congestion and reduce emission rates. Low-emission zones also encourage people to buy cleaner vehicles.

Of course, road pricing has to be implemented on a pretty large scale in order to be effective. Cities can’t just implement road pricing on certain roads, because motorists would find other ways to get into the city where they are not faced with road pricing or low-emission zones.

“Hundreds of cities in Europe have congestion pricing or low-emission zones in their city centers and are enjoying improved traffic flow and air quality,” Bigazzi said. “These strategies haven’t been embraced in North America in the same way for a variety of reasons, but there are great potential benefits for cities here ready to embrace innovation.”

What do you think? Would you like to see cities use traffic management strategies like road pricing in order to reduce pollution, even if it meant less convenience for you? Do you think road pricing would work in your city? Please share your thoughts in the comments!

Eco-friendly, Environmental Hazards, Science

Cigarette Butts Could Soon Be Turned Into Something Useful

A research team in Australia has come up with a way to turn cigarette butts into pavement.
Soon, these nasty things may be IN your asphalt, not ON it. Photo via Pixabay

How do you take the remains of a nasty habit and turn it into something that benefits everyone? Researchers at RMIT University in Melbourne, Australia, may have a solution.

Every year, trillions of cigarette butts are produced worldwide, and most of those are discarded into the environment. Loaded with toxins, they take a very long time to break down, and when they do, all their poisonous chemicals are released into waterways.

But the team at RMIT University, led by Dr. Abbas Mohajerani, has shown that cigarette butts can be mixed with asphalt and lead to a product that not only tolerates wear and tear of daily traffic but also reduces thermal conductivity.

What this means is that the disgusting remains that some inconsiderate smokers leave behind can solve a big waste problem and could help to reduce the urban heat island effect common in large cities.

“I have been trying for many years to find sustainable and practical methods for solving the problem of cigarette butt pollution,” said Mohajerani, a senior lecturer in RMIT’s school of engineering.

“In this research, we encapsulated the cigarette butts with bitumen and paraffin wax to lock in the chemicals and prevent any leaching from the asphalt concrete. The encapsulated cigarette butts were mixed with hot asphalt mix for making samples,” he added.

About 6 trillion cigarettes are produced each year, resulting in more than 1.2 million tons of cigarette butts. As the world’s population—and the number of smokers—continues to grow, these numbers are expected to increase by more than 50 percent by the year 2025.

“Encapsulated cigarette butts developed in this research will be a new construction material which can be used in different applications and lightweight composite products,” Mohajerani said. “The only ways to control [the chemicals in the cigarette waste] are either by effective encapsulation for the production of new lightweight aggregates or by the incorporation in fired clay bricks.”

How’s that for an unlikely solution to a big problem? I think this idea is pretty darn brilliant, and I’ll be curious to see how the research plays out in real-world applications.

Nature, Science

The World’s Oceans Now Have A Health Record

The oceans now have a health record, thanks to a team of scientists at UC Santa Barbara

Thanks to a team of researchers at UC Santa Barbara, the world’s oceans now have a health record.

And that health record is revealing clues about what might be behind ocean improvements or declines.

Analyzing data from 220 countries, the team gathered five years’ worth of ocean “vital signs” in a variety of areas ranging from water quality to food provision to tourism potential in order to create an Ocean Health Index. Their conclusion: While ocean health appears to be stable, the oceans around many of the countries analyzed are changing for the worse.

“With five years of assessments about where oceans are healthy and not as healthy, we finally have enough information to get a clear signal of what might be causing changes,” said study lead author Ben Halpern, executive director of the National Center for Ecological Analysis and Synthesis at UC Santa Barbara.

Countries like Indonesia, Mexico, and Samoa, that are seeing improvements in their oceans are taking action to make things better, including improving management of wild-caught fisheries and creating marine protected areas.

On the other hand, the countries that saw a decline in ocean health where in consistent political turmoil. Many Arctic and sub-Arctic countries are seeing declines as well, due to the fact that coastlines are losing sea ice, which is a natural protection from storm damage and erosion.

“The Ocean Health Index created the first opportunity any of us has had to measure the health of our oceans in a comprehensive way and track changes with a single measure,” Halpern said.

According to the researchers, the index has scored the oceans’ overall health staying steady at a 71 out of 100. This shows that while the oceans aren’t dying, they aren’t thriving, either. The team will continue to collect data on ocean health every year.

“We believe the Ocean Health Index gives reason for hope by providing a detailed diagnosis of the state of ocean health and a framework that allows countries to identify and prioritize the most necessary resilience actions to improve ocean health,” said study co-author Johanna Polsenberg, senior director of governance and policy for Conservation International’s Center for Oceans. “This is where our work is most valuable. It helps to identify and highlight the necessary steps to ensure a healthy ocean into the future.”

I don’t know about you, but after seeing all the news about dying reefs, pollution, and overfishing, I’m surprised the oceans are as healthy as they are. Hopefully this new information will help governments and scientists to improve their health.