Tag Archives: uranium

Modhere Sacred Well.

India’s aquifers show “widespread” uranium contamination

When in India, you might want to be careful where you drink water — a new study found widespread uranium contamination in aquifer-drawn groundwater in 16 Indian states. The researchers point to over-drainage of these water-bearing bodies as a probable cause.

Modhere Sacred Well.

Modhere Sacred Well, Shenzhen, China.
Image credits Bernard Spragg / Flickr.

A new study led by researchers from Duke University reports that aquifer groundwater in India shows high levels of uranium contamination. The main source, they believe, is the chemical make-up of the rock layers which hold the water. Human activity such as pollution and over-drainage may be exacerbating the problem, however.

Dangerously uranic

“Nearly a third of all water wells we tested in one state, Rajasthan, contained uranium levels that exceed the World Health Organization and U.S. Environmental Protection Agency’s safe drinking water standards,” said Avner Vengosh, a professor of geochemistry and water quality at Duke’s Nicholas School of the Environment and paper co-author.

Data recorded during previous water quality studies revealed aquifers with similarly-high levels of uranium in 26 districts in northwestern India and in 9 districts in southern and southwestern India, the paper adds. The study is the first to highlight a widespread presence of uranium in India’s groundwater. Uranium exposure has previously been linked to health complications such as kidney disease.

Based on the findings, the team believes there is a “need to revise current water-quality monitoring programs in India” and to face the potential public health risks in areas with high levels of uranium contamination.

“Developing effective remediation technologies and preventive management practices should also be a priority,” Vengosh adds.

According to provisional safety standards set by the World Health Organization (WHO), which are consistent with standards set by the U.S. Environmental Protection Agency (EPA), around 30 micrograms of uranium per liter of water should cause no adverse effects for humans. However, uranium isn’t currently on India’s water quality watchlist, the Bureau of Indian Standards’ Drinking Water Specifications.

For the study, the team sampled and analyzed the chemistry of 324 wells in the states of Rajasthan and Gujarat. In one subset of samples, they measured the ratios of uranium isotopes. The dataset was fleshed-out with measurements from 68 previous groundwater chemistry studies performed in Rajasthan, Gujarat and 14 other Indian states.

The results suggest that there are several factors contributing to this contamination. The source is natural, the team writes — uranium contained in the aquifer’s rocks leaching out into the water. The quantity of uranium contained in the rocks of each is the first factor. The others include water-rock interactions, oxidation conditions that enhance uranium’s solubility in water, as well as the presence of chemicals in the groundwater that can interact with this extracted uranium (such as bicarbonate) which further enhances the metal’s solubility. These last three factors are specific to each water-bearing body — but, in many areas of India, they compound and lead to high concentrations of uranium in the water.

Human activity also plays a central part, the team notes. The most important culprit is over-exploitation of aquifer water for crop irrigation.

Most Indian aquifers are composed of clay, silt, and gravel resulted from the weathering of rocks in the Himalayas, or from uranium-rich granites eroded by streams. If these aquifers get drained faster than they can replenish (so water levels decline), it creates an environment ripe for oxidation — in turn, this makes what groundwater is still in the aquifer leach uranium much faster.

“One of the takeaways of this study is that human activities can make a bad situation worse, but we could also make it better,” Vengosh said.

“Including a uranium standard in the Bureau of Indian Standards’ Drinking Water Specification based on uranium’s kidney-harming effects, establishing monitoring systems to identify at-risk areas, and exploring new ways to prevent or treat uranium contamination will help ensure access to safe drinking water for tens of millions in India.”

This contamination is just the latest in a long string of problems India is having with its groundwater supply lately. Over-consumption is quickly drying its aquifers, threatening to leave its population wanting for water. But these findings show that the country’s immense drain on underground water resources is already starting to have adverse effects.

Furthermore, India’s groundwater “also suffers from multiple water quality issues such as arsenic and fluoride contamination that pose human health risks,” according to the paper.

The paper “Large-Scale Uranium Contamination of Groundwater Resources in India” has been published in the journal Environmental Science & Technology.

A radioactive couple: the glowing legacy of the Curies

A motif present in virtually all Balkan countries’ folklore is that of the creator sacrificing part of himself for his work. In Romanian folklore, this theme surfaces in the story “Meşterul Manole“, who immured his wife in the walls of the monastery he was tasked with building. I couldn’t help but remember that story as I was reading about the Curies, who laid the groundwork on which our understanding of radioactivity is based.

Marie and Pierre Curie.
Image via Wikimedia, author unknown.

Marie Curie, born Maria Sklodowska in Warsaw on November 7, 1867, was the daughter of a secondary-school teacher. She received a general education in local schools with some scientific training from her father. In 1891, she went to Paris to continue her studies at the Sorbonne University where she obtained Licentiateship in Physics and Mathematical Sciences. There, she met Professor of Physics Pierre Curie and in 1895 they got married.

But that’s just context — this story starts in 1895, when German physicist Wilhelm Roentgen discovered X-Rays but couldn’t uncover the mechanisms by which they formed. One year later, in 1896, French Nobel Laureate Henri Becquerel discovered that uranium salts spontaneously emit radiation very similar to X-Rays and proved that they originate from the uranium atoms.

Uranite (or pitchblende) crystals from Topsham, Maine.
Image via wikipedia, credits to Rob Lavinsky.

Intrigued by these findings, Marie started her own research on pitchblende, today sought-after as an uranium ore. Using a version of the electrometer that her husband had developed fifteen years earlier, she discovered that the “uranium rays” caused the air around the samples to simply conduct electricity. Using this method, she observed that the pitchblende with higher uranium content would give off stronger radiation. She also recorded this behavior in minerals containing thorium.

Then one day, as she was performing radioactivity measurements on a samples of pitchblende, she recorded a much higher radioactivity than its uranium content would allow for — and there’s no thorium in pitchblende. The only explanation was the presence of another, unknown radioactive element. This is when Pierre, excited by the idea of discovering a new element, put his own research aside and started working with Marie.

The two would go on to discover Polonium, named for Marie’s home country, and Radium, from the Latin word for ray, in 1898. They also coined the term “radioactivity” to describe the effects seen by Becquerel. Either together or separately, they published more than 32 papers, including the first paper to describe how tumors can be destroyed by exposure to radium. Their work attacked the previously held beliefs that atoms are indivisible.

Their work wasn’t even sponsored by the University, the couple drawing on private, corporate and government funds. Unaware of the dangers they were exposing themselves to, they worked either in their home laboratory or out in a converted, leaky shed next to the School of Physics and Chemistry. They wore no protective gear, just woefully inadequate lab coats.

Their achievements and vision helped shape the world as we know it. But as Uncle Ben used to say, “with great scientific results comes great genetic damage by processes you don’t yet fully understand,” or something close to that.

The Curies’ work literally bathed them in radiation, day in and day out for decades. They handled samples without any care or protective gear. They took the pieces of radium they were able to refine — and today we know this is the most radioactive element in the periodic table — in their bare hands to examine. Even when she wasn’t in the lab, Marie carried her passion with her: she would have test tubes of radioisotopes in her pocket or stashed in her desk drawer.

Radium clock-hands from 1940-1950’s watches.
Image credits Mauswiesel.

The Curies knew about radioactivity but had no idea of the damage it was wreaking on them. Their research attempted to find out which substances were radioactive and why, so many dangerous elements–thorium, uranium, plutonium–were just sitting there in their home laboratory.

“One of our joys was to go into our workroom at night; we then perceived on all sides the feebly luminous silhouettes of the bottles or capsules containing our products. It was a really lovely sight and one always new to us,” she wrote in her autobiography.

“The glowing tubes looked like faint, fairy lights.”

Pierre died 19 April 1906, aged 46, run over by horse-drawn carriage on a rainy day in Paris. Marie continued their research and had several breakthroughs. She died at age 66 in 1934 from aplastic anemia, believed to be an effect of her prolonged exposure to radioactive materials.

Now, researching any famous historical figure is a daunting task, and there are mountains of obstacles to overcome if you want to get your hands on any of their papers or objects. But in the Curies’ case, it’s actually dangerous to do so. Because of how they worked, their papers, clothes, pretty much every worldly possession is still dangerously radioactive — and will be for at least 1,500 years to come. If you want to look at her manuscripts at France’s Bibliotheque Nationale, you first have to sign a liability waiver. Only then can you access the papers, which are stored in a lead-lined box.

Marie Curie’s manuscript. A book to die for. Literally.
Image credits The Wellcome Trust.

Their house remained in use up to 1978 by the Institute of Nuclear Physics of the Paris Faculty of Science and the Curie Foundation. Authorities finally became aware of how insanely dangerous it was when people in their neighborhood, suffering from very high rates of cancer, blamed the Curies’ home. The building and laboratory were decontaminated in 1991.

Marie Curie was an incredibly gifted person, and her achievements speak for themselves. From a humble birth, she was to become the first woman to ever hold the position of Professor at the University of Paris, the first woman to win a Nobel prize, the first and only woman to win it twice, the only person to have ever received the award in different fields of research and the first woman to be entombed for her merits at the Panthéon in Paris. Pierre was a pioneer in the fields of crystallography, magnetism and piezoelectricity, in addition to his work with Marie, for which he jointly received the Nobel Award.

Together, these two brilliant people forever changed how we understand the world we live in. They did so at a huge cost, with incredible levels of radiation exposure, that would in the end claim Marie’s life. But by tackling some of the deadliest forces known to man with their bare hands, they earned life unending in the scientific community.

 

High-resolution spectroscopy could revolutionize seawater uranium capture

New imaging techniques might revolutionize the technologies currently used to capture uranium from seawater, as researchers gain a better understanding of the way the compounds that bind the atoms interact with them.

Using high-energy X-rays, researchers discovered uranium is bound by adsorbent fibers in an unanticipated fashion.
Image via phys

A research team led by Carter Abney, Wigner Fellow at the Department of Energy’s Oak Ridge National Laboratory, used ultra-high-resolution imaging to study the polymer fibers that bind uranium from seawater. Their results, gained through collaboration with the University of Chicago and published in a paper in the journal Energy & Environmental Science, shows that these materials don’t behave the way computational models say they should.

“Despite the low concentration of uranium and the presence of many other metals extracted from seawater, we were able to investigate the local atomic environment around uranium and better understand how it is bound by the polymer fibers,” Abney said.

By looking at the polymeric absorbent materials with X-ray Absorption Fine Structure spectroscopy at the Advanced Photon Source, Argonne National Laboratory, the researchers found that the spectrum response from the polymers were very different from what they were expecting to see based on previous small molecule and computational investigations.

They concluded that for this system the approach of studying small molecule structures and assuming that they accurately represent what happens in a bulk material simply doesn’t work. What is needed is to consider the behavior of the molecules in-bulk, to take into account interactions that only start working in a large-scale setting, says Abney.

“This challenges the long-held assumption regarding the validity of using simple molecular-scale approaches to determine how these complex adsorbents bind metals,” Abney said. “Rather than interacting with just one amidoxime, we determined multiple amidoximes would have to cooperate to bind each uranium molecule and that a second metal that isn’t uranium also participates in forming this binding site.”

(Amidoximes are the chemical group attached to the polymer fibers that bind the uranium atoms.)

Armed with this knowledge, Abney and colleagues hope to develop absorbents that can efficiently harvest the vast quantities of uranium dissolved in seawater.

“Nuclear power production is anticipated to increase with a growing global population, but estimates predict only 100 years of uranium reserves in terrestrial ores,” Abney said. “There is approximately 1,000 times that amount dissolved in the ocean, which would meet global demands for the foreseeable future.”

Uranium Crystals May Lead to Safer Nuclear Fuels

Idaho State University researchers have created uranium crystals by crushing nuclear fuel pellets and heating them in a furnace. This was made with the purpose of studying a single uranium crystal, understanding how heat would flow through it, and ultimately develop safer fuels for nuclear reactors.

Uranium crystal. Credit: INL

Uranium crystal. Credit: INL

Eric Burgett, a professor at the University of Idaho, has developed cerium oxide crystals as a practice run, and then moved on to uranium.

“A single crystal allows researchers to test and study a material in its simplest form,” said Burgett, who also is a Center for Advanced Energy Studies affiliate.

The main problem with uranium oxide fuel pellets is that they are composed of multiple crystallites randomly mixed together and whose microstructural makeup can vary from batch to batch – making modelling and predicting them very difficult.

“About 95 percent of the crystals that make up the uranium oxide are randomly oriented. There is no order,” Burgett said. “How can you accurately model and simulate a fuel pellet crystal with randomness? With the crystals we are growing, you can. We will be able to examine a single uranium or uranium oxide crystal and how heat moves through it. That gives us a baseline to understand what happens to the material as it gets more complex and the crystal structure changes.”

INL and other scientists will subject the crystals to a variety of tests to better understand how the material behaves – a crucial part of developing a better type of uranium fuel.

“The more you understand a material, the better you can design a material,” Kennedy said. “These single crystals will allow us to study and understand uranium and uranium oxide in its simplest form.”

Source

Grand Canyon Colorado River

Uranium mining near the Grand Canyon set for debate

Grand Canyon Colorado River

The Grand Canyon area is a veritable national symbol for the US, and nature alike. Its frightening, yet brilliant view of the surroundings canyons and boulders makes for a unique sight in the world, which is why millions of visitors flock towards it every year. The site, apparently, also holds one of the richest uranium ore deposit in the continent, which mining companies intend on exploiting. If operations would to commence, however, a severe risk of pollution in the area, especially fresh water contamination of the Colorado river, might be at stake.

The whole situation seems extremely tense, especially pollitically-wise. A million acres of land near the Arizona strip were declared mining prohibited this past June, however a new bill called House Resolution 3155 led by republicans is intending to lift the prohibition and allow mining operations on a 40 miles long, 40 acres wide area in Arizona, near the Grand Canyon.

Democrats soon picked on the bill, as soon as it entered Congress, citing the mining will pose extreme hazards for water sources downstream. On the Huffington Post blog last week, former Florida Congressman Alan Grayson claimed that at the uranium mine near the Colorado River in Utah, “16 million tons of radioactive debris have been produced, and that taxpayers are spending $720 million to move that radioactive debris away from the river.”

The republicans have a counter-point, though. The Mojave county, the area on which supposed uranium mining would operate currently has an unemployment rate of 11%, toppled by whooping 52% among the Native Americans living the Navajo reservation.  A study done by the American Clean Energy Resource Trust, called the Economic Impact of Uranium Mining on Coconino and Mohave Counties, found that mining banning would cost the county alone $40 million.

“…1,000 new jobs will be eliminated, $2 billion in federal and state corporate income taxes will never be paid, and over $175 million in taxes and fees will be lost to local governments,” said Mohave County Supervisor Buster Johnson in a testimony before Congress this fall.

U.S. currently imports 90 percent of the uranium needed to operate our 104 nuclear sites, but this could change if the nation had enough raw material of its own, like the 375 million pounds of uranium estimated in the Grand Canyon area. Republican Trent Franks officials, who actually led the proposition for H.R. 3155, cite that the Bureau of Land Management, the U.S. Geological Survey, and Arizona State University studies have shown no threat to the surrounding water supply by mining this uranium.

“This shameful effort by the Obama administration is a step precisely in the wrong direction for the American economy, making the U.S. even more dependent on foreign powers and potentially creating a serious national security threat going forward,” said Congressman Franks.

Both sides have extremely valid points, and maybe the only way to tell what’s the best decision to take is to understand where the greatest wrong could come from. Around 10 million visitors come to the Grand Canyon every year, and approximately 27 million more depend on the water supply of the Colorado River. If it gets contaminated, the billions of dollars saved by the government will be worthless.

Meanwhile the H.R. 3155 seems to be at a stalemate, and might remain so for long time.

source

Bacteria nanowires clean up Uranium contamination

Ever since uranium has been mined and atomic bombs have been tested, some areas have had to deal with the contamination of sediments and groundwaters by toxic soluble uranium. Now, this problem could be solved with filaments growing from a specific bacteria.

Some clean-up methods already use the bacteria to solidify Uranium in sediments, but the whole phenomena is not yet well understood, and as a result, cleaning up this radioactive element is extremely problematic. However, a team of researchers from Michigan State University has identified a group of bacteria known as Geobacter, which produces tiny protein filaments, or nano-wires, that remove the dissolved uranium from waters and precipitate it outside the cell. Their research explained how the whole phenomena works, and how it can be used to our advantage.

Practically, the filaments transform the soluble form of uranium into a less-soluble form which is much more easy to remove from sediments. The reaction is interestingly enough a by-product of the bacteria’s own metabolism, which generates energy by altering the chemistry other metals.

The team has found a way to purify the nano-wires in the natural population of Geobacter, and to genetically increase their concentration. They claim that “envisions these nano-wires being incorporated into devices, for use in places like Chernobyl and Fukushima where the radiation is too high for the bacteria to survive.”.

Such a filament measures only four nanometers across, but many of them create a network several times bigger than the cell itself, and the amount of solid uranium deposited is proportional to the number of filaments.

Via BBC

The new safe face of nuclear energy

There seems to be a global trend against atomic energy, even though coal is much, much more dangerous in the long run. Germany, for example, has announced giving up all of its nuclear energy until 2022, in what has been called by many a rash and uncalculated move. However, on the other hand, other people are going for a different, more sane approach.

Kirk Sorensen believes safe nuclear power can contribute significantly to the world’s energy future – provided that reactors run on liquid thorium fuel instead of solid uranium, like it is done today. Showing the courage and determination behind his claims, he launched his own company, called Flibe Energy, which aims to start the first thorium reactors in 5 to 8 years.

Sorensen claims he also wants to revefine the general opinion on nuclear energy, showing how relatively clean and cost effective it is, contrary to the popular belief, which fears nuclear waste and nuclear power accidents. This mission is extremely tougher after the incidents which took place at the Fukushima plant in Japan.

“In the 40s and 50s they had an expansive definition of what nuclear power was – it wasn’t just solid fuel uranium reactors,” said Sorensen, who is Flibe’s president. “But that’s what it has come to mean now.”

What is ironic is that Thorium lost the battle against Uranium because it doesn’t have any lethal waste produts, like Uranium has Plutonium for example; thus, the waste couldn’t be used for military purposes, which was a clear goal during the Cold War years. Today, other countries, especially China and India are pursuing Thorium reactors.

Although in some cases Thorium does produce Plutonium as a waste product itself, the waste is less hazardous than other mixes of plutonium waste and there is much less of it. Also, Thorium based fuels are much more effective than Uranium, so the same amount of energy could be produced with less fuel.

“The hotter you can get, the more efficiently you can turn heat into electricity,” said Sorensen. “Typical reactors today, they only get about one third conversion efficiency. We can get about half.” He also claims that in his design, thorium “isobreeds”, meaning it creates as much fissile fuel as it burns up.

Of course, perhaps the most powerful enemy he will have to face is the nuclear supply chain which is heavily vested in solid uranium 235. But this seems like a very healthy move, and one we should definitely keep an eye out in the following years.