isotopes

Shades of L’Aquila: Italian Geochemists avoid Huge Miscarriage of Justice

Matt Herod December 3, 2014

On rare occasions I hear about a story that must be told. This story is one of those and I feel that it deserves attention from the broader geoscience community.

We have all heard of the L’Aquila verdict against the Italian seismologists concerning the devastating earthquake in 2009. If you haven’t, read these articles by Chris Rowan. At the time the guilty verdict was handed down the entire geoscience community felt stunned that such a thing could have happened. The prevailing attitude was that it should not be possible to accuse and convict scientists for practicing responsible science. However, the old adage goes: those who don’t learn from history are doomed to repeat it. This brings me to the topic of this post, which was a very near miss by the Italian justice system against four geochemists from the University of Siena.

I originally heard of the story at Goldschmidt 2013 in Florence during a presentation by Dr. Luigi Marini and I wrote a short note about it in my daily summary of the conference on this blog. After the conference I asked Dr. Marini for more information as I felt the details of this case needed to be heard. I recently heard back from Dr. Marini that the case has now been resolved in favour of the geochemists and I am now free to write about their story on this blog.

The story begins, in December 2002, with several geochemists from the University of Siena being asked by the Italian Ministry of Defense to perform a geochemical-environmental study in the Sardinian Poligono Interforze Salto di Quirra (PISQ), comprising the two firing ranges of Perdasdefogu and Capo San Lorenzo.

Numerous different military activities were carried out at the PISQ since July 1st, 1956, including: (i) launch of rockets (ii) release of bombs from airplanes and helicopters (iii) use of artillery, from land and ships (iv) tests of pressurized pipes.

According to media and some local associations, Depleted-Uranium (DU) ammunitions were used in the PISQ and caused the so-called “Quirra Syndrome”. The “Quirra Syndrome” refers to an apparently greater-than-normal incidence of illnesses in the local population and military personnel that served at the Quirra base. It occurs mainly as cancers and natal genetic malformations. However, the “Quirra Syndrome” has not been confirmed by the Italian national health authority, the Istituto Superiore di Sanità (ISS).

So one of the goals of the Siena geochemists was to determine if DU had been used in tests.

Google screen capture of Sardinia. Quirra, which is the subject of the study, is the red pointed location.

On the face of it the task seems simple enough: analyze soil, plants and water for U and its isotopic ratio and other potential contaminants from the munitions range (of which are there many). However, the complicating factor in all of this is that fact that adjacent to the firing range is an abandoned mine site called Baccu Locci. The Baccu Locci mine contains significant quantities of arsenopyrite and galena, which are arsenic and lead bearing minerals. Both arsenic and lead are known to have detrimental effects on the environment and humans. So the real question then becomes which is it? Mine waste or DU or other military contaminants? Furthermore, historical records from PISQ say no DU was used in the region, however, lots of other munitions with their own suite of toxic components may have been. Therefore, isolating a single cause of the possible impacts on the environment and humans becomes very complex indeed.

Taking a quick step back let’s review some of the basic science in question here.

What is DU?

DU stands for depleted uranium and it was the central contaminant discussed in the case. Uranium comes in many isotopes but the two most common are 238U and 235U. Most uranium found in nature is ~99.2% 238U and ~0.7% 235U. However, most nuclear reactors use fuel that is enriched in the isotope 235U to around 20% as it is more easily fissionable than natural uranium. A by-product of the enrichment process is uranium that is missing its 235U and has a larger proportion of 238U than is normally found in nature. This uranium is said to be depleted as it has had the 235U removed. This DU can then be used for other applications outside of the nuclear industry as it has the rare property of being one of the most dense metals known. This property makes it used in a wide variety of industries but particularly in military applications as a tip for missiles, armour penetrating bullets and other types of scary munitions. DU munitions have been used in Desert Storm, Bosnia, Kosovo and recently in Iraq and Afghanistan and at numerous munitions test sites around the world.

Gunner's mates inspect linked belts of Mark 149 Mod 2 20mm ammunition before loading it into the magazine of a Mark 16 Phalanx close-in weapons system aboard the battleship USS MISSOURI

US Navy personnel inspect linked belts of DU tipped ammunition (Wikimedia Commons)

The problem is that when DU munitions are used the uranium is blown into millions of tiny particulates that can spread on the wind and introduce widespread contamination to the environment. DU contamination is a serious issue. The radiological risks of DU are low in comparison to many other radionuclides due the long half life of 238U and the low energy alpha particles that it emits although they cannot be ignored altogether if the concentration of DU is high. The far greater risk from DU, however, is the high toxicity of the uranium metal itself as it attacks the kidneys in people similar to metals such as lead and cadmium. DU exposure has been linked to cancer, birth defects and other diseases for people living in contaminated areas and diseases afflicting veterans of the Gulf War as it acts in concert with other contaminants from these former war zones.

Acid Mine Drainage

Acid mine drainage is a phenomenon that many geochemists work with every day. In brief it occurs when sulphide minerals like galena (PbS), pyrite (FeS2) or arsenopyrite (FeAsS) are left exposed to open atmosphere and precipitation. What happens is a chemical oxidation reaction in which the sulphide minerals such as galena (PbS), pyrite (FeS) or arsenopyrite (FeAsS) react with air and water to release sulphuric acid and free metal ions. In the case of galena you get lead or arsenic from arsenopyrite.

Rio_tinto_river_CarolStoker_NASA_Ames_Research_Center

An extreme example of acid mine drainage from a mine in Spain. (Wikimedia Commons)

Indeed, Frau et. al. (2009), found significant evidence of contamination from Baccu Locci Mine wastes in streams leading from the region, which is a tributary of the larger Quirra River that flows through the village into the Tyrrhenian Sea. The paper found elevated concentrations of lead, cadmium, zinc and arsenic near mine wastes, however, concentrations decreased downstream due to dilution and precipitation of insoluble lead-arsenic minerals. These heavy metals could have detrimental effect on the health of local residents.

OK, so back to the case.

The researchers from the University of Siena did what was asked of them and analyzed over 1500 samples for a variety of contaminants, including the 235U/238U ratio (on selected samples), totalling 25,000 results. Their findings were that there was no contamination from DU in the region and that the 235U/238U was on par with the natural 235U/238U ratio. However, they did find elevated levels of arsenic and lead around the former mine site and in catchments draining it.

Distribution map of uranium concentrations in top-soils of the two firing ranges of Perdasdefogu and Capo San Lorenzo and nearby areas (from the Siena University report, 2004).

Histogram (left) and statistical parameters of uranium concentrations in the top-soils of the two firing ranges of Perdasdefogu and Capo San Lorenzo and nearby areas (from the Siena University report, 2004).

Furthermore, one of the supporters of the Quirra syndrome conducted health related modelling using a code called HOTSPOT and found that in order to cause the anomalous number of cancers observed in Quirra between 80-140 tons of DU had to have been used, which is an absolutely huge amount (Zucchetti 2005).

These results met with extreme opposition from the local prosecutor who acted on the advice of a nuclear physicist from the University of Brescia who felt that geochemistry was not the proper way to investigate this problem and that the University of Siena scientists were hiding something. Indeed, the physicist felt that thorium was the true culprit and that geochemists were not qualified to analyze for radioactive contamination. (I obviously take great exception to this notion as a radioisotope geochemist and user of an accelerator mass spectrometer). Anyway, the geochemists were charged with two crimes in connection with their results:

Not stating the danger of anomalous concentrations of thorium present at the firing ranges.
Using knowledge the geochemists had gained from their previous work on DU in Kosovo to select methods that prevented them from detecting depleted uranium at PISQ.

In answer to the first charge the geochemists provided results of Th analyses for soils in the Quirra region. These show that there are no Th anomalies present in the soil. Therefore, the notion that Th is somehow the hidden, skulking culprit in all of this is simply not the case.

In answer to the second charge that the geochemists knowingly sampled in such a way as to conceal the detection of DU one simply has to look at the aims of the two investigations. In Kosovo the Siena scientists were sampling a small area with known DU contamination and a documented history of DU use. This makes it much simpler to find DU and sample for it. On the other hand, in Quirra, the use of DU has not been confirmed and the study area was far larger. This means that instead of a small scale, targeted sampling campaign the appropriate investigation tactic was a broad, large scale sampling effort that attempted to give an overview of contamination in the region. If DU was found a more detailed look could then be performed in that specific site. However, since no DU was found no more sampling was necessary.

Ultimately, the court appointed an independent expert to examine the results of the University of Siena geochemists in the light of these two charges before proceeding to trial. The expert found that the methods used by the University of Siena researchers were completely reasonable and that there was no evidence of a Th or DU anomaly. Thus on July 11, 2014 the case against the geochemists was dismissed and they were completely exonerated as the victims of unjustified persecution.

This entire episode was certainly very hard for the scientists from the University of Siena. In addition, it should also serve as a cautionary tale for the larger scientific community. This story can only breed hesitation and reticence on the part of scientists to participate in such efforts to help the public. Such aggression on the part of the local prosecutor is a warning to other scientists to stay away from the Quirra region and avoid the potential liability that comes with it. On a larger scale, this trial warns scientists outside of Italy that participating in issues involving human health, or ones that are emotionally charged, can be a bad thing. This lesson is not one that helps people. By telling scientists that if we don’t like your results we’ll attack you personally only turns us away and ultimately enhances ignorance and short sighted decision making. It will be a sad day indeed when I or others turn down a project because of the liability risk involved when we could actually be helping the public interest by practicing responsible science. I hope that this is not what Italy or other nations are coming to.

Thanks for reading! I would also like to acknowledge Dr. Luigi Marini for keeping me updated over the past several months as the trial progressed and his permission to blog about such an important issue.

References

Cristaldi M, Foschi C, Szpunar G, Brini C, Marinelli F, Triolo L. Toxic emissions from a military test site in the territory of Sardinia, Italy. Int J Environ Res Public Health. 2013;10(4):1631–46.

Frau F, Ardau C, Fanfani L. Environmental geochemistry and mineralogy of lead at the old mine area of Baccu Locci (south-east Sardinia, Italy). J Geochemical Explor. 2009;100(2-3):105–15.

Marini L. – Goldschmidt Abstracts 2013. Mineral Mag. 2013;77(5):1661–817. Available from: http://goldschmidt.info/2013/abstracts/finalPDFs/1685.pdf

Zucchetti M. Environmental Pollution and Health Effects in the Quirra Area, Sardinia Island (Italy) and the Depleted Uranium Case. J Environ Prot Ecol. 2006; 7(1): 82-92

The Most Epic Unboxing Ever

Matt Herod February 18, 2014

There is a strange phenomenon on the internet called unboxing. Unboxing is when a person receives a new package of something and takes a video or pictures of the process of opening it for the first time and posts it online. Mostly, from what I can see, people “unbox” electronics or hockey cards or things of that nature. However, what I have today could be called the granddaddy of all unboxings; I have a series of photos of the unboxing and, initial stages of set-up of the University of Ottawa’s new, 3 million volt, accelerator mass spectrometer (AMS), which cost 5 million dollars. This takes opening your new laptop or that Sidney Crosby rookie card to a whole new level!!! The AMS will be housed in uOttawa’s new Advanced Research Complex.

The accelerator portion in its shipping container being transferred into our new building. (Photo: Dr. Liam Kieser)

Easy does it. Now pivot!!! (Photo: Dr. Liam Kieser

Since I am showing pictures of this incredible piece of equipment being installed I’ll explain a bit about what it is an how it is used as well. I use the AMS in my own work to analyze iodine-129, chlorine-36 and once or twice carbon-14. In short, tools that can be used for groundwater dating. However, the AMS is capable of analyzing for a huge range of isotopes and this allows its use a wide variety of disciplines from health science to homeland security.

The AMS works on the same principles and a regular mass spectrometer, but it has a few key differences that make it extremely powerful.

Lots of boxes to open. (Photo: Dr. Liam Kieser)

Once the boxes have been unloaded the building begins. It is like building an IKEA desk, but somehow more… (Photo: Dr. Liam Kieser)

The process of AMS analysis begins with the preparation of the samples, which involves large amounts of lab time in extremely clean conditions. Contamination of samples with unwanted isotopes is a real problem in AMS so great care has to be taken to prepare good samples. The sample is then mixed with niobium powder and pressed into a steel cartridge. The cartridge then gets loaded into the ion source where cesium ions get fired at the sample like shooting a gun. The Cs ions physically break bits of the sample off the cartridge and these get negatively ionized and accelerated out of the ion source towards the first magnet.

Xiao-lei carefully taking the glass rings that are in the accelerator. These are to kill any free electrons that could escape from the stripper canal as well as keep the ions on a stable flight path. X-rays charged to 3 million volts are very bad! (Photo: Dr. Liam Kieser)

The glass rings all put together with the stripper canal in the centre. The stripper canal is where electron get stripped off the negative ions turning them into positive ions as well as keeping the ions on a straight and even flight path. (Photo: Dr. Liam Kieser)

This is what the ion source looks like. Up to 200 samples sit in the big wheel waiting their turn. The AMS control room is those windows in the background.

Our fancy new SO-110 ion source. (Photo: Matt Herod)

Once the samples leave the ion source they are accelerated to the first bending magnet which can bend an incredible range of masses. From tritium to plutonium tri-fluoride.

The first magnet looking towards the accelerator. (Photo: Matt Herod)

The next step is firing the ion into the particle accelerator that carries a charge of 3 million volts! Inside the accelerator is a passage called a stripper canal that pulls electrons off the ions turning them from negative into positive ions. The reason for this is that this allows us to get rid of interferences that normal mass spectrometers face. For example, chlorine-36 has an interference with sulphur-36 making it impossible to analyse using normal mass specs. Actually, our AMS has another modification that makes 36Cl analysis possible on a 3MV machine, which is generally considered too small for this isotope. Usually, 36Cl needs a much larger accelerator however, our isobar separator for anions (ISA) allows this. Once the ion leaves the stripper canal it is accelerated at very great speed into the next magnet.

Dunh, dunh, dunh. This is the A in AMS! (Photo: Matt Herod)

This is the biggest magnet I have ever seen!! It is over 3m long and weighs 18 tonnes! This is why the room needs an overhead crane. (Photo: Matt Herod)

Once the ions are redirected and isotopes are further separated by the magnet they are ready to be analyzed in either the Faraday cups for the common isotopes or the gas ionization detector for rare isotopes.

Me, touching the Faraday cups. (Photo: Laurianne Bouchard)

The gas ionization detector. This bad boy literally counts atoms as they come around yet another magnet and through a silicon nitride window. Once they enter the detector which is filled with gas they ionize it which leads to pulses of electricity that are counted. This is the end of the AMS!!! (Photo: Matt Herod)

Once the atoms are counted in the gas ionization detector their trip around the AMS is over! It is quite a journey and full of positives and negatives (haha, a little pun there). Seriously, though this gigantic instrument is used to quantify the smallest of small quantities and can very literally count atoms. The AMS has a massive number of possible uses and I’ll likely be posting about these as this new facility starts to ramp up in the next few months. In addition to the AMS we also have an SEM, microprobe, stable isotope equipment, two noble gas mass spectrometers, ICP-MS, LA-ICP-MS, ICP-AES and a host of other MS’s as well. There will be very few types of isotopes that we cannot analyze for and this facility will be one of the best in the world for this type of geological research. Stay tuned for further developments as we start to move in soon!

Cheers,

Matt

It’s rainin’ isotopes…

Matt Herod March 27, 2013

This post is kind of a continuation of Laura Roberts excellent guest post on the Solar Storms and the Earth’s Magnetic field. However, this is a bit of a different spin on it. I am not writing about what get’s kept out, but rather what slips by the shield and gets in. Of course, I am speaking about cosmic rays and the wonderfully useful isotopes they produce that rain down upon us. Yes, it is literally raining isotopes…all the time! I know that this sounds weird, when I first learned about this phenomenon it came as a complete surprise to me. Not only are isotopes raining down all the time, but there is a lot that we can learn about our planet by analyzing these amazing by-products of cosmic ray collisions.

What are cosmic rays?

Cosmic rays are incredible things. The Earth is constantly being bombarded by them and we are protected from this massive influx of extra-terrestrial radiation by our magnetic field and atmosphere, which deflects about 90% of the low energy cosmic rays. Check out last weeks awesome guest post about Earth’s magnetic field. There are two types of cosmic rays. Primary cosmic rays generally originate outside of our solar system and travel throughout space occasionally bumping into things like planets. In fact, it has only recently been discovered exactly where they come from. In February, 2013 a paper came out in Science called: Evidence Shows That Cosmic Rays Come From Exploding Stars that (surprise) stated primary cosmic rays are produced by exploding stars aka. supernovae in which an ancient star blows up, releasing massive amounts of energy, elements and cosmic rays!

Kepler’s Supernova (Source)

Primary cosmic rays are 99% protons and alpha particles (two protons and two neutrons) and the remaining 1% are the nuclei of heavy atoms or beta particles (electrons). These bits of atoms and radiation fly around in space and bang into everything. Sometimes, actually more often than sometimes, they bang into the Earth. In fact, they bang into the Earth a lot! There are billions of collisions every day. Some of the particles crashing into the Earth have low energies while others have high energies. The frequency that these low energy particles collide is many times greater than high energy ones. There are about 10,000 collisions per square meter per second for giga-eletronvolt particles. For the higher energy rays the rate of collision is less. They might arrive with a frequency of 1 per square metre per second, as is the case with tera-electronvolt particles. The decrease in collision frequency continues as energy increases up until the very highest energy of the exa-electronvolt which collides about 0nce per square kilometre per century.

When cosmic rays pass through the Earth’s magnetic field is when things start to get really interesting, from a geochemical perspective that is. When primary cosmic rays enter the Earth’s atmosphere they start banging into all of the molecules and atoms floating around up there and produce secondary cosmic rays. Basically imagine a bowler throwing a strike. The bowling ball represents the primary cosmic ray and the pins are the molecules in the atmosphere. When the ball collides with the pins they fly off in every direction, which is analogous to the process occurring constantly in our atmosphere. When this takes place in the atmosphere the collision is so energetic the molecules and atoms can actually break apart. This is called spallation and results in a cascade of neutrons, protons and atoms called an air shower.

A simulation of a cosmic ray shower formed when a proton with 1TeV (1e^12 eV) of energy hits the atmosphere about 20km above the ground. The ground shown here is a 8km x 8km map of Chicago’s lakefront. This visualization was made by Dinoj Surendran, Mark SubbaRao, and Randy Landsberg of the COSMUS group at the University of Chicago, with the help of physicists at the Kavli Institute for Cosmological Physics and the Pierre Auger Observatory. (Source)

What is produced?

Air showers produce all sort of radioactive isotopes that are formed no other way. Some are very short lived and decay away quickly, while others are extremely long lived and have half lives of millions of years, allowing them to accumulate in the environment.

A list of the major cosmic ray isotopes and their half lives. The ones in bold have geologic applications.

Other isotopes are produced when cosmic rays reach the ground and collide with minerals. This can cause other isotopes to form within the mineral crystal lattice. For example, the cosmogenic isotope, aluminum-26 is produced when a cosmic rays strikes a quartz crystal and transforms some of the silicon in the quartz structure into aluminum. These are referred to as in-situ cosmogenic isotopes.

The next part of the process concerns what happens to all of these isotopes once they have sprung into existence thousands of metres above our heads. The fate of these isotopes is varied and they all live in the atmosphere for a little while before becoming part of the hydrologic cycle. Eventually they fall down to Earth either stuck onto aerosols or incorporated into rain and begin to interact with water bodies, enter groundwater, stick to soil particles or get absorbed into people, plants or animals. Essentially, they begin cycling through the environment until they decay away. Since these isotopes get cycled through various parts of the environment we can use them as tracking tools to trace the pathways they take and learn about their interactions with other components of environmental cycles.

What is the use?

Cosmic rays isotopes are useful for more than just getting a good tan! In fact, the list of possible questions that can be applied to cosmogenic isotopes just goes on and on. I’ll just briefly cover a few of them since each one of these applications is a whole blog post by itself I’ll just give the highlights here.

Exposure age dating: Exposure age dating is one of the principle uses of cosmogenic isotopes and several different ones have been employed to this end. Exposure age dating is when we use cosmogenic isotopes to date how long something has been exposed to secondary cosmic rays at the Earth’s surface. For example, a rock at the toe of a glacier may have just been exposed to cosmic rays a year ago and its exposure age date will tell us this. Another rock, 20 metres further from the glacier toe may have been exposed 5 years ago and this difference will be recorded. Basically, the clock starts ticking once cosmic rays are able to reach the rock or bone, or whatever material is being dated. Exposure age dating has the power to date materials that range from only a few thousand years to millions of years depending on the half lives and concentrations of the nuclides in question. The way exposure dating works is that when a secondary cosmic ray impacts a rock containing Si (silicon) or O (oxygen) some of the neutrons on the silicon or oxygen are knocked off and the result is the production of aluminum-26 or beryllium-10 right in the mineral lattice. One common mineral that contains both silicon and oxygen is quartz. Quartz is pretty much everywhere and in everything, which opens the door for a wide range of materials that can be exposure age dated. All they have to contain is a bit of quartz. The decay of 26Al and 10Be allows the material to be dated. There are other isotopes that can be used for exposure age dating besides these two and other minerals that contain Si or O can also be used as well. The figure below shows the wide range of applications that exposure age dating can be applied to. For example, if you want to date a volcanic eruption it is easy to exposure age date the lava or ash, both of which have a lot of Si. It is also possible to date landslides, erosion rates, burial ages, the list goes on and on. There are many other isotopes that can be used as well besides 26Al and 10Be.

Figure showing all of the different applications of exposure age dating. Ivy-Ochs, S., & Kober, F. (2008). Surface exposure dating with cosmogenic nuclides. Quaternary Science Journal, 57(1-2), 179–209.

CLOUD Project: The CLOUD project is a CERN experiment that is investigating the possible linkage between cosmic rays and cloud formation. It has been hypothesized that cosmic rays can cause clouds to form by forming aerosols and it has been noticed by satellites that an increase in the cosmic ray bombardment can increase the amount of cloud cover. Cloud cover has a profound influence on the Earth’s energy balance and hence climate. It has been proposed that throughout geologic time changes in the cosmic ray flux have been responsible for climate change. However, proving this is difficult given the length of time in question and the evolving states of the cosmic ray flux and Earth’s magnetic field. However, CLOUD has set out to find the linkage between cosmic rays, clouds and climate if one exists.

Carbon-14: Carbon 14 is unquestionably the most used of any of the cosmogenic isotopes. It has applications in geology, archaeology, paleontology, anthropology, hydrogeology, and many other -ologies as well. 14C is produced primarily when neutrons collide with nitrogen in the atmosphere replacing a proton in the nitrogen nucleus and transforming it into carbon-14, although atmospheric nuclear weapons testing also produced a substantial amount of 14C. The primary use of 14C, or radiocarbon, is radiocarbon dating. Once radiocarbon is produced it enters the global carbon cycle and disperses throughout the environment. Since it is part of the carbon cycle it becomes incorporated into all living things, including people and animals. 14C continues to enter our bodies while we are alive. Once we die, there is no further addition of 14C and therefore, the clock starts ticking on its use as a dating tool. 14C has a 5,730 year half life and is therefore useful as a dating tool for biological materials up to ~45,000 years ago.

Cosmic rays are some of the most mysterious, yet useful phenomena on our planet and have allowed for incredible advances in many sciences. As new, more sensitive technology becomes available look for the use of cosmic rays and the isotopes they produce to accelerate as we find new questions they can be used to answer.

Cheers and thanks for reading,

Matt