radionuclides

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 Mysteries of Maqarin

Matt Herod July 19, 2013

We all know that cement is a man-made substance and therefore cement is always synthetic right? Wrong!

In the unusual case of Maqarin, Jordan the stars aligned to produce natural cement and many of the “synthetic” minerals found therein. The Maqarin site has been the subject of an intense geological investigation by a consortium of over 100 researchers for years in an attempt to try and understand this system and its implications. A fairly good overview is available here. Maqarin is located in north-east Jordan, near the border with Syria, in the river valley of the Yarmouk River. The valley is deeply incised allowing a good view of the stratigraphy. There are also several springs coming out of the sides of the valley wall and it is these and their relationship to the unusual geology that make Maqarin so interesting.

A map of Jordan. The location of Maqarin is starred. (Source)

Geologic History

The geologic history of the Maqarin site is very interesting and in many ways unique. Indeed, it was a unique combination of geology and geological events that led to its formation.

1. During the Cretaceous bituminous marls are formed. Basically, rocks that are full of bitumen and calcium carbonate. This rock has up to 20% organic matter! Bitumen forms when organic matter is heated during lithification and is similar to oil. It will burn. The marl is a white, chalky mineral primarily made of CaCO3. There is also about 10% sulphate, which becomes important later on in the geologic history.

2. Overlying the bituminous marls are chalky limestones that were deposited in the Tertiary.

3. The upper unit is basalt, which was deposited during the Pleistocene.

4. The bituminous marl underwent “pyro-metamorphism”. Basically, the rocks were heated to a point where the carbonate rocks cooked and formed high temperature cement minerals such as portlandite, ettringite and thaumasite. The heating though was not due to burial but actually from spontaneous combustion of the bitumen (Khoury et. al., 1992). The presence of sulphate allowed these minerals to form and better simulated a modern cement environment. When the marl, which is CaCO3, is combusted CaO or lime is formed. Then the infiltrating groundwater allows portlandite to form, which then reacted with the suplhates and silicates present to form the other cement minerals.

5. The rocks in the area are all highly fractured allowing water to easily seep through the site. This has led to weathering of the cements. The water seeping through the sites discharges near by and has a pH of 13!!!! The water that seeps through the “cement zone” of the Maqarin site picks up all sorts of dissolved ions and minerals. Remember that heating carbonate + water gives Ca(OH)2. Therefore, there is a huge supply of hydroxide available to raise the pH.

These 5 steps created the Maqarin analogue site as we see it now. Everything had to be perfect for it’s formation to happen: the rocks had to have the right chemistry, pyro-metamorphism had to occur and, the hydrogeology had to allow water to infiltrate and react with the rocks to produce the hyperalkaline springs. See the references below for a more detailed description of the geology and mineralogy of Maqarin.

An image of the Yarmouk River Valley from the Jordan Times. Notice the bedded cliffs along the river. At Maqarin it is these cliffs that have the springs in them. In the distace you can also make out the sraker, overlying basalt. (Source)

Some Geochemistry

I mentioned the “hyper-alkaline springs” above. These springs are super interesting to geochemists, since there not very many places on Earth where we can find springs of highly elevated pH. Indeed, it is much more common to find acidic springs than alkaline ones. However, the springs of Maqarin have exceptionally high pH’s. Why?

The alkaline springs, which flow out of the hillsides at Maqarin, formed due to the unique combination of the hydrogeology, structural geology and mineralogy of the site. As the water infiltrates through fractures in the rock it intially dissolves NaOH and KOH followed by Ca(OH)2, which is the cement mineral portlandite. All of the OH ions that enter solution contribute to the raising of the pH to around 12.5. This now caustic water is then able to react with other minerals and pick up a lot of metals such as uranium, chromium, vanadium and other exotic elements that would usually be insoluble and hence difficult to transport (Khoury et. al, 1992).

The stable isotopes also tell and interesting story about the origins of the water and its pathways at Maqarin. In arid climates, such as Jordan, the groundwater often reflects evaporation that took place either before or during recharge. The waters of Maqarin plot below the local meteoric water line, which is indeed indicative of evaporation before or during recharge of the groundwater. However, there is more to these waters than just evaporation. In fact, the hydration of the cement minerals, such as portlandite, can cause an 18O enrichment, which can also be seen in the Maqarin groundwaters, although it is difficult to differentiate this effect from that of evaporation, which also produces the same trend (Khoury et. al. 1992).

Plot of 18O vs 2H in the hyperalkaline springs of Maqarin, Jordan. The local meteoric water line (Irbid) and the eastern Mediterranean meteoric water line are both shown. Modified from Khoury et. al., 1992.

Why study Maqarin?

We need to understand how cement will behave over long time scales because in most nuclear waste storage or carbon sequestration designs one of the primary barriers between radionuclides/CO2 and the environment are the engineered barriers, many of which are made of cement. In fact, in a repository setting cement is everywhere. It will be used to contain the waste itself, plug up fractures, reinforce structures, and eventually to seal the whole place up. Sealing the place up water-tight (hopefully radio-nuclide tight also) is great, but what happens to the seals when they are subjected to a million years of groundwater flow? Well, the modelling suggests that…. Wait, did I just say modelling? You mean we rely on computer generated geochemical models to tell us what might happen in a number of scenarios? We don’t know exactly what will happen to all that cement that is plugging up a waste site?

An artists depiction of a deep geologic repository for low and intermediate level radioactive waste. (Source)

Enter Maqarin. Maqarin is such an interesting place because “cement” occurs naturally here and it provides a rare opportunity for researchers to actually see how cement and the minerals composing it behave over long time scales when subjected to weathering processes. Therefore, the site can be considered an analogue for the future behaviour of cement in the environment. Indeed, the hydration process that occurs in Maqarin when the groundwater reacts with NaOH, KOH and Ca(OH)2 is exactly what will happen when “man-made” cement is exposed to groundwater. Understanding the geochemistry and hydrogeology of a site like Maqarin gives real-world insights into the outcome of our modelling and we can take the data collected at places like Maqarin and compare them to our model results to verify its accuracy. Furthermore, using observations and empirical data to make conclusions about the future of waste repositories adds a whole new level of confidence in their design or identifies possible weaknesses.

In summary, since radioactive waste storage facilities, which are designed to have million year lifespans, are made of cement it is crucial that we know what will happen to them over long time periods. However, the problem is that modern cement is just that: modern. Therefore, we don’t really know how it will behave in certain environments or when conditions change, or during an ice age, etc, etc. In order to solve this problem we must turn to the next best thing, which is a natural site, such as Maqarin, that mimics the environmental conditions we are looking for and hopefully it can answer some of these questions. Hence, the beauty of the natural analogue.

Thanks for reading,

Matt

References

Khoury, H.N., Salameh, E., Abdul-Jaber, Q., 1985. Characteristics of an Unusual Highly Alkaline Water from the Maqarin Area, Northern Jordan. Journal of Hydrology 81, 79–91.

Khoury, H.N., Salameh, E., Clark, I.D., Fritz, P., Bajjali, W., Milodowski, a. E., Cave, M.R., Alexander, W.R., 1992. A natural analogue of high pH cement pore waters from the Maqarin area of northern Jordan. I: introduction to the site. Journal of Geochemical Exploration 46, 117–132.

My EGU2013 (Tuesday)

Matt Herod April 11, 2013

Firstly, I am not actually attending EGU 2013 this year. However, that does not mean I can’t participate. In fact, it has been incredibly easy for to me join in, although I have had to wake up very early in the morning to make up for the time difference between Vienna and Ottawa.

I took part in two press conferences on Tuesday. The first called: The consequences of nuclear accidents: Fukushima and Europe and promised to be extremely interesting especially from my point of view as a researcher of environmental radionuclides. In fact, I was tuned in for more than just the EGU blogging part since I am in the midst of a project investigating the effects of Fukushima here in Canada and the transport of radionuclides from the accident. I intend to present the work at Goldschmidt later this year and write a publication on it which will comprise a part of my thesis.

The session was started by Dr. Yuichi Onda from the Centre for Research in Isotopes and Environmental Dynamics at the University of Tsukuba.

Dr. Onda and his group are studying the transfer and fallout of Fukushima radionuclides in every aspect of the environment. This is an incredibly daunting task. The infrastructure required to sample so many different environmental reservoirs is mind-boggling and Dr. Onda showed in several of his slides how tough it could be. The group sampled trees, soil, soil water, soil erosion, water in both cultivated and non cultivated environments, sediment in rivers and lakes as well as transport between these reservoirs and then finally the transport to the ocean from all of these sources. Basically, they set up one bad-a$$ monitoring network!

The conclusions from this network were that the deposition process of the radionuclides began by falling on trees but then over time washes off and between .2 and 3.5% of the fallout washes into streams and rivers where it is then transported to the oceans. In a very basic way it kind of looked like this:

Source: Wikipedia

The next speaker was Dr. Kazuyuki Kita from Ibaraki University. He was explaining one step earlier in the whole transport process than Dr. Onda since Dr. Kita’s focus is on the atmospheric transport and dispersion of radionuclides from Fuksuhima. Basically, once the accident occured tons of radionuclides were released into the atmosphere and blown hither and yon until they are eventually deposited in rain or adsorbed onto aerosols and settle because of gravity’s relentless nature. They can also be re-suspended after the fact. This is particularly common with iodine (I know about this one…) Dr. Kita then went on to show a picture of the fallout of cesium-137 over Japan, which is pictured below. Furthermore, the measured concentrations agreed very well with the predictions made by atmospheric modelling, which is a tricky business at the best of time, but must be even more so when the entire world is breathing down your neck asking where will the radionuclides go? The difference were due to rainout, which is difficult to predict.

Slide from Dr. Kita’s talk showing the actual fallout vs. the modelled fallout.

Dr. Kita then went on to talk about the variation of radionuclides in the atmosphere over time following the accident and the influence of re-suspension on radionuclides sitting on the land surface. He showed this graph which illustrates very clearly how 137Cs and 134Cs concentrations spiked following the accident and then declined over time. However, if you look in October you can see that the levels start to rise again, which Dr. Kita attributes to re-suspension. Furthermore, these peaks were coincident with the transport of air parcels from Fukushima as well making it certain that this was the source of the radionuclides. Another source of radionuclides since the disaster has been the re-emission of iodine and cesium from the ocean surface as well.

A slide from Dr. Kita’s talk showing the temporal trend in cesium fallout from Fukushima.

The final talk of the press conference was by Dr. Petra Seibert from the University of Vienna. Dr. Seibert, a meteorologist, gave a truly fascinating, yet somewhat scary talk about how prepared (or not) Europe is for nuclear accidents and the consequences they have with context from both Fukushima and Chernobyl. Dr. Seibert makes the point that despite ample opportunity to learn from our nuclear mistakes we have not addressed all of the deficiencies that exist.

Concerning Fukushima, Dr. Seibert points out that the dispersion of radionuclides from the nuclear plant is not simple and results in contamination outside of predicted zones. This means that the evacuation pattern of simply evacuating people in concentric circles depending on the distance from the plant is not a very effective way of ensuring that people are not affected since the atmospheric spread of radionuclides is not circular. Therefore, in order to be prepared for potential disasters a predictive model of dispersion is needed. Dr. Seibert has developed such a model and shows some of the incredibly variable, and somewhat artistic, results in the following image. The blank space shows a movie of a very complex dispersion.

A slide from Dr. Seibert’s talk showing the incredibly variable nature of radionuclide dispersion from a point source.

Dr. Seibert’s ultimate point is that despite what we have learned from Fukushima and Chernobyl we are not yet prepared enough to handle another large nuclear disaster. Indeed, she makes the point that one in Europe could result in continental scale contamination and that in order to prepare for this proactive measures like iodine tablets should be widely distributed. Furthermore, data distribution and communication between organizations and nations is not adequate as well, which would only serve to exacerbate the seriousness of a nuclear accident should one occur.

In my opinion to keys to avoiding another Chernobyl or Fukushima lies in open communication and learning everything we can from these two disasters. However, I put it to you, what do we still need to learn? What are our shortcomings when if comes to disaster preparedness. Do you agree with measures like iodine distribution in order to mitigate the risk from another accident or should we just cease nuclear energy production entirely?

I also tuned into the fantastic press conference on the Chelyabinsk meteorite fall, but Jon has covered it excellently so head over to his blog a for a summary of it. If you would like to watch the livestream of the press conference for yourself it can be found here: http://streams.h82.eu/EGU2013/index.php?modid=18&a=show&pid=206