nuclear chemistry

Irradiation to enhance food safety

Does anyone remember the E. Coli breakout back in 2006? I do. There has never been a quicker way to convince a 19-year-old to eat vegetables until you take lettuce out of their sandwiches for a couple of months.

According to the LA Times report[1], these greens are washed in potent chlorine bath, often up to three times, before they are bagged and shipped to the retailer. This standard procedure has a reported 90% effectiveness in killing the microorganisms that may cause harmful effects to the human body.

I don’t know about you, but I would rather not take that 10% chance to get sick. In the single breakout of E. Coli due to cross contamination with the cattle back in 2006, 200 people became ill and three lost their lives. That’s the 10% chance that nobody should have to take.

This past month at the ACS National Meeting in New Orleans, researchers from the USDA presented their findings and results of radiation treatment of fresh produces. Irradiation of high energy beams of photons or electrons, said the scientist, can disrupt the DNA of these pathogens. While the chlorine rinse offers a 90% effectiveness in killing bacterias on the surface of the leaves, it is not able to penetrate beneath the surface. Irradiation method has a reported >99.9% effectiveness in wiping out pathogens such as E. coli, salmonella and listeria, and the high energy beams allows penetrating power that works inside and outside the leaves.

Some members of the scientific community are calling irradiation one of the “few intervention steps that indeed can penetrate the leaf surface and kill microorganisms.”

Irradiation for enhancement of food safety is permitted for some hamburger meat, poultry and spices, but not for fruits and vegetables. However, there has not been any health problems associated with eating irradiated food. So why is FDA steering away from adopting an improved method that could potentially save lives?

Consumer experts and food safety researchers offer some of their speculations:

1. Irradiation may damage the apparence of the product, which may not be as appealing to the customers
2. Nobody would buy lettuce from a bag with a radiation sticker
3. The treatment could shorten shelf lives of the products
4. Technically, irradiated produces cannot be certified organic

Though reasonable, it is hard to believe that the above mentioned points would stop either FDA or independent research institutes from further investigating in a method that could possibly be so much more potent in eradicating pathogens than the existing practice. Perhaps these novel ideas would not suffer as much if we could deliver more transparent and correct ideas regarding the applications of radiation.

Using innovative ideas to improve the quality of our everyday lives, isn’t that what science is all about?


[1] USDA scientists say irradiation could be key to food safety

P.S. True to scientific spirit and for the benefit of the minorities out there, I will summarize and translate my discussion in lolcat. I can has radeashuns: on ur vegitablez, keelin ur baktiriaz.

Edit: Originally mentioned by Bethany Halford and Lisa Jarvis in Chemistry Newsbytes.

By April 22, 2008 9 comments nuclear chemistry, science news

Time Machine Possible in New Particle Accelerator

In recent years, time traveling has been not only a scenario in science fictions and Hollywood blockbusters, but also a scientific possibility due to the rapid developments of quantum theory. Tidbits on the possibility of achieving time traveling has sprouted up in news in the past couple of weeks.


The soon to be available Large Hadron Collider (LHC, pictured above) of CERN utilizes several superconducting magnets (kept at just 1.9 K) to guide charged particles to a desired projectile. Scheduled to be in operation by May of this year, it is the largest and highest energy particle accelerator in the world.[1] Using the LHC, a special run is scheduled for April 2008 in attempt to recreate the Big Bang.

By colliding charged particles at high velocity, researchers hope to reproduce the first billionth second after the Big Bang. By successfully doing so, this exercise would further validate the theory–some claim as the origin of life–since the Nobel win of Professor George Smoot in 2007.

However, the public hype of the launch of LHC isn’t all for the recreation of the mysterious Big Bang. Much of its attention is the possibility of creating a time machine as a side product of this exercise. As mathematicians Irina Aref’eva and Igor Volovich of Moscow’s Steklov Mathematical Institute pointed out, Einstein’s theory of general relativity suggests that particle collisions at such high energy level would distort the space-time fabric surrounding it. This distortion can create a wormhole, or “time tunnel,” allowing time traveling.[2] A related interview with Irina Aref’eva is available on YouTube.

Such claim sounds little more than a scene out of some scifi movie; and many in the scientific community agrees. Most remains skeptical of the production and application of the man-made wormhole. Surely, arguments like the lack of “time travelers” from the future still echo every time machine idea is brought up. Since what will happen inside the particle accelerator is still largely unknown, its secondary consequences also remain unpredictable.


[1] Large Hadron Collider, Wikipedia

[2] The world’s first time machine? Tunnel to the past could open door to future within three months, say Russians

By February 19, 2008 9 comments nuclear chemistry, science news

New Isotope Discovery: Borhium-260

The discovery of a new isotope of Bohrium, by Nelson et al. (I’m a coauthor as well), was published yesterday in PRL. In total, 8 events of 260Bh were reported. Unfortunately, the new isotope is not long-lived enough to be of practical chemical interest. A summary of the decay properties is summarized in the Nuclear Trading Card format shown below.

Bohrium 260

The yellow color signifies the observation that it decays by alpha emission 100% of the time. The nuclide decays into 256Db, which is long-lived enough for chemistry, and the results taken with this paper and others updates the known decay properties of Dubnium-256. The updated trading card is below.


In this case the red signifies an ~30% electron capture branch. I hope you enjoy the announcement of a new member to the Bohrium family, and have fun with your new nuclear trading card.

Note 1: Link to article: Lightest Isotope of Bh Produced via the 209Bi(52Cr, n)260Bh Reaction

Note 2: Comments, if any, should be posted at the ACS-DNCT Blog


By January 15, 2008 0 comments nuclear chemistry

Plutonium Polymer Mystery Solved

Earlier this week a paper by L. Soderholm et al. in Angewandte Chemie may have solved the great plutonium polymer mystery. Plutonium polymer is the ubiquitous noun often spoken by plutonium chemists in regards to the un-extractable ill-defined hydrous oxides of plutonium that will form in any solution of aqueous plutonium lying about the bench top. Often plutonium polymerization can be inhibited by storing aqueous plutonium solutions at high acid concentrations. It was thought to form from a series of olation reactions:Plutonium Olation Reaction: Pu—OH + Pu—OH2 —> Pu—OH—Pu + H2O

This old hypothesis is put to rest with the isolation of Li14(H2O)n[Pu38O56Cl54(H2O)8]. This occurred after repeated anion-exchange with an acidified alkaline peroxide solution of plutonium, that then crystallized in the presence of aqueous LiCl. This type of workup is common for samples containing plutonium polymer. The crystal is reported to have the same intracluster packing and structural topology as bulk PuO2. The crystal structure of the [Pu38O54(H2O)8]40+ is shown below-left and a picture of the [Pu38O56Cl54(H2O)8]14-is shown below right.

Plutonium cation nanoclusterPlutonium cation nanocluster

Reprinted pending permission from John Wiley & Sons, Inc.: Angewandte Chemie International Edition (Dec 2007).

The Plutonium is in green, oxygen from the oxide in red, and oxygen from water in blue. With this and other evidence of well defined Pu—O clusters and the lack of hard evidence for oxyhydroxides they expect plutonium to condensate through an oxolation reaction.

Plutonium Oxolation Reaction: 2Pu—OH —> Pu—O—Pu + H2O

The one caveat with this work is that it was performed with the more stable plutonuium-242 (t1/2=3.7 x 105 y) and not the typical reactor plutonium-239 (t1/2=2.4 x 104 y). Perhaps in the presence of the >10x more radioactive Pu-239 the nanoclusters would become either too structurally damaged to resolve nice crystalline structures, or more chemically reactive towards hydrous oxide formation or oxyhydroxide formation. Regardless, this work may still lead to better methods of extracting plutonium out of the nuclear fuel cycle and represents a nice resolution to the nebulous plutonium polymer conundrum.

Link to Paper:


By December 13, 2007 0 comments nuclear chemistry