VX and Other Deadly Nerve Agents

It has now been confirmed that Kim Jong-nam, the half-brother of North Korean Leader Kim Jong-un, may have been assassinated using a highly toxic nerve agent known as VX. The attack occurred last week (13th February) in Kuala Lumpur airport, suspected to have been committed by two women who reportedly sprayed the chemical into his face before fleeing the scene.

VX, or S-[2-(Diisopropylamino)ethyl] methylphosphonothioate, is a nerve agent initially developed at the Porton Down Chemical Weapons Research Centre in Wiltshire, UK in 1952. Having originally been the focus of research elsewhere into the development of new organophosphate compounds as pesticides, the British military soon established an interest in the compound and continued its development.

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S-[2-(diisopropylamino)ethyl] methylphosphonothioate) or VX

Typically encountered in liquid form, this clear or sometimes amber-coloured, oily substance is notoriously difficult to detect, lacking in both taste and odour. Its toxicity makes it one of the deadliest chemical warfare agents, requiring as little as 10mg adsorbed through the skin to be fatal. Its deadliness is only further increased by the persistence of the agent, making it difficult to decontaminate people and areas tainted with the chemical.

Mechanism

The mechanism of action of VX is identical to many similar nerve agents. The compound can enter the body by a range of potential routes, including ingestion, inhalation or skin contact. Once inside the body, VX inhibits the function of acetylcholinesterase (AChE), an enzyme responsible for catalysing the breakdown of acetylcholine. Acetylcholine is released over a synapse following an electric nerve impulse, ultimately resulting in a muscle contraction. However when VX binds to the active site of acetylcholinesterase, it renders the enzyme inactive, thus preventing it from breaking down the acetylcholine. As the nervous system is flooded with excess acetylcholine,  repeated muscle contractions occur, eventually resulting in asphyxiation due to constant contraction of the diaphragm muscle.

The effects of VX will typically occur immediately after exposure, beginning with coughing, shortness of breath and a tightness in the chest. A headache and blurred vision soon follows, along with symptoms such as vomiting, diarrhoea and abdominal pains. Given a sufficient dose, seizures will then occur as the drug attacks the nervous system, eventually resulting in a coma and asphyxiation.

If administered promptly, there are antidotes for VX. Atropine, typically administered by injection, is an anti-nerve agent that blocks the acetylcholine receptors, alleviating the symptoms brought on by the nerve agent. However it is worth noting that compounds such as atropine are toxic in their own right and, although they may save the person’s life by alleviating the effects of the nerve agent, they will still have an adverse effect on the patient. In addition to this, pralidoxime (or 2-PAM), can be administered to reactivate the enzyme, thus reversing the effects of VX. 2-PAM is a safer compound to use than atropine, but its effects are much slower.

Other Nerve Agents

VX is just one of many known toxic nerve agents. Nerve agents can typically be classed as either G-series or V-series. G-series agents were first synthesised by German scientists during World War II, and include tabun (GA), sarin (GB), soman (GD), and cyclosarin (GF). The first compound to be discovered, tabun, was accidentally synthesised by Dr Gebhardt Schraeder, who was investigating the development of organophosphate-based pesticides. The German army soon realised the potential use of such compounds, and went on to fund the development of other nerve agents such as sarin. The G-series chemicals are all clear, colourless liquids at room temperature, but are largely utilised as gases due to their high volatility.

The V-series nerve agents, which include VX, VE, VG, VM and VR, were developed a few years later, initially in the UK but some later in Russia. Unlike the G-series compounds, V-agents are very persistent and are not easily washed away or degraded, meaning they can remain on surfaces for long periods of time.

Fortunately the V-series nerve agents have generally not been exploited outside of military research, and the death of Kim Jong-nam may well be the first known use of the toxic agent in an assassination. However the G-series have received a great deal of malicious use and attention over the years, ranging from the Tokyo sarin subway attack in 1995 to its recent use in the Syrian civil war

VX, along with numerous other toxic nerve agents, were banned under the Chemical Weapons Convention of 1993, rendering the manufacture, possession and use of such substances illegal.

 

References

BBC News. VX nerve agent: The chemical that may have killed Kim Jong-nam. [online] Available: http://www.bbc.co.uk/news/world-asia-39073558

University of Bristol Chemistry on the Screen. VX Nerve Gas. [online] Available: http://www.chm.bris.ac.uk/webprojects2006/Macgee/Web%20Project/nerve_gas.htm

 

 

 

 

 

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Interview with Forensic Archaeologist & Researcher Amy Rattenbury

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What is your current job role and what does this involve?

By training I’m a Forensic Archaeologist but currently work as a lecturer at Wrexham Glyndwr University teaching on the BSc (Hons) in Forensic Science. My day to day job is teaching student groups across all three years of the programme in a range of subjects such as Crime Scene Investigation, Anatomy & Pathology and the Forensic Investigation of Mass Fatalities. As well as delivering the theory I set up a lot of the practical work that the students do such as fingerprinting workshops, organ dissections and simulated crime scenes that we mock up in our Crime Scene House. I also supervise a number of student research projects mainly in the area of Taphonomy which we conduct on our ‘Body Farm’

What initially attracted you to this field of work?

I had always been interested in science and particularly forensic science and initially took a degree in Forensic Biology at Staffordshire. I always imagined that I would go on to work in a laboratory or doing fingerprint comparisons until I took a module in ‘Identification of Human Remains’. This really sparked my interest in human osteology and made me pursue a MSc in Forensic Archaeology and Crime Scene Investigation at Bradford University where I found my very niche area in search and recovery of human remains. I started teaching anatomy alongside completing my MSc and found a real love for being in the classroom. It gives me an ideal role in being able to share what I’ve learnt so far whilst still being able to pursue my own research and industry related work. Looking back now I can’t imagine not being a teacher. There’s something about introducing students to concepts they had never considered before that really exciting. And sometimes they come back to you later on in their academic careers and actually end up teaching you something; that’s a really rewarding feeling.

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Can you tell us about the research you are currently involved in at Wrexham Glyndwr University?

We are really lucky here at Glyndwr to have Wales’ first and only Taphonomic Research Facility which is licensed by DEFRA. This ‘Body Farm’ allows us to conduct a number of research projects looking at decomposition which could necessarily be hosted by other universities without a dedicated, rural area in which to conduct their research. This coupled with a high calibre research lab in our Chemistry Department has really allowed both myself and students to expand research ideas. Current student projects which are out on the body farm include:

  • The effect of clandestine burial decomposition on soil chemistry and vegetation
  • How tattoo identification is effect by post mortem changes
  • A comparison of decomposition rates in fresh and stagnant water

I am also hoping to set up my own research once the temperature improves slightly and this will be looking at how oxygen deprivation (i.e. vacuum packing) affects taphonomic changes. This is a research project based on a pilot study I supervised, conducted last year by Shareei Singer at the University Centre Southend, and we hope to expand this further by looking at more samples, over a longer time frame whilst also improving the analysis methods used.

What are some of the biggest challenges in your field of work?

Teaching is a challenging role in the first place, but even more so at University level where there is an increased need to challenge students academically, and this can be particularly difficult field to get in to early in a professional career. I’m only 25 so it’s been very much a case of putting myself out there for any and every opportunity to prove myself and gain any experience I can. You really have to show not just your ability as an academic but also a drive and passion for the subject and the students. It is a highly competitive area, not only in terms of securing jobs in the first place, but then going on to conduct and publish research whilst still maintaining high quality, engaging session, for students every week. For me in particular, I find the sheer volume of books and journals I have to read, to ensure that my delivery keeps up with the speed that the area is progressing, a little daunting. But when it’s a subject that I’m passionate about, and books I would likely read anyway, it does make it easier!

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Aside from research, are you often involved in police casework or consultancy work, and what does this typically involve?

I’m not currently involved in any active police work but I did only move up to North Wales around 6 months ago. It is something that I am very keen to start and hope to build up connections in the area to so this. I do some other consultancy work in different areas of forensic search. I work quite closely with UK-K9 who are a search dog training team. They specialise in training dogs to search for a variety of forensic evidence including human remains, explosives and drugs. We are currently working to improve the use of the human remains detection dogs on water and particularly in salt water setting such as costal searches. They are also involved in a lot of cold case reviews and large scale searches which I can offer an archaeological perspective on. I have also recently taken up a consultancy position with Kenyon International Emergency Services who deal with crisis incidents world-wide. I am currently awaiting deployment but once I am called in the role could be anything from collecting evidence at aeroplane crash sites to helping with disaster victim identification during natural disaster.

Do you have any words of advice for students wishing to pursue a career in your field of work?

For students wanting to go in to the forensic science generally just make sure you have it clear in your head before you start that it isn’t going to be how you see things portrayed in the media, I wouldn’t want you to be disappointed or put off once you start the course. I would say trying to get any sort of work experience is going to be crucial. Experience is essential nowadays but still almost impossible to get in crime related areas so think outside of the box a little bit. There are lots of labs you could do placements in that, although aren’t forensic can help you to learn and demonstrate key skills. I worked in a drinking water testing lab and in a haematology lab for a little while, both of which helped learn more about preventing cross contamination. But there are lots of other areas you can volunteer in such as becoming a PCSO, the Appropriate Adult services or any other charity that deals with victims of crime or offenders.

For students wanting to become educators I would say persevere. Remember what made you so passionate about that subject in the first place and share this with you students. It’s amazing how much more progress you make once you’ve learnt to foster this positive learning and collaborative environment. The planning and the marking will get easier, I promise!

 

Follow Amy on Twitter at @amy_rattenbury

Forensics at Glyndŵr can be followed on Twitter or Facebook.

Interview with President of IsoForensics Inc., Lesley Chesson

southern-utahDifferent forms of elements–called isotopes–are found everywhere in the environment. These isotopes are incorporated into materials in varying ratios and the abundances of different isotopes thus serve as a record of the material’s formation. Analysis of a material for its distinct isotope signature can subsequently be used to reveal its history. Investigators have applied stable isotope analysis to a variety of materials of forensic interest including drugs, explosives, money, food, ivory, and human remains. For example, the isotopes in human hair protein can reveal the age of an individual, what s/he ate, and even how often (and where) s/he travelled.

What is your professional background and how did you come to be involved in IsoForensics?

I have a master’s degree in biology, with a lot of microbiology and chemistry experience. I entered the world of isotope forensics when I was hired to raise Bacillus subtilis (a cousin of the anthrax bacterium) under a variety of conditions – in liquid media, on agar plates, with different nutrients, etc. Because organisms record information about the environment in the isotopes of their tissues, the goal of this project was to develop models that allowed investigators to predict the growth conditions of a dangerous bacterium–such as anthrax–from its isotopic characteristics.

From its start in academia, IsoForensics developed into a private analytical services and research firm that explored novel forensic applications of isotope analysis. I enjoyed the challenges offered by that exploration. Since my first work on the B. subtilis project, I’ve been involved in other projects on human remains, foods and beverages, illicit drugs, and explosives.

Tell us about the work IsoForensics is involved in and what kind of clients do you typically work with?

Currently, IsoForensics provides a lot of human remains testing in unidentified decedent cases. The goal is to use the isotope records contained in hair, nails, bone, and teeth to reconstruct the travel history of individuals and provide new evidence on their origins: Were they local to the area of discovery? Had they traveled prior to death? Where might they have traveled? We work with a variety of law enforcement groups in this casework.

In addition to service work, we conduct basic and applied research through funded grants and contracts. One recent project has started to investigate the origins and ages of seized elephant ivory to understand the structure of illegal trade networks in Africa and Asia.

What are some of the most common sample types you are asked to analyse, and does anything pose a particular challenge?

In any given month, we can analyze a variety of materials – human and wildlife remains, illicit drugs, explosives, etc. One of the most challenging measurements we make is for strontium isotope ratios. There is so little strontium contained in organic materials that prep work takes place in clean lab settings. The preparation of materials for radiocarbon dating is also challenging since we must be extremely careful about contamination of “old” materials with “modern” carbon. However, these challenges are worthwhile since strontium isotopes can provide potentially useful geolocation data about materials while radiocarbon dating provides quantitative information on the “age” of materials.

Are there any areas of isotopic analysis that could benefit from further research and development?

Yes. Isotope forensics benefits from better and better models/methods for interpreting data. It’s one thing to compare isotope measurement results from sample to sample or from sample to a reference databank, but it’s another thing altogether to understand the process(es) driving isotopic variation in materials. For example, are the results we observe due to differences in TNT manufacturing process? Or coca plant physiology? Or elephant diet?

Isotope analytical techniques also change over time as better instrumentation is developed. Understanding the impact of different analysis techniques on measured isotope ratios is extremely important when comparisons are made – especially in legal settings. A major focus of the field is the standardization of practices and protocols, to generate comparable results over time and space (e.g., from lab to lab).

How has the need for isotope analysis in forensic investigations changed over the years, if at all?

The forensic application of isotope analysis has been increasing the past 10-20 years. This is partly due to changes in analytical techniques, which have made isotope ratio measurements faster and cheaper. In addition, those who could benefit most from forensic isotope data–law enforcement, regulators, etc.–have become more aware of the technique and it potential usefulness in various types of investigations. We as forensic scientists and isotope analysts can do even more to spread awareness about the technique and its many applications.

Finally, do you have any advice for students hoping to pursue a career in this field of work?

Isotope analysis is one (extremely useful!) tool in a forensic scientist’s toolbox. Having a background and training in other areas–such as anthropology, analytical chemistry, biology, biochemistry, geology, law, or statistics–can be very important when applying isotope analysis techniques and interpreting the resultant data. The field of isotope forensics is relatively small compared to some other forensic disciplines, so be sure to read papers, attend meetings, and network with scientists working in the field.

Visit the Isoforensics Inc. website for more information.