Monitoring military facilities for agent storage and disposal
There has long been a need to monitor military facilities for storing and disposing of the historic stockpiles of chemical warfare agents (CWAs).
As well as the stockpiles themselves, remediation of ‘non-stockpile’ materials and equipment (‘materiel’) is also a focus of attention. This includes bombs, projectiles and rockets containing CWAs, buried or recovered sources of CWAs, as well as contaminated materials, land and buildings.
This issue came to the fore in April 1997 with the entering into force of the Chemical Weapons Convention (CWC), which in turn reaffirms provisions made under the Geneva Protocol of 1925 for the “prohibition of the use in war of asphyxiating, poisonous or other gases, and of bacteriological methods of warfare”.
The CWC aims to completely eliminate the possibility of chemical weapons being used, and covers about 70 toxic chemicals, split into three categories (‘schedules’):
- Schedule 1 includes chemical warfare agents – including sarin (GB), soman (GD), tabun (GA), VX, mustards (HD and HN), and the Lewisites.
- Schedule 2 lists simulants and precursors to chemicals in Schedule 1.
- Schedule 3 covers chemicals with large-scale legitimate commercial uses.
The Organisation for the Prohibition of Chemical Weapons (OPCW) is responsible for implementing the CWC, which to date has been ratified by 189 states worldwide. In order to be accredited by the OPCW, laboratories need to have obtained satisfactory results in the analysis of control samples, as well as to perform well in inter-laboratory proficiency tests and to have established an internationally recognised quality assurance system.
Markes’ technology is now used by OPCW-accredited laboratories at military establishments, homeland defence organisations and CWA research facilities worldwide.
What Markes can offer
A number of military (and some civilian) applications have for many years used the Depot Area Air Monitoring System (DAAMS) to monitor airborne CWAs.
This employs metal or glass sorbent-packed tubes, with those for high-flow applications having a wider bore.
Sampling onto DAAMS tubes is typically carried out over 6–24 hours, with off-line analysis by thermal desorption (TD). Markes supplies instruments and accessories suitable for a range of DAAMS applications.
The very low concentrations at which many chemical agents are toxic presents a challenge for many analytical systems, exacerbated by the need for rapid detection in order to minimise harm when an incident occurs.
Fortunately, however, many nerve agents and other hazardous compounds are amenable to pre-concentration by thermal desorption, and Markes’ systems are compatible with even the most challenging trace-level compounds within the schedules of the CWC (such as free-VX).
Two TD sampling protocols are typically used for monitoring of CWA stockpiles:
- Near-real-time monitoring: Because of the need to rapidly alert military personnel to incidents involving CWAs, near-real-time (NRT) monitoring is an absolute requirement at military-stockpile sites or demilitarisation (‘demil’) facilities. Markes’ TT24-7 is a dedicated system for NRT monitoring, suitable for conventional laboratories as well as more challenging situations such as remote sites or mobile laboratories. When used with fast GC, responses can be achieved within a matter of minutes.
- Off-line monitoring: Off-line pumped-tube sampling onto TD tubes (e.g. DAAMS tubes) is a very useful technique for confirmatory analysis, and for sampling larger volumes (which allows detection limits to be reduced to 'general population limit' levels). The UNITY-xr system is an ideal TD platform for analysing single tubes, while the ULTRA-xr, and TD100-xr systems allow automated multi-tube analysis.
- For more background to chemical warfare agents and the analytical challenge they pose, see: T. Murphy, G. Roberts and G. Davies, Chemical warfare agents and use of thermal desorption-GC-MS to achieve improved trace-level detection, Spectroscopy, April 2009.
- For an example of the detection of CWA simulants with an analytical setup using the TT24-7, fast GC and BenchTOF-dx time-of-flight mass spectrometer, see: J. Leppert, G. Horner, F. Rietz, J. Ringer, P. Schulze Lammers and P. Boeker, Near real time detection of hazardous airborne substances, Talanta, 2012, 101: 440–446.
- For examples of the use of thermal desorption to analyse trace-level high-boiling compounds with similar characteristics to many CWAs, see Application Notes 034 and 039.
- For more detail on the detection of free-VX using thermal desorption, see Application Note 044.
- For information on the detection of trace-level chemical agents in air, see Application Note 063.