VSL at the International Conference on Mercury as a Global Pollutant


Preceding the 14th International Conference on Mercury as a Global Pollutant (ICMGP 2019) (8 – 13 September 2019, Krakow, Poland) VSL and partners host an expert workshop “Comparability of mercury measurements in air” (Sunday 7 September 2019 13:00 – 15:30). During the workshop Iris de Krom will present an overview of the latest developments in the area of traceable mercury measurements for elemental gaseous mercury in Europe. Furthermore, during the ICMGP Iris de Krom will present a poster “VSL’s novel primary mercury vapour generator versus the Dumarey equation” (Tuesday 9 September 2019) and during session 1.12 “Metrological traceability for mercury analysis and speciation” (Friday 13 September 2019 9:30-12:00) Iris de Krom will give an oral presentation titled “Comparable measurement results  for mercury concentrations in gas emission sources and the atmosphere”. For more information about ICMGP 2019 visit: https://www.mercury2019krakow.com/gb/.


Mercury is a naturally occurring element in the earth crust and it is the only metal which is liquid at room temperature, therefore it is also known as quicksilver. Currently, levels in the atmosphere are up to 5 times above natural levels. This is primarily caused by human activities, where mercury ends up in the environment. Because of its toxicity mercury poses one of the largest current threats to human, animal and environmental health across the globe. Worldwide, initiatives are taken to reduce the mercury burden on the environment, and related regulations become ever more stringent to comply with. To enable this, robust, reliable and traceable measurements of mercury are essential.

To provide traceability for mercury measurements in emission sources and in the atmosphere VSL has developed a mercury vapour generator, which can be used as a calibrator of measuring equipment. This vapour generator is directly traceable to the kilogram, the SI measurement unit of mass. Currently this is the only primary elemental mercury vapour generator in operation worldwide and as a National Metrology Institute (NMI), VSL expects this facility to play a key role in enabling the reduction of the mercury burden on the environment.


During the oral presentation at ICMGP 2019 on 13 September 2019, our colleague Iris de Krom will present the results of the full characterisation of the mercury generator, which is based on diffusion according to ISO 6145-8. As a benchmark the recent mercury measurement comparison between current calibration facilities maintained by NMIs and equipment manufacturers will be shown. This comparison made use of sorbents tubes loaded with mercury amounts ranging from 2 ng to 1000 ng.

Apart from its elemental form, mercury occurs in the environment in oxidized forms. These forms are extremely reactive and can be transformed into other species such as methylmercury, which is considered the most toxic mercury species because of its bioaccumulation in aquatic systems. Within the “Metrology for oxidised mercury” (MercOx) project, under the European Metrology Programme for Innovation and Research, VSL’s primary standard is used to establish a traceable calibration methodology for the most important oxidised mercury-containing species, especially for mercury chloride (HgCl2). A concise overview and the first results will be shown in this presentation. For more information about the MercOx project visit: http://www.mercox.si/.  


Our primary elemental mercury vapour generator is a worldwide first. Its specifications are summarized below. For information or enquiries for the calibration or certification of your mercury equipment and preparation of transfer standards in tubes: Hg@vsl.nl.


Specifications of VSL’s primary elemental mercury vapour generator



Transfer standards in tubes


0.1 – 108 ng/l

2 – 1000 ng

Uncertainty (k = 2)

3.0 – 2.2 %

3.1 – 2.5 %