About Wepal / Quasimeme

Since 1956, WEPAL organises proficiency tests in the terrestrial field, while QUASIMEME started in 1992 as a supplier of proficiency tests in the marine environment. In January 2011, the activities of WEPAL and QUASIMEME have been merged resulting in WEPAL/QUASIMEME.


WEPAL/QUASIMEME is accredited for the organisation of Interlaboratory Studies by the Dutch Accreditation Council RvA since April 26, 2000 (registration number R002). The accreditation is based on the ISO 17043 requirements. The accreditation covers the quality system of the organisation as well as the determinand groups mentioned on the website of the RvA. Detailed information about the determinands in the determinand groups see detailed scope [interne link ‘Determinands...’].

Within WEPAL/QUASIMEME, WEPAL covers proficiency tests related to the terrestrial environment (e.g. soil, plants, manure, compost and biomass) and freshwater sediment. QUASIMEME organises proficiency tests for compounds and matrices in the marine environment (e.g. sea water, marine sediment, biota and shellfish toxins).

Nowadays, three groups of Wageningen University & Research are involved in the organisation of WEPAL/QUASIMEME:

WEPAL/QUASIMEME provides more than proficiency-testing schemes. At its core is a holistic learning by doing spiral. The routine laboratory performance studies provide the basis of external quality assurance for institutes that make regular chemical measurements in the terrestrial, aquatic and/or marine environment.

Participants may use the results of the proficiency tests to:

  • Validate internal laboratory QA;
  • Improve methodology;
  • Support accreditation;
  • Support QA of environmental monitoring data;
  • Provide data for national or international programmes.

In addition, WEPAL/QUASIMEME provides:

  • Development exercises for e.g. emergent pollutants or in case of problems with analytical methodology;
  • Workshops for discussion and improvement in methodology;
  • A Helpdesk, which is supported by experts in the field.
  • Newsletters and conferences.

WEPAL/QUASIMEME has for the terrestrial and the marine components each a Scientific Advisory Board, with experts in the field who support the organisation and represent the participants. The Organisation is compliant to ISO17043, ISO9000 and ISO14001.

WEPAL/QUASIMEME is an interactive scheme. Participants can request specific determinands and matrices for inclusion in the programme, and make suggestions for development exercises and workshop topics for e.g. emergent pollutants.

In 2016, WEPAL/QUASIMEME celebrated its fifth anniversary together with 60 years of WEPAL and 25 years of QUASIMEME. A joint logo was presented to reinforce the collaboration.

History WEPAL

In the early 1950s, there was regular contact between representatives of the various agricultural research institutions in the Netherlands with Prof. Dr. A.C. Schuffelen, professor of Soil Chemistry at the then Agricultural College. The subject of discussion included the comparability of results of inorganic chemical research of dried and ground agricultural crop samples. In 1956 it was decided to organize a ring test in which the participating laboratories would analyse representative sub-samples of dried and ground crop material from mainly agricultural crops for concentrations of nutrients.


Ring tests: principles and effect

The participating laboratories were sent six different dried and ground crop samples every two months. The laboratories reported their results under a code name. All results were summarized and an average value calculated. Laboratories with abnormal results were marked with one or two stars. Each participant could therefore compare his values with these averages and possibly take measures if deviating values were found. This ring test was thus an instrument for continuous quality control of the participating laboratories. A progressive initiative for that time. Representatives of the Dutch research institutions united in the so-called “Contact Group for Analysts” met at least once a year to discuss, among other things, the results of the ring tests. In addition, this organization also resulted in participants often asking the organizer for help with analytical problems encountered.

Growth and internationalization

Due to the national and international contacts of the participating institutions, there was soon much more interest from other national and international institutions. The organization was a great success, partly due to the fact that there were no costs involved. After about 20 years, there were already around 200 participants from all over the world. At the time, the organization was quite time consuming. The crop samples had to be dried at 105 degrees Celsius and grinded. Subsequently, after intensive mixing, divided into representative sub-samples which were packed in plastic bags and then sent. There were hardly any computers at the time, which meant that all results were typed on stencils and averages and deviations were manually calculated and stars added to the individual observations. The results were then sent to all participants.

Via a subsidy provided by NUFFIC, a computer could be purchased and software developed to simplify the administration, the calculations and reporting. The ring study of crop samples was given the name IPE (International Plant-analytical Exchange) and with the help of a recognizable logo the reporting soon looked a bit more professional.

A repeated grant application was refused by NUFFIC and it was suggested that the participants pay a contribution for this form of quality control of their laboratory. This was accepted without problems by the participating laboratories. This made it easier to run the organization without having to rely on financial support (labor, printing, postage, etc.) from the now Agricultural University of Wageningen.

Extension of the ring test

Due to this financial independence, the idea arose to start an exchange study for dried (40 degrees Celsius) and grinded soil samples. After a survey among IPE participants whether there was sufficient interest, this was started in 1988. Although the logistics organization was not too complicated, reporting results was a huge problem. For soil, in addition to total contents, soil characteristics (e.g. organic matter, acidity and clay content) and availability determinations (for fertilization advice and soil contamination) are very important. What makes the whole complex is that there was a separate method for each type, while different methodologies are used for each country. The results of this ISE (International Soil-analytical Exchange) program were also discussed annually within the Contact Group for Analysts.

In collaboration with the IVM (Netherlands Institute for Environmental Issues in Amsterdam), a proficiency test for organic parameters in sediments called SETOC (Sediment Exchange for Tests of Organic Components) was started in 1990. In this proficiency test parameters such as PAHs, PCBs and organochlorine compounds were reported.

And in 1994, at the request of a Swiss research institute in Bern-Liebefeld, a fourth proficiency test was started for the verification of analytical results in dried and grinded waste products (including manure) in use in agriculture. This program was named MARSEP (Manure and Refuse-Sample Exchange Program).

The number of participants in IPE and ISE grew steadily to hundreds of participants from all over the world. Crucial in these proficiency tests is of course the quality of the soil and crop samples sent. The division of large quantities of material into shippable batches was very laborious and extreme care had to be taken to ensure the homogeneity of the shipped materials. To improve this process, after an extensive study, two devices were developed that could automatically distribute large and small portions of dried and ground soil and crop into workable and controllable quantities.

Over time, an interesting overview was obtained of the chemical composition of a wide variety of different crop and soil samples. And an additional advantage for the participating organizations was that remnants of materials already sent could be sold as internal reference material with known levels and known ranges of the standard levels.

Quality assurance

Participation in ring tests became part of the quality control of the laboratories and a standard was developed by the NEN (Dutch Standardization Institute) and later internationally by the ISO to which organizers of ring tests had to comply.

Dirkje van Dijk was appointed as quality officer and a detailed description of all actions summarized in a quality manual was started. On April 26, 2000, this led to national and international approval and recognition as an institution for organizing proficiency tests in the field of soil and crop samples by the Accreditation Council (RvA) in the Netherlands.

Further professionalizing

In 1999 Dirkje van Dijk became the head of WEPAL. By now WEPAL had four programs and around 800 participants, which made processing the results very time consuming. The WEPAL Data Entry program was developed, with which the participants could submit their results via the Internet, which could be directly read into the database. Besides the time savings and because input errors were prevented, this was also a huge quality improvement.

In 2002 Dirkje was succeeded by Bram Eijgenraam, from the BLGG (Industrial Laboratory for Soil and Crop Research). He was in charge of the laboratory and was responsible for a small-scale ring trial in the field of animal nutrition. At that time, the WEPAL software was still written in DOS and in dire need of updating. Bram was mainly involved in the development of the WEPAL software. This software was implemented in 2005. Currently everything is stored in a database and the membership and sample administration is highly automated.

Collaboration with QUASIMEME

That same year (2005) QUASIMEME came to Wageningen for proficiency tests in the field of everything that has to do with the sea and the ocean and was transferred to Alterra (currently Wageningen Environmental Research). QUASIMEME originated from an EU project that started in 1992 and had its own history (see below). Both proficiency test providers could learn a lot from each other. In 2009, for example, the statistics were developed by Wim Cofino, which are already in use by QUASIMEME was implemented in the WEPAL programmes. The collaboration with QUASIMEME became more intensive. Both organizations had few staff, so continuity could be a problem. That is why it was decided in 2011 to merge the proficiency tests. From that time on, hard work has been done to ensure continuity for both groups. In 2014 Bram Eijgenraam was succeeded by Winnie van Vark.


QUASIMEME originated in the eighties. The pollution status of the North Sea and the Baltic Sea became an important item on the international agenda. European marine monitoring programmes were developed and coordinated within the Oslo and Paris Commission (OSPAR) and the Helsinki Commission (HELCOM), with substantial support from the International Council for Exploration of the Sea (ICES).

Quasimeme monsters en rapport.JPG

Poorly comparable laboratory results

Between 1980 and 1989, international collaboration in a series of interlaboratory studies conducted under auspices of ICES and through international assessments of the environmental quality of the North sea and Baltic sea (e.g. ICES,1988) revealed time and again that laboratory results were poorly comparable and that the monitoring programs needed to be improved.
Strategies to improve the quality of the North Sea environment including monitoring were discussed at the Second North Sea Ministerial Conference in London in 1987, and led to the creation of the North Sea Task Force (NSTF). The NSTF was responsible for increasing scientific knowledge and understanding of the North Sea and made inter alia a monitoring master plan for the North Sea.

Establishment QUASIMEME

In 1989, a NSTF workshop was organised in London with a separate session for quality assurance, led by the Dutch Public Works Department (Rijkswaterstaat). One of the results of the workshop was that the NSTF formally asked the EC Measurements and Testing programme to support an ambitious Quality Assurance programme. The EC agreed and QUASIMEME was established blending the experience with quality improvement of the (former) EC Community Bureau of Reference (BCR) and that of the Marine Chemistry Working Group of ICES. The EC Measurements and Testing programme (BCR), ICES, Rijkswaterstaat and the FRS Marine Laboratory in Aberdeen, United Kingdom agreed that the latter would take the lead and host the QUASIMEME project office.

Holistic quality assurance programme

QUASIMEME was designed as an holistic quality assurance programme for marine environmental monitoring information in Europe. As a result of this pioneering project a marine network and laboratory performance studies have been established for most of the determinands measured in the marine environmental programmes for both monitoring and research purposes.
The project received funding from the EC Measurements and Testing programme in 1992 to 1996 and continued thereafter on a subscription basis making it possible for any laboratory in the world to participate. The subscription scheme includes the matrix-determinand combinations from the EU QUASIMEME 92-96 programme and has added new determinands and matrices if there is a demand. In addition, workshops and development exercises are organised with the framework of the scheme.

Transfer to Wageningen

In 2004 the project manager in Aberdeen, Dr David Wells, retired and approached Dr Wim Cofino at Wageningen University & Research to take over. The transfer of the QUASIMEME project office from Aberdeen to Wageningen was accomplished in 2005.

Within Wageningen University & Research Centre, QUASIMEME is embedded in the team ”Environmental Risk Assessment” of Wageningen Environmental Research. QUASIMEME collaborates in a structural manner with Wageningen Marine Research and on a case by case basis with Wageningen Food Safety Research and Biometris.

International support

QUASIMEME operates as a not-for-profit network organisation. Several institutes provide samples and advice regarding analytical methodology and the design of the scheme. These institutes include:

Scientific Advisory Board

QUASIMEME has a Scientific Advisory Board which is comprised of experts in each of the main areas of the QUASIMEME Laboratory Performance (LP) studies and of representatives of different groups of stakeholders in the programme.

International contacts

QUASIMEME maintains contacts with varying intensity with the following organisations in order to optimize its portfolio of services:

  • Helsinki Commission (HELCOM);
  • Oslo and Paris Commissions (OSPAR);
  • Mediterranean Pollution Monitoring and Research Programme (MEDPOL) - Barcelona Convention;
  • Arctic Monitoring and Assessment Programme (AMAP);
  • International Council for the Exploration of the Seas (ICES);
  • European Environment Agency (EEA);
  • National Marine Monitoring Programmes of member countries;
  • NORMAN: network of reference laboratories, research centres and related organisations for monitoring of emerging environmental substances. QUASIMEME is one of the founding members of the Norman network, which has been established as a continuation of an EU project. Among others, Norman has the objective to encourage the validation and harmonization of common measurement methods and monitoring tools so that the demands of risk assessors can be better met;
  • United Kingdom National Marine Chemistry Advisory Group (UK NMCAG).