Sign up for NPL updates
Sign up for NPL updates

Receive regular emails from NPL to get a glimpse of our activities and see how our experts are informing and influencing scientific debate

Radioactivity services

Environmental proficiency test exercise

For laboratories measuring radioactivity

What is the Environmental Radioactivity Proficiency Test Exercise?

Proficiency Testing assesses a laboratory’s performance at carrying out a measurement. Regular Proficiency Testing provides evidence of the quality of a laboratory’s measurement capabilities. Accreditation bodies consider participation in Proficiency Testing a demonstration of a laboratory’s commitment to quality. Proficiency testing also provides an opportunity to:

  • Test, validate and compare measurement schemes;
  • Evaluate performance characteristics of a method;
  • Provide confidence to customers in the quality of results;
  • Identify measurement issues and improve overall accuracy;

NPL produces a range of proficiency test items. Recent exercises have included aqueous samples containing a mixture of alpha, beta, and gamma emitters at activity concentration relevant to environmental applications*. NPL is also working towards producing solid matrixes; assigned values may be based on a consensus value or be assigned by NPL. Laboratories choose which sample types apply to their measurement capabilities. Participants in the exercise are from various industries including, Construction, Nuclear, Radiation protection, Pharmaceuticals as well as Research and Academia.

NPL dispatches the proficiency test items to participants, who have approximately four months to measure them and submit the results to us. NPL compiles an anonymised exercise report and provides feedback to the laboratories on their performance. The exercise is accredited to ISO 17043 and run on an annual basis by NPL.

If you would like to find out how you can join the next Environmental PTE, please contact us via the button below.

PT Item Name


Example radionuclides

Alpha Beta

Alpha and Beta emitters (1-20 Bq g−1) in 20 g 2 M HNO3 (with carriers)

3H, 63Ni, 90Sr, 239Pu, 241Am, and 244Cm


Alpha emitters (5-100 Bq kg−1) in 500 g 2 M HNO3 (with carriers)

243Am, 241Am, 238U, 236U, 235U,234U, and 232Th


Beta emitters (0.1-2 Bq g−1) in 500 g 0.01 M NaOH (with carriers)

3H, 14C, 36Cl, 99Tc, and 129I

Gamma High

Gamma emitters (1-50 Bq g−1) in 100 g 1 M HNO3 (with carriers)

54Mn, 60Co, 65Zn, 133Ba, 134Cs, 137Cs, and 154Eu

Gamma Low

Gamma emitters (1-50 Bq kg−1) in 100 g 1 M HNO3 (with carriers)

60Co, 85Sr, 134Cs, 137Cs, 210Pb, and241Am

How to Participate

Upcoming exercise (2024)

An invitation letter for the 2024 exercise will be circulated to past participants’ and those who have registered their interest. An invitation to participate will be circulated in summer 2024. If you would like to register interest for future exercises, please email

Current exercise (2023)

The 2023 Environmental Radioactivity Proficiency Test Exercise (PTE 2023) is underway. Samples are due to be despatched early 2024. Details of the sample types available, timelines and cost are detailed in the invitation letter linked below. The sample information and reporting letter provides information related to reporting. If you have participated in this exercise, please send your results to using the reporting and techniques forms below.

Invitation Letter

Sample Information & Reporting

Reporting Form

Techniques Form

Past exercise and reports

The 2022 Environmental Radioactivity Proficiency Test Exercise (PTE 2022) is now complete and the final report has been reissued NPL Report IR65. Please note that reports on previous exercises are also available here.

Contact us

For questions, queries and comments relating to the Environmental PTE scheme please contact us. 


NPL also provide radioactive standards, calibrations and consultation. For information related to this or discuss your requirements please contact us

Contact us

Find out more about our Standard radionuclide solutions

Work with us

Our research and measurement solutions support innovation and product development. We work with companies to deliver business advantage and commercial success.
Contact our Customer Services team on +44 20 8943 7070