WICO 2016 International Water Isotope Inter-Comparison Test

The Isotope Hydrology Laboratory of the International Atomic Energy Agency (IAEA) is pleased to announce the 2016 water isotope inter-comparison for international laboratory performance assessment of deuterium (2H) and oxygen isotope (18O) assays of natural waters, conducted by all isotope-ratio mass spectrometry and laser spectrometry methods. Laboratories will benefit from participation in this test by i) identification of potential performance areas identified through individualized lab testing scores, and ii) through the collective analysis of combined participant results, which may help to inform improved water isotope analyses by all types of instrumental measurement technologies.

Core Test Samples

Participants will receive one core set of WICO 2016 test water samples. The core set includes 5 natural waters (30 mL each) spanning the predominant isotopic range of terrestrial surface waters; between 0/0 and -25/-170 permil for 18O/2H, respectively, relative to VSMOW.

All test samples are to be measured by dual-inlet or continuous-flow isotope-ratio mass spectrometry and/or by laser spectrometry using each participant's routine isotopic measurement methodologies and data normalization procedures, using their own laboratory calibration standards. Sufficient replicated analyses of each WICO test sample (e.g. n>5) are encouraged.

Optional Test Samples

Participants may select from 3 optional test water samples, as deemed appropriate for their analytical needs. These include an isotopically enriched, depleted, and a high salinity (TDS) sample.


WICO 2016 samples will be shipped starting in February 2016. An electronic Results Reporting Form and a confidential Laboratory ID code will be provided to each participant along with the test water samples.

Reporting Deadline: laboratories are expected to report their final WICO 2016 test 18O and 2H results by June 30, 2016.

Reports to Participants

Based on the submitted results, the IAEA will send a confidential scoring report to each participant by September, 2016; an inclusive synthesis report and general recommendations will follow thereafter, in order to allow for participant feedback. To ensure confidentiality, all participating laboratories will be anonymous in all WICO related reports or publications. A WICO 2016 participation and completion certificate may be provided upon request for laboratory accreditation purposes.


The person materially responsible for receipt, analysis, and final reporting of WICO test results to the IAEA should complete the registration form. The IAEA will cover the shipping cost of WICO samples to the participant's laboratory. Only one registration per laboratory please! Register Here


For more information or other enquiries, please email the WICO Team

Responsible/Contact: Isotope Hydrology Section | Last update: 07 January 2016