Grönroos, PäiviKoivikko, RiittaSarkkinen, MikaTervonen, KeijoLanteri, SariVäisänen, RitvaIlmakunnas, Markku2024-06-112024-06-112024978-952-11-5684-7http://hdl.handle.net/10138/576771Proftest Syke carried out the proficiency test (PT) for analysis of alkalinity, conductivity, nutrients, and pH in natural waters in February-March 2024. In total, there were 32 participants in the PT. Either the calculated concentration or the robust mean, the mean or the median of the reported results was used as the assigned values for the measurands. The overall performance of the participants was eval-uated by using z scores. In this PT 90 % of the results were satisfactory when total deviation of 0.2 pH units for pH values and 5–25 % for the other measurands was accepted from the assigned value. Warm thanks to all participants in this proficiency test!engIn Copyright 1.0KirjaURN:ISBN:978-952-11-5684-7