|Julkaisusarja ja numero:||25/2018|| |
|Tekijät:||Maunuksela, Liisa; Pelkonen, Aija; Björklöf, Katarina; Ilmakunnas, Markku; Kartio, Mirja; Leivuori, Mirja|| |
Evira and Proftest SYKE carried out this interlaboratory comparison in May 2018 for assessing phytotoxicity, chemical composition and maturity of green waste and sewage sludge compost samples. In total 11 participants took part. Participants measured altogether 14 measurands, which are used for determining composition, phytotoxicity, stability and maturity of soil improvers, caused for instance by ammonia, ethylene oxide or short chain fatty acids. The mean of the results reported by the participants was chosen to be the assigned value for the measurands. The performance of the participants was evaluated by using z scores. In this interlaboratory comparison, 96 % of the results were satisfactory when deviation of 1 pH units and 25–80 % (for other measurands) from the assigned value was accepted. According to the results, many participants have good practices and manage these analyses well. Some participants still need more experience. More detailed guidance on procedures that may affect the results is needed.
Warm thanks to all the participants of this interlaboratory comparison!