RT null T1 Results and Conclusions from the 3rd Interlaboratory Assessment and Status of the 4th Interlaboratory Assessment A2 Fiedler, Heidelore A2 van der Veen, Ike A2 de Boer, Jacob K1 persistent organic pollutant YR 2018 FD 2018 LK https://wedocs.unep.org/handle/20.500.11822/26194 UL https://wedocs.unep.org/handle/20.500.11822/26194 DS UN Environment Document Repository RD Sep 19, 2026