TY - JOUR IS - 3 KW - field trials KW - oxo-degradable KW - oxo-biodegradable KW - PAS 9017 KW - pro-oxidants KW - microplastics AV - public JF - Royal Society Open Science SN - 2054-5703 ID - discovery10206653 EP - 17 N2 - Pro-oxidant additive containing (PAC) plastics are designed to degrade in the unmanaged natural environment through oxidation and biological processes. In 2020, the British Standard Institution published the PAS 9017:2020 standard designed to ensure that PAC plastic tested under a specific set of protocols would successfully biodegrade in the environment. In this article, we compare the outcomes of laboratory tests carried out according to PAS 9017:2020 with field tests in an open unmanaged environment in the UK over 24 months. We report that the PAC cups were intact after 24 months and did not undergo significant abiotic degradation nor biodegradation during field tests. The PAC cups did undergo rapid abiotic degradation during accelerated UV laboratory tests, however the carbonyl index never reached 1.0. The molecular weight of the PAC cups decreased throughout the field trials and during the laboratory tests but neither satisfied the requirements stated in PAS 9017:2020. Earthworm avoidance tests and earthworm reproduction tests carried out in artificial soil showed no significant adverse effects or impact on the microbial community. We conclude that PAS 9017:2020 does not predict the real-world behaviour of the PAC plastics we tested in the open unmanaged environment in the temperate climate of the UK. VL - 12 UR - https://doi.org/10.1098/rsos.241270 A1 - Sciscione, Fabiola A1 - Prout, Luba A1 - Jeffries, Jack WE A1 - Karam, Hajar J A1 - Constantinou, Achilleas A1 - Peng, Fei A1 - Al-Salem, SM A1 - Hailes, Helen C A1 - Miodownik, Mark Y1 - 2025/03/12/ TI - Comparison of the behaviour of pro-oxidant additive containing plastic degradation in the unmanaged natural environment and in the laboratory N1 - © 2025 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited. PB - ROYAL SOC ER -