Bjedov_2026_Environ.Pollut__128601

Residues from industrial hemp seed oil production are increasingly explored for agricultural and biorefinery applications, yet their ecological compatibility with soil organisms remains poorly understood. This study investigated the effects of non-fermented and fermented hemp pomace (3 and 10 days, Thermomyces lanuginosus) on biochemical and behavioural responses in the earthworm Eisenia andrei following 48 h exposure to soils amended with different proportions of the substrates. Neurotoxicity (acetylcholinesterase [AChE]), detoxification pathways (carboxylesterase [CES], glutathione S-transferase [GST], multixenobiotic resistance [MXR]), oxidative stress responses (catalase [CAT], reduced glutathione [GSH], reactive oxygen species [ROS]), and avoidance behaviour were evaluated. Exposure to both non-fermented and fermented hemp pomaces showed alterations in the neurotoxicity- and detoxification-related biomarker responses, which were treatment-dependent, with the strongest effects observed in the non-fermented treatment. In contrast, there was lack of consistent oxidative stress responses. In parallel, earthworms strongly avoided soils amended with both non-fermented and fermented hemp pomace, indicating clear substrate incompatibility. These findings show that both non-fermented and fermented hemp pomace are chemically complex and biologically active organic materials rather than inert soil amendments. Behavioural responses, together with selected neurotoxicity and detoxification biomarkers, proved more sensitive than oxidative stress endpoints. Overall, the study highlights the importance of using integrated bioassays when assessing the environmental compatibility of agro-industrial residues intended for soil application.