Suspect and non-target screening of contaminants of emerging concern in Norwegian biogas digestates

To achieve a circular bioeconomy, nutrients within residues such as food waste (FW) and sewage sludge (SS) must be recycled to e.g., food production. However, these biowastes often contain numerous contaminants which are recycled alongside the nutrients. Identifying these contaminants is crucial to prevent potential harmful effects when residues from circular processes, including biogas digestates, are utilized as fertilizers or soil amendments in agriculture. In this study, suspect and nontarget screening was used to comprehensively assess contaminants of emerging concern (CECs) and their transformation products (TPs) in biogas digestates derived from FW and SS. A total of 133 CECs and five TPs were tentatively identified, including 61 pharmaceuticals and personal care products (PPCPs), eight pesticides, and 64 industrial chemicals, with 44 of these CECs confirmed using analytical standards. Concentrations ranged from low μg kg −1 dry matter (DM) to several hundred mg kg −1 DM. SS based digestates were found to be more heavily contaminated with industrial chemicals and PPCPs, while FW based digestates contained higher levels of pesticides. These findings highlight the importance of stringent contaminant surveillance to ensure the safe agricultural application of biogas digestates and to mitigate potential risks associated with the recycling of organic residues. • Identified 133 emerging contaminants and 5 transformation products in digestates. • Concentrations ranged from low μg kg −1 DM to several hundred mg kg −1 DM. • Sewage sludge digestates had more industrial chemicals and PPCPs than food waste. • Food waste digestates contained higher pesticide levels than sewage sludge.