Tracking the invisible threat: Persistent explosive residues in raw and drinking water bodies

This study provides a comprehensive nationwide assessment of explosive residues and their degradation products in French water resources and drinking water, including mainland and overseas territories. A total of 54 target compounds were selected based on historical usage, environmental persistence, and analytical feasibility. Between 2020 and 2022, water samples from nearly 300 sites-representing resources for 20-25 % of the French population-were analyzed using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS). Explosive residues were detected in 11 % of the 797 samples, mainly in raw groundwater. Frequently identified compounds included 2,6-dinitrotoluene (2,6-DNT), diphenylamine (DPA), and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), while others appeared less often but sometimes at high levels. These contaminants were largely linked to historical battlefields and former munitions storage areas, especially in the Grand-Est region bordering Germany. Degradation products like aminodinitrotoluenes (ADNTs) were more common in drinking water, possibly due to incomplete removal or transformation during treatment. Significant correlations between DNT, nitrotoluene (NT), and perchlorate suggest a shared origin tied to historical military activity. The findings highlight the need for continued monitoring of explosive residues, not only in France but in other regions affected by historical or current military operations.