2026-10-13T03:45:09Z https://api.figshare.com/v2/oai

oai:figshare.com:article/34027394 2026-09-29T19:07:16Z category_4 category_8 category_15 category_272 category_39 category_61 category_64 category_132 category_134 portal_63 item_type_6 month_year_09_2026

Nitrogen-Centered Persistent Free Radicals from Roxarsone Phototransformation on Soil Minerals: Magnetic Coupling Mechanism and PFR-Driven Ecological Risks Hongke Feng (25138643) Yuyue Li (22123886) Fuxuan Ren (25138646) Xingzhi Jin (11796942) Xiaohu Zhang (391063) Yi Yang (116183) Hao Chen (5190) Peng Cai (1423345) Xing Ding (1803007) Biochemistry Microbiology Neuroscience Environmental Sciences not elsewhere classified Ecology Developmental Biology Cancer Infectious Diseases Virology previously unrecognized pathway persistent free radicals peak epr signature observed growth inhibition mediated processes rather environmental risk assessments efficient electron shuttles centered radicals act multitrophic toxicity tests soil mineral surfaces released inorganic arsenic centered radical formation magnetic coupling mechanism 3 </ sub 2 </ sub suppressing pfr stability magnetic coupling incorporating radical driven toxicity soil minerals soil environments rigorous arsenic arsenic contamination centered pfrs species exhibit roxarsone phototransformation recognized source predominantly driven oxidative damage overlooked hazard organoarsenic contaminants histopathological effects findings uncover distinct triple controlled conditions concurrent evolution bond cleavage Roxarsone (ROX) degradation in soil environments is a recognized source of arsenic contamination, but the concurrent evolution of persistent free radicals (PFRs) presents an overlooked hazard. Here, we report the generation of unique nitrogen-centered PFRs during ROX phototransformation on soil mineral surfaces. Unlike typical environmental PFRs, these species exhibit a distinct triple-peak EPR signature, which is proposed to arise from the magnetic coupling between •NO and •NHR radicals following C–As bond cleavage. Mineral composition strongly governs radical evolution, with MnO₂ enhancing and Fe₂O₃ suppressing PFR stability. These nitrogen-centered radicals act as efficient electron shuttles, sustaining the production of reactive oxygen species (•OH, •O₂^–, H₂O₂). Multitrophic toxicity tests (bacteria-plant-earthworm) combined with rigorous arsenic-controlled conditions (As(V)≤150 ppb, As(III)≤20 ppb) reveal that the observed growth inhibition, oxidative damage, and histopathological effects are predominantly driven by PFR-mediated processes rather than by released inorganic arsenic. These findings uncover a previously unrecognized pathway for nitrogen-centered radical formation and highlight the necessity of incorporating radical-driven toxicity into environmental risk assessments of organoarsenic contaminants. 2026-09-29T00:00:00Z Text Journal contribution 10.1021/acs.est.6c04908.s001 https://figshare.com/articles/journal_contribution/Nitrogen-Centered_Persistent_Free_Radicals_from_Roxarsone_Phototransformation_on_Soil_Minerals_Magnetic_Coupling_Mechanism_and_PFR-Driven_Ecological_Risks/34027394 CC BY-NC 4.0