title: Formation of diclofenac and sulfamethoxazole reversible transformation products in aquifer material under denitrifying conditions: batch experiments.
abstract: Soil-aquifer processes have proven to work as a natural treatment for the attenuation of numerous contaminants during artificial recharge of groundwater. Nowadays, significant scientific effort is being devoted to understanding the fate of pharmaceuticals in subsurface environments, and to verify if such semipersistent organic micropollutants could also be efficiently removed from water. In this context we carried out a series of batch experiments involving aquifer material, selected drugs (initial concentration of 1 μg/L and 1 mg/L), and denitrifying conditions. Diclofenac and sulfamethoxazole exhibited an unreported and peculiar behavior. Their concentrations consistently dropped in the middle of the tests but recovered toward the end, which suggest a complex effect of denitrifying conditions on aromatic amines. The transformation products Nitro-Diclofenac and 4-Nitro-Sulfamethoxazole were detected in the biotic experiments, while nitrite was present in the water. Their concentrations developed almost opposite to those of their respective parent compounds. We conjecture that this temporal and reversible effect of denitrifying conditions on the studied aromatic amines could have significant environmental implications, and could explain at least partially the wide range of removals in subsurface environments reported in literature for DCF and SMX, as well as some apparent discrepancies on SMX behavior.
authors.affiliation: GHS, Dept. of Geosciences, Institute of Environmental Assessment and Water Research, IDAEA-CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain. manuela.barbieri1@gmail.com
authors.forename: Manuela
authors.initials: M
authors.lastname: Barbieri
authors.forename: Jesús
authors.initials: J
authors.lastname: Carrera
authors.forename: Carlos
authors.initials: C
authors.lastname: Ayora
authors.forename: Xavier
authors.initials: X
authors.lastname: Sanchez-Vila
authors.forename: Tobias
authors.initials: T
authors.lastname: Licha
authors.forename: Karsten
authors.initials: K
authors.lastname: Nödler
authors.forename: Victoria
authors.initials: V
authors.lastname: Osorio
authors.forename: Sandra
authors.initials: S
authors.lastname: Pérez
authors.forename: Marianne
authors.initials: M
authors.lastname: Köck-Schulmeyer
authors.forename: Miren
authors.initials: M
authors.lastname: López de Alda
authors.forename: Damià
authors.initials: D
authors.lastname: Barceló
mesh_terms: D000890:Anti-Infective Agents / Q000032:analysis / Q000737:chemistry*; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000032:analysis / Q000737:chemistry*; D058440:Denitrification; D004008:Diclofenac / Q000032:analysis / Q000737:chemistry*; D060587:Groundwater / Q000737:chemistry; D008956:Models, Chemical; D013420:Sulfamethoxazole / Q000032:analysis / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D000890:Anti-Infective Agents; D000894:Anti-Inflammatory Agents, Non-Steroidal; D014874:Water Pollutants, Chemical; D004008:Diclofenac; D013420:Sulfamethoxazole