Formation of diclofenac and sulfamethoxazole reversible transformation products in aquifer material under denitrifying conditions: Batch experiments

• DOI: 10.1016/j.scitotenv.2012.02.058
• Publication Date: 2012-04-23T11:50:44Z
• Authors: Manuela Barbieri; Jesús Carrera; Carlos Ayora; Xavier Sanchez-Vila; Tobias Licha; Karsten Nödler; Victoria Osorio; Sandra Pérez; Marianne Köck-Sch...; Miren López de Alda; Damià Barceló
• Keywords: 2. Zero hunger; Engineering, Civil; Diclofenac; Sulfamethoxazole; Anti-Inflammatory Agents, Non-Steroidal; 0207 environmental engineering; Engineering, Multidisciplinary; 02 engineering and technology; Computer Science, Software Engineering; 01 natural sciences; Engineering, Marine; 6. Clean water; Engineering, Manufacturing; Engineering, Mechanical; Anti-Infective Agents; Models, Chemical; Engineering, Industrial; Denitrification; Engineering, Ocean; Engineering, Aerospace; Engineering, Biomedical; Groundwater; Water Pollutants, Chemical; 0105 earth and related environmental sciences

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.