Antibiotic removal from wastewaters: the ozonation of amoxicillin

The presence of amoxicillin, a widely used antibiotic, has been documented in Sewage Treatment Plant (STP) effluents. As for other pharmaceuticals, ozonation is proposed as a process for its abatement from these effluents. The results of ozonation experiments on amoxicillin containing aqueous solutions indicate that ozone attack is mainly directed towards the phenolic ring of the studied molecule leading to the formation of hydroxyderivative intermediates. No direct evidences of attack on sulfur atom with sulfoxide formation are found. A kinetic investigation is carried out allowing the assessment of the kinetics of direct ozone attack and that of OH radicals to amoxicillin

Evaluation des risques environnementaux concernant 6 substances pharmaceutiques : les procédures de l`évaluation des risques environnementaux sont-elles suffisantes pour protéger l`écosystème aquatique ?

[Departement_IRSTEA]MA [TR1_IRSTEA]QSA / EXPERInternational audienceIn this study, acute and chronic data of 6 human pharmaceuticals (Carbamazepine, Clofibric acid, Diclofenac, Ofloxacin, Propranolol and Sulphamethoxazole) have been collected, using our own experimental data and literature data. From this data collection, the 2-tiered European draft guideline on the environmental risk assessment of such substances was tested. Firstly, measured environmental concentrations (MEC) in effluents from France and from published data obtained within effluents and surface waters in Germany were compared to the predicted environmental concentrations (PEC) respectively in both countries. Secondly, in a similar manner, using the compiled toxicity data on aquatic organisms, predicted no effect concentrations (PNEC) derived from chronic data were compared to PNEC derived from acute data. Globally, results demonstrated that (a) all environmental concentrations (predicted or measured) for each considered pharmaceutical exceeded the 10 ng/L cut-off value, which requires the second tier assessment based on ecotoxicity data, (b) the 6 pharmaceuticals showed a relatively limited acute toxicity and (c) Carbamazepine and Propranolol were inaccurately identified as having negligible risks under the current European draft procedure. Such results should help to provide further sound considerations for discussing the actual procedure on pharmaceuticals, especially on the need of appropriate ecotoxicity tests

Early diagenetic production and sediment-water exchange of fluorescent dissolved organic matter in the coastal environment

Fluorescence at wavelengths characteristic of humic substances (excitation 350 nm, emission 450 nm) have been used in this study to approximate concentrationsof fluorescent dissolved organic material (FDOM). In situ regulated and unregulated benthic chambers, sediment cores, and laboratory tank incubations were usedto study early diagenesis of FDOM in coastal marine sediments of the Gullmar Fjord, western Sweden. In the regulated in situ chambers, pH and oxygen werekept at relatively stable levels, while in the unregulated in situ chambers, pH and oxygen were left to decrease as a result of biological activity. FDOM porewaterdistributions and correlation between FDOM and parameters indicating mineralization showed that FDOM was formed in the sediment and should flux across thesediment-water interface. A substantial flux of FDOM was also observed during winter and spring conditions and during anoxic conditions fall. However, no fluxwas observed during oxic conditions fall. Modeling indicated that oxygen penetration depth was deeper during winter than during fall, i.e., the oxygen penetrationdepth increased during fall towards winter values. We suggest that as FeOOH was formed when oxygen penetration depths increased, FDOM was sorbed tonewly formed FeOOH, inhibiting FDOM flux over the sediment-water interface. In addition, at onset of anoxic conditions in the sediment surface layer in fallincubations, FDOM flux from sediment to overlying water increased substantially. Increases in anoxic FDOM fluxes were accompanied by increases in Fe andphosphate fluxes. We suggest that reductively dissolved FeOOH released sorbed FDOM. FDOM released from FeOOH by anoxic conditions was not resorbedwhen oxic conditions were resumed. This could be an effect of higher pH in overlying water as compared with porewater, inhibiting FeOOH sorption of FDOM