title: Environmental occurrence, fate and transformation of benzodiazepines in water treatment.
abstract: Benzodiazepine derivatives are prescribed in large quantities globally and are potentially new emerging environmental contaminants. Unfortunately, a dearth of data exists concerning occurrence, persistence and fate in the environment. This paper redresses this by reviewing existing literature, assessing the occurrence of selected benzodiazepine anxiolytics (diazepam, oxazepam and bromazepam) in wastewater influent and effluent and surface water from Slovenia, evaluating their removal during water treatment and identifying the transformation products formed during water treatment. Their occurrence was monitored in hospital effluent, river water and in wastewater treatment plant influent and effluent. The study reveals the presence of benzodiazepine derivatives in all samples with the highest amounts in hospital effluents: 111 ng L(-1), 158 ng L(-1) and 72 ng L(-1) for diazepam, bromazepam and oxazepam, respectively. Removal efficiencies with respect to biological treatment of diazepam were 16-18% (oxic), 18-32% (anoxic→oxic), 53-76% (oxic→anoxic) and 83% (oxic→anoxic→oxic→anoxic cascade bioreactors), while the removal oxazepam was 20-24% under anoxic conditions. Coupled biological and photochemical treatment followed by the adsorption to activated carbon resulted in a removal efficiency of 99.99%. Results reveal the recalcitrant nature of benzodiazepine derivatives and suggest that only combinational treatment is sufficient to remove them. In addition, eight novel diazepam and four novel oxazepam transformation products are reported.
authors: Jožef Stefan Institute, Department of Environmental Sciences, Ljubljana, Slovenia.
authors: T
authors: T
authors: Kosjek
authors: S
authors: S
authors: Perko
authors: M
authors: M
authors: Zupanc
authors: M
authors: M
authors: Zanoški Hren
authors: T
authors: T
authors: Landeka Dragičević
authors: D
authors: D
authors: Zigon
authors: B
authors: B
authors: Kompare
authors: E
authors: E
authors: Heath
mesh_terms: D001569:Benzodiazepines / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D001673:Biodegradation, Environmental; D019149:Bioreactors; D001960:Bromazepam / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D002849:Chromatography, Gas / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D003975:Diazepam / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D010076:Oxazepam / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D010865:Pilot Projects; D017524:Slovenia; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*
chemical_list: D014874:Water Pollutants, Chemical; D001569:Benzodiazepines; D010076:Oxazepam; D003975:Diazepam; D001960:Bromazepam