title: Long-Term Persistence of an Anxiolytic Drug (Oxazepam) in a Large Freshwater Lake.
abstract: Production and human consumption of pharmaceuticals result in contamination of surface waters worldwide. Little is known about the long-term (i.e., over decades) fate of pharmaceuticals in aquatic systems. Here, we show that the most prescribed anxiolytic in Sweden (oxazepam) persists in its therapeutic form for several decades after being deposited in a large freshwater lake. By comparing sediment cores collected in 1995 and 2013, we demonstrate that oxazepam inputs from the early 1970s remained in the sediments until sampling in 2013, despite in situ degradation processes and sediment diagenesis. In laboratory and pond experiments, we further reveal that therapeutic forms of oxazepam can persist over several months in cold (5 °C) lake water free from UV light. We conclude that oxazepam can persist in lakes over a time scale much longer than previously realized and that levels can build up in lakes due to both a legacy of past inputs and a growing urban population.
authors.affiliation: Department of Ecology and Environmental Science, Umeå University , 90187 Umeå, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Klaminder
authors.affiliation: Department of Ecology and Environmental Science, Umeå University , 90187 Umeå, Sweden.
authors.forename: T
authors.initials: T
authors.lastname: Brodin
authors.affiliation: Department of Ecology and Environmental Science, Umeå University , 90187 Umeå, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Sundelin
authors.affiliation: Department of Geography, Loughborough University , LE11 3TU Leicestershire, U.K.
authors.forename: N J
authors.initials: NJ
authors.lastname: Anderson
authors.affiliation: Department of Ecology and Environmental Science, Umeå University , 90187 Umeå, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Fahlman
authors.affiliation: Department of Ecology and Environmental Science, Umeå University , 90187 Umeå, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Jonsson
authors.affiliation: Department of Chemistry, Umeå University , 90187 Umeå, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Fick
mesh_terms: D014151:Anti-Anxiety Agents / Q000032:analysis*; D005843:Geography; D019015:Geologic Sediments / Q000737:chemistry; D006801:Humans; D060106:Lakes / Q000737:chemistry*; D010076:Oxazepam / Q000032:analysis*; D045483:Rivers / Q000737:chemistry; D013548:Sweden; D013997:Time Factors; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D014151:Anti-Anxiety Agents; D014874:Water Pollutants, Chemical; D014867:Water; D010076:Oxazepam