Ketamine and the metabolite norketamine: Persistence and phototransformation toxicity in hospital wastewater and surface water
Journal
Water Research
Journal Volume
53
Pages
351-360
Date Issued
2014
Author(s)
Abstract
Ketamine has been increasingly used both recreationally and medicinally around the world. Although the metabolic pathways to form its metabolite norketamine have been carefully investigated in humans and animals, knowledge of their environmental occurrence and fate is limited. In this study, we investigated the occurrence of ketamine and norketamine in 20 natural bodies of water, effluents from 13 hospitals, two wastewater treatment plants and one water supply plant. Ketamine was found at concentrations as high as 10μg/L. Ketamine and norketamine were consistently found in similar concentrations (ketamine/norketamine ratio: 0.3-4.6) in the collected water samples, and this ratio similar to that found in urine samples. Dark incubation experiments have shown that ketamine is not susceptible to microbial degradation or hydrolysis. Phototransformation was demonstrated to significantly reduce the concentration of ketamine and norketamine in river waters (t1/2=12.6±0.4 and 10.1±0.4h, respectively) and resulted in byproducts that are similar to human metabolites. Both direct and indirect photolysis led to the N-demethylation of ketamine to form norketamine and other byproducts, including hydroxy-norketamine (HNK), dehydronorketamine (DNK), hydroxy-ketamine (HK) and isomer forms of ketamine and norketamine. Irradiated solutions exhibited higher toxicity (via the Microtox? test). Although a final risk assessment could not be made due to a lack of studies on the chronic effects on aquatic organisms, the high and persistent environmental occurrences of ketamine and norketamine as well as the increasingly acute toxicity of the photo byproducts demonstrate the importance of including metabolites in evaluation of the overall risk of ketamine. ? 2014 Elsevier Ltd.
Subjects
Ketamine; Norketamine; Occurrence; Sunlight photolysis; Toxicity
SDGs
Other Subjects
Aquatic organisms; Biodegradation; Biomolecules; Effluents; Hospitals; Metabolites; Petroleum reservoir evaluation; Photolysis; Risk assessment; Surface waters; Toxicity; Wastewater treatment; Water supply; Water treatment; Direct and indirect photolysis; Environmental occurrence; Ketamine; Microbial degradation; Norketamine; Occurrence; Phototransformations; Wastewater treatment plants; Amines; drug metabolite; ketamine; river water; surface water; concentration (composition); environmental risk; irradiance; light effect; metabolite; persistence; surface water; toxicity; wastewater; acute toxicity; aquatic species; article; controlled study; effluent; health hazard; hospital; hydrolysis; isomer; liquid chromatography; microbial degradation; photodegradation; photolysis; priority journal; risk assessment; solid phase extraction; tandem mass spectrometry; urinalysis; waste water; waste water management; water supply; Ketamine; Norketamine; Occurrence; Sunlight photolysis; Toxicity; Aliivibrio fischeri; Chromatography, Liquid; Environmental Monitoring; Fresh Water; Hospitals; Ketamine; Lethal Dose 50; Photolysis; Taiwan; Tandem Mass Spectrometry; Waste Water; Water Pollutants, Chemical
Type
journal article