Carbamazepine and Its Metabolites in Wastewater and in Biosolids in a Municipal Wastewater Treatment Plant

• Published in: Environmental science & technology Vol. 39; no. 19; pp. 7469 - 7475
• Main Authors: Miao, Xiu-Sheng, Yang, Jian-Jun, Metcalfe, Chris D
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.10.2005
• Subjects: Applied sciences; Biological and medical sciences; Biological treatment of waters; Biotechnology; Caffeine; Caffeine - analysis; Carbamazepine - analysis; Carbamazepine - chemistry; Chromatography, Liquid; Effluents; Environment and pollution; Environmental Monitoring - statistics & numerical data; Environmental science; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Industrial applications and implications. Economical aspects; Ions; Metabolites; Ontario; Other industrial wastes. Sewage sludge; Other wastewaters; Pollution; Prescription drugs; Sewage - chemistry; Sludge; Spectrometry, Mass, Electrospray Ionization; Waste Disposal, Fluid; Wastes; Wastewaters; Water Pollutants, Chemical - analysis; Water treatment; Water treatment and pollution; Water treatment plants; Ontario; Drug; Chemical analysis; Metabolite; Anticonvulsant; Liquid chromatography; Marker; Sewage sludge; Carbamazepine; Electrospray; Sewage treatment plant; Biological purification; Domestic waste water; Mass spectrometry MS/MS; Urban waste water; Physicochemical purification; Waste water purification; Waste water discharge; Degradation product; Material balance; Dibenzazepine derivatives; Organic compounds; Quantitative analysis; Caffeine
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es050261e

Pharmaceutically active compounds (PhACs) are discharged into the environment from domestic wastewater treatment plants (WWTPs). In this study, we determined the distribution of the anti-epileptic drug, carbamazepine (CBZ), and its major metabolites and caffeine in both aqueous and solid phases through different treatment processes of a WWTP. A method was developed to extract samples of biosolids using pressurized liquid extraction (PLE), coupled with cleanup of extracts using solid-phase extraction. Samples of biosolids and wastewater were analyzed for caffeine and CBZ and five of its metabolites, 10,11-dihydro-10,11-epoxycarbamazepine (CBZ-EP), 11-dihydro-10,11-epoxycarbamazepine (CBZ-DiOH), 2-hydroxycarbamazepine (CBZ-2OH), 3-hydroxycarbamazepine (CBZ-3OH), and 10,11-dihydro-10-hydroxycarbamazepine (CBZ-10OH). The analytes were quantified using liquid chromatography−electrospray ionization tandem mass spectrometry. The recoveries of the analytes were 82.1−91.3% from raw biosolids and 80.1−92.4% from treated biosolids, and the limits of detection were 0.06−0.50 and 0.06−0.40 μg/kg on a wet weight basis for raw and treated biosolids, respectively. The behavior of carbamazepine and its metabolites, together with caffeine as a marker of domestic inputs, was investigated in the WWTP for the City of Peterborough, ON, Canada, which utilizes secondary sewage treatment technologies. CBZ, CBZ-2OH, CBZ-3OH, and CBZ-DiOH were detected at concentrations of 69.6, 1.9, 1.6, and 7.5 μg/kg (dry weight), respectively, in untreated biosolids and at concentrations of 258.1, 3.4, 4.3, and 15.4 μg/kg (dry weight), respectively, in treated biosolids. However, CBZ-EP and CBZ-10OH were not detected in any of the biosolid samples. CBZ and its five metabolites were detected in all wastewater samples collected from four different stages of treatment. The results showed that 29% of the carbamazepine was removed from the aqueous phase during treatment in the WWTP, while the metabolites were not effectively removed. Concentrations of caffeine were reduced by 99.9% in the aqueous phase, which appeared to be due primarily to degradation. Caffeine was also detected at concentrations of 165.8 and 7.6 μg/kg (dry weight) in raw and treated biosolids, respectively. Because of differences in hydrophobicity, CBZ is the primary analyte in biosolids, while CBZ-DiOH is the primary analyte in the aqueous phase of the wastewater. A mass balance calculation showed that the majority of CBZ and its metabolites exist in the aqueous phase (i.e., wastewater), rather than in the biosolids, 78 g of CBZ and its metabolites enters the Peterborough WWTP daily, and 91 g is discharged from the WWTP daily in the combined suspended solids and aqueous phases of the wastewater. The calculated daily inputs into the WWTP are somewhat less than the inputs of 192 g estimated from Canadian annual sales data for CBZ.