Distribution of antidepressant residues in wastewater and biosolids following different treatment processes by municipal wastewater treatment plants in Canada.
The fate of 14 antidepressants along with their respective N-desmethyl metabolites and the anticonvulsive drug carbamazepine (CBZ) was studied in 5 different sewage treatment plants (STPs) across Canada. Using two validated LC-MS/MS analytical methods, the concentrations of the different compounds were determined in raw influent, final effluent and treated biosolids samples. Out of the 15 compounds investigated, 13 were positively detected in most 24-h composite raw influent samples. Analysis showed that venlafaxine (VEN), its metabolite O-desmethylvenlafaxine (DVEN), citalopram (CIT), and CBZ were detected at the highest concentrations in raw influent (up to 4.3 μg L(-1) for DVEN). Cumulated results showed strong evidence that primary treatment and trickling filter/solids contact has limited capacity to remove antidepressants from sewage, while activated sludge, biological aerated filter, and biological nutrient removal processes yielded moderate results (mean removal rates: 30%). The more recalcitrant compounds to be eliminated from secondary STPs were VEN, DVEN and CBZ with mean removal rates close to 12%. Parent compounds were removed to a greater degree than their metabolites. The highest mean concentrations in treated biosolids samples were found for CIT (1033 ng g(-1)), amitriptyline (768 ng g(-1)), and VEN (833 ng g(-1)). Experimental sorption coefficients (K(d)) were also determined. The lowest K(d) values were obtained with VEN, DVEN, and CBZ (67-490 L kg(-1)). Sorption of these compounds on solids was assumed negligible (log K(d) ≤ 2). However, important sorption on solids was observed for sertraline, desmethylsertraline, paroxetine and fluoxetine (log K(d) > 4).
Environment Canada, Aquatic Contaminants Research Division, Water Science and Technology Directorate, 105 McGill Street, Montreal, Quebec, Canada H2Y 2E7.
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Lajeunesse
Environment Canada, Aquatic Ecosystems Management Research, Science and Technology Branch, 867 Lakeshore Road, Burlington, Ontario, Canada L7R 4A6.
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Smyth
Environment Canada, Aquatic Ecosystems Management Research, Science and Technology Branch, 867 Lakeshore Road, Burlington, Ontario, Canada L7R 4A6.
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Barclay
Université de Montréal, Department of Chemistry, P.O. Box 6128 Downtown, Montreal, Quebec, Canada H3C 3J7.
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Sauvé
Environment Canada, Aquatic Contaminants Research Division, Water Science and Technology Directorate, 105 McGill Street, Montreal, Quebec, Canada H2Y 2E7. Electronic address: christian.gagnon@ec.gc.ca.
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Gagnon
D000928:Antidepressive Agents / Q000302:isolation & purification*; D002170:Canada; D002853:Chromatography, Liquid; D012722:Sewage / Q000737:chemistry; D053719:Tandem Mass Spectrometry; D014865:Waste Disposal, Fluid / Q000379:methods
D000928:Antidepressive Agents; D012722:Sewage