Use of the Chiral Pharmaceutical Propranolol to Identify Sewage Discharges into Surface Waters

Abstract

The discharge of relatively small volumes of untreated sewage is a source of wastewater-derived contaminants in surface waters that is often ignored because it is difficult to discriminate from wastewater effluent. To identify raw sewage discharges, we analyzed the two enantiomers of the popular chiral pharmaceutical, propranolol, after derivitization to convert the enantiomers to diastereomers. The enantiomeric fraction (the ratio of the concentration of one of its isomers to the total concentration) of propranolol in the influent of five wastewater treatment plants was 0.50 +/- 0.02, while after secondary treatment it was 0.42 or less. In a laboratory study designed to simulate an activated sludge municipal wastewater treatment system, the enantiomeric fraction of propranolol decreased from 0.5 to 0.43 as the compound underwent biotransformation. In a similar system designed to simulate an effluent-dominanted surface water, the enantiomeric fraction of propranolol remained constant as it underwent biotransformation. Analysis of samples from surface waters with known or suspected discharges of untreated sewage contained propranolol with an enantiomeric fraction of approximately 0.50 whereas surface waters with large discharges of wastewater effluent contained propranolol with enantiomeric fractions similar to those observed in wastewater effluent. Measurement of enantiomers of propranolol may be useful in detecting and documenting contaminants related to leaking sewers and combined sewer overflows.

Enantiomeric fraction evaluation of pharmaceuticals in environmental matrices by liquid chromatography-tandem mass spectrometry

“…2). PHO and MET enantiomers were already found in WWTP effluents at quantifiable concentrations [10,[22][23][24]28,29,49]. Both the metabolite NFLX and the beta 2 -agonist SBT were not found in any of the analysed WWTP.…”

“…Some classes of CP, such as proton pump inhibitors [15,16], antifungals [17], Non Steroid Anti-Inflammatory Drugs (NSAID) [18][19][20][21], beta-blockers [10,12,[22][23][24][25][26][27][28][29][30][31] as well as antidepressants and their metabolites [11][12][13][28][29][30][31][32][33][34], have been reported in environmental matrices, concerning its enantiomers. Regarding antidepressants, enantioselective biodegradation of venlafaxine (VNF) was found in a French river, with racemic VNF at the output of the main WWTP discharging into the river and with EF variation along the river stretch [11].…”

Enantiomeric determination of azole antifungals in wastewater and sludge by liquid chromatography–tandem mass spectrometry

“…Clotrimazole-d 5 (achiral), carbamazepine-d 10 (achiral), ketoconazole-d 8 , and miconazole-d 5 (as the nitrate) were obtained from Toronto Research Chemicals (North York, ON, Canada).…”

“…As a result, biological activity can have different effects on the enantiomers, leading to enrichment or depletion of one enantiomer relative to the other, so-called "enantiomeric fractionation" [4,5]. Chirality has thus been used to gain insight into the behavior and fate of enantiomeric contaminants and to identify sources of contamination in the environment [4,[6][7][8]. Enantiomeric compositions of chiral contaminants are also crucial for accurate environmental risk assessment because of the potential enantiospecific toxic effects [9,10].…”

Chiral Biosensors and Immunosensors

“…During successive steps of sewage treatment the amount of R enantiomer in relation to both enantiomers decreased to even less then 40% regardless the concentration of compound. Determination of enantiomeric fraction (the ratio of the concentration of one of the isomers to the total concentration) can be useful indicator to evaluate if examined water is significantly affected by untreated sewage, for example as a result of leaking sewers and to apportion the contribution of treated and untreated sewage into surface waters (Fono & Sedlak, 2005). In a similar manner the source of groundwater contamination in Switzerland by specifying the content of enantiomers of the herbicide Mecoprop was determined.…”