Occurrence of Antimicrobials in the Final Effluents of Wastewater Treatment Plants in Canada

Abstract

To investigate the occurrence of antimicrobials in the final effluents from wastewater treatment plants (WWTPs) in Canada, analytical methods were developed or modified from previously described methods using solid-phase extraction followed by liquid chromatography-electrospray ionization tandem mass spectrometry. Thirty-one antimicrobials from the macrolide, quinolone, quinoxaline dioxide, sulfonamide, and tetracycline classes were investigated in the final (treated) effluents from eight WWTPs, located in five Canadian cities. Ciprofloxacin, clarithromycin, erythromycin-H20, ofloxacin, sulfamethoxazole, sulfapyridine, and tetracycline were frequently detected in the effluents. The detection of sulfapyridine in effluents is the first report of this compound in environmental samples. Antimicrobials used exclusively for veterinary applications or treatment of livestock, such as carbadox, olaquindox, and chlortetracycline were not detected in the WWTP final effluents. There appear to be differences in the relative concentrations of antimicrobials detected in WWTP final effluents in Canada relative to concentrations reported previously in northern Europe, particularly for quinolone and sulfonamide compounds. These data may reflect differences in prescription patterns in Canada and northern Europe. The antimicrobials frequently detected in WWTP effluents appear to be those prescribed heavily in Canada for medical applications, and these compounds should be considered priority compounds for monitoring in surface water near WWTP discharges. The concentrations of antimicrobials detected in WWTP final effluents did not exceed 1 microg/L; levels that are unlikely to affect the growth and survival of aquatic organisms.

Occurrence and fate of eleven classes of antibiotics in two typical wastewater treatment plants in South China

“…For the macrolides, anhydro erythromycin was detected at higher concentrations in the wastewater than clarithromycin and roxithromycin, which is consistent with those in other regions of China (Peng et al, 2011;Xu et al, 2007) and Canada (Miao et al, 2004) but different to those in Switzerland (Gobel et al, 2007). This regional difference in their concentrations in wastewater is a reflection of variable prescription and consumption patterns (Miao et al, 2004).…”

“…This regional difference in their concentrations in wastewater is a reflection of variable prescription and consumption patterns (Miao et al, 2004).…”

An overview of analytical methodologies for the determination of antibiotics in environmental waters

“…In majority of methods the sample pH was adjusted to acidic values in order to obtain required chemical form of analytes. In some cases, pH was adjusted to high values, especially when MLs were included [22,23,[25][26][27].…”

“…In majority of multiresidue studies, the sample pH was adjusted in pH range 2.5-4 by sulphuric or hydrochloric acid. Some authors used sample of pH 6.0 or higher usually when MLs were included in the study together with other antibiotics or pharmaceuticals [22][23][24][25][26][27]. In some studies the best SPE recoveries were reported with no sample pH adjustment [28].…”

“…To obtain sufficient recovery from the environmental matrices some chelator should be added [30,31]. Chelating agents such as EDTA, oxalic acid and citric acid are usually applied to decrease the tendency for antibiotics to bind to cations in the matrix, to improve peak shape and to prevent interferences during the extraction of antibiotics [22]. The addition of strong chelator EDTA to the sample prior to extraction is mostly utilized to chelate metals or multivalent cations (residual metal ions) that are sufficiently soluble in water.…”