The distribution dynamics and desorption behaviour of mobile pharmaceuticals and caffeine to combined sewer sediments. (1st January 2017)

• Record Type: Journal Article
• Authors: Hajj-Mohamad, M.; Darwano, H.; Duy, S. Vo; Sauvé, S.; Prévost, M.; Arp, H.P.H.; Dorner, S.
• Is Part Of: Water research. Volume 108(2017)
• Page Start: 57
• Page End: 67
• Publication Date: 2017-01-01
• Subjects: Emerging contaminants -- Anthropogenic tracers -- Suspended solids -- Settled sediment -- Stormwater -- Batch equilibrium; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2016.10.053
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: Pharmaceuticals are discharged to the environment from wastewater resource recovery facilities, sewer overflows, and illicit sewer connections. To understand the fate of pharmaceuticals, there is a need to better understand their sorption dynamics to suspended sediments (SS) and settled sediments (StS) in sewer systems. In this study, such sorption dynamics to both SS and StS were assessed using a batch equilibrium method under both static and dynamic conditions. Experiments were performed with natively occurring and artificially modified concentrations of sewer pharmaceuticals (acetaminophen, theophylline, carbamazepine, and a metabolite of carbamazepine) and caffeine. Differences in apparent distribution coefficients, Kd, app, between SS and StS were related to differences in their organic carbon (OC) content, and the practice of artificially modifying the concentration. Kd, app values of modified contaminant concentrations and high OC sediments were substantially higher. Pseudo-second order desorption rates for these mobile compounds were also quantified. Successive flushing events to simulate the addition of stormwater to sewer networks revealed that aqueous concentrations would not necessarily decrease, because the added water will rapidly return to equilibrium concentrations with the sediments. Sorption and desorption kinetics must be considered in addition to dilution, to avoid underestimating the influence of dilution on concentrations of pharmaceuticals discharged to the environment. Graphical abstract: Highlights: Kd, app values were greater in non-native sediments than in native sediments. The initial dilution had the greatest influence on pharmaceutical desorption. Monitoring programs are missing particulate pharmaceutical concentrations and dynamics. ACE, CBZ, and CBZ-DiOH are good dynamic tracers of stormwater in combined sewers.