Temporal and spatial variation in pharmaceutical concentrations in an urban river system

Abstract

Many studies have quantified pharmaceuticals in the environment, few however, have incorporated detailed temporal and spatial variability due to associated costs in terms of time and materials. Here, we target 33 physico-chemically diverse pharmaceuticals in a spatiotemporal exposure study into the occurrence of pharmaceuticals in the wastewater system and the Rivers Ouse and Foss (two diverse river systems) in the city of York, UK. Removal rates in two of the WWTPs sampled (a conventional activated sludge (CAS) and trickling filter plant) ranged from not eliminated (carbamazepine) to >99% (paracetamol). Data comparisons indicate that pharmaceutical exposures in river systems are highly variable regionally, in part due to variability in prescribing practices, hydrology, wastewater management, and urbanisation and that select annual median pharmaceutical concentrations observed in this study were higher than those previously observed in the European Union and Asia thus far. Significant spatial variability was found between all sites in both river systems, while seasonal variability was significant for 86% and 50% of compounds in the River Foss and Ouse, respectively. Seasonal variations in flow, in-stream attenuation, usage and septic effluent releases are suspected drivers behind some of the observed temporal exposure variability. When the data were used to evaluate a simple environmental exposure model for pharmaceuticals, mean ratios of predicted environmental concentrations (PECs), obtained using the model, to measured environmental concentrations (MECs) were 0.51 and 0.04 for the River Foss and River Ouse, respectively. Such PEC/MEC ratios indicate that the model underestimates actual concentrations in both river systems, but to a much greater extent in the larger River Ouse.

Acetaminophen adsorption using a low‐cost adsorbent prepared from modified residues of Moringa oleifera Lam. seed husks

“…As a complement, Burns et al . and Paíga et al . observed that in influents of wastewater treatment plants, the contaminant in question obtained the most significant concentrations, resulting in higher effluent loads after inefficient treatment.…”

“…Conventional treatment of water and wastewater is often unable to remove pharmaceuticals completely, including acetaminophen, which is discharged continuously in aqueous environments . Therefore, it is necessary to investigate complementary methods to effectively remove such pharmaceutical pollutants from water.…”

“…6 Quesada et al 7 stated that in surface waters there are traces of acetaminophen in concentrations ranging from 0.03 to 9822 ng L −1 , the highest concentration of 18 common pharmaceuticals surveyed. As a complement, Burns et al and Paíga et al 8,9 observed that in influents of wastewater treatment plants, the contaminant in question obtained the most significant concentrations, resulting in higher effluent loads after inefficient treatment.…”

“…Conventional treatment of water and wastewater is often unable to remove pharmaceuticals completely, including acetaminophen, which is discharged continuously in aqueous environments. [8][9][10] Therefore, it is necessary to investigate complementary methods to effectively remove such pharmaceutical pollutants from water. Adsorption is considered an efficient technology for the removal of organic and inorganic compounds from water due to its low cost, easy operation and production of high-quality treated effluents without the generation of dangerous products.…”

Application of prioritization approaches to optimize environmental monitoring and testing of pharmaceuticals

“…Further, spatial and temporal variations in pharmaceutical usage and environmental conditions might impact the accuracy of exposure predictions. (Burns et al 2018). Currently, there are no apparent models or initiatives to include this temporal variability in exposure predictions, which is a limitation of both prioritization and risk assessment initiatives.…”