Influence of hydrologic and anthropogenic drivers on emerging organic contaminants (EOCs) in drinking water sources in the Susquehanna River Basin

Authors: KIBUYE, FAITH - Pennsylvania State University; GALL, HEATHER - Pennsylvania State University; Veith, Tameria - Tamie; Elkin, Kyle; ELLIOTT, HERSCHEL - Pennsylvania State University; HARPER, JEREMY - Pennsylvania State University; WATSON, JOHN - Pennsylvania State University

Submitted to: Environmental Pollution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/7/2019
Publication Date: 12/13/2019
Citation: Kibuye, F.A., Gall, H.E., Veith, T.L., Elkin, K.R., Elliott, H.A., Harper, J.P., Watson, J.E. 2019. Influence of hydrologic and anthropogenic drivers on emerging organic contaminants (EOCs) in drinking water sources in the Susquehanna River Basin. Environmental Pollution. 245:125583. https://doi.org/10.1016/j.chemosphere.2019.125583.
DOI: https://doi.org/10.1016/j.chemosphere.2019.125583

Interpretive Summary: The widespread occurrence of emerging organic contaminants (EOCs) in aquatic environments is of concern due to known ecotoxicological and potential human health impacts. Given the temporal variability in EOC concentration and the associated impacts on water quality, understanding the dominant factors that influence the temporal variability of EOCs in surface water sources is essential. In this study, we evaluated the spatial and temporal variability of 20 EOCs in six riverine and reservoir drinking water sources in the Susquehanna River Basin. Sampling techniques enabled the characterization of the influence of wastewater effluent and variable flow conditions. Detection of EOCs was inversely correlated percentage of forested land use for each study site. EOCs depicted varying hydrologic transport characteristics. Human pharmaceuticals known to persist in wastewater effluent were present at lower concentrations during high flow conditions, consistent with diminished wastewater signals during surface runoff events. However, a neonicotinoid insecticide exhibited higher concentrations during higher flow rates, suggesting overland flow from agricultural land uses as the dominant transport pathway. Risk calculations revealed that EOCs posed medium to high risk to aquatic organisms; however, human health risk via fish consumption from impacted surface water sources was low.

Technical Abstract: Occurrence of emerging organic contaminants (EOCs) in surface water bodies can cause adverse effects on non-target organisms. When surface water is used as a drinking water source, temporal variability in EOC concentrations has the potential to impact drinking water quality and human health. To better understand spatiotemporal variability of EOCs in drinking water sources in Central Pennsylvania, EOCs were evaluated in six drinking water sources during a two-year study period (April 2016 – June 2018) in the Susquehanna River Basin (SRB). The study was conducted in two phases: Phase I was a spatially distributed sampling approach within the SRB focusing on seven human pharmaceuticals, and Phase II was a temporally intensive sampling regime at a single site focusing on a broader range of EOCs. Concentration-discharge relationships were utilized to classify EOC transport dynamics and understand the extent to which hydrologic and anthropogenic factors, such as surface runoff and wastewater effluent, may contribute to EOC occurrence. Overall, EOCs were present at higher concentrations in colder seasons than warmer seasons. Thiamethoxam, a neonicotinoid insecticide, and caffeine exhibited accretion dynamics during high-flow periods, suggesting higher transport during surface runoff events. Human pharmaceuticals known to persist in wastewater effluent were inversely correlated with discharge, indicating dilution characteristics consistent with diminished wastewater signals during surface runoff events. Acetaminophen exhibited episodic transport dynamics indicating nonpoint source inputs during high-flow periods. Risk calculations revealed that although EOCs posed medium to high risk to fish and other aquatic organisms, human health risk through fish consumption was low.