Larry B. Barber Joseph W. Duris William T. Foreman Edward T. Furlong Laura E. Hubbard Kasey J. Hutchinson Steffanie H. Keefe Dana W. Kolpin Paul M. Bradley 2014 Pharmaceutical contamination of shallow groundwater is a substantial concern in effluent-dominated streams, due to high aqueous mobility, designed bioactivity, and effluent-driven hydraulic gradients. In October and December 2012, effluent contributed approximately 99% and 71%, respectively, to downstream flow in Fourmile Creek, Iowa, USA. Strong hydrologic connectivity was observed between surface-water and shallow-groundwater. Carbamazepine, sulfamethoxazole, and immunologically-related compounds were detected in groundwater at greater than 0.02 μg L⁻¹ at distances up to 6 m from the stream bank. Direct aqueous-injection HPLC-MS/MS revealed 43% and 55% of 110 total pharmaceutical analytes in surface-water samples in October and December, respectively, with 16% and 6%, respectively, detected in groundwater approximately 20 m from the stream bank. The results demonstrate the importance of effluent discharge as a driver of local hydrologic conditions in an effluent-impacted stream and thus as a fundamental control on surface-water to groundwater transport of effluent-derived pharmaceutical contaminants. application/pdf 10.1016/j.envpol.2014.06.028 en Elsevier Riverbank filtration potential of pharmaceuticals in a wastewater-impacted stream article