These particular PPCPs were selected
for inclusion in this study based on previous occurrence data,
usage, and suspected toxicity (Yu, 2007). Stock solutions of the
mixture of aqueous PPCPs were prepared with 100 mg/L for
each compound. One column served as an abiotic control by
receiving mercuric chloride as a bacteriostatic agent, while
another served as a background control by not receiving any
PPCPs in its medium. Each column’s feed solution was
prepared in a 1 L volume and was replenished approximately
every six days. Media were filter-sterilized using Supor
hydrophilic polyethersulfone membranes (0.2 mm pore size,
Pall Life Sciences, Port Washington, NY). Pump settings were
adjusted as needed to maintain flow rates of approximately
0.1 mL/min.