Triclosan Concentrations and Antibiotic Sensitivity at Wastewater Treatment Plant Outfalls in Outlet Creek, Iowa

by Rhonda Wemark
Environmental Science
Faculty advisor: Dr. Melinda Coogan

Triclosan is a down-the-drain chemical found in many household products ranging from hand soaps to toothpaste. As an antimicrobial generalist, triclosan affects lipid synthesis in bacterial membranes. This research investigated triclosan concentrations on 10/12/2009 at the Outlet Creek, IA outfalls of Storm Lake, IA Wastewater Treatment Plant (WWTP) facility and Tyson Foods, Inc. WWTP. Additionally, bacterial identification and antibiotic resistance studies were conducted on collected samples. An enzyme-linked immunosorbent assay (ELISA) method was used to quantify triclosan concentrations. Bacterial identification was accomplished by using Enterotubes. Triclosan concentrations in Outlet Creek were found to be between 0.04 and 0.08 ppb.  Bacteria identified from the sample sites were of the Enterobacter genus. Sensitivity results indicated bacterial resistance to triclosan at 1000, 100, 10.0, 1.0, 0.1, and 0.01 ppb. Among the eight antibiotics tested, greater resistance to amoxicillin, polymyxcin B, and vancomycin was observed.