Digitized by the Internet Archive in 2010 with funding from Lyrasis Members and Sloan Foundation http://www.archive.org/details/detectionoftriclOOwils DETECTION OF TRICLOSAN IN CENTRAL VIRGINIA WASTEWATER AND IDENTIFICATION OF RESISTANT MICROORGANISMS ASeniorHonorsThesis intheDepartmentsofBiology&Chemistry SweetBriarCollege By KimberlyA. Wilson DefendedandApproved inApril 2006 ProfessorDavid R. Orvos(FacultyAdvisor) date ProfessorJohnJ. Beck date Dr. LeoHsu ' date ABSTRACT Triclosan (5-chloro-2(2,4-dichlorophenoxy)phenol) or (Irgasan® DP 300) is an antimicrobial agent typically used in personal care products to prevent microbial growth and ultimately gets dispersed into the environment. Pharmaceuticals and personal-care products (surfactants, antibiotics, and antimicrobial agents), collectively known as PPCPs, are considered emerging contaminants due to their potential toxicological effects in the environment. This study determined the presence oftriclosan in primary influent wastewater at two Central Virginia wastewater treatment plants. Concentrations oftriclosan varied from 0.6 to 116 ug/L using HPLC analysis. The identification oftriclosan-resistant bacteria in the influent were found using BIOLOG biochemical substrate testing. Several identified strains included Serratia rubidaea, Corynebacterium nitrilophilus, Brevibacterium mcbrellneri, and Burkholderiaglumae. INTRODUCTION Xenobiotics in theAquaticEnvironment The detection of xenobiotics in the environment has been given much attention recently. ' Examples ofxenobiotics include pesticides, fertilizers, detergents, plasticizers and pharmaceuticals/ Xenobiotics, synthetic organic compounds, have been detected in surface waters, groundwaters, andsewagetreatmentplanteffluents.1'3'4Detection ofpharmaceuticals in the aquatic environment are of particular concern due to the potential health risks associated with them. Designed for a specific effect, pharmaceuticals are made to evoke a desired response through anabolism, chemical reactions, or other metabolic pathways. They are engineered to penetrate cellular membranes, to be active at micromolar or nanomolar concentrations, and to remain stable at varying pHs. It is this bioactivity and specificity that makesthemefficacious andpotentiallydangerous toorganisms. Pharmaceuticals enter the environment through excretion following therapeutic use, discharge oftreated wastewater, andbydisposal ofunused medications by consumers."Many xenobiotics are released into the environment due to the inabilityofthe wastewatertreatment plants (WWTPs) to remove them.1'5 Pharmaceuticals and other personal-care products (surfactants, antibiotics, and antimicrobial agents), collectively known as PPCPs, are not mandatedunderthe U.S. Clean WaterActforremoval from wastewater.5Triclosan wasfound in wastewater (0.07-14000 /ig/L), in streams (50-2300 ng/L), in seawater (50-150 ng/L) and in sediments (1-35 pig/kg)6 The annual volume of raw sewage entering surface waters is approximately 860 billion gallons.7 Approximately seven percent ofthe total volume ofU.S. wastewaterenters theenvironment untreated. Triclosan: Physical Properties Triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol or Irgasan® DP 300) is an antimicrobial agent typically used in personal care products such as toothpastes, soaps, shampoos, and deodorants.8"11 A chlorinated biphenyl ether, triclosan is lipophilic and relativelystable, despitethephenolic hydroxyl group (Figure 1). OH CI Figure 1. StructureofTriclosan