Casey LeBlanc (cjleblanc@ucdavis.edu)

Department of Civil and Environmental Engineering

University of California, Davis

One Shields Avenue

Davis, CA 95616

Thin Layer Chromatography has numerous existing applications. Screening and identifying legal and illicit drugs, separating chemical mixtures, and culturing bacteria have all been accomplished using Thin Layer Chromatography (TLC). Through this research, Thin Layer Chromatography has been shown to also be an effective method for sampling trace compounds in aqueous systems. Compounds which occur in part per trillion concentrations in the environment can be concentrated onto the silica gel of the TLC plate. Subsequently, a solid phase extraction of the TLC plate yields a sample concentrated with the targeted compounds, and the collected solvent is suitable for analysis using High Performance Liquid Chromatography.

As required by the State of California Assembly Bill 411, three bacterial indicators are monitored to evaluate the health and safety of California’s public beaches. However, fecal and total coliform concentrations have little correlation to pathogens measured in water samples. This research, in part, contributes to the fulfillment of the requirements set forth in the Beaches Environment Assessment and Coastal Health Act of 2000. The Act amends the Federal Water Pollution Control Act of 1972 by including the development of "appropriate and effective indicators for improving detection in a timely manner in coastal recreational waters of the presence of pathogens that are harmful to human health." Ideal indicators should be (1) detected only when pollution or pathogens are present, (2) related proportionally to the degree of pollution, (3) applicable to varied environmental conditions, and (4) distinguished from animal fecal contamination. In order to select potential chemical indicators of pathogens, wastewater samples from the Sacramento Regional Wastewater Treatment Plant were analyzed for seven compounds. The steroids, pharmaceuticals, and food related compounds investigated include estrone (E₁), estradiol (E₂), estriol (E₃), 17-α ethynylestradiol (EE₂), butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and caffeine. Raw sewage, secondary effluent from activated sludge, and disinfected wastewater were analyzed for the parent compound of these seven compounds. Metabolites and conjugation products of these compounds were not included in the analyses. Six of the seven compounds were detected in wastewater. The parent compounds’ presence was variable within the wastewater treatment process. Conjugation of the parent compound is known to occur within the body and in sewers. Including these conjugates and metabolites in the analyses would improve the method’s usefulness for determining the presence of human wastes. The detection of steroids after an activated sludge process may be due to E. coli’s capacity to return conjugated steroids back to their original structure.