Justin Conley
Justin Conley, Spatial and Temporal Analysis of Pharmaceutical Concentrations and Chitobiase Activity in the Upper Tennessee River
Faculty Chair: Dr. Sean Richards
Thesis Abstract
Tennessee currently has the 3rd highest per capita prescription drug usage rate in the United States, yet no published studies have analyzed Tennessee surface waters for the presence of pharmaceuticals. Composite surface samples were collected upstream and downstream of sewage treatment plants and at the inflow of major tributaries to the Tennessee River to determine the presence and potential sources of pharmaceuticals. Subsurface samples were collected at 7 meters depth to determine differences in occurrence and potential natural degradation. All samples were collected once during each of the four seasons (winter, springs, summer, and fall) to determine yearly variations. Aliquots of each sample were analyzed for pharmaceutical concentrations and chitobiase activity. Chitobiase is an enzyme expressed by developing aquatic invertebrates and may be used as a bioindicator of aquatic invertebrate population health. These two measurements were compared to determine if either total or single pharmaceuticals correlate with chitobiase concentration. The method for the simultaneous quantification of 14 pharmaceuticals in aquatic matrices was developed utilizing solid phase extraction and ultra-performance liquid chromatography (UPLC) interfaced with an electrospray ionization, tandem mass spectrometer (MS/MS). This method yielded reproducible quantitation at the low parts per trillion (ng/L) level for all 14 analytes (acetaminophen, caffeine, carbamazepine, sulfamethoxazole, trimethoprim, ranitidine, ciprofloxacin, levofloxacin, sertraline, fluoxetine, norfluoxetine, diltiazem, lovastatin, and atorvastatin). The simultaneous method pre-concentrated analytes by a factor of 1000 with percent recoveries ranging from 44% to 104% and RSDs below 16%. Percent recoveries were moderately variable due to the broad range of both polarities and acid-base properties.
