628 (BEN-1117-831465) Pharmaceuticals as tracers of municipal wastewaters in urban estuaries.
Start time: 8:00 AM
Benotti, Mark¹, Brownawell, Bruce¹, ¹ Stony Brook University, Stony Brook, NY, USA
The widespread distribution of many pharmaceuticals in wastewater effluents and receiving waters attests to their relative persistence. Attributes that might make this class of compounds powerful tracers of wastewater influence include their resistance to microbial transformation, lack of natural background signals, typically high water solubilities and low tendencies to be volatilized or removed by suspended particles. Wastewater tracers may be useful to better understand physical mixing of waters as well as trace the sources of other chemical and microbial contaminants in receiving waters. Here, we present data on the distributions of a broad suite of high-volume pharmaceuticals Jamaica Bay, a sewage-impacted estuary in New York City. As municipal wastewater is known to be the primary source of freshwater to the Bay, pharmaceutical concentrations should vary in a linear fashion with salinity if they behave conservatively and effluent concentrations are constant over the timescales on the order of the 2-4 week residence time in the Bay. For several pharmaceuticals, a linear relationship between concentration and salinity was observed, and extrapolations of such relationships were consistent with measured concentrations from one of the major sewage treatment plants that discharges to the Bay. The apparently conservative behavior of selected pharmaceuticals was also consistent with slow transformation observed in die-away studies conducted with water from NY Harbor. With the analytical methods employed, pharmaceutical tracers can be detected at 0.1% of wastewater effluent concentrations with caffeine and paraxanthine being the potential tracers with greatest signals relative to method detection limits. Much lower concentrations of pharmaceuticals could be measured if more selective compound-specific selective methods of extraction and isolation are employed.

629 (ROT-1117-834293) Transport and fate of selected priority pharmaceuticals in the US environment.
Start time: 8:20 AM
Roth, C.¹, Dong, Z.¹, Senn, D.¹, MacLeod, M.², Shine, J.¹, ¹ Harvard University, Boston, MA, USA² Swiss Federal Institute of Technology (ETHZ), Zurich, Switzerland
Pharmaceuticals enter the environment after use or unused after disposal mainly through the wastewater system. As their removal in wastewater treatment plants (WWTP) is often not 100% they pose a risk to the aquatic environment. A range of pharmaceuticals used in the US market has been determined as top-priority compounds based on information such as sales, metabolism, degradation in WWTPs and toxicity. The environmental exposure of a selection of these pharmaceuticals is assessed by a multimedia fate and transport model. With the BETR-North America model, environmental distribution in seven compartments in 24 North American regions is calculated based on refined input parameters. These parameters include degradation in the environment, including estimates of biodegradation, photodegradation and other reactions of the mostly charged species. A range of estimation methods is used to approach speciation and possible degradation processes. Partitioning in various environmental sorbents is estimated with poly-parameter linear free energy relationships (LFER), an approach novel in multimedia modeling. Poly-parameter LFERs are not only based on one parameter such as the octanol-water partitioning coefficient, but include several parameters accounting for the diverse intermolecular interactions taking place in sorption of organic pollutants. Results show the exposure of the aquatic system to these pharmaceuticals, some of which have not yet been examined for their occurrence in and potential risk to the environment.

630 (ERI-1117-809500) Environmental Fate Testing for New Human Pharmaceutical Candidates.
Start time: 8:40 AM
Ericson, J¹, Huggett, D¹, Constantine, L¹, ¹ Pfizer Inc, Pfizer Global R&D, Chemical R&D, Environmental Sciences, Groton, CT, USA
Trace levels of pharmaceuticals detected in wastewater effluents and surface waters have raised the level of attention around the ultimate fate and persistence of pharmaceuticals in the environment. The proposed Environmental Risk Assessment (ERA) guidance also brings a base set of testing to characterize water-sediment biodegradation. While the proposed guidance suggests a need for methods focused on the end environment, it is perhaps best characterized when presented in the context of all available data that describes physical properties, propensity to partition into the various environmental compartments and its susceptibility to microbial biotransformation and mineralization as it is transported through wastewater, surface water and sediment compartments. Therefore, a flexible approach is needed in the environmental testing strategy that enables scientists to fully utilize existing information and emerging technologies to better define testing needs that in the end will enhance the overall ERA process and the characterization as to whether something may or may not persist. Pfizer proposes a tiered testing strategy that leverages: 1) available pre-clinical and physical-chemical data in conjunction with environmental models to assess what environmental compartments are of concern; and 2) existing metabolism and pure culture biotransformation data to assess susceptibility to environmental biotransformation and mineralization. This pretest assessment allows one to identify any potential issues with the selected test methods, assess the extent of analytical testing needed to support the sludge, water and sediment methods, and hopefully anticipate some of the outcomes such that when the definitive tests are run the resulting data will be more meaningful and robust.

(59261) Break.
Start time: 9:20 AM

632 (RAM-1117-547923) Fate of pharmaceuticals in sediments.
Start time: 10:00 AM
Ramil, M.¹, Loeffler, D.¹, Fink, G.¹, Ternes, T. A.¹, ¹ Federal Institute of Hydrology, Koblenz, Germany
During the last few years, the understanding of the fate and effects of pharmaceuticals in the environment has progressed significantly, but there is still much work to do for a complete evaluation of the risks associated to the ubiquitous presence of these compounds. Fate studies carried out recently have been based on factors and processes affecting the behavior of veterinary medicines applied to soils in slurry and manure, or the photodegradation of selected human medicines in surface waters. However, there is a lack of information about further degradation processes in rivers and streams, on fate in estuarine and marine systems and on the extent of sorption to suspended matter and sediments. The fate of selected pharmaceuticals and some of their metabolites has been investigated in aerobic water/sediment tests according to OECD Guideline 308 in order to elucidate their potential accumulation in the aqueous medium. Analysis was carried out either by radio-TLC or LC-tandem MS depending on the availability of C14-standards. The different affinity of studied compounds for the sediment compartment, together with some further data about biodegradation and mineralisation will be discussed.

633 (BEL-1117-810385) Partitioning of ciprofloxacin in aquatic systems.
Start time: 10:20 AM
Belden, J¹, Maul, J¹, Lydy, M¹, ¹ Southern Illinois University, Carbondale, IL, USA
Fluoroquinolone antibiotics are of environmental concern due to wide usage, low degradability by microorganisms, and detection in stream and river water. This class of antibiotics has high water-soil partitioning coefficients, high water solubility, and is highly photodegradable; however, little else is known about the fate of these chemicals in aquatic environments. The objective of this research was to study the partitioning of a model fluoroquinolone, ciprofloxacin, in aquatic systems. Specifically, partitioning of ¹⁴C-ciprofloxacin (cipro) was measured between water and several other matrices that may be present within aquatic systems including sediment, fresh leaf material, degraded leaf material, algae, and particulate matter. Cipro accumulated on each matrix tested with varying magnitudes of accumulation. For example, cipro accumulated on fresh leaf material with concentrations on the leaf 300 times that found in the water while for degraded leaf material, concentrations were nearly 20,000 times the concentration of surrounding water indicating that specific microbial niches may be of greater risk of impact than others. The desorption potential also varied widely between matices. For instance, desorption from sediment was nearly negligible while desorption from leaf material was clearly demonstrated with comparatively little hysteresis. Thus, accumulation in some matrices may serve as a sink allowing little bioavailability, while absorption to other matrices may result in greater potential environmental impact.

634 (ARM-1117-817021) Environmental occurrence and fate of selective serotonin reuptake inhibitors in aquatic environments.
Start time: 10:40 AM
Armbrust, Kevin¹, Kwon, Jeong-Wook¹, ¹ Mississippi State Chemical Laboratory, Mississippi State University, Mississippi State, MS, USA
Pharmaceuticals can enter aquatic environments after their prescribed use and lead to negative effects on aquatic organisms. Of particular concern are drugs that are hormonally active because disruption of physiological processes in aquatic organisms can occur at low environmental concentrations. Selective serotonin reuptake inhibitors (SSRIs) are among the most heavily prescribed drugs, they are hormonally active, low concentrations have been shown to affect aquatic organisms, and evidence indicates that they can be present in effluents from wastewater treatment plants. The present research includes the environmental fate of five SSRIs (citalopram, fluoxetine, fluvoxamine, paroxetine, and sertraline) and the their occurrence in surface waters. Analyses of SSRIs showed high water solubilities and relatively low octanol-water partition coefficients. Sediments and soils were used to measure adsorption coefficients. Values of K_f, K_d, and K_oc ranged from 39 to 18342, from 60 to 42579, and from 2256 to 1053380, respectively. In general, pH is the main factor influencing soil sorption. Paroxetine and fluvoxamine rapidly photodegraded and fluoxetine and citalopram are stable to photolysis at all pH ranges. Several degradation products for each SSRI were detected and identified. All SSRIs treated to irradiated water/sediment systems dissipated rapidly, in part due to photolysis but mostly due to adsorption to sediment. Nearly constant SSRI residues over time indicated that SSRIs resist microbial metabolism in sediments. Methods that employ solid-phase extraction (SPE) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) for the determination of five SSRIs and their metabolites in surface water samples have been developed. Fluoxetine and sertraline were detected in all samples, ranging in concentration from 0.006-0.076 ug/L and 0.007-0.061 ug/L, respectively. Citalopram was also detected in selected samples. Laboratory data indicates that the SSRIs as a general class are resistant to most forms of degradation in environmental systems and would partition to sediment where residues of these compounds would persist.

635 (LAT-1117-501368) Dissolved organic matter and the photochemical fate of pharmaceuticals and personal care products.
Start time: 11:00 AM
Latch, Douglas¹, Arnold, William¹, McNeill, Kristopher¹, ¹ University of Minnesota, Minneapolis, MN, United States
Recent work has demonstrated that photochemical degradation processes are important to the fate of many pharmaceuticals and personal care products (PPCPs) in sunlit natural waters. Dissolved organic matter (DOM) is intimately involved in these processes, acting as both sources and sinks of photochemically produced reactive intermediates (PPRIs). In this work, the role of humic substances in the photochemical degradation of three environmentally relevant PPCPs (ranitidine, cimetidine, and triclosan) was examined. Each of the PPCPs examined were photochemically labile, with various dependencies on DOM. Triclosan was rapidly degraded by a direct photolysis mechanism, with two toxic products, 2,8 dichlorodibenzo-p-dioxin and 2,4-dichlorophenol, formed in low yields. In photolysis experiments with added Suwanee River fulvic acid (SRFA), the DOM acted as a sink, with some of the triclosan coupling to the SRFA. Ranitidine also was degraded primarily by direct photolysis, though the PPRI singlet oxygen (¹O₂) contributed to ca. 10 % of the observed degradation rate. Cimetidine did not undergo direct photolysis, but was rapidly degraded by ¹O₂. Because ¹O₂ is involved in the fate of ranitidine, cimetidine, and other aquatic contaminants, fundamental studies were undertaken to examine the spatial distribution of ¹O₂ in irradiated aqueous DOM solutions. The microheterogeneous distribution of ¹O₂ in these DOM solutions was elucidated using hydrophobic trap-and-trigger chemiluminescent probe molecules in conjunction with the conventional hydrophilic probe furfuryl alcohol (FFA). The hydrophobic probes measured significantly higher [¹O₂] than did FFA, reflecting the relatively high local [¹O₂] within the DOM. A model was developed to calculate the ratio of [¹O₂] in the DOM and bulk aqueous phases for different size DOM particles. The results of these experiments suggest that hydrophobic pollutants that partition into DOM may be degraded more rapidly than would be predicted based on bulk aqueous phase PPRI concentrations.

636 (SCH-1117-818377) Determination of antidepressant pharmaceuticals and their degradates in municipal wastewater.
Start time: 11:20 AM
Schultz, Melissa¹, Kinney, Chad², Phillips, Patrick ³, Furlong, Edward ¹, ¹ U.S. Geological Survey, Denver, CO, USA² Eastern Washington University, Cheney, WA, USA³ U.S. Geological Survey, Troy, NY, USA
Selective serotonin reuptake inhibitors (SSRIs) are widely prescribed antidepressant pharmaceuticals that include fluoxetine (Prozac¹), sertraline (Zoloft¹), and paroxetine (Paxil¹). Despite 20 years of widespread use, few analytical methods exist to detect SSRIs in environmental matrixes, thus little is known about their distribution and fate in the environment. Previous studies found that fish populations residing in a municipal effluent-dominated stream contained concentrations of fluoxetine, sertraline, norfluoxetine, and desmethylsertraline in all muscle, liver, and brain tissues examined, suggesting that wastewater effluent is one of the possible routes for introducing antidepressant pharmaceuticals into aquatic environments. A quantitative method was developed for the analysis of SSRIs and selected degradates in municipal wastewater. This method also was extended and adapted to determine other antidepressant drugs and their degradates that are prescribed when SSRIs are not effective, including bupropion (Wellbutrin¹), venlafaxine (Effexor¹), and duloxetine (Cymbalta¹). Samples were concentrated by using solid-phase extraction, and the extracts were analyzed by a liquid chromatograph coupled to a tandem mass spectrometer by means of an electrospray interface (LC ESI-MS/MS). Quantitation was based on the ratio of the peak area of the analyte to that of the internal standard, sertraline-d₃. Method quantitation limits were approximately 1 ng/L. Preliminary analyses of antidepressant pharmaceuticals and their degradates in New York and Washington state municipal wastewater samples showed individual levels ranging from 1 ng/L to 40 g/L and 1 ng/L to 160 ng/L, respectively. The validated method was applied to a representative set of municipal wastewater samples collected from plants nationwide. ¹Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.