WP8 Beyond Occurrence: Fate and Effects of Pharmaceutical and Other Emerging Wastewater Contaminants in Aquatic Systems|
Wednesday, 16 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall
WP090 (AAA-1117-837655) Environmental fate of tylosin and related compounds.
Start time: 8:00 AM
Hu, D1, Henderson, K2, Coats, J3, 1 Pesticide Toxicology Laboratory, Department of Entomology, Ames, IA, USA2 Pesticide Toxicology Laboratory, Department of Entomology, Ames, IA, USA3 Pesticide Toxicology Laboratory, Department of Entomology, Ames, IA, USA
Tylosin is a widely used antibiotic for the treatment of disease and the promotion of growth in swine, beef cattle and poultry production. Tylosin consists of 4 components (A, B, C, D) in its parent formulation. Through the application of organic fertilizers to farmland, tylosin enters into the environment, and its degradation products may form to some extent. The objective of this study was to develop an analytical method suitable for detection of tylosin related compounds, and to investigate their fate in the environment. HPLC conditions for determination of tylosin related compounds were established, and tylosin related compounds were identified by HPLC/MS and purified for further studies. The dissipation of tylosin in pond water and sterilized pond water in the dark and in the light was conducted to evaluate the contribution of biotic degradation compared to the physical/chemical degradation.
WP091 (MIL-1117-837741) Environmental risk assessment of antimicrobial drugs.
Start time: 8:00 AM
Millais, A1, Barrett, K1, 1 Huntingdon Life Sciences, Huntingdon, Cambridgeshire, UK
Antimicrobial drugs may enter the terrestrial environment as a result of veterinary use, and the spreading of manure from treated animals, or as a result of human use, and the spreading of contaminated sewage sludge to agricultural land. The degradation of antibiotics such as -lactams have been evaluated in a laboratory soil degrdation study. In this study it was found that the DT50 was was considerably shorter than expected, in the order of 1 day. The study methods which combined both specific methods of analysis together with a bioassay of microbial activity will be described, and the results presented. Using this experimentally derived infomation the soil Predicted Enviornmental Concentration (PEC)could be revised to reflect the expected pattern of degradation, and the risk assessment refined. The implications for the revised risk assessment will also be presented.
WP092 (SAS-1117-748100) Sorption and degradation of ionophore antibiotics monensin and lasalocid in soils and manure-soil systems.
Start time: 8:00 AM
Sassman, S1, Lee, L1, 1 Purdue University, West Lafayette, IN, USA
Monensin and lasalocid are ionophore antibiotics used for the prevention of coccidiosis in chickens and promotion of growth and milk production in cattle, and enter the environment primarily through land application of animal wastes. These compounds are used at the Purdue University Animal Science Farm where lagoon effluent is applied to the crops through irrigation systems or where manure is injected into the soil. To aid in predicting the mobility and persistence of these compounds in the watershed associated with these farms, we measured sorption by several surface soils, degradation in soils and manure enriched soil systems simulating manure application, and antibiotic concentrations in selected field samples. Sorption was measured from 0.01 N CaCl2 at a soil:solution ratio of 1:30 with initial antibiotic concentrations of 0.01 to 0.25 mg/L and a 48-hour equilibration time. Persistence of the antibiotics was monitored over time in soil microcosms incubated at 23 °C and a 0.03 MPa moisture potential. An initial concentration of 5 mg/kg was chosen to allow for detection of degradation products and tracking of analyte degradation to less than one percent of the applied concentration. Aqueous equilibrium concentrations and acetonitrile extracts of the soils in the sorption and degradation studies were quantified by LC/ESI/MS3 analysis. Sorption of Monensin is approximately linear with a coefficient of 5 to 50 L/kg depending on soil type. Preliminary degradation studies indicate that persistence of Monensin is limited with an estimated pseudo first-order degradation rate of 0.27 day-1 (half-life of less than 3 days); however, Monensin was detected in lagoon effluent samples. Additional experiments outlined for Monensin and lasalocid are currently underway and will be presented.
WP093 (KHA-1117-840669) Sorption and degradation of trenbolone in soils.
Start time: 8:00 AM
Khan, B1, Lee, L1, Sassman, S2, 1 Department Of Agronomy, Purdue University, West Lafayette, IN, USA2 Department Of Agronomy, Purdue University, West Lafayette, IN, USA
The ultimate fate of many excreted anabolic agents is unknown; however measurable amounts of hormones are released from farm animals and reach the environment. Trenbolone (17Beta-hydroxy-4, 9, 11-trien-3-one) is a synthetic androgenic steroid hormone currently used as a growth promoter for farm animals in several meat exporting countries. Trenbolone is administered in its acetate form (TBA) through a subcutaneous implant and hydrolyzed in the body to the trenbolone, which is the active hormone and potent anabolic agent with androgenic, gestagenic and anti-glucocorticoid effects. To aid in predicting the mobility and persistence of trenbolone in the environment, sorption and aerobic degradation studies were conducted with four soils representing a range of organic carbon (OC) content, pH, and % clay. Multiple concentration sorption isotherms were reasonably fit with a linear sorption model. The average OC-normalized sorption coefficient (Koc, L/kg) is 103.3, which is similar to what was previously observed for the natural androgen testosterone. As trenbolone is degraded, it appeared to rapidly re-distribute between the soil and aqueous phases such that sorption equilibrium was nearly maintained. Based on the consistency of Koc values among different soils, organic carbon appears to be the primary domain of sorption. Based on the Koc values and typical OC contents of agricultural chemicals, a large mass fraction of trenbolone and related metabolites will be associated with soil or manure solids. Trenbolone degraded to trendione under aerobic conditions with half lives of less than one week across soils also similar to testosterone. Therefore, although trenbolone has been reported to much longer half-live in anaerobic manure systems (7 to 8 months), once applied to an aerobic soil environment, it is likely to degrade rapidly.
WP094 (CES-1118-173442) Persistence of the antibiotic lincomycin in a prairie wetland.
Start time: 8:00 AM
Cessna, A1, 2, Waiser, M2, Donald, D3, Headley, J2, Bailey, J2, 1 Agriculture and Agri-Food Canada, Saskatoon, SK, Canada2 National Water Research Institute, Saskatoon, SK, Canada3 Environment Canada, Regina, SK, Canada
Lincomycin is an antibiotic used in veterinary medicine to control gastrointestinal infections in swine. Since a portion of the administered dose may be excreted in the faeces and urine, the management practice of applying liquid swine manure to crop and pasture land as a plant nutrient source may result in its transport via surface runoff (rainfall, snow melt) into surface receiving waters. However, little is known about the persistence of lincomycin and other veterinary antibiotics in aquatic ecosystems such as prairie wetlands. A wetland, situated near Saskatoon, Saskatchewan, Canada was fortified with lincomycin at an environmentally relevant concentration (1.5 g L-1) on 20 September 2004. The wetland had a maximum water depth of 0.78 m and a water volume of approximately 622 m3. The water in the wetland was pH = 8 and the dissolved organic carbon concentration was 29.4 mg L-1. Water samples were collected on 19 September and, after fortification, from 21 September until ice formation in October. After ice formation, a water sample was collected through the ice on 3 December and, on 18 January 2005, a sample consisting only of ice was collected because the wetland had frozen to the bottom. Following ice melt in the spring of 2005, water samples will be collected monthly until lincomycin concentrations decrease to less than the limit of quantification (10 ng L-1) of the analytical method. Lincomycin concentrations in the water column > 0.1 g L-1 were monitored by direct injection of the water samples into the LC-MS-MS system. Water samples with lincomycin concentrations < 0.1 g L-1were analyzed by solid-phase extraction followed by LC-MS-MS quantification. The persistence of lincomycin in the wetland is expressed as its half-life in the water column
WP095 (KUC-1117-837010) Analysis of lincomycin and spectinomycin in ground water and surface runoff from manure treated fields.
Start time: 8:00 AM
Kuchta, S1, 2, Peru, K1, Headley, J1, Cessna, A1, 1 National Water Research Institute, Saskatoon, Saskatchewan, Canada2 University of Saskatchewan, Saskatoon, Saskatchewan, Canada
Antibiotics administered to livestock can be excreted up to 80% in the feces and urine. Liquid manure, when applied to cropland as a nutrient source, is thus a possible source of antibiotics to nearby surface and ground waters through runoff and leaching, respectively. The environmental fate of these pharmaceuticals is of increasing concern to the Canadian public. Trace concentrations of veterinary antibiotics have been detected in surface and ground waters in the United States and Europe. In Saskatchewan, Canada, lincomycin and spectinomycin are two antibiotics that are administered together to pigs for the prevention and control of post weaning diarrhea. An analytical method was developed to analyse simulated rainfall runoff, snow melt runoff and ground water samples collected from manure treated cropland for traces of these antibiotics. The method, which uses LC-MS-MS for quantitation and confirmation, allows for concurrent analysis of both lincomycin and spectinomycin with limits of detection being 0.008 and 0.4 ug/L, respectively. Lincomycin was detected in simulated rainfall runoff samples with concentrations ranging from 0.027 to 3.83 ug/L. Concentrations of lincomycin detected in snow melt runoff following fall manure application were 0.024 to 21.7 ug/L. Lincomycin was also detected in ground water samples at trace levels (<100 ng/L). Spectinomycin was not detected in any samples, this may be due to lower sensitivity or due to lower concentrations in the applied manure. Details of the analytical methodology and the concentrations of antibiotic residues detected will be presented and discussed.
WP096 (BIS-1117-835311) The utility of "back-of-the-envelope" approaches in prioritizing environmental occurrence and risk studies on pharmaceuticals.
Start time: 8:00 AM
Bisceglia, K1, Roberts, A1, 1 Department of Geography and Environmental Engineering, Johns Hopkins University, Baltimore, Maryland, U.S.A.
The sheer magnitude of the number of pharmaceuticals of potential environmental concern has forced environmental chemists and engineers to increasingly rely on "back-of-the-envelope" approaches in prioritizing constituents for investigations of environmental occurrence and risk. These approaches, which have also been adopted by government agencies such as the USFDA and the EMEA, typically rely on usage data and publicly available computational toxicology software to identify compounds that are likely to be present at environmentally and ecotoxicologically relevant concentrations. Recent experimental data pertaining to the occurrence, and to a lesser degree, the toxicity of pharmaceuticals in aquatic environments allows us to retrospectively test the utility of preliminary environmental risk assessments based on usage and computationally derived toxicity estimates. To this end, usage data were compiled on the top 200 drugs from the years 1999-2002 in the following categories: brand name, generic, hospital and over-the-counter (OTC). These data were used to compute "expected introductory concentrations" (EICs) according to USFDA guidelines for conducting environmental assessments on human drugs and biologics. Computed EIC values generally fell within an order of magnitude of maximum environmental concentrations (MECs) measured in US wastewaters, but tended to be higher than MECs determined in surface and ground waters. EC50s for the top 200 drugs in each category were computed using the USEPA's ECOSAR software, and were compared to experimentally derived values for similar toxic endpoints. Computed values underpredicted experimental EC50s for most compounds, but were generally within order-of-magnitude agreement. The results from this study indicate that simplistic, "back-of-the-envelope" approaches to investigating occurrence and risk can indeed be effective in prioritizing environmental investigations. We note that more detailed fate and toxicology studies are still required if environmental impact is to be fully characterized.
WP097 (ROB-1117-717714) Detection and degradation potential of phenolic estrogenic compounds in marine samples from Halifax Harbour.
Start time: 8:00 AM
Robinson, B1, Hellou, J1, 2, 1 Department of Oceanography, Dalhousie University, Halifax, Nova Scotia, Canada2 Department of Fisheries and Oceans, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada
There is growing concern over the occurrence of natural and synthetic estrogens in waterways, since low concentrations of endocrine-disrupting compounds (EDC) have been linked to reproductive and developmental effects in aquatic organisms. The occurrence and especially partitioning of EDC has received less attention in marine relative to freshwater environments. With the ongoing construction of sewage treatment plants, Halifax Harbour, Nova Scotia, Canada, presents a unique opportunity to gather baseline data on chemicals discharged in sewage effluents. The phenolic targets 17-estradiol (E2), ethynylestradiol (EE2) and bisphenol-A (BPA) were extracted from seawater using solid phase extraction and from sediment using a sonic probe. Extracts were fractionated to help remove less and more polar anthropogenic chemicals, prior to the identification and quantification of E2, EE2 and BPA. Preliminary analysis of samples yielded concentrations in the low ng/L or ng/g for the three EDC. The partitioning and biodegradation of these compounds spiked individually or concomitantly, in harbour seawater/sediment mixtures was examined for various locations, where concentrations in the aqueous and sediment phases were monitored for up to 28 days, in fresh and autoclaved samples. The following ranking of biodegradation rates E2 > BPA > EE2 was consistently observed, but varied in magnitude with time and location, indicating variability in consortia of micro-organisms or factors influencing the adaptation of micro-organisms capable of degrading these compounds. In general, more partitioning took place onto sediments with higher compared to lower organic carbon content, while bacterial counts in field water was not strictly related to partitioning or degradation rates. Advantages and disadvantages of high performance liquid chromatography (HPLC) with fluorescence detection, gas chromatography/mass spectrometry (GC/MS) and LC/MS/MS analyses, each differently sensitive toward the targets and potential interferences will be discussed relative to matrix effects.
WP098 (KLE-1117-827542) Exposure Analysis of Alkylphenol, Alkylphenol Ethoxylates and Their Metabolites in U.S. Surface Waters.
Start time: 8:00 AM
Zabik, J1, Klecka, G1, Woodburn, K1, Naylor, C2, Staples, C3, 1 The Dow Chemical Company, Midland, MI, USA2 Huntsman Corporation (retired), Austin, TX, USA3 Assessment Technologies Inc, Spotsylvania, VA, USA
Over the past 17 years numerous investigations have examined the levels of alkylphenol ethoxylates (APEO) and their metabolites (APEM) in U.S. surface waters. The available literature was critically reviewed and used to develop a database of environmental monitoring data. A statistical analysis of the available monitoring data suggested that while maximum reported concentrations appear to increase with time, the average environmental concentrations have remained relatively constant. In addition, despite widespread use, APEO/APEM are typically detected in less than 40 percent of the samples. Because the sampling strategies for the more recent monitoring studies have focused on the analysis of areas which are susceptible to contamination, it is suggested that the apparent increasing trends are not representative of increased usage or emissions over time, but rather are a function of sample location. To develop a probabilistic description of environmental exposures and their ecological significance, the frequency distribution of environmental levels were compared to the U.S. EPA draft Water Quality Criteria for nonylphenol (NP), and to probabilistic descriptions of ecological effects as defined by species sensitivity distributions. Examination of the percent rank of aggregated APEO concentrations (adjusted according to their relative toxicities) suggests that less than 5% of the samples contained aggregate NP equivalent concentrations that exceed the criterion. A probabilistic risk assessment for total NP equivalent impact on U.S. aquatic ecosystems indicated that the likelihood of a surface water concentration exceeding the draft criterion for NP is approximately 6% or less, indicating an infrequent or low probability of occurrence.
WP099 (RIC-1117-753776) Effects of Statins and Selective Serotonin Reuptake Inhibitors (SSRI) on Chitobiase Expression of Zooplankton.
Start time: 8:00 AM
Belka, M1, Kelly, S1, Symes, S1, Zoerb, M1, Hanson, M2, Richards, S1, 1 Department of Biological and Environmental Sciences, The University of Tennessee at Chattanooga, Chattanooga, TN, USA2 Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba, Canada
Pharmaceuticals are being introduced into surface waters via raw sewage and treated sewage effluent. This widespread release has become an imperative issue problematic to global aquatic ecosystems. Since pharmaceuticals are designed to alter physiological mechanisms including hormonal regulation, concern about endocrine controlled development in organisms of surface waters receiving sewage effluent is warranted. The enzyme chitobiase is associated with development of aquatic invertebrates as it facilitates molting and subsequent growth. The aim of the present research is to assess the suitability of the chitobiase assay for use as a rapid, inexpensive, non-lethal screen of pharmaceutical effects on aquatic invertebrates, specifically Daphnia magna. Reduction in enzyme activity should be linked to reduced growth, survivorship and reproduction. This approach was used to further investigate the effects of statins and SSRIs on Daphnia magna which have been shown in our lab to affect reproduction at 1.0 g/L in 21-d life cycle tests. Consistent chitobiase results were obtained by testing as few as three organisms (in triplicate) per test solution. Initial results indicate that exposure to a statin and a SSRI individually affect Daphnia neonatal chitobiase expression at concentrations of 1.0 g/L in 48-h tests. Thus, 48-h Daphnia chitobiase expression appears to correlate with 21-d reproductive effects. Based on our findings, the chitobiase assay has the potential to be an efficient non-lethal assay that may be used to screen for potential reproductive effects in aquatic invertebrates. This threshold at which change in chitobiase activity occurs approaches that of pharmaceutical concentrations currently found in North American surface waters. The potential for the use of chitobiase as a non-lethal screening tool and the ecological relevance of our findings will be further discussed.
WP100 (STA-1117-830073) Considering enantiospecific effects of chiral pharmaceutical pollutants.
Start time: 8:00 AM
Stanley, J1, Ramirez, A1, Mottaleb, M1, Alvarez, M1, Chambliss, C1, Brooks, B1, 1 Baylor University, Waco, TX, USA
Many environmental xenobiotics, including several known environmental pharmaceutical pollutants are chiral molecules. Different enantiomers of a chiral compound may differ significantly in their respective fate, bioavailability, and toxicity. Despite this fact, these enantiospecific differences have largely been ignored, and monitoring for these compounds often has not included an assessment of enantiomer ratio. Propranolol (-blocker) and fluoxetine (SSRI) are commonly prescribed pharmaceuticals that are distributed as racemic mixtures and have been detected in surface waters and effluents at concentrations ranging from the ng/L to the low g/L range. Traditional whole effluent toxicity testing endpoints as well as behavioral (Pimephales promelas feeding rate after 7-day exposures; Daphnia magna grazing rate after 21-day exposures) and physiological (D. magna heart rate after 30 minute exposures) endpoints were used to assess the enantiospecific effects of these pharmaceuticals to model aquatic organisms. Our hypothesis was that the (S)-enantiomers of these two compounds would also be more toxic to the endpoints tested in P. promelas and D. magna because (S)-propranolol is known to be the most active form in mammals (up to 100x), (S)-fluoxetine is eliminated more slowly from the human body, and the (S)-enantiomer of norfluoxetine, the active desmethylated metabolite of fluoxetine, is more potent than (R)-norfluoxetine. Propranolol and fluoxetine treatment levels were verified using by HPLC-MS. Up to a five-fold difference in toxicity between enantiomers of these pharmaceuticals was observed. This suggests enantiospecific differences in bioavailability and toxicity should be considered in the risk assessment framework for emerging contaminants. The expected toxicity relationship of (S) > (R) was observed for these two drugs for P. promelas but not D. magna indicating mammalian pharmacological information may be more predictive for toxicity to aquatic vertebrates than invertebrates.
WP101 (RAM-1117-767824) HPLC-MS/MS methodology for determination of pharmaceuticals and personal care products in fish tissue.
Start time: 8:00 AM
Ramirez, A1, 3, Mottaleb, M1, 2, 3, Johnson, Robert4, Lewis, Russell4, Brooks, B2, 3, Chambliss, C1, 3, 1 Department of Chemistry and Biochemistry, Baylor University, Waco, Texas3 Center for Reservoir and Aquatic Systems Research, Baylor University, Waco, Texas2 Department of Environmental Studies, Baylor University, Waco, Texas4 Civil Aerospace Medical Institute, Federal Aviation Administration, Oklahoma City, OK
Recent studies indicate the presence of pharmaceuticals and personal care products (PPCPs) in water and sediments of effluent-dominated streams, which likely represent worse case environmental exposure scenarios for PPCPs. Subsequently, organisms residing in these systems may experience life time exposures to PPCPs. A sensitive and selective method utilizing high performance liquid chromatography in combination with tandem mass spectrometry (HPLC-MS/MS) has been developed to enable analysis of selected PPCPs in fish tissue. Reversed-phase separation of 25 compounds was achieved using a C18 column and a non-linear gradient consisting of 0.1% formic acid and methanol. Analytes were monitored using tandem mass spectrometry with either positive or negative electrospray ionization. The instrumental detection limits (signal-to-noise = 3) for a 10 uL injection ranged from 0.1-10 ug/L, depending on the analyte. Recovery of PPCPs from fish tissue was monitored as a function of the polarity and pH of the extraction solvent in order to identify optimal conditions for method sensitivity. The results of this systematic investigation will be presented along with preliminary analyses of fish collected from the Pecan Creek Water Reclamation Plant, Denton County, TX, USA.
WP102 (SIM-1117-828772) Interaction of stilbene compounds with the estrogen receptor.
Start time: 8:00 AM
Simmons, D1, Sherry, J2, Trudeau, V3, Balch, G4, Metcalfe, C4, 1 Trent University, Watershed Ecosystems Graduate Program2 Canadian Centre for Inland Waters, Burlington, Ontario, Canada3 University of Ottawa, Ottawa, Ontario, Canada4 Trent Unviersity, ERS Dept., Peterborough, Ontario, Canada
Stilbene-related pharmaceuticals and personal care products have been detected in sewage effluents and in surface waters. The effects of a range of stilbene-related personal care and pharmaceutical products and natural plant compounds were tested for interactions with the estrogen receptor (ER) using two in vitro assay systems; the yeast estrogenicity screening (YES) assay with a human estrogen receptor, and a reporter gene assay with the rainbow trout estrogen receptor (rtER) transfected into RTG-2 cells. Selected stilbene compounds were also tested in vivo in rainbow trout using the plasma vitellogenin biomarker. The results indicated that many of these compounds behave similarly to known ER inhibitors that have been developed for pharmaceutical applications (e.g.tamoxifen), and the most common structural similarity for these inhibitors, in addition to the stilbene backbone, is the presence of a 4-hydroxy phenyl group. Stilbene products found to act as inhibitors in the rtER in vitro assay include the plant-derived dietary supplement, resveratrol (IC50 = 1.11 x 10-5 M), and DSBP a fluorescent whitening agent that is a detergent additive (IC50 = 7.89 x 10-6 M). Additionally, the rainbow trout ER assay appeared to bind the stilbene compounds used in this study with less affinity and possibly specificity and affinity than the human ER. These results support current knowledge regarding fish ERs, and suggest that future toxicological assessments of environmental estrogens should be based upon technologies that assess chronic endpoints in order to more appropriately address the complexity of species interactions, contaminant mixtures and the effects of chronic low doses.
WP103 (PAU-1117-730119) Characterization of exposure of a tilapid (Oreochromis mossambicus) residing in a water reclamation facility.
Start time: 8:00 AM
Paulos, P1, LaPoint, T1, 1 University of North Texas, Denton, Texas, USA
Much recent research indicates that pharmaceutical and personal care products (PPCPs) are pervasive in wastewater treatment processes. An encompassing class of chemicals, PPCPs have been identified as problematic in laboratory exposures at very low concentrations, as low as ng/L. However, translation of laboratory studies to native populations has been largely unsuccessful. Toxicity studies incorporating whole-life histories of exposed organisms would greatly facilitate elucidation of potential effect these chemicals may have on native populations. In this regard, the City of Denton Pecan Creek Water Reclamation Plant introduced a population of Mozambique tilapia, Oreochromis mossambicus (Peters, 1852) in October of 2003 in an attempt to combat a burgeoning population of Lemna. Tilapia primarily reside in clarifier and sand filter areas of the facility, in water consisting of 100% treated effluent. Introduced tilapia have not only efficiently controlled Lemna growth, but are reproducing at prolific rates. Proposed research includes a comprehensive examination of possible consequence for fish exposed to this chemical soup. Research will incorporate an investigation of biomarkers - cortisol and vitellogenin, aspects and suitability of growth, and reproductive effect. An initial demographic study involving visual sexing of fish revealed an aggregate female:male ratio (N=1466) of 60.5:39.5, significantly different from expected (Log-likelihood – G test, = 0.05), but not unlike ratios observed in tilapia reared in cooler (20°C) temperatures. As a warm water species, sexual differentiation in tilapia is influenced by temperature, with warmer water producing a preponderance of males, cooler water more females. Ensuing research will prove beneficial in explaining impact of wastewater effluent at population levels as manifested in resident species.
WP104 (GAG-1115-727672) Occurrence of pharmaceutical products in a municipal effluent and toxicity to rainbow trout hepatocytes.
Start time: 8:00 AM
Gagné, F1, Blaise, C1, André, C1, 1 Environment Canada, Montreal, Québec, Canada
Pharmaceutical and personal care products (PPCPs) are found in municipal effluents and represent the major source of contamination for the aquatic environment. The purpose of this study was to examine the cytotoxic and oxidative effects of these products and other wastewater-related products (i.e. coprostanol, cotinine, estradiol, nonylphenol and cholesterol) in primary cultures of rainbow trout hepatocytes. The redox activity of various PPCPs in trout (Oncorhynchus mykiss) liver microsomes was investigated in vitro by following the rate of oxidation of NADPH and the formation of lipid peroxidation (LPO) after a 60-min incubation period. In addition, primary cultures of rainbow trout hepatocytes were exposed to various drugs identified in the municipal effluent for 48h at 15oC. Our results show that most PPCPs (83%) accelerated the rate of NADPH oxidation in the presence of microsomes and 72% of them increased LPO in microsomal membranes. LPO levels was significantly correlated (R = 0.5; p < 0.05) with the number of functional groups present on the molecule (i.e. number of O, S, N, P/number of C and H) and negatively so (R = -0.44; p < 0.05) with the octanol/water partition coefficient, suggesting that nucleophilicity and hydrophobicity are related to oxidative activity for these compounds. Exposure of trout hepatocytes to these products decreased cell viability, increased CYP3A-related monooxygenase activity (benzylether resorufin dealkylase), and LPO. No induction of CYP1A1-related activity (7-ethoxyresrufin O-deethylase) was observed. Moreover, municipal effluent extracts (ethanol) were able to increase all the above responses in a dose-dependent manner, suggesting the presence of drug-like effects in these complex mixtures. These results suggest that the basic redox properties of PPCPs could influence oxidative metabolism in liver cells and lead to oxidative damage. These products have the potential to produce a toxic response in aquatic organisms and the above biomarkers were shown to readily respond to PPCPs in aquatic organisms.
WP105 (MUR-1117-823411) Mechanism and environmental ubiquity of the novel ipf pathway for the degradation of ibuprofen and related aromatic acids.
Start time: 8:00 AM
Murdoch, R1, Hay, A1, 1 Cornell Institute for Comparative and Environmental Toxicology, Ithaca, NY, USA
Sphingomonas Ibu-2 has been shown in previous studies to metabolize ibuprofen (2-(4-isobutylphenyl)-propionic acid) and related aromatic acids through a novel metabolic pathway involving removal of the acidic sidechain. Metabolites produced by activity-deficient mutants have been analyzed by HPLC and mass spectroscopy in order to gain insight into the mechanism of this unusual pathway. In addition, a number of other environmental isolates have been found to metabolize ibuprofen through an apparently similar mechanism. This type of reaction, if found to be widespread, could alter our understanding and predictions of how various aromatic acids are metabolized by bacteria, especially given the fact that the phenylacetate core of ibuprofen is common to many other non-steroidal anti-inflammatory pharmaceuticals.
WP106 (KIM-1117-807811) Sorption of male hormones by soils and sediments.
Start time: 8:00 AM
Kim, I1, Huang, W1, 1 Rutgers University, New Brunswick, NJ, USA
Testosterone and androstenedione are steroid hormones ubiquitously found in the environment. Major sources of the two androgens are animal manures and sewage effluents and their presence in ecosystems is a growing concern. Testosterone is the primary steroid hormone while its biological precursor, androstenedione, is suspected to be the metabolite. In this study, we examined the sorption characteristics of the two chemicals on four soil/sediment samples at both equilibrium and rate-limiting conditions. Our results reveal that sorption equilibrium is reached at 14 days for a peat and 5 days for a soil when the initial androgen concentrations (Co) were at 17 percent of their solubility limits (Sw). However, when the Co was 0.5 percent of their Sw, equilibrium was attained in 21 days for peat and 10 days for soil. The measured sorption isotherms were all nonlinear, with the Freundlich model n parameter ranging from 0.698 to 0.899. At Ce = 0.04 Sw, the log Koc values (L/g) for testosterone and androstenedione ranged from 2.57 to 3.29 and 2.9 to 3.78, whereas at Ce = 0.002 Sw, the log Koc values ranged from 2.89 to 3.34 and 3.18 to 4.32, respectively. Because the concentrations of androgens in the environments are much lower than their Sw, it is expected that sorption equilibrium will take even longer to achieve and that the log Koc will subsequently be greater. The greater sorption distribution coefficients at lower aqueous phase concentrations indicate that these chemicals may be more sorptive and less bioavailable at the environmental conditions.