Recent Science Inventory records from the EPA

PARTICULATE MATTER NAAQS REVIEW: INTEGRATED SCIENCE ASSESSMENT

Mon, 23 Nov 2009 19:49:31 GMT

Particulate matter (PM) is a complex mixture of extremely small particles and liquid droplets. PM is one of six common air pollutants for which EPA has issued air quality criteria and established national ambient air quality standards (NAAQS). The integrated science assessment (ISA) is one of the four major elements of the PM NAAQS review process. The ISA will provide a concise evaluation, integration and interpretation of the most policy-relevant scientific information on the health and environmental effects of PM. The ISA will provide the scientific foundation for risk and exposure assessments and regulatory decision-making on the NAAQS for PM.

Sustainable Alternatives for the Synthesis of Organics and Nanomaterials

Mon, 23 Nov 2009 19:12:32 GMT

The presentation summarizes recent activity in eco-friendly chemical synthesis, which involves benign alternatives, such as the use of supported reagents, and greener reaction medium in aqueous or solvent-free conditions. The synthesis of heterocyclic compounds, coupling reactions, and a variety of name reactions2 are the primary beneficiaries as exemplified by the synthesis of N-aryl azacycloalkanes, isoindoles, and dihydropyrazoles, 1,3,4-oxadiazoles, 1,3,4-thiadiazoles, 1,3-dioxanes, pyrazoles, catalyzed by basic water or polystyrene sulfonic acid (PSSA) in aqueous media or under solvent-free MW conditions. Shape-controlled aqueous synthesis of noble nanostructures via benign methods using vitamins and MW-assisted spontaneous reduction of noble metal salts using sugars and glutathione will be presented. A general MW method has been developed that accomplishes the cross-linking reaction of poly (vinyl alcohol) (PVA) with metallic systems such as Pt, Cu, and In; bimetallic systems, namely Pt-In, Ag-Pt, Pt-Fe, Cu-Pd, Pt-Pd and Pd-Fe; and SWNT, MWNT, and C-60. The strategy is extended to the formation of biodegradable carboxymethyl cellulose (CMC) composite films with noble nanometals; such metal decoration and alignment of carbon nanotubes in CMC is possible using MW approach which also enables the shape-controlled bulk synthesis of Ag and Fe nanorods in poly (ethylene glycol). MW hydrothermal process delivers magnetic nanoferrites4 and micro-pine structured catalysts are also obtainable in water from readily available metal salts. The sustainable generation of nano particles and their applications in catalysis will be highlighted.

Green synthesis of Fe0 and bimetallic Fe0 for oxidative catalysis and reduction applications

Mon, 23 Nov 2009 19:10:48 GMT

A single-step green approach to the synthesis of nanoscale zero valent iron (nZVI) and nanoscale bimetallic (Fe0/Pd) particles using tea (Camellia sinensis) polyphenols is described. The expedient reaction between polyphenols and ferric chloride (FeCl3) occurs within a minute at room temperature and is indicated by a color change from pale yellow to dark green/black as the iron nanoparticles are formed. Tea polyphenols form complexes with metal ions in solution and reduce them to nanoscale iron. The synthesis of bimetallic catalysts, with PdCl2 acting as a co-metal which coats the outer layer of the nanoscale iron particles, increases both catalytic oxidative and reductive potential for environmental treatment applications. The green synthesis method is general and single and bimetallic catalysts may be extended to other noble metals such as gold (Au) and platinum (Pt). Specific examples using hydrogen peroxide and sodium persulfate to generate free radical oxidant species indicates that these green synthesized nZVI and Fe0/Pd catalysts provide significantly more efficient contaminant degradation compared to Fe-EDTA and Fe-EDDS.

IRIS TOXICOLOGICAL REVIEW AND SUMMARY DOCUMENTS FOR ETHYLENE OXIDE'S CARCINOGENICITY

Mon, 23 Nov 2009 18:26:18 GMT

The known carcinogenic effects of ethylene oxide will be summarized, with citations from current scientific literature. A hazard characterization consisting of a weight-of-evidence and dose-response relationships including if appropriate cancer unit risk factor(s) will be developed. The assessment documents will be peer reviewed within the Agency and by experts outside the Agency according to the established IRIS procedures. For up-to-date project schedules see IRIS Track at http://cfpub.epa.gov/iristrac/index.cfm

IRIS TOXICOLOGICAL REVIEW AND SUMMARY DOCUMENTS FOR METHYL TERT-BUTYL ETHER (MTBE)

Mon, 23 Nov 2009 18:20:05 GMT

MTBE is a volatile organic chemical used to oxygenate gasoline. Oxygenated gasoline improves the exhaust emissions from gasoline engines. Since 1992 it has been used to comply with the Federal Reformulated Gasoline (begun in 1995) and Wintertime Oxygenated Fuel (begun in 1992) programs under the Clean Air Act. A total of 26 States have areas required to participate in these programs. Although some evaporates, MTBE moves readily through soil into water and degrades more slowly than many other gasoline components. This is a particular problem when MTBE containing gasoline is stored in underground tanks and the tanks leak. This assessment evaluates the potential health risks of MTBE in light of the available information and will characterize the key cancer and non cancer health effect hazards from inhalation and oral exposure. This will update a 1993 IRIS RfC, but will be the first entry for an RfD and a cancer characterization. For up-to-date project schedules see IRIS Track at http://cfpub.epa.gov/iristrac/index.cfm

IRIS TOXICOLOGICAL REVIEW AND SUMMARY DOCUMENTS FOR TETRACHLOROETHYLENE

Mon, 23 Nov 2009 18:12:05 GMT

The known toxic effects of perchloroethylene will be summarized, with citations from current scientific literature. The critical effects will be identified, and from this the RfD and RfC and cancer unit risk factors will be derived. The RfD and RfC are reference doses and air concentrations that are generally regarded as safe under conditions of chronic exposure. The cancer unit risks in air and drinking water are the estimated lifetime cancer risks expected to occur from a lifetime exposure to a concentration of 1 microgram per cubic meter in the air and to a drinking water concentration of 1 microgram per liter. This summary document will be peer reviewed within the Agency and by experts outside the Agency according to the standard IRIS procedures. For up-to-date project schedules see IRIS Track at http://cfpub.epa.gov/iristrac/index.cfm

EXTERNAL REVIEW DRAFT OF CANCER HAZARD CHARACTERIZATION FOR LIBBY MONTANA AMPHIBOLE (Asbestos)

Mon, 23 Nov 2009 17:57:28 GMT

A health assessment document will be prepared to characterize the potential cancer health hazards from exposure to asbestos present in Libby Montana. The asbestos is naturally occurring in vermiculite material that was historically mined in Libby. Because of the asbestos contamination in the Libby area and resultant population exposure, Libby is a designated EPA Superfund site under Region 8 jurisdiction. The assessment and characterization will focus on the form of asbestos present in Libby and will make use of Libby specific data as well as other general asbestos data. The intent is to develop both a hazard and dose-response evaluation leading to a weight of evidence conclusion about the scope of the human cancer hazard and, as appropriate, develop an estimate of cancer unit risk or some other metric that will benchmark risk per unit of exposure. These types of findings can then be used by others who have exposure data to estimate population cancer risk. Data to be evaluated will include long and short term animal studies, epidemiologic studies, as well as related studies for mode of action, pharmacokinetics and other biomedical data. The assessment will be prepared by EPA scientists with assistance from outside experts as warranted. The assessment will resemble an IRIS Toxicological Profile and eventually could be summarized so that it could be entered into EPA's IRIS data base specific to the Libby amphibole. The external review draft will be peer reviewed and finalized per Agency procedures. The external peer review mechanism is yet to be determined.

AUTOMATED GEOSPATIAL WATERSHED ASSESSMENT (AGWA): A GIS-BASED TOOL FOR WATERSHED ASSESSMENT AND PLANNING

Mon, 23 Nov 2009 17:23:37 GMT

The Automated Geospatial Watershed Assessment tool (AGWA) is a GIS interface jointly developed by the USDA Agricultural Research Service, the U.S. Environmental Protection Agency, the University of Arizona, and the University of Wyoming to automate the parameterization and execution of the Soil Water Assessment Tool (SWAT) and KINEmatic Runoff and EROSion (KINEROS2) hydrologic models. The application of these two models allows AGWA to conduct hydrologic modeling and watershed assessments at multiple temporal and spatial scales. AGWA?s current outputs are runoff (volumes and peaks) and sediment yield, plus nitrogen and phosphorus with the SWAT model. AGWA uses commonly available GIS data layers to fully parameterize, execute, and visualize results from both models. Through an intuitive interface the user selects an outlet from which AGWA delineates and discretizes the watershed using a Digital Elevation Model (DEM) based on the individual model requirements. The watershed model elements are then intersected with soils and land cover data layers to derive the requisite model input parameters. The chosen model is then executed, and the results are imported back into AGWA for visualization. This allows managers to identify potential problem areas where additional monitoring can be undertaken or mitigation activities can be focused. AGWA also has tools to apply an array of best management practices. There are currently two versions of AGWA available; AGWA 1.5 for users with Environmental Systems Research Institute (ESRI) ArcView 3.x and AGWA 2.0 for users with ESRI ArcGIS 9.x. For more information on AGWA visit website located at: http://www.tucson.ars.ag.gov/agwa/ or http://www.epa.gov/nerlesd1/land-sci/agwa/index.htm.

AUTOMATED GEOSPATIAL WATERSHED ASSESSMENT (AGWA): A GIS-BASED HYDROLOGIC MODELING TOOL FOR WATERSHED ASSESSMENT AND ANALYSIS

Mon, 23 Nov 2009 17:16:31 GMT

Optimization of an Isolated Perfused Rainbow Trout Liver Model: Clearance Studies with 7-Ethoxycoumarin

Mon, 23 Nov 2009 16:44:35 GMT

Isolated trout livers were perfused using methods designed to preserve tissue viability and function. Liver performance was evaluated by measuring O2 consumption (VO2), vascular resistance, K+ leakage, glucose flux, lactate flux, alanine aminotransferase (ALT) leakage, and metabolic clearance of 7-ethoxycoumarin (CLH,7-EC). VO2 immediately following isolation was increased by the addition of pyruvate and EDTA to the liver clearing solution. Maximal rates of VO2 during the post-recovery period were observed at perfusion rates of 1.0 mL/min/g-liver or higher. Livers perfused with solutions containing 1.0, 2.5, or 10.0 g/L bovine serum albumin (BSA) exhibited relatively stable physiological performance for up to 10 h. CLH,7-EC appeared to decrease rapidly during the first 1-2 h, probably due in part to non-steady-state conditions. CLH,7-EC declined slowly thereafter, decreasing by 30 to 40% between 2 and 10 h. A linear equation was subsequently developed to correct measured levels of clearance for this decrease in metabolic activity over time. To illustrate the value of this preparation, experiments were conducted to examine the effects of protein binding on hepatic clearance of 7-EC. Clearance rates corrected for declining metabolic activity (CLH,7-EC,CORR) changed in nearly direct proportion to changes in the free concentration of 7-EC efferent to the liver, as predicted by theoretical models of liver function. Additional studies were performed to characterize the concentration-dependence of 7-EC metabolism. Metabolic activity increased linearly with the total concentration of 7-EC afferent to the liver resulting in constant levels of CLH,7-EC,CORR? CLH,7-EC,CORR values for four livers averaged 12.0 ± 5.0 mL/h/g-liver (mean ± SD, n= 60 individual determinations) and were in good agreement with an estimate of hepatic clearance obtained by extrapolating published in vitro data from isolated trout hepatocytes. The extended viability of isolated trout livers achieved in this study creates new opportunities for research on hepatic function if fish.

AN INEXPENSIVE AUTOSAMPLER AND FIELD SAMPLE CARRIER TO PROVIDE SEMI-QUANTITATIVE MAPS FOR DISPERSED CHEMICALS WITH HIGH SPATIAL RESOLUTION USING AMBIENT-AIR MASS SPECTROMETRY

Mon, 23 Nov 2009 16:32:28 GMT

There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact Field.

Protein Carbonyl Formation in Response to Propiconazole-Induced Oxidative Stress.

Mon, 23 Nov 2009 16:30:20 GMT

Propiconazole, a widely used fungicide, is hepatotoxic and hepatotumorigenic in mice. Previous genomic analysis of liver tissues from propiconazole-treated mice identified genes and pathways involved in oxidative stress, suggesting that oxidative stress may play a role in propiconazole-induced toxicity. To understand the contribution of oxidative stress on toxicity at the protein level, we developed an integrated approach for the systematic measurement of protein oxidation in the livers from propiconazole-treated mice. Liver protein carbonylation increased significantly after treatment with propiconazole, demonstrating propiconazole-associated induction of oxidative stress. Utilizing two-dimensional gel electrophoresis (2-DE), immunoblotting, and mass spectrometry, we identified 17 carbonylated proteins that were altered with varying intensities by propiconazole treatment. The potential effects of protein carbonylation on protein functions and cellular activities in the liver of propiconazole-treated mice were further investigated. A significant negative correlation between protein carbonylation and cytochrome c reductase activity was found. We conclude that glycolysis, mitochondrial respiratory chain, ATP production, amino acid metabolism, CO2 hydration, cellular antioxidant defense and detoxification system, tetrahydrobiopterin pathways are affected by oxygen radicals in the livers of propiconazole-treated mice. This study suggests a mode of propiconazole-induced toxicity in mouse liver which primarily involves oxidative damage to cellular proteins.

Discrimination of tumorigenic triazole conazoles from phenobarbital by transcriptional analyses of mouse liver gene expression

Mon, 23 Nov 2009 16:28:50 GMT

Conazoles are fungicides used to control fungal growth in environmental settings and to treat humans with fungal infections. Mouse hepatotumorigenic conazoles display many of the same hepatic toxicologic responses as the mouse liver carcinogen phenobarbital (PB): constitutive androstane receptor (CAR) activation, hypertrophy, Cyp2b induction, and increased cell proliferation. The goal of this study was to apply transcriptional analyses to hepatic tissues from mice exposed to PB, propiconazole (Pro) or triadimefon (Tri) at tumorigenic exposure levels to reveal similarities and differences in response among these treatments. Mice were administered diets containing PB (850 ppm), Pro (2500 ppm), or Tri (1800 ppm) for 4 and 30 days. Targeted transcriptomic analyses were conducted at the gene level examining differentially expressed genes (DEGs), and subsets of DEGs: cell cycle genes, and transcription factors. Analyses were also conducted on function, pathway and network levels examining Ingenuity Pathway Analysis Tox Lists and Canonical Pathways, and Gene-Go MetaCore dynamic networks and their central hubs. Genes expressed by PB or the two conazoles were also compared with those genes associated with human hepatocellular cancer. The results from these analyses indicated greater differences between PB and the two conazoles than similarities. Significant commonalities between the two conazole treatments were also noted. We posit that the transcriptional profiles of tissues exposed to toxic chemicals inherently contain their mechanisms of toxicity. We conclude that although PB and these 2 conazoles induce mouse liver tumors and exhibit similar toxicological responses, their transcriptional profiles are significantly different and thus their mechanisms of tumorigenic action are likely to differ.

A Bioassessment Approach for Mid-continent Great Rivers: The Upper Mississippi, Missouri, and Ohio (USA)

Mon, 23 Nov 2009 13:55:04 GMT

This work describes EPA's Environmental Monitoring and Assessment Program for Great Rivers (EMAP-GRE).

RISK ASSESSMENT SUPPORTING THE FINAL RULE FOR SOLVENT-CONTAMINATED WIPES

Mon, 23 Nov 2009 12:54:47 GMT

This analysis evaluates potential risks due to release of solvents from laundry sludge and disposable wipes sent to a landfill. Receptors for air and groundwater in lined and unlined landfills were evaluated. The potential solvent concentrations were calculated to determine the solvent loadings from the wipes and sludge. The mass based solvent quantity loadings were compared to the risk based loadings to determine the risk potential for specific solvents. This risk analysis also addressed previous peer reviewers? and general public comments on the initial risk assessment conducted for the proposed rule. The final rule, supported by the risk assessment, will be prepared after the consideration of all comments for the proposed rule and the risk analysis Notice of Data Availability.

IMPLICATIONS OF USING ROBUST BAYESIAN ANALYSIS TO REPRESENT DIVERSE SOURCES OF UNCERTAINTY IN INTEGRATED ASSESSMENT

Mon, 23 Nov 2009 06:28:22 GMT

In our previous research, we showed that robust Bayesian methods can be used in environmental modeling to define a set of probability distributions for key parameters that captures the effects of expert disagreement, ambiguity, or ignorance. This entire set can then be updated against data using Bayes? theorem to investigate the degree to which aleatory and/or epistemic uncertainty are reduced through additional observations. Further work is required to clarify the methods of selecting the appropriate set definitions in real-world applications. Such work addresses the first objective of the proposed project. In parallel research, we have demonstrated that economic analyses performed under conditions of uncertainty require specific, and previously unrecognized, methods and rates for discounting future benefits. We plan for our second objective to lead to a delineation of the exact consequences of this result for integrated assessment modeling. Finally, we hypothesize that the above two outcomes will have significant implications for decision support. This will be tested using the integrated robust Bayesian network to evaluate policies according to both conventional and alternative decision criteria.