Environmental Health and Protection Commons^™

Seasonal Fecundity Is Not Related To Geographic Position Across A Species’ Global Range Despite A Central Peak In Abundance, Katharine J. Ruskin, Matthew A. Etterson, Thomas P. Hodgman, Alyssa C. Borowske, Jonathan B. Cohen, Chris S. Elphick, Christopher R. Field, Rebecca A. Kern, Erin King, Alison R. Kocek, Adrienne I. Kovach, Kathleen M. O’Brien, Nancy Pau, W. Gregory Shriver, Jennifer Walsh, Brian J. Olsen

United States Environmental Protection Agency: Staff Publications

The range of a species is determined by the balance of its demographic rates across space. Population growth rates are widely hypothesized to be greatest at the geographic center of the species range, but indirect empirical support for this pattern using abundance as a proxy has been mixed, and demographic rates are rarely quantified on a large spatial scale. Therefore, the texture of how demographic rates of a species vary over its range remains an open question. We quantified seasonal fecundity of populations spanning the majority of the global range of a single species, the saltmarsh sparrow (Ammodramus caudacutus …

Using Ecological Production Functions To Link Ecological Processes To Ecosystem Services, Randall Jf Bruins, Timothy J. Canfield, Clifford Duke, Larry Kapustka, Amanda M. Nahlik, Ralf B. Schäfer

United States Environmental Protection Agency: Staff Publications

Ecological production functions (EPFs) link ecosystems, stressors, and management actions to ecosystem services (ES) production. Although EPFs are acknowledged as being essential to improve environmental management, their use in ecological risk assessment has received relatively little attention. Ecological production functions may be defined as usable expressions (i.e., models) of the processes by which ecosystems produce ES, often including external influences on those processes. We identify key attributes of EPFs and discuss both actual and idealized examples of their use to inform decision making. Whenever possible, EPFs should estimate final, rather than intermediate, ES. Although various types of EPFs have been …

Influence Of Resource Availability On Juniperus Virginiana Expansion In A Forest–Prairie Ecotone, A. C. Ganguli, D. M. Engle, P. M. Mayer, L. F. Salo

United States Environmental Protection Agency: Staff Publications

Woody plant expansion into grasslands and savannas is a global concern. Rapid expansion of Juniperus virginiana, a tree native to North America, has profound ecological consequences. We used transplanted J. virginiana seedlings to investigate the role of resource availability on J. virginiana expansion following the removal of fire, the factor historically limiting range expansion of this fire-intolerant species. We evaluated J. virginiana seedling survival and seedling growth, two important phases in woody plant expansion, relative to two below ground resource factors, plant-available soil water (soil clay content, an index of plant-available soil water) and plant-available nitrogen (PAN), and an above …

A Comparison Between 2010 And 2006 Air Quality And Meteorological Conditions, And Emissions And Boundary Conditions Used In Simulations Of The Aqmeii-2 North American Domain, Till E. Stoeckenius, Christian Hogrefe, Justin Zagunis, Timonthy M. Sturtz, Benjamin Wells, Tanarit Sakulyanontvittaya

United States Environmental Protection Agency: Staff Publications

Several participants in Phase 2 of the Air Quality Model Evaluation International Initiative (AQMEII-2) who are applying coupled models to the North American domain are comparing model results for two years, 2006 and 2010, with the goal of performing dynamic model evaluation. From a modeling perspective, the differences of interest are the large reductions in domain total emissions of NO_x (21%) and SO₂ (37%) from 2006 to 2010 and significant differences in meteorological conditions between these two years. The emission reductions occurred mostly in the eastern U.S, with some reduction in emissions from western wildfires in 2010. Differences …

Seasonality Of Coliform Bacteria Detection Rates In New Jersey Domestic Wells, Thomas B. Atherholt, Nicholas A. Procopio, Sandra M. Goodrow

United States Environmental Protection Agency: Staff Publications

It is important that indicators of fecal pollution are reliable. Coliform bacteria are a commonly used indicator of fecal pollution. As other investigators have reported elsewhere, we observed a seasonal pattern of coliform bacteria detections in domestic wells in New Jersey. Examination of a statewide database of 10 years of water quality data from 93,447 samples, from 78,207 wells, generated during real estate transactions, revealed that coliform bacteria were detected in a higher proportion of wells during warm weather months. Further examination of the seasonal pattern of other data, including well water pH, precipitation, ground and surface water temperatures, surface …

Alpha-Lipoic Acid Supplementation Protects Enzymes From Damage By Nitrosative And Oxidative Stress, Sylvia Hiller, Robert Dekroon, Eric D. Hamlett, Longquan Xu, Cristina Osorio, Jennifer Robinette, Witold Winnik, Stephen Simington, Nobuyo Maeda, Oscar Alzate, Xianwen Yi

United States Environmental Protection Agency: Staff Publications

Background: S-nitrosylation of mitochondrial enzymes involved in energy transfer under nitrosative stress may result in ATP deficiency. We investigated whether α-lipoic acid, a powerful antioxidant, could alleviate nitrosative stress by regulating S-nitrosylation,which could result in retaining themitochondrial enzyme activity.

Methods: In this study, we have identified the S-nitrosylated forms of subunit 1 of dihydrolipoyllysine succinyltransferase (complex III), and subunit 2 of the α-ketoglutarate dehydrogenase complex by implementing a fluorescence-based differential quantitative proteomics method.

Results: We found that the activities of these two mitochondrial enzymes were partially but reversibly inhibited by S-nitrosylation in cultured endothelial cells, and that their activities …

Estimating Ozone And Secondary Pm2.5 Impacts From Hypothetical Single Source Emissions In The Central And Eastern United States, Kirk R. Baker, Robert A. Kotchenruther, Rynda C. Hudman

United States Environmental Protection Agency: Staff Publications

Secondary pollutant impacts from emissions of single sources may need to be assessed to satisfy a variety of regulatory requirements including the Clean Air Act New Source Review and Prevention of Significant Deterioration programs and the National Environmental Policy Act. In this work, single source impacts on O₃ and secondary PM_2.5 are estimated with annual 2011 photochemical grid model simulations where new hypothetical sources are added to the central and eastern United States with varying precursor emission rates and emission release heights. Impacts from these hypothetical sources are tracked with photochemical grid model source apportionment. Single source impacts …

Temporal Trends In The Spatial Distribution Of Impervious Cover Relative To Stream Location, J. Wickham, A. Neale, M. Mehaffey, T. Jarnagin, D. Norton

United States Environmental Protection Agency: Staff Publications

Use of impervious cover is transitioning from an indicator of surface water condition to one that also guides and informs watershed planning and management, including Clean Water Act (33 U.S.C. §1251 et seq.) reporting. Whether it is for understanding surface water condition or planning and management, impervious cover is most commonly expressed as summary measurement (e.g., percentage watershed in impervious cover). We use the National Land Cover Database to estimate impervious cover in the vicinity of surface waters for three time periods (2001, 2006, 2011). We also compare impervious cover in the vicinity of surface waters to watershed summary estimates …

Carbon Storage In Us Wetlands, A. M. Nahlik, M. S. Fennessy

United States Environmental Protection Agency: Staff Publications

Wetland soils contain some of the highest stores of soil carbon in the biosphere. However, there is little understanding of the quantity and distribution of carbon stored in our remaining wetlands or of the potential effects of human disturbance on these stocks. Here we use field data from the 2011 National Wetland Condition Assessment to provide unbiased estimates of soil carbon stocks for wetlands at regional and national scales. We find that wetlands in the conterminous United States store a total of 11.52 PgC, much of which is within soils deeper than 30 cm. Freshwater inland wetlands, in part due …

Water Consumption Estimates Of The Biodiesel Process In The Us, Qingshi Tu, Mingming Lu, Y. Jeffrey Yang, Don Scott

United States Environmental Protection Agency: Staff Publications

As a renewable alternative to petroleum diesel, biodiesel has been widely used in the US and the world. However, its potential impact on water resources has not been much evaluated. This study investigates water consumption from the biodiesel process, which includes three stages: soybean irrigation, soybean-to-soybean oil processing, and biodiesel manufacturing, at both national and state levels. Mass-based allocation is performed and water consumption at the three stages is obtained on the basis of million gallons per year and gallon water per gallon biodiesel (gal/gal). The normalized water consumption (water intensity) of the irrigation, oil processing, and biodiesel production stages …

Quantitative Structure–Mesothelioma Potency Model Optimization For Complex Mixtures Of Elongated Particles In Rat Pleura: A Retrospective Study, Philip M. Cook, Joseph Swintek, Timothy D. Dawson, David Chapman, Mathew A. Etterson, Dale Hoff

United States Environmental Protection Agency: Staff Publications

Cancer potencies of mineral and synthetic elongated particle mixtures, including asbestos fibers, are influenced by changes in fiber dose composition, bioavailability, and biodurability in combination with relevant cytotoxic dose-response relationships. An extensive rat intrapleural dose characterization data set with a wide variety of elongated particles physicochemical properties facilitated statistical analyses of pleural mesothelioma response data combined from several studies for evaluation of alternative dose-response models. Utilizing logistic regression of individual elongated particle dimensional variations within each test sample, four major findings emerged: (1) Mild acid leaching provides superior prediction of tumor incidence compared to samples that were not leached; (2) …

Potential Aquifer Vulnerability In Regions Down-Gradient From Uranium In Situ Recovery (Isr) Sites, James A. Saunders, Bruce E. Pivetz, Nathan Voorhies, Richard T. Wilkin

United States Environmental Protection Agency: Staff Publications

Sandstone-hosted roll-front uranium ore deposits originate when U(VI) dissolved in groundwater is reduced and precipitated as insoluble U(IV) minerals. Groundwater redox geochemistry, aqueous complexation, and solute migration are important in leaching uranium from source rocks and transporting it in low concentrations to a chemical redox interface where it is deposited in an ore zone typically containing the uranium minerals uraninite, pitchblende, and/or coffinite; various iron sulfides; native selenium; clays; and calcite. In situ recovery (ISR) of uranium ores is a process of contacting the uranium mineral deposit with leaching and oxidizing (lixiviant) fluids via injection of the lixiviant into wells …

Identification Of Putative Geographically Isolated Wetlands Of The Conterminous United States, Charles R. Lane, Ellen D'Amico

United States Environmental Protection Agency: Staff Publications

Geographically isolated wetlands (GIWs) are wetlands completely surrounded by uplands. While common throughout the United States (U.S.), there have heretofore been no nationally available, spatially explicit estimates of GIW extent, complicating efforts to understand the myriad biogeochemical, hydrological, and habitat functions of GIWs and hampering conservation and management efforts at local, state, and national scales. We used a 10-m geospatial buffer as a proxy for hydrological or ecological connectivity of National Wetlands Inventory palustrine and lacustrine wetland systems to nationally mapped and available stream, river, and lake data. We identified over 8.3 million putative GIWs across the conterminous U.S., encompassing …

Cyanotoxins In Inland Lakes Of The United States: Occurrence And Potential Recreational Health Risks In The Epa National Lakes Assessment 2007, Keith A. Loftin, Jennifer L. Graham, Elizabeth D. Hillborn, Sarah C. Lehmann, Michael T. Meyer, Julie E. Dietze, Christopher B. Griffith

United States Environmental Protection Agency: Staff Publications

A large nation-wide survey of cyanotoxins (1161 lakes) in the United States (U.S.) was conducted during the EPA National Lakes Assessment 2007. Cyanotoxin data were compared with cyanobacteria abundance- and chlorophyll-based World Health Organization (WHO) thresholds and mouse toxicity data to evaluate potential recreational risks. Cylindrospermopsins, microcystins, and saxitoxins were detected (ELISA) in 4.0, 32, and 7.7% of samples with mean concentrations of 0.56, 3.0, and 0.061 mg/L, respectively (detections only). Co-occurrence of the three cyanotoxin classes was rare (0.32%) when at least one toxin was detected. Cyanobacteria were present and dominant in 98 and 76% of samples, respectively. Potential …