United States Environmental Protection Agency

About: United States Environmental Protection Agency is a government organization based out in Washington D.C., District of Columbia, United States. It is known for research contribution in the topics: Population & Environmental exposure. The organization has 13873 authors who have published 26902 publications receiving 1191729 citations. The organization is also known as: EPA & Environmental Protection Agency.

Separation technologies for the recovery and dehydration of alcohols from fermentation broths

Abstract: Multi-column distillation followed by molecular sieve adsorption is currently the standard method for producing fuel-grade ethanol from dilute fermentation broths in modern corn-to-ethanol facilities. As the liquid biofuels industry transitions to lignocellulosic feedstocks, expands the end-product portfolio to include other alcohols, and encounters more dilute alcohol concentrations, alternative separation technologies which are more energy efficient than the conventional approach will be in demand. In this review, alcohol recovery technology options and alcohol dehydration technology options for the production of ethanol and 1-butanol are reviewed and compared, with an emphasis on the energy footprint of each approach. Select hybrid technologies are also described. Published in 2008 by John Wiley & Sons, Ltd

Effects of climate warming on fish thermal habitat in streams of the United States

Abstract: The effects of climate warming on the thermal habitat of 57 species of fish of the U.S. were estimated using results for a doubling of atmospheric carbon dioxide that were predicted by the Canadian Climate Center general circulation model. Baseline water temperature conditions were calculated from data collected at 1,700 U.S. Geological Survey stream monitoring stations across the U.S. Water temperatures after predicted climate change were obtained by multiplying air temperature changes by 0.9, a factor based on several field studies, and adding them to baseline water temperatures at stations in corresponding grid cells. Results indicated that habitat for cold and cool water fish would be reduced by -5O%, and that this effect would be distributed throughout the existing range of these species. Habitat losses were greater among species with smaller initial distributions and in geographic regions with the greatest warming (e.g. the central Midwest). Results for warm water fish habitat were less certain because of the poor state of knowledge regarding their high and low temperature tolerances; however, the habitat of many species of this thermal guild likely will also be substantially reduced by climate warming, whereas the habitat of other species will be increased. The threat of global climate change has stimulated the publication of numerous research papers dealing with the potential effects of surface and groundwater warming on the thermal habitat of freshwater fish (e.g. Coutant 1990; Magnuson et al. 1990; Meisner 1990; Stefan et al. 1995). With few exceptions (e.g. Shuter and Post 1990), most of these studies deal with responses to temperature in single water bodies or small geographic regions, so we decided to attempt an assessment of effects at a much larger scale consisting of the lower 48 states. Most of the studies cited above also dealt with effects of climate change on lake fish or habitat. We expected that using less detailed input data would keep the analysis manageable, but that we would use information compiled for or generated from previous smaller scale studies. These existing data include a quality-assured database of historical surface water temperature maxima at U.S. Geological Survey (USGS) stream monitoring stations and maximum temperature tolerances estimated from a field database for several dozen freshwater species of fish, as reported by Eaton et al. (1995); results of analyses of the relationship between air temperature and stream-water temperatures (Stefan and Preud’hommc 1993; Sinokrot and Stefan 1993); and a

Exposure of Americans to polybrominated diphenyl ethers.

Abstract: Polybrominated diphenyl ethers, PBDEs, are a class of brominated flame retardants that, like other persistent organic pollutants (POPs), have been found in humans, wildlife, and biota worldwide. Unlike other POPs, however, the key routes of human exposure are not thought to be food and fish, but rather are from their use in household consumer products, and to the high levels of PBDEs found in house dust. The exposure of Americans to PBDEs was systematically evaluated in this study. First, exposure media data on PBDE congeners were compiled. Then, an adult intake dose was derived using exposure factors in combination with these data. The exposure pathways evaluated included food and water ingestion, inhalation, and ingestion and dermal contact to house dust. These intakes were converted to a body burden using a simple pharmacokinetic (PK) model. The predicted body burdens were compared with representative profiles of PBDEs in blood and milk. The adult intake dose of total PBDEs was estimated to be 7.7 ng/kg body weight/day, and children's estimated intakes were higher at 49.3 ng/kg/day for ages 1–5, 14.4 ng/kg/day for 6–11, and 9.1 ng/kg/day for 12–19. The much higher dose for the child age 1–5 was due to the doubling of dust ingestion from 50 to 100 mg/day. The predicted adult body burden of total PBDEs was 33.8 ng/kg lipid weight (lwt), compared to representative measurements in blood and milk at 64.0 and 93.7 ng/g lwt, respectively Most of this apparent underprediction in total concentration was due to an underprediction of the key congener, BDE 47. The value for BDE 47 half-life in the body was identified as the variable most likely in error in this exercise. Other congener predictions compared well with measurements, suggesting general validity with the approach. An important finding from this assessment is that the food intake estimate of about 1.3 ng/kg/day (of the 7.7 ng/kg/day total) cannot explain current US body burdens; exposures to PBDEs in house dust accounted for 82% of the overall estimated intakes.

Degradation of microcystin-LR using sulfate radicals generated through photolysis, thermolysis and e− transfer mechanisms

Abstract: This study explores the potential use of sulfate radical-based advanced oxidation technologies (SR-AOTs) for the degradation of the naturally occurring hepatotoxin, microcystin-LR (MC-LR). The generation of sulfate radicals was achieved by activation of the oxidants persulfate (PS) and peroxymonosulfate (PMS) through electrophilic transition metal cations (Ag+ and Co2+, respectively), radiation (UV 300 − has similar redox potential to hydroxyl radical (HO ), to the best of our knowledge, SR-AOTs have not been tested for the degradation of cyanotoxins. In this study, PMS was activated very efficiently with Co2+ at neutral pH and increasing catalyst concentration resulted in dramatic increase of the initial rates of degradation that reached a plateau for CCo(II) ≥ 1 mg. Based on the optimum pH conditions for each system, the efficiency order is Co2+/PMS > Fe2+/H2O2 ≫ Ag+/PS, which we believe is associated with the energy of the lower unoccupied molecular orbital of the oxidants. When UV (300 Since, the UV lamps used in the study emit light at a range of wavelengths (300

Human Health Risk Assessment (HHRA) for environmental development and transfer of antibiotic resistance.

Abstract: Background: Only recently has the environment been clearly implicated in the risk of antibiotic resistance to clinical outcome, but to date there have been few documented approaches to formally assess these risks. Objective: We examined possible approaches and sought to identify research needs to enable human health risk assessments (HHRA) that focus on the role of the environment in the failure of antibiotic treatment caused by antibiotic-resistant pathogens. Methods: The authors participated in a workshop held 4–8 March 2012 in Quebec, Canada, to define the scope and objectives of an environmental assessment of antibiotic-resistance risks to human health. We focused on key elements of environmental-resistance-development “hot spots,” exposure assessment (unrelated to food), and dose response to characterize risks that may improve antibiotic-resistance management options. Discussion: Various novel aspects to traditional risk assessments were identified to enable an assessment of environmental antibiotic resistance. These include a) accounting for an added selective pressure on the environmental resistome that, over time, allows for development of antibiotic-resistant bacteria (ARB); b) identifying and describing rates of horizontal gene transfer (HGT) in the relevant environmental “hot spot” compartments; and c) modifying traditional dose–response approaches to address doses of ARB for various health outcomes and pathways. Conclusions: We propose that environmental aspects of antibiotic-resistance development be included in the processes of any HHRA addressing ARB. Because of limited available data, a multicriteria decision analysis approach would be a useful way to undertake an HHRA of environmental antibiotic resistance that informs risk managers. Citation: Ashbolt NJ, Amezquita A, Backhaus T, Borriello P, Brandt KK, Collignon P, Coors A, Finley R, Gaze WH, Heberer T, Lawrence JR, Larsson DG, McEwen SA, Ryan JJ, Schonfeld J, Silley P, Snape JR, Van den Eede C, Topp E. 2013. Human health risk assessment (HHRA) for environmental development and transfer of antibiotic resistance. Environ Health Perspect 121:993–1001; http://dx.doi.org/10.1289/ehp.1206316