Environmental Science & Technology | Vol 48, No 11

来自 : 发布时间：2024-05-06

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Get e-AlertsJune 3, 2014Volume 48, Issue 11Pages 6055-6522PREVIOUS ISSUENEXT ISSUEVIEW ALL ISSUESASAPsAbout the Cover:Lake Chapala is one of the largest wintering areas for American white pelicans (Pelecanus erythrorhynchos) in Mexico. Lake Chapala is the ultimate receptor of agreat variety of contaminants, including pesticides and heavy metals, from the Lerma basin and various local sources. American white pelicans are fish-eating birds and can be seriously affected by Hg concentrations in fish. The cover article assesses the potential impacts of Hg on wintering white pelicans in Lake Chapala. View the article.Download CoverIn this issue: Sort By: Viewpoints Improvement of Environmental Remediation by on-Site Phytoremediating GreenhousesCécile Sulmon,Fanny Ramel,Gwenola Gouesbet,andIvan Couée*Environmental Science Technology  2014, 48, 11, 6055-6056 (Viewpoint)Publication Date (Web):May 13, 2014First PageFull textPDFBeyond Safe Operating Space: Finding Chemical Footprinting FeasibleLeo Posthuma*,Anders Bjørn,Michiel C. Zijp,Morten Birkved,Miriam L. Diamond,Michael Z. Hauschild,Mark A. J. Huijbregts,Christian Mulder,andDik Van de MeentEnvironmental Science Technology  2014, 48, 11, 6057-6059 (Viewpoint)Publication Date (Web):May 21, 2014First PageFull textPDF Policy Analysis Life Cycle GHG Emissions from Microalgal Biodiesel – A CA-GREET ModelIan C. Woertz*,John R. Benemann,Niu Du,Stefan Unnasch,Dominick Mendola,B. Greg Mitchell,andTryg J. LundquistEnvironmental Science Technology  2014, 48, 11, 6060-6068 (Policy Analysis)Publication Date (Web):April 29, 2014AbstractFull textPDFABSTRACTA life cycle assessment (LCA) focused on greenhouse gas (GHG) emissions from the production of microalgal biodiesel was carried out based on a detailed engineering and economic analysis. This LCA applies the methodology of the California Low Carbon Fuel Standard (CA LCFS) and uses life cycle inventory (LCI) data for process inputs, based on the California-Modified Greenhouse Gases, Regulated Emissions, and Energy use in Transportation (CA GREET) model. Based on detailed mass and energy balances, calculated GHG emissions from this algal biodiesel system are 70% lower than those of conventional diesel fuel, meeting the minimum 50% GHG reduction requirements under the EPA RFS2 and 60% for the European Union Renewable Energy Directive. This LCA study provides a guide to the research and development objectives that must be achieved to meet both economic and environmental goals for microalgae biodiesel production.Changes in the Carbon Footprint of Japanese Households in an Aging SocietyYosuke Shigetomi*,Keisuke Nansai,Shigemi Kagawa,andSusumu TohnoEnvironmental Science Technology  2014, 48, 11, 6069-6080 (Policy Analysis)Publication Date (Web):May 6, 2014AbstractFull textPDFABSTRACTAs the aging and low birthrate trends continue in Japan, and as changes in the working population and consumption patterns occur, new factors are expected to have an impact on consumption-based greenhouse gas (GHG) emissions. We present the impacts of changes in the composition of Japanese households on GHG emission structures using current (2005) consumption-based accounting on the commodity sectors that are expected to require priority efforts for reducing emissions in 2035. This is done using the Global Link Input-Output model (GLIO) and domestic household consumption data and assuming that recent detailed consumption expenditures based on the Social Accounting Matrix (SAM) will continue into the future. The results show that consumption-based GHG emissions derived from Japanese household consumption in 2035 are estimated to be 1061 Mt-CO2eq (4.2% lower than in 2005). This study can be used to reveal more information and as a resource in developing policies to more meticulously and efficiently reduce emissions based on emission and import rates for each domestic and overseas commodity supply chain. Characterization of Natural and Affected Environments Arsenic in the Multi-aquifer System of the Mekong Delta, Vietnam: Analysis of Large-Scale Spatial Trends and Controlling FactorsLaura E. Erban,Steven M. Gorelick*,andScott FendorfEnvironmental Science Technology  2014, 48, 11, 6081-6088 (Article)Publication Date (Web):May 21, 2014AbstractFull textPDFABSTRACTGroundwater exploitation is rising in the Mekong Delta, Vietnam, potentially exacerbating arsenic contamination from natural sources. We investigate trends and controls on contamination patterns throughout the Delta’s multi-aquifer system as observed in a spatially exhaustive data set of arsenic measured in 40,000 wells, 10.5% of which exceed the WHO drinking water standard for arsenic (10 μg/L). We relate strong trends in the distribution of contamination among well samples to explanatory variables derived from 3D ancillary physicochemical data sets using logistic regression models. Parsimonious models describe much of the observed variability in arsenic occurrence, which differs considerably between subsets of wells tapping shallow versus deeper aquifer groups. In the shallowest Holocene-Pleistocene aquifers, arsenic occurrence is best described by distance to the Mekong river channels and delta front, depth, and location within fault-bounded zones of the region. The same model, however, fails to explain observations in the deeper group of Pliocene-Miocene aquifers. Among these deeper units, arsenic occurrence is rare except among older wells in near-river, heavily pumped areas. Our analysis is the first to examine both natural and anthropogenically mediated contributions to the distribution of arsenic throughout the Mekong Delta’s multi-aquifer system, with implications for management of similarly affected basins throughout Southeast Asia.Common Occurrence of a Positive δ53Cr Shift in Central European Waters Contaminated by Geogenic/Industrial Chromium Relative to Source ValuesMartin Novak*,Vladislav Chrastny,Eva Cadkova,Juraj Farkas,Thomas D. Bullen,Jiri Tylcer,Zdenka Szurmanova,Marcel Cron,Eva Prechova,Jan Curik,Marketa Stepanova,Jan Pasava,Lucie Erbanova,Marie Houskova,Karel Puncochar,andLucas A. HellerichEnvironmental Science Technology  2014, 48, 11, 6089-6096 (Article)Publication Date (Web):April 29, 2014AbstractFull textPDFABSTRACTCarcinogenic effects of hexavalent chromium in waters are of concern in many countries worldwide. We explored Cr isotope systematics at 11 sites in the Czech Republic and Poland. Geogenic Cr pollution was associated with serpentinite bodies at former convergent plate margins, while anthropogenic Cr pollution resulted from electroplating, tanning, and the chemical industry. Cr(VI) concentration in geogenic waters was less than 40 ppb. Anthropogenic waters contained up to 127,000 ppb Cr(VI). At both geogenic and anthropogenic sites, where known, the source of pollution had a low δ53Cr ( 1‰). δ53Cr of geogenic and anthropogenic waters was up to 3.9 and 5.8‰, respectively. At both serpentinite-dominated and industrial sites, δ53Cr(VI)aq was shifted toward higher values, compared to the pollution source. At the industrial sites, this positive δ53Cr shift was related to Cr(VI) reduction, a process known to fractionate Cr isotopes. At geogenic sites, the origin of high δ53Cr(VI)aq is tentatively ascribed to preferential release of 53Cr during oxidation of soil Cr(III) and its mobilization to water. δ53Cr(VI) of industrially contaminated waters was significantly higher (p 0.001) compared to δ53Cr of waters carrying geogenic Cr(VI), implying that either the effective fractionation factor or process extent was greater for Cr(VI) reduction than for Cr(III) oxidation.Influence of Phosphate and Silica on U(VI) Precipitation from Acidic and Neutralized WastewatersMasakazu Kanematsu*,Nicolas Perdrial,Wooyong Um,Jon Chorover,andPeggy A. O’DayEnvironmental Science Technology  2014, 48, 11, 6097-6106 (Article)Publication Date (Web):April 22, 2014AbstractFull textPDFABSTRACTUranium speciation and physical–chemical characteristics were studied in solids precipitated from synthetic acidic to circumneutral wastewaters in the presence and absence of dissolved silica and phosphate to examine thermodynamic and kinetic controls on phase formation. Composition of synthetic wastewater was based on disposal sites 216-U-8 and 216-U-12 Cribs at the Hanford site (WA, USA). In the absence of dissolved silica or phosphate, crystalline or amorphous uranyl oxide hydrates, either compreignacite or meta-schoepite, precipitated at pH 5 or 7 after 30 d of reaction, in agreement with thermodynamic calculations. In the presence of 1 mM dissolved silica representative of groundwater concentrations, amorphous phases dominated by compreignacite precipitated rapidly at pH 5 or 7 as a metastable phase and formation of poorly crystalline boltwoodite, the thermodynamically stable uranyl silicate phase, was slow. In the presence of phosphate (3 mM), meta-ankoleite initially precipitated as the primary phase at pH 3, 5, or 7 regardless of the presence of 1 mM dissolved silica. Analysis of precipitates by U LIII-edge extended X-ray absorption fine structure (EXAFS) indicated that \"autunite-type” sheets of meta-ankoleite transformed to \"phosphuranylite-type” sheets after 30 d of reaction, probably due to Ca substitution in the structure. Low solubility of uranyl phosphate phases limits dissolved U(VI) concentrations but differences in particle size, crystallinity, and precipitate composition vary with pH and base cation concentration, which will influence the thermodynamic and kinetic stability of these phases.A Fluvial Mercury Budget for Lake OntarioJoseph S. Denkenberger*,Charles T. Driscoll,Edward Mason,Brian Branfireun,andAshley WarnockEnvironmental Science Technology  2014, 48, 11, 6107-6114 (Article)Publication Date (Web):May 1, 2014AbstractFull textPDFABSTRACTWatershed mercury (Hg) flux was calculated for ten inflowing rivers and the outlet for Lake Ontario using empirical measurements from two independent field-sampling programs. Total Hg (THg) flux for nine study watersheds that directly drain into the lake ranged from 0.2 kg/yr to 13 kg/yr, with the dominant fluvial THg load from the Niagara River at 154 kg/yr. THg loss at the outlet (St. Lawrence River) was 68 kg/yr and has declined approximately 40% over the past decade. Fluvial Hg inputs largely (62%) occur in the dissolved fraction and are similar to estimates of atmospheric Hg inputs. Fluvial mass balances suggest strong in-lake retention of particulate Hg inputs (99%), compared to dissolved total Hg (45%) and methyl Hg (22%) fractions. Wetland land cover is a good predictor of methyl Hg yield for Lake Ontario watersheds. Sediment deposition studies, coupled atmospheric and fluvial Hg fluxes, and a comparison of this work with previous measurements indicate that Lake Ontario is a net sink of Hg inputs and not at steady state likely because of recent decreases in point source inputs and atmospheric Hg deposition.Lacustrine Responses to Decreasing Wet Mercury Deposition Rates—Results from a Case Study in Northern MinnesotaMark E. Brigham*,Mark B. Sandheinrich,David A. Gay,Ryan P. Maki,David P. Krabbenhoft,andJames G. WienerEnvironmental Science Technology  2014, 48, 11, 6115-6123 (Article)ACS AuthorChoicePublication Date (Web):May 16, 2014ACS AuthorChoiceAbstractFull textPDFABSTRACTWe present a case study comparing metrics of methylmercury (MeHg) contamination for four undeveloped lakes in Voyageurs National Park to wet atmospheric deposition of mercury (Hg), sulfate (SO4–2), and hydrogen ion (H+) in northern Minnesota. Annual wet Hg, SO4–2, and H+ deposition rates at two nearby precipitation monitoring sites indicate considerable decreases from 1998 to 2012 (mean decreases of 32, 48, and 66%, respectively). Consistent with decreases in the atmospheric pollutants, epilimnetic aqueous methylmercury (MeHgaq) and mercury in small yellow perch (Hgfish) decreased in two of four lakes (mean decreases of 46.5% and 34.5%, respectively, between 2001 and 2012). Counter to decreases in the atmospheric pollutants, MeHgaq increased by 85% in a third lake, whereas Hgfish increased by 80%. The fourth lake had two disturbances in its watershed during the study period (forest fire; changes in shoreline inundation due to beaver activity); this lake lacked overall trends in MeHgaq and Hgfish. The diverging responses among the study lakes exemplify the complexity of ecosystem responses to decreased loads of atmospheric pollutants.Air–Water Exchange of Brominated Anisoles in the Northern Baltic SeaTerry F. Bidleman*,Kathleen Agosta,Agneta Andersson,Peter Haglund,Olle Nygren,Matyas Ripszam,andMats TysklindEnvironmental Science Technology  2014, 48, 11, 6124-6132 (Article)ACS AuthorChoicePublication Date (Web):May 8, 2014ACS AuthorChoiceAbstractFull textPDFABSTRACTBromophenols produced by marine algae undergo O-methylation to form bromoanisoles (BAs), which are exchanged between water and air. BAs were determined in surface water of the northern Baltic Sea (Gulf of Bothnia, consisting of Bothnian Bay and Bothnian Sea) during 2011–2013 and on a transect of the entire Baltic in September 2013. The abundance decreased in the following order: 2,4,6-tribromoanisole (2,4,6-TBA) 2,4-dibromoanisole (2,4-DBA) ≫ 2,6-dibromoanisole (2,6-DBA). Concentrations of 2,4-DBA and 2,4,6-TBA in September were higher in the southern than in the northern Baltic and correlated well with the higher salinity in the south. This suggests south-to-north advection and dilution with fresh riverine water enroute, and/or lower production in the north. The abundance in air over the northern Baltic also decreased in the following order: 2,4,6-TBA 2,4-DBA. However, 2,6-DBA was estimated as a lower limit due to breakthrough from polyurethane foam traps used for sampling. Water/air fugacity ratios ranged from 3.4 to 7.6 for 2,4-DBA and from 18 to 94 for 2,4,6-TBA, indicating net volatilization. Flux estimates using the two-film model suggested that volatilization removes 980–1360 kg of total BAs from Bothnian Bay (38000 km2) between May and September. The release of bromine from outgassing of BAs could be up to 4–6% of bromine fluxes from previously reported volatilization of bromomethanes and bromochloromethanes.Organophosphate and Halogenated Flame Retardants in Atmospheric Particles from a European Arctic SiteAmina Salamova,Mark H. Hermanson,andRonald A. Hites*Environmental Science Technology  2014, 48, 11, 6133-6140 (Article)Publication Date (Web):May 21, 2014AbstractFull textPDFABSTRACTLevels of 13 organophosphate esters (OPEs) and 45 brominated and chlorinated flame retardants (BFRs) were measured in particle phase atmospheric samples collected at Longyearbyen on Svalbard in the European Arctic from September 2012 to May 2013. Total OPE (ΣOPEs) concentrations ranged from 33 to 1450 pg/m3, with the mean ΣOPE concentration of 430 ± 57 pg/m3. The nonchlorinated tri-n-butyl phosphate (TnBP) and 2-ethylhexyl-diphenyl phosphate (EHDPP) were the most abundant OPE congeners measured, and the sum of all nonchlorinated OPE concentrations comprised ∼75% of the ΣOPE concentrations. The most abundant chlorinated OPE was tris(1-chloro-2-propyl) phosphate (TCPP). Total BFR concentrations (ΣBFRs) were in the range of 3–77 pg/m3, with a mean concentration of 15 ± 3 pg/m3. 2-Ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB) and bis(2-ethylhexyl)tetrabromophthalate (TBPH) were among the relatively abundant BFRs measured in these samples and comprised ∼46% and 17% of ΣBFR concentrations, respectively. Total PBDE (ΣPBDE) concentrations constituted ∼37% of ΣBFR concentrations on average and ranged from 1 to 31 pg/m3. The most abundant PBDE congener was BDE-209, which contributed 24% to ΣPBDE concentrations. Dechlorane Plus (DP) was detected in all of the samples, and ΣDP concentrations (syn- + anti-DP concentrations) ranged from 0.05 to 5 pg/m3. Overall, ΣOPE concentrations were 1–2 orders of magnitude higher than the ΣBFR concentrations. Environmental Processes Diffusive Fractionation of BTEX and Chlorinated Ethenes in Aqueous Solution: Quantification of Spatial Isotope GradientsBiao Jin,Massimo Rolle*,Ting Li,andStefan B. HaderleinEnvironmental Science Technology  2014, 48, 11, 6141-6150 (Article)Publication Date (Web):May 8, 2014AbstractFull textPDFABSTRACTLaboratory experiments were performed to investigate and quantify the extent of diffusive isotope fractionation of organic contaminants in aqueous solution. We selected petroleum hydrocarbons (toluene and ethylbenzene, in 1:2 mixtures of labeled (perdeuterated) and nonlabeled isotopologues) and chlorinated solvents (trichloroethene, TCE, and cis-dichloroethene, cis-DCE, at their natural isotopic abundance) as model compounds. The experimental approach using gel diffusion tubes allowed us to resolve concentration and isotopic gradients induced by isotopologue-specific diffusion and to determine aqueous diffusion coefficients in agreement with the values calculated using published empirical correlations. The experimental results were quantitatively evaluated with numerical simulations to determine the aqueous diffusion coefficients, D, and the exponent of the inverse power-law relation between D and the molecular mass of the isotopologues. The results show remarkable diffusive isotope fractionation for all the investigated organic compounds; however, the extent of fractionation was found to be smaller for the chlorinated ethenes and remarkably deviating from an inverse square root relationship between the isotopologues diffusion coefficients and their molecular mass. The outcomes of this study are relevant for the interpretation of isotopic signatures of organic contaminants in environmental systems and for the quantitative application of compound specific isotope analysis (CSIA) that needs to take into account the fractionation effects of both physical and transformation processes.Origin and Sources of Dissolved Organic Matter in Snow on the East Antarctic Ice SheetRuna Antony,Amanda M. Grannas,Amanda S. Willoughby,Rachel L. Sleighter,Meloth Thamban,andPatrick G. HatcherEnvironmental Science Technology  2014, 48, 11, 6151-6159 (Article)Publication Date (Web):May 7, 2014AbstractFull textPDFABSTRACTPolar ice sheets hold a significant pool of the world’s carbon reserve and are an integral component of the global carbon cycle. Yet, organic carbon composition and cycling in these systems is least understood. Here, we use ultrahigh resolution mass spectrometry to elucidate, at an unprecedented level, molecular details of dissolved organic matter (DOM) in Antarctic snow. Tens of thousands of distinct molecular species are identified, providing clues to the nature and sources of organic carbon in Antarctica. We show that many of the identified supraglacial organic matter formulas are consistent with material from microbial sources, and terrestrial inputs of vascular plant-derived materials are likely more important sources of organic carbon to Antarctica than previously thought. Black carbon-like material apparently originating from biomass burning in South America is also present, while a smaller fraction originated from soil humics and appears to be photochemically or microbially modified. In addition to remote continental sources, we document signals of oceanic emissions of primary aerosols and secondary organic aerosol precursors. The new insights on the diversity of organic species in Antarctic snowpack reinforce the importance of studying organic carbon associated with the Earth’s polar regions in the face of changing climate.Influence of Bioselector Processes on 17α-Ethinylestradiol Biodegradation in Activated Sludge Wastewater Treatment SystemsRyan M. Ziels,Mariko J. Lust,Heidi L. Gough,Stuart E. Strand,andH. David Stensel*Environmental Science Technology  2014, 48, 11, 6160-6167 (Article)Publication Date (Web):May 8, 2014AbstractFull textPDFABSTRACTThe removal of the potent endocrine-disrupting estrogen hormone, 17α-ethinylestradiol (EE2), in municipal wastewater treatment plant (WWTP) activated sludge (AS) processes can occur through biodegradation by heterotrophic bacteria growing on other organic wastewater substrates. Different kinetic and metabolic substrate utilization conditions created with AS bioselector processes can affect the heterotrophic population composition in AS. The primary goal of this research was to determine if these changes also affect specific EE2 biodegradation kinetics. A series of experiments were conducted with parallel bench-scale AS reactors treating municipal wastewater with estrogens at 100–300 ng/L concentrations to evaluate the effect of bioselector designs on pseudo first-order EE2 biodegradation kinetics normalized to mixed liquor volatile suspended solids (VSS). Kinetic rate coefficient (kb) values for EE2 biodegradation ranged from 5.0 to 18.9 L/g VSS/d at temperatures of 18 °C to 24 °C. EE2 kb values for aerobic biomass growth at low initial food to mass ratio feeding conditions (F/Mf) were 1.4 to 2.2 times greater than that from growth at high initial F/Mf. Anoxic/aerobic and anaerobic/aerobic metabolic bioselector reactors achieving biological nutrient removal had similar EE2 kb values, which were lower than that in aerobic AS reactors with biomass growth at low initial F/Mf. These results provide evidence that population selection with growth at low organic substrate concentrations can lead to improved EE2 biodegradation kinetics in AS treatment.Parameterization of Thermal Properties of Aging Secondary Organic Aerosol Produced by Photo-Oxidation of Selected Terpene MixturesEva U. Emanuelsson,Thomas F. Mentel,Ågot K. Watne,Christian Spindler,Birger Bohn,Theo Brauers,Hans-Peter Dorn,Åsa M. Hallquist,Rolf Häseler,Astrid Kiendler-Scharr,Klaus-Peter Müller,Håkan Pleijel,Franz Rohrer,Florian Rubach,Eric Schlosser,Ralf Tillmann,andMattias Hallquist*Environmental Science Technology  2014, 48, 11, 6168-6176 (Article)Publication Date (Web):May 8, 2014AbstractFull textPDFABSTRACTFormation and evolution of secondary organic aerosols (SOA) from biogenic VOCs influences the Earth’s radiative balance. We have examined the photo-oxidation and aging of boreal terpene mixtures in the SAPHIR simulation chamber. Changes in thermal properties and chemical composition, deduced from mass spectrometric measurements, were providing information on the aging of biogenic SOA produced under ambient solar conditions. Effects of precursor mixture, concentration, and photochemical oxidation levels (OH exposure) were evaluated. OH exposure was found to be the major driver in the long term photochemical transformations, i.e., reaction times of several hours up to days, of SOA and its thermal properties, whereas the initial concentrations and terpenoid mixtures had only minor influence. The volatility distributions were parametrized using a sigmoidal function to determine TVFR0.5 (the temperature yielding a 50% particle volume fraction remaining) and the steepness of the volatility distribution. TVFR0.5 increased by 0.3 ± 0.1% (ca. 1 K), while the steepness increased by 0.9 ± 0.3% per hour of 1 × 106 cm–3 OH exposure. Thus, aging reduces volatility and increases homogeneity of the vapor pressure distribution, presumably because highly volatile fractions become increasingly susceptible to gas phase oxidation, while less volatile fractions are less reactive with gas phase OH.Pore-Size-Dependent Calcium Carbonate Precipitation Controlled by Surface ChemistryAndrew G. Stack*,Alejandro Fernandez-Martinez,Lawrence F. Allard,José L. Bañuelos,Gernot Rother,Lawrence M. Anovitz,David R. Cole,andGlenn A. WaychunasEnvironmental Science Technology  2014, 48, 11, 6177-6183 (Article)Publication Date (Web):May 9, 2014AbstractFull textPDFABSTRACTInduced mineral precipitation is potentially important for the remediation of contaminants, such as during mineral trapping during carbon or toxic metal sequestration. The prediction of precipitation reactions is complicated by the porous nature of rocks and soils and their interaction with the precipitate, introducing transport and confinement effects. Here X-ray scattering measurements, modeling, and electron microscopies were used to measure the kinetics of calcium carbonate precipitation in a porous amorphous silica (CPG) that contained two discrete distributions of pore sizes: nanopores and macropores. To examine the role of the favorability of interaction between the substrate and precipitate, some of the CPG was functionalized with a self-assembled monolayer (SAM) similar to those known to enhance nucleation densities on planar substrates. Precipitation was found to occur exclusively in macropores in the native CPG, while simultaneous precipitation in nanopores and macropores was observed in the functionalized CPG. The rate of precipitation in the nanopores estimated from the model of the X-ray scattering matched that measured on calcite single crystals. These results suggest that the pore-size distribution in which a precipitation reaction preferentially occurs depends on the favorability of interaction between substrate and precipitate, something not considered in most studies of precipitation in porous media.In Vitro Metabolic Formation of Perfluoroalkyl Sulfonamides from Copolymer Surfactants of Pre- and Post-2002 Scotchgard Fabric Protector ProductsShaogang ChuandRobert J. Letcher*Environmental Science Technology  2014, 48, 11, 6184-6191 (Article)Publication Date (Web):May 1, 2014AbstractFull textPDFABSTRACTCurrently there is a scientific debate on whether fluorinated polymers (or copolymers) are a source, as a result of their degradation and subsequent formation, of perfluorinated carboxylic acids (PFCAs) and perfluorinated alkanesulfonates (PFSAs). The present study investigated whether commercially available fluorinated surfactants, such as Scotchgard fabric protector (3M Company), can be metabolically degraded, using a model microsomal in vitro assay (Wistar-Han rats liver microsomes), and with concomitant formation of PFCAs, PFASs, and/or their precursors. The results showed that the main in vitro metabolite from the pre-2002 product was perfluorooctane sulfonamide (FOSA), and coincident with the detection of the major fabric protector components, which contains the N-ethyl-perfluorooctanesulfonyl chemical moiety (C8F17SO2N(C2H5)−); the main in vitro metabolite of the post-2002 product was perfluorobutane sulfonamide (FBSA), which was coincident with the detection of the major fabric protector components, and contains the N-methyl-perfluorobutanesulfonyl chemical moiety (C4F9SO2N(CH3)−). FOSA or FBSA metabolite concentrations increased over the 0–60 min microsomal incubation period. However, concentrations of their small molecule precursors such as alkylated FOSAs or FBSAs were not detectable ( LODs) in these fabric protector original standard solutions. Thus, the FOSA or FBSA metabolites were derived from the copolymer product itself rather than nonreacted reagents in the Scotchgard products. This result is consistent with reports of high concentrations of PFASs detected in the plasma of persons in households where Scotchgard products are heavily used.Rock Glacier Outflows May Adversely Affect Lakes: Lessons from the Past and Present of Two Neighboring Water Bodies in a Crystalline-Rock WatershedBoris P. Ilyashuk*,Elena A. Ilyashuk,Roland Psenner,Richard Tessadri,andKarin A. KoinigEnvironmental Science Technology  2014, 48, 11, 6192-6200 (Article)ACS AuthorChoicePublication Date (Web):May 7, 2014ACS AuthorChoiceAbstractFull textPDFABSTRACTDespite the fact that rock glaciers are one of the most common geomorphological expressions of mountain permafrost, the impacts of their solute fluxes on lakes still remain largely obscure. We examined water and sediment chemistry, and biota of two neighboring water bodies with and without a rock glacier in their catchments in the European Alps. Paleolimnological techniques were applied to track long-term temporal trends in the ecotoxicological state of the water bodies and to establish their baseline conditions. We show that the active rock glacier in the mineralized catchment of Lake Rasass (RAS) represents a potent source of acid rock drainage that results in enormous concentrations of metals in water, sediment, and biota of RAS. The incidence of morphological abnormalities in the RAS population of Pseudodiamesa nivosa, a chironomid midge, is as high as that recorded in chironomid populations inhabiting sites heavily contaminated by trace metals of anthropogenic origin. The incidence of morphological deformities in P. nivosa of ∼70% persisted in RAS during the last 2.5 millennia and was ∼40% in the early Holocene. The formation of RAS at the toe of the rock glacier most probably began at the onset of acidic drainage in the freshly deglaciated area. The present adverse conditions are not unprecedented in the lake’s history and cannot be associated exclusively with enhanced thawing of the rock glacier in recent years.Plutonium Desorption from Mineral Surfaces at Environmental Concentrations of Hydrogen PeroxideJames D. Begg*,Mavrik Zavarin,andAnnie B. KerstingEnvironmental Science Technology  2014, 48, 11, 6201-6210 (Article)Publication Date (Web):May 9, 2014AbstractFull textPDFABSTRACTKnowledge of Pu adsorption and desorption behavior on mineral surfaces is crucial for understanding its environmental mobility. Here we demonstrate that environmental concentrations of H2O2 can affect the stability of Pu adsorbed to goethite, montmorillonite, and quartz across a wide range of pH values. In batch experiments where Pu(IV) was adsorbed to goethite for 21 days at pH 4, 6, and 8, the addition of 5–500 μM H2O2 resulted in significant Pu desorption. At pH 6 and 8 this desorption was transient with readsorption of the Pu to goethite within 30 days. At pH 4, no Pu readsorption was observed. Experiments with both quartz and montmorillonite at 5 μM H2O2 desorbed far less Pu than in the goethite experiments highlighting the contribution of Fe redox couples in controlling Pu desorption at low H2O2 concentrations. Plutonium(IV) adsorbed to quartz and subsequently spiked with 500 μM H2O2 resulted in significant desorption of Pu, demonstrating the complexity of the desorption process. Our results provide the first evidence of H2O2-driven desorption of Pu(IV) from mineral surfaces. We suggest that this reaction pathway coupled with environmental levels of hydrogen peroxide may contribute to Pu mobility in the environment.Sources and Transport of Nitrogen in Arid Urban WatershedsRebecca L. Hale*,Laura Turnbull,Stevan Earl,Nancy Grimm,Krystin Riha,Greg Michalski,Kathleen A. Lohse,andDaniel ChildersEnvironmental Science Technology  2014, 48, 11, 6211-6219 (Article)Publication Date (Web):May 6, 2014AbstractFull textPDFABSTRACTUrban watersheds are often sources of nitrogen (N) to downstream systems, contributing to poor water quality. However, it is unknown which components (e.g., land cover and stormwater infrastructure type) of urban watersheds contribute to N export and which may be sites of retention. In this study we investigated which watershed characteristics control N sourcing, biogeochemical processing of nitrate (NO3–) during storms, and the amount of rainfall N that is retained within urban watersheds. We used triple isotopes of NO3– (δ15N, δ18O, and Δ17O) to identify sources and transformations of NO3– during storms from 10 nested arid urban watersheds that varied in stormwater infrastructure type and drainage area. Stormwater infrastructure and land cover—retention basins, pipes, and grass cover—dictated the sourcing of NO3– in runoff. Urban watersheds were strong sinks or sources of N to stormwater depending on runoff, which in turn was inversely related to retention basin density and positively related to imperviousness and precipitation. Our results suggest that watershed characteristics control the sources and transport of inorganic N in urban stormwater but that retention of inorganic N at the time scale of individual runoff events is controlled by hydrologic, rather than biogeochemical, mechanisms. Environmental Modeling Combined Source Apportionment and Degradation Quantification of Organic Pollutants with CSIA: 1. Model DerivationS. R. Lutz*andB. M. Van BreukelenEnvironmental Science Technology  2014, 48, 11, 6220-6228 (Article)Publication Date (Web):May 7, 2014AbstractFull textPDFABSTRACTCompound-specific stable isotope analysis (CSIA) serves as a tool for source apportionment (SA) and for the quantification of the extent of degradation (QED) of organic pollutants. However, simultaneous occurrence of mixing of sources and degradation is generally believed to hamper both SA and QED. On the basis of the linear stable isotope mixing model and the Rayleigh equation, we developed the stable isotope sources and sinks model, which allows for simultaneous SA and QED of a pollutant that is emitted by two sources and degrades via one transformation process. It was shown that the model necessitates at least dual-element CSIA for unequivocal SA in the presence of degradation-induced isotope fractionation, as illustrated for perchlorate in groundwater. The model also enables QED, provided degradation follows instantaneous mixing of two sources. If mixing occurs after two sources have degraded separately, the model can still provide a conservative estimate of the overall extent of degradation. The model can be extended to a larger number of sources and sinks as outlined. It may aid in forensics and natural attenuation assessment of soil, groundwater, surface water, or atmospheric pollution.Combined Source Apportionment and Degradation Quantification of Organic Pollutants with CSIA: 2. Model Validation and ApplicationS. R. LutzandB. M. Van BreukelenEnvironmental Science Technology  2014, 48, 11, 6229-6236 (Article)Publication Date (Web):May 7, 2014AbstractFull textPDFABSTRACTCompound-specific stable isotope analysis (CSIA) has proven a useful tool for the quantification of the extent of degradation (QED), and for source identification and source apportionment (SA) in contaminated environmental systems. However, the simultaneous occurrence of degradation processes and mixing of emission sources complicates the use of CSIA in combined SA and QED. In a companion study, we developed a mathematical model that allows for combined SA and QED of organic pollutants (and inorganic compounds such as nitrate) in a scenario of two emission sources and degradation via one reaction pathway. This work presents a validation of the model against virtual data from a two-dimensional reactive transport model. The model calculations for SA and QED were in good agreement with the simulation results, which suggests the correctness of the model assumptions. However, the application of the model to field data of benzene contamination was challenged by large uncertainties in CSIA data and the unknown interplay between competing degradation pathways. Nonetheless, the use of the model allowed for the identification of a prevailing contribution of one emission source and revealed a low overall extent of degradation at the field site. This indicates that the model can, for example, facilitate the characterization of air pollution or aquifer contamination with organic pollutants.Role of Management Strategies and Environmental Factors in Determining the Emissions of Biogenic Volatile Organic Compounds from Urban GreenspacesYuan Ren,Ying Ge,Baojing Gu,Yong Min,Akira Tani,andJie Chang*Environmental Science Technology  2014, 48, 11, 6237-6246 (Article)Publication Date (Web):May 8, 2014AbstractFull textPDFABSTRACTBiogenic volatile organic compound (BVOC) emissions from urban greenspace have recently become a global concern. To identify key factors affecting the dynamics of urban BVOC emissions, we built an estimation model and utilized the city of Hangzhou in southeastern China as an example. A series of single-factor scenarios were first developed, and then nine multifactor scenarios using a combination of different single-factor scenarios were built to quantify the effects of environmental changes and urban management strategies on urban BVOC emissions. Results of our model simulations showed that (1) annual total BVOC emissions from the metropolitan area of Hangzhou were 4.7 × 108 g of C in 2010 and were predicted to be 1.2–3.2 Gg of C (1 Gg = 109 g) in our various scenarios in 2050, (2) urban management played a more important role in determining future urban BVOC emissions than environmental changes, and (3) a high ecosystem service value (e.g., lowest BVOC/leaf mass ratio) could be achieved through positive coping in confronting environmental changes and adopting proactive urban management strategies on a local scale, that is, to moderately increase tree density while restricting excessive greenspace expansion and optimizing the species composition of existing and newly planted trees.Spatial Stochastic Modeling of Sedimentary Formations to Assess CO2 Storage PotentialOlga H. Popova*,Mitchell J. Small,Sean T. McCoy,A. C. Thomas,Stephen Rose,Bobak Karimi,Kristin Carter,andAngela GoodmanEnvironmental Science Technology  2014, 48, 11, 6247-6255 (Article)Publication Date (Web):May 13, 2014AbstractFull textPDFABSTRACTCarbon capture and sequestration (CCS) is a technology that provides a near-term solution to reduce anthropogenic CO2 emissions to the atmosphere and reduce our impact on the climate system. Assessments of carbon sequestration resources that have been made for North America using existing methodologies likely underestimate uncertainty and variability in the reservoir parameters. This paper describes a geostatistical model developed to estimate the CO2 storage resource in sedimentary formations. The proposed stochastic model accounts for the spatial distribution of reservoir properties and is implemented in a case study of the Oriskany Formation of the Appalachian sedimentary basin. Results indicate that the CO2 storage resource for the Pennsylvania part of the Oriskany Formation has substantial spatial variation due to heterogeneity of formation properties and basin geology leading to significant uncertainty in the storage assessment. The Oriskany Formation sequestration resource estimate in Pennsylvania calculated with the effective efficiency factor, E = 5%, ranges from 0.15 to 1.01 gigatonnes (Gt) with a mean value of 0.52 Gt of CO2 (E = 5%). The methodology is generalizable to other sedimentary formations in which site-specific trend analyses and statistical models are developed to estimate the CO2 sequestration storage capacity and its uncertainty. More precise CO2 storage resource estimates will provide better recommendations for government and industry leaders and inform their decisions on which greenhouse gas mitigation measures are best fit for their regions. Environmental Measurements Methods Evaluation of Mercury Stress in Plants from the Almadén Mining District by Analysis of Phytochelatins and Their Hg ComplexesÀngela Dago,Inmaculada González,Cristina Ariño*,Alba Martínez-Coronado,Pablo Higueras,José Manuel Díaz-Cruz,andMiquel EstebanEnvironmental Science Technology  2014, 48, 11, 6256-6263 (Article)Publication Date (Web):May 2, 2014AbstractFull textPDFABSTRACTTo evaluate plant response to Hg stress, glutathione, phytochelatins, and their Hg complexes were analyzed using HPLC with amperometric detection in samples of Asparagus acutifolius grown in the Almadén mining district (Ciudad Real, Spain), one of the most Hg-contaminated sites in the world. Soils of the Almadén mining district, and specifically from the Almadenejos zone, are highly contaminated, with some zones having values above 4,000 μg Hg g–1 soil. Although soils have an extremely high concentration of mercury, generally less than 2% is available for plants, as is shown by various soil extractions simulating bioavailability. In plants, Hg concentration increases depending on the content of Hg in soils. In addition, Hg levels in roots are higher than in aerial parts, which is a strategy of plants for protecting their more sensitive aerial parts from the deleterious effects of metal stress. The total content of phytochelatins (PCs) and their complexes are directly related with the amount of mercury in soils. These findings highlight the important role of thiol compounds and their metal complexes in capturing and fixing Hg from soils, giving plants the capacity to deal with the heavy metal toxicity of polluted soils.Monitoring Arsenic Contamination in Agricultural Soils with Reflectance Spectroscopy of Rice PlantsTiezhu Shi,Huizeng Liu,Junjie Wang,Yiyun Chen,Teng Fei,andGuofeng WuEnvironmental Science Technology  2014, 48, 11, 6264-6272 (Article)Publication Date (Web):May 7, 2014AbstractFull textPDFABSTRACTThe objective of this study was to explore the feasibility and to investigate the mechanism for rapidly monitoring arsenic (As) contamination in agricultural soils with the reflectance spectra of rice plants. Several data pretreatment methods were applied to improve the prediction accuracy. The prediction of soil As contents was achieved by partial least-squares regression (PLSR) using laboratory and field spectra of rice plants, as well as linear regression employing normalized difference spectral index (NDSI) calculated from fild spectra. For laboratory spectra, the optimal PLSR model for predicting soil As contents was achieved using Savitzky-Golay smoothing (SG), first derivative and mean center (MC) (root-mean-square error of prediction (RMSEP) = 14.7 mg kg–1; r = 0.64; residual predictive deviation (RPD) = 1.31). For field spectra, the optimal PLSR model was also achieved using SG, first derivative and MC (RMSEP = 13.7 mg kg–1; r = 0.71; RPD = 1.43). In addition, the NDSI with 812 and 782 nm obtained a prediction accuracy with r = 0.68, RMSEP = 13.7 mg kg–1, and RPD = 1.36. These results indicated that it was feasible to monitor the As contamination in agricultural soils using the reflectance spectra of rice plants. The prediction mechanism might be the relationship between the As contents in soils and the chlorophyll-a/-b contents and cell structure in leaves or canopies of rice plants.Transboundary Secondary Organic Aerosol in Western Japan Indicated by the δ13C of Water-Soluble Organic Carbon and the m/z 44 Signal in Organic Aerosol Mass SpectraSatoshi Irei*,Akinori Takami,Masahiko Hayashi,Yasuhiro Sadanaga,Keiichiro Hara,Naoki Kaneyasu,Kei Sato,Takemitsu Arakaki,Shiro Hatakeyama,Hiroshi Bandow,Toshihide Hikida,andAkio ShimonoEnvironmental Science Technology  2014, 48, 11, 6273-6281 (Article)ACS AuthorChoicePublication Date (Web):May 7, 2014ACS AuthorChoiceAbstractFull textPDFABSTRACTThe stable carbon isotope ratio (δ13C) of low-volatile water-soluble organic carbon (LV-WSOC) was measured in filter samples of total suspended particulate matter, collected every 24 h in the winter of 2010 at an urban site and two rural sites in western Japan. Concentrations of the major chemical species in fine aerosol ( 1.0 μm) were also measured in real time by aerosol mass spectrometers. The oxidation state of organic aerosol was evaluated using f44; i.e., the proportion of the signal at m/z 44 (CO2+ ions from the carboxyl group) to the sum of all m/z signals in the organic mass spectra. A strong correlation between LV-WSOC and m/z 44 concentrations was observed, which suggested that LV-WSOC was likely to be associated with carboxylic acids in fine aerosol. Plots of δ13C of LV-WSOC versus f44 showed random variation at the urban site and systematic trends at the rural sites. The systematic trends qualitatively agreed with a simple binary mixture model of secondary organic aerosol with background LV-WSOC with an f44 of ∼0.08 and δ13C of −17‰ or higher. Comparison with reference values suggested that the source of background LV-WSOC was likely to be primary emissions associated with C4 plants.Automatic Kinetic Bioaccessibility Assay of Lead in Soil Environments Using Flow-through Microdialysis as a Front End to Electrothermal Atomic Absorption SpectrometryDavid J. Cocovi-Solberg,Maria Rosende,andManuel Miró*Environmental Science Technology  2014, 48, 11, 6282-6290 (Article)Publication Date (Web):May 2, 2014AbstractFull textPDFABSTRACTIn-line microdialysis is in this work hyphenated to electrothermal atomic absorption spectrometry via a dedicated flow-based interface for monitoring the batchwise leaching test endorsed by the Standards, Measurements and Testing Program (SM T) of the European Commission. The bioaccessible pool of lead in soils is measured using 0.43 mol/L AcOH as extractant. The proposed method allows to gain knowledge of leaching kinetics at real-time, simplify the overall procedure by accurate detection of steady-state conditions and overcome sample filtration or centrifugation. Soil leachates were automatically sampled at specified timeframes (e.g, every 20 or 80 min), processed in an external container (where dilution can be applied at will) and further injected into the atomizer. The method was experimentally validated by comparison of in situ microdialysis sampling results with in-line microfiltration in two soils of varying physicochemical properties. A mathematical framework was used for discrimination of different metal fractions (that is, readily mobilizable against slowly mobilizable lead) and also for estimating the total extractable lead under actual steady-state conditions. We have demonstrated that bioaccessibility tests lasting 16 h as endorsed by SM T might not suffice for ascertainment of maximum (steady-state) bioaccessibility of lead in terrestrial environments as demanded in risk assessment programs.Predicting Polycyclic Aromatic Hydrocarbon Concentrations in Resident Aquatic Organisms Using Passive Samplers and Partial Least-Squares CalibrationNorman D. Forsberg,Brian W. Smith,Greg J. Sower,andKim A. Anderson*Environmental Science Technology  2014, 48, 11, 6291-6299 (Article)ACS AuthorChoicePublication Date (Web):May 7, 2014ACS AuthorChoiceAbstractFull textPDFABSTRACTThe current work sought to develop predictive models between time-weighted average polycyclic aromatic hydrocarbon (PAH) concentrations in the freely dissolved phase and those present in resident aquatic organisms. We deployed semipermeable membrane passive sampling devices (SPMDs) and collected resident crayfish (Pacifastacus leniusculus) at nine locations within and outside of the Portland Harbor Superfund Mega-site in Portland, OR. Study results show that crayfish and aqueous phase samples collected within the Mega-site had PAH profiles enriched in high molecular weight PAHs and that freely dissolved PAH profiles tended to be more populated by low molecular weight PAHs compared to crayfish tissues. Results also show that of several modeling approaches, a two-factor partial least-squares (PLS) calibration model using detection limit substitution provided the best predictive power for estimating PAH concentrations in crayfish, where the model explained ≥72% of the variation in the data set and provided predictions within ∼3× of measured values. Importantly, PLS calibration provided a means to estimate PAH concentrations in tissues when concentrations were below detection in the freely dissolved phase. The impact of measurements below detection limits is discussed.Effective Density and Mixing State of Aerosol Particles in a Near-Traffic Urban EnvironmentJenny Rissler*,Erik Z. Nordin,Axel C. Eriksson,Patrik T. Nilsson,Mia Frosch,Moa K. Sporre,Aneta Wierzbicka,Birgitta Svenningsson,Jakob Löndahl,Maria E. Messing,Staffan Sjogren,Jette G. Hemmingsen,Steffen Loft,Joakim H. Pagels,andErik SwietlickiEnvironmental Science Technology  2014, 48, 11, 6300-6308 (Article)ACS AuthorChoicePublication Date (Web):May 5, 2014ACS AuthorChoiceAbstractFull textPDFABSTRACTIn urban environments, airborne particles are continuously emitted, followed by atmospheric aging. Also, particles emitted elsewhere, transported by winds, contribute to the urban aerosol. We studied the effective density (mass-mobility relationship) and mixing state with respect to the density of particles in central Copenhagen, in wintertime. The results are related to particle origin, morphology, and aging. Using a differential mobility analyzer-aerosol particle mass analyzer (DMA-APM), we determined that particles in the diameter range of 50–400 nm were of two groups: porous soot aggregates and more dense particles. Both groups were present at each size in varying proportions. Two types of temporal variability in the relative number fraction of the two groups were found: soot correlated with intense traffic in a diel pattern and dense particles increased during episodes with long-range transport from polluted continental areas. The effective density of each group was relatively stable over time, especially of the soot aggregates, which had effective densities similar to those observed in laboratory studies of fresh diesel exhaust emissions. When heated to 300 °C, the soot aggregate volatile mass fraction was ∼10%. For the dense particles, the volatile mass fraction varied from ∼80% to nearly 100%.An Iodide-Adduct High-Resolution Time-of-Flight Chemical-Ionization Mass Spectrometer: Application to Atmospheric Inorganic and Organic CompoundsBen H. Lee,Felipe D. Lopez-Hilfiker,Claudia Mohr,Theo Kurtén,Douglas R. Worsnop,andJoel A. Thornton*Environmental Science Technology  2014, 48, 11, 6309-6317 (Article)Publication Date (Web):May 7, 2014AbstractFull textPDFABSTRACTA high-resolution time-of-flight chemical-ionization mass spectrometer (HR-ToF-CIMS) using Iodide-adducts has been characterized and deployed in several laboratory and field studies to measure a suite of organic and inorganic atmospheric species. The large negative mass defect of Iodide, combined with soft ionization and the high mass-accuracy ( 20 ppm) and mass-resolving power (R 5500) of the time-of-flight mass spectrometer, provides an additional degree of separation and allows for the determination of elemental compositions for the vast majority of detected ions. Laboratory characterization reveals Iodide-adduct ionization generally exhibits increasing sensitivity toward more polar or acidic volatile organic compounds. Simultaneous retrieval of a wide range of mass-to-charge ratios (m/Q from 25 to 625 Th) at a high frequency ( 1 Hz) provides a comprehensive view of atmospheric oxidative chemistry, particularly when sampling rapidly evolving plumes from fast moving platforms like an aircraft. We present the sampling protocol, detection limits and observations from the first aircraft deployment for an instrument of this type, which took place aboard the NOAA WP-3D aircraft during the Southeast Nexus (SENEX) 2013 field campaign. Remediation and Control Technologies Insoluble Fe-Humic Acid Complex as a Solid-Phase Electron Mediator for Microbial Reductive DechlorinationChunfang Zhang,Dongdong Zhang,Zhiling Li,Tetsuji Akatsuka,Suyin Yang,Daisuke Suzuki,andArata Katayama*Environmental Science Technology  2014, 48, 11, 6318-6325 (Article)Publication Date (Web):April 23, 2014AbstractFull textPDFABSTRACTWe report that the insoluble Fe-HA complex, which was synthesized with both commercial Aldrich humic acid (HA) and natural HA, functions as a solid-phase electron mediator (EM) for the anaerobic microbial dechlorination of pentachlorophenol. Spectroscopic characterizations and sequential Fe extraction demonstrated that the Fe-HA complex was predominated with Na4P2O7-labile Fe (represented as the organically bound Fe fraction) and poorly ordered Fe fraction (the fraction left in the residue after the sequential extraction), which were associated with different possible binding processes with carboxylate and phenolic groups. The change in the electron-mediating activity caused by Fe extraction indicated that the electron-mediating function of the Fe-HA complex is attributable to the Na4P2O7-labile Fe fraction. The Fe-HA complex also accelerated the microbial reduction of Fe(III) oxide, which suggested the presence of multiple electron-mediating functions in the complex. The electron shuttle assay showed that the Fe-HA complex had an electron-accepting capacity of 0.82 mequiv g–1 dry Fe-HA complex. The presence of redox-active moieties in the Fe-HA complex was verified by cyclic voltammetry analysis of the sample after electrical reduction, with a redox potential estimated at 0.02 V (vs a standard hydrogen electrode).Coupled Effects of Aging and Weak Magnetic Fields on Sequestration of Selenite by Zero-Valent IronLiping Liang,Xiaohong Guan*,Zhong Shi,Jialing Li,Yinan Wu,andPaul G. Tratnyek*Environmental Science Technology  2014, 48, 11, 6326-6334 (Article)ACS AuthorChoicePublication Date (Web):May 7, 2014ACS AuthorChoiceAbstractFull textPDFABSTRACTThe sequestration of Se(IV) by zero-valent iron (ZVI) is strongly influenced by the coupled effects of aging ZVI and the presence of a weak magnetic field (WMF). ZVI aged at pH 6.0 with MES as buffer between 6 and 60 h gave nearly constant rates of Se(IV) removal with WMF but with rate constants that are 10- to 100-fold greater than without. XANES analysis showed that applying WMF changes the mechanism of Se(IV) removal by ZVI aged for 6–60 h from adsorption followed by reduction to direct reduction. The strong correlation between Se(IV) removal and Fe2+ release suggests direct reduction of Se(IV) to Se(0) by Fe0, in agreement with the XANES analysis. The numerical simulation of ZVI magnetization revealed that the WMF influence on Se(IV) sequestration is associated mainly with the ferromagnetism of ZVI and the paramagnetism of Fe2+. In the presence of the WMF, the Lorentz force gives rise to convection in the solution, which narrows the diffusion layer, and the field gradient force, which tends to move paramagnetic ions (esp. Fe2+) along the higher field gradient at the ZVI particle surface, thereby inducing nonuniform depassivation and eventually localized corrosion of the ZVI surface. Sustainability Engineering and Green Chemistry Fabrication of Bioinspired Composite Nanofiber Membranes with Robust Superhydrophobicity for Direct Contact Membrane DistillationYuan Liao,Rong Wang*,andAnthony G. FaneEnvironmental Science Technology  2014, 48, 11, 6335-6341 (Article)Publication Date (Web):May 5, 2014AbstractFull textPDFABSTRACTThe practical application of membrane distillation (MD) for water purification is hindered by the absence of desirable membranes that can fulfill the special requirements of the MD process. Compared to the membranes fabricated by other methods, nanofiber membranes produced by electrospinning are of great interest due to their high porosity, low tortuosity, large surface pore size, and high surface hydrophobicity. However, the stable performance of the nanofiber membranes in the MD process is still unsatisfactory. Inspired by the unique structure of the lotus leaf, this study aimed to develop a strategy to construct superhydrophobic composite nanofiber membranes with robust superhydrophobicity and high porosity suitable for use in MD. The newly developed membrane consists of a superhydrophobic silica-PVDF composite selective skin formed on a polyvinylidene fluoride (PVDF) porous nanofiber scaffold via electrospinning. This fabrication method could be easily scaled up due to its simple preparation procedures. The effects of silica diameter and concentration on membrane contact angle, sliding angle, and MD performance were investigated thoroughly. For the first time, the direct contact membrane distillation (DCMD) tests demonstrate that the newly developed membranes are able to present stable high performance over 50 h of testing time, and the superhydrophobic selective layer exhibits excellent durability in ultrasonic treatment and a continuous DCMD test. It is believed that this novel design strategy has great potential for MD membrane fabrication.Zinc Interaction with Struvite During and After Mineral FormationAshaki A. Rouff*andKaren M. JuarezEnvironmental Science Technology  2014, 48, 11, 6342-6349 (Article)Publication Date (Web):May 5, 2014AbstractFull textPDFABSTRACTSorption of Zn with struvite was assessed both during and after mineral formation at pH 9.0 for 1–100 μM (0.065–6.54 mg L–1) aqueous Zn. The Zn loadings of recovered solids were lower when Zn was present during struvite precipitation compared to when Zn was added to struvite-bearing solutions. X-ray absorption fine structure spectroscopy confirmed that Zn added to struvite-bearing solutions at concentrations ≤5 μM sorbed as both octahedral and tetrahedral complexes (Zn–O 1.98–2.03 Å), with evidence for bidentate configuration (Zn–P 3.18 Å). Bidentate complexes were incorporated into the near-surface structure, contributing to distortion of the struvite ν3 PO43– band in the Fourier transform infrared spectra. At Zn concentrations 5 μM, tetrahedral monodentate adsorbates (Zn–O 1.98 Å) dominated, transitioning to a Zn-phosphate precipitate at 100 μM. When Zn is present during struvite precipitation, octahedral monodentate sorbates detected at 1 μM (Zn–O 2.08–2.10 Å; Zn–P 3.60–3.64 Å) polymerized at 5–50 μM, ultimately forming a Zn-hydroxide precipitate at 100 μM. The lowest initial Zn concentrations (0.065 mg L–1) and resultant solid loadings from precipitation experiments (13 mg kg–1) are consistent with those reported for struvite recovered from wastewater, suggesting that similar Zn sorption processes may occur in more complex systems.Fermentation of Glycerol into Ethanol in a Microbial Electrolysis Cell Driven by a Customized ConsortiumAllison M. Speers,Jenna M. Young,andGemma Reguera*Environmental Science Technology  2014, 48, 11, 6350-6358 (Article)Publication Date (Web):May 6, 2014AbstractFull textPDFABSTRACTThe in situ generation of ethanol from glycerol-containing wastewater shows promise to improve the economics of the biodiesel industry. Consequently, we developed a microbial electrolysis cell (MEC) driven by the synergistic metabolisms of the exoelectrogen Geobacter sulfurreducens and the bacterium Clostridium cellobioparum, which fermented glycerol into ethanol in high yields (90%) and produced fermentative byproducts that served as electron donors for G. sulfurreducens. Syntrophic cooperation stimulated glycerol consumption, ethanol production, and the conversion of fermentation byproducts into cathodic H2 in the MEC. The platform was further improved by adaptively evolving glycerol-tolerant strains with robust growth at glycerol loadings typical of biodiesel wastewater and by increasing the buffering capacity of the anode medium. This resulted in additional increases in glycerol consumption (up to 50 g/L) and ethanol production (up to 10 g/L) at rates that greatly exceeded the capacity of the anode biofilms to concomitantly remove the fermentation byproducts. As a result, 1,3-propanediol was generated as a metabolic sink for electrons not converted into electricity syntrophically. The results highlight the potential of consortia to process glycerol in MECs and provide insights into genetic engineering and system design approaches that can be implemented to further improve MEC performance to satisfy industrial needs. Ecotoxicology and Human Environmental Health Accumulation and Hazard Assessment of Mercury to Waterbirds at Lake Chapala, MexicoZaria Torres,Miguel A. Mora*,Robert J. Taylor,Dioselina Alvarez-Bernal,Hector R. Buelna,andAyumi HyodoEnvironmental Science Technology  2014, 48, 11, 6359-6365 (Article)Publication Date (Web):May 2, 2014AbstractFull textPDFABSTRACTLake Chapala is the largest tropical lake in Mexico. The objectives of this study were to determine bioaccumulation of Hg in fish and to evaluate the potential impacts of Hg in the diet of aquatic birds, particularly the American white pelican (AWPE), in Lake Chapala. Hg concentrations in three fish species ranged from 0.021 to 0.568 μg/g wet weight. Mercury in fish was positively and significantly correlated with total fish length (R2 = 0.44, P 0.05). The δ15N values in fish were significantly correlated with Hg concentrations in Chapala and the San Antonio Reservoir (R2 = 0.69, P 0.001 and R2 = 0.40, P 0.001, respectively). However, Hg concentrations in bird feathers were not significantly different between years, among locations, or among species. Hg concentrations in fish from Lake Chapala were within values reported in many parts of the world. The Hg (mean range of 2.75 to 4.54 μg/g dw) and δD (mean range of −62‰ to −11‰) values in bird feathers suggested a wide pattern of exposure for highly migratory AWPE and egrets, although birds with lower δD values in feathers appeared to have greater concentrations of Hg than those with higher δD values. Contaminant exposure in aquatic birds in Chapala during the breeding season should be monitored next to better determine the potential effects of Hg on resident aquatic birds.Co-occurrence of Estrogenic and Antiestrogenic Activities in Wastewater: Quantitative Evaluation of Balance by in Vitro ERα Reporter Gene Assay and Chemical AnalysisMasaru Ihara*,Mariko O. Ihara,Vimal Kumar,Masanori Narumiya,Seiya Hanamoto,Norihide Nakada,Naoyuki Yamashita,Shinichi Miyagawa,Taisen Iguchi,andHiroaki TanakaEnvironmental Science Technology  2014, 48, 11, 6366-6373 (Article)Publication Date (Web):May 6, 2014AbstractFull textPDFABSTRACTEndocrine-disrupting chemicals are exogenous substances that alter the function of the endocrine system, with adverse health effects on organisms or their progeny. In vitro estrogen receptor (ER) reporter gene assays have long been used to measure estrogenic activity in wastewater. Nevertheless, there is still uncertainty about their usefulness in environmental monitoring on account of a discrepancy between the estrogenic response of the in vitro assay and concentrations of estrogenic compounds determined by chemical analysis. Here, we measured estrogenic and antiestrogenic activities in wastewater by ERα reporter gene assay. All samples were simultaneously analyzed for estrone, 17β-estradiol, estriol, and 17α-ethynylestradiol, and the concentrations were used to predict estrogenic activity. All samples in which measured estrogenic activity was significantly lower than predicted showed strong antiestrogenic activity. In addition, we confirmed that the fraction that did not have antiestrogenic activity showed stronger estrogenic activity than the unfractionated wastewater extract. These results indicate that antiestrogenic compounds in wastewater suppress the activity of natural estrogens, and the reporter gene assay represents the net activity.Differential Effect of Solar Light in Increasing the Toxicity of Silver and Titanium Dioxide Nanoparticles to a Fish Cell Line and Zebrafish EmbryosSaji George*,Hannah Gardner, Eng Khuan Seng,Hengky Chang,Chunyan Wang,Crystal Hay Yu Fang,Mark Richards,Suresh Valiyaveettil,andWoon Khiong ChanEnvironmental Science Technology  2014, 48, 11, 6374-6382 (Article)Publication Date (Web):May 8, 2014AbstractFull textPDFABSTRACTThe increasing use of silver (Ag) and titanium dioxide (TiO2) nanoparticles (NPs) in consumer products and their inevitable seepage into the environment prompted us to investigate their potential toxicity to a fish cell line (BF-2) and zebrafish embryos under dark and Simulated Solar Light (SSL) exposure conditions. Using high throughput screening (HTS) platforms, we showed that the oxidative stress-dependent cytotoxicity and embryonic toxicity of NPs were significantly increased upon exposure to SSL. While, the toxicity of TiO2 NPs under SSL exposure could be explained by hydroxyl radical generation, the enhanced toxicity of Ag NPs under SSL exposure was due to surface oxidation and physicochemical modification of Ag NPs and shedding of Ag+, leading to an increased bioavailability of silver. Our observations that solar light could induce physicochemical transformation of TiO2 and Ag NPs and enhance their toxic potential emphasizes the need for conducting future toxicity studies under environmentally relevant exposure conditions to guide decision making on the safe handling of NPs.Regulation of Microcystin-LR-Induced Toxicity in Mouse Spermatogonia by miR-96Yuan Zhou,Zou Xiang,Dongmei Li*,andXiaodong Han*Environmental Science Technology  2014, 48, 11, 6383-6390 (Article)Publication Date (Web):May 6, 2014AbstractFull textPDFABSTRACTMicrocystin (MC)-LR is a cyclic heptapeptide that acts as a potent reproductive system toxin, especially by decreasing sperm quality through affecting spermatogonia. However, the molecular mechanisms of MC-induced spermatogonial cytotoxicity still remain unclear. The present study was designed to investigate changes in microRNA (miRNA) profiles and their potential functions in spermatogonia (GC-1 cell line) following treatment with MC-LR. With microarray analysis, 101 miRNAs were identified to be significantly altered in GC-1 cells treated with MC-LR. Among the 25 miRNAs associated with spermatogenesis, miR-96 was down-regulated most dramatically and thus selected for further functional analysis. Deleted-in azoospermia-associated protein 2 (DAZAP2) was predicted to have a binding sequence for miR-96 within its 3′-untranslated region. Fluorescent reporter assay confirmed that DAZAP2 was the target gene of miR-96. The expression of DAZAP2 decreased significantly when miR-96 was up-regulated. Consistently, down-regulation of miR-96 significantly increased the level of DAZAP2. Up-regulation of miR-96 promoted cell viability in GC-1 cells as a result of exposure to MC-LR. Our study suggested a crucial role for miR-96 in the regulation of cytotoxic effects of MC-LR in spermatogonia, which provides new perspectives in the diagnosis and treatment strategies for MC-induced male infertility.Characterization of Food-Grade Titanium Dioxide: The Presence of Nanosized ParticlesYu Yang*,Kyle Doudrick*,Xiangyu Bi,Kiril Hristovski,Pierre Herckes,Paul Westerhoff,andRalf KaegiEnvironmental Science Technology  2014, 48, 11, 6391-6400 (Article)Publication Date (Web):April 22, 2014AbstractFull textPDFABSTRACTTitanium dioxide (TiO2) is widely used in food products, which will eventually enter wastewater treatment plants and terrestrial or aquatic environments, yet little is known about the fraction of this TiO2 that is nanoscale, or the physical and chemical properties of TiO2 that influence its human and environmental fate or toxicity. Instead of analyzing TiO2 properties in complex food or environmental samples, we procured samples of food-grade TiO2 obtained from global food suppliers and then, using spectroscopic and other analytical techniques, quantified several parameters (elemental composition, crystal structure, size, and surface composition) that are reported to influence environmental fate and toxicity. Another sample of nano-TiO2 that is generally sold for catalytic applications (P25) and widely used in toxicity studies, was analyzed for comparison. Food-grade and P25 TiO2 are engineered products, frequently synthesized from purified titanium precursors, and not milled from bulk scale minerals. Nanosized materials were present in all of the food-grade TiO2 samples, and transmission electron microscopy showed that samples 1–5 contained 35, 23, 21, 17, and 19% of nanosized primary particles ( 100 nm in diameter) by number, respectively (all primary P25 particles were 100 nm in diameter). Both types of TiO2 aggregated in water with an average hydrodynamic diameter of 100 nm. Food-grade samples contained phosphorus (P), with concentrations ranging from 0.5 to 1.8 mg of P/g of TiO2. The phosphorus content of P25 was below inductively coupled plasma mass spectrometry detection limits. Presumably because of a P-based coating detected by X-ray photoelectron spectroscopy, the ζ potential of the food-grade TiO2 suspension in deionized water ranged from −10 to −45 mV around pH 7, and the iso-electric point for food-grade TiO2 ( pH 4) was significantly lower than that for P25. The presence of other elements in or on the TiO2 (Si content of 0.026–0.062% and Al content of 0.0006–0.810%) was also different from the case for P25 and would influence the environmental fate of TiO2. X-ray diffraction analysis confirmed the presence of anatase and/or rutile in the food-grade materials, and although the presence of amorphous TiO2 could not be ruled out, it is unlikely on the basis of Raman analysis. The food-grade TiO2 was solar photoactive. Cationic dyes adsorbed more readily to food-grade TiO2 than P25, indicating very different potentials for interaction with organics in the environment. This research shows that food-grade TiO2 contains engineered nanomaterials with properties quite different from those of P25, which has previously been used in many ecotoxicity studies, and because food-grade TiO2 is more likely than P25 to enter the environment (i.e., potentially higher exposure levels), there is a need to design environmental (and human) fate and toxicity studies comparing food-grade to catalytic TiO2.Uranium in Larval Shells As a Barometer of Molluscan Ocean Acidification ExposureChristina A. Frieder*,Jennifer P. Gonzalez,andLisa A. LevinEnvironmental Science Technology  2014, 48, 11, 6401-6408 (Article)Publication Date (Web):May 5, 2014AbstractFull textPDFABSTRACTAs the ocean undergoes acidification, marine organisms will become increasingly exposed to reduced pH, yet variability in many coastal settings complicates our ability to accurately estimate pH exposure for those organisms that are difficult to track. Here we present shell-based geochemical proxies that reflect pH exposure from laboratory and field settings in larvae of the mussels Mytilus californianus and M. galloprovincialis. Laboratory-based proxies were generated from shells precipitated at pH 7.51 to 8.04. U/Ca, Sr/Ca, and multielemental signatures represented as principal components varied with pH for both species. Of these, U/Ca was the best predictor of pH and did not vary with larval size, with semidiurnal pH fluctuations, or with oxygen concentration. Field applications of U/Ca were tested with mussel larvae reared in situ at both known and unknown pH conditions. Larval shells precipitated in a region of greater upwelling had higher U/Ca, and these U/Ca values corresponded well with the laboratory-derived U/Ca-pH proxy. Retention of the larval shell after settlement in molluscs allows use of this geochemical proxy to assess ocean acidification effects on marine populations.Identifying Early Urinary Metabolic Changes with Long-Term Environmental Exposure to Cadmium by Mass-Spectrometry-Based MetabolomicsYanhong Gao,Yonghai Lu,Shaomin Huang,Liang Gao,Xuxia Liang,Yongning Wu,Jing Wang,Qiong Huang,Liuying Tang,Guian Wang,Fei Yang,Shuguang Hu,Zihui Chen,Ping Wang,Qi Jiang,Rui Huang,Yinghua Xu,Xingfen Yang*,andChoon Nam Ong*Environmental Science Technology  2014, 48, 11, 6409-6418 (Article)Publication Date (Web):May 8, 2014AbstractFull textPDFABSTRACTCadmium (Cd) is a common environmental pollutant, and urinary Cd (UCd) is generally used as a marker of exposure; however, our understanding on the related urinary metabolic changes caused by Cd exposure is still not clear. In this study, we applied a mass-spectrometry-based metabolomic approach to assess the urinary metabolic changes in human with long-term environmental Cd exposure, aimed to identify early biomarkers to assess Cd nephrotoxicity. Urine samples from 94 female never smokers aged 44–70 with UCd in the range of 0.20–68.67 μg/L were analyzed by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-ToF-MS) and gas chromatography–mass spectrometry (GC–MS). It was found that metabolites related to amino acid metabolism (l-glutamine, l-cystine, l-tyrosine, N-methyl-l-histidine, l-histidinol, taurine, phenylacetylglutamine, hippurate, and pyroglutamic acid), galactose metabolism (d-galactose and myo-inositol), purine metabolism (xanthine, urea, and deoxyadenosine monophosphate), creatine pathway (creatine and creatinine), and steroid hormone biosynthesis (17-α-hydroxyprogesterone, tetrahydrocortisone, estrone, and corticosterone) were significantly higher among those with a UCd level higher than 5 μg/L. Moreover, we noticed that the level of N-methyl-l-histidine had already started to elevate among individuals with a UCd concentration of ≥2 μg/L. The overall findings illustrate that metabolomics offer a useful approach for revealing metabolic changes as a result of Cd exposure.Effects of Surface-Engineered Nanoparticle-Based Dispersants for Marine Oil Spills on the Model Organism Artemia franciscanaApril L. Rodd,Megan A. Creighton,Charles A. Vaslet,J. Rene Rangel-Mendez,Robert H. Hurt*,andAgnes B. Kane*Environmental Science Technology  2014, 48, 11, 6419-6427 (Article)ACS AuthorChoicePublication Date (Web):May 13, 2014ACS AuthorChoiceAbstractFull textPDFABSTRACTFine particles are under active consideration as alternatives to chemical dispersants for large-scale petroleum spills. Fine carbon particles with engineered surface chemistry have been shown to stabilize oil-in-water emulsions, but the environmental impacts of large-scale particle introduction to the marine environment are unknown. Here we study the impact of surface-engineered carbon-black materials on brine shrimp (Artemia franciscana) as a model marine microcrustacean. Mortality was characterized at 50–1000 mg/L, and levels of heat shock protein 70 (hsp70) were characterized at sublethal particle concentrations (25–50 mg/L). Functionalized carbon black (CB) nanoparticles were found to be nontoxic at all concentrations, while hydrophobic (annealed) and as-produced CB induced adverse effects at high concentrations. CB was also shown to adsorb benzene, a model hydrocarbon representing the more soluble and toxic low-molecular weight aromatic fraction of petroleum, but the extent of adsorption was insufficient to mitigate benzene toxicity to Artemia in coexposure experiments. At lower benzene concentrations (25–75 mg/L), coexposure with annealed and as-produced CB increased hsp70 protein levels. This study suggests that surface functionalization for increased hydrophilicity can not only improve the performance of CB-based dispersants but also reduce their adverse environmental impacts on marine organisms.Ecological Modeling for the Extrapolation of Ecotoxicological Effects Measured during in Situ Assays in GammarusRomain Coulaud,Olivier Geffard,Amandine Coquillat,Hervé Quéau,Sandrine Charles,andArnaud Chaumot*Environmental Science Technology  2014, 48, 11, 6428-6436 (Article)Publication Date (Web):May 7, 2014AbstractFull textPDFABSTRACTEvaluating the effects of chemical contamination on populations and ecological communities still constitutes a challenging necessity in environmental management. However, the toxic effects of contaminants are commonly measured by means of organism-level responses. Linking such effects measures with ecological models is a promising way to determine population-level impacts. In this way, population models are currently increasingly used in predictive risk assessment procedures, but their use in environmental diagnostic framework remains limited due to their lack of ecological realism. The present study with the crustacean Gammarus fossarum, a sentinel species in freshwater monitoring, combines a dual field and laboratory experimental approach with a population modeling framework. In this way, we developed an ecologically relevant periodic matrix population model for Gammarus. This model allowed us to capture the population dynamics in the field, and to understand the particular pattern of demographic sensitivities induced by Gammarus life-history phenology. The model we developed provided a robust population-level assessment of in situ-based effects measures recorded during a biomonitoring program on a French watershed impacted by past mining activities. Thus, our study illustrates the potential of population modeling when seeking to decipher the role of environmental toxic contamination in ecological perturbations. Energy and the Environment Experimental Results from RO-PRO: A Next Generation System for Low-Energy DesalinationAndrea Achilli,Jeri L. Prante,Nathan T. Hancock,Eric B. Maxwell,andAmy E. Childress*Environmental Science Technology  2014, 48, 11, 6437-6443 (Article)Publication Date (Web):May 5, 2014AbstractFull textPDFABSTRACTA pilot system was designed and constructed to evaluate reverse osmosis (RO) energy reduction that can be achieved using pressure-retarded osmosis (PRO). The RO-PRO experimental system is the first known system to utilize energy from a volume of water transferred from atmospheric pressure to elevated pressure across a semipermeable membrane to prepressurize RO feedwater. In other words, the system demonstrated that pressure could be exchanged between PRO and RO subsystems. Additionally, the first experimental power density data for a RO-PRO system is now available. Average experimental power densities for the RO-PRO system ranged from 1.1 to 2.3 W/m2. This is higher than previous river-to-sea PRO pilot systems (1.5 W/m2) and closer to the goal of 5 W/m2 that would make PRO an economically feasible technology. Furthermore, isolated PRO system testing was performed to evaluate PRO element performance with higher cross-flow velocities and power densities exceeding 8 W/m2 were achieved with a 28 g/L NaCl draw solution. From this empirical data, inferences for future system performance can be drawn that indicate future RO-PRO systems may reduce the specific energy requirements for desalination by ∼1 kWh/m3.High Sensitivity of Diesel Soot Morphological and Optical Properties to Combustion Temperature in a Shock TubeChong Qiu*,Alexei F. Khalizov,Brian Hogan,Eric L. Petersen,andRenyi Zhang*Environmental Science Technology  2014, 48, 11, 6444-6452 (Article)Publication Date (Web):May 6, 2014AbstractFull textPDFABSTRACTCarbonaceous particles produced from combustion of fossil fuels have strong impacts on air quality and climate, yet quantitative relationships between particle characteristics and combustion conditions remain inadequately understood. We have used a shock tube to study the formation and properties of diesel combustion soot, including particle size distributions, effective density, elemental carbon (EC) mass fraction, mass-mobility scaling exponent, hygroscopicity, and light absorption and scattering. These properties are found to be strongly dependent on the combustion temperature and fuel equivalence ratio. Whereas combustion at higher temperatures (∼2000 K) yields fractal particles of a larger size and high EC content (90 wt %), at lower temperatures (∼1400 K) smaller particles of a higher organic content (up to 65 wt %) are produced. Single scattering albedo of soot particles depends largely on their organic content, increasing drastically from 0.3 to 0.8 when the particle EC mass fraction decreases from 0.9 to 0.3. The mass absorption cross-section of diesel soot increases with combustion temperature, being the highest for particles with a higher EC content. Our results reveal that combustion conditions, especially the temperature, may have significant impacts on the direct and indirect climate forcing of atmospheric soot aerosols.Light-Duty Vehicle CO2 Targets Consistent with 450 ppm CO2 StabilizationSandra L. Winkler*,Timothy J. Wallington,Heiko Maas,andHeinz HassEnvironmental Science Technology  2014, 48, 11, 6453-6460 (Article)Publication Date (Web):May 5, 2014AbstractFull textPDFABSTRACTWe present a global analysis of CO2 emission reductions from the light-duty vehicle (LDV) fleet consistent with stabilization of atmospheric CO2 concentration at 450 ppm. The CO2 emission reductions are described by g CO2/km emission targets for average new light-duty vehicles on a tank-to-wheel basis between 2010 and 2050 that we call CO2 glide paths. The analysis accounts for growth of the vehicle fleet, changing patterns in driving distance, regional availability of biofuels, and the changing composition of fossil fuels. New light-duty vehicle fuel economy and CO2 regulations in the U.S. through 2025 and in the EU through 2020 are broadly consistent with the CO2 glide paths. The glide path is at the upper end of the discussed 2025 EU range of 68–78 g CO2/km. The proposed China regulation for 2020 is more stringent than the glide path, while the 2017 Brazil regulation is less stringent. Existing regulations through 2025 are broadly consistent with the light-duty vehicle sector contributing to stabilizing CO2 at approximately 450 ppm. The glide paths provide long-term guidance for LDV powertrain/fuel development.Pollutant Emissions and Energy Efficiency of Chinese Gasifier Cooking Stoves and Implications for Future Intervention StudiesEllison M. Carter*,Ming Shan,Xudong Yang,Jiarong Li,andJill BaumgartnerEnvironmental Science Technology  2014, 48, 11, 6461-6467 (Article)Publication Date (Web):May 2, 2014AbstractFull textPDFABSTRACTHousehold air pollution from solid fuel combustion is the leading environmental health risk factor globally. In China, almost half of all homes use solid fuel to meet their household energy demands. Gasifier cookstoves offer a potentially affordable, efficient, and low-polluting alternative to current solid fuel combustion technology, but pollutant emissions and energy efficiency performance of this class of stoves are poorly characterized. In this study, four Chinese gasifier cookstoves were evaluated for their pollutant emissions and efficiency using the internationally recognized water boiling test (WBT), version 4.1.2. WBT performance indicators included PM2.5, CO, and CO2 emissions and overall thermal efficiency. Laboratory investigation also included evaluation of pollutant emissions (PM2.5 and CO) under stove operating conditions designed to simulate common Chinese cooking practices. High power average overall thermal efficiencies ranged from 22 to 33%. High power average PM2.5 emissions ranged from 120 to 430 mg/MJ of useful energy, and CO emissions ranged from 1 to 30 g/MJ of useful energy. Compared with several widely disseminated \"improved” cookstoves selected from the literature, on average, the four Chinese gasifier cookstoves had lower PM2.5 emissions and higher CO emissions. The recent International Organization for Standardization (ISO) International Workshop Agreement on tiered cookstove ranking was developed to help classify stove performance and identify the best-performing stoves. The results from this study highlight potential ways to further improve this approach. Medium power stove operation emitted nearly twice as much PM2.5 as was emitted during high power stove operation, and the lighting phase of a cooking event contributed 45% and 34% of total PM2.5 emissions (combined lighting and cooking). Future approaches to laboratory-based testing of advanced cookstoves could improve to include greater differentiation between different modes of stove operation, beyond those evaluated with the WBT.Effects of Temperature and Hydraulic Retention Time on Acetotrophic Pathways and Performance in High-Rate Sludge DigestionDang Ho,Paul Jensen,andDamien Batstone*Environmental Science Technology  2014, 48, 11, 6468-6476 (Article)Publication Date (Web):May 5, 2014AbstractFull textPDFABSTRACTHigh-rate anaerobic digestion of organic solids requires rapid hydrolysis and enhanced methanogenic growth rates, which can be achieved through elevated temperature ( 55 °C) at short hydraulic retention times (HRT). This study assesses the effect of temperatures between 55 °C and 65 °C and HRTs between 2 and 4 days on process performance, microbial community structure, microbial capability, and acetotrophic pathways in thermophilic anaerobic reactors. Increasing the temperature did not enhance volatile solids (VS) destruction above the base value of 37% achieved at 55 °C and 4 days HRT. Stable isotopic signatures (δ13C) revealed that elevated temperature promoted syntrophic acetate oxidation, which accounted for 60% of the methane formation at 55 °C, and increasing substantially to 100% at 65 °C. The acetate consumption capacity dropped with increasing temperature (from 0.69–0.81 gCOD gVS–1 d–1 at 55 °C to 0.21–0.35 gCOD gVS–1 d–1 at 65 °C), based on specific activity testing of reactor contents. Community analysis using 16S rRNA pyrosequencing revealed the dominance of Methanosarcina at 55–60 °C. However, a further increase to 65 °C resulted in loss of Methanosarcina, with an accumulation of organic acids and reduced methane production. Similar issues were observed when reducing the HRT to 2 days, indicating that temperature 60 °C and HRT 3 days are critical to operate these systems stably.Emissions from South Asian Brick ProductionCheryl Weyant,Vasudev Athalye,Santhosh Ragavan,Uma Rajarathnam,Dheeraj Lalchandani,Sameer Maithel,Ellen Baum,andTami C. Bond*Environmental Science Technology  2014, 48, 11, 6477-6483 (Article)Publication Date (Web):April 15, 2014AbstractFull textPDFABSTRACTThirteen South Asian brick kilns were tested to quantify aerosol and gaseous pollutant emissions. Particulate matter (PM2.5), carbon monoxide (CO), and optical scattering and absorption measurements in the exhaust of six kiln technologies demonstrate differences in overall emission profiles and relative climate warming resulting from kiln design and fuel choice. Emission factors differed between kiln types, in some cases by an order of magnitude. The kilns currently dominating the sector had the highest emission factors of PM2.5 and light absorbing carbon, while improved Vertical Shaft and Tunnel kilns were lower emitters. An improved version of the most common technology in the region, the zig-zag kiln, was among the lowest emitting kilns in PM2.5, CO, and light absorbing carbon. Emission factors measured here are lower than those currently used in emission inventories as inputs to global climate models; 85% lower (PM2.5) and 35% lower for elemental carbon (EC) for the most common kiln in the region, yet the ratio of EC to total carbon was higher than previously estimated (0.96 compared to 0.47). Total annual estimated emissions from the brick industry are 120 Tg CO2, 2.5 Tg CO, 0.19 Tg PM2.5, and 0.12 Tg EC.Emissions and Climate-Relevant Optical Properties of Pollutants Emitted from a Three-Stone Fire and the Berkeley-Darfur Stove Tested under Laboratory ConditionsChelsea V. Preble,Odelle L. Hadley,Ashok J. Gadgil,andThomas W. Kirchstetter*Environmental Science Technology  2014, 48, 11, 6484-6491 (Article)Publication Date (Web):March 31, 2014AbstractFull textPDFABSTRACTCooking in the developing world generates pollutants that endanger the health of billions of people and contribute to climate change. This study quantified pollutants emitted when cooking with a three-stone fire (TSF) and the Berkeley-Darfur Stove (BDS), the latter of which encloses the fire to increase fuel efficiency. The stoves were operated at the Lawrence Berkeley National Laboratory testing facility with a narrow range of fuel feed rates to minimize performance variability. Fast (1 Hz) measurements of pollutants enabled discrimination between the stoves’ emission profiles and development of woodsmoke-specific calibrations for the aethalometer (black carbon, BC) and DustTrak (fine particles, PM2.5). The BDS used 65 ± 5% (average ±95% confidence interval) of the wood consumed by the TSF and emitted 50 ± 5% of the carbon monoxide emitted by the TSF for an equivalent cooking task, indicating its higher thermal efficiency and a modest improvement in combustion efficiency. The BDS reduced total PM2.5 by 50% but achieved only a 30% reduction in BC emissions. The BDS-emitted particles were, therefore, more sunlight-absorbing: the average single scattering albedo at 532 nm was 0.36 for the BDS and 0.47 for the TSF. Mass emissions of PM2.5 and BC varied more than emissions of CO and wood consumption over all tests, and emissions and wood consumption varied more among TSF than BDS tests. The international community and the Global Alliance for Clean Cookstoves have proposed performance targets for the highest tier of cookstoves that correspond to greater reductions in fuel consumption and PM2.5 emissions of approximately 65% and 95%, respectively, compared to baseline cooking with the TSF. Given the accompanying decrease in BC emissions for stoves that achieve this stretch goal and BC’s extremely high global warming potential, the short-term climate change mitigation from avoided BC emissions could exceed that from avoided CO2 emissions.Biofuels from Pyrolysis in Perspective: Trade-offs between Energy Yields and Soil-Carbon AdditionsDominic Woolf*,Johannes Lehmann,Elizabeth M. Fisher,andLargus T. AngenentEnvironmental Science Technology  2014, 48, 11, 6492-6499 (Article)Publication Date (Web):April 30, 2014AbstractFull textPDFABSTRACTCoproduction of biofuels with biochar (the carbon-rich solid formed during biomass pyrolysis) can provide carbon-negative bioenergy if the biochar is sequestered in soil, where it can improve fertility and thus simultaneously address issues of food security, soil degradation, energy production, and climate change. However, increasing biochar production entails a reduction in bioenergy obtainable per unit biomass feedstock. Quantification of this trade-off for specific biochar–biofuel pathways has been hampered by lack of an accurate-yet-simple model for predicting yields, product compositions, and energy balances from biomass slow pyrolysis. An empirical model of biomass slow pyrolysis was developed and applied to several pathways for biochar coproduction with gaseous and liquid biofuels. Here, we show that biochar production reduces liquid biofuel yield by at least 21 GJ Mg–1 C (biofuel energy sacrificed per unit mass of biochar C), with methanol synthesis giving this lowest energy penalty. For gaseous-biofuel production, the minimum energy penalty for biochar production is 33 GJ Mg–1 C. These substitution rates correspond to a wide range of Pareto-optimal system configurations, implying considerable latitude to choose pyrolysis conditions to optimize for desired biochar properties or to modulate energy versus biochar yields in response to fluctuating price differentials for the two commodities.One for Two: Conversion of Waste Chicken Feathers to Carbon Microspheres and (NH4)HCO3Lei Gao,Haibo Hu,Xuelin Sui,Changle Chen*,andQianwang Chen*Environmental Science Technology  2014, 48, 11, 6500-6507 (Article)Publication Date (Web):April 25, 2014AbstractFull textPDFABSTRACTPyrolysis of 1 g of waste chicken feathers (quills and barbs) in supercritical carbon dioxide (sc-CO2) system at 600 °C for 3 h leads to the formation of 0.25 g well-shaped carbon microspheres with diameters of 1–5 μm and 0.26 g ammonium bicarbonate ((NH4)HCO3). The products were characterized by powder X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Raman spectroscopic, FT-IR spectrum, X-ray electron spectroscopy (XPS), and N2 adsorption/desorption measurements. The obtained carbon microspheres displayed great superhydrophobicity as fabric coatings materials, with the water contact angle of up to 165.2 ± 2.5°. The strategy is simple, efficient, does not require any toxic chemicals or catalysts, and generates two valuable materials at the same time. Moreover, other nitrogen-containing materials (such as nylon and amino acids) can also be converted to carbon microspheres and (NH4)HCO3 in the sc-CO2 system. This provides a simple strategy to extract the nitrogen content from natural and man-made waste materials and generate (NH4)HCO3 as fertilizer.Temporal Changes in Microbial Ecology and Geochemistry in Produced Water from Hydraulically Fractured Marcellus Shale Gas WellsMaryam A. Cluff,Angela Hartsock,Jean D. MacRae,Kimberly Carter,andPaula J. Mouser*Environmental Science Technology  2014, 48, 11, 6508-6517 (Article)Publication Date (Web):May 6, 2014AbstractFull textPDFABSTRACTMicroorganisms play several important roles in unconventional gas recovery, from biodegradation of hydrocarbons to souring of wells and corrosion of equipment. During and after the hydraulic fracturing process, microorganisms are subjected to harsh physicochemical conditions within the kilometer-deep hydrocarbon-bearing shale, including high pressures, elevated temperatures, exposure to chemical additives and biocides, and brine-level salinities. A portion of the injected fluid returns to the surface and may be reused in other fracturing operations, a process that can enrich for certain taxa. This study tracked microbial community dynamics using pyrotag sequencing of 16S rRNA genes in water samples from three hydraulically fractured Marcellus shale wells in Pennsylvania, USA over a 328-day period. There was a reduction in microbial richness and diversity after fracturing, with the lowest diversity at 49 days. Thirty-one taxa dominated injected, flowback, and produced water communities, which took on distinct signatures as injected carbon and electron acceptors were attenuated within the shale. The majority ( 90%) of the community in flowback and produced fluids was related to halotolerant bacteria associated with fermentation, hydrocarbon oxidation, and sulfur-cycling metabolisms, including heterotrophic genera Halolactibacillus, Vibrio, Marinobacter, Halanaerobium, and Halomonas, and autotrophs belonging to Arcobacter. Sequences related to halotolerant methanogenic genera Methanohalophilus and Methanolobus were detected at low abundance ( 2%) in produced waters several months after hydraulic fracturing. Five taxa were strong indicators of later produced fluids. These results provide insight into the temporal trajectory of subsurface microbial communities after \"fracking” and have important implications for the enrichment of microbes potentially detrimental to well infrastructure and natural gas fouling during this process. Correspondence The Confounding Effects of Dissolved Humic Acid on the Oxidation of Simple Substituted Phenols by Permanganate: Comment on \"Reinvestigation of the Role of Humic Acid in the Oxidation of Phenols by Permanganate”Su−Yan Pang,Qiang Wang,andJin Jiang*Environmental Science Technology  2014, 48, 11, 6518-6519 (Correspondence/Rebuttal)Publication Date (Web):May 16, 2014First PageFull textPDFResponse to Comment on \"Reinvestigation of the Role of Humic Acid in the Oxidation of Phenols by Permanganate”Bo Sun,Xinmei Xiong,Gongming Zhou,andXiaohong Guan*Environmental Science Technology  2014, 48, 11, 6520-6521 (Correspondence/Rebuttal)Publication Date (Web):May 16, 2014First PageFull textPDF Additions and Corrections Correction to Transport Zonation Limits Coupled Nitrification-Denitrification in Permeable SedimentsAdam J. Kessler,Ronnie N. Glud,M. Bayani Cardenas,andPerran L. M. CookEnvironmental Science Technology  2014, 48, 11, 6522 (Addition/Correction)Publication Date (Web):May 22, 2014First PageFull textPDF This website uses cookies to improve your user experience. By continuing to use the site, you are accepting our use of cookies. Read the ACS privacy policy. CONTINUE