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Environmental Science. Processes & Impacts

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https://www.readbyqxmd.com/read/27892563/using-reference-materials-to-improve-the-quality-of-data-generated-by-usepa-analytical-methods
#1
S J Nagourney, S A Wilson, S E Long
The quality of data generated for the analysis of environmental samples is critical to State and Federal regulatory agencies to ensure that decisions based upon the amounts of contaminants in environmental samples are truly protective of public health. The quality and validation of these measurements using the approved analytical methodology could be significantly enhanced by incorporating certified reference materials as part of the quality control protocols, yet this has not been widely implemented. Data from certified reference materials can provide critical information that can impact assessments regarding data use that is unavailable by other means...
November 28, 2016: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/27886312/standardisation-of-a-european-measurement-method-for-the-determination-of-anions-and-cations-in-pm2-5-results-of-field-trial-campaign-and-determination-of-measurement-uncertainty
#2
Sonya Beccaceci, Richard J C Brown, David M Butterfield, Peter M Harris, René P Otjes, Caroline van Hoek, Ulla Makkonen, Maria Catrambone, Rosalía Fernández Patier, Marc M G Houtzager, Jean-Philippe Putaud
European Committee for Standardisation (CEN) Technical Committee 264 'Air Quality' has recently produced a standard method for the measurements of anions and cations in PM2.5 within its Working Group 34 in response to the requirements of European Directive 2008/50/EC. It is expected that this method will be used in future by all Member States making measurements of the ionic content of PM2.5. This paper details the results of a field measurement campaign and the statistical analysis performed to validate this method, assess its uncertainty and define its working range to provide clarity and confidence in the underpinning science for future users of the method...
November 25, 2016: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/27878175/synergistic-effects-of-mining-and-urban-effluents-on-the-level-and-distribution-of-methylmercury-in-a-shallow-aquatic-ecosystem-of-the-bolivian-altiplano
#3
L Alanoca, S Guédron, D Amouroux, S Audry, M Monperrus, E Tessier, S Goix, D Acha, P Seyler, D Point
Lake Uru Uru (3686 m a.s.l.) located in the Bolivian Altiplano region receives both mining effluents and urban wastewater discharges originating from the surrounding local cities which are under rapid development. We followed the spatiotemporal distribution of different mercury (Hg) compounds and other metal(oid)s (e.g., Fe, Mn, Sb, Ti and W) in both water and sediments during the wet and dry seasons along a north-south transect of this shallow lake system. Along the transect, the highest Hg and metal(oid) concentrations in both water and sediments were found downstream of the confluences with mining effluents...
November 23, 2016: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/27874899/exposure-assessment-of-natural-uranium-from-drinking-water
#4
Rajan Jakhu, Rohit Mehra, H M Mittal
The uranium concentration in the drinking water of the residents of the Jaipur and Ajmer districts of Rajasthan has been measured for exposure assessment. The daily intake of uranium from the drinking water for the residents of the study area is found to vary from 0.4 to 123.9 μg per day. For the average uranium ingestion rate of 35.2 μg per day for a long term exposure period of 60 years, estimations have been made for the retention of uranium in different body organs and its excretion with time using ICRP's biokinetic model of uranium...
November 22, 2016: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/27841883/determining-time-weighted-average-concentrations-of-nitrate-and-ammonium-in-freshwaters-using-dgt-with-ion-exchange-membrane-based-binding-layers
#5
Jianyin Huang, William W Bennett, David T Welsh, Peter R Teasdale
Commercially-available AMI-7001 anion exchange and CMI-7000 cation exchange membranes were utilised as binding layers for DGT measurements of NO3-N and NH4-N in freshwaters. These ion exchange membranes are easier to prepare and handle than DGT binding layers consisting of hydrogels cast with ion exchange resins. The membranes showed good uptake and elution efficiencies for both NO3-N and NH4-N. The membrane-based DGTs are suitable for pH 3.5-8.5 and ionic strength ranges (0.0001-0.014 and 0.0003-0.012 mol L(-1) as NaCl for the AMI-7001 and CMI-7000 membrane, respectively) typical of most natural freshwaters...
November 14, 2016: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/27824186/evaluation-of-antibacterial-and-antifungal-compounds-for-selective-inhibition-of-denitrification-in-soils
#6
Shiva Ladan, Pierre-André Jacinthe
Nitrous oxide (N2O) is an atmospheric constituent implicated in climate warming and stratospheric ozone depletion. Both bacteria and fungi participate in N2O production, but information is lacking with regard to the relative contribution of bacterial and fungal denitrifiers to the denitrification process in agricultural soils. The selective inhibition (SI) technique is widely used to assess the contribution of different groups of microbes to soil processes, but success of the technique depends on the effectiveness of the inhibitors...
November 8, 2016: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/27819710/transparency-of-chemical-risk-assessment-data-under-reach
#7
Ellen Ingre-Khans, Marlene Ågerstrand, Anna Beronius, Christina Rudén
The REACH regulation requires EU manufacturers and importers of substances to register information on the hazard and risk of their substances with the European Chemicals Agency (ECHA). Risk management of the substances is based on the provided information. It is known that conclusions on hazard and risk are influenced by expert judgements as well as potential conflict of interests. Thus, it is important that hazard and risk assessments are transparent and can be evaluated by a third party. The aim of this study is to scrutinize the transparency, i...
November 7, 2016: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/27812561/dft-study-of-the-formation-mechanism-of-anthraquinone-from-the-reaction-of-no2-and-anthracene-on-nacl-clusters-the-role-of-nano3
#8
Chao Luo, Qiming Yu, Hongming Wang
Polycyclic aromatic hydrocarbons (PAHs) and oxygenated-PAHs are globally worrisome air pollutants because of their highly direct-acting mutagenicity and carcinogenicity. The formation of oxygenated-PAHs is of crucial importance for the prevention of their atmospheric pollution successfully. In this paper, the formation mechanism of oxygenated-PAHs from the heterogeneous reaction of NO2 with anthracene on the surface of NaCl was studied by density functional theory (DFT) calculations. At first, the various adsorption configurations of NO2 and N2O4 on NaCl were investigated...
November 4, 2016: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/27808329/exposure-of-children-to-bpa-through-dust-and-the-association-of-urinary-bpa-and-triclosan-with-oxidative-stress-in-guangzhou-china
#9
Yanshan Lv, Caiyan Rui, Yanyan Dai, Qihua Pang, Yanru Li, Ruifang Fan, Shaoyou Lu
Both bisphenol A (BPA) and triclosan (TCS) are phenolic compounds widely used in a variety of household applications. These compounds could be released into the environment, enter the human body and cause a series of potential health hazards. Children are sensitive and susceptible to these contaminants. To investigate the potential oxidative DNA damage from exposure to BPA and TCS, ninety six urine samples of children (aged 3-6) and 57 dust samples were collected from a kindergarten in Guangzhou, China. The concentrations of urinary BPA, TCS and 8-hydroxy-2'-deoxyguanosine (8-OHdG, a biomarker of oxidative DNA damage) in urine were determined using a liquid chromatography tandem mass spectrometer...
November 3, 2016: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/27796391/sulfate-formation-catalyzed-by-coal-fly-ash-mineral-dust-and-iron-iii-oxide-variable-influence-of-temperature-and-light
#10
Aruni Gankanda, Ellen M Coddens, Yaping Zhang, David M Cwiertny, Vicki H Grassian
Recent atmospheric field and modeling studies have highlighted a lack of understanding of the processes responsible for high levels of sulfate aerosol in the atmosphere, ultimately arising from a dearth of experimental data on such processes. Here we investigated the effect of temperature and simulated solar radiation on the catalytic oxidation of S(iv) to S(vi) (i.e., sulfite to sulfate) in aqueous suspensions of several metal-containing, atmospherically relevant particles including coal fly ash (FA), Arizona test dust (ATD) and an iron oxide (γ-Fe2O3)...
October 31, 2016: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/27782257/characteristics-and-determinants-of-ambient-volatile-organic-compounds-in-primary-schools
#11
Yu-Chun Wang, Chitsan Lin, Yu-Kai Lin, Ya-Fen Wang, Wei-Huang Weng, Yi-Ming Kuo
This study evaluates the effects of a sampling strategy that includes the sampling season, time period, ambient environment, and location on determining the concentrations and species of ambient volatile organic compounds (VOCs) that may affect children in primary schools. Air samples were collected from playgrounds in primary schools, with four sites near an oil refinery plant in Taoyuan and two sites in Zhongli (one site near a bus terminal and the other site in a suburban area) in Taiwan. The samples were obtained on eight occasions from August 2010 to June 2011...
October 26, 2016: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/27762408/a-review-of-stereochemical-implications-in-the-generation-of-secondary-organic-aerosol-from-isoprene-oxidation
#12
James M Cash, Mathew R Heal, Ben Langford, Julia Drewer
The atmospheric reactions leading to the generation of secondary organic aerosol (SOA) from the oxidation of isoprene are generally assumed to produce only racemic mixtures, but aspects of the chemical reactions suggest this may not be the case. In this review, the stereochemical outcomes of published isoprene-degradation mechanisms contributing to high amounts of SOA are evaluated. Despite evidence suggesting isoprene first-generation oxidation products do not contribute to SOA directly, this review suggests the stereochemistry of first-generation products may be important because their stereochemical configurations may be retained through to the second-generation products which form SOA...
October 20, 2016: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/27761530/spatial-assessment-of-soil-nitrogen-availability-and-varying-effects-of-related-main-soil-factors-on-soil-available-nitrogen
#13
Mingkai Qu, Weidong Li, Chuanrong Zhang, Biao Huang, Yongcun Zhao
To effectively understand the availability of soil nitrogen and assist in soil nitrogen control at the regional scale, it is essential to understand the accurate spatial distribution patterns of the three soil nitrogen parameters [i.e., total nitrogen (TN), available nitrogen (AN) and nitrogen availability ratio (NAR)] and explore the spatially varying influences of major impact factors on soil AN. Land use affects the spatial distributions of soil TN, AN and NAR (i.e., AN/TN). To explore the effects of different land use types and improve mapping accuracy, residual kriging with land use information and ordinary kriging (without land use information) were compared based on the sample data of soil TN and AN in Hanchuan county, China...
October 20, 2016: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/27740659/removal-of-heavy-metals-from-contaminated-soil-by-electrodialytic-remediation-enhanced-with-organic-acids
#14
Ouarda Merdoud, Claudio Cameselle, Mohamed Oualid Boulakradeche, Djamal Eddine Akretche
The soil from an industrial area in Algeria was contaminated with Cr (8370 mg kg(-1)), Ni (1135 mg kg(-1)) and zinc (1200 mg kg(-1)). The electrodialytic remediation of this soil was studied using citric acid and EDTA as facilitating agents. 0.1 M citric acid or EDTA was added directly to the soil before it was introduced in an electrodialytic cell in an attempt to enhance the heavy metal solubility in the interstitial fluid. The more acidic pH in the soil when citric acid was used as the facilitating agent was not enough to mobilize and remove the metals from the soil...
October 14, 2016: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/27731875/preliminary-assessment-of-the-potential-for-and-limitations-to-terrestrial-negative-emission-technologies-in-the-uk
#15
Pete Smith, R Stuart Haszeldine, Stephen M Smith
The aggregate technical potential for land-based negative emissions technologies (NETs) in the UK is estimated to be 12-49 Mt C eq. per year, representing around 8-32% of current emissions. The proportion of this potential that could be realized is limited by a number of cost, energy and environmental constraints which vary greatly between NETs.
October 12, 2016: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/27722628/triplet-state-dissolved-organic-matter-in-aquatic-photochemistry-reaction-mechanisms-substrate-scope-and-photophysical-properties
#16
Kristopher McNeill, Silvio Canonica
Excited triplet states of chromophoric dissolved organic matter ((3)CDOM*) play a major role among the reactive intermediates produced upon absorption of sunlight by surface waters. After more than two decades of research on the aquatic photochemistry of (3)CDOM*, the need for improving the knowledge about the photophysical and photochemical properties of these elusive reactive species remains considerable. This critical review examines the efforts to date to characterize (3)CDOM*. Information on (3)CDOM* relies mainly on the use of probe compounds because of the difficulties associated with directly observing (3)CDOM* using transient spectroscopic methods...
October 7, 2016: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/27722355/impacts-of-coal-ash-on-methylmercury-production-and-the-methylating-microbial-community-in-anaerobic-sediment-slurries
#17
Grace E Schwartz, Lauren K Redfern, Kaoru Ikuma, Claudia K Gunsch, Laura S Ruhl, Avner Vengosh, Heileen Hsu-Kim
Mercury (Hg) associated with coal ash is an environmental concern, particularly if the release of coal ash to the environment is associated with the conversion of inorganic Hg to methylmercury (MeHg), a bioaccumulative form of Hg that is produced by anaerobic microorganisms. In this study, sediment slurry microcosm experiments were performed to understand how spilled coal ash might influence MeHg production in anaerobic sediments of an aquatic ecosystem. Two coal ash types were used: (1) a weathered coal ash; and (2) a freshly collected, unweathered fly ash that was relatively enriched in sulfate and Hg compared to the weathered ash...
October 5, 2016: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/27711837/cyanotoxin-degradation-activity-and-mlr-gene-expression-profiles-of-a-sphingopyxis-sp-isolated-from-lake-champlain-canada
#18
Ehsan Maghsoudi, Nathalie Fortin, Charles Greer, Christine Maynard, Antoine Pagé, Sung Vo Duy, Sébastien Sauvé, Michèle Prévost, Sarah Dorner
A bacterium capable of degrading five microcystin (MC) variants, microcystin-LR, YR, LY, LW and LF at an initial total concentration of 50 μg l(-1) in less than 16 hours was isolated from Missisquoi Bay, in the south of Quebec, Canada. Phylogenetic analysis of the 16S rRNA gene sequence identified the bacterium as Sphingopyxis sp., designated strain MB-E. It was shown that microcystin biodegradation activity was reduced at acidic and basic pH values. Even though no biodegradation occurred at pH values of 5...
October 3, 2016: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/27711832/transformation-of-chlorpyrifos-and-chlorpyrifos-methyl-in-prairie-pothole-pore-waters
#19
Rachel M Adams, Brandon C McAdams, William A Arnold, Yu-Ping Chin
Non-point source pesticide pollution is a concern for wetlands in the prairie pothole region (PPR). Recent studies have demonstrated that reduced sulfur species (e.g., bisulfide and polysulfides) in PPR wetland pore waters directly undergo reactions with chloroacetanilide and dinitroaniline compounds. In this paper, the abiotic transformation of two organophosphate compounds, chlorpyrifos and chlorpyrifos-methyl, was studied in PPR wetland pore waters. Chlorpyrifos-methyl reacted significantly faster (up to 4 times) in pore water with reduced sulfur species relative to hydrolysis...
September 30, 2016: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/27722356/oligomeric-models-for-estimation-of-polydimethylsiloxane-water-partition-ratios-with-cosmo-rs-theory-impact-of-the-combinatorial-term-on-absolute-error
#20
J Mark Parnis, Donald Mackay
A series of 12 oligomeric models for polydimethylsiloxane (PDMS) were evaluated for their effectiveness in estimating the PDMS-water partition ratio, KPDMS-w. Models ranging in size and complexity from the -Si(CH3)2-O- model previously published by Goss in 2011 to octadeca-methyloctasiloxane (CH3-(Si(CH3)2-O-)8CH3) were assessed based on their RMS error with 253 experimental measurements of log KPDMS-w from six published works. The lowest RMS error for log KPDMS-w (0.40 in log K) was obtained with the cyclic oligomer, decamethyl-cyclo-penta-siloxane (D5), (-Si(CH3)2-O-)5, with the mixing-entropy associated combinatorial term included in the chemical potential calculation...
September 14, 2016: Environmental Science. Processes & Impacts
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