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Environmental chemistry

Julien Arsenault, Julie Talbot, Tim R Moore
Pools are common in northern peatlands but studies have seldom focused on their nutrient biogeochemistry, especially in relation to their morphological characteristics and through seasons. We determined the environmental characteristics controlling carbon (C), nitrogen (N) and phosphorus (P) biogeochemistry in pools and assessed their evolution over the course of the 2016 growing season in a subboreal ombrotrophic peatland of eastern Canada. We showed that water chemistry variations in 62 pools were significantly explained by depth (81...
March 12, 2018: Science of the Total Environment
Debra A Davis, Sparkle L Malone, Charles R Lovell
Drought has many consequences in the tidally dominated Spartina sp. salt marshes of the southeastern US; including major dieback events, changes in sediment chemistry and obvious changes in the landscape. These coastal systems tend to be highly productive, yet many salt marshes are also nitrogen limited and depend on plant associated diazotrophs as their source of 'new' nitrogen. A 4-year study was conducted to investigate the structure and composition of the rhizosphere diazotroph assemblages associated with 5 distinct plant zones in one such salt marsh...
March 15, 2018: Microorganisms
Nazario Martin, Alicia López-Andarias, Javier López-Andarias, Carmen Atienza, Francisco J Chichón, José L Carrascosa
Supramolecular chemistry has evolved from the traditional focus on thermodynamic on-pathways to the complex study of kinetic off-pathways, which are strongly dependent of the environmental conditions. Moreover, the control over pathway complexity allows obtaining nanostructures that are inaccessible through spontaneous thermodynamic processes. Here, we present a family of peptide-based π-extended tetrathiafulvalene (exTTF) molecules which show two self-assembly pathways leading to two distinct J-aggregates, namely metastable (M) and thermodynamic (T), with different spectroscopic, chiroptical and electrochemical behavior...
March 14, 2018: Chemistry: a European Journal
Emmanuel E Psykarakis, Elli Chatzopoulou, Thanasis Gimisis
A number of environmental pollutants and endogenous oxidation agents form 1-(2-deoxy-β-d-ribofuranosyl)-5-hydroxy-5-methylhydantoin (HydT), an important DNA lesion resulting from thymidine oxidation. In this paper, two intermediates, postulated in the formation of HydT, have been characterised for the first time. The first, N1 -formyl-N3 -pyruvoylurea intermediate, was produced by the ozonolysis reaction of 2',3',5'-tri-O-acetylribo-, 3',5'-di-O-TBS- and N3 ,O3' ,O5 -tribenzyl-protected thymidines and was shown to produce, upon decomposition and depending on the protecting group and the conditions, HydT alone, or together with protected-β-d-ribofuranosyl-N1 -formylurea and formamide products...
March 14, 2018: Organic & Biomolecular Chemistry
Ana B Silva, Ana S Bastos, Celine I L Justino, João P da Costa, Armando C Duarte, Teresa A P Rocha-Santos
Microplastics can be present in the environment as manufactured microplastics (known as primary microplastics) or resulting from the continuous weathering of plastic litter, which yields progressively smaller plastic fragments (known as secondary microplastics). Herein, we discuss the numerous issues associated with the analysis of microplastics, and to a less extent of nanoplastics, in environmental samples (water, sediments, and biological tissues), from their sampling and sample handling to their identification and quantification...
August 9, 2018: Analytica Chimica Acta
Robin S Sleith, John D Wehr, Kenneth G Karol
Forecasting changes in the distributions of macrophytes is essential to understanding how aquatic ecosystems will respond to climate and environmental changes. Previous work in aquatic ecosystems has used climate data at large scales and chemistry data at small scales; the consequence of using these different data types has not been evaluated. This study combines a survey of macrophyte diversity and water chemistry measurements at a large regional scale to demonstrate the feasibility and necessity of including ecological measurements, in addition to climate data, in species distribution models of aquatic macrophytes...
March 2018: Ecology and Evolution
Megan Suzanne Claflin, Paul J Ziemann
Substantial amounts of gas- and particle-phase organic nitrates have been reported in field studies of atmospheric chemistry conducted around the world, and it has been proposed that a significant fraction of these may be formed from the nighttime reaction of monoterpenes with NO3 radicals. In the study presented here, β-pinene (a major global monoterpene emission) was reacted with NO3 radicals in an environmental chamber and the molecular and functional group composition of the resulting secondary organic aerosol (SOA) was determined using a variety of methods...
March 12, 2018: Journal of Physical Chemistry. A
Kelsey Craig
Sulfur dioxide (SO2 ) is an atmospheric pollutant that is moderately persistent in the atmosphere and highly water soluble. When applied as a pesticide, SO2 may be transported, deposited, or transformed in various chemical reactions. SO2 participates in the sulfur biogeochemical cycle, which involves complex reactions of sulfur-containing compounds between abiotic and biotic components of ecosystems. The main degradation route of SO2 is atmospheric oxidation, and sulfur oxides may undergo long-distance transport prior to removal from the atmosphere by wet or dry deposition...
March 11, 2018: Reviews of Environmental Contamination and Toxicology
Deepak Bhandari, Brett A Bowman, Anish B Patel, David M Chambers, Víctor R De Jesús, Benjamin C Blount
This work describes a quantitative high-throughput analytical method for the simultaneous measurement of small aliphatic nitrogenous biomarkers, i.e., 1,6-hexamethylenediamine (HDA), isophoronediamine (IPDA), β-methylamino-l-alanine (BMAA), and trimethylamine N-oxide (TMAO), in human urine. Urinary aliphatic diamines, HDA and IPDA, are potential biomarkers of environmental exposure to their corresponding diisocyanates. Urinary BMAA forms as a result of human exposure to blue-green algae contaminated food. And, TMAO is excreted in urine due to the consumption of carnitine- and choline-rich diets...
March 2, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Nicholas Dusek, Austin J Hewitt, Kaycie N Schmidt, Peter W Bergholz
E. coli are deposited into soil with feces and exhibit subsequent population decline with concomitant environmental selection. Environmentally persistent strains exhibit longer survival times during this selection process and some strains have adapted to soil and sediments. A georeferenced collection of E. coli isolates was developed comprising 3,329 isolates from 1,428 soil samples that were collected from a landscape spanning the transition from the grasslands to the eastern deciduous forest biomes. The isolate collection and sample database were analyzed together to discover how land cover, site characteristics and soil chemistry influence the prevalence of cultivable E...
March 9, 2018: Applied and Environmental Microbiology
Sigalit Gura, Anamary Tarifa, Jerome Mulloor, Michelle N Torres, José R Almirall
A novel phenyl modified PDMS (PhPDMS) sol-gel adsorption phase was developed for use with the capillary microextraction of volatiles (CMV) device, and determined to provide significant enhancement in BTEX recoveries when sampling trace (ng) amounts of these volatiles at ambient conditions. The previously reported reusable PDMS-CMV device has been demonstrated to rapidly and efficiently extract target compound's vapors in forensic and environmental applications. An improved recovery for VOCs was achieved with a cryofocusing system while extracting at -10 ° C, but it was found to be impractical for field sampling...
July 19, 2018: Analytica Chimica Acta
Guotao Peng, Robbie Martin, Stephen Dearth, Xiaocun Sun, Gregory L Boyer, Shawn Campagna, Sijie Lin, Steven W Wilhelm
Freshwater cyanobacterial blooms are regularly formed by Microcystis spp., which are well-known producers of the hepatotoxin microcystin. The environmental factors that regulate microcystin synthesis remain unclear. We used reverse transcription-quantitative PCR (RT-qPCR), metabolomics, and toxin profiling (both by LC-MS) to measure the response of Microcystis aeruginosa NIES-843 to nitrogen (N) concentration, N chemistry (nitrate vs. urea), and a range of seasonally-relevant temperatures. Growth rates at lower temperatures were slower but resulted in increased cellular microcystin content (quota), and at these lower temperatures, N concentration had no effect on toxin production...
March 9, 2018: Environmental Science & Technology
Maggie R Wagner, Thomas Mitchell-Olds
Phenotypic plasticity is thought to impact evolutionary trajectories by shifting trait values in a direction that is either favored by natural selection ("adaptive plasticity") or disfavored ("nonadaptive" plasticity). However, it is unclear how commonly each of these types of plasticity occurs in natural populations. To answer this question, we measured glucosinolate defensive chemistry and reproductive fitness in over 1,500 individuals of the wild perennial mustard Boechera stricta, planted in four common gardens across central Idaho, USA...
March 9, 2018: Evolution; International Journal of Organic Evolution
Chuanrui Chen, Emil Karshalev, Jianguo Guan, Joseph Wang
The new capabilities and functionalities of synthetic micro/nanomotors open up considerable opportunities for diverse environmental and biomedical applications. Water-powered micromachines are particularly attractive for realizing many of these applications. Magnesium-based motors directly use water as fuel to generate hydrogen bubbles for their propulsion, eliminating the requirement of common toxic fuels. This Review highlights the development of new Mg-based micromotors and discusses the chemistry that makes it extremely attractive for micromotor applications...
March 9, 2018: Small
Kamel Mansouri, Chris M Grulke, Richard S Judson, Antony J Williams
The collection of chemical structure information and associated experimental data for quantitative structure-activity/property relationship (QSAR/QSPR) modeling is facilitated by an increasing number of public databases containing large amounts of useful data. However, the performance of QSAR models highly depends on the quality of the data and modeling methodology used. This study aims to develop robust QSAR/QSPR models for chemical properties of environmental interest that can be used for regulatory purposes...
March 8, 2018: Journal of Cheminformatics
Jenna L Luek, Mourad Harir, Philippe Schmitt-Kopplin, Paula J Mouser, Michael Gonsior
The chemistry of hydraulic fracturing fluids and wastewaters is complex and is known to vary by operator, geologic formation, and fluid age. A time series of hydraulic fracturing fluids, flowback fluids, and produced waters was collected from two adjacent Marcellus Shale gas wells for organic chemical composition analyses using ultrahigh resolution mass spectrometry. Hierarchical clustering was used to compare and extract ions related to different fluid ages and many halogenated organic molecular ions were identified in flowback fluids and early produced waters based on exact mass...
March 2, 2018: Water Research
Snehali Mali, Sachin Shinde, Shashikant Damte, Suresh Patil
Without using any toxic or hazardous reagent, ligand, acid, transition metal catalyst, additives/promoters and organic solvent, green Knoevenagel condensation and tandem Knoevenagel-Michael reactions have been successfully carried out by using chickpea leaf exudates as a naturally sourced Bronsted acid type bio-catalyst. The reaction proceeds in neat chickpea leaf exudates at room temperature in aqueous conditions in very short reaction times, and therefore, it is an evergreen and environmentally sound alternative to the existing protocols for benzopyran synthesis...
February 2018: Royal Society Open Science
Ioannis A Katsoyiannis, Dimitra Voutsa
No abstract text is available yet for this article.
March 7, 2018: Environmental Science and Pollution Research International
Nicolas Sauermann, Ruhuai Mei, Lutz Ackermann
Syntheses of substituted anilines primarily rely on palladium-catalyzed coupling chemistry with prefunctionalized aryl electrophiles. While oxidative aminations have emerged as powerful alternatives, they largely produce undesired metal-containing by-products in stoichiometric quantities. In contrast, herein we describe the unprecedented electrochemical C-H amination by cobalt-catalyzed C-H activation. The environmentally-benign electrocatalysis avoids stoichiometric metal oxidants, can be conducted under ambient air and employs a biomass-derived, renewable solvent for sustainable aminations in an atom- and step-economical manner with H2 as the sole byproduct...
March 6, 2018: Angewandte Chemie
Eric McGivney, Kayleigh Elizabeth Jones, Bandrea Weber, Ann Margaret Valentine, Jeanne M Vanbriesen, Kelvin B Gregory
Quorum sensing (QS) regulates important bacterial behaviors such as virulent protein production and biofilm formation. QS requires that molecular signals are exchanged between cells, extracellularly, where environmental conditions influence signal stability. In this work, we present a novel complexation between metal cations (Ag+ and Cu2+ ) and a QS autoinducer signal, N-hexanoyl-homoserine lactone (HHL). The molecular interactions were investigated using mass spectrometry, attenuated total reflectance-Fourier transform infrared spectroscopy, and computational simulations...
March 6, 2018: ACS Chemical Biology
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