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Environmental Science & Technology

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https://read.qxmd.com/read/30776221/conserved-microbial-toxicity-responses-for-acute-and-chronic-silver-nanoparticle-treatments-in-wetland-mesocosms
#1
Christopher S Ward, Jin-Fen Pan, Benjamin P Colman, Zhao Wang, Carley A Gwin, Tiffany C Williams, Abby Ardis, Claudia K Gunsch, Dana E Hunt
Most studies of bacterial exposure to environmental contaminants focuse on acute treatments; yet, the impacts of single, high-dose exposures on microbial communities may not readily be extended to the more likely scenario of chronic, low-dose contaminant exposures. Here, in a year-long, wetland mesocosm experiment, we compared microbial community responses to pulse (single 450 mg dose of silver) and chronic (weekly 8.7 mg doses of silver for one year) silver nanoparticle (Ag0NP) treatments, as well as a chronic treatment of "aged" sulfidized silver nanoparticles (Ag2S NPs)...
February 18, 2019: Environmental Science & Technology
https://read.qxmd.com/read/30776220/phenology-of-phytoplankton-blooms-in-a-trophic-lake-observed-from-long-term-modis-data
#2
Kun Shi, Yunlin Zhang, Yibo Zhang, Na Li, Boqiang Qin, Guangwei Zhu, Yongqiang Zhou
Phytoplankton phenology critically affects elements biogeochemical cycles, ecosystem structure, and productivity. However, our understanding about the phenological process and driving mechanism is still very limited due to the shortage of long-term observation data. We used all available daily MODIS-Aqua data from 2003 to 2017 to determine bloom start dates (BSDs) in a typical trophic lake (Lake Taihu) and investigate how phytoplankton BSDs respond to climate change and environmental factors. The results indicate that BSDs have advanced 29...
February 18, 2019: Environmental Science & Technology
https://read.qxmd.com/read/30776217/microbial-chromate-reduction-coupled-to-anaerobic-oxidation-of-elemental-sulfur-or-zerovalent-iron
#3
Jiaxin Shi, Baogang Zhang, Rui Qiu, Chunyu Lai, Yufeng Jiang, Chao He, Jianhua Guo
Chromate (Cr(VI)), as one of ubiquitous contaminants in groundwater, has posed a major threat to public health and ecological environment. Although various electron donors (e.g., organic carbon, hydrogen and methane) have been proposed to drive chromate removal from contaminated water, little is known for microbial chromate reduction coupled to elemental sulfur (S(0)) or zerovalent iron (Fe(0)) oxidation. This study demonstrated chromate could be biologically reduced by using S(0) or Fe(0) as inorganic electron donor...
February 18, 2019: Environmental Science & Technology
https://read.qxmd.com/read/30768259/breakdown-products-from-perfluorinated-alkyl-substances-pfas-degradation-in-a-plasma-based-water-treatment-process
#4
Raj Kamal Singh, Sujan Fernando, Sadjad Fakouri Baygi, Nicholas Multari, Selma Mededovic Thagard, Thomas M Holsen
Byproducts produced when treating perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in water using a plasma treatment process intentionally operated to treat these compounds slowly to allow for byproduct accumulation were quantified. Several linear chain perfluoroalkyl carboxylic acids (PFCAs) (C4 to C7) were identified as byproducts of both PFOA and PFOS treatment. PFOA, perfluorohexane sulfonate (PFHxS) and perfluorobutane sulfonate (PFBS) were also found to be byproducts from PFOS degradation...
February 15, 2019: Environmental Science & Technology
https://read.qxmd.com/read/30768252/making-acute-tests-more-ecologically-relevant-cadmium-bioaccumulation-and-toxicity-in-an-estuarine-clam-under-various-salinities-modeled-in-a-toxicokinetic-toxicodynamic-framework
#5
Qiao-Guo Tan, Shunhua Lu, Rong Chen, Jinghe Peng
Salinity has considerable effects on the toxicity of metals in estuarine waters. The effects of salinity are manifold, making it difficult to summarize for risk assessments. In this study, we separated and quantified the multiple effects of salinity on cadmium (Cd) in a toxicokinetic-toxicodynamic framework. The estuarine clam, Potamocorbula laevis, was used as a model organism. Cd bioaccumulation was measured using a stable-isotope-tracer technique; in parallel, toxicity tests were conducted. With the increase of salinity from 5 to 30, Cd uptake decreased monotonically...
February 15, 2019: Environmental Science & Technology
https://read.qxmd.com/read/30768244/carbon-fiber-based-flow-through-electrode-system-fes-for-water-disinfection-via-direct-oxidation-mechanism-with-a-sequential-reduction-oxidation-process
#6
Hai Liu, Xin-Ye Ni, Zheng-Yang Huo, Lu Peng, Guo-Qiang Li, Chun Wang, Yin-Hu Wu, Hong-Ying Hu
Flow-through configuration for electrochemical disinfection is considered as a promising approach to minimize the formation of toxic byproducts and energy consumption via the enhanced convective mass transport as compared with conventional flow-by one. Under this hydrodynamic condition, it is essential to ascertain the effect of sequential electro-redox processes with the cathode/anode then anode/cathode arrangements on disinfection performance. Here, carbon fiber felt (CFF) was utilized to construct two flow-through electrode systems (FESs) with sequential reduction-oxidation (cathode-anode) or oxidation-reduction (anode-cathode) processes to systematically compare their disinfection performance towards a model Escherichia coli (E...
February 15, 2019: Environmental Science & Technology
https://read.qxmd.com/read/30767516/the-fate-of-zn-in-agricultural-soils-a-stable-isotope-approach-to-anthropogenic-impact-soil-formation-and-soil-plant-cycling
#7
Martin Imseng, Matthias Wiggenhauser, Michael Müller, Armin Keller, Emmanuel Frossard, Wolfgang Wilcke, Moritz Bigalke
The supplementation of Zn to farm animal feed and the excretion via manure leads to an unintended Zn input to agricultural systems, which might compromise the long-term soil fertility. The Zn fluxes at three grassland sites in Switzerland were determined by a detailed analysis of relevant inputs (atmospheric deposition, manure, weathering) and outputs (seepage water, biomass harvest) during one hydrological year. The most important Zn input occurred through animal manure (1,076 to 1,857 g ha-1 yr-1) and Zn mass balances revealed net Zn accumulations (456 to 1,478 g ha-1 yr-1)...
February 15, 2019: Environmental Science & Technology
https://read.qxmd.com/read/30767514/mineral-surfaces-as-agents-of-environmental-proteolysis-mechanisms-and-controls
#8
Stephany S Chacon, Patrick N Reardon, Christopher James Burgess, Samuel Owen Purvine, Rosalie K Chu, Therese Rw Clauss, Eric D Walter, David D Myrold, Nancy Washton, Markus Kleber
We investigated the extent to which contact with mineral surfaces affected the molecular integrity of a model protein, with an emphasis on identifying the mechanisms (hydrolysis, oxidation) and conditions leading to protein alteration. To this end, we studied the ability of four mineral surface archetypes (negatively charged, positively charged, neutral, redox-active) to abiotically fragment a well-characterized protein (GB1) as a function of pH and contact time. GB1 was exposed to the soil minerals montmorillonite, goethite, kaolinite, and birnessite at pH 5 and pH 7 for 1, 8, 24, and 168 hours and the supernatant was screened for peptide fragments using Tandem Mass Spectrometry...
February 15, 2019: Environmental Science & Technology
https://read.qxmd.com/read/30715861/oxidation-of-sulfonamide-antibiotics-of-six-membered-heterocyclic-moiety-by-ferrate-vi-kinetics-and-mechanistic-insight-into-so-2-extrusion
#9
Mingbao Feng, J Clayton Baum, Nasri Nesnas, Yunho Lee, Ching-Hua Huang, Virender K Sharma
This work presents ferrate(VI) (FeVI O4 2- , FeVI ) oxidation of a wide range of sulfonamide antibiotics (SAs) containing five- and six-membered heterocyclic moieties ( R) in their molecular structures. Kinetics measurements of the reactions between FeVI and SAs at different pH (6.5-10.0) give species-specific second-order rate constants, k5 and k6 of the reactions of protonated FeVI (HFeO4 - ) and unprotonated FeVI (FeVI O4 2- ) with protonated SAs (HX), respectively. The values of k5 varied from (1.2 ± 0...
February 15, 2019: Environmental Science & Technology
https://read.qxmd.com/read/30763514/evaluation-of-a-pilot-anaerobic-secondary-effluent-for-potable-reuse-impact-of-different-disinfection-schemes-on-organic-fouling-of-ro-membranes-and-dbp-formation
#10
Aleksandra Szczuka, Juliana Berglund-Brown, Hannah Chen, Amanda Quay, William A Mitch
Anaerobic biological secondary treatment has the potential to substantially reduce the energy cost and footprint of wastewater treatment. However, for utilities seeking to meet future water demand through potable reuse, the compatibility of anaerobically-treated secondary effluent with potable reuse trains has not been evaluated. This study characterized the effects of different combinations of chloramines, ozone and biological activated carbon (BAC), applied as pretreatments to mitigate organic chemical fouling of reverse osmosis (RO) membranes and the production of 43 disinfection byproducts (DBPs)...
February 14, 2019: Environmental Science & Technology
https://read.qxmd.com/read/30762346/hydrodynamic-versus-surface-interaction-impacts-of-roughness-in-closing-the-gap-between-favorable-and-unfavorable-colloid-transport-conditions
#11
Anna Rasmuson, Kurt VanNess, Cesar Ron, William P Johnson
Recent experiments revealed that roughness decreases the gap in colloid attachment between favorable (repulsion absent) and unfavorable (repulsion present) conditions through a combination of hydrodynamic slip and surface interactions with asperities. Hydrodynamic slip was calibrated to experimentally-observed tangential colloid velocities, demonstrating that slip length was equal to maximum asperity relief, thereby providing a functional relationship between slip and roughness metrics. Incorporation of the slip length in mechanistic particle trajectory simulations yielded the observed modest decrease in attachment over rough surfaces under favorable conditions, with the observed decreased attachment being due to reduced colloid delivery rather than decreased attraction...
February 14, 2019: Environmental Science & Technology
https://read.qxmd.com/read/30761900/legacy-and-currently-used-organic-contaminants-in-human-hair-and-hand-wipes-of-female-e-waste-dismantling-workers-and-workplace-dust-in-south-china
#12
Lin Qiao, Xiaobo Zheng, Jing Zheng, She-Jun Chen, Changqin Zhong, Jinghua Chen, Zhong-Yi Yang, Bi-Xian Xian Mai
Legacy organic contaminants, such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), and several currently used organic contaminants, such as novel brominated retardants (NBFRs), organophosphate flame retardants (OPFRs), and Dechlorane Plus (DPs), were measured in the segmented hair and hand wipes of e-waste dismantling workers and in the dust from their working place in an e-waste recycling site in South China to assess the accumulation and sources of organic contaminants in the hair shaft...
February 14, 2019: Environmental Science & Technology
https://read.qxmd.com/read/30758964/polyvinylchloride-microplastics-affect-methane-production-from-the-anaerobic-digestion-of-waste-activated-sludge-through-leaching-toxic-bisphenol-a
#13
Wei Wei, Qi-Su Huang, Jing Sun, Jun-Yue Wang, Shu-Lin Wu, Bing-Jie Ni
The retention of polyvinylchloride (PVC) microplastics in sewage sludge during wastewater treatment raises concerns recently. However, the effects of PVC microplastics on methane production from anaerobic digestion of waste activated sludge (WAS) have never been documented. In this work, the effects of PVC microplastics (1 mm, 10-60 particles/g TS) on anaerobic methane production from WAS were investigated. The presence of 10 particles/g TS of PVC microplastics significantly (P = 0.041) increased methane production by 5...
February 13, 2019: Environmental Science & Technology
https://read.qxmd.com/read/30758963/spatially-explicit-large-scale-environmental-risk-assessment-of-pharmaceuticals-in-surface-water-in-china
#14
Ying Zhu, Jason R Snape, Kevin C Jones, Andrew J Sweetman
With improving health care and an aging population, the consumption of human pharmaceuticals in China has been increasing dramatically. Environmental risks posed by many active pharmaceutical ingredients (APIs) are still unknown. This study used a spatially-explicit dilution-factor methodology to model predicted environmental concentrations (PECs) of 11 human-use APIs in surface water for a preliminary environmental risk assessment (ERA). Median PECs in surface water across China range between 0.01-8.0×103 ng/L for the different APIs, under a moderate patient use scenario...
February 13, 2019: Environmental Science & Technology
https://read.qxmd.com/read/30758954/flow-electrode-cdi-removes-the-uncharged-ca-uo2-co3-ternary-complex-from-brackish-potable-groundwater-complex-dissociation-transport-and-sorption
#15
Jinxing Ma, Yumeng Zhang, Richard N Collins, Sergey Tsarev, Noboru Aoyagi, Andrew S Kinsela, Adele M Jones, T David Waite
Unacceptably high uranium concentrations in decentralized and remote potable groundwater resources, especially those of high hardness (e.g. high Ca2+, Mg2+ and CO32- concentrations), are a common worldwide problem. The complexation of alkali earth metals, carbonate and uranium(VI) results in the formation of thermodynamically stable ternary aqueous species that are predominantly neutrally-charged (e.g. Ca2(UO2)(CO3)30). The removal of the uncharged (non-adsorbing) complexes is a problematic issue for many water treatment technologies...
February 13, 2019: Environmental Science & Technology
https://read.qxmd.com/read/30758207/electrochemical-analysis-of-changes-in-iron-oxide-reducibility-during-abiotic-ferrihydrite-transformation-into-goethite-and-magnetite
#16
Meret Aeppli, Ralf Kaegi, Ruben Kretzschmar, Andreas Voegelin, Thomas B Hofstetter, Michael Sander
Electron transfer to ferric iron in (oxyhydr-)oxides (hereafter iron oxides) is a critical step in many processes that are central to the biogeochemical cycling of elements and to contaminant dynamics. Understanding these processes requires analytical approaches that allow for characterizing the reactivity of iron oxides towards reduction under thermodynamically controlled conditions. Here, we used mediated electrochemical reduction (MER) to follow changes in iron oxide reduction extents and rates during abiotic ferrous iron-induced transformation of six-line ferrihydrite...
February 13, 2019: Environmental Science & Technology
https://read.qxmd.com/read/30758198/evaluating-the-performance-of-micro-encapsulated-co2-sorbents-during-co2-absorption-and-regeneration-cycling
#17
Jennifer M Knipe, Kathya P Chavez, Katherine M Hornbostel, Matthew A Worthington, Du T Nguyen, Congwang Ye, William L Bourcier, Sarah E Baker, Joan Frances Brennecke, Joshuah K Stolaroff
We encapsulated six solvents with novel physical and chemical properties for CO2 sorption within gas-permeable polymer shells, creating Micro-Encapsulated CO2 Sorbents (MECS), to improve the CO2 absorption kinetics and handling of the solvents for post-combustion CO2 capture from flue gas. The solvents were sodium carbonate (Na2CO3) solution, uncatalyzed and with two different promoters, two ionic liquid (IL) solvents, and one CO2-binding organic liquid (CO2BOL). We subjected each of the six MECS to multiple CO2 absorption and regeneration cycles and measured the working CO2 absorption capacity as a function of time to identify promising candidate MECS for large-scale carbon capture...
February 13, 2019: Environmental Science & Technology
https://read.qxmd.com/read/30758193/the-impact-of-natural-variation-of-oh-radical-demand-of-drinking-water-sources-on-the-optimum-operation-of-the-uv-h2o2-process
#18
Minhwan Kwon, Seonbaek Kim, Youmi Jung, Tae-Mun Hwang, Mihaela Stefan, Joon-Wun Kang
Hydroxyl radical (•OH) water demand is a key parameter which impacts the design and operation of UV/H2O2 process in water remediation projects. Long-term monitoring of the •OH water demand in water sources used for drinking water production indicated significant seasonal variations of this parameter (1.59×10<sup>4 to 4.98×10<sup>4 s-1), which coincided with the occurrence of algal blooming events. Pilot-scale tests at a drinking water treatment plant confirmed that the UV/H2O2 process performance for contaminant removal is predictable when the •OH water demand is accurately determined through a validated experimental method...
February 13, 2019: Environmental Science & Technology
https://read.qxmd.com/read/30758190/triplet-state-photochemistry-of-dissolved-organic-matter-triplet-state-energy-distribution-and-surface-electric-charge-conditions
#19
Huaxi Zhou, Shuwen Yan, Lushi Lian, Weihua Song
Excited triplet states of chromophoric dissolved organic matter (3CDOM*) are highly reactive species in sunlit surface waters and play a critical role in reactive oxygen species (ROS) formation and pollutant attenuation. In the present study, a series of chemical probes, including sorbic acid, sorbic alcohol, sorbic amine, trimethylphenol, and furfuryl alcohol, were employed to quantitatively determine 3CDOM* and 1O2 in various organic matters. Using a high concentration of sorbic alcohol as high-energy triplet states quencher, 3CDOM* can be firstly distinguished as high-energy triplet states (>250 kJ mol-1) and low-energy triplet states (<250 kJ mol-1)...
February 13, 2019: Environmental Science & Technology
https://read.qxmd.com/read/30754970/spatial-and-temporal-variability-in-attenuation-of-polar-organic-micropollutants-in-an-urban-lowland-stream
#20
Anna Jaeger, Malte Posselt, Andrea Betterle, Jonas Schaper, Jonas Mechelke, Claudia Coll, Jörg Lewandowski
Contamination of rivers by trace organic compounds (TrOCs) poses a risk for aquatic ecosystems and drinking water quality. Spatially- and temporally-varying environmental conditions are expected to play a major role in controlling in-stream attenuation of TrOCs. This variability is rarely captured by in situ studies of TrOC attenuation. Instead, snap-shots or time-weighted average conditions and corresponding attenuation rates are reported. The present work sought to investigate this variability and factors controlling it by analysis of 24 TrOCs over a 4...
February 13, 2019: Environmental Science & Technology
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