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1.
J Environ Qual ; 49(2): 256-267, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33016414

RESUMO

Fertilizer N losses from agricultural systems have economic and environmental implications. Soil amendment with high C materials, such as coal char, may mitigate N losses. Char, a coal combustion residue, obtained from a sugar factory in Scottsbluff, NE, contained 29% C by weight. A 30-d laboratory study was conducted to evaluate the effects of char addition on N losses via nitrous oxide (N2 O) emission, ammonia (NH3 ) volatilization, and nitrate (NO3 -N) leaching from fertilized loam and sandy loam soils. Char was applied at five different rates (0, 6.7, 10.1, 13.4, and 26.8 Mg C ha-1 ; char measured in C equivalent) to soils fertilized with urea ammonium nitrate (UAN) at 200 kg N ha-1 . In addition, there were two negative-UAN control treatments: no char (no UAN) and char at 26.8 Mg C ha-1 (no UAN). Treatment applied at 6.7 and 10.1 Mg C ha-1 in fertilized sandy loam reduced NH3 volatilization by 26-37% and at 6.7, 10.1, and 13.4 Mg C ha-1 in fertilized loam soils by 24% compared with no char application. Nitrous oxide emissions and NO3 -N leaching losses were greater in fertilized compared with unfertilized soil, but there was no effect of char amendment on these losses. Because NO3 -N leaching loss was greater in sandy loam than in loam, soil residual N was twofold higher in loam than in sandy loam. This study suggests that adding coal char at optimal rates may reduce agricultural reactive N to the atmosphere by decreasing NH3 volatilization from fertilized soils.


Assuntos
Amônia , Solo , Carvão Mineral , Fertilizantes , Volatilização
2.
J Environ Qual ; 49(5): 1445-1452, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33016443

RESUMO

Volatilization of NH3 following urea application or livestock urine deposition can result in significant loss of N to the environment. Urea hydrolysis to NH4 + results in an increase in pH, which in turn promotes transformation of NH4 + to NH3 . Accurately predicting changes in soil pH following urea (or urine) application will allow successful simulation of NH3 volatilization. The magnitude of the pH change depends on the soil's pH buffering capacity (pHBC). However, as actual pHBC values are not generally available, pHBC proxies (e.g., cation exchange capacity) have been used in modeling studies. In a 34-d laboratory incubation study, we measured soil pH and mineral N (NH4 + and NO3 - ) following a large application of urea (800 mg N kg-1 soil) to four soils with a range of pHBC values. In a second incubation, pH changes and mineral N dynamics were monitored in soil treated with sheep urine (773 mg N kg-1 soil) in the absence and presence of the nitrification inhibitor dicyandiamide. In both incubations, pH changes associated with urea hydrolysis and subsequent nitrification of NH4 + were predicted well using measured pHBC data. Our results confirmed that pHBC is base-type dependent (values greater when measured using KOH than NH4 OH). Soil pHBC is easily measured, and the use of a measured value (determined using NH4 OH) can improve model simulations of pH in the field and, potentially, lead to improved estimates of NH3 loss from animal-deposited urine patches and urea-treated soil.


Assuntos
Solo , Ureia , Animais , Concentração de Íons de Hidrogênio , Nitrificação , Ovinos , Volatilização
3.
Acta Odontol Latinoam ; 33(2): 135-142, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32920616

RESUMO

This study evaluated the influence of the mode and time of solvent evaporation on the tensile strength (TS), flexural strength (FS) and elastic modulus (EM) of two adhesive systems: Scotchbond Multipurpose (SBMP) and Clearfil SE (CSEB). For this purpose, rectangular samples (2x1x7 mm) were prepared with 10 µL of primer and the solvents were evaporated with air spray at (23±1) ºC, (40±1) ºC and negative control (without spray). For each temperature, the times of 5, 20, 30, and 60 seconds were investigated. The statistical results showed that evaporation at 40±1ºC resulted in better EM for the two adhesives tested and all the evaporation times evaluated. However, there were no significant differences between the times and modes of evaporation for TS. The results of this study indicate that evaporation at a temperature of (40±1) °C could improve the elastic modulus of both adhesives tested, regardless of the evaporating time.


Assuntos
Adesivos/química , Cimentos Dentários/química , Adesivos Dentinários/química , Solventes/farmacologia , Resistência à Tração , Dessecação , Humanos , Teste de Materiais , Volatilização
4.
Chemosphere ; 254: 126890, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957290

RESUMO

Chlorine disinfection inactivates pathogens in drinking water, but meanwhile it causes the formation of halogenated disinfection byproducts (DBPs), which may induce adverse health effects. Humans are unavoidably exposed to halogenated DBPs via tap water ingestion. Boiling of tap water has been found to significantly reduce the concentrations of halogenated DBPs. In this study, we found that compared with boiling only, adding ascorbate (vitamin C) or carbonate (baking soda) to tap water and then boiling the water further reduced the level of total organic halogen (a collective parameter for all halogenated DBPs) by up to 36% or 28%, respectively. Adding ascorbate removed the chlorine residual in tap water and thus prevented the formation of more halogenated DBPs in the boiling process. Adding carbonate elevated pH of tap water and consequently enhanced the hydrolysis (dehalogenation) of halogenated DBPs or led to the formation of more trihalomethanes that might volatilize to air during the boiling process. The comparative developmental toxicity of the DBP mixtures in the water samples was also evaluated. The results showed that adding a tiny amount of sodium ascorbate or carbonate (2.5-5.0 mg/L) to tap water followed by boiling for 5 min reduced the developmental toxicity of tap water to a substantially lower level than boiling only. The addition of sodium ascorbate or carbonate to tap water in household could be realized by preparing them in tiny pills. This study suggests simple and effective methods to reduce the adverse effects of halogenated DBPs on humans through tap water ingestion.


Assuntos
Desinfetantes/toxicidade , Poluentes Químicos da Água/toxicidade , Ácido Ascórbico , Carbonatos , Cloro , Desinfetantes/análise , Desinfecção/métodos , Água Potável/química , Halogenação , Halogênios , Humanos , Trialometanos/análise , Volatilização , Poluentes Químicos da Água/análise , Purificação da Água/métodos
5.
Bull Environ Contam Toxicol ; 105(3): 468-473, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32886144

RESUMO

Selenium (Se), iron (Fe), and free sulfides contents in pore waters were measured to study the liberation of soluble Se in suboxic conditions. The sediment core was collected in a salt marsh in Patos Lagoon estuary (southern Brazil), and it was obtained during a brackish water period, in a low intertidal stand vegetated by Spartina alterniflora. The redox potential (Eh), pH, andacid volatile sulfides (AVS) content were also investigated. Pore water results sustained the idea that S. alterniflora roots promote oxygen penetration to depths of ca. 10 cm below the salt marsh surface, increasing Eh and lowering the pH in this interval. High Se concentrations (e.g., 16.9 µg L-1), that are above US. EPA environmental criteria, were observed in the pore water to depths between 10 and 20 cm and are associated to low AVS contents and high concentrations of free sulfides. In the first 10 cm the lowering of Se contents probably happens due the low pH and biological volatilization of the metalloid.


Assuntos
Sedimentos Geológicos/química , Selênio/análise , Áreas Alagadas , Brasil , Estuários , Ferro/análise , Poaceae , Sulfetos/análise , Volatilização
6.
J Chromatogr A ; 1627: 461405, 2020 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823110

RESUMO

This study focused on the measurements and validity of relative distribution constants of vaporized hydrocarbons between air and polydimethylsiloxane (PDMS) using commercially available capillary columns. Capillary column gas chromatography (CCGC) measurements, using two columns containing a PDMS stationary phase with different film thicknesses, were conducted to determine the relative distribution constants of n-heptane, toluene, n-octane, p-xylene, n-nonane, and 1,2,4-trimethylbenzene between air and PDMS at 90 and 120 °C. To validate the accuracy of the relative distribution constants via CCGC, the compositions of three headspace samples containing different amounts of hydrocarbons were calculated using the relative distribution constants via CCGC and extracted amounts via PDMS solid phase microextraction (SPME) at 90 and 120 °C. It was found that calculated hydrocarbon compositions of headspace samples were comparable to true headspace hydrocarbon compositions via direct vapor analysis, with an average absolute relative error of 3.2%. Our results indicate that CCGC is an alternative method that can provide a reliable and convenient method to determine the relative distribution constants of various hydrocarbons between air and PDMS for quantitative chemical analysis of headspace.


Assuntos
Ar , Dimetilpolisiloxanos/química , Hidrocarbonetos/análise , Cromatografia de Fase Reversa , Hidrocarbonetos/química , Microextração em Fase Sólida , Volatilização
7.
Food Chem Toxicol ; 145: 111702, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32860861

RESUMO

Our surrounding environment, especially often-touched contaminated surfaces, plays an important role in the transmission of pathogens in society. The shortage of effective sanitizing fluids, however, became a global challenge quickly after the coronavirus disease-19 (COVID-19) outbreak in December 2019. In this study, we present the effect of surfactants on coronavirus (SARS-CoV-2) virucidal efficiency in sanitizing fluids. Sodium dodecylbenzenesulfonate (SDBS), sodium laureth sulfate (SLS), and two commercial dish soap and liquid hand soap were studied with the goal of evaporation rate reduction in sanitizing liquids to maximize surface contact time. Twelve fluids with different recipes composed of ethanol, isopropanol, SDBS, SLS, glycerin, and water of standardized hardness (WSH) were tested for their evaporation time and virucidal efficiency. Evaporation time increased by 17-63% when surfactant agents were added to the liquid. In addition, surfactant incorporation enhanced the virucidal efficiency between 15 and 27% according to the 4-field test in the EN 16615:2015 European Standard method. Most importantly, however, we found that surfactant addition provides a synergistic effect with alcohols to inactivate the SARS-CoV-2 virus. This study provides a simple, yet effective solution to improve the virucidal efficiency of commonly used sanitizers.


Assuntos
Antivirais/farmacologia , Betacoronavirus/efeitos dos fármacos , Infecções por Coronavirus/prevenção & controle , Higienizadores de Mão/farmacologia , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Sabões/farmacologia , Tensoativos/farmacologia , 2-Propanol/farmacologia , Células A549 , Benzenossulfonatos/farmacologia , Sinergismo Farmacológico , Etanol/farmacologia , Glicerol/farmacologia , Humanos , Dodecilsulfato de Sódio/análogos & derivados , Dodecilsulfato de Sódio/farmacologia , Volatilização/efeitos dos fármacos
9.
Waste Manag ; 114: 1-16, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32622291

RESUMO

Development of thermal processes for selective recovery of Zn and other valuable elements from municipal solid waste incineration (MSWI) fly ash requires comprehensive knowledge of the impact of gas atmosphere on the volatile behaviour of the element constituents of the ash at different reaction temperatures. This study assesses the partitioning of 18 elements (Al, As, Bi, C, Ca, Cd, Cl, Cu, K, Mg, Na, P, Pb, S, Sb, Sn, Ti, and Zn) between condensed and gaseous phases during thermal treatment of MSWI fly ash in both oxidising gas and reducing gas atmospheres, at different temperatures spanning the range 200-1050 °C. The operating atmosphere had major impacts on the partitioning of the following elements: As, Bi, C, Cd, Cu, Na, Pb, S, Sb, Sn, and Zn. The partitioning of these elements cannot be accurately predicted over the full range of investigated operating conditions with global thermodynamic equilibrium calculations alone, i.e. without also considering chemical kinetics and mass transfer. In oxidising conditions, the following elements were predominately retained in condensed phases, even at high temperatures: As, Bi, Sb, Sn, and Zn. All these elements, except As, were largely released to the gas phase (>70%) at high temperatures in reducing conditions. The impact of gas atmosphere on the volatility of Cd and Pb was greatest at low reaction temperatures (below ~750 °C). Results for volatile matrix elements, specifically C, Cl, K, Na, and S, are interpreted in terms of the mechanisms governing the release of these elements to the gas phase.


Assuntos
Metais Pesados/análise , Oligoelementos/análise , Carbono , Cinza de Carvão , Incineração , Material Particulado , Resíduos Sólidos/análise , Volatilização
10.
Sci Total Environ ; 741: 140148, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32610229

RESUMO

People spend 80% of their time indoors exposed to poor air quality due to mold growth in humid air as well as human activities (painting, cooking, cleaning, smoking…). To better understand the impact of molds on indoor air quality, we studied the emission of microbial Volatile Organic Compounds (mVOCs) from Aspergillus niger, cultivated on malt agar extract, using a high-resolution proton transfer reaction- time of flight- mass spectrometer (PTR-TOF-MS). These emissions were studied for different cultivation time and indoor relative humidities. Our results show that the concentration of the known C4-C9 mVOCs tracers of the microbial activity (like 1-octen-3-ol, 3-methylfuran, 2-pentanone, dimethyl sulfide, dimethyl disulfide, nitromethane, 1,3-octadiene…) was the highest in the early stage of growth. However, these emissions decreased substantially after a cultivation time of 10-14 days and were highly affected by the relative humidity. In addition, the emissions of certain mVOCs were sensitive to indoor light, suggesting an impact of photochemistry on the relative amounts of indoor mVOCs. Based on this study, an estimation of the mVOC concentration for a standard living room was established at different air exchange rates and their indoor lifetimes toward hydroxyl radicals and ozone were also estimated. These findings give insights on possible mVOCs levels in moisture-damaged buildings for an early detection of microbial activity and new evidences about the effect of indoor light on their emission.


Assuntos
Poluição do Ar em Ambientes Fechados , Compostos Orgânicos Voláteis/análise , Aspergillus niger , Humanos , Volatilização
11.
Sci Total Environ ; 741: 140433, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32610240

RESUMO

Ammonia (NH3) volatilization is a major pathway of nitrogen (N) losses from paddy fields, and could be potentially mitigated by cultivation of high nitrogen use efficiency (high-NUE) rice cultivars. However, the relationship between NUE and NH3 volatilization has not been validated under field conditions. A field experiment was conducted to evaluate the impact of four rice cultivars with different NUE [Wuyunjing 23 (W23), Zhendao 11 (Z11), Wuyujing 3 (W3), and Aoyusi 386 (A386)] on NH3 volatilization, as well as the related mechanisms. Two high-NUE rice cultivars W23 and Z11 was not more effective in reducing total NH3 volatilization from the paddy field compared to cultivar A386 with the lowest NUE. Cultivar A386 had 12.7-17.8% and 35.7-54.1% lower NH3 volatilization than other three rice cultivars at tillering fertilization stage (TFS) and panicle fertilization stage (PFS), respectively, mainly due to its greater shoot N accumulation, root biomass and volume at TFS and its greater shoot biomass, leaf area index and shoot N accumulation at PFS. There was no significant difference in NH3 volatilization among W23, Z11 and W3 at TFS. However, premature senescence phenomenon at later growth stages of A386 eventually led to its lowest NUE among the four rice cultivars. Our results suggest that NUE of rice does not link to NH3 volatilization from paddy fields. In order to make high-NUE rice cultivars also effective in mitigating NH3 volatilization, future breeding works should aim to improve N uptake capability and canopy structure at early tillering and panicle development stages while prevent premature senescence of rice plants to maintain high yields.


Assuntos
Amônia/análise , Oryza , Fertilizantes/análise , Nitrogênio/análise , Solo , Volatilização
12.
Br J Hosp Med (Lond) ; 81(7): 1-7, 2020 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-32730160

RESUMO

BACKGROUND: COVID-19 has caused an unprecedented pandemic and medical emergency that has changed routine care pathways. This article discusses the extent of aerosolisation of severe acute respiratory syndrome coronavirus 2, the virus that causes COVID-19, as a result of oesophagogastroduodenoscopy and colonoscopy. METHODS: PubMed and Google Scholar were searched for relevant publications, using the terms COVID-19 aerosolisation, COVID-19 infection, COVID-19 transmission, COVID-19 pandemic, COVID-19 and endoscopy, Endoscopy for COVID-19 patients. RESULTS: A total of 3745 articles were identified, 26 of which were selected to answer the question of the extent of SARS-CoV-2 aerosolisation during upper and lower gastrointestinal endoscopy. All studies suggested high infectivity from contact and droplet spread. No clinical study has yet reported the viral load in the aerosol and therefore the infective dose has not been accurately determined. However, aerosol-generating procedures are potentially risky and full personal protective equipment should be used. CONCLUSIONS: As it is a highly infectious disease, clinicians treating patients with COVID-19 require effective personal protective equipment. The main routes of infection are direct contact and droplets in the air and on surfaces. Aerosolisation carries a substantial risk of infection, so any aerosol-producing procedure, such as endoscopy, should be performed wearing personal protective equipment and with extra caution to protect the endoscopist, staff and patients from cross-infection via the respiratory system.


Assuntos
Colonoscopia/efeitos adversos , Infecções por Coronavirus/prevenção & controle , Infecções por Coronavirus/transmissão , Endoscopia do Sistema Digestório/efeitos adversos , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Pneumonia Viral/transmissão , Volatilização , Aerossóis/efeitos adversos , Poluentes Ocupacionais do Ar/efeitos adversos , Betacoronavirus , Humanos , Controle de Infecções , Transmissão de Doença Infecciosa do Paciente para o Profissional/prevenção & controle , Equipamento de Proteção Individual
13.
J Vis Exp ; (160)2020 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-32658181

RESUMO

This protocol demonstrates a method for graphene-assisted quick growth and coalescence of AlN on nano-pattened sapphire substrate (NPSS). Graphene layers are directly grown on NPSS using catalyst-free atmospheric-pressure chemical vapor deposition (APCVD). By applying nitrogen reactive ion etching (RIE) plasma treatment, defects are introduced into the graphene film to enhance chemical reactivity. During metal-organic chemical vapor deposition (MOCVD) growth of AlN, this N-plasma treated graphene buffer enables AlN quick growth, and coalescence on NPSS is confirmed by cross-sectional scanning electron microscopy (SEM). The high quality of AlN on graphene-NPSS is then evaluated by X-ray rocking curves (XRCs) with narrow (0002) and (10-12) full width at half-maximum (FWHM) as 267.2 arcsec and 503.4 arcsec, respectively. Compared to bare NPSS, AlN growth on graphene-NPSS shows significant reduction of residual stress from 0.87 GPa to 0.25 Gpa, based on Raman measurements. Followed by AlGaN multiple quantum wells (MQWS) growth on graphene-NPSS, AlGaN-based deep ultraviolet light-emitting-diodes (DUV LEDs) are fabricated. The fabricated DUV-LEDs also demonstrate obvious, enhanced luminescence performance. This work provides a new solution for the growth of high quality AlN and fabrication of high performance DUV-LEDs using a shorter process and less costs.


Assuntos
Óxido de Alumínio/química , Grafite/química , Nanoestruturas/química , Semicondutores , Raios Ultravioleta , Compostos de Alumínio/química , Catálise , Gálio/química , Gases/química , Luminescência , Volatilização
14.
PLoS One ; 15(7): e0233250, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32730274

RESUMO

Intelligent systems in nature like the mammalian nervous system benefit from adaptable inputs that can tailor response profiles to their environment that varies in time and space. Study of such plasticity, in all its manifestations, forms a pillar of classical and modern neuroscience. This study is concerned with a novel form of plasticity in the olfactory system referred to as induction. In this process, subjects unable to smell a particular odor, or unable to differentiate similar odors, gain these abilities through mere exposure to the odor(s) over time without the need for attention or feedback (reward or punishment). However, few studies of induction have rigorously documented changes in olfactory threshold for the odor(s) used for "enrichment." We trained 36 CD-1 mice in an operant-olfactometer (go/no go task) to discriminate a mixture of stereoisomers from a lone stereoisomer using two enantiomeric pairs: limonene and carvone. We also measured each subject's ability to detect one of the stereoisomers of each odor. In order to assess the effect of odor enrichment on enantiomer discrimination and detection, mice were exposed to both stereoisomers of limonene or carvone for 2 to 12 weeks. Enrichment was effected by adulterating a subject's food (passive enrichment) with one pair of enantiomers or by exposing a subject to the enantiomers in daily operant discrimination testing (active enrichment). We found that neither form of enrichment altered discrimination nor detection. And this result pertained using either within-subject or between-subject experimental designs. Unexpectedly, our threshold measurements were among the lowest ever recorded for any species, which we attributed to the relatively greater amount of practice (task replication) we allowed our mice compared to other reports. Interestingly, discrimination thresholds were no greater (limonene) or only modestly greater (carvone) from detection thresholds suggesting chiral-specific olfactory receptors determine thresholds for these compounds. The super-sensitivity of mice, shown in this study, to the limonene and carvone enantiomers, compared to the much lesser acuity of humans for these compounds, reported elsewhere, may resolve the mystery of why the former group with four-fold more olfactory receptors have tended, in previous studies, to have similar thresholds to the latter group. Finally, our results are consistent with the conclusion that supervised-perceptual learning i.e. that involving repeated feedback for correct and incorrect decisions, rather than induction, is the form of plasticity that allows animals to fully realize the capabilities of their olfactory system.


Assuntos
Odorantes/análise , Olfatometria , Percepção Olfatória/efeitos dos fármacos , Animais , Limoneno/química , Limoneno/farmacologia , Camundongos , Volatilização
15.
Sci Total Environ ; 743: 140799, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32673926

RESUMO

Paddy Azolla is considered as a promising technical approach to reduce ammonia (NH3) volatilization and increase nitrogen use efficiency (NUE). However, it is not effective in highly fertilized paddy fields as the high ammonium N (NH4+-N) concentrations adversely inhibit the growth and N uptake of Azolla. Urease inhibitors could effectively decrease NH4+-N concentrations in surface water and NH3 volatilization. However, a lack of information still exists regarding the combined effects of Azolla and urease inhibitors on NH3 volatilization, NUE, and grain yield (GY) of rice. A two-year field experiment was conducted including five treatments (no urea application (control), urea (N), urea + Azolla (NA), urea + urease inhibitor (NUI), and urea + Azolla + urease inhibitor (NAUI)). Results showed that NA treatment (-25.2%) was not effective in reducing NH3 volatilization compared with NUI treatment (-43.3%). The NAUI treatment substantially reduced NH3 volatilization (-54.6%) more than that by NA and NUI treatments, primarily because of the lower NH4+-N concentrations, pH, and temperature in surface water. Furthermore, NAUI treatments significantly increased the grain yield (GY) and the apparent N recovery efficiency (ANRE) of rice by 9.0-9.7% and 66.0-71.3%, respectively. The significant increase in GY was mainly from the increased panicle number (4.0%), spikelet number per panicle (15.9%), and total biomass (22.9%), which caused by the enhanced total N uptake (35.8%). NAUI treatment also decreased the yield-scaled NH3 volatilization by 61.1-63.6%. Overall, the co-application of Azolla and urease inhibitor in the rice field substantially decreased NH3 volatilization, and increased NUE and rice yield.


Assuntos
Amônia/análise , Oryza , Agricultura , Fertilizantes/análise , Nitrogênio/análise , Solo , Urease , Volatilização
16.
PLoS One ; 15(7): e0236276, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32730348

RESUMO

Red turpentine beetle, Dendroctonus valens (Coleoptera: Curculionidae: Scolytinae) is a non-aggressive pine bark beetle native to North America, and more aggressive invader in China. Dispersing pioneer beetles are attracted to potential host trees by oleoresin monoterpene kairomones, but respond more strongly to those combined with ethanol, a mixture often released from stressed, dying, or recently dead trees. (+)-3-Carene, usually the dominant or co-dominant monoterpene in ponderosa pine, Pinus ponderosa, is a stronger attractant than α-pinene or ß-pinene where tested over a large portion of the D. valens range, while (+)-3-carene+ethanol was shown previously to attract twice the beetles of (+)-3-carene. A field test comparing D. valens attraction among the three monoterpenes when all are released with ethanol has never been reported, and was our objective. In three US Pacific Northwestern pine forests, (-)-ß-pinene+ethanol lures attracted 1.4 to 1.9 times more beetles than (+)-3-carene+ethanol. (+)- or (±)-α-pinene+ethanol lures were least attractive. A 1:1:1 monoterpene mixture+ethanol lure attracted more beetles than the 1:1:1 lure, but it was not statistically higher. Monoterpenes were dispensed from low density polyethylene bottles and their release rates monitored in laboratory and field tests. Under laboratory conditions (+)-3-carene was released much more rapidly than (+)-α-pinene or (-)-ß-pinene when dispensed separately, or in a 1:1:1 mixture. (+)-3-Carene in the 1:1:1 mixture increased the release of both pinenes over their rates when dispensed separately. (-)-ß-Pinene+ethanol is currently the strongest kairomone lure for D. valens attraction in US northwest pine forests, and has value for beetle detection, monitoring, research, and management.


Assuntos
Monoterpenos Bicíclicos/farmacologia , Besouros/fisiologia , Etanol/farmacologia , Florestas , Terebintina/farmacologia , Animais , Monoterpenos Bicíclicos/química , Besouros/efeitos dos fármacos , Geografia , Laboratórios , Noroeste dos Estados Unidos , Polietileno/química , Temperatura , Volatilização
17.
Environ Pollut ; 265(Pt A): 114850, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32474341

RESUMO

We investigated the concentrations, distributions, potential sources, and air-soil exchange of 10 OPFRs in the air and soil of Dalian. The concentrations of Σ10OPFRs in the soil were in the range of 1.07-288 ng/g (mean: 14.0 ng/g), while the concentrations of Σ10OPFRs in the passive air samples were in the range of 313-4760 pg/m3 (mean: 1630 pg/m3). Generally, the concentrations of OPFRs are relatively high in urban areas compared with those in suburban and rural areas, indicating the influence of intensive anthropogenic activities on local OPFR concentrations. Tris(2-chloroisopropyl) phosphate (TCIPP) was the most abundant congener, followed by tris(2-chloroethyl) phosphate (TCEP) and tri-n-butyl phosphate (TNBP). Spearman correlation analysis illustrated that OPFRs in the air shared common sources, while the sources of OPFRs in the soil were diverse. Net volatilization of TNBP from the soil to the air was observed at all sampling sites, whereas opposite trends were observed for TCIPP, TDCIPP, TBOEP, TPHP, EHDPP, TEHP, TPPO, and TMPP. The exchange trends of TCEP were characterized as volatilization in urban areas, but equilibrium in rural ones. TCEP showed the highest volatilization flux (1100 ng/m3/d), whereas TCIPP showed the highest deposition flux (-171 ng/m3/d). The significant diffusive fluxes of certain OPFRs, especially of those with suspected toxicities, suggested potential high exposure levels to these chemicals.


Assuntos
Retardadores de Chama/análise , China , Monitoramento Ambiental , Organofosfatos , Solo , Volatilização
18.
Environ Pollut ; 265(Pt A): 114862, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32497822

RESUMO

The losses of excessive reactive nitrogen (N) from agricultural production pose detrimental impacts on water, air and land. However, N budgets of agroecosystems are still poorly quantified, presenting a barrier to understand the N turnover in agriculture. Agricultural ammonia (NH3) volatilization has been recognized as a crucial contribution to the pollution of fine particulate matters over China through reacting with acid gases. Building on these challenges, the first national-scale model analysis was constructed on the N budgets to gain an overall insight into the current status of N flows in Chinese dryland systems towards sustainable N management. Total inputs of soil N in Chinese dryland soils were estimated at 121 kg N ha-1 in 2010, considering all pathways including N manure, fertilizer, atmospheric deposition and litter from crop residues. Atmospheric N deposition accounted for 25% of N fertilizer plus N manure in Chinese dryland soils, suggesting that N deposition could not be ignored when estimating total N inputs to Chinese dryland soils. The highest ratio of NH3 volatilization to total N outputs was found at 43 kg N ha-1 (∼21%) in Northern China, followed by 41 kg N ha-1 (∼20%) in Sichuan Basin and 25 kg N ha-1 (∼26%) in Northeastern China. The modeling results indicated that, if a 20% decrease in N fertilizer plus N manure was achieved, it would lead to a 24% (7-49%) reduction in NH3 volatilization. Substantial reductions of NH3 volatilization would also be achieved by making an improvement in changing management practices (controlled release fertilizer and full irrigation). The results would give an overall insight into N budgets in Chinese dryland soils. The constructed N budgets assisted with understanding agricultural N flows and NH3 pollution, and evaluated the impacts of human activities on N cycle towards a precise way to regulate agricultural management.


Assuntos
Amônia/análise , Nitrogênio/análise , Agricultura , China , Ecossistema , Fertilizantes/análise , Esterco , Solo , Volatilização
19.
Environ Sci Pollut Res Int ; 27(25): 31211-31220, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32488714

RESUMO

The purpose of this study is to observe the effects of stock markets and exchange rate volatility on environmental pollution in Pakistan during the period 1985-2018. A nonlinear autoregressive distributed lag (ARDL) model is applied to get this objective. In general, the short-term results revealed that the positive and negative shocks in stock markets reducing the carbon emissions. In adverse, positive shocks in exchange rate volatility reduces the carbon emissions while negative shocks in exchange rate volatility have a positive significant effect on carbon emissions in Pakistan. Moreover, the positive and negative shocks in the stock market have a positive significant effect on Pakistan's carbon emissions but positive and negative shocks in exchange rate volatility negative influence on carbon emissions in the long run. The findings further show that positive and negative shocks of the stock markets and exchange rate volatility have the same effects in sign but different in magnitude in the long run. Based on these findings, some policy recommendations proposed in the context of Pakistan as well as for other developing countries.


Assuntos
Dióxido de Carbono/análise , Desenvolvimento Econômico , Poluição Ambiental/análise , Paquistão , Volatilização
20.
Environ Sci Pollut Res Int ; 27(25): 31892-31904, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32506403

RESUMO

This study inspects the empirical association between inflation instability, GDP growth volatility, and the environmental quality in Pakistan, covering the period 1975-2018 by using an asymmetric autoregressive distributed lag (ARDL) methodological approach. The asymmetric ARDL results document that positive and negative shocks of inflation instability have different effects on environmental quality. Negative shocks of inflation instability have a positive influence on carbon dioxide emissions (CO2) and nitrous oxide emissions (N2O), while positive shocks of inflation instability have insignificant effects in the long run. Asymmetric findings also suggest that positive and negative fluctuations in GDP growth volatility affect CO2 and N2O emissions differently, while they have insignificant results on methane emissions (CH4) in the long run. Additionally, in the short run, positive and negative shocks of inflation instability and GDP growth volatility behave differently in terms of their impact on pollution emissions. Based on these findings, the study opens up innovative intuitions for policymakers to support a robust role of economic stability in attaining targets relevant to pollution reduction.


Assuntos
Desenvolvimento Econômico , Gases de Efeito Estufa , Dióxido de Carbono/análise , Poluição Ambiental/análise , Paquistão , Volatilização
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