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1.
Water Sci Technol ; 80(3): 597-606, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31596270

RESUMO

Despite recent developments in process-based modeling of treatment wetlands (TW), the dynamic response of horizontal flow (HF) aerated wetlands to interruptions of aeration has not yet been modeled. In this study, the dynamic response of organic carbon and nitrogen removal to interruptions of aeration in an HF aerated wetland was investigated using a recently-developed numerical process-based model. Model calibration and validation were achieved using previously obtained data from pilot-scale experiments. Setting initial concentrations for anaerobic bacteria to high values (≈ 35-70 mg L-1) and including ammonia sorption was important to simulate the treatment performance of the experimental wetland in transition phases when aeration was switched off and on again. Even though steady-state air flow rate impacted steady-state soluble chemical oxygen demand (CODs), ammonia nitrogen (NH4-N) and oxidized nitrogen (NOx-N) concentration length profiles, it did not substantially affect corresponding effluent concentrations during aeration interruption. When comparing simulated with experimental results, it is most likely that extending the model to include mass transfer through the biofilm will allow to better explain the underlying experiments and to increase simulation accuracy. This study provides insights into the dynamic behavior of HF aerated wetlands and discusses assumptions and limitations of the modeling approach.


Assuntos
Carbono/análise , Nitrogênio/análise , Eliminação de Resíduos Líquidos , Poluição da Água/estatística & dados numéricos , Áreas Alagadas , Análise da Demanda Biológica de Oxigênio , Desnitrificação
2.
Sci Total Environ ; 690: 1131-1139, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31470476

RESUMO

Dissolved organic carbon (DOC) turnover in aquatic environments is modulated by the presence of other key macronutrients, including nitrogen (N) and phosphorus (P). The ratio of these nutrients directly affects the rates of microbial growth and nutrient processing in the natural environment. The aim of this study was to investigate how labile DOC metabolism responds to changes in nutrient stoichiometry using 14C tracers in conjunction with untargeted analysis of the primary metabolome in upland peat river sediments. N addition led to an increase in 14C-glucose uptake, indicating that the sediments were likely to be primarily N limited. The mineralisation of glucose to 14CO2 reduced following N addition, indicating that nutrient addition induced shifts in internal carbon (C) partitioning and microbial C use efficiency (CUE). This is directly supported by the metabolomic profile data which identified significant differences in 22 known metabolites (34% of the total) and 30 unknown metabolites (16% of the total) upon the addition of either N or P. 14C-glucose addition increased the production of organic acids known to be involved in mineral P dissolution (e.g. gluconic acid, malic acid). Conversely, when N was not added, the addition of glucose led to the production of the sugar alcohols, mannitol and sorbitol, which are well known microbial C storage compounds. P addition resulted in increased levels of several amino acids (e.g. alanine, glycine) which may reflect greater rates of microbial growth or the P requirement for coenzymes required for amino acid synthesis. We conclude that inorganic nutrient enrichment in addition to labile C inputs has the potential to substantially alter in-stream biogeochemical cycling in oligotrophic freshwaters.


Assuntos
Monitoramento Ambiental , Sedimentos Geológicos/química , Poluentes da Água/análise , Carbono/análise , Água Doce/química , Nitrogênio/análise , Fósforo/análise
3.
Ying Yong Sheng Tai Xue Bao ; 30(9): 3183-3194, 2019 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-31529894

RESUMO

Soil organic carbon is essential for maintaining terrestrial ecosystem function and mitigating soil degradation. Soil microorganisms participate in soil carbon cycling. They are affected by tillage methods and straw returning. A split-plot design was adopted in this experiment. The whole-plot treatment had two tillage methods, subsoil tillage (ST) and rotary tillage (RT). The split-plot treatment included full straw returning (F) and no straw returning (0). The microbial community structure and carbon sequestration genes were assessed by Illumina sequencing technique. Soil organic carbon contents were measured during 2012-2017. The results showed that 1) subsoil tillage and straw returning significantly increased pH, microbial biomass carbon, total nitrogen, silt content, and clay content, while significantly decreased sand content; 2) during the test period (2012-2017), soil organic carbon (SOC) content under all treatments showed an increasing trend, but the increment for average SOC content under straw returning and subsoiling treatments was significantly higher than that of no straw returning and rotary tillage by 33.2 % and 30.6%, respectively; 3) Proteobacteria was the most abundant type of bacteria in the soil, followed by Acidobacteria and Gemmatadanetes; 4) STF treatment maintained high microbial diversity; 5) Excepted for soil sand content, soil pH, microbial biomass carbon, total nitrogen, silt content and clay content all caused the variation of soil microbial community structure under the STF treatment in the direction of SOC accumulation; 6) in addition to the gene abundance in the di- and oligosaccharides metabolic pathway, the gene abundance in the metabolic pathways for CO2 fixation, central carbohydrate metabolism, fermentation, one-carbon metabolism, organic acids, sugar alcohols and glycoside hydrolases showed that subsoil tillage was significantly higher than rotary tillage, with posi-tively correlation with soil organic carbon content. Therefore, the combination of subsoil tillage and straw returning could improve basic soil properties, affect soil microbial community structure, and increase the capacity of soil carbon fixation, thus providing a realistic basis for solving soil degradation.


Assuntos
Agricultura , Microbiota , Microbiologia do Solo , Solo , Carbono/análise , Triticum
4.
Environ Monit Assess ; 191(9): 541, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31385054

RESUMO

Biophysical parameters affecting biomass carbon have been emphasized in the Paris Agreement for realizing climatic benefits from mitigation projects. The present study was conducted to assess the relation of biophysical parameters with forest biomass carbon in north Kashmir region of Himalayas. The relation of biomass carbon was assessed with (1) species type or strata including Cedrus deodara, mixed I (Cedrus deodara-Pinus wallichiana), mixed II (Abies pindrow-Picea smithiana) and Pinus wallichiana, (2) altitude (1292-2911 m amsl), (3) crown density, (4) aspect, (5) tree count or density and (6) location. Using a stratified sampling design, a total of 188 quadrats of 0.1 ha were laid across the entire region representing different biophysical parameters. Field observation including diameter at breast height and height were recorded and sample biomass (t ha-1) was estimated using volumetric equations. The observed relation of aboveground biomass carbon with species revealed a trend of mixed II ˃ Cedrus deodara ˃ mixed I ˃ Pinus wallichiana. A positive but weak correlation (R2 = 0.02) was found between aboveground biomass carbon and altitude. A reasonably good correlation (R2 = 0.40) was observed to exist between aboveground biomass carbon and crown density. The highest value of average biomass carbon (72.63 t ha-1) was recorded for the north-eastern aspect whereas the lowest value (44.60 t ha-1) was recorded for the eastern aspect. The aboveground biomass carbon and tree count was found positively correlated (+ 0.475, R2 = 0.48). Forest biomass carbon fluctuates within the same geographical region with a variety of biophysical factors. The growth rate of species, photosynthetic ability under different crown densities and climatic conditions could address the reasons for this variability. Biophysical relations of forest biomass carbon can be viewed as an important input for guidelines and policy matters on climate change.


Assuntos
Biomassa , Carbono/análise , Cedrus/crescimento & desenvolvimento , Mudança Climática/estatística & dados numéricos , Monitoramento Ambiental/métodos , Pinus/crescimento & desenvolvimento , Altitude , Florestas , Índia , Paquistão , Árvores/crescimento & desenvolvimento
5.
Environ Monit Assess ; 191(9): 552, 2019 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-31399843

RESUMO

The present work aims to observe the spatial distribution of metals associated with carbon forms (fraction < 2 mm) in surface sediments of two macrotidal estuaries, São Marcos Bay and Anil River Estuary, which are located within the transition region between the Amazonian and the semi-arid northeast regions. Grain size, metal content (Al, Fe, Mn, Cu, Pb, Cr, Zn, and Ni), organic matter, and calcium carbonate content were determined. Grain size analyses showed the predominance of the sand-sized fraction < 2 mm due to the local hydrodynamic conditions. Anil River Estuary sediments exhibited high organic matter content due to both the mangrove outwelling and domestic sewage discharge. They also presented high calcium carbonate content as a result of abundant remnants of gastropod shells. Organic matter acted as the primary geochemical carrier for most metals in both estuaries, while calcium carbonate acted as the secondary carrier. Enrichment factors indicated Mn sediment contamination in São Marcos Bay and Fe, Pb, and Zn contamination in the Anil River Estuary. These results also suggest that São Marcos Bay is influenced by harbor activities, mostly ore shipment, whereas Anil River Estuary sediments are enriched in these metals as a result of domestic and hospital effluents reaching the urbanized drainage basin.


Assuntos
Carbono/análise , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Metais Pesados/análise , Rios/química , Poluentes Químicos da Água/análise , Brasil , Carbonato de Cálcio/análise , Carbonatos/análise , Estuários
6.
Environ Monit Assess ; 191(9): 559, 2019 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-31402394

RESUMO

Various daily human activities can result in the release of pollutants of different chemical constituents and specific gravities into natural soils. Pollution of natural soils is a recurring occurrence in the environment and it contributes greatly to the alteration of soils properties. The results of an assessment of the effects of selected petroleum-derived and vegetable oils on soil physicochemical and hydraulic properties are presented in this work. Topsoil samples at a depth of 0-20 cm of the same textural class were collected from the order Lixisols and Nitisol within Ogun State, southwest Nigeria. Surface soil samples were collected and treated with petrol, diesel and palm oil at two different volumes (50 and 100 ml). Investigated soil properties include particle size distribution, soil pH, bulk density (BD), total porosity (TP), saturated hydraulic conductivity (Ksat), available water capacity (AWC), total carbon (TC), total nitrogen (TN), organic matter (OM) content, cation exchange capacity (CEC), potassium, sodium, and soil resistivity. Analysis of variance and Pearson's correlation were used to study the variations of the relationship of analyzed soil properties under different soil types and treatments. The regression analysis shows that all the generated models for predicting Ksat values under different soil treatments had R2 values ranging from 0.999 to 1.000. Results showed that treatment with either petroleum-derived or lipids has no effects on soil pH and textural class. Results further revealed that palm oil contamination at 50 ml recorded least values of Ksat in the two soil types. In all cases, BD and Ksat of the contaminated soils of the two sampling locations were reduced compared with their control values. Correlation coefficient showed expected strong negative correlation between TP and BD as well as between any two of organic parameters (TC, TN, and OM) and soil resistivity, TC, and TN at 1% level in both soil types. Two-way ANOVA showed that there were significant differences at 5% level between the two locations with respects to BD, TP, and CEC while significant differences in Ksat, pH, TC, TN, and OM occur between soils from the two locations under various treatments at 5% level.


Assuntos
Monitoramento Ambiental , Petróleo/análise , Poluentes do Solo/análise , Carbono/análise , Humanos , Nigéria , Nitrogênio/análise , Óleos Vegetais/análise , Solo/química , Água/análise
7.
Ying Yong Sheng Tai Xue Bao ; 30(8): 2567-2574, 2019 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-31418179

RESUMO

The study aimed to reveal the cumulative effects and stability characteristics of soil organic carbon (SOC) during forest development at the Mu Us sandy land, China. Using space for time substitution, surface soil samples were collected from semi-fixed sandy lands and restored arbor and shrub lands with the ages of 22, 32 and 53 years in the Yulin sand control region in Northern Shaanxi Province. The content of total organic carbon (TOC), oxidizable labile organic carbon, and resistant carbon and the characteristics of mineralized carbon emission and decomposition ratio were analyzed. The results showed that the increment of TOC for 22 to 53 years shrub and arbor lands from resistant carbon were 3.5-6.2 g·kg-1 and 3.2-7.7 g·kg-1, and from oxidized labile carbon were 2.8-3.4 g·kg-1 and 1.3-2.8 g·kg-1, respectively, compared with semi-fixed sand land. The ratio of soil oxidizable labile carbon in shrub land and arbor land were stable and maintained at 37.0% and 26.8%, respectively. However, the ratio decreased to 25.7% and 17.4% after incubated at a constant temperature for 60 days. The mineralization rate of shrub and arbor lands with 22-53 years was not significant at the ending of soil incubation. Carbon losses from oxidized liable carbon were 76.9%-98.7%, and only 1.3%-23.5% from resistant carbon in all sand-fixing forest plots. Compared with the maximum carbon emission rate, the soil cumulative carbon release exhibited a higher correlation with soil enzyme activities of ß-glucosidase and dehydrogenase, but the enzyme activities did not change from 32-53 years. In conclusion, SOC pool showed stable characteristics of lower emission and higher sequestration with the increases of sand-fixing forest stand age. The carbon fixation effect of arbor sand-fixing forest was better than that of shrub sand-fixing forest.


Assuntos
Carbono/análise , Florestas , Solo/química , Sequestro de Carbono , China
8.
JAMA ; 322(6): 546-556, 2019 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-31408135

RESUMO

Importance: While air pollutants at historical levels have been associated with cardiovascular and respiratory diseases, it is not known whether exposure to contemporary air pollutant concentrations is associated with progression of emphysema. Objective: To assess the longitudinal association of ambient ozone (O3), fine particulate matter (PM2.5), oxides of nitrogen (NOx), and black carbon exposure with change in percent emphysema assessed via computed tomographic (CT) imaging and lung function. Design, Setting, and Participants: This cohort study included participants from the Multi-Ethnic Study of Atherosclerosis (MESA) Air and Lung Studies conducted in 6 metropolitan regions of the United States, which included 6814 adults aged 45 to 84 years recruited between July 2000 and August 2002, and an additional 257 participants recruited from February 2005 to May 2007, with follow-up through November 2018. Exposures: Residence-specific air pollutant concentrations (O3, PM2.5, NOx, and black carbon) were estimated by validated spatiotemporal models incorporating cohort-specific monitoring, determined from 1999 through the end of follow-up. Main Outcomes and Measures: Percent emphysema, defined as the percent of lung pixels less than -950 Hounsfield units, was assessed up to 5 times per participant via cardiac CT scan (2000-2007) and equivalent regions on lung CT scans (2010-2018). Spirometry was performed up to 3 times per participant (2004-2018). Results: Among 7071 study participants (mean [range] age at recruitment, 60 [45-84] years; 3330 [47.1%] were men), 5780 were assigned outdoor residential air pollution concentrations in the year of their baseline examination and during the follow-up period and had at least 1 follow-up CT scan, and 2772 had at least 1 follow-up spirometric assessment, over a median of 10 years. Median percent emphysema was 3% at baseline and increased a mean of 0.58 percentage points per 10 years. Mean ambient concentrations of PM2.5 and NOx, but not O3, decreased substantially during follow-up. Ambient concentrations of O3, PM2.5, NOx, and black carbon at study baseline were significantly associated with greater increases in percent emphysema per 10 years (O3: 0.13 per 3 parts per billion [95% CI, 0.03-0.24]; PM2.5: 0.11 per 2 µg/m3 [95% CI, 0.03-0.19]; NOx: 0.06 per 10 parts per billion [95% CI, 0.01-0.12]; black carbon: 0.10 per 0.2 µg/m3 [95% CI, 0.01-0.18]). Ambient O3 and NOx concentrations, but not PM2.5 concentrations, during follow-up were also significantly associated with greater increases in percent emphysema. Ambient O3 concentrations, but not other pollutants, at baseline and during follow-up were significantly associated with a greater decline in forced expiratory volume in 1 second per 10 years (baseline: 13.41 mL per 3 parts per billion [95% CI, 0.7-26.1]; follow-up: 18.15 mL per 3 parts per billion [95% CI, 1.59-34.71]). Conclusions and Relevance: In this cohort study conducted between 2000 and 2018 in 6 US metropolitan regions, long-term exposure to ambient air pollutants was significantly associated with increasing emphysema assessed quantitatively using CT imaging and lung function.


Assuntos
Poluentes Atmosféricos/efeitos adversos , Poluição do Ar/efeitos adversos , Pulmão/fisiologia , Enfisema Pulmonar , Idoso , Idoso de 80 Anos ou mais , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Carbono/efeitos adversos , Carbono/análise , Estudos de Coortes , Progressão da Doença , Exposição Ambiental/efeitos adversos , Feminino , Humanos , Pulmão/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Óxidos de Nitrogênio/efeitos adversos , Óxidos de Nitrogênio/análise , Ozônio/efeitos adversos , Ozônio/análise , Material Particulado/efeitos adversos , Material Particulado/análise , Enfisema Pulmonar/epidemiologia , Enfisema Pulmonar/fisiopatologia , Testes de Função Respiratória , Tomografia Computadorizada por Raios X , Estados Unidos/epidemiologia
9.
World J Microbiol Biotechnol ; 35(9): 137, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31432268

RESUMO

The presence of very high concentrations of organic pollutants, phenols, tannins and heavy metals mainly chromium in wastewater discharged from leather industries, tags it as one of the most polluting industries. The phenolic syntans discharged from tanning units have an adverse effect on living organisms and cause serious environmental pollution, thereby making it very imperative to remove it. Among various treatment methods available for removal of phenols, biodegradation is environment friendly. The present study aims at the remediation of phenolic syntan used in the leather industry employing individual as well as co-culture of Bacillus cereus and Pseudomonas aeruginosa at varying syntan concentration in the medium. Parameters such as chemical oxygen demand (COD), total organic carbon (TOC), total phenol content (TPC) and Fourier Transform Infrared Spectroscopy (FTIR) indicating biodegradation were analyzed. Promising results were observed with P. aeruginosa, which exhibited a reduction in TPC by 62-72% in all the concentrations of syntan tested just within 12 h of inoculation, whereas about 67 and 83% reduction in COD and TOC respectively was observed for 2000 ppm concentration at the end of 5 days. B. cereus also demonstrated very good reduction in the above parameters however; percentage was less as compared to P. aeruginosa. In the case of co-culture, the TPC reduction was higher than B. cereus but lesser than P. aeruginosa. The percentage reduction in TOC and COD was highest for 500 ppm which eventually decreased for subsequent concentrations.


Assuntos
Bacillus cereus/metabolismo , Resíduos Industriais , Fenóis/metabolismo , Pseudomonas aeruginosa/metabolismo , Poluentes Químicos da Água/metabolismo , Bacillus cereus/crescimento & desenvolvimento , Análise da Demanda Biológica de Oxigênio , Biotransformação , Carbono/análise , Técnicas de Cocultura , Fenóis/análise , Pseudomonas aeruginosa/crescimento & desenvolvimento , Espectroscopia de Infravermelho com Transformada de Fourier , Água/química
10.
Sci Total Environ ; 691: 178-186, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31319254

RESUMO

The leaves and seeds of plants frequently function as the source and sink organs for distinct metabolites, which can interactively vary in response to adverse site conditions. Subtropical soils are typically characterized as having deficient phosphorus (P), calcium (Ca), and magnesium (Mg), with enriched aluminum (Al) and iron (Fe), while Al and manganese (Mn) are toxic at low pH. It remains largely unknown how leaf- and seed-sourced metabolites are synergistically linked to adapt to P-variable soils for trees in subtropical areas. Here we quantified the metabolic and elemental profiling in the mature leaves and immature seeds of Quercus variabilis at contrasting geologically-derived phosphorus sites in subtropical China. The results revealed that carbon (C) and nitrogen (N) based metabolites (primarily sugars and organic acids), as well as enzyme- and protein/nucleic acid-related elements (N, P, Mg, and Mn) played important roles toward characterizing the profiling of metabolites and ionomes in leaves and seeds at two site types, respectively. These metabolites (sugars, amino acids, and fatty acids) and elements (N, P, Mg, and Mn) of seeds were closely related to the sugars, organic acids, and elements (N, P, Mg, and Mn) of leaves at the two site types. For the most part, the content of N and P in the soil affected the accumulation of materials (such as, starchs and proteins) in seeds, as well as N and P assimilation in leaves, by influencing C- and N-containing metabolites in leaves. These results suggested that correlated disparities of C- and N-containing metabolites, along with enzyme- and protein/nucleic acid-related elements in both leaves and seeds played important roles in plants to facilitate their adaptation to nutrient-variable sites in subtropical zones.


Assuntos
Monitoramento Ambiental , Fósforo/análise , Folhas de Planta/metabolismo , Quercus/fisiologia , Sementes/metabolismo , Oligoelementos/análise , Alumínio/análise , Cálcio/análise , Carbono/análise , China , Magnésio/análise , Manganês/análise , Minerais/análise , Nitrogênio/análise , Folhas de Planta/química , Potássio/análise , Quercus/química , Sementes/química , Solo/química
11.
Environ Pollut ; 252(Pt B): 1448-1454, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31265955

RESUMO

The Keban Reservoir, which is the second man-made waterbody in Turkey, has the biggest rainbow trout production in the country. In this study, the impacts of rainbow trout farms on water and sediment chemistry were investigated. Water and sediment samples were taken at distances of 0, 10, 25, 50 and 100 m from the edge of the cages at the three fish farms, and at the respective reference stations. Samples were also taken at 0 m stations and reference stations in the late August when there were no fish in the cages. Physico-chemical variables and trace metals were analysed in all samples. Due to likely high dilution rates and recycling processes in the water column of the reservoir, little changes in the water quality parameters associated with wastes of the fish farms were noticed. When compared with those in the sediment samples at the stations near the edge of cages, the lower concentrations of total phosphorus (TP), total nitrogen (TN), organic matter (OM), total carbon (TC), sulfide (S2-), arsenic (As), cobalt (Co), copper (Cu), manganese (Mn) and zinc (Zn), and higher values of redox potential (Eh) were found at the reference stations. According to organic enrichment classification based on S2- and Eh values, sediments of the three fish farms in the period when there were fish in the cages fell into the oxic category, whereas sediments in the August (no fish farming activity) fell into the normal category. Also, it was found in the August that most of sediment quality parameters at the 0 m stations had close values to those at the reference stations. These results revealed that a three-month period when there were no fish in the cages allows for sediments to return to reference station conditions.


Assuntos
Monitoramento Ambiental/métodos , Pesqueiros , Sedimentos Geológicos/química , Poluentes Químicos da Água/análise , Água/química , Animais , Arsênico/análise , Carbono/análise , Cobre/análise , Fazendas , Peixes , Nitrogênio/análise , Oncorhynchus mykiss , Fósforo/análise , Alimentos Marinhos/análise , Oligoelementos/análise , Turquia , Qualidade da Água , Zinco/análise
12.
Sci Total Environ ; 690: 361-369, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31299570

RESUMO

Thinning plays a major role in forest soil carbon cycling. However, the mechanisms governing soil C fluxes, i.e., C input through litterfall and fine root (FR) production and C output through soil heterotrophic respiration (Rh), remain unclear. To fill this gap, we quantified the C fluxes in the topsoil layer (0-20 cm) by measuring litterfall, FR production and total soil respiration (Rs) (Ra (autotrophic respiration) and Rh) at three thinning intensities (control; low-intensity thinning: extraction of 30% of individual trees; high-intensity thinning (HIT): extraction of 70% of individual trees) in a 26-year-old Chinese fir plantation in southern China. In the control plots, the total C input (110 g C m-2 year-1) via litterfall (59 g C m-2 year-1) and FR production (51 g C m-2 year-1) was much lower than the C output via Rh (518 g C m-2 year-1). This finding demonstrated that the soil is a C source (407 g C m-2 year-1). Furthermore, the C source increased with increasing thinning intensity, particularly under HIT, due to the decreased litterfall return and increased soil CO2 emissions through Rh; this increase occurred despite the increased C input from FR production. In addition, the C output via Rs significantly increased by 42% under HIT due to the stimulation of Ra and Rh. Consequently, thinning reduced the topsoil C pool by 7-8%. Redundancy analysis indicated that the soil C fluxes following thinning were driven by increased FR mortality, understory plant biomass and diversity, and microbial biomass carbon (MBC). Overall, our results indicate that heavy thinning increases soil C loss by increasing soil CO2 emissions and decreasing litterfall return, even under substantially increased FR production. This finding suggests that thinning practices should consider the trade-off between soil C inputs and outputs to reduce the impact of thinning on forest soil carbon sequestration.


Assuntos
Poluentes Atmosféricos/análise , Dióxido de Carbono/análise , Agricultura , Carbono/análise , Ciclo do Carbono , Sequestro de Carbono , China , Cunninghamia , Agricultura Florestal , Florestas , Solo , Árvores
13.
Chemosphere ; 233: 852-861, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31340411

RESUMO

A common strategy to improve indoor air quality in households burning coal and biomass is the introduction of advanced combustion solid fuel stoves, which can use existing fuels yet emit fewer pollutants. Chemical composition of PM is affected by numerous combustion parameters, but is often not considered in energy transitions, despite varying toxicity among chemical components. We analyzed PM2.5 emissions from combustion of solid fuels (coal, wood, and straw; whole and pelletized) in a variety of stoves (cookstoves and heating stoves; traditional and semi-gasifier, including forced versus natural draft and fixed versus reciprocating grate). To assess the effects of fuel and stove type on PM2.5 composition, we measured elemental carbon (EC), organic carbon (OC), water-soluble OC, water-soluble inorganic ions (e.g. SO42-, Cl-, K+), and organic molecular markers. PM2.5 emissions from traditional stoves were mostly carbonaceous: 76-90% organic matter (OM), 5-6% EC, and less than 2% inorganic ions. In contrast, semi-gasifier stoves emitted more inorganic PM2.5: on average, ions comprised 65%, 9% was OM, and 4% was EC. Within the semi-gasifier cookstoves, forced-draft cookstove emissions had lower OM (1-3%) and higher ion concentrations (84-88%) than the natural-draft cookstove (5-14% OM, 30-83% ions). Levoglucosan was detected in PM2.5 from combustion of wood in the traditional cookstove and biomass pellets in the natural-draft semi-gasifier cookstove, but not from wood pellets in the forced-draft semi-gasifier cookstove. Across a range of different fuels and stoves, stove type influenced emitted PM composition more than fuel type, underscoring the impact of combustion conditions on PM chemical composition.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Carbono/análise , Carvão Mineral/análise , Glucose/análogos & derivados , Material Particulado/análise , Biomassa , Culinária , Glucose/análise , Utensílios Domésticos , Produtos Domésticos , Madeira/química
14.
Chemosphere ; 233: 879-887, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31340414

RESUMO

Epidemiological studies have shown that fine particulate matter (PM2.5) has adverse impacts on human health. However, limited studies have investigated the effects of short-term exposure to PM2.5 and its constituents on mortality in China. This study used the generalized linear model (GLM) to investigate the effects of PM2.5 and its constituents, including organic carbon (OC), element carbon (EC), ammonium (NH4+), nitrate (NO3-), sulfate (SO42-), on different causes of mortality in Shanghai from January 1, 2013 to December 31, 2015. The single-day lagged model and the moving average lagged model were used to examine the lagging effects of pollutants on mortality. At lag0 day, PM2.5 had a significant effect on all-cause mortality, and a 10 µg/m3 increase leads to 0.68% increase in all-cause mortality (RR 1.0068, 95%CI 1.0013-1.0123). Among the five constituents, EC had the greatest impact on all-cause mortality in Shanghai, with 10.48% increase of mortality (RR 1.1048, 95%CI 1.0266-1.1891) per 10 µg/m3 increase of concentrations, followed by OC (RR 1.0577, 95%CI 1.0277-1.0886), NH4+ (RR 1.0272, 95%CI 1.0028-1.0522) and SO42- (RR 1.0104, 95%CI 1.0003-1.0206). For respiratory diseases mortality, EC, OC, NO3- and NH4+ had significant impacts and caused an increase of mortality by 44.99% (RR 1.4499, 95%CI 1.1813-1.7794), 10.40% (RR 1.1040, 95%CI 1.0260-1.1880), 5.338% (RR 1.0533, 95%CI 1.0097-1.0989) and 7.34% (RR 1.0734, 95%CI 1.0015-1.1505) per 10 µg/m3 increase of concentrations, respectively. The cumulative effect of PM2.5 on mortality was significant in Shanghai. Except for SO42-, the RR value of the single-day lagged model was smaller than the moving average lagged model.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/análise , Exposição Ambiental/efeitos adversos , Pneumopatias/induzido quimicamente , Pneumopatias/mortalidade , Material Particulado/análise , Compostos de Amônio/análise , Carbono/análise , China , Humanos , Modelos Lineares , Nitratos/análise , Sulfatos/análise
15.
J Agric Food Chem ; 67(29): 8107-8118, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31260291

RESUMO

Humic substances (HS) are vital to soil fertility and carbon sequestration. Using multiple cross-polarization/magic-angle spinning (multiCP/MAS) NMR combined with dipolar dephasing, we quantitatively characterized humic fractions, i.e., fulvic acid (FA), humic acid (HA), and humin (HM), isolated from two representative soils (upland and paddy soils) in China under six long-term (>20 years) fertilizer treatments. Results indicate that each humic fraction showed chemical distinction between the upland and paddy soils, especially with much greater aromaticity of upland HMs than of paddy HMs. Fertilizer treatment exerted greater influence on chemical natures of upland HS than of paddy HS, although the effect was less than that of soil type. Organic manure application especially decreased the percentages of aromatic C in the upland HAs and HMs compared with the control. We concluded that humic fractions responded in chemical nature to environmental conditions, i.e., soil type/cropping system/soil aeration and fertilizer treatments.


Assuntos
Substâncias Húmicas/análise , Espectroscopia de Ressonância Magnética/métodos , Solo/química , Carbono/análise , China , Fertilizantes/análise , Esterco/análise , Oryza/crescimento & desenvolvimento , Oryza/metabolismo
16.
Environ Pollut ; 253: 181-189, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31306825

RESUMO

This work explores the use of Raman micro-spectroscopy to determine sources of airborne particulate matter collected on PM2.5 air filters in Imperial Valley, California. The goal is to examine if nearby soil is a potential source of particles sampled on air filters deployed in an urbanized desert area during events of unusually high PM2.5 excursions. Particle specific composition information can be an indicator of potential origin. This can provide insights into the source of unexpectedly high proportion of large particles sampled on PM2.5 filters in the vicinity of Imperial Valley. The measured spectral correspondence between the filter and soil particles, in the size range of 2.5-10 µm, is consistent with windblown dust being a likely source of the larger (>2.5 µm) particles collected on the PM2.5 filters. Additionally, these particles were identified as components of commonly occurring crustal minerals in the vicinity of the sampling site, such as iron oxides, hydroxides, sulfides, titanium dioxides and aluminosilicates. A substantial portion of the analyzed filter particles displayed a strong broadband fluorescence signal, which is consistent with the presence of organic matter and has been recognized as a marker for soil related origin of the filter particles. Elemental carbon (soot) was found to be prevalent among the particles as well, suggesting the existence of combustion related sources. Comparison between a heavily loaded filter sample and a filter with a more typical, lower loading did not show any obvious difference in chemical compositions. In both cases the particles appeared to be of crustal origin with the prevalence of elemental carbon. The primary difference between these two filter samples appear to be their particle size distribution - the heavily loaded filter sample contained greater proportion of large particles (>2.5 µm), and was more consistent with spectral signature of soils analyzed from the region.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Material Particulado/análise , Solo , Filtros de Ar , Poluição do Ar/análise , Poluição do Ar/estatística & dados numéricos , California , Carbono/análise , Poeira/análise , Tamanho da Partícula , Análise Espectral
17.
Environ Pollut ; 253: 930-938, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31351301

RESUMO

The imprints of fireworks displays on the adjacent water body were investigated from the perspective of cogeneration of black carbon, metals and perchlorate (ClO4-). In particular, the mixing and dissipation of ClO4- were studied at Oak Lake, Lincoln, Nebraska, following fireworks displays in 2015 and 2016. Following the display, ClO4- concentration in the water increased up to 4.3 µg/L and 4.0 µg/L in 2015 and 2016, respectively. A first-order model generally provided a good fit to the measured perchlorate concentrations from which the rate of dissipation was estimated as 0.07 d-1 in 2015 and 0.43 d-1 in 2016. SEM images show imprints of soot and metal particles in aerosol samples. EDS analysis of the lake sediment confirmed the presence of Si, K, Ca, Zn and Ba, most of which are components of fireworks. The δ13C range of -7.55‰ to -9.19‰ in the lake water system closely resembles fire-generated carbon. Cogeneration of black carbon and metal with perchlorate was established, indicating that ClO4- is an excellent marker of fireworks or a burning event over all other analyzed parameters. Future microcosmic, aggregation and column-based transport studies on black carbon in the presence of perchlorate and metals under different environmental conditions will help in developing transport and fate models for perchlorate and black carbon particles.


Assuntos
Monitoramento Ambiental , Percloratos/análise , Fuligem/química , Poluentes Químicos da Água/análise , Carbono/análise , Lagos/química , Metais/análise , Nebraska , Percloratos/química , Quercus , Fuligem/análise
18.
Ying Yong Sheng Tai Xue Bao ; 30(6): 1885-1892, 2019 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-31257760

RESUMO

Carbon density is one of the important indicators for carbon sequestration capacity in forest ecosystems. The analysis of spatial variation in forest carbon density can provide scientific basis for management of forest carbon sink. We investigated the carbon density of Pinus massoniana forest in Jiangxi Province. Based on plot investigation and meaurement of sample carbon content, the spatial autocorrelation and distribution of carbon density were analyzed and explored respectively by using global Moran I, local Moran I and geostatistics. Results from the global Moran I showed that ecosystem carbon density had significant positive spatial autocorrelation and its autocorrelation decreased with the increase of distance. Ecosystem carbon density had no spatial autocorrelation when the distance exceeded 400 km. The spatial distribution of ecosystem carbon density changed from aggregated distribution to random distribution with the increase of distance. Results from the local Moran I showed that the local spatial distribution of ecosystem carbon density was not uniform, and the difference of local spatial distribution gradually increased with the increase of distance. The fitting results of semi-variogram models showed that the spherical model was the best fitting model for the estimation of ecosystem carbon density. The ratio of nugget to sill was 0.36, indicating mode-rate spatial correlation of carbon density. The ecosystem carbon density based on kriging spatial interpolation mainly concentrated in the range of 85.14-153.52 t·hm-2. The spatial distribution regularity was generally low in middle region and high in peripheral region, which was consistent with the terrain characteristics of the study area.


Assuntos
Carbono/análise , Monitoramento Ambiental , Florestas , Pinus/química , China , Ecossistema , Solo , Árvores
19.
Ying Yong Sheng Tai Xue Bao ; 30(6): 1927-1935, 2019 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-31257765

RESUMO

With the 14-year enclosed grassland and the grazed grassland as control, the impacts of anthropogenic shrublands (Caragana korshinskii) with the different planting years (3, 12, 22 a) and planting spaces (2, 8, 40 m) on soil organic carbon (SOC) contents were examined in the desert steppe of Eastern Ningxia, China. We further analyzed the spatial pattern and heterogeneity of SOC in 0-40 cm soil layer of the grassland area with introduced shrubs. The results showed that SOC in C. korshinskii shrublands had an increase trend with increased planting years and decreased spaces. The mean SOC with different planting years and spaces was 42.7% and 32.8% more than that in grazing land, respectively. There was no significant difference of SOC between shrublands and the 14-year enclosed grassland. The increase trend of SOC decreased by 27.0% in 22-year planting shrubland. The SOC content of 0-40 cm soil layer varied from 0.21 g·kg-1 to 26.04 g·kg-1 (with a mean of 3.75 g·kg-1), and the coefficient of SOC variation ranged from 90.9% to 114.7%. The SOC in 0-5 cm and 15-40 cm soil layers fitted the optimal theory formulation of Gaussian model, while that in 5-15 cm soil layer fitted a spherical model. The ranges (A0) of spatial autocorrelation in the 0-5 and 5-15 cm soil layers were smaller (3.11, 3.00 km) than that in 15-40 cm soil layer (10.10 km). The nugget/sill C0/(C0+C) of SOC in 0-5, 5-15 cm soil layer was 0.2% and 16.3%, indicating a strong spatial correlation, while that in 15-40 cm soil layer was 36.9%, with a moderate correlation. The shrub introdution could significantly accelerate the accumulation and fixation of SOC in top 40 cm soil layer in degraded desert steppe, but also intensified the spatial heterogeneity and SOC fragmentation. The SOC content in the anthropogenic shrublands had no significant difference from that in the enclosed desert steppe (14 years). The SOC spatial heterogeneity and the degree of fragmentation were weakened and decreased with the increasing soil layer depth.


Assuntos
Caragana/crescimento & desenvolvimento , Carbono/análise , Solo/química , China , Clima Desértico , Análise Espacial
20.
Environ Sci Pollut Res Int ; 26(24): 24380-24394, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31230232

RESUMO

Economic policy uncertainty (EPU) will affect the external business environment of economic entities, which in turn affects the decision-making of economic entities. Meanwhile, carbon emissions are closely related to the production decisions of microeconomic entities. Thus, studying the relationship between EPU and carbon emissions helps to clarify the impact of institutional factors behind carbon emissions, which is significant for achieving green development. Based on US sector data, we apply a novel parametric test of Granger causality in quantiles to analyze the relationship between EPU and carbon emissions (its growth and uncertainty). We find that there is an outstanding pattern of Granger-causality from the US EPU to the growth of carbon emissions in the tails of the growth distributions of carbon emissions in the industrial sector, residential sector, electric power sector, and transportation sector, except in the commercial sector. That is, carbon emissions are affected by EPU when the growth of carbon emissions is in a higher or lower growth period. Lastly, we find that the US EPU affects carbon emissions uncertainty over the entire conditional distribution for all sectors.


Assuntos
Carbono/análise , Economia , Poluição Ambiental/legislação & jurisprudência , Dióxido de Carbono/análise , Comércio , Desenvolvimento Econômico , Poluição Ambiental/economia , Indústrias , Transportes , Incerteza , Estados Unidos
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