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1.
Zhongguo Zhong Yao Za Zhi ; 45(16): 3805-3811, 2020 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-32893574

RESUMO

To clarify the difference of soil moisture characteristics between mixed broad leaf-conifer forest soil and artificial cultivation of Notopterygium incisum, the HYPROP system and the dew point potential meter were used to determine soil water retention curves(SWRC) for samples of two horizons(i.e. 2-7 cm, 10-15 cm). The basic physical and chemical properties of soil and its water characteristic parameters were also determined. The result showed as fllows:①The bulk density of mixed coniferous-broad leaf forest soil was between 0.33 and 0.52 g·cm~(-3), significantly lower than the corresponding value of field soil(1.01-1.18 g·cm~(-3))(P<0.05), While the organic matter content was significantly higher than the corresponding value of field soil(P<0.05). ②The saturated water content(θ_s), field water holding capacity(θ_(FC)) and Water that can be effectively utilized by plants(θ_(PAC)) of mixed coniferous-broadleaved forest soil were significantly higher than the corresponding value of field soil(P<0.05), while the retained water content(θ_r) value that cannot be effectively utilized by plants was significantly lower than that of field soil(P<0.05). ③The values of structural porosity(0.13-0.24 cm~3·cm~(-3)) and Matrix porosity(0.34-0.44 cm~3·cm~(-3)) of mixed coniferous-broadleaved forest soil were higher than the corresponding values of field soil. Therefore, with low bulk density and high content of organic matter, mixed coniferous-broadleaved forest soil can store more water in soil in the form of effective water to meet the needs of plants for water, thus possibly forming high quality medicinal materials of Notopterygii Rhizoma et Radix. In conclusion, the results of this study can provide theoretical basis guidance for soil structure improvement and water management to form high quality medicinal materials in the artificial cultivation of N. incisum.


Assuntos
Apiaceae , Traqueófitas , China , Florestas , Solo , Água/análise
2.
Sci Total Environ ; 743: 140798, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32758845

RESUMO

The impacts of climate change on precipitation and the growing demand for water have increased the water risks worldwide. Water scarcity is one of the main challenges of the 21st century, and the assessment of water risks is only possible from spatially distributed records of historical climate and levels of water reservoirs. One potential method to assess water supply is the reconstruction of oxygen isotopes in rainfall. We here investigated the use of tree-ring stable isotopes in urban trees to assess spatial/temporal variation in precipitation and level of water reservoirs. We analyzed the intra-annual variation of δ13C and δ18O in the tree rings of Tipuana tipu trees from northern and southern Metropolitan Area of São Paulo (MASP), Brazil. While variation in δ13C indicates low leaf-level enrichments from evapotranspiration, δ18O variation clearly reflects precipitation extremes. Tree-ring δ18O was highest during the 2014 drought, associated with the lowest historical reservoir levels in the city. The δ18O values from the middle of the tree rings have a strong association with the mid-summer precipitation (r = -0.71), similar to the association between the volume of precipitation and its δ18O signature (r = -0.76). These consistent results allowed us to test the association between tree-ring δ18O and water-level of the main reservoirs that supply the MASP. We observed a strong association between intra-annual tree-ring δ18O and the water-level of reservoirs in the northern and southern MASP (r = -0.94, r = -0.90, respectively). These results point to the potential use of high-resolution tree-ring stable isotopes to put precipitation extremes, and water supply, in a historical perspective assisting public policies related to water risks and climate change. The ability to record precipitation extremes, and previously reported capacity to record air pollution, place Tipuana tipu in a prominent position as a reliable environmental monitor for urban locations.


Assuntos
Mudança Climática , Água/análise , Brasil , Isótopos de Carbono/análise , Cidades , Isótopos de Oxigênio/análise
3.
Bull Environ Contam Toxicol ; 105(3): 453-459, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32840649

RESUMO

In this study, organic compounds were screened in surface water collected from Xujiahe basin, China by gas chromatography-mass spectrometry (GC-MS). A total of 51 compounds were identified including 14 organochlorine pesticides (OCPs), 9 organophosphorus pesticides (OPs), 16 polycyclic aromatic hydrocarbons (PAHs) and 12 chlorobenzene (CBs). The concentrations of OCPs, PAHs and CBs were generally low. The concentrations of OCPs in Xujiahe reservoir ranged from N.D. to 35.6 ng/L, the concentrations of PAHs ranged from N.D. to 19.8 ng/L and the concentrations of CBs ranged from 10.3 to 124.6 ng/L. The Ecological Structure Activity Relationships (ECOSAR) model was employed to directly predict the integrated toxicity indexes of 51 organic pollutants. The risk quotient (RQ) values of most of the organic compounds in the water samples were acceptable for their ecological risk.


Assuntos
Monitoramento Ambiental , Poluentes Químicos da Água/análise , China , Poluentes Ambientais/análise , Cromatografia Gasosa-Espectrometria de Massas , Hidrocarbonetos Clorados/análise , Praguicidas/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Medição de Risco , Água/análise
4.
Yakugaku Zasshi ; 140(8): 1063-1069, 2020.
Artigo em Japonês | MEDLINE | ID: mdl-32741864

RESUMO

Quantitative NMR (qNMR) has been developed as an absolute quantitation method to determine the purity or content of organic compounds including marker compounds in crude drugs. The "qNMR test" has been introduced into the crude-drug section of the Japanese Pharmacopoeia (JP) for determining the purity of reagents used for the assay in the JP. In Supplement II to the JP 17th edition published in June 2019, fifteen compounds adopted qNMR test were listed as the reagents for the assay. To establish the "qNMR test" in the crude drug section of the JP, there were several problems to be solved. Previously, we reported that the handling impurity signals from reference substances and targeted marker compounds, chemical shifts of reference substances, and peak unity of signals of targeted marker compounds are important factors to conduct qNMR measurements with intended accuracy. In this study, we investigated that the hygroscopicity of reagents could cause the changes in the compounds' purity depending on increasing their water content. Twenty-one standard products used for the crude-drug test in JP were examined by water sorption-desorption analysis, and ginsenosides and saikosaponins were found to be hygroscopic. To prepare a sample solution of saikosaponin b2 for qNMR analysis, samples need to be maintained for 18 h at 25°C and 76% relative humidity; further, samples need to be weighed at the same humidity for the qNMR analysis.


Assuntos
Contaminação de Medicamentos/prevenção & controle , Higroscópicos/química , Higroscópicos/normas , Indicadores e Reagentes/normas , Espectroscopia de Ressonância Magnética/métodos , Farmacopeias como Assunto/normas , Ginsenosídeos/química , Ginsenosídeos/normas , Umidade , Japão , Ácido Oleanólico/análogos & derivados , Ácido Oleanólico/química , Ácido Oleanólico/normas , Psicoterapia Breve , Saponinas/química , Saponinas/normas , Temperatura , Água/análise
5.
Environ Sci Pollut Res Int ; 27(30): 37455-37467, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32767011

RESUMO

Slope failure is a one of major process that causes severe landform variation and environment variation, and slope failure has become a major hidden danger to human settlement and urban construction in this vast loess region. The physical model of slope failure as induced by artificial rainfall was constructed in the field, and monitored the pore water pressure (PWP), earth stress (ES), volumetric water content (VWC), electrical conductivity (EC), and temperature (T) of the soil using this physical simulation. The surface morphology of slope started to occur in the slope as a result of erosion caused by rainfall and rainwater infiltration at the beginning of the experiment; concurrently, PWP, ES, VWC, and EC were increased gradually. Meanwhile, the saturated weight of the soil rose. In the middle of the experiment, PWP, ES, VWC, and EC were increased rapidly as the artificial rainfall continued, and the ratio of soil pore the soil fell. The slope landform was obviously occurred during the experiment, when it was noted that PWP, ES, VWC, and EC of the soil rapidly decreased. Afterwards, slope failure evolved into a debris flow; eventually, the landform was entirely changed in the slope. The soil became more compact toward the end of the experiment, and PWP, ES, VWC, and EC were slowly increased; these factors indicated that the loess slope was temporarily stable. This study could potentially be used to provide the relevant parameters for numerical simulations of landform variation in loess regions, and provide reference for regional land use planning and environmental development.


Assuntos
Chuva , Movimentos da Água , China , Conservação dos Recursos Naturais , Condutividade Elétrica , Solo , Água/análise
6.
Nature ; 584(7820): 234-237, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32788738

RESUMO

Tropical soils contain one-third of the carbon stored in soils globally1, so destabilization of soil organic matter caused by the warming predicted for tropical regions this century2 could accelerate climate change by releasing additional carbon dioxide (CO2) to the atmosphere3-6. Theory predicts that warming should cause only modest carbon loss from tropical soils relative to those at higher latitudes5,7, but there have been no warming experiments in tropical forests to test this8. Here we show that in situ experimental warming of a lowland tropical forest soil on Barro Colorado Island, Panama, caused an unexpectedly large increase in soil CO2 emissions. Two years of warming of the whole soil profile by four degrees Celsius increased CO2 emissions by 55 per cent compared to soils at ambient temperature. The additional CO2 originated from heterotrophic rather than autotrophic sources, and equated to a loss of 8.2 ± 4.2 (one standard error) tonnes of carbon per hectare per year from the breakdown of soil organic matter. During this time, we detected no acclimation of respiration rates, no thermal compensation or change in the temperature sensitivity of enzyme activities, and no change in microbial carbon-use efficiency. These results demonstrate that soil carbon in tropical forests is highly sensitive to warming, creating a potentially substantial positive feedback to climate change.


Assuntos
Ciclo do Carbono , Dióxido de Carbono/análise , Florestas , Aquecimento Global , Solo/química , Clima Tropical , Retroalimentação , Ilhas , Panamá , Fatores de Tempo , Água/análise
7.
PLoS One ; 15(8): e0238042, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32841280

RESUMO

Long-term chemical fertilizer input causes soil organic matter losses, structural compaction, and changes in soil water and nutrient availability, which have been subdued in the most of dry farmland in China. The concept of "more efficiency with less fertilizer input" has been proposed and is urgently needed in current agriculture. Application of chemical fertilizer combined with organic manure (OM) could be a solution for soil protection and sustainable production of dry-land maize (Zea mays. L). Field research over three consecutive years on the Loess Plateau of China was conducted to evaluate the integrated effects of chemical fertilizer strategies and additional OM input on soil nutrients availability and water use in maize. The results showed that, after harvest, soil bulk density decreased significantly with OM application, concomitant with 11.9, 18.7 and 97.8% increases in topsoil total nitrogen, organic matter, and available phosphorus contents, respectively, compared with those under equal chemical NPK input. Water use in the 1.0-1.5 m soil profile was improved, therefore, the soil conditions were better for maize root growth, leaf area and shoot biomass of individual maize plants increased significantly with OM application. Optimized NPK strategies increased grain yield and water use efficiency by 18.5 and 20.6%, respectively, compared to only chemical NP input. Furthermore, additional OM input promoted yield and water use efficiency by 8.9 and 5.8%, respectively. Addition of OM promotes sustainable soil and maize grain productivity as well as friendly soil environmental management of dry land farming.


Assuntos
Esterco/análise , Nutrientes/metabolismo , Compostos Orgânicos/farmacologia , Solo/química , Água/análise , Zea mays/efeitos dos fármacos , Zea mays/crescimento & desenvolvimento , Biomassa , China , Fertilizantes/análise , Nitrogênio/metabolismo , Fósforo/metabolismo , Desenvolvimento Sustentável , Zea mays/metabolismo
8.
Ying Yong Sheng Tai Xue Bao ; 31(7): 2314-2322, 2020 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-32715697

RESUMO

We explored the coupling effects of water and nitrogen in furrow irrigation on the growth and absorption and utilization of water and nitrogen in young poplar trees (triploid Populus tomentosa), under three irrigation levels (W20, W33, W45; when the soil water potential of 40 cm under the ditch reaches -20, -33 and -45 kPa respectively, irrigate), four N application levels (N120, N190, N260 and N0; the fertilization amount was 120, 190, 260 and 0 kg·hm-2·a-1), and natural conditions (CK). Based on the growth status of trees, the optimal combination of irrigation level and nitrogen application rate under furrow irrigation conditions was determined. The results showed that W20N120 (high water and low fertilizer; soil water potential threshold for initiating irrigation was -20 kPa and N application rate was 120 kg·hm-2·a-1) had the strongest effect on the stand productivity, with a value of 33.37 m3·hm-2·a-1. The significant coupling effect of water and N was detected only for tree height and total individual biomass. The increase of both irrigation amount and N application rate could increase the amount of N uptake, being mainly affected by the latter. The total amount of N uptake was the highest in the W20N260 treatment and reached 112.17 kg·hm-2·a-1, being 74.0% higher than that in CK. Among all the treatments, N uptake efficiency and N fertilizer partial productivity of W20N120 were the highest and significantly higher than those of the other treatments. The N uptake efficiency of the whole plant, aboveground part, and belowground part reached 36.8%, 28.5% and 6.4% in the W20N120 treatment, and its total N partial productivity reached 221.4 kg·kg-1. The effect of irrigation amount under different water-nitrogen coupling treatments on the irrigation water use efficiency was significant. Among them, irrigation water use efficiency in W45N260 was the highest and reached 13.66 g·kg-1. W20N120 had the highest water uptake amount and efficiency, which were 13268.28 t·hm-2 and 129.4%, respectively. To achieve great benefits, adequate irrigation (-20 kPa) and relatively low N application rate (120 kg·hm-2·a-1) should be selected during the young growth of the triploid P. tomentosa.


Assuntos
Nitrogênio/análise , Populus , Irrigação Agrícola , Biomassa , Fertilizantes , Solo , Árvores , Água/análise
9.
Ying Yong Sheng Tai Xue Bao ; 31(7): 2363-2372, 2020 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-32715702

RESUMO

Precipitation is the main driving factor for hydrological cycle in rain-fed agricultural areas, which determines the water-related ecological environment and affects the evapotranspiration characteristics of crops. By analyzing the annual distribution characteristics of precipitation across different years, this study clarified the concentrated trend of precipitation in Jingning County. Based on a field experiment in 2018 and 2019, the changes of soil moisture with precipitation and the response process of orchard evapotranspiration characteristics to the annual distribution differences of precipitation were explored. The results showed that the concentration degree of precipitation was high in the study area over the years. The concentration period was mainly distributed in July and August, with the proportion of August being up to 75%. Moreover, the time of precipitation concentration period varied greatly among years. The response of soil moisture to precipitation was mainly concentrated in the 0-40 cm layer, while moisture in deep soil layer would change significantly only in response to heavy and continuous rain. Both 2018 and 2019 were water-rich years. The precipitation concentration degree in 2018 was high, and the concentration period was earlier and shorter, with the diurnal water consumption of apple trees showing a single peak with large amplitude. In 2019, the distribution of precipitation was uniform, the concentration period was late, and the diurnal water consumption showed double-peak with a small amplitude and a lagged large peak. The maximum water demand period of apple trees lasted a long time. The concentrated distribution of heavy rain in 2018 could not meet the physiological water demands of apple trees in the later period, which damaged the yield, and the utilization efficiency of precipitation decreased by 30.2% compared with 2019. In the Loess Plateau region, there is often a brief drought during the young fruit growth period, which would affect fruit quality. Therefore, water management during this period should be strengthened.


Assuntos
Chuva , Solo , Agricultura , China , Secas , Água/análise
10.
J Environ Sci (China) ; 95: 99-110, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653198

RESUMO

PM2.5 filter sampling and components measurement were conducted in autumn and winter from 2014 to 2015 at a suburban site (referred herein as "LLH site") located in the southwest of Beijing. The offline aerosol mass spectrometry (offline-AMS) analysis and positive matrix factorization (PMF) were applied for measurement and source apportionment of water-soluble organic aerosol (WSOA). Organic aerosol (OA) always dominated PM2.5 during the sampling period, especially in winter. WSOA pollution was serious during the polluted period both in autumn (31.1 µg/m3) and winter (31.9 µg/m3), while WSOA accounted for 54.4% of OA during the polluted period in autumn, much more than that (21.3%) in winter. The oxidation degree of WSOA at LLH site was at a high level (oxygen-to-carbon ratio, O/C=0.91) and secondary organic aerosol (SOA) contributed more mass ratio of WSOA than primary organic aerosol (POA) during the whole observation period. In winter, coal combustion OA (CCOA) was a stable source of OA and on average accounted for 25.1% of WSOA. In autumn, biomass burning OA (BBOA) from household combustion contributed 38.3% of WSOA during polluted period. In addition to oxygenated OA (OOA), aqueous-oxygenated OA (aq-OOA) was identified as an important factor of SOA. During heavy pollution period, the mass proportion of aq-OOA to WSOA increased significantly, implying the significant SOA formation through aqueous-phase process. The result of this study highlights the concentration on controlling the residential coal and biomass burning, as well as the research needs on aqueous chemistry in OA formation.


Assuntos
Poluentes Atmosféricos/análise , Aerossóis/análise , Pequim , Monitoramento Ambiental , Material Particulado/análise , Água/análise
11.
Environ Monit Assess ; 192(7): 478, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32613462

RESUMO

Efficient, just, and sustainable water resources' allocation is difficult to achieve in multi-stakeholder basins. This study presents a multi-objective optimization model for water resources allocation and reports its application to the Sefidrud basin in Iran. Available water resources are predicted until 2041with the artificial neural network algorithm (ANN). This is followed by multi-objective optimization of water resource allocation. The first objective function of the optimization model is maximization of revenue, and the second objective function is the achievement of equity in water resources allocation in the basin. This study considers two scenarios in the optimization scheme. The first scenario concerns the water allocation with existing dams and dams under construction. The second scenario tackles water allocation adding dams currently in the study stage to those considered in Scenario 1. The Gini coefficient is about 0.1 under the first scenario, indicating the preponderance of economic justice in the basin. The Gini coefficient is about 0.4 under the second scenario, which signals an increase of injustice in water allocation when considering the future operation of dams currently under study.


Assuntos
Recursos Hídricos , Água/análise , Monitoramento Ambiental , Irã (Geográfico) , Alocação de Recursos
12.
Chemosphere ; 259: 127396, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32645596

RESUMO

The performance of the UV/H2O2 advanced oxidation process (AOP) is dependent on water quality parameters, including the UV absorbance coefficient at 254 nm and hydroxyl radical (•OH) water background demand (scavenging factor, s-1). The •OH scavenging factor represents the •OH scavenging rate of the background substances in the water matrix, and it is known to be one of the key parameters to predict the performance of the UV/H2O2 process. The •OH scavenging factor has been determined experimentally by using a probe compound such as pCBA and rhodamine B. The experimental method has been validated to accurately predict the micropollutants removal in the UV/H2O2 process, but there is a need for an easier and simple method of determining the OH scavenging factor. We evaluated the alternative method to analyze the •OH scavenging factor using fluorescence excitation-emission matrix and parallel factor analysis (F-EEM/PARAFAC). The correlation between •OH scavenging factor and the spectroscopic characteristics and structure of different organic matter types was evaluated. Organic matter was characterized using a fluorescence excitation-emission matrix, parallel factor analysis, and liquid chromatography-organic carbon detection. Second-order reaction rates of humic acid sodium salt, sodium alginate, Suwannee River humic acid and bovine serum albumin were calculated as 1.30 × 108 M-1 s-1, 1.39 × 108 M-1 s-1, 1.03 × 108 M-1 s-1, and 3.17 × 107 M-1 s-1, respectively. Results of PARAFAC analysis, the ratio of humic and fulvic fluorescence component 2 to terrestrial humic-like fluorescence component 1 (C2/C1), and •OH scavenging factor showed high linearity. A predictive model, which combines with the F-EEM/PARAFAC method, predicted the optimal UV and H2O2 dose to achieve target compound removal.


Assuntos
Poluentes Químicos da Água/química , Purificação da Água/métodos , Análise Fatorial , Fluorescência , Substâncias Húmicas/análise , Peróxido de Hidrogênio/análise , Radical Hidroxila/química , Oxirredução , Rios/química , Espectrometria de Fluorescência/métodos , Água/análise , Poluentes Químicos da Água/análise , Qualidade da Água
13.
Chemosphere ; 260: 127555, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32673870

RESUMO

As (III) is widely distributed in groundwater which is relatively harder to be removed comparing to As (V). Co-grinding Ca(OH)2 with Al(OH)3 was conducted to manufacture katoite (Ca3Al2(OH)12) for the complete removal of As(III) (concentration below drinking water standard of WHO (<10 ppb)) during one-step agitation operation. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TG), and X-ray photoelectron spectroscopy (XPS) were applied for the illustration of adsorption mechanism. Katoite could intercalate As(III) into the layered space forming arsenite pillared Ca-Al layered double hydroxide (LDH). The coexisting anions such as Cl-, SO42-, and NO3- had minor effects on As (III) removal performance using katoite. Techno-economic analysis demonstrated the feasibility of large-scale katoite production and its practical application for As(III) polluted groundwater purification, especially in the undeveloped areas where groundwater was used as irrigation and drinking water.


Assuntos
Arsenitos/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Água Subterrânea/química , Concentração de Íons de Hidrogênio , Hidróxidos/química , Espectroscopia Fotoeletrônica , Espectroscopia de Infravermelho com Transformada de Fourier , Água/análise , Poluentes Químicos da Água/análise , Difração de Raios X
14.
J Chromatogr A ; 1625: 461295, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709338

RESUMO

In addition to the diverse extraction techniques available, capsule phase microextraction (CPME), which uses a microextraction capsule (MEC), has recently been introduced as a sorptive-based sample preparation technique. In this study, two different MECs (MEC-C18/SAX and MEC-C18/SCX) based on mixed-mode ion-exchange technology were synthesized and evaluated for the selective extraction of a group of ionizable compounds, including acidic and basic analytes. A sulfonic acid was used as the cation-exchange group in MEC-C18/SCX, and a quaternary amine as the anion-exchange group in MEC-C18/SAX. The extraction parameters optimized were sample pH, elution solvent, sample/elution volume and extraction/elution time. The optimized CPME method followed by LC-MS/MS was used to determine the ionizable compounds in environmental water samples, including river water and effluent wastewater, with excellent selectivity and matrix effect values below -30% (except -33% for mephedrone) and apparent recovery results ranging from 40% to 69%, except for ibuprofen (< 35%) and atenolol (< 25%). The analytical method was validated for environmental water samples, and used in the analysis of several samples in which some of the target compounds were found at ng L-1 concentration levels.


Assuntos
Microextração em Fase Líquida/métodos , Transição de Fase , Espectrometria de Massas em Tandem/métodos , Poluentes Químicos da Água/análise , Cromatografia Líquida , Concentração de Íons de Hidrogênio , Reprodutibilidade dos Testes , Rios/química , Extração em Fase Sólida/métodos , Fatores de Tempo , Eliminação de Resíduos Líquidos , Águas Residuárias/química , Água/análise
15.
Sci Total Environ ; 738: 139808, 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-32531596

RESUMO

The extreme climate events such as El Nino seriously threaten crop production and agro-ecological sustainability because of the aggravated environmental stresses worldwide, particularly in sub-Saharan Africa. To address this issue, we investigated the effects of dual plastic film and straw mulching in ridge-furrow (RF) system on wheat productivity, soil carbon and nitrogen stocks in a semiarid area in Kenya from 2015 to 2017. The experimental site represents a typical semiarid continental monsoon climate, and soil type is chromic vertisols. Field experiment with randomized block design consisted of six RF treatments as follows: 1) dual black plastic film and straw mulching (RFbS), 2) dual transparent plastic film and straw mulching (RFtS), 3) sole black plastic film mulching (RFb), 4) sole transparent plastic mulching RF (RFt), 5) sole straw mulching (RFS) and 6) no mulching (CK). The results indicated that seasonal dynamics of rainfall and air temperature fit in with the weather type of El Nino over four growing seasons. RFbS, RFtS, RFb and RFt significantly increased soil water storage (SWS), topsoil temperature, aboveground biomass, grain yield and water use efficiency across four growing seasons (p < 0.05) as compared with CK. Among all the treatments, RFbS and RFtS achieved the greatest SWS, AgB, grain yield and WUE, owing to improved soil hydro-thermal status in both treatments. Critically, RFbS and RFtS significantly improved soil organic carbon and total nitrogen, soil bulk density and the C:N ratio following four growing seasons, comparing with other treatments (p < 0.05). Besides, RFbS and RFtS gave the highest economic returns among all treatments. For the first time, we found that dual plastic film and straw mulching could serve as a sustainable land management to boost wheat productivity and improve soil quality under El Nino in semiarid areas of SSA.


Assuntos
Solo , Triticum , Agricultura , Carbono , China , El Niño Oscilação Sul , Quênia , Plásticos , Água/análise , Zea mays
16.
Ecotoxicol Environ Saf ; 202: 110887, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32585488

RESUMO

Chemical immobilization of heavy metals is a simple, low-cost, and environment-friendly technology for remediation of heavy metals contaminated soils. However, changes in environmental conditions, such as water management, acid deposition, temperature fluctuation, etc., might result in release of metal ions from the fixation sites, and the long-term stability of immobilization remediation is unclear. This study attempted to investigate the impact of water management strategies (wetting-drying cycle and dry cycle) on the stability of heavy metal immobilization by one-time application of biochar during 3 consecutive years of rice-wheat crop in Cu/Cd-contaminated soil. The transformation and accumulation of Cd and Cu in soil-crop system and the morphololgy and composition of biochar were analyzed. The results revealed that wetting-drying cycle and drying treatments reduced the contents of available Cd and Cu in soil by 15.9%-17.7% and 23.9%-31.5% and by 19.8%-62.7% and 16.1%-65.0%, as well as increased soil pH by 0.11-0.31 and 0.17-0.56, respectively. In the wetting-drying cycle treatment, biochar was more favorable for decrease in Cd and Cu accumulation in crop, when compared with that in dry treatment; however, the differences were insignificant in the subsequent years. Although the different water management strategies had no obvious effect on the soil total C, physicochemical analysis of the biochar collected after pot experiments indicated that the obvious structural decomposition of biochar in the drying treatment may have resulted in the release of heavy metals immobilized in biochar. These findings help in better understanding of the long-term immobilization mechanism of biochar in soil-plant system.


Assuntos
Agricultura/métodos , Cádmio/análise , Cobre/análise , Poluentes do Solo/análise , Carvão Vegetal/química , Poluição Ambiental/análise , Metais Pesados/análise , Oryza/química , Rotação , Solo/química , Triticum , Água/análise , Abastecimento de Água
17.
Chemosphere ; 257: 127186, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32516669

RESUMO

Fluoride is an element that is widely distributed in the environment. The involvement of fluoride in pathogenesis of Chronic Kidney Disease of uncertain aetiology (CKDu) in Sri Lanka is a much-debated topic. This study aimed to investigate the fluoride concentration in drinking water in CKDu affected areas in Sri Lanka and to evaluate the possible effect of renal impairment on serum fluoride levels in CKDu patients. Drinking water (n = 60) from the common water sources from two CKDu prevalent areas and serum samples of CKDu patients (n = 311) and healthy controls (n = 276) were collected. Both environmental and biological samples were analysed for the concentration of fluoride. The fluoride concentration in over 95% of drinking water samples was below the WHO guideline of 1.5 mg/L. Serum fluoride concentrations in majority of the unaffected and early-stage CKDu patients (stages 1 and 2, eGFR >60 ml/min/1.73m2) were below the normal upper concentration of 50 µg/l and significantly higher levels were observed in patients in late stages of CKDu compared to the healthy controls. The available guidelines for drinking water are solely based on healthy populations with normal renal function. But, it is evident that once the kidney function is impaired, patients enter a vicious cycle as fluoride gradually accumulates in the body, further damaging the kidney tissue. Thus, close monitoring of serum fluoride levels in CKDu patients and establishing health-based target guidelines for fluoride in drinking water for the CKDu patients are recommended to impede the progression to end stage renal disease.


Assuntos
Exposição Ambiental/estatística & dados numéricos , Fluoretos/metabolismo , Insuficiência Renal Crônica/epidemiologia , Poluentes Químicos da Água/metabolismo , Feminino , Fluoretos/análise , Taxa de Filtração Glomerular , Humanos , Masculino , Pessoa de Meia-Idade , Minerais/análise , Sri Lanka/epidemiologia , Incerteza , Água/análise , Poluentes Químicos da Água/análise
18.
PLoS One ; 15(6): e0234307, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32569328

RESUMO

We identified the key sectors of water resource use in China from the perspective of the water footprint to improve the use of water resources. The empirical results showed that there were six key sectors (including Crop Cultivation; Forestry; Livestock and Livestock Products; Fishery, Technical Services for Agriculture, Forestry, Livestock and Fishing; Other Food Products, and Scrap and Waste) for water consumption in China in 2015.We analyzed the use of green water, blue water, and grey water. These six sectors accounted for 66.15% of the total impact and 90.76% of the direct impact. Seven key sectors (the six sectors above plus Steel Processing)for the consumption of blue water in China can explain 59.70% of the total impact and 86.94% of the direct effect in 2015. Eight key sectors (Crop cultivation, Other food products, Scrap and Waste, Railway Freight Transport, Highway Freight and Passengers Transport, Water Freight and Passengers Transport, Pipeline Transport, and Health Services) responsible for the consumption of grey water in China in 2015 can explain 81.28% of the total impact and 95.73% of the direct impact. Therefore, the Chinese government should focus on the departments that manage water resources in these sectors when designing water-saving policies and improving water-use efficiency, such as promoting water-saving irrigation technology (including sprinkler irrigation and drip irrigation) in the agricultural sector.


Assuntos
Conservação dos Recursos Naturais/métodos , Recursos Hídricos/provisão & distribução , Abastecimento de Água/métodos , Irrigação Agrícola/métodos , Agricultura/métodos , China , Produtos Agrícolas , Agricultura Florestal , Água/análise
19.
Int J Syst Evol Microbiol ; 70(7): 4364-4371, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32579101

RESUMO

A novel, moderately thermophilic, Gram-stain-negative bacterium, designated strain J18T, was isolated from a water-flooded oil reservoir. Cells were aerobic, oxidase- and catalase-positive, with a polar flagellum. Growth occurred at 35-60 °C and at pH 6-8.5. The respiratory quinones were ubiquinone 8 and ubiquinone 9. The dominant cellular fatty acids were C16 : 0, C17 : 0 cyclo, C19 : 0 cyclo ω8c and summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c). The polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, an unidentified aminolipid, an unidentified phospholipid and an unidentified aminophospholipid. The strain showed the highest 16S rRNA gene sequence similarities to Tepidiphilus margaritifer DSM 15129T (98.6 %), Tepidiphilus succinatimandens DSM 15512T (98.4 %) and Tepidiphilus thermophilus DSM 27220T (98.1 %), respectively, and the similarity to other species was lower than 93 %. In the phylogenetic trees, it constituted a unique sub-cluster within the genus Tepidiphilus. The DNA G+C content of strain J18T was 64.44 mol%. As compared with the type strains, the genome-to-genome distances of strain J18T were 34.7-40 %. These results confirmed the separate species status of J18T with its close relatives. On the basis of physiological, chemotaxonomic and phylogenetic analyses along with the low levels of identity at the whole-genome level, it can be concluded that strain J18T represents a new species of the genus Tepidiphilus, for which the name Tepidiphilus olei sp. nov. is proposed. The type strain of T. olei is J18T (=CGMCC 1.16800T=LMG 31400T).


Assuntos
Hydrogenophilaceae/classificação , Campos de Petróleo e Gás/microbiologia , Filogenia , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Hydrogenophilaceae/isolamento & purificação , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/química , Água/análise
20.
PLoS One ; 15(6): e0220598, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32579545

RESUMO

Roof greening is an important national policy for maintaining the hydrological balance in China; however, plant growth is limited by drought stress. This study aims to identify strong drought resistant plant species for roof greening from ten common species: Paeonia lactiflora, Hemerocallis dumortieri, Meehania urticifolia, Iris lactea var. chinensis, Hylotelephium erythrostictum, Sedum lineare, Iris germanica, Cosmos bipinnata, Hosta plantaginea, and Dianthus barbatus. By controlling the soil relative water content (RWC), we designed three treatments: moderate drought stress (40±2% < RWC < 45±2%), severe drought stress (RWC < 30±2%) and well-watered control (RWC > 75±2%). After the seedlings were provided different levels of water, their membrane permeability (MP), chlorophyll concentration (Chl), and superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX) activity were measured. Finally, the membership function method was used to assess the drought resistance of these species. The results showed that C. bipinnata and M. urticifolia were not suitable for moderate or severe drought stress and did not survive. The other species presented variations in physiological and biochemical parameters. The MP of He. dumortieri, I. lactea and Ho. plantaginea showed minor changes between the well-watered control and drought stress. Most of the species showed reduced SOD activity under moderate drought stress but increased activity under severe stress. All of the plant species showed decreases in the protective enzymes POD and APX with increasing drought stress. The membership function method was applied to calculate the plant species' drought resistance, and the following order of priority of the roof-greening plant species was suggested: He. dumortieri > I. germanica > I. lactea > D. barbatus > Hy. erythrostictum > S. lineare > Ho. plantaginea > P. lactiflora.


Assuntos
Secas , Fenômenos Fisiológicos Vegetais , Plântula/fisiologia , Estresse Fisiológico , Ascorbato Peroxidases/metabolismo , Permeabilidade da Membrana Celular , Clorofila/metabolismo , Peroxidases/metabolismo , Plântula/metabolismo , Solo/química , Superóxido Dismutase/metabolismo , Análise de Sobrevida , Água/análise
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