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Potential phytomanagement of military polluted sites and biomass production using biofuel crop miscanthus x giganteus النص الكامل
2019
Pidlisnyuk, Valentina | Erickson, Larry | Stefanovska, Tatyana | Popelka, Jan | Hettiarachchi, Ganga | Davis, Lawrence | Trögl, Josef
This study aims to summarize results on potential phytomanagement of two metal(loid)-polluted military soils using Miscanthus x giganteus. Such an option was tested during 2-year pot experiments with soils taken from former military sites in Sliač, Slovakia and Kamenetz-Podilsky, Ukraine. The following elements were considered: As, Cu, Fe, Mn, Pb, Sr, Ti, Zn and Zr. M. x giganteus showed good growth at both military soils with slightly higher maximum shoot lengths in the second year of vegetation. Based on Principal Component Analysis similarities of metal(loid) uptake by roots, stems and leaves were summarized. Major part of the elements remained in M. x giganteus roots and rather limited amounts moved to the aerial parts. Levels taken up decreased in the second vegetation year. Dynamics of foliar metal(loid) concentrations divided the elements in two groups: essential elements required for metabolism (Fe, Mn, Cu, and Zn) and non-essential elements without any known metabolic need (As, Sr, Ti, and Zr). Fe, Mn, Ti and Sr showed similar S-shaped uptake curve in terms of foliar concentrations (likely due to dilution in growing biomass), while Cu exhibited a clear peak mid-season. Behavior of Zn was in between. Foliar Zr and As concentrations were below detection limit. The results illustrated a good potential of M. x giganteus for safely growing on metal-polluted soils taken from both military localities.
اظهر المزيد [+] اقل [-]What is the most ecologically-meaningful metric of nitrogen deposition? النص الكامل
2019
Payne, Richard J. | Campbell, Claire | Britton, Andrea J. | Mitchell, R. J. (Ruth J.) | Pakeman, R. J. (Robin J.) | Jones, Laurence | Ross, L. C. (Louise C.) | Stevens, Carly J. | Field, Christopher | Caporn, Simon J.M. | Carroll, Jacky | Edmondson, Jill L. | Carnell, Edward J. | Tomlinson, Sam | Dore, Anthony J. | Dise, Nancy | Dragosits, Ulrike
Nitrogen (N) deposition poses a severe risk to global terrestrial ecosystems, and managing this threat is an important focus for air pollution science and policy. To understand and manage the impacts of N deposition, we need metrics which accurately reflect N deposition pressure on the environment, and are responsive to changes in both N deposition and its impacts over time. In the UK, the metric typically used is a measure of total N deposition over 1–3 years, despite evidence that N accumulates in many ecosystems and impacts from low-level exposure can take considerable time to develop. Improvements in N deposition modelling now allow the development of metrics which incorporate the long-term history of pollution, as well as current exposure. Here we test the potential of alternative N deposition metrics to explain vegetation compositional variability in British semi-natural habitats. We assembled 36 individual datasets representing 48,332 occurrence records in 5479 quadrats from 1683 sites, and used redundancy analyses to test the explanatory power of 33 alternative N metrics based on national pollutant deposition models. We find convincing evidence for N deposition impacts across datasets and habitats, even when accounting for other large-scale drivers of vegetation change. Metrics that incorporate long-term N deposition trajectories consistently explain greater compositional variance than 1–3 year N deposition. There is considerable variability in results across habitats and between similar metrics, but overall we propose that a thirty-year moving window of cumulative deposition is optimal to represent impacts on plant communities for application in science, policy and management.
اظهر المزيد [+] اقل [-]Biomass burning source identification through molecular markers in cryoconites over the Tibetan Plateau النص الكامل
2019
Li, Quanlian | Wang, Ninglian | Barbante, Carlo | Kang, Shichang | Callegaro, Alice | Battistel, Dario | Argiriadis, Elena | Wan, Xin | Yao, Ping | Pu, Tao | Wu, Xiaobo | Han, Yu | Huai, Yanping
Cryoconite is a dark, dusty aggregate of mineral particles, organic matter, and microorganisms transported by wind and deposited on glacier surfaces. It can accelerate glacier melting and alter glacier mass balances by reducing the surface albedo of glaciers. Biomass burning in the Tibetan Plateau, especially in the glacier cryoconites, is poorly understood. Retene, levoglucosan, mannosan and galactosan can be generated by the local fires or transported from the biomass burning regions over long distances. In the present study, we analyzed these four molecular markers in cryoconites of seven glaciers from the northern to southern Tibetan Plateau. The highest levels of levoglucosan and retene were found in cryoconites of the Yulong Snow Mountain and Tienshan glaciers with 171.4 ± 159.4 ng g⁻¹ and 47.0 ± 10.5 ng g⁻¹ dry weight (d.w.), respectively. The Muztag glacier in the central Tibetan Plateau contained the lowest levels of levoglucosan and retene with mean values of 59.8 ng g⁻¹ and 0.4 ± 0.1 ng g⁻¹ d.w., respectively. In addition, the vegetation changes and the ratios of levoglucosan to mannosan and retene indicate that combustion of conifers significantly contributes to biomass burning of the cryoconites in the Yulong Snow Mountain and Tienshan glacier. Conversely, biomass burning tracers in cryoconites of Dongkemadi, Yuzhufeng, Muztag, Qiyi and Laohugou glaciers are derived from the combustion of different types of biomass including softwood, hardwood and grass.
اظهر المزيد [+] اقل [-]Urban vegetation and particle air pollution: Experimental campaigns in a traffic hotspot النص الكامل
2019
Gómez-Moreno, F.J. | Artíñano, B. | Ramiro, EDíaz | Barreiro, M. | Núñez, L. | Coz, E. | Dimitroulopoulou, C. | Vardoulakis, S. | Yagüe, C. | Maqueda, G. | Sastre, M. | Román-Cascón, C. | Santamaría, J.M. | Borge, R.
This work presents the main results of two experimental campaigns carried out in summer and winter seasons in a complex pollution hotspot near a large park, El Retiro, in Madrid (Spain). These campaigns were aimed at understanding the microscale spatio-temporal variation of ambient concentration levels in areas with high pollution values to obtain data to validate models on the effect of urban trees on particulate matter concentrations.Two different measuring approaches have been used. The first one was static, with instruments continuously characterizing the meteorological variables and the particulate matter concentration outside and inside the park. During the summer campaign, the particulate matter concentration was clearly influenced by a Saharan dust outbreak during the period 23 June to 10 July 2016, when most of the particulate matter was in the fraction PM₂.₅₋₁₀. During the winter campaign, the mass concentrations were related to the meteorological conditions and the high atmospheric stability.The second approach was a dynamic case with mobile measurements by portable instruments. During the summer campaign, a DustTrak instrument was used to measure PM₁₀ and PM₂.₅ in different transects close to and inside the park at different distances from the traffic lane. It was observed a decrease in the concentrations up to 25% at 20 m and 50% at 200 m. High PM₁₀ values were linked to dust resuspension caused by recreational activities and to a Saharan dust outbreak. The highest PM values were measured at the Independencia square, an area with many bus stops and high traffic density. During the winter campaign, three microaethalometers were used for Black Carbon measurement. Both pollutants also showed a reduction in their concentrations when moving towards inside the park. For PM₁₀ and PM₂.₅, reductions up to 50% were observed, while for BC this reduction was smaller, about 20%.
اظهر المزيد [+] اقل [-]Vehicle emissions and fertilizer impact the leaf chemistry of urban trees in Salt Lake Valley, UT النص الكامل
2019
Cobley, L.A.E. | Pataki, D.E.
The urban nitrogen (N) and carbon (C) cycles are substantially influenced by human activity. Alterations to these cycles include increased inputs from fossil fuel combustion and fertilizer use. The leaf chemistry of urban trees can be used to distinguish between these different N and C sources. Here, we evaluated relationships between urban vegetation and different N and C sources in street and residential trees in the Salt Lake Valley, Utah. We tested three hypotheses: 1) unfertilized street trees on high traffic density roads will have higher leaf %N, more enriched δ¹⁵N and more depleted δ¹³C than unfertilized street trees on low traffic density roads; 2) trees in high income residential neighborhoods will have higher leaf %N, more depleted δ¹⁵N and more enriched δ¹³C than trees in lower income neighborhoods; and 3) unfertilized street trees will have lower leaf %N, more enriched δ¹⁵N and more depleted δ¹³C than fertilized residential trees. Leaf δ¹⁵N was more enriched near high traffic density roads for one study species. However, street tree δ¹⁵N and δ¹³C were largely influenced by vehicle emissions from primary and secondary roads within 1000 m radius rather than the immediately adjacent road. Leaf δ¹³C was correlated with neighborhood income, although this relationship may be the result of variations in irrigation practices rather than variations in C sources. Finally, unfertilized trees in downtown Salt Lake had lower leaf %N, more enriched δ¹⁵N and more depleted δ¹³C than fertilized trees. These results highlight that urban trees can serve as biomonitors of the environment. Moreover, they emphasize that roads can have large spatial footprints and that the leaf chemistry of urban vegetation may be influenced by the spatial patterns in roads and road densities at the landscape scale.
اظهر المزيد [+] اقل [-]Relative effects of wind-induced disturbances and vegetation on tetrabromobisphenol A cycling in shallow lakes: Direct and indirect effects النص الكامل
2019
Cheng, Haomiao | Hua, Zulin | Wang, Liang | Wang, Yulin | Xie, Zhengxin | Zhu, Tengyi
The environmental concerns regarding the possible threats of tetrabromobisphenol A (TBBPA) to aquatic environments are increasing. However, information about TBBPA cycling in the water-vegetation-sediment systems of shallow lakes is limited. In a shallow lake, wind-induced disturbance is considered as the key factor of affecting the cycling of contaminants. To address this issue, the TBBPA distribution and elimination processes were simulated for three typical wind speeds by using an annular flume. Four forms of TBBPA were studied in these systems, including water, suspended solids (SS), vegetation and sediment. The results showed that the mass distributions of TBBPA in water, SS and vegetation increased remarkably while enhancing the wind-induced disturbances, which resulted from the release of TBBPA from the sediment through resuspension and adsorption-desorption processes. However, most of the TBBPA (up to 94%) still accumulated in the sediment. Wind-induced disturbances and vegetation both increased the TBBPA elimination rate in the water-vegetation-sediment systems. The half-life (T₁/₂) of TBBPA in the fast wind condition was 16.1 ± 0.2 days, which was shorter than that in the static condition (29.8 ± 0.9 days). Compared to the systems without vegetation, the presence of vegetation shortened the T₁/₂ by 7.3 days in the static condition. Furthermore, a structural equation model (SEM) was used to assess the direct and indirect effects of environmental factors on the TBBPA amounts in each form. The main effects of wind speed and vegetation in the TBBPA cycling of each form (except for the TBBPA on vegetation) were indirect by affecting the dissolved oxygen (DO), velocity and suspended solids concentration (SSC). Overall, the findings provide useful information about the fate of TBBPA and other related organic contaminants in shallow lake systems.
اظهر المزيد [+] اقل [-]Environmental pollution and geo-ecological risk assessment of the Qhorveh mining area in western Iran النص الكامل
2019
Saedpanah, Safoura | Amanollahi, Jamil
In order to evaluate the effect of mining activity on the environment of the Qhorveh mining area in the west of Iran, the geological, ecological and environmental data, related to social development and regional economic status, were used. The geological data included seven sub-indices, such as vegetation coverage, land utilization type, and fault activity; ecological data, with two sub-indices, such as degree of ecological environment recovery; and finally, environmental data, with three sub-indices, such as soil and dust pollutions. These were selected based on the literature and expert opinion which were utilized for environmental pollution and geo-ecological (EPGE) risk assessment of the study site. Remote sensing (RS) image, field sampling, digital elevation map, and data retrieved from different government agencies were used to generate layers for the sub-indices in the geographic information system (GIS) environment. In addition, the analytical hierarchy process (AHP) method was used to determine the weight of sub-indices. Five levels consisting of best, good, middle, poor and worst were used to describe the EPGE risk assessment of the Qhorveh mining area. Results showed that worst and poor levels of EPGE risk are in the east and northeast of the study area where the gold and pumice mines are located while best and good levels of EPGE risk are in its center where the stone mines are located. According to the results of this research, the EPGE risk assessment of the Qhorveh mining area is affected by the environmental pollution index with its highest weight (0.3908). It can be concluded that the integration of the RS, GIS and AHP methods proposed in this study improved the evaluation quality of EPGE risk assessment.
اظهر المزيد [+] اقل [-]Impacts of nitrogen deposition on carbon and nitrogen cycling in alpine Racomitrium heath in the UK and prospects for recovery النص الكامل
2019
Britton, Andrea J. | Gibbs, Sheila | Fisher, Julia M. | Helliwell, Rachel C.
Deposition of reactive nitrogen (N) is a major threat to terrestrial ecosystems associated with impacts on ecosystem properties and functions including carbon (C) and nutrient stocks, soil water quality and nutrient retention. In the oceanic-alpine Racomitrium heath habitat, N deposition is associated with moss mat degradation and a shift from bryophyte to graminoid dominance. To investigate the effects of moss mat decline on C and N stocks and fluxes, we collected Racomitrium heath vegetation/soil cores from sites along a gradient of N deposition in the UK. Cores were maintained under controlled conditions and exposed to scenarios of current (8–40 kg N ha⁻¹ y⁻¹), reduced (8 kg N ha⁻¹ y⁻¹) and elevated (50 kg N ha⁻¹ y⁻¹) N deposition. Cores from high N deposition sites had smaller aboveground C and N stocks and, under current conditions, leached large amounts of inorganic N and had low soil water pH compared with low N deposition sites. With reduced N deposition there was evidence for rapid recovery of soil water quality in terms of reduced N leaching and small increases in pH. Under high N deposition, cores from low N deposition sites retained much of the applied N while those with a history of high N deposition leached large amounts of inorganic N. Carbon fluxes in soil water and net CO₂ fluxes varied according to core source site but were not affected by the N deposition scenarios. We conclude that C and N stocks and cycling in Racomitrium heath are strongly affected by long-term exposure to N deposition but that soil water quality may improve rapidly, if N deposition rates are reduced. The legacy of N deposition impacts on moss mat cover and vegetation composition however, mean that the ecosystem remains sensitive to future pulses in N input.
اظهر المزيد [+] اقل [-]Fluorine in vegetation due to an uncontrolled release of gaseous fluorides from a glassworks: A case study of measurement uncertainty, dispersion pattern and compliance with regulation النص الكامل
2019
Štepec, Dona | Tavčar, Gašper | Ponikvar-Svet, Maja
This study was initiated after the appearance of chlorotic and necrotic lesions on vegetation in the vicinity of a glassworks. The aim was to establish whether the cause was an uncontrolled release of gaseous fluorides. Five different plant species (Norway spruce, peach, common hornbeam, common bean, common grape vine) were collected in the influenced area, and the fluorine (F) content was determined by a fluoride ion selective electrode after prior total sample decomposition by alkaline carbonate fusion. The measurement results were reported together with their measurement uncertainties (MUs), which were evaluated according to the Guide to the Expression of Uncertainty in Measurement. The F contents at comparable distances from the emitter and in a clean area, free from natural or anthropogenic fluoride emissions, were 87–676 and 10 μg g⁻¹, respectively, thereby confirming the release of gaseous fluorides from the glassworks. The F contents in samples of Norway spruce taken at various radial distances from the emitter suggest that the emitted gaseous fluorides were spread about evenly in all directions from the source following an inverse-power function. Estimated distances at which the F content would decrease to 50 μg g⁻¹ (allowed maximum content of F in feeding stuffs) and 21 μg g⁻¹ (maximum fluoride content in vegetables and fruits in relation to the upper limit of fluoride intake for humans) were 378 m and 571 m, respectively, from the emitter. Evaluation of our results for compliance with specification revealed a lack of regulation on fluoride content in the diet of humans and animals as well as a lack of guidelines on how to take into account MU.
اظهر المزيد [+] اقل [-]Seasonal and diurnal characteristics of carbonyls in the urban atmosphere of Changsha, a mountainous city in south-central China النص الكامل
2019
Jiang, Zhaohui | Zheng, Xuan | Zhai, Haiqing | Wang, Yujiao | Wang, Qiong | Yang, Zhishu
Seasonal and diurnal variations of carbonyl compounds were investigated in the ambient air of a mountainous city in China, from September 2014 to July 2015. The most abundant carbonyl compounds are formaldehyde, acetaldehyde and acetone, propionaldehyde and methacryladehyde (MACR), which were all measured in most samples. The average concentrations of formaldehyde, acetaldehyde, acetone, propionaldehyde and MACR in the atmosphere in Changsha were broken down into each season: 6.57, 3.29, 3.66, 0.67 and 0.54 μg/m³ respectively during Spring, 14.09, 8.28, 9.02, 1.28 and 0.6 μg/m³, respectively during Summer, 9.24, 5.48, 8.62, 0.73 and 0.62 μg/m³, respectively during Autumn, and 5.88, 4.84, 7.84, 0.87 and 0.26 μg/m³ respectively during Winter. And majority of the species had higher concentration during noon, showing photochemical oxidation and human activities played an important role in diurnal variation. The highest average C1/C2 (formaldehyde/acetaldehyde) ratio was observed in summer (2.10) compared to those (1.33–2.03) in other seasons, implying the photochemical activities had a positive effect on increasing the ratio of C1/C2. In this study, the monthly concentration of formaldehyde produced from isoprene accounts for 4.8%–39.1% of formaldehyde in ambient air. Strong correlation among some carbonyl compounds means that they came from the same sources. Photochemical reaction was the main source of carbonyl compounds in summer and vehicular exhaust (gasoline and diesel engines) in winter. Changsha is not a completely urbanized city and it is rich in vegetation of broadleaf evergreen shrubs. Both atmospheric photochemical reactions and anthropogenic sources, including vehicular exhaust and industrial processes, dominate the levels of carbonyls. The ILTCR and HQ values of formaldehyde and acetaldehyde are 1.23E-04 and 1.34E-05, 2.80E-01 and 1.86E-01, respectively.
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