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Forests under climate change and air pollution: Gaps in understanding and future directions for research
2012
Matyssek, R. | Wieser, G. | Calfapietra, C. | de Vries, W. | Dizengremel, P. | Ernst, D. | Jolivet, Y. | Mikkelsen, T.N. | Mohren, G.M.J. | Le Thiec, D. | Tuovinen, J.-P. | Weatherall, A. | Paoletti, E.
Forests in Europe face significant changes in climate, which in interaction with air quality changes, may significantly affect forest productivity, stand composition and carbon sequestration in both vegetation and soils. Identified knowledge gaps and research needs include: (i) interaction between changes in air quality (trace gas concentrations), climate and other site factors on forest ecosystem response, (ii) significance of biotic processes in system response, (iii) tools for mechanistic and diagnostic understanding and upscaling, and (iv) the need for unifying modelling and empirical research for synthesis. This position paper highlights the above focuses, including the global dimension of air pollution as part of climate change and the need for knowledge transfer to enable reliable risk assessment. A new type of research site in forest ecosystems (“supersites”) will be conducive to addressing these gaps by enabling integration of experimentation and modelling within the soil-plant-atmosphere interface, as well as further model development.
اظهر المزيد [+] اقل [-]Differences between carbon dioxide levels over suburban and rural sites in Northern Spain
2012
García, Ma Ángeles | Sánchez, Ma Luisa | Pérez, Isidro A.
PURPOSE: A comparison between suburban and rural atmospheric carbon dioxide concentrations in Northern Spain is made. METHOD: Measurements were carried out from April 2006 to November 2007 using MIR 9000 continuous analyzers based on the infrared technique. Two locations were established: a suburban site in Valladolid, a medium-sized city, and a rural location at CIBA, approximately 24 km northwest of Valladolid. RESULTS AND CONCLUSIONS: Mean suburban CO2 concentrations are 4.5 ppm higher than rural levels. Frequencies of suburban concentrations from 400 to 450 ppm were around twice the rural frequencies. The suburban daily evolution presented two maxima in the predawn hours and at 1900–2000 GMT, mainly associated to anthropogenic emissions which also affected maximum concentrations recorded in autumn–winter and minimum levels in summer. The rural variation with minimum values during the day and high levels at night is mainly related to vegetation activity which also impacts the highest CO2 concentrations obtained in spring, coinciding with maximum vegetation growth. Boundary layer processes also affected variability of concentrations recorded at both sites. Air quality at the rural site was also influenced by air mass transport from the urban plume (S, SSE, and ESE), which had a mean CO2 value of 402 ppm. By contrast, concentrations were low when SW–W and NW winds prevailed and brought cleaner air. The relationship between rural CO2 concentrations and wind speed using a mathematical fit provides a valuable estimation of the background level at the site, 384.8 ppm.
اظهر المزيد [+] اقل [-]Photocatalytic degradation of gaseous toluene by using immobilized titania/silica on aluminum sheets
2012
Tasbihi, Minoo | Kete, Marko | Raichur, Ashok M. | Tušar, Nataša Novak | Štangar, Urška Lavrenčič
PURPOSE: The aim of this study was to prepare a highly active immobilized titania/silica photocatalyst and to test its performance in situ toward degradation of toluene as one of the major toxic indoor contaminants. METHODS: In this work, two different titania layers immobilized on Al sheets were synthesized via low temperature sol–gel method employing presynthesized highly active titania powders (Degussa P25 and Millennium PC500, mass ratio 1:1): (a) with a silica/titania binder and a protective layer and (b) without the binder. The photocatalysts were characterized by X-ray diffraction, nitrogen sorption measurements, scanning electron microscopy (SEM), infrared spectroscopy, and UV–vis diffuse reflectance spectroscopy (DRS). The in situ photocatalytic degradation of gaseous toluene was selected as a probe reaction to test photocatalytic activity and to verify the potential application of these materials for air remediation. RESULTS: Results show that nontransparent highly photocatalytically active coatings based on the silica/titania binder and homogeneously dispersed TiO2 powders were obtained on the Al sheets. The crystalline structure of titania was not altered upon addition of the binder, which also prevented inhomogeneous agglomeration of particles on the photocatalyst surface. The photoactivity results indicate that the adsorption properties and photocatalytic activity of immobilized photocatalysts with the silica/titania binder and an underlying protective layer were very effective and additionally, they exhibited considerably improved adhesion and uniformity. CONCLUSION: We present a new highly photocatalytically active immobilized catalyst on a convenient metallic support, which has a potential application in an air cleaning device.
اظهر المزيد [+] اقل [-]Quantitative structure-retention relationship for retention behavior of organic pollutants in textile wastewaters and landfill leachate in LC-APCI-MS
2012
Noorizadeh, Hadi | Farmany, Abbas
INTRODUCTION: A quantitative structure-retention relation (QSRR) study was conducted on the retention times of organic pollutants in textile wastewaters and landfill leachate which was obtained by liquid chromatography-reversed phase-atmospheric pressure chemical ionization-mass spectrometry. METHODS: The genetic algorithm was used as descriptor selection and model development method. Modeling of the relationship between selected molecular descriptors and retention time was achieved by linear (partial least square) and nonlinear (Levenberg-Marquardt artificial neural network, L-M ANN) methods. Linear and nonlinear models provide good results whereas more accurate results were obtained by the L-M ANN model. CONCLUSION: This is the first research on the QSRR of the organic pollutants in textile wastewaters and landfill leachate against the retention time.
اظهر المزيد [+] اقل [-]Triclosan—the forgotten priority substance?
2012
von der Ohe, Peter Carsten | Schmitt-Jansen, Mechthild | Slobodnik, Jaroslav | Brack, Werner
INTRODUCTION: Triclosan (TCS) is a multi-purpose biocide. Its wide use in personal care products (PCPs) fosters its dispersal in the aquatic environment. Despite enhanced awareness of both scientists and the public in the last decade with regard to fate and effects, TCS received little attention regarding its prioritisation as a candidate river basin-specific pollutant or even priority substance, due to scarce monitoring data. METHODS: Applying a new prioritisation methodology, the potential risk of TCS was assessed based on a refined hazard assessment and occurrences at 802 monitoring sites in the Elbe River basin. RESULTS: The suggested acute-based predicted no-effect concentration (PNEC) of 4.7 ng/l for the standard test species Selenastrum capricornutum was in good agreement with effect concentrations in algal communities and was exceeded in the Elbe River basin at 75% of the sites (limit of quantification of 5 ng/l). The 95th percentile of the maximum environmental concentrations at each site exceeded the PNEC by a factor of 12, indicating potential hazards for algal communities. Among 500 potential river basin-specific pollutants which were recently prioritised, triclosan ranks on position 6 of the most problematic substances, based on the Elbe River data alone. CONCLUSION: Considering the worldwide application of PCPs containing triclosan, we expect that the TCS problem is not restricted to the Elbe River basin, even if monitoring data from other river basins are scarce. Thus, we suggest to include TCS into routine monitoring programmes and to consider it as an important candidate for prioritisation at the European scale.
اظهر المزيد [+] اقل [-]An observational study on changes in biometry and generation time of Odontophora villoti (Nematoda, Axonolaimidae) related to petroleum pollution in Bizerte bay, Tunisia
2012
Boufahja, Fehmi | Hedfi, Amor | Essid, Naceur | Aïssa, Patricia | Mahmoudi, Ezzeddine | Beyrem, Hamouda
INTRODUCTION: We conducted a yearly polluted-reference sampling to assess the effects of petroleum pollution on life cycle characteristics of the meiobenthic nematode Odontophora villoti. Samples were taken every 15 days between 26 November 2004 and 25 November 2005 from two beaches of Bizerte bay (Tunisia), Rimel and Tunisian Refining Industries Company (TRIC). The latter site is located in front of the “Tunisian Refining Industries Company” runoff. DISCUSSION: When compared to the reference site, the mean body dimensions of O. villoti from the impacted site were significantly lower. The small size of affected nematodes was represented both by the length and width as a function of the life stage. It was also established that changes in lengths of body parts during molts were different between the two study sites. The low availability of oxygen from April to August seems to prevent the formation of embryos of O. villoti. Thus, two annual reproductive cycles with different durations were observed in Rimel and TRIC. Under stress, juvenile phase and egg production were generally shorter. Globally, the impact of petroleum pollution on O. villoti was expressed by a short egg-to-egg development time. CONCLUSION: Our study assessed the usefulness of life cycle characteristics (biometry and life stage durations) of O. villoti in biomonitoring, and the results are generally consistent suggesting that this species may be considered as an efficient bioindicator.
اظهر المزيد [+] اقل [-]Combination of beehive matrices analysis and ant biodiversity to study heavy metal pollution impact in a post-mining area (Sardinia, Italy)
2012
Satta, Alberto | Verdinelli, Marcello | Ruiu, Luca | Buffa, Franco | Salis, Severyn | Sassu, Antonio | Floris, Ignazio
Mining activities represent a major source of environment contamination. The aim of this study was to evaluate the use of bees and ants as bioindicators to detect the heavy metal impact in post-mining areas. A biomonitoring programme involving a combination of honeybee hive matrices analysis and ant biodiversity survey was conducted over a 3-year period. The experimental design involved three monitoring stations where repeated sampling activities focused on chemical detection of cadmium (Cd), chrome (Cr) and lead (Pb) from different matrices, both from hosted beehives (foraging bees, honey and pollen) and from the surrounding environment (stream water and soil). At the same time, ant biodiversity (number and abundance of species) was determined through a monitoring programme based on the use of pitfall traps placed in different habitats inside each mining site. The heavy metal content detected in stream water from the control station was always below the analytical limit of quantification. In the case of soil, the content of Cd and Pb from the control was lower than that of mining sites. The mean heavy metal concentrations in beehive matrices from mining sites were mainly higher than the control, and as a result of regression and discriminant analysis, forager bee sampling was an efficient environmental pollution bioindicator. Ant collection and identification highlighted a wide species variety with differences among habitats mostly associated with vegetation features. A lower variability was observed in the polluted landfill characterised by lack of vegetation. Combined biomonitoring with forager bees and ants represents a reliable tool for heavy metal environmental impact studies.
اظهر المزيد [+] اقل [-]Metal contamination of soils and plants associated with the glass industry in North Central India: prospects of phytoremediation
2012
Varun, Mayank | D’Souza, Rohan | Pratas, João | Paul, Manoj S.
INTRODUCTION: The effect of the glass industry on urban soil metal characterization was assessed in the area of Firozabad, India. A comprehensive profile of metal contamination was obtained in five zones each containing five specific sites. FINDINGS: Zn, Cd, and As showed a greater accumulation, whereas accumulation of Ni and Cu was high in limited samples. Positive correlation was found for the metal pairs Cu-Zn, Cu-Co, and Cu-Cr at P < 0.01. Moderate positive correlation was also observed between Zn-Co, Mn-Cd, Mn-As, Pb-As, and Ni-Cu at P < 0.05. Integrated contamination indices indicate that 60% of the sites were heavily contaminated while 28% were moderately contaminated. Phytoremedial potential of native flora (twenty herbs, three shrubs, and two grasses) was also assessed by analyzing their metal uptake. Individual elements displayed remarkably different patterns of accumulation in soils as well as in plants. Mn, Zn, Cu, and As were predominantly partitioned in shoots, Co and Cd in roots while Pb, Cr, and Ni almost equally between shoots and roots. Most plants exhibited capabilities in mobilizing Co, Pb, Cr, and Ni in the root zone. CONCLUSION: Potential phytoextractors include Datura stramonium and Chenopodium murale while phytostabilizers include Calotropis procera and Gnaphalium luteo-album. Poa annua showed potential in both categories. None of the species showed phytoremedial potential for Co and Ni.
اظهر المزيد [+] اقل [-]Obsolete pesticide storage sites and their POP release into the environment—an Armenian case study
2012
Dvorská, A. | Šír, M. | Honzajková, Z. | Komprda, J. | Čupr, P. | Petrlík, J. | Anakhasyan, E. | Simonyan, L. | Kubal, M.
Organochlorinated pesticides were widely applied in Armenia until the 1980s, like in all former Soviet Union republics. Subsequently, the problem of areas contaminated by organochlorinated pesticides emerged. Environmental, waste and food samples at one pesticide burial site (Nubarashen) and three former pesticide storage sites (Jrarat, Echmiadzin and Masis) were taken and analysed on the content of organochlorinated pesticides, polychlorinated dibenzo-p-dioxins and furans and dioxin-like polychlorinated biphenyls. Gradient sampling and diffusivity-based calculations provided information on the contamination release from the hot spots on a local scale. A risk analysis based on samples of locally produced food items characterised the impact of storage sites on the health of nearby residents. All four sites were found to be seriously contaminated. High pesticide levels and soil and air contamination gradients of several orders of magnitude were confirmed outside the fence of the Nubarashen burial site, confirming pesticide release. A storage in Jrarat, which was completely demolished in 1996 and contained numerous damaged bags with pure pesticides until 2011, was found to have polluted surrounding soils by wind dispersion of pesticide powders and air by significant evaporation of lindane and β-endosulfan during this period. Dichlorodiphenyltrichloroethane-contaminated eggs, sampled from hens roaming freely in the immediate surroundings of the Echmiadzin storage site, revealed a significant health risk for egg consumers above 1E−5. Although small in size and previously almost unknown to the public, storage sites like Echmiadzin, Masis and Jrarat were found to stock considerable amounts of obsolete pesticides and have a significant negative influence on the environment and human health. Multi-stakeholder cooperation proved to be successful in identifying such sites suspected to be significant sources of persistent organic pollutants.
اظهر المزيد [+] اقل [-]Eutrophication in the Yunnan Plateau lakes: the influence of lake morphology, watershed land use, and socioeconomic factors
2012
Liu, Wenzhi | Li, Siyue | Bu, Hongmei | Zhang, Quanfa | Liu, Guihua
INTRODUCTION: Lakes play an important role in socioeconomic development and ecological balance in China, but their water quality has deteriorated considerably in recent decades. In this study, we investigated the spatial–temporal variations of eutrophication parameters (secchi depth, total nitrogen, total phosphorus, chemical oxygen demand, chlorophyll-a, trophic level index, and trophic state index) and their relationships with lake morphology, watershed land use, and socioeconomic factors in the Yunnan Plateau lakes. DISCUSSION: Results indicated that about 77.8% of lakes were eutrophic according to trophic state index. The plateau lakes showed spatial variations in water quality and could be classified into high-nutrient and low-nutrient groups. However, because watersheds were dominated by vegetation, all eutrophication parameters except chlorophyll-a showed no significant differences between the wet and dry seasons. Lake depth, water residence time, volume, and percentage of built-up land were significantly related to several eutrophication parameters. Agricultural land use and social–economic factors had no significant correlation with all eutrophication parameters. Stepwise regression analyses demonstrated that lake depth and water residence time accounted for 73.8% to 87.6% of the spatial variation of single water quality variables, respectively. Redundancy analyses indicated that lake morphology, watershed land use, and socioeconomic factors together explained 74.3% of the spatial variation in overall water quality. The results imply that water quality degradation in the plateau lakes may be mainly due to the domestic and industrial wastewaters. This study will improve our understanding of the determinants of lake water quality and help to design efficient strategies for controlling eutrophication in the plateau region.
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