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91.
The present study deals with the characterization of industrial effluents released from various industries and distribution of heavy metals in effluent discharge channel and its impact on the river Damodar. The effluent of tamlanala, a natural storm water channel, is extensively used for irrigation for growing vegetables in and around the study area. The heavy metals in water of the study area are in the order of Fe > Mn > Pb >?Cd and sediments follow similar trends too. The enrichment of heavy metals in the sediments are in the order of Cd (39.904) > Pb (33.156) > Mn (0.164) > Fe (0.013). The geoaccumulation index values reveal effluent channel is subjected to moderate to high pollution with respect to Cd (4.733) and Pb (4.466). The analyzed data for enrichment factors and the pollution load index (1.305) show that effluent channels have suffered from significant heavy metal contamination following industrialization and urbanization. Compared to baseline values, the surface sediment layers show high enrichment across the channel and at its discharge point. The factor analysis reveals three factors—industrial sources, surface runoff inputs, and background lithogenic factors which clarify the observed variance of the environmental variables. Metal pollution assessment of sediments suggests that pollution from the heavy metals observed is high in the tamlanala which in turn affects the downstream of the river system.  相似文献   
92.
In this paper two different approaches for predicting the heating-up of an acetylene cylinder involved in a fire and the afterward cooling with water are presented. In the simulations polynomial functions were used to describe the temperature dependency of the thermal properties of the cylinder interior, which is a complex system composed by a solid porous material, a solvent (typically acetone) and acetylene dissolved in it. Model equations covered heat conduction in the cylinder interior and at its walls. In the first approach the cylinder surroundings were simulated as a further domain constituted by CO2, during the fire exposure, and for water, during the cooling. In this domain the coupled heat transfer (convection and conduction) and the momentum equation (Navier–Stokes) were solved. In the second approach no further domain was considered but boundary conditions were set directly on the cylinder walls. Results of the calculations performed with both approaches are presented. This work could prove helpful in predicting to which extent the interior of an acetylene cylinder exposed to fire reaches temperatures capable of initiating the decomposition of acetylene and to determine how long a water cooling should be applied, so that the system is brought again under non-critical conditions.  相似文献   
93.
An anaerobic plume of process-affected groundwater was characterized in a shallow sand aquifer adjacent to an oil sands tailings impoundment. Based on biological oxygen demand measurements, the reductive capacity of the plume is considered minimal. Major dissolved components associated with the plume include HCO3, Na, Cl, SO4, and naphthenic acids (NAs). Quantitative and qualitative NA analyses were performed on groundwater samples to investigate NA fate and transport in the subsurface. Despite subsurface residence times exceeding 20 years, significant attenuation of NAs by biodegradation was not observed based on screening techniques developed at the time of the investigation. Relative to conservative tracers (i.e., Cl), overall NA attenuation in the subsurface is limited, which is consistent with batch sorption and microcosm studies performed by other authors. Insignificant biological oxygen demand and low concentrations of dissolved As (< 10 µg L− 1) in the plume suggest that the potential for secondary trace metal release, specifically As, via reductive dissolution reactions driven by ingress of process-affected water is minimal. It is also possible that readily leachable As is not present in significant quantities within the sediments of the study area. Thus, for similar plumes of process-affected groundwater in shallow sand aquifers which may occur as oil sands mining expands, a reasonable expectation is for NA persistence, but minimal trace metal mobilization.  相似文献   
94.
Zusammenfassung   Hintergrund, Ziel und Zweck Borkenbewohnende (epiphytische) Flechten reagieren sehr empfindlich auf verschiedene Umwelteinflüsse wie Stoffgehalte in der Atmosph?re und Temperaturen. Sie haben als Bioindikatoren für Luftverunreinigungen einen hohen Stellenwert bei Umweltuntersuchungen. Basierend auf einer 1989 durchgeführten Kartierung borkenbewohnender (epiphytischer) Flechten in einem landwirtschaftlich intensiv genutzten Raum Nordwestdeutschlands erfolgte 2007 eine Wiederholungsuntersuchung. Dabei galt es, m?gliche Ver?nderungen der Immissionssituation und des Klimas zu erkennen. Material und Methoden Die Studie basiert auf einer vergleichenden Kartierung epiphytischer Flechten von 355 Tr?gerb?umen an 45 Monitoringpunkten. Die angewandte Methode orientiert sich an der 1989 angewandten halb-quantitativen Erfassung. Ergebnisse Es stellten sich gravierende Ver?nderungen in der Vegetation rindenbewohnender Flechten heraus. Insgesamt war eine Erh?hung der Artenzahl an nahezu allen Monitoringpunkten festzustellen. Es wurde eine sehr starke Abnahme s?uretoleranter Arten und eine deutliche Zunahme basen- und n?hrstofffordernder Flechtenarten festgestellt. Darüber hinaus zeigte sich eine deutliche Zunahme w?rmeliebender Flechtenarten mit einem Verbreitungsschwerpunkt in Südeuropa bei gleichzeitigem Rückgang von Arten mit einem boreal-montanem Verbreitungsschwerpunkt. Diskussion Die festgestellte Entwicklung steht im Einklang mit überregionalen Beobachtungen. Sie wird im Wesentlichen auf eine gro?r?umig ver?nderte Immissionssituation, d. h. einer Abnahme der atmosph?rischen SO2-Belastung und Zunahme der Ammoniakbelastung zurückgeführt. Ebenso treten deutliche Auswirkungen der Klimaerw?rmung hervor. Schlussfolgerungen Mit relativ geringem Untersuchungsaufwand lie?en sich Ver?nderungen bei den epiphytischen Flechten in den letzten 18 Jahren aufzeigen. Diese sind relevant für die Beurteilung regional und kleinr?umig ver?nderter Umweltbedingungen, die auch für andere Organismen und ?kosysteme l?ngerfristig von gro?er Bedeutung sind. Empfehlungen und Ausblick Unter Verwendung standardisierter Methoden vermitteln epiphytische Flechten ein differenziertes Bild der Luftbelastungssituation in Ballungsr?umen und in landwirtschaftlich genutzten Regionen. Darüber hinaus sind sie offensichtlich gute Indikatoren für Temperatur?nderungen ihrer Umgebung. Weiterer Forschungsbedarf besteht für die Verwendung epiphytischer Flechten zum Biomonitoring von Klimaver?nderungen.   相似文献   
95.
Residence time-dependent distribution patterns of hexachlorobenzene (HCB) and dichlorodiphenyltrichloroethane (DDT) among different soil organic matter fractions of three Chinese soils were investigated. Soil organic matter (SOM) was fractionated into fulvic acid (FA), humic acid (HA), bound-humic acid (BHA), lipid, and insoluble residue (IR) fractions using methyl isobutyl ketone (MIBK) method. Results revealed that as the residence time prolonged, the amounts of HCB and DDT in the FA, HA and BHA fractions decreased, while those in the lipid and IR fractions increased. One- and two-compartment first order, and one- and two-parameter pore-diffusion kinetic models were used to describe the mobility of HCB and DDT from the FA, HA and BHA fractions. The results suggest that excellent agreements were achieved between the experimental data and fits to the two-compartment first order kinetic model (R2>0.97). The transfer rates of HCB and DDT followed the order FA>HA>BHA.  相似文献   
96.
Challenges in quantifying biosphere-atmosphere exchange of nitrogen species   总被引:2,自引:0,他引:2  
Recent research in nitrogen exchange with the atmosphere has separated research communities according to N form. The integrated perspective needed to quantify the net effect of N on greenhouse-gas balance is being addressed by the NitroEurope Integrated Project (NEU). Recent advances have depended on improved methodologies, while ongoing challenges include gas-aerosol interactions, organic nitrogen and N(2) fluxes. The NEU strategy applies a 3-tier Flux Network together with a Manipulation Network of global-change experiments, linked by common protocols to facilitate model application. Substantial progress has been made in modelling N fluxes, especially for N(2)O, NO and bi-directional NH(3) exchange. Landscape analysis represents an emerging challenge to address the spatial interactions between farms, fields, ecosystems, catchments and air dispersion/deposition. European up-scaling of N fluxes is highly uncertain and a key priority is for better data on agricultural practices. Finally, attention is needed to develop N flux verification procedures to assess compliance with international protocols.  相似文献   
97.
The disposal of fly-ash (FA) from coal-fired power stations causes significant economic and environmental problems. Use of such contaminated sites for crop production and use of contaminated water for irrigation not only decreases crop productivity but also poses health hazards to humans due to accumulation of toxic metals in edible grains. In the present investigation, three rice cultivars viz., Saryu-52, Sabha-5204, and Pant-4 were grown in garden soil (GS, control) and various amendments (10%, 25%, 50%, 75% and 100%) of FA for a period of 90 days and effect on growth and productivity of plant was evaluated vis-a-vis metal accumulation in the plants. The toxicity of FA at higher concentration (50%) was reflected by the reduction in photosynthetic pigments, protein and growth parameters viz., plant height, root biomass, number of tillers, grain and straw weight. However, at lower concentrations (10-25%), FA enhanced growth of the plants as evident by the increase of studied growth parameters. The cysteine and non-protein thiol (NP-SH) content showed increase in their levels up to 100% FA as compared to control, however, maximum content was found at 25% FA in Saryu-52 and Pant-4 and at 50% FA in Sabha-5204. Accumulation of Fe, Si, Cu, Zn, Mn, Ni, Cd and As was investigated in roots, leaves and seeds of the plants. Fe accumulation was maximum in all the parts of plant followed by Si and both showed more translocation to leaves while Mn, Zn, Cu, Ni and Cd showed lower accumulation and most of the metal was confined to roots in all the three cultivars. As was accumulated only in leaves and was not found to be in detectable levels in roots and seeds. The metal accumulation order in three rice cultivars was Fe > Si > Mn > Zn > Ni > Cu > Cd > As in all the plant parts. The results showed that rice varieties Saryu-52 and Sabha-5204 were more tolerant and could show improved growth and yield in lower FA application doses as compared to Pant-4. Thus, Sabha-5204 and Saryu-52 are found suitable for cultivation in FA amended agricultural soils for better crop yields.  相似文献   
98.
Background, aim, and scope Basically, technological innovations are associated with benefits and risks. This is also true for the introduction of genetically modified organisms (GMO) into agriculture. In Germany, precautionary regulations currently demand isolation distances (i.?e. buffer zones) for the cultivation of genetically modified maize (Bt-maize) in the vicinity of conventional (150?m) and organic maize fields (300?m). The Bt-toxin may harm non-target organisms (NTO) such as Lepidoptera. Despite this, corresponding regulations for the protection of nature reserves are lacking to date. Conventional and Bt-maize have been grown in the vicinity of the Flora-Fauna-Habitat (FFH) Ruhlsdorfer Bruch in Brandenburg, Germany. The aim of this study was to investigate whether exposure of maize pollen from surrounding Bt-maize fields to NTOs in the nature protection area could be excluded or not. Two types of exposure were investigated: Firstly, whether maize pollen was dispersed by wind into the nature reserve area exposing resident NTOs. Secondly, foraging NTOs from the nature reserve are exposed by roaming the surrounding fields and collecting maize pollen. In order to fulfil the precautionary principle defined by law, the study should help to determine appropriate isolation distances for the cultivation of Bt-maize with regard to sustainable protection of NTOs in the FFH Ruhlsdorfer Bruch. In 2007, the local authorities issued an isolation distance between Bt-maize fields and nature reserves of 100?m and in 2008, this became 250?m in the northern and 500?m in the westerly direction, respectively. Materials and methods Standardised methods for biological and technical pollen sampling issued by the Association of German Engineers (VDI 4330 Part 3, 2007 and VDI 4330 Part 4, 2006) were applied providing a quality controlled and methodologically harmonised database which does not only serve the needs to be fulfilled by the present case-specific monitoring study but can also be used as a reference database for further investigations. Maize pollen exposure was measured within the FFH Ruhlsdorfer Bruch and its immediate vicinity in July and August 2007 and 2008. In 2007, the sampling was performed at three sites using 12 technical samplers (Sigma-2/PMF) placed at five measuring points at distances from 5?m to 120?m from the maize field edges. Additionally, for biological pollen sampling six bee colonies were situated at these three sites (two colonies at each site). The technical sampler Sigma-2/PMF enables point sampling which is primarily influenced by wind and topography providing information on effective maize pollen input (flow and deposition) at the measuring sites. Honey-bees roaming in the surrounding area with typical foraging distances of several kilometres may act as planar collectors. They may serve as indicators for the exposure to pollen-collecting NTOs. Furthermore, biological sampling is more selective due to the organism’s preferences, whereas the technical sampling is neutral. Hence, both the technical and the biological sampling complement each other in their scope of application. The pollen samples of both matrices were analysed microscopically and the maize pollen loads were quantified. Pollen-DNA was analysed by means of the quantitative PCR-method (qPCR) identifying conventional and Bt-maize pollen by two independent laboratories. In 2008, the monitoring was repeated with additional sites. Eighteen technical samplers were exposed at five sites with eight measuring points at distances from 5?m to 250?m from the maize field edges. Two honey-bee colonies for biological sampling were placed at one site for control purposes. PCR-analyses were performed to measure the amounts of Bt-maize pollen in the samples. Results The results of pollen monitoring at the Ruhlsdorfer Bruch revealed maize pollen exposure for all monitoring sites in both surveys. In 2007, up to 1.75 million maize pollen/m² were deposited at sites closest to the maize field. At 120?m from field edge in the middle of the FFH-reserve, 99,000 maize pollen/m² were detected. In 2008, similar results were found, at distances up to 250?m from the field edges deposition of 164,000 maize pollen/m² was detected. Data on maize pollen deposition show a clear distance relationship and are in accordance with results of further comprehensive surveys based on the same methodology (Hofmann 2007). The results of the microscopic analysis of the pollen pellets demonstrated that bees collected maize pollen at all sites, in 2007 and 2008. Although maize pollen is not the main food source (2007:0.1–0.3?%; 2008:2–3?%) the collection efficiency of the bee colonies resulted in high amounts of sampled maize pollen with 4 to 11 million per site in 2007 and up to 467 million in 2008. Molecular-biological analysis of maize pollen DNA by qPCR demonstrated that transgenic Bt-MON810 DNA was present in all technical and biological samples, corroborated by two independent laboratories. In 2007, the GMO-content in the samples ranged up to 44?% in the bioaerosols and 49?% in the pollen pellets. In 2008, GMO-proportions of up to 18?% were detected. Discussion The results of this study provide evidence that NTOs in the Ruhlsdorfer Bruch were exposed to Bt-maize pollen under the cultivation conditions in 2007 with a buffer zone of 100?m. The GMO-content reached up to 48?%. The results of the monitoring in 2008 confirmed these findings. Even though the exposure could be reduced by increasing the isolation distances to 250?m and 500?m respectively, the results still show percentages of up to 18?% Bt-MON810 in the pollen samples. The results on maize pollen deposition at the Ruhlsdorfer Bruch in 2007 and 2008 correspond to the results of an investigation which was conducted over several years applying the same standardised method, but covering a wider range of distances. The correlation between maize pollen deposition (n/m²) and distance to the source field (m) fitted best to a power function of the type y = 1.2086 · 106 · x –0.548. Despite the same trend, the pollen deposition in the Ruhlsdorfer Bruch revealed above-average findings. Also the analysis of the pollen pellets collected by the bees showed an exposure in 2007 with values for the GMO-content of up to 49?%. For both methods, the exposure decreased in 2008 due to the greater buffer zones up to 500?m. Whereas the GMO-content for the biological sampling were reduced to values below 10?%, the values for the technical sampling were still higher indicating that greater buffer zones would be necessary for safety reasons under the precautionary principle. Conclusions The results of this investigation proved that maize pollen were dispersed by wind to distances farther than 250?m from field edge leading to maize pollen exposure in the centre of the nature reserve. The results also demonstrated that foraging NTOs living in the nature reserve were exposed to maize pollen from surrounding fields. Considering the cultivation of Bt-maize MON810, the assumption of the Environmental Risk Assessment (ERA) that there will be no relevant exposure beyond the Bt-maize fields, cannot be confirmed. Considering the results of this and related studies and with respect to the precautionary principle, one can state that buffer zones between Bt-maize fields and protected areas are an effective measure to minimise the exposure of Bt-maize pollen to NTOs and, thus, to prevent from adverse effects. Recommendations and perspectives Because of still insufficient ecotoxicological data for the risk assessment of Bt-maize MON810 considering butterflies and other protected NTOs, protection standards assuring the precautionary principle have to be implemented to avoid Bt-maize pollen exposure to NTOs. This applies for the case Ruhlsdorfer Bruch and for nature reserve areas in general. In order to exclude risks to protected NTOs occurring in nature reserves, sufficient buffer zones for Bt-maize cultivation should be considered. The statistical analysis revealed that distances of more than 500?m are necessary to decisively reduce exposure to foraging insects. In fact, distances of more than 1,000?m are necessary to prevent maize pollen deposition from values above 100,000 pollen/m² with a certainty of 90?%. An adequate risk assessment can only be attained if based on field measurements accounting for the high variation of pollen deposition due to local environmental site conditions and field management. The monitoring should be based on standardised methods. It should include locations with the highest expected deposition rates, the boundaries of the protected areas and sites of interest within those boundaries, e.?g., specific habitats of sensitive species.  相似文献   
99.
Background In recent years, sediments have become a central topic of scientific and public discussion as an important factor for determining water quality. While the quality of surface waters in Germany has significantly improved during the past years, highly contaminated sediments still create a considerable threat to the quality of several European catchment areas. Main features Here, we summarize different concepts and methods for the assessment of sediment quality and report on some novel integrative test methods for assessing sediment toxicity including contaminant re-mobilization during simulated re-suspension events. Results and discussion Currently, different approaches for assessment of sediment pollution exist. While instrumental chemical analyses are not suitable to accurately describe sediment toxicity, combinations of biological and chemical test procedures and integrated approaches, for example weight-of-evidence studies and effect-directed analysis (EDA), have the potential to identify key contaminants. Inter-disciplinary studies combining hydrodynamic and toxicological aspects coupled to real exposure of aquatic organisms to contaminants are currently being developed. Conclusions Monitoring and assessment of sediment quality are of increasing importance, not only for national legislation but also for the implementation of the European Water Framework Directive (WFD). Integrated approaches for the determination of sediment stability play a key role in the appropriate sediment-monitoring strategies.  相似文献   
100.
The transformation of the former blast-furnace site “Hermannhütte” in Dortmund-Hoerde into commercial, residential and service parks, called PHOENIX East and PHOENIX West involves some unusual challenges concerning the water management. The retention of sediments and nutrients plays an important role. To achieve the objectives, various management measures are being used. The installation of an artificial lake in PHOENIX East, which is groundwater- and rainfed, has different requirements than the conventional purification and retention of surface water in PHOENIX West. Both conventional methods such as storm water sedimentation tank and -reservoirs as well as soil filtration, phosphates elimination, Biodyozon®-plant and biomass management ensure good water quality.  相似文献   
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