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991.
Environmental perception during rapid population growth and urbanization: a case study of Dhaka city
Md. Shahidul Islam Md. Masud Parves Rana Raquib Ahmed 《Environment, Development and Sustainability》2014,16(2):443-453
Dhaka city in Bangladesh has been passing through a hasty process of urbanization and population growth since the last few decades. Rapid growth of population, unplanned urbanization and industrialization in the periphery has generated pressure to the changes in land use pattern, which has also caused huge urban expansion. This expansion process is engulfing cultivated land, vegetation, wetlands and water bodies without considering their environmental impacts. This study argues that these changes and their scale of environmental impacts or sufferings are not equally distributed among the dwellers in Dhaka city. It seeks to explore variations of environmental qualities on the basis of people’s perceptions. The study finds that the dwellers in the city perceive their neighborhood environment differently, which may affect environmental qualities of the area and their sustainable management as well. Therefore, it is imperative to consider spatial variations and inequalities of environmental opportunities or sufferings in urban planning of Dhaka city. 相似文献
992.
Mizukawa Mami Nishimura Noriko Uddin Md. Azhar Kato Yoshiei Uchida Yu-ichi 《Journal of Material Cycles and Waste Management》2023,25(4):2407-2416
Journal of Material Cycles and Waste Management - Si, Al, Cu, and Ag particles’ mixture which mainly composes pulverized silicon-based waste solar cells were individually separated by the... 相似文献
993.
Kumar Rajnish Sharma Anju Srivastava Janmejai Kumar Siddiqui Mohammed Haris Uddin Md. Sahab Aleya Lotfi 《Environmental science and pollution research international》2021,28(30):40431-40444
Environmental Science and Pollution Research - The outbreak of novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected the entire world with its infectious spread and... 相似文献
994.
Most agronomic situations involve a sequence of herbicide, fungicide, and insecticide application. On the other hand, use
of pesticidal combinations has become a standard practice in the production of many agricultural crops. One of the most important
processes influencing the behavior of a pesticide in the environment is its degradation in soil. It is known that due to several
pesticide applications in one vegetation season, the pesticide may be present in mixtures with other pesticides or xenobiotics
in soil. This study examines the role which a mixture of chemicals plays in pesticide degradation. The influence of other
pesticides on the rate of pendimethalin (PDM) degradation in soil was measured in controlled conditions. Mixtures of PDM with
mancozeb or mancozeb and thiamethoxam significantly influenced the degradation of pendimethalin under controlled conditions.
The second type of mixtures, with metribuzin or thiamethoxam, did not affect the behavior of pendimethalin in soil. Also,
we determined the influence of water content on the rate of pendimethalin degradation alone in two soils and compared it to
the rate in three pesticide mixtures. We compared two equations to evaluate the predictors of the rate of herbicide dissipation
in soil: the first-order kinetic and the non-linear empirical models. We used the non-linear empirical model assuming that
the degradation rate of a herbicide in soil is proportional to the difference of the observed concentration of herbicide in
soil at time and concentration of herbicide in the last day of measurement. 相似文献
995.
X.?K.?WangEmail author J.?X.?Zheng D.?S.?Tan B.?Zhou S.?K.?Tan 《Environmental Fluid Mechanics》2016,16(3):635-658
This paper presents an experimental study of the interactions of three fully-submerged, coplanar impinging jets issued from long pipes. The jets were neutrally buoyant and were arranged symmetrically about the axis of a central jet, with two side jets set to intersect with the central jet at two inclination angles (30° and 45°) and three Reynolds numbers (4240, 6400 and 8000). Measurements of the flow fields were performed using particle image velocimetry to examine the flow structures in various planes, i.e., the jet axis plane (X–Y), the jet normal plane (X–Z) and the cross-sectional plane (Y–Z). This flow configuration results in pronounced interactions among the three jets, and hence better mixing than that of a canonical single pipe jet as illustrated by augmented centreline velocity decay, spreading rate and turbulence level. The jets at the inclination angle of 45° impinge and mix more rapidly than those at 30°. For each case, the flow is highly 3-dimensional, and jet development displayed several distinct regions (converging, merging and combining) along the streamwise direction. The expansion of flow in the X–Y plane is similar to the shape of a hyperbola with necking formed immediately downstream of the impinging point, whereas that in the X–Z plane assumes the shape of a parabola with an open rim exhibiting a pronounced velocity deficit in the central part of the combining flow. Self-similarity of streamwise mean velocity is explored in the combining region of the flow on the two planes of symmetry (X–Y and X–Z). Flow development in the combining region is dominated by large-scale vortical structures, including von Kárman-like spanwise vortices in the X–Y plane and secondary circulation in the form of two pairs of counter-rotating streamwise vortices in the Y–Z plane. 相似文献
996.
Duarte CM Agustí S Wassmann P Arrieta JM Alcaraz M Coello A Marbà N Hendriks IE Holding J García-Zarandona I Kritzberg E Vaqué D 《Ambio》2012,41(1):44-55
The Arctic marine ecosystem contains multiple elements that present alternative states. The most obvious of which is an Arctic Ocean largely covered by an ice sheet in summer versus one largely devoid of such cover. Ecosystems under pressure typically shift between such alternative states in an abrupt, rather than smooth manner, with the level of forcing required for shifting this status termed threshold or tipping point. Loss of Arctic ice due to anthropogenic climate change is accelerating, with the extent of Arctic sea ice displaying increased variance at present, a leading indicator of the proximity of a possible tipping point. Reduced ice extent is expected, in turn, to trigger a number of additional tipping elements, physical, chemical, and biological, in motion, with potentially large impacts on the Arctic marine ecosystem. 相似文献
997.
Golfinopoulos SK Nikolaou AD Lekkas TD 《Environmental science and pollution research international》2003,10(6):368-372
Application of chlorination for the disinfection of drinking water results in the formation of a wide range of organic compounds, called disinfection by-products (DBPs), which occur due to the reaction of chlorine with natural organic materials. The occurrence of DBPs was studied in samples from four drinking-water treatment plants (WTPs) and from the distribution network of Athens, Greece. Twenty-four compounds, which belong to different categories of DBPs, were monitored, including trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), haloketones (HAKs), chloral hydrate (CH) and chloropicrin (CP). Sampling was performed monthly for a period of two years, from three different points at each WTP and from eight points atthe distribution network. Samples were analyzed by GC-ECD methods, which included pretreatment with liquid-liquid extraction for volatile DBPs and acidic methanol esterification for HAAs. The results of the analyses have shown the presence of disinfection by-products belonging to all categories studied in all water samples collected after prechlorination. The major categories of DBPs detected were THMs and HAAs, while the other volatile DBPs occurred at lower concentrations. The concentrations of DBPs did not in any case exceed the maximum contaminant levels (MCL) set by USEPA and WHO. However, monitoring these compounds needs to be continued, because their levels could increase due to changes in the quality of water entering the water treatment plants. Reduction of the concentrations of DBPs could be achieved by optimization of the chlorination conditions, taking into account the effect of time. Moreover, research on alternative disinfection methods (e.g. ozone, chlorine dioxide, chloramines) and their by-products should be conducted to evaluate their applicability in the case of the drinking water of Greece. 相似文献
998.
Buszewski B Kowalkowski T 《Environmental science and pollution research international》2003,10(6):343-349
In the middle of the last century in the case of many river basins, it became obvious that the targets of the Helsinki-Commission (HELCOM) concerning a 50% reduction of nitrogen and phosphorus inputs to the Baltic Sea had not been reached. Such conclusions could be derived from the observed loads. But the measurements regarding the analysis were not sufficient to determine what the reasons for this report were, what has to be done to fulfil this agreement and to evaluate the time at which the targets can be reached. This contribution presents the current state of Polish surface water quality as well as results of modelling nutrient and heavy metal emissions into the two biggest Polish river basins: Vistula and Odra, which both cover approximately 90% of Poland's territory. 相似文献
999.
Th. H?pner 《Umweltwissenschaften und Schadstoff-Forschung》1991,3(6):354-361
W?hrend eines Studien- und Beratungs-aufenthalts des Autors bei der Saudi-Arabischen Umweltbeh?rde im Juni/Juli 1991 wurde
der Zustand der Saudi-Arabischen Golfküste untersucht. Von der Kuwaitischen Grenze bis zur Insel Abu Ali sind ca. 770 km Küste
lückenlos zwischen Hoch- und Niedrigwasserlinie ver?lt. W?hrend an den energiereicheren Au?enküsten eine biologische Regeneration
erwartet werden kann, ist sie in den energiearmen Buchten nicht ohne technische Ma?nahmen denkbar. Ver?lungen gibt es au?erdem
am Meeresgrund in noch unbekanntem Ausma?. Für die Ma?nahmen wird die Notwendigkeit betont, ein Umweltqualit?tsziel festzulegen,
das in der Entwicklung zu einem Naturreservat bestehen sollte. 相似文献
1000.
Variability of Lotic Macroinvertebrate Assemblages and Stream Habitat Characteristics Across Hierarchical Landscape Classifications 总被引:1,自引:0,他引:1
Streams are naturally hierarchical systems, and their biota are affected by factors effective at regional to local scales. However, there have been only a few attempts to quantify variation in ecological attributes across multiple spatial scales. We examined the variation in several macroinvertebrate metrics and environmental variables at three hierarchical scales (ecoregions, drainage systems, streams) in boreal headwater streams. In nested analyses of variance, significant spatial variability was observed for most of the macroinvertebrate metrics and environmental variables examined. For most metrics, ecoregions explained more variation than did drainage systems. There was, however, much variation attributable to residuals, suggesting high among-stream variation in macroinvertebrate assemblage characteristics. Nonmetric multidimensional scaling (NMDS) and multiresponse permutation procedure (MRPP) showed that assemblage composition differed significantly among both drainage systems and ecoregions. The associated R-statistics were, however, very low, indicating wide variation among sites within the defined landscape classifications. Regional delineations explained most of the variation in stream water chemistry, ecoregions being clearly more influential than drainage systems. For physical habitat characteristics, by contrast, the among-stream component was the major source of variation. Distinct differences attributable to stream size were observed for several metrics, especially total number of taxa and abundance of algae-scraping invertebrates. Although ecoregions clearly account for a considerable amount of variation in macroinvertebrate assemblage characteristics, we suggest that a three-tiered classification system (stratification through ecoregion and habitat type, followed by assemblage prediction within these ecologically meaningful units) will be needed for effective bioassessment of boreal running waters. 相似文献