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1.
An analysis is presented of 46 ice break up and 15 ice free season phenology data series obtained largely through volunteer monitoring efforts in Southern Ontario. Observations spanned the years 1853–2001. Available data included dates of ice formation and ice break up as well as the number of ice free days in a year. A high degree of temporal coherence in ice phenology between lakes was observed (137/365 pairwise correlations significant at P<0.05). Significant monotonic trends towards earlier break up dates and longer ice free seasons were observed across the region both in the entire series and in the last thirty years of data. Trends in longer series may be associated with the end of the Little Ice Age. The significantly longer ice free seasons and earlier ice break up dates observed in the study area have important implications for lakes in other parts of Canada where climate change effects are predicted to be more extreme than in South-Central Ontario.  相似文献   

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The option of reusing greywater is proving to be increasingly attractive to address the water shortage issue in many arid and semiarid countries. Greywater represents a constant resource, since an approximately constant amount of greywater is generated from kitchen, laundries, bathroom in every household daily, independent of the weather. However, the use of greywater for irrigation in particular for household gardening may pose major hazards that have not been studied thoroughly. In this study, a 1-year monitoring was conducted in four selected households in Perth, Western Australia. The aim of the monitoring works is to investigate the variability in the greywater flow and quality, and to understand its impact in the surrounding environments. Case studies were selected based on different family structure including number, ages of the occupants, and greywater system they used. Samples of greywater effluent (showers, laundries, bathtub, and sinks), leachate, soil, and plants at each case study were collected between October 2008 and December 2009 which covered the high (spring/summer) and low (autumn/winter) production of greywater. Physical and chemical tests were based on the literature and expected components of laundry and bathroom greywater particularly on greywater components likely to have detrimental impacts on soils, plants, and other water bodies. Monitoring results showed the greywater quality values for BOD, TSS, and pH which sometimes fell outside the range as stipulated in the guidelines. The soil analyses results showed that salinity, SAR, and the organic content of the soil increased as a function of time and affected the plant growth. Nutrient leaching or losses from soil irrigated with greywater shows the movement of nutrients and the sole impact from greywater in uncontrolled plots in case studies is difficult to predicted due to the influence of land dynamics and activities. Investigative and research monitoring was used to understand greywater irrigation in households. Greywater quality is very site specific and difficult to predetermine or control except for the use of some recommended household products when using greywater. Investigative and research monitoring was indicated that greywater quality is very site specific and difficult to predetermine or control except for the use of some recommended household products when using greywater.  相似文献   

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This paper provides a coherent microeconomic framework for defining and measuring the social costs of environmental regulations. A fundamental identity between two alternative means of measuring social costs is established and used to illustrate how erroneous methodologies have crept into the impact assessment literature. Several interesting cases of “ripple effects” including those related to the siting of hazardous waste disposal facilities are considered using this identity.  相似文献   

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Composition of the vegetation and the properties of its environment are related, as was shown by research. In these, mostly statistical-correlative studies, both the vegetation and some growth factors, such as plant nutrients and moisture supply were analyzed and studied on interdependence. At present the environmental conditions can be estimated in the field from the floristic composition with regard to differences both in the combination of plant species and in their relative biomass production. With a vegetation survey the spatial pattern of the different environmental conditions can be indicated. For instance, the places where moisture supply gradients occur can be detected, also a better understanding is obtained of the environmental equalization and the decreasing number of plant species and spatial diversity. Conclusions can be drawn about changes in the vegetation to be expected, from the combined occurrence of, a terrestrial vegetation indicating an eutrofied environment and a water vegetation indicating a relatively oligotrophic environment. By comparing vegetation recordings of the past and present, environmental changes that have occurred in the same place can be indicated. By vegetations situated in different places in relation with soil profile properties the consequences of environmental changes can be predicted. For instance, lowering of the ground water table and intensifying the agricultural use. On the other hand, measures can be suggested to increase the biological value of land and water, for instance, indication of seepage areas and floristically rich areas in the field.  相似文献   

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The impact of dredging on a biological community is assessed through the use of log-linear modelling. The experiment is designed as a nested design and the data is collected at several stations within each of natural and dredged areas. The log-linear modelling analysis indicates the dredging has an impact on the abundance of dominant species.  相似文献   

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The Brindisi area is characterized by the presence of industries with high environmental impact, located along its eastern border. Epidemiological studies have revealed several critical situations: two short-term (2003-2005) epidemiological studies have shown that PM(10) and NO(2) are adversely associated with daily hospital admissions: one of the two pointed to the associations with wind blowing from the southern, eastern and western sectors. This study aims to expand the time span of available air quality data in order to provide a more complete and extensive epidemiological study. Multi-year series (from 1992 to 2007) of SO(2), NO(2), and TSP concentration data are presented and analyzed. Data show a significant downward trend of SO(2) from 1992 to 2007, while for the TSP series, the downward trend is limited to the period 1992-1994. Marked seasonal trends are evident for all three pollutants, especially for NO(2) and TSP. The NO(2) series shows higher levels in winter. Inversely, the TSP series shows its maximum values during the summer months, associated with a moderate correlation with temperature and a poor correlation with other pollutants. Analysis of the series for wind sectors revealed the influence of the industrial site and of the harbor. The concentration series exhibit high concentration values and stronger correlations between them and with meteorology for wind blowing from the eastern sectors. Overall analysis supports the hypothesis of a different origin for TSP during the year and for different wind regimes and therefore possible size and chemical differences in TSP, which should be further investigated due to their health implications.  相似文献   

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In this paper, variability in precipitation pattern of Pakistan due to environmental and climatic changes has been studied. Maps have been generated to depict global precipitation variation. Precipitation data of 25 stations of Pakistan have been used. These data were taken from Meteorological Department, Islamabad, Pakistan. The results of two global climate models, namely Australia’s Commonwealth Scientific and Industrial Research’s third generation general circulation model and National Center for Atmospheric Research’s first generation precipitation circulation model for A2 scenario have been applied to investigate the changes. It is observed that precipitation pattern will change significantly in the future. The occurrence of precipitation in all seasons for Pakistan is expected to increase with almost uniform distribution across a season. Average annual precipitation of the country will undergo an increase in the range of +57 to +71 % as compared to average of the base period.  相似文献   

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Pre-marketing assessments of chemicals regarding their potential environmental impacts contain numerous sources of error and uncertainties. Practices and methods for the evaluation of environmental risks posed by individual pre-selected agents seem unsuitable for detecting unexpected trends in the environment. This is particularly so in view of the multitude of anthropogenic assaults on the environment and their complex interactions. Therefore, requirements for symptom-oriented biological effect-test systems, bioprobes, capable of reacting sensitively to environmental changes of unknown origin were conceived. Bioprobes designed to detect biological effects should respond to a broad spectrum of anthropogenic chemicals. They are environmental quality measuring devices consisting of cultivated organisms, cells, organelles or biomolecules in combination with recording units. In contrast to traditional biotests for chemical testing, bioprobes are deliberately exposed to selected segments of the environment for certain periods of time. During and after such exposures, changes of defined biological states or process rates—observation elements—are registered.  相似文献   

11.
In the last twenty years, both the increase in academic production and the expansion of professional involvement in Environmental Impact Assessment (EIA) and Social Impact Assessment (SIA) have evidenced growing scientific and business interest in risk and impact analysis. However, this growth has not brought with it parallel progress in addressing the main shortcomings of EIA/SIA, i.e. insufficient integration of environmental and social factors into development project analyses and, in cases where the social aspects are considered, technical-methodological failings in their analysis and assessment. It is clear that these weaknesses carry with them substantial threats to the sustainability (social, environmental and economic) of projects which impact on the environment, and consequently to the local contexts where they are carried out and to the delicate balance of the global ecosystem. This paper argues that, in a sociological context of complexity and dynamism, four conceptual elements should underpin approaches to socio-environmental risk and impact assessment in development projects: a theoretical base in actor–network theory; an ethical grounding in values which are internationally recognized (though not always fulfilled in practice); a (new) epistemological-scientific base; and a methodological foundation in social participation.  相似文献   

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Stochastic transfer of information in a hierarchy of simulators is offered as a conceptual approach for assessing forest responses to changing climate and air quality across 13 southeastern states of the USA. This assessment approach combines geographic information system and Monte Carlo capabilities with several scales of computer modeling for southern pine species and eastern deciduous forests. Outputs, such as forest production, evapotranspiration and carbon pools, may be compared statistically for alternative equilibrium or transient scenarios providing a statistical basis for decision making in regional assessments. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

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One of the important goals of the next several decades is to achieve and maintain ecologically sustainable development of the biosphere. However, the management of ecological systems is rather difficult, largely because of uncertainties in long-term predictions of environmental and ecological behaviour. Thus, one of the objectives for integrated monitoring should be to provide early indications of impending changes so that mitigative actions can be taken.This paper includes a discussion of the factors to be considered in the design of early-warning monitoring systems, and gives some examples. One approach that appears to be particularly promising is that of identifying, quantifying and monitoring the stresses, feedbacks and component lags in the environmental-ecological system being studied.  相似文献   

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The possibility has been investigated of using the PIXE method to yield long and reliable time series for indicating changes in the environment, with moths or butterflies as a sample target. The suitability of this approach was demonstrated by studying standard deviations of measurements of single moths and those of populations of moths. The properties of targeting at different anatomical sites were investigated and the wing gave the most stable results, perhaps because its metabolic development is completed at the imago (newborn butterfly) stage. According to test measurements of different populations it seems possible to use moth or butterfly wing measurements to study environmental changes over the past century or so using moth or butterfly collections.  相似文献   

16.
Historical records from Ontario's Provincial Water Quality Monitoring Network (PWQMN) for rivers and streams were analyzed to assess the feasibility of mapping regional water quality patterns in southeastern Ontario which spans two major geologic zones, the Precambrian Shield and the St. Lawrence Lowlands, thus serving as a paradigm for much of Ontario. Despite biases toward the populated Lowlands and associated pollution problems, general spatial trends are evident via the analysis of intervariable relations, individual parameter maps and multivariate analysis. Using a robust algorithm designed to identify outliers and abstract underlying bivariate relations, a linear regional hardness-alkalinity relation was derived, where most anomalies proved to be mine drainage impacted sites. Regionally, multivariate ordination reveals that central tendencies of common indicators of ionic strength and nutrient richness correlate positively and that site clusters broadly reflect the transition from oligotrophic Shield waters to eutrophic conditions of heavily agricultural Lowland streams. Results suggest that on the Shield more precisely delineated aquatic regions may be realized by applying GIS to integrate river and synoptic lake survey data. Further synthesis with bedrock and surficial geology, physiography, pedology and other temporally invariant spatial attributes should yield regional patterns of background quality from which locally attainable water objectives might be defined. Additional synoptic surveys of sedimentary Lowland streams may be required as most available sites relflect anthropogenic pollution.  相似文献   

17.
Rapid and unplanned urbanization and industrialization are the main reasons of environmental problems. If urban growth is not based on resource sustainability criteria and urban plans are not applied, natural and human resources are damaged dramatically. In this study, land use change and urban expansion in Edremit region of Turkey is determined by means of remote sensing techniques between 1971 and 2002. To improve the accuracy of land use/cover maps, the contribution of SAR images to optic images in defining land cover types was investigated. To determine the situation of land use/cover types in 2002 accurately, Landsat-5 images and Radarsat-1 images were fused, and the land use/cover types were defined from the fused images. Comparisons with the ground truth reveal that land use maps generated using the fuse technique are improved about 6% with an accuracy of 81.20%. To define land use types and urban expansion, screen digitizing and classification methods were used. The results of the study indicate that the urban areas have been increased 1,826 ha across the agricultural fields which are in land use capability classes of I and II, and significant environmental changes such as land degradation and degeneration of ground water quality occurred.  相似文献   

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Check dam sediments document the process of soil erosion for a watershed. The main objectives of this research are as follows: first, to determine whether the sediments trapped in check dams can provide useful information about local erosion and the environment, and second, to obtain the extent to which they can be stratigraphically interpreted and correlated to the land use history of an area controlled by check dams. Particle size and the concentration of 137Cs in sediments are the indicators used to study the effects of environmental changes on soil erosion in the Loess Plateau, China. A total of 216 soil samples were collected from four sediment profile cores at the Yangjuangou watershed check dam constructed in 1955 and fully silted with sediments by 1965. The results indicated that 137Cs dating and sediment particle size can characterize the sediment deposition process. Silt makes up more than 50 % of the sediment; both the clay and silt sediment fractions decrease gradually in the upstream direction. The sediment profiles are characterized by three depositional layers. These layers suggest changes in the land use. The top layer showed tillage disturbance, with moderate sediments and new soil mixed from 0 to 20 cm. A transition stage from wetlands (characterized by vegetation such as bulrush) to cropland is inferred from sediments at depths of 20–85 cm. Below 85 cm, sedimentary layering is obvious and there is no tillage disturbance. At the downstream site, A0, the average rate of sediment deposition from 1958 to 1963 was approximately 6,125.4 t year?1 km?2. Because of their high time resolution, check dam sediments indicate the effects of environmental changes on soil erosion, and they can provide a multiyear record of the soil erosion evolution at the local scale in the middle reaches of the Yellow River.  相似文献   

20.
Extensive mortality of silversides (Atherinidae), Odontesthes bonariensis, was recorded during July 1989 in the Rapel Reservoir. Temporal and spatial changes observed in biomass concentration (chlorophyll-a) through both ground and remote sensing samples (LANDSAT), allowed us to establish a potential environmental impact. Ground measurements established an input of sulfate (SO4) in a eutrophic area. The mean concentration of biomass tended to decrease in this area in comparison with other mesotrophic areas. The local disfunction associated with the observed biomass changes has been used to develop a prediction in species composition and in biomass concentration.
Resumen Durante la primera semana de Julio de 1989, se registró una muerte masiva de pejerreyes, Odontesthes bonariensis en el Embalse Rapel. En los procesos de monitoreo de la calidad de agua en el Embalse Rapel, se utilizó una representacion espacial primaria de las variables de estado elegidas. Las tendencias témporo-espaciales observadas en la concentración de biomasa fitoplanctónica (clorofila-a) permitieron establecer un impacto ambiental potencial por un agente exógeno al sistema. A partir de mediciones de terreno se estableció la presencia de sulfato (SO4) en una zona de características eutróficas. Los efectos observados en esta zona, en comparación al resto del embalse, fueron una disminución en la concentración media de la biomasa. La disfunción local observada, permitió sustentar una prognosis asociada a la composición de especies fitoplanctónicas y la concentración de biomasa local.
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