共查询到20条相似文献,搜索用时 93 毫秒
1.
Ambient levels of carbonyl compounds and their possible sources were studied at three places in the metropolitan area of Costa
Rica, including a residential, an industrial, and a commercial downtown area with high vehicular flow, during the periods
of April–May and September–December 2009. Fifteen carbonyl compounds were identified in the ambient air, of which acetone
was the most abundant carbonyl, followed by formaldehyde and acetaldehyde. Concentrations were highest in rainy season at
all sites and lower in dry season. These decreases in concentration are explained by the influences of both photochemical
reactions and local meteorological conditions. The strong correlation between C1–C2 and C3 indicated a common origin for these
carbonyls. The C1/C2 ratios varied between 0.49 to 1.05, values which can be considered typical of an urban area. 相似文献
2.
Seema Awasthi Mukesh Khare Prashant Gargava 《Environmental Modeling and Assessment》2006,11(3):267-276
Gaussian-based dispersion models are widely used to estimate local pollution levels. The accuracy of such models depends on
stability classification schemes as well as plume rise equations. A general plume dispersion model (GPDM) for a point source
emission, based on Gaussian plume dispersion equation, was developed. The program complex was developed using Java and Visual
basic tools. It has the flexibility of using five kinds of stability classification schemes, i.e., Lapse Rate, Pasquill–Gifford
(PG), Turner, σ–θ and Richardson number. It also has the option of using two types of plume rise formulations – Briggs and
Holland’s. The model, applicable for both rural and urban roughness conditions, uses meteorological and emission data as its
input parameters, and calculates concentrations of pollutant at the center of each cell in a predefined grid area with respect
to the given source location. Its performance was tested by comparing with 4-h average field data of continuous releases of
SO2 from Dadri thermal power plant (Uttar Pradesh, India). Results showed that the Turner scheme used with Holland’s equation
gives the best outcome having a degree of agreement (d) of 0.522. 相似文献
3.
Demirkesen AC Evrendilek F Berberoglu S 《Environmental monitoring and assessment》2008,138(1-3):101-106
The vulnerability of low-lying coastal areas in Turkey to inundation was quantified based on the sea-level rise scenarios
of 1, 2, and 3 m by 2205. Through digital elevation model (DEM) acquired by the shuttle radar topography mission (SRTM), the
extent and distribution of the high to low-risk coastal plains were identified. The spatio-temporal analysis revealed the
inundated coastal areas of 545, 1,286, and 2,125 km2 at average rates of 5, 10, and 15 mm yr−1 for 200 years, respectively. This is equivalent to minimum and maximum land losses by 2205 of 0.1–0.3% of the total area
and of 1.3–5.2% of the coastal areas with elevations of less than 100 m in the country, respectively. This study provides
an initial assessment of vulnerability to sea-level rise to help decision-makers, and other concerned stakeholders to develop
appropriate public policies and land-use planning measures. 相似文献
4.
Oasis land-use change and its environmental impact in Jinta Oasis, arid northwestern China 总被引:3,自引:0,他引:3
Land use change resulted in land degradation is a focus of research on global environmental changes and plays a significant
role in the stability and economic development of oases in arid regions of China. Jinta Oasis, a typical oasis of temperate
arid zone in northwestern China, was investigated to assess land-use change dynamics during 1988–2003 with the aid of satellite
remote sensing and GIS, and to explore the interaction between these changes and oasis environment. Six land-use types were
identified, namely: cropland, forestland, grassland, water, urban or built-up land, and barren land. The results indicate
that cropland, urban/built-up land, and barren land increase greatly by 30.03, 13.35, and 15.52 km2, respectively; but grassland and forestland areas decrease rapidly by 58.06, and 1.76 km2, respectively. These results also show that obvious widespread changes in land-use occur within the whole oasis over the
study period and result in severe problems of environmental degradation (i.e. land desertification, decline of groundwater,
and vegetation degeneracy). 相似文献
5.
Mandal K Kumar A Tripathi N Singh RS Chaulya SK Mishra PK Bandyopadhyay LK;Council of Scientific Industrial Research 《Environmental monitoring and assessment》2012,184(6):3427-3441
Dust from haul and transport roads are the major source of air pollution in opencast coal mining areas. Dust generated during
mining operations pollutes air which causes different health problems. Various available techniques are implemented in the
field to minimize and control dust in mining areas. However, they are not very effective because dust deposited on road surfaces
are not removed by these techniques. For effective control of dust in opencast mining areas, it has to be regularly collected
from road surfaces and may be converted into solid form, and subsequently can be used as a domestic fuel considering its physicochemical
properties. The present paper describes a comparative study of qualitative and quantitative aspects of road dust samples of
four coalfields of India. The pH of the dust was found to be in the range of 5.1–7.7. Moisture, ash, volatile matter, fixed
carbon, water-holding capacity, bulk density, and specific gravity of dust samples were found to be in the range of 0.5–3.0%,
45–76%, 12.6–20.0%, 10.2–45.3%, 21.17–31.71%, 1.15–1.70, and 1.73–2.30 g cm−3, respectively. Observing the overall generation and characteristics of coal dust, it is suggested that coal dust from haul
and transport roads of mining areas can be effectively collected and used as domestic fuel. 相似文献
6.
Decision–support systems in the field of integrated water management could benefit considerably from social science knowledge,
as many environmental changes are human-induced. Unfortunately the adequate incorporation of qualitative social science concepts
in a quantitative modeling framework is not straightforward. The applicability of fuzzy set theory and fuzzy cognitive maps
for the integration of qualitative scenarios in a decision–support system was examined for the urbanization of the coastal
city of Ujung Pandang, Indonesia. The results indicate that both techniques are useful tools for the design of integrated
models based on a combination of concepts from the natural and social sciences.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
7.
Panichayapichet P Nitisoravut S Simachaya W 《Environmental monitoring and assessment》2007,135(1-3):181-193
The aim of this study was to investigate the spatial distribution of heavy metal in soil and evaluate the dissolution of metal
from soil to ponded-surface water, leaching through soil profiles and metal uptake in grass as related to different land-use
practices. The data provided a scientific basis for best-management practices for land use in Khli Ti watershed. The watershed
has a Pb-contamination problem from the previous operation of a Pb-ore concentrator and abandoned Zn–Pb mine. Sampling sites
were selected from a land-use map, with land-use types falling into the following four categories: forest, agricultural land,
residential area and road. Soil, ponded-surface water, grass samples and soil profiles were collected. The study related soil
characteristics from different land-use practices and locations with observed metal concentrations in ponded-surface water
and soil. High enrichment factors of Pb and As in soil were found. Partitioning coefficient, Kd values were in the order: Cr > Pb > Ni > Cu > Cd > Zn. Soil disturbance from land-use activities including tillage and traffic
increased leaching of trace metal from soils. Pb in soil was significantly taken up by grass even though the Transfer Factor,
TF values were rather low. Agricultural activities in the watershed must be limited. Moreover, land encroachments in the upper
and middle part of the watershed which have high potential of Pb must be strictly controlled in order to reduce the Pb contamination
from non-point sources. 相似文献
8.
Michael G. Hutchins Amelie Deflandre-Vlandas Paulette E. Posen Helen N. Davies Colin Neal 《Environmental Modeling and Assessment》2010,15(2):93-109
A combined semi-distributed hydrological model (CASCADE/QUESTOR) is used to evaluate the steady-state that may be achieved
after changes in land-use or management and to explore what additional factors need to be considered in representing catchment
processes. Two rural headwater catchments of the River Derwent (North Yorkshire, UK) were studied where significant change
in land-use occurred in the 1990s and the early 2000s. Much larger increases in mean nitrate concentration (55%) were observed
in the catchment with significant groundwater influence (Pickering Beck) compared with the surface water-dominated catchment
(13% increase). The increases in Pickering Beck were considerably greater than could be explained by the model in terms of
land-use change. Consequently, the study serves to focus attention on the long-term increases in nitrate concentration reported
in major UK aquifers and the ongoing and chronic impact this trend is likely to be having on surface water concentrations.
For river environments, where groundwater is a source, such trends will mask the impact of measures proposed to reduce the
risk of nitrate leaching from agricultural land. Model estimates of within-channel losses account for 15–40% of nitrate entering
rivers. 相似文献
9.
Habitat loss and fragmentation are often concurrent to land conversion and urbanization. Simple application of GIS-based landscape pattern indicators may be not sufficient to support meaningful biodiversity impact assessment. A review of the literature reveals that habitat definition and habitat fragmentation are frequently inadequately considered in environmental assessment, notwithstanding the increasing number of tools and approaches reported in the landscape ecology literature.This paper presents an approach for assessing impacts on habitats on a local scale, where availability of species data is often limited, developed for an alpine valley in northern Italy. The perspective of the methodology is multiple scale and species-oriented, and provides both qualitative and quantitative definitions of impact significance. A qualitative decision model is used to assess ecological values in order to support land-use decisions at the local level. Building on recent studies in the same region, the methodology integrates various approaches, such as landscape graphs, object-oriented rule-based habitat assessment and expert knowledge.The results provide insights into future habitat loss and fragmentation caused by land-use changes, and aim at supporting decision-making in planning and suggesting possible ecological compensation. 相似文献
10.
Spatial autocorrelation in ecological systems is a critical issue for monitoring (and a general understanding of ecological dynamics) yet there are very few data available, especially for riverine systems. Here, we report here on assemblage-level autocorrelation in the benthic-invertebrate assemblages of riffles in two adjacent, relatively pristine rivers in south-eastern Victoria, Australia (40-km reaches of the Wellington [surveys in summers of 1996 and 1997] and Wonnangatta Rivers [survey in summer of 1996 only], with 16 sites in each river). We found that analyses were similar if the data were resolved to family or to species level. Spatial autocorrelation was assessed by using Mantel-tests for the data partitioned into different sets of spatial separations of survey sites (e.g. 0–6 km, 6–12 km, etc.). We found strong small-scale (≤6 km) autocorrelation in the Wellington River, which is consistent with known dispersal abilities of many aquatic invertebrates. Surprisingly, there were strong negative correlations at longer distance classes for the Wellington River in one of the two summers (20–40 km) and the Wonnangatta River (12–20 km). That two largely unimpacted, adjacent rivers should have such different autocorrelation patterns suggests that impact assessment cannot assume dependence or independence of sites a priori. We discuss the implications of these results for use of “reference” sites to assess impacts at nominally affected sites. 相似文献
11.
Distribution of heavy metals in water, particulate matter and sediments of Gediz River (Eastern Aegean) 总被引:1,自引:0,他引:1
The present paper is the first document of heavy metal levels in surficial sediment, water and particulate matter of the Gediz
River collected from five different sites in August, October 1998, February, June 1999. The present work attempts to establish
the status of distribution and environmental implications of metals in the sediment, water and particulate matter and their
possible sources of derivation. The concentrations of mercury ranged 0.037–0.81, 120–430; lead 0.59–1.5, 190–8,100; copper
0.24–1.6, 30–180; zinc 0.19–2.9, 10–80; manganese 30–170, 20–490; nickel 0.39–9.0, 100–510; iron 1.3–687, 100–6,200 μg/l in
water and particulate matter, respectively. The maximum values in water were generally obtained in summer periods due to industrial
and agricultural activities at Muradiye. The particulate metal concentrations also generally showed increased levels from
the upper Gediz to the mouth of the river. Calculation of metal partition coefficients shows that the relative importance
of the particulate and the water phases varies in response to water hydrochemistry and suspended solid content, but that most
elements achieve a conditional equilibrium in the Gediz River. The metals ranged between Hg: 0.25–0.49, Cr: 59–814, Pb: 38–198,
Cu: 15–148, Zn: 34–196, Mn: 235–1,371, Ni: 35–175, and Fe: 10,629–72,387 mg/kg in sediment. The significant increase of metals
found in Muradiye suggested a pollution effect, related to anthropogenic wastes. Also, relatively high concentrations of Ni
and Mn occurred in sampling site upstream, due to geochemical composition of the sediments. Maximum values of contamination
factor for metals were noticed for sediment of Muradiye. The sampling stations have very high degree of contamination indicating
serious anthropogenic pollution. 相似文献
12.
The Lachlan River system of inland New South Wales, which extends into semi-arid areas, is prone to natural extremes of climate and water quality and has been almost entirely modified since European settlement in Australia. We used this system as a proving ground for the mainly qualitative bioassessment metrics for river macroinvertebrates that are used widely in Australia – the EPT (Ephemeroptera, Plecoptera and Trichoptera) index, the SIGNAL (Stream Invertebrate Grade Number Average Level) biotic index and the AUSRIVAS O/E (Australian River Assessment System Observed over Expected) index – plus a recently developed qualitative index, the observed proportion of potential taxa (OPP). We tested these metrics on their ability to discriminate between sites judged to be less disturbed by human activities (reference sites) and sites selected by a semi-random process and therefore expected to have a higher average level of human disturbance (assessment sites). All metrics except the AUSRIVAS O/E index differed significantly between the two types of sites at higher altitudes, with SIGNAL showing the greatest discrimination. Assessment at these altitudes was more effective if based on composite data from multiple mesohabitats rather than data from single mesohabitats. No metric differentiated the two types of sites in the more arid, lowland, floodplain region of the river system. We suggest that Australia relies too heavily on bioassessment concepts developed to assess water pollution in well-watered regions of the Northern Hemisphere. Effective assessment of human impacts on macroinvertebrates in the rivers of inland Australia requires a better understanding of the roles of flow regimes, including flood and drought sequences, and of microhabitat structure and invasive alien species. Quantitative approaches may also be required. 相似文献
13.
Altun L Baskent EZ Gunlu A Kadiogullari AI 《Environmental monitoring and assessment》2008,137(1-3):149-161
The productivity of forest sites has been indirectly determined with solo wood production objective in forest management.
Forest site productivity should, however, be determined directly in order to implement ecosystem based multipurpose forest
management philosophy. This article tackles the problem in distinguishing and mapping forest sites using both direct method
and indirect method in Genya Mountain located in central of Artvin State Forest Enterprise. About 112 sample plots were designed
and distributed over the area. In each sample plot, soil samples were collected and the classical timber inventory measurements
were taken. According to direct method, Soil Moisture Regime (SMR) method is preferred due to a water deficiency in the study
area. Water holding capacity was used as an essential criterion for the classification of the forest site. Forest site classifications
were assigned regarding the physiographic factors such as landform, aspect, and slope. Five different forest sites classes;
dry, moderate fresh, fresh, humid and hygric were determined. According to direct method, the guiding curve was used to generate
anamorphic site index (SI) equations and three site index classes; good (SI=I–II), medium (SI=III) and low (SI=IV–V) were
determined. Some important differences between the methods were realized. The forest sites determined with site index estimation
method indicate that site index I and II is 505.99 ha, III 1095.79 ha and IV and V 992.95 ha, whereas forest sites determined
with direct method related to dry site of 937.58 ha, moderate fresh site of 931.90 ha, fresh site of 1,797.71 ha, humid site
of 80.48 ha and hygric site of 356.55 ha. The forest site maps of both methods were created using GIS functions. The forest
sites of open and degraded areas should be determined according to direct method. 相似文献
14.
Landscape connectivity, as an important indicator of regional landscape functional pattern measured by cost–distances model,
could both reveal evidence of, and act as an indicator, for desertification. Using Minqin county as a case study, this study
was further to test cost–distance connectivity for indicating desertification, and to analyze temporal changes of connectivity
in the county from 1977 to 1997. The results further indicate the connectivity interpreted as lower cost–distance and higher
risk of desertification. The temporal change analysis of connectivity provides more detail supplement of desertification processes.
Landscape connectivity changes in the county had three distinctive phases, the strongest decline of log cost–distance with
overwhelming decrease area and decrease amount in the period 1977–1984, and its slight decline with the relative balance between
the high decrease amount and high increase amount in the period 1984–1992, then its the slight decline with the relative balance
between the low decrease amount and low increase amount in the period 1992–1997. The frequent temporal and spatial transition
in source class, grassland, alkali–saline land and irrigated cultivated land caused negative effects on the oasis environment. 相似文献
15.
Sezgin Hacısalihoğlu 《Environmental monitoring and assessment》2010,165(1-4):255-262
The main goal of this research was soil-loss determination and comparison of the plot measurement results with simulation model (universal soil loss equation (USLE)) results in different land use and slope classes. The research took place in three different land-use types (Scotch pine forest, pasture land, and agricultural land) and in two different slope classes (15–20%, 35–40%). Within six measurement stations (for each land-use type and slope class-one station), totally 18 measurement plots have been constituted, and soil-loss amount measurements have been investigated during the research period (3 years along). USLE simulation model is used in these measurement plots for calculation the soil-loss amounts. The results pointed out that measured (in plots) and simulated (with USLE) soil-loss amounts differ significantly in each land-use type and slope class. 相似文献
16.
Salve PR Satapathy DR Katpatal YB Wate SR 《Environmental monitoring and assessment》2007,133(1-3):87-98
Stratospheric input and photochemical ozone formation in the troposphere are the two main sources determining the ozone levels
in the surface layer of the atmosphere. Because of the importance of ozone in controlling the atmospheric chemistry and its
decisive role in the heat balance of atmosphere, leading to climate change, the examination of its formation and destruction
are of great interest. This study characterized the distribution of Ground level Ozone (GLO) in Chandrapur district is lying
between 19°25′N to 20°45′N and 78°50′E to 80°10′E. Continuous ozone analyzer was used to quantify GLO at thirteen locations
fixed by Global Positioning System (GPS) during the winter of 2005–2006. The daily GLO at all the locations ranged between
6.4 and 24.8 ppbv with an average and standard deviation of 14.9 ± 6.5 ppbv. The maximum and minimum concentration occurs
during 1300–1600 h and 0300–0500 h may be due to high solar radiation facilitating photochemical production of O3 and downward mixing from the overlying air mass and in situ destruction of ozone by deposition and/or the reaction between
O3 and NO. GIS based spatial distribution of GLO in Chandrapur district is indicates that the central core of the district and
southern sites experienced elevated levels of GLO relative to the northern and western areas. The sites near by Chandrapur
city are particularly affected by elevated GLO. The average variation of GLO with temperature shows a significant correlation
of r = 0.55 indicating a direct relationship between GLO and temperature. Similarly an attempt has been made to compare the GLO
monitored data in Chandrapur district with the reported values for other locations in Indian cities. This generated database
helps regulatory agencies to identify locations where the natural resources and human health could be at risk. 相似文献
17.
Characterizations of volatile organic compounds during high ozone episodes in Beijing,China 总被引:3,自引:0,他引:3
Air samples were collected in Beijing from June through August 2008, and concentrations of volatile organic compounds (VOCs)
in those samples are here discussed. This sampling was performed to increase understanding of the distributions of their compositions,
illustrate the overall characteristics of different classes of VOCs, assess the ages of air masses, and apportion sources
of VOCs using principal compound analysis/absolute principal component scores (PCA/APCS). During the sampling periods, the
relative abundance of the four classes of VOCs as determined by the concentration-based method was different from that determined
by the reactivity approach. Alkanes were found to be most abundant (44.3–50.1%) by the concentration-based method, but aromatic
compounds were most abundant (38.2–44.5%) by the reactivity approach. Aromatics and alkenes contributed most (73–84%) to the
ozone formation potential. Toluene was the most abundant compound (11.8–12.7%) during every sampling period. When the maximum
incremental reactivity approach was used, propene, toluene, m,p-xylene, 1-butene, and 1,2,4-trimethylbenzene were the five
most abundant compounds during two sampling periods. X/B, T/B, and E/B ratios in this study were lower than those found in
other cities, possibly due to the aging of the air mass at this site. Four components were extracted from application of PCA
to the data. It was found that the contribution of vehicle exhaust to total VOCs accounted for 53% of VOCs, while emissions
due to the solvent use contributed 33% of the total VOCs. Industrial sources contributed 3% and biogenic sources contributed
11%. The results showed that vehicle exhausts (i.e., unburned vehicle emissions + vehicle internal engine combustion) were
dominant in VOC emissions during the experimental period. The solvent use made the second most significant contribution to
ambient VOCs. 相似文献
18.
Land use and land cover (LULC) of the Republic of the Maldives: first national map and LULC change analysis using remote-sensing data 总被引:1,自引:0,他引:1
Luca Fallati Alessandra Savini Simone Sterlacchini Paolo Galli 《Environmental monitoring and assessment》2017,189(8):417
The Maldives islands in recent decades have experienced dramatic land-use change. Uninhabited islands were turned into new resort islands; evergreen tropical forests were cut, to be replaced by fields and new built-up areas. All these changes happened without a proper monitoring and urban planning strategy from the Maldivian government due to the lack of national land-use and land-cover (LULC) data. This study aimed to realize the first land-use map of the entire Maldives archipelago and to detect land-use and land-cover change (LULCC) using high-resolution satellite images and socioeconomic data. Due to the peculiar geographic and environmental features of the archipelago, the land-use map was obtained by visual interpretation and manual digitization of land-use patches. The images used, dated 2011, were obtained from Digital Globe’s WorldView 1 and WorldView 2 satellites. Nine land-use classes and 18 subclasses were identified and mapped. During a field survey, ground control points were collected to test the geographic and thematic accuracy of the land-use map. The final product’s overall accuracy was 85%. Once the accuracy of the map had been checked, LULCC maps were created using images from the early 2000s derived from Google Earth historical imagery. Post-classification comparison of the classified maps showed that growth of built-up and agricultural areas resulted in decreases in forest land and shrubland. The LULCC maps also revealed an increase in land reclamation inside lagoons near inhabited islands, resulting in environmental impacts on fragile reef habitat. The LULC map of the Republic of the Maldives produced in this study can be used by government authorities to make sustainable land-use planning decisions and to provide better management of land use and land cover. 相似文献
19.
Different sources of pollution in Karasu Creek were investigated to obtain the water quality and ratio of contamination in
this region. To achieve the main objectives of the present study, water samples were collected from Karasu Creek, starting
from flow pattern at the upstream site of Akkaya Dam to the end of the dam, crossing the place where the Creek drains into.
Dissolved oxygen, electrical conductivity, temperature and maximum/minimum pH were measured systematically for 12 months in
the stations, where the water samples were collected. Chemical analyses of the water samples were carried out by using Cadas
50 S brand UV spectrometer to find out the Pb, Fe, Cu, Zn, Ni, Cr, Cd, S, F and Cn concentrations. These concentration were
determined in μg/lt as 80–850; 180–4,920; 10–6,100; 440–25,530; 130–2,400; 120–280; 20–150; 214,250–1,113,580; 1,560–4,270
and 40–690, respectively. To determine metal levels of the water samples, multivariate analyses (element coefficient correlation,
coefficient correlation dendrogram, hierarchical cluster analysis dendrogram, model summary and ANOVA) were used. The analyses
yielded highly accurate results. There were positive correlations between some elements and their possible sources were the
same. The stations which resembled each other along the creek were divided into three groups. The water quality of the creek
was low and had toxic qualities. Eutrophication developed in Akkaya Dam along the creek. The source of pollution was thought
to be industrial and residential wastes. Absolute (0–100 m), short distance (100–500 m) and medium distance (500–2,000 m)
conservation areas should be determined in pollution areas along Karasu Creek and they should be improved. 相似文献
20.
Melidis P Akratos CS Tsihrintzis VA Trikilidou E 《Environmental monitoring and assessment》2007,127(1-3):15-27
Thirteen field campaigns were undertaken in the period from December 2, 2002 until September 1, 2004 to collect water samples
in order to characterize the quality of rainfall and roof drainage in the city of Xanthi, a typical provincial city in Greece.
In each campaign, water samples were collected from 10 representative sites in the city (in total 130 samples), representing
areas of distinct land use and human activities (i.e., traffic volume, residence density and industrial activity). The water
samples were analyzed according to drinking water criteria for total coliform (not detected), temperature (range: 0.9–20°C),
pH (range: 3.6–11.4), alkalinity (range: 0–21.5 mg CaCO3/L), nitrate (range: 0–2456 μg/L), ammonium (range: 0–2628 μg/L), sulfate (range: 0–0.5 mg/L), calcium (range: 259.1–3064
μeq/L), magnesium (range: 0.8–488.8 μeq/L), potassium (range: 0.0–110.6 μeq/L) and dissolved heavy metals (Fe, range: 0.01–0.18
mg/L; Mn, range: 0.01–0.09 mg/L; Zn, range: 0.01–0.54 mg/L; Cu, Cr and Ni, not detected). Pollutant concentrations were generally
higher in roof drainage than in rainwater, but both were lower than drinking water standards. Dissolved heavy metal concentrations
were generally higher in the areas of intensive human activities, such as roads with high traffic volume and densely populated
residential areas. The satisfactory quality of rainwater, which results from this analysis, makes its use as grey water possible. 相似文献