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781.
A. Veldkamp P.H. Verburg K. Kok G.H.J. de Koning J. Priess A.R. Bergsma 《Environmental Modeling and Assessment》2001,6(2):111-121
This paper introduces some of the issues that are relevant to the spatially explicit modeling of land use systems. A short overview is given of the ways and means in which a number of different land use change models describe the land use system. Specific attention is given to the empirical modeling approach used in the CLUE (Conversion of Land Use and its Effects) modeling framework. This approach is demonstrated for three case studies in China, Ecuador and the Atlantic Zone of Costa Rica. These case-studies illustrate the methodology for multi-scale analysis of land use driving factors and their application in spatially explicit modeling exercises. Model functioning, performance and limitations are discussed. The presented case-studies indicate that empirical modeling results can contribute to a better theoretic imbedding of land use change research in scale sensitive and integrated theories. 相似文献
782.
Schaefer CE do Amaral EF de Mendonça BA Oliveira H Lani JL Costa LM Fernandes Filho EI 《Environmental monitoring and assessment》2008,140(1-3):279-289
The relationships between soils attributes, soil carbon stocks and vegetation carbon stocks are poorly know in Amazonia, even
at regional scale. In this paper, we used the large and reliable soil database from Western Amazonia obtained from the RADAMBRASIL
project and recent estimates of vegetation biomass to investigate some environmental relationships, quantifying C stocks of
intact ecosystem in Western Amazonia. The results allowed separating the western Amazonia into 6 sectors, called pedo-zones:
Roraima, Rio Negro Basin, Tertiary Plateaux of the Amazon, Javari-Juruá-Purus lowland, Acre Basin and Rondonia uplands. The
highest C stock for the whole soil is observed in the Acre and in the Rio Negro sectors. In the former, this is due to the
high nutrient status and high clay activity, whereas in the latter, it is attributed to a downward carbon movement attributed
to widespread podzolization and arenization, forming spodic horizons. The youthful nature of shallow soils of the Javari-Juruá-Purus
lowlands, associated with high Al, results in a high phytomass C/soil C ratio. A similar trend was observed for the shallow
soils from the Roraima and Rondonia highlands. A consistent east–west decline in biomass carbon in the Rio Negro Basin sector
is associated with increasing rainfall and higher sand amounts. It is related to lesser C protection and greater C loss of
sandy soils, subjected to active chemical leaching and widespread podzolization. Also, these soils possess lower cation exchangeable
capacity and lower water retention capacity. Zones where deeply weathered Latosols dominate have a overall pattern of high
C sequestration, and greater than the shallower soils from the upper Amazon, west of Madeira and Negro rivers. This was attributed
to deeper incorporation of carbon in these clayey and highly pedo-bioturbated soils. The results highlight the urgent need
for refining soil data at an appropriate scale for C stocks calculations purposes in Amazonia. There is a risk of misinterpreting
C stocks in Amazonia when such great pedological variability is not taken into account. 相似文献
783.
Gowri VS Ramachandran S Ramesh R Pramiladevi IR Krishnaveni K 《Environmental monitoring and assessment》2008,138(1-3):41-49
Residential, industrial, commercial, institutional and recreational activities discharge degradable and non-degradable wastes
that reach the coastal water through rivers and cause coastal pollution. In the present study, mass transport of pollutants
by Adyar and Cooum Rivers to the coastal water as a result of land-based discharges was estimated during low tide. The lowest
and the highest flow recorded in Adyar varied from 514.59 to 2,585.08×106 litres/day. Similarly, the flow in Cooum River fluctuated between 266.45 and 709.34×106 litres/day. The present study revealed that the Adyar River transported 53.89–454.11 t/d of suspended solids, 0.06–19.64 t/d
of ammonia, 15.95–123.24 t/d of nitrate and 0.4–17.86 t/d of phosphate, 0.004–0.09 kg/d of cadmium, 0.15–1.29 kg/d of lead
and 3.03–17.58 kg/d of zinc to the coastal water owing to its high discharge. Similarly, the Cooum River transported 11.87–120.06 t/d
of suspended solids, 0.08–58.7 t/d of ammonia, 6.11–29.25 t/d of nitrate and 0.66–10.73 t/d of phosphate, 0.003–0.021 kg/d
of cadmium, 0.02–0.44 kg/d of lead and 1.36–3.87 kg/d of zinc. A higher concentration of suspended solids was noticed in post
monsoon and summer months. An increase in the mass transport of ammonia, nitrate, phosphate in summer months (April and May)
and an increase in the mass transport of cadmium, lead and zinc were observed in monsoon months (October–December) in both
the rivers. Thus mass transport of pollutants study reveal that Cooum and Adyar Rivers in Chennai contribute to coastal pollution
by transporting inorganic and trace metals significantly through land drainage. 相似文献
784.
Montes AM González-Farias FA Botello AV 《Environmental monitoring and assessment》2012,184(3):1359-1369
The lagoon system of Navachiste-Macapule is located in northern Mexico, in the state of Sinaloa, with an area of 24,000 ha.
The main economic activity in the area is agriculture, and the lagoon lies next to the irrigation district ID-063 which covers
116,615 ha. The purpose of this study is to evaluate the levels of pollution generated by organochlorine pesticides (OC) in
the surface sediments of the lagoon and in the agricultural drains of the ID-063 that are supposedly transported into the
system as a result of agricultural activities and runoff from adjacent land. For this, between 2006 and 2007, 45 surface sediment
samples were collected (warm dry, rainy and cold dry) from 15 sampling sites, during the three climatic seasons. Of these,
eight were located inside the lagoon in marine conditions (salinity >31 PSU) and seven in the agricultural drains of the ID-063
in freshwater conditions (salinity <5 PSU). The average concentration of the OC in the sediments was 44.75 ng g − 1, among which the group of the alicyclic compounds presented the greatest concentrations. The average value of the total organic
carbon (TOC) in the sediments of the system was 0.90%. The sediments collected inside the lagoon had an average OC concentration
of 18.97 ng g − 1, and the predominant type of sediment was fine to very fine sand. The average OC concentration in the sediments collected
in the agricultural drains was 75.69 ng g − 1, where fine sediments (silt) were predominant. The presence of methoxychlor, endrin and heptachlor suggested that these compounds
were continuously used in the system, even though their use is forbidden in Mexico. 相似文献
785.
de Figueiredo DR Ferreira RV Cerqueira M de Melo TC Pereira MJ Castro BB Correia A 《Environmental monitoring and assessment》2012,184(1):471-485
The information on bacterial community composition (BCC) in Portuguese water bodies is very scarce. Cértima River (central
western Portugal) is known to have high levels of pollution, namely organic. In the present work, the BCC from a set of 16
water samples collected from Cértima River Basin and its main tributaries was characterized using 16S rDNA–denaturing gradient
gel electrophoresis, a culture-independent molecular approach. Molecular data were related to environmental parameters through
multivariate analysis to investigate potential impact of water pollution along the river. Principal component analysis using
environmental data showed a water quality gradient from more pristine waters (at the mountain tributaries) to waters with
increasingly eutrophic potential (such as Fermentelos Lake). This gradient was mainly defined by factors such as organic and
inorganic nutrient sources, electrical conductivity, hydrogen carbonate concentration, and pH. Molecular results showed variations
in BCC along Cértima River Basin but in the main river section, a Bacteroidetes phylotype (Flavobacterium sp.) proved to be dominant throughout the river course. Multivariate analysis suggests that spatial variation of BCC along
the Cértima River Basin depended mainly on parameters such as Chl a, total suspended solid (TSS), total organic carbon, electrical conductivity, and HCO
_boxclose^-_{3}^{-} levels. Bacteroidetes phylotypes were all related to higher electrical conductivity and HCO3-_{3}^{-} levels although some of these were also correlated with high SO42-_{4}^{2-} and others with high soluble reactive phosphorus, nitrate, TN, and Kjeld-N levels. The Gammaproteobacteria occurrence was correlated with high SO42-_{4}^{2-} levels. One of the Betaproteobacteria phylotypes showed to correlate with low redox potential (Eh) and high temperature, pH, TSS, and Chl a levels while another one showed a negative correlation with Chl a values. 相似文献
786.
Large and mesoscale meteo-oceanographic patterns in local responses of biogeochemical concentrations
de Oliveira MM Pereira GC de Oliveira JL Ebecken NF 《Environmental monitoring and assessment》2012,184(11):6935-6956
Investigations surrounding the variability of productivity in upwelling regions are necessary for a better understanding the physical-biological coupling in these regions by monitoring systems of environmental impacts according to the needs of the regional coastal management. Using a spatial and temporal database from National Centers for Environmental Prediction (NCEP) and National Center for Atmospheric (NCAR) Research reanalysis, Quick Scatterometer vector wind, and surface stations from the Southeast coast of Brazil, we investigate the meteorological influences due to the large-scale systems in the variability of the nutrient and larvae concentration, and chlorophyll a, describing statistically relationships between them in upwelling regions. In addition, we used multivariate analysis, such as PCA and clustering to verify spatial and temporal variances and describe more clear the structure and composition of the ecosystem. Correlation matrix analyses were applied for different water masses present in the study area to identify the relations between physical and biogeochemical parameters in a region, where frequently upwelling occur. Statistical approaches and seasonal variability show that the period of November to March is more sensitive to nutrients (1.20?mg/m(3) for chlorophyll a, 2.20?μmol/l for total nitrogen and 5.5?ml/l for DO) and larvae concentrations (120 org/m(3) for most of the larvae, except for cirripedia that presented values around 370 org/m(3)) relating to the influence of large and mesoescale meteorological patterns. The spatial and temporal variables analyzed with multivariate approach show meaningful seasonality variance of the physical and biological samples, characterizing the principal components responsible for this variance in spring and summer (upwelling period), emphasizing the monitoring of species as crustaceans and mussels that are present in the local economy. Then, the spring and summer season are characterized by high productivity due to the occurrence of upwelling in this period. 相似文献
787.
José Carlos de Moura Xavier Irany de Andrade Azevedo Wilson Cabral de Sousa Junior Augusto Nishikawa 《Environmental monitoring and assessment》2013,185(2):1463-1471
Atmospheric pollutant monitoring constitutes a primordial activity in public policies concerning air quality. In São Paulo State, Brazil, the São Paulo State Environment Company (CETESB) maintains an automatic network which continuously monitors CO, SO2, NO x , O3, and particulate matter concentrations in the air. The monitoring process accuracy is a fundamental condition for the actions to be taken by CETESB. As one of the support systems, a preventive maintenance program for the different analyzers used is part of the data quality strategy. Knowledge of the behavior of analyzer failure times could help optimize the program. To achieve this goal, the failure times of an ozone analyzer—considered a repairable system—were modeled by means of the nonhomogeneous Poisson process. The rate of occurrence of failures (ROCOF) was estimated for the intervals 0–70,800 h and 0–88,320 h, in which six and seven failures were observed, respectively. The results showed that the ROCOF estimate is influenced by the choice of the observation period, t 0?=?70,800 h and t 7?=?88,320 h in the cases analyzed. Identification of preventive maintenance actions, mainly when parts replacement occurs in the last interval of observation, is highlighted, justifying the alteration in the behavior of the inter-arrival times. The performance of a follow-up on each analyzer is recommended in order to record the impact of the performed preventive maintenance program on the enhancement of its useful life. 相似文献
788.
C. Kesavachandran B. S. Pangtey V. Bihari M. Fareed M. K. Pathak A. K. Srivastava N. Mathur 《Environmental monitoring and assessment》2013,185(2):1265-1272
The World Health Organization has estimated that air pollution is responsible for 1.4 % of all deaths and 0.8 % of disability-adjusted life years. NOIDA, located at the National Capital Region, India, was declared as one of the critically air-polluted areas by the Central Pollution Control Board of the Government of India. Studies on the relationship of reduction in lung functions of residents living in areas with higher concentrations of particulate matter (PM) in ambient air were inconclusive since the subjects of most of the studies are hospital admission cases. Very few studies, including one from India, have shown the relationship of PM concentration and its effects of lung functions in the same location. Hence, a cross-sectional study was undertaken to study the effect of particulate matter concentration in ambient air on the lung functions of residents living in a critically air-polluted area in India. PM concentrations in ambient air (PM1, PM2.5) were monitored at residential locations and identified locations with higher (NOIDA) and lower concentrations (Gurgaon). Lung function tests (FEV1, PEFR) were conducted using a spirometer in 757 residents. Both air monitoring and lung function tests were conducted on the same day. Significant negative linear relationship exists between higher concentrations of PM1 with reduced FEV1 and increased concentrations of PM2.5 with reduced PEFR and FEV1. The study shows that reductions in lung functions (PEFR and FEV1) can be attributed to higher particulate matter concentrations in ambient air. Decline in airflow obstruction in subjects exposed to high PM concentrations can be attributed to the fibrogenic response and associated airway wall remodeling. The study suggests the intervention of policy makers and stake holders to take necessary steps to reduce the emissions of PM concentrations, especially PM1, PM2.5, which can lead to serious respiratory health concerns in residents. 相似文献
789.
Timothy Andrew Joyner Robert V. Rohli 《Environmental monitoring and assessment》2013,185(4):3467-3476
Knowledge of water quality conditions is essential in assessing the health of riverine ecosystems. The goal of this study is to determine the degree to which water quality variables are related to precipitation and air temperature conditions for a segment of the Pearl River Basin near Bogalusa, LA, USA. The AQUATOX ecological fate simulation model is used to estimate daily total nitrogen, total phosphorus, and dissolved oxygen concentrations over a 2-year period. Daily modeled output for each variable was calibrated against reliably measured data to assess the accuracy. Observed data were plotted against simulated data for controlled and perturbed models for validation, and stepwise multiple regression analysis was used to quantify the relationships between the water quality and meteorological variables. Results suggest that daily dissolved oxygen is significantly negatively correlated to concurrent daily mean air temperature with a total explained variance of 0.679 (p?<?0.01), and monthly dissolved oxygen is significantly negatively correlated to monthly mean air temperature with a total explained variance of 0.567 (p?<?0.01). Total mean monthly phosphorus concentration is significantly positively related to the previous month's precipitation with a total explained variance of 0.302 (p?<?0.01). These relationships suggest that atmospheric conditions have a strong influence on water quality in the Pearl Basin. Therefore, environmental planners should expect that future climatic changes are likely to alter water quality. 相似文献
790.
C. Sudhakar Reddy C. S. Jha V. K. Dadhwal 《Environmental monitoring and assessment》2013,185(5):4399-4415
Deforestation and fragmentation are important concerns in managing and conserving tropical forests and have global significance. In the Indian context, in the last one century, the forests have undergone significant changes due to several policies undertaken by government as well as increased population pressure. The present study has brought out spatiotemporal changes in forest cover and variation in forest type in the state of Odisha (Orissa), India, during the last 75 years period. The mapping for the period of 1924–1935, 1975, 1985, 1995 and 2010 indicates that the forest cover accounts for 81,785.6 km2 (52.5 %), 56,661.1 km2 (36.4 %), 51,642.3 km2 (33.2 %), 49,773 km2 (32 %) and 48,669.4 km2 (31.3 %) of the study area, respectively. The study found the net forest cover decline as 40.5 % of the total forest and mean annual rate of deforestation as 0.69 %?year?1 during 1935 to 2010. There is a decline in annual rate of deforestation during 1995 to 2010 which was estimated as 0.15 %. Forest type-wise quantitative loss of forest cover reveals large scale deforestation of dry deciduous forests. The landscape analysis shows that the number of forest patches (per 1,000) are 2.463 in 1935, 10.390 in 1975, 11.899 in 1985, 12.193 in 1995 and 15.102 in 2010, which indicates high anthropogenic pressure on the forests. The mean patch size (km2) of forest decreased from 33.2 in 1935 to 5.5 in 1975 and reached to 3.2 by 2010. The study demonstrated that monitoring of long term forest changes, quantitative loss of forest types and landscape metrics provides critical inputs for management of forest resources. 相似文献