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511.
Gopal R. Patil 《Environmental Modeling and Assessment》2016,21(5):629-642
Tailpipe emissions in the road transportation system are a major source of air pollution and greenhouse gases. One of the possible approaches is to influence drivers’ routing decisions such that the emissions and fuel consumption is minimized. In order to evaluate such condition, we develop environmental traffic assignment (E-TA) models based on user equilibrium (UE) and system optimal (SO) behavioral principles. Extending the traditional travel time-based UE and SO principles to E-TA is not straightforward because, unlike travel time, the rate of emissions increases with the increase in vehicle speed beyond a certain point. The results of various TA models show a network-wide traffic control strategy in which vehicles are routed according to SO-based E-TA, can reduce system-wide emissions. However, a system in which drivers make routing decisions to minimize their own emissions (E-UE system) results in a paradoxical situation of increased individual as well as system-wide emissions. 相似文献
512.
A choice experiment is used to estimate how Vietnamese households value a flood risk reduction. The empirical analysis is conducted on a sample of households located in the Nghe An Province, one of the provinces which is the most affected by floods in Vietnam. The results reveal that there is a high level of heterogeneity in preferences across households. We compute the willingness to pay (WTP) for a flood risk reduction, and we identify how it relates to different attributes of flood management policies (reduction of economic losses, reduction of human losses, political level in charge of implementing the flood management policy). In particular, the marginal WTP for reducing the flood fatality rate, which can be interpreted as the value of statistical life (VSL), varies from 2 517 million VND (approximately 120,818 USD) to 3 590 million VND (approximately 172,323 USD) depending on the model considered. The VSL represents between 77 and 111 times the annual household average income in our sample, a result in line with previous estimates in similar countries. 相似文献
513.
Edita Baltrėnaitė Arvydas Lietuvninkas Pranas Baltrėnas 《Environmental Modeling and Assessment》2016,21(5):577-590
Changing the concepts of economic development and introducing new amendments can hardly decrease the accumulation in the soil of such pollutants as metals, remaining there for a long time. The predictive models for describing the balance of metals in the soil, which are based on the ‘atmosphere–plant–soil’ system and reflect the complicated physical–chemical nature of the metals’ migration, expressed by coefficients obtained in long-term observations in natural conditions, allow for evaluating long-term concentration of metals in the soil. The model BALANS evaluates self-purification of soil, taking into account the uptake of metals of aerogenic origin by the soil together with amendments, their physical–chemical migration and the type of microrelief determining its intensity as well as the absorbed biomass of plants and the removal of metals with crops. In this model, the half-period of metals’ washing out from the soil, found for the microrelief characteristic of low places, exceeds 200 years for Ni, Cr and Pb and makes 90 and 150 years for Zn and Cu, respectively. 相似文献
514.
Rainwater harvesting, consisting in collecting runoff from precipitation, has been widely developed to stop groundwater declines and even raise water tables. However, this expected environmental effect is not self-evident. We show in a simple setting that the success of this conjunctive use depends on whether the runoff rate is above a threshold value. Moreover, the bigger the storage capacity, the higher the runoff rate must be to obtain an environmentally efficient system. We also extend the model to include other hydrological parameters and ecological damages, which respectively increase and decrease the environmental efficiency of rainwater harvesting. 相似文献
515.
Smaeyl Hassanzadeh Omid Hajrasouliha Ali Rezaei Latifi 《Environmental Modeling and Assessment》2016,21(6):721-730
The Persian Gulf ecosystem is facing a variety of stresses as a result of being located within the richest oil province in the world, which hosts more than 67 % of the world oil reserve. In this paper, the distribution of oil pollution on the surface layer of the Persian Gulf is predicted for the different months after the release, based on the Coupled Hydrodynamical Ecological model for Regional Shelf seas (COHERENS). An Eulerian model for the Persian Gulf is set up using the Cartesian coordinate in the horizontal direction, and the sigma coordinate in the vertical direction. Based on this model, our analysis and simulation results indicate that the winds lead to diffusion of the contaminant concentration in the direction of the Arabian coast from the initial position of the spill. The results of this study can be used to provide appropriate solutions for preventing oil from spreading further in the region. 相似文献
516.
Karakaya and Sultansuyu Dam Lakes, located in the eastern part of Turkey, are important water sources, both for irrigation
and fishery. The main goal of the study was to investigate water qualities of dam lakes using a set of biomarkers in the fish
Cyprinus carpio. For this aim, field sample and laboratory-acclimated fish were compared to identify changes in selected biomarkers. The
activities of ethoxyresorufin-O-deethylase, glutathione S-transferase, glutathione reductase, and carboxylesterase were determined in liver samples. Also, plasma and liver lactate
dehydrogenase, aspartate aminotransferase, and alanine aminotransferase activities were assayed. Brain acetylcholinesterase
and carboxylesterase activities were also determined. The hepatosomatic index and condition factors were calculated. Plasma
vitellogenin assays were evaluated for the presence of xenoestrogen. Physicochemical values of water samples showed the existence
of eutrophication risk, and also, some chemicals in both lakes were determined to be over tolerable limits. The comparisons
of samples from both dam lake and laboratory-acclimated fish showed that the lakes may be at risk of pollution by some xenobiotics,
namely xenoestrogens and acetylcholinesterase-inhibiting agents. 相似文献
517.
The groundwater level represents a critical factor to evaluate hillside landslides. A monitoring system upon the real-time
prediction platform with online analytical functions is important to forecast the groundwater level due to instantaneously
monitored data when the heavy precipitation raises the groundwater level under the hillslope and causes instability. This
study is to design the backend of an environmental monitoring system with efficient algorithms for machine learning and knowledge
bank for the groundwater level fluctuation prediction. A Web-based platform upon the model-view controller-based architecture
is established with technology of Web services and engineering data warehouse to support online analytical process and feedback
risk assessment parameters for real-time prediction. The proposed system incorporates models of hydrological computation,
machine learning, Web services, and online prediction to satisfy varieties of risk assessment requirements and approaches
of hazard prevention. The rainfall data monitored from the potential landslide area at Lu-Shan, Nantou and Li-Shan, Taichung,
in Taiwan, are applied to examine the system design. 相似文献
518.
Agunbiade FO Olu-Owolabi BI Adebowale KO 《Environmental monitoring and assessment》2012,184(1):89-102
The accumulation patterns of ten metals in tissues of plant, Eichornia crassipes, and fishes, Hydrocynus forskahlii and Oreochromis mossambicus, were modeled with simple fuzzy classification (SFC) to assess toxic effects of anthropogenic activities on the coastal biota.
The plant sample was separated into root, stem, and leaves and the fishes into bones, internal tissues, and muscles. They
were analyzed for As, Cd, Cr, Cu, Ni, Pb, V, Fe, Mn, and Zn after wet oxidation of their dried samples. The results were converted
into membership functions of five accumulation classes and aggregated with SFC. The classification results showed that there
was no metal accumulation in the plant parts while the fishes were classified into low accumulation category. The internal
tissues of the fishes had higher metal accumulation than the other parts. Generally, Fe and Mn had highest concentrations
in the biota but are natural to the area and may not constitute significant risk. Cr had the highest transfer and accumulation
from the coastal water into the aquatic lives and may be indicative of risk prone system being a toxic metal. Metal contaminations
in the zone had not significantly accumulated in the biota making them less prone to risk associated with metal accumulation. 相似文献
519.
The total petroleum hydrocarbons (TPH) pollution in regional agricultural soils was investigated. Seventy soil samples collected
from surface layers (0–20 cm) and horizons of five selected pedons in the vicinity of a petrochemical complex in Guangzhou,
China were analyzed, and the vertical variation and spatial variability of TPH were evaluated. The TPH concentration in top
soils around the petrochemical complex ranged from 1,179.3 to 6,354.9 mg kg − 1, with the average of 2,676.6 mg kg − 1. Furthermore, significant differences between land-use types showed that the TPH concentration in top soils was strongly
influenced by accidental spills. Both the TPH trends in pedons and the identified hot-spot areas also showed that the accidental
explosions or burning accidents were mainly responsible for the pollution. The results reported here suggest that the regular
monitoring and inspection shall be conducted for safety and to avoid or minimize the accidents, and the effective measures
should be taken to remediate the contaminated areas and to assure that the important industrialization of Guangzhou area would
not mean human health risks near the petrochemical complex. 相似文献
520.
The chemical forms and ecological risk of As were characterized in the sediment of the Daliao River System (DRS), which has
been affected by long-term intensive industrial, urban, and agricultural activities. Twenty-seven samples of surface sediment
were collected and analyzed for total As content and that of its chemical forms. The results indicated that the average total
As content in the sediment was 9.83 mg kg − 1 but that the levels ranged from 1.57 to 83.09 mg kg − 1. At the sites near cities, mining sites, and the estuary of the DRS, it is likely that adverse effects on aquatic organisms
occur, due to As levels in the sediment that are often higher than the threshold effect level and occasionally higher than
the probable effect level. A selectively sequential extraction indicated that the majority of As in the sediment was bound
to Fe oxides (62.1%), with moderate proportions of residual As (19.8%), specifically adsorbed As (17.9%), and a low proportion
of non-specifically adsorbed As (1.1%). In addition, the content of Fe in the sediment was positively and significantly correlated
with the contents of amorphous and crystalline Fe oxide-bound As, confirming the crucial role of Fe oxides in immobilizing
high amounts of As in superficial environments. The average molar ratio of As to Fe was 1.18 × 10 − 4 in the surface sediment of the DRS, similar to that of natural Fe oxides, but much lower than that of synthesized Schwertmannite.
Therefore, the release of As under reduced and low pH conditions can cause serious problems for water resources and for living
organisms. 相似文献