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91.
Mohammad A. Hoque Aftab A. Khan M. Shamsudduha Muhammad S. Hossain Tariqul Islam Shahid H. Chowdhury 《Environmental Geology》2009,56(8):1687-1695
This study investigated the relationship between near-surface lithology and the spatial variability of As concentrations using
sediment grain-size analysis and electromagnetic induction survey in the southeast Bangladesh. It has been observed that the
aquifers overlain by finer sediments have higher concentrations of As in groundwater, whereas As concentrations are remarkably
low in aquifers having permeable sandy materials or thinner silt/clay layer at the surface. The near-surface lithology acts
as a controlling factor for spatial distributions of groundwater As within the very shallow depths (<15 m). Shallow alluvial
aquifers can provide low-As drinking water in many areas of the country when tube wells are properly installed after investigation
of the overlying near-surface sediment attributes and hydraulic properties. 相似文献
92.
Accumulation of heavy metals in soil and uptake by plant species with phytoremediation potential 总被引:14,自引:1,他引:13
J. Nouri N. Khorasani B. Lorestani M. Karami A. H. Hassani N. Yousefi 《Environmental Earth Sciences》2009,59(2):315-323
Contamination of heavy metals represents one of the most pressing threats to water and soil resources, as well as human health.
Phytoremediation can be potentially used to remediate metal contaminated sites. In this study, concentrations of copper, zinc,
iron, and magnesium accumulated by native plant species were determined in field conditions of Hame Kasi iron and copper mine
in the central part of Iran in Hamadan province. The results showed that metal accumulation by plants differed among species
and tissue bodies. Species grown in substrata with elevated metals contained significantly higher metals in plants. Metals
accumulated by plants were mostly distributed in root tissues, suggesting that an exclusion strategy for metal tolerance exists
widely amongst them. The mentioned species could accumulate relatively higher metal concentrations far above the toxic concentration
in the plant shoots. With high translocation factor, metal concentration ratio of plant shoots to roots indicates internal
detoxification metal tolerance mechanism; thus, they have potential for phytoextraction. The factors affecting metal accumulation
by plant species including metal concentrations, pH, electrical conductivity, and nutrient status in substrata were measured.
Mostly, concentrations of zinc and copper in both aboveground and underground tissues of the plants were significantly, positively
related to their total in substrata, while iron, zinc, and copper were negatively correlated to soil phosphorus. 相似文献
93.
A. Shokati Poursani A. Nilchi A. Hassani S. Tabibian L. Asad Amraji 《International Journal of Environmental Science and Technology》2017,14(7):1459-1468
In this work, synthesis of chitosan beads impregnated with nano-γ-Al2O3 (AlCB) was carried out. The characteristics of the synthesized adsorbent were obtained by using Brunauer Emmett and Teller technique and Scanning Electron Microscopy method. The use of AlCB in continuous removal of chromium, lead, nickel and cadmium ions from liquid solution was studied using fixed-bed column system. Bed depths and flow rate effects on breakthrough and uptake capacity of the adsorbent in column were also examined. Dynamic parameters of the adsorption were calculated by using bed depth service time (BDST) and Thomas models. In both models, the data were analyzed by error analyzing and combining the values of determined coefficient (R 2) from regression analysis. The adsorption capacities of AlCB in breakthrough were 158.33, 183.33, 63.33 and 31.67 mg/g for chromium, lead, nickel and cadmium, respectively. In addition, BDST model was found to be an acceptable kinetic model to describe the experimental data. 相似文献
94.
Simplified design methods for obtaining the maximum strain in pipelines crossing active faults proposed by Newmark, Kennedy and Wang have not considered the section deformation of the pipe. In this study, a new simplified method is developed for obtaining the maximum strain in steel pipes crossing faults considering non‐linearity of material and geometry of pipe section. It is assumed that the pipe will bend near the fault and the geometry of pipe in the longitudinal direction will change according to a bent deformation. On the other hand, the relation between maximum strain and bent angle has been obtained using a beam–shell hybrid FEM for different pipe‐fault conditions. The developed method can be used for calculating the maximum strains for fault‐crossing steel pipes with different angles of crossing both in tension and compression, by considering the deformation of the pipe cross‐section. Copyright © 2001 John Wiley Sons, Ltd. 相似文献
95.
The evolution of landforms and soils from the Jaldi and Maiskhali anticlines and adjoining areas in a part of the coastal region of the north–south trending fold belt of Bangladesh during the Late Quaternary Period has been investigated. Based on the degree of soil development and luminescence dating, eight soil geomorphic units have been deciphered and grouped into four members (I–IV) of a morphostratigraphic sequence for the study area. Various soil geomorphic units included in different member/sub-members are: Member I—river floodplains and active tidal flats (< 500 years); Member II—distal Piedmont Plains and old tidal flats (0.5–2 ka); Member III—proximal Piedmont Plains (6–10 ka); and Member IV—Mainland Higher and Lower Hillocks and Island Hillocks (> 15 ka). Member IV is further subdivided into Sub-member IVa—Island Hillocks (15–18 ka); Sub-member IVb—Mainland Lower Hillocks (23–25 ka); and Sub-member IVc—Mainland Higher Hillocks (30–35 ka).The youngest and poorly developed soils of Member I show features related to hydromorphism. Moderately developed soils of Members II and III show a fersiallitisation stage of pedogenesis. Member IV includes ‘strongly developed soils’ with a ferrugination stage of pedogenesis. These soils also exhibit degradation and poor birefringence of argillans and ferriargillans, indicating a significant change in conditions of pedogenesis, probably related to a paleoclimatic change from a subhumid to semiarid phase (40 ka to about 16 ka) to a hot humid to subhumid phase (16 ka–present). Parent material composition and physiography also have affected the pedogenesis in the area.Based on ages and heights above the mean sea level for the five terraces recognized in the study area, the overall base-level rise rates calculated are about 3.6 mm/year (18 ka–present) for the Maiskhali Island and 2.86 mm/year (35 ka–present) for the mainland (Jaldi anticline). These base level changes represent combined effects of eustatic sea level and tectonic uplift due to folding. 相似文献
96.
97.
This study aims at evaluating the uncertainty in the prediction of soil moisture (1D, vertical column) from an offline land surface model (LSM) forced by hydro-meteorological and radiation data. We focus on two types of uncertainty: an input error due to satellite rainfall retrieval uncertainty, and, LSM soil-parametric error. The study is facilitated by in situ and remotely sensed data-driven (precipitation, radiation, soil moisture) simulation experiments comprising a LSM and stochastic models for error characterization. The parametric uncertainty is represented by the generalized likelihood uncertainty estimation (GLUE) technique, which models the parameter non-uniqueness against direct observations. Half-hourly infra-red (IR) sensor retrievals were used as satellite rainfall estimates. The IR rain retrieval uncertainty is characterized on the basis of a satellite rainfall error model (SREM). The combined uncertainty (i.e., SREM + GLUE) is compared with the partial assessment of uncertainty. It is found that precipitation (IR) error alone may explain moderate to low proportion of the soil moisture simulation uncertainty, depending on the level of model accuracy—50–60% for high model accuracy, and 20–30% for low model accuracy. Comparisons on the basis of two different sites also yielded an increase (50–100%) in soil moisture prediction uncertainty for the more vegetated site. This study exemplified the need for detailed investigations of the rainfall retrieval-modeling parameter error interaction within a comprehensive space-time stochastic framework for achieving optimal integration of satellite rain retrievals in land data assimilation systems. 相似文献
98.
The systematic decline of in situ networks for hydrologic measurements has been recognized as a crucial limitation to advancing
hydrologic monitoring in medium to large basins, especially those that are already sparsely instrumented. As a collective
response, sections of the hydrologic community have recently forged partnerships for the development of space-borne missions
for cost-effective, yet global, hydrologic measurements by building upon the technological advancements since the last two
decades. In this article, we review the state-of-the-art on flood monitoring in medium and large ungauged basins where satellite
remote sensing can facilitate development of a cost-effective mechanism. We present our review in the context of the current
hydro-political situation of flood monitoring in flood-prone developing nations situated in international river basins (IRBs).
Given the large number of such basins and the difficulty in acquisition of multi-faceted geophysical data, we argue that the
conventional data-intensive implementation of physically based hydrologic models that are complex and distributed is time-consuming
for global assessment of the utility of proposed global satellite hydrologic missions. A more parsimonious approach is justified
at the tolerable expense of accuracy before such missions begin operation. Such a parsimonious approach can subsequently motivate
the identified international basins to invest greater effort in conventional and detailed hydrologic studies to design a prototype
flood forecasting system in an effort to overcome the hydro-political hurdles to flood monitoring. Through a modeling exercise involving an open-book watershed concept, we demonstrate the value of a parsimonious approach
in understanding the utility of NASA-derived satellite rainfall products. It is critical now that real-world operational flood
forecasting agencies in the under-developed world come forward to collaborate with the research community in order to leverage
satellite rainfall data for greater societal benefit for inhabitants in IRBs. 相似文献
99.
Ismail Hossain Toshiaki Tsunogae Hariharan M. Rajesh Bin Chen Yoji Arakawa 《Comptes Rendus Geoscience》2007,339(16):979-986
We present new U–Pb SHRIMP zircon geochronological data for basement rocks in Bangladesh, and discuss the relationship with the formation of the Columbia supercontinent. Euhedral zircons from a diorite sample yield a concordia age of 1730 ± 11 Ma, which is interpreted as the crystallization age. The Palaeoproterozoic age of the examined basement rock and the common occurrences of similar 1.7-Ga geologic units in the Central Indian Tectonic Zone and Meghalaya-Shillong Plateau in Indian Shield suggest their apparent continuation. This, together with the occurrence of similar 1.7-Ga geologic units in the Albany-Fraser belt in Australia and East Antarctica, are used to suggest that the basement rocks in Bangladesh formed towards the final stages of the assembly of the Columbia supercontinent. 相似文献
100.
S. Z. Abbas M. Rafatullah K. Hossain N. Ismail H. A. Tajarudin H. P. S. Abdul Khalil 《International Journal of Environmental Science and Technology》2018,15(1):243-262
Since the last few decades, cadmium anthropocentric sources have been increased drastically. Various chemical and physical approaches for cadmium remediation have been proposed, but these techniques are quite expensive, not healthy for the environment and not efficient at the low concentration of cadmium. Thus, in the last few years, the cadmium removal by biological approaches has received a great interest. Many bacteria can resist against high concentration of cadmium through different mechanisms. The cadmium-resistant bacteria can be grouped into three levels. The main group consists of bacteria which efflux the cadmium from the cells. The bacteria of the other two groups are capable of detoxifying or binding cadmium. The cadA and cadB gene systems are involved in efflux mechanism, and these encode different efflux pump proteins, while the functional groups such as amine, carboxyl, phosphate and hydroxyl facilitate cadmium binding to bacterial surface such as chemisorption. Many enzymes are involved in the detoxifying the cadmium and make the membrane impermeable against cadmium. This paper also reviews the industrial application of cadmium-resistant bacteria and the future perspectives of genetic engineering, bioelectrochemical system, microbial aggregates and biosorption of cadmium by algae. 相似文献