Assessment of nutrient and heavy metal content and speciation in sewage sludge from different locations in Iran     

Feizi  Morteza  Jalali  Mohsen  Renella  Gianacrlo 《Natural Hazards》2019,95(3):657-675

More than 80% of sewage sludge (SS) produced in Iran is landfilled with high environmental impact. The chemical properties of SS produced from wastewater plants of cites of Arak, Isfahan, Kermanshah, Rasht, Saveh, Shiraz, Sanandaj, Tehran, Takestan, and Toyserkan were studied to assess the potential beneficial effects of their application to agricultural soil as sustainable SS management. The pH and EC values, total content and water-soluble concentration of nutrients and heavy metals, their water-extractable pools were determined, and their speciation was done through the NICA–Donnan model using the Visual MINTEQ software. Relatively high contents of N, P, and physiologically active cations indicated potential beneficial effects of SS for land application in the agro-ecosystems, whereas the heavy metal content depended on the SS production site, with higher levels found in the SS of the Arak and Saveh wastewater treatment plants. The pH value was the main factor controlling the metal speciation, with Cu and Pb having the highest affinity for the organic matter, and Zn and Mn being mainly present as free ions or inorganic species. Results showed that SS from different locations in Iran differed in their main chemical properties and elemental composition and that speciation analysis could be used to predict potential beneficial and harmful effects of SS, particularly upon the modeling of metal–organic complexes by the NICA–Donnan approach. Globally, our results confirmed that while the SS produced in Iran has potential suitable chemical properties for use in agriculture, their heavy metals load should not be ignored.

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A two-dimensional horizontal wave propagation and mud mass transport model     

Ali Oveisy  Kevin Hall  Mohsen Soltanpour  Tomoya Shibayama 《Continental Shelf Research》2009

The present study offers a two-dimensional horizontal wave propagation and morphodynamic model for muddy coasts. The model can be applied on a general three-dimensional bathymetry of a soft muddy coast to calculate wave damping, fluid mud mass transport and resulting bathymetry change under wave actions. The wave propagation model is based on time-dependent mild slope equations including the wave energy dissipation due to the wave-mud interaction of bottom mud layers as well as the combined effects of the wave refraction, diffraction and breaking. The constitutive equations of the visco-elastic–plastic model are adopted for the rheological behavior of fluid mud. The mass transport velocity within the fluid mud layer is calculated combining the Stokes’ drift, the mean Eulerian velocity and the gravity-driven mud flow. The results of the numerical model are compared against a series of conducted wave basin experiments, wave flume experiments and field observations. Comparisons between the computed results with both the field and laboratory data reveal the capability of the proposed model to predict the wave transformation and mud mass transport.  相似文献   

Considering potential seismic sources in earthquake hazard assessment for Northern Iran     

Gholamreza Abdollahzadeh  Mohammad Sazjini  Mohsen Shahaky  Fatemeh Zahedi Tajrishi  Leila Khanmohammadi 《Journal of Seismology》2014,18(3):357-369

Located on the Alpine-Himalayan earthquake belt, Iran is one of the seismically active regions of the world. Northern Iran, south of Caspian Basin, a hazardous subduction zone, is a densely populated and developing area of the country. Historical and instrumental documented seismicity indicates the occurrence of severe earthquakes leading to many deaths and large losses in the region. With growth of seismological and tectonic data, updated seismic hazard assessment is a worthwhile issue in emergency management programs and long-term developing plans in urban and rural areas of this region. In the present study, being armed with up-to-date information required for seismic hazard assessment including geological data and active tectonic setting for thorough investigation of the active and potential seismogenic sources, and historical and instrumental events for compiling the earthquake catalogue, probabilistic seismic hazard assessment is carried out for the region using three recent ground motion prediction equations. The logic tree method is utilized to capture epistemic uncertainty of the seismic hazard assessment in delineation of the seismic sources and selection of attenuation relations. The results are compared to a recent practice in code-prescribed seismic hazard of the region and are discussed in detail to explore their variation in each branch of logic tree approach. Also, seismic hazard maps of peak ground acceleration in rock site for 475- and 2,475-year return periods are provided for the region.  相似文献   

Lateral and depth variations of coda Q in the Zagros region of Iran     

Mohsen Ahmadzadeh Irandoust  Farhad Sobouti  Habib Rahimi 《Journal of Seismology》2016,20(1):197-211

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Steady state and liquefaction characteristics of gravely sands     

Seyed?Mohsen?Haeri  Amir?HamidiEmail author 《Geotechnical and Geological Engineering》2005,23(2):141-156

Liquefaction of loose and saturated soils during earthquakes and strong ground motions has been a major cause of damage to buildings and earth embankments as well as other civil engineering structures. In order to evaluate the liquefaction potential and steady state characteristics of gravely sand of south west Tehran,a subsoil exploration program conducted dividing the region into 10 zones. In each zone of 500 m × 500 m a borehole of 20 m deep was drilled. SPT was performed at one meter intervals in each borehole and a total of 200 samples were recovered. Soils of similar grain size distribution have been considered to have similar steady state characteristics,therefore consolidated undrained triaxial tests were performed on these soils of similar grain size distribution to evaluate the steady state strength. The steady state line for each soil type was derived. Comparing the steady state strengths with the shear stress due to an earthquake with a PGA of 0.35 g,the potential of sand liquefaction and .ow failure in soil layers has been evaluated and the settlement of soil due to the liquefaction phenomena is calculated. Finally some recommendations for estimating the steady state strength from simple SPT test in gravely sands are presented.  相似文献   

Experimental verification of sea-bed shear modulus profile inversions using surface gravity (water) wave-induced sea-bed motion     

Mark Trevorrow  Tokuo Yamamoto  Mohsen Badiey  Altan Turgut  Craig Conner 《Geophysical Journal International》1988,93(3):419-436

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A numerical technique for simulation of the effect of soil nitrogen transport and transformations on groundwater contamination     

Mohsen Mehran  Jahan Noorishad  Kenneth K. Tanji 《Environmental Geology》1983,5(4):213-218

Two numerical models, one for the vadose zone and the other for the aquifer system, are utilized to predict nitrate pollution potential in groundwater. Transport by dispersion and convection of mobile species of nitrogen, ammonium ion exchange, first order nitrogen transformations, and nitrogen plant uptake are included in the formulation for the vadose zone. Transport of nitrate in the aquifer is assumed to be affected only by dispersion-convection phenomena. Justifications for one-dimensional conceptualization of flow in the vadose zone and two-dimensional representation for the aquifer, under various field conditions, are presented. To illustrate the concept, a simple hypothetical problem is solved. The approach presented here provides an efficient means of long-term simulation of large-scale field problems.  相似文献   

Syn-depositional continental rifting of the Southeastern Neo-Tethys margin during the Albian–Cenomanian: evidence from stratigraphic correlation     

Amin Navidtalab  Mehdi Sarfi  Amirhossein Enayati-Bidgoli  Mohsen Yazdi-Moghadam 《International Geology Review》2020,62(13-14):1698-1723

ABSTRACT

Albian–Cenomanian successions (Kazhdumi and Sarvak formations) represent remarkable variations in thickness, facies, fauna, and environments throughout the Zagros area. In the Coastal Fars (Charmu section), sedimentological and paleontological data evidence an intrashelf, with depths of 10s–100s m, surrounded by a shallow carbonate platform. Due to its depth, deposition of sequences in this setting has been controlled by eustatic sea-level changes rather than eurybathic changes, and several condensation episodes occurred related to marine transgressions. These observations are different from those in the adjacent sections in the Coastal Fars which recorded subaerial exposures instead. Combined with previous studies, this study denotes several intrashelf basins enclosed by a shallow carbonate platform on the southeastern margin of the Neo-Tethys during the Albian–Cenomanian. Development of intrashelf basins corresponds to basement faults in the Fars Salient. Likely, an extensional tectonic regime associated with a rifting event created horst–graben architecture by exerting extension along the basement faults and reactivating salt structures. Deposition on these troughs and highs led to the facies and thickness variations of the concomitant sequences. Development of several intrashelf basins on the southeastern margin of the Neo-Tethys indicates that syn-depositional continental rifting event could occur during the Albian–Cenomanian, prior to the tectonic inversion around the earliest Turonian.  相似文献   

Backcasting long-term climate data: evaluation of hypothesis   总被引：1，自引：0，他引：1  

Bahram?SaghafianEmail author  Sara?Ghasemi?Aghbalaghi  Mohsen?Nasseri 《Theoretical and Applied Climatology》2018,132(3-4):717-726

Most often than not, incomplete datasets or short-term recorded data in vast regions impedes reliable climate and water studies. Various methods, such as simple correlation with stations having long-term time series, are practiced to infill or extend the period of observation at stations with missing or short-term data. In the current paper and for the first time, the hypothesis on the feasibility of extending the downscaling concept to backcast local observation records using large-scale atmospheric predictors is examined. Backcasting is coined here to contrast forecasting/projection; the former is implied to reconstruct in the past, while the latter represents projection in the future. To assess our hypotheses, daily and monthly statistical downscaling models were employed to reconstruct past precipitation data and lengthen the data period. Urmia and Tabriz synoptic stations, located in northwestern Iran, constituted two case study stations. SDSM and data-mining downscaling model (DMDM) daily as well as the group method of data handling (GMDH) and model tree (Mp5) monthly downscaling models were trained with National Center for Environmental Prediction (NCEP) data. After training, reconstructed precipitation data of the past was validated against observed data. Then, the data was fully extended to the 1948 to 2009 period corresponding to available NCEP data period. The results showed that DMDM performed superior in generation of monthly average precipitation compared with the SDSM, Mp5, and GMDH models, although none of the models could preserve the monthly variance. This overall confirms practical value of the proposed approach in extension of the past historic data, particularly for long-term climatological and water budget studies.  相似文献   

Soil organic carbon stock as affected by land use/cover changes in the humid region of northern Iran     

Samereh FALAHATKAR  Seyed Mohsen HOSSEINI  Abdolrassoul SALMAN MAHINY  Shamsollah AYOUBI  WANG Shao-qiang 《山地科学学报》2014,11(2):507-518

This study was conducted to determine the changes in the soil carbon stocks as influenced by land use in a humid zone of Deylaman district(10,876 ha), a mountainous region of northern Iran. For this, land use maps were produced from TM and ETM+ images for 1985, 2000 and 2010 years; and this was supplemented by field measurement of soil carbon in 2010. The results showed that the mean soil organic carbon(SOC) density was 6.7±1.8 kg C m-2, 5.2±3.4 kg C m-2 and 3.2±1.8 kg C m-2 for 0-20 cm soil layer and 4.8±1.9 kg C m-2, 3.1±2 kg C m-2 and 2.7±1.8 kg C m-2 for 20-40 cm soil layer in forest, rangeland and cultivated land, respectively. During the past 25 years, 14.4% of the forest area had been converted to rangeland; and 28.4% of rangelands had been converted to cultivated land. According to the historical land use changes in the study area, the highest loss of SOC stocks resulted from the conversion of the forest to rangeland(0.45×104 Mg C in 0-40 cm depth layer); and the conversion of rangeland to cultivated land(0.37×104 Mg C in 0-40 cm), which typically led to the loss of soil carbon in the area studied. The knowledge on the historical land use changes and its influence on overall SOC stocks could be helpful for making management decision for farmers and policy managers in the future, for enhancing the potential of C sequestration in northern Iran.  相似文献