Evaluation of groundwater quality in northern Saudi Arabia using multivariate analysis and stochastic statistics   总被引：1，自引：0，他引：1  

Abeer Sh. Salman  Faisal K. Zaidi  M. T. Hussein 《Environmental Earth Sciences》2015,74(12):7769-7782

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Risk Assessment of Radon Exposure by Ingestion and Inhalation of Groundwater Within Different Age Groups     

Al Mamun  Amira Salman Alazmi 《Ground Water Monitoring & Remediation》2023,43(1):69-77

Radon and its short-lived progeny are exposed to most human exposures as a natural source of radiation. Many studies have presumed that one of the most common incidences of lung cancer, colon cancer, and stomach cancer is caused by radon-contaminated water. In this study, water was collected from different groundwater sources in the Hafr Al Batin area, Saudi Arabia, and the radon concentration was investigated using an electronic portable radon detector. The annual effective dose of radon exposure by ingestion and inhalation of water is calculated from that radon concentration for the different age groups to assess the risk of radon exposure. The calculated annual effective doses are then compared with the international standard of risk limit as directed by the international organizations. The estimated radon concentration for groundwater samples is found to be between 0.03 and 3.20 Bq/L with an average value of 1.16 Bq/L. These estimated values are below the safety limits set by the USEPA and EAEC and far below those recommended by the UNSCEAR, EC, and WHO standards. The calculated annual effective dose of radon exposure for the different age groups ranging from infant to adult is found to be in the range of 0.05 to 16.24 μSv/year, with a mean value of 5.89 μSv/year, which is in the safe limit recommended by the EC and WHO. The obtained results of this present study will support the authority and regulators who are responsible for controlling and strategizing to ensure public safety against radon exposure.  相似文献   

Multivariate and principal component statistical analysis of contamination in urban and agricultural soils from north Jordan   总被引：1，自引：0，他引：1  

S. R. Salman  Y. H. Abu Ruka'h 《Environmental Geology》1999,38(3):265-270

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Assessment of changes in urban green spaces of Mashad city using satellite data     

Reza Rafiee  Abdolrassoul Salman Mahiny  Nematolah Khorasani 《International Journal of Applied Earth Observation and Geoinformation》2009

Green spaces play important functions in urban environments. Reducing air pollution, providing shade and habitat for arboreal birds, producing oxygen, providing shelter against winds, recreational and aesthetic qualities and architectural applications are the main functions of urban green spaces. With the rapid change of urban area in Mashad city during the past decades, green spaces have been fragmented and dispersed causing impairment and dysfunction of these important urban elements. The objective of this study was to detect changes in extent and pattern of green areas of Mashad city and to analyze the results in terms of landscape ecology principles and functioning of the green spaces. In this research, we classified a Landsat TM and an IRS LISS-III image belonging to the years 1987 and 2006, respectively. We then used a post-classification comparison to determine the changes in green space areas of Mashad city during the 19 years covered by the images. Then, we applied landscape ecology calculations to derive metrics that quantified pattern of the changes in the green areas. The results showed that during 19 years from 1987, a significant decrease had occurred in the extent of urban green spaces with a concomitant fragmentation resulting in downgrading and destruction of the functions and services these areas provide. We conclude that the general quality of life in the central parts of the city has been diminished. We also state that a combination of remote sensing image classification, landscape metrics assessment and vegetation indices can provide a tool for assessing life quality and its trend for urban areas.  相似文献   

Practical finite analytic methods for simulation of advection-dominated solute transport     

M. Salman Sabahi  Hanif Montazeri  Mojtaba Ardestani  Brent Sleep 《水文科学杂志》2013,58(12):2204-2213

Abstract

The practical finite-analytic (PFA) method was applied to the solution of the one-dimensional advection–dispersion equation (ADE) for solute transport in porous media under advection-dominated (high Peclet number, Pe) conditions. Several PFA spatial-temporal computational molecules were developed for Cauchy and pulse loading boundary conditions. The PFA solutions were compared with solutions from the upwind method and quadratic upwind differencing (QUICK) scheme. For all boundary conditions the trapezoidal explicit PFA (EPFA) computational molecule gave the most accurate results at very high Pe number as long as the Courant number (Cr) was close to one. Stability analysis shows that the PFA molecules are always stable for high Pe number.  相似文献   

Studies of clump structure of photodissociation regions at millimeter and sub-millimeter wavelengths     

Abdul Qaiyum  Syed Salman Ali 《Journal of Astrophysics and Astronomy》2003,24(3-4):69-83

To interpret the millimeter and sub-millimeter line emissions of atomic and molecular species from galactic and extragalactic photodissociation regions, warm gas components and molecular clouds, generally, escape probability formalism of Tielens & Hollenbach (herein referred as TH) are employed which is based on the assumption of plane parallel geometry of infinite slab allowing photons to escape only from the front. Contrary to the assumption observationally it is found that these lines are optically thin except OI(63μ m) and low rotational transitions of CO and some other molecules. This observational evidence led us to assume that emitting regions are finite parallel plane slab in which photons are allowed to escape from both the surfaces (back and front). Therefore, in the present study escape of radiations from both sides of the homogeneous and also clumpy PDR/molecular clouds are taken into consideration for calculating the line intensities at millimeter and sub-millimeter wavelengths (hereinafter referred as QA). Results are compared with that of the TH model. It is found that thermal and chemical structures of the regions are almost similar in both the formalisms. But line intensities are modified by differing factors. Particularly at low density and low kinetic temperature and also for optically thin lines line intensities calculated from TH and QA model differ substantially. But at density higher than the critical density and also for optically thick lines TH and QA models converge to almost same values. An attempt has been made to study the physical conditions of the M17 region employing the present formalism.  相似文献   

Chandra and XMM–Newton detection of large-scale diffuse X-ray emission from the Sombrero galaxy     

Zhiyuan Li  Q. Daniel Wang  Salman Hameed 《Monthly notices of the Royal Astronomical Society》2007,376(3):960-976

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Heavy metal contamination in surface sediments of Gökçekaya Dam Lake,Eskişehir,Turkey     

Beril Salman Akin  Oğulcan Kırmızıgül 《Environmental Earth Sciences》2017,76(11):402

The present study to find seasonal (September 2010–June 2011) heavy metal (Cd, Pb, Cr, Co, Ni, Zn, Cu, Fe, As) contamination and the origins thereof in surface sediments of Gökçekaya Dam Lake, as constructed on Sakarya River, the third-longest river in Turkey and the largest river of the Northwestern Anatolia. Upon analyses for the purpose thereof, heavy metal contamination in annual average concentrations in the lake sediment varied, respectively, as Fe > Zn > Cr > Ni > Cu > Pb > Co > As > Cd. Statistical assessments performed in order to see whether the average values of the heavy metal contamination as measured at stations placed in the lake changed by seasonal periods. There found statistically significant differences especially in Cd, Zn, and Pb between seasonal periods. In accordance with the Sediment Quality Index, Gökçekaya Dam Lake sediment was classified as “highly polluted” in terms of the amount of anthropogenic contaminants of As, Cr, Cu, Ni, Pb, and Zn. Enrichment factor and geoaccumulation index values (I _geo) were calculated in order to geochemically interpret the source of contamination due to heavy metal concentration in the lake sediment and the level of pollution. The As, Co, Cr, Cu, Ni Pb, and Zn values demonstrated that the sediment was rich for anthropogenic contaminants. The lake was found especially rich for arsenic (14.97–34.70 mg/kg) and lead (68.75–98.65 mg/kg) in accordance with annual average values. In general the lake was geochemically characterized as “moderately contaminated” in terms of As, Co, Cr, Cu, Ni, Pb, and Zn content.  相似文献   

Image data fusion for the remote sensing of freshwater environments   总被引：2，自引：0，他引：2  

Salman Ashraf  Lars BrabynBrendan J. Hicks 《Applied geography (Sevenoaks, England)》2012,32(2):619-628

Remote sensing based mapping of diverse and heterogeneous freshwater environments requires high-resolution images. Data fusion is a useful technique for producing a high-resolution multispectral image from the merging of a high-resolution panchromatic image with a low-resolution multispectral image. Given the increasing availability of images from different satellite sensors that have different spectral and spatial resolutions, data fusion techniques that combine the strengths of different images will be increasingly important to Geography for land-cover mapping. Different data fusion methods however, add spectral and spatial distortions to the resultant data depending on the geographical context; therefore a careful selection of the fusion method is required. This paper compares a technique called subtractive resolution merge, which has not previously been formally tested, with conventional techniques such as Brovey transformation, principal component substitution, local mean and variance matching, and optimised high pass filter addition. Data fusion techniques are grouped into spectral and spatial centric methods. Subtractive resolution merge belongs to a new class of data fusion techniques that uses a mix of both spatial and spectral centric approaches. The different data fusion techniques were applied to a QuickBird image of a semi-aquatic freshwater environment in New Zealand. The results were compared both qualitatively and quantitatively using spectral and spatial error metrics. This research concludes that subtractive resolution merge performed better than all the other techniques and will be a valuable technique for enhancing images for freshwater land-cover mapping.  相似文献   

Emission quantification of refrigerant CFCs,HCFCs and HFCs in megacity Lahore (Pakistan) and contributed ODPs and GWPs     

Zia Ul-Haq  Muhammad Ali  Syeda Adila Batool  Salman Tariq  Zarmina Qayyum 《Journal of Earth System Science》2016,125(6):1273-1284

An integrated assessment of emissions of some important refrigerant ozone depleting substances (ODSs) (CFC-11, CFC-12, HCFC-141b and HFC-134a) and their contributed ozone depletion potentials (ODPs) and global warming potentials (GWPs) have been made in the megacity Lahore (Pakistan) for the period from 2005 to 2013. During the production of 6.488 million refrigerator units, the cumulative estimated emissions of CFC-11, CFC-12, HCFC-141b and HFC-134a were 129.7, 6.8, 1257 and 104 mega grams (1 Mg = 10⁶ grams). The estimated GWP (CO₂-eq) and ODP (CFC 11-eq) associated with production phase emissions of these four gases were 616.07, 73.52, 910.96, and 87.36 kilotonnes, and 129.7, 6.8, 139.4, and 0 tonnes, respectively. ODP of HFC-134a is considered to be zero. In addition, the repair and maintenance of 81.2 thousand units resulted in 10.8 Mg emissions of CFC-12 with 10.8 tonnes ODP(CFC 11-eq) and 117,802 tonnes GWP (CO₂-eq) that were higher than the HFC-134a emissions recorded at 4.3 Mg causing 4563 tonnes GWP(CO₂-eq). A decrease in ODP (CFC 11-eq) and GWP (CO₂-eq) at the rate of ?8.3% and ?8.2% per year is observed to be contributed by all the selected ODSs during the study period.  相似文献