Evaporation losses and dispersion of volatile organic compounds from tank farms

© 2015, Springer International Publishing Switzerland. The present study is an application of a Gaussian dispersion model to evaluate volatilization losses from tank farms. It reports methodology to estimate evaporation losses of volatile organic compounds (VOCs) from organic liquid in storage tanks. This study used fixed roof and floating roof equations for breathing and working losses. Total loss, the breathing loss, vapor pressure, molecular weight of the product, tank diameter, diurnal temperature, paint factor, tank capacity, and number of turnovers were considered and factored in the calculation. AERMOD and ALOHA softwares were used to simulate the dispersion of VOCs under normal and accidental scenarios. For the modeling purposes, meteorological data such as annual average ambient temperature, annual average atmospheric pressure, daily minimum ambient temperature, daily maximum ambient temperature, solar insulation factor, and average wind speed were included as input in the calculation and modeling activities. The study took place in Sharjah Emirate in United Arab Emirates, which borders Dubai to the south and Ajman to the north, and the three form a conurbation. The reported method was used to estimate evaporation losses for baseline and hypothetical leak scenarios. Results of this research show that liquid storage tanks in the study area emit a low concentration of VOC under the studied and assumed conditions, e.g., new tanks with high performance sealing as well as the noted earlier climatic conditions. The dispersion of those concentrations is controlled by the prevailing wind direction. The predicted VOCs concentrations were within the range of the measured VOCs values in air. The study found that the spatial distributions of the predicted concentration attenuate with time and distance. Under the reported accidental spill scenario, the Gaussian model indicates that the danger area starts within the zone of less than 10 m. The danger area is subjected to flame pockets, and the VOC concentrations in this area will exceed 19,800 ppm

The knowledge and practice of workers toward occupational hazards: Case study from United Arab Emirates

© 2017, Universidade Federal do Rio de Janeiro. All rights reserved. The focus of this investigation is to assess the level of knowledge, attitude and practice (KAP) of workers on occupational health and safety issues in the industrial town of Mussafah, United Arab Emirates. A combination of personnel interviews in conjunction with t-test and logistic regressions were used to assess the KAP of the workers. Around 98% of the survey results indicate that the computed p-value of the responses is greater than the significance level alpha = 0.05, hence the null hypothesis H0 of the test of normality cannot be rejected. The risk to reject the null hypothesis H0 while it is true ranges 77.86% to 99%. The study revealed that there is an overall low awareness of health and safety issues among the studied sample. This therefore makes the workers generally more susceptible to accidents. Results have also shown that 48% of the managers were aware of the hazards taking place at their facilities, and 42.6% of them knew the possible harmful effects from their industrial processes. In terms of the health considerations of the visited sites, 55% of the workers were unaware about it and 48% of them rarely used their given protective equipment. The present study indicates the education level and years of experience did not impact the practices. The results have shown the need for training programs to build the capacity of workers in the field of health and safety

The application of narrow-band NDVI as a tool for mapping mangrove environment in Abu Dhabi

© 2017 ACM. The overall utility of a visible/near infrared images and spectral profiles has several advantages and applications in environmental and ecosystem investigations. In the present paper, a close-range remote-sensing technique is used for assessing algal communities within the sabkha environment. The area is partially covered by mangrove trees and has salt at areas without visible algal mat. Other locations have dark brown and green patches of algae especially in the supratidal area. Those considered as the most important organisms living in the sabkha habitat. Visible and infrared electromagnetic bands were used to characterize productivity, biomass, and distribution of the algal communities in the sabkha environment. To accomplish this, the study tested the use of the well-documented ratio of near-infrared (NIR; 800nm) to red (670nm) reflectance in order to characterize the living component in the Sabkha area of Abu Dhabi. Multispectral visible/Near Infrared camera was used to collect images from the area of interest. The reported analysis characterized two types of algae; namely active and non-active algae. The active algea has high near-infrared (NIR) band reflectance and lower red band reflectance. However, inactive algea has low NIR band reflectance and higher Red band reflectance. The study also reported field observations, computer vision approach and remote sensing indicators that are useful in order to study the relation between spectral reflectivity and algal characteristics

Gravity investigations of recent sinkholes and karst pits of Dahal Al-Hamam, State of Qatar

© 2016, Springer-Verlag Berlin Heidelberg. Gravity prospecting is a very useful geophysical technique for the investigation of karst subsurface features, in urban areas, which are a common natural hazard in several parts of the world. Gravity data were used to determine the subsurface conditions in central Qatar to map zones vulnerable to sinkhole formation in the vicinity of Dahel Al-Hamam area in the State of Qatar. Gravity modeling was a useful technique to map the spatial extension of the karts topography associated with these sinkholes. Clusters of closely spaced contours of low gravity values observed in the northeastern part of the studied area are indicative of relatively very low negative anomaly which points to missing mass due to karst processes. This was interpreted as either as an air-filled or water-filled sinkhole. The obtained video images of the subsurface features of the studied area confirmed that the existing subsurface caves are water filled. The extension of the sinkhole and associated openings are connected to the Arabian Gulf. To prevent the growth of associated underground cavities, the bibliographical research indicated that filling up the uppermost voids with stable grout mix is one of the appropriate treatment options to help reduce the macro-permeability of the rock and to prohibit the migration of the favorable conditions of cavity formation. The findings have both local and general applications. Locally, the findings delineate the subsurface extension of the karst topography, and it is generally demonstrated that non-invasive surveying methods constitute a useful tool to enhance knowledge on sinkhole phenomenon

Assessment of heavy metals in roadside dust along the Abu Dhabi–Al Ain National Highway, UAE

© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. Concentrations of key heavy metals (Pb, Zn, Cd, Ni, Cr, Mn, As, and Hg) have been investigated in roadside dust collected from Abu Dhabi–Al Ain National Highway in UAE. The heavy metals contents were analyzed by atomic absorption spectrometer. Heavy metal levels varied widely from 227.9 to 2765, 19 to 1540, 37.4 to 398.6, 20.1 to 123, 0.3 to 0.7, 0.1 to 0.9, 0.1 to 0.7, and 0.1 to 0.5 mg/kg for Mn, Cr, Zn, Pb, Cd, Hg, Ni, and As, respectively. The spatial distribution pattern showed that different sources of roadway metal emissions dominate at specific locations. Peaks in heavy metal concentrations were frequently observed in locations with high traffic volume, road intersections and junctions, gas and bus stations. Decreased levels of heavy metals were measured in locations with low traffic loadings and in close proximity to farm and forest areas. In addition to traffic-related heavy metals, emissions from fossil fuel and industries remain of significance. Natural sources, through regular dust storms, are important contributors to the observed metal levels. Enrichment factor indicated that As and Ni were entirely originated from crustal sources. Cd, Zn, Pb, and Mn were moderately enriched and are probably derived from mixed sources (traffic flows, gas stations, construction and agricultural activities, among others). Road dust was significantly enriched in Cr and Hg indicating their dominant anthropogenic origin. The average geo-accumulation index values suggested that road dust are uncontaminated with Mn, Ni, and As, uncontaminated to moderately contaminated with Zn and Pb, and moderately contaminated with Cr, Cd, and Hg. The contamination factors indicated very highly contaminated road dust with Cr and Hg, considerably contaminated with Cd, and moderately contaminated with Mn, Zn, and Pb. Results of ecological risk assessment revealed that all heavy metals in road dust pose low risk to local ecosystems, except for Cd and Hg, which constitute potentially considerable risk and high risk, respectively

Baseline marine investigation and impact of fish farming on the marine environment in Jebel Ali, Dubai, United Arab Emirates

© 2020 Scattered seashells were observed on the seabed with no marine corals. The baseline studies indicate that biodiversity decreased from the northeast to southwest direction. The dominant groups of phytoplankton were diatoms followed by dinoflagellates, with insignificant vertical variations in species composition and population due to shallow water. The benthic diversity over the majority of the study area was relatively low compared with other nearshore areas in the region. All subtidal habitats showed evidence of disturbance to varying degrees, with no fish species recorded at these locations. The soft sediment habitat was found to cover much of the area footprint, and faunal diversity was very low. Fish diversity and abundance were equally poor with only a few demersal species recorded. No evidence of coral colonization was recorded although the presence of a low-profile, encrusting species was recorded in close proximity, to the east of the study area. Mangrove, coral, and seagrass were absent in the study area and its immediate vicinity. Modelling of waste plume suggested that the harbor water is fairly well-mixed, and the dispersion of ammonia attenuates with distance

Hapke-based computational method to enable unmixing of hyperspectral data of common salts

© 2018, The Author(s). Environmental scientists are currently assessing the ability of hyper-spectral remote sensing to detect, identify, and analyze natural components, including minerals, rocks, vegetation and soil. This paper discusses the use of a nonlinear reflectance model to distinguish multicomponent particulate mixtures. Analysis of the data presented in this paper shows that, although the identity of the components can often be found from diagnostic wavelengths of absorption bands, the quantitative abundance determination requires knowledge of the complex refractive indices and average particle scattering albedo, phase function and size. The present study developed a method for spectrally unmixing halite and gypsum combinations. Using the known refractive indexes of the components, and with the assistance of Hapke theory and Legendre polynomials, the authors develop a method to find the component particle sizes and mixing coefficients for blends of halite and gypsum. Material factors in the method include phase function parameters, bidirectional reflectance, imaginary index, grain sizes, and iterative polynomial fitting. The obtained Hapke parameters from the best-fit approach were comparable to those reported in the literature. After the optical constants (n, the so-called real index of refraction and k, the coefficient of the imaginary index of refraction) are derived, and the geometric parameters are determined, single-scattering albedo (or ω) can be calculated and spectral unmixing becomes possible

C–O isotope geochemistry of the Florida phosphate of Four Corners and Hardee County mines, USA: Implication for genesis and diagenesis

© 2017 Elsevier B.V. The study area located in Florida, USA and emphasized on low-grade phosphorites in Hardee County (HC) and Four Corners (FC) mining areas. The main purpose of this study is to apply a standard geochemical technique to understand the diagenetic history and paleo-environmental aspects of phosphates within one of the major phosphate deposits in the USA. The effect of diagenesis on the phosphate minerals was studied by isotope analysis of the phosphate bone fragments and phosphatized mudclasts and rods. The environmental conditions that prevailed during the life of organisms were assessed by isotope analysis of the shark teeth. In this paper, variation in stable isotope (δ18O and δ13C) signatures of structural carbonate in rocks and shark teeth were studied in Florida phosphate. The studied samples show negative values for both δ13C and δ18O isotopes of structural carbonate. The light mudclast samples shows higher oxygen ratios (− 1.6) than the dark mudclasts (− 2.3) in Hardee County, whereas those values were lower, − 2.3 and − 3, respectively, in Four Corners samples. The shark teeth found in the deposits show narrow variations in values of δ13C (− 3.4 to − 4.9%o) and δ18O (− 1.4 to 2.1%o) isotope. The bone fragments in the deposits are more similar to the light mudclasts regarding the isotope ratios and carbonate content. The alteration is evident in the Florida phosphorites where δ18O values of bulk teeth are higher than those of bones and mudclast. This alteration could be because of increasing crystallinity and decreasing carbonate content with increasing depth of burial

Use of remote sensing data in assessment land cover changes, land use patterns and land capabilities in AL-Qassim region, Saudi Arabia

© 2017 by International Journal of Ecology & Development. The Qassim region of central Saudi Arabia is one of the most important agricultural regions in the country especially for date cultivation. In the present study, Land sat TM and ETM+ data for the period 1999-2013 are used to study the land use, land cover changes in the area. Satellite images from path/row 168/042 constitute the study area. Three major land use/land cover classes are considered: hilly areas (364,407 ha), vegetated land (1,776,698 ha), and sand dunes (1,523,669 ha). The vegetated land constitutes the class 1, which is comprised of the wades mainly devoted used for for date production. Sand dunes are designated the class 11 and covered a large portion of the study area whereas the Hilly areas are unproductive and constitute as class 111.The vegetative land are surrounded by sand dune which is the most fragile system of the area and leads to damage some productive lands in the area. It is necessitates to study the area for suitable land management practices and for possible approach to stop the sand drifting or sand encroachment in the area. The land use capabilities classification of the study area includes three main classes: LUC I, LUCII, and LUC III. Slopes ranging between 0°and 20°correspond to areas that areflat, gently undulating, undulating, rolling, strongly rolling, moderately steep and steep, respectively. The slope categories dictate the usage patterns of the lands in the study area, which range from suitable to unsuitable to productive lands