Environmental assessment of soil,groundwater, and surface water quality in the south of the Riyadh,Saudi Arabia

To understand the impact of the influence of treated wastewater, a study was undertaken in the downstream side of Wadi Hanifa in the southern part of Riyadh City in Saudi Arabia. Chemical elements from 17 groundwater samples, 9 surface water samples (treated wastewater), and 14 soil samples were analyzed. Water facies analyses showed that both groundwater and surface water belong to the SO₄-Cl class. However, the groundwater is characterized by high salinity (average value of 3547 mg/l), which may be result of the greater rock-water interaction and limited rainfall recharge. The NO₃ values are also high in the groundwater samples (average value of 40 mg/l) and are mainly attributed to the agricultural practices in the study area. The surface water samples (treated wastewater from the plant) shows an average salinity value of 1232 mg/l and is better suited for irrigation purposes. Heavy elements analyzed in the soil samples show high concentrations of all the elements except Mn and Ni as compared to their background concentration. Enrichment factor and index of geoaccumulation calculated from the soil samples indicate that they are severely enriched with respect to Cd and Se. The spatial distribution maps were prepared based on kriging interpolation technique to estimate the concentrations of the analyzed elements at unknown locations. The treated wastewater in the study area is better suited for agricultural and domestic activities as compared to groundwater.     

Helical Eruptive Prominence Associated with a Pair of Overlapping CMEs on 21 April 2001

The eruption of limb prominence on 21 April 2001 associated with two coronal mass ejections (CMEs) is investigated. Hα images reveal two large-scale eruptions (a prominence body and a southern foot-point arch), both showing helical internal structure. These two eruptions are found to be spatially and temporally associated with the corresponding CMEs. The kinematics and the study of geometrical parameters of the prominence show that the eruption was quite impulsive (with peak acceleration ≈470 m s⁻²) and has taken place for relatively low pitch angle of helical threads, not exceeding tan θ≈1.2. The stability criteria of the prominence are revisited in the light of the model of Vršnak (1990, Solar Phys. 129, 295) and the analysis shows that the eruption violates the instability criteria of that model. Finally, the energy stored in the prominence circuit and the energies (kinetic, potential, and magnetic) of the associated CMEs are estimated and it is found that there was enough energy stored in the prominence to drive the two CMEs. S.S. Ali is on leave from Aligarh Muslim University, Aligarh, 202 002, India.     

Study of a large helical eruptive prominence associated with double CME on 21 April 2001

Here we present a preliminary analysis of a helical eruptive prominence at the east limb of the Sun on 21 April 2001. Unusually this eruption is associated with a double CME. We have tried to study the morphology of the event, energy budget of the prominence and associated CMEs. Our analysis shows that the prominence and first CME started simultaneously from the limb and prominence carries sufficient energy to feed both the CMEs. Moreover, it is also concluded that CMEs are magnetically driven and internally powered.     

Water vapour mixing ratio profiles over Hornsund, Arctic. Intercomparison of lidar and AIRS results

Since October 2009, a ground-based Raman lidar system has been deployed to perform a regular, night-time, vertical sounding of a water vapour content in the lower and middle troposphere above Polish Polar Station at Hornsund (77.00°N, 15.55°E, 10 m a.s.l.) in the Arctic. The water vapour mixing ratio profiles were obtained for the atmosphere up to 6 km altitude, based on analysis of inelastic Raman backscattering signals from nitrogen molecules (at 387 nm) and water vapour particles (at 407 nm), calibrated with the data from a local Vaisala’s automatic meteorological station. The results obtained for winter seasons in the years 2009–2012 are in a good general agreement with the results obtained from the atmospheric infrared sounder (AIRS) on the Aqua satellite.     

Integrated mass balance of some heavy metals fluxes in Yaakob village,south Sohag,Egypt

The pollution of soil with heavy metals has direct or indirect adverse effect on human health. The present work was conducted to identify all the expected sources and sinks for heavy metals by applying mass balance model to identify the retention rate of metals by soils in Yaakob village, south Sohag Governorate, Egypt. The studied inputs (sources) include P-fertilizers, irrigation water and dustfall, while the main outputs (sinks) are drainage water and harvested plants. The measurements indicate that soil, clover, dustfall and P-fertilizers contain considerable concentration of Cd, Cr, Co, Cu and Pb. The mass balance measurements indicate that the accumulation rate of Cd, Cr and Co in soil was 5.4, 54.6 and 16.3 g ha^?1 year^?1, respectively. However, depletion trend of Pb and Cu was about 1.4 and 5.2 g ha^?1 year^?1, respectively. The main source of Cd, Pb, Cr and Co in the study area is P-fertilizers with input flux 14.9, 89.9, 198.6 and 18.5 g ha^?1 year^?1, while Cu source was dustfall with 19.33 g ha^?1 year^?1. The index of geoaccumulation calculations indicates different degrees of contamination with Cd, Cr, Co and Cu. On the other hand, the main sink for the studied heavy metals was the Egyptian clover (Trifolium alexandrinum) which can be considered a good bioaccumulator of heavy metals.     

Siting MSW landfills with a weighted linear combination methodology in a GIS environment

Landfill has been taken to the bottom of the hierarchy of options for waste disposal but has been the most used method for urban solid waste disposal. However, landfill has become more difficult to implement because of its increasing cost, community opposition, and more restrictive regulations regarding the siting and operation of landfills. Land is a finite and scarce resource that needs to be used wisely. Appropriate allocation of landfills involves the selection of areas that are suitable for waste disposal. The present work describes a type of multi-criteria evaluation (MCE) method called weighted linear combination (WLC) in a GIS environment to evaluate the suitability of the study region for landfill. The WLC procedure is characterized by full tradeoff among all factors, average risk and offers much flexibility than the Boolean approaches in the decision making process. The relative importance weights of factors are estimated using the analytical hierarchy process (AHP). In the final aggregated suitability image, zones smaller than 20 hectares are eliminated from the allocation process. Afterwards, the land suitability of a zone is determined by calculating the average of the suitability of the cells belonging to that zone, a process called zonal land suitability. The application of the presented method to the Gorgan city (Iran) indicated that there are 18 zones for landfill with their zonal land suitability varying from 155.426117 to 64.149024. The zones were ranked in descending order by the value of their zonal land suitability. The results showed the use of GIS as a decision support system (DSS) available to policy makers and decision makers in municipal solid waste (MSW) management issues.     

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

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.