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Evaporation is one of the vital components of hydrological cycle. Precise estimation of pan evaporation (Epan) is essential for the sustainable water resources management. The current study proposed a novel approach to estimate daily Epan across the humid region of Iran using support vector regression (SVR) technique coupled with Krill Herd Algorithm (SVR-KHA). Meteorological data were collected from three stations (Bandar Abbas, Rudsar, and Osku) over a period from 2008 to 2018 and used for application. Of the data, 70% were used for training and remaining 30% were used for testing. The study considered seven different combinations of input variables for predicting daily Epan at each station. The influence of KHA hybridization is examined by comparing results of SVR-KHA algorithm with simple SVR through a multitude of statistical performance evaluation criteria such as coefficient of determination (R2), Wilmot’s index (WI), root-mean-square error (RMSE), Mean Absolute Error (MAE), Relative Root Mean Square Error (RRMSE), Mean Absolute Relative Error (MARE), and several graphical tools. Single input SVR1 model hybrid with KHA (SVR-KHA1) showed improved performance (R2 of 0.717 and RMSE of 1.032 mm/day) as compared with multi-input SVR models, e.g., SVR5 (with RMSE and MAE of 1.037 mm/day and 0.773 mm/day), while SVR7 model hybridized with KHA (SVR-KHA7), which considers seven meteorological variables as input, performed best as compared with other models considered in this study. Epan estimates at Bandar Abbas and Rudsar by SVR and SVR-KHA are similar (with R2 statistics values of 0.82 and 0.84 at Bandar Abbas station, and 0.88 and 0.9 at Rudsar station, respectively). However, better improvements in Epan estimates are observed at Osku station (with R2 of 0.91 and 0.86, respectively), which is situated at interior geographical location with a higher altitude than the other two coastal stations. Overall, the results showed consistent performance of SVR-KHA model with stable residuals of lower magnitude as compared with standalone SVR models.

Rainwater harvesting (RWH), which is the collection and storage of rainwater for multiple purposes, is gaining recognition in water supply issues. Selection of harvesting sites is the most critical...

Landfill leachate is currently a major environmental concern because it contains high concentrations of organic and inorganic contaminants. Leachate treatment using natural materials, such as aquifer sand, peat, and the commercial material BIRM (Burgess Iron Removal Media), was performed through column experiments. Aquifer sand was taken from Kg Teluk, Kelantan, peat was taken from Peatland Paradise, and BIRM was bought from a supplier. The heavy metals (Fe3+, Cr, Ni, and Cu) from natural leachate were selected for this experiment. The concentrations of Fe, Cr, Ni, and Cu before the experiment were 11, 1.27, 4.535, and 3.293 mg L–1, respectively. The physical and chemical parameters of leachate and surface water at the Taman Beringin Landfill have been studied to understand the impact of pollution in the area. The results show that leachate samples at the bottom of the landfills have the highest pollution. Both the physical and chemical parameters of leachate exceed the limits of Interim National Water Quality Standards for Malaysia. Experimental test results were also analyzed in terms of breakthrough curves and percentage of heavy metal removal. The results show that the BIRM sample has a higher adsorption capacity for heavy metals, including Fe, compared with aquifer sand and peat.

The watershed hydrological process is mostly influenced by land use and climate changes. The present study evaluates the relative contribution of land use and climate changes to runoff change in Rawal and Simly watersheds of Pakistan. The Mann Kendall and Pettit tests are used to find the trends and change points in the hydro-meteorological variables (runoff and precipitation) during 1983–2012. Two different models, including HEC-HMS and abcd hydrological models, are used to assess the impact of climate and land use changes on runoff. The results of both techniques were in good agreement. An increasing and decreasing trends in runoff were observed in Rawal and Simly watersheds, respectively. The runoff in Rawal watershed increased by 21.36 mm due to climate change and by 17.44 mm due to land use change. On the other hand, decrease in runoff across Simly watershed is 210.1 mm and 161.1 mm due to climate and land use changes, respectively. The relative contributions of climate and land use changes are around 55.1–56.9% and 44.9–43.4% in Rawal and Simly watersheds, respectively. The present study concludes that both climate and land use changes have a significant impact on the runoff of Margalla Hills, which could be considered for better water resources management.

Groundwater reservoirs are important water resources all over the world. Especially, they are of utmost significance for arid and semi-arid regions, and therefore, a sustainable exploitation of these reservoirs needs to be ensured. The natural and most exclusive water supplier to groundwater reservoirs in Saudi Arabia is rainfall, which is characterized by sporadic and random temporal and spatial distributions, particularly under the impacts of climate change; giving rise to uncertainty in groundwater recharge quantification. Although in Saudi Arabia, intense and frequent rainfall events are rare, but they generate significant flash floods with huge amounts of surface water. Under such circumstances, any simple but effective water storage augmentation facility such as rainwater harvesting (RWH) structures gain vital importance for sustainability of water supply and survivals in arid and semi-arid regions. The objective of this study is to explore the possibility of RWH over a basin in the western province of Saudi Arabia called Wadi Al-Lith under climate change. Climatic data is obtained from the IPCC AR5 GCMs, which is further downscaled using a regional climate model RegCM4 for the Arabian Peninsula domain. The RegCM4 is driven to simulate climatic parameters including rainfall at 25 km grid resolution for the present climate (1971–2000), and future climate (2006–2099) with representative concentration pathways, RCP4.5 and RCP8.5. Results indicate that more durable and longer wet durations are expected with increasing surplus rainfall amounts in the far future because of climate change impacts. Consequently, future climate scenarios are expected to enhance floods and flash floods occurrences, which call for progressive measures to harness the RWH opportunity.

Accounting for more than 16% of the world’s net electricity production, hydropower is one of the most commonly used renewable sources of energy. Small-scale hydropower (SSH) systems are becoming increasingly successful options for hydropower generation, particularly in small localities and remote areas. Regardless of its low capacity, small-scale hydropower produces cheap, clean, and reliable electricity. The objective of this study is to provide a sustainable and economical solution for the increasing demand of electricity through small-scale hydropower generation in Pakistan. River flow and low head potential were investigated at twenty sites along the Upper Swat Canal and Swat River for hydropower generation. The sites were selected based on large differential head, velocity, ease of access, close proximity to dense population, and structural support. Hydropower capacity was calculated for each site based on the collected flow and hydraulic data. The cost per kW h of energy generated has been estimated by dividing the average annual recurring cost with annual generation over the lifetime of the project. Cost analysis indicated that purchasing one unit at 0.04 US$ is suitable for both the consumer and the government. Results revealed that each site is qualified to provide stable energy to more than 1500 houses based on the maximum consumption per home. The cost of the proposed power system was identified as the incentive factor in this study. In addition to the minimal variation in the seasonal production, the studied sites produced as much as 21% of the total Swat River production. The proposed spatial power distribution scenarios have contributed a potentially flexible alternative and cost-effective solution to the proposed SSH system.

The accumulation and factors affecting Poly 3-hydroxybutyric acid (PHB) production in cyanobacteria have not been clearly documented. In the present study, three PHB producers belonging to cyanobacteria were identified as Oscillatoria salina, Anabaena cylindrica and Nostoc linckia, based on their morphological features and microscopic observations. Their growth and PHB production after 7, 14 and 21 days in BG11 medium were determined. The highest dry weight for the isolates was observed at stationary phase (14 days) and PHB accumulation (%, w/w of dry cells) increased with increasing dry weight up to 14 days, then a decline was observed after 21 days. At the stationary phase, cells of O. salina, A. cylindrica and N. linckia accumulated PHB up to 13.62, 11.88 and 10.03% (w/w of dry cells), respectively. The pH values between 8 and 9 were preferred for PHB accumulation. O. salina, A. cylindrica and N. linckia accumulated the highest PHB 17.31, 15.22 and 14.95%, respectively at pH 8. Nitrogen and phosphorus starvation were found stimulatory for PHB accumulation and he highest PHB production was recorded for O. salina, 20.41 and 26.32%, respectively after 14 days of incubation. Electron microscopic analyses of O. salina cells showed the bioplastic accumulation in granule-like structures which was extracted and studied using IRFT analysis. In conclusion, cyanobacteria are capable of synthesizing high poly--hydroxybutyrate (PHB) under stress.

SUMMARYThis paper evaluates 30-year (2013–2042) projections of the selected climatic parameters in cotton/wheat agro-climatic zone of Pakistan. A statistical bias correction procedure was adopted to eliminate the systematic errors in output of three selected general circulation models (GCM) under A2 emission scenario. A transfer function was developed between the GCM outputs and the observed time series of the climatic parameters (base period: 1980–2004) and applied to GCM future projections. The predictions detected seasonal shifts in rainfall and increasing temperature trend which in combination can affect the crop water requirements (CWR) at different phonological stages of the two major crops (i.e. wheat and cotton). CROPWAT model is used to optimize the shifts in sowing dates as a climate change adaptation option. The results depict that with reference to the existing sowing patterns, early sowing of wheat and late sowing of cotton will favour decreased CWR of these crops.

Due to aridity, scarcity and unsustainably of natural water resources many developing countries tend to utilize wastewater for crop production. The use of treated wastewater in irrigation has many advantages and disadvantages to soil, crop and environment. The objective of the study was to investigate the effect of irrigation with wastewater on soil physical and hydraulic properties of soil, as well as the effect on yield, yield components and irrigation water use efficiency (IWUE) of vegetable crop grown under surface and subsurface drip irrigation systems. Field experiments were carried out over two consecutive seasons (2011 and 2012) at an agricultural field site in Saudi Arabia. A strip plot design (split block) was constructed to maintain six wastewater qualities. Crop water requirement was calculated by Penman Monteith equation for dry land condition. Physical and hydraulic properties of soil were analyzed at pre-season and post-season to quantify the impact of wastewater treatment. Results were statistically analyzed by analysis of variance and mean separation by LSD test. Post-season analysis indicates that the second layer of soil profile was affected. The saturated hydraulic conductivity decreased by 43%, α value increased by 6%, and n value decreased by 2%. Accordingly simulation results a reduction of cumulative flow through soil profile was observed. On the other hand, the response ofvegetable crop to wastewater qualities, irrigation systems and growing seasons was different. The fruit yield and IWUE under subsurface irrigation system were significant as compared to surface irrigation system using two seasons. However, the local groundwater (LGW) practice produced highest yield and maximum IWUE; followed by qualities containing less percentage of wastewater. The statistical approach was successful in the analysis of designed experiment.

Increasing lack of potable water in arid countries leads to the use of treated wastewater for crop production. However, the use of inappropriate irrigation practices could result in a serious contamination risk to plants, soils, and groundwater with sewage water. This research was initiated in view to the increasing danger of vegetable crops and groundwater contamination with pathogenic bacteria due to wastewater land application. The research was designed to study: (1) the effect of treated wastewater irrigation on the yield and microbial contamination of the radish plant under field conditions; (2) contamination of the agricultural soil profile with fecal coliform bacteria. Effluent from a domestic wastewater treatment plant (100%) in Jeddah city, Saudi Arabia, was diluted to 80% and 40% with the groundwater of the experimental site constituting three different water qualities plus groundwater as control. Radish plant was grown in two consecutive seasons under two drip irrigation systems and four irrigation water qualities. Upon harvesting, plant weight per ha, total bacterial, fecal coliform, fecal streptococci were detected per 100g of dry matter and compared with the control. The soil profile was also sampled at an equal distance of 3cm from soil surface for fecal coliform detection. The results indicated that the yield increased significantly under the subsurface irrigation system and the control water quality compared to surface irrigation system and other water qualities. There was a considerable drop in the count of all bacteria species under the subsurface irrigation system compared to surface irrigation. The bacterial count/g of the plant shoot system increased as the percentage of wastewater in the irrigation water increased. Most of the fecal coliform bacteria were deposited in the first few centimeters below the column inlet and the profile exponentially decreased with increasing depth.

Thermal properties of fossil fuel are the key fundamental characteristics, which can distinguish any compound as a potential fuel. The performance of diesel fuel blend along with stability and solubility parameter designs are evaluated. The results from the experimental study indicate that the increase in hydrogen peroxide (H2O2) amount enhances the cetane number of diesel fuel blend significantly. However, the calorific value decreases as compared to pure diesel fuel. All values performed well according to the ASTM D-975 diesel testing method. The thermodynamics of the prepared fuel blends also revealed that substantial solubility and diesel/H2O2 blend stability are provided even at lower temperatures. Such blends can be used as a feasible replacement of pure diesel fuel. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

This study reports the removal of nickel(II) and copper(II) ions (Ni2+ and Cu2+) from aqueous solution using pure and chemically pretreated biomass from Arachis hypogea (peanut shells), Prunus amygdalus (almond shells), Arundo donax (giant cane) and two clay materials, clay G and clay B. These materials are indigenous, easily available, surpulus by-products for biosorption studies. Batch experiments were carried out to determine the effect of various adsorbent factors such as initial pH, temperature, particle size and contact time on the adsorption process. For adsorption application, up to 99% removal of both metal ions was achieved by biomass and clay materials. Furthermore, chemically modified adsorbents significantly increased the uptake capacity of biomass, suggesting that the affinity between metal and sorbent can be increased after pretreatment. Equilibrium isotherms were analyzed using Langmuir and Freundlich isotherm models, and both models fitted to explain the adsorption behavior of metal ions ...

The wastewater containing heavy metals, produced at various stages of operation in textile, printing, plastic, and paper-making industries, pose major hazards to the environment and the public health. Therefore, it is necessary that the pollutants should be treated before discharge by using highly efficient adsorbents. Zeolite is a potential material and can conveniently be processed as adsorbents for the removal of environmental pollutants. A wide range of commercial zeolite has been marketed but due to high cost it is of limited use. The present research offers a green approach for the application of zeolite synthesized by using marble powder waste as a precursor. The significance rests on the conversion of waste into a useful adsorbent marble zeolite (MZ). Zeolite is an environmental friendly, novel, and cost-effective adsorbent. In the current study, remediation of heavy metals in industrial wastewater is done using zeolite. The marble waste contains metals like Zn, Ni, Pb, Cr, Cd, and Cu in i...

Seawater desalination is one of the most important means of securing water for domestic needs in arid geographical regions such as Saudi Arabia. Water production of Jeddah desalination plant is critical in meeting the city’s increasing water demands. The plant uses reverse osmosis technique with a production system consisting mainly of a permeate tank and production pumps. Failure or shutdown of any operating pump causes serious issues in demand and loss of production. The objective of this study is to develop a cost-effective operation policy that ensures the plant’s continuous production rate throughout the failure of any production pump. Mathematical optimization technique is used to explore possible and optimal solutions for the plant’s operation policies. The case was formulated as mixed-integer programming to minimize an objective function. POM-QM for Windows package was used to solve the problem using branch and bound method. This mathematical programming proved to be a powerful technique n...

Jeddah city depends entirely on desalinated seawater for its fresh water supply which exceeds 1.2 Mm3/d. Around 40% of the water used in the urban area infiltrates into the underlying shallow groundwater from cesspits and wastewater networks. This process resulted in groundwater table rise in many parts of the city and the occurrence of a polluted brackish groundwater (BGW) which is a mix of fresh water, domestic sewage, seawater intrusion, and urban runoff. Membrane technologies such as hybrid membrane systems and membrane bioreactors coupled with reverse osmosis membrane systems have been well established as cost-effective, feasible, and efficient solutions for desalination of contaminated water sources. This study emphasizes on the potential of BGW in Jeddah urban water cycle as one of its main components and the key principles of integrated urban water cycle management applied to Jeddah context. The study assessed the favorable conditions, driving factors, and the feasibility of integrating BG...

Ammonia-oxidizing bacteria (AOB) play a key role in the production of nitrate-N (NO3−-N) in terrestrial ecosystems. A study was planned with the aim of assessing the effect of azo dyes released by textile and dyestuff industries on the NH4+-N oxidation process in soil. The data was analyzed statistically using a two factorial completely randomized design (CRD). The results of the study demonstrated that higher doses of reactive black 5 (RB5) significantly suppressed the NH4+-N oxidation process throughout incubation. Average percent inhibition rates (%) were in the following order: coarse > fine > medium soil. Overall average percent inhibition rates (%) of nitrification in soils exposed to 30 mg-N kg−1 soil ammonium sulfate [(NH4)2SO4] were 46–53% higher than those from 90 mg-N kg−1 soil. This may be attributed to (NH4)2SO4 that acts as a substrate for the proliferation of AOB. NO3−-N concentration was strongly negatively correlated (r = −0.86) with various amounts of RB5, whereas a strong positive response was observed for the inhibition rate (r = 0.92). A considerable decrease in AOB population (up to 92.58%) was detected for >200 mg kg−1 soil plus N fertilizer, which differed with soil type. This study could be helpful to investigate the effect of contaminants on biochemical processes occurring in soil. Furthermore, the inhibitory effect of azo dye on the NH4+-N oxidation process suggests that critical concentrations of organic dyes may be used as an inhibitor to release NO3−-N in soil at a slow rate in order to further reduce NO3−-N contamination in terrestrial and aquatic ecosystems and to allow less frequent application of ammonium fertilizer in soil as well.

In recent years, considerable interest has arisen with regard to the fate and transport of radionuclides such as iodine-131 (131I), cesium-134 (134Cs), and cesium-137 (137Cs) in aquatic environments. 137Cs is an important indicator of radioactive pollution in aquatic environments. The transport and fate of anthropogenic 137Cs is related to the chemical properties of ionic Cs (Cs+), which generally dictates a high degree of mobility and bioavailability of this radionuclide. The transport of 137Cs and its partitioning between abiotic and biotic components of aquatic ecosystems are complex processes that are considerably affected by a number of factors such as mineralogical composition of suspended and bottom sediments and the characteristic geochemistry of water. These factors influence sorption and desorption kinetics of 137Cs and the transport of particulate 137Cs. Nevertheless, substantial evidence suggests that direct biological 137Cs accumulation from the aquatic environment occurs readily in micro-org...

Radionuclide contamination in terrestrial ecosystems has reached a dangerous level. The major artificial radionuclide present in the environment is (137)Cs, which is released as a result of weapon production related to atomic projects, accidental explosions of nuclear power plants and other sources, such as reactors, evaporation ponds, liquid storage tanks, and burial grounds. The release of potentially hazardous radionuclides (radiocesium) in recent years has provided the opportunity to conduct multidisciplinary studies on their fate and transport. Radiocesium's high fission yield and ease of detection made it a prime candidate for early radio-ecological investigations. The facility setting provides a diverse background for the improved understanding of various factors that contribute toward the fate and transfer of radionuclides in the terrestrial ecosystem. In this review, we summarize the significant environmental radiocesium transfer factors to determine the damaging effects of radiocesium on terrestrial ecosystem. It has been found that (137)Cs can trace the transport of other radionuclides that have a high affinity for binding to soil particles (silts and clays). Possible remedial methods are also discussed for contaminated terrestrial systems. This review will serve as a guideline for future studies of the fate and transport of (137)Cs in terrestrial environments in the wake of the Fukushima Nuclear Power Plant disaster in 2011.

The study of biofilms has skyrocketed in recent years due to increased awareness of the pervasiveness and impact of biofilms. It costs the USA literally billions of dollars every year in energy losses, equipment damage, product contamination and medical infections. But biofilms also offer huge potential for cleaning up hazardous waste sites, filtering municipal and industrial water and wastewater, and forming biobarriers to protect soil and groundwater from contamination. The complexity of biofilm activity and behavior requires research contributions from many disciplines such as biochemistry, engineering, mathematics and microbiology. The aim of this review is to provide a comprehensive analysis of emerging novel antimicrobial techniques, including those using myriad organic and inorganic products as well as genetic engineering techniques, the use of coordination complex molecules, composite materials and antimicrobial peptides and the use of lasers as such or their modified use in combination treatments. This review also addresses advanced and recent modifications, including methodological changes, and biocide efficacy enhancing strategies. This review will provide future planners of biofilm control technologies with a broad understanding and perspective on the use of biocides in the field of green developments for a sustainable future.

Due to permanent dry conditions in arid land basins, channels experience a great quantity of water loss during the runoff process. The objective of this study is to quantify and delineate the spatial variability of channel losses over the contributing area of the upstream side of Wadi Al-Lith, in the western region of Saudi Arabia, by using Muskingum–Cunge flow routing method. HEC-HMS model was used here to simulate rainfall-runoff relationship, to route flood hydrograph, and to determine losses in the channel network of the basin. The required geomorphological parameters such as channel’s geometry, roughness coefficient, and slopes obtained from GIS and field measurements. The model was calibrated and validated on real rainfall-runoff events and the optimized parameters were generalized. Results showed that both calibrated and validated hydrographs are in good agreement with observed hydrographs. Channel constituted the highest losses from the total rainfall and that these losses increased as the basin area increased and the slope decreased. The maximum percentage loss was 47.3% and the minimum percentage loss was 2.1%. Although these losses are from surface water, at the same time these losses are considered as gains to the subsurface storage. Therefore, such losses and gains should be considered in the water resources planning and management formulation.

Pathogenic bacteria, that enter surface water bodies and groundwater systems through unmanaged wastewater land application, pose a great risk to human health. In this study, six soil column experiments were conducted to simulate the vulnerability of agricultural and urban field soils for fecal bacteria transport and retention under saturated and unsaturated flow conditions. HYDRUS-1D kinetic attachment and kinetic attachment-detachment models were used to simulate the breakthrough curves of the experimental data by fitting model parameters. Results indicated significant differences in the retention and drainage of bacteria between saturated and unsaturated flow condition in the two studied soils. Flow under unsaturated condition retained more bacteria than the saturated flow case. The high bacteria retention in the urban soil compared to agricultural soil is ascribed not only to the dynamic attachment and sorption mechanisms but also to the greater surface area of fine particles and low flow rate. All models simulated experimental data satisfactorily under saturated flow conditions; however, under variably saturated flow, the peak concentrations were overestimated by the attachment-detachment model and underestimated by the attachment model with blocking. The good match between observed data and simulated concentrations by the attachment model which was supported by the Akaike information criterion (AIC) for model selection indicates that the first-order attachment coefficient was sufficient to represent the quantitative and temporal distribution of bacteria in the soil column. On the other hand, the total mass balance of the drained and retained bacteria in all transport experiments was in the range of values commonly found in the literature. Regardless of flow conditions and soil texture, most of the bacteria were retained in the top 12 cm of the soil column. The approaches and the models used in this study have proven to be a good tool for simulating fecal bacteria transport under a variety of initial and boundary flow conditions, hence providing a better understanding of the transport mechanism of bacteria as well as soil removal efficiency.

Wastewater irrigated fields can cause potential contamination with heavy metals to soil and groundwater, thus pose a threat to human beings . The current study was designed to investigate the potential human health risks associated with the consumption of okra vegetable crop contaminated with toxic heavy metals. The crop was grown on a soil irrigated with treated wastewater in the western region of Saudi Arabia during 2010 and 2011. The monitored heavy metals included Cd, Cr, Cu, Pb and Zn for their bioaccumulation factors to provide baseline data regarding environmental safety and the suitability of sewage irrigation in the future. The pollution load index (PLI), enrichment factor (EF) and contamination factor (CF) of these metals were calculated. The pollution load index of the studied soils indicated their level of metal contamination. The concentrations of Ni, Pb, Cd and Cr in the edible portions were above the safe limit in 90%, 28%, 83% and 63% of the samples, respectively. The heavy metals in the edible portions were as follows: Cr > Zn > Ni > Cd > Mn > Pb > Cu > Fe. The Health Risk Index (HRI) was >1 indicating a potential health risk. The EF values designated an enhanced bio-contamination compared to other reports from Saudi Arabia and other countries around the world. The results indicated a potential pathway of human exposure to slow poisoning by heavy metals due to the indirect utilization of vegetables grown on heavy metal-contaminated soil that was irrigated by contaminated water sources. The okra tested was not safe for human use, especially for direct consumption by human beings. The irrigation source was identified as the source of the soil pollution in this study.

Use of artificial neural networks (ANNs) is becoming increasingly common in the analysis of groundwater hydrology and water resources problems. In this research, an ANN was developed and used to estimate aquifer parameter values, namely transmissivity and storage coefficient, from pumping test data for a large diameter well. The ANN was trained to map time–drawdown and well diameter data (input vector) to its corresponding transmissivity and storage coefficient values (output vector). Based upon a pre-specified range of aquifer parameters, the input vectors were generated from the analytical solution of Papadopulos and Copper for large diameter well in a homogeneous, isotropic, non-leaky confined aquifer. The ANN was trained with a fixed number of drawdown data points corresponding to a varying pre-specified range of aquifer parameters and time-series values. Once the network is trained to an acceptable level of accuracy, it produces an output of aquifer parameter values for any input vector. The results obtained with the ANN are in good agreement with published values. A significant advantage of the ANN approach is that it overcomes the problem of determining the storage coefficient, which when determined by traditional type curve matching method is of questionable reliability.

This study was conducted to investigate the chemical speciation of dissolved and particulate elements (lead, zinc, copper, chromium, arsenic, and tin) in the mining wastewater of a former tin-mining catchment. The speciation patterns of dissolved elements were estimated by an adsorptive stripping voltammeter (ASV), while particulate elements were analyzed by using a newly developed sequential-extraction leaching procedure. The procedure has been operationally defined among five host fractions, namely exchangeable, carbonate, reducible, organic bound, and residual fractions. A total of six elements (lead, zinc, copper, chromium, arsenic, and tin) were analyzed in thirty samples at ten locations (P1-P10), with three samples taken from each of the ten locations, to get the average value from the former tin-mining catchment. The results showed that the heavy metal pollutions in locations P4 and P8 were more severe than in other sampling sites, especially tin and lead pollution. In the water samples from locations P4 and P8, both the total contents and the most dangerous non-residual fractions of tin and lead were extremely high. More than 90% of the total concentrations of arsenic and chromium existed in the residual fraction. Concentrations of copper and zinc mainly occurred in the residual fraction (more than 60%), while lead and tin presented mostly in the non-residual fractions in surface water. For all of the six dissolved elements, the less-labile species formed the predominant fraction in their speciation patterns. The speciation patterns of particulate elements showed that most of the concentrations of zinc, copper, chromium, and arsenic were found in the reducible fraction; whereas lead and tin were mainly associated with the organic fraction.

Radionuclide contamination in terrestrial ecosystems has reached a dangerous level. The major artificial radionuclide present in the environment is (137)Cs, which is released as a result of weapon production related to atomic projects, accidental explosions of nuclear power plants and other sources, such as reactors, evaporation ponds, liquid storage tanks, and burial grounds. The release of potentially hazardous radionuclides (radiocesium) in recent years has provided the opportunity to conduct multidisciplinary studies on their fate and transport. Radiocesium's high fission yield and ease of detection made it a prime candidate for early radio-ecological investigations. The facility setting provides a diverse background for the improved understanding of various factors that contribute toward the fate and transfer of radionuclides in the terrestrial ecosystem. In this review, we summarize the significant environmental radiocesium transfer factors to determine the damaging effects of radiocesium on terrestrial ecosystem. It has been found that (137)Cs can trace the transport of other radionuclides that have a high affinity for binding to soil particles (silts and clays). Possible remedial methods are also discussed for contaminated terrestrial systems. This review will serve as a guideline for future studies of the fate and transport of (137)Cs in terrestrial environments in the wake of the Fukushima Nuclear Power Plant disaster in 2011.

The toxicity of organophosphate insecticides for nontarget organism has been the subject of extensive research for sustainable agriculture. Pakistan has banned the use of methyl/ethyl parathions, but they are still illegally used. The present study is an attempt to estimate the residual concentration and to suggest remedial solution of adsorption by different types of soils collected and characterized for physicochemical parameters. Sorption of pesticides in soil or other porous media is an important process regulating pesticide transport and degradation. The percentage removal of methyl parathion and ethyl parathion was determined through UV-Visible spectrophotometer at 276 nm and 277 nm, respectively. The results indicate that agricultural soil as compared to barren soil is more efficient adsorbent for both insecticides, at optimum batch condition of pH 7. The equilibrium between adsorbate and adsorbent was attained in 12 hours. Methyl parathion is removed more efficiently (by seven orders of magnitude) than ethyl parathion. It may be attributed to more available binding sites and less steric hindrance of methyl parathion. Adsorption kinetics indicates that a good correlation exists between distribution coefficient (Kd) and soil organic carbon. A general increase in Kd is noted with increase in induced concentration due to the formation of bound or aged residue.

The study of biofilms has skyrocketed in recent years due to increased awareness of the pervasiveness and impact of biofilms. It costs the USA literally billions of dollars every year in energy losses, equipment damage, product contamination and medical infections. But biofilms also offer huge potential for cleaning up hazardous waste sites, filtering municipal and industrial water and wastewater, and forming biobarriers to protect soil and groundwater from contamination. The complexity of biofilm activity and behavior requires research contributions from many disciplines such as biochemistry, engineering, mathematics and microbiology. The aim of this review is to provide a comprehensive analysis of emerging novel antimicrobial techniques, including those using myriad organic and inorganic products as well as genetic engineering techniques, the use of coordination complex molecules, composite materials and antimicrobial peptides and the use of lasers as such or their modified use in combination treatments. This review also addresses advanced and recent modifications, including methodological changes, and biocide efficacy enhancing strategies. This review will provide future planners of biofilm control technologies with a broad understanding and perspective on the use of biocides in the field of green developments for a sustainable future.

Radionuclide contamination in terrestrial ecosystems has reached a dangerous level. The major artificial radionuclide present in the environment is 137Cs, which is released as a result of weapon production related to atomic projects, accidental explosions of nuclear power plants and other sources, such as reactors, evaporation ponds, liquid storage tanks, and burial grounds. The release of potentially hazardous radionuclides (radiocesium) in recent years has provided the opportunity to conduct multidisciplinary studies on their fate and transport. Radiocesium’s high fission yield and ease of detection made it a prime candidate for early radio-ecological investigations. The facility setting provides a diverse background for the improved understanding of various factors that contribute toward the fate and transfer of radionuclides in the terrestrial ecosystem. In this review, we summarize the significant environmental radiocesium transfer factors to determine the damaging effects of radiocesium on terrestrial ecosystem. It has been found that 137Cs can trace the transport of other radionuclides that have a high affinity for binding to soil particles (silts and clays). Possible remedial methods are also discussed for contaminated terrestrial systems. This review will serve as a guideline for future studies of the fate and transport of 137Cs in terrestrial environments in the wake of the Fukushima Nuclear Power Plant disaster in 2011.

Abstract Characterization of heterogeneity at the field scale generally requires detailed aquifer properties such as transmissivity and hydraulic head. An accurate delineation of these properties is expensive and time consuming, and for many if not most groundwater systems, is not practical. As an alternative approach, stochastic representation of random fields is used and presented in this paper. Specifically, an iterative stochastic conditional simulation approach was applied to a hypothetical and highly heterogeneous pre-designed aquifer system. The approach is similar to the classical co-kriging technique; it uses a linear estimator that depends on the covariance functions of transmissivity (T), and hydraulic head (h), as well as their cross-covariances. A linearized flow equation along with a conditional random field generator constitutes the iterative process of the conditional simulation. One hundred equally likely realizations of transmissivity fields with pre-specified geostatistical par...

Several issues related to the probabilistic and hydraulic structure of the geomorphologic instantaneous unit hydrograph (GIUH) are addressed. These issues are: (1) accuracy of the geomorphologic expressions of the probabilities of surface runoff movement in a watershed, (2) identifying, for a given storm, a representative time-average velocity for surface runoff, (3) estimation of this velocity for the ungauged watersheds and effect of velocity estimation errors on the GIUH predictability, and (4) suitability of incorporating a linear expression for infiltration in the GIUH as well as the estimation problem of the infiltration coefficient and its effect on the reliability of predicted hydrographs. These issues are analyzed through application of the GIUH for two gauged watersheds in the southwestern region of Saudi Arabia. Twelve storm events are used in the analysis and the results are presented.