Search

Renewable water resources are limited in arid and semiarid countries. The lack of surface waters and groundwater recharge makes the use of non-renewable groundwater resources inevitable. In many countries in the MENA Region (Middle East/North Africa), non-renewable groundwater is the major resource for both municipal and agricultural water demand. Integrated Management of non-renewable groundwater resources has to cope with the fact, that the resources are dwindling, and sustainability in terms of a balanced water budget cannot be achieved. Hence, focus must be set on the economic and social welfare resulting from the use of these limited resources. Long-term water management plans are needed to overcome economic inefficiencies within the water sector and to ensure a safe water supply for the present and future generations. In the MENA region, the technical development and rapid population growth lead to an overexploitation of the non-renewable groundwater resources, mainly by agricultural users, resulting in water quality deterioration, local water shortage, and establishment of expensive long-distance water supply systems. Here, todays major challenges of Integrated Water Management are: (1) to mitigate the user conflict between municipal and agricultural users, (2) to protect the dwindling resources, and (3) to implement an economic view on the water sector. Facing these challenges ensures the best use of the non-renewable resources, turning them into economic and social welfare for the population. [ABSTRACT FROM AUTHOR]

Abstract: Removal of 12 organic contaminants from water using a microporous polypropylene hollow fiber membrane (HFM) module was studied under low strip gas flow to water flow ratios (≤5:1). Removal efficiencies were found to be strongly dependent on the Henry''s law constants indicating a substantial mass transfer resistance on the gas side. Vacuum can be either used to increase removal efficiencies, or to decrease the amount of strip gas that has to be treated without sacrificing efficiency. [Copyright &y& Elsevier]

Abstract: Applying a new hybrid numerical and analytical approach in the finite element simulator RockFlow/GeoSys for hydraulic flow and mass transport, the efficiency of the removal of organic contaminants from water using a microporous polypropylene hollow fiber membrane module (HFM) was accurately modeled for a large range of operating conditions. The modeling results were validated against 177 experimental measurements under a wide range of operating conditions for 12 organic compounds with different diffusion coefficients and a wide variety of Henry''s law constants, from Naphthalene at circa 0.017 to 1,1-dichloroethene with circa 1.19. The hybrid numerical analytical approach enables prediction of the removal efficiencies within a few minutes, whereas a pure numerical approach would require several hours to days due to numerical stability controls. The input parameters for the model are defined by the geometry of the HFM and the operating conditions, no empirical formulations are applied. This model allows the investigation of the main factors controlling the removal characteristics, e.g., the dependency on Henry''s law coefficient, gas side diffusional resistance, and aqueous diffusion limitation, and also enables the efficient design of further organic removal systems based on the HFM technology. [Copyright &y& Elsevier]

Shwan sub-Basin is one of the substantial groundwater sources in northern Iraq. Along with an increase in population, agricultural and industrial activities synced with the change in climate conditions, all could have a negative impact on the hydrochemistry of groundwater. Therefore, it becomes crucial to investigate the different processes that could affect hydrochemistry and water quality. Thirty-two groundwater samples were collected from wells distributed in the study area, and one surface water sample from Lesser Zab River, all water samples were gathered during two seasons. Hydrogeochemical model was performed on physiochemical analysis results by using PHREEQC software to understand the geochemical reactions occurring in groundwater. The results of the Saturated Index showed supersaturated values for calcite, aragonite and dolomite in groundwater samples during the first season in a percent of 84%. While the second season samples were supersaturated in percent of 40.6%, 37.5% and 46.8% for aragonite, calcite and dolomite minerals respectively. The Saturated Index shows supersaturated values of quartz mineral in most groundwater samples, which are sourced from the abundance of silicate minerals that are primarily included within the ambient rock materials of the tertiary and quaternary clastic aquifer system in the study region. The saturated index showed undersaturated values with most minerals of feldspar, halide and sulfate. However, these minerals were in a dissolution state, releasing significant amounts of Ca 2+ , Na + , Mg 2+ , HCO 3 - , Cl ⁻ and SO 4 2- ions into the solution. Most of the groundwater samples were classified as earth-alkaline water with an increased portion of alkali with prevailing bicarbonate for two seasons, except the groundwater sample W2 was classified as earth-alkaline water with an increased portion of alkali with prevailing SO 4 2⁻ and Cl ⁻ . The water quality for human drinking was evaluated using the water quality index (WQI). The values of WQI were from 51.9 to 99.2 and from 53.9 to 88.5 for the first and the second seasons respectively. WQI revealed that most of the samples were classified as poor to very poor water quality, except the Lesser Zab River sample for the second season was good water quality and the sample W2 for the first season was unsuitable for drinking purposes., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Lake Urmia in north-western Iran was once one of the world's largest hyper-saline lakes and represented a unique ecosystem for a number of endangered species. The lake's shrinking over the past decades has attracted considerable attention and several studies have addressed its water balance. Yet, evaporation of shallow groundwater from the dried-up lake bed has not been fully quantified - despite the appreciable size of these areas (approx. 4000 km 2 in summer 2015). Here, we target this water cycle component by combining column experiments with upscaling and regionalisation techniques. In the experiments, we studied evaporation from two undisturbed soil cores from the exposed lake bed in a climate chamber, mimicking diurnal temperature and humidity variations in the three summer months of the study area. Despite the dropping water levels in the columns and the formation of salt crusts, evaporation rates remained remarkably constant (0.12 and 0.20 mm d -1 ). This suggests that the system is not driven by slow vapour diffusion, but controlled by capillary rise in the fine-grained sediments, ensuring steady water supply to the column surface. Thus, evaporation from the dried-up lake bed can be assumed to be largely independent from the unsaturated zone thickness (within the observed water level range) and evaporation rates can be simply upscaled and regionalised by considering the satellite-derived development of dried-up lake bed areas (1998-2020). In this time-period, estimated summer evaporation from the exposed lake bed reached maximum values of 0.04 and 0.07 km 3 (summer 2015). While these absolute numbers are significant (comparable to the catchment's annual urban drinking water consumption), they correspond to only 4 and 7 % of the evaporation from the open lake surface (1.06 km 3 )., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

In this study, we analyzed the concentration distributions of 20 polycyclic aromatic hydrocarbons (PAHs) in 41 water samples which were collected from the northern part of Taihu Lake during 4 field campaigns (201511, 201606, 201702 and 201709). The concentrations were determined with GC-MS, and their spatial and seasonal distribution characteristics were interpreted. The results show that 2-ring PAHs present considerably higher concentrations in warm seasons than cold seasons, but the concentrations of the other higher-ring PAHs are rather stable in warm and cold seasons. The distribution patterns of these PAHs might be mainly attributed to ambient temperature effects on the PAH solubility in the water body. Meanwhile, the spatial distributions of the PAH concentrations in cold seasons were rather various in the sampling area, while the distributions in the warm seasons were homogeneous. The different distributions could result from the water recharge from the Yangtze River during cold seasons, which diluted PAH concentrations in the northeastern part of the lake. Furthermore, via literature review on PAH concentrations in water body, PAHs are in a wide range of levels and their patterns are different among the studies, which should be more effected by local factors instead of general PAH properties. The results from this study also present special characteristics of PAHs in Taihu Lake, which exhibit more insight on PAHs existence in water bodies., (© 2022. The Author(s).)

Adsorption and bioremediation are effective processes for remediation of benzene, toluene, and ethylbenzene (BTE) through Permeable Reactive Barriers (PRBs). A few researches focus on adsorption of natural zeolite because of its hydrophilic property. On the other hand, PRBs need to be replaced by fresh materials after a while when all the possible absorption positions were filled up. We tried to find a way to increase the efficiency of PRB, elongation of its replacement period and of course decreasing the cost of remediation. Equipping of PRB with microbial degradation system was the idea. The present study describes the performances of natural Clinoptilolite-Heulandite Zeolite (CH-Z) and three new strains (safe and low-cost media) utilized in a PRB for removing BTE from contaminated shallow groundwater. First, batch tests were conducted to recognize the optimal removal conditions for utilization of C-HZ and strains to remediate BTE compounds. Then, an aerobic PRB system filled with a natural zeolite was designed and investigated in a continuous flow sand-tank model to assess the efficiency of combined PRBs (zeolite + biosparging), for BTE-contaminated groundwater. Batch experiments showed that the BTE removal of zeolite was 89%, as well as, a consortium of three bacterial strains, Variovorax sp. OT16, Pseudomonas balearica OT17, and Ornithinibacillus sp. OT18 efficiently removed the BTE mixture. The process of BTE removal in the PRB under continuous-flow condition was divided into three phases: Phase I, in which the barrier was made of the only zeolite, and in Phases II and III the reactor was fed by microorganisms. This experiment revealed that in Phases I, the concentrations of BTE decrease (92%) due to zeolite adsorption. In Phase II and III, the degradation process became the principal removal mechanism (68% and 81%, respectively). Consequently, this research showed high ability of C-HZ in the BTE treatment, and a combination of Natural Zeolite, with a biological degradation system (CH-Z -PRB) improves the efficiency of BTE remediation. However, the slow biodegradation rates and the continuous injection of BTE in the model confirmed that longer time was needed for the PRB to function optimally. Finally, the combined method of CH-Z- BIO PRB showed the great potential in the restriction of the BTE migration that can be used at the field-scale after up-scaling., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Increasing water salinity in coastal areas is a concern for the coastal environment. Increased salinity is affecting water quality, freshwater availability, and water-related ecosystems in the southwest coastal region of the Bengal Delta. The study used a synergies and robust approach to assess the possible factors for increasing water salinity in an embanked coastal island in the southwest Bengal Delta. The hydrochemical analysis revealed that surface and groundwater are enriching with Na + and Cl - concentration, also controlling by seawater through the ion exchange mechanism (Ca 2+ and Mg 2+ replacing by Na + , and Cl - ), mixing stage of water solution (freshwater-saltwater), and anthropogenic salt contamination by human activities (e.g., saltwater shrimp cultivation and excessive irrigation). Piper diagram showed that river water is occupying at the mixing stage of solution, where pond and groundwater are occupying at seawater (saline) zone. The water quality index showed that surface water is not fresh anymore and unsuitable for drinking purposes. The isotope analyses exposed the presence of strong precipitation variance in the study area. Cluster observation analysis showed a strong correlation between Na + , Cl - , and TDS (similarity is 97% to 99%). The remote sensing application illustrated that high salinity zones are in the northern part, and groundwater salinity is higher (7.5 to 8 ppt) in the northern part of polder 32. The salinity of both groundwater and surface water showed a positive correlation with land surface temperature and potential evapotranspiration. The study exposed four responding factors for increasing groundwater salinity in this region, which are - regional surface geological settings, hydrological settings, hydraulic head gradient, and human activities. A conceptual model illustrated the presence of lateral recharge of saltwater from the surrounding tidal rivers to the groundwater., Competing Interests: Declaration of competing interest This research conducted by field and laboratory-based water parameters analysis. The research ensures that there was no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The Hazaribagh industrial area in Dhaka city, the capital of Bangladesh, is considered one of the hotspots of chromium (Cr) pollution, due to excessive discharge of Cr contaminated waste over decades by approximately 150 tanneries. In 2000, elevated Cr concentrations were observed in the underlying Dupi Tila Aquifer (DTA), which is heavily deployed for drinking water supply of Dhaka city's population. In the following years, Cr concentrations in the DTA have dropped and apparently stayed low. In 2010, elevated Cr concentrations were found again in the DTA. This study aims to evaluate the status of the total Cr contamination in the surface waters, groundwater, and soils in the area, to clarify the temporal evolution of the total Cr contamination pattern in the DTA. For this, we collected water and soil samples in 2012, 2013, 2014, and 2019 for (hydro)chemical characterization and analyzed new groundwater level data on the development of the cone of depression below the city. Our study indicates that the temporal evolution of the total Cr contamination in the DTA is closely coupled to the groundwater dynamics. The rapid growth of the cone of depression due to excessive pumping resulted (i) in a disconnection of the groundwater table from the heavily contaminated Hazaribagh soils, and (ii) in an increased gradient between the contaminated surface waters and the groundwater, increasing infiltration into the groundwater. Finally, (iii) the further growth of the cone of depression resulted in an inflow of fresh groundwater from the west of Dhaka city, causing a dilution effect. Although in 2017 tanneries were moved out of the Hazaribagh area, the contaminated soils still pose a threat to groundwater quality when groundwater levels would recover., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The potential of biochar to enhance phytorestoration of hexavalent chromium [Cr(VI)]-contaminated soils was investigated. Rooted cuttings of Ficus elastica Roxb. Ex Hornem were transplanted to soil treated with 0 or 25 mg kg -1 Cr(VI), ‒Cr and +Cr designations respectively, and amended with cattle manure-derived biochar at 0, 10 and 50 g kg -1 . Plants were grown for 180 d in a temperature-controlled greenhouse. In the ‒Cr treatment, biochar addition enhanced plant growth without affecting plant water status, leaf nutrient levels, photochemical efficiency, or hormone levels. In the absence of biochar, Ficus growth in the +Cr treatment was stunted, exhibiting decreased leaf and root relative water content and photochemical efficiency. Adding biochar to +Cr soil resulted in decreased Cr uptake into plant tissues and alleviated the toxic effects of soil Cr(VI) on plant growth and physiology, including decreased leaf lipid peroxidation. High-resolution electron microscopy and spectroscopy elucidated the biochar role in decreasing Cr mobility, bioavailability, and phytotoxicity. Spectroscopic evidence is suggestive that biochar mediated the reduction of Cr(VI) to Cr(III), which was subsequently incorporated into organomineral agglomerates formed at biochar surfaces. The dual function of biochar in improving F. elastica performance and detoxifying Cr(VI) demonstrates that biochar holds much potential for enhancing phytorestoration of Cr(VI)-contaminated soils., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Lake Urmia is one of the largest hypersaline lakes on earth with a unique biodiversity. Over the past two decades the lake water level declined dramatically, threatening the functionality of the lake's ecosystems. There is a controversial debate about the reasons for this decline, with either mismanagement of the water resources, or climatic changes assumed to be the main cause. In this study we quantified the water budget components of Lake Urmia and analyzed their temporal evolution and interplay over the last five decades. With this we can show that variations of Lake Urmia's water level during the analyzed period were mainly triggered by climatic changes. However, under the current climatic conditions agricultural water extraction volumes are significant compared to the remaining surface water inflow volumes. Changes in agricultural water withdrawal would have a significant impact on the lake volume and could either stabilize the lake, or lead to its complete collapse.

When biochar (BC) is applied to soil, one process that can alter its properties and contaminant sorption is the leaching of minerals and dissolved organic carbon (DOC). This study investigated changes in properties of three BCs (cattle manure, grain husk, and wood chips), due to leaching, and the subsequent impact on sorption of trichloroethylene (TCE) and tetrachloroethylene (PCE). The manure-derived BC released 27.4 mg g -1 DOC, which is over ten times more than that measured for the two plant-based BCs (2.5 and 1.5 mg g -1 DOC for grain husk and wood chips, respectively). In all leachates, potassium is the dominant cation, whereas chloride, sulfate, and phosphate are the main anions. In total, the manure-derived biochar released the highest sum of total ions (73.1 mg g -1 ), followed by BC produced from grain husk (15.5 mg g -1 ) and wood chips (1.2 mg g -1 ). Leaching increased external surface area, mesopore volume, and hydrophobicity of the manure-derived BC and decreased its polarity. This enhanced sorption via partitioning. In plant-based BCs, micropore volume and size distribution were altered, most likely through the un-blocking of pores, causing increased sorption via pore-filling for both TCE and PCE. The results indicate that, depending on feedstock material, BC leaching can alter the environmental fate of organic compounds.

In the present work, we analyzed the concentration patterns of 20 Polycyclic Aromatic Hydrocarbons (PAHs) in 25 surface sediments and 11 sediment cores from the northern part of Taihu Lake, China. Three of the cores were dated based on 137 Cs activity for the deposition age of the sediment. The spatial distributions of the PAH concentrations show that the inflow rivers into Zhushan Bay and Meiliang Bay were the main pathway for PAHs and sediment input to the northern part of the lake. This results in substantially higher PAH concentrations (up to 5000 ng/g) and sedimentation rates (higher than the average of 3-4 mm/a) in the area close to the river outlets. In addition, results also show that PAH concentrations in the sediments considerably increased from the early 1960s, but the decreasing concentrations in the upper layers of the sediment could be attributed to the introduction of measures on environmental improvement from ca. 2000. There were both anthropogenic and biogenic origins of perylene in the lake sediments, which were distinguished based on spatial distribution patterns and also the concentration proportions of perylene to the sum of the 20 PAHs. In the cores collected close to river outlets, the concentration proportions of perylene typically range from 0.02 to 0.18 and there are significant positive linear correlations between the concentration of perylene and three anthropogenic PAHs (Benzo[a]pyrene, Benzo[e]pyrene, Pyrene), suggesting that perylene was dominated by anthropogenic input. However, the cores collected further away from the river outlets show the concentration proportions between 0.13 and 0.96, and present significant negative correlations or no correlations between perylene and the three PAHs, suggesting that perylene was mainly formed by biogenic activities. Furthermore, the different perylene sources accompanied with the location distributions imply that anthropogenic activities could inhibit its biogenic formation., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The ability of a soil to sustain infiltration rates and to attenuate pollutants is critical for the design and operation of Managed Aquifer Recharge/Soil Aquifer Treatment and phyto-treatment schemes, also referred to as "Blue Infrastructures". We investigated the buffering capacity of a sediment sample and a peat soil sample for nutrients and selected pharmaceutical compounds and its evolution under continuous infiltration of secondary treated wastewater (TWW) in column experiments. Samples were obtained from two blue infrastructures, the Sant'Alessio Induced River Bank Filtration plant and the San Niccolò large-scale phyto-treatment plant in Italy, and were mainly different in their organic carbon contents (0.9 and 48%, respectively). In the column experiments, a constant infiltration rate of about 0.5 L/d was maintained for 6 months. After 4 months of operation, diclofenac and carbamazepine were spiked into the TWW to evaluate their fate. Water quality was monitored by periodic water sampling from the column inflow, at sampling ports along the column length, and at the outflow. Hydraulic conductivity (K) was also monitored. The hydraulic conductivity of the Sant'Alessio sediment decreased by a factor of 10 during the first 10 days of infiltration and then stabilized, while for the San Niccolò K (initially lower) remained constant for 50 days until it decreased following a change of the redox condition in the column. The different redox conditions, due to the two different soils tested, influenced also the concentration and mobility of PO 4 3- , Fe, Mn, and NPOC, and the speciation of the redox sensitive elements (nitrogen and sulfur). NOPC and phosphate were enriched during the filtration through San Niccolò peat soil (from 2 to 4 times, respectively), while they were buffered by the Sant'Alessio sediment (from 0.2 to 0.4 times, respectively). Diclofenac removal (69% and below 20% for San Niccolò and Sant'Alessio, respectively) was related to sorption and degradation processes and it was lower than the removal of carbamazepine in both soils (76 and 35%). The buffer capacity differences between the two soils were higher for diclofenac (62%) than carbamazepine (35%). Nevertheless, since no apparent degradation of carbamazepine was detected in both soils, its persistence in the soil may have a larger impact in case of desorption, posing contamination risk to groundwater. The results highlight the importance of the soils or sediments to be used as medium in such nature-based solutions for their operations. They also offer an approach to, e.g., tailor man-made soil layers in infiltration basins. We strongly suggest that soil characteristics and test duration are carefully considered in designing these infrastructures, when nature-based processes are the choice for dealing with reuse of treated wastewater management issues.

Infiltration of treated wastewater (TWW) to recharge depleted aquifers, often referred to as managed aquifer recharge, is a solution to replenish groundwater resources in regions facing water scarcity. We present a mass balance approach to infer the amounts of five pharmaceuticals (carbamazepine, diclofenac, fenoprofen, gemfibrozil, and naproxen) degraded in column experiments based on concentrations of pharmaceuticals in the aqueous and solid (sorbed) phases. Column experiments were conducted under three different conditions: continuous infiltration, wetting and drying cycles, and wetting and drying cycles with elevated concentrations of antibiotics (which may reduce microbially aided degradation of other compounds). A mass balance comparing pharmaceutical mass in the water phase over the 16-month duration of the experiments to mass sorbed to the soil was used to infer the mass of pharmaceuticals degraded. Results show sorption as the main attenuation mechanism for carbamazepine. About half of the mass of diclofenac was degraded with wetting and drying cycles, but no significant degradation was found for continuous infiltration, while 32% of infiltrated mass sorbed. Fenoprofen was degraded in the shallow and aerobic part of the soil, but degradation appeared to cease beyond 27 cm depth. Gemfibrozil attenuated through a combination of degradation and sorption, with slight increases in attenuation with depth from both mechanisms. Naproxen degraded progressively with depth, resulting in attenuation of >90% of the mass. In the column with elevated concentrations of antibiotics, the antibiotics attenuated to about 50% or less of inflow concentrations by 27 cm depth and within this zone, less degradation of the other compounds was observed., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Biochar is increasingly deemed a potential sorbent for contaminants in soil and water remediation. We tested three biochars from different feedstocks (cattle manure, grain husk, and wood chips) produced at relatively low pyrolysis temperature (450 °C), for their sorption behavior towards trichloroethylene (TCE) and tetrachloroethylene (PCE) in single- and bi-solute systems. In single-solute experiments, all biochars show stronger sorption for TCE (about 50% based on solubility-normalized Freundlich coefficients). The lower sorption of PCE is attributed to steric effects, e.g. size exclusion in small micropores and specific interactions. Plant-derived, carbon-rich biochars with high specific surface area and microporosity predominantly sorb via pore-filling, as also observed in activated carbon. Biochar produced from manure, with higher ash content and polarity, and smaller total pore volume (PV tot ), shows significant contribution of partitioning. These findings also apply to bi-solute systems. TCE and PCE show different competition behavior depending on biochar properties. Plant-based biochars are pore-filling-dominated and show strong competition. However, competition behavior in microporous biochars depends on the concentration range. Manure biochar with high polarity and low PV tot shows significant partitioning and therefore less competition. Compared to the plant-based chars competition in manure biochar is not concentration-dependent. These results indicate that biochars with a large fraction of non-carbonized phase facilitate non-competitive sorption and might be a valuable sorbent in mixed contaminant systems., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Adding biochar to Zn-contaminated soil can immobilize excess Zn and promote plant biomass growth. This was seen previously over the course of a 180-day planted pot trial involving two types of biochar (cattle manure, CM, and grain husk, GH) in a Zn-contaminated soil. Both biochars alleviated Zn-induced phytotoxicity to Ficus by immobilizing Zn and reducing its uptake by the plant, but to different extents. The aim of the current study was to delve into the in-soil mechanisms involved in biochar-mediated Zn immobilization. Biochar particles were excavated from the pot soils. Fresh and aged biochar particles were examined by high-resolution scanning electron microscope (SEM) coupled with energy dispersive X-ray spectroscopy (EDS), field-emission electron probe micro-analyzer (EPMA), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). The physical and chemical properties of the biochars had changed over the 180 days. SEM-EDS and EPMA indicated that organo-mineral micro-agglomerates had formed on biochar surfaces and in pores. Some of the Zn immobilized by the biochars was bound in the organo-mineral complexes of these agglomerates. XPS and FTIR showed that the complexes had a high concentration of oxygenated functional groups which facilitated Zn binding and encapsulation. The micro-agglomerates were similar in structure and composition to those observed on biochars having resided for much longer times in soils, or having been subjected to accelerated aging. Overall, Zn immobilization by the CM biochar was greater than by the GH biochar, due to its higher alkalinity, higher concentration of available negatively charged groups, and greater accretion of organo-mineral layers. These findings are suggestive that biochar-assisted phytorestoration of heavy metal-contaminated soils can be optimized through selection of biochar having such traits. It is hypothesized that metals may be continually taken up in such micro-agglomerates, since they continue to form over the lifetime of the biochar in the soil., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The Kirkuk region in northern Iraq hosts some of the largest oil fields in the Middle East. Several anticline structures enabled vertical migration and entrapment of the oil. Frequently, complex fracture systems and faults cut across the Eocene and middle Oligocene reservoirs and the cap rock, the Fatha Formation of Miocene age. Seepage of crude oil and oil field brines are therefore a common observation in the anticline axes and contamination of shallow groundwater resources is a major concern. In this study, 65 water samples were collected in the Kirkuk region to analyze and distinguish mixing processes between shallow groundwater resources, uprising oil field brines, and dissolution of gypsum and halite from the Fatha Formation. Hydrochemical analyses of the water samples included general hydrochemistry, stable water isotopes, as well as strontium concentrations and for 22 of the samples strontium isotopes ((87)Sr/(86)Sr). Strontium concentrations increased close to the anticline axes with highest concentrations in the oil field brines (300mg/l). Strontium isotopes proved to be a valuable tool to distinguish mixing processes as isotope signatures of the oil field brines and of waters from the Fatha Formation are significantly different. It could be shown, that mixing of shallow groundwater with oil field brines is occurring close to the major fault zones in the anticlines but high concentrations of strontium in the water samples are mainly due to dissolution from the Fatha Formation., (Copyright © 2016 Elsevier B.V. All rights reserved.)