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Fish constitutes an essential source of high-quality protein and is, at the same time, the source of exposure to many hazardous contaminants, namely mercury and methyl mercury (MeHg). This study aims at assessing the risk that MeHg poses to the health of adult Qatari residents through fish consumption. Data on fish consumption were collected using a self-administered online survey composed of three sections that collected information about the fish-eating patterns of the participants. The fish species that were reported to be consumed by ≥ 3% of the respondents were sampled and analyzed for their total mercury (T-Hg) content levels. MeHg concentrations were derived from T-Hg content levels using a scenario-based approach. Disaggregated fish consumption and contamination data were combined using the deterministic approach to estimate MeHg intakes. The average, 75th, and 95th percentiles of the MeHg intake estimates were determined and compared to the tolerable weekly intake (TWI) set by the European Food Safety Agency (EFSA) (1.3 μg·kg−1·w−1). All fish samples contained T-Hg at levels ˂ 0.3–0.5 µg/g with a mean value of 0.077 µg/g. The study population had an average fish consumption of 736.0 g/week. The average estimated weekly intakes of MeHg exceeded TWI for some fish consumers including females of childbearing age and those following a high-protein diet. Our study highlights the need to establish regulatory guidelines and dietary advice based on risk/benefit ratio. [ABSTRACT FROM AUTHOR]

In this paper, novel composite materials from modified roasted date pits using ferrocyanides were developed and investigated for the recovery of lithium ions (Li+) from seawater reverse osmosis (RO) brine. Two composite materials were prepared from roasted date pits (RDP) as supporting material, namely potassium copper hexacyanoferrate-date pits composite (RDP-FC-Cu), and potassium nickel hexacyanoferrate-date pits composite (RDP-FC-Ni). The physiochemical characterization of the RO brine revealed that it contained a variety of metals and salts such as strontium, zinc, lithium, and sodium chlorides. RDP-FC-Cu and RDP-FC-Ni exhibited enhanced chemical and physical characteristics than RDP. The optimum pH, which attained the highest adsorption removal (%) for all adsorbents, was at pH 6. In addition, the highest adsorption capacities for the adsorbents were observed at the initial lithium concentration of 100 mg/L. The BET surface area analysis confirmed the increase in the total surface area of the prepared composites from 2.518 m2/g for RDP to 4.758 m2/g for RDP-FC-Cu and 5.262 m2/g for RDP-FC-Ni. A strong sharp infrared peak appeared for the RDP-FC-Cu and RDP-FC-Ni at 2078 cm−1. This peak corresponds to the C≡N bond, which indicates the presence of potassium hexacyanoferrate, K4[Fe(CN)6]. The adsorption removal of lithium at a variety of pH ranges was the highest for RDP-FC-Cu followed by RDP-FC-Ni and RDP. The continuous increase in the adsorption capacity for lithium with increasing initial lithium concentrations was also observed. This could be mainly attributed to enhance and increased lithium mass transfer onto the available adsorption active sites on the adsorbents' surface. The differences in the adsorption in terms of percent adsorption removal were clear and significant between the three adsorbents (P value < 0.05). All adsorbents in the study showed a high lithium desorption percentage as high as 99%. Both composites achieved full recoveries of lithium from the RO brine sample despite the presence of various other competing ions. [ABSTRACT FROM AUTHOR]

Background: The use of agricultural waste as a low-cost adsorbent for the removal of hazardous methylene blue (MB) from aqueous solution was investigated. In this research, the potentiality of using black nano olive stones (black NOS) and green nano olive stones (green NOS) for MB adsorption was conducted. Methods: Various remediation parameters such as initial MB concentration, pH, and temperature were investigated. Thermodynamic study was carried out to determine the homogeneity of the adsorbent and spontaneity of the adsorption process. Different physical and chemical characterizations were studied using scanning electron microscopy (SEM), Fourier transform infrared (FTIR), Brunauer-Emmett-Teller (BET) surface area, pore radius and pore volume. Results: It was found that NOS exhibits an acidic nature, however the highest MB removal efficiency was recorded at pH 10; reaching up to 71%. The negative value of the heat of the adsorption process (∆H °) indicated the reaction followed an exothermic pathway while the negative value of Gibbs adsorption (∆G °) further suggested its spontaneous nature. The results indicated that the Freundlich model described well the adsorption process with 99.5% correlation coefficient for green NOS. FTIR was used to analyze functional groups on the adsorbents' surfaces that could play vital roles in the remediation process. SEM analysis revealed that the adsorbents comprised of abundant spherical deep cavities and porous nature. Conclusion: The result obtained successfully demonstrated the potential of using black and green NOS as suitable adsorbents for the removal of MB from water. [ABSTRACT FROM AUTHOR]

Prosperity in Qatar and the consequent stresses on water resources resulted in a sustainable increase in the bottled drinking water market. Reports on health concerns and possible migration of chemicals from the plastic material into the water have driven the current investigation. This study aims to address the extent of antimony (Sb) leaching from polyethylene terephthalate (PET) water bottles subject to temperature variations (24-50 °C) due to Qatar's hot climate and improper storage conditions. A representative basket including 66 different imported and locally produced water bottles was considered. The concentrations of Sb in bottled water ranged from 0.168 to 2.263 μg/L at 24 °C and from 0.240 to 6.110 μg/L at 50 °C. Antimony concentrations in PET bottles at 24 °C was significantly lower than those at 50 °C ( p = 0.0142), indicating that the temperature was a principal factor affecting the release of Sb from the plastic into the water. Although the detected Sb amounts were below the guidelines endorsed by WHO and Qatar (standard 5 μg/L) at 24 °C, the concentration measured at 50 °C was higher than the recommended WHO values (6.11 μg/L). [ABSTRACT FROM AUTHOR]

Mangroves are unique ecosystems that dominate tropical and subtropical coastlines around the world. They provide shelter and nursery to wide variety of species such as fish and birds. Around 73 species of mangroves were recognized around the world. In Qatar, there is only one mangrove species Avicennia marina that is predominant along the northeastern coast. Assessing the health of these valuable ecosystems is vital for protection, management, and conservation of those resources. In this study, an integrated approach of chemical and remote sensing analysis was implemented to investigate the current status of the mangrove trees in Al-Khor, Qatar. Fifteen different A. marina trees from different locations in the mangrove forest were examined for their chlorophyll and nitrogen content levels. Soil analysis was also conducted to understand the effect of moisture on nitrogen availability. Results shows that currently, mangroves are in a good status in terms of nitrogen availability and chlorophyll levels which are related and both are key factors for photosynthesis. Remote sensing techniques were used for chlorophyll prediction. The results showed that these methods have the potential to be used for chlorophyll prediction and estimation. [ABSTRACT FROM AUTHOR]

The study aimed to examine the residues of organochlorines pesticides (OCPs) in vegetables and fruits in Qatar. A total of 127 samples was studied. Ninety percent of the imported samples recorded residues above the maximum residue levels (MRLs). The most frequently detected OCP in the samples was heptachlor (found in 75 samples). In the comparisons between the washed and unwashed samples, no significant differences were observed (P > 0.05). However, the effect of washing process with tap water depended on the type of vegetables and fruits. [ABSTRACT FROM AUTHOR]

Lead (Pb) is the second most toxic metal on Earth and is toxic to humans and other living things. In plants, Pb commonly inhibits growth when it is at a concentration in the soil of 30 mg/kg or more but several Pb tolerant plants have been reported. However, few studies have focused on plant response to Pb exposure, particularly at concentrations higher than 30 mg/kg. The assessment and evaluation of metal dose-dependent plant responses will assist in future phytoremediation studies. Therefore, this work documents the Pb concentration-dependent antioxidative response in Tetraena qataranse. Young seedlings were irrigated with 0, 25, 50, and 100 mg/L Pb every 48 h for seven weeks under greenhouse conditions. A phytotoxicity test showed that at the lowest treatment concentration, Pb stimulates growth. However, at 100 mg/L (1600 mg/kg Pb in the growth medium at harvest), the metal disrupted healthy growth in T. qataranse, particularly root development. Metal accumulation in the root was higher (up to 2784 mg/kg) than that of the shoot (1141.6 mg/kg). Activity assays of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), and glutathione reductase (GR) showed a progressive increase in enzymatic activities due to Pb treatment. Together, the results of this study suggest that T. qataranse is a Pb hyperaccumulator. Increased antioxidant enzyme activity was essential to maintaining cellular homeostasis and assisted in the arid plant's tolerance to Pb stress. [ABSTRACT FROM AUTHOR]

Measured viscosity and density data for ternary aqueous solutions of CaCl2 and KCl are presented at temperatures between 293 and 323 K with 5 K increment. A modified Jones–Dole was introduced by adding extra terms and proved to be suitable for modelling of the viscosity data. Goldsack and Franchetto, Hu and Exponential models are used to correlate the viscosity data, too. Al models are correlated as a function of temperature and concentration. All models had successfully predicted the viscosity with high precision reaching a maximum average absolute deviation (AAD) of less than 2.3%. The modified Jones–Dole showed the best results among other models. Viscosity of the ternary solution is higher than the viscosity of water by about 15% at low concentrations and reaches about 270% at the highest concentrations. The amount of CaCl2 has more significant effect on the ternary mixture viscosity compared to KCl. This has created difficulty in measuring the viscosity and consequently the challenge in finding the different models parameters. Ternary solution densities were successfully correlate with Kumar's model with AAD of less than 0.4%. Comparison of the ternary solution density and viscosity with the few available data literature showed a good agreement. [ABSTRACT FROM AUTHOR]

In the current study, the mechanistic understanding of the adsorption isotherm and thermodynamic aspects of cationic methylene blue (MB) dye adsorption onto cellulosic olive stones biomass from wastewater were investigated. The batch adsorption of MB onto the olive stones (black and green olive stones) was tested at a variety of pH, dye concentrations, temperatures, and biomass particle sizes. The adsorption thermodynamics such as Gibbs free energy, enthalpy, and entropy changes were also calculated. Moreover, the desorption studies of MB from the spent olive stones were studied to explore the re-usability of the biomasses. The results revealed that under the optimum pH of 10, the maximum MB uptake was achieved i.e. 80.2% for the green olive stones and 70.9% for the black olive stones. The green olive stones were found to be more efficient in remediating higher MB concentrations from water than the black olive stones. The highest MB removal of the green olive stones was achieved at 600 ppm of MB, while the highest MB removal of the black olive stones was observed at 50 ppm of MB. Furthermore, for almost all the concentrations studied (50–1000 ppm), the MB adsorption was the highest at the temperature of 45 °C (P value < 0.05). It was shown by the Fourier transform infrared that the electrostatic interaction and hydrogen bonding were proposed as dominant adsorption mechanisms at basic and acidic pH, respectively. While the hydrophobic-hydrophobic interaction was a dominant mechanism at neutral pH. The thermodynamic studies revealed that the adsorption process was endothermic, spontaneous, and favorable. Moreover, the real wastewater experiment and the desorption studies showed that the green and black olive stones were a cost-effective and promising adsorbents for MB remediation from wastewater on account of their high adsorption and desorption removal capacities. [ABSTRACT FROM AUTHOR]

This study attempted to use produced water (PW) to irrigate turfgrass species, Cynodon dactylon and Paspalum sp. Assessment on established grasses, heavy metal accumulation and germination tests for weeds and turf grass seeds were conducted to evaluate the impact of PW irrigation. C. dactylon depicted lower tolerance while Paspalum sp. showed better tolerance capacity towards PW. C. dactylon grown from seeds under greenhouse conditions were not able to tolerate more than 30% concentration of PW (4.5% salinity). In comparison to tap water irrigated turf grass, Paspalum sp. was found to accumulate higher concentrations of V and Pb in shoots and Cr, Ni and As in roots. The results of seed germination tests recommended that irrigation with PW is to be performed after turfgrass establishment. Germination tests also revealed that PW could encourage growth of the weed—Chloris virgata while it could discourage growth of Amaranthus viridis and Launaea mucronata. This study suggests that PW could be used for turfgrass as an alternative water resource but only after further research on the long-term scale. [ABSTRACT FROM AUTHOR]

The current work presented here focuses on the remediation of mercury from water using modified low-cost materials. Modified date pits, low cost, minimal pretreatment steps and locally abundant agricultural waste materials were effectively employed as an adsorbent for remediating Hg2+ from aqueous media. Physical and chemical modification were developed such as thermal roasting (RDP), sulfur (SMRDP) and silane (SIMRDP) based modifications. Results showed that maximum adsorption by RDP was at pH 6, AC and both modifications was at pH 4. Furthermore, RDP has exothermic adsorption mechanism while AC, SMRDP, and SIMRDP have endothermic. All adsorbents except SIMRDP have spontaneous adsorption process. SEM analysis showed that the surface morphology of RDP was not significantly affected by different treatments while surface of AC was affected. The investigation for good adsorbents for Hg2+ uptake from different anthropogenic sources has been carried out by many investigators worldwide towards having a safe environment. In the current study, the highest Hg2+ adsorption of SMRDP was relatively high compared to other known adsorbents. [ABSTRACT FROM AUTHOR]

The aims of this study were to investigate the vertical distributions of natural radionuclides 232Th, 226Ra and 40K as well as anthropogenic radionuclide 137Cs in soil samples and to analyze the correlation among the radioactivity of these radionuclides and the physiochemical characteristics of soil samples namely pH, grain size, carbonate content and organic matter. Risk assessment of the radiological hazard has also been estimated. Forty-four soil samples were collected from eleven locations in Qatar at four depth levels from 0 to 16 cm. The average concentrations of 232Th, 226Ra, 40K and 137Cs in the soil depth of 16 cm were 10, 17, 201 and 4 Bq/kg, respectively, which were within the reported world mean. The external absorbed gamma dose rate, the annual effective dose, the mean radium equivalent activity, the external hazard index and the lifetime cancer risk were 22 nGy/h, 0.027 mSv/y, 47 Bq/kg, 0.125 and 0.096 × 10−3, respectively. These values were far below the minimum recommended international values. The level of radioactivity concentrations in the soil was affected by the physiochemical characteristics of the soil. The positive correlation with highest R2 value was found among the radioactivity concentrations of 232Th and 40K and the soil clay content. Total organic carbon was also positively correlated for 226Ra and 137Cs activity concentrations, whereas, carbonate content was negatively correlated with the radioactivity concentrations of 232Th and 40K. As far as soil moisture content is concerned, the positive correlation with highest R2 value was obtained for 226Ra activity concentrations. [ABSTRACT FROM AUTHOR]

Background: This paper aims to investigate the occurrence and removal characteristics of phthalate esters from bottled drinking water using silver modified roasted date pits. Three adsorbents, namely roasted date pits (RODP), silver-modified roasted date pits (S-RODP), and activated carbon (AC) were used to investigate their adsorption characterizations in removing dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), di-2-ethylhexyl phthalate (DEHP), and di-n-octyl phthalate (DNOP) from the collected bottle water samples.The occurrences of the phthalate esters in the collected bottled water samples were carried out at different temperatures (30, 50, and 60 °C), and analyzed using gas chromatography-mass spectrometry analysis - selected ion monitoring. Batch adsorption isotherms were used to study and establish the efficiency of such adsorbents in removing phthalate esters, in which they describe the adsorbent-adsorbate interaction systems. Adsorption efficiency of the various adsorbents was investigated by using different adsorbent masses (0.05 g, 0.10 g, and 0.15 g) and temperature (30 °C, 50 °C, and 60 °C). Different physical and chemical characterizations were studied using scanning electron microscopy (SEM), Fourier transform infrared (FTIR), Brunauer-Emmett-Teller (BET) surface area, pore radius, and pore volume.The results indicated that the most abundant phthalate esters were DMP followed by DEP under 30 °C; however, DNOP was not detected in any of the tested water samples, except for one sample under 30 °C with a concentration of 0.031 μg/mL. The obtained results showed that phthalate esters leaching to the bottled drinking water were affected by storage temperature. The phthalate esters levels were increased with increasing the temperature to 60 °C. It was concluded that the ability of S-RODP for the adsorption of phthalate esters was better than the removal percentage obtained by AC and RODP. The removal percentage was increased from 90 to 99% by increasing the temperature from 30 to 50 °C and then decreased to 92.3% at 60 °C.RODP was successfully used as an effective adsorbent for phthalate esters removal from drinking water. However, S-RODP has the highest removal abilities than other adsorbents due to the newly formed functional groups on its surface.Methods: This paper aims to investigate the occurrence and removal characteristics of phthalate esters from bottled drinking water using silver modified roasted date pits. Three adsorbents, namely roasted date pits (RODP), silver-modified roasted date pits (S-RODP), and activated carbon (AC) were used to investigate their adsorption characterizations in removing dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), di-2-ethylhexyl phthalate (DEHP), and di-n-octyl phthalate (DNOP) from the collected bottle water samples.The occurrences of the phthalate esters in the collected bottled water samples were carried out at different temperatures (30, 50, and 60 °C), and analyzed using gas chromatography-mass spectrometry analysis - selected ion monitoring. Batch adsorption isotherms were used to study and establish the efficiency of such adsorbents in removing phthalate esters, in which they describe the adsorbent-adsorbate interaction systems. Adsorption efficiency of the various adsorbents was investigated by using different adsorbent masses (0.05 g, 0.10 g, and 0.15 g) and temperature (30 °C, 50 °C, and 60 °C). Different physical and chemical characterizations were studied using scanning electron microscopy (SEM), Fourier transform infrared (FTIR), Brunauer-Emmett-Teller (BET) surface area, pore radius, and pore volume.The results indicated that the most abundant phthalate esters were DMP followed by DEP under 30 °C; however, DNOP was not detected in any of the tested water samples, except for one sample under 30 °C with a concentration of 0.031 μg/mL. The obtained results showed that phthalate esters leaching to the bottled drinking water were affected by storage temperature. The phthalate esters levels were increased with increasing the temperature to 60 °C. It was concluded that the ability of S-RODP for the adsorption of phthalate esters was better than the removal percentage obtained by AC and RODP. The removal percentage was increased from 90 to 99% by increasing the temperature from 30 to 50 °C and then decreased to 92.3% at 60 °C.RODP was successfully used as an effective adsorbent for phthalate esters removal from drinking water. However, S-RODP has the highest removal abilities than other adsorbents due to the newly formed functional groups on its surface.Results: This paper aims to investigate the occurrence and removal characteristics of phthalate esters from bottled drinking water using silver modified roasted date pits. Three adsorbents, namely roasted date pits (RODP), silver-modified roasted date pits (S-RODP), and activated carbon (AC) were used to investigate their adsorption characterizations in removing dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), di-2-ethylhexyl phthalate (DEHP), and di-n-octyl phthalate (DNOP) from the collected bottle water samples.The occurrences of the phthalate esters in the collected bottled water samples were carried out at different temperatures (30, 50, and 60 °C), and analyzed using gas chromatography-mass spectrometry analysis - selected ion monitoring. Batch adsorption isotherms were used to study and establish the efficiency of such adsorbents in removing phthalate esters, in which they describe the adsorbent-adsorbate interaction systems. Adsorption efficiency of the various adsorbents was investigated by using different adsorbent masses (0.05 g, 0.10 g, and 0.15 g) and temperature (30 °C, 50 °C, and 60 °C). Different physical and chemical characterizations were studied using scanning electron microscopy (SEM), Fourier transform infrared (FTIR), Brunauer-Emmett-Teller (BET) surface area, pore radius, and pore volume.The results indicated that the most abundant phthalate esters were DMP followed by DEP under 30 °C; however, DNOP was not detected in any of the tested water samples, except for one sample under 30 °C with a concentration of 0.031 μg/mL. The obtained results showed that phthalate esters leaching to the bottled drinking water were affected by storage temperature. The phthalate esters levels were increased with increasing the temperature to 60 °C. It was concluded that the ability of S-RODP for the adsorption of phthalate esters was better than the removal percentage obtained by AC and RODP. The removal percentage was increased from 90 to 99% by increasing the temperature from 30 to 50 °C and then decreased to 92.3% at 60 °C.RODP was successfully used as an effective adsorbent for phthalate esters removal from drinking water. However, S-RODP has the highest removal abilities than other adsorbents due to the newly formed functional groups on its surface.Conclusion: This paper aims to investigate the occurrence and removal characteristics of phthalate esters from bottled drinking water using silver modified roasted date pits. Three adsorbents, namely roasted date pits (RODP), silver-modified roasted date pits (S-RODP), and activated carbon (AC) were used to investigate their adsorption characterizations in removing dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), di-2-ethylhexyl phthalate (DEHP), and di-n-octyl phthalate (DNOP) from the collected bottle water samples.The occurrences of the phthalate esters in the collected bottled water samples were carried out at different temperatures (30, 50, and 60 °C), and analyzed using gas chromatography-mass spectrometry analysis - selected ion monitoring. Batch adsorption isotherms were used to study and establish the efficiency of such adsorbents in removing phthalate esters, in which they describe the adsorbent-adsorbate interaction systems. Adsorption efficiency of the various adsorbents was investigated by using different adsorbent masses (0.05 g, 0.10 g, and 0.15 g) and temperature (30 °C, 50 °C, and 60 °C). Different physical and chemical characterizations were studied using scanning electron microscopy (SEM), Fourier transform infrared (FTIR), Brunauer-Emmett-Teller (BET) surface area, pore radius, and pore volume.The results indicated that the most abundant phthalate esters were DMP followed by DEP under 30 °C; however, DNOP was not detected in any of the tested water samples, except for one sample under 30 °C with a concentration of 0.031 μg/mL. The obtained results showed that phthalate esters leaching to the bottled drinking water were affected by storage temperature. The phthalate esters levels were increased with increasing the temperature to 60 °C. It was concluded that the ability of S-RODP for the adsorption of phthalate esters was better than the removal percentage obtained by AC and RODP. The removal percentage was increased from 90 to 99% by increasing the temperature from 30 to 50 °C and then decreased to 92.3% at 60 °C.RODP was successfully used as an effective adsorbent for phthalate esters removal from drinking water. However, S-RODP has the highest removal abilities than other adsorbents due to the newly formed functional groups on its surface. [ABSTRACT FROM AUTHOR]