The Impact of Inoculation of Two Strains of Rhizobacteria on Radionuclide Transfer in Sesbania Grandiflora.

Transfer factors of some naturally-occurring and artificial radionuclides from an agricultural soil to rhizobacteria-treated Sesbania grandiflora, a small leguminous tree, were studied. Two plant growth promoting rhizobacteria (PGPR) strains (SCR17 and PCE2) were used to carry out an agricultural experiment in pots in semi-arid region (Syria). The results showed the bacterial strain (SCR17) increased the transfer and accumulation of 238U and 40K in Sesbania grandiflora, while both bacterial strains showed no effect on the accumulation of 234Th, 226Ra, 210Po and 210Pb in the treated plants. The transfer factor of 137Cs from soil to rhizobacteria-treated Sesbania grandiflora was negligible. The values of the transfer factors of 234Th, 226Ra, 210Po and 40K were found to be within the global values, while the values of the transfer factors of 238U and 210Pb were found to be relatively higher. This study highlights the importance of using Phytoremediation by PGPR strains for radionuclides-contaminated soils. Therefore, this method is a promising technique for the restoration and rehabilitation of contaminated sites with radionuclides, as it is low cost, easy to apply, and environmentally friendly.

Geochemistry of uranium and thorium in phosphate deposits at the Syrian coastal area (Al-Haffah and Al-Qaradaha) and their environmental impacts.

The aim of this research was to study the geochemistry of uranium and thorium in phosphate deposits in the upper Cretaceous phosphate deposits in the Syrian coastal area. The study covered three sites, namely Ain Al-Tenah, Ain Laylon, and Al-Mhalbeh. Petrographical study showed that phosphate deposits are of nodular type with micrit to microspaite cement, containing siliceous bone residues, and green grains of glauconite, which are increasing in abundance and volume in the south toward Al-Mhalbeh, reflecting the formation of phosphate in a shallow marine environment. In addition, uranium concentration varied between 3 and 112 ppm in Ain Laylon, 4.2-17 ppm in Ain Al-Tenah and 5-61 ppm in Al-Mhalbeh. Thorium concentration varied between 0.2 and 7.5 ppm in Ain Laylon, 0.3-1.4 ppm in Ain Al-Tenah and 0.3-4.4 ppm in Al-Mhalbeh. The average Th/U ratio in the collected samples was within the range 0.04-0.08 except for five samples which exceeded the value 0.1. Moreover, the 226Ra/238U ratios are lower than unity in all samples, while the 210Pb/238U ratios ranged between 0.4 and 1.2 and the 210Pb/226Ra ratios were found to be higher than unity. On the other hand, the impact of leaching and mobility of uranium and thorium from deposits to the surrounding agriculture fields in the area has been studied using the Radium Equivalent Activity Index (Raeq). The equivalent radium activity was 102 Bq kg-1 in Ain Al-Tenah, 403 Bq kg-1 in Ain Laylon, 407 Bq kg-1 in Al-Mhalbeh and 749 Bq kg-1 in agricultural soil samples. However, the data reported in this study can be considered as a baseline data for the phosphate deposits at the coastal area.

Comparison of 238U, 210Po and 210Pb Speciation in Six Different Types of Soils.

Speciation of 238U, 210Po and 210Pb in six different types of Syrian soil (Entisols, Inceptisol, Aridisol, Mollisols, Vertisols and Rock outcrops) was studied using a four-step sequential extraction procedure. The binding nature of 238U, 210Po and 210Pb was correlated with soil properties including soil particles, pH, EC, OM, sand, silt and clay. The results showed that the exchangeable and carbonate fractions of 238U did not exceed 10%. In addition, the 238U, 210Po and 210Pb fractions bonded to organic matter increased as the soil clay content decreased. The highest 210Po fraction was found to be bonded to soil Fe/Al/Mn-oxides for Entisols soils (56%) and silica for Aridisol soils (53%). Soil clay content showed a linear correlation with 210Po concentrations in soils ranging from 0.34 to 0.91. The results are considered useful in assessing the risks resulting from soils contaminated by naturally occurring radioactive material from the phosphate and oil industry.

A Study on Sorption of (226)Ra on Different Clay Matrices.

The sorption of radium 226 ((226)Ra) on different clay materials (bentonite, illite and a mixture of bentonite-illite) was studied. Clay materials are used in the construction of disposal pits for technically enhanced naturally occurring radioactive materials (TENORM) wastes (i.e., contaminated soil and sludge) generated by the oil and gas industry operations. Experimental conditions (pH, clay materials quantity, and activity concentrations of (226)Ra) were changed in order to determine the optimal state for adsorption of (226)Ra. The results showed that the concentration of adsorbed (226)Ra on clay materials increased with time to reach an equilibrium state after approximately 5 h. More than 95 % of the radium was adsorbed. The mixture of bentonite-illite (1/9) exhibited the greatest adsorption of radium under all experimental conditions.

Neutron activation analysis of thermal power plant ash and surrounding area soils.

Elemental concentrations of As, Cd, Co, Cr, Fe, Hg, Mo, Ni, Se, and Zn have been determined in fly and bottom ash collected from Syrian power plants fired by heavy oil and natural gas using instrumental neutron activation analysis. The results showed that all elements were more concentrated in fly ash than in the fly ash; there was a clear increasing trend of the elemental concentrations in the fly ash along the flue gas pathway. The annual emission of elements was estimated. Elemental concentrations were higher inside the campus area than in surrounding areas, and the lowest values were found in natural-gas-fired power plant. In addition, the levels have decreased as the distance from power plant campus increases. However, the levels in the surrounding villages were within the Syrian standard for agriculture soil.

Monitoring of ¹³7Cs fallout in Syrian environment.

This paper presents measurements of cesium 137 ((137)Cs) in the Syrian environment during the period between 2006 and 2010. More than 1,000 samples of soil, water, plants and aquatic life were collected from different locations. The measurements were realized using gamma spectroscopy, and the results showed that radioactivity concentrations were low overall. Concentrations ranged from below detection limits to several tens Bq kg(-1) (dry matter) or 9.8 mBq L(-1) (water), which were well below maximum allowable levels in food or drinking water as established according to Syrian national standards or the WHO/FAO Codex guidelines. However, high (137)Cs activity levels were observed in soil samples collected at a high elevation (Kadmous highs), where a mean concentration of 1,900 Bq kg(-1) was obtained.

Treatment of produced water using Mn oxide nanoparticales loaded on walnut shells.

Sorption of 226Ra from produced water with oil production on manganese oxide nanoparticles loaded on walnut shell media was investigated using batch-type technique. The results showed that 226Ra is effectively adsorbed onto the adsorbent with equilibrium time of approximately 30 min. Removal efficiency of 226Ra from produced water depends mainly on the adsorbent dose and concentration of associated ions; removal efficiency decreased when their concentrations increase. The maximum adsorption capacity is reached 58 Bq g-1. The adsorbent is effective and suitable for removing 226Ra ions from the produced water under the studied conditions in this work.

Comparison of three analytical techniques for determination of Th and U in environmental samples.

Alpha-particle spectrometry, gamma spectrometry and neutron activation analysis techniques for determination of Th and U in environmental samples have been compared. The analytical parameters studied include detection limit, accuracy, repeatability, reproducibility and surrogate recovery. The results show that neutron activation analysis technique has the best accuracy among the studied techniques; the other two techniques were assessed relative to it. The percentage difference between the three techniques results is about [-20, 20]. In addition, U and Th concentrations are generally overestimated by gamma spectrometry and alpha-particle spectrometry in all cases except Th concentration in the former technique, which is underestimated.

Assessment of natural radionuclide transfer factors and partition coefficients in some Syrian soils.

Transfer factors of radium 226(226Ra), lead 210(210Pb), polonium 210 (210Po), uranium 238 (238U) and thorium 234(234Th) from five different agricultural soils in Syria to coriander, parsley and mint were investigated in a pot culture experiment. Geometric means of transfer factors (TF)were226Ra (0.13),210Pb(0.03), 210Po (0.02) and 238U (1.76) were within worldwide values, while TF values for 234Th (1.35) were higher than those recorded globally. The available transfer factor (ATF) values ranged between 0.03 and 1.45, 0.33 and 3.2, 0.10 and 3.36, 1.30 and 16.2 and 1.0 and 6.95 for226Ra,210Pb,210Po, 238U and 234Th, respectively. However, it is worth mentioning that the data from pot experiments may not represent field conditions. Liquid/solid partition coefficients (Kd)of 226Ra, U, 210Pb and 210Po for55 soils representing the dominant types of soils in Syria were also determined. Geometric means of Kd values ranged from 280 to1200, 750 to1600, 350to 4800 and 100-120 L kg-1 for 226Ra, 238U, 210Pb and 210Po, respectively at pH = 4.0, and from 200 to 6700, 670 to 2400, 150 to 2100 and 100 to 160Lkg-1at pH = 5.5, and from 370 to 790, 130 to 550, 60 to 330 and370 to 920Lkg-1at pH = 7.0. The effects of soil mineral content, CEC, ECE, pH and soluble ions on the Kd values were investigated. In general, there were logarithmic relationships between the activity concentrations in soil and the Kd values (R2 ranged from 0.59 to 1.00 at pH 4.0). There were no relationships between the Kd values and soil pH.

Effect of forkhead box O1 (FOXO1) on beta cell development in the human fetal pancreas.

AIMS/HYPOTHESIS: Recent studies have demonstrated that in adult murine beta cells the forkhead box O1 (FOXO1) transcription factor regulates proliferation and stress resistance. However, the role of FOXO1 during pancreatic development remains largely unknown. The present study aimed to characterise the expression of the FOXO1 transcription factor in the early to mid-gestation human fetal pancreas and to understand its role in islet cell development. METHODS: Human (8-21 week fetal age) pancreases were examined using immunohistological, quantitative RT-PCR and western blotting. Isolated human (18-21 week) fetal islet epithelial cell clusters were treated with insulin or glucose, or transfected with FOXO1 small interfering RNA (siRNA). RESULTS: Nuclear and cytoplasmic FOXO1 were widely produced during human fetal endocrine pancreatic development, co-localising in cells with the transcription factors pancreatic and duodenal homeobox 1 (PDX-1) and neurogenin 3 (NGN3) as well as cytokeratin 19 (CK19), insulin and glucagon. Treatment with exogenous insulin (50 nmol/l) induced the nuclear exclusion of FOXO1 in both cytokeratin 19 (CK19)(+) (p < 0.01) and insulin(+) cells (p < 0.05) in parallel with increased phospho-Akt (p < 0.05) production. siRNA knockdown of FOXO1 significantly increased the number of NGN3(+) (p < 0.01) and NK6 homeobox 1 (NKX6-1)(+) (p < 0.05) cells in parallel with increases in insulin gene expression (p < 0.03) and C-peptide(+) cells (p < 0.05) and reduced levels of hairy and enhancer of split 1 (HES1) (p < 0.01). CONCLUSIONS/INTERPRETATION: Our results indicate that FOXO1 may negatively regulate beta cell differentiation in the human fetal pancreas by controlling critical transcription factors, including NGN3 and NKX6-1. These data suggest that the manipulation of FOXO1 levels may be a useful tool for improving cell-based strategies for the treatment of diabetes.

Sorption of 226Ra from waste effluents using Syrian bentonite.

In view of environmental concern, sorption of radium on natural bentonite mineral (Aleppo, Syria) was investigated using a batch-type method. Data were expressed in terms of distribution coefficients. An attempt to increase the selectivity of bentonite for radium was made by preparing M-derivatives. Loss of mineral crystallinity in acidic media and the formation of a new phase, such as BaCO3, in Ba-derivative were evidenced by XRD characterizations. Of the cationic forms, Na-bentonite showed the highest affinity. Mechanisms of radium uptake were studied using M-derivatives and simulated radium solutions. The obtained results indicated that surface sorption/surface ion exchange were the predominant processes. The distinct sorption behaviour observed with the Ba-form was, possibly, a reflection of radium coprecipitation with barium carbonate. The competing order of macro components, likely present in waste streams, was investigated by studying different concentrations of the corresponding salt media. Sodium was found to be the weakest inhibitor. The performance of natural bentonite and the most selective forms, i.e. Ba- and Na-derivatives, to sorb radium from actual oil co-produced waters, collected form Der Ezzor Petroleum Company (DEZPC), was studied. This showed the influential effect ofpH compared with other parameters.

An in vitro nutritive evaluation and rumen fermentation kinetics of Sesbania aculeate as affected by harvest time and cutting regimen.

The nutritive value of Sesbania aculeate harvested after 60 and 120 days of planting and subjected to two cutting regimen (15 or 30 cm length) was evaluated by determination of the crude protein (CP), crude fibre (CF), buffer soluble nitrogen (BS-N), buffer soluble non-protein nitrogen (BS-NPN) and cell wall constituents (neutral-detergent fibre; NDF, acid-detergent fibre; ADF and lignin). In vitro digestible organic matter (IVDOM), metabolizable energy (ME), microbial nitrogen (MN) and biomass (MBM) production were also estimated in the experimental plant samples after their incubation with rumen fluid for 96 h in the absence or presence of polyethylene glycol (PEG, 6000) at a ratio of 2:1 PEG:substrate. Fermentation characteristics (initial gas production; a, gas production during incubation; b, potential gas production; a+b, fractional rate of gas production; c) were assessed using an in vitro incubation technique with rumen fluid. There was a significant (P < 0.05) effect of harvest time on all studied nutritive parameters and fermentation characteristics. The early harvest plant samples (after 60 days of planting) gave significantly higher values of IVOMD, ME, CP, BS-N, BS-NPN, MN, MBM and fractional rate of gas production and lower values of CF and cell wall constituents than the late harvest. Crude protein, BS-N, BS-NBN, IVOMD and ME were negatively correlated with CF and cell wall constituents. Metabolisable energy and IVOMD were positively correlated with CP, BS-N and BS-NPN. Cutting treatments significantly affected the CP, CF, BS-N, BS-NPN, NDF, ADF, IVDOM, ME, potential gas production and b values. There was no significant (P > 0.05) effect of added PEG on IVDOM, ME, MN, MBM, fermentation characteristics and gas production over 96 h. The greatest proportion of gas production occurred between 6 and 24 h of incubation. The fractional rate of gas production from 100 mg substrate was higher (0.046 mL/h) for the plant samples harvested at early stage and cut at 30 cm length than harvested at late stage (0.018 mL/h). C values were negatively correlated with lignin concentrations. The amount of MN and MBM produced from 100 mg substrate amounted to 1.29 mg and 14.95 mg at early maturity stage and 0.68 mg and 7.89 mg at late stage, respectively. Microbial nitrogen and MBM production were negatively correlated with CF, cell wall constituents and gas production but positively correlated with CP, BS-N and BS-NPN.

Radon gas distribution in natural gas processing facilities and workplace air environment.

Evaluation was made of the distribution of radon gas and radiation exposure rates in the four main natural gas treatment facilities in Syria. The results showed that radiation exposure rates at contact of all equipment were within the natural levels (0.09-0.1 microSvh(-1)) except for the reflex pumps where a dose rate value of 3 microSvh(-1) was recorded. Radon concentrations in Syrian natural gas varied between 15.4 Bq m(-3) and 1141 Bq m(-3); natural gas associated with oil production was found to contain higher concentrations than the non-associated natural gas. In addition, radon concentrations were higher in the central processing facilities than the wellheads; these high levels are due to pressurizing and concentrating processes that enhance radon gas and its decay products. Moreover, the lowest 222Rn concentration was in the natural gas fraction used for producing sulfur; a value of 80 Bq m(-3) was observed. On the other hand, maximum radon gas and its decay product concentrations in workplace air environments were found to be relatively high in the gas analysis laboratories; a value of 458 Bq m(-3) was observed. However, all reported levels in the workplaces in the four main stations were below the action level set by IAEA for chronic exposure situations involving radon, which is 1000 Bq m(-3).

Transfer of (40)K, (238)U, (210)Pb, and (210)Po from soil to plant in various locations in south of Syria.

Transfer factors of (40)K, (238)U, (210)Pb, and (210)Po from soil to some agriculture crops in various locations in south of Syria (Dara'a and Assuwaydaa districts) have been determined. Soil and vegetable crops (green pepper, cucumber, tomato, and eggplant), legumes crops (lentil, chickpea, and broad bean), fruit trees (apple, grape, and olives) and cereals (barley and wheat) were collected and analyzed for (238)U, (210)Pb, and (210)Po. The results have shown that higher transfer factors (calculated as Bqkg(-1) dry wt. plant material per Bqkg(-1) dry wt. soil) for (210)Po, (210)Pb and (238)U were observed in vegetable leaves than fruits and cereals leaves; the highest values of transfer factor (TF) for (238)U were found to be 0.1 for straw of chickpea. Transfer factors for (210)Po varied between 2.8x10(-2) and 2 in fruits of eggplant and grain of barley, respectively. In addition, several parameters affecting transfer factors of the radionuclides were evaluated. The results can be considered as base values for TF of natural radionuclides in the region.

Microbial load, acidity, lipid oxidation and volatile basic nitrogen of irradiated fish and meat-bone meals.

Experiments were carried out to study the effect of different doses of gamma irradiation (0, 5, 10, 15 and 20 kilo gray; kGy) on some nutritive components and chemical aspects pertaining to quality of fish meal and meat-bone meal. The radiation doses required to reduce the total microbial load and Salmonella sp. one log cycle (D(10)) in fish meal and meat-bone meal were determined. Results indicated that gamma irradiation of fish meal and meat-bone meal with 5-20 kGy doses had no effects on the total acidity values but increased the values of lipid oxidation and total volatile basic nitrogen. D(10) of total microbial load and Salmonella sp. were 833 and 313 Gy for fish meal and 526 Gy and 278 Gy for meat-bone meal, respectively. It can be concluded that radiation processing could be employed in the recycling of fish and meat-bone meals by using them as feedstuffs in poultry diets with no fear of losing their nutritive components.

Impact of phosphate industry on the environment: a case study.

This paper presents results obtained from studying the impact of the Syrian phosphate industry on the environment. This work is based on evaluating naturally occurring radionuclide concentrations in the surrounding environment at the locations of this industry, viz. mines, phosphate fertilizers factory and phosphate export platforms. Air particulates, soil, water (river, lake and sea water), biota and plant samples were collected and analyzed. Natural radionuclides ((226)Ra, (nat)U, (210)Po, (210)Pb) were determined by means of low background gamma spectrometry and alpha spectrometry. The results showed that the distribution and enhancement of natural radionuclides in the surrounding environment in these three locations are mainly due to fallout of phosphate dust generated during loading and processing of phosphate ore. The extent of contamination was related to climate conditions. Radon gas and its daughters generated from phosphate ores were found to be the main source of enhanced concentrations of (210)Po and (210)Pb in soil and leafy plants. These results can be considered as baseline data and can be used to prove the effectiveness of any future pollution controls adopted.

Spatial and monthly variations of radium isotopes in produced water during oil production.

Spatial and monthly variations of radium isotope concentrations in produced water have been evaluated during oil production. Samples of produced water were collected and analyzed on a monthly basis over a period of 5 months, the samples being derived from 11 main oil production wells at three Syrian oilfields. The highest average 226Ra, 228Ra and 224Ra concentrations in these samples of water were found to be 41, 37.5 and 1.1 Bql(-1), respectively. The data obtained for 226Ra, 228Ra and the 228Ra/226Ra activity ratio were evaluated statistically and displayed using the Box Plot method; clear variations can be observed from one field to another, indicating differences in the geological formation of the reservoir. The 228Ra/226Ra activity ratio variations reflect the variability of the Th/U mass ratio of the geological formation, suggesting two different source rock types. The calculated mean Th/U mass ratio for these two possible types of source rock were 2.4 and 5.78. In addition, the 228Ra/226Ra mean activity ratio was also used to estimate the age of some deposited scales in tubulars; the results were compared with the 224Ra/228Ra activity ratio dating method. Monthly variations of 226Ra and 228Ra activity concentrations and the 228Ra/226Ra activity ratio in produced water were also observed, the major causes for these variations being related to the type of injection water and interwell reactions. Possible relationships between 226Ra and 228Ra activity concentrations, the 228Ra/226Ra activity ratio and physical and chemical properties of produced water were statistically evaluated; no linear correlations were found.

Vertical distribution and inventories of 137Cs in the Syrian soils of the eastern Mediterranean region.

Vertical distribution and inventories of (137)Cs have been determined using radiocesium distributions in presumably undistributed soil profiles, collected from 36 sites distributed all over Syria (eastern Mediterranean region). Vertical distributions of (137)Cs in the collected profiles were found to be strongly correlated with soil type and five groups were identified. Based on these profiles, total (137)Cs inventory (bomb test and Chernobyl) varied between 320 Bq m(-2) and 9,647 Bq m(-2). Geographical mapping of (137)Cs inventories showed that the highest values were found in the coastal, middle and north-east regions of Syria indicating that Chernobyl atmospheric contribution to the total (137)Cs deposition in the region is predominant. In contrast, the lowest values were found in the south-east region (Syrian Badia), where a relatively uniform distribution was observed, which may only be attributed to the past global nuclear bomb test. The measured inventories were also compared with a mathematical model for estimating bomb derived (137)Cs reference inventories.

Speciation of 210Po and 210Pb in air particulates determined by sequential extraction.

Speciation of (210)Po and (210)Pb in air particulates of two Syrian phosphate sites with different climate conditions has been studied. The sites are the mines and Tartous port at the Mediterranean Sea. Air filters were collected during September 2000 until February 2002 and extracted chemically using different selective fluids in an attempt to identify the different forms of these two radionuclides. The results have shown that the inorganic and insoluble (210)Po and (210)Pb (attached to silica and soluble in mineral acids) portion was found to be high in both sites and reached a maximum value of 94% and 77% in the mine site and Tartous port site, respectively. In addition, only 24% of (210)Pb in air particulates was found to be associated with organic materials probably produced from the incomplete burning of fuel vehicle and similar activities. Moreover, the (210)Po/(210)Pb activity ratio in air particulates was higher than that in all samples at both sites and varied between 3.85 in November 2000 at Tartous port site and 20 in April 2001 at the mine area. These activity ratios were also higher than the natural levels. The (210)Po/(210)Pb activity ratio was also determined in each portion resulting from the selective extraction and found to be higher than that in most samples. The sources of (210)Po excess in these portions are discussed. Soil suspension, which is common in the dry climate dominant in the area, sea water spray and heating of phosphate ores were considered; polonium is more volatile than the lead compounds at even moderate temperature. Furthermore, variations in the chemical forms of (210)Po and (210)Pb during the year were also investigated. However, the results of this study can also be utilized for dose assessment to phosphate industry workers.

Dissolution of [²²6Ra]BaSO4 and partial separation of ²²6Ra from radium/barium sulfate: A new treatment method for NORM waste from petroleum industry.

Complete dissolution of [(226)Ra]BaSO4 precipitate was successfully performed using NaNO2 as a reducing agent in acidic solution at room temperature. Results showed a significant effect of acid and NaNO2 concentrations and temperature on the dissolution efficiency. The method was successfully used for separation of radium from NORM scale samples from the petroleum industry; sufficient volume reduction of NORM waste was achieved. The obtained (226)Ra solution was purified using two separation methods. The dissolution method can be of great interest in the development of radiochemical analysis of radium isotopes.