Groundwater Purification in a Polymetallic Mining Area (SW Sinai,Egypt) Using Functionalized Magnetic Chitosan Particles

A magnetic glycine-grafted chitosan sorbent (Gly) was functionalized to produce a hydrazide derivative (HGly). The two sorbents were tested in batch mode for the sorption of a series of 10 metal ions present in the groundwater collected in three wells in the Wadi (valley) Nasib mining area (SW Sinai, Egypt). HGly is much more efficient for metal recovery than Gly. Under selected experimental conditions (sorbent dosage 1.5 g L^?1), the sorption efficiency is not sufficient for achieving the standard levels for drinking water: the most problematic metal ions in terms of drinkability remain aluminum (too high metal concentration in the groundwater), cadmium, and chromium for the three wells (and nickel in the case of only one well). Increasing the sorbent dosage improves the treatment efficiency. The sorbent (HGly) was tested in fixed-bed columns. The breakthrough curves were compared for the different metals for the groundwater collected in the most contaminated of the three wells. The levels of metal concentration in the treated groundwater are too high for direct use in irrigation. However, they are consistent with the standards for livestock drinking water (based on FAO recommendations, Food and Agriculture Organization of the United Nations). The metals can be readily desorbed using 0.5 M HCl solutions with a relatively high concentrating effect (i.e., 50 times). The re-use of the sorbent for three successive cycles of sorption/desorption cycles shows a progressive but weak decrease in sorption and desorption performances.     

Possibility of using three invasive non-forest tree species as an alternative source for energy production

Non-woody biomass species have high-energy potentials, which could be used for bioenergy production. Invasive species are species spreading into areas, where they are not native, consequently causing environmental and economic problems. Therefore, the present study evaluated the proximate, ultimate, chemical, and fuel characteristics of wood and charcoal of three invasive non-forest tree species in Saudi Arabia: Calotropis procera, Rhazya stricta, and Phragmites australis, which were compared with the wood of Acacia tortilis, a preferable local fuelwood. All these data were discussed to investigate the possibility of using the invasive plants for energy production. The thermal behavior of wood was analyzed using thermo-gravimetric and derivative thermo-gravimetric methods. Overall, compared with the wood of A. tortilis, the woods of R. stricta and P. australis are suitable for energy production. The charcoal produced from P. australis emitted less nitrogen (N) oxide than that of R. stricta.     

Effects of conocarpus biochar on hydraulic properties of calcareous sandy soil: influence of particle size and application depth

A laboratory column experiment was conducted to investigate the effects of 400°C biochar at application rate of 15 g kg^?1 (21.9 t ha^?1) with different particle sizes (<0.5 mm (S₁), 0.5–1 mm (S₂) and 1–2 mm (S₃)) and application depths (0–2 cm depth (D₀), 4–6 cm depth (D₅) and 8–10 cm depth (D₁₀)) on hydro-physical properties of sandy loam soil. The results indicated that applying biochar decreased the waterfront and saturated hydraulic conductivity of sandy loam soil. The cumulative evaporation was the highest and amounted to 40.9 mm in the non-treated soil, but it recorded the lowest amount of 32.2–35.5 mm in the biochar-treated soil. Applying biochar caused significant increases in the amount of conserved and retained water with the highest amount of water conserved in soil treated with S₂ biochar at D₅. Moreover, the cumulative water infiltration through the soil was significantly reduced by S₁ and S₂ biochars at D₀. The values of saturated hydraulic conductivity for biochar treatments were significantly lower than those for the control, with the lowest values for S₁ at D₀ and D₅. These results suggest positive improvement for the hydro-properties of coarse-textured soils following biochar addition, especially with finer particles of biochar.     

Estimates of genetic parameters and correlation of morphological and physiological responses among accessions of cowpea screened under drought stress at the vegetative stage

Journal of Crop Science and Biotechnology - Drought is one of the major limiting factors to cowpea growth and productivity. However, improvement for drought tolerance requires adequate knowledge of...     

Methyl isothiocyanate volatilization from fields treated with metam‐sodium

Emission of methyl isothiocyanate (MITC) from fields treated with metam‐sodium (sodium N‐methyldithiocarbamate) is a potential environmental and human safety hazard. Concentrations of MITC at three heights above four arable fields were measured following the application of metam‐sodium at a rate of 480 litre ha⁻¹ (166 kg AI ha⁻¹). Two of these fields were treated by injection into a center‐pivot irrigation system (chemigation), while in the other two fields the fumigant was applied through injection directly into the soil. Generally, higher MITC air concentrations were observed above chemigated than above injected fields. Maximum MITC air concentrations were 11.2 and 7.4 µg m⁻³ recorded 10 cm above ground 6–8 h following application and the minimum concentrations were 0.7 and 0.2 µg m⁻³ observed at 200 cm 30–35 h after application above chemigated and injected fields, respectively. The estimated MITC respiratory exposure a worker might encounter during the re‐entry period ranged between 1.37 and 0.03 mg day⁻¹ in chemigated fields and between 0.35 and 0.02 mg day⁻¹ in the injected fields. These results suggest that application of the fumigant through injection reduced MITC volatilization losses in comparison with the chemigation method, thus posing a relatively lower risk of exposure to MITC emissions. © 2000 Society of Chemical Industry     

Untapped Potential of Marine-Associated Cladosporium Species: An Overview on Secondary Metabolites,Biotechnological Relevance,and Biological Activities

The marine environment is an underexplored treasure that hosts huge biodiversity of microorganisms. Marine-derived fungi are a rich source of novel metabolites with unique structural features, bioactivities, and biotechnological applications. Marine-associated Cladosporium species have attracted considerable interest because of their ability to produce a wide array of metabolites, including alkaloids, macrolides, diketopiperazines, pyrones, tetralones, sterols, phenolics, terpenes, lactones, and tetramic acid derivatives that possess versatile bioactivities. Moreover, they produce diverse enzymes with biotechnological and industrial relevance. This review gives an overview on the Cladosporium species derived from marine habitats, including their metabolites and bioactivities, as well as the industrial and biotechnological potential of these species. In the current review, 286 compounds have been listed based on the reported data from 1998 until July 2021. Moreover, more than 175 references have been cited.     

Evaluating physiological traits to complement empirical selection for wheat in warm environments

The response of spring wheat to heat stress has been determined in several hot wheat growing environments worldwide on different types of germplasm. Physiological data has been collected to identify potential traits to assist in the empirical breeding for heat tolerance. Initial studies focused on 10 established varieties to determine genetic diversity for heat tolerance, identify association between heat tolerance and traits measured, and evaluate genotype by environment interaction (G x E). Yields from over 40 hot environments were analysed for G x E, and relative humidity (RH) was identified as the major factor determining relative genotype ranking. Further analysis focused on 16 environments: those with low RH and relatively high yields, i.e., over 2.5 t ha^-1. For these environments, mean yield of lines correlated with a number of physiological traits measured in Mexico, including canopy temperature depression (CTD), membrane thermostability, leaf conductance and photosynthetic rate at heading, chlorophyll content during grainfilling, leaf internal CO₂ concentration, and dark respiration. Morphological traits were measured in all environments and the following showed associations with yield: above ground biomass at maturity, days from emergence to anthesis and to maturity, grain number m^-2, and ground cover estimated visually after heading. Subsequent studies focused on breeding material, namely recombinant inbred lines derived from crosses between parents of contrasting heat tolerance, and 60 advanced breeding lines selected for performance under heat stress. The genetic basis for association between heat tolerance and CTD was established by demonstrating a correlation between the two traits in RILs (recombinant inbred lines). Data from RILs, as well as from the 60 advanced lines grown at several international locations, indicated CTD to be a powerful and robust selection criterion for heat tolerance. This revised version was published online in August 2006 with corrections to the Cover Date.     

Strong fisheries management and governance positively impact ecosystem status

Fisheries have had major negative impacts on marine ecosystems, and effective fisheries management and governance are needed to achieve sustainable fisheries, biodiversity conservation goals and thus good ecosystem status. To date, the IndiSeas programme (Indicators for the Seas) has focussed on assessing the ecological impacts of fishing at the ecosystem scale using ecological indicators. Here, we explore fisheries ‘Management Effectiveness’ and ‘Governance Quality’ and relate this to ecosystem health and status. We developed a dedicated expert survey, focused at the ecosystem level, with a series of questions addressing aspects of management and governance, from an ecosystem‐based perspective, using objective and evidence‐based criteria. The survey was completed by ecosystem experts (managers and scientists) and results analysed using ranking and multivariate methods. Results were further examined for selected ecosystems, using expert knowledge, to explore the overall findings in greater depth. Higher scores for ‘Management Effectiveness’ and ‘Governance Quality’ were significantly and positively related to ecosystems with better ecological status. Key factors that point to success in delivering fisheries and conservation objectives were as follows: the use of reference points for management, frequent review of stock assessments, whether Illegal, Unreported and Unregulated (IUU) catches were being accounted for and addressed, and the inclusion of stakeholders. Additionally, we found that the implementation of a long‐term management plan, including economic and social dimensions of fisheries in exploited ecosystems, was a key factor in successful, sustainable fisheries management. Our results support the thesis that good ecosystem‐based management and governance, sustainable fisheries and healthy ecosystems go together.     

Effect of Bay (Laurus nobilis L.) Essential Oil on Surimi Gels Nutritionally Enhanced with Salmon and Flaxseed Oils

Bay essential oil (BEO) at 0.5 and 1 g/100 g was added to surimi gels fortified with omega (ω)-3 rich oils. Although the fortification resulted in increased (P < 0.05) susceptibility of surimi to lipid oxidation, 0.5 g/100 g BEO significantly reduced TBARS (P < 0.05). Addition of ω-3 rich oil or BEO improved the texture. Color values of the surimi seafood were improved particularly when BEO was added. Sensory properties, water activity, and pH values were generally within the acceptable range. These results suggest that the incorporation of BEO may allow food manufacturers to nutritionally enhance surimi seafood with beneficial ω-3 rich oils.     

Spatial analysis of soil surface hydraulic properties: Is infiltration method dependent?

The management of irrigated agricultural fields requires reliable information about soil hydraulic properties and their spatio-temporal variability. The spatial variability of saturated hydraulic conductivity, K_s and the alpha-parameter α_vG-2007 of the van Genuchten equation was reviewed on an agricultural loamy soil after a 17-year period of repeated conventional agricultural practices for tillage and planting. The Beerkan infiltration method and its algorithm BEST were used to characterize the soil through the van Genuchten and Brooks and Corey equations. Forty field measurements were made at each node of a 6 m × 7.5 m grid. The soil hydraulic properties and their spatial structure were compared to those recorded in 1990 on the same field soil, through the exponential form of the soil hydraulic conductivity given by the Gardner equation, using the Guelph Pressure Infiltrometer technique. No significant differences in the results obtained in 1990 and 2007 were observed for either particle-size distribution or dry bulk density. The mean value of α_vG-2007 was found to be identical to that of α_G-1990, while that of K_s-2007 was significantly smaller than that of K_s-1990. In contrast to the Gardner equation, the van Genuchten/Brooks and Corey expression was found to be more representative of a well-graded particle-size distribution of a loamy soil. The geostatistical analysis showed the two parameters, K_s and α_vG-2007, were autocorrelated up to about 30 and 21 m, respectively, as well as spatially positively correlated within a range of 30 m. Despite the difference in the mean values of K_s between the two studies, the spatial structures were similar to those found in the 1990 experiment except for the covariance sign. The similarity in autocorrelation ranges indicate that the spatial analysis of soil hydraulic properties is independent of the infiltration methods (i.e., measurement of an infiltration flux) used in the two studies, while the difference in the covariance sign may be linked to the use of two different techniques of soil hydraulic parameterization. The covariance values found in the 2007 campaign indicates a positive relationship between the two parameters, K_s and α_vG-2007. The spatial correlations of soil hydraulic parameters appear to be temporally stabilized, at least within the agro-pedo-climatic context of the study. This may be attributed to the soil textural properties which remain constant in time and to the structural properties which are constantly renewed by the cyclic agricultural practices. However, further experiments are needed to strengthen this result.