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Effect of Sodium Chloride-induced Salinity on Phyto-availability and Speciation of Cd in Soil Solution
2007
Ghallab, Ahmed | Usman, Adel Rabie Ahmed
A greenhouse experiment with two levels of Cd (0.5 and 10 mg Cd kg-¹, in the form of CdCl₂), and five salinity levels of irrigation water (0, 8.6, 17.1, 34.2 and 68.4 mM NaCl) in triplicate was conducted to determine the effect of NaCl-induced salinity on the solubility and availability of Cd in clay loam and sandy calcareous soils. Corn seeds (Zea mays L.) were sown in pots. Forty-five days after planting, the shoots were harvested, and their Cd concentration was determined. The post-harvest electrical conductivity (ECe), pH, and concentrations of cations and anions were determined in soil saturation paste extracts. Increasing irrigation water salinity resulted in significant increases in the total soluble Cd concentration in both studied soils. A positive correlation was found between the total soluble Cd and the chloride concentration in the soil solution.Solution speciation, calculated with MINEQL+ (a chemical equilibrium modeling system), predicted that Cd was present mainly as free Cd²⁺ ions followed by CdCl⁺ and [graphic removed] in the soils irrigated with deionized water. However, Cd species in the soil solution were significantly altered by increasing chloride concentration, with Cd-chloro complexes becoming the dominant Cd species in the soil solution. Increasing the salinity level resulted in significant decreases in the shoot dry matter and increases in the shoot Cd concentration. Shoot Cd concentration was positively correlated with both the total Cd and Cd-chloro complexes in the soil solution.
Mostrar más [+] Menos [-]Hydrogeochemistry and Water Balance in the Coastal Wetland Area of “Biviere di Gela,” Sicily, Italy
2007
Manno, E. | Vassallo, M. | Varrica, D. | Dongarra, G. | Hauser, S.
In the study area physical and chemical factors control the composition of surface and groundwaters, which in turn determine the water quality of the “Biviere di Gela” lake. These factors combine to create diverse water types which change their compositional character spatially as rainfall infiltrates the soil zone, moves down a topographically defined flow path, and interacts with bedrock minerals. Low-salinity waters, which represent the initial stage of underground circulation, start dissolving calcium carbonate from the local rocks. The progressive increase in salinity, characterized by substantially higher Ca, SO₄, Na and Cl concentrations, suggests that dissolution of CaSO₄ and NaCl is an important process during water-rock interactions. The “Biviere di Gela” lake is often separated into two units (Lago Grande and Lago Piccolo). “Lago Grande” water is generally of Na-SO₄-Cl-type, whereas “Lago Piccolo” water is of Na-Cl-SO₄-type. Their total content of dissolved salts varies with season, the amount of rainfall, and inflow of ground and drainage water. Over time, an increasing trend towards greater salinity and also sudden changes in the relative abundances of Cl and SO₄ have been recorded for the “Lago Grande.” The isotope composition of the lake water appears to be affected by inflow of ground and surface waters and also by evaporative loss. The nitrate content of waters from the recharge basin is of particular concern because it contributes to lake eutrophication. The trace element contents do not evidence the presence of any significant metal contamination of lake waters, although a future potential hazard of metals bioaccumulation by the aquatic biota must be taken into consideration. Finally, a water balance for the basin shows that a drop in precipitation of about 20% might be critical for lake survival.
Mostrar más [+] Menos [-]Algological research of the Novo Ilje 1 and Novo Ilje 2 near Melenci (Vojvodina, Serbia)
2007
Fuzinato, S.,Univerzitet u Beogradu, Beograd (Serbia). Bioloski fakultet | Fodora, A.,Univerzitet u Beogradu, Beograd (Serbia). Bioloski fakultet | Subakov-Simic, G.,Univerzitet u Beogradu, Beograd (Serbia). Bioloski fakultet | Krizmanic, J.,Univerzitet u Beogradu, Beograd (Serbia). Bioloski fakultet
The puddles Novo Ilje 1 and Novo Ilje 2 are aquatic ecosystems periodically filled with moderate salt and alkaline water. In 2003 and 2004 quantitative analysis show the Euglenophyta domination. Trachelomonas taxa are the most common. The algae in planktonic communities are the most numerous in both puddles in researched years.
Mostrar más [+] Menos [-]Phytoplankton production of the Velika Slatina near Opovo [Serbia]
2007
Subakov-Simic, G.,Bioloski fakultet, Beograd (Serbia) | Karadzic, V.,Institut za javno zdravlje Srbije Dr Milan Jovanovic-Batut, Beograd (Serbia) | Krizmanic, J.
The salt pond Velika Slatina is the old meander of the river Tamis (Serbia). The ecosystem is periodically fill with moderate salt water. Phytoplankton production was 10 times bigger in 2003 than 2006. Ecological conditions were unfavourable for development of phytoplankton community. Diatoms show as the most abundant component in 2003, but euglenoids were in 2006, when bloom of Gloeotrichia natans f. bucharica Kissel was recorded. Results of biomass analysis also show dominant role of diatoms in 2003 and euglenoids in 2006.
Mostrar más [+] Menos [-]Monitoring the quality of irrigation water pumped from the first aquifer
2007
Nesic, Lj.,Poljoprivredni fakultet, Novi Sad (Serbia) | Maksimovic, L.,Naucni institut za ratarstvo i povrtarstvo, Novi Sad (Serbia) | Pejic, B.,Poljoprivredni fakultet, Novi Sad (Serbia) | Dragovic, S.,Naucni institut za ratarstvo i povrtarstvo, Novi Sad (Serbia)
Quality of irrigation water taken from three wells located at Rimski Sancevi near Novi Sad, Serbia, has been monitored for three years. The obtained results showed that the samples from the three wells had a relatively uniform quality. We are dealing with a mineralized water which may increase the salinity of poorly drained soil but it cannot cause soil alkalization because of low sodium levels. In view of the above, it is recommended to periodically check not only irrigation water quality but also soil salinity level.
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