Mercury pollution of Mediterranean sediments around Alexandria,Egypt

Elemental mercury is associated with industrial wastes discharged through the main effluent pipe of the Chlorine-Alkali plant at El-Max area west of Alexandria. The minimal mercury value of 0.1 ppm dry weight is assumed to be the background level for uncontaminated sediments in the area. Mercury level ranged from 8.02 to 15.5 ppm in the beach sands from the polluted area beyond the plant, and from 0.14 to 1.4 ppm in the bottom sediments off Alexandria.The Chlorine-Alkali plant is obviously the major source of mercury pollution. The contribution of land drainage, agricultural and domestic wastes is insignificant.     

Geothermometry applications for the Balıkesir thermal waters,Turkey

In this study, reservoir temperatures of Balıkesir geothermal waters in northwestern Turkey are estimated with various geochemical models. The geothermal fluids in the region are represented by Na–SO₄, Na–HCO₃ and Ca–HCO₃ type waters with discharge temperatures up to 98°C. It was determined that the solubility of silica in most of the waters is controlled by the chalcedony phase. Equilibrium states of the Balıkesir thermal waters studied by means of Na–K–Mg–Ca diagram, mineral saturation calculations and activity diagrams in the system composed of Na₂O–CaO–K₂O–Al₂O₃–SiO₂–H₂O phases approximate a reservoir temperature of about 120°C. Most of the waters are found to be equilibrated with calcite, chalcedony ± quartz and muscovite at predicted temperature ranges, similar to those calculated from the chemical geothermometers.     

Quantifying uncertainties associated with depth duration frequency curves

Uncertainty in depth–duration–frequency (DDF) curves is usually disregarded in the view of difficulties associated in assigning a value to it. In central Iran, precipitation duration is often long and characterized with low intensity leading to a considerable uncertainty in the parameters of the probabilistic distributions describing rainfall depth. In this paper, the daily rainfall depths from 4 stations in the Zayanderood basin, Iran, were analysed, and a generalized extreme value distribution was fitted to the maximum yearly rainfall for durations of 1, 2, 3, 4 and 5 days. DDF curves were described as a function of rainfall duration (D) and return period (T). Uncertainties of the rainfall depth in the DDF curves were estimated with the bootstrap sampling method and were described by a normal probability density function. Standard deviations were modeled as a function of rainfall duration and rainfall depth using 10⁴ bootstrap samples for all the durations and return periods considered for each rainfall station.