Issue 4

Natural diversity of intermittently closed and open lakes and lagoons (ICOLLs) depends on mutual interactions of several factors: (i) an impact of sea water and land background; (ii) temporary meteorological situation; (iii) hydrological conditions; and (iv) the shape of lake basin. However, some regional, local or even sudden impacts including anthropogenic ones create their final ecological status. To identify heavy metals risk assessment in ICOLLs located in Polish coastline wide range of them were determined in water and bottom sediment samples collected in 10 water reservoirs. Multidimensional data set of 20 variables was explored by the use of chemometrics according to seasonality (Spring, Summer, Autumn), sample type (water, sediment) and level of isolation (fully isolated, partially and fully connected lakes). The results showed that 70.5% and 77% of the data variance can be explained by the use of principal component analysis for waters and sediments, respectively. Waters of fully isolated or partially connected lakes are more abundant with Ir, Nd and Sm, while less abundant with Pr and Sr. Bottom sediments taken from Jamno lake show significant contamination by heavy metals of the highest environmental concern (Al, Cr, Cu, Ni, Ti and Zn).

Heavy metals are one of the main pollutants of river, lake and canal sediments. Stabilization technology proved to be an effective method for solving this problem. Stabilization covers a wide range of remediation techniques that are used to transform waste into forms that will be less problematic for the environment. Stabilization of the Great Backi Canal sediment was carried out by using nanomaterials, namely nano zero-valent iron (nZVI). Two different approaches for the synthesis of nanomaterials were used, conventional and so-called "green" method. For conventional, borohydridemethod, nZVI was stabilized with native clay as porous material which proved to be very effective because of its specific surface area. Extract of oak leaves was used for green method which contains polyphenols as promising agents for the nZVI synthesis. Assessment of the treatment efficiency was performed by using semi-dynamic leaching test ANS 16.1. In order to stimulate leaching conditions, similar to those at the landfill, ANS 16.1 method was modified by using humic acid solution. These results showed that metals were successfully immobilized in the sediment.

Application of municipal sewage sludge (MSS) to agricultural soils is a current practice in EU. European legislation permits its use in agriculture when concentrations of metals in soil do not exceed the maximum permissible limits. In order to study the influence of MSS on cotton yield and soil properties, a filed experiment was conducted in a soil classified as Typic Xerochrepts located in Lamia area, central Greece, for two consecutive years. The experimental design was complete randomized blocks with four treatments: Control (C ), inorganic fertilization (IF), application of 6000 dry kg ha-1 MSS, and 10000 dry SS kg ha-1, each replicated 4 times. The results showed that MSS application in both rates, increased significantly cotton yield compared to control equally to inorganic fertilization. Soil properties, at the end of the second year of MSS application, were significantly affected by MSS application in a positive way i.e. pH decreased slightly, but organic matter content, available phosphorus, total nitrogen concentrations exchangeable potassium and available zinc and copper increased significantly. The potentially toxic elements lead, chromium, and nickel were not significantly affected by MSS application in both application rates compared to control.

This paper describes the adsorption of Al3+ ions from aqueous solutions, by natural clay (from Sakarya's Yenigün district) and coconut shell modified by means of acid treatment. Batch experiments were carried out to determine the effect of various factors such as initial pH (4-9), temperature (20, 40, 70 oC), initial concentration (10 to 200 mg L-1) and contact time (1-120 minute) on the adsorption process. The adsorption experiments were performed at a temperature of 20 ±2 oC), at 200 rpm agitation rate, with an adsorbent level of 1 g L-1, produced 98.95% (at pH 6) and 92.83% (at pH 7) maximum Al3+ removal efficiency for clay and coconut shell based adsorbents respectively. Furthermore, the process was found to be exothermic for clay and endothermic for coconut. XRF and XRD analyses of the clay variety used in adsorption analyses revealed it to be saponite clay, within the larger group of smectite clay minerals. The application of Langmuir revealed maximum adsorption capacity of 149.25 mg g-1 for natural clay adsorbent (NCA), and 120.482 mg g-1 for coconut shell adsorbent (CSA). Moreover, adsorption kinetics were found to be consistent with the second order kinetics (R2 > 0.95). The result shows that, natural clay and coconut shell adsorbents are effective adsorbents to remove Al3+ from aqueous solutions with good adsorption rate (>92.8%).