Articles in Press

A novel method that utilizes a combination of statistical and clustering techniques is presented in order to classify statistically independent heavy rainstorm events and create a limited number of temporal distribution curves. These curves represent the centers of many unitless cumulative rainstorm events and express the temporal distribution patterns in a probabilistic way. The whole process includes the necessary steps from importing raw precipitation time series data to producing the initially unknown optimal number of representative curves. These hyetographs can be used for stochastic simulation, water resources planning, water quality assessment and global change studying. The present type of analysis is fully unsupervised, as no empirical knowledge of local rainfalls is implicated or any arbitrary introduction of quartiles for grouping as is the case in the pertinent literature. An example using data from a Greek Water Division illustrates that the proposed method produces clusters with superior internal structure and temporal distribution curves that are not coming from the same distribution, in contrast to the results using Huff’s curves classification.

A simulated wetland experiment was used to investigate the effect of cadmium (Cd) on the growth of Arundo donax, as well as its photosynthetic characteristics and antioxidant enzyme activities. Cd accumulation in the order of stem < roots < leaves increased gradually with increasing Cd concentrations. Due to the higher transport of Cd, its accumulation in the aboveground parts of A. donax was nearly 2 times that in belowground parts. There were no differences in physiological parameters, such as the relative chlorophyll content (SPAD), the potential (Fv/Fm) or effective (Y) photochemical efficiency of PSII, and photosynthetic rate (Pn). There were slight changes in transpiration rate (Tr), intercellular CO2 concentration (Ci) and stomatal conductivity (Gs). The activity of superoxide dismutase (SOD) was stimulated by Cd treatments, and the decrease in catalase (CAT) was compensated by the induction of peroxidase (POD) suggesting these two enzymes function concurrently to remove H2O2. These results indicate that despite the oxidative stress involved in the mechanism of Cd toxicity associated with the high transport of Cd in A. donax, its photosynthetic system was not harmed. This suggests a strong tolerance of this species to increased Cd pollution and its potential use for phytoremediation purposes in wetland environment.

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.