Pollution Abstracts

The propagation of electromagnetic radiation was investigated a t different points, and the theory of covariance was applied to identify the main parameters by recording the max, mean and min values of density. The biggest electric field strength values are emitted by the second generation (2G) GSM mobile phones that operate in the frequency band of 900 MHz. The smaller electric field strength values are determined by the higher frequency (1800 MHz) used by mobile phones and smaller maximum power, the maximum of which reaches up to 1 W. Third generation (3G) UMTS smart phones that operate in the frequency band of 2100 MHz, emit smallest electric field strength values during the conversation. The values of digital arrays of measurement of the electromagnetic field energy flux density of interrelated covar iance functions and digital arrays of individual covariance functions were identified. Data concerning interrelated covariances and auto-covariances of electromagnetic field energy flux density in a time scale are presented by means of the Matlab 7 software package.

The paper analyses the impact of a hydropower plant (HPP) on environment, first at all on downstream riverbed reach and also on fish community. Frequent switching of the turbines is determined to cause intensive long lasting riverbed scour and significant reduction in fisf community. Each switching of the HPP turbines is known to induce a sudden change of water discharge and level in a downstream reach. Water level suddenly drops down after the turbine switch off. Uplift force of ground water flowing from a river bed destructs a reinforcing layer of large ground particles formed during the selflinning process. Scour of small particles from the bottom sets in. the riverbed deepens significantly until a new reinforcing layer forms up. The suggestions are given to slow down the turbines switching within technical possibilities. This simple measure makes it possible to increase the leght of a reflux wave, to lower down the rate of water level drop and to reduce the length of a river reach under scour danger.

The aim of this study was to determine speciation of 137Cs in Sea water, suspended particles and bottom sediments in order to better understand the behaviour, redistribution and sink of the mentioned nuclide in the Lithuanian coastal area of the Baltic Sea. Activity concentrations and speciation of 137Cs in the Baltic Sea suspended matter and bottom sediments of different size particles were determined. The modified Tessier method was used to study caesium associations with geochemical phases of bottom sediments. The sorption-desorption of 137Cs was observed during the transport of suspended particles from the Curonian Lagoon to the Baltic Sea. An increase in the specific activities of 137Cs (over 1000 Bq kg) in fine particles may be observed due to increase in the specific surface area of sediments participating in sorption processes. Another possible explanation of this deals with the variation in mineralogical composition of different size particles. However, a strong correlation was found both between specific activity of 137Cs and the content of clay particles (r=0.95, n=16) and the amount of organic substances (r=0.75, n=16). Our study indicated complicated sorption-desorption behaviour of 137Cs in the Baltic Sea water in a result of which it can be mobilised by suspended particles or released to the Sea water. The fate of 137Cs can be considerably affected by mineralogical composition of suspended and bottom sediments, by characteristic geochemistry of sea water and the presence of other pollutants.