Monitoring microbial biomass and respiration in different soils from the Czech Republic--a summary of results

The microbial biomass (Cbio), respiration (basal respiration (BR) and potential respiration (PR)), and derived indices for 520 independent soil samples of 117 different soils from the Czech Republic were statistically analysed. The broad range of soil samples allowed the stepwise breakdown of the database into six reasonable categories of soil: arable soils, loamy grassland soils, sandy grassland soils with weak organic matter content, sandy grassland soils with moderate organic matter content, forest soils with moderate organic matter content, and forest organic soils with rich organic matter content. Because soil microbiology lacks benchmarking values, the ranges of the microbial characteristics for these categories were stated and are presented here. The separation into soil groups narrowed the ranges enough to be useful for comparative purposes. The groups displayed significant differences in basal microbial parameters. The lowest microbial biomass was found in arable soils and grassland sandy soils with weak organic matter content. The highest microbial biomass was shown by loamy grassland soils and organic forest soils. Respiration displayed similar results to the microbial biomass. The derived indices revealed less significant differences confirming their inner-standard nature. The relationships between the soil contamination and microbial parameters were not explored because of the confounding effect of soil organic matter. However, it was not shown by the category of grassland sandy soils with weak organic matter content suggesting they could be especially suitable for the biomonitoring of harmful effects of chemicals on soil microorganisms.     

Low NOx burners--prediction of emissions concentration based on design,measurements and modelling

This paper describes possible ways of prediction of nitrogen oxides formation during combustion of hydrocarbon fuels. Mathematical model based on experimental data acquired from the testing facility has been developed. The model enables to predict--at a high probability measure--the extent of nitrogen oxides emissions. The mathematical model of nitrogen oxide formation relies on the application of simplified kinetic equations describing the formation of nitrogen oxides at so-called equivalent temperature. It is a semi-empirical model that comes out of experimental knowledge. An important role played by the burner design itself has been emphasized and therefore an important supplementary parameter of the model is the characteristic of the burner design. It has been established that there was a good agreement between experimental data and those calculated by the application of the model to various conditions marked out by different combustion parameters in the combustion chamber. The results obtained by application of the model respect the influence of parameters validated by industrial practice that control the formation of nitrogen oxides in the course of fuel combustion. Such parameters-first of all-tare the temperature in the combustion chamber and the concentration of the substances taking part in the reaction. By application of the model, it is possible to assess the consequence of, for example the surplus of combustion air, the increase of temperature of combustion air, the supply of inert gas, etc. on the nitrogen oxides emissions of the operating burner under evaluation. Efficient combining of experience and sophisticated approach together with importance of thus access for an improved design are shown.     

A long-term survey of heavy metals and specific organic compounds in biofilms, sediments, and surface water in a heavily affected river in the Czech Republic

To assess the long-term anthropogenic load of the Bílina River (Czech Republic), the concentrations of heavy metals and specific organic compounds in different river ecosystem matrices (water, biofilms, and sediments) were determined. Although the current concentrations of pollutants in surface water are low, frequently below the limits of the quantitative analytical methods used, the river ecosystem is still heavily loaded by anthropogenic pollution, mainly from the chemical and mining industries. This was demonstrated by analyzing biofilms and sediments. These matrices are more accurate representatives of the actual situation in the river and do not depend on hydrological conditions or random variability in water quality. The results indicate that the middle and the lower parts of the river are heavily polluted by mercury, arsenic, vanadium, polychlorinated biphenyls, hexachlorobenzene, and dichloro-diphenyl-trichloroethane. As a tributary of the Elbe River, the Bílina River represents a significant risk for the development of quality in this major European river.