Complementary aspects of linear flood routing modelling and flood frequency analysis

Similarity and differences between linear flood routing modelling (LFRM) and flood frequency analysis (FFA) techniques are presented. The moment matching used in LFRM to approximate the impulse response function (IRF) was applied in FFA to derive the asymptotic bias caused by the false distribution assumption. Proceeding in this way, other estimation methods were used as approximation methods in FFA to derive the asymptotic bias. Using simulation experiments, the above investigation was extended to evaluate the sampling bias. As a feedback, the maximum likelihood method (MLM) can be used for approximating linear channel response (LCR) by the IRFs of conceptual models. Impulse responses of the convective diffusion and kinematic diffusion models were applied and developed as FFA models. Based on kinematic diffusion LFRM, the equivalence of estimation problems of discrete‐continuous distribution and single‐censored sample are shown both for the method of moments (MOM) and the MLM. Hence, the applicability of MOM is extended for the case of censored samples. Owing to the complexity and non‐linearity of hydrological systems and resulting processes, the use of simple models is often questionable. The rationale of simple models is discussed. The problems of model choice and overparameterization are common in mathematical modelling and FF modelling. Some results for the use of simple models in the stationary FFA are presented. The problems of model discrimination are then discussed. Finally, a conjunction of linear stochastic processes and LFRM is presented. The influence of river courses on stochastic properties of the runoff process is shown by combining Gaussian input with the LCR of the simplified Saint Venant model. It is shown that, from the classification of the ways of their development, both LFRM and FFA can benefit. Copyright © 2006 John Wiley & Sons, Ltd.     

Geochemical characteristics of the macromolecular part of crude and biodesulphurised flame coal density fractions

Flame coal (Janina Mine, Poland) was an object of geochemical analyses for changes caused by the process of microbial desulphurisation. Ash content, beryllium, chromium, zinc, cobalt, lithium, manganese, copper, molybdenum, nickel, lead and vanadium concentrations were investigated in coal extracts, its macromolecular part, semi-coke and polar compound fractions of extracts and pyrolysates of crude and biodesulphurised coal density fractions. The macromolecular part of extracted density fractions was pyrolysed giving semi-coke and pyrolysate. These were separated into aliphatic hydrocarbons, aromatic and polar compounds by thin layer chromatography (TLC). Distributions of aliphatic and aromatic hydrocarbons in pyrolysates of the crude and desulphurised coal density fractions were compared by gas chromatography-mass spectrometry (GC-MS). Extracts, extracted density fractions, semi-coke and polar compound fractions were analysed for concentrations of trace elements. In the crude coal their concentrations in the macromolecular part are related only to coke. However, in the desulphurised coal the participation of the particular trace element increases in pyrolysate polar compound fractions. Its values are in the range from 1% (Mn) to 100% (Cr and Mo). These changes are the best seen in the 1.80-2.30×10³ kg/m³ density fraction. Very high concentrations of trace elements were found in pyrolysate of desulphurised coal density fraction. This can be explained by the partial decomposition of coal macromolecule resulting from desulphurisation. Significant side-cleavage of peripheral groups and lighter aromatic hydrocarbons is possible. The effects of bacterial influence were manifested by the increase of polar compounds contents both in pyrolysates and extracts of the desulphurised coal and changes in distribution of aliphatic and aromatic hydrocarbon as pyrolytical products. These effects increase with mineral substance contents. Moreover, the increase of trace element concentration in coal organic matter occurs. It is reflected by the increase of participation of coal pyrolysate polar fraction in the total concentration of analysed elements in the macromolecular part of a given density fraction. The presented results are a part of the larger research aimed to find an influence of desulphurisation on chemical and technological properties of coal.     

Environmental challenges in Polish agriculture covering a main area of the Baltic Sea Basin

Poland largely encompases the estuary of the Vistula and Odra rivers, which drain into the Baltic Sea. Only a very small area of the south-east part of the country is within the Black Sea Basin. Poland contributes significantly to the pollution of the Baltic Sea, with biogenic nutrients and organic substances. Poland includes more than half the coastal inhabitants of the Baltic Sea, and they use 40% of the arable land situated there. The contribution to the pollution of this sea with nitrogen, phosphorus and organic substances is approximately 30, 40 and 22%, respectively. The main sources of nutrients are untreated sewage and the runoff and leakage of fertilizers from agricultural land. The natural conditions in Poland are poorer than in Western Europe due to the prevalence of light soils and a short growing period with frequent droughts. After correcting the synthetic index for soil and climate, it was estimated that for each inhabitant of Poland there are 0.3 ha of farmland, which is comparable to that of Western Europe. For the maintenance of the population, intensive agricultural production must be accompanied by environmental protection regulations. Polish agriculture is not only a polluter but also a recipient of pollution, especially the deposits of sulphur and heavy metals emitted by industry and municipal areas. The estimated annual emission of sulphur dioxide is about 4 million t, which equals an average deposit of about 90 kg of sulphur per hectare of farmland. The pedological processes and acid deposits cause more than 60% of agricultural land in Poland to be acidic. The contamination of soils with heavy metals in general is lower than in Western Europe, but in some areas (e.g. Upper Silesia) it exceeds the safe limits.     

Gas stream in Algol

Additional absorption features in the red wings of the resonance Mgii lines near 2800 Å are found in the observations of Algol made by Chen and Wood (1976) from theCopernicus satellite. The absorption features were clearly seen only during a part of the primary eclipse, in the phase interval 0.90–0.03.The observations are interpreted as produced by a stream of matter flowing from Algol B in the direction of Algol A. The measured Doppler shifts of the features give the value of 150 km s^–1 as the characteristic velocity of matter in the stream. The mass transfer connected with the stream is estimated to be of the order of 10^–13 M yr^–1.     

Fossil sulphate-reducing bacteria in the Bleiberg lead-zinc deposit, Austria

Polished ore samples from the world-class Bleiberg lead-zinc deposit in Austria were studied by Field Emission Scanning Electron Microscopy (FESEM) at magnifications in the range of 10⁵–10⁶. The zinc ore shows nano-sized sphalerite filaments and spherules which are morphologically similar to recent biofilms of sulphate-reducing bacteria. The activity of sulphate-reducing bacteria is suggested by a large ³⁴S difference of ~40 between coeval seawater sulphate (+16 ) and sulphide sulphur (< –25 ) in the Bleiberg ores, and by variable sulphur valences. Peloids of sphalerite, Zn-bearing calcite and pyrite have features typical of bacterial colonies. Combined with geological and mineralogical evidence, a significant role of bacteria during ore deposition at Bleiberg is likely.Eugen F. Stumpfl deceasedEditorial handling: B. Lehmann     

The role of sulphide and carbonate minerals in the concentration of chalcophile elements in the bituminous coal seams of a paralic series (Upper Carboniferous) in the Upper Silesian Coal Basin (USCB), Poland

Sulphide and carbonate minerals from nine bituminous coal seams of a Paralic Series were investigated by means of polished-section microscopy, scanning electron microscopy and absorption spectral analyses. In addition to syngenetic accumulations of kaolinite, illite and quartz, diagenetic veinlets of subhedral pyrite and marcasite most often occur in vitrinite clast fissures and in post-tectonic fissures, nests and lenses with fusinite. Epigenetic anhedral and subhedral grains of ankerite, dolomite, siderite and calcite are also frequently found in post-tectonic veins. Pyrite replaced some of the marcasite grains and it dominates in older coal seams in the Flora Beds as compared with the Grodziec Beds. Occasionally there are anhedral and subhedral galena, sphalerite and chalcopyrite grains among coal macerals as well as cerussite among post-tectonic carbonate veins. They all represent the only minerals that are abundant in definite chalcophile elements (Cd, Co, Cu, Ni, Pb, Zn). In addition to the minerals just mentioned, the elements occurred in pyrite and ankerite grains, which contained inclusions of fusinite and other minerals (among others, clay and carbonate minerals in pyrite, pyrite in carbonates). Although there is a low content of minerals accumulating Cd, Co, Cu, Ni, Pb and Zn, the minerals significantly influence the average concentration of elements in the coal seams. In the Grodziec Beds, mineral matter, especially carbonates and sulphides, determines (>50%) the concentration of Cd, Cu, Pb and Zn in coal. The basic part of Cd, Co and Ni in the coal seams of the Grodziec Beds and of Co, Cu, Ni, Pb and Zn in coal seams of the Flora Beds originates from organic matter. These regularities can be important, from an ecological perspective, in stating whether the coals investigated are useful for combustion and in chemical processing.