Variations of anthropogenic CO2 in urban area deduced by radiocarbon concentration in modern tree rings

Radiocarbon concentration in the atmosphere is significantly lower in areas where man-made emissions of carbon dioxide occur. This phenomenon is known as Suess effect, and is caused by the contamination of clean air with non-radioactive carbon from fossil fuel combustion. The effect is more strongly observed in industrial and densely populated urban areas. Measurements of carbon isotope concentrations in a study area can be compared to those from areas of clear air in order to estimate the amount of carbon dioxide emission from fossil fuel combustion by using a simple mathematical model. This can be calculated using the simple mathematical model. The result of the mathematical model followed in this study suggests that the use of annual rings of trees to obtain the secular variations of ¹⁴C concentration of atmospheric CO₂ can be useful and efficient for environmental monitoring and modeling of the carbon distribution in local scale.     

The influence of benzo(a)pyrene on the growth of wheat and corn

Corn seeds responded to soaking in aqueous solutions of benzo(a)pyrene with increased root growth. Growth stimulation decreased from 14% to 0 with increasing concentrations (0.0005–0.02 ppm), and with increasing soaking times (6 and 12 hr). Shoot growth and dry weights of shoots were not affected. Wheat did not respond as distinctly as corn to similar treatments. A decrease in the growth of shoots and roots with increasing BaP concentrations was not statistically significant.     

Effects of zero-valent iron (Fe0) and temperature on the transformation of DDT and its metabolites in lake sediment

Zero-valent iron improves the transformation of DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] and its metabolites in aged and highly contaminated lake sediment under biotic conditions. The addition of Fe0 has a strong effect on transformation rates at 22 degrees C and 9 degrees C, the most enhanced degradation being obtained for DDT and DDOH [2,2-bis(p-chlorophenyl)ethanol]. At 22 degrees C and 10 weeks' incubation, the DDT concentration is reduced from 2.75 micromol g(-1) (974 mg kg(-1)) to 0.98 micromol g(-1) (346 mg kg(-1)) and 1.98 micromol g(-1) (702 mg kg(-1)) in samples with and without the addition of iron, respectively. After 40 weeks' incubation these concentrations have further decreased to 0.19 micromol g(-1) (66 mg kg(-1)) and 0.74 micromol g(-1) (264 mg kg(-1)).There is no significant transformation of any of the compounds at 9 degrees C without the addition of Fe0. In the presence of iron, however, DDT is reduced to 1.25 micromol g(-1) (442 mg kg(-1)) within 40 weeks' incubation. This study demonstrates the ability of adapted microorganisms to transform DDT under elevated temperatures in original, aged sediments, and also the stimulating effect of zero-valent iron, which is significant even at low temperatures.     

Geophysical methods in radon risk studies

The results of the studies presented in the paper have shown that in the Upper Silesian Region in Poland, radon indoor concentration levels depend first of all on the geological structure of the subsurface layers. The essential factors influencing radon migration ability are the mining-induced transformations of a rock mass. In some cases, significant variations of radon potential have been found at sites featuring similar geological structures and experiencing comparable mining effects. To find out the causes of these variations, studies involving geophysical methods such as electrical resistivity profiling (PE) and electrical resisitivity sounding (VES) were used. These studies have shown that the measurements made using the electrical resistivity method can be helpful in evaluating radon potential of both the tectonically disturbed areas and the mining-transformed ones.     

Mercury in wild mushrooms and underlying soil substrate from the great lakes land in Poland

Fifteen species of wild mushrooms and underlying soil samples collected in a virgin landscape of Augustowska Forest in northeastern Poland in 1997-98 were analyzed for total mercury to evaluate the status of contamination and usefulness of higher mushrooms as possible bioindicators of mercury pollution. Among the 15 species analyzed, Pinewood King Bolete, Scaly Tooth and King Bolete showed relatively high bioconcentration factors (BCF: dry-weight normalized concentrations of mercury in mushrooms relative to concentrations in soil) for mercury, which varied between 69 and 110. These three species were also characterized by great concentrations of total mercury in caps (between 2,000 +/- 800 and 2,300 +/- 1,100 ng g-1 dry wt) and stalks (between 850 +/- 390 and 1,000 +/- 500 ng g-1 dry wt.). Species such as Red-hot Milk Cap, Poison Pax and Common Chantherelle had mercury BCFs of less than 1, while Gipsy Bolete, Orange Birch Bolete, Brown Scaber Stalk, Variegated Bolete, Sandy Knight-cap and Yellow-cracking Bolete were weak or moderate mercury accumulators with BCFs between 1 and 40. Concentrations of mercury in mushrooms were greater than the tolerance limits suggested for mercury in plant foods.     

An Investigation into the Influence of Filler Silanization Conditions on Mechanical and Thermal Parameters of Epoxy Resin-Fly Ash Composites

The insulation material of electronic devices should offers high thermal conductivity whilst retaining suitable mechanical properties. Epoxy resin is an example of a material that is commonly used by industry for electronic insulation, despite the fact that neither the thermal conductivity nor the mechanical properties are particularly satisfying. These properties can be enhanced by incorporating filler, with silica flour representing the most popular filler. An economically appealing solution is to replace silica flour with fly ash as filler material, however it must be remembered that compatibility of fly ash and epoxy resin is not ideal. In order to improve the coupling between these two materials, fly ash particles covered with [3-(2-Aminoethylamino)propyl]trimethoxysilane were obtained with six different conditions of the silanization process, where the amount of silane, the temperature and the time of the reaction were changed. The presence of the silane layer was confirmed via Fourier Transform Infrared Spectroscopy, Thermogravimetric Analysis and Scanning Electron Microscopy. The mechanical properties, including tensile strength, Young Modulus and fracture toughness, as well as the thermal conductivity of the final samples were investigated. In the case of composites with silanized fillers, all of the mechanical properties were improved, and an enhancement of thermal conductivity was observed for several composites. Moreover, the differences in coupling between the silanized fly ash and the untreated fly ash, and the epoxy matrix were precisely recorded by means of SEM. The presented studies confirm that an effective silanization process can significantly improve the properties of composites, while also verifying the usefulness of waste material. The results highlight that fly ash may be utilized to create a more economically affordable insulation material.     

Monitoring nutrient transport in large rivers

The problem of estimating nutrient transport in large rivers and the uncertainty of such load estimates was studied both empirically and theoretically. In the empirical part of the study, time series of data from the Rhine, Meuse, Vistula and Oder Rivers were examined. The results of this data analysis justify the use of linear interpolation to estimate concentrations prevailing between sampling occasions. A special study of the spatial variation of concentrations within different cross-sections of the Vistula river showed that such variation can contribute substantially to the uncertainty of load estimates. In general, however, sampling at one point in the cross-section did not result in biased load estimates. In the theoretical part of the study, simple ARMA (autoregressive-moving average) models were used to derive generally applicable formulas for the expected mean square error of load estimates based on serially dependent concentration data. These formulas were then used to estimate the uncertainty of calculated nutrient loads in the Rhine and the Vistula, respectively.     

The separation of catalyst after photocatalytic reactions conducted in the presence of TiO2/FeCl3/UV

One of the problems connected with wastewater treatment by the photocatalytic method in the presence of TiO2 suspension is necessity of the later catalyst separation. The method proposed by us for this purpose, consists in the usage of coagulation of TiO2 suspension with the aid of FeCl3, particularly in the cases when addition of the salt is used in order to intensification of the photocatalytic process. The effects of the TiO2 separation were studied from the mixtures, after photocatalytic Acid Orange 7 degradation, with dosage of FeCl3 at different stages of the process. The coagulation was carried out at different pH values as well as different FeCl3 concentrations. It was stated that nearly 100% of separation and simultaneously, nearly 100% of decolouration of the examined Acid Orange 7 solutions after their illumination in the presence of TiO2/FeCl3 and coagulation which was produced only by increasing of pH of the obtained mixtures, were nearly possible.     

Shell colour,temperature, (micro)habitat structure and predator pressure affect the behaviour of <Emphasis Type="Italic">Cepaea nemoralis</Emphasis>

Although shell colour polymorphism of the land snail Cepaea nemoralis is a well-known phenomenon, proximate and ultimate factors driving its evolution remain uncertain. Polymorphic species show variation in behavioural responses to selective forces. Therefore, we estimated effects of various environmental factors (temperature, humidity, food availability, (micro)habitat structure and predatory pressure) on behavioural response (frequency of locomotion, climbing and hiding) of C. nemoralis morphs, in experimental and natural conditions. In the experimental part of study, the frequency of locomotion was negatively affected by temperature and the presence of food and positively influenced by the presence of light. Morphs significantly differed in behavioural responses to environmental variability. Pink mid-banded and yellow five-banded morphs climbed less often and hide in shelter more often than yellow and pink unbanded individuals when temperature was low and food was absent. Snails fed most often at moderate temperature compared to low and high temperatures. Field investigations partially confirmed differences among morphs in frequency of climbing, but not in terms of probability of hiding in sheltered sites. In natural colonies, temperature and (micro)habitat structure significantly affected frequency of climbing as well as hiding in shelter. Snails more often hid in sheltered sites where thrushes preyed on Cepaea. Tendency of unbanded morphs to climb trees may have evolved under avian predatory pressure as thrushes forage on a ground. Tendency of banded morphs to hide in sheltered sites may reflect prey preferences for cryptic background. The results implicate that differential behaviour of C. nemoralis morphs compensate for their morphological and physiological limitations of adaptation to habitat.