Fractionation of heavy metals in bottom sediments using Tessier procedure

The study presents the results of Cu, Pb, Zn, Mn and Fe determination in the samples of bottom sediments collected from the Oder and Warta rivers. The sequential extraction of metals in the samples of bottom sediments was performed after introducing the modification of the extraction scheme suggested by Tessier et al. (Anal Chem 51(7):844–851, 1979). The extraction times of particular stages were optimised. The fifth stage was altered by introducing the new methods of performing extraction. The samples of bottom sediments submitted the following granulometric analyses: dry, wet and wet with (HMP) dispersing reagent. Seven granulometric fractions with the following grain sizes were isolated: >2.0, 2.0–1.0, 1.0–0.5, 0.5–0.25, 0.25–0.1, 0.1–0.063 and <0.063 mm. The sequential extraction of particular granulometric fractions was performed. The concentration of metals variability was analysed depending on the method of sample preparation for the chemical analysis, granulometric fraction of sediments subjected to the analysis, extraction conditions and the site of samples collection. The lack of linearity between the metal concentration and the size of granulometric fraction was observed. The highest concentrations of metals were observed in fractions >2.0, 2.0–1.0 and 0.1–0.063 and <0.063 mm while the lowest concentrations occurred in fractions 1.0–0.5, 0.5–0.25, and 0.25–0.1 mm. The atomic absorption spectrometry with flame atomisation (F-AAS) was used for the determination of the investigated elements.     

Saline groundwater seepage zones and their impact on soil and water resources in the Spicers Creek catchment,central west,New South Wales,Australia

Saline seepage zone development and hence dryland salinity is a major environmental problem which many arid to semiarid landscapes in Australia are experiencing. Due to the geological complexity of the regional aquifer system and the heterogeneous nature of the local groundwater system, each groundwater seepage zone in the Spicers Creek catchment, central west, New South Wales, Australia possesses different mechanisms which control its development. Saline seepage zones have formed adjacent to a fault zone, and two experimental sites were established through these groundwater discharge zones to understand geochemical processes which have led to the development of soil sodicity, gully erosion and the flushing of salts into the surface water systems. Seepage zone groundwaters contain a distinctive geochemical signature with elevated concentrations of Na, Cl, HCO₃, Ca, Sr, B, As and Li. The mixing of deep saline groundwaters together with ion exchange processes lead to a distinctive seepage zone groundwater chemistry being developed. Altering the landscape features within this rural groundwater system has developed water toxicity for crops, soil sodicity leading to land degradation, and waterlogging problems.     

Chosen aspects of sustainable development on the Polish, Czech and German borderland

The shift to market forces in Poland, East Germany and Czech Republic has fundamentally reconfigured its economic geography. In particular, spatial inequalities between neighboring Polish, Czech and German border regions have re-emerged forcefully in response to new values, expectations and preferences. In this paper the example of coal mines illustrates the potency of spatial planning. The abundance of coal mines in the Polish, Czech and German borderland at or near abandonment and their proximity to ecological corridors make them candidates for renewed uses in industry or conservation. Attention will also be given to the main environmental problems caused by wrongly conducted spatial policy on this borderland. Transforming a landscape requires continuation of guidance and financial assistance of the European Union.     

Hydrochemical processes in ground water-discharge playas,Central Australia

A large groundwater system in the Amadeus Basin, central Australia, discharges to a chain of playa lakes 500 km long. The playas contain highly concentrated brines; these are sodium-chloride rich waters with appreciable magnesium and sulphate and very low concentrations of calcium and bicarbonate. Gypsum, glauberite, and other evaporite minerals are precipitating in the playas. The groundwaters evolve to brine by concurrent processes of dissolution, evaporative concentration, mineral precipitation, and mineralogical change. Chemical evolution is considered with reference to a concentration factor based on chloride. Ion transfer calculations demonstrate losses of magnesium and bicarbonate throughout, as a result of precipitation. Sodium, potassium, calcium, and sulphate are gained initially as a result of dissolution but lost subsequently as a result of precipitation. Larger playas in the chain, exemplified by Lake Amadeus, have dual shallow and deep groundwater flow paths whereas the smaller playas, exemplified by Spring Lake, have only shallow flow paths. Brines in the larger playas are diluted by deep groundwaters and this is reflected in the degree of saturation attained with respect to particular minerals. Thus, saturation with respect to gypsum and glauberite is attained earlier in Spring Lake than in Lake Amadeus. Saturation with respect to halite is attained in Spring Lake but not in Lake Amadeus. Both playas are undersaturated with respect to hexahydrite and sylvite although these minerals occur in efflorescent crusts in Spring Lake.     

Magneto-telluric recordings from the Friuli seismic zone, northeast Italy

Magneto-telluric measurements were undertaken in the Friuli seismic area of north-east Italy. The purpose was to find possible correlations between magneto-telluric signals and seismic activity. Two stations were operational between July 1987 and June 1988. Apparent resistivity curves were found for September 1987 and January 1988 data, and a magneto-telluric inversion problem was solved. Artificial noise and natural disturbances of the electromagnetic field, especially those related to tectonic processes, are discussed.     

An exact numerical time integration of scalar equations for undamped structural systems

An exact numerical time integration of scalar equations for undamped structural systems is presented. Typical numerical examples are included to illustrate the use of the proposed procedure.     

A generalized least-squares family of algorithms for transient dynamic analysis

By use of the generalized least-squares procedure, in conjunction with a finite element approximation in time, a simple three-time-level family of time integration schemes is derived. This results in fourth-order accurate unconditionally stable algorithms and stable eighth-order accurate non-dissipative algorithms. Numerical examples show the accuracy of the proposed schemes in comparison with the Fox-Goodwin formula and Newmark's average acceleration method.