Jun 2009, Volume 3 Issue 2
    

  • Select all
  • RESEARCH ARTICLE
    M. ?MIETANKA, J. BRZOZOWSKI, D. ?LIWI?SKI, K. SMARZY?SKA, Z. MIATKOWSKI, M. KALARUS

    Poland, like other EU countries, is obliged to implement the Water Framework Directive (2000/60/WE) by the end of 2015. The main objective of the Directive is to provide normative quality of all water resources (surface, underground and coastal sea waters). To reach this goal, reduction of water pollutant emission to the environment is needed. Our project focuses on pollution from agricultural sources which share in global pollution, which is high and growing. This is due to both intensification of agricultural activities and ignoring Agricultural Good Practice Code rules by farmers. In view of the above, this project is expected to provide analysis of selected catchments; especially those exposed to agricultural pollution risk, and propose adjustment strategies for new trends, still keeping in mind environment protection.

    Our project concerns the area further called “sensitive area” (according to the rules of Regional Water Management Board in Warsaw). A part of Zglowiaczka river catchments in central Poland was defined as sensitive area (125.3 km2) where reduction of nitrogen and phosphorus run-off from agricultural land to water resources is especially needed. This is a typical agricultural district characterized by good soil quality (predominance of black swampy soil with deep and fertile humus layers). Due to this, it is the first and foremost high quality agricultural land, and almost forestless. The main topic of the research, with the use of the SWAT model, is to propose different means for reduction of migration of P and N to surface waters. Another problem is retention of water for actual and future irrigations. After model verification, calibration and validation, several climatic changes and reclamation strategies will be tested and simulated by the model to find the most effective and profitable solutions.

    The project focuses on supporting administration and self-governmental organization in the implementation of effective strategies of catchments management based on a modeling approach. This method enables analysis of trends and early warning system against excessive pollution load. Enhancement of the ecological education level and activation of local population for implementation of EU directives are also very important factors.

  • RESEARCH ARTICLE
    Sheng PENG

    Heap leaching is essentially a process in which metals are extracted from mine ores with lixiant. For a better understanding and modeling of this process, solute transport parameters are required to characterize the solute transport system of the leach heap. For porous media like leach ores, which contain substantial gravelly particles and have a broad range of particle size distributions, traditional small-scale laboratory experimental apparatus is not appropriate. In this paper, a 2.44 m long, 0.3 m inner diameter column was used for tracer test with boron as the tracer. Tracer tests were conducted for 2 bulk densities (1.92 and 1.62 g/cm3) and 2 irrigation rates (2 and 5 L/ (m2·h-1)). Inverse modeling with two-region transport model using computer code CXTFIT was conducted based on the measured breakthrough curves to estimate the transport parameters. Fitting was focused on three parameters: dispersion coefficient D, partition coefficient β, and mass transfer coefficient ω. The results turned out to fall within reasonable ranges. Sensitivity analysis was conducted for the three parameters and showed that the order of sensitivity is β>ω>D. In addition, scaling of these parameters was discussed and applied to a real scale heap leach to predict the tracer breakthrough.

  • RESEARCH ARTICLE
    Xiaofen YANG, Hongmei WANG, Linfeng GONG, Hima HASSANE, Zhengbo JIANG

    Fe2+ oxidation by Acidithiobacillus ferrooxidans in pure and mixed cultures was investigated in batch cultures in the presence of arsenate. The pH value was periodically monitored and Fe2+ content was analyzed by the 1,10-phenanthroline method. ICP-AES was employed for the analysis of As(V) concentration in the solution phase. Precipitates were collected and analyzed by X-ray diffraction. Slight enhancement of iron bio-oxidation was observed in mixed cultures with the two greatest As(V) concentrations (1.0 and 5.0 mg/L As), which were enriched from sediment samples in an abandoned copper mine site. As(V) concentrations decreased with time, indicating either the co-precipitation with or the adsorption by jarosite, the major sink of solid phase. Our data suggest that biogenically synthesized jarosite may play an important role in the attenuation of soluble arsenate in natural aquatic environments.

  • RESEARCH ARTICLE
    Fang TIAN, Xianyong CAO, Qinghai XU, Yuecong LI

    Different sedimentary settings can influence preservation of pollens, which would lead to mis-interpretation of fossil pollen spectrum. This study investigates the influence on the preservation of Pinustabulaeformis pollen by simulating alkaline and oxidative environment in the laboratory. There was no obvious change in the content of Pinustabulaeformis pollen while comparing the original with the ones that were immersed with 10% NaOH liquor for ten days, or boiled for five hours, and or boiled with 20%-30% NaOH for one hour, respectively. However, the pollen fossils were obviously corroded and eroded after being boiled with 40% NaOH for one hour and were seriously corroded after five hours. The result indicates that Pinus tabulaeformis pollen is quite durable in alkaline environment and heating condition within a shorter period of time, although alkaline environment has a disadvantage for itspreservation. We also tested the influence of oxidation on Pinus tabulaeformis pollen preservation with KMnO4 as oxidant. The result presents that the number of remaining Pinustabulaeformis pollen grains decreased quickly after being dipped in KMnO4 along with extending the reaction time and reinforcing oxidant. The rate of remnant pollen grains was less than 1% after being dipped with 2% KMnO4 for one hour. It is suggested that oxidative environment has stronger influence on Pinus tabulaeformis pollen preservation than alkaline environment.

  • RESEARCH ARTICLE
    Chengling JIA, Anwen ZHOU, Xiangru MA, Jingjing LI, Shucheng XIE

    The leaves of six plant species and the corresponding leaf residues collected in water from the two-year simulation experiments were analyzed in n-alkane distributions by gas chromatography (GC) and gas chromatography-mas spectrometry (GC/MS). The leaf n-alkanes keep unchanged in the dominant homologues when soaked in tap water for two years. The most significant change was observed in carbon preference index (CPI), with enhanced values being found in leaf residues collected from water. This is contradictory with the previous reports showing the lower CPI values during sinking and burial processes in natural aquatic environments. The elevated CPI values from leaf residues might be related to the low amount of microorganisms in the water used in the simulation experiment, and the enhanced solubility of even-carbon-numbered n-alkanes via van der Waals attraction. In contrast with herbaceous plants, the woody plants appear to show relatively great variations in both the CPI and the average chain length (ACL) values of n-alkanes after submerged in water for two years. Our data clearly show the differentiated decomposition between woody and herbaceous leaves, with the woody leaves suffered from much stronger decomposition. This observation suggests that in comparison with the grassland, the forest vegetation might result in relatively low authentic signals to be preserved in the n-alkane distributions in aquatic sediments.

  • REVIEW ARTICLE
    Lingli WANG, John J. QU

    Surface soil moisture is one of the crucial variables in hydrological processes, which influences the exchange of water and energy fluxes at the land surface/atmosphere interface. Accurate estimate of the spatial and temporal variations of soil moisture is critical for numerous environmental studies. Recent technological advances in satellite remote sensing have shown that soil moisture can be measured by a variety of remote sensing techniques, each with its own strengths and weaknesses. This paper presents a comprehensive review of the progress in remote sensing of soil moisture, with focus on technique approaches for soil moisture estimation from optical, thermal, passive microwave, and active microwave measurements. The physical principles and the status of current retrieval methods are summarized. Limitations existing in current soil moisture estimation algorithms and key issues that have to be addressed in the near future are also discussed.