Influence of cosolvents on quinoline sorption by subsurface materials and clays

Quinoline sorption was measured on Na-saturated subsurface materials, a natural clay isolate, and montmorillonite, and was dominated by exchange of the quinolinium ion. In water/methanol and water/acetone mixtures, quinoline sorption on the subsoils and clays was lower than from water. In cosolvent, sorption followed the ionization fraction indicating the continued predominance of ion exchange. The reduction in quinoline sorption by cosolvent was similar for all the subsoils and clays indicating commonality in the surface-solute-solvent interaction. Conditional equilibrium constants (_cK_ex) for quinoline exchange on the subsoils in water/methanol mixtures decreased log-linearly with mole percent cosolvent up to 20% methanol. This decrease closely followed the increase in quinoline solubility in the cosolvent mixtures. Acetone caused greater reduction in sorption than methanol, at comparable mole percent, in accordance with its lower dielectric constant and enhanced solvating power. A generalized thermodynamic approach based on the concept of transfer activity coefficients was developed to account for the cosolvent effect on _cK_ex, and was successfully applied to the quinoline sorption data. The thermodynamic analysis suggested that enhanced solvation of the organic cation in the bulk solvent and desolvation of Na⁺ at the charged surface predominate the cosolvent effect.     

Government and biodiversity governance in Post-Soviet Azerbaijan: an institutional perspective

Over the last 15 years, Azerbaijan has doubled its protected areas territory to almost 10 % of the country’s surface area. Although the daily management of the existing strictly protected areas continues to pose a challenge, the establishment of nine national parks has been a remarkable achievement. At present, the designation of UNESCO biosphere reserves (BR) is the expressed political will of the government. By reviewing the last 25 years of nature conservation, and, in particular, the national park programme, we present an institutional analysis for integrative nature conservation in Azerbaijan. Against the cultural, social and political background, in particular the transition of the state, the challenges for cross-hierarchical governance of protected areas are outlined at the example of a BR. We find that the implementation of the UNESCO MAB philosophy, which is based on inter alia participation by administration, local communities and rural stakeholder, is hampered by this present-day political reality. The political situation and an autocratic governance scheme put successful implementation of a “model region of sustainable development” at risk. Education and empowerment are a prerequisite for eventual success; this is true for Azerbaijan as well as for other Post-Soviet countries with strong top-down regimes.     

Transitions in high-Arctic vegetation growth patterns and ecosystem productivity tracked with automated cameras from 2000 to 2013

Climate-induced changes in vegetation phenology at northern latitudes are still poorly understood. Continued monitoring and research are therefore needed to improve the understanding of abiotic drivers. Here we used 14 years of time lapse imagery and climate data from high-Arctic Northeast Greenland to assess the seasonal response of a dwarf shrub heath, grassland, and fen, to inter-annual variation in snow-cover, soil moisture, and air and soil temperatures. A late snow melt and start of growing season is counterbalanced by a fast greenup and a tendency to higher peak greenness values. Snow water equivalents and soil moisture explained up to 77 % of growing season duration and senescence phase, highlighting that water availability is a prominent driver in the heath site, rather than temperatures. We found a significant advance in the start of spring by 10 days and in the end of fall by 11 days, resulting in an unchanged growing season length. Vegetation greenness, derived from the imagery, was correlated to primary productivity, showing that the imagery holds valuable information on vegetation productivity.     

Evaluating coal tar-water partitioning coefficient estimation methods and solute-solvent molecular interactions in tar phase

Equilibrium partitioning coefficients between an industrial coal tar sample and water (K(CT/w)) were determined for 41 polar and nonpolar solutes in batch systems. Together with literature values, 69 K(CT/w) data were analyzed using the following model approaches: Raoult's law, the single parameter linear free energy relationship (SPLFER) with octanol-water partitioning coefficients (K(ow)), the linear solvation energy relationships (LSERs), SPARC and COSMOtherm. Estimations by Raoult's law and the SPLFER agreed well with the experimental log K(CT/w) values for the investigated coal tar, with root mean square errors (RMSE) of 0.31 and 0.33, respectively. LSER resulted in as good estimations (RMSE=0.29) as the previous two. The LSER analysis revealed significant hydrogen (H)-bond acceptor properties of the studied coal tar phase. Using naphthalene as a surrogate solvent for the coal tar phase, SPARC and COSMOtherm provided fairly good predictions (RMSE of 0.63 and 0.65, respectively) of log K(CT/w), without any additional empirical parameter. Further calculations using SPARC and COSMOtherm for partitioning between water and other tar-components (e.g., benzofuran, phenol and quinoline) suggested that minor components in coal tar do not significantly influence K(CT/w) of nonpolar solutes, and that Raoult's law and the SPLFER thus may be generally applied to these types of solutes, e.g., polycyclic aromatic hydrocarbons and alkylbenzenes, regardless of coal tar compositions. In contrast, partitioning of H-bonding solutes (e.g., phenols) can significantly vary depending on the amount of polar tar-components such as N-heterocyclic aromatic compounds. Therefore, the presented successful applications of Raoult's law and SPLFER to the studied coal tar could be a special case, and these simple approaches may not provide reasonable estimations for partitioning of H-bonding solutes from compositionally different coal tars.     

Involvement of siderophores in the reduction of metal-induced inhibition of auxin synthesis in Streptomyces spp

Unlike synthetic metal chelators, microbe-assisted phytoremediation provides plants with natural metal-solubilizing chelators which do not constitute a potential source of environmental pollution. Concurrently with microbial chelators, plant growth promotion can be enhanced through bacterially-produced phytohormones. In this work, the simultaneous production of siderophores and auxins by Streptomyces was studied to gain insight for future application in plant growth and phytoremediation in a metal-contaminated soil. Standard auxin and siderophore detection assays indicated that all of the investigated Streptomyces strains can produce these metabolites simultaneously. However, Al(3+), Cd(2+), Cu(2+), Fe(3+) and Ni(2+), or a combination of Fe(3+) and Cd(2+), and Fe(3+) and Ni(2+) affected auxin production negatively, as revealed by spectrophotometry and gas chromatography-mass spectrometry. This effect was more dramatic in a siderophore-deficient mutant. In contrast, except for Fe, all the metals stimulated siderophore production. Mass spectrometry showed that siderophore and auxin-containing supernatants from a representative Streptomyces species contain three different hydroxamate siderophores, revealing the individual binding responses of these siderophores to Cd(2+) and Ni(2+), and thus, showing their auxin-stimulating effects. We conclude that siderophores promote auxin synthesis in the presence of Al(3+), Cd(2+), Cu(2+) and Ni(2+) by chelating these metals. Chelation makes the metals less able to inhibit the synthesis of auxins, and potentially increases the plant growth-promoting effects of auxins, which in turn enhances the phytoremediation potential of plants.     

Erfolgreiche Workshoptagung des VG?D in Potsdam

Ohne Zusammenfassung     

Bestimmung von Mineralölkohlenwasserstoffen in Bodenproben mit Hilfe der Dünnschichtchromatographie

A thin-layer chromatographic method for the determination of mineral oil hydrocarbons (aliphatic compounds and naphtenes) of medium and low volatility in soil samples is presented which is based on their separation and quantitative determination. The extraction of the soil samples is effected by means of an n-hexane-acetone mixture (10∶1) supported by ultrasonics. The evaluation can be made visually or densitometrically by means of a thin-layer scanner. The applicability and restrictions of the method are shown. The advantage of the method lies in its low requirements pertaining to apparatus and chemicals, as well as in its rapidness which makes it suitable for quick in-situ analyses as, for example, for the assessment of the mineral oil content of a contaminated site.     

Multicompartmental fate of persistent substances

Background, Aim and Scope Modelling of the fate of environmental chemicals can be done by relatively simple multi-media box models or using complex atmospheric transport models. It was the aim of this work to compare the results obtained for both types of models using a small set of non-ionic and non-polar or moderately polar organic chemicals, known to be distributed over long distances. Materials and Methods Predictions of multimedia exposure models of different types, namely three multimedia mass-balance box models (MBMs), two in the steady state and one in the non-steady state mode, and one non-steady state multicompartment chemistry-atmospheric transport model (MCTM), are compared for the first time. The models used are SimpleBox, Chemrange, the MPI-MBM and the MPI-MCTM. The target parameters addressed are compartmental distributions (i.e. mass fractions in the compartments), overall environmental residence time (i.e. overall persistence and eventually including other final sinks, such as loss to the deep sea) and a measure for the long-range transport potential. These are derived for atrazine, benz-[a]-pyrene, DDT, α and γ-hexachlorocyclohexane, methyl parathion and various modes of substance entry into the model world. Results and Discussion Compartmental distributions in steady state were compared. Steady state needed 2–10 years to be established in the MCTM. The highest fraction of the substances in air is predicted by the MCTM. Accordingly, the other models predict longer substance persistence in most cases. The results suggest that temperature affects the compartmental distribution more in the box models, while it is only one among many climate factors acting in the transport model. The representation of final sinks in the models, e.g. burial in the sediment, is key for model-based compartmental distribution and persistence predictions. There is a tendency of MBMs to overestimate substance sinks in air and to underestimate atmospheric transport velocity as a consequence of the neglection of the temporal and spatial variabilities of these parameters. Therefore, the long-range transport potential in air derived from MCTM simulations exceeds the one from Chemrange in most cases and least for substances which undergo slow degradation in air. Conclusions and Perspectives MBMs should be improved such as to ascertain that the significance of the atmosphere for the multicompartmental cycling is not systematically underestimated. Both types of models should be improved such as to cover degradation in air in the particle-bound state and transport via ocean currents. A detailed understanding of the deviations observed in this work and elsewhere should be gained and multimedia fate box models could then be ‘tuned in’ to match better the results of comprehensive multicompartmental transport models. ESS-Submission Editor: Prof. Dr. Michael Matthies (matthies@uos.de)     

Life cycle assessment of the waste hierarchy--a Danish case study on waste paper

The waste hierarchy is being widely discussed these days, not only by cost-benefit analysts, but a growing number of life cycle assessments (LCA) have also begun to question it. In this article, we investigate the handling of waste paper in Denmark and compare the present situation with scenarios of more waste being recycled, incinerated or consigned to landfill. The investigations are made in accordance with ISO 14040-43 and based on the newly launched methodology of consequential LCA and following the recent guidelines of the European Centre on Waste and Material Flows. The LCA concerns the Danish consumption of paper in 1999, totalling 1.2 million tons. The results of the investigation indicate that the waste hierarchy is reliable; from an environmental point of view recycling of paper is better than incineration and landfilling. For incineration, the reason for the advantage of landfilling mainly comes from the substitution of fossil fuels, when incinerators provide heat and electricity. For recycling, the advantage is related to the saved wood resources, which can be used for generating energy from wood, i.e., from renewable fuel which does not contribute to global warming.