A direct passive method for measuring water and contaminant fluxes in porous media

This paper introduces a new direct method for measuring water and contaminant fluxes in porous media. The method uses a passive flux meter (PFM), which is essentially a self-contained permeable unit properly sized to fit tightly in a screened well or boring. The meter is designed to accommodate a mixed medium of hydrophobic and/or hydrophilic permeable sorbents, which retain dissolved organic/inorganic contaminants present in the groundwater flowing passively through the meter. The contaminant mass intercepted and retained on the sorbent is used to quantify cumulative contaminant mass flux. The sorptive matrix is also impregnated with known amounts of one or more water soluble 'resident tracers'. These tracers are displaced from the sorbent at rates proportional to the groundwater flux; hence, in the current meter design, the resident tracers are used to quantify cumulative groundwater flux. Theory is presented and quantitative tools are developed to interpret the water flux from tracers possessing linear and nonlinear elution profiles. The same theory is extended to derive functional relationships useful for quantifying cumulative contaminant mass flux. To validate theory and demonstrate the passive flux meter, results of multiple box-aquifer experiments are presented and discussed. From these experiments, it is seen that accurate water flux measurements are obtained when the tracer used in calculations resides in the meter at levels representing 20 to 70 percent of the initial condition. 2,4-Dimethyl-3-pentanol (DMP) is used as a surrogate groundwater contaminant in the box aquifer experiments. Cumulative DMP fluxes are measured within 5% of known fluxes. The accuracy of these estimates generally increases with the total volume of water intercepted.     

Structural change and environmental impact: Empirical evidence on thirty-one countries in east and west

Although structural change in many industralized countries has increased since the early 1970s, the environmental policy aspects of this change have hardly been investigated. The more pronounced the positive environmental effects of structural change become, the more positive will be the structure-oriented options of environmental policy.Using a set of four indicators, in this study thirty-one Eastern and Western industrialized countries are being tested with regard to economic structure and environmentally significant structural change. The authors come to the conclusion that the strong correlation between economic performance and environmental pollution, unequivocal in 1970, had become much weaker by 1985. The de-linking of economic growth from material-intensive industrial production processes is particularly evident. In some cases automatic environmental benefits (environmental gratis effects) were generated in this way.However, the development profiles of the countries investigated differ greatly. There are countries, in particular Sweden, with absolute structural improvement in the ecological sense; countries like Japan and Norway with structural improvement relative to economic growth; and countries, including most Eastern and Southern European states, featuring no structural improvement or even environmentally negative structural change.The question is being left open to what extent the modernized economic structures are accompanied by modernized forms of environmental pollution.     

Linkages between the energy and agricultural sectors: insights from European Union greenhouse gas mitigation scenarios

Over the past decade, the relationship between agricultural and energy markets has strengthened. Traditional energy sources have been increasingly replaced by energy from biomass, and this trend is expected to continue into the future. Consequently, an assessment of the efficiency of bioenergy policies requires a comprehensive analysis of both agricultural and energy markets. The objective of this paper is to analyze the impacts of two detailed European Union (EU) greenhouse gas (GHG) emission mitigation policies on the utilization of biomass for energy production and the implications for agricultural prices and trade. The consequences of a policy-induced shift from consumption of fossil to renewable energy are assessed under full consideration of interrelations between the energy and agricultural sectors. To this end, we combine an energy system model and an agricultural sector model by establishing a consistent interface between them. Depending on the ambition of the GHG emission reduction scenarios, the results indicate significant price increases. Furthermore, the increase in European demand for energy crops is to a substantial degree covered by additional imports. These results highlight that GHG emission mitigation policies enacted in a large economy like the EU cannot be considered without accounting for indirect effects in the rest of the world. They put the efficiency and also the effectiveness of such policies in general into question.     

Urban sediment contamination in a former Hg mining district,Idrija, Slovenia

Road sediments from gully pots of the drainage system and stream sediments from local streams were investigated for the first time in the urban area of Idrija town, the central part of the second largest and strongly contaminated Hg mining district in the world. Hg concentrations in road sediments were lower than in stream sediments. They ranged from 16 to 110 mg/kg (Md = 29 mg/kg) for <0.125 mm particles and from 7 to 125 mg/kg (Md = 35 mg/kg) for <0.04 mm particles, while Hg concentrations in stream sediments ranged from 10 to 610 mg/kg (Md = 95 mg/kg) for <0.125 particles and from 10 to 440 mg/kg (Md = 105 mg/kg) for <0.04 mm particles. High Hg loadings in stream sediments were successfully linked with identified mercury sources (rocks containing mercury ore, areas of former ore roasting sites, ore residue dumps), because they are located in the drainage areas of streams, from which the sediments were collected. Links between Hg loadings in road sediments and identified mercury sources were not recognized. Solid phases of Hg were determined by thermo-desorption technique and are similar for both types of sediments. Results show the occurrence of three different forms: elemental mercury, mercury bound to matrix components and cinnabar. Approximately 50 % of Hg in samples consist of non-cinnabar fractions. This is important, since they are potentially bioavailable. An interesting new discovery according to previous research of environmental media from Idrija area by solid-phase Hg thermo-desorption technique is that elemental mercury was determined in almost all investigated sediments in minor amounts (Md = 3 %).     

An overview of flood mitigation strategy and research support in South Asia: implications for sustainable flood risk management

South Asia faces increasing flooding risks due to climatic and socio-economic changes. Various measures have been adopted by the governments of the countries in this region. However, these measures are not adequate to protect the vulnerable communities from ever-increasing flood losses. This study assesses the policy and planning processes and flood-related scientific research in India, Pakistan and Bangladesh. Based on a systematic review, a comparison of the existing flood management systems of the three countries is undertaken, and a framework for sustainable flood management in the region is suggested. Insights from the literature show that Bangladesh has been able to develop an effective governance structure to address flood hazards, while Pakistan’s approach to flood management planning is found to be largely inadequate. This inadequacy is mainly attributed to missing links in policy formulation and planning processes, along with a lack of institutional coordination. The results of the literature analysis reveal poor support from scientific research focusing on flooding issues in the case of Pakistan, while Bangladesh and India seem to have benefited from research support in formulating their flood management strategies. Based on these findings, an alternative framework is suggested, emphasizing the need to enhance institutional linkages, community participation and evidence-based research.     

Seed predation by Neotropical rain forest mammals increases diversity in seedling recruitment

Seed dispersal and seedling recruitment (the transition of seeds to seedlings) set the spatiotemporal distribution of new individuals in plant communities. Many terrestrial rain forest mammals consume post-dispersal seeds and seedlings, often inflicting density-dependent mortality. In part because of density-dependent mortality, diversity often increases during seedling recruitment, making it a critical stage for species coexistence. We determined how mammalian predators, adult tree abundance, and seed mass interact to affect seedling recruitment in a western Amazonian rain forest. We used exclosures that were selectively permeable to three size classes of mammals: mice and spiny rats (weighing <1 kg), medium-sized rodents (1-12 kg), and large mammals (20-200 kg). Into each exclosure, we placed seeds of 13 tree species and one canopy liana, which varied by an order of magnitude in adult abundance and seed mass. We followed the fates of the seeds and resulting seedlings for at least 17 months. We assessed the effect of each mammalian size class on seed survival, seedling survival and growth, and the density and diversity of the seedlings that survived to the end of the experiment. Surprisingly, large mammals had no detectable effect at any stage of seedling recruitment. In contrast, small- and medium-sized mammals significantly reduced seed survival, seedling survival, and seedling density. Furthermore, predation by small mammals increased species richness on a per-stem basis. This increase in diversity resulted from their disproportionately intense predation on common species and large-seeded species. Small mammals thereby generated a rare-species advantage in seedling recruitment, the critical ingredient for frequency dependence. Predation by small (and to a lesser extent, medium-sized) mammals on seeds and seedlings significantly increases tree species diversity in tropical forests. This is the first long-term study to dissect the effects of various mammalian predators on the recruitment of a diverse set of tree species.     

A Comparison of Biomonitoring Methods for the Estimation of Atmospheric Pollutants in an Industrial Town in Austria

In the period between 1999 and 2000 epiphytic bryophytes were taken as bioindicators for air pollution by use of the IAP method (Index of Atmospheric Purity) and the VDI method within the Association of Engineers standards list (adapted from guideline 3799, 1995) in the heavy industrialized town of Linz, Austria. 52 study sites (265 trees) were analysed regarding species richness, coverage, and vitality. Q-values (sensitivity factors), calculated for each species showed significant differences for the various host tree species. The results gained by the IAP and the VDI methods were diverse, regarding the various sites where only 25% were classified identical. These differences can mainly be attributed to the differing host tree species and the size of the recording area on the various trees. Clusters of similar pollution levels were calculated and drawn as maps for both methods tested. Comparing the results of the IAP and the VDI methods with data derived from technical measurements (SO₂, NO, NO₂, and dust) a correlation between IAP-indices and SO₂ concentrations could be observed. No correlation was detected between the results derived from VDI recording and for NO, NO₂, and dust.     

On the consequences of aggregation and balancing of networks on system properties derived from ecological network analysis

In the ecological network analysis (ENA) of complex flow food webs the assumption is often made that the models characterizing the flows and stocks of ecosystems occur in a steady state where inflows equals outflows. An assessment of the system indices derived from ENA of six balanced and unbalanced system models, respectively, indicate to differences between indices. The aggregation of highly articulated flow models into models with fewer compartments also has drastic effects on the system metrics, particularly on the information indices.