Sequential extractions of selenium soils from Stewart Lake: total selenium and speciation measurements with ICP-MS detection

Different techniques have been employed in order to evaluate the most efficient procedure for the extraction of selenium from soil as required for speciation. Selenium contaminated sediments from Stewart Lake Wetland, California were used. A strong acid mineralization of the samples gives quantitative total selenium, which is then used to estimate recoveries for the milder extraction methods. The different extraction methodologies involve the sequential use of water, buffer (phosphate, pH 7) and either acid solution (e.g. HNO3 or HCl) or basic solutions (e.g. ammonium acetate, NaOH or TMAH). Pyrophosphate extraction was also evaluated and showed that selenium was not associated with humic acids. The extractants were subsequently analyzed by size exclusion chromatography (SEC) with UV (254 and 400 nm) and on-line ICP-MS detection; anion exchange chromatography, and ion-pair reversed phase chromatography with ICP-MS detection. For sequential extractions the extraction efficiencies showed that the basic extractions were more efficient than the acidic. The difference between the acidic and the basic extraction efficiency is carried to the sulfite extraction, suggesting that whatever is not extracted by the acid is subsequently extracted by the sulfite. The species identified with the different chromatographies were selenate, selenite, elemental selenium and some organic selenium.     

Focusing biodiversity research on the needs of decision makers

The project on Biodiversity Uncertainties and Research Needs (BURN) ensures the advancement of usable knowledge on biodiversity by obtaining input from decision makers on their priority information needs about biodiversity and then using this input to engage leading scientists in designing policy-relevant research. Decision makers articulated concerns related to four issues: significance of biodiversity; status and trends of biodiversity; management for biodiversity; and the linkage of social, cultural, economic, legal, and biological objectives. Leading natural and social scientists then identified the research required to address the decision makers' needs and determined the probability of success. The diverse group of experts reached consensus on several fundamental issues, helping to clarify the role of biodiversity in land and resource management. The BURN participants identified several features that should be incorporated into policy-relevant research plans and management strategies for biodiversity. Research and assessment efforts should be: multidisciplinary and integrative, participatory with stakeholder involvement, hierarchical (multiple scales), and problem- and region-specific. The activities should be focused regionally within a global perspective. Meta-analysis of existing data is needed on all fronts to assess the state of the science. More specifically, the scientists recommended six priority research areas that should be pursued to address the information needs articulated by decision makers: (1) characterization of biodiversity, (2) environmental valuation, (3) management for sustainability—for humans and the environment (adaptive management), (4) information management strategies, (5) governance and stewardship issues, and (6) communication and outreach. Broad recommendations were developed for each research area to provide direction for research planning and resource management strategies. The results will directly benefit those groups that require biodiversity research to address their needs—whether to develop policy, manage natural resources, or make other decisions affecting biodiversity.     

What happened to the Second World? Earthquakes and postsocialism in Kazakhstan

There is an assumption that with the disintegration of the Soviet Union, the Second World ceased to exist. Yet the demise of the Communist bloc as a geopolitical reality did not mean that it stopped exerting a defining influence over how people think and behave. This article examines how the postsocialist state in Kazakhstan deals with potential crises such as earthquakes and the extent to which the Soviet legacy still shapes intellectual debates, state structures, and civil society organisations in in that country. Drawing on fieldwork and interviews, this paper re-examines the Second World in its historical context and re-establishes it as a conceptual framework for considering disaster risk reduction in the former Soviet bloc. It argues that it is essential to pay attention to this legacy in Kazakhstan both in policy and practice if earthquake risk reduction is to be made more effective.     

A study on the reaction characteristics of vanadium-impregnated natural manganese oxide in ammonia selective catalytic reduction

This study investigated the effect of adding vanadium (V) to natural manganese oxide (NMO) in ammonia (NH3) selective catalytic reduction (SCR). The addition of V to NMO decreased the catalytic activity at low temperatures by blocking the active site. However, the enhancement of catalytic activity was achieved by controlling NH3 oxidation at high temperatures. From the NH3 temperature programmed desorption and oxygen on/off test, it was confirmed that the amount of Lewis acid site and active lattice oxygen of the catalyst affects the catalytic performance at low temperature.     

The Control of an Invasive Bivalve, Corbicula fluminea, Using Gas Impermeable Benthic Barriers in a Large Natural Lake

Anoxia can restrict species establishment in aquatic systems and the artificial promotion of these conditions can provide an effective control strategy for invasive molluscs. Low abundances (2-20 m(-2)) of the nonnative bivalve, Asian clam (Corbicula fluminea), were first recorded in Lake Tahoe, CA-NV in 2002 and by 2010 nuisance-level population densities (>10,000 m(-2)) were observed. A non-chemical control method using gas impermeable benthic barriers to reduce dissolved oxygen (DO) concentrations available to C. fluminea was tested in this ultra-oligotrophic natural lake. In 2009, the impact of ethylene propylene diene monomer (EPDM) sheets (9 m(2), n = 6) on C. fluminea beds was tested on 1-7 day intervals over a 56 day period (August-September). At an average water temperature of 18 °C, DO concentrations under these small barriers were reduced to zero after 72 h resulting in 100 % C. fluminea mortality after 28 days. In 2010, a large EPDM barrier (1,950 m(2)) was applied to C. fluminea populations for 120 days (July-November). C. fluminea abundances were reduced over 98 % after barrier removal, and remained significantly reduced (>90 %) 1 year later. Non-target benthic macroinvertebrate abundances were also reduced, with variable taxon-specific recolonization rates. High C. fluminea abundance under anoxic conditions increased the release of ammonium and soluble reactive phosphorus from the sediment substrate; but levels of unionized ammonia were low at 0.004-0.005 mg L(-1). Prolonged exposure to anoxia using benthic barriers can provide an effective short term control strategy for C. fluminea.     

APPLICATION OF GREY MODEL AND ARTIFICIAL NEURAL NETWORKS TO FLOOD FORECASTING1

The main focus of this study was to compare the Grey model and several artificial neural network (ANN) models for real time flood forecasting, including a comparison of the models for various lead times (ranging from one to six hours). For hydrological applications, the Grey model has the advantage that it can easily be used in forecasting without assuming that forecast storm events exhibit the same stochastic characteristics as the storm events themselves. The major advantage of an ANN in rainfall‐runoff modeling is that there is no requirement for any prior assumptions regarding the processes involved. The Grey model and three ANN models were applied to a 2,509 km² watershed in the Republic of Korea to compare the results for real time flood forecasting with from one to six hours of lead time. The fifth‐order Grey model and the ANN models with the optimal network architectures, represented by ANN1004 (34 input nodes, 21 hidden nodes, and 1 output node), ANN1010 (40 input nodes, 25 hidden nodes, and 1 output node), and ANN1004T (14 input nodes, 21 hidden nodes, and 1 output node), were adopted to evaluate the effects of time lags and differences between area mean and point rainfall. The Grey model and the ANN models, which provided reliable forecasts with one to six hours of lead time, were calibrated and their datasets validated. The results showed that the Grey model and the ANN1010 model achieved the highest level of performance in forecasting runoff for one to six lead hours. The ANN model architectures (ANN1004 and ANN1010) that used point rainfall data performed better than the model that used mean rainfall data (ANN1004T) in the real time forecasting. The selected models thus appear to be a useful tool for flood forecasting in Korea.     

Validation of the propensity for angry driving scale

Problem: This study examined the validity of the Propensity for Angry Driving Scale (PADS; DePasquale, J. P., Geller, E. S., Clarke, S. W., and Littleton, L. C. (2001). Measuring road rage: Development of the Propensity for Angry Driving Scale. Journal of Safety Research, 32, 1–16) in predicting aggressive driving. Method: The PADS and the Driving Anger Scale (DAS; Deffenbacher, J. L., Oetting, E. R., and Lynch, R. S. (1994). Development of a driving anger scale. Psychological reports, 74, 83–91.) were administered to 232 college student volunteers with measures of aggressive and risky driving. Results: Convergent and discriminant validity of the PADS were supported through relationships among measures of similar constructs. The PADS significantly (p<.05) predicted moving tickets, minor accidents, aggressive driving, risky driving, and maladaptive driving anger expression, above and beyond gender, miles driven per week, and trait anger. Discussion: Findings suggest that the PADS is a useful predictor of aggressive driving and has some advantages over the DAS. Impact on Industry: The PADS is an effective predictor of aggressive driving that complements established measures like the DAS and provides researchers with another valuable tool for the assessment of aggressive driving.     

A framework for assessing the sustainability of brownfield developments

In England, the development of urban brownfield sites is a significant planning policy aimed at supporting urban regeneration and protecting the countryside. Brownfield sites are required, in policy, to be developed in a sustainable way. However, determining what this means in practice is unclear. This paper presents a framework for assessing the sustainability of brownfield developments, devised to clarify the stakeholders in land reuse and establish how sustainability can be achieved on reused sites. The framework has been used in research investigating the sustainability of five brownfield developments in England. The performance of the framework in this research is assessed and its potential practical use outlined.     

Estimation of mass transport parameters of gases for quantifying CH4 oxidation in landfill soil covers

Methane (CH(4)), which is one of the most abundant anthropogenic greenhouse gases, is produced from landfills. CH(4) is biologically oxidized to carbon dioxide, which has a lower global warming potential than methane, when it passes through a cover soil. In order to quantify the amount of CH(4) oxidized in a landfill cover soil, a soil column test, a diffusion cell test, and a mathematical model analysis were carried out. In the column test, maximum oxidation rates of CH(4) (V(max)) showed higher values in the upper part of the column than those in the lower part caused by the penetration of O(2) from the top. The organic matter content in the upper area was also higher due to the active microbial growth. The dispersion analysis results for O(2) and CH(4) in the column are counter-intuitive. As the upward flow rate of the landfill gas increased, the dispersion coefficient of CH(4) slightly increased, possibly due to the effect of mechanical dispersion. On the other hand, as the upward flow rate of the landfill gas increased, the dispersion coefficient of O(2) decreased. It is possible that the diffusion of gases in porous media is influenced by the counter-directional flow rate. Further analysis of other gases in the column, N(2) and CO(2), may be required to support this hypothesis, but in this paper we propose the possibility that the simulations using the diffusion coefficient of O(2) under the natural condition may overestimate the penetration of O(2) into the soil cover layer and consequently overestimate the oxidation of CH(4).