Teaching industrial ecology and environmental management in Second Life

Second Life is a virtual, open-access, and user-generated environment that has served as a platform for hosting everything from rock concerts to scientific conferences. Many institutions have also used Second Life as an educational tool, for example by, showcasing scientific exhibits or embedding video and images for learning purposes. Here we discuss the creation and use of an interactive, virtual industrial facility - the Elihu Paper Company - as a way to complement a traditional facility tours in a course in industrial environmental management. Virtual facilities offer a number of educational advantages over real-life ones: they are always open and available for tours, they can be accessed instantaneously from anywhere where there is an adequate internet connection, and most importantly, tours and embedded information can be tailored to specific educational objectives. Our experience in using Elihu Paper as a formal facility visit for the past several years shows that students had significantly more time than usual to ask questions, could and did explore the facility independently, and were still able to produce facility reports that fulfilled the educational objectives of the visits, including mapping material flows and explaining pollution prevention and sustainability opportunities.     

A thermodynamic model of freshwater Antarctic lake ice

Antarctic lakes with simple plankton ecosystems are believed to be sensitive biological indicators of climate change. Models of the physical environment, in particular the ice layer, support understanding of how the ecosystems respond to meteorological variables. This paper describes how data from a previously reported automatic measuring probe and meteorological data from Davis station were used to develop a detailed thermodynamic model of the ice layer on Crooked Lake, one of the largest and deepest freshwater lakes in Antarctica. The general model structure is similar to a previously reported model of sea ice but with modifications specific to the Antarctic freshwater lake case informed by the data. The model inputs are atmospheric variables as well as water temperature, ice albedo and the radiation extinction coefficient for the ice. Heat and radiation fluxes at the ice–air and ice–water boundaries are calculated using equations chosen for their suitability for the Antarctic. In the case of shortwave radiation, equations were fitted to data from the automatic probe. Using the heat fluxes to establish boundary conditions, and incorporating the known thermodynamic properties of ice, the temperature profile within the ice and the resulting growth and melt of the ice can be calculated. The model uses a largely mechanistic approach, with most equations taken from established thermodynamic theories or empirical studies and only one adjustable parameter related to the sensible heat flux from the water, which is not easily calculated from the available data. It was found to accurately reproduce ice temperature and ice thickness data for the year 2003, with r² = 0.89, n = 2005. Finally, the model was simplified to run with air temperature as the only input variable and was shown to perform well—this suggests that freshwater lake ice is affected more by air temperature than any other variable, and is therefore a useful indicator of climate change in its own right.     

Understanding abundance patterns of a declining seabird: implications for monitoring.

The Kittlitz's Murrelet (Brachyramphus brevirostris) is a rare, non-colonial seabird often associated with tidewater glaciers and a recent candidate for listing under the Endangered Species Act. We estimated abundance of Kittlitz's Murrelets across space and time from at-sea surveys along the coast of Alaska (USA) and then used these data to develop spatial models to describe abundance patterns and identify environmental factors affecting abundance. Over a five-week period in the summer of 2005, we recorded 794 Kittlitz's Murrelets, 16 Marbled Murrelets (B. marmoratus), and 70 unidentified murrelets. The overall population estimate (N, mean +/- SE) during the peak period (3-9 July) was 1317 +/- 294 birds, decreasing to 68 +/- 37 by the last survey period (31 July-6 August). Density of Kittlitz's Murrelets was highest in pelagic waters of Taan Fjord (18.6 +/- 7.8 birds/km2, mean +/- SE) during 10-16 July. Spatial models identified consistent "hotspots" of Kittlitz's Murrelets, including several small areas where high densities of murrelets were found throughout the survey period. Of the explanatory variables that we evaluated, tidal current strength influenced murrelet abundance most consistently, with higher abundance associated with strong tidal currents. Simulations based on the empirically derived estimates of variation demonstrated that spatial variation strongly influenced power to detect trend, although power changed little across the threefold difference in the coefficient of variation on detection probability. We include recommendations for monitoring Kittlitz's Murrelets (or other marine species) when there is a high degree of uncertainty about factors affecting abundance, especially spatial variability.     

Mathematical modelling of the composting process: a review

In this paper mathematical models of the composting process are examined and their performance evaluated. Mathematical models of the composting process have been derived from both energy and mass balance considerations, with solutions typically derived in time, and in some cases, spatially. Both lumped and distributed parameter models have been reported, with lumped parameter models presently predominating in the literature. Biological energy production functions within the models included first-order, Monod-type or empirical expressions, and these have predicted volatile solids degradation, oxygen consumption or carbon dioxide production, with heat generation derived using heat quotient factors. Rate coefficient correction functions for temperature, moisture, oxygen and/or free air space have been incorporated in a number of the first-order and Monod-type expressions. The most successful models in predicting temperature profiles were those which incorporated either empirical kinetic expressions for volatile solids degradation or CO2 production, or which utilised a first-order model for volatile solids degradation, with empirical corrections for temperature and moisture variations. Models incorporating Monod-type kinetic expressions were less successful. No models were able to predict maximum, average and peak temperatures to within criteria of 5, 2 and 2 degrees C, respectively, or to predict the times to reach peak temperatures to within 8 h. Limitations included the modelling of forced aeration systems only and the generation of temperature validation data for relatively short time periods in relation to those used in full-scale composting practice. Moisture and solids profiles were well predicted by two models, but oxygen and carbon dioxide profiles were generally poorly modelled. Further research to obtain more extensive substrate degradation data, develop improved first-order biological heat production models, investigate mechanistically-based moisture correction factors, explore the role of moisture tension, investigate model performance over thermophilic composting time periods, provide more information on model sensitivity and incorporate natural ventilation aeration expressions into composting process models, is suggested.     

Comparative DFT study of inner-sphere As(III) complexes on hydrated α-Fe2O3(0001) surface models

The long-recognized risk to human health arising from arsenic-contaminated waters is known to be linked to partitioning reactions between arsenic and natural solid phases. Currently, the ability to predict As surface complexation is limited by the lack of molecular-level understanding of As-solid interactions. In the present study, we use density functional theory (DFT) to model mono-, bi-, and tri-dentate As(III) surface complexes on different (previously proposed) structural models for hydrated hematite, modeled as α-Fe(2)O(3)(0001)-water interfaces. One of the modeled hematite-water interfaces is terminated entirely by hydroxyl surface functional groups, comprised of hematite lattice oxygen atoms. The other hematite-water interface is an iron-terminated model in which the outermost oxygen functional groups are water (and water dissociation product) ligands. We report the DFT trends in adsorption energies in terms of As-hematite coordination, hematite surface geometry/stoichiometry, and oxygen functional group identity. The DFT energetics predict that a monodentate As(III) surface complex is preferred on both hematite-water structures, suggesting that the two structural models here employed do not sufficiently represent the true surface structure to reproduce the experimental observation of As(III) bidentate coordination. However, the results do elucidate fundamental concepts of interface reactivity: A key result, supported by electronic structure analysis, is that ligand oxygen functional groups cannot be treated on equal ground with true surface oxygen functional groups. For the systems modeled here the distinction between surface and ligand functional groups supersedes the differences in oxygen coordination with surface Fe. We discuss the impact of this finding on the application of bond-valence-based predictions of mineral-water reactivity, and use the results of this study to pose questions and directions for ongoing modeling efforts aimed at linking macroscopic reactivity with molecular-level understanding.     

From Policy to Practice: Challenges in Infant Feeding in Emergencies During the Balkan Crisis

The preparation and dissemination of policy statements are necessary but insufficient to prevent the inappropriate use of infant-feeding products in emergencies. The widespread failure of humanitarian agencies operating in the Balkan crisis to act in accordance with international policies and recommendations provides a recent example of the failure to translate infant-feeding policies into practice. This article explores the underlying reasons behind the failures which include: (1) the weak institutionalisation of policies; (2) the massive quantities of unsolicited donations of infant-feeding products: (3) the absence of monitoring systems; (4) inadequate co-ordination mechanisms; (5) the high costs of correcting mistakes; and (6) the cumulative effects of poor practice. Efforts to uphold best practice during the crisis are also documented. Finally, the article identifies actions that could be undertaken in advance of and during future emergencies to enhance the application of infant feeding policies in emergencies.     

A case study of potential human health impacts from petroleum coke transfer facilities

Petroleum coke or “petcoke” is a solid material created during petroleum refinement and is distributed via transfer facilities that may be located in densely populated areas. The health impacts from petcoke exposure to residents living in proximity to such facilities were evaluated for a petcoke transfer facilities located in Chicago, Illinois. Site-specific, margin of safety (MOS) and margin of exposure (MOE) analyses were conducted using estimated airborne and dermal exposures. The exposure assessment was based on a combined measurement and modeling program that included multiyear on-site air monitoring, air dispersion modeling, and analyses of soil and surfaces in residential areas adjacent to two petcoke transfer facilities located in industrial areas. Airborne particulate matter less than 10 microns (PM₁₀) were used as a marker for petcoke. Based on daily fence line monitoring, the average daily PM₁₀ concentration at the KCBX Terminals measured on-site was 32 μg/m³, with 89% of 24-hr average PM₁₀ concentrations below 50 μg/m³ and 99% below 100 μg/m³. A dispersion model estimated that the emission sources at the KCBX Terminals produced peak PM₁₀ levels attributed to the petcoke facility at the most highly impacted residence of 11 μg/m³ on an annual average basis and 54 μg/m³ on 24-hr average basis. Chemical indicators of petcoke in soil and surface samples collected from residential neighborhoods adjacent to the facilities were equivalent to levels in corresponding samples collected at reference locations elsewhere in Chicago, a finding that is consistent with limited potential for off-site exposure indicated by the fence line monitoring and air dispersion modeling. The MOE based upon dispersion model estimates ranged from 800 to 900 for potential inhalation, the primary route of concern for particulate matter. This indicates a low likelihood of adverse health effects in the surrounding community.?Implications: Handling of petroleum coke at bulk material transfer facilities has been identified as a concern for the public health of surrounding populations. The current assessment, based on measurements and modeling of two facilities located in a densely populated urban area, indicates that petcoke transport and accumulation in off-site locations is minimal. In addition, estimated human exposures, if any, are well below levels that could be anticipated to produce adverse health effects in the general population.     

Dissipation and sorption of six commonly used pesticides in two contrasting soils of New Zealand

We investigated dissipation and sorption of atrazine, terbuthylazine, bromacil, diazinon, hexazinone and procymidone in two contrasting New Zealand soils (0–10 cm and 40–50 cm) under controlled laboratory conditions. The six pesticides showed marked differences in their degradation rates in both top- and subsoils, and the estimated DT₅₀ values for the compounds were: 19–120 (atrazine), 10–36 (terbuthylazine), 12–46 (bromacil), 7–25 (diazinon), 8–92 (hexazinone) and 13–60 days for procymidone. Diazinon had the lowest range for DT₅₀ values, while bromacil and hexazinone gave the highest DT₅₀ values under any given condition on any soil type. Batch derived effective distribution coefficient (K _d ^eff) values for the pesticides varied markedly with bromacil and hexazinone exhibiting low sorption affinity for the soils at either depth, while diazinon gave high sorption values. Comparison of pesticide degradation in sterile and non-sterile soils suggests that microbial degradation was the major dissipation pathway for all six compounds, although little influence of abiotic degradation was noticeable for diazinon and procymidone.