Multi-Criteria Assessment of Tensions in Resource Use at Continental Scale: A Proof of Concept with Australian Rangelands

The purpose of this study was to help to inform policy development for the Australian rangelands, and provide a proof of concept for application of a multi-criteria analysis approach to assessment of competing resource use at continental scale. The study aimed to identify and locate key natural resource and agricultural production assets in the rangelands, define a number of measures of potentially threatening processes, and use a multi-criteria approach to identify areas where threatening processes, agricultural production problems, or valuable natural resources coincided. The analysis used 35 readily available, continental spatial data layers at 5-km pixel resolution ranked from 1 (low) to 5 (high) under three themed groupings: natural resource base, production base, and threatening processes. These measures were aggregated into composite indicators to define attributes such as environmental sensitivity and total grazing pressure. The composites were then compared in a two-way analysis to explore particular interactions between threatening processes such as pastoralism and mining, and the condition of production and natural resource assets. These interactions were defined as “tensions” for purposes of this analysis. Example “tensions” included the association of high grazing intensity with areas of high environmental sensitivity, indicating a risk of land degradation under adverse climatic conditions. A summary of patterns of tension was obtained by extracting area proportions of high-tension classes for selected Natural Heritage Trust Regions, which are a basis for Australian Government funding of improved environmental management. The study provides a basis for further examination of trade-offs in the use of natural assets, opportunities for improved productivity and sustainability, and social and economic implications.     

A Constant Erosion Rate Model for Fine Sediment in the York River,Virginia

Results of field experiments using the Virginia Institute of Marine Science' Sea Carousel and tripod system reveal a highly dynamic sediment activity at the Clay Bank site in the York River. At the water-sediment interface, the critical bed shear stress for sediment erosion varied between 0.026 Pa and 0.1 Pa. For the well consolidated sediment below the interface, the critical bed shear stress increased significantly, to more than 0.6 Pa. The seasonal variation of erosion rate for the surficial sediment is significant. For the well consolidated sediment below the surficial sediment, however, the seasonal variation diminished and erosion rate approached a constant. Experimental results from the Carousel deployments imply that the erosion process for quasi-steady tidal flows is always near equilibrium. For this reason, a constant rate erosion model is proposed for the time during tidal acceleration phases. For other times, the erosion rate would be zero. The measured suspended sediment concentration at 10 cm above bed from the VIMS tripod system also Supports this model.     

Brood pheromone stimulates pollen foraging in honey bees (Apis mellifera)

Foraging and the mechanisms that regulate the quantity of food collected are important evolutionary and ecological attributes for all organisms. The decision to collect pollen by honey bee foragers depends on the number of larvae (brood), amount of stored pollen in the colony, as well as forager genotype and available resources in the environment. Here we describe how brood pheromone (whole hexane extracts of larvae) influenced honey bee pollen foraging and test the predictions of two foraging-regulation hypotheses: the indirect or brood-food mechanism and the direct mechanism of pollen-foraging regulation. Hexane extracts of larvae containing brood pheromone stimulated pollen foraging. Colonies were provided with extracts of 1000 larvae (brood pheromone), 1000 larvae (brood), or no brood or pheromone. Colonies with brood pheromone and brood had similar numbers of pollen foragers, while those colonies without brood or pheromone had significantly fewer pollen foragers. The number of pollen foragers increased more than 2.5-fold when colonies were provided with extracts of 2000 larvae as a supplement to the 1000 larvae they already had. Within 1 h of presenting colonies with brood pheromone, pollen foragers responded to the stimulus. The results from this study demonstrate some important aspects of pollen foraging in honey bee colonies: (1) pollen foragers appear to be directly affected by brood pheromone, (2) pollen foraging can be stimulated with brood pheromone in colonies provided with pollen but no larvae, and (3) pollen forager numbers increase with brood pheromone as a supplement to brood without increasing the number of larvae in the colony. These results support the direct-stimulus hypothesis for pollen foraging and do not support the indirect-inhibitor, brood-food hypothesis for pollen-foraging regulation. Received: 5 March 1998 / Accepted after revision: 29 August 1998     

Modeling of road traffic noise and estimated human exposure in Fulton County, Georgia, USA

Environmental noise is a major source of public complaints. Noise in the community causes physical and socio-economic effects and has been shown to be related to adverse health impacts. Noise, however, has not been actively researched in the United States compared with the European Union countries in recent years. In this research, we aimed at modeling road traffic noise and analyzing human exposure in Fulton County, Georgia, United States. We modeled road traffic noise levels using the United States Department of Transportation Federal Highway Administration Traffic Noise Model implemented in SoundPLAN?. After analyzing noise levels with raster, vector and fa?ade maps, we estimated human exposure to high noise levels. Accurate digital elevation models and building heights were derived from Light Detection And Ranging survey datasets and building footprint boundaries. Traffic datasets were collected from the Georgia Department of Transportation and the Atlanta Regional Commission. Noise level simulation was performed with 62 computers in a distributed computing environment. Finally, the noise-exposed population was calculated using geographic information system techniques. Results show that 48% of the total county population [N=870,166 residents] is potentially exposed to 55 dB(A) or higher noise levels during daytime. About 9% of the population is potentially exposed to 67 dB(A) or higher noises. At nighttime, 32% of the population is expected to be exposed to noise levels higher than 50 dB(A). This research shows that large-scale traffic noise estimation is possible with the help of various organizations. We believe that this research is a significant stepping stone for analyzing community health associated with noise exposures in the United States.     

Gasification and its emission characteristics for dried sewage sludge utilizing a fluidized bed gasifier

Various research has attempted to determine the proper treatment of sewage sludge, including thermal technologies. Efficient thermal technologies have been focused on because of their energy saving/energy recovery. Gasification technology can be considered one of these approaches. In this study, the characteristics of gasification reactions were investigated with the aim of finding fundamental data for utilizing sewage sludge as an energy source. For the experiments on sewage sludge gasification reaction characteristics, a laboratory-scale experimental apparatus was set up with a fluidizing bed reactor of 70-mm inner diameter and 600-mm total height using an electric muffle furnace. The experimental materials were prepared from a sewage treatment plant located in Seoul. The reaction temperature was varied from 630 to 860°C, and the equivalence ratio from 0.1 to 0.3. The gas yields, compositions of product gas, and cold gas efficiencies of product gas were analyzed by GC/TCD and GC/FID installed with a carboxen-1000 column. The experimental results indicated that 800°C, ER 0.2 was an optimum condition for sewage sludge gasification. The maximum yield of product gas was about 44%. Producer gas from experiments was mainly composed of hydrogen, carbon monoxide, carbon dioxide, and methane. The cold gas efficiency of sewage sludge gasification was about 68%. The H₂/CO ratio and CO/CO₂ ratio were about 1.1 and 1.4, respectively, in optimum reaction conditions. Gaseous pollutants such as SO₂, HCl, NH₃, H₂S, and NO₂ were also analyzed at various gasification/combustion conditions, and their gaseous products were compared, showing significantly different oxidized product distributions.     

Measured and modelled tritium concentrations in freshwater Barnes mussels (Elliptio complanata) exposed to an abrupt increase in ambient tritium levels

To improve understanding of environmental tritium behaviour, the International Atomic Energy Agency (IAEA) included a Tritium and C-14 Working Group (WG) in its EMRAS (Environmental Modelling for Radiation Safety) program. One scenario considered by the WG involved the prediction of time-dependent tritium concentrations in freshwater mussels that were subjected to an abrupt increase in ambient tritium levels. The experimental data used in the scenario were obtained from a study in which freshwater Barnes mussels (Elliptio complanata) were transplanted from an area with background tritium concentrations to a small Canadian Shield lake that contains elevated tritium. The mussels were then sampled over 88 days, and concentrations of free-water tritium (HTO) and organically-bound tritium (OBT) were measured in the soft tissues to follow the build-up of tritium in the mussels over time.The HTO concentration in the mussels reached steady state with the concentration in lake water within one or two hours. Most models predicted a longer time (up to a few days) to equilibrium. All models under-predicted the OBT concentration in the mussels one hour after transplantation, but over-predicted the rate of OBT formation over the next 24 h. Subsequent dynamics were not well modelled, although all participants predicted OBT concentrations that were within a factor of three of the observation at the end of the study period. The concentration at the final time point was over-predicted by all but one of the models. The relatively low observed concentration at this time was likely due to the loss of OBT by mussels during reproduction.     

Distribution of perfluorochemicals between sera and milk from the same mothers and implications for prenatal and postnatal exposures

The levels of six perfluorocarboxylates (PFCAs), four perfloroalkylsulfonates (PFASs), and one sulfonamide were measured in paired samples of maternal serum, umbilical cord serum, and breast milk. The maternal and cord sera were strongly correlated with each other for all measured compounds (r > 0.5 and p < 0.01). Nevertheless, there was a significant difference in compound composition profile between the two sera matrices, with a more depletion of the longer chain compounds in cord serum. The transfer efficiency values from maternal to cord serum (TF_CS/MS) decreased by 70% with each increasing unit of -CF₂ chain within a PFCA group, and for perfluorooctanesulfonate (PFOS), by a half compared to perfluorooctanoate (PFOA). In contrast to the strong correlation in concentrations between the two sera matrices, the pattern of compounds in breast milk differed considerably with those in sera. Accordingly, compound- and matrix-specific transfer must be considered when assessing prenatal and postnatal exposure.     

Cultural heritage: a potential pollution source in museum

Introduction  

The purposes of this study, as part of research projects for establishing the preservation environment of domestic cultural properties, are to identify the hazardous environmental factors which have a possibility to cause damages on long-term preservation of cultural heritage within the museum exhibition halls and the storages area, and to provide the basic data for the future establishment of preservation environment.     

Fine particle removal performance of a two-stage wet electrostatic precipitator using a nonmetallic pre-charger

A novel two-stage wet electrostatic precipitator (ESP) has been developed using a carbon brush pre-charger and collection plates with a thin water film. The electrical and particle collection performance was evaluated for submicrometer particles smaller than 0.01- 0.5 micrometer in diameter by varying the voltages applied to the pre-charger and collection plates as well as the polarity of the voltage. The collection efficiency was compared with that calculated by the theoretical models. The long-term performances of the ESP with and without water films were also compared in tests using Japanese Industrial Standards dust. The experimental results show that the carbon brush pre-charger of the two-stage wet ESP had approximately 10% particle capture, while producing ozone concentrations of less than 30 ppb. The produced amounts of ozone are significantly lower than the current limits set by international agencies. The ESP also achieved a high collection rate performance, averaging 90% for ultrafine particles, as based on the particle number concentration at an average velocity of 1 m/sec corresponding to a residence time of 0.17 sec. Higher particle collection efficiency for the ESP can be achieved by increasing the voltages applied to the pre-charger and the collection plates. The decreased collection efficiency that occurred during dust loading without water films was completely avoided by forming a thin water film on the collection plates at a water flow rate of 6.5 L/min/m(2).