Modified Fenton's processes for effective in‐situ chemical oxidation—Laboratory and field evaluation

Fenton's reagent in its conventional form, although effective for contaminant treatment, is impractical from an in‐situ field application perspective due to low pH requirements (i.e., pH 3‐4), and limited reagent mobility when introduced into the subsurface. Modified Fenton's processes that use chelated‐iron catalysts and stabilized hydrogen peroxide have been developed with the goal of promoting effective in‐situ field application under native pH conditions (i.e., pH 5‐7), while extending the longevity of hydrogen peroxide. Laboratory experiments conducted in soil columns packed with organic soil to compare modified Fenton's catalysts with conventional catalysts (acidified iron [II]) indicated superior mobility and sorption characteristics for modified Fenton's catalysts. Furthermore, the acidic pH of a conventional catalyst was buffered to the native soil range, leading to increased iron precipitation/adsorption following permeation through the soil column. The chelates present within the modified Fenton's catalyst showed greater affinity toward iron compared with the native soil and, hence, minimized iron loss through adsorption during the permeation process even at pH 5‐7. Field effectiveness of the modified Fenton's process was demonstrated at a former dry‐cleaning facility located in northeast Florida. Preliminary laboratory‐scale experiments were conducted on soil‐slurry and groundwater samples to test the process efficacy for remediation of chlorinated solvents. Based on successful experimental results that indicated a 94 percent (soil slurry) to 99 percent (groundwater) reduction of cis‐1,2‐DCE, PCE, and TCE, a field‐scale treatment program was initiated utilizing a plurality of dual‐zone direct push injection points installed in a grid fashion throughout the site. Results of treatment indicated a 72 percent reduction in total chlorinated contamination detected in the site groundwater following the first injection event; the reduction increased to 90 percent following the second injection event. © 2002 Wiley Periodicals Inc.     

Predicting employee aggression against coworkers,subordinates and supervisors: the roles of person behaviors and perceived workplace factors

Predictors of employee aggression against coworkers, subordinates, and supervisors were studied in a sample of 136 men employed full‐time. Person behaviors (history of aggression, amount of alcohol consumed) predicted aggression against a coworker. In contrast, aggression against a supervisor was predicted by two perceived workplace factors (procedural justice, workplace surveillance). However, neither person behaviors nor perceived workplace factors predicted aggression against a subordinate. In addition, person behaviors and perceived workplace factors interacted to predict aggression. First, procedural justice interacted with amount of alcohol consumed in predicting both aggression against a coworker and aggression against a subordinate. Secondly, both job security and procedural justice interacted with history of aggression in predicting aggression against a subordinate. Finally, job security and amount of alcohol consumed interacted to predict aggression against a subordinate. Results suggest that both the understanding and prediction of employee aggression will be enhanced by taking into account the target of employee aggression, and by including both perceived workplace factors and person behaviors as predictor variables. Copyright © 1999 John Wiley & Sons, Ltd.     

Citizen board issues and local newspaper coverage of risk,remediation, and environmental management: Six U.S. nuclear weapons facilities

We examined site‐specific advisory board (SSAB) minutes and local newspaper coverage of the Fernald, Hanford, Idaho, Oak Ridge, Rocky Flats, and Savannah River sites of the U.S. Department of Energy (US DOE) in order to determine the importance of risk‐related issues related to remediation and other forms of environmental management. About one‐third of SSAB issues were risk‐related, and these were disproportionately major issues at meetings. The media focused on risks associated with remediation and other forms of waste management. The analysis implies that contractors and government officials need to establish and maintain communications with advisory panels and accentuate these contacts well in advance of contemplated new actions. © 2008 Wiley Periodicals, Inc.     

Brownfield redevelopment as a smart growth option in the United States

An evaluation is made of brownfields redevelopment as a smart growth policy compared to purchase of land, restrictive growth policies, changing transportation patterns, promoting compact development designs on the metropolitan fringe, and regional government. In the US brownfields redevelopment has clear advantages with regard to environmental protection, moral imperative, and government and special interest reactions. Its rank with regard to economic feasibility, ability to respond to changes in technology, and public reaction are not clear. A great deal more research is needed, especially about the costs of brownfield redevelopment and public preferences for housing type and location to be certain about brownfields redevelopment as a viable smart growth option.     

An experimental study of habitat selection by birds in a coffee plantation

Unique components of tropical habitats, such as abundant vascular epiphytes, influence the distribution of species and can contribute to the high diversity of many animal groups in the tropics. However, the role of such features in habitat selection and demography of individual species has not been established. Understanding the mechanisms of habitat selection requires both experimental manipulation of habitat structure and detailed estimation of the behavioral and demographic response of animals, e.g., changes in movement patterns and survival probabilities. Such studies have not been conducted in natural tropical forest, perhaps because of high habitat heterogeneity, high species diversity, and low abundances of potential target species. Agroforestry systems support a less diverse flora, with greater spatial homogeneity which, in turn, harbors lower overall species diversity with greater numerical dominance of common species, than natural forests. Furthermore, agroforestry systems are already extensively managed and lend themselves easily to larger scale habitat manipulations than protected natural forest. Thus, agroforestry systems provide a good model environment for beginning to understand processes underlying habitat selection in tropical forest animals. Here, we use multistate, capture-recapture models to investigate how the experimental removal of epiphytes affected monthly movement and survival probabilities of two resident bird species (Common Bush-Tanager [Chlorospingus ophthalmicus] and Golden-crowned Warbler [Basileuterus culicivorus]) in a Mexican shade coffee plantation. We established two paired plots of epiphyte removal and control. We found that Bush-Tanagers were at least five times more likely to emigrate from plots where epiphytes were removed compared to control plots. Habitat-specific movement patterns were not detected in the warbler. However, unlike the Golden-crowned Warbler, Common Bush-Tanagers depend upon epiphytes for nest sites and (seasonally) for foraging. These dispersal patterns imply that active habitat selection based on the presence or absence of epiphytes occurs in C. ophthalmicus on our study area. Survival rates did not vary with habitat in either species. Interestingly, in both species, survival was higher in the nonbreeding season, when birds were in mixed-species flocks. Movement by Common Bush-Tanagers into areas with epiphytes occurred mostly during the breeding season, when mortality-driven opportunity was greatest.     

Birds as predators in tropical agroforestry systems

Insectivorous birds reduce arthropod abundances and their damage to plants in some, but not all, studies where predation by birds has been assessed. The variation in bird effects may be due to characteristics such as plant productivity or quality, habitat complexity, and/or species diversity of predator and prey assemblages. Since agroforestry systems vary in such characteristics, these systems provide a good starting point for understanding when and where we can expect predation by birds to be important. We analyze data from bird exclosure studies in forests and agroforestry systems to ask whether birds consistently reduce their arthropod prey base and whether bird predation differs between forests and agroforestry systems. Further, we focus on agroforestry systems to ask whether the magnitude of bird predation (1) differs between canopy trees and understory plants, (2) differs when migratory birds are present or absent, and (3) correlates with bird abundance and diversity. We found that, across all studies, birds reduce all arthropods, herbivores, carnivores, and plant damage. We observed no difference in the magnitude of bird effects between agroforestry systems and forests despite simplified habitat structure and plant diversity in agroforests. Within agroforestry systems, bird reduction of arthropods was greater in the canopy than the crop layer. Top-down effects of bird predation were especially strong during censuses when migratory birds were present in agroforestry systems. Importantly, the diversity of the predator assemblage correlated with the magnitude of predator effects; where the diversity of birds, especially migratory birds, was greater, birds reduced arthropod densities to a greater extent. We outline potential mechanisms for relationships between bird predator, insect prey, and habitat characteristics, and we suggest future studies using tropical agroforests as a model system to further test these areas of ecological theory.     

Secular and Faith-based Organisations as Reliable Information Sources for Residents of Environmentally Stressed Neighbourhoods

A sample of 873 residents of Accra, Ghana, and 504 residents of the state of New Jersey, USA, stratified by type of neighbourhood was gathered in order to determine the sources of information residents rely on for accurate information about their neighbourhoods. In both countries residents relied most heavily on personal contacts, television and radio, and much less on community organisations. Residents who rely on many sources for reliable information tend to have lived in their neighbourhood for a long time and to be more engaged in neighbourhood activities than those who reach out to fewer sources. Those who rely on secular community organisations tend to mistrust science, experts and local officials. Those who rely on faith-based organisations are much more trusting of local officials but are even less trusting of science and experts than their counterparts. The implications of these results for building and sustaining community organisations are discussed.