Effects of pH, temperature, and water quality on chloride removal with ultra-high lime with aluminum process.

The ultra high-lime with aluminum process (UHLA) has the ability to remove sulfate and chloride in addition to other scale-forming materials from recycled cooling water. Laboratory experiments have demonstrated that the UHLA process can achieve high chloride removal from recycled cooling water, and an equilibrium model was developed to describe chemical behavior during chloride removal. This paper describes the influence of pH, temperature, and initial chloride concentration on chloride removal by UHLA and identifies the precipitated solids formed during treatment. The optimum pH for maximum chloride removal efficiency was found to be 12 +/- 0.2. Chloride removal efficiency was higher at a high initial chloride concentration than at a low initial chloride concentration with the chemical doses used. Solids formed during UHLA treatment were identified by x-ray diffraction as calcium chloroaluminate, tricalcium hydroxyaluminate, and tetracalcium hydroxyaluminate. This supports the assumption of the equilibrium model that these compounds are present and form a solid solution.     

Evaluation of natural attenuation at a 1,4‐dioxane‐contaminated site

1,4‐Dioxane entered the environment as a result of historic leaks and spills in the production area at an industrial facility in the southeastern coastal plain. The areal extent of the 1,4‐dioxane plume is several hundred acres and is largely contained on the site. Land use adjacent to the plant property is primarily undeveloped (wetlands or woods) or industrial, with a small area of mixed land use (commercial/residential) to the southwest and north. The surficial aquifer is a relatively simple hydrogeologic system with well‐defined boundaries and is comprised of a 50‐ to 70‐foot‐thick deposit of alluvial/fluvial sand and gravel that overlies an aquitard in excess of 100 feet thick. A groundwater flow model, developed and calibrated using field‐measured data, was used for the fate‐and‐transport modeling of 1,4‐dioxane. The flow‐and‐transport model, combined with the evaluation of other site geochemical data, was used to support the selection of monitored natural attenuation (MNA) as the proposed groundwater remedy for the site. Since the active sources of contamination have been removed and the modeling/field data demonstrated that the plume was stable and not expanding, the proposed MNA approach was accepted and approved by the regulatory agency for implementation in 2004. Subsequent accumulated data confirm that concentrations in the 1,4‐dioxane plume are declining as predicted by the fate‐and‐transport modeling. © 2008 Wiley Periodicals, Inc.     

The Lost Creek Fire: managing social relations under disaster conditions

This paper examines some of the social processes associated with disaster conditions. Utilising an asset‐based perspective of community capacity, it focuses on four types of normative systems to interpret the ability of communities to manage disasters through market‐, bureaucratic‐, associative‐, and communal‐based norms. Drawing on experience of a wildfire in the Crowsnest Pass region of southwest Alberta, Canada, in 2003, the tensions and compatibilities among these normative systems are evaluated through interviews with 30 community leaders. The results confirm the contributions of all types of social capital to resiliency, the necessity for rapid use of place‐based knowledge, and the importance of communication among all types and levels of agents. In addition, they point to the value of identifying and managing potential conflicts among the normative systems as a means to maximising their contributions. The integration of local networks and groups into the more general disaster response minimised the impacts on health and property.     

A comprehensive evaluation of the potential chemical defenses of antarctic ascidians against sympatric fouling microorganisms

The present study analyzed the bioactivity of whole body extracts from six solitary and eight colonial ascidian taxa against 20 sympatric bacterial isolates and one sympatric diatom species from the Western Antarctic Peninsula. Ascidians had crude lipophilic and hydrophilic extracts assayed against 20 bacterial strains. The lipophilic extract of one ascidian caused growth inhibition in all bacterial isolates at 3× tissue-level concentrations. The lipophilic and hydrophilic extracts were fractionated into seawater-soluble and insoluble fractions and assayed at three concentrations against a sympatric diatom species. Significant diatom mortality was detected at 3× and 1× concentrations in all but one ascidian taxon. Lipophilic fractions caused higher diatom mortality than hydrophilic extracts. The specificity of secondary metabolites against diatom fouling and the lack of activity against bacteria suggest high selective pressure for chemical defenses against diatom fouling or the potential that bacterial pathogens are controlled by the ascidian immune system.     

A structural equation model to integrate changes in functional strategies during old-field succession

From a functional perspective, changes in abundance, and ultimately species replacement, during succession are a consequence of integrated suites of traits conferring different relative ecological advantages as the environment changes over time. Here we use structural equations to model the interspecific relationships between these integrated functional traits using 34 herbaceous species from a Mediterranean old-field succession and thus quantify the notion of a plant strategy. We measured plant traits related to plant vegetative and reproductive size, leaf functioning, reproductive phenology, seed mass, and production on 15 individuals per species monitored during one growing season. The resulting structural equation model successfully accounts for the pattern of trait covariation during the first 45 years post-abandonment using just two forcing variables: time since site abandonment and seed mass; no association between time since field abandonment and seed mass was observed over these herbaceous stages of secondary succession. All other predicted traits values are determined by these two variables and the cause-effect linkage between them. Adding pre-reproductive vegetative mass as a third forcing variable noticeably increased the predictive power of the model. Increasing the time after abandonment favors species with increasing life span and pre-reproductive biomass and decreasing specific leaf area. Allometric coefficients relating vegetative and reproductive components of plant size were in accordance with allometry theory. The model confirmed the trade-off between seed mass and seed number. Maximum plant height and seed mass were major determinants of reproductive phenology. Our results show that beyond verbal conceptualization, plant ecological strategies can be quantified and modeled.     

Air emission inventories in North America: a critical assessment

Although emission inventories are the foundation of air quality management and have supported substantial improvements in North American air quality, they have a number of shortcomings that can potentially lead to ineffective air quality management strategies. Major reductions in the largest emissions sources have made accurate inventories of previously minor sources much more important to the understanding and improvement of local air quality. Changes in manufacturing processes, industry types, vehicle technologies, and metropolitan infrastructure are occurring at an increasingly rapid pace, emphasizing the importance of inventories that reflect current conditions. New technologies for measuring source emissions and ambient pollutant concentrations, both at the point of emissions and from remote platforms, are providing novel approaches to collecting data for inventory developers. Advances in information technologies are allowing data to be shared more quickly, more easily, and processed and compared in novel ways that can speed the development of emission inventories. Approaches to improving quantitative measures of inventory uncertainty allow air quality management decisions to take into account the uncertainties associated with emissions estimates, providing more accurate projections of how well alternative strategies may work. This paper discusses applications of these technologies and techniques to improve the accuracy, timeliness, and completeness of emission inventories across North America and outlines a series of eight recommendations aimed at inventory developers and air quality management decision-makers to improve emission inventories and enable them to support effective air quality management decisions for the foreseeable future.     

Taking Action Against Ocean Acidification: A Review of Management and Policy Options

Ocean acidification has emerged over the last two decades as one of the largest threats to marine organisms and ecosystems. However, most research efforts on ocean acidification have so far neglected management and related policy issues to focus instead on understanding its ecological and biogeochemical implications. This shortfall is addressed here with a systematic, international and critical review of management and policy options. In particular, we investigate the assumption that fighting acidification is mainly, but not only, about reducing CO₂ emissions, and explore the leeway that this emerging problem may open in old environmental issues. We review nine types of management responses, initially grouped under four categories: preventing ocean acidification; strengthening ecosystem resilience; adapting human activities; and repairing damages. Connecting and comparing options leads to classifying them, in a qualitative way, according to their potential and feasibility. While reducing CO₂ emissions is confirmed as the key action that must be taken against acidification, some of the other options appear to have the potential to buy time, e.g. by relieving the pressure of other stressors, and help marine life face unavoidable acidification. Although the existing legal basis to take action shows few gaps, policy challenges are significant: tackling them will mean succeeding in various areas of environmental management where we failed to a large extent so far.     

Public Health,Ethics, and Functional Foods

Functional foods aim to provide a positive impact on health and well-being beyond their nutritive content. As such, they are likely candidates to enhance the public health official’s tool kit. Or are they? Although a very small number of functional foods (e.g., phytosterol-enriched margarine) show such promise in improving individual health that Dutch health insurance companies reimburse their costs to consumers, one must not draw premature conclusions about functional foods as a group. A large number of questions about individual products’ safety, efficacy, and affordability need to be answered before they might become an important part of the public health agenda. More importantly, though, the costs and benefits of functional foods relative to alternative mechanisms of public health improvement need to be ascertained. Alternative scenarios that warrant investigation are mainly the supply of nutraceutical ingredients in pill form targeting “at risk” groups and consumer education on diet and lifestyle.