Release of substituents from phenolic compounds during oxidative coupling reactions

Phenolic compounds originating from plant residue decomposition or microbial metabolism form humic-like polymers during oxidative coupling reactions mediated by various phenoloxidases or metal oxides. Xenobiotic phenols participating in these reactions undergo either polymerization or binding to soil organic matter. Another effect of oxidative coupling is dehalogenation, decarboxylation or demethoxylation of the substrates. To investigate these phenomena, several naturally occurring and xenobiotic phenols were incubated with various phenoloxidases (peroxidase, laccase, tyrosinase) or with birnessite (delta-MnO(2)), and monitored for chloride release, CO(2) evolution, and methanol or methane production. The release of chloride ions during polymerization and binding ranged between 0.2% and 41.4%. Using the test compounds labeled with 14C in three different locations (carboxyl group, aromatic ring, or aliphatic chain), it was demonstrated that 14CO(2) evolution was mainly associated with the release of carboxyl groups (17.8-54.8% of the initial radioactivity). Little mineralization of 14C-labeled aromatic rings or aliphatic carbons occurred in catechol, ferulic or p-coumaric acids (0.1-0.7%). Demethoxylation ranged from 0.5% to 13.9% for 2,6-dimethoxyphenol and syringic acid, respectively. Methylphenols showed no demethylation. In conclusion, dehalogenation, decarboxylation and demethoxylation of phenolic substrates appear to be controlled by a common mechanism, in which various substituents are released if they are attached to carbon atoms involved in coupling. Electron-withdrawing substituents, such as -COOH and -Cl, are more susceptible to release than electron-donating ones, such as -OCH(3) and -CH(3). The release of organic substituents during polymerization and binding of phenols may add to CO(2) production in soil.     

Contrasting the core beliefs regarding the effective implementation of wind power. An international study of stakeholder perspectives

This paper analyses patterns in beliefs about the implementation of wind power as part of a geographical comparison of onshore wind power developments in the Netherlands, North-Rhine Westphalia and England. Q methodology is applied, in order to systematically compare the patterns in stakeholder views on the institutional conditions and changes in the domains of energy policy, spatial planning and environmental policy. Three factors represent support for wind power implementation from fundamentally different perspectives. The fourth perspective is critical opposed to wind power developments as well as critical to the manner in which wind projects are proposed, planned and implemented. These four perspectives exist across the geographical cases; however, some perspectives are prominent in one case and marginal in another. This relates to different legacies and varying implementation achievements in the three cases. The analysis shows that an approach that focuses on implementing as much wind power as possible, relying on technocratic reasoning and hierarchical policies is in practice the least successful, whereas collaborative perspectives with more emphasis on local issues and less on the interests of the conventional energy sector were particularly dominant in the most successful case, North-Rhine Westphalia.     

Evolutionary social and biogeophysical changes in the Amazon,Ganges–Brahmaputra–Meghna and Mekong deltas

Policy-making in social-ecological systems increasingly looks to iterative, evolutionary approaches that can address the inherent complexity of interactions between human wellbeing, provision of goods, and the maintenance of ecosystem services. Here, we show how the analysis of available time-series in tropical delta regions over past decades can provide important insight into the social-ecological system dynamics in deltaic regions. The paper provides an exploratory analysis of the recent changes that have occurred in the major elements of three tropical deltaic social-ecological systems, such as demography, economy, health, climate, food, and water. Time-series data from official statistics, monitoring programmes, and Earth observation data are analysed to explore possible trends, slow and fast variables, and observed drivers of change in the Amazon, Ganges–Brahmaputra–Meghna and Mekong deltas. In the Ganges–Brahmaputra–Meghna delta zone, increasing gross domestic product and per capita income levels since the 1980s mirror rising levels of food and inland fish production. In contrast, non-food ecosystem services, such as water availability, water quality, and land stability appear to be deteriorating. In the Amazon delta, natural and anthropogenic perturbations are continuously degrading key ecosystem services, such as carbon storage in biomass and soils, the regulation of water balance, and the modulation of regional climate patterns. In the Mekong delta, rapid economic development, changing land-use practices, and salinity intrusion are progressively putting more pressure on the delivery of important provisioning services, such as rice and inland aquaculture production, which are key sources of staple food, farm incomes, and export revenue. Observed changes in many key indicators of ecosystem services point to a changing dynamic state and increased probability of systemic threshold transformations in the near future.     

A Special Issue from the NARSTO Symposium on Tropospheric Aerosols

This dedicated issue of the Journal of the Air & Waste Management Association contains nine peer-reviewed scientific papers that were presented at the NARSTO Symposium on Tropospheric Aerosols: Science and Decisions in an International Community, held October 24-26, 2000, in Querétaro, Mexico.¹ Other peer-reviewed papers^2-9 appear in a companion issue of Science of the Total Environment to be published in February 2002. More than 130 papers were presented in platform and poster sessions at the meeting. Approximately 28% of the technical presentations dealt with topics from Mexico, and 15% related to Canada, with the remainder discussing U.S. and global topics.     

How Stable are Public Responses to Changing Local Environments? A 'Before' and 'After' Case Study of River Restoration

This paper considers the stability of public responses to an urban river restoration scheme on the River Skerne, Darlington, UK, by comparing the results from surveys of local residents carried out before and after scheme implementation. This case study provides evidence of strong and generally consistent positive responses to the proposals and implemented scheme to return the straightened and channelized river to a more natural condition although support was more qualified after than before implementation. Although the scheme design and construction costs were high, nearly two-thirds regarded the scheme as value for money. Exploratory contingent valuation results on whether or not local residents were prepared to pay for the scheme were broadly stable over the two surveys.     

Recursive residuals and model diagnostics for normal and non-normal state space models

Model diagnostics for normal and non-normal state space models are based on recursive residuals which are defined from the one-step ahead predictive distribution. Routine calculation of these residuals is discussed in detail. Various diagnostic tools are suggested to check, for example, for wrong observation distributions and for autocorrelation. The paper also discusses such topics as model diagnostics for discrete time series and model discrimination via Bayes factors. The case studies cover environmental applications such as analysing a time series of the number of daily rainfall occurrences and a time series of daily sulfur dioxide emissions.     

Ciprofloxacin adsorption from aqueous solution onto chemically prepared carbon from date palm leaflets

A chemically prepared carbon was synthesized from date palm leaflets via sulphuric acid carbonization at 160℃. Adsorption of ciprofloxacin (CIP) from aqueous solution was investigated in terms of time, pH, concentration, temperature and adsorbent status (wet and dry). The equilibrium time was found to be 48 hr. The adsorption rate was enhanced by raising the temperature for both adsorbents, with adsorption data fitting a pseudo second-order model well. The activation energy, E_a, was found to be 17 kJ/mol, indicating a diffusion-controlled, physical adsorption process. The maximum adsorption was found at initial pH 6. The wet adsorbent showed faster removal with higher uptake than the dry adsorbent, with increased performance as temperature increased (25-45℃). The equilibrium data were found to fit the Langmuir model better than the Freundlich model. The thermodynamic parameters showed that the adsorption process is spontaneous and endothermic. The adsorption mechanism is mainly related to cation exchange and hydrogen bonding.     

Copper ecotoxicology of marine algae: a methodological appraisal

The production of accurate and reliable data on copper ecotoxicology of marine algae depends on the use of trace metal clean techniques during experimentation. We reviewed the methodologies used in the literature on copper ecotoxicology of marine macro- and microalgae, specifically the use of trace metal clean procedures such as the labware used (glassware vs. plasticware), methods of cleaning the labware (acid soaking and ultrapure water rinsing), stock solution preparation (copper source and acidification), and measurement and reporting of dissolved copper concentrations. In terms of taxonomic classification, the most studied algal groups were the Phyla Ochrophyta, Bacillariophyta, Rhodophyta, and Chlorophyta. In terms of methodology, ～50% of the articles did not specify the labware, ～25% used glassware, and ～25% plasticware; ～30% of the studies specified cleaning protocols for labware to remove trace metal impurities; the copper form used to prepare the stock solutions was specified in ～80% of studies but acidification to stabilise the dissolved copper was performed in only ～20%; and the dissolved copper concentration was measured in only ～40% of studies. We discuss the importance of following trace metal clean techniques for the comparison and interpretation of data obtained on copper ecotoxicology in algae.     

Risk communication in emergency response to a simulated extreme flood

Risk communication in flood incident management can be improved through developing hydrometeorological and engineering models used as tools for communicating risk between scientists and emergency management professionals. A range of such models and tools was evaluated by participating flood emergency managers during a 4-day, real-time simulation of an extreme event in the Thamesmead area in the Thames estuary close to London, England. Emergency managers have different communication needs and value new tools differently, but the indications are that a range of new tools could be beneficial in flood incident management. Provided they are communicated large model uncertainties are not necessarily unwelcome among flood emergency managers. Even so they are cautious about sharing the ownership of weather and flood modelling uncertainties.