Effects of lipids on the sorption of hydrophobic organic compounds on geosorbents: a case study using phenanthrene

The impact of the lipid fraction of natural geosorbents on the sorption of a polycyclic aromatic hydrocarbon was assessed using several experiments. In the first set of experiments phenanthrene was sorbed on a coastal sediment as well as on its humin and humic acid fractions before and after lipid extraction. Before lipid extraction, sorption shows dominantly partitioning characteristics. However, the extraction of lipids from sediment and humin drastically increases, by up to one order of magnitude, their sorption affinity for phenanthrene at low sorbate concentrations, resulting in increased isotherm nonlinearity. This effect is less pronounced for humic acids. One mechanism proposed for the increasing sorption is that lipids, despite their very low relative abundance in the sediments, can compete with phenanthrene for specific high affinity sorption sites (e.g., matrix pores and adsorption sites). This competition is not surprising considering the similar hydrophobic nature of lipids and phenanthrene. Lipids, or any non-polar molecules, could also act like plasticizers by swelling rigid domains and disrupting high affinity sites. In both cases, the removal of lipids (and extraction solvents) makes those sites available for phenanthrene. These provide alternative explanations to the previously proposed “solvent conditioning effect” believed to occur when geosorbents are treated with non-polar solvents modifying the matrix structure, an effect yet to be proven at molecular scale. To further investigate the impact of lipids on sorption, other independent experiments were performed. In a second experiment, re-addition of lipids to the extracted sediment restored the sorption isotherm linearity observed in the native material supporting the absence of irreversible extraction artifacts. However, high addition of lipids (i.e., after saturation of high affinity sites) seems to also enlarge the low affinity partitioning domain. These results are consistent with dual-mode, hole-filling, sorption models involving diffusion. In the final set of experiments, solid-state ¹⁹F-NMR using F-labeled lipids sorbed onto the sediments confirmed that lipids may be in different domains (mobile or rigid) that interact or not with phenanthrene. The possible effects of lipid removal on sorption have been overlooked and should be considered when geosorbents are pretreated.     

Some direct observations on the ecology and behaviour of the Norway lobster Nephrops norvegicus

A detailed investigation of a small area of sea bed occupied by the Norway lobster Nephrops norvegicus (L.) was carried out by diving and television observations at depths of 30 m in Loch Torridon, Scotland. The density of burrows was 1/2 m², but only a proportion of these were occupied by N. norvegicus. Although about 70% of the larger burrows were occupied by N. norvegicus, giving a density of 1 lobster/8 m², very few juveniles (carapace length less than 30 mm) were found in the area. Many of the small burrows were occupied by the gobiid fish Lesueurigobius friesii (Collett). There was evidence that N. norvegicus frequently change their burrows, and fighting for burrows was observed. N. norvegicus remain within their burrows during the day, emerge around sunset to forage for food during the night, and then return to their burrows at dawn. This, and other aspects of their burrowing behaviour, have a marked effect on the commercial trawl catches of N. norvegicus which show large seasonal and diurnal variations in size and sex composition.     

Noble goals and challenging terrain: organic and fair trade coffee movements in the global marketplace

Social relations associated with conventional agricultural exports find their origins in long term associations based on business, family, and class alliances. Working outside these boundaries presents a host of challenges, especially where small producers with little economic or political power are concerned. Yet, in many developing countries, alternative trade organizations (ATOs) based on philosophies of social justice and/or environmental well-being are carving out spaces alongside traditional agricultural export sectors by establishing new channels of trade and marketing. Coffee provides a case in point, with the fair trade and certified organic movements making inroads into the market place. In their own ways, these movements represent a type of economic and social restructuring from below, drawing upon and developing linkages beyond the traditional boundaries of how coffee is produced and traded. An examination of the philosophies of the fair trade and organic coffee movements reveal that the philosophical underpinnings of both certified organic and fair-trade coffee run counter to the historical concerns of coffee production and trade. Associations of small producers involved in these coffees face stiff challenges – both internal and external to their groups. More work, especially in situ fieldwork aimed at uncovering the challenges, benefits, tensions, and successes, is needed to understand better the ways these networks operate in the dynamic agro-food complex.     

Prey growth and size-dependent predation in juvenile estuarine fishes: experimental and model analyses

The outcome of predation interactions between growing, size-structured predator and prey cohorts is difficult to predict. We manipulated the food resources available to juvenile spot subject to predation from southern flounder in a 60-day replicated pond experiment to test the hypothesis that spot growing slowly would experience higher predation mortality and stronger selection against small individuals than those growing rapidly. A nearly threefold difference in average growth rate between fast- and slow-growth treatments led to twofold higher predation mortality of slow-growing spot. Relative to no-flounder controls, larger spot were overrepresented at the end of the experiment in both treatments, but the magnitude of flounder size selection was much greater in the slow-growth treatment. The experimental results agreed qualitatively, but not quantitatively, with predictions from a prior size-dependent foraging model. In particular, the model significantly underestimated observed shifts in spot size structure to larger sizes. We hypothesized that competitive release and associated increases in spot growth due to thinning by flounder might reconcile this difference, and extended the model to incorporate this process. We then used the model to estimate the relative contribution of these two confounded predator effects (size-selective predation and thinning) to observed shifts in spot size structure. Model simulations indicated that the combined effects of size-selective predation and thinning could account for nearly all of the observed shift in spot size structure, but that thinning was the more important process. Our results highlight the utility of combining experimental and modeling approaches to unravel the complexities underlying interactions between growing, size-structured predator and prey cohorts.     

Implementation of the EU environmental noise directive: Lessons from the first phase of strategic noise mapping and action planning in Ireland

The first phase of noise mapping and action planning in Ireland, in accordance with EU Directive 2002/49/EC, is now complete. In total this included one agglomeration, one airport and approximately 600 km of major roads outside the agglomeration. These noise maps describe the level of noise exposure of approximately 1.25 million people. The first phase of noise mapping was dealt with by five noise mapping bodies while 26 action planning authorities were involved in the development of the associated action plans. The second phase of noise mapping, due to be completed in 2012, sees a reduction in the defined thresholds describing the required agglomerations, roads and railways that have to be mapped. This will have a significant impact on the extent of mapping required. In Ireland this will result in an increased number of local authorities being required to develop strategic noise maps for their area along with the further development of associated action plans. It is appropriate at this point to review the work process and results from the first phase of noise mapping in Ireland in order to establish areas that could be improved, throughout the noise mapping project. In this paper a review of the implementation procedures focussing on (dominant) road traffic noise is presented. It is identified that more standardisation is needed and this could be achieved by the establishment of a national expert steering group.     

Environmental response to intentional dissemination of Bacillus anthracis spores in the United States–2001

The intentional dissemination of Bacillus anthracis (anthrax) spores at multiple locations in the United States in the fall of 2001 resulted not only in several deaths and illnesses (including psychological effects), but likely changed lifestyles and attitudes, and increased the public's awareness of individual vulnerability. While federal resources had previously been committed to preparing local public health agencies for counter‐terrorism activities and to enhance environmental and medical response, these release episodes have increased the consistency of environmental and medical response activities, and increased government resources for homeland security. This article abstracts current information from many sources that summarize the environmental responses to the anthrax releases. The article discusses the international agreements and the U.S. regulations concerning biological weapons, the characteristics of the anthrax organism, potential exposure pathways, adverse health conditions resulting from inhalation exposure, the environmental response to two specific release episodes, environmental sampling and analytical procedures, recommended personal protective equipment, and the subsequent federal efforts to improve response capabilities. © 2003 Wiley Periodicals, Inc.     

Work-Family conflict: The effect of job and family involvement

A review of past research revealed inconsistent findings concerning the relationship between job involvement and work-family conflict. This study tested whether family involvement moderates the relationship between job involvement and work-family conflict. Two types of family involvement (spouse and parent) and two types of work-family conflict (job-spouse and job-parent) were assessed. Data were gathered via questionnaire from a sample of nonteaching professionals employed by a large public university in the northeastern United States. As hypothesized, job involvement and job-spouse conflict were positively related for individuals high in spouse involvement and unrelated for individuals low in spouse involvement. Contrary to prediction, parental involvement did not moderate the relationship between job involvement and job-parent conflict. Instead, job involvement was positively related to job-parent conflict regardless of the level of parental involvement. Results are discussed in terms of standards for role performance and strength of role demands. Implications for future research are also discussed.