Characterization of PM2.5-bound polycyclic aromatic hydrocarbons in Atlanta

Twenty-four hour PM_2.5 samples from a rural site, an urban site, and a suburban site (next to a major highway) in the metropolitan Atlanta area in December 2003 and June 2004 were analyzed for 19 polycyclic aromatic hydrocarbons (PAH). Extraction of the air samples was conducted using an accelerated solvent extraction method followed by isotope dilution gas chromatography/mass spectrometry determination. Distinct seasonal variations were observed in total PAH concentration (i.e. significantly higher concentrations in December than in June). Mean concentrations for total particulate PAHs in December were 3.16, 4.13, and 3.40 ng m^?3 for the urban, suburban and rural sites, respectively, compared with 0.60, 0.74, and 0.24 ng m^?3 in June. Overall, the suburban site, which is impacted by a nearby major highway, had higher PAH concentration than did the urban site. Total PAH concentrations were found to be well correlated with PM_2.5, organic carbon (OC), and elemental carbon (EC) in both months (r² = 0.36–0.78, p < 0.05), although the slopes from the two months were different. PAHs represented on average 0.006% of total PM_2.5 mass and 0.017% of OC in June, compared with 0.033% of total PM_2.5 and 0.14% of OC in December. Total PAH concentrations were also correlated with potassium ion (r² = 0.39, p = 0.014) in December, but not in June, suggesting that in winter biomass burning can potentially be an important source for particulate PAH. Retene was found at a higher median air concentration at the rural site than at the urban and suburban sites—unlike the rest of the PAHs, which were found at lower levels at the rural site. Retene also had a larger seasonal difference and had the weakest correlation with the rest of the PAHs measured, suggesting that retene, in particular, might be associated with biomass burning.     

Children and fighting forces: 10 years on from Cape Town

It is 10 years since the adoption of the Cape Town Principles and Best Practices on the Prevention of Recruitment of Children into the Armed Forces and on Demobilization and Social Reintegration of Child Soldiers in Africa. The field of programming for the reintegration of children associated with armed forces and armed groups has made significant strides in this period. However, important gaps in the knowledge base remain. This paper examines empirical evidence that supports lessons learned from work with children formerly connected with fighting forces. It evaluates what is known, where promising practice exists, and lacunae in five programming areas: psychosocial support and care; community acceptance; education, training and livelihoods; inclusive programming for all war-affected children; and follow-up and monitoring. While the 2007 Paris Commitments to Protect Children from Unlawful Recruitment or Use by Armed Forces or Groups mark an emerging consensus on many issues, there is still a critical need for more systematic studies to develop the evidence base supporting intervention in this area.     

Towards implementation and achievement of sustainable biofuel development in Africa

Although sustainable bioenergy development in Africa is critically debated, if projects are developed within a credible framework, opportunities for sustainability arguably can arise. This paper presents research on the characteristics of sustainable biofuel projects as provided in the literature and according to expert opinions obtained by way of a survey involving thirty-eight international experts. Participants were selected for their expertise in the fields of environmental, social and economic sustainability relating to biofuels in Africa. The survey results suggest that projects which display a high degree of transparency, incorporate local stakeholder involvement, and ideally include local villagers as partners are more likely to achieve sustainable biofuel production. Experts also indicated that reconciling diverse stakeholder objectives alongside the principles of sustainable development remains an ongoing challenge. A process is recommended for sustainable biofuel development, which attempts to harmonise efficiency, stakeholder interaction and the integration of diverse stakeholder perspectives. To support the process, it is recommended that an advisory/mediating body that acts according to best practice principles would be of great assistance. Such an advisory/mediating body would be conversant with local land, social, economic and environmental conditions, project sustainability and administration, and also advise on biofuel framework educational needs.     

“My garden is an expression of me”: Exploring householders' relationships with their gardens

Domestic gardens offer immense potential as sites for native biodiversity conservation. In urban areas they often comprise the largest land use, thus presenting an accessible and immediate way for urban dwellers to connect with nature and to support and enhance native biodiversity. This paper presents findings from a study of 55 domestic gardens undertaken in Dunedin, New Zealand, which explores householders' relationships with their gardens. The study data was derived from two interviews with householders, two photo exercises (approximately a year apart), together with a number of biological studies of the gardens. Gardens proved to be very important for our householders; for physical and mental health, as an expression of ownership and identity, as sites for social relationships, for connecting with nature and as site of domestic produce production. Householders' connections with nature were idiosyncratic, multifaceted and exhibited in ways that are more complex and varied than those usually considered by those working in the natural sciences and indeed biophilia supporters. We emphasize the importance of the people side of nature in seeking to build and support positive ecological change in the urban environment and the value of combining natural and social science approaches.     

Bioenergy project appraisal in sub‐Saharan Africa: Sustainability barriers and opportunities in Zambia

Although there is continuing debate surrounding biofuel cultivation (especially in developing nations) in relation to issues of exploitation, land grabbing, poverty alleviation and energy security, there is a lack of empirical evidence to assess how these debates are playing out in practice on the ground. Drawing on political ecology discourse, this paper examines case studies of biofuel production in Zambia and the effects they have on environmental and social sustainability. During April and May 2011, data were collected on two case study projects involving Jatrophacurcas feedstock cultivation in Zambia. Semi‐structured interviews were used to ascertain views from affected stakeholders (local farmers, local environmental, social, and agronomic experts, and investors) on the biofuel projects and their environmental and social impacts. The findings suggest that the uneven distribution of costs and benefits are brought about by imbalances in knowledge, access to resources and the allocation of social and political influence (often associated with broader discourses of development), and this provides a likely rationale for a lack of sustainability in biofuel projects. Drawing on these viewpoints, as well as on field observations, this paper outlines the barriers and opportunities linked to Jatrophacurcas project sustainability.     

Livelihood adaptations to climate variability: insights from farming households in Ghana

Climate variability poses a significant threat to many sectors of Sub-Saharan Africa’s economy. Agriculture is one of the most climate sensitive sectors because of its dependence on rain-fed cultivation. This paper identifies the main adaptation strategies used by farming households in the Sudan savannah and forest-savannah transitional agro-ecological zones of Ghana, in order to reduce the adverse impacts of climate variability on their livelihood activities. It combines questionnaire surveys, key informant interviews and a range of participatory methods. Results show that households employ a range of on- and off-farm adaptation strategies including changing the timing of planting, planting early maturing varieties, diversification of crops, support from family and friends, and changing their diets to manage climate variability. Results reveal that most households use adaptation strategies linked to livelihood diversification to adapt to the increased climate variability seen in recent decades. Most households now engage in multiple non-arable farming livelihood activities in an attempt to avoid destitution because of crop failure linked to climate variability (particularly drought). The findings suggest that policy makers need to formulate more targeted climate adaptation policies and programmes that are linked to enhancing livelihood diversification, as well as establishing communication routes for farming communities to better share their knowledge on successful local climate adaptation strategies.     

Hazardous Pollutants in Class II Landfills

Class II landfills accept nontoxic municipal trash. Their gaseous emissions were originally assumed to be relatively free of hazardous substances. However, one Class II site in Southern California was found to be emitting enough vinyl chloride to exceed the California Air Quality Standard of 10 ppb for a 24-hour average in surrounding neighborhood. This paper presents a summary of the results of the analysis of landfill gas from over 20 additional Class II landfills. Ambient air surveys were conducted around five of the landfills. About 90 percent of the landfills contained measurable amounts of vinyl chloride and/or benzene. The concentrations exceeded 1 ppm in about half of the sites studied. Vinyl chloride is produced in situ by the action of bacteria on chlorinated solvents, and can be found in landfills that have been closed for over 30 years. The relative amounts of methane and vinyl chloride vary so much within a single landfill that methane measurements cannot be used as a surrogate for vinyl chloride     

Transport of Escherichia coli bacteria through laboratory columns of glacial-outwash sediments: estimating model parameter values based on sediment characteristics

Bacterial transport through cores of intact, glacial-outwash aquifer sediment was investigated with the overall goal of better understanding bacterial transport and developing a predictive capability based on the sediment characteristics. Variability was great among the cores. Normalized maximum bacterial-effluent concentrations ranged from 5.4x10(-7) to 0.36 and effluent recovery ranged from 2.9x10(-4) to 59%. Bacterial breakthrough was generally rapid with a sharp peak occurring nearly twice as early as the bromide peak. Bacterial breakthrough exhibited a long tail of relatively constant concentration averaging three orders of magnitude less than the peak concentration for up to 32 pore volumes. The tails were consistent with non-equilibrium detachment, corroborated by the results of flow interruption experiments. Bacterial breakthrough was accurately simulated with a transport model incorporating advection, dispersion and first-order non-equilibrium attachment/detachment. Relationships among bacterial transport and sediment characteristics were explored with multiple regression analyses. These analyses indicated that for these cores and experimental conditions, easily-measurable sediment characteristics--median grain size, degree of sorting, organic-matter content and hydraulic conductivity--accounted for 66%, 61% and 89% of the core-to-core variability in the bacterial effective porosity, dispersivity and attachment-rate coefficient, respectively. In addition, the bacterial effective porosity, median grain size and organic-matter content accounted for 76% of the inter-core variability in the detachment-rate coefficient. The resulting regression equations allow prediction of bacterial transport based on sediment characteristics and are a possible alternative to using colloid-filtration theory. Colloid-filtration theory, used without the benefit of running bacterial transport experiments, did not as accurately replicate the observed variability in the attachment-rate coefficient.     

Scale-dependent spatial variability in peatland lead pollution in the southern Pennines, UK

Increasingly, within-site and regional comparisons of peatland lead pollution have been undertaken using the inventory approach. The peatlands of the Peak District, southern Pennines, UK, have received significant atmospheric inputs of lead over the last few hundred years. A multi-core study at three peatland sites in the Peak District demonstrates significant within-site spatial variability in industrial lead pollution. Stochastic simulations reveal that 15 peat cores are required to calculate reliable lead inventories at the within-site and within-region scale for this highly polluted area of the southern Pennines. Within-site variability in lead pollution is dominant at the within-region scale. The study demonstrates that significant errors may be associated with peatland lead inventories at sites where only a single peat core has been used to calculate an inventory. Meaningful comparisons of lead inventories at the regional or global scale can only be made if the within-site variability of lead pollution has been quantified reliably.     

Best management practices for environmental restoration programs

Based on a review of hundreds of environmental restoration program optimization reviews, this article describes management tools found in successful and efficient remediation programs. Projects that consistently struggled to achieve their objectives were observed to be missing certain, or to have inadequately used, these tools. The tools are articulated as best practices because when they are present and actively used, project shortcomings were minimal. Priority objectives for site owners and project managers include improving efficiency and effectiveness through performance management, reducing resource usage and energy consumption, ensuring protectiveness, and reducing uncertainty in management decision making. Restoring environmental resources damaged by historic waste management practices began in earnest in the late 1960s and early 1970s with the broad recognition of the problems caused by environmental discharges and spills when wastes are not managed appropriately. Under new regulations, soil and groundwater remediation projects could be, and were, conducted within a defined framework. The number and variety of restoration projects that were launched resulted in a slew of projects progressing through the stages of characterization, decision, and cleanup, and more were added to the cleanup process each year. In the 1990s, the Department of Defense noted that many cleanup efforts were projected to incur substantial operational, maintenance, and monitoring costs for decades into the future. This was correctly perceived as an opportunity to optimize those systems and programs, minimize costs, and reduce health and environmental risks. The best practices outlined in this article address management tools that were identified in optimization efforts that led to effective and efficient environmental remediation projects. © 2010 Wiley Periodicals, Inc.