Controlling Air Toxics Emissions From Remediation by Monitoring of Surrogate Parameters

Particulate matter (dust) from remediation and demolition sites may pose a potential risk to the nearby public due to the presence of various contaminants. Unfortunately, there are no good options for real‐time monitoring of metals, polychlorinated biphenyls, etc. in wind‐blown dust. A three‐tiered approach involving a combination of real‐time monitoring and off‐site analysis that has proved successful is described in this article. PM₁₀ is used as a surrogate parameter for metals and other nonvolatile pollutants, and real‐time monitoring is used to guide dust control measures. If dust emissions are controlled, air emissions of metals and other nonvolatile pollutants also are controlled. © 2014 Wiley Periodicals, Inc.     

The Great Recession or progressive energy policies? Explaining the decline in US greenhouse gas emissions forecasts

This paper evaluates the causes of the 23% decline in 2030 US greenhouse gas emissions forecasts between 2007 and 2011. Dynamic regression modeling predicts that the Great Recession contributed to about 67% of the 2008–2009 emissions decline, but then fell to about an 18% share for the 2030 emissions forecast. An analysis of electricity generation forecasts show that switching from coal to gas contributed only 6% to the total 2030 decline. In contrast, regulatory impact assessments and policy analysis showed that state and federal policies were responsible for 46% of the 2030 decline in emissions.     

Junge relationships in measurement data for cyclic siloxanes in air

In 1974, Junge postulated a relationship between variability of concentrations of gases in air at remote locations and their atmospheric residence time, and this Junge relationship has subsequently been observed empirically for a range of trace gases. Here, we analyze two previously-published datasets of concentrations of cyclic volatile methyl siloxanes (cVMS) in air and find Junge relationships in both. The first dataset is a time series of concentrations of decamethylcyclopentasiloxane (D₅) measured between January and June, 2009 at a rural site in southern Sweden that shows a Junge relationship in the temporal variability of the measurements. The second dataset consists of measurements of hexamethylcyclotrisiloxane (D₃), octamethylcyclotetrasiloxane (D₄) and D₅ made simultaneously at 12 sites in the Global Atmospheric Passive Sampling (GAPS) network that shows a Junge relationship in the spatial variability of the three cVMS congeners. We use the Junge relationship for the GAPS dataset to estimate atmospheric lifetimes of dodecamethylcyclohexasiloxane (D₆), 8:2–fluorotelomer alcohol and trichlorinated biphenyls that are within a factor of 3 of estimates based on degradation rate constants for reaction with hydroxyl radical determined in laboratory studies.     

Low-heat alkaline pretreatment of biomass for dairy anaerobic codigestion

In this research, low-heat alkaline pretreatment was evaluated to determine the extent to which urban landscape waste (yard waste), corn stover, and switchgrass could be codigested under conditions typical of US farm-based anaerobic digestion (AD). Waste heat from combined heat and power (CHP) units associated with AD could make such pretreatment economical. Short-term batch digestion studies and 8-week continuous-feed studies were used to screen and evaluate various pretreatment conditions. Results indicate that maple and oak leaves did not digest well, even with pretreatment. Pretreatment did improve digestion of corn leaves and stalks as well as switchgrass. However, these materials also digested reasonably well even without pretreatment. No digester operational problems were observed during continuous-feed studies of intermittently stirred bench top digesters, but optimal levels of alkali, temperature, and pretreatment time may be specific to the feedstock, particle size, and digester loading rate. Results suggest that some common lignocellulosic biomass materials, such as corn stover and switchgrass, could be successfully codigested in many existing farm-based digesters. Interestingly, without pretreatment, switchgrass digestion improved over 20-fold when digested with seed culture from a dairy digester compared to seed culture from a municipal digester, suggesting that culture acclimation could be as important as pretreatment in improving digestion of specific lignocellulosic feedstocks.     

Just and Sustainable? Examining the Rhetoric and Potential Realities of UK Food Security

The dominant discourse in 20th century UK food and agricultural policies of a liberal, free trade agenda was modified at the turn of the 21st to embrace ecological sustainability and “food security.” The latter term has a long international history; the relationship between issues of technical production and equality of distributional access are also much debated. The paper examines shifts in UK policy discourse in the context of international research, policy, and initiatives to promote food security, and highlights the implications for social justice in and through the food system.     

Biodegradation of PCBs by ligninolytic fungi and characterization of the degradation products

The aim of the present study was to compare the degrading capabilities of eight ligninolytic fungal representatives towards a technical mixture of polychlorinated biphenyls (Delor 103). Axenic cultures of the fungi, either in complex or N-limited liquid media, were spiked with the technical mixture of Delor 103. All of the fungal strains were able to degrade the pollutant significantly after 6weeks of incubation in both media. Outstanding results were achieved by the treatment with Pleurotus ostreatus, which removed 98.4% and 99.6% of the PCB mixture in complex and mineral media, respectively. This fungus was the only one capable of breaking down penta- and hexachlorinated biphenyls in the complex medium. Ecotoxicological assays performed with the luminescent bacterium Vibrio fischeri demonstrated that all of the fungal strains employed in this study were able to remove the toxicity only temporarily (e.g., after 28d of incubation), while P. ostreatus was capable of suppressing the toxicity associated to PCBs along the whole incubation period in both media. We also performed an extensive set of qualitative GC/MS analyses and chlorinated derivatives of hydroxy- and methoxy-biphenyls were detected along with monoaromatic structures, i.e. chlorobenzoic acids, chlorobenzaldehydes and chlorobenzyl alcohols. This results indicate that both intracellular (cytochrome P-450 monooxigenase, aryl-alcohol dehydrogenase and aryl-aldehyde dehydrogenase) and extracellular (ligninolytic enzymes) enzymatic systems could be involved in the biotransformation of PCB by ligninolytic fungi. The data from this work also document that the fungi are able to degrade further the main metabolites on the PCB pathway (i.e. chlorobenzoic acids) simultaneously with PCBs.     

Hydrogen production by catalytic aqueous-phase reforming of waste biomass: a review

Environmental Chemistry Letters - The rising adverse effects of climate change call for a rapid shift to low-carbon energy and reducing our dependence on fossil fuels. For that, biorefineries...     

Importance of conserving large and old trees to continuity of tree-related microhabitats

Protecting structural features, such as tree-related microhabitats (TreMs), is a cost-effective tool crucial for biodiversity conservation applicable to large forested landscapes. Although the development of TreMs is influenced by tree diameter, species, and vitality, the relationships between tree age and TreM profile remain poorly understood. Using a tree-ring-based approach and a large data set of 8038 trees, we modeled the effects of tree age, diameter, and site characteristics on TreM richness and occurrence across some of the most intact primary temperate forests in Europe, including mixed beech and spruce forests. We observed an overall increase in TreM richness on old and large trees in both forest types. The occurrence of specific TreM groups was variably related to tree age and diameter, but some TreM groups (e.g., epiphytes) had a stronger positive relationship with tree species and elevation. Although many TreM groups were positively associated with tree age and diameter, only two TreM groups in spruce stands reacted exclusively to tree age (insect galleries and exposed sapwood) without responding to diameter. Thus, the retention of trees for conservation purposes based on tree diameter appears to be a generally feasible approach with a rather low risk of underrepresentation of TreMs. Because greater tree age and diameter positively affected TreM development, placing a greater emphasis on conserving large trees and allowing them to reach older ages, for example, through the establishment of conservation reserves, would better maintain the continuity of TreM resource and associated biodiversity. However, this approach may be difficult due to the widespread intensification of forest management and global climate change.     

Advancing Energy Access Modelling with Geographic Information System Data

One of the main goals in pursuing sustainable development is to provide universal access to modern energy services, notably through the use of off-grid renewable energy technologies. To date, integrated assessment models (IAMs) poorly address energy access targets. In the context of research dedicated to energy scenarios and climate change mitigation in Africa, we attempt to advance the representation of energy access in one such IAM by using GIS data. In a case study for Ethiopia with the TIAM-ECN model, we demonstrate that by enriching an IAM with information derived from GIS databases, insights are obtained that better capture the dynamics of energy access developments, in comparison to conventional IAM analysis of energy technology deployment pathways. When duly accounting for the geographical spread in demography and technology costs in a developing country, we find that many people may gain access to electricity in remote areas thanks to the availability of affordable off-grid power production options that render expensive grid extensions unnecessary. This effect is not explicitly accounted for in most traditional IAMs. By the middle of the century, off-grid technologies could provide affordable electricity to 70% of the Ethiopian population, based almost entirely on renewable sources such as wind, solar and hydropower.