Validation of an evacuated canister method for measuring part-per-billion levels of chemical warfare agent simulants

The National Institute for Occupational Safety and Health (NIOSH) research on direct-reading instruments (DRIs) needed an instantaneous sampling method to provide independent confirmation of the concentrations of chemical warfare agent (CWA) simulants. It was determined that evacuated canisters would be the method of choice. There is no method specifically validated for volatile organic compounds (VOCs) in the NIOSH Manual of Analytical Methods. The purpose of this study was to validate an evacuated canister method for sampling seven specific VOCs that can be used as a simulant for CWA agents (cyclohexane) or influence the DRI measurement of CWA agents (acetone, chloroform, methylene chloride, methyl ethyl ketone, hexane, and carbon tetrachloride [CCl4]). The method used 6-L evacuated stainless-steel fused silica-lined canisters to sample the atmosphere containing VOCs. The contents of the canisters were then introduced into an autosampler/preconcentrator using a microscale purge and trap (MPT) method. The MPT method trapped and concentrated the VOCs in the air sample and removed most of the carbon dioxide and water vapor. After preconcentration, the samples were analyzed using a gas chromatograph with a mass selective detector. The method was tested, evaluated, and validated using the NIOSH recommended guidelines. The evaluation consisted of determining the optimum concentration range for the method; the sample stability over 30 days; and the accuracy, precision, and bias of the method. This method meets the NIOSH guidelines for six of the seven compounds (excluding acetone) tested in the range of 2.3-50 parts per billion (ppb), making it suitable for sampling of these VOCs at the ppb level.     

Particulate matter in new technology diesel exhaust (NTDE) is quantitatively and qualitatively very different from that found in traditional diesel exhaust (TDE)

Diesel exhaust (DE) characteristic of pre-1988 engines is classified as a "probable" human carcinogen (Group 2A) by the International Agency for Research on Cancer (IARC), and the U.S. Environmental Protection Agency has classified DE as "likely to be carcinogenic to humans." These classifications were based on the large body of health effect studies conducted on DE over the past 30 or so years. However, increasingly stringent U.S. emissions standards (1988-2010) for particulate matter (PM) and nitrogen oxides (NOx) in diesel exhaust have helped stimulate major technological advances in diesel engine technology and diesel fuel/lubricant composition, resulting in the emergence of what has been termed New Technology Diesel Exhaust, or NTDE. NTDE is defined as DE from post-2006 and older retrofit diesel engines that incorporate a variety of technological advancements, including electronic controls, ultra-low-sulfur diesel fuel, oxidation catalysts, and wall-flow diesel particulate filters (DPFs). As discussed in a prior review (T. W. Hesterberg et al.; Environ. Sci. Technol. 2008, 42, 6437-6445), numerous emissions characterization studies have demonstrated marked differences in regulated and unregulated emissions between NTDE and "traditional diesel exhaust" (TDE) from pre-1988 diesel engines. Now there exist even more data demonstrating significant chemical and physical distinctions between the diesel exhaust particulate (DEP) in NTDE versus DEP from pre-2007 diesel technology, and its greater resemblance to particulate emissions from compressed natural gas (CNG) or gasoline engines. Furthermore, preliminary toxicological data suggest that the changes to the physical and chemical composition of NTDE lead to differences in biological responses between NTDE versus TDE exposure. Ongoing studies are expected to address some of the remaining data gaps in the understanding of possible NTDE health effects, but there is now sufficient evidence to conclude that health effects studies of pre-2007 DE likely have little relevance in assessing the potential health risks of NTDE exposures.     

Characterizing long-term hydrologic-response and sediment-transport for the R-5 catchment

Recently there have been several calls to establish long-term data collection networks to monitor near-surface hydrologic response and landscape evolution. The focus of this paper is a long-term dataset from the International Hydrologic Decade (1965-1974). The small upland catchment, known as R-5, located near Chickasha, Olahoma, has been the subject of considerable attention within the event-based hydrologic modeling community for more than 30 yr. Here, for the first time, 8 yr of continuous near-surface hydrologic-response and sediment-transport data are analyzed to show trends in the catchment's long-term behavior. The datasets include precipitation, temperature, solar radiation, soil-water content, infiltration, water discharge, and sediment discharge. Potential and actual evapotranspiration rates were estimated and used to calculate an average annual water balance for the catchment. Findings include, for example, that rainfall intensity rarely exceeds the threshold for Horton-type runoff, soil-water content is both spatially and temporally variable, and the water and sediment discharge rates are positively correlated. The R-5 data provide a unique opportunity to test (and refine) process-based models of continuous hydrologic response and sediment transport at the catchment scale for applications in the emerging fields of hydroecology and hydrogeomorphology.     

Nitrogen fluxes through unsaturated zones in five agricultural settings across the United States

The main physical and chemical controls on nitrogen (N) fluxes between the root zone and the water table were determined for agricultural sites in California, Indiana, Maryland, Nebraska, and Washington from 2004 to 2005. Sites included irrigated and nonirrigated fields; soil textures ranging from clay to sand; crops including corn, soybeans, almonds, and pasture; and unsaturated zone thicknesses ranging from 1 to 22 m. Chemical analyses of water from lysimeters and shallow wells indicate that advective transport of nitrate is the dominant process affecting the flux of N below the root zone. Vertical profiles of (i) nitrogen species, (ii) stable isotopes of nitrogen and oxygen, and (iii) oxygen, N, and argon in unsaturated zone air and correlations between N and other agricultural chemicals indicate that reactions do not greatly affect N concentrations between the root zone and the capillary fringe. As a result, physical factors, such as N application rate, water inputs, and evapotranspiration, control the differences in concentrations among the sites. Concentrations of N in shallow lysimeters exhibit seasonal variation, whereas concentrations in lysimeters deeper than a few meters are relatively stable. Based on concentration and recharge estimates, fluxes of N through the deep unsaturated zone range from 7 to 99 kg ha(-1) yr(-1). Vertical fluxes of N in ground water are lower due to spatial and historical changes in N inputs. High N fluxes are associated with coarse sediments and high N application rates.     

Consolidation in an Individual Transferable Quota Regime: Lessons from New Zealand, 1986–1999

Market-based approaches to environmental regulation (such as tradable permits or transferable quotas) are frequently offered as innovative solutions to many environmental problems. Globally, one of the most well-established forms of this approach is individual transferable quotas (or ITQs) in fisheries management. Within the natural resource management community, there is considerable debate over the effects ITQs have on the fishing industry and fisher behavior although this approach is not well-established in the United States. The previously imposed moratorium on ITQs in the United States has expired and the 2006 reauthorization of the Magnuson-Stevens Act explicitly provides for limited access privileges (LAPs). A variety of fishers, regulators, and conservation organizations are enthusiastically seeking to introduce ITQ management. With debate over whether and how ITQs should be used in American fisheries reinvigorated, it is timely to examine the evidence on the social and economic effects of ITQs in other nations’ fisheries. After briefly summarizing the debate on ITQs, we examine the case of New Zealand, one of the earliest and longest-lived ITQ-based fisheries regimes. We use multiple data sources and methods to analyze the extent to which industry consolidation and aggregation has occurred, including surveys of industry participants, expert interviews, reviews of academic reports and analyses, analysis of trade publications, and direct analysis of quota ownership patterns. This analysis shows a more complex outcome than recent debates in the ITQ literature would predict. These findings suggest that policy makers considering ITQs can learn from the experiences of other countries related to key issues such as quota allocation, aggregation limits, transferability, cost recovery, and resource sustainability when designing ITQ and other LAP systems. It is also important to explicitly identify economic and social objectives and then carefully design ITQ regimes to meet these objectives.     

Application of an Environmental Decision Support System to a Water Quality Trading Program Affected by Surface Water Diversions

Environmental decision support systems (EDSSs) are an emerging tool used to integrate the evaluation of highly complex and interrelated physicochemical, biological, hydrological, social, and economic aspects of environmental problems. An EDSS approach is developed to address hot-spot concerns for a water quality trading program intended to implement the total maximum daily load (TMDL) for phosphorus in the Non-Tidal Passaic River Basin of New Jersey. Twenty-two wastewater treatment plants (WWTPs) spread throughout the watershed are considered the major sources of phosphorus loading to the river system. Periodic surface water diversions to a major reservoir from the confluence of two key tributaries alter the natural hydrology of the watershed and must be considered in the development of a trading framework that ensures protection of water quality. An EDSS is applied that enables the selection of a water quality trading framework that protects the watershed from phosphorus-induced hot spots. The EDSS employs Simon’s (1960) three stages of the decision-making process: intelligence, design, and choice. The identification of two potential hot spots and three diversion scenarios enables the delineation of three management areas for buying and selling of phosphorus credits among WWTPs. The result shows that the most conservative option entails consideration of two possible diversion scenarios, and trading between management areas is restricted accordingly. The method described here is believed to be the first application of an EDSS to a water quality trading program that explicitly accounts for surface water diversions.     

Anti-biofilm Activity of Solvent-Cast and Electrospun Polyhydroxyalkanoate Membranes Treated with Lysozyme

Biofilms consist of groups of microorganisms that adhere to surfaces, such as wound and implant surfaces, making it difficult to prevent or remove their formation by antibiotic treatment, due to the innate resistance of the biofilm. Effective treatments of medical biofilms are limited. Polyhydroxyalkanoate (PHA) is a biodegradable and biocompatible polymer that is a suitable alternative to petroleum based polymers for use as a raw material for medical applications. In this study, membranes of the copolymer poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(HB-co-HHx)] containing different HHx monomer contents were used due to its porosity and flexibility, and different sheets were prepared by solvent-casting and electrospinning methods. The sheets were loaded with lysozyme in order to measure the maximum amount of protein adsorption and to examine the ability of immobilized enzyme to inhibit biofilm formation and detach previously established biofilms. Our results have shown maximum loading of 16.1 µg enzyme per 9.5 mm³ discs, and these sheets are effective for inhibiting biofilm formation. Also, lysozyme loaded, eletrospun sheets were observed to more effectively inhibit biofilm formation, as compared to solvent-cast sheets. Based on this study, P(HB-co-HHx) sheets are a suitable material for being used as a potential raw material for fabrication of wound dressings to be used in anti-biofilm treatments.     

Creating sustainable communities: skills and learning in Ontario’s small urban municipalities

This article presents the pilot study results of a province-wide survey of skills and learning in sustainable community development in Ontario, Canada. The pilot project focuses on the testing of an online survey to examine skills building for creating sustainable communities in Ontario’s small urban municipalities. The survey examined the generic, technical and specialist skills, whether they are skills already acquired and/or required by professionals and practitioners for creating sustainable communities. The survey targeted 74 small urban municipalities and 300 respondents by profession. Building sustainable communities require ‘upskilling’ of the workforce as it poses a challenge to those hoping to make a real progress and development at the local level.     

Is pork trade good for China's greenhouse gas emissions?

China produces the largest amount of pork in the world, which emits the largest amount of greenhouse gases (GHGs). This paper calculates GHG emissions from China’s hog production at the provincial level using newly published emission factors. Empirical results show that GHG emissions from China’s hog production mainly respond to the scale intensity. Capital abundance and income contribute positively to GHG emissions from hog production. Pork trade increases GHG emissions from China’s hog production with a significantly direct effect, reduces GHG emissions through indirect technique effects.