Response of Nitrogen Loading to the Chesapeake Bay to Source Reduction and Land Use Change Scenarios: A SPARROW‐Informed Analysis

In response to concerns regarding the health of streams and receiving waters, the United States Environmental Protection Agency established a total maximum daily load for nitrogen in the Chesapeake Bay watershed for which practices must be in place by 2025 resulting in an expected 25% reduction in load from 2009 levels. The response of total nitrogen (TN) loads delivered to the Bay to nine source reduction and land use change scenarios was estimated using a Spatially Referenced Regression on Watershed Attributes model. The largest predicted reduction in TN load delivered to the Bay was associated with a scenario in which the mass of TN as fertilizer applied to agricultural lands was decreased. A 25% decrease in the mass of TN applied as fertilizer resulted in a predicted reduction in TN loading to the Bay of 11.3%, which was 2.5–5 times greater than the reductions predicted by other scenarios. Eliminating fertilizer application to all agricultural land in the watershed resulted in a predicted reduction in TN load to the Bay of 45%. It was estimated that an approximate 25% reduction in TN loading to the Bay could be achieved by eliminating fertilizer applied to the 7% of subwatersheds contributing the greatest fertilizer‐sourced TN loads to the Bay. These results indicate that management strategies aimed at decreasing loading from a small number of subwatersheds may be effective for reducing TN loads to the Bay, and similar analyses are possible in other watersheds.     

Use of surrogate species to cost-effectively prioritize conservation actions

Conservation efforts often focus on umbrella species whose distributions overlap with many other flora and fauna. However, because biodiversity is affected by different threats that are spatially variable, focusing only on the geographic range overlap of species may not be sufficient in allocating the necessary actions needed to efficiently abate threats. We developed a problem-based method for prioritizing conservation actions for umbrella species that maximizes the total number of flora and fauna benefiting from management while considering threats, actions, and costs. We tested our new method by assessing the performance of the Australian federal government's umbrella prioritization list, which identifies 73 umbrella species as priorities for conservation attention. Our results show that the federal government priority list benefits only 6% of all Australia's threatened terrestrial species. This could be increased to benefit nearly half (or 46%) of all threatened terrestrial species for the same budget of AU$550 million/year if more suitable umbrella species were chosen. This results in a 7-fold increase in management efficiency. We believe nations around the world can markedly improve the selection of prioritized umbrella species for conservation action with this transparent, quantitative, and objective prioritization approach.     

Studies on the drug resistance profile of Enterococcus faecium distributed from poultry retailers to hospitals

The multidrug resistant Enterococcus faecium (MEF) strains originating from farm animals are proliferating at a substantial pace to impact downstream food chains and could reach hospitals. This study was conducted to elucidate the drug susceptibility profile of MEF strains collected from poultry products in Ann Arbor, MI area and clinical settings from Michigan State Lab and Moffitt Cancer Center (MCC) in Florida. Presumptive positive Enterococcus isolates at species level were identified by Matrix Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) analysis. The antibiotic susceptibility profile for both poultry and clinical strains was determined by the Thermo Scientific's Sensititre conform to the National Committee for Clinical Laboratory Standards (NCCLS) and validated via quantitative real-time PCR (qPCR) methods. Out of 50 poultry samples (Turkey: n = 30; Chicken: n = 20), 36 samples were positive for Enterococcus species from which 20.83% were identified as E. faecium. All the E. faecium isolates were multidrug resistant and displayed resistance to the last alternative drug, quinupristin/dalfopristin (QD) used to treat vancomycin resistant E. faecium (VRE) in hospitals. Results indicate the presence of MEF strains in food animals and clinical settings that are also resistant to QD.     

Exploring the origins of ‘social license to operate’ in the mining sector: Perspectives from governance and sustainability theories

In the mining sector, local communities have emerged as particularly important governance actors. Conventional approaches to mineral development no longer suffice for these communities, which have demanded a greater share of benefits and increased involvement in decision making. These trends have been spurred by the growth of the sustainable development paradigm and governance shifts that have increasingly transferred governing authority towards non-state actors. Accordingly, there is now widespread recognition that mineral developers need to gain a ‘social license to operate’ (SLO) from local communities in order to avoid potentially costly conflict and exposure to social risks. A social license can be considered to exist when a mining project is seen as having the ongoing approval and broad acceptance of society to conduct its activities. Due to the concept's relatively recent emergence, however, only a limited body of scholarship has developed around SLO. Drawing on examples from northern Canada, this paper uses governance and sustainability theories to conceptualize the origins of SLO in the mining sector and describe some of the associated implications. Further research is needed to determine governance arrangements which help facilitate establishment of SLO in different mineral development contexts.     

Ecological footprints and shadows in an urban estuary, Narragansett Bay, RI (USA)

Because the rise of cities in North America was much later than in many other parts of the world, their connections to the hinterland were influenced early in their development by railroads and steam-powered water transport. These fossil fuel-based links made it possible to widely separate the ??upstream?? autotrophic supporting systems from the heterotrophic cities. Here, we take a different look at the connection between a city (Providence, RI, USA) and its supporting natural systems by focusing on the export of industrial and metabolic wastes from the city to the ??downstream?? coastal ecosystem in Narragansett Bay. In this way, we can track the history of a city by examining the concentrations of nutrients, metals, and hydrocarbons in the water and sediments of the estuary. In the greater Providence metropolitan area at the head of Narragansett Bay, there was rapid population and industrial expansion during the 1800s without the proper infrastructure to deal with water supply for public safety and health. On the other hand, the absence of a public water supply kept industrial and metabolic wastes largely on land. However, from the fall of 1871, on with the construction of a public water supply and sewer system, human wastes began flowing into the estuary. By reconstructing the historical record of metals and other pollutants, we illustrate clear temporal and spatial gradients of urban impact on the bay. Unfortunately, while numerous studies during the 1970s and 1980s focused on documenting metal and hydrocarbon pollution in the bay, there has been little effort to quantify the impact of mitigation efforts that have greatly reduced the input of metals and hydrocarbons to the system. Nutrient reductions are more recent and ongoing.     

Disaster risk reduction capacity assessment for precarious settlements in Guatemala City

This study presents findings of an institutional capacity analysis of urban disaster risk reduction for informal settlements in the Guatemala Metropolitan Region. It uses a resource access perspective of vulnerability, actor-network theory, and qualitative data collection. The analysis reveals that there is interest in disaster risk reduction for the informal settlements; however, there is little in the way of direct financial or oversight relationships between informal settlement residents and all other actors. Respondents observed that informal settlements would probably remain inhabited; thus, there is a need for disaster risk reduction within these settlements. Disaster risk reduction capacity for informal settlements exists and can be further leveraged, as long as steps are taken to ensure appropriate access to and control of resources and oversight. Further, the nascent institutional arrangements should be strengthened through increased communication and coordination between actors, a decentralization of oversight and financial relationships, and mediation of identified resource conflicts.     

Modeling Evidence of Incloud Transformation Of Sulfur Dioxide to Sulfate

Methylene chloride (CH₂Cl₂) is presently under study by the U.S. EPA and other agencies to determine if the compound presents an unreasonable risk to human health and to determine if regulatory action is needed to reduce the risk. This paper describes one portion of the study which required the development and validation of a method of sampling and analysis for source emission measurements.

Prior to source sampling, laboratory experiments were conducted to determine the best sample container in which to collect an integrated sample. It was found that CH₂Cl₂ remained stable in Tedlar bags for at least four weeks. The analytical method selected was gas chromatography with flame ionization detection (GC/FID). During the field portion of the study, both manufacturer and user emission sources of CH₂Cl₂ were tested. Multiple sets of simultaneous quadruplicate bag samples were collected to determine the precision of both sampling and analysis in the field. All samples were analyzed at the test site after collection and then returned to Research Triangle Park. Samples were subsequently reanalyzed in the laboratories of Radian and the U.S. EPA using three GC/FID instruments and two types of GC columns. The range of concentrations from the sources was 100 ppm to 27,000 ppm CH₂Cl₂. A statistical analysis of samples collected simultaneously showed no difference in the samples, proving good precision In both sampling and analysis. Some of the sample bags returned from the test sites developed leaks indicating that immediate on-site analysis is best. A comparison of results obtained in the field and the two laboratories showed that interand intra-laboratory precision was within 10 percent.     

A Strategy and Methodology for Defensibly Correlating Spilled Oil to Source Candidates

The source of crude oils and petroleum products released into navigable waterways and shipping lanes is not always known. Thus, the defensible identification of spilled crude oils and petroleum products and their correlation to suspected sources is a critical part of many oil spill assessments. Quantitative "fingerprinting" analysis, when evaluated using straightforward statistical and numerical analyses, provides a defensible means to differentiate among qualitatively similar oils and provides the best assessment of the source(s) for spilled oils. Polycyclic aromatic hydrocarbon (PAH) and petroleum biomarker concentration data are a particularly useful quantitative measure that can benefit most oil spill investigations. In this paper the strategy and methodology for correlation analysis that relies upon quantitative gas chromatography/mass spectrometry operated in the selected ion monitoring mode (GC/MS-SIM) is demonstrated in a case study involving 66 candidate sources for a heavy fuel oil spill of unknown origin. The strategy includes identification of 19 chemical indices (out of 45 evaluated) based upon PAH's and biomarkers that were (1) independent of weathering; and (2) precisely measured, both of which are determined by statistical analysis of the data. The 19 chemical indices meeting these criteria are subsequently analysed using principal component analysis (PCA), which helps to determine defensibly the "prime suspects" for the oil spill under investigation. The strategy and methodology described, which combines statistical and numerical analysis of quantitative chemical data, can be adapted and applied to other environmental forensic investigations with the objective of correlating any form of contamination to its suspected sources.     

Effect of Interfacial Modifiers on Mechanical and Physical Properties of the PHB Composite with High Wood Flour Content

To explore the commercial viability of Polyhydroxybutyrate (PHB)/wood flour (WF) composites, systems were produced at industry-standard levels of fiber loading. Further, four interfacial modifiers were selected to improve the mechanical properties of PHB/WF composites, including maleated PHB (PHB-g-MA), a low molecular weight epoxy, a low molecular weight polyester, and polymethylene-diphenyl-diisocyante (pMDI). Results showed that all modifiers resulted in improvements in tensile strength and modulus, however, pMDI showed the highest improvements. The pMDI modifier also improved water uptake of the composites. Study of the fracture surfaces showed signs of improved fiber bonding, as did morphological studies by dynamic mechanical analysis (DMA), and differential scanning calorimetry (DSC). Interpretation of the DSC and DMA results indicate possible reactions with lubricant, and interactions between PHB and wood fibers with the addition of pMDI.