IMPACTS FROM DITCHING SALT MARSHES IN THE MID-ATLANTIC AND NORTHEASTERN UNITED STATES

Tidal inundation extent and duration, and water drainage and retention by marsh peat – marsh hydrology – determine most physical and ecological characteristics of salt marsh systems. Ditching, installed across nearly all marshes on the US East Coast by 1940 to control mosquitoes, alters marsh hydrology. Two linchpin papers are used here as springboards to review the literature that describes the resulting effects, which clearly include reduced water table height for most marshes and changes in avian populations. Effects on invertebrate populations, including mosquitoes, are generally less, although to a smaller degree than is sometimes reported. Impacts on nekton are not clear, although probably negative. Tidal range and the degree of tide asymmetry appear to have greater effects on inter-marsh variations in effects from ditching than has generally been appreciated or studied. Overall, although changed patterns of nutrient releases and promotion of Phragmites australis invasions are important ecological effects extending beyond individual sites, and salt marsh aesthetics are marred, ditching impacts are less than certain other anthropogenic alterations of coastal processes that affect salt marshes and estuarine ecology to a much greater extent

A Classification Methodology for Landfill Leachates

A characterization scheme based on landfill leachate chemical signatures could support studies of leachate evolution over time, liner performance, and help confirm or disprove potential leachate contamination of groundwater. Wide variations in single constituents across time, sites, and site practices, and inconsistencies related to common bivariate measures suggest a robust, multivariate analysis could be useful. A variant Stiff diagram approach (a subjective analytical comparison of soluble salts) has been developed, and supports graphical depictions of multiple samples. The hypothesis is that leachates with similar chemistry form clusters, and this was tested using a data set of 652 samples from 26 distinct liner systems collected from a Long Island (New York, USA) landfill over more than 20 years. Most (75%) of diagrams were classified into three general leachate groupings that associated with the kinds of wastes received in the particular landfill module (90% if early leachate results are not considered)

Estimates of Worst Case Baseline West Nile Virus Disease Effects in a Suburban New York County

Serosurveys conducted where West Nile Virus (WNV) caused health impacts were used to construct a model of potential worst case health impacts in a suburban setting. This model addressed two common public perceptions regarding mosquito control activities and WNV disease: it is not a disease of major consequence, and exposed populations quickly become immune. Comparisons to blood bank infection and serious disease incidence data were similar to some of the serosurvey model results. Accounting for theoretical increasing immunity, even over a 20-year horizon, did not substantially reduce the potential impacts. The model results were approximately an order of magnitude greater than those actually experienced in Suffolk County, New York; differences in mosquito populations and/or the degree of mosquito control between Suffolk County and serosurvey sites seem to be the cause of the differences

MODELING AN IMPROVEMENT IN PHOSPHORUS UTILIZATION IN TROPICAL AGRICULTURE

Studies of Terra Preta soils have generated interest in recreating their fertility elsewhere. Much of the research has focused on soil amendment charcoal (“biochar”). Terra Preta also contains bone fragments, producing a high concentration of phosphorus. Some forecast worldwide declines in phosphorus supplies, and better agricultural system management is required to improve phosphorus use efficiency. A conceptual model is offered to consider the influence of charcoal on bioavailability of phosphorus. The model describes a system where improvements in the chemical and biological condition of the soil result in increased phosphorus availability and cycling. Mechanisms of phosphorus/charcoal interaction are considered, and an assessment is made of the potential impact on African subsistence agriculture from the incorporation of biogenic, allogenic phosphorus through biochar

A Review of the Hyporheic Zone, Stream Restoration, and Means to Enhance Denitrification

The hyporheic zone is the subsurface area below and adjacent to a stream where groundwater mixes with stream water, through vertical, lateral, and longitudinal flows. The hyporheic zone connects the stream to uplands and other terrestrial environments. It is a zone of distinct faunal communities, high biological diversity and ecological complexity, and is the site of chemical processing and transformations of ground- and stream waters. The hyporheic zone is important to the overall ecosystem ecology of the stream, and it can influence stream water chemistry. Flows, reactions, and biota in the hyporheic zone are heterogeneous and patchy, making it difficult to clearly describe the ecotone in a straightforward, general way. Nitrogen processing, especially denitrification, appears to be widespread in the hyporheic zone. The hyporheic zone, as with most aquatic systems, is often impacted by human activities. Stream restorations rarely consider potential effects on the hyporheic zone, but careful project choices can enhance the condition of the hyporheic zone, and so increase uptake of nitrogen by stream-associated environments as partial mitigation of continuing and increasing releases of reactive nitrogen, potentially reaping short-term benefits to estuarine environments that might not be as quickly realized from source control measures

COST EFFECTIVENESS OF RECYCLING: A SYSTEMS MODEL

Financial analytical models of waste management systems have often found that recycling costs exceed direct benefits, and in order to economically justify recycling activities, externalities such as household expenses or environmental impacts must be invoked. Certain more empirically based studies have also found that recycling is more expensive than disposal. Other work, both through models and surveys, have found differently. Here we present an empirical systems model, largely drawn from a suburban Long Island municipality. The model accounts for changes in distribution of effort as recycling tonnages displace disposal tonnages, and the seven different cases examined all show that curbside collection programs that manage up to between 31% and 37% of the waste stream should result in overall system savings. These savings accrue partially because of assumed cost differences in tip fees for recyclables and disposed wastes, and also because recycling can result in a more efficient, cost-effective collection program. These results imply that increases in recycling are justifiable due to cost-savings alone, not on more difficult to measure factors that may not impact program budgets

Energy Assessment of Smithtown, New York

Energy management and carbon mitigation plans, often created to address global issues, must be implemented locally. Each specific area has its own needs and problems. For this study, we used publicly available data to create an energy assessment for the Town of Smithtown, a municipality of 116,000 people on the north shore of Long Island (New York). We found that motor vehicles consume the largest amount of energy, followed by space heating for both residential and commercial-industrial purposes. Local policies probably can only modestly affect transportation energy use, although federal policies may have significant effects over the next several decades. A local renovation financing program holds great promise to improve residential heating energy usage, and could greatly reduce energy consumption if it is expanded to cover the commercial sector. Current Town programs have begun to address immediate needs, although programs will require revision to achieve major reductions in energy use

Multi-Model Validity Assessment of Groundwater Flow Simulation Models Using Area Metric Approach

We demonstrate the application of the Area Metric developed by Ferson et al. (2008) for multi-model validity assessment. The Area Metric quantified the degree of models’ replicative validity: the degree of agreement between the observed data and the corresponding simulated outputs represented as their empirical cumulative distribution functions (ECDFs). This approach was used to rank multiple representations of a case study groundwater flow model of a landfill by their Area Metric scores. A multi-model approach allows for the accounting for uncertainties that may either be epistemic (from lack of knowledge), or aleatory (from variability inherent in the system). The Area Metric approach enabled explicit incorporation of model uncertainties, epistemic as well as aleatory, into validation assessment. The proposed approach informs understanding of the collected data and that of the model domain. It avoids model overfitting to a particular system state, and in fact is a blind assessment of the models’ validity: models are not adjusted, or updated, to improve their fit. This approach assesses the degree of models’ validity, in place of the typical binary model validation/invalidation process. Collectively, this increases confidence in the model’s representativeness that in turn, reduces risks to model users

A Management Framework for Municipal Solid Waste Systems and its Application to Food Waste prevention

Waste management is a complex task involving numerous waste fractions, a range of technological treatment options, and many outputs that are circulated back to society. A systematic, interdisciplinary systems management framework was developed to facilitate the planning, implementation, and maintenance of sustainable waste systems. It aims not to replace existing decision-making approaches, but rather to enable their integration to allow for inclusion of overall sustainability concerns and address the complexity of solid waste management. The framework defines key considerations for system design, steps for performance monitoring, and approaches for facilitating continual system improvements. It was developed by critically examining the literature to determine what aspects of a management framework would be most effective at improving systems management for complex waste systems. The framework was applied to food waste management as a theoretical case study to exemplify how it can serve as a systems model for complex waste systems, as well as address obstacles typically faced in the field. Its benefits include the integration of existing waste assessment models; the inclusion of environmental, economic, and social priorities; efficient performance monitoring; and a structure to continuously define, review, and improve systems. This framework may have broader implications for addressing sustainability in other disciplines

Degradable Plastics and their Potential to Affect Solid Waste Systems

Plastic waste forms a substantial part of municipal solid waste and has caused environmental concerns, particularly due to chemical contamination of the environment and effects from persistent litter. Plastics also complicate waste management processes, such as by having poor recovery rates through recycling, and causing contamination in composting operations. One potential means to address some of these challenges is through degradable plastics which, unlike conventional plastics, are designed to decompose at an accelerated rate in specific environments. Degradable plastics aim to address the end-of-life of plastic products and are intended to reduce the environmental impacts associated with their use and management. The first generation of degradable plastics did not meet marketing claims; some of the more recent formulations, partly as a consequence of third party certifications, are more compliant. However, many plastics that are labelled as degradable do not decompose very readily, and it is not clear that litter will be diminished to any great degree through their use. In addition, user confusion regarding degradable definitions is common. Multiple formulations mean not all degradable plastics address compost contamination, and most degradable plastics do not address other problems associated with plastics waste management. Therefore it is not clear that degradable plastics constitute a major technological advance. In fact, they may be more harmful than helpful to waste management systems at this time. Here we discuss how these materials perform in different aspects of solid waste programs: recycling, composting, WTE incineration, and landfills, as well as the potential for these plastics to reduce litter problems, both on land and at sea