Molecular tools for bathing water assessment in Europe: Balancing social science research with a rapidly developing environmental science evidence-base

The use of molecular tools, principally qPCR, versus traditional culture-based methods for quantifying microbial parameters (e.g., Fecal Indicator Organisms) in bathing waters generates considerable ongoing debate at the science–policy interface. Advances in science have allowed the development and application of molecular biological methods for rapid (~2 h) quantification of microbial pollution in bathing and recreational waters. In contrast, culture-based methods can take between 18 and 96 h for sample processing. Thus, molecular tools offer an opportunity to provide a more meaningful statement of microbial risk to water-users by providing near-real-time information enabling potentially more informed decision-making with regard to water-based activities. However, complementary studies concerning the potential costs and benefits of adopting rapid methods as a regulatory tool are in short supply. We report on findings from an international Working Group that examined the breadth of social impacts, challenges, and research opportunities associated with the application of molecular tools to bathing water regulations.     

An investigation on the fuel savings potential of hybrid hydraulic refuse collection vehicles

Refuse trucks play an important role in the waste collection process. Due to their typical driving cycle, these vehicles are characterized by large fuel consumption, which strongly affects the overall waste disposal costs. Hybrid hydraulic refuse vehicles offer an interesting alternative to conventional diesel trucks, because they are able to recuperate, store and reuse braking energy. However, the expected fuel savings can vary strongly depending on the driving cycle and the operational mode. Therefore, in order to assess the possible fuel savings, a typical driving cycle was measured in a conventional vehicle run by the waste authority of the City of Stuttgart, and a dynamical model of the considered vehicle was built up. Based on the measured driving cycle and the vehicle model including the hybrid powertrain components, simulations for both the conventional and the hybrid vehicle were performed. Fuel consumption results that indicate savings of about 20% are presented and analyzed in order to evaluate the benefit of hybrid hydraulic vehicles used for refuse collection.     

An Aquifer Classification System and Geographical Information System-Based Analysis Tool for Watershed Managers in the Western U.S.1

Payne, Scott M. and William W. Woessner, 2010. An Aquifer Classification System and Geographical Information System-Based Analysis Tool for Watershed Managers in the Western U.S. Journal of the American Water Resources Association (JAWRA) 46(5):1003-1023. DOI: 10.1111/j.1752-1688.2010.00472.x Abstract: Aquifers and groundwater systems can be classified using a variety of independent methods to characterize geologic and hydraulic properties, the degree of connection with surface water, and geochemical conditions. In light of a growing global demand for water, an approach for classifying groundwater systems at the watershed scale is needed. A comprehensive classification system is proposed that combines recognized methods and new approaches. The purpose of classification is to provide groundwater professionals, policy makers, and watershed managers with a widely applicable and repeatable system that reduces sometimes cumbersome complex databases and analyzes to straightforward terminology and graphical representations. The proposed classification system uses basin geology, aquifer productivity, water quality, and the degree of groundwater/surface water connection as classification criteria. The approach is based on literature values, reference databases, and fundamental hydrologic and hydrogeologic principles. The proposed classification system treats dataset completeness as a variable and includes a tiered assessment protocol that depends on the quality and quantity of data. In addition, it assembles and catalogs groundwater information using a consistent set of nomenclature. It is designed to analyze and display results using Geographical Information System mapping tools.     

interpretation of air quality data with respect to the national ambient air quality standards

San Diego Gas &; Electric has developed a quality assurance program for continuous emission monitors (CEM). Extractive, rather than in situ, monitors were selected as a result of an in-house evaluation program. Two extractive systems have been certified and a good operating and maintenance record has been established on these systems. A successful program requires the involvement and support of all affected personnel. It is desirable to have one or two key personnel coordinate the development of the program. It is also highly desirable to have good in-house source testing capabilities.     

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A technique is developed to compute precision requirements for component parts of an emissions inventory to ensure (at a given confidence level) an overall acceptable precision in the estimate of total emissions. Since the emissions inventory is a basic requirement of air quality control implementation plans and provides a valuable management tool for planning air pollution control activities, it isi appropriate to state in quantitative terms the confidence that can be associated with each inventory. The approach reported here uses weighted sensitivity analysis methods to distribute both percentage and physical errors in source class emissions according to their contribution to the total emissions, and utilizes Chebyshev’s inequality to establish confidence levels for total emissions. The analysis has been extended to cover the case where one or more of the error components in a given inventory source class can be fixed by the analyst. The utility of the technique is manifold and several practical applications are reported. In particular, it serves to establish percentage error requirements for source categories to satisfy given error bounds for the overall emissions inventory at a given level of statistical confidence. The weighted sensitivity analysis technique possesses a high degree of generality, being applicable to compute component error requirements for any kind of data inventory which exhibits a hierarchical (tree-like) structure, as exemplified by NEDS Emissions Summary Reports. This work should be of interest to air pollution control planners at all levels of government and to anyone responsible for the air pollution portion of environmental impact statements.     

Tolerating an infection: an indirect benefit of co-founding queen associations in the ant Lasius niger

Pathogens exert a strong selection pressure on organisms to evolve effective immune defences. In addition to individual immunity, social organisms can act cooperatively to produce collective defences. In many ant species, queens have the option to found a colony alone or in groups with other, often unrelated, conspecifics. These associations are transient, usually lasting only as long as each queen benefits from the presence of others. In fact, once the first workers emerge, queens fight to the death for dominance. One potential advantage of co-founding may be that queens benefit from collective disease defences, such as mutual grooming, that act against common soil pathogens. We test this hypothesis by exposing single and co-founding queens to a fungal parasite, in order to assess whether queens in co-founding associations have improved survival. Surprisingly, co-foundresses exposed to the entomopathogenic fungus Metarhizium did not engage in cooperative disease defences, and consequently, we find no direct benefit of multiple queens on survival. However, an indirect benefit was observed, with parasite-exposed queens producing more brood when they co-founded, than when they were alone. We suggest this is due to a trade-off between reproduction and immunity. Additionally, we report an extraordinary ability of the queens to tolerate an infection for long periods after parasite exposure. Our study suggests that there are no social immunity benefits for co-founding ant queens, but that in parasite-rich environments, the presence of additional queens may nevertheless improve the chances of colony founding success.     

Hydraulic response and nitrogen retention in bioretention mesocosms with regulated outlets: part II--nitrogen retention

We observed dissolved nitrogen retention in vegetated bioretention mesocosms using different media with varying hydraulic conductivities. Elevated outlets were installed to regulate hydraulic response, with one treatment left free draining. The treatments (three replicates each) were loaded weekly with 50 cm of effluent averaging 2.47 mg/L nitrogen oxides (NOx) and 4.67 mg/L total nitrogen for 1 year. The NOx and total nitrogen retention by the outlet regulated treatments was significantly greater than the unregulated treatment. The systems then were dosed 6 times with 53 cm of synthetic stormwater averaging 0.77 mg/ L NOx and 1.46 mg/L total nitrogen, applied over 90 minutes. The outlet regulated treatment retained 68% NOx and 60% total nitrogen, while the corresponding free draining treatment retained 25% NOx and 27% total nitrogen. Over the following winter, the outlet regulated treatment retained 50% NOx and 73% total nitrogen, while the corresponding free draining treatment exported 17% more NOx, while retaining 50% total nitrogen.     

Transport and retention of Cryptosporidium parvum oocysts in sandy soils

A series of miscible-displacement experiments was conducted to examine the retention and transport behavior of oocysts in natural porous media. Three soils and a model sand were used that differed in physical and geochemical properties. Transport behavior was examined under various treatment conditions to help evaluate retention mechanisms. Significant retention of oocysts was observed for all media despite the fact that conditions were unfavorable for physicochemical interactions with respect to DLVO theory. The magnitude of retention was not influenced significantly by alterations in solution chemistry (reduction in ionic strength) or soil surface properties (removal of soil organic matter and metal oxides). On the basis of the observed results, it appears that retention by secondary energy minima or geochemical microdomains was minimal for these systems. The porous media used for the experiments exhibited large magnitudes of surface roughness, and it is suggested that this surface roughness contributed significantly to oocyst retention.     

Support for maternal manipulation of developmental nutrition in a facultatively eusocial bee, <Emphasis Type="Italic">Megalopta genalis</Emphasis> (Halictidae)

Developmental maternal effects are a potentially important source of phenotypic variation, but they can be difficult to distinguish from other environmental factors. This is an important distinction within the context of social evolution, because if variation in offspring helping behavior is due to maternal manipulation, social selection may act on maternal phenotypes, as well as those of offspring. Factors correlated with social castes have been linked to variation in developmental nutrition, which might provide opportunity for females to manipulate the social behavior of their offspring. Megalopta genalis is a mass-provisioning facultatively eusocial sweat bee for which production of males and females in social and solitary nests is concurrent and asynchronous. Female offspring may become either gynes (reproductive dispersers) or workers (non-reproductive helpers). We predicted that if maternal manipulation plays a role in M. genalis caste determination, investment in daughters should vary more than for sons. The mass and protein content of pollen stores provided to female offspring varied significantly more than those of males, but volume and sugar content did not. Sugar content varied more among female eggs in social nests than in solitary nests. Provisions were larger, with higher nutrient content, for female eggs and in social nests. Adult females and males show different patterns of allometry, and their investment ratio ranged from 1.23 to 1.69. Adult body weight varied more for females than males, possibly reflecting increased variation in maternal investment in female offspring. These differences are consistent with a role for maternal manipulation in the social plasticity observed in M. genalis.