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BACKGROUND: Turbidity has been used as an indicator of microbiological contamination of drinking water in time-series studies attempting to discern the presence of waterborne gastrointestinal illness; however, the utility of turbidity as a proxy exposure measure has been questioned. OBJECTIVES: We conducted a review of epidemiological studies of the association between turbidity of drinking-water supplies and incidence of acute gastrointestinal illness (AGI), including a synthesis of the overall weight of evidence. Our goal was to evaluate the potential for causal inference from the studies. METHODS: We identified 14 studies on the topic (distinct by region, time period and/or population). We evaluated each study with regard to modeling approaches, potential biases, and the strength of evidence. We also considered consistencies and differences in the collective results. DISCUSSION: Positive associations between drinking-water turbidity and AGI incidence were found in different cities and time periods, and with both unfiltered and filtered supplies. There was some evidence for a stronger association at higher turbidity levels. The studies appeared to adequately adjust for confounding. There was fair consistency in the notable lags between turbidity measurement and AGI identification, which fell between 6 and 10 d in many studies. CONCLUSIONS: The observed associations suggest a detectable incidence of waterborne AGI from drinking water in the systems and time periods studied. However, some discrepant results indicate that the association may be context specific. Combining turbidity with seasonal and climatic factors, additional water quality measures, and treatment data may enhance predictive modeling in future studies. [ABSTRACT FROM AUTHOR]

Flowback water is the solution that returns to the surface following completion of the hydraulic fracturing process during natural gas extraction. This study examines and analyzes the constituents that make up flowback waters collected from various drilling sites in Marcellus shale formation in the states of Pennsylvania, New York, and West Virginia. Flowback sampling data were collected from four different sources (the Environmental Protection Agency, Gas Technology Institute; Pennsylvania Department of Environmental Protection; Bureau of Oil and Gas Management; and the New York Department of Environmental Conservation) and compiled into one database with a total of 35,000 entries. Descriptive statistical analysis revealed high concentrations of chlorinated solvents, disinfectants, dissolved metals, organic compounds, radionuclides, and total dissolved solids. A one-way ANOVA test revealed that over 60% of the constituents tested displayed significant differences (significance level = 0.05) in mean concentrations among the four data sources. Relative prioritization scores were developed for 58 constituents by dividing observed mean concentrations by the maximum contamination level (MCL) guidelines for drinking water. The following constituents were found to have mean concentrations over 10 times greater than the MCL: 1,2-dichloroethane, antimony, barium, benzene, benzo(a)pyrene, chloride, dibromochloromethane, gross alpha, iron, manganese, pentachlorophenol, radium, and thallium, and vinyl chloride. Concentrations of anthropogenic chemicals are tightly correlated with each other, but not with chloride concentrations, and not with naturally occurring inorganics and radionuclides. [ABSTRACT FROM AUTHOR]

In this study, a Bayesian framework was applied to update a model of pathogen fate and transport in the indoor environment. Distributions for model parameters (e.g., release quantity of B. anthracis spores, risk of illness, spore setting velocity, resuspension rate, sample recovery efficiency, etc.) were updated by comparing model predictions with measurements of B. anthracis spores made after one of the 2001 anthrax letter attacks. The updating process, which was implemented by using Markov chain Monte Carlo (MCMC) methods, significantly reduced the uncertainties of inputs with uniformed prior estimates: total quantity of spores released, the amount of spores exiting the room, and risk to occupants. In contrast, uncertainties were not greatly reduced for inputs for which informed prior data were available: deposition rates, resuspension rates, and sample recovery efficiencies. This suggests that prior estimates of these quantities that were obtained from a review of the technical literature are consistent with the observed behavior of spores in an actual attack. Posterior estimates of mortality risk for people in the room, when the spores were released, are on the order of 0.01 to 0.1, which supports the decision to administer prophylactic antibiotics. Multivariate sensitivity analyses were conducted to assess how effective different measurements were at reducing uncertainty in the estimated risk for the prior scenario. This analysis revealed that if the size distribution of the released particulates is known, then environmental sampling can be limited to accurately characterizing floor concentrations; otherwise, samples from multiple locations, as well as particulate and building air circulation parameters, need to be measured. [ABSTRACT FROM AUTHOR]

Flowback water is the solution that returns to the surface following completion of the hydraulic fracturing process during natural gas extraction. This study examines and analyzes the constituents that make up flowback waters collected from various drilling sites in Marcellus shale formation in the states of Pennsylvania, New York, and West Virginia. Flowback sampling data were collected from four different sources (the Environmental Protection Agency, Gas Technology Institute; Pennsylvania Department of Environmental Protection; Bureau of Oil and Gas Management; and the New York Department of Environmental Conservation) and compiled into one database with a total of 35,000 entries. Descriptive statistical analysis revealed high concentrations of chlorinated solvents, disinfectants, dissolved metals, organic compounds, radionuclides, and total dissolved solids. A one-way ANOVA test revealed that over 60% of the constituents tested displayed significant differences (significance level=0.05) in mean concentrations among the four data sources. Relative prioritization scores were developed for 58 constituents by dividing observed mean concentrations by the maximum contamination level (MCL) guidelines for drinking water. The following constituents were found to have mean concentrations over 10 times greater than the MCL: 1,2-dichloroethane, antimony, barium, benzene, benzo(a)pyrene, chloride, dibromochloromethane, gross alpha, iron, manganese, pentachlorophenol, radium, thallium, and vinyl chloride. Concentrations of anthropogenic chemicals are tightly correlated with each other, but not with chloride concentrations, and not with naturally occurring inorganics and radionuclides. [ABSTRACT FROM AUTHOR]

The Haitian government passed a law in 2009 to decentralize water utility management and improve cost recovery. This study identifies the attitudes of the public towards payment for and management of water and sanitation, several months after the 2010 earthquake, through a survey (N = 171) and semi-structured interviews (N = 19) in Leogane, Haiti. A majority of survey respondents were willing to pay for water and sanitation, which aligns with the fee-based approach of the 2009 law. Significant differences were found between geographic locations, suggesting that a neighbourhood-level approach to water and sanitation is appropriate. [ABSTRACT FROM AUTHOR]

In order to understand gaps in bioterrorism training, we surveyed 70 first responders about their training for an anthrax event. A total of 82.6% of participants had some training, but most were trained on-site by someone from their facility. Internet-based training was rarely employed and may be an under-utilized resource. Participants were fairly confident about most of their skills and training, but a plurality was not comfortable with the use of on-scene testing devices or responding to an outdoor release. Efforts to assess first responder knowledge of dispersion in both the indoor and outdoor environment suggest that first responders may underestimate the spread of anthrax. For an indoor release, 58% did not think that other parts of the building would be affected and 3% thought no environmental decontamination was needed even in the room of the release. In fact, 15% thought they could put their personal protective gear on inside the building (as actually happened in 2001) when experience has shown these areas are contaminated. In the outdoor environment downwind transport was underestimated and cross-wind transport overestimated. [ABSTRACT FROM AUTHOR]

Abstract: Low-income housing constitutes an important but often overlooked area for energy use reductions within the US residential sector. Given the scarcity of existing information on this subject, this study uses a semi-structured interview format to explore the key behavioral tendencies, energy knowledge gaps, and attitudes among low-income public housing residents, with the goal of demonstrating a process for developing, scoring, and analyzing the interviews that will be useful to other researchers when first engaging complex subjects like behavior in contexts that are not well covered by existing literature. Methods for sampling subjects and iteratively developing an interview guide and response-scoring framework are described, and the usefulness of this approach in allowing both quantitative and qualitative analysis of behavior response data is demonstrated. The paper concludes by illustrating how themes that emerge from the response analysis can be used to inform future surveying and intervention efforts. Key themes include the varying definitions for “comfort” amongst residents; the lack of resident control over the household environment; the tendency for residents to evaluate energy conservation measures (ECMs) in terms of costs, savings, and comfort; the muted differences in behavior between those who do and do not pay energy bills; and the importance of building maintenance and resident energy education to ongoing efficiency efforts. [Copyright &y& Elsevier]

Although deviations from standard guidance for land application of biosolids occur in practice, their importance is largely unknown. A list of such deviations (plausible failure scenarios) were identified at a workshop of industry, regulators, and academic professionals. Next, a survey of similar professionals was conducted to rank the plausible failure scenarios according to their severity, frequency, incentive to ignore control measures, gaps in existing control processes, public concern, and overall concern. Survey participants rated inten-tional dumping (unpermitted disposal) as the most severe of the failure scenarios, lack of worker protection as the most frequent scenario, and application of Class A biosolids that have failed to meet treatment standards as the scenario for which incentives to ignore control measures are highest. Failure of public access restrictions to application sites was the scenario for which existing controls were judged the weakest; application of biosolids too close to wells was ranked highest for public concern and for overall concern. Two scenarios for which existing controls were considered weaker, site restriction violations and animal contact leading to human exposure, were also rated as frequently occurring. Both scenarios are related in that they (1) involve inappropriate access to a site before the required time has elapsed, and (2) could be addressed through similar biosolids management measures. [ABSTRACT FROM AUTHOR]

In the aftermath of a release of microbiological agents, environmental sampling must be conducted to characterize the release sufficiently so that mathematical models can then be used to predict the subsequent dispersion and human health risks. Because both the dose-response and environmental transport of aerosolized microbiological agents are functions of the effective aerodynamic diameter of the particles, environmental assessments should consider not only the total amount of agents but also the size distributions of the aerosolized particles. However, typical surface sampling cannot readily distinguish among different size particles. This study evaluates different approaches to estimating risk from measurements of microorganisms deposited on surfaces after an aerosol release. For various combinations of sampling surfaces, size fractions, HVAC operating conditions, size distributions of release spores, uncertainties in surface measurements, and the accuracy of model predictions are tested in order to assess how much detail can realistically be identified from surface sampling results. The recommended modeling and sampling scheme is one choosing 3, 5, and 10 μm diameter particles as identification targets and taking samples from untracked floor, wall, and the HVAC filter. This scheme provides reasonably accurate, but somewhat conservative, estimates of risk across a range of different scenarios. Performance of the recommended sampling scheme is tested by using data from a large-scale field test as a case study. Sample sizes of 10-25 in each homogeneously mixed environmental compartment are sufficient to develop order of magnitude estimates of risk. Larger sample sizes have little benefit unless uncertainties in sample recoveries can be reduced. [ABSTRACT FROM AUTHOR]

This paper synthesizes available information on five Category A pathogens (Bacillus anthracis, Yersinia pestis, Francisella tularensis, Variola major and Lassa) to develop quantitative guidelines for how environmental pathogen concentrations may be related to human health risk in an indoor environment. An integrated model of environmental transport and human health exposure to biological pathogens is constructed which 1) includes the effects of environmental attenuation, 2) considers fomite contact exposure as well as inhalational exposure, and 3) includes an uncertainty analysis to identify key input uncertainties, which may inform future research directions. The findings provide a framework for developing the many different environmental standards that are needed for making risk-informed response decisions, such as when prophylactic antibiotics should be distributed, and whether or not a contaminated area should be cleaned up. The approach is based on the assumption of uniform mixing in environmental compartments and is thus applicable to areas sufficiently removed in time and space from the initial release that mixing has produced relatively uniform concentrations. Results indicate that when pathogens are released into the air, risk from inhalation is the main component of the overall risk, while risk from ingestion (dermal contact for B. anthracis) is the main component of the overall risk when pathogens are present on surfaces. Concentrations sampled from untracked floor, walls and the filter of heating ventilation and air conditioning (HVAC) system are proposed as indicators of previous exposure risk, while samples taken from touched surfaces are proposed as indicators of future risk if the building is reoccupied. A Monte Carlo uncertainty analysis is conducted and input-output correlations used to identify important parameter uncertainties. An approach is proposed for integrating these quantitative assessments of parameter uncertainty with broader, qualitative considerations to identify future research priorities. [ABSTRACT FROM AUTHOR]

In the wake of the 2001 terrorist attacks, the use of Bacillus anthracis (anthrax) in bioterrorism attacks has emerged as a realistic concern. Thus, a contingency plan is needed to inform decision-makers about which response actions are appropriate and justified under which circumstances. This study considers the decisions: (1) to undertake prophylactic antibiotic treatment; (2) to vaccinate individuals; or (3) to decontaminate the building. While these response actions are clearly justified for highly exposed individuals, a very large number of individuals exposed to very small risks in areas outside of the immediate vicinity of the release are also likely. Our results indicate that there are non-negligible risk thresholds below which response actions produce more costs than benefits. For the base case, the thresholds range from a risk of 1 in 33 for decontamination by fumigation to 1 in 6,547 for antibiotic prophylaxis and 1 in 7,108 for vaccination. A one-way sensitivity analysis on uncertain variables indicates less than an order of magnitude change in these thresholds. Benefit-cost analysis is a useful tool for assessing tradeoffs among alternative decisions, but cannot be the sole criterion in responding to incidents because of inherent limitations. [ABSTRACT FROM AUTHOR]

Objectives. Low-income residents of northern Mexico rely on unvented heaters during the winter, a practice that puts them at elevated risk for carbon monoxide intoxication. The goal of this study is to develop a communication protocol for carbon monoxide intoxication risks among the primarily low socioeconomic status population of Ciudad Juárez, Chihuahua, Mexico. Methods. The mental models risk communication approach was used to identify important gaps in public understanding. This approach consists of step-by-step assessment of information needs and effectiveness of risk communication efforts by using interviews and surveys. Results. The mental models process uncovered a key technical misunderstanding, the subject population's belief that carbon monoxide can be seen or smelled, which may result in a risk-prone behavior: failure to use a carbon monoxide detector. A communication protocol was designed to address this and other knowledge gaps, and it produced significant improvements in subjects' knowledge in a pretest/posttest evaluation. Conclusions. The mental models process was successful in developing a communication instrument capable of improving knowledge in the subject population. Future research needs include assessing the extent to which this instrument succeeds in changing behavior and reducing the risk of carbon monoxide intoxication. Future interventional efforts may focus on encouraging people to use carbon monoxide detectors. [ABSTRACT FROM AUTHOR]

Abstract: This study assessed exposure to carbon monoxide from gas and wood heater emissions in a sample of 64 households in peri-urban residential areas in Ciudad Juárez, Chihuahua, México. Indoor and outdoor carbon monoxide concentrations and temperatures were monitored for a continuous period of 1 week at 1 and 6-min intervals, respectively. The moving average carbon monoxide concentrations were compared to the World Health Organization (WHO) standards for carbon monoxide. Sixty-seven percent of households with gas heaters and 60% of households with wood heaters exceeded a health-based standard at some point during the monitoring. The difference between indoor and outdoor temperatures was modestly correlated with average carbon monoxide exposure (r=0.35, p-value <0.01). Heater type may be a stronger determinant of exposure, as households with a particular heater model (the El Sol FM-210) were significantly more likely to be among the more highly exposed households (odds ratio of 4.8, p-value of 0.02). A variety of health effects were pooled and found at elevated frequency in the households that exceeded the 8-h standard of 9ppm (odds ratio=5.1, p-value=0.031). These results highlight the need for further efforts to identify and mitigate potentially hazardous carbon monoxide exposures, particularly in moderate-income countries with cooler climates. [Copyright &y& Elsevier]

Examines the revision of arsenic drinking water standard in the United States. Consideration of cost in promulgating maximum contaminant level for water; Discrepancy in the cost estimates for arsenic treatment; Importance of regulatory guidance by the state.

• An uncertainty propagation method was developed which captures climate uncertainties. • The method is applicable to cases where few future weather files can be developed. • The method can reduce computation requirements following a probabilistic approach. • The impact of equipment modernization using updated design day files is investigated. In the United States, buildings consume a significant portion of total energy use and contribute to carbon emissions. Therefore, evaluating their performance for sustainable design is critical. While building standards are updated frequently to improve building efficiency, the climate is changing and classical (deterministic) approaches to quantifying building energy use may not be accurate. Significant uncertainties exist in current models of future building performance. Probabilistic approaches to evaluate whole building performance and account for climate uncertainties require large input data of climate projections with detailed spatial and temporal resolution and considerable computational resources. This paper offers a four-step process to propagate climate uncertainties from future climate projections into building energy performance. The climate uncertainty propagation method consists of a combination of regression, distribution fitting and random sampling. It has the potential to capture climate uncertainties in building simulation tools and is applicable to cases where limited future weather files can be produced. In addition, we include the use of updated design day files in future building performance analysis. Design days drive equipment modernization impacting whole building energy use under climate change. The Department of Energy office reference buildings for Philadelphia climate conditions are used as the case study. The aim of this research is to generate a probabilistic model that captures future building energy performance trends where can be applicable to regions that have limited future hourly weather files to be incorporated into building simulation tools. The results of this paper are intended to promote a probabilistic approach to account for climate uncertainties and to provide guidance in analyzing buildings projected energy consumption under climate change. [ABSTRACT FROM AUTHOR]

• Urban soil moisture is influenced by presence of adjacent impervious surfaces. • Urban soil moisture patterns are related to precipitation, season, and hydraulic loading. • Surface soils experience more frequent, larger swings in moisture than deeper soils. Soil-water-climate-vegetation interactions jointly determine the ability of landscapes to provide ecosystem functions and services. In particular, spatio-temporal patterns in soil moisture underpin landscape ecohydrology. Though these patterns have been of interest to researchers for some time, there is new interest in the topic today as city managers engineer green infrastructure (GI) into urban landscapes. This paper presents soil moisture data collected from 2012 to 2014, and weighing lysimeter observations continuing through 2016, in two urban GI systems. Relationships between precipitation history, season, soil depth, hydraulic loading ratio (HLR) on the frequency and magnitude of soil moisture responses are described quantitatively. A logistic regression model is used to quantify the odds that each of these variables triggers a detectable soil moisture response. The results suggest that the higher HLR site (Site 2, HLR = 3.8) had 129.7% higher odds of a soil moisture response than Site 1 (HLR = 1). The results also indicate that there are 82.9% lower odds of a response in summer than in winter. Moreover, the odds of a response decrease with increasing soil depth. The linkage between GI siting and design decisions that impact soil moisture and ecosystem services is illustrated by also reporting evapotranspiration (ET) rates at the sites as determined by the lysimeter. Higher ET observed during wetter conditions supports the hypothesis that GI siting and design factors that lead to higher moisture content can engender greater ecosystem services associated with this hydrologic process. Indeed, the higher HLR of Site 2 sustained higher soil moisture levels during the summer compared to Site 1. [ABSTRACT FROM AUTHOR]

The selection of locations and practices for energy crops requires the economics to be planned and the carbon intensity of the fuel to be assessed. This study develops a framework for selecting near‐optimal cropland sites to minimize the cost to produce a targeted quantity of an energy crop, considering soil properties, fertilizer management, and spatio‐temporal trends in crop yield and soil emissions. DayCent, a biogeochemical model, simulates site‐level crop yield, and soil emissions. As a case study, this framework is applied to a 2.08 × 108 L year−1 capacity barley‐to‐ethanol biorefinery that selects cultivation sites from winter fallow cropland in the mid‐Atlantic region of the USA. The framework implements carbon crediting as per California's Low Carbon Fuel Standard. Our analysis finds the biorefinery's strategy on co‐products significantly influences its life‐cycle carbon intensity ranging between 0.74 gCO2e MJ−1 for all co‐product use and 59 gCO2e MJ−1 for no co‐product use. Coastal counties in Delaware show low soil emission and high yield, but higher transportation distances increase the carbon intensity of these distant croplands. When co‐products are used, the least intensive fertilizer management with fertilizer applications in spring is identified as the cost‐optimized choice for the biorefinery. It is also the option economically favored by growers, suggesting that detailed monitoring of these practices might not be needed to assure the adoption of low‐emission cultivation practices. However, the framework might demonstrate different results for other biofuel‐crop scenarios or different locations. The framework presented can assess the performance of a biorefinery prospectively and improve investors' confidence in the biofuel industry. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The study estimated the risk due to Cryptosporidium, Giardia, and Ascaris, associated with non-potable water reuse in the city of Jaipur, India. The study first determined the exposure dose of Cryptosporidium, Giardia, and Ascaris based on various wastewater treatment technologies for various scenarios of reuse for six wastewater treatment plants (WWTPs) in the city. The exposure scenarios considered were (1) garden irrigation; (2) working and lounging in the garden; and (3) consumption of crops irrigated with recycled water. The estimated annual risk of infection varied between 8.57 × 10-7 and 1.0 for protozoa and helminths, respectively. The order of treatment processes, in decreasing order of annual risk of infection, was found to be: moving-bed bioreactor (MBBR) technology.activated sludge process (ASP) technology. sequencing batch reactor (SBR) technology. The estimated annual risk was found to be in this order: Ascaris. Giardia.Cryptosporidium. The study also estimated the maximum allowable concentration (Cmax) of pathogen in the effluent for a benchmark value of annual infection of risk equal to 1:10,000, the acceptable level of risk used for drinking water. The estimated Cmax values were found to be 6.54 × 10-5, 1.37 × 10-5, and 2.89 × 10-6 (oo) cysts/mL for Cryptosporidium, Giardia, and Ascaris, respectively. [ABSTRACT FROM AUTHOR]

A response from the authors of the article "Characterization of Marcellus Shale Flowback Water" in the 2014;31(9) issue is presented.

A letter to the editor is presented regarding a study, which examines 91 incidents of carbon monoxide intoxication from October 2003 to February 2004 in Mexico published in the September 1, 2005 issue.

We used the Delphi method to identify areas of consensus and disagreement in managing building water systems. One hundred and six experts were invited, 25 of whom completed both rounds. More than 95% of experts agreed that current plumbing codes are not adequate and return loop temperature should be monitored. A notably low percentage of experts agreed on the required level of chloramine (i.e., 32%) and flushing frequency (22%), despite these being common control strategies. Consensus was not achieved for temperature and disinfectant residuals, but a plurality of respondents indicated that a temperature of 55(C was appropriate and that low but detectable levels of disinfectant residuals are appropriate. After Round 2, a majority of the experts agreed that the knowledge syntheses provided were helpful and unbiased. Findings from this study will help stakeholders by providing helpful insights on plumbing code, design factors, operational factors, and water quality monitoring practices. [ABSTRACT FROM AUTHOR]

Biomass resources could be used in the Northeastern U.S. in centralized district heating networks supplied by combined heat and power (CHP) plants to reduce consumption of petroleum resources (fuel oil), generate renewable electricity, and cost-effectively reduce greenhouse gas (GHG) emissions when supplying buildings with space and water heating. Alternatively, the CHP plants could be powered by natural gas, which would reduce GHG emissions relative to conventional, individual heating solutions owing to the improved efficiency of cogeneration. To assess the potential for investment in these technologies, hourly heat load demand in residential and commercial buildings in all New England and New York state towns (populations > 5000) was estimated and used to optimize the energy efficiency of district heating networks using MODEST software. All of the 116 studied locations without access to natural gas distribution infrastructure showed negative carbon abatement costs, the majority between −$250 and −$38 per Mg CO 2 equivalents (eq.), when biomass-fed district heating was implemented due to significantly reduced operational costs and life cycle GHG emissions. Similarly, almost all (465 out of 467) locations connected to the natural gas grid were found to have negative GHG abatement costs, ranging from −$4500 to −$400 per Mg CO 2 eq., demonstrating strong economic feasibility for district heating. Natural has an economic advantage over biomass in district heating due to its combined cycle CHP plants being able to generate more electricity per heat unit compared to biomass CHP plants and its lower O&M costs. District heating in all locations could abate 2.6 billion Mg of CO 2 eq. at an economic surplus over 30 ears of continuous operation. Using a framework that integrated spatial tools, optimization, LCA, and cost evaluation, this study uniquely identified promising locations in the U.S. where district heating could be both environmentally and economically beneficial. This framework can be applied to other global regions that have significant space heating needs, for CHP implementation, and as a tool for identifying alternative building energy investments, such as improved insulation or individual space heating solutions, which in some cases could yield higher GHG reductions per dollar. [ABSTRACT FROM AUTHOR]

This paper introduces a Human and Building Interaction Toolkit (HABIT) for simulating the thermally adaptive behaviors and comfort of office occupants alongside building energy consumption. The toolkit uses the Building Controls Virtual Test Bed (BCVTB) to co-simulate a field-tested, agent-based behavior model with an EnergyPlus medium office model. The usefulness of the toolkit is demonstrated through a series of zone and building-level case study simulations that examine the wisdom of pairing local heating and cooling options with strategic thermostat set point offsets, judging from the energy, Indoor Environmental Quality (IEQ), and cost perspectives. Results generally suggest that trading efficient local heating/cooling options for whole space conditioning has both energy and comfort benefits, saving up to 28% of monthly HVAC energy while improving the acceptability of thermal conditions in a Philadelphia climate. Nevertheless, cost analysis shows that the fuel source of conserved energy must be considered – particularly in the case of personal heater use, which adds to electric plug loads and associated utility and CO 2 emissions cost penalties. Moreover, costs from even small changes in simulated occupant productivity tend to overwhelm energy costs, suggesting the need to improve the accuracy and precision of available productivity models across multiple seasons and climates. [ABSTRACT FROM AUTHOR]

This study examines the influence of chlorine disinfectant type, water use frequency (stagnation time), and water heater temperature on the growth and persistence of microbes, including nontuberculous mycobacteria (NTM), in water heater storage tanks and downstream plumbing. The experimental setup consists of four 50-gallon electric water heater tanks at two different locations that provide different types of secondary disinfectant (chloramine and free chlorine). The water heaters were operated at two different temperature settings (45°C ± 3°C and 60°C ± 3°C), and with two different use patterns (once per 24 h and three times per 24 h), which allowed for sampling at three different stagnation times: overnight, 16-h stagnation, and 3-h stagnation. Microbial analyses were conducted on water samples collected at the tank effluent and the shower head to compare the water quality in the tank before the stagnation period and in the piping downstream of the tank after the stagnation period. The results indicated that culturable NTM was not detected under any of the conditions studied in the free chlorine disinfectant system. In the chloramine system, higher water use frequency (equivalent to 180 gallons/day) and higher water heater temperature (60°C ± 3°C) decreased the number of heterotrophic bacteria in the tank and the piping downstream to the tank but failed to control NTM. For both heterotrophic plate count and NTM, the piping downstream was not more microbially active than the tank. [ABSTRACT FROM AUTHOR]

Although approximately 35 million people in the US obtain drinking water from domestic wells, few studies have investigated the risk of arsenic exposure from this source. In this paper arsenic concentrations were modeled for public and domestic wells using a dataset from the US Geological Survey (USGS). Excess lifetime and annual risks for lung and bladder cancer were calculated based on the carcinogenic potency and average arsenic concentrations in public and domestic water supplies. Monte Carlo uncertainty analysis was used to estimate the degree of confidence in these estimations. Results indicated that domestic well users accounted for 12% of the US population, but 23% of overall arsenic exposure from drinking water. Assuming that the new and more restrictive arsenic maximum contaminant limit (MCL) is implemented for public water supplies, it is anticipated that the proportion of people experiencing excess annual fatalities from drinking water from domestic wells will increase to 29% unless corresponding efforts are made to reduce exposures among domestic well users. Differences between public and domestic wells were not consistent across the nation. Public wells tend to tap deeper aquifers than domestic wells, and as a result local arsenic-depth trends can contribute to differences between public and domestic wells. Domestic wells and public wells in the western US have the highest arsenic levels with excess fatality risks estimated to be in the range of 1 per 9300 to 1 per 6600 in these regions. Uncertainty distributions of excess fatalities were developed and resultant uncertainties were propagated in arsenic exposure and potency factor. Uncertainty in the carcinogenic potency of arsenic was the dominant source of uncertainty in most regions, but for domestic wells in the New England and Southeast regions uncertainty in arsenic exposure was dominant, indicating that additional data on arsenic concentrations in these areas would substantially improve regional risk estimates. [ABSTRACT FROM AUTHOR]

The current framework for U.S. Environmental Protection Agency regulation of water quality in community drinking water supplies produces sequential rules for either single contaminants or small groups of similar contaminants. For both substantive and pragmatic reasons, some water industry experts have advocated the development of a more holistic regulatory process in which rules are promulgated less frequently but for larger contaminant classes. Such a framework would require the expansion of existing regulatory evaluation technologies to account for joint occurrence distributions of multiple contaminants. This article presents an analysis, using two national contaminant databases, of the joint distributions of seven contaminants (arsenic, nitrate, uranium, manganese, magnesium, calcium, and sulfate) in community water system source waters. Inferences are based on a flexible Bayesian hierarchical modeling structure with numerous features desirable for empirical exploration of multicontaminant regulations, including the simultaneous estimation of spatial heterogeneity in contaminant levels and covariations among contaminants, applicability to sparse data collected over a large spatial scale, and coherent assimilation of information provided by censored observations. The model is used to estimate a family of joint distributions for the contaminants indexed by water system characteristics, with empirically appropriate complexity given the resolution of the available data. The resulting distributions provide insights about the nature of, and uncertainty about, contaminant co-occurrence patterns, quantify the impact on national assessments of jointly modeling the contaminants, and facilitate identification of critical classes of water systems where uncertainty is highest. [ABSTRACT FROM AUTHOR]

This study examines the effect of pipe characteristics and stagnation time on nitrification, disinfectant loss, and organic carbon concentrations. Pipe racks consisting of different pipe materials (chlorinated polyvinyl chloride [CPVC], cross‐linked polyethylene [PEX‐B], and copper), diameters (0.75 and 0.5 in.), and water stagnation times (1 week and 12 hr) were set up in two cities with different disinfectants (chloramine and free chlorine) and different corrosion control (orthophosphate vs. pH/alkalinity adjustment). Copper pipe material had lower residual concentrations relative to plastic pipe in both water systems. In the chloramine system, residual concentrations were lower for smaller‐diameter pipes, whereas diameter did not strongly influence residual concentration in the chlorine system. Total organic carbon (TOC) increased during stagnation in the chloramine system. Nitrification was observed in the chloramine system for stagnation times of 1 week and 12 hr, indicating that flushing as frequently as every 12 hr may not be an effective mechanism for nitrification control in building plumbing. [ABSTRACT FROM AUTHOR]

Focuses on the correlation between diabetes prevalence and air pollution emissions in the U.S. Use of multivariate regression approach in the study; Analysis of the state level emissions data; Utilization of the data to improve health outcomes.

This paper investigates strategies that could achieve an 80% reduction in transportation emissions from current levels by 2050 in the City of Philadelphia. The baseline daily lifecycle emissions generated by road transportation in the Greater Philadelphia Region in 2012 were quantified using trip information from the 2012 Household Travel Survey (HTS). Emissions were projected to the year 2050 accounting for population growth and trends in vehicle technology for both the Greater Philadelphia Region and the City of Philadelphia. The impacts of vehicle technology and shifts in travel modes on greenhouse gas (GHG) emissions in 2050 were quantified using a scenario approach. The analysis of 12 different scenarios suggests that 80% reduction in emissions is technically feasible through a combination of active transportation, cleaner fuels for public transit vehicles, and a significant market penetration of battery-electric vehicles. The additional electricity demand associated with greater use of electric vehicles could amount to 10.8 TWh/year. The use of plug-in hybrid electric vehicles (PHEV) shows promising results due to high reductions in GHG emissions at a potentially manageable cost. [ABSTRACT FROM AUTHOR]

Summary: Bacillus spores resist inactivation, but the extent of their persistence on common surfaces is unclear. This work addresses knowledge gaps regarding biothreat agents in the environment to reduce uncertainty in risk assessment models. Studies were conducted to investigate the long‐term inactivation of Bacillus anthracis and three commonly used surrogate organisms – B. cereus, B. atrophaeus and B. thuringiensis on three materials: laminate countertop, stainless steel and polystyrene Petri dishes. Viable spores were measured at 1, 30, 90, 196, 304 and 1038 days. Twelve different persistence models were fit to the data using maximum likelihood estimation and compared. The study found that (1) spore inactivation was not log‐linear, as commonly modelled; (2) B. thuringiensis counts increased at 24 h on all materials, followed by a subsequent decline; (3) several experiments showed evidence of a 'U' shape, with spore counts apparently decreasing and then increasing between 1 and 304 days; (4) spores on polystyrene showed little inactivation; and (5) the maximum inactivation of 56% was observed for B. atrophaeus spores on steel at 196 days. Over the range of surfaces, time durations and conditions (humidity controlled vs. uncontrolled) examined, B. thuringiensis most closely matched the behaviour of B. anthracis. This work is the first of its kind to jointly present an experimental and modelling study that characterizes the long‐term persistence of Bacillus spores on common surfaces by natural decay over a 3 year period. The implications of model selection and extrapolation beyond the final time point are elucidated for microorganisms that persist for long periods of time on environmental media. The study also informs the selection of suitable surrogates based on their behaviour under similar conditions over time. [ABSTRACT FROM AUTHOR]

Participatory engineering has been called for after major catastrophes, yet is often bypassed due to countervailing implementation of ‘quick fixes’. While immediate expert-driven solutions may be attractive, in the long-term they may be ineffective and inconsistent with the goals and capacities of local stakeholders. This article discusses the findings of National Science Foundation research by a team of three engineers and one social scientist who visited Haiti twice, four and seven months after the January 2010 earthquake, to investigate community participation in water and sanitation engineering processes in Léogâne. Methods included interviews with local inhabitants, water-sector actors, and government agencies; inspections of the engineering of the existing water and sanitation system; surveys of the affected population; and a participatory workshop to which numerous community-based organizations were invited. The research tests the potential for engineers to develop stakeholder-based participatory processes in a post-disaster context, which is hypothesized to produce better outcomes than traditional top-down authoritative planning processes. Focusing on the sanitation sector within a multi-stakeholder arena, the article analyzes the potential for various kinds of interactions amongst actors during unfolding decision-making processes at multiple scales, and assesses how each might contribute to better post-disaster engineering and ultimately more sustainable water and sanitation systems. [ABSTRACT FROM PUBLISHER]

The article presents a study which assesses the risk of heterotrophic plate count (HPC) bacteria in potable water sources in Mexico. The study used 88 water samples collected from four drinking water sources including the oratorio water, the store bought water, indoor, and outdoor faucet water. It was found out that there was no statistically significant differences among the four water sources.

Observations of traffic inspections at a U.S. land border port of entry in El Paso, TX indicate that the process is highly variable. In a series of 24 half-hour observation periods of ordinary noncommercial traffic, the average inspection duration ranged from 16.6 s to 56.6 s. The proportion of inspections which involved some physical search of the vehicle, as indicated by the inspector leaving the inspection booth, varied from 5% to 56% in different observation periods. In 4 out of 10 cases, the log-mean of inspection duration in simultaneous observations of parallel lanes of traffic differed significantly (p<0.05). This suggests that differences in inspector behavior are responsible for much of the variability of the inspection process. Similar results are found for the SENTRI program. A survey of public perception reveals that a majority of English-language respondents perceive the inspectors to be fair while a majority of Spanish language respondents (both U.S. and Mexican citizens) perceive the process to be more arbitrary, as they state that fairness "depends on the inspector." Spanish-language respondents are also more likely to report having to submit to additional searches than English-language respondents. A common theme that emerges from the analysis of these two datasets is that efforts to standardize some aspects of inspections, while preserving inspector autonomy, may improve the performance of the process by eliminating variability which organized criminal groups may be able to exploit. [ABSTRACT FROM AUTHOR]

Legionella spp. occurring in hotel hot water systems, in particular Legionella pneumophila, are causing serious pneumonic infections, and water temperature is a key factor to control their occurrence in plumbing systems. We performed a systematic review and meta-analyses of the available evidence on the association between water temperature and Legionella colonization to identify the water temperature in hotel hot water systems required for control of Legionella. Qualitative synthesis and quantitative analysis were performed on 13 studies that met our inclusion criteria to identify the effect of temperature. The Receiver Operating Characteristic (ROC) curve identified 55 °C as a cutoff point for hotel hot water temperature with an Area Under the Curve (AUC) value of 0.914. The odds ratios (OR) for detecting Legionella at temperatures >55 °C compared to lower temperatures from a meta-analysis of three studies was 0.17 [95% CI: 0.11, 0.25], which indicates a strong negative association between temperature and Legionella colonization. A logistic regression on results from multiple studies using both molecular and culture methods found a temperature of 59 °C associated with an 8% probability of detectable Legionella. Only two studies reported sufficiently detailed data to allow a model of concentration vs. temperature to be fit, and this model was not statistically significant. Additional research or more detailed reporting of existing datasets is required to assess if Legionella growth can be limited below particular concentration targets at different temperatures. Image 1 • A systematic review of the association between temperature and Legionella in hotels. • The effects of temperature to control Legionella were identified. • 55 °C to 59 °C was identified as likely to reduce Legionella to non-detectable levels. • Species of Legionella has a minimal impact, but analytical method affects results. • Identified temperature can be used to calculate the water heater temperature. [ABSTRACT FROM AUTHOR]

Renewable fuel standards for biofuels have been written into policy in the U.S. to reduce the greenhouse gas (GHG) intensity of transportation energy supply. Biofuel feedstocks sourced from within a regional market have the potential to also address sustainability goals. The U.S. Mid-Atlantic region could meet the advanced fuel designation specified in the Renewable Fuel Standard (RFS2), which requires a 50% reduction in GHG emissions relative to a gasoline baseline fuel, through ethanol produced from winter barley (Hordeum vulgare L.). We estimate technology configurations and winter barley grown on available winter fallow agricultural land in six Mid-Atlantic states. Using spatially weighted stochastic GHG emission estimates for winter barley supply from 374 counties and biorefinery data from a commercial dry-grind facility design with multiple co-products, we conclude that winter barley would meet RFS2 goals even with the U.S. EPA's indirect land use change estimates. Using a conservative threshold for soil GHG emissions sourced from barley produced on winter fallow lands in the U.S. MidAtlantic, a biorefinery located near densely populated metropolitan areas in the Eastern U.S. seaboard could economically meet the requirements of an advanced biofuel with the co-production of CO2 for the soft drink industry. [ABSTRACT FROM AUTHOR]