Emissions of organic compounds from produced water ponds II: Evaluation of flux chamber measurements with inverse-modeling techniques

In this study, the authors apply two different dispersion models to evaluate flux chamber measurements of emissions of 58 organic compounds, including C2–C11 hydrocarbons and methanol, ethanol, and isopropanol from oil- and gas-produced water ponds in the Uintah Basin. Field measurement campaigns using the flux chamber technique were performed at a limited number of produced water ponds in the basin throughout 2013–2016. Inverse-modeling results showed significantly higher emissions than were measured by the flux chamber. Discrepancies between the two methods vary across hydrocarbon compounds and are largest in alcohols due to their physical chemistries. This finding, in combination with findings in a related study using the WATER9 wastewater emission model, suggests that the flux chamber technique may underestimate organic compound emissions, especially alcohols, due to its limited coverage of the pond area and alteration of environmental conditions, especially wind speed. Comparisons of inverse-model estimations with flux chamber measurements varied significantly with the complexity of pond facilities and geometries. Both model results and flux chamber measurements suggest significant contributions from produced water ponds to total organic compound emission from oil and gas productions in the basin.

Implications: This research is a component of an extensive study that showed significant amount of hydrocarbon emissions from produced water ponds in the Uintah Basin, Utah. Such findings have important meanings to air quality management agencies in developing control strategies for air pollution in oil and gas fields, especially for the Uintah Basin in which ozone pollutions frequently occurred in winter seasons.     

Factors contributing to serious and fatal injuries in belted rear seat occupants in frontal crashes

Abstract

Objectives: Earlier research has shown that the rear row is safer for occupants in crashes than the front row, but there is evidence that improvements in front seat occupant protection in more recent vehicle model years have reduced the safety advantage of the rear seat versus the front seat. The study objective was to identify factors that contribute to serious and fatal injuries in belted rear seat occupants in frontal crashes in newer model year vehicles.

Methods: A case series review of belted rear seat occupants who were seriously injured or killed in frontal crashes was conducted. Occupants in frontal crashes were eligible for inclusion if they were 6 years old or older and belted in the rear of a 2000 or newer model year passenger vehicle within 10 model years of the crash year. Crashes were identified using the 2004–2015 National Automotive Sampling System Crashworthiness Data System (NASS-CDS) and included all eligible occupants with at least one Abbreviated Injury Scale (AIS) 3 or greater injury. Using these same inclusion criteria but split into younger (6 to 12 years) and older (55+ years) cohorts, fatal crashes were identified in the 2014–2015 Fatality Analysis Reporting System (FARS) and then local police jurisdictions were contacted for complete crash records.

Results: Detailed case series review was completed for 117 rear seat occupants: 36 with Maximum Abbreviated Injury Scale (MAIS) 3+ injuries in NASS-CDS and 81 fatalities identified in FARS. More than half of the injured and killed rear occupants were more severely injured than front seat occupants in the same crash. Serious chest injury, primarily caused by seat belt loading, was present in 22 of the injured occupants and 17 of the 37 fatalities with documented injuries. Nine injured occupants and 18 fatalities sustained serious head injury, primarily from contact with the vehicle interior or severe intrusion. For fatal cases, 12 crashes were considered unsurvivable due to a complete loss of occupant space. For cases considered survivable, intrusion was not a large contributor to fatality.

Discussion: Rear seat occupants sustained serious and fatal injuries due to belt loading in crashes in which front seat occupants survived, suggesting a discrepancy in restraint performance between the front and rear rows. Restraint strategies that reduce loading to the chest should be considered, but there may be potential tradeoffs with increased head excursion, particularly in the absence of rear seat airbags. Any new restraint designs should consider the unique needs of the rear seat environment.     

Need for multiscale planning for conservation of urban bats

For over a century there have been continual efforts to incorporate nature into urban planning. These efforts (i.e., urban reconciliation) aim to manage and create habitats that support biodiversity within cities. Given that species select habitat at different spatial scales, understanding the scale at which urban species respond to their environment is critical to the success of urban reconciliation efforts. We assessed species–habitat relationships for common bat species at 50‐m, 500‐m, and 1 km spatial scales in the Chicago (U.S.A.) metropolitan area and predicted bat activity across the greater Chicago region. Habitat characteristics across all measured scales were important predictors of silver‐haired bat (Lasionycteris noctivagans) and eastern red bat (Lasiurus borealis) activity, and big brown bat (Eptesicus fuscus) activity was significantly lower at urban sites relative to rural sites. Open vegetation had a negative effect on silver‐haired bat activity at the 50‐m scale but a positive effect at the 500‐m scale, indicating potential shifts in the relative importance of some habitat characteristics at different scales. These results demonstrate that localized effects may be constrained by broader spatial patterns. Our findings highlight the importance of considering scale in urban reconciliation efforts and our landscape predictions provide information that can help prioritize urban conservation work.     

The implicit price of urban public parks and greenways: a spatial-contextual approach

This paper examines the value residents place on public parks in a mid-sized urban area. The analysis makes a direct contribution to the literature by examining the extent to which spatial and neighbourhood context is related to the house price premium or discount associated with public recreational opportunities, natural resource areas and urban greenways. The analysis shows that the value of public parks and greenways varies across space, neighbourhood context and park type. Community area fixed-effects are included to bolster the findings. The findings indicate that park and greenway investment should be planned and managed contextually in urban areas. Park planners can use these findings to inform public policy debates over park investment and, perhaps, support efforts focused on comprehensive neighbourhood planning.     

Double catastrophe: intermittent stratospheric geoengineering induced by societal collapse

Perceived failure to reduce greenhouse gas emissions has prompted interest in avoiding the harms of climate change via geoengineering, that is, the intentional manipulation of Earth system processes. Perhaps the most promising geoengineering technique is stratospheric aerosol injection (SAI), which reflects incoming solar radiation, thereby lowering surface temperatures. This paper analyzes a scenario in which SAI brings great harm on its own. The scenario is based on the issue of SAI intermittency, in which aerosol injection is halted, sending temperatures rapidly back toward where they would have been without SAI. The rapid temperature increase could be quite damaging, which in turn creates a strong incentive to avoid intermittency. In the scenario, a catastrophic societal collapse eliminates society’s ability to continue SAI, despite the incentive. The collapse could be caused by a pandemic, nuclear war, or other global catastrophe. The ensuing intermittency hits a population that is already vulnerable from the initial collapse, making for a double catastrophe. While the outcomes of the double catastrophe are difficult to predict, plausible worst-case scenarios include human extinction. The decision to implement SAI is found to depend on whether global catastrophe is more likely from double catastrophe or from climate change alone. The SAI double catastrophe scenario also strengthens arguments for greenhouse gas emissions reductions and against SAI, as well as for building communities that could be self-sufficient during global catastrophes. Finally, the paper demonstrates the value of integrative, systems-based global catastrophic risk analysis.     

Dechlorination comparison of mono-substituted PCBs with Mg/Pd in different solvent systems

It is widely recognized that polychlorinated biphenyls (PCBs) are a dangerous environmental pollutant. Even though the use and production of PCBs have been restricted, heavy industrial use has made them a wide-spread environmental issue today. Dehalogenation using zero-valent metals has been a promising avenue of research for the remediation of chlorinated compounds and other contaminants that are present in the environment. However, zero-valent metals by themselves have shown little capability of dechlorinating polychlorinated biphenyls (PCBs). Mechanically alloying the metal with a catalyst, such as palladium, creates a bimetallic system capable of dechlorinating PCBs very rapidly to biphenyl. This study primarily aims to evaluate the effects of solvent specificity on the kinetics of mono-substituted PCBs, in an attempt to determine the mechanism of degradation. Rate constants and final byproducts were determined for the contaminant systems in both water and methanol, and significant differences in the relative rates of reaction were observed between the two solvents.     

Workers' perceptions of workplace safety: an African perspective.

This study investigated workers' perceptions of workplace safety in an African work environment, specifically in Ghanaian work places. Workers' safety perceptions were examined with Hayes et al.'s. (1998) Work Safety Scale. Comparative analyses were done between high- and low-accident groups, and t tests were employed to test for differences of statistical significance. Relative to their colleagues in the low-accident category, workers in the high-accident category exhibited negative perceptions on safety. They had negative perceptions regarding work safety, safety programmes, supervisors, and co-workers' contributions. Besides, they expressed less job satisfaction and were less committed to safety management policies. Perceptions regarding management's attitude towards safety between the 2 groups were not of statistical significance. The analyses provided an explanation for the cause of a substantial portion of the high rate of industrial accidents in Ghana's work environment. Implications for safety management are discussed.     

How Preferences for Public Participation are Linked to Perceptions of the Context, Preferences for Outcomes, and Individual Characteristics

Practitioners and stakeholders involved in environmental and risk assessment and decision-making efforts have access to a growing list of policies and guidance for implementing good process. The advice is often general. There is little understanding of how situation specific features are relevant in new circumstances. In a series of ten case studies we investigated how people’s (a) perceptions of the context, (b) preferences for outcomes, and (c) affiliations, experiences and motivations are related to their preferences for process features in a particular situation. The cases are in three policy areas: watershed management, forestry management, and clean-up and public health management of radioactively contaminated sites. We conclude this paper with a discussion of how the results can inform process design. Process design should be based on a diagnostic approach that specifically assesses relevant situational characteristics.     

Effect of Introduced Crayfish and Mosquitofish on California Newts

One goal of conservation biology is to explain population declines. We present field survey data and experimental evidence that implicate introduced predators as a possible cause of decline in the California newt ( Taricha torosa ). In 1994 and 1995 we surveyed 10 streams in the Santa Monica Mountains of southern California for amphibians. These streams contained California newts when surveyed between 1981 and 1986. Of the 10 streams surveyed in 1994, three contained introduced mosquitofish ( Gambusia affinis ) and/or crayfish ( Procambarus clarkii ). These three streams contained no California newt eggs, larvae, or adults. The seven streams without introduced predators contained California newts. We conducted laboratory and field experiments to determine if California newt larvae and egg masses are susceptible to predation by mosquitofish and crayfish. Results from these experiments indicate that crayfish consume California newt egg masses and that both mosquitofish and crayfish consume larval newts. In 24-hour field experiments, no newt larvae survived in crayfish enclosures, and only 13% of the larvae survived with mosquitofish. Newt larvae are known to have antipredator adaptations for native predators. Apparently, these adaptations are not adequate for coexistence with introduced crayfish or mosquitofish. Heavy rains in 1995 removed introduced crayfish from one stream. We found newt egg masses, larvae, and adults in that stream the following spring. This same stream showed no evidence of California newts when crayfish were present in matched-date surveys in 1994. These experiments and surveys present evidence that predation by mosquitofish and crayfish may cause localized decline of newts in mountain streams of southern California. Understanding the effects of nonnative species is an important step in preventing detrimental introductions in the future.