Characteristics in oxidative degradation by ozone for saturated hydrocarbons in soil contaminated with diesel fuel

Although alkanes are relatively less reactive to chemical oxidation compared to alkenes, the chemical oxidation of alkanes has not been adequately explored in the context of environmental remediation efforts. Laboratory-scale column experiments were therefore conducted with soil artificially contaminated by diesel fuel as a surrogate for alkanes of environmental relevance. Particular attention was paid to saturated hydrocarbons refractory to volatilization. Reaction conditions involve 1485mgkg(-1) of the initial concentration of diesel range organics (DRO) and a constant ozone concentration of 119+/-6mgl(-1) at the flow rate of 50mlmin(-1). The observed removal of DRO reached 94% over 14h of continuous ozone injection. Ozone oxidation demonstrated effective removal of non-volatile DRO in the range of C(12)-C(24). Each alkane compound displayed comparable degradation kinetics, suggesting virtually no selectivity of ozone reactions with alkanes in soil. A pseudo-first order kinetic model closely simulated the removal kinetics, yielding a reaction rate constant of 0.213 (+/-0.021)h(-1) and a half-life of 3.3 (+/-0.3)h under the experimental conditions used in this study. An estimate of ozone demand was 32mg of O(3) (mgDRO)(-1).     

When are historical data sufficient for making watershed-level stream fish management and conservation decisions?

Addressing landscape-level threats to stream fishes such as habitat and hydrological alterations requires adequate watershed-level species inventories. Where watershed-level ichthyofaunal surveys are prohibitively expensive, existing (historical) data sources may provide an option for compiling species lists. However, it is critical that managers consider potential biases or limitations of species lists compiled from existing data. Here we assess the suitability of species lists compiled from existing data sources for making watershed-level fish management and conservation decisions. For nine Great Lakes watersheds, we developed existing species lists by compiling all available federal and state agency and museum fish survey data. We then compared the size and species composition of existing species lists to current species lists compiled from intensive field surveys, conducted in 2002, of the same watersheds. Species lists compiled from commonly available existing data sources, such as state and federal agency and museum data, missed many species detected during our 2002 field surveys. In most watersheds, more than 10 species were missed (range 5–21) on existing lists. Sampling over multiple years and seasons increased the size of both current (field) and existing species lists. Existing species lists compiled from surveys conducted over multiple years and seasons included an average of 15 species not captured during the 2002 field surveys. However, such multiyear existing datasets are rare and not available for many watersheds. In addition, species lists compiled from older existing surveys (e.g., before 1984) did not accurately represent current species composition of the watersheds and our results indicate several apparent misidentifications or errors on these lists. Lastly, while most game species were detected on existing lists, migratory species and recently introduced species were commonly missed on these lists. We conclude with recommendations for using existing data for watershed-level stream fish management and conservation decisions.     

Soil nitrous oxide emissions following band-incorporation of fertilizer nitrogen and swine manure

Treatment of liquid swine manure (LSM) offers opportunities to improve manure nutrient management. However, N2O fluxes and cumulative emissions resulting from application of treated LSM are not well documented. Nitrous oxide emissions were monitored following band-incorporation of 100 kg N ha(-1) of either mineral fertilizer, raw LSM, or four pretreated LSMs (anaerobic digestion; anaerobic digestion + flocculation: filtration; decantation) at the four-leaf stage of corn (Zea mays L.). In a clay soil, a larger proportion of applied N was lost as N2O with the mineral fertilizer (average of 6.6%) than with LSMs (3.1-5.0%), whereas in a loam soil, the proportion of applied N lost as N2O was lower with the mineral fertilizer (average of 0.4%) than with LSMs (1.2-2.4%). Emissions were related to soil NO3 intensity in the clay soil, whereas they were related to water-extractable organic C in the loam soil. This suggests that N2O production was N limited in the clay soil and C limited in the loam soil, and would explain the interaction found between N sources and soil type. The large N2O emission coefficients measured in many treatments, and the contradicting responses among N sources depending on soil type, indicate that (i) the Intergovernmental Panel on Climate Change (IPCC) default value (1%) may seriously underestimate N2O emissions from fine-textured soils where fertilizer N and manure are band-incorporated, and (ii) site-specific factors, such as drainage conditions and soil properties (e.g., texture, organic matter content), have a differential influence on emissions depending on N source.     

Lability of polycyclic aromatic hydrocarbons in the rhizosphere

Remediation of soils containing high concentrations of polycyclic aromatic hydrocarbons (PAHs) seldom results in complete removal of contaminants, but residual toxicity often is reduced. In this study, soil from a former manufactured gas plant site was treated for 12 months by phytoremediation and then tested for total PAHs, Tenax-TA extractable ("labile") PAHs, aqueous soluble PAHs (PAH(wp)) , and biotoxicity assessed by earthworms survival, nematode mortality, emergence of lettuce seedlings, and microbial respiration. Prior to phytoremediation, the soil had toxic impacts on all bioassays (except the nematodes), and 12 months of remediation decreased this response. Change in labile PAHs was a predictor for change in total PAH for 3- and 4-ring compounds but not for the 5- and 6-ring. Decreases in labile PAHs were correlated (r(2)>or=0.80) with toxicity in the bioassays except microbial respiration. PAH(wp) was correlated only with nematode toxicity prior to remediation but with none of the tests after remediation. Total PAHs were not correlated with any of the bioassay tests. Tenax-TA appears to have potential for predicting residual toxicity in remediated soils and is superior to total concentrations for that application.     

Influence of a soil enzyme on iron-cyanide complex speciation and mineral adsorption

Cyanide is commonly found as ferrocyanide [Fe(II)(CN)(6)](-4) and in the more mobile form, ferricyanide [Fe(III)(CN)(6)](-3) in contaminated soils and sediments. Although soil minerals may influence ferrocyanide speciation, and thus mobility, the possible influence of soil enzymes has not been examined. In a series of experiments conducted under a range of soil-like conditions, laccase, a phenoloxidase enzyme derived from the fungi Trametes versicolor, was found to exert a large influence on iron-cyanide speciation and mobility. In the presence of laccase, up to 93% of ferrocyanide (36-362ppm) was oxidized to ferricyanide within 4h. No significant effect of pH (3.6 and 6.2) or initial ferrocyanide concentration on the extent or rate of oxidation was found and ferrocyanide oxidation did not occur in the absence of laccase. Relative to iron-cyanide-mineral systems without laccase, ferrocyanide adsorption to aluminum hydroxide and montmorillonite decreased in the presence of laccase and was similar to or somewhat greater than that of ferricyanide without laccase. Laccase-catalyzed conversion of ferrocyanide to ferricyanide was extensive though up to 33% of the enzyme was mineral-bound. These results demonstrate that soil enzymes can play a major role in ferrocyanide speciation and mobility. Biotic soil components must be considered as highly effective oxidation catalysts that may alter the mobility of metals and metal complexes in soil. Immobilized enzymes should also be considered for use in soil metal remediation efforts.     

Deconstructing compassionate conservation

Compassionate conservation focuses on 4 tenets: first, do no harm; individuals matter; inclusivity of individual animals; and peaceful coexistence between humans and animals. Recently, compassionate conservation has been promoted as an alternative to conventional conservation philosophy. We believe examples presented by compassionate conservationists are deliberately or arbitrarily chosen to focus on mammals; inherently not compassionate; and offer ineffective conservation solutions. Compassionate conservation arbitrarily focuses on charismatic species, notably large predators and megaherbivores. The philosophy is not compassionate when it leaves invasive predators in the environment to cause harm to vastly more individuals of native species or uses the fear of harm by apex predators to terrorize mesopredators. Hindering the control of exotic species (megafauna, predators) in situ will not improve the conservation condition of the majority of biodiversity. The positions taken by so-called compassionate conservationists on particular species and on conservation actions could be extended to hinder other forms of conservation, including translocations, conservation fencing, and fertility control. Animal welfare is incredibly important to conservation, but ironically compassionate conservation does not offer the best welfare outcomes to animals and is often ineffective in achieving conservation goals. Consequently, compassionate conservation may threaten public and governmental support for conservation because of the limited understanding of conservation problems by the general public.     

Resource allocation in transboundary tuna fisheries: A global analysis

Resource allocation is a fundamental and challenging component of common pool resource governance, particularly transboundary fisheries. We highlight the growing importance of allocation in fisheries governance, comparing approaches of the five tuna Regional Fisheries Management Organizations (tRFMOs). We find all tRFMOs except one have defined resources for allocation and outlined principles to guide allocation based on equity, citizenship, and legitimacy. However, all fall short of applying these principles in assigning fish resources. Most tRFMOs rely on historical catch or effort, while equity principles rarely determine dedicated rights. Further, the current system of annual negotiations reduces certainty, trust, and transparency, counteracting many benefits asserted by rights-based management proponents. We suggest one means of gaining traction may be to shift conversations from allocative rights toward weighting of principles already identified by most tRFMOs. Incorporating principles into resource allocation remains a major opportunity, with important implications for current and future access to fish.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01371-3) contains supplementary material, which is available to authorized users.     

Why did the pilots shut down the wrong engine? Explaining errors in context using Schema Theory and the Perceptual Cycle Model

Although human error remains a dominant issue in aviation research, methods that predict human error have been criticised for not providing adequate causal explanations, rather they have focused on classification. The concept of Schemata has prevailed in the literature and has been shown to describe the contextual causes of human error. The purpose of this paper is to review the recent error literature and demonstrate that Schema Theory (as incorporated in the Perceptual Cycle framework) offers a compelling causal account of human error. Schema Theory offers a system perspective with a focus on human activity in context to explain why apparently erroneous actions occurred, even though they may have appeared to be appropriate at the time. This is exemplified in a case study of the pilots’ actions preceding the 1989 Kegworth accident. Schema Theory is presented as a promising avenue for further exploration into the context of human error in aviation.     

Challenges and needs for process safety in the new millennium

Process industries have made quite a bit of progress in process safety since the tragic night of December 2, 1984 in Bhopal. Nonetheless, incidents continue to occur on a regular basis due to insufficient understanding of the urgency to identify best practices and drive for process safety improvements in the organization. This paper addresses some of the critical challenges in implementing effective safety programs: (a) failure to learn from past incidents and to capture those lessons into process design, procedures, training, maintenance, and other programs, (b) insufficient attention to leading indicators, and (c) an increase in complexity of process operations and lack of communication. In the presence of these challenges, there is a great need to develop better solutions by utilizing good science based approaches and best practice studies. Potential research areas include, but are not limited to, incident database analysis, reactive chemicals, inherently safer design, combustible dust explosion, facility siting, and the flammability of fuel mixtures and aerosols. In addition, an example was presented on LNG industry safety to illustrate that science-based research is needed to ensure the safe operation and to avoid or mitigate unintended consequences.     

Environmental Awareness and Public Support for Protecting and Restoring Puget Sound

In an effort to garner consensus around environmental programs, practitioners have attempted to increase awareness about environmental threats and demonstrate the need for action. Nonetheless, how beliefs about the scope and severity of different types of environmental concerns shape support for management interventions are less clear. Using data from a telephone survey of residents of the Puget Sound region of Washington, we investigate how perceptions of the severity of different coastal environmental problems, along with other social factors, affect attitudes about policy options. We find that self-assessed environmental understanding and views about the seriousness of pollution, habitat loss, and salmon declines are only weakly related. Among survey respondents, women, young people, and those who believe pollution threatens Puget Sound are more likely to support policy measures such as increased enforcement and spending on restoration. Conversely, self-identified Republicans and individuals who view current regulations as ineffective tend to oppose governmental actions aimed at protecting and restoring Puget Sound. Support for one policy measure—tax credits for environmentally-friendly business practices—is not significantly affected by political party affiliation. These findings demonstrate that environmental awareness can influence public support for environmental policy tools. However, the nature of particular management interventions and other social forces can have important mitigating effects and need to be considered by practitioners attempting to develop environment-related social indicators and generate consensus around the need for action to address environmental problems.