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Produced water is the largest waste stream associated with oil and gas exploration and production operations. Most produced water generated onshore is managed by permitted injection in deep underground wells, but alternative disposal options including reuse are increasingly being considered. However, insufficient understanding of the composition and toxicity of produced water imposes significant constraints on effective management of potential short‐term and long‐term risks associated with such alternative uses. As interest builds for management options, such as surface discharge, livestock watering, irrigation, and other industrial uses, research is needed to assess produced‐water hazards and exposures to both humans and the environment. This challenge affords an opportunity to capitalize on emerging risk assessment tools. Innovative and comprehensive approaches to filling data gaps and assessing produced water risks will be imperative. A group of experts from industry, academia, and government were assembled to define research needs to support objective decision making on the acceptability, or lack thereof, of produced water disposal alternatives. Presented here are key outcomes from that workshop and recommendations for a research framework to assess toxicity of produced water and associated risks from above ground discharge and reuse options. Integr Environ Assess Manag 2019;15:677–682. © 2019 SETAC. Key Points: In parts of the United States, permitted release of oil and gas wastewater (called produced water), either to surface waters or to land to supplement water requirements for livestock, agriculture, municipalities, or other industries is being actively implemented or investigated.Critical information gaps regarding the chemical characteristics and toxicity of produced water constituents limit efforts to comprehensively identify or mitigate potential hazards, leaving decision‐makers ill‐equipped to make informed choices with respect to produced water management.Monitoring strategies such as those for chemicals of emerging concern (CECs) for municipal wastewater recycling, and predictive chemical testing approaches (e.g., high‐throughput screening) often used to evaluate data‐poor chemicals can inform, and be integrated into, a produced water research strategy.The need to understand hazards and risks of produced water, provides a real‐world opportunity to explore how predictive chemical testing approaches may be integrated with other types of information for use by policy makers, regulators, operators, and end‐users. [ABSTRACT FROM AUTHOR]

Across the United States, road palliatives are applied to roads for maintenance operations that improve road safety. In the winter, solid rock salts and brine solutions are used to reduce the accumulation of snow and ice, while in the summer, dust suppressants are used to minimize fugitive dust emissions. Many of these products are chloride-based salts that have been linked to freshwater salinization, toxicity to aquatic organisms, and damage to infrastructure. To minimize these impacts, organic products have been gaining attention, though their widespread adoption has been limited due to their higher cost. In some states, using produced water from conventionally drilled oil and gas wells (OGPWs) on roads is permitted as a cost-effective alternative to commercial products, despite its typically elevated concentrations of heavy metals, radioactivity, and organic micropollutants. In this study, 17 road palliatives used for winter and summer road maintenance were collected and their chemical composition and potential human toxicity were characterized. Results from this study demonstrated that liquid brine solutions had elevated levels of trace metals (Zn, Cu, Sr, Li) that could pose risks to human and environmental health. The radium activity of liquid calcium chloride products was comparable to the activity of OGPWs and could be a significant source of radium to the environment. The organic fractions of evaluated OGPWs and chloride-based products posed little risk to human health. However, organic-based dust suppressants regulated toxicity pathways related to xenobiotic metabolism, lipid metabolism, endocrine disruption, and oxidative stress, indicating their use could lead to environmental harm and health risks to operators handing these products and residents living near treated roads. [Display omitted] • Road palliatives are used to improve road surfaces during winter & summer months. • Chloride-based brines had elevated levels of trace metals. • Calcium chloride brines had similar radium activity as oil & gas produced water. • Organic fraction of brines, oil & gas wastewater pose little risk to human health. • Organic-based dust suppressants strongly activated 4 toxicity pathways. [ABSTRACT FROM AUTHOR]

Lean-direct-injection (LD1) combustion is being considered at the National Energy Technology Laboratory as a means to attain low NOx emissions in a high-hydrogen gas turbine combustor Integrated gasification combined cycle (IGCC) plant designs can create a high-hydrogen fuel using a water-gas shift reactor and subsequent CO2 separation. The IGCC's air separation unit produces a volume of N2 roughly equivalent to the volume of H2 in the gasifier product stream, which can be used to help reduce peak flame temperatures and NOx in the diffusion flame combustor Placement of this diluent in either the air or fuel streams is a matter of practical importance, and it has not been studied to date for LDI combustion. The current work discusses how diluent placement affects diffusion flame temperatures, residence times, and stability limits, and their resulting effects on NOx emissions. From a peak flame temperature perspective, greater NOx reduction should be attainable with fuel dilution rather than air or independent dilution in any diffusion flame combustor with excess combustion air due to the complete utilization of the diluent as a heat sink at the flame front, although the importance of this mechanism is shown to diminish as flow conditions approach stoichio,netric proportions. For simple LDI combustor designs, residence time scaling relationships yield a lower NOx production potential for fuel-side dilution due to its smaller flame size, whereas air dilution yields a larger air entrainment requirement and a subsequently larger flame, with longer residence times and higher thermal NOx generation. For more complex staged-air LDI combustor designs, the dilution of the primary combustion air at fuel-rich conditions can result in the full utilization of the diluent for reducing the peak flame temperature, while also controlling flame volume and residence time for NOx reduction purposes. However, differential diffusion of hydrogen out of a diluted hydrogen/nitrogen fuel jet can create regions of higher hydrogen content in the immediate vicinity of the fuel injection point than can be attained with the dilution of the air stream, leading to increased flame stability. By this mechanism, fuel-side dilution extends the operating envelope to areas with higher velocities in the experimental configurations tested, where faster mixing rates further reduce flame residence times and NOx emissions. Strategies for accurate computational modeling of LDI combustors' stability characteristics are also discussed. [ABSTRACT FROM AUTHOR]

The article analyzes the reasons and nature of the lease for gas-works entered by the city of Philadelphia in Pennsylvania with the United Gas Improvement in 1898. It aims at examining the merits of public and private management. It is believed that the city government was bribed to accept the lease. The arguments made against the lease included that the city management might have earned profits. Provisions included in the lease contract are also presented in the article. The incident proved to be significant for the municipal development.

• Rapid investment into needles leaves Pinus palustris vulnerable to drought. • P. palustris operates closer to hydraulic failure and inhibits gas exchange earlier. • Potential tradeoff between fire and drought tolerance early on in ontogeny. Loblolly pine (Pinus taeda L.) has gradually replaced longleaf pine (P. palustris Mill.) across much of the coastal southeastern United States. Given recent interest in the regeneration of longleaf pine ecosystems, understanding how these two species will respond to drier conditions associated with climate change will be critically important. We conducted a progressive water-stress experiment on germinants of P. palustris and P. taeda over the course of 9 weeks, measuring gas exchange, allometry, water relations, and tracheid anatomy. P. palustris developed more overall biomass, had wider tracheids, allocated more of its biomass into leaf tissue, and maintained a narrower safety margin against hydraulic failure than P. taeda. Both species reduced leaf gas exchange as water stress increased, though P. palustris experienced earlier and greater declines in photosynthetic rates than P. taeda. The greater aboveground growth and narrower hydraulic safety margin observed in P. palustris represents a trade-off between growth and hydraulic safety and is likely related to the species' defensive strategy against fire. We suggest that this trade-off may limit P. palustris germinant regeneration on sandier, xeric sites as climate change intensifies. [ABSTRACT FROM AUTHOR]