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Successful reclamation and revegetation of disturbed sites depends on the availability of sufficient topsoil. Current regulations in western Canada require the replacement of =80% of the original topsoil depth (TRD) to restore pre-disturbance productivity. However, salvaged topsoil at many legacy and other disturbed sites is often insufficient to achieve the 80% TRD (TRD80). This 5-year study examined vegetation responses to 50% TRD without organic amendment (TRD50) or amended with either peat (PTRD50) or biochar (BTRD50), relative to the TRD80 treatment, following borrow site reclamation in northeastern Alberta, Canada. Amendments were applied once at rates calculated to bring organic carbon in the topsoil to concentrations approximating those in the TRD80 treatment. Tree and shrub seedling mixes were transplanted following amendment application and vegetation attributes were measured annually thereafter. Results showed that PTRD50 performed as well as TRD80 and outperformed BTRD50 with respect to native species' canopy cover and tree seedling height. Canopy covers of forb and non-native species decreased significantly whereas those of graminoid and native species increased over time for all treatments. Across treatments, native plant species richness increased by 5% per year while nonnative species richness decreased by 19% per year. Overall, peat showed a satisfactory rate of recovery and a trajectory toward the natural boreal forest, indicating its potential to improve reclamation success at disturbed boreal sites where salvaged soil is insufficient to attain equivalent land capability. This finding will provide an additional tool for regulators seeking to refine land reclamation guidelines for such sites in boreal forest regions. [ABSTRACT FROM AUTHOR]

Disturbed sites, such as borrow pits and oil and natural gas well sites, require reclamation to restore and sustain levels of productivity similar to those prior to the disturbance. However, salvaged topsoil at many sites is often insufficient to meet the 80% topsoil replacement depth (TRD80) required for successful reclamation in western Canada. This 5‐year study evaluated soil responses to 50% topsoil replacement depth without organic amendment (TRD50) or amended with either peat (PTRD50) or biochar (BTRD50), relative to the TRD80 treatment (Control), following borrow pit reclamation at a disturbed boreal site near Cold Lake, Alberta, Canada. Amendments were applied once at rates calculated to raise the soil organic carbon (SOC) content in the TRD50 soil to a level equal to that in the TRD80 treatment. Results showed a 143%, 87%, and 116% increase in total Kjeldahl nitrogen concentration in the PTRD50 relative to the TRD80, TRD50, and BTRD50 treatments, respectively, while soil potassium (K) concentration was significantly greater for BTRD50 than PTRD50. Peat and biochar significantly increased SOC concentrations by 83% and 88%, respectively, relative to the mean of TRD80 and TRD50 treatments. Our results show that peat and biochar can improve soil properties of disturbed boreal sites reclaimed with insufficient salvaged topsoil to a level suitable for successful reclamation. This has important implications on the reclamation of a multitude of disturbed sites, in Canada and globally, that have insufficient volumes of salvaged topsoil needed for successful reclamation. [ABSTRACT FROM AUTHOR]

Biomimetic extraction using solid‐phase microextraction is a passive sampling analytical method that can predict the aquatic toxicity of complex petroleum substances. The method provides a nonanimal alternative to traditional bioassays with the potential to reduce both vertebrate and invertebrate aquatic toxicity testing. The technique uses commercially available polydimethylsiloxane‐coated fibers that, following nondepletive extraction of water samples, are injected into a gas chromatograph with flame ionization detection. As the predictive nature of the method is operationally defined, it is critical that its application be harmonized with regard to extraction, analysis, and standardization parameters. Results are presented from a round robin program comparing the results from 10 laboratories analyzing four different sample sets of dissolved organics in water. Samples included two incurred oil sands process–affected waters and a cracked gas oil water accommodated fraction. A fourth sample of cracked gas oil blended in an oil sands process–affected water was analyzed to demonstrate the method's ability to differentiate between neutral and ionizable dissolved hydrocarbons. Six of the 10 laboratories applied an automated version of the method using a robotic autosampler where the critical extraction steps are precisely controlled and which permits batch screening of water samples for aquatic toxicity potential. The remaining four laboratories performed the solid‐phase microextraction manually. The automated method demonstrated good reproducibility with between‐laboratory variability across the six laboratories and four samples yielding a mean relative standard deviation of 14%. The corresponding between‐laboratory variability across the four laboratories applying the manual extraction was 53%, demonstrating the importance of precisely controlling the extraction procedure. Environ Toxicol Chem 2022;41:1613–1622. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

A critical element in building stronger health systems involves strengthening good governance to build capacity for transparent and fair health planning and priority setting. Over the past 20 years, the ethical framework Accountability for Reasonableness (A4R) has been a prominent conceptual guide in strengthening fair and legitimate processes of health decision-making. While many of the principles embedded within the framework are congruent with Western conceptualizations of what constitutes procedural fairness, there is a paucity in the literature that captures the degree of resonance between these principles and the views of decision makers from non-Western settings; particularly in Africa, where many countries have only recently, within the last 20-30 years, become more democratic. This paper contributes to the ethics literature by examining how Ethiopian decision makers conceptualize fair and legitimate health decision-making, and reflects on the degree of conceptual resonance between these views and the principles embedded in A4R. A qualitative case study approach from three districts in Ethiopia was undertaken. Fifty-eight decision makers from district, regional, zonal, and national levels were interviewed to describe their conceptualization of fairness and legitimacy in the district health planning process. Findings revealed that Ethiopians have a broad conception of fairness and legitimacy that while congruent with procedural justice, also aligned with principles of distributive and organizational justice. Researchers and practitioners seeking to strengthen procedural fairness in health priority setting must therefore recognize the significance of other philosophical dimensions influencing how fairness and legitimacy of health decision-making are constructed within the Ethiopian setting. [ABSTRACT FROM AUTHOR]

Abstract: Subsurface soil CO2 concentration is an important component of the terrestrial C budget and site specific information on the spatial and temporal variability and how it responds to forest management is needed for accurately estimating ecosystem C budgets. The objectives of this study were to examine the within site spatial and seasonal variability, and differences between sites of subsurface CO2 concentrations as affected by microtopography, clear cut harvesting, and soil texture. To address these objectives, we used two paired forested and clear cut sites of contrasting soil texture in Nova Scotia, Canada. The soil texture at the Lakevale pair (LF=intact forest and LCC=clear cut) was sandy while that of Pomquet (PF: intact forest and PCC=clear cut) was clayey. Two and half-years after clear cut harvesting, data were collected from each site on an approximately monthly time interval for 1 year from four mineral soil depths (0, 5, 20 and 35cm) and 10 microsites separated by approximately 10m and representing three local topographic features (level, trough and hump). We also monitored soil temperature and moisture with depth at a representative location at each site. Soil CO2 showed high within site variability and ranged between 346 and 28,086ppmv (median=2835) for LF, 319–29,135 (median=2802) for LCC, 364–29,016 (median=2345) for PF, and 407–81,053 (median=5690) for PCC. Differences due to microtopographic positions were not statistically significant (p >0.05). Median CO2 concentration and its variability generally increased with depth. Seasonally aggregated data indicated a distinct pattern with median CO2 concentrations as high as 8646ppmv (95% confidence interval=6937–12,142) during summer at PCC and as low as 1570ppmv (95% confidence interval=1290–1920) at LCC during winter. Despite the high within site variability, PCC showed significantly higher median CO2 concentration than PF. No significant difference in subsurface CO2 concentration was found between LF and LCC. Subsurface CO2 concentration showed significant quadratic correlation (R 2 =0.32–0.85, p <0.05) with soil temperature and volumetric water content only for the Lakevale sites, suggesting the presence of strong soil texture control on subsurface CO2 concentration dynamics at these sites. [Copyright &y& Elsevier]

The calcareous prairies of Louisiana have been threatened by the encroachment of woody plants, primarily eastern red cedar (Juniperus virginiana). The restoration and management of these rare plant communities require a thorough understanding of the soils supporting them. The knowledge of whether eastern red cedar encroachment has altered these soils is also of interest. We studied the depth distribution, at contrasting vegetation types (prairie, transition, forest) and landscape positions, of d15N, total N, organic C, C/N ratio, Ca, Mg, K and pH of three relict prairie-forest associations in north central Louisiana, USA. The effect of vegetation type was significant for soil d15N and Ca. Plant leaf samples from prairie, transition, and forest showed similar d15N signals, and mean values ranged between -1.6‰ and -1.1‰. The order of soil15N enrichment of the 0-10?cm depth relative to corresponding leaves was forest soil?>? transition soil?>?prairie soil. The forest soil was significantly enriched with15N compared with the prairie soil and transition soil. Except for C/N ratio, all the soil properties significantly decreased with depth while d15N increased with depth. Significant differences in C/N ratio, Ca and Mg were associated with landscape position. The change in soil pH due to woody encroachment was restricted to the 0-10?cm depth. The results suggest that the prairie soil was distinctly different from the forest soil and that the vegetation at transition (encroaching woody plants) was altering the surface soil pH towards ‘forest-like’ conditions. [ABSTRACT FROM AUTHOR]

Treatment wetlands have emerged as a potential remediation option for oil-sands process affected waters (OSPW) which contains a suite of organic and inorganic constituents of potential concern. The aim of this study was to evaluate the fate of metals in a treatment wetland exposed to OSPW. Data was collected over three operational seasons testing freshwater and OSPW inputs at the Kearl Treatment Wetland in northern Alberta. Overall, results show that OSPW from the Kearl oil sands mine has relatively low concentrations of metals and trace elements compared to other industrial OSPW. Of the inorganic constituents introduced into the wetland from OSPW, six analytes (As, Ba, Cu, Mo, Ni, and U) were found to depurate by wetland treatment, were distributed among wetland media (water, sediment, plants), and translocated into water sedge and cattail tissue. Depuration of these analytes from the OSPW occurred mainly through sorption to sediment, while Mo and Cu had higher uptake and storage within plant tissue compared to the other analytes. No significant differences in metal uptake were observed between cattails and water sedge; root concentrations were higher than leaf concentrations. Root and leaf concentration factors were similar across years indicating that mechanisms of plant uptake were not impacted by exposure to OSPW and that bioconcentration was mainly a function of exposure. These findings support continued investigation into the application of treatment wetlands for OSPW remediation and underscore the need for further studies to optimize these systems for diverse OSPW types.