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The Athabasca River basin, located in Alberta, Canada, covers 157, 000 km2 and holds significant cultural and economic importance. Recent research assessed changes in several water quality and quantity parameters that have changed both spatially (along the river continuum) and temporally (pre-development and present day) in the Athabasca River Basin. In particular, parameters such as salinity and dissolved sulphate have changed significantly across the Athabasca River mainstem over the past five decades. Further laboratory testing has linked concentrations of these parameters to changes in fathead minnow reproduction. Research is required to determine whether these changes observed in the laboratory can be applied to actual in-river conditions. The objectives of the present study were to twofold: assess changes in fathead minnow response metrics (i.e., condition, liver and gonad size, egg production, and gill histology) associated with increasing concentrations of salinity and dissolved sulphate and determine whether sublethal effect thresholds established in laboratory experiments correspond to actual in-river concentrations using water from the mouth and headwaters of the Athabasca River. Three dose−response experiments (NaCl, SO4, and water sampled from the mouth of the Athabasca River) were conducted at Jasper National Park, Alberta, Canada. Significant increases in mean eggs per female per day occurred at the 50% treatment for the mouth experiment and thresholds previously developed in the laboratory were verified. Environ. Toxicol. Chem. 2013;32:662-672. © 2012 SETAC [ABSTRACT FROM AUTHOR]

Abstract: We conducted a simulated nitrogen (N) and sulfur (S) deposition experiment in the Athabasca oil sands region (AOSR) where NO x and SO2 have been emitted from oil sands mining/extracting and upgrading activities and then deposited to the surrounding ecosystems for decades. To evaluate changes in tree growth rates, N pool sizes, and nutrient losses by S and N deposition, the following four treatments were applied: control (CK), N addition (+N, 30kgNha−1 yr−1), S addition (+S, 30kgSha−1 yr−1), and +NS additions (+NS, 30kgN and 30kgSha−1), from 2006 through 2009. Nitrogen addition increased (p <0.05) tree growth in the +N and +NS treatments, indicating N-limitation in the studied forest, while none of the treatments affected understory growth or soil microbial biomass. The treatments affected inorganic N concentrations in the soil only immediately following N addition. Minimal amounts of were leached below 45cm (considered to be below the main rooting zone) of the soil profile in any of the treatments. Decreases in exchangeable Ca2+ and Mg2+ by N and S additions were likely due to increased tree uptake following increased tree growth in the former and increased leaching with sulfate in the latter. Although the lack of significant N leaching indicates that the risk of N saturation was low after 4yr of elevated N deposition, reduction of exchangeable base cations implies that nutrient imbalance remains a concern in AOSR in the long term. [Copyright &y& Elsevier]

Souring in the Medicine Hat Glauconitic C field, which has a low bottom-hole temperature (30 °C), results from the presence of 0.8 mM sulfate in the injection water. Inclusion of 2 mM nitrate to decrease souring results in zones of nitrate-reduction, sulfate-reduction, and methanogenesis along the injection water flow path. Microbial community analysis by pyrosequencing indicated dominant community members in each of these zones. Nitrate breakthrough was observed in 2-PW, a major water- and sulfide-producing well, after 4 years of injection. Sulfide concentrations at four other production wells (PWs) also reached zero, causing the average sulfide concentration in 14 PWs to decrease significantly. Interestingly, oil produced by 2-PW was depleted of toluene, the preferred electron donor for nitrate reduction. 2-PW and other PWs with zero sulfide produced 95% water and 5% oil. At 2 mM nitrate and 5 mM toluene, respectively, this represents an excess of electron acceptor over electron donor. Hence, continuous nitrate injection can change the composition of produced oil and nitrate breakthrough is expected first in PWs with a low oil to water ratio, because oil from these wells is treated on average with more nitrate than is oil from PWs with a high oil to water ratio. [ABSTRACT FROM AUTHOR]

Abstract: The risk of soil acidification is high in the Athabasca oil sands region (AOSR) in Alberta, Canada, due to elevated SO2 emission and the resultant acid deposition to sensitive, coarse-textured soils. Understanding the sulfate adsorption characteristics of soils sensitive to acidification will help establish critical loads of acid deposition in AOSR. Sulfate adsorption properties were evaluated and relationships between sulfate adsorption and soil properties were examined for soils in two contrasting watersheds (NE7 and SM8) in AOSR. The experimental data fitted well to both the Langmuir and the Freundlich models. The sulfate adsorption capacity was greater for soils in SM8 than in NE7 (p <0.01), even though it was relatively low in both watersheds as compared to other acid-sensitive soils in eastern North America. Based on the additional sulfate adsorbed when a soil was treated with 40mL of 200mg L−1 solution, the weakly developed Podzolic B horizon (Bfj)in NE7 could adsorb more sulfate than the Ae horizon while no difference was found among other horizons. In SM8, the Bfj and illuviated B (Bt) horizons had greater ability to adsorb sulfate than the other horizons, likely caused by the presence of muscovite in the Bfj and Bt horizons. The additional sulfate adsorbed accounted for about 80% of the total sulfate adsorption capacity and was correlated with pHNaF (soil pH extracted with 1 MNaF) and ΔpHNaF(the difference between pHNaF and pH measured with deionized water), with the following relationships: sulfate adsorption (mg kg−1)=exp(2.03 pHNaF – 18.0)+50.2 (R 2 =0.63, p <0.001) and sulfate adsorption (mg kg−1)=exp(1.83 ΔpHNaF – 6.57) + 48.9 (R 2 =0.70, p <0.001). The ΔpHNaF was likely a better indicator of the soil’s sulfate adsorption capacity than pHNaF as the former excludes the effect of soil acidity. Our study indicates that the soil’s capacity to adsorb sulfate should be considered in determining the critical load for acid deposition in AOSR in Alberta. [Copyright &y& Elsevier]

Abstract: A regional groundwater geochemistry study was conducted in the Paskapoo Formation of southern Alberta, Canada. Our study area focused on a region where two continental ice sheets, the Cordilleran and Laurentide met. The glacial deposits transported by these ice sheets have different bulk characteristics reflective of the bedrock of the source region of the ice. Recharge through these two different glacial deposits generates distinctly different water geochemistry within the underlying Paskapoo Formation, such that bedrock aquifer acquires a geochemical signature of the immediately overlying glacial deposits through which recharge occurs. Oxidation of pyrite in Laurentide till generates high-sulphate groundwater, and associated acid generation leads to enhanced mineral weathering. This generates high TDS high Na–SO4 groundwater in underlying bedrock aquifers. This process appears transitory, where thin Laurentide drift deposits are completely oxidized and have reduced capacity to generate high-sulphate water. The same bedrock underlying carbonate dominated Cordilleran drift deposits have low TDS Ca–HCO3 groundwater. [Copyright &y& Elsevier]

The article presents a study which examines the ability of mineral soil and fibric peat from acid-sensitive western boreal catchments in Athabasca Oil Sands Region of Alberta to adsorb and release sulfate (SO42-). It says that five replicate mineral soils were gathered from A- and B-horizon soil at plots near the upland hillslope in each catchment while fibric peat was taken from a depth of 10 to 30 centimeters below the surface of the peat. It also states that laboratory experiments of the sample involve the determination of moisture content and pH. Results reveal that SO42- adsorption presents a limited reaction to elevated SO42- concentrations due to low iron and aluminum oxide content.

The objective of this paper is to outline how stable isotope techniques can contribute to the elucidation of the sources and the fate of riverine nitrate and sulphate in watershed studies. The example used is the Oldman River Basin (OMRB), located in southern Alberta (Canada). Increasing sulphate concentrations and decreasing δ34S values along the flowpath of the Oldman River indicate that oxidation of pyrite in tills is a major source of riverine sulphate in the agriculturally used portion of the OMRB. Chemical and isotopic data showed that manure-derived nitrogen contributes significantly to the increase in nitrate concentrations in the Oldman River and its tributaries draining agricultural land. It is suggested that hydrological conditions control agricultural return flows to the surface water bodies in southern Alberta and impart significant seasonal variations on concentrations and isotopic compositions of riverine nitrate. Combining isotopic, chemical, and hydrometric data permitted us to estimate the relative contribution of major sources to the total solute fluxes. Hence, we submit that isotopic measurements can make an important contribution to the identification of nutrient and pollutant sources and to river basin management. [ABSTRACT FROM AUTHOR]

Alberta is a major center for oil and gas production, and correspondingly harbors hundreds of unresolved contamination sites by environmental hazards such as benzene (C 6 H 6 ). Due to its cost-effectiveness, bioremediation has become a promising strategy for C 6 H 6 removal. Contamination sites typically take on an anaerobic context, which complicates the energetics of contamination sites and is a subject that is scarcely broached in studies of Albertan sediments. This study examines the innate potential for indigenous microbial communities in Albertan sediments to remove C 6 H 6 in a multitude of reduced conditions. Community profiles of these sediments were analyzed by 16S rRNA gene amplicon sequencing, and removal rates and reaction stoichiometries were observed by gas chromatography and ion chromatography. Organisms belonging to known primary degrader taxa were identified, including Geobacter (iron-reducing), and Peptococcaceae (nitrate-reducing). Furthermore, benzene removal patterns of the cultures were similar to those observed in previously reported microcosms, with lag times between 70 and 168 days and removal rates between 3.27 and 12.70 µM/day. Such information could support a more comprehensive survey of Albertan sediment consortia, which may eventually be utilized in informing future remediation efforts in the province. PRACTITIONER POINTS: ●Clay and sand sediments originating from Northern Alberta could remove benzene under methanogenic, sulfate-reducing, iron-reducing, and nitrate-reducing conditions. ●Degradation profiles were broadly comparable to those of reported cultures from other geographical locales. ●Key degrader taxa observed included Geobacter (Fe 3+ -reducing) and Peptococcaceae ( NO 3 - -reducing). ●Knowledge gained can be the start of a more extensive survey of Albertan sediments. Eventually, this collection of information can be used to generate robust C 6 H 6 -degrading cultures that can be implemented for bioaugmentation and be implemented in informing remediation strategies in soil and water matrices for priority contamination cases such as leaking underground storage tanks and orphan wells., (© 2020 Water Environment Federation.)