Dataset of 18O and 2H in streamflow across Canada: A national resource for tracing water sources, water balance and predictive modelling.

Oxygen-18 and deuterium were measured in streamflow samples collected from 331 gauging stations across Canada during 2013 to 2019. This dataset includes 9206 isotopic analyses made on 4603 individual water samples, and an additional 1259 analysis repeats for quality assurance/quality control. We also include arithmetic and flow-weighted averages, and other basic statistics for stations where adequate data were available. Station data are provided including station code, name, province, latitude, longitude and drainage area. Flow data were extracted from the historical database of the Water Survey of Canada. Details on the preliminary application of these data are provided in "18O and 2H in streamflow across Canada" [1]. Overall, these data are expected to be useful when combined with precipitation datasets and analytical or numerical models for water resource management and planning, including tracing streamflow source, water balance, evapotranspiration partitioning, residence time analysis, and early detection of climate and land use changes in Canada.

Watershed, climate, and stable isotope data (oxygen-18 and deuterium) for 50 boreal lakes in the oil sands region, northeastern Alberta, Canada, 2002-2017.

Watershed data, climate and stable data collected over a 16-year period from a network of 50 lakes in northeastern Alberta, are provided to allow for broader incorporation into regional assessments of environmental impacts, particularly hydrologic and geochemical processes under changing climate and land use development. Oxygen-18 and deuterium analyses of water samples are provided from late summer surveys of 50 lakes with varying land cover and permafrost conditions. Six sub-groups of lakes are represented, including Stony Mountains, West Fort McMurray, Northeast Fort McMurray, Birch Mountains, Caribou Mountains and Shield. This dataset includes 1582 isotopic analyses made on 791 water samples and 3164 isotope mass balance model outputs, as well as 800 lake/watershed parameters, 5600 climate parameters, and 800 modelled values for isotopic composition of precipitation used in the computations. Model data are provided to facilitate evaluation of transferability of the model for other applications, and to permit more sophisticated spatial analysis and intercomparison with geochemical and biological datasets. Details and further discussion on the isotope mass balance approach are provided in "Regional trends in water balance and runoff to fifty boreal lakes: a 16-year isotope mass balance assessment including evaluation of hydrologic drivers" [1]. Overall, the data are expected to be useful, in comparison with local and regional datasets, for water resource management and planning, including design of monitoring networks and environmental impact assessments for oil sands projects.

Stable isotope data (oxygen-18 and deuterium) from surveys of lakes, wetlands, rivers, and input waters across the South Athabasca Oil Sands region, Alberta, 2007-2009.

Oxygen-18 and deuterium analyses of water samples are provided from a regional survey of lakes, wetlands, soil waters, groundwaters, and snowpack samples collected in the Southern Athabasca Oil Sands (SAOS) region, Alberta, Canada, mainly during 2007-2009. Lake, wetland, and river sampling were conducted by helicopter during late summer, capturing conditions close to peak evaporative enrichment. Shallow soil water from the unsaturated zone was also collected in late summer, whereas deeper groundwaters from Quaternary aquifers, Quaternary channels, and uppermost Cretaceous strata, were collected primarily as part of winter drilling programs by industrial partners. Snowpack samples were collected in late March/early April, prior to significant spring melt. This dataset includes 1576 isotopic analyses made on 788 water samples as well as selected isotope mass balance model outputs (lake evaporation/inflow and water yield to lakes). These basic model data are provided to facilitate evaluation of the method as a tool for spatial mapping of water yield and its interannual variability. Details and further discussion on the isotope mass balance approach are provided in "Mapping water yield distribution across the southern Athabasca Oil Sands area: baseline surveys applying isotope mass balance of lakes" (Gibson et al., 2019). Overall, the data are expected to be useful, in comparison with local and regional datasets, for water resource management and planning, including design of monitoring networks and environmental impact assessments for oil sands projects.

Characterizing the PAHs in surface waters and snow in the Athabasca region: Implications for identifying hydrological pathways of atmospheric deposition.

The composition of polycyclic aromatic hydrocarbons present in snow and surface waters in the Athabasca Oil Sands Region (AOSR) was characterized in order to identify major contributors to the organics detected in rivers and lakes in the region. PAH concentrations, measured by three monitoring programs in 2011, were used to compare the PAH compositions of snow and surface waters across the AOSR. The 2011 dataset includes total (dissolved+particulate) concentrations of thirty-four parent and alkylated PAH compounds in 105 snow, 272 river, and 3 lake samples. The concentration of PAHs in rivers varies seasonally, with the highest values observed in July. The timing of increases in PAH concentrations in rivers coincides with the high river discharge during the spring freshet, indicating that this major hydrological event may play an important role in delivering PAHs to rivers. However, the composition of PAHs present in rivers during this period differs from the composition of PAHs present in snow, suggesting that direct runoff and release of PAHs accumulated on snow may not be the major source of PAHs to the Athabasca River and its tributaries. Instead, snowmelt may contribute indirectly to increases in PAHs due to hydrological processes such as erosion of stream channels, remobilization of PAH-containing sediments, increased catchment runoff, and snowmelt-induced groundwater inputs during this dynamic hydrologic period. Better understanding of transformations of PAH profiles during transport along surface and subsurface flow paths in wetland-dominated boreal catchments would improve identification of potential sources and pathways in the region. The compositional differences highlight the challenges in identifying the origins of PAHs in a region with multiple potential natural and anthropogenic sources particularly when the potential transport pathways include air, soil and water.

Characterization of organic composition in snow and surface waters in the Athabasca Oil Sands Region, using ultrahigh resolution Fourier transform mass spectrometry.

This study was conducted to characterize the composition of dissolved organic compounds present in snow and surface waters in the Athabasca Oil Sands Region (AOSR) with the goal of identifying whether atmospherically-derived organic compounds present in snow are a significant contributor to the compounds detected in surface waters (i.e., rivers and lakes). We used electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR MS) to characterize the dissolved organic compound compositions of snow and surface water samples. The organic profiles obtained for the snow samples show compositional differences between samples from near-field sites (<5 km from oil sands activities) and those from more distant locations (i.e., far-field sites). There are also significant compositional differences between samples collected in near-field sites and surface water samples in the AOSR. The composition of dissolved organic compounds at the upstream Athabasca River site (i.e., Athabasca River at Athabasca) is found to be different from samples obtained from downstream sites in the vicinity of oil sands operations (i.e., Athabasca River at Fort McMurray and Athabasca River at Firebag confluence). The upstream Athabasca River sites tended to share some compositional similarities with far-field snow deposition, while the downstream Athabasca River sites are more similar to local lakes and tributaries. This contrast likely indicates the relative role of regional snowmelt contributions to the Athabasca River vs inputs from local catchments in the reach downstream of Fort McMurray.