Climate Change Canada Research Articles

Bluebirds Experience Impaired Hatching Success in Conventionally Sprayed Apple Orchard Habitats: A 31-Year Study.

We analyzed the reproductive success of eastern bluebirds (Sialia sialis) nesting in apple orchards and non‐orchard nest‐boxes in southern Ontario, Canada, from 1988 to 2018. Using data from 2397 nest‐boxes monitored at 20 orchard sites and 52 non‐orchard sites, we first modeled phenological parameters typically linked to climate change across both site types. We found that the first egg of each brood was laid significantly earlier in the season each year over our 31‐year study. Clutch initiation occurred 4 days earlier in the spring in 2018 compared to 1988. Average clutch size in the first or second brood did not change significantly during our 31‐year study; however, clutches were significantly smaller in orchards compared to non‐orchards (0.10 ± 0.03 fewer eggs between sites). Nests built in orchards were also at 6.1‐fold greater risk of parasitism and 2.1‐fold greater risk of depredation than nests in non‐orchards. After accounting for depredation and nest parasitism, hatching success was still significantly lower in orchards than in non‐orchards. Overall, hatching success was 4%–5% lower in orchards. The probability of successfully fledging did not differ significantly between site types. In 2012, a ban on use of the organophosphate insecticide azinphos‐methyl in orchards was enacted in Canada. We did not find a difference in hatching or fledging success in orchards after the ban. In our assessment of available data, we conclude that any pesticide effect on hatching success of eastern bluebirds in sprayed orchards is most likely the consequence of long‐term exposure to dichlorodiphenyltrichloroethane (DDT) compounds in orchard soils and bioaccumulation in eggs rather than pesticides in use since regulation of DDT in the 1970s. Environ Toxicol Chem 2021;40:3369–3378. © 2021 Her Majesty the Queen in Right of Canada. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. Reproduced with the permission of the Minister of Environment and Climate Change Canada.

Effects of quality controlled measured and re-analysed meteorological data on the performance of water temperature simulations

One of the most prominent sources of error and uncertainty in water quality modeling results is the input data. In this study, data from three meteorological databases were used to test the performance of a water temperature model of Lake Diefenbaker: the data from the Environment and Climate Change Canada (ECCC) had long-term quality control history (>20 years); the data from the AccuWeather had short-term quality control history (<10 years), and the data from the MeteoBlue database were modeled values. The CE-QUAL-W2 hydrodynamic and water quality model was used for this study. The models were calibrated by adjusting model coefficients controlling the amount of measured solar radiation and wind that reach the surface of the water. The sensitivity results showed very similar performances with slightly better performances (root mean square root difference of ±0.1) with the ECCC data followed by the MeteoBlue data and thereafter by the AccuWeather data respectively.

Are current tissue-based selenium guidelines and criteria overly protective of freshwater fish populations? A critical review with recommendations.

Several decades after selenium impacts on wild fish populations were observed in freshwater reservoirs receiving fly ash effluents from electric power facilities at Belews Lake and Hyco Reservoir (North Carolina, USA), developments in selenium (Se) toxicology have led to a greater understanding of Se effects on freshwater fish. These latter advancements have allowed regulatory agencies in several jurisdictions to develop tissue-based toxicity benchmarks for the protection of aquatic life. These benchmarks were generally derived from datasets encompassing multiple fish species and designed to protect the most sensitive species (US Environmental Protection Agency [EPA] water quality criteria). Safety factors have been applied in the development of some Canadian guidelines (British Columbia [BC]), resulting in guidelines that appear to be overly conservative. The present study addresses the question, "Are current tissue-based selenium guidelines and criteria overly protective of freshwater fish populations?" A literature review was conducted of studies in which Se was the primary constituent of concern, to compare tissue concentrations and results of fish population metrics and deformity assessment studies with current regulatory thresholds for the protection of aquatic life in the United States and Canada. EPA fish tissue-based Se criteria were found to be protective of fish populations and, at times, overly protective. Canadian water quality guidelines for Se (BC Ministry of Environment and Climate Change Strategy [BCMOECCS], Environment and Climate Change Canada [ECCC]) were consistently found to be overly protective, especially for benchmarks in which safety factors were used to derive those guidelines. In addition to a synthesis of the results of these studies, various limitations of the reviewed studies are discussed, and recommendations for future studies are proposed. Integr Environ Assess Manag 2022;18:622-630. © 2021 SETAC.

Air Quality Data Approach for Defining Wildfire Influence: Impacts on PM2.5, NO2, CO, and O3 in Western Canadian Cities

As the climate warms, it is recognized that wildfires are increasing in size and frequency. The negative effects of wildfires on air quality are well documented, especially on commonly monitored atmospheric pollutants such as PM2.5, NO2, CO, and O3. However, it is not clear how frequently wildfires influence urban air quality and the size of that influence relative to traffic and industrial pollutants. To understand the impact of wildfires on air quality, we have established an automated method to identify wildfire-influenced ambient air measurements. The trajectory-fire interception method (TFIM) compares hybrid single-particle Lagrangian integrated trajectory (HYSPLIT) back-trajectories from an air quality monitoring station to satellite imagery of fire "hot-spots" to determine the number of trajectory-fire interceptions that occur. From the number of interceptions and local PM2.5 measurements, we have defined a wildfire-influenced period to occur if the interception count is ≥20. TFIM wildfire identification compares favorably with Environment and Climate Change Canada's smoke forecast, FireWork, and with the BlueSky trajectory-based forecast. Using TFIM, we studied the impact of wildfire-influenced periods on PM2.5, NO2, CO, and O3 from 2001 to 2019 in Western Canadian urban areas. We show that wildfire-influenced periods have elevated concentrations of PM2.5, NO2, and CO but not O3. We show that a decreasing urban baseline of CO and NO2 over time results in a relatively greater impact of wildfires on these pollutants, which emphasizes the changing relative importance of wildfires on air quality.

A 10 km North American precipitation and land-surface reanalysis based on the GEM atmospheric model

Abstract. Environment and Climate Change Canada has initiated the production of a 1980–2018, 10 km, North American precipitation and surface reanalysis. ERA-Interim is used to initialize the Global Deterministic Reforecast System (GDRS) at a 39 km resolution. Its output is then dynamically downscaled to 10 km by the Regional Deterministic Reforecast System (RDRS). Coupled with the RDRS, the Canadian Land Data Assimilation System (CaLDAS) and Precipitation Analysis (CaPA) are used to produce surface and precipitation analyses. All systems used are close to operational model versions and configurations. In this study, a 7-year sample of the reanalysis (2011–2017) is evaluated. Verification results show that the skill of the RDRS is stable over time and equivalent to that of the current operational system. The impact of the coupling between RDRS and CaLDAS is explored using an early version of the reanalysis system which was run at 15 km resolution for the period 2010–2014, with and without the use of CaLDAS. Significant improvements are observed with CaLDAS in the lower troposphere and surface layer, especially for the 850 hPa dew point and absolute temperatures in summer. Precipitation is further improved through an offline precipitation analysis which allows the assimilation of additional observations of 24 h precipitation totals. The final dataset should be of particular interest for hydrological applications focusing on transboundary and northern watersheds, where existing products often show discontinuities at the border and assimilate very few – if any – precipitation observations.

The implications of permafrost thaw and land cover change on snow water equivalent accumulation, melt and runoff in discontinuous permafrost peatlands

AbstractIn the discontinuous permafrost zone of the Northwest Territories (NWT), Canada, snow covers the ground surface for half the year. Snowmelt constitutes a primary source of moisture supply for the short growing season and strongly influences stream hydrographs. Permafrost thaw has changed the landscape by increasing the proportional coverage of permafrost‐free wetlands at the expense of permafrost‐cored peat plateau forests. The biophysical characteristics of each feature affect snow water equivalent (SWE) accumulation and melt rates. In headwater streams in the southern Dehcho region of the NWT, snowmelt runoff has significantly increased over the past 50 years, despite no significant change in annual SWE. At the Fort Simpson A climate station, we found that SWE measurements made by Environment and Climate Change Canada using a Nipher precipitation gauge were more accurate than the Adjusted and Homogenized Canadian Climate Dataset which was derived from snow depth measurements. Here, we: (a) provide 13 years of snow survey data to demonstrate differences in end‐of‐season SWE between wetlands and plateau forests; (b) provide ablation stake and radiation measurements to document differences in snow melt patterns among wetlands, plateau forests, and upland forests; and (c) evaluate the potential impact of permafrost‐thaw induced wetland expansion on SWE accumulation, melt, and runoff. We found that plateaus retain significantly (p &lt; 0.01) more SWE than wetlands. However, the differences are too small (123 mm and 111 mm, respectively) to cause any substantial change in basin SWE. During the snowmelt period in 2015, wetlands were the first feature to become snow‐free in mid‐April, followed by plateau forests (7 days after wetlands) and upland forests (18 days after wetlands). A transition to a higher percentage cover of wetlands may lead to more rapid snowmelt and provide a more hydrologically‐connected landscape, a plausible mechanism driving the observed increase in spring freshet runoff.

QSTR and interspecies-QSTR modelling for aquatic toxicity data gap filling of cationic polymers

Polymers are extensively used in several fields representing a growing multi-billion dollar industry covering several thousands of materials and billions of kilos used globally every year. The widespread use of cationic polymers may significantly discharge such compounds into the aquatic environment, which may cause potential toxic effects on aquatic organisms. The amount of publicly available, high-quality environmental toxicity data for industrial polymers such as cationic polyquaterniums is low. We have developed here individual quantitative structure–toxicity relationship (QSTR) models for toxicity prediction against fish and algae. These models against fish and algae showed optimistic statistical quality in terms of several internal and external quality and validation metrics such as determination coefficient R2 (0.703 and 0.676), cross-validated leave-one-out Q2 (0.638 and 0.516) and predictive R2pred or Q2ext (0.776 and 0.703) for fish (Ntrain = 72, Ntest = 23) and algae (Ntrain = 40, Ntest = 14) toxicity datasets, respectively. The study revealed that higher charge density increases the toxicity against both the response endpoints. However, a higher percentage of oligomers with a molecular mass of lower than 1000 Daltons results in a decreased toxicity towards both the studied endpoints. Similarly, primary amines in the molecular building block result in a reduction in the toxicity against the algal species. However, acceptable individual QSTR models against D. magna could not be generated with the limited feature information obtained from the United States Environmental Protection Agency and additional data provided by Environmental Climate Change Canada (ECCC). Therefore, we have also proposed interspecies quantitative structure–toxicity relationship (i-QSTR) models among three species (D. magna, fish and algae species) to bridge the toxicity data gap for cationic polymers. The mechanistic interpretation of i-QSTR models revealed several important characteristic features of polymers along with the experimental response of one species which are also helpful for toxicity prediction of other species, ultimately helping to reduce the experimental testing for toxicity prediction. Finally, the proposed QSTR and i-QSTR models can be helpful to compute the toxicity of polymers in the early stages of screening for regulatory purposes and data gap filling for new or untested polymers falling within the applicability domain of the models.

Offshore wind can power Canada

As a maritime nation, Canada is the home to high-quality offshore wind resources. The assessment of Canada's offshore wind resources has a strategic significance for realizing its low-carbon future. This study focused on high-resolution and high-accuracy estimates of offshore wind resources over Canada using satellite-derived wind maps, e.g., CCMP (Cross-Calibrated Multi-Platform) images from 1988 to 2017. The CCMP derived wind speed and density were bias-corrected by ocean surface wind measurements collected from 63 stations located along the seas/lakes in Canada from 1987 to 2018. A series of consistent offshore wind resource maps were produced and analyzed. The results generated from CCMP were then compared with previous assessment (i.e., Environment and Climate Change Canada (ECCC)'s Wind Atlas) and proved to perform better in simulating wind speeds. We estimated the technically available offshore wind area, gross power capacity and gross potential over Canada. For example, a gross potential production of 20.348, 20.441, and 20.376 PWh/year were calculated using three commercial offshore wind turbines, i.e. GE 3.6s, REpower 5 M, and V164–8.0 over the calculated total gross offshore area of 1.053 million km2. It far exceeds the Canada's electricity consumption (i.e., 0.641 PWh) in 2018. In addition, most of the potential power productions are distributed in the Canadian Atlantic and Pacific Oceans, Hudson Bay and St Lawrence, with the mean wind speeds increasing from 1988 to 2017. This study can help to assess offshore wind resources and provide decision-makers with some scientific evidences for developing offshore wind in Canada.

Risk Assessment of Norovirus Illness from Consumption of Raw Oysters in the United States and in Canada.

Human norovirus (NoV) is the leading cause of foodborne illness in the United States and Canada. Bivalve molluscan shellfish is one commodity commonly identified as being a vector of NoV. Bivalve molluscan shellfish are grown in waters that may be affected by contamination events, tend to bioaccumulate viruses, and are frequently eaten raw. In an effort to better assess the elements that contribute to potential risk of NoV infection and illness from consumption of bivalve molluscan shellfish, the U.S. Department of Health and Human Services/Food and Drug Administration (FDA), Health Canada (HC), the Canadian Food Inspection Agency (CFIA), and Environment and Climate Change Canada (ECCC) collaborated to conduct a quantitative risk assessment for NoV in bivalve molluscan shellfish, notably oysters. This study describes the model and scenarios developed and results obtained to assess the risk of NoV infection and illness from consumption of raw oysters harvested from a quasi‐steady‐state situation. Among the many factors that influence the risk of NoV illness for raw oyster consumers, the concentrations of NoV in the influent (raw, untreated) and effluent (treated) of wastewater treatment plants (WWTP) were identified to be the most important. Thus, mitigation and control strategies that limit the influence from human waste (WWTP outfalls) in oyster growing areas have a major influence on the risk of illness from consumption of those oysters.

Chronic Embryo-Larval Exposure of Fathead Minnows to the Pharmaceutical Drug Metformin: Survival, Growth, and Microbiome Responses.

Metformin is a glucose‐lowering drug commonly found in municipal wastewater effluents (MWWEs). The present study investigated the chronic effects of metformin in early‐life stages of the fathead minnow (Pimephales promelas). Endpoints assessed were growth, survival, and deformities. The larval gut microbiome was also examined using 16 S ribosomal RNA gene amplicon sequencing to determine microbial community composition and alpha and beta diversity. Eggs and larvae were exposed to metformin measured concentrations (mean [standard deviation]) of 0.020 (0.017) μg/L (for controls) and 3.44 (0.23), 33.6 (1.6), and 269 (11) μg/L in a daily static‐renewal setup, with 20 embryos per beaker. The low and middle metformin exposure concentrations represent river and MWWE concentrations of metformin. To detect small changes in growth, we used 18 replicate beakers for controls and 9 replicates for each metformin treatment. Over the 21‐d exposure (5 d as embryos and 16 d posthatch [dph]), metformin did not affect survival or growth of larval fish. Hatch success, time to hatch, deformities in hatched fry, and survival were similar across all treatments. Growth (wet wt, length, and condition factor) assessed at 9 and 16 dph was also unaffected by metformin. Assessment of the microbiome showed that the larvae microbiome was dominant in Proteobacteria and Firmicutes, with small increases in Proteobacteria and decreases in Firmicutes with increasing exposure to metformin. No treatment effects were found for microbiome diversity measures. Control fish euthanized with the anesthetic tricaine methane sulfonate had decreased alpha diversity compared to those sampled by spinal severance. This experiment demonstrates that metformin at environmentally relevant concentrations (3.44 and 33.6 μg/L) and at 10 times MWWE concentrations (269 µg/L) does not adversely affect larval growth or gut microbiome in this ubiquitous freshwater fish species. Environ Toxicol Chem 2022;41:635–647. © 2021 Her Majesty the Queen in Right of Canada. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. Reproduced with the permission of the Minister of Environment and Climate Change Canada.

A Climate Change Impact Assessment (CCIA) of Key Indicators and Critical Thresholds for Viticulture and Oenology in the Fraser Valley, British Columbia, Canada

AbstractGrape growth and wine production are both closely connected with weather and climate, making anthropogenic climate change a source of great uncertainty for the grape and wine industries. To assess the impacts of climate change on viticulture and oenology in the Fraser Valley, British Columbia, Canada, where no such assessment has been published to this date, a series of key indicators and critical thresholds were selected based on their relevance to the local climatology. Trends among these indicators and thresholds were calculated over a historic period (1970-2019) and projected over the 21st century for one intermediate-emissions and one high-emissions climate change scenario. Historic trends were assessed using Environment and Climate Change Canada weather station data from Abbotsford, British Columbia. Two statistical downscaling methods were evaluated based on their ability to reproduce observed conditions in the Fraser Valley and the most effective method was used to create projections of local, daily climate change scenarios. During the historic period, temperatures increased significantly, while precipitation and moisture variables displayed insignificant trends, reflecting the trends observed across other wine regions in Canada and the Northwestern United States. Throughout the 21st century, warming is expected to continue while precipitation decreases modestly. Extreme heat is projected to become far more frequent, while extreme cold and potential frost days become rare. In the short term, modifications to vineyard and winery operations may be sufficient adaptation strategies. Over the long term, new grape varieties will most likely need to be planted in existing vineyards and suitability for cool-climate varieties may shift northward in direction or upward in elevation.

The Environment and Climate Change Canada Carbon Assimilation System (EC-CAS v1.0): demonstration with simulated CO observations

Abstract. In this study, we present the development of a new coupled weather and carbon monoxide (CO) data assimilation system based on the Environment and Climate Change Canada (ECCC) operational ensemble Kalman filter (EnKF). The estimated meteorological state is augmented to include CO. Variable localization is used to prevent the direct update of meteorology by the observations of the constituents and vice versa. Physical localization is used to damp spurious analysis increments far from a given observation. Perturbed surface flux fields are used to account for the uncertainty in CO due to errors in the surface fluxes. The system is demonstrated for the estimation of three-dimensional CO states using simulated observations from a variety of networks. First, a hypothetically dense, uniformly distributed observation network is used to demonstrate that the system is working. More realistic observation networks, based on surface hourly observations, and space-based observations provide a demonstration of the complementarity of the different networks and further confirm the reasonable behavior of the coupled assimilation system. Having demonstrated the ability to estimate CO distributions, this system will be extended to estimate surface fluxes in the future.

Effects of industrial effluent on wetland macroinvertebrate community structures near a wastewater treatment facility

Macroinvertebrate communities and environmental variables were examined in wetlands near an industrial wastewater treatment facility to assess impacts from exposure to historical effluents. Baseline wetland assessments were required prior to cleanup of contaminated sediments at the facility. The study included wetlands historically exposed to direct effluent discharge, wetlands exposed to current effluent discharge (at the time of sampling), and reference wetlands. Wetlands were sampled in June, July, and September 2018 using a new macroinvertebrate community monitoring protocol (“Wetland CABIN”) developed by Environment and Climate Change Canada. Macroinvertebrates were counted and identified to Family level. Data were qualitatively analyzed using pie charts and nonmetric multidimensional scaling, as well as quantitatively with the Shannon-Weiner diversity index, the Berger-Parker index and using pollution sensitivity values. Correlations using Spearman rho were also calculated between indices and measured environmental variables. Wetlands near the treatment facility were not significantly different compared to reference sites. Macroinvertebrate communities near the treatment facility appeared to be relatively unimpacted by historical effluent inputs. The Wetland CABIN protocol may be a useful monitoring tool for assessing wetland macroinvertebrate community structure because it allows for standardized approaches to be used to compare temporal changes at contaminated sites or spatially between sites.

Shoreline Contamination Report 2015 SS Arrow Spill Chedabucto Bay, NS, Canada

The 1970 SS Arrow incident in Chedabucto Bay, Nova Scotia (NS) was a milestone event in Canada's oil spill response history and has been used by Environment and Climate Change Canada (ECCC) for ongoing research for almost 50 years. In August of 2015, the remaining sunken section of the SS ARROW released Bunker C oil from its tanks and some sections of shorelines impacted in 1970 were affected once again. The Canadian Coast Guard led the 2015 response effort, which included Shoreline Clean-Up and Assessment Technique (SCAT) surveys, to evaluate the contamination on the shorelines of Chedabucto Bay. This poster presents an overview of the 1970 event as well as the shoreline contamination resulting from the 2015 release from the SS Arrow. It summarizes the SCAT survey results and the operational response of the ECCC's National Environmental Emergencies Centre (NEEC) in support of the incident.

A New Field Guide For Freshwater Shoreline Response

ABSTRACT Environment and Climate Change Canada (ECCC) has developed a series of field guides to provide technical support tools for decisions regarding the evaluation of freshwater and marine shorelines and treatment options during an oil spill response. The new Freshwater Shoreline Response Guide is aligned with and complements the most recent editions of the ECCC Shoreline Cleanup Assessment Technique (SCAT) Manual (ECCC, 2018) and the ECCC Field Guide to Oil Spill Response on Marine Shorelines (ECCC, 2016). ECCC is engaged to provide science-based information to the spill response community and develop an expertise in spill response. The purpose of the Freshwater Shoreline Response Field Guide is to provide advice and guidance on the protection and treatment of freshwater shorelines threatened or affected by an oil spill. This Field Guide focuses on conventional tactics normally available to responders and appropriate for freshwater shoreline environments. The content of the Field Guide is organized to describe key elements of: Health and safety for field teamsNet Environmental Benefit Analysis (NEBA) / Spill Impact Mitigation Assessment (SIMA)Freshwater environmentsOil fate and behaviour in freshwater environmentsResponse – planning, treatment, special topics, and completion and monitoring

The Multi-Partner Research Initiative: A Scientific Research Network to Support Decision Making in Oil Spill Response

ABSTRACT The Government of Canada's Oceans Protection Plan (OPP) is a comprehensive, transformative $1.5 billion strategy to build a world-leading marine safety system to protect marine ecosystems, while enabling inclusive economic growth. A key component of the OPP is the Multi-Partner Research Initiative (MPRI), led by Fisheries and Oceans Canada (DFO) in collaboration with other federal agencies (Environment and Climate Change Canada, Canadian Coast Guard, Natural Resources Canada, and Transport Canada), that aims to advance oil spill research by fostering a national/international research network that brings together scientific experts in the field. The core studies under this program are focused on the provision of scientific knowledge to support the development, validation and regulatory approval of Alternative Response Measures (ARMs) that include: spill treating agents, in situ burning, oil translocation and decanting/oily waste disposal. Additional research includes studies on key “cross-cutting” issues, such as natural attenuation and bioremediation of oil, assessment of toxic impacts associated with oil spills and the application of oil spill countermeasures, and oil detection and mapping by autonomous underwater vehicles (AUVs). The deliverables from this research program will provide essential information to support Net Environmental Benefit Analysis (NEBA) for decision making to select the optimal oil spill response option(s) to protect the marine environment and its living resources. With an emphasis on supporting the development of the next generation of scientists in the field through engagement with the private sector (i.e., spill response organizations and oil industry partners) and other international (e.g., USA, Norway, France, Australia, China) government agencies, MPRI is anticipated to have a profound influence on the oil spill research community and emergency response agencies within Canada and abroad.

Concentrations and loads of nutrients and major ions in the Niagara River, 1975–2018

Environment and Climate Change Canada has monitored Niagara River water quality in support of the Great Lakes Water Quality Agreement since establishing a fixed site at Niagara-on-the-Lake in 1975. Using over 40 years of data from this site along with the Fort Erie location added in 1983, we examine the status and trends of concentrations and loadings of nutrients and major ions and assess evidence of sources between the two stations. Trends were observed for the majority of measured parameters and there is strong agreement between trends in concentrations and loadings which are generally higher at the downstream site; however, upstream/downstream differences indicate relatively little loading occurs along the length of the river itself. For total phosphorus (TP), inputs from Lake Erie via the Niagara River account for the majority of loading to Lake Ontario and, in some years, exceed the 7000 MTA Lake Ontario target. Between 2014 and 2018, we calculate the mean Niagara River TP loading to be 5275 MTA. We highlight the major changes in water quality constituents over time, including TP, and reveal increased seasonal consumption of TP and SiO2, reflecting potential increases in the biological productivity in Lake Erie. The long and rich Niagara River dataset, which comprises year round sampling (including rare winter data), provides detailed tracking of changing Great Lakes water quality and could be further utilized to assess the impacts of climate change, improve understanding of diatom and harmful algal bloom dynamics, and enhance knowledge of in-lake major ion and nutrient dynamics.

In Vitro Screening of 21 Bisphenol A Replacement Alternatives: Compared with Bisphenol A, the Majority of Alternatives Are More Cytotoxic and Dysregulate More Genes in Avian Hepatocytes.

An avian in vitro screening approach was used to determine the effects of 21 bisphenol A (BPA) alternatives. Cytotoxicity and dysregulation of genes associated with estrogen response and other toxicologically relevant pathways evoked by these alternatives were compared with BPA. Most of the BPA alternatives (15/21) were equally or more cytotoxic than BPA in chicken embryonic hepatocytes; variability in cell viability was associated with chemical structure and the log octanol-water partition coefficient (logP) values. A negative linear relationship (r 2 = 0.745; p = 0.49-07 ; n = 18) was observed between logP and the log median lethal concentration (logLC50) values. The least cytotoxic BPA alternatives elicited the greatest gene dysregulation and, overall, most of the alternatives altered more genes than BPA (measured with a custom polymerase chain reaction array). This overall approach shows promise for use as a screen for hazard-based prioritization of BPA replacement alternatives and to ideally identify those that may be less harmful and/or require additional toxicity testing.Environ Toxicol Chem 2021;40:2026-2033. © 2021 Her Majesty the Queen in Right of Canada Environmental Toxicology and Chemistry © 2021 SETAC. Reproduced with the permission of the Minister of Environment and Climate Change Canada.

Evaluation of the snow cover in the Soil, Vegetation, and Snow (SVS) land surface model

AbstractThe Soil, Vegetation, and Snow (SVS) land surface model was recently developed at Environment and Climate Change Canada (ECCC) for operational numerical weather prediction and hydrological forecasting. This study examined the performance of the snow scheme in the SVS model over multiple years at ten well-instrumented sites from the Earth System Model-Snow Model Intercomparison Project (ESM-SnowMIP), which covers alpine, maritime and taiga climates. The SVS snow scheme is a simple single-layer snowpack scheme that uses the force-restore method. Stand-alone, point-scale verification tests showed that the model is able to realistically reproduce the main characteristics of the snow cover at these sites, namely snow water equivalent, density, snow depth, surface temperature, and albedo. SVS accurately simulated snow water equivalent, density and snow depth at open sites, but exhibited lower performance for subcanopy snowpacks (forested sites). The lower performance was attributed mainly to the limitations of the compaction scheme and the absence of a snow interception scheme. At open sites, the SVS snow surface temperatures were well represented but exhibited a cold bias, which was due to poor representation at night. SVS produced a reasonably accurate representation of snow albedo, but there was a tendency to overestimate late winter albedo. Sensitivity tests suggested improvements associated with the snow melting formulation in SVS.

Implementation of a semi-Lagrangian fully-implicit time integration of the unified soundproof system of equations for numerical weather prediction

AbstractAn alternate dynamical core that employs the unified equations of A. Arakawa and C.S. Konor (2009) has been developed within Environment and Climate change Canada’s GEM (Global Environmental Multiscale) atmospheric model. As in the operational GEM dynamical core, the novel core utilizes the same fully-implicit two-time-level semi-Lagrangian scheme for time discretization while the log-pressure-based terrain-following vertical coordinate has been slightly adapted. Overall, the new dynamical core implementation required only minor changes to the existing informatics code of the GEM model and from a computational performance perspective, the new core does not incur any significant additional cost. A broad range of tests – that include both two-dimensional idealized theoretical cases and three-dimensional deterministic forecasts covering both hydrostatic and non-hydrostatic scales–have been carried out to evaluate the performance of the new dynamical core. For all the tested cases, when compared to the operational GEM model, the new dynamical core based on the unified equations has been found to produce statistically equivalent results. These results imply that the unified equations can be adopted for operational numerical weather prediction that would employ a single soundproof system of equations to produce reliable forecasts for all meteorological scales of interest with negligible changes for the computational overhead.