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7. Report on research

Scientists from ECCC and HC conduct a wide range of research to inform the assessment and management of risks associated with various substances to human health or the environment. Frequently, scientists from other agencies and universities across Canada and the world collaborate with this research.

This section provides highlights of the research published in 2021-2022. The digital object identifier (DOI) or the International Book Standard Number (ISBN) has been provided for each research publication. To obtain online access to a particular publication, copy and paste the DOI (for example, DOI:17.1019/acs.est.1q03279) or ISBN into the search bar of your search engine. A comprehensive list of all research published in 2021-2022 has been included in the Annex.

7.1 Chemical substances

Research on chemical substances is designed to primarily:

HC also undertakes research to support the development of regulations and guidelines, with the goal of improving human health by reducing population exposure to pollutants.
During 2021-2022, research on chemicals was carried out by both departments under a number of programs, including the Chemicals Management Plan (CMP), the Northern Contaminants Program (NCP), the Strategic Technology Applications of Genomics in the Environment (STAGE) Program, Genome Canada and the Great Lakes Protection Initiative.

7.1.1 Environment and Climate Change Canada research

Environment and Climate Change Canada (ECCC) conducted research activities under the CMP as part of 21 projects. These projects were either new projects or a continuation of existing projects delayed by the pandemic and related suspension of laboratory and fieldwork. Some of the latter work was able to progress for those research projects conducted in partnership with universities that only experienced short shutdown periods. Municipal effluent studies included the characterization of toxic discharges related to textile mill inputs and the assessment of Selective Serotonin Reuptake Inhibitors (SSRIs) exposure to organisms in the receiving environment. Field and laboratory assessments of priority chemical substances including perfluoroalkyl substances, alkylbenzene sulfonates and lead in crustaceans, fish, mussels and frogs were also initiated. Significant progress was made for all research projects in terms of data analysis and publication of manuscripts. A selection of the papers related to chemicals in the environment published by ECCC scientists in 2021-2022 are referenced below.

7.1.1.1 Chemicals in the environment

Organic flame retardants and other priority substance

Focus of research: Global scale studies were conducted of the sources, levels and behavior in air, and risks to human health of organophosphate flame retardants and bisphenol A (BPA).

Results: A new methodology was presented for assessing the risks of airborne chemicals that includes the risks of any new products created by atmospheric chemical reactions of the parent chemical. It found that the transformation products of organophosphate flame retardants are distributed globally, representing a previously unrecognized exposure risk for the world's urban populations. Risk assessments of commercial chemicals should consider these atmospheric transformations.

Due to their low volatility, BPA and its analogues are mainly present in air associated with particles; this has important implications for their persistence in air and the role of particulate matter (especially microplastics) in their transport and deposition.

Publications: Liu, Q., Li, L., Zhang, X., Saini, A., Li, W., Hung, H., Hao, C., Li, K., Lee, P., Wentzell, J.J.B., Huo, C., Li, S.-M., Harner, T., Liggio, J. Uncovering global-scale risks from commercial chemicals in air, Nature, 600 (7889), pp. 456-461, DOI:10.1038/s41586-021-04134-6, 2021

Vasiljevic, T., Harner, T. Bisphenol A and its analogues in outdoor and indoor air: Properties, sources and global levels, Science of the Total Environment, 789, 48013, DOI: 10.1016/j.scitotenv.2021.148013, 2021

Microfibers and microplastics in the Canadian Arctic

Focus of research: The first Canadian Arctic-wide study of manmade particles in marine sediments collected from 14 sites between 2014 and 2017.

Results: Analysis of microfibers determined that 69% could be confirmed as manmade; of this 82% were microfibers (synthetic or modified cellulose such as from clothing material) and 15% were microplastics. The concentrations of manmade particles in dry sediment ranged from 0.6 to 4.7 particles per gram, which may exceed some concentrations recorded in urban areas near sources of plastic pollution, indicating that the Canadian Arctic is a “sink” where manmade fiber pollution collects.

Publication: Adams, J.K., Dean, B.Y., Athey, S.N., Jantunen, L.M., Bernstein, S., Stern, G., Diamond, M.L., Finkelstein, S.A. Anthropogenic particles (including microfibers and microplastics) in marine sediments of the Canadian Arctic, (2021) Science of the Total Environment, 784, art. no. 147155, DOI: 10.1016/j.scitotenv.2021.147155

Mercury

Focus of research: Describing mercury concentration trends over time, tracing racing mercury sources, transport and deposition and assessing the total mercury mass balance in the Arctic, highlighting the concerns of climate change on mercury in the Arctic environment and cryosphere, and assessing the impact of oils sands emissions on mercury levels.

Results: Over 98% of atmospheric mercury found in the Arctic is emitted outside of the region, and approximately 80 tonnes of mercury is transferred into the Arctic Ocean via rivers and coastal erosion per year. Atmospheric mercury deposition to the ocean and sedimentation may be underestimated by up to 100%. It was determined that sea ice melting, sea ice dynamics, thawing permafrost, ocean temperatures changes, and atmospheric processes have a significant impact on mercury cycling in the Arctic. It found that global mercury sources dominated the annual background mercury deposition in the Oil Sands region of Alberta, whereas oil sands mercury emissions made up a significant part of mercury deposition in the immediate vicinity of oil sands operations.

A number of ECCC scientists served as lead and contributing authors for the 2021 scientific assessment produced by the Arctic Monitoring and Assessment Programme (AMAP), which summarized current understanding of mercury in the Arctic, including drivers of mercury levels and the effects of mercury exposure on Arctic biota and human health. The assessment included an evaluation of numerous datasets to describe trends in mercury in the Arctic over the past 20-plus years, and a study of the sources, transport and deposition of mercury to and within the Arctic. Atmospheric levels in the Arctic are generally decreasing, possibly because of generally declining emissions from major sources closest to the Arctic, while both increasing and decreasing trends of mercury in Arctic biota have been observed over the last two decades. Contemporary human-created emissions and re-emission of historical mercury contamination (e.g. by wildfires) are major sources that are transported to the Arctic by the atmosphere, ocean currents, and rivers. The assessment provided updated information on long-range transport and deposition processes and advanced understanding of how mercury is stored and cycled within the Arctic environment.

Publications: Dastoor, A., Angot, H., Bieser, J., Christensen, J.H., Douglas, T.A., Heimbürger-Boavida, L.-E., Jiskra, M., Mason, R.P., McLagan, D.S., Obrist, D., Outridge, P.M., Petrova, M.V., Ryjkov, A., St. Pierre, K.A., Schartup, A.T., Soerensen, A.L., Toyota, K., Travnikov, O., Wilson, S.J., Zdanowicz, C. Arctic mercury cycling. Nat Rev Earth Environ 3, 270–286 (2022), DOI: 10.1038/s43017-022-00269-w

Steffen, A., Angot, H., Dastoor, A., Dommergue, A., Heimbürger-Boavida, L.-E., Obrist, D., and Poulain, A.: Mercury in the Cryosphere, Chapter 9. Advances in Atmospheric Chemistry. Volume 3: Chemistry in the Cryosphere, Part 2, 459–502 (2022), DOI: 10.1142/9789811230134_0009

Dastoor, A., Ryjkov, A., Kos, G., Zhang, J., Kirk, J., Parsons, M., and Steffen, A.: Impact of Athabasca oil sands operations on mercury levels in air and deposition, Atmos. Chem. Phys., 21, 12783–12807 (2021), DOI: 10.5194/acp-21-12783-2021

Morris, A.D., Rigét, F., Wilson, S., Steffen, A., Stupple, G. + 71 additional coauthors, AMAP Assessment 2021: Mercury in the Arctic, Chapter 2: Temporal Trends of Mercury in Arctic Media, Arctic Monitoring and Assessment Programme (AMAP), Tromsø, Norway, 2021.

Dastoor, A., Zhang, L. + 41 additional coauthors, AMAP Assessment 2021: Mercury in the Arctic, Chapter 3: Changes in Arctic Mercury Levels: Emissions Sources, Pathways and Accumulation, Arctic Monitoring and Assessment Programme (AMAP), Tromsø, Norway, 2021.

Polycyclic aromatic hydrocarbons (PAHs) and polycyclic aromatic compounds (PACs)

Focus of research: Characterizing PAHs in urban and semi-urban ambient air, and evaluating health risks by assessing the effects of PAC particle size on human exposure.

Results: A study investigated the contribution of 22 individual alkylated PAHs to the overall concentration and toxicity of PAHs in air in Toronto, Ontario, and found that these alkylated and gaseous PAHs - which are not routinely included in many air quality monitoring programs - have a significant toxic impact.

In a study assessing the particle size distribution of PACs in samples and its effects on human health, it was determined that skin contact exposure to PACs is comparable to inhalation, in terms of lifetime cancer risks, despite lower daily dermal exposure doses, implying that health impacts can be underestimated if only inhalation is considered.

Publications: Moradi, M., Hung, H., Li, J., Park, R., Shin, C., Alexandrou, N., Iqbal, M.A., Takhar, M., Chan, A., Brook, J.R.: Assessment of Alkylated and Unsubstituted Polycyclic Aromatic Hydrocarbons in Air in Urban and Semi-Urban Areas in Toronto, Canada, Environ. Sci. Technol. 2022, 56, 5, 2959–2967, DOI:10.1021/acs.est.1c04299

Tian, M., Liang, B., Zhang, L., Hu, H., Yang, F., Peng, C., Chen, Y., Jiang, C., Wang, J. Measurement of size-segregated airborne particulate bound polycyclic aromatic compounds and assessment of their human health impacts - A case study in a megacity of southwest China, Chemosphere, 2021, 284, art. no. 131339, DOI: 10.1016/j.chemosphere.2021.131339

Persistent organic pollutants (POPs) and chemicals of emerging Arctic concern (CEACs)

Focus of research: Reviewing the literature concerning unintentionally produced polychlorinated biphenyls (UP-PCBs), investigating the transport and circulation of various contaminants in the Arctic, and examining concentrations of hexachlorocyclohexane (a pesticide) in Lake Superior water.

Results: A review on the formation pathways and transport of UP-PCBs determined that dye and pigment manufacturing and industrial thermal processes produce UP-PCB emissions globally. UP-PCBs make up a significant proportion of total PCBs, from a few percent to 85%, and continues to increase.

Climate change is increasing the movement of contaminants such as POPs and CEACs within Arctic ecosystems; for example, melting glaciers and permafrost are releasing these contaminants into marine and freshwater ecosystems.

From 1986 to 2016, concentrations of two isomers of hexachlorocyclohexane were monitored in Lake Superior water. By 2016, only 2.7% and 7.9% of 1986 quantities remained of the two isomers. The primary removal process was volatilization, followed by degradation and outflow through rivers, while sedimentation was minor. The study emphasizes the success of regulatory controls on pesticides as well as the importance of long-term monitoring of chemicals in water to interpret removal processes and trends in biota.

Publications: Mastin, J., Harner, T., Schuster, J.K., South, L.: A review of PCB-11 and other unintentionally produced PCB congeners in outdoor air, Atmospheric Pollution Research, 13 (4), art. no. 101364, DOI:10.1016/j.apr.2022.101364

Hung, H., Halsall, C., Ball, H., Bidleman, T., Dachs, J., De Silva, A., Hermanson, M., Kallenborn, R., Muir, D., Sühring, R., Wang, X., Wilson, S.: Climate change influence on the levels and trends of persistent organic pollutants (POPs) and chemicals of emerging Arctic concern (CEACs) in the Arctic physical environment - a review, Environ. Sci.: Processes Impacts, 2022, DOI: 10.1039/D1EM00485A

Bidleman, T.F., Backus, S., Dove, A., Lohmann, R., Muir, D., Teixeira, C., Jantunen, L.: Lake Superior Has Lost over 90% of Its Pesticide HCH Load since 1986, Environ. Sci. Technol. 2021, 55, 14, 9518–9526, DOI: 10.1021/acs.est.0c07549

7.1.1.2 Chemicals and effects in wildlife, fish and associated food webs and ecosystems

Reviews of mercury and biological effects in exposed of Arctic biota

Focus of research: The Arctic Monitoring and Assessment Programme (AMAP) produced a scientific assessment of mercury in the Arctic in 2021. This AMAP report and related journal papers were made possible by data contributions and the involvement of international experts on mercury (in the Arctic) including numerous ECCC scientists. The chapters of this new mercury assessment have been revised and published as separate review articles in a peer-reviewed Special Issue of the journal Science of the Total Environment.

Results: Concerns about the risks posed by mercury to human health and the global environment led to the 2013 Minamata Convention on Mercury, which came into force in 2017. The Convention creates a global regulatory framework, introducing controls on mercury mining, emissions to air, land and water, and the phase-out of mercury use in a number of products and processes. The Arctic Monitoring and Assessment Programme (AMAP) has produced scientific assessments of mercury in the Arctic since 1998. The latest assessment AMAP Assessment 2021: Mercury in the Arctic, from which this summary is derived, updates the 2011 AMAP assessment that focused solely on mercury, as well as information presented in recent AMAP assessments of contaminant effects on Arctic wildlife (2018), and also introduces the latest information on mercury and human health in the Arctic. Information produced by AMAP, and the involvement of Indigenous Peoples and Arctic countries, were crucial in the negotiations leading up to the Minamata Convention, the preamble of which references “the particular vulnerabilities of Arctic ecosystems and Indigenous communities”. The Convention mandates ongoing assessment of its effectiveness, which requires monitoring of mercury pollution. This latest assessment from AMAP provides current scientific information and context that the international community will need to understand the impact of the Convention on the Arctic environment and people, and identifies additional research needed to minimize these impacts of mercury.

Publications: AMAP Assessment 2021: Mercury in the Arctic, ISBN – 978-82-7971-111-7, Report Chapters:

Changes over time and the influence of climate and weather factors on mercury in Hudson Bay polar bears, caribou, and seabird eggs

Focus of research: The focus of this research was on changes over time in total mercury (THg) levels in caribou (Rangifer tarandus groenlandicus) from the Qamanirjuaq herd, polar bears (Ursus maritimus), and thick-billed murre eggs (Uria lomvia), all from the Hudson Bay region. Climate/weather variables were modelled with THg levels over time to identify the factors of influence and to potentially improve temporal trends by modelling year. This research was the result of collaborations between ECCC (and other) Arctic researchers of the Northern Contaminants Program (CIRNAC), the Nunavut Department of Environment, and many Indigenous Peoples from the participating Nunavut communities.

Results: The changes over time of mercury in Arctic wildlife is presently inconsistent within and between species and are often insignificant, which limits data interpretation. The present study compared time series of THg concentrations in liver of polar bear (2007/08–2015/16), eggs of thick-billed murres (1993–2015) and kidney of caribou (2006–2015) from the Hudson Bay region of Canada and examined THg levels over time with available climate and weather data. Significant time trends of THg concentrations were not detected in any species. However, in multivariate models that included time-lagged sea ice freeze up dates, THg concentrations increased in Qamanirjuaq caribou. Sea ice conditions were also related to THg levels in polar bear liver but not those in eggs of murres, though year was not a significant factor. Greater precipitation levels one to two years prior to sampling were associated with greater THg concentrations in polar bears and caribou, likely due to greater deposition, flooding and discharge from nearby wetlands and rivers. Time-lagged Arctic and/or North Atlantic Oscillation (AO/NAO) indices also generated significant, inverse models for all three species, agreeing with relationships in other time series of similar length. The magnitude and direction of many relationships were affected by season, duration of time-lags, and the length of the time series. The findings support recent observations suggesting that temporal studies monitoring Hg in Arctic wildlife should consider including key climatic or weather factors to help identify consistent variables of influence and to improve temporal analyses of THg time series. This study helps to assess the effectiveness of regulations in connection to the Minamata Convention on Mercury, which depends on optimal interpretation of Hg time trends in high trophic level species.

Publication: Morris, A.D., Braune, B.M., Gamberg, M., Stow, J., O'Brien, J. and Letcher, R.J. 2022. Temporal change and the influence of climate and weather factors on mercury concentrations in Hudson Bay polar bears, caribou, and seabirds. Environmental Research, Vol., 207, Article #: 112169, DOI: /10.1016/j.envres.2021.112169

Climate change, mercury, perfluoroalkyl substances, linked to hormone, behavioural, and reproductive responses in Arctic seabirds

Focus of research: Arctic wildlife concurrently experience multiple stressors, including climate change and environmental contaminants. Some contaminants may disrupt hormones that govern wildlife behaviour and responses to climatic variations. Interactions of mercury, perfluoroalkyl acids, and other chemical pollutants, on hormones, foraging behaviours, and hatching success, were identified in a long-lived Arctic seabird, thick-billed murres (Uria lomvia), breeding in northern Hudson Bay (2016-2018). Murres are a species heavily reliant on sea-ice, and like other birds, their thyroid hormones (e.g., triiodothyronine) have important roles in metabolism, incubation, and thermoregulation. This study was a collaboration of ECCC research scientists (Kim Fernie, Robert Letcher, Birgit Braune) and colleagues and students of McGill University.

Results: Thick-billed murres were sampled in 2016 through 2018 while breeding in northern Hudson Bay. The murres had more mercury than legacy or replacement organic chemicals or pesticides. Mercury, thyroid hormones, and foraging behaviours of the birds, varied annually, and sea-ice breakup was 1-2 weeks earlier (2016, 2017) or similar (2018) to the 50-year average. When murres were likely already stressed due to early sea-ice breakup (2016, 2017), their blood mercury levels influenced circulating triiodothyronine, that in turn, reduced the birds’ foraging time underwater. It was concluded that when sea-ice breaks up early in the breeding season, mercury may interfere with the ability of murres to adjust their foraging behaviour, via thyroid hormones, to varying sea-ice conditions. 

Perfluoroalkyl acid pollutants also occurred in the blood of the same murres, and were higher in females than males likely reflecting feeding differences. Several of these chemicals altered circulating triiodothyronine in males, and were negatively associated with the birds’ body weight. Some perfluoroalkyl acids were also related negatively to when their eggs hatched, possibly from disrupting the birds’ incubation behaviour that led to earlier hatch dates. This study concluded that as an Arctic seabird experiencing several indirect effects of climate change, the interaction of perfluoroalkyl acid pollutants on the thyroid activity of the birds, may cause additional stress to murres.

Publications: Esparza, I., Elliott, K.H., Choy, E.S., Braune, B.M., Letcher, R.J., Patterson, A., Fernie, K.J. Mercury, legacy and emerging POPs, and endocrine-behavioural linkages: implications of Arctic change in a diving seabird. Environmental Research. volume 212A, 2022, 113190,  DOI:10.1016/j.envres.2022.113190

Choy, E.S., Elliott, K.H., Esparza, I., Patterson, A., Letcher, R.J. Fernie, K.J. Potential disruption of thyroid hormones by perfluoroalkyl acids in an Arctic seabird during reproduction. Environmental Pollution volume 305, 2022, 119181, DOI:10.1016/j.envpol.2022.119181

Review of climate change and the flow of persistent organic chemical pollutants through Arctic food webs

Focus of research: The Arctic Monitoring and Assessment Programme (AMAP) produced a scientific assessment of the influence of global climate change on persistent organic pollutants (POPs) and chemicals of emerging Arctic concern (CEACs) in 2021, including a chapter on the accumulation and toxicity of these chemicals in Arctic food webs. This AMAP report and related journal review papers, was made possible by the involvement of international experts on persistent organic pollutants (in the Arctic) including numerous ECCC scientists and as well as many Indigenous Peoples from the participating communities across many national and international jurisdictions. The chapters of this new climate change-persistent organic pollutants assessment are published as separate review articles in a peer-reviewed Special Issue of the journal Environmental Science: Processes and Impacts.

Results:  Concerns regarding the exposure, accumulation and toxicity of POPs and CEACs to wildlife, human health and the global environment, led to the U.N. Stockholm Convention on Persistent Organic Pollutants (1972). The Convention creates a global regulatory framework, introducing controls on the production and use of POPs and CEACs, their emissions to the environment, and the phasing-out of multiple chemical pollutants used in various products and processes. The Arctic Monitoring and Assessment Programme (AMAP) has contributed to the Stockholm Convention via its scientific assessments of POPs and CEACs in the Arctic since 1998. This new report summarizes the current understanding of how climate change influences natural processes that in turn affect POPs and CEACs, including in Arctic wildlife and food webs. Climate change interacts with other environmental stressors to impact contaminants and their toxicity to multiple Arctic wildlife species, populations and ecosystems; these stressors include physical climate parameters (e.g., climate oscillation indices, precipitation, water salinity, sea-ice age and quality), thawing of permafrost, species moving northward leading to changes in food webs. Although collectively understudied, these and other multiple stressors may cumulatively affect some Arctic wildlife populations. Global regulations and climate change can influence POPs and CEACs, but more information on a broad range of habitats, species, and processes, is required to better understand the consequences of climate change to the distribution, accumulation, and effects of POPs and CEACs in the Arctic.

Publication: Borgå, K., McKinney, M., Routti, H., Fernie, K.J., Giebichenstein, J., Muir, D., Hallanger, I. The influence of global climate change on accumulation and toxicity of POPs and CEACs in Arctic food webs: A review. Environmental Science: Processes and Impacts (Special Issue). 2022, DOI: 10.1039/D1EM00469G

A review of metabolic transformation of brominated flame retardants in wildlife

Focus of research: The focus of this review initiative was to carry out a comprehensive and systematic review of all of the available literature information since 2015 regarding the non-human animal-mediated biotransformation and metabolism of brominated flame retardant (BFR) contaminants in global wildlife, and critically evaluate the current and key knowledge gaps and research needs. This review was a collaboration of an ECCC research scientist (Robert Letcher), his PhD student (Tristan Smythe), and colleagues at the University of Stockholm, Sweden (Ake Bergman) and Nanjing University of Science and Technology, P.R. China (Guanyong Su).

Results: Over the past few decades, production trends of the flame retardant (FR) industry, and specifically for brominated FRs (BFRs), is for the replacement of banned and regulated compounds with more highly brominated, higher molecular weight compounds including polymeric compounds. Chemical, biological, and environmental stability of BFRs has received some attention over the years but knowledge is currently lacking in the transformation potential and metabolism of replacement emerging or novel BFRs (E/NBFRs). For articles published since 2015, a systematic search strategy reviewed the existing literature on the direct (e.g., in vitro or in vivo) non-human BFR metabolism in fauna (animals). Of the 51 papers reviewed, and of the 75 known environmental BFRs, PBDEs were by far the most widely studied, followed by HBCDDs and TBBPA. Experimental protocols between studies showed large disparities in exposure or incubation times, age, sex, depuration periods, and of the absence of active controls used in in vitro experiments. Species selection emphasized non-standard test animals and/or field-collected animals making comparisons difficult. For in vitro studies, confounding variables were generally not taken into consideration (e.g., season and time of day of collection, pollution point-sources or human settlements). As of 2021 there remains essentially no information on the fate and metabolic pathways or kinetics for 30 of the 75 environmentally relevant E/BFRs. Regardless, there are clear species-specific and BFR-specific differences in metabolism and metabolite formation (e.g. BDE congeners and HBCDD isomers). Future in vitro and in vivo metabolism/biotransformation research on E/NBFRs is required to better understand their bioaccumulation and fate in exposed organisms. Also, studies should be conducted on well characterized lab (e. g., laboratory rodents, zebrafish) and commonly collected wildlife species used as captive models (crucian carp, Japanese quail, zebra finches and polar bears).

Publication: Smythe, T.A., Su, G., Bergman, Å., Letcher, R.J. 2022. Metabolic transformation of environmentally relevant brominated flame retardants in fauna: A review. Environment International. Vol. 161, Article #: 107097, DOI: /10.1016/j.envint.2022.107097

Organophosphate diesters and a review of sources, chemical properties, environmental occurrence and adverse effects

Focus of research: The present review examined all organophosphate diesters (OPs) that have been reported in the scientific literature up to the end of 2020. The primary objectives were 1) to summarize all OP diesters that have been reported and to analyze their potential characteristics in environments; 2) to characterize their potential sources; 3) to summarize the occurrence and distribution of OP diesters in different environmental matrices; and 4) to discuss the current knowledge regarding the adverse effects from OP diesters in exposed animals or humans. This review was a collaboration of an ECCC research scientist (Robert Letcher) and colleagues and students at Nanjing University of Science and Technology, P.R. China (Guanyong Su).

Results: In recent years, environmental scientists have proven that OP diesters widely exist in a variety of environmental matrices and biotic samples around the world, implying the potential risks from OP diester exposure to biota and humans in the environment. The present paper reports on the review of the scientific literature for studies involving OP diesters and up to the end of 2020. The aim was to assess the present understanding of the physicochemical properties, sources (industrial production and degradation), environmental occurrence of OP diesters, and adverse effects to exposed organisms. In screening the literature at least 23 OP diesters have been reported as contaminants in various environments or as degradation products of OP triesters. The physicochemical properties of OP diesters vary depending on their specific chemical structures. There were multiple sources of OP diesters, including industrial production and biotic or abiotic degradation from OPE triesters. Ten OP diesters are produced somewhere in the world, and the total annual output was estimated to be 17,050 metric tons. The wide application of OP triesters worldwide makes the degradation of OP triesters another critical source of OP diesters to the environment and to organisms. Current monitoring studies have demonstrated that some OP diesters were detectable in the human body (via both blood and urine samples), indoor dust, natural/wastewater, sewage sludge, or organisms worldwide. The adverse effects following direct or indirect exposure to 11 OP diesters in organisms (including animals, humans, bacteria, and algae) have been reported, and the recorded adverse outcomes following exposure to OP diesters included developmental toxicity, alteration of gene expression, and disturbance of nuclear receptor activity. Biomonitoring studies regarding human samples have frequently reported statistically significant associations between the concentrations of OP diesters and markers of human health (mainly related to reproductive toxicity).

Publication: Liu, Y., Gong, S., Ye, L., Li, J., Liu, C., Chen, D., Fang, M., Letcher, R.J., Su, G. 2021. Organophosphate (OP) Diesters and a review of sources, chemical properties, environmental occurrence, adverse effects, and future directions.  Environment International. Vol.155, Article #: 106691, DOI: 10.1016/j.envint.2021.106691

Evaluating using insect-eating birds to monitor microplastics in the terrestrial environment

Focus of research:  Microplastics are some of the most ubiquitous environmental pollutants globally. To date, most microplastics research has focused on marine and freshwater ecosystems with only limited research investigating microplastics in terrestrial ecosystems and biota. This study investigated the presence of microplastics (over 125 μm) in tree swallow (Tachicyneta bicolor) chicks, an aerial insectivore bird whose diet involves insects from terrestrial and/or freshwater sources. Comparisons were made between tree swallow chicks that were raised immediately downstream (300 m) of the discharge pipe of a large, urban wastewater treatment plant (WWTP) or 40 km away at a rural conservation area. The study was a collaboration between ECCC research scientists (Kim Fernie, Jennifer Provencher) and the University of Toronto.

Results: Anthropogenic microparticles, including microplastics, were identified in nearly 90% of chicks raised downstream of the wastewater treatment plant and 83% of the reference chicks. All microparticles were fibers in the gastro-intestinal tracts of chicks raised near the wastewater treatment plant, whereas unexpectedly, microparticles were more diverse in the gastro-intestinal tracts of reference chicks, with ~15% characterized as pre-production plastic pellets. The feces of 90% of all chicks contained microparticles that were all fibers, suggesting their excretion by the chicks. Comparatively, the reference chicks had more microparticles in their feces and larger particles in their gastro-intestinal tracts, likely reflecting their more aquatic-based diet compared to the more terrestrial-based diet of the chicks raised downstream of the wastewater treatment plant. The numbers of microparticles were not associated between the chicks' gastro-intestinal tracts and feces, nor with the chicks' body condition or size (weight, organs, feathers). Recommendations included sampling macroinvertebrate prey to permit stronger conclusions regarding wastewater treatment plants as possible sources of microplastics for swallows, and to determine if such macroinvertebrates may be a non-lethal method to characterize microparticle diversity ingested by birds as presently identified in the chicks' gastro-intestinal tracts. It was concluded that sampling feces only, while not indicative of the diversity of microplastics ingested by terrestrial passerines (e.g., tree swallows), is useful for determining their exposure to microparticles.

Publication: Sherlock, C., Fernie, K.J., Munno, K., Provencher, J., Rochman, C. The potential of aerial insectivores for monitoring microplastics in terrestrial environments. Science of the Total Environment volume 807, 2022, 150453, DOI:10.1016/j.scitotenv.2021.150453

Effects of neonicotinoid insecticides on non-target aquatic organisms

Focus of research: The study assessed the effects of neonicotinoid insecticides on tadpole stress metrics to understand the sublethal effects of chronic exposure to these compounds on sensitive non-target vertebrates. Specifically, blood cell profiles, measures of oxidative stress, susceptibility to parasites and concentrations of a stress hormone, corticosterone were assessed

Results: Northern leopard frogs (Rana (Lithobates) pipiens) were found to show signs of mild stress based on blood cell profiles and some indication for oxidative damage when exposed to clothianidin (a neonicotinoid). Furthermore, thiamethoxam (also a neonicotinoid) altered some blood cell profiles, but neither clothianidin nor thiamethoxam affected corticosterone concentrations or parasite infection status. These studies indicate that northern leopard frog tadpoles exposed to some neonicotinoids for prolonged periods have increased stress responses, but the implications on overall health are unclear. This work contributes to understanding the global concern for neonicotinoid insecticides on non-target aquatic vertebrates and will inform regulations for this pesticide product.

Publications: Gavel, M.J., Young, S.D., Dalton, R.L., Soos, C., McPhee, L., Forbes, M.R., Robinson, S.A. 2021. Effects of two pesticides on northern leopard frog (Lithobates pipiens) stress metrics: Blood cell profiles and corticosterone concentrations. Aquatic Toxicology 235:105820 DOI:10.1016/j.aquatox.2021.105820

* This work was conducted in collaboration with Carleton University

Gavel, M.J., Young, S.D., Blais, N., Forbes, M.R., Robinson, S.A. Trematodes coupled with neonicotinoids: effects on blood cell profiles of a model amphibian. Parasitology Research 120 (6): 2135-2148. DOI:10.1007/s00436-021-07176-x

* This work was conducted in collaboration with Carleton University

Robinson, S.A., Chlebak, R.J., Young, S.D., Dalton, R.L., Gavel, M.J., Prosser, R.S., Bartlett, A.J., de Solla, S.R. Clothianidin alters leukocyte profiles and elevates measures of oxidative stress in tadpoles of the amphibian, Rana pipiens. Environmental Pollution 284:117149 DOI: 10.1016/j.envpol.2021.117149

* This work was conducted in collaboration with Carleton University

Evaluation of thyroid disrupting activities of a synthetic phenolic antioxidant

Focus of research: The study assessed the effects of the synthetic phenolic antioxidant 4,4'-thiobis(6-t-butyl-m-cresol) (acronym TBBC) used in a variety of common plastic and rubber products to extend product life from oxidation (e.g., reduce discolouration, rust formation, rubber degradation). The western-clawed frog (Silurana tropicalis) was used to determine if embryo survival and development were affected after 96 hours of exposure or if the compound affected metamorphic development of tadpoles after 48 to 52 days of exposure.

Results: Acute 96-hour exposures determined the lethal concentration for 50% mortality (LC50) was 70.5 µg/L and the effective concentration for 50% with malformations (EC50) was 76.5 µg/L. Exposure concentrations from 25 to 100 µg/L affected embryo growth with complete mortality at 200 and 400 µg/L. Chronic exposure to 5 µg/L reduced body size by 8% snf sy 0.002 µg/L reduced body mass by 17% compared to clean water control treatments. This study provides the first amphibian toxicity assessment of TBBC, where it was found to be toxic, induce malformations and inhibit tadpole growth after acute and chronic exposures. The results will contribute to the risk assessment for this compound and inform future toxicity studies on synthetic phenolic antioxidants.

Publication: Reyes, Y.M., Robinson, S.A., De Silva, A., Brinovcar, C., Trudeau, V.L. Exposure to the synthetic phenolic antioxidant 4,4'-thiobis(6-t-butyl-m-cresol) disrupts early development in the frog Silurana tropicalis. Chemosphere, DOI: 10.1016/j.chemosphere.2021.132814

* This study was conducted in collaboration with the University of Ottawa.

Toxicity of rare earth elements in rainbow trout and hydra

Focus of Research: To determine the toxicity and the mechanism of action of rare earth elements

Results: The toxicity and mode of action for over 10 rare earth elements were examined in rainbow trout and hydra. The lethal toxicity could be predicted by the electronegativity and ionic radius in fish and hydra. The mode of action studies revealed that rare earth elements could damage (denature) proteins, alter bone formation and damage DNA at concentrations 200 times below the acute toxicity values.

Publications: Hanana, H., Taranu, Z.E., Turcotte, P., Gagnon, C., Kowalczyk, J., Gagné, F. 2020.  Evaluation of general stress, detoxification pathways, and genotoxicity in rainbow trout exposed to rare earth elements dysprosium and lutetium. Ecotoxicology and Environmental Safety, 2021, 208, 111588

Hanana, H., Taranu, Z.E., Turcotte, P., Kowalczyk, J., Gagné, F. 2021.  Sublethal effects of terbium and praseodymium in juvenile rainbow trout.  Science of the Total Environment, 2021, 777, 146042

7.1.1.3 Nanomaterials

Occurrence and size distribution of silver nanoparticles in wastewater effluents from various treatment processes in Canada

Focus of research: The objective of this investigation was to examine the occurrence and the size distribution of Silver (Ag) released from municipal effluents. From an environmental risk management perspective, it is important to better understand the size distribution of Ag released in nanoparticle (NP) form since NPs could possess different toxicities than their bulk ionic counterpart (i.e., Ag (I) because of the high surface area and reactivity). This is the first study on the characterization of NP Ag releases from different WWTPs using single particle-mode Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), a technique adapted for the specific detection of NPs.

Municipal effluents from ten municipalities using different treatment processes (from aerated lagoons to advanced biological treatments), were sampled across Canada. Moreover, untreated wastewaters were also collected to determine the overall Ag removal at WWTPs.

Results: ECCC's results showed the presence of silver nanoparticles (Ag NP) in all effluent samples with concentrations reaching 0.5 ng/L on a mass basis. However, on a particle number basis, Ag NP concentrations (expressed in particles/mL) in the 20-34 nm fraction (up to 3400 particles/mL) were much more abundant (>700%) than in the >35 nm larger fraction. The proportion of Ag at the nanoscale (1-100 nm) represents less than 8% of the total suspended Ag for all effluent samples. Because Ag nanotoxicity is size dependent, the determination of size distribution and exposure concentration on a particle number basis (i.e., number instead of mass) could be a useful focus when conducting risk assessments of this class of nanomaterial. 

Publication: Gagnon C, Turcotte P, Gagné F, Smyth SA. 2021. Occurrence and size distribution of silver nanoparticles in wastewater effluents from various treatment processes in Canada. Environ Sci Pollut Res. 28 : 65952–65959. DOI: 10.1007/s11356-021-15486-x

7.1.2 Health Canada Research

HC funded 24 CMP Research and Monitoring and Surveillance projects in 2021-2022. These projects addressed departmental and international priorities and covered a number of subjects such as:

7.1.2.1 Chemical substances in Canadians

National Biomonitoring Program under the Canadian Health Measures Survey (CHMS)

Focus of research: Canadian Health Measures Survey (CHMS) is a national survey led by Statistics Canada, in partnership with Health Canada and the Public Health Agency of Canada. The physical measures component of the survey includes biomonitoring, the measurement of environmental chemicals or their metabolites in blood, urine and/or hair samples, funded and led by Health Canada's National Biomonitoring Program. Since 2007, the National Biomonitoring Program has established baseline concentrations for over 250 environmental chemicals in Canadians supporting the identification of risk assessment priorities, characterization of exposures in risk assessments, performance measurement of recent risk management actions, while also serving as the basis of numerous scientific research studies. 

Results: Significant monitoring and research activities of the National Biomonitoring Program for 2021-2022 included:

Publications: Pollock, T., Karthikeyan, S., Walker, M., Werry, K., St-Amand, A. 2021. Trends in environmental chemical concentrations in the Canadian population: Biomonitoring data from the Canadian Health Measures Survey 2007-2017. Environment International. Vol.155, 106678, DOI: 10.1016/j.envint.2021.106678

Health Canada. 2021. Sixth report on human biomonitoring of environmental chemicals in Canada.Minister of Health, Ottawa, ON. ISBN : 2562-9360  

Health Canada. 2021. Arsenic in Canadians. Ottawa, ON. ISBN: 978-0-660-40587-2

Health Canada. 2021. Cadmium in Canadians. Ottawa, ON. ISBN: 978-0-660-40591-9

Health Canada. 2021. Lead in Canadians. Ottawa, ON. ISBN: 978-0-660-40595-7

Health Canada. 2021. Mercury in Canadians. Ottawa, ON. ISBN: 978-0-660-40597-1

Health Canada. 2021. Per- and polyfluoroalkyl substances (PFAS) in Canadians. Ottawa, ON. ISBN: 978-0-660-40601-5

Health Canada. 2021. Di(2-ethylhexyl) phthalate (DEHP) in Canadians. Ottawa, ON. ISBN: 978-0-660-40593-3

Health Canada. 2021. Bisphenol A (BPA) in Canadians. Ottawa, ON. ISBN: 978-0-660-40589-6

Health Canada. 2021. Parabens in Canadians. Ottawa, ON. ISBN: 978-0-660-40599-5

The Maternal Infant Research on Environmental Chemicals (MIREC) Research Platform

In collaboration with : Clinical and academic researchers, and Centre Hospitalier Universitaire Sainte-Justine

Focus of research: The MIREC Research Platform is designed to obtain pan-Canadian data on maternal, fetal, and childhood exposure to priority environmental chemicals and potential adverse health effects on pregnancy, as well as newborn, infant, and childhood growth and development. It encompasses the original MIREC Study of Canadian pregnant women and the follow-up studies of some of their infants (MIREC-Infant Development: MIREC-ID), young children (MIREC-Child Development at age 3: MIREC-CD3, and MIREC- Early Childhood Biomonitoring and Neurodevelopment: MIREC-CD Plus) and adolescents (MIREC - Pubertal Timing, Endocrine and Metabolic Function: MIREC-ENDO). The Platform also includes a repository of MIREC data and biospecimens, the MIREC Biobank, for additional research on the health of mothers and their children.  

Results: In 2021-2022, 10 MIREC Research Platform papers were published, six of which were co-authored by Health Canada. These studies investigated prenatal and lactational exposure to multiple chemicals and nutrients including metals, PFAS, bisphenol A, air pollution, and vitamin D. MIREC researchers published the first pan-Canadian dataset of PFAS in human milk concentrations. Another study addressed a scientific controversy regarding the appropriate analytical method for measuring total urinary BPA. The MIREC Research Platform continues to generate new knowledge on early life cumulative exposure to environmental chemicals and potential health risks in vulnerable populations of pregnant women, fetuses, infants, and children that contributes to risk assessment and management of chemicals both in Canada and internationally.

Publications: Ashley-Martin, J., Gaudreau, É., Dumas, P., Liang, C. L., Logvin, A., Bélanger, P., Provencher, G., Gagne, S., Foster, W., Lanphear, B., Arbuckle, T.E. 2021. Direct LC-MS/MS and indirect GC–MS/MS methods for measuring urinary bisphenol A concentrations are comparable. Environment International, Vol. 157, article number 106874, DOI: 10.1016/j.envint.2021.106874

Fisher, M., Potter, B., Little, J., Oulhote, Y., Weiler, H. A., Fraser, W., Morisset, A.S., Braun, J., Ashley-Martin, J., Borghese, M.M., Shutt, R., Kumarathasan, P., Lanphear, B., Walker, M., Arbuckle, T. E. 2022. Blood metals and vitamin D status in a pregnancy cohort: A bidirectional biomarker analysis. Environmental Research, Vol. 211, article number 113034, DOI: 10.1016/j.envres.2022.113034

Gogna, P., King, W. D., Villeneuve, P. J., Kumarathasan, P., Johnson, M., Lanphear, B., Shutt, R., Arbuckle, T.E., Borghese, M. M. 2021. Ambient air pollution and inflammatory effects in a Canadian pregnancy cohort. Environmental Epidemiology, Vol. 5, Issue 5, p e168, DOI: 10.1097/EE9.0000000000000168

Johnson, M., Shin, H. H., Roberts, E., Sun, L., Fisher, M., Hystad, P., Van Donkelaar, A., Martin, R.V., Fraser, W.D., Lavigne, E., Clark, N., Beaulac, V., Arbuckle, T.E. 2022. Critical Time Windows for Air Pollution Exposure and Birth Weight in a Multicity Canadian Pregnancy Cohort. Epidemiology (Cambridge, Mass.), Vol. 33, Issue 1, pp 7-16, DOI: 10.1097/EDE.0000000000001428

Rawn, D. F., Dufresne, G., Clément, G., Fraser, W. D., & Arbuckle, T. E. 2022. Perfluorinated alkyl substances in Canadian human milk as part of the Maternal-Infant Research on Environmental Chemicals (MIREC) study. Science of The Total Environment, Vol. 831, article number 154888, DOI: 10.1016/j.scitotenv.2022.154888

Weiler, H. A., Brooks, S. P., Sarafin, K., Fisher, M., Massarelli, I., Luong, T. M., Johnson, M., Morisset, A.S., Dodds, L., Taback, S., Helewa, M., von Dadelszen, P., Smith, G., Lanphear, B.P., Fraser, W.D., Arbuckle, T.E. 2021. Early prenatal use of a multivitamin diminishes the risk for inadequate vitamin D status in pregnant women: results from the Maternal-Infant Research on Environmental Chemicals (MIREC) cohort study. The American journal of clinical nutrition, Vol. 114, Issue 3, pp 1238-1250, DOI: 10.1093/ajcn/nqab172

7.1.2.2 Methods

Development of non-targeted methods for use of human biomonitoring data in chemical risk assessment

In collaboration with :

Focus of research: Non-targeted analysis (NTA) encompasses a rapidly evolving set of mass spectrometry techniques aimed at characterizing the chemical composition of complex samples, identifying unknown compounds, and/or classifying samples, without prior knowledge regarding their chemical content. Recent advances in NTA are the result of improved and more accessible instrumentation for data generation and analysis tools for data evaluation and interpretation. As researchers continue to develop NTA approaches in various scientific fields, there is a growing need to identify, disseminate, and adopt community-wide method reporting guidelines. In 2018, NTA researchers formed the Benchmarking and Publications for Non-Targeted Analysis Working Group (BP4NTA) to address this need. Consisting of participants from around the world and representing fields ranging from environmental science and food chemistry to 'omics and toxicology, BP4NTA provides resources addressing a variety of challenges associated with NTA.  This research supports the risk assessment and risk management of chemicals under the Chemicals Management Plan and responds to Health Canada's responsibilities legislated in the Canadian Environmental Protection Act.  The goal of this research is to establish a consensus on NTA-related terms and concepts and to create consistency in reporting practices.

Results: This publication describes the mandate, priorities, and progress of the BP4NTA Working Group. BP4NTA members aim to establish a consensus on NTA-related terms and concepts and to create consistency in reporting practices by providing publicly available web resources, including consensus definitions, reference content, and lists of available tools. Moving forward, BP4NTA will provide a setting for NTA researchers to continue discussing emerging challenges and contribute to additional harmonization efforts. The efforts will allow NTA approaches to be more applicable to screening emerging and unknown chemicals for human exposure assessment. Tools, reporting, and webpages will remain flexible, permitting ongoing updates as NTA techniques evolve and advance.

Publication: Place, B.J., Ulrich, E.M., Challis, J.K., Chao, A., Du, B., Favela, K., Feng, Y.L., Fisher, C.M., Gardinali, P., Hood, A. and Knolhoff, A.M., 2021. An Introduction to the Benchmarking and Publications for Non-Targeted Analysis Working Group. Analytical Chemistry, Vol. 93, issue 49, pp.16289-16296, DOI: 10.1021/acs.analchem.1c02660

Development of novel methods to assess endocrine toxicity of chemical replacements

In collaboration with :

Focus of research: There continues to be a growing concern related to the impact of chemical exposures on the endocrine system. Over the past decades, Canada (under CEPA), and other international governments, have regulated the production and use of chemicals shown to act as endocrine disruptors.  Consequently, this has led to an increased use of alternative chemicals to address market needs. However, toxicity data is limited or not available for many of these replacement chemicals. With a focus on select flame retardants and plasticizers as example chemical classes, the main goals of this multidisciplinary team grant research project project titled “Endocrine Disrupting Chemicals: Towards Responsible Replacements”  are to (1) determine potential for exposure to replacement chemicals, (2) examine the toxicity and potential adverse health effects, and (3) engage with project partners from government, industry, and non-government agencies to discuss safer replacements.

Results: Non-animal methods are used to assess the toxicity of exposure to concentrations of the emerging chemicals found in food and drinking water as detected in human biomonitoring studies. A range of cell lines representing key endocrine functions show that exposure to various replacements result in cell-line and chemical-specific effects on cell viability and phenotypic endpoints. This project contributes to a global effort to reduce animal testing and provides an improved understanding of the potential for toxicity of chemicals that currently lack health effects data. These methods can provide evidence in a screening strategy to identify chemicals with the potential for reproductive and endocrine effects to set priorities for further assessment.

Publications: Rajkumar, A., Luu, T., Beal, M.A., Barton-Maclaren, T.S., Robaire, B., Hales, B.F. 2021. Elucidation of the Effects of Bisphenol A and Structural Analogs on Germ and Steroidogenic Cells Using Single Cell High-Content Imaging. Toxicological Sciences, Vol. 180, Issue 2, pp 224-238, DOI: 10.1093/toxsci/kfab012

Wang, X., Luu, T., Beal, M.A., Barton-Maclaren, T.S., Robaire, B., Hales, B.F. 2022. The Effects of Organophosphate Esters Used as Flame Retardants and Plasticizers on Granulosa, Leydig, and Spermatogonial Cells Analyzed Using High-Content Imaging. Toxicological Sciences, Vol. 186, Issue 2, pp 269-287, DOI: 10.1093/toxsci/kfac012

Rajkumar, A., Luu, T., Beal, M.A., Barton-Maclaren, T.S., Hales, B.F., Robaire, B. 2022. Phthalates and alternative plasticizers differentially affect phenotypic parameters in gonadal somatic and germ cell lines. Biology of Reproduction, Vol. 106, Issue 3, pp 613-627, DOI: 10.1093/biolre/ioab216

Development and application of computational screening methods to predict chemical potency

In collaboration with : Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA

Focus of research: Globally, there are thousands of existing and newly introduced chemicals in commerce with increasing complexity and often with limited toxicity and exposure information. There is a critical need for robust high throughput methods for identifying priorities for chemical risk assessment and risk management. Health Canada continues to increase efforts to advance risk science through the exploration, development and application of computational tools and new approach methodologies (NAMs) to effectively leverage and integrate existing and emerging data. This work explored the use of a novel workflow that applied in silico predictions and read-across methodology to fill key data gaps supporting prioritization of chemicals on the Canadian Domestic Substances List (DSL).

Results: In this project the use of in silico models were explored to address data needs for high throughput toxicokinetics (HTTK) and to predict biological activity of data-poor chemicals on the DSL. Applying the computational approach expanded the number of chemicals that could be screened from an initial 357 chemicals that met the original data requirements for application of the approach to thousands of chemicals. This work demonstrates the power of using NAMs combined with read-across methods allowing for more concentrated focus on testing and assessment efforts of chemicals demonstrating the highest potential for hazard and risk.

Publication: Beal, M.A., Gagne, M., Kulkarni, S.A., Patlewicz, G., Thomas, R.S., Barton-Maclaren, T.S. 2022. Implementing in vitro bioactivity data to modernize priority setting of chemical inventories. ALTEX, Vol. 39, Issue 1, pp 123-139, DOI: 10.14573/altex.2106171

7.1.2.3 Exposure characterization

Characterization of residential exposures - Canadian House Dust Study

Focus of research: The Canadian House Dust Study, a national study involving the collection of dust samples from urban households, provides insight into the presence of chemicals of concern in Canadian households, and the levels to which Canadians are typically exposed. This research supports risk assessment and risk management actions under the Chemicals Management Plan and the Canadian Environmental Protection Act. The goal of this research is to develop and apply methods for the quantification of specific organic compounds (targeted aryl and alkyl-aryl phosphates, which are common in flame retardants and plasticizers) as well as mercury and total carbon content, in Canadian house dust samples.

Results: Study results indicate that some of the target organic compounds were detected in 100% of the samples and detection frequency aligned with concentrations in flame retardant blends used in large quantities in Canada. Strong correlations were found among the three investigated flame retardants, suggesting that consumer and building products containing mixtures of these substances may be present in Canadian homes. Average mercury (Hg) concentrations were found to be higher than average background concentrations reported for outdoor samples, such as soils and sediments. Additionally, investigation of total carbon (TC) identified a correlation between total Hg and TC, reflecting associations previously seen in the outdoor environment. All together, these studies will not only provide household exposure data for Canadians and assist in the development and prioritization of mitigation strategies, but also establish baseline concentrations from the time of sample collection (2007-2010) to support future monitoring of changes and trends. Monitoring could include assessing the impact of industrial or environmental changes and the effectiveness of mitigation. For example, future monitoring of Canadian house dust may provide additional data to identify changing patterns of flame retardant and Hg exposure in Canadian homes.

Publications: Kubwabo C., Fan X., Katuri G.P., Habibagahi A., Rasmussen P.E., 2021. Occurrence of aryl and alkyl-aryl phosphates in Canadian house dust. Emerging Contaminants, Vol. 7, pp. 149-159, DOI: 10.1016/j.emcon.2021.07.002

Levesque, C., Rasmussen, P.E., 2022. Determination of Total Mercury and Carbon in a National Baseline Study of Urban House Dust. Geosciences, Vol. 12, issue 2, art. no. 52, DOI: 10.3390/geosciences12020052

Monitoring of data-poor environmental contaminants in Canadian surface water and sediment

Focus of research: The study focuses on methods of detection and measurement of pesticides and pharmaceuticals in aquatic environments. The information from these measurements is critical to understanding the environmental fate, transport, and occurrence of these substances and assessment of their importance to the health and safety of Canadians and the Canadian environment. Traditional monitoring of environmental contaminants in surface water has consisted of analysis for a set of targeted compounds in discrete samples. The study examined new methods of detection of contaminants in rural, urban, and agricultural areas, using two types of passive chemical samplers, combined with non-targeted analysis. This study was conducted in collaboration with Agriculture and Agri-Food Canada.

Results: Traditional targeted sampling has the limitation of providing only information on compounds within a target list at the time and location of sampling. To try to improve on these methods, which potentially miss episodic events and provide only a ‘snapshot’, two passive samplers were compared, combined with non-targeted analysis (NTA) which detects all ionisable compounds, with the added benefit of data archiving for retrospective mining. Of the two passive samplers compared, polar organic chemicals integrative samplers were found to capture the largest number of analytes with better reproducibility. NTA combined with passive sampling was found to give a more representative picture of the contaminants in mixed-use watersheds representing rural, mixed urban/agricultural, and forested/peri-urban areas. This represents an increase in the amount of chemicals that can be measured, a way to look over a longer term at increases and decreases of a chemical, and the ability to go back and look backwards over previous years at a chemical that is emerging as a new concern.

Publication: Renaud J.B., Sabourin L., Hoogstra S., Helm P., Lapen D.R., Sumarah M.W. 2021 Monitoring of environmental contaminants in mixed‐use watersheds combining targeted and nontargeted analysis with passive sampling. Environmental Toxicology and Chemistry. 2022 May;41(5):1131-43 (Published online 18 August 2021 in Wiley Online Library (wileyonlinelibrary.com), DOI: 10.1002/etc.5192

Influence of conjugation on fate of hormones and pharmaceuticals in Canadian wastewater treatment plants

Focus of research: Pharmaceuticals and hormones may be excreted by humans in conjugated forms, as a result of metabolism. Conjugation is the binding of a small molecule to the larger pharmaceutical or hormone, usually to increase water solubility and make the molecule easier to excrete. Deconjugation (removal of the small molecule) by naturally occurring enzymes in the environment and in wastewater treatment plants (WWTPs) returns the substances to their original form and potency. Detection methods look for only the original free hormone or pharmaceutical and may underestimate the amount, because conjugated forms are not detected. Therefore the level of pharmaceuticals and hormones in municipal WWTPs may be underestimated. The study examined the utility of deconjugating enzymes during screening, to more accurately quantify the occurrence and removal of hormones and pharmaceuticals. This study was conducted in collaboration with Environment and Climate Change Canada.

Results: The study showed that conjugation and deconjugation impact the concentrations and fate of some pharmaceuticals and hormones and their impact varies between analytes and WWTP treatment type. Some pharmaceuticals did not undergo deconjugation in simpler wastewater treatment facilities such as lagoons, and were therefore not removed prior to release, compared to WWTPs which use biological processes in secondary and advanced treatment. Other pharmaceuticals  were shown not to undergo deconjugation and removal in any WWTP, indicating the potential for slow deconjugation and increasing prevalence in the natural environment. The study demonstrated that it is useful to include a deconjugating step during screening of water from WWTPs, because it allows identification of the total (conjugated + deconjugated) form of a pharmaceutical or hormone. The technique was discussed for application to other chemicals excreted by humans in conjugated forms, such as BPA.

Publication: Gewurtz S.B., Teslic S., Hamilton M.C., Smyth S.A., 2022. Influence of Conjugation on the Fate of Pharmaceuticals and Hormones in Canadian Wastewater Treatment Plants. ACS Environmental Science & Toxicology Water. DOI: 10.1021/acsestwater.1c00376

7.1.2.4 Toxicity characterization

Potency ranking of per-and polyfluoroalkyl substances using high-throughput transcriptomic analysis of human liver spheroids

In collaboration with: University of Ottawa and the US National Institutes of Health

Focus of research: Per- and poly-fluoroalkylated substances (PFAS) are a large class of chemicals found in the environment due to their industrial and commercial uses, their persistence, and their high mobility. Exposure to PFAS has been linked to health effects including liver and kidney toxicity. Health Canada compiled a list of 23 PFAS that best represent variability in chemical composition across PFAS and importantly, have been found in Canadian drinking water or could be detected in drinking water. In this study, human liver cells in culture grown as spheroids were exposed to a group of 23 PFAS for shorter (1-day) and longer (10-day) durations and then ranked by potency and hazardous potential using toxicogenomic data. Toxicogenomics is a field of study that investigates how genes respond to chemical exposures, providing information on biological changes related to disease. The aim of the investigation was to use high throughput toxicogenomic methods to identify patterns of potency for various groups of PFAS.

Results: Health Canada found that longer carbon chain length PFAS (7 to 10 carbons) were more potent than shorter-chain length PFAS (fewer than 6 carbons).  Specific PFAS had a greater likelihood of inducing biological changes at lower exposure levels, and the 23 PFAS studied could be ranked by their potency. This study improves  understanding of the health effects of PFAS and demonstrates the potential for toxicogenomic techniques as an alternative to more traditional toxicological methodologies using animals. These techniques are examples of New Approach Methodologies (NAMs), which are essential in moving beyond traditional animal testing methods.  Acquiring information on data poor substances for risk assessment has been challenging for regulatory agencies worldwide, including Health Canada, and these NAMs may be an important tool for generating data for future risk assessment activities with respect to PFAS, and other chemical classes.

Publication: Reardon, A. J., Rowan-Carroll, A., Ferguson, S. S., Leingartner, K., Gagne, R., Kuo, B., Williams, A., Lorusso, L., Bourdon-Lacombe, J.A., Carrier, R., Moffat, I., Yauk, C.L., Atlas, E. 2021. Potency ranking of per-and polyfluoroalkyl substances using high-throughput transcriptomic analysis of human liver spheroids. Toxicological Sciences, Vol. 184, issue 1, pp 154-169, DOI: 10.1093/toxsci/kfab102

7.1.2.5 Nanomaterials and microplastics

Low dose antibiotic ingestion potentiates systemic and microbiome changes induced by silver nanoparticles

In collaboration with: Environment and Climate Change Canada and McMaster University

Focus of research: Health Canada is responsible for regulating applications and products containing nanoparticles (NPs) to protect the health of Canadians. In order to provide scientific evidence towards human health risk assessments of NPs, research at Health Canada is aimed at understanding the behaviour and effects of NPs on human health in various exposure scenarios. Health Canada studied NPs composed of silver, which are added as antibiotics in several different consumer products such as bandages, food packaging, and sports clothing.  Existing scientific evidence for the health hazard associated with silver NPs is conflicting, but evidence from exposure to other antibiotics provides a strong rationale to assess silver NP effects on organ function, immunity, metabolism, and gut-associated microbiota. The aim of this study was to investigate systemic toxicity of silver NPs, including toxic effects on the microbiome.

Results: Mice were exposed to silver NPs for 5 weeks by ingestion, with and without low doses of conventional antibiotics. Animals were weighed daily, assessed for glucose tolerance, organ function, tissue and blood immunological markers, and changes in the gut microbiome. The data demonstrated animal weight loss and systemic immunological effects which corresponded with alterations in the gut microflora. Gut microbiota changes were more sensitive indicators of toxicity compared to metabolic or immunological markers. Furthermore, the study identified alterations in the presence of specific types of microbes associated with immunological balance. This study supports the notion that key microbial species in the gut may serve as sensitive indicators of chemical-induced stress, even at doses that may not elicit a systemic response. The results will support development of novel toxicological endpoints that can be used for risk assessment of nanomaterials.

Publication: Meier M.J., Nguyen K.C., Crosthwait J, Kawata A., Rigden M. ,Leingartner K., Wong A., Holloway A., Shwed P.S., Beaudette L., Navarro M., Wade M., Tayabali A.F. 2021. Low dose antibiotic ingestion potentiates systemic and microbiome changes induced by silver nanoparticles. NanoImpact, Vol. 23, article number 100343, DOI: 10.1016/j.impact.2021.100343

Adverse Outcome Pathways to identify, prioritize and develop mechanisms-informed experimental test systems and targeted toxicity assays for nanomaterials and microplastics safety assessment

Focus of research: Nanomaterials (NM) are man-made substances in the size range of 1-100 nanometers with unique properties widely used in various commercial applications. According to animal-based research results, the size-associated properties of some NMs contribute to their toxicity. Microplastics (MP) are small fragments, fibres or particles generated from weathering of plastics in the environment. MPs share many properties with NMs and could also pose a health hazard. Animal testing is not a feasible option for NMs or MPs because of the time and resource intensiveness of toxicity testing methods, the considerable number of particles and the diversity of particle properties to be assessed.

Adverse Outcome Pathway (AOP), and AOP-informed mechanism-based approaches are under development as alternatives to animal testing for NM and MP safety assessment. AOPs enable the systematic organization of complex information about mechanisms that eventually lead to toxic effects through simple linear sequences of key biological events at the cellular, tissue and individual or population levels. AOPs allow the design and development of targeted strategies as alternatives to animal testing.

Results: Through a systematic literature review a NM database and a method for identification of Key Events (KEs) from the NM literature were developed. KEs are biological events induced by NMs, related to mechanisms of NM-induced toxicity. Several KEs that can be targeted by readily available, specific, and non-animal, assays were identified. Furthermore, five AOPs related to lung toxicity due to NM inhalation are under development. Moreover, NM literature was used to propose an AOP and to prioritize and develop mechanism-informed experimental test systems and targeted toxicity assays for the safety assessment of MPs. Lastly, the opportunities, challenges, and considerations for assessing NM and MP toxicity were highlighted.

Publications: Halappanavar, S., Mallach, G. 2021. Adverse outcome pathways and in vitro toxicology strategies for microplastics hazard testing. Current Opinion in Toxicology, Vol. 28, pp 52-61, DOI: 10.1016/j.cotox.2021.09.002

Rahman, L., Mallach, G., Kulka, R., Halappanavar, S. 2022. Microplastics and nanoplastics science: collecting and characterizing airborne microplastics in fine particulate matter. Nanotoxicology, Vol. 15, Issue 9, pp 1253-1278, DOI: 10.1080/17435390.2021.2018065

7.2 Air pollutants and greenhouse gases

Air quality research

7.2.1 Environment and Climate Change Canada Research

Ongoing research continued on a wide range of air pollutants, including short-lived climate pollutants, ammonia, nitrogen oxides (NOx), sulphur dioxide (SO2), volatile organic compounds (VOCs), ozone, and particulate matter/aerosols. A sample of the research papers on the topics of air pollutants and GHGs published in peer-reviewed scientific journals in 2021-2022 is referenced below.

Long term trends and characteristics of airborne particulate matter in Canadian urban areas

Focus of research: Trends in the amounts and types of carbon contained in atmospheric fine particulate matter (PM2.5) were analyzed using National Air Pollution Surveillance (NAPS) network data from seven Canadian cities over the period 2003-2017.  The characteristics and sources of trace elements in PM2.5, and PM10-2.5 (coarse particulate matter), were investigated in dense traffic areas in Toronto and Vancouver, from 2015–2017.

Results: Analysis showed only a modest decline in concentrations of organic carbon, but a significant decrease in the concentration of elemental carbon, which is associated with combustion processes such as biomass burning and fossil fuel combustion, especially from diesel engines.  Declining use of firewood for fuel and more stringent emissions standards and regulations in the transportation sector were identified as causes of this decline.

Overall, the results of the study of PM near urban roadways show that non-exhaust traffic-related processes (crustal/road dust, brake/tire wear) were major contributors to the various metal species in PM that are prone to form reactive oxidation products that may negatively affect human health.

Publications: Wang, H., Zhang, L., Yao, X., Cheng, I., Dabek-Zlotorzynska, E. Identification of decadal trends and associated causes for organic and elemental carbon in PM2.5 at Canadian urban sites, Environment International, 159, art. no. 107031, DOI:10.1016/j.envint.2021.107031, 2021

Celo, V., Yassine, M.M., Dabek-Zlotorzynska, E.: Insights into Elemental Composition and Sources of Fine and Coarse Particulate Matter in Dense Traffic Areas in Toronto and Vancouver, Canada, Toxics, 9 (10), Art. No. 264, DOI:10.3390/toxics9100264, 2021

Effects of Tier 3 fuel on motorcycle emissions

Focus of research: Tests were conducted on three motorcycles produced for the North American market to compare the impacts on emissions of using Tier 3 fuel containing 10% ethanol (E10) versus Tier 2 fuel without ethanol (E0).

Results: Generally, the tests showed that using E10 fuels compared with E0 fuels resulted in reduced emissions of carbon monoxide, carbon dioxide, hydrocarbons and some air toxics such as toluene and benzene; the potential to form ozone was also reduced.  There was no trend found regarding emissions of particulate matter, and some pollutant emissions increased (NOx, acetaldehyde). The study provides insights on the emission inventory impacts from the introduction of ethanol-containing fuels.

Publication: Rosenblatt, D., Stokes, J., Caffrey, C., Brown, K.: Effect of North American Certification Test Fuels on Emissions from On-Road Motorcycles, SAE Technical Papers, DOI:10.4271/2021-01-1225

Effects on air quality of the COVID-19 pandemic and lockdowns

Focus of research: Studying the effects of reduced emissions on key air pollutants in Canada and globally due to the COVID-19 pandemic and lockdowns.

Results: Countries with strict lockdown conditions had average NO2 concentrations 29% lower than countries without.  Global and Canadian studies showed large reductions in NO2 linked to the decline of vehicle traffic, whereas pollutants such as CO2 and fine particulate matter showed lesser reductions or did not have a clear change.

Publications: Sokhi, R.S., Singh, V., Querol, X., Finardi, S., Targino, A.C., Andrade, M.D.F., Pavlovic, R., Garland, R.M., Massagué, J., Kong, S., Baklanov, A., Ren, L., Tarasova, O., Carmichael, G., Peuch, V.-H., Anand, V., Arbilla, G., Badali, K., Beig, G., Belalcazar, L.C., Bolignano, A., Brimblecombe, P., Camacho, P., Casallas, A., Charland, J.-P., Choi, J., Chourdakis, E., Coll, I., Collins, M., Cyrys, J., da Silva, C.M., Di Giosa, A.D., Di Leo, A., Ferro, C., Gavidia-Calderon, M., Gayen, A., Ginzburg, A., Godefroy, F., Gonzalez, Y.A., Guevara-Luna, M., Haque, S.M., Havenga, H., Herod, D., Hõrrak, U., Hussein, T., Ibarra, S., Jaimes, M., Kaasik, M., Khaiwal, R., Kim, J., Kousa, A., Kukkonen, J., Kulmala, M., Kuula, J., La Violette, N., Lanzani, G., Liu, X., MacDougall, S., Manseau, P.M., Marchegiani, G., McDonald, B., Mishra, S.V., Molina, L.T., Mooibroek, D., Mor, S., Moussiopoulos, N., Murena, F., Niemi, J.V., Noe, S., Nogueira, T., Norman, M., Pérez-Camaño, J.L., Petäjä, T., Piketh, S., Rathod, A., Reid, K., Retama, A., Rivera, O., Rojas, N.Y., Rojas-Quincho, J.P., San José, R., Sánchez, O., Seguel, R.J., Sillanpää, S., Su, Y., Tapper, N., Terrazas, A., Timonen, H., Toscano, D., Tsegas, G., Velders, G.J.M., Vlachokostas, C., von Schneidemesser, E., VPM, R., Yadav, R., Zalakeviciute, R., Zavala, M.: A global observational analysis to understand changes in air quality during exceptionally low anthropogenic emission conditions, Environment International, 157, 106818 (2021), DOI: 10.1016/j.envint.2021.106818

Mashayekhi, R., Pavlovic, R., Racine, J., Moran, M.D., Manseau, P.M., Duhamel, A., Katal, A., Miville, J., Niemi, D., Peng, S.J., Sassi, M., Griffin, D., McLinden, C.A. Isolating the impact of COVID-19 lockdown measures on urban air quality in Canada (2021) Air Quality, Atmosphere and Health, DOI: 10.1007/s11869-021-01039-1

You Y, Byrne B, Colebatch O, Mittermeier RL, Vogel F, Strong K. Quantifying the Impact of the COVID-19 Pandemic Restrictions on CO, CO2, and CH4 in Downtown Toronto Using Open-Path Fourier Transform Spectroscopy, Atmosphere, 12(7), 848 (2021), DOI: 10.3390/atmos12070848

Zhao, X., Fioletov, V., Alwarda, R., Su, Y., Griffin, D., Weaver, D., Strong, K., Cede, A., Hanisco, T., Tiefengraber, M., McLinden, C., Eskes, H., Davies, J., Ogyu, A., Sit, R., Abboud, I., Lee, S.C.: Tropospheric and Surface Nitrogen Dioxide Changes in the Greater Toronto Area during the First Two Years of the COVID‐19 Pandemic, Remote Sens. 2022, 14(7), 1625, DOI: 10.3390/rs14071625

Atmospheric emissions from wildfires and other biomass burning

Focus of research: Evaluating the influence of forest-fire emissions on the accuracy of weather and air quality forecasts, and measuring gaseous mercury emissions in plumes of forest wildfires.

Results: It was determined that emissions plumes create feedback loops which affect local weather and the behaviour of the plumes themselves. Incorporating these effects can significantly improve forecast accuracy.

Aircraft-based measurements of gaseous mercury in the smoke plume downwind of a forest fire in northern Saskatchewan were used to estimate the concentrations of mercury at the source. Comparison with existing estimation methods indicates that the assumptions used in those methods create extremely high uncertainty of the results, making it difficult to extrapolate these results to all forest fires.

Publications: Makar, P. A., Akingunola, A., Chen, J., Pabla, B., Gong, W., Stroud, C., Sioris, C., Anderson, K., Cheung, P., Zhang, J., and Milbrandt, J. Forest-fire aerosol–weather feedbacks over western North America using a high-resolution, online coupled air-quality model, Atmos. Chem. Phys., 21, 10557–10587 (2021), DOI: 10.5194/acp-21-10557-2021

McLagan, D. S., Stupple, G. W., Darlington, A., Hayden, K., and Steffen, A. Where there is smoke there is mercury: Assessing boreal forest fire mercury emissions using aircraft and highlighting uncertainties associated with upscaling emissions estimates, Atmos. Chem. Phys., 21, 5635–5653 (2021), DOI: 10.5194/acp-21-5635-2021, 2021

Sources and deposition of air emissions from the Alberta oil sands

Focus of research: Atmospheric emissions, including sources, atmospheric lifetimes, and deposition in and downwind of the oil sands region (OSR), and the estimation of fugitive emissions of pollutants, including volatile organic compounds (VOCs), from tailings ponds.

Results: Oil sands-related sources are regional contributors to nearly all air pollutants. Most pollutants exhibit enhanced air concentrations within approximately 20 km of surface-mining activities, with some enhanced concentrations greater than 100 km downwind. Oil sands industries were a key source. 

The transport distances and lifetimes of SOx and NOx emitted from oil sands operations were substantially shorter than air quality models predicted, suggesting greater deposition of these pollutants close to their sources and less deposition further away than previously thought. 

Field measurements indicated that, in 2017, one tailings pond emitted between 2600 and 4000 tons of VOCs, approximately double the quantity reported using currently accepted estimation methods.  Further analysis indicated that these emissions contributed up to 57% of the total VOCs measured at the nearby community of Fort McKay, reinforcing the importance of accurate VOC emission estimation methods for tailings ponds.

Publications: Horb, E.C., Wentworth, G.R., Makar, P.A., Liggio, J., Hayden, K., Boutzis, E.I., Beausoleil, D.L., Hazewinkel, R.O., Mahaffey, A.C., Sayanda, D., Wyatt, F., Dubé, M.G. A decadal synthesis of atmospheric emissions, ambient air quality, and deposition in the oil sands region, Integrated Environmental Assessment and Management, DOI: 10.1002/ieam.4539, 2021

Mamun, A.A., Celo, V., Dabek-Zlotorzynska, E., Charland, J.-P., Cheng, I., Zhang, L. Characterization and source apportionment of airborne particulate elements in the Athabasca oil sands region (2021) Science of the Total Environment, 788, art. no. 147748, DOI: 10.1016/j.scitotenv.2021.147748

Hayden, K., Li, S.-M., Makar, P., Liggio, J., Moussa, S. G., Akingunola, A., McLaren, R., Staebler, R. M., Darlington, A., O'Brien, J., Zhang, J., Wolde, M., and Zhang, L.: New methodology shows short atmospheric lifetimes of oxidized sulfur and nitrogen due to dry deposition, Atmos. Chem. Phys., 21, 8377–8392, DOI:10.5194/acp-21-8377-2021, 2021

Moussa, S.G., Staebler, R.M., You, Y., Leithead, A., Yousif, M.A., Brickell, P., Beck, J., Jiang, Z., Liggio, J., Li, S.-M., Wren, S.N., Brook, J.R., Darlington, A., Cober, S.G.: Fugitive Emissions of Volatile Organic Compounds from a Tailings Pond in the Oil Sands Region of Alberta, Environ. Sci. Technol., 55, 19, 12831–12840, DOI:10.1021/acs.est.1c02325, 2021

7.2.2 Health Canada research

In 2021-2022, HC continued to research the health impacts of human exposure to indoor and outdoor air pollutants in order to provide guidance to governments, industries, other organizations and individuals on how to address air pollution. HC scientists published 38 articles in peer reviewed scientific journals. These publications addressed issues such as:

7.2.2.1 Role of stress in health effects of air pollutants

The role of stress and stress reactivity in mediating impacts of air pollutants on the brain and lungs

Focus of research: Previous studies have shown that exposure to ambient air pollution in Canada is associated with increased risk of neurological and mental health disorders (e.g. cognitive decline, dementia, depression). While the underlying mechanisms are unclear, stress may be a central unifying mechanism underlying health impacts and susceptibility. This project focuses on how the local and systemic stress responses initiated following pollutant exposure contribute to effects on health, with particular attention on brain and lungs. More specifically, the objective of this research is to investigate the role of stress responses in mediating impacts of pollutant inhalation using in vivo and in vitro models, examining the biological pathways that underlie the health effects of air pollution.

Results: HC showed that exposure to ozone, a highly reactive air pollutant, increases stress hormone levels in the lungs. These stress hormone levels were shown to control the responses to ozone of immune cells in the lungs. Differences in the inflammation response between high and low stress responsive subgroups suggests that individual differences in stress response may be important in determining effects of exposure to air pollutants. Inhalation of particulate air pollution was shown to impact markers of key central nervous system (CNS) stress pathways, blood pressure, and heart rate variability. These research results suggest stress hormones are a key part of the body’s response to air pollutants and highlight how individual differences in health and genes may contribute to vulnerability. Health Canada has also successfully established a system for assessing exposure of lung cells to gases and particulates, an important step in enabling assessment of effects of air pollutants in human cells using more physiologically-relevant exposure models. Future research will expand understanding of the mechanisms of air pollutants and stress in cell models alongside epidemiological studies in the Canadian context.

Publications: Thomas, J., Stalker, A., Breznan, D., Thomson, E.M. 2021. Ozone-dependent increases in lung glucocorticoids and macrophage response: Effect modification by innate stress axis function. Environmental Toxicology and Pharmacology. Vol. 86, DOI: 10.1016/j.etap.2021.103662

Thomas, J., Thomson, E.M., 2021 Modulation by ozone of glucocorticoid-regulating factors in the lungs in relation to stress axis reactivity. Toxics. Vol 9, Issue 11, article number 290, DOI: 10.3390/toxics9110290

Thomson, E.M., 2021. Air pollution, stress, and allostatic load: Linking systemic and central nervous system impacts in Alzheimer's Disease and Air Pollution: The Development and Progression of a Fatal Disease from Childhood and the Opportunities for Early Prevention. pp 387-404, DOI: 10.3233/AIAD210032

Vincent, R., Kumarathasan, P, Goegan, P., Bjarnason, S.G., Guénette, J., Karthikeyan, S., Thomson, E.M., Adamson, I.Y., Watkinson, W.P., Battistini, B., Miller, F.J., 2022. Acute cardiovascular effects of inhaled ambient particulate matter: Chemical composition-related oxidative stress, endothelin-1, blood pressure, and ST-segment changes in Wistar rats. Chemosphere, Vol. 296, DOI: 10.1016/j.chemosphere.2022.133933

7.2.2.2 Air pollution and COVID-19

Impacts of exposure to air pollution on COVID-19

In collaboration with: Hospitals and Universities in Canada and Chile

Focus of research: Many studies have shown that ambient air pollution is associated with a wide range of adverse health effects, including increased risk of respiratory infection. Studies from the United States and Europe suggest that both short and long-term exposure to air pollution may increase the incidence of, and mortality from, COVID-19, a primarily respiratory illness. As COVID-19 is currently at the forefront of public health, existing collaborations including a collaboration in Chile, were leveraged to enhance understanding of the impacts of COVID and air pollution on the health of Canadians. This research investigates the links between ambient air pollution and COVID-19 in Alberta and Ontario, Canada, and in Santiago, Chile.

Results: Short-term increases in ambient air pollution in Santiago, Chile were associated with increased mortality, suggesting that acute increases in air pollution may be a risk factor for daily COVID-19 mortality. In Alberta and Ontario, Health Canada found links between short-term exposure to ambient air pollutants and COVID-19 emergency department visits, suggesting that exposure to air pollution may also lead to more severe COVID-19 disease. Health Canada has also investigated the mechanisms that might link air pollution to COVID-19 infection, such as oxidative stress. Interestingly, in 140 Toronto neighbourhoods, the number of cases of COVID-19 infection was linked to the potential for fine particulate matter (PM2.5) to cause oxidative stress. Adjusting for other factors, neighbourhoods with higher levels of oxidative stress from PM2.5 had a larger number of COVID-19 cases. This suggests that reducing oxidative stress from air pollution could reduce the incidence of COVID-19. Taken together these results suggest that air pollution may play a role in rates of COVID-19 infection and the severity of COVID-19 disease. More research is needed to confirm these findings, and additional studies are ongoing.

Publications: Dales, R., Blanco-Vidal, C., Romero-Meza, R., Schoen, S., Lukina, A., Cakmak, S., 2021. The association between air pollution and COVID-19 related mortality in Santiago, Chile: A daily time series analysis. Environmental Research. Vol 198, number 111284, DOI: 10.1016/j.envres.2021.111284

Lavigne, E., Ryti, N., Gasparrini, A., Sera, F., Weichenthal, S., Chen, H., To, T., Evans, G.J., Sun, L., Dheri, A., Lemogo, L., Kotchi, S.O., Stieb, D., 2022. Short-term exposure to ambient air pollution and individual emergency department visits for COVID-19: a case-crossover study in Canada. Thorax, number 2021-217602, DOI:10.1136/thoraxjnl-2021-217602

Stieb, D.M., Evans, G.J., To, T.M., Lakey, P.S.J., Shiraiwa, M., Hatzopoulou, M., Minet, L., Brook, J.R., Burnett, R.T., Weichenthal, S.A., 2021. Within-City Variation in Reactive Oxygen Species from Fine Particle Air Pollution and COVID-19. American Journal of Respiratory Critical Care Medicine. Vol. 204 Issue 2, pp 168-177, DOI: 10.1164/rccm.202011-4142OC [epub 2 Apr 2021]

Stieb, D.M., 2022. Strengthening the Epidemiological Evidence Linking Air Pollution and COVID-19. American Journal of Respiratory Critical Care Medicine. Vol 205, Issue 6, pp 605-606, DOI: 10.1164/rccm.202112-2813ED [epub 15 Mar 2022]

7.2.2.3 Associations between air pollution and health outcomes

Chronic disease and air pollution: disease trajectory & intervention

In collaboration with: Statistics Canada, Environment and Climate Change Canada, ICES, and Canadian and International Universities

Focus of research: Air pollution has major public health and economic consequences. Health Canada is comprehensively investigating the role of chronic exposure to air pollution (months to years) in affecting individuals’ trajectories over different health states (e.g. heart and vascular diseases), and how this unfolds along different physiological pathways. Considering the preponderance of evidence of the health effects of air pollution, the first objective of the project is to move beyond the question "does air pollution affect health?", to the question "how does air pollution affect health?". The second objective is to further evaluate the effectiveness of some widely implemented or potential individual- and policy-level interventions in reducing air health effects, as considerable uncertainty exists concerning which actions can be taken to reduce air pollution effects.

Results: This project draws on the Canadian Census Health and Environment Cohort (CanCHEC), and takes advantage of novel scientific approaches, including causal inference methodologies and quasi experimental designs. Key results include consistent association between long-term exposure to ambient air pollution and myocardial infarction and stroke hospitalization in the CanCHEC cohort. Furthermore, members of the CanCHEC cohort who moved from areas of lower particulate air pollution to areas of higher air pollution showed a significant increase in mortality when compared to those who moved between areas that had similar air pollution. Correspondingly, moving from areas of higher particulate air pollution to areas of lower pollution was associated with reduced mortality.

This information provides important data to support evidence-based health guidance. Future studies will investigate the impacts of interventions that reduce air pollution, as well as for estimating the burden of exposure on various aspects of the disease trajectory.

Publications: Chen H, Kaufman JS, Olaniyan T, Pinault L, Tjepkema M, Chen L, van Donkelaar A, Martin RV, Hystad P, Chen C, Kirby-McGregor M, Bai L, Burnett RT, Benmarhnia T. Changes in exposure to ambient fine particulate matter after relocating and long term survival in Canada: quasi-experimental study. The British Medical Journal. Vol. 375, number 2368, DOI: 10.1136/bmj.n2368

Olaniyan, T., Pinault, L., Li, C., van Donkelaar, A., Meng, J., Martin, R.V., Hystad, P., Robichaud, A., Ménard, R., Tjepkema, M., Bai, L., Kwong, J.C., Lavigne, E., Burnett, R.T., Chen, H., 2021. Ambient air pollution and the risk of acute myocardial infarction and stroke: A national cohort study. Environmental Research. Vol. 204, Pt A, number 111975, DOI: 10.1016/j.envres.2021.111975

7.2.2.4 Indoor air pollution and health

Sioux Lookout Zone: Children's Health Study

In collaboration with: Children's Hospital of Eastern Ontario; University of Ottawa; Northern Ontario School of Medicine; Nishnawbe Aski Nation; Energy Matters; Carleton University; Sioux Lookout First Nations Health Authority; Sioux Lookout Meno Ya Win Health Centre; Carleton University

Focus of research: According to the Canadian Paediatric Society, housing directly affects the health of children and youth. First Nations and Inuit are disproportionately affected by crowded and inadequate housing, which has been associated with increased hospital admissions of children for respiratory tract illnesses. It has been shown that Aboriginal children in communities in the Sioux Lookout Zone (Sioux Lookout First Nations Health Authority; SLZ) in northern Ontario have elevated rates of asthma, bronchiolitis and pneumonia, but there is little information on their indoor environmental quality. This study aimed to evaluate Indoor Environmental Quality (IEQ) in houses of 98 children living in four isolated communities in this area in relation to respiratory health and related utilisation of health care services.

Results: This study showed that much of the housing in the Sioux Lookout Zone area is in poor condition and that the children have high rates of respiratory infections, medical evacuations and dermatological conditions requiring treatment. Indoor endotoxin load was extremely high, and associated with LRTI, hospitalization for chest illnesses early in life, and wheezing with colds. Upper respiratory infections were associated with increased exposure to mold indoors.

Publication: Kovesi, T., Mallach, G., Schreiber, Y., McKay, M., Lawlor, G., Barrowman, N., Tsampalieros, A., Kulka, R., Root, A., Kelly, L., Kirlew, M., Miller, J. D. (2022). Housing conditions and respiratory morbidity in Indigenous children in remote communities in Northwestern Ontario, Canada. 194(3), E80–E88. DOI: 10.1503/cmaj.202465

7.2.2.5 Air pollution from transportation sources

Canadian Atlantic Marine Air Pollution Study

In collaboration with: Environment and Climate Change Canada, Ontario Ministry of Environment, Conservation and Parks, University of Rochester and Dalhousie University

Focus of research: To address marine shipping air pollution, Canada and the United States jointly implemented a North American Emissions Control Area (NA ECA) within which ships are regulated to use lower-sulphur marine fuel or equivalent sulphur dioxide (SO2) scrubbers (i.e., 3.5% maximum fuel sulphur reduced to 1% sulphur in 2012 and 0.1% in 2015).  To investigate the effects of these regulations on local air quality, air pollutant concentrations (including SO₂, PM2.5, NO₂, O₃ and related PM2.5 components) were examined between 2010 –2016 at the Canadian port cities of Halifax, Vancouver, Victoria, Montreal and Quebec City.

Results: Study results indicate that the implementation of the NA ECA improved air quality at Canadian port cities immediately following the requirement for lower-sulphur fuel. Specifically, SO₂ concentrations showed large decreases at all sites, with the largest improvements in the coastal cities when the 0.1% fuel sulphur regulation took effect. Residual fuel oil marker species vanadium (V) and Nickel (Ni) in PM2.5 dramatically declined following regulation implementation. This is consistent with decreased residual fuel oil use and suggestive of a switch to low-sulphur distillate fuel oil. Smaller reductions in PM2.5 were also observed, reflecting the importance of non-marine PM sources.

Publication: Anastasopolos, A.,  Sofowote, U., Hopke, P., Rouleau, M., Shin, T., Dheri, A., Peng, H., Kulka, R., Gibson, M., Farah, P-M., Sundar, N. Air quality in Canadian port cities after regulation of low-sulfur marine fuel in the North American Emissions Control Area. The Science of the Total Environment, Vol. 791, 147949, pp 1-12, DOI:10.1016/j.scitotenv.2021.147949

7.2.2.6 Toxicity of air pollution

Full list of publications included in Annex.

7.2.2.7 Global health and economic impacts of particulate matter

Full list of publications included in Annex.

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