Canadian Environmental Protection Act annual report 2018 to 2019: chapter 6

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6. Report on research

6.1 Chemical substances

Environment and Climate Change Canada (ECCC) and Health Canada (HC) conduct a wide range of research to help inform assessments of the risks associated with various substances to human health or the environment. This research is designed primarily:

In addition, HC undertakes research to support the development of regulations, guidelines and air quality objectives with the goal of reducing population exposures to pollutants and improving human health.

During 2018-2019, 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 Program, Genome Canada and the Great Lakes Action Plan.

ECCC research

The 20 research projects initiated at ECCC under the CMP in 2016 were completed in 2018-2019. These projects, summarized below, have led to the publication of 39 journal articles in 2018-2019 addressing a range of topics related to environmental contaminants, including sources, fate, mode of action, hazard, as well as standard methods development.

Rare earth elements (REEs) and platinum group elements (PGEs)
Study of REEs and PGEs on aquatic and terrestrial biota (crops, native plants and invertebrates): implications for ecological risk assessment at contaminated sites

Focus of research: The effects of soil pH and calcium content on the uptake, accumulation, and toxicity of various REEs, both individually and in mixtures, was examined for terrestrial plants. In addition, the study looked at the impacts of various REEs on aquatic plants and invertebrates. As well, this project examined the effects of PGEs on the physiology of terrestrial plants, with focus on both indicators of water stress and pollen viability and health.

Results: Plant biomass was generally significantly affected by soil pH and REE dose. A significant interaction between soil pH and REE sensitivity was occasionally detected. In low pH soils, the biomass of the plant parts was significantly enhanced with the addition of calcium while in the high pH soils biomass was reduced with higher calcium levels. Many interactions between REE concentrations, calcium, and pH were significant. Some interactions between water stress and PGE dose were present, however, no consistent trend was determined. Cerium was observed to negatively affect pollen germination in all plant species analyzed. Embryos contaminated with REEs had a negative effect on hatching time and success.

Publications: The results of this research were summarized in an internal technical report.

Effect of 4 rare earth element lanthanides in boreal forest soil on invertebrates and soil microbial community

Focus of research: The toxicity of four lanthanide REEs on invertebrate species and indigenous microorganisms in Canadian boreal forest soil were evaluated. The impact of aging on the toxicity of 2 lanthanide REEs was also analysed.

Results: Among other findings, this project provided toxicity thresholds for the REEs, praseodymium, samarium, neodymium, and yttrium for risk assessment analysis. Results showed that there was no consistent toxicity impact from the aging of the test substances in soil.

Publications: Princz, J.I., Fraser, C., Lemieux, H., Boyd, P., Scroggins, R. 2019. The effect of aging on toxicity of lanthanides to soil invertebrates in boreal soils. (In preparation)

Aquatic ecotoxicology of lanthanides

Focus of research: The toxicity of priority REEs and mixtures was examined in fish and bivalves and determined their mode of action. The molecular toxicology of certain REEs was analysed to ascertain whether there were similarities and if toxicity could be predicted based on atomic properties.

Results: The toxicity of rare earth chemical elements depends on the type of elements and species under study. For fish, the chemical elements yttrium, samarium, erbium and gadolinium, were considered the most toxic. Providing more details about the effects, the biomarker analysis revealed impacts on protein integrity - essential for organisms health, DNA damage natural repair capacity, and physiological malfunctioning (some enzymes related activity). The studied organisms (mussels and the cnidarian Hydra) revealed similar toxicity effects as fish, although the Hydra species proved to be the most sensitive species compared with others.

Publications: Dubé, M., Auclair J., Hanana, H., Turcotte, P., Gagnon, C., Gagné, F. 2019. Gene expression changes and toxicity of selected rare earth elements in rainbow trout juveniles. Comp Biochem Physiol C Toxicol Pharmacol. 2019 Sep;223:88-95

Hanana, H; Turcotte, P; Dubé, M; Gagnon, C; Gagné, F. 2018. Response of the freshwater mussel, Dreissena polymorpha to sub-lethal concentrations of samarium and yttrium after chronic exposure. Ecotoxicol Environ Saf. 2018 Dec 15;165:662-670

Blaise, C; Gagné, F; Harwood, M; Quinn, B; Hanana, H. 2018. Ecotoxicity responses of the freshwater cnidarian Hydra attenuata to 11 rare earth elements. Ecotoxicol Environ Saf. 2018 Nov 15; 163:486-491

Organic flame retardants, benzotriazole, benzothiazole and other priority substances
Evaluation of estrogenic and thyroid-disrupting activities of targeted CMP3 priority substances: benzotriazole, thiocarbamate, hindered phenols and a brominated organophosphate flame retardant

Focus of research: The study evaluated the impact of these substances on the hormone processes involved in the metamorphosis of tadpoles to frogs. These substances were assessed for their effects on time to metamorphosis, growth, gender, expression of genes involved in development and sexual differentiation, and histology of thyroid and gonadal tissue.

Results: Chronic exposures to the tested hindered phenol (CAS 96-76-4), benzotriazole (CAS 3147759) and the brominated organophosphate flame retardant (CAS 19186-97-1) did not affect the hormone processes of Lithobates pipiens tadpoles. Tested hindered phenols with CAS 96-69-5 and CAS 61788-44-1 were highly toxic at all concentrations tested for Lithobates pipiens tadpoles exposed.

Publications: This project permitted the preparation and publication of several articles, amongst which was a publication on the toxicity of various solvents on native amphibians early life stages.

Using a multi-tiered screening approach and the adverse outcome pathway (AOP) framework to determine the effects of new and existing priority CMP3 substances, primarily organic flame retardants, on key neuroendocrine pathways

Focus of research: Since there is an urgent need for novel testing approaches that can help overcome some of the acknowledged limitations and cost of traditional ecological risk assessment, 10 organic flame retardants and five Bisphenol A (BPA) alternatives were analyzed for their toxicity to birds with both novel and regular in vitro screening methods. ToxChip polymerase chain reaction (PCR) arrays were used to determine the transcriptomic responses of the CMP3 substances. Chemicals which elicited a strong response were tested by in ovo egg injection method to determine the adverse effects of mechanistic exposure at an organismal level.

Results: Among other things, results showed that two organic flame retardants elicited negative effects on cell viability, and all five BPA alternative substances tested decreased cell viability. In addition, the research resulted in the development of a novel cell-culture method to allow screening in wild avian species.

Publications: Basu, N., Crump, D., Head, J., Hickey, G., Hogan, N., Maguire, S., Xia, J., Hecker, M. 2019. EcoToxChip - A Next-Generation Toxicogenomics Tool for Chemical Prioritization and Environmental Management. Environ. Toxicol. Chem. 38(2): 279-288. DOI: 10.1002/etc.4309

Environmental transformation processes and bioaccumulation, fate and effects of CMP3 priority organic flame retardants (OFRs) in wildlife and fish within an AOP framework

Focus of research: This study addressed the limited understanding of CMP3 priority OFRs and the role of degradation, metabolism and transformation in wildlife and fish. The project assisted with the challenges and concerns for scientists, risk assessors, and managers as to OFR sources, bioavailability and ecosystem behaviour and ultimately their potential toxicology and health impacts on exposed biota.

Results: This allowed the characterization of the fate and metabolism of these CMP3 priority OFRs in avian species at multiple biological scales, feeding into an Avian AOP Framework.

Publications: Zhang, Y., Su, G. G., Li, M., Li, S., Wang, Q., Zhu, G., Letcher, R.J., Liu, C. 2018. Chemical and biological transfer: Which one is responsible for the maternal transfer toxicity of tris(1,3-dichloro-2-propyl) phosphate in zebrafish? Environ. Pollut. 243:1376-1382. DOI: 10.1016/j.envpol.2018.09.114

Exposure, uptake and adverse effects on birds exposed to new and existing CMP3 priority organic flame retardants: identifying in vivo changes within an avian adverse outcome pathway

Focus of research: An adverse outcome pathway approach was used to determine the effects of organic flame retardants on wild and captive avian species. Wild birds’ blood was analysed to determine the presence and concentration of chemicals. In captive birds, the metabolism of these chemicals and their toxicological effects on physiology, behaviours, and the thyroid system were identified.

Results: Among other findings, this project showed that the resting metabolic rate and growth of Coturnix japonica was significantly reduced when exposed to triphenyl phosphate (TPHP). Embryonic exposure to TPHP had no effects on fear response or exploratory behaviour in Coturnix japonica chicks.

Publications: Tongue, A.D.W., Reynolds, S.J., Fernie, K.J., Harrad, S. 2019. Flame retardant concentrations and profiles in wild birds associated with landfill: A critical review. Environ. Pollut. 248 :646-658. DOI: 10.1016/j.envpol.2019.01.103

Atmospheric fate studies on CMP priority chemicals

Focus of research: The research was designed to assess sources of flame retardant emissions into the environment, their transport through the environment, and pathways of human exposure.

Results: There are a multitude of sources of flame retardants to air across cities and regions, and the research has increased understanding of Organophosphorus Esters (OPEs) emitted to the atmosphere and their transport and deposition into water bodies. It has also found that handheld electronic devices, notably cell phones, may either be sources or indicators of OPE exposure through hand-to-mouth and/or dermal uptake.

Publications: Saini, A., Clarke, J., Jariyasopit, N., Rauert, C., Schuster, J. K., Halappanavar, S., Evans, G., Su, Y., Harner, T. 2019. Flame retardants in urban air: A case study in Toronto targeting distinct source sectors. Environ. Pollut. 247, 89-97. DOI: 10.1016/j.envpol.2019.01.027

Rodgers, T.F.M., Truong, J.W., Jantunen, L.M., Helm, P.A., Diamond, M.L., Organophosphate Ester Transport, Fate, and Emissions in Toronto, Canada, Estimated Using an Updated Multimedia Urban Model. Environ. Sci. Technol., 2018, 52 (21), pp 12465–12474, DOI: 10.1021/acs.est.8b02576

Yang, C. , Harris, S., Jantunen, L., Siddique, S., Kubwabo C., Tsirlin, D., Latifovic, L., Fraser, B., St-Jean, M., De La Campa, R., You, H., Kulka, R., Diamond, M. Are cell phones an indicator of personal exposure to organophosphate flame retardants and plasticizers?, Vol.122, 104-116, Jan. 2019,

Long range transport of OPE flame retardants

Focus of Research: OPEs are believed to be arriving in the Arctic on ocean currents and via air transport. In this study, water samples were collected throughout the Canadian Arctic over several years to assess the levels and distribution of OPEs.

Results: OPEs were found in all abiotic environmental compartments in the Canadian North at higher levels than other contaminants including other flame retardants and pesticides. Levels of OPEs were found to be lower in the eastern Canadian Arctic than in the western Arctic.

Publications: Jantunen, L., Bernstein, S., Stern, G., Burt, A. Organophosphate Esters Flame Retardants and Plasticizers in the Canadian Arctic Waters. Society of Environmental Toxicology and Chemistry. Sacramento, California, USA, November 2018

First steps towards characterization of halogenated alkene flame retardants

Focus of research: Mass spectrometry techniques were used to determine the molecular composition of two halogenated alkenes, which are widely used as flame retardant additives and plasticizers but poorly understood.

Results: The results showed that the composition of the substance was quite different from what was assumed in an initial screening risk assessment conducted by the department. These new data will further inform ecological risk assessment of the substances.

Publications: Chibwe, L., Myers, AL., De Silva, AM., Reiner, EJ., Jobst, K., Muir, D., Yuan, B. C12-30 a-Bromo-Chloro “Alkenes”: Characterization of a Poorly Identified Flame Retardant and Potential Environmental Implications, which has been published in Environmental Science & Technology

Chronic toxicity of thiocarbamate, benzotriazole, and benzothiazole compounds to survival, growth, and reproduction of freshwater invertebrates

Focus of research: Chemicals from three groupings (thiocarbamates, benzotriazoles, and benzothiazoles) were assessed for their toxicity to aquatic invertebrates and bacteria living in sediments. The survival, growth, and reproduction of these organisms were analysed to determine the risk these chemicals pose to aquatic ecosystems.

Results: Thiocarbamates, benzotriazoles and benzothiazoles caused limited toxicity to aquatic invertebrates. Observed effects occurred at concentrations well above those measured in the environment for benzotriazoles. However, thiocarbamates and benzothiazoles were difficult to measure and there are limited data on environmental concentrations; therefore, more information is needed to assess the risks of these compounds to aquatic ecosystems.

Publications: Bartlett, A., Frank, R., Brown, L., Hedges, A., Vucic, J., Campbell, S., Rudy, M., Vanderveen, R., Shires, K. 2018. Chronic toxicity of thiocarbamate compounds to survival, growth, and reproduction of freshwater invertebrates. Environmental Toxicology and Chemistry. (In preparation)

Environmental fate and deposition of CMP3 priority polar organic substances

Focus of research: Trophic magnification of CMP3 priority substances (hindered phenol antioxidants (HPs), organophosphate ester plasticizers/flame retardants (OPEs), and benzotriazoles UV stabilizers (BZT-UVs)) in an urban, industrial aquatic food web and a remote, reference aquatic food web were investigated. Usage and release of selected substances (HPs and OPEs) were also explored by analyzing wastewater influent and effluent. Additionally, transformation products of HPs in wastewater and biota were investigated. This research was conducted to support toxic effects research via chemical analyses.

Results: The study generated the first data in water, sediment, biota and wastewater of CMP3 substances (such as hindered phenol antioxidants, organophosphate esters, and benzotriazole UV stabilisers) in the Canadian environment and contributed to the understanding of exposure, long-range transport, and food web biomagnification. As well, it contributed to the understanding of usage and persistence of these substances by measuring wastewater treatment plant influent, as well as emissions of these substances by investigating concentrations in effluent.

Publications: Lu, Z., De Silva, A.O., Provencher, J.F., Mallory, M.L., Kirk, J.L., Houde, M., Stewart, C., Braune, B.M., Avery-Gomm, S., Muir, D.C.G. 2019. Occurrence of substituted diphenylamine antioxidants and benzotriazole UV stabilizers in Arctic seabirds and seals. Science of the Total Environment. 663: 950–957

Lu, Z., Smyth, S.A., De Silva, A.O. 2019. Distribution and fate of synthetic phenolic antioxidants in various wastewater treatment processes in Canada. Chemosphere. 219, 826-835

Lu, Z., De Silva, A.O., Zhou, W., Tetreault, G.R., de Solla, S.R., Fair, P.A., Houde, M., Bossart, G., Muir, D.C.G. 2019. Substituted diphenylamine antioxidants and benzotriazole UV stabilizers in blood plasma of fish, turtles, birds and dolphins from North America. Science of the Total Environment. 647: 182-190

Chronic toxicity and modes of action of benzotriazoles and flame retardants in aquatic organisms

Focus of research: The presence of benzotriazoles (BZTs) and BZT-UV stabilisers (BZT‑UVs) in environmental samples were analyzed in order to better understand their fate and transport. The toxicity of these substances was also evaluated on model species of fish, algae, and invertebrate. As well, flame retardants (FRs) in environmental samples were determined and the chronic toxicity and molecular modes of action of three FRs were examined on freshwater invertebrates.

Results: Few chronic effects were observed for the selected BZT substances at environmentally relevant concentrations. Results indicate that exposure to the flame retardant substances studied affects important biological pathways at the molecular and protein levels, and could lead to long-term endocrine disruption through multiple generation.

Publications: Lu, Z., De Silva, A.O., Provencher, J.F., Mallory, M.L., Kirk, J.L., Houde, M., Stewart, C. Braune, B.M., Black, A., Muir, D.C.G. 2019. Accumulation of substituted diphenylamine antioxidants and benzotriazole UV stabilizers in Arctic seabirds and seals. Science of the Total Environment 663:950-957. DOI: 10.1016/j.scitotenv.2019.01.354

Survival, developmental toxicity, and tumour inducing potency of a model benzotriazole/benzothiazole (for example, 2-mercaptobenzothiazole) in fish – as a step towards an AOP for this class of compounds

Focus of research: The tumour-inducing potency of a model benzothiazole (2-mercaptobenzothiazole (2-MBTH)) was assessed in fish.

Results: Molecular level responses of fish that had been exposed to 2-MBTH were used to establish an adverse outcome pathway that extends from exposures of fish cells in vitro, to exposures of fish eggs, to tumor assessment in year old fish. Adverse outcome pathways can be used to aid risk assessments of other benzothiazoles in fish.

Publications: The results of this research were summarized in an internal technical report.

Other publications dealing with flame retardants:

Understanding the atmospheric fate and toxicity of engineered nanoparticles through transformation studies

Focus of research: The impact on the overall toxicity of airborne nanomaterials such as titanium oxide and silicon oxide when coated with secondary organic material found in the atmosphere, was investigated through laboratory studies.

Results: The results indicated that organic coatings on nanomaterials, as would occur in the atmosphere, significantly reduces the overall particle toxicity. This will be used to inform improvements to the risk assessment of nanomaterials released into the air.

Publication: Liu, Q., Liggio, J., Breznan, D., Thomson, E.M., Kumarathasan, P., Vincent, R., Li, K., Li, S. 2019. Oxidative and Toxicological Evolution of Engineered Nanoparticles with Atmospherically Relevant Coatings. Environ. Sci. Technol. 53, 3058-3066. DOI: 10.1021/acs.est.8b06879

Aquatic nanotoxicology

Focus of research: The impact of different types of freshwater on copper oxide nanoparticle toxicity was investigated.

Results: The toxicity of silver, zinc and copper nanoparticles were compared with the dissolved form in water and revealed that in general the nanoparticles were less toxic as particles. Additional testing was done on different sources of surface waters as green water (Great Lakes), brown water (Laurentian shield), urban (diluted municipal effluent in green water) and tap water (treated green water) looking at nanoparticles bioavailability and toxicity revealed that nanoparticles were generally more bioavailable in green water showing a potentially higher toxicity risk associated with Great Lakes sources.

Publications: Gagné, F., Auclair, J., Turcotte, P., Gagnon, C., Peyrot, C., Wilkinson, K. 2018. The influence of surface waters on the bioavailability and toxicity of zinc oxide nanoparticles in freshwater mussels. Comp Biochem Physiol C Toxicol Pharmacol.;219:1-11. DOI: 10.1016/j.cbpc.2019.01.005

Auclair J, Turcotte P, Gagnon C, Peyrot C, Wilkinson KJ, Gagné F. 2019. The influence of surface coatings on the toxicity of silver nanoparticle in rainbow trout. Comp Biochem Physiol C Toxicol Pharmacol. 2019 Dec;226:108623

Fate, transformation and bioaccumulation of silver nanoparticles (nAg) and metal oxide nanoparticles (nCeO2, nCuO, nZnO) in the aquatic environment

Focus of research: The fate and transformation of silver and metal oxide nanoparticles was analyzed based on their size, synthetic coating, and surrounding organic matter. The transformation products, bioavailability and bioaccumulation in aquatic organisms were evaluated.

Results: Natural transformation processes, such as aggregation or degradation, control the environmental fate and behavior of nanoparticles released into the environment. Particle size distributions change significantly under different natural conditions where most material was found in coarse colloidal fractions. The presence of natural humic substances slowed degradation of nanoparticles, which is characterized by the increase of small ion complexes and the detection of small colloids. Half-life values for silver nanoparticles were generally estimated to be less than 12 days under natural conditions, indicating transformation by-products must be considered in risk assessment studies.

Publications: Gagnon C. 2018. Silver nanoparticles in municipal wastewaters and environmental fate. Nano Res. Appl. 4: 53. DOI: 10.21767/2471-9838-C3-013

Fate and effects of nanotechnology in bacterial cultures and complex communities

Focus of research: Selected metal, carbon and silica nanomaterials were evaluated for their ecotoxicological potential focusing on microorganisms, using pure cultures and aquatic microbial communities. Multiple endpoints were studied including diversity, activity, biomass, ratios of live:dead cells, and reactive oxygen species production. As well, parallel studies based on transcriptomic and proteomic analyses were conducted.

Results: Frameworks were elaborated to inform the utilization of read-across approaches for the fate and effects of different nanomaterials.

Publications: Lawrence, J.R., Swerhone, G.D.W., Roy, J., Paule, A., Chekabab, S., Korber, D.R. 2019. Comparative molecular, genomic and microscale analysis of the effects of nanocrystalline cellulose on the structure and function of river biofilm communities. Ecotoxicology. (Submitted)

Environmental fate, effects and bioaccumulation of priority nanomaterials in soil

Focus of research: The effect of metal nanomaterials (nano copper (II) oxide and nano cerium (IV) oxide) on soil invertebrate species and indigenous microorganisms in agricultural soil were examined, with and without biosolid amendment. This also included an evaluation of the bioaccumulation potential in earthworms over time at sublethal levels.

Results: Among other findings, this project determined the conditions and concentrations at which selected metal nanomaterials exert adverse effects on soil microbial growth, activity and diversity.

Publications: Samarajeewa, A., Velicogna, J., Schwertfeger, D., Jesmer, A., Subasinghe, R., Princz, J., Scroggins, R., Beaudette, L. 2019. Assessment of the soil microbial community in a sandy loam soil amended with biosolids containing nano-silver particles. NanoImpact 14:100157. DOI: 10.1016/j.impact.2019.100157

The environmental fate, distribution and effects of naphthalene sulfonic acids (NSAs): Developing analytical methods, investigating toxicity, and evaluating bioaccumulation

Focus of research: Analytical methods were developed for the determination of NSAs in water, wastewater (effluent and influent), sediments, and tissues (worms, freshwater mussels, frogs and snapping turtle). The analytical methods were used to support investigations of NSA toxicity to and bioaccumulation in a variety of indicator species. In addition, the environmental mobility and bioavailability of NSAs and their environmental fate and distribution was studied.

Results: Analytical methods were developed for three NSAs (dinonylnaphthalenedisulfonic acid, DNDS; Calcium bis(2,3-dinonylnaphthalene-1-sulfonate), CaDNS; and Barium bis(2,3-dinonylnaphthalene-1-sulfonate), BaDNS). CaDNS and BaDNS appear to bind irreversibly to sediments and sand, while DNDS does not, suggesting that CaDNS and BaDNS are less mobile in the environment. Acute toxicity tests conducted with H. azteca, P. pilsbryi, L. cardium, and L. siliquoidea showed toxicity: CaDNS ~ BaDNS > DNDS. Chronic toxicity tests conducted with H. azteca and T. tubifex showed toxicity: CaDNS ~ BaDNS > DNDS, with sediment having a protective effect, consistent with findings in mobility experiments. Toxicity tests conducted with S. tropicalis revealed deformation and developmental delays in metamorphosis.

Publications: Matten, K.J. Toxicity of dinonylnaphthalene sulfonates in overlying water on the pelagic Pimephales promelas, larval freshwater mussels, and epibenthos. (In preparation)

Source, environmental fate and toxicity of synthetic musks in Canada

Focus of research: The levels of synthetic musk compounds (SMCc) in air, water, and sediment in the environment were assessed to determine how their usage and releases have changed over the last decade. Urban sources of SMCs were investigated through the analysis of air, soils and surface water samples from a wide array of land-use types and urban densities. The release of synthetic musk compounds from wastewater treatment plants to air and aquatic environments was assessed, as well as their levels in the Great Lakes Basin and whether they can be carried by air currents to the remote Arctic were also examined.

Results: Polycyclic musks were found to be the most abundant musk compounds in urban areas. Their sources to the outdoor environment originated from releases from indoor air and volatilization from wastewater treatment plants during the treatment process. SMCs were not found in remote Arctic air indicating low potential for long-range atmospheric transport. Results will be used to improve the risk assessment of SMCs in the urban environment.

Publications: Wong, F., Robson, M., Melymuk, L. Shunthirasingham, C. Alexandrou, N., Shoeib, M., Luk, E., Helm, P., Diamond, M. L., Hung, H. 2019. Urban sources of synthetic musk compounds to the environment. Environ. Sci.: Processes Impacts, 21, 74. DOI: 10.1039/C8EM00341F

Fate of microplastics in the Arctic environment

Focus of research: The research aimed to determine the extent of microplastic contamination across the Canadian Arctic archipelago and Hudson Bay marine systems, and to evaluate sources and transport pathways of the microplastics.

Results: Microplastics were found in the arctic snow, water sediment and zooplankton. They are ubiquitous and consist mostly of small fibres. These results provide insight into the source, transport, fate and entry of microplastics into the Arctic food chain.

Publications: Adams, J., Jantunen, L., Diamond, M. L., Finkelstein, S. A., Rochman, C. M., Bernstein, S., Stern, G., Understanding sources and transport of microplastic pollution to the Canadian Arctic, SETAC Europe, Helsinki Finland, May 2019

HC research

HC funded 26 CMP research projects in 2018-2019. These projects address departmental and international priorities and cover a number of subjects such as characterization of nanomaterials, toxicological response to nanomaterials, carcinogenic potential of chemicals, genetic toxicity assessment, hazard characterization and identification of biotechnology microbes.

In vitro to in vivo extrapolation (IVIVE) toxicokinetics of CMP chemicals

Focus of research: The goal of this research is to develop better in-vitro toxicokinetic (TK) data and consistent biological extrapolation models to predict realistic doses in-vivo where potential toxicological effects would be anticipated based on measures from high throughput in-vitro assay toxicity databases. Tests and models focus on substances recently used as replacements for plasticizers, flame retardants and perfluorinated chemicals.

Results: The project resulted in the development of a new software platform to screen and model high throughput screening (HTS) data. This software, named DREAM-TK, allows data users to analyze and visualize HTS toxicity and in-vitro TK data. This tool helps in identifying chemicals considered safe and/or to trigger additional testing.

Publications: This research has provided information for the preparation of new draft documents for various international collaborations such as those facilitated by the Organisation for Economic Cooperation and Development (OECD) chemical safety programs.

The impact of dissolution behaviour of metal oxide nanomaterials on toxicological response

Focus of research: HC is responsible for assessment and management of risks associated with engineered nanomaterials (materials in a size range of 1-100 nanometers). The toxicological behavior of nanomaterials (NMs) is closely associated with their distinct physical-chemical properties. This research is investigating the influence of dissolution behaviour of NMs on their toxic potential.

Results: The results of this research resulted in the development of a method that made a significant contribution to the understanding of lung bioaccessibility of platinum group elements in the thoracic fraction of re-suspended road dust. The results will inform HC risk assessments and will help HC meet its 2017-2021 commitments associated with the OECD Working Party on Manufactured Nanomaterials (WPMN).

Publications: Avramescu, M-L., Chénier, M., Gardner, HD., Rasmussen, P.E. (2019) Solubility of metal oxide nanomaterials: observations on method development. Journal of Physics Conference Series, 1323:1

Characterization of residential exposures to CMP metals and organics-creation of a data repository for the Canadian House Dust Study (CHDS)

Focus of research: The objective of this research is to provide information on indoor environmental exposures (metals and synthetic organic compounds) using nationally representative house dust samples. The study focuses primarily on childhood exposures to house dust through normal hand-to-mouth ingestion behavior but looks also at potential inhalation exposures by characterizing re-suspended dust in carpeted versus non-carpeted homes.

Results: The results showed that metal concentrations in settled house dust are often correlated with those in the personal breathing zone. Therefore, settled dust data are useful for estimating indoor and personal exposures by inhalation, in addition to exposure via ingestion. Results were used to support HC's risk assessment and management activities, with particular focus on mitigation of childhood residential exposures to chemical substances.

Publications: Rasmussen, P., Levesque, C., Chénier, M., and Gardner, H.D. Contribution of metals in resuspended dust to indoor and personal inhalation exposures: Relationships between PM10 and settled dust. Building and Environment. Volume 143, 1 October 2018, Pages 513-522. DOI:10.1016/j.buildenv.2018.07.044

Shang, H., Fan, X., Kubwabo, C., Rasmussen, P.E. Short-chain and Medium-chain Chlorinated Paraffins in Canadian House Dust and NIST SRM 2585. Environmental Science and Pollution Research, 2019

Development and validation of rapid methods to assess endocrine toxicity

Focus of research: There are growing concerns that exposures to commercial chemicals cause harm by interfering with the hormonal control of growth and development of the brain, reproductive tract and lead to metabolic and stress-related problems. Developing rapid methods to identify chemicals posing these hazards is a critical need for safety assessment. This project will 1) identify and characterize the molecular target(s) mediating toxicity of organophosphate flame retardants and 2) establish methods to screen for molecules that impair thyroid hormone signaling.

Results: Enzyme targets of flame retardant toxicity were identified in all affected organs. Detailed structure activity studies of enzyme inhibition have been completed for liver target and for human homolog enzyme. This project contributes to a global initiative to characterize the molecular targets influenced by hazardous substances and to develop validated, high throughput methods to rapidly screen chemicals for toxicity and to set priorities for further assessment.

Publications: Dong, H., Atlas, E., Wade, MG. 2019. Development of a non-radioactive screening assay to detect chemicals disrupting the human sodium iodide symporter activity. Toxicol. In Vitro. 57:39-47. doi: 10.1016/j.tiv.2019.01.021

GeneTox21 - an integrated, high-throughput (HT) platform for in vitro genetic toxicity assessment of new and existing chemicals

Focus of research: Genetic damage is associated with numerous human diseases, and chemical screening programs routinely assess a chemical’s ability to damage DNA (that is, genetic toxicity). Traditional assessment tools (that is, bioassays) are laborious and not conducive to HT, high-content chemical screening using tools that employ cultured cells (that is, in vitro bioassays). This project is developing an integrated, multi-assay, HT platform for the assessment of chemically-induced genetic toxicity.

Results: The results showed advancement towards validation of the cell in vitro transgene mutagenicity assay, and the establishment of an in vitro mutagenicity assay. For the former, a miniaturized protocol was developed to assess the effects of various treatment times and post-exposure sampling times. The HT platform, which is called GeneTox21, will be internationally promoted to encourage its adoption for robust genetic toxicity assessment of new and existing substances.

Publications: Cox, J.A., Zwart, E., Luijten, M. 2018. The development and pre-validation of an in vitro mutagenicity assay based on MutaMouse primary hepatocytes, Part I: Isolation, structural, genetic and biochemical characterization. Environmental and Molecular Mutagenesis 60:331-347

Cox, J.A., Zwart, E., Luijten, M. 2019. The development and pre-validation of an in vitro mutagenicity assay based on MutaMouse primary hepatocytes, Part II: Assay performance for the identification of mutagenic chemicals. Environmental and Molecular Mutagenesis. 60:348-360

Refining and deploying a quantitative framework for the analysis and regulatory interpretation of genetic toxicity dose-response data

Focus of research: This project is using dose-response data from the scientific literature to determine the levels of genotoxic effects (for example, DNA damage or genetic mutations) that should be considered adverse. As a follow-up, the work is conducting case studies of selected chemicals to evaluate the ability to use analyses of dose-response data to assess the risk of adverse human health effects; that is, adverse effects on the genome.

Results: Procedures were developed and implemented to effectively and efficiently analyze large amounts of dose-repose data generated using a cell-based genetic toxicity bioassay known as the ToxTracker assay. The dose-response data were also adjusted for levels of cytotoxicity. Additionally, the scope of several case studies to evaluate the risk of adverse human health effects was expanded. The results obtained will be used to develop a framework for routine quantitative use of genetic toxicity data for regulatory evaluations of new and existing chemicals. Interactions with stakeholders will permit an evaluation of the proposed framework, and international promotion of quantitative methods for regulatory evaluations of genotoxic chemicals.

Publications: White, P.A., Zeller, A., Pfuhler, S., Johnson, G.E. 2019. R e: Gi et al. 2018, In vivo positive mutagenicity of 1,4-dioxane and quantitative analysis of its mutagenicity and carcinogenicity in rats. Archives of Toxicology 92:3207-3221. Arch Toxicol 93:211-212

Relative toxic potency of silica and titanium dioxide nanoparticle variants

Focus of research: The objective is to assess composition, size and surface coating characteristics of nanomaterial (NMs), and test toxicity in lung cells including cells from biopsy samples from healthy lungs and those affected by pulmonary diseases (for example, cystic fibrosis).

Results: From early findings, macrophages exposed to silica nano particles (SiNPs) showed different responses based on size and surface-modification. Also, SiNPs were relatively more cytotoxic than titanium oxide nanoparticles, and atmospheric changes appeared to alter these toxicities. Furthermore, internalization of nanoparticles into exposed cells and changes in cellular organelles were noticed with size- and surface-modification appearing to play key roles in influencing these biological responses (for example, oxidative stress). This work will advance our understanding on the health consequences of exposure to NMs, and assist in the design of less toxic NMs.

Publications: Liu, Q., Liggio, J., Breznan, D., Thomson, EM., Kumarathasan, P., Vincent, R., Li, K., Li, SM. Oxidative and Toxicological Evolution of Engineered Nanoparticles with Atmospherically Relevant Coatings. Environ Sci Technol. (Accepted in 2018). 2019 Mar 19;53(6):3058-3066. doi: 10.1021/acs.est.8b06879

Breznan D, Das DD, MacKinnon-Roy C, Bernatchez S, Sayari A(1), Hill M, Vincent R, Kumarathasan P. Physicochemical Properties Can Be Key Determinants of Mesoporous Silica. Nanoparticle Potency in Vitro. ACS Nano. 2018 Dec 26;12(12):12062-12079

An integrated testing strategy to assess somatic and germ cell mutations using the OECD’s transgenic rodent test guideline TG 488 and the MutaMouse model

Focus of research: The objective is to harmonize the experimental design to identify somatic and germline mutations at a single time point. This integrated approach will significantly reduce the number of animals that are needed for the testing of chemicals for regulatory purposes.

Results: Data generated by this project have been used by the OECD to update the recommended experimental design in one test guideline that is routinely used to assess the ability of chemicals to induce mutations (that is, changes in the sequence of the DNA).

Publications: Marchetti F., Aardema, M., Beevers, C., van Benthem, J., Godschalk, R., Yauk, CL., Young, B., Williams, A., Douglas, GR. (2018) Identifying germ cell mutagens using OECD test guideline 488 (transgenic rodent somatic and germ cell mutation assay) and integration with somatic cell testing. Mutation Research, 832:7-18. Epub: May 29, 2018

6.2 Living organisms

Government research on living organisms focuses on developing novel and contemporary methods for determining the hazardous characteristics and the pathogenicity potential of various existing and emerging biotechnology microbes in order to support regulatory risk assessments. The research is jointly coordinated between regulators at HC and ECCC.

Research in 2018-2019 continued on a number of subjects, and 5 laboratory protocols to assess pathogenicity were provided to regulators as a reference for notifiers.

6.3 Air pollutants and greenhouse gases (GHGs)

Air quality research efforts help quantify priority air pollutants and determine trends, improve and validate air quality predictions both in the near term and into the future within the national and global context. These efforts also enhance understanding of the impacts of air pollution on Canadians and the environment. The research also tackles emerging issues and underpins and informs evidence-based policy and regulatory development.

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 (O3), and particulate matter/aerosols. It also included utilizing surface and satellite observations; measuring the impact of ship emissions and the formation of secondary species formed in the Arctic environment. Over 67 research papers were published in peer-reviewed scientific journals in 2018-2019. The following are representative examples of that important body of work.

Satellite-based measurement of emissions of ammonia and NOx

Focus of research: The derivation of emissions of ammonia and NOx from various sources, including wildfires, using satellite data.

Results: The research found there was good agreement between the satellite measurements, model predictions and emissions inventories, suggesting that satellite data can contribute to improved understanding and quantification of air pollutant emissions.

Publications:Adams, C., McLinden, C.A., Shephard, M.W., Dickson, N., Dammers, E., Chen, J., Makar, P., Cady-Pereira, K.E., Tam, N., Kharol, S.K., Lamsal, L.N., Krotkov, N.A., Satellite-derived emissions of carbon monoxide, ammonia, and nitrogen dioxide from the 2016 Horse River wildfire in the Fort McMurray area, Atmos. Chem. Phy., Vol. 19, 4, Feb. 2019, 2577-2599, 10.5194/acp-19-2577-2019

Zhang, X., Jones, D.B.A., Keller, M., Walker, T.W., Jiang, Z., Henze, D.K., Worden, H.M., Bourassa, A.E., Degenstein, D.A., Rochon, Y.J., Quantifying Emissions of CO and NOx Using Observations From MOPITT, OMI, TES, and OSIRIS, Journal of Geophysical Research: Atmospheres, Vol. 214, 2, Jan. 2019, 1170-1193,

Griffin, D., Zhao, X., McLinden, C.A., Boersma, F., Bourassa, A., Dammers, E., Degenstein, D., Eskes, H.,Fehr, L., Fioletov, V., Hayden, K., Kharol, S.K.a, Li, S.-M.a, Makar, P., Martin, R.V., Mihele, C., Mittermeier, R.L., Krotkov, N., Sneep, M., Lamsal, L.N., Linden, M.T., Geffen, J.V., Veefkind, P., Wolde, M., High-Resolution Mapping of Nitrogen Dioxide With TROPOMI: First Results and Validation Over the Canadian Oil Sands, Geophysical Research Letters, 46, 3, Dec. 2018

Global and regional trends of SO2 and nitrogen

Focus of study: An assessment of global and regional trends of sulphur in the atmosphere was conducted, and exceedances of ecosystem critical loads for acidifying deposition of nitrogen and sulphur in Alberta and Saskatchewan were identified.

Results: The research provided insights into where global sulphur emissions have increased or decreased between 1990 and 2015, and included the identification of nearly 40 emissions sources not previously captured in global emissions inventories. The related critical loads work identified that ecosystems in portions of Alberta and Saskatchewan have exceeded their ability to buffer acid deposition.

Publications: Aas, W., Mortier, A., Bowersox, V., Cherian, R., Faluvegi, G., Fagerli, H., Hand, J., Klimont, Z., Galy-Lacaux, C., Lehmann, C.M.B., Myhre, C.L., Myhre, G., Olivié, D., Sato, K., Quaas, J., Rao, P.S.P., Schulz, M., Shindell, D., Skeie, R.B., Stein, A., Takemura, T., Tsyro, S., Vet, R., Xu, X., Global and regional trends of atmospheric sulfur, Scientific Reports, Vol. 9, 11, Jan. 2019, 9533

Liu, F., Choi, S.B,, Li, C., Fioletov, V.E., McLinden, C.A., Joiner, J., Krotkov, N.A., Bian, H., Janssens-Maenhout, G., Darmenov, A.S., Da Silva, A.M. A new global anthropogenic SO2 emission inventory for the last decade: A mosaic of satellite-derived and bottom-up emissions, Atm. Chem Phys., Vol 18, Issue 22, 22 November 2018, Pages 16571-16586

Makar, P. A., Akingunola, A., Aherne, J., Cole, A. S., Aklilu, Y.-A., Zhang, J., Wong, I., Hayden, K., Li, S.-M., Kirk, J., Scott, K., Moran, M. D., Robichaud, A., Cathcart, H., Baratzedah, P., Pabla, B., Cheung, P., Zheng, Q., Jeffries, D. S. (2018) Estimates of exceedances of critical loads for acidifying deposition in Alberta and Saskatchewan, Atmos. Chem. Phys., 18, 9897-9927

Monitoring of atmospheric ozone and ultraviolet radiation

Focus of research: The measurement of atmospheric ozone, aerosol and water vapour using an ECCC-developed lidar (Light Detection and Ranging) instrument was validated, and ECCC scientists contributed to an international assessment of ozone in the layer of the atmosphere nearest the surface of the Earth.

Results: The assessments of new lidar and of established satellite measurement technologies demonstrated that both remote sensing techniques are highly useful and efficient methods to collect data. Analysis of satellite measurements of tropospheric ozone did not identify any clear trends in the global levels; the analysis of ultraviolet radiation trends found that levels at various locations in the northern hemisphere over the past 25 years vary considerably due mainly to the variations in airborne aerosols and total ozone, but the relationship between these factors requires further research.

Publications: Strawbridge, K.B., Travis, M.S. Firanski, B.J., Brook, J.R., Staebler, R., Leblanc, T., A fully autonomous ozone, aerosol and nighttime water vapor lidar: A synergistic approach to profiling the atmosphere in the Canadian oil sands region, Atoms. Environ, Volume 11, Issue 12, 19 December 2018, Pages 6735-6759, doi:10.5194/amt-11-6735-2018

Gaudel, A.. Cooper, O. R., Ancellet, G., Barret, B., Boynard, A., Burrows, J. P., Clerbaux, C., Coheur, P.F,. Cuesta, J., Cuevas, E., Doniki, S., Dufour, G., Ebojie, F., Foret, G., Garcia, O., Granados Muños, M. J., Hannigan, JW., Hase, F., Huang, G., Hassler, B., Hurtmans, D., Jaffe, D., Jones, N., Kalabokas, P., Kerridge, B., Kulawik, S. S., Latter, B., Leblanc, T., Le Flochmoën, E., Lin, W., Liu, J., Liu, X., Mahieu, E., McClure-Begley, V., Neu, J. L., Osman, M., Palm, M., Petetin, H., Petropavlovskikh, I., Querel, R., Rahpoe, N., Rozanov, A., Schultz, M. G., Schwab, J., Siddans, R., Smale, D., Steinbacher, M., Tanimoto, H., Tarasick, D. W., Thouret, V., Thompson, A. M., Trickl, T., Weatherhead, E., Wespes, C., Worden, H. M., Vigouroux, C., Xu, X., Zeng, G., and  Ziemke,J. Tropospheric Ozone Assessment Report: Present-day distribution and trends of tropospheric ozone relevant to climate and global atmospheric chemistry model evaluation. Elem Sci Anth 2018; 6 (1): 39, doi: 10.1525/elementa.291

Fountoulakis, I., Zerefos, C.S., Bais, A.F., Kapsomenakis, J., Koukouli, M.-E., Ohkawara, N., Fioletov, V., De Backer, H., Lakkala, K., Karppinen, T., Webb, A.R., Twenty-five years of spectral UV-B measurements over Canada, Europe and Japan: Trends and effects from changes in ozone, aerosols, clouds, and surface reflectivity, Comptes Rendus Geoscience External Geophysics, Climate, 350,7, Nov 2018, 393-402, 10.1016/j.crte.2018.07.011

Regional and global sources of aerosols and particulate matter (PM)

Focus of research: ECCC scientists participated in a study of global sources of fine PM, conducted studies on the impacts of wildfire smoke on ecosystems, and conducted an extensive overview of recent advances in understanding the sources and chemical processes affecting PM in the Arctic and their effect on Arctic climate.

Results: Fine PM was found to originate from a variety of sources - just over half coming from residential energy use, industry and power generation. Dense wildfire smoke negatively impacts the ability of forests to absorb carbon from the atmosphere, leading them to become net sources of carbon instead.

Publications: In 2018-2019, ECCC scientists contributed to many publications related to aerosols and fine particulate matter; a few examples include:

Weagle, C.L., Snider, G., Li, C., Van Donkelaar, A., Philip, S., Bissonnette, P., Burke, J., Jackson, J., Latimer, R., Stone, E., Abboud, I., Akoshile, C., Anh, N.X., Brook, J.R., Cohen, A., Dong, J., Gibson, M.D., Griffith, D., He, K.B., Holben, B.N., Kahn, R., Keller, C.A., Kim, J.S., Lagrosas, N., Lestari, P., Khian, Y.L., Liu, Y., Marais, E.A., Martins, J.V., Misra, A., Muliane, U., Pratiwi, R., Quel, E.J., Salam, A., Segev, L., Tripathi, S.N., Wang, C., Zhang, Q., Brauer, M., Rudich, Y., Martin, R.V., Global Sources of Fine Particulate Matter: Interpretation of PM2.5 Chemical Composition Observed by SPARTAN using a Global Chemical Transport Model, Environ. Sci. Technol., 2018, 52 (20), pp 11670–11681. DOI: 10.1021/acs.est.8b01658

McKendry, I. G., Christen, A., Lee, S.-C., Ferrara, M., Strawbridge, K. B., O'Neill, N., Black, A.: Impacts of an intense wildfire smoke episode on surface radiation, energy and carbon fluxes in southwestern British Columbia, Canada, Atmos. Chem. Phys., 19, 835-846,, 2019

Abbatt, J.P.D., Leaitch, R., W., Aliabadi, A.A., Bertram, A.K., Blanchet, J.-P., Boivin-Rioux, A., Bozem, H., Burkart, J., Chang, R.Y.W., Charette, J., Chaubey, J.P., Christensen, R.J., Cirisan, A., Collins, D.B., Croft, B., Dionne, J., Evans, G.J., Fletcher, C.G., Gali, M., Ghahremaninezhad, R., Girard, E., Gong, W., Gosselin, M., Gourdal, M., Hanna, S.J., Hayashida, H., Herber, A.B., Hesaraki, S., Hoor, P., Huang, L., Hussherr, R., Irish, V.E., Keita, S.A., Kodros, J.K., Köllner, F.g,, Kolonjari, F., Kunkel, D., Ladino, L.A., Law, K., Levasseur, M., Libois, Q., Liggio, J., Lizotte, M., MacDonald, K.M.,Mahmood, R., Martin, R.V., Mason, R.H., Miller, L.A., Moravek, A., Mortenson, E., Mungall, E.L., Murphy, J.G., Namazi, M., Norman, A.-L., O'Neill, N.T., Pierce, J.R., Russell, L.M., Schneider, J., Schulz, H., Sharma, S., Si, M., Staebler, R.M., Steiner, N.S., Thomas, J.L., Von Salzen, K., Wentzell, J.J.B., Willis, M.D, Wentworth, G.R., Xu, J.-W., Yakobi-Hancock, J.D., Overview paper: New insights into aerosol and climate in the Arctic, Atoms. Chem. Phy., vol. 19, 4, Feb. 2019, 2527-2560, 10.5194/acp-19-2527-2019

Air pollution from the transportation sector

Focus of research: Studies were conducted to improve the measurement of black carbon (BC) emitted by small marine engines and diesel vehicles, examine air pollution near roadways, and assess the impact of air pollutant emissions from marine shipping in the Canadian Arctic.

Results: The research on small marine engines indicated that differences in measured BC emissions relate to engine characteristics, loads and the fuel used. The near-roadway study indicated that larger vehicles are the most influential factor affecting the level of the measured pollutants. Research showed that the properties of BC particles depend greatly on particle size. Marine shipping was found to be a small contributor of O3 and PM, but a significant contributor of nitrogen dioxide (NO2) and SO2 over Arctic shipping channels.>

Publications: Jiang, Y., Yang, J., Gagné, S., Chan, T.W., Thomson, K., Fofie, E., Cary, R.A., Rutherford, D., Comer, B., Swanson, J., Lin, Y., Rooy, P.V., Asa-Awuku, A., Jung, H., Barsanti, K., Karavalakis, G., Cocker, D., Durbin, T.D., Miller, J.W., Johnson, K.C. (2018) Sources of variance in BC mass measurements from a small marine engine: Influence of the instruments, fuels and loads. Atmospheric Environment 182: 128-137.

Wang, J.M., Jeong, C.-H., Hilker, N., Shairsingh, K.K., Healy, R., Sofowote, U., Debosz, J., Su, Y., McGaughey, M., Doerksen, G., Munoz, T., White, L., Herod, D., Evans, G.J. Near-Road Air Pollutant Measurements: Accounting for Inter-Site Variability using Emission Factors, Env. Sci. & Tech., 2018 52 (16), 9495-9504, DOI: 10.1021/acs.est.8b01914

Gong, W., Beagley, S.R., Cousineau, S., Sassi, M., Munoz-Alpizar, R., Ménard, S., Racine, J., Zhang, J., Chen, J., Morrison, H., Sharma, S., Huang, L., Bellavance, P. , Ly, J., Izdebski, P., Lyons, L., Holt, R., Assessing the impact of shipping emissions on air pollution in the Canadian Arctic and northern regions: Current and future modelled scenarios, Atoms. Chem. Phys., Volume 18, Issue 22, 26 November 2018, Pages 16653-16687, 10.5194/acp-18-16653-2018

Emissions from oil sands activities

Focus of research: Under the Oil Sand Monitoring program (OSM), ECCC scientists assessed the contribution of oil sands operations to regional emissions of air pollutants and GHGs using aircraft-based measurements.

Results: ECCC research contributed to improvement in the quantification of emissions from oil sands activities in Canada.

Publications: Stroud, C. A., Makar, P. A., Zhang, J., Moran, M. D., Akingunola, A., Li, S.-M., Leithead, A., Hayden, K., Siu, M.: Improving air quality model predictions of organic species using measurement-derived organic gaseous and particle emissions in a petrochemical-dominated region, Atmos. Chem. Phys., 18, 13531-13545,, 2018

Baray, S., Darlington, A., Gordon, M., Hayden, K. L., Leithead, A., Li, S.-M., Liu, P. S. K., Mittermeier, R. L., Moussa, S. G., O'Brien, J., Staebler, R., Wolde, M., Worthy, D., McLaren, R.: Quantification of methane sources in the Athabasca Oil Sands Region of Alberta by aircraft mass balance, Atmos. Chem. Phys., 18, 7361-7378,, 2018

Enhanced methane emissions from a warming Canadian Arctic

Focus of research: ECCC scientists looked at methane measurements from four monitoring stations in the Canadian sub-Arctic and used computer models to determine the relative contributions to atmospheric methane concentrations from wetland and forest fire sources.

Results: This study showed a correlation with warmer summer conditions resulting in higher methane emissions from wetlands at the sub-Arctic sites studied. ECCC scientists are conducting a similar study using data from additional measurement sites across Canada to understand methane emissions from wetlands on the national scale.

Publications: Ishizawa, M., Chan, D., Worthy, D., Chan, E., Vogel, F., Maksyutov, S. (2019): Analysis of atmospheric CH4 in Canadian Arctic and estimation of the regional CH4 fluxes, Atmospheric Chemistry and Physics, 19, 4637–4658,

HC research

In 2018-2019, HC continued to conduct research on human exposure to indoor and outdoor air pollutants and their health impacts in order to guide actions to address air pollution by governments, industries, other organizations and individuals. HC scientists published approximately 44 articles in peer reviewed scientific journals. These addressed issues such as global estimates of mortality associated with air pollution exposure, risk factors that contribute to the estimation of the global burden of disease, gene environment interactions as they relate to air pollution, the effect of air pollution on birth outcomes, the benefits of kitchen exhaust fans in improving indoor air quality, and studies of the relationship between air pollution exposure and hypertension, diabetes and Parkinson’s disease. Others studies investigated determinants of air pollution exposure in various environments and provided information of use to local air quality management and population health studies.

Twenty-one HC research projects on air quality were ongoing in 2018-2019 and 3 new research projects were initiated. The new studies included investigations of aeroallergens and air pollution, ultrafine particles (UFPs) and cancer, and the effect of biomass burning emissions on children’s health. The following presents some of the projects in which HC was engaged during 2018-2019.

ATOUSSA - Assessing Toxicity of Organics in Urban Source Sectors for Air

Focus of research: This study investigates potential human health risks associated with exposure to chemical mixtures in urban air. The objective is to identify various toxic organics and characterise their relative concentrations at different sites in urban Toronto influenced by different types of emission sources.

Results: The project generated knowledge of the chemical composition of eight different sites indicative of different sources in the Toronto urban area and how the chemical composition changes from season to season. Several toxicity assays were optimised to determine the most sensitive assays that will enable differentiation of site-specific responses that can be linked to specific chemical components and their respective concentrations in the mixtures. The current study provided a level of comparison with and between various sources in the Toronto region.

Publications: Saini, A., Clarke, J., Jariyasopit, N., Rauert, C., Schuster, J.K., Halappanavar, S., Evans, G.J., Su, Y., Harner, T. Flame Retardants in Urban Air: A Case Study in Toronto Targeting Distinct Source Sectors. Environmental Pollution; Volume 247, April 2019, Pages 89-97

Analysis of indoor air VOC data collected in Canadian Health Measures Survey (CHMS): National estimates of indoor air VOCs and determinants of indoor air VOCs

Focus of research: Under the CHMS, a population-based national indoor air survey (NIAS) was conducted for the presence of VOCs in the indoor air of Canadian homes. The goal is to examine associations between levels of indoor air VOCs and housing type (houses vs. apartments), lifestyle (smoking vs. non-smoking) and seasons (monthly variation).

Results: About two-thirds of the 88 VOCs measured in the cycle 3 of the CHMS were detected in more than half of the homes, and that VOC levels are comparable to those of cycle 2 for the majority of measured VOCs. Information on indoor air VOCs can be used to assess human inhalation exposure to these chemicals and to inform the development of residential indoor air quality guidelines for individual VOCs.

Publications: Li, Y., Cakmak, S. Zhu, J. Profiles and monthly variations of selected volatile organic compounds in indoor air in Canadian homes: results of Canadian national indoor air survey 2012-2013. Environment International (2019), 126, 134–144

The role of non-chemical stressors and stress susceptibility in modifying the effects of air pollutants on health

Focus of research: Non-chemical stressors are important determinants of health that may also modify or contribute to the adverse health effects associated with air pollution. The objective is to assess the extent to which non-chemical stressors and inter-individual differences in stress response modify health effects of air pollution.

Results: The study produced the first evidence that individual differences in stress reactivity are associated with differential sensitivity to pulmonary impacts of ozone. The first national profile of allostatic load, a measure of cumulative physiological dysfunction associated with chronic exposure to stressors, was published. There was a spatial association identified between psychological distress and ambient air pollution levels in Canada. This work provides insight into factors governing susceptibility to inhaled pollutants. The allostatic load profile provides a tool for assessing combined and cumulative impacts of exposure to multiple stressors.

Publications: Thomas, J., Guénette, J., Thomson, EM. Stress axis variability is associated with differential ozone-induced lung inflammatory signaling and injury biomarker response. Environ Res. 2018 Sep 8. pii: S0013-9351(18)30496-1. doi: 10.1016/j.envres.2018.09.007

Thomas J, and Thomson EM. Dec 2018. Corticosterone determination in bronchoalveolar lavage fluid and its relationship to free and total plasma corticosterone. Anal Biochem. 2019 Feb 15; 567:27-29. doi:10.1016/j.ab.2018.12.005

Air Quality Health Index (AQHI) panel and intervention studies oxidative stress markers and additional data analysis

Focus of research: This project proposed to analyze oxidative stress markers for Prince George 2015 and London 2015, to analyze associations between the AQHI and individual pollutants and cardiorespiratory measures in the London 2015 data, and to conduct additional analyses of panel and intervention study data, including subgroup analyses and alternative weightings of pollutants in the AQHI formulation.

Results: The study found short term adverse effects on heart and lung function with increases in the AQHI, as well as benefits to the heart and lungs over the duration of the study from daily outdoor physical activity. These findings suggest that older adults living in smaller cities and rural areas benefit from daily light outdoor physical activity in winter, but may also benefit from reducing outdoor activity when the AQHI is particularly high in order to reduce short-term adverse effects on the heart and lungs.

Publications: Stieb, DM., Shutt, R., Kauri, LM., Szyszkowicz, M., Dobbin, NA, Chen, L., Rigden, M., Van Ryswyk, K., Kulka, R., Jovic, B., Mulholland, M., Green, MS, Liu, L., Pelletier, G., Weichenthal, SA., Dales, RE. "Cardiorespiratory effects of air pollution in a panel study of winter outdoor physical activity in older adults. " Journal of occupational and environmental medicine 60.8 (2018): 673-682

Oxidative stress, inflammation and cardiovascular changes associated with oxidative potential of ambient coarse, fine and ultrafine PM

Focus of research: PM in ambient air is a complex mixture of various sizes and constituents. Oxidative stress/inflammation is thought to be an important pathway leading to PM-associated disease status. This has led to a hypothesis that oxidative potential (OP) may be an integral property of PM that initiates oxidative stress/inflammation in the body. This project will provide evidence as to how reactive constituents of ambient PM of different size fractions/sources may affect human health differently.

Results: Exposure to various metals and OP was significantly associated with increased levels of various blood or urinary biomarkers. Metals and reactive oxidants in ambient particles may influence biomarker levels that reflect systemic inflammation, oxidative stress, perturbations of blood-brain barrier integrity and body stress response. These results may help interpret previously published epidemiology findings showing associations between short-term exposure to air pollution and hospitalizations and emergency room visits for cardiovascular, respiratory and neuro-psychological illness.

Publications: Liu, L., Urch, B., Szyszkowicz, M. Speck, M., Van Huang, A., Leingartner, K., Shutt, R., Pelletier, G., Gold, G.R., Brook, J.R., Pollitt, K.G., Silverman, F.S. Metals and oxidative potential in urban particulate matter influence systemic inflammatory and neural biomarkers: A controlled exposure study. Environment International. October 2018

An intervention study on the effectiveness of the AQHI advice in a panel of patients with implanted cardioverter defibrillators in Toronto

Focus of research: The AQHI is a risk communication tool intended to provide information to the public on current and forecasted air quality conditions. Although the AQHI has been used extensively for several years, little research has been done to characterize the benefits that may be achieved by following AQHI advice. The primary objective is to evaluate the actual effectiveness of the AQHI as an intervention in reducing health risks of patients wearing implantable cardioverter defibrillator (ICD). The secondary objective is to study the associations between daily exposure to outdoor O3, NO2 and PM2.5  as well as AQHI and variations in arrhythmia parameters and other cardiovascular outcomes in this panel of cardiac patients.

Results: The results suggest that air pollution was associated with adverse changes in cardiovascular measures in ICD patients. Advice to avoid exposure to outdoor air pollution based on AQHI may help reduce adverse impacts on cardiovascular measures. Daily mild exercise may benefit cardiovascular function in this cohort of ICD patients.

Publications: Liu, L., Urch, B., Nanthakumar, K., Chen, L., Smith-Doiron, M., Brook, J.R., Speck, M., Silverman, F., Stieb, D.M. Air pollution, physical activity and cardiovascular function of patients with implanted cardioverter defibrillators: A randomized controlled trial of indoor versus outdoor activity. Journal Occup. Environ. Med. (under review)

Methods to pool non-linear concentration-response models

Focus of research: New evidence is emerging that relationships between outdoor concentrations of air pollutants and health may not all be best characterized by linear risk models. This project will develop mathematical methods to combine results from several studies with non-linear associations between air pollution exposure and health.

Results: This study resulted in the development of a method pooling non-linear risk functions named the Global Exposure Mortality Model (GEMM) for non-accidental deaths. This new approach is used worldwide to determine the impact of fine PM on mortality.

Publications: Szyszkowicz, M., Thomson, E.M., Colman, I., Rowe, B.H. Ambient air pollution exposure and emergency department visits for substance abuse. PLoS ONE 13(6): e0199826.

Outdoor Pollution Exposure Risk Assessment (OPERA)

Focus of research: OPERA represents a new paradigm in how to conduct burden of disease studies to support evidence-based decision making in climate and air quality management. The project consists of 2 main components: construction of multi-pollutant concentration response functions for different health outcomes; and estimation of disease burden by source of pollution and geographic area.

Results: Improved air pollution exposure methodologies were applied to Canadian and global cohorts and found associations between air pollution exposure for a range of health outcomes including diabetes, preterm birth and mortality. A large international collaboration has made a significant contribution to the estimation of the global burden of disease associated with air pollution.

Publications: Burnett, R., Chen, H., Szyszkowicz, M., Fann, N., Hubbell, B., Pope III, A.C., Apte, J.S., Brauer, M., Cohen, A., Weichenthal, S., Coggins, J., Di, Q., Brunekreef, N., Frostad, J., Lim, S., Kan, H., Walker, K.D., Thurston, G.D., Hayes, R.B., Lim, C.C., Turner, M.C., Jerrett, M., Krewski, D., Gapstur, S.M., Diver, R.W., Ostro, B., Goldberg, D., Crouse, L.D., Martin, R.V., Peters, P., Pinault, L., Tjepkema, M., van Donkelaar, A., Villeneuve, P.J., Miller, A.B., Yin, P., Zhou, M., Wang, L., Janssen, N.A.H., Marra, M., Atkinson, R.W., Tsang, H., Thach, T.Q., Cannon, J.B., Allen, R.T., Hart, J.E., Laden, F., Cesaroni, G., Forastiere, F., Weinmayr, G., Jaensch, A., Nagel, G., Concin, H., Spadaro, J.V. Global estimates of mortality associated with long-term exposure to outdoor fine particulate matter. 2018. Proceedings of National Academy of Sciences

Stieb DM, Lavigne E, Chen L, Pinault L, Gasparrini A, Tjepkema M. Air pollution in the week prior to delivery and preterm birth in 24 Canadian cities: a time to event analysis. Environ Health. 2019 Jan 3;18(1):1. doi: 10.1186/s12940-018-0440-8

Meng, J., Martin, R.V., Li, C., van Donkelaar,A., Tzompa-Sosa, Z.A., Yue, X., Xu, J.W., Weagle, C.L., Burnett, R.T. Source Contributions to Ambient Fine Particulate Matter for Canada. Environ. Sci. & Tech. 2019, 53, 17, 10269-10278

Modification of the air pollution-lung cancer mortality relationship by synoptic-scale weather types: a Canadian national-level cohort study

Focus of research: This study examines the modifying effect of weather type on the associations between air pollution NO2, PM and O3) and human health in a Canadian national cohort, using lung cancer mortality rates and adjusting for socio-economic factors which can affect the air pollution-related risk estimate. It will also assess the relationship between local road length, proximity to primary highways, and cause-specific mortality in the 1991 Canadian Census Health and Environment Cohort (CanCHEC). The CanCHEC study comprises 2.6 million people who were enrolled in 1991 and followed-up through to 2009.

Results: The effects of long-term traffic exposure on diabetes, cerebrovascular disease, lung cancer, ischemic heart disease (IHD), and Chronic Obstructive Pulmonary Disease (COPD) mortality differ by climate zones. The results suggest that exposure to higher road density and proximity to major traffic roads was associated with increased mortality risk from cerebrovascular and cardiovascular disease, ischemic heart disease, COPD, respiratory disease, and lung cancer.

Publications: Cakmak, S., Hebbern, C., Vanos, J., Crouse, D.L., Tjepkema, M. Exposure to traffic and mortality risk in the 1991–2011 Canadian Census Health and Environment Cohort (CanCHEC). Environment International 124 (March 2019) 16-24

Benefits of kitchen exhaust fans in improving indoor air quality

Focus of research: This pilot study examines the use of different flow rate fans during cooking and tests whether continuing to run the fan after cooking significantly improves pollutant removal rates and integrated exposures.

Results: Fan flow rate and physical characteristics of the exhaust fan used during cooking were the most important determinants of exposures following cooking. This information will inform HC guidance to Canadians on reducing exposure to cooking-related air pollutants in homes.

Publications: Sun, L., Wallace, L.A., Dobbin, N.A., You, H., Kulka, R., Shin, T., St-Jean, M., Aubin, D., Singer, B.C. "Effect of venting range hood flow rate on size-resolved ultrafine particle concentrations from gas stove cooking." Aerosol Science and Technology 52.12 (2018): 1370-1381

Dobbin, N.A., Sun, L., Wallace, L.A., You, H., Kulka, R., Shin, T., St-Jean, M., Aubin, D., and Singer, B.C. "The benefit of kitchen exhaust fan use after cooking-An experimental assessment." Building and Environment 135 (2018): 286-296

Canadian Atlantic Marine Air Pollution study

Focus of research: This study investigates the impact that lower-sulphur marine fuel regulations have had on air pollution exposures for Canadians living in Halifax, Nova Scotia.

Results: Findings to date indicate that the low-sulphur marine fuel regulations have substantially reduced ambient exposures to SO2 and contributed to a moderate improvement in Halifax particulate air quality. Source apportionment modeling will be applied to quantify pre- and post-regulatory marine sector emission contributions to ambient PM2.5 and PM2.5-associated air toxics (for example, heavy metals) relative to other transport and non-transort source types.

Publications: A scientific article outlining the efficacy of the lower-sulphur marine fuel regulations will be published in 2019.

Acute and chronic health effects of ambient PM2.5 oxidative potential

Focus of research: Particulate matter oxidative potential measurements have been proposed as a promising integrated measure of overall particle toxicity. These studies investigate exposure to PM2.5 oxidative potential at different scales and apply this data to epidemiological investigations.

Results: Spatial characterization of PM2.5 oxidative potential has been conducted at the scale of both between-cities (Canada wide) and within-cities (Toronto) revealing significant distinctions from the signal observed from PM mass. Associations between oxidative potential and various health outcomes including birth outcomes have been observed. Scientific articles focusing on PM2.5 oxidative potential and development of childhood asthma and pediatric cancers will be published in 2019 with additional publications in subsequent years.

Publications: Weichenthal, S., Shekarrizfard, M., Traub, A., Kulka, R., Al-Rijleh, K., Anowar, S., Evans, G., Hatzopoulou, M. Within-City Spatial Variations in Multiple Measures of PM2.5 Oxidative Potential in Toronto, Canada. Environmental science & technology 53.5 (2019): 2799-2810.

Lavigne, É., Burnett RT., Weichenthal, S. Association of short-term exposure to fine particulate air pollution and mortality: effect modification by oxidant gases. Scientific reports 8.1 (2018): 16097

Weichenthal, S., Shekarrizfard, M., Kulka, R., Pascale, S., Lakey, S., Al-Rijleh, K., Anowar, S., Shiraiwa, M., Hatzopoulou, M. Spatial variations in the estimated production of reactive oxygen species in the epithelial lung lining fluid by iron and copper in fine particulate air pollution. Environmental Epidemiology 2.3 (2018): e020

Lavigne, É., Burnett, RT., Stieb, D.M., Evans, G.J., Godri Pollitt, K.J., Chen, H., van Rijswijk, D., Weichenthal, S. Fine particulate air pollution and adverse birth outcomes: effect modification by regional nonvolatile oxidative potential. Environmental health perspectives 126.07 (2018): 077012

Characterizing woodsmoke impacts in British Columbia (BC) communities

Focus of research: In a number of BC communities where wood burning is common, levels of PM2.5 may exceed the Canadian Ambient Air Quality Standards. Woodsmoke is believed to be a major contributor, but this has not been confirmed due to challenges in differentiating the portion of PM2.5 that originates from woodsmoke. In this study, investigators employed an innovative continuous mobile monitor to detect woodsmoke in 6 BC communities: Whistler, Pemberton, Courtney, Cumberland, Vandehoof, and Fraser Lake in the winter of 2017.

Results: The collected data is being used to develop woodsmoke concentration maps, which have been presented to the participating communities and other stakeholders. Currently the method is being refined for use by community groups.

Publications: A draft manuscript has been developed and will be submitted to a journal in 2020.

Health effects of exposure to UFPs

Focus of research: This study investigates long-term exposure to UFPs on the risk of developing lung, breast and prostate cancers using data from 3 case-control studies. As well, it investigates pregnancy exposure to UFPs on the risk of term low birth weight (< 2500 g), preterm birth and small for gestational age using a provincial birth registry in Ontario for births in the city of Toronto.

Results: Three scientific manuscripts have been published based on findings relating UFPs and prostate and breast cancer. A scientific paper on UFPs and childhood asthma was published in 2018, with additional analyses expected for 2019.

Publications: Goldberg, MS., Weichenthal, S. Labrèche, F., Lavigne, É. Number concentrations of ultrafine particles and the incidence of postmenopausal breast cancer. Environmental Epidemiology 2.1 (2018): e006

Shekarrizfard, M., Valois, M.F., Weichenthal, S., Goldberg, M., Fallah-Shorshani, M., Cavellin, L.D., Crouse, D., Parent, M.E., and Hatzopoulou, M.. Investigating the effects of multiple exposure measures to traffic-related air pollution on the risk of breast and prostate cancer. Journal of Transport & Health 11 (2018): 34-46

Lavigne, É., Donelle, J., Hatzopoulou, M., Van Ryswyk, K., van Donkelaar, A., Martin, RV., Chen, H., Stieb, DM., Gasparrini, A., Crighton, E., Yasseen, AS., Burnett, RT., Walker, M., Weichenthal, S. Spatiotemporal variations in ambient ultrafine particles and the incidence of childhood asthma. American journal of respiratory and critical care medicine 199.12 (2019): 1487-1495

Spatial modelling to support health studies

Focus of research: HC carries out intensive ambient air pollution monitoring, and develops land-use regression (LUR) models that allow for the prediction of concentrations of pollutants at a neighbourhood or household level. LUR models are being used to support local- and national-scale health studies investigating air pollution impacts on respiratory, cardiovascular (for example, stroke), developmental (for example, birth outcomes, gestational diabetes), autoimmune diseases and cancer outcomes.

Results: LUR models and other exposure data developed by HC’s Air Program are now available through several venues including The Canadian Urban Environmental Health Research Consortium (CANUE).

Publications: Brook, J.R., Setton, E.M., Seed, E., Shooshtari, M., Doiron, D. The Canadian Urban Environmental Health Research Consortium–a protocol for building a national environmental exposure data platform for integrated analyses of urban form and health. BMC public health 18.1 (2018): 114

Time-dependent vulnerability to air pollution in a pregnancy cohort

Focus of research: This study applies an emerging novel approach (multilevel Bayesian modeling) to identify periods of susceptibility to air pollution during fetal development in the Maternal-Infant Research on Environmental Chemicals (MIREC) cohort. Air pollution exposures is estimated using coupled satellite remote sensing and National Air Pollution Surveillance Program (NAPS) data, an approach that HC researchers have previously validated in Windsor, Ontario.

Results: The study results suggest that exposure to ambient air pollution during critical periods of pregnancy were associated with lower birth weight among term infants.

Publications: A manuscript is expected for submission to a journal in 2019.

Central experimental farm greenspace effects

Focus of research: Air pollution, traffic related noise and local temperatures are all influenced by features of the urban built environment. In Ottawa, the Central Experimental Farm (CEF) likely plays a prominent role in influencing these exposures, but to date there have been few efforts to evaluate these impacts. The purpose of this study was to characterize air pollution, noise and ambient temperature on and around the CEF, and to determine if the farm has a mitigating impact on these exposures.

Results: Three seasonal sampling campaigns were conducted in and around the CEF. The spatial variability of NO2, fine PM, ultra-fine particles, black carbon, volatile organic compounds, ambient temperature, and noise within this area was characterized. The study produced evidence that this large green space can mitigate levels of heat and air pollution in the surrounding area.

Publications: A manuscript was submitted to a journal for publication in 2019.

Joint effects of exposure to aeroallergens and outdoor air pollution in the urban environment

Focus of research: Little is known regarding the joint exposures of aeroallergens and air pollution among children. A LUR model approach based on environmental determinants has been developed for predicting the variability of pollen concentrations at fine spatial scales in the city of Toronto. Using the Canadian Healthy Infant Longitudinal Development (CHILD) study, the combined effects of exposure to outdoor air pollution and aeroallergens on asthma incidence among Canadian children is being evaluated.

Results: A scientific paper based on the characterization of aeroallergens in Canada was published in 2018. Results of joint effects of aeroallergens and air pollution on atopic disease development using the CHILD Study will be available in 2019.

Publications: Sierra-Heredia C., North M., Brook J., Daly C., Ellis A.K., Henderson D., Henderson S.B., Lavigne É., Takaro T.K. Aeroallergens in Canada: Distribution, public health impacts, and opportunities for prevention. International Journal of Environmental Research and Public Health 15: 8, 1577

Air quality and health impacts of freight modal shifts

Focus of research: The overall goal of this study is to identify and characterize the potential of modal shifts in freight transport for mitigating air pollutant emissions, air pollutant concentrations, population exposure to air pollutants, and health impacts.

Results: The results indicated that there is limited evidence that road-to-rail, road-to-marine, and rail-to-marine modal shifts could reduce pollutant and GHG emissions. There was insufficient evidence on modal shifts involving the pipeline mode, and on the air quality, population exposure, and health impacts related to any modal shift.

Publications: Ramani, T., Jaikumar, R., Khreis, H., Rouleau, M., Charman, N. Air Quality and Health Impacts of Freight Modal Shifts: Review and Assessment. Transportation Research Record 2673.3 (2019): 153-164

6.4 Water quality

Both ECCC and HC continued their water quality research activities.

ECCC’s research related to water quality included the following.

Method development for analytes in wastewater treatment plant influent and effluent

Focus of research: To assess changes in the levels and trends of synthetic musk compounds and OPEs in both influent and effluent wastewater in the Great Lakes Basin (musks) and across Canada (OPEs).

Results: New GC/MSMS based methods for determination of 21 nitro, polycyclic and macrocyclic musk compounds were developed. A comparison to results reported by Smyth et al. in 2008 from the same sampling sites indicated a major reduction in levels of nitro musk compounds. Levels of musk ketone have dropped by a factor of eight, while levels of musk xylene have dropped by a factor of 26 during cold sampling periods and 130 for samples collected during warm periods. Removal efficiency for musk compounds ranged between 60% and 100%. For OPEs, removal efficiencies from the liquid waste stream were > 80% in secondary and advanced treatment and as high as 60% in primary treatment.

Publications: McDonough, C.A., De Silva, A.O., Sun, C., Cabrerizo, A., Adelman, D., Soltwedel, T., Bauerfeind, E., Muir, D.C.G., Lohmann, R. 2018. Dissolved organophosphate esters and PBDEs in remote marine environments: Fram Strait depth profiles and Arctic surface water distributions. Environ. Sci. Technol. 52(11): 6208-6216

Organophosphorus flame retardants in a variety of environmental compartments

Focus of research: The goal of this project was to analyze OPE flame retardants and plasticizers in environmental samples, focusing on 23 individual OPE congeners representing alkyl-, phenyl-, and halogen- substituted OPEs.

Results: OPEs were analyzed in sediment and water from an urban, industrial environment (Hamilton Harbour) and a rural site in Georgian Bay. OPEs in sediment and water were generally lower in Georgian Bay than the Hamilton Harbour site. Furthermore, OPEs were measured in influent, effluent, and biosolids from 8 wastewater treatment plants in Canada, representing treatment technologies such as facultative lagoon, aerated lagoon, chemically assisted primary treatment, secondary activated sludge treatment and advanced biological nutrient removal. Removal efficiencies from the liquid waste stream were > 80% in secondary and advanced treatment and as high as 60% in primary treatment.

Publications: McDonough, C.A., De Silva, A.O., Sun, C., Cabrerizo, A., Adelman, D., Soltwedel, T., Bauerfeind, E., Muir, D.C.G., Lohmann, R. 2018. Dissolved organophosphate esters and PBDEs in remote marine environments: Fram Strait depth profiles and Arctic surface water distributions. Environ. Sci. Technol. 52(11): 6208-6216

Biological impacts of municipal effluents on fish in the St. Lawrence River

Focus of research: To identify the presence of emerging chemicals in fish residing in effluent-impacted waters and investigate the potential effects of these complex mixtures of the biology of fish.

Results: Fish were collected in regions of the St. Lawrence River impacted by urban effluents and the health of the animals were evaluated. Juvenile fish exposed in cages for 6 weeks to municipal effluents and contaminants have been assessed in tissues, as well as biological markers. Finally, methods have been developed to screen for chemicals of potential interest in tissues of top predator fish.

Publications: Tian, L., Verreault, J., Houde, M., Bayen, S. 2019. Suspect screening of plastic-related chemicals in northern pike (Esox lucius) from the St. Lawrence River, Canada. Environmental Pollution 255, 113223.

Lacaze, E., Gendron, A., Miller, J., Sherry, J., Colson, T.-L., Sherry, J.P., Giraudo, M., Marcogliese, D. Houde, M. 2019. Cumulative effects of municipal effluent and parasite infection in yellow perch: a field study using high-throughput RNA-sequencing. Science of the Total Environment 665:797-809

Toxicity of pesticides to non-target freshwater species

Focus of research: Neonicotinoid insecticides were assessed for their toxicity to non-target freshwater invertebrates, specifically amphipod crustaceans and mayfly larvae. The survival, growth, and behaviour of these organisms were analysed to determine the risks that neonicotinoids pose to aquatic ecosystems.

Results: Neonicotinoids caused negative effects on the survival, growth, and behaviour of freshwater species. The concentrations at which these effects were observed were within the range of environmental concentrations for some compounds, indicating that non-target aquatic species may be adversely affected by some neonicotinoids. The toxicity of neonicotinoids varied between compounds, and therefore the effects caused by one neonicotinoid cannot necessarily be extrapolated to others.

Publications: Bartlett, A.J., Hedges, A.M., Intini, K.D., Brown, L.R., Maisonneuve, F.J., Robinson, S.A., Gillis, P.L., de Solla, S.R.. 2018. Lethal and sublethal toxicity of neonicotinoid and butenolide insecticides to the mayfly, Hexagenia spp. Environ Pollut 238:63-75

Bartlett, A.J., Hedges, A.M., Intini, K.D., Brown, L.R., Maisonneuve, F.J., Robinson, S.A., Gillis, P.L., de Solla, S.R. 2019. Acute and chronic toxicity of neonicotinoid and butenolide insecticides to the freshwater amphipod, Hyalella azteca. Ecotoxicol Environ Saf 175:215-223

Environmental fate of selected human and veterinary use pharmaceuticals

Focus of research: The aquatic toxicity, bioaccumulative potential and environmental fate of selected pharmaceuticals for human and veterinary use was examined using a variety of species (bacteria, algae, yeast, invertebrates and fish) in order to derive safe concentrations for the aquatic environment.

Results: The toxicity of 20 pharmaceutical compounds likely to be released by municipal wastewaters and agriculture wastewater runoffs (manure) were examined using multitrophic biotests involving bacteria, yeast, algae, invertebrates and fish. Though the analysis is still on-going, it seems that the antibiotic products are more toxic for bacteria and algae while other pharmaceutical products having an endocrine disruption effect were more toxic to fish. Sub-lethal effects studies using the collected samples are planned in the following years.

Publications: Data shared with HC for risk assessment.

Effect of salt-laden winter road runoff on aquatic organisms

Focus of research: The effect of salt-laden winter road runoff on sensitive aquatic organisms was examined to determine if winter road runoff poses a risk to aquatic ecosystems, including freshwater mussel species at risk.

Results: Winter melt waters collected from bridges and runoff waters entering streams during a January thaw were acutely toxic to freshwater mussel larvae, most likely due to high levels of salt. However, water collected from streams receiving the melt waters was not acutely toxic to early life stage mussels. Investigations are ongoing to determine how multiple pulses of salt-laden winter runoff water affects sensitive aquatic organisms.

Publications: Conference presentation Gillis, P.L., Salerno, J., McKay, V., Bennett, C.J., Pratt, A., Rochfort, Q., Prosser, R.S. The sensitivity of freshwater mussels to salt-laden winter bridge runoff; implications for mussel species at risk. Society of Environmental Toxicology and Chemistry North America, Sacramento, CA, November 2018

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