The Integrated Chemical Mixtures Project

In 2023, Environment and Climate Change Canada (ECCC) launched the Integrated Chemical Mixtures Project (ICMP). The Integrated Chemical Mixtures Project aims to develop an approach to increase our understanding of the effects from real-world chemical mixtures that may be present in the environment. New information generated will support the protection of the environment and human health from harmful chemical substances.

Researchers from ECCC and universities collect samples in:

• air
• water
• soil
• sediment
• wastewater
• wildlife (eggs and in some cases tissues)
• other biota (mussels, snails, earthworms)

Researchers analyze samples to determine what chemical mixtures they contain. They evaluate the effects of these chemical mixtures on the environment, including wildlife and biota. Depending on the findings, actions to decrease impacts may be identified.

The ICMP team collaborates with:

• local partners, including civil society organizations
• First Nations communities
• industry
• other federal departments and provincial/municipal governments
• conservation authorities

This first phase of the project takes place in Southern Ontario:

• in the Brantford area, and along the Grand River
• in the Sarnia area and along the St. Clair River

Background

Through the Chemicals Management Plan, the Government of Canada assesses and manages risks to human health and the environment posed by substances, including chemicals.

However, combinations, or mixtures of chemicals, known and unknown, are present in the environment. Mixtures are defined as 2 or more chemicals in which each substance keeps its own chemical identity and properties. Chemical mixtures can be found in air, water, soil, sediment, wildlife, and other biota. Several human activities may contribute to chemicals being released in the environment, including urban development, agriculture, and industrial activities.

Project objective

The Integrated Chemical Mixtures Project provides detailed studies on the compositions and effects of chemical mixtures. The information generated will help activities to protect the environment from chemical mixtures. The project contributes to the implementation of the right to a healthy environment under the Canadian Environmental Protection Act, 1999.

Project scope

• Study the presence and effects of chemical mixtures in multiple environmental media:
  • Air
  • Water
  • Soil
  • Wildlife
  • Other biota
• Develop methods to determine how human activities contribute to effects of chemical mixtures in the environment
• Work in partnership with communities and other stakeholders
• Develop an approach to study and characterize effects on the environment, and manage real-world chemical mixtures

A project list is available below. Findings from ICMP research projects will typically be published in peer-reviewed journals (open access, where possible) upon project completion.

ICMP sampling sites

The ICMP is focusing its activities on the Sarnia and Brantford regions for this initial pilot phase and may be expanded to other regions in the future. The Sarnia and Brantford regions were chosen, in part, based on community concerns and interest in participating. Chemical mixtures can be found everywhere. These 2 regions offer an opportunity to develop a proof of concept and to engage with impacted Indigenous communities, industries, municipalities, and provincial partners.

Contribution agreements

ICMP has established funding agreements with external collaborators to financially support their projects related to chemical mixtures. Project titles and funding recipients are listed further down.

Contact us

By email: PIMPC-ICMP@ec.gc.ca

Or contact us via the Substances Management Information Line.

Project list

1. Per-and polyfluoroalkyl substances (PFAS) in exposed European starlings and effects in Brantford
   • Project description: PFAS present in the Brantford area end up in the Grand River. They accumulate up food chains to birds including the terrestrial food chain and to European starlings. We will study PFAS exposure, reproductive and other impacts and effects in birds and eggs from the Brantford area and reference sites.
   • Publications and references: Chu, S.G., de Solla, S.R., Smythe, T.A., Eng, M., Lavoie, R., Letcher, R.J. (corresponding author). 2025. Poly- and per-fluoroalkyl substance profile revealed by targeted and non-targeted screening in European starling eggs from multiple nesting sites across Canada. Environmental Pollution 376, 126414.
2. PFAS in exposed tree swallows and effects in Brantford
   • Project description: Tree swallows from Brantford and reference sites will be studied for PFAS and chemical mixtures, and reproductive impacts and other effects in exposed birds. Tree swallows feed within a 250 m zone around their nest boxes and help us understand if they accumulate legacy, new and emerging PFAS pollutants. These chemicals enter the environment through landfills, wastewater treatment plants, and by aerial deposition. The swallows also help to identify any endocrine, physiological, or reproductive changes that may be associated with the birds accumulating these pollutants.
3. Targeted and non-targeted PFAS in 3 sentinel birds having differing diets in Brantford and reference nesting sites
   • Project description: Tree swallows, European starlings, and herring gulls nest in or close to the Brantford region. Each bird eats different prey. Swallows eat bugs from the water and grassy areas as they fly over water and fields. Starlings only eat bugs that come from the land. Herring gulls eat a bit of anything whenever they can find it. These birds build-up PFAS over time in their bodies and transfer them to their eggs. However, most analysis methods only measure 20-30 out of the over 10 000s of PFAS chemicals. To find these other PFAS, we are using "non-targeted analysis" methods.
4. Atmospheric deposition reflects a gradient of air/water pollution and exposure to northern leopard frog embryos
   • Project description: Air pollutants can be trapped by snow and released into ponds and rivers as the snow melts. We will study if eggs from spring breeding frogs are harmed by these snowmelt-released air pollutants in the Brantford and Sarnia areas.
5. Chemical mixtures and characterizing specific toxic constituents and microbial indicators of landfill leachate composition in the Brantford region
   • Project description: We are studying chemicals and microbes within contaminated water (leachate) collected from the Brantford landfill. This information will help us:
     • find microbes that can tolerate harmful chemicals for future cost-effective environmental screening tools
     • identify microbes that can clean up these contaminants
6. PFAS and chemical mixtures in biosolids, soils and relevant biota in Brantford
   • Project description: We are interested in soil health, that is, whether contaminants from biosolids can affect or be taken up by plants and soil organisms (such as earthworms) when biosolids are applied to soil. We hope to find out if this poses a risk to other animals (for example, birds) through trophic transfer. We are also looking at whether different soil types influence the bioavailability and potential transfer of contaminants to plants and soil organisms.
7. An integrated multi-endpoint assay to measure the dose-response to PFAS mixture extracts in an animal alternative aquatic toxicity model: Zebrafish
   • Project description: We will use an integrated multi-endpoint assay to measure the dose-response to PFAS mixture extracts in an animal alternative aquatic toxicity model: the zebrafish embryo. Endpoints will include:
     • acute toxicity (mortality and deformities)
     • metabolism
     • swim behaviour and
     • gene expression

A variety of statistical analyses will be used to compare the mixture components (PFAS and non-targeted analysis profiles) to any observed toxicological effects.

8. Chemical mixtures in air affecting tree swallow health and threatening biodiversity in Brantford (co-location of Polyurethane foam-passive air samplers with tree swallows bird nest study)
   • Project description: Air samples were collected from Brantford in the vicinity of Tree swallow birds’ nests and landfill area. We will analyze these samples for pollutants such as fluorinated chemicals to understand the exposure to these pollutants due to inhalation from air.
9. Linking chemical mixtures in air to indicators of health in Sarnia
   • Project description: Air samples are being collected from many different locations in Sarnia. We will test these for different types of chemicals and assess if they are potentially harmful to the environment and human health.
10. Revealing the presence and importance of transformation products in the atmosphere of Sarnia and Brantford
    • Project description: We will analyze air samples collected from Sarnia and Brantford for the presence of transformation products. Transformation products to study will be assigned based on results from laboratory oxidation experiments. These experiments will target a range of chemicals relevant to Brantford and Sarnia. Ambient air samples will be subjected to toxicity analysis as well as inflammation studies on human cells.
11. Assessing the influence of atmospheric deposition mixtures in Sarnia and Brantford on wildlife and linkages to human health
    • Project description: We will collect air and snow/rain samples in Sarnia and Brantford to investigate what chemicals can enter the ecosystem from the air. We will also assess their environmental and biological impacts in the 2 regions.
12. Integrating and visualizing multi-pollutant mixture data
    • Project description: We are working on improving data visualization when dealing with complex environmental mixtures.
13. Target and non-target analyses of complex mixtures in Brantford and Sarnia to support effects assessments, source identification and abatement evaluations
    • Project description: The objectives of this work will be to:
      • Support effects-based field/lab studies on the mixtures (landfill leachates)
      • Establish baseline knowledge of mixture compositions (landfill leachates) where effects are observed, with increasing effort directed by priorities. Develop workflows for known and unknown substances
      • Establish chemical fingerprint of landfill leachates for potential groundwater studies
14. Non-targeted analysis to identify unknown chemicals (industrial congeners, toxins, pesticides, pharmaceuticals) and their transformation products
    • Project description: We are developing methods to identify unknown contaminants in wastewaters and landfill leachates. We intend to identify the more complex contaminants like the chemicals transformed after their release and industrial chemicals. We also look at agricultural sources of algal toxins and pesticides to determine if there is a synergic effect of mixtures.
15. Assessing the impact of complex mixtures in the Grand River on wild fish health
    • Project description: Investigation to assess the health of fish along a gradient of the Grand River adjacent to the city of Brantford’s wastewater facility outfall. We apply the Environmental Effects Monitoring Adult Fish survey approach by collecting benthic and pelagic fish. We evaluate then for:
      • health indicators of metabolism
      • energy storage
      • reproductive development
      • age
16. Assessing the aquatic biodiversity along an urban gradient using the New Approach Method Environmental DNA
    • Project description: We are assessing the biodiversity of the aquatic community in surface water samples using environmental DNA of:
      • microbes
      • phytoplankton
      • zooplankton
      • mussels
      • fish

    Samples in the Grand River were collected along the urban gradient adjacent to the City of Brantford and major agricultural tributaries of the Grand River.

17. Assessing the effect of mixtures in native fish using fish embryos
    • Project description: We will assess the response of fish eggs and larvae to toxicants using a fish embryo (sensitive life stage) toxicity test. This test is an animal-free testing alternative New Approachs Method. Measured responses include:
      • embryo hatching success
      • malformations
      • survival
      • and gene expression
18. Assessing the impacts of urban and agricultural activities on the Grand River and its tributaries near Brantford, using laboratory and in situ exposures with freshwater invertebrates
    • Project description: We are assessing the health of Brantford rivers by exposing invertebrates to stream water in the lab and field. We are using 2 native Ontario species that are important as food for fish, amphibians, and waterfowl.
19. Investigating the effects of complex mixtures on freshwater mussels, including species at risk
    • Project description: We are examining the effects of complex chemical mixtures on wild freshwater mussels. We do so by assessing the abundance and richness of mussel populations in the Brantford area. In addition, we are testing in the laboratory how mussel larvae, the most sensitive life stage, respond to field-collected waters from those same sites. We do the same for samples of municipal wastewater effluents and landfill leachates in the laboratory.
20. Assessing the impacts of anthropogenic activities in Brantford and Sarnia to freshwater gastropods
    • Project description: This study investigates the toxicity of surface water samples on the development and hatching of snail embryos and adult snails caged in the field. We will seek to identify mechanisms of action and biological pathways impacted using a metabolomic approach. We will evaluate the impacts of anthropogenic activities on freshwater snail communities.
21. Chemical mixtures in people living in Brantford, Ontario
    • Project description: Biological samples such as blood and urine were collected from people living in Brantford, Ontario as part of the 2009-2011 and 2012-2013 Canadian Health Measures Survey (CHMS). These samples were stored in the Statistics Canada Biobank. We are now measuring over 40 environmental chemicals in these samples, including metals, flame retardants, and pesticides. We will explore the levels of environmental chemicals to better understand exposures to chemical mixtures in people living in Brantford.

External projects funded through contributions

Investigating the use of sub-lethal endpoints to identify the potential effect of complex mixtures on freshwater biota
University of Guelph, Prof. Ryan Prosser
Ryan Prosser | School of Environmental Sciences (English only)

Toxicity estimation methods for assessing toxicity of transformation products in air
York University, Prof. Ali Abdul-Sater
Faculty of Health (English only) Home - Abdul-Sater Lab (English only)

Characterizing targeted and non-targeted PFAS mixtures in a mid-trophic passerine, the tree swallow, and its aquatic-terrestrial food web
McMaster University, Prof. Emily Choy
Emily Choy - McMaster Experts (English only)

Assessing influence of atmospheric deposition mixtures in Sarnia and Brantford on wildlife and linkages to human health
University of Toronto, Prof. Hui Peng
Hui Peng | Department of Chemistry (English only)

Environment justice analysis of contaminant mixture data
University of Toronto, Prof. Matthew Adams
Matthew Adams | Department of Geography, Geomatics and Environment (English only)

Development and optimization of methods to assess oxidative potential of air mixtures from source sectors in Canada
Trent University, Prof. Mark Parnis
Mark Parnis - Chemistry - Trent University (English only)

Development of methods to represent ambient levels and cumulative impacts of air pollutant mixtures
University of British-Columbia, Prof. Amanda Giang
Amanda Giang - Institute for Resources, Environment and Sustainability (English only)

Knowledge mobilization towards Indigenous-led pollution policy, regulation, and action
Environmental Defence Canada inc.
Home - Environmental Defence (English only)

Making sense of monitoring data to improve risk assessment and management of complex chemical mixtures
RWTH Aachen University, Prof. Thomas Backhaus
Prof. Backhaus | Department of Biology | RWTH Aachen University (English only)

New quantitative non-targeted analysis approach
Recipient: Université de Sherbrooke, Prof. Pedro Alejandro Segura
Link: Pedro Alejandro Segura - Département de chimie - Université de Sherbrooke (French only)

Moving toward an integrated assessment of complex chemical mixtures in watersheds
University of Waterloo, Prof. Mark Servos
Mark Servos | Biology | University of Waterloo (English only)

WATCH engagement and citizen-science education
Wallaceburg advisory team for a cleaner habitat
WATCH (English only)

Studying chemical mixtures in the Walpole Island First Nation environment
Walpole Island First Nation
Heritage Centre - Walpole Island First Nation (English only)