Canada’s Impact Assessment Act aims not only to protect the physical environment but also people’s lives, when companies propose to carry out major natural resource and infrastructure projects (also called designated projects). It is meant to lessen negative project impacts, as well as boost positive project impacts, including on human health. Many factors in people’s lives contribute to their social, physical and mental well-being, one way or another, and some of these factors can be affected by a new development project. Health Canada has adapted the WHO framework on the social determinants of health to develop a generic diagram of effect pathways (above, the “adapted” framework) that shows how projects can increase or reduce health risks for nearby communities. This can help fit the project effects into the local human context and identify ways of mitigating potential bad effects and enhancing good effects.

The adapted framework illustrates the building blocks that link the project with conditions of daily life that determine health (i.e., health determinants). A project’s various components and activities include, for example, physical construction and operations, recruiting workers, and setting up living quarters for some of these workers (work camps). These activities would first have positive or negative effects on the surrounding environmental, economic, and social (including cultural) conditions, before having any human health effects. Project influences on the surrounding environmental conditions may involve the quality of the air, water, and soil as well as wildlife, plants, and landscape (e.g., linear density of roads, railways, transmission lines, pipelines). The physical environment provides the very basic necessities for life. Economic and social conditions are more complex and reflect people’s material circumstances. Under economic conditions, we have employment opportunities, work situations (e.g., shiftwork), and means for living (e.g., income, home ownership). The social conditions are how people live (e.g., education level, housing quality), feed themselves, and make use of their place of residence (e.g., green space, community infrastructure, community safety).

The material aspects of these resources, opportunities, and life situations contribute positively or negatively to community well-being (i.e., quality of life), as well as influence what health-related behaviours are likely to be taken up (e.g., eating habits, physical activity, substance use) and what biological exposures are likely to occur. All factors along the “material” pathway may ultimately have biological effects (e.g., hypertension, quality of biological processes) on physical well-being, including brain functions, and this has implications for mental well-being. In the other direction mental well-being, has implications for physical well-being through the biological stress response (e.g., hypertension, stress hormones) and associated coping mechanisms. Along the “psychosocial” pathway, some economic or social conditions found on the material pathway may have a psychological aspect to them that is either comforting (e.g., financial security, the enjoyment of the right to adequate housing) or that is stressful (e.g., mental toll of physically gruelling work conditions). Interpersonal sources of comfort or stress (e.g., community belonging and family violence) are also psychosocial factors linked to mental well-being. As well, the beneficial psychosocial effects of cultural practices (including use of traditional lands and waters) are critical for the mental well-being of Indigenous Peoples, which encompasses emotional and spiritual wellness.

Cumulative effects on the physical and living environments (at the community level) arising from a variety of past, present and future resource-development activities of varying scale may have net positive or adverse health impacts. That being said, it is difficult to make a definitive link between any single determinant of health and health outcomes, at the individual level. However, best practices can be used to manage project-specific influences on host communities (e.g., environmental safeguards, communication plans, road safety measures, community investments, wellness programs) and minimize health risks concerning physical and mental health (including infections), as well as injuries and physical harms.