Plain Language Explanation of Human Health Risk Assessment

Many factors can affect a person’s health, such as quality of life, how long they live, and whether or not they suffer diseases. These factors are referred to as determinants of health. The quality of environmental media related to oil sands developments in northeastern Alberta represents a concern to people at the local, national, and international level. The key determinants of people’s exposure to chemical pollutants are: time-activity (where we spend time and what we do), interaction with indoor environments, diet, and occupation. In most instances these determinants explain most or all of what influences exposure to chemicals in the environment. One way to investigate the relationship between the quality of environmental media and human health risk is to perform a human health risk assessment (HHRA). A human health risk assessment is an important component of most environmental impact assessments of new oil sands development projects. Human health risk assessment is also likely to be a key requirement for understanding potential human health impacts of the release of oil sands process affected waters to the environment. A human health risk assessment is the process of determining if a particular chemical or other hazard in the environment (e.g., particulate matter) poses a health risk to people for a specific set of conditions. People are called receptors in human health risk assessment. It is not possible to tell where in time and space people will actually be in relation to where chemical pollution exists, and therefore the extent to which they are actually exposed. Thus assumptions need to be made about their exposures to allow us to assess human health risk. Human health risk assessments are prepared by professional consultants (scientists and engineers) for government, industry and other organizations. This is done to help decision makers, especially policy makers and regulators, understand potential health impacts from the release of chemical pollutants into the environment by industrial operations. This type of information – along with social, economic, and other information – can help to inform policy and regulatory decisions that help protect people from chemical exposures as a result of pollution. Human health risk assessment procedures described here are normally accepted by regulatory agencies because they are, purposely, conservative. This conservatism makes it less likely to under estimate potential exposures and human risk and more likely that resulting regulatory decisions made will protect people from chemical pollution by industrial operations in real situations.