This video provides an overview of human health risk assessments.
Concepts important to understanding human health risk assessment
There are a number of concepts and definitions used in human health risk assessment. Key definitions include ‘health hazard’, ‘health risk’ and ‘exposure’.
A hazard is something that has the potential to cause harm – it could be a biological substance, or a chemical, or something with a particular physical property, or an activity.
A hazard cannot potentially cause harm unless people or a section of the environment is exposed to that hazard.
A health hazard is therefore something that has the potential to cause harm to the health of individuals, groups of people or the broader community.
A risk is the probability (or likelihood) that a hazard will cause harm.
A health risk is therefore the probability (or likelihood) that exposure to a health hazard will cause harm.
Exposure is the amount (sometimes referred to as ‘the dose’) or concentration (ie amount of a health hazard in air, soil or water etc) in contact with or taken up into the body over a known length of time.
Human health risk assessment
Human health risk assessment is a way of assessing the potential impact of a hazard on the health of a person, group of people or a community. Factual, technical information is used to understand the potential health effects.
Each human health risk assessment is unique to the situation and population being assessed. The population in focus may be a community or specific groups within a community such as workers, children, older people or those with particular health conditions such as asthma.
The five general steps in the human health risk assessment process are:
- Issue identification: what is the identified problem or situation?
- Hazard assessment: what are the possible adverse health effects associated with the identified hazards of potential health concern?
- Understand the dose-response relationship(s): what is the dose response relationship for each identified adverse health effect? What studies are used to provide this information?
- Exposure assessment: develop a site or situation model including pathways connecting sources of each hazard to people; collect and analyse data about each hazard, e.g. assess/sample the amount in air, water or soil; identify populations that may be affected and how they may be exposed to each hazard.
- Characterise the risk: this step analyses the above information to estimate the size and nature of either past, current or future health risks for people, including communities.
Community and stakeholder consultation occur as part of the human health risk assessment process.
The human health risk assessment is important as it informs the risk management stage. This includes recommended advice or actions (if required) to ensure that human health is protected. Risk communication occurs in the risk management stage.
Human health risk assessment for environmental exposures
Environmental Health is defined as those aspects of human health determined by physical, chemical, biological and social factors in the environment. Environmental health practice covers the assessment, correction, control and prevention of environmental factors that can adversely affect health, as well as the enhancement of those aspects of the environment that can improve human health.
An environmental health risk assessment is a type of human health risk assessment that looks at the potential impacts of hazards in the environment on the health of people: - usually in defined groups or the broader community.
The Australian approach for environmental health risk assessment is described in the enHealth publication, Environmental Health Risk Assessment: - Guidelines for assessing human health risks from environmental hazards 2012, available from the Australian Department of Health .
Who does human health risk assessments?
People who do human health risk assessments generally have science, engineering or medical qualifications and usually experience relevant to the issue or situation being investigated.
Human health risk assessors work with experts in toxicology, epidemiology and chemistry, particularly when the assessment involves hazardous materials, including chemicals.
Human health risk assessors are trained to understand each step of the risk assessment process and to analyse a problem rationally. They break the assessment into smaller parts and solve each part of the issue with reason and logic, like solving a puzzle. The puzzle is then reassembled into the overall understanding of the size and nature of either past, current or future risks to human health.
Depending on the issue, government departments and agencies may undertake a human health risk assessment or engage an independent expert to do this work.
In some cases, a government department or agency may direct a person or business owner to conduct a human health risk assessment at their own cost. This may include an additional peer review process to ensure that the findings are independent and accurate.
This video provides a fictional case study of a human health risk assessment, which would likely be undertaken or directed to be undertaken by the Environment Protection Authority Victoria.
When is a human health risk assessment required?
The decision to do a human health risk assessment is made on a case by case basis, and generally when an activity or major project has the potential to affect people’s health, and to inform risk management advice and actions.
Human health risk assessment helps experts in assessing the overall situation, and in determining what advice or actions, if any, should be taken to ensure that human health is protected.
Past, current or future exposures to chemicals in air, soil, water, food, consumer products or other materials may be assessed.
Limitations of human health risk assessments
Human health risk assessment is just one tool that can be used in assessing and managing environmental health risks.
In some cases, not all information is available therefore the risk assessor may need to make calculated estimates and assumptions that are conservative. This means that to ensure public health is protected, human health risk assessments usually over-estimate the theoretical risk when there are gaps in knowledge. Environmental health risk assessments are also based on the most sensitive (or vulnerable) people in the community. This provides a ‘worst case scenario’ to inform the best possible decisions to manage human health risks.
It is important for the community to understand that human health risk assessment looks at communities or populations as a whole. A human health risk assessment highlights the nature and size of past, current or future health risks but usually does not:
- identify specific individuals who are exposed to a chemical
- compare chemical levels measured in individuals or groups of people to health outcomes
- diagnose disease – so should not replace consultation with a medical or health practitioner.
Community members who are concerned about their health or the health of someone in their care should always contact a health professional in the first instance.
For more information about the Environmental Health Standing Committee (enHealth) and the Australian approach to environmental health risk assessment, visit the
For more information about managing the impacts of pollution or waste on the environment and human health in Victoria, visit the