Everyday Toxicology – Exposure-based Risk Assessment
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EmailRegulators, researchers, and manufacturers use risk assessments to determine ingredient and product safety. In this post, we look at how exposure-based risk assessment works to ensure the safety of the ingredients in the products we're exposed to.
What is Exposure-based Risk Assessment??
Exposure-based risk assessment is a scientific process used to determine the safety of an ingredient by evaluating the potential risks associated with its exposure. This involves several steps: 
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Hazard Identification: Identifying if an ingredient can cause harm.
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Dose-Response Assessment: Determining the relationship between the amount of exposure and the health effects.
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Exposure Assessment: Measuring how much, how often, and how long people are exposed to the ingredient.
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Risk Characterization: Estimating the likelihood of adverse health effects based on the previous steps.
Why is hazard identification important?
Hazard identification is the first step in exposure-based risk assessment. It involves recognizing if an ingredient or substance can cause harm. Certain chemicals might be hazardous because they can potentially cause adverse health effects in specific situations or doses.
For example, water is a hazard because if we exceed our body's ability to process and excrete it, the excessive water can dilute the sodium levels in the blood, leading to an electrolyte imbalance. However, when consumed in normal quantities, it keeps us hydrated and allows our body to function properly.
How does a dose-response assessment work?
A dose-response assessment examines the relationship between the amount of exposure (dose) and the resulting health effects. This step helps determine the levels at which a substance can cause harm.
For instance, like in our water example, consuming water in normal quantities is beneficial to our health, but an excessive dose can be dangerous. By studying these relationships, we can establish safe exposure levels.
What is an exposure assessment?
Exposure assessment measures how much, how often, and how long people are exposed to a particular substance. It considers various factors, including the exposure route, quantity, frequency, and duration of exposure.
For example, when evaluating a food additive, scientists assess how much and how often people typically consume the additive. This helps us understand the real-world exposure levels.
How is risk characterized?
Risk characterization combines information from hazard identification, dose-response assessment, and exposure assessment to estimate the likelihood of adverse health effects. This step answers the question: "What is the risk?"
It provides a comprehensive picture of the potential health impact of a substance based on the identified hazards and the assessed exposure levels.
Does the exposure route matter when looking at risk characterization?
Exposure routes matter because they change how regulators, researchers, and manufacturers determine safety.
Let's look at the different ways exposure route matters when characterizing risk.
Ingestion: ingested ingredients include anything we consume, such as food and beverages. The risk assessment for these products ensures that the amount of novel or additive ingredients (like artificial sweeteners) remains within safe consumption limits.
Regulatory bodies like the U.S. FDA set these limits based on extensive studies and conservative safety margins to protect vulnerable populations like children.
Dermal: for products designed for the skin, like cosmetics, we must consider the duration of use, the size of the exposed skin area, and the application frequency. For example, a daily moisturizer on the entire body poses a different exposure risk than a spot treatment applied occasionally to a small area. This step helps in understanding the actual exposure levels consumers face.
While the U.S. FDA regulates cosmetic ingredients, it doesn't have the same requirements for ingested or internal use ingredients unless a cosmetic makes a medical claim (e.g., treats acne).
Internal: Products for internal use, such as tampons, come into direct contact with internal body tissues. This kind of exposure to mucous membranes requires manufacturers to assess the safety of the individual ingredients and, ultimately, the final product to ensure safety.
In the U.S., the FDA regulates these products as a medical device, and manufacturers must meet or exceed current safety standards.
Why do exposure-based risk assessments matter?
Risk assessments provide a scientific basis for determining safe use levels for ingredients in various products.
By analyzing data from studies, clinical trials, and real-world exposures, regulatory agencies can set guidelines that protect even the most vulnerable populations, such as children and pregnant people. This ensures that all consumers can safely use products without adverse health effects.
Where can I learn more about assessing risk and safety?
Determining safety and understanding risk is multifaceted. Here are some additional posts that provide more context to the risk assessment and safety process:
The good news.
By understanding exposure-based risk assessment, we can weigh the risks and benefits of the products we use in our daily lives, avoiding unnecessary fear and making choices that support our well-being.
If you have any questions about foods and ingredients, please reach out to us via email or submit your idea to us at go.msu.edu/cris-idea.
