EXTOXNET FAQs - Adverse Health RisksAdverse Health Risks

What Risks are Involved? Do I run the Risk of Getting Sick or Cancer? What's the risk from pesticides? Is my health at danger or risk from chemicals? These are all very good questions because virtually every activity we participate in involves risk....from the moment we smear antiperspirant on in the morning to drinking that morning brew to driving to work and back again. We read the labels in the grocery stores, scanning for fat or artificial additives. We regulate our coffee intake and the speed we drive. There are many types of health risks that we unconciously weigh every day.

We come into contact with many substances, many unknowingly. Some may have the potential to cause adverse health effects, but how do we know if we are at risk of becoming ill from exposure to these substances?

Health Risk Assessment (HRA) is the method used to determine the magnitude and probability of an adverse health effect from exposure to a substance. The HRA is the basis from which we set regulatory standards for safe levels of exposure to chemicals in our environment. It is a process consisting of four elements.

In order to determine whether there is an actual threat to our health from a contaminant the risk assessor must identify the substance of concern and evaluate its inherent toxicity. This is called HAZARD IDENTIFICATION.

Another component is an assessment of the response of living organisms at various doses of the substance. At what dose will we see effects? At what dose will we see no effects? This step is called DOSE/RESPONSE ASSESSMENT.

The assessor must also determine the levels of exposure that are actually occuring within the population of concern. The various routes of exposure and how much is actually getting into the body must be considered. This is called EXPOSURE ASSESSMENT.

The information from these three areas are then compiled in order to characterize the magnitude and probability of an adverse health effect on the population being exposed. This is RISK CHARACTERIZATION.

Risk Assesment Links:

The Institute for Environmental Toxicology - Risk Assesment

The Institute of Environmental Toxicology - Concepts and Information - Please see the overview of risk assessment section.


This page was prepared by Theresa L. Pedersen, UCD EXTOXNET FAQ Team. September, 1997. I would like to thank Nu-may Ruby Reed, PhD for allowing me to draw freely from her lectures on Health Risk Assessment, which are the backbone of this page. Her lectures were conducted at the University of California, Davis in the fall quarter of 1996. Thanks again Ruby!