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Step 2.2 Comparing Exposure Doses to Health Guidelines (Observed Effect Levels)


After the site-specific exposure doses have been estimated, they are compared to human health guidelines, such as ATSDR’s minimal risk levels (MRLs). If the estimated dose for a chemical is at or above the health guideline, then the exposure will be further evaluated.

Click on the headings below  to see information about health guidelines as used in the assessment of noncancer effects:

Health guidelines are

checkmark Doses at which harmful health effects are not expected

checkmark Based on toxicologic and epidemiologic studies

checkmark Conservative estimates with built-in safety and uncertainty factors

Health guidelines are not

cross mark Used to predict adverse health effects

cross mark Based on site-specific data

cross mark Clean-up levels

What is the difference between an environmental guideline and a health guideline?

An environmental guideline or comparison value is a level (concentration) of a chemical in air, soil, or water that is considered safe for human contact. A health guideline is the dose (amount) of the chemical entering the human body that is not expected to cause harm.