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:
Doses at which harmful health effects are not expected
Based on toxicologic and epidemiologic studies
Conservative estimates with built-in safety and uncertainty factors
Used to predict adverse health effects
Based on site-specific data
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.