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Step 1.5 Using Comparison Values

bullet Introduction

Comparison values are doses (termed health guidelines) or substance concentrations (termed environmental guidelines) set well below levels that are known or anticipated to result in adverse health effects. Comparison values are derived from scientific studies and modified by safety factors to be more protective of human health.

ATSDR's comparison values are developed for a specific chemical in each of three environmental media: air, soil, and drinking water. If a chemical is found at a level above the comparison value and people can contact the chemical, the health assessor selects the chemical for further evaluation. Also, if a chemical is found that people can contact, but there is no comparison value for that chemical, it is selected for further evaluation. Chemicals found at levels below comparison values are not selected.

Click on the headings below or on the View All link to see what comparison values are and are not.

View All


bullet Last updated: February 20, 2008 bullet ATSDR EPH Training Coordinator


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