Step 1.4 Reviewing Background Data

Introduction and Uses

Background data describe natural levels of chemicals in the environment (such as metals in soil). Also, levels of chemicals in the environment introduced through human activity (such as pesticides from mosquito control spraying) may be considered background data. Background data are considered relative to site environmental data. Data from the site are compared with background data. The comparison indicates the chemicals—and the levels of those chemicals—that are associated with the site.

What if no site-related chemicals are found in a community, but unsafe levels of chemicals from another source are found?

Sources of data on background levels of chemicals in the environment.