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 chemicalsand the levels
of those chemicalsthat 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.