R. W. Hanf
The following information is provided to assist the reader in understanding the report. Definitions of
technical terms can be found in Appendix B, "Glossary." A public information summary pamphlet is
available by following the directions in the "Preface."
Scientific Notation
Scientific notation is used in this report to express very large or very small numbers. For example, the
number 1 billion could be written as 1,000,000,000 or using scientific notation as 
. Translating from
scientific notation to a more traditional number requires moving the decimal point either left or right from the
number. If the value given is 
, the decimal point should be moved three numbers (insert zeros if no
numbers are given) to the right of its present location. The number would then read 2,000. If the value given
is 
, the decimal point should be moved five numbers to the left of its present location. The result
would become 0.00002.
Metric Units
The primary units used in this report are metric. Table H.1 summarizes and defines the terms and
corresponding symbols (metric and nonmetric) found throughout this report. A conversion table is given at
the end of this section.
Radioactivity Units
Much of this report deals with levels of radioactivity in various environmental media. Radioactivity in this
report is usually discussed in units of curies (Ci) (Table H.2). The curie is the basic unit used to describe the
amount of radioactivity present, and concentrations are generally expressed in terms of fractions of curies per
unit mass or volume. One curie is equivalent to 37 billion disintegrations per second or is a quantity of any
radionuclide that decays at the rate of 37 billion disintegrations per second. Disintegrations generally produce
spontaneous emissions of alpha or beta particles, gamma radiation, or combinations of these. In some
instances in this report, radiation values are expressed with two sets of units. One set of units is usually
included in parenthesis or footnotes. These units belong to the International System of Units (SI), and their
inclusion in this report is mandated by DOE. SI units are the internationally accepted units and will
eventually be the standard for reporting radioactivity and radiation dose in the United States. The basic unit
for discussing radioactivity, the curie, can be converted to the equivalent SI unit, the becquerel (Bq), by
multiplying the number of curies by 
. One becquerel is equivalent to one nuclear disintegration per
second.
Radiation Dose Units
The amount of radiation received by a living organism is expressed in terms of radiation dose. Radiation dose
in this report is usually written in terms of effective dose equivalent and reported numerically in units of rem
or in the SI unit, sievert (Sv) (Table H.3). Rem (sievert) is a term that relates ionizing radiation and biological
effect or risk. A dose of 1 millirem has a biological effect similar to the dose received from about a 1-day's
exposure to natural background radiation (see "Hanford Public Radiation Dose in Perspective" in Section 6.0
for a more in-depth discussion of risk comparisons). To convert the most commonly used dose term in this
report, the millirem, to the SI equivalent, the millisievert, multiply millirem by 0.01.
Additional information on radiation and dose terminology can be found in the glossary of this report
(Appendix B). A list of the radionuclides discussed in this report and their half-lives is included in Table
H.4.
More