Laboratory analytical data are reported in concentrations of measured quantities per amount of soil or water. A kilogram of soil or a liter of water is 2.2 pounds. Ppm and ppb are concentrations. These units are commonly seen in PRS organic and inorganic characterization results used to precisely define the extent and magnitude of contamination. Thus, the response of the detector can be associated with certainty to the concentration of the standard and the response can be extrapolated to express intermediate concentrations.
Standards are known concentrations of a contaminant or chemical substance.
They are used to calibrate detectors or analytical equipment so that reliable sample results may be obtained. Radiation concentrations are expressed in unique terms. The important criterion is the amount of radiation emitted by the radionuclide. The number of atoms of a nuclide in a gram is dependent on its atomic weight. The physical standard unit is the Curie.