being a major concern as a transported isotope to the Bay Area.

\[tab:volatility\]

Soil and Sediment Samples
=========================

Soil samples have been collected by LBNL personnel and analyzed at the LBF since the late 1950s. The chosen analytic technique has been gamma ray spectroscopy, first using NaI(Tl) scintillation crystal detectors, but switching to high resolution HPGe semiconductor detectors in the 1980s when they became available with relative efficiencies of at least 30%. Initially, the motivation was to document the areal distribution in surface and near-surface soils of fission product radionuclides from atmospheric nuclear weapons testing. Later applications included determination of the natural terrestrial radionuclides (U,Th,K), and determination of the radon emanation (principally the $^{238}$U series $^{222}$Rn) from these materials. Analyses continue in all of the above applications.

The current study is designed to provide information for identifying and characterizing the radionuclides transported to the Berkeley Lab from the nuclear power plant disaster at Fukushima, Japan in the aftermath of the 3/11/2011 earthquake/tsunami. Two pairs of on-site soil samples provide some relevant information, as listed in [**Table \[tab:soil\]**]{}. The first pair represents surface soils from a site near LBNL building 90 and a site near LBNL building 72, at which the 