surfaces had not been disturbed since before the onset of atmospheric nuclear weapons testing that began in the mid-1940s. The second pair were sampled in late April 2011; one from the undisturbed site near LBNL building 90, and the other from the face of a shallow cut in deeply weathered Orinda Formation bedrock along one side of the parking lot at building 72, wherein the present surface has only been exposed since the late 1970s during a major expansion of the building.

The absence of $^{134}$Cs in the 1998 samples identifies the activity of $^{137}$Cs remaining from mid 20$^{th}$ century atmospheric nuclear weapons tests. The results presented in the air monitoring results of this report indicate approximately equal activities of $^{134}$Cs and $^{137}$Cs were deposited at our sampling sites; hence the $^{134}$Cs activities observed in these April 2011 samples allows estimates to be made for the $^{137}$Cs activities delivered from the Fukushima accident.

A number of sediment samples obtained from laboratory roads were also analyzed. The asphalt road connecting building 72 with the main part of LBNL extends almost horizontally across a steep hillside. An asphalt berm (curb) along the downslope edge of the road protects the slopes below from 