Where are the comparisons to pre-Fukushima levels?
Lots of people are pointing to these numbers as indications that levels of these isotopes in Berkeley have increased since Fukushima. But I haven't seen any evidence that this is so, since there are no pre-Fukushima measurements. I think you should add a section discussing what you know or don't know about how these levels have changed since the accident.
It is true we do not have
It is true we do not have levels before the event because we did not start monitoring until the event occurred. However, I131, Cs137, and Te132 are not naturally found in the environment in California. We are making an assumption that these isotopes would be below our minimum detectable activity limits before the event. Since levels are now returning to below our MDA, this seems a good assumption.