which brings us full circle- any found is a pollution indicator. the world is polluted by nuclear technology- fall out from weapons is readily detected in game and hunters, chernobly spread a nice wide band over the southern US, SNAP reactor and Russian reactor burn up in the atmosphere makes plut some what easy to find. Now, what is the risk.. that is the question that should be asked. 25 mr/yr is a good number, 10 mr/yr is politically correct. nuff said?
This is an interesting hang-up of yours, pollution. Using Webster's New Third International Dictionary, one finds the #1 definition as "emission of semen than at other times than in coition." An interesting picture that you paint. However, since radiation has been present on the face of the planet for as long as you care to measure, I am unsure of the relationship.
But I digress, this doesn't bring us full circle. Maybe it brings us full spiral. This thread intitiated a discussion designed to elicit discussion of releases of areas based on nuclide data. That goal has not been gained. I, personally, have lost interest in the thread as it has run away off course. However, since there are so many who like this thread I am in favor of it's maintenance for the conversation and postings that have been and will be done. However, please do not hijack this as another subject. If you wish to start a thread on nuclear "pollution" I am sure that others will be willing to go to it.
RE: the issue of "negative dpm", this is a moot point. When performing a survey that will be recorded as permanent, i.e. a Final Status Survey, do it in a manner that is statistically, technically, and politically correct. Do not convert your data to dpm. Record it as cpm along with the other pertinent items needed for the conversion such as meter/probe type, serial numbers, CDD, BKG, etc. In this manner you will remove yourself from a possible discussion of this nature. Anyone who wishes the dpm value can simply do the conversion themselves and, if they have your data in an easily manipulated program such as Excel, will be able to do it quicker and more accurately than you are able while in the field. Besides, dpm is such a bogus venue. Maintaining the data in curies (pCi for the lower ranges of contamination) is much more sensible as you are able to calculate different radiological scenarios rapidly such as; going from surface contamination to potential airborne contamination during different work levels, taking liquid concentrations and figuring out what's on the floor and in the air after you dump the drum, anticipating the dose rate in a room based on the concentration in the tank, etc. Ooops, there I go, falling into the digression ditch again. Leave the data in counts.