Sr-90 in water bodies

[Gary Schroeder <schroede@mail.sep.bnl.gov>]

Greetings.  Here at Brookhaven, we have been under intense public scrutiny
regarding the results that have been published in recent years in our Site
Environmental Report; in particular, our radiation measurements, of course.
The current hot topic involves charges made about radioactivity in the
Peconic River, essentially a small stream on site which becomes larger
farther downstream.  

We have analyzed water from this river for all radiological parameters
including strontium-90 on a routine basis, both on-site and several miles
downstream.  We have observed positive results both in the river and at a
background "control" location SW of the Lab, albeit at levels close to our
detection limit.  The levels observed in the river samples and the control
samples are essentially equal.  However, we're concerned that despite this,
certain groups who have an axe to grind will credit Brookhaven with
"contaminating" the control location as well.  
What I'm searching for is a reference which quotes measured values in water
bodies nowhere near nuclear facilities (I have plenty of data for rivers
around power plants and the like).  I need something which shows that indeed
Sr-90 can be seen in environmental water samples in the tenths of a pCi/L
range.  Can 60's weapons fallout account for this?

All responses appreciated, please respond  _directly_  to
schroede@mail.sep.bnl.gov.  (Any similar info on Cs-137 in water would also
be nice.)
===============
Gary L. Schroeder
Brookhaven National Laboratory
schroede@mail.sep.bnl.gov