My cores were sampled from marshes within the tidal portion of the Potomac River and marshes near the confluences of its tributaries. The Potomac is tidal to just west of Washington, DC and that is the freshwater tidal zone. Dyke Marsh is my freshwater site location and is located just south of DC and the Woodrow Wilson Bridge. I have two sites within the oligohaline zone (slightly salty) that extends from Quantico to the 301 Bridge in Dalhgren, and my remaining two locations are within the mesohaline zone which extends to the mouth of the river into Chesapeake Bay.
Christopher (isoenzyme) offered to test several of my samples to see if the cesium-137 peaks could be detected with my limited sample size. Each of my subsamples available to test will only be about 2g dried due to the high organic matter (cores are from mostly cattail marshes). Excitingly, he was able to get data on the three samples with his CsI(Tl) standup setup. So, CsI(Tl) is the crystal route we want to go- because we know it is sensitive enough to measure the low levels present within our samples.
Thank you for the info about NaI(Tl) crystals. Let me know if you have any more questions about my research and I'll keep you all updated with my progress.
Addison.G wrote: ↑17 May 2019, 12:56Liz,
That research sounds very interesting, where along the river are the cores taken from? I recall seeing though that NaI(Tl) looses linearity below 100kev which may be an issue. That could be specifically calibrated for, but you might need two separate calibrations for 137Cs and 210Pb.