Thursday, September 15, 2011

[Preliminary Alert] The 9/14/11 Rainfall Shows Indications of Longer Half Life Radionuclides

UPDATE:  The sample continues to be radioactive and has a calculated half life of 2.4 days.  See the MAXIMUM ALERT for additional information

[MAXIMUM ALERT] Neptunium 239 Potentially Detected In Saint Louis 9/14/11 Radioactive Rainfall

Original Post below

This is a PRELIMINARY ALERT to take extra precautions with items that may have come in contact with the 9/14/11 radioactive rainfall in Saint Louis Missouri. see
[ALERT] Saint Louis Fallout 133x Greater Than Background Radiation 1.333 mR/hr

The Longer Half-Life alert may change to a false detection (or full blown alert) based on further testing to establish if changes have occurred in instantaneous background measurements.

The Preliminary alert is based on the detection of longer half life radionuclides in the fallout. As of 2:33pm STL time, the 1.33 mR/hr fallout is still reading approximately 0.014 mR/hr. The sample has been holding that value since approximately 11:30pm last night. The reading is comprised only of Beta and Gamma radiation, as all Alpha radiation is being shielded by the ziploc bag containing the sample.

The current value was established with two 10 minute total counts of 475 and 478 counts per min, taken at roughly 1 hour intervals.   The normal background levels for a  10 minute total test is typically 0.0077 mR/hr; current readings from the sample are therefore 2x background. This is an unusual situation, hence the preliminary alert. Further testing will occur to establish if this high reading is from the test sample or some other on going background anomaly.


  1. Hi there, looks like you catch some nice sample of Radon 222 decay radio elements like Bi214 (half-life 20 min) and Lead-214 (half-life 27 min).

    20 hours after initial sampling, you should have roughly 1/100 of initial activity for a mix of Le/Bi (1/(2*20*2.5))and your second reading of 0.013 mR/h seems to fit nicely for that.

    Not Fukushima but helpful to understand.