by Dan Sythe / / January 4, 2014 /

A lot of concern has been expressed about recent reports and videos showing high levels of radiation on a beach in Half Moon Bay, just South of Pillar Point Harbor.  It has been attributed  to Fukushima.  Local officials have been quoted as saying they donʻt know what it is, but donʻt worry about it.  See local story.

Here is what we have learned so far:   The radioactive areas of the beach seem to be associated with dark sand below the high tide level.   The levels detected are about 5 to 10 times what you would normally expect to find on a beach.

The radionuclides are in the NORM class of radioactive substances, not from Fukushima. NORM stands for Naturally Occurring Radioactive Material.   We put a sample in a Multichannel Analyzer and found Radium 226 and Thorium 232.  See the measured spectra below.

This is the spectra from the beach sample

This is the spectra from the beach sample

If the sand were contaminated by radiation from Fukushima it would show Cesium 137. See spectra below from contaminated area of Fukushima Prefecture.  The same instrument is identifying Cesium 137 rather than Radium and Thorium.

Sample of deck material from contaminated area of Fukushima Prefecture

Sample of deck material from contaminated area of Fukushima Prefecture

The picture below is a geiger counter measuring the activity in a sample bag of the sand. The radiation level is elevated, but roughly equivalent to some granite counter top material from Brazil.


This is a geiger counter with 2 inch pancake detector measuring the activity in the sand sample

Whether this material is naturally occurring at this beach or not remains a question. There are also reports that a pipeline was once at this location.  We hope the State will do further testing to determine the origin and full nature of the hot spots on the beach. But we are confident that it is not related to Fukushima, based on the spectral signature.  We expect more news later today.


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By Corbett| 2 Comments | News


  1. Finnaly someone is getting the truth out . I understand the fear mongering is good for you tube hits but I can’t stand people using fear to make a profit or gain popularity . Just as bad as corporations impacting public health for a dollar . The situation is far from over but stress will kill you just as fast as radiation.

  2. Darn…and I thought this place was the dumping ground for the world’s largest hoard of red Fiestaware. The government said it so therefore I thought it was true! (And yes…for the sarcasm impaired… I am kidding.)

    The Thorium makes me wonder if there might be some monzonite in the sand as it is a naturally occurring form of sand that is radioactive. It’s actually the first thing that came to mind when I heard this story since it is a fairly well known naturally occurring form of radiation. It’s probably only coming to light now since people are more aware now and more likely to check beaches with geiger counters that have never been tested before.

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