[ RadSafe ] Looking for guidance on when to post a "Soil Contamination Area"

[cobdw at tds.net]

Mr. Evers,
I have worked this situation both ways. First, you must look at the historical data if available and determine if there is high probability of exceeding the limits.  The samples are not the concern, it is the tools used to obtain the sample and the personnel collecting the samples.  If the tools are surveyed post sample collection and found to exceed the limits at your site you will have a work stoppage.  Depending on the area to be sampled and the depth that you must obtain and the method to collect the sample will determine if the prudent thing to do is to issue an RWP for contamination control.  Geoprobe sampling methods may not exceed the limits until you hit bedrock and that depends on the flow of subsurface water that can carry contaminants some considerable distance from the source.  I covered a similar activity as a RCT a couple of years ago.  We basically had to do a pre-job survey of the area, uppost to a CA, pull the samples, decon the the tools, perform a post jo!
 b survey and then down post the area.  Tyvek was required for all personnel handling the sampling tools and samples.  Some areas we fond nothing in the sample and then some samples were in the range of 60 mR/hr beta and gamma.  So, the prudent thing would be to issue an RWP, control the area and perform a post sample survey of the tools and equipment at each location.  I used an excel spread sheet to document the survey and found it to be very helpful in saving time.  If the samples are surface samples eg(within the first 15 cm of the surface) then I would recommend minimal PPE eg(gloves shoe covers maybe) perform a direct scan of the sample area and if the gross cpm of the sample area is above the BKG then consider the RWP Route and have a tech to control the area either by upposting or through continuous coverage.  I personally perfer to use a little common sense but the problem is the post decon of the tools and what is the suspect nuclide of concern.  Some nuclides will!
  be entrained in the soil and are hard to detect with a smear.  Others
 will seperate easily.  Another concern are environmental conditions eg (dry and loose or wet, muddy, and sticky) what is not transferable on a dry day will easily adhere to your clothes and shoes when wet.  Additionally, the skill of the samplers is an issue.  I have worked with some who were very neat and conciencous about getting the sample and not cross contaminating it. These types of guys could pull a sample in a tuxedo and not get a speck of dirt on them while others really get into their job and look like the dusty cloudy guy on the "Peanuts Gang" at the end of the day.
With all that said, I recommend coveralls as part of the PPE at a minimum for the samplers and due to the low administrative limits that are imposed on your site I highly recommend an RWP for contamination control with stop work statements when RA limits are reached or exceeded.
Good Luck,
Douglas W. Coble
Project Manager
Chase Environmental Group
 
> 
> From: "Evers, William C." <WILLIAM.C.EVERS at saic.com>
> Date: 2006/04/03 Mon PM 04:17:44 EDT
> To: " (radsafe at radlab.nl)" <radsafe at radlab.nl>
> Subject: [ RadSafe ] Looking for guidance on when to post a "Soil
> 	Contamination Area"
> 
> I work for a company that routinely does work sampling in soil excavations.
> I am working on a RWP for soil sampling in potentially contaminated areas.
> I have some historical data showing elevated soil concentrations in certain
> areas (Ra-226, Th-230, and U-238).  Our site limits on surface contamination
> are 20 dpm alpha, and 100 dpm beta.  My concern is that while sampling we
> may encounter areas where the elevated soil concentrations may lead to
> surface contamination in excess of our site limits.  I would like to know if
> this could happen prior to sampling so I could have the area posted as a
> "Contamination Area".
> 
> So my question is this: Is there an industry standard action level for soil
> contamination that can/will lead to surface contamination?  Is there an
> industry standard level where posting a "Contamination Area" becomes
> necessary?
> 
> Has anyone with a similar program ever encountered a situation like this
> before?  If so, any feedback would be greatly appreciated.  I would like to
> compare our procedures to other programs.  Thank you.
> 
>  
> 
> W. Clark Evers-
> 
>  
> 
>  
> 
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