How about this theory ?? (Jay, I know you said in your 1st note that you had checked communication but...)Many mitigators would agree that it is more often than not a good idea to locate your main suction or vacuum point around the perimeter of the slab rather than the middle of the slab as common sense would dictate. One reason this is true is that most builders/contractors do a lousy job of compacting the earth or fill materials below the slab. Concrete appears brittle but is really amazingly flexible. If the fill or earth material below the slab settles say 1/4 inch over 20 or 30 years, the center of the slab will usually drop down with the fill below (often without cracking), however since the perimeter of the floorslab is often resting on a footing or masonry wall of some sort, the perimeter usually does not settle, and often there is a small gap between the bottom of the slab and the fill materials below which we can utilize for air movement or establishing a broader vacuum field.My theory, for what it is worth, is that the weight and mass of this huge pile of wood was depressing the floorslab and closing up any minute gaps between the slab and the fill below. When the weight was removed, the slab said "ahhhhh", relaxed, rose ever so slightly, allowing you to pull air below that section, or establish a broader or more complete vacuum field.........or maybe without this massive pile of wood down there, you just have better air movement or circulation in the basement area in general, allowing for better dilution of the radon gas.On Mon, May 16, 2011 at 2:09 PM, Bruce Thomas wrote: I find it fascinating as well. Bill Broad head did some work on radon in the tree tops. He may want to weigh in on this. If the guy has any wood left or an unfinished small project you could confine it and test it, just to see what happens. This is why I subscribe the this list. Bruce On 5/16/2011 2:00 PM, Jay Bauder wrote: My scientific background doesn’t go too far beyond the celery in food coloring experiment, but I do find the responses, both private and private to be absolutely fascinating! Thanks! -Jay ___________________________________From: International Web Resource for Radon Professionals [ mailto:RADONPROFESSIONALS@LIST.UIOWA.EDU] On Behalf Of Martin Edelson Sent: Monday, May 16, 2011 1:42 PM To: RADONPROFESSIONALS@LIST.UIOWA.EDUSubject: Re: [RNPROF] Radon in wood? There is a large literature demonstrating the ability of trees to incorporate minerals they are in contact with through the environment. With particular reference to uranium, I looked into the incorporation of uranium into trees located on the Iowa State University campus in Ames , IA. During WWII, Iowa State University (then Iowa State College) participated in the Manhattan Project by utilizing a novel method to purify uranium metal destined for the first reactors at the University of Chicago and Oak Ridge . Something on the order of a million pounds of uranium ore were secretly processed in Ames . The university, which tore down the uranium processing facility on campus after the war, left trees adjacent to the facility standing. We took core samples from these trees and utilized inductively coupled plasma-mass spectroscopy with laser ablation sampling to measure uranium captured in tree rings. We were able to show that trees in the vicinity of the facility had excess uranium in tree rings. We also found lead taken up by trees in an EPA listed site near Des Moines . This site had once been used for battery cracking operations and, as a result, suffered from lead soil contamination. Given that uranium and other metals can be taken up by trees, wood planks could act as a source term for radon. However I do not know whether they can make a meaningful contribution to the radon in a structure without doing some calculations. It is also true that the trees we sampled were in locations with potentially extensive soil contamination. It may not be reasonable to expect trees in more pristine locations to show such effects. The first time I heard about this property of trees was at a meeting where Oak Ridge scientists described using such measurements to monitor acid raid in the Smoky Mountains . They found that the acidic nature of rain mobilized certain metals in soil minerals and that they could monitor the severity of acid rain by measuring the uptake of these metals in trees. When acid raid occurred, the trees were able to incorporate a greater concentration of the mobile metals then they had in the past. On 5/16/2011 11:56 AM, Michael E. Kitto wrote: I agree with Bill, in that I see no way the wood could be a natural source for the radon unless the wood was contaminated with self-luminous paints, etc. or the soil had excessive amount of radium (or precursors). Uptake through the root system would be inefficient unless the tree(s) behave like Brazil nuts and adsorb Group 2 elements. My opinion - Mike Kitto Inactive hide details for "Field, R W" ---05/16/2011 12:22:13 PM---"Field, R W" "Field, R W" ---05/16/2011 12:22:13 PM---"Field, R W" "Field, R W" Sent by: International Web Resource for Radon Professionals 05/16/2011 12:22 PM Please respond to "Field, R W" To RADONPROFESSIONALS@LIST.UIOWA.EDUcc Subject Re: Radon in wood? In my view, the wood is likely not the source of radon unless the wood was contaminated with radium-226 in the past by some unusual scenario. Wood products contain low levels of various radionuclides especially in areas that have been contaminated by a nuclear accident, nuclear releases, etc. http://www-pub.iaea.org/MTCD/publications/PDF/te_1376_web.pdfIn …; most cases, radium-226 would not be a common radionuclide released by nuclear-related activities. Radium was previously used in self-luminous paints, as a component of lightning rods, to treat medical conditions (in the 1900s), etc. More information would be needed to assess any association between the wood and possible radium contamination. The radium-226 content of the wood, if it was still available, could be assessed. Perhaps others would have additional insights or opinions. From: Jay Bauder [ mailto:jbauder3@comcast.net] Sent: Monday, May 16, 2011 9:00 AM To: Field, R W; RADONPROFESSIONALS@LIST.UIOWA.EDUSubject: Radon in wood? I have an anecdotal story and a question for the scientist/researchers in the group. A while back, I had a rather unique home to mitigate. It had been built in the 1950’s with no stone under the slab. The garage slab had a dirt crawlspace under it, a condition that is very odd (at least in South Central Pennsylvania). It also had a sub-floor waterproofing system with a plastic waffle material at the floor wall joint that protruded about 6” up along the foundation along the back wall. The original radon readings were 18 pCi/l. The system design consisted of an external fan on the back corner of the home, a suction point directly inside, a suction point on the far side, away from the waterproofing system, and a suction point through the rubber roofing that we installed in the crawlspace. We sealed the top of the waterproofing system, made sure the top of the wall was sealed, sealed the sump lid and all the cracks that we could access. The post test came back at 6 pCi/l. We returned, checked the pressure field extension, and everything seemed to be fine. The vacuum reading was well within manufactures specifications. We added a fresh air supply to the oil furnace. The post test results again came back at 6 pCi/l. At this point, it was fair to say that I was frustrated. I told the homeowner that I wasn’t sure what to do next, but with all the wood that he had stored in the basement (close to 40% of the basement was stacked floor to ceiling with oak, cherry, walnut, and various other hardwoods) I couldn’t inspect the entire floor. I told him perhaps there was a drywell floor drain that was causing the problem. He agreed to sell the wood. He said that he had it for 20 or 30 years, and wouldn’t be able use it all anyway. Once the basement was cleared, we inspected the floor and checked pressure field extension in the areas that were covered. Everything seemed fine. We took grab sample readings and couldn’t detect any significant radon or radon source. We provided (2) more charcoal canisters. Both came back at less than 1 pCi/l. My question; Can trees absorb uranium decay products through their root systems and store them in the wood? I do realize that with homes that have slabs poured on dirt, the longer they systems operate, the more moisture is pulled from the soil and the greater the pressure field extension will become, but this just didn’t strike me as one of those occasions. I look forward to your responses, Jay Bauder Bauder Basement Systems, Inc ___________________________________No virus found in this message. Checked by AVG - www.avg.comVersion: 10.0.1375 / Virus Database: 1500/3636 - Release Date: 05/13/11 ********** RN PROF (Subscription changes - archives) - http://list.uiowa.edu/scripts/wa.exe?SUBED1=RADONPROFESSIONALS&A=1*********** ********** RN PROF (Subscription changes - archives) - http://list.uiowa.edu/scripts/wa.exe?SUBED1=RADONPROFESSIONALS&A=1*********** IMPORTANT NOTICE: This e-mail and any attachments may contain confidential or sensitive information which is, or may be, legally privileged or otherwise protected by law from further disclosure. It is intended only for the addressee. 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