PROBLEM. How does residential development of formerly mined lands influence the amount of ionizing radiation in the resulting residential community?

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2 PROBLEM How does residential development of formerly mined lands influence the amount of ionizing radiation in the resulting residential community?

3 HYPOTHESIS If ionizing radiation is measured in the soils of residential and undeveloped land previously mined for phosphate, then the residential soils will show significantly lower levels of radiation because of the effect of legal liability and soil stability on where the developer sites the residential community.

4 MATERIALS Materials Used in Soil Sampling: Radex RD Geiger Counter Post Hole Digger Tape Measure Safety Glasses Closed-Toe Shoes Plastic Freezer Bags Measuring Scoops Computer Triple Beam Balance Protective Gloves Materials Used in Lab Preparation and Analysis: High Purity Germanium Detector Apron Electric Can Sealer Electronic scale Face Shield Aluminum Cans (400g soil) Hammer Black Permanent Marker

5 PROCEDURES 1. Using historical images, locate at least three sampling sites on previously mined lands that currently contain both undeveloped land and land developed into residential property. 2. Research levels of cosmic radiation and general background radiation in Central Florida and radiation levels of previously mined land in Polk County (to compare to scientist s levels). 3. At each sampling site, begin measuring ionizing radiation with a hand-held Geiger counter at 1 meter above the surface until sampling at site is complete. Measure readings for five minutes in installments of one measure a minute. 4. Use the post-hole digger (operated by designated supervisor) to obtain a soil sample of at least 400 grams at a depth of half a meter below the surface and place sample in plastic freezer bag that is marked for location. 5. Record radiation readings from Geiger counter and coded location of site sample. 6. Take samples to lab at Bureau of Radiation Control in Orlando. 7. Prepare samples for testing by homogenizing soil by grinding and mixing, and measure out 400 grams using an electronic scale. 8. Label soil bags and aluminum cans and seal cans using an electric can sealer. Let samples rest for a minimum of 14 days to allow stabilization of elements in can. 9. Place soil samples in high purity germanium detector and test for the amount of radioactive activity in the sample, esp. Radium 226, Lead 214, Bismuth 214 (lab personnel). 10. Dispose of tested soil samples in designated receptacle. 11. Record results from both lab and in-field testing. Analyze results.

6 PHOTOS Soil Sampling Photos taken by James Lovely

7 PHOTOS Lab Preparation & Analysis Photos taken by James Lovely

8 SITE MEASUREMENTS The data supports my hypothesis as average gamma readings from formerly mined lands that have been developed (in shaded columns) are lower than those of formerly mined lands that remain undeveloped. Charts by Elizabeth & James Lovely

9 EPA REDBOOK DATA Data presented from 672 outdoor gamma exposure measurements taken by the EPA on reclaimed mining land in Polk County. The average gamma measurement for the 672 sites was 0.11 µs / hour. The average gamma measurement for the 3 residential sites in this experiment was µs / hour, near the EPA average for reclaimed mining land. The average gamma measurement for the 3 undeveloped sites in this experiment was µs / hour, or within the top 10% of EPA readings for reclaimed mining land. Source: Indoor Radiation Exposure Due to Radium in Florida Phosphate Lands, U.S. Environmental Protection Agency, Office of Radiation Programs, EPA 520/ , Feb. 1979, Table 4, Page 27 (units in original table converted from µr / hour to µs / hour ). Charts by Elizabeth & James Lovely

10 RADIOACTIVITY In order to confirm that the gamma radiation measurements taken at the six (6) formerly mined sites were related to the actual presence of radioactivity in the soil at those sites, I took soil samples at a depth of ½ meter at each site. Ionizing Radiation & Radioactivity μsv/h Bq/g Ra 226 S1R S1U S2R S2U S3R S3U Working with the State of Florida s Bureau of Radiation Control, I was able to prepare those soil samples for testing in a high purity germanium detector. The tests revealed a very high (~ 93%) correlation between the average gamma radiation reading obtained at each sample site and the amount of radioactivity from the related soil sample attributable to Radium 226, Lead 214 and Bismuth 214, which are isotopes in the decay chain for Radium 226. Note: Special thanks to the State of Florida s Bureau of Radiation Control Orlando Office.

11 RADIOACTIVITY Ionizing Radiation & Radioactivity μsv/h Bq/g Pb 214 S1R S1U S2R S2U S3R S3U Ionizing Radiation & Radioactivity μsv/h Bq/g Bi 214 S1R S1U S2R S2U S3R S3U Charts by Elizabeth & James Lovely

12 CONCLUSION Ionizing radiation was measured in the soils of residential and undeveloped land previously mined for phosphate, and the residential soils showed significantly lower levels of radiation. The average levels of ionizing radiation at the residential sites were as follows: 0.124; 0.112; and micro-sieverts/hr. The undeveloped sites had average radiation levels of: 0.164; 0.188; and micro-sieverts/hr. The still undeveloped areas had radiation levels that were from 132% to 195% higher than those of current residential areas. Through analysis of radioactivity in the soil, it was determined that there was a 93% correlation between the radioactivity of each soil sample and the radiation reading taken at the related sample site. The average levels of radioactivity at the residential sites were as follows: (Bi 214); (Pb 214); and (Ra 226) Becquerels/gram. The average levels of radioactivity at the undeveloped sites were as follows: (Bi 214); (Pb 214); and (Ra 226) Becquerels/gram. These results prove the scientist s hypothesis that residential soils on formerly mined lands have significantly lower levels of both ionizing radiation and radioactivity than undeveloped soils. Experimentation based on these findings could include further testing of radiation and radioactivity 1) in different types of soils (e.g., sands or clays) in previously mined areas, 2) in a larger number of samples, 3) focusing on the historical use of the sample site within the mining process. This experiment was especially strong in testing across multiple mine sites, taking samples from a considerable depth, testing for ionizing radiation at the location, and evaluating radioactivity at a regulated research institution with very sensitive gamma radiation detectors. The results and findings of this experiment could be used by real estate developers looking to build on formerly mined land and citizens when evaluating the history and safety of the communities in which they live. The results and findings of this experiment will also help to encourage government bodies that authorize development of formerly mined land to fulfill their ongoing responsibility to ensure that such land is reclaimed properly.