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Radon School Survey in North Dakota 1989-1992 INTRODUCTION Background During the period 1989 to 1992, the North Dakota State Department of Health and Consolidated Laboratories (NDSDHCL) offered to test for radon in 383 school districts. Three hundred eighty-three represents all public and private nonprofit schools, grades K through 12 in North Dakota. Of the 383 districts, 217 districts chose to participate. Sampling The Department followed EPA guidance for sampling protocol. Ten percent of school rooms were provided duplicate samples and every twentieth room received a control sample. School districts submitted plans and sketches of their facilities to the Department. Department personnel approved the selections of sampling sites. Classrooms that were utilized the most were given the highest priority. The database contained 9,748 samples from 217 school districts. The number of school districts not represented in this survey was 166. Many samples were lost, not analyzed, or were refused. The following types and numbers of samples were deleted from the original database: Controls 412
Duplicate 906
TOTAL 1,318
The final database contained 879 official duplicate samples and
7,551 regular samples for a total of 8,430 samples.
217
% school district recovery = --- x 100 = 56.4%
383
101,664
% school population recovery = ------- x 100 = 86.4%
117,719
Discussion This survey was voluntary and, in certain counties, none of the school districts submitted any samples. These counties were: Foster, Griggs, Sheridan, and Slope. Some of the school districts in these counties began testing, using commercial vendors, before the Department began its survey. They were offered free testing by the Department but chose not to participate. The county percentage of samples whose concentration is greater than 4 picocuries per liter is shown in Table 11, whereas the city/county statistical summary is presented in Table 12. TABLE 10 SCHOOL SURVEY STATISTICS BY PARAMETER
NUMBER PERCENT ARITHMETIC PERCENT OF SAMPLES
OF OF ARITHMETIC STANDARD GREATER THAN:
FLOOR SAMPLES SAMPLES MEAN DEVIATION 4 pCi/l 20 pCi/l
B 260 3.1 2.8 4.1 16.2 1.5
1 8,165 96.9 1.8 2.4 7.4 0.3
2 5 0.1 2.7 1.9 20.0 0.0
All 8,430 100.0 1.8 2.5 7.7 0.3
Two different companies were employed by the NDSDHCL to test radon in North Dakota schools. Home Radon Detection, Inc. (HRDI) of Grayslake, Illinois tested 7,543 samples. HRDI utilized a charcoal canister for a 48hour test period. Radon Testing Corporation of America (RTCA) of Irvington, New York tested 2,121 samples using a charcoal canister with a diffusion barrier for 7 days. Quality Assurance The average radon concentration for the 412 controls was 0.2 pCi/l with a standard deviation of 0.4. The precision was determined by utilizing a coefficient of variation computer program. Some variations were quite large and may indicate an error in labeling, etc. The average coefficient of variation was 17.86% which indicates the data may have had poor precision. No accuracy samples were taken during this survey. Figure 3 indicates the data is lognormal at higher concentrations. The comparison of schools to the other surveys may be found in Figure 8. FIGURE 4 - SCHOOL ROOM RADON STUDY 1989-1992
Number of samples: 8430 Summary and Conclusions This survey has shown that of the school rooms tested, the maximum concentration was 66.2 pCi/l. The percentage of rooms with concentrations greater than 4 pCi/l or 20 pCi/l are 7.7% and 0.3%, respectively. The mean radon concentration for 8,430 samples was 1.8 pCi/l with a standard deviation of 2.5. TABLE 11 SCHOOL SURVEY STATISTICS BY COUNTY PERCENTAGE PERCENTAGE
NUMBER ARITHMETIC OF SAMPLES OF SAMPLES
OF ARITHMETIC STANDARD GREATER THAN GREATER THAN
COUNTY SAMPLES MEAN DEVIATION 4 pCi/l 20 pCi/l
Adams 52 2.2 1.9 5.8 0.0
Barnes 135 2.2 1.6 9.6 0.0
Benson 83 1.9 1.4 4.8 0.0
Billings 37 2.7 2.1 18.9 0.0
Bottineau 72 0.7 0.5 0.0 0.0
Bowman 101 2.5 2.9 21.8 0.0
Burke 18 1.2 0.7 0.0 0.0
Burleigh 615 1.0 0.9 1.5 0.0
Cass 1102 1.6 2.0 6.2 0.2
Cavalier 102 1.2 0.8 0.0 0.0
Dickey 59 1.7 3.0 10.2 1.7
Divide 50 0.5 0.4 0.0 0.0
Dunn 45 1.1 0.9 2.2 0.0
Eddy 37 1.6 1.5 5.4 0.0
Emmons 116 2.3 1.8 14.7 0.0
Golden 75 1.0 0.6 0.0 0.0
Valley
Grand 706 1.3 1.4 5.0 0.0
Forks
Grant 42 3.3 3.4 42.9 0.0
Hettinger 43 4.4 3.3 34.9 0.0
Kidder 48 2.4 1.7 14.6 0.0
Lamoure 43 2.3 3.0 7.0 2.3
Logan 75 1.2 0.8 1.3 0.0
McHenry 166 1.3 1.7 7.2 0.0
McIntosh 116 2.5 1.4 13.8 0.0
McKenzie 113 2.0 1.1 2.7 0.0
McLean 193 1.8 1.6 8.3 0.0
Mercer 279 1.7 1.1 3.9 0.0
Morton 320 1.6 1.6 5.0 0.0
Mountrail 172 1.2 1.1 2.3 0.0
Nelson 67 1.8 1.5 6.0 0.0
Oliver 43 1.7 1.2 4.7 0.0
Pembina 128 2.2 2.8 17.2 0.0
Pierce 63 1.5 0.9 0.0 0.0
Ramsey 169 1.8 1.5 11.8 0.0
Ransom 103 5.0 4.2 49.5 1.0
Renville 99 1.1 0.8 0.0 0.0
Richland 160 1.4 2.0 6.9 0.0
Rolette 136 1.1 1.1 3.7 0.0
Sargent 98 2.9 3.2 27.6 0.0
Sioux 50 1.8 0.9 2.0 0.0
Stark 389 4.5 6.2 21.6 4.6
Steele 28 0.9 0.8 0.0 0.0
Stutsman 283 2.0 2.0 10.6 0.0
Towner 97 1.0 0.7 0.0 0.0
Traill 162 2.1 3.5 6.8 1.2
Walsh 205 3.0 5.8 19.0 2.0
Ward 845 1.3 1.2 2.8 0.0
Wells 55 1.1 1.0 0.0 0.0
Williams 235 1.8 1.7 4.3 0.0
TABLE 12 SCHOOL SURVEY STATISTICS BY CITY/COUNTY PERCENT PERCENT
SAMPLES SAMPLES
NUMBER ARITHMETIC GREATER GREATER
OF ARITHMETIC STANDARD THAN THAN
COUNTY CITY SAMPLES MEAN DEVIATION 4 pCi/l 20 pCi/l
Adams 52 2.15 1.86 5.8 0.0
Hettinger 38 1.46 0.76 0.0 0.0
Reeder 14 4.04 2.53 21.4 0.0
Barnes 135 2.17 1.65 9.6 0.0
Valley City 111 1.89 1.62 5.4 0.0
Wimbledon 24 3.51 0.97 29.2 0.0
Benson 83 1.86 1.40 4.8 0.0
Esmond 20 1.57 0.88 5.0 0.0
Fort Totten 31 1.22 1.33 6.4 0.0
Leeds 32 2.66 1.34 3.1 0.0
Billings 37 2.72 2.09 18.9 0.0
Fryburg 11 1.92 0.55 0.0 0.0
Medora 26 3.06 2.39 26.9 0.0
Bottineau 72 0.73 0.49 0.0 0.0
Bottineau 72 0.73 0.49 0.0 0.0
Bowman 101 2.49 2.87 21.8 0.0
Bowman 70 2.12 2.19 18.6 0.0
Rhame 8 9.54 1.95 100.0 0.0
Scranton 23 1.17 0.94 4.3 0.0
Burke 18 1.19 0.66 0.0 0.0
Bowbells 18 1.19 0.66 0.0 0.0
Burleigh 615 1.05 0.93 1.5 0.0
Bismarck 609 1.01 0.84 1.0 0.0
McKenzie 3 2.77 0.17 0.0 0.0
Menoken 3 6.50 0.86 100.0 0.0
Cass 1102 1.63 1.96 6.2 0.2
Amenia 3 1.63 0.05 0.0 0.0
Argusville 25 0.72 0.52 0.0 0.0
Casselton 52 3.67 2.73 40.4 0.0
Davenport 26 3.09 1.09 19.2 0.0
Fargo 653 1.84 2.16 5.8 0.3
Hunter 24 1.48 1.19 8.3 0.0
Kindred 84 0.80 0.76 1.2 0.0
Mapleton 10 1.64 0.28 0.0 0.0
West Fargo 225 0.83 0.78 0.4 0.0
Cavalier 102 1.21 0.77 0.0 0.0
Langdon 76 0.82 0.39 0.0 0.0
Munich 26 2.33 0.43 0.0 0.0
Dickey 59 1.70 2.97 10.2 1.7
Ellendale 22 1.92 1.46 9.1 0.0
Oakes 37 1.57 3.58 10.8 2.7
Divide 50 0.51 0.37 0.0 0.0
Crosby 50 0.51 0.37 0.0 0.0
Dunn 45 1.14 0.88 2.2 0.0
Dodge 5 2.22 0.28 0.0 0.0
Killdeer 40 1.01 0.83 2.5 0.0
Eddy 37 1.59 1.47 5.4 0.0
New Rockford 37 1.59 1.47 5.4 0.0
Emmons 116 2.27 1.79 14.7 0.0
Braddock 8 1.19 0.41 0.0 0.0
Hague 7 5.77 0.61 100.0 0.0
Hazelton 24 1.85 0.83 0.0 0.0
Linton 48 1.40 1.28 6.3 0.0
Strasburg 29 3.49 1.82 24.1 0.0
Golden 75 1.04 0.64 0.0 0.0
Valley
Beach 61 1.16 0.64 0.0 0.0
Golva 14 0.51 0.28 0.0 0.0
Grand 706 1.31 1.45 5.0 0.0
Forks
Grand Forks 574 1.07 1.26 2.3 0.0
Larimore 50 1.60 1.13 8.0 0.0
Manvel 19 1.74 0.58 0.0 0.0
Northwood 28 3.24 1.67 39.3 0.0
Thompson 35 2.96 2.28 20.0 0.0
Grant 42 3.27 3.36 42.9 0.0
Carson 15 0.64 0.28 0.0 0.0
New Leipzig 17 4.68 4.28 47.1 0.0
Raleigh 10 4.81 0.12 100.0 0.0
Hettinger 43 4.38 3.28 34.9 0.0
Mott 22 3.73 3.71 27.3 0.0
Regent 21 5.07 2.59 42.9 0.0
Kidder 48 2.38 1.67 14.6 0.0
Pettibone 15 2.83 1.23 20.0 0.0
Tappen 17 1.00 0.48 0.0 0.0
Tuttle 16 3.44 1.85 25.0 0.0
Lamoure 43 2.28 3.02 7.0 2.3
Kulm 25 2.56 3.90 12.0 4.0
Verona 18 1.90 0.65 0.0 0.0
Logan 75 1.20 0.83 1.3 0.0
Gackle 30 0.55 0.33 0.0 0.0
Lehr 4 1.13 0.16 0.0 0.0
Napoleon 41 1.69 0.80 2.4 0.0
McHenry 166 1.13 1.67 7.2 0.0
Deering 7 1.31 0.24 0.0 0.0
Drake 14 1.07 0.43 0.0 0.0
Granville 36 0.85 0.46 0.0 0.0
Towner 43 0.55 0.32 0.0 0.0
Upham 14 0.89 0.57 0.0 0.0
Velva 52 2.51 2.53 23.1 0.0
McIntosh 116 2.49 1.39 13.8 0.0
Ashley 44 3.10 0.86 18.2 0.0
Wishek 49 1.66 1.58 10.2 0.0
Zeeland 23 3.10 0.65 13.0 0.0
McKenzie 113 2.02 1.14 2.7 0.0
Alexander 31 2.15 1.77 9.7 0.0
Cartwright 3 1.53 0.09 0.0 0.0
Sidney 2 3.80 0.00 0.0 0.0
Watford City 77 1.95 0.74 0.0 0.0
McLean 193 1.75 1.57 8.3 0.0
Butte 21 1.18 0.90 0.0 0.0
Garrison 37 1.89 2.23 16.2 0.0
Max 33 1.24 0.49 0.0 0.0
Turtle Lake 37 1.43 0.65 0.0 0.0
Underwood 31 3.00 2.36 32.3 0.0
Wilton 34 1.68 0.60 0.0 0.0
Mercer 279 1.68 1.07 3.9 0.0
Beulah 56 1.69 0.81 0.0 0.0
Golden Valley 18 4.29 0.85 55.6 0.0
Hazen 153 1.20 0.65 0.0 0.0
Stanton 28 2.40 0.91 3.6 0.0
Zap 24 1.89 0.59 0.0 0.0
Morton 320 1.57 1.60 5.0 0.0
Almont 11 2.34 1.14 18.2 0.0
Flasher 25 0.45 0.26 0.0 0.0
Glen Ullin 41 0.97 0.48 0.0 0.0
Hebron 25 3.53 3.68 24.0 0.0
Mandan 180 1.53 1.20 3.9 0.0
New Salem 38 1.62 1.17 2.6 0.0
Mountrail 172 1.19 1.06 2.3 0.0
New Town 62 0.58 0.53 0.0 0.0
Parshall 39 1.76 0.76 2.6 0.0
Plaza 22 1.70 1.71 13.6 0.0
Stanley 49 1.27 1.00 0.0 0.0
Nelson 67 1.84 1.50 6.0 0.0
Aneta 19 3.65 1.48 21.1 0.0
Petersburg 19 0.56 0.56 0.0 0.0
Tolna 29 1.49 0.47 0.0 0.0
Oliver 43 1.66 1.15 4.7 0.0
Center 43 1.66 1.15 4.7 0.0
Pembina 128 2.19 2.81 17.2 0.0
Cavalier 51 1.90 2.54 5.9 0.0
Drayton 56 0.84 0.45 0.0 0.0
St. Thomas 21 6.47 2.92 90.5 0.0
Pierce 63 1.46 0.94 0.0 0.0
Rugby 63 1.46 0.94 0.0 0.0
Ramsey 169 1.85 1.54 11.8 0.0
Crary 9 2.73 1.08 22.2 0.0
Devils Lake 117 1.11 0.68 0.0 0.0
Edmore 21 3.13 1.73 28.6 0.0
Starkweather 22 4.17 1.52 54.5 0.0
Ransom 103 5.05 4.21 49.5 1.0
Enderlin 17 1.99 2.40 11.8 0.0
Lisbon 78 6.18 4.09 62.8 1.3
Sheldon 8 0.49 0.35 0.0 0.0
Renville 99 1.13 0.81 0.0 0.0
Glenburn 40 1.18 0.55 0.0 0.0
Mohall 44 0.59 0.37 0.0 0.0
Sherwood 24 2.06 0.82 0.0 0.0
Richland 160 1.35 1.97 6.9 0.0
Lidgerwood 6 2.70 0.94 16.7 0.0
Wahpeton 115 1.65 2.18 8.7 0.0
Wyndmere 39 0.25 0.12 0.0 0.0
Rolette 136 1.10 1.10 3.7 0.0
Belcourt 103 0.87 0.77 1.0 0.0
Mylo 3 3.70 0.78 66.7 0.0
Rolette 30 1.63 1.49 6.7 0.0
Sargent 98 2.87 3.16 27.6 0.0
Forman 42 1.52 0.92 2.4 0.0
Gwinner 29 7.04 2.68 89.7 0.0
Milnor 27 0.50 0.22 0.0 0.0
Sioux 50 1.80 0.94 2.0 0.0
Fort Yates 33 1.54 0.86 0.0 0.0
Solen 17 2.31 0.87 5.9 0.0
Stark 389 4.50 6.19 21.6 4.6
Belfield 33 14.49 13.02 60.6 45.5
Dickinson 310 3.11 3.69 11.9 1.0
Richardton 27 9.23 4.32 85.2 0.0
Taylor 19 3.07 0.90 21.1 0.0
Steele 28 0.91 0.79 0.0 0.0
Finley 28 0.91 0.79 0.0 0.0
Stutsman 283 1.96 1.98 10.6 0.0
Jamestown 188 1.93 2.31 14.4 0.0
Kensal 20 2.81 1.35 10.0 0.0
Medina 27 1.61 0.37 0.0 0.0
Pingree 28 2.28 0.87 0.0 0.0
Spiritwood 5 0.70 0.61 0.0 0.0
Streeter 15 1.58 0.88 6.7 0.0
Towner 97 1.00 0.72 0.0 0.0
Bisbee 21 0.94 0.50 0.0 0.0
Cando 47 0.86 0.68 0.0 0.0
Rock Lake 29 1.29 0.84 0.0 0.0
Traill 162 2.06 3.50 6.8 1.2
Buxton 28 1.40 0.63 0.0 0.0
Hatton 20 2.90 1.63 25.0 0.0
Hillsboro 48 2.67 5.97 6.3 4.2
Mayville 66 1.64 1.53 4.5 0.0
Walsh 205 2.99 5.81 19.0 2.0
Adams 23 1.74 0.84 4.3 0.0
Edinburg 22 1.39 1.11 9.1 0.0
Fordville 13 16.35 16.84 84.6 30.8
Grafton 105 2.02 2.31 17.1 0.0
Lankin 5 1.64 0.42 0.0 0.0
Minto 28 3.14 1.86 25.0 0.0
Nash 2 3.15 0.05 0.0 0.0
Park River 7 2.21 0.75 0.0 0.0
Ward 845 1.27 1.17 2.8 0.0
Berthold 24 0.26 0.09 0.0 0.0
Des Lacs 59 1.73 1.13 1.7 0.0
Kenmare 47 1.08 0.92 2.1 0.0
Makoti 13 2.85 0.79 15.4 0.0
Minot 611 1.22 1.16 3.1 0.0
Sawyer 25 1.80 1.98 4.0 0.0
Surrey 57 1.24 0.60 0.0 0.0
Wells 55 1.05 1.02 0.0 0.0
Bowdon 13 0.89 0.73 0.0 0.0
Fessenden 25 0.36 0.21 0.0 0.0
Hurdsfield 7 2.63 0.83 0.0 0.0
Sykeston 10 1.89 0.84 0.0 0.0
Williams 235 1.76 1.68 4.3 0.0
Tioga 60 1.52 0.81 0.0 0.0
Williston 175 1.84 1.89 5.7 0.0
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Copyright © 2012 North Dakota Department of Health |
