Radiation and Magnuson Park Al Conklin Senior Health

Radiation and Magnuson Park Al Conklin Senior Health Physicist Office of Radiation Protection

Department of Health �By statute (RCW 70. 98) Department of Health is the Radiation Control Agency. �Mission: to protect and improve the health of people in Washington State.

Me �In radiation safety for 38 years (28 as a health physicist) � Studied health effects of plutonium � Regulated nuclear waste management and nuclear facilities � Performed Dose reconstruction for Hanford downwinders � Handled public health inquiries about Chernobyl, Fukushima and Hanford. � Currently a radiation instructor first responders and health care providers.

History of Radium �A natural isotope existing in nature; decaying from uranium. �When isolated, it glows in the dark. �In 1915, a radium paint was invented and used on WW 1 aircraft gauges so pilots could fly at night. �Became a standard for decades for clock faces, dials and gauges. �Its danger was discovered in the 1920 s when radium dial painters died from ingesting radium on their brushes.

Exposure Pathways for Radium �Swallowing substances contaminated by radium. �Radon gas given off by Radium– the most significant pathway � Measured as picocuries – or p. Ci – per liter of sampled air. ( 1 p. Ci = 1/ 1 trillionth of a curie) �External gamma exposure measured in units of rem or micro. R/ hour which equals 1/1 millionth of a rem

Radon Measurements in Buildings EPA Standard = 4. 0 p. Ci/L 11 locations tested All tests – less than 0. 3 p. Ci/L 4 locations tested All tests – less than 0. 3 p. Ci/L All tests were less than detectable - 0. 3 p. Ci/liter 30 2 Controls 3 locations tested All 3 tests less than 0. 3 p. Ci/L N 5 27 Mountaineers Bldg Sand Point Way Not enough radium in these buildings to cause any measurable radon concentrations.

Gamma Radiation – Outside Bldg 27 Radiation Surveys of Perimeter Fence micro. R/hour Grumbles 1 2 3 4 5 6 7 8 9 10 11 12 4 -6 7 -9 7 -9 7 -9 8 -10 7 -9 4 -6 Building 27 1 Conklin 2 4 -6 3 N 4 5 Shed 6 7 8 9 11 10 Fence 6 -8 8 -10 4 -6 Prior to Clean-up 12 Building 2

Gamma Radiation- Neighborhood Local Radiation Surveys for comparison 8 micro. R/hour Location 1 2 3 4 5 6 7 8 9 10 11 12 Bldg. 27 (Arena Sports) Results 8 to 10 7 to 8 5 to 7 5 to 10 7 to 9 4 to 6 4 to 5 5 to 8 12 10 7 11 2 6 9 5 4 3 1

Background Radiation Surveys in Seattle micro. R/hour Magnuson Park Lake City Way 4 to 6 Woodland Park 6 to 8 Queen Anne Hill 8 to 10 Pike Street Market Park 4 to 7 Safeco Field 7 to 9

External radiation exposure �Even before clean-up, exposure to radiation in the clean-up are was equivalent to area background levels. �THEN WHY CLEAN IT UP? � Some spots were significantly above backround � Clean-up requirements are very strict and conservative requiring clean-up to levels too low to accurately measure with instrumentation � The standard is based on a calculated level; it’s too low to be measured.

What does long term risk mean? �We know there is risk from higher exposures. �We can’t see it at extremely low exposures like the levels seen here. There is no reliable data. �However, there also no reliable data that proves the opposite. �Neither can be proven --- so, we based dose limits and clean-up standards assuming the risk is real, though we can, theoretically, calculate a risk all the way to a single atom.

Risk, continued �There has to be a clear pathway for exposure. �It must be conservative, but also must be realistic. �You have to account for: � different kinds of radiation (alpha, beta and gamma) � A reasonable maximum time of exposure (no one will sit on a spot in the elements for an entire year) � A clear defined pathway (ingestion, inhalation, external exposure) � There is no dose if a person is not exposed to a radiation source.

We can compare risks �Radiation scientists strongly caution against trying to calculate actual risks from such low standards. �However, since the Navy scenarios are based on theory of effects at low doses, we’ll go with that. �But, it’s important to put that calculated risk in perspective with other similar radiation exposures. �This means that if the risk from one radiation source is true, it has to be for the others. �The body cannot tell the difference between nature caused and man caused radiation.

Putting Numbers in Perspective Recreation in the Clean-up area* (from residual radium) mrem/hr 0. 02 Living in a brick building 0. 01 mrem/ hr One cross country flight 4. 0 mrem/trip One chest X-Ray 10. 0 mrem/X-Ray Dose from Radon – Seattle mrem/day Dose from Radon – Spokane mrem/day 0. 22 4. 3 Natural gamma background-Sandpoint neighborhood 0. 01 mrem/hr *Based. Eating on the EPA clean-up value of 15 millirem per year for any residual radium. one banana mrem/banana 0. 01

Translation – based on life styles, individuals’ doses can vary significantly � If you spend 200 hours at the clean-up site, you would receive 1/200 th of the radiation dose as you would get from 1 hour of flying in an airliner. (cosmic radiation) � For each hour you spend there, the radiation dose is the same as eating 2 bananas, (natural potassium is slightly radioactive). � The average annual dose from radon in: � Seattle is 80 millirem (doses vary) � Spokane is 1600 millirem (doses vary) � The 15 millirem standard is only theoretical but is lost in background doses from just living on the earth � We are talking about very low exposures here.

Clean-up work involving DOH �Building 27 � Contractor cleaned and reported surveys showing no residual contamination. � DOH would normally verify surveying 10% of the locations done by the contractor. � However, our inspectors chose to go beyond those survey points. Their findings: § Building was not clean. They found additional hot spots in corners, cracks, cubby holes, staircases, etc. � Contractor removed more material, requiring a new verification survey. Funding has been identified to conduct verification surveys. �Building 2 is releasable.

Conclusion This park will be a safe place to play, work or attend school Questions may be directed to: Al Conklin (360) 236 -3261 Al. conklin@doh. wa. gov