Today s Overview. Lesson Objectives. Lesson 22: Radiation 15 November ENV H 311: Intro. to Environmental Health 1

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1 Introduction to Environmental Health Lesson 21. Radiation Protection 15 November 2013 Philip G. Campbell Dept. of Environmental Health & Safety University of Washington Today s Overview Radiation Uses & Exposure Health Effects Prevention & Control Lesson Objectives At the end of this lesson students should be able to: describe the different types of radiation and elucidate their health effects; identify different diseases associated with household and medical exposure to radiation; describe the difference between ionizing and non-ionizing radiation; and, apply the "engineering control strategies" to particular situations. ENV H 311: Intro. to Environmental Health 1

2 Additional credits or writing ( W ) credit available. Visit times are spread out through the week. All tutors must attend an orientation. Please visit expd.uw.edu/pipeline for schedule. Center for Experiential Learning & Diversity 171 Mary Gates Hall expd.uw.edu/pipeline pipeline@uw.edu IMPACT THE LIFE OF A K-12 STUDENT & TRANSFORM YOUR OWN. Volunteer Service The Pipeline Project recruits, trains, and places students as volunteer tutors in schools and community organizations. Inner Pipeline Seminars Register for an Inner Pipeline seminar. Students tutor in schools and attend a weekly seminar focusing on a wide range of current educational topics and receive academic credit. In the time schedule under the College of Education and EDUC 401. Alternative Spring Break Spend your spring break in a rural or tribal community of Washington working with local schools on a literacy/arts or environmental science project. Register for EDUC 260 through high school visit (EDUC 369) OR Sign up on our website as a volunteer: dreamproject.org/join Mary Gates Hall uwdreamproject@uw.edu Lesson 22: Radiation 15 November 2013 Announcements Announcements Join the Dream Project. DREAM PROJECT UW students involved in both Pipeline & Dream Projects come from all backgrounds and disciplines If interested, download a copy of this flyer from today s module. The Dream Project will teach you how to be a mentor for firstgeneration and low-income students in King County high schools as they navigate the complex college admissions process. 2 I&S credits (EDUC 260 & EDUC 369) Weekly high school visit at one of 17 schools Additional events throughout the quarter Keep in touch with your high-school mentee Write two 1-page reflection papers How to Join MyUW if you want the two credits. You must register for the weekly lecture and a Announcements DEOHS Seminar: Title: Moving from Knowing to Doing: Dissemination and Implementation Research in Clinical and Community Settings Panel Discussion: Jeffrey Harris, MD, MPH, Professor, Health Services (Moderator) Peggy Hannon, PhD, MPH, Associate Professor, Health Services Christian Helfrich, PhD, MPH, Research Assistant Professor, Health Services Date: Thursday, 21 November2013 Time: 12:30-1:20 p.m. Room: T-435, HSC ENV H 311: Intro. to Environmental Health 2

3 Radiation and Environmental Health Radiation from space Radiation from earth and building materials Radiation in food Radiation and Environmental Health Waste Disposal Nuclear Power Consumer Products Medical Uses If something goes wrong it may have a huge impact on public health! Topics What is radiation and where does it come from? What are the effects of radiation exposure? What can be done to minimize radiation exposure? What sources of radiation can be found in the workplace? Who regulates the use of radiation? ENV H 311: Intro. to Environmental Health 3

4 Radiation means matter or energy moving outward from a point of origin. Wilhelm C. Roentgen ( ) In 1895, while working with electricallyenergized, sealedglass Crookes tubes, he discovered that photographic plates kept near the tubes become darkened. X-Ray Photography Roentgen assumes previously unknown X-RAYS are escaping the tube. Roentgen makes photo images with x-rays and shows they easily penetrate soft tissue. ENV H 311: Intro. to Environmental Health 4

5 Henri Becquerel ( ) In 1896, discovered other invisible rays coming from natural Uranium would also darken photo plates. Roentgen and Becquerel had discovered IONIZING RADIATION Ionizing Radiations (causing alteration of photo media) are generated by high energy natural or manmade processes occurring within the atom. Ionizing Radiation Possess enough energy to remove electrons from atoms, creating ion pairs. These ion pairs then go on to create highly reactive chemicals that can damage DNA and other important cellular molecules. ENV H 311: Intro. to Environmental Health 5

6 The FIVE basic types From the nucleus From the electron shells Electromagnetic Radiation No Mass No Charge Very Penetrating Particulate Radiation Includes alpha, beta, and neutron Has mass and charge Not very penetrating ENV H 311: Intro. to Environmental Health 6

7 Where does it come from? Can be naturally occurring or man-made Produce radiation at all times, but decays away over time. Often unsealed and loose, and can be easily spread around (contamination). Where does it come from? Machine Produced X-ray Machines, cyclotrons, accelerators, etc. Most produce x-rays but particles also possible. Only produce radiation when energized. High energy machines can activate materials to create radioactive materials. Penetration ability of some radiations ENV H 311: Intro. to Environmental Health 7

8 Radioactive Decay After Time Pure Sample Full Activity Decayed Sample Lower Activity Activity Describes how much radioactive material is present at any given time. Units = Bequerel (Bq) or Curies (Ci) 1 Bq = 1 decay per second Usually expressed in Mega (10 6 ) or Giga (10 9 ) 1 Ci = 3.7 x decays per second Usually expressed as milli (10-3 ) or micro (10-6 ) Simple Half-Life Calculation x t A = A o e t 1/2 Activity decreases over time by a rate defined as the half-life. (i.e. the amount of time it takes the activity to decrease by one-half) ENV H 311: Intro. to Environmental Health 8

9 Radioactive Decay Radiation Dose Absorbed Dose amount of energy absorbed per unit mass Units = Gray (Gy) or rad 1 Gy = 100 rad Dose Equivalent Absorbed Dose adjusted for biological damaging ability. Units = Sievert (Sv) or Rem 1 Sv = 100 rem Often expressed as milli (10-3 ) or micro (10-6 ) Natural Background Radiation Average dose in the US 3.1 msv/yr (310 mrem/yr) ENV H 311: Intro. to Environmental Health 9

10 Cosmic Radiation Levels Terrestrial Radiation Levels ENV H 311: Intro. to Environmental Health 10

11 Radiation Health Effects High-level radiation effects are acute effects which are manifested shortly after (hours, days, weeks) a large exposure (1 Sv or 100 rem+). Low-level radiation effects are described as latent effects, appearing many years after a non-lethal acute dose, or chronic effects after many years of small doses (like radiation workers). High Level Radiation Effects Acute Radiation Syndrome Bone Marrow Injury (over 1 Sv or 100 rem) may cause death if injury is severe. GI Tract Injury (over 6 Sv or 600 rem) causes death in days or weeks. Central Nervous System Injury (over 50 Sv or 5000 rem) causes death in hours or days. Radiation Burns (over 2 Sv or 200 rem) local or whole body Cataracts (over 1.5 Sv or 150 rem) Low Level Radiation Health Effects Genetic mutations has not been observed in humans, but has been observed in animal populations Abnormalities induced in an exposed fetus depends on dose and period of pregnancy. The risk of abnormality is considered negligible at 5 rad or less when compared to the other risks of pregnancy. (NCRP Report 54) ENV H 311: Intro. to Environmental Health 11

12 Low Level Radiation Health Effects Cancer 0.1 Sv (10 rem) given to 100 people in U.S. population would be expected to cause about 1 extra cancer over a lifetime. About 42 of these people would be expected to get cancer from natural causes. BIER VII Report Fate of Early Radiologists Radiologist Fingers ENV H 311: Intro. to Environmental Health 12

13 Early Radiation Injury 1898 Photograph shows severe chest burn on a United States soldier in the Spanish-American War, caused by repeated exposure to X rays. Annual Radiation Dose Limits Occupational 0.05 Sv (5 rem or 5000 mrem) whole body individual organs, skin and extremities (50 rem) Exception: Lens of eye = 0.15 Sv (15 rem) Embryo/Fetus (of radiation worker) 5 msv (0.5 rem) General Public 1 msv (0.1 rem) Types of Radiation Exposure Usually much greater at entrance than exit. May come from inhalation, ingestion, injection, absorption, or injury Could be partial or whole body. External vs. Internal Often concentrates in particular organs. ENV H 311: Intro. to Environmental Health 13

14 3 Principal Means to Reduce External Exposure Time - reducing the amount of time around a radiation source directly reduces radiation exposure. Distance - exposure reduces exponentially with increased distance from the source. Shielding - stops alpha and beta particles and greatly reduces x-ray and gamma radiation. Increase Distance Follows 1/r 2 relationship For example; doubling your distance cuts exposure to 1/4, and tripling distance cuts exposure to 1/9. Methods to Reduce Internal Intake Containment and/or exhaust (e.g., fume hoods in labs). Contamination surveys. Good hygiene - washing hands, contaminated skin, and contaminated articles. Good personal habits no hand to face/mouth contact, no eating/ drinking, no application of cosmetics. Use of protective clothing and personal protective equipment. General Protective Measures: Knowledge of hazards. Area Control: signage, records, and security. Appropriate facilities and equipment for use and control of radioactive materials. ENV H 311: Intro. to Environmental Health 14

15 Radiation Use Availability and use of radioactive materials exploded after World War II. Radiation in the Workplace Research Medicine Radiation Therapy Laboratory Use Irradiations Nuclear Medicine Radiation in the Workplace Measurement and Quality Control Measure Thickness Static Control Industrial Radiography Measure Density ENV H 311: Intro. to Environmental Health 15

16 Radiation in the Workplace Baggage X-ray Radiation in the Environment Biomedical/Industrial wastes or byproducts Lost sources Radiation in the Environment Active Production or Processing Sites Closed/Abandoned Production or Processing Sites ENV H 311: Intro. to Environmental Health 16

17 Radiation in the Environment Nuclear Accidents Radiological Dispersal Devices October 2007 (Washington Post): A US government advisory panel warns that terrorists could use the cesium-137 in irradiation machines to make dirty bombs. Detecting Incoming Radioactive Materials Borders Seaports Airports ENV H 311: Intro. to Environmental Health 17

18 Protection & Regulation Radioactive Materials Nuclear Regulatory Commission (NRC) Agreement States Radiation Manufacture Machines Food & Drug Administration (FDA) Use States Environmental Protection Environmental Protection Agency (EPA) Nuclear Security Department of Homeland Security (DHS) Transport Department of Transportation (DOT) Contact Information Radiation Safety Office 201 Hall Health Box (206) Satellite Office Health Sciences Building Room T274 (206) Website Next Lesson Air Pollution & Health ENV H 311: Intro. to Environmental Health 18