Office of Radiation and Indoor Air 

National Air and Radiation

Environmental Laboratory

EPA 402-R-09-007

June 2009

www.epa.gov/narel

Radiological Laboratory Sample 

Analysis Guide for Incidents 

of National Significance –

Radionuclides in Air

United States

Environmental Protection

Agency
EPA 402- R-09-007

www.epa.gov

June 2009

Revision 0

Radiological Laboratory 

Sample Analysis Guide for

Incidents of National Significance –

Radionuclides in Air

U.S. Environmental Protection Agency

Office of Air and Radiation

Office of Radiation and Indoor Air

National Air and Radiation Environmental Laboratory

Montgomery, AL 36115
This report was prepared for the National Air and Radiation Environmental Laboratory of the Office of Radiation

and Indoor Air, United States Environmental Protection Agency. It was prepared by Environmental Management

Support, Inc., of Silver Spring, Maryland, under contracts 68-W-03-038, work assignment 35, and EP-W-07-037,

work assignments B-33 and I-33, all managed by David Garman. Mention of trade names or specific applications

does not imply endorsement or acceptance by EPA.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

1 Departments of Agriculture, Commerce, Defense, Energy, Health and Human Services, Homeland Security, Interior,

Justice, and State, and the U.S. Environmental Protection Agency.

i

Preface

The document describes the likely analytical decision paths that would be made by personnel at a

radioanalytical laboratory following a radiological or nuclear incident, such as that caused by a

terrorist attack. EPA’s responsibilities, as outlined in the National Response Framework, include

response and recovery actions to detect and identify radioactive substances and to coordinate federal

radiological monitoring and assessment activities. This document was developed to provide guidance

to those radioanalytical laboratories that will support EPA’s response and recovery actions following

a radiological or nuclear incident of national significance (INS).

The need to ensure adequate laboratory infrastructure to support response and recovery actions

following a major radiological incident has been recognized by a number of federal agencies. The

Integrated Consortium of Laboratory Networks (ICLN), created in 2005 by 10 federal agencies1,

consists of existing laboratory networks across the Federal Government. The ICLN is designed to

provide a national infrastructure with a coordinated and operational system of laboratory networks

that provide timely, high quality, and interpretable results for early detection and effective

consequence management of acts of terrorism and other events requiring an integrated laboratory

response. It also designates responsible federal agencies (RFAs) to provide laboratory support across

response phases for chemical, biological, and radiological agents. To meet its RFA responsibilities

for environmental samples, EPA has established the Environmental Response Laboratory Network

(ERLN) to address chemical, biological, and radiological threats. For radiological agents, EPA is the

RFA for monitoring, surveillance, and remediation, and will share responsibility for overall incident

response with the U.S. Department of Energy (DOE). As part of the ERLN, EPA’s Office of

Radiation and Indoor Air is leading an initiative to ensure that sufficient environmental

radioanalytical capability and competency exists to carry out EPA’s designated RFA responsibilities.

 This document presents three radioanalytical scenarios, responding to two different public health

questions, that address the immediate need to determine the concentration of known or unknown

radionuclides in air particulate samples. The scenarios are based upon the radionuclides that probably

would be released by a radiological dispersal device into the atmosphere. The first analytical scenario

assesses whether air particulate samples indicate immediate threats to human health, at identified

Protective Action Guides doses, and warrant implementation of protective measures specific to

radiation concerns. The second assesses the radionuclide content of samples subsequent to the initial

response phase and assesses radionuclide concentrations down to the lowest risk levels.

The third situation assumes that the radioactive contaminants are known, and a shortened version

of the first two analytical scenarios is used to help expedite the analysis process. Use of established

analytical schemes will increase the laboratory efficiency so that large numbers of samples can be

analyzed in a timely manner. The use of the analytical schemes and the associated measurement

quality objectives also will ensure that the radioanalytical data produced will be of known quality

appropriate for the intended incident response decisions.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

ii

As with any technical endeavor, actual radioanalytical projects may require particular methods or

techniques to meet specific measurement quality objectives. The document cannot address a

complete catalog of analytical methodologies or potential radionuclides. Radiochemical methods to

support response and recovery actions following a radiological or nuclear INS can be found in

Standardized Analytical Methods for Environmental Restoration Following Homeland Security

Events, Revision 4.0.

Detailed guidance on recommended radioanalytical practices may be found in the Multi-Agency

Radiological Laboratory Analytical Protocols Manual (MARLAP) referenced in this document.

Familiarity with Chapters 2 and 3 of MARLAP will be of significant benefit to the users of this

guide.

This document is one in a planned series designed to present radioanalytical laboratory personnel,

Incident Commanders (and their designees), and other field response personnel with key laboratory

operational considerations and likely radioanalytical requirements, decision paths, and default data

quality and measurement quality objectives for samples taken after a radiological or nuclear incident,

including incidents caused by a terrorist attack. Documents currently completed or in preparation

include:

! Radiological Laboratory Sample Analysis Guide for Incidents of National Significance –

Radionuclides in Water (EPA 402-R-07-007, January 2008) 

! Radiological Laboratory Sample Analysis Guide for Incidents of National Significance –

Radionuclides in Air (EPA 402-R-09-007, June 2009)

! Radiological Laboratory Sample Screening Analysis Guide for Incidents of National

Significance (EPA 402-R-09-008, June 2009)

! Method Validation Guide for Qualifying Methods Used by Radiological Laboratories

Participating in Incident Response Activities (EPA 402-R-09-006, June 2009) 

! Guide for Radiological Laboratories for the Identification, Preparation, and Implementation of

Core Operations for Radiological Incident Response (in preparation)

! Guide for Radiological Laboratories for the Control of Radioactive Contamination and

Radiation (in preparation)

! Radiological Laboratory Sample Analysis Guide for Incidents of National Significance –

Radionuclides in Soil (in preparation)

Comments on this document, or suggestions for future editions, should be addressed to:

Dr. John Griggs

U.S. Environmental Protection Agency

Office of Radiation and Indoor Air

National Air and Radiation Environmental Laboratory

540 South Morris Avenue

Montgomery, AL 36115-2601

(334) 270-3450

Griggs.John@epa.gov
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

iii

Acknowledgments

This manual was developed by the National Air and Radiation Environmental Laboratory (NAREL)

of EPA’s Office of Radiation and Indoor Air (ORIA).

Dr. John Griggs served as project lead for this document. Several individuals provided valuable

support and input to this document throughout its development. Special acknowledgment and

appreciation are extended to Dr. Keith McCroan, ORIA/NAREL; Mr. Daniel Mackney for his

support in instrumental analysis, ORIA/NAREL; Ms. Lindsey Bender, ORIA/Radiation Protection

Division (RPD); Dr. Lowell Ralston and Mr. Edward Tupin, CHP, both of ORIA/RPD; Ms. Schatzi

Fitz-James, Office of Emergency Management, Homeland Security Laboratory Response Center;

and Mr. David Garman, ORIA/NAREL. We also wish to acknowledge the external peer reviews

conducted by Carolyn Wong, David Burns, and Sherrod Maxwell, whose thoughtful comments

contributed greatly to the understanding and quality of the report. Numerous other individuals both

inside and outside of EPA provided peer review of this document, and their suggestions contributed

greatly to the quality and consistency of the final document. Technical support was provided by Dr.

N. Jay Bassin, Dr. Anna Berne, Dr. Carl V. Gogolak, Dr. Robert Litman, Dr. David McCurdy, and

Mr. Robert Shannon of Environmental Management Support, Inc.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

iv

Contents

Acronyms, Abbreviations, Units, and Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

Radiometric and General Unit Conversions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

I. INTRODUCTION ..........................................................1

A. Purpose and Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

B. Scope of Radiological Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

C. Relationship of PAG, AAL, ADL, Risk Levels, and uMR ..........................5

D. Analytical Response Time .................................................8

E. Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

F. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

II. RADIONUCLIDES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

III. DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

A. Sampling and Processing at the Laboratory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

B. Discrete Radioactive Particles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

C. Sampling for Iodine and Tritium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

D. Crosswalk of Data Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

IV. SCENARIO 1 (Identifying Air Samples with Highest Activities) . . . . . . . . . . . . . . . . . . . . 21

Notes to Scenario 1: High-Flow Air Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

V. SCENARIO 2 (Priority to Air Samples with Highest Activities) . . . . . . . . . . . . . . . . . . . . . . 33

Notes to Scenario 2: Low-Flow Air Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

VI. SCENARIO 3 (Radionuclides in Air Particulate Samples Have Been Identified) . . . . . . . . 42

Notes for Scenario 3: Contaminating Radionuclides Known . . . . . . . . . . . . . . . . . . . . . . . . 43

APPENDIX I. Tables of Radioanalytical Parameters for Radionuclides of Concern . . . . . . . . . 47

APPENDIX II. Example of High-Concentration Air Particulates (Radioanalytical Scenario 1) 53

Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Event Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Analysis Paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

APPENDIX III. Example of Air Particulate Filters Contaminated at Less than 2 rem (Radioanalytical

Scenario 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Event Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Analysis Paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

APPENDIX IV. Example of Air Particulate Filters With Known Radiological Contaminants

(Radioanalytical Scenario 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

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Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Event Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Analysis Paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

APPENDIX V. Representative Analytical Processing Times . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

APPENDIX VI. Establishing DQOs and MQOs for Incident Response Analysis . . . . . . . . . . . 70

APPENDIX VII. Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Figures

Figure 1 – Air Sample Scenarios and Response Phases ................................4

Figure 2 – Air Scenario 1 Analytical Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Figure 3 – Air Scenario 2 Analytical Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Figure 4 – Air Scenario 3 Analytical Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Figure 5 – Approximate Timeframe for Radiochemical Analyses (Radioanalytical Scenario 1) 66

Figure 6 – Approximate Timeframe for Radiochemical Analyses (Radioanalytical Scenario 2) 67

Figure 7 – Approximate Timeframe for Radiochemical Analyses (Radioanalytical Scenario 3) 68

Figure 8 – A Decision Point in a Flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Figure 9 – The Data Quality Objectives Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Figure 10 – Example Illustrating Case (a). Baseline Condition (null hypothesis): Parameter Exceeds

the Analytical Action Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Figure 11 – Example Illustrating Case (b). Baseline Condition (null hypothesis): Parameter Does Not

Exceed the Analytical Action Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Tables

Table 1 – Analytical Response Responsibilities ......................................4

Table 2 – Relationship Among Dose, AAL, ADL, and uMR ..............................7

Table 3 – Radionuclides of Concern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Table 4 – Crosswalk of PAG, AAL, ADL, and uMR Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Table 5 – Radionuclides with Low-Abundance Gamma Rays . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Table 6 – Beta “Only” Emitters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Table 7A – Analytical Decision Levels (ADL) and Required Method Uncertainty Using Gross Alpha

Screening Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Table 7B – Analytical Action and Decision Levels (AAL and ADL) and Required Method

Uncertainty Using Gross Beta-Gamma Screening Methods . . . . . . . . . . . . . . . . . . . . . . . . . 48

Table 7C – Analytical Action and Decision Levels (AAL and ADL) and Required Method

Uncertainty Using Alpha Radionuclide Specific Methods . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Table 7D – Analytical Action and Decision Levels (AAL and ADL) and Required Method

Uncertainty Using Beta-Gamma Radionuclide-Specific Methods . . . . . . . . . . . . . . . . . . . . 50

Table 8A – Analytical Action and Decision Levels (AAL and ADL) and Required Method

Uncertainty at 10–4 and 10–6 Risk Using Alpha Radionuclide-Specific Methods . . . . . . . . . 51
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

vi

Table 8B – Analytical Action and Decision Levels (AAL and ADL) and Required Method

Uncertainty at 10–4 and 10–6 Risk Using Beta-Gamma Radionuclide-Specific Methods . . . . 52

Table 9 – Air Monitoring: Air Filter Counting Times for Various PAGs and Sampling Rates and

Durations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Table 10A – The DQO Process Applied to a Decision Point . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Table 10B – Possible Decision Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Table 10C – The DQO Process Applied to a Decision Point . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Table 10D – Values of z1-α (or z1–β) for Some Commonly Used Values of α (or β) . . . . . . . . . . . 74

Table 11A – DQOs and MQOs for Radioanalytical Scenario 1. Laboratory Prioritization Decisions

Based on Screening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Table 11B – DQOs and MQOs for Scenario 1. Values Reported to the Incident Commander Based

on Radionuclide-Specific Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Table 12A – DQOs and MQOs for Radioanalytical Scenario 2. Laboratory Prioritization Decisions

Based on Screening (Gross α, β, or γ Measurements) and 131I . . . . . . . . . . . . . . . . . . . . . . . . 78

Table 12B – DQOs and MQOs for Scenario 2. Values Reported to the Incident Commander Based

on Radionuclide-Specific Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

Table 13 – DQOs and MQOs for Scenario 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Table 14 – Estimated Counting Times for a Filter Sample Analyzed on a Gas Proportional Counter

To Reach an Alpha Detection Limit and a 10% Count Rate Uncertainty for Low- and HighVolume Air Samples at 500-mrem AAL Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

vii

Acronyms, Abbreviations, Units, and Symbols

(Excluding chemical symbols and formulas)

α . . . . . . . . . . . alpha particle

α . . . . . . . . . . . probability of a Type I decision error

AAL . . . . . . . . analytical action level

ADL . . . . . . . . analytical decision level

AL . . . . . . . . . action level

AS . . . . . . . . . alpha spectrometry

β . . . . . . . . . . . beta particle

β . . . . . . . . . . . probability of a Type II decision error

Bq . . . . . . . . . . becquerel (1 dps)

CERCLA . . . . Comprehensive Environmental Response, Compensation, and Liability Act of 1980

(“Superfund”)

cfm . . . . . . . . . cubic feet per minute

CFR . . . . . . . . Code of Federal Regulations

cm . . . . . . . . . . centimeter

COC . . . . . . . . chain of custody

cpm . . . . . . . . . counts per minute

d . . . . . . . . . . . day

DAC . . . . . . . . derived air concentration

DCF . . . . . . . . Dose Conversion Factor

DL . . . . . . . . . discrimination limit

DOE . . . . . . . . United States Department of Energy

DP . . . . . . . . . decay product(s)

dpm . . . . . . . . disintegration per minute

dps . . . . . . . . . disintegration per second

DQO . . . . . . . . data quality objective

DRP . . . . . . . . discrete radioactive particle

e– . . . . . . . . . . . electron

Eβmax . . . . . . . . maximum energy of the beta-particle emission

EDD . . . . . . . . electronic data deliverable

ERLN . . . . . . . Environmental Response Laboratory Network

EPA . . . . . . . . United States Environmental Protection Agency

γ . . . . . . . . . . . gamma ray

g . . . . . . . . . . . gram

Ge . . . . . . . . . . germanium [semiconductor]

GM . . . . . . . . . Geiger-Muller [detector]

GP . . . . . . . . . gas proportional 

GPC . . . . . . . . gas proportional counting/counter

GS . . . . . . . . . gamma spectrometry

Gy . . . . . . . . . . gray

h ........... hour

H0 . . . . . . . . . . null hypothesis

H1 . . . . . . . . . . alternate hypothesis

HF . . . . . . . . . hydrofluoric acid
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

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HPGe . . . . . . . high-purity germanium [detector]

IC . . . . . . . . . . Incident Commander

ICC . . . . . . . . . Incident Command Center

ICLN . . . . . . . Integrated Consortium of Laboratory Networks 

ICRP . . . . . . . . International Commission on Radiological Protection

IND . . . . . . . . . improvised nuclear device (i.e., a nuclear bomb)

INS . . . . . . . . . incident of national significance

keV . . . . . . . . . kilo (thousand) electron volts

L ........... liter

LBGR . . . . . . . lower bound of the gray region

LEPD . . . . . . . low-energy photon detector

LS . . . . . . . . . . liquid scintillation

LSC . . . . . . . . liquid scintillation counter/counting

MARLAP . . . . Multi-Agency Radiological Laboratory Analytical Protocols Manual

MARSSIM . . . Multi-Agency Radiation Survey and Site Investigation Manual

MeV . . . . . . . . mega (million) electron volts

mg . . . . . . . . . milligram (10–3 g)

mL . . . . . . . . . milliliter (10–3 L)

mrem . . . . . . . millirem (10–3 rem)

μg . . . . . . . . . . microgram (10–6 g)

MDC . . . . . . . minimum detectable concentration

min . . . . . . . . . minute

MQO . . . . . . . measurement quality objective

NaI(Tl) . . . . . . thallium-activated sodium iodide detector

NORM . . . . . . naturally occurring radioactive materials

nMR . . . . . . . . . required relative method uncertainty

PAG . . . . . . . . protective action guide

pCi . . . . . . . . . picocurie (10–12 Ci)

QA . . . . . . . . . quality assurance

QC . . . . . . . . . quality control

rad . . . . . . . . . radiation absorbed dose

RDD . . . . . . . . radiological dispersal device (i.e., “dirty bomb”)

RDL . . . . . . . . required detection limit

REGe . . . . . . . reverse electrode germanium [detector]

RFA...............responsible federal agency

rem . . . . . . . . . roentgen equivalent man

s . . . . . . . . . . . second

SI . . . . . . . . . . International System of Units

SOP . . . . . . . . standard operating procedure

Sv . . . . . . . . . . sievert

TAT . . . . . . . . turnaround time

TEDA . . . . . . . triethylenediamine

TEDE . . . . . . . total effective dose equivalent

UBGR . . . . . . upper bound of the gray region

uMR . . . . . . . . . . required method uncertainty

y . . . . . . . . . . . year
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

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Radiometric and General Unit Conversions

To Convert To Multiply by To Convert To Multiply by

years (y) seconds (s)

minutes (min)

hours (h)

days (d)

3.16 × 107

5.26 × 105

8.77 × 103

3.65 × 102

s

min

h

d

y 3.17 × 10–8

1.90 × 10–6

1.14 × 10–4

2.74× 10-3

disintegrations

per second (dps)

becquerels (Bq) 1 Bq dps 1

Bq

Bq/kg

Bq/m3

Bq/m3

picocuries (pCi)

pCi/g

pCi/L

Bq/L

27.0

2.70 × 10–2

2.70 × 10–2

10–3

pCi

pCi/g

pCi/L

Bq/L

Bq

Bq/kg

Bq/m3

Bq/m3

3.70 × 10–2

37.0

37.0

103

microcuries per

milliliter

(μCi/mL)

pCi/L 109 pCi/L μCi/mL 10–9

disintegrations

per minute (dpm)

μCi

pCi

4.50 × 10–7

4.50 × 10–1

pCi dpm 2.22

cubic feet (ft3

) cubic meters

(m3)

2.83×10–2 cubic meters

(m3)

cubic

feet (ft3)

35.3

gallons (gal) liters (L) 3.78 liters gallons 0.264

gray (Gy) rad 102 rad Gy 10–2

roentgen equivalent man (rem)sievert (Sv) 10–2 Sv rem 102

NOTE: Traditional units are used throughout this document instead of International System of Units

(SI) units. Protective Action Guides (PAGs) and their derived concentrations appear in official

documents in the traditional units and are in common usage. Conversion to SI units will be aided by

the unit conversions in this table. Conversions are exact to three significant figures, consistent with

their intended application.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

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 The sum of the effective dose equivalent (for external exposure) and the committed effective dose equivalent (for

internal exposure). TEDE is expressed in units of sievert (Sv) or rem.

2

 The common unit for the effective or “equivalent” dose of radiation received by a living organism, equal to the actual

dose (in rads) multiplied by a factor representing the danger of the radiation. “Rem” stands for “roentgen equivalent

man,” meaning that it measures the biological effects of ionizing radiation in humans. One rem is equal to 0.01 Sv.

1

I. INTRODUCTION

This guide deals with the analysis of air samples that may have been contaminated as the result of

a radiological or nuclear event, such as a radiological dispersal device (RDD), improvised nuclear

device (IND), or an intentional release of radioactive materials into the atmosphere via mechanical

or other methods. In the event of a major incident that releases radioactive materials to the

environment, EPA will turn to selected radioanalytical laboratories to support its response and

recovery activities. In order to expedite sample analyses and data feedback, the laboratories will need

guidance on EPA’s expectations. 

A response to a radiation release to the environment likely will occur in three phases: “early,”

“intermediate,” and “recovery.” Each phase of an incident response will require different and distinct

radioanalytical resources to address the different consequences, management, priorities, and

requirements of each phase. Some of the more important radioanalytical laboratory responsibilities

germane to an incident response consist of:

• Radionuclide identification and quantification,

• Sample load capability,

• Sample processing turnaround time,

• Quality of analytical data, and

• Data transfer capability.

The early phase begins at the initial event and lasts for three or four days, during which data are

scarce and pre-planned dispersion models may be used when appliable. During this phase,

responders are primarily concerned about evacuating people, sheltering them in place, or restricting

exposure to ambient air and dust. The purpose of the actions and evaluations taken during the early

phase is to minimize exposure and to prevent acute health effects. The Protective Action Guides

(PAGs) for radiological emergencies recommend evacuation of a population if the projected shortterm total effective dose equivalent1

 (TEDE) exceeds 1 rem.2 The nominal trigger for sheltering is

1-rem over four days (projected avoided inhalation dose). The radioanalytical resource requirements

(field or fixed laboratory) for this early phase may vary significantly depending on the time frame,

source-term nuclide (see glossary), and the extent of the contamination. 

The intermediate phase begins when no more radiation releases are expected, and the source term

contamination radionuclides have been qualitatively identified. In this phase, radionuclide concentrations, extent of the contaminated zone, and matrices (air, water, soil) required for analysis may not

be well defined. The radioanalytical resources needed will depend on the radionuclide analytical

action level (AAL) developed for the various media important to human exposure. The AAL may

change depending upon the stage of the event, the appropriate PAGs, or risk values. The radionuclide

AALs (derived concentrations) for different media types are based on the PAGs or risk values. For
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

3

 Throughout this guide, the term “Incident Commander” (or “IC”) includes his or her designee. 

4

 Eckerman et al.(1999), EPA (2002), ICRP (1995, 1996) 

2

the intermediate phase, PAGs have been established to limit the projected radiation doses for

different exposure periods: not to exceed 2-rem TEDE over the first year, 500-mrem TEDE during

the second year, or 5 rem over the next 50 years (including the first and second years of the incident).

In addition, radionuclide concentration limits for food and water as regulated by the Food and Drug

Administration and EPA would be applicable.

The final, or “recovery,” phase occurs as part of a radiological incident site-remediation effort.

During this phase, when site atmospheric characterization and remediation cleanup effectiveness are

determined, there is a potential for more extensive radiochemical analyses at the lowest radionuclide

concentrations. Airborne radionuclide concentrations therefore should be compared to derived air

concentrations (DACs) corresponding to 10–4 and 10–6 lifetime cancer morbidity risk factors for longterm exposures.

During all phases of an incident response, radioanalytical resources are needed for identifying the

radionuclide source term and quantification of the radionuclides in a variety of sample media.

Additionally, gross screening of samples to prioritize sample processing or to obtain information

related to the general level of contamination in samples is also necessary. This guide has been

developed to provide the Incident Commander (IC)3 and the laboratories used during an incident with

a logical processing scheme to prioritize sample processing in relation to the radionuclide air

concentrations corresponding to established PAGs or risk levels.

A. Purpose and Objectives

This document is intended to assist those analytical laboratories that will be called upon to provide

rapid support to field personnel and decision makers following a radiological release to the

atmosphere. Because EPA recognizes that in the early and intermediate period following such a

release there may not be sufficient time for the Incident Command Center (ICC) to coordinate and

communicate complete measurement quality objectives and analytical priorities to the laboratory,

this document will enable laboratories to proceed with a consistent approach to developing and

reporting data suitable for the anticipated use.

The ultimate purpose of the screening process described in this guide is to ensure that laboratories

can adequately respond to the Incident Commander’s requirements with timely analytical results so

that public health is protected. The recommendations in this guide are based upon EPA’s PAGs and

risk factors for radionuclides in air.4

 The PAGs and risk factors are converted to air concentrations

for individual radionuclides based on the decay particle, its energy, and inhalation/residence time

dose models for a standard person. 

Analytical action levels (AALs) are derived radionuclide-specific activity concentrations in air that

correspond to specific EPA PAG dose limits or acceptable Agency risk levels. In this document,

EPA uses AALs to prioritize air filter samples for radiochemical analyses. Subsection C, on page
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

3

5, describes the methods and assumptions EPA

uses to calculate AALs for the radionuclides

discussed in this document.

One of the key objectives in this document is

to explain the responsibilities indicated above

in terms of analytical processes. While the IC

should provide the necessary information

(analytes, matrices, measurement quality

objectives) that define the scope of the

laboratory’s processing requirements and

results, the laboratory should ensure that the

methods used have been validated and will

meet the desired measurement quality objectives (MQOs) and the required turnaround

time. In the event that laboratories receive

samples without complete documentation or

direction, laboratories may follow the procedures and examples in this document and be

confident that their analyses will provide

reasonable and consistent results.

This document is not meant to replace any

field monitoring decisions on sample prioritization. It is intended as a guide for how to

establish priorities for samples received at the

laboratory at different times throughout the

response, and it should provide to the IC the

basis for understanding the nature and limitations of the data received from the laboratories.

B. Scope of Radiological Scenarios

Radiological events can be subdivided into

three phases, which are generally defined in

this document as: early (onset of the event to

about day 4), intermediate (about day 4 to

about day 30), and recovery (beyond about day

30). This guide concentrates on the time from

the end of the early phase, through the

intermediate phase, and into the recovery

phase. During the early phase, analytical

priorities need to address the protection of the

public and field personnel due to potentially

high levels of radioactivity and to provide for

qualitative identification of radionuclides.

Action Levels: AALs and ADLs

This guide relies heavily on the use of the terms “analytical

action level” (AAL), “required method uncertainty” (uMR),

and “analytical decision level” (ADL) in characterizing the

desired levels of performance of analytical methods and the

radioanalytical results for use in decisions.

The term “analytical action level” (AAL) is used as a general

term denoting the radionuclide concentration at which action

must be taken by incident responders. The AAL will

correspond to a PAG value (short-term dose-based) or a riskbased value (related to long-term health effects). Ideally, the

Incident Commander (IC) will provide the laboratory with

the dose- or concentration-based action level and the

acceptable decision error rates. If not, this guide provides

“default”values. For example, the air concentration of 226Ra

corresponding to the 500-mrem PAG is 1.8 pCi/m3

. Tables

7A, 7B, 7C, and 7D show the AALs associated with the 2-

rem, 500-mrem, 10–4 risk and 10–6 risk values for selected

alpha, beta, and gamma-emitting radionuclides. Incidentspecific action levels different from the ones used in the

tables may be promulgated. In these cases, the corresponding

AALs can be calculated as a linear function of either the 500-

mrem AALs or the 10–4 or 10–6 risk values (see Scenario 3

for an example of an event-specific AAL calculated in this

manner).

The selection, validation, and execution of a particular

analytical method rely on the ability of that method to

produce a result with the specified uncertainty, uMR, at the

AAL. These conditions assure that the quality of the final

sample analysis data will be adequate for making critical

decisions. Whenever the reported sample activity or concentration exceeds a pre-defined decision level (the ADL),

appropriate action is warranted. The derivation and use of

AAL, uMR, and ADL are discussed in detail throughout this

guide. While closely interrelated, it is important to note that

the use of AAL (and associated uMR) and ADL represent

distinct concepts; they may not be used interchangeably but

rather should be interpreted and applied according the

guidelines of this document. 

The required method uncertainty and ADL will change

depending upon the acceptable decision error rate. Tables

provided in Appendix I list the AAL, ADL, and uMR values

for the radionuclides of concern. The tables present gross

screening and radionuclide-specific measurements for alpha

and beta/gamma-emitting radionuclides. Derivation of the

ADL values for each of these tables can be found in

Appendix VI. The listed AALs are applicable as default

values based on generic conversions of the dose level to

concentration in air for a specific radionuclide. The IC may

provide incident-specific action levels or decision error rates

that would supersede these values. In this case, the laboratory

will need to develop new tables for all values, using the

process described in Appendix VI.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

4

During the intermediate phase, the radionuclides and matrices of concern are known qualitatively,

and the quantitative levels suitable for making decisions based on action levels need to be

determined rapidly. The time period of an incident where this document will find its greatest utility

is early in the intermediate phase through the end of the recovery phase. Laboratories performing

analyses must optimize sample processing and rapid delivery of sample results to permit assessment

in a timely manner of whether or not AALs have been exceeded. During the recovery phase, the

screening techniques used for samples will be less significant because the radionuclides from the

event are likely to have been characterized already. This is represented by the lower portions of the

flowcharts, which address analyses of specific radionuclides. 

This document presents three analytical scenarios to aid laboratories in establishing priorities for

analyzing samples received during the response to a radiological release. The first two assume that

the radioactive material is unknown. Table 1 summarizes the relevant responsibilities of the IC and

the laboratory manager during such a response, and Figure 1 depicts how they relate to the response

team’s needs for sample prioritization.

TABLE 1 – Analytical Response Responsibilities

Information

Provided...

Sample

Priority

Method

Uncertainty

DQOs/

 MQOs

Reporting 

(Results,

Anomalies)

Analyte 

Selection

Sampling Specs

(Time, Volume)

Hot

Particles

Turnaround

Time 

Compliance

Filter

Media

Procedure

Selection

By: IC IC IC Lab IC* IC Lab Lab IC Lab

To: Lab Lab Lab IC Lab Lab IC IC Lab IC

*

During the early phase, the laboratory will identify the radionuclides present. Once it is determined which radionuclides are present, the IC may

decide analytical priorities.

Early Phase Intermediate Phase Recovery Phase

Sample 

priority based on

concentration

Low priority*

High priority*

Gross quantification

of activity at 

2 rem and 500 mrem

Radionuclidespecific

identification

Radioanalytical

Scenario 2 

Radionuclides characterized

(Radioanalytical Scenario 3)

Priority set

by IC

?

Yes,

but priority set

low* by IC

No, and

activity is

Low

Yes, and priority set

high* by IC

Radioanalytical

Scenario 3

Determination of 

radionuclides >10–4 risk level

Determination of

radionuclides < 10–6

risk level

High priority*

Low priority*

Day 3 Following Event Weeks to Months Following Event

*Note: ”High” and “Low”

refer to processing

priorities, not activity

Unknown

radionuclides?

(Scenario 1)

Yes No

Figure 1 – Air Sample Scenarios and Response Phases
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

5

• In Radioanalytical Scenario 1, the identity of the radionuclides and potential concentrations are

unknown. This is most likely to occur during the early phase of the event. The laboratory’s

priority is to identify all the radionuclides present and their air concentrations. Air particulate

samples (filters) and aerosol samples (canisters, see page 19), taken from an area in the vicinity

of the radiological event, are suspected to be highly contaminated with an unknown quantity of

yet unidentified radionuclides. The radionuclide identities and concentrations taken from various

analyses will be compared to the 2-rem and 500-mrem AAL values, giving priority to the highest

activity samples. MQOs for these AALs can be met with smaller volume air samples than

normal, allowing shorter sampling times.

• The second scenario (Radioanalytical Scenario 2) addresses the need to identify areas of

acceptable air quality and will occur later in the intermediate phase and into the recovery phase.

This scenario requires the laboratory to determine whether identified or partially identified

airborne radionuclide concentrations are above the 500-mrem AAL value or correspond to

concentrations in the 10!4

 to 10!6 risk levels. Decisions regarding priority are based on EPA’s

PAGs or risk factors. Samples with concentrations corresponding to the 10–4 and 10–6 risk-based

factors are of lower analytical priority at this time.

• Radioanalytical Scenario 3 is where the radionuclides have been identified, and this scenario

would normally occur during the intermediate/recovery phase. This scenario is focused on

assessing air-particulate filters that have concentrations below an associated 10!4 long-term risk

factor. So while Figure 1 depicts Scenario 3 occurring during the later intermediate phase,

Scenario 3 could occur earlier, in which case the laboratory need not waste analytical processing

time trying to identify which radionuclides are present. The flow focuses on establishing the

priority for processing samples based on the gross concentration screening values for the specific

radionuclides. Formal evaluation of other naturally occurring radionuclides may be necessary

when assessing the long-term risks of the sampled aerosol. In the later phases, sample input from

Radioanalytical Scenario 1 or 2 flow schemes (as is the case for Scenario 2) is not anticipated.

These scenarios may be applicable in different phases of the event, although as was previously

indicated, Scenario 1 is usually the early phase, and Scenario 2 is the late-intermediate to recovery

phase. The flow charts (Figures 2–4) assume that the laboratory already has acquired or developed

the general guidance discussed for each scenario. However, laboratories should note that at any time

samples may be assigned a specific priority based on the status or phase of the incident.

Samples that may become evidence in a criminal investigation must be handled separately

(particularly with respect to chain of custody), and the laboratory should receive information form

the Incident Commander or lead law-enforcement agency on how to process these samples.

C. Relationship of PAG, AAL, ADL, Risk Levels, and uMR

PAGs reflect the limits of dose that are allowed to be received by individuals during different phases

of an incident. Because laboratories will determine sample concentrations in pCi/m3, AALs (see

Tables 7A–7D) are action levels expressed in units of pCi/m3

 that equate to PAG annual dose limits

of 2 rem (first year) and 500 mrem (second year). These are based on:
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

6

• Maximum inhalation dose coefficients (DCFs) (in units of Sv/Bq) taken from ICRP

Publication 72 (ICRP 1996) or from Federal Guidance Report 13 CD Supplement (EPA

2002). From among the coefficients listed for each radionuclide for lung clearance

classifications of fast (F), medium (M), and slow (S), EPA chose the coefficient that gave

the largest or maximum committed effective dose per unit intake for the adult member of the

public. Dose coefficients in Sv/Bq were converted to units of mrem/pCi by multiplying by

a conversion factor of 3,700.

• An exposure duration of 1 year (365 days).

• An inhalation rate of 22.1 m3

/d taken from ICRP Publication 66 (ICRP 1995) for an adult

member of the public.

Accordingly, PAG-derived AALs are calculated for each radionuclide according to the following

equation:

AAL (pCi/m3

) = PAG / (DCF × 22.1 m3/d × 365 d/y)

For example, the AAL for 241Am corresponding to the 2000 mrem/y dose limit is calculated as:

AAL 241Am = 2000 mrem/y / (0.36 mrem/pCi × 22.1 m3/d × 365 d/y)

= 0.7 pCi/m3

Action levels can be either risk-based or dose-based. Risk-based AALs (Tables 8A and 8B) are

expressed in units of pCi/m3

 that equate to EPA’s acceptable lower and upper cancer risk levels for

cleanup, namely 1 in 1 million (1×10!6) and 1 in 10,000 (1×10!4). These are based on:

• Maximum inhalation risk coefficients (in units of Sv/Bq) taken from Federal Guidance

Report 13 (Eckerman et al., 1999) or from Federal Guidance Report 13 CD Supplement

(EPA 2002). From among the coefficients listed for each radionuclide for lung clearance

classifications of fast (F), medium (M), and slow (S), EPA chose the coefficient that gave

the largest or maximum lifetime, age-averaged, excess morbidity (total cancer) risk per unit

intake. Risk coefficients in Risk/Bq were converted to units of Risk/pCi by dividing by the

conversion factor of 27.027.

• An exposure duration of 1 year (365 days)

• An inhalation rate of 22.1 m3

/y taken from ICRP Publication 66 (ICRP 1995) for an adult

member of the public.

Accordingly, risk-based AALs are calculated for each radionuclide according to the following

equation:

AAL (pCi/m3

) = Risk Level / (Risk coeff. × 22.1 m3/d × 365 d/y)

For example, the AAL for 241Am corresponding to the 10!4 risk level is calculated as:

AAL 241Am = 1×10!4 risk / (3.8×10!8 risk/pCi × 22.1 m3/d × 365 d/y)

= 0.33 pCi/m3.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

5

 Appendix VI provides the derivation and detailed discussion of MQOs, required method uncertainties, and ADLs. 

6

 See Tables 7A–7D for 2-rem and 500-mrem AALs and Tables 8A and 8B for risk-based AALs.

7

 Tables 7A and 7B summarize default ADLs and uMR for gross screening measurements at 2 rem and 500 mrem. Tables

7C and 7D summarize default ADLs and uMR for radionuclide-specific measurements at 2 rem and 500 mrem.

8

 Tables 8A and 8B summarize ADLs and uMR for radionuclide-specific measurements at 10–4 and 10–6 risk levels.

7

 Decisions related to the processing and prioritization of specific samples will be made by laboratory

personnel at the laboratory by comparing the results of radioanalytical measurements to “analytical

decision level” (ADL) concentrations. Whenever the measured analyte concentration equals or

exceeds the applicable ADL concentration, it will be concluded that the AAL (PAG or risk factor)

has been exceeded. The ADL concentrations are always less than the corresponding AAL values by

an interval calculated to provide statistical confidence when deciding whether the corresponding

AAL has or has not been exceeded. The magnitude of this interval corresponds to the maximum

uncertainty that would be consistent with acceptable decision error rates established during the data

quality objective (DQO)/MQO process.5

 This uncertainty is referred to as the required method

uncertainty, uMR, and is defined in MARLAP.

MQOs are statements of performance objectives or requirements for selected method performance

characteristics. Method performance characteristics include the method uncertainty, the method’s

detection capability, the method’s quantification capability, the method’s range, the method’s

specificity, and the method’s ruggedness. An example MQO for the method uncertainty at a specified

concentration, such as the action level, could be: 

“A required method uncertainty for 226Ra of 2.1 pCi/m3

 or less at the analytical action

level of 7.0 pCi/m3 for screening methods of analysis.”

Table 2 provides examples of a dose and its corresponding AAL, ADL, and required method

uncertainty (uMR) for 226Ra. Note that there are differences in these values not only based on the dose

or risk, but also on whether or not a screening instrument or radiochemical-specific methods are

used. 

TABLE 2 – Relationship Among Dose, AAL, ADL, and uMR for 226Ra

Measurement Type

Dose

(mrem) or

Risk-Based

Value

AAL6

(pCi/m3)

ADL*

(pCi/m3)

uMR

(pCi/m3)

Screening7 2,000 7.0 3.5 2.1

RadionuclideSpecific2,000 7.0 4.9 0.88

RadionuclideSpecific(at 10–4 risk)8 0.44 0.31 0.055

*ADL values are calculated per equations in Appendix VI
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

8

The values in the tables in Appendix I are calculated based on tolerable Type I and Type II error rates

for each measurement type as described in Appendix VI.

Laboratories will perform both gross activity measurements and radionuclide-specific measurements

during an incident. Because different DQOs and MQOs are applicable to different types of measurements, different uMR and the corresponding ADL values are provided for screening and radionuclidespecific analyses. The values for uMR and corresponding ADL for screening and radionuclide-specific

determinations presented in Tables 7A–D, 8A, and 8B (Appendix I) provide laboratories with a

starting point for developing methods and systems for recovery activities. It is anticipated that

incident-specific DQOs and MQOs may be developed by the IC and provided to the laboratory.

Once the radionuclides are identified, the focus of response activities will shift to assessment of

dispersion, habitability, and long-term health effects. This is the focus of the second scenario, and

again the laboratory’s main job will be to prioritize the order of sample analysis based on activity.

It should be noted that, during the intermediate and recovery phases, resuspension of particulates

during remediation may cause airborne radionuclide concentrations to increase. Thus, one cannot

assume that all radionuclide concentrations on air particulate filters will decrease as the event

progresses. Continued sample screening will help provide the laboratory staff with accurate

information regarding activity on the filters.

The attached charts and accompanying numbered notes and data tables depict the anticipated

analytical flow that will assist the lab to respond rapidly and consistently. In keeping with concepts

of the Multi-Agency Radiological Laboratory Analytical Protocols Manual (MARLAP) , this guide

does not specify analytical methods. A performance-based approach for the selection of appropriate

analytical methods by the laboratory will be used to achieve MQOs specified by this document and

incident responders.

The MQOs and any other analytical requirements serve as the basis for the laboratory’s selection of

a method under a performance-based approach. The laboratory should have method validation and

performance data to demonstrate the method’s ability to achieve the project-specific MQOs.

This document presents a default set of MQOs. Actual MQOs, however, always will depend upon

events and may need to be modified by incident responders and project planners to better address

a particular event. However, in order to have an analytical approach in place to address a variety of

incident scenarios, the identified decision points in the accompanying flow diagrams refer to the

default MQOs. The important MQO is the required method uncertainty at the AAL, which together

with the acceptable decision error rates, is used to establish the ADL. At most decision points in the

diagram, the decision is related to the ADL based on either PAG values or risk-based values. 

D. Analytical Response Time

Decisions regarding the extent of air contamination will need to be made in a timely manner.

Approximate times required for laboratory processing of these samples and finalizing the sample

results are shown in Appendix V for each radioanalytical scenario. They identify the workflow for

making qualitative and quantitative measurements of high-activity contaminated air particulate

samples (Radioanalytical Scenario 1) and determine whether lower-concentration samples still
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

9

present longer-term risk (Radioanalytical Scenario 2). The information regarding sample radioactivity measurements also needs to be communicated vigorously to the IC so that decisions

regarding movement of population, sheltering, other protective actions, or additional sampling can

be assessed accurately.

E. Implementation

It may be necessary for laboratories to incorporate key aspects of this document into their standard

operating procedures (SOPs). For example, the gross screening process will require specific

standards and response factors for each of the instruments used by the laboratory. This could be a

departure from the laboratory’s current screening practice because the activity levels, sample

geometries, and matrices may be significantly different from what the laboratory normally

experiences. Generally, it should be expected that higher activity tracers and QC standards may be

needed for the analysis of higher activity samples.

This guide focuses on the prioritization of sample analyses and some of the technical issues

encountered in performing analyses on air particulate samples received by the laboratory following

a radiological incident. The guidance on how to prepare and calibrate screening instruments for the

support of a radiological incident is outlined in Radiological Laboratory Sample Screening Analysis

Guide for Incidents of National Significance (EPA 402-R-09-007, June 2009). The guide describes

calibration and measurement techniques, instruments used for screening, and provides guidance on

interpretation of screening results.

Laboratories should become proficient with these procedures because they could be tasked to

respond to analytical requests in hours rather than weeks. Thus, laboratory personnel should become

familiar with the recommendations and procedures, and laboratories should conduct both training

and actual “drills” or exercises where analytical scenarios and samples are tested during a controlled

scenario. The frequency and depth of these exercises will be at the discretion of the laboratory

management.

Laboratory personnel also should be cross-trained in different areas of the incident response activities

listed below to help ensure continuity of sample analysis throughout the duration of the response and

cleanup: 

• Equipment calibration and QC checks

• Sample receipt and log-in

• Sample tracking and storage

• Screening

• Sample preparations

• Analytical separations

• Counting

• Contamination monitoring

• Report generation

• Data review

• Waste management
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

10

The scope of these activities may be different for incident response than for normal laboratory

operations. In order for the laboratories to be able to begin to process the samples promptly, certain

presumptive values are identified in the tables in this document for action levels, which may be

relied upon in the absence of explicit action levels received from the IC. However, these values may

change based on the needs of the particular event. MQOs will be stipulated by the IC and should be

communicated to the laboratory as early as possible so that analysis can meet project objectives.

For air monitoring, MQOs typically would be stated for analytical action levels. In most air

monitoring applications, it is impractical to specify an exact “standard” air volume that is passed

through an air particulate filter, or an iodine cartridge. The activity collected on an air filter (or

cartridge) will vary according to the sampling duration and flow rate. For operational practicality,

the analytical method and analysis time of the measurement should be adjusted to a “hypothetical

minimum” volume sampled so that the MQOs for an AAL can be met for all samples collected

(representing a batch) as long as the actual volume sampled for any sample is equal to or larger than

the “minimum” volume. The value of the “minimum volume” would be selected for a batch of

samples by evaluating the field sample submission form that contains the sample identifications and

corresponding total volumes sampled. For both gross screening and radionuclide-specific analyses,

most laboratories will standardize the counting time of a batch of samples to a single value, normally

the limiting counting time to meet the uMR at the AAL or a detection level. The flow diagram for

Scenario 1 (Figure 2) assumes a collected volume of 68 m3

, but volumes may be in the range of 3

to 100 m3. The analytical decision paths in Figure 3 (Scenario 2), which are based on discriminating

500-mrem AAL samples from10–4 and 10–6 risk levels, assume a collected volume of 200 to 1,600

m3

. Figure 4 (Scenario 3) outlines the flow path when the radionuclides are known. 

Once the appropriate method and the appropriate volume have been selected, the laboratory can

select the proper counting time and other parameters to meet the MQOs in the most efficient manner.

Presumably, the volume provided by the IC will exceed the minimum volume that a laboratory will

need when analyzing a batch of samples. It is also important for laboratories to be in contact with

the ICC regarding requirements for split samples and reserving aliquants of sample digestate for

additional analyses. This may require that more than the minimum volume is collected, that longer

counting times are specified, or that the laboratory has a procedure for splitting a sample before

starting analysis. The measurement uncertainty of the calculated air concentration from the sample

analyzed will be compared to the absolute and required relative method uncertainty.

Finally, it should be noted that laboratories that perform radiochemical analyses on a routine basis

only determine the total activity for a specific radionuclide and do not differentiate among different

chemical species that may be present. This requires a methodology that is not part of the normal

analytical processes for these laboratories. 

F. References

Eckerman, K.F., Leggett R.W., Nelson, C.B., Puskin, J.S., and A.C.B Richardson. 1999. Cancer

Risk Coefficients for Environmental Exposure to Radionuclides. Federal Guidance Report

No.13. EPA 402-R-99-001. Oak Ridge National Laboratory, Oak Ridge, Tennessee.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

11

U.S. Environmental Protection Agency (EPA). 1992. Manual of Protective Action Guides and

Protective Actions for Nuclear Incidents. Washington, DC. EPA 400-R-92-001, May. Available

at: www.epa.gov/radiation/rert/pags.htm.

U.S. Environmental Protection Agency (EPA). 1999. Cancer Risk Coefficients for Environmental

Exposure to Radionuclides. Federal Guidance Report No. 13. EPA 402-R-99-001, September.

Available at: www.epa.gov/radiation/assessment/pubs.html.

U.S. Environmental Protection Agency (EPA). 2000. “Radionuclides Notice of Data Availability

Technical Support Document.” Available at: www.epa.gov/safewater/rads/tsd.pdf.

U.S. Environmental Protection Agency (EPA). 2002. Federal Guidance Report 13 CD Supplement:

Cancer Risk Coefficients for Environmental Exposure to Radionuclides. Office of Air and

Radiation, Washington, DC. EPA 402-C-99-001, Rev.1, April 2002. Available at www.epa.gov/

radiation.

U.S. Environmental Protection Agency (EPA). 2008a. Radiological Laboratory Sample Analysis

Guide for Incidents of National Significance–Radionuclides in Water. Revision 0. Office of Air

and Radiation, Washington, DC. EPA 402-R-07-007, January. Available at: www.epa.gov/

narel/recent_info.html.

U.S. Environmental Protection Agency (EPA). 2008b. Standardized Analytical Methods for

Environmental Restoration Following Homeland Security Events, Revision 4.0. Office of

Research and Development, Washington, DC. EPA/600/R-04/126D, September. Available at:

www.epa.gov/ordnhsrc/sam.html. 

U.S. Environmental Protection Agency (EPA). 2009a. Method Validation Guide for Radiological

Laboratories Participating in Incident Response Activities. Revision 0. Office of Air and

Radiation, Washington, DC. EPA 402-R-09-006, June. Available at: www.epa.gov/narel/recent_

info.html.

U.S. Environmental Protection Agency (EPA). 2009b. Radiological Laboratory Sample Screening

Analysis Guide for Incidents of National Significance. Revision 0. Office of Air and Radiation,

Washington, DC. EPA 402-R-09-007, June. Available at: www.epa.gov/narel/recent_info.html.

U.S. Environmental Protection Agency (EPA). (In Preparation). Guide for Radiochemical

Laboratories for the Identification, Preparation, and Implementation of Core Operations for

Radiological Incident Response. Washington, DC.

U.S. Food and Drug Administration (FDA). 1998. “Accidental Radioactive Contamination of

Human Food and Animal Feeds: Recommendations for State and Local Agencies.” 13 August.

Available at: www.fda.gov/cdrh/dmqrp/1071.pdf.

U.S. Department of Health, Education and Welfare (HEW). 1970. Radiological Health Handbook,

p.123. Superintendent of Documents, Government Printing Office. 017-011-00043-0 GPO.

Available for purchase from http://catalog.gpo.gov/.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

12

International Commission on Radiological Protection (ICRP). 1995. ICRP Publication 66: Human

Respiratory Tract Model for Radiological Protection. International Commission on Radiological

Protection, Volume 24, Nos.1–3. Elsevier Science Ltd.

International Commission on Radiological Protection (ICRP). 1996. Publication 72: Age-dependent

Doses to Members of the Public from intake of Radionuclides: Part 5 Compilation of Ingestion

and Inhalation Dose Coefficients. International Commission on Radiological Protection, Volume

26, No.1. Elsevier Science, Ltd.

Multi-Agency Radiological Laboratory Analytical Protocols Manual (MARLAP) . 2004. EPA 402-

B-04-001A, July. Volume I, Chapters 3, 6, Volume II. Available at: www.epa.gov/radiation/

marlap.

Multi-Agency Radiation Survey and Site Investigation Manual, Revision 1 (MARSSIM). 2000.

NUREG-1575 Rev 1, EPA 402-R-97-016 Rev1, DOE/EH-0624 Rev1. August. Available at:

www.epa.gov/radiation/marssim/.

U.S. Nuclear Regulatory Commission (NRC). 1986. “Excessive Skin Exposures Due to

Contamination with Hot Particles,” Information Notice 86-23.

U.S. Nuclear Regulatory Commission (NRC). 1987. “Control of Hot Particles at Nuclear Power

Plants,” Information Notice 87-39.

U.S. Nuclear Regulatory Commission (NRC). 1998. “Protection Against Discrete Radioactive

Particle Exposures,” Rulemaking Plan SECY 98-245. Accession number ML012140137.

Available at: www.nrc.gov/reading-rm/adams.html.

U.S. Nuclear Regulatory Commission (NRC). 1998. Minimum Detectable Concentrations with

Typical Radiation Survey Instruments for Various Contaminants and Field Conditions. NUREG1507. Office of Nuclear Regulatory Research, Washington, DC. Available at: http://techconf.

llnl.gov/radcri/1507.html.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

13

II. RADIONUCLIDES

Table 3 lists some of the radionuclides that are believed to be accessible and possibly could be used

in a radiological dispersal device (RDD), or “dirty bomb,” and the major (noninclusive) dose-related

radionuclides that might be formed from the detonation of an improvised nuclear device (IND).

These radionuclides are addressed in this report. In the case of an IND, numerous short- and longlived radionuclides will be present, requiring proper identification and quantification. Several of the

radionuclides on the list have progeny that will coexist with the parents. Thus, if 228Th were to be

found, 224Ra also would be present (although it is not listed). Several different radionuclides may be

present even if only one RDD is used.

TABLE 3 – Radionuclides of Concern

Alpha Emitters Beta/Gamma Emitters

Radionuclide Half-Life

Emission

Type Radionuclide Half-Life

Emission

Type 241Am 432.6 y α, γ Ac-227† 21.77 y β, γ

252Cf 2.64 y α, γ 242Cm 163 d α Ce-141* 32.51 d β, γ

243Cm 29.1 y α, γ Ce-144‡ 284.9 d β, γ 244Cm 18.10 y α Co-57* 271.7 d ε, γ, x-ray

237Np 2.14×106

 y α, γ, x-ray Co-60* 5.271 y β, γ

210Po * 138.4 d α Cs-134* 2.065 y β, γ

238Pu 87.7 y α Cs-137§ 30.07 y β, γ

239Pu 2.41×104

 y α H-3* 12.32 y β only

240Pu 6.56×103

 y α I-125* 59.40 d ε, γ, x-ray

226Ra† 1.60×103

 y α, γ I-129† 1.57×107 y β, γ, x-ray

228Th 1.912 y α, γ I-131* 8.021 d β, γ

230Th 7.538×104

 y α, γ Ir-192* 73.83 d β, γ

232Th 1.405×1010 y α Mo-99† 65.94 h β, γ

234U 2.455×105

 y α P-32* 14.26 d β only

235U 7.038×108

 y α, γ Pd-103* 16.99 d β, γ

238U 4.468×109

 y α Pu-241 14.29 y α, β

U-Nat — α Ra-228†

 5.75 y β only

Ru-103† 39.26 d β, γ

Ru-106† 373.6 d β only

Se-75* 119.8 d ε, γ

Sr-89* 50.53 d β only

Sr-90† 28.79 y β only

Tc-99* 2.11×105

 y β only

The half-lives of the nuclides are given in years (y), days (d) or hours (h)

*

 No radioactive progeny or progeny not analytically useful.

†

 Radioactive progeny with short half-lives, and the progeny may be used as part of the detection method for

the parent.

‡

 Radioactive progeny not used for quantification, only screening.

§ Radioactive progeny used for quantification only, not screening.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

14

III. DISCUSSION

In order to illustrate the typical decisions and actions to be taken by a laboratory for each scenario,

examples of the three scenarios using theoretical samples and measurement results are provided in

Appendices II, III, and IV. These examples represent only three of many different possible

permutations, however, and should not be construed as limiting. Each example is keyed back to the

steps in its respective diagram and notes.

A. Sampling and Processing at the Laboratory

These scenarios assume that the time period from taking of sample to the actual beginning of the

analysis by the laboratory will be short (< 1–2 days). During the intermediate or recovery phases,

actual sampling duration can be up to one week, so that risk-based ADL concentrations of some

radionuclides can be achieved within a reasonable count time (i.e., lower radionuclide concentrations

will require larger sample volume to achieve detectability). For the three scenarios discussed in this

guide, it is assumed that field personnel have performed some type of radiation screening survey of

the samples prior to sending them to the laboratory. If appropriate, field personnel may determine

which samples are to be submitted first to the laboratory based on these survey results. The

laboratory’s surveys and analyses of the samples are not intended to confirm the field survey results,

but should be used by the laboratory to prioritize samples and determine the potential presence of

short-lived radionuclides.

In some instances, field monitoring results (measured with NaI(Tl), HPGe detectors, scintillation

detectors or proportional counters for field use) will provide information that may help establish the

radionuclides’ identity or energy-specific information regarding the radionuclides involved in the

event. This will help the laboratory to expedite more accurate assessment of the concentration of

these radionuclides.

Only laboratories using validated radioanalytical methods (see Method Validation Guide, EPA

2009a, and MARLAP, Chapter 6) should be used in order to process samples in a timely and

effective manner. These laboratories will have the necessary radioanalytical capability and sampleprocessing capacity to conduct the required gross screening and radionuclide-specific analyses

defined for the scenarios. This guide recommends the following analytical process flow:

 1. General screening based on total radiation emitted from the sample.

 2. Screening based on type of radiation emitted (i.e., alpha, beta, or gamma).

 3. Radionuclide-specific analytical techniques applied after screening indicates the most significant

activities or when the radionuclide(s) have been identified.

This is the sequence used for screening in the flow diagrams for each scenario. Each decision point

in the flow diagram relates to an ADL that is part of the overall analytical process. Many of the flow

diagram boxes have numbers indicating the sequence of the analytical process. The boxes are colorcoded, indicating the most important flow path (red) to the least important (yellow) based on the time

requirements for returning the analytical results. 
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

9

 This is one of several options that potentially could be used. Another option might be to select a portion of the filter

that has a higher loading of the particulates containing the radionuclides. In this instance it may be anticipated that the

final result will be biased high if it is known that the particulates contain the radionuclide(s) of interest.

15

Prior to starting the screening process, it is imperative that the laboratory have some specific

information about the air filters themselves and the sampling parameters:

• Volume of air sampled.

• Beginning and ending times of the sampling period.

• Type of filter medium.

• Percent area of the filter sent to the laboratory (e.g., if the filter was split or “punched” prior to

shipment to the laboratory).

• Contact activity or dose reading of the filter at the end of the sampling period.

This information must be communicated to the laboratory by the field sampling personnel in the

chain-of-custody form. There may be occasions where the entire filter is not sent to the laboratory,

or when the size of the filter sent to the laboratory does not match a calibrated detector geometry:

• When the entire filter is not to be sent to the laboratory, the air particulate filter may need to be

“field split” if there are different laboratories involved with the analytical process, and each one

has different radioanalytical capabilities (e.g., determination of 239Pu/240Pu ratio, or analysis for

a unique radionuclide like 241Am). 

• When the size of the filter does not match a calibrated detector geometry, the laboratory may

have the analytical capability to perform the direct screening measurement on the filter.

However, if the detector geometry that is calibrated does not match the filter geometry, the filter

will need to be “punched” to accommodate this instance. 

In both of these instances, it is imperative that the fraction of the sample used in the screening and

subsequent radionuclide-specific analyses be included in the final radionuclide concentration

calculations. For example, if a 4"-diameter circle is cut from 8×12" filter (e.g., field split), the sample

results must be multiplied by 7.64 to correct for the activity on the whole filter. Another possibility

is that the field sample is a 4"-diameter filter and the laboratory must reduce the size to 2" diameter

(using a punch) to accommodate the laboratory’s instrumentation. In this case, the final value would

be multiplied by 4. Other filter sizes that do not fit a laboratory counting geometry would need to be

corrected as appropriate.

It is likely that particulate matter collected on air filters following an INS will not be uniformly

distributed on that filter. Hot particles and inhomogeneous distributions are likely on the filter.

Therefore, the most representative sub-samples from a filter would be obtained by converting the

entire air particulate filter to a homogeneous form, such as a digestate, prior to sub-sampling. In

some cases, a portion of the filter should be retained for future use, or a filter may need to be

punched to create a reproducible geometry for rapid screening of the sample. A universally accepted

methodology for splitting or sub-dividing an air particulate filter does not exist. In cases where the

filter must be split prior to digestion, it is important that the laboratory has (and adheres to) written

guidance on how the sub-sampling is performed. For example, the guidance may stat to use a 10×

magnification and visually identify an area that visually appears uniform in particle deposition.9

 Sub-
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

16

sampling will create bias in the analytical results, and subsequent results should be used with this

understanding. Once a filter has been sub-divided for screening (by cutting or punching out a

section), the remaining filter should be retained so that all sample constituents are included in the

final analysis.

The screening techniques outlined in the first steps of the flowcharts assume that the laboratory

maintains the necessary instrumentation and can perform the initial gross sample screening (at or

immediately subsequent to sample receipt) functions identified below:

• Micro-R meters for evaluating radiation exposures and doses on low-activity samples.

• Dose-rate meters capable of detecting gamma-beta exposures and doses.

• Hand-held gross alpha frisker for assessing the alpha count rate on sample contact.

• Probes that can be used to determine whether samples exceed the maximum dose rate that can

be handled or analyzed at the laboratory.

It is important to note that none of these screening instruments are suitable for all types of emissions.

It may take measurements from two or three different types of screening instruments to assess the

total potential activity present and only the combination of the results should be used to prioritize

the sample processing at the laboratory. Further discussion of some of the assessment of these

measurements may be found in Radiological Laboratory Sample Analysis Guide for Incidents of

National Significance – Gross Sample Screening Analysis (in preparation).

The laboratory also should have the instrumentation to perform gross radioactivity measurements

either before or after chemical separation (e.g., gas proportional or liquid scintillation counters) and

radionuclide-specific analyses (e.g., high-purity germanium detectors). Some of the radionuclides

listed in Table 3 (e.g., 103Pd) can be detected only with a specific type of gamma-ray detector because

of their low gamma-ray emission energy (60 keV is the usual lower limit of calibration for many

high-purity germanium [HPGe] detectors).

Each numbered box has an associated note that provides additional detail for that particular part of

the process. Clarification is also provided in these notes as to when parallel paths of analysis should

be followed to help expedite the processing of samples.

Appendix V (Table 9) contains generic assumptions that can help laboratory personnel in assessing

count times for screening samples for gross radioactivity. The information in the table may assist in

determining the approximate time it will take to achieve the required method uncertainty for the

decision points in the flow diagram for two different screening methodologies. Laboratories should

prepare their own spreadsheets, in advance of an event, using their preferred methodology.

Laboratories also should determine (in advance) whether their individual analytical protocols will

need to be revised to accommodate this process. The flow sheets used in this document that describe

the screening process use gas proportional counting for various air volumes collected and

instrument-count times. It is important to point out that the volume of air collected will most likely

be highly variable. Thus it is incumbent on the laboratory personnel to know that the count times on

each instrument are based on the total number of picocuries that may have been deposited.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

17

The number of samples that will be analyzed and their level of radioactivity may be significantly

greater than samples routinely analyzed. Laboratories must also consider the following:

• Establishing separate procedures for sample handling and storage.

• Identifying protocols for personal protective equipment that are commensurate with the radiological hazard.

• Additional protocols for personnel and sample radiation monitoring.

• Increasing the frequency of detector background analyses.

• Obtaining tracer solutions of higher activity.

• Increasing the frequency of QC checks.

• Adjusting the QC-check activity level to more closely align with the activity of the anticipated

samples.

• Increasing the frequency of contamination assessments (i.e., smears/swipes) on working surfaces

in the laboratory.

• Separating the storage location for high activity samples from personnel and instrumentation

(possibly with additional shielding).

• Monitoring dead time for individual samples.

• Revise automated count times based on achieving the required method uncertainties.

If laboratory protocols for routine situations cannot ensure that the MQOs for incident-specific

samples are achievable with the laboratory’s SOPs, then a separate set of SOPs for incident response

sample conditions will need to be developed and validated. Further information on developing

incident-response laboratory operations may be found in EPA’s Guide for Radiochemical Laboratories for the Identification, Preparation, and Implementation of Core Operations for Radiological

Incident Response (in preparation). 

B. Discrete Radioactive Particles

An important consideration for air particulate samples taken following a radiological or nuclear

event is the likelihood of encountering “hot” particles. The radioactive components used to make

an RDD, for example, likely would be from commercially available, solid materials. The conventional explosive used to disperse the radioactive material would intermix radioactive fragments with

other debris, resulting in a distribution of particle sizes, all mixed together and trapped on an air

particulate filter according to the filter’s characteristics. Hot particles, termed “discrete radioactive

particles” (DRPs), will be small, on the order of 1 mm or less. Discrete radioactive particles are

typically not evenly distributed on an air particulate filter, and their radiation emissions are not

uniform in all directions (anisotropic).

The radioactive sources/materials that may be potentially used in an RDD event emit alpha, beta, or

gamma radiation (see Table 3), and although highly radioactive, they may not be identified with field

equipment using conventional scanning techniques on field surfaces such as concrete or soil due to

their small size. This will present problems to the field sampling teams from certain perspectives:

• A hand-held field scanner may provide low activity or dose readings if it is not performed slowly

enough. This can lead to exposure to individuals because they think the air particulate sample

is not highly radioactive based on the area deposition surveys.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

18

• It may cause them to classify an area under one category of contamination (when using only

scanning techniques on surfaces) when in fact it may have higher exposure concerns due to the

DRPs.

The laboratory will have similar issues to those of the field sampling team. When processing samples

that contain DRPs, the material may be relatively inert and not easily dissolved (192Ir is an example

of a material that would not be dissolved easily by traditional laboratory digestion techniques).

Laboratory personnel should be aware that significant information may be derived from solution

residues that contain radioactive materials (e.g., DRPs). These residues should undergo either fusion

or digestion with hydrofluoric acid (HF) to ensure that they are solubilized. HF may be better for

samples that only have alpha-emitting radionuclides because its use minimizes the addition of other

solid matter to the final counting form, which in turn minimizes sample self-absorption. Alternately,

the entire particulate filter may need to be analyzed directly, as a solid matrix (this may require

special processes). Great care should be used when deciding to sub-sample an air particulate filter

that may have DRPs. This type of material, by its nature, will result in non-uniform deposition on

the filter. Either the whole filter should be used, or an alternative means for identifying a

representative portion of the filter should be determined. In addition, because these recommendations

identify analytical priorities for samples based on their screening values, samples with DRPs could

get misclassified and put on a lower-priority track. 

DRPs usually will have a high electrostatic charge due to their high specific activity. This

phenomenon has been observed at nuclear power plants that have had major fuel defects. The small

fuel fragments can be transported to various locations throughout the reactor coolant system. When

the system is opened for maintenance, and liquid, air, or swipe samples are obtained and the samples

allowed to dry out, the DRPs will “jump.” This jumping phenomenon may occur with any highly

radioactive, micron-sized particles. 

Finally, laboratory personnel also must be wary of dosimetry readings involving DRPs if they are

not experienced with personal frisking techniques. The personal dosimeter reading either will yield

a very high reading (if the DRPs are near or in contact with dosimeter) or a background reading (if

the DRPs are distant from the frisker or probe). The technique used in frisking should take into

account these concepts and should allow accurate assessment (assignment) of dose based on the

particle and its location. 

C. Sampling for Iodine and Tritium

Air particulate filters are not acceptable methods for collecting samples containing radioiodines or

tritium, because of the volatility of these elements under environmental conditions. Therefore, during

the initial phase of an event, additional matrices described below may be presented to the laboratory

for analysis of these two radionuclides. If neither radioiodine nor tritium is present, these additional

sample matrices will not be necessary. Tritium is a radioactive form of hydrogen. If tritium is used

in an RDD, it will become exclusively associated with water (chemical formula, 1

H-O-3H, tritiated

water) regardless of its initial chemical form. The sampling techniques used for normal water in a

vapor phase also can be used for tritiated water. The following list includes only some of the media

that the laboratory may receive if tritium-aerosol sampling is performed:
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

19

• Drierite®

• Molecular sieve

• Water (from an air bubbler collection method)

• Sodium carbonate

• Ethylene glycol solution

• Silica gel

These matrices would be preceded by the particulate air filter in the sample flow path so that

particulate matter is trapped only by the particulate filter. The above media cannot be prioritized for

analysis by the laboratory following receipt because neither field nor laboratory survey instruments

are effective at detecting tritium in these matrices. Thus, all sample media for tritium analysis would

need to follow a prioritization designated by the IC. Samples should be appropriately packaged,

shipped, and handled to avoid inadvertent dilution with water or loss during processing. The most

effective methods of tritium separation from all other radionuclides are ion exchange (to remove all

other radionuclides), distillation, or freeze-drying (although other techniques can be successfully

employed).

Iodine, as compounds of inorganic iodide, is susceptible to oxidation to molecular iodine, I2. In this

case, iodine may not be captured effectively on a particulate filter. Iodine may also exist in the

atmosphere as an organically bound compound and would likewise not be captured effectively on

a particulate filter. 

In order to accommodate the potentially different chemical forms of iodine that may be present,

different collection media may be required. Some techniques that have been used for field sampling

of volatile radioisotopes of iodine include:

• Charcoal or activated carbon cartridges (usually containing triethylenediamine, TEDA)

• Molecular sieve (containing silver halide, also known as silver zeolite cartridges)

• Charcoal or activated carbon cartridge (containing silver halide)

• Water containing alkaline thiosulfate solution (from an air bubbler collection method)

The three radioisotopes of concern, 125/129/131I, all can be sampled effectively using these media as

long as the chemical form of the iodine is susceptible to air oxidation. If the iodine compound is

chemically stable with respect to oxidation, it may be possible to collect the material on the filter.

Organically bound iodine will be effectively removed from an aerosol using charcoal cartridges

containing TEDA. Regardless of the media, potential radionuclides of concern that have short halflives, such as 131 I (t1⁄2 . 8 d) and 125I (t1⁄2 . 60 d), should be analyzed promptly upon receipt. For

example, 131 I is easily detected, without any sample preparation, using gamma-ray spectrometry. The

detection of 125I can be done using a low-energy gamma-ray detector. Based on environmental

conditions, the sampling cartridges may be face- or fully loaded (see page 25).

Once the radionuclides have been identified, special measures will need to be taken to detect the

particular radionuclides resulting from this event. These will involve modification of scanning

techniques (both in the laboratory and in the field measurements), more frequent contaminationcontrol measures, and attention to the total particulate mass and moisture content of the samples. It
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

20

will also require that laboratory personnel be vigilant in the observation of residues in the sample

digestion processes.

D. Crosswalk of Data Values

The values corresponding to different terms referred to in this document are located in the tables

listed below:

TABLE 4 – Crosswalk of PAG, AAL, ADL, and uMR Values

Data or Value AAL ADL uMR

2-rem/500-mrem

(Screening)Tables 7A and 7B

Tables 7A and 7B Tables 7A and 7B Tables 7A and 7B

2-rem/500-mrem

(Radionuclide-specific)Tables

7C and 7D

Tables 7C and 7D Tables 7C and 7D Tables 7C and 7D

10–4 risk— Tables 8A and 8B Tables 8A and 8B Tables 8A and 8B

10–6 risk— Tables 8A and 8B Table 8A and 8B Table 8A and 8B

DQO and MQO

Derivations—

— Tables 11A, 11B,

12A, 12B and 13

Tables 11A, 11B, 12A,

12B and 13

Estimated counting

timeTables 9 and 14

Tables 9 and 14
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

21

< 500-mrem

ADL

2. Rapid gross "/$ on filter 

by GPC. Perform gamma

spectrometry on filter. 

Yes

3a.

Compare α, β, γ

results to ADLs in

Tables 7A and 7B

(see notes)

9. α emitters by

chemical separation

8. β emitters by

chemical separation

13. Long gamma

spectrometry and gross 

α/β count time

14.

Any α, β, or γ

Result >

Table 7A or 7B 

500-mrem

ADL?

No

Yes

6.

Gross 

β/γ >2.5

?

No

7. Perform 

total Sr analysis

17. Archive final 

sample forms; 

segregate from low 

activity archived 

samples

Highest priority

(> 2 rem)

Second priority

(> 500 mrem)

Lowest priority

(<500 mrem)

End result

Key

See accompanying tables 

for alpha and beta/gamma

concentrations, and 

numbered notes

Highest priority

(> 2 rem)

Second priority

(> 500 mrem)

Lowest priority

(<500 mrem)

End result

Key

See accompanying tables 

for alpha and beta/gamma

concentrations, and 

numbered notes

Air Filter Analysis — High Flow Sampler

Background Information

• Unknown source

• Priority to those samples with highest activities

• Field sample volume collected 3–100 m3

• Separate samples received from field for 3H and 

iodine

12. Report results to IC

15. Follow Scenario 

2

1a.

Value for

gross α > Table 7A, Or 

gross β/γ > Table 7B

ADLs for 2-rem?

Yes

1b. Perform 3H 

analysis on aerosol 

sample

No

>500 mrem and

<2 rem ADL

4. Dissolve filter 5. Reanalyze gross α/β

4. Dissolve 

filter

5. Reanalyze 

gross α/β

>2-rem ADL:

Report to IC

16. Reanalyze 

if possible; note discrepancy

10. Gamma

Spectrometry

1.Rapid lab scan 

for β/γ and α

No

Yes

1c. Perform iodine 

cartridge gamma

spectrometry for 131I, 125I, 129I

11. 

Any individual 

result > Table 7C

Or Table 7D ADL ?

OR

Sum of fractions

>1.0?

3b. 3H >Table 7B 

OR any of

[ 131I, 125I, 129I] >

Table 7B 2-rem

ADL

?

Report Results

To IC

Yes

No

Go to Step 13

Figure 2 – Air Scenario 1 Analytical Flow

IV. SCENARIO 1 (Identifying Air Samples with Highest Activities)
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

10 The sampling team needs to provide the laboratory with an unused particulate air filter, so that a blank weight can be

determined. This would be used to assess the total particulate loading on the filter so that self-attenuation factors can be

estimated.

22

Notes to Scenario 1: High-Flow Air Sampling

Purpose: Priority to those samples with highest activities

Important Sampling Notes: Sample time will be short; sample volume will be small

In this scenario, prioritization of sample analyses in the laboratory is based on the observed

sample activity at the various steps in the analytical process. Samples with activity that exceed

the 2-rem ADLs will get the highest priority. Samples with activity less than the 2-rem ADLs but

more than the 500-mrem ADLs will get an intermediate priority, and samples with activity below

the 500-mrem ADLs will get the lowest priority. Samples may arrive over several days; those

with the highest priority (red flow path on this diagram) are always to be analyzed first. Only

after an analytical step or procedure has been completed for the highest-priority samples should

lower-priority samples be addressed. Lower-priority samples (those following the green and

yellow flow paths on this chart) may need to be stored for several days until analysis of the

highest-priority samples has been completed. Some of the information in Step 1 is the responsibility of the field sampling team but is needed by the laboratory so that the final analytical result

can be calculated.

High-flow sampling rates are on the order of 30–50 ft3

/min (0.85–1.4 m3/min) with sample

volumes typically greater than 2×103

 ft3 (55 m3), but between 100 and 3.5x103 ft3 (between 3 and

100 m3

) for a one-hour collection time. A one-hour nominal volume of ~2.4 x103 ft3 (~68 m3)

taken through a 4" air filter is assumed for this scenario. 

The laboratory will need to be notified by the sampling team if sampling was conducted in a

highly dusty environment (much greater than 100 μg/m3

). If this is the case, the solids loading

(mg/cm2

) on the filter will need to be assessed10 so that self-attenuation factors can be

determined, especially for alpha analysis. The charcoal cartridge will be downstream of the

particulate filter. The flow-monitoring device should be placed downstream of the filter housing

but upstream of the pump, ensuring that the net flow through the media can be calculated

accurately.

Many of the flow diagram shapes are color-coded to reflect the highest-priority analytical flow

path (red), intermediate (next important) flow path (green), or the lowest-priority flow path

(yellow) based on the time needed to return the required analytical results to the IC. The

accompanying numbered notes are color-coded in the same fashion, as are the examples in

Appendix II. It is highly advisable to study the flow paths in color, as a black-and-white printing

may be confusing or ambiguous. 

Note also that as the sample screening and analysis progresses in the laboratory, there are

sequential decision steps to guide the sample to the correct priority path. For example, Diamond

14 in the preceding figure checks for gross alpha/beta on the filter using GPC or gamma analysis,

with longer count times to ensure that the sample activity is less than the 500-mrem AAL.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

23

1. The laboratory instruments used might include a survey meter (with alpha and beta channels)

or a Geiger-Muller (GM) counter with appropriately calibrated beta and gamma detector

probes, or a micro-roentgen meter (gamma only). This step will be conducted in the

laboratory initially with the particulate filter in its container. The first measurement will be

for gross β/γ to assess overall exposure and potential contamination. Once it has been

determined if any other precautions are necessary for direct measurement (e.g., fume hood,

protective breathing equipment, etc.), then the filter is removed from its container so that the

alpha measurement can be assessed more accurately. Unless the identity of the radionuclide

contaminant is known, the hand-held survey instrument should be calibrated using a standard

source (e.g., 241Am for α, 90Sr for β, or 137Cs for γ) that will replicate the particulate filter

geometry.

Activity measurements of one type of radiation that are high due to the level of

contamination present may cause a measurable response with a different screening detector

although significant quantities of that radiation may not be present (e.g., crosstalk). For

example, a sample that is highly contaminated with 90Sr may appear to contain alpha activity

if beta emissions are misclassified as alpha emissions as a result of beta-to-alpha crosstalk.

A discussion of this type of instrument response is found in Radiological Laboratory Sample

Analysis Guide for Incidents of National Significance – Gross Sample Screening Analysis

(in preparation).

Important sampling information will be the start and stop times of the air sampler, total

volume sampled, and the time that survey-meter measurements of the filters were made.

Field staff may prioritize the samples being sent to laboratory based on their survey-meter

scans of the air filter samples. Field survey meters using gas proportional (GP) or GM

detectors should be able to detect the radioactivity collected in 68 m3

 of air having a 2-rem

or 500-mrem AAL for most targeted β-emitting radionuclides (NRC, 1998). 

During this sample processing phase, special precautions should be taken to avoid sample

cross-contamination as well as laboratory contamination from samples that may have loosely

held radioactive particulate matter.

Special precautions should be taken when performing initial scans to account for the

potential presence of DRPs, especially if the filter is large enough so that more than a single

reading is required. If “hot” particles are found, it is very important to communicate this

information immediately to field personnel. If DRPs are present, additional sample handling

controls may be necessary, such as:

• Establishing a “hot-particle” sample handling and storage area with step-off pads;

• Extra personal protective equipment for normally exposed body surfaces; and 

• Single-sample handling until the sample digestion has started (to prevent crosscontamination).

The MQOs at the 2-rem and 500-mrem AALs for required method uncertainty can be found in

Tables 7A and 7B.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

24

Laboratory personnel should be aware that when using the nominal volume for the sample

(68 m3

), the 2-rem AAL concentrations correspond to a total activity of about 48 pCi for

alpha and 29,000 pCi for beta. Laboratories should have screening equipment that is capable

of detecting the range of activities at the 2-rem ADL total activity (for a 68 m3 sample) of 24

pCi for alpha emitters and 14,000 pCi for beta emitters.

1a. If the gross screening value is less than the 2-rem ADL values listed in this diamond, the

sample reverts to a lower priority (green). The ADL values for alpha and beta are 0.35 and

210 pCi/m3, respectively. If sample screening measurements are less than these values when

the uMR is achieved, the sample is put on the lower-priority flow path. Otherwise, the sample

stays on the high-priority pathway.

1b. Tritium assessment generally is not performed with screening equipment because of the low

energy of its emitted beta particle and the significant effects of non-radiological interferences

with its analysis. Sample volumes and times will usually be different for samples obtained

for tritium analysis (the volumes for tritium sampling routinely are lower). The media used

for trapping tritium are described in Section III. The laboratory must have a procedure in

place to handle the media used for trapping tritium, as each has separate retention factors and

potential diluents (water) that can alter the final tritium concentration. Screening

measurements on the aerosol’s water fraction are made without removing interfering

radionuclides. This means that at this step in the process, tritium results are of screening

quality only. Inspection of liquid scintillation spectra may enable elimination of some

radionuclide interferences based on beta particle energy distributions.

The gross alpha/beta air filter and the gamma spectrometry on the iodine cartridge analyses

should be performed in parallel. Information from this gross screening may provide insight

into potential for interference with tritium analysis.

A simple distillation, collecting approximately 5 mL of liquid, may provide the most

effective removal of all interfering radionuclides from the collection media used for water.

Sample count times using liquid scintillation will be short in order to demonstrate that the

sample concentration exceeds the 2-rem ADL value of 1.3×105

 pCi/m3. The uMR value is

7.9×104

 pCi/m3.

The laboratory should not make decisions regarding the priority for the corresponding

particulate filter or iodine cartridge based on the tritium analysis until Step 3b is completed.

 Similar consideration for a standard source calibration (137 1c. Cs for γ) and geometry should be

given to the cartridge used for iodine/noble gas sampling.

An iodine cartridge may be used in combination with a particle filter (the filter preceding the

radioiodine collection cartridge in the flow path) during the sample collection process. Thus,

the sample time and volume should be the same for these two separate collection media. At

the laboratory, the alpha-beta gross analysis of the particulate filter by gas proportional

counting (GPC) should be corrected for self attenuation if the mass of material collected on

the filter can be or has been determined. 
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

11 This term describes the concentration of the radionuclides of interest in a thin slice of the entire cartridge width that

faces the inlet air flow. At low concentrations, this will usually be the case, but loading can be affected by humidity,

temperature, and presence of other gases that may be adsorbed by the cartridge. One technique that may avoid the issue

of face versus fully loaded is to “side count” the cartridge. The gamma spectrometry detector must be calibrated for this

special geometry.

12 For an event that involves a nuclear power plant release, there may be a significant amount of radioiodines on the

particulate filter. This depends on several factors including the chemical form of aerosols during the release.

25

Gamma spectrometry of the cartridge is specifically for 131I (364.5 keV is the principal

gamma ray). Although the 129I or 125I may be present, their activities would need to be verified

in the longer gamma count intervals using a low-energy gamma-ray detector. It is likely that

an iodine cartridge will be “face-loaded.”11 However, the laboratory must be able to confirm

this assumption. Laboratory counting techniques must be able to account for differences in

face or fully loaded cartridges. Cartridge orientation when counting, as well as proper

calibration for that geometry, must be ensured. Although possible, it is not likely to detect

131, 129, 125 I on the particulate filter.12 If iodine is present on the filter, the most likely form

would be an iodide salt. Additionally, because the energy of the 129I and 125I gamma rays are

~35 keV, the laboratory should ensure that a valid calibration curve exists at the energies of

these radionuclides and that they consider corrections for self attenuation of the gammas by

the sample matrix. If radioisotopes of iodine are present on both particulate filter and

cartridge the sum of the two contributions (for the same radioisotope of iodine) must be

assessed versus the ADL for that radioisotope of iodine.

It is also possible that noble gasses, such as krypton and xenon (if present from a nuclear

detonation or power plant accident) or radon (and its decay products), would be captured on

the iodine cartridge. Thus, the gamma-ray energies from these radionuclides and their decay

products should be in the gamma-ray library. Count times should be 5 to 10 minutes.

Gamma-ray lines with net peak area uncertainties <50% (at the 1-sigma level) should be

positively identified and quantified to aid in direction of additional analyses. Significant

quantities of radon on the radioiodine collection cartridge should alert the laboratory to the

presence of unsupported progeny on the filter or cartridge that emit alpha, beta, or gamma

radiation. The gross alpha/beta air filter and the gamma spectrometry on the iodine cartridge

analyses should be performed in parallel. 

The laboratory should not make decisions regarding the priority for the corresponding

particulate filter or tritium sample based on the iodine analysis.

The 2-rem uMR values for screening analysis for iodines are based upon the sum of iodine

activity from vapor trapped on a cartridge or any particulate caught on the filter upstream of

the iodine cartridge. The specific values for 125I, 129I, and 131I are presented in Table 7B.

Proceed with Step 3b.

2. Direct gross alpha/beta analysis of the particulate filters may be performed with a portable

or laboratory, low-background GPC unit. When making these measurements, consider the

levels of activity that were measured for each of the samples in Step 1 to avoid contaminating

low-level background detectors with samples that have very high activity. 
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

26

NOTE: Laboratory personnel also must know if the shipped sample is only part of a larger sample,

so that appropriate correction factors can be applied before reporting final results. For example,

if a 4"-diameter circle is cut from 8×12", or if a 4"-diameter filter is received and the laboratory

needs to reduce the size to 2" diameter, then the laboratory must calculate the appropriate

correction factor for the fraction of filter analyzed (see discussion of filter sizes on page 15).

Special contamination-control procedures should be implemented when transferring filters

that may contain high activity in order to avoid contaminating areas that normally have low

background and contamination. Examples of such procedures include a separate enclosed

area for transferring a sample from one container to another, double containers, and thin

encapsulating film such as collodion on the filter surface.

Lab assessment of the total activity decay during transport can provide information regarding

the half-life of the principal radionuclides. The activity ratio of field to lab analysis for gross

β/γ activity may be used to estimate the composite half-life of the radionuclides contained

in the sample to help resolve discrepancies between field versus laboratory gross-activity

measurements. For example, if a sample is received 24 hours post-incident and the laboratory

gross β activity is ~20% of the field activity measurement, thoron (220Rn) decay products of

212Pb/212Bi may be involved. 

If the laboratory finds that its receipt survey is significantly different from the field survey

of the sample, it may be important to know which reference radionuclide was used to

calibrate the field survey detector. 

The sample chain-of-custody form must specify if the field measurements were made on the

entire filter, or just the portion shipped, so that lab measurement can be compared with the

field measurements. This will assist in gaining insight into the quantity of short-lived

radionuclides that may be present (this will help in the gross activity assessment when

compared to the sum of individual radionuclides in Step 11). The field sample team should

have provided specific information regarding the composition of the filter medium (including

a blank sample) so that appropriate steps can be taken during the filter-digestion process.

Gamma spectrometry is performed on the entire filter sample initially to assess which gamma

emitters may be present. Although possible, it is not likely to detect 131, 129, 125 I on the

particulate filter. If iodine is present on the filter, the likely forms would be an iodide salt or

iodine trapped with particulate matter. Additionally, because the energy of the 129I and 125I

gamma rays are ~35 keV, the laboratory should ensure that a valid calibration curve exists

at the energies of these radionuclides and that it considers corrections for self attenuation of

the gammas by the sample matrix. Count times will vary depending upon the sample size and

efficiency of the detector. However, count time should be at least 15 minutes (this helps to

ensure software routines have sufficient data to properly perform peak fitting algorithms).

The uMR values at the 2-rem and 500-mrem ADL for gross alpha are 0.21 and 0.052 pCi/m3

and that for the gross beta 130 and 33 pCi/m3, respectively (Tables 7A and 7B).

3a. Initial assessment of the activity is made based on comparison with the 2-rem ADL values:
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

27

NOTE: If either the gross alpha or beta ADL (at 2-rem or 500-mrem) is exceeded, a second analysis

should be performed for gross alpha and beta after dissolution, for the ADL (alpha or beta) that

was exceeded (see Step 5a). See a more detailed explanation of this under “Additional Points” on

page 31.

• The gross alpha-beta analysis of the filter (gross α > 0.35 and gross β > 210 pCi/m3), and

• The short-count gamma spectrometry results (Step 2, γ> 2-rem ADL values; see Table

7B). 

If any 2-rem ADL is exceeded, notify the IC immediately and indicate that these results are

based on screening methods and radionuclide-specific analyses have not yet been performed.

Based on gamma spectrometry results, determine if the radionuclide used for gross beta

calibrations should be adjusted. For example, if gross beta was determined using a 90Sr/90Y

calibration source and the only radionuclide is 60Co, an adjustment in the attenuation factor

may be necessary (this could be made based on actual sample measurements or calibration

with the radionuclide source if available). 

Determine if any individual gamma emitter exceeds its 2-rem ADL. Gamma-ray lines with

net peak area uncertainties (or as identified by the instrument manufacturer) below 50%

should be identified and quantified to aid in direction of additional analyses.

Review the original gross alpha/beta results based on the self-attenuation assessment above.

Determine if the gross alpha/beta ADL assessments have changed from the original

assessment made in Step 2. 

3b. The following analyses will have been completed:

• Tritium-specific analysis from a separate sample (Step 1b), and

• Iodine-specific analysis from a cartridge (Step 1c).

The IC should be notified immediately if any of the following 2-rem ADL values identified

in Tables 7A or 7B are exceeded :

• 3

 H

• 125I

• 129I

• 131I

If not, a longer gamma count for the iodines and a longer liquid scintillation analysis for

tritium should be performed for Step 13 (to be conducted later). It is important to note that

this analysis flow path is only for tritium and iodines. The particulate filter associated with

the tritium and iodine analysis may remain on the high-priority flow path based on its

screening analysis completed in Steps 1 or 2. If radioiodines are detected on the cartridge,

a gamma count of the particulate filter should be performed to identify any additional

radioiodine contribution prior to assessing what AAL may have been exceeded.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

13 This is particularly important if the presence of DRPs is known or suspected.

28

4. Once the α, β, and γ analyses from Step 3 are complete, the entire filter sample should be

dissolved so that separate aliquants of the final digestate may be analyzed simultaneously for

specific α- and β-emitting radionuclides. A fusion technique that uses a low-temperature

flux, or an acid digestion that ensures a single, homogeneous phase should be applied.13 If

glass-fiber filters have been used, some form of fluoride treatment should be used to

eliminate silica precipitation later in the analytical process (for example, sodium fluoride

[NaF] fusion or hydrofluoric acid [HF] removal of silica are commonly used techniques). HF

may be better for samples that only have alpha-emitting radionuclides because its use

minimizes the addition of other solid matter to the final counting form, which in turn

minimizes sample self-absorption. Note that any method used to dissolve the filter may

reduce or eliminate the activity of any volatile or semi-volatile radionuclides present on the

filter. Therefore, analyses for tritium and radioisotopes of iodine, phosphorus, and sulfur will

need to be performed in a manner that prevents their loss during sample preparation and

analysis. 

Sufficient final volume of the digested sample should be saved for subsequent removal of

aliquants for specific alpha- and beta-emitting radionuclides. This should include an aliquant

that may need to be recounted by gamma spectrometry for a longer period of time (2–3

hours). Ensure that the calculation of the final activity of the sample corrects for that fraction

of the digested solution or filter actually used in the analysis.

5. If either the gross alpha or beta ADL determined in Step 3 was exceeded (2-rem or 500-

mrem values), a re-analysis should be performed for the corresponding ADL (α or β) that was

exceeded. Based on the screening analyses, it may be best to gamma-count the entire

digestate for a longer period of time (such that the uMR, see Table 7B, is achieved, e.g., 4–6

hours) before subdividing the digested sample for other individual analyses. Any gammaemitting radionuclide with a measured activity greater than its calculated critical level should

be included in the total gamma activity sum.

6. Calculate the total gamma activity per cubic meter in the samples as the sum of all gammaemitting radionuclides (Step 2) with measured activity greater than the critical level. If the

ratio of gross beta (from Step 5) and total gamma indicate a gross beta/gamma ratio > 2.5,

immediately start total strontium (89+90Sr) analysis. The alpha-spectrometric and beta-only

analyses always should be performed as soon as possible after the start of the Sr analysis,

regardless of the strontium results. If gross β/γ ratio is < 2.5, perform Steps 8, 9 and 10 in

parallel. If β/γ ratio is > 2.5, immediately start total strontium analysis (89+90Sr). 

7 The strontium analysis should provide a rapid assessment of total radioactive strontium

(

89+90Sr) in the sample. If total radiostrontium analysis indicates the presence of radiostrontium at greater than 0.71×AAL for 90Sr (this represents the corresponding ADL for 2-rem or

500-mrem), the sample should be recounted 24 hours later to assess the distribution of the

two radiostrontium isotopes in the sample. Some beta measurement techniques may allow

for assessment of 89Sr and 90Sr, separately, based on the beta particle energy distribution.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

29

NOTES: 

• Steps 8, 9, and 10 should be performed in parallel. Although all the radionuclides listed in

Table 3 are possible contaminants, perform those analyses that are most probable based on

previous sample results and direction by the IC.

• Samples from the same event and area may be queued more accurately using the information

already obtained on the first batch of samples. For example, if 241Am is one of the known

contaminants, that analysis would be started first in Step 9.

NOTE: The sum of the fractions (individual beta/gamma radionuclide concentrations divided by

their respective 500-mrem AAL value—see Table 7B and “sum of the fractions” in the glossary)

of all radionuclide concentrations above their individual critical level is to be calculated. This

includes all naturally occurring radionuclides above their respective critical level even if the

naturals are not part of the event. If the summed value exceeds unity, then the 500-mrem AAL has

been exceeded, even though an individual radionuclide activity value does not exceed its respective

AAL. If all comparisons are satisfactory and data quality requirements have been met, report results

to the IC. If there are outstanding data quality requirements or activity measurement issues, go to

Step 16.

8. Using input from the gross beta and gamma spectrometry measurements, begin pure betaspecific analyses (plus 227Ac) based on the radionuclides identified in Table 3. This includes

analysis for 90Sr if not already started. The corresponding ADL and uMR values are found in

Table 7D.

9. Using input from the gross alpha and gamma spectrometry measurements, begin alphaspecific analyses for the radionuclides identified in Table 3.The corresponding ADL and uMR

values are found in Table 7C.

10. Conduct gamma spectrometry of sufficient time to meet the corresponding ADL and uMR

values that are found in Table 7D. All gamma-ray-emitting radionuclides that result in a

radionuclide activity above the critical level should be included with their associated

uncertainty on the final report to the IC. This would make the IC aware of other radionuclides

that may be present at lower concentration that may not be of dose consequence, but that may

affect remediation efforts. Any gamma-emitting radionuclide with a measured activity

greater than its calculated critical level should be included in the total gamma activity sum

and in the sum of the fractions (Step11).

11. As testing results become available, verify that data quality requirements have been met for

each of the analyses and take action promptly to address any deficiencies identified. This

includes any quality control sample requirement results (e.g., liquid scintillation counters

[LSCs]) imposed on the laboratory by the available project plan documents or contract. Once

a final result is available, compare the individual radionuclide concentrations to the

individual ADL values listed in Tables 7C and 7D. When the high- and intermediate-priority

radionuclide-specific analyses are completed, verify that no major nuclide has been missed

and that data quality requirements have been met. This can be done by verifying that the sum

of the individual nuclide concentrations is approximately equivalent to the gross activity

concentration (a rule of thumb is within a range of about half to twice the gross value).

Activity concentrations due to decay products should be included in the verification.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

30

12. Report all final reviewed results to the IC and provide electronic data deliverable (EDD).

Clearly identify any sample activity or concentration totals that do not compare favorably

with the original gross activity or concentration measurements. 

13. On this lower-priority flow path, the gross screen of the samples has indicated lower activity.

The sample count time should be long enough so that the required method uncertainties for

10–4 and 10–6 risk factors listed in Tables 8A and 8B can be achieved. This will assist in

identifying the presence of lower activity radionuclides that may be present.

This count is performed to assess if the sample result is greater than the 500-mrem ADL as

indicated in Tables 7A and 7B for:

• Gross alpha

• Gross beta

• Any beta-gamma emitter

If the sample result is less than the 500-mrem ADL, the sample is put on the low-priority

track (yellow, Step 14). If the sample result is greater than the 500-mrem ADL, the sample

goes to Step 4 for an intermediate priority. 

The radioiodine collection matrix may be re-counted now for sufficient time to meet the

required measurement uncertainties identified in Table 8B, and should be counted on a

detector that is calibrated for gamma rays as low as 30 keV. Do not allow significant delay

in counting the iodine cartridge due to short half-life of 131I.

A longer gross α/β count of the filter is appropriate using GPC to assess if the sample activity

is between ADLs corresponding to the 500-mrem and 2-rem AAL values (use Tables 7A and

7B). The length of count will depend on the fraction of original sample which is being

analyzed.

If tritium was not initially identified above the 500-mrem AAL (Step 3b), a longer liquid

scintillation count at this time may be warranted to assess its presence at greater than ambient

levels. 

14. If the gross alpha or gross beta results, or the longer gamma count results do not exceed the

500-mrem ADL for any radionuclide concentrations listed in Tables 7A and 7B, then go to

Step 15 (sample has not yet been dissolved). If the sample is greater than the 500-mrem

ADL, return sample processing to the analysis flow path, Steps 5–12, with a secondary

(green) priority. 

15. Samples that have activities that are low enough to fall into this category should be preserved

(if needed) for analysis in the future (as directed by project management) using the scheme

outlined for Scenario 2 (specifically at Steps 13a or 13b).

16. Recount samples or re-analyze aliquants of the remaining solution after digestion to

determine if an interfering radionuclide or non-radioactive contaminant interfered with the
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

31

analysis. Determine if gross alpha/beta efficiency factors used for the gross activity

measurements (Step 5) should be updated to radionuclides now known to be present in the

sample. If no cause of the discrepancy can be determined, make note of the discrepancy in

the report to the IC. 

17. Archive final sample test sources that were counted and digested in Step 4. These samples

should be segregated from the lower activity samples, such as those that may have been

archived in Step 15 due to their difference in activity. Although a potential cross-contamination issue, it is also a personnel exposure issue.

Additional Points

Analysts should recognize that when performing gross α or gross β analysis directly on the air

particulate filters, the mass loading will have a significant effect on the reliability of the results when

they are compared to the total α or β analysis following radiochemical separations. Step 11 notes that

the analyst should compare the radiochemical specific analyses to the gross analyses and see whether

they are within a factor of two. If not, and if there are additional samples being analyzed that have

similar characteristics, a correction factor may need to be applied to the efficiency factor in the gross

analysis to adjust for sample interference with the gross measurement. 

It is important to remember also that gross α or gross β analysis by evaporation, following sample

digestion (Step 4), will result in a significant loss of volatile radionuclides (such as technetium and

iodine). 

Change in activity of samples from decay during transport may be significant depending upon the

radionuclide mix. If the time from completion of field sampling to sample receipt at a laboratory is

about 12 hours, any accumulated 222Rn progeny will have decayed to 210Pb (yielding negligible

activity due to its 22 y half-life). Any collected 220Rn progeny will be reduced by one-half (due to the

11-hour half-life of 212Pb). With an upper estimate of 3.5 pCi/m3

, 220Rn surface concentration for

most sites, ~210 pCi of 212Pb (ignoring decay while sampling) would be collected on the filter (for

a 60 m3 sample) and ~100 pCi (220 dpm) would be present after the 12-hour delay to begin the

laboratory’s gross beta analysis. The laboratory would calculate a gross beta concentration of ~3.5

pCi/m3

 (from 212Pb plus 212Bi and an additional contribution from 208Tl of about 36%) and ~1.5

pCi/m3

 gross alpha concentration from 212Po. Gamma-ray spectrometry may detect 212Pb, 212Bi and

208Tl at this concentration (depending upon total activity on particulate filter). 

Gross alpha and beta radioactivity contributions to these analyses due to airborne dust (generally

~100 μg/m3) from typical soil concentrations of 238U, 232Th, or 40K will be negligible for a 1-hour

sampling duration using either a high- or low-volume sampler.

Certain α- and β-emitting radionuclides have very low abundance γ rays. These γ rays are not

normally used for analysis of those radionuclides when trying to determine them at normal,

environmental levels. Thus, the gamma-spectrometry software may not have these γ rays in its

analysis library. It is recommended that a separate library for incident response samples be created

which has these low abundance γ rays. Table 5 provides some examples.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

32

TABLE 5 – Radionuclides with Low-Abundance Gamma Rays*

Radionuclide 89Sr 90Y 129I 210Po 226Ra** 228Th

Principal Decay βS βS βS αα α

Gamma, keV 909 2,186 40 (32 X-ray) 80.3 186 (262) 84

Abundance, % 9.6×10–3 1.4×10–6 7.5 (92.5) 1.1×10–3 3.3 (5×10–3) 1.21

Radionuclide 232Th 235U** 237Np 238Pu 239Pu 240Pu 241Am

Principal Decay α α α ααα α

Gamma, keV 911 

(from 228Ac)

186 (143,

163)

86.5 55.3 112.9 54.3 59.5

Abundance, % 27.2 54 (11, 5) 12.6 4.7×10–2 4.8×10–2 5.2×10–2 35.7

Radionuclide 241Pu 242Pu 243Cm 227Ac

Principal Decay βS α αβS

Gamma, keV 149 44.9 278 236

Abundance, % 1.9×10–4 4.2×10–2 14 11.5 *

 Values in parentheses represent the next most abundant photopeaks.

**Care must be taken with this identification as 226Ra and 235U gamma rays may not be resolved at this energy.

These gamma rays can be used for qualitative identification of these radionuclides. Their presence

in the gamma-ray spectrum should direct the analyst to perform chemical separations followed by

α- or β-specific detection.

Aluminum absorbers can be used to qualitatively identify the presence of beta-emitting radionuclides

based on the ability of their beta emissions to penetrate the aluminum. Thus if an aluminum absorber

of 6.5 mg/cm2

 thickness is used and the measured beta activity is reduced to background, one could

qualitatively state that the beta particle energy of the radionuclide is < 0.067 MeV. Conversely if the

absorber has little effect on the count rate, it can be stated that the beta particle energy is >0.067

MeV. Table 6 identifies some beta-only emitters with their energies and range in aluminum

absorbers. This technique is one option to help estimate the energy of the beta particle, which assists

in the identification of the beta-emitting radionuclide.

TABLE 6 – Beta “Only” Emitters

Radionuclide 241Pu 63Ni 129I 35S 99Tc 32P 90Sr/90Y

Maximum β Energy, MeV 0.021 0.067 0.150 0.167 0.294 1.711 (0.546)/2.28 [1]

Range [2], mg/cm2 for Eβmax 0.8 6.5 27 32 75 800 1,100

[1] Based on the sampling plus sample transit time 90Sr/90Y may be in secular equilibrium by the time any analysis is

started. Thus, the 2.28 MeV beta particle of 90Y will, most likely, be present.

[2] U.S. Department of Health, Education and Welfare (HEW). 1970. Radiological Health Handbook, p.123.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

33

No

.

12.

Any α β, or

γ> Table 7C or 7D

10- 4 ADL

Values

?

11. Routine gross "/$ by 

GPC on filter, gamma 

spec on charcoal cartridge 

for 131I

Yes

3.Gamma analysis

(0.5–2 hours each)

6.

Any α,

β, or γ> Table 7A 

or 7B 500-mrem

ADL Values

?

18.

Individual 

radionuclides 

> 10–4 risk

or sum of fractions

>1.0 

?

No

Yes

Air Filter Analysis — Low-Flow Sampler

• Uncharacterized source or area

decontamination

• Priority to those samples with highest activities

• Sample collected for 12 hours to 7 days

Yes

4. Dissolve entire filter

No 7. α analyses

8. β analyses

7. α analyses

8. β analyses

Yes

No

19.

Individual 

radionuclides 

> 10–6 risk

or sum of fractions

>1.0 

?

14. Dissolve 

entire filter

20.

Gross α/β

& γ results 

compare with sum

of activities

?

No

Yes

No

21. Recount all α, β, γ

radionuclides; 

re-evaluate results

23. Archive final 

sample forms

10.

Gross α/β

& γ results 

compare with sum

of activities

?

2. 

Gross α,

Gross β/γ, OR 

γ > Table 7A or 7B

500-mrem

ADL

?

No

Yes

Highest priority

(>500 mrem)

Second priority

(>10–4 risk)

Lowest priority

(>10-6 risk)

End result

Key

See accompanying tables 

for alpha and beta/gamma

concentrations, and 

numbered notes

Highest priority

(>500 mrem)

Second priority

(>10–4 risk)

Lowest priority

(>10-6 risk)

End result

Key

See accompanying tables 

for alpha and beta/gamma

concentrations, and 

numbered notes

13. γ-ray analysis

(on filter and cartridge)

13a. Cartridge and 

undigested filter samples 

from Scenario 1 

Yes

22. Notify IC of results and

any discrepancies

1.Rapid lab scan 

for gross α, β, or γ

5.Repeat gross 

α/β using GPC

16. β analyses

15. α analyses

17. γ analysis

(if not done on filter)

16. β analyses

15. α analyses

17. γ analysis

(if not done on filter)

13b. Previously digested 

samples from Scenario 1 

9. Verify all analyses 

completed. Compare 

individual results to 500-

mrem ADL

Figure 3 – Air Scenario 2 Analytical Flow

V. SCENARIO 2 (Priority to Air Samples with Highest Activities)
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

34

Notes to Scenario 2: Low-Flow Air Sampling 

Purpose: Source of contamination may not be completely identified during

early phase of event. 

Considerations: Samples may have been taken from an uncharacterized area.

Samples are taken in the intermediate to recovery phase of the

event. Priority to samples with highest activities (> 500 mrem AAL)

The samples may arrive over several days; those with the highest priority are always to be

analyzed first. Only after an analytical step or procedure has been completed for the highestpriority samples should lower-priority samples be addressed. Lower-priority samples (those

following the yellow and brown flow paths on this chart) may need to be stored for several days

until the highest-priority samples have been analyzed. The samples with the highest priority

(green path) will be the ones with the highest activity. Some of the information in Step 1 is

provided to the laboratory by the field sampling team.

A low-flow sampler 0.50 to 4.0 ft3

/min (1.4×10–2 to 1.1×10–1 m3/min) is used to obtain a

particulate sample over a longer time period (12 hours to 7 days, compared to Scenario 1 where

the sample collection is minutes to hours) to help ensure representative sampling. Of those

samples taken during the recovery phase of an event, many will be at areas distant from the

original event site. These samples will be used to determine if the 10-4 and 10-6 risk AALs are

exceeded (by comparison with their corresponding ADL values in Tables 8A and 8B). 

For low-volume samples, a two-inch filter is typically used, with an iodine cartridge following

the particulate filter (in series) when sampling for radioiodines is needed. However, when

different filter sizes are used, lab personnel must know if the shipped sample is only part of a

larger filter . For example, if a 4"-diameter circle is cut from 8×12" filter, the sample results must

be multiplied by 7.64 to correct for the activity on the whole filter. The sample chain-of-custody

form must specify if the field measurements were made on the entire filter, or just the portion

shipped, so that the lab measurements can be compared with the field measurements. This will

assist in getting insight into the quantity of short-lived radionuclides that may be present. It is

also important to know the composition of the filter medium so that appropriate steps can be

taken during the filter digestion process. It should also be established by this time in the event

if DRPs exist. Sub-sampling of the particulate filter must be done very carefully (if at all) to

avoid non-representative results.

Low-flow sampling taken over a long period (> 1 day) will collect larger air volumes and may

provide higher radionuclide activities on the collection matrices. This may provide a more

representative average concentration.

Many of the flow diagram shapes are color-coded to reflect the highest-priority analytical flow

path (green), intermediate (next important) flow path (yellow), or the lowest-priority flow path

(brown) based on the time needed to return the required analytical results to the IC. The

accompanying numbered notes are color-coded in the same fashion, as are the examples in

Appendix III. It is highly advisable to study the flow paths in color, as a black-and-white printing

may be confusing or ambiguous. 

1. Upon receipt, the laboratory will make a rapid scan with a hand-held instrument (or other

instrument capable of high sample scan throughput). The laboratory instruments used for this

purpose might include a survey meter (with alpha and beta channels) or a Geiger-Muller
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

14 This term describes the concentration of the radionuclides of interest in a thin slice of the entire cartridge width that

faces the inlet air flow. At low concentrations, this will usually be the case, but loading can be affected by humidity,

temperature, and presence of other gases that may be adsorbed by the cartridge. One technique that may avoid the issue

of face versus fully loaded is to “side count” the cartridge. The gamma spectrometry detector must be calibrated for this

special geometry.

35

(GM) counter with appropriately calibrated beta and gamma detector probes, or a microroentgen meter (gamma only). This step will be conducted in the laboratory initially with the

particulate filter in its container (e.g., a glassine envelope). The first measurement will be for

gross alpha (outside surface), beta and gamma to assess overall exposure and potential

contamination. Once it has been determined if any other precautions are necessary for direct

measurement (e.g., fume hood, protective breathing equipment, etc.), then the filter is

removed from its container so that the alpha measurement can be assessed more accurately.

Unless the identity of the radionuclide contaminant is known, the hand-held survey

instrument should be calibrated using a standard source (e.g., 241Am for α, 90Sr for β, or 137Cs

for β or γ) that will replicate the particulate filter geometry.

During this sample processing phase, special precautions should be taken to avoid sample

cross-contamination as well as laboratory contamination from samples that may have loosely

held particulate matter that is radioactive. 

Factors to consider when making the gross screening measurements:

• The solids loading (mg/cm2

) on the filter medium should be determined (by the

laboratory) in order to assess accurately the activities relative to background. This can

be done by taking the average mass of an unloaded filter and subtracting it from the final

mass of each filter received from the sample team. This mass can then be used to

estimate the normal concentration of naturally occurring radionuclides in airborne dust

and solids within a sampled area (including any unaffected areas). A dust concentration

of ~100 μg/m3 is typical for non-industrial areas due to terrestrial dust resuspension. (See

the discussion of naturally occurring radionuclides in terrestrial dust under “Additional

Points” following the notes to Scenario 1.)

• Iodine cartridges also must be counted by a gross gamma screen in order to be able to

assess the 500-mrem AAL (including decay correction to the midpoint of the sampling

interval for the 125I and 131I radionuclides). This is determined using the 500-mrem ADL

of 1.6×103, 240, and 1.2×103 pCi/m3 for 125I, 129I, and 131I, respectively (these are for the

sum of the individual iodines on the cartridge from the analysis of the iodine filter plus

the particulate filter), at the 500-mrem ADL. It is likely that an iodine cartridge will be

“face-loaded.”14 However, the laboratory must be able to confirm this assumption.

Cartridge orientation when counting, as well as proper calibration for that geometry, must

be ensured. If the radioiodines are detected on the cartridge, a gamma count of the

particulate filter should be performed to identify any additional radioiodine contribution

prior to assessing what AAL may have been exceeded.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

36

It is possible that noble gasses, such as krypton and xenon (if present from a nuclear

detonation or power plant accident), also would be captured on the iodine cartridge, and

thus the identifying gamma lines of the noble gas radionuclides should be in the gammaray library.

• Decay products of radium may be found on both the particulate filter and the iodine

cartridge. Change in activity of samples during transport may be significant depending

upon the radionuclide mix. An example of this occurs for radioactivity on an air filter

when the time from the end of sample collection to receipt at a laboratory is about 12

hours. Any collected 222Rn progeny will have decayed to 210Pb (yielding negligible

activity due to its 22 y half-life), since the decay chain is broken by 222Rn not being

collected on the filter. 

For 224Ra, the surface concentration existing naturally at many locations yields an air

concentration of 220Rn of 3.5 pCi/m3. This would yield about 2,100 pCi of 212Pb (ignoring

decay while sampling) on the filter (for a 600 m3 sample). Less than 1,000 pCi (#2,200

dpm) would remain during the laboratory’s gross beta analysis (when initiated ~12 hours

later). The laboratory would calculate a gross beta concentration of ~3.5 pCi/m3 from

212Pb plus 212Bi and a gross alpha concentration of ~1.75 pCi/m3

 from 212Po. Gamma-ray

spectrometry will detect 212Pb/212Bi at this concentration. 

• Gross alpha and beta radioactivity due to airborne dust (100 μg/m3

) from typical soil

concentrations of 238U, 232Th, or 40K may not be negligible for a 24-hour or longer

sampling duration using a high-flow sampler. Because this decision tree addresses the

late intermediate and recovery phases, when turnaround times (TATs) may be longer, it

may be desirable to wait (when permissible) 72 hours from the end of sample collection

before performing the gross alpha and beta analyses. Waiting 72 to 100 hours will allow

for decay of 212Pb and progeny, so that the radionuclides from the event will be measured

with greater precision by gross techniques.

• Ideally, laboratory screening of samples should be detailed enough to assess if there is

an absence of DRPs. If the screen is a single measurement taken on the entire sample,

this assessment may not be possible. If DRPs are detected/suspected, field personnel

should be notified.

• Tritium sampling of the aerosol at this stage of the event will most likely be unnecessary

as atmospheric moisture and precipitation will rapidly dilute any tritium present.

The presence of 208Tl is as good an indicator of the presence of naturally occurring

radionuclides as 212Pb, since the half-life of 208Tl is short and gamma yield (at 583 keV)

is relatively good.

2. A gross α/β screen is performed with a hand-held device to assess the activity level for

laboratory prioritization. The results of the gross α/β screen are compared to the ADLs for

the 500-mrem exposure level to assess the activity level for laboratory prioritization. If all
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

37

measurements are less than their respective ADL values, then the sample follows the lowerpriority path to Step 11.

If the gross α/β screen (performed with a hand-held laboratory device) exceeds any alpha or

beta radionuclide 500-mrem ADL, gamma spectrometry analysis is performed at Step 3. 

If the gamma spectrometry results for the iodine cartridge or the filter exceed the ADLs of

1.6×103

, 240, and 1.2×103 pCi/m3 for 125I, 129I, and 131I, respectively, then the filter and

cartridge should be processed along the higher-priority flow path with gamma spectrometry

analysis at Step 3. 

3. The entire filter should be counted by gamma spectrometry. The count time should be long

enough to meet the uMR in Tables 7C and 7D for the 500-mrem AAL. If a sample was taken

using a radioiodine cartridge, ensure that this is counted on a low-energy photon detector so

that the long-lived isotopes of iodine (that have low gamma-ray energies below 60 keV) can

be determined.

4. Effective sample digestion should use a fusion technique that uses a low-temperature flux

or else an acid digestion technique that ensures a single, homogeneous phase. If glass fiber

filters have been used, some form of fluoride treatment (for example, NaF fusion or HF

removal of silica are commonly used techniques) should be used to eliminate silica

precipitation later in the analytical process. Note that any method used to dissolve the filter

will reduce or eliminate the activity of any volatile or semi-volatile radionuclides present on

the filter. Therefore, analyses for radioisotopes of iodine, phosphorus, and sulfur will need

to be performed in a manner that prevents their loss during sample preparation and analysis.

Sufficient final volume of the digested sample should be saved for removal of subsequent

aliquants for specific alpha- and beta-emitting radionuclides. This should include an aliquant

that may need to be recounted by gamma spectrometry for a period of time sufficient to meet

the uMR in Tables 7C and 7D for the 500-mrem AAL. This count time will be much longer

than if the gamma-spectrometric analysis were performed on the entire filter. Ensure that the

calculation of the final activity of the sample corrects for that fraction of the digested solution

or filter actually used in the analysis.

5. A gross α/β analysis of the filter digestate is made at this point. The analytical method and

low-level radiation detection instrumentation should produce an improved detection capability and a reduced measurement uncertainty for these analyses compared to the survey

meter measurements of Step 1. These results supersede those obtained in Step 2.

6. The results of the gross α/β analyses from Step 5 and the gamma-spectrometric analysis from

Step 4 are compared to the 500-mrem ADL values in Table 7A and 7B. If no 500-mrem ADL

value is exceeded, then the sample follows the lower-priority sample queue (Steps 15, 16,

and potentially 17). Otherwise, alpha- and beta-specific analyses are started immediately

(Steps 7 and 8).
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

15 If counting were to take place within 72 hours of sampling, the radon progeny would still contribute to the gross alpha/

beta results, and the 1⁄2 value should be carefully examined because early gross count values could be artificially high.

38

NOTES: 

• Steps 7 and 8 should be performed concurrently. Although all the radionuclides listed in Table

3 are possible contaminants, perform those analyses that are most probable based on previous

samples and direction by the IC.

• Samples from the same event and area may be queued more accurately using the information

already obtained on the first batch of samples. For example, if 241Am is one of the known

contaminants, that analysis would be started first in Step 7.

7. These two steps are done in parallel to imp 8. rove TAT. Each analysis is performed to

determine if 500-mrem ADL values in Tables 7C and 7D have been exceeded. Priority

should be based on:

• IC input (when provided)

• Results from previous samples for this location or event;

• Gross analysis that yielded the greatest count rate above background; or 

• Results of gamma spectrometry from Step 3 (that may indicate certain low γ-yield

radionuclides).

9. Ensure that all analytical results are available for all of the radionuclides to be analyzed for

each sample. Select the corresponding 500-mrem ADL values for each of the radionuclides

analyzed and compare to the analytical results. Compute the sum of the fractions for all

radionuclides identified above their respective sample-specific critical values.

10. If the results of the analyses performed in Steps 7 and 8 exceed an individual 500-mrem ADL

(values are in Tables 7C and 7D) or if the sum of the fractions results are >1.0, go to Step 22.

The sum of the individual radionuclide concentrations should be approximately equal to the

respective gross activity concentrations (the rule of thumb is within a range of about half to

twice the respective gross value if the measurement is made more than 72 hours after sample

collection15) for each sample. Ensure that any dilution factors or sample splitting have been

taken into account. If there is a discrepancy between the sum of the individual results and the

respective gross results, there may be either missing radionuclides or an error in the analyses

since the gross results indicated activity above the 500-mrem AAL. This discrepancy should

be resolved by recount or re-analysis (Step 21).

11. The gross scan performed at the laboratory has identified these samples as being less than

or equal to the ADL corresponding to the 500-mrem AAL. A gross alpha/beta screen using

a GPC for a longer period of time (see Tables 7C and 7D) should be performed to get a more

accurate assessment of the sample activity.

The solids loading (mg/cm2) on the filter medium should be determined (by the laboratory)

in order to assess accurately the activities relative to background. This can be done by taking

the average mass of an unloaded filter and subtracting it from the final mass of each filter

received from the sample team. This mass can then be used to estimate the normal concentra-
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

39

tion of naturally occurring radionuclides in airborne dust and solids within a sampled area

(including any unaffected areas). A dust concentration of ~100 μg/m3

 is typical for nonindustrial areas due to terrestrial dust resuspension.

The exception to this flow path is for the iodine cartridge. If the iodine-cartridge screening

results indicate a decay-corrected concentration greater than a 500-mrem ADL for any iodine

isotope [e.g., 131I > 1.2×103 pCi/m3], go directly to Step 3 and gamma-count the cartridge and

filter (separately), regardless of the gross α/β result. This becomes a high-priority analysis

because this high an activity from short-lived radionuclides like 131I or the noble gases is

unlikely weeks after the event and should be immediately investigated. The longer-lived

iodine isotopes will not be detected by gross beta analysis. It is important therefore to assess

their presence by performing gamma spectrometry with a low-energy photon detector.

The screening results from Step 11 are compared to the values of 10!4 12. risk ADL for

• Gross alpha (from Table 7A), 

• Gross beta (from Table 7B), 

• Gamma isotopic, and 

• 131I for the cartridge [If radioiodines are detected on the cartridge, a gamma count of the

particulate filter should be performed to identify any additional radioiodine contribution

prior to assessing what AAL may have been exceeded].

See Table 12B for derivation of these ADL values. Values greater than the ADL will send

the sample to the high-priority path at Step 3. Samples below their respective ADLs are sent

to the lower-priority queue (Step 13) for gamma spectrometry analysis at a later time to

determine if the 10-6 risk ADL has been exceeded. It may be advantageous to use

simultaneous (e.g., a multi-chamber detector system) versus sequential gross alpha/beta

counting for longer time periods than for the previous screening measurements. This will

ensure that the counting time is sufficient to meet the uMR so that a valid comparison to the

ADL for the 10!4

 and 10!6 risk can be made.

A longer gamma spectrometry analysis (to meet the 10–6 13. risk MQOs) should be performed

to identify any gamma-emitting radionuclides that may have been undetected during the

gross screening analysis. The gamma spectrometry analysis using a low-energy photon

detector also should be performed on both the filter and any iodine cartridges that may have

been used in the sampling. Ensure that aliquant size and counting time are sufficient to meet

the uMR, so that a valid comparison to the ADL for a 10–6 risk AAL can be made.

13a. Samples from Radioanalytical Scenario I (Step 15) would feed into the analytical processing

scheme at this point and be ready for Step 13 if these samples have not yet been digested.

13b. Samples from Radioanalytical Scenario I (Step 17) would feed into the analytical processing

scheme at this point. Go to Steps 15, 16, and 17 if these samples already have been digested.

If the filter has not been counted by gamma spectrometry in Step 17 of Scenario 1 flow

diagram, longer count times will be required here.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

40

NOTES: 

• Steps 15, 16, and 17 should be performed concurrently. Although all the radionuclides listed

in Table 3 are possible contaminants, perform those analyses that are most probable based on

previous samples and direction by the IC.

• Samples from the same event and area may be queued more accurately using the information

already obtained on the first batch of samples. For example, if 241Am is one of the known

contaminants, that analysis would be started first in Step 15.

14. Samples in this step have gross α/β and γ isotopic activities less than the 500-mrem ADL and

consequently are a lower priority. When detectors are available, the entire filter should be

dissolved and aliquants apportioned for α and β analysis (with sufficient reserve aliquants

for analysis that may require either lower detectability or analysis for radionuclides not in

Table 3).

A fusion technique that uses a low-temperature flux, or an acid digestion that ensures a

single, homogeneous phase, should be applied. If glass fiber filters have been used, some

form of fluoride treatment (for example, NaF fusion or HF removal of silica are commonly

used techniques) should be used to eliminate silica precipitation later in the analytical

process. HF may be better for samples that only have alpha-emitting radionuclides because

its use minimizes the addition of other solid matter to the final counting form, which in turn

minimizes sample self-absorption. 

Sufficient final volume of the digested sample should be saved for removal of aliquants in

the future for specific alpha- and beta-emitting radionuclides. This should include an aliquant

that may need to be recounted by gamma spectrometry for a period of time sufficient to

achieve uMR for the 10–6 risk level. Ensure that the calculation of the final activity of the

sample corrects for that fraction of the original sample that was used for the analysis after

sample digestion. 

15. These three steps should be done concurre 16. 17. ntly. Prioritization of radionuclide-specific

analysis should be based on:

• IC input (when provided)

• Results from previous samples for this location or event; 

• Gross analysis that yielded the greatest count rate above background; or 

• Results of the gamma count from Step 13 (that may indicate certain low gammayield radionuclides).

Samples that were originally on the green path (high priority) may be routed here. They will

have been digested already. An aliquant of the digestate should be analyzed by gamma

spectrometry with a longer count than previously performed (long enough to meet the uMR

from Tables 8A and 8B). Ensure that aliquant size and counting time are sufficient to

determine if the ADL for the 10–6 risk AAL has been exceeded.

18. As the analytical values are obtained for each of the radionuclides in the tables, they are

compared with the 10–4 risk factor AAL. If more than one radionuclide is present above its

detection limit (i.e., critical level concentration), the sum of the fractions of the 10–4 risk

factor is used to assess whether the10–4 risk factor AAL is exceeded. If the sum of the
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

41

fractions exceeds 1.0 or an individual result exceeds the ADL, proceed to Step 9. Otherwise

go to Step 19.

Compare the sample results to the 10–6 19. risk factor ADL and the sum of the fractions (if more

than one radionuclide is present) to the 10–6 risk factor AAL. Any time the specific

radionuclide value for 10–6 risk factor ADL is exceeded, proceed to Step 9. Otherwise, the

sample processing continues with a lower priority at Step 20. Check to ensure that the gross

sample analyses agree with the sum of the individual analyses for that sample.

20. If there is poor agreement between initial gross screen and final radionuclide-specific

analyses, proceed to Step 21. If all comparisons have been made and found valid and results

are less than the applicable 10–6 risk factor ADL, and sum of the fractions of all radionuclides

above their detection limit is less than one, proceed to Step 22.

21. If the radionuclide specific analyses do not agree within the range of 0.5 to 2.0 times the

gross sample analysis for alpha and beta, respectively, the discrepancy should be resolved

quickly if possible.

The discrepancy should be quickly resolved, if possible. The samples either should be

recounted or reserved aliquants should be reprocessed to attempt to resolve the discrepancy.

If reprocessing resolves the discrepancy, re-evaluate the sample results against respective

ADL values, and then recalculate the sum of the fractions.

If reprocessing does not resolve the discrepancy, results should be reported with a notation

that the gross activity and radionuclide-specific activity sums do not agree.

22. Notify the IC of the sample results. Specific note should be made of any radionuclide that

exceeds an ADL or if the sum of the fractions exceeds 1.0. Any discrepancies between the

gross activity measurement and the sum of the final activity results should also be identified.

All results for samples are reported to the IC, along with any unresolvable discrepancies in

the analytical results.

23. The final sample test source should be archived so that their integrity is maintained and that

they are in a retrievable condition to reproduce counting. Any remaining final sample

fractions should be archived as well, e.g., remaining solution from the digestion of the air

filter. Provide electronic data deliverable (EDD) to field personnel or IC. 
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

42

VI. SCENARIO 3 (Radionuclides in Air Particulate Samples Have Been Identified)

1. 

What particles 

are emitted by the

sample

?

2α. 

Gross scan

α only

2β. Gross scan β only

2μ. 

Gross scan for

combination of 2 or 3

emission modes

9. Report results

to IC; note 

exceptions

3α.

Gross α >

2.3x10–3 

pCi/m3

?

3β.

Gross β

>0.21 pCi/m3

?

3μ.

Any 

α > 2.3x10–3, 

β>0.31 pCi/m3,

or γ>0.71

AAL

?

α

10. Verify all radionuclides have 

been accounted for; re-evaluate

results, check sum of fractions, 

or re-perform analyses

Yes

5α. 

All other α analyses 

required by IC

No Yes

Yes

No

No

No

6α. MQOs:

scale using tables 

5μ. 

All other radionuclide

analyses required by IC

5β.

All other β analyses 

required by IC

6β. MQOs:

scale using tables

6μ. MQOs:

scale using tables 

α, or β or γ

β

7. 

Any 

ADL exceeded? 

Final results agree

with screening

analyses

?

8.

Sum of fractions

<1.0

?

Yes

4α1.

Any α-specific

analysis > 

Table 8A

10-6 ADL

?

9. Report

to IC

Yes

No

4β1. 

Any β-specific

analyses > 

Table 8B

10-6 ADL

?

Yes

9. Report

to IC

4μ1.

Nuclidespecific analyses 

>Table 8A or 8B

10–6 ADL

?

No

9. Report

to IC

4α2. 

Any α-specific

analysis > 

Table 8A

10-4 ADL

?

4β2. 

ANY β-specific

analyses

> Table 8B

10–4 ADL

?

4μ2. 

Nuclidespecific analyses

> Table 8A or 8B

10–4 ADL

?

Yes

No

Yes

No No

Air Sample Scenario 3

• Known radionuclides

• Priorities established by Incident Commander

No

4α. Perform α-specific analysis 

following sample dissolution 

4β. Perform β-specific analysis 

following sample dissolution 

4μ. Perform nuclide-specific analysis

following sample dissolution

No

Yes

Yes

Yes

β emissions only

α emissions only

μ Multiple emissions

End result

Key

See accompanying tables 

for alpha and beta/gamma

concentrations, and 

numbered notes

9. Report results to IC

Figure 4 – Air Scenario 3 Analytical Flow
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

16 It should be noted that the evaluation for pure alpha or beta emitters should be done based on the principal particle

emission used for routine detection. This means that for the concentrations in air particulate samples below the 10–4 risklevel AAL, that 241Am would be considered “alpha only.”

43

Notes for Scenario 3: Contaminating Radionuclides Known

Purpose: Support the Specific Needs of the IC

For this scenario, “α” and “β” designate paths that are to be followed (and their associated notes)

when samples received from the field contain radionuclides that emit only alpha or only beta

particles, respectively, and “μ” designates samples that contain a gamma emitter or a mixture of

emitters (alpha or beta or gamma).

Scenario 3 takes place when the radioactive contaminants have been well characterized. Detailed

analyses are required for the radionuclide(s) known to be in the samples, and at the direction of

the IC. Thus, the radioanalytical process chart becomes more streamlined, and sample priority

is based upon what is needed by the Incident Commander at the time the samples are taken.

Either high- or low-activity samples may take priority.

Because the radionuclides are known, the gross-screening instruments should be calibrated for

the specific radionuclides of interest if possible. This allows rapid and more accurate assessment

of the activity before more time-consuming analytical separations are performed.

Many of the flow diagram shapes are color-coded to reflect the analytical flow path for various

combinations of decay modes (green for alpha, gray for beta, or brown for multiple emitters). The

accompanying numbered notes are color-coded in the same fashion, as are the examples in

Appendix IV. It is highly advisable to study the flow paths in color, as a black-and-white printing

may be confusing or ambiguous. 

1. The event that has taken place is now characterized and the radionuclide(s) of concern have

been identified. The flowchart is trimmed to deciding which of the three different

radionuclide emissions are present. The emission mode generally determines the final

radioanalytical method that will be used to assess the concentration. Generally, β-only

emitters will be analyzed by GPC or LSC (2β), α-only emitters by either GPC or alpha

spectrometry (AS) (2α), and any combination of the three types of emission by an appropriate

combination of alpha spectrometry, GPC, LSC, or gamma spectrometry (2μ). The choice is

determined by what is known about the event. If more than one type of radionuclide emitter

is present, the choice is to follow the multiple emissions mode path (2μ). The ranking of total

activity in the samples will be aided by sample gross screening when the samples are

received by the laboratory (see discussion in beginning of description for Scenario 2).

This path is selected only if radionuclides from the event are all pure α emitters.16 2α. The

samples still should be screened to distinguish high- from low-activity samples. Thus, the

instrument used to perform the screening analysis should be calibrated to permit specific

determination of the concentration of the radionuclide of interest.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

17 See previous footnote concerning the evaluation of pure alpha or beta emitters based on the principal particle emission.

44

This path is selected only if all radionuclides from the event are β emitters.17 2β. The samples

still should be screened to distinguish high- from low-activity samples. Thus, the instrument

used to perform the screening analysis should be calibrated using the radionuclide of interest.

2μ This path is selected only if the radionuclides from the event emit a combination of α, or β, .

or γ emitters. The samples still should be screened to distinguish high- from low-activity

samples. The instrument used to perform the screening analysis should be calibrated with the

radionuclides of interest.

3α. The purpose of this step is to distinguish high-activity samples from low-activity 3β. 3μ.

samples and to rank the samples in order of their activity level. The subsequent flow

paths would be selected based on the priority from the IC. Thus, it is important that

this screening method is able to distinguish high-activity samples from low-activity

samples in a reasonably short time. Table 14 in Appendix VI provides an insight into

the minimum detectable concentration (MDC) and 10% relative counting uncertainty

that can be achieved routinely using specified sampled volumes, and detector count

times using GPC. Although these MDCs are not equivalent and do not relate to a

specific AALs, they are low enough to be used for screening purposes. Once

classified as high or low analytical priority, the samples should be ranked based on

their gross activity measurements.

It may be advantageous to use simultaneous versus sequential gross alpha/beta

counting (e.g., using a multi-chamber detector system) for longer time periods than

for the previous screening measurements to be able to assess expeditiously if sample

activities are less than the 10!4

 and 10!6 risk ADLs and also to achieve the respective

uMR values.

The IC may stipulate an event-specific AAL, ADL, and uMR, whose values are based

on a fraction of the values found in Tables 8A and 8B. 

4α. 4β. The first analytical priority when this path is chosen is to determine the 4μ. known

contaminant(s) from the event. A radionuclide-specific method(s) should be chosen

for all previously identified radionuclides. This will usually require digestion of the

particulate filter as described in Scenario 1.

 The analytical methods chosen should be able to meet the uMR at the 10!6 4α risk AAL 1 4β1 4μ1

concentration (Tables 8A and 8B). This path would be chosen if the intent was to

look for unrestricted habitability. As results are validated, if the event-specific

NOTE: The flow of priority splits here. Either of the paths for the suffixes 1 or 2 may get

the priority. The priority is event-specific and determined by the IC. Suffix 1 designates

the 10–6 risk requirements, and suffix 2 designates other event-specific MQOs. Flow path

2 would be scaled to the appropriate ADL based on the 10–4 risk level.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

45

contaminant concentration is greater than its respective 10–6 risk ADL (Tables 8A or

8B), notify the IC. Otherwise, proceed with all other analyses and report results when

all are completed. 

4α This branch of the flow diagram would be chosen if the direction were to identify air 2 4β2 4μ2

particulate filters that have sufficient activity to cause exposure in excess of the 10–4

risk level, or other event-specific risk level defined by the IC. If the event-specific

contaminant is less than its respective ADL (based on scaling of concentrations and

in Tables 8A and 8B), then analysis for all other contaminants of concern should

proceed. If the event-specific contaminant concentration is greater than its respective

ADL for that event, notify the IC that this sample has exceeded the event-specific

AAL.

5α Perform all other radionuclide analyses required by the IC. . 5β. 5μ.

6α Select the ADL values from Tables 8A or 8B to be compared with the final analytical . 6β. 6μ.

concentrations for the air sample, and scale the ADL values to the incident-specific

AAL. For example, if the AAL required by the project was 10–5 risk for 232Th, start

with the 10–4 ADL value of 2.1×10–1 pCi/m3

 (from Table 8A) and divide it by 10. The

resulting value for the ADL will be 2.1×10–2 pCi/m3, with a uMR value of 3.8×10–3

pCi/m3. 

7. Start by comparing each individual radionuclide result with the incident-specific risk level

ADL values (see Tables 8A and 8B for the default values of 10!4 and 10!6). If the final

reviewed result for any single radionuclide exceeds the project-specific ADL, or the sum of

the fractions exceeds 1.0, report the results immediately to the IC.

8. Compare the radionuclide-specific results to the screening analyses and verify that no major

nuclide has been missed. Verify that the sum of the individual nuclide concentrations is

approximately equivalent to the gross activity concentration (a rule of thumb is within a

range of about half to twice the gross value). However, this may not hold true for low-energy

beta emitters, like tritium, if the screening measurement was made by GPC. This check will

ensure that the sum of the measurements compares reasonably to the total measured gross

activity. Activity concentrations due to decay products should be included in the verification.

If there is a discrepancy between the summed activity concentration of all statistically

significant individual nuclide concentrations (i.e., sum all results detected at levels greater

than the critical level, rather than the incident-specific discrimination limit), check for errors

and resolve any discrepancies prior to proceeding.

9. Two paths lead to this step: 

• In Steps 4α1, 4β1, and 4μ1, the result for the event-specific radionuclide exceeded the

10!4

 or 10!6 risk level, or

• All analyses have been completed, and the result is < 10!6

 risk factor. The priority path

was previously determined by the IC.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

46

10. If the results from the radionuclide-specific analysis and the gross measurement do not match

to within a factor of 0.5 to 2.0, then a potential mismatch exists between the individual

radionuclide concentration sum and the gross analysis (potentially missing a radionuclide

contributor. This would indicate a potential mismatch between the individual radionuclide

concentration sum and the gross analysis (potentially missing a radionuclide contributor).

This may require re-analysis starting with the gross-activity measurement.

It is possible that either a short-lived radionuclide decayed away prior to having been

analyzed, or a radionuclide analysis was missed. It may also be possible that a low-energy

alpha, beta, or gamma emitter was not detected during the gross analysis due to self shielding

effects. In either case, the discrepancy should be resolved, which may include specific

correlations for the radionuclides from this event.

Final results are then transmitted to the IC.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

47

APPENDIX I. Tables of Radioanalytical Parameters for Radionuclides of Concern

The following tables list the AAL, ADL, and uMR values for the radionuclides of concern. The tables

present gross screening and radionuclide-specific measurements for alpha and beta/gamma-emitting

radionuclides. Derivation of the ADL values for each of these tables can be found in Appendix VI.

Tables 7A and 7B show activities of specific radionuclides. These values were calculated based on

the Type I and Type II error rates presented in Appendix VI. 

The listed AALs are applicable as default values based on generic conversions of the dose level to

concentration in air for a specific radionuclide. The required method uncertainty and ADL will

change depending upon the acceptable decision error rate. The IC may provide incident-specific

AALs or decision error rates that would supersede these values. In this case, the laboratory will need

to develop new tables for all values, using the process described in Appendix VI.

TABLE 7A – Analytical Decision Levels (ADL) and Required Method Uncertainty Using Gross

Alpha Screening Methods

Radionuclide

(pCi/m3

)

2-rem 

AAL[1]

2-rem 

ADL

Required

Method

Uncertainty

(uMR) [3]

500-mrem

 AAL [1]

500-mrem

ADL

Required

Method

Uncertainty

(uMR) [3]

Gross α

Screen

0.70 0.35 0.21 0.17 0.085 0.052

 Am-241 0.70 0.35 0.21 0.17 0.085 0.052

Cm-242 11 5.5 3.3 2.8 1.4 0.85

Cm-243 0.97 0.49 0.29 0.24 0.12 0.073

Cm-244 1.2 0.60 0.36 0.29 0.15 0.088

Np-237 [2] 1.3 0.65 0.40 0.34 0.17 0.10

Po-210 16 8.0 4.9 3.9 2.0 1.2

Pu-238 0.62 0.31 0.19 0.15 0.075 0.046

Pu-239 0.56 0.28 0.17 0.14 0.070 0.043

Pu-240 0.56 0.28 0.17 0.14 0.070 0.043

Ra-226 [2] 7.0 3.5 2.1 1.8 0.90 0.55

Th-228 [2] 1.7 0.85 0.52 0.42 0.21 0.13

Th-230 0.66 0.33 0.20 0.17 0.085 0.052

Th-232 0.61 0.31 0.19 0.15 0.075 0.046

U-234 7.1 3.6 2.2 1.8 0.90 0.55

U-235 7.9 4.0 2.4 2.0 1.0 0.61

U-238 8.3 4.2 2.5 2.1 1.1 0.64

Notes:

[1] Derived air concentration yielding stated committed effective dose assuming a 365-day year. Child as

receptor. Value corresponds to solubility class having lowest value. 

[2] Includes decay products in the body for the calculation of concentration. 

[3] Required method uncertainty values are calculated for the 2-rem or 500-mrem AALs in Appendix VI.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

48

TABLE 7B – Analytical Action and Decision Levels (AAL and ADL) and Required Method

Uncertainty Using Gross Beta-Gamma Screening Methods

Radionuclide

pCi/m3

2-rem

AAL

[1]

2-rem 

ADL

Required

Method

Uncertainty

(uMR)

[3]

500-

mrem

AAL

 [1]

500-

mrem 

ADL

Required

Method

Uncertainty

(uMR)

[3]

Gross β Screen [4, 5] 420 210 130 110 55 33

Ac-227+DP [2] 0.43 0.22 0.13 0.11 0.055 0.033

Ce-141 1.8×104 9.0×103 5.5×103 4.5×103 2.3×103 1.4×103

Ce-144 1.3×103 650 400 320 160 97

Co-577 6.7×104 3.4×104 2.0×104 1.7×104 8.5×103 5.2×103

Co-60 2.2×103 1.1×103 670 550 280 170

Cs-134 3.3×103 1.7×103 1.0×103 820 410 250

Cs-137 1.7×103 850 520 430 220 130

H-3[3] 2.6×105 1.3×105 7.9×104 6.4×104 3.2×104 1.9×104

I-125 [6,7,4] 1.3×104 6.5×103 4.0×103 3.2×103 1.6×103 970

I-129 [6,4] 1.9×103 950 580 470 240 140

I-131 [6,4] 9.1×103 4.6×103 2.8×103 2.3×103 1.2×103 700

Ir-192 1.0×104 5.0×103 3.0×103 2.5×103 1.3×103 760

Mo-99 6.8×104 3.4×104 2.1×104 1.7×104 8.5×103 5.2×103

P-32 1.7×104 8.5×103 5.2×103 4.3×103 2.2×103 1.3×103

Pd-103 1.5×105 7.5×104 4.6×104 3.8×104 1.9×104 1.2×104

Pu-241 29 15 8.8 7.3 3.7 2.2

Ra-228 [2] 4.2 2.1 1.3 1.0 0.50 0.30

Ru-103 2.3×104 1.2×104 7.0×103 5.7×103 2.9×103 1.7×103

Ru-106 1.0×103 500 300 250 130 76

Se-75 5.0×104 2.5×104 1.5×104 1.3×104 6.5×103 4.0×103

Sr-89 8.4×103 4.2×103 2.6×103 2.1×103 1.1×103 640

Sr-902 420 210 130 110 55 33

Tc-99 5.0×103 2.5×103 1.5×103 1.3×103 650 400

Notes: 

[1] Derived air concentration yielding stated committed effective dose assuming a 365-day year. Child as

receptor. Value corresponds to solubility class having lowest value. 

[2] Includes decay products in the body for the calculation of concentration. 

[3] Required method uncertainty values are calculated for the 2-rem or 500-mrem AALs in Appendix VI.

[4] All nuclides can be collected on a fibrous or membrane air filter media except 3

H, 125I, 129I, and 131I in the

vapor states.

[5] Value determined excluding 227Ac and 228Ra. Sr-90 is used for gross beta screening because it is the most

restrictive in the table and commonly used for instrument calibration.

[6] These values are based on the vapor plus particulate dose rate.

[7] Several nuclides decay by electron capture (see Table 3). These radionuclides cannot be detected using

gross β analysis. The electron-capture decay leads to characteristic X-rays of the progeny nuclide. The

most effective way to detect the X-rays from these electron-capture-decay radionuclides is either with

a low-energy photon detector (LEPD) or a reverse electrode germanium detector N-type semiconductor

detector. The lower range of energy with these detectors is about 10 keV. 
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

49

TABLE 7C – Analytical Action and Decision Levels (AAL and ADL) and Required Method

Uncertainty Using Alpha Radionuclide Specific Methods

Radionuclide

(pCi/m3)

2-rem 

AAL

[1]

2-rem

ADL

Required

Method 

Uncertainty

(uMR)

500-

mrem

AAL

[1]

500-

mrem

ADL

Required

Method 

Uncertainty

(uMR)

Am-241 0.70 0.49 0.088 0.17 0.12 0.021

Cm-242 11 7.8 1.4 2.8 2.0 0.35

Cm-243 0.97 0.69 0.12 0.24 0.17 0.030

Cm-244 1.2 0.85 0.15 0.29 0.21 0.037

Np-237 [2] 1.3 0.92 0.16 0.34 0.24 0.043

Po-210 16 11 2.0 3.9 2.8 0.49

Pu-238 0.62 0.44 0.081 0.15 0.11 0.020

Pu-239 0.56 0.40 0.071 0.14 0.099 0.018

Pu-240 0.56 0.40 0.071 0.14 0.099 0.018

Ra-226 [2] 7.0 4.9 0.88 1.8 1.3 0.23

Th-228 [2] 1.7 1.2 0.21 0.42 0.30 0.053

Th-230 0.66 0.47 0.083 0.17 0.12 0.021

Th-232 0.61 0.43 0.077 0.15 0.11 0.019

U-234 7.1 5.0 0.89 1.8 1.3 0.23

U-235 7.9 5.6 0.99 2.0 1.4 0.25

U-238 8.3 5.9 1.0 2.1 1.5 0.26

Notes:

[1] Derived air concentration yielding stated committed effective dose assuming a 365-day year. Child as

receptor. Value corresponds to solubility class having lowest value. 

[2] Includes decay products in the body for the calculation of concentration. 

[3] Required method uncertainty values are calculated for the 2-rem or 500-mrem AALs in Appendix VI.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

50

TABLE 7D – Analytical Action and Decision Levels (AAL and ADL) and Required Method

Uncertainty Using Beta-Gamma Radionuclide-Specific Methods

Radionuclide

pCi/m3

2-rem

AAL

[1]

2-rem

 ADL

Required

Method

Uncertainty

(uMR)

[3]

500-mrem

AAL

 [1]

500-mrem 

ADL

Required

Method

Uncertainty

(uMR)

[3]

Ac-227+DP [2] 0.43 0.30 0.054 0.11 0.078 0.014

Ce-141 1.8×104 1.3×104 2.3×103 4.5×103 3.2×103 570

Ce-144 1.3×103 920 160 320 230 40

Co-57[6] 6.7×104 4.7×104 8.4×103 1.7×104 1.2×104 2.1×103

Co-60 2.2×103 1.6×103 280 550 390 69

Cs-134 3.3×103 2.3×103 420 820 580 100

Cs-137 1.7×103 1.2×103 210 430 300 54

H-3[3] 2.6×105 1.8×105 3.3×104 6.4×104 4.5×104 8.1×103

I-125[5] 1.3×104 9.2×103 1.6×103 3.2×103 2.3×103 400

I-129[5,6] 1.9×103 1.3×103 240 470 330 59

I-131[5] 9.1×103 6.4×103 1.1×103 2.3×103 1.6×103 290

Ir-192 1.0×104 7.1×103 1.3×103 2.5×103 1.8×103 310

Mo-99 6.8×104 4.8×104 8.6×103 1.7×104 1.2×104 2.1×103

P-32 1.7×104 1.2×104 2.1×103 4.3×103 3.0×103 540

Pd-103 1.5×105 1.1×105 1.9×104 3.8×104 2.7×104 4.8×103

Pu-241 29 21 3.7 7.3 5.2 0.92

Ra-228 [2] 4.2 3.0 0.53 1.0 0.71 0.13

Ru-103 2.3×104 1.6×104 2.9×103 5.7×103 4.0×103 720

Ru-106 1.0×103 710 130 250 180 31

Se-75 5.0×104 3.5×104 6.3×103 1.3×104 9.2×103 1.6×103

Sr-89 8.4×103 5.9×103 1.1×103 2.1×103 1.5×103 260

Sr-90[2] 420 300 53 110 78 14

Tc-99 5.0×103 3.5×103 630 1.3×103 920 160

Notes: 

[1] Derived air concentration yielding stated committed effective dose assuming a 365-day year. Child as

receptor. Value corresponds to solubility class having lowest value. 

[2] Includes decay products in the body for the calculation of concentration. 

[3] Required method uncertainty values are calculated for the 2-rem or 500-mrem AALs in Appendix VI.

[4] All nuclides can be collected on a fibrous or membrane air filter media except 3

H, 125I, 129I, and 131I in the

vapor states.

[5] These values are based on the vapor phase dose rate and would be applied to the cartridges only for

screening purposes.

[6] Several nuclides decay by electron capture (see Table 3). These radionuclides cannot be detected using

gross β analysis. The electron-capture decay leads to characteristic X-rays of the progeny nuclide. The

most effective way to detect the X-rays from these electron-capture-decay radionuclides is either with

a low-energy photon detector (LEPD) or a reverse electrode germanium detector N-type semiconductor

detector. The lower range of energy with these detectors is about 10 keV. 
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

51

TABLE 8A – Analytical Action and Decision Levels (AAL and ADL) and Required Method

Uncertainty at 10–4 and 10–6 Risk Using Alpha Radionuclide-Specific Methods

Radionuclide

pCi/m3

 10–4 Risk

AAL

[1]

10–4 Risk

ADL

Required

Method

Uncertainty

(uMR) 

[3]

10–6 Risk

AAL

[1]

10–6 Risk

ADL

Required

Method

Uncertainty

(uMR)

[3]

Am-241 0.33 0.23 0.042 3.3×10-3 2.3×10-3 4.2×10-4

Cm-242 0.62 0.44 0.078 6.2×10-3 4.4×10-3 7.8×10-4

Cm-243 0.34 0.24 0.043 3.4×10-3 2.4×10-3 4.3×10-4

Cm-244 0.35 0.25 0.044 3.5×10-3 2.5×10-3 4.4×10-4

Np-237 [2] 0.43 0.30 0.054 4.3×10-3 3.0×10-3 5.4×10-4

Po-210 0.86 0.61 0.11 8.6×10-3 6.1×10-3 1.1×10-3

Pu-238 0.24 0.17 0.030 2.4×10-3 1.7×10-3 3.0×10-4

Pu-239 0.22 0.16 0.028 2.2×10-3 1.6×10-3 2.8×10-4

Pu-240 0.22 0.16 0.028 2.2×10-3 1.6×10-3 2.8×10-4

Ra-226 [2] 0.44 0.31 0.055 4.4×10-3 3.1×10-3 5.5×10-4

Th-228 [2] 0.094 0.066 0.012 9.4×10-4 6.6×10-4 1.2×10-4

Th-230 0.36 0.25 0.045 3.6×10-3 2.5×10-3 4.5×10-4

Th-232 0.30 0.21 0.038 3.0×10-3 2.1×10-3 3.8×10-4

U-234 0.45 0.32 0.057 4.5×10-3 3.2×10-3 5.7×10-4

U-235 0.49 0.35 0.062 4.9×10-3 3.5×10-3 6.2×10-4

U-238 0.52 0.37 0.065 5.2×10-3 3.7×10-3 6.5×10-4

Notes:

[1] Morbidity for long-term inhalation. Value corresponds to solubility class having lowest value.

[2] Includes decay products in the body for the calculation of risk or concentration. 

[3] Required method uncertainty values are calculated for the 10–4 and 10–6 risk values in Appendix VI.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

52

TABLE 8B – Analytical Action and Decision Levels (AAL and ADL) and Required Method

Uncertainty at 10–4 and 10–6 Risk Using Beta-Gamma Radionuclide-Specific Methods

Radionuclide[2]

pCi/m3

10–4 Risk 

AAL

[1]

10–4 Risk 

ADL

Required

Method

Uncertainty

uMR

[3]

10–6 Risk

AAL

[1]

10–6 Risk

ADL 

Required

Method

Uncertainty

uMR

[3]

Ac-227+DP [ 4] 0.083 0.059 0.010 8.3×10-4 5.9×10-4 1.0×10-4

Ce-141 920 650 120 9.2 6.5 1.2

Ce-144 69 49 8.7 0.69 0.49 0.087

Co-57 [6] 3.3×103 2.3×103 420 33 23 4.2

Co-60 120 85 15 1.2 0.85 0.15

Cs-134 180 130 23 1.8 1.3 0.23

Cs-137 110 78 14 1.1 0.78 0.14

H-3 Vapor 1.5×104 1.1×104 1.9×103 150 110 19

I-125 [5] 1.2×103 850 150 12 8.5 1.5

I-129 [5, 6] 200 140 25 2 1.4 0.25

I-131 [5] 640 450 81 6.4 4.5 0.81

Ir-192 510 360 64 5.1 3.6 0.64

Mo-99 2.6×103 1.8×103 330 26 18 3.3

P-32 890 630 110 8.9 6.3 1.1

Pd-103 7.0×103 4.9×103 880 70 49 8.8

Pu-241 14 9.9 1.8 0.14 0.099 0.018

Ra-228 [4] 0.28 0.20 0.035 2.8×10-3 2.0×10-3 3.5×10-4

Ru-103 1.2×103 850 150 12 8.5 1.5

Ru-106 56 40 7.1 0.56 0.40 0.071

Se-75 2.5×103 1.8×103 310 25 18 3.1

Sr-89 410 290 52 4.1 2.9 0.52

Sr-90 [4] 29 21 3.7 0.29 0.21 0.037

Tc-99 330 230 42 3.3 2.3 0.42

Notes:

[1] Morbidity for long-term inhalation. Value corresponds to solubility class having lowest value.

[2] All nuclides can be collected on a fibrous or membrane air filter media except 3

H, 125I, 129I, and 131I when

their chemical form is in the vapor (vap) state. It is possible for iodine to be in the particulate (part) form.

Note the differences in concentrations for the respective ADL values.

[3] Required method uncertainty values are calculated for the 10–4 and 10–6 risk values in Appendix VI.

[4] Includes decay products in the body for the calculation of concentration. 

[5] These values are based on the vapor phase dose rate and would be applied to the cartridges only for

screening purposes.

[6] Several nuclides decay by electron capture (see Table 3). These radionuclides cannot be detected using

gross β analysis. The electron-capture decay leads to characteristic X-rays of the progeny nuclide. The

most effective way to detect the X-rays from these electron-capture-decay radionuclides is either with

a low-energy photon detector (LEPD) or a reverse electrode germanium detector N-type semiconductor

detector. The lower range of energy with these detectors is about 10 keV. 
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

53

APPENDIX II. Example of High-Concentration Air Particulates (Radioanalytical

Scenario 1)

Description

Air samples have been taken in the vicinity of a detonation where it is suspected an RDD has been

used. Initial field readings show indications of radioactivity although no identification of radionuclides has been made. The sequence of events in the laboratory assumes a single analyst following the

analytical flow chart, under conditions of a single sample process stream.

Event Sequence

The incident response organization has just established a field office for coordinating the response

efforts, including a laboratory project manager who reports to the Incident Commander (IC). At 1200

hours of Day 1, the incident response team sends three air particulate samples and three iodine

cartridge samples from areas they believe to have the highest concentrations of airborne particulate

radionuclides based on the field measurements of these samples. The samples arrive at the laboratory

three hours later: it is Day 1, 1500 hours.

Analysis Paths

Field sampling personnel have noted on the chain-of-custody (COC) form that the samples were

taken at a flow rate of 4.0 cfm for 1 hour, yielding a total volume of air sampled of 6.8 m3. Field

measurements of the filter surface using a hand-held alpha probe and a GM detector calibrated with

241Am for gross alpha and 137Cs for gross beta and gamma, respectively, are noted in the tables below.

 Step 1. The lab performs a receipt survey of the samples using hand-held instruments for alpha,

beta, and gamma. The data produced by the lab measurements are also listed in the tables below.

Filter ID

Gross Alpha,

cpm (Field)

Gross Alpha,

cpm (Lab)

Gross Beta,

cpm (Field)

Gross Beta,

cpm (Lab)

Gross gamma,

μR/h (Field)

Gross Gamma,

μR/h (Lab)

1 70.0 25.4 46.0 9.0 53 37

2 8.0 1.3 15.8 8.3 51 37

3 1.8 1.2 15 8.2 50 37

Background 1.5 1.1 15 8.1 50 36

Cartridge ID

Gamma

spectrometry Results Gross Gamma, μR/h

1 No 131I identified 41

2 No 131I identified 38

3 No 131I identified 36

Background 40K 36

The number of samples have been minimized and the screening processes have been simplified in

this example. In an actual event, the number and complexity of samples will be much greater than

identified here.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

18 The detection efficiencies for the laboratory hand-held instruments used in this example are 0.1 for gross alpha and

0.3 for gross beta.

54

When the field measurements are compared to the lab measurements, it appears that the alpha and

beta emission rates have both decreased significantly during transport, indicating that there are shortlived emitters present. Given the similar gamma-count rates between the background and the

measurements of both the particulate filters and the iodine cartridges, there does not appear to be a

significant concentration of gamma emitters present. It is not clear whether the short-lived radionuclides are radon-decay progeny, radionuclides of concern related to the incident, or both. It is Day 1,

1515 hours.

Step 1a Filters 1, 2, and 3. If the laboratory value for the gross alpha on Filter 1 is used to

calculate18 pCi/m3, we find:

[25.4 1.1] cpm

(0.1[cpm / dpm]) 2.22 dpm / pCi)

1

6.8 m3 16.1 pCi / m − 3×

× =

(

This value exceeds all the 2-rem ADL values for the alpha-emitting radionuclides shown in Table

7A.

For the beta value, we find

[9.0 8.1] cpm

(0.3 [cpm / dpm]) 2.22 dpm / pCi)

1

6.8 m3 0.20 pCi / m − 3×

× =

(

which is below all the 2-rem and the 500-mrem ADL values for the beta-emitting radionuclides in

Table 7B (with the exception of 227Ac which is a 235U decay product and based on the scenario

evidence 235U was not a possibility).

The dose rate in μR/h is at the background level.

Filter 1 gets the red path for processing (Step 2), with the additional input that beta and gamma

analyses have no significant contribution to the total activity.

For Filter 2, the gross alpha values yield 0.13 pCi/m3, which is less than the 2-rem ADL gross alpha

value but greater than the gross-alpha 500-mrem ADL value in Table 7A. Following the Scenario

1 flow chart (Figure 2), because the gross alpha is between 500 mrem and 2 rem and the gross betagamma is insignificant. The filter should be analyzed as a second priority for all analytes starting at

Step 4.

For Filter 3, the concentration for alpha is 6.6×10–2, which is less than the 500-mrem ADL for alpha

emitters. Thus, this sample analysis would be continued as a second priority at Step 13.

Step 1b. No samples have been taken for tritium analysis.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

55

Step 1c. Cartridges 1, 2, and 3. The gamma-ray spectrometer used for analysis of these cartridges

is calibrated down to 25 keV. It is determined that the uMR values for the three iodine radionuclides

have been met based on the gamma spectrometry count time. Go to Step 3b. It is Day 1, 1530 hours.

Step 2, Filter 1. The microR-meter indicates activity at about the background level. Filter 1 is

counted by gamma spectrometry for 15 minutes. The filter is next counted on the GPC for 10

minutes (See Table 9). It is determined that the uMR values for gross alpha, gross beta and gammaspecific analyses by screening techniques (Tables 7A and 7B) have been met based on the gamma

spectrometry and GPC count times. Laboratory personnel begin to review the sample results; go to

Step 3a. It is Day 1, 1550 hours.

Step 3a, Filter 1. No gamma-ray peaks above their respective critical levels for the radionuclides

of concern are identified by the software. The GPC analysis results on the entire filter are 15.5

pCi/m3 gross alpha, and 2.0 pCi/m3 gross beta. Sample stays on the high-priority path at Step 4, and

a preliminary report is sent to the IC notifying the IC of the high result for this filter by laboratory

screening analyses.

Step 3b, Cartridges 1, 2, and 3. There were no samples submitted for tritium analysis, and all the

iodine cartridges have concentrations for the three iodine radionuclides less than their respective 

500-mrem ADL values. These samples should be archived until a longer gamma count can be

performed (Step 13).

Step 4, Filter 1. Filter 1 is dissolved using HF digestion that completely solubilizes the filter

material. Laboratory personnel have visually checked the final solution to ensure that no visible

particulate matter is present. Aliquants of the final solution are taken for gross alpha/beta, beta

emitters and alpha isotopic (radium plus uranium and the transuranic elements) analysis. An aliquant

of the remaining solution is archived for any additional analyses (like a follow-up gamma-ray

analysis) that may be required. It is Day 1, 2145 hours.

Step 5, Filter 1. Because the gross alpha 2-rem AAL was exceeded for Filter 1, an aliquant of the

dissolved filter solution is analyzed for gross alpha/beta by GPC. The alpha result is 20.1 pCi/m3,

beta result is 8.2 pCi/m3 . This confirms the results from the rapid analysis of the filter with survey

instruments. Note: The sample has been counted about 4 hours after the fusion step has occurred so

that radium progeny will have the opportunity to build in. It is Day 2, 0100 hours

Step 6, Filter 1. The values for gross beta and gross gamma do not yield a ratio of greater than 2.5.

Therefore, there is no indication of the presence of 90Sr at this time. Sample processing should

proceed with alpha analysis started first and the beta emitters next. Proceed to Steps 8 and 9.

Step 7, Filter 1. The analysis of the digestate for this filter for beta emitters is still a high priority

due to the gross alpha activity. The sample should be analyzed eventually for 90Sr.

Steps 8 and 10, Filter 1. The beta and gamma analyses are not above the 500-mrem AAL. The

significant decay of activity determined in the field vs. the laboratory indicates the short-lived beta

components may be progeny of radium. An analysis of the digestate aliquanted for archiving is

counted by gamma spectrometry for 90 minutes.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

56

Step 9, Filter 1. This sample should be given the top priority for alpha analyses. Analysis for

transuranics, radium, and uranium would be started before the analyses in Steps 8 and 10. 

 The only alpha emitter identified is 226Ra, at a concentration of 15 pCi/m3 Step 11, Filter 1. .

Subsequent beta analyses do not identify any other beta emitters in Table 8B. However, the longer

gamma spectrometry count time of the archived digestate portion will identify the gamma rays from

214Pb/ 214Bi. This result is consistent with radiological decay of 226Ra. The required relative method

uncertainty for radium are met (<13%). The result exceeds the 2-rem ADL (i.e., 15 pCi/m3

 is greater

than the ADL of 4.9 pCi/m3). The sum of the fractions of these beta emitters is unnecessary as the

dose is accounted for in the 226Ra activity. It is Day 2, 0800 Hours.

 The IC is notified that a 2-rem AAL has been exceeded on Filter 1for 226 Step 12, Filter 1. Ra. The

only radionuclides present are 226Ra and its decay products. It is Day 2, 1200 hours.

Step 13, Filters 2 and 3. Filters 2 and 3 are counted by gamma spectrometry for 2 hours. Gammaray peaks from 214Pb and 214Bi are observed as they have now had a significant “in-growth” period.

The GPC count time for gross alpha/beta has been 90 minutes. The count times have been long

enough for each screening analysis to meet the uMR values cited in Tables 7A and 7B for the 500 -

mrem ADL values.

Step 14, Filters 2 and 3. The GPC results are gross alpha 0.15 and 0.050 and gross beta 1.1 and 0.60

pCi/m3, respectively for Filters 2 and 3. Filter 2 takes a second-priority flow path at Step 4 while

Filter 3 is relegated to Step 15.

Step 4, Filter 2. Filter 2 is dissolved using a low-temperature flux fusion technique that completely

solubilizes the filter material. Laboratory personnel have visually checked the final solution to ensure

that no visible particulate matter is present. Aliquants of the final solution are taken for gross

alpha/beta, beta emitters and alpha isotopic (radium plus transuranic elements) analysis. An aliquant

of the remaining solution is archived for any additional analyses (like a follow-up gamma-ray

analysis) that may be required.

Step 5, Filter 2. Because the gross alpha 500-mrem AAL was exceeded for Filter 2, an aliquant of

the dissolved filter solution is analyzed for gross alpha/beta. The gross alpha result is 0.25 pCi/m3

and gross beta is 1.4 pCi/m3. This confirms the results from the filter analysis. Note: The sample has

been counted about 4 hours after the dissolution has occurred so that short-lived progeny will have

had the opportunity to build in.

Step 6, Filter 2. The ratio of the gross beta to gamma activity is much less than 2.5, based on

laboratory protocols for this comparison. Sample processing proceeds to Steps 8, 9, and 10.

Step 7, Filter 2. This step is a low priority because there is no indication of the presence of

strontium. The sample eventually should be analyzed for 90Sr.

Step 8, Filter 2. The beta analyses are a secondary priority as they are possibly above the 500-mrem

PAG AAL. Analysis will be started first for 226Ra as this has already been identified as the main

contaminant.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

57

Step 9, Filter 2. As the gross alpha was above the 500-mrem ADL, the alpha emitters analysis gets

the focus (226Ra is started first as it has already been identified). The beta emitters aliquant is started

shortly after. The results for Filter 1 have indicated that radium progeny were present in this sample.

Analysis for transuranics also proceeds at this point. The uMR values for all the alpha emitters have

been achieved.

 Gamma spectrometry count time is 2 hours. The uMR Step 10, Filter 2. values for all the gamma

emitters have been achieved.

 The analysis results from Filter 2 show the concentration of 226Ra is 0.32 pCi/m3 Step 11, Filter 2. .

Note: The sample has been counted about 4 hours after the dissolution has occurred so that progeny

have had some opportunity to build in. (For this example, re-analysis at Step 16 is unnecessary.)

 The IC is notified that the only radionuclides present are 226 Step 12. Ra and its decay products.

Step 15, Filter 3. Filter 3 is archived for analysis at a later time. Store the filter in a closed container

to avoid cross-contamination from other higher activity samples based on the presence of 226Ra. 

Step 16. Whenever on the green path and this step has been reached, and an activity that exceeds the

ADL for 500 mrem or 2 rem is determined, the laboratory staff need to assess the discrepancy

between the radiochemical separation value being above the action level and the original screening

value being below the action level.

Step 17. The final sample test sources are archived, as is the residual solution from the fusion of the

filter.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

58

APPENDIX III. Example of Air Particulate Filters Contaminated at Less than 2 rem

(Radioanalytical Scenario 2)

Description

Three weeks ago, a terrorist group detonated an RDD (using several pounds of dynamite) on the roof

of an office building in an urban area. The radionuclides that were identified during the early phase

of the event were 226Ra, 137Cs, and 90Sr. The event sequence in the laboratory assumes a single analyst

following the analytical process chart, under conditions of a single sample process stream.

Event Sequence

The event occurred at 1200 hours on Day 1. Three radionuclides were identified in the first 36 hours:

226Ra, 137Cs, and 90Sr. Recovery activities have been proceeding as expected. The current samples are

from areas that have been decontaminated, and ambient air analysis is being performed to assess

unrestricted use. It is now 22 days after the detonation, no other radionuclides have been detected,

and six samples have been collected by a field team. The sampling location was 10 miles downwind

of the RDD site. Samples were taken at a flow rate of 2 cfm for 6 hours, starting on Day 21 at 1200

hours. 

The samples arrive at the laboratory on Day 22 at 1600 hours.

Analysis Paths

Step 1, Filters and Cartridges 7, 8, and 9. The three samples are surveyed upon arrival using a

micro-R or survey meter yielding the following results for alpha, beta and gamma:

Filter ID

Gross Alpha,

cpm (Field)

Gross Alpha,

cpm (Lab)

Gross Beta,

cpm (Field)

Gross Beta,

cpm (Lab)

Gross gamma,

μR/h (Field)

Gross Gamma,

μR/h (Lab)

7 16.9 1.4 72 14 50 36

8 16.5 1.1 70 13 50 36

9 60 11.0 306 14 53 39

Background 1.5 1.1 15 8.1 50 36

Cartridge ID

Gamma spectrometry

Results Gross Gamma, μR/h

7 40K 36

8 40K 36

9 214Pb/ 214Bi, 40K 38

Background 40K 36

The number of samples have been minimized and the screening processes have been simplified in

this example. In an actual event, the number and complexity of samples will be much greater than

identified here.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

19 The efficiency of detection for the laboratory hand-held instruments used in this example are 0.1 for gross alpha and

0.3 for gross beta.

59

 Sample dose rates are measured using a survey meter19 Steps 2 and 3, Filters 7, 8, and 9. , and the

results of the measurements are used to calculate the concentrations. (Note that because the

radionuclides are now known, the survey meter was calibrated using a 230Th source whose energy

is very similar to 226Ra.)

An example of the calculation used by the laboratory for gross alpha on Filter 9 is:

[11.0 1.1] cpm

(0.1[cpm / dpm]) 2.22 (dpm / pCi)

1

20.38 m3 2.2 pCi / m − 3×

× =

This value exceeds the 500-mrem ADL for 226Ra of 0.90 pCi/m3 (Table 7A), but does not exceed the

2-rem ADL value of 3.5 pCi/m3. This sample stays on the green path for analysis.

The gross alpha and beta activities for Filters 7 and 8 are 0.066 and 0.000 pCi/m3

 (alpha) and 0.43

and 0.36 pCi/m3

 (beta), respectively. After comparing these results to the ADL values in Tables 7A

and 7B, it is clear that analysis of Filters 7 and 8 will be resumed at Step 11 at a later time.

The iodine cartridges are analyzed by a short count using gamma spectrometry. No iodine activity

is found on any of the cartridges (this would be expected based on the radionuclides found during

the early phase of the incident). It is Day 22 1630 hours.

Step 3, Filter 9. The filter is counted on the gamma-ray spectrometer for 30 minutes to meet the uMR

value of 0.71×AAL (500-mrem) for the gamma emitters. The iodine cartridges are counted on their

side in a calibrated geometry to meet the uMR values for iodines in Table 7B. Both the filter and the

cartridge for Filter 9 have measurable levels of 214Pb/214Bi. Although these radionuclides are not

directly used in risk assessment, their elevated activities indicate the presence of 226Ra. 

It is Day 22 at 1800 hours.

Step 4, Filter 9. The filter is dissolved using an HF dissolution technique. The residual HF is driven

off and the sample volume reduced to about 50 mL. Digestion is completed on Day 22 at 2200

hours.

Step 5, Filter 9. A 10-mL aliquant of the Filter 9 digestate is evaporated on a planchet for gross

alpha/beta analysis by GPC. Making the appropriate correction for the fraction of total taken for

analysis, the count time is 120 minutes to achieve the uMR value in Table 7A. (Note: Sufficient time

has elapsed since sampling to allow for the decay of all unsupported decay products.) It is Day 23,

0100 hours.

Step 6, Filter 9. The concentration for gross alpha is calculated from the sample activity as 2.8

pCi/m3 and the concentration is greater than the 500-mrem ADL for 226Ra (from Table 7A). This

value supersedes the previous gross alpha measurement made directly on the filter. The gamma

spectrometry result from Step 3 on Filter 9 has a 137Cs peak and the concentration calculated from
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

60

that peak area is 100 pCi/m3 This sample analysis remains on the green path due to the alpha activity

exceeding the 500-mrem PAG value.

Steps 7, 8, and 9, Filter 9. Based on the historical assessment of the incident, the analyses for the

three radionuclides already identified (226Ra, 137Cs, and 90Sr) would be the priority. Aliquants of the

final solution from the digestion are taken for analysis of the other listed beta emitters and

transuranic elements (the other gamma emitters would have been determined when the 137Cs was

determined in Step 3). The remaining solution is to be archived for any additional analyses that may

be required. Aliquanting is completed and priority analyses are started. Other analyses are started

when the priority analyses are completed. It is Day 23, 0130 hours.

 The values for the radionuclides identified from the incident are 226Ra (1.8 pCi/m3 Step 10, Filter 9. ),

137Cs (100 pCi/m3

) and 90Sr (2.0×10–3 pCi/m3). The result for 226Ra is above the 500-mrem ADL

(Table 7C) while the values for 137Cs and 90Sr are less than the 500-mrem ADL(Table 7D). The

results compare favorably with the original laboratory gross activity measurements; however, the 2-

rem AAL may have been exceeded. Whenever an individual ADL is exceeded, or the sum of the

fractions exceeds 1.0 at any decision level, the same criteria should be evaluated at the next higher

action level to determine whether the radionuclide-specific data was exceeded. This is particularly

important for the sum of the fractions. In cases where the next highest action level has been

exceeded, the IC should be notified immediately.

The sum of the fractions (based on the 2-rem AAL values in Tables 7C and 7D) is: 

Sum = (1.8/7.0) + (100 / 1.7×103

) + (2.0×10–3/4.2×102) 

= 0.26 + 0.059 + 4.8 ×10-6 = 0.32

The sum of the fractions does not exceed the 2-rem AAL. The IC is notified of the final results.

The analyses are completed on Day 23, 0430 hours.

Step 11, Filters 7 and 8. These analyses were started about 10 hours after the samples were initially

screened by laboratory personnel. Each filter is analyzed using GPC for 4 hours. The iodine

cartridges are counted for four hours by gamma spectrometry. All uMR values are achieved using these

count times. It is Day 23, 0630 hours.

Step 12, Filters 7 and 8. The individual activity values are given below, and these do not exceed

the gross alpha, gross beta, or iodine 500-mrem ADL values. It is Day 23, 0700 hours.

Filter Gross Alpha Gross Beta Iodine Cartridges

7 0.077 0.50 No iodine isotopes above the critical level

8 0.052 0.33 No iodine isotopes above the critical level

Step 13, Filters 7 and 8. Based on the low gross gamma screening value for Filters 7 and 8, a 4-hour

gamma spectrometry analysis is performed. Cs-137 is identified in Filter 7 at 0.55 pCi/m3; but no

activity other than that expected from background naturally occurring radioactive materials (NORM)

is found in Filter 8. It is Day 23 1100 hours.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

20 See Appendix VI for a discussion of critical level.

61

Step 13b, Filters from Scenario 1. No filters have been carried over from the earlier part of this

event (Scenario 1 for this event). Step 17 is not necessary.

Step 14, Filters 7 and 8. Filters 7 and 8 are dissolved using an HF dissolution technique. The

residual HF is driven off and the sample volume reduced to about 50 mL. It is Day 23 1530 hours.

Steps 15 and 16, Filters 7 and 8. Based on the historical identification of radionuclides from this

incident, analyses for 226Ra and 90Sr (137Cs has already been determined) begin first. Aliquants of the

final solution from the digestion are taken for alpha and beta emitters. The remaining solution is to

be archived for any additional analyses that may be required.

Step 17, Filters from Scenario 1. None.

Step 18, Filters 7 and 8. The values for the radionuclides identified from the incident are: 

• Filter 7: 137Cs (0.55 pCi/m3

), 226Ra (0.0051 pCi/m3), and 90Sr less than its critical level20 (actual

value is 1.6×10–3 pCi/m3) [proceed at Step 9].

• Filter 8: All values are less than their respective critical levels [proceed at Step 19].

All radionuclides on both filters are below their 10–4 risk ADL values. Filter 7 226Ra is above the 10–6

risk ADL value (0.0031 pCi/m3) . The sum of the fractions for the 10–4 risk factor (note that the AAL

values taken from Tables 8A and 8B are used to calculate the sum of the fractions and not the ADL

values) is: 

Sum = (0.55/ 110) + (0.0051/0.44) +(1.6×10–3/29) 

= 0.0050 + 0.1159 + 0.000055 = 0.13

Filter 7 follows the flow at Step 9. Filter 8 is evaluated at Step 18 at some time in the future. It is

Day 24, 0230 hours.

Step 9, Filter 7. The analyst has checked that all analyses have been completed and the results have

been compared to their respective 10–4 ADL values. (Sum of the fractions at 10!6 risk level does not

need to be verified because 226Ra already exceeds the 10!6

 risk.)

 Only 137Cs and 226 Step 10, Filter 7. Ra have been identified in this sample. The result compares

favorably with the original laboratory gross activity measurement, and is between the 10–4 and 10–6

risk AAL. However, the gross alpha and beta results do not compare favorably with the final sum

of the radionuclide activities determined, and the sum of the fractions does not exceed the 10–4 risk

AAL. The gross alpha measurement at Step 5 was 0.097 pCi/m3 and the final result was 0.0051

pCi/m3. The radionuclide results are within the range of 0.5 to 2 times the gross alpha count

measurement, but just barely. The data reviewer decides to investigate ( Step 21).

Step 21, Filter 7. The data are reviewed by the data validator who notices that the gross alpha counts

on the digestate from Step 5 are so close to background that the gross result is significantly affected

by the background count rate. Even though the final result is much lower than the screen, it would

be difficult in this sample to distinguish between real radium counts and background counts. It is
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

62

decided that this discrepancy is within the bounds of the analysis uncertainty at this level, and it will

be reported in the comments section of the final report. Go to Step 22.

 Filter 8 is below the 10–6 Step 19, Filter 8. risk factor ADLs for the radionuclides determined. Go

to Step 20.

Step 20, Filter 8. The radionuclide-specific results are consistent with the gross analyses.

Step 21, Filter 8. As all results corresponded to the initial laboratory gross screening, no further

action is needed. 

 Results for Filter 9 are reported immediately after ascertaining that 226 Step 22, Filters 7, 8, and 9. Ra

and 137Cs are above the 500-mrem ADLs, and thus above the AAL (see Step 10 Filter 9). The

discrepancy between the gross alpha and sum of alpha emitters is noted. Results for Filters 7 and 8

are reported about 24 hours later. For Filter 7, the 10–6 risk AAL for 226Ra has been exceeded. For

Filter 8 all radionuclide concentrations analyzed for are less than the 10–6 risk AAL values. It is Day

24 at 0400 hours.

Step 23, All final sample test sources. The final sample test sources and any residual solution from

the sample dissolution should be archived in case additional analyses are required.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

63

APPENDIX IV. Example of Air Particulate Filters With Known Radiological Contaminants (Radioanalytical Scenario 3)

Description

Air samples have been taken in the vicinity of an event in which a radioactive aerosol is suspected

to have been sprayed from an airplane. Initial field readings show indications of alpha activity

although no definite identification of radionuclides has been made. The sequence of events in the

laboratory assumes a single analyst following the analytical process chart, under conditions of a

single sample process stream.

Event Sequence

The incident response team has established a field office for coordinating the response efforts,

including a laboratory project manager who reports to the Incident Commander (IC). At 1200 hours

of Day 1, the incident response team sends three air particulate samples and three iodine cartridge

samples to the laboratory. These samples are from areas they believe to have the highest concentrations of airborne particulate radionuclides based on the field measurements of these samples. These

first samples arrive at the laboratory 6 hours later. While the first samples are en route to the

laboratory, the field sampling personnel are taking new samples. 

Analysis Paths

When the laboratory receives the first set of samples, they begin by using the Scenario 1 flowchart.

By Day 2 1500 hours, results of radiochemical analyses indicate that 241Am is present together with

a lower amount of 238Pu. The samples have no detectable gamma emitters or radioiodines.

The laboratory calibrates its survey and GPC instruments with 241Amknowing that this is the primary

radionuclide. When the second batch of samples arrive at the laboratory, the chain-of-custody form

shows that the samples were taken at a flow rate of 20 cfm for 24 hours, for a total of 815 m3

. The

laboratory now knows that it will be using the Scenario 3 analytical flow on the next group of

samples. The second batch arrived at the laboratory on Day 2 at 1900 hours.

A survey meter with a thin window alpha probe calibrated using 241Am for gross alpha measurements

is used to make the measurements on the filters noted in the tables below. Also noted are the lab

measurements made when they arrived at the laboratory with similar instrumentation. The IC has

decided to establish the extent of the spread of the radioactive contamination and wants the lowest

activity samples analyzed first to the 5×10–6 risk AAL values.

NOTE: The values for the 1×10–6 risk values in Tables

8A and 8B must be multiplied by 5 to generate values

for 5×10-6 risk ADL. 

The IC also has been given evidence to support the presence of 238Pu as well as 241Am, but at lower

concentrations than the 241Am. The IC therefore wants 238Pu analysis performed as the laboratory’s

The number of samples have been minimized and the screening processes have been simplified in

this example. In an actual event, the number and complexity of samples will be much greater than

identified here.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

64

second priority. The ADL values for 241Am and 238Pu are 1.2×10–2 and 8.5×10–3, respectively.

Although the tables for 1×10–6 risk are based on radionuclide-specific methods, in this instance they

are used for screening purposes to help prioritize these samples, because an unknown component

(

238Pu) may be present.

Filter ID

Gross Alpha,

cpm (Field)

Gross Alpha,

cpm (Lab)

Gross Beta,

cpm (Field)

Gross Beta,

cpm (Lab)

A 682 610 1530 420

B 710 700 1510 415

C 715 720 1485 495

Background

air filter sample* 680 600 1505 420

*This represents the routine ambient sample count rate from samples taken at this location

prior to this event with similar delivery times to the laboratory.

Step 1. All Filters. The α path is chosen because the principal radionuclides specified by the IC for

analysis are both alpha emitters (although 241Am is a gamma emitter, gamma spectrometry would

require very long count times at the concentrations expected in the samples).

Step 2α. All Filters. Samples are to be screened using GPC analysis where the instrument is

calibrated with 241Am. It is Day 2 1930 hours.

Step 3α. All Filters. The laboratory analysis using GPC has determined that the sample with the

lowest activity is A. The B and C filters will be processed subsequent to the analysis of filter A. Day

3 0330 hours

Step 4α1. Filter A. Filter A is digested and then americium-specific separations are performed. The

value determined for 241Am based on alpha spectrometry is 5.5×10–5 pCi/m3. It is Day 3 0530 hours.

Step 5α. Filter A. The same aliquant of the digestate from the filter is used for determination of

plutonium by sequential separation steps when the 241Am was performed. Analysis for 238Pu is

performed using alpha spectrometry. The value determined is 1.2×10–5 pCi/m3

. It is Day 3 0700

hours.

 The scaled ADL values for 241Am and 238Pu at the 5×10!6 Step 6α. Filter A. risk ADL based on Table

8A are 1.2×10–2 and 8.5×10–3 pCi/m3, respectively. The scaled uMR values are 2.1×10–3 and 1.5×10–3

pCi/m3, respectively. (The 1×10–6 risk ADL values are multiplied by 5 to get the 5×10–6 risk ADL

values.)

 Both values are less than their respective ADL values (at 5×10–6 Step 7. Filter A. risk) and the final

concentrations agree with the initial gross alpha activity measurements (i.e., such a low activity would

not be detected at count rates higher than the background using screening equipment).

The sum of the fractions for 241Am and 238Pu (based on 10–4 Step 8. Filter A. AAL values from

Table 8A divided by 20) are:

Sum = (5.5×10–5 / 1.6×10–2) + (1.2×10–5 / 1.2×10–2)
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

65

= 0.0034 + 0.001

= 0.0044

This is less than 1.0.

Step 9. Filter A. Results are reported to the IC. Final analysis of Filters B and C is performed at the

direction of the IC. It is Day 3 0830 hours.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

66

Timeline (Hours)

0.0

1.0

2.5

4.5

5.0

10

16.5

20

22

26

30

Samples arrive at lab

Gamma spectrometry

completed

Rapid gross analyses completed for β/γ and α

Commence α-, β-, γ-specific 

analyses based on direction of 

Incident Commander

(follow Scenario 2 flow chart)

Sample digestion completed.

Aliquants taken.

90Sr analysis completed if 

necessary

Transuranics and 

other α analyses 

completed

Review all results and 

report to Incident 

Commander

Archive final 

sample forms

Sample does not

exceed any PAG 

concentration limit

Sample exceeds a 

PAG limit

Gross α/β completed

Other β-only emitters 

completed

90Sr recount

3H and radioiodine 

analyses completed

Figure 5 – Approximate Timeframe for Radiochemical Analyses (Radioanalytical

Scenario 1)

APPENDIX V. Representative Analytical Processing Times

The vertical position of the milestones depicted in the following three figures correspond to the

elapsed time on the timelines to the right or left. The timelines are approximate and assume the use

of rapid analytical separation methods (versus traditional methods) for environmental levels of the

analytes represented in this document.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

67

Timeline

(Hours)

>500 mrem

0.0

2.5

4.5

7.5

26

30

32

35

Samples arrive at lab

Rapid gross α-, β-, γ

lab scan completed

Commence α-, β-, γ-specific 

analyses for 10-4 and 10-6 risk AALs

Sample digestion completed;

separate aliquants removed

Specific α

analyses 

completed

Review all results and 

report to IC

Archive final 

sample forms

Gross α, β analyses 

by GPC 

completed

90Sr recount if 

necessary

Gamma analyses

(0.5 to 2 hours each) 

on filter completed

Routine gross α, β

analyses on filter and 

γ on charcoal 

completed 

90Sr and specific β-emitters 

analyses completed

Sample digestion 

completed

Routine γ analysis of filter

Timeline*

(Hours)

<500 mrem

0.0

10

14

24

36

50

60

*The <500-mrem timeline assumes that high priority samples are GPC-counted after digestion before any lower-priority samples.

Radionuclide-specific 

analyses completed Review all 

results and 

report to IC

Figure 6 – Approximate Timeframe for Radiochemical Analyses (Radioanalytical 

Scenario 2)
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

68

Review data from field and lab 

hand-held screening 

instruments

Samples arrive at laboratory

Gross α/β

screen by GPC

completed 

γ analysis 

for 10–6

risk level

γ analysis

screen

completed

Gross α/β

screen by GPC

completed

γ analysis 

for 10–4

risk level

α-specific 

commenced 

completed

β-specific 

commenced

completed

Counting

completed

α-specific

analysis

commenced

β-specific 

analysis

commenced

Final report 

to IC

Counting

completed

Final report 

to IC

Timeline 

with γ

(hours)

1.0

4.5

9.5

10.5

20.0

26.0

28.0

30.0

Archive final 

sample forms 

Timeline

without γ

(hours)

0.5

1.5

14.0

20.0

22.0

24.0

Figure 7 – Approximate Timeframe for Radiochemical Analyses (Radioanalytical 

Scenario 3)
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

69

TABLE 9 – Air Monitoring: Air Filter Counting Times for Various PAGs and Sampling Rates and

Durations

PAG/

RISK

Flow

Rate

(cfm)

Sampling

Duration

Volume

Collected

(m3

)

Counting

Instrument

Alpha Screening

Counting Time

(Minutes) for

Detectability†‡

Beta Screening

Counting Time

(Minutes) for

Detectability†

2 rem/y

40 1 h 68 GPC* ~1 <<<1

40 5 m 5.7 GPC ~20 <<<1

2 10 h 34 GPC ~2 <<<1

2 1 h 3.4 GPC <30 <<<1

2 10 m 0.57 GPC ~300 <<1

500

mrem/y

40 24 h 1631 GPC <1 <<<1

40 1 h 68 GPC ~4 <<<1

2 1 h 3.4 GPC <200 <<<1

2 8 h 27 GPC <10 <<1

10!4

 Risk

40 24 h 1631 GPC <1 <<<1

40 8 h 544 GPC <1 <<<1

2 24 h 82 GPC ~2 <<<1

2 7 d 571 GPC <1 <<<1

10!6

 Risk

40 24 h 1631 GPC/GPC ~10 <<<1

40 7 d 11,420 GPC/GPC ~2 <<<1

40 24 h 1631 α AS**/GPC ~10 <<<1

2 24 h 82 α AS**/GPC ~120 <<1

2 7 d 571 GPC/GPC ~40 <<1

2 7 d 571 α AS**/GPC ~20 <<1

† Counting time to have net count rate equal to 3 times the net count rate uncertainty. 

‡ Counting times presented for 239Pu. Counting times for the other alpha-emitting nuclides of interest are similar or

shorter except for 228Th and 210Po which are much longer.

* gas proportional counter: Alpha detection efficiency/background—10% / 0.05 cpm; beta detection efficiency/

background—30% / 1 cpm.

** Alpha spectrometry counting after radiochemistry processing assuming 100% yield; detector efficiency background—

22% / 0.005 cpm.

• To calculate counting times to reach a relative 10% net count rate uncertainty, multiple the counting times in the table

by 11.

• The “~” symbol is used for count times because the efficiency will vary slightly from detector to detector. The “<“

symbol indicates that the count times are less than the stated value regardless of the efficiency.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

70

FIGURE 8 – A Decision

Point in a Flowchart

APPENDIX VI. Establishing DQOs and MQOs for Incident Response Analysis

Three distinct radioanalytical scenarios are presented for air particulate filters potentially

contaminated with radionuclides. The first two assume that the mixture of radionuclides in the sample

is unknown. The third situation, a shortened version of the first two, assumes that the radioactive

contaminants are known. In each scenario there is special emphasis on the implementation of the

decision trees presented within that scenario for prioritizing sample processing by the laboratory. This

emphasis on the decision trees is to support timely decision making by the IC regarding actions to

protect human health for the first two cases, and in the third case, to expedite analysis so that areas

suitable for reoccupation may be identified. Specific MQOs associated with the flow diagrams in

Figures 2, 3, and 4 are given in Tables 11, 12, and 13.

This appendix covers single-sample screening measurement decisions by the laboratory. The IC may

need to make decisions based on the final radionuclide-specific concentrations based on the mean of

the set of samples taken from an area. Measurement quality objectives (MQOs) would need to be

developed separately for this case. The required method uncertainty (uMR) should be smaller in this

case compared to the laboratory’s screening decisions, perhaps by a factor of three (see MARLAP

Appendix C).

The flowcharts depicted in this document contain decision points.

There are three basic symbols on these flowcharts: rectangles, which

represent activities or tasks; decision point diamonds, which represent

decision points; and arrows, which represent flow of control. In these

flow diagrams, there are many diamond-shaped decision points. Most

often they are of the form shown in Figure 8. This is the general form

of a theoretical decision rule as discussed in Step 5 of the data quality

objectives (DQO) process. The parameter of interest usually is the

“measurand” of the radiochemical analysis being performed (e.g.,

concentration of a radionuclide, total activity, etc.). The AALs will have been set according to criteria

involving the appropriate PAGs. The arrows specify the alternative actions to be taken.

The DQO process may be applied to all programs involving the collection of environmental data with

objectives that cover decision making activities. When the goal of the study is to support decision -

making, the DQO process applies systematic planning and statistical hypothesis testing methodology

to decide between alternatives. Data quality objectives can be developed using the Guidance in EPA

(2006) Guidance on Systematic Planning Using the Data Quality Objectives Process (EPA QA/G-4).

The DQO process is summarized in Figure 9.

Table 10A summarizes the DQO process. From this, MQOs can be established using the guidance

in MARLAP. The information in this table should be sufficient to enable the decision maker and

laboratory to determine the appropriate MQOs. The output should include an AAL, discrimination

limit, gray region, null hypothesis, analytical decision level (ADL, referred to in MARLAP as “critical

level”), and required method uncertainty at the AAL. A table summarizing DQO process for each

decision point diamond can be prepared in advance and summarized as shown in Tables 11A and

11B.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

71

Figure 9 – The Data Quality Objectives Process
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

72

TABLE 10A – The DQO Process Applied to a Decision Point

STEP OUTPUT

Step 1. Define the problem ... with a preliminary determination of the type of data needed and how

it will be used; identify decision maker.

Step 2. Identify the decision ...among alternative outcomes or actions, and a list of decision

statements that address the problem.

Step 3. Identify information

needed for the

decision

Analytical action levels that will resolve the decision and potential

sources for these; information on the number of variables that will need

to be collected; the type of information needed to meet performance or

acceptance criteria; information on the performance of appropriate

sampling and analysis methods. 

Step 4. Define the boundaries

of the study

Definition of the target population with detailed descriptions of

geographic limits (spatial boundaries); detailed descriptions of what

constitutes a sampling unit timeframe appropriate for collecting data and

making the decision or estimate, together with any practical constraints

that may interfere with data collection; and the appropriate scale for

decision making or estimation. 

Step 5. Develop a decision rule

This defines the decision point

diamond. 

Identification of the population parameters most relevant for making

inferences and conclusions on the target population; for decision

problems, the “if..., then...else...” theoretical decision rule based upon a

chosen AAL. 

The theoretical decision rule specified in Step 5 can be transformed into statistical hypothesis tests

that are applied to the data. Due to the inherent uncertainty with measurement data, there is some

likelihood that the outcome of statistical hypothesis tests will lead to an erroneous conclusion, i.e.,

a decision error. This is illustrated in Table 10B.

TABLE 10B – Possible Decision Errors

Decision Made

True Value of the parameter of interest

Greater than the action level Less than the action level

Decide that the parameter of interest is

greater than the action level Correct decision Decision Error

Decide that the parameter of interest is

less than the action level Decision Error Correct decision

In order to choose an appropriate null hypothesis (or baseline condition), consider which decision

error should be more protected against. Choose the null hypothesis which if falsely rejected would

cause the greatest harm. Then the data will need to be convincingly inconsistent with the null

hypothesis before it will be rejected, and the probability of this happening (a Type I error) is more

easily controlled during the statistical design.

Failing to detect a sample that exceeds the AAL could have consequences to public health. But

screening additional samples will slow the overall process and therefore also may impact the public

health. The probability that such decision errors occur is defined as the parameters α and β in Steps

6.1 and 6.2 in Table 10C. Values of alpha and beta should be set based on the consequences of
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

73

making an incorrect decision. How these are balanced will depend on the AAL, sample loads, and

other factors as specified by the IC.

The most commonly used values of alpha and beta are 5%, although this is by tradition and has no

sound technical basis. These values may be used as a default, but should be optimized in Step 7 of

the DQO process according to the actual risk of the decision error being considered.

TABLE 10C – The DQO Process Applied to a Decision Point

STEP OUTPUT

Step 6. Specify limits on

decision errors

Step 6.1 Determine analytical action level (AAL) on

the gray region boundary

and set baseline condition

(null hypothesis, H0)

Which is considered the worse: decision error (a) deciding that the parameter of

interest is less than the AAL when it actually is greater, or (b) deciding that the

parameter of interest is greater than the AAL when it actually is less? Case (a) is

usually considered to be a conservative choice by regulatory authorities, but this

may not be appropriate in every case.

If (a), the AAL defines the upper boundary of the gray region. The null hypothesis

is that the sample concentration is above the AAL. (All samples will be assumed

to be above the AAL unless the data are convincingly lower.) A desired limit will

be set on the probability (α) of incorrectly deciding the sample is below the AAL

when the sample concentration is actually equal to the AAL.

If (b), the AAL defines the lower boundary of the gray region. The null hypothesis

is that the sample concentration is below the AAL. (All samples will be assumed

to be below the AAL unless the data are convincingly higher.) A desired limit will

be set on the probability (α) of incorrectly deciding the sample is above the AAL

when the sample concentration is actually equal to the AAL.

6.2 Define the discrimination limit (DL)If (a), the discrimination limit defines the lower boundary of the gray region.1

 It

will be a concentration below the AAL where the desired limit will be set on the

probability (β) of incorrectly deciding the sample is above the AAL.

If (b), the discrimination limit defines the upper boundary of the gray region.2

 It

will be a concentration above the AAL where the desired limit will be set on the

probability (β) of incorrectly deciding the sample is below the AAL.

6.3 Define the required

method uncertainty at the

AAL

According to MARLAP Appendix C, under either case (a) or case (b) above, the

recommended required method uncertainty is:

u

UBGR LBGR

zz zz

MR ≤ −

+ =

11 11 −− −− αβ αβ +

Δ

where z1–α and z1–β are the 1–α and 1–β quantiles of the standard normal

distribution function.

Step 7. Optimize the design

for obtaining data

Iterate Steps 1–6 to define optimal values for each of the parameters and the

measurement method required. 

NOTES: 1

 The DL is the point where it is important to be able to distinguish expected signal from the AAL. When one expects background

activity, then it might be zero. If one expects activity near the AAL, however, it might be at 90% of the AAL.

2

 The DL is the point where it is important to be able to distinguish expected signal from the AAL. If the AAL is near zero, the DL

would define a concentration deemed to be too high to be undetected. Thus, the DL may be set equal to the MDC. If one expects

activity near the AAL, however, it might be at 110% of the AAL.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

74

Figures 10 and 11 illustrate the concepts above for case (a) and case (b) respectively.

In Figure 10, the AAL = 100, the DL = 80, Δ = 100 – 80 = 20 α = β = 0.1 and

u . z z

MR ≤

+ = + =

− −

Δ

1 1

20

1282 1282

7 8

α β . . .

In Figure 11, the AAL = 100, the DL = 120, Δ = 120-100 = 20 α = β = 0.1 and

u . z z

MR ≤

+ = + =

− −

Δ

1 1

20

1282 1282

7 8

α β . . .

Table 10D – Values of z1-α (or z1–β) for

Some Commonly Used Values of α (or β)

α or β z1-α (or z1–β)

0.001 3.090

0.01 2.326

0.025 1.960

0.05 1.645

0.10 1.282

0.20 0.842

0.30 0.524

0.50 0.000

Figure 10 – Example Illustrating Case (a).

Baseline Condition (null hypothesis): Parameter

Exceeds the Analytical Action Level

Figure 11 – Example Illustrating Case (b).

Baseline Condition (null hypothesis): Parameter

Does Not Exceed the Analytical Action Level

Figures taken from EPA G-4 (2006)
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

21 In this appendix, we use the term critical value to be consistent with MARLAP terminology. It should be noted that

the critical value in the context of this document refers to the ADL value.

75

The concentration that indicates the division between values leading to rejecting the null hypothesis

and those that do not is termed the “critical level.” Possible values of the concentration can be divided

into two regions, the acceptance region and the rejection region. If the value of the concentration

comes out to be in the acceptance region, the null hypothesis being tested is not rejected. If the

concentration falls in the rejection region, the null hypothesis is rejected. The set of values of a

statistic that will lead to the rejection of the null hypothesis tested is called the critical region. Critical

region is a synonym for rejection region.

In the context of analyte detection, the critical value (see MARLAP Attachment 3B.221) is the

minimum measured value (e.g., of the instrument signal or the analyte concentration) required to give

confidence that a positive (nonzero) amount of analyte is present in the material being analyzed. The

critical value is sometimes called the critical level.

In case (a), the critical value will be UBGR – z1–α uM, where uM is its combined standard uncertainty

of the measurement result, x. Only measurement results less than the critical value will result in

rejecting the null hypothesis that the true concentration is greater than the AAL. This process can be

completed for each diamond in each flowchart to fill in Tables 11A, 11B, 12A, 12B, and 13. In these

tables, values have been rounded to 2 or 3 significant figures.

In case (b), the critical value will be LBGR + z1–α uM, where uM is its combined standard uncertainty

of the measurement result, x. Only measurement results greater than the critical value will result in

rejecting the null hypothesis that the true concentration is less than the AAL.

In the following tables, MQOs were determined for screening using a discrimination level of zero and

Type I and Type II error rates of α = β = 0.05. These are the MQOs usually associated with developing

MDCs and result in a relative method uncertainty of 30% at the AAL, and an ADL value of 0.5 times

the AAL.

For radionuclide-specific measurements the requirements are more stringent, using a discrimination

level of one-half the AAL and Type I and Type II error rates of α = 0.01 with β = 0.05. This results

in a relative required method uncertainty of 13% at the AAL and an ADL value of 0.71 times the

AAL.

Note that gamma spectrometric measurements using an HPGe are always radionuclide-specific, and

therefore have the more stringent MQOs
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

76

TABLE 11A – DQOs and MQOs for Radioanalytical Scenario 1. Laboratory Prioritization Decisions

Based on Screening (Gross α, β, or γ Measurements), Tritium and Iodines[1]

Measurement RectangleDecision Point DiamondType of Analysis, α, β, or γ

Analytical AL (pCi/m3

)

Null Hypothesis H0

Choose > AAL or <AALi.e., case (a) or case (b)DLDL < AAL in case (a) andDL > AAL in case (b)Δ = UBGR-LBGR

Type I error rate αType II error rate 

β

uMRnMRAnalytical Decision Level(Critical Level) (pCi/L)Source of AAL 

1 1a α 0.7 a 0 0.7 0.05 0.05 0.21 0.30 0.35 2-rem α screening

AAL 

1 1a β/γ 420 a 0 420 0.05 0.05 130 0.30 210 2-rem β screening

AAL 

1b 3b 3H 2.6×105 a 0 2.6×105 0.05 0.05 7.8×104 0.30 1.3×105 2-rem 3H AAL 

1c 3b 125I 1.3×104 a 0 1.3×104 0.05 0.05 3.9×103 0.30 6.5×103 2-rem 125I AAL 

1c 3b 129I 1.9×103 a 0 1.9×103 0.05 0.05 570 0.30 950 2-rem 129I AAL 

1c 3b 131I 9.1×103 a 0 9.1×103 0.05 0.05 2.7×103 0.30 4.6×103 2-rem 131I AAL 

2 3a α 0.7 a 0 0.7 0.05 0.05 0.21 0.30 0.35 2-rem α screening

AAL 

2 3a β/γ 420 a 0 420 0.05 0.05 130 0.30 210 2-rem β screening

AAL 

2 3a γ see Table

12B

a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL 2-rem AAL 

from Table 7B

2 3a 125I 1.3×104 a 0 1.3×104 0.05 0.05 3.9×103 0.30 6.5×103 2-rem 125I AAL 

2 3a 129I 1.9×103 a 0 1.9×103 0.05 0.05 570 0.30 950 2-rem 129I AAL 

2 3a 131I 9.1×103 a 0 9.1×103 0.05 0.05 2.7×103 0.30 4.6×103 2 rem 131I AAL 

6 [2]

13 14 γ see Table

12B

a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL 500-mrem AAL 

from Table 7C

13 14 α 0.17 a 0 0.17 0.05 0.05 0.051 0.30 0.085 500-mrem α

screening AAL 

13 14 β 110 a 0 110 0.05 0.05 33 0.30 55 500-mrem β

screening AAL 

Notes:

[1] Rounded to two significant figures.

[2] Mathematically computed from data obtained earlier in measurement rectangles 2 and 5.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

77

TABLE 11B – DQOs and MQOs for Scenario 1. Values Reported to the Incident Commander Based

on Radionuclide-Specific Measurements

Measurement RectangleDecision Point Diamond Type of Analysis, α, β, or γ

Analytical AL (pCi/m3

)

Null Hypothesis H0

Choose > AAL or < AALi.e. case (a) or case (b)DLDL < AAL in case (a) andDL > AAL in case (b)Δ = UBGR-LBGR

Type I error rate αType II error rate

β

uMRnMRAnalytical Decision Level(Critical Level) (pCi/L)Source of AAL [2]

9 11 α

See Tables 11A and 11B

a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL[1] 2 rem AAL 

7,8 11 β a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL 2 rem AAL 

10 11 γ a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL 2 rem AAL 

9 11 α a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL 500 mrem AAL 

7,8 11 β a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL 500 mrem AAL 

10 11 γ a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL 500 mrem AAL 

Notes:

[1] In case (a), the critical value is UBGR – z1–α uM = AAL – z1–0.01 [Δ/(z1–0.01 + z1–0.05) ] 

= AAL – 2.326 [ (AAL–0.5 AAL)/(2.326 + 1.645) ]

= AAL – 2.326 (0.13×AAL) . 0.71 × AAL. 

Specific values for the ADL are listed in Tables 7C and 7D.

[2] When following a green pathway in the flow diagram for Scenario 1, use the 500-mrem AAL MQOs.

When following a red pathway in the flow diagram for Scenario 1, use the 2-rem AAL MQOs. 
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

78

TABLE 12A – DQOs and MQOs for Radioanalytical Scenario 2. Laboratory Prioritization Decisions

Based on Screening (Gross α, β, or γ Measurements) and 131I

Measurement RectangleDecision Point DiamondType of Analysis, α, β, or γ

Analytical AL (pCi/m3

)

Null Hypothesis H0

Choose > AAL or <AALi.e., case (a) or case (b)DLDL < AAL in case (a) andDL > AAL in case (b)Δ = UBGR-LBGR

Type I error rate αType II error rate 

β

uMRnMRAnalytical Decision Level(Critical Level) (pCi/m3

)

Source of AAL 

1,5 2,6 α 0.17 a 0 0.17 0.05 0.05 0.051 0.30 0.085 500-mrem α

screening AAL

Table 7A

1,5 2,6 β/γ 110 a 0 110 0.05 0.05 33 0.30 55 500-mrem β

screening AAL

Table 7B

3 6 γ

see

Table

12B

a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71

×AAL

500-mrem AAL 

from Table 7B

7,8,21 10 [1]

15,16,

17

18,19,

20 [2]

11 12 α 0.33 a 0 0.33 0.05 0.05 0.099 0.30 0.16 10-4 risk α

screening AAL

from Table 8A 

11 12 β 29 a 0 29 0.05 0.05 8.7 0.30 14 10-4 risk β AAL

from Table 8B 

Notes:

All numbers rounded to two significant figures.

[1] Mathematically computed from data obtained earlier in measurement rectangles 2 and 5.

[2] Mathematically computed from data obtained earlier in measurement rectangles 2, 7, and 8.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

79

TABLE 12B – DQOs and MQOs for Scenario 2. Values Reported to the Incident Commander Based

on Radionuclide-Specific Measurements

Measurement RectangleDecision Point Diamond Type of Analysis, α, β, or γ

Analytical AL (pCi/m3

)

Null Hypothesis H0

Choose > AAL or < AALi.e. case (a) or case (b)DLDL < AAL in case (a) andDL > AAL in case (b)Δ = UBGR-LBGR

Type I error rate αType II error rate 

β

uMRnMRAnalytical Decision Level(Critical Level) (pCi/m3

)

Source of AAL [2]

11 12 131I 640 a 320 320 0.01 0.05 42 0.13 570 10-4 risk 131I AAL 

11 12 γ

see Table 8B

a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL 10-4 risk AAL

from Table 8B

15 18,19 α

See Tables 8A and 8B

a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL [1] 10–4 risk AAL 

16 18,19 β a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL 10–4 risk AAL 

13, 17 18,19 γ a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL 10–4 risk AAL 

15 18,19 α a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL 10–6 risk AAL 

16 18,19 β a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL 10–6 risk AAL 

13, 17 18,19 γ a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL 10–6 risk AAL 

13,

15,16,

17

20 [3] These are regulatory derived values.

Notes:

[1] In case (a), the critical value is UBGR – z1--α uM = AAL – z1–0.01 [Δ/(z1–0.01 + z1–0.05) ] 

= AAL – 2.326 [ (AAL–0.5 AAL)/(2.326 + 1.645) ]

= AAL – 2.326 (0.13×AAL) . 0.71 × AAL. 

Specific values for the ADL are listed in Tables 8a and 8B.

[2] When following a green pathway in the flow diagram for Scenario 2, use the 500-mrem MQOs. When

following a yellow pathway in the flow diagram for Scenario 2, use the 10–4 risk MQOs. 

[3] Mathematically computed from data obtained earlier.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

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TABLE 13 – DQOs and MQOs for Scenario 3. Values Reported to the Incident Commander Based

on Radionuclide-Specific Measurements.

Measurement RectangleDecision Point Diamond Type of Analysis, α, β, or γAnalytical AL (pCi/m3

)

Null Hypothesis H0

Choose > AAL or < AALi.e. case (a) or case (b)DLDL < AAL in case (a) andDL > AAL in case (b)Δ = UBGR-LBGRType I error rate αType II error rate 

β

uMRnMRAnalytical Decision Level(Critical Level) (pCi/m3

)

Source of AAL

2μ 3μ α,β, γ

See Tables 8A and 8B

a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL 10–4 risk AAL from

Table 8A or8 B 

2α 3α α a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL

10–4 risk α

screening AAL

from Table 8A 

2β 3β β a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL

10–4 risk screening

β AAL from Table

8B 

4α 4α2 α a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL [1] 10–4 risk AAL 

4β 4β2 β a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL 10–4 risk AAL 

4μ 4μ2 α,β, γ a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL 10–4 risk AAL 

4α 4α1 α a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL 10–6 risk AAL 

4β 4β1 β a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL 10–6 risk AAL 

4μ 4μ1 α,β, γ a 0.5AAL 0.5AAL 0.01 0.05 0.13×AAL 0.13 0.71×AAL 10–6 risk AAL 

5μ, 6μ 7,8 [2]

5α, 6α 7,8 [2]

5β, 6β 7,8 [2]

Notes:

[1] In case (a), the critical value is UBGR – z1--α uMR = AAL – z1–0.01 [Δ/(z1–0.01 + z1–0.05) ] 

= AAL – 2.326 [ (AAL–0.5 AAL)/(2.326 + 1.645) ]

= AAL – 2.326 (0.13×AAL) . 0.71 AAL. 

Radionuclide-specific ADL values are listed in Table 8.

[2] Mathematically computed from data obtained earlier in measurement rectangles 4 and 5. 

Estimated counting times for a filter sample on a gas proportional counter to reach an alpha detection limit

and a 10% count rate uncertainty for low- and high-volume air samples at 500-mrem derived air

concentrations are given in Table 16.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance – Radionuclides in Air

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Radionuclide

500-mrem AAL

(pCi/m3

)

Low Volume (3.4 m3

)

[1]

High Volume (1,631 m3

)

[1]

Filter

Activity

(pCi)

Counting

Time for

Detection

Limit (min)

[2] [3]

Counting Time for

10% Uncertainty

(min)

[2]

Filter

Activity

(pCi)

Counting Time

for Detection

Limit (min)

[2] [3]

Counting Time for

10% Uncertainty

(min)

[2]

Am-241 0.17 0.58 120 1400 280 <1 ~2Cm-242 2.8 9.5 4.5 50 4,600 <1 ~1Cm-243 0.24 0.82 77 860 390 <1 ~1Cm-244 0.29 0.99 60 670 470 <1 ~1

Np-237 0.34 1.2 49 540 560 <1 ~1

Po-210 3.9 13 3 35 6,400 <1 <1

Pu-238 0.15 0.51 150 1700 240 <1 ~2Pu-239 0.14 0.48 170 1800 230 <1 ~2Pu-240 0.14 0.48 170 1800 230 <1 ~2

Ra-226 1.8 6.1 7 w/o DP 79 w/o DP 2,900 <1 <1

Th-228 0.42 1.4 37 420 690 <1 ~1Th-230 0.17 0.58 120 1400 280 <1 ~2Th-232 0.15 0.51 150 1700 240 <1 ~2

U-234 1.8 6.1 7 79 2,900 <1 <1U-235 2.0 6.8 6 71 3,300 <1 <1U-238 2.1 7.1 6 67 3,400 <1 <1

Note: Values in table have been rounded.[1] Low volume= 2 ft3/minute for 60 minutes; total volume 3.4 m3. High volume= 40 ft3/minute for 24 hours; total volume 1,631 m3. 

[2] Assume the typical GPC detector efficiency and background count rate and alpha branching ratio of 1.

T

[3] Detection limit for this example is 3 times uncertainty = net count rate. 

ABLE 14 – Estimated Counting Times for a Filter Sample Analyzed on a Gas Proportional Counter To Reach an Alpha Detection Limit

and a 10% Count Rate Uncertainty for Low- and High-Volume Air Samples at 500-mrem AAL Values
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82

APPENDIX VII. Glossary

accuracy: The closeness of a measured result to the true value of the quantity being measured.

Various recognized authorities have given the word “accuracy” different technical definitions,

expressed in terms of bias and imprecision. Following MARLAP, this document avoids all of

these technical definitions and uses the term “accuracy” in its common, ordinary sense.

aerosol: A suspension of fine solid or liquid particles within a gaseous matrix (usually air).

aliquant: A representative portion of a homogeneous sample removed for the purpose of analysis or

other chemical treatment. The quantity removed is not an evenly divisible part of the whole

sample. An aliquot, by contrast, is an evenly divisible part of the whole.

analyte: See target analyte.

analytical action level (AAL): The value of a quantity that will cause the decision maker to choose

one of the alternative actions. The analytical action level may be a derived concentration level

(such as the derived air concentration in this document), background level, release criteria,

regulatory decision limit, etc. The AAL is often associated with the type of media, target analyte,

and concentration limit. Some AALs, such as the release criteria for license termination, are

expressed in terms of dose or risk. MARLAP uses the term “action level.” See total effective dose

equivalent (TEDE) and derived air concentration (DAC).

analytical decision level (ADL): The minimum measured value for the radionuclide concentration

in a sample that indicates the amount of radionuclide present is equal to or greater than the

analytical action level at a specified Type II error rate (assumes that method uncertainty

requirements have been met). Any measurement result equal to or greater than the applicable

ADL is considered to have exceeded the corresponding analytical action level. MARLAP uses

the term “critical level.”

background (instrument): Radiation detected by an instrument when no source is present. The background radiation that is detected may come from radionuclides in the materials of construction

of the detector, its housing, its electronics, and the building, as well as the environment and

natural radiation.

background level: A term that usually refers to the presence of radioactivity or radiation in the

environment. From an analytical perspective, the presence of background radioactivity in samples

needs to be considered when clarifying the radioanalytical aspects of the decision or study

question. Many radionuclides are present in measurable quantities in the environment.

bias (of a measurement process): A persistent deviation of the mean measured result from the true

or accepted reference value of the quantity being measured, which does not vary if a measurement

is repeated.
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blank (analytical or method): A sample that is assumed to be essentially free of the target analyte

(the “unknown”), which is carried through the radiochemical preparation, analysis, mounting, and

measurement process in the same manner as a routine sample of a given matrix.

calibration: The set of operations that establishes, under specified conditions, the relationship

between values indicated by a measuring instrument or measuring system, or values represented

by a material measure, and the corresponding known value of a parameter of interest.

calibration source: A prepared source, made from a certified reference material, that is used for

calibrating instruments.

certified reference material: A radioactive material, accompanied by an uncertainty at a stated level

of confidence, with one or more values certified by a procedure that establishes its traceability to

accepted standard values. A “standard reference material” is a certified reference material issued

by the National Institute of Standards and Technology (NIST) in the United States. NIST certifies

a standard reference material for specific chemical or physical properties and issues it with a

certificate that reports the results of the characterization and indicates the intended use of the

material.

chain of custody: Procedures that provide the means to trace the possession and handling of a sample

from collection to data reporting.

check source: A material used to validate the operability of a radiation measurement device,

sometimes used for instrument quality control. See source, radioactive.

critical level: Termed analytical decision level in this document in the context of evaluating sample

results relative to an analytical action level. In the context of analyte detection, critical level

means the minimum measured value (e.g., of the instrument signal or the radionuclide concentration) that indicates a positive (nonzero) amount of a radionuclide is present in the material within

a specified probable error. The critical level is sometimes called the critical value or decision

level.

data quality objective (DQO): Qualitative and quantitative statements that clarify the study

objectives, define the most appropriate type of data to collect, determine the most appropriate

conditions from which to collect the data, and specify tolerable limits on decision error rates.

Because DQOs will be used to establish the quality and quantity of data needed to support

decisions, they should encompass the total uncertainty resulting from all data collection activities,

including analytical and sampling activities.

derived air concentration (DAC): The concentration of a radionuclide, in pCi/m3, that would result

in exposure to a specified dose level. Generally refers to a protective action guide or other

specified dose- or risk-based factor expressed in equivalent radionuclide concentration and

referred to in this document as an analytical action level. Thus, the “500-mrem AAL for 239Pu”

is the derived air concentration of 239Pu, in pCi/m3

, that would result in an exposure of 500 mrem

and would refer to the 500-mrem PAG. The DAC is radionuclide-specific
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derived radionuclide concentration (DRC): General application term used in discussions involving

both of the terms derived air concentration and derived water concentration.

discrimination limit (DL): The DL is the point where it is important to be able to distinguish

expected signal from the analytical action level. The DL limit is one of the boundaries of the gray

region.

dose equivalent: Quantity that expresses all radiations on a common scale for calculating the effective

absorbed dose. This quantity is the product of absorbed dose (grays [Gy] or rads) multiplied by

a quality factor and any other modifying factors (MARSSIM, 2000). The quality factor adjusts

the absorbed dose because not all types of ionizing radiation create the same effect on human

tissue. For example, a dose equivalent of one sievert (Sv) requires 1 Gy of beta or gamma

radiation, but only 0.05 Gy of alpha radiation or 0.1 Gy of neutron radiation. Because the sievert

is a large unit, radiation doses often are expressed in millisieverts (mSv). See total effective dose

equivalent and roentgen.

gray (Gy): The International System of Units (SI) unit for absorbed radiation dose. One gray is 1 joule

of energy absorbed per kilogram of matter, equal to 100 rad. See sievert.

gray region: The range of possible values in which the consequences of decision errors are relatively

minor. Specifying a gray region is necessary because variability in the analyte in a population and

imprecision in the measurement system combine to produce variability in the data such that the

decision may be “too close to call” when the true value is very near the analytical action level.

The gray region establishes the minimum distance from the analytical action level where it is

most important to control Type II decision errors.

incident of national significance (INS): An actual or potential high-impact event that requires a

coordinated and effective response by an appropriate combination of federal, state, local, tribal,

nongovernmental, or private-sector entities in order to save lives and minimize damage, and

provide the basis for long-term community recovery and mitigation activities.

measurement quality objective (MQO): The analytical data requirements of the data quality

objectives, which are project- or program-specific and can be quantitative or qualitative. These

analytical data requirements serve as measurement performance criteria or objectives of the

analytical process. MARLAP refers to these performance objectives as MQOs. Examples of

quantitative MQOs include statements of required analyte detectability and the uncertainty of the

analytical protocol at a specified radionuclide concentration, such as the analytical action level.

Examples of qualitative MQOs include statements of the required specificity of the analytical

protocol (e.g., the ability to analyze for the radionuclide of interest [or target analyte] given the

presence of interferences).

method uncertainty: The predicted uncertainty of the result that would be measured if the method

were applied to a hypothetical laboratory sample with a specified analyte concentration. Although

individual measurement uncertainties will vary from one measured result to another, the required

method uncertainty is a target value for the individual measurement uncertainties and is an
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estimate of uncertainty before the sample is actually measured. See also uncertainty, required

method uncertainty, and required relative method uncertainty.

method validation: The demonstration that the method selected for the analysis of a particular analyte

in a given matrix is capable of providing analytical results to meet the project’s measurement

quality objectives and any other requirements in the analytical protocol specifications.

minimum detectable concentration (MDC): An estimate of the smallest true value of the analyte

concentration that gives a specified high probability of detection.

nuclide-specific analysis: Radiochemical analysis performed to isolate and measure a specific

radionuclide.

null hypothesis (H0): One of two mutually exclusive statements tested in a statistical hypothesis test

(compare with alternative hypothesis). The null hypothesis is presumed to be true unless the test

provides sufficient evidence to the contrary, in which case the null hypothesis is rejected and the

alternative hypothesis (H1) is accepted.

performance evaluation (PE) program: A laboratory’s participation in an internal or external

program of analyzing proficiency-testing samples appropriate for the analytes and matrices under

consideration (i.e., PE program traceable to a national standards body, such as NIST). Referencematerial samples used to evaluate the performance of the laboratory are called performanceevaluation or proficiency-testing samples or materials. See certified reference material.

precision: The closeness of agreement between independent test results obtained by applying the

experimental procedure under stipulated conditions. Precision may be expressed as the standard

deviation. Conversely, imprecision is the variation of the results in a set of replicate

measurements.

protective action guide (PAG): The radiation dose to individuals in the general population that

warrants protective action following a radiological event. In this document, PAGs limit the

projected radiation doses for different exposure periods: not to exceed 2-rem total effective dose

equivalent (TEDE) during the first year, 500-mrem TEDE during the second year, or 5 rem over

the next 50 years (including the first and second years of the incident). See total derived water

concentration and analytical action level.

quality assurance (QA): An integrated system of management activities involving planning,

implementation, assessment, reporting, and quality improvement to ensure that a process, item,

or service is of the type and quality needed and expected. Quality assurance includes quality

control.

quality control (QC): The overall system of technical activities that measures the attributes and

performance of a process, item, or service against defined standards to verify that they meet the

stated requirements established by the project; operational techniques and activities that are used

to fulfill requirements for quality. This system of activities and checks is used to ensure that
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measurement systems are maintained within prescribed limits, providing protection against outof-control conditions and ensuring that the results are of acceptable quality.

reference material: See certified reference material.

rem: The common unit for the effective or equivalent dose of radiation received by a living organism,

equal to the actual dose (in rads) multiplied by a factor representing the danger of the radiation.

Rem is an abbreviation for “roentgen equivalent man,” meaning that it measures the biological

effects of ionizing radiation in humans. One rem is equal to 0.01 Sv. See sievert and dose

equivalent.

required method uncertainty (uMR): Method uncertainty at a specified concentration. A key

measurement quality objective. See also required relative method uncertainty.

required relative method uncertainty (nMR): The required method uncertainty divided by the

analytical action level. The required relative method uncertainty is applied to radionuclide

concentrations above the analytical action level. A key measurement quality objective.

roentgen (R): A unit of exposure to ionizing radiation. It is that amount of gamma rays or X-rays

required to produce ions carrying one electrostatic unit of electrical charge in one cubic centimeter

of dry air under standard conditions. The unit of exposure rate is roentgens per hour (R/h). For

environmental exposures, the typical units are microroentgens per hour (μR/h), or 10–6 R/h. In SI

units, 1 R = 2.58×10–4 C/kg (coulombs per kilogram).

sample: (1) A portion of material selected from a larger quantity of material. (2) A set of individual

samples or measurements drawn from a population whose properties are studied to gain information about the entire population.

sample test source: The product of a chemical or physical process prepared for the purpose of activity

determination (ASTM D7282). Also considered to be the final form in a geometry that will be

counted by a radiation detector.

screening method: An economical gross measurement (alpha, beta, gamma) used in a tiered approach

to method selection that can be applied to analyte concentrations below an analyte level in the

analytical protocol specifications or below a fraction of the specified action level.

sievert (Sv): The SI unit for the effective dose of radiation received by a living organism. It is the

actual dose received (grays in SI or rads in traditional units) times a factor that is larger for more

dangerous forms of radiation. One Sv is 100 rem. Radiation doses are often measured in mSv. An

effective dose of 1 Sv requires 1 gray of beta or gamma radiation, but only 0.05 Gy of alpha

radiation or 0.1 Gy of neutron radiation.

source, radioactive: A quantity of material configured for radiation measurement.
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source term radionuclide: A radionuclide that is a significant contaminant in an environmental

sample and results in dose contributions that will be important in decisionmaking.

sum of the fractions: A calculated value to determine whether the summed contributions to dose by

all radionuclides in a sample, divided by their respective dose limits, exceeds 1.0. For purposes

of this calculation, the actual analytical action level (derived air concentration or protective

action guide) is used rather than an analytical decision level.

swipe: A filter pad used to determine the level of general radioactive contamination when it is wiped

over a specific area, about 100 cm2 in area. Also called smears or wipes.

target analyte: A radionuclide on the list of radionuclides of interest or a radionuclide of concern for

a project.

total effective dose equivalent: The sum of the effective dose equivalent (for external exposure) and

the committed effective dose equivalent (for internal exposure), expressed in units of Sv or rem.

See dose equivalent.

Type I decision error: In a hypothesis test, the error made by rejecting the null hypothesis when it is

true. A Type I decision error is sometimes called a “false rejection” or a “false positive.”

Type II decision error: In a hypothesis test, the error made by failing to reject the null hypothesis

when it is false. A Type II decision error is sometimes called a “false acceptance” or a “false

negative.”

uncertainty: A parameter, associated with the result of a measurement, that characterizes the

dispersion of the values that could reasonably be attributed to the measurand. See method

uncertainty.