Radiological Laboratory Sample 

Analysis Guide for Incidents 

of National Significance –

Radionuclides in Water

Office of Radiation and Indoor Air 

National Air and Radiation

Environmental Laboratory

United States

Environmental Protection

Agency

EPA 402-R-07-007

January 2008

www.epa.gov/narel
 
EPA 402-R-07-007

www.epa.gov

January 2008

Revision 0

Radiological Laboratory

Sample Analysis Guide for

Incidents of National Significance — 

Radionuclides in Water

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

Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

i

Preface

The document describes the likely analytical decision paths that would be required 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 Plan Nuclear/

Radiological Incident Annex, 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 an INS has been recognized by a number of federal agencies. The Integrated Consortium

of Laboratory Networks (ICLN), created through a memorandum of understanding in 2005 by ten

federal agencies, consists of existing and emerging laboratory networks across the Federal

Government. 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 and drinking water samples, EPA is

developing the Environmental Laboratory Response Network (eLRN). As an RFA for radiological

agents, eLRN will be responsible for monitoring, surveillance, and remediation, and will share

responsibility for incident response with the Department of Energy. As part of eLRN, EPA’s Office

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

radioanalytical capability and competency exists across a core set of laboratories to carry out EPA’s

designated RFA responsibilities.

Three radioanalytical scenarios, responding to two different public health questions, address the

immediate need to determine the concentration of known or unknown radionuclides in water. The

scenarios are based upon the radionuclides that probably would be released by a radiological

dispersion device or those that may be released intentionally into the drinking water supply. The first

analytical scenario assesses whether water samples pose immediate threats to human health and

warrant implementation of protective measures specific to radiation concerns. The second assesses

whether specific water sources (samples) are potable based on current national drinking water

standards. 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.

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
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

ii

Standardized Analytical Methods for Environmental Restoration following Homeland Security

Events, Revision 3 (EPA 600-R-07-015).

Detailed guidance on recommended radioanalytical practices may be found in current editions of

the Multi-Agency Radiological Laboratory Analytical Protocols Manual (MARLAP) and the MultiAgency Radiation Survey and Site Investigation Manual (MARSSIM), both referenced in this

document. EPA is developing companion documents for air and soil samples. Familiarity with

Chapters 2 and 3 of MARLAP will be of significant benefit to the users of this guide.

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

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 contract 68-W-03-038, work assignments 21 and 35, 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 Water

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; 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. 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 Water

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Contents

Acronyms, Abbreviations, Units, and Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi

Radiometric and General Unit Conversions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii

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

A. Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

B. Scope and Radiological Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

C. Analytical Response Time .................................................6

D. Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

E. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

II. RADIONUCLIDES .........................................................9

III. DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

IV. CROSSWALK of Data Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

V. RADIOANALYTICAL SCENARIO 1 (Identifying Samples with Highest Activities) . . . . 13

VI. RADIOANALYTICAL SCENARIO 2 (Identifying Uncontaminated Drinking Water) . . . 22

VII. RADIOANALYTICAL SCENARIO 3 (Contaminating Radionuclides are Known) . . . 28

Appendix I. Tables of Radioanalytical Parameters for Radionuclides of Concern . . . . . . . . . . . 32

APPENDIX II. Example of High Radionuclide Concentration in Water (Radioanalytical Scenario

1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Event Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Analysis Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

APPENDIX III. Example of Finding a Potable Water Source (Radioanalytical Scenario 2) . . . 43

Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Event Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Analysis Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

APPENDIX IV. Radionuclide Contaminants are Known (Radioanalytical Scenario 3) . . . . . . 46

Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Event Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Analysis Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

APPENDIX V. Representative Analytical Processing Times . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

APPENDIX VI. Establishing DQOs and MQOs for Incident Response Analysis . . . . . . . . . . . 52

APPENDIX VII. Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

v

Figures

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

Figure 2 – Water Scenario 1 Analytical Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Figure 3 – Water Scenario 2 Analytical Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Figure 4 – Water Scenario 3 Analytical Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Figure 5 – Approximate Timeframe for Radiochemical Analyses (Radioanalytical Scenario 1) . 49

Figure 6 – Approximate Timeframe for Radiochemical Analyses (Radioanalytical Scenario 2) . 50

Figure 7 – Approximate Timeframe for Radiochemical Analyses (Radioanalytical Scenario 3) . 51

Figure 8 – A Decision Point in a Flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Figure 9 – The Data Quality Objectives Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

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

the AAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

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

Exceed the AAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Tables

Table 1 – Radionuclides of Concern ................................................ 9

Table 2 – Crosswalk of PAG, SDWA Limits, AAL, ADL, and uMR Values . . . . . . . . . . . . . . . . . 12

Table 3 – Radionuclides with Low-Abundance Gamma Rays Not Usually Used For 

Their Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Table 4 – Beta “Only” Emitters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Table 5A – Analytical Decision Levels (ADL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Table 5B – Analytical Decision Levels (ADL) For Gross Beta or Gamma Screening Analysis . 33

Table 6A – Required Method Uncertainties for Alpha-Emitting Radionuclides at 100-mrem AAL

When Using Radionuclide-Specific Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Table 6B – Required Method Uncertainties for Beta- or Gamma-Emitting Radionuclides at 100-mrem

AAL When Using Radionuclide-Specific Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Table 7A – Maximum Contaminant Levels (MCL) and Required Detection Levels (RDL) for AlphaEmitting Radionuclides in Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Table 7B – Maximum Contaminant Levels (MCL) and Required Detection Levels (RDL) for

Beta/Gamma-Ray Emitting Radionuclides in Drinking Water . . . . . . . . . . . . . . . . . . . . . . . . 37

Table 8A – The DQO Process Applied to a Decision Point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Table 8B – Possible Decision Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Table 8C – The DQO Process Applied to a Decision Point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Table 8D – Values of z1-" (or z1–$) for Some Commonly Used Values of " (or $) . . . . . . . . . . . . 56

Table 9A – DQOs and MQOs for Radioanalytical Scenario 1. Prioritization Decisions Based on

Screening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Table 9B – DQOs and MQOs for Scenario 1. Values Reported Externally Based on RadionuclideSpecific Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Table 10A – Derived Water Concentrations (DWC) Corresponding to "-Emitting Radionuclide

Analytical Action Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Table 10B – Derived Water Concentrations (DWC) Corresponding to $-Emitting 

Radionuclide AALs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Table 11A – DQOs and MQOs for Scenario 2. Internal Lab Prioritization Decisions Based on

Screening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Table 11B – DQOs and MQOs for Scenario 2. Values Reported Externally Based on RadionuclideSpecific Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Table 12 – Minimum Detection Concentration Values for Various Counting Times and Sample

Volumes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

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Acronyms, Abbreviations, Units, and Symbols

(Excluding chemical symbols and formulas)

" . . . . . . . . . . . alpha particle

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

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

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

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

$ . . . . . . . . . . . beta particle

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

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

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

1980 (“Superfund”)

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

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

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

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

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

DWC . . . . . . . derived water concentration 

e– . . . . . . . . . . . electron

E$max . . . . . . . . maximum energy of the beta-particle emission

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

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

( . . . . . . . . . . . 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

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

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

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

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

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

keV . . . . . . . . . thousand electron volts

L ........... liter
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

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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

MCL . . . . . . . . maximum contaminant level

MeV . . . . . . . . million electron volts

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

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

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

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

:R . . . . . . . . . microroengten

MDC . . . . . . . minimum detectable concentration

min . . . . . . . . . minute

MQO . . . . . . . measurement quality objective

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

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

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

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

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

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

R . . . . . . . . . . . roentgten

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

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

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

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

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

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

SDWA . . . . . . Safe Drinking Water Act

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

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

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 Water

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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

103

pCi

pCi/g

pCi/L

Bq/L

Bq

Bq/kg

Bq/m3

Bq/m3

3.70 × 10–2

37.0

37.0

10–3

microcuries per

milliliter

(:Ci/mL)

pCi/L 109 pCi/L :Ci/mL 10–9

disintegrations

per minute (dpm)

:Ci

pCi

4.50 × 10–7

4.50 × 10–1

pCi dpm 2.22

gallons (gal) liters (L) 3.78 L gal 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 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 Water

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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 water samples that may have been contaminated as the result

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

nuclear device (IND), or an intentional release of radioactive materials into a drinking water supply.

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, priorities, and requirements

of each phase. Some of the more important radioanalytical laboratory resources germane to incident

response and recovery consist of radionuclide identification and quantification capability, sample

load capacity, 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 are used. During this phase, responders are primarily

concerned with evacuating people, sheltering them in place, or restricting use of specific water

supplies. 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 require evacuation of a population if the projected short-term total effective radiation

dose equivalent1

 (TEDE) exceeds 5 rem.2 The nominal trigger for sheltering is 1–5 rem over four

days (projected avoided total effective dose). The radioanalytical resource requirements (field or

fixed laboratory) for this early phase may vary significantly depending on the timeframe, source

term radionuclide 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 levels (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 derived water concentrations (DWCs) are based on the PAGs or risk values. For 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.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

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The final, or “recovery,” phase occurs as part of a radiological incident site- or drinking-watersupply remediation effort. During this final phase, when site- or drinking-water-supply characterization and remediation cleanup effectiveness is determined, there is a potential for more extensive

radiochemical analyses at the lowest radionuclide concentrations. Applicable drinking water

regulations for radionuclides (40 CFR Parts 9, 141, 142) may be used during this phase.

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

radionuclide source terms, quantification of the radionuclides in a variety of media, and the gross

radiation screening of samples for prioritization of sample processing or for information related to

the general level of contamination. This guide has been developed to provide the Incident

Commander (IC) and the laboratories selected to analyze samples during an incident with a logical

processing scheme to prioritize sample processing in relation to the radionuclide derived water

concentrations corresponding to established PAGs or Maximum Contaminant Levels (MCLs) under

the Safe Drinking Water Act.

A. Objectives

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

rapid support to Agency personnel following a radiological or nuclear incident. Because EPA

recognizes that in the immediate and intermediate period following such a release, there may not

be sufficient time for the Incident Command Center (ICC) to coordinate and communicate complete

data quality objectives, measurement quality objectives, and analytical priorities to the laboratory,

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

reporting appropriate data suitable for the anticipated use.

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

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

drinking water regulations for radionuclides (40 CFR Parts 9, 141, and 142, National Primary

Drinking Water Regulations; Radionuclides; Final Rule. Federal Register 65:76707-76753,

December 7, 2000).

This document presents a series of three analytical scenarios to aid laboratories in establishing

priorities for analyzing samples received during the response to a radiological or nuclear incident.

The following table summarizes the relevant responsibilities of the IC and the laboratory manager

during such a response.

Information

Provided...

Sample

Priority

Method

Uncertainty

Miscellaneous

MQOs

Reporting

(Results and Anomalies)

Analyte

Selection

Turnaround Time

Compliance

Procedure

Selection

By: IC IC IC Lab IC Lab Lab

To: Lab Lab Lab IC Lab IC IC

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 required measurement quality objectives (MQOs) and the required turnaround time. It is possible

that immediately following such an event, especially when MQOs may not have been established

or provided, laboratories may receive samples without complete documentation or direction. In such
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

3

cases, laboratories may follow the procedures and examples in this document, and be confident that

their results should 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 on 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. Familiarity with Chapters 2 and 3 of

MARLAP will be of significant benefit to the users of this guide.

B. Scope and Radiological Scenarios

Radiological incidents can be subdivided into three phases: 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. During the intermediate phase, the radionuclides and

matrices of concern are known qualitatively, and the quantitative levels suitable for making

decisions based on analytical action levels need to be rapidly determined. The phase 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 focus on rapid turnaround of sample

results and optimized sample analysis so that the initial qualitative aspects and concentrations related

to the appropriate AALs can be determined quickly. During the recovery phase, the screening

techniques used for samples will be of less significance 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. Potable water supplies will be evaluated

against MCLs during this recovery phase.

Three distinct radioanalytical scenarios are presented for water potentially contaminated with

radionuclides. The first two assume that the radionuclides are unknown.

 • The first scenario is a water supply, surface, or groundwater source highly contaminated with

an unknown quantity of yet unidentified radionuclides.

 • The second scenario requires that the laboratory determine whether a water source from the

affected areas and unknown source term is safe to drink.

 • The third scenario, where the radionuclides have been identified, occurs later during the early

or intermediate phases, and the laboratory need not waste analytical processing time trying to

identify which radionuclides are present. The decision tree focuses on establishing the priority

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

radionuclides.

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 concentrations in the water sources sampled.

The need to identify safe sources of drinking water (Radioanalytical Scenario 2) will occur later in
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

4

the intermediate phase and into the recovery phase. Once all the radionuclides are identified,

Radioanalytical Scenario 3 may be used for either scenario, depending upon the direction of the IC.

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 late-intermediate to recovery phase.

Figure 1 depicts how these three radioanalytical scenarios relate to the response team’s needs for

sample prioritization.

In the third scenario, the radionuclides have been identified. This situation can arise during any of

the phases, so while Figure 1 depicts Scenario 3 occurring during the later intermediate phase,

Scenario 3 could occur earlier. The laboratory can save time by analyzing samples for its specific

radionuclides, after it has had a gross screen to determine sample-processing priority based on its

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

when assessing the water as a potential drinking water source.

As introduced earlier, PAGs establish radiation dose limits applicable to different phases of an

incident response. The drinking water PAG (expressed as a numerical dose level) indicates a level

of exposure at which protective action should be taken to prevent, reduce, or limit a person’s

radiation dose during a radiological incident. The derived water concentration (DWC) is the

concentration of a radionuclide in water corresponding to the PAG dose and is used to facilitate the

application of PAGs in the radioanalytical laboratory. For example, the concentration of 137Cs in

drinking water corresponding to the 500-mrem PAG is 5.8×104

 pCi/L.

Similarly, radionuclide DWCs corresponding to other specific dose or risk value may be calculated

and applied as required. The term “analytical action level” (AAL) will be used as a general term

denoting the radionuclide concentration at which action must be taken by incident responders.

Early Phase Intermediate Phase Recovery Phase

Unknown Radionuclides

(Radioanalytical Scenario 1)

Sample

priority based on

concentration

Low*

High*

Gross

quantification

Radionuclidespecific

identification

Radioanalytical

Scenario 2 

Known Radionuclides

(Radioanalytical Scenario 3)

Radionuclides

known

?

No,

but priority set

low* by OSC Yes

No, but priority set

high* by OSC

Radioanalytical

Scenario 3

priority

Determination of 

radionuclides for PAG

Determination of

radionuclides for MCL

High*

Low*

Day 3 Following Event Weeks to Months Following Event

*Note: ”High” and “Low”

refer to processing

priorities, not activity

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

1

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

2

See Appendix VI, Table 10A.

3

Tables 5A and 5B in Appendix I summarize default ADLs and uMR for screening measurements.

4

Tables 6A and 6B in Appendix I summarize default ADLs and uMR for radionuclide-specific measurements.

5

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.

When applied to prioritizing samples for processing, 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 objectives (DQO)/MQO process.1

 In this process, the

MQO of greatest significance is the required method uncertainty, uMR. An example of a dose and its

corresponding AAL, ADL, and uMR is shown here for 226Ra (based on tolerable Type I and Type II

error rates; see details in Appendix VI):

Measurement Type Dose (mrem) AAL2 (pCi/L) ADL (pCi/L) uMR (pCi/L)

Screening3 100 180 90 54

Radionuclide-specific4 100 180 130 22

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 corresponding ADL values are provided for screening and radionuclidespecific analyses. The default values for uMR and corresponding ADL for screening and radionuclidespecific determinations presented in Tables 5A, 5B, 6A, and 6B provide laboratories with a starting

point for developing protocols and systems for incident response activities. It is anticipated that in

the case of an incident, specific DQOs and MQOs may be developed by Agency personnel to reflect

the specific nature and concerns of the incident and provided to the laboratory.

Decisions related to water quality suitable for drinking are based on specific regulatory values based

on the Safe Drinking Water Act (SDWA). In this case, specific values for the Maximum

Contaminant Level (MCL) and the Required Detection Level (RDL) are applicable for each

radionuclide, as well as gross " and $ (see Tables 7A and 7B). If more than one beta- or gammaemitting radionuclide is present, the “sum of fractions” rule applies. This is best illustrated in the

example found in Appendix II, Scenario 1, Step 15. The “sum of fractions” rule does not apply to

alpha-emitting radionuclides.

The flow diagrams and corresponding numbered notes and data tables depict the analytical

processing suggested for rapid response and consistency. In keeping with concepts of the MultiAgency Radiological Laboratory Analytical Protocols (MARLAP) Manual, 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 the IC.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

6

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 3 (EPA 600-R-07-015).

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 AAL, could be:

“A method uncertainty of 50 pCi/L or less is required for 241Am analysis at the 100-

mrem AAL of 400 pCi/L.”

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 performance data to

demonstrate the method’s ability to achieve the project-specific MQOs. Method validation and

continued acceptable method performance assessments are essential to the performance-based

approach to method selection.

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

events and may need to be modified by the IC 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—primarily in the

form of required method uncertainties—for analyzing the radionuclides of concern. For example,

at most decision points in the diagrams where a quantitative value is given, a uMR at that AAL is

identified in the notes and the tables. The uMR values are identified in Tables 5A, 5B, 6A, and 6B of

Appendix I. Appendix VI describes the methodology used to establish the required method

uncertainties identified in these tables. It is important to note that the ADL values specified in

Appendix I are less than the PAGs or AALs stated in Appendix VI, Tables 10A and 10B, by the

statistical factors identified in Appendix VI. In a few cases, an MQO in the form of a Required

Detection Limit is used. These decision points have action limits (MCLs and RDLs) that are

specified by regulation (i.e., the Safe Drinking Water Act). These are specifically identified in

Tables 7A and 7B in Appendix I. In these instances, the measured value need only be less than the

MCL to be within the limits of the regulation, and the sample-specific detection limit need only be

less than or equal to the RDL.

Once the appropriate method has been selected, then based on the required method uncertainty or

required detection limit, the laboratory can select the proper aliquant size, counting time and other

parameters to meet the MQOs in the most efficient manner.

C. Analytical Response Time

Decisions regarding the extent of contamination in surface and groundwater supplies 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. This identifies the workflow for making

qualitative and quantitative measurements of high-activity contaminated water samples (Radioanalytical Scenario 1). In addition, results of the sample radioanalytical measurements needs to be

communicated promptly by the laboratory to the IC so that decisions regarding movement of
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

7

population, sheltering, and additional sampling can be made.

D. Implementation

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

operating procedures. 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.

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

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

familiar with the recommendations and procedures, and laboratories should consider 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

functions. This will help to ensure sample analysis continuity throughout the length of the incident

response.

Certain values are identified in the tables in this document for presumptive AALs, which may be

relied upon in the absence of explicit action levels received from the Incident Command Center, so

that the laboratory may begin to process samples promptly. 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.

E. References

American Public Health Association (APHA), American Water Works Association (AWWA), and

Water Environment Federation (WEF). 2005. Standard Methods for the Examination of Water

and Wastewater, 21st Edition. Available for purchase from www.standardmethods.org/. (See

note following this list for additional information on approved standard methods.)

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/rpdweb00/rert/pags.html.

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/radionuclides/pdfs/

regulation_radionuclides_rulemaking_techsupportdoc.pdf.

U.S. Environmental Protection Agency (EPA). 2000. 40 CFR Parts 9, 141, and 142, National

Primary Drinking Water Regulations; Radionuclides; Final Rule. Federal Register 65:76707-
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

8

76753, December 7. Available at: www.epa.gov/safewater/radionuclides/regulation.html.

U.S. Environmental Protection Agency (EPA). 2001. OSWER Directive 9283.1-14, Appendix B:

“Use of Uranium Drinking Water Standards under 40 CFR 141 and 40 CFR 192 as Remediation

Goals for Groundwater at CERCLA sites.” November 6. Available at: www.epa.gov/superfund/

health/contaminants/radiation/pdfs/9283_1_14.pdf.

U.S. Environmental Protection Agency (EPA). 2002. “Final Implementation Guidance for Radionuclides,” EPA 816-F-00-002. 40 CFR 141.26(a)(2)(iii). Available at: www.epa.gov/safewater/

radionuclides/compliancehelp.html.

U.S. Environmental Protection Agency (EPA). 2003. Response Protocol Toolbox: Planning for and

Responding to Drinking Water Contamination Threats and Incidents. Interim Final – December.

Office of Water. EPA817-D-03-001 through EPA-817-D-03-007. Available at: http://cfpub.epa.

gov/safewater/watersecurity/home.cfm?program_id=8#response_toolbox.

U.S. Environmental Protection Agency (EPA). 2006. Guidance on Systematic Planning Using the

Data Quality Objectives Process (EPA QA/G-4). EPA/240/B-06/001. Office of Environmental

Information, Washington, DC. Available at: www.epa.gov/quality/qs-docs/g4-final.pdf.

U.S. Environmental Protection Agency (EPA). 2007a. Standardized Analytical Methods for

Environmental Restoration following Homeland Security Events. Revision 3. EPA 600-R-07-

015. National Homeland Security Research Center, Office of Research and Development.

Available at: www.epa.gov/nhsrc/pubs/reportSAM030107.pdf.

U.S. Environmental Protection Agency (EPA). 2007b. Method Validation Requirements for

Qualifying Methods Used by Radioanalytical Laboratories Participating in Incident Response

Activities. Revision 0. Office of Radiation and Indoor Air. Unpublished; undergoing final

review.

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/84.html.

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

p.123.

U.S. Department of Homeland Security (DHS). 2004. Nuclear/Radiological Incident Annex to the

National Response Plan. NUC-1. Available at: hps.org/documents/NRPNuclearAnnex.pdf.

Multi-Agency Radiological Laboratory Analytical Protocols Manual (MARLAP). 2004. EPA 402-B04-001A, July. Volume I, Chapters 3, 6, Volume II. Available at: www.epa.gov/radiation/

marlap.

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

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

www.epa.gov/radiation/marssim/.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

9

Approved Standard Methods for the Examination of Water and Wastewater, required for analyses

under Radioanalytical Scenario 2, include the following. Analysis of the radionuclides discussed in

the following section with procedures from other standard organizations may be acceptable (see 40

CFR 141.25 for alternative methods).

 • 7110 Gross Alpha and Gross Beta Radioactivity (Total, Suspended, and Dissolved) (3 methods)

 • 7120 Gamma-Emitting Radionuclides (2 methods) 

 • 7500-3H Tritium (2 methods) 

 • 7500-Cs Radioactive Cesium (2 methods) 

 • 7500-I Radioactive Iodine (2 methods) 

 • 7500-Ra Radium (5 methods) 

 • 7500-Sr Total Radioactive Strontium and Strontium-90 (2 methods) 

 • 7500-U Uranium (3 methods)

II. RADIONUCLIDES

Table 1 lists some of the radionuclides that are believed to be accessible and possibly could be used

in a radiological dispersion device (RDD)—or “dirty bomb”—or used to contaminate a drinking

water supply, and which are addressed in this report.

This list is specifically for a RDD event and the major (noninclusive) dose-related radionuclides that

might be formed from the detonation of an improvised nuclear device (IND). In the case of a IND,

numerous short- and long-lived fission product 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 is 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 1 – Radionuclides of Concern

Radionuclides

Alpha Emitters

Radionuclides

Beta/Gamma Emitters

Am-241 Ra-226 Ac-227† Mo-99†

Cm-242 Th-228 Ce-141* P-32*

Cm-243 Th-230 Ce-144‡ Pd-103*

Cm-244 Th-232 Co-57* Pu-241

Np-237 U-234 Co-60* Ra-228 

Po-210* U-235 Cs-134* Ru-103†

Pu-238 U-238 Cs-137§ Ru-106†

Pu-239 U-Nat H-3* Se-75*

Pu-240 I-125* Sr-89*

I-129† Sr-90†

I-131* Tc-99*

Ir-192*

*

 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 Water

10

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.

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

analysis by the laboratory will be short (under one day). Therefore, samples received by the

laboratory will not be preserved, nor will they have been filtered. Sample filtration generally should

not be performed until the extent of contamination and the radionuclide identity(ies) are known. The

final decision on this must be communicated to the laboratory by the IC based on the project MQOs.

Should it be necessary to delay analysis for any sample for more than two days, the sample should

be preserved according to the analysis protocols to be determined.

For the three scenarios discussed in this guide, it is assumed that field personnel have performed

some type of radiation detection 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.

Only qualified laboratories using validated radioanalytical methods (see EPA 2007b 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 sample-processing capacity to

conduct the required gross screening and radionuclide-specific analyses defined for the radioanalytical 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. Specific analytical techniques applied after screening indicates the most significant activities.

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

point in the flow diagram relates to an AAL (based on a PAG DWC, regulation, or risk-based DWC)

that is part of the overall analytical process. The flow diagrams for the three radioanalytical

scenarios (Figures 2, 3, and 4) use simplified process-control shapes: diamonds represent decision

choices, and rectangles are action or information steps. The numerical limits in the diamonds of the

flow diagrams are ADLs. Many of the flow diagram shapes have numbers keyed to the notes

immediately following the respective figures. Most 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

Appendices II, III, and IV. Consequently, it is highly advisable to study the flow paths in color, as

a black-and-white version may be confusing or ambiguous.

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:
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

11

 • 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.

 • Survey meters with appropriate alpha, beta, and gamma detector probes can be used to determine

whether samples exceed the maximum dose rate that can be handled or analyzed at the

laboratory.

The instrument used for gross screening analysis (mostly for ( radiation) should be calibrated

(pCi/net dose rate) with a 137Cs source of appropriate geometry.

The laboratory also should have the instrumentation to perform radionuclide-specific analyses (e.g.,

high-purity germanium [HPGe] detectors for gamma and ion implanted silicon detectors for alpha

spectrometry). Some of the radionuclides listed in Table 1 on page 9 (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 energy for many HPGe calibrations).

Each numbered box has associated with it a 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.

Table 12 (Appendix VI) provides estimated counting times for LSC and GPC and the minimum

detectable concentration (MDC) that can be achieved by screening a small sample aliquant for gross

alpha and beta activity. The values are based on typical detector efficiency and background values

for two methods, gas proportional and liquid scintillation counting. Laboratories should prepare their

own MDC tables using their preferred detection method as part of their standard operating

procedures (SOPs). Laboratories also should determine (in advance) whether their individual

analytical protocols will need to be revised to accommodate this process.

The number of samples that will be analyzed, and their level of contamination, will be significantly

higher than normal samples. Laboratories must also consider the following:

 • Separate sets of procedures for sample handling and storage.

 • Increasing the frequency of detector background analyses.

 • Increasing the frequency of QC checks.

 • Consider 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.

 • Separate protocols for personnel protective equipment.

 • Separate protocols for personnel and sample radiation monitoring.

 • Separate storage location for high-activity samples or a large group of samples, which would

increase laboratory background for detectors or personnel. This storage location may need

additional shielding or be sited so as not to affect operations.

It should be noted that modern radioanalytical procedures in the United States address low ambient

concentrations of environmental radionuclides normally encountered during the past 30 years. With

the detonation of an RDD or IND involving radionuclides with radioactive progeny, it is possible

that the radioactive equilibria involved with these progeny may have been established (depending
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

12

on the time between creation of the radionuclide source to detonation or the time of detonation to

sampling, or both). This means that not only will there be considerably higher concentration of the

parent but of each of the progeny. Furthermore, if multiple radionuclides are involved, the crosscontamination factor during separations must be minimized, a phenomenon that current day analysts

may not have previously experienced. A specific example of such a phenomenon would be the

elimination of 140Ba during the 90Sr separation process. Many processing schemes in today’s

laboratories do not account for this step because many samples are collected over a period of weeks

to months and provided to laboratories as composites. Routine turnaround time for 90Sr analysis is

30 days. Thus, even if the 12-day 140Ba radionuclide is present, it would have decayed significantly

by the time the laboratory receives the sample for analysis.

IV. CROSSWALK of Data Values

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

listed below:

TABLE 2 – Crosswalk of PAG, SDWA Limits, AAL, ADL, and uMR Values

SDWA Required

Limits AAL ADL uMR

500 mrem/100 mrem

(Screening)

Tables 10A and

10B (PAGs) — Tables 5A and 5B Tables 5A and 5B

100 mrem

(Radionuclide Specific) —

Tables 10A

and 10B

(PAGs)

Tables 6A and 6B Tables 6A and 6B

SDWA MCL Values Tables 7A and 7B — — —

SDWA RDL Values Tables 7A and 7B — — —

DQO and MQO

Derivations — — Tables 9A, 9B,11A, and 11B

Tables 9A, 9B,

11A and 11B

Estimated Counting

time for MDC (based on

screening analysis)

Table 12 — — —

EPA’s Response Protocol Toolbox (EPA, 2003) provides additional recommendations concerning

planning and threat management, site characterization and sampling, and sample analysis to assist

utilities and state and local agencies. If laboratory protocols for normal or routine situations cannot

ensure that the DQOs and MQOs are achievable with the laboratory’s SOPs under emergency

conditions, then a separate set of SOPs for emergency conditions will need to be developed. 
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

13

V. RADIOANALYTICAL SCENARIO 1 (Identifying Samples with Highest Activities)

Water Sample Scenario 1

• Unknown radionuclides

• Priority to those samples with highest activities

1a.

Rapid lab

scan of sample>

2.9x104 pCi/L?

(Appendix VI 

Table 9a)

*

9.

Concentration >

2.0x102 pCi/L α or

1.2x103 pCi/L β, or

7.1x AAL for γ, or

7.5×105 3H?

(Appendix I)

2. Rapid analysis (5 mL) 

for gamma spectrometry 

and gross alpha & beta

Yes

No

Yes

10. Routine specific gamma, 

alpha, and beta analyses: 

intermediate-level activity

Yes

11.

β/γ ratio >

2.5 ?

No

Perform 

90Sr & 89Sr 

analyses

Yes

12. Gross α and β using 

250-mL aliquants by GPC

No

Analysis completed 

and reviewed.

13.

Gross alpha

<15 and 

gross beta 

<50 pCi/L

?

14. Routine, specific 

γ, α, and β analyses: 

Low-level activity

Yes

16. Archive sample 

residuals for longterm assessment.

Contact IC.

No 4. Alpha 

emitters by 

chemical

separations

5. Beta 

emitters by 

chemical 

separations

6. Longer gamma 

spec count to look 

for low-activity 

nuclides (5–50 mL)

4. Alpha 

emitters by 

chemical

separations

5. Beta 

emitters by 

chemical 

separations

6. Longer gamma 

spec count to look 

for low-activity 

nuclides (5–50 mL)

Highest priority

Second priority

Lowest priority

End result

Key

See accompanying tables 

for alpha and beta/gamma

concentrations, and 

numbered notes

Highest priority

Second priority

Lowest priority

End result

Key

See accompanying tables 

for alpha and beta/gamma

concentrations, and 

numbered notes

15.

Compares

to gross

analyses

?

Yes

Return to 

Step 2 or 7

No

No

7. Rapid analysis (5 mL) 

for gamma spectrometry 

and gross alpha & beta

17. Archive 

samples for drinking 

water analyses.

3. & 8. 

Concentration >

1.0×103 pCi/L α, or

6.0×103 pCi/L β, or

0.71×AAL for γ, or

3.9×106 3H?

(Appendix I)

3A. Contact IC

* Gross radioactivity 

concentration for Box 1 

corresponds to 137Cs 

based on instrument 

calibration.

1. Perform rapid sample scan 

using gross β/γ instrument

Figure 2 – Water Scenario 1 Analytical Flow
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

1

 Depending on the time of the response, a 2-rem PAG may be applicable. If so, values for this may be obtained by

scaling the PAGs and the ADLs by multiplying their corresponding 100-mrem values by 20. Thus the 2-rem PAG and

ADL for 137Cs would be 2.4×105

 and 1.2×105, respectively.

2

 Some manufacturers have developed kits that include the survey meter plus an alpha–beta–gamma pancake GM

detector and a NaI gamma detector.

14

Notes to Scenario 1: Contaminating Radionuclides Unknown

Purpose: Priority to Those Samples with Highest Activities

Highest priority samples are all analyzed first. Only after an analytical step or procedure

has been completed for the highest priority samples should lower priority samples be

addressed. The samples may arrive over several days; those with the highest priority are

always to be analyzed first. Lower priority samples (those following the green and yellow

flow paths on this chart) may need to be stored for several days until the highest priority

samples have been analyzed.

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 blackand-white printing may be confusing or ambiguous. 

Analysis at this point is to assess if the 500-mrem AAL1 1. values are exceeded by

measurement of the sample’s total gross radioactivity (concentration) with hand-held survey

instruments. These might include a survey meter or Geiger-Muller (GM) counter with

appropriately calibrated beta and gamma detector probes or a micro-roentgen meter (gamma

only).2

 This step would most likely be performed with the sample container, unopened,

leaving the determination of " ADLs to the next step. Unless the identification of the

radionuclide contamination is known, the hand-held survey instrument should be calibrated

using a 137Cs source that would replicate the sample container geometry. The subsequent

measurement should be capable of identifying a concentration from zero to 5.8×104

 pCi/L,

which is the 500-mrem AAL for 137Cs. The ADL for this screening analysis is 2.9×104

 pCi/L

when applied to unknown radionuclides (see Appendix VI, Table 9A, on page 57). If the

identification of the radionuclide(s) is known, the Analytical Detection Level (based on the

AAL for the radionuclide listed for the 500-mrem value) is to be used (see Appendix I,

Tables 5A and 5B). For survey instruments having an exposure rate readout, the instruments

should be calibrated in terms of pCi/L per exposure unit readout for each container geometry

expected and for the nuclide of interest, if known (137Cs for unidentified nuclides).

Some laboratories may also use a calibrated NaI(Tl) detector to assess gross ( activity level

(using an integrated spectrum technique) and relate this measurement to a gross or

radionuclide-specific ( ADL.

Some gamma-emitting nuclides may not be detected at their ADLs if the sensitivity of the

instrument used is inadequate. Tritium will not be detected, and beta-emitting radionuclides
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

1

These values are based on the ADL values for 241Am and 90Sr, respectively. The assumption is that the detection device

is calibrated with 137Cs and will yield the most representative gross activity measurement at this point in the screening

process. The gamma ADL is 0.71×AAL value for any individual gamma ray emitter.

2

 LSC screening of samples typically is preferred over GPC because sample preparation of a 5-mL aliquant is much

simpler, less time-consuming, and minimizes the risk of contamination. In addition, for the same counting time, LSC

screening for this AAL has a better detection capability compared to GPC.

15

that do not emit (- or X-rays may not be detected depending on the window thickness of the

detector.

The initial results of these measurements need to be checked against the information in the

chain-of-custody form. Communication of preliminary findings to the IC may be very

valuable in helping the IC determine the areas that may need additional samples. This

feedback also will reinforce the priorities assigned to each sample and further enhance

decision making.

If the gross activity scan yields a value greater than 2.9×104 1a. pCi/L, go to Step 2 (red path).

Otherwise, go to Step 7 (green path).

NOTE: The gross radioactivity measurements under Note 2 are evaluated against the ADLs listed

in Table 5B for 241Am, 90Sr and 60Co, respectively, at the 500-mrem level. These are not the lowest

ADL values for all radionuclides. Thus, no conclusions about the presence or absence of other

radionuclides should be made at this point in the analytical process.

2. If the gross ", $, or ( activities of these samples indicate that an AAL may have been

exceeded (i.e., the sample activity is greater than one of these ADL values: 1.0×103 alpha,

or 6.0×103 $, or [0.71×AAL] for an individual ( pCi/L1

), then these analyses have the

highest priority. Rapid analytical techniques, using a 5-mL sample aliquant, for " and $ by

either liquid scintillation counting (LSC)2

 or gas proportional counting (GPC) should be

done to assess the individual levels of these components of the mixture. Additionally, a rapid

gamma isotopic analysis needs to be performed using a HPGe detector. Note that, dependent

upon the type of instrument used, the count time for some analyses may be shorter with LSC

than with GPC. Screening for radionuclides such as 125/129/131I by GPC may need to be

carefully performed to prevent loss of radionuclide analyte due to volatilization during

sample evaporation.

Gamma isotopic analysis is performed with a high-purity germanium (HPGe) detector to

identify the major ( emitters. Analysis should be made on the original sample container or

on an aliquant as small as 20 mL in a standardized counting geometry. The ( isotopic

analysis (original sample container or 20-mL aliquant) of Steps 2 and 7 using a HPGe

detector and a counting time $10 minutes should be satisfactory for achieving the required

method uncertainties for the (-emitting radionuclides in Table 5B (counting time will meet

both the 500- and 100-mrem ADL values).

Tritium, a potential contaminant, will not be detected by either of the gross analysis scans

unless LSC is used to determine gross beta. If GPC is used for gross beta analysis, a separate

aliquant of the sample will need to be analyzed for tritium. Tritium analysis should be
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

1

A technique that has been used successfully to determine the energy of beta-only emitters is to measure the range of

the beta particles in a pure material (“Feather analysis”). The ranges of beta particles in several pure materials (such as

aluminum) have already been established. The units of thickness are expressed as areal density, or mg/cm2

. A set of

aluminum absorbers of varying thickness is used, and the activity versus the absorber thickness is plotted on a semi-log

scale. The linear portion of this curve is then extrapolated to find the “zero” activity thickness. This is then related to

the E$max of the beta particle, which will be characteristic for a particular radionuclide. A discussion of this technique

can be found in Principles of Radioisotope Methodology, 3rd Edition, G.D. Chase and J.L. Rabinowitz, Burgess

(Minneapolis) 1967.

16

performed during this stage of the analytical process. The ADL for tritium at this stage is

3.9×106

 pCi/L.

3. Once the rapid analyses have been performed, the data should be reviewed to verify that the

screening ADL concentrations have or have not been exceeded:

• 1.0×103 " pCi/L corresponding to 241Am

• 6.0×103 $ pCi/L corresponding to 90Sr

• the (-specific concentrations listed

• 3.9×106

 for 3H

(See the pCi/L values for other individual "- and $-emitting radionuclides listed in Tables

5A and 5B).

This is particularly important for " emitters, because the previous step was the first

measurement of alpha radioactivity. Note that if exceeding the ADLs is not confirmed by

at least one of the three analyses, the sample analysis reverts to the second priority analysis

path.

Sample analysis prioritization will be based upon which ADL is exceeded. The ( analysis

may help to assess which of the specific radionuclide analyses needs to be pursued with the

highest priority. For example, if gross " activity exceeds the ADL and the ( radionuclides

identified account for the observed gross $ activity, for which no individual $- or (-emitting

radionuclide ADL has been exceeded, priority would then shift to specific " emitters. Note

in Table 5B that 57Co, 75Se,103Pd, and 125I are (-emitting nuclides only (these radionuclides

decay via electron capture) and have no contribution to the results of a gross $ analysis.

In a different example, the gross $ indicates an ADL has been exceeded, but the gross "

ADL was not exceeded. In this case, the $ emitter analyses would take priority along with

gamma spectrometry analysis. These together would identify the specific $ components of

the sample. The " analysis could be relegated to a lower priority flow path.

Some additional information may be obtained from the (-ray analysis of those radionuclides

that are principally " or $ emitters and have very low abundance ( rays. These types of

radionuclides may be qualitatively identified in a short count (see Table 3, page 20). Qualitative identification of ( rays from those types of radionuclides may aid the laboratory in

sample analysis prioritization.

High levels of $ activity with no significant specific ( component may warrant an additional

GPC screening technique by using mass absorbers1

 to assess the $-particle energy. A sample

volume greater than 5 mL may be required to effectively assess the range of the particles by
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

17

this method. This could minimize time spent on searching for the radionuclide (see Table

4, page 21).

Following Step 3, the highest activity samples that exceed the 1.0×103

 or 6.0×103 pCi/L

ADL screening levels (gross " or $), 3

H, or specific ADL (-emitting radionuclide concentrations, respectively, should be analyzed through Steps 4, 5, and 6 as quickly as possible. This

will enable the laboratory to recalibrate its gross screening methods for those radionuclides

actually found in the sample, which in turn will improve the accuracy of the gross screening

techniques in assessing whether ADLs have been exceeded for subsequent samples. This

also means that subsequent samples from the same location may be able to follow

Radioanalytical Scenario 3 (page 28).

3a. The existence of samples exceeding the 500-mrem ADLs should be communicated to the

IC as soon as possible.

NOTE: Steps 4, 5, and 6 may be done concurrently based on the gross analysis results.

4. Chemical separation for specific " radionuclides commences if the gross " concentration

exceeds the ADL (see Table 5A, page 32). Certain " emitters also emit ( rays or have (-

emitting decay products that may be identified in Step 3. The ( results can be used to

determine which " emitter analyses need not be performed immediately. For example, lack

of a significant 59 keV peak in the ( spectrum would indicate that an analysis for 241Am does

not have to be performed. If the project manager does not specify the sequence of analyses,

laboratory personnel should use their best professional judgment, based on the characteristics

of the samples, to determine the order of processing the samples so that the results are

obtained in the most efficient manner.

5. Chemical separations to be performed for specific $ radionuclides, not identifiable via

gamma spectrometry, include 3H, 32P, 241Pu, 90Sr, and 89Sr. If the project manager does not

specify the sequence of analyses, laboratory personnel should use their best professional

judgment, based on the characteristics of the samples, to determine the order of processing

the samples so that the results are obtained in the most efficient manner.

6. The initial gamma spectrometry results will have identified high activity samples that may

provide insight as to which "- or $-only emitters are present. This longer count (compared

to Step 7) and optional larger sample size should focus on lower-intensity (-ray lines from

additional radionuclides. When counting is completed, the analyst should ensure that newly

identified (-rays are from different radionuclides and not just low intensity lines from the

predominant ( emitters.

NOTE: Once radionuclides have been identified, gross screening methods should be recalibrated

to the radionuclides of interest, and the laboratory may follow the flowchart for Radioanalytical

Scenario 3.

 7. If the initial gross screening method (Step 1) does not indicate a radioactivity greater than

the ADLs, gross " and $ analyses using a 5-mL sample and a counting time of about 30

minutes should be performed to verify that these ADLs have not been exceeded. The (
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

18

isotopic analysis (original sample container or 5-mL aliquant) of Steps 2 and 7 using a HPGe

detector and a counting time less than 60 minutes may have a detection limit needed to

quantify radionuclides at concentrations corresponding to the 500- or 100-mrem ADLs. If

not, the sample should be counted longer.

Tritium is a potential contaminant that will not be detected by either of the gross analysis

screens unless LSC is used to determine gross beta. If GPC is used for gross beta analysis,

a separate aliquant of the sample will need to be analyzed for tritium by LSC. Tritium

analysis should be performed during this stage of the analytical process. The ADL for tritium

at this stage in the analytical process is 7.5×105

 pCi/L.

 8. Here the results from screening analyses performed in Step 7 are compared to the 500-mrem

ADLs from Tables 5A and 5B (" 1.0×103 or $ 6.0×103), or specific (-emitting radionuclide

ADL concentrations, respectively. If the screening concentrations are greater than these

ADLs, a high priority would be established to analyze the samples for specific radionuclides

in Steps 4, 5, or 6. If the screening results of Step 7 do not exceed the ADLs, then the

question in Step 9 is evaluated.

Does the gross or specific radionuclide concentration exceed the corresponding (" 200 or 9. 

$ 1.2×103)

*

 or specific (-emitting (3.3×103 for 60Co) radionuclide 100-mrem ADL

concentrations, respectively? If “yes,” proceed immediately with subsequent analyses. The

status of samples exceeding the 100-mrem ADLs should be communicated to the IC. If “no,”

go to Step 11.

NOTE: “*” gross concentrations noted above correspond to the 100-mrem ADL values for 241Am

and 90Sr, respectively, listed in Tables 5A and 5B. These are not the lowest concentrations for all

radionuclides, and decisions about the presence of other radionuclides should not be made until

radionuclide-specific analyses have been performed. 

10. Use a routine method that can provide analytical results within about one day. Sample size

and counting time will need to be increased to verify screening levels and to quantify those

radionuclides whose individual concentrations are below their corresponding 100-mrem

ADL values listed in Tables 5A and 5B on pages 32 and 33 (see notes for Steps 4, 5, and 6

for other information on specific radionuclide analyses). 

Calculate the sum of the ratios (individual nuclide concentration/100-mrem AAL are in

Tables 10A and 10B, page 59) of all radionuclide concentrations above their respective RDL

values (Tables 7A and 7B, page 36). If the summed value exceeds unity, then the 100-mrem

AAL has been exceeded even though an individual value does not exceed the ADL (see

example calculation in footnote 2 on page 41).

If the IC does not specify the sequence of analyses, laboratory personnel should use their

best professional judgment, based on the radiological characteristics of the samples and in

order of highest to lowest concentration, to determine the order to process the samples to

produce expeditious results.

A $/( ratio >2.5 (i.e., ratio of gross $ to gross () indicates that 90Sr or 89 11. Sr may be a signifi-
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

19

cant contaminant. Although this decision falls into the low-priority path, this analysis should

be done first for the low-priority samples because of the dose significance of 90Sr and the

time required to do this analysis. Note that for the higher priority flow path, determination

of strontium would be done in parallel with other analyses, so the urgency of its analysis

does not need to be emphasized. Sufficient activity of the sample is necessary to have a

statistically significant $/( ratio. The summed individual ( activities obtained from the

HPGe detector from the printout would need to be applied for this calculation.

12. A GPC gross " and $ analysis of a larger sample (250 mL) and a longer counting time is

warranted. These analyses will determine if either of the MCL values for drinking water (15

" pCi/L or 50 $ pCi/L) has been exceeded. Range determination of $-particle energy (see

footnote on page 16) may be very effective with this 250-mL sample residue. This would

help to further refine which $-only emitter is present at the highest concentration and

deserves the priority analysis.

13. Determine if any gross ", $, or ( sample concentration exceeds the concentration corresponding to the screening MCL. For alpha emitters, this is 15 pCi/L and for beta emitters, this

is 50 pCi/L. The status of any samples exceeding Safe Drinking Water Act standards should

be communicated to the field coordinator.

14. Routine low-level analyses including total radiostrontium should be performed if not already

done. If total radiostrontium results are greater than the ADL, use classical techniques to

identify activities of 89Sr and 90Sr separately. A longer count time ( isotopic analysis should

be completed first. This will assist in the identification of " or $ emitters, which may have

low abundance gamma rays. Additionally, if the ( emitters are parent isotopes for other

radionuclides, this will direct the analyst on which other analyses should be performed first.

Sample size, counting time, and turnaround times shall be adjusted based on the laboratory’s

SOPs for water-compliance monitoring (see notes for Steps 4, 5, and 6 for other information

on specific radionuclide analyses).

If the gross " concentration is between 5 and 15 pCi/L, "-specific radionuclide analysis is

required to identify the radionuclides, including 226Ra. If the gross " concentration is less

than 5 pCi/L, the sample should be analyzed for 228Ra and 226Ra, and by gamma spectrometry

to verify that there are no low-activity ( emitters present.

15. When the high and intermediate priority radionuclide-specific analyses are completed, verify

that no major nuclide has been missed: the sum of the individual nuclide concentrations

(excluding tritium if screening measurement was made by GPC) is approximately equivalent

to the gross activity concentration (a rule of thumb is within a range of about half to twice

the gross value). 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 not yet verified, the sum of the ratios

(individual $- and (-emitter radionuclide concentration/100-mrem AAL are in Table 10B)

of all radionuclide concentrations above their corresponding RDL value (Table 7B) must be

calculated. If the summed value exceeds unity, then the 500-mrem or 100-mrem AAL has

been exceeded, even though an individual radionuclide activity value does not exceed the

respective ADL (see example calculation in Appendix II, Scenario I, Step 15).
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

20

16. All samples should be archived for long-term or follow-up analyses. Those samples having

radionuclide concentrations exceeding concentrations for the 100-mrem ADLs should be

checked for preservation and stored for potential future analysis.

The IC should be notified with specific results for samples and radionuclide concentrations.

17. Archive samples for drinking water analyses. See Tables 7A and 7B for drinking water

MCLs and their required detection limits (RDLs).

Additional Points:

Analysts should recognize that when performing gross " or gross $ analysis by evaporation of a

sample, a significant loss of volatile radionuclides (such as tritium and iodine) will occur. Following

this initial screening technique, the absence of any volatile radionuclides may need to be verified,

depending upon the nature of the event.

Certain "- and $-emitting radionuclides have ( rays that are not used normally for analysis of those

radionuclides, and may not necessarily be identified in gamma spectrometry software. The

combination of gamma-ray abundance and half-life makes the gamma ray of little utility unless there

is a significant mass of the material or the sample is counted for a long time. It is recommended that

a separate library for incident response samples be created that has these ( rays. Table 3 provides

some examples.

TABLE 3 – Radionuclides with Low-Abundance Gamma Rays Not Usually Used For Their Analysis

Radionuclide 89Sr 90Y 129I 210Po 226Ra 228Th

Principal Decay $S $S $S "" "

Gamma, keV 909 1761 40 (32 X-ray)* 80.3 186 (262)* 84

Abundance, % 9.5×10–4 1.1×10–2 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 " " " "" " "

Gamma, keV 911

(from 228Ac)

185.7 86.5 55.3 112.9 54.3 59.5

Abundance, % 27.2 54 12.6 4.7×10–2 4.8×10–2 5.2×10–2 35.7

Radionuclide 241Pu 242Pu 243Cm

Principal Decay $S " "

Gamma, KeV 149 44.9 278

Abundance, % 1.9×10–4 4.2×10–2 14 *

 Values in parentheses represent the next most abundant gamma ray.

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

alpha- or beta-specific detection.

Aluminum absorbers can be used to qualitatively identify the presence of radionuclides based on

penetrating ability. Thus, if an aluminum absorber of 6.5 mg/cm2

 is used, and the measured 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
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

21

be stated that the beta particle energy is >0.067 MeV. Table 4 identifies some beta-only emitters

with their energies and range in aluminum absorbers.

TABLE 4 – Beta “Only” Emitters

Radionuclide 241Pu 63Ni 129I 35S 99Tc 32P 90Sr/90Y

Maximum Beta Energy, MeV 0.021 0.067 0.150 0.167 0.294 1.711 (0.546)/2.28 [1]

Range [2] in Aluminum,

mg/cm2

 for E$max

0.8 6.5 27 32 75 800 1,100

Notes:

[1] It may be assumed that 90Sr/90Y will be in secular equilibrium by the time any analysis is started. Thus,

the 2.28 MeV beta particle of 90Y will 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 Water

22

Water Sample Scenario 2

• Unknown radionuclides

• Priority to identifying uncontaminated drinking water

1.

Survey meter 

measures β/γ

<6.0x103

pCi/L

?

Yes

Yes

No

Yes

Highest priority

Second priority

Lowest priority

End result

Key

See accompanying tables 

for alpha and beta/gamma

concentrations, and 

numbered notes

Highest priority

Second priority

Lowest priority

End result

Key

See accompanying tables 

for alpha and beta/gamma

concentrations, and 

numbered notes

No

No

2b.

Gross α

ADL < 1.1x102 and

gross β < 4.1x102

pCi/L

?

14b.

Gross α

ADL < 1.1×102 and

gross β < 4.1×102

pCi/L

?

15. Store samples for 

analysis much later. 

May not be potable.

No

13. Store samples for 

analysis in near future.

Yes

Yes No

4b.

Tritium

<20,000

pCi/L

?

9. Gamma spectrometry

6.

Gross alpha

results

?

< 5 pCi/L

8. Begin analyte-specific 

Ra and α analyses

5-15 pCi/L

>15 pCi/L

10. Check values against MCLs

(see Tables 7A-B in Appendix I) 

for specific radionuclides (Steps 

4, 7, 8, 9).

11.

Exceed any

MCL

?

No

Proceed at Step 3 if 

necessary.

2a. Gross α/β analysis 

of 5- or 10-mL aliquant

17. Potential potable 

water source: Notify IC

14a. Gross α/β analysis 

of 5- or 10-mL aliquant

12b.

U >20 pCi/L

or corrected gross 

α > 15 pCi/L

? 

16. Not potable: 

Notify IC

Yes

Yes

5.

Gross beta

< 50 pCi/L

? 

7. Begin analyte-specific β analyses.

No

4c.

Tritium

<2.0×104 pCi/L

?

4a. 3H analysis

13. Store samples for 

analysis in near future.

No

4a. 3H analysis

Yes

12a. Analyze for 

total uranium

Yes

16. Not potableNotify IC

α emitters

β/γ emitters 3. Analyze by GPC 

with longer counting 

time

Figure 3 – Water Scenario 2 Analytical Flow

VI. RADIOANALYTICAL SCENARIO 2 (Identifying Uncontaminated Drinking Water)
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

1

 Some manufacturers have developed kits that include the survey meter plus an alpha–beta–gamma pancake GM

detector and a NaI gamma detector.

2

 LSC screening of samples typically is preferred over GPC because sample preparation of a 5-mL aliquant is much

simpler, less time-consuming, and avoids possible contamination. 

23

NOTE: The next steps use screening techniques. The MDCs are used as AALs. These values are

based on those routinely achievable using the count times and volumes noted in Table 12 of

Appendix VI.

Notes for Scenario 2: Contaminating Radionuclides Unknown

Purpose: Rapid Identification of a Potable Water Source

Highest priority samples are all analyzed first. Only after an analytical step or procedure

has been completed for the highest priority samples should lower priority samples be

addressed. he samples may arrive over several days; analysis for those with the highest

priority are always started first. Lower priority samples (those following the green and

yellow 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 in this instance

will be the ones with the lowest activity. Gross " and $, and all analyses done to assess

MCL values, must use standard methods approved for drinking water (page 9). This

scenario assumes that the sources being analyzed have already been used as potable water

sources.

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 (olive 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. Screening with a hand-held survey instrument is to be performed as a contact reading on the

outside of the sample container. The purpose of this screen is to eliminate quickly those

samples that are obviously contaminated and thus may not be used as a drinking water

source. Appropriate instruments might include a survey meter or Geiger-Muller counter with

calibrated beta and gamma detector probes or a micro-roentgen meter (gamma only),1

 using

a 137Cs source geometry that would replicate the sample container geometry. The calibration

measurement should be capable of identifying a concentration down to 6.0×103

 pCi/L, which

is half of the 100-mrem AAL for 137Cs. Laboratories will need to develop instrument-specific

calibration SOPs, which include the use of a mock sample container with a radionuclide

source.

2a. Gross alpha and gross beta screening measurements may be performed using a liquid

scintillation counter (LSC)2 or a gas proportional counter (GPC). For LSC, a 5- to 10-mL

sample is mixed with a liquid scintillation cocktail in a LSC vial and counted for

approximately 10 minutes. For GPC, a 5- to 10-mL sample is deposited on a planchet,
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

24

evaporated, and then counted for approximately 30 minutes. Note that, dependent upon the

type of instrument used, the count time for some analyses may be shorter with LSC than

with GPC. The total mass of evaporated residue for GPC analysis may prevent processing

a full 500 mL aliquant. In these cases, a smaller volume and longer count time will be

required.

The ADLs for this part of the analysis are based on the AAL being considered MDC values.

The ADL values are 110 pCi/L gross " and 410 pCi/L gross $ concentration (see Table 11A

in Appendix VI). Table 12 in Appendix VI shows that the MDC values (210 pCi/L and 820

pCi/L) can be achieved with a 10-minute count of a 5-mL sample. Volumes and count times

may be adjusted based on laboratory-specific instrumentation.

Screening for radionuclides such as 125/129/131I will not be able to be performed by GPC unless

the samples are carefully prepared to prevent loss of radioiodines due to volatilization.

Furthermore, radionuclides that decay by electron capture (such as 57Co, 75Se, 103Pd) may not

be able to be screened using GPC. If any of these electron-capture radionuclides are present,

analysis using a low-energy photon detector (LEPD) or a specific separation scheme for each

will be required.

Tritium cannot be screened using GPC techniques, because it will most likely be present as

a tritiated water molecule. LSC should be used routinely for tritium analysis because of

tritium’s very low electron energy and its likely presence as part of a water molecule. For

these reasons, tritium has a special status. If GPC analysis, and both alpha and beta analyses

are less than the ADLs, Steps 4a and 4b must be performed. If LSC analysis is used and both

alpha and beta analyses are less than the ADLs, proceed directly with Step 3.

2b. A concentration less than the ADL for this part of the analysis—110 pCi/L gross " and 410

pCi/L gross $—will identify the samples most likely to have radionuclide concentrations that

are below the Maximum Contaminant Levels (MCLs) for natural radionuclides, as well as

anthropogenic radionuclides.

In subsequent steps, it will be necessary to show that gross " < 15 pCi/L and gross $ < 50

pCi/L (40 CFR Parts 9, 141, and 142, National Primary Drinking Water Regulations;

Radionuclides; Final Rule. Federal Register 65:76707-76753, December 7, 2000).

If the results of either the gross alpha or beta analysis are greater than the ADLs for this step

(which are based on the MDCs in Table 12), the sample should be checked for preservation

and stored for analysis at a later time, to assess the presence of other radionuclides.

3. The gross alpha and beta results should be compared to specific limits from the Safe

Drinking Water Act (Steps 5 and 6). The analyses for gross alpha and beta at these levels

will require a larger sample volume and longer counting times. Gross " and $ analysis by

GPC is a requirement of the SDWA.

NOTE: Steps 3 and 4a (4a only required when GPC analysis is done) should be done in parallel

to expedite the decision for further analyses.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

25

4a. Samples for tritium analysis may need to be either distilled or passed through an ion

exchange resin if the gross beta results indicate significant counts above background (this

could be due to naturally occurring radionuclides and still be less than MCLs). If tritium is

present above the MCL of 20,000 pCi/L, the water source is not suitable for long-term use

as drinking water.

4b. If the high priority sample tritium result is <20,000 pCi/L, a fresh sample aliquant (~ 4 L,

portions of which will be used for separate analyses) should be analyzed for gamma, beta,

and alpha emitting radionuclides (Steps 7, 8, and 9). If tritium concentration is > 20,000

pCi/L, the water is not a suitable drinking water source (Step 16).

4c. If tritium concentration of the low priority sample is >20,000 pCi/L, the water supply is not

suitable as a drinking water source (Step 16). If tritium concentration is < 20,000 pCi/L,

preserve the sample for future analyses (Step 13).

5. Analysis for specific beta emitters (Step 7) will be performed if the gross beta activity is less

than 50 pCi/L. Methods used for specific beta emitters should be able to distinguish among

the various isotopes of a specific element. Gross beta activity greater than 50 pCi/L means

the source may not be suitable as a long-term drinking water supply. The sample should be

checked for preservation and stored for analysis at a later date (Step 13).

6. Gross alpha analysis will need to distinguish among three different levels. Gross alpha

activity between 15 and 35 pCi/L shall be analyzed for uranium contributions (Step 12). The

uranium result is subtracted from the gross alpha result to determine gross alpha exclusive

of uranium.

If gross alpha is between 5 and 15 pCi/L, alpha-specific radionuclide analysis is required to

identify the radionuclides, with 228Ra and 226Ra taking priority. After or at the same time as

these analyses, gamma spectrometry should be performed to assess presence of any gamma

emitters. 

Finally, if the gross alpha is less than 5 pCi/L, the sample should be analyzed for 228Ra and

226Ra, and by gamma spectrometry to verify that there are no low-activity gamma emitters

present. The project manager may request additional radionuclide-specific analysis for manmade alpha emitters. 

7. Chemical separation to be performed for pure $-emitting radionuclides not identifiable using

gamma spectrometry include—but are not limited to— 3H (Step 4), 90Sr, 89Sr, 99Tc, 241Pu, and

32P. Sr-90 and 89Sr would have the highest priority if project management guidance is not

provided. This step is done in parallel with Step 9.

8. Gross alpha activity between the detection limit and 15 pCi/L may indicate presence of

anthropogenic alpha emitters or naturally occurring radium radionuclides. The exact nature

of the activity should be verified, because these samples are the result of contamination.

Samples should be analyzed for 228Ra and 226Ra.

Samples for gamma spectrometry analysis should be counted long enough to meet the 134 9. Cs

RDL of 10 pCi/L. The count time is dependent on the sample size, background, and detector
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

1

 LSC screening of samples typically is preferred over GPC because sample preparation of a 5-mL aliquant is much

simpler, less time-consuming, and avoids possible contamination.

26

efficiency (this will be a laboratory-specific counting time; 1-3 hours is an approximate

value). The software library should include lines for the predominant gammas of all products

in the U and Th natural decay series as well as any anthropogenic radionuclide with a halflife of greater than 1 day. The purpose of including these naturally occurring gamma-ray

peaks in the library is to ensure complete identification of all gamma rays. Due to

differential solubilities of the progeny of U, Th, and Ra, no assumptions or predictions can

be made regarding the presence of the parents unless specific radiochemical separations are

performed. Gamma analyses should be performed in parallel with the alpha- and betaspecific analyses. This step is done in parallel with Step 7.

10. Here the results from analyses performed in Steps 4a, 7, 8, and 9 are compared to their

respective MCLs (Tables 7A and 7B, Appendix I).

11. If any radionuclide exceeds its MCL, the source should not be considered potable (Step 16).

For beta emitters, the sum of the ratios (individual nuclide concentration/MCL value) of all

concentrations greater than the RDL values must be calculated. If the sum of the fractions

of all $ and (-emitting radionuclides present exceeds 1.0, the water source is not potable.

12a. If gross alpha analysis in Step 6 is greater than 15 pCi/L, then perform analysis for total

uranium (i.e, total uranium present on a mass basis).

12b. If the total uranium concentration is less than 20 pCi/L (30 :g/L or 30 ppb), and the

corrected gross alpha activity (Gross alpha - total uranium) > 15 pCi/L, go to Step 8 and

begin 226Ra and 228Ra analyses and any other alpha analyses requested by the IC. If the total

uranium concentration is greater than 20 pCi/L, the water source cannot be used as a potable

water supply (Step 16).

13. It is possible that the source may be acceptable for drinking water once radionuclide-specific

analyses are performed. This path has a secondary priority. These samples should be

checked to assess whether or not preservation, using acids or other appropriate chemical, has

been performed. If not preserved, preservation appropriate to the analyte(s) should be made

and the sample stored for potential analysis. Any decision to conduct further analyses or to

dispose sample(s) should be made by the IC.

NOTE: The values in Step 14b correspond to the ADL values in Table 11A of Appendix VI.

Samples that are greater than 6.0×103 14a. pCi/L using the survey meter screening method may

contain naturally occurring radionuclides but will not be potable. Analyze an aliquant of the

sample by gross alpha and beta analysis.

If the results of either the gross alpha or beta analysis1 14b. are greater than the ADLs, the sample

should be preserved for analysis at a later time. It will not be acceptable as a drinking water

source, but more detailed analysis may subsequently be required. If the gross alpha and gross

beta analyses are both less than 110 pCi/L gross " and 410 pCi/L gross $, tritium analysis
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

27

should be performed later (Step 4a of the yellow path).

15. Those samples that exceed the ADLs established for Steps 2a and 2b should be checked for

preservation and stored until all other water sources have been analyzed and found

acceptable or not acceptable. Specific radionuclide analyses may determine that the water

source is acceptable.

16. The water supply is not suitable as a drinking water source. At least one analysis or the sum

of the fractions of the beta emitters has exceeded the MCL for drinking water for that

radionuclide.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

28

1. 

What particle(s) 

are emitted by the

sample

? 2α. 

Alpha only

2β. Beta Only

2μ. 

Multiple

emission modes

9. Report results

to IC

6α1. MQOsTable7A 

5β2.

Other analyses 

as required

3α.

Gross α screen

activity high

? 3β. 

Gross β

screen activity 

high?

3μ. 

Any emitter

screen high

?

α

10. Verify all radionuclides have 

been accounted for; re-evaluate

results, or re-perform

analyses

Yes

5α2.

Other analyses 

as required 

5α1. 

All other SDWA

radionuclide

analyses

No Yes

Yes

Yes

No

No

No

6α2. MQOsScale using

Table 6A 

5μ1. 

All other SDWA

radionuclide

analyses

5β1.

All other SDWA

radionuclide

analyses

6β2. MQOsScale using

Table 6B 

6β1. MQOsTable 7B 

5μ2. 

Other analyses 

As required

6μ1. 

Scale MQOs using

Tables 7A and 7B 

6μ2. 

Scale MQOs using

Tables 6A and 6B 

α, or β or γ

β

7. 

Final results

agree with screening

analyses

?

8.

Sum of fractions

<1.0

?

Yes

4α1.

Alpha-specific

analysis 

>MCL

?

9. Report

to IC

Yes

No

4β1. 

Beta -specific

analyses 

>MCL

?

Yes

9. Report

to IC

4μ1.

Nuclidespecific analyses 

>MCL

?

No

9. Report

to IC

4α2. 

Alpha-specific

analysis

>ADL

?

4β2. 

Beta-specific 

analyses 

> ADL

?

4μ2. 

Nuclidespecific analyses

>ADL

?

Yes

No

No No

No

Water Sample Scenario 3

• Known radionuclides

• Priorities established by Incident Commander

No

Perform α-specific 

analysis

Perform β-specific analysis

Perform nuclide-specific 

analysis

β emissions only

α emissions only

μ Multiple emissions

End result

Key

See accompanying tables 

for alpha and beta/gamma

concentrations, and 

numbered notes

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 – Water Scenario 3 Analytical Flow

VII. RADIOANALYTICAL SCENARIO 3 (Contaminating Radionuclides are Known)
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

29

Notes for Scenario 3: Contaminating Radionuclides Known

Purpose: Support the Specific Needs of the IC

For this scenario, “"” and “$” designate paths to be followed (and their associated notes)

when samples received from the field contain radionuclides that emit only alpha or beta

particles, respectively, and “:” (indicating a mixture of "-, $-, or (-emitting radionuclides)

designates samples that contain either a gamma emitter or multiple emitters (alpha plus

beta).

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 much 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 radionuclides of interest. This allows rapid and more accurate assessment of the

activity before the 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 any two

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(s) that will be used to assess the concentration. Generally, $-only

emitters will be analyzed by GPC or LSC, "-only emitters by either GPC or AS, and $- and

(-emitters by gamma spectrometry. 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 (",

or $, or () path.

2". This path is selected only if all the radionuclides from the event are " 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 radionuclide of interest.

2$. This path is selected only if all the radionuclides from the event are $ 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 radionuclide of interest. If

more than one radionuclide is present, the screening instrument should be calibrated with

the radionuclide that is expected to produce the lowest response. This will provide screening

results that are a more conservative estimate of the activity present for that radionuclide.

2: This path is selected only if the radionuclides from the event emit a combination of ", or $, . or ( emitters. The samples still should be screened to distinguish high from low-activity
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

30

samples. The instrument used to perform the screening analysis should be calibrated with

the radionuclide of interest.

3". The purpose of this step is to distinguish high-activity samples from low-activity 3$. 3:. 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. Using a 1-hour count time as the maximum and

a 10-mL aliquant as the minimum, Table 12 in Appendix VI demonstrates the

capability for MDC and critical-level values that can be achieved routinely using

LSC or GPC analytical methods. Although these MDCs are not equivalent and do

not relate to a specific DWC, they are low enough to be used for screening purposes.

The samples should be numerically ranked based on their gross concentration and

processed according to the priority specified by the IC.

NOTE: The flow of priority splits here. Either of the paths for the suffixes 1 or 2 may get

the priority. The difference is that suffix 1 is for SDWA requirements, and that suffix 2

flow path would be for IC-determined MQOs. Flow path 2 would be scaled to the

appropriate ADL based on the 100-mrem values.

4" The first analytical priority when this path is chosen is for the known contaminant(s) 1 4$1 4:1

from the event. This should use a radionuclide-specific method, and the RDL should

be less than or equal to that shown in Table 7A or 7B. This path would be chosen if

the intent was to look for potable water sources. If the event-specific contaminant is

less than its respective MCL in Table 7A or 7B, then analysis for all other SDWA

contaminants should proceed. If the event-specific contaminant concentration is

greater than its respective MCL in Table 7A or 7B, notify the IC that this is not a

potential potable water source.

4" The first analytical priority when this path is chosen is for the known contaminant 2 4$2 4:2

from the event. This should use a radionuclide-specific method, and the ADL

concentration plus corresponding uMR value should be a multiple of the value found

in Table 6A or 6B (these tables are for the 100-mrem ADLs; the multiple would be

based on the ratio of 100-mrem value to the maximum dose for the particular event).

This path would be chosen if the direction were to identify water sources that may

cause exposure in excess of the maximum dose allowed for the event. If the eventspecific contaminant is less than its respective ADL (based on scaling of concentrations and in Tables 6A or 6B), 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 eventspecific AAL.

5" Perform all other radionuclide SDWA required analyses. 1 5$1 5:1

5" Perform all other event related or requested radionuclide analyses. 2 5$2 5:2

6" Select the MCL values from Tables 7A or 7B to be compared with the final 1 6$1 6:1
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

31

analytical concentrations for the water sample.

6" Select the ADL values from Tables 6A or 6B (scaled to the AAL for the event) to be 2 6$2 6:2

compared with the final analytical concentrations for the water sample.

7. Compare the final results with the screening analysis and verify that no major nuclide has

been missed: the sum of the individual nuclide concentrations (excluding tritium if the

screening measurement was made by GPC) is approximately equivalent to the gross activity

concentration (a rule of thumb is within a range of about half to twice the gross value). 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 RDL or for drinking water), check for errors and resolve any

discrepancies prior to proceeding.

8. If the sum of the fractions of all $- and (-emitting radionuclides present exceeds 1.0, verify

analyses or calculations. The sample would have concentrations that exceed the 40 CFR

limits. If the individual results and the sum of the fractions are less than their respective

limits, report results to IC.

9. Several actions lead to this step:

• In steps 4"1, 4$1, and 4:1, the result for the event-specific radionuclide exceeded the

MCL for the radionuclide in potable water.

• From Step 8, all analyses indicated that the sample is within the limits of the MCLs from

the SDWA.

• In steps 4"2, 4$2, and 4:2, the event-specific radionuclide exceeded the ADL for the

event.

• From Step 10 if the sum of fractions is greater than 1.0.

• From Step 10 if gross activity and sum of individual radionuclide activities in sample do

not match within 0.5 to 2.0.

Notify the IC of the specific final results for all samples, with a description of any

unresolvable discrepancies. All sample residuals or final counting forms should be archived

until notification to dispose of them is received.

10. The results from the radionuclide-specific analysis and the gross measurement should match

to within a factor of 0.5 to 2.0. If they do not, re-analysis may be required starting with the

gross-activity measurement. It is possible that either a short-lived radionuclide activity has

decayed away prior to having been analyzed, or a radionuclide analysis was missed. In either

case, the discrepancy should be resolved, which may include specific correlations for the

radionuclides from this event.

If this step is arrived at as a result of the sum of fractions being greater than 1.0, verify the

data to ensure correctness and that the gross activity and sum of individual activities are

within a factor of 0.5 to 2.0. When this review is completed, notify the IC of results per Step

9.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

32

Appendix I. Tables of Radioanalytical Parameters for Radionuclides of Concern

TABLE 5A – Analytical Decision Levels (ADL) and Required Method Uncertainty

For Gross Alpha Screening Analysis

Radionuclide Half-Life [1]

Additional

Emissions

pCi/L

500-mrem [2] 100 mrem [2]

ADL

Required

Method

Uncertainty [4, 5]

(uMR ) ADL

Required

Method

Uncertainty [4, 5]

(uMR )

Gross " Screen — 1.0×103 6.1×102 200 120

Am-241[3] 432.2 y ( 1.0×103 6.1×102 200 120

Cm-242 162.8 d 7.0×103 4.3×103 1.4×103 8.5×102

Cm-243 29.1 y ( 1.3×103 760 250 150

Cm-244 18.10 y 1.5×103 8.8×102 290 1.8×102

Np-237 2.144×106 y ( 2.0×103 1.2×103 390 2.4×102

Po-210 138.4 d 65 40 13 7.9

Pu-238 87.7 y 900 550 180 110

Pu-239 2.411×104

 y 850 520 170 100

Pu-240 6.564×103

 y 850 520 170 100

Ra-226 1.600×103

 y ( DP 460 280 90 55

Th-228 1.912 y ( DP 1.3×103 790 260 160

Th-230 7.538×104

 y 900 550 180 110

Th-232 1.41×1010 y ( DP 800 490 160 97

U-234 2.455×105

 y ( DP 3.2×103 1.9×103 650 400

U-235 7.038×108

 y ( DP 3.3×103 2.0×103 650 400

U-238 4.468×109

 y ( DP 3.5×103 2.1×103 700 430

Notes:

[1] The half-lives of the nuclides are given in years (y) or days (d). DP refers to “decay products.” Radionuclide above

the gray bar is default for calibrating screening instrumentation.

[2] The values in this table correspond to the numbered rectangles 2 and 7 in Radioanalytical Scenario 1.

[3] The uMR and ADL for 241Am are used for gross alpha screening.

[4] The relative required method uncertainty (nMR) for values greater than the AALs in Table 10A of Appendix VI can

be obtained by dividing the uMR value in this table by the corresponding AAL value in Table 10A.

[5] The individual required method uncertainty (uMR)values in this table apply up to the corresponding values for AALs

or 100-mrem values, respectively, identified in the tables in Appendix VI. Above the values noted in the Appendix

VI tables, the relative required method uncertainty (nMR)would apply. 
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

33

TABLE 5B – Analytical Decision Levels (ADL) For Gross Beta or Gamma Screening Analysis

Radionuclide

Emission

Type Half-Life [1]

pCi/L

500 mrem 100 mrem

ADL

Required

Method

Uncertainty [3, 6]

(uMR )

ADL

Required

Method

Uncertainty [3, 6]

(uMR )

Beta Gamma

Screen[2]

$( 30.07 y 2.9×104 1.8×104 6.0×103 3.6×103

 Sr-90[2] $ ($ DP) 28.79 y 6.0×103 3.6×103 1.2×103 730

 Co-60[2] $( 5.270 y 1.7×104 1.0×104 3.3×103 2.0×103

Ac-227+DP $ (" DP) 21.77 y 550 330 110 67

Ce-141 $( 32.51 d 1.1×105 6.7×104 2.2×104 1.3×104

Ce-144 $( 284.9 d 1.5×104 8.8×103 2.9×103 1.8×103

Co-57 ( 271.1 d 3.2×105 1.9×105 6.5×104 4.0×104

Cs-134 $( 2.065 y 2.2×104 1.3×104 4.3×103 2.6×103

Cs-137 $( 30.07 y 2.9×104 1.8×104 6.0×103 3.6×103

H-3 weak $ 12.32 y 3.9×106 2.3×106 7.5×105 4.6×105

I-125 ( 59.40 d 6.5×103 4.0×103 1.3×103 790

I-129 $( 1.57×107

 y 1.7×103 1.0×103 330 200

I-131 $( 8.021 d 2.7×103 1.6×103

 550 330

Ir-192 $( 73.83 d 6.0×104 3.6×104 1.2×104 7.3×103

Mo-99 $ ( (( DP) 65.94 h 1.6×105 9.7×104 3.2×104 1.9×104

P-32 $ 14.26 d 3.0×104 1.8×104 6.0×103 3.6×103

Pd-103 ( 16.99 d 3.9×105 2.4×105 8.0×104 4.9×104

Pu-241 $ 14.29 y 5.0×104 3.0×104 1.0×104 6.1×103

Ra-228 $ (( DP) 5.75 y 80 49 16 9.7

Ru-103 $( 39.26 d 1.2×105 7.0×104 2.3×104 1.4×104

Ru-106 $( 373.6 d 1.1×104 6.7×103 2.2×103 1.3×103

Se-75 ( 119.8 d 3.4×104 2.0×104 6.5×103 4.0×103

Sr-89 $ 50.53 d 3.2×104 1.9×104 6.5×103 4.0×103

Tc-99 $( 2.11×105 y 1.2×105 7.3×104 2.4×104 1.5×104

Notes:

[1] The half-lives of the nuclides are given in years (y), days (d), or hours (h). DP refers to “decay products.” Radionuclides

above the gray bar are the default radionuclides for calibrating screening instrumentation.

[2] The AAL and associated uMR and ADL values for 137Cs are used for initial beta gamma screening analysis on sample bottle

(Step 1 in Radioanalytical Scenarios 1 and 2). The AAL and associated uMR and ADL values for 60Co concentration are

used for gross gamma measurements thereafter (see text). The AAL and associated uMR and ADL values for 90Sr are the

defaults used gross beta screening. 

[3] The relative required method uncertainty (nMR) for values greater than the AAL values in Table 10B of Appendix VI can

be obtained by dividing the uMR value in this table by the corresponding AAL value in Table 10B.

[4] Several nuclides in Table 5B decay by electron capture. These radionuclides cannot be detected using gross $ analysis.

The electron-capture decay leads to characteristic X-rays of the progeny nuclide. The most effective way to detect the Xrays 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 energy range of these detectors is about 10 keV.

[5] If ( isotopic analysis versus gross ( analysis is used for rectangles 2 and 7 in Radioanalytical Scenario 1, comparisons

should be made to the value specific for the radionuclide found in the ( analysis listed in this table.

[6] The individual required method uncertainty (uMR) values in this table apply up to the corresponding values for AALs or

100-mrem AALs identified in the tables in Appendix VI. Above the values noted in the Appendix VI tables, the relative

required method uncertainty (nMR) applies.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

34

TABLE 6A – Required Method Uncertainties for Alpha-Emitting Radionuclides

 at 100-mrem AAL When Using Radionuclide-Specific Methods

Radionuclide

pCi/L

100-mrem ADL [1]

Required Method

Uncertainty at or Below

100-mrem AAL [2, 3, 4]

uMR

Am-241 280 50

Cm-242 2.0×103 350

Cm-243 350 63

Cm-244 410 73

Np-237 550 98

Po-210 18 3.3

Pu-238 250 45

Pu-239 240 43

Pu-240 240 43

Ra-226 130 23

Th-228 370 65

Th-230 250 45

Th-232 230 40

U-234 920 160

U-235 920 160

U-238 990 180

Notes:

[1] Only the 100-mrem ADL and the associated required method uncertainty (uMR) are shown.

[2] See Appendix VI for the rationale and methodology used in determining these values.

[3] These method uncertainties are applicable to each radionuclide when a radionuclide-specific method is used to

determine the activity result .

[4] The values corresponding to an AAL of 100 mrem were chosen for these tables. These values can be used to

conveniently scale to other project-specific AALs. For example, if a specific project had AALs at 20 mrem (one-fifth

of 100 mrem), the table values can be scaled down simply by dividing the listed values by five. Thus, for an

analytical action level of 20 mrem, the respective values for 210Po would be one fifth the values listed in Table 

10A and this table:

20-mrem AAL = [100-mrem AAL / 5] = [26/5] . 5.2 pCi/L,

20-mrem uMR = [100-mrem uMR / 5] = [3.3/5] . 0.66 pCi/L

and the corresponding 20-mrem ADL would be:

20-mrem ADL = [100-mrem ADL/5] = [18/5] = 3.6

See Appendix VI for details of these calculations.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

35

TABLE 6B – Required Method Uncertainties for Beta- or Gamma-Emitting Radionuclides

at 100-mrem AAL When Using Radionuclide-Specific Methods

Radionuclide

pCi/L

100-mrem ADL [1]

Required Method

Uncertainty at or Below

100-mrem AAL [2, 3, 4]

uMR

Ac-227+DP 160 28

Ce-141 3.1×104 5.5×103

Ce-144 4.1×103 730

Co-57 9.2×104 1.6×104

Co-60 4.7×103 830

Cs-134 6.1×103 1.1×103

Cs-137 8.5×103 1.5×103

H-3 1.1×106 1.9×105

I-125 1.8×103 330

I-129 470 83

I-131 780 140

Ir-192 1.7×104 3.0×103

Mo-99 4.5×104 8.1×103

P-32 8.5×103 1.5×103

Pd-103 1.1×105 2.0×104

Pu-241 1.4×104 2.5×103

Ra-228 23 4.0

Ru-103 3.3×104 5.8×103

Ru-106 3.1×103 550

Se-75 9.2×103 1.6×103

Sr-89 9.2×103 1.6×103

Sr-90 1.7×103 300

Tc-99 3.4×104 6.0×103

Notes:

[1] Only the ADL of 100 mrem and the associated required method uncertainty (uMR) are shown.

[2] See Appendix VI for the rationale and methodology used in determining these values.

[3] These method uncertainties are applicable to each radionuclide when a radionuclide specific method is used to

determine the activity result.

[4] The values corresponding to an AAL of 100 mrem were chosen for these tables and can be used to conveniently

scale to other project-specific AALs. For example, if a specific project had AALs at 20 mrem (one-fifth of 100

mrem), the table values can be scaled down simply by dividing the listed values by five. Thus, for an AAL of 20

mrem, the value for 90Sr would be one-fifth the values listed in Table 10B and this table:

20 mrem AAL = 100 mrem AAL / 5 = [2400/5] = 480 pCi/L

20 mrem uMR = 100 mrem uMR / 5 = [300/5] = 60 pCi/L

and its corresponding ADL would be:

20 mrem ADL = 100 mrem ADL / 5 = [1700 / 5] = 340 pCi/L

See Appendix VI for details of these calculations.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

36

TABLE 7A – Maximum Contaminant Levels (MCL) and Required Detection Levels (RDL)

for Alpha-Emitting Radionuclides in Water

Radionuclide

Drinking Water

MCL [1]

pCi/L (mg/L) [2]

Drinking Water

RDL[5]

pCi/L (mg/L) [2]

Gross " Screen 15 3[4]

Am-241 15 (4.4×10–9) 1.5 (4.4×10–10)

Cm-242 15 (4.5×10–12) 1.5 (4.5×10–13)

Cm-243 15 (3.0×10–10) 1.5 (3.0×10–11)

Cm-244 15 (1.8×10–10) 1.5 (1.8×10–11)

Np-237 15 (2.2×10–5) 1.5 (2.2×10–6)

Po-210 15 (3.3×10–12) 1.5 (3.3×10–13)

Pu-238 15 (8.9×10–10) 1.5 (8.9×10–11)

Pu-239 15 (2.4×10–7) 1.5 (2.4×10–8)

Pu-240 15 (6.6×10–8) 1.5 (6.6×10–9)

Ra-226 [3] 5 (5.1×10–10) 1.0 (1.3×10–10)

Th-228 [3] 15 (1.8×10–11 1.5 (1.8×10–12)

Th-230 15 (7.3×10–7) 1.5 (7.3×10–8)

Th-232 15 (1.4×10–1) 1.5 (1.4×10–2)

U-234 — —

U-235 — —

U-238 20 (3.0×10–2 ) 2.0 (3.0×10–3)

U-Nat 20 (3.0×10–2 ) 2.0 (3.0×10–3)

Notes:

[1] Continuous intake.

[2] Value in parenthesis is mass concentration units, (ppm).

[3] Combined concentration of 228Ra and 226Ra not to exceed 5 pCi/L.

[4] Value for RDL taken from 40 CFR 141.26(a)(2)(iii). See “Final Implementation Guidance for Radionuclides,” EPA

816-F-00-002, March 2002. Available at: www.epa.gov/safewater/radionuclides/compliancehelp.html.

[5] RDL value taken as 1/10 of the MCL value if not otherwise specified in the regulations.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

37

TABLE 7B – Maximum Contaminant Levels (MCL) and Required Detection Levels (RDL)

for Beta/Gamma-Ray Emitting Radionuclides in Drinking Water

Radionuclide

Drinking Water

MCL [1]

pCi/L (mg/L) [2]

Drinking Water

 RDL [6]

pCi/L (mg/L) [2]

Gross $ Screen 50 5.0

Ac-227+DP [4] 15 1.5

Ce-141 300 (1.1×10–11) 30 (1.1×10–12)

Ce-144 29, 30[4] (9.4×10–12) 2.9, 3.0 (9.4×10–13)

Co-57 1,000 (1.2×10–10) 100 (1.2×10–11)

Co-60 100 (8.8×10–11) 10 (8.8×10–12)

Cs-134 80 (6.2×10–11) 10 (7.8×10–12)

Cs-137 200 (2.3×10–9) 20 (2.3×10–10)

H-3 2.0×104

 (N/A) 1,000 (N/A) [7]

I-125 30 (1.7×10–12) 3.0 (1.7×10-13)

I-129 1 (5.7×10–6) 0.1 (5.7×10–7)

I-131 3 (2.4×10–14) 1.0 (8.0×10–15)

 [7]

Ir-192 100 (1.1×10–11) 10 (1.1×10–12)

Mo-99 600 (1.2×10–12)

[5] 60 (1.2×10–13)

P-32 30 (1.0×10–13)

[5] 3.0 (1.0×10–14)

Pd-103 900 (1.2×10–11)

[5] 90 (1.2×10–12)

Pu-241 300 (2.9×10–9)

[5] 30 (2.9×10–10)

Ra-228 [3] 5 (1.8×10–11) 1.0 (3.7×10–12)

[7]

Ru-103 200 (6.2×10–12) 20 (6.2×10–13)

Ru-106 30 (9.1×10–12) 3.0 (9.1×10–13)

Se-75 900 (6.2×10–11) 90 (6.2×10–12)

Sr-89 20 (6.9×10–13) 10 (3.4×10–13) [7]

Sr-90 8 (5.8×10–11) 2.0 (1.4×10–11) [7]

Tc-99 900 (5.3×10–5) 90 (5.3×10–6)

Notes:

[1] Continuous intake.

[2] Value in parenthesis is mass concentration units (ppm).

[3] Combined concentration of 228Ra and 226Ra not to exceed 5 pCi/L.

[4] Includes decay products originating from the 227Ac in the body. Used only to calculate the concentration (pCi/L) or

dose from 227Ac in the body. DP refers to “decay products.”

[5] Value from OSWER Directive 9283.1-14, Appendix B: “Use of Uranium Drinking Water Standards under 40 CFR

141 and 40 CFR 192 as Remediation Goals for Groundwater at CERCLA sites.” November 6, 2001. Available at:

www.epa.gov/superfund/health/contaminants/radiation/pdfs/9283_1_14.pdf.

[6] RDL value taken as 1/10 of the MCL value if not otherwise specified in the regulations.

[7] RDL value taken from “Radionuclides Notice of Data Availability Technical Support Document,”(March 2000).

Available at: www.epa.gov/safewater/rads/tsd.pdf. 40 CFR 141.26(a)(2)(iii). See “Final Implementation Guidance

for Radionuclides,” EPA 816-F-00-002, March 2002. Available at: www.epa.gov/safewater/radionuclides/

compliancehelp.html.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

1

 Depending on the time of the response, a 2-rem PAG may be applicable. If so, the radionuclide concentrations

corresponding to the 2-rem PAG DWC can be calculated by taking the values for the 100-mrem column in the table and

multiplying by 20.

2

 Some manufacturers have developed kits that include the survey meter plus an alpha–beta–gamma pancake GM

detector and a NaI gamma detector.

38

APPENDIX II. Example of High Radionuclide Concentration in Water (Radioanalytical

Scenario 1)

Description

Surface water, storm water, drinking water, and estuaries have been impacted by an RDD. The

specific radionuclides causing the radiological incident have not yet been determined, nor has their

concentration in these samples. The event sequence in the laboratory assumes a single analyst

following the analytical process chart, under conditions of single process stream. Analysis at this

point is to assess if the 500-mrem AAL1

 values are exceeded by measurement of the sample’s total

gross radioactivity with hand-held survey instruments. These might include a survey meter or

Geiger-Muller counter with appropriately calibrated beta and gamma detector probes or a microroentgen meter (gamma only).2

 This step would most likely be performed with the sample container,

unopened, leaving the determination of " AAL values to the next step. Unless the identification of

the radionuclide contamination is known, the hand-held survey instrument should be calibrated to

respond to a gross screening $ and ( concentration of 5.8×104

 pCi/L; a 137Cs calibration source

should be used. If the identity of the radionuclide(s) is known, the ADL for the radionuclide listed

for the 500-mrem value is to be used (see Table 5B, page 33). For survey instruments having an

exposure rate readout, the instruments should be calibrated in terms of pCi/L per exposure unit

readout for each container geometry expected and for the nuclide of interest (137Cs for unidentified

nuclides).

Event Sequence

It is Day 1 of the event. The incident responders have established a field office for coordinating

response efforts, including a laboratory project manager. At 1200 hours of Day 1, the incidentresponse team sends a laboratory three water samples taken from the affected area that they believed

to be significantly above background radiation levels. The samples arrive at the laboratory at Day

1, 1500 hours.

Analysis Path

Laboratory personnel perform an initial scan of the three 1-liter sample containers using a hand-held

survey meter with appropriate detector probe obtaining the data in the table below. The average beta

detection efficiency is 30%, and one may assume that the probe responds only to 10% of the decays

from the sample bottle. Thus, the overall beta-detection efficiency for this scanning technique is

3 %. The overall gamma survey instrument response (a NaI(Tl) detector) conversion factor for this

sample geometry (i.e., the one-liter sample bottle) is 53.6 pCi/(:R/h).
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

39

Container ID Gross Beta, cpm Gross Gamma, :R/h

1 5,100 1,175

2 470 57

3 300 35

Background 300 35

Alpha analysis has not yet been performed on these samples. The sample measurements from the

above table are converted to units comparable to those in Table 6A for Container 1 having a 1-L

volume as follows:

Gross Beta Activity (5100 - 300) cpm

(3.7 10 dps / pCi) 60 s / min 0.03 = 2 72,070 pCi / L × ×× = −

and

Gross Gamma Activity = (1,175-35 :R/h) × ( 53.6 pCi / :R/h) = 61,104 pCi/L.

The gross beta result exceeds the screening ADL of 2.9×104 pCi/L, and the gamma value exceeds

the gross screening gamma ADL for 137Cs in Table 5B (4.1×104

 pCi/L), which take the sample

priority to the flow path for Container 1, Step 2, of Figure 2 (page 13). red

A similar analysis for Container 2 yields 2,552 pCi/L beta and 1,179 pCi/L gamma. This takes us

to the flow path for Container 2 because it is less than the gross screening value of 2.9×104 green

pCi/L. Container 3 is measuring the equivalent of background dose rates, and at this point would be

relegated to the flow path. yellow The time is Day 1, 1600 hrs.

Step 2, Container 1. A 5-mL aliquant of Container 1 is taken for gross alpha/beta analysis by liquid

scintillation counting and gross gamma by Na(I)Tl. The net 15-min count rate for beta is 9.25×102

cpm (corrected for full open window efficiency of 0.60, yields 1.38×105 pCi/L), and for alpha is

1.14×102

 cpm (corrected for full open window efficiency of 0.10, yields 1.02×105). The laboratory

compares the pCi/L values with those in Tables 5A and 5B. The laboratory personnel will find that

both alpha and beta values exceed the maximum ADL concentration listed (241Am for alpha and 90Sr

for beta).

The laboratory notes that the liquid scintillation gross beta counts far exceed the survey instrument

gross beta counts. This indicates the presence of low energy beta emitters that would not be detected

by a survey instrument.

The gross gamma count of 2.65×102

 cpm (corrected for 85% efficiency to 2.8×104 pCi/L) is also

greater than the ADL concentration in Table 5B (1.6×104

 for 60Co). The well NaI(Tl) detector

display indicates the presence of several gamma ray peaks in the spectrum. The sample stays on the

fast track for analysis. (red)

The time is Day 1, 1700 hours.

Step 3, Container 1. The laboratory compares the results of the Step 2 screening analyses with the

500-mrem ADL concentrations for screening in Tables 5A and 5B and determines that ADL

concentrations have been exceeded for Container 1 for all three classes of analytes (", $, and ().
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

40

NOTE: No peak at 661 keV for 137Cs is found. The survey instruments used for screening analysis should

be recalibrated with a gamma emitter that more closely matches the gamma energies of the 214Pb/Bi

radionuclides.

The laboratory manager promptly notifies the IC that initial screening indicates that the 500-mrem

AAL concentrations may have been exceeded for Container 1.

A sub-sample (aliquant) would be taken for each class of analysis (three total). While the digestions

of the sub-samples for alpha (Step 4) and beta (Step 5) specific analyses are being performed, the

third sample will be counted on an HPGe detector for about 1 hour (Step 6) for specific gamma ray

identification.

The gamma spectrum will show net activity in several gamma peaks: 186, 295, 352, 609, 1,120, and

1,764 keV. These gamma peaks will be significantly above detector backgrounds for these energies,

which correspond to 226Ra (and 214Pb/214Bi progeny of 222Rn and 226Ra). This suggests to the analyst

at least that 226Ra is present. Activity estimates for 226Ra can be made from the gamma-spectrometry

data for the 186-keV peak. Due to the diffusion of 222Rn from water, it is expected that equilibrium

between 226Ra and 222Rn (and decay progeny) in the water sample will not be attained. As such, the

226Ra activity estimates from the 226Ra/222Rn progeny photopeaks 295, 352, 609, 1,120, and 1,764

keV will be biased low. However, it will show that the total beta activity does not come from only

the contribution of the radium progeny. The time is Day 1, 1830 hours.

It must be kept in mind that the gamma spectrum has eliminated the possibility of 131I and 137Cs, for

this sample. However, tritium must be analyzed specifically, as its presence cannot be detected with

the initial survey instruments and may be obscured during the gross liquid scintillation analysis due

to the presence of the other beta emitters in high concentrations (see caution about beta mismatch

in the preceding note about Step 2). Thus, an aliquant of the original sample or that used for the

gamma spectrometry should be distilled, and the distillate analyzed for tritium. Sample analysis for

tritium indicates 80,000 pCi/L tritium present at Day 1, 1930 hours.

When the alpha- and beta-specific analyses are completed, only 90Sr at 8,000 pCi/L, 226Ra at 28,000

pCi/L (and their respective progeny) and 3

H at 80,000 pCi/L are found. It is important to note that

the total gamma activity from 226Ra and its decay products is only about 80% of the total beta

activity from these radionuclides. This is due to the low abundance of the gamma rays from this

group of radionuclides.

Step 15, Container 1. These values are reviewed and are within about 25% of predicted from the

gross analysis performed in Step 2. The value for 226Ra exceeds the 500-mrem ADL concentration

of 460 pCi/L, 90Sr value exceeds the 500-mrem ADL concentration of 6.0×103

, and 3H exceeds the

20,000 pCi/L MCL from the SDWA. These results are transmitted to the Incident Command Post.

The time is Day 1, 2030 hours.

The remainder of the original sample is preserved, potentially for future analysis. The analysis of

the container with the next highest priority based on dose would now proceed.

Step 7, Container 2. This container has initial measurements of 470 cpm beta and 57 :R/h gamma
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

1

(470-300)/[(0.03)(2.22) = 2,552 pCi/L beta, (57-35)[53.6 pCi/ (:R/h)] = 1,179 pCi/L gamma

2

The sum of the fractions is calculated as follows using the values from Tables 10A and 10B (Appendix VI) under the

100-mrem level (green) columns (Note that the contribution from " emitters is not included as part of the sum of

fractions.):

Radionuclide

Table 10A

or 10B Value

(pCi/L)

Sample Concentration

From Radioanalytical Scenario

(pCi/L) Fraction 3

H 1.5×106 1.8×103 1.2×10–3

90Sr 2.4×103 3.0×102 1.25×10–1

Sum — — 0.126

41

corresponding to 2,552 pCi/L1

 gross beta and 1,179 pCi/L gross gamma. It will follow the green

flow path from Step 1. The analysis of a 5-mL aliquant for a 15-minute gross alpha/beta count by

liquid scintillation will proceed.

 Step 7 yields a gross alpha value of 2.8×10!1 Steps 8 and 9, Container 2. cpm (corrected for full

open window efficiency of 0.10, yields 2.52×102 pCi/L) and gross beta value of 17 cpm (corrected

for full open window efficiency of 0.60 , yields 2.55×103 pCi/L). These, when compared to the

values in Tables 5A and 5B, verify that the 500-mrem ADL concentrations have not been exceeded,

but the 100-mrem ADL screening values of 2.0×102 pCi/L (based on 241Am) and 1.2×103

 (based on

90Sr) have been exceeded. The time is Day 1, 2100 hours.

Step 10, Container 2. Analysis of alpha, beta, and gamma-specific radionuclides begins. Gamma

spectrometry indicates no gamma rays are present except for those from 226Ra progeny. The time is

Day 1, 2230 hours.

The aliquant from Container 2 is analyzed for tritium directly and found to contain 1800 pCi/L. The

time is Day 1, 2330 hours.

First results from the alpha- and beta-specific analyses are completed. The time is Day 2, 0300

hours.

All alpha- and beta-specific analyses are completed. Supervisory review of results is completed,

identifying the presence of 226Ra (6.3×101

 pCi/L) and 90Sr (3.0×102 pCi/L). The time is Day 2, 1300

hours.

Steps 15 and 16, Container 2. Comparison of the gross alpha and gross beta to the sum of the

alpha- and beta-emitting radionuclides matches to within 30%. None of the individual values of the

identified radionuclides exceed their respective 100-mrem ADL concentration. Nor does the sum

of the fractions of the $- and (-emitting radionuclides (0.126) exceed the aggregate AAL (1.0).2

Thus neither exceeds the 100-mrem level. Results are reported to the Incident Commander. The

remainder of the original sample is preserved for future analysis. The analysis of the container with

the next highest priority (based on dose) would now proceed. The time is Day 2, 1500 hrs.

Step 11, Container 3. Initial micro-R or survey meter screening of this sample resulted in a dose

rate equivalent to background, and the sample aliquants analyzed by LSC also were equivalent to
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

42

background in the short count. Following Step 9 on the decision tree, the gross beta-to-gamma ratio

(Step 11) is calculated for a 10–15-mL aliquant of the sample (dried onto a planchet) and counted

with a hand-held device. (It also would be possible to use the gross count data from the LSC and

gamma spectrometry analyses to compute this value if more convenient for the analyst.) If the ratio

is greater than 2.5, there is a strong possibility that 90Sr is present and that analysis should be

immediately initiated. Due to the low activity in this sample, it is unlikely that it has been affected

by the event, but it is prudent to determine whether if abnormal levels of 90Sr are present. Due to the

low activity in this sample, it is unlikely that it has been affected by the event. It is preserved, and,

if necessary, analysis may be resumed later at Step 12. The time is Day 2, 1600 hours.

Steps 12 and 13, Container 3. A 250-mL aliquant of the sample is counted by GPC to assess the

gross alpha and beta values with respect to the maximum contaminant level (MCL). If gross alpha

or gross beta is greater than 5 or 50 pCi/L, respectively, then the radionuclide-specific analyses

should be performed if deemed necessary by the IC. If both are less than these values, the remainder

of the original sample should be archived for analysis at a later time (Step 17). If this sample is less

than both 5 and 50 pCi/L for alpha and beta, respectively, then it may be suitable as a drinking water

source, and further analysis would be required. The actual gross alpha and beta results are 2 and 5

pCi/L, respectively. The time is Day 2, 1800 hours.

Steps 14 and 15, Container 3. The sample analyses have been completed for all alpha, beta and

gamma emitters. Only traces of strontium above background (0.5 pCi/L) have been detected. The

results are reviewed and transmitted to the IC. The time is Day 2, 2100 hours.

Elapsed time from receipt of samples at laboratory: 30 hours.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

1

The events and radionuclides for Radioanalytical Scenario 2 are unrelated to Radioanalytical Scenario 1.

43

APPENDIX III. Example of Finding a Potable Water Source (Radioanalytical

Scenario 2)

Description1

During the intermediate phase following the detonation of an RDD, sources of potable water will

need to be evaluated for radioactive contamination. For this scenario, the priority switches from the

high priority for high-activity samples (clearly not potable) to high priority for low-activity samples.

Thus, all water samples are screened for gross alpha and beta radioactivity based on the MCL

screening levels, and those samples having gross radioactivity concentrations below the MCL have

priority for specific contaminant analyses. The radionuclide contaminants that initiated the incident

should have been completely characterized by now under “Radioanalytical Scenario 1,” and their

results would lead into the specific radioanalytical processes. However, it is possible that the water

sources may have other radionuclide contaminants, either related to the initial incident or from

naturally occurring sources, which also will need to be characterized. It is important to note that the

priority flow path for this scenario is set up the opposite of Radioanalytical Scenario 1: the high

priority flow path is for those samples that have very low activity. Additionally the flow diagrams

are based on the concept of establishing the MDC as the AAL. Thus, the values for the ADLs are

calculated using Tables 11A and 12 in Appendix VI.

Event Sequence

It is Day 8 following an RDD event. The intermediate phase of the event is ongoing. The Incident

Command Center has dispatched three samples to be assessed for their potential as drinking water

sources for population areas where people will be returning to live.

The time frame for results is not as critical as in Radioanalytical Scenario 1, but prompt identification of drinking water sources is important in rebuilding public confidence in the cleanup effort. The

only radionuclides that have been identified in any of the samples to date are 226Ra (and its progeny),

3

H, and 90Sr. The beta survey meter has been calibrated with a 90Sr-specific source, and an overall

efficiency for a 1 liter sample geometry is found to be 8%. The response of the micro-R meter to a

radium source has been found to be 70 pCi/(:R/h).

The three samples arrive at the laboratory at 0800 on Day 8.

Analysis Path

The three samples are screened upon arrival using a micro-R meter and a beta survey meter, yielding

the following results based on the instrument specific calibrations:

Sample

Container

Container

5

Gross

pCi/L

Container

6

Gross

pCi/L

Container

7

Gross

pCi/L

Instrument

Background

Gross Beta, cpm 2,300 11,261 300 0 300 0 300

:R/h 38 210 36 70 35 0 35
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

44

Container 5 is greater than the 100-mrem ADL concentration for 90Sr (see Table 6B) and is set aside

for analysis at a later date. Containers 6 and 7 are less than any 100 mrem values except for 228Ra.

 The potential radionuclides are 226Ra, 3H, and 90 Steps 2a and 2b, Containers 6 and 7. Sr. An 8-mL

aliquant of each sample is counted for 100 minutes on a gas proportional counter (GPC) with the

following results. (See Appendix VI, Table 12, for approximate counting times. Laboratory

personnel should use specific correction factors from their instruments to determine these times).

Sample

Container

Container

6

Container

7

Reagent Blank

 Background

GPC cpm, alpha 0.04 0.02 0.02

GPC cpm, beta 145 12.3 4.5

Container 6 gross beta result is greater than 10,000 pCi/L, and the high GPC result compared to the

beta screening result indicates a low energy beta emitter. Therefore, it is checked for preservation

requirements and stored for analysis in the near future (next day or two), continuing at Step 13.

Container 7 has a gross beta concentration of 84 pCi/L. This is possibly a potable water source

depending upon the specific radionuclides contained in the sample. An aliquant is removed for

tritium analysis (Step 4a), and will also be assessed using Steps 3, 4b, and 6. It is Day 9, 0900 hours.

Step 4b, Container 7. This analysis from Step 4a should be started prior to taking any other steps.

An assessment of whether or not the ADL for tritium has been exceeded can be determined using

LSC in about 40 minutes. For this sample, the tritium concentration is determined to be 580 pCi/L

(the ADL for the analysis was determined to be 410 pCi/L). This confirms that Steps 3, 5, and 6

should proceed. It is Day 9, 1400 hours.

Steps 3, 5, and 6, Container 7. Due to the low reading on the micro-R or survey meter in Step 1,

a larger sample size was taken for the sample in Step 2b. In order to approximate the RDL values

in the SDWA, the lab selects a sample size commensurate with its normal water quality programs.

Looking ahead to Step 6, the sample follows the path “5–15 pCi/L” to the next step, “Begin

radionuclide-specific alpha analysis” (Step 8). Also, Step 5 divides at the 50 pCi/L level,

significantly above this sample, so the next step is “begin radionuclide-specific beta analyses” (Step

7). Beta-specific and gamma analyses should be performed in parallel.

The alpha- and beta-specific analyses are completed, yielding values for 226Ra of 3.6 pCi/L and for

90Sr of 1.2 pCi/L. It is Day 10, 1200 hours.

Step 9, Container 7. While beta- and alpha-specific analyses are being performed, gamma

spectrometry also should be performed on this sample. Dependent on detector efficiency and sample

size used, the count time will be between about 1 to 4 hours. No gamma-ray emitters are identified

in this sample, except for 214Pb/214Bi. Ra-228 analysis also is performed, and results are 1.1 pCi/L.

It is Day 8, 1800 hours.

Steps 10 and 11, Container 7. The results from Steps 4b, 7, 8, and 9 are checked against the MCL

and for Container 7. All are below the MCLs. The sum of the fractions of the MCLs for all betagamma radionuclides determined (3

H and 90Sr) is 0.179. The value for 226Ra + 228Ra is 4.7 and is less

than the MCL for drinking water. Because these values are less than their respective limits, the water
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

45

may be acceptable as a potable water source. However, the laboratory should continue with all

remaining samples because a single radiologically potable water supply may not be adequate. The

analysis results are sent to the Incident Command Center. It is Day 8, 2300 hours.

Step 13, Container 6. Although this sample had a low overall micro-R or survey meter reading,

it was preserved because of its statistically significant count rate above the reagent blank reading.

The process, based on a time priority, would now pick up with this sample at Steps 4a and 4b.

Step 4a, Container 6. Tritium analysis is started on this sample while preparations are begun for

specific alpha, beta, and gamma spectrometry analysis. Tritium in the sample is measured at 7,780

pCi/L. The time is Day 8, 2400 hours.

Step 3, Container 6. The gross beta value is ~20 pCi/L (Step 5, the majority of the original LSC

response in Step 2 coming from tritium), and the gross alpha value is ~9 pCi/L (Step 8).

Step 5, Container 6. The gross beta concentration is less than 50 pCi/L, so beta-specific and

gamma analyses should be performed (Steps 7 and 9). Gamma spectrometry indicates no other

gamma emitters except for 214Pb/214Bi. Beta analyses indicate the presence of 90Sr at 6.0 pCi/L. The

time is Day 9, 0400 hours.

Steps 6 and 12, Container 6. The gross alpha indicates that it is not necessary to determine if

uranium is present (Steps 12a and b). However, due to the nature of the event, uranium analysis by

inductively coupled plasma-mass spectrometry is performed and subsequently shows that total

uranium to be 2.7 pCi/L. The IC has requested that additional alpha specific analyses should be

performed just to ensure that no other radionuclides are present (Step 8). It is Day 9, 0200 hours.

 Alpha-specific analysis is performed for 226 Step 8, Container 6. Ra and indicates <1.5 pCi/L.

Steps 10 and 11, Container 6. None of the MCLs for the identified radionuclides, or the gross

alpha or beta MCLs, has been exceeded. However, the sum of fractions is 1.139 form tritium and

strontium. Results reported to the Incident Command Center. The time is Day 9, 1000 hours.

Steps 14a and b, Container 5. A 10-mL aliquant is taken from Container 5 for gross alpha and

beta analysis by GPC. After counting, the values are gross alpha 3.88 pCi/L and gross beta 4.6×104

pCi/L. The high LSC beta value compared to the screening analysis indicates a low energy beta

emitter is present. It is Day 9, 1800 hours.

Steps 4a and c, Container 5. LSC is performed on the sample for tritium and found to contain

35,000 pCi/L. As this is above the MCL for tritium, this sample is not suitable for drinking water.

The result is reported to the IC. Other radiochemical analyses would be performed as necessary

based on the requests from the IC.

The time is Day 9, 1900 hours.

Elapsed time from receipt of samples at laboratory: 35 hours.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

1

Radionuclide Scenario 3 is unrelated to either Scenarios 1 or 2.

2

The instrumentation was calibrated previously with a 137Cs source. The new calibration is with a 90Sr source. Because 90Sr will be in equilibrium with its 90Y progeny, the instrument also will measure the 90Y. Any 90Sr dispersed into the

water supply can be assumed to be in equilibrium with its progeny 90Y (72 hours has already passed since the onset of

the event), so the direct beta measurement will be a good approximation of the 90Sr concentration.

46

APPENDIX IV. Radionuclide Contaminants are Known (Radioanalytical Scenario 3)

Description1

A public drinking water supply has been contaminated with a 90Sr source. Major portions of the

supply system have been isolated to prevent the spread of contamination into these portions of the

system. Unlike the two earlier scenarios, the radionuclide is known. For this reason, the screening

methods can be used with greater precision. For this scenario, the IC has decided that the analytical

priority becomes low-activity samples because of a short-term need for reliable potable water

sources. Water samples are screened only for gross beta activity based on the MCL screening levels

for 90Sr. The laboratory has adjusted calibration2

 of its screening survey equipment with 90Sr, making

the gross measurements more accurate. The efficiency with the open-end counter for 90Sr is 18% for

the sample geometry of a 1-L bottle. For this particular laboratory instrument, the 90Sr MCL of 8.0

pCi/L would yield a net (90Sr plus 90Y) beta screen value of (3.2 ± 0.4) cpm. (The uncertainty is for

illustrative purposes only.) Those samples having net beta activity below 3.2 cpm would be

suspected of being below the MCL for 90Sr concentration. The liquid scintillation instrument used

by this laboratory has an overall efficiency for 90Sr in aqueous samples of 86%, and a blank

background of (2.40 ± 0.06) cpm.

The laboratory also has calibrated its gamma survey meter with a 137Cs source yielding 0.017

pCi/cpm for the 1-L bottle. The radionuclide contaminants that initiated the incident should have

been completely characterized using the “Radioanalytical Scenario 1” process. The water supplies

sampled are likely to have radionuclide concentrations over the entire range previously seen from

this event. Although the primary focus is on potable water supplies, it is of secondary importance

to know where the activity is distributed in the water system. Thus, lower-priority samples (i.e., high

activity) will need to be reported to the IC early on and will need to be analyzed eventually.

Event Sequence

It is Day 3 following the dispersal of a large amount of 90Sr into a drinking water supply. The source

of the water in the pipeline is from a reservoir that has been analyzed and found to be

uncontaminated. The intermediate phase of the event is ongoing. The Incident Command Center has

dispatched three samples from different segments of the water distribution system to determine if

these segments have already been contaminated.

The timing for results is as critical as in Radioanalytical Scenario 1 because the public water supply

has been shut down temporarily. Rebuilding public confidence in the cleanup effort will be

enhanced tremendously if portions of the system can be released for use. The three samples arrive

at the laboratory at 0800 hours on Day 3. It is assumed that 90Y is in full equilibrium with the 90Sr

when the samples arrive at the laboratory.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

1

UBGR – LBGR = 210 – 0. uMR = 210/3.29 = 64. ADL = MDC – 1.645 × 64 = 105 cpm.

2

However, additional analyses will need to be done to ensure that MCLs for all radionuclides are met before the water

supply is approved for consumption.

47

Analysis Path

Step 1. The three samples are surveyed upon arrival using a survey meter that has a sliding metal

window. The measurements for the three samples yield the following results for gross beta-gamma:

Sample Number L271 L375 L446 Background

Instrument reading $ + (, cpm 26 ± 3 35 ± 3 85 ± 4 28 ± 3

Instrument reading ( only, cpm 26 ± 2 26 ± 2 29 ± 3 25 ± 2

(Associated uncertainties are 1 sigma.)

The direction from the IC is to assess samples for potential as a source for drinking water. Since the

event-specific radionuclide is known (90Sr, Step 2$), the laboratory personnel use flowchart for

Scenario 3 to get directly to Step 3$. It is Day 3, 0830 hours.

Step 3$1. Sample L271 indicates that it is close to background and apparently has no significant

beta emitters based on the gross screen. A 10-mL aliquot is counted for 60 minutes using the LSC

yielding a value of 100 pCi/L. Using Table 12 in Appendix VI, an MDC for a 10-mL sample and

60 minute count time is 210 pCi/L (this would be adjusted by the laboratory to its specific counting

systems). The ADL for this measurement is 110 pCi/L.1

 Because this result is less than the ADL,

its value is less than the MDC. Proceed to Step 4$1. It is Day 3, 1000 hours.

Both L375 and L446 yield significant beta and gamma count rates, and after Step 4 should be

considered for other analyses if directed by the IC (Step 4$2).

90 Step 4$1. Sr analysis is performed according to Standard Methods Procedure 7500-Sr (see

reference on page 9). The final analytical value determined for 90Sr is (1.95 ± 0.38) pCi/L, with an

MDC of 0.84 pCi/L. Because this is less than the MCL, proceed to Step 5$1.2 It is Day 4, 1400

hours.

 All other SDWA analyses are performed. The only other radionuclide identified is 226 Step 5$1. Ra

at a concentration of (2.6 ± 0.56) pCi/L, with an MDC of 0.90 pCi/L. It is Day 4, 2300 hours.

 The RDL value is 2.0 pCi/L for 90Sr and 1.0 pCi/L for 226Ra. Because 90 Step 6$1. Sr has an MDC

of 0.84 pCi/L, and 226Ra has an MDC of 0.90 pCi/L, MQO requirements for both radionuclides have

been met, and the data are deemed validated.

Step 7. The screening results were basically background. The low concentrations of the two

radionuclides found are consistent with the background reading on the gross scan, and on the gross

LSC analysis (the sum of the 90Sr and 226Ra would yield less than the gross counts background of

28 cpm for the survey meter, and the sum of the 90Sr and 226Ra progeny would yield less than the 100

pCi/L measured with the LSC gross screen).
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

48

Step 8. The sum of the fractions does not need calculation unless tritium or other $ and ( emitters

are found in the sample. Ra-228 analysis will need to be done also to ensure compliance with the

SDWA. [If previous results from this water source are available, this step may be omitted.]

Step 9. The IC is notified that water sample L271 has met the radionuclide requirements of the

SDWA. Gross screening of samples L375 and L446 indicated that they contained high levels of

radionuclides. Request direction as to whether or not detailed analyses on these sources should be

performed.

The time is Day 5, 2400 hours.

Elapsed time from receipt of samples at laboratory: 40 hours.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

49

APPENDIX V. Representative Analytical Processing Times

Samples arrive at lab

Assess survey meter dose rate against

PAGs and field measurements

Perform rapid scan analyses for gross

activities of gamma, beta, and alpha

Sample preservation/preparation for

analysis or temporary storage

Prioritize samples for detailed

analysis for specific radionuclides

Perform radionuclidespecific analysisAssign timeframe, specific analysis,

and refined priority for samples

Assess specific 

results against 

gross analysis

Report positive 

results, maintain

focus on highpriority samples

Report results 

and return to 

lower-priority

samples

Perform radionuclidespecific analysis

Report positive results, 

Investigate source(s) of

discrepancy

Report acceptable

results

Assess specific results

against gross analysis

Acceptable Discrepancy

Comparison with

acceptable results

Discrepancy

Time (Hours)

0

0.25

1.0

1.25

1.5

High Low

3.0

High activity Low activity

6.0

3.5

10 C 20

21 C 24

25 C 30

(plus time for

discrepancies)

4.0

(plus time for

discrepancies)

Figure 5 – Approximate Timeframe for Radiochemical Analyses (Radioanalytical Scenario 1)
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

50

Timeline (Hours)

0.0

1.0

5.0

6.0

7.0

8.5

26

38

39

41

43

46

Samples arrive at lab

Gamma spectrometry

complete

Survey containers for

3× instrument background.

Priority to samples with lowest

activity above background.

Preserve 

and archive

Tritium analysis

complete

Uranium analysis

complete

Beta “hard-to-detects” 

analyses complete

(e.g., Sr-90)

Alpha “hard-to-detects” 

analyses complete

(e.g., Ra-226)

Check specific results against SDWA limits/MCLs

Check specific results against gross analyses

Report unsatisfactory water sources

Report satisfactory water sources

Resolve discrepancies

Note: Analytical priority from here

on to samples < SDWA limits (MCLs).

Work deferred on other samples.

Gross α and β

> 10x reagent blank:

Low priority

Gross α and β

< 10x reagent blank:

High priority

Figure 6 – Approximate Timeframe for Radiochemical Analyses (Radioanalytical Scenario 2)
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

51

Samples arrive at laboratory

Gross screen completed

Gross screen by 

LSC or GPC completed

Gamma spectrometry

analysis screen completed

Gamma spectrometry

analysis for SDWA

requirements

Final report 

to IC

Check AALs > SDWA

requirements

Check SDWA 

requirements

Timeline (Hours)

0.0

0.5 

1.25 

2.5 

3.5 

4.0 

24-30 

30-36 

Final report 

to IC

Figure 7 – Approximate Timeframe for Radiochemical Analyses (Radioanalytical Scenario 3)
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

1 For appropriate samples, AALs and required detection limits are established in Safe Drinking Water Act regulations

(see box 13 in Scenario 1 and boxes 4c, 5, 6, 11, and 12b in Scenario 2).

52

APPENDIX VI. Establishing DQOs and MQOs for Incident Response Analysis

Three distinct radioanalytical scenarios are presented for water potentially contaminated with

radionuclides. The first two assume that the mixture of radionuclides in the sample is unknown. 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 is to support timely decisionmaking by the IC regarding actions to protect human health for the first two cases, and in the third

case to expedite analysis so that suitable drinking water may be used. Specific MQOs are not given

for the third radioanalytical scenario because the analytical action levels (AALs) and decision levels

(DLs) default to the SDWA requirements (see Tables 7A and 7B). The screening analyses in this

scenario are simply used for internal laboratory prioritization.

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: Squares, which

represent activities or tasks; 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 or MCLs. The arrows specify the alternative actions to

be taken.

The DQO process1

 may be applied to all programs involving the collection of environmental data

with objectives that cover decisionmaking activities. When the goal of the study is to support

decisionmaking, 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 8 summarizes the DQO process. From these, MQOs can be established using the guidance in

MARLAP. The information in this table should be sufficient to enable the decisionmaker and

laboratory to determine the appropriate MQOs. The output should include an AAL, discrimination

limit, gray region, null hypothesis, analytical decision level (referred to in MARLAP as “critical

Figure 8 – A Decision Point in

a Flowchart
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

53

Figure 9 – The Data Quality Objectives Process

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 Table 9.

Note that the existence of a decision point diamond implies that Steps 1-4 already have been

determined.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

54

TABLE 8A – 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 decisionmaker.

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

decisionmaking 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 8B.

TABLE 8B – Possible Decision Errors

Decision Made

True Value of the parameter of interest

Greater than the AAL Less than the AAL

Decide that the parameter of interest is

greater than the analytical action level Correct decision Decision Error

Decide that the parameter of interest is

less than the analytical 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. Using values from Table 8D, Figures 10 and 11

illustrate these concepts for case (a) and case (b) respectively. 

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 are defined as the parameters " and $ in steps

6.1 and 6.2 in Table 8C. Values of alpha and beta should be set based on the consequences of

making an incorrect decision. How these are balanced will depend on the AAL, sample loads, and

other factors as specified by the IC.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

55

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 8C – 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 (") 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 (") 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 ($) 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 ($) 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 +

∆

where z1–" and z1–$ are the 1–" and 1–$ 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 Water

56

In Figure 10, the AAL = 100, the DL = 80, ) = 100 – 80 = 20 " = $ = 0.1 and

u . z z

MR ≤

+ = + =

− −

∆

1 1

20

1282 1282

7 8

α β . . .

In Figure 11, the AAL = 100, the DL = 120, ) = 120-100 = 20 " = $ = 0.1 and

u . z z

MR ≤

+ = + =

− −

∆

1 1

20

1282 1282

7 8

α β . . .

Table 8D – Values of z1-" (or z1–$) for

Some Commonly Used Values of " (or $)

" or $ z1-" (or z1–$)

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

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.

Figure 10 – Example Illustrating Case (a).

Baseline Condition (null hypothesis): Parameter

Exceeds the AAL

Figure 11 – Example Illustrating Case (b).

Baseline Condition (null hypothesis): Parameter

Does Not Exceed the AAL

Figures taken from EPA G-4 (2006)
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

57

In the context of analyte detection, the critical value (see MARLAP Attachment 3B.2) 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 analyzed. The

critical value is sometimes called the critical level.

In case (a), the critical value will be UBGR – z1–" 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.

In case (b), the critical value will be LBGR + z1–" 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. This process can be

completed for each diamond in each flowchart to fill in Table 12. In these tables, all values have

been rounded to 2 significant figures.

In the following tables, MQOs were determined for screening using a discrimination level of zero

and Type I and Type II error rates of alpha = beta = 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 alpha = 0.01 with beta = 0.05. This

results in a relative 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.

TABLE 9A – DQOs and MQOs for Radioanalytical Scenario 1. Prioritization Decisions Based on Screening[7]

(Gross ", $, or ( Measurements)

Measurement RectangleDecision Point DiamondType of Analysis, 

", $, or 

(

Analytical AL (pCi/L)Null Hypothesis H0Choose > AAL or < AALi.e., case (a) or case (b)DLDL < AAL in case (a) andDL > AAL in case (b)) = UBGR-LBGR

Type I error rate 

"

Type II error rate

$

uMRnMR[6]RDL or MDCAnalytical Decision Level(Critical Level) (pCi/L)Source of AAL 

1a ([1] 58,000 a 0 58,000 0.05 0.05 18,000 0.30 58,000 29,000 500 mrem 137Cs 

2,7 3,8 " 2,000 a 0 2,000 0.05 0.05 610[2, 3] 0.30 1,000 500 mrem 241Am 

2,7 9 " 400 a 0 400 0.05 0.05 120[3] 0.30 200 100 mrem 241Am 

2,7 3,8 $ 12,000 a 0 12,000 0.05 0.05 3,600[3] 0.30 6,000 500 mrem 90Sr 

2,7 9 $ 2,400 a 0 2,400 0.05 0.05 720[3] 0.30 1200 100 mrem 90Sr 

2,7 3,8 ( 33,000 a 16,500 16,500 0.01 0.05 4,100[3] 0.13 23,000 500 mrem 60Co 

2,7 9 ( 6,600 a 3,300 3,300 0.01 0.05 830[3] 0.13 4,600 100 mrem 60Co 

11[4] a

12 13 " 15 a 3 15 SDWA

12 13 $ 50 a 5 50 SDWA

15[5]

Notes:

[1] Using survey instrument calibrated to 137Cs on contact in the recommended geometry.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

58

[2] u z z MR ≤

+ = + = ≈ − −

∆

1 1

2000

1645 1645

2000

329 610

α β .. .

[3] Diamond 9 is the limiting decision criterion.

[4] Mathematically computed from data obtained earlier.

[5] Based on professional judgment from data obtained earlier. The comparison made is based on the MQOs established

for the screening analyses and the individual radionuclide analyses. The acceptability of this measurement will vary

widely based on the actual radionuclides in the sample and the radionuclides used to calibrate the screening

instruments. Thus it will be incumbent on the laboratory staff to assess the agreement of these numbers. Guidance

given in the document is a ratio range of approximately 0.5 to 2.0.

[6] The value for nMR (relative required method uncertainty) is determined by dividing the value of uMR by the AAL

(fourth column in this table).

[7] Values for gamma analysis assume radionuclide-specific analyses using an HPGe. If a gamma detector of lower

resolution is used, the screening error rates for gamma analysis should be changed to that of the alpha and beta

analysis.

TABLE 9B – DQOs and MQOs for Scenario 1. Values Reported Externally Based on Radionuclide-Specific

Measurements

Measurement RectangleDecision Point Diamond Type of Analysis, 

", $, or 

(

Analytical AL (pCi/L)Null Hypothesis H0Choose > AAL or < AALi.e., case (a) or case (b)DLDL < AAL in case (a) andDL > AAL in case (b)) = UBGR-LBGR

Type I error rate 

"

Type II error rate 

$

uMRnMR[2]RDL or MDCAnalytical Decision Level(Critical Level) (pCi/L)Source of AAL

4 "

See Tables 10A and 10B

a 0.5 AAL 0.5 AAL 0.01 0.05 AL/8 0.13 0.71×AAL[1] 100 mrem AAL 

5 $ a 0.5 AAL 0.5 AAL 0.01 0.05 AL/8 0.13 0.71×AAL 100 mrem AAL 

6 ( a 0.5 AAL 0.5 AAL 0.01 0.05 AL/8 0.13 0.71×AAL 100 mrem AAL 

10 " a 0.5 AAL 0.5 AAL 0.01 0.05 AL/8 0.13 0.71×AAL 100 mrem AAL 

10 $ ( a 0.5 AAL 0.5 AAL 0.01 0.05 AL/8 0.13 0.71×AAL 100 mrem AAL 

14 " a 0.5 AAL 0.5 AAL 0.01 0.05 AL/8 0.13 0.71×AAL 100 mrem AAL 

14 $ ( a 0.5 AAL 0.5 AAL 0.01 0.05 AL/8 0.13 0.71×AAL 100 mrem AAL 

Note:

[1] In case (a), the critical value is UBGR – z1--" uM = AAL – z1–0.01 [)/(z1–0.01 + z1–0.05) ] = AAL – 2.326[ (AAL–0.5

AAL)/(2.326 + 1.645) ]

= AAL – 2.326(AAL / 8) . 0.71 AAL. Specific values for the ADL are listed in Tables 6A or 6B.

[2] The value for nMR (relative required method uncertainty) is determined by dividing the value of uMR by the AAL

(fourth column in this table).
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

59

TABLE 10A – Derived Water Concentrations (DWC) Corresponding to "-Emitting Radionuclide

Analytical Action Levels

Radionuclide Half-Life

Additional

Emissions

pCi/L

500-mrem

AAL

[1] [2]

100-mrem

AAL

[1] [2] [3]

Gross " Screen [5] – – 2.0×103 400

Am-241 432.2 y ( 2.0×103 400

Cm-242 162.8 d 1.4×104 2.8×103

Cm-243 29.1 y ( 2.5×103 500

Cm-244 18.10 y 2.9×103 580

Np-237 [4] 2.144×106

 y ( 3.9×103 780

Po-210 138.4 d 130 26

Pu-238 87.7 y 1.8×103 360

Pu-239 2.411×104

 y 1.7×103 340

Pu-240 6.564×103

 y 1.7×103 340

Ra-226 [4] 1.600×103

 y ( DP 910 180

Th-228 [4] 1.912 y ( DP 2.6×103 520

Th-230 7.538×104

 y 1.8×103 360

Th-232 1.405×1010 y ( DP 1.6×103 320

U-234 2.455×105

 y ( DP 6.3×103 1300

U-235 7.038×108

 y ( DP 6.6×103 1300

U-238 4.468×109

 y ( DP 7.0×103 1.4×103

Notes:

The half-lives of the nuclides are given in years (y) or days (d). DP refers to “decay products.”

[1] Values are based on the dose conversion factors in Federal Guidance Report No.13, CD Supplement, 5-year-old

child and the 50th percentile of water consumption.

[2] 365-day intake.

[3] The-100 mrem AAL values were obtained by dividing 500-mrem PAG DWC values by 5. AALs have been rounded

to 2 significant figures.

[4] Includes decay products originating from the 226Ra or 228Th in the body. Used only to calculate the concentration

(pCi/L) or dose from 226Ra or 228Th in the body.

[5] The AAL and associated uMR and ADL values for 241Am are used as the default for gross alpha screening analysis.
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

60

TABLE 10B – Derived Water Concentrations (DWC) Corresponding to $-Emitting Radionuclide AALs

Radionuclide Emission Type Half-Life

pCi/L

500-mrem

AAL

[1] [2]

100-mrem

AAL

[1] [2] [3]

Beta Gamma

Screen [4] $ – 5.8×104 1.2×104

Ac-227DP $ (" DP) 21.77 y 1.1×103 220

Ce-141 $( 32.51 d 2.2×105 4.4×104

Ce-144 $( 284.9 d 2.9×104 5.8×103

Co-57 ( 271.1 d 6.3×105 1.3×105

Co-60 $( 5.270 y 3.3×104 6.6×103

Cs-134 $( 2.065 y 4.3×104 8.6×103

Cs-137 $( 30.07 y 5.8×104 1.2×104

H-3 weak $ 12.32 y 7.7×106 1.5×106

I-125 ( 59.40 d 1.3×104 2.6×103

I-129 $( 1.57×107 y 3.3×103 660

I-131 $( 8.021 d 5.4×103 1.1×103

Ir-192 $( 73.83 d 1.2×105 2.4×104

Mo-99 $ ( (( DP) 65.94 h 3.2×105 6.4×104

P-32 $ 14.26 d 5.9×104 1.2×104

Pd-103 ( 16.99 d 7.8×105 1.6×105

Pu-241 $ 14.29 y 1.0×105 2.0×104

Ra-228 $ (( DP) 5.75 y 160 32

Ru-103 $( 39.26 d 2.3×105 4.6×104

Ru-106 $( 373.6 d 2.2×104 4.4×103

Se-75 ( 119.8 d 6.7×104 1.3×104

Sr-89 $ 50.53 d 6.3×104 1.3×104

Sr-90 $ 28.79 y 1.2×104 2.4×103

Tc-99 $( 2.11×105 y 2.4×105 4.8×104

Notes:

The half-lives of the nuclides are given in years (y), days (d), or hours (h). DP refers to “decay products.”

[1] Values are based on the dose conversion factors in Federal Guidance Report No.13, CD Supplement, 5-year-old

child and the 50th percentile of water consumption.

[2] 365-day intake.

[3] The 100-mrem AAL values were obtained by dividing 500-mrem PAG DWC values by 5. AALs have been rounded

to 2 significant figures.

[4] The AAL and associated uMR and ADL values for 137Cs are used as the defaults for initial beta gamma screening

analysis on sample bottle (Step 1 in Radioanalytical Scenarios 1 and 2). The AAL and associated uMR and ADL

values for 60Co concentration are used as defaults for gross gamma measurements thereafter (see text). The AAL

and associated uMR and ADL values for 90Sr are the defaults used for gross beta screening. 

Several nuclides in Table 10B decay by electron capture. These radionuclides cannot be detected

using gross $ 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 Water

61

TABLE 11A – DQOs and MQOs for Scenario 2. 

Internal Lab Prioritization Decisions Based on Screening

(Gross ", $, or ( Measurements)

Measurement RectangleDecision Point DiamondType of Analysis, 

", $, or 

(

Analytical AL (pCi/L)Null Hypothesis H0Choose > AAL or < AALi.e. case (a) or case (b)DLDL < AAL in case (a) andDL > AAL in case (b)) = UBGR-LBGR

Type I error rate 

"

Type II error rate

$

uMRnMR[3]RDL or MDCAnalytical Decision Level(Critical Level) (pCi/L)Source of AAL 

1 ([1] 12,000 a 0 12,000 0.05 0.05 3,600 0.30 12,000 6,000 100 mrem 137Cs AAL

2a 2b " 210 a 0 210 0.05 0.05 64 0.30 210 110 LSC MDC 5mL 10

min[2]

2a 2b $ 820 a 0 820 0.05 0.05 250 0.30 820 410 LSC MDC 5mL 10

min[2]

14a 14b " 210 a 0 210 0.05 0.05 64 0.30 210 110 LSC MDC 5mL 10

min[2]

14a 14b $ 820 a 0 820 0.05 0.05 250 0.30 820 410 LSC MDC 5m: 10

min[2]

3 5 $ 50 5 50 SDWA

3 6 " 15 3 15 SDWA

Notes:

[1] Using survey instrument calibrated to 137Cs on contact.

[2] See Table 12.

[3] The value for nMR is determined by dividing the value of uMR by the AAL (fourth column in this table).

TABLE 11B – DQOs and MQOs for Scenario 2.

Values Reported Externally Based on Radionuclide-Specific Measurements

Measurement Rectangle Decision Point DiamondType of Analysis, 

", $, or 

(

Analytical AL (pCi/L)Null Hypothesis H0Choose > AAL or < AALi.e. case (a) or case (b)DLDL < AAL in case (a) andDL > AAL in case (b)) = UBGR-LBGR

Type I error rate 

"

Type II error rate 

$

uMRnMRRDL Analytical Decision Level(Critical Level) (pCi/L)Source of AAL

7 11 $

See Tables 7A

and 7B

See

Tables 7A and 7B

SDWA 

8 11 " SDWA 

9 11 ( SDWA 

4a 4b, 4c 3

H 20,000 1,000 20,000 SDWA

12a 12b U 20[1] 0.3 20 SDWA

Note:

[1] 20 pCi/L = 30 ppb U. The measurement of uranium can be based on mass or activity using appropriate conversion

factors.

Estimates of nominal a priori minimum detectable concentrations (MDC) for two commonly used gross alpha

and beta screening methods, using liquid scintillation and gas proportional counting, have been summarized

in Table 12. The table provides estimates of MDCs as a function of sample aliquant volume and sample
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

1

Currie, Lloyd. 1968. “Limits for Qualitative Detection and Quantitative Determination: Application to Radiochemistry.”

Analytical Chemistry 40(3): 586-593.

62

counting times. The MDCs were calculated using the working expressions provided by Currie1, assuming

paired observations having equal counting times for background and sample measurements and Type I and

II error probabilities of 5%. The table notes provide the typical modern instrument detector efficiencies and

background count rates used to calculate the MDC values. Critical levels (LC) are one-half the MDCs. Liquid Scintillation Counting Emission Type Alpha Alpha Alpha Alpha Alpha Beta Beta Beta Beta Beta Volume (mL) 10 10 10 10 10 10 10 10 10 10 Count Time (m) 1 5 10 30 60 1 5 10 30 60 MDC (pCi/L) 590 210 140 77 53 1,720 730 510 290 210

LC (pCi/L) 295 105 120 38.5 26.5 860 365 255 145 105

Emission Type Alpha Alpha Alpha Alpha Alpha Beta Beta Beta Beta Beta

Volume (mL) 5555555555

Count Time (m) 1 5 10 30 60 1 5 10 30 60

MDC (pCi/L) 880 320 210 110 79 2,760 1,170 820 470 330

LC (pCi/L) 440 160 105 55 39.5 1,380 585 410 235 115

Assumptions for 5-mL sample: alpha detector efficiency = 0.8; alpha background cpm = 1.2; beta detector efficiency = 1.0; betabackground cpm = 36Gas Proportional Counting

Emission Type Alpha Alpha Alpha Alpha Alpha Beta Beta Beta Beta Beta

Volume (mL) 10 10 10 10 10 10 10 10 10 10

Count Time (m) 1 5 10 30 60 1 5 10 30 60

MDC (pCi/L) 1,880 540 330 160 110 1,230 450 300 160 110

LC (pCi/L) 940 270 165 80 55 615 225 150 80 105

Emission Type Alpha Alpha Alpha Alpha Alpha Beta Beta Beta Beta Beta

Volume (mL) 5555555555

Count Time (m) 1 5 10 30 60 1 5 10 30 60

MDC (pCi/L) 3,770 1,080 660 320 210 2,470 900 600 330 230

LC (pCi/L) 1,885 540 330 160 105 1,235 450 300 165 115

Assumptions: alpha detector efficiency = 0.10; alpha background cpm = 0.10; beta detector efficiency = 0.30; beta background cpm = 1.4

TABLE 12 – Minimum Detection Concentration Values for Various Counting Times and Sample Volumes
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance — Radionuclides in Water

63

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 decisionmaker to choose

one of the alternative actions. The analytical action level may be a derived concentration level

(such as the derived water 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).

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.

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.
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64

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 radionuclide concentration (DRC): General application term used in discussions involving

both of the terms derived air concentration and derived water concentration.

derived water concentration (DWC): The concentration of a radionuclide, in pCi/L, 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 related to an analytical action level. In this document, for

example, the “500-mrem DWC for 239Pu” is the concentration of 239Pu, in pCi/L, that would

result in an exposure of 500 mrem and would refer to the 500-mrem PAG. The DWC is

radionuclide-specific.

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 boundaries of the gray region.
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65

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 and 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 estimate of uncertainty before the sample is actually measured. See also uncertainty,

required method uncertainty, and relative required 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.
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66

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

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.
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67

relative required method uncertainty (nMR): The required method uncertainty divided by the

analytical action level. The relative required method uncertainty is applied to radionuclide

concentrations above the analytical action level. A key measurement quality objective.

required method uncertainty (uMR): Method uncertainty at a specified concentration. A key

measurement quality objective. See also relative required method uncertainty.

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 (:R/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.

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.

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 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 water concentration or protective

action guide) is used rather than an analytical decision level.

swipes: 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.
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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.