United States
Department of Energy
United States Environmental
Protection Agency
DOE/EH-0668
EPA 832-R-03-002B
Interagency Steering Committee on
Radiation Standards
Final Report

ISCORS Assessment of Radioactivity in Sewage
Sludge: Recommendations on Management of
Radioactive Materials in Sewage Sludge and Ash
at Publicly Owned Treatment Works
ISCORS Technical Report 2004-04

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This document resulted from interagency discussions.  The Interagency Steering Committee on
Radiation Standards, Sewage Sludge Subcommittee, is composed of representatives from the
Environmental Protection Agency (EPA), Nuclear Regulatory Commission (NRC), Department
of Energy, Department of Defense, State of New Jersey, the city of Cleveland and the county of
Middlesex, New Jersey.  This document has not been approved by the respective agencies and
does not represent the official position of any participating agency at this time.

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ISCORS Assessment of Radioactivity in Sewage
Sludge: Recommendations on Management of
Radioactive Materials in Sewage Sludge and Ash
at Publicly Owned Treatment Works
Developed by the Sewage Sludge Subcommittee
United States
Nuclear
Regulatory
Commission
United States
Department of
Energy
United States
Environmental
Protection
Agency
State of New Jersey
Department of
Environmental
Protection
Middlesex County
Utilities
Authority
Northeast Ohio
Regional
Sewer District
ISCORS Technical Report 2004-04
Date Published: February 2005

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ACKNOWLEDGMENTS

The Sewage Sludge Subcommittee of the Federal Interagency Steering Committee on Radiation
Standards (ISCORS) (1) conducted a survey to collect information concerning radioactive
materials in sewage sludge and ash from Publicly Owned Treatment Works (POTWs),
(2) performed dose modeling to help with the interpretation of the results of the survey, and
(3) developed a guidance on radioactive materials in sewage sludge and ash for POTW owners
and operators. The guidance is based primarily upon the results of the ISCORS survey and dose
modeling.  The following are Sewage Sludge Subcommittee members who actively participated
in the development of the three reports associated with this project:

      Lee Abramson, NRC/Office of Nuclear Regulatory Research
      Kevin Aiello, Middlesex County (New Jersey) Utilities Authority
      James Bachmaier, DOE/Office of Environment, Safety and Health
      Bob Bastian, EPA/Office of Wastewater Management
      Lydia Chang, NRG/Office of Nuclear Material Safety and Safeguards
      Weihsueh Chiu, EPA/Office of Radiation and Indoor Air
      Chris Daily, NRG/Office of Nuclear Regulatory Research
      Mark Doehnert, EPA/Office of Radiation and Indoor Air
      Paula Goode, EPA/Office of Radiation and Indoor Air
      Jenny Goodman, New Jersey Department of Environmental Protection
      Dale Hoffmeyer, EPA/Office of Radiation and Indoor Air
      Rosemary Hogan, NRG/Office of Nuclear Regulatory Research
      Anthony Huffert, NRG/Office of Nuclear Material Safety and Safeguards
      Andrea Jones, NRG/Office of Nuclear Regulatory Research
      Judy Kosovich, DOE/Office of General Counsel
      Tom Lenhart, Northeast Ohio Regional Sewer District
      Jill Lipoti, New Jersey Department of Environmental Protection
      Roy Lovett, Department of Defense
      Tin Mo, NRG/Office of Nuclear Regulatory Research
      Donna Moser, NRG/Region II, Division of Nuclear Materials Safety
      Robert Neel, NRG/Office of Nuclear Material Safety and Safeguards
      Bob Nelson, NRG/Office of Nuclear Material Safety and Safeguards
      Tom Nicholson, NRC/Office of Nuclear Regulatory Research
      Tom O'Brien, NRC/Office of State and Tribal Programs
      William Ott, NRC/Office of Nuclear Regulatory Research
      Hal Peterson, DOE/Office of Environment, Safety and Health
      Alan Rubin, EPA/Office of Science and Technology
      Steve Salomon, NRC/Office of State and Tribal Programs
      Pat Santiago, NRC/Office of Nuclear Material Safety and Safeguards

ISCORS Technical Report 2004-04               iii                           Final, February 2005

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      Dave Saunders, EPA/National Air and Radiation Environmental Laboratory
      Duane Schmidt, NRG/Office of Nuclear Material Safety and Safeguards
      Loren Setlow, EPA/Office of Radiation and Indoor Air
      Behram Shroff, EPA/Office of Radiation and Indoor Air
      Phyllis Sobel, NRG/Office of Nuclear Material Safety and Safeguards
      Scott Telofski, EPA/National Air and Radiation Environmental Laboratory
      Mary Thomas, NRG/Office of Nuclear Regulatory Research
      Mary Wisdom, EPA/National Air and Radiation Environmental Laboratory
      Anthony Wolbarst, EPA/Office of Radiation and Indoor Air
ISCORS Technical Report 2004-04               iv                          Final, February 2005

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PREFACE

The Sewage Sludge Subcommittee of the Interagency Steering Committee on Radiation
Standards (ISCORS) has prepared this report to supplement reports describing the ISCORS
Sewage Sludge Survey and Dose Assessment. This report has not been approved by the
respective agencies and does not necessarily represent the official position of any participating
agency at this time.

The agency contacts on this report are listed below.

U.S. Environmental Protection Agency contact:

       Robert Bastian
       U.S. Environmental Protection Agency - 4204M
       1200 Pennsylvania Avenue, NW
       Washington, DC 20460-0001
       phone:  (202)564-0653
       e-mail:  bastian.robert@epa.gov
U.S. Nuclear Regulatory Commission contact:

       Duane Schmidt
       U.S. Nuclear Regulatory Commission
       Decommissioning Directorate
       MailStopT-7E18
       Washington, DC 20555-0001
       phone:  (301)415-6919
       e-mail:  dws2@nrc.gov
ISCORS Technical Report 2004-04                v                          Final, February 2005

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ABSTRACT

In the United States, there are no identified cases in which radioactive materials in sewage
systems are a threat to the health and safety of POTW workers or the general public. However,
there have been a small number of facilities where elevated levels of man-made radioactive
materials were detected. Based upon this past experience, there is a concern that radioactive
material could concentrate in sewage sludge and ash and could pose a threat to the health and
safety of workers or the public.

As a result of Congressional interest, the Sewage Sludge Subcommittee of the Interagency
Committee on Radiation Standards (ISCORS) conducted a survey of radioactive material in
sewage sludge and ash and performed dose modeling of the survey results to address these
concerns and to estimate typical levels of radioactive materials in POTWs around the country.
The Subcommittee also developed this report for use by POTW operators in evaluating whether
the presence of radioactive materials in sewage sludge or ash could pose a threat to the health
and safety of POTW workers or the general public. The levels of radioactive materials detected
in sewage sludge and ash in the ISCORS  survey indicate that, at most POTWs, radiation
exposure to workers or to the general public, including from land application of sludge for
growing food crops, is very low and consequently, is not likely to be a concern.

The survey obtained sewage sludge and incinerator ash samples from 313 POTWs across the
country.  A total of 45 radionuclides were detected, with 8 radionuclides (Be-7, Bi-214,1-131,
K-40, Pb-212, Pb-214, Ra-226, and Ra-228) reported in more than 200 samples. The highest
concentrations were observed for 1-131, Tl-201, and Sr-89 (all short half-lived medical isotopes).
Many samples contained radium and uranium. The survey results represent a single sampling
event at the 313 POTWs, and therefore, do not account for seasonal or episodic fluctuations in
radionuclide levels. The POTWs participating in this survey were specifically selected for their
potential for finding elevated levels of radioactive materials in their sewage sludge or ash.
Consequently, the survey results should be considered conservative, and may not necessarily
represent typical levels occurring in POTWs across the country.  The dose modeling effort
involving both worker and end use/disposal (including land application)  exposure scenarios
made it clear that while some scenarios and radionuclides give rise to very low doses, there are
other radionuclide-scenario combinations that may be of concern.

Three overall conclusions that arose included the following:  (1) Elevated levels of radioactive
materials were found in some sewage sludge and ash samples, but did not indicate a wide-spread
problem; (2) Estimated doses to potentially exposed individuals are generally well below levels
requiring radiation protection actions; and (3) For limited POTW worker and onsite resident
scenarios, doses above protective standards could occur. This was primarily due to indoor radon
generated as a decay product of naturally occurring radionuclides, such as Ra-226 and Th-228.
This report for POTW owners and operators, which includes a summary of the information
produced by the survey and modeling efforts, is designed to alert POTW authorities to the
possibility of radioactive materials concentrating in sewage sludge and incinerator ash. It was
also intended to inform them how to determine if there are elevated levels of radioactive
materials in their sewage sludge or ash, and to assist them in identifying  actions for reducing
potential radiation exposure from sewage sludge and ash.  A flow chart is provided to assist the
reader in using this report.

ISCORS Technical Report 2004-04                vii                           Final, February 2005

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This report presents recommendations, but not a complete description of all aspects of
environmental or occupational radiation protection.  Chapter 1 describes the meaning of
"elevated levels of radioactive materials" and highlights some examples of concentrated levels of
radionuclides in sludge at various POTWs.  Chapter 2 outlines the purpose of this report.
Chapter 3 identifies the sources of radioactive material that may enter a POTW and describes
potential pathways of human exposure.  Chapter 4 provides an overview of existing regulatory
agency responsibilities regarding radiation protection. Chapter 5 contains recommendations for
the POTW operator in determining whether there is any reason to suspect that elevated levels of
radioactive materials may be present in the POTW, and whether there is any need to sample
sewage sludge or ash for radioactive materials, or monitor air within the POTW for radon.
Chapter 6 contains a process for evaluating sewage sludge or ash sampling and monitoring
results and determining whether any further action by the POTW operator is warranted.
Chapter 7 contains some suggestions for reducing levels of radiation exposure, should the POTW
operator  choose to do so. Various appendices include more detailed information on radiation, on
existing Federal and State radiation protection regulatory agencies along with agency contacts,
and on various analyses that could be used to evaluate levels of radioactive materials detected in
sewage sludge or ash, as well as in indoor air.

This report recommends further actions that may be taken by a POTW operator when elevated
levels of radionuclides are detected. In general, there is no need for further action when
estimated doses, using screening calculations, are below 10 mrem/year. If doses are estimated to
be 10 mrem/year or greater, the POTW operator is advised to consult with its State regulatory
agency to determine if additional analyses should be conducted or if any response actions need to
be considered.  The 10 mrem/year criterion is not a limit, does not include radon, and is not
intended to suggest that higher dose levels are unacceptable.1 It is merely a guide for
determining when advice from radiological specialists should be considered.  This report advises
the POTW operator to contact the State radiation control agency, the Federal Nuclear Regulatory
Commission, the Environmental Protection Agency, or a radiation protection professional, such
as a health physicist, for assistance when designing radiation sampling or monitoring programs,
site-specific surveys, or changes in management practices to reduce radiation exposures.

This report does not constitute rulemaking or formal guidance from any participating agency in
this study.  The recommendations provided result from ISCORS observations while conducting
the ISCORS Survey and Dose Assessment.  Decisions on whether to conduct further nationwide
sludge surveys, develop more detailed technical guidance, or issue  specific regulations
addressing radioactive materials in sewage sludge or ash will be made by the appropriate Federal
or State agencies with legislative authority to address concerns related to radiation protection of
the public and the environment.
1   To place the 10 mrem/year criterion in perspective, the International Commission on Radiological Protection
   (ICRP) has recommended that the acceptable upper limit for public exposure for a member of the public from
   all controllable sources of radiation should be 100 mrem/year. Most Federal and State regulatory agencies have
   also set constraints on individual sources of exposure to the general public that are a fraction of 100 mrem/year,
   and limit occupational exposures to 5 rem/year or less.


ISCORS Technical Report 2004-04                viii                            Final, February 2005

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TABLE OF CONTENTS

ACKNOWLEDGMENTS	iii
PREFACE	v
ABSTRACT	vii
EXECUTIVE SUMMARY	xv
     ES.l  INTRODUCTION	xv
     ES.2  PURPOSE	xvi
     ES.3  WHY IS THERE RADIOACTIVE MATERIAL IN
           SEWAGE SLUDGE AND ASH?	xvii
     ES.4  WHAT ARE THE RELEVANT REGULATORY AGENCIES?	xxi
     ES. 5  WHAT CAN A POTW DO TO
           DETERMINE IF THERE IS RADIOACTIVE CONTAMINATION?
           WHO CAN HELP? 	xxiii
     ES.6  HOW CAN A POTW OPERATOR INTERPRET LEVELS OF
           RADIOACTIVITY DETECTED IN THE PLANT?	xxv
     ES.7  WHAT CAN BE DONE TO REDUCE RADIATION DOSES AND
           RADON LEVELS?	xxviii
1    INTRODUCTION	1-1
     1.1    REPORTED INCIDENCES OF RADIOACTIVE CONTAMINATION	1-2
     1.2    SELECTED EXAMPLES OF CONTAMINATION	1-4
     1.3    CONGRESSIONAL INTEREST	1-8
2    PURPOSE	2-1
3    WHY IS THERE RADIOACTIVE MATERIAL IN SEWAGE SLUDGE AND ASH?
     WHAT IS THE CONCERN?	3-1
     3.1    TYPES OF SOURCES	3-1
           3.1.1  Natural Sources	3-1
           3.1.2  Technologically Enhanced
                Naturally-Occurring Radioactive Materials	3-3
           3.1.3  Man-Made Sources	3-4
     3.2    HOW RADIOACTIVE MATERIALS REACH POTWS	3-4
     3.3    WHY RADIOACTIVE MATERIALS MAY BE OF
           CONCERN AT A POTW	3-10
           3.3.1  Reconcentration of Radioactive Materials at POTWs	3-11
           3.3.2  Radiation Exposure Due to POTW Operations	3-12
           3.3.3  What Are the Average Radiation Doses from All Sources? How Do
                Doses from Sewage Sludge and Ash Compare?	3-16
     3.4    SUMMARY OF RESULTS OF ISCORS SURVEY	3-19
4    WHAT ARE THE RELEVANT REGULATORY AGENCIES?
     WHAT ARE THEY DOING?	4-1
     4.1    U.S. NUCLEAR REGULATORY COMMISSION (NRC) AND AGREEMENT
           STATES	4-2
     4.2    U.S. DEPARTMENT OF ENERGY (DOE)	4-3
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     4.3   U.S. ENVIRONMENTAL PROTECTION AGENCY (EPA)	4-3
           4.3.1  Role in Regulating Facilities That May Discharge toPOTWs	4-3
           4.3.2  Role in Regulating Radon and Indoor Air	4-5
           4.3.3  Role in Regulating POTWs	4-5
     4.4   OCCUPATIONAL SAFETY AND
           HEALTH ADMINISTRATION (OSHA)	4-7
     4.5   INTERAGENCY STEERING COMMITTEE ON
           RADIATION STANDARDS (ISCORS)	4-7
     4.6   STATE AGENCIES	4-8
     4.7   LOCAL AUTHORITIES	4-9
5    WHAT CAN A POTW OPERATOR DO TO DETERMINE IF THERE IS
     RADIOACTIVE CONTAMINATION? WHO CAN HELP?	5-1
     5.1   DETERMINE WHAT RADIOACTIVE MATERIALS MAY BE
           DISCHARGED INTO OR OTHERWISE ENTER THE
           WASTEWATER COLLECTION AND TREATMENT SYSTEM	5-1
     5.2   DETERMINE IF MONITORING OR SAMPLING FOR RADIOACTIVE
           MATERIAL AT THE POTW SHOULD BE PERFORMED	5-2
     5.3   HOW CAN A POTW OPERATOR SAMPLE AND ANALYZE
           SEWAGE SLUDGE AND ASH OR MONITOR FOR RADON?	5-4
6    HOW CAN A POTW OPERATOR INTERPRET LEVELS OF
     RADIOACTIVITY DETECTED IN THE PLANT?	6-1
     6.1   ESTIMATE POTENTIAL DOSES FROM
           RADIOACTIVE MATERIAL IN
           SEWAGE SLUDGE AND ASH THROUGH
           SCREENING CALCULATIONS	6-2
           6.1.1  Compare Estimated Doses to Existing Standards	6-2
           6.1.2  Estimating POTW Worker Radiation Dose	6-4
           6.1.3  Estimating Radiation Dose Due to
                 Use or Disposal of Sewage Sludge and Ash	6-6
           6.1.4  Interpretation of Measured Radon in Air	6-13
     6.2   RECOMMENDATIONS ON EVALUATING ESTIMATED DOSES
           DERIVED FROM SCREENING CALCULATIONS	6-14
     6.3   CONDUCT A SITE-SPECIFIC EVALUATION THAT MAY INVOLVE
           ADDITIONAL SURVEYS OR SAMPLING OF THE POTW,
           POTW PERSONNEL, AND/OR USE OR DISPOSAL SITES	6-15
           6.3.1  Evaluate Any Potential External Radiation Exposure of
                 Collection System Workers or POTW Personnel	6-15
           6.3.2  Evaluate Any Potential External Radiation Exposure of
                 Sludge Management Workers or the General Public	6-17
           6.3.3  How to Evaluate Any
                 Potential Radiation Exposure within the POTW	6-18
7    WHAT CAN BE DONE TO REDUCE
     RADIATION DOSES AND RADON LEVELS?	7-1
     7.1   CONTACT REGULATORY AGENCIES FOR ASSISTANCE	7-1
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      7.2   CONTROLLING SOURCES OF
           RADIONUCLIDES ENTERING THE POTW	7-1
      7.3   REDUCING EXPOSURE TO RADIOACTIVITY FROM SLUDGE	7-3
           7.3.1  Reducing Exposure at the POTW	7-3
           7.3.2  Reducing Exposure Outside the POTW	7-4
      7.4   CORRECTIVE ACTIONS FOR CONTAMINATED AREAS	7-5
8     COMMENTS OR QUESTIONS ON THIS REPORT	8-1
9     REFERENCES	9-1
APPENDICES

A     FUNDAMENTALS OF RADIATION	A-l
B     NRC AND EPA REGIONAL OFFICES BY
      STATE AND IDENTIFICATION OF NRC AGREEMENT STATES	B-l
C     NRC REGIONAL OFFICES	C-l
D     EPA REGIONAL OFFICES	D-l
E     STATE AGENCIES FOR RADIATION CONTROL (AS OF OCTOBER 1, 2004)	E-l
F     EXAMPLES OF POTWS THAT HAVE
      RADIONUCLIDE MATERIALS PROGRAMS	F-l
G     GLOSSARY AND ACRONYMS	G-l
H     SOURCES OF ADDITIONAL INFORMATION	H-l
I     ADDITIONAL INFORMATION ON
      NRC AND AGREEMENT STATE LICENSING AND ENFORCEMENT	I-1
J     RADIOLOGICAL ANALYSIS LABORATORIES	J-l
L     ANALYSIS OF ISCORS SURVEY AND DOSE ASSESSMENT RESULTS	K-l
TABLES

ES.l   Average Annual Exposure to Radiation	xix
ES.2   Calculated Total Peak Dose (Total Effective Dose Equivalent, or TEDE)
      (mrem/year) from Survey Samples: Summary Results for
      95th-Percentile Sample With and Without Indoor Radon Contribution	xx
1.1    Sewage Treatment Plants Where
      Elevated Levels of Radioactive Material Were Found	1-3
3.1    Sources and Potential Pathways for Radioactive Materials to Reach POTWs	3-5
3.2    Types of NRC and Agreement State Licensees and Typical Radionuclides	3-10
3.3    Summary of Concentrations of Radioactivity in Sewage Sludge and Ash from
      AMSA Survey and ISCORS Survey (pCi/g)	3-13
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3.4    Survey Concentration Ranges and Typical U.S. Background Concentrations of
       Radionuclides in Soil, Fertilizer, and Common Building Materials
       (All values are in pCi/g-dry weight)	3-14
3.5    Average Annual Exposure to Radiation	3-17
3.6    Calculated Total Peak Dose from Survey Samples:
       Summary Results With and Without Indoor Radon  Contribution (mrem/year)	3-22
6.1    What are the Existing Standards for Protection of
       Human Health from Exposure to Hazards Such as
       Ionizing Radiation and Radioactivity?	6-3
6.2    Reference Values for Screening Calculation for
       Non-Radon Pathways for Screening Calculation A	6-5
6.3    Indoor Radon Working Levels and pCi/Liter Concentration per
       Unit Sludge Concentration for Screening Calculation A	6-6
6.4    Indoor Radon Working levels and pCi/Liter Concentration per
       Unit (pCi/g) Sludge Concentration for Screening Calculation A	6-6
6.5    Reference Values for Screening Calculations B and C	6-8
6.6    Agricultural Application Non-Radon DSR (mrem/y per pCi/g) Values for
       Screening Calculation C	6-10
6.7    Sludge Application Worker Non-Radon DSR Values (mrem/y per pCi/g) for
       Screening Calculation C	6-11
6.8    Land Reclamation, Landfill, and Incinerator Scenario DSR Values
       (mrem/y per pCi/g) for  Screening Calculation C	6-12
6.9    Indoor Radon Working Level Concentration per
       Unit Sludge Concentration for Screening Calculation C (WL per pCi/g)	6-13
6.10   Indoor Radon Concentrations per
       Unit Sludge Concentration for Screening Calculation C (pCi/L per pCi/g)	6-13
A.I    Radionuclides Included in the ISCORS Dose Assessment (ISCORS 2003)	A-3
A.2    Primary Pathways of Radiation Exposure atPOTWs	A-7
C.I    NRC Regional Offices	C-l
D.I    EPA Radiation Program Managers (As of 6/10/2004)	D-l
L.I    Radionuclides that May be of Concern for Onsite Resident	L-4
L.2    Radionuclides that May be of Concern for Worker Loading	L-4
L.3    Radionuclides Most Likely to be Detected, Greater than 4 pCi/g for the
       95th Percentile Concentration and High Percent of Samples	L-5
L.4    Radionuclides Somewhat Likely to be Detected, 95th Percentile Concentration
       >ND and<4pCi/g, and Percent Samples Generally Low	L-6
L.5    Radionuclides Least Likely to be Detected,  No Detect (ND) for the
       95th Percentile and 4 or Less Percent of Samples Detected,
       Ranked in Decreasing Order of Maximum Concentration	L-7
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FIGURES

ES. 1  Flowchart for ISCORS Recommendations on
      Radioactive Materials in Sewage Sludge and Ash	xxvi
3.1   Average Indoor-Air, Screening-Level Concentrations of
      Radon in the United States (from EPA 1993a)	3-2
3.2   Primary Pathways for Radiation Exposure duetoPOTW Operations	3-15
3.3   Uranium Deposits in the United States. Reference DOE (1977)	3-18
3.4   Major Phosphate Deposits in the United States with Significant Uranium Content	3-18
A.I   Uranium (238U) Decay Series	A-4
A.2   Actinium (235U) Decay Series	A-4
A.3   Thorium (232Th) Decay  Series	A-5
B.I   Delineation of the NRC and EPA Regions	B-l
B.2   Delineation of NRC Agreement States as of October 2004	B-2

BOXES

ES.l  Example of
      Naturally Occurring Radioactive Material Concentrating in Sewage Sludge	xvi
1.1   Recent Example of Radioactive Material Concentrating in Sewage Sludge	1-2
1.2   Elevated Levels of Radioactive Material	1-2
3.1   Sources of Radioactivity	3-1
4.1   EPA Authority	4-4
5.1   Typical Analysis Costs	5-6
6.1   Screening Calculation A:  POTW Workers	6-4
6.2   Screening Calculations: Non-POTWUpper-Bound	6-7
6.3   Screening Calculation C: Non-POTW Scenarios	6-9
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EXECUTIVE SUMMARY

ES.1  INTRODUCTION

Authorities that operate Publicly Owned Treatment Works (POTWs) have many areas of concern
to address in the monitoring and daily operation of wastewater treatment plants.  One of these is
the potential for radioactive materials to become concentrated in the sewage sludge or ash
produced by the treatment plant. Radioactive materials are typically not a major concern at
POTWs; however, they are a component of the waste stream that is not well understood by
POTW operators. A final draft of this report and associated dose modeling report were
published for public comment on November 26, 2003 (68 FR 66503). Changes have been made
to address comments received. This executive summary describes in brief the information
provided in the main body of this report in Chapters 1-7 to follow. The reader is referred to
those chapters for more detail than provided here.

The Nuclear Regulatory Commission (NRC) estimates that of the more than 22,000 regulated
users of Atomic Energy Act (AEA) radioactive materials, about 9,000 users have the potential to
release radioactive materials to sanitary sewer systems. In its 1994 report, Nuclear Regulation:
Action Needed to Control Radioactive Contamination at Sewage Treatment Plants, the General
Accounting Office (GAO) (renamed in 2004 as Government Accountability Office) described
nine cases where contamination was found in sewage sludge or ash or the wastewater collection
system, which have resulted in considerable cleanup expense to the POTW authority or specific
industrial dischargers of wastewater to the POTW  (GAO, 1994). There have been a few
additional cases of radioactive materials detected in sludge that are still under investigation.
Naturally Occurring Radioactive Materials (NORM) may also enter the sewer systems.
(See Box 1.1.)  In some situations, these radioactive materials may enter the wastewater
treatment system and become concentrated in sewage sludge and ash. Previous sampling studies
were limited in scope, but indicated that the following four radionuclides were most frequently
reported in sewage sludge: iodine-131, radium-226, americium-241, and cesium-137. At the
present time, there are no specific Federal regulations that limit the levels of radioactive material
in sewage sludge and ash, although NRC and the Department of Energy (DOE) have
requirements (NRC's 10 CFR Part 20.2003, Disposal by Release into Sanitary Sewage, and
DOE's Order DOE 5400.5, Radiation Protection of the Public and the Environment) that control
discharges to municipal sanitary sewer systems.
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 Box ES.l     Example of Naturally Occurring Radioactive Material Concentrating in
               Sewage Sludge
 There are certain geographical areas of the United States where relatively high radium
 concentrations occur in ground water.  Many public drinking water supplies depend upon
 ground water as their source of water, and some of these supplies have radium levels that
 exceed the drinking water standard for radioactive material. In treating these water supplies to
 remove the radium, a waste stream containing the removed radium may be created. If this
 waste stream is discharged to the sanitary sewer, the radium can be reconcentrated in the
 sewage sludge produced by the POTW. In some cases, the treated sewage sludge with
 elevated levels of radium is used as an organic soil conditioner or fertilizer by farmers and the
 general public. Several States have been aware of such situations and are in the process of
 evaluating the radium levels in these materials.
ES.2  PURPOSE

The NRC, EPA, and other agencies, in coordination with the Office of Science and Technology
Policy (OSTP) and Office of Management and Budget (OMB), formed the Interagency Steering
Committee on Radiation Standards (ISCORS) in 1995.  ISCORS was created to address a need
identified by the GAO and members of Congress related to inconsistencies, gaps, and overlaps in
(then-) current radiation protection standards programs. In addition to NRC and EPA, ISCORS
membership also includes senior managers from the Department of Defense (DOD), the
Department of Energy (DOE), the Department of Labor's Occupational Safety and Health
Administration (OSHA), the Department of Homeland Security (DHS), the Department of
Transportation (DOT), and the Department of Health and Human Services (HHS).
Representatives of OMB, OSTP, and the States are observers at meetings.  ISCORS formed a
Sewage Sludge Subcommittee (Subcommittee) to conduct the ISCORS sewage sludge and ash
survey and to develop this POTW report.

Most of the information previously available on reconcentrating of radionuclides in sewage
sludge and ash was due to unusual circumstances that triggered discovery of incidents in the
course of other POTW operations.  To better understand the occurrence of radionuclides in
sewage sludge and ash, the Subcommittee conducted a survey to determine typical levels of
radioactive materials in POTWs around the country, and performed dose modeling of the survey
results.  (See http://www.iscors.org/library.htm for the full survey report.)  The survey,  which
included samples from POTWs with the greatest potential for elevated levels of radioactive
materials, was undertaken by the Subcommittee to provide an estimate of radioactive materials
that may be found in municipal sewage sludge and ash. The survey results indicated that the
majority of samples with elevated radioactivity were attributable to naturally occurring
radioactive materials rather than man-made sources.  The levels of radioactivity detected in
sewage sludge and ash in the ISCORS survey indicate that, at most POTWs, radiation exposure
to workers or to the general public, including from land application of sludge for growing food
crops, is very low and consequently, is not likely to be a concern. The dose modeling conducted
by ISCORS suggests that the greatest potential for concern involves potential exposures of
certain POTW workers and occupants of buildings constructed on long-term land application
sites (see http://www.iscors.org/library.htm for the full dose modeling report).

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ISCORS developed this recommendations report for use by POTW operators to evaluate whether
the presence of radioactive materials in sewage sludge or ash could pose a threat to the health
and safety of POTW workers or the general public.  Based upon the information produced by the
ISCORS survey and dose modeling efforts, this report has three major purposes:  (1) to alert
POTW operators and State and Federal regulators to the possibility of radioactive materials
concentrating in sewage sludge and incinerator ash; (2) to inform POTW operators how to
determine if, indeed, there are elevated levels of radioactivity in their sewage sludge and ash; and
(3) to assist POTW operators in identifying actions for reducing potential radiation exposure
from sewage sludge and ash.

ES.3  WHY IS THERE RADIOACTIVE MATERIAL IN SEWAGE SLUDGE
       AND ASH?

Radioactive materials are an ever-present component of the natural environment and are also
produced through some human activities. Generally, the presence of radioactive materials is a
concern only when concentrations become sufficiently elevated above background levels to pose
a potential health risk or in cases where the ability of a POTW to use or dispose of the  sewage
sludge or ash is inhibited. There have not been many known occurrences of such elevated
concentrations of radioactive materials in sewage sludge and ash since the 1980s.

There are three general sources of radionuclides in the environment that may enter sewage
treatment systems: (1) natural sources, (2) natural sources concentrated or enhanced by human
activity, and (3) man-made sources. The first of these sources,  natural sources of radiation,
include geologic formations and soils that contain uranium, radium, thorium, radon, and other
nuclides that are radioactive.  Water originating in or moving through these formations and soils
may transport the radioactive materials either dissolved in the water itself, or attached to
suspended solids in the water.  Radon also is released to the atmosphere from soil and water and
can enter any building, including POTW facilities, through ground contact openings in a
concrete slab or foundation wall. The general advice EPA has provided to the public is that all
homes, schools, and Federal workplaces be tested for radon.  That advice also should be
applicable to POTWs. Computerized maps are available that show counties with high  radon
concentrations that may be correlated with the location of a POTW. In addition, POTW
operators should contact their State Radiation Control Program or the State  Drinking Water
Program for information specific to the area served by the POTW.

Levels of naturally-occurring radioactive materials can be enhanced by human activity  and by
technologies associated with extraction processes.  These materials, when enhanced by human
activity, are a second general  source of radionuclides in the environment known as
Technologically-Enhanced Naturally Occurring Radioactive Materials (TENORM).  TENORM
may be introduced to the sewage system from ground and surface water, plants and food, as well
as from potential industrial discharges (e.g., water treatment plants, mining  and petroleum
industries, fertilizers, electronics, ceramics, foundries and paper/pulp mills).

Man-made sources represent a third general source of radionuclides.  These include materials
produced for and as a result of the operation of nuclear reactors and fuel cycle facilities. Other
man-made sources are produced from the operation of accelerators, industrial activities,
scientific research, and medical applications.  Man-made radionuclides may also be present in

ISCORS Technical Report 2004-04                xvii                          Final, February 2005

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the environment due to accidents or fallout from weapons testing.  These materials typically are
considered to be part of background.  NRC and Agreement States have licensed approximately
22,000 facilities to use radioactive materials and approximately 9,000 of these have the potential
to release radioactivity to sanitary sewer systems. Nuclear power plants and nuclear fuel cycle
facilities are not considered significant sources of radioactive materials in POTWs because
almost all of these facilities maintain their own sewage treatment systems that are not directly
connected to the POTWs. It is estimated that only 20% of NRC and Agreement State licensees
actually discharge to the  sewer system.  For example, man-made radioactive materials used in
the diagnosis and treatment of medical conditions are discharged to POTWs when excreted by
human patients at licensed medical facilities and from homes and workplaces after the patient is
released.

Radioactive materials reach POTWs by various sources and pathways other than wastewater
discharges. Infiltration and inflow into sanitary sewers may contain radioactive materials.
Radioactive material can also enter a POTW in chemicals and other materials used in wastewater
treatment and sludge processing. Although it is unlikely that radionuclide levels in sewage
sludges and ash at most POTWs across the country pose a concern for treatment plant workers or
the general public, it is possible that radioactive material from natural and man-made sources
could become concentrated in sewage sludge and ash produced by some POTWs. This could
interfere with some POTW operations, including cost effective use or disposal of sewage sludge
and ash. However, there are low amounts of radioactive materials, legally authorized under
Federal and State laws and regulations, which can be disposed into the sanitary sewer system by
NRC and Agreement State licensees.

Although there is a potential for radioactive materials to reconcentrate in the sewage sludges or
ash produced by POTWs, there have only been limited surveys conducted addressing the
radionuclide levels in sewage sludge or sludge products. A survey conducted by the Association
of Metropolitan Sewerage Agencies (AMSA) as well as the ISCORS survey revealed the
presence of both man-made radioactive material and NORM or TENORM at low levels in
sewage sludges and ash.  Based on what is  known about the potential for reconcentrating
radioactive material at POTWs, the three primary pathways for POTW workers and members of
the public to be exposed to radiation from POTW operations include inhalation, ingestion, and
direct exposure.

Human exposure to radiation sources (Table ES.l) is derived primarily from background natural
radiation; however, a person's occupation,  geographic location, time spent outdoors, need for
diagnostic medical treatments and testing, time spent traveling in airplanes, and other activities
can greatly impact the relative contributions of natural, man-made, and global fallout sources.
On the average, 80% of human  exposure to radiation comes from natural sources: radon gas,
radionuclides in the human body, radiation coming from outer space, and that present in rocks
and soil. The remaining  20% comes from man-made radiation sources, primarily X-rays.
Radiation doses at POTWs are generally insignificant  compared to background radiation under
most conditions. However, under conditions at POTWs where elevated levels of radionuclides
have been detected, there is the possibility that doses to POTW workers and to the general public
could be of concern.
ISCORS Technical Report 2004-04                xviii                          Final, February 2005

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Table ES.1   Average Annual Exposure to Radiation
Source of Radiation
Average
Exposure
(mrem/yr)
Typical Range of
Variability
(mrem/yr)
Natural Sources
Terrestrial
Radon
Cosmic
Internal
30
200
30
40
10-80
30-820
30-80
20-100
Man-Made Sources
Medical
Consumer products
Other (Nuclear fuel cycle and occupational)
Total
50
10
1
360



90-1080
Sources: NCRP 1987a, for average exposure values; Huffert et al. 1994; and Fisher 2003 for ranges of variability.
The ISCORS Survey results provide an estimate of the range of concentrations of radionuclides
that may be present in sewage sludge and ash.  The ISCORS Dose Assessment project provides a
means for estimating potential doses associated with these levels of radionuclides under various
sludge management scenarios (see Table ES.2). The dose modeling results combined with the
Survey measurements make it clear that while most scenarios and radionuclides give rise to very
low doses, there are other radionuclide-scenario combinations that may be of concern (for
example, see onsite resident scenarios for 50- and 100-years of application described in
Chapter 6 and summarized in Table ES.2).
ISCORS Technical Report 2004-04
xix
Final, February 2005

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Table ES.2  Calculated Total Peak Dose (Total Effective Dose Equivalent, or
            TEDE) (mrem/year) from Survey Samples: Summary Results for
            95th-Percentile Sample With and Without Indoor Radon Contribution
Scenario
Sl-Onsite Resident
S2-Recreational User
S3-Nearby Town
S4-Landfill
S5-Incinerator
S6-Sludge
Application Worker
S7-POTW Workers
Subscenario
1 yr of sludge
application
5 years application
20 years application
50 years application
100 years application
N/A
1 yr of sludge
application
5 years application
20 years application
50 years application
100 years application
MSW — Sludge
MSW — Ash
Impoundment
N/A
1 yr of sludge
application
5 years application
20 years application
50 years application
100 years application
Sampling
(mrem/sample)
Transport (mrem/hr)
Loading
TEDE
O
14
55
130
260
0.22
3.2e-03
0.014
0.045
0.094
0.17
0.027
0.041
1.2
7.7
0.15
0.77
3
7.4
15
4.9e-07
1.9e-04
17-70§
TEDE
w/o Rn
1
4.9
16
37
69
-
—
-
-
-
-
0.01
0.014
0.36
-
—
-
-
-
-
—
5.6e-05
13
Dominant Radionuclide(s)
[pathways]
Ra-226 [indoor radon]*
Ra-226 [indoor radon]*
Ra-226 [indoor radon]*
Ra-226 [indoor radon]*
Ra-226 [indoor radon]*
Ra-226 [external]
Ra-226 [outdoor radon]
Ra-226 [outdoor radon]
Ra-226 [outdoor radon]
Ra-226 [outdoor radon]
Ra-226 [outdoor radon]
Ra-226 [indoor radon]*
Ra-226 [indoor radon]*
Ra-226 [indoor radon]*
multiple [multiple]
Ra-226 [external]
Ra-226 [external]
Ra-226 [external]
Ra-226 [external]
Ra-226 [external]
Ra-226 [external]
Th-228
[indoor radon, external]*
Ra-226, Th-228
[indoor radon]*
Notes:
All values rounded to two significant figures. DSRs of 95% are used in all total peak dose calculations. The
symbol "-" denotes that indoor radon was not separately calculated. N/A denotes Not Applicable. MSW denotes
Municipal Solid Waste. TEDE means Total Effective Dose Equivalent.
* The dominant radionuclide applies to doses that include radon. However, radon is typically controlled by
concentration level (e.g., pCi/L or WL) and not by dose. The recommendations in Chapter 6 of this report
use EPA's radon guidelines (4 pCi/L or 0.02 WL) as a metric for actions relating to indoor radon.
§ Range represents results from nine combinations of air exchange and room height (see Section 4.7.3 of
ISCORS 2004-03).
ISCORS Technical Report 2004-04
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The basic conclusions of the ISCORS Survey and Dose Assessment effort, which are considered
somewhat conservative case situations, are as follows:

•  None of the non-POTW scenarios shows a significant current widespread threat to public
   health.

•  If agricultural land application is carried out for a long time into the future, then the potential
   exists for future radiation exposure primarily due to radon, if the land application site is
   converted to residential use.

•  In specific cases of very high concentrations of radioactive materials (e.g., levels above the
   95 percentile), there is the potential for localized radiation exposure.

•  Within the POTW, little exposure is expected.  Only when workers are in poorly ventilated
   areas with large quantities of sludge (e.g., for storage or loading) is there the potential for
   significant exposure, predominantly due to radon.

•  Higher doses are generally attributable to the indoor radon pathway. Both for the Onsite
   Resident and the POTW Worker, exposures can be decreased significantly through the use of
   readily available radon testing and mitigation technologies


ES.4  WHAT ARE THE RELEVANT REGULATORY AGENCIES?

The regulatory framework for radioactive materials in wastewater is complex.  There are many
levels of authority and types of requirements. Regulations are issued and enforced by various
agencies at different levels of government depending upon the type of radioactive material and
the agreements arranged.  Some information about the different regulatory agencies and their
activities that is germane to the types of materials that may enter wastewater and affect POTW
operations include the following.

The primary division of the regulatory framework is based on the origin of radioactive material.
In general, man-made radioactive materials are regulated differently than NORM and TENORM.
Radioactive materials consisting of source, byproduct, and special nuclear material are subject to
the provisions of the Atomic Energy Act (AEA). Radioactive materials used in the commercial
and private sector are subject to the rules of the NRC. When these types of radioactive materials
are used in the defense sector in weapons development operations, they are under the control of
the DOE.  However, DOE also regulates TENORM and accelerator produced radioactive
material under AEA authority at DOE facilities.

The AEA allows the NRC to  establish formal agreements with States, granting the States with
authority to develop and oversee the implementation of specific regulations regarding use and
possession of source, byproduct and special nuclear materials generated or used at these
facilities.  The 33 States with such an agreement (i.e., Agreement States) are required to maintain
a radiation protection program that is adequate to protect public health and safety and is
compatible with that of the NRC.

The lead Federal agency in the regulation of NORM and TENORM is EPA.  The DOE also
regulates TENORM at DOE facilities. In addition, some State and local authorities regulate


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various aspects of the NORM and TENORM materials discussed above. Other radioactive
materials are generally regulated by the States.

Under the Clean Water Act as amended, EPA establishes regulations addressing what industries
may discharge to POTWs, as well as regulations concerning the POTWs effluent and sewage
sludge. TENORM in wastewater effluents, sewage sludge and ash from a POTW could be
regulated by EPA. EPA currently regulates the use and disposal of sewage sludge produced by
POTWs under 40 CFR Parts 257 and 503, which at this time do not address radioactive material.
EPA also has  authorities under the Safe Drinking Water Act (SDWA) to set standards for
radionuclides in drinking water under the Clean Air Act (CAA) to limit radionuclide releases to
the air; under the Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA) to regulate the limits for both man-made radioactive materials and TENORM
releases from  contaminated facilities to a sanitary sewer; and under the Resource Conservation
and Recovery Act (RCRA) to regulate the non-AEA hazardous waste residuals.

Under the AEA and the Reorganization Plan 3 of 1970, EPA also has authority to establish
generally applicable environmental standards for the protection of the general environment from
radioactive materials. In addition, the AEA directs EPA to promulgate the Federal Guidance on
radiation exposure to workers and the public. Also, under the  Radon Gas and Indoor Air Quality
Research Act (1986) and Indoor Radon Abatement Act (1988), EPA  has authority to develop
national programs, technical policies, and guidance for controlling radon and indoor air pollution
exposure.

OSHA administers programs under the Occupational Safety and Health Act of 1970. Under this
law, OSHA has issued regulations for protecting workplace safety and health, including exposure
to hazardous or toxic materials, and radiation. Although these standards may not apply to  all
municipal wastewater treatment plant workers, these workers may be covered by their State
OSHA program.

State Agencies

In addition to the role of State agencies as NRC Agreement States, States have been active
regarding the  issue of potential radioactive contamination at POTWs. While many States (both
Agreement and non-Agreement States) regulate radioactive material, only some  have
promulgated regulations regarding TENORM, in a manner similar to the regulations regarding
man-made radioactive materials. For example, some States have established licensing and
inspection requirements for users of TENORM.  Other States require users of TENORM to
register with the State, rather than being issued a license.  To date,  13 States have approved
regulations for TENORM, and several States have either TENORM-related guidance or
regulations for TENORM generated in specific industries, this primarily includes the oil and gas
industries and the mining industry. Other States regulate TENORM to varying degrees through
their radiation control regulations without specific TENORM regulations (see Appendix E).

State radiation control programs are good sources of information about radiation protection
available to POTW operators.  State radiation control programs are composed of individuals who
have studied radiation and have experience with that particular State's radiation  problems. In
some instances, the State health agency or occupational safety office  may have developed  or

ISCORS Technical Report 2004-04                xxii                          Final, February 2005

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adopted specific radiation protection standards or guidance that could apply to municipal or other
wastewater treatment plants.

Local Authorities

The nature of the arrangement between a POTW and its customers will depend upon Federal,
State, and local law as well as any applicable requirements in implementing their EPA-approved
pretreatment program (40 CFR Part 403). In some cases, there are local permits issued to POTW
users that would govern the circumstances of discharges to the POTWs. In other cases, the
arrangements are purely contractual and the relationship between the POTW and its users
(including whether users  must notify the POTW before the discharging of radioactive material)
would be a contract condition.

POTWs may not have the same authority concerning radioactive material as they do for any
other material in plant influents. This is because the U.S. Supreme Court has held that for certain
activities covered by the AEA, Federal authority preempts other regulatory authorities whose
purpose is radiation protection. If the purpose is something other than protection of public health
against radiation safety hazards, State and local authorities might be able to impose additional
limits on radioactive effluent discharges.

Because preemption case law employs several subtly different tests that can be only
meaningfully applied to concrete facts, development of general guidance on the issue is difficult.
It is hard to predict whether unusual cost to the POTW caused by radioactive effluent discharges
would be a sufficient reason to impose more restrictive discharge limits than those permitted
under Federal law because there are no Federal cases in which (1) the specific facts corresponded
to the scenarios faced by  local POTW authorities and (2) the court decision addressed the
preemption issue.

ES.5 WHAT CAN A POTW DO TO DETERMINE IF THERE IS
       RADIOACTIVE CONTAMINATION? WHO  CAN  HELP?

The POTW operator should determine whether radioactive material is entering the sewage
treatment plant and is accumulating in the sewage sludge or ash, before conducting extensive
sampling or making major changes in sewage sludge or ash management practices.  There are a
number of steps that can be taken by the POTW operator to identify possible sources (man-made
and naturally-occurring) of radioactive material that may contribute certain radionuclides to the
system. For many POTWs, the levels of radioactive materials accumulating in the sewage
sludge or ash are inconsequential.  For some POTWs, the levels may be high enough that some
action to reduce potential exposures is prudent.

Information on possible sources of radioactive materials in the POTW service area should be
sought.  State and local agencies (e.g., regulatory agencies, geological surveys) should be
contacted for information on natural background levels of radionuclides in soils and ground
water. Either the NRC or State radiation control agency should be contacted for information
licensees who manage radioactive materials and who may be permitted to discharge wastewater
to the POTW. The State  or local drinking water regulatory agency can provide information on
drinking water systems that may be permitted to discharge residuals to the sewer system. These

ISCORS Technical Report 2004-04               xxiii                          Final, February 2005

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agencies also can assist in identifying specific types of radioactive materials that the POTW may
want to include in a sampling and analysis plan, if a sampling program is to be conducted.

The POTW operator is advised to review the recommended criteria, once information is obtained
on potential sources of radioactive material, to determine if further action is warranted.

1.  If the POTW is located in an area with elevated levels of uranium and radium in the soils and
   ground water, or if drinking water treatment plants cause elevated levels of radioactive
   materials to be discharged to the sanitary sewer system, it  is possible that radon gas may be
   elevated in certain poorly-ventilated indoor areas of the POTW where sewage sludge or ash
   is managed.  To determine whether there is any elevated exposure to workers in these areas,
   testing of the indoor air for radon may be appropriate.
2.  If there are industrial users  of TENORM that are permitted to discharge waste to the sanitary
   sewer system, it may be appropriate to monitor for radon in poorly-ventilated areas. It also
   may be appropriate to periodically analyze sewage sludge or ash samples for specific
   radionuclides associated with these particular industries.
3.  If there are many licensees  in the service area that manage other than sealed sources of
   radioactive material, or if the combined contribution to system-wide wastewater flow from
   licensed entities is greater than a small percent of the POTWs total flow, there may  be a need
   for a periodic sewage sludge or ash sampling program, which would include measurement of
   specific radionuclides associated with these licensees.  The POTW operator also may want to
   periodically review licensee discharge records, obtainable from the industrial sources  or from
   the Federal or State regulatory agency, for the type and quantity of radioactive materials that
   have been discharged to the sanitary sewer system.
4.  If there are elevated levels of NORM, or if there are drinking water treatment plants that
   discharge residuals to the sewer, or there are industries that manage TENORM that  discharge
   to the sewer, or if there are  many industries licensed to manage man-made radioactive
   materials that discharge more than a small percent of the POTWs total flow to their sanitary
   sewer system, it may be appropriate to routinely sample the sewage sludge or ash and to
   monitor indoor radon levels.

If, in the judgment of the POTW  operator, there are  sources present that could contribute
elevated levels of radioactive materials to the system, and an indoor air or sewage sludge or ash
sampling program is contemplated, the POTW should seek the assistance of a radiation
protection specialist, such as a certified health physicist, in developing a sampling and analysis
plan. A list of certified health physicists is  available by State  and city on the American Academy
of Health Physics (AAHP) Web site (http://www.hpsl.org/aahp/members/members.htm).
Consultants are marked with an asterisk.

Sampling of sewage sludge or ash, or monitoring for radon inside the POTW, should be
conducted to confirm the presence or absence of specific radionuclides, based upon the results of
investigations of possible sources. The sampling plan should  lay out a phased approach.
Initially, relatively inexpensive screening analyses should be performed to determine whether
further radionuclide-specific analyses are needed.  Gross alpha and gross beta activity analysis
and gamma spectrometry can provide an indication of whether specific radionuclides associated
with previously identified sources are present in the  sewage sludge or ash.  (See Chapter 5 for

ISCORS Technical Report 2004-04               xxiv                           Final, February 2005

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more detailed information on the analyses to perform.) The POTW operator can use this
information to determine whether any further sampling is needed or whether an unacceptable
exposure condition may exist that could be addressed by changes in management practices. Data
on specific radionuclide levels can be evaluated by using the screening tables provided in
Chapter 6 of this report. These screening tables allow a rough estimation of possible dose.
However, as previously stated, it is very important to contact a radiation protection specialist for
assistance in evaluating the results of preliminary sampling and analysis and the screening
calculations before conducting a more extensive sampling or monitoring program, or before
changing existing management practices.

ES.6  HOW CAN A POTW OPERATOR INTERPRET LEVELS OF
       RADIOACTIVITY DETECTED IN THE PLANT?

In general, there is no need for further action when estimated doses, using screening calculations,
are below the  ISCORS-recommended consultation level of 10 mrem/year. If doses are estimated
to be 10 mrem/year or greater, the POTW operator is advised to consult with its State regulatory
agency to determine if additional analyses should be conducted or if any response actions need to
be considered. The 10 mrem/year value should not be considered a radiation exposure limit.
The value also does not include  estimated or measured radon levels at the POTW. The POTW
can follow the phased approach  described below to assess the significance of levels of
radioactive materials detected in the sewage sludge or ash.

The interpretation of detected radioactivity levels in a POTWs sewage sludge or ash can be
conducted by  a series of steps based upon the use of tables generated from the ISCORS survey
results and dose modeling effort for various scenarios included in the full dose modeling report.
First, the POTW operator should compare the concentrations of radioactive material in the
sewage sludge or ash with the concentrations provided in the screening tables of Chapter 6.
These screening tables are based on an effective dose equivalent of 1 mrem per year, which is the
negligible individual dose determined by the National Council of Radiation Protection and
Measurements (NCRP 1993), and also is one-tenth of the ISCORS recommended consultation
level described above. As such, any measured concentrations of radioactive material that are less
than the respective values in the screening tables represent negligible potential exposures.
ISCORS recommends that no further action regarding radioactive materials in sewage sludge or
ash at a POTW is needed.

If any concentrations in the sewage sludge or ash exceed these values, then the estimated dose
can be calculated using the procedures provided in Chapter 6. The concentration of each
radionuclide that exceeds the screening concentration in the sewage sludge or ash sample is
multiplied by  the dose-to-source ratio for that radionuclide. Conservatism is built into these
values by the use of the 95th-percentile dose-to-source ratios.  The result (in mrem/year) for each
radionuclide is then summed to get an estimated total dose. When the calculated dose from all
radionuclides  exceeds 10 mrem/year, ISCORS recommends that POTW operators consult with
their State radiation protection regulatory agency.  This value is merely used as a guideline for
consultation.  It does not indicate a problem or suggest the need for any mitigation actions.

Calculations also are provided in Chapter 6 to estimate radon concentrations in indoor air based
on the Ra-226 and Th-228 concentrations in the sewage sludge or ash.  If these calculations

ISCORS Technical Report 2004-04                xxv                           Final, February 2005

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exceed the EPA recommended indoor radon action level of 4 pCi/L, then radon tests should be
performed.  If test results exceed 4 pCi/L, then action should be taken to mitigate.  These steps
are outlined in Figure ES. 1.
                      NO
              Potential sources entering
                POTW? (see criteria of
                      Section 5.2)
                                                 YES
                                                                 Evaluation of Radon (gray)


1


r
\
If NORM/'
sources,
testing fo
air. (Sec
                         Collect and analyze
                         sludge/ash samples.
                            (Section 5.3)
                 NO-
Are any analytical results
  of sludge/ash above
  Reference Values for
 Screening Calculations?
(Section 6.1.2 , Table 6.2
     or Table 6.5)
»	'    >
        YES
                         Determine total dose
                        by summing individual
                           nuclide doses.
                           (Section 6.1.3)
                 NO -
  Is total dose greater
   than Consultation
  Level of 10 mrem/y?
      (Chapter 6)
                               YES
    No further action is
   warranted regarding
  radioactive material in
      sludge or ash.
 • Consult with your
 State Radiation
 Control Program
 (Appendix E).
 • Consider site
 specific evaluations
 and refer to ISCORS
 recommendations.
 (Section 6.2 and
 Chapter?)
                       If NORM/
                      _TENORM
                       are
                       present
                                                               If radon
                                                               measurements
                                                               not available
                If radon
               "measurements"
                already
                available
                                                            Calculate indoor radon
                                                            concentration. (Section
                                                              6.1.2, Table 6.3)
                               NO
                                       Is calculated radon
                                       result greater than
                                     4.0 pCi/L or 0.02 WL?
                                              I
                                            YES
                                                             Test for radon in air.
                                                                (Section 5.3)
                                                                          NO —
                      Is measured radon
                      result greater than
                     4.0 pCi/L or 0.02 WL?
                                                                                           I
                                                                                         YES
 While radon levels
should be as low as
  practicable, no
  further action is
  recommended.
   Follow EPA
recommendations.
 (Section 6.1.4)
Figure ES.l   Flowchart for ISCORS Recommendations on Radioactive Materials in
                Sewage Sludge and Ash (See noted sections for details on recommendations.)
ISCORS Technical Report 2004-04
                          xxvi
                      Final, February 2005

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Depending on the results of the screening calculation and on current sewage sludge or ash
management practices, consultation with the State agency may result in (1) no further action is
needed; (2) additional measurements or analyses may be needed; (3) the appropriate State
regulatory agency provides direction on applicable State-level requirements; (4) a professional
radiation protection specialist or a health physicist is contacted for assistance in designing a
monitoring program or evaluating existing management practices; or (5) another agency should
be contacted for further guidance (EPA for NORM and TENORM sources and NRC for source,
special nuclear, and by-product material only).

When screening calculations suggest that potential  dose to workers or the public may be above
the acceptable radiation dose level agreed upon in consultation with the relevant State, the
POTW operator may want to conduct a more thorough evaluation of the levels detected in the
sludge, ash, or indoor air, based on site-specific conditions.  Such an evaluation may require
additional sampling or monitoring, use of site-specific parameters as input to the modeling
scenarios presented in the ISCORS Dose Modeling Report (ISCORS 2003b), creation of more
directly applicable modeling scenarios  than those used in the ISCORS Dose Modeling Report
(ISCORS 2003b), or actual physical surveys of potentially affected areas of the POTW or other
sludge management locations. The State radiation  control program should be apprised of the
results to determine appropriate standards for comparison.

Although the screening tables in Chapter 6 list 35 radionuclides, based on the ISCORS survey
results and the Dose Assessment Report's conservative scenarios, there were only
6 radionuclides of primary concern. The 6 radionuclides are Radium-226 and Radium-228,
which are NORM or TENORM; Thorium-228, Thorium-230, and Lead-210, which are either
NORM/TENORM or source material; and Iodine-131, which is byproduct material used in
medical applications.

The following factors may be important to consider when a POTW operator or contractor that
uses or disposes of sewage sludge or ash is deciding whether to perform measurements at the use
or disposal sites:

•  Indications that radioactive materials have been discharged to the sanitary sewer system and
   have entered the POTW,

•  Contract arrangements between the POTW and the dischargers,

•  Adequate and available records on  past sewage sludge or ash applications,

•  The frequency and amount of sewage sludge or ash applications to each site, and

•  Results of the screening calculations.

If results of the  screening calculations are above the State's acceptable radiation dose level, but
survey results are negative, the POTW  operator may consider taking soil samples at the land
application site  for analysis of radioactive materials, after consultation with appropriate Federal
or State authorities.
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ES.7  WHAT CAN  BE DONE TO REDUCE RADIATION DOSES AND
       RADON LEVELS?

If the results of the analysis of sewage sludge or ash samples or monitoring for indoor radon
indicate that some response by the POTW operator is needed, there are a number of actions
aimed at reducing radiation doses and radon levels that could be considered.  Consultation with
Federal or State radiation regulatory authorities and health specialists should be made prior to
taking actions to reduce exposures. They can assist the POTW operator in identifying possible
sources of the radionuclides, assist in establishing an appropriate course of action, and take
enforcement actions against dischargers if needed to correct the problem.  These regulatory
agencies may also assist the POTW operator in communicating with the public.

The regulatory agency may determine that the levels are not sufficiently elevated to cause
concern for worker or public health and safety. In that case, no additional action by the POTW
would be needed to protect workers.  However, the POTW operator should convey the
regulator* s findings to the POTW workers so that they know there is no cause for concern.  A
letter or other documentation from the regulator would be useful in communicating with workers
that the levels do not pose a concern.

POTWs, in consultation with the regulatory  agencies, should determine what can be done to
control sources of radionuclides entering the POTW. Each situation will be unique and the
appropriate actions will  vary from no additional action to regulatory enforcement.  The approach
taken will be affected by the answers to several questions that the POTW and the regulator may
explore.

1.  Where did the radionuclides come from?
2.  How did the radionuclides get to the POTW?
3.  How often are radionuclides expected to reach the POTW?
4.  Who is responsible for controlling the sources of the radionuclides?
5.  Are the appropriate controls in place to minimize releases of radionuclides to the POTW?

The POTW operator can work with the regulator to decide on appropriate actions to prevent
reoccurrences. Examples of these actions include the following:

•  Consult directly with likely industrial dischargers who may be routinely discharging
   radioactive material  to the sewer system, to explore the possibility of voluntary reductions in
   such discharges.

•  Encourage dischargers to use spill prevention measures to reduce the potential for accidental
   releases.

•  Impose appropriate additional local controls on the discharger, such as local discharge limits
   and regular reporting of discharges.

•  Require notification of planned or accidental discharges, or request notification from the
   source facility when future releases occur.  If the POTW lacks the authority to require
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   notification, consult with the Local Emergency Planning Committee (LEPC) and State
   Emergency Response Committee (SERC).

•  Request that regulators take enforcement action against dischargers who violate license
   conditions and contribute to the elevated levels.

•  Provide regulators with information on interferences in operating practices created by the
   dischargers.

•  Correct infiltration and inflow problems that transport naturally-occurring radionuclides to
   the POTWs sanitary sewer system.

If the release was a one-time accident and future releases are unlikely, action to prevent
reoccurrence may not be needed.

Where levels of radioactivity are elevated, the most important concern for the POTW operator
should be the protection of the workers and the public. If consultations with the regulatory
agency indicate that there may be a concern regarding exposure to the POTW workers, the
POTW operator may need to limit the amount of time workers spend near units with elevated
levels of radioactivity, increase the distance between workers and the radiation source(s),
increase the shielding between the source(s) and the workers, and increase ventilation rates in
areas where radium and radon are present.

Many of the measures that protect workers from radiation hazards are the same as those used at
POTWs to  protect against pathogens.  State health or occupational safety agencies, or OSHA
safety and health regulations and guidance for radiation exposures may be available or
applicable.  Personal hygiene practices such as washing hands before eating, drinking, or
smoking prevents ingestion of radionuclides as well as pathogens. Similarly, the use of personal
protection equipment (PPE—for the eyes, face, head, and extremities) such as protective
clothing, respiratory devices, and protective shields and barriers should be provided, if elevated
levels of radiation warrant, in dusty sewage sludge and ash handling areas to reduce the potential
for health risks from inhaling dust and any radionuclides associated with the dust, although such
measures would not protect against radon. Restrictions to limit personnel entry, or employee
time spent in areas with elevated radiation levels could also be recommended if the radiation
evaluations of the facility warrant.

Levels of radon gas in indoor air where average concentrations of Rn-222 exceed 4 pCi/liter, or
total radon  levels (Rn-220 and Rn-222 combined) exceed 0.02 Working Levels2 may indicate
that best management practices are warranted.

If elevated  levels of radioactivity have been identified, the POTW employees should be
informed.  The POTWs employees should also be provided with factual information on the risks
2  A measure of radon in air; 1 Working Level is equal to the total energy emitted by alpha particles from short
   lived radon decay products in equilibrium with radon gas in air at a concentration of 100 pCi/L
   (3.7kBqperm3).


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associated with the level of radiation exposure. Regulatory agencies or health physicists may
have literature available to assist in communicating with POTW personnel.

In evaluating levels of radioactive materials in sewage sludge or ash that is managed through any
type of land application process, it is possible that potential future sources of exposure may be
indicated through various dose-modeling scenarios. This situation may occur if the land
application site is eventually converted to another type of land use, particularly one with minimal
restrictions, such as residential development. Where such future exposures may be a concern,
the POTW operator may want to re-evaluate existing management practices to avoid creating an
unacceptable future exposure scenario, limit applications to reduce radionuclide buildup at the
site, or establish procedures whereby appropriate measures to control potential radon exposure,
such as standard practices for ventilating basements of buildings placed in these areas, are
utilized in such residential developments.  This may be a particular problem for monofills—land
fills with trenches that are used for disposal of sewage sludge and  ash only; while not evaluated
for radiation doses in the ISCORS dose assessment study,  such a site with elevated radiation
levels might require further land use restrictions.

In rare instances, sewage sludge and ash management may cause contamination of equipment at
the POTW or at disposal or land application sites.  If such situations occur, the POTW operator
may be responsible for removing the contamination.  Consultation with the regulatory agencies
should be pursued to determine any requirements that may apply.  Cleanup of contaminated sites
can be a costly endeavor for the POTW.  Depending upon the applicable Federal or State laws,
some dischargers may be liable for portions of the cleanup costs if their discharges caused the
contamination.  Legal counsel should be consulted as to whether any dischargers may be liable
for portions of the cost associated  with the  contamination of a particular site.
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1   INTRODUCTION

Authorities that operate Publicly Owned Treatment Works (POTWs) have many considerations
to address in the monitoring and daily operation of the treatment plants. One of these
considerations is the potential for radioactive materials to become concentrated in the treatment
plant. Radioactive materials are typically not a major concern at POTWs; however, they are a
component of the waste stream that is not well understood by POTW operators.

There are more than 16,000 POTWs in the United States. Along with nearly 35 billion gallons
per day of treated effluent, these POTWs generate approximately 7 million to 8 million metric
tons (dry weight) of sewage sludge every year.  The Nuclear Regulatory Commission (NRC)
estimates that of the more than 22,000 regulated users of Atomic Energy Act (AEA) radioactive
materials, about 9000 users have a potential to release radioactive materials to the sewer.
Naturally occurring radioactive materials may also enter the sewer systems.  (See Box 1.1.)  In
some situations, these radioactive materials may enter the wastewater treatment systems and
become concentrated in sewage sludge and ash. At the present time, there are no specific
Federal regulations that limit the levels of radioactive material in sewage sludge and ash.

In the United States, there have been no identified cases in which radioactive materials in sewage
systems have been a threat to the health and safely of POTW workers or the public. However,
there have been a small number of facilities where elevated levels of man-made radioactive
materials have been detected. (See Box  1.2 and Table 1.1.) Based upon this past experience,
there was a concern that radioactive material could concentrate in sewage sludge and ash and
could pose a threat to the health and safety of workers or the public.

The Sewage Sludge Subcommittee (Subcommittee) of the Interagency  Steering Committee on
Radiation Standards (ISCORS), comprised of representatives from several Federal agencies (see
Section 4.4 for more information about ISCORS), was created to assist NRC and the
U.S. Environmental Protection Agency (EPA) in  addressing this concern.  The Subcommittee
conducted a survey of radioactive material in sewage sludge and ash, performed dose modeling
of the survey results, and developed this report for POTW operators. (See
http://www.iscors.org/library.htm.)  The survey, which included samples from POTWs with the
greatest potential for elevated levels of radiation,  was undertaken by the Subcommittee to
provide an estimate of radioactive materials that may be found in municipal  sewage sludge and
ash. The survey results indicated that the majority of samples with elevated radioactivity were
attributable to naturally-occurring radioactive materials rather than man-made sources. The dose
modeling conducted by the Subcommittee suggests that the greatest potential for concern
involves potential exposures of certain POTW workers and occupants of buildings constructed
on long-term land application sites.

This report, based upon the information produced by the ISCORS survey and dose modeling
efforts, has three major purposes: (1) to alert POTW operators to the possibility of radioactive
materials concentrating in sewage sludge and incinerator ash; (2) to inform POTW operators
how to determine if, indeed, there are elevated levels of radioactivity in their sewage sludge and
ash; and (3) to assist POTW operators in deciding how to reduce potential radiation exposure
from sewage sludge and ash. A final draft of this report and the associated dose modeling report
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were published for public comment November 26, 2003 (68 FR 66503).  Changes have been
made to address comments received.
 Box 1.1       Recent Example of Radioactive Material Concentrating in Sewage Sludge
 There are certain geographical areas of the United States where relatively high radium
 concentrations occur in ground water.  Many public drinking water supplies depend upon
 ground water as their source of water, and some of these supplies have radium levels that
 exceed the drinking water standard for radioactive material. In treating these water supplies to
 remove the radium, a waste stream containing the removed radium may be created. If this
 waste stream is discharged to the sanitary sewer, the radium can be reconcentrated in the
 sewage sludge produced by the POTW. In some cases, farmers and the general public use
 treated sewage sludge with elevated levels of radium as an organic soil conditioner or
 fertilizer. Several States have been aware of such situations and are in the process of
 evaluating the radium levels in these materials.
 Box 1.2       Elevated Levels of Radioactive Material
 The term "elevated levels of radioactive material", as used throughout this report, refers to
 measured or detected levels of radioactive material that should, in the opinion of ISCORS,
 alert the POTW that some appropriate actions may be warranted.  The various appropriate
 actions, which are described in this report, are suggested as best or prudent management
 practices that could be taken to ensure that worker safety, public health and environmental
 protection have  not been compromised. The presence of such "elevated levels" in a particular
 sewage sludge or ash sample does not imply that a dangerous or hazardous condition exists,
 but rather that the POTW may want to consider taking some appropriate action.

 Since the "elevated levels" term has not been quantified, the use of this term does not imply
 some quantified incremental exceedance of an existing benchmark or standard.  Determining
 whether there is concern for worker safety or general public health at a measured level of
 radioactivity in a particular sludge sample is dependent on a number of factors, and should be
 considered on a case-by-case basis. Efforts by the ISCORS Sewage Sludge Subcommittee to
 conduct a survey and to perform dose modeling of radioactive material concentrations in
 various types of sewage sludge and ash products may provide perspective on the levels of
 radioactive materials that may be detected in sewage sludge or ash samples and on the
 appropriate level of concern for worker safety and general public health.
1.1    REPORTED INCIDENCES OF RADIOACTIVE CONTAMINATION

In its 1994 report, Nuclear Regulation: Action Needed to Control Radioactive Contamination at
Sewage Treatment Plants, the Government Accountability Office (GAO)3 described nine cases
3   In 2004, Congress changed the name of the US General Accounting Office to the US Government
   Accountability Office.


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where contamination was found in sewage sludge or ash or the wastewater collection system,
some of which have resulted in considerable cleanup expense to the POTW authority or specific
industrial dischargers of the wastewater (see Table 1.1).

 Table 1.1     Sewage Treatment Plants Where Elevated Levels of Radioactive
               Material Were Found
Location
Tonawanda, New
York
Grand Island, New
York
Oak Ridge,
Tennessee
Royersford,
Pennsylvania
Erwin, Tennessee
Washington, DC
Portland, Oregon
Ann Arbor,
Michigan
Cleveland, Ohio
Year
Found
1983
1984
1984
1985
1986
1986
1989
1991
1991
Radionuclides
Americium-241
Americium-241
Hydrogen-3
Polonium-210
Cobalt-60
Cesium- 134
Cesium- 137
Manganese-54
Manganese-54
Cobalt-58
Cobalt-60
Strontium-89
Zinc-65 & others
Americium-241
Plutonium-239
Thorium-232
Uranium
Carbon-14
Hydrogen-3
Phosphorous-3 2&3 3
Sodium-22
Sulfur-35 & others
Thorium-232
Cobalt-60
Manganese-54
Silver- 108m, 110m
Zinc-65
Cobalt-60
Actions Taken
State spent over $2 million cleaning
up treatment plant. No final
decision has been made regarding
radioactive material found in the
landfill.
No plant cleanup was warranted.
Soil around sewer line cleaned up,
and some special sludge disposal
occurred.
No plant cleanup was warranted.
Sludge digester cleaned up.
No plant cleanup was warranted.
Sewage lines cleaned up and
pretreatment system added.
No plant cleanup was warranted.
Treatment plant cleanup and related
activities have cost over $1 million.
Source: GAO, 1994
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There have also been a few additional cases identified that are still under evaluation. These
cases include Kiski Valley, Pennsylvania and Youngstown, Ohio.

The U.S. Nuclear Regulatory Commission (NRC) conducted a limited survey in the mid-1980s
to determine if radioactive material discharged to sewage systems was concentrated in sludge.
This took place at the facilities of 15 radioactive material users (licensees) and associated sewage
treatment plants. The sampling revealed no reconcentration problems (GAO 1994).

In 1986, the EPA published a literature review titled Radioactivity of Municipal Sludge
(EPA 1986). The literature search and follow-up telephone survey identified nine references
containing data on radioactivity concentrations in sewage sludges. These references included the
results of one-time surveys and ongoing monitoring programs by local authorities and State
agencies, results for individual facilities and facilities from as many as 10 cities, and reports of
incidents of sludge contamination reported by NRC.  The data obtained varied widely with
respect to the purpose of data collection, type of material sampled, number of samples, and
radionuclides analyzed. The available data identified four radionuclides as most frequently
reported: iodine-131, radium-226, americium-241, and cesium-137.

The NRC and EPA efforts to characterize radioactive materials in sewage sludge and ash in a
recent survey are discussed in Section 1.3 and Chapter 4.

1.2    SELECTED EXAMPLES OF  CONTAMINATION

Despite efforts to identify POTWs with radioactive contamination through surveys, most of the
cases involving elevated levels of radioactive materials at POTWs have been discovered through
measurements obtained for other purposes. As shown in Table 1.1,  at least five of these
instances warranted some mitigative action. Brief discussions of three of these cases illustrate
the need for the POTW authority to be aware of the possibilities of radioactive contamination
and the potential consequences.

Oak Ridge, Tennessee, Sanitary Sewage  Treatment Facility

In March of 1984, staff from the Oak Ridge weapons complex was performing a survey to
identify if any material contaminated with mercury or uranium from the complex had been used
as fill in the surrounding community. Elevated radiation readings were detected along Emory
Valley Road.  Soil samples revealed contamination from radioactive cesium-137 (Cs-137) and
cobalt-60 (Co-60). During this time, the Quadrex Corporation notified the Tennessee Division
of Radiological Health that contaminated sediment was detected in Quadrex's drain sump. The
Quadrex facility was involved in the decontamination of large pieces of radioactively
contaminated equipment, such as duct work and piping.  The process produced large volumes of
water with low levels of contamination. Subsequent examination of the sewage collection
system confirmed the soil and sediment contaminations were related and that the Quadrex plant
was probably responsible for the releases. Cracks in the  sewer line apparently resulted in the
radioactive material contaminating the soil.
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Further examination showed that contamination had also occurred at the Oak Ridge Waste
Treatment Plant (ORWTP).  Surveys at the ORWTP showed contamination of sewage sludge in
a digester storage tank, as well as sludge placed on drying beds in November 1983.

Quadrex agreed to assist in decontaminating the exposed contaminated sludge and to assist the
city in conducting measurements when portions of the old sewer line were to be excavated.  The
contaminated sludge was subsequently disposed in a sanitary landfill.

In the late 1980s, it was discovered that, in addition, routine, licensed discharges of several
different radionuclides (e.g., Co-60, Cs-137, and uranium) from multiple facilities resulted in
reconcentration of radioactive materials in sewage sludges.  This occurred even though the
discharge levels were reportedly only small fractions of regulatory limits.  (Since then, NRC's
regulatory discharge limits have been changed, which has reduced the concentrations of
radioactive materials in sewage sludge.) These routine discharges to the sewer led to the
expenditure of considerable resources over the past ten years.

The most significant concern related to radioactive material discharges faced by the Oak Ridge
POTW managers was the possibility that radionuclides, even at low levels, may have inhibited
their ability to continue land applying the sludge.  The practice of land application of the Oak
Ridge sludge was frequently called into question. In response, Oak Ridge developed a site-
specific, risk-based methodology for establishing radionuclide limits for its sewage sludge (see
Appendix F).

Portland,  Oregon, Contaminated Wastewater Collection Lines

Thorium-232 was detected in wastewater collection lines in Portland, Oregon, in 1989.  While
contamination did not reach the treatment facility, the collection lines were contaminated and
sewer workers took special precautions.  The generator of the wastewater containing the Th-232
was identified, remediated the contamination, and installed a pretreatment system to reduce
discharges.

The Cleveland, Ohio, Southerly Sewage Treatment Plant

The Northeast Ohio Regional Sewer District (NEORSD) operates the Southerly plant.  It is an
activated sludge facility that produced 103,000 wet tons of filter cake and incinerated 97,000
tons of the filter cake in 1992. During an aerial survey conducted in April 1991 of licensees in
the area, NRC inspectors noted elevated readings of radiation at the sewage treatment plant.
Subsequent ground level measurements indicated radioactive cobalt-60 was present, primarily in
areas where ash had accumulated in fill areas and storage lagoons.  Additional  surveys were
conducted in September 1991 and March 1992 to determine the  extent of the contamination.
These measurements of ash deposits indicated no new contamination had occurred since 1991.
The highest direct radiation readings were found when  a probe was lowered into animal burrows
made in the residue deposits.  This suggested that the concentration of material was higher below
the surface. From the records of the areas where the ash was placed, it appeared that the
contamination occurred in the late 1970s, and perhaps in the early 1980s.
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In 1992, NEORSD developed a remediation plan to remove ash from three storage lagoons that
were filled to near capacity. Remediation was completed in 1993, resulting in 174,000 cubic
yards of contaminated ash stabilized on site in two areas that are fenced (total of about 25 acres)
and capped with six inches of dirt.  Radiation measurement devices were placed at the periphery
of the area and seven monitoring wells were installed. Some contamination still exists in other
areas of the site and the NEORSD is currently working with the Ohio Department of Health to
assess its extent and degree. In 1994, NEORSD terminated sewer service to the wastewater
generator.

As of November 2002, the remediation costs incurred by NEORSD included about $1,800,000
for the onsite remediation and related activities and $120,000 to erect the fence around the fill
and holding pond areas. The NRC spent about $370,000 on radiation exposure assessment, soil
sampling and analyses, and other surveys.  The POTW authority engaged in a series of legal
actions to recover the costs from the waste generator; about $1,200,000 was recovered. To date,
the generator has failed to meet the NEORSD criteria for restoration of sewer service.

Livermore, California, Water Reclamation Plant

In the mid-1960s, small quantities of Pu-239/Am-241 were released to the Livermore, CA
municipal sewer system by the Lawrence Livermore National Laboratory (LLNL). These
releases, which did not exceed regulatory release limits in effect at that time, resulted in elevated
levels of alpha-emitting radionuclides in the sewage sludge. Dried sludge from the Livermore
Water Reclamation Plant (LWRP) was used for various purposes in the Livermore community,
particularly in the 1970s construction of a municipal park.  Additionally, dried sludge had been
released to various homeowners for residential gardening and horticulture.

Concerns over the potential health implications of Pu-239 contaminated sludge were raised in
1993 as a result of background soil samples collected in the municipal park by the
Environmental Protection Agency (EPA) that exceeded the expected background and  global
fallout levels for Pu-239/240. Numerous studies (see MacQueen et. al., 2002) conducted by
LLNL, EPA, and the Agency for Toxic Substances and Disease Registry (ATSDR) have
concluded that the elevated levels of Pu-239 in the municipal park were attributable to use of
LWRP sludges, but that potential doses to exposed individuals were well below any level of
concern.  ATSDR has recently performed additional dose modeling analyses based on data
collected at the time of the releases, and on more recent soil sampling, and has concluded that
"...the historic distribution of Pu-contaminated sludge is  determined to be no apparent public
health hazard.  ATSDR does not recommend any additional soil  sampling, since it considers that
available data,  while containing uncertainties ...provide an adequate basis for these public health
conclusions." (See the ATSDR website for information on the draft report released for public
comment "Plutonium 239 in Sewage Sludge Used as a Soil or a Soil Amendment in the
Livermore Community" — http://www.atsdr.cdc.gov.)
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Blue Plains, Washington, DC, Advanced Wastewater Treatment Facility

In April of 2000, contractors were excavating and demolishing abandoned ferric chloride and
ferrous chloride (pickle liquor) piping as part of a construction project at the Blue Plains facility.
The fiberglass reinforced pipe was placed in a dumpster and sent to a waste transfer station
where it was rejected due to above background levels of radiation detected by the scale house
radiation monitors at the facility.

A Certified Health Physicist (CHP) investigated the construction debris in the dumpster and
discovered that the inside surface of the pipe contained a thin layer of pipe scale that was
radioactive.  The scale was collected and sent to a laboratory for analysis.  The sample results
revealed that the scale contained several naturally occurring radionuclides with radium-226
being the most predominant.  The scale found in the pipe can be classified as a technologically
enhanced naturally occurring radioactive material (TENORM). Although the activity
concentrations and external radiation levels were relatively low the demolished piping could not
be disposed of as regular construction debris so it was properly packaged and shipped to a
radioactive disposal facility for processing and burial.

Following the discovery of the pipe scale, a controlled approach had to be taken to demolish and
dispose of the remaining ferric chloride and ferrous chloride pipes that were to be removed as
part of an upcoming chemical delivery system upgrade project. The contractor that removed the
piping developed and submitted a detailed plan describing the safety precautions and work
procedures to be used in the removal and disposal of the pipe.

The safety precautions and work procedures that were followed during this project were  similar
to the ones followed during an asbestos abatement project. Prior to disassembling the
contaminated piping it was drained, flushed, and pressure washed to remove the scale. The
workers that removed the piping received training with regards to the hazards of TENORM and
wore disposable protective clothing, respirators, gloves, and disposable boots while conducting
the work.  Ambient air monitoring was performed throughout the project with the purpose of
ensuring that the concentration of suspended radioactive particulates remained low.  In addition,
the workers wore personal  dosimeters to measure external radiation exposure over time.

All the contaminated piping,  identified as part of this project, was successfully removed in 2001
and 2002.
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1.3    CONGRESSIONAL INTEREST

A joint House and Senate hearing was held in June 19944 to officially release and address
questions raised in a GAO report, Actions Needed to Control Radioactive Contamination of
Sewage Treatment Plants (GAO 1994). The hearing and GAO report were stimulated by
concerns associated with the elevated levels of radioactive materials in sewage sludge incinerator
ash at the NEORSD's Southerly plant described in Section 1.2. Testimony presented by both
NRC and EPA during the hearing noted that there was no indication of a widespread problem in
this area and that the NEORSD incident appeared to be an isolated incident.  However, at the
hearing NRC and EPA committed to jointly develop guidance for POTWs and to collect more
data on the concentration of radioactive materials in samples of sewage sludge and ash from
POTWs across the country.

Since the hearing and GAO report, the NRC and EPA, with the assistance of other Federal
agencies participating on the ISCORS Subcommittee, have been addressing questions regarding
radioactive materials in sewage sludge and ash from POTWs.  The Subcommittee, formed by
ISCORS in 1996, developed an initial draft of this ISCORS report for POTWs, which was issued
in May 1997 for public comment. A revised draft of this guidance was issued for comment in
June 2000. The Subcommittee has also conducted a comprehensive survey of radioactive
materials in sewage sludge and ash from 313 POTWs nationwide.  The survey  focused on
POTWs in regions where the potential for elevated levels of radioactive materials in wastewaters
may exist. The results of this survey are available in a survey report (ISCORS 2003) and are
summarized in Chapter 3 of this report.
4  Radioactive Contamination at Sewage Treatment Plants, Joint Hearing before the Committee on Governmental
   Affairs, U.S. Senate and the Subcommittee on Environment, Energy, and Natural Resources of the Committee
   on Government Operations, House of Representatives, One Hundred Third Congress, Second Session,
   June 21, 1994. S. Hrg. 103-1034.


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2  PURPOSE

One purpose of this report is to inform POTW operators of the possibility for radioactive
materials to concentrate in sewage sludge and incinerator ash. A second purpose is to help
POTW operators determine what to do about the radioactive materials present in their sewage
sludge or ash. This guidance is not intended to serve as a comprehensive reference regarding
radioactivity.  However, it provides information on important issues related to the control of
radioactive materials that may enter POTWs.

This report poses the following questions; answers to these questions are found in various
sections of this report, as cited below:

Is  There Radioactive Material in My Treatment Plant?

One of the first things a POTW operator needs to realize is that there is radioactive material in
the soil that the building foundation rests on, in the indoor air of the facility, and in the
wastewater that the system treats.  Chapter 3 discusses why there is radioactive material in
sewage sludge and when the presence of these materials may be of concern. Chapter 5 discusses
how to determine if there are elevated levels of radioactivity and who can help if there are
elevated levels.

Who  Are the Other Players in My Specific  Case?

The Federal and State regulatory authority over radioactive materials, sewage sludge,  and
industries that may discharge into sewage systems is complex.  Further information on regulatory
authorities is available in Chapter 4.

What Should the POTW Authority Consider Doing to Determine if There Is  a
          Problem With Elevated Levels  of Radioactive Materials?

There are several steps to consider in evaluating whether a POTW may have a problem regarding
radioactivity.  Chapter 5 describes what a POTW can do to determine if there are elevated levels
of radioactive materials at their facility, and who can help. Appendix A is a primer on
radioactivity and radioactive materials. The information provided in Appendix A should be
helpful in understanding the nomenclature and some of the basics about the health risks  of
radioactivity.

What Can the POTW Authority  Do  if Elevated Levels Are Found?

There are a number of options that a POTW operator may want to  consider if elevated levels of
radioactive materials are found.  Chapter 7 presents the options, as well as their legal and
technical aspects.
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3 WHY IS THERE RADIOACTIVE MATERIAL IN SEWAGE
   SLUDGE AND ASH? WHAT IS THE CONCERN?

Radioactive materials are an ever-present component of the natural environment and are also
concentrated or produced through some human activities.  Generally, the presence of radioactive
materials is a concern only when concentrations become sufficiently elevated above background
levels to potentially pose a health risk or in cases where the ability of a POTW to use or dispose
of the sewage sludge or ash is inhibited.  There have not been many known occurrences of such
elevated concentrations since the 1980s.  There have been no identified cases in which
radioactive materials in sewage systems have been a threat to the health  and safety of POTW
workers or the public. This section explores sources of radioactive materials that may reach a
POTW and why they may become a concern to POTW personnel and the public.

3.1    TYPES OF SOURCES

There are three general sources of radionuclides in the environment:  natural sources, natural
sources concentrated or enhanced by human activity, and man-made sources. Radioactive
material from all of these types of sources has the potential to enter sewage systems.
 Box 3.1       Sources of Radioactivity
 Natural Sources:  Geologic formations, water, and soils that contain small amounts of
 radioactive elements, typically known as naturally-occurring radioactive materials (NORM).

 Technologically Enhanced Naturally-Occurring Radioactive Materials (TENORM):
 Naturally-occurring radioactive material whose radionuclide concentrations or potential for
 human exposure have been increased by any human activities.

 Man-made Sources: Radioactive materials generated by human activities such as accelerator
 material; nuclear byproduct material, source material, or special nuclear material; and fallout
 from nuclear weapons testing.
3.1.1     Natural Sources

Natural sources of radiation include geologic formations and soils that contain uranium, radium,
radon, and other nuclides that are radioactive.  Water originating in or moving through the
formations and soil may transport the radioactive materials either dissolved in the water itself or
attached to dissolved and suspended solids in the water. Radon is also released to the
atmosphere from soil and water. Radon can enter any building through ground contact openings
in a concrete slab or foundation wall. Underground connections to manholes, piping conduits,
and utility tunnels usually provide additional pathways for radon entry in industrial facilities
similar to POTWs.

The amount of naturally-occurring radioactive materials in the ground varies widely.  Some areas
with elevated levels of naturally-occurring radioactive materials include locations such as those


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underlain by phosphate ore and uranium ore deposits.  The lowest levels are generally found in
sandy soils of the Atlantic and Gulf Coasts.  Figure 3.1 shows average indoor screening-level
radon concentrations by county in the United States. These average concentrations may roughly
correspond to the general levels of uranium and radium in soils in the area.  The map in
Figure 3.1 provides general indication of the distribution of radon in homes across the United
States, but it is not, however, a valid tool for predicting the radon concentration in any particular
building. The general advice from EPA since 1989 has been that all homes, schools, and Federal
workplaces be tested for radon (EPA 1994, EPA 2002, EPA 2004, and Fisher 2003).  EPA
recommends by this publication that testing should be  considered in certain cases by POTWs as
well.
 Sucrn
                                                   «*i» ctasfcratar fcrPuarto *c= is uictei ae.eloo-riert
Figure 3.1    Average Indoor-Air, Screening-Level Concentrations of Radon in the
              United States (from EPA 1993a). Zone 1 counties have a predicted average
              indoor screening level greater than 4 pCi/L. Zone 2 counties have a predicted
              average between 2 pCi/L and 4 pCi/L. Zone 3 counties have a predicted average
              less than 2 pCi/L.

Although Figure 3.1 and Figures 3.3 and 3.4 in Section 3.3.3 may be generally useful for
determining if a POTW is in a high NORM area, elevated NORM  may be present in the ground
water as a result of other factors related to local geologic and land  use conditions.  For example,
southern New Jersey has elevated radium in ground water, even though the information
contained  in Figures 3.1, 3.3, and 3.4 indicate otherwise. In 1983-89, the U.S. Geological
Survey (Kozinski 1995) conducted a study of the effects of geology,  geochemistry, and land use
on the distribution of naturally occurring radionuclides in ground water in the aquifer system in
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the Coastal Plain of New Jersey. They concluded that concentrations of radium-226 and radium-
228 tended to be higher in water samples from wells in areas where the Bridgeton Formation
(predominantly gravel) and agricultural land use are present within a 500 meter radius of the well
head. Irrigation of agricultural land commonly is necessary because of the low moisture capacity
of the well-drained soils developed on the Bridgeton Formation.  Irrigation tends to increase the
leaching of nutrients (such as calcium, magnesium, and nitrate) from the soil. Because soils
developed on the Bridgeton Formation are well-drained and naturally low in nutrients, these soils
require the application of large amounts  of fertilizer and lime for optimal crop production.

Leaching of uranium and radium from the minerals of the Bridgeton Formation is suspected to
be a  source of the radium in the ground water. The correlation of radium concentration with the
concentrations of chemical constituents added to soil in agricultural areas indicates that leaching
of radium may be enhanced by the chemical processes in ground water that are associated with
the addition of agricultural chemicals to  the geochemical system. These effects are especially
severe when combined with the naturally acidic ground water chemistry of southern New Jersey
because acidic water tends to dissolve radium more easily in the first place (Szabo 1998).

While national maps of soil uranium and radon show the areas with the most radioactive
elements  present, they do not necessarily show where some radionuclides can be most readily
dissolved. Radium especially is more soluble in naturally acidic areas such as southern New
Jersey even though the amounts  of radioactive elements in soil may not be as high as  in some
other parts of the State. To determine whether there is any indication of naturally-occurring
radioactive material that may enter the wastewater system, the POTW operator should contact
the State Radiation Control Program (see Appendix E)  or the State Drinking Water Program for
information specific to the area served by the POTW.

3.1.2    Technologically Enhanced Naturally-Occurring Radioactive
          Materials

Levels of naturally-occurring radioactive materials can be enhanced by human activity and by
technologies associated with extraction processes.  These materials, when enhanced by human
activity, are known as  Technologically-Enhanced Naturally Occurring Radioactive Materials
(TENORM).  Examples of TENORM include articles made from or coated with naturally-
occurring radioactive materials and wastes from mineral and petroleum production, burning coal,
geothermal energy production, quarry operations, and the processing of large volumes of water
containing dissolved radon gas.

TENORM may be introduced to the sewage system from ground and surface water, plants and
food, as well as from potential discharges from industries (e.g., water treatment plants, mining
and petroleum industries, fertilizers, electronics, ceramics, foundries and paper/pulp mills).  EPA
is in  the process of studying this potential radiation hazard.  Additional information on
TENORM may be found in NAS (1999), Eisenbud and Gesell (1997), and at
http://www.epa.gov/radiation/tenorm.
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3.1.3    Man-Made Sources

Radioactive materials are also generated by human activities.  Man-made sources include
radioactive material produced for and as a result of the operation of nuclear reactors (i.e., source
material, special nuclear material, and byproduct material) and from nuclear accidents (e.g., the
Chernobyl incident).  Other man-made sources are produced from the operation of accelerators
and from global fallout from testing of nuclear weapons.

NRC and Agreement States have licensed about 22,000 facilities to use radioactive materials and
about 9000 of these have the potential to release radioactivity  to sewers. Licensees include
utilities, nuclear fuel fabricators, universities, medical institutions, radioactive source
manufacturers, and industrial users of radioactive materials. Laboratories and universities use
man-made radioactive materials (e.g., carbon-14) in research,  including in genetic research, the
study of human and animal organ systems, and in the development of new drugs. Radioactive
materials are also found in consumer products such as smoke  detectors, luminous watches, and
tobacco products (NCRP, 1987b). Radioactive materials are prescribed to medical patients for
the diagnosis  and treatment of illnesses (Murray and Ell, 1998 and the website of the Society of
Nuclear Medicine at http://www.snm.org).

Nuclear power plants and nuclear fuel cycle facilities are not considered significant sources of
radioactive materials in POTWs because almost all of these facilities maintain their own sewage
treatment systems that are not directly connected to the POTWs.  Some fuel cycle facilities treat
their wastewater onsite then discharge the treated effluent to the municipal sewer system
according to a permit issued by the local POTW. In these cases, they may also have
commitments in their licenses to sample the POTW sewage sludge for radionuclides.  Any
sewage sludge shipped offsite is monitored to ensure that only low levels of radioactive material
are present. (See NRC Information Notice 88-22 - "Disposal  of Sludge from Onsite Sewage
Treatment Facilities of Nuclear Power Plants.")  Thus, potential quantities of radioactive
materials released by nuclear power plants and fuel cycle facilities into sewage treatment
systems are generally quite small compared to some other types of licensees. Contaminated
clothing from these facilities is  sometimes sent to a licensed nuclear laundry offsite that may
discharge wastewater to a POTW.  Other waste from the facilities containing radioactive
materials is collected, treated, and packaged for disposal in licensed low-level radioactive waste
disposal facilities.

3.2    HOW RADIOACTIVE MATERIALS  REACH POTWS

Radioactive materials reach POTWs primarily via wastewater discharges.  Chemicals and other
materials (e.g., lime, fly ash, waste pickle liquor, or wood ash) used by the POTWs may also
contain radioactive materials. In addition, infiltration  and inflow into sanitary sewers may
contain radioactive materials. Table 3.1 summarizes the sources and pathways by which
radioactive materials may reach POTWs.
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 Table 3.1    Sources and Potential Pathways for Radioactive Materials to
               Reach POTWs
 Discharges to POTWs
Treatment Process
Infiltration and Inflow
 •   Drinking water and
     drinking water residuals
     that contain NORM

 •   Sewage with radioactive
     materials from food and
     from medical procedures
 •   Wastewater from NRC or
     Agreement State
     licensees handling
     radioactive materials in
     unsealed form
 •   Wastewater from
     industries handling or
     processing materials
     containing NORM

 •   Exempt or unlicensed
     radioactive materials
   Process chemicals with
   radioactive materials
   (e.g., lime, fly ash, waste
   pickle liquor, or wood
   ash)

   Wood chips, sawdust, or
   other bulking agents used
   in composting sewage
   sludge

   Any process that agitates
   or aerates water liberates
   radon gas.
•  Infiltrating ground water
   containing NORM,
   including radon gas.

•  Surface waters runoff
   containing NORM or
   fallout, via combined
   sewers
The local drinking water supply may contain NORM found in the soil or geologic media from
which the water is removed.  The local drinking water treatment facility may remove some of the
radioactive materials from the raw water by aeration, ion exchange, precipitation, coagulation, or
filtering of dissolved or suspended solids.  The resulting residuals are sometimes disposed of by
discharge to the wastewater collection system. Any radioactive materials remaining in the
finished water supply (i.e., radon) would eventually be transported to the POTW along with
wastewater. Even if the water is not treated, the NORM in the raw water is transported to the
POTW either directly through sewage lines or by the collection of septage from individual septic
tanks.

As discussed previously in Section 3.1.2, a large number of industries utilize mineral ores and
materials that may contain naturally occurring radionuclides.  These materials may be present in
the mineral molecular structure, as a contaminant coating mineral grains, or as radioactive
minerals included in the raw material for an industrial practice. These radionuclides become
concentrated in solid or liquid form.  In some instances, industries that use large amounts of
water for manufacturing processes can accumulate naturally occurring radionuclides in their
liquid wastes or sludges. Not all industrial facilities have pre-treatment prior to discharging to
the sanitary sewer system, so it is possible that solid particulate matter or liquid wastes
containing TENORM may enter the POTW facilities.  It is also possible that local sources of
ground or surface water in the service area may contribute to higher levels of NORM in the
facility; this may be especially true if local water treatment plants discharge their residuals to the
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sewer. The POTW operator should use their list of industrial dischargers to the system, noting
the type of products that are manufactured, and compare that list with the types of industries
known or suspected to utilize or generate NORM and TENORM wastes in Section 3.1.2. This
can then be used, along with guidance from State and EPA radiation program officials, to
evaluate the potential sources of contamination entering the system.

In many cases, naturally occurring radioactive elements may be mobilized, or leached, from
mineral waste or ore used in industrial processes to form TENORM. Uranium is particularly
soluble in acidic waters, but it can also be mobilized in basic solutions.  While radium is
generally not soluble except in the presence of certain ionic solutions (e.g., barium), it can be
suspended in water. Process operations first leach  and then concentrate the radioactive materials
in the product and waste streams. Industrial facilities that utilize large quantities of water may
also inadvertently concentrate the naturally occurring radionuclides present in all water sources.
Radioactive mineral scales may accumulate in piping or filters at processing and manufacturing
plants, or radionuclides may accumulate in process wastewater, sewage sludge or ash.
Manufacturing facilities that utilize certain minerals to make finished products may accumulate
radioactive wastes in liquid or solid forms. Knowledge about radionuclides associated with
certain minerals and metals used in a variety of industries and small businesses is limited in those
industries.  It is possible that companies without pre-treatment facilities may inadvertently
discharge these radionuclides to the sewer system.  Regulation of industries or companies that
create or utilize NORM or TENORM will vary by  State.

As a hypothetical example, a small business making ceramic products uses ground zircon flour
to make the glaze for its finished product. Excess flour, containing uranium and radium as a
decay product, accumulates as a dust in a  finishing room of the company, the company washes
its fired ceramics before packing them for shipment, the wastewater and dusts are discharged to
the sewer without any pre-treatment.  Knowledge about radionuclides associated with certain
minerals and metals used in a variety of industries  and small businesses is limited.

The following are known to have TENORM contamination potential:

•  Water treatment facilities (radium scale and sludge contamination in wastes and filters)

•  Paper and pulp facilities (radium scale and sludge contamination)
•  Ceramics manufacturing (zircon, uranium in wastes and molds)

•  Paint and pigment manufacturing (thorium, uranium, radium in wastes from titanium ores)

•  Metal foundry facilities (zircon contamination in molds for metal parts/machinery, thorium in
   welding rods)

•  Optical glass (thorium incorporated in glass)
•  Fertilizer plants (uranium, thorium, radium, radioactive potassium associated with fertilizer
   production, concentrations in wastes, filters, products, metal piping scales)

•  Aircraft manufacture (depleted uranium counterweights; in older facilities, radium dials,
   nickel-thorium alloys used in engine manufacture)

•  Munitions and armament manufacture (depleted uranium in ammunition and armor)

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•   Scrap metal recycling (TENORM-contaminated piping and metal)
•   Zirconium manufacturing

•   Oil and gas production, refining and storage (TENORM (radium)-contaminated scale or
    sludge in piping, tanks, separators)

•   Electricity generation,  cement and concrete product manufacture (coal ash containing
    uranium, thorium and radium particularly in fly ash component)

•   Geothermal energy production (TENORM (radium)-contaminated scale or sludge in piping,
    tanks, separators)

The following list of minerals are  known to either be radioactive, or are known to have the
potential for radioactive contamination by inclusion of radionuclides in their molecular structure,
or association with other radioactive minerals in their original ore body.  A list of industries that
use these minerals is included for information purposes (USGS 1973). The inclusion of an
industry in this listing does not necessarily mean that radioactivity may be present at any or all
such sites.
 Copper



 Fluorospar (Fluorite)



 Gypsum



 Molybdenum

 Niobium
 Phosphate
 (Phosphorous)
 Potassium
 (Phosphorous)


 Precious Metals
 (gold, silver)
Used in manufacturing copper wire, nails, and copper sheeting, brass,
bronze, electrical and electronic equipment, war munitions, and
chemical reagents.

Used as a flux in manufacturing steel, enamelware, opalescent glass,
hydrofluoric acid; refining of antimony and lead; and manufacturing
vases, paper weights, and dishes.

Used as a flux in glass and porcelain manufacturing, retarder in cement,
filler in fertilizers.  Alabaster is used for statues, vases, lamps,  and
pedestals.

Used in manufacturing steel and iron castings and high speed tools.

Used in manufacturing stainless steel, high temperature alloys, jet
engines, and gas turbines.

Used in fertilizer manufacturing, as phosphoric acid for industrial and
food manufacturing uses, water softeners, and in manufacturing glass
and ceramics.

Used in manufacturing glass, optical glass, incandescent light bulbs,
black and gun powders, dyeing and tanning, and as (cyanide) solvent in
gold extraction and photography.

Used for coinage and jewelry, in manufacturing scientific and electronic
instruments, photography, gold plating, lettering, and dentistry.
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 Rare Earths
 (yttrium, lanthanum,
 monazite, bastanite)

 Tin
 Titanium
 (Leucoxene, ilmenite,
 rutile)
 Tungsten


 Vanadium


 Zircon
Used as thorium in manufacturing electrodes, optical glass, refractory
manufacture, and in the textile industry.
Used in manufacturing tin plate or sheet tin, as solder, bronze, tin
amalgam, gun metal, type metal, speculum metal, pewter, and a
polishing powder.

Used as a steel additive; for metal for airplanes and ships, welding rod
coatings; in carbide cutting tools, white pigment for paint manufacture,
lacquer enamels and rayon, glass, and highly opaque, light weight
paper.

Used in manufacturing X-ray tubes, filaments in incandescent lights,
and automobile engines.

Used in manufacturing special steels and bronzes, high speed tools,
ceramics, inks, and for silk dyeing.

Used in strengthening steel, brass, and copper; widely used in ceramics
as a glaze, as coating for ceramic and metal molds, refractory bricks,
polishing powder, pyrotechnics, and sandblasting powder. Used in
manufacturing aircraft engines and parts, cutting tools, nuclear reactors,
surgical tools, electric arc lamps, and in the tanning and manufacturing
of textiles.
Other potential sources of radioactive materials include facilities with NRC and Agreement State
licenses. All licensees are authorized by the regulations (see Section 4.1 for details about the
regulations) to discharge radioactive materials to the sewers, but are not required to report such
discharges.  Although NRC licensees are not required to report such discharges, they are required
to keep records that are subject to inspection. However, it is estimated that only 20% of NRC
and Agreement State licensees actually discharge to the sewer system.  The main reason most
licensees do not discharge radioactive material to the sewers is that they possess only sealed
sources, which are extremely unlikely to be released into sewers.  Other licensees may have
unsealed sources, but not in liquid form, and hence there is no radioactivity released to
wastewater.

Many licensees which use radioactive materials in liquid form do not need to discharge to the
sewers because (1) the materials used are very short-lived and can decay in short-term storage
and then be discharged as non-radioactive, or (2) the material may contain wastes that cannot be
disposed of into sanitary sewers, if the material is non-dispersible or due to the presence of other
non-radioactive pollutants.  These pollutants may be prohibited from discharge into sewers by
regulations issued under the Clean Water Act or the Resource  Conservation and Recovery Act,
rather than by NRC's regulations.

Radioactive material is handled in "unsealed" forms in the nuclear fuel  fabrication industry, in
the production of radiopharmaceutical medicines, and in research. Limits in quantities and
concentrations that the NRC and Agreement States allow to be discharged to the sanitary sewer
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are based on a fraction of the dose limit that can be received by an individual member of the
public (see Section 4.1 for the dose limits).

Table 3.2 lists types of NRC licensees that could dispose radioactive materials into the sewer
system and radionuclides previously found in POTW sewage or those that could be present.  It
should be noted that a broad scope licensee is usually authorized to possess and use any
radionuclide with an atomic number from 1 to 83. This means that many more radionuclides
than those listed in Table 3.2 could be disposed into the sanitary sewer. The half lives and types
of radiation emitted by these radionuclides are listed in Appendix A, Table A.I.

Licenses may be issued for specific applications, such as for industrial radiography, irradiators,
well logging or specific medical uses. In such cases, the application, the physical and chemical
states and the radioactivity of the materials are well  defined. In other cases, the application is not
as well defined, such as medicine and research. The physical and chemical form and activity
will depend on the nature of the medical treatment, diagnosis or research being conducted.  To
accommodate undefined or changing applications, broad scope licenses are issued (e.g.,  to large
medical institutions, universities, and research facilities).

Two other domestic sources of radioactive materials in sewage are medical procedures and food.
Radioactive materials (e.g., iodine-131, technetium-99m, strontium-89, and thallium-201) used
in the diagnosis and treatment of medical conditions are also discharged to the POTW when
excreted. For POTWs that serve large medical institutions, a major portion of the radioactive
discharges to the sewer comes from patients. POTWs serving large medical centers and
universities in which extensive research is conducted may receive discharges from both  the
research activities and from patients.  A complicating factor is that some patients reside  far away
from the medical centers. Wastes from these patients will probably be discharged to the POTW
serving the patients' residences. Refer to Table 3.2 for radionuclides commonly used in the
medical facilities.

Radioactive material can also enter a POTW in chemicals and other materials used in wastewater
treatment and sludge processing. In addition, infiltrating ground water may contain radioactive
materials from natural sources that were either dissolved or attached to suspended solids as the
water flows through soils and geologic formations.  Similarly, surface water and sediment in
runoff containing NORM or fallout may enter the POTW via combined sewers.  The amount of
radioactive materials entering POTWs by infiltration and inflow will vary depending upon the
degree of infiltration and inflow, and the amount of natural  sources and fallout in the service
area.
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 Table 3.2     Types of NRC and Agreement State Licensees and Typical
               Radionuclides
         Academic
       (broad scope)
         Medical
   (broad scope, nuclear
       pharmacies)
  Manufacturing and Distribution
  (broad scope, nuclear laundries,
    decontamination services)
 Carbon-14
 Cobalt-60
 Cesium-137
 Hydrogen-3
 Iodine-125/131
 Iron-59
 Manganese-54
 Phosphorus-32
 Phosphorus-33
 Sulphur-35
Carbon-14
Chromium-51
Cobalt-57
Gallium-67
Indium- 111
Iodine-125/131
Iron-59
Phosphorus-32/33
Strontium-89/90
Sulphur-35
Technetium-99m
Thallium-201
 Research and Development
       (broad scope)
         Others
 (e.g., ore processing mills,
   uranium enrichment
         plants)
Americium-241
Antimony-125
Cobalt-60
Cesium-134/137
Hydrogen-3
Iodine-125/131
Manganese-54
Niobium-95
Phosphorus-32
Plutonium-23 8/23 9/240
Polonium-210
Strontium-89/90
Sulphur-35
Uranium-233/234/235/238
Zirconium-95
 Carbon-14
 Cesium-134
 Hydrogen-3
 Iodine-125/131
 Phosphorus-32
 Sulphur-35
Plutonium-23 8/23 9/240
Radium-226
Thorium-228/232
Uranium-233/234/235/238
3.3    WHY RADIOACTIVE MATERIALS MAY BE OF CONCERN AT
       APOTW

As with any other building, POTWs may have elevated levels of radon gas in the indoor air, due
to pressure driven infiltration of soil gas. Commercial facilities that operate HVAC equipment
or process air flows that depressurize the indoors relative to the ground (or outdoors) will
increase this type of infiltration. Additionally, POTWs may have pipe tunnels and conduits that
usually provide opportunities for easy radon transport into the facility. Finally, any process that
agitates or aerates large quantities of water containing even small concentrations of radon may
result in large indoor air concentrations.

Although it is unlikely that radionuclide levels in sewage sludge and ash at most POTWs across
the country pose a concern for treatment plant workers or the general public, it is possible that
radioactive material from natural and man-made sources could become concentrated in sewage
sludge and ash at some POTWs. This could cause interferences with POTW operations,
including cost effective use or disposal of sewage sludge and ash. However, there are low
amounts of radioactive materials that are legally authorized, under Federal and State laws and
regulations, to be disposed into the sanitary sewer system. This  section addresses POTW
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operations that have potential to cause concerns due to exposure to radiation. (For more
information regarding radioactivity, see Appendix A.)

3.3.1      Reconcentration of Radioactive Materials at POTWs

The purpose of wastewater treatment facilities is to reduce or remove pollutants from wastewater
in order to ensure adequate water quality before the treated effluent is reused or discharged to
surface waters.  The removal of radionuclide contaminants by various wastewater treatment
processes and the usual association of these contaminants with solids can cause the concentration
of the contaminants to increase, or reconcentrate, in sewage sludge and ash. Radioactive
materials disposed of into the sanitary sewer in dilute form may become reconcentrated in the
sludge solids during different stages of wastewater treatment and sludge processing, in a manner
similar to some heavy metals.

Reconcentration may occur during physical, biological, or chemical processes.  Sludge treatment
and processing may result in increasing the concentration of the radioactive contaminant by
decreasing the concentration of other components. Final concentration will depend on the
characteristics of the processes used at the treatment facility, the efficiencies of those processes,
as well as the chemical  form of the radionuclides and their half-lives.

Radioactive materials found in sewage are partitioned between the liquid and solid phases of the
influent. During treatment, the concentrations of radionuclides change as the solids are removed
and the treatment processes remove radionuclides from the wastewater.  Because radionuclide
concentrations in wastewater influents are very dilute, there is generally no concern unless the
radionuclide concentrations are increased, or reconcentrated, during the treatment process.

A study performed for NRC (Ainsworth et. al., 1994) reported that reconcentration of suspended
radionuclides is very possible in primary treatment. NRC methods of determining solubility
(NRC Information Notice 94-07 "Solubility Criteria for Liquid Effluent Releases to Sanitary
Sewage under the Revised 10 CFR Part 20") allow some suspended material to be discharged to
the sewer system and, therefore, do not guarantee that reconcentration will not  occur. This study
also indicated that dissolved radionuclides (those not associated with the suspended solids) are
unlikely to  be reconcentrated during primary treatment. Reconcentration is possible  during
secondary treatment, but neither the mechanism(s) or unit process(es) involved is (are)
understood in a quantitative manner.

Reconcentration can also occur during sludge treatment (Ainsworth et al., 1994).  It can
potentially  result from the physical, chemical, and biological removal of radionuclides from the
sewage  and sewage sludge produced during wastewater treatment. Physical processes that
increase the solids content of the sludge without loss of radioactive materials may lead to
reconcentration. Sludge handling techniques that may contribute to reconcentration include
digestion, dewatering, and incineration.  Incineration may be the most significant process,
because the total mass of the sludge is greatly reduced by water removal and combustion of
organic material.

Although there is a potential for a reconcentration of radioactive materials in the sewage sludge
or ash at POTWs, there have only been limited surveys of radionuclide levels in sewage sludge

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or sludge products. A recent study by the Association of Metropolitan Sewerage Agencies
(AMSA) revealed the presence of both man-made radioactive material and NORM at low levels
in sewage sludges and sludge products (NBP 1999). AMSA coordinated an extensive sampling
effort as part of their national survey conducted in 1995. While this was a voluntary survey and
was not structured to ensure a statistically representative result, samples from 55 POTWs in 17
States do provide a significant database.  The ISCORS survey (ISCORS  2003) estimated
potential doses from seven typical sludge management scenarios, based on the results of analyses
of sewage sludge and ash products from 313 POTWs.  The results of both surveys are generally
consistent.  Table 3.3 summarizes results from the AMSA study and the ISCORS survey.
Table 3.4 provides typical ranges of radioactive material concentrations found in U.S. soils and
common items such as fertilizers and building materials. Appendix L provides an analysis of the
major contributors to the doses estimated in the ISCORS survey, for the selected sludge
management scenarios where radiation exposure could potentially be a concern.  Section 3.4
summarizes the results of the ISCORS survey and ISCORS Dose Assessment (ISCORS 2003b).

3.3.2    Radiation Exposure Due to POTW Operations

Based on what is known about the potential for reconcentration at POTWs, possible sources of
radiation exposure would be at sludge processing or handling areas at the POTW and at off-site
locations where the sewage sludge or ash is disposed or used. People most likely to be exposed
to elevated levels of radioactive materials would be sewage sludge or ash handling personnel at
the POTW or members of the public residing on former land application sites, where sludge had
been applied for many years. Three primary ways for these people to be exposed to radiation
associated with POTW operations are inhalation, ingestion, and direct exposure (see Figure 3.2).

Inhalation of alpha- or beta-emitting radioactive materials is a concern because radioactive
material taken into the body results in radiation doses to internal organs and tissues (e.g., lining
of the lungs).  POTW workers could inhale radioactively contaminated dust during ash or sludge
handling operations. The drier the material, the more likely it could be resuspended into the air
when it is handled. POTW workers can also inhale radon and its progeny in both wet and dry
conditions.  Measures taken by POTW workers to avoid inhalation of biological  pathogens and
chemically toxic materials in sewage sludge and ash dust may effectively reduce the possible
exposure to radioactive materials. Members of the public could also inhale contaminated dust
blown from disposal or land application sites or dust from handling sewage sludge products
made available for public use.

Ingestion of alpha- or beta-emitting radioactive materials is a concern for the same reason as
inhalation.  It may occur when food crops are grown on areas where sewage sludge or ash has
been applied to the land as fertilizer or soil conditioner. (See Wisconsin DNR for more
information on plant uptake from sludge-amended soils.)  Ingestion could also occur when the
materials migrate into the ground water or surface waters used as drinking water sources. POTW
workers could ingest radioactive materials if they fail to observe good sanitary practices, such as
washing their hands before eating after handling sewage sludge or ash. (The ISCORS survey did
not measure uptake in food crops grown on sludge amended soils. It also did not measure direct
gamma exposure to POTW workers.  These potential pathways were considered, however, in the
ISCORS dose modeling project.)
ISCORS Technical Report 2004-04                3-12                          Final, February 2005

-------
Table 3.3    Summary of Concentrations of Radioactivity in Sewage Sludge and
            Ash from AMSA Survey and ISCORS Survey (pCi/g)
Radio-
nuclide
gross alpha
gross beta
H-3*
Be-7
C-14*
Na-22
K-40
Cr-51
Mn-54
Co-57
Fe-59
Co-60
Zn-65
Sr-89
Sr-90
Ru-106
Ag-108m
In-Ill
Cd-109
1-125
1-131
Cs-134
Cs-137
La-138
Ce-141
Eu-152
Sm-153
Eu-154
Eu-155
Gd-153
Tl-201
AMSA1
min
nd
nd
nd

nd
nd

nd
nd

nd
nd


nd
nd
nd

nd
nd
nd

nd

nd
nd
nd

Sources:
median
7.4
15.0
1.54

nd
4.5

nd
nd

nd
nd


nd
nd
nd

2.6
nd
nd

nd

nd
nd
nd


max
80.1
61.5
50.03

0.031
60.8

0.06
0.09

0.05
nd


0.23
1.08
6.28

174.6
0.08
0.37

0.1

0.13
2.82
2.24

ISCORS
Survey1
min
nd
nd
nd
nd

nd
nd

nd
nd
nd
nd
nd
nd

nd

nd
nd
nd
nd
nd
nd
nd
nd


nd

max
178
140
8
30
3

26
35

0.26
0.4
5.1
0.06
300
9.4

3.6

40
840
0.04
3.6
0.07
0.016
27
21


241
Radio-
nuclide
Tl-202
Tl-208
Pb-210
Bi-212
Bi-214
Pb-212
Pb-214
Rn-219
Ra-223
Ra-224
Ra-226
Ra-228
Ac-227
Ac-228
Th-227
Th-228
Th-230
Th-232
Th-234
Pa-231
Pa-234m
U-234
U-235
U-238
Np-237
Pu-238
Pu-239
Am-241
Am-243
Cm-243

AMSA1
min
nd
nd
0.12
0.08
0.14



nd

nd
nd




nd


nd

nd

nd
nd
nd


median
0.16
0.47
0.66
0.48
0.71



1.74

nd
1.30




nd


nd

nd

nd
nd
nd


max
2.08
11.48
39.1
7.3
46.48



118.12

3.86
51.08




1.34


0.93

1.97

0.58
1.27
1.41

ISCORS
Survey1
min
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd
nd


nd
nd
nd
nd
nd

nd

nd

nd
nd
nd




max
1.53
13.5
13
15.7
16
15
17
0.4
0.8
12
47
38


1.1
14
2.6
1.7
80

77
91
3.4
74
0.19
0.17
2.5




AMSA data, for 55 POTWs, from NBP (1999); ISCORS Data from ISCORS (2003)
1 nd, not detected






* pCi/g, wet weight
ISCORS Technical Report 2004-04
3-13
Final, February 2005

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  Table 3.4      Survey Concentration  Ranges  and Typical U.S. Background
                     Concentrations of Radionuclides in Soil,  Fertilizer, and Common
                     Building Materials (All  values are in pCi/g-dry weight)
Radio-
nuclide
Bi-212
Bi-214
Cs-137
K-40*
Pa-234m*
Pb-212*
Pb-214*
Ra-223*
Ra-224*
Ra-226*
Ra-228*
Th-227*
Th-228*
Th-230*
Th-232*
Th-234*
Tl-208*
U-234*
U-235*8
U-238*
Soil1
0.1-3.5
0.1-3.8
0.1-0.25
2.7-19
0.1-3.8
0.1-3.5
0.1-3.8
<0.1-0.2
0.1-3.5
0.1-3.8
0.1-3.5
<0.1-0.2
0.1-3.5
0.1-3.8
0.1-3.5
0.1-3.8
0.1-3.5
0.1-3.8
<0. 1-0.2
0.1-3.8
Phosphate
Fertilizer3
0.1-4.6
4.0-140
NDA6
32-1607
4.0-140
0.1-4.6
4.0-140
0.2-6.6
0.1-4.6
0.1-24
0.1-4.6
0.2-6.6
0.1-4.6
4.0-140
0.1-4.6
4.0-140
0.1-4.6
4.0-140
0.2-6.6
4.0-140
Building
Materials3
0.1-3.7
2.5-5.04
NDA
0.8-30
0.2-5.04
0.1-3.7
0.2-5.0
0.1-0.24
0.1-3.72
0.1-3.5
0.1-3.71
0.1-0.2
0.1-3.7
0.2-5.0
0.1-3.71
0.2-5.0
0.1-3.7
0.2-5.0
0.1-0.2
0.2-5.04
Sludge
Concentrations3
0.1-13
0.04-16
0-3.6
0.3-26
0-27
0-15
0.06-17
0.06-0.09
0.2-12
0-47
0.14-38
0-0.5
0.07-9
0.09-1.7
0.02-1.6
0-23
0.02-4.8
0.18-44
0-3.1
0.18-26
Ash
Concentrations3
0.3-16
0.62-16
0-0.37
7.4-22
1-77
0.36-15
0.61-16
0.1-0.8
0.4-4.9
0-22
0.65-30
0.02-1.1
0.4-14
0.3-2.6
0.22-1.7
1-80
0.11-14
1.2-91
0.03-3.4
0.8-74
Notes:

The curie (Ci), or fractions of a curie (e.g. picocurie), is the unit for expressing a quantity of radioactivity.  The unit normally used to describe
the concentrations of radioactivity in the environment is picocuries per gram (pCi/g).

1   Tykva, R. and J. Sabol.  "Low-Level Environmental Radioactivity-Sources and Evaluation." Technomic Publishing Company, Inc.,:
    Lancaster, Pennsylvania. 1995. This reference is the source of data for concentrations of radionuclides in soil and building materials
    except for the concentrations of U-238, U-235, and Cs-137 that came from references 9 and 6, respectively.  The concentrations of the
    daughters or decay products of U-238, such as Th-234, Ra-226, etc., those of U-235, such as Th-227 and Ra-223, and those of Th-232 are
    set equal to those of their respective parent radionuclides by assuming that the daughters are in secular radioactive equilibrium with the
    parent radionuclides.

2   Source for data on fertilizers: National Council on Radiation Protection and Measurements (NCRP). NCRP Report No. 95, "Radiation
    Exposure of the U.S. Population from Consumer Products and Miscellaneous Sources."  pp. 24-32. 1987. This is the source of data for the
    concentrations of radionuclides in phosphate fertilizers (not typical blended fertilizers) except for the concentration of K-40 in phosphate
    fertilizers) which came from the reference in note 8. The concentrations of typical blended commercial fertilizers would be 10% to 50% of
    these values.

3   A value zero as the lower boundary of the range  occurs when a very low concentration is rounded to reflect the same number of decimal
    places as the two sigma laboratory uncertainty. Non-detected values are not included in this range.

4   Eisenbud, M. and T. Gesell. "Environmental Radioactivity." Fourth Edition, Academic Press: New York, New York.  1997.

5   Cs-137 concentration range in soil obtained from Figure 4-4, p. 94 of NCRP Report No. 50, "Environmental Radiation Measurements."
    1976.

6   NDA, no data available.

7   Source for data on K-40 in fertilizer:  S. Cohen and Associates. "Final Draft NORM Waste Characterization." EPA Contract No.
    68D20155, WANo.5-09, pp. B-3-1 to B-3-24.  1997.

8   Values for U-235 in soil, fertilizer and building materials were based on the concentrations of U-238 in the same materials and the natural
    ratio of U-235 to U-238.

*   Naturally-occurring radionuclide: All concentrations are expressed in pCi/g dry, unless noted; 1 pCi = 0.037 Bq.
ISCORS Technical Report 2004-04
3-14
Final, February 2005

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                                                             Waste
                                                          Generator
   Worker
   Exposure
                                          General Public
                                    Worker
                                   Exposure
Figure 3.2   Primary Pathways for Radiation Exposure due to POTW Operations

Measures taken to limit the potential ingestion of heavy metals at land application sites would
help to reduce possible exposure to radioactive materials.  Similarly, measures taken by POTW
workers to avoid ingestion of pathogen-containing materials would serve to prevent ingestion of
radioactive materials.

Radioactive materials that emit gamma radiation are of concern because the gamma rays pose an
external radiation exposure hazard.  Because gamma rays can pass through common construction
materials,  the distance between the radioactive material and the person is a factor in the amount
of exposure the person receives.

POTW workers most likely to receive direct exposure are workers that handle sewage sludge and
ash, or work in areas of elevated indoor radon. Farmers and other members of the public who
use sewage sludge products or ash as fertilizer or soil conditioners could receive direct exposure
to gamma radiation if these materials are present. The exposure would be from the ground or
from concentrations of biosolids in piles, or from contact radiation from dust particles on clothes
or skin.
ISCORS Technical Report 2004-04
3-15
Final, February 2005

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3.3.3    What Are the Average Radiation Doses from All Sources?
          How Do Doses from Sewage Sludge and Ash Compare?

Almost everything, including people, contains some radioactive material. Naturally occurring
radioactive materials are found in the earth, in the materials used to build our homes, and in the
food and water we ingest.  Even the air we breathe contains some radioactive gases and particles.
People are exposed to radiation on a daily basis from both natural and man-made origins.

Human exposure to radiation sources is derived primarily from background natural radiation;
however, a person's occupation, geographic location, time  spent outdoors, need for diagnostic
medical treatments and testing, time spent traveling in airplanes, and other activities can
determine the relative contributions of natural, man-made,  and global fallout sources.  On the
average, 80 percent of human exposure to radiation comes  from natural sources: radon gas, the
human body, outer space, rocks, and soil. The remaining twenty percent comes from man-made
radiation sources, primarily X-rays.  Diagnostic medical and dental X-rays,  radiation treatment
and other applications of nuclear medicine contribute approximately  10 percent to 15 percent of
the average annual human dose.  Certain consumer products (television sets and other electrical
appliances, smoke detectors, building materials and tobacco products) and to a lesser extent,
airport and other types of inspection equipment, contribute approximately three to five percent of
the average radiation  dose.

It is estimated that less than one percent of the average annual dose to humans from background
radiation is a result of global fallout.  Global fallout results from nuclear accidents (e.g.,
Chernobyl) and from  nuclear weapons testing during the 1940s to 1960s. Although
above-ground testing  ceased in the United States in 1963, radiation remaining in the atmosphere
continues to account for a residual level of background human exposure.

The average radiation dose to an individual in the United States is about 360 mrem/yr.  (The term
"dose" and other background information on radioactivity are described in Appendix A.)
Typical values for annual exposure to radiation within the United States are summarized in
Table 3.5.

Terrestrial radiation comes from radioactive material that is naturally occurring in the
environment.  Radon  occurs in the environment and is listed separately in Table 3.5 because of
radon's significant contribution to radiation exposure (see also Figure 3.1).  Most of the radon
dose comes from indoor exposure in homes, schools, and workplaces. The reader is referred
back to the map in Figure 1.1 for average indoor air concentrations of radon in the US, and also
http://www.epa.gov/radon for more information. Cosmic radiation comes from outer space and
some of it penetrates through the atmosphere covering the earth. The amount of cosmic radiation
will vary depending on the altitude  and latitude where one  lives. Internal radiation comes
primarily from ingested natural radioactive substances, such as  potassium-40.

As demonstrated by the ranges shown in Table 3.5, radiation exposure can vary greatly, as the
various factors that contribute to total exposure are not constant from location to location, and an
individual's lifestyle and daily activities vary this amount.  For example, the atmosphere serves
as a shield against cosmic radiation; therefore, dose increases with altitude.  The dose at an
altitude of one mile at Denver (60 mrem/yr) is about double that at sea level (30 mrem/yr). Also,

ISCORS Technical Report 2004-04                3-16                          Final, February 2005

-------
a flight on a commercial airliner increases an individual's dose from cosmic gamma rays about
1 mrem for each cross-country flight.

 Table 3.5    Average Annual Exposure to Radiation
Source of Radiation
Average. Exposure
(mrem/yr)
Typical Range of
Variability (mrem/yr)
Natural Sources
Terrestrial
Radon
Cosmic
Internal
30
200
30
40
10-80
30-820
30-80
20-100
Man-Made Sources
Medical
Consumer products
Other
(Nuclear fuel cycle and occupational)
Total
50
10
1
360



90-1080
Sources:
NCRP 1987a, for average exposure values; Huffert et al. 1994, and Fisher 2003 for ranges of variability.
Dose rates from terrestrial sources vary from about 10 mrem/yr to 80 mrem/yr across the United
States. The major sources in the ground are potassium, thorium, uranium, and uranium progeny.
The higher doses are associated with uranium deposits in the Colorado Plateau (Figure 3.3),
granitic deposits in New England, and phosphate deposits in Florida (Figure 3.4).  The lowest
rates are the sandy soils of the Atlantic and Gulf coastal plains. Annual doses for individuals
living in brick homes may increase up to 10 mrem/yr due to naturally-occurring thorium,
uranium, and  radium found in clays often used to make bricks.
ISCORS Technical Report 2004-04
3-17
Final, February 2005

-------
 Hawaii
Figure 3.3    Uranium Deposits in the United States.  Reference DOE (1977)
                 LEGEND

               Phospnoie aepont
                 Central
                 Florida one
                 Southern Eitensicx"
Figure 3.4    Major Phosphate Deposits in the United States with Significant Uranium
              Content
ISCORS Technical Report 2004-04
3-18
Final, February 2005

-------
The principal naturally-occurring radionuclides in food are potassium-40 (a common example is
bananas) and radium-226 (e.g., in brazil nuts). Radium in water, particularly ground water,
varies across the United States.  According to a U.S. Geological Survey/Environmental
Protection Agency report (USGS 1998), "Radium is present in higher concentrations in some
States, such as the north-central States, including southern Minnesota, Wisconsin, northern
Illinois, Iowa and Missouri, and southeastern States from Georgia to New Jersey."

Radiation doses at POTWs are generally insignificant compared to background radiation under
most conditions. However, under conditions at POTWs where elevated levels of radionuclides
have been detected, there is the possibility that doses to POTW workers and to the general public
could be of concern. Previous studies attempting to  quantify these doses, however, have failed to
measure actual exposures that would indicate a potential health risk. For example, the NRC
conducted a study to estimate maximum radiation exposures to POTW workers and others who
could be affected by low levels of man-made radioactivity in wastewater (Kennedy et al. 1992).
The estimates of these hypothetical exposures to workers range from zero to a dose roughly
equal to natural  background levels.  The study, which did not consider NORM/TENORM, used
scenarios,  assumptions, and parameter values generally selected in a manner to produce
prudently conservative estimates of individual radiation doses. However, the quantities of
radionuclides released into the sewer systems were assumed to be the maximum allowed under
NRC regulations. Thus, the calculations were not intended to be based on realistic or prudently
conservative conditions at POTWs, but based on maximized releases to sewer systems.

3.4    SUMMARY OF RESULTS OF ISCORS SURVEY

Radioactive materials are a natural part of the environment and a byproduct of human activity.
Naturally-occurring and man-made radioactive materials may enter POTWs by water infiltration
or inflow,  domestic discharges, and permitted or accidental discharges.  There are numerous
factors to consider when determining the sources of radioactive material and whether
radionuclides are present in sewage sludge or ash at levels that are of any concern to worker
safely or public  health.

The ISCORS Survey (ISCORS 2003) results provide an estimate of the range of concentrations
of radionuclides that may be present in sewage sludge and ash. The ISCORS Dose Assessment
project (ISCORS 2003b) provides a means for estimating potential doses associated with these
levels of radionuclides under various sludge management scenarios. Table 3.6 combines the
dose modeling results with the Survey measurements, and makes it clear that while some
scenarios and radionuclides give rise to very low doses, there are other radionuclide-scenario
combinations that may be a significant increment over background.

Based on results of the ISCORS Survey and Dose Assessment, the tables in Appendix L show
the radionuclides that may be most likely to be of concern in terms of potential doses to members
of the public and to POTW workers. From the ISCORS Dose Assessment, the scenarios most
likely to be of concern are the Onsite Resident and the POTW Worker Loading scenarios. The
Appendix L tables show the radionuclide, the 95th percentile concentration and the maximum
concentration measured in the ISCORS survey, the percent of samples in which the radionuclide
was detected, probable source of the radionuclide, and the most significant scenario, based on the
95th percentile concentration.

ISCORS Technical Report 2004-04                3-19                         Final, February 2005

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The radionuclides listed in these tables are only those thought most significant based on the
ISCORS Survey results and the ISCORS Dose Assessment methodology.  The analysis included
in Appendix L may be useful as an indication for individual POTWs of which radionuclides
should be considered initially. However, concentrations and exposure scenarios at an individual
POTW will be different from those of the ISCORS Survey and Dose Assessment. Thus, POTW
operators should not eliminate from further consideration any radionuclide that might be
identified within its service area, as a result of surveying licensees or identifying industries or
natural sources of radionuclides (see Chapter 5). Also, a site-specific evaluation may be required
(see Chapter 6). In particular, there are specific radionuclides listed in the Appendix L tables
that have resulted in contamination at certain POTWs (see Chapter 1), such as Co-60, Am-241,
U-234, andU-238.

The basic conclusions of the ISCORS Survey and Dose Assessment project are as follows:

•  None of the non-POTW scenarios shows a significant current widespread threat to public
   health. For instance, the scenarios with the largest potential critical groups—the Nearby
   Town and the  Incinerator Neighbor—show relatively small estimated doses, as does the
   Landfill Neighbor.  The landfill neighbor scenario assumes that institutional and engineering
   controls (deed restrictions and cap) remain intact past the required 30-year monitoring
   period.  There is a possibility, however, that site restrictions would not be followed. If an
   intruder were to build a house on either a surface impoundment or municipal solid waste
   landfill where sewage sludge or ash was buried, doses could be significantly higher.  This
   scenario was not considered plausible by ISCORS, so it  was not modeled.

•  If agricultural  land application is carried out for a long time into the future, then the potential
   exists for future radiation exposure primarily due to radon, if the land application site is
   converted to residential use.  This is illustrated in the 50 and 100 year application  sub-
   scenarios of the Onsite Resident. Some non-radon doses could be above certain dose criteria
   (see Table 3.6) even at 20 years of application. However, the levels of radioactive materials
   detected in sewage sludge and ash in the ISCORS survey and as calculated in the dose
   assessment indicate that, for most POTWs, radiation exposure to the general public through
   the use of sludge as a soil amendment for growing food  crops is very low and consequently,
   is not likely to be a concern.

•  In specific cases of very high concentrations of radioactive materials (e.g., levels above
   95%), there is the potential for localized radiation exposure.

•  Within the POTW, little exposure is expected for sampling and transport. Only when
   workers are in the same room with  large quantities of sludge (e.g., for storage or loading) is
   there the potential for significant exposure, predominantly due to radon.  In this case, the
   degree of exposure is likely to depend highly on the configuration of the POTW in terms of
   room sizes, ventilation, and so forth, as well as the duration of exposure of the worker.

•  While ISCORS believes that the seven scenarios in Table 3.6  represent the most likely
   exposures from sewage sludge, there are numerous other scenarios that may be plausible
   considering site specific conditions, such as a future farm field worker or a landfill intruder
   (discussed above), and which may warrant investigation. In such cases, POTW operators are
   encouraged to seek advice from health physics consultants for site specific modeling.
ISCORS Technical Report 2004-04               3-20                          Final, February 2005

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The highest doses computed for the Onsite Resident and the POTW Worker are notable; but
several important factors account for these elevated values, suggesting that typical exposures
would not necessarily approach such levels:

•  The exposure scenarios are somewhat conservative; in addition, the doses mentioned above
   are upper-end percentile values.

•  The doses for the Onsite Resident for 50- or 100-years of annual application would be
   significant, but very few farms in the country, so far, have used sewage sludge for even
   20 years.

•  The highest doses are generally attributable to the indoor radon pathway.  For the Onsite
   Resident, the 95-percentile sample doses tend to be a factor of 6.5 higher than the
   corresponding median (50th-percentile) sample doses, regardless of the number of years of
   application, simply because of the difference in the concentration of radium in the sludge
   (13 pCi/g versus 2 pCi/g). Both for the Onsite Resident and the POTW Worker, exposures
   can be decreased significantly through the use of readily available radon testing and
   mitigation technologies.

Processes at POTWs can reconcentrate radioactive materials in sewage sludge and ash.  People
working with or near the sludge at the POTW,  those working at disposal sites, and users of
sludge products could be exposed to any radionuclides that reach the POTW.  Exposure could
occur from inhalation of dust, ingestion  of contaminated food, or direct exposure. Guidance on
determining whether these or other potential exposures could occur, and whether these exposures
should be a concern at a POTW, as well as suggestions on appropriate response actions, is
provided in Chapters 5-7 of this report.
ISCORS Technical Report 2004-04               3-21                          Final, February 2005

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Table 3.6    Calculated Total Peak Dose from Survey Samples: Summary
            Results With and Without Indoor Radon Contribution (mrem/year)
Scenario
S 1-Onsite Resident
S2-Recreational
User
S3-Nearby Town
S4-Landfill
S5-Incinerator
S6-Sludge
Application
Worker
S7-POTW
Workers
Subscenario
1 yr of sludge application
5 years application
20 years application
50 years application
100 years application
N/A
1 yr of sludge application
5 years application
20 years application
50 years application 2
100 years application 2
MSW — Sludge
MSW — Ash
Impoundment
N/A
1 yr of sludge application
5 years application
20 years application
50 years application
100 years application
Sampling (mrem/sample)
Transport (mrem/hr)
Loading
Median sample
(mrem/year)
TEDE
0.5
2.5
9.2
22
42
0.04
6.4e-04
2.8e-03
8.5e-03
0.017
0.029
4.6e-03
0.014
0.21
1.2
0.032
0.16
0.57
1.3
2.3
9.6e-08
4.6e-05
3. 8-17 3
TEDE
w/o Rn
0.2
1
3.4
7.2
13
-
-
-
-
-
-
1.6e-03
3.1e-03
0.062
-
-
-
-
-
-
-
l.le-05
2.7
95% sample
(mrem/year)
TEDE
o
3
14
55
130
260
0.22
3.2e-03
0.014
0.045
0.094
0.17
0.027
0.041
1.2
7.7
0.15
0.77
o
J
7.4
15
4.9e-07
1.9e-04
17-70 3
TEDE
w/o Rn
1
4.9
16
37
69
-
-
-
-
-
-
0.01
0.014
0.36
-
-
-
-
-
-
-
5.6e-05
13
Dominant Radionuclide(s)
[pathways]
Ra-226 [indoor radon]1
Ra-226 [indoor radon] :
Ra-226 [indoor radon] l
Ra-226 [indoor radon] :
Ra-226 [indoor radon] l
Ra-226 [external]
Ra-226 [outdoor radon]
Ra-226 [outdoor radon]
Ra-226 [outdoor radon]
Ra-226 [outdoor radon]
Ra-226 [outdoor radon]
Ra-226 [indoor radon] l
Ra-226 [indoor radon] :
Ra-226 [indoor radon] l
multiple [multiple]
Ra-226 [external]
Ra-226 [external]
Ra-226 [external]
Ra-226 [external]
Ra-226 [external]
Ra-226 [external]
Th-228 [indoor radon, external] :
Ra-226, Th-228 [indoor radon] 1
Notes:
All values rounded to two significant figures. 95% DSRs are used in all total peak dose calculations.
The symbol "-" denotes that indoor radon was not separately calculated. N/A denotes Not Applicable. MSW
denotes Municipal Solid Waste.
1 The dominant radionuclide applies to doses that include radon. However, radon is typically controlled by
concentration level (e.g., pCi/L or WL) and not by dose. The recommendations in Chapter 6 of this report
use EPA's radon guidelines (4 pCi/L or 0.02 WL) as a metric for actions relating to indoor radon.
2 There are very few land application sites in the country that are known to have applied sewage sludge
annually for more than 20 years; the 50- and 100-year computations are included for the information of
POTW operators in their consideration of future sludge management practices.
3 Range represent results from the nine combinations of air exchange rate and room height (see Section 1.2).
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4 WHAT ARE THE RELEVANT REGULATORY AGENCIES?
   WHAT ARE THEY DOING?

The regulatory framework for radioactive materials in wastewater is somewhat complex.  There
are many levels of authority and types of requirements. Federal Guidance on radiation exposure
to workers and the public is prepared under the authority of the EPA as issued by the President.
Regulations are issued and enforced by various agencies at different levels of government,
depending upon the type of radioactive material and the agreements arranged.  Information
provided in this section includes only those aspects most germane to the types of materials that
may enter wastewater and therefore affect POTW operations.

The primary division of the regulatory framework is based on the origin of radioactive material.
In general, man-made radioactive materials are regulated differently than NORM and TENORM.

Radioactive materials consisting of source, byproduct, and special nuclear material (see
Appendix G for definitions of these materials) are subject to the provisions of the Atomic Energy
Act (AEA). Radioactive materials used in the commercial and private sector are subject to the
rules of the NRC.  When these materials are in the defense sector in weapons development
operations, they are under the control of the Department of Energy (DOE). However, DOE also
regulates TENORM and accelerator produced radioactive material under AEA authority.  This
guidance focuses on the NRC regulations, rather than the DOE requirements, primarily because
DOE's requirements are generally consistent with NRC's, and only  apply to DOE's nuclear
facilities.

The AEA allows the NRC to establish formal agreements with  States, granting the States with
authority to develop and oversee the implementation of specific regulations regarding use and
possession of source, byproduct and special nuclear materials generated or used at these
facilities. States with such an agreement, i.e., Agreement States, are required to maintain a
radiation protection program that is adequate to protect public health and safety and is
compatible with that of the NRC. A current map showing Agreement States is provided in
Appendix B. Information on the relevant agencies that are designated under the AEA with the
authority to develop and oversee regulations for commercial use of radioactive materials is listed
in Appendix E.

The lead Federal agency in the regulation of NORM and TENORM is EPA. The DOE also
regulates NARM at DOE facilities.  In addition, some State and local authorities also regulate
various aspects of the materials discussed above. Other radioactive materials are generally
regulated by the States.  The Department of Labor's Occupational Safety and Health
Administration (OSHA) regulates workplace safety and health, including exposure to hazardous
or toxic materials,  and radiation. More detailed information on the role and regulations of the
NRC, Agreement States, EPA, State agencies, and local authorities, as well as ISCORS, is
provided in the following sections.
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4.1    U.S. NUCLEAR REGULATORY COMMISSION (NRC) AND
       AGREEMENT STATES

NRC and Agreement States regulate the possession, use, and disposal of certain radioactive
materials, and also develop and implement guidance and requirements governing licensed
activities, inspection and enforcement activities to ensure compliance with the requirements.
The primary radiation protection regulations for AEA materials regulated by the NRC are
contained in the Code of Federal Regulations (CFR), Title 10, Part 20. Section 20.1301 of these
regulations contains the dose limit for members of the public, which is 100 mrem/year from
operations of an NRC-licensed facility. Subpart E of Part 20 provides radiological criteria for
termination of NRC licenses, including, in Section 20.1402, a dose criterion of 25 mrem/year for
termination of a license for unrestricted use. Section 20.2003 describes the limits on sewer
disposal for radioactive materials. This regulation sets limits on the concentration of radioactive
material that may be discharged to the sewer in one month and the total annual quantity of
discharge. In 1991, the NRC revised the regulatory  provisions that limit releases to the sewer,
due to the discovery of problems with metallic radioactive materials disposed of as finely
dispersed materials.  The NRC regulations now require that all radioactive materials disposed to
the sewer be readily soluble (or be readily dispersible biological material) in water.  The
Agreement States have adopted compatible regulations.

With some  specified exceptions, any  activity involving source, byproduct, and special nuclear
material must be conducted under a license issued by the NRC or an Agreement State.  The
exempt activities are described in NRC's 10 CFR Part 30, Part 40, and other Parts. For example,
exemptions from specific licensing include some consumer products, such as smoke detectors
and luminous watches.  While medical facilities and hospitals may be required to obtain a
license, individuals undergoing medical procedures with radioactive materials are not subject to
these regulations.

Licenses are issued to licensees only  after NRC or the Agreement State is satisfied that the
licensee has the qualified staff, equipment, procedures, instrumentation, training programs, and
management oversight deemed necessary to operate the proposed program in a safe manner and
within the restrictions specified in the license.  Both NRC and Agreement States monitor their
licensees by means of periodic inspections. The frequency of inspections depends on the type of
license issued to the licensee and is based on risk. The frequency will vary from annual
inspections for complex licensees, such as  hospitals with a broad license, radiopharmaceutical
companies, and other large users of byproduct materials, to inspections once every 3-5 years for
small or simple licensees who may use only one small radioactive source in a routine and well-
established application. The license may be suspended or revoked if NRC or the Agreement
State finds that the licensee's operation does not meet requirements of the regulations, conditions
of the license, and operating procedures. Additional information about NRC and Agreement
State licensing and enforcement is provided in Appendix I.
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4.2    U.S. DEPARTMENT OF ENERGY (DOE)

Under the Atomic Energy Act, the Department of Energy Organization Act (DO A), and other
related Federal statutes, DOE has been assigned broad responsibility for protection of the public,
the environment, and real or personal property from radiological hazards associated with its
research, development, weapons production, and other activities. Operators of DOE facilities are
responsible for compliance with regulations and internal directives that contain specific
requirements for managing radioactive materials. For a summary of these directives, consult
"The Long-term Control of Property: Overview of Requirements in Orders DOE 450.1 and
5400.5", which can be obtained from DOE's Office of Environment, Safety and Health website
(http//:tis.eh.doe.gov/oepa/) under the section entitled "Policy and Guidance-Radiation
Protection." DOE also implements radiation worker protection requirements at its facilities,
under 10 CFR Part 83 5.

DOE internal directives restrict the release of radioactive material to the environment by setting
an annual general public dose limit based on all pathways of potential exposure. Controls are in
place at each DOE nuclear facility to ensure that releases of radioactivity from all sources  are
monitored so that general public exposures are well below the general public dose limit. Any
release of liquid waste that contains radionuclides that meets the protective levels established in
DOE internal directives is considered a "Federally permitted release," and as such, is subject to
treatment by a process selected through the Best Available Treatment procedure, and is also
subject to the As Low As Reasonably Achievable standard. Although Federally permitted
releases to sewage systems are not subject to prior notice or approval by the POTW operator,
DOE internal directives do require that radioactivity levels be controlled so that a local POTW's
wastewater treatment and sludge management processes are not disrupted.

4.3    U.S. ENVIRONMENTAL PROTECTION AGENCY (EPA)

EPA has limited authority to regulate radioactive materials. Under the Atomic Energy Act of
1954 as amended (AEA) and the Reorganization Plan No.3 of 1970, EPA has authority to
establish generally applicable environmental standards for the protection of the general
environment from radioactive material regulated under the AEA. 42 U.S.C. § 220l(b);
Reorganization Plan No.3 of 1970, § 2(a)(6).  (Under the Reorganization Plan, "standards" mean
limits on radiation exposure or levels, or concentrations or quantities of radioactive material, in
the general environment outside the boundaries of locations under the control of persons
possessing or using radioactive material.)  In addition, the AEA directs EPA to advise the
President and Federal agencies in the formulation of radiation standards. 40 U.S.C. § 202l(h).
The Atomic Energy Act and the Reorganization Plan do not provide implementation and
enforcement authority for EPA. Rather implementation and enforcement of EPA's generally
applicable standards are the responsibility of other Federal agencies.

4.3.1     Role in Regulating Facilities That May Discharge to POTWs

The Clean Water Act (CWA) prohibits the addition of any pollutant to navigable waters from a
point source except in compliance with provisions of the CWA. In addition, the CWA requires
EPA to establish pretreatment standards for certain pollutants that are introduced into POTWs.


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EPA must establish pretreatment standards for pollutants that are not susceptible to treatment by
the POTWs—the pollutant "passes through" the POTW—or these pollutants interfere with
POTW operations (33 U.S.C. 1317(b)).  Pretreatment standards are implemented through local
POTW programs that are required conditions of POTW discharge permits (Sections 402(a)(3)
and (b)(8)).  Indirect users of POTWs (for example, facilities that introduce pollutants into
POTWs through sewers or by hauling waste to POTWs) must comply with pretreatment
standards.

EPA has established two types of national pretreatment standards under section 307(b). First,
EPA has promulgated general and specific prohibitions on the introduction of pollutants into a
POTW that apply to each user regardless of the applicability of other national standards.  These
standards prohibit the introduction of any pollutant that will cause pass through and interference
and, among other things, the introduction of pollutants that will obstruct POTW flow or
pollutants that will cause acute worker health or safety problems.  Second, EPA has established
"categorical" pretreatment standards.  Categorical standards specify quantities or concentrations
of pollutants that may be introduced by industrial users in specific industrial categories
(40 CFR 403.5 and 403.6).

While the Clean Water Act (CWA) 33 U.S.C. 1251, et seq., defines "pollutant" to include
radioactive material (see 33 U.S.C. § 1362(6)), it is the EPA's longstanding position that EPA
has no authority under the CWA to regulate radioactive materials regulated  under the AEA.  The
AEA regulates radioactive source material such  as uranium and thorium or ores containing them,
special nuclear material such as plutonium or enriched uranium, or byproduct radioactive
material such as the tailings or wastes produced  by the extraction of uranium or thorium
(42 U.S.C. § 2014(e),(z), and (aa)).
 Box 4.1       EPA Authority
 As discussed above, EPA has no authority to regulate radioactive "source material, special
 nuclear material, and byproduct material" in sewage sludge. However, EPA has authority
 under the CWA to regulate radioactive materials that are not source, special nuclear, or
 byproduct material regulated under the AEA (e.g., TENORM).
EPA also regulates the discharges of waste material from contaminated facilities cleaned up
under the Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA). If such facilities discharge to a sanitary sewer, EPA has the authority to regulate the
limits for both man-made radioactive materials and TENORM.  EPA may also grant authority to
a State to serve as the regulator of CERCLA cleanups.

EPA regulates the management of hazardous industrial waste, pursuant to the Resource
Conservation and Recovery Act (RCRA). EPA and NRC are currently exploring the conditions
under which RCRA hazardous waste disposal facilities could more routinely accept low-activity
radioactive materials.

EPA also establishes radiation-related standards in other areas that may indirectly affect the
consideration of both man-made radioactive materials and TENORM at a POTW.  For example,

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under the Clean Air Act (CAA) EPA may limit radionuclide releases to the air from facilities
(e.g., elemental phosphorous plants). These facilities may generate waste products containing
radioactive materials that could enter the sanitary sewer system.

Another radiation-related standard that may indirectly affect POTWs includes EPA's standards
for radionuclides in drinking water under the Safe Drinking Water Act (SDWA). These
regulations, encompassing both man-made radioactive materials and TENORM, have caused
many municipalities to incorporate water treatment that removes radioactive materials from the
influent water before releasing it to the service connections. It has been noted in several
instances that municipal water treatment facilities discharged residues with elevated radioactive
material content from this process to the sanitary sewer systems. EPA is currently developing
new guidance that addresses disposal of drinking water treatment residuals and filters.  The
guidance will provide responses to frequently asked questions, information on water treatment
technologies and associated wastes,  applicable waste disposal options, a review of existing
Federal and State laws and  regulations governing those wastes, a review of occupational
radiation health and safety practices, and a list of licensed disposal facilities.

4.3.2    Role in Regulating Radon  and Indoor Air

Radon and indoor air quality information and guidance are provided by the U.S. EPA's Office of
Radiation and Indoor Air (ORIA). ORIA develops national programs, technical policies, and
guidances for controlling radon and  indoor air pollution exposure.  Its concerns for indoor air
include exposures to smoke, molds,  mildew, and indoor radon. Under the  Radon Gas and Indoor
Air Quality Research Act (1986) and Indoor Radon Abatement Act (1988), as well as authorities
of the Clean Air Act, EPA has developed guidance rather than regulations  for control of radon in
buildings and schools.  (See Table 6.1.)

Since the mid-1980s, the United States has made significant progress in reducing the risk from
exposure to radon.  This progress is  the result of a long-term effort between EPA, citizens,
non-profit organizations, State and local governments, the business community, and other
Federal agencies working together.  More adult Americans are knowledgeable about radon than
at any time since the mid-1980s, when radon became a National health concern. Since the
mid-1980s, about 18 million homes  have been tested for radon and about 700,000 of them have
been mitigated. Approximately 1.8  million new homes have been built with radon-resistant
features since 1990.

4.3.3    Role in Regulating POTWs

EPA regulates  POTWs in several ways.  As discussed above, the CWA prohibits the discharge of
any pollutant to navigable waters except in compliance with its requirements.  A POTW that
wishes to discharge pollutants into the waters of the United States may achieve such compliance
by obtaining a  National Pollutant Discharge Elimination System (NPDES) permit from EPA.
Permits are issued to dischargers (including both industries and POTWs), specifying the
discharge conditions and monitoring requirements to ensure certain conditions are met. NPDES
permits prescribe the terms under which parties may discharge pollutants.  Under the CWA, EPA
may authorize  States to administer their own permit program under State law so long as the
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program meets certain requirements prescribed by the Act.  EPA suspends issuance of its own
NPDES permits if EPA approves the State program.

As explained above, EPA also implements a CWA National Pretreatment Program. Under this
program, facilities discharging a significant amount of wastewater to the POTW must limit their
discharges of specific pollutants to the sanitary sewers. By limiting the discharge of these
pollutants, the sewage treatment plants receiving the discharges are better able to meet their
NPDES permit conditions, to protect the treatment plant workers from these pollutants and to
keep pollutants in the sewage sludge produced by these plants below specified limits.

EPA also regulates the use and disposal of sewage sludge produced by POTWs.  The relevant
regulations are found in 40 CFR Parts 257 and 503, but at this time, do not address radioactive
material in sewage sludge which EPA may have authority to regulate (i.e., the non-AEA
radioactive components).  Under the Resource Conservation and Recovery Act (RCRA), EPA
cannot directly regulate as hazardous waste radioactive material that is subject to the AEA in
sewage sludge.  However, EPA could regulate the non-AEA hazardous waste components of the
sludge under RCRA.

When sewage sludge is incinerated, some radioactive material may be emitted.  EPA has no
direct authority under the Clean Air Act (CAA) to regulate the concentration of radioactive
materials in sewage sludge/ash at POTWs.  However, radionuclides were expressly included in
the initial list of hazardous air pollutants in Part 112(b) of the CAA, and EPA has authority to
establish National Emission Standards for Hazardous Air Pollutants (NESHAPs) under Part 112
of the CAA for facilities that emit radionuclides to the ambient air.  Although EPA does not
regulate the concentration of radionuclides in  sewage sludge/ash directly under the CAA, the
measures required to control emissions of hazardous air pollutants from POTWs may indirectly
affect the concentration of radionuclides in sewage sludge.

Under the CWA, EPA determines the pollutants for which it will establish sewage sludge use
and disposal standards (i.e., 40 CFR Part 503) based on current information about the potential
for adverse consequences to human health and the environment.  Part 405(d) of the CWA
requires EPA, based on available information, to establish numerical pollutant limits for
pollutants present in sewage sludge in concentrations that may adversely affect public health and
the environment. These standards must be adequate to protect public health and the environment
from reasonably anticipated adverse effects. This authority, in combination with the Agency's
authority under AEA to establish generally applicable environmental standards for the protection
of the general environment from radioactive material and to establish NESHAPs for hazardous
air pollutants (including radionuclides) under part 112 of the CAA for facilities which emit
radionuclides to the ambient air, would appear to provide adequate authority to establish
numerical limits for any radionuclides in sewage sludge/ash for most end use and disposal
practices if deemed necessary to protect public health and the environment.

While the definition of "pollutant" in the NPDES Regulations (40 CFR 122.2) specifically
exempts radioactive materials that are regulated under the AEA as amended (42 U.S.C. 2011 et
seq.), the Pretreatment Regulations (40 CFR Part 403) prohibit "interference," which includes a
discharge which "inhibits or disrupts the POTW, its treatment processes or operations, or its
sludge processes, use or disposal" [40 CFR 403.3(i)]. Significant industrial users discharging to

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POTWs are regulated through control mechanisms (typically permits) with specific components
issued by the POTWs (or States) under Pretreatment Programs that are approved by EPA.

4.4    OCCUPATIONAL SAFETY AND HEALTH  ADMINISTRATION
       (OSHA)

The Occupational Safety and Health Administration (OSHA) developed occupational radiation
standards (see 29 CFR 1910.1096 [??]) that might apply whenever an operator becomes aware of
the presence of radiation at the facility.  Although these standards may not apply to municipal
wastewater treatment plant workers, these workers may be covered by their State's OSHA
program, requiring that all controls, monitoring, recordkeeping, and training outlined in the
OSHA standards be met.

Additional OSHA standards that may be applicable to wastewater systems include:

•  Requirements that personal protection equipment (or PPE, for the eyes, face, head, and
   extremities) such as protective clothing , respiratory  devices, and protective shields and
   barriers be provided, used, and maintained whenever processes or radiological hazards
   capable of causing injury through absorption, inhalation, or physical contact necessitate such
   equipment. There are numerous other requirements related  to the possession and use of PPE,
   including training for employees who would use the  equipment. For more information, see
   29 CFR 1910.132-136.

•  Requirements for practices and procedures to protect employees in general industry from the
   hazards of entry into permit-required confined spaces.  For more information, see 29 CFR
   1910.146.


4.5    INTERAGENCY STEERING COMMITTEE  ON RADIATION
       STANDARDS (ISCORS)

NRC and EPA formed the Interagency Steering Committee on Radiation Standards (ISCORS) in
1995 to resolve and coordinate regulatory issues associated with radiation standards. The
objectives of the committee include the following: (1) facilitate a consensus on acceptable levels
of radiation risk to the public and workers, (2) promote consistent risk assessment and risk
management approaches by setting and implementing standards for occupational and public
protection from ionizing radiation, (3) promote completeness and coherence of Federal standards
for radiation protection, and (4) identify interagency issues and coordinate their resolution.  In
addition to NRC and EPA,  ISCORS membership also includes senior managers from the
Department of Defense, the Department of Energy, the Department of Labor's Occupational
Safety and Health Administration, the Department of Transportation, the Department of
Homeland Security, and the Department of Health and Human Services. Representatives of the
Office of Management and Budget, Office of Science and Technology Policy, and the States are
observers at meetings.

ISCORS formed a Subcommittee to  conduct the ISCORS sewage survey and to develop this
POTW report. Most of the information previously available on reconcentration of radionuclides


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in sewage sludge and ash was due to unusual circumstances that triggered discovery of incidents
in the course of other POTW operations. The Subcommittee has evaluated the occurrence of
radioactive materials in sewage sludge and ash, including the sampling of sewage sludge and ash
from POTWs across the country (ISCORS, 2003) and has conducted modeling to evaluate the
dose associated with radioactive material in sewage sludge and ash (ISCORS, 2003b). These
activities were conducted to evaluate the need for future regulatory actions by individual
agencies. Some of the regulatory actions that could have been considered include the following:

•  NRC regulations that would further limit the sanitary sewer discharge of man-made
   radioactive materials.

•  EPA regulations that would further limit the discharge of NORM/TENORM through NPDES
   permits.

•  EPA regulations that would include requirements for radioactive materials in sewage
   sludge/ash use and disposal practices.

Chapters 5 and 6 of this report provide recommendations to POTW operators, based on the
ISCORS analyses, on prudent steps that may be taken to determine if there is any concern for
radiation levels present in the sewage sludge or ash.

4.6    STATE AGENCIES

In addition to the role of State agencies as NRC Agreement States, States have been active
regarding the issue of potential  radioactive contamination at POTWs.  Many States (both
Agreement and non-Agreement States) regulate radioactive material, and have promulgated
regulations regarding TENORM, in a manner similar to the regulations regarding man-made
radioactive materials. For example, some States have established licensing and inspection
requirements for users of TENORM. Other States require users of TENORM to register with the
State, rather than being issued a license.  To date, 13 States have approved regulations for
TENORM, and several States have TENORM-related guidance, or regulations for TENORM
generated in specific industries; this primarily includes the oil and gas industries and the mining
industry. Other States regulate TENORM to varying degrees through their radiation control
regulations without specific TENORM regulations (see Appendix E).  State radiation control
programs may also address the  following areas:

•  X-ray machines;

•  Licensing of radiological technologies;

•  Accelerator-produced radioactive materials;

•  Source, by-product, or small amounts of special nuclear materials (if Agreement State);

•  Radon awareness;
•  Certification programs for radon tester or mitigators;

•  Non-ionizing sources of radiation, such as radio frequency sources, lasers, and others;
•  Drinking water standards for radium, radon, and others;


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•  Cleanup of radioactively contaminated sites;
•  Monitoring around nuclear power plants;

•  Emergency response to nuclear power plants and radioactive materials incidents;
•  Regulation and guidance for occupational radiation health and safety protection;

•  Low-level radioactive waste siting; and

•  Laboratory services.

As an example, the State of New Jersey has issued, or is in the process of issuing discharge
permits for water purveyors who are treating the groundwater for radium. The two that are
currently in operation are ion exchange units that discharge backwash and regeneration water to
POTWs.  This discharge contains high concentrations of radium. Because of the size of the ion
exchange units, they accumulate greater than the licensing exempt quantity for radium.
Therefore, they were issued radioactive material licenses through the radiation protection
program. Discharge limits for licensees were applicable and were specified in the significant
industrial user permit and in the radioactive material license. Because of the uncertainty
regarding radionuclides in sewage sludge, only temporary discharge permits were issued.
Requirements are in place for monitoring the discharge periodically and the State has been
monitoring the sludge of the receiving POTWs.

Recently there have been proposals  in New Jersey for treating either the backwash/regeneration
water or the drinking water with a radium selective complexor that captures the radium and holds
it in the resin until it is disposed of at a low-level  radioactive waste disposal facility. Estimates
are that the units could operate up to three years before change out of the resin.  A radioactive
materials license would be required, but there would be no discharge of radium to the POTW.
This method has proved to be cost effective when considering the monitoring requirements on
the backwash/regeneration discharge (at least once monthly).

Other examples of State involvement in addressing radioactive contamination at POTWs include
the case studies presented in Chapter 1 (i.e., Tennessee and Oregon).  State radiation control
programs are good contacts for the POTW operator for information about radiation control.
State radiation control programs are composed of individuals who have studied radiation and
have experience with that particular State's problems.

4.7    LOCAL AUTHORITIES

The role and authority of local jurisdictions, especially POTW authorities, is one of the more
complex  of the relationships related to POTWs and radioactive material. As noted above,
significant industrial users discharging to POTWs are regulated through control mechanisms
(typically permits) with specific components issued by the POTWs (or States) under
Pretreatment Programs that are approved  by EPA. The nature of the arrangement between the
POTW and its customers will depend upon Federal, State, and local law as well as any applicable
requirements in EPA's pretreatment program (40 CFR Part 403). In some cases, there are local
permits issued to POTW users that would govern the circumstances of discharges to the POTWs.
In other cases, the arrangements are purely contractual and the relationship between the POTW


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and its users (including whether users must notify the POTW before discharging radioactive
material) would be a contract condition.

Through effective pretreatment and source control programs, POTWs have had considerable
success in reducing problems associated with industrial sources of contaminants that interfere
with the performance of treatment facilities or sewage sludge quality (EPA, 1991). As a recent
example, between 2000 and 2001, the City of Los Angeles Department of Public Works realized
a 30% reduction of sanitary sewer overflows after requiring existing restaurants to conduct best
management practices (BMPs) in existing restaurants to control the levels of fats, oils and grease
(FOG) discharged and the installation of pretreatment technology (grease interceptors) in both
existing and newly built restaurants. Existing restaurants that failed to implement the  BMPs
were also required to install the grease interceptors.  The City also instituted a pipe-cleaning
program to identify and clean problem areas, and increased its inspections of food service
establishments to reinforce the need for complying with the BMPs and technology requirements
(City of Los Angeles Press Release, April 10, 2002).

However, POTWs may not have the same authority  concerning radioactive material as they do
for any other material in influents to the POTW. This is because the U.S. Supreme Court has
held that for certain activities covered by the AEA, Federal authority preempts other regulatory
authorities whose purpose is radiation protection. See Pacific Gas & Electric Co. v. State
Energy Conservation Commission, 461 U.S. 190, 209-212 (1983).

In order to determine the true purpose of a regulation, courts will examine the legislative text,
history, and the effect of the  regulation. See Perez v. Campbell, 402 U.S. 637, 651-52 (1971). If
the purpose of a State or local government regulation is the protection of workers and the public
from the health and safety hazards of materials covered by the AEA, then the action is
preempted. See United States v. Kentucky Natural Resources & Environmental Protection
Cabinet, 252 F.3d 816, 823-824 (6th Cir.  2001); 10 CFR 8.4.  If the purpose is something other
than protection against radiation safety hazards, State and local authorities might be able to
impose limits on radioactive effluent discharges. However, the Court in English v. General
Electric, 496 U.S. 72, 84-85  (1990) held that State laws which have a direct and substantial
effect on the decisions made by nuclear facility operators regarding radiological safety levels
may be preempted regardless of their purpose.

Because preemption case law employs several subtly different tests that can only be
meaningfully applied to concrete facts, development of general guidance on the issue is difficult.
For example, see KerrMcGee Chemical Corp. v. City of West Chicago, 914 F.2d 820, 825-827
(7tn Cir. 1990) (outlining preemption principles applied by various courts in AEA cases). It is
hard to predict whether unusual  cost to the POTW caused by radioactive effluent discharges
would be a sufficient reason  to impose discharge limits greater than those permitted under
Federal law because there are no Federal cases in which: (1) the specific facts corresponded to
the scenarios faced by local POTW authorities and (2) the court decision addressed the
preemption issue.

Local POTW authorities should also be aware of two relatively recent court cases which have
addressed issues of local authority on radiation matters, but which do not provide definitive
answers. In Cleveland, Ohio, a discharger of radioactive materials was unable to obtain a

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restraining order to prevent local authorities from terminating sewer service based on the
radioactive materials in its wastewater.  The POTW's actions were supported by restraining
orders from both Federal and State courts, but a settlement of the overall case precluded either
Federal and State court from reaching a final opinion. Therefore, there remains some uncertainty
in this case.

In Santa Fe, New Mexico, a discharger has obtained a summary judgment in Federal Court,
which prevented local authorities from regulating environmental matters generally, including
radioactive discharges. However, this decision was based on interpretation of New Mexico
statutes.  The Court held that while State law authorizes local governments to construct and
operate sewage treatment plants, the regulation of environmental matters generally has not been
delegated to local authorities and may only be exercised at the State level. Interstate Nuclear
Services Corp. v. City of Santa Fe, 179 F. Supp.2d 1253,1259 (D.N.M. 2000).
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5  WHAT CAN A  POTW OPERATOR DO TO DETERMINE IF
   THERE IS  RADIOACTIVE CONTAMINATION? WHO CAN
   HELP?

Although POTWs may not be the primary regulatory authority, there are several sequential steps,
listed below, that a POTW may consider if they have concerns regarding radioactivity.  It is also
likely that the cost for each succeeding step will be more than the cost of the preceding step. The
steps include the following:

•  Determine what radioactive materials may be discharged into or otherwise enter the
   wastewater collection and treatment system.

•  Determine if monitoring or sampling for radioactive material and radon at the POTW should
   be performed.

•  Determine how a POTW operator can sample and analyze sewage sludge and ash for
   radioactive material, test and monitor for radon.

•  Estimate potential doses from radioactive material in sewage sludge and ash through
   screening calculations, and compare with existing standards or guidance.

•  Conduct a site-specific evaluation that may involve additional surveys or sampling of the
   POTW, POTW personnel, and/or use or disposal sites.

The first three steps are discussed in Sections 5.1 through 5.3 below. The last two steps are
discussed in Sections 6.1 and 6.2.

In taking the steps described in Chapter 5 or 6, the POTW authority may want to consider
employing a consultant when evaluating the potential for a radioactive contamination problem.
Part of the POTW's consideration will depend upon available resources and experience of the
authority's own personnel, as well as the initial findings regarding the number and complexity of
the sources of radioactive material in the service area. Assistance and advice are available to the
POTW authority from the appropriate State Radiation Control Program, the Conference of
Radiation Control Program Directors, the NRC Regional Office, and the EPA Regional
Radiation Program.  Information regarding these programs and offices, including contact
information, is provided in Appendices B, C, D, and E.

5.1   DETERMINE WHAT RADIOACTIVE  MATERIALS  MAY BE
      DISCHARGED INTO OR  OTHERWISE  ENTER THE
      WASTEWATER COLLECTION AND TREATMENT SYSTEM

The POTW operator should identify the source(s) of radioactive materials that enter the
wastewater system.  As described in Chapter 3, the sources of potential contamination may be
from naturally occurring and/or man-made materials. The ISCORS survey indicated that the
most common sources are likely to be naturally occurring and medical radionuclides
(ISCORS 2003).  Appendix L contains an analysis of the results of the ISCORS survey, which
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may provide valuable perspective on which types of radioactive material are possible sources in
any POTW.

To determine if information is available regarding the potential presence of NORM and
TENORM in the service area, the POTW operator should contact the State Radiation Control
Agency (see Appendix E).  EPA regional radiation program managers (see Appendix D) may
also be able to assist in this question.

To determine potential sources of man-made radioactive materials, the POTW operator should
identify facilities in the  service area that are licensed to use radioactive materials.  A list of
licensees, obtained from the appropriate regulatory agency, should be used to determine likely
sources. If the POTW is in an Agreement State, the State can provide a list of the licensees and
the material(s) they are licensed to use. If the POTW is not in an Agreement State, the POTW
can check with the NRC (e.g., the NRC Regional Office) to identify the licensees that are located
in their service area. If the POTW services any Federal government facilities, it will also be
necessary to contact the NRC Regional Office, even in an Agreement State.  These facilities
cannot be licensed by the State and are always under NRC purview.  For example, Army, Navy,
and Air Force facilities are licensed by the NRC.5 In all States, the POTW should contact the
State radiation control program office  for information regarding non-AEA man-made radioactive
materials (i.e., accelerator produced material, NARM). If there is  a DOE facility in the service
area, the POTW should  contact the DOE facility directly to determine if there may be a potential
for the discharge of radioactive materials to the sanitary sewer.

Information on what radioactive  material is authorized for use is as important as identifying the
user. For instance, if a wastewater discharger only uses a "sealed source", it is unlikely the
facility would discharge radioactive material in the sewer system.  In the case of licensed
materials, this information can be requested from the licensee or from the NRC or Agreement
State; for NORM and TENORM, the facility would need to be contacted directly. After the
likely sources of radioactive materials have been identified, the facility should be contacted to
determine if any  continuous or accidental releases may have occurred.

5.2   DETERMINE IF MONITORING  OR SAMPLING FOR  RADIOACTIVE
       MATERIAL AT THE POTW SHOULD BE PERFORMED

In Section 5.1 above, a number of suggested steps were provided for a POTW to follow in
learning what available  information may exist on radioactive materials entering into or being
discharged into the sanitary sewer system.  Following are some criteria that may be useful in
determining if it is appropriate to sample test the POTW facility for radon, or to sample the
sewage sludge or ash for radionuclide  content:
   Additional information for Navy and Air Force facilities may be obtained from the corresponding Service
   Coordinating Committee. The Navy Committee can be contacted directly at 703/602-2582 and the Air Force
   Committee can be contacted directly at 210/536-3331.


ISCORS Technical Report 2004-04               5-2                           Final, February 2005

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The POTW facility is located in an area with elevated levels of uranium and radium occurrence
in soils, bedrock or ground water (see Figure 3.1, Figure 3.3, or Figure 3.4). Naturally occurring
radioactive materials may enter the POTW with wastewater discharges, air or water infiltration,
or stormwater runoff into the collection system. Most importantly, check with your State
Drinking Water or Radiation Control Program to determine if NORM is present in the ground
water.

There are drinking water treatment plants that may discharge residuals into the sewer system
from treatment of source water to comply with EPA drinking water MCLs for radium and
uranium, or for alpha and beta emitting radionuclides. The current standards are: combined
radium-226/228, 5 pCi/L; total uranium, 30 |J,g/L; a combined standard of 4 mrem/yr for beta
emitters; and a gross alpha standard of 15 pCi/L, not including radon and uranium (see
40 CFR Part 141).

There are industrial facilities in the POTW service area for the following industries which
discharge significant quantities of untreated process wastewater into the sewer system: ceramics,
electronics, minerals or metal fabrication (any one of aluminum, copper, gold, silver, phosphate,
potassium, vanadium, zinc, zirconium, tin, rare earths, molybdenum, titanium, depleted uranium,
radium), paper and pulp, metal foundry and engine manufacture, munitions and armament
manufacturing; luminous watch and clock manufacture, cement or concrete, optics, electric
lighting, gypsum board manufacture, welding, paint and pigment, or fertilizer manufacture.
What percentage of total discharge to the system is provided by these facilities? All of these
industries have been associated with the use of TENORM materials or production of TENORM
wastes.

There are NRC or Agreement State licensees or DOE or DoD facilities in the  service area that
discharge to the sewer system in the following categories:  medical, medical laboratory, research
and development, college or university, nuclear laundries, decommissioning facilities for
byproduct material facilities, UFe production plants, hot cell operations, uranium enrichment
plants, or uranium fuel fabrication plants.  There are State licensed accelerators that may
discharge to the sewer system.  There are facilities which discharge landfill leachate or
Superfund site discharges in the service area.  It is important to know how many such licensees
and other sources there are and how much they discharge to the system annually. What
percentage of total discharges of radioactive material to the system is provided by these
facilities?

While there have been few studies conducted to evaluate the volumes and movement of
radionuclides throughout the sewage system and their accumulation and occurrence in sewage
sludge or ash, a POTW can make some qualitative judgments about whether monitoring or
surveying is prudent based on an informed analysis of dischargers to the system.

•  If there are no occurrences of any of the possible sources listed above in the system, the
   likelihood of finding contamination by radioactive materials in the sewage sludge and ash is
   low, but is still remotely possible.  Sampling or monitoring would not likely be warranted.

•  If either criterion 1 or 2 applies, the possibility does exist that NORM or TENORM could be
   elevated, and the sewage sludge or ash and indoor radon may merit sampling. If there are
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   poorly ventilated indoor areas of the POTW where sewage sludge or ash materials are stored,
   or where radon gas can infiltrate, there may be a concern for accumulation of radon and
   exposure to workers.  Therefore, testing of the air for radon may be appropriate.

•  If industries listed in criterion 3 are present in the  service area, the possibility exists that
   NORM or TENORM could occur in the sewage sludge and ash, and warrant radionuclide
   sampling of the POTW sludge and ash, and monitoring of the air in poorly ventilated indoor
   areas of the POTW for radon.

•  If criterion 4 applies, (i.e., there are either multiple licensees in the service area, or the
   licensees and other sources contribute a significant fraction—more than a few percent—of
   the wastewater in the sewer system), it may be appropriate to periodically sample and test the
   sewage sludge and ash for the presence of radionuclides, particularly those that are man-
   made.  Since the volume of wastewater discharged from a licensee may or may not be
   indicative of the amount of radionuclides discharged during the year, it may also be
   appropriate to review licensee discharge records as a better indicator of the type and quantity
   of radioactive materials that enter the system.

•  If any of criteria 1, 2, or 3 applies and criterion 4 also applies, the likelihood exists for the
   occurrence of NORM, TENORM, and man-made radionuclides in the sewage sludge or ash,
   and it may be appropriate to sample the sewage sludge or ash,  or to monitor indoor air for
   radon. (It should be noted that there may be other sources causing  the accumulation of radon
   gas in the POTW, other than the sewage sludge and ash.)

Further information on identifying and dealing with new industrial sources, radioactive
contaminants, and individual facilities is provided in a guidance document developed by the
National Biosolids Partnership (NBP  1999).

The results of the ISCORS survey and associated dose modeling (see Section 4.4) may be helpful
to POTWs when deciding whether they should sample.

5.3    HOW CAN A  POTW OPERATOR SAMPLE AND ANALYZE
       SEWAGE SLUDGE AND ASH OR  MONITOR FOR RADON?

If it is found that sampling of sewage sludge and ash should be conducted (either because of
detected contamination or undetected radioactive materials are believed to be present), a
carefully planned program should be executed. An initial gamma  scan and gross alpha and gross
beta determination may be useful as an inexpensive screening tool for further analysis. A
gamma spectrometer is used to estimate gamma-emitting radionuclide  concentrations. Gamma
spectrometry can discriminate among various radionuclides on the basis of characteristic gamma
and X-ray energies to provide a nuclide-specific measurement. Gross alpha or gross beta activity
analyses are used to screen samples to determine the need for nuclide-specific analyses. Further
assessments may require analyses for specific radioactive materials. It should be noted that the
ISCORS survey consisted of a single  sample taken at  each of the participating POTWs. If a
POTW operator determines that sludge sampling is warranted, based on the criteria in
Section 5.2, it may be prudent to  obtain analyses on more than one sample, to reduce the
likelihood of unrepresentative results.
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If the POTW operator determines that either NORM/TENORM or other AEA radioactive
material could be present in the sewage sludge or ash, various analyses could be considered to
confirm the presence or absence of these materials. Where NORM/TENORM is suspected, a
gross alpha and beta screen can be performed.  If gross alpha and/or gross beta results are 5
pCi/g or greater, radiochemical analyses should be performed for radium-226 and radium-228.
Gamma spectroscopy should also be performed to determine the presence of other nuclides,
including the daughter nuclides of radium-226 and radium-228. It should be noted that the
gamma spectroscopy results for radium-226 will differ from the radiochemical results. The
radiochemical  results are more accurate for radium-226 and radium-228 and should be used to
determine dose as explained in Chapter 6.  If AEA material is suspected,  gamma spectroscopy
should be performed to identify the presence of specific gamma-emitting radionuclides.  All
analyses should be performed on a dry weight basis.  In addition, in order to account for  isotopes
that do not have significant gamma contributions, samples should be held for 21 days or  more to
allow ingrowth of the short-lived gamma-emitting progeny. Because thorium is likely not in
equilibrium with its progeny because of differences in solubility between the different elements,
alpha spectroscopy is more appropriate if a discharge is suspected.

Most States have radon offices and their personnel may be able to provide some assistance as to
previous measurements in the county where POTWs are located,  means and methods for
conducting radon surveys at the POTW or at land application sites, and lists of licensed or
certified radon contractors who could conduct surveys.  Private radon proficiency programs can
also provide lists of certified radon professionals working in the area. Information on these
professionals can be found at: http://www.epa.gov/radon/iaq/proficiency.html.

The quickest way to test for radon is with short-term tests. Short-term tests take place at a site
for 2 days-90 days, depending on the device or devices utilized.  Some detectors that could be
used include "charcoal canisters," "alpha track," "electret ion chamber," "continuous monitors,"
and "charcoal liquid scintillation detectors." Because radon levels tend to vary from day to day
and season to season, a short-term test  is less likely than a long-term test to yield the year-round
average radon  level.  If results are needed quickly, however, an initial short-term test followed by
a second short-term test can be used  to decide whether levels of radon at the POTW require
remediation. Long-term tests remain at a site for more than 90 days. "Alpha track" and
"electret" detectors are commonly used for this type of testing. A long-term test provides a
reading that is  more likely to yield the year-round average radon level than a short-term test.

The EPA guidance, POTW Sludge Sampling and Analysis Guidance Document (1989), provides
information on conducting sampling and analysis of sludge.6  Additional  information on
collecting sewage sludge and ash samples can be found in the Quality Assurance Program Plan
used in the ISCORS Survey (ISCORS 2003). Information on how to collect samples, what
containers to put them in, how to preserve them, and other sampling steps, should be worked out
in consultation with the selected analysis vendor. Also, some analyses require specific time
       The EPA guidance document can be obtained from the Education Resource Information Center
       (ERIC number W134) by calling (800) 276-0462 or the National Technical Information Center
       (NTIS number PB93-227957) at (800) 553-NTIS.
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periods for counting radionuclide decay emissions or collecting radon or other decay products.
These time periods may vary with the radionuclides being tested and can take several days or
weeks to complete.

A radiochemical laboratory should be selected before sampling so that the laboratory may be
consulted on the analytical methodology and sampling protocol. A list is maintained by the
Conference of Radiation Control Program Directors (CRCPD) of laboratories that provide
radiological analysis of diverse materials, have quality assurance and quality control programs,
and will perform work for government and private firms. Appendix J lists those laboratories
from the December 2002 CRCPD list that have indicated they perform analyses of sludge
samples, and provides some direction on evaluating radiochemical laboratories.  Individual
States may have specific requirements for laboratory certification.
 Box 5.1       Typical Analysis Costs
 Costs for analysis will depend on the type of analyses that are requested. The more detailed or
 complicated the analysis, the more expensive and time demanding the analysis becomes.
 Gamma spectroscopy analysis for one sample could cost a few hundred dollars, gross
 alpha/beta analysis may cost a few hundred dollars and costs for radiochemical analysis for
 alpha and beta emitters may range from several hundred to over one thousand dollars,
 depending on the radionuclides analyzed.  For evaluations of radon, simple short-term
 measurements of radon in air can be relatively inexpensive and easy to collect.
A POTW operator who elects to conduct a laboratory radionuclide analysis of a facility's sewage
sludge and ash can use the information to determine whether any further sampling is needed, or
whether an unacceptable exposure condition may exist that could be addressed by changes in
management practices. Data on specific radionuclide levels can be evaluated by using the
screening calculations provided in Chapter 6. These screening calculations allow a rough
estimation of possible radiation dose.  However, it is very important to contact a radiation
protection specialist for assistance in evaluating the results of preliminary sampling and analysis
and the screening calculations before conducting a more extensive sampling or monitoring
program, or before changing existing management practices.

If there is any concern by the POTW operator regarding potential radiological contamination of
buildings or facilities where sewage sludge or ash is land applied or disposed in a landfill, there
may be a need to conduct an appropriate radiological survey, as discussed in Section 6.2.
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6   HOW CAN A  POTW OPERATOR INTERPRET LEVELS OF
    RADIOACTIVITY DETECTED  IN THE PLANT?

Once data is collected on levels of radioactive materials in the sewage sludge or ash, in the
indoor air of the POTW, or in soils or other areas where sludge had been previously managed, it
is necessary to evaluate the quantitative results to determine whether they are at a level of
concern, and whether any follow-up action is needed to assure protection of workers and the
general public. This evaluation can be performed in various ways, depending on the type of
sampling or monitoring  data obtained and the levels of specific radionuclides. The following
sections provide instruction on performing simple screening calculations, based on the dose
modeling results reported by ISCORS. Performing these calculations provides important
perspective on the need for any further actions, including routine monitoring or changes to
current sludge management practices.

Conservatively calculated reference unit dose concentrations for specific radionuclides are
provided in Table 6.2 for assessing potential exposure to workers at the POTW, and in Table 6.5
for assessing potential exposures at a land application site.  In addition  to assessing potential
radiation dose, the values in these tables can be used to determine whether any further actions are
warranted.  Based on the ISCORS analysis of typical sludge management practices
(ISCORS 2003b), if the  concentration of individual radionuclides in sewage sludge or ash is less
than or equal to the concentrations in these tables, there is reasonable confidence that potential
doses are insignificant (i.e., below 1 mrem/year). However, it must be  noted that the values in
these tables were developed for the purpose of providing a screening tool, and should not be used
to evaluate actual exposures or to estimate actual doses without additional site-specific analyses.
The recommended screening process is contained in Sections 6.1.2  and 6.1.3. The screening
table concentrations are  based on an effective dose equivalent of 1 mrem/year per  source or
practice, which is the Negligible Individual Dose determined by the National Council on
Radiation Protection and Measurements (NCRP 1993) and is consistent with the consensus
standard from the American National Standards Institute/Health Physics Society
(ANSI N13.12-1999) for control of solid materials.

ISCORS believes that if the annual dose from all radionuclides detected in a sewage sludge or
ash sample, estimated through procedures provided in this Chapter, is 10 mrem or less, no further
steps are warranted.  Where the estimated annual dose from all radionuclides exceeds 10 mrem,
ISCORS recommends that the POTW operator consult with the State radiation protection
regulatory agency (see Appendix E). This conservative estimated dose (i.e., 10 mrem/year)
should not be  considered a radiation exposure limit. Instead, it is provided solely as a
recommendation for when the POTW operator should seek further consultation. It is not to be
interpreted as  a requirement for taking other actions. The 10 mrem/year criterion is not a limit,
does not include radon, and is not intended to suggest that higher dose levels are unacceptable.
In general, ISCORS believes that the screening process described in this section will identify and
address any potential radiological exposures associated with sewage sludge or ash management
practices, and will provide a guideline for determining whether further  actions are needed to
ensure public  and worker health and safety.
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The basis for the values used in the screening tables presented in this chapter is the ISCORS
Dose Modeling Assessment (ISCORS 2003b).  Conservatism is built into these values by use of
the 95th percentile dose-to-source ratios. Therefore, estimates of annual doses based on these
Screening tables are more likely to overestimate actual exposures than to underestimate them.
Nevertheless, because it is possible that the dose could be greater, ISCORS recommends that a
POTW operator should consult with the appropriate State authorities if estimated annual doses
exceed 10 mrem.

6.1   ESTIMATE POTENTIAL DOSES FROM RADIOACTIVE MATERIAL
      IN SEWAGE SLUDGE AND ASH THROUGH SCREENING
      CALCULATIONS

This section describes how to estimate potential doses from radioactive material in sewage
sludge and ash, where some preliminary sampling data are available, using several simple
screening calculations.  These calculations are based on the exposure scenarios described in the
ISCORS Dose Modeling Report (ISCORS, 2003b), and were used in developing the dose
estimates in Chapter 3 (Table 3.6). The screening calculations are divided into two parts:
estimates of radiation exposure (primarily to workers in the POTW) from POTW operations
(Section 6.1.1) and estimates of radiation exposure (primarily to the public) from the use or
disposal of sewage sludge or ash outside the POTW (Section 6.1.2).  In each case, doses are
calculated for all significant radionuclides detected in the sludge, excluding the radon pathway.
Radon concentrations are calculated separately. Examples of these screening calculations are
provided in Appendix K.

The estimated doses derived from  use of these screening calculations are considered to be very
conservative. Doses at a specific POTW should be evaluated by using realistic, site-specific
values and parameters.

6.1.1     Compare Estimated Doses to Existing Standards

Standards and guidance for radiation protection of the public, of workers, and of the
environment, developed by regulatory agencies and national and international organizations, are
listed in Table 6.1 as background information.  These standards, however, are generally not
directly applicable to situations involving sewage sludge or ash management. The relevance of
any of these standards and guidance depends on a number of factors, including the laws and
regulations that directly apply to the POTW. Determining which standards or guidance should
be used to compare to doses from  screening calculations requires consultation with appropriate
State or Federal regulatory agencies (see Appendices C, D, and E). The specific authority of
each regulatory agency is discussed in Chapter 4.
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 Table 6.1     What are the Existing Standards for Protection of Human Health
              from Exposure to Hazards Such as Ionizing Radiation and
              Radioactivity?
Standard or Guideline (Year)
Indoor Air Radon in Homes and Schools
(A Citizen 's Guide to Radon (2004 and
2002), and Radon Measurements in
Schools-Revised Edition (2002))
Radiation Protection Guidance to Federal
Agencies for Occupational Exposure
(1987) 1
Occupational Radiation Protection
(1987) (Workers not covered by other
regulations) :
Occupational Radiation Protection
(1993) (DOE workers)1
Occupational Dose Limits for Adults
(1991) (Applies to NRC and Agreement
State Licencees) :
Drinking Water Maximum Contaminant
Levels (MCLs)
(1976 and 2000)
Nuclear Regulatory Commission Public
exposure limit, from single licensed
operation (1991)
Radiation Protection of the Public and
the Environment (1990)
Radioactive Waste Management (1993)
NRC Radiological Criteria for License
Termination (Decommissioning) for
Unrestricted Use (1997)
State Decommissioning Criteria
National Emission Standards for
Hazardous Air Pollutants; Radionuclides
Type
EPA guidance
Final guidance
Regulation
(29 CFR 9 10. 1096)
Regulation (10 CFR
Part 835)
Regulation (10 CFR
Part 20. 1201)
Regulation
(40 CFR 141)
Regulation
(10 CFR 20.1301)
DOE Order
(DOE 5400.5)
DOE Order
(DOE 435.1)
Regulation
(10 CFR 20. 1402)
Various regulations or
guidance
Regulation (40 CFR 61
Subparts H and I)
Limit
4 pCi/L or
0.02 Working Levels
As low as reasonably achievable
(ALARA) and not to exceed 5 rem in
any year by an adult radiation worker.
Also includes guidance to not exceed
0.5 rem to an unborn worker's child or
not exceed one-tenth of the adult value
for individuals under eighteen years old
5 rem/yr whole body dose
5 rem/yr total effective dose equivalent
5 rem/yr total effective dose equivalent
Gross Alpha - 15 pCi/L
Beta/photon emitters - 4 mrem/yr
Radium (226 & 228) - 5 pCi/L
Tritium - 20,000 pCi/L
Strontium-90 - 8 pCi/L
Uranium - 30 ug/liter
100 mrem/year
100 mrem/year total effective dose
equivalent
25 mrem/year - All pathways, except air
10 mrem/year - Air pathway
25 mrem/year and ALARA
Background - 100 mrem/year
10 mrem/year
1 Occupational Exposure refers to radiation workers. Radiation workers are personnel that have been
trained in radiation protection practices and are monitored for exposure to radiation. POTW workers
are not radiation workers and these standards do not apply to them.
ISCORS Technical Report 2004-04
6-3
Final, February 2005

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6.1.2    Estimating POTW Worker Radiation Dose

The steps for estimating radiation dose for POTW workers, considering the case where POTW
workers are exposed to a large quantity of sewage sludge in a confined area, such as in a storage
or loading room are provided below.  If radon monitoring has not been performed, but data are
available on levels of Ra-226 and Th-228 in the sewage sludge or ash, then use Step 3 of
Screening  Calculation A (Box 6.1, also see Appendix K) can be used to provide conservative
estimates of radon concentrations.  These conservative estimated doses were developed for
screening purposes only. Estimates of potential doses for specific POTWs would require
modeling of individual site-specific characteristics.
 Box 6.1       Screening Calculation A: POTW Workers
 Purpose: To estimate doses and radon concentrations for POTW Workers in a loading or
 storage room.

 Calculation Procedure:

 1.   Select Radionuclides for which the sludge sample concentration is greater than the
     "POTW Screening Concentration" in column 3 of Table 6.2.
 2.   Multiply the sample concentrations for the selected radionuclides by the dose-to-source
     ratios (DSRs) in column 2 of Table 6.2, and add them together to get the total dose from
     non-radon pathways.
 3.   In cases where radon measurements have not been taken, the sample concentrations for
     Ra-226 and Th-228 can be multiplied by the radon conversion factors in Table 6.3 to
     obtain the radon concentrations in Working levels or pCi/liter. The values in Table 6.3
     should be used if no specific information is available regarding the air exchange rate and
     room height for the loading or storage room. If specific information on air exchange rate
     and room height is available, the values from Table 6.4 may be used. The calculated
     concentrations can then be compared with EPA guidelines described in Section 6.1.4.
 Notes:

 •   The sample concentration of Th-227 is a surrogate for Ac-227.

 •   Screening calculation assumes a worker spends most of his/her time in a room that
     contains a large quantity of sludge, either for storage or for loading.

 •   Screening calculation for radon makes conservative assumptions about room size,
     ventilation, etc.  An alternative calculation, presented in Appendix K, can be used to make
     adjustments for site-specific room characteristics.

 •   If radon concentrations (above 4.0 pCi/L or 0.02 WL) are calculated, consult Section 6.1.4
     for EPA recommendations on radon monitoring.
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 Table 6.2    Reference Values for Screening Calculation for Non-Radon
              Pathways for Screening Calculation A
Radionuclide
Ac-227
Am-241
Be-7
C-14
Ce-141
Co-57
Co-60
Cr-51
Cs-134
Cs-137
Eu-154
Fe-59
H-3
1-125
1-131
In-111
K-40
La-138
Np-237
Pa-231
Pb-210
Po-210
Pu-238
Pu-239
Ra-226
Ra-228
Sm-153
Sr-89
Sr-90
Th-228
Th-230
Th-232
Tl-201
Tl-202
U-233
U-234
U-235
U-238
Zn-65
POTW Loading DSR
(mrem/y per pCi/g)
4.05E-01
2.35E-02
1.23E-02
5.60E-07
1.25E-02
1.92E-02
7.00E-01
7.40E-03
4.07E-01
1.46E-01
3.32E-01
3.31E-01
1.33E-03
6.00E-04
9.20E-02
8.05E-02
4.53E-02
3.46E-01
2.89E-02
8.05E-02
1.33E-03
4.35E-04
1.80E-02
2.38E-02
4.84E-01
2.59E-01
5.80E-03
3.95E-04
1.05E-03
4.55E-01
1.68E-02
8.35E-02
1.01E-02
1.05E-01
7.55E-03
6.15E-03
3.68E-02
1.13E-02
1.60E-01
POTW Screening
Concentration(pCi/g)
2.5
43
82
1.8E+06
80
52.
1.4
140
2.5
6.8
3.0
3.0
750
1700
11
12
22.
2.9
35
12
750
2300
56
42
2.1
3.9
170
2500
960
2.2
60
12
99
9.5
130
160
27
88
6.2
ISCORS Technical Report 2004-04
6-5
Final, February 2005

-------
 Table 6.3    Indoor Radon Working Levels and pCi/Liter Concentration per Unit
              Sludge Concentration for Screening Calculation A
Radionuclide (Daughter)
Ra-226 (Rn-222)
Th-228 (Rn-220)
POTW Loading
WL
5.0E-04
2.0E-02
pCi/L
3.2E-01
1.1E+01
NOTE:
Default values to be used if information is not available on the room height and air exchange rate.
 Table 6.4    Indoor Radon Working levels and pCi/Liter Concentration per Unit
              (pCi/g) Sludge Concentration for Screening Calculation A
Air exchange
rate (per hour)
1.5
3
5
Room height
(m)
2
4
6
2
4
6
2
4
6
Ra-226
WL
5.0E-4
2.5E-4
1.7E-4
1.6E-4
8.2E-5
5.5E-5
6.9E-5
3.5E-5
2.3E-5
pCi/L
0.32
0.15
0.097
0.14
0.069
0.045
0.082
0.041
0.026
Th-228
WL
2.0E-2
l.OE-2
6.8E-3
l.OE-2
5.0E-3
3.3E-3
5.9E-3
2.9E-3
1.9E-3
pCi/L
11
4.7
2.9
9.0
4.1
2.6
8.0
3.8
2.5
NOTE:
This table may be used when information is available to describe the air exchange rate and the room height for
the loading or storage room. The combination of air exchange rate and room height should be matched as well as
can be. If the match is not exact, match to values of air exchange and room height that are smaller than the actual
values.
6.1.3    Estimating Radiation Dose Due to Use or Disposal of Sewage
         Sludge and Ash

The calculations for radiation dose from use or disposal of sewage sludge and ash are presented
in a two-tiered format.  Screening Calculation B (Box 6.1, also see Appendix K) is an
upper-bound estimate.  If Screening Calculation B is not appropriate, then Screening
Calculation C (Box 6.3, also see Appendix K), which provides a scenario-specific evaluation,
should be used. These conservative estimated doses were developed for screening purposes
only. Estimates of potential doses for specific POTWs would require modeling of individual
site-specific characteristics.
ISCORS Technical Report 2004-04
6-6
Final, February 2005

-------
 Box 6.2       Screening Calculation B: Non-POTW Upper-Bound
 Purpose: To obtain an upper bound on the reasonably likely radiation doses that may be
 experienced by individuals outside the POTW.

 Calculation Procedure:

 1.   Select the radionuclides for which the sludge sample concentration is greater than the
     "Screening concentration" in column 3 of Table 6.5.
 2.   Multiply the sample concentrations for the selected radionuclides by the DSRs in
     column 2 of Table 6.5, and add them together to get the total dose from non-radon
     pathways.
 3.   Divide the Ra-226 sample concentration in pCi/g by 57 to obtain the pCi/liter indoor
     Rn-222 concentration, or by 8,300 to obtain the indoor Working Levels.
 Notes:

 •   The sample concentration of Th-227 is a surrogate for Ac-227.

 •   If radon concentrations above 4 pCi/L or 0.02 WL are calculated, consult Section 6.1.4 for
     EPA recommendations on radon monitoring.
 •   Screening calculation assumes that land application occurs for a maximum of 20 years.  If
     additional years of land  application are anticipated, use Screening Calculation C (Box 6.3).
 •   If doses from ash are to  be evaluated, then Screening Calculation C (Box 6.3) should be
     used.
ISCORS Technical Report 2004-04                6-7                           Final, February 2005

-------
 Table 6.5     Reference Values for Screening Calculations B and C
Radionuclide
Ac-227
Am-241
Be-7
C-14
Ce-141
Co-57
Co-60
Cr-51
Cs-134
Cs-137
Eu-154
Fe-59
H-3
1-125
1-131
In-111
K-40
La-138
Pb-210
Pu-238
Pu-239
Ra-226 *
Ra-228
Sm-153
Sr-89
Sr-90
Th-228
Th-230
Th-232
Tl-201
Tl-202
U-234
U-235
U-238
Zn-65
Max DSR (land application 20 yr)
(mrem/y per pCi/g)
1.18E+01
7.99E-01
4.04E-05
4.84E-01
2.60E-05
6.60E-04
2.59E-01
1.27E-05
6.52E-02
2.08E-01
1.80E-01
8.81E-04
1.55E-04
6.99E-02
1.31E-02
2.73E-05
2.84E-02
6.57E-02
2.93E-01
7.04E-01
7.74E-01
9.82E-01
4.12E-01
1.78E-06
4.70E-05
3.59E-01
5.23E-01
1.25E+00
2.97E+00
3.28E-06
8.03E-05
2.37E-01
2.22E-01
2.12E-01
1.13E-02
Screening Concentration
(PCi/g)
0.08
1.25
2.48E+04
2.07
3.85E+04
1.51E+03
3.86
7.87E+04
15.3
4.81
5.56
1.14E+03
6.46E+03
14.3
76.3
3.66E+04
35.2
15.2
3.41
1.42
1.29
1.02
2.43
5.62E+05
2.13E+04
2.79
1.91
0.80
0.34
3.05E+05
1.25E+04
4.22
4.50
4.72
88.3
* Ra-226 DSR excludes the radon pathway.
ISCORS Technical Report 2004-04
Final, February 2005

-------
 Box 6.3       Screening Calculation C: Non-POTW Scenarios
 Purpose:  To estimate radiation doses under different exposure scenarios outside the POTW.
 Calculation Procedure:
 1.   Select the radionuclides for which the sludge sample concentration is greater than the
     "Screening Concentration" in column 3 of Table 6.5.
 2.   Select the exposure scenarios that are to be evaluated. The scenarios, organized by sludge
     management practices, are:
        Agricultural Application B
        Note: consideration should be given to both the number of past applications as well as
        potential future applications.
              Onsite Resident (Table 6.6)
              Nearby Town (Table 6.6)
              Sludge Application Worker (Table 6.7)
        Land Application for Reclamation
              Recreational User (Table 6.8)
        Landfill
              Municipal Solid Waste Landfill Neighbor (Table 6.8)
              Impoundment Neighbor (Table 6.8)
        Incineration
              Incinerator Neighbor (Table 6.8)
 3.   For each scenario selected, multiply the sample concentrations for the selected
     radionuclides by the DSRs from the appropriate table, and add them together to get the
     total dose from non-radon pathways.
 4.   If appropriate, multiply the sample concentrations by the radon conversion factors in
     Table 6.9 or 6.10 to obtain the radon concentrations in working levels (WL) or pCi/liter,
     respectively.
 Notes:
 Step 1 is optional.  The alternative is to select all the radionuclides for which there are both
 sample measurements and calculated DSRs.
 The sample concentration of Th-227 is a surrogate for Ac-227.
ISCORS Technical Report 2004-04                6-9                           Final, February 2005

-------
Table 6.6    Agricultural Application Non-Radon DSR (mrem/y per pCi/g) Values
             for Screening Calculation C
Radio-
nuclide
Ac-227
Am-241
Be-7
C-14
Ce-141
Co-57
Co-60
Cr-51
Cs-134
Cs-137
Eu-154
Fe-59
H-3
1-125
1-131
In-Ill
K-40
La-138
Pb-210
Pu-238
Pu-239
Ra-226
Ra-228
Sm-153
Sr-89
Sr-90
Th-228
Th-230
Th-232
Tl-201
Tl-202
U-234
U-235
U-238
Zn-65
Onsite Resident (years of application)
1
1.03E-02
1.43E-03
1.40E-06
2.42E-02
4.91E-08
4.03E-04
3.54E-02
5.58E-09
1.88E-02
1.31E-02
1.74E-02
1.16E-05
1.20E-05
7.06E-06
4.81E-18
O.OOE+00
1.88E-03
1.41E-02
1.91E-02
1.22E-03
1.35E-03
4.91E-02
3.55E-02
O.OOE+00
2.64E-06
3.04E-02
1.49E-02
6.25E-02
5.28E-02
O.OOE+00
3.45E-13
1.01E-03
2.50E-03
9.90E-04
7.33E-03
5
4.80E-02
7.09E-03
1.41E-06
1.21E-01
4.91E-08
6.54E-04
1.37E-01
5.58E-09
5.31E-02
6.25E-02
7.44E-02
1.16E-05
5.41E-05
7.13E-06
4.81E-18
O.OOE+00
6.38E-03
4.61E-02
9.23E-02
5.98E-03
6.72E-03
2.46E-01
1.71E-01
O.OOE+00
2.66E-06
1.35E-01
4.11E-02
3.13E-01
2.64E-01
O.OOE+00
3.45E-13
4.96E-03
1.23E-02
4.86E-03
1.13E-02
20
1.53E-01
2.79E-02
1.41E-06
4.84E-01
4.91E-08
6.60E-04
2.59E-01
5.58E-09
6.52E-02
2.08E-01
1.80E-01
1.16E-05
1.55E-04
7.13E-06
4.81E-18
O.OOE+00
9.51E-03
6.57E-02
2.98E-01
2.24E-02
2.66E-02
9.82E-01
4.12E-01
O.OOE+00
2.66E-06
3.59E-01
4.90E-02
1.26E+00
1.06E+00
O.OOE+00
3.45E-13
1.85E-02
4.58E-02
1.81E-02
1.13E-02
50
2.53E-01
6.72E-02
1.41E-06
1.21E+00
4.91E-08
6.60E-04
2.77E-01
5.58E-09
6.52E-02
3.74E-01
2.20E-01
1.16E-05
1.69E-04
7.13E-06
4.81E-18
O.OOE+00
9.65E-03
6.64E-02
5.06E-01
4.91E-02
6.53E-02
2.45E+00
4.62E-01
O.OOE+00
2.66E-06
4.81E-01
4.90E-02
3.16E+00
2.63E+00
O.OOE+00
3.45E-13
4.03E-02
9.99E-02
3.94E-02
1.13E-02
100
3.02E-01
1.27E-01
1.41E-06
2.41E+00
4.91E-08
6.60E-04
2.77E-01
5.58E-09
6.52E-02
4.77E-01
2.26E-01
1.16E-05
1.69E-04
7.13E-06
4.81E-18
O.OOE+00
9.65E-03
6.64E-02
6.09E-01
8.01E-02
1.26E-01
4.83E+00
4.62E-01
O.OOE+00
2.66E-06
5.04E-01
4.90E-02
6.44E+00
5.25E+00
O.OOE+00
3.45E-13
6.55E-02
1.62E-01
6.35E-02
1.13E-02
Nearby Town (years of application)
1
5.94E-05
4.22E-06
6.43E-12
5.22E-07
7.12E-11
2.98E-10
1.36E-08
1.80E-11
2.84E-08
4.28E-08
7.50E-09
7.44E-10
5.32E-07
1.55E-08
2.12E-08
4.54E-11
4.94E-10
2.69E-08
4.04E-07
3.62E-06
3.95E-06
1.19E-04
1.96E-04
7.39E-11
5.70E-10
5.76E-08
3.41E-04
4.30E-05
3.51E-04
4.49E-11
2.19E-10
1.15E-06
1.19E-06
1.04E-06
5.64E-09
5
2.78E-04
2.10E-05
8.73E-12
5.22E-07
7.19E-11
8.18E-10
6.68E-08
1.86E-11
1.04E-07
2.14E-07
3.72E-08
7.97E-10
5.32E-07
1.62E-08
2.13E-08
4.55E-11
2.40E-09
1.06E-07
1.95E-06
1.78E-05
1.97E-05
5.94E-04
9.44E-04
7.39E-11
5.87E-10
2.87E-07
9.40E-04
2.15E-04
1.75E-03
4.49E-11
2.22E-10
5.64E-06
5.84E-06
5.10E-06
1.37E-08
20
8.84E-04
8.25E-05
8.73E-12
5.22E-07
7.19E-11
8.45E-10
2.08E-07
1.86E-11
1.49E-07
8.46E-07
1.35E-07
7.97E-10
5.32E-07
1.62E-08
2.13E-08
4.55E-11
7.32E-09
2.21E-07
6.41E-06
6.65E-05
7.80E-05
2.36E-03
2.46E-03
7.39E-11
5.87E-10
1.10E-06
1.12E-03
8.56E-04
7.02E-03
4.49E-11
2.22E-10
2.10E-05
2.19E-05
1.90E-05
1.40E-08
50
1.49E-03
1.99E-04
8.73E-12
5.22E-07
7.19E-11
8.45E-10
2.62E-07
1.86E-11
1.49E-07
1.99E-06
2.27E-07
7.97E-10
5.32E-07
1.62E-08
2.13E-08
4.55E-11
9.30E-09
2.45E-07
1.11E-05
1.46E-04
1.91E-04
5.85E-03
2.80E-03
7.39E-11
5.87E-10
2.16E-06
1.12E-03
2.12E-03
1.75E-02
4.49E-11
2.22E-10
4.58E-05
4.83E-05
4.14E-05
1.40E-08
100
1.78E-03
3.75E-04
8.73E-12
5.22E-07
7.19E-11
8.45E-10
2.64E-07
1.86E-11
1.49E-07
3.27E-06
2.46E-07
7.97E-10
5.32E-07
1.62E-08
2.13E-08
4.55E-11
9.41E-09
2.46E-07
1.37E-05
2.39E-04
3.71E-04
1.15E-02
2.81E-03
7.39E-11
5.87E-10
2.64E-06
1.12E-03
4.19E-03
3.49E-02
4.49E-11
2.22E-10
7.42E-05
8.05E-05
6.69E-05
1.40E-08
ISCORS Technical Report 2004-04
6-10
Final, February 2005

-------
Table 6.7    Sludge Application Worker Non-Radon DSR Values
             (mrem/y per pCi/g) for Screening Calculation C
Radionuclide
Ac-227
Am-241
Be-7
C-14
Ce-141
Co-57
Co-60
Cr-51
Cs-134
Cs-137
Eu-154
Fe-59
H-3
1-125
1-131
In-111
K-40
La-138
Pb-210
Pu-238
Pu-239
Ra-226
Ra-228
Sm-153
Sr-89
Sr-90
Th-228
Th-230
Th-232
Tl-201
Tl-202
U-234
U-235
U-238
Zn-65
Sludge Application Worker (years of application)
1
7.62E-03
4.42E-04
4.00E-05
1.71E-07
2.60E-05
2.05E-04
9.87E-03
1.27E-05
5.35E-03
2.25E-03
4.73E-03
8.81E-04
3.36E-07
2.05E-07
4.90E-05
2.73E-05
6.51E-04
5.08E-03
2.34E-05
3.75E-04
4.16E-04
7.41E-03
6.74E-03
1.78E-06
1.15E-06
1.67E-05
6.23E-03
2.63E-03
1.25E-02
3.28E-06
8.03E-05
1.23E-04
6.08E-04
1.94E-04
1.52E-03
5
3.57E-02
2.20E-03
4.04E-05
1.71E-07
2.60E-05
3.34E-04
3.83E-02
1.27E-05
1.52E-02
1.07E-02
2.03E-02
8.81E-04
3.36E-07
2.07E-07
4.90E-05
2.73E-05
2.21E-03
1.67E-02
1.23E-04
1.84E-03
2.08E-03
3.70E-02
4.21E-02
1.78E-06
1.16E-06
7.40E-05
1.71E-02
1.39E-02
1.76E-01
3.28E-06
8.03E-05
6.03E-04
2.98E-03
9.51E-04
2.34E-03
20
1.13E-01
8.64E-03
4.04E-05
1.71E-07
2.60E-05
3.36E-04
7.22E-02
1.27E-05
1.86E-02
3.56E-02
4.90E-02
8.81E-04
3.36E-07
2.07E-07
4.90E-05
2.73E-05
3.29E-03
2.37E-02
4.04E-04
6.88E-03
8.22E-03
1.47E-01
1.12E-01
1.78E-06
1.16E-06
1.97E-04
2.05E-02
6.75E-02
2.04E+00
3.28E-06
8.03E-05
2.24E-03
1.11E-02
3.54E-03
2.36E-03
50
1.89E-01
2.08E-02
4.04E-05
1.71E-07
2.60E-05
3.36E-04
7.72E-02
1.27E-05
1.86E-02
6.39E-02
6.02E-02
8.81E-04
3.36E-07
2.07E-07
4.90E-05
2.73E-05
3.34E-03
2.39E-02
6.88E-04
1.51E-02
2.01E-02
3.64E-01
1.27E-01
1.78E-06
1.16E-06
2.64E-04
2.05E-02
2.26E-01
7.26E+00
3.28E-06
8.03E-05
4.89E-03
2.42E-02
7.70E-03
2.36E-03
100
2.24E-01
3.92E-02
4.04E-05
1.71E-07
2.60E-05
3.36E-04
7.72E-02
1.27E-05
1.86E-02
8.15E-02
6.13E-02
8.81E-04
3.36E-07
2.07E-07
4.90E-05
2.73E-05
3.34E-03
2.39E-02
8.30E-04
2.46E-02
3.90E-02
7.14E-01
1.27E-01
1.78E-06
1.16E-06
2.76E-04
2.05E-02
6.40E-01
1.61E+01
3.28E-06
8.03E-05
7.91E-03
3.92E-02
1.24E-02
2.36E-03
ISCORS Technical Report 2004-04
6-11
Final, February 2005

-------
 Table 6.8    Land Reclamation, Landfill, and Incinerator Scenario DSR Values
             (mrem/y per pCi/g) for Screening Calculation C
Radionuclide
Ac-227
Am-241
Be-7
C-14
Ce-141
Co-57
Co-60
Cr-51
Cs-134
Cs-137
Eu-154
Fe-59
H-3
1-125
1-131
In-111
K-40
La-138
Pb-210
Pu-238
Pu-239
Ra-226
Ra-228
Sm-153
Sr-89
Sr-90
Th-228
Th-230
Th-232
Tl-201
Tl-202
U-234
U-235
U-238
Zn-65
Recreational User
2.35E-03
1.82E-04
4.58E-05
9.76E-02
3.33E-05
2.76E-04
1.10E-02
1.49E-05
6.41E-03
2.86E-03
5.36E-03
9.67E-04
4.51E-06
3.33E-05
6.23E-05
3.30E-05
7.17E-04
5.60E-03
8.28E-04
1.29E-04
1.45E-04
8.72E-03
7.37E-03
2.77E-06
1.51E-05
1.45E-03
6.51E-03
3.05E-03
1.24E-02
5.01E-06
9.54E-05
1.34E-03
2.15E-03
1.23E-03
2.35E-03
MSW Landfill
4.77E-11
3.72E-05
O.OOE+00
4.81E-05
O.OOE+00
O.OOE+00
2.95E-30
O.OOE+00
O.OOE+00
2.76E-10
2.70E-22
O.OOE+00
3.01E-07
O.OOE+00
O.OOE+00
O.OOE+00
9.19E-06
7.72E-04
2.54E-10
5.10E-07
5.58E-05
1.95E-03
5.93E-27
O.OOE+00
O.OOE+00
3.06E-11
O.OOE+00
8.95E-04
7.93E-03
O.OOE+00
O.OOE+00
7.32E-06
8.23E-06
3.71E-06
O.OOE+00
Landfill
Impoundment
2.48E-09
1.90E-03
O.OOE+00
6.02E-03
O.OOE+00
O.OOE+00
1.68E-28
O.OOE+00
O.OOE+00
1.39E-08
1.42E-20
O.OOE+00
1.66E-05
O.OOE+00
O.OOE+00
O.OOE+00
4.26E-04
4.45E-02
1.52E-08
2.52E-06
2.37E-03
8.88E-02
3.24E-25
O.OOE+00
O.OOE+00
1.58E-09
O.OOE+00
4.32E-02
4.06E-01
O.OOE+00
O.OOE+00
3.41E-04
3.36E-04
1.38E-04
O.OOE+00
Incinerator
Neighbor
1.18E+01
7.99E-01
1.09E-06
3.99E-07
3.02E-06
1.02E-04
7.97E-03
8.78E-07
6.69E-03
1.43E-02
4.34E-03
3.54E-04
3.17E-06
6.99E-02
1.31E-02
2.42E-07
4.81E-04
1.06E-02
4.74E-02
7.04E-01
7.74E-01
8.80E-02
2.53E-02
2.03E-07
4.70E-05
3.86E-02
5.23E-01
5.85E-01
2.97E+00
2.31E-07
4.74E-06
2.37E-01
2.22E-01
2.12E-01
2.28E-03
ISCORS Technical Report 2004-04
6-12
Final, February 2005

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Table 6.9    Indoor Radon Working Level Concentration
             per Unit Sludge Concentration for Screening Calculation C
             (WL per pCi/g)
Radionuclide
Ra-226
Th-228
Th-230
Th-232
U-234
Onsite Resident (Years of Application)
1
6.01E-06
3.36E-07
-
-
-
5
3.00E-05
9.27E-07
-
-
-
20
1.20E-04
1.11E-06
-
-
-
50
2.99E-04
1.11E-06
-
-
-
100
5.91E-04
1.11E-06
-
-
-
MSW
Landfill
1.48E-07
-
6.25E-08
6.47E-07
3.15E-10
Landfill
Impoundment
7.57E-06
-
3.32E-06
3.33E-05
1.68E-08
Table 6.10   Indoor Radon Concentrations
             per Unit Sludge Concentration for Screening Calculation C
             (pCi/L per pCi/g)
Radionuclide
(Daughter)
Ra-226 (Rn-222)
Th-228 (Rn-220)
Th-230 (Rn-222)
Th-232 (Rn-220)
U-234 (Rn-222)
Onsite Resident (Years of Application)
1
8.72E-04
1.45E-05
-
-
-
5
4.36E-03
4.00E-05
-
-
-
20
1.74E-02
4.77E-05
-
-
-
50
4.34E-02
4.77E-05
-
-
-
100
8.57E-02
4.77E-05
-
-
-
MSW
Landfill
1.93E-05
-
8.14E-06
3.64E-06
4.11E-08
Landfill
Impoundment
9.85E-04
-
4.32E-04
1.87E-04
2.19E-06
6.1.4     Interpretation of Measured Radon in Air

EPA has recommended that when homes or schools are tested for the presence of radon gas,
action be taken to reduce radon concentration levels if test results average 4 pCi/liter (or
0.02 working levels (WL)) or greater (EPA, 1994, EPA 2002, and EPA 2004). EPA
recommends, by this present publication, that the same action level used for homes and schools
should be utilized for POTWs. While exposure to radon in homes or schools is evaluated
differently than occupational  exposure, many nations and the ICRP (1993) also recommend that
intervention levels for exposure to radon in homes be utilized in workplaces (National Research
Council 1999). Methods used for radon detection were discussed previously in Section 5.3.

As discussed in Chapter 5, the operators of certain POTWs may want to determine whether there
are radon levels in air in enclosed areas in the plant that present elevated exposure to workers,
due to the applicability of various criteria identified in Section 5.2 (e.g., location of the POTW in
an area with high levels of naturally-occurring radioactive material).  To assess the potential for
excessive levels of radon exposure, the POTW operator should follow EPA recommendations for
testing and evaluating radon levels in homes and schools. These recommendations may be
summarized as follows:
ISCORS Technical Report 2004-04
6-13
Final, February 2005

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Step 1: Take an initial short-term test.
       If initial levels are at 4 pCi/liter or higher, perform Step 2.
Step 2: Take a short-term follow-up test where initial test results were 4 pCi/liter or higher.
       Take a long-term test in these locations for a better understanding of the annual average
       indoor radon level.
Step 3: Appropriate Follow-up Action.
       Take action to reduce levels if the average of the initial and short-term follow-up testing
       is 4 pCi/liter or greater, or the result of the long-term test is 4 pCi/liter or greater.
       Chapter 7 contains recommendations for appropriate actions to reduce levels of radon in
       the plant.

6.2   RECOMMENDATIONS  ON EVALUATING ESTIMATED DOSES
       DERIVED FROM SCREENING  CALCULATIONS

Where preliminary radionuclide sampling or monitoring data has been obtained, the POTW
operator should use the information contained in this guidance to determine what, if any,
additional steps or actions are warranted.  Potential doses should be estimated from the screening
calculations described in the previous section. These screening calculations are based on the
overall results of the ISCORS survey and dose modeling, and as a result, produce generally
conservative estimates of actual doses. Therefore, it is recommended that no further action by
the POTW operator is warranted where estimated doses are below 10 mrem/year. At estimated
doses above  10 mrem/year, the POTW operator should consult with the appropriate State
radiation protection regulatory agency (see Appendix E), and request guidance on whether any
next steps are necessary. The 10 mrem/year criterion is not a limit, does not include radon, and
is not intended to suggest that higher dose levels are unacceptable.

Consultation with the State agency may result in one of several recommendations, such as the
following, depending on the results of the screening calculation and on current sewage sludge or
ash management practices:

•   No additional steps need be taken.

•   Additional sewage sludge or ash samples are needed.
•   Additional indoor radon monitoring is needed.

•   A site-specific evaluation or a monitoring program is needed (see Section 6.3).

•   Another agency should be contacted for further guidance.?

•   A professional radiation protection specialist or a health physicist should be contacted for
    assistance in designing a monitoring program or evaluating existing management practices.

•   Possible changes in management practices that would reduce exposures should be evaluated.
   The EPA may be consulted on NORM and TENORM sources, concentrations, or dose estimates. If the
   estimated annual dose is 25 mrem or more, based on concentrations of Source and By-Product material only,
   the NRC should be consulted.
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6.3    CONDUCT A SITE-SPECIFIC EVALUATION THAT MAY INVOLVE
       ADDITIONAL SURVEYS OR SAMPLING OF THE POTW, POTW
       PERSONNEL, AND/OR USE OR DISPOSAL SITES.

If screening calculations suggest that potential doses to workers (within the POTW or those who
handle sewage sludge or ash outside of the POTW) may be above the acceptable radiation dose
level (as determined after consultation with the State agency), the POTW operator may want to
conduct a more thorough evaluation of the levels detected in the sludge, ash, or indoor air, based
on site-specific conditions.  This evaluation may involve additional sampling or monitoring, use
of modeling scenarios developed for the ISCORS dose modeling project and substitution of
actual site-specific input data, creation of more directly applicable modeling scenarios than those
used in the ISCORS dose modeling project, or actual physical surveys of potentially affected
areas of the POTW or other sludge management locations. Results of the surveys of sludge
management locations should be reported to the State radiation control program to determine the
appropriate standards for comparison.

6.3.1     Evaluate  Any Potential External Radiation Exposure of
          Collection System Workers or POTW Personnel

There may be a potential for external radiation exposure (i.e., from outside the body, rather than
from ingestion or inhalation) to collection system workers and POTW personnel if elevated
levels of gamma-emitting radionuclides are discharged into the wastewater system (more
information regarding the various types of radionuclides is provided in Appendix A). If there is
the potential for such discharges, the POTW  should consider such an evaluation. This evaluation
may be conducted using two methods: (1) use a radiation survey meter to identify any points at
which such contamination exists, and  (2) use an integrating radiation measuring device to
determine if any exposures could occur over  time.  It is advisable to hire a health physics
consultant to assist in the selection of appropriate survey methods and instruments.

In planning and conducting a radiological survey at a POTW, the following guidelines should be
considered:

•  Direct measurement can be conducted with an instrument using a sodium iodide detector
   tube or a very sensitive Geiger Muller detection device. The instrument should be able to
   detect gamma radiation in the micro-roentgen per hour range.

•  In taking measurements along the  collection system, it is best to focus on system junctions
   and bends that are immediately downstream from the wastewater generator of concern.
   These are points that allow the accumulation of radioactive material. Prior to taking
   collection system measurements, it is important to create a baseline of the background
   radiation levels;  a background measurement should be taken in the general vicinity of the
   system before taking measurements in the collection system itself. If possible, these
   background measurements should be taken upstream of the discharger over grassy areas.
   Table 3.4 provides typical ranges of radioactive material concentrations found in U.S. soils
   and common items such as fertilizers and building materials, as well as the range of
   radioactive material concentrations detected during the pilot survey of sludges  and ash from
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   nine POTWs.  This table is taken from Appendix B of the pilot survey report (NRC and
   EPA 1999) and the ISCORS Survey Report (ISCORS 2002).

•  If there is reason to believe that collection system workers may be exposed to elevated levels,
   then appropriate monitoring of the collection system may be necessary. Monitoring down
   manholes in the collection system may result in highly variable measurements.  These
   variations may be a few times the background levels and may result from the construction
   materials used in the manhole. Marked variations may be observed between concrete and
   brick, or even among different concrete or brick materials. These variations are largely due
   to the natural radioactive materials in the construction materials.  If elevated values are
   found, further investigation may be warranted.  Consultation with the radiation  regulatory
   authority is recommended. More detailed information on this issue may be found in the
   National Biosolids Partnership guidance (NBP 1999).

•  At the POTW, direct radiation measurements should be taken at locations where solid
   materials accumulate, including grit chambers and points of sludge collection.  If incineration
   of sludge is performed, the residual ash should also be measured. Background  measurements
   should be made away from the sludge collection point.  Some variability in measurements
   can be expected. These measurements are necessary to compare levels in sewage sludge and
   ash samples.

•  To identify changes over time, POTW operators may also want to employ an integrating
   measurement device that accumulates radiation exposure over time. It is also possible to
   periodically conduct follow-up surveys using direct radiation measurements; however,
   integrating measurement devices are more effective for time analyses.

•  Although there are expensive self-recording  types of devices available, it may be more cost
   effective to use some thermoluminescent dosimeters (TLD). These devices are crystal
   structures that store the energy imparted by incident radiation so that it can be subsequently
   measured to evaluate the exposure received.  The selection of the particular TLD to use
   should be made after consultation with the vendor, including a discussion of the particular
   use intended.

•  The locations selected for placing the TLDs  should be determined carefully, in  a manner
   similar to the location selection process for the direct radiation measurements.  Several of the
   TLDs should be placed in an area removed from sludge processing (e.g., an office  desk,
   cabinet) to serve as a background measurement. The TLD devices used for system
   measurements can be hung down manholes or over areas where sludge is collected, or over
   conveyer belts where sludge is transported.  The TLDs should be left in place for a period of
   a few weeks to a month and then returned to the vendor for evaluation.

A source of useful information on such surveys is a Federal consensus document, Multi-Agency
Radiation Survey and Site Investigation Manual (MARSSIM).  This manual may provide useful
information on planning and conducting a survey involving potential contamination of surface
soils and building surfaces. This manual, prepared  specifically for site surveys involving
radiological contaminants,  contains useful information on sampling procedures, field
measurement methods and instrumentation, quality assurance and quality control procedures and
interpretation of results. This information was developed as a consensus approach  by four
Federal  agencies (EPA, DOE,  NRC, and DOD) to determine whether dose or risk-based release

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criteria for buildings and soils have been met.  In the context of a POTW survey for radiological
contaminants, the methods and procedures contained in this manual should be generally
applicable. The MARSSEVI document and related informational tools can be obtained from the
EPA's Office of Radiation website (http://www.epa.gov/radiation/marssim/).

As previously noted, the POTW operator should consult a qualified health physicist for
assistance in designing a sampling and analysis program.

6.3.2    Evaluate Any Potential External Radiation Exposure of Sludge
          Management Workers or the General Public

In addition to evaluating the potential for exposures to POTW workers from exposure to
radioactive materials where sewage sludge and ash is managed within the plant, the POTW
operator may also need to evaluate potential exposures to other workers who handle or manage
sewage  sludge and ash outside of the plant or to members of the public. If a thorough survey of
sludge accumulation points at the POTW indicates that potential exposures are below levels of
concern, there is a reduced probability that radionuclide levels in  soils at land application sites
will be elevated. Also, if the screening calculations performed in Section 6.1 are below the
10 mrem/year consultation level, then there is a reduced probability that radionuclide levels in
soils at a disposal or land application site will be elevated. However, materials placed in these
sites in the past may have resulted in a buildup  of radioactive material that would not have been
detected otherwise.

A survey of land application sites where sludge has been  disposed is a prudent  step if there is
reason to believe that elevated levels of radioactive  materials may have been discharged to the
system.  Measurement of radiation levels in these areas can be made with the same instrument
used for the collection and treatment systems.  Background levels should be  measured in areas
without sewage sludge or ash for comparison purposes. Some variation in background levels
should be expected due to local soil conditions. If levels  significantly above background are
found, it is suggested that the appropriate radiation control authority be consulted.

In cases where the POTW operator or a contractor uses or disposes of sewage sludge or ash, the
following factors may be considered to decide whether to perform measurements at the use or
disposal sites:

•  Indications that radioactive materials had been discharged to the treatment system and had
   entered the POTW.

•  The liability arrangements between the POTW and the contractor.

•  The adequacy of available records on past sewage sludge/ash  applications.

•  The frequency and amount of sewage sludge/ash applications to each site.

•  The results of the screening calculations of Section 6.1.

If the results of the screening calculations are above the 10 mrem/year consultation level, but the
gamma  survey results are negative, the POTW  operator should consider taking soil samples at
the land application site, after consultation with appropriate Federal and State authorities.

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6.3.3    How to Evaluate Any Potential Radiation Exposure within the
          POTW

Following the steps described above, any significant occurrence of radioactive materials at a
collection system or within the POTW should have been detected. If there is a determination of
potential significant exposure from the direct radiation measurements, a determination of the
source of the radioactive material should be made.  Such a determination would also be
necessary to identify the possibility of ingestion or inhalation of radioactive material during
wastewater collection and treatment, or sewage sludge and ash use or disposal practices. In these
cases, it may be necessary to take physical samples of the sewage sludge, ash, or other residual
material and have this material analyzed at a laboratory with the capability for such an
assessment. Other cases where sampling and analysis may be required are circumstances where
the source of the radioactive material is not detectable by the methods  previously described.
These would be instances where the radiation emitted was only alpha or weak beta radiation.
Such radioactive materials include some man-made elements that are heavier than uranium, and
more common radioactive materials, such as hydrogen-3 (tritium) and carbon-14.
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7  WHAT CAN  BE DONE TO REDUCE RADIATION DOSES
   AND RADON LEVELS?

As discussed in Section 6.2, POTW operators should determine the appropriate course of action
to reduce radiation doses and radon levels through consultation with radiation regulatory
authorities and health specialists, if estimated doses exceed 10 mrem/year. Actions may include
reducing levels of radioactivity at the source or reducing exposure to sludge. In rare cases,
corrective actions may be needed for contaminated equipment or disposal sites.

7.1   CONTACT REGULATORY AGENCIES FOR ASSISTANCE

If estimated radiation doses or radon concentrations are above recommended levels
(i.e., 10 mrem/year for non-radon exposures or 4.0 pCi/liter for radon), the POTW operator
should consult with State radiation regulatory agencies (see Appendix E). Based on the initial
contact with the State, the POTW operator may also need to contact the NRC regional office or
the EPA regional office Radiation Program Manager (see Appendices C and D, respectively).
These regulatory agencies are valuable sources of information on radiation and radiation
protection and may assist the POTW operator in addressing the situation and in communicating
with the public. They can also help identify possible sources  of the radionuclides,  assist in
establishing an appropriate course of action, and take enforcement actions if needed to correct
the situation.

The regulatory agency may determine that the levels are not sufficiently elevated to cause
concern for worker or public health and safety. In that case, no additional action by the POTW
would be needed to protect workers. However, the POTW operator should convey the
regulator's findings to the POTW workers so that they know there is no cause for concern. A
letter or other documentation from the regulator would be useful in communicating with workers
that the levels do not pose a concern.

7.2   CONTROLLING SOURCES OF RADIONUCLIDES ENTERING THE
      POTW

POTW operators, in consultation with the regulatory  agencies, should determine what can be
done to control sources of radionuclides entering the POTW.  Each situation will be unique and
the appropriate actions will vary from no additional action to  regulatory enforcement.  The
approach taken will be affected by the answers to several questions that the POTW operator and
the regulator  may explore.

1. Where did the radionuclides come from?  Consultation with the regulatory agency could
   identify whether the radionuclides are naturally-occurring, TENORM, or man-made. (See
   Section 3.1 for a description of these types of sources.) For man-made sources, the presence
   of specific radionuclides could help regulators determine if a licensee is the source.
2.  How did the radionuclides get to the POTW? As discussed in Section 3.2, radionuclides may
   reach the  sewers and POTW in several ways.  For example, radionuclides may enter the
   POTW via discharges, POTW treatment processes, or infiltration and inflow.  To determine


ISCORS Technical Report 2004-04               7-1                         Final, February 2005

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   the location of discharges that may cause contamination, the POTW operator may need to
   take samples from the sewers leading from the sources.  The necessity of sampling should be
   discussed with the NRC or State contact prior to initiation.  Based on this information, the
   POTW operator should be able to determine the source(s) of any radioactive materials that
   may enter the POTW.
3.  How often are radionuclides expected to reach the POTW? Knowing the timing of releases
   enables POTW operators to plan for their arrival. For example, some users of radioactive
   materials are allowed to continuously or intermittently release small amounts of
   radionuclides to the sewer system. Accidental discharges may only occur once or
   infrequently. Naturally occurring radionuclides may reach the POTW continuously or
   periodically following precipitation events that increase infiltration and inflow.
4.  Who is responsible for controlling the sources of the radionuclides? Regulatory agencies are
   responsible for setting license conditions and limits to protect human health.  Licensees are
   responsible for operating or handling their materials in accordance with regulations and their
   license conditions. Landowners may be responsible for controlling erosion that carries
   natural sources into the sewer system through inflow. POTW operators are responsible for
   maintaining an effective infiltration and inflow program, which could reduce the potential for
   natural sources to reach the POTW.
5.  Are the appropriate controls  in place to minimize releases of radionuclides to the POTW?
   The POTW operator may want to evaluate the effectiveness of the controls used by the
   discharger to minimize releases of radionuclides. The POTW operator may need to consult
   with the regulatory agency to review the regulations and license conditions imposed on a
   discharger, or their implementation by the discharger. The POTW operator should review
   infiltration and inflow controls if that is the source.

The POTW operator can work with the regulator to decide on appropriate actions to prevent
reoccurrences. The following include examples of these actions:

•  Consult directly with likely industrial dischargers who may be routinely discharging
   radioactive material to the sewer system, to explore the possibility of voluntary reductions in
   such discharges.

•  Encourage use of spill prevention measures to reduce the potential for accidental releases.

•  Impose appropriate additional local controls on the discharger, such as local discharge limits
   and regular reporting of discharges.

•  Require notification of planned or accidental discharges, or request that notification from the
   source facilities when future releases occur. Notification would enable the POTW to monitor
   the condition at the POTW and take measures to protect workers if necessary. POTW
   operators may lack the authority to require notification, but could request it as a voluntary
   measure by the user and consult with the Local Emergency Planning Committee (LEPC) and
   State Emergency Response Committee (SERC).

•  Request that regulators take enforcement action against dischargers who violate license
   conditions and contribute to the elevated levels.
ISCORS Technical Report 2004-04                7-2                            Final, February 2005

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•  Provide regulators with information on interferences in operating practices created by the
   dischargers. This information may be useful for the regulator in deciding whether to modify
   the release limits.

•  Correct infiltration and inflow problems that transport naturally-occurring radionuclides to
   the POTW especially pressure driven radon gas.

If the release was a one-time accident and future releases are unlikely, action to prevent
reoccurrence may not be needed.

7.3    REDUCING EXPOSURE  TO RADIOACTIVITY FROM SLUDGE

When there are elevated levels of radioactivity, the most important concern for the POTW
should be the protection of the workers and the public.

7.3.1     Reducing Exposure at the POTW

If consultations with the regulatory agency indicate there may be a concern regarding exposure
to the POTW workers, the POTW may need to obtain the services of a qualified consultant, such
as a health physicist, to evaluate the radiation levels at the plant and disposal sites. The
consultant can recommend appropriate protective measures that are commensurate with the
radiation hazards to keep exposure levels as low as reasonably achievable.  These measures may
include:  increasing the distance between workers and the radiation source(s); increasing the
shielding between the source(s) and the workers; increasing ventilation rates in areas where
radium and radon may be present; provide appropriate equipment and health and safety training
to potentially affected workers; and  limiting the amount of time workers spend near units with
elevated levels of radioactive materials.

As mentioned earlier, OSHA occupational radiation standards (see 29 CFR 1910.1096) might
apply whenever an  operator becomes aware of the presence of radiation at the facility. Although
these standards may not apply to municipal wastewater treatment plant workers, workers could
be covered by their State OSHA program, requiring that all controls, monitoring, recordkeeping,
and training outlined in the OSHA standards be met.

Many of the measures that protect workers from radiation hazards are the same as those used at
POTWs to protect against pathogens. State health or occupational safety agencies, or OSHA
safety and health regulations and guidances for radiation exposures may be available or
applicable.  Personal hygiene practices such as washing hands before eating, drinking, or
smoking prevents ingestion of radionuclides as well as pathogens. Similarly, the use of personal
protection equipment (or PPE, for the eyes, face, head, and extremities) such as protective
clothing , respiratory devices, and protective shields and barriers should be provided, if elevated
levels of radiation warrant, in dusty  sewage sludge and ash handling areas to reduce the potential
for health risks from inhaling dust and any radionuclides associated with the dust, although such
measures would not protect against radon.  Restrictions to limit personnel entry, or employee
time spent in areas with elevated radiation levels could also be recommended if the radiation
evaluations of the facility warrant. Additional safety measures are provided in Appendix A.
ISCORS Technical Report 2004-04                7-3                           Final, February 2005

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Elevated levels of radon gas in indoor air, where average concentrations of Ra-222 exceed
4 pCi/liter, or total radon levels (Ra-220 and Ra-222 combined) exceed 0.02 WL, may indicate
that best management practices are warranted.  There are a number of actions that the POTW
operator may want to consider:

1.  Evaluate the possibility of increasing ventilation and air exchange.
2.  It may be feasible to decrease worker time spent in confined areas where sludge is managed.
3.  It may be prudent to continue monitoring indoor locations for radon where sewage sludge
   and ash are processed or stored.
4.  The POTW operator should take into account the possibility of radon entering the building
   from sources other than sewage sludge or ash.

POTW operators are encouraged to consult with regulatory agency personnel or a health physics
consultant for assistance in interpreting measured radon levels in the POTW.

The POTW operator may need to consult with the regulatory agency and other experts such as
those certified by the American Society of Heating, Refrigerating, and Air-Conditioning
Engineers about possible ways of increasing ventilation and air exhaust for the affected
location(s). States with radon certification programs may be contacted to obtain information on
certified radon mitigation contractors.

If elevated levels of radioactivity have been identified, the POTW employees should be
informed.  The POTW employees should also be provided with factual information on the risks
associated with the level of radiation exposure.  Regulatory agencies or health physicists may
have literature available to assist in communicating with POTW personnel, particularly if
occupational radiation safety rules have been adopted by State agencies that may be applicable to
municipal facilities.

7.3.2     Reducing Exposure Outside the POTW

In evaluating levels  of radioactive materials in sewage  sludge or ash that is managed through any
type of land application process, it is possible that potential future sources of exposure may be
indicated through various dose modeling scenarios.  This situation may occur, for example, if the
land application site is eventually converted to another type of land use, particularly one with
minimal restrictions, such as residential development.  Where such future exposures may be a
concern, the POTW  operator may want to re-evaluate existing management practices to avoid
creating an unacceptable exposure scenario. Rather than continuing to apply sewage sludge or
ash on  an on-going basis to a dedicated land application site, the POTW operator may want to
consider the following:

•  Reduce the number of years  of application to the same site;

•  Reduce the frequency of applications to the same site;

•  Increase holding times at the POTW before land application, which would allow for decay of
   radionuclides with relatively short half-lives;
ISCORS Technical Report 2004-04                7-4                           Final, February 2005

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•  Divert sludge management from land application to landfill disposal or land reclamation;

•  Consider other alternative sludge use or disposal practices, where land use restrictions may
   be more feasible and effective.

Monofills, which are landfills with trenches that are used for disposal of sewage sludge and ash
only, were not specifically evaluated for radiation doses in the ISCORS dose assessment study.
ISCORS believes that such a site, if it had received sewage sludge or ash for burial with elevated
radiation levels, should be surveyed for radiation levels before consideration for future land
transfer or sale for other uses, such as residential construction. Restrictions on transfer or future
land use, and or site remediation might be required if radiation levels have been elevated.

7.4    CORRECTIVE ACTIONS FOR CONTAMINATED AREAS

In rare instances, sewage sludge and ash management may cause contamination of equipment or
disposal or land application sites.  If this situation occurs, the POTW operator may be
responsible for removing the contamination. Consultation with the regulatory agencies (see
Appendix D for contact information for EPA's Regional Offices) should be pursued to determine
any requirements that may apply.

Cleanup of contaminated sites can be a costly endeavor for the POTW.  Depending upon the
applicable Federal and State laws, some dischargers may be liable for portions of the cleanup
costs if their discharges caused the contamination.  Legal counsel should be consulted as to
whether any dischargers may be liable for portions of the cost.
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8  COMMENTS OR QUESTIONS ON THIS REPORT

If you have any questions or comments regarding this report, please contact either NRC or EPA.

U.S. Environmental Protection Agency contact:

      Robert Bastian
      U.S. Environmental Protection Agency - 4204M
      1200 Pennsylvania Avenue, NW
      Washington, DC 20460-0001
      phone: (202)564-0653
      e-mail: bastian.robert@epa.gov
U.S. Nuclear Regulatory Commission contact:

      Duane Schmidt
      U.S. Nuclear Regulatory Commission
      Decommissioning Directorate
      MailStopT-7E18
      Washington, DC 20555-0001
      phone: (301)415-6919
      e-mail: dws2@nrc.gov
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9  REFERENCES

Ainsworth, C.C., R.L. Hill, KJ. Cantrell, D.I. Kaplan, M.V. Morton, R.L. Aaberg, and
E.A. Stetar, 1994, Reconcentration of Radioactive Material Released to Sanitary Sewers in
Accordance with 10 CFRPart 20, Rep. NUREG/CR-6289, PNL-10193, U.S. Nuclear
Regulatory Commission.

American National Standards Institute/Health Physics Society, 1999, ANSI Surface and Volume
Radioactivity Standard for Clearance (N13.12-1999).

DOE (Department of Energy), 1990, Radiation Protection of the Public and the Environment,
DOE Order 5400.5, Office of Environment,  Safety and Health, June 5, 1990.

Eisenbud M. and T. Gesell, Environmental Radioactivity, Fourth Edition (1997), Academic
Press, San Diego, CA.

EPA (Environmental Protection Agency), 1986, Radioactivity of Municipal Sludge, Office of
Water Regulations and Standards, Washington, DC.

EPA (Environmental Protection Agency), 1989, POTWSludge Sampling and Analysis Guidance
Document. EPA 833/B-89-100, Office of Water (4203),  Washington, DC.

EPA (Environmental Protection Agency). National Pretreatment Program, Report to Congress.
21W-4004 (July 1991). Office of Water (EN-336), Washington, DC.

EPA (Environmental Protection Agency), 1993 a, EPA 'sMap of Radon Zones: National
Summary, Rep. 401-R-93-071, Office of Air and Radiation, Washington, DC.

EPA (Environmental Protection Agency), 1994, Radon Measurements in Schools-Revised
Edition. Office of Air and Radiation, Washington, DC.

EPA (Environmental Protection Agency), 2002, A Citizen's Guide to Radon. 402-K02-006.
(Revised May 2002). Office of Air and Radiation, Washington, DC.

EPA (Environmental Protection Agency), 2004, A Citizen's Guide to Radon. 402-K02-006.
(Revised May 2004). Office of Air and Radiation, Washington, DC.

Fisher, Eugene, 2003, U.S. EPA, Office of Radiation and Indoor Air, Personal Communication.

GAO (Government Accountability Office),  1994, Nuclear Regulation; Action Needed to Control
Radioactive Contamination at Sewage Treatment Plants, Rep. GAO/RCED-94-133.

Huffert, A.M., R.A. Meek, and K.M. Miller, 1994, Background as a Residual Radioactivity
Criterion for Decommissioning, Rep. NUREG-1501, U.S. Nuclear Regulatory Commission.

ISCORS 2003. Joint NRC/EPA Sewage Sludge and Ash Project: Radiological Survey Results
and Analysis. Rep. ISCORS 2005-04.
ISCORS Technical Report 2004-04               9-1                          Final, February 2005

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ISCORS 2004. ISCORS Assessment of Radioactivity in Sewage Sludge: Modeling to Assess
Radiation Doses. Rep. ISCORS 2005-03, NUREG-1783, EPA 832-E-03-002A, DOE/EH-0670.

Kennedy, W.E., M.A. Parkhurst, R.L. Aaberg, D.C. Rhoads, R.L. Hill and J.B. Martin, 1992,
Evaluation of Exposure Pathways to Man from Disposal of Radioactive Materials into Sanitary
Sewer Systems, Rep. NUREG/CR-5814, PNL-7892, U.S. Nuclear Regulatory Commission.

Kozinski, J., Z. Szabo, O.S. Zapecza, and T.H.  Barringer, 1995, Natural Radioactivity in, and
Inorganic Chemistry of, Ground Water in the Kirkwood-Cohansey Aquifer System, Southern
New Jersey,  1983-89, US Geological Survey Water-Resources Investigations Report 92-4144,
West Trenton, NJ.

MacQueen, D., G. Gallegos, and K. Surano, 2002. Livermore Big Trees Park:  1998 Results,
Lawrence Livermore National Laboratory, (UCRL-ID-143311).

Murray, I.P.C., and PJ. Ell, 1998, Nuclear Medicine in Clinical Diagnosis and Treatment,
Volumes 1 and 2.  Churchill, Livingstone.

National Academy of Sciences, Board on Radiation Effects Research, 1999, Evaluation of
Guidelines for Exposures to Technologically Enhanced Naturally Occurring Radioactive
Materials.

NBP (National Biosolids Partnership), 1999, Characteristics of Radioactivity Sources at
Wastewater Treatment Facilities, NBP Rep. No. 1, Water Environment Federation, Alexandria,
Virginia.

NCRP (National Council on Radiation Protection and Measurements),  1976 Environmental
Radiation Measurements, NCRP Report No. 50, Bethesda, MD.

NCRP (National Council on Radiation Protection and Measurements),  1987a, Ionizing Radiation
Exposure of the Population of the United States, NCRP Report No. 93. Bethesda, MD.

NCRP (National Council on Radiation Protection and Measurements),  1987b, Radiation
Exposure of the U.S. Population from Consumer Products and Miscellaneous Sources, NCRP
Report No. 95. Bethesda, MD.

NCRP (National Council on Radiation Protection and Measurements),  1993, Limitation of
Exposure to Ionizing Radiation, NCRP Report No. 116,  Bethesda, MD.

NRC (Nuclear Regulatory Commission),  1991, 10 CFRPart20, Standards for Protection
Against Radiation. Washington, DC.

NRC, June 2001, Systematic Radiological Assessment of Exemptions for Source and Byproduct
Materials, NUREG-1717. Washington, DC.

NRC (Nuclear Regulatory Commission),  10 CFR Part 30, Rules of General Applicability to
Domestic Licensing of Byproduct Material. Washington, DC.
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NRC and EPA (Nuclear Regulatory Commission and Environmental Protection Agency),
December 1997, Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM),
NUREG-1575 and EPA 402-R-97-016. Washington, DC.

NRC and EPA (Nuclear Regulatory Commission and Environmental Protection Agency), May
1999, Joint NRC/EPA Sewage Sludge Radiological Survey: Survey Design and Test Site Results,
Rep. EPA 832-R-99-900, prepared by the Sewage Subcommittee of the Interagency Steering
Committee on Radiation Standards, NRC and EPA, Washington, DC.

Szabo, Zoltan and dePaul, V.T., 1998, Radium-226 andRadium-228 in Shallow Ground Water,
Southern New Jersey: U.S. Geological Survey Fact Sheet FS-062-98, p. 6.

Tykva R. and J. Sabol, Low-Level Environmental Radioactivity - Sources and Evaluation,
Technomic Publishing Company, Inc., Lancaster, Pennsylvania (1995).

US Geological Survey/US Environmental Protection Agency, Occurrence of Selected
Radionuclides in Ground Water Used for Drinking Water in the United States: A
Reconnaissance Survey, 1998.  Report 00-4273 (1998). Washington, DC.

Wisconsin Department of Natural Resources (DNR), Fate andMobility of Radium-226 in
Municipal Wastewatery Sludge Following Agricultural Landspreading - A Survey.  Madison,
WI. PUBL-WW-00687.

WSSC (Washington Suburban Sanitary Commission), October 1995, Radioactive Waste
Disposal Risk Study. Washington, DC.
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APPENDIX A
FUNDAMENTALS OF RADIATION

What is Radiation?

Radiation is energy in the form of high speed particles and electromagnetic waves (photons) that
are released from unstable atoms. Radiation with enough energy to separate molecules or
remove electrons from atoms is known as ionizing radiation. Non-ionizing radiation does not
have enough energy to remove electrons from their orbits.  Radioactivity is the property that
some unstable atoms exhibit in the process of undergoing spontaneous transformation, decay, or
disintegration, which  emits radiation. Materials that contain radioactive atoms are known as
radioactive materials.

Radiation is in every part of our lives. It occurs naturally in the earth and can reach us through
cosmic rays from outer space. Radiation may also occur naturally in the water we drink or the
soils in our backyard. It even exists in food, building materials, and in our own human bodies.
Radiation is used for scientific purposes, medical reasons, and power (e.g., the U.S. Navy uses
radiation to power submarines through the water).  People also come into contact with radiation
through man-made sources such  as X-rays, nuclear power plants, and smoke detectors.

The radiation of interest in this guidance is ionizing radiation. At excessive levels, the process of
ionization can cause disease and  injury to plants and animals.  The three most common types of
ionizing radiation are:

•  Alpha radiation - positively charged particles that are emitted from naturally-occurring and
   man-made radioactive material.  The alpha particle has the least ability to penetrate other
   materials. Most alpha particles can be stopped by a single sheet of paper or the top layer of
   skin.  Consequently, the principal hazard from  alpha emitters to humans occurs when the
   material is ingested or inhaled.  The limited penetration of the alpha particle means that the
   energy of the particle is deposited within the tissue (e.g., lining of the lungs) nearest the
   radioactive material once inhaled or ingested. Examples of alpha emitters are radon,
   thorium, and uranium.

•  Beta radiation - negatively charged particles (electrons) that are typically more penetrating
   but have less energy than alpha particles. Beta particles can penetrate human skin or sheets
   of paper, but can usually be stopped by thin layers of plastic, aluminum, or other materials.
   Carbon-14 and hydrogen-3 (or tritium) are two common beta emitters. Although they can
   penetrate human skin, beta particles are similar to alpha particles in that the predominant
   hazard to humans comes from ingesting or inhaling the radioactive materials that emit beta
   radiation.  Other examples of beta emitters are  phosphorus-32 and strontium-90.  Some
   radioactive materials  emit positively charged electrons, or positrons.
•  Gamma (or X-ray) radiation - the most penetrating type of radiation.  They can pass through
   the human body and common construction materials. Thick and dense layers of concrete,
   steel, or lead are used to stop gamma radiation  from penetrating to areas where humans can
   be exposed.  Gamma emitters can pose both external and internal radiation hazards to
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   humans. Technetium-99m is an example of a gamma emitter that is widely used in medical
   diagnosis.  Other gamma emitters include thallium-201 and selenium-75.
Some radionuclides emit more than one type of radiation.  For example, cesium-137 and
iodine-131 are both gamma and beta emitters. Potassium-40, a common naturally-occurring
radionuclide, is also a beta/gamma emitter.  Radium-226 emits both alpha and gamma radiation.

How is Radiation Measured?

Whether it emits alpha or beta particles or gamma rays, the quantity of radioactive material is
typically expressed in terms of its radioactivity or simply its activity and is measured in curies.
One  curie equals 37 billion atomic disintegrations per second.  Activity is used to describe a
material, just as one would discuss the length or weight of a material.  For example, one would
say "the activity of the uranium in the container is 2 curies." Generally, the higher the activity of
the material, the greater the potential health hazard associated with that material if it is not
properly controlled. At nuclear power reactors, the activity of radioactive material may be
described in terms of hundreds to millions of curies, whereas the units typically used to describe
activity in the environment and at POTWs are often microcuries  (• Ci) or picocuries (pCi).  A
microcurie is one one-millionth (1/1,000,000) of a curie and a  picocurie is one one-trillionth
(1/1,000,000,000,000) of a curie.

The activity of a radionuclide decreases or decays at a constant rate. The time it takes the
activity of a radioactive material to decrease by half is called the radioactive half-life. After one
half-life, the remaining activity would be one-half (2) of the original activity. After two
half-lives, the remaining activity would be one fourth (1/4), after three half-lives one eighth, and
so on.  For example, if a radionuclide has a half-life of 10 years,  the amount of material
remaining after 10 years would be 2 of that originally present.  After 100 years (10 half-lives),
the remaining activity would be 1/1024 of the amount that was originally present.  Some
radioactive materials have extremely short half-lives measured in terms of minutes or hours; for
example, technetium-99m, used in medical procedures, has a half-life of 6 hours. Others have
half-lives measured in terms of millions to billions of years; for example, naturally occurring
thorium-232 has a half-life of 14 billion years, and natural uranium-238 has a half-life of 4.5
billion years. Half-lives for a number of radionuclides are shown in the following table.
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 Table A.1    Radionuclides Included in the ISCORS Dose Assessment
             (ISCORS 2003)
Radio-
nuclide
Ac-227c
Ac-228d
Am-241
Be-7c
Bi-212d
Bi-214d
C-14
Ce-141
Co-57
Co-60
Cr-51a
Cs-134
Cs-137
Eu-154
Fe-59
H-3
1-125
1-131"
In-llla
K-40
La-138a
Np-237b
Pa-231b
Pa-234md
Pb-210
Pb-212d
Pb-214d
Major
Radiations
alpha, beta, gamma
beta, gamma
alpha, gamma
gamma
alpha, beta, gamma
beta, gamma
beta
beta, gamma
gamma
beta, gamma
gamma
beta, gamma
beta, gamma
beta, gamma
beta, gamma
beta
gamma
beta, gamma
gamma
beta, gamma
beta, gamma
alpha, gamma
alpha, gamma
beta, gamma
beta, gamma
beta, gamma
beta, gamma
Half-life
22 years
6 hours
432 years
53 days
61 minutes
20 minutes
5730 years
33 days
271 days
5 years
28 days
2 years
30 years
9 years
45 days
12 years
60 days
8 days
3 days
1.3xl09 years
135><109 years
2.14xl06 years
32.8xl03 years
1 minute
22 years
1 1 hours
27 minutes
Radio-
nuclide
Po-210b
Pu-238
Pu-239
Ra-223d
Ra-224d
Ra-226
Ra-228
Rn-219d
Sm-153a
Sr-89
Sr-90
Th-227d
Th-228
Th-229b
Th-230
Th-232
Th-234d
Tl-201a
Tl-202a
Tl-208d
U-233b
U-234
U-235
U-238
Xe-131mb
Zn-65

Major
Radiations
alpha
alpha
alpha
alpha, gamma
alpha, gamma
alpha, gamma
beta
alpha, gamma
beta, gamma
beta
beta
alpha, gamma
alpha, gamma
alpha, gamma
alpha
alpha
beta, gamma
gamma
gamma
beta, gamma
alpha
alpha
alpha, gamma
alpha
gamma
beta, gamma

Half-life
138 days
88 years
24xl03 years
1 1 days
4 days
1600 years
6 years
4 seconds
47 hours
51 days
29 years
19 days
2 years
7,340 years
77xl03 years
14xl09 years
24 days
3 days
12 days
3 minutes
158.5 xlO3 years
245xl03 years
700xl06 years
4.5xl09 years
12 days
244 days

Notes:
Information on daughters for standard RESRAD radionuclides is included in Table 3. 1 of the RESRAD manual (Yu et al., 2000).
a This radionuclide is not included in standard RESRAD, and was added as input to the code specifically for this project.
b Although this nuclide was not identified in the previous survey (EPA 1999), it is included in the dose assessment because it is a principal
nuclide and its parent nuclide is included in the analysis. Am-241 decays to Np-237, U-233, and Th-229; U-235 decays to Pa- 231;
Pb-210 decays to Po-210; and 1-131 decays to Xe-131m.
c Although this nuclide was not identified in the previous survey (EPA 1999), it is included in the assessment because it is the parent
nuclide and its daughter nuclides are included in the analysis. Ac-227 is the parent nuclide of Ra-223, Rn-219, and Th-227.
d Radiological dose for this radionuclide is included in the dose of its parent nuclide. The parent nuclides are Ra-228 for Ac-228; Th-228
for Bi-212, Pb-212, Ra-224, and Tl-208; Ra-226 for Bi-214 and Pb-214; U-238 for Pa-234m and Th-234; and Ac-227 for Ra-223,
Rn-219, and Th-227.
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Some radioactive materials decay to form other radioactive materials. These decay products, in
turn, decay, eventually forming stable nuclides. Each material formed through decay has a
unique set of radiological properties,  such as half-life and energy given off through decay. In the
case of the radioactive materials found at POTWs, the radioactive materials present may consist
of one or more separate decay "chains" or "series." The naturally-occurring uranium, actinium,
and thorium decay chains are illustrated in Figures A.I, A.2, and A.3.
Figure A.I    Uranium (  U) Decay Series
Figure A.2    Actinium (235U) Decay Series
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Final, February 2005

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Figure A.3    Thorium (232Th) Decay Series

Some of the radioactive materials in these chains emit gamma rays when they decay.  The
intensity of gamma radiation in air or exposure rate is measured in roentgens (R) or
microroentgens (|iR) per unit time, usually an hour, as in R/hr or |iR/hr. In the environment,
exposure rates are typically measured in terms of |iR/hr. For example, in many parts of United
States, the exposure rate from natural sources of radiation is between 5 and 15 jiR/hr. This
ambient level is referred to as the background exposure rate.

Many commercially available radiation detectors measure radiation fields in terms of |iR/hr or
counts per minute (cpm).  Counts per minute  refers to the number of radiation interaction events
of ionizing particles or photons that are detected, or counted, in a minute by the detector. Only a
fraction of those particles or photons that interact with the detector result in counts. The number
of counts per minute can be related to exposure rate or radiation dose for a known radionuclide
and established geometry for which the instrument has been calibrated.

Radiation dose is a measurement or estimate of the body's exposure to ionizing radiation. It is
typically measured in units of rem.  In the environment  and at POTWs, doses are often measured
in terms of millirem (mrem). A millirem is one one-thousandth (1/1,000) of a rem; a microrem
(jirem) is one-millionth (1/1,000,000) of a rem.  The dose rate is expressed in terms of dose per
unit time, again usually an hour, as millirem/hr.  For external radiation, exposure rates are often
equated to dose rates using the conversion of 1 |iR/hr = 1 |irem/hr.  Doses from internal exposure
to radioactive material that has been ingested or inhaled are more difficult to determine.
Computer models that account for the distribution and excretion of the radioactive material
within the body are used for estimating doses and dose rates from internal radioactive
contamination.

What Are the Effects of Radiation Exposure?

Radiation may cause a range of effects  when it interacts in, or passes through, living tissue.
Human health effects begin at the cellular level.  Some cells are unaffected by the radiation while
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others may be damaged but survive and reproduce normally.  However, some damaged cells may
survive in a modified form, which could potentially result in cancer.  Some cells may die from
the exposure to radiation.

Other health effects occur to organs and the whole body. Effects from low doses of radiation
(tens of, rems) may include birth defects and genetic effects.  High doses of radiation (hundreds
of rems) over short periods of time may cause organ damage and, if high enough, death.  Doses
associated with exposures to natural background radiation or typical radioactive materials in
POTWs are thousands of times lower than the high doses that cause significant biological
damage.

At low doses, the principal concern associated with radiation  exposure is the  possible occurrence
of cancer years after the exposure occurs.  Other effects such  as birth defects  and genetic effects
are not likely.  For such low doses, the likelihood of producing cancer has not been directly
established because it is not possible to distinguish cancers produced by such low levels of
radiation from cancers that occur normally. The risk of developing cancer is usually expressed
in terms of probability of an adverse health effect because a given dose of radiation does not
produce a cancer in all cases.

What Can Be Done to Reduce Radiation Exposure Risks to Workers?

The following discussion applies only to systems where accumulation of radioactive material has
been demonstrated by radiological health surveys.

POTW workers are most likely to be exposed to elevated levels of radioactive materials when
coming into contact with sludge and process water; during maintenance of contaminated pumps
or piping; or while moving or transporting sewage sludge and ash for disposal.  Possible sources
of radiation include pumps and piping where mineral scales accumulate; flocculation and
sedimentation tanks where residual sludges accumulate; filters, pumping stations, and storage
tanks where scales and sludges accumulate; and facilities where contaminated water
accumulates.  Facilities that are enclosed present the potential for enhanced radiation inhalation
exposure, particularly from radon. Exposure to radiation can also occur at sewage sludge and
ash processing or handling areas at the system and off-site locations such as landfills where
residuals are shoveled, transported, or disposed of.

Table A.2 shows the three primary paths of radiation exposure at a system: inhalation, ingestion,
and direct exposure.
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 Table A.2    Primary Pathways of Radiation Exposure at POTWs
 Pathway
Concern
 Inhalation
Inhalation of alpha- or beta-emitting radioactive materials is a concern because
radioactive material taken into the body results in radiation doses to internal
organs and tissues (e.g., lining of the lungs). Workers could inhale radioactively
contaminated dust or water droplets while dealing with sewage sludge,
wastewater, or ash. Cleaning methods for tanks, piping, or holding facilities
such as air scour, or use of high pressure water sprays can increase suspension
of radioactively contaminated water, dusts, and particulates in respirable air,
thus increasing the potential hazard of inhalation or ingestion. Workers can
inhale radon and its progeny  in both wet and dry conditions.  Simple dust masks
may not provide adequate protection from exposures via this pathway, and
workers should limit time spent at land disposal sites to reduce inhalation of
contaminated dust.
 Ingestion
Ingestion, or the swallowing of alpha, beta, or gamma-emitting radioactive
materials, is a concern for the same reasons as inhalation exposure.  Workers
can ingest radioactive materials if they fail to observe good sanitary practices
including washing their hands before eating; failing to cover their noses and
mouths by wearing approved respiratory protection and swallowing
contaminated dusts and water droplets; or eating and drinking in areas
(including land disposal sites), where dusts or water droplets could settle on
food or drink.  Simple dust masks may not provide adequate protection from
exposures via this pathway.
 Direct
 Exposure
Radioactive materials that emit gamma radiation are of concern because the
gamma rays pose an external radiation exposure hazard.  Because gamma rays
can pass through common construction materials and most protective clothing,
the distance between the radioactive material and the person, as well as the time
spent in proximity to the material are factors in the amount of exposure the
person receives.  As gamma radiation travels through air, exposure can occur
near a source of radiation as well as through direct contact. Workers most likely
to be directly exposed are those who handle or work in the vicinity of sludge
tanks, piping, sewage sludge and ash piles, and contaminated water; work in
areas of elevated indoor radon; or participate in  the maintenance of the treatment
system or the replacement and transportation of contaminated piping or pumps.
The Occupational Safety and Health Administration (OSHA) has developed occupational
radiation standards (see 29CFR 1910.1096) that might apply whenever an operator becomes
aware of the presence of radiation at the facility.  Although these standards may not apply to
municipal wastewater treatment plant workers, these workers may be covered by their State
OSHA program, requiring that all controls, monitoring, record keeping, and training outlined in
the OSHA standards be met.
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Additional OSHA standards that may be applicable to wastewater systems include:

•  Requirements that personal protection equipment (or PPE, for the eyes, face, be provided,
   used, and maintained whenever processes or radiological hazards capable of causing injury
   through absorption, inhalation, or physical contact necessitate such equipment.  There are
   numerous other requirements related to the possession and use of PPE, including training for
   employees who would use the equipment. For more information, see 29 CFR 1910.132-136.

•  Requirements for practices and procedures to protect employees in general industry from the
   hazards of entry into permit-required confined spaces. For more information, see
   29 CFR 1910.146.

In addition to the OSHA requirements, systems should be encouraged to follow the safety
practices listed below.  These measures can reduce workers~risk of exposure to radioactivity and
radioactive particulates:

Safety Measures

v  Use an OSHA-approved respirator to avoid inhalation of biological pathogens and
   chemically toxic materials in residuals.  Simple dust masks may not provide adequate
   protection.

v  Limit time spent at land disposal sites to reduce inhalation of contaminated dust.

v  Ventilate all buildings, especially where waste with high concentrations of radionuclides are
   stored.

»  Take standard OSHA  measures to limit the potential ingestion of heavy metals and biological
   pathogens present in residual sludges, ashes, and at land disposal sites to help reduce possible
   ingestion exposure to  radioactive materials.

v  Use protective gloves  and frequently wash hands  (particularly before eating, smoking, and
   drinking) to reduce  the potential for ingestion. Similarly, avoid eating, smoking, and
   drinking in the vicinity of facilities or land disposal  sites where air suspension of
   contaminated particulates or water droplets could occur.

v  Locate treatment units and waste storage areas as far away from common areas (e.g., offices)
   as possible.

»  Shower after exposure to potentially radioactive materials and launder work clothing at the
   system if possible.  If  laundering equipment is not available, workers should keep and wash
   work clothing separately  and avoid wearing contaminated clothing into the home. Work
   boots or shoes should  be wiped and cleaned after  potential contamination.  They should  stay
   at the system or not be worn into the home.

»  Use gamma survey  instruments or equivalent monitors at least once annually to monitor the
   system's ambient radiation levels in areas where radionuclides are removed.
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»  Monitor levels of radiation to which staff are exposed. Systems should contact, or be
   referred to, State or other radiation experts for more information on how to monitor radiation
   levels.


Additional Safety Considerations

Radon is a natural decay product of radium and other radionuclides.  Section 6.1.4 describes
procedures for interpreting measured radon in air.

If the potential for elevated levels of radionuclides or radiation has been found at the POTW in
accordance with the procedures discussed in this recommendations report, having operators who
are trained in treating for radionuclides, and handling, disposing of, and transporting TENORM
waste, is highly recommended.  Assistance and advice are available from the appropriate State
Radiation Control Program (see Appendix E), the EPA Regional Radiation Programs (see
Appendix D), and the NRC Regional Offices (see Appendix C).
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APPENDIX B
NRC AND EPA REGIONAL OFFICES BY STATE AND
IDENTIFICATION OF NRC AGREEMENT STATES
                  NRC and EPA Regions
                                                             EPA
                                                           REGION 1
                               EPA  t-~\ "-
                             REG.OM7<.   V
    : ' Included in NRC Retpon II and EPA Reran 2 - Puerto RKO and U.S. Virgin Islands
     - Inlcuded in NRC Reran IV-AlaE*a and Hawaii
      Included in EPA Region 9 - Guam and American Samoa
Figure B.I   Delineation of the NRC and EPA Regions.
ISCORS Technical Report 2004-04
B-l
Final, February 2005

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                                                       NRC St»te% (15)
                                                       Agr**nvtnt St»t«t (33);j
                                                       NRC SUtM ttiat h«v* *X[K»t*d IntMl
                                                       lo ilgn Agn«m*iit (2) g
Figure B.2    Delineation of NRC Agreement States as of October 2004.
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Final, February 2005

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APPENDIX C
NRC REGIONAL OFFICES

 Table C.1    NRC Regional Offices
        Region and Address
  Division of Nuclear
   Materials Safety
   State Agreements
       Officer
 Region I
 475 Allendale Road
 King of Prussia, PA 19406-1415
(610)337-5000
(610)337-5042
(610)337-5358
 Region II
 Sam Nunn Atlanta Federal Center
 61 Forsyth St, SW
 Suite 23T85
 Atlanta, Ga 30303-8931
(404) 562-4400
See Region I
 Region III
 2443 Warrenville Road, Suite 210
 Lisle, IL 60532-4352
(630) 829-9500
(630) 829-9661
 Region IV
 Texas Health Resources Tower
 611 Ryan Plaza, Suite 400
 Arlington, TX 76011-4005
(817)860-8100
(817)860-8116
(817)860-8143
For further information, consult the NRC website at URL:
http://www.nrc.gov/who-we-are/locations.html
ISCORS Technical Report 2004-04
    C-l
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APPENDIX D
EPA REGIONAL OFFICES

 Table D.1   EPA Radiation Program Managers (As of 6/10/2004)
NAME/ADDRESS
William White (acting)
US EPA/Region 1
1 Congress Street Suite 1100
Boston, MA 02 11 4-2023
Paul A. Giardina
US EPA/Region 2
290 Broadway, 28th Floor
New York, NY 10007-1866
Carol Febbo
US EPA/Region 3
1650 Arch Street
Philadelphia, PA 19103-2029
Todd Rinck
US EPA/Region 4
61 Forsyth Street, SW
Atlanta, GA 3 03 03 -3 104
Jack Barnette
US EPA/Region 5 (AE-17J)
77 West Jackson Boulevard
Chicago, IL 60604
Monica Smith
US EPA/Region 6 (6PD-T)
1445 Ross Avenue
Dallas, Texas 75202-2733
Robert Dye
US EPA/Region 7 (ARTD/RALI)
901 North 5th Street
Kansas City, KS 66101
Richard Graham
US EPA/Region 8 (8P-AR)
999 18th Street, Suite 500
Denver, CO 80202-2466
PHONE NO.
(617)918-1532
(212) 637-4010
(215) 814-2076
(404) 562-9062
(312)886-6175
(214) 665-6780
(913)551-7605
(303)312-7080
FAX NO.
(617)918-1333
(212) 637-4942
(215)814-2101
(404) 562-9095
(312)886-0617
(214) 665-6762
(913)551-7065
(303)312-6044
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 Table D.1    EPA Radiation Program Managers (As of 6/10/2004) (continued)
NAME/ADDRESS
Michael S. Bandrowski
US EPA/Region 9 (Air-6)
75 Hawthorne Street
San Francisco, CA 94 105
Jeff Kenknight
US EPA/Region 10
1200 Sixth Avenue 10th Floor
Seattle, WA 98 101
PHONE NO.
(415)947-4194
(206) 553-6641
FAX NO.
(415)744-1073
(206)553-0110
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APPENDIX E
STATE AGENCIES FOR RADIATION CONTROL (AS OF
OCTOBER 1,2004)

For an up to date listing of the State radiation control contacts given below, see the Conference
of Radiation Control Program Directors (CRCPD) Web site at URL: http://www.crcpd.org/ or
Director of Agreement State and Non-Agreement State Directors and State Liaison Officers at
the Office of State and Tribal Programs, USNRC, Web site:
http://www.hsrd.ornl.gov/nrc/asframe.htm.

For a current listing of State Radon Contacts, see the CRCPD Web site at
http://www.crcpd.org/radon.asp.
ALABAMA (Agreement State)
Kirksey E. Whatley, Director
State Department of Public Health
Office of Radiation Control
201 Monroe Street, P.O. Box 303017
Montgomery, AL 36130-3017
Phone: 334/206-5391
Fax:  334/206-5387
kwhatley@adph.state.al.us
http://www.adph.org/
 ALASKA
 Clyde E. Pearce, Chief
 Section of Laboratories/State of
 Alaska/DH&SS
 Radiological Health Program
 4500 Boniface Parkway
 Anchorage, AK  99507-1270
 Phone: 907/334-2107
 Fax:  907/334-2163
 clyde_pearce@health. state, ak.us
 http://www.hss.state.ak.us/dph/labs/
ARIZONA (Agreement State)
Aubrey V. Godwin, Director
Arizona Radiation Regulatory Agency
4814 South 40th Street
Phoenix, AZ  85040
Phone: 602/255-4845 ext. 222
Fax:   602/437-0705
agodwin@arra. state, az.us
http://www.arra. state, az.us/
 ARKANSAS (Agreement State)
 Tared Thompson, Program Leader
 Division of Radiation Control & Emergency
 Management
 Department of Health
 4815 West Markham Street, Slot #30
 Little Rock, AR 72205-3867
 Phone: 501/661-2173
 Fax:   501/661-5387
 jwthompson@healthyarkansas.com	
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CALIFORNIA (Agreement State)
Edgar D. Bailey, CHP, Chief
Division of Food & Radiation Safety
Radiological Health Branch
California Department of Health Services
P.O. Box 997414
Sacramento, CA 95899-7414
Phone: 916/440-7899
Fax:   916/440-7900
ebailey@dhs.ca.gov/rhb/
http://www.dhs.cahwnet.gov/rhb/index.htm
 COLORADO (Agreement State)
 Steve Tarlton, P.E., Unit Leader
 Radiation Management Program
 Hazardous Materials and Waste Management
 Division
 Dept. of Public Health and Environment
 4300 Cherry Creek Drive South
 Denver, CO 80230-1530
 Phone: 303/692-3428
 Fax:   303/759-5355
 steve.tarlton@state.co.us
 http ://www.cdphe. state, co.us/hm/rad/radiatio
 nservices.asp	
CONNECTICUT
Edward Wilds, Ph.D., Director
Division of Radiation
Department of Environmental Protection
79 Elm Street
Hartford, CT  06106-5127
Phone: 860/424-3029
Fax:   860/424-4065
edward.wilds@po. state, ct.us	
 DELAWARE
 Frieda Fisher-Tyler, Administrator
 Office of Radiation Control
 Delaware Division of Public Health
 P.O. Box 637
 Dover, DE 19903
 Phone: 302/744-4944
 Fax:   302/739-3839
 frieda.fisher-tyler@ state, de.us	
DISTRICT OF COLUMBIA
Harold Monroe, Bureau Chief
Department of Health
Bureau of Food, Drug, and Radiation
Protection
51 N Street NE, Room 6025
Washington, DC 20002
Phone: 202/535-2188
Fax:   202/535-1359
hmonroe@dchealth.com
 FLORIDA (Agreement State)
 William A. Passetti, Chief
 Bureau of Radiation Control
 Florida Department of Health
 4052 Bald Cypress Way, Bin C21
 Tallahassee, FL 32399-1741
 Phone: 850/245-4266
 Fax:   850/487-0435
 bill_passetti@doh.state.fl.us
 http://www.doh.state.fl.us/environment/radiat
 ion
GEORGIA (Agreement State)
Cynthia Sanders
Radioactive Materials Program
Department of Natural Resources
4244 International Parkway, Suite 114
Atlanta, GA 30354
Phone: 404/362-2675
Fax:   404/362-2653
csanders@dnr.state.ga.us
http://www.dnr. state.ga.us/environ/aboutepd_
files/rmprogram/default.htm	
 HAWAII
 Russell S. Takata, Program Manager
 Noise, Radiation, and Indoor Air Quality
 Branch
 Department of Health
 591 Ala Moana Boulevard
 Honolulu, HI 96813-4921
 Phone: 808/586-4700
 Fax:   808/586-5838
 rtakata(S)ehsdmail.health, state.hi.us
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IDAHO
Douglas Walker, Senior Health Physicist
Development of Environmental Quality
INEEL Oversight and Radiation Control
Program
900 N. Skyline, Suite C
Idaho Falls, ID 83402-1718
Phone: 208/528-2617
Fax:   208/528-2605
dwalker@deq. state.id.us	
 ILLINOIS (Agreement State)
 Gary N. Wright, Director
 Division of Nuclear Safety
 Illinois Emergency Management Agency
 1035 Outer Park Drive, 5th Floor
 Springfield, IL  62704
 Phone: 217/785-9868
 Fax:   217/524-4724
 wright@iema.state.il.us
 http ://www. state.il .us/idns	
INDIANA
John H. Ruyack, Director
Indoor and Radiologic Health Division
State Department of Health
2 North Meridian Street, 5F
Indianapolis, IN 46204-3003
Phone: 317/233-7146
Fax:   317/233-7154
jruyack@isdh. state.in.us
http://www.in.gov/isdh/regsvcs/index.htm
 IOWA (Agreement State)
 Donald A. Flater, Chief
 Iowa Department of Public Health
 Bureau of Radiological Health
 401 S.W. 7th Street, Suite D
 Des Moines, IA  50309
 Phone: 515/281-3478
 Fax:   515/725-0318
 dflater@idph. state.ia.us
 http://www.idph.state.ia.us/pa.rh.htm
KANSAS (Agreement State)
Thomas A. Conley, CHP, RRPT, Chief,
Radiation and Asbestos Control Section
Bureau of Air and Radiation
Department of Health and Environment
1000 SW Jackson Street, Suite 310
Topeka, KS 66612-1366
Phone: 785/296-1565
Fax:   785/296-0984
tconley@kdhe.state.ks.us
http://www.kdh.state.ks.us/bar/	
 KENTUCKY (Agreement State)
 Robert L. Johnson, Manager
 Radiation Health and Toxic Agents Branch
 Cabinet for Health Services
 275 East Main Street,
 Mail Stop HS-2E-D
 Frankfort, KY 40621-0001
 Phone: 502/564-7818 Ext. 3697
 Fax:   502/564-6533
 robertL.johnson@mail.state.ky.us
LOUISIANA (Agreement State)
Michael E, Henry, Senior Environmental
Scientist
Permits Division
Office of Environmental Services
602 N. 5th, P.O. Box 4313
Baton Rouge, LA 70821-4313
Phone: 225/219-3366
Fax:   225/219-3154
,ichael.henry@la.gov
http://www.deq.state.la.us/	
 MAINE (Agreement State)
 Jay Hyland, PE, Program Manager
 Radiation Control Program
 Division of Health Engineering
 11 State House Station
 Augusta, ME 04333
 Phone: 207/287-5677
 Fax:   207/287-3059
 jay.hyland@maine.gov
 http://www.maine.gov/dhs/eng/rad/index.html
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MARYLAND (Agreement State)
Roland G. Fletcher, Environmental Program
Manager III
Radiological Health Program
Air and Radiation Management
Administration
Maryland Department of Environment
1800 Washington Boulevard, Suite 750
Baltimore, MD 21230-1724
Phone: 410/537-3300
Fax:  410/537-3198
rflecther@mde.state.md.us	
 MASSACHUSETTS (Agreement State)
 Robert Walker, Director
 Radiation Control Program
 Department of Public Health
 90 Washington St.
 Dorchester, MA  02121
 Phone: 617/427-2944
 Fax:   671/427-2925
 bob.walker@state.ma.us
 http://www.mass.gov/dph/rcp/
MICHIGAN
Liane Shekter Smith, Chief
Hazardous Waste and Radiological Protection
Section
Waste and Hazardous Materials Division
Michigan Department of Environmental
Quality
525 W. Allegan Street
P.O. Box 30241
Lansing, MI 48909-7741
Phone: 517/373-0530
Fax:  517/373-4797
shekterl @mi chigan. gov
http://www.michigan.gOv/deq/0,1607-7,7-
135-3312-4120—,00.htm
 MINNESOTA (Prospective Agreement
 State)
 Linda Bruemmer, Manager
 Section of Asbestos, Indoor Air, Lead, &
 Radiation
 Department of Environmental Health
 121 E. Seventh Place, Suite 220
 P.O. Box 64975
 St. Paul, MN 55164-0975
 Phone: 651/215-0945
 Fax:   651/215-0975
 linda.bruemmer@health.state.mn.us
 http://www.health.state.mn.us/
MISSISSIPPI (Agreement State)
Robert W. Goff, Director
Division of Radiological Health
State Department of Health
3150 Lawson Street
Jackson, MS 39215-1700
Phone: 601/987-6893
Fax:  601/987-6887
rgoff@msdh. state.ms.us
http://www.health.ms.gov	
 MISSOURI
 Keith Henke, Planner
 Department of Health and Senior Services
 Section for Environmental Public Health
 930 Wildwood Dr.
 P.O. Box 570
 Jefferson City, MO 65102-0570
 Phone: 573/751-6112
 Fax:   573/526-6946
 henkek@dhss.state.mo.us	
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MONTANA
Juan Stevens, Coordinator
Radiological Health Program
Montana Department of Public Health &
Human Services
Licensure Bureau
2401 Colonial Drive
P.O. Box 202953
Helena, MT 59620-2953
Phone: 406/444-1510
Fax:   406/444-3456
justevens@state.mt.us
 NEBRASKA (Agreement State)
 Julia A. Schmitt, Program Manager
 X-Ray/Radioactive Materials/Emergency
 Response
 Regulation and Licensure
 Department of Health & Human Services
 301 Centennial Mall South, P.O. Box 95007
 Lincoln, NE 68509-5007
 Phone: 402/471-0528
 Fax:   402/471-0169
 julia.schmitt@hhss. state.ne.us
 http://www.hhs.state.ne.us/rad/radindex.htm
NEVADA (Agreement State)
Stanley R. Marshall, Supervisor
Radiological Health Section
Bureau of Health Protection Services
Nevada State Health Division
1179 Fairview Drive, Suite 102
Carson City, NV 89701-5405
Phone: 775/687-5394, Ext. 276
Fax:   775/687-5751
smarshall@nvhd.state.nv.us
http://www.hhs.state.ne.us/rad/radindex.htm
 NEW HAMPSHIRE (Agreement State)
 Dennis O'Dowd, Acting Chief
 Radiological Health Section
 Bureau of Radiological Health
 Department of Health and Human Services
 29 Hazen Drive
 Concord, NH 03301-6504
 Phone: 603/271-4588
 Fax:   603/225-2325
 dodowd@dhhs.state.nh.us
NEW JERSEY
Jill Lipoti, Ph.D., Assistant Director
Radiation Protection Programs & Release
Prevention
Division of Environmental Safety, Health and
Analytical Programs
Department of Environmental Protection
P.O. Box 415
Trenton, NJ  08625-0415
Phone: 609/984-5636
Fax:   609/633-2210
jill.lipoti@dep.state.nj.us
http://www.state.nj.us/dep/rpp/index.htm
 NEW MEXICO (Agreement State)
 William Floyd, Program Manager
 Radiation Protection Program
 Department of Environment
 1190 St. Francis Drive, Room S2100
 P.O. Box 26110
 Santa Fe, NM 87505-4173
 Phone: 505/476-3236
 Fax:   505/476-3232
 william_floyd@nmenv. state.nm.us
 http://www.nmenv. state.nm.us/nmrcb/home.h
 tml
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NEW YORK (Agreement State)
Adela Salame-Alfie, Ph.D., Director
Bureau of Environmental Radiation
Protection
New York State Health Department
547 River Street
Troy, NY 12180-2216
Phone: 518/402-7550
Fax:   518/402-7554
asaO l@health. state.ny.us

Clayton J. Bradt, CHP, Principal
Radiophysicist, Radiological Health Unit
Division of Safety and Health
New York State Department of Labor
NYS Office Campus, Building 12, Room 169
Albany, NY 12240
Phone: 518/457-1202
Fax:   518/485-7406
usccjb@labor.state.ny.us

John P. Spath, Program Manager
Radioactive Waste Policy and Nuclear
Coordination
NYS Energy Research and Development
Authority
17 Columbia Circle
Albany, NY 12223-6399
Phone: 518/862-1090
Fax:   518/862-1091
jps@nyserda.org	
 Gene Miskin, Director
 Bureau of Radiological Health
 New York City Department of Health
 2 Lafayette Street, 11th Floor
 New York, NY 10007
 Phone: 212/676-1550
 Fax:   212/676-1548
 gmiskin@health.nyc.gov

 Barbara A. Youngblood, Chief
 Radiation Section
 Division of Solid & Hazardous Material
 NYS Depart, of Environmental Conservation
 625 Broadway, 8th Floor
 Albany, NY 12233-7255
 Phone: 518/402-8579
 Fax:   518/402-8646
 bay oungb@gw.dec. state.ny.us
 www.dec.state.ny.us/website/dshm/hazrad/ra
 d.htm
NORTH CAROLINA (Agreement State)
Beverly O. Hall, Chief
Division of Radiation Protection
Department of Environmental & Natural
Resources
3 825 Barrett Drive
Raleigh, NC 27609-7221
Phone: 919/571-4141
Fax:   919/571-4148
beverly.hall@ncmail.net
http://www.ncradiation.net	
 NORTH DAKOTA (Agreement State)
 Terry O'Clair, Director
 North Dakota Department of Health
 Division of Air Quality
 1200 Missouri Avenue, Room 304
 Bismark,ND 58506-5520
 Phone: 701/328-5188
 Fax:   701/328-5200
 toclair@state.nd.us
 http://www.health.state.nd.us/AQ/
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OHIO (Agreement State)
Robert Owen, Chief
Bureau of Radiation Protection
Ohio Department of Health
P.O.Box 118
Columbus, OH 43216-0118
Phone: 614/644-7860
Fax:   614/466-0381
rowen(S)ew.odh.state.oh.us
 OKLAHOMA (Agreement State)
 Mike Broderick, Environmental Program
 Administrator
 Radiation Management Section
 Department of Environmental Quality
 P.O. Box 1677
 Oklahoma City, OK 73101-1677
 Phone: 405/702-5155
 Fax:   401/702-5101
 mike.broderick@deqmail. state, ok.us
OREGON (Agreement State)
Terry D. Lindsey, Program Director
Radiation Protection Services
Oregon Health Services
Department of Human Services
800 NE Oregon Street, Suite 260
Portland, OR 97232-2162
Phone: 503/731-4014, Ext. 660
Fax:   503/731-4081
terry.d.lindsey@state.or.us
http://www.dhs.state.or.us/publichealth/rps/in
dex.cfm
 PENNSYLVANIA (Prospective Agreement
 State)
 David J. Allard, CHP, Director
 Bureau of Radiation Protection
 Department of Environmental Protection
 Rachel Carson State Office Building
 P.O. Box 8469
 Harrisburg, PA  17105-8469
 Phone: 717/787-2480
 Fax:   717/783-8965
 djallard@state.pa.us
 http://www.dep.state.pa.us/dep/deputate/airw
 aste/rp/rp.htm	
RHODE ISLAND (Agreement State)
Marie Stoeckel, Chief
Division of Occupational & Radiological
Health
Department of Health
3 Capitol Hill, Room 206
Providence, RI 02908-5097
Phone: 401/222-7755
Fax:   401/222-2456
maries@doh. state, ri.us
 SOUTH CAROLINA (Agreement State)
 T. Pearce O'Kelley, Chief
 Bureau of Radiological Health
 Department of Health & Environmental
 Control
 2600 Bull Street
 Columbia, SC 29201
 Phone: 803/545-4403
 Fax:   803/545-4412
 okelletp@dhec.sc.gov
 http ://www. scdhec.net/

 Henry Porter, Assistant Director
 Division of Waste Management
 Bureau of Land and Waste Management
 Department of Health and Environmental
 Control
 2600 Bull Street
 Columbia, SC 29201
 Phone: 803/896-4245
 Fax:   803/896-4242
 porterhj @dhec. state, sc.us	
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SOUTH DAKOTA
Robert Stahl, Medical Facilities Engineer Svr.
Office of Health Care Facilities
Licensure and Certification
Systems Development and Regulations
615 East 4th Street
Pierre, SD 57501-1700
Phone: 605/773-3356
Fax:   605/773-6667
bob.stahl@state.sd.us
TENNESSEE (Agreement State)
Lawrence E. Nanney, Director
Division of Radiological Health
L and C Annex, Third Floor
Department of Environmental Conservation
401 Church Street
Nashville, TN 37243-1532
Phone: 615/532-0364
Fax:   615/532-7938
Eddie.Nanney@state.tn.us
http://www.tennessee.gov/environment/rad/
TEXAS (Agreement State)
Richard A. Ratliff, PE, LMP, Chief
Bureau of Radiation Control
Texas Department of Health
1100 West 49th Street
Austin, TX 78756-3189
Phone: 512/834-6679
Fax:   512/834-6708
ri chard.ratliff@tdh. state.tx.us
http://www.tdh.state.tx.us/radiation/aboutbrc.
htm

Susan M. Jablonski, Technical Advisor
Office of Permitting, Remediation and
Registration, Resource Conservation
Texas Commission on Environmental Quality
P.O. Box 13087, Mail Code 122
Austin, TX 78711-3087
Phone: 512/239-6731
Fax:   512/239-6362
sj ablons@tceq. state.tx.us
http://www.tceq.state.tx.us	
UTAH (Agreement State)
Dane Finerfrock, Director
Division of Radiation Control
Department of Environmental Quality
168 North 1950 West
P.O. Box 144850
Salt Lake City, UT 84114-4850
Phone: 801/536-4264
Fax:   801/533-4097
dfmerfrock@utah.gov
http://www.radiationcontrol.utah.gov
VERMONT
Carla A. White, Radiological Health
Specialist
Office of Radiological Health
Department of Health
P.O. Box 70, Drawer #43
108 Cherry Street
Burlington, VT 05402-0070
Phone: 802/865-7743
Fax:   802/865-7745
cwhite@vdh. state.vt.us	
VIRGINIA
Leslie P. Foldesi, CHP, Director
Bureau of Radiological Health
Virginia Department of Health
109 Governor Street, Room 730
Richmond,  VA  23219
Phone: 804/786-5932
Fax:   804/786-6979
lfoldesi@vdh. state, va.us
http://www.vdh.state.va.us/rad/index.htm
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WASHINGTON (Agreement State)
Gary L.Robertson, Director
Division of Radiation Protection
Department of Health
7171 Cleanwater Lane, Bldg. #5
P.O. Box 47827
Olympia, WA 89504-7827
Phone: 360/236-3210
Fax:   360/236-2255
gary.robertson@doh.wa.gov
http://www.doh.wa.gov/ehp/rp	
 WEST VIRGINIA
 Dan Hill, Chief
 Radiological Health Program
 815 Quarrier Street, Suite 424
 Charleston, WV 25301-2616
 Phone: 304/558-6772
 Fax:   304/558-0524
 danhill@wvdhr.org
WISCONSIN (Agreement State)
Paul S. Schmidt, Chief
Radiation Protection Section
Division of Public Health
Department of Health and Family Services
P.O. Box 2659
Madison, WI 53701-2659
Phone: 608/267-4792
Fax:   608/267-4799
schmips@dhfs.state.wi.us
http://www.dhfs.state.wi.us/licensing.htm
 WYOMING
 David A. Finley, Administrator
 Solid and Hazardous Waste Division
 Department of Enviornmental Quality
 Herschler Building, 4W
 122 W. 25th Street
 Cheyenne, WY 82002
 Phone: 307/777-7753
 Fax:   307/777-5973
 dfinle@state.wy.us
PUERTO RICO
Mayra Toro, M.S., Director
Radiological Health Division
Department of Health
P.O. Box 70184
San Juan, PR 00936-8184
Phone: 787/274-7815
Fax:   787/274-6829
mtoro@salud.gov.pr	
 VIRGIN ISLANDS
 Roy E. Adams, Commissioner
 Department of Planning and Natural
 Resources
 179 Altona and Wilgounot-Charlotte Amalie
 St.  Thomas, VI 00802
 Phone: 340/774-3320
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APPENDIX F
EXAMPLES OF POTWS THAT HAVE RADIONUCLIDE
MATERIALS PROGRAMS

Albuquerque, New Mexico

The City of Albuquerque has drafted a Radioactive Discharge Monitoring Program (RDMP).
This will be a voluntary program of monitoring and reporting. The Albuquerque POTW has
found they have the responsibility to be aware of all discharges to the sewer system that could
impact operations at the treatment plant or impact the health and safety of employees and the
public. The POTW will implement a program of discharger registration that requires dischargers
to (1)  periodically report their radionuclide discharges, (2) allow the POTW to perform
surveillance monitoring, and (3) commit to voluntarily limit their discharges to levels that are as
low as reasonably achievable (ALARA).  These registrations will be issued and monitoring of
the discharges will be permitted in accordance with a city sewer use and wastewater control
ordinance. The agreement could be in the form of an amendment to an existing sewer discharge
permit.

The Albuquerque POTW obtained a list of licensed radioactive materials users in the municipal
service area from the appropriate regulatory authority (New Mexico is an Agreement State).
Each of the licensees was evaluated to determine whether or not they discharge or have the
potential to discharge radioactive materials to the sewer. This included an initial walk-through to
familiarize the RDMP staff with the nature of the operation and potential opportunities for waste
minimization.

The POTW will negotiate discharge limits with the dischargers so that the aggregate regulated
discharges from all licensed facilities is ALARA and produces no greater than 1 in 10,000 excess
risk of fatal cancer to the hypothetical most exposed individual.  The POTW will work with
potential dischargers to prevent accidental releases of radioactive materials.

The Albuquerque POTW retains a certified Health Physicist to interpret the  reports from the
dischargers and from monitoring the dischargers and the treatment facility.  The health physicist
uses radiation exposure models to ensure the radiation dose to the critical group is ALARA.

The dischargers will be asked  to provide annual reports regarding the discharges they have made
or plan to make to the sewer.  In addition, the RDMP staff collects samples from the facilities'
sample locations on a regularly scheduled basis and/or unannounced. The samples are analyzed
by the State.  To date the radionuclides found in the sewage have been of medical origin.
Gamma radiation detectors installed in the plant have indicated that no measurable radiation
exposure is being received by  plant workers.

Formal adoption of the RDMP plan awaits passage of a revised sewer use and wastewater
control ordinance. It has been stalled for more than 2 years due to its "political sensitivity."
Unless there is  a demand by dischargers for the change to occur, the situation will remain "as is."
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St. Louis, Missouri

The City of St.  Louis has its own requirements to limit radioactive discharges from industrial
users. The district is concerned that low-level radioactive materials being discharged to the
sewer system by numerous small sources may be concentrated by the district's wastewater
treatment processes and possibly pose a hazard for the employees and adversely affect the
district's sludge disposal options.

The District Ordinance for sewer use contains a limit of 1 curie/yr for the aggregate discharge
from all users in a watershed (except excreta from individuals undergoing medical treatment or
diagnosis). This number is currently under review.

The district requested lists of licensees from the NRC and the State and wrote the licensees
letters informing them of the limits for radionuclide dischargers. Licensees are required to write
the sewer district requesting approval to  discharge radioactive materials and indicating the
isotopes and the amounts to be discharged  annually.  The district then approves the discharges.
The district requires quarterly reports from the licensees to ensure compliance with the District
Ordinance and State and Federal regulations.  The licensee's discharge permit is then modified to
incorporate the approval of discharges and the reporting requirements.

As alternatives to discharging to the sewer system, licensees are encouraged to consider shipping
the waste to an approved low-level radioactive waste disposal site or storing the waste for at least
ten half-lives to allow sufficient decay to background levels prior to disposal to the sewer.

Oak Ridge, Tennessee

In response to its sewage sludge contamination problems (see Section 1.2),  Oak Ridge developed
a site-specific, risk-based methodology for establishing radionuclide limits for its sewage sludge.
The sewage sludge criteria were then used  to determine allowable plant releases that provided a
basis for setting facility specific discharge  criteria through the city's existing pretreatment
program. Additionally, the city included a "radioactive materials" section in its pretreatment
questionnaire which is filled out by all industrial users. The city also established an inexpensive
screening program designed to ensure that  elevated levels of radionuclides from spills or illegal
discharges, would not reach the land application site.

The city of Oak Ridge was strongly supported by Tennessee's State radiation control program.
Also aiding in the success of the program was ORWTP's close working relationship with local
industry. The city of Oak Ridge expended considerable effort in developing a program that
controlled radionuclide discharges in a manner that minimized regulatory burdens on local
industry and still provided adequate protection for the POTW.
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APPENDIX G
GLOSSARY AND ACRONYMS

AEA. Atomic Energy Act

Agreement State. Any State with which the Nuclear Regulatory Commission, or Atomic Energy
Commission, has entered into an effective agreement under section 274b of the Atomic Energy
Act, as amended.  Under the agreement, the Commission relinquishes certain regulatory
authority to the State which the State assumes under its own authority-the use of reactor-
produced isotopes, the source materials uranium and thorium, small (non-critical) quantities of
special nuclear materials, uranium mill tailing, the disposal of low-level radioactive waste, and
the evaluation of sealed sources and devices.  Currently, there are 33 Agreement States.

Background Radiation. Radiation from cosmic sources, naturally occurring radioactive
material (NORM), including radon (except as a decay product of source or special nuclear
material)., and global fallout as  it exists in the environment from the testing of nuclear explosive
devices or from nuclear accidents like Chernobyl which contribute to background radiation and
are not under the control of the  cognizant organization. Background radiation does not include
radiation from source, byproduct, or special nuclear materials regulated by the cognizant
Federal or State agency.

Becquerel (Bq)  The International System (SI) unit of activity equal to one nuclear
transformation (disintegration)  per second.  1  (Bq) = 2.7 x 10"11  curies (Ci) = 27.03 picocuries.

Byproduct Material. In general, any radioactive material (except special nuclear material)
yielded in or made radioactive by exposure to the radiation incident to the process of producing
or utilizing special nuclear material.

Contamination. The presence  of elevated levels of radiation where you don't want it.

CPM.  counts per minute

Curie. The traditional unit of radioactivity. One curie (Ci) is equal to  37 billion atomic
disintegrations per second (3.7 x 1010 dps = 3.7 x 1010 Bq), which is approximately equal to the
decay rate of one gram of 226Ra. Fractions of a curie,  e.g., picocurie (pCi) or 10"12Ci and
microcurie (uCi) or 10"6 Ci, are levels typically encountered in the environment.

microcurie (jiCi).  one one-millionth (1/1,000,000) of a curie

picocurie (pCi). one one-trillionth (1/1,000,000,000,000) of a curie

Elevated Levels of Radioactive Material. Levels of radioactive material in sewage sludge or ash
that should alert a POTW that some appropriate action(s) may be warranted (see Chapter 6 of
this report).
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Exposure Rate.  The amount of ionization produced per minute in air by X-rays or gamma rays.
The unit of exposure rate is roentgens/hour (R/h); typical units are microroentgens per hour
(uR/h), i.e., 10'6R/h.

Gamma Radiation. Penetrating high-energy, short-wavelength electromagnetic radiation
(similar to X-rays) emitted during radioactive decay. Gamma rays are very penetrating and
require dense materials (such as lead or steel) for shielding.

HP Health Physicist

ISCORS  The Interagency  Steering Committee on Radiation Standards.

NARM. Naturally occurring or accelerator-produced radioactive material, such as radium, and
not classified as source material.

Naturally Occurring Radionuclides.  Radionuclides and their associated progeny produced
during the formation of the  earth or by interactions of terrestrial matter with cosmic rays.

NORM Naturally-occurring radioactive materials.

Radioactivity (or activity).  The mean number of nuclear transformations occurring  in a given
quantity of radioactive material per unit of time.  The International  System (SI) unit of
radioactivity is the becquerel (Bq).  The customary unit is the curie (Ci).

Radioactive Half Life. The time required for one-half of the atoms of a particular radionuclide
present to disintegrate.

Radioactive Decay. The spontaneous transformation of an unstable atom into one or more
different nuclides accompanied by either the emission of energy and/or particles from the
nucleus, nuclear capture or ejection of orbital electrons, or fission.  Unstable atoms  decay into a
more stable state, eventually reaching a form that does not decay further or has a very long
radioactive half-life.

Radionuclide. An unstable nuclide that undergoes radioactive decay.

Reconcentration.  The increase in the concentration of radioactive materials in sewage sludge or
ash resulting from wastewater and sludge treatment within the POTW.

rent (radiation equivalent man). The  conventional measurement unit of radiation dose for
estimating the body's effects from exposure to ionizing radiation. The corresponding
International System (SI) unit is the sievert (Sv):  1 Sv =  100 rem.

millirem.  one one-thousandth (1/1,000) of a rem.

microrem. one one-millionth (1/1,000,000) of a rem.

Roentgen (R)  intensity of photon (gamma or X-ray) radiation.

microroentgen (uR).  one one-millionth (1/1,000,000) of a roentgen.

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Source Material. In general, uranium and/or thorium other than that classified as special
nuclear material.

Special Nuclear Material. In general, plutonium, 233U, and uranium enriched in 235U; material
capable of undergoing a fission reaction.

TENORM Naturally occurring radioactive materials whose concentrations or exposures to
humans and the environment are increased by or as a result of past or present human practices.
TENORM does not include background radiation or the natural radioactivity of undisturbed
rocks or soils.  TENORM also does not include uranium or thorium in source material as defined
in the AEA and NRC regulations.
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APPENDIX H
SOURCES OF ADDITIONAL INFORMATION

ASTM E 181-82 (Reapproved 1991), "Standard General Methods for Detector Calibration and
Analysis of Radionuclides."American Society for Testing and Materials, Philadelphia,
Pennsylvania 19103.

CRCPD Publication 03-1, "Directory of Personnel Responsible for Radiological Health
Programs," January 2003, Conference of Radiation Control Program Directors, Inc., Frankfort,
Kentucky 40601, http://www.crcpd.org.

Miller, W.H., et al, 1996, "The Determination of Radioisotope Levels in Municipal Sewage
Sludge," Health Physics, v. 71, no. 3, p. 286.

Miller, M.L., Bowman, C.R., and M.G. Garcia, 1997, "Avoiding Potential Problems."

NCRP Report No. 50, "Environmental Radiation Monitoring," 1976, National Council on
Radiation Protection and Measurements, Bethesda, Maryland.

NCRP Report No. 58, "A Handbook of Radioactivity Measurement Procedures," 1985, National
Council on Radiation Protection and Measurements,  Bethesda, Maryland.
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APPENDIX I
ADDITIONAL  INFORMATION ON  NRC AND AGREEMENT
STATE LICENSING AND  ENFORCEMENT

This appendix provides additional information about how NRC and Agreement States License
users of radioactive materials, and how the agencies enforce the regulations.

Who Must Obtain a License and What Happens if this is not Done?

According to NRC's  10 CFR Part 30, Section 30.3:

      Except for persons exempt as provided in this part and Part 150 of this
      chapter, no person shall manufacture, produce, transfer, receive, acquire,
      own, possess, or use byproduct material except as authorized in a specific
      or general license issued pursuant to regulations in this chapter.

This means that, with a few specified exceptions, any activity involving byproduct material must
be conducted under a license issued by the NRC or an Agreement State.  The exempt activities
are described in NRC's 10 CFR Part 30. Most exemptions from specific licensing are for
consumer products, such as smoke detectors.

Persons who are required to obtain an NRC license but fail to do so would be in violation of
Federal law and, when discovered, would be subject to the penalties appropriate for such
violations. In any case, such persons would most likely be unable to obtain the byproduct
materials they need, because suppliers of such materials generally require copies of the license
authorizing possession and use of the materials before the materials are delivered to the user.

What Radioactive  Materials are Exempt from Licensing?

Section 30.3 cited above mentions certain exemptions from the NRC licensing requirements.
These exemptions include certain DOE activities and also users of articles containing byproduct
materials in concentrations and quantities below specified levels.  These articles include some
instruments containing luminous dials, such as timepieces, balances, marine compasses, electron
tubes, gas or smoke detectors, and some other products.  It should be noted that the
manufacturers and distributors of these exempt devices are subject to NRC licensing.

In addition to the above, some radioactive materials may be exempt from licensing because they
fall below NRC-established concentration or quantity levels.  These levels do not apply to
materials that have already been licensed but have for some reason, such as decay, diminished to
activities below these levels. The exemption applies only to the initial determination of whether
or not a potential user or owner  of byproduct material needs to be licensed or is exempt from
such a requirement. Once licensed, byproduct material remains under the conditions of the
license regardless of how small the activities become because of decay or any kind of
partitioning of the original licensed quantity.
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Why are Some Industrial and Medical Facilities not Licensed?

The NRC may not license some facilities that use radioactive materials if the material they use is
not byproduct material. Examples of such facilities would be those that use accelerators or
accelerator-produced radioactive materials. However, even though such facilities may not come
under NRC's jurisdiction, and are therefore not licensed by the NRC, they are usually within the
jurisdiction of a State and may be licensed by that State if their activity requires licensing.
Exceptions to this may be certain Federal facilities and their prime contractors, such as DOE
facilities which, although not licensed by NRC or the States, are regulated by internal DOE
Orders.

What Monitoring/Oversight Do NRC  and the Agreement States Provide for
Licensees under Their Control?

Both NRC and Agreement States monitor their licensees by means of periodic inspections.  The
frequency of inspections depends on the type of license issued to the licensee, and will vary from
annual inspections for the larger licensees, such as hospitals, radiopharmaceutical companies,
and other large users of byproduct materials, to inspections once every 3-5 years for small
licensees who may use only one small radioactive source in a routine and well-established
application.  The inspections are designed to review the licensee's operation to make sure that it
is being conducted safely and in accordance with good practices and the conditions specified on
the license. Inspection frequencies may be increased if the NRC  or Agreement State believes
that the licensee requires closer oversight to implement improvements in their program to raise
its standards. In addition, the license may be suspended or revoked if NRC or the Agreement
State finds that the licensee's operation does not meet minimum safety standards.

Some facilities may be under the jurisdiction of more than one entity, such as many medical
facilities that are licensed by NRC for those parts of their operation that use byproduct materials,
and by the State in which they operate for those parts that use accelerator-produced radioactive
materials. Most States regulate naturally-occurring and accelerator-produced radioactive
materials.

What Causes Discharges Outside of Regulations or License Conditions?

The probable causes of illegal discharges are poor licensee programs, lack of knowledge of the
regulations, or deliberate violations.  Discharges to the sanitary sewers by NRC or Agreement
State licensees must comply with NRC or compatible Agreement State regulations governing
this aspect of the licensee's operation. There are many mechanisms in place to provide
reasonable assurance that licensees will comply with this regulatory requirement. Licenses are
issued to licensees only after NRC or the Agreement State is satisfied that the licensee has  the
qualified staff, equipment,  procedures, instrumentation, training programs, and management
oversight deemed necessary to operate the proposed program in a safe manner and within the
restrictions specified in the license. Any signs of program weaknesses or irregular activities
identified during inspection are brought to the licensee's attention for corrective action, and if
these are found to be sufficiently serious, the license may be suspended pending completion of
corrective actions, or revoked, thereby ending the licensee's use of licensed materials.
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All these measures cannot prevent illegal discharges to the sewers, but they help to minimize
such a possibility, and they provide an opportunity to identify such illegal activities if they
occurred.

What Enforcement Actions do NRC and Agreement States take when Licensees
Discharge Outside Regulations or License Conditions?

The enforcement actions that could be taken in such cases depend on the specifics of the
situation. If the discharge above the limits is found to have been a one-time, inadvertent error in
an otherwise sound program, the licensee could be issued a violation and the licensee's
management may be called to the NRC or State offices for a meeting with NRC or State
management to discuss the incident and the corrective actions the licensee intends to take to
prevent recurrence. The NRC or State may also issue a letter to the licensee summarizing the
corrective actions to be taken and the completion schedule.  Follow-up inspections might be used
to confirm completion of the corrective actions and their adequacy. The NRC and some States
could also impose monetary penalties.

If, on the other hand, the discharge above the limits is found to be the result of a generally poor
program, additional and more escalated enforcement actions could be taken to change the
licensee's program. Such  changes may involve hiring more competent professionals or
managers, retraining of personnel, rewriting operating procedures, and any other measures that
may be needed to improve the quality of the program. The program is then monitored closely.
In more serious cases, the  license could be revoked.  In situations where willfulness is found and
the matter is under NRC jurisdiction, the matter could be referred to the Department of Justice
for appropriate legal action. If the matter is under State jurisdiction, it could be referred to the
State Attorney General.
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APPENDIX J
RADIOLOGICAL ANALYSIS LABORATORIES

There are a number of radiological laboratories throughout the United States that provide
analyses of sewage sludge samples for POTWs.  The Conference of Radiation Control Program
Directors (CRCPD) maintains a list of such laboratories. These laboratories provide radiological
analysis of diverse materials, have quality assurance and quality control programs, and will
perform work for both government and private firms. The list is available from the CRCPD by
phone at 502/227-4543, and is posted to the CRCPD web page, at URL: http://www.CRCPD.org
(go to the "Free Documents" tab, then to "Orphan Source Documents," and then to "Radioassay
and TCLP Services"). The list is updated periodically by the CRCPD. The CRCPD does not
guarantee that the list is comprehensive, nor is there any certification of the quality of services
provided.  Thus, the authors of this report provide reference to this list only as a convenience to
POTWs in locating laboratories that they may wish to evaluate. The NRC, EPA, and the
ISCORS Subcommittee do not certify, approve, or endorse these laboratories.

Following are suggested criteria that POTW operators can use to help evaluate radiological
laboratories:

1.  Does the laboratory possess the appropriate well-documented procedures, instrumentation,
   and trained personnel to perform the necessary analyses?
2.  Is the laboratory experienced in performing the same or similar analyses?
3.  Does the laboratory have satisfactory performance evaluation results from formal monitoring
   or accreditation programs?  The laboratory should have a formal quality assurance (QA)
   program in place. The laboratory should be able to provide a summary of QA audits and
   proof of participation in inter-laboratory cross-check programs. Equipment calibrations
   should be performed using National Institute of Standards and Technology (NIST) traceable
   reference radionuclide standards whenever possible.
4.  Is there an adequate capacity to perform all analyses within the  desired time frame?
5.  Does the laboratory provide an internal quality control review of all generated data that is
   independent of the data generators?
6.  Are there adequate protocols for method performance documentation and sample security?
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APPENDIX K
POTW RADON SITE-SPECIFIC SCREENING CALCULATION
Screening Calculation D: POTW Site-Specific Radon Concentration Estimates
Purpose: To estimate radon concentrations from Ra-226 and Th-228 for POTW Workers in a
loading or storage room, given certain room characteristics.
Calculation Procedure:
Obtain the following site-specific parameters:
      Sludge concentrations of Ra-226 and Th-228.
      Froom, the volume of the room in cubic meters.
      //room, the height of the room in meters.
      Aiudge, the bulk density of the sludge in grams per cubic centimeter.
      ^sludge, the volume of sludge in the room.
      ^sludge, the area which the sludge covers in the room.
      Rx, the room air exchange rate in exchanges per hour.
For the concentration of Rn-222 from Ra-226, use the following formulae:
Concentration in pCi/liter =
      (Sludge Concentration of Ra-226 in pCi/g) x 1.49 x (0.008 + Rx)'1 Aiudge Fsiudge / Froom
Concentration in WL =
      (Sludge Concentration of Ra-226 in pCi/g) x
      0.00931 x (0.008 + Rx) ~l x (2.69 /7room °'13 + Rx) ~l Aiudge Fsludge / Froom
For the concentration of Rn-220 from Th-228, use the following formulae:
Concentration in pCi/liter =
      (Sludge Concentration of Th-228 in pCi/g) x 720 x (45 + Rx) ~l Aiudge ^sludge / Vroom
Concentration in WL =
      (Sludge Concentration of Th-228 in pCi/g) x
      3.00 x (45 + Rx) -1 x (1.25 /7room °'77 + Rx) ^ Aiudge kludge / Froom
Compare concentrations (combined for WL, separate for pCi/liter) with the levels recommended
in Chapter 6.
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Note:

Increasing the room parameters Froom or Rx will lead to lower concentrations, as will decreasing
•Dsiudge, Fsiudge, ory4siudge. Similarly, decreasing the room parameters Fro0m or Rx will lead to
higher concentrations, as will increasing Aiudge, Fsiudge, ory4siudge.
EXAMPLE CALCULATIONS FOR ESTIMATING RADIATION
       EXPOSURE FROM RADIOANALYSIS OF SLUDGE SAMPLES

The following are example calculations based on the screening calculations described in
Chapter 6. Although these examples are based on real sludge measurements, most have been
chosen to illustrate atypical levels of radioactivity.

Example 1 :   POTW Radiation Exposure  Estimates for a High NORM
                Sludge

Screening Calculation A:

In Sample 1, the levels of 1-131 (6.2), Ra-226 (25), Ra-228 (38), and Th-228 (9) exceed the
"POTW Screening Concentration" in column 3 of Table 6.2.

Using the DSRs in Table 6.2, the non-radon doses from 1-131 (1.1), Ra-226 (24.3), Ra-228
(19.7), and Th-228 (8.2) add up to 53.3 mrem/year.

The estimated radon concentrations due to Ra-226 are 0.06 WL or 37 pCi/Liter of Rn-222. The
radon concentrations due to Th-228 are 0.43 WL or 220 pCi/Liter of Rn-220.  The total Working
Levels is 0.49 WL.

These results may warrant additional investigation, such as through a professional health
physicist or consultant. For the radon concentrations, radon monitoring could be performed, or
additional estimates  could be calculated using Screening Calculation D.

Screening Calculation D:

The concentration of Ra-226 is 25 pCi/g, and Th-228 is 9 pCi/g. The POTW room parameters
are Froom = 70,000 m3, hroom = 4 m, Aiudge = 1.5 g/cm3, Fsiudge = 15,000 m3, ^siudge = 7500 m2,
Rx = 2 per hour.

The concentration of Rn-222 from Ra-226 is

       25 x 1.49 / 2.008  x 1.5 x 15,000 / 70,000 = 6.0 pCi/liter
       25 x 0.00931 / 2.008  / (2.25 + 2) x 1.5 x 15,000 / 70,000 = 0.009 WL
The concentration of Rn-220 from Th-228 is

       9 x 720 / 47 x 1.5 x 7,500 / 70,000 = 22 pCi/liter
       9 x 3.00 / 47 / (0.4 + 2) x 1.5 x 7,500 / 70,000 = 0.038 WL

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These concentrations may warrant additional investigation, such as through radon monitoring
and/or a professional health physicist or consultant.

Example 2:    POTW Radiation Exposure Estimates for a High
                 Medical-Isotope Sludge

Screening Calculation A:

In Sample 2, the levels of 1-131 (230 pCi/g), K-40 (13 pCi/g), Ra-226 (2 pCi/g), Ra-228
(5 pCi/g), and Th-228 (1.3 pCi/g) are above the "POTW Screening Concentration" in column 3
of Table 6.2.

Using the DSRs in Table 6.2, the non-radon doses from 1-131 (44.2), K-40 (1.2), Ra-226 (1.9),
Ra-228 (2.6), and Th-228 (1.2) add up to 51.1 mrem/year.

The estimated radon concentrations due to Ra-226 are 0.005 WL or 3.0 pCi/Liter of Rn-222.
The radon concentrations due to Th-228 are 0.06 WL or 31.5 pCi/Liter of Rn-220. The total
Working Levels is 0.07 WL.

These results may warrant additional investigation, such as through a professional health
physicist or consultant. For the radon concentrations, radon monitoring could be performed, or
additional  estimates could be calculated using Screening Calculation D.

Screening Calculation D:

In Sample 2, the concentrations are Ra-226 (2 pCi/g) and Th-228 (1.3 pCi/g). The POTW room
parameters are VTOOm = 70,000 m3, hroom = 4 m, Aiudge =1.5 g/cm3, Fsiudge = 15,000 m3,
^sludge = 7500 m2, and Rx = 2 per hour.

The concentration of Rn-222 from Ra-226 is

       2 x 1.49 / 2.008 x 1.5 x 15,000 / 70,000 = 0.5 pCi/liter
       2 x 0.00931 / 2.008 / (2.25 + 2) x 1.5 x 15,000 / 70,000 = 0.0007 WL
The concentration of Rn-220 from Th-228 is

       1.3 x 720 / 47 x 1.5  x 7,500 / 70,000 = 3.2 pCi/liter
       1.3 x 3.00 / 477 (0.4 +2) x 1.5 x 7,500 / 70,000 = 0.006 WL

These radon concentrations may not warrant additional investigation.
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Example 3:   Non-POTW Radiation Exposure Estimates for a High
                NORM Sludge

Screening Calculation B:

In Sample 1, the levels of Ra-226 (25 pCi/g), Ra-228 (38 pCi/g), Th-228 (9 pCi/g),  and U-234
(4.3 pCi/g) are above the Screening Concentration. In addition, the level of Ac-227 inferred
from Th-227 (0.5 pCi/g) is also above the Screening Concentration.

Using the DSRs in Table 6.5, the screening doses for Ac-227 (5.9 mrem/yr), Ra-226 (24.6),
Ra-228 (15.6), Th-228 (4.7), and U-234 (1.0) added together give a total upper bound dose of
51.8 mrem/yr.

The inferred Rn-222 concentration from Ra-226 is 0.44 pCi/liter.

Additional calculations for non-POTW exposure are probably warranted.

Screening Calculation C:

The radionuclide samples are the same as above.

Screening calculation B indicated a need for a more detailed evaluation.  The POTW is currently
incinerating sludge, so the incinerator scenario will be evaluated. The POTW is considering
changing to agricultural application, so will examine the Onsite Resident, Nearby Town, and
Sludge Application Worker scenarios for  1, 5, and 20 years.

The results of calculations are:

•  Incinerator Scenario: Doses from Ac-227 (5.9), Ra-226 (2.2), Ra-228 (1.0), Th-228 (4.7), and
   U-234 (1.0) sum to 14.8 mrem/yr.

•  Onsite Resident
   — 1 year  of application: Doses from Ac-227 (0.005), Ra-226 (1.23), Ra-228 (1.35), Th-228
      (0.13), and U-234 (0.004) sum to 2.7 mrem/yr.

   — 5 years of application: Doses from Ac-227 (0.02), Ra-226 (6.1), Ra-228 (6.5), Th-228
      (0.4), and U-234 (0.02) sum to 13  mrem/yr.

   — 20 year of application: Doses from Ac-227 (0.08), Ra-226 (24.6), Ra-228 (15.7), Th-228
      (0.4), and U-234 (0.08) sum to 41  mrem/yr.

•  Nearby Town
   — 1 year  of application: Doses sum to 0.01 mrem/yr.

   — 5 years of application: Doses sum  to 0.06 mrem/yr.

   — 20 years  of application: Doses sum to 0.16 mrem/yr.

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•  Sludge Application Worker

   — 1 year of application: Doses sum to 0.5 mrem/yr.

   — 5 years of application: Doses sum to 2.7 mrem/yr.

   — 20 years of application: Doses sum to 8.2 mrem/yr.

Radon concentrations for the Onsite Resident on relevant for Ra-226 and Th-228:

•  1 year of application: Total 0.0002 Working Levels, including 0.02 pCi/liter Rn-222 and
   2e-6 pCi/liter Rn-220.

•  5 years of application: Total 0.0008 Working Levels, including 0.1 pCi/liter Rn-222 and
   5e-6 pCi/liter Rn-220.

•  20 years of application: Total 0.003 Working Levels, including 0.4 pCi/liter Rn-222 and
   6e-6 pCi/liter Rn-220.

Example 4:   Non-POTW  Radiation Exposure Estimates for a Typical
                Sludge

Screening Calculation B:

For Sample 3, only the levels of Pb-210 (8 pCi/g) and Ra-226 (4 pCi/g) were above the
Screening Concentration in column 3 of Table 6.5.

The screening doses for Pb-210 (2.3) and Ra-226 (3.9) added together give 6.2 mrem/year.

The inferred Rn-222 concentration from Ra-226 is 0.07 pCi/liter.

Additional calculations for non-POTW exposures are probably not needed unless more than
20 years of land application are anticipated.
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APPENDIX L
ANALYSIS OF ISCORS SURVEY AND DOSE ASSESSMENT
RESULTS

The ISCORS Survey (Survey), which measured 45 radionuclides, can provide perspective to the
POTW operator in determining which radionuclides are more likely to persist in the
environment, what potential dose they may contribute to a member of the general public or to a
POTW worker, and which radionuclides may be included initially in any sludge monitoring
program that the POTW operator may decide to conduct.

The ISCORS Sewage Sludge Subcommittee sent questionnaires to 631 POTWs with the greatest
potential to receive elevated levels of man-made and natural radiation. Selection of these
POTWs was based on criteria that the Subcommittee felt would identify sludges with elevated
levels of radiation. The 631 POTWs selected are not, therefore, statistically representative of the
more than 16,000 POTWs across the country.  From this population, 313 POTWs voluntarily
provided samples of sewage sludge and ash to be analyzed for radionuclide levels.  Of the
45 radionuclides measured, the major contribution to estimated dose is from NORM/TENORM
sources, and the critical pathway is inhalation of indoor radon from Ra-226 and Th-228. Highest
potential doses are associated with two specific scenarios (POTW worker and Onsite Resident)
of the seven scenarios that were evaluated in the ISCORS Dose Modeling Project, as shown in
Table 3.6. Radon is responsible for most of the calculated doses, and gamma ray exposure from
radium for much of the remainder. The other radionuclides detected in the survey account for
relatively minor contributions to dose. The analysis presented here is designed to illustrate the
thought processes that may be used to determine what specific radionuclides and possible
sources should be analyzed first, if a POTW operator decides that sewage sludge or ash samples
will be taken on a one-time, or a periodic basis.

Onsite  Resident Scenario

Of the 45 radionuclides detected in the Survey, less than 10 percent have the potential to
contribute significantly to the onsite resident dose, due to their relatively long half lives.
Table L.I provides a listing of 4 radionuclides that could possibly be significant, in decreasing
rank order.  This list of 4 radionuclides was developed by calculating the contribution to dose of
each radionuclide, relative to the single radionuclide (Ra-226) that presents the greatest
contribution to dose in the onsite resident scenario. The 50 mrem per year total dose comprises
of 40 mrem per year from radon (0.23 pCi/L) and 10 mrem per year from non-radon sources.
Each radionuclide in Table L. 1 contributes greater than 1  mrem per year. An effective dose
equivalent of 1 mrem per year per source or practice is recommended as the Negligible
Individual Dose by the National Council on Radiation Protection and Measurements
(e.g., NCRP No. 116.).  Such a dose is also consistent with the standard—American National
Standards Institute (ANSI)THealth Physics  Society (HPS) N13.12-1999 for control  of solid
materials which  is being evaluated along with other views by NRC in clearance rulemaking on
controlling the disposition of solid materials (68 Federal Register 9595, February 28, 2003).
ISCORS Technical Report 2004-04               L-l                          Final, February 2005

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POTW Worker Loading Scenario

For the POTW Worker Loading scenario, a 1 mrem per year cutoff was used, as described
above, to eliminate from further consideration those detected radionuclides that provide little or
no contribution to dose. In this scenario, there are 4 radionuclides of potential concern, out of
the 45 detected, with relative contributions shown in Table L.2. All of these radionuclides are
included in the onsite resident scenario except for 1-131 and Th-228. Consequently, the total
number of radionuclides that may be of concern is reduced to about one-third, from 45 to 6.

These six radionuclides are recommended to be the ones that the POTWs should first focus their
attention in terms of reducing dose to workers and onsite residents.  The six radionuclides of
primary concern are radium-226 and radium-228, which are NORM or TENORM; thorium-228,
thorium-230, and lead-210, which are either NORM/TENORM or source material; and
iodine-131, which is a byproduct material used in medical applications.

Further Explanation of Analysis

The following discussion should provide more detailed explanation  of the analyses performed,
which lead to the data contained in Tables L. 1-L.5.

By concentration, the 45 radionuclides are divided into three groups as shown in Tables L.3, L.4,
and L.5. They are ranked in decreasing order of concentration according to the upper bound of
95% of the samples, from the highest, 1-131  (#1) at 51 pCi/g to the lowest, Rn-219 (#45), at no
detect (ND).  The maximum concentration in pCi/g, percent of samples detected, a probable
source of the radionuclide, half-life, and relative contributions to dose  are also listed.

As shown in Table 3.6, two scenarios are chosen from the 7 scenarios investigated because they
represent the ones where the doses are the greatest. These scenarios are the Onsite Resident and
a POTW Worker Loading Sewage Sludge. For each radionuclide, the  Relative Contribution to
the Dose of the Worker Loading at the 95% peak dose is computed alongside the Relative
Contribution of an Onsite Resident at the 95% peak dose in a house built on land with sludge
applied for 20 years as shown in Tables L.3, L.4, and L.5. Although doses are potentially
significant, there are very few land application sites in the country that are known to have
applied sewage sludge annually for even 20 years.

Table 3.6 shows that for the  Onsite Resident Scenario, the dose is estimated to be 55 mrem per
year. For the POTW Worker Loading Scenario, the 95% peak dose is  estimated to be 24  mrem
per year. For this estimate, the air exchange rate is 3 per hour, the room height is 4 meters, and
the worker loads for 1000 hours per year. Ra-226 (#5 shaded) and Th-228 (#13 shaded) are the
main contributing radionuclides by means of the radon pathway, as shown in Table L.3.  For the
POTW Worker Loader, to obtain the Relative Contribution to dose,  the product of the
concentration and Dose to Source Ratio for Th-228 is normalized at 1000, whereas for the Onsite
Resident, for Ra-226, the Relative Contribution is normalized at 1000. The Relative
Contributions for other radionuclides are computed from normalizing the product of the
concentration and the Dose to Source Ratios and scaling factor given in Table 6.1 for the  Onsite
Resident and Table 6.14 for the POTW Biosolids Loading Working Scenario, as presented in the
Dose Assessment Report, Summary of Dose-to-Source Ratios (ISCORS 2004).

ISCORS Technical Report 2004-04                L-2                           Final, February 2005

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The sum of the doses from the radionuclides in Tables L. 1 and L.2 give doses of 55 mrem per
year and 37 mrem per year compared to Table 3.6 (55 mrem per year and 24 mrem per year)
because the 95% concentration for each radionuclide may reside in different samples. In
Table 3.6, the total dose for each sample was calculated and then the 95% of those doses was
taken.  This method explicitly incorporates the correlations (or lack thereof) among the different
radionuclides.

The radionuclides most likely to be detected are those having concentrations greater than
4 pCi/g, and present in a high percentage of the samples, are indicated in Table L.3. Radium-226
is a main contributor for the POTW Worker Loading and Onsite Resident Scenarios.
Radium-226, which is a naturally-occurring element in soils located mainly in the Atlantic and
Interior Plains, was measured in 93% of the samples from POTWs. The highest concentrations
of Ra-226 occur in POTWs where the influent comes from ground water. Th-228 is another
main contributor, but only for a Worker Loading. Th-228 is also naturally-occurring, and was
detected in 100% of the samples.  The highest concentrations of Tyh-228 occur in POTWs where
the influent comes from ground water and has an average daily flow of less than 10 MGD.
However, it is a relatively minor contributor to an Onsite Resident.  The main reason is the
relatively short half-life of 2 years for Th-228 compared to  1600 years for Ra-226 that permits
Th-228 to decay to lower levels during  the 20 years of sludge application. Additional details
about relationships between POTW characteristics and radionuclide concentrations are provided
in the ISCORS survey report (ISCORS  2003).

There are specific radionuclides of interest, such as Co-60 (#35 shaded), which is a product of
activation and has a 5-year half-life. Co-60 is of great concern because it had been detected in
certain POTWs (see Chapter  1) and has resulted in a great deal of expense to contain. However,
Co-60 contributes only a small amount  to Worker Loading dose or Onsite Resident dose as
Table L.5  shows.  Furthermore, Co-60 was detected in only 4% of the samples.

Another example is Am-241 (#37 shaded), with a half-life of 432 years, and which is a decay
product of Pu-241. It is widely used in smoke detectors employed in homes and commercial
buildings. Am-241 was detected in sludge products at various POTWs (see Table 1.1 of
Chapter 1). Am-241 is now of minor concern for the Onsite Resident where it is about 0.1%
relative to Ra-226 and was detected in only 3% of the samples.

Therefore, based on conservative assumptions, there are no cases where the 95th percentile dose
exceeds the limit of total radiation exposure of 100 mrem per year to individual members of the
general public from all controllable sources as recommended by international and national
radiation protection advisory  bodies (International Commission on Radiological Protection and
National Council on Radiation Protection and Measurements).  This conclusion suggests that
doses from exposure to radionuclides in sewage sludge and ash are below the current limit of
total radiation exposure, based on the ISCORS Survey and Dose Assessment. This observation
is further qualified since samples from the 313 POTWs included in the Survey were received
from 631 POTWS specifically selected as having the greatest potential to receive radionuclides
from licensees or from naturally-occurring sources out of more than  16,000 POTWs across the
country.
ISCORS Technical Report 2004-04                L-3                          Final, February 2005

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 Table L.1     Radionuclides that May be of Concern for Onsite Resident
 There are 4 radionuclides with a dose from 1.2 to 50 mrem/y.  Their relative contributions to
 the dose range from 24 to 1000 at 95% concentration.  Forty-one radionuclides have relative
 contributions less than 24.
Rank
1
2
O
4
Radionuclide
Ra-226
Ra-228
Th-230
Pb-210
Dose (mrem/y)
50*
2.1
1.3
1.2
Relative Contribution
1000
42
25
24
* 40 mrem/y radon dose (0.23 pCi/L); 10 mrem/y non-radon dose.
Table L.2    Radionuclides that May be of Concern for Worker Loading
There are 4 radionuclides with doses ranging from about 1.3 mrem/y to 20 mrem/y.
Their relative contribution to the dose ranges from 65 to 1000 at 95% concentration.  Forty-one
radionuclides have relative contributions less than 65. Note: Air exchange rate = 3 per hour,
room height = 4 meters, and time exposed to sludge = 1000 hours per year.
Rank
1
2
3
4
Radionuclide
Th-228
Ra-226
1-131
Ra-228
Dose (mrem/y)
20*
lit
4.7
1.3
Relative Contribution
1000
550
240
65
* 14 mrem/y radon dose (17 pCi/L); 6 mrem/y non-radon dose.
•f 9 mrem/y radon dose (0.9 pCi/L); 2 mrem/y non-radon dose.
ISCORS Technical Report 2004-04
L-4
Final, February 2005

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Table L.3     Radionuclides Most Likely to be Detected, Greater than 4 pCi/g for
              the 95th Percentile Concentration and High Percent of Samples
They are ranked in decreasing order of concentration. The maximum concentration, percent of
samples detected, probable source and half-life are also listed. Finally, the Relative Contribution
to the dose of a Worker Loading at a POTW (air exchange rate = 3 per hour, room height = 4
meters, and time exposed to sludge = 1000 hours per year) at the 95% peak dose is listed next to
the Relative Contribution of an Onsite Resident at the 95 % peak dose after 20 years of
application.
Rank
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
Radio-
nuclide
[-131
TL.201
Sr-89
U-234
Ra-226
U-238
K-40
Be-7
Pa-234m
Th-234
Ra-228
H-3
Th-228
Concentration
(pCi/g)
95%-tile
51
46
20
17
13
12
12
9
7
6.7
5.1
5
4.1
Max
840
241
70
44
47
26
26
22
27
23
38
8
9
Percent
Samples
Detected
246/311= 84
151/311= 49
68/98= 70
92/92=100
289/311= 93
92/92= 100
308/311= 99
263/311= 85
80/311= 86
191/311= 29
271/311= 87
111/158= 70
92/92= 100
Probable source
Medical, Pacific mountain,
and 50-100 MOD
Medical, Appalachian
Highlands, 50-100 MOD
Medical
U-processing Intermontane
Plateaus
NORM, Atlantic & Interior
Plains, ground water
Appalachian Highlands,
Intermontane Plateaus
NORM, all geographic
regions
NORM, Appalachian
Highlands
U-238 decay
U-238-decay, Intermontane
Plateaus, Rocky Mt.
NORM, Interior Plains,
ground water, < 10 MOD
Academic/Medical/Research
NORM, Interior and Atlantic
Plains, ground water, < 10
MOD
Half-life
8d
3d
51 d
245xl03y
1600 y
4.5xl09y
1.3xl09y
53d
1m
24 d
6y
12 y
2y
Relative
contribution,
95%-ile
Worker
Loading
240
23
<1
5
550
6.8
27
5.5
<1
<1
65
<1
1000
Onsite
Resident
(20 y)
<1
<1
<1
6.2
1000
4.4
2.3
<1
<1
<1
42
<1
4.4
ISCORS Technical Report 2004-04
L-5
Final, February 2005

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Table L.4     Radionuclides Somewhat Likely to be Detected, 95th Percentile
              Concentration >ND and <4 pCi/g , and Percent Samples
              Generally Low
They are ranked in decreasing order of concentration. The maximum concentration, percent of
samples detected, probable source and half-life are also listed. Finally, the Relative Contribution
of a Worker Loading at a POTW (air exchange rate = 3 per hour, room height = 4 meters, and
time exposed to sludge = 1000 hours per year) at the 95% peak dose is listed next to the Relative
Contribution of an Onsite Resident at the 95 % peak dose after 20 years of application.
Rank
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
Radio-
nuclide
Pb-210
Pb-214
Bi-214
Pb-212
Bi-212
Sr-90
C-14
Th-230
Tl-208
Ra-224
Tl-202
Th-232
U-235
Cs-137
Th-227
Pu-238
In-Ill
Pu-239
Concentration
(pCi/g)
95%-ile
4
2.6
2.3
1.9
1.3
1
1
1
0.96
0.9
0.53
0.6
0.45
0.11
0.1
0.07
0.04
0.04
Max
13
17
16
15
13
9.4
3
1.7
4.8
12
1.16
1.6
3.1
3.6
0.5
0.19
3.6
0.12
Percent
Samples Detected
135/311= 43
253/311= 81
238/311= 77
303/311= 97
101/311= 32
64/98= 65
62/158= 39
92/92= 100
180/311= 58
47/311= 15
73/311= 23
92/92= 100
112/311= 26
133/311= 43
49/207= 24
75/92= 82
19/311= 6
68/92= 74
Probable source
(only key sources
are identified)
Uranium, Pacific
Mountains




Academic
Academic
Uranium,
Appalachian
Highlands, Atlantic
and Interior Plains



U mills,
Appalachian
Highlands






Half-life
22 y
27m
20m
llh
61m
29 y
5730 y
77 x 103 y
3m
4d
12 d
14xl09y
700 x 106y
30 y
19 d
88 y
3d
24 x 103 y
Relative contribution,
95%-ile
Worker
Loading
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
2.5
<1
<1
<1
<1
<1
<1
Onsite
Resident
(20 y)
24
<1
<1
<1
<1
7.2
9.6
25
<1
<1
<1
13
<1
<1
<1
<1
<1
<1
ISCORS Technical Report 2004-04
L-6
Final, February 2005

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Table L.5    Radionuclides Least Likely to be Detected, No Detect (ND) for the
             95th Percentile and 4 or Less Percent of Samples Detected, Ranked
             in Decreasing Order  of Maximum Concentration
The maximum concentration, percent of samples detected, probable source and half-life are also
listed. Finally, the Relative Contribution to the dose of a Worker Loading at a POTW (air
exchange rate = 3 per hour, room height = 4 meters, and time exposed to sludge = 1000 hours
per year)at the 95%  peak dose is listed next to the Relative Contribution of an Onsite Resident at
the 95 % peak dose  after 20 years of application.  The max is used as the concentration to give
an extreme relative dose.
Rank
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
Radio-
nuclide
1-125
Sm-153
Eu-154
Co-60
Cr-51
Am-241
Fe-59
Co-57
Ra-223
La-138
Zn-65
Cs-134
Ce-141
Rn-219
Concentration
(pCi/g)
95%-ile
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Max
40
27
21
5.1
3.5
2.5
0.4
0.26
0.09
0.07
0.06
0.04
0.016
ND
Percent
samples
detected
11/311=4
1/311=0.3
1/311=0.3
13/311=4
6/311=2
10/311=3
1/311=0.3
13/311=4
2/311=0.6
1/311=0.3
1/311=0.3
1/311=0.3
1/311=0.3
0/311=0
Probable source
(only key sources are
identified)


Medical
Academic/Industry

Smoke detector
Industry







Half-life
60 d
47 h
9y
5y
28 d
432 y
45 d
271 d
lid
135xl09y
244 d
2y
33d
4s
Relative contribution,
95%-ile
Worker
Loading

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