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Internal SFUND Box Number _35_ OF 283_ 

Initials/Date: LDS / 3-8-2007 
\oa$qx^s-\43 

TECHNICAL BACKGROUND DOCUMENT TO SUPPORT 

FINAL RULEMAKING PURSUANT TO SECTION 102 OF THE 

COMPREHENSIVE ENVIRONMENTAL RESPONSE, COMPENSATION, 

AND LIABILITY ACT: RADIONUCLIDES 

A Report to the 

EMERGENCY RESPONSE DIVISION 

Office of Emergency and Remedial Response 

U.S. Environmental Protection Agency 

February 1989 

Prepared by: 

ICF INCORPORATED and 

C-E ENVIRONMENTAL 

EPA Contract 68-03-3452 
P.4 

TABLE OF CONTENTS 

Page 

CHAPTER 1: BACKGROUND AND INTRODUCTION 1-1 

1.1 Background on CERCLA and RQ Notification Requirements 1-1 

1.2 RQ Adjustments for Radionuclides 1-2 

1.3 The Scope of the Radionuclide Release Problem 1-5 

1.3.1 The Affected Community 1-6 

1.3.2 Radionuclide Release History 1-9 

1.4 Organization of This Report 1-10 

CHAPTER 2: OPTIONS FOR THE ADJUSTMENT OF RADIONUCLIDE RQs 2-1 

2.1 Option 1: Allowing the Radionuclide RQ to Remain at 

One Pound 2 -.1 

2.2 Option 2:. Considering Radionuclides as a Generic Class 

of Substances, Without an RQ and Not Subject to CERCLA 

Reporting Requirements 2-2 

2.3 Option 3: Establishing a Dose-Equivalent Level as the 

Radionuclide RQ 2-3 

2.4 Option 4: Considering Radionuclides as a Class With a 

Single Activity Level 2-4 

2.5 Option 5: Grouping Radionuclides into Categories With 

an Activity Level Assigned to Each of the Separate 

Categories 2-4 

2.6 Option 6: Establishing an Activity Level RQ for 

Individual Radionuclides 2-6 

CHAPTER 3": MAJOR ISSUES ASSOCIATED WITH THE SELECTED RQ 

ADJUSMTNET METHODOLOGY 3-1 

3.1 Departure from the Methodology for Adjusting RQs 

of Potential Carcinogens 3-2 

3.2 Incorporation of Radioactive Decay 3-2 

3.3 Assumed Distance Between the Point of Release and 

Point of Exposure 3-3 

3.4 Assumed Configuration of Radionuclide Release 3-4 
P.5 

TABLE OF CONTENTS 

(continued) 

Page 

3.5 Modeling of Potential Exposures Through the Ingestion 

of Contaminated Vegetables 3-5 

3.6 Additional Exposure Pathway Models 3-6 

CHAPTER 4: METHODOLOGY FOR RQ ADJUSTMENTS 4-1 

4.1 Overview of the Methodology 4-1 

4.2 Release Values for the Inhalation Pathway 4-2 

4.3 Release Values for the Ingestion of Water 4-5 

4.4 Release Values for the Ingestion of Food 4-9 

4.5 Release Values for the Direct Exposure Pathway 4-12 

4.5.1 Direct Exposure from a Point Source 4-12 

4.5.2 Submersion in a Radioactive Cloud of Noble Gas 4-16 

4.6 Assignment1 of Radionuclides to RQ Groups 4-18 

4.7 Reporting Requirements for Mixtures of Radionuclides 4-19 

4.7.1 Mixtures of Known Composition 4-19 

4.7.2 Mixtures of Unknown Composition 4-20 

4.7.3 Common Radionuclide Mixtures 4-20 

4.8 Reporting Requirements for Compounds and Mixtures of 

Radionuclides and Other Hazardous Substances 4-21 

APPENDIX A: Modeling the Airborne Release and Inhalation of 

Radionuclides A-l 

APPENDIX B: Modeling the Ingestion of Contaminated Drinking 

Water B-l 

APPENDIX C: Modeling the Ingestion of Contaminated Foodstuffs C-l 

APPENDIX D: Modeling of Direct Exposure to Radionuclides D-l 

APPENDIX E: Release Values and Final RQs E-l 
P.6 

CHAPTER 1 

BACKGROUND AND INTRODUCTION 

This report discusses the options that were considered by the U.S. 

Environmental Protection Agency (EPA) for adjusting the one-pound statutory 

reportable quantity (RQ) for radionuclides, and presents in detail the option 

and method the Agency has selected. 

This chapter outlines the general reporting requirements under sections 

103(a) and (b) of the Comprehensive Environmental Response, Compensation, and 

Liability Act (CERCLA) and the specific reporting requirements for 

radionuclides. Section 1.1 describes CERCLA reporting requirements and the 

types of potential response activities triggered by CERCLA reporting; Section 

1.2 describes the statutory authority for and the intended purpose of the RQ 

adjustment for radionuclides; Section 1.3 explains the scope of the 

radionuclide release problem; and Section 1.4 introduces the remaining 

chapters of this report. 

1.1 BACKGROUND ON CERCLA AND RQ NOTIFICATION REQUIREMENTS 

CERCLA, as amended by the Superfund Amendments and Reauthorization Act of 

1986 (SARA), establishes broad federal authority to respond to releases or 

threats of releases of hazardous substances from vessels and facilities. The 

Act requires immediate notification to the National Response Center when a 

hazardous substance designated under CERCLA is released into the environment 

in an amount equal to or greater than the RQ for that substance. 

Section 101(14) of CERCLA defines as a CERCLA hazardous substance any 

substance designated under: 

o Sections 307 and 311 of the Clean Water Act; 

o Section 3001 of the Resource Conservation and 

Recovery Act; 

o Section 112 of the Clean Air Act; and 

o Section 7 of the Toxic Substances Control Act. 

In addition, EPA has the authority under section 102(a) of CERCLA to designate 

additional hazardous substances. Currently, there are 721 CERCLA hazardous 

substances, excluding radionuclides. Radionuclides are hazardous substances 

under CERCLA because they were designated generically as a hazardous air 

pollutant pursuant to section 112 of the Clean Air Act. Section 102(b) of 

CERCLA establishes a one-pound RQ for radionuclides, but section 102(a) 

authorizes EPA to adjust this statutory RQ by regulation. RQ adjustments for 

radionuclides were proposed in a Notice of Proposed Rulemaking on March 16, 

1987 (52 FR 8172). 

Under regulations implementing the general reporting requirements of 

sections 103(a) and (b) of CERCLA, a person in charge of a vessel or facility 

is required to notify the National Response Center immediately when there is a 

release of a designated hazardous substance in an amount that equals or 
P.7 

1-2 

exceeds the RQ for that substance (40 CFR 302.6(a)). In addition, SARA 

section 304 requires facility owners or operators to immediately notify state 

and local officials after the release of an RQ or more. SARA section 304 

notification requirements apply only to releases that have potential for offsite exposure and that are from facilities that produce, use, or store a 

"hazardous chemical," as defined by regulations under the Occupational Safety 

and Health Act of 1970 (29 CFR 1910.1200(c)) and section 311 of SARA. Those 

persons required to notify but who knowingly fail to report immediately the 

release of an RQ are subject to criminal penalties under CERCLA section 

103(b). Releases that are federally permitted, as defined by section 101(10), 

are exempt from the Section 103 notification requirements. 

It is important to clarify that the immediate reporting requirements of 

CERCLA section 103 apply to releases of an RQ or more within a 24-hour period. 

Persons who frequently release an RQ or more in 24 hours may qualify for 

reduced reporting. Specifically, section 103(f)(2) of CERCLA provides a 

reduced reporting provision for releases of an RQ or more that are 

"continuous" and "stable in quantity and rate." Such releases only need to be 

reported annually and when there is a statistically significant increase in 

the quantity of the hazardous substance released. Persons who do not release 

an RQ in 24 hours do not have to report at all. 

The purpose of RQ notification is to alert appropriate government 

agencies to releases of hazardous substances that may require rapid response 

to protect public health or welfare or the environment. For example, under 

section 104 of CERCLA, the federal government may take response action 

whenever there is a release or a substantial threat of a release of a 

hazardous substance or of any pollutant or contaminant that may present an 

imminent and substantial danger to public health or welfare. Notification 

based on RQs serves to inform the government of a release, thereby enabling an 

evaluation of the situation and a timely field response should one be deemed 

necessary. The release of an RQ does not necessarily mean that there will be 

a hazard. Similarly, notification does not necessarily mean that a federal 

field response will occur, nor does it eliminate liability or responsibility 

for response costs or natural resource damages associated with the release. 

1.2 RQ ADJUSTMENTS FOR RADIONUCLIDES 

There are approximately 1,500 known radionuclides. A radionuclide is an 

isotope with an unstable combination of protons and neutrons in its nucleus. 

Instability is the result of an imbalance in repulsive and attractive forces 

between these two types of nuclear particles. To achieve a more stable 

configuration, the nucleus releases energy in the form of particles or rays by 

a process of decay called radioactivity. Each radionuclide decays by a 

specific mechanism and at a specific rate and, as a result, a pound of two 

different radionuclides could represent significantly different types and 

levels of radioactivity. 

^Notification to the National Response Center pursuant to CERCLA section 

103 is limited to releases of designated hazardous substances in amounts that 

equal or exceed the applicable RQ. Releases consisting solely of pollutants 

or contaminants that are not designated as hazardous substances under CERCLA 

need not be reported to the National Response Center. 
P.8 

1-3 

There are four types of emissions from radionuclides during the decay 

process that may have a significant impact on human health or welfare or the 

environment: alpha particles, beta particles, gamma rays, and neutrons (which 

are also particles). The particles and rays differ in their mass, charge, 

energy content, and range of penetration and potential damage in surrounding 

media. 

Alpha particles consist of two protons and two neutrons and have a 

positive charge of 2. Alpha particles possess energies in the range of 2 to 

12 million electron volts (MeV), with typical values falling between 4 and 9 

MeV. Alpha particles travel only short distances in matter and are highly 

disruptive in tissue because of their large mass, relatively high speed, and 

large charge. In general, alpha particles present no external hazard because 

of their short range, but do present a significant internal hazard when taken 

into the body. 

Beta particles are either electrons or positrons (positively charged 

electrons). The energy range of beta particles is 0.02 MeV to 14 MeV, with 

typical values falling between 0.04 and 6 MeV. Beta particles are more 

penetrating (i.e., have a longer range in matter) than alpha particles, and 

are more easily scattered and are less disruptive than alpha particles. Beta 

particles are primarily internal hazards, although certain high energy beta, 

particles also may present an external hazard at relatively close range. 

Gamma rays are photons that have no mass and no charge, and possess 

energies in the range of 0.01 to 10 MeV. Gamma rays are not scattered easily, 

can be very penetrating, and are of most concern as potential external 

hazards. 

Neutrons have no net charge and a mass that is slightly larger than that 

of a proton. They are emitted from a variety of sources, most of which are 

man-made (e.g., mixtures of certain radioactive sources and target substances, 

collisions of high-speed particles in accelerators, and fissions in a nuclear 

reactor). However, neutrons also may be emitted naturally from a handful of 

transuranic elements and uranium isotopes that undergo spontaneous fission. 

Along with gamma rays, neutrons are of most concern as potential external 

hazards. 

As noted previously, radionuclides were designated generically as 

hazardous air pollutants under section 112 of the Clean Air Act and are, 

therefore', designated CERCLA hazardous substances. Section 102 of CERCLA 

establishes a one-pound reportable quantity for radionuclides, as a generic 

class of substances, but authorizes EPA to adjust this RQ by regulation. EPA 

recognizes that an RQ of one pound for radionuclides is not an appropriate 

level in most cases because releases of less than one pound of a radionuclide 

may present a substantial danger to public health or welfare or to the 

environment. In addition, "pound" units are not commonly used for measuring 

quantities of radionuclides. 

CERCLA hazardous substances other than radionuclides have reportable 

quantities ranging from one pound to 5000 pounds. For these substances, the 

principal health concerns are chemical toxicity, ignitability, reactivity, or 

potential carcinogenicity. These criteria may be related to a specific number 

of pounds of the hazardous substance released. Radionuclides are very 
P.9 

1-4 

different from other CERCLA hazardous substances because the principal health 

hazard associated with most radionuclides is the potential for cancer caused 

by exposure to radioactivity. Although the level of radioactivity for a given 

radionuclide is directly proportional to its mass, equal masses of different 

radionuclides will not produce equal adverse health and environmental effects. 

For this reason, activity levels are used most generally as indicators of 

radiation intensity and potential hazard. The quantity of radioactivity is 

measured in units of curies^ (Ci) and, for different radionuclides, the same 

number of pounds translates into a different number of curies. Thus, the 

statutory one-pound RQ translates into a wide range of curies for different 

radionuclides, covering at least twenty orders of magnitude. 

In addition to curies, another widely used unit for measurement of 

radiation hazard is the rem (originally Roentgen Equivalent Man). The rem is 

a unit of measure for radiation dose-equivalent and is often expressed as some 

number of rem delivered to a specific organ such as the lungs, thyroid, or 

whole body. Whereas the curie is a measure of the quantity of radiation 

emitted, the dose-equivalent directly reflects the level of tissue damage. 

Curies can be converted into rem by considering an exposure scenario defined 

by such factors as the radionuclide identity, route and duration of exposure, 

quantity of intake, tissues most affected, type of radiation, and other 

factors that determine the hazardous effects of the radiation. 

The nuclear industry in the United States generally uses units of curies 

and rem and, in fact, most existing reporting triggers for radionuclide 

releases are expressed in terms of one or the other, or both, of these two 

units. In addition, essentially all existing regulations and controls 

established by the Nuclear Regulatory Commission and the Department of Energy, 

which govern a major portion of the nuclear industry, are based on units of 

curies or rem. Therefore, for the RQ under CERCLA to be consistent and 

meaningful, and to ensure that the radionuclide RQ allows for timely reporting 

and timely field response, if necessary, the statutory one-pound RQ is being 

adjusted by regulation. The RQ adjustments are in units of curies. 

The Agency is adjusting the RQ for 757 specific radionuclides for which 

the International Commission on Radiological Protection (ICRP) has provided 

metabolic data and recommended intake limits in ICRP Publication 30.4 All 

radionuclides not listed by the ICRP are grouped into a generic class of 

"radionuclides," with one RQ for the entire class. Chapters 3 and 4 of this 

report discuss the RQ adjustment process in more detail. 

^The curie is a measure of the rate of radioactive decay, with one curie 

equal to 3.7 x 10-1-

0 disintegrations per second. 

JRadiation measurements can also be expressed in international metric units 

of becquerels or sieverts; however, these terms are less common in the United 

States. 

^International Commission on Radiological Protection, Annals of the 

ICRP: Limits for Intakes of Radionuclides bv Workers. ICRP Publication 30, 

Part 2, 1980. 
P.10 

1-5 

The harmful effects of radiation on humans has been the focus of most of 

the research efforts concerning radiation exposure in the past. EPA's mandate 

under CERCLA is, of course, concerned with the broader problem of potentially 

deleterious effects to the environment as well as to humans. In adjusting the 

radionuclide RQ, the Agency's goal is to ensure, to the extent possible, ample 

protection for the most sensitive species of flora and fauna. The Agency 

reviewed the existing literature and determined that present information 

indicates that protection of human health would be sufficiently protective of 

the environment as well. The National Academy of Science states: 

The principal potential impact of radioactive effluents on 

the biosphere is the induction of deleterious health 

effects in man. Comparable levels of impact undoubtedly 

exist in other biota, but there is no present evidence 

that there is any biological species whose sensitivity is 

sufficiently high to warrant a greater level of protection 

than that adequate for man. 

In addition, the ICRP has stated as part of its recommended objectives that: 

Although the principal objective of radiation protection 

is the achievement and maintenance of appropriately safe 

conditions for activities involving human exposure, the 

level of safety required for the protection of all human 

individuals is thought likely to be adequate to protect 

other species, although not necessarily individual members 

of those species. The Commission therefpre believes that 

if man is adequately protected then other living things 

are also likely to be sufficiently protected. 

The Agency has determined, therefore, that RQ adjustments for 

radionuclides developed with the goal of protecting public health will protect 

the environment as well. 

1.3 THE SCOPE OF THE RADIONUCLIDE RELEASE PROBLEM 

Radionuclide emissions are most closely identified with the nuclear power 

industry, but are commonly released from other activities as well. The 

National Academy of Sciences, The Effects on Population of Exposure to 

Low Levels of Ionizing Radiation. Report of the Advisory Committee on the 

Biological Effects of Ionizing Radiation, National Research Council, November 

1972, p.11. 

"International Commission on Radiological Protection, Recommendations of 

the International Commission on Radiological Protection (ICRP). Publication 

26, January 1977, p. 3. 
P.11 

1-6 

Nuclear Regulatory Commission, Agreement States, and the Department of Energy 

(DOE) all license or oversee a variety of industrial facilities and 

non-industrial operations that emit radionuclides. In addition, several 

industrial categories not licensed by the Commissi6n or an Agreement State 

potentially could release radionuclides. Coal-fired utilities and industrial 

boilers, and mineral extraction industries such as uranium, aluminum, zinc, 

copper, lead, and phosphorous mining all release certain amounts of naturally 

occurring radionuclides during their operations. This section summarizes the 

types of facilities most likely to be affected by the RQ adjustments and 

reviews briefly the available data on past radionuclide releases. 

1.3.1 The Affected Community 

The Nuclear Regulatory Commission has authority under the Atomic Energy 

Act of 1954 to license source, byproduct, and special nuclear materials. 

Agreement States also have authority under the Atomic Energy Act to license 

source, byproduct, and special nuclear materials at facilities within their 

boundaries. As of 1984, there were approximately 8,900 Commission licensees 

and 13,000 Agreement State licensees. Federal licensees are subject to the 

radioactive material release limits specified in 10 CFR Part 20, as well as 

other controls specified by the license and other regulations. Agreement 

State licensees are subject to release limits and reporting requirements 

specified in relevant state regulations, which generally are at least as 

restrictive as those in 10 CFR Part 20. Source, byproduct, and special 

nuclear material licensees can be divided into the following six general 

categories: 

o power reactors; 

o research and test reactors; 

o nuclear fuel cycle facilities (other than reactors); 

'Agreement States are states that have entered into an agreement with the 

Atomic Energy Commission or the Nuclear Regulatory Commission pursuant to 

section 274 of the Atomic Energy Act of 1954, as amended, under which the 

Commission has relinquished to such states the majority of its regulatory 

authority over source, byproduct, and special nuclear material in quantities 

not sufficient to form a critical mass. 

Q 

°These terms are defined in Section 11 of the Atomic Energy Act. Source 

ooo 

material is defined as (1) natural uranium (comprised of 99.27 percent U " , 

0.72 percent U235, and 0.0057 percent U 234 ) , natural thorium (Th232), or any 

combination thereof; or (2) ores that contain 0.05 percent (by weight) of 

uranium or thorium. Special nuclear material is defined as plutonium or 

uranium enriched in the U^JJ or U^JJ isotope (i.e., U" J makes up more than 

0.72 percent by weight). Byproduct material is defined as (1) any material 

made radioactive by exposure to radiation incident to the process of producing 

or utilizing special nuclear material; or (2) the wastes produced by the 

extraction or concentration of uranium or thorium from ore (e.g., Uranium Mill 

Tailings). 

yU.S. Nuclear Regulatory Commission, 1984 Annual Report, p. 73. 
P.12 

1-7 

o radiopharmaceutical industry and medical facilities; 

o radiation source manufacturers; and 

o other licensees, including laboratories, low-level 

waste disposal sites, certain mineral and metal 

processing facilities, and certain Department of 

Defense facilities, including the Armed Forces 

Radiobiology Research Institute and nine naval 

shipyards. 

Agreement States may also license and/or regulate a fourth class of 

radioactive material called naturally occurring or accelerator-produced 

radioactive material (NARM). The States' authority to control NARM, however, 

is not federally derived because the only authority that can be relinquished 

to states by the Nuclear Regulatory Commission is the authority under the 

Atomic Energy Act to license source, byproduct, and special nuclear material. 

One large category of NARM users licensed by Agreement States is low energy 

accelerators. Such accelerators are used for a wide variety of applications, 

including radiography, activation analysis, food sterilization and 

preservation, radiation therapy, and research. As of 1984, there were an 

estimated 1,500 low energy accelerators in use in the U.S., not including 

accelerators owned by DOE. ° 

The Atomic Energy Act authorizes DOE "to protect the public health and 

safety" with respect to the operation of so-called "GOCO" facilities --

facilities that are "government owned, contractor operated." This authority 

applies to activities involving NARM, as well as activities involving source, 

byproduct, and special nuclear material. As of 1980, 78 GOCO facilities in 24 

states were subject to DOE health and safety requirements. Currently, there 

are approximately 47 DOE facilities that actively use radionuclides; some of 

these facilities, such as the Hanford Installation, actually are comprised of 

numerous separate facilities that carry out different operations. Major DOE 

facilities include national laboratories, uranium enrichment faciliites, and 

facilities associated with: nuclear weapons research, development, and 

production; medical and biological research; and industrial applications and 

development. DOE also is responsible for managing several sites that are not 

active but contain radioactive contamination, such as sites associated with 

the Formerly Utilized Sites Remedial Action Program (FUSRAP), the Uranium Mill 

Tailings Remedial Action Program (UMTRAP), the Grand Junction Remedial Action 

Program (GJRAP), and the Surplus Facilities Management Program (SFMP). 

Radionuclide release limits and reporting requirements applicable to DOE 

facilities are set forth in a series of internal DOE orders issued under the 

authority of the Atomic Energy Act. 

•"•^U.S. Environmental Protection Agency, Radionuclides Background 

Information Document for Final Rules. Volume II, October 1984, p. 3.2-6. 

•

L]-ICF estimate . 
P.13 

1-8 

Over 70 percent of the facilities that use materials containing 

radionuclides are not licensed by the Nuclear Regulatory Commission, an 

Agreement State, or by DOE. These facilities are discussed briefly below. 

Large coal-fired boilers are used to generate electricity for public and 

industrial use and to provide process steam, process hot water, and space 

heat. More than 600 million tons of coal are burned each year in utility and 

industrial boilers. Coal contains mineral matter including trace quantities 

of naturally occurring radionuclides. Uranium-238 and thorium-232 and their 

decay products are found in coal,-'-2 however, based on sample results for five 

utility boilers,

 3 less than three percent of the total quantity of 

radionuclides input from coal is usually released to the air. Solid wastes 

from coal-fired boilers (e.g., fly ash, bottom ash, slag, and scrubber 

sludges) are stockpiled commonly in large quantities on-site, and these wastes 

may contain low concentrations of naturally occurring radionuclides. 

In early 1985, there were 1,281 coal-fired units operating in the utility 

industry, with a total generating capacity of 281 gigawatts. ^ Major users of 

coal-fired industrial boilers (producing process steam and hot water, 

generating electricity for the producers' own use, and providing space heat) 

include the steel, aluminum, chemical, and paper industries. There are an 

estimated 51,187 coal-fired industrial boilers operating in the United States. 

Radionuclide emission levels from large utility boilers are generally in the 

range of 0.01 curies per day; radionuclide emission levels from the smaller 

industrial boilers are generally in the range of 0.001 curies per day.

 5 

Almost all mineral extraction industries that involve the removal and 

processing of ores to recover metal release some radionuclides. The Agency 

has identified the following mineral extraction industries as having the 

greatest potential to release radionuclides to the air: the uranium mining 

industry, the aluminum industry, the copper industry, the zinc industry, the 

lead industry, and the phosphate industry. These industries were identified 

because of the large quantity of ore mined domestically and because the mining 

and processing operations conducted create a likelihood of radionuclide 

emissions. Except for the uranium mining industry, individual radionuclide 

emission levels to the air are generally in the range of 0.001 curies to 

0.000001 curies per day from these facilities; uranium mines may emit more 

•^U.S. Environmental Protection Agency, Radionuclides Background 

Information Document for Final Rules. Volume II, October 1984, p. 4.0-1. 

13U.S. Environmental Protection Agency, Survey of Five Utility Boilers for 

Radionuclide Emissions. Final Report. Office of Radiation Programs, Washington, 

D.C., December 1983, p. 3. 

•^ICF Energy Service, Summer/Fall 1985 Coal and Electric Utilities Market 

Assessment, p. 1-2 (1985). 

•'•-'U.S. Environmental Protection Agency, Radionuclides Background 

Information Document for Final Rules. Volume II, October 1984, p. 4.1-11 and 

p. 4.2-7. 
P.14 

1-9 

than 30 curies of radon per day.-*-° Similar to coal-fired boilers, facilities 

in these industries may stockpile large quantities of solid waste containing 

generally low concentrations of naturally occurring radionuclides. There are 

numerous mines, mills, smelters, and other processing plants in each of these 

industries. 

1.3.2* Radionuclide Release History 

As part of this regulatory development process, release data were 

collected from the major federal agencies licensing, regulating, and 

controlling radionuclide releases: the Nuclear Regulatory Commission, the 

Department of Transportation, DOE, and EPA. The data were examined to 

understand the scope of the radionuclide release problem. The following 

release data were collected: 

o Reports maintained by the Nuclear Regulatory 

Commission's Office for Analysis and Evaluation of 

Operational Data (AEOD), for the years 1981 through 

1985; 

o Reports maintained by the Transportation Technology 

Center (TTC) of Sandia National Laboratory in 

Albuquerque, New Mexico, for 1971 through 1985; 

o Data provided by the Department of Energy's Office of 

Environment and Health, Emergency Operations Center 

(EOC), for March 1983 through April 1986; 

o Reports to the National Response Center, for 1982 

through 1985; 

o Reports to the EPA's Office of Radiation Programs 

(ORP), for October 1981 through September 1983; and 

o Reports to the Nuclear Regulatory Commission's 

Operations Center, for January 1983 through January 

1986. 

The availability and quality of data varied from source to source, but 

duplication among the six sources appeared to be relatively limited. 

The AEOD data include some 300 reports annually, although about two 

thirds of the reports are incidents involving monitoring compliance or some 

other technical infraction that does not involve radionuclide releases. The 

TTC data include between 1 and 12 reports annually of transportation incidents 

involving radionuclide releases. These events already are required to be 

reported to the National Response Center under Department of Transportation 

regulations (49 CFR Parts 171-177). The Department of Energy EOC data include 

52 release events over a 3-1/2 year period (between 11 and 22 events annually) 

U.S. Environmental Protection Agency, Radionuclide Background 

Information Document for Final Rules. Volume II, October 1984, p. 7.1-8, 

7.2-6, 7.3-4, 7.4-4, 6.1-11, 5-15. 
P.15 

1-10 

and include releases that are reportable under DOE Order 5484.1. The National 

Response Center data include approximately 80 reports (about 30 reports 

annually) and the ORP data include approximately 60 reports (about 30 reports 

annually). The National Response Center data include little detail on the 

radionuclide identity and the quantity released. The ORP data reflect mostly 

releases from power reactors. The final data source, the Nuclear Regulatory 

Commission Operations Center, include data on 26 events (about 8 events 

annually). 

Although the six data sources include a total of about 400 events 

annually, at least 200 of these annual events are not releases to the 

environment. Data are available, therefore, on approximately 200 release 

events annually. These data sources, however, do not cover releases from all 

facilities that handle and that are, therefore, likely to release 

radionuclides. For example, releases from unlicensed facilities and releases 

from facilities in Agreement States would not be expected to be well 

represented in the data sets. In addition, not all types of radioactive 

material is well represented. One particular type of radioactive material 

that is not well represented in the data sets is NARM. Although Agreement 

States and DOE control NARM uses at facilities under their jurisdiction, there 

are no uniform regulatory or reporting requirements for NARM. Virtually all 

states, both agreement and non-agreement, have some type of NARM regulatoryprogram, ' however, the data collected under these programs have not been 

gathered as part of this analysis because they were too diffuse. The 

available data, therefore, do not represent fully NARM releases. 

1.4 ORGANIZATION OF THIS REPORT 

This report discusses the various options considered for adjusting the 

one-pound RQ for radionuclides and examines in detail the selected option. 

The remainder of this report is organized as follows: 

Chapter 2: Options for the Adjustment of Radionuclide ROs 

--a review of the regulatory approaches considered and 

the one selected; 

Chapter 3: Major Issues Associated with the Selected RQ 

Adjustment Methodology --a discussion of major technical 

issues raised in comments on the proposed RQ rulemaking 

and changes made to the adjustment methodology in response 

' to comments; 

Chapter 4: Methodology for RQ Development - - the 

technical analysis and establishment of RQ values; 

Appendix A: Modeling the Airborne Release and Inhalation 

of Radionuclides; 

1'U.S. Nuclear Regulatory Commission, Regulation of Naturally Occurring and 

Accelerator-Produced Radioactive Materials--An Update. NUREG-0976, October 1984, 

p. 3. 
P.16 

1-11 

Appendix B: Modeling the Ingestion of Contaminated 

Drinking Water; 

Appendix C: Modeling the Ingestion of Contaminated 

Foodstuffs; 

Appendix D: Modeling of Direct Exposure to Radionuclides; 

and 

Appendix E: Release Values and Final RQs. 
P.17 

CHAPTER 2 

OPTIONS FOR THE ADJUSTMENT OF RADIONUCLIDE RQs 

Several options for adjusting radionuclide RQs were carefully examined 

during the development of the final regulation. Each option presented certain 

advantages and disadvantages but each of the rejected options was determined 

to be inferior to the selected approach. This chapter discusses the following 

regulatory options and explains the Agency's position and rationale for 

selecting Option 6, the approach used to develop the final RQs: 

o Option 1: Allowing the radionuclide RQ to remain at 

one pound; 

o Option 2: Considering radionuclides as a generic 

class of substances, without an RQ and not subject to 

CERCLA reporting requirements; 

o Option 3: Establishing a dose-equivalent level as 

the radionuclide RQ; 

o Option 4: Considering radionuclides as a class with 

a single activity level; 

o Option 5: Grouping radionuclides into categories 

with an activity level assigned to each of the 

separate categories; and 

o Option 6: Establishing an activity level RQ for 

individual radionuclides. 

2.1 OPTION 1: ALLOWING THE RADIONUCLIDE RQ TO REMAIN AT ONE POUND 

Section 102(b) of CERCLA establishes the RQ for radionuclides at one 

pound. While a one-pound RQ might be useful to ensure reporting of very large 

radionuclide releases, the Agency does not believe that this RQ level is 

appropriate to trigger timely reporting or timely field responses, if 

necessary, for releases of many radionuclides because releases of 

radionuclides that are several orders of magnitude smaller than one pound may 

represent a serious health and environmental threat. In addition, a one-pound 

RQ does not conform to commonly accepted units of measurement for 

radionuclides. Most radiation measurements in the United States are in terms 

of curies or rem, not pounds. A one-pound RQ level would, therefore, differ 

markedly from reporting requirements under other radionuclide regulations 

developed by EPA and other agencies. 

A one-pound RQ for the entire class of radionuclides would also not take 

into account the variety of hazards posed by different radionuclides. Because 

each radionuclide has a unique specific activity (i.e., a certain number of 

Radiation measurements can also be expressed in international units 

of becquerels or sieverts; however, these terms are less common in the United 

States. 
P.18 

2-2 

curies for one pound), a single one-pound RQ would relate to different numbers 

of curies -- and different radiation levels -- for each radionuclide. The 

Agency, therefore, concluded that a one-pound RQ was not sufficiently 

protective of public health and welfare and the environment. 

2.2 OPTION 2: CONSIDERING RADIONUCLIDES AS A GENERIC CLASS OF SUBSTANCES, 

WITHOUT AN RQ AND NOT SUBJECT TO CERCLA REPORTING REQUIREMENTS 

In the April 4, 1985 final rule establishing notification requirements 

and adjusting RQs for certain hazardous substances (50 FR 13456), EPA decided 

not to establish RQs for broad generic classes of organic and metallic 

compounds even though they are designated as toxic pollutants under section 

307(a) of the Clean Water Act and thus included in CERCLA's hazardous 

substance list. The reasoning for this decision, as stated in the preamble to 

that rule, was: 

Many of the generic classes of compounds encompass 

hundreds or even thousands of specific compounds. It 

would be virtually impossible for the Agency to develop a 

reportable quantity that would take into account the 

varying characteristics of all the specific compounds in 

the class (50 FR 13461) . 

Because there are over 1,500 known radionuclides, the Agency considered using 

a similar approach for radionuclides; that is, not establishing an RQ for 

radionuclides and not requiring radionuclide releases to be reported to the 

National Response Center. In considering this approach, however, the Agency 

determined that the same technical argument could not be used to support a 

decision not to establish an RQ for radionuclides. Although the term 

"radionuclides" encompasses hundreds of radioactive isotopes and countless 

chemical compounds involving these isotopes, it is. possible to set a single RQ 

in terms of dose-equivalent (rem) for the generic class of radionuclides and 

still take into account some of the unique characteristics of individual 

radionuclides. Using a set of conservative exposure assumptions, it is also 

possible to set an RQ in terms of activity levels (curies) for radionuclides 

based on a predetermined acceptable exposure level. The argument used for the 

generic classes of organic and metallic compounds, therefore, is not 

applicable entirely to radionuclides. 

The Agency also considered establishing no RQ for radionuclides based on 

the finding that existing reporting mechanisms for radionuclide releases were 

adequate and that any additional reporting pursuant to CERCLA would provide no 

additional benefit. Under this approach, even without an RQ and therefore 

without a requirement to report releases of radionuclides under CERCLA, 

radionuclides would remain listed as a hazardous substance and would be 

subject to CERCLA response and liability provisions. Elimination of an RQ for 

radionuclides would rely on existing reporting requirements of other agencies. 

This approach would minimize duplication of and conflicts with other federal 

and state reporting requirements. 

The Agency determined, however, that this option would not be 

sufficiently protective of public health and welfare and the environment. 

Less than one third of facilities that handle or produce radionuclides are 
P.19 

2-3 

licensed by the Nuclear Regulatory Commission, an Agreement State, or the 

Department of Energy. The regulation of NARM is fragmented, non-uniform, and 

incomplete. Releases of NARM generally are not subject to federal control and 

licensing, and state controls over NARM range from complete licensing programs 

to initial registration requirements. Releases from these facilities could 

go unreported if no RQ were to be established. The Agency concluded, 

therefore, that it would not be fulfilling its mandate under CERCLA if no RQ 

was established for radionuclides. 

2.3 OPTION 3: ESTABLISHING A DOSE-EQUIVALENT LEVEL AS THE RADIONUCLIDE RQ 

A dose-equivalent level is a direct measurement of the amount of 

biological damage resulting from exposure to ionizing radiation. 

Dose-equivalent is measured in terms of rem or sieverts and is equal to the 

product of the absorbed dose, in units of rads or grays, and a quality factor 

assigned to the type of radiation being emitted. 

Dose-equivalent, unlike activity, is not a measure of the emitted 

radiation, but is a method of normalizing the effectiveness of an absorbed 

dose of radiation in damaging tissue, regardless of the type of radiation. It 

also must be understood that activity is a physical phenomenon, whereas doseequivalent is a description of the biological effectiveness of a given 

exposure circumstance. Nevertheless, using standard assumptions regarding 

such factors as route and duration of exposure, quantity of intake, and 

determination of the tissues most affected, a dose-equivalent level may be 

related directly to a level of activity for particular radionuclides. 

The Agency considered establishing an RQ for radionuclides in terms of 

dose-equivalent (rem) because rem is an acceptable unit of measurement for 

radionuclide releases and, in fact, most existing reporting requirements are 

in units of rem. The principal advantage to this option is that different 

exposure scenarios (e.g., different radionuclide forms, routes of exposure, 

and age and locations of receptors) will yield a different number of rem. 

Therefore, an RQ in terms of a rem level that is deemed to be acceptable could 

be independent of the exposure scenario --it would apply to any release 

which, under existing circumstances (whatever they may be), could result in 

the specified number of rem. 

^U.S." Nuclear Regulatory Commission, Regulation of Naturally Occurring and 

Accelerator-Produced Radioactive Materials--An Update. NUREG-0976, October 1984, 

p. 1-3. 

3The gray is a unit of absorbed dose. One gray is equal to an absorbed 

dose of 1 joule/kilogram or 100 rads. The rad is a unit of absorbed dose. One 

rad is equal to an absorbed dose of 100 ergs/gram or 0.01 joule/kilogram. The 

sievert is a unit of dose-equivalent. One sievert is equal to a doseequivalent of 100 rem. Originally "Roentgen Equivalent Man," the rem is also a 

unit of dose-equivalent. The dose-equivalent in rem is numerically equal to the 

absorbed dose in rads multiplied by the quality factor (Q). Q is equal to 1 for 

X-rays, gamma rays, and beta particles; Q is equal to 10 for fast neutrons from 

fission, for example, and for protons; and Q is equal to 20 for alpha particles 

and fission fragments. 
P.20 

2-4 

There are several important disadvantages to this option, however. 

First, an RQ in terms of dose-equivalent (rem) would leave a significant 

amount of judgment to the person in charge of the facility or vessel. This 

person would have been required to estimate or judge the quantity released, 

the potential routes of exposure, the period of exposure, and the most 

vulnerable organ of the body potentially affected by the release. In essence, 

if the RQ were to be established in units of rem, the person in charge of the 

vessel or facility would be placed in a position of determining whether the 

release posed a threat to public health or welfare or the environment. CERCLA 

establishes that role for the federal government, not for the person in charge 

of the vessel or facility. 

In addition, the calculation (or estimation) of dose-equivalent is not 

straightforward. It could preclude a timely report and, therefore, a timely 

response should one be deemed appropriate. Finally, because of all the 

judgments and assumptions required to estimate dose-equivalent, the estimated 

dose-equivalent for two different releases with the same level of activity of 

the same radionuclide may vary drastically under different assumptions. This 

potential variability, even with a standardized calculation methodology, makes 

it difficult to (1) assure that the government will be notified of all 

radionuclide releases that it deems necessary; and (2) enforce an RQ in doseequivalent units. 

2.4 OPTION 4: CONSIDERING RADIONUCLIDES AS A CLASS WITH A SINGLE ACTIVITY 

LEVEL 

Because activity levels are relatively easy (compared to the estimation 

of dose-equivalents) to estimate or measure quickly during a release event 

through the use of available survey instruments, the Agency considered 

establishing an RQ for radionuclides, as a generic class, in units of curies. 

A level of activity, in units of curies (or becquerels), is a measure of the 

rate of radioactive decay and thus the amount of radiation given off by a 

substance. However, a single RQ in units of curies applicable to all 

radionuclides would not account for varying degrees of hazard posed by 

different radionuclides. Exhibit 2-1 shows the range of different 

dose-equivalent levels (reflecting relative levels of damage to the body) 

which may result from the inhalation of one microcurie of different 

radionuclides. 

While simplicity in reporting must be sought, the Agency does not believe 

that it should be accomplished by ignoring substantial differences among 

individual radionuclides. It would be extremely difficult to derive an RQ in 

terms of a single level of activity that would provide timely reporting of the 

most hazardous radionuclides while not being overly protective for others. 

2.5 OPTION 5: GROUPING RADIONUCLIDES INTO CATEGORIES WITH AN ACTIVITY LEVEL 

ASSIGNED TO EACH OF THE SEPARATE CATEGORIES 

Radionuclides may be segregated into various groups in such a way that a 

single level of activity may be an appropriate RQ for all the radionuclides 

within a given group. One RQ, which would assure timely reporting for 

releases of the most hazardous radionuclides, could be assigned to each group. 

For example, the Agency considered grouping radionuclides into "half-life 
P.21 

2-5 

EXHIBIT 2-1 

EFFECTIVE DOSE-EQUIVALENTS-*/ RESULTING FROM THE INHALATION 

OF ONE MICROCURIE OF DIFFERENT RADIONUCLIDES 

Radionuclide 

Effective dose-equivalent 

if one microcurie 

is inhaled (rem)--*/ 

Tritium (H3) 

Technetium-99 

Radium-226 

Uranium-238 

Plutonium-238 

.0001 

.07 

8 

6 

500 

--/ The effective dose-equivalent is a weighted average of committed doseequivalents for specific organs. It provides a measure of the overall (i.e., 

whole body) carcinogenic and genetic effects resulting from a radionuclide 

exposure. 

—/ The number of rem to the whole body resulting from the intake of a 

radionuclide depends on, among other factors, the particle size and solubility 

of the radionuclide involved. To facilitate comparison of the hazard levels 

associated with each of the above radionuclides, the dose-equivalent levels 

are based on each radionuclide having roughly the same solubility (a "W" 

compound or, in the case of tritium, highly soluble) and particle size (an 

activity median aerodynamic diameter of 1 fim). 

Source: Dunning, et.al., Estimates of Internal Dose-Equivalents to 22 Target 

Organs for Radionuclides Occurring in Routine Releases From Nuclear Fuel-Cycle 

Facilities. Vol. Ill, NUREG-0150, 1981. 
P.22 

2-6 

categories" with progressively higher RQs for those categories having shorter 

half lives. Another option considered was to separate radionuclides into 

groups of alpha, beta, and gamma emitters with progressively higher RQs for 

each of these categories. The RQs for non-radioactive substances have been 

established in this fashion, with different RQs for different groups of 

chemicals having similar chemical and toxicological properties. 

The Agency chose not to adopt the two methods of categorizing 

radionuclides mentioned above. The Agency believes that radionuclides grouped 

into half-life categories with progressively higher RQs for those categories 

having shorter half lives may not be protective of public health and the 

environment because radionuclides with relatively short half lives (e.g., ten 

days) could emit high energy radiation at a high rate for which the federal 

government may wish to receive notification to determine whether a response 

action is necessary. With regard to categorizing radionuclides on the basis 

of whether they are primarily alpha, beta, or gamma emitters, the actual 

threat to public health or welfare or the environment is often less dependent 

on the type of emission than on the energy of the radiation (i.e., a high 

energy beta particle might be more harmful than a low energy alpha particle). 

The Agency did not select this option because it could not determine 

appropriate groups or categories for radionuclides prior to examining each 

individual radionuclide and estimating the potential effect of a release of 

each. 

2.6 OPTION 6: ESTABLISHING AN ACTIVITY LEVEL RQ FOR INDIVIDUAL RADIONUCLIDES 

The Agency ultimately decided to issue RQ adjustments for individual 

radionuclides based on levels of activity. There are several advantages to 

basing radionuclide RQs on activity levels. For example, a level of 

radioactivity is much easier to estimate than a dose-equivalent. The Agency 

believes that setting RQs in terms of activity, therefore, would provide more 

timely reporting than an RQ expressed in terms of dose-equivalent. 

A second advantage of using activity levels is that establishing RQs for 

radionuclides individually would allow consideration of individual 

radionuclide characteristics including the type and strength of ionizing 

radiation produced during a release. An RQ in terms of dose-equivalent (rem) 

also would (by definition) have considered type and strength of ionizing 

radiation", but would have left much greater judgment to the person in charge 

of the vessel or facility. Activity level RQs (curies) also consider each 

radionuclide individually, but minimize judgments by the person in charge of 

the vessel or facility. The option to establish RQs in terms of curies, 

therefore, was considered advantageous. 

The Agency recognizes that the nuclide-specific RQ approach also has 

disadvantages. Primarily, unlike a dose-equivalent value, a level of activity 

by itself does not necessarily reflect a level of danger to human health. A 

release of an RQ, therefore, does not necessarily mean that there has been or 

will be any harm. As is presently the case for RQs for non-radioactive 

substances, a case-by-case evaluation will be necessary to estimate the human 

health and welfare and environmental hazards associated with a radionuclide 

release, and to determine if a federal response is warranted. 
P.23 

CHAPTER 3 

MAJOR ISSUES ASSOCIATED WITH THE SELECTED RQ ADJUSTMENT METHODOLOGY 

Based on the advantages and disadvantages of the various RQ adjustment 

options discussed in Chapter 2 of this report, EPA chose to establish a 

specific curie level for individual radionuclides as the adjusted radionuclide 

RQs. To determine the appropriate RQ for each radionuclide, EPA estimated the 

quantity of radionuclides that, if released under a conservative set of 

exposure conditions, could result in an individual receiving an effective 

dose-equivalent1 of 500 millirem. The specific methodology used to estimate 

this quantity for each radionuclide is described in detail in Chapter 4 of 

this report. 

EPA published a Notice of Proposed Rulemaking (NPRM) to adjust the 

statutory RQ for radionuclides on March 16, 1987 (52 FR 8172). The 

methodology used to determine the RQ adjustments proposed in the NPRM was 

documented in detail in a supporting Technical Background Document (TBD).2 

EPA received numerous comments on the NPRM concerning the technical approach 

used to calculate the proposed RQs. Many of the comments questioned specific 

assumptions made in the exposure scenarios used to calculate RQs and, in 

response to these comments, the Agency analyzed how the proposed RQs would 

change under varying sets of assumptions. The methods and results of this 

additional analysis are documented in a Supplementary Technical Background 

Document. Based on the comments received and further analysis, several 

changes in the proposed RQ adjustment methodology were made in order to 

calculate final RQs. 

This chapter summarizes the major technical issues raised in comments.on 

the NPRM and TBD, and highlights changes made in the RQ adjustment methodology 

in response to these comments. Where applicable, the Agency's rationale for 

not changing the methodology in response to comments also is summarized. The 

chapter is divided into six sections, with each section describing a separate 

issue and what, if any, changes have been made in the RQ adjustment 

methodology in order to resolve the issue. 

•'-The effective dose-equivalent is a weighted average of committed doseequivalents for specific organs, with the weights determined from risk factors 

associated" with the respective organs. It provides a measure of the overall 

(i.e., total body) carcinogenic and genetic risk resulting from a radionuclide 

exposure. 

^U.S. Environmental Protection Agency, Technical Background Document to 

Support Proposed Rulemaking Pursuant to Section 102 of the Comprehensive 

Environmental Response. Compensation, and Liability Act: Radionuclides. Office 

of Emergency and Remedial Response, Emergency Response Division, December 1986. 

JU.S. Environmental Protection Agency, Methods and Results for 

Calculations of Radionuclide Reportable Quantities Under Varying Sets of 

Conditions. Office of Emergency and Remedial Response, Emergency Response 

Division, June 18, 1987. 
P.24 

3-2 

3.1 DEPARTURE FROM THE METHODOLOGY FOR ADJUSTING RQs OF POTENTIAL CARCINOGENS 

Although radionuclides are recognized as potential carcinogens, EPA chose 

not to use the existing RQ adjustment methodology for potential carcinogens to 

determine proposed RQs for radionuclides. This choice has been affirmed in 

the determination of final radionuclides RQs. The reasons for this departure 

are outlined below, following a brief description of the potential carcinogen 

methodology. 

EPA's methodology for adjusting the RQs of potential carcinogens was 

published in the Federal Register on March 16, 1987 (52 FR 8140). Briefly, 

this methodology consists of two general steps. First, potential carcinogens 

are assigned to "high," "medium," or "low" hazard categories based on their 

carcinogenic potency and the weight-of-evidence indicating that they are in 

fact human carcinogens. In the next step, RQs are assigned to each potential 

carcinogen based on their relative ranking. Potential carcinogens in the high 

category are assigned an RQ of one pound, those in the medium category are 

assigned a 10-pound RQ, and those in the low category are assigned an RQ of 

100 pounds. 

Direct application of the potential carcinogen methodology for the 

adjustment of radionuclide RQs would not be appropriate for several reasons. 

First, because all radionuclides produce ionizing radiation and ionizing 

radiation is known to be carcinogenic to humans, radionuclides would be 

assigned either a one- or 10-pound RQ based on the potential carcinogen 

ranking system. Neither of these levels are appropriate for radionuclide RQs 

because as little as one-billionth of a pound of certain radionuclides might 

pose a hazard worthy of a report. Second, the RQs that would be established 

if the potential carcinogen methodology was used (i.e., one or 10 pounds) 

would vary by only one order of magnitude, while the hazards associated with 

radionuclides can differ by many orders of magnitude. Finally, establishing 

RQs in mass units such as pounds is inappropriate because most radiation 

measurements and standards in the U.S. are established in terms of curies or 

rem, not pounds. 

Even modification of the potential carcinogen methodology would not 

address the crucial question of the appropriate scales for radionuclide RQs. 

The potential carcinogen methodology would be useful to rank radionuclides 

relative to each other, but not to assign a specific RQ to each radionuclide. 

Therefore", EPA has developed an entirely different methodology for adjusting 

radionuclide RQs, one that models a series of exposure scenarios that link a 

quantity of radionuclide released with an internationally accepted doseequivalent limit of 500 millirem for the general public. 

3.2 INCORPORATION OF RADIOACTIVE DECAY 

In the exposure pathway modeling done to calculate proposed radionuclide 

RQs, EPA purposefully ignored the effects of radioactive decay for the sake of 

conservatism and simplicity. Many commenters expressed concern that this 

approach led to RQs for certain short-lived radionuclides that were 

unnecessarily low. Based on these comments and recognizing that radioactive 

decay is an intrinsic property of all radionuclides, EPA has decided to 

incorporate the effects of radioactive decay in the exposure pathway models 
3-3 

used to develop final RQs. As would be expected, this change resulted in a 

general shift toward higher RQs. 

For the purpose of this analysis, the total period of time in the 

hypothetical release and exposure scenarios can be divided into three 

segments: (1) the time period over which the release occurs; (2) the time it 

takes for the radionuclide to travel from the point of release to the point of 

exposure; and (3) the period of exposure. Radioactive decay over these time 

periods is taken into account differently in the different exposure pathway 

models, as described in Chapter 4 and Appendices A through D of this report. 

3.3 ASSUMED DISTANCE BETWEEN THE POINT OF RELEASE AND THE POINT OF EXPOSURE 

As described in detail in Chapter 4, the radionuclide RQs were determined 

by examining a hypothetical release and exposure scenario in which a 

radionuclide is released into the environment and migrates to an exposure 

point. In determining proposed RQs, the assumed distance between the point of 

release and point of exposure in all scenarios was 30 meters. EPA received 

conflicting comments on this assumed distance; some arguing that it is too 

close because the distance to unrestricted areas at many facilities that 

handle radionuclides is far greater than 30 meters, and others arguing that, it 

is too far because it is possible for individuals to come within closer 

distances (e.g., 1 meter) of a radionuclide release. 

EPA has retained the assumed distance of 30 meters in all exposure 

scenarios analyzed for the development of final RQs. It is recognized that no 

one, single distance would be representative of all possible release scenarios 

involving radionuclides; however, EPA also believes that it would be 

unnecessarily complicated (thus jeopordizing timely reporting) to have 

multiple RQs for different distances, especially when it is realized that the 

actual circumstances of a release (including the distance to exposure points) 

will be evaluated in deciding whether to take a field response once a report 

is made. Therefore, recognizing its inherent limitations, EPA has decided to 

base all the radionuclide RQ calculations on just one distance. 

There are several compelling reasons to use 30 meters in the calculation 

of RQs. First, this distance is in the range of, and generally is consistent 

with, recommended isolation distances in the event of hazardous substance 

spills. The Department of Transportation (DOT) Emergency Response Guidebook 

recommends that unnecessary people be kept at least 45 meters upwind from 

releases of three categories of nuclear material. For 11 other categories of 

nuclear material, however, the Guidebook does not specify a single evacuation 

or isolation distance; it simply recommends that unnecessary people be kept 

"away," that the hazard area be isolated, and that entry to the area be 

denied. Furthermore, for small leaks of hazardous chemicals (not 

radionuclides), the recommended initial isolation distances range from 9 to 

180 meters, and for large spills, the recommended isolation distances range 

from 20 to 380 meters. Approximately 44 percent of the initial isolation 

distances recommended for releases of hazardous chemicals is in the 0-30 meter 

U.S. Department of Transportation, 1984 Emergency Response Guidebook. 

Guidebook for Hazardous Materials Incidents. DOT P 5800-3, 1984. 
3-4 

range. Therefore, 30 meters appears to be an isolation distance that 

generally would be familiar based on published recommendations, and one that 

might actually be used in the event of a radioactive material release. 

Second, although many facilities are separated from unrestricted areas by 

more than 30 meters, certain categories of facilities that can release 

radionuclides often do not have such a large buffer area surrounding them. 

For example, medical facilities and research laboratories may allow members of 

the general public within 30 meters of possible release points. 

Finally, EPA believes that a distance of 30 meters is reasonably 

conservative and that using this distance to determine RQs would assure timely 

reporting for most conceivable release situations. Using a shorter distance, 

such as 1 meter, would result in RQs that are unreasonably low for most 

release situations, leading to unnecessary reports and burdens. Long-term 

exposures at less than 30 meters are believed mostly to be representative of 

occupational exposures within the workplace, which RQs are not intended to 

address. Moreover, it is recognized that exposure distances of less than 30 

meters could occur in scenarios involving a lost radioactive source, but 

reports of lost sources generally would not initiate a response action 

regardless of the RQ because the location of the source would be unknown. 

3.4 ASSUMED CONFIGURATION OF RADIONUCLIDE RELEASE 

As part of the release and exposure scenarios examined for the 

determination of proposed RQs, EPA assumed that radionuclides are released 

into the environment from a point source. Many commenters pointed out that 

radionuclides frequently are released from areal sources (e.g., radon releases 

from coal ash piles or open pit mines) and that the proposed RQs were 

unnecessarily low for this type of release. 

Although EPA recognizes that a point source release model is not 

applicable for areal sources, the point source release configuration has been 

retained in all exposure scenarios used to determine final RQs. The rationale 

for this decision is basically the same as that presented above for the 

selection of the 30-meter distance in the exposure scenario. Namely, EPA 

believes that it would be best to use a single release configuration to 

determine RQs (multiple RQs for different release configurations could cause 

confusion and untimely reporting), and the single best release configuration 

to assume is a point source because it is conservative (i.e., it is more 

likely to yield RQs that will assure timely reporting than an areal source). 

By assuming a point source to determine RQs, however, EPA recognizes that 

there may be many areal sources that release more than an RQ of radionuclides 

each day. It is possible that the government would never respond to a report 

of some of these releases. Therefore, in response to requests from the 

public, EPA plans to evaluate available release data to determine if certain 

releases can be administratively exempted from the RQ reporting requirements 

to help eliminate unnecessary reporting burdens. In response to public 

comments on the NPRM, EPA already has examined and prepared a separate 
P.27 

3-5 

report5 on the radiological hazards associated with coal and ash at coal-fired 

boiler sites. The purpose of this analysis was to investigate whether a 

sufficient technical basis exists for administratively exempting releases of 

radionuclides in coal and coal ash from the RQ reporting requirements. 

3.5 MODELING OF POTENTIAL EXPOSURES THROUGH THE INGESTION OF CONTAMINATED 

VEGETABLES 

In determining the proposed RQs, EPA considered an exposure scenario in 

which an individual ingests vegetables contaminated by the airborne deposition 

of radionuclides. This scenario was not used as a basis for the proposed RQs, 

however, because it was found to be generally a less critical exposure pathway 

than the ingestion of contaminated water under the set of conditions assumed 

(i.e., for the majority of radionuclides, lower RQs were calculated for 

scenarios involving the consumption of contaminated water than for scenarios 

involving the consumption of contaminated vegetables). The ingestion of 

contaminated vegetables, however, was considered more fully in the development 

of final RQs for the reasons stated below. 

Decisions to include the effects of radioactive decay in the exposure 

pathway models and to use a different, more conservative model for calculating 

the factor representing the transfer of radionuclides from air to vegetation 

tend to exaggerate the importance of the vegetable ingestion pathway relative 

to other pathways. Appendix C of the Technical Background Document supporting 

the NPRM describes the two models considered for estimating deposition of 

radionuclides. One of the models is presented by the Nuclear Regulatory 

Commission in Regulatory Guide 1.1096 and the other is a model presented by 

the National Council on Radiation Protection and Measurements (NCRP).7 The 

proposed RQs were based on the Nuclear Regulatory Commission model, which was 

subsequently determined to be inappropriate for the release configurations and 

distances considered for the development of RQs. The NCRP model, which is 

very conservative when coupled with the atmospheric dispersion factor 

considered, was determined to be the most straightforward method for 

determining RQs for the vegetable ingestion pathway. See Section 4.4 and 

Appendix C of this report for more detail on these two models and the reasons 

for ultimately selecting the NCRP model. 

5 U.S. Environmental Protection Agency, Technical Background Supplement 

in Support of Rulemaking Adjustment Activities for Reportable Quantities (RQs) 

of Radionuclides. Office of Radiation Programs, February 1989. 

6U.S. Nuclear Regulatory Commission, Calculation of Annual Doses to Man 

from Routine Releases of Reactor Effluents for the Purpose of Evaluating 

Compliance with 10 CFR Part 50. Appendix I. Regulatory Guide 1.109, Revision 

1, October 1987. 

7National Council on Radiation Protection and Measurements, Screening 

Techniques for Determining Compliance with Environmental Standards: Releases 

of Radionuclides to the Atmosphere. NCRP Commentary No. 3, 1986. 
P.28 

3-6 

3.6 ADDITIONAL EXPOSURE PATHWAY MODELS 

In the development of final RQs, the Agency considered four potential 

exposure pathways more fully than it did in the development of proposed RQs. 

These pathways are the ingestion of contaminated surface water, the ingestion 

of vegetables contaminated by radionuclide-bearing irrigation water, the 

ingestion of contaminated milk, and direct exposure to neutrons. 

As described in the TBD supporting the NPRM, potential exposures through 

the ingestion of contaminated surface water were considered qualitatively, but 

an equation for the calculation of RQs based on this pathway was not 

developed. It was recognized that, as long as radioactive decay was not taken 

into account (as was the case for the proposed RQs), the ingestion of surface 

water generally would be a less critical exposure pathway than the ingestion 

of ground water because surface water generally would provide for much greater 

dilution. By incorporating radioactive decay into the calculation of final 

RQs, however, the relative importance of the surface water pathway was 

increased significantly because of the decay that can occur over the long 

transport times in ground water. Accordingly, the potential ingestion of 

contaminated surface water was considered more rigorously in the development 

of final RQs (see Section 4.3 and Appendix B of this report). 

Similarly, to determine the proposed RQs, EPA considered potential 

exposures via other ingestion pathways (e.g., meat and milk) qualitatively, 

suggesting that, under the set of exposure conditions assumed, these other 

ingestion pathways would be less critical than either the ingestion of water 

or the ingestion of vegetables. EPA recognizes that these other ingestion 

routes actually could be more critical depending on the conditions of a 

release and, based on comments received on the NPRM, the ingestion of 

vegetables contaminated by irrigation and the ingestion of meat and milk was 

analyzed more fully in the development of final RQs. See Section 4.4 and 

Appendix C of this report for a discussion of the methods and results of this 

analysis. 

Twenty-four radionuclides decay, at least part of the time, by 

spontaneous fission and emit neutrons. Neutrons can present a significant 

external hazard and, therefore, direct exposure to neutrons was taken into 

account in the determination of final RQs (see Section 4.5 and Appendix D of 

this report for a discussion of the methods and result of this analysis of 

neutrons). 
P.29 

CHAPTER 4 

METHODOLOGY FOR RQ ADJUSTMENTS 

This chapter describes the Agency's methodology for adjusting the RQ for 

radionuclides. The chapter is divided into seven main sections. Section 4.1 

provides an overview of the methodology, outlining the basic rationale and 

general steps taken. The sections that follow describe the steps outlined in 

Section 4.1 in more detail. Sections 4.2, 4.3, 4.4, and 4.5 describe the 

methods used to determine RQs based on inhalation, ingestion of water, 

ingestion of food, and direct exposure, respectively. In Section 4.6, the 

assignment of radionuclides to RQ groups is described and, finally, Section 

4.7 outlines the basis for reporting requirements for mixtures. 

4.1 OVERVIEW OF THE METHODOLOGY 

In simplest terms, the RQs were determined by estimating the quantity of 

a radionuclide that, if released into the environment under an assumed set of 

conditions, could result in an individual receiving a specified effective 

dose-equivalent. To estimate this quantity for each radionuclide, a series of 

hypothetical (but conservative) exposure scenarios were analyzed to link a 

quantity released with an accepted dose level. 

This process begins with the Annual Limits of Intake (ALIs) published for 

757 radionuclides in ICRP's Publication 30. ALIs are the quantity of 

radionuclides (in becquerels) that, if taken in by "Reference Man,"^ would 

result in either (1) a committed effective dose-equivalentJ of 5 rem to the 

whole body (stochastic ALI), or (2) a committed dose-equivalent^ of 50 rem to 

any organ or tissue (non-stochastic ALI). In the proposed revision to 10 CFR 

Part 20, the Nuclear Regulatory Commission proposes the adoption of ALIs 

because: "the revision improves radiation protection standards by reflecting 

developments in the principles that underlie radiation protection and advances 

in related sciences that have occurred since the promulgation of 10 CFR Part 

International Commission on Radiological Protection, Annals of the ICRP: 

Limits for Intakes of Radi onucl.id.6s by Woirksrs, ICRP Publication 30, Pa._rt 2, 

1980. 

rt 

^Reference man is a hypothetical individual possessing "average" 

characteristics of humans (such as body weight, dietary intake, and inhalation 

rate) to "serve as a common biological basis for calculating ALI and other values. 

•3 

An effective dose-equivalent is a weighted average of committed doseequivalents for specific organs, with the weights determined from risk factors 

associated with the respective organs. It provides a measure of the overall 

(i.e., total body) carcinogenic and genetic risk resulting from a radionuclide 

exposure. The term "committed dose-equivalent" means that this is the dose 

that will accrue from one year of intake of radionuclides during the remaining 

lifetime (50 years) of the individual. 

^The dose-equivalent referred to here is the same as that described in 

footnote 3 above, except that it is the dose to a single organ or tissue rather 

than an "effective" dose to the total body. 
4-2 

20 nearly 30 years ago" (50 FR 1092, January 9, 1986). In short, the proposed 

ALIs are intake limits designed to limit the risk of health damage. 

EPA used the ALIs from ICRP 30 to determine RQs by estimating the 

quantity of radionuclides that, if released, could result in the intake of 

one-tenth of an ALI. The ALIs were divided by 10 to adjust the dose that they 

are based on (an effective dose-equivalent of 5 rem for most radionuclides 

and, for a minority of radionuclides, a dose-equivalent of 50 rem to the 

critical organ) to an effective dose-equivalent of 0.5 rem (500 millirem). A 

whole-body dose-equivalent of 500 millirem is recommended by the Federal 

Radiation Protection Guidance as an upper bound on exposure to individual 

members of the general public. EPA believes that this dose-equivalent level 

is appropriate for the purpose of calculating RQs; RQs based on 500 millirem 

should be sufficiently low to assure timely reporting in most circumstances 

but not so low as to create unnecessary reporting. As discussed below, 

numerous conservative assumptions were made in the calculation of RQs so that 

the release of an RQ will probably result in whole body doses less than 500 

millirem. 

Hypothetical releases and exposures were analyzed for four different 

routes of exposure: inhalation, ingestion of water, ingestion of vegetables, 

and direct exposure. For each exposure pathway, a "release value" was 

calculated for the 757 radionuclides for which ALIs have been published. The 

release values represent a quantity of radionuclides (in curies) that, if 

released under the conditions assumed, could result in a whole-body doseequivalent of 500 millirem via each of the exposure pathways. These release 

values were calculated using simple and conservative models that define a 

hypothetical scenario in which: (1) a radionuclide is assumed to be released 

into an environmental medium; (2) the radionuclide is transported from the 

point of release to the point of exposure and diluted along the way; and (3) a 

person is exposed to (i.e., inhales, ingests, or is exposed to direct 

radiation from) the released radionuclide over a certain length of time. In 

these scenarios, many properties intrinsic to the radionuclides and many 

environmental variables are considered, leading to different release values 

for the different exposure pathways. 

For each radionuclide, the release values calculated for the different 

exposure pathways were compared to one another and the lowest was selected. 

This lowest release value was then rounded down to the nearest decade to 

determine" the RQ for that radionuclide. For all radionuclides that do not 

have published ALI values, a single RQ was selected for all of them based on 

the distribution of RQs calculated as outlined above for the 757 radionuclides 

that do have ALIs. 

4.2 RELEASE VALUES FOR THE INHALATION PATHWAY 

Inhalation release values are in units of curies and represent the 

activity level of each radionuclide that, if released under a set of 

conservative circumstances, could result in an exposed individual inhaling 
P.31 

4-3 

one-tenth of an ALI. The Agency developed the following mathematical 

expression to derive release values based on exposure through inhalation: 

(1) Inhalation Release Value = ALI/((10)*(R)*(X/Q)*(BR)*(lxl06)) 

where: 

ALI = Annual Limit of Intake for inhalation (microcuries); 

10 = Factor to adjust the dose-equivalent on which the ALI is 

based (dimensionless); 

R = Airborne release fraction (dimensionless); 

-13 X/Q = Atmospheric relative concentration value (8.4 x 10 

day/cubic cm); 

BR = Breathing rate (2.3 x 10 cubic cm/day); and 

1 x 10 = Conversion factor between microcuries and curies. 

The inhalation ALIs used in the calculations are taken from the ICRP's 

Publication 30 (after conversion from becquerels to curies). Where more than 

one inhalation ALI was available for a particular radionuclide, the lowest 

value was used for the calculations. This approach assures that release of 

the radionuclide in its most hazardous chemical form is taken into 

consideration. The inhalation ALIs are derived for workers in nuclear 

facilities and are 10 times those recommended for adult members of the general 

public. To adjust the Commission's ALIs to reflect the more protective level 

of exposure to the general public, the ALIs are divided by 10. 

The release fraction, R, reflects the fraction of the radionuclide 

release that could become airborne and be of respirable size (10 microns in 

diameter or less). The Nuclear Regulatory Commission has developed methods 

for estimating release fractions for radionuclides under accident conditions. 

A summary of these methods and a table of release fractions for those 

individual radionuclides with specific RQs can be found in Appendix A of this 

report. 

The atmospheric relative concentration value (X/Q) used in the 

calculations, 8.4 x 10 day/cubic cm, corresponds to the relative 

concentration, at ground level, 30 meters downwind from a ground-level pointsource release under neutral (Class D) meteorological conditions. A 

-"For most radionuclides, the intake of one-tenth of an ALI will cause an 

effective dose-equivalent of 500 millirem. For a few radionuclides, the intake 

of one-tenth of an ALI will result in a dose-equivalent of 5 rem to the most 

exposed organ. 

°McGuire, S.A., A Regulatory Analysis on Emergency Preparedness for Fuel 

Cycle and Other Radioactive Materials Licenses. NUREG-1140, U.S. Nuclear 

Regulatory Commission. 
P.32 

4-4 

ground-level release under Class D meteorological conditions leads to higher 

ground-level concentrations than would be the case for a release under more 

turbulent conditions. By using the ground-level concentration, the derived 

release values are lower than would be the case if the Agency had used an 

above-ground concentration. Similarly, release values based on a pointsource release at ground level are lower than would be calculated if an areal 

source had been assumed or if an above-ground source (e.g., a smokestack) had 

been assumed. Thus, the proposed RQs are based on a more protective release 

scenario. 

The Agency has chosen 30 meters as a reasonably conservative distance 

between the point of release and point of exposure (see Section 3.3 of this 

report). At fixed facilities, the distance to unrestricted areas is likely to 

be greater than 30 meters; therefore, 30 meters will result in a conservative 

estimate for exposure. The Agency derived the value of X/Q for distances less 

than 100 meters based on the dispersivity data presented in The Workbook of 

Atmospheric Dispersion Estimates.' The X/Q values presented in the Workbook 

do not include data for distances less than 100 meters; therefore 

extrapolation is necessary. Although the extrapolation from 100 meters to 30 

meters may not be totally accurate, a more preferred method of determining a 

value for X/Q at this distance could not be identified. The Agency believes 

its evaluation of exposure via inhalation is conservative, and that the error 

introduced by the extrapolation to 30 meters is not detrimental given the 

purpose of RQs. A further explanation of atmospheric relative concentration 

values and their derivation can be found in Appendix A of this report and in 

the Workbook on Atmospheric Dispersion Estimates. 

The inhalation of toxic substances depends in an obvious manner on the 

breathing rate of individuals. For purposes of the release value 

calculations, the breathing rate of "Reference Man" is assumed to be 2.3 x 10 

cubic centimeters per day. 

The expression shown in Equation (1) for determining the release value 

for the inhalation pathway can be simplified by substituting the following 

values into the equation: 

o (X/Q) = 8.4 x 10"13; and 

o BR = 2.3 x 107. 

By multipling the numbers in the denominator, Equation (1) simplifies to: 

(2) Inhalation Release Value = ALI (inhalation)/((193.2)*(R)) 

For each of the individual radionuclides for which an ALI is available, the 

release values calculated for the inhalation pathway are presented in Appendix 

'Turner, D. Bruce, Workbook of Atmospheric Dispersion Estimates. EPA Office 

of Air Programs, 1970. 

Till, J.E., Meyer, H.R. (Editors), Radiological Assessment. A Textbook on 

Environmental Analysis. NUREG/CR-3332, U.S. Nuclear Regulatory Commission, 1983. 
P.33 

4-5 

E of this report. As noted in the appendix, the inhalation model was not used 

for noble gases other than radon (e.g., argon, krypton, and xenon). According 

to ICRP Publication 30, the effects of inhaling a noble gas are negligible 

compared to the effects of external irradiation from a person being submerged 

in a cloud of these radionuclides. Thus, a separate model described in 

Section 4.5 was used to determine the direct exposure release value for noble 

gases. Inhalation of radon was considered because the critical health effect 

associated with exposure to radon is caused by inhalation of radon's shortlived decay products. 

It is important to clarify that Equations (1) and (2) ignore the effects 

of radioactive decay. This is because the inhalation pathway model considers 

exposure to an airborne plume of radionuclides. In this situation, a shortlived radionuclide could undergo significant decay if the release and exposure 

periods were a full day, but decay would be much less if a time period of 

several minutes was considered. Because it was not possible to establish 

exact bounds on the range of release and exposure periods, the Agency assumed 

conservatively that no decay occurs over these periods. EPA also ignored 

decay over the period of radionuclide transport to the point of inhalation. 

This approach was adopted because decay during airborne transport to a 

receptor just 30 meters away would be negligible for most radionuclides. 

4.3 RELEASE VALUES FOR THE INGESTION OF WATER 

EPA calculated release values for the ingestion of contaminated ground 

water and the ingestion of contaminated surface water. The models used to 

calculate these release values are summarized in this section and documented 

in detail in Appendix B of this report. 

For the ingestion of contaminated surface water, EPA calculated release 

values for a scenario in which: (1) a radionuclide is released from a point 

source into a small river; (2) the radionuclide mixes completely and 

instantaneously in the water column but does not settle to the bottom or 

decay; and (3) a person draws water from a point 30 meters downstream and 

drinks the water directly over the period of time that it takes the 

contamination to pass. Radioactive decay over the time it takes for the 

radionuclide to travel to the point of exposure was ignored because this time 

period would be short (probably around a minute or less), and decay over this 

period would be negligible for most radionuclides. Decay over the periods of 

release and exposure also was ignored because these periods could not be 

defined; they could be very short, such that insignificant decay would occur, 

or they could be very long, as would be the case if an individual stored a 

large quantity of water withdrawn from the river and consumed the water over 

an extended period. 

Although the release values calculated for the surface water ingestion 

pathway were sometimes lower than those calculated for the ingestion of ground 

water, the surface water release values were never the lowest when compared to 

the release values calculated for the other exposure pathways. As a result, 

none of the RQs calculated for the 757 specific radionuclides are based on the 

surface water ingestion pathway. By comparison, however, the release values 

calculated for the ground-water ingestion pathway were the lowest ones (and 

hence serve as the basis for RQs) for several radionuclides. Therefore, 
P.34 

4-6 

because the ground-water ingestion pathway affects some of the RQs while the 

surface water ingestion pathway does not, the Agency chose to use only the 

ground-water ingestion pathway in the development of final RQs. 

The method that the Agency has adopted for the calculation of release 

values based on consumption of contaminated ground water is presented in 

Equation (3) below: 

(3) Drinking Water Release Value = ALI/((10)*(DF)*(CT)*(WC)*(1 x IO6)) 

where: 

ALI = Annual limit of intake for ingestion (microcuries); 

10 -= Factor to adjust the dose-equivalent on which the ALI is 

based (dimensionless); 

DF = Dilution factor (liter ); 

CT = Contact time (days); 

WC = Water consumption of "Reference Man" (2 liters/day); and 

1x10 = Conversion factor between microcuries and curies. 

The ingestion ALIs used in the calculations are taken from ICRP's 

Publication 30 (after conversion from becquerels to curies). Where more than 

one ingestion ALI was available for a particular radionuclide, the lowest ALI 

was used for the calculations. The factor 10 converts the 5 rem annual 

occupational dose limit to the 500 millirem (0.5 rem) annual limit for members 

of the general public, as discussed for the inhalation pathway. 

The dilution factor (DF) is derived by considering the maximum 

concentration in a contaminant plume 30 meters downgradient from a point 

source release, as calculated by use of standard equations modeling 

ground-water transport. The maximum concentration is assumed to be uniformly 

distributed throughout the plume. Thirty meters is chosen for consistency 

with the atmospheric model and leads to higher concentrations and lower 

release values than would be the case for a greater distance. 

The Agency considered two dilution models during the RQ development 

process: a simple dilution model and an advection-dispersion model. The 

simple dilution model relies on the estimate that the practical need for water 

"This is a conservative approximation because concentrations are ususally 

distributed in a gaussian fashion within a plume, with smaller concentrations 

toward the edges of the plume and higher concentrations near the plume's 

center line. 
P.35 

4-7 

of a single person living in a rural area is 7,700 cubic meters per year. 

This represents a dilution factor of 1.3 x 10 per liter. The model assumes 

the flow rate of the aquifer is sufficiently slow that the contact time is an 

entire year (365 days) and the entire quantity released is pumped from the 

well over a period of one year. 

Use of the advection-dispersion model for determination of radionuclide 

concentration in drinking water relies on estimates of longitudinal and 

transverse coefficients of dispersion, bulk density of the aquifer, sorption 

coefficients for individual radionuclides, and aquifer flow rate. The Agency 

believes that, for the purpose of developing RQs, the advection-dispersion 

model is more appropriate than the simple dilution model. The simple dilution 

model assumes that all of the release will be pumped from the well and all of 

the contaminated water will be consumed by an individual. Although the simple 

dilution model appears appropriate for determining concentration levels for 

purposes of risk assessment, the advection-dispersion model is based on the 

somewhat less conservative but more likely assumption that only a fraction of 

the release will be pumped from the well and consumed by an individual. The 

Agency, therefore, based its drinking water exposure calculations on the 

advection-dispersion model. 

The Agency also considered use of several other ground-water models used 

by EPA's Office of Solid Waste to support analyses under the Resource 

Conservation and Recovery Act (RCRA). The equations used in the RCRA models 

are similar to the equations used in the advection-dispersion model; however, 

certain parameters used in the equations in the RCRA models are much more 

conservative than those used for purposes of RQ adjustment in the 

advection-dispersion model. The Agency believes that the values used as 

inputs to the advection-dispersion model are reasonably conservative and 

appropriate for the calculation of RQs. Further discussion of the 

advection-dispersion model, the simple dilution model, and the four RCRA 

models can be found in Appendix B of this report. 

The ground-water advection-dispersion modeling equations utilize a 

retardation factor, which accounts for the extent to which a radionuclide is 

retarded relative to the transporting water mass. Retardation factors for 

each radionuclide differ because different radionuclides are adsorbed 

differently onto the sand or soil in an aquifer. Because of their chemical 

nature, some radionuclides are adsorbed only weakly or not at all (e.g., 

technetium), while others are adsorbed strongly (e.g., cesium). The 

retardation factor used in the model takes into account the soil bulk density, 

iUThe Nuclear Regulatory Commission uses the simple dilution model for 

the purposes of determining allowable onsite disposal concentrations for 

radioactive waste. Oztunali, 0.1., Roles, G.W., De Minimis Waste Impacts 

Analysis Methodology. NUREG/CR-3585, February 1984. While water supplies in 

suburban or urban areas may be from ground water, the ground water is likely 

to be pumped through several high-capacity wells and then distributed through 

several interconnecting pipes to individual homes. This type of system will 

result in much greater dilution than a simple rural system where water is 

obtained from a backyard well and taken directly to a tap. 
4-8 

porosity, and the sorption coefficient, K . A table of sorption coefficients 

used in the model can be found in Appendix B. When the sorption coefficient 

is equal to zero, the retardation factor, R , is equal to one; that is, there 

is no retardation. When the sorption coefficient is greater than zero, the 

retardation factor is greater than one and nuclide retardation has occurred. 

The dilution factor used in Equation (3) is related directly to the sorption 

coefficient. The greater the sorption coefficient, the greater is the nuclide 

retardation in the aquifer, and the greater is the dilution factor. 

The retardation factor also affects the estimation of the contact time, 

the total time a contaminant plume will be in contact with an affected well. 

If the retardation factor is equal to one, the advection-dispersion model 

assumes that the contamination is moving at the same velocity as the water in 

the aquifer (i.e., no retardation occurs), and the well is in contact with the 

contamination for nine days. If the retardation factor is greater than one, 

the contamination is being retarded and is moving at a slower rate than the 

water in the aquifer. The contact time, therefore, will be longer than nine 

days. Appendix B describes further the relationship between the retardation 

factors, dilution factors, and contact times for different radionuclides. 

In calculating the drinking water release values, when the sorption 

coefficient is greater than or equal to 4 for a particular radionuclide, the 

contact time is assumed to be 365 days. In reality, it could take 

significantly longer than 365 days for the contaminant plume to pass the well 

head, but because ALIs reflect annual intake levels, the contact time in the 

advection-dispersion model is constrained not to exceed 365 days. The 

dilution factor, however, also will reflect the sorption coefficient; the 

dilution factor is very large when the sorption coefficient is significantly 

above 4. 

In the model used to calculate release values for the ingestion of ground 

water, the release is assumed conservatively to be instantaneous to the 

saturated zone such that no decay over the period of release could occur. 

Equation (3), however, does consider decay over the period of transport and 

period of ingestion. For the period of transport, an exponential decay term 

is incorporated in the calculation of the dilution factor (see Appendix B). 

To consider decay over the period of ingestion, it is recognized that an 

individual would ingest smaller quantities of radioactivity over time. 

Accordingly, decay over the period of exposure is taken into account using the 

following" integrated exponential equation involving the contact time: 

(4) 1 - exp (-Xd) 

where: 

X = 0.693/t]/2, where tw2

 = radionuclide half-life in days; and 

CT = contact time, ranging anywhere from 9 days when Rd = 1 to up to 

365 days when Rd > 1. 

Release Values calculated for the ingestion of water are presented in 

Appendix E. Again, all of the water ingestion release values in the exhibit 

are for the ingestion of ground water, because the surface water release 
P.37 

4-9 

values are never the most limiting (i.e., never affect the RQs) for any 

radionuclide. The release values noted in Appendix E as being "very large" 

are for radionuclides that have a large retardation factor and relatively 

short half-life. For these nuclides, the time of travel to a well 30 meters 

away is sufficiently long that much of the nuclide is lost due to radioactive 

decay. While release values were not calculated in these cases, it is 

recognized that they would be "very large" relative to the release values for 

the other pathways and, therefore, would not serve as the basis for RQs. 

4.4 RELEASE VALUES FOR THE INGESTION OF FOOD 

EPA considered a variety of exposure scenarios involving the ingestion of 

contaminated food. The scenarios analyzed were for: 

o the ingestion of vegetables contaminated by the 

airborne deposition of radionuclides; 

o the ingestion of vegetables irrigated with 

radionuclide-bearing ground water; and 

o the ingestion of animal products (meat and milk) from 

livestock that ingested contaminated forage. 

Although it is recognized that any of these exposure scenarios could be 

the most critical (i.e., result in the greatest human exposures) depending on 

the actual circumstances surrounding a release, EPA decided to base release 

values for the ingestion of food solely on the scenario involving the 

ingestion of vegetables contaminated by airborne deposition. The irrigation 

pathway was rejected because, based on the defined exposure scenarios, the 

direct consumption of contaminated ground water would result in greater 

exposures than the ingestion of vegetables irrigated with contaminated ground 

water. In other words, release values calculated for the ingestion of ground 

water would always be lower (under the conditions assumed) than release values 

for the ingestion of vegetables contaminated through irrigation. Ingestion of 

contaminated milk and/or meat was rejected because radionuclide concentrations 

found in milk or meat are highly dependent upon element-specific transfer 

factors between forage and animal products. Transfer factors are available 

for only a few elements and, as such, an acceptable model could not be applied 

to most radionuclides. The models used to evaluate each of these pathways and 

the reasons for choosing the vegetable ingestion pathway are described in 

detail in Appendix C of this report. The method for calculating release 

values for the ingestion of vegetables contaminated by airborne deposition is 

summarized below. 

Conceptually, release values for the ingestion of vegetables contaminated 

by airborne deposition are calculated for a scenario defined by the following 

assumptions: (1) radionuclides are released to the air over a 24-hour period 

from a point source at ground level; (2) the radionuclide disperses in air in 

a gaussian plume; (3) a portion of the airborne radionuclides deposits on a 

vegetable crop located 30 meters downwind on the first day of the growing 

season; (4) an individual ingests one day's worth of vegetables from the 

contaminated crop for a period of 60 days, the entire length of the growing 

season; and (5) the vegetables are not washed or stored after harvest, but 
P.38 

4-10 

rather are ingested directly. EPA recognizes that this scenario is very 

conservative, particularly with respect to the assumption of a vegetable crop 

being located just 30 meters downwind from the point of release. These 

conservative assumptions, as well as the equations used to model this pathway, 

tend to exaggerate the importance of the vegetable ingestion pathway relative 

to the other pathways. Basing the release values on these conservative 

assumptions, however, assures that there will be timely reporting for most 

conceivable release situations. 

The vegetable ingestion release values represent the quantity of 

radionuclides that, if released under the set of assumptions outlined above, 

could result in an exposed individual receiving an effective dose-equivalent 

of 500 millirem. The basic equation used to calculate these release values 

is: 

(5) Vegetable Ingestion 

Release Value = ALI/((10)*(DF)*(FC)*(CT)*(R)*(1 x 106)) 

(in curies) 

where: 

ALI = Annual Limit of Intake for ingestion (microcuries); 

10 = Factor to adjust the dose-equivalent limit built into the 

ALI, 5 rem, to a limit of 0.5 rem (dimensionless); 

DF = Dilution factor accounting for the transfer of 

radionuclides from air to vegetation (curies/kg of 

vegetables at the point of exposure per curie released to. 

the atmosphere); 

FC = Food (i.e., leafy vegetable) consumption rate of reference 

man (0.175 kg/day); 

CT = Contact time, or the number of days over which 

contaminated vegetables are ingested; 

R = Airborne release fraction (dimensionless); and 

1 x 10° = Conversion factor between microcuries and curies. 

The ALIs used in Equation (5) were taken from ICRP Publication 30. When 

more than one ingestion ALI was reported for a single radionuclide, the lowest 

one was used. Selecting the lowest ALI assures that the release values are 

based on the most hazardous chemical form of a radionuclide. 

As described in detail in Appendix C, the dilution factor is based on the 

concentration of radionuclides in air over a vegetable crop and the extent to 

which the radionuclides deposit on and in the vegetables. The atmospheric 

relative concentration (X/Q) value used in the inhalation pathway equation was 

used to estimate the concentration in air at a point 30 meters downwind from 

the point of release. A model presented by the NCRP in NCRP Commentary No. 
P.39 

4-11 

3

11 was used to determine the transfer of radionuclides from air to 

vegetation. This model accounts for the radionuclide deposition velocity, 

radionuclide loss due to weathering, uptake from soil, time period that the 

crops are exposed to contamination, and several other factors. 

The value used for the food consumption rate is the rate that leafy 

vegetables are consumed by reference man. The selected value, 0.175 kg/day, 

is used commonly in radiological assessments. The airborne release 

fraction, R, represents the portion of a released radionuclide that actually 

becomes airborne. The values used for R in Equation (5) are the same ones 

that are used in the calculation of inhalation release values (see Section 

4.2), and are based on the values presented in the Nuclear Regulatory 

Commission's NUREG-1140 for severe accident situations. The values used are 

shown in Exhibit A-l in Appendix A. 

Although it was assumed that the exposed individual ingests contaminated 

vegetables for 60 days, this time period was adjusted for radioactive decay 

and weathering loss to derive an equivalent contact time (CT) for use in 

Equation (5). The dilution factor outlined above, when applied to the 

quantity of radionuclide released in one day, yields the concentration of 

radionuclide in and on vegetation after one day. Over the next 60 days that a 

person is assumed to ingest the vegetables, the radionuclide concentration 

will progressively decrease as more and more of the contamination is lost due 

to radioactive decay and weathering. Therefore, the value used for CT in 

Equation (5) is derived using an exponential decay expression that accounts 

for the amount of radionuclide lost over the 60 day ingestion period. A 

different CT value is calculated for each radionuclide as a function of the 

radionuclide's half-life. The expression used to calculate CT is presented in 

Appendix C. 

Finally, no radioactive decay is considered during the period of release 

and deposition. This approach is taken because decay during airborne 

transport to and deposition on vegetation located 30 meters away would be 

negligible for most radionuclides. 

The release values calculated using Equation (5) are presented in 

Appendix E under the heading "Ingestion (Food)." 

•'-"'-National Council on Radiation Protection and Measurements, Screening 

Techniques for Determining Compliance with Environmental Standards: Releases 

of Radionuclides to the Atmosphere. NCRP Commentary No. 3, 1986. 

-1 o 

•""^U.S. Nuclear Regulatory Commission, Calculation of Annual Doses to Man 

from Routine Releases of Reactor Effluents for the Purpose of Evaluating 

Compliance with 10 CFR Part 50. Appendix I. Regulatory Guide 1.109, Revision 

1, October 1977. Table E-5 (page 1.109-40) of this Guide recommends, in lieu 

of site-specific data, use of a leafy vegetable consumption rate of 64 kg/year 

to assess the doses to maximally exposed adults. For the purposes of this 

analysis, 64 kg/year was divided by 365 to obtain 0.175 kg/day. 
P.40 

4-12 

4.5 RELEASE VALUES FOR THE DIRECT EXPOSURE PATHWAY 

The methodology for determining release values for direct exposure to 

radiation depends on the form of the radionuclide released. For certain noble 

gas isotopes, the release values are based on exposure due to total body 

submersion in a radioactive gas cloud. For all other radionuclides, release 

values are based on the quantity of radioactivity received by an individual 

exposed to a point source of radiation. The calculation of release values for 

point source and noble gas releases are summarized below and described in 

greater detail in Appendix D of this report. The release values calculated 

for direct exposures are presented in Appendix E. 

4.5.1 Direct Exposure From a Point Source 

As is the case for the other exposure pathway analyses, the calculation 

of direct exposure release values assumes that a person 30 meters from the 

point of a radionuclide release receives an effective dose-equivalent of 500 

millirem. Assuming that a person is 30 meters from the point of release, 

direct exposure hazards are associated almost entirely with neutrons and gammarays; the range in air of all alpha particles and most beta particles is far 

less than 30 meters.

 3 Therefore, to determine release values for direct 

exposures to a point source, EPA considered both the exposure to neutrons and 

the exposure to gamma rays. 

Of the 757 radionuclides listed in ICRP Publication 30, 24 decay at least 

part of the time by spontaneous fission and emit neutrons. As described in 

Section D.1.2 of Appendix D, the Agency calculated release values for these 

nuclides based on direct exposure to neutrons. The exposure scenario assumed 

in the calculation of these release values is similar to that assumed for the 

other exposure pathways, i.e., a person stands 30 meters from a point source 

for 24 hours and receives a whole body dose-equivalent of 500 millirem. In 

all cases, the direct epxosure release values for the neutron-emitting 

isotopes were less than the corresponding release values calculated for the 

inhalation pathway. The usual mode of decay for the 24 isotopes (certain 

uranium isotopes and isotopes of some transuranic elements) is the emission of 

alpha particles, which can cause significant biological damage when emitted 

inside the body. Under the exposure conditons assumed, therefore, the RQs for 

these isotopes would not be based on the direct exposure to neutrons and this 

exposure pathway was dropped from further consideration. 

J3For example, a 10 MeV alpha or beta particle would be an extremely 

energetic particle. The mean range of a 10 MeV alpha particle in air is less 

than 15 centimeters. Beta particles typically range in energy between 0.04 

and 6 MeV, although there are a few radionuclides which emit beta particles 

with higher energies (e.g., the maximum beta particle energy for carbon-15 and 

bromine-87 is about 10 and 8 MeV, respectively). The mean range of a 6 MeV 

beta particle in air is only about 20 meters and these high energy beta 

particles are very rare. Therefore, although there are a few nuclides for 

which beta particles can conceivably travel approximately 30 meters in air, 

exposures at this distance are for the most part only a concern for gamma rays 

and neutrons. 
P.41 

4-13 

The method used by the Agency for calculating direct exposure release 

values from a fixed point source of gamma rays is adapted from the Health 

Physics and Radiological Health Handbook1^ and includes gamma ray attenuation 

in air between the source and the receptor. It reflects the effects of gamma 

radiation and can be simplified, as shown in Appendix D, to yield the 

following equation: 

(6) Direct Exposure Release Value = 

((6.41xlO-5)*(Dn)*(S2))/((E1)*(ua)*(T)*(exp(-100uaS))) 

where: 

Dn = Dose-equivalent in rem (0.5 rem or 500 millirem); 

S = Distance from the release (30 m) ; 

E^ = The sum of the products of the gamma ray energies and the 

gamma ray fractions (MeV); 

ua = Linear energy absorption coefficient for gamma rays in air 

(cm'1); 

T = Duration of exposure (in hours); and 

exp(-100uaS) = Attenuation factor (dimensionless). 

The direct exposure release value was calculated using Equation (6) for 

every radionuclide of interest that emits a gamma ray. For many of these 

radionuclides, gamma rays are not emitted every time that the nuclide decays 

(i.e., disintegrates). In addition, a gamma ray that is emitted from a given 

radionuclide does not necessarily always have the same energy level. This 

phenomenon is illustrated in Exhibit 4-1. As shown in this exhibit, every 

time argon-41 disintegrates, it emits a gamma ray with an energy level of 1.3 

MeV. Krypton-85 emits a gamma ray for only a small fraction of its 

disintegrations (0.4 percent), while several different gammas with different 

energies are emitted at different frequencies by molybdenum-99. 

To account for these various gamma ray energies and fractions when using 

Equation (6), the energy level (E.. ) for a given radionuclide was derived by 

taking the sum of the products of the gamma ray energies and the gamma ray 

fractions. For example, the E value used for argon-41 was 1.3 MeV and the E1 

value used for molybdenum-99 was 0.14. This approach considers all of the 

gamma rays for a given radionuclide and accounts for the fraction of time that 

such a gamma ray is actually emitted. 

The linear energy absorption coefficient for gamma rays in air (u ) 

varies with the gamma ray energy. When the gamma ray energy is 1 MeV, the 

^Nucleon Lectern Associates, The Health Physics and Radiological Health 

Handbook. 1984, p.41. 
P.42 

4-14 

EXHIBIT 4-1 

GAMMA RAY ENERGIES, GAMMA RAY 

FRACTIONS, AND ENERGY LEVELS FOR SELECTED RADIONUCLIDES 

Radionuclide 

Gamma Ray 

Energy, E 

(MeV) 

Gamma Ray 

Fraction 

(percent) 

Gamma Ray 

Fraction 

Times E 

(MeV) 

Radionuclide 

Energy Level, 

El 

(MeV) 

Argon-41 

Krypton-85 

Molybdenum-99 

1.3 

0.513 

0.041 

0.141 

0.181 

0.366 

0.740 

0.777 

0.822 

100 

0.43 

1 

5 

6 

1 

12 

4 

0.1 

1.3 

2.2x10 

4.1x10 

70.5x10' 

108.6x10" 

36.6x10" 

88.8x10 

310.8x10 

8.2x10 

-4 

-4 

1.3 

2.2x10 

0.14 

Source: National Council on Radiation Protection and Measurements, A 

Handbook of Radioactivity Measurement Procedures. NCRP Report 

No. 58. Washington, D.C. November 1978. 
P.43 

4-15 

linear energy absorption coefficient is 3.7 x 10 /cm.^ For gamma rays with 

energies between 0.07 MeV and 2 MeV, the absorption coefficient will vary from 

3.7 x 10 by plus or minus 15 percent. Because the variation is so slight, 

for purposes of calculating the direct exposure release values, EPA assumed 

that the absorption coefficient is 3.7 x 10 /cm for all radionuclides of 

concern. 

The duration of exposure, T, is assumed to be 24 hours. Because of 

radioactive decay, however, it is recognized that a person would be exposed to 

successively smaller quantities of radioactivity over this period of exposure. 

To determine an individual's cumulative exposure over the 24-hour period, 

therefore, a different exposure duration is calculated for each radionuclide 

using an integrated decay expression that accounts for the extent of 

radioactive decay that would occur over 24 hours. This expression is as 

follows: 

(7) T = 1- exp(-Xt) 

X 

where: 

X= 0.693/t-]/2, where t]/ 2 is the radionuclide half-lif e in days.; 

and 

t = 1 day. 

Multiplying the T derived from Equation (7) by 24 (i.e., 24 hours/day) yields 

a duration of exposure in units of hours, which can be plugged into 

Equation (6). 

While dec ay over the period of exposure is taken into account through 

Equation (7), the Agency decided to ignore the effects of radioactive decay 

over the period of release and the period of transport to a receptor. The 

release is assumed conservatively to be instantaneous, such that no decay over 

the release period would occur. It is impossible to put bounds on the length 

of time necessary for a person to come into contact with direct radiation from 

a released point source. The Agency conservatively assumed, therefore, that 

no decay occurs over this "transport time." 

Substituting all of the values outlined above into Equation (6), the 

equation "simplifies to: 

(8) Direct Exposure = 25.1 

Release Value (E1)*(t1/2 " tl/2 exp(-0.693/tw2)) 

Direct exposure release values calculated for the radionuclides that emit 

gamma rays are presented in Appendix E of this report. 

J-->Nucleon Lectern Associates, The Health Physics and Radiological Health 

Handbook. 1984, p.41. 
P.44 

4-16 

4.5.2 Submersion in a Radioactive Cloud of Noble Gas 

Because the noble gases argon, krypton, and xenon are chemically very 

stable, they are not likely to form solid or liquid compounds that can be 

ingested. Also, because they are relatively insoluble in blood and are 

displaced easily by gases more common in air such as oxygen and nitrogen, 

these noble gases are not incorporated readily into the body after inhalation. 

As a result, ingestion and inhalation are not significant exposure pathways 

and ALIs for ingestion and inhalation were not developed by the ICRP for most 

noble gases. However, submersion in a radioactive cloud can cause a 

significant whole body dose due to direct exposure. Therefore, direct 

exposure release values for argon, krypton, and xenon were derived assuming 

that an exposed individual is submerged in a cloud of the gas 30 meters from 

the release point. 

Argon, krypton, and xenon are the only noble gases whose release values 

are calculated based on total submersion in a cloud. The noble gases helium 

and neon do not form isotopes with half lives longer than a few seconds. ALIs 

for these isotopes have not been developed and, therefore, no release values 

have been calculated. The noble gas radon has two isotopes (radon-220 and 

radon-222) with inhalation ALIs. Inhalation of radon, rather than submersion 

in a cloud, was considered because the critical health effect associated with 

exposure to radon is caused by inhalation of its short-lived decay products. 

EPA recognizes that a cloud of non-noble gases can also contribute to a dose 

through the submersion-in-a-cloud pathway, in the same manner as noble gases. 

However, it is generally recognized that, in this situation, the inhalation 

pathway is controlling. Therefore, direct exposure by submersion in a cloud 

was analyzed for only argon, krypton, and xenon. 

A different equation for the calculation of direct exposure release 

values is appropriate for radioactive noble gases because submersion in a 

cloud results in an integrated dose from all directions at varying distances 

from the body. The direct exposure release values for submersion in a 

radioactive cloud of a noble gas are derived through the following equation." 

(9) Direct Exposure , 

Release Value = ((83)*(DAC)*(T))/((10)*(X/Q)*(lxl0 )) 

where: 

o 

DAC = Derived Airborne Concentration (microcuries/cmJ); 

T -= Duration of Exposure (1 day); 

This equation is derived from an equation found in the Annals of the 

ICRP. Publication No. 30, Part 1, Volume 2, No. 3/4, 1979, pp. 10 and 47. See 

Appendix D for more detials. 
4-17 

X/Q -= Atmospheric Relative Concentration Value at 30 meters 

(8.4x10 day/cm3); and 

1x10 = Conversion factor between microcuries and curies. 

The DAC value specifies the airborne concentration that would result in a 5 

rem whole body dose-equivalent for a 2000 hour exposure period. To adjust the 

airborne concentration from a 2000 hour to a 24 hour exposure period, the DAC 

value in Equation (9) is multipled by 83 (i.e., 2000 hours/24 hours).17 The 

factor of 10 in the denominator of Equation (9) converts the 5 rem whole body 

limit for occupational exposure to the 0.5 rem (500 millirem) limit for 

exposure to the general public. X/Q is the ground-level concentration value 

30 meters from the release point (see Section 4.2 above and Appendix A for 

further discussion of X/Q). 

The effects of radioactive deay are ignored in Equation (9). This 

pathway model considers exposure to an airborne plume of radionuclides just 30 

meters from the point of release. The time of transport to the exposure point 

is short (30 seconds assuming a 1 meter/second wind), and decay over this 

period would be negligible for most radionuclides. Although the period of 

exposure is assumed to be one day, an individual would not be exposed to the 

same radionuclides over this period. As the plume passes the point of 

exposure, "new" radionuclides just released would approach the individual 

while "old" ones would move farther downwind. Again, because the time of 

travel to a point 30 meters from the point of release is short, the "new" 

radionuclides that the person is repeatedly exposed to would not have decayed 

significantly. For this reason, decay over the period of exposure was 

ignored. 

The expression for determining the release value for the direct exposure 

pathway due to submersion in a cloud of radioactive noble gas can be 

simplified by multiplying the numbers in the numerator and denominator. 

Equation (9) simplifies to: 

(10) Direct Exposure Release Value = DAC/(lxl0" ) 

The direct exposure release values for argon, krypton, and xenon can be found 

at the end of this report in Appendix E. 

1'If a different exposure period was assumed, the DAC value in Equation 

(9) would have to be multiplied by a number different than 83. For example, 

if an exposure period of 12 hours was assumed, the DAC would have to be 

multiplied by 166 (2000/12). . This change would have to be accompanied with a 

corresponding change in T; the value for T would be 0.5 day rather than 1 day. 

For this reason, the direct exposure release value would not increase with 

longer exposure periods as is implied by Equation (9) (one would expect 

intuitively that the release value and exposure duration would be inversely 

related). 
4.6 

4-18 

ASSIGNMENT OF RADIONUCLIDES TO RQ GROUPS 

P.46 

Appendix E at the end of this report displays the four release values 

calculated for each radionuclide. The lowest release value for each 

radionuclide has an asterisk beside it. The lowest release values range from 

over 100,000 curies to approximately 0.001 curie. For administrative 

feasibility and simplicity, the Agency decided to assign the radionuclides to 

one of seven distinct groups identified by specific final RQs. Each 

radionuclide is assigned a final RQ of 0.001 curie, 0.01 curie, 0.1 curie, 1 

curie, 10 curies, 100 curies, or 1000 curies. Assignment of an adjusted RQ to 

a particular radionuclide was made by examining the lowest release value for 

each radionuclide and rounding that value down to the nearest RQ group. 

The 757 radionuclides with RQs are represented as follows: 

o 7 radionuclides (1%) have lowest release values less 

than 0.01 curie and, therefore, have an adjusted RQ 

of 0.001 curie; 

o 29 radionuclides (4%) have lowest release values 

greater than or equal to 0.01 curie but less than 0.1 

curie and, therefore, have an adjusted RQ of 0.01 

curie; 

o 29 radionuclides (4%) have lowest release values 

greater than or equal to 0.1 curie but less than 1 

curie and, therefore, have an RQ of 0.1 curie; 

o 32 radionuclides (4%) have lowest release values 

greater than or equal to 1 curie but less than 10 

curies and, therefore, have an RQ of 1 curie; 

o 220 radionuclides (29%) have lowest release values 

greater than or equal to 10 curies but less than 100 

curies and, therefore have an RQ of 10 curies; 

o 235 radionuclides (31%) have lowest release values 

greater than or equal to 100 curies but less than 

1000 curies and, therefore, have an adjusted RQ of 

100 curies; and 

o 205 radionuclides (27%) have lowest release values 

greater than or equal to 1000 curies and, therefore, 

have an RQ of 1000 curies. 

An RQ of 1 curie also is assigned to all radionuclides not listed in 

ICRP's Publication 30. The Agency believes, for three reasons, that by 

establishing an RQ for the broad generic class "radionuclides," it is 

fulfilling the CERCLA mandate to protect public health, welfare, and the 

environment. First, as seen above, the 1-curie RQ is the middle RQ level and 

the majority (91%) of the radionuclides with proposed RQs have minimum release 

values greater than or equal to 1 curie. Therefore, the generic RQ of 1 curie 

for all other radionuclides (i.e., those not included in the list of 757 
P.47 

4-19 

radionuclides with specific RQs) is probably a conservative value. Second, 

most of the radionuclides that fall into this category are rare, both in terms 

of frequency of use and quantities used. Many of these nuclides have been 

produced in only a few isolated research projects and the world's total 

quantity of many is less than 1 curie. Therefore, releases of radionuclides 

not listed by ICRP Publication 30 are expected to be infrequent and, if they 

occur, are expected to be released within any 24-hour period in quantities 

smaller than 1 curie. Finally, many of the remaining radionuclides have short 

half-lives and do not decay into other radioactive isotopes. Under most 

realistic release situations, these radionuclides would be expected to decay 

and virtually disappear before they could reach receptor locations. 

Two or more radionuclides with the same RQ do not reflect a determination 

that a release of one will be as hazardous as the release of another, or even 

that the release of one will be hazardous at the proposed RQ level and not 

hazardous below that level. The Agency has found that the actual hazard will 

vary with the unique circumstances of the release, and extensive scientific 

data and analysis would be necessary to determine the hazard presented by each 

substance under a number of possible circumstances. Instead, the RQs aredesigned to be a trigger for notification and reflect the Agency's judgment 

that the federal government should be notified of certain releases to which a 

federal response might be necessary. The reportable quantities represent a 

determination only of possible or potential harm, not that releases of a 

particular amount of a hazardous substance necessarily will be harmful to 

public health or welfare or the environment. 

4.7 REPORTING REQUIREMENTS FOR MIXTURES OF RADIONUCLIDES 

Some releases of radioactive substances are likely to consist of mixtures 

of radionuclides. These releases will be one of two general types: mixtures 

of known composition or mixtures of unknown composition. The conventions 

adopted by the Agency in establishing reporting requirements for mixtures and 

the RQs for four common radionuclide mixtures are presented below. 

4.7.1 Mixtures of Known Composition 

Reporting requirements for releases involving mixtures of known 

composition can be obtained directly from the RQs for individual constituents 

of the mixture. If the identity and quantity of each radionuclide involved in 

a release" event is known, the decision to report a release must be made in the 

following manner: for each radionuclide in the mixture, the ratio between the 

quantity released (in curies) and the RQ for the radionuclide must be 

determined. If the sum of the ratios for all radionuclides is less than 1, 

the release need not be reported. If the sum is equal to or greater than 1, 

the release must be reported to the National Response Center. 

For example, if radionuclides "a," "b," and "c" are released in 

quantities of Qa, Qb, and Qc curies in a mixture, and if the RQs are RQa, RQb, 

and RQc, respectively, then the quantity released for the mixture does not 

exceed the RQ and the release need not be reported to the National Response 

Center if (Qa/RQa + Qb/RQb + Qc/RQc) is less than 1. This convention for 

handling releases of radionuclide mixtures is recommended by the ICRP. 
P.48 

4-20 

4.7.2 Mixtures of unknown Composition 

Reporting requirements for mixtures of unknown composition cannot be 

based on the determination of quantities released. For mixtures of unknown 

composition, there are three possibilities: (1) the identity of the 

radionuclides involved is known, but the amounts released of each are unknown, 

(2) the identity of the radionuclides (or one of the radionuclides) in the 

mixture is unknown, but the amount released is known in total curies per unit 

volume or weight, or (3) the identity of the radionuclides involved is unknown 

and the amount of individual radionuclides released in the mixture is unknown 

(but the total quantity is known). For these cases, the decision to report a 

release is made as follows: 

(1) Identity known, but amount unknown. 

If the identity of each radionuclide in the 

mixture is known but the concentration of one or 

more of the radionuclides is unknown, the RQ for 

the mixture shall be the lowest RQ of any 

radionuclide in the mixture. 

This method for determining the RQ of a mixture assures a report to the 

National Response Center if the total number of curies involved in a release 

is equal to or greater than the RQ in curies of the substance with the lowest 

RQ in the mixture. 

(2) and (3) Identity of radionuclide(s) in the release is 

unknown. 

If the identity of a radionuclide in a release 

is unknown or if the identity of one or more 

radionuclides in the release of a mixture of 

radionuclides is unknown, the release must be 

reported to the National Response Center if the 

total release is equal to or greater than 1 

curie, or if the total release is equal to or 

greater than the lowest RQ of any known 

radionuclide in the mixture, which ever is 

lower. 

Establishing an RQ of 1 curie for a release in which the identity of the 

radionuclide or radionuclides involved is unkown is consistent with the 1-

curie RQ for the class of radionuclides for which insufficient data exist to 

extablish individual RQs. The mixture rule requires reporting if the release 

equals or exceeds 1 curie, or, if some component of the mixture is known and 

its RQ is less than 1 curie, then the total release must be reported if it 

equals or exceeds the RQ of the known component. 

4.7.3 Common Radionuclide Mixtures 

RQs have been developed for four common radionuclide mixtures: 

radium-226 in equilibrium with its daughters, natural uranium not in secular 

equilibrium with its daughters, natural uranium in secular equilibrium with 
P.49 

4-21 

its daughters, and natural thorium in secular equilibrium with its daughters. 

Mixed fission products are also recognized by the Agency as an important and 

common radionuclide mixture. However, the Agency is presenting RQs currently 

only for the individual radionuclide components within this latter mixture 

because an RQ for mixed fission products would be time dependent. That is, at 

different time intervals, the concentration of the different components of 

this mixture will be different. In addition, the components of the mixed 

fission product will differ, depending on the type of reactor involved in 

their production. Therefore, several different mixed fission product RQs 

would need to be presented. 

Radium-226 has a half life of about 1600 years, substantially greater 

than the half lives of its eleven daughters. After a sufficient period of 

time, however, a state of equilibrium is established in the mixture (known as 

secular equilibrium), such that the activity present for each daughter product 

and the parent radium is equal. For example, if one curie of radium-226 is 

released, when equilibrium is reached, the activity level of the mixture will 

be 12 curies. When radium and its daughters reach this state of equilibrium, 

its RQ is 0.053 curie.18 

Natural uranium is composed of the isotopes U-238 (99.27 percent by 

weight), U-234 (0.0057 percent by weight), and U-235 (0.72 percent by weight). 

Because the composition by weight of natural uranium is known, we can derive 

the activity levels of each of its components. The rule results in an RQ for 

natural uranium, derived through the mixture rule, of 0.1 curie, if the 

natural uranium is not in equilibrium with its daughters. If the natural 

uranium is in secular equilibrium with its daughters, the RQ derived through 

the mixture rule is 0.052 curie. 

Natural thorium consists of 100 percent Th-232. When in secular 

equilibrium with its daughters, the RQ for natural thorium is calculated using 

the mixture rule to be 0.011 curie. 

4.8 REPORTING REQUIREMENTS FOR COMPOUNDS AND MIXTURES OF RADIONUCLIDES AND 

OTHER HAZARDOUS SUBSTANCES 

The final RQs are for radionuclides, which are species of atoms defined 

by their atomic number and mass. These RQs are applicable to all chemical and 

physical forms in which the radionuclides may exist. EPA recognizes that 

because the radionuclide RQs are applicable to all chemical forms, some 

-1 Q 

-"-"Kaplan, I., Nuclear Physics. Addison-Wesley Publishing Company, 

Reading, Massachusetts, 1958, p. 202. Using the mixture rule, the RQ for 

radium in equilibrium with its daughters was calculated from the following 

formula: 

1 1 12 1 

= _ L 

RQmix

 1 2 i= 1 RQi 

where: 

RQi is the reportable quantity of radium or the daughter of concern. 
P.50 

4-22 

substances containing radionuclides will have two applicable RQs, one based on 

radiation hazard and the other based on chemical toxicity. In such 

situations, the lowest applicable RQ for a substance governs when the owner or 

operator must report the release to the National Response Center. In this 

way, the RQs reflect the relative chemical toxicity and radiation hazard of a 

substance. 

For example, naturally occurring cadmium consists of roughly 12 percent 

cadmium-113, a radioactive isotope, and several other isotopes of cadmium that 

are not radioactive. The RQ for cadmium has been finalized at 10 pounds and 

the RQ for cadmium-113, just one component of naturally occurring cadmium, is 

0.1 Ci. A releaser of cadmium metal is required to report if either 10 pounds 

of the metal (if the diameters of the particles of the released metal are less 

than or equal to 100 micrometers) or 0.1 Ci of cadmium-113 (regardless of the 

particle size of the cadmium-113) is released. In this case, the RQ based on 

chemical toxicity is much more limiting than the RQ based on radiotoxicity (a 

release of 10 pounds of cadmium metal or 10 pounds of cadmium-113 constitutes 

far less than 0.1 Ci). For other materials, however, the RQ based on 

radiotoxicity is more limiting than the one based on chemical toxicity. In 

both situations, the lowest RQ applicable to the substance released would be 

the reporting trigger. 

Uranyl acetate and uranyl nitrate are additional examples of substances 

with two applicable RQs, one based on chemical toxicity and the other based on 

radiation hazard. Both substances are specifically listed as CERCLA hazardous 

substances because they are included under section 311 of the CWA; however, 

they both consist of about 60 percent uranium-238, a radionuclide. Based on 

their chemical toxicity, uranyl acetate and uranyl nitrate have a final 

adjusted RQ of 100 pounds (51 FR 34534, September 29, 1986). The final RQ for 

uranium-238, based upon radiological hazard, is 0.1 Ci, which is equivalent to 

roughly 660 pounds of uranium-238. Both the 0.1 Ci RQ for uranium-238 and the 

100 pound RQ are applicable to releases of uranyl acetate and uranyl nitrate, 

but the 100-pound RQ will always trigger reporting first because it is the 

lower, more protective level. The RQ of 100 pounds will assure timely 

reporting of releases of uranyl acetate and uranyl nitrate from both a 

radiological hazard and chemical toxicity standpoint. 
P.51 

APPENDICES 

I 
P.52 

APPENDIX A 

MODELING THE AIRBORNE RELEASE AND INHALATION 

OF RADIONUCLIDES 

This appendix documents the model used to calculate 

inhalation release values (RVs) which are a component in the 

adjustment of radionuclide RQs. The inhalation release values 

represent the quantity of a-radionuclide (in units of curies) 

that, if released into air under an assumed set of conditions, 

could result in an exposed individual receiving an effective 

dose-equivalent of 500 millirem through the inhalation pathway. 

The inhalation RVs calculated for each radionuclide can be found 

in Appendix E of this report. 

This appendix is divided into three main sections. The 

first section presents the basic model used to calculate 

inhalation RVs, defines the input parameters, and discusses the 

basic rationale underlying the model. In sections A.2 and A.3, 

the basis for two key input variables used in the model, the 

airborne release fraction and the atmospheric relative 

concentration value, respectively, is presented. 

A.l THE INHALATION MODEL 

Radionuclides can be released into the air in several 

different ways and at any rate. In order to calculate meaningful 

release values for the adjustment of RQs, it is necessary to use 

a model that is realistic (i.e., reflects release and exposure 

conditions that may actually occur) but conservative enough to 

yield timely reporting for most release situations. The model 

selected for this purpose assumes that: (1) radionuclides are 

released to air from a point source at ground level; (2) the 

radionuclides disperse in the atmosphere in a gaussian plume; and 

A-l 
(3) an individual is exposed at a position 30 meters downwind 

from the point of release and remains in the plume centerline, 

the point of maximum concentration, for the entire release 

period. Under this set of conditions, the size of the release in 

curies (the release value) necessary to provide a 500 millirem 

effective dose-equivalent to the exposed individual can be 

calculated using equation (1): 

Inhalation 

Release Value = ALI/[(10)*(R)*(X/Q)*(BR)*(1 x IO6)]. (l) 

(Ci) 

where: 

ALI = annual limit of intake for inhalation (microcuries); 

10 factor to convert the annual limit of intake which is 

based on 5 rem dose-equivalent to a worker in a 

nuclear facility to 0.5 rem, the Federal Radiation 

Protection Guideline for exposure to members of the 

general public; 

R = airborne release fraction; 

X/Q = atmospheric relative concentration value at a position 

30 meters downwind (8.4 x 10~13 day/cubic cm); 

BR = breathing rate for reference man (2.3 x IO7 cubic 

cm/day); and 

1 x 10s conversion factor between microcuries and curies. 

The inhalation ALIs used in the calculations are taken from 

ICRP's Publication 301 after being converted from becquerels to 

microcuries. Where more than one ALI was given for a particular 

radionuclide, the lowest value was used for the calculations. 

This assures that the most hazardous chemical form of a 

radionuclide is used in the release value calculations. 

international Commission on Radiological Protection (ICRP), 

"Limits for Intakes of Radionuclides by Workers," Publication 30, 

Part 2, 1980. 

A-2 

I 

I 
P.54 

There are two important points to clarify with respect to 

equation (1). First, the model ignores the effects of 

radioactive decay. This is because the pathway model considers 

exposures to an airborne plume of radionuclide. A short-lived 

radionuclide could undergo significant decay if the release and 

exposure periods were as long as one day, but decay would be much 

less if a time period of a few hours, minutes or seconds was 

considered. Because it was not possible to establish exact 

bounds on the range of release and exposure periods (note that 

the equation does not include a specific time factor for these 

periods), the Agency conservatively assumed that no decay occurs 

over these periods. EPA also ignored decay over the period of 

radionuclide transport to the point of inhalation. This approach 

was adopted because decay during airborne transport to a receptor 

3 0 meters downwind would be negligible for most of the 

radionuclides considered. 

Second, it is recognized that the point source ground level 

release assumed in the model is not applicable to all release 

configurations. Radionuclides are also commonly emitted to the 

air from areal sources and from raised point sources such as 

smokestacks. Examples of areal sources include coal ash piles 

found at coal-fired boiler sites and open pit mining operations, 

both of which emit radon to the atmosphere. A point source 

release at ground level was assumed in the model because it most 

closely resembles an episodic release for which a response might 

be taken and because it yields more conservative (i.e., lower) 

release values than other release configurations. In this sense, 

the release values calculated under these conditions will assure 

timely reporting for most release situations. Conversely, 

release values that would have been calculated if an areal or 

elevated source had been assumed would not necessarily assure 

timely reporting for releases from a point source at ground 

level. 

A-3 
A. 2 EVALUATION OF THE RELEASE FRACTION 

The release fraction, R, reflects the fraction of a 

radionuclide release that could become airborne and be of 

respirable size (10 microns in diameter or less). The Nuclear 

Regulatory Commission has developed release fractions for 

radionuclides under accident conditions2. These release 

fractions and the "rationale beh-irf-them-are-summarifzectbeiowi - -

Isotopes of the noble gases argon, krypton, radon and xenon 

have been assigned release fractions of 1.0 because they are 

always gases at room temperature, remain mixed with air, and do 

not react chemically to form less volatile compounds. The 

Nuclear Regulatory Commission has assigned a release fraction of 

0.5 to compounds of hydrogen, carbon, phosphorous, sulfur, and 

iodine. Compounds of these elements would be expected to produce 

less than 100 percent volatilized and respirable particles or 

gases for the following reasons: (1) some compounds of the 

elements will settle out on surfaces and not be released to the 

atmosphere, and (2) some particles in the release may not be 

respirable. 

Compounds of the elements selenium, mercury, cesium, 

polonium, tellurium, and ruthenium, among others are only semivolatile and have been assigned release fractions of 0.01. 

Release fractions for non-volatile metals such as uranium, 

Plutonium, tantalum, thorium, and americium, among others, have 

been set at 0.001. For these metals or compounds of these 

metals, the release pathway is not volatilization but entrainment 

of particles in an air stream. Even finely ground powders will 

I 

1 

2McGuire, S.A., "A Regulatory Analysis on Emergency Preparedness 

for Fuel Cycle and Other Radioactive Material Licensees," NUREG1140, June 1985. 

A-4 
P.56 

generally contain less than a few percent of the powder in 

respirable size. The fraction of particles of respirable size is 

kept small by the difficulty in producing small particles and 

subsequently by agglomeration and weathering, processes which 

cause micron-sized particles to stick to surfaces, to larger 

particles and to themselves. 

Release fractions for the various elements may be found in 

Exhibit A-l. Inhalation release fractions were taken from the 

Nuclear Regulatory Commission's NUREG-1140. Where release 

fractions for specific isotopes are shown in NUREG-1140, these 

were used for all isotopes of the element. Where NUREG-1140 does 

not show a release fraction for a specific element or isotope, 

the release fractions were derived by reference to statements at 

the end of the table recommending a release fraction of 0.01 for 

"any other beta-gamma emitter" and a release fraction of 0.001 

for "any other alpha emitter." 

A-5 
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EXHIBIT A-l (Cont.) 

P.59 

Element 

Plutonium 

Polonium 

Potassium 

Praseodymium 

Promethium 

Protactinium 

Radium 

Radon 

Rhenium 

Rhodium 

Rubidium 

Ruthenium 

Samarium 

Scandium 

Selenium 

Silicon 

Silver 

Sodium 

Strontium 

Sulfur 

Tantalum 

Technetium 

Tellurium 

Terbium 

Thallium 

Thorium 

Thulium 

Tin 

Titanium 

Symbol 

Pu 

Po 

K 

Pr 

Pm 

Pa 

Ra 

Rn 

Re 

Rh 

Rb 

Ru 

Sm 

Sc 

Se 

Si 

Ag 

Na 

Sr 

S 

Ta 

Tc 

Te 

Tb 

Tl 

Th 

Tm 

Sn 

Ti 

Release 

Fraction (R) 

0.001 

0.01 

0.01 

0.01* 

0.01 

0.001 

0.001 

1.0 

0.01* 

0.01* 

0.01 

0.01 

0.01 

0.01 

0.01 

0.01* 

0.01 

0.01 

0.01 

0.5 

0.001 -

0.01 

0.01 

0.01 

0.01 

0.001 

0.01 

0.01 

0.01 

A-8 
EXHIBIT A-l (Cont.) 

P.60 

Element 

Tungsten 

Uranium 

Vanadium 

Xenon 

Ytterbium 

Yttrium 

Zinc 

Zirconium 

Symbol 

W 

U 

V 

— Xe -

Yb 

Y 

Zn 

Zr 

Release 

Fraction (R) 

0.01 

0.001 

0.01 

"-*- - 1.0 _ 

0.01 

0.01 

0.01 

0.01 

* Indicates that the release fraction is based on the 

NUREG-1140 release fraction for "any other beta-gamma 

emitter." 

** Indicates that the release fraction is based on the 

NUREG-1140 release fraction for "any other alpha emitter." 

Source: McGuire, S.A., "A Regulatory Analysis on Emergency 

Preparedness for Fuel Cycle and Other Radioactive 

Material Licensees," NUREG-1140. 

I 

I 

A-9 
P.61 

A. 3 DERIVATION OF THE ATMOSPHERIC RELATIVE CONCENTRATION VALUE 

In calculating inhalation release values, it is necessary 

to use atmospheric dispersion modeling to estimate the fraction 

of a release which might be encountered by an individual. The 

atmospheric dispersion parameter needed in equation (1) is the 

atmospheric relative concentration value, Chi over Q (X/Q). The 

value used for X/Q was taken from Exhibit A-2, which is an 

extrapolation of the graph in Exhibit A-3.3 Exhibit A-3 plots 

Xu/Q per square meter versus distance from the source in 

kilometers for releases varying in height from ground level (the 

uppermost line in the plot) to a height of 300 meters. The 

symbol u in Xu/Q stands for wind speed in meters per second. 

Xu/Q is plotted so that a value for X/Q can be derived for any -

wind speed simply by dividing the value found in the plot by the 

desired wind speed. In this analysis, a wind speed of 1 meter 

per second is used, yielding a X/Q in units of seconds per cubic 

meter. 

For the purpose of calculating RQs, some conservative 

assumptions in deriving X/Q have been made. These assumptions 

include: 

1. The distance from the point source release to the point 

of exposure is assumed to be 30 meters (about 100 

feet). In addition, it is assumed that a gaussian 

distribution of the released contaminant is established 

almost immediately within the plume and is fully 

developed at 30 meters. 

3Turner, D. Bruce, "Workbook of Atmospheric Dispersion 

Estimates," EPA Office of Air Programs, 1970. 

A-10 
•9.1 

— 0.01 

—•0.001 

1.0 0.01 

0.0001 

Distance Fran Source (fan.) 

EXHIBIT A-2. X/Q Vs. Distance for a Ground Level Release, 

Stability Class D. 

1 

I 

A-ll 
Xu/Q a 

EXHIBIT A-3. Xu/Q Vs. Distance at Various Heights (H) of Release 

(meters), Stability Class D. 

A-12 

1 

I 
2. The release occurs at ground level. This approach 

gives the highest ground level concentrations and the 

lowest inhalation RVs. 

3. The point of exposure is directly downwind from the 

release in neutral (Class D) atmospheric conditions and 

the wind speed (u) is 1 meter per second. 

4. The material released is a stable gas or aerosol (less 

than 20 microns in diameter) which remains suspended in 

air for long periods_of time. 

5. The gas or aerosol is continuously emitted from the 

source or the emission time is equal to or greater than 

the travel time to the point of exposure. In this 

case, it is possible to omit from consideration 

diffusion in the direction of transport. The equations 

used to produce the graphs in Exhibits A-2 and A-3 are 

valid only if diffusion in this direction is assumed to 

be zero. This is a reasonable assumption because the 

rate of diffusion in this direction would be much 

smaller than the wind speed of 1 meter per second. 

6. None of the material emitted is removed from the plume 

as it moves downwind and there is complete reflection 

from the ground. 

With these assumptions and referring to Exhibit A-2, it is 

possible to obtain a X/Q of 7.2 x 10"2 seconds per cubic meter. 

Because a breathing rate in units of cubic centimeters per day is 

being used in equation (1), it is necessary to convert X/Q to 

compatible units. This leads to a value of 8,4j^ P day per 

cubic centimeter, the value used in this report. 

Most published sources describing gaussian advectiondispersion equations provide graphical representations for X/Q at 

distances from the source as close as 100 meters. The Agency 

recognizes that extrapolation of these values to shorter 

distances may introduce an error in subsequent calculations. The 

extrapolation, however, allows the calculation of conservative 

release values and, for this application, the error which may be 

introduced is believed to be inconsequential. Moreover, it is 

A-13 
P.65 

i 

recognized that several other assumptions in the atmospheric 

dispersion model also yield a conservative X/Q value. 

Alternative assumptions would, of course, yield different values 

for X/Q as discussed below. 

If, instead of extrapolating down to 30 meters, the value 

for a distance of one hundred meters (assuming a ground level 

release) is chosen, X/Q becomes 9.5 x IO"14 day per cubic 

centimeter. This value is almost an order of magnitude smaller 

than the 30 meter value and would lead to inhalation RVs nearly a 

factor of ten higher. Exhibit A-3 also shows values for plume 

heights (H) greater than ground level (H = 10 to H = 300 meters). 

Plume heights are not necessarily the same as the stack height 

and are affected by phenomena such as inversion layers, wind 

speeds, and the velocity of stack ejecta. In any case, it is 

clear from Exhibit A-3 that if RVs were to be calculated on the 

basis of a release from above ground level, they would be much 

larger. For example, in the case of a release 20 meters above 

ground, the calculated X/Q is approximately 1 x 10~17 day per 

cubic centimeter at one hundred meters, a factor nearly ten 

thousand times smaller than that for a ground level release. If 

calculated at 350 meters (the point of maximum concentration 

according to Exhibit A-3) the value would be 3.5 x IO"15 day per 

cubic centimeter, a value more than 200 times smaller than the 

value used in equation (1). 

The graphs shown in Exhibits A-2 and A-3 and used for the 

determination of X/Q are generated from the equations for 

atmospheric modeling and are intended to simplify the task of 

determining X/Q. The generally accepted expression for the 

concentration, X (chi), of gas or aerosols at point x,y,z from a 

continuous source with an effective emission height, H, is given 

in the equation below. The coordinate system referred to can be 

found in Exhibit A-4. 

A-14 
P.66 

X(x,y.z;H) . exp 

2T a y ffxu t-&)]H-e)]-K^)]} <« 

where: 

X » chi, concentration (Curies/m3); 

x,y,z = positions in the coordinate systems (see Exhibit 

Q = release rate (curies/sec) ; 

7r = pi (3.14159, approximately); 

ay = horizontal dispersivity (meters); 

o z = vertical dispersivity (meters) ; 

u = wind speed (meters per second); 

exp = exp (-a/b) = e(~a/

b) where e is the base of 

natural logarithms and is approximately equal to 

2.7183; and 

H = the effective emission height (meters). 

Several assumptions are made concerning the hypothetical 

release which result in the simplification of Equation (2). 

These simplifications are shown below. 

For concentrations calculated at ground level for a ground 

level release (i.e., z = 0) the equation simplifies to: 

Xfx.y.O.H, -^^ exp J- *(£-)2]«P ["T^) 2 ] O) 

A-15 
3=> 

l — » 

t(*.-y.z ) 

*.y.O) 

EXHIBIT A-4. Coordinate System for Atmospheric Modeling Showing Gaussian 

Distributions in the Horizontal and Vertical. 
Where the concentration is to be calculated along the 

centerline of the plume giving the maximum concentration (i.e., 

y = 0): 

X(x,0,0;H) = ^ exp 

y z [XI (4) 

For a ground level source with no effective plume rise 

(i.e., H = 0), the equation simplifies even further: 

X(x,0,0;0) = ^ (5) 

y z 

The values for dispersion in the y and z directions (ay and 

az) vary with the turbulent structure of the atmosphere, height 

above the surface, surface roughness, sampling time over which 

the concentration is to be estimated, wind speed, and distance 

from the source. Values for (7y and az are estimated for each 

atmospheric stability class, which include an estimated wind 

speed. Stability class D, used here, assumes a light wind in 

overcast conditions during either day or night. Using Stability 

Class D results in higher concentrations and lower RQs than would 

more turbulent stability classifications. The estimates for 

horizontal and vertical dispersion coefficients can be found in 

the Workbook of Atmospheric Dispersion Estimates.4 Rearranging 

Equation (5), above, as shown, and applying values for cry and 

a z from the graph in Exhibit A-5 yields: 

1 l -2- 2 

Xu/Q = = = 7.5 x 10

 L

 m

 c

. (6) 

* O a 7T(2.6)(1.65) 

4Turner, D. Bruce, "Workbook of Atmospheric Dispersion 

Estimates," EPA Office of Air Programs, 1970. 

A-17 
P.69 

100 

1000 100 

Distance Downwind, meters 

EXHIBIT A-5. Horizontal and Vertical Dispersion Coefficient as a 

Function of Downwind Distance From the Source. 

A-18 
P.70 

Division of both sides of the equation by a wind speed, u, 

of 1 meter per second gives: 

X/Q = 7.5 x 10~2 sec m"3. (7) 

Considering the possibilities for error introduced in 

extrapolation, this value agrees very well with the value found 

by reference to Exhibit A-2 (7.2 x 10~2 sec m~ 3 ) . 

A-19 
P.71 

APPENDIX B 

MODELING THE INGESTION OF CONTAMINATED 

DRINKING WATER 

Drinking water in the United States is usually obtained from 

one of two sources: wells drilled into subsurface aquifers or 

surface sources such as reservoirs, lakes or rivers. Any of 

these drinking water sources can become contaminated from a 

release of radionuclides. The Agency has calculated ingestion 

release values for both subsurface aquifers and for rivers in 

order to determine which might provide the more critical pathway 

for consumption of contaminated water. EPA believes that 

reservoirs and lakes provide such large dilution factors for 

releases of radionuclides that modeling these potential sources 

of contaminated water will provide release values much larger 

than those produced by modeling of ground water or river water 

and, therefore, is not necessary. 

Point sources of release are assumed in both the groundwater model and surface-water model. This assumption is made 

because such a source better represents a sudden, episodic 

release or spill as opposed to a chronic release from a waste 

site or other impoundment. Section B.l provides the general 

equation the Agency used to calculate release values for the 

consumption of contaminated drinking water while section B.2 

reviews a number of ground-water models examined by the Agency 

and describes in detail the advection-dispersion model chosen for 

calculation of a dilution factor to be used in the equation for 

calculation of release values based on water consumption. 

Section B.3 describes a surface water model for contamination of 

rivers from point source releases of radionuclides and explains 

the Agency's reasons for not using this model for determination 

of dilution factors and calculation of release values. 

B-l 
P.72 

B.l CALCULATION OF RELEASE VALUES FOR THE CONSUMPTION OF 

CONTAMINATED DRINKING WATER 

The release value calculated for the consumption of 

contaminated drinking water (DW) is directly proportional to the 

ingestion ALI and inversely proportional to the dilution factor, 

contact time, and water consumption rate of reference man. The 

method which the Agency has adopted for the calculation of 

release values based on the consumption of contaminated drinking 

water is summarized in equation (1). 

DW Release Value = ALI/[(10)*(DF)*(CT)*(WC)*(1 x IO6)] (l) 

where: 

ALI = annual limits if intake for ingestion (microcuries); 

10 factor to convert the annual limit of intake which is 

based on 5 rem dose-equivalent to a worker in a 

nuclear facility to the more conservative 0.5 rem for 

exposure to the general public; 

DF = dilution factor (liter"1); 

CT = contact time (days); 

WC = water consumption rate of reference man (2 liters per 

day); and 

1 x IO6 conversion factor between microcuries and curies. 

The ingestion ALIs used in the calculation are taken from 

ICRP's Publication 301 after conversion from becquerels to 

microcuries. Where more than one ALI was given for a particular 

radionuclide, the lowest value was used in the calculations. 

international Commission on Radiological Protection (ICRP), 

"Limits for Intakes of Radionuclides by Worker," Publication 30, 

Part 2, 1980. 

B-2 
P.73 

The dilution factor (DF) and contact time (CT) terms used in 

equation (1) for calculation of a drinking water release value 

based on the consumption of contaminated ground water are derived 

and more fully explained in section B.2 while section B.3 

explains the derivation of a dilution factor for contaminated 

river water. As described in section B.2, the dilution factor 

for ground-water consumption takes radioactive decay into account 

for the period of transport from the point of release to the 

point of exposure and the contact time term in equation (1) is 

modified for radioactive decay over the period of consumption. 

In determination of a dilution factor for consumption of 

contaminated river water, however, radioactive decay is not 

considered because the time of transport from the point of 

release to the point of consumption is very short. Additionally, 

in this case, radioactive decay during the period of consumption 

is ignored because this period is not well defined as it is in 

the scenario for consumption of contaminated ground water. 

B.2 GROUND-WATER TRANSPORT OF RADIONUCLIDES 

Two ground-water models for the purpose of calculating a 

dilution factor in equation (1), the advection-dispersion model 

and the simple dilution model, were examined in some detail by 

the Agency. Also, four other models developed for specialized 

purposes within the Resource Conservation and Recovery Act (RCRA) 

program were reviewed and compared to the selected advectiondispersion model. These models are described below. 

B.2.1 The Advection-Dispersion Model. 

The calculation of a dilution factor for a radionuclide 

release to ground water can be accomplished by assuming a release 

scenario that is reasonably conservative. In this calculation, 

it is assumed that the release is directly to ground water, which 

B-3 
P.74 

is a conservative assumption because it neglects migration 

through the unsaturated zone. The following assumptions are also 

made: 

o flow is uniform and steady (ground-water velocity =0.5 

meter/day); 

o the aquifer is homogeneous and isotropic; 

o the release is an instantaneous point source to the 

saturated zone; 

o at time zero, the concentration of radionuclide in the 

aquifer is zero; 

o the aquifer is of finite thickness and infinite extent 

(there are no boundaries close enough to affect the 

transport); and 

o the drinking water well is located 30 meters down 

gradient from the point of release. 

For an instantaneous point source located on the z axis in 

uniform steady flow (Exhibit B-l), the analytical solution of the 

transport equation is2: 

C

-3 M exp-

(4 7Tt)J/^(ExEyEz)V^Rdn 

(x-Ut)2 + _Y2 + __z2 + Xt 

4Ext 4Eyt 4Ezt 

(2? 

where: M = magnitude of the instantaneous release (1 Ci); 

Rd 

n 

X 

t 

= retardation factor; 

= effective porosity (0.1); 

= radioactive decay constant (0.693/t1/2) 

- time of travel from source to well 

(t - 30/(Vx/{riRd)); 

tl/2 = radionuclide half-life in days; 

2Carlsaw, H., Jaeger, J., "Conduction of Heat in Solids," Oxford 

University Press, London, 1959. 

B-4 
EXHIBIT B-l 

Scenario for Calculation of Ground-Water Transport 

3IOC VICW 

W«ll 

30« 

PLAM VICW 

Of riUiil- / 

/ 

Pt-UM* «t time 

9f»«ttr tfiM i»r« 

( 

well 

B-5 
P.76 

C = maximum radionuclide concentration; 

and Ex, Ey, E2, R^, and U are defined as: 

Ex = Dxx/%' Ey - Dyy/Rd,' Ez = Dz^Rd; 

U = Vx/nRd; R^j = 1 + (Pb)*(Kd/n); 

where: 

Dxx = longitudinal coefficient of dispersion; 

Dyy - Dzz

 = transverse coefficients of dispersion; 

Pj- = bulk density of the aquifer (1.5 gm/cm3) ; 

Vx = flow of the aquifer (0.5 meters per day). This 

value was chosen as a conservative flow rate for 

sand-containing aquifers by comparison to Table 

B-2 in the report referenced3. This table lists45 different saturated zone layers that contain 

sand and various other earth materials in 

different proportions. The smallest flow listed 

is 0.7 meters/year, while the largest is greater 

than 10,000 meters/year. The average flow is 625 

meters/year or abut 1.7 meter/day. A value of 0.5 

meters/day is conservative in that it prolongs 

contact time and leads to a lower (more 

conservative) Release Value; and 

K^ = the sorption coefficient in cm3/g (see Exhibit 

B-2 for a compilation of values used). 

Dispersion coefficients are defined by the following 

equations: 

Dxx " (a_.)*(Vx/n); Dyy = Dzz = (at)*(Vx/n); 

where: 

a! = longitudinal dispersivity (20 meters); 

a^ = transverse dispersivity (4 meters). 

3"Liner Location Risk and Cost Analysis model," Draft Report 

under Contract No. 68-01-6621, Office of Solid Waste, EPA, 

January, 1985. 

B-6 
P.77 

EXHIBIT B-2 

SORPTION COEFFICIENT VALUES 

SORPTION 

ELEMENT 

Actinium 

Aluminum 

Americium 

Antimony 

Argon 

Arsenic 

Astatine 

Barium 

Berkelium 

Beryllium 

Bismuth 

Bromine 

Cadmium 

Calcium 

Californium 

Carbon 

Cerium 

Cesium 

Chlorine 

Chromium 

Cobalt 

Copper 

Curium 

Dysprosium 

Einsteinium 

Erbium 

Ac 

Al 

Am 

Sb 

Ar 

As 

At 

Ba 

Bk 

Be 

Bi 

Br 

Cd 

Ca 

Cf 

C 

Ce 

Cs 

Cl 

Cr 

Co 

Cu 

Cm 

Dy 

Es 

Er 

COEFFICIENT. _yi 

1000 

0 

1000 

1 

0 

0 

0 

100 

700 

75 

10 

0 

50-100 

15 

0 

0 

2000 

2000 

0 

0 

2000 

0 

500 

0 

0 

0 

* SOURCE 

EPA 520/4-79-007C 

Assumption** 

Hajek (1966), Knoll (1965) 

(1969) 

EPA 520/6-78-007 

EPA 520/4-79-007C 

Assumption** 

EPA 520/4-79-007C 

Analogous to Sr (PNWL 8/2/86) 

EPA 520/4-79-007C 

EPA 520/4-79-007C 

EPA 520-4-79-007C 

Assumption** 

Estimate (PNWL 8/18/86) 

EPA 520/4-79-007C 

Assumption** 

Estimate (PNWL, 8/18/86) 

Rhodes (1957) Benson (1960) 

Letter Report RJS-ARCHO 

EPA 520/4-79-007C 

Assumption** 

EPA 520/6-78-007 

Assumption** 

EPA 520/6-78-007, Sheppard 

(1976) 

Assumption** 

Assumption** 

Assumption** 

B-7 
P.78 

ELEMENT 

Europium 

Fermium 

Fluorine 

Francium 

Gadolinium 

Gallium 

Germanium 

Gold 

Hafnium 

Holmium 

Hydrogen 

Indium 

Iodine 

Iridium 

Iron 

Krypton 

Lanthanum 

Lead 

Lutetium 

Magnesium 

Manganese 

Mendelevium 

Mercury 

Molybdenum 

Neodymium 

Neptunium 

Nickel 

Niobium 

Osmium 

Palladium 

Eu 

Fm 

F 

Fr 

Gd 

Ga 

Ge 

AU 

Hf 

Ho 

H 

In 

I 

Ir 

Fe 

Kr 

La 

Pb 

Lu 

Mg 

Mn 

Md 

Hg 

Mo 

Nd 

Np 

Ni 

Nb 

Os 

Pd 

SORPTION 

COEFFICIENT. % * 

500 

0 

0 

200 

500-1000 

0 

0 

0 

0 

600 

0 

0 

3 

0 

150 

0 

0 

4000 

0 

0 

0 

0 

0 

5 

500 

10 

100 

2000 

0 

50-100 

SOURCE 

Seme & Rai (1976) 

Assumption** 

Assumption** 

EPA 520/4-79-007C 

Chemical Analogy to Rare Earth 

(PNWL 8/18/86) 

Assumption** 

Assumption** 

Assumption** 

Assumption** 

EPA 520/4-79-007C 

EPA 520/6-78-007 

Assumption** 

Shallow Land Burial Program 

Assumption** 

EPA 520/4-79-007C 

Inert Gas (PNWL 8/18/86) 

Assumption** 

EPA 520/4-79-007C 

Assumption** 

Assumption** 

Assumption** 

Assumption** 

Assumption** 

EPA 520/4-79-007C 

Chemical Analog to Rare Earth 

(PNWL 8/18/86) 

Routson et al 1975, 76, 

Sheppard (1976) 

Estimate (PNWL 8/18/86) 

EPA 520/4-79-007C 

Assumption** 

Estimate (PNWL 8/18/86) 

B-8 
_PJ9 

SORPTION 

ELEMENT 

Phosphorus 

Platinum 

Plutonium 

Polonium 

Potassium 

Praseodymium 

Promethium 

Protactinium 

Radium 

Radon 

Rhenium 

Rhodium 

Rubidium 

Ruthenium 

Samarium 

Scandium 

Selenium 

Silicon 

Silver 

Sodium 

Strontium 

Sulfur 

Tantalum 

Technetium 

Tellurium 

Terbium 

Thallium 

Thorium 

P 

Pt 

Pu 

Po 

K 

Pr 

Pm 

Pa 

Ra 

Rn 

Re 

Rh 

Rb 

Ru 

Sm 

Sc 

Se 

Si 

Ag 

Na 

Sr 

S 

Ta 

Tc 

Te 

Tb 

Tl 

Th 

COEFFICII 

100-

:NT. K. 

0 

0 

-10000 

25 

35 

500-1000 

1000-

100-

-10000 

4000 

-10000 

0 

0 

0 

500 

0-500 

500-1000 

0 

10 

0 

50-100 

10 

100 

0 

0 

0 

50-100 

500-1000 

1000 

2 

-10000 

SOURCE 

Assumption** 

Assumption** 

EPA 520/6-78-007, A Shallow 

Land Burial Program 

EPA 520/4-79-007C 

EPA 520/4-79-007C 

Chemical Analogy to Rare Earth 

(PNWL 8/18/86) 

Benson (1960) Rare Earth 

EPA 520/4-79-007C 

EPA 520/6-78-007 

EPA 520/4-79-007C 

Assumption** 

Assumption** 

Chemical Analogy to Cs 

(PNWL 8/18/86) 

Rhodes (1957) 

Chemical Analogy to Rare Earth 

(PNWL 8/18/86) 

Assumption** 

Shallow Land Burial Program 

Assumption** 

Estimate (PNWL 8/18/86) 

EPA 520/4-79-007C 

Shallow Land Burial Program 

Letter Report RJS-ARCHO 

Assumption** 

Assumption** 

Shall Land Burial Program 

Estimate (PNWL 8/18/86) 

Chemical Analogy to Rare Earth 

(PNWL 8/18/86) 

EPA 520/4-79-007C 

EPA 5520-6-78-007 

B-9 
P.80 

SORPTION 

ELEMENT 

Thulium 

Tin 

Titanium 

Tungsten 

Uranium 

Vanadium 

Xenon 

Ytterbium 

Yttrium 

Zinc 

Zirconium 

Tm 

Sn 

Ti 

W 

U 

V 

Xe 

Yb 

Y 

Zn 

Zr 

COEFFICIENT. K$* 

0 

50-100 

0 

0 

1-50 

0 

0 

0 

500 

0 

2000 

SOURCE 

Assumption** 

Estimate (PNWL 8/18/86) 

Assumption** 

Assumption** 

Estimate (PNWL 8/18/86) 

Assumption** 

Inert Gas (PNWL 8/18/86) 

Assumption** 

Estimate (PNWL 8/18/86) 

Assumption** 

Rhodes (1957) 

For sorption coefficient values that are given in ranges, 

the lowest sorption coefficient was chosen for the ingestion 

Release Value calculation. 

** For these elements no K<j value has been obtained and a 

sorption coefficient of zero (Kd=0) was assumed (no 

retardation). 

SOURCES 

Bensen, D.W. 1960. Review of Soil Chemistry Research at 

Hanford. HW-67201. 

Environmental Protection Agency Rep. EPA 520/6-78-007. 

Ames, L. L. and Dhanpat Rai, "Radionuclide Interactions with 

Soil and Rock Media." 

Environmental Protection Agency Rep. EPA 520/4-79-007C. 

"Technical Support of Standards for High Level Radioactive 

Waste Management," Vol. C, Migration Pathways, 1979. 

Hajek, B. F. 1966. "Plutonium and Americium Mobility in 

Soils." BNWL-CC-925. 

Knoll, K. C. 1965. "Reaction of High Salt Aqueous Plus 

Organic Waste with Soil." BNWL-CC-313. 

B-10 
P.81 

Knoll, K. C. 1969. "Reactions of Organic Wastes in Soils. 

BNWL-860." 

Letter Report R. J. Seme - ARCHO 6/5/75, a letter written 

to Atlantic Richfield Hanford Company by w. Martin reporting 

some, at that time, new laboratory data. 

PNWL 8/18/86, Letter from Martin, W. to EMSI 8/18/86, 

reporting estimates of K^ for a Generic Sandy Sediment. 

Rhodes, D. W. 1957. "The Effect of pH on the Uptake of 

Radioactive Isotopes from Solution by a Soil." Soil Science 

Society of America Proceedings, 21:389-392. 

Routson, R. C , G. Jansen, and A. V. Robinson. 1976. 

"99T C Np

 an d 241Am Sorption on Two Subsoils from 

Differing Weathering Intensity Areas." BNWL-2000. Pt. 2, 

pp. 50-52. 

Seme, R. J. and Dhanpat Rai. 1976. "AdsorptionPrecipitation Behavior of Eu in Soils and Standard Clays." 

Agronomy Abstracts, p. 132. 

Shallow Land Burial Program - as yet unpublished results 

obtained on an ongoing DOE sponsored program. 

Sheppard, J. C., J. A. Kittrick, T. L. Hart. 1976. 

"Determination of Distribution Ratios and Diffusion 

Coefficients of Neptunium, Americium, and Curium in SoilAquatic Environments," RLO-221-T-12-2. 

B-ll 
P.82 

For this calculation, the aquifer is assumed to be thick 

enough so that the upper and lower boundaries do not 

significantly affect the vertical component of transverse 

dispersion as the contaminant migrates to the well. In view of 

the range of values presented by Codell and Duguid4, EPA belives 

these values for transverse and longitudinal dispersivity are 

reasonably conservative and appropriate for the adjustment of 

RQs.5 

The well is assumed to lie on the centerline of the plume 

(y = z = 0) and the maximum concentration at the well is given 

by: 

C - ____ _ ___ exp(-Xt) . (3) 

(4 TrtJ-V-fExEyEgjV^Rdn 

Substituting the relationships for Ex , Ey, Ez , and t int o 

Equation (3) gives: 

C = _ exp[(-0.693/t, / ? )(6)] 

R d n 

Simplification yields: 

C = M 

(1207T ) V - a t

1 / 2

 a_ n Rd 

exp(-4.2 Rd/ti/2) (5) 

4Till, J.E. Meyer, H.R. (Editors), "Radiological Assessment. 

Textbook on Environmental Analysis," NUREG/CR-3332, U.S. Nuclear 

Regulatory Commission, 1983. 

5Values for longitudinal and transverse dispersivity used for 

ground-water models developed for Resource Conservation and 

Recovery Act (RCRA) purposes are generally smaller because the 

equations were developed to evaluate risk while equations for RQ 

purposes are not directly risk related. Further discussion of 

these RCRA models can be found in this appendix. 

B-12 
P.83 

For a^ = 20 meters, a.^ = 4 meters, n = 0.1, M = 1 curie, and 

introducing a conversion fractor from cubic meters to liters (l x 

103), the maximum concentration at the well is calculated as: 

C - ,-r, _- ! _ exp(-4.2 RdAi/2) (6) 

(1207T )•*/ * (20) *-/*(*) (0.1) (Rd) (1X10J) ' 

C = 7.6 x IO"8 exp(-4.2 Rd/ti/2) liters"1. (7) 

Equation (7) gives the amount of dilution for a one curie 

release into an aquifer. The dilution factor (DF) for the 

aquifer is, therefore, defined as: 

DF - 7.6 x 10"8exp(-4.2 Rd/ti/2) liters"1. (8) 

The value of the retardation factor will affect not only the 

maximum concentration of the radionuclides found in the plume 

developed by the release but also the time required for the plume 

to reach and pass the well. When the sorption coefficient, Kd/ 

is equal to zero, the retardation factor is equal to one. When 

the sorption coefficient becomes larger, however, the retardation 

factor increases rapidly (e.g., when Kd = 1/ Rd ~

 16 ) • As Kd 

increases, then, a longer period of time is required for the 

radionuclide to reach and pass the well. When radioactive decay 

is considered in this equation and the retardation factor is 

greater than one, it has the effect of "removing" a large portion 

of the radionuclides before they can be ingested. As a result, 

the calculated release value, when the retardation factor is 

greater than one, is significantly larger than the release value 

when the retardation factor is equal to one and, in fact, becomes 

much larger in comparison with the other release values 

calculated for the other exposure pathways. It is recognized, 

therefore, that the ground-water ingestion release value 

B-13 
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a/b = a/c = a]/a-t = 20/4 = 5. 

Therefore, 

b = a/5, c = a/5, 

and 

1 = (4/3) *(7T )*(a3/25)*(7.6 X IO"5) . (10) 

Solving for a gives: 

a - 43 meters, 

and the time required for the ellipsoidal plume to pass the well 

is given by: 

Contact Time (CT) = a/(Vx/n) = 9 days. (ll) 

Because the time available for consumption of contaminated water 

is the same as the period of time the contamination is in 

contact with the well, the contact time (CT) is 9 days. 

In order to consider decay over the period of ingestion, it 

is recognized that an individual will ingest smaller quantities 

of radioactivity at times that are succesively more distant from 

the time that the radionuclide first arrives at the point of 

exposure, the drinking water well. Accordingly, radioactive 

decay over the period of exposure was taken into account by 

modifying the contact time as follows: 

1 - expf- X CT). 

X 

B-15 
The Ground-Water Ingestion Release Value is calculated by 

use of equation (1) and substituting in the modified expression 

for contact time as summarized in equation (12) below: 

Ground-water 

Ingestion = ALI . (12^ 

Release Value [lO]*[DF]*[WC]*[l-exp(- XCT)/X ]*[1 x IO6] 

Where: 

ALI = Annual Limits of Intake for ingestion 

(microcuries); 

10 converts the 5 rem occupational exposure limit to 

the more conservative 0.5 rem exposure limit for 

the general public; 

x = 0.693/t1/2; 

tl/2

 = radionuclide half-life (days); 

DF = dilution factor [7.6 x 10~8 exp(-4.2 Rd/tl/2) 

liters"1]; 

Rd = retardation factor (1); 

WC = water consumption rate of "Reference Man" (2 

liters/day); 

CT = contact time (9 days); and 

1 x IO6 converts microcuries to curies. 

Substituting the values for DF, WC, Rd, and CT gives the 

following expression for the ground-water ingestion Release 

Value: 

Ground-water 

Ingestion = ALI . (13; 

Release Value [2.2]*[exp(-4.2/t1/2)]*[t1/2-t1/2exp(-6.2/t1/2)] 

B-16 
P.87 

B.2.2 The Simple Dilution Model. 

The Nuclear Regulatory Commission suggested a simple 

dilution model for the calculation of Release Values based on 

ground-water transport. This model was developed in order to 

determine the maximum concentrations for on-site disposal of low 

level nuclear waste and to identify sites suitable for the 

disposal of such waste. The Commission's goal in both these 

cases is to minimize the risk to the public for exposure via the 

ground water to releases of radioactive material. Although this 

approach may be appropriate for the minimization of risk, it 

appears inappropriate for the determination of RQs which simply 

act as triggers for notification of a release of a hazardous 

substance. Some of the assumptions made by the Nuclear 

Regulatory Commission for their calculations using the simple -

dilution model are shown below.7 

o Ground-water flow rates are between 0.0005 and 0.03 

meters/day. 

o Longitudinal dispersivities are between 0.05 and 0.1 

meter. 

o Transverse dispersivities are zero. 

o Pumping rates can vary between 7700 cubic meters/year 

and 2,000,000 cubic meters/year. 

o Water consumption is 2 liters/day for an individual. 

Using these assumptions, the aquifer resembles a very slow 

flowing pipeline between the point of release and the well. The 

flow occurs at such a rate that the entirety of the release is 

pumped from the well over a period of one year. The contact time 

(CT) is, therefore, 365 days. Ignoring radioactive decay and 

7Oztunali, O.I., Roles, C.W., "DeMinimis Waste Impacts 

Analysis Methodology," NUREG/CR-35 85, February, 1984. 

B-17 
P.88 

using a pumping rate of 7700 cubic meters per year as suggested 

by the Nuclear Regulatory Commission, a dilution factor (DF) can 

be calculated: 

DF = 1/7700 m3 - 1.3 x IO"4 m"3 - 1.3 x IO"7 liter"1. 

Using these figures and once again ignoring radioactive 

decay, a Release Value (RV) in curies can be calculated from an 

ALI in microcuries by use of equation (1). 

RV o ALI/[(10)*(1.3 x 10"7/liter)*(2 liter/day)*(365 day)* 

(1 x IO6 uCi/Ci)]; 

RV = ALI/949. 

Release Values for ingestion calculated in this way would be 

about 70 times smaller than those calculated by the advectiondispersion model ignoring radioactive decay and similarly smaller 

including factors for radioactive decay. 

B.2.3 Other Ground-Water Models 

The EPA's Office of Solid Waste uses several ground-water 

models in implementing the Resource Conservation and Recovery Act 

(RCRA). Although other models are used within the RCRA program, 

the following four have been analyzed and compared to the groundwater ingestion model: 

o The Comparative Risk Assessment Model (CRAM) used to 

compare the human health risks and costs of various 

combinations of hazardous waste streams, environmental 

settings, and waste treatment technologies; 

o The Liner-Location Risk and Cost Analysis Model used to 

estimate the human health risks of land disposal 

facilities of different designs in different 

environmental settings; 

B-18 
o The Threshold Model used in determining the need to ban 

or restrict hazardous waste from land disposal; and 

o The Vertical and Horizontal Spread (VHS) Model used in 

analyzing ground-water transport issues associated with 

delisting petitions (i.e., petitions to remove a 

substance from RCRA's hazardous substance list). 

The following discussion compares those four RCRA models to 

the RQ ground-water model in terms of: (1) the basic equations 

used in each model; and (2) values for the input variables used 

in the equations. 

Comparison of Model Ecruations 

All simple ground-water transport models — including the 

transport models used in the RQ adjustment methodology/ the CRAM, 

the Liner Location Model, the Threshold Model, and the VHS Model 

— are based on the same laws of physics and, as such, are based 

on the same basic transport equation. The only difference in 

the models' equations is the release scenario used in developing 

the analytical solution to the transport equation. These release 

scenarios vary in two respects. First, the configuration of the 

contaminant source can vary; it can be a point source, a line 

source, or a plane source. Second, the contaminant that is being 

modeled can be released in different time frames; it can be 

released instantaneously, continuously, or at a variable rate. 

Everything else being equal, all of the ground-water models 

considered here will give different results only because their 

equations are based on different source configurations and 

different contaminant release rates. The source configuration 

and contaminant release rates assumed in each of the models are 

shown in Exhibit B-3. 

B-19 
P.90 

EXHIBIT B-3 

SOURCE CONFIGURATIONS AND CONTAMINANT RELEASE 

RATES ASSUMED IN THE RCRA AND RQ MODEL EQUATIONS 

Model 

Contaminant Source 

Configuration 

Contaminant 

Release Rates 

RQ Model 

CRAM 

Liner-Location Model 

Threshold Model 

VHS Model 

point source 

point source 

plane source 

plane source 

plane source 

instantaneous 

release 

continuous release 

time variable 

release 

time variable 

release (Gaussian) 

continuous release 

Source: ICF Analysis 

The selection of instantaneous release for the RQ model was 

based on the consideration that the highest ground-water 

concentration will be achieved when the source is released 

instantaneously rather than continuously or at some variable 

rate. For example, a well 30 meters downgradient from the point 

of release would experience a higher concentration of radioactivity if 1 curie was released all at once rather than a 

little bit at a time over a prolonged period. On the other hand, 

an instantaneous release versus a prolonged release will result 

in ground-water contamination that will pass beyond a well more 

quickly (i.e.. the contact time is shorter for an instantaneous 

release). For a prolonged release, the contamination will be 

found in smaller concentrations but will persist around a nearby 

well for a longer period of time. 

B-20 
P.91 

In comparing the different contaminant source configurations, neither a point nor a plane source is necessarily always 

more conservative than the other. A point source assumes that 

the entire release, assumed to be 1 cur_.'a in the RQ groundwater model, is at the outset concentrated into a single point 

and then allowed to disperse as it flows downgradient to the 

point of exposure. In contrast, a plane source assumes that the 

total release is distributed throughout a plane of a specified 

length and width. Whether one is more conservative than the 

other depends on the dimensions of the plane in relation to the 

dimensions of the aquifer, and on the distance from the point of 

release to the point of exposure. A point source is thought to 

be more appropriate for the purpose of developing an RQ because 

it best represents a sudden, episodic release or spill. A plane 

source is more appropriate for modeling chronic releases from a 

surface impoundment or landfill. 

Comparison of Values for Input Variables 

The primary input variables in the RQ ground-water model 

are: 

o a retardation factor, which takes into account how much 

a contaminant is retarded (through sorption by soil and 

other mechanisms) relative to the transporting water 

mass; 

o ground-water velocity; 

o saturated zone thickness; 

o porosity, which refers to the amount of openings or 

holes in a soil or rock; 

o longitudinal dispersivity, which reflects the extent of 

dispersion of a contaminant at right angles to the 

direction of ground-water flow; and 

o the distance to the nearest water supply well. 

B-21 
P.92 

The values used for the variables in the RQ ground-water 

model, as well as the values used in the RCRA ground-water 

models, are presented in Exhibit B-4. As shown in this exhibit, 

all but one model (the VHS model) take into account contaminant 

retardation. 

As also shown in Exhibit B-4, the values used for velocity, 

aquifer thickness, and porosity in the RQ ground-water model are 

in the range of those commonly used by the RCRA models. However, 

the values for dispersivity (both longitudinal and transverse) 

used in the RQ model are significantly higher than those used in 

the RCRA models. 

The values of longitudinal and transverse dispersivity 

reported in the literature vary widely. Dispersivity values have 

been obtained for different soil types through field 

measurements, laboratory experiments, and from the calibration of 

numerical models (i.e., calibration of models to match observed 

field data). In general, out of these three ways to determine 

values for dispersivity, values measured in the laboratory are 

the lowest, field measured values are generally intermediate in 

size, and the model derived values are usually the highest. 

Laboratory measured values of dispersivity are often so low that 

they are frequently considered unrealistic; model derived values 

are considered more realistic than those measured in the 

laboratory, but not as realistic as those measured in the field. 

Exhibit B-5 presents fields measured values and model 

derived values of dispersivity for alluvial aquifers (i.e., 

deposits composed of particles of gravel, sand, silt, or clay 

that are not bound or hardened). 

B-22 
EXHIBIT B-4 

VALUES OF INPUT VARIABLES USED IM THE RCRA AHD 

RQ GROUND-WATER NOOELS 

Model Retardation a/ 

Ground-Water 

Velocity 

(m/day) 

Aquifer 

Thickness 

(m) 

Porosity 

(dimensionless) 

Longitudinal 

Dispersivity 

(m) 

Transverse 

Dispersivity 

(m) 

Distance 

to Well 

(m) 

RQ Model 

CRAM 

yes 

yes 

Liner-Location yes 

Threshold Model yes 

VHS Model no 

0.5 

<25 

0.003-28 

<25 

N/A d/ 

20 

53 b/ 

0.1 

0.35-0.56 

30 

3-560 

thick 

enough 

so as to 

not impede 

dispersion 

0.01-0.3 

0.3-0.6 

N/A d/ 

20 

1.8-2.8 0.6-1 

0.6 

1.7 

0.2 

30 

50 c/ 

60 c/ 

50 cl 

305 

a/ Values for retardation factors are not given; instead the table indicates whether the model considers retardation. 

b/ In CRAM, saturated aquifer thickness has an exponential probability distribution with a mean of 53. 

c/ These are the shortest distances to wells used by the models: the dispersivity values reported, which are dependent on distance, are 

based on these minimum distances, 

d/ Not applicable; velocity and porosivity are not used in the VHS model. 

B-23 
P.94 

EXHIBIT B-5 

FIELD MEASUREMENT AND MODEL CALIBRATION VALUES 

FOR DISPERSIVITY FOR ALLUVIAL AQUIFERS 

Field Measurements ~ Model Calibration Values 

Transverse Longitudinal Transverse 

Dispersivity Dispersivity Dispersivity 

Setting (m) (m) (m) 

Chalk River, 

Ontario 

Lyons, France 

Alsace, France 

Barstow, CA 

Rocky Mountain 

Arsenal 

Arkansas River 

Valley 

California 

Sutter Basin, < 

Longitudinal 

Dispersivity 

(m) 

0.034-0.1 

0.1-0.5 

12 

15.2 

CA 

15 

61 

30.5 

r-l 

18 

30.5 

30.5 

30.5 

80-200 

9.1 

9.1 

8-20 

Source: Tables 4.1 and 4.2 in Codell, R. and Duigid, J., "Transport 

of Radionuclides in Groundwater," Chapter 4, Radiological 

Assessment. Till, J., and Meyer, H., eds., U.S. Nuclear 

Regulatory Commission, September 1983. 

B-24 
In comparing the dispersivity values used in the RQ model to 

the values in Exhibit B-5, the RQ model's values are on the high 

side for field measured values and on the low side for model 

calibration values. EPA considers the dispersivity values used 

in the RQ model to be realistic for an alluvial aquifer. The 

dispersivity values used in the RCRA models are generally on the 

low side of the field measured values, and significantly lower 

than the values obtained from the model calibrations. 

The models developed by the EPA Office of Solid Waste for 

application to RCRA are risk based and as such are believed to be 

more conservative than necessary for development of reportable 

quantities which act as a trigger for notification of a release 

of a hazardous substance. For this reason, the Agency has 

decided to use the advection-dispersion model for determination 

of Release Values based on a ground-water ingestion scenario. 

B.3 SURFACE WATER TRANSPORT OF RADIONUCLIDES 

Surface water used for drinking purposes in the United 

States generally comes from lakes, reservoirs, or rivers. Lakes 

and reservoirs are similar in that they are generally large 

bodies of water with relatively low flow rates when compared to 

rivers. Because of their size, dilution factors for 

radionuclides in lakes and reservoirs are expected to be much 

larger than those for rivers, and the Agency has chosen to model 

consumption of contaminated surface water with reference to small 

rivers in preference to lakes or reservoirs. 

B.3.1 Calculation of a Dilution Factor for River Water 

Equation (1) can be used to calculate a drinking water 

Release Value for river water if a dilution factor for this 

source of water can be determined. Equation (14) has previously 

B-25 
P.96 

been recommended by the Agency8 for the calculation of downstream 

concentrations of pollutants after release from a point source. 

Cx = {[Q]*[exp(- Xx/u)]}/F (14) 

where: 

Cx = maximum contaminant concentration 30 meters 

downstream (Ci/liter); 

Q = contaminant release rate (Ci/day); 

F = surface water flow rate (liter/day); 

X = radioactive decay constant (0.693/two, sec-1. For 

the reasons discussed above, radioactive decay is 

ignored in this calculation and the radioactive halflife, tw2' is considered to be infinite); 

x = distance from point of release to point of exposure 

(30 meters); and 

u = mean stream velocity (0.64 meter/sec). 

In applying this equation the following assumptions are made: 

o the release is an instantaneous point source and the 

river is homogeneous and isotropic; 

o prior to the moment of release, the concentration of 

radionuclide in the river is zero; 

o contaminant and river water mix completely and 

instantaneously and there is no longitudinal 

dispersion; 

o exposure occurs 3 0 meters downgradient from the point 

of release; 

8U.S. Environmental Protection Agency, Office of Emergency and 

Remedial Response, "Superfund Exposure Assessment Manual," Final 

Draft, prepared by Versar, Inc., September 22, 1987. 

B-26 
P.97 

o a small river is assumed with a flow rate of 1 x IO9 

liters per day (about 400 cubic feet per second) and a 

velocity of about 0.64 meters per second9; 

o removal of the released radionuclide by other processes 

(e.g., settling, vaporization) is ignored; and 

o radioactive decay during transport is neglected because 

the transport time to a point 30 meters downstream is 

short and decay over this short period of time is 

negligible for all but a handful of radionuclides. 

With the radioactive decay constant set to zero (i.e., no 

decay is considered) equation (14) simplifies to: 

Cx = Q/F. (15) 

Using a value of 1 x IO9 liters per day for F in equation (15) is 

reasonably conservative because only about 15 percent of surface 

water in the United States flows at a rate slower than this 

value10. Because concentration and surface water flow rate are 

inversely proportional, a higher flow rate would lead to a lower, 

less conservative concentration. Substituting the source term, l 

curie, for Q in equation (15) gives: 

Cx = (1 Ci/day)/(l x IO9 liter/day) (16) 

Cx - 1 x 10~9 Ci/liter. (17) 

Equation (17) gives the amount of dilution for a one curie 

release into a small river. The dilution factor (DF) for use in 

9U.S. Environmental Protection Agency, Office of Solid Waste, 

"The RCRA Risk-Cost Analysis Model Phase III Report," prepared by 

ICF, Inc., March 1, 1984. 

10"Determination of Harmful Quantities and Rates of Penalty for 

Hazardous Substances," EPA-440/9-75-005, Volumes a-d, January, 

1975. 

B-27 
3.98 

calculating surface water release values is, therefore, defined 

as: 

DF = 1 x IO"9 liter"1. (18) 

Radioactive decay over the period of ingestion is ignored 

and a 1 day contact time (CT) is used in equation (1). The 

Agency believes that it is appropriate to ignore radioactive 

decay under these circumstances because, as is the case for 

radionuclide inhalation, it is not possible to establish exact 

bounds on the range of exposure periods. An individual could 

consume a daily quantity of water over a few minutes, allowing 

little decay for a short-lived radionuclide, or over the period 

of an entire day. 

Substituting values for DF, CT, and WC into equation (1) and 

solving for the drinking water release value based on consumption 

of contaminated river water gives equation (19): 

River-water 

Ingestion = ALI . (19) 

Release Value 0.02 

Comparison of release values calculated by use of equation (19) 

and those release values calculated for ground water ingestion, 

inhalation, consumption of contaminated vegetables, and direct 

exposure shows that in no case is the river-water ingestion 

release value the lowest of the calculated release values and no 

RQs are determined by use of equation (19). For this reason, the 

Agency used the equation calculating ground-water ingestion 

release value [equation (13)] to model ingestion of contaminated 

drinking water. 

B-28 
P.99 

APPENDIX C 

MODELING THE INGESTION OF CONTAMINATED 

FOODSTUFFS 

A number of models have been developed to describe the 

transfer of radionuclides to various foodstuffs and then to man 

after an atmospheric radioactive release.1 These models 

typically begin with an estimate of the radionuclide air 

concentration above the food crop or pasture and subsequently 

calculate the radionuclide concentration in and on the food crop 

or forage. The level of contamination depends upon many factors 

including the rate at which the radionuclide is deposited, the 

fraction retained by the plant leaf, the areal density of the 

crop, and the transfer rate between soil and crop. Equations 

relating these variables generally include compartments 

describing mechanisms for removal of radionuclides from crops 

through weathering and radioactive decay. In addition, models 

have been developed which describe the transport of radionuclides 

to man through milk (the so-called air-grass-cow-milk-man 

pathway), meat, and vegetable crops or forage contaminated by 

contact with contaminated irrigation water. The Agency has 

analyzed these pathways for the purpose of calculating RQs and 

describes the results of these analyses in this Appendix. 

EPA has decided to use release values calculated as a result 

of airborne contamination of leafy vegetables as a component in 

the determination of reportable quantities for radionuclides. 

This route was chosen in preference to the irrigation pathway 

because, as is shown in the discussion of this pathway, the 

amount of radionuclide provided to man via irrigation of 

vegetables with ground water will, under the modeling conditions 

^-Nair, S., "Models for the Evaluation of Ingestion Doses 

From the Consumption of Terrestrial Foods Following an 

Atmospheric Radioactive Release." Central Electricity Generating 

Board, Berkeley Nuclear Laboratories, England, April, 1984. 

C-l 
P.100 

analyzed, always be less than that provided by direct consumption 

of the contaminated ground water. Milk and/or meat contamination 

can be an important pathway for radionuclide consumption by man 

after an airborne or waterborne release of radionuclides. These 

pathways, however, were not chosen for the calculation of release 

values because radionuclide concentrations found in meat and milk 

are highly dependent upon element specific transfer factors 

between the forage or water and the animal products. These 

transfer factors are available for only a few elements and the 

equations, therefore, can only be used for a fraction of 

radionuclides. 

Section C l documents the equation used by the Agency to 

calculate release values for food ingestion. Section C.2 

presents in detail the application of this model to airborne 

deposition of radionuclides on vegetable crops and discusses the 

irrigation model investigated by the Agency. Section C.3 briefly 

describes the approaches considered by the Agency for evaluation 

of contaminated meat and milk. 

C l THE FOOD INGESTION MODEL 

The size of the release in curies necessary to provide a 500 

millirem exposure to a member of the general public through the 

consumption of contaminated vegetables is the Vegetable Ingestion 

Release Value. This quantity is directly proportional to the 

annual limit of intake for ingestion and inversely proportional 

to the concentration on and in the vegetables, the daily rate of 

food consumption, the contact time and the release fraction for 

the radionuclide. This relationship is summarized in equation 

(1). 

Vegetable Ingestion 

Release Value = ALI/[(10)*(DF)*(FC)*(CT)*(R)*(1 x IO6)] (1) 

(curies) 

C-2 
_p,1 

where: 

ALI = annual limit of intake for ingestion (microcuries); 

10 factor to convert the annual limit of intake which is 

based on 5 rem dose-equivalent to a worker in a 

nuclear facility to the more conservative 0.5 rem for 

exposure to the general public; 

DF = dilution factor - the concentration of radionuclide in 

and on the vegetation per curie of radionuclide 

released to the atmosphere (Ci/kg per Ci released or 

1/kg - derivation of this term is described in Section 

C.2 below); 

FC = food consumption (i.e., leafy vegetable) of reference 

man (0.175 kg/day - U.S. Nuclear Regulatory 

Commission, Regulatory Guide 1.109, October, 1977. 

Page 40.); 

CT - contact time, or the number of days over which the 

contaminated vegetables are ingested (derivation of 

this term is described below); 

R = airborne release fraction (see Appendix A for a 

discussion of release fractions); and 

1 x IO6 conversion factor between microcuries and curies. 

The ingestion ALIs used in the calculations are taken from 

ICRP's Publication 302 after conversion from becquerels to 

microcuries. Where more than one ingestion ALI was given for a 

particular radionuclide, the lowest value was used in the 

calculations. 

C.2 DETERMINATION OF THE DILUTION FACTOR 

Two approaches for modeling the concentration of 

radionuclides in and on vegetable crops after an airborne release 

were evaluated. The first used an equation published by the 

Nuclear Regulatory Commission and the second a similar equation 

international Commission on Radiological Protection (ICRP), 

"Limits for Intakes of Radionuclides by Workers," Publication 30, 

Part 2, 1980. 

C-3 
P.2 

developed by the National Council on Radiation Protection and 

Measurements (NCRP) and recommended by them to model the effects 

of continuous or intermittent releases of radioactive material to 

the environment. 

C.2.1 The Nuclear Regulatory Commission Model3 

The Nuclear Regulatory Commission model estimates the 

concentration of radionuclides on and in vegetation produced by 

deposition onto the plant foliage from air and by uptake from 

activity initially deposited on the ground. The model is valid 

for particulate radionuclides except tritium and carbon-14. The 

Commission provides values for the model's various input 

parameters to allow the use of the equation for different 

purposes such as estimating concentrations in produce consumed by 

man; in leafy vegetables consumed by man; or in forage consumed 

by animals and converted to meat or milk consumed by man. The 

equation contains a term for the deposition rate of a 

radionuclide (d^), which is calculated by reference to a second 

Regulatory Guide4 and which uses atmospheric dispersion estimates 

to derive the air concentration at various distances downwind 

from a release. 

EPA used the Nuclear Regulatory Commission's model for the 

development of proposed RQs for radionuclides; however, after a 

re-evaluation of the Nuclear Regulatory Commission and NCRP 

models, EPA decided to use the NCRP model for development of the 

final RQs. This change was made mainly because it was determined 

3Nuclear Regulatory Commission, "Calculation of Annual Doses 

to Man From Routine Releases of Reaction Effluent for the Purpose 

of Evaluating Compliance with 10 CFR Part 50, Appendix I." 

Regulatory Guide 1.109, October, 1977. 

4Nuclear Regulatory Commission, "Methods for Estimating 

Atmospheric Transport and Dispersion of Gaseous Effluents in 

Routine Releases from Light-Water-Cooled Reactors." Regulatory 

Guide 1.111, July, 1977. 

C-4 
P.3 

that the assumptions and calculational techniques used to develop 

the Commission's methodology make it unsuitable for application 

to a distance of 30 meters from an assumed point source. The 

Commission's approach was developed specifically for 

consideration at nuclear power plants with particular release 

characteristics and relatively large distances (i.e., several 

hundred meters and beyond) to a potential receptor of interest. 

Accordingly, EPA concluded that extrapolation of relative 

deposition rates presented in Regulatory Guide 1.111 to a distnce 

of 30 meters would not be accurate. 

C.2.2 The NCRP Model5 

The NCRP model was designed to address continuous or 

intermittent releases of radioactive material to the environment 

and aid in the design or redesign of facilities handling 

radionuclides so that their projected emissions can be compared 

with environmental standards. The model is very similar to the 

Nuclear Regulatory Commission model, but incorporates a term for 

the deposition rate of radionuclides from air to crops that is 

generally believed to be more suitable than the Commission's 

model for the 30-meter distance used in this analysis. The 

equation allows for the time period that crops are exposed to 

contamination during the growing season and therefore can be 

applied to episodic releases. Several assumptions are made in 

applying this model to the specific circumstances of release 

considered here, and include: 

o the release is an episodic release and all radionuclides which are going to become airborne and be 

subject to deposition on or near a crop are released 

in one day or less; 

5"Screening Techniques for Determining Compliance with 

Environmental Standards: Releases of Radionuclides to the 

Atmosphere." NCRP Commentary No. 3, National Council on 

Radiation Protection and Measurement, March 31, 1986. 

C-5 
P.4 

o the exposed vegetable crop is located 3 0 meters 

downwind from the point of release and the contaminated 

food is consumed on a daily basis by an individual for 

60 days (the length of the growing season); and 

o radioactive decay which may occur between the time of 

release and the time of deposition on the vegetables is 

conservatively assumed to be zero (i.e., X^ = 0) 

because the time period of release could be as short as 

a few seconds or as long as one day, and is undefined. 

The NCRP equation along with an explanation of the terms is 

shown below: 

C = V C •-"

 lexp("XEte) • Bv 1"«P(- W 

'v d aiiirr \t~~~ |Y A- P A- (2) 

where: 

Cv = concentration of radionuclide in and on vegetation 

(Ci/kg); 

cair = concentration of radionuclides in air at the location 

of growing vegetables (8.4 x IO"7 Ci/meter3), 

where Cair = (radionuclide release rate)*(X/Q); 

X/Q = atmospheric relative concentration (8.4 x 10~7 

day/meter3, see Appendix A) ; 

V<j = deposition velocity for wet and dry deposition 

(1000 meter/day); 

fR = intercept fraction, the fraction of deposited 

activity intercepted and retained by edible portions 

of the crop (0.25, dimensionless); 

XE . = effective decay constant for removal of the 

radionuclide deposited on vegetation (1/day), where 

XE = Xi + Xw ; 

Xi = radioactive decay constant (1/day) = 0.693/tw2

 = °' 

Xw = weathering decay constant (1/day) = 0.693/tw; 

tl/2 = radioactive decay half-life for the individual 

radionuclide (day, radioactive decay occurring 

during the period of release and transport to the 

crop is ignored); 

C-6 
P.5 

tw = weathering half-life (14 days); 

te = time period of above-ground crop exposure to 

contamination during the growing season (1 day); 

Y - standing crop biomass of edible portion of crop at 

harvest (2 kg/meter2); 

By = concentration ratio for the transfer of the element 

to the edible portion of a crop from dry soil 

(dimensionless and radionuclide specific, see 

Exhibit C-l for a compilation of these values); 

XB = the effective rate constant for removal of 

radionuclide from soil (1/day), where 

XB = Xi + X H L ; 

XH L = rate constant for removal of radioelement from soil 

by harvesting and leaching (2.7 x 10~5 day"1); 

tD = period of deposition in soil (1 day); and 

P = areal density for the effective root zone in soil 

(240 kg/meter2). 

Substituting the appropriate values into equation (2) and 

solving gives: 

Cv == (1 x IO"4 + 3.5 x IO"6 By) Ci/kg. (3) 

This becomes a dilution factor (DF) through division by the 

source term, 1 curie: 

DF = (1 X IO"4 + 3.5 X IO"6 By) kg"1. (4) 

The dilution factor, used in equation (1) for the 

calcualtion of vegetable ingestion release values, represents the 

concentration of radionuclide in and on vegetation per curie of 

radionuclide release to the atmosphere; it is in units of Ci/kg 

per Ci, or kg"1. 

C-7 
P.6 

The Agency assumes that the contaminated vegetables are 

consumed on a daily basis during the growing season and are not 

stored. The growing season is nominally considered to be 60 days 

(t) and thus would become the contact time (CT) in equation (1) 

if one were to ignore radioactive decay and removal of 

radionuclide from the vegetation by weathering processes. In 

fact, because radionuclides are removed by both decay and 

weathering in an exponential fashion, there is an "equivalent" 

contact time that depends upon the length of the growing and 

consuming season (t) and the rate of loss due to decay and 

weathering. This equivalent contact time is calculated in the 

following way: 

1 - exp (- X E t) 

CT = . (5) 

XE 

Substitution for X E gives: 

1 - exp [-( Xi + Xw)*t] 

CT - . (6) 

Xi

 + Xw 

Substitution for Xi and X w yields: 

1 - exp{-[(0.693/t1/2) + (0.693/tw)]*[t]} 

CT = . _ . (7) 

(0.693/t1/2) + (0.693/tw) 

Using a value of 60 days for t and a value of 14 days for the 

weathering half life (tw ), equation (7) simplifies to: 

1 - exp-[(41.6/t1/2) + 3] 

CT -= _ . (8) 

(0.693/t1/2) + 0.0495 

C-8 
P.7 

Substituting appropriate values for DF and FC into equation 

(1) gives: 

Vegetable Ingestion ALI (ingestion) 

Release Value = , (9) 

(curies) (175 + 6.1 _v)*(R)*(CT) 

where CT is calculated using equation (8). 

Application of this equation to those radionuclides for 

which ALIs are available produces the food ingestion release 

values shown in Appendix E. 

C-9 
P.8 

EXHIBIT C-l 

SOIL TO PLANT CONCENTRATION FACTORS (Bv) 

Bv 

0.0035 

0.0040 

0.0055 

0.20 

0 

0.040 

1.0 

0.1 5 

0.00 1 

0.010 

0.035 

1.5 

0.5 5 

3 . 5 

0.00 1 

0.010 

0.080 

70 

0.0075 

0.020 

0.40 

0.00085 

0.010 

0.001 

0.010 

0.010 

0.001 

0.060 

0.030 

ELEMENT 

Actinium 

Aluminum 

Americium 

Antimony 

Argon* 

Arsenic 

Astatine 

Barium 

Berkelium** 

Beryllium 

Bismuth 

Bromine 

Cadmium 

Calcium 

Californium** 

Cerium 

Cesium 

Chlorine 

Chromium 

Cobalt 

Copper 

Curium 

Dysprosium 

Einsteinium** 

Erbium 

Europium 

Fermium** 

Fluorine 

Francium 

SYMBOL 

AC 

Al 

Am 

Sb 

Ar 

As 

At 

Ba 

Bk 

Be 

Bi 

Br 

Cd 

Ca 

Cf 

Ce 

Cs 

Cl 

Cr 

Co 

Cu 

Cm 

Dy 

Es 

Er 

Eu 

Fm 

F 

Fr 

C-10 
P.9 

EXHIBIT C-l 

SOIL TO PLANT CONCENTRATION FACTORS (Bv) 

Sv 

0.010 

0.0040 

0.40 

0.40 

0.0035 

0.010 

0.010 

0.0040 

0.15 

0.055 

0.0040 

0 

0.010 

0.045 

0.010 

1.0 

0.25 

0.0010 

0.90 

0.25 

0.010 

0.10 

0.060 

0.020 

0.015 

0.15 

3.5 

0.095 

0.00045 

ELEMENT 

Gadolinium 

Gallium 

Germanium 

Gold 

Hafnium 

Helium 

Holmium 

Indium 

Iodine 

Iridium 

Iron 

Krypton* 

Lanthanum 

Lead 

Lutetium 

Magnesium 

Manganese 

Mendelevium** 

Mercury 

Molybdenum 

Neodymium 

Neptunium 

Nickel 

Niobium 

Osmium 

Palladium 

Phosphorus 

Platinum 

Plutonium 

SYMBOL 

Gd 

Ga 

Ge 

AU 

Hf 

He 

Ho 

In 

I 

Ir 

Fe 

Kr 

La 

Pb 

Lu 

Mg 

Mn 

Md 

Hg 

Mo 

Nd 

Np 

Ni 

Nb 

OS 

Pd 

P 

Pt 

Pu 

C-ll 
P.10 

EXHIBIT C-l 

SOIL TO PLANT CONCENTRATION FACTORS (Bv) 

ELEMENT SYMBOL Bv 

Polonium Po 0.0025 

Potassium K l.o 

Praseodymium Pr 0.010 

Promethium Pm 0.010 

Protactinium Pa 0.0025 

Radium Ra 0.015 

Radon* Rn o 

Rhenium Re 1.5 

Rhodium Rh 0.15 

Rubidium Rb 0.15 

Ruthenium Ru 0.075 

Samarium Sm 0.010 

Scandium Sc 0.0060 

Selenium Se 0.025 

Silicon si 0.35 

Silver Ag 0.40 

Sodium Na 0.075 

Strontium Sr 2.5 

Sulfur S 1.5 

Tantalum Ta 0.010 

Technetium Tc 9.5 

Tellurium Te 0.025 

Terbium Tb 0.010 

Thallium Tl 0.0040 

Thorium Th 0.00085 

Thulium Tm 0.010 

Tin Sn 0.030 

C-12 
P.11 

I 

I 

I 

i 

i 

i 

i 

i 

i 

i 

I 

i 

i 

i 

i 

l 

i 

I 

i 

EXHIBIT C-l 

SOIL TO PLANT CONCENTRATION FACTORS (Bv) 

ELEMENT 

Titanium 

Tungsten 

Uranium 

Vanadium 

Xenon* 

Ytterbium 

Yttrium 

Zinc 

Zirconium 

SYMBOL 

Ti 

W 

U 

V 

Xe 

Yb 

Y 

Zn 

Zr 

-iv 

0.0055 

0.045 

0.0085 

0.0055 

0 

0.010 

0.015 

1.5 

0.0020 

* Assumption for noble gases. 

** EMSI Estimate 

Source: CF . Baes III, R.D. Sharp, A.L. Sjoreen, R.W. Shor, "A 

Review and Analysis of Parameters for Assessing 

Transport of Environmentally Released Radionuclides 

Through Agriculture," ORNL-5786, September, 1984. 

C-13 
C2.3 The Irrigation Model 

In addition to the contamination of vegetable crops through 

airborne deposition of radionuclides, crops can be contaminated 

through irrigation with contaminated water. The model presented 

in Section C l can be used to calculate a release value for 

contamination through irrigation if the release fraction (R), 

developed for airborne release of radionuclide, is set equal to 

one. All other variables in the equation have the same 

definition and the equation becomes: 

Irrigation 

Release Value = ALI/[(10)*(DF)*(FC)*(CT)*(1 x IO6) ] . (10) 

(curies) 

The radionuclide that contacts the vegetable crop is 

contained in the irrigation water rather than in an airborne 

plume, and the following assumptions are made: 

o the contaminated water is pumped from a well 30 meters 

downgradient from the radionuclide release and the 

concentration in the contaminated water is the same as 

that calculated in the ground-water ingestion model 

found in Appendix B; 

o the crop is watered daily during the 60 day growing 

season, 51 days with uncontaminated water and 9 days 

with contaminated water (see Appendix B); and 

o the leafy vegetables are eaten as harvested and not 

stored. 

The Nuclear Regulatory Commission provides equation (11)6 

for calculation of radionuclide concentration in vegetation due 

to irrigation with contaminated water. 

6U.S. Nuclear Regulatory Commission, "Calculation of Annual 

Doses to Man From Routine Releases of Reaction Effluent for the 

purpose of Evaluating Compliance with 10 CFR Part 50, Appendix 

I." Regulatory Guide 1.109, October, 1977. 

C-14 

I 

1 

1 

i 

I 

i 

t 

f 

I 

i 

i 

f 

1 

i 

I 

i 

I 

i 
P.13 

C = C I 

v w 

r[l-exp(- XEte)] f.Bv[l-exp(- X._b)] 

Y vX E PX i 

exp(- x^ ) (11 ) 

where: 

Cv == concentration of radionuclide in the edible portion of 

the crop (Ci/kg); 

Cw - concentration of radionuclide in irrigation water 

(7.6 x 10~8/Rd Ci/liter, see Appendix B); 

I = average irrigation rate during the growing season (2.5 

liters per square meter-day, liter/m2-day); 

r - fraction of deposited activity retained on crops 

(0.25) ; 

XE = Xi + Xw; 

Xi - 0.693/t 1 / 2 ; 

Xw = 0.693/t w ; 

t_/2 ~ radionuclide half life; 

tw = weathering half life (14 day); 

te = time period crops are exposed to contamination during 

the growing season (9 day); 

Yv = agricultural yield (2 kg/m2); 

fj = fraction of year crops are irrigated with contaminated 

water (9/365); 

Bv = concentration factor for soil uptake; 

t^ - period of time soil is exposed to contaminated water (9 

day) ; 

P = effective surface density of soil (240 kg/m2); and 

tn = time between harvest and consumption (0 day). 

Substituting the appropriate values into the irrigation 

model (ignoring radioactive decay and setting R^ equal to one), 

C-15 
P.14 

and dividing by the source term, 1 curie, to yield a dilution 

factor (DF) gives: 

DF = [1.7 X IO"7 + (1.9 X 10~i:L)*(Bv) ]/kg. (12) 

The second term in equation (12) is approximately one tenthousandth (1/10,000) of the first term and can be ignored on 

substitution into equation (10) to yield equation (13). 

Irrigation 

Release Value = ALI/[(0.3)*(CT)] (13) 

(curies) 

Under the same conditions, the drinking water release value 

obtained in Appendix B is: 

DW Release Value = ALI/[(1.5)*(CT)]. (14) 

Equation (14) will always yield a release value about 5 

times smaller than that given by equation (13). For this reason, 

it is not necessary to further consider the irrigation route for 

calculation of release values. 

C 3 INGESTION OF CONTAMINATED MEAT OR MILK 

Radionuclides when released to air can contaminate animal 

forage or, if released to water, can contaminate animal drinking 

water. In either case, radionuclides can be consumed by animals. 

After consumption by domestic animals such as milk producing cows 

or beef cattle, radionuclides can be found in the milk and meat 

and provide a route for the exposure of man. The ingestion model 

found in Section C l [equation (1)] can be used to calculate a 

release value for the meat or milk route after an airborne 

radionuclide release if the appropriate dilution factor (DF) can 

be derived. Similarly, equation (1) in section B.l can be used 

C-16 
P.15 

to calculate a release value for the meat or milk route after a 

release to drinking water. 

The Nuclear Regulatory Commission provides equation (15) for 

calculating the concentration of radionuclide in meat or milk.7 

This equation contains compartments for calculating the 

concentration in forage and the concentration in water and can be 

split to provide two equations, (16) and (17), separating 

airborne from waterborne releases. 

ciA = FiA(ciFQF + ciAwQAw) (15) 

ciA (airborne) = FiACiFQF (16) 

Ci A (waterborne) = Fi A CiAw QA w (17) 

where: 

CiA = concentration of radionuclide in animal product 

(Ci/liter for milk or Ci/kg for meat); 

FiA = transfer coefficient of radionuclide, the fraction 

of the daily intake that is transferred to milk 

(day/liter) or meat (day/kg) - this value is element 

dependent; 

CiE = concentration of radionuclide in forage (Ci/kg); 

Qp = feed consumed daily by animal (kg/day); 

ciAw ~ concentration of radionuclide in water (Ci/liter); 

and 

QAW

 = water consumed daily by animal (liter/day). 

Equations (15), (16) and (17) can be divided by the source term, 

1 curie, to produce a dilution factor (DF) in liters"1 or kg"1. 

A value for CiF can be found through application of equation (2) 

7U.S. Nuclear Regulatory Commission, "Calculation of Annual 

Doses to Man From Routine Releases of Reactor Effluents for the 

Purpose of Evaluating Compliance With 10 CFR Part 50, Appendix 

I." Regulatory Guide 1.109, October, 1977. 

C-17 
P.16 

in this Appendix and a value for CiAw can be found through 

application of equation (7) in Appendix B. 

These equations are valid for all radionuclides except 

tritium and carbon-14. Values for FiA, the radionuclide transfer 

coefficient, are compiled by the Nuclear Regulatory Commission in 

Regulatory Guide 1.109 (reference 7). Values for this variable 

are experimentally derived and available for only a few elements. 

For this reason, if ingestion release values for radionuclides 

were based on the meat or milk ingestion route, they could not be 

calculated for many of the 757 radionuclides without estimating 

transfer coefficients. The Agency believes that it is better to 

model ingestion of radionuclides based on consumption of leafy 

vegetables where soil to vegetable matter transfer coefficients 

(Bv) are better understood and are a minor component in the 

calculation. 

C-18 
P.17 

APPENDIX D 

MODELING OF DIRECT EXPOSURE TO RADIONUCLIDES 

In order for an exposure to an individual to occur after a 

release of radionuclide, it is not necessary for that individual to 

ingest or inhale the radionuclide. Because radionuclides produce 

radiation that can be propagated through air, it is possible for an 

exposure to occur if an individual is physically in the vicinity of 

the released radionuclide. This type of exposure is termed direct 

exposure. Because alpha particles, even very energetic alpha 

particles, have a very short range in air, it is unnecessary to 

include exposure to alpha particles in the model. Beta particles 

have a longer range in air than alpha particles, but only very high 

energy beta particles which are produced only by a very few 

radionuclides have ranges in air approaching 3 0 meters, the 

distance assumed in the model. For this reason, the Agency has 

chosen to model only direct exposure to gamma rays. 

Some uranium isotopes and a few isotopes of some transuranic 

elements decay by spontaneous fission producing neutrons which have 

ranges in air exceeding 30 meters. Because direct exposure to 

neutrons in these few cases could deliver significant radiation 

doses, the Agency also modeled this route and found that, in every 

case of spontaneous fission, release values calculated for 

inhalation were considerably lower than those calculated for direct 

exposure to gamma rays or neutrons. 

Section D.l discusses exposure to fixed point sources of 

radiation while section D.2 develops the equation used by the 

Agency for calculation of direct exposure release values for argon, 

krypton and xenon based on submersion in an airborne cloud of these 

noble gases. 

D-l 
P.18 

D.l FIXED POINT SOURCES 

The Agency believes that development of a direct exposure 

model based on exposure to a point source of solid or liquid 

radionuclide, as opposed to a line or areal source, best represents 

a sudden, episodic release of radionuclide. As is the case with 

the inhalation model and the ingestion model used to calculate 

release values for radionuclides, the exposure is assumed to occur 

at a distance of 3 0 meters from the point of release. The equation 

developed in section D.l.l is that used to calculate the release 

values based on direct exposure to such a point source of gamma 

radiation, while the equation developed in section D.l.2 was used 

by the Agency for evaluation of exposure to neutrons from 

spontaneous fission. 

D.l.l Radionuclides Which Emit Gamma Rays 

The Radiological Health Handbook1 provides the following 

equations for determining gamma ray exposure and gamma ray 

absorption from a fixed point source of radiation. 

I0 = 0.156 nx E (IO5 ua) (1) 

I = Ioe"100ua

s (2) 

R/hr = (n2 I)/S2 (3) 

where: 

I0 = unshielded exposure rate at 1 meter from a one 

curie point source (R/hr-Ci at 1 meter); 

I = attenuated radiation exposure rate (R/hr); 

n^ - gamma quanta per disintegration; 

lnThe Health Physics and Radiological Health Handbook," Nucleon 

Lectern Associates, Olney, MD, 1984, pages 41 and 45. 

D-2 
P.19 

E = energy of gamma quanta in MeV; 

ua = linear energy absorption coefficient for gamma 

rays in air (at standard temperature (23°C) and 

pressure (1 atm)) in cm"1; 

n2 = number of curies; 

S = distance in meters; and 

R/hr-Ci = exposure rate in Roentgen per hour per curie 

of release. 

When combined, these three equations become: 

R/hr-Ci = [(1.56 x 104)*(n1)*(E)*(ua)*(n2)*(e"100ua

s)]/S2 (4) 

The value for ua is found in the Radiological Health Handbook 

to be 3.7 x 10~5 cm"1 for gamma rays with an energy of 1 MeV. The 

value varies with the energy of the gamma ray involved but is 

approximately correct (±15%) for gamma rays with energies ranging 

from about 0.07 MeV to about 2 MeV. Therefore, recognizing the 

relatively small error, this single value for ua is used for all 

radionuclides for the sake of simplicity. The distance, S, used 

for other exposure routes is 30 meters and is used here. Photon 

attenuation in air between the source and receptor is represented 

by e~100ua

s. Incorporation of a term for photon attenuation in the 

equation results in a slight increase in the direct exposure 

Release Value since approximately 10 percent of the photons emitted 

from the source will be absorbed in 30 meters of air between the 

source and the receptor. A 24 hour exposure duration (T) was 

chosen because RQs are applicable for releases that occur over a 

maximum of 24 hours. Although it is recognized that it is unlikely 

that an individual actually would remain 3 0 meters away for a full 

24 hours, EPA could not conclude that it is impossible and, 

therefore, used a 24-hour exposure period to assure timely 

reporting in such an event. A shorter time period might raise the 

D-3 
P.20 

release value to such an extent that notification might not be 

given of a release that would be harmful if an individual were to 

be exposed for 24 hours or other extended periods close to 2 4 

hours. Multiplying by T to convert Roentgen per hour per curie to 

Roentgen per curie, the equation becomes: 

R/Ci = [(1.56 x 104)*(ni)*(E)*(ua)*(n2)*(T)*(e-u

a

s)]/S2. (5) 

Roentgen is approximately equal to rem for gamma rays: 

1 Roentgen = 95 ergs/gram of soft tissue; 

1 rad = 100 ergs/gram; and 

1 rem = 1 rad (for gamma rays). 

Therefore, 1 rem is approximately equal to 1 Roentgen for gamma 

rays. 

Substituting rem per curie of release (Dn) for Roentgen per 

curie (R/Ci) and rearranging equation (4) to solve for n2 gives: 

n2 = [(6.41 x 10"5)*(Dn)*(S2)]/[(n1)*(E)*(ua)*(T)*(e"100ua

s)]. (6) 

In this application, the value for n2 is the direct exposure 

release value, representing the number of curies in a point source 

yielding a specified dose-equivalent (Dn). 

As noted previously, the terms n± and E are the gamma ray 

fraction and the gamma ray energy, respectively. Many 

radionuclides emit more than one gamma ray per disintegration or 

they emit gamma rays of varying energies. Often each of these 

gamma rays are emitted only for a specific fraction of 

disintegration events. In order to account for this, the product 

of the energy of each gamma ray emitted (Ei) and the fraction of 

time it is emitted (ni) is summed to produce a value, E^, which 

reflects the total gamma ray energy produced by each radionuclide. 

The method used for this calculation is shown in equation (7). 

D-4 
P.21 

E1 = __ [(ni)*(Ei)] (7) 

i 

Some radionuclides emit positively charged electrons 

(positrons) which, when they strike negatively charged electrons, 

annihilate one another and produce two gamma rays with an energy of 

0.511 MeV each. Both annihilation gamma rays are considered in the 

calculations for those radionuclides which decay by positron 

emission. Substituting E^ for the product of n^ and E and using 

"Direct Exposure (DE) Release Value (RV)" for n2 yields: 

DE RV = [(6.41 X 10"5)*(Dn)*(S2)]/[(E1)*(Ua)*(T)*(e"100ua

S)] (8) 

Equation (8) can be used for the calculation of direct 

exposure release values when radioactive decay is not considered. 

In order to account for radioactive decay during the period of 

exposure2, this period [T in equation (8)], must be modified to 

reflect decreasing exposure at times that are successively more 

distant from the time that the radionuclide was released (an 

instantaneous release is assumed). The equation used for this 

purpose is shown below: 

T = r24i*n-expf- xtn . (9) 

X 

2Radioactive decay occurring during the period of release is 

ignored because this period could be as short as a few seconds or 

as long as one day and is undefined. Similarly, because it is 

impossible to define the time necessary for an individual to come 

into contact with the released radioactive material, the Agency 

conservatively assumed that no decay occurs over this "transport 

time". 

D-5 
P.22 

where: 

t = period of exposure in days.(1 day); 

X = radioactive decay constant (0.693/ti/2)-

ti/2 = radioactive half-life in days; and 

24 conversion factor between days and hours. 

Combining equation (8) with equation (9) yields equation (10). 

DE RV = (6.41 X 10"5)*(Dn)*(S2) (10) 

[E1]*[ua]*[exp-(100uaS)]*[24]*{[l-exp(- Xt)]/x } 

Substituting values in for Dn (0.5 rem), S (30 meters), t (1 

day), ua (3.7 x 10~5 centimeters), and X (0.693/t1/2)'

 th e equation 

reduces to: 

DE RV = 25.1 . (11) 

[E1]*[t1/2-t1/2 exp(-0.693/t1/2)] 

This equation is identical to that shown in the body of this 

report and, except for those cases calculated on the basis of 

submersion in a cloud of radioactive noble gas, was used to 

calculate the direct exposure release values shown in Appendix E. 

D.l.2 Radionuclides Which Decay by Spontaneous Fission and Emit 

Neutrons 

Included in the ICRP Publication 30 list of 757 radionuclides 

are 24 radionuclides which decay, at least part of the time, by 

spontaneous fission. These radionuclides are all either uranium 

D-6 
P.23 

isotopes or isotopes of transuranic elements3. The usual mode of 

decay for these isotopes is through the emission of alpha 

particles. Though alpha particles are not penetrating, they have a 

high quality factor4 and when radionuclides emitting alpha 

particles are ingested or inhaled and deposited in tissues, the 

damage done can be enormous. It is not surprising, then, that for 

these alpha emitting uranium isotopes and transuranics, the 

exposure pathway among the four evaluated (inhalation, ingestion of 

contaminated drinking water, ingestion of contaminated foodstuffs, 

and direct exposure) that gives the lowest calculated release 

value is inhalation. Exhibit D-l presents a list of radionuclides 

which decay by spontaneous fission and appear in the ICRP 

Publication 30 list. Exhibit D-l also provides the fraction of 

decays that occur by spontaneous fission, the inhalation release 

value and the calculated neutron exposure release value for each 

radionuclide. The method used by the Agency for determining a 

release value based on exposure to neutrons for isotopes which 

undergo spontaneous fission is described below. 

Equation (12) is commonly used for calculation of the neutron 

dose rate from an isotropic point source5. 

I » Q/[(4)*(pi)*(r2)*(8000)] (12) 

3Transuranic elements are those with higher atomic numbers than 

uranium and appear beyond uranium in the periodic chart of the 

elements. 

4The quality factor is a measure of the relative amount of damage 

done to tissues by different types of radiation. Alpha particles 

have been assigned a quality factor of 20 as compared to 10 for 

neutrons and are believed to be twice as damaging to tissues than 

neutrons. 

5"The Health Physics and Radiological Health Handbook," Nucleon 

Lectern Associates, page 38, 1984. 

D-7 
P.24 

EXHIBIT E -1 

RADIONUCLIDES INCLUDED IN ICRP PUBLICATION 

WHICH DECAY BY SPONTANEOUS FISSION 

Radionuclide 

Uranium-232 

Uranium-235 

Uranium-23 6 

Uranium-238 

Plutonium-23 6 

Plutonium-238 

Plutonium-239 

Plutonium-240 

Plutonium-244 

Curium-238 

Curium-242 

Curium-244 

Curium-246 

Curium-248 

Berkelium-249 

Californium-246 

Californium-248 

Californium-249 

Californium-250 

Californium-252 

Californium-254 

Spontaneous 

Fission 

Fraction* 

(SFF) 

9 X 

4.2 

10 

X 

-13 

IO"10 

<3 X IO"1 

5.4 

8.1 

1.8 

4.4 

4.9 

1.2 

<1.5 

6.8 

1.3 

2.6 

8.3 

4.7 

>0.( 

2.9 

5.2 

7.7 

3.1 

9.9 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

IO"7 

lo-io 

IO"9 

IO"12 

IO"8 

IO"3 

IO"4 

10~8 

IO"6 

IO"4 

IO"2 

lo-io 

301 

X 

X 

X 

X 

X 

IO"5 

IO"9 

IO"4 

1Q~2 

IO"1 

D-8 

Inhalation 

Release Value 

(Ci) 

0.01 

0.1 

0.1 

0.1 

0.1 

0.01 

0.01 

0.01 

0.01 

1000 

1 

0.01 

0.01 

0.001 

1 

10 

0.1 

0.01 

0.01 

0.1 

0.1 

m 

30 

Neutron Exposure ^ 

Release Value** • 

(Ci) • 

2.8 X 101 1 

5.9 X IO8 || 

>0.83 • 

4.6 x io5 m 

3.1 X IO8 P 

1.4 X IO8 ^ 

5.7 X IO10 | 

5.1 X IO6 

200 • 

>1700 

3.7 x IO6 • 

1.8 X IO5 W 

960 £ 

1 

5.3 X IO8 ^ 

<250 1 

8600 

4.8 X IO7 • 

320 

8.0 g 

0.25 • 
P.25 

EXHIBIT D-l - (Continued) 

RADIONUCLIDES INCLUDED IN ICRP PUBLICATION 30 

WHICH DECAY BY SPONTANEOUS FISSION 

Radionuclide 

Einsteinium-253 

Einsteinium-254m 

Fermium-254 

Spontaneous 

Fission 

Fraction* 

(SFF) 

8.7 x IO"8 

<0.001 

5.9 X IO"4 

Inhalation 

Release Value 

(Ci) 

10 

1 

100 

Neutron Exposure 

Release Value** 

(Ci) 

2.9 X IO6 

>250 

420 

** 

"Handbook of Chemistry and Physics," 63rd Edition, CRC Press, 1982 

Kocher, David C "Radioactive Decay Data Tables," Technical 

Information Center, U.S. Department of Energy, 1981. 

The phenomenon of "inscattering" might reduce these values by as 

much as 30 percent. The conclusions, however, remain unchanged. 

D-9 
P.26 

where: 

I = dose rate in rems/hour (for purposes of calculating RQs, 

a dose-equivalent of 0.5 rem and an exposure period of 24 

hours is assumed leading to an allowable average dose 

rate per hour of 0.5/24); 

Q = number of neutrons emitted per second from a point 

source; 

pi = approximately 3.14159; and 

r - distance from source to receptor in centimeters (30 

meters or 3 000 centimeters for consistency with other 

models). 

Rearranging equation (12) to solve for Q gives: 

Q = (I)*(4)*(pi)*(r2)*(8000). (13) 

Substituting in values for I, pi, and r yields: 

Q = 1.88 x 1010 neutrons/second. 

On the average, each fission yields two neutrons, therefore the 

total number of fissions per second (F) is: 

F = 9.4 x IO9 fissions/sec. (14) 

One curie is equivalent to 3.7 x 1010 disintegrations per second 

but only a fraction of the total disintegrations, the spontaneous 

fission fraction (SFF) shown in Exhibit D-l, occur by spontaneous 

fission. Division of equation (14) by the number of 

disintegrations per second equal to one curie and the spontaneous 

fission fraction for each radionuclide gives equation (15) which 

provides a release value based on direct exposure to neutrons. 

D-10 
P.27 

Neutron 

Exposure = 0.25/SFF. (15) 

Release Value 

(Ci) 

In this calculation, radioactive decay over the period of 

exposure is ignored. Inclusion of this factor would, for 

relatively short-lived radionuclides, increase the release values 

calculated on the basis of exposure to neutrons. Without 

consideration of this factor, release values calculated in this way 

are the lowest they could be but are still uniformly higher than 

release values calculated on the basis of inhalation as shown in 

the final two columns of Exhibit D-l. For this reason, the Agency 

chose to calculate direct exposure release values for all 

radionuclides on the basis of gamma ray exposure as described in 

section D.l.l, or if the radionuclides exist as a noble gas, on the 

basis of submersion in an airborne cloud as described in section 

D.2. 

D.2 SUBMERSION IN A CLOUD OF NOBLE GAS.6 

The noble gases argon, krypton, and xenon are very resistant 

to combination with other elements to form solid or liquid 

derivatives. The radioactive forms of these elements are not 

6The noble gases helium and neon do not form isotopes with halflives longer than a few seconds. None of these isotopes are listed 

in ICRP Publication 3 0 and no release values or proposed RQs have 

been calculated for them. The noble gas radon has two isotopes 

(radon-220 and radon-222) listed in ICRP Publication 30 with 

inhalation ALIs calculated with and without daughters present. Due 

to the fact that Radon-220 and Radon-222 emit alpha particles and 

some of the daughters produced by their decay emit alpha particles, 

inhalation becomes the critical exposure pathway, and submersion in 

an airborne cloud is not addressed by the ICRP for either isotope. 

The lowest of the ALIs in each case was used in the usual manner to 

calculate inhalation release values and, since submersion in an 

airborne cloud is not addressed by the ICRP for either radon 

isotope, direct exposure release values were calculated by use of 

equation (11). 

D-ll 
P.28 

likely to be found in compounds or in solid or liquid ingestible 

form. In addition, these gases have very low solubility in blood 

and are easily displaced from blood by the more common gases found 

in air such as oxygen and nitrogen. For these reasons, neither 

ingestion nor inhalation comprise a route of significant exposure 

for argon, krypton or xenon and ALIs for isotopes of these elements 

are not found in ICRP Publication 30. The one route of potential 

exposure considered significant for radioactive forms of these 

elements is through direct exposure from submersion in an airborne 

cloud (known as "cloudshine"). The equation used for calculation 

of the Direct Exposure (DE) Release Value (RV) based on submersion 

in such an airborne cloud is shown below7: 

DE RV = [(83)*(DAC)*(T)]/[(10)*(X/Q)*(1 X IO6)]. (16) 

Where: 

DAC = derived air concentration (uCi/cubic centimeter) 

from ICRP Publication 30; 

T = time of exposure (1 day); 

X/Q = atmospheric relative concentration value (8.4 x 

10"13 day/cubic centimeter); 

83 conversion factor to adjust airborne concentrations 

from a 2000 hour work year (50 weeks times 4 0 hours 

per week) to a 24 hour exposure period (2 000/24); 

and 

1 x IO6 conversion factor from microcurie (uCi) to curie. 

The-DAC is the airborne concentration to which an individual 

must be exposed for one work year (2 000 hours) in order to receive 

an occupational dose-equivalent of 5 rem. The factor of 10 

converts this occupational dose-equivalent to the 0.5 rem/yr limit 

applicable to the general public. For consistency with other 

7Annals of the ICRP, Publication 30, Part 1, Vol. 2, No. 3/4, 1979, 

Pergammon Press, pages 10 and 47. 

D-12 
P.29 

exposure pathways the atmospheric relative concentration value 

(X/Q) is derived for exposure 30 meters from the release under 

stability class D conditions (see Appendix A). In order to convert 

the duration of exposure from a 2000 hour work year to 24 hours (l 

day), the DAC must be multiplied by a factor of 83 (2000 hours/24 

hours). This is the airborne concentration that will deliver a 5 

rem dose-equivalent in 24 hours. The exposure time, T (1 day), is 

included in the equation because RQs are applicable to releases 

that occur over a maximum exposure time of 24 hours. EPA 

recognizes that it is unlikely that an individual would actually be 

exposed to an airborne cloud for a full day 3 0 meters from the 

release, but can not conclude that it is impossible and, therefore, 

uses a 24-hour exposure period in the model. Additionally, because 

the factor 83 is, as described above, derived by division of the 

2000 hour work year by the exposure time, in this case 24 hours, 

any change in exposure time, T, will be exactly compensated by a 

change in the factor of 83. For example, if a one-half day 

exposure time were chosen, T in equation (16) would become one 

half, while the numerical factor 83 would become 166 (2000/12). 

Substitution of time (T)8 and the atmospheric relative 

concentration value (X/Q) into equation (16) leads to equation (17) 

which was used for calculation of the direct exposure release 

values for isotopes of the noble gases, where appropriate. 

DE Release Value = (DAC)/(1.0 X IO"7). (17) 

8This pathway assumes an exposure to an airborne plume of 

radionuclide. Because it is not possible to establish exact bounds 

on the range of release and exposure periods, the Agency assumes 

conservatively that no decay occurs over these periods and the time 

period (T) is not adjusted for decay in this scenario. 

D-13 
P.30 

Atom. 

Radionuclide No. 

RADIONUCLIDES 

Actinium-224 89 

Actinium-225 89 

Actinium-226 89 

Actinium-227 89 

Actinium-228 89 

Aluminum-26 13 

Americium-237 95 

Americium-238 95 

Americium-239 95 

Americium-240 95 

Americium-241 95 

Americium-242m 95 

Americium-242 95 

Americium-243 95 

Americium-244m 95 

Americium-244 95 

Americium-245 95 

Americium-246m 95 

Americium-246 95 

Antimony-115 51 

Antimony-116m 51 

Antimony-116 51 

Antimony-117 51 

Antimony-118m 51 

Ingestion 

(food) 

6.6E 4 

3.4E 1 

3.6E 2 

.:&.-.QE-2 

3.2E 4 

1.2E 1* 

6.3E 6 

2.3E 6 

4.IE 4 

4.3E 3 

3.0E-1 

3.0E-1 

3.IE 4 

3.0E-1 

1.3E 7 

2.9E 4 

1.4E 6 

LIE 7 

4.4E 6 

1.4E 6 

1.9E 5 

2.8E 6 

2.4E 5 

9.6E 3 

APPENDIX E 

Release Values (Ci) 

Ingestion Inha-

(water) lation 

Direct 

Exposure 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

2.9E 1 // 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

1.6E 2* 

1.6E 0* 

1.6E 1* 

2.1E-3* 

4.7E 1* 

3.IE 1 

1.6E 6 

1.6E 4 

5.2E 4 

1.6E 4 

2.6E-2* 

2.6E-2* 

4.IE 2* 

2.6E-2* 

2.IE 4* 

1.0E 3 

4.IE 5 

1.0E 6 

5.2E 5 

1.0E 5 

3.6E 4 

1.6E 5 

1.0E 5 

1.0E 4 

1.7E 3 

1.3E 3 

3.4E 2 

5.4E 5 

1.4E 2 

2.0E 1 

2.IE 3* 

5.3E 2* 

8.0E 2* 

4.5E 1* 

3.2E 5 

7.9E 2 

9.5E 1* 

1.7E 4* 

1.7E 3* 

1.5E 3* 

2.2E 3* 

2.IE 2* 

1.3E 3* 

1.5E 3* 

4.9E 1* 

Final 

RQ (Ci) 

1& 

100 

1 

10 

0.001 

10 

10 

1000 

100 

100 

10 

0.01 

0.01 

100 

0.01 

1000 

10 

1000 

1000 

1000 

1000 

100 

1000 

1000 

10 

E-l 
P.31 

Radionuclide 

Atom. 

No. 

APPENDIX E (Continued) 

Release Values (Ci) 

Ingestion Ingestion Inha-

(food) (water) lation 

Direct 

Exposure 

Final 

RQ (Ci) 

Antimony-119 

Antimony-120 

(16 min) 

Antimony-120 

(5.76 day) 

Antimony-122 

Antimony-124m 

Antimony-124 

Antimony-125 

Antimony-126m 

Antimony-126 

Antimony-127 

Antimony-128 

(10.4 min) 

Antimony-128 

(9.01 hr) 

Antimony-129 

Antimony-130 

Antimony-131 

Argon-39 

Argon-41 

Arsenic-69 

Arsenic-70 

Arsenic-71 

Arsenic-72 

Arsenic-73 

51 

51 

51 

2.9E 3* 

3.6E 6 

8.7E 1 

v.lg. 

v.lg. 

v.lg. 

1.6E 4 

2.IE 5 

5.2E 2 

L IE 5* 

1.6E 1* 

1000 

1000 

10 

51 

51 

51 

51 

51 

51 

51 

51 

51 

51 

51 

51 

18 

18 

33 

33 

33 

33 

33 

1.2E 

5.6E 

1.8E 

6.0E 

1.5E 

3.0E 

9.IE 

4.5E 

1.1E 

6.5E 

3.0E 

2.5E 

na 

na 

LIE 

1.1E 

7.3E 

3.5E 

2.7E 

2 

6 

1* 

1* 

6 

1 

1 

6 

3 

3 

5 

5 

6 

5 

2 

2 

2* 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

na 

na 

> E 9 

> E 9 

3.9E 3 

1.8E 4 

6.4E 2 

5.2E 

3.IE 

1.0E 

2.6E 

1.0E 

2.6E 

4.7E 

2.IE 

1.6E 

4.7E 

3.IE 

1.0E 

na 

na 

5.2E 

2.6E 

2.6E 

5.2E 

1.0E 

2 

5* 

2 

2 

5 

2 

2 

5 

3 

3 

4 

4 

4* 

4 

3 

2 

3 

_ . 

9.3E 

--

2.0E 

8.9E 

1.2E 

1.4E 

6.6E 

1.9E 

2.8E 

LIE 

3.4E 

1.2E 

2.0E 

3.0E 

1.0E 

2.9E 

1.9E 

5.6E 

1* 

1 

1 

3* 

1* 

1* 

3* 

1* 

2* 

2* 

3* 

3*+ 

1*+ 

5 

2* 

2* 

1* 

10 

1000 

10 

10 

1000 

10 

10 

1000 

10 

100 

100 

1000 

1000 

10 

1000 

100 

100 

10 

100 

E-2 
APPENDIX E (Continued) 

Radionuclide 

Arsenic-74 

Arsenic-76 

Arsenic-77 

Arsenic-78 

Astatine-207 

Astatine-211 

Barium-126 

Barium-128 

Barium-131m 

Barium-131 

Barium-133m 

Barium-133 

Barium-135m 

Barium-139 

Barium-140 

Barium-141 

Barium-142 

Berkelium-245 

Berkelium-246 

Berkelium-247 

Berkelium-249 

Berkelium-250 

Beryllium-7 

Beryllium-10 

Atom. 

No. 

33 

33 

33 

33 — 

85 

85 

56 

56 

56 

56 

56 

56 

56 

56 

56 

56 

56 

97 

97 

97 

97 

97 

4 

4 

Ingestion 

(food) 

5.IE 1* 

3.9E 2 

1.1E 3* 

5.0E 4 

3.IE 5 

1.3E 3 

3.5E 4 

9.5E 1* 

1.6E 7 

1.8E 2 

5.4E 2* 

5.9E 1* 

LIE 3* 

6.8E 4 

3.0E 1* 

6.2E 5 

2.7E 6 

2.2E 3 

7.5E 3 

3.0E-1 

1.5E 1 

3.0E 4 

1.5E 3 

3.0E 1 

Release Values 

Ingestion 

(water) 

L IE 2 

1.9E 4 

1.5E 4 

> E 9 

> E 9 // 

1.6E 8 // 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

(Ci) — 

Inhalation 

4.IE 2 

5.2E 2 

2.6E 3 

1.0E 4 

1.0E 4 

2.6E 2* 

1.0E 4 

1.0E 3 

5.2E 5 

4.IE 3 

4.7E 3 

3.6E 2 

5.2E 3 

1.6E 4 

5.2E 2 

3.6E 4 

5.2E 4 

5.2E 3 

1.6E 4 

2.6E-2* 

1.0E 0* 

2.IE 2* 

1.0E 4 

5.2E 0* 

Direct 

Exposure 

8.IE 

1.3E 

6.IE 

3.9E 

3.7E 

5.3E 

1.0E 

LIE 

4.IE 

9.3E 

9.5E 

1.0E 

1.1E 

9.9E 

2.IE 

3.6E 

3.4E 

4.6E 

6.0E 

3.2E 

--

2.IE 

7.4E 

--

1 

2* 

3 

2* 

2* 

4 

3* 

3 

4* 

1* 

2 

2 

3 

3* 

2 

3* 

3* 

2* 

1* 

2 

2 

2* 

Final 

RQ (Ci) 

10 

100 

1000 

100 

100 

100 

1000 

10 

1000 

10 

100 

10 

1000 

1000 

10 

1000 

1000 

100 

10 

0.01 

1 

100 

100 

1 

E-3 
P.33 

Radionuclide 

Atom. 

No. 

APPENDIX E (Continued) 

Release Values (Ci) 

Ingestion Ingestion Inha-

(food) (water) lation 

Direct 

Exposure 

Final 

RQ (Ci) 

Bismuth-200 

Bismuth-201 

Bismuth-202 

Bismuth-203 

Bismuth-205 

Bismuth-206 

Bismuth-207 

Bismuth-210m 

Bismuth-210 

Bismuth-212 

Bismuth-213 

Bismuth-214 

Bromine-74m 

Bromine-74 

Bromine-75 

Bromine-76 

Bromine-77 

Bromine-80m 

Bromine-80 

Bromine-82 

Bromine-83 

Bromine-84 

Cadmium-104 

Cadmium-107 

83 

83 

83 

8 3 — 

83 

83 

83 

83 

83 

83 

83 

83 

35 

35 

35 

35 

35 

35 

35 

35 

35 

35 

48 

48 

4.8E 5 

5.3E 4 

5.5E 4 

1-.-7-B- 3 

5.4E 1 

5.5E 1 

3.0E 1 

1.2E 0 

8.6E 1 

4.7E 4 

8.8E 4 

5.7E 5 

1.3E 5 

4.3E 5 

1.6E 5 

2.3E 3 

3.7E 3 

4.IE 4 

1.5E 6 

8.5E 2 

1.9E 5 

3.4E 5 

1.9E 5 

2.9E 4 

v.lg. 

v.lg. 

v.lg. 

v. lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

> E 9 // 

> E 9 // 

> E 9 // 

1.3E 6 // 

2.4E 4 if 

> E 9 // 

> E 9 // 

1.6E 4 // 

> E 9 // 

> E 9 // 

v.lg. 

v.lg. 

4. IE 4 

1.6E 4 

2.IE 4 

3.IE 3 

5.2E 2 

4.7E 2 

2.IE 2 

3.6E-1* 

1.6E 1* 

1.0E 2* 

1.6E 2* 

4.IE 2* 

2.0E 4 

3.6E 4 

2.6E 4 

2.0E 3 

1.0E 4 

5.0E 3* 

1.0E 5 

2.0E 3 

3.IE 4* 

3.IE 4 

3.6E 4 

2.6E 4 

4.7E 2* 

4.7E 2* 

1.0E 3* 

4-.2E 1* 

4.4E 1* 

1.2E 1* 

2.5E 1* 

1.5E 2 

1.3E 8 

5.8E 3 

1.4E 3 

3.2E 2* 

9.7E 2* 

3.3E 2* 

2.8E 1* 

1.5E 2* 

4.0E 4* 

1.7E 1* 

3.5E 4 

6.9E 2* 

2.7E 3* 

1.6E 4* 

100 

100 

1000 

10 

10 

10 

10 

0.1 

10 

100 

100 

100 

100 

100 

100 

10 

100 

1000 

1000 

10 

1000 

100 

1000 

1000 

E-4 
APPENDIX E (Continued) 

P.34 

Radionuclide 

Cadmium-109 

Cadmium-113m 

Cadmium-113 

Cadmium-115m 

Cadmium-115 

Cadmium-117m 

Cadmium-117 

Calcium-41 

Calcium-45 

Calcium-47 

Californium-244 

Californium-246 

Californium-248 

Californium-249 

Californium-250 

Californium-251 

Californium-252 

Californium-253 

Californium-254 

Carbon-11 

Carbon-14 

Cerium-134 

Cerium-135 

Cerium-137m 

Atom. 

No. 

48 

48 

48 

48 

48 

48 

48 

20 

20 

20 

98 

98 

98 

98 

98 

98 

98 

98 

98 

6 

6 

58 

58 

58 

Ingestion 

(food) 

9.0E 0* 

5.9E-1* 

5.8E-1* 

1.1E 1* 

1.8E 2 

1.4E 4 

1.9E 4 

8.0E 1* 

5.7E 1* 

8.2E 1 

8.8E 6 

1.2E 3 

6.2E 0 

3.0E-1 

9.0E-1 

3.0E-1 

1.8E 0 

3.0E 2 

LIE 0 

--

--

7.7E 1* 

1.1E 3 

6.IE 2* 

Release Values 

Ingestion 

(water) 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

> E 9 

2.0E 3 

1.5E 0 

7.3E-2 

2.2E-1 

7.3E-2 

4.4E-1 

6.6E 1 

2.5E-1 

> E 9 

1.5E 2 

v.lg. 

v.lg. 

v.lg. 

// 

// 

// 

// 

// 

it 

it 

it 

it 

(Ci) — 

Inhalation 

2.IE 1 

1.0E 0 

1.0E 0 

2.6E 1 

5.2E 2 

5.2E 3 

5.2E 3 

2.IE 3 

4.IE 2 

4.7E 2 

3.IE 3* 

4.7E 1* 

4.7E-1* 

2.6E-2* 

5.2E-2* 

2.6E-2* 

1.6E-1* 

1.0E 1* 

1.0E-1* 

4.IE 3 

2.IE 1* 

3.6E 2 

2.IE 3 

2.IE 3 

Direct 

Exposure 

1.1E 4 

6.9E 5 

--

. LIE 3 

1.1E 2* 

7.0E 1* 

2.8E 2* 

--

--

3.5E 1* 

--

3.4E 6 

--

1.2E 2 

— 

— 

3.6E 6 

--

— 

1.8E 3* 

--

1.3E 3 

7.9E 1* 

1.4E 3 

Final 

RQ (Ci) 

1 

0.1 

0.1 

,.- 10 

100 

10 

100 

10 

10 

10 

1000 

10 

0.1 

0.01 

0.01 

0.01 

0.1 

10 

0.1 

1000 

10 

10 

10 

100 

E-5 
APPENDIX E (Continued) 

P.35 

Radionuclide 

Cerium-137 

Cerium-139 

Cerium-141 

Cerium-143 

Cerium-144 

Cesium-125 

Cesium-127 

Cesium-129 

Cesium-130 

Cesium-131 

Cesium-132 

Cesium-134m 

Cesium-134 

Cesium-135m 

Cesium-135 

Cesium-136 

Cesium-137 

Cesium-138 

Chlorine-36 

Chlorine-38 

Chlorine-39 

Chromium-48 

Chromium-49 

Chromium-51 

Atom. 

No. 

58 

58 

58 

5 8 •••••• 

58 

55 

55 

55 

55 

55 

55 

55 

55 

55 

55 

55 

55 

55. 

17 

17 

17 

24 

24 

24 

Ingest ion 

(food) 

5.4E 

1.6E 

8.2E 

3;:2E 

6.2E 

6.3E 

9.3E 

6.4E 

1.2E 

1.4E 

2.7E 

3.3E 

2.IE 

LIE 

2.IE 

2.3E 

3.0E 

3.5E 

1.7E 

9.0E 

6.0E 

2.8E 

4.IE 

1.7E 

4 

2* 

1 

2 

0 

5 

4 

3 

6 

3* 

2 

5 

0* 

6 

1* 

1 

0* 

5 

1* 

4 

4 

3 

5 

3 

Release Values 

Ingestion 

(water 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

1.5E 2 

> E 9 

> E 9 

3.IE 5 

> E 9 

3.8E 3 

) 

- • _ 

// 

// 

// 

(Ci) 

Inha 

lation 

5.2E 

3.6E 

3.IE 

V. OE 

5.2E 

5.2E 

4.7E 

1.6E 

1.0E 

1.6E 

2.IE 

5.2E 

5.2E 

1.0E 

5.2E 

3.6E 

1.0E 

3.IE 

1.0E 

2.0E 

2.6E 

3.6E 

4.IE 

1.0E 

4 

2 

2 

3 

0* 

4 

4 

4 

5 

4 

3 

4 

1 

5 

2 

2 

2 

4 

2 

4 

4 

3 

4 

4 

Direct 

Exposure 

6.9E 

2.7E 

5.2E 

• 1. 9E 

2.3E 

3.IE 

3.3E 

1.9E 

3.0E 

--

5.7E 

1.3E 

2.4E 

4.3E 

--

2.0E 

6.5E 

5.0E 

--

6.9E 

4.5E 

1.3E 

9.9E 

1.1E 

3* 

2 

1* 

2* 

3 

3* 

2* 

2* 

4* 

1* 

4* 

1 

2* 

1* 

1 

2* 

2* 

2* 

2* 

3* 

3* 

Final 

RQ (Ci) 

1000 

100 

10 

'" 100 

1 

1000 

100 

100 

1000 

1000 

10 

1000 

1 

100 

10 

10 

1 

100 

10 

100 

100 

100 

1000 

1000 

E-6 
APPENDIX E (Continued) 

P.36 

Radionuclide 

Cobalt-55 

Cobalt-56 

Cobalt-57 

Cobalt-58m 

Cobalt-58 

Cobalt-60m 

Cobalt-60 

Cobalt-61 

Cobalt-62m 

Copper-60 

Copper-61 

Copper-64 

Copper-67 

Curium-238 

Curium-240 

Curium-241 

Curium-242 

Curium-243 

Curium-244 

Curium-245 

Curium-246 

Curium-247 

Curium-248 

Curium-249 

Atom. 

No. 

27 

27 

27 

27--.. 

27 

27 

27 

27 

27 

29 

29 

29 

29 

96 

96 

96 

96 

96 

96 

96 

96 

96 

96 

96 

Ingestion 

(food) 

5.7E 3 

1.4E 2 

1.2E 3 

-•..-. 6..4E..5 

3.5E 2 

5.4E 8 

6.0E 1 

1.2E 6 

1.6E 7 

7.3E 5 

2.8E 4 

7.7E 3* 

9.0E 2 

8.0E 5 

4.3E 1 

4.IE 2 

1.9E 1 

6.0E-1 

6.0E-1 

3.0E-1 

3.0E-1 

3.0E-1 

1.2E-1 

4.5E 6 

Release Values 

Ingestion 

(water) 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

> E 9 

> E 9 

2.2E 7 

4.9E 3 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

// 

// 

// 

// 

(Ci) — 

Inhalation 

1.6E 4 

1.0E 3 

3.6E 3 

3.IE 5* 

3.6E 3 

1.6E 7 

1.6E 2 

3.IE 5 

1.0E 6 

4.7E 4 

1.6E 4 

1.0E 4 

2.6E 3 

5.2E 3* 

2.6E 0* 

1. OE 2 

1.6E 0* 

4.1E-2* 

5.2E-2* 

2.6E-2* 

2.6E-2* 

3.1E-2* 

5.2E-3* 

1.0E 5 

Direct 

Exposure 

4.9E 1* 

1.1E 1* 

3.0E 2* 

9.IE 6 

4.5E 1* 

3.0E 6* 

1.5E 1* 

4.0E 3* 

1.0E 3* 

9.9E 2* 

8.2E 2* 

8.IE 3 

3.7E 2* 

--

--

9.6E 1* 

1.0E 7 

5.0E 2 

1.4E 7 

1.7E 3 

--

1.2E 2 

--

3.IE 4* 

Fina 

RQ (C 

10 

10 

100 

1000 

10 

1000 

10 

1000 

1000 

100 

100 

1000 

100 

1000 

1 

10 

1 

0. 

0. 

0. 

0. 

0. 

0. 

1000 

1 

i ) 

- • -

01 

0 1 I 

01 

01 

01 

001 

E-7 
P.37 

Radionuclide 

Atom. 

No. 

APPENDIX E (Continued) 

Release Values (Ci) 

Ingestion Ingestion Inha-

(food) (water) lation 

Direct 

Exposure 

Final 

RQ (Ci) 

Dysprosium-155 66 8.8E 3 

Dysprosium-157 66 2.4E 4 

Dysprosium-159 66 3.2E 2 

Dysprosium-165 66 - ••• • -4. IE'4 

Dysprosium-166 66 8.7E 1* 

Einsteiniura-250 99 5.7E5 

Einsteinium-251 99 2.2E 4 

Einsteinium-253 99 9.6E 1 

Einsteinium-254m 99 8.IE 1 

Einsteinium-254 99 6.2E 0 

Erbium-161 68 5.9E 4 

Erbium-165 68 5.7E 4* 

Erbium-169 68 2.IE 2* 

Erbium-171 68 5.2E 3 

Erbium-172 68 2.2E 2 

Europium-145 63 1.9E 2 

Europium-146 63 1.1E 2 

Europium-147 63 1.3E 2 

Europium-148 63 3.6E 1 

Europium-149 63 3.4E 2* 

Europium-150 63 2.3E 3 

(12.6 hr) 

Europium-150 63 2.4E 1 

(34.2 yr) 

Europium-152m 63 3.2E 3 

2. IE 8 // 

6. IE 9 // 

7.7E 2 // 

> E 9 // 

3.3E 2 // 

7.0E 9 // 

4.8E 4 // 

2. IE 1 // 

L I E 3 // 

1.5E 0 // 

> E 9 // 

9.7E 8 // 

4.7E 2 // 

3.4E 9 // 

1.8E 3 // 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

1.6E 4 

3.IE 4 

1.0E 3 

2.6E 4 

3.6E 2 

3.6E 3 

5.2E 3* 

1.0E 1* 

5.2E 0* 

5.2E-1* 

3.IE 4 

1.0E 5 

1.6E 3 

5.2E 3 

5.2E 2 

1.0E 3 

5.2E 2 

1.0E 3 

2.IE 2 

1.6E 3 

4.IE 3 

2.0E 2* 

2.8E 2* 

1.2E 2* 

1.6E 4* 

2.7E 3 

8.2E 1* 

2.2E 5 

9.7E 1 

7.7E 4 

3.3E 2* 

2.4E 7 

2.7E 2* 

8.5E 1* 

3.2E 1* 

2.0E 1* 

8.8E 1* 

1.9E 1* 

1.2E 3 

2.0E 3* 

1.0E 1* 2.8E 1 

3.IE 3 2.8E 2* 

100 

100 

100 

1000 

10 

10 

1000 

10 

1 

0.1 

100 

1000 

100 

100 

10 

10 

10 

10 

10 

100 

1000 

10 

100 

E-8 
P.38 

Radionuclide 

Atom. 

No. 

APPENDIX E (Continued) 

Release Values (Ci) 

Ingestion Ingestion Inha-

(food) (water) lation 

Direct 

Exposure 

Final 

RQ (Ci) 

Europium-152 63 2.4E 1 v.lg. 1.0E 1* 3.5E 1 

Europium-154 63 1.5E 1 v.lg. 1.0E 1* 4.2E 1 

Europium-155 63 1.2E 2 v.lg. 4.7E 1* 7.0E 2 

Europium-156 63-........ 3...3E 1 v.lg. . . ;, 2.6E 2 2.3E 1* 

Europium-157 63 1.3E 3 v.lg. 2.6E 3 4.9E 1* 

Europiura-158 63 2.2E 5 v.lg. 3.IE 4 1.0E 3* 

Fermium-252 100 2.0E 3 LI E 4 // 5.2E 1* 

Fermium-253 100 1.6E 3 7.0E 2 // 5.2E 1* 5.5E 3 

Fermium-254 100 8.9E 4 > E 9 // 5.2E 2* 

Fermium-255 100 2.5E 3 3.9E 4 // 1.0E 2* 

Fermium-257 100 1.7E 1 3.9E 0 // 1.0E 0* 8.7E 2 

Fluorine-18 9 2.6E 5 > E 9 // 3.6E 4* 

Francium-222 87 7.9E 4 v.lg. 2.6E 2* 

Francium-223 87 1.6E 4 v.lg. 4.IE 2* 5.5E 4 

Gadolinium-145 64 1.2E 6 v.lg. 1.0E 5 8.3E 2* 

Gadolinium-146 64 3.7E 1* v.lg. 5.2E 1 2.IE 2 

Gadolinium-147 64 5.6E 2 v.lg. 2.IE 3 4.3E 1* 

Gadolinium-148 64 3.0E-1 v.lg. 4.1E-3* 

Gadolinium-149 64 2. IE 2 v.lg. 1.0E 3 LIE 2* 

Gadolinium-151 64 2.0E 2* v.lg. 2.IE 2 1.4E 3 

Gadolinium-152 64 6.0E-1 v.lg. 5.2E-3* 

Gadolinium-153 64 1.6E 2 v.lg. 5.2E 1* 7.0E 2 

Gadolinium-159 64 1.6E 3 v.lg. 3.IE 3 1.4E 3* 

Gallium-65 31 1.9E 6 > E 9 // 1.0E 5 5.7E 3* 

10 

10 

10 

• 10 .-

10 

1000 

10 

10 

100 

100 

1 

1000 

100 

100 

100 

10 

10 

0.001 

100 

100 

0.001 

10 

1000 

1000 

E-9 
APPENDIX E (Continued) 

P.39 

Radionuclide 

Gallium-66 

Gallium-67 

Gallium-68 

Gallium-70 

Gallium-72 

Gallium-73 

Germanium-66 

Germanium-67 

Germanium-68 

Germanium-69 

Germanium-71 

Germanium-75 

Germanium-77 

Germanium-78 

Gold-193 

Gold-194 

Gold-195 

Gold-198m 

Gold-198 

Gold-199 

Gold-200m 

Gold-200 

Gold-201 

Hafnium-170 

Atom. 

No. 

31 

31 

31 

31 ' 

31 

31 

32 

32 

32 

32 

32 

32 

32 

32 

79 

79 

79 

79 

79 

79 

79 

79 

79 

72 

Ingestion 

(food) 

1.0E 

1.0E 

1.7E 

1.4E 

7.IE 

9.9E 

8.3E 

8.9E 

1.5E 

2.7E 

3.IE 

2.7E 

7.7E 

1.3E 

5.0E 

8.0E 

1.6E 

2.0E 

1.7E 

4.6E 

5.3E 

3.5E 

1.5E 

1.9E 

3 

3 

5 

6 

2 

3 

4 

5 

2 

3 

4 

5 

3 

5 

3 

2 

2* 

2 

2 

2* 

2 

5 

6 

3 

Release Values 

Ingestion 

(water) 

4.8E 

4.IE 

> E 

> E 

1.0E 

> E 

> E 

> E 

3.7E 

3.7E 

6.9E 

> E 

6.0E 

> E 

1.6E 

LIE 

3.8E 

1.3E 

8.8E 

1.9E 

1.2E 

> E 

> E 

LIE 

7 // 

3 // 

9 // 

9 it ' 

6 // 

9 // 

9 // 

9 // 

2 // 

4 // 

4 // 

9 // 

7 // 

9 // 

6 // 

4 // 

2 // 

3 // 

2 // 

3 // 

5 // 

9 // 

9 // 

6 // 

(Ci) — 

Inhalation 

1.6E 

5.2E 

2.IE 

1.0E 

1.6E 

1.0E 

1.0E 

4.7E 

5.2E 

4.IE 

2.IE 

4.IE 

3.IE 

1.0E 

1.0E 

2.6E 

2.IE 

5.2E 

1.0E 

2.IE 

1.0E 

3.IE 

1.0E 

2.6E 

3 

3 

4 

5* 

3 

4 

4 

4 

1* 

3 

4* 

4 

3 

4 

4 

3 

2 

2 

3 

3 

3 

4 

5 

3 

Direct 

Exposure 

5.5E 1* 

2.4E 2* 

1.7E 4* 

3.3E 5 

3.6E 1* 

7.2E 2* 

8.4E 2* 

5.4E 3* 

— 

5.IE 1* 

--

1.5E 4* 

9.6E 1* 

1.5E 3* 

8.6E 2* 

5.8E 1* 

--

8.8E 1* 

1.0E 2* 

5.3E 2 

2.8E 1* 

3.IE 3* 

4.2E 4* 

1.4E 2* 

Final 

RQ (Ci) 

10 

100 

1000 

-1000 

10 

100 

100 

1000 

10 

10 

1000 

1000 

10 

1000 

100 

10 

100 

10 

100 

100 

10 

1000 

1000 

100 

E-10 
APPENDIX E (Continued) 

Radionuclide 

Hafnium-172 

Hafnium-173 

Hafnium-175 

Hafnium-177m 

Hafnium-178m 

Hafnium-179m 

Hafnium-180m 

Hafnium-181 

Hafnium-182m 

Hafnium-182 

Hafnium-183 

Hafnium-184 

Holmium-155 

Holmium-157 

Holmium-159 

Holmium-161 

Holmium-162m 

Holmium-162 

Holmium-164m 

Holmium-164 

Holmium-166m 

Holmium-166 

Holmium-167 

Hydrogen-3 

Atom. 

No. 

72 

72 

72 

72 

72 

72 

72 

72 

72 

72 

72 

72 

67 

67 

67 

67 

67 

67 

67 

67 

67 

67 

67 

1 

Ingestion 

(food) 

3.0E 

2.2E 

1.0E 

6.2E 

2.6E 

1.8E 

1.2E 

3.8E 

3.7E 

6.0E 

1.8E 

4.7E 

4.8E 

1.4E 

3.5E 

3.8E 

4.2E 

1.9E 

1.5E 

3.9E 

1.8E 

3.4E 

6.2E 

--

1 

3 

2* 

8 

6 

6 

4 

1* 

5 

0 

5 

3 

5 

7 

6 

5 

5 

7 

6 

6 

1 

2* 

4 

Release Values 

Ingestion 

(water) 

7.4E 1 // 

1.6E 5 // 

2.4E 2 // 

> E 9 // 

> E 9 // 

> E 9 // 

> E 9 // 

8.7E 1 // 

> E 9 // 

1.5E 1 // 

> E 9 // 

> E 9 // 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

5.9E 3 

(Ci) — 

Inhalation 

4.7E 0* 

5.2E 3 

4.7E 2 

3.IE 4* 

5.2E-1* 

1.6E 2* 

1.0E 4 

1.0E 2 

4.7E 4 

4.1E-1* 

2.6E 4 

3.IE 3 

1.0E 5 

5.2E 5 

5.2E 5 

2.IE 5 

1.6E 5 

1.0E 6 

1.6E 5* 

3.IE 5* 

3.6E 0* 

1.0E 3 

3.IE 4 

8.3E 2* 

Direct 

Exposure 

1.5E 

1.6E 

1.2E 

2.IE 

5.7E 

5.6E 

1.2E 

7.4E 

6.7E 

1.6E 

7.9E 

6.7E 

7.8E 

9.2E 

5.4E 

4.5E 

1.1E 

3.7E 

6.9E 

3.5E 

2.2E 

2.2E 

6.IE 

--

3 

2* 

2 

6 

5 

5 

2* 

1 

2* 

2 

2* 

2* 

3* 

3* 

3* 

4* 

3* 

4* 

6 

5 

1 

3 

2* 

Final 

RQ (Ci) 

1 

100 

100 

1000 

0.1 

100 

100 

10 

100 

0.1 

100 

100 

1000 

1000 

1000 

1000 

1000 

1000 

1000 

1000 i 

i I 

1 

100 

100 ' 

100 1 

E-l l 
APPENDIX E (Continued) 

P.41 

Radionuclide 

Indium-109 

Indium-110 

(69.1 min) 

Indium-110 

(4.9 hr) 

Indium-Ill 

Indium-112 

Indium-113m 

Indium-114m 

Indium-115m 

Indium-115 

Indium-116m 

Indium-117m 

Indium-117 

Indium-119m 

Iodine-120m 

Iodine-120 

Iodine-121 

Iodine-123 

Iodine-124 

Iodine-125 

Iodine-126 

Iodine-128 

Iodine-129 

Iodine-130 

Atom. 

No. 

49 

49 

49 

49 

49 

49 

49 

49 

49 

49 

49 

49 

49 

53 

53 

53 

53 

53 

53 

53 

53 

53 

53 

Ingestion 

(food) 

4.6E 4 

1.7E 5 

9.8E 3 

6.8E 2 

7.9E 6 

2.9E 5 

1.1E 1* 

2.IE 4 

1.2E 0 

2.IE 5 

4.9E 4 

8.0E 5 

1.3E 6 

2.IE 3 

5.6E 2 

1.1E 3 

4.5E 1* 

1.2E-1* 

2.8E-2* 

2.3E-2* 

1.8E 4 

3.0E-3* 

6.3E 0* 

Release Values 

Ingestion 

(water) 

> E 9 // 

> E 9 // 

> E 9 // 

3.2E 3 // 

> E 9 // 

> E 9 // 

2.5E 1 // 

> E 9 // 

> E 9 // 

> E 9 // 

> E 9 // 

> E 9 // 

> E 9 // 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

(Ci) — 

Inhalation 

2.IE 4 

2.IE 4 

1.0E 4 

3.IE 3 

3.IE 5 

5.2E 4 

3.IE 1 

2. IE 4 

5.2E-1* 

4.IE 4 

1.6E 4 

1.0E 5 

5.2E 4* 

2.IE 2* 

9.3E 1* 

2.IE 2* 

6.2E 1 

8.3E-1 

6.2E-1 

4.1E-1 

1.0E 3* 

9.3E-2 

7.2E 0 

Direct 

Exposure 

4.5E 2* 

6.8E 2* 

4.5E 1* 

1.1E 2* 

6.0E 4* 

1.5E 3* 

4.8E 2 

8.9E 2* 

— 

3.3E 2* 

5.2E 2* 

1.2E 3* 

9.IE 4 

2.4E 2 

4.9E 2 

1.5E 3 

4.5E 2 

5.3E 1 

--

1.0E 2 

1.7E 4 

--

3.2E 1 

Final 

RQ (Ci) 

100 

100 

10 

100 

1000 

1000 

10 

100 

0.1 

100 

100 

1000 

1000 

100 

10 

100 

10 

0.1 

0.01 

0.01 

1000 

0.001 

1 

E-12 
APPENDIX E (Continued) 

Radionuclide 

Iodine-131 

Iodine-132m 

Iodine-132 

Iodine-133 

Iodine-134 

Iodine-135 

Iridium-182 

Iridium-184 

Iridium-185 

Iridium-186 

Iridium-187 

Iridium-188 

Iridium-189 

Iridium-190m 

Iridium-190 

Iridium-192m 

Iridium-192 

Iridium-194m 

Iridium-194 

Iridium-195m 

Iridium-195 

Iron-52 

Iron-55 

Iron-59 

Atom. 

No. 

53 

53 

53 

;:-53-

53 

53 

77 

77 

77 

77 

77 

77 

77 

77 

77 

77 

77 

77 

77 

77 

77 

26 

26 

26 

Ingestion 

(food) 

4.6E-2* 

5.5E 2 

3.2E 2 

-••--9.7E-1* 

4.3E 3 

2.3E 1 

1.5E 7 

2.6E 5 

3.5E 4 

1.3E 4 

9.3E 4 

5.IE 3 

2.9E 3 

1.6E 7 

6.2E 2 

1.2E 7 

3.IE 2 

1.9E 2 

5.2E 3 

2.0E 5 

3.4E 5 

1.1E 3 

2.7E 2* 

3.0E 1* 

Release Values 

Ingestion 

(water) 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

> E 9 

> E 9 

4.9E 6 

8.IE 5 

1.4E 8 

6. IE 3 

// 

// 

// 

// 

it 

it 

6.3E 2*// 

> E 9 

1.3E 2 

> E 9 

7.3E 1 

4.6E 1 

1.0E 5 

> E 9 

> E 9 

v.lg. 

v.lg. 

v.lg. 

it 

it 

it 

it 

it 

it 

it 

it 

(Ci) — 

Inhalation 

5.2E-1 

8.3E 1* 

8.3E 1* 

3.IE 0 

5.2E 2 

2.IE 1* 

5.2E 5 

1.0E 5 

5.2E 4 

3.IE 4 

1.6E 5 

1.6E 4 

2. IE 4 

1.0E 6* 

4.7E 3 

1.0E 2* 

1.0E 3 

4.7E 2 

1.0E 4 

1.0E 5 

2.IE 5 

1.0E 3 

1.0E 3 

1.6E 2 

Direct 

Exposure 

1.0E 

2.IE 

1.5E 

5.6E 

2.9E 

6.6E 

4.8E 

1.6E 

1.3E 

5.4E 

3.7E 

2.7E 

1.8E 

--

3.4E 

6.7E 

4.8E 

1.6E 

7.IE 

5.6E 

1.5E 

5.IE 

--

3.IE 

2 

2 

3 

1 

2* 

1 

3* 

2* 

2* 

1* 

2* 

1* 

3 

1* 

8 

1* 

1* 

2* 

2* 

4* 

2* 

1 

Final 

RQ (Ci) 

0.01 

10 

10 

0 . 1 -••• 

100 

10 

1000 

100 

100 

.0 

100 

10 

100 

1000 

10 

100 

10 

10 

100 

100 

1000 

100 

100 

10 

E-13 
APPENDIX E (Continued) 

P.43 

Radionuclide 

Iron-60 

Krypton-74 

Krypton-76 

Krypton-77 

Krypton-79 

Krypton-81 

Krypton-83m 

Krypton-85m 

Krypton-85 

Krypton-87 

Krypton-88 

Lanthanum-131 

Lanthanum-132 

Lanthanum-135 

Lanthanum-137 

Lanthanum-138 

Lanthanum-140 

Lanthanum-141 

Lanthanum-142 

Lanthanum-143 

Lead-195m 

Lead-198 

Lead-199 

Lead-200 

Atom. 

No. 

26 

36 

36 

36.—. 

36 

36 

36 

36 

36 

36 

36 

57 

57 

57 

57 

57 

57 

57 

57 

57 

82 

82 

82 

82 

Ingestion 

(food) 

8.9E-1* 

na 

na 

.--' na 

na 

na 

na 

na 

na 

na 

na 

4.8E 5 

6.0E 3 

2.IE 4 

3.0E 2 

2.7E 1 

1.6E 2 

9.8E 3 

5.0E 4 

1.6E 6 

2.3E 6 

1.2E 5 

1.3E 5 

1.4E 3 

Release Values 

Ingestion 

(water) 

v.lg. 

na 

na 

na 

na 

na 

na 

na 

na 

na 

na 

> E 9 

> E 9 

3.8E 6 

7.3E 2 

6.6E 1 

2.0E 3 

> E 9 

> E 9 

> E 9 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

// 

// 

// 

// 

// 

// 

// 

// 

// 

(Ci) — 

Inhalation 

3.IE 0 

na 

na 

*. .na 

na 

na 

na 

na 

na 

na 

na 

5.2E 4 

5.2E 3 

4.7E 4 

3.IE 1* 

2.IE 0* 

5.2E 2 

4.7E 3* 

1.0E 4 

4.7E 4* 

1.0E 5 

3.IE 4 

3.6E 4 

3.IE 3 

Direct 

Exposure 

6.2E 

3.0E 

9.0E 

4.0E 

2.0E 

7.0E 

1.0E 

2.0E 

1.0E 

5.0E 

2.0E 

2.5E 

1.0E 

5.8E 

--

> E 

2.0E 

6.6E 

2.3E 

4.7E 

2.2E 

7.3E 

5.3E 

4.7E 

2 

1*+ 

1*+ 

1*+ 

2*+ 

3*+ 

5*+ 

2*+ 

3*+ 

1*+ 

1*+ 

3* 

2* 

3* 

9 

1* 

3 

2* 

4 

3* 

2* 

2* 

2* 

Final 

RQ (Ci) 

0.1 

10 

10 

10 

100 

1000 

1000 

100 

1000 

10 

10 

1000 

100 

IOOO 

10 

1 

10 

1000 

100 

1000 

1000 

100 

100 

100 

E-14 
APPENDIX E (Continued) 

P.44 

Radionuclide 

Lead-201 

Lead-202m 

Lead-202 

Lead-203 

Lead-205 

Lead-209 

Lead-210 

Lead-211 

Lead-212 

Lead-214 

Lutetium-169 

Lutetium-170 

Lutetium-171 

Lutetium-172 

Lutetium-173 

Lutetium-174m 

Lutetium-174 

Lutetium-176m 

Lutetium-176 

Lutetium-177m 

Lutetium-177 

Lutetium-178m 

Lutetium-178 

Lutetium-179 

Atom. 

No. 

82 

82 

82 

82 

82 

82 

82 

82 

82 

82 

71 

71 

71 

71 

71 

71 

71 

71 

71 

71 

71 

71 

71 

71 

Ingestion 

(food) 

7.3E 3 

2.4E 4 

3.0E 0* 

1.1E 3 

1.2E 2* 

5.9E 4 

1.8E-2* 

1.6E 5 

7.4E 1 

1.9E 5 

9.2E 2 

2.3E 2 

1.5E 2 

8.7E 1 

1.5E 2* 

6.5E 1* 

1.5E 2 

2.IE 4 

2.IE 1 

2.2E 1* 

1.7E 2* 

1.2E 6 

8.0E 5 

1.3E 4 

Release Values 

Ingestion 

(water) 

v.lg. 

v.lg. 

v.lg. 

v.lg. -

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

1.8E 4 // 

1.9E 3 // 

3.5E 2 // 

2. IE 2 // 

3.7E 2 // 

1.5E 2 // 

3.7E 2 // 

> E 9 // 

5. IE 1 // 

5.4E 1 // 

4.2E 2 // 

> E 9 // 

> E 9 // 

> E 9 // 

(Ci) — 

Inhalation 

1.0E 4 

1.6E 4 

2.6E 1 

•4.7E 3 

5.2E 2 

3.IE 4* 

1.0E-1 

3.IE 2* 

1.6E 1* 

4.IE 2* 

2.IE 3 

1.0E 3 

1.0E 3 

5.2E 2 

1.6E 2 

1.0E 2 

5.2E 1* 

1.0E 4* 

2.6E 0* 

4.IE 1 

1.0E 3 

1.0E 5 

5.2E 4 

1.0E 4 

Direct 

Exposure 

1.4E 2* 

8.7E 1* 

--

1.8E 2* 

--

--

--

1.9E 4 

6.3E 2 

6.3E 3 

7.7E 1* 

2.5E 1* 

7.0E 1* 

2.4E 1* 

6.8E 2 

4.3E 3 

4.3E 2 

2. IE 4 

> E 9 

4.IE 1 

1.3E 3 

3.6E 4* 

1.3E 4* 

5.IE 3* 

Final 

RQ (Ci) 

100 

10 

1 

-- 100 

100 

1000 

0.01 

100 

10 

100 

10 

10 

10 

10 

100 

10 

10 

1000 

1 

10 

100 

1000 

1000 

1000 

E-15 
Radionuclide 

Magnesium-28 

Manganese-51 

Manganese-52m 

Manganese-52 

Manganese-53 

Manganese-54 

Manganese-56 

Mendelevium-257 

Mendelevium-258 

Mercury-193m 

Mercury-193 

Mercury-194 

Mercury-195m 

Mercury-195 

Mercury-197m 

Mercury-197 

Mercury-199m 

Mercury-203 

Molybdenum-90 

Molybdenum-9 3m 

Molybdenum-93 

Molybdenum-99 

Molybdenum-101 

Neodymium-136 

Atom. 

N o. 

12 

25 

25 

25,-.; 

25 

25 

25 

101 

101 

80 

80 

80 

80 

80 

80 

80 

80 

80 

42 

42 

42 

42 

42 

60 

APPENDIX E (Continued) 

t>_l tr 1.. fm \ 

Ingestion 

(food) 

3.3E 2 

2.5E 5 

8.0E 5 

:y:;:yE:l 

1.5E 3* 

6.IE 1 

1.8E 4 

1.7E 5 

2.5E 1 

2.4E 3 

4.9E 4 

5.8E-1* 

5.2E 2 

9.9E 3 

1.2E 3 

1.0E 3* 

7.8E 5 

1.8E 1* 

3.4E 3 

5.6E 3 

1.2E 2 

1.7E 2* 

1.6E 6 

1.1E 5 

Ingestion 

(water) 

4.2E 4 // 

> E 9 // 

> E 9 // 

1.8E 2 // *. 

3.7E 3 // 

1.5E 2 // 

> E 9 it 

> E 9 // 

5.8E 0 // 

1.3E 7 // 

> E 9 // 

1.5E 0 // 

6.8E 3 // 

4.2E 8 // 

9.2E 4 // 

5.4E 3 // 

> E 9 // 

4.3E 1 // 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

E-16 

Inhalation 

5.2E 

2.6E 

4.7E 

4.7E 

5.2E 

4.IE 

1.0E 

5.2E 

1.6E 

4.IE 

1.6E 

1.6E 

2.IE 

1.6E 

2.6E 

4.IE 

4.IE 

4.IE 

2.6E 

5.2E 

1.0E 

5.2E 

5.2E 

2.6E 

2 

4* 

4 

2 

3 

2 

4 

2* 

0* 

3 

4 

1 

3 

4 

3 

3 . 

4 

2 

3 

3 

2* 

2 

4 

4 

Direct 

Exposure 

3.7E 1* 

1.5E 5 

1.2E 3* 

1.7E 1* 

--

4.4E 1* 

1.4E 2* 

--

--

5.4E 1* 

2.3E 2* 

--

2.5E 2* 

6.4E 2* 

1.1E 3* 

2.8E 3 

6.3E 3* 

1.6E 2 

1.5E 2* 

4.2E 1* 

--

1.7E 2 

4.5E 3* 

5.IE 3* 

Final 

RQ (Ci) 

10 

1000 

1000 

~10 

1000 

10 

100 

100 

-1 

10 

100 

0.1 

100 

100 

1000 

1000 

1000 

10 

100 

10 

100 

100 

1000 

1000 

P.45 
P.46 

Radionuclide 

Atom. 

No. 

APPENDIX E (Continued) 

Release Values (Ci) 

Ingestion Ingestion Inha-

(food) (water) lation 

Direct 

Exposure 

Final 

RQ (Ci) 

Neodymium-138 

Neodymium-139m 

Neodymium-139 

Neodymium-141 

Neodymium-147 

Neodymium-149 

Neodymium-151 

Neptunium-232 

Neptunium-233 

Neptunium-234 

Neptunium-235 

Neptunium-236 

(1.2 E 5 yr) 

Neptunium-236 

(22.5 hr) 

Neptunium-237 

Neptunium-238 

Neptunium-239 

Neptunium-240 

Nickel-56 

Nickel-57 

Nickel-59 

Nickel-63 

Nickel-65 

Nickel-66 

60 

60 

60 

60 

60 

60 

60 

93 

93 

93 

93 

93 

93 

5.2E 4 

9.5E 3 

1.7E 6 

7.7E 5 

6.4E 1* 

5.5E 4 

3.2E 6 

1.2E 7 

1.3E 8 

2.4E 3 

3.IE 3* 

1.2E-1* 

2.2E 3 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

93 

93 

93 

93 

28 

28 

28 

28 

28 

28 

2.1E-2* 

1.7E 3 

3.9E 3 

1.8E 6 

9.3E 1 

5.8E 2 

5.9E 2* 

2.7E 2* 

3.0E 4 

8.IE 1* 

v.lg 

v.lg 

v.lg 

v.lg 

v.lg 

v.lg 

v.lg 

v.lg 

v.lg 

v.lg 

2.6E 3* 

5.2E 3 

1.6E 5 

3.IE 5 

4.IE 2 

1.0E 4 

1.0E 5 

1.0E 4 

1.6E 7 

1.6E 4 

5.2E 3 

1.6E-1 

2.IE 2* 

1.5E 5 

LIE 2* 

1.3E 4* 

1.2E 4* 

3.IE 2 

7.8E 2* 

4.7E 3* 

2.5E 3* 

1.5E 5* 

3.9E 1* 

6.9E 2 

6.9E 3 

3.1E-2 

4.7E 2 

1.0E 4 

4.IE 5 

5.2E 2 

1.6E 3 

2.IE 3 

1.0E 3 

1.0E 4 

3.IE 2 

2.6E 3 

6.9E 1* 

3.9E 2* 

5.4E 2* 

2.3E 1* 

3.0E 1* 

--

— 

4.5E 2* 

__ 

1000 

100 

1000 

1000 

10 

100 

1000 

1000 

1000 

10 

1000 

0.1 

100 

0.01 

10 

100 

100 

10 

10 

100 

100 

100 

10 

E-17 
APPENDIX E (Continued) 

P.47 

Radionuclide 

Niobium-88 

Niobium-89 

(66 min) 

Niobium-89 

(122 min) 

Niobium-90 

Niobium-93m 

Niobium-94 

Niobium-95m 

Niobium-95 

Niobiura-96 

Niobium-97 

Niobium-98 

Osmium-180 

Osmium-181 

Osmium-182 

Osmium-185 

Osmium-189m 

Osmium-191m 

Osmium-191 

Osmium-193 

Osmium-194 

Palladium-100 

Palladium-101 

Palladium-103 

Atom. 

No. 

41 

41 

41 

41 

41 

41 

41 

41 

41 

41 

41 

76 

76 

76 

76 

76 

76 

76 

76 

76 

46 

46 

46 

Ingestion 

(food) 

2.0E 

8.7E 

2.4E 

6.8E 

2.7E 

2.7E 

2.8E 

8.0E 

4.3E 

1.6E 

1.2E 

2.6E 

5.5E 

9.4E 

6.7E 

1.3E 

7.5E 

LIE 

6.7E 

1.2E 

1.4E 

1.2E 

3.IE 

6 

4 

4 

2 

2 

1 

2* 

1 

2 

5 

8 

6 

4 

2 

1 

5 

3* 

2* 

2* 

1 

2* 

4 

2* 

Release Values 

Ingestion 

(water) 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

> E 9 // 

> E 9 // 

1.1E 5 // 

1.6E 2 // 

> E 9 it 

1.7E 7 // 

2.3E 2 // 

1.8E 4 // 

2.9E 1 // 

v.lg. 

v.lg. 

v.lg. 

(Ci) — 

Inhalation 

1.0E 

2.IE 

1.0E 

1.0E 

1.0E 

1.0E 

1.0E 

5.2E 

1.0E 

3.6E 

2.6E 

2. IE 

2.IE 

2.IE 

2.6E 

1.0E 

1.0E 

5.2E 

1.6E 

4.IE 

5.2E 

1.6E 

2.IE 

5 

4 

4 

3 

2* 

1* 

3 

2 

3 

4 

4* 

5* 

4 

3 

2 

5* 

4 

2 

3 

0* 

2 

4 

3 

Direct 

Exposure 

7.9E 2* 

3.0E 2* 

8.IE 2* 

1.5E 1* 

--

2.3E 1 

6.IE 2 

4.8E 1* 

2.2E 1* 

7.4E 2* 

1.2E 7 

--

4.4E 2* 

1.4E 2* 

5.5E 1* 

--

1.2E 6 

1.1E 3 

1.1E 3 

--

2.3E 2 

3.7E 2* 

4.IE 5 

Final 

RQ (Ci) 

100 

100 

100 

10 

100 

10 

100 

10 

10 

100 

1000 

1000 

100 

100 

10 

1000 

1000 

100 

100 

1 

100 

100 

100 

E-18 
APPENDIX E (Continued) 

Radionuclide 

Palladium-107 

Palladium-109 

Phosphorus-32 

Phosphorus-33 

Platinum-186 

Platinum-188 

Platinum-189 

Platinum-191 

Platinum-193m 

Platinum-193 

Platinum-195m 

Platinum-197m 

Platinum-197 

Platinum-199 

Platinum-200 

Plutonium-234 

Plutonium-235 

Plutonium-236 

Plutonium-237 

Plutonium-238 

Plutonium-239 

Plutonium-240 

Plutonium-241 

Plutonium-242 

Atom. 

No. 

46 

46 

15 

is----

78 

78 

78 

78 

78 

78 

78 

78 

78 

78 

78 

94 

94 

94 

94 

94 

94 

94 

94 

94 

Ingestion 

(food) 

8.9E 2 

1.5E 3* 

6.0E-1* 

:*:*-_4-.7E 0* 

4.8E 4 

1.3E 2* 

9.0E 3 

6.5E 2 

3.6E 2* 

1.2E 3* 

2.5E 2* 

1.2E 5 

1.6E 3* 

9.2E 5 

7.9E 2* 

9.9E 4 

2.0E 8 

6.0E 0 

3.8E 3* 

2.IE 0 

1.8E 0 

1.8E 0 

9.0E 1 

2.IE 0 

Release Values 

Ingestion 

(water) 

v.lg. 

v.lg. 

7.2E 1 // 

5. 8E 2 it - -

> E 9 it 

2.9E 2 // 

9.5E 7 it 

2.9E 3 // 

L I E 3 // 

2.9E 3 // 

8. IE 2 // 

> E 9 // 

4.2E 5 // 

> E 9 // 

2.6E 6 // 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

(Ci) — 

Inhalation 

2.IE 2* 

2.6E 3 

4.IE 0 

3. IE 1 

2.IE 4 

1.0E 3 

1.6E 4 

4.IE 3 

3.IE 3 

1.0E 4 

2.IE 3 

2.IE 4 

4.7E 3 

5.2E 4 

1.6E 3 

1.0E 3* 

1.6E 7* 

1.0E-1* 

1.6E 4 

3.1E-2* 

2.6E-2* 

2.6E-2* 

1.6E 0* 

3.1E-2* 

Direct 

Exposure 

_. _ 

1.6E 4 

--

4.0E 2* 

3.IE 2 

4.4E 2* 

2.2E 2* 

2.6E 5 

--

2.7E 3 

9.9E 3* 

7.3E 3 

6.7E 3* 

3.4E 3 

--

--

--

--

--

1.7E 6 

5.0E 6 

1.4E 8 

4.IE 6 

Final 

RQ (Ci) 

100 

1000 

0.1 

-H 

100 

100 

100 

100 

1Q0 

1000 

100 

1000 

1000 

1000 

100 

1000 

1000 

0.1 

1000 

0.01 

0.01 

0.01 

1 

0.01 

E-19 
P.49 

Radionuclide 

Atom. 

No. 

APPENDIX E (Continued) 

Release Values (Ci) 

Ingestion Ingestion Inha-

(food) (water) lation 

Direct 

Exposure 

Final 

RQ (Ci) 

Plutonium-243 94 3.9E 5 v.lg. 

Plutonium-244 94 2.IE 0 v.lg. 

Plutonium-245 94 1.9E 4 v.lg. 

Polonium-203 84 4.9E 5 v.lg. 

Polonium-205 84 1.1E 5 v.lg. 

Polonium-207 84 1.3E 4 v.lg. 

Polonium-210 84 9.7E-2* v.lg. 

Potassium-40 19 8.6E 0* v.lg. 

Potassium-42 19 3.9E 3 v.lg. 

Potassium-43 19 2.6E 3 v.lg. 

Potassium-44 19 5.0E 5 v.lg. 

Potassium-45 19 9.6E 5 v.lg. 

Praseodymium-136 59 2.2E 6 v.lg. 

Praseodymium-137 59 3.0E 5 v.lg. 

Praseodymium-138m 59 4.6E 4 v.lg. 

Praseodymium-139 59 8.7E 4 v.lg. 

Praseodymium-142m 59 3.IE 6 v.lg. 

Praseodymium-142 59 5.3E 2* v.lg. 

Praseodymium-143 59 5.2E 1* v.lg. 

Praseodymium-144 59 9.9E 5 v.lg. 

Praseodymium-145 59 4.9E 3 v.lg. 

Praseodymium-147 59 2.IE 6 v.lg. 

Promethium-141 61 1.4E 6 v.lg. 

Promethium-143 61 1.6E 2 v.lg. 

2.IE 5 

3.1E-2* 

2.IE 4 

3.IE 4 

2.IE 4 

1.6E 4 

3.1E-1 

2.IE 2 

2.6E 3 

4.7E 3 

3.6E 4 

5.2E 4 

1.0E 5 

5.2E 4 

2.IE 4 

5.2E 4 

5.2E 4* 

1.0E 3 

3.6E 2 

5.2E 4* 

4.IE 3* 

1.0E 5 

1.0E 5 

3.IE 2 

5.7E 3* 

3.IE 2* 

8.8E 2* 

2.7E 2* 

9.4E 1* 

4.5E 6 

2.4E 2 

2.3E 2* 

5.9E 1* 

6.8E 2* 

1.2E 3* 

2.3E 3* 

1.5E 4* 

1.4E 2* 

1.5E 3* 

9.3E 2 

5.0E 8 

7.4E 4 

9.2E 3 

4.6E 3* 

2.7E 3* 

1.3E 2* 

1000 

0.01 

100 

100 

100 

10 

0.01 

1 

100 

10 

100 

1000 

1000 

1000 

100 

1000 

1000 

100 

10 

1000 

1000 

1000 

1000 

100 

E-20 
P.50 

APPENDIX E (Continued) 

Radionuclide 

Promethium-144 

Promethium-145 

Promethium-146 

Promethium-147 

Promethium-148m 

Promethium-148 

Promethium-149 

Promethium-150 

Promethium-151 

Protactinium-227 

Protactinium-228 

Protactinium-230 

Protactinium-231 

Protactinium-232 

Protactinium-233 

Protactinium-234 

Radium-223 

Radium-224 

Radium-225 

Radium-226 

Radium-227 

Radium-228 

Radon-220 

Radon-222 

Atom. 

No. 

61 

61 

61 

61 : .-

61 

61 

61 

61 

61 

91 

91 

91 

91 

91 

91 

91 

88 

88 

88 

88 

88 

88 

86 

86 

Ingestion 

(food) 

3.IE 1 

3.0E 2 

6.0E 1 

_ _ 1.2E 2 

2.7E 1 

4.IE 1* 

2.IE 2* 

1.8E 4 

7.3E 2 

6.0E 5 

4.6E 3 

3.IE 2 

6.0E-2 

3.3E 3 

4.3E 2 

2.9E 4 

3.IE 0* 

LIE 1 

4.4E 0 

6.0E-1* 

2.7E 6 

6.0E-1* 

na 

na 

Release Values 

Ingestion 

(water) 

v.lg. 

v.lg. 

v.lg. 

v-lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

na 

na 

(Ci) — 

Inhalation 

5.2E 1 

1.0E 2* 

2.IE 1* 

5.2E 1* 

1.6E 2 

2.6E 2 

1.0E 3 

1.0E 4 

1.6E 3 

5.2E 2* 

5.2E 1* 

2.IE 1* 

1.0E-2* 

1.0E 2 

3.IE 3 

3.6E 4 

3.6E 0 

1.0E 1* 

3.6E 0* 

3.IE 0 

5.2E 4 

5.2E 0 

1.0E-1* 

5.2E-1* 

Direct 

Exposure 

2.4E 1* 

2.8E 4 

5.0E 1 

9.5E 6 

1.8E 1* 

6.9E 1 

3.9E 3 

1.9E 2* 

2.IE 2* 

5.IE 5 

6.9E 1 

6.4E 1 

1.8E 3 

5.IE 1* 

2.3E 2* 

7.6E 1* 

4.6E 2 

4.2E 3 

--

5.9E 3 

7.5E 3* 

--

--

1.1E 5 

Final 

RQ (Ci) 

10 

100 

10 

10 

10 

10 

100 

100 

100 

100 

10 

10 

0.01 

10 

100 

10 

1 

10 

1 

0.1 

1000 

0.1 

0.1 

0.1 

E-21 
P.51 

Radionuclide 

Atom. 

No. 

APPENDIX E (Continued) 

Release Values (Ci) 

Ingestion Ingestion Inha-

(food) (water) lation 

Direct 

Exposure 

Final 

RQ (Ci) 

Rhenium-177 

Rhenium-178 

Rhenium-181 

Rhenium-182 

(12.7 hr) 

Rhenium-182 

(64.0 hr) 

Rhenium-184m 

Rhenium-184 

Rhenium-186m 

Rhenium-186 

Rhenium-187 

Rhenium-188m 

Rhenium-188 

Rhenium-189 

Rhodium-99m 

Rhodium-99 

Rhodium-100 

Rhodium-lOlm 

Rhodium-101 

Rhodium-102m 

Rhodium-102 

Rhodium-103m 

Rhodium-105 

Rhodium-106m 

75 

75 

75 

75 

75 

75 

75 

75 

75 

75 

75 

75 

75 

45 

45 

45 

45 

45 

45 

45 

45 

45 

45 

3.5E 6 

2.9E 6 

2.4E 3 

5.2E 3 

1.7E 2 

6.IE 1* 

7.5E 1 

2.8E 1* 

2.5E 2* 

1.7E 4* 

2.3E 6 

L IE 3* 

1.2E 3 

4.IE 4 

1.1E 2 

9.7E 2 

7.IE 2 

6.0E 1* 

3.IE 1* 

1.8E 1 

4.IE 6 

1.2E 3 

3.5E 4 

> E 9 // 

> E 9 // 

4.0E 5 // 

1.6E 7 // 

9.0E 2 // 

1.5E 2 // 

1.8E 2 // 

7.3E 1 // 

9. IE 2 // 

4.4E 4 // 

> E 9 // 

4.6E 5 // 

8.8E 4 // 

> E 9 // 

2.3E 2 // 

1.3E 5 // 

2.2E 3 // 

1.5E 2 // 

7.6E 1 // 

4.4E 1 // 

> E 9 // 

2. IE 4 // 

> E 9 // 

1.6E 5 

1.6E 5 

4.7E 3 

5.2E 3 

1.0E 3 

2.IE 2 

5.2E 2 

1.0E 2 

1.0E 3 

5.2E 4 

5.2E 4* 

1.6E 3 

2.IE 3 

3.IE 4 

1.0E 3 

2.IE 3 

4.IE 3 

1.0E 2 

5.2E 1 

3.IE 1 

5.2E 5* 

3.IE 3 

1.6E 4 

6.IE 3* 

4.6E 3* 

L IE 2* 

6.9E 1* 

2.5E 1* 

2.IE 2 

4.5E 1* 

3.3E 3 

3.0E 3 

L IE 5 

1.3E 3 

1.2E 3* 

2.3E 2* 

8.7E 1* 

2.IE 1* 

1.4E 2* 

1.3E 2 

8.4E 1 

1.4E 1* 

5.9E 2* 

9.8E 1* 

1000 

1000 

100 

10 

10 

10 

10 

10 

100 

1000 

1000 

1000 

1000 

100 

10 

10 

100 

10 

10 

10 

1000 

100 

10 

E-22 
P.52 

Radionuclide 

Rhodium-107 

P Rubidium-79 

— Rubidium-81m 

Rubidium-81 

• Rubidium-82m 

Rubidium-83 

H Rubidium-84 

— Rubidium-86 

• Rubidium-88 

j | Rubidium-89 

Rubidium-87 

I Ruthenium-94 

Ruthenium-97 

• Ruthenium-103 

fl Ruthen ium-105 

Ruthenium-106 

1 Samarium-141m 

Samarium-141 

m Samarium-142 

• Samarium-145 

Samarium-146 

m Samarium-147 

Samarium-151 

• Samarium-153 

Atom. 

No. 

45 

37 

37 

•37 — 

37 

37 

37 

37 

37 

37 

37 

44 

44 

44 

44 

44 

62 

62 

62 

62 

62 

62 

62 

62 

APPENDIX E (Continued) 

Ingestion 

(food) 

1.8E 6 

9.9E 5 

3.6E 6 

-8.4E 4 

1.5E 4 

2.0E 1* 

2.0E 1* 

2.5E 1* 

6.4E 5 

1.5E 6 

3.0E 1* 

2.2E 5 

1.3E 3 

7.8E 1* 

1.1E 4 

6.IE 0 

7.6E 5 

2.8E 6 

6.3E 4 

1.8E 2* 

3.0E-1 

6.0E-1 

3.0E 2 

4.6E 2* 

Release Values 

Ingestion 

(water) 

> E 9 // 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

> E 9 

6.0E 3 

1.8E 2 

> E 9 

1.5E 1 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

E-23 

(Ci) — 

Inhalation 

1.0E 

5.2E 

1.6E 

2.6E 

1.0E 

5.2E 

4.IE 

4.IE 

3.IE 

5.2E 

1.0E 

2.IE 

5.2E 

3.IE 

5.2E 

5.2E 

5.2E 

1.0E 

1.6E 

2.6E 

2.1E2.1E5.2E 

1.6E 

5 

4 

5 

4 -

4 

2 

2 

2 

4 

4 

3 

4 

3 

2 

3 

0* 

4 

5 

4 

2 

• 2 * 

•2* 

1* 

3 

Direct 

Exposure 

5.6E 3* 

1.2E 3* 

4.8E 3* 

2.9E 2* 

3.9E 1* 

7.3E 1 

5.4E 1 

3.9E 2 

2.9E 3* 

1.3E 3* 

--

1.4E 3* 

1.2E 2* 

7.9E 1 

2.0E 2* 

--

1.0E 3* 

3.4E 3* 

8.2E 3* 

2.5E 6 

--

--

--

1.3E 3 

Final 

RQ (Ci) 

1000 

1000 

1000 

100 

10 

10 

10 

10 

j 

1 

1000 J 

1000 | 

10 | 

1000 | 

i 

1 

100 i 

10 

100 

1 

1000 

1000 

1000 

100 

0.01 

0.01 

10 

100 

1 

i 
P.53 

Radionuclide 

Atom. 

No. 

APPENDIX E (Continued) 

Release Values (Ci). -

Ingestion Ingestion Inha-

(food) (water) lation 

Direct 

Exposure 

Final 

RQ (Ci) 

Samarium-155 

Samarium-156 

Scandium-43 

Scandium-44m 

Scandium-44 

Scandium-46 

Scandium-47 

Scandium-48 

Scandium-49 

Selenium-70 

Selenium-73m 

Selenium-73 

Selenium-75 

Selenium-79 

Selenium-81m 

Selenium-81 

Selenium-83 

Silicon-31 

Silicon-32 

Silver-102 

Silver-103 

Silver-104m 

Silver-104 

Silver-105 

62 

62 

21 

21 

21 

21 

21 

21 

21 

34 

34 

34 

34 

34 

34 

34 

34 

14 

14 

47 

47 

47 

47 

47 

1.5E 6 

5.2E 3 

1.7E 4 

9.-5E 1* 

9.8E 3 

3.IE 1 

2.9E 2* 

2.0E 2 

2.0E 5 

1.4E 5 

2.3E 3 

4.IE 3 

1.6E 1* 

1.8E 1* 

2.0E 5 

1.9E 6 

7.7E 5 

3.3E 4 

5.9E 1 

2.2E 6 

3.4E 5 

5.IE 5 

1.6E 5 

1.1E 2 

v.lg. 

v.lg. 

> E 9 // 

5.6E 2 // 

> E 9 // 

7.2E 1 // 

1.1E 3 // 

2.0E 3 // 

> E 9 // 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

> E 9 // 

1.5E 2 // 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

1.0E 5 

4.7E 3 

1.0E 4 

•3,6E 2 

5.2E 3 

1.0E 2 

1.6E 3 

5.2E 2 

2.6E 4* 

2.IE 4 

5.2E 4 

5.2E 3 

3.IE 2 

3.IE 2 

3.6E 4* 

1.0E 5* 

5.2E 4 

1.6E 4* 

2.6E 0* 

1.0E 5 

5.2E 4 

4.7E 4 

3.6E 4 

5.2E 2 

1.8E 4* 

7.0E 2* 

1.9E 3* 

1,3E 2 

1.3E 2* 

1.8E 1* 

3.7E 2 

1.3E 1* 

7.2E 5 

4.6E 3* 

1.7E 2* 

9.5E 1* 

1.0E 2 

6.IE 4 

1.8E 5 

1.0E 3* 

2.6E 5 

8.8E 2* 

1.5E 3* 

LIE 3* 

2.9E 3* 

8.2E 1* 

1000 

100 

1000 

10 

100 

10 

100 

10 

10Q0 

1000 

100 

10 

10 

10 

1000 

1000 

1000 

1000 

1 

100 

1000 

1000 

1000 

10 

E-24 
APPENDIX E (Continued) 

P.54 

Radionuclide 

Silver-106m 

Silver-106 

Silver-108m 

Silver-llOm 

Silver-Ill 

Silver-112 

Silver-115 

Sodium-22 

Sodium-24 

Strontium-80 

Strontium-81 

Strontium-83 

Strontium-85m 

Strontium-85 

Strontium-87m 

Strontium-89 

Strontium-90 

Strontium-91 

Strontium-92 

Sulfur-35 

Tantalum-172 

Tantalum-173 

Tantalum-174 

Tantalum-175 

Atom. 

No. 

47 

47 

47 

47 

47 

47 

47 

11 

11 

38 

38 

38 

38 

38 

38 

38 

38 

38 

38 

16 

73 

73 

73 

73 

Ingest] Lon 

(food) 

5.9E 

1.4E 

1.8E 

1.5E 

7.2E 

9.0E 

8.4E 

1.2E 

2.6E 

2.0E 

4.7E 

5.9E 

1.6E 

9.7E 

1.3E 

1.7E 

8.2E1.9E 

9.8E 

3.9E 

6.2E 

1.8E 

2.4E 

5.6E 

1 

6 

1 

1 

1* 

3 

5 

1* 

3 

4 

5 

2 

6 

1 

5 

1* 

• 1 * 

3 

3 

0* 

6 

5 

6 

4 

Release Values 

Ingestion 

(water) 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

4.8E 2 // 

> E 9 // 

> E 9 // 

> E 9 // 

8.4E 7 // 

(Ci) 

Inhalation 

3.6E 

l.OE 

l.OE 

4.7E 

4.7E 

4.IE 

4.IE 

3.IE 

2.6E 

5.2E 

4.IE 

2.IE 

3.IE 

l.OE 

5.2E 

5.2E 

2.IE 

2.IE 

3.6E 

2.IE 

5.2E 

l.OE 

4.7E 

5.2E 

2 

5 

1* 

1 

2 

3 

4 

2 

3 

3 

4 

3 

5 

3 

4 

1 

0 

3 

3 

1 

5 

5 

5 

4 

Direct 

Exposure 

1.4E 

2.IE 

2.2E 

1.3E 

1.5E 

3.8E 

7.IE 

--

1.5E 

4.IE 

1.3E 

1.3E 

2.7E 

7.2E 

6.8E 

4.5E 

--

7.9E 

1.7E 

--

8.0E 

4.9E 

9.6E 

1.9E 

1* 

3* 

1 

1* 

3 

2* 

3* 

1* 

2* 

3* 

2* 

3* 

1* 

2* 

6 

1* 

2* 

2* 

2* 

2* 

2* 

Final 

RQ (Ci) 

10 

1000 

10 

10 

10 

100 

1000 

10 

10 

100 

1000 

100 

1000 

10 

100 

10 

0.1 

10 

100 

1 

100 

100 

100 

100 

E-25 
APPENDIX E (Continued) 

Release Values (Ci) 

Radionuclide 

Tantalum-176 

Tantalum-177 

Tantalum-178 

Tantalum-179 

Tantalum-180m 

Tantalum-180 

Tantalum-182m 

Tantalum-182 

Tantalum-183 

Tantalum-184 

Tantalum-185 

Tantalum-186 

Technetium-93m 

Technetium-93 

Technet ium-94m 

Technetium-94 

Technetium-96m 

Technetium-96 

Technet ium-97m 

Technetium-97 

Technetium-98 

Technetium-99m 

Technetium-99 

Technetium-101 

Atom. 

No. 

73 

73 

73 

73:; 

73 

73 

73 

73 

73 

73 

73 

73 

43 

43 

43 

43 

43 

43 

43 

43 

43 

43 

43 

43 

Ingestion 

(food) 

4.8E 

2.0E 

1.2E 

4 

4 

7 

____fi_lE:3 

2.4E 

3.0E 

7.2E 

2.6E 

9.5E 

2.2E 

3.5E 

2.7E 

7.0E 

7.6E 

1.7E 

1.3E 

1.7E 

1.8E 

1.3E 

8.9E 

2.2E 

9.7E 

8.9E 

2.7E 

5 

2 

7 

2 

2 

4 

6 

7 

5 

4 

5 

4 

6 

2 

2* 

2* 

1* 

4 

1* 

6 

Ingestion 

(water) 

1.3E 

1.2E 

> E 

L5E 

5.6E 

> E 

> E 

6.2E 

2.6E 

2.4E 

> E 

> E 

> E 

> E 

> E 

> E 

> E 

7.3E 

4.0E 

2.9E 

7.3E 

> E 

2.9E 

> E 

9 // 

4 // 

9 // 

3*// : 

9 // 

9 // 

9 // 

1 // 

2 // 

8 // 

9 // 

9 // 

9 

9 

9 

9 

9 

2 

2 

3 

1 

9 

2 

9 

Inhalation 

5.2E 

l.OE 

3.6E 

:: 4.7E 

3.IE 

l.OE 

2.IE 

5.2E 

5.2E 

2.6E 

3.IE 

l.OE 

l.OE 

3.6E 

2.IE 

l.OE 

l.OE 

l.OE 

5.2E 

3.IE 

1.6E 

l.OE 

3.6E 

1.6E 

4 

5 

5 

3 -

5 

2* 

6 

2 

3 

4 

5 

6 

5 

4 

4 

4 

5 

3 

2 

3 

2 

5 

2 

5 

Direct 

Exposure 

6.0E 1* 

2.7E 3* 

5.7E 4* 

--:.-.--

1.6E 4* 

--

1.2E 4* 

3.IE 1* 

1.8E 2* 

5.4E 1* 

6.7E 3* 

2.8E 3* 

1.2E 3* 

1.4E 2* 

3.7E 2* 

4.8E 1* 

4.7E 4* 

1.6E 1* 

1.2E 5 

--

2.6E 1 

8.6E 2* 

--

8.IE 3* 

Final 

RQ (Ci) 

10 

1000 

1000 

1000 

1000 

100 

1000 

10 

100 

10 

1000 

1000 

1000 

100 

100 

10 

1000 

10 

100 

100 

10 

100 

10 

1000 

E-26 
P.56 

APPENDIX E (Continued) 

Radionuclide 

Technetium-104 

Tellurium-116 

Tellurium-121m 

Tellurium-121 

Tellurium-123m 

Tellurium-123 

Tellurium-125m 

Tellurium-127m 

Tellurium-127 

Tellurium-129m 

Tellurium-129 

Tellurium-131m 

Tellurium-131 

Tellurium-132 

Tellurium-133m 

Tellurium-133 

Tellurium-134 

Terbium-147 

Terbium-149 

Terbium-150 

Terbium-151 

Terbium-153 

Terbium-154 

Terbium-155 

Atom. 

No. 

43 

52 

52 

52 

52 

52 

52 

52 

52 

52 

52 

52 

52 

52 

52 

52 

52 

65 

65 

65 

65 

65 

65 

65 

Ingestion 

(food) 

4.7E 5 

3.IE 4 

1.6E 1* 

1.6E 2 

2.0E 1* 

1.5E 1* 

3.6E 1* 

2.0E 1* 

7.2E 3* 

2.0E 1* 

2.5E 5 

9.6E 1 

6.8E 4 

3.0E 1* 

3.IE 4 

4.6E 5 

2.7E 5 

4.8E 4 

1.2E 4 

1.5E 4 

2.3E 3 

9.9E 2 

9.2E 2 

6.2E 2 

Release Values 

Ingestion 

(water) 

> E 9 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

(Ci) 

Inhalation 

3.6E 

l.OE 

l.OE 

1.6E 

l.OE 

l.OE 

2.IE 

1.6E 

l.OE 

l.OE 

3.IE 

2.IE 

2.6E 

l.OE 

2.6E 

l.OE 

l.OE 

1.6E 

3.6E 

l.OE 

4.7E 

3.6E 

2.IE 

4.IE 

4 

4 

2 

3 

2 

2 

2 

2 

4 

2 

4 

2 

3* 

2 

3* 

4 

4 

4 

2 

4 

3 

3 

3 

3 

Direct 

Exposure 

1.3E 

4.IE 

1.8E 

6.7E 

2.7E 

--

LIE 

5.2E 

2.IE 

7.9E 

LIE 

4.0E 

4.IE 

2.0E 

6.5E 

3.4E 

l.OE 

1.9E 

1.7E 

2.2E 

8.5E 

3.0E 

3.2E 

4.4E 

3* 

3* 

2 

1* 

2 

5 

5 

5 

2 

4* 

1* 

3 

2 

3 

3* 

3* 

2* 

2* 

2* 

1* 

2* 

1* 

2* 

Final 

RQ (Ci) 

1000 

1000 

10 

- -•••• 4 0 

10 

10 

10 

10 

1000 

10 

1000 

10 

1000 

10 

1000 

1000 

1000 

100 

100 

100 

10 

1 

100 

10 

100 

E-27 
P.57 

APPENDIX E (Continued) 

Radionuclide 

Terbium-156m 

(5.0 hr) 

Terbium-156m 

(24.4 hr) 

Terbium-156 

Terbium-157 

Terbium-158 

Terbium-160 

Terbium-161 

Thallium-194m 

Thallium-194 

Thallium-195 

Thallium-197 

Thallium-198m 

Thallium-198 

Thallium-199 

Thallium-200 

Thallium-201 

Thallium-202 

Thallium-204 

Thorium-226 

Thorium-227 

Thorium-228 

Thorium-229 

Thorium-230 

Atom. 

No. 

65 

65 

65

 ! 

65 

65 

65 

65 

81 

81 

81 

81 

81 

81 

81 

81 

81 

81 

81 

90 

90 

90 

90 

90 

Ingestion 

(food) 

3.9E 4 

3.0E 3* 

--• l.OE 2 

1.5E 3 

3.0E 1 

2.8E 1* 

1.7E 2* 

8.7E 5 

5.2E 6 

5.IE 5 

2.4E 5 

1.5E 5 

3.6E 4 

7.9E 4 

3.IE 3 

3.2E 3 

2.4E 2 

6.0E 1* 

9.2E 5 

5.0E 1 

1.8E 0 

1.8E-1 

1.2E 0 

Release Values 

Ingestion 

(water) 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

(Ci) — 

Inhalation 

1.6E 4* 

4.IE 3 

5.2E 2 

1.6E 2* 

l.OE 1* 

l.OE 2 

l.OE 3 

l.OE 5 

3.IE 5 

5.2E 4 

5.2E 4 

2.6E 4 

1.6E 4 

4.IE 4 

5.2E 3 

l.OE 4 

2.6E 3 

l.OE 3 

5.2E 2* 

1.6E 0* 

5.2E-2* 

4.7E-3* 

3.1E-2* 

Direct 

Exposure 

1.4E 5 

--

2.5E 1* 

--

4.9E 1 

3.4E 1 

5.IE 3 

5.4E 2* 

1.5E 3* 

8.2E 2* 

8.2E 2* 

3.IE 2* 

8.3E 1* 

5.7E 2* 

4.7E 1* 

2.IE 3* 

9.2E 1* 

--

1.7E 5 

4.5E 2 

--

--

--

Final 

RQ (Ci) 

1000 

1000 

10 

100 

10 

10 

100 

100 

1000 

100 

100 

100 

10 

100 

10 

1000 

10 

10 

100 

1 

0.01 

0.001 

0.01 

E-28 
P.58 

Radionuclide 

Thorium-231 

J Thorium-232 

_ Thorium-234 

• Thulium-162 

B Thulium-166 

Thulium-167 

• Thulium-170 

_ Thulium-171 

• Thulium-172 

• Thulium-173 

Thulium-175 

• Tin-110 

Tin-Ill 

• Tin-113 

• Tin-117m 

Tin-119m 

• Tin-121m 

Tin-121 

• Tin-123m 

• Tin-123 

Tin-125 

I Tin-126 

Tin-127 

I Tin-128 

Atom. 

No. 

90 

90 

90 

69-

69 

69 

69 

69 

69 

69 

69 

50 

50 

50 

50 

50 

50 

50 

50 

50 

50 

50 

50 

50 

APPENDIX E (Continued) 

Ingestion 

(food) 

1.6E 4 

2.1E-1 

1.4E 2* 

•-•-f-r-.8E 6 

5.IE 3 

1.4E 2* 

2.6E 1* 

3.0E 2 

1.2E 2 

4.7E 3 

2.6E 6 

9.6E 3 

1.1E 6 

6.6E 1* 

1.1E 2* 

9.3E 1* 

8.9E 1* 

2.3E 3* 

7.IE 5 

1.6E 1* 

2.8E 1* 

8.9E 0* 

3.2E 4 

8.7E 4 

Release Values 

Ingestion 

(water) 

v.lg. 

v.lg. 

v.lg. 

> E 9 i t •-•-• 

2.4E 9 // 

3.2E 2 // 

6.2E 1 // 

7.4E 2 // 

6.4E 2 // 

9.7E 8 // 

> E 9 // 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

E-29 

(n \ 

\\Sm. ) 

Inhalation 

3.IE 4 

5.2E-3* 

l.OE 3 

1.6E 5 

5.2E 3 

l.OE 3 

l.OE 2 

1.6E 2* 

5.2E 2 

5.2E 3 

1.6E 5 

5.2E 3 

l.OE 5 

2.6E 2 

5.2E 2 

5.2E 2 

2.6E 2 

5.2E 3 

5.2E 4 

l.OE 2 

2.IE 2 

3.IE 1 

l.OE 4 

1.6E 4 

Direct 

Exposure 

6.0E 2* 

7.3E 5 

7.0E 3 

2.IE 3* 

4.6E 1* 

4.0E 2 

1.3E 4 

--

1.2E 2* 

2.2E 2* 

2.9E 3* 

5.6E 2* 

8.5E 3* 

1.4E 2 

2.7E 2 

— 

--

— 

6.6E 3* 

5.3E 3 

1.4E 2 

2.0E 1 

2.0E 2* 

1.1E 3* 

Final 

RQ (Ci) 

100 

0.001 

100 

- 1000 

10 

100 

10 

100 

100 

100 

1000 

100 

1000 

10 

100 

10 

10 

1000 

1000 

10 

10 

1 

100 

1000 

1 

i 

1 

1 
P.59 

APPENDIX E (Continued) 

Radionuclide 

Atom. 

No. 

Titanium-44 

Titanium-45 

Tungsten-176 

Tungsten-177 

Tungsten-178 

Tungsten-179 

Tungsten-181 

Tungsten-185 

Tungsten-187 

Tungsten-188 

Uranium-230 

Uranium-231 

Uranium-232 

Uranium-233 

Uranium-234 

Uranium-235 

Uranium-236 

Uranium-237 

Uranium-238 

Uranium-239 

Uranium-240 

Vanadium-47 

Vanadium-48 

Vanadium-49 

22 

22 

74 

74 

74 

74 

74 

74 

74 

74 

92 

92 

92 

92 

92 

92 

92 

92 

92 

92 

92 

23 

23 

23 

Ingestion 

(food) 

8.9E 0 

2.8E 4 

3.8E 4 

S.6E 4 

2.3E 2* 

7.6E 6 

6.5E 2* 

6.9E 1* 

8.5E 2 

1.4E 1* 

1.9E 0 

4.9E 3* 

6.0E-1 

3.0E 0 

3.0E 0 

3.0E 0 

3.0E 0 

1.7E 3 

3.0E 0 

1.7E 7 

7.0E 3* 

5.5E 5 

3.2E 1* 

2.2E 3* 

Release Values (Ci) -

Ingestion Inha-

(water) lation 

Direct 

Exposure 

2.2E 1 // 

> E 9 // 

> E 9 // 

> E 9 // 

5. IE 2 // 

> E 9 // 

1.6E 3 // 

1.6E 2 // 

6.0E 4 // 

3.2E 1 // 

v.lg . 

v.lg . 

v.lg . 

v.lg . 

v.lg . 

v.lg . 

v.lg . 

v.lg . 

v.lg . 

v.lg . 

v.lg . 

> E 9 // 

6.9E 1 // 

5.2E 3 // 

3.IE 0* 

1.6E 4* 

2.6E 4 

4.7E 4 

l.OE 4 

l.OE 6* 

1.6E 4 

3.6E 3 

4.7E 3 

5.2E 2 

1.6E 0* 

2.6E 4 

4.1E-2* 

2.1E-1* 

2.1E-1* 

2.1E-1* 

2.1E-1* 

5.2E 3 

2.1E-1* 

l.OE 6 

l.OE 4 

4.IE 4* 

3.IE 2 

l.OE 4 

2.7E 2 

2.IE 3* 

5.7E 2* 

2.2E 5 

1.5E 6 

1.1E 2* 

2.3E 4 

4.IE 4 

5.3E 3 

1.9E 6 

7.5E 5 

2.7E 2 

1.6E 6 

7.2E 2* 

3.5E 5* 

3.4E 5 

3.5E 1 

Final 

RQ (Ci) 

1 

1000 

1000 

100 

100 

1000 

100 

10 

1.00 

10 

1 

1000 

0.01 

0.1 

0.1 

0.1 

0.1 

100 

0.1& 

1000 

1000 

1000 

10 

1000 

E-30 
Radionuclide 

Xenon-120 

• Xenon-121 

_ Xenon-122 

~ Xenon-123 

fl Xenon-125 

Xenon-127 

1 Xenon-129m 

Xenon-131m 

• Xenon-133m 

• Xenon-133 

Xenon-135m 

H Xenon-135 

Xenon-138 

• Ytterbium-162 

• Ytterbium-166 

. Ytterbium-167 

• Ytterbium-169 

Ytterbium-175 

• Ytterbium-177 

• Ytterbium-178 

Yttrium-86m 

I Yttrium-86 

Yttrium-87 

• Yttrium-88 

Atom. 

No. 

54 

54 

54 

54 

54 

54 

54 

54 

54 

54 

54 

54 

54 

70 

70 

70 

70 

70 

70 

70 

39 

39 

39 

39 

APPENDIX E (Continue 

Ingestion 

(food) 

na 

na 

na 

na 

na 

na 

na 

na 

na 

na 

na 

na 

na 

2.IE 6 

2.0E 2 

9.8E 6 

8.2E 1* 

3.7E 2* 

l.OE 5 

7.8E 4 

2.4E 5 

6.7E 2 

2.9E 2 

3.3E 1 

Release Values 

Ingestion 

(water) 

na 

na 

na 

na 

na 

na 

na 

na 

na 

na 

na 

na 

na 

> E 9 

1.2E 3 

> E 9 

1.8E 2 

1.1E 3 

> E 9 

> E 9 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

E-31 

// 

// 

// 

// 

// 

// 

// 

d) 

(Ci) — 

Inhalation 

na 

na 

na 

na 

na 

na 

na 

na 

na 

na 

na 

na 

na 

1.6E 5 

l.OE 3 

3.6E 5 

3.6E 2 

1.6E 3 

2.6E 4 

2.IE 4* 

2.6E 4 

1.6E 3 

1.6E 3 

l.OE 2 

Direct 

Exposure 

l.OE 

2.0E 

7.0E 

6.0E 

2.0E 

l.OE 

2.0E 

4.0E 

l.OE 

l.OE 

9.0E 

l.OE 

4.0E 

2.2E 

4.2E 

1.5E 

1.9E 

LIE 

2.2E 

--

3.9E 

2.3E 

5.IE 

1.4E 

2*+ 

1*+ 

2*+ 

1*+ 

2*+ 

2*+ 

3*+ 

3*+ 

3*+ 

3*+ 

1*+ 

2*+ 

1*+ 

4* 

1* 

4* 

2 

3 

3* 

3* 

1* 

1* 

1* 

Final 

RQ (Ci) 

100 

10 

100 

- io 

100 

100 

1000 

1000 

1000 

1000 

10 

100 

10 

1000 

10 

1000 

10 

100 

1 

1000 

1000 

1 

1 

1000 ' 

10

 ! 

1 

! 

10 

1 

1 

! 

1 
APPENDIX E (Continued) 

P.61 

Radionuclide 

Yttrium-90m 

Yttrium-90 

Yttrium-91m 

Yttrium-91 

Yttrium-92 

Yttrium-93 

Yttrium-94 

Yttrium-95 

Zinc-62 

Zinc-63 

Zinc-65 

Zinc-69m 

Zinc-69 

Zinc-71m 

Zinc-72 

Zirconium-86 

Zirconium-88 

Zirconium-89 

Zirconium-93 

Zirconium-95 

Zirconium-97 

Atom. 

No. 

39 

39 

39 

39 

39 

39 

39 

39 

30 

30 

30 

30 

30 

30 

30 

40 

40 

40 

40 

40 

40 

Ingests 

(food: 

2.4E 

7. IE 

1.1E 

1.8E 

8.IE 

9.6E 

6.IE 

2.2E 

l.OE 

2.9E 

1.2E 

2.7E 

5.7E 

1.4E 

2.3E 

6.0E 

1.4E 

3.0E 

3.0E 

3.5E 

3.6E 

.on 

) 

4 

1* 

6 

1* 

3 

2 

5 

6 

3 

5 

1* 

3 

5 

4 

2* 

2 

2 

2 

1 

1* 

2 

Release Values 

Ingestion 

(water) 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

5.7E 7 // 

> E 9 // 

3.0E 1 // 

4.4E 6 // 

> E 9 // 

> E 9 // 

2.5E 3 // 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

v.lg. 

(Ci) 

Inhalation 

5.2E 

3.IE 

l.OE 

5.2E 

4.IE 

l.OE 

4.IE 

5.2E 

1.6E 

3.6E 

1.6E 

3.6E 

5.2E 

l.OE 

5.2E 

l.OE 

l.OE 

l.OE 

3.IE 

5.2E 

5.2E 

3 

2 

5 

1 

3 

3 

4 

4 

3 

4 

2 

3 

4* 

4 

2 

3 

2 

3 

0* 

1 

2 

Direct 

Exposure 

3.0E 

--

1.4E 

l.OE 

7.0E 

8.8E 

1.4E 

3.IE 

2.6E 

7.IE 

6.4E 

1.5E 

2.0E 

LIE 

3.IE 

2.2E 

9.6E 

1.6E 

— 

5.0E 

6.9E 

2* 

3* 

4 

2* 

2* 

3* 

3* 

2* 

3* 

1 

2* 

8 

2* 

2 

2* 

1* 

2* 

1 

1* 

Final 

RQ (Ci) 

100 

10 

1000 

10 

100 

100 

1000 

1000 

100 

1000 

10 

100 

1000 

100 

100 

100 

10 

100 

1 

10 

10 

E-32 
P.62 

APPENDIX E (Continued) 

FOOTNOTES 

& The adjusted RQ of one curie applies to all radionuclides not otherwise listed. 

Whenever the RQs found in 40 CFR Part 302.4 and this appendix are in conflict, 

the lowest RQ shall apply. For example, uranyl acetate and uranyl nitrate have 

adjusted RQs shown in 40 CFR Part 302.4 of 100 pounds, equivalent to about onetenth of the RQ level for uranium-238 listed in this appendix. 

E Exponent to the base 10. For example, 1.3E 2 is equal to 130 while 1.3E 3 is 

equal to 1300. 

* Indicates the lowest release value for the specific radionuclide; this value is 

used to determine the proposed RQ group. 

v.lg. Indicates that the sorption coefficient is greater than zero and the release 

value is much greater than that for other pathways. 

// A value for the sorption coefficient of this radionuclide was unavailable and the 

value is conservatively assumed to be equal to zero. 

No gamma rays are emitted or the gamma rays which are emitted have gamma ray 

energies of less than 0.07 MeV and are strongly attenuated in air. No release 

value for the direct exposure pathway was calculated. 

m Signifies a nuclear isomer which is a radionuclide in a higher energy metastable 

state relative to the parent isotope. 

+ The release value was calculated assuming submersion in an airborne cloud. The 

derived air concentration (DAC) is used to estimate the release value for the 

specific radionuclide. 

na An annual limit of intake (ALI) for either ingestion or inhalation (or both) was 

unavailable for this radionuclide. 

>E9 The calculated release value for this pathway is greater than one billion curies. 

NOTE 

In order to determine the final RQ for a radionuclide in units of becquerel, multiply 

the number of curies by 3.7E 10 (1 curie is equal to 3.7E 10 becquerel). 

E-33