Eastern Environmental
Radiation Facility
P.O. Box 3009
Montgomery, AL 36109
EPA 520/5-83-024
September 1983
Radiation
Analytical Capability of the
Environmental Radiation
Ambient Monitoring System
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ANALYTICAL CAPABILITY OF THE ENVIRONMENTAL
RADIATION AMBIENT MONITORING SYSTEM
by
J. A. Broadway
M. Mardis
Eastern Environmental Radiation Facility
U. S. Environmental Protection Agency
P. 0. Box 3009
Montgomery, Alabama 36193
April 1983
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TABLE OF CONTENTS
Foreword iv
List of Figures v
List of Tables vii
1.0 BACKGROUND AND PURPOSE 1
2.0 MAJOR SAMPLING COMPONENTS OF ERAMS 7
2.1 Milk Program 7
2.2 Air Program 7
2.3 Drinking Water Program 10
2.4 Surface Water Program 10
3.0 DOSIMETRY AND RISK ANALYSIS FROM THE ERAMS DATA BASE 14
3.1 Structure and Function of ERAMS Data Base 14
3.2 ERAMSDOSE and Computer Program 14
3.3 Dose and Health Risk Assessment Obtained from a
Single Measurement 15
3.3.1 Surface Water Sample: Rulo, Nebraska 16
3.4 Chinese Nuclear Test: September 1976 20
3.5. Chinese Nuclear Test: September 1977 21
3.5.1 Dose Estimates for Individuals 21
3.5.2 Collective Dose Calculations 38
3.6 Collective Dose from Ambient Radionuclide Concentrations . 45
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4.0 OBSERVATION OF SHORT-TERM AND LONG-TERM ENVIRONMENTAL
RADIOACTIVITY TRENDS 47
4.1 Short-Term Trends in Environmental Radioactivity 47
4.2 Long-Term Trends in Environmental Radioactivity 50
5.0 SUMMARY 61
References 62
m
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FOREWORD
This document provides an introduction to the information available
from the Environmental Radiation Ambient Monitoring System (ERAMS) data
base. The types of information which may be derived from these data
include documentation of ambient environmental radiation levels with their
trends, and estimates of dose and health effects due to these ambient
levels.
We hope the technical community concerned with radiation hazards, as
well as the general public, may gain an understanding of the past,
present, and future levels of ambient radiation from information produced
in this and subsequent reports.
Readers are encouraged to send comments regarding the material
presented herein to:
Technical Publications Office
Eastern Environmental Radiation Facility
P. 0. Box 3009
Montgomery, AL 36193
Charles R. Porter, Director
Eastern Environmental Radiation Facility
IV
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LIST OF FIGURES
2.1-1 Pasteurized Milk Sampling Sites ............
2.2-1 Air and Precipitation Sampling Sites
2.2-2 Krypton-85 Sampling Sites
2.3-1 Drinking Water Sampling Sites • •
2.3-2 Surface Water Sampling Sites •
3.3-1 Gross Beta in Airborne Particulates: September 23, 1977
3.3-2 Gross Beta in Airborne Particulates: September 25, 1977
3.3-3 Gross Beta in Airborne Particulates: September 27, 1977
3.3-4 Gross Beta in Airborne Particulates: September 29, 1977
3.3-5 Gross Beta in Airborne Particulates: October 1, 1977 .
3.3-6 Gross Beta in Airborne Particulates: October 14, 1977 .
3.3-7 1-131 in Pasteurized Milk: September 25-October 1, 1977
3.3-8 1-131 in Pasteurized Milk: October 2-October 8, 1977 .
3.3-9 1-131 in Pasteurized Milk: October 9-October 15, 1977 .
3.3-10 1-131 in Pasteurized Milk: October 15-October 22, 1977
3.3-11 1-131 in Pasteurized Milk: October 23-October 29, 1977
3.3-12 1-131 in Pasteurized Milk: October 30-November 5, 1977
3.3-13 1-131 in Pasteurized Milk: November 6-November 30, 1977
8
9
. 11
. 12
. 13
. 22
. 23
. 24
. 25
. 26
. 27
. 28
. 29
. 30
. 31
. 32
. 33
. 34
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3.3-14 1-131 in Pasteurized Milk: December 12-December 31, 1977. . 35
3.3-15 Net 1-131 Concentration in milk - Anchorage, AK 39
4.1-1 U-234 and U-238 in Airborne Participates, Lynchburg, VA . . 48
4.1-2 U-235 and U-238 in Airborne Participates, Lynchburg, VA . . 49
4.1-3 1-131 and Cs-137 in Pasteurized Milk - Network Averages . . 51
4.1-4 1-131 in Pasteurized Milk - Hartford, CT 52
4.1-5 1-131 in Pasteurized Milk - Baltimore, MD 53
4.1-6 Krypton-85 in Air Samples 54
4.1-7 H-3 in Surface Water 55
4.1-8 H-3 in Drinking Water 56
4.2-1 H-3 in Surface Water at Doswell, VA 58
4.2-2 Sr-90 in Pasteurized Milk 59
4.2-3 Cs-137 in Pasteurized Milk 60
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LIST OF TABLES
1 ERAMS Sampling Stations 2
2 ERAMS Sample Radiochemical Analyses 3
3 Co-60 70 Year Dose Equivalent Rates Due to a Lifetime
Ingestion at a Rate of 1.0 Picocurie Per Year 17
4 Committed Dose Equivalent in Target Organs Due to
Ingestion of 8000 Picocurie of Co-60 and Organ Dose
Equivalent Weighting Factors Used to Calculate the
Weighted Mean Committed Dose Equivalent 18
5 Health Effects Estimates for the U.S. Population
for the Chinese Nuclear Test of September 17, 1977 .... 44
6 Collective and Individual Doses from Milk Ingestion,
Air Inhalation and External Exposure Pathways 46
VI 1
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1.0 BACKGROUND AND PURPOSE
Continuing surveillance of radioactivity levels in the United States
is maintained through EPA's Environmental Radiation Ambient Monitoring
System (ERAMS). This system was formed in July 1973 from the
consolidation and redirection of separate monitoring networks formerly
operated by the U.S. Public Health Service prior to EPA's formation.
These previous monitoring networks had been oriented primarily to
measurements of fallout. They were modified by changing collection and
analysis frequencies and sampling locations and by increasing the analyses
for some specific radionuclides. The emphasis of the current system is
toward identifying trends in the accumulation of long-lived radionuclides
in the environment. However, ERAMS, by design, is flexible and can
provide short-term assessments of large scale contaminating events such as
industrial releases or fallout.
ERAMS normally involves several thousand individual analyses per year
on samples of air particulates, precipitation, milk, and surface and
drinking water. Samples are collected at about 280 locations in the
United States and its territories, mainly by State and local health
agencies (See Table 1). These samples are forwarded to ORP's Eastern
Environmental Radiation Facility (EERF) in Montgomery, Alabama for
analyses. ERAMS data are tabulated quarterly and issued to the groups
involved in the program.*
* ERAMS data are published quarterly in the EPA publication
Environmental Radiation Data. A summary analysis of ERAMS data will
be presented in each year's publication of EPA's Radiological Quality
of the Environment in the United States. This publication is
available from the Office of Radiation Programs, U.S. EPA, 401 M
Street S.W., Washington, D.C. 20460. Previously, ERAMS data were
published monthly in Radiation Data and Reports. This publication was
terminated in December 1974.
1
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TABLE 1
ERAMS Sampling Stations
NUMBER
OF
ERAMS COMPONENT STATIONS TYPE OF SAMPLE
SAMPLING
FREQUENCY
Airborne Participates
and Precipitation
Participates
Precipitation
67
Filters from positive
displacement air samplers
Precipitation
Filters are changed
twice weekly
Collected as precipitation
occurs. Composited into
into single monthly sample
Pasteurized Milk
65 Composite samples representing
> than 80 percent of milk
consumed in major population centers
Monthly
Drinking Water
78 Grab samples from major
population centers or selected
nuclear facility environs
Quarterly
Surface Water
58 Grab samples downstream from
nuclear facilities or from
background sites
Quarterly
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TABLE 2
ERAMS Sample Radiochemical Analysis
ERAMS COMPONENT
Airborne Particulates
and Precipitation
Particulates
ANALYSIS
(1) 5 and 29 hour G.
field estimates
(2) Gross beta
(3) Gamma scans
(4
238D 239D 234..
Pu, Pu, U,
238
U
ANALYTICAL
FREQUENCY
3
(I) Each of twice weekly samples.
(2) Each of twice weekly samples.
(3) All samples showing > 1 pCi/rn
gross beta
(4) Quarterly on composite samples
Precipitation
Krypton-85
Pasteurized Milk
(1) Tritium
(2) Gross beta
(3) Gamma scans
(4; 238Pu, 23
235U, 238U
234
(1) 85Kr
1)
141
137Cs, 40K
Ba,
(2) 8ySr, 90Sr, Ca
(3) 89Sr, 90Sr
(4) Tritium
(5) 14C
U,
(1) Monthly on composite sample
(2) Monthly on composite sample
(3) Monthly on composite samples
showing > 10 pCi/1 gross beta
(4) Annually on Spring quarter
composites
!1) Annually
(1) Monthly
(2) Annually on July samples
(3) January, April, and October-
intraregional composites
each of EPA's 10 regions
(4) Annually on April samples
(5) Annually on 9 selected samples
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TABLE 2-Continued
ERAMS Sample Radiochemical Analysis
ERAMS COMPONENT
ANALYSIS
ANALYTICAL
FREQUENCY
Drinking Water
(1) Tritium
(2) Gamma scans
(3) Gross alpha and beta
(4) 226Ra
(5) 228Ra
(6) 90Sr, 89Sr
(7) 238Pu, 239Pu,
235U, 238U
(8)
234
U,
(1) Quarterly
(2) Annually on composite samples
(3) Annually on composite samples
(4) Annually on composite samples
(5) Annually on composite samples
with 225Ra between 2-5 pCi/1
(6) Annually on composite samples
(7) Annually on composite samples
with gross alpha >_ 2 pCi/1
(8) Annually on one individual
sample
Surface Water
(1) Tritium
(2) Gamma scans
(1) Quarterly
(2) Annually on Spring samples
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ERAMS is designed to achieve several objectives:
1. provide data on levels of radioactive pollutants for
standard-setting, for verification that standards are met, for
evaluation of the effectiveness of controls, and for determining
environmental trends;
2. provide input to an assessment of the population intake of
radioactive pollutants;
3. provide data for developing dose computational models for national
dose and health risk;
4. monitor pathways for significant population exposure from major
sources of population exposures, such as fallout from atmospheric
nuclear weapons tests;
5. provide data that will be used in the event of an accidental
release of radioactivity to the environment. Such data could
indicate additional sampling needs and other actions required to
evaluate public health and environmental quality.
Since its initiation, the ERAMS have provided data on baseline
radiation levels in the environment. These data have (1) revealed
long-term trends in environmental radiation levels; (2) detected
radioactive releases from fuel-cycle facilities; (3) provided
preoperational environmental radiation levels prior to nuclear facility
installations; (4) allowed the detection and monitoring of fallout from
atmospheric nuclear weapons testing by other countries, and (5) provided
information to assuage public concerns and give an assessment of public
health hazards during periods of fallout or accidental releases of
radioactivity. Data that have been obtained from ERAMS during fallout
episodes have been consistent with the data obtained from other Federal,
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State, and private sampling programs. The ERAMS has provided a continual
radiation "picture" of a large portion of the United States. The present
data base contains historical information which may be used to predict
trends for future environmental radioactivity.
The ERAMS stations are widely dispersed throughout the United States,
covering each geographical region, most individual states, and all major
population centers. Many stations are located in the near-environment of
major potential environmental release points. The present set of stations
in order to effectively measure the wide-scale impact from global events.
Furthermore, the ERAMS structure satisfies all three major objectives
of an environmental monitoring program, as were set forth by the Health
Physics Society's, Ad Hoc Committee on Upgrading the Quality of
Environmental Data (Wa80) (EPA-520/1-80-012):
1. to aid in dose assessment;
2. to determine any trends of radiation dose rates and
radioactivity concentrations; and
3. to reassure members of the public and governmental
organizations.
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2.0 MAJOR SAMPLING COMPONENTS OF ERAMS
2.1 Milk Program
The ERAMS Milk Program is a cooperative effort between ORP of EPA, and
the Dairy and Lipid Products Branch, FDA. It consists of 65 sampling U.S.
Census locations (See Fig. 2.1-1) submitting monthly samples of milk
composited by the volume of milk consumed each at each sampling location.
Using these data we have calculated that the combined sampling covers more
than 80 percent of the milk consumed in major U.S. population centers.
Furthermore, the pasteurized milk sampling program reflects the
radionucl ides in milk received by at least 40 percent of the U.S.
population.
A primary function of the milk program is to obtain current
radionuclide concentrations in milk and determine long-term trends.
Monthly samples are analyzed for 1-131, Ba-140, Cs-137, and potassium. On
a less frequent schedule but at least annually, Sr-89, Sr-90, H-3, 1-129,
stable 1-127, C-14, plutonium, and uranium are determined.
2.2 Air Program
The ERAMS Air Program consists of 67 sampling locations (see Fig.
2.2-1). Each location submits to EERF particulate filters obtained from
continuous sampling in which filters are changed twice a week, and samples
of precipitation as it occurs. We estimate that the air sampling program
reflects the air particulates and precipitation exposure received by 30
percent of the U.S. population.
A gross beta analysis is performed on each air filter and on a aliquot
of each composited monthly precipitation sample. A gamma scan is
performed on air filters if the gross beta in air exceeds 1 pCi per cubic
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Figure 2.1-1. Pasteurized milk sampling sites
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Figure 2.2-1. Air and precipitation sampling sites
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meter and on precipitation samples if the gross beta in water exceeds 10
pCi per liter. Precipitation samples are also analyzed for tritium, and a
composite of the March through May samples is analyzed for plutonium and
uranium each year. Quarterly composites of the air particulate filters
are analyzed for plutonium and uranium. On a semiannual basis, dry
compressed air samples are purchased at 12 locations from commercial air
suppliers and shipped to EERF and analyzed for Kr-85 (see Fig. 2.2-2).
2.3 Drinking Water Program
Quarterly grab samples are taken at 78 sites that represent the
drinking water of major population centers (see Fig. 2.3-1). These
samples are analyzed quarterly for tritium and annually for gamma, gross
alpha, gross beta, radium, strontium, plutonium, uranium, and iodine.
2.4 Surface Water Program
Surface water grab samples are collected quarterly at 58 locations
(see Fig. 2.3-2). These samples are obtained from surface water sources
located near the first point of public use downstream of major nuclear
facilities that are present or potential sources of drinking water to
large populations. These samples are analyzed quarterly for tritium and
gamma scanned annually in the spring to measure radionuclide washout from
the atmosphere.
10
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Figure 2.2-2. Krypton-85 sampling sites
11
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Figure 2.3-1. Drinking water sampling sites
12
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Figure 2.3-2. Surface water sampling sites
13
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3.0 DOSIMETRY AND RISK ANALYSIS FROM THE ERAMS DATA BASE
3.1 Structure and Function of the ERAMS Data Base
ERAMS is structured to aid in assessing individual and collective dose
and risk to populations. The ERAMS data base provides EPA the ability to
assess the hazards technologically enhanced radiation levels (such as
industrial operations that elevate environmental radiation levels) and
short-term regional or global impact (such as waterborne unplanned release
events and atmospheric fallout episodes). Concentrations are measured
through human receptor pathways and, ultimately, dose and health impact
are calculated. This capability is a distinctive feature of the ERAMS
network and its associated technical support.
3.2 ERAMSDOSE and Computer Program
The methodology for analyzing ERAMS data may be applied to assess
short-term events or persistently elevated environmental concentrations of
radionuclides. The steps in performing a dose assessment are as follows:
1. The assessment location(s), time interval, and sample media are
defined.
2. Concentrations for each sample type and location are generated.
This may be done either on a gross activity basis or by employing
a background subtraction procedure to remove ambient
concentrations from the gross values. At this point the analysis,
plots or colors graphical displays may be produced to show the
time dependency of the measured levels. These data are passed to
the next step for calculation of dose and risk values.
14
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3. Next, media concentrations integrated over time are calculated
from the concentration profiles. These are used to estimate
inhalation or ingestion of radionuclides by people.
4. Data on the time-integrated activity for each exposure pathway are
then used with an environmental pathways model to calculate the
movement of the radionuclides to human receptors.
5. Dose equivalent and risk factors are then applied in these ERAMS
assessments. Dose equivalent factors are based on
state-of-the-art dosimetry, and risk factors are obtained from
current version of the RADRISK (Du80) computer code.
3.3 Dose and Health Risk Assessment Obtained from a Single Measurement
Instances of samples with atypically high concentrations as measured
by ERAMS generally fall into one of two categories. Sampling may be
raised above ambient levels for an extended period such as following an
atmospheric fallout event or a single sample may be atypically high, as
that obtained from a quarterly river sample. This section presents an
example of how an assessment may be made of a single atypically high
measurement using the ERAMS dosimetry and health risk methodology.
Past examples of such assessments include estimation of health impacts
of the radionuclides from volcanic ash, response to specific State Health
Department requests for sample analysis, and calculation of dose and
health risk from uranium, thorium and radium in drinking water. The
specific example presented below is for a water sample collected at Rulo,
Nebraska in 1980 by the surface water network of ERAMS.
15
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3.3.1 Surface Water Sample: Rulo, Nebraska
The quarterly surface water grab sample had a measured Co-60
concentration of 22 pen/liter. We assumed that the measured Co-60
concentration persisted for 6 months. (3 months previous to and 3 months
subsequent to the collection). ICRP Publication 23 (ICRP75) gives a daily
fluid intake of 1.95 liters (2 liters was used for this calculation) with
almost all the fluid intake being from tap water and water based drinks.
Therefore, an individual is assumed to ingest 8000 picocuries of Co-60 in
6 months (22 pci/1 ' 2 I/day ' 182.5 days). The calculation is
conservative because all Co-60 is assumed to be in the soluble form and
all the fluid intake for six months is assumed to contain Co-60 at a
concentration of 22 pCi/1.
Dose equivalent and risk factors for Co-60 (see Table 3) were obtained
using the RADRISK computer code (Du80). Committed dose equivalents in
target organs due to the ingestion of 8000 pCi of Co-60 were used to
calculate the weighted mean committed dose equivalent. We calculated
"weighted mean" dose equivalents by using organ dose equivalent weighting
factors developed by EPA and summing the results (See Table 4).
16
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Table 3
Co-60 70 Year Dose Equivalent Rates Due to a Lifetime Ingestion
at a Rate of 1.0 Picocurie Per Year (f]_ = 5.0E-02 = fraction
from GI tract that goes to blood)
Target
Organ
Red Marrow
Endosteal
Pulmonary
Breast
L i ve r
Stomach Wall
Pancreas
LLI Wall
Kidneys
Bladder Wall
ULI Wall
SI Wall
Ovaries
Testes
Spleen
Uterus
T hymu s
Throid
Total (Somatic)
70-year Dose
Equivalent Rate
(mrem/yr)
5.37E-06
3.92E-06
2.75E-06
4.20E-06
8.53E-06
5.34E-06
6.03E-06
4.02E-05
5.74E-06
6.15E-06
2.03E-05
1.21E-05
1.24E-05
3.73E-06
5.00E-06
1.05E-05
5.61E-06
3.01E-06
17
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Table 4
Committed Dose Equivalent in Target Organs Due to the Ingestion of
8000 Picocuries of Co-60 and Organ Dose Equivalent Weighting Factors
Used to Calculate the Weighted Mean Committed Dose Equivalent
Target
Organ
Red Marrow
Endosteal Cells
Pulmonary
Breast
L i ve r
Stomach Wall
Pancreas
LLI Wall
Kidneys
Bladder Wall
ULI Wall
SI Wall
Ovaries
Testes
Spleen
Uterus
Thymus
Thyroid
Weighted mean
Committed Dose Equivalent
(mrem)
4.3E-02
3.1E-02
2.2E-02
3.4E-02
6.8E-02
4.3E-02
4.8E-02
3.2E-01
4.6E-02
4.9E-02
1.6E-01
9.7E-02
l.OE-01
3.0E-02
4.0E-02
8.4E-02
4.5E-02
2.4E-02
4.8E-02
Weighting Factor
0.15590
0.01470
0 . 29080
0.19080
0.07460
0.04150
0.05810
0.03320
0.01660
0.01660
0.01660
0.00830
0.00830
0.00830
0.00830
0.00830
0.00830
0.04050
18
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The weighting factors for each target organ represent the proportion of
the fatal cancer risk resulting from low LET irradiation of the target
organ to the total fatal cancer risk when the whole body is irradiated
uniformly. The method of summing weighted organ dose equivalents is
similar to the approach introduced by the ICRP in publication 26 (ICRP77)
and subsequently designated the effective dose equivalent in publication
28 (ICRP78). The EPA weighting factors were developed for a general
public exposure situation, whereas the ICRP weighting factors are for an
occupational exposure situation.
The Co-60 fatal cancer risk coefficients shown in Table 3 are based on
an ingestion intake existing for the cohort lifetime (71 years average
lifetime expectancy). Therefore, calculated individual risk will be
approximate since the intake only exists for 6 months and not a lifetime.
The actual risk will also depend on the age of individual when the Co-60
was ingested. With these limitations in mind, we calculated an additional
lifetime fatal cancer risk of 1.4E-08 to an individual in the population
who ingests 8000 picocuries of Co-60.
1.24E-05 fatal cancers
risk = 8000 pCi • 5 - 1.4E-08
yr 10 persons • pd'/yr • 71
For perspective, this calculated fatal cancer risk is 9.3E-06 percent of
the American Cancer Society estimated risk of cancer death from all causes
of 0.15 (Ba79). Therefore, we concluded that the observed level of Co-60
in the Rulo, Nebraska water sample does not consitute a significant health
risk. Subsequent radiochemical analysis on the water sample indicated
19
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that essentially all the Co-60 activity was contained in the sediment and
not in the soluble fraction. Therefore, even the very low calculated
individual fatal cancer risk of 1.4E-08 is probably somewhat high. The
capability to analyze such releases serves to avoid unwarranted public
concern and also maintains the technological ability to evaluate larger
and more serious releases. In addition to the analyses of regional events
as described above, the ERAMS data base has also been used to evaluate
large scale short-term releases to the environment.
3.4 Chinese Nuclear Test, September 1976
Following atmospheric weapon tests in September and November of 1976,
EERF personnel examined the ERAMS data that had been collected and
analyzed the U.S. population doses received from I via the milk
pathway. This nuclide and pathway were shown in this and earlier studies
to be critical in terms of dose received. The results of this analysis
were summarized and published in Science (Sm78). The analysis performed
for this event was based on hand calculations of summaries of radionuclide
concentrations obtained from the computer data base. At that time, there
was no comprehensive methodology for calculating doses and health risk
from all relevant environmental pathways. This limitation demonstrated
the need to develop a more complete computer-based calculational method.
Personnel at the EERF developed this needed methodology during 1977 and
1978 and first applied it to the data obtained from the Chinese
atmospheric test of September 1977.
20
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3.5 Chinese Nuclear Test, September 1977
This Chinese nuclear weapons test also resulted in increased
environmental radionucl ide concentrations in the United States. The ERAMS
network again recorded increased radioactivity in airborne particulates
and in the pasteurized milk network. The buildup and depletion of
activity in daily measurements of airborne particulates are shown in Figs.
3.3-1 through 3.3-6 for the dates 9/23/77 through 10/14/77. The
corresponding buildup and depletion of I in pasteurized milk are
shown in Figs. 3.3-7 through 3.3-14 for the dates 9/25/77 through
12/31/77. The ERAMSDOSE computer program that had been developed
previously was used to calculate dose and health risk resulting from this
nuclear test. The application of this methodology is outlined in the
following sections.
3.5.1 Dose Estimates for Individuals
*
Maximum committed dose equivalent to individuals for eight organs
was calculated for each state.
Equations. The equation used for the individual dose calculations is
r2
ID
sao
n=l
24 (C3sn) (DCF3nao:
(Eq. 1)
where
a = summation index for age group (4 age groups)
n = summation index for nuclide (9 nuclides)
*Since the pasteurized milk samples are composited from several milk
supplies in a state, it is possible that higher doses could have been
calculated for an individual who drinks milk from a single dairy or who
drinks unprocessed milk from a single farm. Also, it is possible that air
concentrations of radionucl ides could be higher at a location other than
the sampling location(s) within a state.
21
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Airborne Concentration
pCi/m3
0 to 0.29
Fig. 3.3-1. Gross beta in airborne participates: September 23. 1977
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-
Airborne Concentration
pCi/m3
0 to 0.29
Fig. 3.3-2. Gross beta in airborne participates: September 25, 1977
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Airborne Concentration
pCi/m3
0 to 0.29
0.3 to 0.99
1.0 to 2.99
3.0 to 9.99
10.0 to 30.0
Fig. 3.3-3. Gross beta in airborne particulates: September 27, 1977
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I
Airborne Concentration
pCi/m3
0 to 0.29
rig. 3.3-4. Gross beta in airborne particulates: September 29. 1977
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Airborne Concentration
pCi/m3
0 to 0.29
0.3 to 0.99
1.0 to 2.99
3.0 to 9.99
10.0 to 30.0
Fig. 3.3-5. Gross beta in airborne particulates: October 1, 1977
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•
Airborne Concentration
pCi/m3
0 to 0.29
0.3 to 0.99
1.0 to 2.99
3.0 to 9.99
10.0 to 30.0
Fig. 33-6. Gross beta in airborne particulates: October 14, 1977
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;
•
Concentration pCi/1
Oto 0.49
Fig. 3.3-7. 1-131 in pasteurized milk: September 15 - October 1, 1977
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Concentration pCi/1
0 to 0.49
0.5 to 3.49
Fig. 3.3-8. 1-131 in pasteurized milk: October 2 - October 8, 1977
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Concentration pCi/1
0 to 0.49
0.5 to 3.49
3.5 to 9.99
10.0 to 29.9
30.0 to 1000
Fig. 3.3-9. 1-131 in pasteurized milk: October 9 - October 15. 1977
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Concentration pCi/1
0 to 0.49
0.5 to 3.49
3.5 to 9.99
10.0 to 29.9
30.0 to 1000
Fig. 3.3-10. 1-131 in pasteurized milk: October 15 - October 22, 1977
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Concentration pCi/1
0 to 0.49
0.5 to 3.49
3.5 to 9.99
10.0 to 29.9
30.0 to 1000
Fig. 3.3-11. 1-131 in pasteurized milk: October 23 - October 29, 1977
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3.5 to 9.99
10.0 to 29.9
30.0 to 1000
Fig. 3.3-12. 1-131 in pasteurized milk: October 30 - November 5, 1977
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Concentration pCi/1
0 to 0.49
0.5 to 3.49
Fig. 3.3-13. 1-131 in pasteurized milk: November 6 - November 30. 1977
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Fig. 3.3-14. 1-131 in pasteurized milk. December 12 - December 31. 1977
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o = summation index for organ
p = summation index for pathway (1 for milk,
2 for air inhalation, 3 for air submersion)
s - summation index for state (51 states, including all states
and the District of Columbia)
ID = individual dose for integration period to organ o, for age
sao
group a in state s (mrem)*
C = integrated radionuclide concentration for pathway p,
state s, and nuclide n corrected to sample collection
date (pCi-d/1 for milk or pCi-d/m for air)**
IR = intake rate for pathway p and age group a (1/d for milk;
pa
m /day for air)
DCF _ = dose commitment factor*** for pathway p, nuclide n, age
pnao
group a, and organ o (for milk and air inhalation mrem/
pCi intake; for c
24 = hours in one day
pCi intake; for air submersion mrem/hr per pCi/m
Milk pathway. The milk consumption rates for the individual dose
calculations are the maximum listed in Table 125 of ICRP-23 (ICRP75) for
that age group. After examining the data on radionuclide levels in
pasteurized milk, it was obvious that radionuclide concentrations in milk
*1,000 mrem equals 1 rem. The rem is the product of the absorbed dose
(rads), an assigned quality factor, and other necessary modifying factors
specific for the radiation considered.
**The curie (Ci) is a measure of radionuclide transformation rate. One Ci
equals 3.7 x 1010 transformations per second. There are 10^ piocuries
(pCi) per Ci.
***Dose commitment is the dose which will be delivered during the 50-year
period following radionuclide intake.
36
-------
started increasing in late September and were approaching background again
by November 10. Thus an integration period of September 17 December 1,
1977 (75 days) was chosen for the milk samples.
Inhalation pathway. The air inhalation rates for each age group are
based on averaging* data given in ICRP-23 for that age group. There are
large variations in breathing rates depending on age and amount of
physical activity. The numbers used are based on 16 hours per day of
light activity and 8 hours per day of rest, except for the infant. The
infant breathing rate is based on 10 hours per day of light activity and
14 hours per day of rest.
A review of the radionuclide levels in air showed that the highest
particulate concentrations occurred between September 17 and October 14.
However, the precise integration periods for airborne radionuclides varied
from station to station since the integrations were stopped five days
after the radionuclide concentration in air had returned to near
background levels.
Dose commitment factors. The dose commitment factors used for the
internal dose calculations are an expression for the internal dose that
will be delivered for a unit quantity of radionuclide ingested or
inhaled. The dose factors used for external dose calculations are an
*For the milk pathway, the maximum intake used in the calculations
always occurs for the youngest age within the age group except for the
infant for whom maximum milk consumption occurs at 6 months. The maximum
breathing rate occurs for the oldest age within each age group. Since the
largest contribution to individual doses from all pathways should result
from i^li in milk, it was decided to use the maximum milk consumption
and the average air consumption to represent the critical receptor in each
age group. This approach should be slightly conservative.
O/
-------
expression of the external dose rate per unit concentration of
radionuclide in air. The dose factors for submersion are from the FESALAP
report (AEC73) since they are not given in Regulatory Guide 1.109.
Integrated radionuclide concentrations in milk and air. The
integrated milk and air concentrations* used in Eq. 1 were obtained by
fitting a cubic-spline (Re67) to the radionuclide concentrations measured
in ERAMS samples and numerically integrating the resulting curve, which
expresses radionuclide concentrations vs. time. A representative curve
for I concentrations in milk at Anchorage, Alaska is shown in
Fig. 3.3-15. A state average value was obtained by an arithmetic average
of the data for each location in each state.
Discussion of calculated doses. The state average integrated
concentrations are used with equation 1 to compute the individual doses
discussed in this report. The maximum bone dose and lung doses are each
approximately 25 percent of the maximum thyroid dose, and the maximum
liver dose and kidney dose are each approximately 5 percent of the maximum
thyroid dose. Thus the thyroid dose is dominant, but doses to bone and
lung are within an order of magnitude of the thyroid dose.
3.5.2 Collective Dose Calculations
Collective dose is computed by summing the individual doses for all
members of a population. It has units of persons times dose (person-rem).
for m11k' Gross concentrations were used for air
available concentratlons of sP*cific radionuclides are not
38
-------
Fig. 3.3-15. Net 131-1 concentration in milk - Anchorage, AK
-------
Equation for collective dose. The equation used to calculate state
collective dose for each organ is
2 4
L. T^
T~r~~
PD = \ \
so \ \
f-L\
n=l a=l
^
(1000) (C. ) (MC ) (f, ) (DCF. )
Isn s la Inao
(n) (p)
+ (.001) (C2sn) (Ps ) (f2a) [(IR2a)
d=l
+ (24) (
(Eq. 2)
where:
PD = state collective dose to organ during the period
September 17 - December 1, 1977 (man-rems)
1000 = conversion factor (Ibs. - rem/Mlbs.-mrem)
.001 = conversion factor (rem/mrem)
d = summation index for food group (2 food groups)
MC = total fluid milk and fluid milk products consumed in
state during integration period
(Mlbs. consumed or committed for consumption)
f . = fraction of milk used for food group d (dimensionless)
f = for milk, fraction of total milk consumption used by age
pa
group a; for air, fraction of total state population in age
group a (dimensionless)
DCF = dose commitment factor for pathway p, nuclide n, age
group a, and organ o (for milk, man-mrem/pCi ingested;
for air inhalation, mrem/pCi inhaled; for air submersion,
•3
mrem/hr per pCi/m )
x = radioactive decay constant for nuclide n (d"1)
td = time between sample collection and consumption (d)
D = days in period of integration for milk pathway
40
-------
P = milk density (lbs/1)
P = population in state s (people)
£„,-„, IR~,, 24 and the indexes a, n, o, p, and s have the same
psn pa
definition as for the individual dose calculations, The first line of
equation 2 is for collective dose from milk ingestion and the second line
is for collective dose from air inhalation and submersion.
State milk and air concentrations. The pasteurized milk portion of
the ERAMS network includes 65 sampling locations within the United
States. Radionuclide concentrations in milk were measured for at least
one sampling location in each state following the test.
The integrated milk and air concentrations of each nuclide at each
location were obtained using a cubic spline and numerical integration
techniques as discussed earlier. For states with only one sampling
location, the integrated milk and air concentrations for that location
were used for the entire state. For the states where there were no air
sampling locations, air concentrations from a nearby location were used as
an estimate of air concentrations in the state. For states with more than
one sampling location, an arithmetic average of the data for the locations
in the state was used. There is a limit to the accuracy of these
calculations since it was assumed that one, or in a few cases two, three,
or four, sampling locations represent an entire state.
41
-------
The use of a single sampling location to represent milk consumed in
each state is supported by the following:
(1) The milk samples are a weighted composite of milk from
each major milk processor supplying an area. The
samples represent locally consumed milk whether the
processor obtained it from local or remote suppliers.
(2) Many processors supply the smaller cities and towns in
a state as well as the metropolitan areas where these
milk samples are taken.
The use of a single sampling location to represent air concentrations
in each state is supported by considering the variability in the observed
concentrations between stations. Even in instances of localized rainout,
which lend to yield the sharpest contrast in measurements, within state
variation is generally within the uncertainty of other parameters used in
the calculation. Typically, fallout plumes are widely dispersed after
travelling the great distance from the point of formation in China to the
United States. Thus, the plume of media debris may cover several states
when it enters the U.S., and large variations in radionuclide
concentrations within a single state would not normally be expected.
Other data. The population for each state was estimated as of July 1,
1976, according to the 1978 edition of the Information Please Almanac
(IPA77).
Calculated dose. Using the methods, equation, and data discussed, the
population doses were calculated for each state. The lung, thyroid, and
bone doses were the highest of the organ doses calculated. In general,
lung doses were highest in populations west of the Mississippi River and
in the Southeast. Thyroid doses were highest in the eastern section of
the Midwest, in the northern portion of the Southeast, and in the
42
-------
Northeast. The doses to the bone were highest in populations of eight
states located primarily in the Northern United States.
The highest collective dose to the lung was 18,400 man-rem in
California, while the highest collective dose to the thyroid was 14,000
man-rem in Illinois. The highest collective dose to the bone was 16,300
man-rem in Illinois. For the total U.S. population, the highest doses
were 150,200 man-rem to the lung, 127,700 man-rem to the thyroid, and
107,600 man-rem to the bone. Doses to the other organs considered in
these calculations were from one-fourth to one-tenth of these highest
doses.
Projected health effects. Health effects were estimated for the
thyroid, lung, and the total body (exclusive of lung and thyroid). It was
estimated that about 17 cancers (10 fatal) might occur over the next 45
years as a result of this test (see Table 5). A comparison of these
projected deaths with the deaths due to natural occurrence of cancers from
all causes lends perspective to these calculations. In 1975, 365,700
persons in the U.S. died from all types of cancers (MVSR77). Assuming a
constant death rate, a natural occurrence of 16,456,200 deaths from all
types of cancer would be expected over a 45-year period. Thus, the excess
death rate is about one extra death for every 1,600,000 deaths occurring
from all types of cancer. It is also estimated that there might be 3
additional serious genetic effects to all succeeding generations of the
U.S.
population as a result of this nuclear test. Considering the current
incidence rate of serious genetic effects of 10.7 percent (NAS80), it is
estimated that there might be about 23,000,000 serious genetic effects
from all causes in the U.S. during the next 50 years.
43
-------
TABLE 5
Health Effects Estimates for the U.S. Population for the Chinese Nuclear Test of September 17, 1977
Organ
Somatic health effects per
million man-rem
(EPA73, EPA77c)
Population dose
estimate (man-rem)
Estimated somatic health effects
during the next 45 years due to
this test
Cancer
Death
Cancer
Death
Thyroid (1-131)
Thyroi
than I
Lung
Total
d (other
-131
body**
11*
106
50
350
1.1
10.6
50
139
1.
1.
1.
1.
Total
health
event
11
70
50
72
X
X
X
X
105
Au
105
104
1.2
1.8
7.5***
6.0***
.12
.18
7.5***
2.4***
estimated somatic
effects for this
16.5
10.
2
* This thyroid cancer estimate is approximately six times lower than the number used in EPA's previous
analysis of health effects from nuclear weapons tests (EPA77a). The change is the result of two
factors:
an increase in the plateau length, as a function of time, for expression of excess thyroid cancers for
the 0-2 years old age group; and a factor of ten decrease in the cancer risk per person rad for 1-131
since beta particles for 1-131 were considered less carcinogenic than photon radiation.
** Exclusive of lung and thyroid health effects.
*** The time required for these effects to occur is the lifetime of the exposed population. However, the
majority of these effects should be within the next 45 years.
-------
3.6 Collective Dose from Ambient Radionuclide Concentrations
The basic structure of radiation dosimetry provides for calculation of
doses to target organs from the summation of radioactive emissions from
all nuclides considered. Futhermore, since each target organ has its own
risk value, it is difficult to use collective organ dose as a measure of
combined hazard from the radionucl ides. In spite of these limitations,
the authors felt that tabulation of some concise dosimetric information
was appropriate. For this reason, collective organ doses from milk, air
inhalation, and external exposure pathways were calculated and presented
for the three year intervals 1973-1976 and 1976-1979 and the two year
interval 1979-1981 (see Table 6).
45
-------
TABLE 6
Collective and Indiviudual Doses from Milk Ingestion, Air
Inhalation and External Exposure Pathways
Collective doses over intervals specified
Date Interval
Minimum Dose
(man-rem)
Maximum Dose
(man-rem)
Organ
Receiving
Maximum Dose
July 1973-June 1976
July 1976-June 1979
July 1979-December 1981
4.8 x 103
(Wyoming)
3.3 x 103
(Nevada)
8.9 x 101
(Alaska)
7.3x 105
(New York)
5.3 x 105
(New York)
4.2 x 105
(New York)
Bone
Bone
Bone
Maximum individual dose over the intervals specified
Date Interval (mrem)
Organ
Receiving
Dose
July 1973-June 1976
July 1976-June 1979
July 1979-December 1981
159 (Arkansas)
159 (Arkansas)
93 (Massachusetts)
Bone
Bone
Bone
46
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4.0 OBSERVATIONS OF SHORT-TERM AND LONG-TERM
ENVIRONMENTAL RADIOACTIVITY TRENDS
4.1 Short-Term Trends in Environmental Radioactivity
Examination of the data collected by the ERAMS program has shown
short-term increases in radioactivity in several instances. One example
OOA OO C
is shown for U and U data for Lynchburg, Virginia (Figs. 4.1-1
OOQ
and 4.1-2), compared with U values for the same location. These data
exhibit increases in atmospheric concentrations and also an increase in
the ratios 234U/238U and 235u/238u, which is characteristic of
enriched uranium releases.
The monitoring site under consideration was near the Babcock and
Wilcox fuel fabrication plant in Lynchburg. During 1973-1975, the
monitoring station was on company property and was subsequently moved in
1975 to a point more representative of the airborne exposure to a typical
individual within the population. Although the magnitude of the
concentration at the receptor point was observed to decrease markedly when
the sampler was moved, the characteric pattern typical of enriched uranium
releases is still evident in the data from more recent years.
Another example of short-term increases in radioactivity was observed
following atmospheric fallout events in 1976 and 1977. Network monthly
average values for I in pasteurized milk were clearly elevated
following both these events (see Fig. 4.1-3). In contrast to the behavior
of I, the network averages for Cs in pasteurized milk did not
-------
73 ' 1974 IB
JflK JfiK
JflN
1977' 1978 1979' I960' 1981
JRN JRK JRN JRN JflM
Fig. 4.1-1. U-234 and U-238 in airborne participates--Lynchburg, VA
48
-------
«1
8
P-
g
ff-
8
73 ' 197'4 1975 ' 1976 1977 ' 1978 ' 1979 ' 1980 ' 1981
Jfltl JflH JflN JflN JflH JfiM JflH JflH
'73' 197'4 1975 1976 1977 1978 197S 1980' 1981
JRK JfiS' JflM JftN JflN -fiH JflH JPM
Fig. 4.1-2. U-235 and l'-238 in airborne particulates--
Lynchburg, VA
49
-------
show the abrupt increases. Specific site meteorological conditions
greatly affect washout from the contaminated atmosphere and, ultimately,
the concentration observed in milk and surface atmosphere. This behavior
is clearly observed following the Setpember 1976 episode when heavy
rainfall over the Eastern United States resulted in sharply increased
concentrations of 1-131 in air and milk. The increased concentrations of
1-131 in milk are shown in Fig. 4.1-5 for Hartford, Connecticut and 4.1-6
for Baltimore, Maryland.
4.2 Long-Term Trends in Environmental Radioactivity
Several types of data files contained within the ERAMS data base have
recorded long-term trends in environmental levels. The expected increase
in Kr concentrations in the atmosphere due to nuclear fuel cycle
operations (UNSCEAR77) has been observed (see Fig. 4.1-9). In addition,
3
increased levels of H have been observed in the waters of the Savannah
River and the Tennessee River (Fig. 4.1-10), and in several drinking water
supplies (Fig. 4.1-11). Nationwide average concentrations in surface
streams are also shown in these figures to highlight the local variations.
When nuclear stations begin operating near an existing surface water
station, the discharges of H-3 are recorded in the subsequent water
samples. This effect is demonstrated clearly at the Doswell, Virginia
site when the North Ana station began operation 5.5 miles upstream in
1978. The continual upward trend is clearly visible in Fig. 4.2-1.
The ERAMS data base also has recorded significant decreases in some
environmental radioactivity. Since the period of numerous worldwide
50
-------
731 -974 1975
JflN " JRN
197S 1977 1978 1979 198Q 1981
Fig. 4.1-3. 1-131 and Cs-137 (pCi/Liter)
in pasteurized milk--network averages
51
-------
JRN
JON
JflN
JBN
JRN
Fig. 4.1-4. 1-131 (pCi/Liter) in pasteurized milk--Hartford, CT
52
-------
JS-
3 ' 1974: ' 19
Jflh' JfW
S 1978 1977 19/8 1979 1980 1981
JflU JBH JRN JftH JRN JfllJ
Fig. 4.1-5. 1-131 in pasteurized milk—Baltimore, MD
53
-------
s
g
eU.. aa
I.DO
Fig. 4.1-6. Krypton 85 in air samples
54
-------
73' 1974: 1975 ' 1976 ' 1977 ' 1978 ' 1979 1980 1981
JflN JflN JflN JRN JflN JflN JRN JflN
a. Kingston, TN
in Surf*oe H«t«r
731 197'4 1975 ' 1976 ' 1977 1978 1979 1980 1981
JflN JflN JflN JRtf JflN JflN JflN JflN
b. Savannah River
Fig. 4.1-7. H-3 in surface uater
55
-------
73 1974 197S 1976 19/7 la/9 1979 1980 1981
JflH JflN Jfli-i JBN JHN JflN JflN J«N
a. Kingston, TN
b.
Savannah River
Fig. 4.1-8 H-3 in drinking water
56
-------
atmospheric weapon tests in the 1950's and 1960's, the environmental
concentration of several important fission products has decreased
90
sharply. One example is a decrease in the concentration of Sr in milk
as shown in Fig. 4.2-2. Also, concentrations of the prominent fission
137
product, Cs, in pasteurized milk have dramatically decreased since
the cessation of atmospheric weapons test (see Fig. 4.2-3). Such sharp
decreases are quite significant when realizing the corresponding decrease
in collective dose to populations.
57
-------
73M97H ' 1975 ' 19'
JflN JflN
is'
?7 19"
JflN
'8 ' 1979 1980 ' 1981
JflH OR!-' J«N
Fig. 4.2-1. H-3 in surface water at Doswell, VA
58
-------
SR-80 pCi/Liter [H PflSTEURIZED MILK
1963 1966 1969 19/2 1975 1978 1981 1964
Fig. 4.2-2. Sr-90 in pasteurized milk
59
-------
LD
CM_
rtCr>_
<_r
a
CD
a"
Ce-137 pCi/Liter CH PflSTEURIZED MILK
1963 1966 1969
Fig. 4.2-3. Cs-137 in pasteurized milk
60
-------
5.0 SUMMARY
The ERAMS program is composed of a network of sampling stations
throughout the United States plus an associated radioanalytical and
assessment support group. These components provide a capability to
evaluate environmental consequences from both normal ambient
concentrations of radiation and time dependent changes as measured by the
samples. The program is structured to measure concentrations of
radionucTides in air, milk, surface water, and drinking water and to
estimate dose and health impact. Several examples of short-term and
long-term assessments of dose and health effect calculations from the
ERAMS data base have been presented in this report.
In order to give the reader some perspective for ambient doses
received by the U.S. population, Table 6 was prepared to show doses to
organs receiving the highest organ doses from milk, inhalation, and
external exposure. These displays produced for two-year intervals show
slowly decreasing organ doses for the later years. Contributions from
K are shown to be a signifcant contribution to the total dose
received. Based on these assessments, we may state that the U.S.
population has not been subjected to significant doses from the
radionuclides introduced by mankind into the receptor pathways measured by
ERAMS. Furthermore, measurements of a variety of other pathways in
previous studies have shown that no pathways of significance were omitted.
-------
REFERENCES
AEC73 U.S. Atomic Energy Commission, Final Environmental Statement
Concerning Proposed Rule Making Action: Numerical Guides for
Design Objectives and Limiting Conditions for Operation to Meet
the Criteria: As Low As Practicable for Radioactive Materials in
Light Water Cooled Nuclear Power Reactor Effluents. Vol. 2,
Analytical Models and Calculations WASH-1258, Directorate of
Regulator Standards (July 1973).
Ba79 Battist, L., Buchanan, J., Congel, F., Nelson, C., Nelson, M.,
Peterson, H., and Rosenstein, M., 1979, Ad Hoc Population Dose
Assessment Report, "Population Dose and Health Impact of the
Accident at the Three Mile Island Nuclear Station," a preliminary
assessment for the period March 28 through April 7, 1979
(Superintendent of Documents, U.S. Government Printing Office,
Washington, D.C.).
Du80 Dunning, D.E., Jr., Leggett, R.N., and Yalcintas, M.G., A Combined
Methodology for Estimating Dose Rates and Health Effects for
Exposure to Radioactive Pollutants, ORNL/TM-7105 (1980).
EERF73 Eastern Environmental Radiation Facility, The Environmental
Radiation Ambient Monitoring System, Montgomery, Alabama,
unpublished report, 1973.
EPA76 U.S. Environmental Protection Agency, Radiological Quality of the
Environment, EPA-520/1-76-010, Chapter 2, Washington, DC, (1976).
EPA77 U.S. Environmental Protection Agency, Radiological Quality of the
Environment in the United States-1977, EPA 520/1-77-009 Chapter 2,
Washington, DC,, (1977).
ICRP75 Report of the Task Group on Reference Manual, ICRP-23
International Commission on Radiological Protection, Pergamon
Press (1975).
ICRP77 International Commission on Radiological Protection, 1977,
"Recommendations of the International Commission on Radiological
Protection," ICRP Publication 26 (Pergamon Press, NY).
ICRP78 International Commission on Radiological Protection, 1978,
"Statement from the 1978 Stockholm Meeting of the ICRP, The
Principles and General Procedures for Handling Emergency and
Accidental Exposures of Workers," ICRP Publication 28 (Pergamon
Press, NY).
62
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REFERENCES (continued)
IRC81 International Reference Center for Radioactivity, Data on
Environmental Radioactivity, quarterly reports, BPn °35, 78110
LeVesinet, France (1981).
Ki72 Kirk, W.P., Krypton 85: A Review of the Literature and Analysis
of Radioation Hazards, U.S. Environmental Protection Agency,
Office of Research and Monitoring, Washington, D.C., 1972.
Kl72 Klement, A.W., Jr., Miller, C.P., Minx, R.P., and Shleien, B.,
Estimates of Ionizing Radiation Doses in the United States:
1960-2000. ORP/CSD 72-1, U.S. Environmental Protection Agency,
1972.
MVSR77 Advanced Report on Final Mortality Statistics for 1975, Monthly
Vital Statistics Report, Vol. 25. No. 11 (Supplement), (February
1977).
NAS72 National Academy of Sciences, The Effects on Populations of
Exposure to Low Levels of lonezing Radiation, Report of the
Advisory Committee on the Biological Effects of Ionizing
Radiation, National Research Council, Washington, DC (November
1972).
NAS80 National Academy of Sciences, The Effect on Populations Exposure
to Low Levels of Ionizing Radiation: 1980, Committee on Biological
Effects of Ionizing Radiations, Washington, DC, 1980.
NCR75 National Council on Radiation Protection and Measurements,
Krypton-85 in the Atmosphere-Accumulation, Biological
Significance, and Control Technology, NCRP Report No. 44, 1975.
Re67 Reinsch, C.H., Smoothing by Spline Functions, Numerische
Mathematik 10, 177-183 (1967).
Sm78 Smith, J.M., Broadway, J.A., and Strong, A.B., United States
Population Dose Estimates for Iodine-131 in the Thyroid After the
Chinese Atmospheric Nuclear Weapons Tests, Science, 200, 44-46
(1978).
St77 Strong, A.B., Smith, J.M. and Johnson, R.H., Jr., EPA Assessment
of Fallout in the United States from Atmospheric Nuclear Testing
on September 26 and November 17,, 1976 by the People's Republic of
China, EPA 520/5-77-002 (1977).
Un77 United Nations Scientific Committee on the Effects of Atomic
Radiation, 1977 Report to the General Assembly, p. 203, United
Nations, New York, (1977).
63
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GENERAL REFERENCES
Wa80 Watson, J.E., Upgrading Environmental Radiation Data, Health
Physics Society Committee Report HPSR-1 (1980), EPA-520/1-80-012
(1980).
B179 Blanchard, R.8., Strong A.B., Lieberman, R., and Porter, C.R., The
Eastern Environmental Radiation Facility's Participation in
Interlaboratory Comparision of Environmental Sample Analyses,
ORP/EERF-79-1, 1979.
Fo80 Fowler, T.W. and Nelson, C.B., Health Impact Assessment of
Carbon-14 Emissions from Normal Operations of Uranium Fuel Cycle
Facilities, EPA-520/5-80-004,(1981).
Os73 Oscarson, E.E., Effects of Control Technology on the Projected
Krypton-85 Environmental Inventory, Noble Gas Symposium, Las
Vegas, Nevada, September 24-28, 1973.
Sm82 Smith, J.M., Norwood, D.L., Strong, A.B. and Broadway. J.A., EPA
Assessment of Fallout in the United States from Atmospheric
Nuclear Testing on September 17, 1977 by the People's Republic of
China, EPA 520/5-82-008.
64
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