# Exposure Routes and Pathways

This chapter discusses how the hypothetical receptors receive a
radiation dose from SRS releases by coming into contact with
contaminated media (air, water, soil, and food). The models used to
derive doses from exposure to contaminated media are discussed in a
semi-quantitative fashion, because the details of these models are fully
explained in the Software Design Document (Chapter 10) for the GENII[^1]
code (1). These models do not calculate dose directly, but instead
calculate "intake of radionuclides by each ingestion and inhalation
exposure pathway, and exposure to radionuclides from external exposure
pathways." [Chapter 10](../Chapter_10_ready%20for%20CDC%20031405.doc)
explains how these radionuclide intakes and exposures produce receptor
doses.

This chapter also summarizes the values for the variables chosen to
obtain the point-estimates of radiation dose and risk. Variable values
related to receptor activities, in accordance with the scenarios
discussed in [Chapter 3](../Chapter_03_ready%20for%20CDC%20031405.doc),
are summarized here; the complete rationale for their selection is given
in [Appendix E](../Appendix_E%20ready%20for%20CDC%20031405.doc). Other
variable values not related to receptor activities are detailed in
[Appendix
F](../Appendix_F%20tables%20-%20Ready%20for%20CDC%20031405.doc).

## Introduction

Radionuclide releases from SRS facilities into the air ([Chapter
5](../Chapter_05_Ready%20for%20CDC%20031405.doc)) and water ([Chapter
7](../Chapter_07_Ready%20for%20CDC%20031405.doc)) are transported, by
advection and dispersion in air ([Chapter
6](../Chapter_06_ready%20for%20CDC%20031405.doc)) and water ([Chapter
7](../Chapter_07_Ready%20for%20CDC%20031405.doc)), to various exposure
locations. These transported radionuclide releases produce contaminated
media at the exposure locations ([Chapter
3](../Chapter_03_ready%20for%20CDC%20031405.doc)). Air, water, soil, and
food are the contaminated media investigated in this study.
Contamination of soil and foodstuffs by contaminated air and water is
discussed in [Chapter 8](../Chapter_08_ready%20for%20CDC%20031405.doc).
At the various exposure locations the hypothetical receptors engage in
activities specified in accordance with the scenarios described in
[Chapter 3](../Chapter_03_ready%20for%20CDC%20031405.doc), such as
swimming, breathing, boating, and eating; these activities bring the
receptors into contact with different kinds of contaminated media, which
causes radiation exposure. The three radiation exposure routes
considered in this study are:

1.  INHALATION of contaminated air and contamination resuspended from
    soil

2.  INGESTION of contaminated food, water, and soil

3.  DIRECT EXPOSURE to contaminated air, water, and soil (including
    river sediment)

Although additional exposure routes may be important under some
circumstances, they were not considered important for this dose
reconstruction. For example, absorption of radionuclides through skin
exposed to contaminated air or water is a possible exposure route, but
is typically less than other exposure routes for the same contaminated
media. Thus direct exposure from air immersion and water immersion is
generally more significant than dermal absorption respectively in air
and water for most beta-gamma emitters, such as Ar-41. Direct exposures
by air and water immersion were included in this study, but dermal
exposures were not included. Ingestion of contaminated drinking water
was not included in this study; only inadvertent ingestion of water
while swimming was modeled. The main rationale for this is that the main
body of water directly contaminated by liquid releases from the SRS, the
Savannah River, was not used for drinking water in any of the exposure
scenarios. The Savannah River is used for municipal water supplies far
downstream (e.g., Port Wentworth and Beaufort-Jasper ), but this was not
part of any scenario. Some contamination of local reservoirs near the
SRS probably arose from deposition of airborne radionuclides into the
surface-water basins feeding the reservoirs. However, a model for this
type of contaminant transport was not readily available and the
contamination level measured was found to be small and may not all have
originated from the SRS (e.g., in 1981 the measured concentrations at
the North Augusta Water Plant for undifferentiated alpha activity was
0.4 pCi/L and for undifferentiated beta activity was 3 pCi/L) (2).

A total of eighteen potential exposure pathways were modeled in this
study, as shown in Table 9-1. The Table is organized according to the
exposure route (direct exposure, ingestion, and inhalation) and exposure
pathway; it indicates for each exposure pathway whether the release was
to water or air and the contaminated medium (air, water, soil, or
foodstuffs) causing the exposure. The total dose is obtained by summing
the incremental dose from each exposure pathway.

+--------------------------------------+--------+--------+-----------+
| Table 9‑1 Exposure Routes and        |        |        |           |
| Pathways for Air and Water Pathways  |        |        |           |
+--------------------------------------+--------+--------+-----------+
| Exposure Route & Pathway             | Air    | Water  | Con       |
|                                      |        |        | taminated |
|                                      | R      | R      | Medium    |
|                                      | elease | elease |           |
+--------------------------------------+--------+--------+-----------+
| **Direct Exposure (External          |        |        |           |
| radiation):**                        |        |        |           |
+--------------------------------------+--------+--------+-----------+
| -   Immersion in a plume of air      | X      |        | Air       |
+--------------------------------------+--------+--------+-----------+
| -   Exposure to contaminated soil    | X      |        | Soil      |
+--------------------------------------+--------+--------+-----------+
| -   Exposure to a contaminated       |        | X      | Soil      |
|     shoreline                        |        |        | (         |
|                                      |        |        | sediment) |
+--------------------------------------+--------+--------+-----------+
| -   Exposure to contaminated water   |        | X      | Water     |
|     while swimming                   |        |        |           |
+--------------------------------------+--------+--------+-----------+
| -   Exposure to contaminated water   |        | X      | Water     |
|     while boating                    |        |        |           |
+--------------------------------------+--------+--------+-----------+
| **Ingestion:**                       |        |        |           |
+--------------------------------------+--------+--------+-----------+
| -   Leafy vegetable consumption      | X      |        | Food      |
+--------------------------------------+--------+--------+-----------+
| -   Root vegetable consumption       | X      |        | Food      |
+--------------------------------------+--------+--------+-----------+
| -   Fruit consumption                | X      |        | Food      |
+--------------------------------------+--------+--------+-----------+
| -   Grain consumption                | X      |        | Food      |
+--------------------------------------+--------+--------+-----------+
| -   Beef consumption                 | X      |        | Food      |
+--------------------------------------+--------+--------+-----------+
| -   Poultry consumption              | X      |        | Food      |
+--------------------------------------+--------+--------+-----------+
| -   Milk consumption                 | X      |        | Food      |
+--------------------------------------+--------+--------+-----------+
| -   Egg consumption                  | X      |        | Food      |
+--------------------------------------+--------+--------+-----------+
| -   Inadvertent soil consumption     | X      |        | Food      |
+--------------------------------------+--------+--------+-----------+
| -   Fish consumption                 |        | X      | Food      |
+--------------------------------------+--------+--------+-----------+
| -   Inadvertent ingestion of water   |        | X      | Food      |
|     while swimming                   |        |        |           |
+--------------------------------------+--------+--------+-----------+
| **Inhalation:**                      |        |        |           |
+--------------------------------------+--------+--------+-----------+
| -   Inhalation of contamination in   | X      |        | Air       |
|     the air                          |        |        |           |
+--------------------------------------+--------+--------+-----------+
| -   Inhalation of contamination      | X      |        | Air       |
|     resuspended from soil            |        |        |           |
+--------------------------------------+--------+--------+-----------+

## General Exposure Formula 

Given the concentration of a radionuclide in a contaminated medium, the
exposure models represent how the receptor comes into contact with
radiation in a way that ultimately produces a radiation dose in the
receptor. In particular the end point of these exposure models is to
calculate "intake" of either (1) radioactive material through ingestion
or inhalation routes or (2) radiation exposure from direct external
radiation.

The exposure models determine different information depending upon the
exposure route, as shown in Table 9-2.

Table 9‑2 Intake for Direct Exposure, Ingestion, and Inhalation Exposure
Routes

  ------------------- ---------------------------------------------------
  Exposure Route      Intake Calculated

  Direct Exposure     Annual exposure \[immersion in air (Bq/m^3^) or
                      water (Bq/L); proximity to soil or sediment (Bq/kg)
                      or water (Bq/L); ground plane exposure (Bq/m^2^)\].

  Ingestion           Annual radionuclide activity ingested (Bq in a
                      year).

  Inhalation          Annual radionuclide activity inhaled (Bq in a
                      year).
  ------------------- ---------------------------------------------------

As will be described in [Chapter
10](../Chapter_10_ready%20for%20CDC%20031405.doc), these intake values
will be multiplied by an appropriate dose conversion factor to obtain an
incremental dose; i.e.,

Dose = Intake \* Dose Conversion Factor (9-1)

However, the dose conversion factor depends upon the exposure route, the
radionuclide, and sometimes other factors, such as solubility or lung
clearance class. In addition, dose conversion factors are, in general,
dependent on the age of the receptor. Because the scenario
specifications clearly expressed a concern with the interaction of the
age of the receptors and the time-history of releases from the site,
doses were calculated using age-dependent dose conversion factors. This
age dependency was represented by grouping the dose conversion factors
into four age groups, as shown in Table 9-3:

Table 9‑3 Age Groups Used for Dose Conversion Factors and Risks

  ------------------------------------------------ ----------------------
  Receptor Age Group                               Age Group^\*^

  Infant/ Preschooler                              0 -- 5 year

  School Age Child                                 5 -- 15 year

  Teenager/Young Adult                             15 -- 25 year

  Adult                                            25 -- 70 year
  ------------------------------------------------ ----------------------

> ^\*^Based on the Federal Guidance Report 13 (FRG-13) Cancer Risk
> Coefficients for Environmental Exposure to Radionuclides (3).

More details on dose conversion factors are presented in [Chapter
10](../Chapter_10_ready%20for%20CDC%20031405.doc).

The exact nature of both the intake and the formula used to calculate
the intake depend upon both the exposure route and the specific pathway
described. The general formula for calculating the intake is:

I = C~m~·CR·ED·DAF·AAF (9-2)

Where, I is the intake;

C~m~ is the concentration in the medium;

CR is the contact rate or uptake rate

ED is the exposure duration;

DAF is the daily activity factor;

AAF is the annual activity factor.

Table 9-4 describes each factor in the general intake equation and shows
some examples of units for these various factors.

Table 9‑4 Terms of the General Intake Equation\*

  ---------------- -------------- --------------------- ----------------------
  General Term     Variable       Description           Example Units
                   Abbreviation                         

  Medium           C~m~           Radionuclide          Bq/L water\
  Concentration                   concentration in the  Bq/m^3^ air\
                                  exposure medium.      Bq/kg soil

  Intake/Contact   CR             Ingestion,            L water/d\
  Rte                             inhalation, or        m^3^ air/d
                                  exposure rate.        

  Exposure         ED             Number of years over  Y -- (For this study,
  Duration                        which the exposure is all exposures were
                                  defined.              calculated on an
                                                        annual basis, so this
                                                        was always 1Y.)

  Daily Activity   DAF            Daily activity        hr/d\
  Factor                          pattern parameter     events/d ·\
                                  (e.g. exposure events h/event
                                  per day, hours of     
                                  exposure per day).    

  Annual Activity  AAF            Annual activity       days/year
  Factor                          pattern parameter     
                                  (e.g. days per year   
                                  that exposure         
                                  occurs).              
  ---------------- -------------- --------------------- ----------------------

\*Based on Table 10.1 of the GENII SDD (1).

As stated previously, the methods for calculating the concentrations in
contaminated media are described in other Chapters: [Chapter
5](../Chapter_05_Ready%20for%20CDC%20031405.doc) describes the
calculation for air; [Chapter
7](../Chapter_07_Ready%20for%20CDC%20031405.doc) describes the
calculation for water; [Chapter
8](../Chapter_08_ready%20for%20CDC%20031405.doc) describes the
calculation for food chain media, i.e., soil, plants, and animals. These
concentrations depend upon the time history of releases from the site
and their migration in and uptake by the various media. The other four
factors (variables) in Equation 9-2 depend upon the behavior of the
receptors, as specified by the scenarios. The contact rate for the
ingestion route is the ingestion rate, kg of a particular food ingested
per year. The contact rate for inhalation is the inhalation rate, m^3^
of air inhaled per day. The contact rate for direct exposure is unity.
For this study the exposure duration was one year, since the release
rate (Bq/y) was adjusted for each year and since dose and risk
conversion factors were adjusted for the ages of the receptors. The
daily activity factor and annual activity factor varied depending on the
exposure pathway. For example, for school children, attendance at school
was characterized by a daily activity factor of 7 hours/day spent at
school on a school day and an annual activity factor of 180 days/year of
school attendance. Those variables that depend on receptor behavior,
(e.g., time spent in a particular exposure location), are sometimes
called usage factors. Values for these variables, along with a rationale
for the choice of each value for the point estimate calculation, are
listed in [Appendix E](../Appendix_E%20ready%20for%20CDC%20031405.doc).

Dose to each receptor could have been calculated by specifying the
appropriate variables in Equation 9-2 for every applicable exposure
pathway. However, such a calculation would have been very laborious and
could not be easily automated. As Equation 9-2 indicates, the increment
of dose from any exposure pathway is calculated by multiplying a number
of factors; this property was used to perform an efficient, file-driven
calculation. For each pathway, doses were calculated for an adult on the
basis of a unit contact rate (e.g., 1 kg ingested per year) and/or a
unit exposure duration (e.g., one hour). Then each dose based on unit
inputs was scaled up by a factor representing the actual contact rates
and exposure durations for a particular receptor; in addition, doses
were scaled by adjustment factors accounting for the age-dependent dose
conversion factors. The derivation and computational use of these
exposure factors and adjustment factors are described in Appendices E
and G, respectively. This approach made the calculation of doses more
efficient, but had no effect on the values of the computed doses or the
precision of those estimates.

The following sections briefly discuss the intake models and variables
for each of the three exposure routes modeled.

## Direct Exposure Pathways 

Direct exposure pathways modeled in this study include:

1.  Immersion in a plume of air.

```{=html}
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```
4.  Exposure to contaminated soil.

5.  Exposure to a contaminated shoreline.

6.  Immersion in contaminated water while swimming.

7.  Exposure to contaminated water while boating.

As shown in Table 9-1, the first two exposure pathways are associated
only with radionuclide releases to air, while the last three exposure
pathways are associated only with radionuclide releases to water. Soil
was considered to be contaminated by deposition of airborne
radionuclides. Soil was not considered to be contaminated by deposition
of water-borne radionuclides, because farmers in vicinity of the SRS did
not use the Savannah River and Lower Three Runs Creek for irrigation (as
explained in [Chapter 3](../Chapter_03_ready%20for%20CDC%20031405.doc)).
The Savannah River and Lower Three Runs Creek were the only two water
bodies contaminated by liquid releases from the SRS and accessible to
the public. For exposure to a contaminated shoreline, the contaminated
medium is shoreline sediment, deposited by one of the two water bodies
receiving liquid releases from the SRS.

### Immersion in a Plume of Air 

External exposures from immersion in a contaminated plume of air result
from the receptor absorbing radiation emitted by radionuclides in the
plume. Gamma rays produce most of the immersion dose, although beta and
alpha radiation may also contribute. The receptor is assumed to be at
the center of a hemispherical cloud of radionuclides at a uniform
concentration. Radiation emitted by atoms farther away from the receptor
is more likely to be absorbed by the air and contaminants between the
receptor and the emitting atoms. Therefore, nearby atoms contribute most
to the dose and the dose calculated is not very sensitive to large-scale
variations in concentration. Note that for this study, the use of a
sector average model means the concentration is assumed to be constant
in an entire 22.5º sector (360° divided by 16 sectors) at a given
radius.

Key variables in determining the exposure from immersion in a
contaminated plume of air are (1) the concentration of each radionuclide
at a particular exposure location and (2) the time of exposure for a
particular receptor at a particular location. In general shielding of a
receptor may also be important, but it was conservatively assumed that
indoor air concentrations equaled outdoor air concentrations. The
approach used to calculate yearly air concentrations at various exposure
locations is described in [Chapter
5](../Chapter_05_Ready%20for%20CDC%20031405.doc). The time spent by each
receptor at various locations is provided in Table 9-5.

Table 9‑5 Exposure Times (hours/year) for the Air Immersion Pathway

  ----------------------------------------------------------------------------------------
  Individual          Adult Male Adult      Child Born             Child Born  
                                 Female     in 1955                in 1964     
  ------------------- ---------- ---------- ---------- ----------- ----------- -----------
                                            *Thru      *Starting   *Thru 1981* *Starting
                                            1972\**    1973*                   1982*

  ***Rural Family                                                              
  One***                                                                       

  Girard              8,760      8,760      7,500      8,760       7,500       8,760

  Waynesboro          0          0          1,260      0           1,260*\**   0

  ***Rural Family                                                              
  Two***                                                                       

  Williston           8,760      8,760      8,760      8,760       8,760       8,760

  ***Urban/Suburban                                                            
  Family***                                                                    

  Augusta             6,760      8,760      8,760      6,760       8,760       6,760

  Onsite SRS          2,000      0          0          2,000       0           2,000

  ***Delivery                                                                  
  Family***                                                                    

  Martin              306        306        306        306         306         306

  Onsite SRS          400        0          0          400         0           400

  Allendale           1,600      0          0          1,600       0           1,600

  Barnwell            6,454      8,454      8,454      6,454       8,454       6,454

  ***Outdoors Person                                                           
  Family***                                                                    

  Onsite SRS          2,000      0          0          2,000       0           2,000

  Jackson             6,760      8,760      8,760      6,760       8,760       6,760

  ***Family Near                                                               
  River***                                                                     

  Martin              8,760      8,760      8,760      8,760       8,760       8,760

  ***Migrant Worker                                                            
  Family***                                                                    

  New Ellenton        4,380      4,380      4,380      4,380       4,360       4,380

  \*During the                                                                 
  indicated years                                                              
  (1969-1972 for the                                                           
  Child Born in 1955,                                                          
  and 1978-81 for the                                                          
  Child Born in                                                                
  1964), the children                                                          
  born in 1955 and                                                             
  1964 are classed as                                                          
  teenagers.                                                                   
  ----------------------------------------------------------------------------------------

### Exposure to Contaminated Soil

External exposures from being on a contaminated surface result from the
receptor absorbing radiation emitted by radionuclides in the
contaminated surface. Gamma rays produce most of this dose from a
contaminated surface, also called ground-plane dose. The receptor is
assumed to be standing on a slab of material contaminated at a uniform
concentration. Radiation emitted by atoms on the surface of the slab is
partially absorbed by the air between the receptor and emitting atoms;
radiation emitted by atoms within the slab is partially absorbed by the
intervening air and slab material (usually considered to be soil). More
distant decaying atoms generally contribute less to dose than those
closer to the receptor. The model also considers excitation of
intervening atoms and secondary emission of radiation. Therefore nearby
atoms contribute most to the dose and the dose calculated is not very
sensitive to large-scale variations in concentration. Note that for this
study, the use of a sector average model means the concentration is
assumed to be constant in an entire 22.5º sector at a given radius.

Key variables in determining the intake for exposure to contaminated
soil are:

1.  Concentration of each radionuclide in the soil at a particular
    exposure location.

2.  Time of exposure for a particular receptor at a particular location.

3.  Shielding of a receptor provided by buildings.

4.  Fractions of time spent indoors and outdoors at each exposure
    location.

The approach used to calculate yearly soil concentrations at various
exposure locations is described in [Chapter
8](../Chapter_08_ready%20for%20CDC%20031405.doc). The time spent by each
receptor at various locations is provided in Table 9-6. (Note that the
exposure times in Table 9-6 are smaller than in Table 9-4 because
receptors were assumed not to be exposed to radiation from ground
contamination when they were swimming or boating.) The outdoor shielding
factor was set equal to 1.0 for all scenarios, exposure locations,
individuals, and years; the indoor shielding factor was set to 0.7
([Appendix E](../Appendix_E%20ready%20for%20CDC%20031405.doc)). The
hours spent indoors and outdoors were determined based on data from The
Exposure Factors Handbook (4) and the scenario specifications provided
by CDC (5). From the times spent indoors and outdoors at each location
for each receptor, the fraction of time spent indoors and outdoors was
calculated (these fractions must sum to unity); indoor and outdoor
fractions are summarized in Table 9-7. In addition, [Appendix
E](../Appendix_E%20ready%20for%20CDC%20031405.doc) lists the hours spent
indoors and outdoors for each receptor and exposure location, and the
indoor and outdoor fractions calculated from these hours.

Table 9‑6 Exposure Times (hours/year) for Ground Contamination External
Exposure Pathway

  ----------------------------------------------------------------------------------------
  Individual          Adult Male Adult      Child Born             Child Born  
                                 Female     in 1955                in 1964     
  ------------------- ---------- ---------- ---------- ----------- ----------- -----------
                                            *Thru      *Starting   *Thru 1981* *Starting
                                            1972\**    1973*                   1982*

  ***Rural Family                                                              
  One***                                                                       

  Girard              8,739      8,739      7,479      8,739       7,479       8,739

  Waynesboro          0          0          1,260      0           1,260*\**   0

  ***Rural Family                                                              
  Two***                                                                       

  Williston           8,739      8,739      8,739      8,739       8,739       8,739

  ***Urban/Suburban                                                            
  Family***                                                                    

  Augusta             6,643      8,643      8,643      6,643       8,643       6,643

  Onsite SRS          2,000      0          0          2,000       0           2,000

  ***Delivery                                                                  
  Family***                                                                    

  Martin              189        189        189        189         189         189

  Onsite SRS          400        0          0          400         0           400

  Allendale           1,600      0          0          1,600       0           1,600

  Barnwell            6,454      8,454      8,454      6,454       8,454       6,454

  ***Outdoors Person                                                           
  Family***                                                                    

  Onsite SRS          1,740      0          0          1,740       0           1,740

  Jackson             6,643      8,643      8,643      6,643       8,643       6,643

  ***Family Near                                                               
  River***                                                                     

  Martin              8,447      8,447      8,447      8,447       8,447       8,447

  ***Migrant Worker                                                            
  Family***                                                                    

  New Ellenton        4,370      4,370      4,370      4,370       4,370       4,370

  **\***During the                                                             
  indicated years                                                              
  (1969-1972 for the                                                           
  Child Born in 1955,                                                          
  and 1978-81 for the                                                          
  Child Born in                                                                
  1964), the children                                                          
  born in 1955 and                                                             
  1964 are classed as                                                          
  teenagers.                                                                   
  ----------------------------------------------------------------------------------------

Table 9‑7 Indoor and Outdoor Fractions for Ground Contamination Pathway

  ------------------------------------------------------------------------------------------------------------------------------
  Member        Location     Outdoor           Indoor     Member                         Location   Outdoor           Indoor
                             Fraction          Fraction                                             Fraction          Fraction
  ------------- ------------ ---------- ------ ---------- ------------------- ---------- ---------- ---------- ------ ----------
  ***Rural                                                ***Urban/Suburban                                           
  Family One***                                           Family***                                                   

  Infant        Girard                  0.15   0.85       Infant                         Augusta    0.14              0.86

  Preschooler   Girard                  0.15   0.85       Preschooler                    Augusta    0.14              0.86

  School Child  Girard                  0.18   0.82       School Child                   Augusta    0.17              0.83

  Teen          Girard                  0.13   0.87       Teen                           Augusta    0.14              0.86

  Teen          Waynesboro              0.29   0.71       Adult Male                     Augusta    0.13              0.87

  Adult Male    Girard                  0.31   0.69       Adult Male                     SRS        0.13              0.87

  Adult Female  Girard                  0.14   0.86       Adult Female                   Augusta    0.13              0.87

  ***Rural                                                ***Family Near                                              
  Family Two***                                           River***                                                    

  Infant        Williston               0.15   0.85       Infant              Martin                0.14              0.86

  Preschooler   Williston               0.15   0.85       Preschooler         Martin                0.14              0.86

  School Child  Williston               0.18   0.82       School Child        Martin                0.18              0.82

  Teen          Williston               0.15   0.85       Teen                Martin                0.15              0.85

  Adult Male    Williston               0.31   0.69       Adult Male          Martin                0.13              0.87

  Adult Female  Williston               0.14   0.86       Adult Female        Martin                0.13              0.87

  ***Delivery                                             ***Outdoor                                                  
  Person                                                  Person***                                                   
  Family***                                                                                                           

  Infant        Martin                  0.45   0.55       Infant              Jackson               0.15              0.85

  Infant        Barnwell                0.14   0.86       Preschooler         Jackson               0.15              0.85

  Preschooler   Martin                  0.45   0.55       School Child        Jackson               0.18              0.82

  Preschooler   Barnwell                0.14   0.86       Teen                Jackson               0.15              0.85

  School Child  Martin                  0.45   0.55       Adult Male          Jackson               0.14              0.86

  School Child  Barnwell                0.18   0.82       Adult Male          SRS                   1.0               0

  Teen          Martin                  0.45   0.55       Adult Female        Jackson               0.14              0.86

  Teen          Barnwell                0.15   0.85       ***Migrant Worker                                           
                                                          Family***                                                   

  Adult Male    Martin                  0.45   0.55       Infant              New                              0.15   0.85
                                                                              Ellenton                                

  Adult Male    Barnwell                0.13   0.87       Preschooler         New                              0.15   0.85
                                                                              Ellenton                                

  Adult Male    SRS                     0.50   0.50       School Child        New                              0.18   0.82
                                                                              Ellenton                                

  Adult Male    Allendale               0.16   0.84       Teen                New                              0.15   0.85
                                                                              Ellenton                                

  Adult Female  Martin                  0.45   0.55       Adult Male          New                              0.31   0.69
                                                                              Ellenton                                

  Adult Female  Barnwell                0.13   0.87       Adult Female        New                              0.14   0.86
                                                                              Ellenton                                
  ------------------------------------------------------------------------------------------------------------------------------

###  Exposure to a Contaminated Shoreline

External exposure from being on the shore of a river or stream is
similar to external exposure from contaminated soil. The principal
differences for this study are: (1) the contamination on the shoreline
results from contaminated sediment deposited there by contaminated
water, rather than from contaminated air; (2) the deposited sediment
geometry is comprised of two relatively narrow strips on either side of
the river or stream; and (3) the time spent at the shoreline is much
less than the time spent on contaminated ground. As with external
exposure from contaminated soil, the concentration of radionuclides in
the narrow strips is assumed to be constant for a given year.

Key variables for determining the intake for exposure to contaminated
sediments on the shoreline are:

-   Concentration of each radionuclide in the sediment at a particular
    shoreline location.

-   Shoreline width factor.

-   Shoreline use daily event frequency (frequency of shoreline use per
    day) at the shoreline location.

-   Duration of each shoreline use (hours per event).

-   Shoreline use annual event frequency (number of days per year the
    shoreline is used).

The approach used to calculate yearly average radionuclide
concentrations in sediment at various shoreline exposure locations is
described in [Chapter 8](../Chapter_08_ready%20for%20CDC%20031405.doc).
The shoreline width factor is taken to be 0.2 for all locations. Because
the source of radiation is comprised of two strips rather than an
infinite plane, the radiation level is only a fraction of the infinite
plane value, which is accounted for by this factor. This is the default
value used in the GENII code, the value recommended by the NRC for river
shorelines (6), and the value used in past environmental analyses for
SRS (7), (8), (9). Variables (3), (4), and (5) multiplied together equal
the total time per year spent on the shoreline; values for these total
times are provided in Table 9-7. Note that only the Delivery Family,
Outdoors Family, and Near-River Family have any shoreline exposure.
Although other scenarios may participate in shoreline activities, the
shorelines are on bodies of water that receive no waterborne releases
from the SRS; in these cases it was assumed that the water and
shorelines were uncontaminated by SRS activities. Thus the shoreline
exposure times for Rural Family One, Rural Family Two, the
Urban/Suburban Family, and the Migrant Worker Family were all assumed to
be zero.

For the remaining receptors, exposure times were determined as follows:

-   All members of the Delivery Person Family split their shoreline use
    equally between Lower Three Runs Creek near Martin and the Savannah
    River at Smith Lake. Shoreline exposure rates are estimated using
    the following factors based on South Carolina recreational patterns
    cited in Hamby 1991 \[pp.6 and 24\](10):

    \- Average number of shoreline usage events/year -- 19.15

    \- Average hours/shoreline usage event -- 4.44

    85 hr/yr is the product of these values.

-   The Outdoors Person Adult Male (and children when they become
    working adults) used the shoreline on the Savannah River downstream
    of SRS; this location represented job-related exposures associated
    with employment onsite at the SRS. This time includes time spent
    fishing and hunting. The exposure level assumes the adult male was
    "on the river" 8 hours/day (40 hours/week) during the summer (13
    weeks)(5). It further assumes that half the time spent "on the
    river" was spent on the shoreline, and the other half was spent on a
    boat. This results in an exposure time of 260 hours/year on the
    shoreline for the adult male.

-   The Family Living Near the River used the shoreline on the Savannah
    River downstream of the SRS; an exposure time of 365 hours a year
    assumed an average of one hour per day shoreline exposure for every
    day of the year

Locations and exposure times for shoreline external exposure are
summarized in Table 9-8.

Table 9‑8 Exposure Times (hours/year) for Shoreline External Exposure
Pathway

+-----------+-------------------------------+--------------------------+
| Scenario  | Shoreline Usage Location      | Exposure Time            |
|           |                               | (hours/year)             |
+===========+===============================+==========================+
| Rural     | Briar Creek near Girard       | 0 (all years and         |
| Family    |                               | individuals)\*           |
| One       |                               |                          |
+-----------+-------------------------------+--------------------------+
| Rural     | Savannah River upstream of    | 0 (all years and         |
| Family    | SRS and farm ponds around     | individuals)\*           |
| Two       | Williston                     |                          |
+-----------+-------------------------------+--------------------------+
| Urban     | Savannah River at Augusta     | 0 (all years and         |
| /Suburban |                               | individuals)\*           |
| Family    |                               |                          |
+-----------+-------------------------------+--------------------------+
| Delivery  | Lower Three Runs Creek (LTRC) | For all years and        |
| Person    | at Martin (50%) and the       | individuals:             |
|           | Savannah River down stream of |                          |
|           | the LTRC confluence (50%).    | 42.5 on LTRC shoreline   |
|           |                               | at Martin                |
|           |                               |                          |
|           |                               | 42.5 on Savannah         |
+-----------+-------------------------------+--------------------------+
| Outdoors  | Savannah River:               | 260 for the adult male   |
| Person    |                               | on the Savannah River    |
|           | Upstream of SRS for the adult | downstream of the SRS;   |
|           | female and children.          | also used for children   |
|           |                               | after they reach age 18. |
|           | Downstream of SRS for the     |                          |
|           | adult male.                   |                          |
+-----------+-------------------------------+--------------------------+
| Family    | Savannah River Downstream of  | 365 (all years and       |
| Living    | SRS for all individuals.      | individuals)             |
| Near the  |                               |                          |
| River     |                               |                          |
+-----------+-------------------------------+--------------------------+
| Migrant   | Savannah River upstream of    | 0 (all years and         |
| Worker    | SRS and farm ponds around New | individuals)\*           |
| Family    | Ellenton                      |                          |
+-----------+-------------------------------+--------------------------+

\*The dose from shoreline external exposure is assumed to be zero,
because the exposure location received no waterborne releases from the
SRS; in these cases it was assumed that the water was uncontaminated by
SRS activities.

### Immersion in Contaminated Water While Swimming

In this study doses from swimming were modeled through two separate but
related exposure pathways: (1) external exposure by immersion in
contaminated water, discussed here, and (2) inadvertent ingestion of
contaminated water, discussed in Section 9.4.

External exposures from immersion in a contaminated body of water are
similar in nature to exposures from immersion in a contaminated plume of
air, as discussed in Section 9.3.1. A significant difference is that
radiation is attenuated more rapidly in water because of its higher
density.

Key variables in determining the exposure for immersion in a
contaminated body of water are:

1\. Concentration of each radionuclide in the water at a location used
for swimming.

2\. Swimming daily event frequency (frequency of swimming per day) at
the particular swimming location.

3\. Duration of each swimming event (hours per event).

4\. Swimming event annual frequency (number of days per year swimming
occurs).

The approach used to calculate annual radionuclide concentrations in
water at two exposure locations is described in [Chapter
8](../Chapter_08_ready%20for%20CDC%20031405.doc). Variables (2), (3),
and (4) multiplied together equal the total time per year spent swimming
and therefore immersed in contaminated water; values for these total
times are provided in Table 9-8.

Note that only the Delivery Family and Near-River Family have any
exposure due to swimming in contaminated water. Although other scenarios
may participate in swimming activities, that swimming was specified to
take place in bodies of water that receive no waterborne releases from
the SRS; for these scenarios it was assumed that the water was
uncontaminated by SRS activities. Thus the swimming exposure times for
Rural Family One, Rural Family Two, the Urban/Suburban Family, the
Outdoors Person Family, and the Migrant Worker Family were all assumed
to be zero.

Consistent with the scenarios described in [Chapter
3](../Chapter_03_ready%20for%20CDC%20031405.doc), swimming locations
were: (1) Lower Three Runs Creek near Martin, SC, for the Delivery
Person Family and (2) the Savannah River downstream of SRS for the
Family Living Near the River. Time spent swimming were based on South
Carolina recreational patterns cited in Hamby 1991 \[p.6 and 24\] (10).
The Hamby values are based on \"Outdoor Recreation Assessment and Policy
Plan 1989,\" in the Georgia Recreation Planning Process, GA Department
of Natural Resources, Atlanta, GA, 1990. Swimming times, not
differentiated by age, represent warm-water fishing activity:

-   Average number of lake swimming events/year -- 8.12

-   Average hours/lake swimming event -- 2.61

This results in an exposure rate of 21.2 hours/year, which is applied to
all individuals in the Delivery Person Family. For the Family Living
Near the River, it was assumed that all members of the family spent one
hour per day during the summer swimming in the river; this is more
consistent with the characterization of this family as "always outdoors
and in contact with the river" (5)

Locations and total time immersed in contaminated water while swimming
summarized in Table 9-9.

Table 9‑9 Exposure Locations and Times (hours/year) for Swimming
External Exposure (Water Immersion) Pathway

  ------------------------------------------------------------------------
  Scenario            Swimming Location            Exposure Time
                                                   (hours/year)
  ------------------- ---------------------------- -----------------------
  Rural Family One    Briar Creek near Girard      0 (all years and
                                                   individuals)\*

  Rural Family Two    farm ponds around Williston  0 (all years and
                                                   individuals)\*

  Urban/Suburban      Savannah River at Augusta    0 (all years and
  Family                                           individuals)\*

  Delivery Person     Lower Three Runs Creek       21.2 (all years and
                      (LTRC) at Martin             individuals)

  Outdoors Person     Savannah River upstream of   0 (all years and
                      SRS                          individuals)\*

  Family Living Near  Savannah River Downstream of 91 (all years and
  the River           SRS                          individuals)

  Migrant Worker      Savannah River upstream of   0 (all years and
  Family              SRS and farm ponds around    individuals)\*
                      New Ellenton                 
  ------------------------------------------------------------------------

\* The dose from swimming external exposure (water immersion) is assumed
to be zero, because the exposure location received no waterborne
releases from the SRS; in these cases it was assumed that the water was
uncontaminated by SRS activities.

### Exposure to Contaminated Water While Boating

External exposure from being in a boat on a contaminated body of water
is similar to external exposure from contaminated soil. The differences
are that: (1) the contaminated water, not soil, is the source of
radiation and (2) the boat, not buildings, partially shields the
receptor from the radiation

Key variables for determining the intake for exposure to contaminated
water while boating are:

1\. Concentration of each radionuclide in the water at a location used
for boating.

2\. Shielding factor for boating exposures.

3\. Boating daily event frequency (frequency of boating per day) at the
particular boating location.

4\. Duration of each boating event (hours per event).

5\. Boating event annual frequency (number of days per year boating
occurs).

The approach used to calculate annual radionuclide concentrations in
water at two exposure locations is described in [Chapter
8](../Chapter_08_ready%20for%20CDC%20031405.doc). The shielding factor
accounts for the shielding from external radiation provided by the
structure and composition of the boat; the shielding factor was assumed
to have a value of 1.0 for all scenarios and receptors; this
conservatively assumes the boat provides no shielding. Variables (3),
(4), and (5) multiplied together equal the total time (in hours) per
year spent boating and therefore exposed to direct radiation from
contaminated water; values for these total times are provided in Table
9-10.

Table 9‑10 Exposure Times (hours/year) and Locations for Boating
External Exposure Pathway

+----------------+-----------------------------+----------------------+
| Scenario       | Boating Exposure Location   | Exposure Time        |
|                |                             | (hours/year)         |
+================+=============================+======================+
| Rural Family   | No boating activity         | 0 (all years and     |
| One            |                             | individuals)         |
+----------------+-----------------------------+----------------------+
| Rural Family   | No boating activity         | 0 (all years and     |
| Two            |                             | individuals)         |
+----------------+-----------------------------+----------------------+
| Urban/Suburban | Savannah River at Augusta   | 0 (all years and     |
| Family         |                             | individuals)\*       |
+----------------+-----------------------------+----------------------+
| Delivery       | Savannah River Downstream   | 96 (all years and    |
| Person         | of SRS.                     | individuals)         |
+----------------+-----------------------------+----------------------+
| Outdoors       | Savannah River Downstream   | 356 for adult male   |
| Person         | of SRS.                     | and children age 18  |
|                |                             | and over;            |
|                |                             |                      |
|                |                             | 96 for adult female  |
|                |                             | and children under   |
|                |                             | age 18.              |
+----------------+-----------------------------+----------------------+
| Family Living  | Savannah River Downstream   | 192 (all years and   |
| Near the River | of SRS.                     | individuals)         |
+----------------+-----------------------------+----------------------+
| Migrant Worker | No boating activity         | 0 (all years and     |
| Family         |                             | individuals)         |
+----------------+-----------------------------+----------------------+

\* The dose from boating external exposure is assumed to be zero,
because the exposure location received no waterborne releases from the
SRS; in this and similar cases it was assumed that the water was
uncontaminated by SRS activities.

The scenarios specified no boating activity for Rural Family One, Rural
Family Two, and the Migrant Worker Family. For the Delivery Person
Family, the Family Living Near the River, and the Outdoors Person
boating occurred on the Savannah River downstream of SRS. Boating times
are estimated using the factors for boating based on South Carolina
recreational patterns cited in Hamby 1991 (10) and shown below in Table
9-11. These values are based on \"Outdoor Recreation Assessment and
Policy Plan 1989,\" in the Georgia Recreation Planning Process, GA
Department of Natural Resources, Atlanta, GA, 1990. The numbers apply to
all age groups and include two categories -- canoeing and
boating/sailing.

Table 9‑11 South Carolina Boating Usage Rates (adapted from Hamby 1991)

  -------------------------------- ----------------- ---------------------
  Boating Usage                    Canoe Trails      Boating / Sailing

  Events / Year (average)          6.13              18.77

  Hours / Event (average)          2.25              4.38

  Hours / Year                     13.8              82.2

  Total                            96 hours/year     
  -------------------------------- ----------------- ---------------------

The total rate (96 hours/year) was applied to all individuals in the
Delivery Person Family. Twice this exposure time was assumed for the
Family Living Near the River, because their contact with the water was
specified as higher than normal. For the Outdoors Person family, all
family members, but the Adult Male, were assumed to have the regional
average exposure time, the same as the Delivery Person Family. However
the Adult Male had both occupational and recreational exposure; the
average recreational exposure of 96 hours/year was added to an
occupational exposure of 260 hours/year for a total of 356 hours/year.
For the Adult Male's occupational exposure the amount of time spent
boating was assumed to be half the time spent "on the river," and the
time spent "on the river" was cited in Lockridge 2002 (5) as 8 hours/day
(i.e., 40 hours/week) during the summer (i.e., 13 weeks) (0.5 x 40 x 13
= 260 hours/year).

## Ingestion Exposure Route

Ingestion exposure pathways modeled in this study include:

-   Ingestion of plants by humans, including:

> Leafy vegetables
>
> Root vegetables
>
> Fruit
>
> Grain

-   Ingestion of animal products by humans, including:

> Beef
>
> Poultry
>
> Milk
>
> Eggs
>
> Fish

-   Inadvertent consumption of contaminated soil

-   Inadvertent consumption of contaminated water while swimming.

As shown in Table 9-1, the all these exposure pathways are associated
only with radionuclide releases to air, with the exception of ingestion
of fish and inadvertent ingestion of water while swimming; these last
two pathways are associated only with radionuclide releases to water.
With the exception of fish, contamination of plants and animals resulted
from the contamination of soil by deposition of airborne radionuclides.
Soil was not considered to be contaminated by deposition of water-borne
radionuclides, because farmers in vicinity of the SRS did not use the
Savannah River and Lower Three Runs Creek for irrigation (as explained
in [Chapter 3](../Chapter_03_ready%20for%20CDC%20031405.doc)). In this
study, ingestion of beef was used to represent consumption of all types
of meat and meat products, except poultry.

### Food-Chain Ingestion Exposures

The general intake equation (9-2) can be simplified for ingestion of
foodstuffs to be:

I = C~f~·U·ED·T (9-3)

Where, I is the intake;

C~f~ is the radionuclide concentration in the contaminated food;

U is the consumption rate of the food, i.e., the contact rate for
ingestion

ED is the exposure duration, set to one year, since this study examines
doses on an annual basis;

> T is a special form of the annual activity factor representing the
> fraction of the food consumed that was produced in the vicinity of SRS
> and therefore was considered contaminated.

The general food intake equation (9-3) was adapted further for this
study to reflect the receptor behaviors specified by the CDC scenarios.
In particular, the scenarios specified the locations from which the
receptors obtained their food. This was an important aspect of the
scenario specifications, since different locations potentially
experienced different contamination levels from SRS releases, because of
differing distances from the sources and the inhomogeneous air
dispersion patterns at the SRS. In general the radionuclide
concentration in the food (C~f~·), the ingestion rate (U), and the
fraction contaminated (T) may all be a function of the location where
the food was produced. A more precise rendering of equation (9-3) is:

I~total~ = ∑I~L~ = C~fL~·U~L~·ED·T~L~ (9-4)

Where all the variables are defined as before, but the index "L" refers
to location and I~total~ represents the total intake of a particular
radionuclide for a particular receptor for a particular food. For
example, as shown in Table 9-176 and Table 9-187 the Outdoors Person
Family consumed as much meat (modeled as beef) as most other scenarios.
A large fraction (75%) of this meat came from the SRS, while the
remainder (25%) came from Jackson. The fraction of contamination of the
meat from Jackson was set to 0.5 to reflect production of meat products
distant from the SRS (e.g., hot dogs, lunch meats, and other processed
meats); the fraction of contamination of meat from the SRS was set to
1.0 to reflect consumption of game taken from the site.

The source location of various terrestrial foods for each scenario is
shown in Table 9-12. In general, both the amount of food consumed from
each source location and the fraction of the food contaminated varies
with the location and type of food. Note that for four scenarios all
foods originate at a single location unique to that scenario: Rural
Family #1, Rural Family #2, Near River Family, and the Migrant Worker
Family.

[Chapter 8](../Chapter_08_ready%20for%20CDC%20031405.doc) describes how
the concentrations in food were calculated. The following subsections
briefly provide the values chosen for consumption rate, U, and fraction
contaminated, T, for the nine types of food considered, as well as the
rationale for these choices.

Table 9‑12 Source Locations for Various Terrestrial Food Types (and Soil
Ingestion) for Each Scenario\*

  ---------------- ------- --------- ------ ------ ------- ------ ------- ------- ------
                   FOOD                                                           
                   TYPE                                                           

  CDC SCENARIO     Beef    Poultry   Milk   Eggs   Leafy   Root   Fruit   Grain   Soil
                                                   Veg.    Veg.                   

  Rural Family #1  G       G         G      G      G       G      G       G       G

  Rural Family #2  W       W         W      W      W       W      W       W       W

  Urban/Suburban   A       A         A/NE   A      A       A      A       A       A

  Delivery Person  B/M     B/M       B/M    B/M    B/M     B/M    B/M     B/M     B/M

  Outdoors Person  J/SRS   J         J      J      J       J      J       J       J

  Near River       M       M         M      M      M       M      M       M       M

  Migrant Worker   NE      NE        NE     NE     NE      NE     NE      NE      NE
  ---------------- ------- --------- ------ ------ ------- ------ ------- ------- ------

\*Key to locations: G -- Girard; W -- Williston; A -- Augusta; NE -- New
Ellenton; B -- Barnwell; M -- Martin; J -- Jackson; SRS -- Onsite SRS.

#### Ingestion of Leafy and Root Vegetables and Fruit

The Exposure Factors Handbook (4) was used to determine consumption
rates of leafy vegetables, root and other vegetables, and fruit. This
reference is based on data from U.S. Department of Agriculture studies,
including the periodic National Food Consumption Surveys (NFCS) and the
Continuing Surveys of Food Intakes by Individuals (CSFII).

Ingestion rates determined for leafy and root vegetables and fruit are
listed in Table 9-13. Exposure factors reflect the assumptions that (1)
half the leafy vegetables, root vegetables, and fruit consumed by the
Delivery Person Family were obtained from the Barnwell area and half
from the Martin area, and (2) the Migrant Worker Family was in the SRS
vicinity for only half of any year.

The fractions of foodstuffs contaminated (adjustment factors) are listed
in Table 9-14. Note that for Rural Families One and Two the values
change after 1959, but that values for all other scenarios are constant
for the entire 39-year study period. The time dependencies of these
values for different scenarios were mandated by the scenario
specifications (5).

Table 9‑13 Ingestion Rates (kg/yr) for Three Produce Categories

<table style="width:100%;">
<colgroup>
<col style="width: 21%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 7%" />
<col style="width: 8%" />
<col style="width: 8%" />
</colgroup>
<thead>
<tr class="header">
<th rowspan="2">Individual</th>
<th colspan="3">All Other Scenarios<sup>‡</sup></th>
<th colspan="3">Delivery Person Family
(Barnwell/Martin)<sup>†</sup></th>
<th colspan="3">Migrant Worker Family</th>
</tr>
<tr class="odd">
<th>LV*</th>
<th>RV*</th>
<th>F*</th>
<th>LV</th>
<th>RV</th>
<th>F</th>
<th>LV</th>
<th>RV</th>
<th>F</th>
</tr>
</thead>
<tbody>
<tr class="odd">
<td><strong>Adult M</strong></td>
<td>16.7</td>
<td>79.2</td>
<td>55.2</td>
<td><p>8.35/</p>
<p>8.35</p></td>
<td><p>39.6/</p>
<p>39.6</p></td>
<td><p>27.6/</p>
<p>27.6</p></td>
<td>8.35</td>
<td>39.6</td>
<td>27.6</td>
</tr>
<tr class="even">
<td><strong>Adult F</strong></td>
<td>16.7</td>
<td>57.2</td>
<td>56.6</td>
<td><p>8.35/</p>
<p>8.35</p></td>
<td><p>28.6/</p>
<p>28.6</p></td>
<td><p>28.3/</p>
<p>28.3</p></td>
<td>8.35</td>
<td>28.6</td>
<td>28.3</td>
</tr>
<tr class="odd">
<td><strong>1955 Child:</strong></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="even">
<td>Infant 1955</td>
<td>1.2</td>
<td>26.6</td>
<td>61.7</td>
<td><p>0.6/</p>
<p>0.6</p></td>
<td><p>13.3/</p>
<p>13.3</p></td>
<td><p>30.85/</p>
<p>30.85</p></td>
<td>0.6</td>
<td>13.3</td>
<td>30.85</td>
</tr>
<tr class="odd">
<td>Preschool 1965-68</td>
<td>4.1</td>
<td>31.1</td>
<td>50.7</td>
<td><p>2.05/</p>
<p>2.05</p></td>
<td><p>15.55/</p>
<p>15.55</p></td>
<td><p>25.35/</p>
<p>25.35</p></td>
<td>2.1</td>
<td>15.55</td>
<td>25.35</td>
</tr>
<tr class="even">
<td>School 1960-66</td>
<td>8.1</td>
<td>41.9</td>
<td>52.0</td>
<td><p>4.05/</p>
<p>4.05</p></td>
<td><p>20.95/</p>
<p>20.95</p></td>
<td><p>26.0/</p>
<p>26.0</p></td>
<td>4.05</td>
<td>20.95</td>
<td>26.0</td>
</tr>
<tr class="odd">
<td>Teen 1967-73</td>
<td>10.6</td>
<td>63.2</td>
<td>49.4</td>
<td><p>5.3/</p>
<p>5.3</p></td>
<td><p>31.6/</p>
<p>31.6</p></td>
<td><p>24.7/</p>
<p>24.7</p></td>
<td>5.3</td>
<td>31.6</td>
<td>24.7</td>
</tr>
<tr class="even">
<td>Adult 1974-92</td>
<td>16.7</td>
<td>79.2</td>
<td>55.2</td>
<td><p>8.35/</p>
<p>8.35</p></td>
<td><p>39.6/</p>
<p>39.6</p></td>
<td><p>27.6/</p>
<p>27.6</p></td>
<td>8.35</td>
<td>39.6</td>
<td>27.6</td>
</tr>
<tr class="odd">
<td><strong>1964 Child:</strong></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="even">
<td>Infant 1964</td>
<td>1.2</td>
<td>26.6</td>
<td>61.7</td>
<td><p>0.6/</p>
<p>0.6</p></td>
<td><p>13.3/</p>
<p>13.3</p></td>
<td><p>30.85/</p>
<p>30.85</p></td>
<td>0.6</td>
<td>13.3</td>
<td>30.85</td>
</tr>
<tr class="odd">
<td>Preschool 1965-68</td>
<td>4.1</td>
<td>31.1</td>
<td>50.7</td>
<td><p>2.05/</p>
<p>2.05</p></td>
<td><p>15.55/</p>
<p>15.55</p></td>
<td><p>25.35/</p>
<p>25.35</p></td>
<td>2.1</td>
<td>15.55</td>
<td>25.35</td>
</tr>
<tr class="even">
<td>School 1969-75</td>
<td>8.1</td>
<td>41.9</td>
<td>52.0</td>
<td><p>4.05/</p>
<p>4.05</p></td>
<td><p>20.95/</p>
<p>20.95</p></td>
<td><p>26.0/</p>
<p>26.0</p></td>
<td>4.1</td>
<td>20.95</td>
<td>26.0</td>
</tr>
<tr class="odd">
<td>Teen 1976-82</td>
<td>10.6</td>
<td>63.2</td>
<td>49.4</td>
<td><p>5.3/</p>
<p>5.3</p></td>
<td><p>31.6/</p>
<p>31.6</p></td>
<td><p>24.7/</p>
<p>24.7</p></td>
<td>5.3</td>
<td>31.6</td>
<td>24.7</td>
</tr>
<tr class="even">
<td>Adult 1983-92</td>
<td>16.7</td>
<td>79.2</td>
<td>55.2</td>
<td><p>8.35/</p>
<p>8.35</p></td>
<td><p>39.6/</p>
<p>39.6</p></td>
<td><p>27.6/</p>
<p>27.6</p></td>
<td>8.4</td>
<td>39.6</td>
<td>27.6</td>
</tr>
<tr class="odd">
<td colspan="10"><p>*LV: Leafy Vegetables; RV: Root Vegetables; F:
Fruit.</p>
<p><strong><sup>†</sup></strong>The Delivery Person Family obtains half
its produce from Martin and half from Barnwell; table entries represent
this portion.</p>
<p><sup>‡</sup>Rural Families One and Two, Urban/Suburban Family,
Outdoors Person Family, Near Water Family</p></td>
</tr>
</tbody>
</table>

Table 9‑14 Ingestion Rates (kg/y) and Fraction Contaminated (Adjustment
Factor) for Leafy Vegetable, Root Vegetable, and Fruit Ingestion
Exposure Pathways

  -----------------------------------------------------------------------
  Individual               Rural Families One And All Other Scenarios\*
                           Two                    
  ------------------------ ---------------------- -----------------------
  **Adult Male:**                                 

  Thru 1959                0.75                   0.50

  1960 & on                0.625                  0.50

  **Adult Female:**                               

  Thru 1959                0.75                   0.50

  1960 & on                0.625                  0.50

  **1955 Child:**                                 

  Thru 1959                0.75                   0.50

  1960 & on                0.625                  0.50

  **1964 Child:**          0.625                  0.50

  ^\*^ Urban/Suburban                             
  Family, Delivery Person                         
  Family, Outdoors Person                         
  Family, Near River                              
  Family, Migrant Worker                          
  Family                                          
  -----------------------------------------------------------------------

#### Ingestion of Grain

For the grain ingestion pathways, consumption rate data from the
Exposure Factors Handbook (3) was used, as shown in Table 9-15. No data
on local consumption was identified. This data was interpreted by
assuming that most grain and grain products consumed by receptors in the
vicinity of the SRS (i.e. breads, pastas, flours, etc.), would originate
outside the local region. However, corn was expected to be consumed as a
vegetable (e.g., corn on the cob). For purposes of modeling radionuclide
uptake, corn is considered a grain rather than a vegetable. The Exposure
Factors Handbook data is presented in terms of g/kg-day of consumption
and was converted into kg/y by using Tables 7-2 and 7-3 from in the same
source to determine mean body mass as a function of age and gender. The
Exposure Factors Handbook also presents consumption rates based on
geographic region; however, differentiation by age and gender was not
given by geographic region and differences between regions were small,
so regional data were not used.

The contaminated fraction for the Migrant Worker Family was set to 0.5
to account for the fact that the family was completely absent from the
SRS vicinity for one-half the year. For all the remaining scenarios, the
contaminated fraction was set equal to 1.0.

Table 9‑15 Ingestion Rate of Corn (kg/y)

  ------------------------ -------------- --------------- ---------------
                           All Other      Delivery Person 
                           Scenarios      Family          

  Individual                              Martin          Barnwell

  **Adult Male**           4.1            2.05            2.05

  **Adult Female**         3.5            1.75            1.75

  1955 Child:                                             

  Infant 1955              1.2            0.6             0.6

  Preschool 1956-59        2.9            1.45            1.45

  School 1960-66           3.9            1.95            1.95

  Teen 1967-73             3.6            1.8             1.8

  Adult 1974-92            4.1            2.05            2.05

  **1964 Child:**                                         

  Infant 1964              1.2            0.6             0.6

  Preschool 1965-68        2.9            1.45            1.45

  School 1969-75           3.9            1.95            1.95

  Teen 1976-82             3.6            1.8             1.8

  Adult 1983-92            4.1            2.05            2.05
  ------------------------ -------------- --------------- ---------------

#### Ingestion of Beef

Beef was used to represent all non-poultry and non-fish meat that was
eaten by the hypothetical receptors. As explained in the White Paper,
"Treatment of Radionuclide Concentrations in Wild Game in Dose
Reconstruction Modeling" (11) beef was used as a surrogate for venison
from locally-hunted deer. The principal source of information on meat
consumption was the Exposure Factors Handbook (4).

Values used to characterize the consumption of beef reflects the
scenario specifications; in particular the scenarios specified that: (1)
the Delivery Person Family ate beef obtained from both the Martin and
Barnwell areas; (2) the Migrant Worker Family is in the SRS vicinity for
only half the year; and (3) three-quarters of the "beef " eaten by the
Outdoors Person Family was venison from deer taken on the SRS site and
one-quarter came from Jackson as farm-raised beef or other meat. Beef
consumption rates are listed for each receptor in Table 9-16.

The fraction of the beef consumed that was considered to be contaminated
(adjustment factor) took into account a number of assumptions that are
discussed and referenced in [Appendix
E](../Appendix_E%20ready%20for%20CDC%20031405.doc). For several
scenarios 50% of beef purchased at local groceries was considered
locally grown and therefore contaminated. The fraction of beef that is
contaminated is listed for each receptor in Table 9-17.

Table 9‑16 Consumption Rate (kg/y) of Beef (Meat)

  --------------- -------------- ---------- ----------- ---------- --------- ----------
  Individual      Rural Families Delivery               Outdoors             Migrant
                  One and Two,   Person                 Person               Worker
                  Urban/         Family                 Family               Family
                  Suburban                                                   
                  Family, Near                                               
                  River Family                                               

                                 Martin     Barn-well   Jackson    SRS       New
                                                                   Onsite    Ellenton

  **Adult Male**  78.1           39.05      39.05       19.52      58.58     39.05

  **Adult         49.7           24.85      24.85       12.42      37.28     24.85
  Female**                                                                   

  1955 Child:                                                                

  Infant 1955     25.2           12.6       12.6        6.3        18.9      12.6

  Preschool       31.4           15.7       15.7        7.85       23.55     15.7
  1956-59                                                                    

  School 1960-66  50.6           25.3       25.3        12.65      37.95     25.3

  Teen 1967-73    75.6           37.8       37.8        18.9       56.7      37.8

  Adult 1974-92   78.1           39.05      39.05       19.52      58.58     39.05

  **1964 Child:**                                                            

  Infant 1964     25.2           12.6       12.6        6.3        18.9      12.6

  Preschool       31.4           15.7       15.7        7.85       23.55     15.7
  1965-68                                                                    

  School 1969-75  50.6           25.3       25.3        12.65      37.95     25.3

  Teen 1976-82    75.6           37.8       37.8        18.9       56.7      37.8

  Adult 1983-92   78.1           39.05      39.05       19.52      58.58     39.05
  --------------- -------------- ---------- ----------- ---------- --------- ----------

Table 9‑17 Fraction of Beef and Poultry that is Contaminated (Adjustment
Factors)

  ------------ ------------------ ---------------- ---------- ---------- ---------- -------- -------- ----------
               SCENARIO                                                                               

               Rural Family One/  Urban-Suburban   Delivery              Outdoors            Near     Migrant
               Two                Family           Person                Person              River    Worker
                                                   Family                Family              Family   Family

  Production   Williston/Girard   Augusta          Martin     Barnwell   Jackson    SRS      Martin   New
  Location →                                                                        Onsite            Ellenton

  **Adult                                                                                             
  Male:**                                                                                             

  1955-1959    0.75               0.5              0.625      0.5        0.5        1.0      0.5      0.5

  1960-1992    0.625              0.5              0.625      0.5        0.5        1.0      0.5      0.5

  **Adult                                                                                             
  Female**:                                                                                           

  1955-1959    0.75               0.5              0.625      0.5        0.5        1.0      0.5      0.5

  1960-1992    0.625              0.5              0.625      0.5        0.5        1.0      0.5      0.5

  **1955                                                                                              
  Child:**                                                                                            

  1955-1959    0.75               0.5              0.625      0.5        0.5        1.0      0.5      0.5

  1960-1992    0.625              0.5              0.625      0.5        0.5        1.0      0.5      0.5

  1964 Child:  0.625              0.5              0.625      0.5        0.5        1.0      0.5      0.5
  ------------ ------------------ ---------------- ---------- ---------- ---------- -------- -------- ----------

#### Ingestion of Poultry

For the poultry ingestion pathway, consumption rates for specific age
and gender categories from the Exposure Factors Handbook \[Table 11-10\]
(4) were adapted to the age and gender categories used in the modeling
by using the same approach as was used for beef consumption. The rates
that result from this adjustment are shown in Table 9-18 for each
scenario. The fraction of poultry that is considered to be contaminated
for each scenario is based on the descriptions provided by the SRSHES
(4) and are the same fractions contaminated as used for beef ingestion.
These fractions contaminated are shown for each scenario in Table 9-17.

Table 9‑18 Ingestion Rate of Poultry (kg/y)

  ------------------ ----------- ---------- ---------- ---------- ----------
                     All Other   Delivery              Outdoors   
                     Scenarios   Person                Person     
                                 Family                Family     

                                 Martin     Barnwell   Onsite SRS Jackson

  **Adult Male**     11.9        11.9       11.9       11.9       11.9

  **Adult Female**   9.1         9.1        9.1        9.1        9.1

  **1955 Child:**                                                 

  Infant 1955        1.5         1.5        1.5        1.5        1.5

  Preschool 1956-59  6.4         6.4        6.4        6.4        6.4

  School 1960-66     8.0         8.0        8.0        8.0        8.0

  Teen 1967-73       11.7        11.7       11.7       11.7       11.7

  Adult 1974-92      11.9        11.9       11.9       11.9       11.9

  **1964 Child:**                                                 

  Infant 1964        1.5         1.5        1.5        1.5        1.5

  Preschool 1965-68  6.4         6.4        6.4        6.4        6.4

  School 1969-75     8.0         8.0        8.0        8.0        8.0

  Teen 1976-82       11.7        11.7       11.7       11.7       11.7

  Adult 1983-92      11.9        11.9       11.9       11.9       11.9
  ------------------ ----------- ---------- ---------- ---------- ----------

#### Ingestion of Milk

For the milk ingestion pathway, consumption rates were adapted from The
Exposure Factors Handbook (4); these milk consumption rates are listed
in Table 9-19. Note that of the milk consumed by the Urban/Suburban
Family, half came from cows in Augusta, GA, and half came from cows in
New Ellenton, SC. Similarly, for the Delivery Person Family the milk
supply was split evenly between Barnwell and Martin. Because the
scenarios specified that all milk was obtained from sources local to
SRS, the fraction contaminated was set to unity for all scenarios.

Table 9‑19 Consumption Rates (kg/y) for Milk

  ----------------- ------------- ------------- ------------- ------------- ------------- -------------
  Individual        Rural                       Urban/                      Delivery      Migrant
                    Families One                Suburban                    Person Family Worker Family
                    and Two,                    Family                                    
                    Outdoors                                                              
                    Person                                                                
                    Family, Near                                                          
                    River Family                                                          

                                                Augusta/New                 Barnwell/     New Ellenton
                                                Ellenton                    Martin        

  **Adult Male**    73.7          36.85/36.85                 36.85/36.85                 36.9

  **Adult Female**  55.5          27.75/27.75                 27.75/27.75                 27.8

  **1955 Child:**                                                                         

  Infant 1955       131.8         65.9/65.9                   65.9/65.9                   65.9

  Preschool 1956-59 130.2         65.1/65.1                   65.1/65.1                   65.1

  School 1960-66    146.5         73.25/73.25                 73.25/73.25                 73.3

  Teen 1967-73      169.5         84.75/84/75                 84.75/84/75                 84.8

  Adult 1974-92     73.7          36.85/36.85                 36.85/36.85                 36.9

  **1964 Child:**                                                                         

  Infant 1964       131.8         65.9/65.9                   65.9/65.9                   65.9

  Preschool 1965-68 130.2         65.1/65.1                   65.1/65.1                   65.1

  School 1969-75    146.5         73.25/73.25                 73.25/73.25                 73.3

  Teen 1976-82      169.5         84.75/84/75                 84.75/84/75                 84.8

  Adult 1983-92     73.7          36.85/36.85                 36.85/36.85                 36.9
  ----------------- ------------- ------------- ------------- ------------- ------------- -------------

#### Ingestion of Eggs

For the egg ingestion pathway, consumption rates were adapted from The
Exposure Factors Handbook (3); these egg consumption rates are listed in
Table 9-20. Note that of the eggs consumed by the Urban/Suburban Family
all came from hens in Augusta, GA, even though some foodstuffs came from
New Ellenton, SC. For the Delivery Person Family the egg supply was
split evenly between Barnwell and Martin. The quantity of eggs consumed
by the Migrant Worker Family was set to one-half the quantity consumed
by other scenarios, since they were absent from the SRS vicinity for
one-half of each year modeled. Because the scenarios specified that all
eggs were obtained from sources local to SRS, the fraction contaminated
was set to unity for all scenarios.

Table 9‑20 Consumption Rates (kg/y) for Eggs

  ----------------- ------------- ------------- ----------- ------------- -------------
  Individual        Rural         Urban/                    Delivery      Migrant
                    Families One  Suburban                  Person Family Worker Family
                    and Two,      Family                                  
                    Outdoors                                              
                    Person                                                
                    Family, Near                                          
                    River Family                                          

                                  Augusta/New               Barnwell/     New Ellenton
                                  Ellenton                  Martin        

  **Adult Male**    13.9          13.9/0        6.95/6.95                 6.95

  **Adult Female**  8.4           8.4/0         4.2/4.2                   4.2

  **1955 Child**:                                                         

  Infant 1955       1.8           1.8/0         0.90/0.90                 0.90

  Preschool 1956-59 7.7           7.7/0         3.85/3.85                 3.85

  School 1960-66    8.0           8.0/0         4.0/4.0                   4.0

  Teen 1967-73      10.8          10.8/0        5.4/5.4                   5.4

  Adult 1974-92     13.9          13.9/0        6.95/6.95                 6.95

  **1964 Child:**                                                         

  Infant 1964       1.8           1.8/0         0.90/0.90                 0.90

  Preschool 1965-68 7.7           7.7/0         3.85/3.85                 3.85

  School 1969-75    8.0           8.0/0         4.0/4.0                   4.0

  Teen 1976-82      10.8          10.8/0        5.4/5.4                   5.4

  Adult 1983-92     13.9          13.9/0        6.95/6.95                 6.95
  ----------------- ------------- ------------- ----------- ------------- -------------

#### Ingestion of Fish

Radiation exposure through the aquatic food consumption pathway was
modeled as occurring entirely from consumption of fish. Freshwater
crustaceans (e.g., crayfish) and mollusks (e.g., fresh water mussel)
that grew in waters contaminated by liquid releases from the SRS were
not considered to be consumed in sufficient quantities to warrant
modeling. Crabs, shrimp, oysters, and clams from estuarine waters were
certainly consumed in significant quantities; however, because the
habitat for these crustaceans and mollusks is located a significant
distance downriver in brackish or salt water, far away from the SRS, the
levels of radiation in those waters and animals, traceable to the SRS
releases, would be quite small. Modeling these small doses was therefore
not included in the study. Several references were consulted to
determine fish consumption rates, including (4), (10), (12), (13), and
(14). None of these studies of fish consumption, however, were local to
South Carolina and Georgia; therefore consumption rates were based on
the Exposure Factors Handbook (3). For the Delivery Person Family, the
source of the catch was assumed to be split evenly between Lower Three
Runs Creek and the Savannah River. The consumption rate for the Migrant
Worker Family reflected their presence in the SRS vicinity for only
one-half of each year. The consumption rates for fish are summarized in
Table 9-21.

Table 9‑21 Ingestion Rate (kg/yr) for Fish

  --------------- -------- ----------- ---------- ---------- ---------- ------------ ------------ ----------
  Scenario:       Rural    Rural       Urban/     Delivery              Outdoors     Family Near  Migrant
                  Family   Family Two  Suburban   Person                Person       the River    Worker
                  One                  Family     Family                Family                    Family

  Location:       Briar    Creeks,     Savannah   Lower      Savannah   Savannah     Savannah     Creeks,
                  Creek    ponds local River near Three Runs River      River        River        ponds of
                           to          Augusta    Creek      (Smith     (various     (various     New
                           Williston                         Lake)      locations)   locations)   Ellenton

  Individual                                                                                      

  **Adult M**     9.9      9.9         9.9        4.95       4.95       9.9          9.9          4.95

  **Adult F**     9.9      9.9         9.9        4.95       4.95       9.9          9.9          4.95

  **Children:**                                                                                   

  Infant          4.2      4.2         4.2        2.1        2.1        4.2          4.2          2.1

  Preschool       4.2      4.2         4.2        2.1        2.1        4.2          4.2          2.1

  School          5.0      5.0         5.0        2.5        2.5        5.0          5.0          2.5

  Teen            4.5      4.5         4.5        2.25       2.25       4.5          4.5          2.25

  Adult           9.9      9.9         9.9        4.95       4.95       9.9          9.9          4.95
  --------------- -------- ----------- ---------- ---------- ---------- ------------ ------------ ----------

All fish consumed by the two Rural Families, the Urban/Suburban Family,
and the Migrant Worker Family were assumed to come from bodies of water
uncontaminated by SRS releases to surface water. However, all fish
consumed by the Delivery Person Family, the Outdoors Person Family, and
the Family Near the River were assumed to come from bodies of water
contaminated by SRS releases to surface water. Therefore the
contaminated fraction (adjustment factor) was set to unity for the
Delivery Person Family, the Outdoors Person Family, and the Near River
Family; all others were set to zero.

### Inadvertent Soil Ingestion

The total mass of contaminated soil consumed over each year (kg/y) was
based on the Exposure Factors Handbook (4). Daily rates of 100
milligrams per day for children, and 50 milligrams per day for adults,
were apportioned among the exposure locations according to the amount of
time that each receptor spent at each location. Note that unlike most
foodstuffs, the consumption rate of soil is higher for children than for
adults. These soil ingestion rates are summarized in Table 9-22.

### Inadvertent water consumption while swimming

The hourly ingestion rate of water, while swimming, was set equal to
0.05 L/hr, which is the EPA default value (see [Appendix
E](../Appendix_E%20ready%20for%20CDC%20031405.doc)). Based on the
scenario specifications, swimming exposures were set to zero for all
receptors except the Delivery Family and the Near River Family, because
only these families swam in water contaminated by liquid releases from
the SRS. The Delivery Person family swam on Lower Three Runs Creek near
Martin, and the Family Near the River swam on the Savannah River
downstream of the site. Swimming times were 21.2 hours/year for the
Delivery Person Family, and 91 hours per year for the Family Near the
River. Hence, the total amount of contaminated water ingested while
swimming was 1.06 L/year for all members of the Delivery Person Family
and 4.6 L/year for all members of the Family Near the River.

Table 9‑22 Soil Ingestion Rates (kg/year) for Each Scenario by Location
of Soil Ingestion; Children's Ingestion Rates are Shown by Age

  ----------- --------------- -------- ------------- ------------ ---------- --------- ---------- ---------- ------------ ----------- ---------- --------- -------- ------- --------- ----------
  Scenario→                   Rural                  Rural Family Urban/               Delivery                                       Outdoors                      Near    Migrant   
                              Family                 Two          Suburban             Person                                         Person                        River   Worker    
                              One                                                                                                                                                     

  Location→                   Girard   Wayne-sboro   Willi-ston   Augusta    Onsite    Martin     Onsite SRS Allen-dale   Barn-well   Onsite SRS Jackson   Martin                     New
                                                                             SRS                                                                                                      Ellenton

  Person      Age                                                                                                                                                                     

  Adult M     All             0.0183   0             0.0183       0.0141     0.00418   0.000693   0.000836   0.00334      0.0135      0.00418    0.0141    0.0183                     0.009125

  Adult F     All             0.0183   0             0.0183       0.0183     0         0.000393   0          0            0.0177      0          0.0183    0.0183                     0.009125

  Children    Infant\         0.0365   0             0.0365       0.0365     0         0.00128               0            0.0352      0          0.0365    0.0365                     0.01825
  Born in     \<1                                                                                                                                                                     
  1955 and                                                                                                                                                                            
  1964                                                                                                                                                                                

              Pre-school\     0.0365   0             0.0365       0.0365     0         0.00128    0          0            0.0352      0          0.0365    0.0365                     0.01825
              1-4                                                                                                                                                                     

              School-child\   0.0365   0             0.0365       0.0365     0         0.00128    0          0            0.0352      0          0.0365    0.0365                     0.01825
              5-11                                                                                                                                                                    

              Teen\           0.0313   0.00525       0.0365       0.0365     0         0.00128    0          0            0.0352      0          0.0365    0.0365                     0.01825
              12-17                                                                                                                                                                   

              Adult M ≥18     0.0183   0             0.0183       0.0141     0.00418   0.00693    0.000836   0.0034       0.0135      0.00418    0.0141    0.0183                     0.009125
  ----------- --------------- -------- ------------- ------------ ---------- --------- ---------- ---------- ------------ ----------- ---------- --------- -------- ------- --------- ----------

## Inhalation Exposure Route

The inhalation exposure route consists of (1) inhalation of air
contaminated directly by releases to the atmosphere from the SRS and (2)
inhalation of radionuclides that have been resuspended from soil after
initial deposition from contaminated air. The general intake equation
(9-2) can be simplified for inhalation to be:

I = C~a~·U·ED·T (9-5)

Where, I is the intake;

> C~a~ is the radionuclide concentration in air resulting either
> directly from releases or from resuspension;
>
> U is the breathing rate (m^3^/h), i.e., the contact rate for
> inhalation;
>
> ED is the exposure duration, set to one year, since this study
> examines doses on an annual basis;
>
> T is the fraction of time spent at a particular location giving rise
> to the specified air concentration of radionuclides.

[Chapter 5](../Chapter_05_Ready%20for%20CDC%20031405.doc) describes how
the concentrations in air resulting directly from atmospheric releases
from the SRS were calculated. [Chapter
8](../Chapter_08_ready%20for%20CDC%20031405.doc) describes how
concentrations in soil were calculated and how concentrations of
radionuclides in air from resuspended soil were calculated. The
following subsections briefly provide the values for chosen for
breathing rate, U, and fraction of time spent at different locations
with contaminated air or soil, T.

### Air Inhalation

Inhalation rates by age were based on data from the Exposure Factors
Handbook (4). Breathing rates in the Exposure Factors Handbook were
averaged over several age intervals to obtain age-interval-weighted
breathing rates for the age groupings used in this dose calculation.
Inhalation rates (units of m^3^ per year) were created for each receptor
at each exposure location by multiplying a constant daily inhalation
rate, appropriate for the age and gender of the receptor, by the number
of days in a year that the receptor was at a particular exposure
location.

For this phase of the dose reconstruction it was not considered
appropriate to refine the calculation by modeling the potential
differences between indoor and outdoor radionuclide concentrations.
Instead indoor concentrations were considered to be equal to outdoor
concentrations, which is likely to be a pessimistic assumption.
Furthermore this may better reflect conditions early in the site
history, when air conditioning and tightly sealed buildings were not as
common as today. Table 9-23 lists the volume of air breathed per year at
various exposure locations for each scenario; these inhalation volumes
are also related to the age and gender of the various receptors.

Table 9‑23 Breathing Rates (m3/y) for the Family Members of Each
Scenario by Location of Exposure; Children's Breathing Rates are Shown
by Age

  ----------- --------------- -------- ------------- ----------- ---------------- -------- ---------- -------- ------------ ---------- ---------- --------- -------- ----------
  Scenario→                   Rural                  Rural Two   Urban/Suburban            Delivery                                    Outdoors             Near     Migrant
                              One                                                          Person                                      Person               River    Worker

  Location →                  Girard   Waynes-boro   Williston   Augusta          Onsite   Martin     Onsite   Allen-dale   Barnwell   Onsite SRS Jackson   Martin   New
                                                                                  SRS                 SRS                                                            Ellenton

  Person      Age\*                                                                                                                                                  

  **Adult M** All             5,548    0             5,548       4,281            1,267    194        253      1,013        4,088      1,267      4,281     5,548    2,774

  Adult F     All             4,125    0             4,125       4,125            0        144        0        0            3,980      0          4,125     4,125    2,062

  **Child**   Infant\         1,643    0             1,643       1,643            0        57         0        0            1,585      0          1,643     1,643    821
  Born in     \<1                                                                                                                                                    
  1955 or                                                                                                                                                            
  1964                                                                                                                                                               

              Pre-school\     2,811    0             2,811       2,811            0        98         0        0            2,712      0          2,811     2,811    1,405
              1-4                                                                                                                                                    

              School-child\   4,380    0             4,380       4,380            0        153        0        0            4,227      0          4,380     4,380    2,190
              5-11                                                                                                                                                   

              Teen\           5,045    848           5,892       5,892            0        206        0        0            5,686      0          5,892     5,892    2,946
              12-17                                                                                                                                                  

              Adult M ≥18     5,548    0             5,548       4,281            1,267    194        253      1,013        4088       1,267      4,281     5,548    2,774
  ----------- --------------- -------- ------------- ----------- ---------------- -------- ---------- -------- ------------ ---------- ---------- --------- -------- ----------

\*Note that the [year]{.underline} the breathing rate is to be applied
may be calculated by summing the age and the birth year of the child.

### Resuspended Soil

The same exposure variables that were used to calculate intake of
radionuclides by breathing air contaminated directly by SRS releases to
the atmosphere were used to calculate intake of radionuclides by
breathing air contaminated by resuspension of contaminated soil. The
only difference is that the air concentration used in equation (9-5) is
the concentration based on resuspended radioactivity. As explained in
[Chapter 8](../Chapter_08_ready%20for%20CDC%20031405.doc), air
concentration from resuspension is related to the soil concentration by
a simple linear factor, the resuspension factor. For this study, higher
values of the resuspension factor (producing higher air concentrations)
were used for rural locations (Girard, New Ellenton, and Williston),
while lower values were used for all other locations, which were assumed
to have urban or suburban characteristics.

## References

1.  GENII SDD. Napier, B.A., et al. GENII Version II Software Design
    Document. PNNL for U.S. Environmental Protection Agency. November
    2002.

2.  Ashley, C., P.C. Padezanin, and C.C. Zeigler. Environmental
    Monitoring at the Savannah River Plant, Annual Report -- 1982. E.I.
    du Pont de Nemours and Company, Aiken, SC. June 1984.

3.  FRG-13. Eckerman, K. F., et al. Cancer Risk Coefficients for
    Environmental Exposure to Radionuclides. Federal Guidance Report No.
    13, EPA 402-R-99-001. Oak Ridge National Laboratory and U.S. EPA
    Office of Radiation and Indoor Air. September 1999

4.  EPA, 1997. US Environmental Protection Agency, Office of Research
    and Development. Exposure Factors Handbook. EPA/600/P-95/002Fa.
    Washington, D.C. 1997.

5.  Lockridge, 2002. Lockridge J. CY 2002 Status Report Scenario Working
    Group \[unpublished\]. South Carolina. Savannah River Site Health
    Effects Site-Specific Advisory Board, Scenario Work Group. September
    6, 2002.

6.  NRC, 1977. Nuclear Regulatory Commission, Regulatory Guide 1.109.
    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 (NRC, Washington, DC).

7.  WSRC, 1991. Savannah River Site Environmental Report for 1990.
    WSRC-IM-91-28. Westinghouse Savannah River Company, Aiken, SC. 1991.

8.  WSRC, 1992. Savannah River Site Environmental Report for 1991.
    Westinghouse Savannah River Company, Aiken, SC. 1992.

9.  WSRC, 1993. Savannah River Site Environmental Report for 1992.
    WSRC-TR-93-075 and -077. Westinghouse Savannah River Company, Aiken,
    SC. 1993.

10. Hamby, 1991. Hamby DM. Land and Water Use Characteristics in the
    Vicinity of the Savannah River Site. WSRC-RP-91-17. Westinghouse
    Savannah River Company, Aiken, SC. March 1, 1991.

11. McDougall, 2003. Treatment of Radionuclide Concentrations in Wild
    Game in Dose Reconstruction Modeling, ATL International,
    Germantown, MD. 2003

12. EPA, 2002. US Environmental Protection Agency, Office of Science and
    Technology. Estimated per capita fish consumption in the United
    States. EPA-821-C-02-003. Washington, D.C.

13. EPA, 1994. US Environmental Protection Agency, Office of Health and
    Environmental Assessment, Exposure Assessment Group. Estimating
    Exposure to Dioxin-Like Compounds, External Review Draft.
    EPA/600/6-88/005Ca. Washington, D.C. June 1994.

14. EPA, 1991. US Environmental Protection Agency, Office of Emergency
    and Remedial Response, Toxics Integration Branch. Risk Assessment
    Guidance for Superfund, Volume I: Human Health Evaluation Manual,
    Supplemental Guidance, "Standard Default Exposure Factors," Interim
    Final. OSWER Directive 9285.6-03, NTIS PB91-921314. Washington, D.C.
    March 25, 1991.

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[^1]: All references to GENII in this chapter refer to version 2 of
    GENII.