PRESTO (Prediction of Radiological Effects Due to Shallow
Trench Operations) is a computer model for evaluating radiation
exposure from contaminated soil layers, including waste disposal,
soil cleanup, agricultural land application, and land reclamation.
The table below allows you to download both the programs and
the user guides for Version 4.2 of PRESTO-EPA-CPG /POP Operation
System. The PRESTO-EPA-CPG/POP Operation System contains a family
of PRESTO multimedia models:
PRESTO-EPA-CPG (Critical Population Group)
PRESTO-EPA-POP (Population)
These documents are continuously being improved and we encourage
you to comment on the effectiveness and applicability of this
operation system.
These models are intended to support the development of EPA's
environmental standards and criteria. The initial models,
published in 1987, were developed for a mainframe computer.
Subsequent versions were modified to operate on a personal computer
in a DOS environment.
PRESTO-EPA-CPG Operation System
Version 2.0 published in 1993
Version 2.1 published in 1996
PRESTO-EPA-POP Operation System
Version 2.1 published in 1995
The current Version 4.2 of the PRESTO-EPA-CPG/POP Operation
System combines these two systems and operates in a Windows
environment. It also incorporates new features, including
the addition of soil cleanup, agricultural land application,
and land reclamation to the waste trench operation scenarios.
The models are designed to calculate the maximum annual committed
effective dose to a critical population group and cumulative
fatal health effects and genetic effects to the general population
in several scenarios:
near surface disposal trench containing low-level radioactive
waste and/or naturally occurring or accelerator produced
radioactive material (NARM)
residual radionuclides remaining in soil layers after cleanup
agricultural land application of technologically enhanced
naturally occurring radioactive materials (TENORM) waste
stripped land reclamation with applied TENORM waste
The models simulate the transport of radionuclides in air,
surface water, and groundwater pathways, and evaluate exposures
through ingestion, inhalation, immersion and external exposure
pathways.
To avoid overly conservative results, EPA employed the following
approaches:
a dynamic approach for the infiltration sub-model;
a multi-phase leaching concept for the release sub-model;
realistic transition flow from vertical transport reach
to horizontal transport reach for the groundwater sub-model;
and
plausible scenario assumptions for the well mechanics sub-model.
Theoretically, a one-dimensional model can produce a significant
amount of error relative to a three dimensional model; however,
the magnitude of this error depends largely on the conditions
of the application. A recent study indicated that under
normal applications, this relative error may range from zero
to 10 percent for the PRESTO-EPA-CPG and virtually zero error
for PRESTO-EPA-POP.
PRESTO-EPA-CPG and PRESTO-EPA-POP have been subjected to extensive
quality assurance and peer reviews:
extensive quality assurance review of the conceptual model,
computational algorithms, computer coding, documentation,
analysis scenario, and calculations results. (Inter System,
Inc. -1983)
expert review of the PRESTO model focused on the conceptual
model, the results of sample analysis, and documentation.
(42 experts from various institutions, including national
labs, academic entities, industry, and international organizations
-1984)
validation of dynamic infiltration sub-model against field
study data collected for the Barnwell, South Carolina low-level
radioactive waste disposal site by the U.S. Geological Survey
(USGS) and the U.S. Nuclear Regulatory Commission (NRC)-1983
Results
Source
Inches/year
PRESTO analyses
13.8-17.7
USGS field data
14-17
NRC field data
14
analysis of the unique nature of the one-dimensional
groundwater transport model, using Hung's correction factor
to compensate the error induced from the diffusion term (published
by "Nuclear and Chemical Waste Management" -1986)
review of several models proposed for use in
regulatory analyses: PRESTO only model recommended for various
types of analyses that supported licensing of low-level radioactive
waste sites (Compacts Host State Technical Coordinating Committee-1989)
validation of the unique one-dimensional groundwater
transport model, including the vertical transport reach, below
contaminated site collection reach, and horizontal transport
reach, against the three-dimensional MODFLOW-SURFACT model.
The relative errors for the peak concentration at the off-site
well between the two models were less than 10 percent, with
a best case reduced to 3 percent. (2000)
extensive test runs and subsequent reviews of
conceptual model, numerical analysis algorithms, computer
coding, and documentation, which resulted in several minor
modifications.(EPA staff-2000)
