# Fate And Transport Analysis Under Act 2 And Chapter

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```					Fate And Transport Analysis
Under Act 2 And Chapter 245
with Quick Domenico
Quick Domenico
Objectives
   Definition of a Model
   What is Fate and Transport Analysis (F&T)
   What data is needed for F&T Analysis
   What is the Quick Domenico Model (QD)
   Key QD Model Inputs
   Calibration of QD
   Regulatory Framework for QD
   Other F&T Tools
Definition of a Model
Models
 Models are conceptual descriptions or
approximations that describe physical
systems using mathematical equations.
 Usefulness of models depends on how
closely the math approximates the real
world.
What is Fate and Transport
Analysis (F&T)?
Fate and Transport Analysis
   Fate
 Simulates the chemical and/or biological

alteration of contaminants as they move with
groundwater through the subsurface
 Sorption or Desorption

 Organic carbon

 Half-life
Fate and Transport Analysis
   Transport
 Simulates the movement of

groundwater through the geologic
media

 Diffusion

 Dispersion
Fate and Transport Analysis
 Advection – mass transport due to the flow
of water in which the mass is dissolved
 Diffusion – chemical mass flux is

proportional to the gradient in concentration
 Dispersion – process of fluid mixing that

causes a zone of mixing to develop between
fluid of one composition that is adjacent to
or being displaced by a fluid with a different
composition
Fate and Transport Analysis

   Determining the direction, rate of movement
(transport) and future concentrations (fate) at
relevant locations and times
   Commonly applied to
 Exposure concentrations at current or
probable future receptors
 During time frames consistent with the
assumed exposure of the receptor
Fate and Transport Analysis
   Most F&T models have simplifying
assumptions
 Direction of flow

 Geometry of the aquifer

 Homogeneous matrix

 Steady state vs pulse flow
Fate and Transport Analysis
   Goal
 To Simulate the contaminant

concentration, which are in
equilibrium with the groundwater flow
system and the geochemical conditions
defined for the model area.
Fate and Transport Analysis
       Some contamination is left behind at many
sites. We need fate and transport analysis to
help assure that those concentrations do not
result in unacceptable risk to current or future
receptors and that an Act 2 standard is
maintained
       We can use concentrations derived from
fate and transport analyses in risk assessments
Fate and Transport Analysis
     Qualitative Data Analysis
   conceptual model and descriptive
treatment of site data

    Quantitative Data Analysis
 mathematical model
 w/ or w/o post-remediation monitoring
What Data is Needed for
F&T Analysis?
Conceptual Site Model
   Conceptual Site Model aids in determining the
modeling approach and which model software
to use
   Good Site Characterization = Good Conceptual
Model
   Thorough Site Characterization – without
proper site characterization it is not possible to
select an appropriate model OR develop a
reliably calibrated model.
Fate & Transport Analysis starts
with a good site characterization
   ID contaminants of concern
   ID Media of Concern
   Concentrations of substances
   Conceptual model – consistent with field data
 Identification of

 Completed pathways

 Exposure routes

 Receptors

 Sources
Must analyze what has not yet
occurred
   To do this consider
 Properties of the contaminants which affect
their ability to move through the given media
 KOC

 Solubility

 Volatility

 Properties of the media that affect transport

 Porosity

 Permeability

 Fraction of Organic Carbon (FOC)
Choosing these properties
involves some uncertainties
   Some ways to minimize uncertainty
   Collecting site data in sufficient quantity and quality
   Choosing an appropriate model that is consistent
with conceptual model and field data
   Performing sensitivity analysis
 Using variable inputs ID the parameters which
are most sensitive to causing changes to the
model outputs
 Then spend more effort (and \$\$) to gather
quality data to provide more correct values for
those sensitive parameters.
   Calibrating the model with actual data inputs
Hydrogeologic Investigation
   Regional and local geology, topography,
surface water bodies
   Geologic cross sections drawn from soil borings
and well logs
   Thickness and horizontal extent of aquifer and
confining units
   Hydrogeologic boundaries – controls the rate
and direction of movement of groundwater
   Hydraulic head analysis – vertical and
horizontal
Hydrogeologic Investigation
 Groundwater recharge distribution –
groundwater injection, pumping, leakage
from surface water or upper aquifers.
 Average linear groundwater velocity –
direction and rate of flow from field data
Hydrogeologic Investigation
of chemical sources OR sinks
 Initial conditions and distribution
(horizontal and vertical) of contaminants
 Identification of down gradient receptors
 Organic carbon content of geologic media
What is the Quick Domenico
Model?
Quick Domenico
   A Microsoft Excel
application of “An
Analytical Model For
Multidimensional
Transport of a
Decaying
Contaminant
Species”, by P.A.
Domenico
Quick Domenico
   What QD is:               What QD is NOT:
 Calculates the            A magic box that

concentration of           tells you all you
contaminants at            want to know
any point and time         about your
source area of             contaminant
KNOWN size and             plume
concentration
Quick Domenico
   What QD is:                  What QD is NOT:
 Use for dissolved
 A model for
organic contaminants
inorganic
whose fate and
transport can be              contaminants
influenced by first           product transport
order decay and
reaction with organic
carbon in soil
Quick Domenico
   What QD is:             What QD is NOT:
 A model for transient
or pulsed
state conditions
groundwater plumes
 Assumes one
 To be used in a multi-
dimensional              directional
groundwater flow         groundwater flow site
 Assumes uniform         For aquifers with

groundwater flow         highly variable flow
Quick Domenico
   What QD is:                  What QD is NOT:
 To be used in                To be used in
unconsolidated (soil)         fractured bedrock!
aquifers with fairly          Unless the fractured
uniform properties            bedrock acts like a
 Can be used for               soil
dissolved organic            If site data shows no
compounds that react          organic carbon or no
in soil or may be             use QD – use a
subject to                    transport model
Quick Domenico
   What QD is:                What QD is NOT:
 To be used in Karstic
 Can be used to
bedrock under any
model “worst
circumstances!
case” conditions
 Does not calculate
 Only models one             concentrations of
contaminant and             daughter products of
not the synergistic         contaminant
effects of multiple         breakdown (PCE to
TCE)
contaminants
Key Model Inputs
Quick Domenico – What YOU
Input
   Time in Days
   Source concentration
   Hydraulic Conductivity
in mg/L
(k) in ft/day
   Ax – Longitudinal
Dispersivity in ft
ft/ft
   Ay – Transverse
   Porosity as a decimal
Dispersivity in ft
fraction
   Az – Vertical
   Soil Bulk Density in
Dispersivity in ft
g/cm3
   Lambda in days-1
   KOC – carbon
   Source Width in ft           partitioning coefficient -
   Source Thickness in ft       unitless
   Fraction organic carbon
as a decimal fraction
Quick Domenico – What QD
Outputs
 Retardation
 Velocity
 Concentration verses Distance
Calibration of QD
Calibration
 The goal of calibrating a model is to
reduce any disparity between the model
simulations and the field data.
 Also improves the accuracy of the model
Calibration
 Vary the values of different
hydrogeologic and geochemical
conditions in the model to match field
observations.
 Calibrate QD by matching the
Dispersivities to field conditions!
 Ax, Ay and Az
Regulatory Framework
Regulatory Framework for Act 2
   Act 2 Regs - 250.204 (f)(5)
 Fate and transport analyses shall include:

 Name, version, description, and author if
a model is used
 The site characterization data used in the
analysis
 Assumptions and justification used

 Documentation of QA/QC in the analysis

 Documentation of results in appropriate
tables and figures
Regulatory Framework for Act 2

   Act 2 Regs - 250.204(g),.312(e),
 …if fate and transport analysis

indicates that the remediation standard
may be exceeded in the future, or, if
the remediation relies on natural
attenuation, a post remediation care
plan shall be documented in the final
report.
Regulatory Framework for Act 2
   Act 2 Regs - 250.308(d) - Groundwater
Equivalency
 uses fate and transport analysis to show that
regulated substances will not migrate from
base of contamination to gw in excess of the
MSC or background within 30 years
 monitor for eight quarters beneath
contaminated soil to show no exceedences of
MSC and no upward trend
 Buffer.xls may be used for soil model
Regulatory Framework for Act 2
   Act 2 Regs - 250.604(a)
 Site-specific soil-to-gw pathway numbers can

be generated using:
 MSCs=MSCgw((Koc*foc)+(θw/ρb))DF

with site-specific values for input parameters
required for foc, θw, ρb and DF.
Regulatory Framework for Act 2

   Act 2 Regs - 250.708(e)
 documentation by fate and transport

analysis that a standard will not be
exceeded in the future is one of the
requirements for terminating post
remediation care
Regulatory Framework for Tanks
   Tanks Regs - 245.309(b)(5)
 Site characterization objective

 Determine, from measurements at the
site, values for input parameters including
hydraulic conductivity, source
table fluctuation and fraction organic
carbon necessary for fate and transport
analysis
Regulatory Framework for Tanks
   Tanks Regs - 245.312(c)(6), 245.313(b)(4)
(Relating to remedial action progress reports and
remedial action completion reports)
   For fate and transport analyses, in addition to
250.204(f)(5)
 An isoconcentration map showing
configuration and concentrations of
contaminants within the plume being
analyzed
 Sufficient monitoring information to show if
the plume is stable, shrinking or expanding
Regulatory Framework for Tanks
   Tanks Regs - 245.312(c)(6), 245.313(b)(4)
 For fate and transport analyses, in addition
to 250.204(f)(5)
 Input parameters for the analysis and the
rationale for their selection
 Figures showing the orientation of the
model or the analysis to the field data
 Comparison and analysis of the model or
mathematical output to the actual field
data
Application To Act 2 Standards
   Background standard

   Models or fate and transport analysis
not usually necessary

   The background standard is attained
by a statistical comparison of data
Application To Act 2 Standards
   Statewide health standard

   Will gw contamination on the property ever
exceed the standard at the property line

   For non-use aquifer, will contamination ever
exceed the used aquifer MSC at 1000 feet
from property line
Application To Act 2 Standards
   Statewide health standard - non-use
aquifer
 Will contamination that has migrated

or may migrate more than 1000 feet
used aquifers at 1000 feet and beyond
in no more than 30 years
Application To Act 2 Standards
   Site-specific standard
   How will an off-site receptor be impacted

   What gw source concentration will protect
off site receptors

   What numeric value at property line will
protect off-site receptors
Application To Act 2 Standards
   Statewide health and site specific standards

 will the plume discharging into surface
water violate surface water quality criteria
 this analysis may involve a groundwater
solute transport model with PENTOXSD
Application To Act 2 Standards
   Qualitative Prediction:

 Soil source removed-no gw impact
 Well characterized plumes at
 All concentrations in plume below SHS
standard
Application To Act 2 Standards
   Quantitative Prediction:

   Computer model often used:
 to predict a concentration value or
range at a future place or time
 to predict the extent of
contamination
Application To Act 2 Standards
   Quantitative - Prediction with continued
data collection
 In some cases such as karst, complex

bedrock settings or where very
accurate predictions are needed, no
model may suffice. Long term
monitoring as post remedial care may
be required to obtain reliable answers.
Other F&T Tools
Fate and Transport Analysis
Tools
   DEP does not specify use of any particular
unsaturated or saturated zone groundwater
transport model.

   PENTOXSD is required for determining
surface water attainment in many cases.
Fate and Transport Analysis
Tools- SOIL and GW
   www.depweb.state.pa.us
 DEP key word – Land Recycling

   Fate and Transport Analysis Tools
 Quick Domenico

 Fatback4

 PENTOXSB

 Buffer1

 Buscheck and Alcantar
Fatback4
 Calculates the source concentration given
the desired receptor concentration and the
location of the receptor
 Based on the same P.A. Domenico equation
as QD, just does it backwards!
   Estimates the average groundwater concentration,
surface water from diffuse groundwater discharges
for determining surface water compliance of Act 2
and tank remediations using PENTOXSD
   Based on the same P.A. Domenico equation as QD
   Answers the question “Does the plume get to the
stream and at what concentration?”
Buffer 1
 Estimates the potential contaminant
concentration entering groundwater
resulting from migration of a contaminant in
vadose soil of a given thickness and with a
given contaminant concentration
 Based on the equations in Chapter
250.308(c)
Buscheck and Alcantar
   Calculates a lambda value for the centerline of a
plume with a continuous source at steady-state
conditions – plots in ln concentration vs distance
   Based on T.E Buscheck and C.M. Alcantar, 1995,
Regression Techniques and Analytical Solutions
to Demonstrate Intrinsic Bioremediation
   Half life = -0.693/(K*V), where K is the
degradation constant and V is the velocity
Fate and Transport Analysis
Tools - PENTOXSD
 Technical Reference Guide for
PENTOXSD (Technical Guidance
391-2000-011). – Now in eLibrary
 See Tom Starosta at tstarosta@state.pa.us
Other Models
   3DFEMFAT                MOCDENSE
   AQUA3D                  MODFLOW
   AT123D                  MODFLOW SURFACT
   BIOF&T 2-D/3-D          MODFLOWT
   Chemflow                MODFLOW win32
   ChemFlux                MODPATH
   FEFLOW                  MOFAT
   FLONET/TRANS            MS-VMS
   FLOWPATH                MT3D
   GFLOW                   PEST
   GMS                     PESTAN
   Groundwater Vistas      Processing Modflow (PMWIN)
   HST3D                   POLLUTE
   MicroFEM                PRINCE
   MOC                     Etc…………………
Other Models
   California EPA – LA Regional Water Quality
Control Board
   www.swrcb.ca.gov/rwqcb4/html/programs/ust/underground.ht
ml

   Models for Non-steady State Contaminant
Transport in Groundwater – Continuous Source
and Instantaneous/One-time Release
   Model for Steady State Contaminant Transport
in Groundwater
Objectives
   Definition of a Model
   What is Fate and Transport Analysis (F&T)
   What data is needed for F&T Analysis
   What is the Quick Domenico Model (QD)
   Key QD Model Inputs
   Calibration of QD
   Regulatory Framework for QD
   Other F&T Tools

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