DNAPL Source Zone Management Approaches January 8, 2015 SERDP - - PowerPoint PPT Presentation

SERDP & ESTCP Webinar Series

DNAPL Source Zone Management Approaches

January 8, 2015

SERDP & ESTCP Webinar Series

Welcome and Introductions

Rula Deeb, Ph.D. Webinar Coordinator

Webinar Agenda

• Webinar Overview and ReadyTalk Instructions
• Dr. Rula Deeb, Geosyntec

(5 minutes)

• Overview of SERDP and ESTCP, and webinar series goals
• Dr. Andrea Leeson, SERDP and ESTCP

(5 minutes)

• Assessing Source Zone Natural Attenuation at Chlorinated

Solvent Spill Sites

• Dr. Paul Johnson, ASU

(30 minutes + Q&A)

• Reconstructing Source Zone Histories Using High Resolution

Coring To Improve Monitored Natural Attenuation

• Dr. Chuck Newell, GSI

(30minutes + Q&A)

• Final Q&A session

5

SERDP & ESTCP Webinar Series (#6)

How to Ask Questions

6

Type and send questions at any time using the Q&A panel

SERDP & ESTCP Webinar Series (#6)

SERDP & ESTCP Webinar Series

SERDP and ESTCP Overview

Andrea Leeson, Ph.D.

Environmental Restoration Program Manager

SERDP

• Strategic Environmental Research and

Development Program

• Established by Congress in FY 1991
• DoD, DOE and EPA partnership
• SERDP is a requirements driven program

which identifies high-priority environmental science and technology investment

• pportunities that address DoD requirements
• Advanced technology development to address

near term needs

• Fundamental research to impact real world

environmental management

8

SERDP & ESTCP Webinar Series (#6)

ESTCP

• Environmental Security Technology

Certification Program

• Demonstrate innovative cost-effective

environmental and energy technologies

• Capitalize on past investments
• Transition technology out of the lab
• Promote implementation
• Facilitate regulatory acceptance

9

SERDP & ESTCP Webinar Series (#6)

Program Areas

• 1. Energy and Water
• 2. Environmental Restoration
• 3. Munitions Response
• 4. Resource Conservation and

Climate Change

• 5. Weapons Systems and

Platforms

10

SERDP & ESTCP Webinar Series (#6)

Environmental Restoration

• Major focus areas
• Contaminated groundwater
• Contaminants on ranges
• Contaminated sediments
• Wastewater treatment
• Risk assessment

SERDP & ESTCP Webinar Series (#6)

11

SERDP and ESTCP Webinar Series

DATE WEBINARS AND PRESENTERS January 22, 2015 Bio-Based Methodologies for the Production of Environmentally Sustainable Materials

• Dr. Andrew Guenthner (Air Force Research Laboratory, Aerospace Systems

Directorate)

• Dr. Benjamin Harvey (Naval Air Warfare Center, Weapons Division)
• Dr. John La Scala (U.S. Army Research Laboratory)

February 5, 2015 Acoustic Methods for Underwater Munitions

• Dr. Joseph Bucaro (Naval Research Laboratory)
• Dr. Kevin Williams (APL University of Washington)

February 19, 2015 Solar Technologies March 5, 2015 Lead Free Electronics

• Dr. Peter Borgesen (Binghamton University, The State University of New York
• Dr. Stephan Meschter (BAE Systems)

SERDP & ESTCP Webinar Series (#6)

12

SERDP & ESTCP Webinar Series http://serdp-estcp.org/Tools-and- Training/Webinar-Series

SERDP & ESTCP Webinar Series Assessing Source Zone Natural Attenuation at Chlorinated Solvent Spill Sites

• Dr. Paul Johnson

ASU

SERDP & ESTCP Webinar Series Source Zone Natural Attenuation (SZNA) at Chlorinated Aliphatic Hydrocarbon Spill Sites

ESTCP Project ER-200705

Ryan Ekre and Paul C. Johnson Ira A. Fulton Schools of Engineering, Arizona State University

w/ B. Rittmann, R. Krajmalnik-Brown, R. Hinchee, and P. Lundegard field sampling help from B. Cavanagh, P. Dahlen, S. Wilson; and site support from K. Gorder, M. Jensen and G. Wright (Hill AFB); M. Singletary and

• T. Curtin (NAS Jacksonville); M. Singletary and C. Cook (Parris Island MCRD)

ESTCP ER-200705 Overview

Objective: Demonstrate protocol for documenting SZNA and measuring SZNA rates (aka “source zone natural depletion”) Why?: SZNA is a base case against which other treatment options are benchmarked in feasibility assessment SZNA is likely the last and perhaps longest-term treatment train step at many sites Consistency and credibility in approach and documentation are important for acceptability Products: Protocol for CAH sites (e.g., PCE, TCE), with illustrated application using multi-year data collected from 3 sites

Source Zone Treatment Options

Source zone Natural attenuation Enhanced Bioremediation Physical/Chemical Treatment (SVE, IAS, ISCO, etc.) Thermal Treatment

16

SZNA Paradigm Background

SZNA assessment approach for petroleum sites* was adopted by ITRC (2009)

 Data-driven, with data gathering and reduction keyed to specific questions of interest  Complementary to guidance for monitored natural attenuation of groundwater plumes  Complementary to DoD-sponsored calculation tools developed by Chapelle et

• al. (2003) and Groundwater Services, Inc.

(GSI)

* Based on approach developed by Lenski (2004), Liu (2005), Lundegard et al. (2006) and Johnson et al. (2006)

17

Common SZNA-Related Questions

• Is SZNA occurring?
• What is the current SZNA

mass loss rate?

• What processes are

contributing to SZNA

• Are the SZNA processes

sustainable?

• At what point in the future

will groundwater quality and other site management goals be met?

18

SZNA data gathering and reduction are grouped by their usage

General SZNA Protocol Overview

Data and Analyses Questions Answered Data Needs Group 1 Is SZNA

• ccurring?

Typical site characterization data Group 2 What is the SZNA mass loss rate? Source geometry (L, W, D), groundwater transect, vertical vapor profiles, hydraulic conductivity, effective diffusion coefficients Group 3 Future implications – sustainability?, mass loss rate?, plume features? Source zone architecture; limiting reactant supply 19

Note: not important to know loss mechanism details when you assess the mass exchange across the boundaries

Determining SZNA Mass Loss Rate

From Ekre et al. (2014)

20

Group 2 Data Collection

[Cross-section View]

From Ekre et al. (2014)

21

Group 2 Data Collection

[Plan View]

From Ekre et al. (2014)

22

Sample Group 2 Data

[Cross-section View; Dissolved Concentrations and K values]

From Ekre et al. (2014)

23

Group II Data Reduction

[mass loss carried by groundwater flow through down-gradient boundary]

Step 1: Add up all concentrations to an equivalent parent (PCE or TCE) concentration Ceq Step 2: Enter data into GSI Mass Flux Toolkit

(Ceq, K, depth, position)

Step 3: Calculate mass loss rate Step 4: Identify most critical sampling locations for future sampling events

(use sensitivity analysis)

adjustment factor: [mg- parent/mg-chemical]; accounts for Cl- loss http://gsi-net.com/software/free-software/mass-flux-toolkit.html measured concentration [mg/L]

24

Plan View

29 170 65 31 46 270 89 66 24 44 86 33 60 550 VP10 VP11 VP12 VP13 VP14 VP15 VP16 VP17 VP18 VP19 VP20 VP21 VP22 VP23 VP24

(ft) (ft)

measured effective diffusion coefficient

(Johnson et al. 1998)

Upward diffusive transport from source zone through grid block n

Group II Data Reduction

[mass loss carried by vapor diffusion across upper boundary] measured vapor concentration change with depth 25

Demonstration Sites

Location Chemicals Present Geology Sampling Interval

NAS Jacksonville Bldg 106 Former Dry Cleaners PCE,DCE,DCA, VC Sand/Silt with Clay layers 10 – 60 ft bgs Parris Island MCRD Former Dry Cleaners PCE,DCE,VC, LNAPL Sand/Silt; CU ~18 ft bgs 5 – 18 ft bgs Hill AFB Little Mountain Test Annex Sludge Drying Beds PCE,TCE,TCA, DCA,VC and unknowns Fractured Rock: phylite, slate, greenstone 80 – 320 ft bgs

Hill AFB Paris Island NAS Jacksonville 26

Site Background

• Former dry cleaner

site

• PCE Spill
• Depth-to-water ~4-6 ft
• Aquitard ~60 ft bgs
• 10 ft-thick clay layer

at ~16-18 ft bgs

• Upgradient

contamination

• Asphalt parking lot

? ?

0.5 ft 6 ± 1 ft 16 - 18 ft 23 - 25 ft 60 ft

Demonstration Site 1: NAS Jacksonville

27

Demonstration Site 1: NAS Jacksonville

28

100ft

Demonstration Site 1: Transects Evolution

Event 2

• Extra lateral

samples

• Adjusted depths

to increase accuracy

Event 3

• Extra up-

gradient samples

• Adjusted up-

gradient depths

Event 4

• Increased

resolution in core

• Offset vertical

locations

Event 1

• Based on

existing site conceptual model 29

Demonstration Site 1: Transects Evolution

Event 1 Sampling Transect Results Transect sampling provides valuable insight to source zone structure Event 4 Sampling Transect Results GSI Mass Flux Toolkit used to identify critical sampling locations

30

Demonstration Site 1: Transects

Event 4 Mass Flux Distribution [kg/m2-y]

90% of mass discharge occurred through about 20% of plume cross-section

(similar to Mackay et al. (2012), Li et al. (2007), Guilbeault et al. (2005), and others)

31

Demonstration Site 1: Vapor Sampling

Similar iterative evolution of vapor sampling plan from 1st to 4th events Again, majority

• f vapor mass

discharge

• ccurred

through about 20% of the area

Emission (kg/m2-y) Event 4 Former building foundation removed after Event 1

32

Demonstration Site 1: SZNA Rates

SZNA mass loss per year carried by groundwater flow as calculated by different interpolation routines in the Mass Flux Toolkit 2.7 kg/y from groundwater discharge + 0.8 kg/y from vapor discharge calculations = 3.5 kg/y total loss rate

Results for 4th sampling event

33

Demonstration Sites: SZNA Rates w/ Time

Foundation removed No-purge sampling

Not much change in rates with time over 2 – 3 years Results relatively insensitive to changes in sampling plans 34

(ITRC 2010)

Key Observations: 1) At many sites, groundwater flow-related mass loss will be most significant contribution to the SZNA rate 2) At the demo sites, about 90% of the mass loss rate

• ccurred through about

20% of the transect area

SZNA Sampling Plan Designs

Are there practicable sampling plan guidelines that lead to confident estimates of SZNA rates?

35

SZNA Sampling Plan Design Guidelines

Approach: 1) Use high-density data sets from demo sites 2) Create alternate lower- density sampling schemes using heuristic guidelines 3) Calculate SZNA rates from the lower density sampling schemes and compare with result of highest density sampling

±50%

36

SZNA Sampling Plan Design Guidelines

Suggested Approach: 1) Collect a soil core to visually identify distinct layers 2) Coarse sampling with onsite chemical analysis to quickly determine plume width (e.g., 100-ft

horizontal and 25-ft vertical spacings;

• ne sample per major unit vertically)

3) Re-sample plume at higher density:

• Lateral spacing = plume width/6
• Vertical spacing = plume thickness/6

(<25 ft)

• Higher resolution in plume core where

mass flux is highest (<10 ft spacing)

• At least one sample per distinct unit

37

ESTCP ER-200705 Outcomes

Products:

• Illustrated guidance for consistent

assessment of SZNA at CAH sites

• Data-driven approach with relatively

simple data analysis

• Results from 3 demo sites x 4 events

each over 2+ years

• Consistent results with time despite

uncertainties inherent to data collection

• Lessons-learned from demo sites ->

guidance for sampling at other sites

Free download at http://onlinelibrary.wiley.com/ doi/10.1111/gwmr.12049/pdf

38

SERDP & ESTCP Webinar Series

https://www.serdp-estcp.org/News-and- Events/Blog/DNAPL-Source-Zone-Natural- Attenuation http://onlinelibrary.wiley.com/doi/10.1111/gwmr.1 2049/pdf

paul.c.johnson@asu.edu; 480-965-9115

SERDP & ESTCP Webinar Series

Q&A Session 1

40

SERDP & ESTCP Webinar Series Reconstructing Source Zone Histories Using High Resolution Coring to Improve Monitored Natural Attenuation

• Dr. Chuck Newell

GSI Environmental

SERDP & ESTCP Webinar Series

Reconstructing Source Zone Histories Using High Resolution Coring To Improve Monitored Natural Attenuation

ESTCP Project ER-201032 Charles Newell, GSI Environmental Inc.

SERDP & ESTCP Webinar Series

Project Team

Dave Adamson, Chuck Newell GSI Environmental Inc. Beth Parker, University of Guelph Steven Chapman, University of Guelph

Project PIs Team Members

Shahla Farhat (GSI) Phil DeBlanc (GSI) Nick Mahler (GSI) Poonam Kulkarni (GSI) Mike Singletary (NAVFAC) Stone Environmental Inc. T

• m Sale, CSU

44

Project Goals

• Our idea is the knowledge of the past can

be very helpful in managing a contaminated site

• This ESTCP project developed a field

methodology and software tool to reconstruct groundwater concentrations since the release started

• We applied this at two sites and matched

site data, and got insights on historical SZNA

45

Idea #1: Most sites are old sites with a murky, mysterious past

Life is good at Starfort Collectibles until the owners, Caitlin and Trevor Fulmer, acquire a beautiful statuette with a murky past. Shortly thereafter, mysterious hauntings wreak havoc on the couple when a ghost in the attic threatens retribution.

46

Rough Timeline of Our Sites

Releases: 1960s–1970s Sampling: 1980s–1990s

McGuire et al., 2004: Historical and Retrospective Survey of MNA

47

This can make MNA a tough sell…

• GW concentration from wells

located in highly transmissive zone

• Short-term temporal record

PLAN VIEW

GW samples only

SOURCE PLUME

Groundwater data only goes back a few years Noise in these data makes trend calcs difficult What happened before MW-1?

Problem:

Available Data

MW-1

Conc. Time of Release

t

Projecting future trends: High degree of uncertainty Concentration Limited temporal data: No way to estimate source history Time of Release

?

MW-1

48

48

But what if you could fill in the gap?

• Soil concentration from depth-

discrete samples collected from soil cores (diffusion profile)

• GW samples for comparison

Better Conceptual Site Model Better decision making The Thick Blue Line would be really neat to have

Benefit:

Available Data

PLAN VIEW

Soil & GW samples

PLUME SOURCE

t

C

• n

c . Time of Release

Concentration Time of Release would your confidence in MNA as a remedy increase? What if you knew the past looked like this…

49

Idea #2: Growing Acceptance of Source Zone MNA

50

500 ft

Modified from figure provided by B. Parker. Source of Data: Chapman and Parker, 2005

3000 kg TCE present in low-perm zone!

Sourc e Zone Groundwater Flow

Transect 1

N

Show me how it works..

• 3
• 2
• 1

1 2 3 4 20 40 60 80 TCE (mg/L) Distance (m from Interface)

Aquifer Aquitard

Aquifer Aquitard

Chapman and Parker, 2005

High Resolution Sampling

52

Diffusion Signals for Different Sources

Soil profile reflects style of source loading over time Process: Transmissive Zone Low K Zone

Mass transport may be dominated by diffusion

GW flow

Diffusion into/out of low k zone based on concentration gradient

53

Transmissive Zone Low K Zone

Mass transport may be dominated by diffusion Diffusion into/out of low k zone based on concentration gradient

CONSTANT SOURCE

t = 20 yr

54

Diffusion Signals for Different Sources

Soil profile reflects style of source loading over time Process:

GW flow

Transmissive Zone Low K Zone

Mass transport may be dominated by diffusion Diffusion into/out of low k zone based on concentration gradient

CONSTANT SOURCE SOURCE REMOVAL

t = 20 yr t = 25 yr

55

Diffusion Signals for Different Sources

Soil profile reflects style of source loading over time Process:

GW flow

ESTCP Source Attenuation Tool

Using Matrix Diffusion Data to Estimate Source Histories Version 1.0 1962 (yyyy) Site Location and I.D.:

• 1. HYDROGEOLOGY

Type of Material in Low-k Zone Total Porosity n 0.38 (-) Transport Type Hydraulic Conductivity K 2.50E-06 Vertical Hydraulic Gradient i 0.10 (-)

• 2. TRANSPORT

Key Constituent Diffused in Low-k Zone

Molecular Diffusion Coefficient in Free Water D o 8.20E-10 Low-k Zone Apparent Tortuosity Factor Exponent p 1.33 (-) Bulk Density of Low-k Zone ρ b 1.50 (g/mL) Distribution Coefficient K d (L/kg) Calculated R

• r

2.10 Fraction Organic Carbon in Low-k Zone f oc 0.0018 (-) Organic Carbon Partitioning Coefficient K oc 155.00 (L/kg) Constituent Half-Life in Low-k Zone λ 1000

• 3. GENERAL

Year Core Sample Collected from Low-k Zone t 1 2011 (yyyy) RMS Error 2.3 mg/L Relative Error 2.4 mg/L Enter Best Guess for Concentration in Year 1962 Co 71 (mg/L) (If unknown, assume 10% of plume phase solubility.)฀

• 4. HIGH RESOLUTION CORE DATA*

Units for Depth Depth into Low-k Zone (ft) Soil Concentration (mg/kg) 1 0.50 28.96 2 1.00 25.07 3 1.50 18.12 4 1.70 18.46 5 2.00 10.73

• 5. CHECK DATA (OPTIONAL)

Any Town, USA Clay PCE Step 4: To get some general rules on what you need to change to match observed data, click here ---> 0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 2006 2001 1996 1991 1987 1982 1977 1972 1967 1962 Concentration at Transmissive Zone/Low-k Zone Interface (mg/L) Year View All Soil Data Import Soil Data

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

Depth into Low-k Zone (ft) Concentration (mg/L) New Site/Clear Data Paste Example

HELP

Enter your best estimate for the year the original release occurred (e.g., 1971). Step 1: Step 3: Adjust the concentrations in the histogram manually, using up/down buttons, to try to get the dark black line (the model prediction) to match the actual data (orage dots). Use RMS and Relative Error as guidelines for better/worse matches. Step 5: When you get a good match, use the time vs source concentration graph in your MNA report.

• 6. MATCH DATA

Step 2: Select a general first-round concentration vs. time pattern. You will start with this pattern and then modify the source history in Step 4 to match the high-resolution sampling data. if uncertain, start with "Exonential Decay." Linear Decay

• Exp. Decay

Constant Source

? ?

PRINT Check Input Data Log Linear Uncertainty Analysis

Computer Model for Evaluating the Signal

56

ESTCP Source Attenuation Tool

Using Matrix Diffusion Data to Estimate Source Histories Version 1.0 1962 (yyyy) Site Location and I.D.:

• 1. HYDROGEOLOGY

Type of Material in Low-k Zone Total Porosity n 0.38 (-) Transport Type Hydraulic Conductivity K 2.50E-06 Vertical Hydraulic Gradient i 0.10 (-)

• 2. TRANSPORT

Key Constituent Diffused in Low-k Zone

Molecular Diffusion Coefficient in Free Water D o 8.20E-10 Low-k Zone Apparent Tortuosity Factor Exponent p 1.33 (-) Bulk Density of Low-k Zone ρ b 1.50 (g/mL) Distribution Coefficient K d (L/kg) Calculated R

• r

2.10 Fraction Organic Carbon in Low-k Zone f oc 0.0018 (-) Organic Carbon Partitioning Coefficient K oc 155.00 (L/kg) Constituent Half-Life in Low-k Zone λ 1000

• 3. GENERAL

Year Core Sample Collected from Low-k Zone t 1 2011 (yyyy) RMS Error 2.3 mg/L Relative Error 2.4 mg/L Enter Best Guess for Concentration in Year 1962 Co 71 (mg/L) (If unknown, assume 10% of plume phase solubility.)฀

• 4. HIGH RESOLUTION CORE DATA*

Units for Depth Depth into Low-k Zone (ft) Soil Concentration (mg/kg) 1 0.50 28.96 2 1.00 25.07 3 1.50 18.12 4 1.70 18.46 5 2.00 10.73

• 5. CHECK DATA (OPTIONAL)

Any Town, USA Clay PCE Step 4: To get some general rules on what you need to change to match observed data, click here ---> 0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 2006 2001 1996 1991 1987 1982 1977 1972 1967 1962 Concentration at Transmissive Zone/Low-k Zone Interface (mg/L) Year View All Soil Data Import Soil Data

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

Depth into Low-k Zone (ft) Concentration (mg/L) New Site/Clear Data Paste Example

HELP

Enter your best estimate for the year the original release occurred (e.g., 1971). Step 1: Step 3: Adjust the concentrations in the histogram manually, using up/down buttons, to try to get the dark black line (the model prediction) to match the actual data (orage dots). Use RMS and Relative Error as guidelines for better/worse matches. Step 5: When you get a good match, use the time vs source concentration graph in your MNA report.

• 6. MATCH DATA

Step 2: Select a general first-round concentration vs. time pattern. You will start with this pattern and then modify the source history in Step 4 to match the high-resolution sampling data. if uncertain, start with "Exonential Decay." Linear Decay

• Exp. Decay

Constant Source

? ?

PRINT Check Input Data Log Linear Uncertainty Analysis

Hydrogeologic parameter values (porosity, soil density, COC, foc, half-life, estimate of release date, effective diffusion coefficient) High-res CVOC data from soil core in low k zone

LEFT side is data INPUT screen

Enter the data…

57

ESTCP Source Attenuation Tool

Using Matrix Diffusion Data to Estimate Source Histories Version 1.0 1962 (yyyy) Site Location and I.D.:

• 1. HYDROGEOLOGY

Type of Material in Low-k Zone Total Porosity n 0.38 (-) Transport Type Hydraulic Conductivity K 2.50E-06 Vertical Hydraulic Gradient i 0.10 (-)

• 2. TRANSPORT

Key Constituent Diffused in Low-k Zone

Molecular Diffusion Coefficient in Free Water D o 8.20E-10 Low-k Zone Apparent Tortuosity Factor Exponent p 1.33 (-) Bulk Density of Low-k Zone ρ b 1.50 (g/mL) Distribution Coefficient K d (L/kg) Calculated R

• r

2.10 Fraction Organic Carbon in Low-k Zone f oc 0.0018 (-) Organic Carbon Partitioning Coefficient K oc 155.00 (L/kg) Constituent Half-Life in Low-k Zone λ 1000

• 3. GENERAL

Year Core Sample Collected from Low-k Zone t 1 2011 (yyyy) RMS Error 2.3 mg/L Relative Error 2.4 mg/L Enter Best Guess for Concentration in Year 1962 Co 71 (mg/L) (If unknown, assume 10% of plume phase solubility.)฀

• 4. HIGH RESOLUTION CORE DATA*

Units for Depth Depth into Low-k Zone (ft) Soil Concentration (mg/kg) 1 0.50 28.96 2 1.00 25.07 3 1.50 18.12 4 1.70 18.46 5 2.00 10.73

• 5. CHECK DATA (OPTIONAL)

Any Town, USA Clay PCE Step 4: To get some general rules on what you need to change to match observed data, click here ---> 0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 2006 2001 1996 1991 1987 1982 1977 1972 1967 1962 Concentration at Transmissive Zone/Low-k Zone Interface (mg/L) Year View All Soil Data Import Soil Data

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

Depth into Low-k Zone (ft) Concentration (mg/L) New Site/Clear Data Paste Example

HELP

Enter your best estimate for the year the original release occurred (e.g., 1971). Step 1: Step 3: Adjust the concentrations in the histogram manually, using up/down buttons, to try to get the dark black line (the model prediction) to match the actual data (orage dots). Use RMS and Relative Error as guidelines for better/worse matches. Step 5: When you get a good match, use the time vs source concentration graph in your MNA report.

• 6. MATCH DATA

Step 2: Select a general first-round concentration vs. time pattern. You will start with this pattern and then modify the source history in Step 4 to match the high-resolution sampling data. if uncertain, start with "Exonential Decay." Linear Decay

• Exp. Decay

Constant Source

? ?

PRINT Check Input Data Log Linear Uncertainty Analysis

SOURCE HISTORY ESTIMATE (C vs. t in overlying high k aquifer) ADJUST source history until good match w/ high-res CVOC data from soil core in low-k zone is achieved

RIGHT side is data OUTPUT screen

You adjust buttons to match the soil core data

58

Groundwater Flow Direction

Less evidence for transformation along plume flowpath; Significant % of mass associated with clay; Limited spatial extent of chlorinated ethanes

Case Study: Site #1

Soil VOC Results Along Plume Flowpath

59

Preliminary – Analysis May Change

CORE DATA SOURCE HISTORY

30.0 28.0 26.0 24.0 12.0 3.0 1.0 1.0 1.0 1.0

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 2007 2003 1999 1995 1991 1987 1983 1979 1975 1971 Concentration at Transmissive Zone/Low-k Zone Interface (mg/L)

0.0 1.0 2.0 3.0 4.0 5.0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

Depth into Low-k Zone (ft) Concentration (mg/L)

Median RPD = 20% RMS Error = 1.2 mg/L

Excavation “About 1990” SVE in 1998 TCE Only

30 28 26 24 12 3 1 1 1 1

1971 1975 1979 1983 1987 1991 1995 1999 2003 2007

TCE (mg/L):

Year

Site #1: Solvent Building

60

0.0 1.0 2.0 3.0 4.0 5.0 5 10 15 20 25 30

Depth into Low-k Zone (ft) Concentration (mg/L) 160.0 156.0 152.0 148.0 115.0 29.0 16.5 16.0 15.5 15.0

0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 160.0 180.0 2007 2003 1999 1995 1991 1987 1983 1979 1975 1971 Concentration at Transmissive Zone/Low-k Zone Interface (mg/L)

CORE DATA SOURCE HISTORY

Excavation “About 1990” SVE in 1998 Total Chlorinated Ethenes

160 156 152 148 115 29 17 16 16 15

1971 1975 1979 1983 1987 1991 1995 1999 2003 2007

• Chl. Eth. (mg/L):

Year

Median RPD = 7%

Site #1: Solvent Building

61

OU3-9 OU3-10 OU3-11 OU3-12

Building 780 Source Area

50 100 150 200

50 100 150 200

1973 50 mg/L 15-100% TCE

(Decreasing ov er time)

Presumed source area

1971 160 mg/L 19% TCE Arrival Time Max Concentration % Parent Compound

Former paint stripping/solvent recycling facility (1970s – 1980s) (results for 1,1,1-TCA and 1,2-DCA not shown)

50 100 150 200

1976 1.4 mg/L NA

We see plume arrivals that make sense

• Declining TCE

Source, attenuation along plume

• Attenuation

pattern reflects some past remediation efforts (excavation) but maybe not all (SVE, P&T)

• Transition from

TCE to 1,1,1-TCA

62

KEY PATTERNS:

1 2 3 4 5 6 7 20 40 60

Depth into Low k Zone (ft) Equivalent Porewater Concentration (mg/L)

10 20 30 40 50 60 70 80 90

Concentration at Interface (mg/L)

10 20 30 40 50 60 70 80 90

Concentration at Interface (mg/L)

10 20 30 40 50 60 70 80 90

Concentration at Interface (mg/L)

10 20 30 40 50 60 70 80 90

Concentration at Interface (mg/L)

1 2 3 4 5 6 7 20 40 60

Depth into Low k Zone (ft) Equivalent Porewater Concentration (mg/L)

2 4 6 8 10 20 40 60

Depth into Low k Zone (ft) Equivalent Porewater Concentration (mg/L)

2 4 6 8 10 20 40 60

Depth into Low k Zone (ft) Equivalent Porewater Concentration (mg/L)

Source History Soil Core Data

OU3-3 OU3-4 OU3-5 OU3-6

Former Building 106 Source Area - dry cleaner (1962 – 1990)

Constant source over time at each location, but less penetration into lower-k unit and lower concentrations moving downgradient

Site #2: Dry Cleaner Site

63

OU3-1 OU3-2 OU3-4 OU3-3 OU3-5 OU3-6 GW Flow Direction

Presumed source area

Building 106 Source Area

1962 78 mg/L 91% PCE 1971 50 mg/L 86% PCE 1976 32 mg/L 72% PCE 1990 23 mg/L 13% PCE Arrival Time Max Concentration % Parent Compound

20 40 60 80 100

20 40 60 80 100

20 40 60 80 100

20 40 60 80 100

Former Dry Cleaner (1962 – 1990)

We see plume arrivals that make sense

• Constant PCE

Source

• Attenuation

and biodegradation along groundwater flowpath

64

Site Locations Total Source Histories*

Navy Air Station Jacksonville 9 17 Connecticut industrial site 8 8 Ontario industrial site 1 1 Dover AFB 4 8 Florida manufacturing site 1 1

* Each location can have a separate source history for each COC

Where has this been applied?

65

$- $0.20 $0.40 $0.60 $0.80 $1.00 $1.20 $1.40 $1.60 $0 $50 $100 $150 $200 $250 $300 $350 $400 5 10 15 Cost per Vertical ft ($ K) Total Cost ($ K) Number of Locations Cored Total Cost Cost per ft $- $0.30 $0.60 $0.90 $1.20 $1.50 $1.80 $0 $50 $100 $150 $200 $250 0.5 1 1.5 2 2.5 Cost per Vertical ft ($ K) Total Cost ($ K) Soil Sampling Frequency (ft per sample) Total Cost Cost per ft

# of Locations Cored Soil Sampling Frequency

Cost Assessment: Cost Drivers

66

• Where MNA has been proposed, but is regulators are

concerned about source is not being addressed

• Sites where “source removal” is needed, but you want to

make the case that SZNA can do the job

“EPA, therefore, expects…” 67

When should you consider source history?

67

Conclusions

• Soil cores have a past
• New ESTCP Tools help you unlock it
• Method worked well at two sites in Florida
• Knowing source history helps manage

sites

68

SERDP & ESTCP Webinar Series

Final report and free software

https://www.serdp-estcp.org/Program- Areas/Environmental-Restoration/Contaminated- Groundwater/Persistent-Contamination/ER-201032

Charles Newell cjnewell@gsi-net.com; 713-522-6300

SERDP & ESTCP Webinar Series

Q&A Session 2

70

SERDP & ESTCP Webinar Series

The next webinar is on January 22

Bio-Based Methodologies for the Production of Environmentally Sustainable Materials

https://www.serdp-estcp.org/Tools-and-Training/Webinar-Series/01-22-2015

71

SERDP & ESTCP Webinar Series

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