Second Five-year Review Report for Sonford Products Superfund Site Rankin County Mississippi


SECOND FIVE-YEAR REVIEW REPORT FOR
SONFORD PRODUCTS SUPERFUND SITE
RANKIN COUNTY, MISSISSIPPI

SEPA

DECEMBER 2023

Prepared by

U.S. Environmental Protection Agency
Region 4
Atlanta, Georgia

CAROLINE
FREEMAN

Digitally signed by CAROLINE
FREEMAN

Date: 2023.12.20 12:45:55
-05'00'

Caroline Y. Freeman, Director

Superfund & Emergency Management Division

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[This Page Intentionally Left Blank]

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Table of Contents

LIST OF ABBREVIATIONS AND ACRONYMS	iv

I.	INTRODUCTION	1

Site Background	1

FIVE-YEAR REVIEW SUMMARY FORM	2

II.	RESPONSE ACTION SUMMARY	5

Basis forTaking Action	5

Response Actions	8

Status of Implementation	14

Institutional Control (IC) Review	16

Systems Operations/Operation and Maintenance (O&M)	19

III.	PROGRESS SINCE THE PREVIOUS REVIEW	19

IV.	FIVE-YEAR REVIEW PROCESS	19

Community Notification, Community Involvement and Site Interviews	19

Data Review	20

Site Inspection	25

V.	TECHNICAL ASSESSMENT	26

QUESTION A: Is the remedy functioning as intended by the decision documents?	26

QUESTION B: Are the exposure assumptions, toxicity data, cleanup levels and RAOs used at the time

of the remedy selection still valid?	26

QUESTION C: Has any other information come to light that could call into question the
protectiveness of the remedy?	28

VI.	ISSUES/RECOMMENDATIONS	28

VII.	PROTECTIVENESS STATEMENT	30

VIII.	NEXT REVIEW	30

APPENDIX A - REFERENCE LIST	A-l

APPENDIX B - CURRENT SITE STATUS	B-l

APPENDIX C - SITE CHRONOLOGY	C-l

APPENDIX D - SITE MAPS	D-l

APPENDIX E - PRESS NOTICE	E-Error! Bookmark not defined.

APPENDIX F - INTERVIEW FORMS	F-l

APPENDIX G - SITE INSPECTION CHECKLIST	G-l

APPENDIX H - SITE INSPECTION PHOTOS	H-l

APPENDIX I - DETAILED DATA ANALYSIS	1-1

APPENDIX J - DETAILED ARARS REVIEW TABLES	J-l

APPENDIX K - SCREENING-LEVEL RISK REVIEW	K-l

Tables

Table 1: Site COCs, by Media	7

Table 2: OU-1 RAOs for Subsurface Contamination	9

Table 3: OU-1 Subsurface Soil Cleanup Goals	10

Table 4: OU-1 Groundwater Cleanup Goals	11

li

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Table 5: OU-2 RAOs for Surface Contamination	12

Table 6: OU-2 Cleanup Goals for Surface Soil	13

Table 7: OU-2 Cleanup Goals for Sediment and Surface Water	14

Table 7: Summary of Planned and/or Implemented Institutional Controls (ICs)	17

Table 8: Protectiveness Determinations/Statements from the 2018 FYR Report	19

Table 9: Comparison of Select COC Concentrations in 2019 and 2021	 22

Table 10: Summary of Maximum Surface Soil COC Concentrations in 2019 and 2021	24

Table 11: Summary of Dioxin Surface Soil Samples exceeding EPA's Industrial RSL in 2019	24

Table C-l: Site Chronology	C-l

Table 1-1: Percent Mass Reduction of PCP from I SCO Pilot Test	1-1

Table J-l: Review of Cleanup Levels Against Current Standards	J-2

Table K-l: Screening-Level Vapor Intrusion Evaluation	K-2

Table K-2: Screening-Level Risk Evaluation of On-Site Surface Soil Cleanup Goals	K-3

Table K-3: Screening-Level Risk Evaluation of Off-Site Dioxin Surface Soil Cleanup Goal	K-3

Table K-4: Screening-Level Risk Evaluation of Surface Soil Samples, 2019	K-4

Table K-5: Screening-Level Risk Evaluation of Health-based Groundwater Cleanup Goals	K-5

Table K-6: Screening-level Risk Evaluation of the OU-2 Surface Water Cleanup Goals	K-5

Figures

Figure 1: Site Vicinity Map	4

Figure 2: Institutional Control Map	18

Figure D-l: Surface Soil and Sediment Exposure Units Evaluated in the 2009 Human Health Risk

Assessment	D-l

Figure D-2: Proposed Sampling Locations to Delineate Site Contamination in OU-2 Surface Soils	D-2

Figure D-3: Location of the ISCO Treatment Area	D-3

Figure D-4: Groundwater Sampling Locations, 2019	D-4

Figure D-5: Groundwater Sampling Locations, 2021	D-5

Figure D-6: Manhole Sampling Locations Along Site Sewer Lines	D-6

Figure D-7: PCP Groundwater Plume, 2015	D-7

Figure D-8: Dioxin Groundwater Plume, 2015	D-8

Figure D-9: Surface Soil Sampling Locations, 2019 and 2021	D-9

in

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LIST OF ABBREVIATIONS AND ACRONYMS

Alpha-BHC Alpha-Hexachlorocyclohexane

ARAR	Applicable or Relevant and Appropriate Requirement

bis	Below Land Surface

CERCLA	Comprehensive Environmental Response, Compensation, and Liability Act

CFR	Code of Federal Regulations

COC	Contaminant of Concern
Delta-BHC Delta-Hexachlorocyclohexane

DDE	l,l-Dichloro-2,2-bis(p-chlorophenyl)ethylene

DDT	l,l,l-Trichloro-2,2-bis(p-chlorophenyl)ethane

DU	Decision Unit

EPA	United States Environmental Protection Agency

ESD	Explanation of Significant Differences

FYR	Five-Year Review

Gamma-BHC Gamma-Hexachlorocyclohexane

HQ	Hazard Quotient

IC	Institutional Control

I SCO	In-Situ Chemical Oxidation

ISEB	In-Situ Enhanced Bioremediation

ISM	Incremental Sampling Methodology

LLDPE	Linear Low-Density Polyethylene

MCL	Maximum Contaminant Level

MDEQ	Mississippi Department of Environmental Quality

|ig/kg	Micrograms per Kilogram

|ig/L	Micrograms per Liter

mg/kg	Milligrams per Kilogram

MPE	Multi-Phase Extraction

MS TRG	Mississippi Target Remedial Goal

N	Lab qualifier for presumptive evidence that the analyte is present and is reported as a

tentative dentification.

J	Lab qualifier for an estimated value

0	Other lab qualifier

NA	Not Applicable

NAPL	Non-Aqueous Phase Liquid

NCP	National Contingency Plan

ng/kg	Nanograms per Kilogram

ng/L	Nanograms per Liter

NPL	National Priorities List

nv	Nonvolatile

O&M	Operation and Maintenance

OU	Operable Unit

PCP	Pentachlorophenol

PFAS	Per- and Polyfluoroalkyl Substances

PRP	Potentially Responsible Party

RAO	Remedial Action Objective

iv

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ROD

Record of Decision

RPM

Remedial Project Manager

RSL

Regional Screening Level

SVOC

Semi-Volatile Organic Compound

TCDD TEQ

2,3,7,8-Tetra chlorodibenzo-p-dioxin Toxic Equivalency Concentration

UCL

Upper Confidence Limit

UU/UE

Unlimited Use/Unrestricted Exposure

VISL

Vapor Intrusion Screening Level

VOC

Volatile Organic Compound

V

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I. INTRODUCTION

The purpose of a five-year review (FYR) is to evaluate the implementation and performance of a
remedy to determine if the remedy is and will continue to be protective of human health and the
environment. The methods, findings and conclusions of reviews are documented in FYR reports such as
this one. In addition, FYR reports identify issues found during the review, if any, and document
recommendations to address them.

The U.S. Environmental Protection Agency (EPA) is preparing this FYR pursuant to the Comprehensive
Environmental Response, Compensation, and Liability Act (CERCLA) Section 121, consistent with the
National Contingency Plan (NCP) (40 Code of Federal Regulations (CFR) Section 300.430(f)(4)(ii)), and
considering the EPA policy.

This is the second FYR for the Sonford Products Superfund site (the Site). The triggering action for this
statutory review is the signature date of the previous FYR. The FYR has been prepared because
hazardous substances, pollutants or contaminants remain at the Site above levels that allow for
unlimited use and unrestricted exposure (UU/UE).

The Site consists of two operable units (OUs). OU-1 addresses contaminated subsurface media,
including soil, non-aqueous phase liquid (NAPL), and on-site and off-site shallow groundwater
contamination. OU-2 addresses contaminated surface media, including surface soil, sediment and
surface water. This FYR Report addresses both OUs.

The EPA remedial project manager (RPM) Donovan Godbee led the FYR. Participants included support
from the EPA RPM Jana Dawson, the EPA risk assessor Kevin Koporec, the EPA hydrogeologist Bill
Osteen, the EPA community involvement coordinator Brenda Bonner, Mississippi Department of
Environmental Quality (MDEQ) project manager Jimmie Crellin, and Johnny Zimmerman-Ward and
Claire Marcussen with the EPA support contractor Skeo. The review began on 2/10/2023. Appendix A
provides documents reviewed as part of the FYR. Appendix B provides site status information.

Appendix C provides the Site's chronology of events.

Site Background

The 6-acre Site is located on Payne Drive in Flowood, Rankin County, Mississippi, about 5.2 miles east
of Jackson, Mississippi (Figure 1). The Site includes the former Sonford Products parcel, an
undeveloped parcel to the south referred to as the Wixson parcel, and contaminated groundwater. A
chain link fence surrounds the perimeter of both parcels. The Payne Drive neighborhood is west of the
former Sonford Products parcel. The residential area includes permanent and mobile homes. A
concrete septic tank manufacturing facility is active on the Sonford Products parcel. It uses and
stores septic tanks and heavy machinery on site. Dense woods cover the Wixson parcel. This parcel is
bordered by railroad tracks to the west, the Sonford Products parcel to the north, wooded areas to the
east, and a commercial business to the south. Wooded areas are north of the neighborhood and the
Sonford Products parcel. Commercial businesses and a highway are west of the neighborhood.
Overland flow from the Site primarily flows south into the adjacent forested wetland and along a
drainage ditch on the southwestern part of the site property.

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From 1972 to 1985, two separate chemical processing plants were operated on site, first by Sonford
International, then by Sonford Products. The operations of both companies involved turning solid
pentachlorophenol (PCP) into liquid formulations. Sonford International was active on site from 1972
to 1980. It produced a water-soluble product used for the short-term protection of wood products
from mildew. Sonford Products was active on site from 1980 to March 1985. It produced an oil-soluble
PCP product used for the long-term protection of wood products and products to control pests, mold
growth and sap stains in freshly cut lumber. Facility operations released dioxin, PCP, pesticides and
metals to the air, soil, groundwater, surface water and sediment. Sonford Products ceased all
operations after receipt of a cease-and-desist order from the town of Flowood. The EPA has not
identified a potentially responsible party (PRP) that is available or financially viable to conduct
site remediation.

The surficial aquifer at the Site consists of sands and gravels and is typically encountered at
approximately 10 feet to 14 feet below land surface (bis). The general direction of groundwater flow is
west-northwestward across the Site, crossing an unused railroad spur into the neighborhood. The
surficial aquifer is not currently used as a drinking water source. Residents near the Site are connected
to the municipal water. There are no known private wells in the surficial aquifer in the area. A
municipal supply well (PW01) northwest of the Sonford Products parcel and in the deep aquifer is
sampled regularly to ensure there are no impacts from site-related contamination.

Three deeper aquifers supply drinking water in the site area: the Cockfield Formation, the Sparta Sand
Formation, and the Wilcox Group. The EPA believes groundwater contamination is confined to the
surficial aquifer because a clay unit prevents migration from the contaminated surficial aquifer to the
deeper drinking water aquifers. Samples from an on-site groundwater monitoring well at 227 feet bis
have not shown site-related contamination.

FIVE-YEAR REVIEW SUMMARY FORM

SITE IDENTIFICATION

Site Name: Sonford Products

EPA ID: MSD086556388

| Region: 4

State: MS

City/County: Flowood/Rankin |

SITE STATUS

| NPL Status: Final |

Multiple OUs?

Has the Site achieved construction completion? 1

Yes

[

Lead agency: EPA

REVIEW STATUS

Author name: Donovan God bee

Author affiliation: EPA with support provided by Skeo

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Review period: 2/10/2023 - 10/1/2023
Date of site inspection: 4/18/2023
Type of review: Statutory
Review number: 2
Triggering action date: 12/19/2018

Due date (five years after triggering action date): 12/19/2023

3

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Figure 1: Site Vicinity Map

Fiowood, Mississippi

N Sonford Products Superfund Site

A Town of Fiowood, Rankin County, Mississippi

Disclaimer: This map and any boundary lines within the map are approximate and subject to change.
The map is not a survey. The map is for informational purposes only regarding EPA's response actions
at the Site. Map image is the intellectual property of Esri and is used herein under license. Copyright ©
2020 Esrl and Its licensors. All rights reserved. Sources: Esri. Maxar, Microsoft. Map data ©
OpenStreetMap contributors. Microsoft. Facebook. Inc. and its affiliates, Esri Community Maps
contributors. Map layer by Esri, Rankin County GIS and the 2020 Remedial Action Phase 1 Report.

Last Modified: 6/28/2023

Payne Dri\
Neighbortjo

4

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II. RESPONSE ACTION SUMMARY

Basis for Taking Action

MDEQ (formerly the Mississippi Department of Natural Resources) classified the facility as a hazardous
waste generator in 1980. In 1982, MDEQ requested that site operators sample the process stack for
PCP emissions and determined site operators needed to reduce emissions by at least 10-fold to protect
nearby residents. In June 1983, a reactor containing site contaminants caught fire and a vapor cloud
from the burning chemicals migrated over the adjacent residential area. Local fire departments and a
representative from the Mississippi Bureau of Pollution Control (MBPC) responded to the fire at the
Site. In July 1983, MDEQ instructed site operators to submit a plan to reduce emissions from the PCP
production process and cease production of specific products and then cease all operations on or
before March 1, 1985.

In February 1985, the mayor of the town of Flowood required that Sonford Products cease and desist
all operations in Flowood. At the end of March 1985, MDEQ required that site operators eliminate
environmental emissions, remove or sell all materials stored in tanks or in bulk form, and
decontaminate the facility. In April 1985, site operators spilled liquid PCP into site wetlands and, with
MDEQ's assistance with addressing the spill, the EPA assumed responsibility for performing several
removal actions between 1985 and 2008. The removal actions are described further in the following
section of the FYR Report. The EPA finalized the Site's listing on the Superfund program's National
Priorities List (NPL) in 2007 to address remaining contaminated soil, sediment, surface water and
groundwater from plant operations. The contaminants of concern (COCs) were semi volatile organic
compounds, including PCP, dioxins, pesticides, volatile organic compounds, and metals (Table 1).

The EPA conducted a risk assessment at the Site in 2009. It addressed four primary exposure areas (see
Appendix D, Figure D-l):

• On-site Operations Area (Sonford Products parcel).

• On-site Wooded Area (Wixson parcel).

• Off-site Residential Area (west of Sonford Products parcel).

• Off-site Wooded Area (east of Sonford Products parcel).

All COCs in soil/dry sediment and surface water at the Site indicated that residential, trespasser and
industrial worker exposures resulted in unacceptable cancer risks, and residential, industrial worker
and construction worker exposures resulted in unacceptable noncancer hazards. The EPA also
evaluated future residential exposure to groundwater which demonstrated cancer risks and noncancer
hazards were exceeded due to a number of COCs.

In 2010, the EPA completed an addendum to the human health risk assessment to evaluate OU-2
exposures to dioxin in surface soil via incidental ingestion and dermal contact, as well as surface water
via incidental ingestion. The 2010 risk assessment identified dioxins at concentrations posing potential
noncancer hazards in the surface soil and surface water at the Payne Drive neighborhood west of the
Sonford parcel, at the Sonford parcel, and at the wooded Wixson parcel to the south. The dioxin cancer
risk for the current and future land use scenario indicate that cancer risks occur above the upper end
of the EPA's risk management range of 1 x 10~6 to 1 x 10~4 due to soil and sediment exposures in the

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On-site Operations Area, the On-site Wooded Area, and the Off-site Wooded Area for residents (adults
and children) and industrial workers.

The EPA completed an ecological risk assessment in 2010. It indicated that unacceptable risks to
ecological mammal and bird populations were present in soil and sediment for site-related contaminants.

6

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Table 1: Site COCs, by Media

coc

Surface
Soil

Subsurface
Soil

Groundwater

Surface Water

Sediment

Dioxin

Dioxirr'

X

X

X

X

X

Pesticides

Aldrin

X

-

X

-

-

alpha-Hexachlorocyclohexane
(alpha-BHC)

X

-

X

-

-

delta-BHC

X

-

X

-

-

Gamma-BHC

X

X

-

X

X

l,l-Dichloro-2,2-bis(p-
chlorophenyl)ethylene (DDE)

X

-

-

-

-

1,1, l-Trichloro-2,2-bis(p-
chlorophenyl)ethane (DDT)

X

-

-

-

-

Dieldrin

X

-

-

-

-

Heptachlor epoxide

-

-

X

-

-

Semi-volatile Organic Compounds (SVOCs



2,3,4,6-Tetrachlorophenol

-

-

X

-

-

2,4,6-Trichlorophenol

-

-

X

-

-

2-Methylnaphthalene

-

-

X

-

-

Isophorone

-

-

X

-

-

Naphthalene

-

-

X

-

-

PCP

X

X

X

-

X

Inorganic Compounds

Iron

-

-

X

-

-

Manganese

-

-

X

-

-

Mercury

X

-

-

-

X

Volatile Organic Compounds (VOCs)

1,1,1-Trichloroethane

-

-

X

-

-

1,2-Dichloropropane

-

-

X

-

-

4-Methyl-2-pentanone

-

-

X

-

-

Acetone

-

-

X

-

-

Benzene

-

-

X

-

-

cis-l,2-Dichloroethene

-

-

X

-

-

Cyclohexane

-

-

X

-

-

Ethylbenzene

-

-

X

-

-

Isopropylbenzene

-

-

X

-

-

Methylcyclohexane

-

-

X

-

-

Methylene chloride

-

-

X

-

-

Total xylenes

-

-

X

-

-

Tetrachloroethene

-

-

X

-

-

Toluene

-

-

X

-

-

Trichloroethene

-

-

X

-

-

Vinyl chloride

-

-

X

-

-

Notes:

a. Common name for 2,3,7,8-tetrachlorodibenzo-p-dioxin, or TCDD.

X = COC in the medium.

- = not a COC in the medium.

Sources: Table 7 and Table 8 of the Site's OU-12009 ROD and Table 26 of the Site's 2010 OU-2 ROD.

7

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Response Actions

In April 1985, plant operators spilled about 2,000 gallons of PCP into the wetlands on the Wixson
parcel immediately south of the facility. The Mississippi Department of Natural Resources (now MDEQ)
conducted initial spill response activities to begin wetland remediation, and then the EPA assumed
responsibility for the remainder of the response actions. Under its removal authority, the EPA
completed the removal action in May 1985. It included digging up and removing about 2,500 cubic
yards of contaminated soil, with off-site disposal of the soil at a permitted facility. The EPA also
disposed of about 10,000 gallons of oil and treating solution at a permitted off-site incineration facility
along with about 100,000 gallons of wastewater. From April 1985 to January 1989, the Sonford
Products facility was unoccupied.

In September 1989, MBPC completed a preliminary reassessment for the Sonford Products facility and
recommended no further remedial action for the Site. In January 1989, a trucking company began
leasing the property. The length of time the trucking company leased the property is unknown.

Changes in site conditions, which included a multi-family residential structure with people living and
working at the Site, prompted the need for an updated preliminary assessment and site investigation
(PA/SI). In 2004, the EPA prepared a PA/SI for the Site in March 2007 that supported the Site's listing
on the NPL.

In January 2008, during the EPA's remedial investigation, the EPA conducted a visual inspection of the
Site to determine whether potential exposures were occurring. Based on visual evidence at the Site
and interviews of local residents, the EPA confirmed that children from the nearby residential area had
been trespassing on site. The EPA found evidence of all-terrain vehicles traffic bypassing the current
gate to access the site property and traveling across contaminated areas of the Site. Based on these
findings and surface soil data, the EPA initiated an emergency response action to install a fence to
prevent future trespassing and potential exposures to the contaminated soils. Fence installation
finished in March 2008.

To manage site investigations and cleanup, the EPA divided the Site into two OUs, which are
described below.

OU-1 Subsurface Contamination

The EPA selected the long-term cleanup plan for OU-1 in the Site's 2009 OU-1 Record of Decision (ROD)
to address subsurface soil deeper than 1-foot bis and on-site and off-site shallow groundwater. Table 2
shows the remedial action objectives (RAOs) that the EPA identified for OU-1 media.

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Table 2: OU-1 RAOs for Subsurface Contamination

Medium

RAO

Subsurface
soil

• Prevent exposure of human receptors to contaminated site subsurface soils that contain
concentrations in excess of remedial goal concentrations.

• Prevent migration and leaching of contaminants from site subsurface soils to groundwater that
could result in groundwater contamination in excess of federal drinking water standard maximum
contaminant levels (MCLs) or risk-based levels.

Groundwater

• Prevent migration of contaminated groundwater off site.

• Prevent ingestion or direct contact with groundwater containing constituents at concentrations in
excess of remedial goal concentrations.

• Restore groundwater in the contaminated aquifer that is a current or potential drinking water
source to MCLs or risk-based levels.

• Treat or remove NAPL sources from the subsurface and surficial aquifer.

• Eliminate leaching of NAPL into groundwater to prevent exceedance of remedial goal
concentrations.

Source: Section 9.1 of the Site's 2009 ROD.

The major components of the remedy selected in the 2009 OU-1 ROD include:

• Extraction of NAPL with dedicated extraction wells if sufficient volumes are present to
allow collection.

• Application of a chemical oxidant-based product to induce chemical degradation of
contamination in on-site subsurface soil, residual NAPL/source area zones, and on-site and
off-site groundwater.

• Treatment of off-site shallow groundwater using in-situ enhanced bioremediation (ISEB)
technology to enhance subsurface geochemistry to promote microbial growth and metabolism.

• Supplementation of the existing monitoring well system with additional monitoring wells, as
necessary, to ensure adequate coverage of the contaminated groundwater plume.

• Monitoring of on-site and off-site groundwater to assess the progress of contaminant mass/
concentration reduction by the chemical oxidation and ISEB.

• Implementation and monitoring of institutional controls to limit disturbance on portions of the
site property and to ensure that the groundwater from the contaminated surficial aquifer is not
used for drinking water purposes until unlimited use conditions are achieved or there are no
unacceptable risks associated with the Site.

The EPA developed cleanup goals for the Site's subsurface soil (Table 3) and groundwater (Table 4).
Subsurface soil cleanup goals are based on an EPA Directive (Dioxin), groundwater protection value
calculated using site specific values (PCP), and lxlO"6 cancer risk based on direct contact. Groundwater
cleanup goals are based on the Federal Maximum Contaminant Level (MCL); in cases where the MCL is
not available for a specific groundwater COC, the cleanup goal is a risk-based value corresponding to a
cancer risk of lxlO"6, a non-cancer hazard index of 1, or the Mississippi Target Remedial Goal (MS TRG).

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Table 3: OU-1 Subsurface Soil Cleanup Goals

coc

Cleanup Goal (ng/kg)

Basis

Dioxin

5

EPA directive3

PCP

60

Groundwater protection

gamma-BHC

28,989

Human health risk assessment

Notes:





a. EPA Office of Solid Waste and Emergency Response Directive 9200.4-26 Approach for Addressing Dioxin

in Soil at CERCLA and RCRA Sites. April 1998.



Hg/kg = micrograms per kilogram





Source: Table 7 of the Site's OU-12009 ROD.



10

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Table 4: OU-1 Groundwater Cleanup Goals

coc

Cleanup Level (ng/L)

Basis for Cleanup Level

Risk at Cleanup Level1

Dioxin

Dioxin

0.00003

MCL

-

Pesticides

Aldrin

0.004

MS TRG

-

alpha-BHC

0.01

MS TRG

-

delta-BHC

0.06

Human health risk-based level

106 excess cancer risk

Heptachlor epoxide

0.2

MCL

-

SVOCs

2,3,4,6-tetrachlorophenol

110

MS TRG

-

2,4,6-trichlorophenol

6

MS TRG

-

2-methylnaphthalene

122

MS TRG

-

Isophorone

71

MS TRG

-

Naphthalene

6

MS TRG

-

PCP

1

MCL

-

Inorganic Compounds

Iron

11,000

MS TRG

-

Manganese

730

MS TRG

-

VOCs

1,1,1-Trichloroethane

200

MCL

-

1,2-Dichloropropane

5

MCL

-

4-Methyl-2-pentanone

139

MS TRG

-

Acetone

608

MS TRG

-

Benzene

5

MCL

-

cis-l,2-Dichloroethene

70

MCL

-

Cyclohexane

26,816

Human health risk-based level

HI = 1

Ethylbenzene

700

MCL

-

Isopropylbenzene

679

MS TRG

-

Methylcyclohexane

26,816

Human health risk-based level

HI = 1

Methylene chloride

5

MCL

-

Total xylenes

7,000

DWELb

-

Tetrachloroethene

5

MCL

-

Toluene

1,000

MCL

-

Trichloroethene

5

MCL

-

Vinyl chloride

2

MCL

-

Notes:







a. Cleanup levels and residual risk information presented in this table are based on the risk associated with

exposure to contamination through ingestion, dermal contact, and inhalation of VOCs while showering by

future child and adult residents.





b. The ROD mislabeled the xylene cleanup goal as an MCL when the 2009 Rl recommended EPA's drinking water

equivalent level (DWEL) 7000 ng/L for total Xylenes because the MCL of 10,000 ng/L was determined to not be

protective based on the current toxicity assessment on EPA's Integrated Risk Information System (IRIS).

Hg/L = micrograms per liter







- = value is not human health risk-based.





HI = noncancer hazard index







MS TRG = Mississippi Target Remedial Goal table, Appendix A of the MDEQ Risk Evaluation Procedures for Voluntary

Cleanup and Redevelopment of Brownfield Sites.





Source: Table 8 of the Site's OU-12009 ROD.





In 2017, the EPA issued an Explanation of Significant Differences (ESD) to record significant changes to
the 2009 OU-1 ROD and the 2010 OU-2 ROD (discussed below). The changes for OU-1 included updates

I I

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to the site layout map and facility address and increases in remedial action cost due to the extended
period of NAPL recovery operation and the volume of NAPL extracted.

OU-2 Surface Contamination

The EPA selected the long-term cleanup plan for OU-2 in the Site's 2010 OU-2 ROD to address
contaminated surface media, including:

• On-site surface soil from surface to 1-foot bis.

• Off-site soil on residential properties west of the site property (to 2 feet bis), which were
removed and temporarily stockpiled on site, and in September 2022 transported to a disposal
facility.

• Shallow sediment (from surface to 1-foot bis) associated with woodland/wetland areas in
parcels adjacent to the former operations facility.

• Shallow sediment (from surface to 1-foot bis) associated with off-site drainage ditches along
the base of a railroad bed that runs parallel to the western boundary of the facility.

• Surface water associated with off-site water features and with the woodland/wetland areas
south of the property.

Table 5 shows the RAOs identified for these media by the EPA.

Table 5: OU-2 RAOs for Surface Contamination

Medium

RAO

Surface soil

• Prevent (current and future) human exposure (direct contact and ingestion) to
contaminated on-site surface soils (on the Sonford Products parcel) above levels that pose
an unacceptable risk for industrial and commercial use.

• Reduce contaminants in on-site surface soil to levels that are protective of industrial and
commercial use.

• Prevent (current and future) human exposure (direct contact and ingestion) to
contaminated off-site surface soils (outside of the Sonford Products parcel, in the residential
area) above levels that pose an unacceptable risk for residential use.

• Reduce contaminants in off-site residential soils to levels that are protective for
residential use.

Sediment

• Prevent future human exposure (direct contact and ingestion) to contaminated sediment
above levels that pose an unacceptable risk.

• Reduce contaminant levels in sediment that are protective of ecological receptors.

Surface water

• Prevent human ingestion and direct contact with surface water above levels that pose an
unacceptable risk.

• Prevent further migration of contaminants from surface soil and sediment to the surface
water that allows for restoration of surface water.

• Restore surface water quality to meet its designated use (a rain-dependent stream).

Source: Section 9.2 in the Site's 2010 OU-2 ROD.

The EPA identified the following major remedy components in the Site's 2010 OU-2 ROD:

• Excavation of woodland/wetland sediment (south of the former facility), off-site drainage ditch
sediment, and sub-parcels of off-site residential surface soil.

• Transportation of the excavated surface soil and sediment back on site, followed by
consolidation and capping of the material on site. This was changed, however, to offsite
disposal, as is discussed in the Status of Implementation section for OU2 Surface Soil.

-------
• Backfilling of excavated areas with clean material.

• Covering of all contaminated solids on site (surface soil and sediment) with a composite
liner system to provide hydraulic isolation (i.e., prevent leaching of contaminants into
subsurface soils).

• Monitoring of surface water over time to ensure that contaminants are naturally attenuating
and will achieve levels protective of the designated surface water uses.

• Implementation of controls such as an environmental covenant to restrict surface soil
disturbance and on-site construction activity without appropriate authorization as well as
groundwater and land use restrictions.

• Engineering controls during remedial activities that may include earthwork and grading, dust
suppression and stormwater controls.

The EPA developed cleanup levels for on-site and off-site soil (Table 6), and sediment and on-site
surface water (Table 7) in the OU-2 2010 ROD.

Table 6: OU-2 Cleanup Goals for Surface Soil

coc

Soil

Cleanup goal

Risk Basis of Cleanup Goal

([Ag/kg unless otherwise noted)

Basis

On Site3

Off Siteb

Dioxin (TCDD-TEQ)

1,000 ng/kgc

78 ng/kg

Human health risk
assessment

HI = 1

PCP

23,800

State ARAR

106 excess cancer risk

Gamma-BHC

4,400

State ARAR

106 excess cancer risk

Alpha-BHC

908

State ARAR

106 excess cancer risk

Delta-BHC

3,180

State ARAR

106 excess cancer risk

Aldrin

377

State ARAR

106 excess cancer risk

DDE

16,800

State ARAR

106 excess cancer risk

DDT

16,800

State ARAR

106 excess cancer risk

Dieldrin

358

State ARAR

106 excess cancer risk

Mercury (inorganic)

61,300

State ARAR

H 1=1

Notes:

a. Cleanup goal based on industrial use

b. Cleanup goal based on residential use

c. A toxicity value for TCDD-TEQ was published in 2012 and was used to calculate a risk-based cleanup level of 720 ng/kg.

This value supersedes the levels stated in the Directive from 2010. The Dioxin cleanup goal will be formally changed in

a decision document.

d. Value obtained from risk calculations presented in: Technical Memorandum: Baseline Human Health Risk Assessment

Addendum, Sonford Products Site, July 2010.

ng/kg = nanograms per kilogram

Hg/kg = micrograms per kilogram

HI = noncancer hazard index

TCDD-TEQ = dioxin toxic equivalents

- = Cleanup goal not required for this COC in this medium

Source: Table 26 of the Site's 2010 OU-2 ROD.

-------
Table 7: OU-2 Cleanup Goals for Sediment and Surface Water

coc

Sediment
(|ig/kg unless otherwise
noted)

Cleanup
Goal
Basis

Risk Basis of
Cleanup Goal

Surface Water

{ms/l)

Cleanup
goal
Basis

Risk Basis of
Cleanup Goal

On Site

Off Site

On Site

Dioxin (TCDD-
TEQ)

450 ng/kg

450 ng/kg

Ecological
risk

Chronic to
insectivorous

mammals

0.001b

Human
health risk
assessment

10 s excess
cancer risk

PCP

12,000

12,000

Ecological
risk

HQ< 1

-

-

-

Gamma-BHC

4,400a

-

State

ARAR

106 excess
cancer risk

0.08

State
AWQC

Freshwater
Chronic Value

Alpha-BHC

-

-

-

-

-

-

-

Delta-BHC

-

-

-

-

-

-

-

Aldrin

-

-

-

-

-

-

-

DDE

-

-

-

-

-

-

-

DDT

-

-

-

-

-

-

-

Dieldrin

-

-

-

-

-

-

-

Mercury
(inorganic)

1,100

-

Ecological
risk

HQ< 1

-

-

-

Notes:

a.	Cleanup goal based on industrial use

b.	Cleanup goal based on residential use
ng/kg = nanograms per kilogram

Hg/kg = micrograms per kilogram

Hg/L = micrograms per liter

TCDD-TEQ = dioxin toxic equivalents

- = Cleanup goal not required for this COC in this medium

Source: Table 26 of the Site's 2010 OU-2 ROD.

The 2017 ESD recorded one significant change to the 2010 OU-2 ROD, which was to extend the
operating term limit for the temporary stockpiled soil and sediment described in the OU-2 ROD.

Status of Implementation

The EPA is implementing the remedial action in a phased approach for OU-1 and OU-2.
OU-1 Subsurface Contamination

The EPA implemented the Phase 1 of the OU-1 remedy from September 2012 to June 2020 to address
NAPL recovery and included the following activities:

•	Installation of injection, extraction, and vent wells.

•	Site preparation.

•	Stockpiling of offsite residential contaminated surface soil remediated from OU-2.

•	Installation of groundwater Multi Phase Extraction (MPE) and treatment system to extract free-
product NAPL from three zones.

•	MPE well decommissioning.

•	Injection well abandonment.

•	Recover NAPL using static low-flow from the extraction wells and vent wells.

14

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The EPA completed an injection well test in 2012 that indicated that there would be no problem
injecting the treated groundwater, once the NAPL had been extracted via the MPE treatment system,
with little to no back pressure, assuming the aquifer is consistent throughout the injection area.
Between June 2014 and December 2015, the EPA operated the MPE system. In 2015, the EPA
evaluated whether to continue NAPL extraction or initiate Phase 2 of the remediation using in-situ
chemical oxidation (ISCO). After it was determined that additional NAPL extraction was necessary
before ISCO, the EPA began evaluating whether to adjust the MPE system to avoid breakthrough or to
switch to static NAPL recovery. The EPA began static NAPL recovery, via low-flow pumping, in March
2017 to focus on pumping out only LNAPL and minimize removal of groundwater with LNAPL to limit
the volume of mater requiring costly treatment before disposal, decommissioned the MPE system and
abandoned injections wells in October 2017 and completed static NAPL recovery in January 2020. The
EPA disposed of the extracted NAPL at a hazardous waste disposal facility.

The EPA began the Phase 2 OU-1 remedial action in September 2020. Between 2021 and 2022, the EPA
completed the Phase 2 ISCO field pilot study and two bench-scale treatability studies to determine the
efficacy of a chemical oxidant (sodium persulfate) to treat PCP-impacted soils. The pilot study included:
1) pre-ISCO baseline soil sampling; 2) oxidant mixing in the pilot study area; 3) post-mixing soil
monitoring; and 4) post-ISCO confirmation soil sampling. The results of the studies showed that ISCO
was successful at significantly reducing PCP concentrations. However, the percent reduction observed
in the pilot study was at least an order of magnitude lower than observed during the two bench-scale
treatability studies. Based on these results, additional evaluations will be conducted prior to full-scale
implementation to increase overall treatment efficiency. In December 2022, the EPA completed a
review of the existing soil and groundwater data and recommended completing more soil and
groundwater monitoring north of the area of NAPL contamination of the former Sonford property. This
data will support refining the area that should be targeted for full-scale OU-1 soil and groundwater
remediation by ISCO. Work planning for full scale implementation of the ISCO remedy is currently ongoing.
ISEB is planned after the implementation of ISCO to address the off-site dissolved component of the
contaminated groundwater plume. Groundwater monitoring is ongoing (the Data Review section of
this FYR Report provides more information on the monitoring completed during this FYR period).

OU-2 Surface Contamination

In September 2011, the EPA completed the remedial design for OU-2 Phase 1 remedial activities and
began remedial action. The EPA removed an abandoned on-site residential structure, excavated
contaminated soils from eight residential properties in the Payne Drive neighborhood with elevated
dioxin levels, and excavated sediment and surface soil from the Western Ditch (a privately owned
drainage ditch between the Sonford Products parcel and the Payne Drive neighborhood). The EPA
restored the eight properties, including sod installation, and replacement of trees, bushes and fencing
where necessary.

In 2012 and 2014, the EPA stockpiled contaminated soils and sediment in two temporary soil stockpiles
on the Sonford parcel. Between April and July 2012, soils excavated from the Payne Drive
neighborhood along with sediment from the Western Ditch (about 5,641 cubic yards) were placed in
an on-site temporary stockpile with a 40-mil linear low-density polyethylene (LLDPE) cover and bottom
liner. A gas vent system was placed in the pile and a chain-link fence was installed around the area by
September 2012. Between January and April 2014, another 70 cubic yards of debris, extraction well
soils and vent well soils were placed in the temporary stockpile. The smaller stockpile to the north

-------
contained soils generated during investigation activities conducted on site and the larger southern
stockpile contained soils generated during off-site remedial activities.

The 2010 OU-2 ROD required that excavated soils and sediment be consolidated on site and covered
with a composite liner system to provide hydraulic isolation. In 2021, the EPA sampled the stockpile
soils and based on the results determined that, rather than placing the stockpiled soils in a permanent
storage cell on site, it would be most cost effective to remove the consolidated soils and sediment to
an off-site facility for disposal, which would also support reuse of the Site. This action removed the
need for long-term monitoring and maintenance of the contaminated material. Prior to disposal of the
stockpile, the EPA completed waste characterization sampling from each stockpile in October 2021 to
determine the appropriate waste classification and disposal location. Based on the sampling results,
the EPA determined that the northern portion of the stockpile required characterization and disposal
of as hazardous waste and the southern portion of the stockpile could be characterized and disposed
of as non-hazardous waste. The EPA completed loading and disposal of the stockpiled non-hazardous
soils in July 2022 and the hazardous soils in September 2022. The non-hazardous soils were taken off
site for disposal at a permitted facility in Mississippi. The hazardous soils were taken to a permitted
facility in Canada, where the soil was incinerated prior to disposal. The EPA re-installed the fence
around the former stockpiled soils area in September 2022.

The previous FYR determined that the industrial land use cleanup goal for surface soil of 1,000
nanograms per kilogram (ng/kg) for dioxin exceeded the default industrial regional screening level
(RSL) of 720 ng/kg based on an updated noncancer toxicity value for dioxin. The previous FYR
recommended that prior to Phase 2 completion, the EPA will determine if further delineation and
excavation is warranted to ensure no future unacceptable exposures. In response to this
recommendation the EPA is in the process of collecting supplemental surface soil and sediment
samples in OU-2. The new surface soil and sediment data will be compared to the industrial RSL of
720 ng/kg and the OU-2 ROD cleanup goal of 450 ng/kg, respectively, to further delineate site
contamination. The proposed composite sample decision units are presented in Figure D-2 for context.
Indexing the decision units to the Thiessen polygons allows the proposed composite surface soil and
sediment sample results to be compared to previous grab sample results. These additional surface soil
samples extend north, east, and south of the former Sonford facility area to include sampling in parcel
E9E-1 area east of the former Sonford facility that was cleared in 2015 but has not yet been
redeveloped as observed during the 2018 and 2023 site inspections. In addition, the EPA is collecting
additional subsurface soil samples in OU-1 to determine if remedy refinements are needed within the
former Sonford facility area. Based on characterization results, the EPA will re-evaluate the selected
remedy for OU2 (on site disposal cell) to determine if an alternative remedy, such as soil excavation,
may be preferred. The OU2 decision document will be modified as needed.

Institutional Control HQ Review

The OU-1 ROD required institutional controls to restrict subsurface soil disturbance and on-site
construction activity without appropriate authorization, restrict groundwater use, and restrict certain
land uses. The OU-2 ROD also required institutional controls to restrict surface soil disturbance and on-
site construction activity without appropriate authorization, restrict groundwater use, and put land use
restrictions in place. Both RODs indicated that a Final Institutional Controls Implementation Plan will be
developed during the remedial design. It will identify the necessary institutional controls to be
implemented. The EPA intends to develop the institutional control implementation plan as part of the

-------
remedial action to ensure appropriate restrictions are applied based on the post-construction
conditions (Table 7). Groundwater is not a part of the OU-2 remedy, however IC's for groundwater
were discussed in the OU-2 ROD. Therefore, groundwater is listed as an OU-2 IC media in Table 7.
Figure 2 shows where the planned institutional controls will be applied.

Table 7: Summary of Planned and/or Implemented Institutional Controls (ICs)

Media, Engineered
Controls, and Areas
That Do Not
Support UU/UE
Based on Current
Conditions

ICs
Needed

ICs Called for
in the
Decision
Documents

Impacted
Parcel(s)

IC

Objective

Title of IC
Instrument
Implemented and
Date (or planned)

OU-1
Subsurface

soil and
groundwater

Yes

Yes

To Be
Determined

Restrict subsurface soil
disturbance and on-site
construction activity
without appropriate
authorization, restrict
groundwater use, and
restrict certain land uses.

To be determined

OU-2
Surface
soil and
groundwater

Yes

Yes

D9H-17
D9H-7

To be determined

17

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Figure 2: Institutional Control Map

ID9H32101

i rive

Approximate Site
Boundary

Parcel

Dioxin (TEQ)
Groundwater Plume
(0.03 ng/L) - 2015

Inferred

Pentachlorophenol
Groundwater Plume
(1 ug/L) - 2015

Railroad

Custom Drive

¦

N Sonford Products Superfund Site

A Town of Flowood, Rankin County, Mississippi

I	I	I	I	I	I

Disclaimer. This map and any boundary lines within the map are approximate and subject to change.
The map is not a survey. The map is for informational purposes only regarding EPA's response
actions at the Site Map image is the intellectual property of Esri and is used herein under license.
Copyright © 2020 Esri and its licensors. All rights reserved. Sources: Esri, Maxar, Microsoft, Map
data © OpenStreetMap contributors, Microsoft, Facebook, Inc. and its affiliates, Esri Community
Maps contributors, Map layer by Esri, Rankin County GIS and the 2020 Remedial Action Phase 1
Report.

^Skeo

Last Modified: 6/7/2023

18

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Systems Operations/Operation and Maintenance fO&M)

The Site is not in the O&M phase. The remedial design has been completed and remedial action is
ongoing for OU-1. NAPL recovery was completed at OU-1 in January 2020, followed by the completion
of I SCO pilot and bench-scale treatability studies in December 2022. Groundwater monitoring is
ongoing to inform the remedial design and ensure no contaminants migrate beyond the areas
identified in the ROD. The EPA is evaluating how overall treatment efficiencies can be increased prior
to full-scale implementation of I SCO. Remedial design and remedial action are ongoing at OU-2,
including additional sampling to refine the areas of contamination.

III. PROGRESS SINCE THE PREVIOUS REVIEW

This section includes the protectiveness determinations and statements from the previous FYR Report
(Table 8).

Table 8: Protectiveness Determinations/Statements from the 2018 FYR Report

ou#

Protectiveness
Determination

Protectiveness Statement

Will be Protective

The remedy at OU-1 is expected to be protective of human
health and the environment upon completion. In the interim,
remedial activities conducted to date have adequately
addressed all exposure pathways that could result in
unacceptable risks in these areas.

Will be Protective

The remedy at OU-2 is expected to be protective of human
health and the environment upon completion. In the interim,
remedial activities conducted to date have adequately
addressed all exposure pathways that could result in
unacceptable risks in these areas.

There were no issues and recommendations in the 2018 FYR Report.

IV. FIVE-YEAR REVIEW PROCESS

Community Notification. Community Involvement and Site Interviews

The EPA issued an online news release on October 19, 2023, to announce that the FYR was
underway. A copy of the news release is included in Appendix E. The results of the review and the
completed FYR Report will be made available on EPA's site profile page:
https://www.epa.gov/superfund/sonford-products.

During the FYR process, interviews were conducted to document any perceived problems or successes
with the remedy that has been implemented to date. The interviews are included in Appendix F and
summarized below.

James C. Crellin: Mr. Crellin is the project manager for the MDEQ. He believes the site has a long
history of assessment and remediation efforts, which are currently ongoing. He indicated that while no
remedy is active at this time, pilot studies have taken place and a new phase of soil remediation is
imminent to reduce PCP in the subsurface. He is not aware of any complaints or inquiries regarding the
site cleanup process from residents in the past five years. Although institutional controls are not yet in
place at this site, MDEQ would be more comfortable if such controls were in place.

-------
Bob Wyrick and Brian Ray: Mr. Wyrick and Mr. Ray are the project manager and lead scientist,
respectively, for the selected remedial action contractor, AECOM. They stated the remedial action pilot
scale project was successful in reducing site contaminants of concern. They only collected monitoring
data during the pilot test and nearly achieved the remedial goal of a 90% reduction in PCP
concentrations. Procedures will be evaluated during full scale to optimize the remedy which is
expected to be implemented in 2024. AECOM is not the O&M contractor for the site but expect reuse
activities to resume once the OLJ1 remedy is complete.

Michael Lacey: Mr. Lacey is the owner of Lacey's Digging Services and currently operates a septic
system service business on the site. He stated he had a good overall impression of the project and was
not aware of any issues of vandalism or trespassing occuring at the site. He said EPA has kept involved
parties and neighbors informed of activities occuring at the site but expressed frustration regarding a
change in remedy.

Data Review

The EPA is still implementing the remedial action at the Site in phases. Thus, the focus of this data
review is to summarize the parts of the remedy implemented to date. Currently, this includes a
summary of the OU-1 NAPL recovery activities, the current understanding of the extent of
contaminated groundwater, a summary of initial ISCO pilot studies, and the status of surface water and
vapor intrusion monitoring.

OU-1 Phase 1 Remedial Action of NAPL

The EPA completed MPE NAPL recovery between June 2014 and December 2015 and static NAPL
recovery using extraction and vent wells between March 2017 and January 2020. NAPL was removed
when the thickness was greater than 0.1 feet. The volume of product removed during MPE operations
was 11,920 gallons. A total of 1,405 gallons of NAPL were removed during static NAPL recovery.
Generally, the efficiency of the static NAPL removal was high when the water table elevation was high.
In January 2020, the last NAPL thickness measurement within the remediation area was relatively low
(ranging from 0 feet to 1.4 feet), and the water table was relatively high. Since the efficiency of the
static NAPL removal was also low, the January 2020 data measurements suggested that the majority
of the NAPL may have been removed, which presented conditions favorable for OU-1 Phase 2 ISCO
to begin.

OU-1 Phase 2 Remedial Action Using ISCO

The EPA completed two bench-scale ISCO tests in 2015 and 2020. They showed that PCP in soil could
be reduced by >99% in the treatment area (Figure D-3).

The EPA completed the ISCO pilot study between October 2021 and April 2022 to determine the
efficacy of a chemical oxidant (sodium persulfate) to treat PCP-impacted soils. The pilot study included:
1) pre-ISCO baseline soil sampling; 2) oxidant mixing in the pilot study area; 3) post-mixing soil
monitoring; and 4) post-ISCO confirmation soil sampling.

Pre-ISCO soil sampling was completed to establish starting concentrations from which to evaluate the
effectiveness of subsequent oxidant mixing. Pre-ISCO soil samples were collected in October 2021. In
January and early February 2022, the EPA installed a rigid vinyl sheet pile in an area 10 feet wide by

20

-------
30 feet long and to approximate depths of 17 feet to 25 feet bgs to contain the oxidant in the sheet
piling and treatment area. Oxidant mixing took place starting in mid-February and performance
monitoring occurred from late February through the end of March 2022. It included weekly sampling
events for persulfate and pH following the mixing. Based on the decrease in pH, persulfate and PCP,
the EPA collected the post-ISCO samples in April 2022.

The pre- and post-ISCO samples were collected using the EPA's incremental sampling methodology
(ISM). To determine the percent mass reduction between pre- and post-ISCO, the EPA calculated 95%
upper confidence limits (UCLs) on the mean for PCP. The EPA calculated UCLs based on the four ISM
samples from each of the four decision units (DUs). Percent PCP mass reduction in DU-1 was highest
(86.9%). Similar percentage reductions occurred in DU-2 and DU-3. The deepest treatment zone (DU-4)
showed a reduction of 43.7% (Table 1-1).

The I SCO studies significantly reduced PCP concentrations, nearly achieving the remedial goal of 90%
referenced in the Site's Remedial Design Report. However, to improve PCP reduction, the EPA plans to
collect more samples in the pilot test area to see if additional PCP reduction has occurred since post-
ISCO sampling. More evaluations are taking place to enhance PCP reduction prior to full-scale
implementation of ISCO.

OU-1 Groundwater

In 2019, the EPA collected groundwater samples from the municipal well (PW01) and 19 monitoring
wells (Figure D-4) to support remedial design and monitor for changes in groundwater concentrations
that might increase the chance for vapor intrusion risk in the Payne Drive neighborhood. The EPA also
completed groundwater monitoring in 2021 to update contamination information supporting remedial
work and refine delineation of contamination east of the Site. Site wells are primarily installed in the
uppermost surficiaI aquifer and include shallow wells (designated with an S), two intermediate wells
(designated with an I, SP174I and SP177I), and one deep well (SP156). In 2021, the EPA sampled the
same wells except well SP176, which was found to be destroyed due to landscaping work. Well SP178
was sampled in its place (Figure D-5). All samples were analyzed for semi-volatile organic compounds
(SVOCs), organochlorine pesticides, dioxin, volatile organic compounds (VOCs) and PCP.

Sitewide Groundwater Quality

The 2019 data shows that PCP was the COC most frequently detected, with the highest exceedances
above the ROD cleanup goal of 1 microgram per liter (|ig/L). The highest concentrations were generally
at the former Sonford facility property, with the highest concentration (14,000 |ig/L) detected in SP171
near the source area. In 2021, the PCP concentration was lower in this well but remained elevated
(3,400 |ig/L) above the ROD cleanup goal and exceeds the cleanup goal in six other monitoring wells.
PCP exceedances were also observed downgradient of the facility property underlying the Payne Drive
neighborhood, with a 2019 PCP concentration of 1,800 |ig/L in SP177S but below the cleanup goal of
1 |ig/L in 2021 in this well. The significant decline in PCP concentrations from 2019 to 2021 is likely due
to the removal of NAPL from the subsurface between 2014 and 2020. Table 9 lists a subset of COCs
exhibiting the higher elevated exceedances of cleanup goals in 2019 versus the 2021 concentrations.
Other COCs exhibited similar patterns as PCP, with the higher concentrations in the former facility area
and lower concentrations downgradient of the facility in the Payne Drive neighborhood (as
represented by well SP177S).

-------
Table 9: Comparison of Select COC Concentrations in 2019 and 2021

COC

2009 ROD

2019

2021

Cleanup Goal (jig/L)

SP171

SP177S

SP171

SP177S

SVOCs

Isophorone

1,400 J,0

390 J

Naphthalene

44 J

PCP

14,000

1,800

3,400

0.15 J

2,3,4,6-Tetrachlorophenol

110

1,200

400 J

3.7J

VOCs

Acetone

608

7,000

1,400

1,500J

<10

Benzene

1,2-Dichloropropane

6.5

5.2

4-Methyl-2-pentanone

139

1,100

200J

370

Methylene chloride

9.7

PCE

7.3

TCE

8.3

Notes:

J = estimated value

O = other lab qualifier

Hg/L = micrograms per liter

Sources:

Sonford Products 2019 Sampling Report. Flowood, Mississippi. Prepared by Laboratory Services and Applied Science

Division. EPA Region 4. September 2019.

Sonford Products 2021 Sampling Report. Flowood, Mississippi. Prepared by Laboratory Services and Applied Science

Division. EPA Region 4. October 2021.

Several pesticides were detected above ROD cleanup goals, primarily within the former facility area
and immediately downgradient of the facility in the Payne Drive neighborhood, with the exceedances
much lower as compared to PCP and VOCs. Finally, dioxin TEQ concentrations were detected in all
wells in 2019 but below the ROD cleanup goals, with one exception. Well SP173 southwest of the
source area had a total dioxin TEQ concentration of 0.16 nanograms per liter (ng/L) (estimated
concentration) which exceeds the ROD cleanup goal of 0.03 ng/L. In 2021, the concentration in this
well was 0.21 ng/L (estimated concentration) which exceeds the ROD cleanup goal. The remaining
detections of dioxin TEQs were equal to or close to the elevated detection limits, which exceeded the
ROD cleanup goal for dioxin TEQ in all remaining wells. In 2021, the detection limits ranged from
0.039 ng/L to 0.042 ng/L and detected levels were similar to these elevated detection limits.

In 2021, landscaping work nearby destroyed the SP176 well. The SP178 well further south and cross-
gradient was sampled instead. There were few detections and no exceedance of ROD cleanup goals in
the sample from the SP178 well.

Stockpiled Soil and Waste

In 2019 and 2021, the SP340 well on the eastern side of the stockpiled waste and soils was non-detect
for all compounds other than one dioxin compound, which was below the ROD cleanup goal. The
SP341 well on the western edge of the formerly stockpiled waste soils had an exceedance of the ROD
level (1 ng/L) for PCP at an estimated concentration of 2.4 ng/L in 2019 but was below the cleanup goal
in 2021 with an estimated concentration of 0.68 ng/L.

-------
Deep Well

One deep well (SP156) was sampled on the Sonford property in 2019. It showed that all COCs were
below detection except for dioxin; however, the concentrations were below the ROD cleanup goal.
In 2021, there were dioxin and naphthalene detections in the deep-well sample from SP156 but the
concentrations were below ROD cleanup goals. The detection limit for one VOC (vinyl chloride) in 2019
and two pesticides (aldrin and alpha-BHC) in 2019 and 2021 exceeded ROD cleanup goals.

Municipal Well

In 2019, there were no detections in either a field sample or its split counterpart at municipal
well PW01. In 2021, the EPA observed detections of SVOCs in the split sample (PW01-9621) at PW01.
The counterpart field sample (PW01-0621) had no detections. None of the detections exceeded ROD
cleanup goals.

Manhole Groundwater

In 2021, the EPA collected two wastewater samples from manholes to determine if groundwater has
infiltrated into wastewater lines (Figure D-6). The sample from SP342 is located at the downstream end
of the Site, and SP359 near the source area was sampled. PCP exceeded the ROD value at SP342 but
was non-detect for PCP in the source area manhole water sample collected from Manhole SP359.
Several VOCs and SVOCs were detected in both manhole samples but the concentrations were below
ROD cleanup goals for groundwater. The detection limits for two pesticides (aldrin and alpha-BHC)
exceeded ROD cleanup goals. Dioxin TEQs were detected at concentrations of 0.05 ng/L and 0.06 ng/L
(both estimated concentrations) in SP342 and SP359, respectively. These concentrations slightly
exceed the ROD groundwater cleanup goal of 0.03 ng/L, which is a conservative comparison as the
cleanup goal is for drinking water and the samples are wastewater.

Groundwater Plumes

OU-1 groundwater monitoring is ongoing. The extent of PCP and dioxin in groundwater in 2015 are
shown in Figure D-7 and D-8, respectively, to show the extent of groundwater contamination prior to
implementation of NAPL removal and I SCO pilot studies.

Surface Soil

In 2019, the EPA collected surface soil samples at 13 locations in undeveloped areas immediately east
and south of the former Sonford facility to refine soil characterization in these areas (Figure D-9). All
samples were analyzed for SVOCs, organochlorine pesticides and dioxin. Table 10 shows that, except
for dioxin, the maximum detection is below 2009 ROD cleanup goals. The dioxin ROD cleanup goal
exceedance occurred in sample SP343 located northeast of the former waste soil stockpile area.
However, based on more current toxicity for noncancer effects, a total of four samples (SP343,
SP346, SP347 and SP348) exceeded the EPA's Regional Screening Level (RSL) based on industrial
exposure of 720 ng/kg (Table 11). These samples are located immediately west of the former waste
soil stockpile area.

In 2021, the EPA collected composite soil sample soil samples in three areas east of the eastern surface
soil samples collected in 2019 to refine the understanding of dioxin compounds in these areas. Dioxin
was detected in all samples, with dioxin TEQ values ranging from an estimated 210 ng/kg (SP358) to an
estimated 520 ng/kg (SP356). These concentrations are below the 2009 ROD cleanup goal for industrial

-------
land use and the more stringent industrial RSL of 720 ng/kg. SVOCs and organochlorine pesticides were
not analyzed for in the 2021 Surface Soil samples.

Table 10: Summary of Maximum Surface Soil COC Concentrations in 2019 and 2021



2009 ROD

Maximum (|ig/kg)

COC

Former Sonford Facility

2019

2021



Cleanup Goal (ng/kg)

Dioxin (TCDD-TEQ)

1,000 ng/kg

1,400 ng/kg

520
ng/kg

PCP

23,800

310

NA

Gamma-Hexachlorocyclohexane

4,400

3.4 N,0

NA

(gamma-BHC)







Alpha-BHC

908

0.65 J, O

NA

Delta-BHC

3,180

8.5

NA

Aldrin

377

<2.2

NA

l,l-Dichloro-2,2-bis(p-

16,800

1.0 J,O

NA

chlorophenyl)ethylene (DDE)







1,1, l-Trichloro-2,2-bis(p-

16,800

0.79 N, J, O

NA

chlorophenyl)ethane (DDT)







Dieldrin

358

<4.4

NA

Notes:







Hg/kg = micrograms per kilogram







ng/kg = nanograms per kilogram







N = there is presumptive evidence that the analyte is present; the analyte is reported as a tentative

identification.







NA = COC was not analyzed for in 2021 Surface Soil sample





J = estimated value







O = other lab qualifier







Bold value = concentration in soil exceeds the 2009 ROD cleanup goal.





Sources:







Sonford Products 2019 Sampling Report. Flowood, Mississippi. Prepared by Laboratory Services and Applied

Science Division. EPA Region 4. September 2019.





Sonford Products 2021 Sampling Report. Flowood, Mississippi. Prepared by Laboratory Services and Applied

Science Division. EPA Region 4. October 2021.





Table 11: Summary of Dioxin Surface Soil Samples Exceeding EPA's Industrial Soil SSRG in 2019

COC

EPA Industrial Soil
SSRG (ng/kg)

Sample Result (ng/kg)

2019 Sample Location





1,400 J,0

SP343

Dioxin (TCDD-TEQ)

720

750 J,O

SP346

1,000 J,0

SP347





820 J,O

SP348

Notes:







ng/kg = nanograms per kilogram







SSRG- Site-Specific Remedial Goal





J = estimated value







O = other lab qualifier







Sources:







Sonford Products 2019 Sampling Report. Flowood, Mississippi. Prepared by Laboratory Services and Applied Science

Division. EPA Region 4. September 2019.





24

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OU-2 Surface Water

The ROD calls for monitored natural attenuation to address contaminated surface water associated
with off-site water features and with the On-site Wooded Area. Monitoring will begin after completion
of the OLJ2 soil and sediment remedy of excavation and capping in an onsite disposal cell or an
alternative remedy documented in a decision document.

OU-2 Vapor Intrusion

Based on groundwater detections of volatile compounds, the EPA conducted a soil gas survey in the
Payne Drive neighborhood in April and May 2017 in support of the previous FYR. The only detected
volatile compounds were acetone and methyl-ethyl-ketone. Both compounds were orders of
magnitude below a risk-based concentration of potential concern. The investigation concluded that
groundwater contamination from the Site is not likely to be a concern for volatilization of
contaminants into unsaturated off-site soils. Further, source area and planned groundwater remedial
actions are intended to reduce groundwater concentrations, which will reduce any potential risks from
soil vapors. There have been no more samples collected for VI, however this FYR conducts a screening
level evaluation using the most current shallow groundwater and discussed in Question B of this FYR.

Site Inspection

The site inspection took place on 4/18/2023. Participants included the EPA RPM Donovan God bee,
Jimmy Crellin with MDEQ, and Johnny Zimmerman-Ward and Claire Marcussen with the EPA support
contractor Skeo. The purpose of the inspection was to assess the protectiveness of the remedy. The
site inspection checklist and photographs are provided in Appendix G and Appendix H, respectively.

Site participants observed the perimeter chain-link fence around the Sonford Products parcel. The
entrance to the Site is through a secured gate. A sign identifies the Site as a Superfund site and
provides the EPA's contact information. The sign will be revised to reflect current project contact
information. Participants observed the former soil/sediment stockpile area where contaminated soils
and sediment had been covered and contained in a secured fenced area. The soil pile was removed for
off-site disposal in September 2022. The fenced areas will continue to serve as a consolidation area if
there are any more soils and sediment to be removed. After remedy completion, this area will be
sampled to ensure residual soil concentrations meet site cleanup goals.

Participants observed the property east of the Site, which is heavily vegetated east of the site fence.
Site inspection participants also observed the source area where NAPL extraction had occurred and
I SCO pilot tests were conducted at the south end of the former Sonford facility area. The monitoring
wells, product extraction wells and vent wells were observed near the sheet-pile wall where soil mixing
occurred for the I SCO pilot tests. The EPA is conducting more evaluations to optimize full-scale I SCO for
the Site. The property south of the Site is heavily wooded and appears to be a low area that contained
some water. A railroad and a neighborhood are immediately west of the Sonford Products parcel. Site
inspection participants also observed the public supply well in the northwest corner of the Payne Drive
neighborhood. No issues were noted during the inspection.

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¥. TECHNICAL ASSESSMENT

QUESTION A: Is the remedy functioning as intended by the decision documents?

Question A Summary:

Yes, the remedy implemented to date is functioning as intended. The EPA implemented a phased
approach to OU-1 and OU-2 and expects to begin full-scale OU-1 Phase 2 (ISCO) soon. The OU-1
remedy to date includes extraction of NAPL and ISCO pilot studies at the former Sonford Products
parcel. Following the NAPL extraction using the MPE system from 2014 to 2015, the EPA changed to a
static NAPL recovery approach beginning in 2017 and completed the recovery in 2020. In 2021 and
2022, the EPA completed the Phase 2 ISCO field pilot study and two bench-scale treatability studies,
which showed that ISCO was successful at significantly reducing PCP concentrations. However, the
percent reduction observed in the pilot study was at least an order of magnitude lower than observed
during the two bench-scale treatability studies. Based on these results, more ISCO studies will be
conducted prior to full-scale implementation to increase overall treatment efficiency, followed by
implementation of ISEB in off-site groundwater as needed.

The OU-2 remedy to date includes excavation, on-site consolidation, and covering of contaminated
soils and sediment from the Payne Drive neighborhood and the Western Ditch. All properties identified
in the remedial design were excavated and restored. In 2014, the EPA stockpiled excavated soils and
sediment in two temporary soil stockpiles at the Site located next to each other. The smaller stockpile
to the north contained soils generated during investigation activities conducted on site and the larger
southern stockpile contained soils generated during off-site remedial activities. In 2021, the EPA disposed
the consolidated soils and sediment at off-site facilities, supporting reuse of the Site. Off site disposal of
stockpiled soils removed the need for monitoring and maintenance of the contaminated soil. The EPA
completed waste characterization sampling from each stockpile in October 2021 to determine the
appropriate waste classification and disposal location. The EPA completed loading and disposal of the
stockpiled non-hazardous soils and hazardous soils in July 2022 and September 2022, respectively.

The EPA intends to implement institutional controls as part of remedy implementation. Institutional
controls will restrict subsurface soil disturbance and on-site construction activity, groundwater use,
and certain land uses.

QUESTION B: Are the exposure assumptions, toxicity data, cleanup levels and RAOs used at the time
of the remedy selection still valid?

Question B Summary:

Some exposure assumptions are no longer valid. The EPA updated the default exposure assumptions in
2014, but the net effect of the updated exposure values on site risks and risk-based remedial levels is
not significant. Exposure assumptions have changed for parcel E9E-1 since the OU-2 ROD. According to
the 2012 OU-2 ROD, this area was heavily wooded. This area was cleared in 2015 and the land (soil)
has been disturbed. Based on the 2023 site inspection, the parcel has not yet been developed.
Therefore, current human exposure appears to be limited to site visitors/trespassers.

The EPA IRIS database (a tier 1 source for Superfund HHRAs) established a reference dose (RfD) (a
noncancer toxicity value) for 2,3,7,8-TCDD in 2012, after issuance of the OU-1 and OU-2 RODs. The

-------
final human health RfD for dioxin was approved for immediate use at Superfund sites to assess human
health risk from exposure to TCDD-Toxicity Equivalence (TCDD-TEQ) concentrations. The EPA uses
California EPA's oral cancer slope factor (a tier 3 source for Superfund HHRAs) for assessment of
cancer risks.

In June 1983, a reactor containing site contaminants caught fire and a local fire department responded.
It is unknown if firefighting foam, which may contain per- and polyfluoroalkyl substances (PFAS), was
used to extinguish the fire.

A screening-level risk evaluation of the OU-2 ROD surface soil cleanup goals by comparing them to the
EPA's RSLs shows that the on-site cleanup goals (Table K-2) are equivalent to a cancer risk that falls
within the EPA's risk management range of 1 x 10"6 to 1 x 10"4. For noncancer hazards for the
industrial/commercial worker, the cleanup goals are equivalent to a noncancer hazard quotient (HQ)
that does not exceed 1 (using proper rounding) when compared to the EPA's noncancer-based RSLs.
The off-site residential cleanup goal is equivalent to a slight exceedance of the noncancer HQ of 1, with
an HQ of 2 (1.5 rounded to 2) (Table K-3). The industrial and residential cleanup goals of 1,000 ng/kg
and 78 ng/kg likely would not currently be selected as the remedial levels based on health risk. It
should be noted, however, that on-site risks are minimized, as the former Sonford facility is secured by
a fence and current owners are instructed to not interfere with the on-site remedy. Regarding the
residential surface soil remediation, review of off-site confirmation data in the Site's OU-2 Phase 1
Remedial Action Report demonstrates that excavations in the Payne Drive neighborhood west of the
former operations area achieved dioxin (TCDD-TEQ) concentrations ranging from 1.1 ng/kg to 49 ng/kg.
Concentrations at unremediated parcels did not exceed 49 ng/kg. The dioxin concentrations remaining
in the Payne Drive neighborhood are within or below the EPA's risk management range (i.e., do not
exceed an HQ of 1 nor a cancer risk of 10"4) and therefore are protective based on health risk.

In 2019, the EPA completed more sampling east of the former Sonford facility. Screening of the
maximum concentration of site COCs detected in 2019 shows that dioxin is equal to or exceeds
noncancer threshold HQ of 1 at four locations (Table K-4) based on a default composite worker (on site
and spends most of the workday conducting maintenance activities outdoors). Due to exceedances of
the ROD cleanup goal for dioxin in several samples, the EPA collected several composite samples
further east where the exceedances occurred. The maximum composite concentration in 2021 was
below the ROD cleanup goal and equivalent to an HQ of less than 1 based on current inputs for
exposure and toxicity. The EPA is finalizing a sampling plan using a revised industrial worker cleanup
goal of 720 ng/kg for dioxin to complete further delineation to determine if any further actions are
warranted for surface soil.

A screening-level risk evaluation of the health-based groundwater cleanup goals was conducted to
determine if the cleanup goals for COCs without established MCLs and Mississippi Target Remedial
Goal (TRGs) remain valid for delta-BHC, cyclohexane, methylcyclohexane and total xylenes (Appendix
K). The analysis shows that the cleanup goals for total xylenes and cyclohexane are equivalent to
noncancer HQs greater than 1. All area residents are connected to a public drinking water supply;
however, restrictions are not in place to prevent installation of potable wells.

Due to the presence of volatile COCs in shallow groundwater, a screening-level vapor intrusion
evaluation was completed (Appendix K) using shallow groundwater data collected from monitoring

-------
wells in the residential area closest to the Site. SP177S was selected to represent this area since this is
a shallow well that exhibits the highest concentrations of volatile COCs in the Payne Drive
neighborhood downgradient of the Site. As shown in Table K-l, the cumulative cancer risks are within
the EPA's acceptable risk range of 1 x 10~4 to 1 x 10~6. The individual noncancer HQs are equal to or
below the EPA threshold of 1. However, based on cumulative HQs, the total hazard index slightly
exceeds 1. This finding suggests that the vapor intrusion pathway could be assessed further to consider
noncarcinogenic target organs, and using multiple lines of evidence, to determine if the vapor intrusion
exposure pathway is a completed exposure pathway.

Once the groundwater remedy is fully implemented, site RAOs to prevent contaminant migration off
site and restore groundwater as a current or potential drinking water source will be achieved. In the
interim, local users are connected to a public water supply. The EPA reduced leaching of NAPL sources
by extracting NAPL from the Site from 2012 to 2020. The subsurface soil RAO of preventing human
exposure is achieved by installing a fence around the former Sonford facility. The EPA is in the process
of implementing the ISCO remedy, followed by ISEB to prevent further migration and leaching from
site subsurface soils to groundwater. The EPA is also finalizing a Soil Sampling and Analysis Plan to
determine if any additional action is needed based on the more stringent Site-Specific Remedial Goal
(SSRG) for industrial soil of 720 ng/kg rather than the OU-2 ROD cleanup goal of 1,000 ng/kg.

QUESTION C : Has any other information come to light that could call into question the protectiveness
of the remedy?

No other information has come to light that could call into question the protectiveness of the remedy.

VI. ISSUES/RECOMMENDATIONS

Issues/Recommendations

OU(s) without Issues/Recommendations Identified in the FYR:

None

Issues and Recommendations Identified in the FYR:

OU(s): 1 and 2

Issue Category: Institutional Controls

Issue: All area residents are connected to a public water supply; however,
institutional controls have not yet been implemented to restrict installation of
wells in the future.

Recommendation: Implement institutional controls to restrict groundwater use
once the groundwater contamination plume has been fully characterized.

Affect Current
Protectiveness

Affect Future
Protectiveness

Party Responsible

Oversight Party

Milestone Date

Yes

EPA

EPA/State

9/1/2026

-------
OU(s): 2

Issue Category: Other
Change in Remedy



Issue: The EPA determined it would be most cost effective to take the temporary
consolidated stockpile soils and sediment to off-site facilities for disposal, which
would also support site reuse. The EPA completed removal of the stockpiled
non-hazardous soils in July 2022 and the hazardous soils in September 2022.
These actions are a change in the remedy component of constructing a
permanent storage cell on site.



Recommendation: In a decision document, document the remedy change from
containment of stockpiled contaminated surface soil, sediment, and debris in a
permanent on-site storage cell to off-site disposal of the material.

Affect Current
Protectiveness

Affect Future
Protectiveness

Party Responsible

Oversight Party

Milestone Date

No

Yes

EPA

EPA/State

12/1/2025

OU(s): 2

Issue Category: Other
Soil Cleanup Goals



Issue: The cleanup goals for dioxin in surface soil slightly exceed the EPA's
current residential and composite worker RSLs based on a noncancer HQ of 1.



Recommendation: Evaluate additional surface soil sampling results collected in
2019 and 2021 and planned for collection in 2023 to determine if dioxin in
surface soil is within the EPA's target cancer risk range and does not exceed a
hazard quotient of 1. Determine if additional actions and/or a cleanup goal
revision is needed.

Affect Current
Protectiveness

Affect Future
Protectiveness

Party Responsible

Oversight Party

Milestone Date

No

Yes

EPA

EPA/State

9/1/2025

OU(s): 2

Issue Category: Monitoring

Issue: In June 1983, a reactor containing site contaminants caught fire and a
local fire department responded. It is unknown if firefighting foam, which may
contain PFAS, was used to extinguish the fire.

Recommendation: Evaluate historical records to determine if firefighting foam
was used to extinguish the 1983 fire and, if so, consider conducting sampling for
PFAS to determine if it is present at the Site.

Affect Current
Protectiveness

Affect Future
Protectiveness

Party Responsible

Oversight Party

Milestone Date

No

Yes

EPA

EPA/State

9/1/2025

29

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VII. PROTECTIVE NESS STATEMENT

Operable Unit: 1

Protectiveness Statement

Protectiveness Determination:
Will be Protective

Protectiveness Statement: The remedy at OU-1 (including institutional controls) is expected to be
protective of human health and the environment upon completion. In the interim, remedial activities
conducted to date have adequately addressed all exposure pathways that could result in
unacceptable risks in these areas.



Operable Unit: 2

Protectiveness Statement

Protectiveness Determination:
Will be Protective

Protectiveness Statement: The remedy at OU-2 (including institutional controls) is expected to be
protective of human health and the environment upon completion. In the interim, remedial activities
conducted to date have adequately addressed all exposure pathways that could result in
unacceptable risks in these areas.

VIII. NEXT REVIEW

The next FYR Report for the Sonford Products Superfund site is required five years from the completion
date of this review.

30

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APPENDIX A - REFERENCE LIST

AECOM, 2022. Phase 2 I SCO Remedial Action: Part 1 - Focused Treatment Area Summary Report
Sonford Products Superfund Site, OU-1, Flowood, MS. Figure 1. December 2022.

Black & Veatch, 2009. Black and Veatch Special Projects Corp. Remedial Investigation Report, Sonford
Products Site, Flowood, Mississippi, Revision 1, June 2009.

Black & Veatch, 2009. Black and Veatch Special Projects Corp. Field Sampling Plan (FSP), Sonford
Products Site, Flowood, Mississippi, Revision 1, June 2009.

Black & Veatch, 2010. Black and Veatch Special Projects Corp. Final Ecological Risk Assessment Sonford
Products Site Flowood, Rankin County, Mississippi. August 2010.

Black & Veatch, 2010. Black and Veatch Special Projects Corp. Technical Memorandum Sonford
Products Site Baseline Human Health Risk Assessment Addendum. DCN: 49032-0107-02-A-00547R1A1.
August 2010.

Black & Veatch, 2012. Black & Veatch Special Projects Corp., Final Remedial Design, Phase 1 -
Extraction and Enhanced NAPL Recovery Basis of Design Report, Sonford Products Superfund Site,
September 2012.

Black & Veatch, 2012. Black & Veatch Special Projects Corp., Phase I Remedial Action Report, Sonford
Products Superfund Site, September 2012.

Black and Veatch, 2020. Remedial Action Report Phase 1 Revision 3. NAPL Extraction. Prepared by
Black and Veatch. June 2020.

EPA, 2009. U.S. Environmental Protection Agency, Record of Decision, Summary of Remedial
Alternative Selection, Sonford Products Superfund Site, Operable Unit 1, Flowood, Rankin County,
Mississippi. September 2009.

EPA, 2010. U.S. Environmental Protection Agency, Record of Decision, Summary of Remedial
Alternative Selection, Sonford Products Superfund Site, Operable Unit 2, Flowood, Rankin County,
Mississippi, September 2010.

EPA, 2012. U.S. Environmental Protection Agency, Region 4, Sonford Products Superfund Site Operable
Unit 2 Phase 1, Remedial Action Report. September 28, 2012.

EPA, 2013. Region 4, Environmental Protection Agency, SESD Operating Procedure Groundwater
Sampling. SESDPROC-301-R3. March 6, 2013.

EPA, 2017. Explanation of Significant Differences, Sonford Products Superfund Site, Flowood, Rankin
County, Mississippi. July 2017.

A-l

-------
EPA, 2018. First Five-Year Review Report, Region 4, Sonford Products Superfund Site. Flowood,
Mississippi. December 2018.

EPA, 2019. Sonford Products 2019 Sampling Report. Flowood, Mississippi. Prepared by Laboratory
Services and Applied Science Division. EPA Region 4. September 2019.

EPA, 2021. Sonford Products 2021 Sampling Report. Flowood, Mississippi. Prepared by Laboratory
Services and Applied Science Division. EPA Region 4. October 2021.

EPA, 2022. Technical Memorandum: Further Evaluation of Soil Remedial Goals for Groundwater
Protection, Sonford Products Superfund Site, Flowood, Rankin County, Mississippi. Prepared by EPA
Region 4. December 2022.

EPA, 2023. Final Uniform Federal Policy Quality Assurance Project Plan, Revision 1. Prepared by
Hydrogeologic for the EPA Region 4. September 2023.

A-2

-------
APPENDIX B - CURRENT SITE STATUS

Environmental Indicators

-	Current human exposures at the Site are under control.

-	Due to uncertainty regarding contaminated groundwater migration, the EPA will evaluate
current groundwater data to determine if the migration of contaminated groundwater is
stabilized.

Are Necessary Institutional Controls in Place?

I I All Q Some None

The EPA is in the process of preparing an Institutional Controls Implementation Plan and will
identify the necessary institutional controls to be implemented. The institutional controls will
be implemented as necessary as part of the final phases of remedial action to ensure
appropriate restrictions are applied based on post-construction conditions.

Has the EPA Designated the Site as Sitewide Ready for Anticipated Use?

^~j^esJ^No



Has the Site Been Put into Reuse

XI Yes Q No

A septic tank manufacturer on site constructs cement septic tanks on the site surface. Its
activities do not involve any disturbance of the subsurface.

B-l

-------
APPENDIX C - SITE CHRONOLOGY

Table C-l: Site Chronology

Event

Date

The Site housed two separate chemical processing plants

1972-1985

The Mississippi Department of Natural Resources instructed Sonford Products to cease the



production of most products and submit a plan to reduce emissions from the PCP

July 1983

production process, and cease all operations on or before March 1,1985



The mayor of the town of Flowood required that Sonford Products cease and desist all
operations in Flowood

February 5,1985

The Mississippi Department of Natural Resources inspected the Site and confirmed that

March 15,1985

manufacturing and blending operations had ceased

The EPA began the first removal action to address a 2,000-gallon spill

April 21, 1985

The EPA completed the first removal action

May 12,1985

The EPA began the OU-1 and OU-2 remedial investigation and the feasibility study for OU-1

July 13, 2006

The EPA finalized the Site's listing on the NPL

March 7, 2007

The EPA began the second removal action by installing a fence around the former Sonford

January 14, 2008

facility



The EPA completed the second removal action

March 12, 2008

The EPA completed the OU-1 and OU-2 remedial investigation

September 24, 2009

The EPA completed the OU-1 feasibility study



The EPA signed the OU-1 ROD

September 28, 2009

The EPA began the Phase 1 OU-1 remedial design

September 30, 2009

The EPA began the OU-2 feasibility study

December 18, 2009

The EPA began Phase 1 OU-2 remedial design

August 30, 2010

The EPA completed the OU-2 feasibility study

September 30, 2010

The EPA signed the OU-2 ROD



The EPA completed the Phase 1 OU-2 remedial design and began the Phase 1 remedial

September 22, 2011

action



The EPA completed Phase 1 OU-2 remedial action

September 28, 2012

The EPA completed the Phase 1 OU-1 remedial design



The EPA began Phase 1 of the OU-1 Remedial Action (NAPL extraction)

January 7, 2014

The EPA began the Phase 2 OU-1 remedial design

May 28, 2014

The EPA shut down the MPE system

December 16, 2015

The EPA began static NAPL recovery

March 7, 2017

The EPA issued an ESD for OU-1 and OU-2

July 13, 2017

The EPA completed the Site's Community Involvement Plan

April 2018

The EPA signed the Site's first FYR report

December 19, 2018

The EPA completed static NAPL recovery

January 2020

The EPA completed the Phase 2 OU-1 remedial design

June 29, 2020

The EPA began the Phase 1 OU-2 remedial action

September 30, 2020

The EPA began Phase 2 OU-2 remedial design

July 19, 2021

The EPA completed pre-ISCO soil sampling to establish baseline PCP concentrations to

October 6, 2021

evaluate the effectiveness of subsequent oxidant mixing



The EPA competed waste characterization of stockpiled soils

October 26, 2021

The EPA completed the installation of sheet-piling for the ISCO test area

February 2, 2022,

The EPA conducting oxidant mixing in the ISCO test area

February 7 to 17, 2022.

The EPA began post-ISCO test performance monitoring of the mixed slurry material for pH

February 24, 2022

and persulfate



The EPA completed post-ISCO performance monitoring

March 31, 2022

The EPA completed post-ISCO sampling of PCP

April 20, 2022

The EPA completed disposal of nonhazardous stockpiled soils at a permitted landfill in

July 20, 2022

Mississippi



The EPA completed disposal of hazardous stockpiled soils at a permitted facility in Canada,

September 21, 2022

where the soil was incinerated prior to disposal



C-l

-------
APPENDIX D-SITE MAPS
Figure D-l: Surface Soil and Sediment Exposure Units Evaluated in the 2009 Human Health Risk Assessment

Source: 2009 Remedial Investigation, Figure 6-1. Prepared by Black & Veatch Specialty Projects Corp. Revision 1. July 2009.

D-l

-------
?BPBQi:tZ«)a

,SP242.(3-711 *

i? pfr O

1111111111 mWI

> in/" " ¦¦SPO 13 (6 4*J;

[SPQ12V(2I6)]

Figure D-2: Proposed Sampling Locations to Delineate Site Contamination in OU-2 Surface Soils

m ¦¦¦¦¦¦¦¦¦¦¦ ¦¦¦¦¦¦¦¦¦¦,

® GTJ©

czaes

v; -'

.«¦ 7* i

: eossacsesi®

-C3~E3(]2£3

GjiEDCDEDi®

©S300S®

Sonford Products Superfund Site
Operable Unit 2
3506 Payne Drive
Flowoad Rankin County. Mississippi

Figure 3.2
Thiessen Polygons
On-SUe and Wood laud/Wetland
Area Surface Soil and Sediment

Pioxin TKO Results

Legend

O OU2 Decision Point Centrioid
Soil Sample Location

© Non Detect to equal to <172 pg/kg
C Greater than 0.72 to equal to 2.4 |J gAg - contained out
# Greater than 2.4 pg&g - contained in
Sediment Sample Location

A. Non Detect to equal to 0.45 pg/kg

Greater than 0.45 to equal to 2.4 pgAg - contained out

A Greater than 2.4 pgAg - contained in
Site Boundary
V'/l OU2 Surface Soil Sampling Decision Unit
| Approximate Extent of OUI Soil Mixing Area
! "Contained-in" sample within PCPspill area
I "Contained-out" sample within PCP spill area

Sample outside PCP spill area that exceeds ths Dioxin
TEQ Cleanup Level

Sample outside PCP spill area that is below the Dioxin
TEQ Cleanup Level

Data Conpartson Concentrations

coc

Concentration

Reqiriatorv Standard

Dtcodn TEQ

0.45 ml kg

R< 'D CleaTjp Level for Sediment

DkwiTBj

0.72 ua/kn

ROD Cleanuo Level for Suitace Soil

Keren TBj;

2.4 p® kg

Cootained-in Level fix Listed Waste

Results arc pssentcd in micrograms per kilogram (jig/kg j.

Analytical daii presented obtiired froai EQutS export provided by ItCL
via electronic transfer cm 16 SepEmbcr 202 L

COC = coeitanunara of concern

J = Rssufct is estiraas d be tween the method detection limit (MIX.) and the

reporting limit (RLt.

OU1 = Operable Unit 1
FCP= IVnlachlDTophcnol
ROD = Record of Decision

I.' = Compo und rat iictcctd. The Reporting Limit is shown.

Source: Final Uniform Federal Policy Quality Assurance Project Plan, Revision 1. Prepared by Hydrogeoiogic for the EPA Region 4. September 2023.

D-2

-------
Figure D-3: Location of the ISCO Treatment Area

Products

Temporary Soil
Stockpile

I * V*

^(Focused
Treatment
¦At Area

Chain Link Fencing

PPR Limited
[Partnership]
|Propertyl

¦ Wixson Property'

1 inch = 97 feet

0 37.5 75



isSfl&Qffnnriuniit



Legend

Parcel Boundary
t>: • I Treatment Area
I I Support Trailer

Source: Phase 2 ISCO Remedial Action: Part 1- Focused Treatment area Summary Report, Sonford Products Superfund Site,
OU-1, Flowood, MS. Figure 1. Prepared by AECOM. December 2022.

D-3

-------
Figure D-4: Groundwater Sampling Locations, 2019

Payne Drive

PW01

Legend

Category

Deep Well Sampled 	

Shallow Well Sampled A
Municipal Well jk>.
Not Sampled Q

UNITED STATES
ENVIRONMENTAL PROTECTION AGENCY
REGION 4

Sonford Products

Figure 1,

Well Location Map

Science Branm
933 College Stadcc. Rcac
ABwts, Georga 30S0S-2720

Source: Sonford Products 2019 Sampling Report. Flowood, Mississippi. Prepared by Laboratory Services and Applied Science Division. EPA Region 4. September 2019.

D-4

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Figure D-5: Groundwater Sampling Locations, 2021

PWOl

Legend

Deep MW

Shallow MW	A

Municipal Well	A

Not Sampled 	

'Well destroyed, not sampled
"Substituted Tor SP176

UNITED STATES
ENVIRONMENTAL PROTECTION AGENCY
REGION 4

Sonford Products

Figure 1,

Well Location Map

Rew Ser.ices Branch
58 D coiege station Roac
Wrtfrns, Georgia 3E6E6-272D

Source: Sonford Products 2021 Sampling Report. Fiowood, Mississippi. Prepared by Laboratory Services and Appiied Science Division. EPA Region 4. October 2021,

D-5

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Figure D-6: Manhole Sampling Locations Along Site Sewer Lines

FLOW

Legend

Category
Deep "2 A
Municipal J±_
No Sample ©
Sampled si\

Manhole

UNITED STATES
ENVIRONMENTAL PROTECTION AGENCY
REGION A

Sonford Products
Figure 3,

Sewer Line Transiting Site

Reis Services Branch
98a CoUege Starrier Road
AJJieos, Georga 3060S-272Q

Source: Sonford Products 2021 Sampling Report. Flowood, Mississippi. Prepared by Laboratory Services and Applied Science Division. EPA Region 4. October 2021.

D-6

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Figure D-7: PCP Groundwater Plume, 2015

WukL- UP

Sonford Products
Site

EP1S3

0,20 U

S27QJJ0



Legend

* 3h» few Vfewrtarirg WeJi

rteTTKSafc Monfixrtr^ well
\ Deeo Monwrng Weil
31 Vun
-------
Figure D-8: Dioxin Groundwater Plume, 2015

„ moi
o'oooa' j.o

Sonford Products
Site

SP182
0.012 J.O

SP1 *7.1
0.D072 J,

SP1B3
0.0012 J.O

to oooea ujO q

•£.SP171
0.0074 J.O

Sftiaa
V'NR

Ipspvsi; "

¦0011|J,0 1

Legend

+ Shallow Monitoring Well
4r Intermediate Monitoring Well
4r Deep Monitoring Well
~5r Municipal Well

C oxr {TEQ) In Groundwater (ng/L)
	Parcel Boundaries (Approximate)

BBsl

Wixson Property

A

Feet

UTM NAD83 Zone 15N. meters

200
—I

Extent of Dioxin (TEQ) in Groundwater - July 2015
Sonford Products Site
Flowood. Rankin County, Mississippi

Figure

7-3

Source: Remedial Action Report Phase 1 Revision 3. NAPL Extraction. Prepared by Black and Veatch. June 2020,

D-8

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Figure D-9: Surface Soil Sampling Locations, 2019 and 2021

SP358

Legend

2019 soil composite centers
2021 Soil Areas
+ 2021 Soil Area Centroid
• 2021 Aliquot Locations

LIMITED STATES
ENVIRONMENTAL PROTECTION AGENCY
REGION 4

Sonford Products
Figure 2,

Soil Sample Location Map

Source: Sonford Products 2021 Sampling Report. Flowood, Mississippi. Prepared by Laboratory Services and Applied Science Division. EPA Region 4. October 2021.

D-9

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APPENDIX E - PRESS NOTICE

U.S. ENVIRONMENTAL PROTECTION AGENCY

NEWS RELEASE

EPA.GOV/NEWSROOM

EPA to Review Cleanups at 40 Southeast Superfund Sites

Contact Information: reqion4press@epa.gov. 404-562-8400

ATLANTA (Oct. 19, 2023) - Today, the U.S. Environmental Protection Agency (EPA) announced that comprehensive
reviews will be conducted of completed cleanup work at 40 Superfund sites in the Southeast.

The sites, located in Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, and
Tennessee, will undergo a legally required Five-Year Review to ensure that previous remediation efforts at the sites
continue to protect public health and the environment.

"Five-Year Reviews are an integral part of the site remediation process because they help make sure remedies are
still protective," said Acting EPA Region 4 Administrator Jeaneanne Gettle. "The Southeast Region will benefit
tremendously from the full restoration of Superfund sites, which can become valuable parts of the community
landscape."

The Superfund Sites where EPA will conduct Five-Year Reviews in Calendar Year 2024 are listed below. The web
links provide detailed information on site status as well as past assessment and cleanup activity. Once the Five-Year
Review is complete, its findings will be posted in a final report at https://www.epa.gov/superfund/search-superfund-
five-vear-reviews.

Alabama

American Brass Property https://www.epa.gov/superfund/american-brass
Florida

Arkla Terra Property https://www.epa.gov/superfund/arkla-terra

Brown's Dump https://www.epa.gov/superfund/brown's-dump

City Industries, Inc. https://www.epa.gov/superfund/citv-industries-inc

Coleman-Evans Wood Preserving Co. https://www.epa.gov/superfund/coleman-evans-wood

Harris Corp. (Palm Bay Plant) https://www.epa.gov/superfund/harris-corporation-palm

Jacksonville Ash Site https://www.epa.gov/superfund/iacksonville-ash

Kassauf-Kimerling Battery Disposal https://www.epa.gov/superfund/kassauf-kimerling-th

Nocatee Hull Creosote https://www.epa.gov/superfund/nocatee-creosote

E-l

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Pioneer Sand Co. https://www.epa.aov/suoerfund/pioneer-sand-companv

Piper Aircraft Corp./Vero Beach Water & Sewer Dept. https://www.epa.aov/suDerfund/piper-aircraft-corp

Sandford Gasification Plant https://www.epa.gov/superfund/sanford-gasification

Sixty-Second Street Dump https://www.epa.aQv/superfund/sixtv-second-street

Solitron Microwave https://www.epa.aov/superfund/solitron-microwave

Tyndall Air Force Base https://www.epa.aQv/superfund/tvndall-air-force-base

United Metals, Inc. https://www.epa.aov/superfund/united-metals-inc

Whitehouse Oil Pits https://www.epa.aQv/superfund/whitehouse-Qil-pits

Georgia

Woolfolk Chemical Works, Inc. https://www.epa.Qov/superfund/woolfolk-chernical-works
Kentucky

Airco https://www.epa.aov/superfund/airco

B. F. Goodrich https://www.epa.aQv/superfund/bf-aoodrich

Paducah Gaseous Diffusion Plant (USDOE) https://www.epa.aov/superfund/paducha-aaseous-diffusion-plant
Mississippi

Sonford Products https://www.epa.aov/superfund/sonford-products
North Carolina

General Electric Co/Shephard Farm https://www.epa.aov/superfund/aeneral-electric-shepherd-farrn
North Belmont PCE https://www.epa.aov/superfund/north-belmont-pce

South Carolina

Calhoun Park Area https://www.epa.aov/superfund/search-superfund-five-vear-reviews
Gieger (C & M Oil) h tt ps : //www. e pa. a o v/s u pe rfu n d/a e ia e r

Helena Chemical Co. Landfill https://www.epa.aov/superfund/helena-chemical-landfill
Lyman Dyeing and Finishing https://www.epa.aQv/superfund/lvman-dveina-finishina
Medley Farm Drum Dump https://www.epa.aQv/superfund/medlev-farm-drum-dump
Savannah River Site (USDOE) https://www.epa.aQv/superfund/savannah-river-site
WamChem, Inc. https://www.epa.gov/superfund/wamchem

E-2

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Tennessee

American Creosote Works, Inc. (Jackson Plant) https://www.epa.aov/suoerfund/american-creosote-works-iackson
Oak Ridge Reservation (USDOE) https://www.epa.aov/supertund/oak-ridae-reservation
Ross Metals Inc. https://www.epa.aov/superfund/ross-metals

Background

Throughout the process of designing and constructing a cleanup at a hazardous waste site, EPA's primary goal is to
make sure the remedy will be protective of public health and the environment. At many sites, where the remedy has
been constructed, EPA continues to ensure it remains protective by requiring reviews of cleanups every five years. It
is important for EPA to regularly check on these sites to ensure the remedy is working properly. These reviews identify
issues (if any) that may affect the protectiveness of the completed remedy and, if necessary, recommend action(s)
necessary to address them.

There are many phases of the Superfund cleanup process including considering future use and redevelopment at
sites and conducting post cleanup monitoring of sites. EPA must ensure the remedy is protective of public health and
the environment and any redevelopment will uphold the protectiveness of the remedy into the future.

The Superfund program, a federal program established by Congress in 1980, investigates and cleans up the most
complex, uncontrolled, or abandoned hazardous waste sites in the country and endeavors to facilitate activities to
return them to productive use. In total, there are more than 280 Superfund sites across the Southeast.

More information:

EPA's Superfund program: https://www.epa.gov/superfund

ff IS IS
I * TT~

TTTTTT

E-3

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APPENDIX F - INTERVIEW FORMS

SONFORD PRODUCTS SUPERFUND SITE
FIVE-YEAR REVIEW INTERVIEW FORM

Site Name: Sonford Products

EPA ID: MSD086556388

Interviewer name: Donovan Godbee

Interviewer affiliation: EPA

Subject name: James C. Crellin

Subject affiliation: Miss. Dept. of Env.
Quality

Subject contact information: icrellingmdeq.ms.gov. 601-961-5230

Interview date: 7/28/2023

Interview time: 15:20

Interview location: MDEQ HQ, Jackson, MS

Interview format (circle one): In Person
Questionnaire

Phone

Mail

Email

Other:

Interview category: State Agency

1.	What is your overall impression of the project, including cleanup, maintenance and reuse
activities (as appropriate)? The site has a long history of assessment and remediation efforts,
which continue. There appears to be impact remaining both on and off the site in

various media.

2.	What is your assessment of the current performance of the remedy in place at the Site? No
remedy is active at this time. Pilot studies have taken place and a new phase of soil
remediation is imminent. Clean-up objectives are to reduce PCP impact by 90%.

3.	Are you aware of any complaints or inquiries regarding site-related environmental issues or
remedial activities from residents in the past five years? No.

4.	Has your office conducted any site-related activities or communications in the past five
years? If so, please describe the purpose and results of these activities. I am not aware of
any independently conducted site-related activities initiated or participated in by MDEQ in
the last five years.

5.	Are you aware of any changes to state laws that might affect the protectiveness of the Site's
remedy? No.

6.	Are you comfortable with the status of the institutional controls at the Site? If not, what are
the associated outstanding issues? Institutional controls are not in place at this site. MDEQ
would be more comfortable if such controls were in place, although current activities, which
are expected to continue for an extended period, pose no risks to exacerbation of conditions
at the site. Impediments to implementation of such controls have not been discussed to this
point.

F-l

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7.	Are you aware of any changes in projected land use(s) at the Site? No. See response to
question 6., above.

8.	Do you have any comments, suggestions or recommendations regarding the management or
operation of the Site's remedy? MDEQ is satisfied at this with upcoming soil remediation
efforts and upcoming further surficial soils assessment. MDEQ would like to see further
assessment of groundwater, sediment and surface water impacts.

9.	Do you consent to have your name included along with your responses to this questionnaire
in the FYR report? Yes.

F-2

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SONFORD PRODUCTS SUPERFUND SITE
FIVE-YEAR REVIEW INTERVIEW FORM

Site Name: Sonford Products

EPA ID: MSD086556388

Interviewer name: Donovan Godbee

Interviewer affiliation: EPA RPM

Subject name: Bob Wyrick, Brian Ray

Subject affiliation: AECOM Technical Services, Inc.

Subject contact information: 5438 Wade Park Boulevard, Suite 200, Raleigh, NC 27607
T 1-919-461-1100;

Interview date: November 3, 2023

Interview time: 9:00

Interview location: email

Interview format (circle one): In Person

Phone

Mail

Other:

Interview category: RA Contractor

1.	What is your overall impression of the project, including cleanup, maintenance and reuse activities
(as appropriate)?

Overall, the pilot scale I SCO project was successful. The results of the pilot test were favorable
and off site disposal of the onsite soil stockpile was performed. The full-scale I SCO mixing project
is moving forward as part of site remediation to return the area to reuse conditions. Reuse
activities for the site in the RA area will resume once the OU1 remedy is complete.

2.	What is your assessment of the current performance of the remedy in place at the Site?

The results of the pilot scale I SCO activities indicate the soil remedy was successful at reducing
site constituents of concern.

3.	What are the findings from the monitoring data? What are the key trends in contaminant levels
that are being documented over time at the Site?

AECOM only collected monitoring data during the ISCO Pilot study. Based on the percent
reduction in pentachlorophenol concentrations calculated by the UCL values, the monitoring
data show that ISCO was successful at significantly reducing PCP concentrations, nearly
achieving the remedial goal referenced in the RD of 90% in the Pilot study area. However, the
percent reduction observed in monitoring data collected during the pilot study was at least an
order of magnitude lower than observed during the two bench scale treatability studies. Despite
applying caustic (i.e., lime) in excess of values derived in the treatability studies (Geosyntec,
2015;2020), the pH of mixed soils dropped rapidly, which likely negatively affected oxidant
reactivity. It is possible that the base buffering capacity is highly variable at the Site. This can be
evaluated during full scale to optimize buffering capacity.

4.	Is there a continuous on-site O&M presence? If so, please describe staff responsibilities and
activities. Alternatively, please describe staff responsibilities and the frequency of site inspections
and activities if there is not a continuous on-site O&M presence.

No. AECOM has only been on-site to collect soil samples during a pilot study for soil remediation.

F-3

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5.	Have there been any significant changes in site O&M requirements, maintenance schedules or
sampling routines since start-up or in the last five years? If so, do they affect the protectiveness or
effectiveness of the remedy? Please describe changes and impacts.

Not applicable. AECOM is not conducting O&M activities.

6.	Have there been unexpected O&M difficulties or costs at the Site since start-up or in the last five
years? If so, please provide details.

Not applicable. AECOM is not conducting O&M activities.

7.	Have there been opportunities to optimize O&M activities or sampling efforts? Please describe
changes and any resulting or desired cost savings or improved efficiencies.

Not applicable. AECOM is not conducting O&M activities.

8.	Do you have any comments, suggestions or recommendations regarding O&M activities and
schedules at the Site?

Based on the success of the pilot study, full scale I SCO remedy is moving forward with field
implementation expected in 2024.

9.	Do you consent to have your name included along with your responses to this questionnaire in the
FYR report?

Yes

F-4

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SON FORD PRODUCTS SI PERU \D SITE
FIVE-YEAR REVIEW INTERVIEW FORM

Site Name; Sotrford Products

EPA II): IVISD086556388

Interviewer name: Donovan Goibee

Interviewer affiliation: 17PA RPiVl

Subject name;

Subject contact information:

Interview (lore:

Subject affiliation;

Interview time;

Infit \ ir»\ location:

lutervkw format Idnie onv): In Person

Phone Mail

Other:

Interview category: Resident

L Are you aware of the forme/ environmental issues at the Site and the cleanup activities that
have taken place lo date? y€$	\ v joes"

2. What is your overall impression of the project, including cleanup, maintenance and reuse

activities (as appropriate)?

5®



3,	What have been the effects of this Site on. the surra. IMS'*? community, if any? jj f ^

4.	Have (here been any problems wiili unusual or unexpected activities at the Site, such as

emeigcncv response, vandalism or trespassing'1

4/o

5.	I las EPA kept involved parties and surrcmuimg neighbors informed of activities at the Site"'
Row can EPA beat provide site-related information in the future?

6,	Do you own a private well ii> addition 10 or instead of accessing city'municipal water

supplies? If so, for whai purpose(s) is your pmatc we'i used?

A'O

7. Do vou have mi\ comments, suggestions or ;ecomineniiations regarding any aspects of the

project?	,	.

J" j J&-	u_£.o)J	WL

j/J J

4-W. ^>\

x" s<^- H-»«..

sup c

Note: Interview subject is Michael Lacey, owner of Lacey's Digging Services, who currently operates his
business on the site.

F-5

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APPENDIX G - SITE INSPECTION CHECKLIST

FIVE-YEAR REVIEW SITE INSPECTION CHECKLIST



I. SITE INFORMATION

Site Name: Sonford Products

Date of Inspection: April 18. 2023

Location and Region: Flowood, MS Region 4

EPA ID: MSD086556388

Agency, Office or Company Leading the Five-Year
Review: EPA Region 4

Weather/Temoerature: Sunny and 55°F

Remedy Includes: (check all that apply)



[3 Landfill cover/containment

~ Monitored natural attenuation

~ Access controls

~ Groundwater containment

1^ Institutional controls

~ Vertical barrier walls

~ Groundwater pump and treatment



~ Surface water collection and treatment



K1 Other: Excavation of contaminated soil and sediment with on-site consolidation and capping. EPA

changed the remedy and dismantled the lined pile and disposed of it off site at permitted facilities for

hazardous and nonhazardous waste. NAPL extraction with off-site disposal. ISCO is planned for

residual soil, groundwater and NAPL contamination and ISEB for treating downgradient groundwater.

Attachments: [H Inspection team roster attached

PI Site map attached

II. INTERVIEWS (check all that apply)

1. O&M Site Manager



Name

Title Date

Interviewed [~~| at site [~~| at office [~~| bv phone Phone:

Problems, suggestions [~~| Report attached:



2. O&M Staff



Name

Title Date

Interviewed [~~| at site |~~| at office flbv phone Phone:

Problems/suggestions [~~| Report attached:



3. Local Regulatory Authorities and Response Agencies (i.e., state and tribal offices, emergency response

office, police department, office of public health or environmental health, zoning office, recorder of

deeds, or other city and county offices). Fill in all that apply.

Agencv



Contact



Name Title Date Phone

Problems/suggestions PI Report attached:



Agencv



Contact Name



Title Date Phone

Problems/suggestions PI Report attached:



Agencv



Contact



Name Title Date Phone

Problems/suggestions PI Report attached:



Agencv



Contact



Name Title Date Phone

Problems/suggestions P| Report attached:



G-l

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Aeencv
Contact

Name Title
Problems/suggestions [~~| Report attached:

Date

Phone



4.

Other Interviews (optional) HI Report attached:











III. ON-SITE DOCUMENTS AND RECORDS VERIFIED (check all that apply)

1.

O&M Documents









~ O&M manual ~ Readily available

~ Up to date

IXI

N/A



~ As-built drawings ~ Readily available

~ Up to date

m

N/A



~ Maintenance logs ~ Readily available

~ Up to date

IXI

N/A



Remarks: The Site is not vet in the O&M phase.







2.

Site-Specific Health and Safety Plan

~ Readily available

~ Up to date

§N/A



~ Contingency plan/emergency response plan

~ Readily available

~ Up to date

§N/A



Remarks:







3.

O&M and OS HA Training Records
Remarks:

~ Readily available

~ Up to date

M N/A

4.

Permits and Service Agreements









~ Air discharge permit

~ Readily available

~ Up to date

Sn/A



~ Effluent discharge

~ Readily available

~ Up to date

Sn/A



~ Waste disposal. POTW

~ Readily available

~ Up to date

Sn/A



n Other ocrmits:

~ Readily available

~ Up to date

Sn/A



Remarks:







5.

Gas Generation Records
Remarks:

~ Readily available

~ Up to date

Sn/A

6.

Settlement Monument Records
Remarks:

~ Readily available

~ Up to date

Sn/A

7.

Groundwater Monitoring Records
Remarks:

1^ Readily available

E Up to date

~ N/A

8.

Leachate Extraction Records

~ Readily available

~ Up to date

§n/a



Remarks:







9.

Discharge Compliance Records









~ Air ~ Readily available

~ Up to date

IXI

N/A



~ Water (effluent) ~ Readily available

~ Up to date

M

N/A



Remarks:







10.

Daily Access/Security Logs

~ Readily available

~ Up to date

Sn/a

G-2

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Remarks:

IV. O&M COSTS

1. O&M Organization
~ State in-housc
O PRP in-housc
O Federal facility in-housc
^ Site is not vet in the O&M phase

~	Contractor for state
l~l Contractor for PRP

~	Contractor for Federal facility

2.

O&M Cost Records

~ Readily available	~ Up to date

O Funding mechanism/agreement in place O Unavailable
Original O&M cost estimate: __	Breakdown attached

Total annual cost by year for review period if available

From:		To:			

Date

Date

Total cost

From:

To:

Date

Date

Total cost

From:

To:

Date

Date

Total cost

From:

To:

Date

Date

Total cost

From:

To:

~	Breakdown attached
l~l Breakdown attached
l~l Breakdown attached
l~l Breakdown attached

~	Breakdown attached

Date

Date

Total cost

3. Unanticipated or Unusually High O&M Costs during Review Period
Describe costs and reasons:	

V. ACCESS AND INSTITUTIONAL CONTROLS ^ Applicable ~ N/A

A. Fencing

1. Fencing Damaged

Remarks:	

~ Location shown on site map Gates secured ~ N/A

B. Other Access Restrictions

1. Signs and Other Security Measures	~ Location shown on site map

Remarks: No t repassing signs on former stockpile area fence
C. Institutional Controls (ICs)

~ N/A

G-3

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1. Implementation and Enforcement

Site conditions imply Ics not properly implemented	~ Yes ~ No [S3 N/A

Site conditions imply Ics not being fully enforced	~ Yes El No El N/A

Type of monitoring (e.g., self-reporting, drive by):	

Frequency:	

Responsible party/agency:	

Contact 							

Name	Title

Reporting is up to date
Reports arc verified by the lead agency

Specific requirements in deed or decision documents have been met

Violations have been reported

Other problems or suggestions: O Report attached

Date



Phone



O Yes

~

No



N/A

O Yes

~

No



N/A

O Yes

m

No

~

N/A

~ Yes

~

No



N/A

2. Adequacy	~ Ics arc adequate	Ics arc inadequate	~ N/A

Remarks: The EPA intends to implement institutional controls during the second phase of the remedial
action.

D. General

1.	Vandalism/Trespassing ~ Location shown on site map m No vandalism evident
Remarks:	

2.	Land Use Changes On Site	N/A
Remarks:	

3.	Land Use Changes Off Site	N/A
Remarks:	

VI. GENERAL SITE CONDITIONS

A. Roads	Applicable ~ N/A

1. Roads Damaged	~ Location shown on site map Roads adequate ~ N/A

Remarks:	

B. Other Site Conditions

Remarks:

VII. LANDFILL COVERS	~ Applicable ^ N/A

VIII. VERTICAL BARRIER WALLS	~ Applicable ^ N/A

IX. GROUNDWATER/SURFACE WATER REMEDIES [3 Applicable ~ N/A

A. Groundwater Extraction Wells, Pumps and Pipelines	~ Applicable m N/A

1. Pumps, Wellhead Plumbing and Electrical

~ Good condition ~ All required wells properly operating ~ Needs maintenance O N/A

Remarks:	

G-4

-------
2.

Extraction System Pipelines, Valves, Valve Boxes and Other Appurtenances

~ Good condition O Needs maintenance

Remarks:

3.

Spare Parts and Equipment

l~l Readily available O Good condition O Requires upgrade O Needs to be provided
Remarks:

B. Surface Water Collection Structures, Pumps and Pipelines ~ Applicable N/A

1.

Collection Structures, Pumps and Electrical

[~l Good condition ~ Needs maintenance
Remarks:

2.

Surface Water Collection System Pipelines, Valves, Valve Boxes and Other Appurtenances

[~l Good condition ~ Needs maintenance

Remarks:

3.

Spare Parts and Equipment

l~l Readily available O Good condition O Requires upgrade O Needs to be provided

Remarks:

C.

Treatnient System |XI Applicable ~ N/A

1.

Treatnient Train (check components that apply)

[~l Metals removal O Oil/water separation K1 Biorcmediation
~ Air stripping ~ Carbon adsorbers
n Filters:

n Additive (e.g.. chelation agent, flocculent):

K1 Others: NAPL extraction followed bv treatment of residual NAPL using ISCO

l~l Good condition ~ Needs maintenance

l~l Sampling ports properly marked and functional

[~l Sampling/maintenance log displayed and up to date

[~l Equipment properly identified

n Ouantitv of groundwater treated annuallv:

n Ouantitv of surface water treated annuallv:

Remarks: Groundwater treatment with ISCO and ISEB has not vet been implemented.

2.

Electrical Enclosures and Panels (properly rated and functional)

E3 N/A ~ Good condition O Needs maintenance

Remarks:

3.

Tanks, Vaults, Storage Vessels

E3 N/A O Good condition O Proper secondary containment O Needs maintenance

Remarks: Extraction of N APL has been completed and there arc no longer storage tanks as the extracted
NAPL has been disposed off site at a hazardous waste facility.

G-5

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4.

Discharge Structure and Appurtenances

E3 N/A ~ Good condition O Needs maintenance
Remarks:

5.

Treatment BuiWing(s)

1^1 N/A ~ Good condition (esp. roof and doorways) ~ Needs repair

l~l Chemicals and equipment properly stored

Remarks:

6.

Monitoring Wells (pump and treatment remedy)

[~l Properly secured/locked ~ Functioning O Routinely sampled ~ Good condition
[~l All required wells located ~ Needs maintenance £3 N/A
Remarks:

D. Monitoring Data

1.

Monitoring Data

E3 Is routinely submitted on time ~ Is of acceptable quality

2.

Monitoring Data Suggests:

[~l Groundwater plume is effectively contained ~ Contaminant concentrations arc declining

E.

Monitored Natural Attenuation

1.

Monitoring Wells (natural attenuation remedy)

l~l Properly secured/locked O Functioning ~ Routinely sampled Q Good condition
l~l All required wells located O Needs maintenance ^ N/A
Remarks: The monitoring of natural attenuation has not vet been implemented.

X. OTHER REMEDIES

If there arc remedies applied at the site and not covered above, attach an inspection sheet describing the physical
nature and condition of anv facilitv associated with the rcmcdv. An example would be soil vapor extraction.

XI. OVERALL OBSERVATIONS

A.

Implementation of the Remedy

Describe issues and observations relating to whether the remedy is effective and functioning as designed.
Begin with a brief statement of what the remedy is designed to accomplish (e.g., to contain contaminant
plume, minimize infiltration and gas emissions).

Phase 1 of the remedies for OU-1 and OU-2 arc being implemented and pilot testing has begun for the
Phase 2 rcmcdv. The stockpiled excavated soils and sediment were taken off site for disposal at hazardous
and nonhazardous disposal facilities to eliminate exposure to contaminated soil and sediment. The
excavated areas have been restored. NAPL has been extracted to remove contaminant mass from the
subsurface and Phase 2 of residual groundwater, subsurface soil and NAPL contamination is planned to be
treated with ISCO. and downgradient groundwater contamination is planned to be addrssed bv ISEB.

B.

Adequacy of O&M

Describe issues and observations related to the implementation and scope of O&M procedures. In
particular, discuss their relationship to the current and long-term protcctivcness of the remedy.
The Site is not vet in the O&M phase.

C.

Early Indicators of Potential Remedy Problems

Describe issues and observations such as unexpected changes in the cost or scope of O&M or a high

frequency of unscheduled repairs that suggest that the protcctivcness of the remedy may be compromised
in the future.

No issues noted.

D.

Opportunities for Optimization

G-6

-------
Describe possible opportunities for optimization in monitoring tasks or the operation of the remedy.
Phase 2 pilot tests are ongoing and the EPA is evaluating how I SCO can be enhanced prior to full-scale
implementation.

Site Inspection Participants:

Donovan God bee, EPA RPM
Jimmie Crellin, MDEQ project manager
Johnny Zimmerman-Ward, Skeo
Claire Marcussen, Skeo

G-7

-------
APPENDIX H - SITE INSPECTION PHOTOS

Current business office

H-l

-------
Current business operations on the eastern side of the Site

Soil mixing area within sheet pile for the ISCO pilot test

H-2

-------


Former soil stockpile area located within the fenced area

H-3

-------
View of the parcel south of the ISCO test area

Railroad, looking southwest

H-4

-------
JSPEEDi
LIMIT

Payne Drive neighborhood

Municipal supply well in the Payne Drive neighborhood

H-5

-------
APPENDIX I - DETAILED DATA ANALYSIS

Table 1-1: Percent Mass Reduction of PCP from SSCO Pilot Test

Location

Depth
(feet)

Volume
(cubic feet)

Pentachlorophenol (ng/taj)

10/7/2021

4/20/2022

Decrease
fug/kg)

Decrease
(%>

Pre-ISCO Baseline UCL {a}

Post-iSCO UCL (a)

CS-DU-1

0-18

5,400

789,872

C-UCL

103,099

t-UCL

-686,573

86.90%

CS-DU-2

0-6

1,800

117,488

C-UCL

13,308

C-UCL

-104,180

88.70%

C8-DU-3

6-12

1,800

366.269

C-UCL

20.694

C-UCL

-345,574

94.30%

CS-DU-4

12-18

1,800

1,851,502

t-UCL

929,147

C-UCL

-722,355

43.70%

Notes:

	 = 95% Chebyshev Upper Confidence Limit

i I! = incremental Sampling Methodology.
iTR>- = Interstate Technology Regulatory Council.

- 95% Student's t Upper Confidence Limit,
fa} - Calculated using ITRC's ISM Calculator (v. 3.0, August 2020) for Calculating 35% UCL with ISM Data (ITRC 2020).

Source: Phase 2 ISCO Remedial Action: Part 1 - Focused Treatment Areas Summary Report. OU-1 Sonford Superfund Site,
Flowood, MS. Prepared by AECOM for EPA Region 4. December 2022.

I-1

-------
APPENDIX J - DETAILED ARARS REVIEW TABLES

The groundwater cleanup levels identified in the OU-1 2009 ROD (Table 1-1) are based on the federal
MCL established under the Safe Drinking Water Act. In cases where the federal MCL was not available
for a specific groundwater COC, the cleanup goal is the Mississippi Target Remedial Goal (MS TRG)
established in Subpart II of the state Brownfield regulations. In the absence of a MS TRG, a risk-based
value corresponding to a cancer risk of 1 x 10"6or a noncancer HQ equal to 1 was established (Table J-l).
Table J-l shows that the cleanup goals remain valid, as the values remain the same or have become
less stringent, which is the case for 2,3,4,6-tetrachlorophenol and xylenes.

J-l

-------
Table J-l: Review of Cleanup Levels Against Current Standards

coc

Cleanup Level (|ig/L)8

Current Federal Standard

Current State
Standard

Dioxin

Dioxin

0.00003

0.00003

0.00003

Pesticides

Aldrin

0.004

-

0.004

alpha-BHC

0.01

-

0.01

delta-BHC

0.06

-

-

Heptachlor epoxide

0.2

0.2

0.2

SVOCs

2,3,4,6-tetrachlorophenol

110

-

1100

2,4,6-trichlorophenol

6

-

6

2-methylnaphthalene

122

-

122

Isophorone

71

-

71

Naphthalene

6

-

6

PCP

1

1

1

Inorganic Compounds

Iron

11,000

-

11,000

Manganese

730

-

730

VOCs

1,1,1-Trichloroethane

200

200

200

1,2-Dichloropropane

5

5

5

4-Methyl-2-pentanone

139

-

139

Acetone

608

-

608

Benzene

5

5

5

cis-l,2-Dichloroethene

70

70

70

Cyclohexane

26,816

-

-

Ethylbenzene

700

700

700

Isopropylbenzene

679

-

679

Methylcyclohexane

26,816

-

-

Methylene chloride

5

5

5

Total xylenes

7,000d

10,000

10,000

Tetrachloroethene

5

5

5

Toluene

1,000

1,000

1,000

Trichloroethene

5

5

5

Vinyl chloride

2

2

2

Notes:







a. Table 8 of the Site's OU-12009 ROD.





b. EPA MCLs obtained at https://www.epa.gov/ground-water~and-drinking-water/national-prirnarv-drinking"

water-regulations. In November 1991, MDEQ adopted groundwater quality standards equivalent to the

EPA-established drinking water standards or MCLs as per MS MCLs obtained at



https://www.mdea.ms.Hov/wp-content/uploads/2021/05/305b 2021.pdf.



c. MS TRGs obtained at https://www.mdeq.ms.gov/wp-content/uploads/2017/05/Proced.pdf.

d. The ROD recommended EPA's drinking water equivalent level (DWEL) 7000 ng/L for total Xylenes because

the MCL of 10,000 ng/L was determined to not be protective based on the current toxicity assessment on

EPA's Integrated Risk Information System (IRIS).





Hg/L= micrograms per liter







- = standard not established for this COC; cleanup goal was a health-based value.



J-2

-------
APPENDIX K - SCREENING-LEVEL RISK REVIEW

Due to the presence of VOCs in groundwater, this FYR included a screening-level risk evaluation of this
exposure pathway using the EPA's 2023 Vapor Intrusion Screening Level (VISL) calculator. The EPA's
RSL calculator was also used to evaluate if the site cleanup goals for soil and surface water remain valid
based on changes in toxicity values or default exposure assumptions. In addition, the EPA collected
surface soil samples at properties south and east of the former Sonford facility parcel to further
delineate site COCs. The RSL calculator was also used to screen these data to determine if there were
locations that exceeded outdoor worker health-based levels. Sediment cleanup goals were established
for wet sediments, which were based on ecological exposure and ecological risk guidance has not had
significant changes since the ROD was issued. Human exposure to wet sediments is considered
incomplete as the water would wash off sediments from the surface of the skin.

Vapor Intrusion

The VISL calculator is an empirical model that predicts indoor air concentrations from groundwater
concentrations using conservative "generic" attenuation factors and current toxicity information.

These factors reflect worst-case conditions and do not consider any site-specific conditions such as site
soil strata, depth to water table or building properties that may reduce the transport of vapors from
groundwater through the soil column.

Groundwater data from this FYR period were used to evaluate if the vapor intrusion exposure pathway
requires further evaluation. To provide a conservative vapor intrusion evaluation, the maximum-
detected COC concentrations from the monitoring wells in the shallow groundwater zone in the Payne
Drive neighborhood entered into the EPA's VISL calculator. The maximum concentrations for the
volatile site COCs were observed in SP177S. The shallow zone is used because this contamination
would be closest to the foundation of an existing building.

As shown in Table K-l, the cumulative cancer risks as represented by SP177S, are within the EPA's
acceptable risk range of 1 x 10"4 to 1 x 10"6. The individual noncancer HQs are equal to or below the
EPA threshold of 1. Based on cumulative HQs, the total hazard index does not exceed 1. This finding,
together with the knowledge that these contaminants do not all have the same target organ for
toxicity, suggests that the vapor intrusion pathway is not of concern, i.e., vapor intrusion is not a
completed exposure pathway.

K-l

-------
Table K-l: Screening-Level Vapor Intrusion Evaluation



2021 Concentration

Vapor Intrusion Risk Characterization for

coc

for SP177S

Residential Use



(ms/l)3

Risk

Noncancer HQ

Dioxin

SVOCs

2-Methylnaphthalene

34

-

-

Naphthalene

56

1.22 x 10 s

0.3

VOCs

1,2-Dichloropropane

5.2

7.97 x 10 7

0.1

4-Methyl-2-pentanone

32

-

0.00006

Benzene

45

2.84 x 10 s

0.3

Ethylbenzene

43

1.23 x 10 s

0.01

Isopropylbenzene

18

-

0.02

Total xylenes

120

-

0.3

Toluene

8.4

-

0.0004

Vinyl chloride

4.3

2.92 x 10 s

0.05

Cumulative

8.89 x 10 s

1

Notes:







a. Data obtained from well SP177S, sampled in 2021.





Nv = not volatile







Hg/L = micrograms per liter







HQ = hazard quotient







MCL= maximum contaminant level (July 2002).





Bold italic = noncancer HQ exceed the threshold of 1.





Source: Sonford Products 2021 Sampling Report. Flowood, Mississippi. Prepared by Laboratory Services and

Applied Science Division. EPA Region 4. October 2021.





Surface Soil

A screening-level risk evaluation was conducted on the 2010 OU-2 on-site surface soil cleanup goals to
determine if the goals remain valid since toxicity values have changed for several COCs. Using the EPA's
RSL calculator, the cleanup goals were determined to be equivalent to a cancer risk within the EPA's
risk management range of 1 x 10~6 to 1 x 10"4 and equal to a noncancer HQ of 1 (based on one
significant figure) (Table K-2). A similar analysis was conducted for the off-site surface soil cleanup goal
for dioxin based on a residential exposure (Table K-3). The off-site residential exposure evaluation
shows that the cleanup goal is equivalent to a cancer risk within the EPA's risk management range and
slightly exceeds the HQ of 1 based on one significant figure. However, dioxin TEQ data from the highest
residential confirmation sample shows that the residential cleanup resulted in cancer risks within the
EPA's risk management range and does not exceed the HQ of 1. Following the 2012 excavations in the
neighborhood the EPA restored the excavated properties, including sod installation, and replacement
of trees, bushes and fencing where necessary.

K-2

-------
Table K-2: Screening-Level Risk Evaluation of On-Site Surface Soil Cleanup Goals



On-Site Surface Soil









coc

OU-2 ROD Cleanup
Goal

Industrial RSL8 (mg/kg)

Risk"

HQC



(Hg/kg)

(mg/kg)

IQ"6 Risk

t—;

El

a

X





Dioxin (TCDD-TEQ) - Onsite

1

0.001

2.2 x 10 s

7.2 xlO 4

5 x 10 s

1 (1-4)

PCP

23,800

23.8

4

2800

6 x 106

0.009

Gamma-BHC

4,400

4.4

2.5

300

2 x 106

0.02

Alpha-BHC

908

0.908

0.36

-

3 x 106

-

Delta-BHC

3,180

3.18

NA

-

-

-

Aldrin

377

0.4

0.18

35

2 x 106

0.01

DDE

16,800

16.8

9.3

580

2 x 106

0.03

DDT

16,800

16.8

8.5

520

2 x 106

0.03

Dieldrin

358

0.358

0.14

41

3 x 106

0.009

Mercury (as mercury chloride)

61,300

61.3

NA

350

-

0.2

Notes:













a. Current EPA RSLs, dated May 2023, are available at https://www.epa.gov/risk/regional-screening-levels-rsls-

generic-tables (accessed 6/5/2023).













b. The cancer risks were calculated using the following equation, based on the fact that RSLs are derived based on 1

x 106 risk: cancer risk = (cleanup goal

t- cancer-based RSL) x 106.









c. The noncancer HQ was calculated using the following equation:

HQ= (cleanup goal -f noncancer RSL).



NA = not applicable, as the EPA has not classified this COC as a carcinogen.







- = a toxicity value has not been established for this compound.









Mg/kg = milligrams per kilogram













Table K-3: Screening-Level Risk Evaluation of Off-Site Dioxin Surface Soil Cleanup Goal

COC

Off-Site Surface Soil OU-2
ROD Cleanup Goal

Residential RSL3

Riskb

HQC

(Hg/kg)

(mg/kg)

10"6 Risk

HQ = 1.0

Dioxin (TCDD-TEQ) (surface soil)

0.078

0.000078

4.8 x 106

5.1 x 10 s

2 x 10 s

(1.5)2

Dioxin (TCDD TEQ)

(maximum confirmation data)d

0.049

0.000049

4.8 x 10 6

5.1 x 10 s

1 x 10 s

1

Notes:

a.	Current EPA RSLs, dated May 2023, are available at https://www.epa.gov/risk/regional-screening-levels-rsls~
generic-tables (accessed 6/5/2023).

b.	The cancer risks were calculated using the following equation, based on the fact that RSLs are derived based on
1 x 106 risk: cancer risk = (cleanup goal -f cancer-based RSL) x 106.

c.	The noncancer HQ was calculated using the following equation: HQ = (cleanup goal -f noncancer RSL).

d.	Maximum confirmation result obtained from Section 4.7 of the 2012 OU-2 Phase I Remedial Action Report.

Bold value = noncancer HQ exceeds 1.

Mg/kg = milligrams per kilogram	

In 2019, the EPA completed additional surface soil sampling to the south and east of the former
Sonford facility. A screening-level risk evaluation of the maximum concentration of site COCs detected
in 2019 shows that only dioxin is equal to or exceeds noncancer threshold HQ of l1 at four locations
immediately east of the former Sonford facility (Table K-4) based on a default composite worker (on-
site worker that spends most of the workday conducting maintenance activities outdoors). The cancer
risks were within the EPA's risk management range of 1 x 10~6 to 1 x 10~4 based on the sum of the

1SP347, SP348 and SP346 were within EPA's risk range and equal to or to and HQ of 1.

K-3

-------
maximum concentration risk of each COC. Due to exceedances of the ROD cleanup goal for dioxin in
SP343, the EPA collected three composite samples further east (SP356, SP357 and SP358) in 2021. The
maximum composite concentration from location SP356 was equivalent to a cancer risk of 2 x 10~5
which is within the EPA's risk management range and below an HQ of 1 (HQ=0.7). The EPA is in the
process of finalizing a sampling plan to complete further delineation to determine if any further actions
are warranted for surface soil.

Table K-4: Screening-Level Risk Evaluation of Surface Soil Samples, 2019

COC

Maximum 2019

Composite Worker®

Detection (mg/kg)

Risk

HQ

Aldrin

<0.0022

1 x 10 s

0.00006

DDE

0.001(SP347)

1 x 101CI

1.7E-06

DDT

0.00079(SP347)

9 x 10n

1.5E-06

Dieldrin

<0.0044

3 x 10 s

0.0001

Dioxin (TCDD-TEQ)

0.0014 (SP343)

7 x 10 s

2



0.00052 (SP356)b

2 x 10 s

0.7

Alpha-BHC

0.00065(SP351)

2 x 109

-

Delta-BHC

0.0085(SP351)

NA

-

Gamma-BHC

0.0034(SP351)

1 x 109

0.00001

PCP

0.310 (SP352)

8 x 10 s

0.0001

Notes:







a. Risk calculated using the EPA's RSL calculator and default assumptions for a composite worker, available at

https://epa-prgs.ornl.gov/cgi-bin/chemicals/csl search.





b. Maximum detected concentration in composite sampled collected in 2021.



Bold = noncancer HQ exceeds 1.







Mg/kg = milligrams per kilogram







NA = not applicable, as the EPA has not classified this COC as a carcinogen.





Sources: Sonford Products 2019 Sampling Report. Flowood, Mississippi. Tables 6 though 8. Prepared by Laboratory

Services and Applied Science Division. EPA Region 4. September 2019. Sonford Products 2021 Sampling Report.

Flowood, Mississippi. Table 6. Prepared by Laboratory Services and Applied Science Division. EPA Region 4.

October 2021.







Groundwater

A screening-level risk evaluation of the health-based groundwater cleanup goals was conducted to
determine if the cleanup goals for COCs without established MCLs and TRGs remain valid for delta-
BHC, cyclohexane, methylcyclohexane and total xylenes. Using the EPA's RSL calculator, the cleanup
goals for cyclohexane and total xylenes were determined exceed a noncancer HQ of 1 (based on one
significant figure).

However, cyclohexane did not exceed the current RSL, nor the ROD Cleanup Level, during the
groundwater sampling events in 2019 and 2021. Well SP171 was the only groundwater monitoring well
that exceeded the generic Tap Water RSL for Total Xylenes in the 2019 and 2021 sampling events. The
current ROD Cleanup Level for Total Xylenes was not exceeded in this sample data however, and
generic RSL's are only a preliminary screening level that are generally used prior to completing a
Human Health Risk Assessment and Site ROD. The EPA will evaluate amending the ROD to change the
cleanup level for total xylenes based on consideration of inhalation exposure to volatilized Xylenes.

K-4

-------
Table K-5: Screening-Level Risk Evaluation of Health-based Groundwater Cleanup Goals

COC

GU-1 ROD Cleanup Goal

Tap Water RSL"

Riskb

HQC

(W?/L)

10"6 Risk

1!

a

rr

Delta-BHC

0.06

NA

-

-

-

Cyclohexane

26,816

NA

12,500

-

2

Methylcyclohexane

26,816

NA

-

-

-

Total Xylenes

7,000

NA

193d

-

36

Notes:

a. Current EPA RSLs, dated May 2023, are available at https://www.epa.gov/risk/regional-screening-levels-rsls-

generic-tables (accessed 10/16/2023).

b.	The cancer risks were calculated using the following equation, based on the fact that RSLs are derived based on 1
x 106 risk: cancer risk = (cleanup goal -f cancer-based RSL) x 106.

c.	The noncancer HQ was calculated using the following equation: HQ = (cleanup goal -f noncancer RSL).

d.	The current Regional Screening Level (RSL) for Xylenes in tap water is 193 ng/L. However, since this RSL is based
on a child-only exposure that is overprotective for a typical residential drinking water scenario, a site-specific
value can be derived using the RSL calculator. Using a volatilization factor of 0.13 L/m3 (based on the Region 4
guidance or exposure to VOCs via showering) and an age-weighted ingestion rate of 2.1 L/d and body weight of
65 kg, results in a health protective level for xylenes in groundwater of 670 ng/L.

NA = not applicable, as the EPA has not classified this COC as a carcinogen.

- = a toxicity value has not been established for this compound,
mg/kg = milligrams per kilogram

Surface water

A sites-specific risk assessment addendum was conducted by the EPA in 2010 to establish cleanup
goals for surface water based on nearby residents that occasionally visit the nearby drainage ditch.
Entering the exposure factors used in the 2010 risk assessment addendum the cleanup goals remain
valid as the risk are within the EPA's risk management range and the HQs are equal to or less than 1
(Table K-6).

Table K-6: Screening-level Risk Evaluation of the OU-2 Surface Water Cleanup Goals

COC

Surface Water OU-2 Cleanup



Residential Exposure"



Goal (ng/L)









Off-Site"

Lifetime
Risk

Adult HQ

Child HQ

Dioxin (TCDD-TEQ)

0.001

2 x 107

0.001

0.002

Gamma-BHC

0.08

1 x 10 s

0.05

1

Notes:









a. Exposure assumptions were obtained from Table A-4.1 of the 2010 Baseline Human Health Risk

Assessment Addendum, August.







Hg/L = micrograms per liter









K-5

-------