United States
Environmental Protection Agency 1200 Pennsylvania Avenue, N.W. Washington, D.C. 20460 March 2011

Office of Solid Waste and Emer g enc y Res p onse



# Support Document for the
Revised National Priorities List Final Rule – Wright Chemical Corporation

# Support Document for the
Revised National Priorities List
Final Rule Wright Chemical Corporation

March 2011

Site Assessment and Reme dy Decisions Branch Office of Superfund Remediati on and Technology Innovation Office of Solid Waste and Emergency Response U.S. Environmental Protection Agency Washington, DC 20460Wright Chemical Corporation NPL Listing Support Document March 2011



### Table of Contents

Executive Summary

............................................................................................................................... ....iii

Introduction ................................................................................................................................................iv

Background of the NPL ...........................................................................................................................iv

Development of the NPL ..........................................................................................................................v

Hazard Ranking System ...........................................................................................................................v

Other Mechanisms for Listing .................................................................................................................vi

Organization of this Document ...............................................................................................................vii

Glossary ..................................................................................................................................................vii

1. List of Commenters and Correspondence ........................................................................................1

2. Site Description ...................................................................................................................................1

3. Summary of Comments .....................................................................................................................2

3.1 Support for Listing........................................................................................................................2

3.3 Need for Remediation ...................................................................................................................5

3.4 Incomplete Exposure Route/No Risk ............................................................................................6

3.5 Oak-Bark/Hexion Facility - No Further Effort Needed ................................................................6

3.6 Deferral to Other Programs ...........................................................................................................6

3.7 Description of In-Water Segment .................................................................................................7

3.8 Observed Release to Livingston Creek – Significant Increase .....................................................8

3.9 Observed Release by Chemical Analysis - Attribution ...............................................................10

3.9.1 Association with Site Source .............................................................................................................14
3.9.2 Other Facilities

............................................................................................................................... ...15

3.10 Waste Characteristics ..................................................................................................................18

3.10.1 Waste Quantity

............................................................................................................................... ...18
3.10.2 Eligible Hazardous Substances ..........................................................................................................20
3.10.3 Assignment of Bioaccumu lation Factor Values ................................................................................22
3.10.4 Containment

............................................................................................................................... .......24

3.11 Targets

............................................................................................................................... ..........25

iWright Chemical Corporation Comment Summary 9/30/2010

ii 3.11.1 Presence of Private Receptors ...........................................................................................................25
3.11.2 Zone of Contamination ......................................................................................................................26

4. Conclusion

............................................................................................................................... ..........28Wright Chemical Corporation NPL Listing Support Document March 2011



## Executive Summary

Section 105(a)(8)(B) of CERCLA, as amended by SARA, requires that the EPA prepare a list of national priorities among the known releases or threatened re leases of hazardous substances, pollutants, or contaminants throughout the United States. An orig inal National Priorities List (NPL) was promulgated on September 8, 1983 (48 FR 40658). CERCLA requir es that EPA update the list at least annually.

This document provides responses to public comments received on the Wright Chemical Corporation site, proposed on March 4, 2010 (75 FR 9843). This site is being added to the NPL based on an evaluation under EPA’s Hazard Ranking System (HRS) in a final rule published in the Federal Register in March

2011.

iiiWright Chemical Corporation Listing Support Document March 2011



## Introduction

This document explains the rationale for adding the Wright Chemical Corporation site in Riegelwood, North Carolina, to the National Priorities List (NPL) of uncontrolled hazardous waste sites and provides responses to public comments received on this site lis ting proposal. The EPA proposed this site to the NPL on March 4, 2010 (75 FR 9843). This site is be ing added to the NPL based on an evaluation under the Hazard Ranking System (HRS) in a final rule published in the Federal Register in March 2011.



### Background of the NPL

In 1980, Congress enacted the Comprehensive Enviro nmental Response, Compensation, and Liability Act (CERCLA), 42 U.S.C. Sections 9601 et seq . in response to the dangers of uncontrolled hazardous waste sites. CERCLA was amended on October 17, 1986, by the Superfund Amendments and Reauthorization Act (SARA), Public Law No. 99-499, stat., 1613 et seq. To implement CERCLA, EPA promulgated the
revised National Oil and Hazardous Substances Polluti on Contingency Plan (NCP), 40 CFR Part 300, on July 16, 1982 (47 FR 31180), pursuant to CERCLA Section 105 and Executive Order 12316 (46 FR 42237, August 20, 1981). The NCP, further revised by EPA on September 16, 1985 (50 FR 37624) and November 20, 1985 (50 FR 47912), sets forth guid elines and procedures needed to respond under
CERCLA to releases and threatened releases of hazard ous substances, pollutants, or contaminants. On March 8, 1990 (55 FR 8666), EPA further revised the NCP in response to SARA.

Section 105(a)(8)(A) of CERCLA, as amended by SARA, requires that the NCP include

criteria for determining priorities among rel eases or threatened releases throughout the United States for the purpose of taking remedial action and, to the extent practicable, take into account the potential urgency of such action, for the purpose of taking removal
action.

Removal action involves cleanup or other actions that are taken in response to emergency conditions or on a short-term or temporary basis (CERCLA Section 101). Remedial action is generally long-term in nature and involves response actions that are consistent with a permanent remedy for a release (CERCLA Section 101). Criteria for placing sites on the NPL, which makes them eligible for remedial actions financed by the Trust Fund established under CERCLA, were included in the HRS. EPA promulgated the HRS as Appendix A of the NCP (47 FR 31219, July 16, 1982). On December 14, 1990 (56 FR 51532), EPA promulgated revisions to the HRS in response to SARA, and established the effective date for the HRS revisions as March 15, 1991.

Section 105(a)(8)(B) of CERCLA, as amended, requires that the statutory criteria provided by the HRS be used to prepare a list of national priorities among th e known releases or threatened releases of hazardous substances, pollutants, or contaminants throughout th e United States. The list, which is Appendix B of the NCP, is the NPL.

An original NPL of 406 sites was promulgated on September 8, 1983 (48 FR 40658). At that time, an
HRS score of 28.5 was established as the cutoff for lis ting because it yielded an initial NPL of at least 400 sites, as suggested by CERCLA. The NPL has been expanded several times since then, most recently on September 29, 2010 (75 FR 59975). The Agency al so has published a number of proposed rulemakings to add sites to the NPL. The most recent proposal was on October 21, 2010 (75 FR 64976).

ivWright Chemical Corporation Listing Support Document March 2011



### Development of the NPL

The primary purpose of the NPL is stated in the le gislative history of CERCLA (Report of the Committee on Environment and Public Works, Senate Repor t No. 96-848, 96th Cong., 2d Sess. 60 [1980]).

The priority list serves primarily informa tional purposes, identifying for the States and the public those facilities and sites or other releases which appear to warrant remedial actions. Inclusion of a facility or site on the list does not in itself reflect a judgment of the activities of its owner or operator, it does not require those persons to undertake any action, nor does it assign liability to any person. Subsequent govern ment actions will be necessary in order to do so, and these acti ons will be attended by all appropriate procedural safeguards.

The NPL, therefore, is primarily an informational a nd management tool. The identification of a site for the NPL is intended primarily to guide EPA in determ ining which sites warrant further investigation to
assess the nature and extent of the human health and environmental risks associated with the site and to determine what CERCLA-financed remedial action(s), if any, may be appropriate. The NPL also serves to notify the public of sites EPA believes warrant further investigation. Finally, listing a site may, to the extent potentially responsible parties are identifiable at the time of listing, serve as notice to such parties that the Agency may initiate CERCLA-financed remedial action.

CERCLA Section 105(a)(8)(B) directs EPA to list prio rity sites among the known releases or threatened release of hazardous substances, pollutants, or c ontaminants, and Section 105(a)(8)(A) directs EPA to consider certain enumerated and other appropriate factors in doing so. Thus, as a matter of policy, EPA has the discretion not to use CERCLA to respond to cer tain types of releases. Where other authorities exist, placing sites on the NPL for possible remedial action under CERCLA may not be appropriate. Therefore, EPA has chosen not to place certain types of sites on the NPL even though CERCLA does not exclude such action. If, however, the Agency later determines that sites not listed as a matter of policy are not being properly responded to, the Agency may consider placing them on the NPL.



### Hazard Ranking System

The HRS is the principle mechanism EPA uses to place uncontrolled waste sites on the NPL. It is a numerically based screening system that uses inform ation from initial, limited investigations -- the preliminary assessment and site inspection -- to assess th e relative potential of sites to pose a threat to human health or the environment. HRS scores, however, do not determine the sequence in which EPA funds remedial response actions, because the inform ation collected to develop HRS scores is not
sufficient in itself to determine either the extent of contamination or the appropriate response for a particular site. Moreover, the sites with the hi ghest scores do not necessarily come to the Agency's attention first, so that addressing sites strictly on the basis of ranking would in some cases require stopping work at sites where it was already underway. Thus, EPA relies on further, more detailed studies in the remedial investigation/feasibilit y study that typically follows listing.

The HRS uses a structured value analysis approach to scoring sites. This approach assigns numerical values to factors that relate to or indicate risk, b ased on conditions at the site. The factors are grouped into three categories. Each category has a maximum value. The categories are:

• likelihood that a site has released or has the potential to release hazardous substances into the environment;

vWright Chemical Corporation Listing Support Document March 2011

• characteristics of the waste (toxicity and waste quantity); and

• people or sensitive environments (targets) affected by the release.

Under the HRS, four pathways can be scored for one or more threats as identified below:

• Ground Water Migration (S gw ) - drinking water

• Surface Water Migration (S

sw ) The following threats are evaluated for two separate migration components, overland/flood migration and ground water to surface water. - drinking water
- human food chain
- sensitive environments

• Soil Exposure (S

s ) - resident population - nearby population
- sensitive environments

• Air Migration (S

a ) - population
- sensitive environments

After scores are calculated for one or more pathways according to prescrib ed guidelines, they are combined using the following root-mean-square equati on to determine the overall site score (S), which ranges from 0 to 100 :



### 4 S + S + S + S = S 2

a 2

s 2

sw 2

gw

If all pathway scores are low, the HRS score is low. However, the HRS score can be relatively high even if only one pathway score is high. This is an important requirement for HRS scoring because some extremely dangerous sites pose threats through only one pathway. For example, buried leaking drums of hazardous substances can contaminate drinking water wells, but -- if the drums are buried deep enough and the substances not very volatile -- not surface water or air.



### Other Mechanisms for Listing

There are two mechanisms other than the HRS by whic h sites can be placed on the NPL. The first of these mechanisms, authorized by the NCP at 40 CFR 300. 425(c)(2), allows each State and Territory to designate one site as its highest priority regardless of score. The last mechanism, authorized by the NCP at 40 CFR 300.425(c)(3), allows listing a site if it meets the following three requirements:

• Agency for Toxic Substances and Disease Registry (ATSDR) of the U.S. Public Health Service has issued a health advisory that recommends dissociation of individuals from the release;

• EPA determines the site poses a significant threat to public health; and

viWright Chemical Corporation Listing Support Document March 2011

• EPA anticipates it will be more cost-effective to use its remedial authority than to use its emergency removal authority to respond to the site.



### Organization of this Document

The following section contains EPA responses to s ite-specific public comments received on the proposal of the Wright Chemical Corporation site on March 4, 2010 (75 FR 9843). The site discussion begins with a list of commenters, followed by a site description, a summary of comments, and Agency responses to each comment. A concluding statement indicates the effect of the comments on the HRS score for the
site.



### Glossary

The following acronyms and abbreviations are used throughout the text:

Agency U.S. Environmental Protection Agency

BPFV Bioaccumulation Potential Factor Value

CAP Corrective action plan

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act of 1980, 42 U.S.C. Sections 9601 et seq ., also known as Superfund

CFR Code of Federal Regulations

CRQL Contract-required quantitation limit

CSA Comprehensive site assessment

DL Detection limit

EE/CA Engineering evaluation and cost analysis

EPA U.S. Environmental Protection Agency

ESI Expanded site inspection

FR Federal Register

HRS Hazard Ranking System, Appendix A of the NCP

HRS score Overall site score calculated using the HRS; score ranges from 0 to 100

MDL Method detection limit

mg/kg Milligram per kilogram

MRL Minimum reporting limit

NCDENR North Carolina Department of E nvironment and Natural Resources

NCP National Oil and Hazardous Substances Po llution Contingency Plan, 40 C.F.R.

Part 300

NOAA National Oceanic and Atmospheric Administration

NPL National Priorities List, Appendix B of the NCP

NTCRA Non-time critical removal action

PEL Probable effects level

viiWright Chemical Corporation Listing Support Document March 2011

viii PPE Probable point of entry

PRP Potentially responsible party

RCRA Resource Conservation and Recovery Act

RI/FS Remedial investigation and feasibility study

ROD Record of Decision

SARA Superfund Amendments and Reauthorization Act

SOP Standard operating procedure

SQL Sample quantitation limit

T/P/BPFV Toxicity/persistence/bioaccumulation potential factor value

TCRA Time critical removal action

TDL Target distance limitWright Chemical Corporation NPL Listing Support Document March 2011



## 1. List of Commenters and Correspondence

EPA-HQ-SFUND-2010-073-0003 Correspondence, dated December 9 2009, from Dee Freeman, Secretary, North Carolina Department of Environment and Natural Resources, letter requesting placement of the Wright Chemical Corporation site on the National Priorities List (NPL)

EPA-HQ-SFUND-2010-073-0007 Comment, da ted May 3, 2010, from John A. Andeason, McGrath North, Mullen & Kratz, PC LLO on behalf of Oak-Bark Corporation

EPA-HQ-SFUND-2010-073-0007.1 Comment a ttachment, dated May 3, 2010, from John A. Andeason, McGrath North, Mullen & Kratz, PC LLO on behalf of Oak-Bark Corporation

EPA-HQ-SFUND-2010-073-0007.2 Comment attachment, dated May 3, 2010, from John A. Andeason, McGrath North, Mullen & Kratz, PC LLO on behalf of Oak-Bark Corporation r

EPA-HQ-SFUND-2010-073-0007.3 Comment a ttachment, dated May 3, 2010, from John A. Andeason, McGrath North, Mullen & Kratz, PC LLO on behalf of Oak-Bark Corporation

EPA-HQ-SFUND-2010-073-0007.4 Comment a ttachment, dated May 3, 2010, from John A. Andeason, McGrath North, Mullen & Kratz, PC LLO on behalf of Oak-Bark Corporation

EPA-HQ-SFUND-2010-073-0007.5 Comment a ttachment, dated May 3, 2010, from John A. Andeason, McGrath North, Mullen & Kratz, PC LLO on behalf of Oak-Bark Corporation

EPA-HQ-SFUND-2010-073-0007.6 Comment a ttachment, dated May 3, 2010, from John A. Andeason, McGrath North, Mullen & Kratz, PC LLO on behalf of Oak-Bark Corporation



## 2. Site Description

The Wright Chemical Corporation site (the Site; the Wr ight Chemical site) is located in an industrial/rural area of Riegelwood, Columbus County, North Caro lina, adjacent to tidal wetlands along Livingston Creek. Livingston Creek is a tributary of the Cape Fear River. The Site consists of contaminated soil and
a release of contaminants to sedim ent within Livingston Creek. The contaminated soil is the result of
waste materials from a former lead chamber sulfur ic acid manufacturing plant being deposited into a wetland area contiguous to Livingston Creek. Th e observed release to surface water is based on
contaminants associated with the waste material detect ed in Livingston Creek sediments at concentrations significantly greater than in background sediment sa mples. Observed release contaminants include lead, arsenic, cadmium, copper, and zinc. Livingston Creek is a freshwater body in the area of the Site; however, there are portions of the target distance limi t (TDL) downstream that are saltwater/brackish. In the area of the Site, Livingston Creek is under tidal in fluence. In the area of the release from Wright

1Wright Chemical Corporation Listing Support Document March 2011

Chemical, Livingston Creek is a human food chain fishery. Figure 1 of this support document provides the Site location information with respect to neighboring facilities.



## 3. Summary of Comments

John A. Andreasen submitted comments on behalf of McGrath North, which represents the Oak-Bark Corporation of Wilmington, North Carolina. McGr ath North opposed listing the Site on the NPL, and specifically submitted comments directed at the Site location, site size, the minimal potential private receptors to the surrounding community and/or envi ronment, and the viability of other State and/or Federal programs.

McGrath North stated that the Site is located i mmediately adjacent to a freshwater swamp which is influenced by Livingston Creek and that there are three other current/former facilities/sites that are upgradient from the Site. McGrath North raised sever al issues identifying other facilities that could be possible sources of the contamination in Livingsto n Creek, particularly when tidal influence is considered. McGrath North asserted that any connection of the Wright Chemical site to Livingston Creek is an incomplete chain and attribution of the Wright Chemical site is not complete.

McGrath North questioned the size and definition of th e Wright Chemical site as described in the HRS documentation record at proposal and asserted that the Site has been misconstrued as being much larger than it actually is. McGrath North questioned the presen ce of targets in the vicinity and stated that there are no potential private receptors that could be affected by releases at the Wright Chemical site and
further stated that there has been no significant increase of contaminant concentrations in water samples from Livingston Creek.

McGrath North questioned the need for remediation at th is site, stating that it is agreed that arsenic and lead contaminated soils should be prevented from mi grating off site; however, the present situation is stable and a cleanup is not time critical. McGrath North questioned the appropriateness of listing the Wright Chemical site on the NPL, stating that there are at least two other State and/or Federal programs that would be more appropriate for addressing the S ite. McGrath North finally stated that Oak-Bark Corporation does not believe that the Site poses a significant threat to public health, welfare, or the
environment.



### 3.1 Support for Listing

Comment: The State of North Carolina submitted a gover nor's letter (dated December 9, 2009) to the EPA Region 4 Administrator stating that the State ag rees that the Site poses a significant threat to the public health and the environment and supports EPA's efforts to propose the Site for inclusion on the

NPL.

Response : The Wright Chemical site has been added to the NPL. Listing makes a site eligible for remedial actions under CERCLA, and EPA will examine th e Site to determine what response, if any, is appropriate. Actual funding may not necessarily be undertaken in the precise order of HRS scores, however, and upon more detailed inv estigation may not be necessary at all in some cases. EPA will determine the need for Superfund monies for remedi al activities on a site-by-site basis, taking into account the NPL ranking, State priorities, further site investigation, other response alternatives, and other factors as appropriate. EPA will not stop work at so me sites to begin work at other higher-scoring sites added to the NPL more recently.

2Figure 1: Livingston Creek and Cape Fear RiverSite: Wright Chemical Corp.NCD 024 766719Date: 05/21/08; rev. 12/09/09Columbus Co., NCDrawn By: JSSAerial Photo Date: 2004

C a p e F e a r Ri v e rLCV2LCV (pre-2005)~ 1⁄2 mile M i l l C r e e kSee Ref. 7 of HRS Doc Record for figure source information

L i v i n g s t o n C r ee k

L i v i n g s t o n C r e e kWright ChemicalHexionHoltrachemInternational PaperKaiser AgriculturalKaiserAcme FarmarketWright Chemical Corporation Listing Support Document March 2011

3.2 Site Description/Definition of Site

Comment: McGrath North questioned the size and definition of the Site as described in the HRS documentation record at proposal. McGrath North asserted that the Site has been misconstrued as being much larger than it actually is. McGrath North stat ed that the former sulfuric acid facility is only approximately one acre in size and that the contamination from this source has been spread to a larger area including a slope leading to a freshwater swamp. McGrath North stated that the approximate extent of the known contaminated area is only 6 acres. McGrath North attached a figure (Figure 3 - Approximate Area of Contamination, prepared by Shields Engineering Inc., April 2010) delineating an approximate 6-acre area of contamination. McGrath North noted that this is a significantly smaller area than the 80 acres designated in the HRS documentation record. McGrath North further stated, "As can be seen on Figure 3, the probable extent of the magent a contamination can be fairly readily seen. This contamination does not appear to be migrating to the surrounding community."

Response: While the property on which the Wright Chemical facility is located is 80 acres in size, the Wright Chemical site is not defined by the pr operty boundaries. It is defined by the area of contamination. The HRS documentation record at pr oposal described both the Wright Chemical facility property and the Wright Chemical site area. The HRS documentation record at proposal stated on page 15 that the Wright Chemical facility includes an area of magenta-colored soil that is primarily located on two parcels that total about 80 acres. The Wright Chemical site for HRS evaluation purposes includes the contaminated soil from the three subareas of Source 1 described on pages 15-16 of the HRS documentation record at proposal, as well as the c ontaminated sediments in Livingston Creek as described on page 30 of the HRS documentation record at proposal.

The extent of a site and its boundaries are not define d at the time of listing. Rather, placing a site on the NPL is based on an evaluation, in accordance with the HRS, of a release or threatened release of hazardous substances, pollutants, or contaminants. Th e fact that EPA initially identifies and lists the release based on a review of contamination at a certain parcel of property does not necessarily mean that the site boundaries are limited to that parcel.

CERCLA Section 105(a)(8)(A) requires EPA to lis t national priorities among the known “releases or threatened releases” of hazardous substances; thus, the focus is on the release, not precisely delineated boundaries. Further, CERCLA Section 101(a) defi nes a “facility” as the “site” where a hazardous substance has been “deposited, stored, placed, or ot herwise come to be located.” The “come to be located” language gives EPA broad authority to clean up contamination when it has spread from the original source.

The revised HRS (55 FR 51587, December 14, 1990) elaborates on the “come to be located” language, defining “site” as “area(s) where a hazardous substance has been deposited, stored, disposed, or placed, or
has otherwise come to be located. Such areas ma y include multiple sources, and may include the area
between the sources.”

On April 9, 2009 (74 FR 16165), EPA stated:

The NPL does not describe releases in precise geographical terms; it would be neither feasible nor consistent with the limited purpo se of the NPL (to identify releases that are priorities for further evaluation), for it to do so. . . . [T]he HRS inquiry focuses on an evaluation of the threat posed and therefor e the boundaries of the release need not be exactly defined. Moreover, it generally is im possible to discover the full extent of where the contamination ‘has come to located’ before all necessary studies and remedial work are completed at a site. . . .During the RI/ FS [remedial investigation/feasibility study]

4Wright Chemical Corporation Listing Support Document March 2011

process, the release may be found to be larger or smaller than was originally thought, as more is learned about the source(s) and the migration of the contamination. . . . [T]he known boundaries of the contamination can be expected to change over time.

Until the site investigation process has been complete d and a remedial action (if any) selected, EPA can neither estimate the extent of contamination at the site, nor describe the ultimate dimensions of the NPL site. Even during a remedial action EPA may find that the contamination has spread further than previously estimated. In addition, if another, unrel ated area of contamination is discovered elsewhere on the property, EPA may decide to evaluate that release for the NPL.

Regarding the visual observations made on Figure 3 in the HRS documentation record at proposal, McGrath North stated that the magenta-colored staining appears to be localized. This statement does not mean the contamination, or the Site, is limited to the stained area (see section 3.10.1 of this support document for additional waste quantity information), In fact, the analytical results from sediment samples collected from Livingston Creek in April 2007 indicate that contaminants associated with the evaluated site source (i.e., contaminated soil) are migrating to Livingston Creek (see pp. 19, 29; Ref. 4 pp. 34, 36, 41, 57, 59, 61-62, 65-and 66 67). This contradicts McGrath North's assertion that contamination does not appear to be migrating to the surrounding community.

This comment has no effect on the HRS Site score or the decision to place the Site on the NPL.



### 3.3 Need for Remediation

Comment: McGrath North questioned the need for remediati on at this site, stating that it is agreed “that arsenic and lead contaminated soils should be pr evented from migrating off site; however, the present
situation is stable and a cl eanup is not time critical.”

Response: Listing a site on the NPL does not represent a finding that remedial action is necessary or will be taken, but that further investigation is necessary. Consideration of future response actions is not a
factor in the decision to list a site on the NPL. The remedy selection phase of the CERCLA process is a separate step, which occurs after appropriate remedi al investigations and risk assessments have been completed. In general, under the Superfund program, EPA investigates sites in two stages:

1. Site assessment: a screening-level evaluation of a ll sites to determine those for which response action may be required, culminating in the listi ng of sites on the NPL, where appropriate; and

2. Response action: a comprehensive evaluation of NPL sites to determine the nature and extent of contamination, and to select and impl ement any necessary site cleanup actions.

It is only in the second stage that EPA will be able to select an appropriate remedy, if any is needed, for a site. At this site, further study is necessary to dete rmine whether sufficient information is available to perform a complete site-specific risk assessment. Based on the site-specific risk assessment, EPA will then determine what remedy, if any, is necessary.

Regarding whether there is a need for a time critical removal action 1 , a site-specific risk assessment is normally performed after listing as a separate part of the Superfund process. See section 3.6 of this support document for further explanation of time critical removal actions.

1 Time critical removal actions are expedited removal actions used to address situations in which acute impacts are
imminent.

5Wright Chemical Corporation Listing Support Document March 2011

This comment has no effect on the HRS Site score or the decision to place the Site on the NPL.



### 3.4 Incomplete Exposure Route/No Risk

Comment: McGrath North questioned EPA’s conclusion that the source associated with the Wright Chemical Corporation site is impacting surface water quality or the biota or humans ingesting the biota within Livingston Creek. McGrath North also stated that Oak-Bark Corporation does not believe that the Site poses a significant threat to public health, welfare or the environment.

Response: The Site’s HRS score shows that the Site presen ts sufficient risk to be placed on the NPL for further study and possible response action.

A site-specific risk assessment will be performed as part of the Superfund response process that occurs after the listing process is completed. At that tim e, EPA will consider the information provided by
McGrath North. The results of the risk assessment will be considered if and when remedial options at the
Site are selected.

McGrath North’s assertion that it does not believe the Site poses a significant threat to public health, welfare, or the environment is not supported by a s ite-specific risk assessment. As the HRS score, HRS documentation record, and this support document shows, the Site poses sufficient th reat to public health, and the environment to warrant further investigation.

This comment has no effect on the HRS Site score or the decision to place the Site on the NPL.



### 3.5 Oak-Bark/Hexion Facility - No Further Effort Needed

Comment: McGrath North stated that adjacent to the former lead chamber sulfuric acid plant is a currently operating facility owned by Oak-Bark Corpor ation and Hexion. McGrath North identified that this facility has only been used for the manufactur ing of organic chemicals and products. Under the direction of the North Carolina Department of Environment and Natural Resources (NCDENR), four unlined lagoons were closed at the facility in 1994. A comprehensive site assessment (CSA) and a corrective action plan (CAP) were submitted in 1997. The CSA determined that arsenic and lead were not Site ground water contaminants and were theref ore not included in the CAP. In 1998, NCDENR approved the CAP for "using the natural attenuation pr ocess." McGrath North concluded by stating that ground water data (1997 to 2010) shows that the natural attenuation process is reducing the contaminant levels in the area of the facility.

Response: McGrath North’s comments about the adjacent facilities have no effect on listing the Wright Chemical facility. Because arsenic and lead were not found to be related to the four unlined lagoons at the neighboring facility does not affect the listing of contaminated soil at the Wright Chemical facility. The release at the Site is attributable, at least in pa rt, to releases associated with the denuded contaminated soil located on the Wright Chemical site, and neither the Oak Bark Corporation or Hexion facilities have been evaluated as part of this site (see sec tions 3.9.1 and 3.9.2 of this support document).

This comment has no effect on the HRS Site score or the decision to place the Site on the NPL.



### 3.6 Deferral to Other Programs

Comment: McGrath North questioned the appropriateness of listing the Wright Chemical Corporation site on the NPL, stating that there are at least two ot her State and/or Federal programs that would be more

6Wright Chemical Corporation Listing Support Document March 2011

appropriate for the Site. One program mentioned by McGrath North is NCDENR Inactive Hazardous Sites Branch Registered Consultant Program, or Voluntary Cleanup Program. A second and, McGrath North indicated, a more desirable program would be the EPA non-time or time critical removal action (NTCRA, TCRA), or the engineering evaluation and cost analysis (EE/CA) program. McGrath North stated that most of the former lead chamber/fertilizer sites are going through the EE/CA program or NTCRA process.

Response : This site qualifies for the NPL based on assi gnment of an HRS score above 28.50, and the State of North Carolina has requested that the S ite be placed on the NPL. None of the programs mentioned by McGrath North contain any provisions that would preclude EPA from pursuing the listing under CERCLA. Thus, EPA has no reason to defer this site to another EPA or other remedial program. In addition, the State support for the placement of th is site on the NPL demonstrates that the State does not wish the Site to be placed in an alternative state program. EPA does not consider that, based on the information presently available, the threat posed by the Site meets the criteria for imminent and substantial endangerment per Section 415(b) of the NCP for either a time critical or a non-time critical removal. If future evaluation during the RI/FS shows that a removal is needed, EPA will consider options
for a time or non-time critical removal at that time.

The Secretary for the NCDENR submitted a letter to the EPA Region 4 Administrator December 9, 2009, stating that the State of North Carolina agrees that th e Site poses a significant threat to the public health and the environment, and indicates State support of EPA's efforts to propose the Site for inclusion on the NPL (regulations.gov, Docket ID. EPA-HQ-SFUND-2010-0073). As stated in section 3.2 of this support document, the need for any site-specific response action is determined after listing at a different stage in the Superfund process.

This comment has no effect on the HRS Site score or the decision to place the Site on the NPL.



### 3.7 Description of In-Water Segment

Comment: McGrath North asserted that surface water near the Wright Chemical Corporation site is fresh water. McGrath North stated that adjacent to the Site is a freshwater swamp that is influenced by Livingston Creek.

Response : EPA agrees with the comment and acknowledg es that in the HRS documentation record at proposal the surface water near the Wright Chemical Corporation site is fresh water.

Page 24 of the HRS documentation record at proposal under the title, Definition of Hazardous Substance Migration Path for Overland/Flood Component, stated:



### The point where Livingston Creek flows into the Cape Fear River is 27 1/2 miles upstream from Wilmington. The point where the Cape Fear joins the Black River is the upstream intrusion limit (200 mg/L chloride), having a 50% chance of being equaled or exceeded in any one year (Ref. 4, pp. 296, 309). Saltwater intrusion may affect water quality as far as 20 miles upstream from Wilmington (Ref. 4, p. 300). Therefore, the first 10 1/2 miles of the surface water pathway is fresh, and the last 4 1/2 miles of the surface water pathway is brackish/salt.

Section 3.10.3 of this support document discusses th e assignment of factor values based on salinity and explains that whereas the substances used to assign the bioaccumulation factor value are different

7Wright Chemical Corporation Listing Support Document March 2011

depending on the salinity of the water, the bioaccumulation factor value remains the same regardless of the water salinity.

This comment has no effect on the HRS Site score or the decision to place the Site on the NPL.



### 3.8 Observed Release to Livingst on Creek – Significant Increase

Comment: McGrath North contested the observed release of contaminants to surface water, claiming that there has been no significant increase of contaminan t concentrations in water samples from Livingston Creek. McGrath North stated that as part of a Stat e of North Carolina CAP for addressing the closure of four unlined lagoons at Hexion, Livingston Creek was monitored upstream and downstream of the Site to document any potential impact. It continued by stating that from 1997 to 2003, the creek was sampled for chromium, copper, lead, and zinc with few con centrations above detec tion limits and none above background concentrations. It further stated th at surface water samples collected in 2009 and 2010 included analyses for arsenic and lead; none of the su rface water samples exhibited sample concentrations of lead or arsenic above the detection limit of 10 micrograms per liter (μg/L). In addition, McGrath North noted that cadmium was included in the March 17, 2010, sampling event and cadmium was not detected above the detection limit of 1 μg/L.

McGrath North asserted that, in summary, surface water analyses have shown no impact to surface water quality attributable to the former lead chamber acid pl ant. In addition, a surface water station used by the Center of Marine Sciences for UNC Wilmington is located along Livingston Creek. McGrath North stated that analytical results from samples collected 6 times per year between 2001 and 2006 indicated that all Priority Pollutant Metals (including arsen ic, cadmium, and lead) were not detected above analytical detection limits for all samples collected from Livingston Creek.

Response: The likelihood of release value for the Wright Chemical Corporation site was appropriately assigned according to the HRS, as an observed rel ease by chemical analysis was documented for Livingston Creek. The release was based on analytic al results from sediment samples collected from Livingston Creek. The HRS does not require that rel eases be based solely on surface water samples, nor does the absence of a release in surface water samp les negate releases established based on sediment samples.

HRS Section 2.3, Likelihood of release, states:

Likelihood of release is a measure of the lik elihood that a waste has been or will be
released to the environment. The likelihood of release factor category is assigned the maximum value of 550 for a migration path way whenever the criteria for an observed release are met for that pathway. If the crite ria for an observed release are met, do not evaluate potential to release for that pathwa y. When the criteria for an observed release are not met, evaluate potential to release for that pathway, with a maximum value of 500. The evaluation of potential to release varies by migration pathway (see sections 3, 4 and 6).

Establish an observed release either by dir ect observation of the release of a hazardous substance into the media being evaluated (fo r example, surface water) or by chemical analysis of samples appropriate to the pathway being evaluated (see sections 3, 4, and 6).
The minimum standard to establish an observed release by chemical analysis is analytical
evidence of a hazardous substance in the medi a significantly above the background level. Further, some portion of the release must be attributable to the Site. Use the criteria in table 2–3 as the standard for determining analytical significance. (The criteria in table 2–

8Wright Chemical Corporation Listing Support Document March 2011

3 are also used in establishing observed cont amination for the soil exposure pathway, see section 5.0.1.) Separate criteria appl y to radionuclides (see section 7.1.1).

Table 2–3—Observed Release Crit eria for Chemical Analysis

Sample Measurement < Sample Quantitation Limit a

No observed release is established. Sample Measurement ≥ Sample Quantitation Limit a

An observed release is established as follows:

• If the background concentration is not detected (or is less than the detection limit), an observed release is established when the sample measurement equals or exceeds the sample quantitation limit. a

• If the background concentration equals or exceeds the detection limit, an observed release is established when the sample measurement is 3 times or more above the background concentration.

a If the sample quantitation limit (SQL) cannot be established, determine if there is an
observed release as follows:

— If the sample analysis was performed un der the EPA Contract Laboratory Program, use the EPA contract-required quantitati on limit (CRQL) in place of the SQL.

— If the sample analysis is not performed under the EPA Contract Laboratory Program, use the detection limit (DL) in place of the SQL.

Further, HRS Section 4.1.2.1.1, Observed release , contains the directions used to establish an observed release to the surface water migration pathway. It states in part:

Establish an observed release to surface water for a watershed by demonstrating that the
site has released a hazardous substance to the surface water in the watershed. . . .

• Chemical analysis:

- Analysis of surface water, benthic, or sediment samples indicates that
the concentration of hazardous substa nce(s) has increased significantly above the background concentration for the site for that type of sample (see section 2.3). [emphasis added]

-Limit comparisons to similar types of samples and background concentrations – for example, compare surface water samples to surface water background concentrations.

-For benthic samples, limit comparisons to essentially sessile organisms.

- Some portion of the significant increase mu st be attributable to the site to establish the observed release, except: when the site itself consists of

9Wright Chemical Corporation Listing Support Document March 2011

contaminated sediments with no iden tified source, no separate attribution is required.

If an observed release can be established for a watershed, assign an observed release factor value of 550 to that watershed, enter th is value in Table 4-1, and proceed to section

4.1.2.1.3.

The significant increase in arsenic, cadmium, copper, lead, and zinc is documented in the HRS documentation record at proposal on pages 27-30 which include tables 4 and 6 that display the background and release concentrations of hazardous substances found in Livingston Creek and Mill
Creek sediments. These tables show that sedimen t samples WC-003-SD, WC-013-SD, and WC-006-SD meet the criteria for a significant increase as hazardous substances have been detected at concentrations significantly above background levels based on samples WC-001-SD WC-002-SD WC-008-SD WC-009- SD WC-010-SD. Contaminants qualifying for the obser ved release to Livingston Creek include arsenic, cadmium, copper, lead, and zinc.

Page 30 of the HRS documentation record at pro posal, under the heading “Hazardous substances in observed release summary,” stated:

Sample WC-003-SD and its duplicate WC -013-SD serve to document the observed release of arsenic, cadmium, copper, lead, a nd zinc into the fishery. While samples just downstream of the site (WC-004-SD and WC- 005-SD) did not show site contaminants, sample WC-006-SD showed higher levels of site contaminants.

Although McGrath North stated that surface water samples collected from 1997 to 2010 did not indicate metals contamination to Livingston Creek, the observed release of contaminants to Livingston Creek is
based on an evaluation of sediment samples collected during a 2007 Expanded Site Inspection (ESI) conducted by the North Carolina Superfund Section. As stated in HRS section 4.1.2.1.1, quoted above, an observed release can be established using water, sediment, or benthic samples.

It should be noted that the analytical results of su rface water samples, cited by McGrath North, do not demonstrate any error in the analysis of the sediment samples used to establish an observed release at this
site.

Therefore, a significant increase in hazardous substance concentration was correctly identified and there is no change to the HRS Site score or th e decision to place the Site on the NPL.



### 3.9 Observed Release by Chemical Analysis - Attribution

Comment: McGrath North questioned attribution at the Wright Chemical site. McGrath North asserted that any connection of the Wright Chemical Corporation site to Livingston Creek is an incomplete chain. McGrath North expressed its belief that the observed cont amination is widespread in the river basin and is not specific to Livingston Creek.

Response : The significant increases in metal concentrations in release samples (i.e., arsenic, cadmium, copper, lead, and zinc) were correctly attributed to the release from the Wright Chemical Corporation site.

HRS Section 2.3, Likelihood of release, presents the attribution requirement to establish an observed release by chemical analysis:

10Wright Chemical Corporation Listing Support Document March 2011

The minimum standard to establish an observed release by chemical analysis is analytical
evidence of a hazardous substance in the medi a significantly above the background level. Further, some portion of the release must be attributable to the site [Emphasis added].

Further, HRS Section 4.1.2.1.1, Observed release , contains the directions used to establish an observed release to the surface water migration pathway. It states in part:

Establish an observed release to surface water for a watershed by demonstrating that the
site has released a hazardous substance to the surface water in the watershed. . . .

• Chemical analysis:

- Analysis of surface water, benthic, or sediment samples indicates that the
concentration of hazardous substan ce(s) has increased significantly above the background concentration for the site for that type of sample (see section 2.3).

- Some portion of the significant increase must be attributable to the
site to establish the observed release [Emphasis added], except: when
the site itself consists of contam inated sediments with no identified source, no separate attribution is required.

As explained in this response, it is sufficient to a ttribute some portion of the release to a site when the
observed release substances are associated with a site source and no other facilities are the cause of the significant increase of hazardous substances

.

Pages 31 and 32 of the HRS documentation record at proposal under the heading, Attribution, presented the rationale for attributing the observed release of contaminants to the source (i.e., Source 1 - contaminated soil) associated with the Wright Chemical Corporation site:

The Wright Chemical Corp site was a fertilizer and sulfuric acid manufacturing facility founded in 1883 (Ref. 4 pp. 397, 401). The original Acme plant was a lead-lined “chamber-process” plant that thermally extracted sulfur from pyrite (Ref. 4 pp. 109). Sanborn Fire Insurance Maps dated from 1898 and 1910 confirm that “Lead Acid Chambers” were previously present on the pr operty where Source 1 has been identified (Ref. 4 pp. 173-179; Fig. 3).

Denuded, magenta-colored soil characteristic of former lead chamber sulfuric acid manufacturing facilities (Ref. 4 pp. 214-215) has been documented in the vicinity of the former process areas on the property (Ref. 8, pp. 1-8). This magenta colored soil typically contains lead in the 4,000 – 20,000 mg/kg range and depending on the raw materials used in the processes, it can also c ontain substantial amounts of other metals and contaminants (Ref. 4 p. 215). Source 1 has been documented to contain elevated concentrations of metals including arsenic, cadmium, copper, lead, and zinc (see Table 2 of this HRS documentation record) (Ref. 4, pp. 34, 36, 57-59, 61-63; Fig. 4).

Source 1 drains north, downgradient into Livingston Creek (Figs. 1, 4). Sediment samples taken from Livingston Creek directly downgradient from source 1 show elevated concentrations of metals analogous to those found in source 1 (Ref. 4, pp. 35-56, 87-93; Fig. 7).

11Wright Chemical Corporation Listing Support Document March 2011

There are three current/former fa cilities/sites that are upgradient from this site – Hexion, Kaiser Agricultural, and Kaiser Acme Farmarke t (Ref. 4, pp. 108, 109-110, 117; Ref. 9, 1-12). There are two nearby facilities/sites that are downgradient from Wright Chemical – International Paper (aka Fede ral Paperboard) and Holtrachem (Ref. 4, p. 3, Figs. 5, 6). The neighboring Hexion facility was at one time owned and operated by the Wright Chemical Corp. The history of chemical manufacturing on this adjacent 20-acre Hexion parcel included formaldehyde, hexamine , chloropicrin, silicon compounds and pharmaceuticals. There is no history of work with metals (Ref. 4, pp. 9, 129, 397-404). One sample (WC-010-SD; Tables 3, 4) was collected downgradient of Hexion and up gradient from Livingston Creek. This sample documents any impact to Mill Creek that may have occurred from runoff from the Hexi on site prior to it entering Livingston
Creek.

The archived Kaiser Agricultural Chemical s ite (NCD 980 842 470) adjacent to and south of the lead chamber properties was once part of Acme Chemical and was owned by Wright Chemical. This parcel housed the fertilizer portion of the operation, it was investigated under CERCLA, and was archiv ed from CERCLA in 1989 (Ref, 4, p. 110, 111). The former Kaiser Acme Farmarket (N CD 980 557 847) pesticide facility is about 1⁄4 mile to the south. This facility was associated with chlorinated pesticide manufacturing from 1967 – 1971 and subsequently for pesticide retail sales. There is no evidence it had metal contamination (Ref. 9, pp. 1-12).

To the north and across Livingston Creek is the 978-acre parcel owned by Federal Paper Board Co., Inc. (aka International Paper) (Ref . 4, p. 452.3; Fig. 5). Adjacent to and east of Federal Paper Board, bordering the Cape Fear River is the former Holtrachem (aka LCP Chemicals; Honeywell; Allied Signal) mercury cell chlor-alkali plant site (NCD 991 278 631), currently owned by Honeywell Interna tional (Ref. 4, pp. 452.4, 452.5; Fig. 6). Both of these sites are downgradient from the Wr ight Chemical Corp site. There is some flow reversal on Livingston Creek (Ref. 10, pp. 1, 2); however, neither the Holtrachem nor the International Paper site are associated with any lead, arsenic, cadmium, copper, or zinc contamination (Ref. 8, p. 2). Holtrach em has high contamination with mercury and PCBs (Ref. 8, p. 2).

As described in the HRS documentation record at pr oposal, at least part of the significant increase of hazardous substances found in sediment samples can be attributed to the Wright Chemical site. As explained in section 3.9.1 (Association with Site Source) of this support document and in HRS Section 2.2.2, the contaminants for which a significant increase in concentrati ons was established were associated with Source 1, the contaminated soil. Additionally, the background samples were collected from various areas to document the presence or absence of other po tential sources of contamination. Specifically, sediment samples WC-001-SD and WC-002-SD were collected from Livingston Creek at points upgradient of the PPE to document background conditions upgradient of Wright Chemical. Sediment sample WC-010-SD was taken from Mill Creek, which is downgradient of the PPE but upgradient of its confluence with Livingston Creek (see Figure 2 of th is support document for sample locations). These samples document that the contamination in the release samples was not coming from other upgradient sources. Section 3.9.2 (Other Facilities) of this support document, explains that other downgradient facilities are also not the cause of the significant increase in hazardous substances in Livingston Creek.

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### I HZWright Chemical Corporation Listing Support Document March 2011

McGrath North’s specific comments on attribution ar e addressed in the following subsections of this support document:

• Section 3.9.1 Association with Site Source

• Section 3.9.2 Other Facilities

3.9.1 Association with Site Source

Comment: McGrath North asserted that any connection of the Wright Chemical Corporation site to Livingston Creek is an incomplete chain.

Response: McGrath North did not explain what is meant by “incomplete chain.” If McGrath North was implying that EPA has not demonstrated that the contaminants have moved from the source into surface water and then actually migrated to a fishery and been found in a food chain organism, the HRS does not require that this chain be demonstrated to attribute a release to the site. As quoted above in section 3.9 (Observed Release by Chemical Analysis – Attributio n) of this support document, HRS Section 2.3 only requires at least part of the significant increase in ha zardous substances to have come from the site. The
remainder of this section documents that the substances are associated with the Site source. Section 3.9.2 (Other Facilities) of this support document explains that no other facilities in the area of the Site are documented as contributing to this release.

The significant increases in metals (i.e., arsenic, cadmium, copper, lead, and zinc) were correctly attributed, at least in part, to the release from the Wright Chemical site. The contaminants associated with the observed release sediment samples are the same c ontaminants associated with the Wright Chemical site source. Additionally, as discussed below, the Wright Chemical site contains evidence of direct deposition of the contaminants into Livingston Creek.

HRS Section 4.0.2, Surface water categories , states in part:

For HRS purposes, classify surface water into four categories: rivers, lakes, oceans, and
coastal tidal waters.

Rivers include:

• Perennially flowing waters fro m point of origin to the ocean or to coastal tidal waters, whichever comes first, and wetlands contiguous to these flowing waters.

Section 2.2, Source Characterization, of the HR S documentation record at proposal documented
association of hazardous substances with Source 1:

The source is contaminated soil as defined by samples WC-011-SS, WC-012-SS and
WC-013-SS documented in the Table 1. These sa mples were collected near the former lead chambers and in the area where both 1) waste materials were placed and 2) overland
flow from the former lead/acid chambers on the facility was received (Ref. 8, p. 7; Fig. 4). This area of denuded soil has a purplish/magenta coloration and appears fairly consistent between the three samples (Ref. 8, pp. 1, 3-5). This area remains unfenced and is outside any runoff control features. (Ref. 8, pp. 1, 3-5) It is accessible but there are no signs of recreation. (Ref. 8, pp. 1, 3-5)

The source area was observed to consist of th ree contiguous subareas. These areas are, from south to north: Area a) an upland area of denuded soils where the former lead chambers had been located, Area b) a wooded slope covered at least in part with

14Wright Chemical Corporation Listing Support Document March 2011

bulldozed material similar to that observed in the former lead chamber area a), and Area c) a lowland area of contaminated soils. Source soil sample WC-012-SS was collected from Area a) while source soil samples WC-011-SS and WC-013-SS were collected from Area c), which extends to the probable point of entry (PPE) into Livingston Creek, and coincides, generally, with an area classified as non-HRS qualifying wetland type PUBH (Ref. 8, p. 7; Fig. 4)

The HRS documentation record at proposal on page 20 listed the contaminants associated with Source 1, which are antimony, arsenic, cadmium , copper, lead, manganese, mercury, nickel, silver, thallium, and zinc. Therefore, the cont aminants found in the observed release samples are
associated with Source 1.

In addition, there is evidence of direct deposition of the observed release s ubstances (arsenic, cadmium, copper, lead, and zinc) used to establish an observed re lease by chemical analysis into Livingston Creek. Discussion of this direct deposition into Livingston Creek has been added to the attribution discussion in the HRS documentation record at promulgation; this a ddition does not change the site score. As shown in Figure 4 of the HRS documentation record at propos al, samples WC-11-SS and WC-13-SS are located in a wetland contiguous to Livingston Creek. As di scussed above, according to HRS Section 4.0.2 these wetlands are considered part of Livingston Creek; th e location of these samples is also adjacent to the contaminated segment of the Creek. Therefore, this direct deposition demonstrates that hazardous substances have been released directly into the Creek and at least some portion of the significant increase is attributed to the Wright Chemical site.

This comment has no effect on the HRS Site score or the decision to place the Site on the NPL.

3.9.2 Other Facilities

Comment: McGrath North raised several issues identifyi ng other facilities that could be possible sources of the contamination in Livingston Creek, particularly when tidal influence is considered. McGrath North questioned attribution of the significant increase in the observed release contaminant concentrations to Wright Chemical given the existence of these othe r facilities in the area of the Wright Chemical Corporation site that could also be releasing contamination into Livingston Creek.

McGrath North stated that Livingston Creek is subject to minor tidal influences, usually less than one foot. However, it asserted that the water shifts and the resulting water level could range in excess of six feet in response to extended rainfall in combination with wind shifts and the resulting water level in the Cape Fear River.

Concerning other possible facilities contributing to th e release, McGrath North stated that the HRS documentation record at proposal identifies the existe nce of three current/former facilities (i.e., Hexion, Kaiser Agriculture, and Kaiser Acme Farmarket) upgr adient of the Site and two nearby facilities (i.e., International Paper, Holtrachem) downgradient of the Site. The issue that McGrath North raised addresses the attribution to the Wright Chemical site of contaminants detected in sediment sample WC006-SD, collected 2,750 feet downstream of the PPE. McGrath North pointed specifically to observed release sample WC-006-SD: it stated that the levels of arsenic, cadmium, and lead concentrations in the observed release sample are “higher than the levels in the swamp area closer to the source area.” McGrath North concluded that “this sample appears to be an anomaly and it is not clear where the contamination in this sample originated.”

McGrath North asserted that aquatic biota samples in nearby streams also suggest the contamination in
the Creek could have come from other sites. It st ated that the ESI, the HRS documentation record, and

15Wright Chemical Corporation Listing Support Document March 2011

other information indicate that clam and fish tissues sampled in 2004 showed that metals and pesticides exceeded their respective recommended concentrations. This claim referenced a published study report, Environmental Assessment of the Lower Cape Fear River System, 2003-2004 , prepared by Dr. Michael A. Mallin, et al , dated October 2005. Chapter 4 of this report states that bottom dwelling fish and clams in Rockfish Creek, Livingston Creek, and Six Runs Creek showed levels unsafe for human consumption for arsenic, cadmium, mercury, and selenium. The location of the sampling point in the Livingston Creek for this study was 40 meters from the confluence with Cape Fear River. Due to the tidal nature of the surface
water bodies in the area and the similar concentrations of contaminants in the three water bodies sampled, McGrath North stated that this study indicates that co ntamination is widespread within the river basin and is not specific to Livingston Creek.

McGrath North also referred to e-mail correspondence w ith Dr. Michael Mallin, author of the study and a research professor with the University of North Caro lina Wilmington, who stated, "I do not believe that Livingston Creek is the sole source of contamination; it is likely one of several sources." Dr. Mallin also stated that there is a coal-fired power plant 20 km downriver near Wilmington that potentially contributes various chemicals (Se, As, Hg) to the tidal river and airborne emissions from that plant and even power plants in the Piedmont may influence biota at that station (i.e., a surface water monitoring station located at Livingston Creek, 40 meters from its confluence with the Cape Fear River). Dr. Mallin also mentions a former industry (Holtrachem) upstream of Livingston Creek on the Cape Fear River that polluted the area with mercury for many years.

Response : Sufficient information exists to indicate that at least part of the significant increase in the release substances, as defined in HRS Section 2.3 and explained in section 3.8 of this support document, does not originate from other facilities either upgradient or downgradient of the Wright Chemical site.

Samples were collected in locations both upgradient a nd downgradient of the Wright Chemical site to document that other sites are not the entire cause of the significant increase in the observed release substances in the sediment samples.

The samples identified as from background locations in the HRS documentation record at proposal (see section 3.8 of this support document and page 27 of the HRS documentation record at proposal) were collected upgradient and adjacent to the Wright Chem ical site to screen out the possibility of releases from upgradient facilities. Sediment samples WC-001- SD and WC-002-SD were taken upgradient of the Wright Chemical site in Livingston Creek, a nd sediment samples WC-008-SD, WC-009-SD, and WC010-SD were collected on Mill Creek (tributary to Livingston Creek) adjacent to the Wright Chemical site. Any contamination from upgradient sources would be reflected in the contaminant concentrations in these background samples. Specifically, sediment samples WC-001-SD and WC-002-SD show that upgradient facilities of Kaiser Agricultural Chemical and Kaiser Acme Farmarket are not responsible for contamination found in the observed release samples, and sediment sample WC-010-SD similarly shows that the neighboring Hexion facility is also not r esponsible for the contamination found in the observed release samples. If contamination were coming from these other upgradient facilities, the background samples would have reflected the contamination.

Although not identified as a background sample at proposal, sediment sample WC-007-SD was taken 1200 feet downgradient of the most distant downgr adient observed release sample from the Wright Chemical source (sediment sample WC-006-SD) ( see Figure 2 of this support document for sample locations). Therefore, sample WC-007-SD can be used to screen out the possibility that potential contaminants migrated upgradient by tidal influence. If contaminants were migrating upgradient due to tidal flow, concentrations of the contaminants due to migration would be reflected in sample WC-007-SD. If this sample were used as a background sample, th e same observed releases would be identified as those identified when the upgradient background samples we re used. The concentrations of the observed

16Wright Chemical Corporation Listing Support Document March 2011

release substances -- arsenic, cadmium, copper, lead , and zinc (see Table 6 of the HRS documentation record at proposal) -- are actually lower in samp le WC-007-SD than in the upgradient background samples (see Table 4 of the HRS documentation record at proposal). Therefore, if WC-007-SD were used to establish a background level for contamination migrating upgradient during tidal reversal, the observed release criteria would still be met in the three samp les used to establish the observed release at proposal (WC-003-SD, WC-013-SD, WC-006-SD). For example, the copper concentration in sample WC-007-SD was 22 mg/kg. When this concentration is compar ed to the levels of copper in samples WC-003-SD, WC-013-SD, and WC-006-SD, which ar e 155, 122, and 631 mg/kg, respectively, a significant increase is identified according to HRS Table 2.3. In other wo rds, if sample WC-007-SD had been identified as a background sample, the concentrations of contamin ants in the observed release samples would be significantly greater and the observed release would still be established.

Regarding McGrath North’s comment that the contamin ant levels in sample WC-006-SD are higher than samples taken closer to Source 1, the higher contaminan t levels do not demonstrate that the contamination in sample WC-006-SD is not attributable at least in part to Wright Chemical. This contamination is considered attributable at least in part to Wright Chemical because as explained above: 1) the observed release contaminants are all associated with Source 1; 2) the observed release contaminants are not thought to come from downgradient sources because sample WC-007-SD contains contaminant levels below three times background concentra tions and effectively screens out this possibility; 3) InternationalPaper and Holtrachem operations are not associated with all of the contaminants found in sample WC006-SD; and 4) there are no other known sources of contamination entering Livingston Creek between the PPE and sample WC-006-SD.

Thus, although there is potential for tidal influen ce to reach Livingston Creek, the samples identified as background samples and sample WC-007-SD show that the significant contamination increases in the observed release samples are not originating from other facilities.

In addition, there is no evidence that other sites have released several of the observed release contaminants (arsenic, cadmium, c opper, lead, and zinc), and McGrath North did not provide any data showing that other facilities are associated with the observed release contaminants at the observed release sample locations. Further, in researching this issu e, no rationale for associating the observed release contaminants with other nearby facilities could be fou nd. The table below identifies the relative locations of the surrounding facilities as shown in Table 1 of this support document (see Figure 2 of this support document for sample locations).

Table 1: Relative Location of Surrounding Facilities

Company Direction from Wright
Chemical site Kaiser Agricultural
Chemical Upgradient

Kaiser Acme Farmarket Upgradient

Hexion Upgradient of one of the
three observed release samples

Holtrachem Downgradient International Paper Downgradient

With respect to McGrath North's comments regarding the published study (Environmental Assessment of the Lower Cape Fear River System, 2003-2004) a nd Dr. Mallin's e-mail correspondence regarding other sources in the area identifying that there are other facil ities in the lower Cape Fear River that could be the

17Wright Chemical Corporation Listing Support Document March 2011

cause of contamination in Livingston Creek, the HRS sco re is not dependent on identifying the sources of contamination at the sampling point referred to in Dr. Mallin’s study. The HRS score is based only on contamination from sample WC-003-SD to sample WC-006-SD being attributable to the Wright Chemical site. The contamination at the sample point utilized in Dr. Mallin's study (i.e., 40 meters above the confluence of Livingston Creek and Cape Fear River) is not attributed to the Wright Chemical site.

This comment has no effect on the HRS Site score or the decision to place the Site on the NPL.



### 3.10 Waste Characteristics

3.10.1 Waste Quantity

Comment: McGrath North commented on the dimension of Source 1. It stated that preliminary soil borings indicate that the thickness of the ma genta stained soil is less than two feet.

Response : A waste quantity of “greater than 0” was assigned to Source 1 in accordance with the HRS. The dimensions of a source can be used in determining a volume estimate for establishing the HRS source and pathway waste quantity factor. However, in this case, volume was not used in this estimation due to the lack of information regarding the accuracy of the estimate that the contamination is less than two feet below surface throughout the source and that the contam ination is limited to areas of visible stain.

The estimate of hazardous waste quantity for Source 1 and for the surface water pathway was developed in accordance with HRS requirements.HRS Section 2.4.2, Hazardous Waste Quantity , states:

Evaluate the hazardous waste quantity factor by first assigning each source (or area of observed contamination) a source hazardous waste quantity value as specified below.
Sum these values to obtain th e hazardous waste quantity factor value for the pathway being evaluated.

HRS Section 2.4.2.1, Source hazardous waste quantity , states:

For each of the three migration pathways, assign a source hazardous waste quantity value to each source (including the unallocated source) having a containment factor value greater than 0 for the pathway being evaluated. Consider the unallocated source to have a containment factor value greater than 0 for each migration pathway.

. . . .

For all pathways, evaluate source hazardous waste quantity using the following four measures in the following hierarchy:

• Hazardous constituent quantity [Tier A]

• Hazardous wastestream quantity [Tier B]

• Volume [Tier C]

• Area [Tier D]

For the hazardous constituent quantity, the total ma ss of CERCLA hazardous substances allocated to the source has not been documented, thus the use of Ti er A was not applicable in determining hazardous waste quantity. In addition, there was not adequa te information to calculate Tier B (Hazardous wastestream quantity) or Tier C (Volume). Rega rding a volume estimate, HRS Section 2.4.2.1.3,

18Wright Chemical Corporation Listing Support Document March 2011

Volume , states that if the volume cannot be determined, assign the source a value of 0 for the volume measure and proceed to HRS Section 2.4.2.1.4, Area, which states:

Evaluate the area measure using the area of the source (or the area of the area of observed contamination). Based on this area, designated as A, assign a value to the area measure
as follows:

• For the migration pathways, assign the source a value for area using the appropriate Tier D equation of table 2-5

Page 21 of the HRS documentation re cord at proposal described how the hazardous waste quantity for Source 1 was established using an estimated area of the source. It stated:

Volume - Sufficient evidence does not exist to evaluate Volume

Area - Three points were collected in th e former lead chamber / surface impoundment area; the area of contaminated soil is determined to be >0 (Ref. 4, pp. 108, 109, 115-117, 120, 128, 161, 173-179, 180-182. 186, Figure 3)

Area assigned value (Ref. 1, Table 2-5) = A/34,000 = >0

A volume estimate was not evaluated because the information provided does not support that the contaminated soil is consistently less than two feet in depth across the entire source area. Although there are points of contaminated soil, the exact extent of the contamination based on the limited sampling is not known either vertically or horizontally. Therefore, an estimated area of "unknown but >0" was evaluated for Source 1 (i.e., contaminated soil). This area estimate is the lowest value assignable and is likely an underestimate of the actual area of contaminated soil. For example, in McGrath North’s attachment (i.e., Figure 3 - Approximate Area of Contamination, prepared by Shields Engineering Inc., April 2010), the area of contaminated soil was delineated to be appr oximately 6-acres (see section 3.2 of this support document). If the actual area of contaminated soil we re assigned a larger area value, it could only add to
the site score as the site score could onl y increase as the waste quantity increases.

Even if McGrath North's estimate of 6 acres of contaminated soil at a maximum depth of two feet were used to evaluate Tier C (Volume), the HRS site score would remain unchange d. This estimate would result in 522,720 ft 3 (43,560 ft 2 per acre x 6 acres x 2 feet in depth) which results in 19,360 yd 3 (522,720
ft 3 / 27). Table 2-5 of the HRS states that the volume is to be divided into 2,500 (i.e., V/2,500), which results in a source hazardous waste quantity of 7.744 us ing the volume estimate. This value results in a pathway hazardous waste quantity factor value of 1 from HRS Table 2-6; however, since targets are subject to Level II concentrations for this site, the pathway waste quantity factor value of 100 applies. This is the same pathway hazardous waste quantity factor value assigned in the HRS documentation record at proposal based on a waste quantity estim ate of >0 (see page 39 of the HRS documentation record at proposal).

As discussed above, the hazardous waste quantity fo r Source 1 and for the surface water pathway at proposal was developed in accordance with HRS requirements. McGrath North's statement of preliminary soil borings indicating a thickness of the ma genta stained soil less than two feet has no impact
on the HRS evaluation.

This comment has no effect on the HRS Site score or the decision to place the Site on the NPL.

19Wright Chemical Corporation Listing Support Document March 2011

3.10.2 Eligible Hazardous Substances

McGrath North questioned the inclusion of cadmium in evaluating the waste characteristics associated with Source 1. McGrath North stated that the subject of this action is arsenic and lead contamination generated by the Acme Manufacturing Company and Wr ight Chemical Corporation from the operation of a lead chamber acid plant that began operation in 1883 . McGrath North stated that the target of the proposed listing of the Wright Chemical Corporation site is the contamination associated with the former lead chamber sulfuric acid manufacturing plant and that cleanups of similar acid plants have been driven by the contaminants arsenic, lead, and low pH. McGrat h North further stated that the ESI determined low concentrations of cadmium present in soil and sedim ents. McGrath North questioned the validity of HRS scoring using the minor site contaminant cadmium to evaluate the Human Food Chain Threat. McGrath
North stated that cadmium is not a contaminant associ ated with the former acid plant and that the Human Food Chain Threat should have been evaluated using arsenic and lead, as these substances have been used
to evaluate similar sites.

Response: Hazardous substances, including cadmium were associated with Source 1 at the Wright Chemical Corporation site according to the HRS.

HRS Section 1.1, Definitions , states:

Source: Any area where a hazardous substance has been deposited, stored, disposed, or placed, plus those soils that have become contaminated from migration of a hazardous
substance. ...

HRS Section 2.2.2, Identify hazardous substances associated with a source, states:

For each of the three migration pathways, consider those hazardous substances documented in a source (for example, by sampling, labels, manifests, oral or written statements) to be associated with that so urce when evaluating each pathway. In some instances, a hazardous substance can be doc umented as being present at a site (for example, by labels, manifests, oral or written statements), but the specific source(s) containing that hazardous substance cannot be documented. For the three migration pathways, in those instances when the specific source(s) cannot be documented for a hazardous substance, consider the hazardous subs tance to be present in each source at the site, except sources for which definitive information indicates that the hazardous substance was not or could not be present.. . . .

Further, HRS Section 2.2.3, Identify hazardous substances available to a pathway, states:

In evaluating each migration pathway, co nsider the following hazardous substances available to migrate from the sources at the site to the pathway:

• Ground water migration.....

• Surface water migration—overland/flood component.

- Hazardous substances that meet the criteria for an observed release to surface water in the watershed being evaluated.

- All hazardous substances associated with a source with a surface water containment factor value greater than 0 for the watershed (see sections 4.1.2.1.2. 1.1 and 4.1.2.1.2.2.1)....

20Wright Chemical Corporation Listing Support Document March 2011

Table 2 on page 19 of the HRS documentation reco rd at proposal presented the contaminants and corresponding concentrations from Source 1 soil sampl es and the background soil sample. This table is
shown below.



### Table 2. Source Soil and Background Soil Results
Units mg/kg CRQL WC-011-SS WC-012-SS WC-013-SS WC-014-SS* (Background)

(Ref. 5) Ref. 4, pp. 34, 36, 57, Ref. 4, pp. 34, 36, 59 Ref. 4, pp. 34, 36, 61, 62 Ref. 4, pp. 34, 36, 63



### Antimony** 6 69 J [34.8] 63 J [31.8] 86 J [43.4] 8.3 UJ (8.3 U)

Arsenic** 1 430 J [247] 700 J [402] 900 J [517] 1.4 J*
Cadmium 0.5 42 31 40 0.69 U Copper** 2.5 210 J [172] 720 J [590] 890 J [730] 1.9 J* (3.5 U)

Lead** 1 3500 J [2430] 7800 J [5417] 10000 J [6944] 16 J [23] Manganese 1.5 32 27 27 8.9

Mercury 0.1 2.4 2.4 35 0.056 J* (0.50 U)

Nickel 4 20 17 19 1.9 J* (5.5 U)

Silver 1 18 29 43 1.4 U
Thallium 2.5 16 22 28 3.5 U
Zinc 6 7500 4700 6700 14 J

J = estimated value “U” indicates non-detect. The number adjacent to the “U” or inside () is the MRL. [ ] provides the adjusted value for the estimated (J’d) value as ad justed for bias (Ref. 4, pp. 266 - 283). *( ) = Minimum Reporting Limit (MRL) is shown in parentheses when a trace value is reported below the MRL. The MRL is the analyte concentration which co rresponds to the lowest quantitative point on the
calibration curve or the lowest demonstrated leve l of acceptable quantitation (Ref. 4, p. 36). Trace levels below reporting limits are treated as non -detect (Ref. 1, Table 2-3; Ref. 4, p. 269).

**Flagging of data in the data reports (Ref. 4, pp 37 – 86) is inconsistent with statements in the data report (Ref. 4, pp. 34, 68). Generally, the narrative indicates some data should be J-qualified while data sheets did not show a J. Where a conflict appeared, the data was treated as J’d and subsequently adjusted as appropriate. Data were adjusted per “Using Qua lified Data to Document an Observed Release and Observed Contamination”, to illustrate the relative increase of hazardous substance concentrations of background levels (Ref. 4, pp. 266-283). This is a conservative approach.

**Arsenic and copper results are J’d due to high bias (Ref. 4, p. 34). Background is not adjusted; source/release results are adjusted downward by correc tion factor of 1.74 for arsenic and 1.22 for copper (Ref. 4, pp. 270, 283). Antimony and lead results ar e J’d due to uncertain bias. Because matrix spike sample recovery for antimony and lead were low, and because performance evaluation sample recovery were “action high” (Ref. 4, p. 34), data was adjusted based on uncertain bias (Ref. 4, pp. 34, 270, 273, 283). Background is adjusted upward and source/release results are adjusted downward by correction factor of 1.98 for antimony and 1.44 for lead (Ref. 4, pp. 270, 283).

BOLD = Observed contamination, which is greater than or equal to 3 times background when detected in background, or greater than background quantitati on limit (aka MRL) and CRQL if background is nondetect (Ref. 1, Table 2-3; Ref. 4, p. 266). Note that source samples were compared to background soil sample in Table 2.

21Wright Chemical Corporation Listing Support Document March 2011

Table 2, above, documents that the soils in Source 1 came to be contaminated by demonstrating the level of several hazardous substances, including cad mium are present in the soil significantly above background levels and not just present at natural le vels. Table 2 shows that Source 1 soil samples WC011-SS, WC-012-SS, and WC-013-SS all contain concentr ations of contaminants that are above three times the background level found in sam ple WC-014-SS. The analytical data indicates that in addition to lead and arsenic, antimony, cadmium, copper, manganese, mercury, nickel, silver, thallium, and zinc were detected at concentrations significantly greater than concentrations of these substances detected in the background soil sample. Cadmium was detected in three source samples at concentrations ranging from 31 to 42 mg/kg, which are significantly greater than de tected in the background soil sample. Therefore, the association of all the metals, including cadmium, ar e properly associated with the contaminated soils
and included in the evaluation of the Human Food Chain Threat.

This comment has no effect on the HRS Site score or the decision to place the Site on the NPL.

3.10.3 Assignment of Bioaccumulation Factor Values

Comment: McGrath North stated that a freshwater swamp, influenced by Livingston Creek, is located immediately adjacent to the Site.

Response: The salinity of Livingston Creek is used in determining the bioaccumulation factor value for the site. Upon review of the assignment of these values, the bioaccumulation factor values for each
substance has been revised in the HRS documentati on record at promulgation to use the appropriate bioaccumulation potential factor value for the human food chain threat in accordance with the provisions
of the HRS.

HRS Section 4.1.3.2.1.3, Bioaccumulation potential , directs the assignment of the bioaccumulation factor
value:

....

• If BCF data are available for both fresh water a nd salt water for the hazardous substance, use the BCF data that correspond to the type of water body (that is, fresh water or salt water) in which the fisheries are located to assign the bioaccumula tion potential factor value to the hazardous
substance.

Further, HRS Section 4.1.3.2.1.4, Calculation of toxicity/persistence /bioaccumulation factor value, directs which value is to be used in scoring the Site:

Assign each hazardous substance a toxicity/persistence factor value from table 4–12, based on the values assigned to the hazardous s ubstance for the toxicity and persistence factors. Then assign each hazardous substan ce a toxicity/persistence/bioaccumulation factor value from table 4–16, based on the valu es assigned for the toxicity/persistence and bioaccumulation potential factors. Use th e hazardous substance with the highest toxicity/persistence/bioaccumulation factor value for the watershed to assign the value to
this factor. Enter this value in table 4–1.

Section 4.1.3.2.1 (Toxicity/Persistence/Bioaccumulation) on pag es 33-34 of the HRS documentation record at proposal, presented the bioaccumulation fa ctor values and resulting Toxicity/Persistence/ Bioaccumulation Potential Factor values (T/P/BPFV ) for each of the hazardous substances associated with Source 1, and provided the citation to the source of the assigned values:

22Wright Chemical Corporation Listing Support Document March 2011

The HRS instructs to evaluate the waste characteristics factor category based on two factors: toxicity/ persistence and hazardous waste quantity. And, to evaluate only those
hazardous substances that are available to mi grate from the sources at the property to
surface water in the watershed via the overla nd/flood hazardous substance migration path
for the watershed. Such hazardous substan ces include hazardous substances that meet the
criteria for an observed release to surface water in the watershed, and all hazardous
substances associated with a source that has a surface water containment factor value greater than 0 for the watershed (Ref. 1, Section 4.1.2.2, also see sections 2.2.2

, 2.2.3

, 4.1.2.1.2.1.1 , and 4.1.2.1.2.2.1 ). Tables 7 and 8 of this HRS documentation record present those substances documented in the ob served release to the fishery, and those
substances documented in the source with a c ontainment factor value greater than 0.

As discussed above, Livingston Creek (3 miles) and the first 7 1⁄2 miles in the Cape Fear River is fresh, and the last 4 1/2 miles of the surface water pathway is brackish/salt. (See discussion in 4.1.1.1 above; Ref. 4, pp. 296, 300, 309).

Table 7. Source 1 Contaminants Documented in Observed Release to Sediment in the Fishery

Hazardous Substance Tox.
Factor
value PF # BPFV*
Fresh
Food** BPFV* Salt
Food** T/P value (Ref. 1, Table 4-12) T/P/BPFV (fresh) (Ref. 1,

Table 4-16) T/P/BPFV (salt) (Ref. 1, Table 4- 16)

A rsenic 10,000 1 5 500 10,000 5 x 10 E4 5 x 10 E6
Cadmium 10,000 1 5,000 50,000 10,000 5 x 10 E7 5 x 10 E8 Copper 0 1 500 50,000 0 0 0
Lead 10,000 1 5 5,000 10,000 5 x 10 E4 5 x 10 E7
Zinc 10 1 5 50,000 10 50 5 x 10 E5

Table 8. Source 1 Contaminants Documented in Source with Containment Factor of 10, not documented in Observed Release to Fishery Sediment

Hazardous Substance Tox.
Factor
value PF # BPFV*
Fresh
Food** BPFV* Salt
Food** T/P value (Ref. 1, Table 4-12) T/P/BPFV (fresh) (Ref. 1,

Table 4-16) T/P/BPFV (salt) (Ref. 1, Table 4- 16)

A ntimony 10,000 1 5 5 10,000 5 x 10 E4 5 x 10 E4 Manganese 10,000 1 50, 000 50,000 10,000 5 x 10 E8 5 x 10 E8 Mercury 10,000 1 50,000 50,000 10,000 5 x 10 E8 5 x 10 E8
Nickel 10,000 1 0.5 500 10,000 5 x 10 E3 5 x 10 E6
Silver 100 1 50 50,000 100 5 x 10 E3 5 x 10 E6
Thallium 100 1 500 50 100 5 x 10 E4 5 x 10 E3 T/P/BPFV = Toxicity/Persistence/Bioaccumulation Po tential Factor (Ref. 1, Table 4-16) **Ref. 2, Appendix BI, pp. 1-15
BPFV = Bioaccumulation Potential Factor Value

# PF = Persistence Factor Value, Re f. 1, Section 4.1.3.2.1.2; Ref. 2
*Ref. 1, Section 4.1.3.2.1.3; Ref. 2

.

In the HRS documentation record at proposal, the hi gher of the saltwater and freshwater Bioaccumulation Potential Factor Values (BPFVs) was assigned in evaluation of waste characteristics. Therefore, at proposal the highest Toxicity/Persistence Bioaccumula tion Potential Factor Values (T/P/BPFV) were for cadmium, manganese, and mercury (i.e., 5 x 10 E8). However, since the human food chain fishery being evaluated is located in a freshwater portion of Livi ngston Creek the BPFVs should have only included those values for freshwater (HRS documentation record page 24). Therefore, cadmium should have a T/P/BPFV of 5 x 10 E7 (fresh) instead of 5 x 10 E8 (salt) as listed in the HRS documentation record at proposal. The HRS document record has been revi sed at promulgation to make this correction.

23Wright Chemical Corporation Listing Support Document March 2011

This change has no effect on the HRS score for the Site . The HRS states in Section 4.1.3.2.1.4, to use the factor value having the highest combined T/P/BPFV . In this case for freshwater, both Manganese and Mercury have the highest possible T/P/BPFVs of 5 x 10 E8, the same value used at proposal.

This comment has no effect on the HRS Site score or the decision to place the Site on the NPL.

3.10.4 Containment

Comment: McGrath North challenged the identification of a lack of containment for Source 1 by stating
that arsenic and lead contaminated soils should be prevented from migrating off site; however, the present situation is stable and a cleanup is not time critical. McGrath North also stated that as seen on Figure 3, the probable extent of contamination can be fairly readily seen and that contamination does not appear to be migrating to the surrounding community.

Response : The containment value for Source 1 was correctly assigned in the evaluation of the Site. HRS
Section 4.1.2.1.2.1.1 states:

HRS Table 4-2 lists the Containment Factor Values for the Surface Water Pathway:

Source Assigned value All Sources (Except Surface Impoundments, Land Treatment, Containers, and Tanks)

Evidence of hazardous substance migration from source area ( i.e. , source area includes source and any associated containment structures).

No evidence of hazardous substa nce migration from source area and:

( a) Neither of the following pr esent: (1) maintained engineered cover, or (2) functioning and maintained run-on control system and runoff management system

(b) Any one of the two items in (a) present

(c) Any two of the following present: (1) maintained engineered cover, or (2) functioning and maintained run-on c ontrol system and runoff management system, or (3) liner with functioning leachate collection and removal system immediately above liner

(d) All items in (c) present

(e) All items in (c) present, plus no bulk or non-containerized liquids nor materials containing free liquids de posited in source area.

No evidence of hazardous substance migr ation from source area, double liner with functioning leachate collec tion and removal system a bove and between liners, and:

(f) Only one of the following deficiencies present in containment: (1) bulk or noncontainerized liquids or materials containing free liquids deposited in source area, or (2) no or nonfunctioning or nonm aintained run-on control system and runoff management system, or (3) no or nonmaintained engineered cover

(g) None of the deficiencies in (f) present.

Source area inside or under maintained inta ct structure that provides protection from precipitation so that neither runoff nor leac hate is generated, liquids or materials containing free liquids not deposited in sour ce area, and functioning and maintained runon control present 10

10

9

7

5

3

3

0

24Wright Chemical Corporation Listing Support Document March 2011

Page 16 of the HRS documentation record at pro posal documented the assignment of the containment
value for this source. The containment value was a ssigned from Table 4-2 of the HRS. Specifically, a containment value of 10 for Source 1 was assigned based on the following:

• Contaminated soil is outside any controlled runo ff feature and is available for continuous and ongoing overland flow (Ref. 1, Table 4-2; Ref. 8, pp 1. 3-5).

• An observed release of site contaminants to Livi ngston Creek (Ref. 1; Ref. 4, pp. 34, 36, 41, 47, 65, 66; Table 4-9)

Since no containment features are present at the S ite and there is evidence of hazardous substance migration from the Site, the containment value of 10 for Source 1 was correctly assigned in accordance
with the HRS.

This comment has no effect on the HRS Site score or the decision to place the Site on the NPL.



### 3.11 Targets

3.11.1 Presence of Private Receptors

Comment: McGrath North questioned the presence of target s in the vicinity of the Wright Chemical Corporation site. McGrath North stated that in spite of being in a rural part of the county, the Site is surrounded by former or current industrial facilities. McGrath North further stated that there are no potential private receptors that could be affected by releases at the Wright Chemical Corporation Site.

Response: It is unclear what McGrath North means by the term "private receptors"; however, the only target (receptor) included in the HRS evaluation was a human food chain fishery. The presence of a human food chain target (i.e., receptor) in the Li vingston Creek fishery was properly established according to the HRS as an eligible target. The HRS makes no distinction regarding “private” receptors.

The HRS identifies that human food chain fisheries are eligible targets. HRS Section 4.1.3.3, Human food chain threat - targets , states:

Evaluate two target factors for each watershed: food chain individual and population. For both factors, determine whether the target fisheries are subject to actual or potential
human food chain contamination.

Further, HRS Section 4.1.3.3.1, Food chain individual, states:

Evaluate the food chain individual factor based on the fisheries (or portions of fisheries) within the target distance limit for the watershed. ...

HRS Section 4.1.3.3.2, Population, states:

Evaluate the population factor for the watershed based on three factors: Level I concentrations, Level II concentrations, a nd potential human food chain contamination. Determine which factor applies for a fishery (or portion of a fishery) as specified in
section 4.1.3.3.

4.1.3.3.2.1 Level I concentrations.....

25Wright Chemical Corporation Listing Support Document March 2011

4.1.3.3.2.2 Level II concentrations. Determine those fisheries (or portions of fisheries) within the watershed that are subject to Le vel II concentrations. Do not include any fisheries (or portions of fisheries) alrea dy counted under the Level I concentrations
factor.

Page 36 of the HRS documentation record at pro posal under the title, Human Food Chain Threat – Targets, identified an eligible fishery target:



### Livingston Creek, from WC-001-SD upstream of Old Highway 87 until its confluence with the Cape Fear River is a fishery. Brim, bass and catfish are caught in the creek, and catches are cooked and consumed on the creek banks (Ref. 4, pp. 88, 91, 531 – 533).

Based on documentation that human food chain species are fished for consumption within Livingston Creek, a human food chain fishery was correctly identifi ed as a target in the HRS documentation record at proposal. This fishery was correctly identified and used for scoring human food chain individual and population.

This comment has no effect on the HRS site score or the decision to place the Site on the NPL.

3.11.2 Zone of Contamination

Comment: McGrath North questioned whether sediment sample WC-006-SD, which has concentrations higher than those in the swamp area close to the source area, is an observed release from the Wright Chemical site. McGrath North questioned the origin of the contamination at sample location WC-006-SD and whether it is part of the zone of cont amination at the Wright Chemical site.

Response: The zone of contamination for surface water was identified in accordance with the HRS and the targets within that zone were properly identifie d as actually contaminated. However, there was an error in the description of the Level II zone of c ontamination under the title "Food Chain Individual." The text of this section was revised, in the HRS documen tation record at promulgation, to reflect that the
Level II zone of contamination exte nds to sample WC-006-SD.

Instructions for delineating the zone of contaminati on for a human food chain fishery are located in HRS Section 4.1.1.1, Definition of hazardous substance migr ation path for overland/flood migration

component. It states that:

The hazardous substance migration path includes both the overland segment and the inwater segment that hazardous substances would take as they migrate away from sources
at the site:

• Begin the overland segment at the source and proceed downgradient to the probable point of entry to surface water.

• Begin the in-water segment at this probable point of entry.

- For rivers, continue the in-water segment in the direction of flow (including any tidal flows) for the distance established by the target
distance limit....

26Wright Chemical Corporation Listing Support Document March 2011

HRS Section 4.1.1.2, Target distance limit, states:

[t]he target distance limit defines the maximum distance over which targets are considered in evaluating the site. Determ ine a separate target distance limit for each
watershed as follows:

. . .

• If there is an observed release from the site to the surface water in the watershed that is based on sampling, begin measuring the target distance limit for the watershed at the probable point of entry; extend the targ et distance limit either for 15 miles along the surface water or to the most distant sample point that meets the criteria for an observed release to that watershed, whichever is greater.

In evaluating the site, include only surface wate r targets (for example, intakes, fisheries, sensitive environments) that are within or contiguous to the hazardous substance migration path and located, partially or wholly, at or between the probable point of entry and the target distance limit applicable to the watershed:

. . .

• Determine whether targets within or contiguous to the hazardous substance migration path are subject to actual or potential contamination as follows:

- If a target is located, partially or wholly , either at or between the probable point of entry and any sampling point that meets the criteria for an observed release to the watershed or at a point that meets the criteria for an observed release by direct observation, evaluate that target as subject to actual contamination, except as otherwise specified for fisheries in se ction 4.1.3.3 and for wetlands in section 4.1.4.3.1.1. If the actual contamination is based on direct observation, assign
Level II to the actual contamination. Ho wever, if the actual contamination is based on samples, determine whether the actual contamination is at Level I or Level II concentrations as specified in sections 4.1.2.3, 4.1.3.3, and 4.1.4.3.1.

- If a target is located, partially or wholly , within the target distance limit for the watershed, but not at or between the probable point of entry and any sampling point that meets the criteria for an observed release to the watershed, nor at a point that meets the criteria for an observed release by direct observation, evaluate it as subject to potential contamination.

Thus, the HRS states to consider that targets are subj ect to actual contamination if they are between the probable point of entry (PPE) and the furthest downs tream sample that meets observed release criteria (regardless of whether or not there are samples between these points that do not meet the criteria). HRS Section 4.1.3.3, Human food chain threat-targets, identifies further requirements for determining a human food chain fishery within the zone of contamination:

Consider a fishery (or portion of a fishery) within the target distance limit of the watershed to be subject to actual human food chain contamination if any of the following apply:

• A hazardous substance having a bioaccumu lation potential factor value of 500 or greater is present either in an observed release by direct observation to the watershed or in a surface water or sediment sample from the watershed at a level that meets the criteria for an observed release to the watershed from the site, and at least a portion of the fishery is within the boundaries of the observed release

27Wright Chemical Corporation Listing Support Document March 2011

28 (that is, it is located either at the point of direct observation or at or between the probable point of entry and the most distant sampling point establishing the observed release).

• The fishery is closed, and a hazardous s ubstance for which the fishery has been
closed has been documented in an ob served release to the watershed from the site, and at least a portion of the fishery is within the boundaries of the observed
release.

• A hazardous substance is present in a tissu e sample from an essentially sessile, benthic, human food chain organism from the watershed at a level that meets the criteria for an observed release to the watershed from the site, and at least a portion of the fishery is within the boundaries of the observed release.

Page 36 of the HRS documentation record at proposal under the title, Food Chain Individual, stated:



### Level II contamination in Livingston Creek from the PPE downstream 250 feet to Sample WC-003-SD has been documented as part of a fishery. (Ref. 4, pp. 35, 70, 88, 531-533, Fig. 4).

Page 37 of the HRS documentation record at propos al under the title, Level II Concentrations, stated:

Arsenic, cadmium, copper, lead, and zinc c ontamination have been documented in source 1 and in sediment in the fishery. The leve l of contaminants is summarized below:

mg/kg WC-003-SD WC-013-SD WC-006-SD
Arsenic 31 J [17.8] 29 J [16.6] 320 J [183.9]
Cadmium 3.5 3.6 2.4 U, J Copper 190 J [155] 150 J [122] 770 J [631]
Lead 520 J** [360] 430 J** [300] 1200 J** [830]

Zinc 660 780 380

The HRS documentation record has been revised at promulgation to show that the Level II zone of contamination extends to sample WC-006-SD. Th e revision of the description of the zone of
contamination in the HRS documentation record at promulgation does not have an impact on the HRS score, as Level II concentrations were correctly sco red at proposal as extending to sample WC-006-SD.



## 4. Conclusion

The original HRS score for this site was 48.03. Based on the above responses to public comments, the site score remains unchanged. The final scores fo r the Wright Chemical Corporation site are:

Ground Water: NS
Surface Water: 96.06 Soil Exposure: NS Air Pathway: NS

HRS Score: 48.03