NCD003162542_Badin Business Park_Corrective Action_20221114

Badin Business Park LLC c/o Alcoa Corporation 201 Isabella Street Suite 500 Pittsburgh, PA 15212-5858 USA Tel: [phone]

November 14, 2022

Robert C. McDaniel Facility Management Branch
Hazardous Waste Section
North Carolina Department of Environmental Quality 217 West Jones Street
Raleigh, North Carolina 27603
Re: Response to North Carolina DEQ Comments Badin Business Park, Badin, North Carolina (NCD 003 162 542)
Mr. McDaniel:
Per your October 12, 2022 letter request, please see the attached responses to DEQ comments on the Former Ball Field Area Screening Level Ecological Risk Assessment and the Screening Level Ecological Risk Assessment Report for the Alcoa Badin Landfill.
Additionally, Badin Business Park, LLC (BBP) will address outstanding problem formulation elements to support the determination that no unacceptable ecological risk is present at the Former
Ball Field that would require further investigation or remediation. That submittal will occur concurrently with a Baseline Ecological Risk Assessment (BERA) Work Plan for the Alcoa/Badin Landfill as discussed in the attached responses.
Please contact Jason Mibroda at [phone] with any questions you may have.

Sincerely,

Ronald M. Morosky
Director, Corporate Remediation and Technology
cc: Adam Ulishney (NCDEQ) John E. Johnston (USEPA) Kim T. Caulk (NCDEQ) Robyn L Gross (Alcoa) Rose Pruitt (NCDEQ) Jason Mibroda (Alcoa) Sarah Cook (Toeroek)
Brian Bastek (USEPA)
Robert C. McDaniel Response to NCDEQ Comments Badin Business Park, Badin, North Carolina
November 14, 2022
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Table – Response to Comments on the Screening Level Ecological Risk Assessment Report for the Alcoa/Badin Landfill
Comments BBP Response
General Comments
General Comment 1. Revise the Screening Level Ecological Risk
Assessment Report for the Alcoa/Badin Landfill, dated December 2021
(Landfill SLERA) to:
1. present a comprehensive CSM;
2. present the basis for the chemicals of potential concern (COPCs),
and identify which sample locations were included in the SLERA
data set;
3. develop a data gaps section that addresses data gaps in the
nature and extent of sampling;
4. identify major uncertainties in the sample coverage and/or data
quality issues; and 5. present a basis for Step 3 of the ecological risk assessment
process.
The comments received on the SLERA for the Alcoa/Badin Landfill (ABL)
will be addressed in the Baseline Ecological Risk Assessment Work Plan
(BERA Work Plan) being developed for the ABL. A preliminary Problem
Formulation [Step 3 of Ecological Risk Assessment Guidance for Superfund
(ERAGS)] will be presented in the BERA Work Plan that will include:
• A comprehensive ecological conceptual site model (ECSM)
• A COPC refinement to identify focal constituents for the BERA
investigation
• A figure depicting the sampling locations of datasets included in
the SLERA
• An analysis that identifies major uncertainties in the SLERA and
assesses data gaps related to the adequacy and quality of sample
datasets to satisfy BERA data quality objectives (DQOs)
• Assessment endpoints and measurement endpoints that will be
evaluated in the BERA.
The preliminary Problem Formulation will provide the basis for identifying
additional data collection to address identified data gaps.
General Comment 2. Provide a figure or figures which depict the locations
of all samples evaluated in the Landfill SLERA to demonstrate that sample
coverage in the areas of interest (both source areas and those areas that
reflect potential COPC transport or accumulation) is sufficient.
A figure depicting the locations of samples evaluated in the SLERA will be
presented in the BERA Work Plan.
Robert C. McDaniel Response to NCDEQ Comments Badin Business Park, Badin, North Carolina
November 14, 2022
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Comments BBP Response
General Comment 3. There is a 2008 statewide fish consumption advisory
in place for mercury, and as of February 2009, a fish consumption advisory
is in place for Badin Lake (both Stanly and Montgomery counties) for
polychlorinated biphenyls (PCBs). It is unclear if contamination from the
Alcoa/Badin Landfill (also known as Solid Waste Management Unit No. 2)
and the adjacent Little Mountain Creek and floodplain (the Site) could
contribute to the need for the fish advisories. Address the potential for
the Site to contribute COPCs to fishable water bodies included in the fish
consumption advisories.
The preliminary Problem Formulation that will be presented in the BERA
Work Plan will include an updated summary of the hydrological
conceptual site model (HCSM) to identify potential sources and migration
pathways to Little Mountain Creek. The preliminary Problem Formulation
will also include an ECSM to identify potential ecological receptors and
exposure pathways within Little Mountain Creek. The ECSM will be used
to evaluate the potential for COPC bioaccumulation and biomagnification.
This evaluation will be used to inform the data gaps analysis and support
the development of a sampling scope to address identified data gaps.
General Comment 4. The SLERA does not include a lines–of–evidence
analysis for each exposure area, including a comparison of Site data to
background concentrations, analysis of frequency of detection of COPCs,
and an analysis of the applicability of the ecological screening
levels…Revise the Landfill SLERA to include a lines–of–evidence analysis
for each exposure area.
The preliminary Problem Formulation in the BERA Work Plan will include a
review of the SLERA data to inform the conceptualization of each exposure
area in the refined ECSM. The data review will include an assessment of
multiple lines of evidence, including an assessment of concentrations
relative to representative background data, frequency of detection, and
magnitude of exceedance of relevant ecological screening values.
Specific Comments
Specific Comment 1. There is no recommendation regarding what
species/habitats should be considered in the next phases of the ecological
risk assessment process. Identify if special status species or critical
habitats could be impacted by Site contaminants and if additional
sampling is needed to address risk to these species or habitats.
The preliminary Problem Formulation presented in the BERA Work Plan
will include a refined ECSM that will define exposure areas to be evaluated
in the BERA. The refined ECSM will identify relevant and representative
ecological receptors to be further evaluated within each exposure area in
the BERA. The selection of relevant and representative receptors will
include an evaluation of potential for special status species to be exposed
within defined exposure areas. The potential for a special status species
to be present within an exposure area will be evaluated based on a review
of the habitat suitability of the exposure area and species-specific habitat
requirements.
Specific Comment 2. Revise the Landfill SLERA to explain how operations
at and/or releases from the landfill and electrical substations resulted in
contamination of soil, surface water, and sediment. In addition, clarify if
there are any on-going sources of contamination.
The preliminary Problem Formulation presented in the BERA Work Plan
will include a summary of an updated HCSM that defines sources and
conceptual migration pathways to exposure areas based on historical and
current conditions. The updated HCSM evaluates conceptual migration
pathways based on site conditions following the implementation of
groundwater remedial actions.
Robert C. McDaniel Response to NCDEQ Comments Badin Business Park, Badin, North Carolina
November 14, 2022
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Comments BBP Response
Specific Comment 3. …there is no clear presentation of all COPCs
expected based on the Site history. Revise the Landfill SLERA to include a
comprehensive discussion of COPCs based on the Site history and past
investigations.
The preliminary Problem Formulation that will be presented in the BERA
Work Plan will identify COPCs associated with site operations based on
previous investigations. The preliminary Problem Formulation will also
include a COPC refinement, consistent with Step 3 of ERAGS, to focus
BERA investigations on primary COPCs associated with site operations that
are likely to drive the risk analysis in the BERA.
Specific Comment 4. Revise Section 2.2 to address each of these issues by
including a discussion of the sources, nature, and extent of groundwater
contamination. In addition, describe the hydrogeology of the Site and
evaluate the mechanism of groundwater-to-surface water discharge.
Finally, identify any data gaps and uncertainties in the understanding of
the hydrogeology of the Site.
As indicated in the response to Specific Comment 2, the preliminary
Problem Formulation presented in the BERA Work Plan will include a
summary of an updated HCSM that defines sources and conceptual
migration pathways to exposure areas based on historical and current
conditions. The updated HCSM evaluates conceptual migration pathways
based on site conditions following the implementation of groundwater
remedial actions.
Specific Comment 5. Add a discussion in Section 2.3.1 that clearly
identifies the areas being investigated in the SLERA and which receptors
are relevant in the various exposure areas.
As stated in the response to Specific Comment 1, the preliminary Problem
Formulation presented in the BERA Work Plan will include a refined ECSM
that will define exposure areas and representative receptors to be
evaluated in the BERA. A figure will be presented in the BERA Work Plan
depicting the extent of define exposure areas.
Specific Comment 6. Revise the text to more accurately reflect the
number of samples evaluated in the SLERA.
In addition to depicting the location of sampling stations, the preliminary
Problem Formulation will review the data presented in the SLERA and
provide a summary of data available for each exposure medium within
each exposure area.
Specific Comment 7. Expand Section 3.3.1 to evaluate the quality of the
data, spatial coverage, representativeness of the data set for ecological
exposure, and identify data inadequacies.
As stated in the response to General Comment 1, the preliminary Problem
Formulation will include an analysis that identifies major uncertainties in
the SLERA and assesses data gaps related to the adequacy, spatial
coverage, and quality of sample datasets to satisfy BERA DQOs.
Robert C. McDaniel Response to NCDEQ Comments Badin Business Park, Badin, North Carolina
November 14, 2022
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Comments BBP Response
Specific Comment 8. The Scientific Management Decision Point (SMDP)
should be expanded to recommend the next steps in the ecological risk
assessment process. This could be organized by exposure area and could
include recommendations such as additional sampling and analysis for a
limited COPC list, and further evaluating if protected species should be
considered in the next phase of the risk assessment. Expand the SMDP to
include recommendations for the Step 3 ecological risk assessment by
exposure area.
As stated in the response to General Comment 1, a preliminary Problem
Formulation, consistent with Step 3 ERAGS will be presented in the BERA
Work Plan.
Specific Comment 9. Revise the Landfill SLERA to discuss the derivation of
the total PCB concentrations in sediment, surface water, and
groundwater.
The calculation of total PCB concentrations will be discussed in the
preliminary Problem Formulation presented in the BERA Work Plan as part
of the SLERA data review. The discussion of total PCB calculations will also
include a discussion of the uncertainties in assumptions associated with
total PCB calculations, specifically the treatment on non-detected Aroclors
or congeners in the total PCB calculation.
Specific Comment 10. Revise the Landfill SLERA to include an analysis of
the PCB Aroclors and congener data, and further develop the CSM specific
to PCBs (i.e., evaluate the source(s), transport mechanisms, and
understanding of concentrations in the exposure areas). As part of this,
ensure each of these issues is addressed:
1. it is unclear what the congener analysis indicates regarding how
the PCBs are weathering;
2. it is unclear if dioxin-like congeners are present;
3. it is unclear if there is a potential transport mechanism for PCBs
to surface water bodies where they can accumulate in biota;
4. no discussion on the solubility of PCBs in water is presented;
5. it is unclear if the substations represent on-going sources of PCB
contamination; and,
6. it is unclear if total PCB data should be discussed in Section 3.1.3,
Summed Concentrations.
The preliminary Problem Formulation presented in the BERA Work Plan
will include a review of existing PCB data and an evaluation of PCB
sources, migration pathways, and an assessment of bioaccumulation and
biomagnification potential, as stated in the response to General Comment
3.