IMP Dissolved and Speciation Letter 8-12-19

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
LINDA CULPEPPER
Director
Paul Draovitch
Senior Vice President
Environmental, Health & Safety
Duke Energy
526 South Church Street
Mail Code EC3XP
Charlotte, North Carolina 28202
NORTH CAROLINA
Environmental Quality
August 12, 2019
Subject: Optimized Interim Monitoring Plans for 14 Duke Energy Facilities — Dissolved and
Speciation Requirements for Groundwater Sampling
Dear Mr. Draovitch:
On March 20, 2019, Duke Energy submitted proposed changes to the optimized Interim
Monitoring Plans (IMPS) for the respective coal ash facilities which were subsequently approved
by Department of Environmental Quality (DEQ) on April 4, 2019. These IMPs represented
agreements between the DEQ Regional Offices and Duke Energy's subject matter experts on
optimization of the groundwater monitoring programs at each facility. Each IMP included:
• a list of wells that shall be sampled quarterly,
• a list of wells to be sampled semi-annually,
• a list of wells where sampling will be discontinued,
• a list of wells to be abandoned,
• a list of Constituents of Interest (COIs) to be analyzed, and
• a list of COIs that will no longer be analyzed.
DEQ conducted a review of the optimized IMPS and related submittals to determine if the
necessary data are being collected to support remedial design for corrective action. Upon review
of recent submittals, DEQ staff have identified some discrepancies between the approved IMPS
and the actual data being collected and analyzed. For example, Duke Energy is no longer
collecting and analyzing dissolved samples at some wells for some COIs included in the IMP
sampling program.
Further review of the current groundwater monitoring program indicates speciation of groundwater
samples for metals has not been performed since 2015.
grerrww rirswr Ourp�
North Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street 1 1636 Mail Service Center I Raleigh, North Carolina 27699-1636
919.707.9000

Concentrations of total and dissolved constituents in combination with speciation analytes are
necessary in the development of geochemical models that will be used to understand contaminant
occurrence, oxidation state, and mobility under current (pre -closure) conditions and under the site
conditions that may occur during and after decanting, dewatering and source control measures
have been implemented. To address data needs, DEQ requests the following action to begin with
the next IMP Quarterly sampling event:
• Revise the existing IMPS if needed for each facility to ensure that dissolved samples are
collected and analyzed at wells along the geochemical model transects, selected
background locations, and selected downgradient wells that exhibit exceedances of the 15A
NCAC 02L .0202 groundwater quality standards.
• Collect total and dissolved samples and perform speciation for the following constituents
and oxidation states: Fe(II, III), Mn(II,III, IV), As(III,V), Cr(III,VI), Se (-II,IV,VI) at wells
along the geochemical model transects, selected background locations, and selected
downgradient wells that exhibit exceedances of the 15A NCAC 02L .0202 groundwater
quality standards.
If Duke Energy wishes to limit evaluation to select well locations, contact the appropriate DEQ
Regional Office hydrogeologist to determine appropriate wells.
DEQ may review the need for inclusion of dissolved and speciation analytes in IMPS once the
Corrective Action Plans have been reviewed and approved. Please note that any changes to the
IMPs require prior approval from the respective DEQ Regional Office.
Meetings to discuss the status and technical direction of the geochemical models, including
groundwater data needs identified in this correspondence, are requested. The immediate focus of
geochemical model review shall be the six facilities that have Corrective Action Plans due on
March 31, 2020. Other facilities that have recently completed excavation or are near completion
of excavation shall also be a high priority for review. Please begin scheduling meetings with the
DEQ Regional Hydrogeologist and the DEQ Central Office.
If you have any questions, please contact Steve Lanter (Central Office) at [phone] or the
appropriate DEQ Regional Office.
Sincerely, /
Jon Ri ard, Chief
Grou d Water Resources Section
cc: WQROS Regional Offices (electronic copy)
GWRS Central File Copy