22004_Witherspoon Nursery_DM_20191114

DECISION MEMORANDUM
DATE: November 14, 2019
FROM: James Rudder & Sharon Eckard
TO: BF Assessment File
RE: Witherspoon Nursery
3312 and 3330 Watkins Road
Durham, Durham County
BF # 22004-18-032
Based on the following information, it has been determined that the above referenced
site, whose intended use is for no uses other than high -density residential, hotel,
institutional, retail, medical, office, associated parking, and subject to DEQ's prior
written approval, other commercial uses.
Introduction:
The Prospective Developer (PD) is LRC VII, LLC; originally the Brownfields Property
Application (BPA) included two Prospective Developers, LRC VII, LLC and Crowne at
501, LP; however, Crowne at 501, LP withdrew as the PD. The Brownfields Property
comprises originally comprised one parcel (PIN 0800-03-21-7363) totaling
approximately 8.0167 acres at the time the Brownfields Property Application (BPA) was
received and eligibility determined.
The Prospective Developer subsequently subdivided the Brownfields Property into two
parcels:
(1) Parcel 1 having PIN 0800-21-63-3681 comprised of 3.7008 acres with the
address of 3312 Watkins Road; and
(2) Parcel 2 having PIN 0800-21-83-6190 comprised of 4.3159 acres with the
address of 3330 Watkins Road.
LRC VII, LLC sold Parcel 1 of the Brownfields Property to Crowne at 501, LP on
September 5, 2018. Crowne at 501, LP is considered a follow-on owner of this portion
of the Brownfields Property by the Brownfields Program.
Redevelopment Plans:
The Brownfields Property redevelopment plans include high -density residential, hotel,
institutional, retail, medical, office, associated parking, and subject to DEQ's prior
written approval, other commercial uses. Crowne at 501, LP has started construction on
a five -story apartment complex on their portion of the Brownfields Property under an
approved Environmental Management Plan (EMP).
Witherspoon/22004-18-032/ 14Nov2019

Site History:
Prior to about 1938 through the 1960s, the Brownfields Property was undeveloped,
wooded, and primarily agricultural farmland. By 1955 the eastern portion of the
Brownfields Property was developed with a single family residence constructed with a
septic tank and drain field, with additional storage sheds and greenhouses added in the
1970s and 1980s. A single family residence was constructed on the northwest portion of
the Brownfields Property in the early 1960s (also constructed with a septic tank and drain
field) and was subsequently converted into commercial offices for the Witherspoon Rose
Culture company after they purchased the Brownfields Property in about 1961. A
pond/lagoon located on the eastern Brownfields Property boundary was used by
Witherspoon for irrigating their nursery. Each residence used a groundwater supply well
as their domestic water supply source, although no construction details of either on -site
well are available.
The Witherspoon Rose Culture (Witherspoon) company operated a plant nursery on the
Brownfields Property from 1961 to 2016, and reportedly sold garden supplies and
cultivated plants on the Property (i.e. nursery). LRC VII LLC purchased the Brownfields
Property from Witherspoon on March 29, 2016. Witherspoon continued to operate their
greenhouses for about one year after LRC VII LLC purchased the Brownfields Property
while Witherspoon was in the process of moving their nursery inventory to another
property. Over the course of Witherspoon's ownership and use of the land seven
greenhouses (at the time of Prospective Developer's purchase), five storage sheds, and
one compost area were constructed on the Brownfields Property. The storage sheds were
used for storage of seeds, plants, fertilizers, pesticides and other materials required by a
plant nursery, and the contents of the storage sheds varied over time.
One 280-gallon heating oil AST was located adjacent to the southwest corner of the
former residence used by Witherspoon as their administrative office building.
Assessment of soil adjacent to the AST reported total petroleum hydrocarbons as diesel
range organics (TPH-DRO) and total petroleum hydrocarbons as gasoline range organics
(TPH-GRO) concentrations of 270 milligrams per kilogram (mg/kg) and 100 mg/kg,
respectively. The AST was removed from the Brownfields Property on March 5, 2018;
prior to its removal, 68 gallons of oil and water were pumped from the AST. A total of
11.64 tons of soil were excavated from the area and transported to a NC -licensed off -site
facility for disposal. Confirmation sampling reported one soil sample collected close to
the southwest corner of the administrative building contained 1,600 mg/kg TPH-DRO
after the AST was removed.
The two on -site former residences were constructed adjacent to the western and eastern
property boundaries on the northern end of the Brownfields Property, and were
developed with on -site septic tanks and drain fields. Each former residence used an
adjacent groundwater supply well for their water supply and each water supply well was
located north of, and adjacent to, the residence that it served. The two water supply wells
and two former residential structures remain on the Brownfields Property, but are
scheduled to be demolished to make way for the redevelopment.
2
Witherspoon/22004-18-032/ 14Nov2019

Potential Receptors:
Potential receptors are: construction workers, on -site workers, future residents, visitors,
and trespassers.
Contaminated Media:
DEQ has evaluated data collected from the following media at the subject property: soil,
groundwater, surface water and sediment. DEQ relies on the following data to base its
conclusions regarding the subject property and its suitability for its intended reuse.
Soil
Terracon Consultants in their 2017 assessment drilled 22 soil borings and collected 35
soil samples from 0.0 to 0.5 feet, from 1 to 2 feet, 2 to 4 feet, and from 4 to 6 feet below
the ground surface (bgs). Soil samples were analyzed for herbicides (EPA Method
8151A), pesticides (EPA Method 8081B [organochlorine pesticides]) and the metals
arsenic, copper, and lead.
In January 2019, Hart & Hickman collected one soil sample from each of the two on -site
septic system drain fields (SB-1 [from 4 to 5 feet bgs] and SB-2 [from 6 to 8 feet bgs])
and each soil sample was chemically analyzed for volatile organic compounds (VOCs) by
EPA Method 8260B, semi -volatile organic compounds (SVOCs) by EPA Method 8270D,
and the eight RCRA metals.
Arsenic concentrations were reported to exceed NC Department of Environmental
Quality's Division of Waste Management's (DWM) Preliminary Soil Remediation Goals
(PSRGs) table (February 2018 version) concentration of 0.68 mg/kg in 34 soil samples
collected across the Brownfields Property ranging in depth of 0.5 to 6 feet bgs. The single
digit arsenic concentrations are believed to be representative of naturally -occurring
concentrations for soils in this area; however, the higher concentrations may be indicative
of impact to soil. These higher arsenic concentrations were reported in two samples at 23
milligrams per kilogram (mg/kg) and 26 mg/kg, both of which are below a site -specific
residential risk -based action level of 34 mg/kg averaged per half -acre. Additionally, see
DWM risk calculator analysis below.
One total petroleum hydrocarbon concentration (TPH) containing diesel rage organics
(DRO) was reported on the north side of the above ground heating oil storage tank (AST)
removal excavation immediately adjacent to the former Witherspoon Administration
building (former residence) on the northwestern portion of the Brownfields Property. The
TPH-DRO concentration of 1,600 mg/kg exceeded the current DWM UST Section action
level for TPH-DRO of 100 mg/kg in soil. However, the soil represented by this sample is
believed to have been excavated from this area of the Brownfields Property in late
October/early November 2019 during demolition of the existing office building in
accordance with the approved EMP. Confirmatory sample results are pending at the time
of this update; any exceedances will be addressed through the EMP process. A 15-cubic
yard stockpile was generated onsite from this soil and was sampled and chemically
analyzed. Those sample results are expected to become available within the next 30 days
Witherspoon/22004-18-032/ 14Nov2019

and will be used to confirm the removal of the contaminants from this area and identify
appropriate disposition of the excavated material.
Groundwater
In November 2015, the environmental consultant ATC installed two temporary
groundwater piezometers (B-4 and B-5) and collected groundwater samples from the two
on -site groundwater supply wells and two sumps at the Brownfields Property. Apparent
perched water conditions were encountered in piezometer B-5 where water was
encountered in clayey soils at a depth of 4.5 feet bgs, but the actual groundwater table
was below a depth of 25 feet bgs in B-5.
In January 2019, the environmental consultant Hart and Hickman installed three
temporary groundwater monitoring wells to depths of 25 feet. One was installed
downgradient from the former AST location on the northwestern portion of the
Brownfields Property (TMW-4), one was installed near the former location of ATC's
piezometer B-5 (TMW-2), and one was installed downgradient of the sumps located in
the central areas of the Brownfields Property (TMW-1). The groundwater table was not
encountered in the temporary groundwater monitoring wells after waiting a period of 48
hours.
Conclusions from the groundwater assessments are that the depth to groundwater beneath
the Brownfields Property exceeds 25 feet. Laboratory analyses of the groundwater
samples from the two on -site former residential supply wells and on -site sumps did not
contain herbicide, pesticide, or metals concentrations above State of North Carolina 2L
Groundwater Quality Standards (2L Standards). Perched water was encountered in
temporary well TMW-2, which appeared to be caused by the presence of a high content
of clay in the surficial and near -surface soils in this location.
Lagoon Surface Water and Sediment
Hart & Hickman personnel collected one surface water and one sediment sample from
two locations in the on -site lagoon. Each of the two surface water and two sediment
samples were chemically -analyzed for VOCs (EPA Method 8260B), SVOCs (EPA
Method 8270D), RCRA metals, herbicides (EPA Method 8151), organophosphorus
pesticides (EPA Method 8141B), organochlorine pesticides (EPA Method 8081B), and
nitrates (Standard Method 300.0). No surface water or lagoon sediment samples
contained compound concentrations above applicable NC 2B surface water standards nor
non-residential PSRGs screening levels.
Soil Vapor
Because no VOCs were reported to have been used on -site or reported in site soil, nor
were detected in the onsite water supply wells, sumps, or the septic drain field, and the
depth to groundwater exceeded 25 feet below the ground surface in previous assessments,
no soil vapor samples were collected.
4
Witherspoon/22004-18-032/ 14Nov2019

Sub -Slab Vapor
Because no volatile organic compounds were reported to have been used on -site or
reported in site soil, nor were detected in the onsite water supply wells and sumps, and
the depth to groundwater exceeded 25 feet below the ground surface in previous
assessments, no sub -slab soil vapor samples were collected.
Indoor Air
Because no volatile organic compounds were reported to have been used on -site or
reported in site soil, nor were detected in the onsite water supply wells and sumps, and
the depth to groundwater exceeded 25 feet below the ground surface in previous
assessments, no indoor air samples were collected.
Risk Calculations
Risk Calculations were performed using the DWM Risk Calculator (February 2018
version). For the purposes of looking at the site spatially, the site was evaluated as a
whole and was not subdivided into geographical subdivisions. The risk calculations
indicated the following based on available data, including the following media:
groundwater, soil, surface water, and sediment samples:
Summary of Risk Assessment Output
LU111111IFF
Version Date: February 2018
Basis: November 2017 EPA RSL Table
Site ID:
Exposure Unit ID:
PRIMARY CALCULATORS
Receptor
Pathway
CarcinogenicRisk
Hazardlndex
Risk exceeded`.
Resident
Soil Combined Pathways
7.6E-06
1.4E-01
NO
Groundwater Combined Pathways*
0.0E+00
0.0E+00
NO
Non -Residential Worker
Soil Combined Pathways
1.5E-06
1.0E-02
NO
Groundwater Combined Pathways*
0.0E+00
0.0E+00
NO
Construction Worker
Soil Combined Pathways
0.0E+00
0.0E+00
NO
User Defined
Soil Combined Pathways
4.2E-06
8.0E-02
NO
Surface Water Combined Pathways*
0.0E+00
0.0E+00
NO
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazardlndex
Risk exceeded?
Resident
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Soil Gas to Indoor Air
0.0E+00
0.0E+00
NO
Indoor Air
0.0E+00
0.0E+00
NO
Non -Residential Worker
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Soil Gas to Indoor Air
0.0E+00
0.0E+00
NO
Indoor Air
0.0E+00
0.0E+00
NO
Red shading LICR> 1 E-04 or HI> 1.
LICR = Lifetime Incremental Cancer Risk
HI = Hazard Index
*Risk calculations before soil excavation completed in area. Awaiting cyclohexane, hexane, and heptane lab results.
5
Witherspoon/22004-18-032/ 14Nov2019

Based on the Risk Calculations above for the maximum reported concentrations risk for
residential development and to construction workers is less than 1.0E-4 for Cancer Risk
and less than 1.0 for Hazard Index, and so the risk does not pose a concern for the
development proposed for the Brownfields Property. Note that the TPH value of 1,600
mg/kg was included in this risk calculator, but the soil represented by this value has since
been removed from the Brownfields Property; therefore, the calculated risk values are
believed to be even less presently than that accounted for in the above risk calculator.
Required Land Use Restrictions:
In addition to the land redevelopment use statement and accompanying definitions and
standard land use restrictions in each BFA, the following concepts will be addressed by
land use restrictions in the BFA:
1. Physical development occurs in accordance with an approved site -specific
Environmental Management Plan.
2. Property may not be used for child or adult care or schools.
3. Groundwater may not be used.
4. No activity may disturb soil except in specified situations.
5. Imported/exported soil must be evaluated before transporting onto or off of
the Brownfields Property.
6. No enclosed building may be constructed on the Brownfields Property until
vapor intrusion mitigation requirements are satisfied.
7. None of the documented contaminants can be stored or used on the
Brownfields Property except in de minimus quantities or under certain
conditions.
8. A Land Use Restriction Update must be filed during January of each year
after the Brownfields Agreement is signed and recorded.
Based on the site -specific data provided to the Brownfield program, the site reuse is
suitable for the site as long as the agreed upon land use restrictions in the BFA are abided
by.
6
Witherspoon/22004-18-032/ 14Nov2019