4302_DunnErwinLCID_LeachateAssessmentReport_DIN26775_20160912

September 12, 2016

Mr. Ervin Lane
NCDEQ - Division of Waste Management
1646 Mail Service Center
Raleigh, North Carolina 27699

RE: Leachate Release Results
Harnett County Dunn Erwin Landfill (SWS Permit No. 43-02)
Dunn, North Carolina

Dear Mr. Lane:

Smith Gardner, Inc. (S+G) on behalf of Harnett County is pleased to present this brief letter
report summarizing the Leachate Response Investigation at the Harnett County Dunn Erwin
Landfill (Permit No. 43-02). S+G followed the approved Leachate Seep Response Plan
related to the NOV issued June 16, 2016 regarding violations observed during inspections
performed June 8, 2016.

Soil Sample Collection and Analysis

S+G personnel mobilized to the site on July 7, 2016, to collect soil samples from the flow path
of the leachate release. The flow path was confirmed in the field by field & site personnel
prior to sampling. To evaluate soil quality within the flow path, S+G collected a total of three
discreet grab samples; one sample, SS-1, was collected near the source of the release, a
second sample, SS-2, was collected in the flow path and the third sample, SS-3, was
collected where the leachate flow ended. Due to the naturally occurring inorganic metals in
the soils of North Carolina, S+G also collected a background sample, BG-1, upgradient and
away from the leachate flow path to evaluate the concentrations of naturally occurring
constituents. A water sample was collected from ponded water in the area of seep
origination. Sampling locations are shown on Figure 1.

Due to the location of a mulch stockpile adjacent to the background sampling location, S+G
personnel returned to the site on August 22nd to collect additional background samples
further from the LCID area. The secondary background samples are shown on Figure 1.

At each soil sample location S+G personnel collected samples at or near ground surface.
Samples were collected in the laboratory provided bottles and were shipped to the laboratory
under proper chain-of-custody (COC). Prism Laboratories, Inc., in Charlotte, NC, a North
Carolina certified laboratory (NC Certification No.: 402) performed the analysis. Collected
samples were analyzed for the Appendix I list of constituents (40 CFR 258 Appendix I).
Laboratory analysis is included as Attachment 1.

Mr. Lane
September 12, 2016
Page 2 of 3
Results were compared with the background sample and the NCDENR IHSB Preliminary Soil
Remediation Goals (PRGs). Sample results indicate that leachate did not impact the local
soils. The only volatile organic compound detected was acetone at low concentrations in
samples SS-1, BG-1, and BG-2. Methyl Iodide was also detected, but only in background
sample BG-2. Both these organic constituents are associated with laboratory cleaning and
are not believed to be due to landfill impact.

Cobalt (SS-1, and SS-2) and vanadium (SS-1, SS-2, SS-3, BG-1 and BG-2), were detected at
concentrations above their PRGs. Due to the elevated presence of vanadium in the
background samples the concentrations detected in the downgradient locations are not due
to landfill impact. Although cobalt was detected at slightly higher concentrations in
downgradient samples as compared to background, the difference is relatively minor.
Inorganic constituents are naturally occurring in North Carolina soils. Concentrations
between the background locations and other locations did not indicate a substantial
difference in inorganic concentrations for the analyzed parameters. Sample results are
presented in Table 1.

A water sample, WS-1, was also collected from standing water present near the SS-1
location. No organic samples were reported at concentrations above their 2L or
Groundwater Protection Standards. Inorganic constituents were primarily detected at non-
quantifiable concentrations or below their 2L or GWP Standards. Only antimony and cobalt
were detected above their GWP Standard. The cobalt concentration is similar to
concentrations seen in downgradient and background soil samples. The antimony
concentration is slightly elevated above the soil background antimony concentration. No
inorganic constituents were reported above their 2L Standard.

Summary and Conclusions

Inorganic constituents are naturally occurring in North Carolina soils. Concentrations of
inorganic constituents were generally consistent across the downgradient and background
soil samples. This Indicates the metals concentrations detected in the flow path are not due
to the leachate release. Low concentrations of inorganics in the water sample are consistent
with the soil samples for this report as well as semi-annual sampling performed at the
facility.

No organic constituents were reported at concentrations above the PRGs in soil samples;
and above 2L Standards for groundwater.

Based on the laboratory analysis, the leachate release does not appear to have adversely
affected the natural environment at the site. If you have any questions or require additional
information, please contact us at 919-828-0577 or by email below.

Mr. Lane
September 12, 2016
Page 3 of 3

Sincerely,
SMITH GARDNER, INC.

Madeline M. German, P.G. Joan A. Smyth, P.G.
Project Geologist Senior Hydrogeologist
[e-mail] [e-mail]

Attachments - Figure 1
Table 1
Lab Report

cc: Amanda Bader, P.E. – Harnett County
Randy Smith – Harnett County
Liz Patterson - NCDEQ

H:\Projects\Harnett County (NC)\Dunn-Erwin Landfill Facility\June 2016 Seep and Response\Leachate Release
Results_Harnett.docx
Figures

DRAWN:APPROVED:SCALE:DATE:PROJECT NO.:FIGURE NO.:FILE NAME:
PREPARED FOR:PREPARED BY:
SMITH
14 N. Boylan Avenue, Raleigh NC 27603
NC LIC. NO. C-0828 (ENGINEERING)
919.828.0577
GARDNER+
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© 2016 Smith Gardner, Inc.
DUNN-ERWIN LANDFILL FACILITY
LEACHATE SEEP SAMPLING LOCATIONS
HARNETT COUNTY
LILLINGTON, NORTH CAROLINA
T.R.S.J.A.S.AS SHOWN HARNET DE 13-2 1 HARNETT-A0105Sep 2016
Tables

Table 1
Detected Constituentsin Soil
Harnett County Dunn Erwin Landfill
July 7, and August 24, 2016
By: JS
Date: 9/12/16
H:\Projects\Harnett County (NC)\Dunn-Erwin Landfill Facility\June 2016 Seep and Response\Soil Results Table.xlsx
Detected Constituents
NCDENR IHSB
Preliminary Soil
Remediation
Goals (PRGs)
(mg/kg)
SS-1
(mg/kg dry)
SS-2
(mg/kg dry)
SS-3
(mg/kg dry)
BG-1
(mg/kg dry)
BG-2
(mg/kg dry)
Antimony BRL BRL BRL 0.17 J BRL
Arsenic 5.8 1.4 J 0.3 J 0.19 J 1.8 J 0.88 J
Barium 580 13 J 24 23 17 8.6 J
Beryllium 63 0.4 0.74 0.74 0.24 J 0.47
Chromium 360000 14 16 9.8 21 9.4
Cobalt 0.9 1.2 1.2 0.84 0.77 0.41
Copper 700 14 16 13 8.2 4.9
Lead 270 12 7.5 7.2 8.4 7.2
Nickel 130 2.9 1.6 1.3 4.8 0.63
Selenium 2.1 0.53 J 0.26 J BRL BRL BRL
Vanadium 6 29 55 24 96 30
Zinc 1200 6.5 J 6.9 J 4.1 J 9.8 J 3.5 J
Acetone 24 0.039 BRL BRL .0032 J 0.068
Methyl Iodide NA BRL BRL BRL 0.011 J 0.0049 J
NOTES:
J - Constituent detected but below the Reporting Limit (RL); therefore, the results is an estimated concentration.
Bold and Shaded - Concentration above listed standard
BRL = Concentration Below Reporting Limit
Data from Prism Laboratories, Inc., Work Order No: 6070141, dated 07/19/2016 and 6080422 dated 9/7/2016
IHSB Prelim. Soil Remediation Goals - NCDEQ Inactive Hazardous Sites Branch Preliminary Soil Remediation Goals for protection of
groundwater updated April 2016
Attachment 1

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