HomeMy WebLinkAbout7601_RandolphCountyMSWLF_August2024AppdxIIReductionRqst_FID1894497_20240829
August 29, 2024
Ervin Lane
Compliance Hydrogeologist
North Carolina Department of Environmental Quality
Division of Waste Management - Solid Waste Section
1646 Mail Service Center
Raleigh, North Carolina 27699-1646
Via email: ervin.lane@deq.nc.gov
RE: Randolph County Landfill
Permit Number 76-01
Request to Reduce Appendix II Monitoring Requirements
Project No. 2241481
Dear Mr. Lane:
On behalf of Waste Management of Carolinas, Inc. (WM) and Randolph County, LaBella Associates
(LaBella) is submitting this request to reduce Appendix II monitoring requirements for the closed
Randolph County Landfill, Permit #76-01. This request includes removing some previously detected
analytes from the facility’s Appendix II Detects List and to remove some analyses from the annual full
Appendix II list.
Randolph County operated a sanitary municipal solid waste (MSW) landfill at this site from 1973 to
1985, which is regulated under NCAC Title 15A, Chapter 13, Sub-Chapter .0500 (15A NCAC
13B.0500). A second landfill was in operation from 1985 to December 31, 1997, and is regulated
under 15A NCAC 13B.1630. In response to exceedances of groundwater protection standards (GPS)
for volatile organic compounds (VOCs) in site groundwater samples, the facility entered Assessment
Monitoring in 1996. A Corrective Action Plan (CAP) was submitted to the North Carolina Department
of Environmental Quality (NCDEQ) on July 31, 2015, and approved on September 10, 2015. The CAP
implemented Monitored Natural Attenuation (MNA) as the remedy for the site.
The current compliance groundwater monitoring network at the facility consists of one upgradient well
(MW-5), and five downgradient wells (MW-6, MW-7, MW-8, MW-9, and MW 10S). These wells are
currently sampled under the Assessment Monitoring program for the full NC Appendix II list of analytes
during the spring semiannual sampling event and for the NC Appendix I list plus previously detected
Appendix II analytes during the fall semiannual sampling event.
Historically, the following Appendix II analytes have been detected at least once in at least one
monitoring well at the Randolph County Landfill: mercury, tin, sulfide, dichlorodifluoromethane,
naphthalene, phenol, bis(2-ethylhexyl)phthalate, di-n-butylphthalate, diethylphthalate, alpha-BHC,
beta-BHC, delta-BHC, gamma-BHC, dieldrin, endosulfan-II, endosulfan sulfate, endrin, and dinoseb.
The following is a discussion of the historical detections of each of these analytes based on available
information from previous reports and historical data provided by NCDEQ.
Appendix II Inorganics:
Mercury was detected in MW-9 in April 2004 [(3.8 micrograms per liter (µg/L)], April 2005 (1.4
µg/L), and April 2006 (2.0 µg/L) at concentrations above the GPS; however, it has been mostly
non-detect since then except for two estimated (J-flagged) detections in October 2017 and
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October 2022. It has not been detected in MW-9 in the last three sampling events. Mercury
was also detected at a concentration below the GPS in April 2026 in MW-10S (0.272 µg/L);
however, it has not been detected in MW-10S since then. Mercury has never been detected
in any other compliance monitoring well.
Tin has been detected sporadically in most of the compliance monitoring wells including the
upgradient background well (MW-5). In April 2001 and April 2002, tin was detected at high
concentrations (163-414 µg/L) in all the compliance monitoring wells, with the highest
concentrations in the facility background well (MW-5). There were subsequent high detections
in MW-5 in April 2003 and April 2004. Since then, there have only been estimated (J-flagged)
detections, with the highest concentrations still in MW-5. One exception is a suspect detection
of tin in MW-9 (14.5 µg/L) in May 2021; however, this sample was rerun by the laboratory due
to quality control issues and the rerun result was non-detect. Other than the suspect May 2021
detection, tin has not been detected in any well since May 2018.
Sulfide was detected in MW-1 and MW-6 a few times between April 2009 and April 2014, all
with estimated concentrations ranging from 0.018 to 0.16 µg/L; however, it has not been
detected in any well since April 2015.
Cyanide has never been detected in any well.
Appendix II Volatiles (EPA Method 8260)
Dichlorodifluoromethane has been detected sporadically, most recently in May 2023 at 1.18
µg/L in MW-10S; however, it has not been detected in any well other than MW-10S since
October 2015.
Appendix II Semivolatiles (EPA Method 8270)
Naphthalene was detected once in MW-1 (0.40 J µg/L) in October 2007. It has not been
detected in any well since then.
Phenol was detected twice in MW-1 in April 2013 (3.2 J µg/L) and April 2014 (4.4 J µg/L);
however, it has not been detected since then.
Bis(2-ethylhexyl)phthalate has not been detected in any well since April 2005, except for a
blank-qualified detection in MW-1 (7.2 µg/L) in April 2012. The previous most recent detection
was in MW-6 (36 µg/L) in April 2005.
Di-n-butylphthalate has had one blank-qualified detection in MW-6 (1.5 µg/L) in April 2012. It
has not been detected in any well since then.
Diethylphthalate has not been detected in any well since October 2014, except for a blank-
qualified detection in MW-7 (24 µg/L) in April 2019, which was rerun by the laboratory and the
result of the rerun was non-detect. Between April 2008 and October 2014, it had been
detected in every compliance well at least once, including the background well (MW-5);
however, the only quantified detection was in MW-6 (23 µg/L) in April 2014.
3 & 4-Methylphenol had several detections in MW-1 between April 2009 and October 2014
ranging from 3.4J to 14 µg/L; however, it has not been detected in any well since October
2014.
Appendix II Pesticides (EPA Method 8081)
Alpha-BHC was detected once in MW-1 (0.378 µg/L) in April 2007. It has not been detected
in any well since then.
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Beta-BHC was detected once in MW-1 (0.27 µg/L) in April 2005. It has not been detected in
any well since then.
Delta-BHC was detected once in MW-8 (0.059 µg/L) in April 2002. It has not been detected
in any well since then.
Gamma-BHC was detected once in MW-1 (0.102 µg/L) in April 2005. It has not been detected
in any well since then.
Dieldrin was detected once in MW-9 (0.15 µg/L) in April 2001. It has not been detected in any
well since then.
Endosulfan II was detected once in MW-7 (0.14 µg/L) in April 2001. It has not been detected
in any well since then.
Endosulfan sulfate was detected once in MW-9 (0.11 µg/L) in April 2001. It has not been
detected in any well since then.
Endrin was detected once in MW-7 (0.16 µg/L) in April 2001. It has not been detected in any
well since then.
Appendix II Herbicides (EPA Method 8151)
Dinoseb was detected once in MW-7 (2.23 µg/L) in April 2001. It has not been detected in
any well since then.
Appendix II PCBs (EPA Method 8082)
There have never been any detections of any PCBs in any well.
Based on the above information, the only Appendix II detected constituents in recent sampling events
(2015 or later) have been mercury, tin, and dichlorodifluoromethane. We recommend that only these
three constituents be included in the Appendix II detects list for the facility beginning with the upcoming
fall 2024 monitoring event.
The only historical detections of pesticides or herbicides at this facility were isolated, one-time
detections, and there have been no detected pesticides or herbicides since April 2007. Also, there
have never been any detections of PCBs or cyanide at this facility since it entered Assessment
Monitoring in 1996. We recommend that cyanide, pesticides, herbicides, and PCBs be removed from
the required Assessment Monitoring Requirements for this facility. Beginning with the spring 2025
sampling event, the facility’s annual Appendix II event will include Appendix II metals, sulfide, Appendix
II volatile organic compounds, and Appendix II semivolatile organic compounds.
If LaBella can provide any additional information, please contact me at (336) 323-0092. Thank you.
Respectfully submitted,
LaBella Associates
Van Burbach, Ph.D., P.G.
Sr. Technical Geologist
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cc: Kyle Mertens – WM
Mike McFeeley – WM
Seth Ramaley, PG – WM
Amanda Fairley - WM
Paxton Arthurs, PE – Randolph County Public Works