9809-CDLF_AssmtMonWrkplnAppr_DIN27368_20170209

February 9, 2017

Sent Via Email - [e-mail]

Andy Davis
Wilson County Solid Waste Services Director
P.O. Box 1728
Wilson, NC 27894

Re: Assessment Monitoring Workplan Approval
Westside C&D Facility, Permit #98-09
DIN 27368

Dear Mr. Davis,

The Solid Waste Section (Section) has completed a review of the Assessment Monitoring
Workplan (DIN 27367) submitted on behalf of Wilson County by Babb and Associates,
P.A.(Babb). An assessment workplan was required per an October 14, 2016 correspondence from
the Section due to monitoring well GMW-3 groundwater samples exceeding the standards
established in 15A NCAC 02L .0202 (2L Standards). 1,2-dichloropropane is the constituent of
concern that was reported at concentrations above the 2L Standard during the October 2015 and
April 2016 groundwater monitoring events. Appendix II monitoring was initiated during the
November 2016 groundwater monitoring event and 1,2-dichloropropane concentrations exceeded
the 2L Standards for the third consecutive event.

Babb has proposed to conduct the assessment in two possible phases. The first proposed phase
involves collecting soil in the vicinity of GMW-3 and soil from the Tucker Farm. Three soil
samples are proposed to be collected near GMW-3 at depths ranging from 12”-18” below ground
surface. Two samples will be collected from Tucker Farm at similar depths. According to Babb,
1,2-dichloropropane is a potential soil fumigant constituent used for nematode control in farming
operations. Soil from Tucker Farm was used as borrow material during the Westide CDLF’s
construction, so the results from those soil samples could indicate if the Tucker Farm soils are a
potential contaminant source. If 1,2-dichloropropane is detected in the soil samples, Babb
proposes to submit an alternate source demonstration to address the 2L Standard exceedance. If
1,2-dichloropropane is not reported in the soil samples, Babb proposes to construct a groundwater
monitoring well downgradient of GMW-3 to define the lateral extent of groundwater
contamination.

The Section approves of the phased approach presented by Babb and the facility may proceed with
the assessment in accordance with the proposed schedule. Please contact me at [phone] or

by e-mail at [e-mail] if you have any questions or concerns regarding this letter.
Thank you in advance for your anticipated cooperation with this matter.

Sincerely,

Ervin Lane
Compliance Hydrogeologist
Solid Waste Section

cc sent via email: Gary D. Babb, P.G., Babb & Associates, P.A.
Jason Watkins, Field Operations Branch Head
Ed Mussler, P.E., Permitting Branch Head
Ming Chao, P.E., Permitting Engineer
Christine Ritter, Permitting Hydrogeologist
Drew Hammonds, Eastern District Supervisor
John College, Environmental Senior Specialist