3608_WMGastoniaTrans_SoilAssmtAppr_DIN27267_20170123

January 23, 2017

Sent Via Email – [e-mail]

Mr. Shawn Carroll
Environmental Protection Manager
Waste Management
3920 River Road
Wilmington, NC 28411

Re: Soil Sampling and Analysis Report
Gastonia Transfer Station
Permit ID # 3608-Transfer-1993
Gaston County
DIN 27267

Dear Mr. Carroll:

The Solid Waste Section (Section) has reviewed the Soil Sampling and Analysis report (DIN 27265) for the
Gastonia Transfer Station prepared by Golder Associates NC, Inc. (Golder). Leachate was observed leaving
loaded trailers and flowing across the parking lot to a grassy area during an October 12, 2016 compliance
inspection. The Section issued a notice of violation on November 2, 2016 requiring Waste Management to
submit a soil sampling plan to determine potential leachate impact. Golder submitted a soil sampling plan
on November 17, 2016 that was approved by the Section on November 21, 2016. Golder proposed to
collect two background soil samples, two samples from the area where leaks were observed from the trailers,
one sample from the point of confluence near the parking area, and the last sample from a location
downgradient of a drainage feature.

Golder collected soil samples on November 22, 2017 in accordance with the sampling plan. Soil sample
concentrations were compared to the NC DEQ Inactive Hazardous Sites Preliminary Residential Health-
Based Soil Remediation Goals, Preliminary Industrial Health-Based Soil Remediation Goals, and
Protection of Groundwater Remediation Goals. Arsenic was reported at concentrations above the
remediation goals in all samples except one of the background soil samples. Cobalt, selenium, vanadium,
and phosphours were present at concentrations greater than one or more of the remedial goals in various
samples. Volatile organic compound constituents acetone and 2-Butanone were reported at concentrations
below the remediation goals in the soil samples collected near the trailers.

The soil sample results indicated that the constituent concentrations in the background samples were similar
to those reported from the impacted area with the exception of arsenic. Golder presented United States
Geological Survey local soil concentration data for cobalt selenium, vanadium, and phosphorus to further
demonstrate the presence of those constituents at naturally occurring concentrations. Golder concluded that
additional assessment related to those constituents was not necessary since they are most likely to be
naturally occuring. No additional action was also recommended for acetone and 2-Butanone since those

concentrations were reported below the remediation goals. Due to the elevated arsenic concentrations in
the samples collected from the trailer and the area of confluence, Golder concluded that there could be
residual impact from the leachate release. Golder proposes to excavate the area where the trailer and
confluence samples were collected down to a maximum depth of four feet below ground surface.
Confirmatory samples will be collected and analyzed prior to backfilling the excavation with clean soil.

The Section approves of this recommendation and Waste Management should submit a proposed schedule
for soil excavation and confirmatory sampling within 30 days. 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 cooperation in this matter.

Sincerely,

Ervin Lane
Compliance Hydrogeologist
Solid Waste Section

cc: David Reedy II, P.G., Golder Associates NC, Inc.
Jason Watkins, Field Operations Branch Head – Solid Waste Section
Deb Aja, Western District Supervisor – Solid Waste Section
Kim Sue, Environmental Senior Specialist – Solid Waste Section
Jessica Montie, Compliance Officer – Solid Waste Section