HomeMy WebLinkAboutDEQ - Discovery of Oil Film in Groundwater Montana Department of
EmRONMENTAL QUALITY Brian Schweitzer,Governor
P.O. Box 200901 Helena, MT 59620-0901 ..4AQ6a.34.41.-1544.._!.___www.deq.mt.gov
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August 25, 2010 Lu
AUG 2 6 2010 '
Kenneth E. Olson, Jr.
Mayor, City of Laurel CITY OF LAiTEL
P.O. Box 10
Laurel, MT 59044
Subject: Discovery of Oil Film in Groundwater at the City of Laurel Wastewater Treatment
Plant, Laurel, Montana
Dear Mayor Olson:
On March 31, 2010, the City of Laurel reported to the Department of Environmental Quality
(Department)that an oily film on groundwater had been discovered in a test pit on the site of the City's
wastewater treatment plant and in excavations on adjacent property owned by CHS Inc. (CHS). The
oily film was found during preparations for installation of a water line from the City's water plant to
the wastewater treatment plant. The City of Laurel and CHS worked together to coordinate treatment
and disposal of contaminated groundwater and oily film during dewatering of the excavation. The
Department appreciates these efforts.
CHS has supplied the Department with an assessment of the oily film found during the waterline
installation. As part of that assessment, laboratory results were provided for a groundwater sample
taken from the excavation on the City of Laurel property. The groundwater sample was tested using
two analytical methods, Volatile Petroleum Hydrocarbon (VPH) analysis and an Extractable Petroleum
Hydrocarbon (EPH) screening test. These methods were appropriate for an initial evaluation of the
oily film found in the excavation. The analytical results showed that volatile petroleum hydrocarbon
concentrations were below Montana's Tier 1 Risk-Based Corrective Action (RBCA) regulatory levels
for groundwater. However, analysis results from the EPH screening test were 2,020 µ/L Total
Extractable Hydrocarbon (TEH), a level which indicates further testing should be conducted.
After review of the analytical data, the Department has determined additional work is necessary to
investigate the source or sources, as well as the nature and extent of the potential contamination.
Because contamination on groundwater has been found up-gradient on Laurel Refinery property, the
Department is requiring that CHS conduct additional investigation and sampling to determine whether
the source of the potential contamination is from historical refinery activities.
As the Department has stated in previous correspondence with CHS and the City of Laurel, the source
or sources of contamination are unclear at this time. Should CHS determine the potential
contamination is not from the refinery, the Department will ask the City of Laurel to initiate an
investigation to determine whether the source of the potential contamination is from City activities.
Enforcement Division • Permitting&Compliance Division • Planning,Prevention&Assistance Division • Remediation Division
K. Olson
August 25,2010
Page 2 of 2
The Department will keep the City of Laurel informed of progress and would appreciate the City's
cooperation while CHS continues to investigate this issue. If you need assistance or have any
questions, please do not hesitate to contact me. My phone number is 406/444-2876 and my email
address is listed below.
Sincerely,
' 3
Rebecca Holmes
Environmental Science Specialist
Waste and Underground Tank Management Bureau
Permitting and Compliance Division
e-mail: rholmes@mt.gov
cc: Chad Anderson, DEQ Enforcement Division
Ron Nissen, CHS Inc., P.O. Box 909, Laurel, MT 59044-0909
Kurt Markegard, City of Laurel, P.O. Box 10, Laurel MT 59044
HW facility files: CHS Laurel Refinery— Spills #1
Montana Department of
�O 0!:
ETA UA TY Brian Schweitzer,Governor
N-WP.O. Box 200901 Helena, MT 59620-0901 (406) 444-2544 • www.deq.mt.gov
August 25, 2010 �t�D
Ron Nissen AUG 2 6 2010
Refinery EH &S Engineer
CHS Inc.
P.O. Box 909 CITY OF LAUREL
Laurel, MT 59044-0909
Subject: Discovery of Oil Film in Groundwater at the City of Laurel Wastewater Treatment
Plant, Laurel, Montana
Dear Mr. Nissen:
The Department of Environmental Quality (Department) has received your letter dated May 28, 2010
regarding the CHS response to oil film found on groundwater on CHS refinery property and the City of j
Laurel Wastewater Treatment Plant. CHS concluded no further corrective action was necessary based
on sampling results and upgradient monitoring results.
Upon review of the information provided b CHS, the Department has the following comments:
p P Y i
1. LNAPL was observed in the excavation at Site #1. The nearest monitoring wells are RT-40
and RT-39, cross-gradient and up-gradient respectively from the excavation. CHS states
that LNAPL has been present in the vicinity of monitoring well RT-39. From data provided
by CHS for its annual report, it appears LNAPL has not been observed in well RT-40, a
well installed to monitor dissolved-phase volatile organic constituents in the Southeast
Area.
The groundwater flow direction is southeast, towards the Yellowstone River. Site #1 is
approximately 500 feet from the river. In addition, Site #1 is adjacent to the Billings Bench
Water Association Canal. The Department is concerned that the canal or groundwater may
present a pathway to the Yellowstone River for contaminants. Due to the presence of
LNAPL in the excavation site, the monitoring gap between wells RT-30 and RT-40, and the
location of the irrigation canal, the Department is requiring a monitoring point be installed
in the area of the excavation site. Samples must be analyzed for volatile and semi-volatile
organics and metals.
2. Results of the Volatile Petroleum Hydrocarbon (VPH) analysis of the sample taken on the
City of Laurel property indicate volatile petroleum hydrocarbons are below Montana's Tier
1 Risk-Based Corrective Action (RBCA) groundwater risk-based screening levels and
standards. However, analysis results from the Extractable Petroleum Hydrocarbon (EPH)
screening test were 2,020 µ/L Total Extractable Hydrocarbon (TEH).
Enforcement Division • Permitting&Compliance Division • Planning,Prevention&Assistance Division • Remediation Division
R.Nissen
August 25,2010
Page 2 of 2
The EPH screening results indicate petroleum hydrocarbons were present in the sample
taken from Site #2. As noted in the Montana Tier 1 RBCA guidance for petroleum
releases, if the initial EPA screening results are greater than 1,000 ppb, EPH fractionation
may be required to determine levels of regulated petroleum hydrocarbons. However,
according to the information CHS provided, an EPH fractionation was not performed on the
City of Laurel sample.
LNAPL had been observed in the Site #1 excavation, well RT-39, and the Site #2
excavation. Results of the EPH screening test indicate presence of petroleum hydrocarbons
in the sample taken from the Site #2 excavation. The Department believes the EPH
analytical result of 2020 µ/L TEH indicates that a more detailed analysis is required before
CHS can conclude the LNAPL found in the Site #2 excavation did not originate from the
Laurel Refinery contamination. Testing procedures for groundwater samples must include
EPH fractionation, SW-846 Method 8270, and metals.
Investigations on the Laurel Refinery property have shown contamination on groundwater up-gradient
of the City of Laurel wastewater treatment plant. CHS must adequately determine whether the LNAPL
present on the City of Laurel property stems from activities at the Laurel Refinery and take appropriate
corrective measures if necessary, in accordance with it hazardous waste permit(MTHWP-02-02).
Should it be determined that the contamination originated all or in part from releases on.the City of
Laurel property, then the Department will require the City of Laurel to initiate an investigation to
determine whether the source of the contamination is from City activities.
By October 15,2010, please provide a work plan which details actions CHS will take to investigate
the extent and nature of the LNAPL discovered in the Site #1 and Site #2 excavations. The work plan
should include monitoring point locations, analyses to be performed, and a schedule.
If you need assistance or have any questions, please do not hesitate to contact me. My phone number
is 406/444-2876 and my email address is listed below.
Sincerely,
Rebecca Holmes
Environmental Science Specialist
Waste and Underground Tank Management Bureau
Permitting and Compliance Division
e-mail: rholmes@mt.gov
cc: Chad Anderson, DEQ Enforcement Division
Kenneth E. Olson, Jr., Mayor, City of Laurel, P.O. Box 10, Laurel, MT 59044
Ron Nissen, CHS Inc., P.O. Box 909, Laurel, MT 59044-0909
Kurt Markegard, City of Laurel, P.O. Box 10, Laurel MT 59044
HW facility files: CHS Laurel Refinery—Spills #1