DSHW-2018-001486 - 0901a068807bd340

DSHW-2018-001486 195 North 1950 West • Salt Lake City, UT Mailing Address: P.O. Box 144880 • Salt Lake City, UT 84114-4880 Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov Printed on 100% recycled paper
State of Utah
GARY R. HERBERT Governor
SPENCER J. COX
Lieutenant Governor
Department of
Environmental Quality
Alan Matheson Executive Director
DIVISION OF WASTE MANAGEMENT AND RADIATION CONTROL Scott T. Anderson Director
March 1, 2018
Kris Blauer, Manager Environmental Services
ATK Launch Systems – Promontory P.O. Box 707 Brigham City, UT 84302-0707
RE: Proposed Groundwater Exposure Units for Human Health and Ecological Risk Assessments UTD009081357
Dear Mr. Blauer:
The Division of Waste Management and Radiation Control has completed its review of ATK’s proposal dated January 10, 2018, identifying exposure units and monitoring wells to be used in the Human Health and Ecological Risk Assessments. Review comments are enclosed.
Please address the Division’s comments and submit a revised Memorandum at your earliest convenience. If you have any questions, please call Jeff Vandel at [phone].
Sincerely,
Scott T. Anderson, Director
Division of Waste Management and Radiation Control
STA/JV/km
Enclosure: Comments on Proposal for Exposure Units and Monitoring Wells
c: Lloyd Berentzen, MBA, Health Officer, Bear River Health Department Grant Koford, EHS, Environmental Health Director, Bear River Health Department Paul Hancock, ATK Launch Systems Amy Hensley, USEPA Region 8

Division of Waste Management and Radiation Control Comments ATK – Promontory Proposal for Exposure Units and Monitoring Wells to be used in the Groundwater Risk Assessments General Comment:
ATK has previously agreed to evaluate each exposure unit for both a “maximum risk” based on the
highest concentrations of COPCs detected and the risk associated with a 95% UCL for the wells identified. If this will not be done for any of the plumes (or exposure units) besides the springs, please provide an explanation to support the decision not to do this.
Plume #1:
As discussed previously, and noted in the Geosyntec Memorandum dated August 9, 2017, the hexavalent chromium plume that has been detected in the M-508 area should be evaluated quantitatively in the risk assessments. Please revise the document to address how this will be done.
Plume #4: RDX is included on the list of Groundwater Protection Standard Constituents in the Post-Closure Permit and has been detected in this plume at concentrations exceeding the EPA tap water screening level.
Please revise the memorandum to address how RDX will be evaluated in the risk assessments.