DSHW-2018-005642 - 0901a0688085186b

DSHW-2018-005642 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
July 5, 2018
Gary McEntee
Ninigret Technology East 1700 South 4650 West Salt Lake City, Utah 84104-5310
RE: Site-Wide Groundwater Monitoring Plan
Ninigret Technology Park Former Engelhard Facility UTD009073800
Dear Mr. McEntee:
In a letter dated February 26, 2018, Ninigret was instructed to perform the 8th groundwater monitoring event at the referenced facility. I am aware that my staff has discussed this issue with you on the phone. Please notify the Division when the sampling will be conducted so that my staff may schedule time to
oversight the effort.
Ninigret’s Site-Wide Groundwater Monitoring Report (Documenting the 7th Monitoring Event) that was submitted in August of 2017 included a petition to terminate groundwater monitoring at the Ninigret Technology Park. As mentioned above, the Division required monitoring to continue. However, on
completion of the 8th monitoring event, the Division recommends Ninigret evaluate the accumulated
ground data through statistical means to provide a basis for possible termination of sampling. The Division also recommends that Ninigret consult the Statistical Analysis of Groundwater Monitoring Data at RCRA Facilities, Unified Guidance, March 2009. Chapter 21.3 of the guidance appears to be
applicable for constituents at select groundwater monitoring wells at the site. In essence, the 95% UCL
should be constructed above the Theil-Sen trend lines for constituents in problematic wells and checked if and when the 95% UCL will intersect the groundwater protection standard.
(Over)

Please call Rolf Johnsson at [phone] to provide notification of the 8th sampling event. If you have questions related to the statistical evaluation, please call Helge Gabert at [phone].

Sincerely,
Scott T. Anderson, Director
Division of Waste Management and Radiation Control STA/RTJ/km
c: Gary Edwards, MS, Health Officer, Salt Lake County Health Dept.
Royal DeLegge, MPA, EHS, Environmental Health Director, Salt Lake County Health Dept. Amy Hensley, USEPA, Region 8