NC0087629_Monitoring (Information)_20190826

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Governor
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MICHAEL S.REGAN s n.nm /..
Secretary ---
LINDA CULPEPPER NORTH CAROLINA
Director Environmental Quality
August 26,2019
Jason Prosser,PG
NCDOT-Asphalt Testing Site No. 6-48
Roadside Environmental Unit, 1558 Mail Service Center
Raleigh,NC 27699
Subject:NC0087629
Asphalt Testing Site#6
Investigative Monitoring
Dear Mr.Prosser,
Several emerging compounds have been found in North Carolina waters,including the chemical 1,4-
dioxane. Data reviewed as part of the Third Unregulated Contaminant Monitoring Rule(UCMR3)has
indicated elevated concentrations for 1,4-dioxane in the Cape Fear River Basin. In addition, ambient
monitoring performed by DWR's Water Sciences Section have confirmed the presence of the chemical in
the Cape Fear River Basin. See ambient monitoring study reports listed under the following link:
https://deq.nc.gov/about/divisions/water-resources/waterresources-data/water-sciences-home-page/1-4-
dioxane
Background
1,4-dioxane is a clear liquid that is highly miscible in water. It has historically been used as a solvent
stabilizer and is currently used for a wide variety of industrial and manufacturing purposes. The
compound can be found in industrial solvents,paint strippers, and varnishes and is often produced as a
by-product of chemical processes to manufacture soaps,plastics, and other consumer products.
The U.S.EPA has not established a maximum contaminant level for 1,4-dioxane in drinking water but
has characterized it as"likely to be carcinogenic to humans"and has established a drinking water health
advisory of 35 pig/L. North Carolina has a calculated human health surface water criterion with an
associated estimated lifetime cancer risk of one in one million at a concentration for 1,4-dioxane of 0.35
µg/L in water supplies and 80 µg/L in all other waterbodies(15A NCAC 02B .0208).
Required Actions
To assess the levels of these compounds throughout the Cape Fear and to assist DWR in developing a
Management Strategy to address and reduce levels of these emerging compounds,Industries permitted
under the National Pollution Discharge Elimination System(NPDES)which employ processes associated
with the discharge of these compounds are hereby required to perform investigative monitoring at the
treatment plant effluent for 1,4-dioxane once per month for three consecutive months starting in October
2019. Such investigative actions can be required under l5A NCAC 02B .0508 (b)(2) and G.S. 143-
215.66.
Samples collected should be representative of the typical wastewater discharged from your facility.
Sufficiently sensitive test methods shall be used.
• To locate a lab certified to perform 1,4-dioxane analysis using EPA Method 624.1,please
visit https://deq.nc.gov/about/divisions/water-resources/water-resources-data/water-
D E �,, North Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street 11617 Mail Service Center I Raleigh,North Carolina 27699-1617
NORTH C ROUNA
wwrnment m Environmental ouwn 919.707.9000

scienceshome-page/laboratory-certification-branch/certified-laboratory-listings.Be sure to
specify 1,4-dioxane by EPA method 624.1 when contacting the labs.The Division
recommends that the lab uses sufficiently sensitive test procedures with a target Practical
Quantification Level(PQL)of approximately 1 µg/L.
• In addition to reporting the monthly results on the facility's eDMR,please send a copy of all
three monthly results to the DWR NPDES Complex Permitting Unit by January 31,2020 at
the following email address(please include the lab sheets with the test results):
[e-mail] include your NPDES permit number in your subject
heading.
If your effluent samples exceed the human health surface water criteria for 1,4-dioxane pertaining to your
receiving stream classification,DWR NPDES Complex Permitting Staff will evaluate the impact on the
receiving stream based on your facility's discharge and receiving stream volume. If necessary,NPDES
staff will contact you to develop a corrective action plan to begin reducing or eliminating 1,4-dioxane
discharges from your facility.
More Information
The Department looks forward to working closely with you on this important public health issue. Data
from the Cape Fear River Basin will be evaluated to determine next steps to reduce the discharge of 1,4-
dioxane throughout the State.
Please contact any of the following DWR NPDES Complex Permitting Unit staff members if you
have any questions or concerns: Julie Grzyb 919-707-3605, Cassidy Kurtz 919-707-3613 or Nick
Coco 919-707-3609 or via email([e-mail]).
Sincer ly,
C ___
Lin a Culpepper,Director
Division of Water Resources,NCDEQ
Cc: Dana Satterwhite,WSS
Julie Grzyb,NPDES
Rick Bolich,Raleigh Regional Office