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Noah Carolina Department 6f Health and Human Services
Division of Public Health • Epidemiology Section
1912 Mail Service Centex - Raleigh, Noah Carolina 27699-1912
Tel [phone] - Firr919-733-9555
Mchsel F nasley, Governor
December 6, 2004
Mr. Kevin Martin, Hearing Officer
Environmental Management Commission Groundwater Committee
Soil and Environmental Consultants, PA
11010 Raven Ridge Road
Raleigh, NC 27614
Mr_ Larry Jordan, Chairman
Environmental Management Commission Groundwater Committee
P.O. Box 220
Apex, North Carolina 27502
Mr. Andrew Pitner, Bearing Officer
DENI2/DWQ/Aquifer Protection Section
Mooresville Regional Office
610 East Center Avenue
Suite 301
Mooresville, NC 28115
Mr. David Hance
1617 Mail Service Center
512 N. Salisbury Street
Raleigh, NC 27604
Dear Mr_ Martin, Mr. Jordan, Mr. Pitner and Mr. Rance:
Carmen HookcrOdmn,Sccrcmq
We are writing to point out areas in the existing 15A NCAC 2L.0202 rule that
enables the Commission to consider scientifically valid toxicological data in addition to
the 6 criteria in .0202(d). It is the position of the Division of Public Health that based on
the language in .0202(e), it may be unnecessary to revise the criteria in .0202(d) or (e) as
is currently being considered -
The existing 15A NCAC 2L.0202 rules allow for consideration of new scientific
health information in addition to the 6 criteria in _0202(d) for establishing standards.
Language in .0202(e) gives the Commission authority to consider additional health risk
assessment information when establishing standards. We call your attention to the
recommendations from the Division of Public Health for two standards, 1,1-
dichloroethylene and 1,4-dioxane fox which language in .0202(e) was used.
® Location: 2728 Capkd Boulevard • Parker Lincoln Building Raleigh. N.C. 27604 A. Equal Oppnnanity Fmploycr
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To calculate the recently recommended level of 0.35 mg/L for 1,1-
dichloroethylene, the Division of Public Health used language contained in _0202(e)(1),
which allows the Commission to use US EPA's Integrated Risk Management System
(IRIS) to establish concentrations of substances for the criteria in .0202(d)(1) through (6).
For 1,1-dichloroethylene the Division of Public Health initially recommended a level of
0.007 mg/L, which was based on the lowest value of the 6 criteria in .0202(d) (EPA
Maximum contaminant level or MCI, in this case). During the public comment period,
Helms Mulliss Wicker law firm submitted information that the chronic oral reference
dose used to establish the current Maximum Contaminant Level is outdated_ This
reference dose was originally on US EPA's Tntegrated Risk Information System (IRIS)
database, but it has been replaced with a more up-to-date reference dose. Since .0202 (e)
clearly states that IRIS is the preferred reference for obtaining toxicological data, the
Division of Public Health subsequently recommended to revise the groundwater quality
standard to 0.35 mg/L. This recommendation will enable the Commission to take the
updated reference dose into consideration_ In other words, the more up-to-date
toxicological information in EPA's IRIS .0202(e)(1) made it necessary to discount the
validity of the MCL .0202(d)(5).
Similarly, the Division of Public Health used .0202(e)(4), which allows the
Commission to use other appropriate, published health risk assessment data and
scientifically valid peer -reviewed published toxicological data to establish concentrations
of substances for the criteria in .0202(d)(1) through (6). For 1,4-dioxane the Division of
Public Health initially recommended a level of 0.00318 mg/L based on the carcinogenic
slope factor published on EPA's IRIS in 1990. Several commenters submitted scientific
information that the published carcinogenic slope factor is based on an invalid
assumption. US EPA is currently reviewing the published carcinogenic slope factor in
light of this new information. In response, the Division of Public Health recommended to
maintain the current standard of 0.007 mg/L until U.S. EPA completes its review. The
Division of Public health would review the standard for 1,4-dioxane in 2006, once the
EPA review is completed and published on IRIS.
We have presented this information to the Division of Public Health's
representative of the Attorney General's (AG) Office. He has raised several questions
but needs more time to review this issue in detail with other attorneys in the Attorney
General's Office, Department of Environment and Natural Resources (DENR),
Groundwater staff, Public Health staff and Commission. As a result of this, we request
that the Environmental Management Commission (EMC) Groundwater Committee
postpone consideration of the 33 groundwater quality standards and any subsequent
request to have staff rewrite the criteria for establishing groundwater quality standards
until the February 2005 meeting. This will allow time for a meeting between the
Division of Public Health's representative of the AG's Office and the FMC's AG's
representative, DENR Groundwater staff, Division of Public Health staff, and EMC
Groundwater Committee members.
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Page 2
December 6, 2004 Letter
We would like the opportunity to speak with you about this matter. You can
reach us at 919-73 3 -34 10.
Sincerely,
6�/jt, �
Dr. Luanne K. Williams, Toxicologist
Medical Evaluation Risk Assessment Unit
Occupational and Environmental Epidemiology Branch
NC Division of Public Health
North Carolina Department of Health and Human Services
i ,
Mr. William 7. ate, PE, CIH, Supervisor
Medical Evaluation Risk Assessment Unit
Occupatioual and Environmental Epidemiology Branch
NC Division of public Health
N7��tHealth and Human Services
Dr. Kenneth Rudo, Toxicologist
Medical Evaluation Risk Assessment Unit
Occupational and Environmental Epidemiology Branch
NC Division of Public Health
North Carolina Department of Health and Human Services
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