DEQ-CFW_00004159

From: Moore, Sandra [SANDRA.MOORE]
Sent: 11/3/2010 3:04:21 PM
To: david brewster [[e-mail]]
CC: Moore, Sandra [/o=NCMAIL/ou=Exchange Administrative Group
(FYDIBOHF23SPDLT)/cn=Recipients/cn=sandra.moore]; Brower, Connie [/o=NCMAIL/ou=Exchange Administrative
Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=connie.brower]; Reid, Dianne [/o=NCMAIL/ou=Exchange
Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=dianne.reid]
Subject: p-isopropyltoluene IMAC Request comments
Attachments: DWQ GWStandards SOP.pdf; IMACBasisCB.pdf
s
As requested in your September 23, 2010 email, I have reviewed your draft IMAC request for p-
isopropyltoluene. As reflected in my comments below, without additional information, the DWQ will not be
able to establish an IMAC for p-isopropyltoluene.
1) The IMAC request should include a calculated IMAC along with supporting documentation
(calculations, references and methods) generated in accordance with the requirements of 15A NCAC 2L
.0202 (d) & (e). Please visit our groundwater web site at the following address to link to a copy of the
2L .0202 regulations littp://portal.ncdetir.or web/wq/ps/esu/ wstandards (under Frequently Requested
Documents).
Attached you will find an example of the development of an IMAC for PFOA (C8) that can be used as a
guide. I have attached a copy of the DWQ's SOP for establishing a groundwater standard or IMAC as
well.
2) Your request included an LD50 for p-isopropyltoluene at 4, 750 mg/kg (RAT), taken from the Merck
Index. The LD50 may be used to compare p-isopropyltoluene's toxicity to other substituted benzene
compounds; however, a reference dose is needed to establish an IMAC. I was unable to find a reference
dose for p-isopropyltoluene in the literature or common toxicity databases, such as EPA's Integrated
Risk Information System (IRIS). I contacted the Superfund Health Risk Technical Support Center in
hopes that they would be able to provide a reference dose to use to develop an IMAC; however, they
were not able to provide a reference dose.
3) Your request included "Occ = finished drinking water max concentration of 11.8 ug/1" provided by
Thomas Carpenter, EPA Region 4. Information to support this concentration as a potential IMAC must
be submitted. Please provide the reference dose that was used, as well as its derivation, and the
exposure assumptions used. Again, all calculations, references and methods used to derive the 11.8 ug/l
concentration must be submitted in support of the IMAC.
DEQ-CFW 00004159

Note: I was unable to access the RTECs database that was used by EPA to obtain the toxicity
information used to support the 11.8 ug/l finished drinking water max concentration. It appears you
have to pay to subscribe to the database.
4) Your request stated that Maine has a drinking water standard for p-i sopropyl toluene of 70 ug/l. I also
saw that New Hampshire has one at 260 ug/L (http://toxnet.nlni.nih.gov/cgi-bin/sis/searcii). Both were
taken from a state survey in 1993. 1 suggest contacting these states and ask if they will provide the
information used to developed these standards —for example, what studies were used to derive reference
dose and what exposure assumptions were used in the calculation.
I hope these comments are helpful. Please don't hesitate to contact me if you have questions or would like to
discuss further.
Best regards,
Sandra
State Water Quality Standards Co -coordinator
Division of Water Quality
NC Department of Environment and Natural Resources
1617 Mail Service Center, Raleigh, NC 27699-1617
Note: E-inoil correspondence to and from this address may be subject to the North Carolina Public Records Low and inoy be disclosed
to third parties.
DEQ-CFW-00004160