DEQ-CFW_00010136

From: Barrows, Robin [/O=NCMAIL/OU=EXCHANGE ADMINISTRATIVE GROUP
(FYDIBOHF23SPDLT)/CN=RECIPIENTS/CN=ROBIN. BARROWS]
Sent: 8/27/2012 6:30:45 PM
To: Moore, Sandra [/o=NCMAIL/ou=Exchange Administrative Group
(FYDIBOHF23SPDLT)/cn=Recipients/cn=sandra.moore]
Subject: RE: NCSAB Final Recommendation on PFOA
Sandra,
I am so happy that the information I sent was useful. Please let me know if there is anything you need.
Regards,
Robin
Robin R. Barrows, MS
Environmental Senior Specialist
CSC DEN R Division of Air Cluality
1641 "fail Service Center
Raleigh, I''dC 2 7699-1641
Phone/FAX: [phone]
h__t__tR.�. n_ca i r. org
[e-mail]
Email correspondence to and from this address is subject to the North Carolina Public Records Law and may be disclosed to third
parties unless the content is exempt by statute or other regulation.
Please cons<der Me enviroYt,Y ent - do you remlly need to 1pr r;?t t"hrs docurnen!',
Moore, Sandra
Sent: Monday, August 27, 2012 2:08 PM
To: Barrows, Robin
Cc: Moore, Sandra; Brower, Connie
Subject: RE: NCSAB Final Recommendation on PFJ
Robin,
Thank you so much! I printed the minutes and didn't even think to review them for this Information. My
apologies. This is exactly what I needed.
Sandra
i
State Water Quality Standards Co -coordinator
Divisi0n of Water Quality
NC Department of Environment and Natural Resources
1617 Moil Service Center, Raleigh, NC 27699-1617
Sandra. [e-mail]
[phone]
Note E-mail correspondence to and frorn this address n7ay be subject to the North Carolina Public Records Loan and may be disclosed
to third parties.
From:• Robin
Monday, August i +;
Moore,
Subject: RE: NCSAB Final Recommendation on PFJ"
DEQ-CFW 00010136

| apologize for the confusion. | have attached the reference paper (Andersen U6... ) for your records. While hdescribes
the P13PK model that was developed to determine resorption of PFOA in monkeys it does not state the 0.12 ug
in8ested/ko/uo/mLfactor outright. | have included some meeting minutes where PFOAwas discussed asfurther
explanation ofthis factor.
| have also attached a presentation that Dr. OexveU made tothe 5AB (OexveU 2007) in which hedescribes the PBPK
model further, and the associated minutes (121")xvherehecondudes
(l) this P13PK model can be used to model PFOA in humans and can be used to estimate exposures associated
with measured serum levels;
(2) environmental exposures ofPFOA(no/ko/day)can be roughly estimated as 0.12 x plasma concentration (in
ng/mL). Current "background" PFOA plasma concentrations of —5 ng/mL imply an exposure of —0.6
no/kg/day
(3) an RfD of 90 ng/kg/day is suggested based on serum PFOA benchmark concentrations in animal studies
having a total uncertainty factor of3O
(4) there is no evidence of greater sensitivity in early life (sensitive individuals may be those with chronic renal
impairment orpossibly enOAT po|ymorphiom).
In an excerpt from the 147 1h minutes I found further explanation from Dr. Clewell:
Dr. Oewelldescribed that the model was developed usingmonkey data and then adjusted tohuman. Totest the model,
holf-lifedata from Olsen et. ot(2DU3)occupational exposures were used. Arelationship between exposure and plasma
levels similar to those seen /n the Little Hawking study was predicted by the model. He also noted that o similar result
could be obtained if one empirically estimated a relationship between plasma and intakefrom the Little Hawking data.
Dr. Starr asked /fthat the conversion factor todetermine environmental exposures ofPFOA /n W/sD.22xp/os/no
concentration (in ng/hrUand Dr. (Jewe8confirmed.
| have also included recent meeting minutes (1641h ) where Dr. Starr gave further clarification regarding the U.12u8
ingested/kg/ug/mL factor to Dr. Dorman:
Dr. Dorman reiterated his needforclarification regarding the use of Dr.Oewell's PBPK model. Dr. Starr
responded that the model was used to scale PFOA water concentrations to PFOA blood serum concentrations at
low doses, and that no other aspects of the model were utilized. Clewell's model was not usedfor to determine a
POD.
Please let me know if you need more information or explanation. I am more than happy to provide any assistance I can.
Robin RLBarrows, h8S
Environmental Senior Specialist
N[DEN RDivision mfAir Quality
-164-1 Mail Service Center
Raleigh, NC 27699-/64/
Phone/FAX:(919)7u7-Q445
Emiil correspondence to and frorn this address is subjectto the North Carolina Public Records Law and may be disclosed to third
parties unless the content is exernpt by statute or other regulation.
Ps'pase, conshler the environment dnYou oos,�Yneed to print this d'.9mmmO
OEQ-CFVV_00010137

From:Moore, Sandra
Monday, August1 9:37 AM
Barrows, Robin
Moore, •ra; Brower, Connie
. is Final Recommendation on ]
Hi Robin,
Connie and I are in the process of reviewing the SAB's PFOA risk assessment and recommendation. We are struggling to
understand the derivation of the 0.12 ug ingested/'kg/ug/rnL factor used to derive the exposure level or) page 17 of the
risk assessment. The reference for this ingested factor is Clewell et: al., 700B. This reference that appears on page 76 is
an abstract. I have searched the internet for a related article to no avail. Is there another reference or paper that
explains how this factor was derived that you could provide? We anticipate questions regarding the use of this factor
and we want to be able to explain where it came from and how it was derived.
Thanks for any information that: you are able to provide.
My best regards,
Sandra
State Water Quality Standards Co -coordinator
Division of Water Quality
C Department of Environment and Natural Resources
1617 Moil Service Center, Raleigh, O 7S -1617
.: :. . 807-6417
Note: E-mail correspondence to and from this address rnoy be subject to the North Corolina Public Records Lain and may be disclosed
to third parties.
From: Barrows, Robin
Sent: Thursday, August 09, 2012 11:21 AM
To: Wakild, Chuck
Cc: Moore, Sandra; Brower, Connie; NCDENR.DENR.DAQ.SAB_committee; Cherry, Lori; Daniel, Lee; Holman, Sheila
Subject: NCSAB Final Recommendation on PFOA
M
The NCSAB has completed its assessment of PFOA and has provided a recommendation (attached). I have placed the
original transmittal letter, signed by Director Holman, and the final risk assessment in inner office mail to you today. The
transmittal letter is dated tomorrow. Please let me know when you receive this document.
Should you, Ms. Moore, Ms. Brower, or any other staff have any questions regarding the assessment please do not
hesitate to contact me directly.
r � �
Robin R. Barrows, MS
Environmental Senior Specialist
NC DEN R Division of Air quality
1641 Mail Service Center
Raleigh, IBC 27699--1641
Phone/FAX: [phone]
DEQ-CFW 00010138

http:llwww.ncair.org
[e-mail]
Erniil correspondence to and from this iddress is subject to the North Carolina Public Records Law and riiy be disclosed to third
parties unless the content is exempt by statute or other regulation.
Please Consider the environme,,�t - do you rpoll,vr?eed try Print this dowment.'-'
DEQ-CFW-00010139