DEQ-CFW_00013607

From: Risen, Amy ][/D=[XCHANG[LAB5/OU=EXCHANGEADMINISTRATIVE GROUP
(FYD|BOHF2]SPDLT)/CN=REOP|ENTS/CN=F72O96857[E847COAI3F73D2O6EDFE8GfURISEN]
Sent: 7/7/20I7I0:I6:55PW1
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[e-mail];Henry.ta|[e-mail];[e-mail];[e-mail];
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CC: Tina Forrester [txf Aycdc.gov];Susan yWoore[sym8Aycdc.gov]; Selene Chou [[e-mail]];Trent LeCou|tne
[t||[e-mail]];Rachel Worley [[e-mail]]
Subject: RE: SenXRisk Assessment Knowledge Gaps
Thank you to everyone for providing feedback on our risk assessment for GenX. I'm providing a summary below, which
includes points ofcontact to follow up with. Questions 1'4vvere posed by DHHS before the call as main talking points.
Text in blue is a summary of the comments. NC DHHS makes every attempt to follow the approach used by the EPA
when doing risk assessments. Therefore, we have underlined blue text as take home messages that DHHS will be
applying to the GenX risk assessment for NC residents using drinking water originally referenced in Sun et al 2016.
DHHS intends to respond to the public with a new drinking water level and health guidance early in the week of July 101h
We are hopeful that you will be able to provide feedback on cancer and fish consumption ASAP; please see number 5
below for details. | am also interested in data we discussed on interspecies kinetics differences.
Thanks again!
Amy
subchronic to chronic extrapolation
a, We have consensus that the POD of 0.1 m k /da will also be used b the EPA Risk Assessment
Division (R&Pjjp�jsk assessment of GenX.
b, Joyce Donohue, Tracy Behoing & Amy Benson reguestedthat toxicological effects and
endpmiot
descriptions, be strengthened so we can be more specificabout the effects, associatedwith N0AELs and
PODs thatare referenced during the risk assessment,
c. It was noted that PODs on the E[HAdossier are selected and reported bychernicai manufacturer rather
than the ECH&
Z) Routes of exposure and the relative source contribution (RSQPeople may beexposed toGenXthrough routes
other than drinking water. The typical value used for RSC in risk assessment of organic chemicals is 0.2, and this
OEQ-CFVV_00013607

is the value used by the EPA for their evaluation of PFOA and PFOS drinking water health advisories. We.regpgst
uidance frc�ma the EPA and ATSDR ran the use of an RSC of 0. .
a. EPA PAD has not evaluated RSC for drinking water exposures to GenX because drinking water was not
previously thought to be a route of exposure, to this chemical.
b� EPA RAD did use 20% RSC for PFOA and PFOS dire to € biquitous presence, in the envimnment and
uncertainty about arnounts of these chemicals reaching people through the different: exposure routes.
c. EPA RAD uses 100% PSG. when looking at exposures to the infant age group.
d. DHHS intends to use 20% RSC rased on the EPA decision tree for derivin water uafit-
82 criteria EPAm
rrrr.►.Pchildren igtt< s_i _g��as � ���tors from the
.............. .._..........................................
new EPA RAGS supplement tOSWER Directive 0 00,1-120 ,
3) Risk assessment method and interspecies uncertainty factor: The default value for interspecies variability of 10
is likely to underestimate the toxicity of GenX to humans. We present the EPA method used to extrapolate a
human equivalent dose (HED) for PFOA and PFOS in this document. Interspecies uncertainty modeling for PFOA
and PFOS yielded a calculated factor of 140 to 710X for kinetics differences and an additional 3X was allocated
for other variability across species. The total uncertainty accounted for across species by EPA for PFOA and PFOS
was calculated by DHHS and the maximum was 2,100X. We also re nest uidance from the EPA and ATSDR on
area ro riate inters ecles ur certairrt factor for X.
a. DHHS understands that EPA RAD curr~ent►v intends to use a i..IP,—,,®100 for their risk assessment for
the consent order for GenX manufacturir� g.
b. EPA: While. human PFOS & PFCA clearance rates sire slower in hu€nans than test: animals,, interspecies
kinetics variability is not expected to occur- at the same magnitude for GenX. 'Me supporting information
comes from a conipwison of the clearance rates for branched vs linear PFOAs, in which branched
isorners Fire cleared faster., GenX is branched and so would be predicted to clear faster.
i. DHHS repuests references on comparison of branched vs linear PEDAs, renal transfer proteins
used, and any additional information helpful in reviewing the prediction of the interspecies
variability expected for GenX. Follow Grp discussions will go through Joyce Donohue, Catherine
Aubre,e, and Jaime Strong as points of contact.
c, Additional UFs were discussed, including the subchronic to chronic extrapolation. EPA. PAD does € c.,A use
a UF�ubdhh m,-UI;Onir as Part of its typical Procedure. DHHS explained our goal to he protective of Public
health over a I`€fetirne of exposure, EPA explained that EPA IRIS procedure does focus more on lifetime
p€ sr�res and their_ r�isl� assessment: does ad€d iu a OF sr�, �.,3� cr, �F, �..of 1 .
.....................................................................................
d. Questions were raised regarding EPA`s curre.nt: review of the GenX consent order and associated risk
assessment, now that a release to a water source is known, will the risk assessment include a public
drinking,;d water level?
4) Drinking water concentration guidance for other PFECAs: The Sun et al 2016 publication identified not only
GenX, but also other perfluoroalkyl ether carboxylic acids (PFECAs) present in the Cape Fear River and local
drinking water in 2013 and 2014. Quantification of the concentrations of other PFECAs was not possible due to
the lack of analytical chemistry standards, however some PFECAs may have been present at concentrations 15
times higher than GenX. Presumed high concentrations are prompting questions about drinking water safety,
however no toxicity data is available for these PFECAs. We re nest uidarrce frorn the EPA arrd ATSDR err a
health rotect►ve drir kir� water valve that carr be rov►ded to residents of this communit . Would it be
P.pEppriate._to use. t e_PFOA + FOS heath advisor y pf 7t) ng� L?
a. Mania Doa and Catherine Aubree will review the PFECAs chernical structures to see if general advice can
he given on how much we can read across health concerns from PFOA and PEGS. It is not within the
scope of their work on GenX to review PEf CAs at this time and it is understood that guidance along
DEQ-CFW 00013608

those linos may be limited. Amy Risenwill provide the sugglernental document for Sun et @I to clarify
the PFECAs in questis�n.
53 Additional questions raised in call
a. Fish Consum tiorr:
i. S: The public is asking about safety offish consumption. n. Can ter:. EPA make any
recomrnendations?
ii, EPA: 1'he EPA does not expect GenX to bioaccurnulate,There is some data on concentrations in
fish from docurnents that are confidential, as well as so€ne non -confidential data.
1. The DHHS spore with Tale Henry after the Gall for clarification. She explained that the
BCF re.porte.d by Hoke. et al 2016 is low enough a—, to € of typically warrant fish
consumptions studios, EPA will follow up Monday with a statement with the appropriate
caveats for the unknowns of ernerging chemicals and limited data,
h. Cancer Risk Assessment:
i. S: The public is concerned about: the risk of cancer frorn GenX, We. have limited data, but
can the. EPA suggest a way to convey the risk of cancer?
ii, EPA: Joyce Donohue will review the raw data from OECD453 to determine if the notes on the
rate of occurrence for liver necrosis are sufficient to calculate a risk. Arny Risen will provide the
ra data, which had been provided by Chernours. Arny also has rave € ata for OECD 407 GenX
testing for rats & mice, if needed by anyone in the group.
From: Risen, Amy J
Sent: Wednesday, July 05, 2017 7:38 PM
To: 'Audra Henry' <[e-mail]>; 'John Wheeler' <[e-mail]>; '[e-mail]'
<mitch ell. ken @epa.gov>; '[e-mail]' <[e-mail]>; '[e-mail]'
<[e-mail]>; '[e-mail]' <[e-mail]>; '[e-mail]'
<[e-mail]>; '[e-mail]' <[e-mail]>; '[e-mail]'
<[e-mail]>; '[e-mail]' <[e-mail]>; '[e-mail]'
<[e-mail]>; 'Doa, Maria' <Doa.Maria @epa.gov>; Mort, Sandra L <[e-mail]>; Shehee,
Mina <[e-mail]>; Dittman, Elizabeth <Beth.Dittman @dhhs.nc.gov>; Holt, Kennedy
<[e-mail]>; Langley, Rick <[e-mail]>; Brower, Connie <[e-mail]>
Cc: 'Tina Forrester' <[e-mail]>; 'Susan Moore' <[e-mail]>; 'Selene Chou' <[e-mail]>; 'Trent LeCoultre'
<[e-mail]>; 'Rachel Worley' <[e-mail]>
Subject: GenX Risk Assessment Knowledge Gaps
Hello everyone!
NC DHHS has been discussing GenX with both EPA and ATSDR and we really appreciate the help you've been giving us.
We'll be holding a conference call tomorrow to talk about the progress we've made on our GenX risk assessment, and
talk about knowledge gaps. We'll be asking for rapid feedback within the next week to help inform our risk
communications with the public.
I've attached a document for you to review with requests for feedback bolded in purple.
Thanks so much and talk to you all tomorrow!
DEQ-CFW 00013609

kivision Public Health, Occupational and Environmental Epidemiology
North Carolina Department of Health and Human Services M
[phone] office
[phone] fax
Amv,Rissn(dI,dhhs,no.00v
OEQ-CFVV_00013610