DEQ-CFW_00010148

1. Change "DEK4"to"D\NQorsuccessor" inD1O2(6)&(7).
2. Add definition for maximum contaminant level (MCL) and national secondary drinking water
3. Update pH units to pH standard: pH units or unitless.
4. Update to standards in .0202 (g) as necessary to incorporate most up-to-date reference doses,
cancer potency factors, etc
S. Incorporated current Interim Maximum Allowable Standards.
6. DimxinTECF—|MA[s:
Dibenzofunan: Don't Update from 2Ouo/Lto7oo/Lbased onEPA PPRTVscreening level —had a
1O,000UF--|ovvconfidence. Leaveasinterim?
PFOA:Update from Zuo/Lto1uo/Lbased onN[SA8recommendation. Studies/RfDbut leave
as interim.
Take 56|MACsaspermanent standards? Note basis for current 5O|MACuis33N[s/14Cs/ Z
K4Cb/4taste/ Sodor
Electronic files for the 2010-12 GWTR can be found on the S drive at
Hard copies ofsummary tables and worksheets can befound inthe white notebook labeled ZU1U-1Z
How many standards or IMACs increased/decreased? How many above PQL or below PQL?
Acrylarnide: Update current 2L from 0.008 ppb to 0.07 ppb based on updated CPF from 3/22/10 IRIS
Toxicological Review.
n-Butyl benzene: Current standard of7Uuu/Lbbased onthe use ofthe RfDfor ethybenzeneasa
surrogate recommended byEPA years ago. EPA nolonger supports this recommendation. EPA has
established aPPRTVchronic p'RfDofO.O5mu/ko/day. Change standard to3SOuo/L
using PPRTV RfD rather than using ethy|benzene as a surrogate.
OEQ-CFVV_00010148

Side note: Nqupdate for sec- orbert- butyl benzene Leave them as is based on past
recommendation from EPA to use ethy|benzene as a surrogate. Recommended removing these
standards during last GVVTRbut EIVI[denied request.
Butyl Benzyl Phthalate: Update current standard of1,UUOuu/Lwhich isbased onthe |R|5 MID, toJO
u8/Lbased onthe EPA PPRTVderived provisiona|-CPF.
Chloroethane (ethyl chloride): Current standard of 3000 ug/L is based on a RfD of 0.4mg/kg/d from the
RA|8site and the October 2OD4EPA PRGsTable. This RfDhas since been withdrawn. DVVQ staff
requested removal of this standard during last triennial review but EIVIC denied request. EPA Regional
Screening Levels Tables have replaced the Region 9 Tables. The EPA Regional Tables do not list an RfD,
nor does IRIS or any other of the toxicity data references we use. Currently, the 2007 PPRTV lists a
subchronicRfDofO.l. Should xveleave the standard alone ormodify the RfDbyafactor of1Oto
account for subchronic to chronic exposure? |fso, the revised ZLwould be7Ouo/L Recommendation:
Change standard to70ugyLusing PPRTVRfDadjusted for chronic exposure.
Chloromethane (methyl chloride): Current standard based onaHEASToral cancer potency factor
extrapolated from a mouse inhalation study. However, EPA IRIS states that the most appropriate cancer
designation isasa Group D—Notdassifiab|easto its human carcinogenicity. Under newest cancer
guidelines it is classified as "carcinogenic potential cannot be determined."
Originally recommended changing the standard from 3 ug/L to 30 ug/L based on noncancer health
effects, using the JOO9EPA Health Advisory RfDofO.0U4m8/k8/day. However, Z0lJHealth Advisory
has withdrawn this RfD. Current recommendation is to just leave it at 3 uglL.
Chromium (Total), Hexavalent Chromium and Trivalent Chromium: Recommend removing current
groundwater standard for total chromium and replacing it with atrivalent chromium Cr(III) standard of
5000 ug/L and a Hexavalent chromium Cr(VI) standard of 10 ug/L based on current IRIS RfDs. If
Responsible Party does not want to analyze for both, then default is total of 10 ug/L. Thehexava|ent
PQL of approximately 50 ug/L is still a limiting factor to having an effective hexavalent chromium
standard. Having the two standards may provide some relief with cleanup levels where hexavalent
chromium is not an issue.
FYI, Option 2: / do not recommend this option. There is no CPF currently published in IRIS;
however, the Sept 2010 Draft Toxicological Review developed an oral CPF of 0.5 mg/kg-day
(note that /n9/JCO2EPA archived this tax npview). New Jersey developed anoral CPFofU.5
mg/kg/day also and the EPA Regional Screening Levels cite the NJ CPF and use it to establish
their tap water screening level. Using this CPF, the 2L for hexavalent would be 0.07 ug/L.
Cyanide, free: Update current 2L of 70 ug/L to 2 ug/L based on updated EPA IRIS RfD.
Update standard from 7Ouu/L1Ouu/Lbased on updated IRIS reference dose
OEQ-CFVV_00010149

1,4-Dioxane: Update 2L standard from 3 ug/I to 0.4 ug/L based on updated IRIS cancer potency factor
(8/2010).
Dioxin (2,3,7,8-TCDD): Propose changing to Dioxin (2,3,7,8-TCDD) and total dioxin -like compounds and
using USEPA's Toxicity Equivalence Factor methodology to determine compliance. Some chemicals are
members of the same family and exhibit similar toxicological properties; however, they differ in the
degree of toxicity. A toxicity equivalence factor (TEF) may be applied to adjust the measured
concentrations to a toxicity equivalent concentration. EPA and the WHO provide various dioxin -like
toxicity equivalency factors for dioxins, furans and PCBs. This change was requested by the DWM.
Currently, when there is not a 2L standard, the standard becomes the PQL so this approach will help in
evaluating sites with dioxin contamination and is consistent with EPA.
Ethylbenzene: Current 2L standard of 600 ug/L is based on an odor threshold. The proposed standard of
3 ug/L is based on the use of the Cal -EPA CPF as recommended by USEPA. Since this is a common UST
petroleum site contaminant the DWQ may get some resistance from the American Petroleum Institute
and DWM UST Section. The EPA Regional Tables use the Cal -EPA CPF and SL is 6.1 ug/L for ingestion.
Cancer classification is USEPA Class D; IARC class is 2B. IARC class based on NTP inhalation studies. Cal -
EPA derived the oral cancer potency from the inhalation cancer potency. Ethylbenzene is listed on the
IRIS track but no dates are given. Leaning toward leaving current standard in place due to lack of
"oral" studies.
If 2L rules are changed to allow the EMC to develop groundwater standards less
stringent than the MCL, then this standard would need to be updated based on the most recent USEPA
IRIS health effects data (11/18/11). The current standard of 5 ug/L is the MCL and the proposed
standard is 20 ug/L based on an updated IRIS CPF.
If 2L rules are changed to allow the EMC to develop groundwater standards less
stringent than the MCL, then the current 2L standard of 0.7 ug/L would need to be updated to 20 ug/L
based on the most recent USEPA IRIS health effects data (2/12).
1,2,4-Trichlorobenzene: Current standard of 70 ug/L, based on IRIS RfD, can be updated to 1 ug/L base4
on use of EPA'sderived PPRTV CPF.
TrichloroethViene:•. • •' based on '+ 2009 Health Advisory forb
updated to 0.8 ug/L based on EPA IRIS CPF published 9/2011.
cancer potency factor.
V am
DEQ-CFW 00010150

n-PropVI benzene: I he current stancIard_ot_/U­u­­g7U­i_s based on the _RtD_t­o­r­e_fh_VThenzene with aF
uncertaintV factor of 10 applied. EPA published a PPRTV screening RfD based on the use of
ethVIbenzene as a surrogate without the UF. Recommendation: leave standard as is.
Simazine: H EAST CPF available (0.12mg/kg/daV) but recommended leaving standard at 4 ug/L which
• PFOA (awaiting SAB and EPA updated toxicitV assessment —EPA maV finalize health advisorV
later this Vear. SAB tabled for 6 months pending new data)
• Dibenzofuran (awaiting pending EPA final assessment)
OEQ-CFVV_00010151