Wednesday
January 30, 1991
Part II
Environmental
Protection Agency
40 CFR Parts 141, 142, and 143
National Primary Drinking Water
Resuistions; Final Rule
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3326
Federal Register / Vol. 56. No. 20 / Wednesday. January 30. 1991 ,/ Rules and Regulations
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Parts 141, 142, and 143
[WH-FRU-3380-1)
National Primary Drinking Water
Regulations—Synthetic Organic
Chemicals and Inorganic Chemicals;
Monitoring for Unregulated
Contaminants; National Primary
Drinking Water Regulations
Implementation; National Secondary
Drinking Water Regulations
AGENCY: U.S. Environmental Protection
Agency (EPA).
ACTION: Final rule.
SUMMARY: By this document. EPA is
promulgating maximum contaminant
level goals ,'MCLCsj and National
Primary Drinking Water R^g-a!a:ions
(N'PDVVRs) for 26 syr.t'-stic organic
chemicals (SOCs) and 7 inorganic
chemicals flOCs). (The MCLCs and
MCLa for aldicarb. aldicarb suifoxide.
aldicarb sulfone. pentachlorophenol and
b-irium are reproposed elsewhere in
today's Federal Register dus to changes
in the health basis for the MCLGs and/
or revised MCLs.) The NTDVVRs consist
of maximum contaminant levels (MCLs) .
or treatment techniques for the SOCs
and lOCs. The NPDWRs also include
monitc.-..ig. reporting, and public
notification requirements for these
compounds. This document includes the
best available technology (BAT) upon
which the MCLa are based and the BAT
for the purpose of issuing variances. The
Agency is promulgating secondary
MCLs (SMCLs) for two contaminants
and one-time monitoring requirements
for approximately 30 SOCs and [DCs
that are not regulated by N'PDWRs.
EFFECTIVE DATE.1 All sections (141.11,
141.23. 141.24. 141.32. 141.40, 141.50.
141.80. 141.61, 141.62. 141.110. 141.111.
142.14. 142.15, 142.16, 142.57. 142.62.
142.84, 143.3. and 143.4). of thii regulation
are effective July 30.1992. The
information collection requirements of
5§ 141.23. 141.24 and 141.40 are effective
Juiy 30. 1992 if the Information
Collection Request is cleared by the
Office of Management and Budget
(OMB). If not, the requirements will be
effective when OMB clears the request
at which time a document will be
published in the Federal Register
establishing ihe effective date. In
accordance with 40 CFR 23.7. this
•regulation shall be considered final-
Agency acuor for the purposes of
judicial review at 1 p m.. Eastern time on
February 13. 1991.
ADDRESSES: A copy of the public
comments received. EPA responses, and
all other supporting documents
(including references included in this
notice) are available for review at the
U.S. Environmental Protection Agency
(EPA). Drinking Water Docket. 401 M
Street. SVV.. Washington. DC. 20460. For
access to the docket materials, call 202-
382-3027 between 9 a.m. and 3:30 p.m.
Any document referenced by an MRID
number is available by contacting Susan
Laurence. Freedom of Information
Office. Office of Pesticide Programs, at
. 703-55--4454.
Copies of health criteria, analytical
methods, and regulatory impact analysis
documents are available for a fee from
the National Technical Information
Service (NTIS). U.S. Department of -
Commerce, 5285 Port Royal Road.
Springfield. Virginia 22161. The toll-free
number is 800-336-4790. local: 703-437-
4350.
FOR FURTHER INFORMATION CONTACT: Al
Havinga. Criteria and Standards
Division. Office of Drinking Wa'er
(WH-550). U.S. Environmental
Protection Agency, 401 M Street. SW.,
Washington. DC 20460, 202-382-5555. or
one of the EPA Regional Office contacts
listed below. General information may
also be obtained from the EPA Drinking
Water Hotline. The toll-free number is
800-426-4791. local: 202-382-5533.
EPA Region*] Office*
I. JFK Federal Bldg.. room 2203. Boston, MA
02203. Phone: (617) 565-3602, Jerry Healey
0. 28 Federal Plaza, room 824. New York. NY
10273. Phone: (212) 264-1800. Walter
Andrews
HI. Ml Chestnut Street. Philadelphia. PA
19107, Phone: (215) 597-8227. Jon Capacasa
IV. 345 Courtland Street. Atlanta. GA 30365,
Phone: (404) 347-2913. Allen Antley
V. 230 S. Dearborn Street. Chicago O. 60604.
Phone: (312) 353-2152. E.1 Watten
VI. 1445 Rosi Avenue. Da lai. TX 75202,
Phone: (214) 255-7155. Tom Love
VII. 72& Minnesota Ave.. Kansas City, KS
66201. Phone: (913) 551-7032. Ralph
Lcngemeier
VIII.. One Denver Place. 999 18th Street, suite
300. Denver. CO 80202-2413. Phor.e: (303)
293-1408. Patrick Crotry
IX. 215 Fremont Street. San Francisco, CA
94105, Phone: (415) 974-0912, Steve
" Pardieck
X. 1200 Sixth Avenue. Seattle. WA 88101.
Phone: (208) 442-4092, Jan Hasting*
Abbreviations Us»d in This Document
AA: Direct Aspiration Atomic Absorption
Spectroacopy
ADI: Adjusted Daily Intake
BAT: Best Available Technology
BTCA: Bent Technology Generally Available
CAA: Clean Air Act
CAG. Cancer Assessment Group
CRAVE: Cancer Risk Assessment
Verification Endeavor
CUR: Carbon Usage Rate
CWS: Community Water System
DWEL: Drinking Water Equivalent Level
EBCT: Empty Bed Contact 'Time
ED: Electrodialysis
EDR: Electrodialysis Reversal
EMSL: EPA Environmental Monitoring and
Support Laboratory (Cincinnati)
FmHA: Farmer's Home Administration
GAC: Granular Activated Carbon
GFAA: Graphite Furnace Atomic Absorption
Spectroscopy
ICP-AES: Inductively Coupled Plasma-
Atomic Emission Spectroscopy'
E: Ion Exchange
rMDL: Inter-Laboratory Method Detection
LJr.iit '
IOC: Inorganic Chemical
LOAEL: Lowtst-Observed-Adverse-Effect
Level
LOQ: Lim;t of Quantity.ion
MBS: Multinational Business Services. Ir.c.
MCL; Maxirr.uar. Contaminant Level
(expressed as mg/1) '
MCLG: Maximum Contaminant Level Coal
MDL: Method Detection Limit
MCD: Million Gallons per Day
NAS: National Academy of Science
NIPDWR: National Interim Primary Drinking
Water Regulation
MIST: National Institute of Standards and
Technology
NOAEL: No-Observed-Adverse-Effect Level
NORS: National Organic Reconnaissance
Survey
NPDWR:'National Primary Drinking Water .
Regulation
NSF: National Sanitation Foundation
NTW'S: Non-Transient Non-Community
Water System
OPP-. EPA's Office of Pesticide Programs
PAP: Polymer Addition Pracucet
PE: Performance Evaluation
POE: Point-of-Entry Technologies
POU: Point-of-Use Technologies '
PQL: Practical QuantitaticT Level
PTA: Packed Tower Aeration
PWS: Public Water System
R£D: Reference Dose (formerly termed
Acceptable Daily Intake (ADI))
RIA: Regulatory Impact Analysis
RMCL: Recommended Maximum
Contaminant Level
RO: Reverse Osmosis
RSC; Relative Source Contribution
SOW A; Safe Drinking Water Act or the
"Act." at amended in 1986
SMCL: Seoonaary Maximum Contaminant
Level
SOC Synthetic Organic Chemical
TEM: Transmission Electron Microscopy
THMi: Trihalometh«ne«
TON: Total Odor Number
TWS: Transient Non-Community Water
System
UV: Uncertainty Factor
UIC: Underground Injection Control
VOC: Volatile Organic Chemical
WHP: Wellhead Protection
LUtofT«Mw
Table 1—MCLCs and MCLa for Inorganic
Contaminants
l nuUi$r«ni (mj).
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Federal Register / Vol. 56. No. 20 / Wednesday. January 30, 1991 / Rules and R&gulations 3527
Table 2—MCLC» and MCLs for Volatile
Orgaruc Contaminants . .
Table 3—MCLGi and MCLs for Pesticides/
PCB«
Table 4—MCLGs and Treatment Technique
Requirements for Otner Organic
Contaminants
Table 5—Secondary Maxirtum Contaminant
Levels (SMCLs)
Table 6—Eest Available Technologies to
Remove Inorzan'c Contaminants
Table 7—Be;t Available Technologies to
Remove Synthetic Organic ContaminanU
Table 6—Compliance Monitoring
Requirements
Table 9—Analytical Methods for Inorganic
Chemicals
Table 10—Analytical Methods for Volatile
Organic Chemicals
Table 11—Analytical Methods for Pesticides/
PCB»
Table 12—Laboratory Certific- . jn Criteria
Table 13—State Implementaticn
Requirement!
Table 14—EPA's Three Category Approach
for Establishing MCLCs
Table 15—Relative Source Contribution
Table 18—Inorganic Contaminant
Acceptance Liirits and Practical
Quantification Levels
Table 17—Inorganic Contaminant Sample
Preservation. Container, and Holding Time
Requirementj
T«bl« 18—Pesncide/PCB Practical
Quantitation Levels and Acceptance Limits
Table 19—Eectrodialysis Performance
Compared to Proposed BATs
Table 20—Additional Costs for Vapor Phase
Carbon Emission Controls for Packed
Tower Aeration Facility
Table 21—CAC and Packed Column Costs to
Remove SOCa
Tjble 22—MCL Analysis for Category I SOCs
Table 23—MCL Analysis for Category U and
III SOCs -
Table 24—Method Detection Limits—
Fesiicides/PCEa
Table 25— L'nregulated Inorganic and
Organic Contaminants
Tah'e 28—Section 1415 BAT for Inorganic
Contaminants •
Table 27—Section 1415 BAT for Organic
Contaminant!
Table 28—Summary Impact Estimates for
Final IOC and SOC. Regulations
Table 29—Comparison of Total Annualized
Costs for Proposed and Final Rules
Table 30—L'pper Bound Household Costs [$/
H-l/year)
SUPPLEMENTARY INFOKMAT1OK:
Abbreviatjoas Used In This Document
Liat of Taole*
T*ble of Contents
I Scaimtry of Today's Action
II. Background
A. Statutory Authonry
B. Regulatory History
C. Public Comments on the Proposal
in. Explanation of Today's Acaon
A. Establishment of MCLGs
1 How MCLGi Art Developed
2 Response to Comments on EPA B Zero
S1CLG Policy
3 Relative Source Contribution
4 Inorganic MCLGs
a. Asbestos ..
b. Cadmium
c. Chromium
d. Mercury
e. Nitrate/Nitnte
(!) Nitrates and Cancer
(2) Other Effects
(3) Other Issues
f. Selenium
5. Volatile Organic Contaminants (VOCi)
MCLGs
a. cis-1.2-Dichloroethylene and truu-1.2-
Dichlojoetfcylenfi
b. 1.2-Dichloropropane
c. Ethylbenzer.e
d. Monochlorobenzene
e. ortho-DicfllarobenreTie
f. Styrene
g. Tetr&cble-oethyler.e
h. Toluene
i. .Cylenes
P. Pesticides/PCBs MCLGs
a. Alachlor
b. Atrazir.e
c. Carbofuran
d. Chlordane
e. l.2-Dibromo-3-chionpropane (DBCP)
f. 2.4-D
g. Heptachlor/Heptachlor Epoxide
h. Lir.dane
i. Meth'oxychlor
j. Po'.ychlonnated Biphenyls (PCBs)
7. Other Synthetic Organic Contaminant
MCLCs
a. Acrylamide
B. Establishment of MCL»
1. Methodology for Determination of MCLs
2. Inorganic Analytical Methods
a. Asbestos
b. Nitrate/Nitrite
c. Other Inorganic Analyses
d. Method Detection Limits and Practical
Quantification Level
(1) Inorganics
(2) Nitrite
e. Inorganic Chemical Sample Preservation.
Container, and Holding Time
3. SOC Analytical Method*
a. VOC Methods
b. Method Availability
c. Cleanup Procedures
d. Pesticide Methods
e. Method 525
f. PCB Analytical Methods
g. VOC Performance Studies
h. Pesucide/PCB PQL and Performance
Acceptance Limits
4. Selection of Bost Available Technology
a. Inorganics
b. Synthetic Organic Contaminants
(1) Why PTA Is BAT for Air Stripping
(2) PTA and Air Emissions
(3) BAT Field Evaluations
(4) Carbon Disposal Costs
(5) Powdered Activated Carbon as BAT
(6) Empty Bed Contact Time
(7) Carbon Usage Rates
5. Determination of MCLs (Feasibility and
. Cost)
a. Inorganic Contaminant MCLs
b. Synthetic Organic Contaminant MCLs
(1) Category I Contaminant*
(2) Category D and IH Contaminants
C. Treatment Technique Requirements
D. Compliance Monitoring Requirements
1. Introduction
2. Effective Date
3. Standard Monitoring Framework
a. Three-. Six-. Nine-Year Cycles
b. Base Monitoring Requirements
c. Eight VOCs Regulated July 8,1987
d. Increased Monitoring
e. Decreased Monitoring
f. Vulnerability Assessments
g. Relation to the Wellhead Protection
Program
h. Initial and Repeat Base Monitoring
4. Monitoring Frequencies
a. Inorganics
(1) Initial and Repeat Base Requirements
(2) Increased Monitor.ng
(3) Decreased Monitoring
b. Asbestos
(1) Initial and Repeat Base Re'-iuirer-snts
(2) Increased Monitoring
(3) Decreased Monitoring
c. Nitrate
(1) Initial and Repeat Base Requirements
(A) Community and Non-Transient
Water Systems
(B) Transient Non-Community Water
Systems
(2) Increased Monitoring (CWS. NTWS.
TWS)
(3) Decreased Monitoring (Surface CWS
and NT/VS)
d. Nitrite
(1) Initial and Repeat Ba»e Requirementj
e. Volatile Organic Contaminant* (V.OCs)
(1) Initial and Repeat Base Requirements
(2) Increased Monitoring
(3) Decreased Monitoring
f. Pesticides/PCBs
(1) Initial and Repeat Base Fsquirementi
(2) Increased Monitoring
(3) Decreased Mor.uonng
5. Other Issues
a. Compliance Determinations
b. Confirmation Sample*
c. Composing
d. Asbestos
6. Unregulated Contaminant Monitoring
E. Variances and Exemptions
1. Variances
2. Point-of-Use Device*. Bottled Water, and
Point-ot-Hntry Devices
3. Exemptions
F. Labora'.O'y Certification
G. Public Notice Requirements
1. General Comments
2. Contamin-.r.;-Speci5ic Comments
a. Asbestos
b. Other Contaminants
H. Secondary MCLs
1. Organic*
2. Aluminum
3. Silver
a. Derivation of SMCL for Silver
I. State Implsmentation
1. Special State Primacy Requirements
2. State Recordkeeping Requirements
3. State Reporting Requirements
IV. Economic Analysis
A, Ccst of Final Rule
B. Comparison to Proposed Rult
1. Monitoring Requirements
2. Charts* s in MCLa
3. Changes In Occurrence Data
4. Changes in Unit Treatment Cost
Estimates
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3528
Federal Register / Vol. 56. No. 20 / Wednesday. January 30, 1991 / Rules and Reguia'.ur.s
0 Cost 'o S>ste.T3
D Coal to Slate Progr
V O'her Requirements
A, Regulatory Flexibility Anal>s;s
B Paperwork Reduction Act
VI. Public Docket and References
I. Summary of Today'i Action
The effective date of this rule .3 July
30. 1092.
TABLE 1.—MCLGs AND MCLS FOR INORGANIC CONTAMINANTS
MCLGs
I
MCLS
!<)
(2) Cadmium '
13) Clvomium
,41 Mercury
,51 Nitrate
(6) Nitrite
<~1 Total titrate and Sttrte
7 million fibers.'liter (longer tfian '0 urn)
. 0005 mg/l
0 1 mg/l .... .
0002 mg/l
. 10 mg/l (as N)
, 1 mg/l (as N)
, 10 ng/l (as N)
1 0 05 mg/l ,
7 million fibers/liter (longer man 10 urn).
0005-mg/l.
O.t mg/l.
0 002 mg/l
10 mg/l (as N).
1 mg/l (u N).
10 mg/l (as N).
0 05 mg/l.
TABLE 2.—MCLGs AND MCLs FOR
VOLATILE ORGANIC CONTAMINANTS
TABLE 3.—MCLGs AND MCLs FOR
PESTICIDES/°CBS
TABLE 4.—MCLGs AND TREATMENT
TECHNIQUE REQUIREMENTS FOR OTHER
I1! o-DicNorobenzere
Slcis-1 2-
DcnKxoemy'ene
i3l trars-1 2-
DicrvSoroerpy !*«•>«
(4) t 2-DtctikxCDroDana
• 5| EWytb«orwie
16)
MonocMorobenzene
1?) Styrene , ,
81 T«tracnkxo«tnyier>« .,
(3) Toluene , , ,
(10) Xy*en«4 itotal)
MCLGs
"Tig,".)
06
007
0 1
0
37
0 1
0 1
0
t
10
MCLs (mg/
1)
OS
007
01
0005
07
0 1
01
0005
i
'0
ii) Aiacnior
(2) Atrazine
(3) Carbofuran
(4) Chlordane . ...,
(5) 1,2-Dibromo-3-
cntorooropane (DBCP).
,6) 2 4-0
(7) Ethvlen* dtbromtd*
lEOB)'.
(8) Hepachlor
(9) Heotachtor epoxid« .
(10) Undane
(11) Methoxycnlor
ti2) Polvcrilonnated
oionenyis (PCSs) (as
aecacnlorooipnanvl).
i'4) 2.4.5-TP iSirvex)
MCLGs
uct »
6-
Treatment
tacnnqu*.
.
007I'/ TABLE 5.— SECONDARY MAXIMUM
OOOOC5. CONTAMINANT LEVELS (SMCLs)
O.OOO4. Aluminum
•0300Z- i)a£r
03002. *'
.1 0.05 to 0 2 mg/l.
....i 0.1 mg/1.
!
0.04.
00005.
0003.
005.
TABLE 6 —BEST AVA._-BLE TECHNOLOGIES TO REMOVE INORGANIC CONTAMINANTS
Be*t avai)a£)l« lecnnotogws
-jnur"> . - - n. ~~ n,.t^,n. i Grtnulw
„ '• Ac^vatod wGaou^atiO'' _orros*ori Lfcreci L"aiomne activated
">n a-um^ra 'ifvaoor * v control hltraDon hft'aoon , cartxyi
*,3«S!H X X X - X
Hart.ni '
j
C^rorrujm ^ . '
.
Vf-w- \ • ' ' X
s w *•** '' '
s ' ' '
3«^m XX' :
'' ' 1
-. '*" • i
««.»•>.' - is •
.1 . i
•4te, i
Ion • Lime j
excr.ange ; sotter«r>g »
X • X
X ', X *
x ! x
,
x ;
'x-
X :
X 1
IX
i
!
' X ' X
i • .
1 1
:
Reverse
osmosis
x
Electro-
dofysu
X
X
1
X
X '
X
X
X
X
X
X
SAT VN r/ ^H^t -^c-^ conc.r^.000, do not «c*»d '0 Mg/l, CoaguiatKjn/fittraoon lor r-srcury -*noval *v^d- PAC addrbon or port-filrttxjn GAG
't'-"** w~^t> 'vj'* or9*r«c rrxrcuor ^ pr»*«rrt pr source w«t»r
1 Set ' *' 5 B> T 'or i/naX fyitafTt for van«.ic*« ufrt«M trsatnent ts currentf^ in place.
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Federal Register / Vol. 56. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations • 3529
TABLE 7.—BEST AVAILABLE TECHNOLOGIES TO REMOVE SYNTHETIC ORGANIC CONTAMINANTS
Cftamcal
GAC'
PTA •
PAP <
voc*
CJ*-t.2-OicNoroatrrvi«oe ........ ;
trans-1.2.-O«cMoro«mylene .......... ...
1 ,2-C>cnloroprooar>e ..........
MonocNorobetuene
...................................... -, .,
Tetrecftloroemyleoe .............. .. ............................................. , ...... • *
Toluene [[[ ...... ........ ; ............................ * '
Xylene* (ToUl) [[[ ........... v. ....... I X
Pestxaclea/PCBs: |
Aiacfikx.. [[[ I X
AMicarb ........................ . [[[ ! X
Ak»cart> iurlooe .............................................. , .............. , ..................... ' X
AJdicarb aurtaode [[[ j X
Atrazne [[[ : ................. i X
Caftoohxar) .............................. . .............................................. i ............... ' X
CNcrtane .............................................. . ................................................ j X
2.4-0 [[[ X
r>b!XXTX>cNoroprop«ne (DBCP) [[[ • X
Etnytene Obromioe (EDB) [[[ X
HepttcNor [[[ X
Heptachtor epomde [[[ , .......... X
IJndane ......................................... , ............. ...-., ........................ •-•,, ....... ! x
M«hoxycMor [[[ ! X
' PCS. [[[ X
X
! X
X
X
i x1
Ix
> X
X
X
X
2.4.5-TP (
Toxapft*rw .........................
Othv Ory*nc Contemnanta:
1 GAC = Granular activated cartion.
• PTA - Pscfccd towvr MraDon.
' PAP = PtxymK addmon p*»cac«t
TABLE 8.—COMPLIANCE MONITORING REQUIREMENTS
Contaminant
j Base requrement
j Ground water
! 1 sample/3 yr
1 t*mnl«/Q v«jira attar 3
Surface water
AnnuaJ s/imple
umotM < MCL
Tngoer that increase* monrtonng
>MCL
Waiver*
Yes: Based -on analytical results o<
**..«* ................... : ......................... 1 Mnvi* av«y 9 year,
AnnuaJ Ouartar'y
3 rounds.
on vulMrtMly ass««-
10 vOCa
18 f
! Altar 1 y»ar <50N MCL. SWS. may reduca to an ; >SO% MCL... ........................................ , No.
I annual umola. I I
50% MCL ........................................... No.
r; anrx^ a«ar on. yw of no detect: >0.0005 mg/l ........................................ ! Yet Ba«d on vulr^ab-l.ty
. PC3s
av«ry 3 years
round*.
ment
.! 4 quarterly »amptaa. every 3 yri; ««ar 1 round of no ; Datactxjn. (SM Table 23) j Yea: Oaaed on vuJneraMlity a««ss-
i detect i>s 3,300 reduoi to 2 iamptea/vr I m«rrt-
I every 3 yrt. »y»Wma <3.300 r»duca to 1 sample
every 3 yrs.
-vac.uialec: !
-6 IOC». - 24 SOCi : One tample. 4 conaecutrve qi-«niK»
..: N.A.
Yea: Based on vulnerability
Table 9. — A-nalytical Method* for
Inorganic Chemicals
Alumuium:
A.::-— '. absorption, furnace techn:q'.e
L.nr-..!r Fcmice A:oz,c Abiorplion
»c'_-c?ccp> :CFAA).
Aiomic absorpfon. direct aspiration '
Asbestos
Transmission electron microsccpy
Banum:
Atomic absorption: furnace tec.inique '
Atomic absorption: direct aspr ation *
' Direct Aipira'jon Atonic Ab»or jtion
Sp«ctro«copy (AAJ.
Lnductively coupled plasma /3/
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3530 Federal Register / Vol. 56. No. 20 / Wednesday, januan, 30. 1991 / Rules
TA6t_E 12.—LABORATORY
CRITERIA
IOC>
Manual cold vaoor lechique
Automated cold vapor !echn:q,-«
.V.trale:
Manual cadmium reduction
Automated h>dra::r.e reduction - Asoestos 2 surxH'S
Automated cadmium reduction &as»d o" jtuay nat-
ion selective e>c::oJ! act
Ion chroma-OS-;!"- Banum .. ='5'. at ..3 -5 mg'1
S-.U-te- -Cadmium ............. r2CS at > 002 mg/l
' Chromium ..... , , ±15% at >001 -ng.'t
.: ^% .; y^;:
. . - ,0% at ,0 * mg/l
Ion chrotr\a:.-graphy NrtrJt ' .......... = is». at >0« mg/i
Selenium; . - s«Wmu:ii , .! ^20% at ^0 01 mg/l
Atomic abno.-p'.ion. gttseoui hydride vOCs: j
Atomic absorption, furnace ' ' . -20% at >O.OiO mg/l
S.lver ! -*0'1' •' <00i0mg/i
Atomic ahtorption: direct aspiration * PosscKfca and PCS* i
Inductively coupled plain:- » AiacWor ................... ±«S% •« ° °°2 mg/ .
Atfttn* ....,! ±45% at 0 001 mg/l *
TABLE iO.-ANALrr.CAL METHODS FOR %»*£ ............... ; z^X^ ,
VOLATILE ORGANIC CHEMICALS H«puct*x ... .......... ±«s% at o ooo« mg/i
__ __ Hsptacfrtof I =*5% «t 0.0002 mg/1 ;
EPA m«mod» Comamt-apts apowJ*. |
. - — Undone ............. ...... I = *5% at 0 0002 mg/l
^ • Matttoxycr y ........... ! ±*5H «: 0 01 n-g/1
502 1 ....... .... c-Ootoroocnzwi* pj.^ . | 0.200% ,1 0.0005 rr^.M I
5022 ,.,.„,„... ca-l^-DcWoro«mYie«. r^cicWoroe.- ' I
503 1 ... ....... . tran»-<,2.-Dic«oro«tnyier«. onwryl) '
52-" ..» ...... 1.2-Ocr.kxoprcparw. AloWrt ' ........ =S5S at 0.003 mgrt
52* 2 , , ., , . , El»ytt>«oz«o«, Alocart) *ultO)«i« ....! ±55N at 0.003 mgn
Mooocr>kx3C«o«n. AWlcart) ^^ ....... 1:S5% ., o 003 mg/1 :
, St>rr»n«. Toxaofwp* . .... ..... r*S% at 0.003 mg/t
: Tat,«rUofo.!nylen. P,mi:Wo7opn«x.:...i =50% at 0.001 mg/l
2 4 o .............. ........... ±50% „ 0 005 p^/,
2.X.5-TP ....... _ .......... ! =50% at OOOSmg/1 !
-- - - • ED6 ;» 40% al 000005 mg/1
TABLE 11.-ANALrT.CAL METHODS FOR • "^ .......... - -^ '^ " OOOCi ^ •
PEST.CIDES/PCBS ,
____ __ _ . TABLE t3.— STATE 1MPLEMEMTATK3N i
EPA mauxxsi Contaminanti REQUIREMENTS i
504
JCS
. CXxomocnkxotxooan*
! Prxnacy
AlacMor
Atrazm*.
apcutM,
M«moxycMor.
Vulrwadtty 1 X
prewKluw ' '
! X
507
SCfl
508A
5151 . ..
PC8»'
, A'tcMor
Airaiin*,
Cwcrtana.
Monitoring X
scf*duJ«. I
VulrwrmMity i
txx*.
Watven granted..
MeOxwycNor.
PCBi1
PC8« (ai
2.*-0.
2.4.S-TP CS*.«-
c*lrt>c»non». ;
Jmgutatad
cootanvnam
S25
.......... AiacJMOf.
Atr«ao«.
Chkxoan«.
Aloc*rt>
AKkcot: tulon*.
Cartjoturmn.
tt 9o-*ctt£ o 505 or
j3.no Mrnxxl 506A.
5O6
most
» SUtc* grant waivcn.
n. Background
X. Statutory Authority
The Safe Drinking Water Act (SDWA
or "thje Act"), as amended in 1986 (Pub.
L, No. 99-339.100 Stal. 642), requires
EPA to publish "maximum contaminant
level goals" [MCLGs) for contaminants
which, in the judgment of the
Administrator, "may have an adverse
effect on the health of persona and
v\h;ch (are) known or anticipated to
occur in publ.c water systems" (sec1..: n
1412(b)(3!(A)). MCLGs are to be se'. at a
level at which "no known or anticipatpd
adverse effects on the health of persons
occur and which allow* an adequate
margin of safety" (section 1412(b)(4!l
At the same time EPA publishes an
MCLG, which ia a non-enforceable
health goal, it must also promulgate 3
National Primary Dnnkmg Water
Regulation (NPDWR) which includes.
either (1) a maximum contaminant level
(MCL). or (2) a required treatment
technique (section 1401(1). 1412(a)(3).
and 1412(b)(7)(A)). A treatment
technia-f c"iy be set only if it » not
"econorrical'y or technologically
feasible" to ascertain the level Of a
contaminant (sections 1401(1) and
1412(b)(7)(A)). An MCL must be set as
close to the MCLG a< feasible (section
1412(bK4)j. Under the Act. "feasible"
means "feasible with the use of the best
i technology, treatment techniques, and
• other means which the Administrator
finds, after examination for efficacy
'• under field conditions and not solely
under laboratory conditions, are
available (.taking cost into
: consideration)" (section 1412(b)(5)). In
setting MCLs. EPA considers the cost of
. treatment technology to large public
water systems (i.e.. > 1.000.000 people)
j with relatively clean source water
supplies (132 Cong. Rec. S6287 (daily
1 ed.. May 21.1986)). Each NPDWR that
j establishes an MCL rnuat lift! the best
1 available technology, treatment
1 techniques, and other means that are
i feasible for meeting the MCL (BAT)
j (»ectkm «412(b)(B)|. NPDWRs include
, monitoring, analytical and quality
I assurance requirements, specifically.
i "criteria and procedures to assure a
supply of drinking water which
! dependably complies with such
i maximum contaminant levels * * *."
! (Section iwi(lMD))- Section 1445 also
j authorize* EPA to promulgate
; monitoring requirements.
\ Section 1414(c) requires each owner or
operator of a public water system to
i give notice to persons served by H of (1)
' any failure to comply with a maximum
j contaminant tevel, treatment technique,
or testing procedure required by a
, NPDWR; (2) any failure to comply with
any monitoring required pursuant to
section 1445 of the Act; (3) &e existence
of a variance or exemption: and (4) any
failure to comply with the requirements
of any schedule presc; 'led pursuant 11 a
variance or exemption.
Under the 1986 Amendments to the
SDWA. EPA was to complete the '
promulgation of NPDWR* for 63
contaminants, in three phas«s, by June
-------
Faderal Ragstef / VoL 56. No. 20 / Wednesday. January 30. 1981 / Rules and Regulations 3531
19. 1989. After 1989, an additional 25
contaminants must be regulated every
three years (section 1412(bJ).
B. Regulatory History
In the 1986 Amendments to the
SOW A. Congress required that MCLGs
and MCLs he proposed tod promulgated
simultaneously (section 14±2(a)(3)). This.
change streamlined development of
drinking water standards by combining,
two steps ia the regulation development
process. Section 1412(a){2) renamed •
recommended maximum contaminant
levels (RMCLi). as m««-imimi
contaminant level goals, (MCLGs).
To insure compliance with th«
provision that MCLGs and MCLs be
proposed and promulgated
simultaneously and to ensure adequate
opportunity rbrpoblic comment on these
proposed standards, EPA proposed as
RMCLs. in November 1985, most of the
MCLGs contained in today's rule.
On May 22. 1888. ETA proposed
MCLGs sssd; MCL* for 38. centamiuat*
and a toeatnsatit tBeknufos)
for two eontmninnnfft. Moot of the
MCLGs and MCL* are proinnlgirted *t
the same level* as proposed la May
1989. However. the MCLGs aad/of
MCLs for five contaminants are, lower
than, previously proposed. Whore EPA is
promulgating MCLGsi MCLs. analytical
methods,. best available technology,
monitoring requirements,, aad State
implementation requirements that differ
from the proposal, the changes result
from public comments and/or additional
data mat the preamble indicated were
under development or snsfyste. The
technical and/or policy basis for these
changes are- explained m this, notice.
On February 14. 1989. ia- response to a
citizen auii from the Buil ROB, fj^titinn,
EPA entered ixto s consent order which
requires promulgation of regulations: for
40 contaminants by December 31, 1990.
EPA OB IVUM IS. 1888- partially fulfilled
this requirement by promulgating
regulations on colifonna and other
microbiologicaL
promulgation of regulation* on the 34.
contaminants ia today's rule partially
fulfills the terms of the consent decree.
Because of changed RfOs for aldfcarb,
aldicarb suifoxide, aldicarb sulfone, and
barium and the reclassification of
and placement in Category I EPA.
elsewhere in today's Federtl Register, is
reproposing the MCLGo and MCLi for
these fnntBminiivts .
(the RfD adjusted for an adult drinking
an *verag» of 2L water/ day over a
lifetime] 5 adequate det» exist. To
accoant for possible careinofemeity, an
additional ancertaisrty factor wf up to tt>
is applied. If adequate noBcarcmogerac
data ata sot avaUabte (Lew «»be«to»>,
the, seoond optioit consists of sitrttng the
MCLG in the theoretical «xcaso cancer
risk range of 10" • to WT». EPA te
currently evaluating the appropriatenes*
of the tw& option* for establishing
MCLGe fsee 55 FR 3037ft p. 3O4O4).
However, the MCLG* proawIgiHed
today m«e the RfD option wrtb im
application of an »J*tion*l ancerrairrty
factor np to 10, except es noted for
asbestoe.
1. How MCLGs Are Developed
MCLGs are set »t concentration- levels
at which no known or antfcipafveT
adverse health effects would occur,
allowing for as adequate margin of
safety. Establishment of a specific
MCLG depends OB the evidenco- of
carciaogeHicity fron» driakiag water
exposure or the Agency's relrreoee- dose
(RfDJ , wkics is. eafcoJated for each
The cancer classiScatiun for a spedfic
chemfcai and the reference dos« are
adopted by two dlflereul fiyemy groups.
Decisions on cancer classifications are
made by the Cancer Risk Assessment
Verification Endeavor (CRAVEf group.
which is Luuiyostd of representatives of
various EPA pmgiaui offices. Decisions
on EPA reference, doses, (using non-
cancer endpoints ordy] an made.
through the Agency Reference Dose
work giuup. also composed of
represenlatires of various EPA program
offices. Decisions by CRAVE and the
RfD groups represent policy decisions
for the Agency and are used by the
rcguiai lory pro^^fiuT» &• LUB
basis for regulatory decisions. Decisions
of these two groups are published in the
Agency's Hrtegrsted Risk Information
System C1^1^)- This system can be
accessed by the public ky convicting
Uik* McLa^hha of DtALCOM; toe. at
i*o
raised and no new information was
obtained by the Agency that would
cause it to change the MCLGs from the
The RfD is an estimate, with an
uncertainty spanning perhaps in order
of magnitude, of a daily exposure to the
-------
3532
Federal Register /.Vol. 56, No. 20 / Wednesday. January 30. 1991 / Rules and Regulations
human population (including sensitive
subgroups] that is likely to be without
an appreciable risk of deleterious health
effects during a lifetime. The RfD is
derived from a no- or lowest-observed-
adverse-effect level (called a NOAEL or
LOAEL. respectively) that has been
identified from a subchronic or chronic
scientific study of humans or animals.
The NOAEL or LOAEL is then divided
by the uncertainty factor to derive the
RfD.
The use of an uncertainty factor is
important in the derivation of the RfD.
EPA has established certain guidelines
(shown below) to determine which
uncertainty factor should be used:
10—Valid experimental results for
appropriate duration. Human exposure.
100—Human data not available.
Extrapolation from valid long-term
animal studies.
1.000—Human data not available.
Extrapolation from am nal studies of
less than chronic exposure.
1-10—Additional safety factor for use
of a LOAEL instead of a NOAEL.
Other—Other uncertainty factors are
used according to scientific judgment
when justified.
In general, an uncertainty factor is
calculated to consider Lntra- and
intenpecies variations, limited or
incomplete data, use of subchronic
studies, significance of the adverse
effect, and the pharmacokinetic factors.
From the RfD. a drinking water
equivalent level (DWEL) is calculated
by multiplying the RfD by an assumed
adult body weight (generally 70 kg) and
then dividing by an average daily water
consumption of 2 L per day. The DWEL
assumes the total daily exposure to a
substance is from drinking water
exposure. The MCLG is determined by
multiplying the DWEL by the percentage
of the total daily exposure contributed '
by drinking water, called the relative
source contribution. Generally, EPA
assumes that the relative source
contribution from drinking water is 20
percent of the total exposure, unless
other exposure data for the chemical are
available. The calculation below
expresses the derivation of the MCLG:
RfT> =
DWEL =
NOAEL or
LOAEL
uncertainty
factor
RfD X body
weight
daily water
consumption
in L/day
mg/kg/
body
weight/
day
ID
(2)
MCLG = DWEL x drinking water
contribution (3)
For chemicals suspected as
carcinogens, the assessment for
nonthreshold toxicants consists of the
weight of evidence of carcinogenicity in
humans, using bioassays in animals and
human epidemiological studies as well
as information that provides indirect
evidence (i.e.. mutagenicity and other
short-term test results). The objectives
of the assessment are (1) to determine
the level or strength of evidence that the
substance is a human or animal
carcinogen and (2) to provide an
upperfaound estimate of the possible risk
of human exposure to the substance in
drinking water. A summary of EPA's
carcinogen classification scheme is:
Group A—Human carcinogen based
on sufficient evidence from
epidemiological studies.
Group Bl—Probable human
carcinogen based on at least li-nited
evidence of carcinogenicity to humans.
Group B2—Probable human
carcinogen based on a combination o£-
sufficient evidence in animals and
inadequate data in humans.
Group C—Possible human carcinogen
based on limited evidence of
carcinogenicity in animals in the
absence of human data.
Group D—Not classifiable based on
lack of data or inadequate evidence of
carcinogenicity from animal data.
Group E—No evidence of
carcinogenicity for humans (no evidence
for carcinogenicity in at least two
adequate animal tests in different
species or in both epidemiologies) and
animal studies). «.
Establishing the MCLG for a chemical
is generally accomplished in one of
three ways depending upon its
categorization (Table 14). The starting
point in EPA'i analysis is the Agency'.
cancer classification (i.e.. A, B. C. D, or
E). Each chemical is analyzed for
evidence of carcinogenicity via
ingestion. In most cases, the Agency
places Group A. Bl. and B2
contaminants into Category I. Group C"
into Category II. and Group D and E into
Category HI. However, where there is
additional information on cancer risks
from drinking water ingestion (taking
into consideration weight of evidence,
pharmacokinetics and exposure)
additional scrutiny is conducted which
may result in placing the contaminant
into a different category. Asbestos and
cadmium are examples where the
categorization was adjusted based on
the evidence of carcinogenicity via
ingeation. In the case of chromium,
where there is uncertainty in the
ingestion data base, the Agency used
the RfD approach (described below) to
derive an MCLG even though the
chemical has not been categorized. This
issue is discussed below. Where there is
no additional information on cancer
risks from drinking water ingestion to
consider, the Agency's cancer
classification is used to categorize the
chemical. In the cases of styrene and
tetrachloroethylene. where the Agency's
cancer classification is unresolved. EPA
used its categorization approach to
derive an MCLG.
EPA's policy is to set MCLGs for
Category I chemicals at zero. The MCLG
for Category II contaminants is
calculated by using the RfD/DWEL with
an-added margin of safety to account for
cancer effects or is based on a cancer
risk range of 10"» to 10"4 when non-
cancer data are inadequate for deriving
an RfD. Category III contaminants are,
calculated using the RfD/DVvtiL
approach.
TABUE 14.—EPA's THREE-CATEGORY APPROACH FOR ESTABLISHING MCLGs
Ca-eoo-t
1
II „ . „
II!
Evidence at caranogen
Strong evidence cormdenng weight of
expoem.
Limited evidence con»>denng 'we^ht of
Inadequate or no emmal evidence
crty via rvqection
evidence, pnarmacokneoci, and
evidence, pnarmaco kinetic*, and
Zero,
RfD approach wt
RfD approach.
MCLG Mtting approach
(ft added »a(ety margm or 10"' to 10'« cancer riak range
-------
Federal Raster / VoL 56. No. 20 / Wednesday, January 30, 1981 / Rules and Regulations-.
3533
The .MCLG for Category I
contaminants i* set at zero because it is
assumed, in the absence of other data,
that there is no known threshold.
Category I contaminant* are those
contaminants which EPA has
determined that there is strong evidence
of ca.-cinogemci'y from dnnking water
ingestion. If there is no additional
information to consider on potential
cancer risks from drinking water
ingestion. chemicals classified as A or B
carcinogens are placed in Category I.
Category n contaminants include
those contaminants which EPA has
determined that there is limited
evidence of carcinogenicity via drinking
water ingestion considering weight of
evidence, pharmacokinetics. and
exposure. If there is no additional
information to consider on potential
cancer risks from drinking water
ingestion, chemicals classified by the
Agency as Group C carcinogens are
placed in Category D. For Category D
contaminants two approaches are used
to set the MCLGs—either (') setting the
goal based upon noncarcinogenic
endpoints (the RfD) then applying an
additional uncertainty (safety) factor of
up to 10 or (2) setting the goal based
upon a nominal lifetime cancer risk
calculation in the range of 10"' to 10~*
using a conservative calculation model.
The first approach i» generally used-.
however, the second is used when valid
noncarcinogenicity data are not
available and adequate experimental
data are available to quantify the cancer
risk. EPA is currently evaluating its
approach to establishing MCLG* for
Category C contaminants.
Category III contaminants include
those contaminants for which there U
inadequate evidence of carcinogeniciry
via ingestion. If there is no additional
Information to consider, contaminants
classified as Group D or E carcinogens
are placed in Category QL For that*
contaminants, the MCLG is established
using the RfD approach.
2. Response to Comments on EPA's Zero
MCLG Policy
The purpose of MCLGe under th«
SDVVA is to set goal* for both
carcinogens and noncarcinogeas, at a
level at which "-no known or anticipated
adverse effects on the health of persons
occur and which allow an adequate
margin of safety." SDWA section
1412(b)(4). In its ruiemaking on volatile
syniheUc organic chemicals (VOCs), the
Agency articulated its policy of setting
MCLG» at zero for known and probable
human carcinogens. See 47 FR 9360
(March 4. 1982), 4ft FR 24336, at 34343
(June 12. 19844 and 50 FR 46880, it +6806
(Nov. 13, 1985}. Mullinationai
Services, Inc. (MBS) asked the Agency
to reconsider this policy which MBS
considered a departure from the
consistent application of nsk
assessment principles by federal
agencies in regulating carcinogens.
Instead. MBS recommended that EPA
establish MCLGs for such contaminants
at calculated negligible rwk Levels. In
the May, 1989 proposal of today's rule.
the Agency indicated that it intended to
continue the zero MCLG policy. At the
same time, the Agency agreed to
address the MBS request and any other
comments on the policy.
In the VOCa ruleraaking. the Agency
considered three major option* (and
several varie'iona) for setting. MCLGs
(then called "recommended maximum
contiHiinant levels") for the
carcinogenic VOGs. These were: zero
MCLGs. MCLGs set at the analytical
detection limit, and MCLGs set nl non-
zero levels baseo on calculated
negligible contribution to lifetime risks.
(50 FR 46880. at 46884.) The Agency
recognized that humans can tolerate and
detoxify a certain threshold level of
noncarcinogens, and therefore found it
appropriate to set MCLG* for ths
noncarcinogenic VOCs above zero.
However, in the .Agency's view a
threshold for the action of potential
carcinogen* could not be demonstrated
by current science: it was conservatively
assumed that no threshold exisU, absent
evidence to the contrary. Id Any
exposure to carcinogen* might represent
some finite level of risk, the magnitude
of which would depend on dosage aod
potency of the particular carcinogen.
Under these circumstances* in the
Agency'* judgment;'in MCLG above
zero did not meet the statutory
requirement that the. goal be set where
no known or anticipated adverse effect*
occur or allow an adequate margin of
safety.
The Agency believed that MCLGs of
zero for the carcinogens would also best
reflect the Agency's general philosophy
that, as a go«L carcinogen*1 should not
be present in drinking water. Moreover.
the legislative history of the SDWA
specifically authorized this regulatory
option. "The fMCLG} must be setto^
prevent the occurrence of any known or
anticipated adverse effect It mu*t
include an adequate margin of safety,
unless there is no safe threshold for a
contaminant In such a case the (MCLG)
should be set at tht zero level" [Hit
Rep. No. IW6, 93d Cong,, Z± Set*. 20
(1974), reprinted in "A Legislative
History of tile Safe Drinking Water Act'
1982 at 562.} EPA'i decision to-
promulgate zero MCLGs far the
carcinogenic VOC» was aptekr in the
"VOCs decision." Natural Resources
Defense Council v. Thomas. 824 F.2d
1211 (B.C. Cir., 1987). (EPA's
determination was "well within the
bounds of its authority" under the
SDWA. Id. at 1213).
Comments on the zero MCLG issue in
the May 1988 proposal were received
from eighteen commenters in addition to
MBS. Virtually all of the issues in these
comments have been raised and
addressed earlier See 49 FR 24330 (June
12. M84) and 50 FR 46895 (Nov. 13.1985).
MBS and other commenters disagree
with the Agency's interpretation of the
statutory standard to set MCLGs at a
level to prevent the occurrence of any
known or anticipated advenie health
effect; with an adequate margin of
safety. These commenters argue that
Congress in*»"Hgd MCLGs to give
"reasonable." not "absolute." assurance
against adverse heaM effects. MBS and
others maintain that health effects are
not "anticipated" absent evidence
indicating they should be expected. We
note that Ae House Report cited earlier
indicate* that "the Administrator must
decide whether any adverse effects can
be reasonably anticipated even though
not proved to exist" H.R. Rep. No. 1185.
id. Some commenters are critical of the
Agency's "reliance" on the House
Report language addressing the situation
whew there is no known safe threshold.
These commenters argue that EPA's
interpretation is "inconsistent" with
other legislative history. MBS, for
example, cites the House Report
discussion of a study to be conducted by
the National Academy of Sciences
(NAS) to support its position that
Congress did not intend MCLGs to be
set at zero. The Committee directed
NAS to develop recommendations of
maximum contaminant levila "solely oa
considerations of pjblic health" and not
to be "influenced by political budgetary,
or other considerations," Id., at 551. In
recommending an adequate margin of
safety. NAS was to consider, among
other factors, the margin* of safety used
by other regulatory systems. Id ,.
Howsver, as the Committed made clear,
determining an adequate margin of
safety wa* but the final step in the
process of setting an MCLG. The
Administrfctor must first decids if any
adverse health effect* can reasonably
be anticipated, *ven though not proved
to exist. It was necessary to determine
an adequate margin of safety only if
there is a **** threshold for the
contaminant If mere is no safe
• threshold, the MCLG "should be set a.
the zero towL" U. at 552. We find ,
nothing in. the discussion of the NAS
study to contradict the Committee's
-------
3534 Federal Register / -Vol. 56. No. 20 / Wednesday, January 30. 1991 / Rules and Regulations
explicit recognition of the fact that there
may be circumstances where there is no
safe threshold for a contaminant.
Some commenters maintain that the
Agency'i interpretation of the SDWA
should be determined by interpretations
of other statutes that direct agencies to
set "safe" standards. In this regard.
several commenters point to the "vinyl
chloride decision" construing section
112 of the Clean Air Act (CAA). Batumi
Resources Defense Council. Inc. v. EPA,
824 F.2d 1146 (D.C. Cir. 1987). Pursuant
to section 112 of the CAA. the
Administrator sets emission standards
"at the level which in his judgment
provides an ample margin of safety to
protect the public health." The court
found that use of the term "safety" is
significant evidence that Congress "did
not intend to require the Administrator
to prohibit all emissions of non-
threshold pollutants." 824 F.2d at 1153. ,
The court cited the Supreme Court's
"benzene decision" for the proposition
that "safe" does not meaa "risk free"
and that something is "unsafe" only
when it threatens humans with "a
significant risk of harm." Industrial
Unior. Dept, AFL-CIO v. American
Petroleum Inst.. 448 U.S. 607. 640 (1980).
MBS argues that the "vinyl chloride
decision" is particularly compelling
since the term "margin of safety"
appears in both section 112 of the CAA
and section 1412 of the SDWA.
However, the court in the "VOCs
decision" noted that the Supreme
Court's "benzene decision" was based
on "a close reading of the statutory
language of OSHA, which we note
differs significantly from the statutory
scheme that we confront in this case.
The OSHA language that the Supreme
Court interpreted as incorporating a
requirement of a finding of significant
r.sk directed the Secretary to set
standards 'reasonably necessary and
appropriate to provide safe or healthful
employment1. 824 F.2d at 1215-1216.
Accordingly, there must be a threshold
determination that the place of
employment is "unsafe" in the **nse
thai significant risks are present arid can
be eliminated or lessened by changing
practises. 824 F,2d at 1215. The court in
the ' VOCs decision" found that this
"significant risk" standard did not apply
to the Administrator's decisions to
regulate contaminants under the SDWA-
824 F2d 1211. 1216.
We have followed a similar restraint
in unpoiung interpretations from other
statutes on the basis that they are •
'analogous." I! remain* our view that
reliance on such interpretations a*
determinative of Congressional intent in
enact:r.g the SDWA is unwarranted.
Section m'oi the CAA and other
statutes cited by commenters are not
"the same as" section 1412 of the SDWA.
They do not have a two-step regulatory
process consisting of separate.
aspirational goals, followed by
achievable, enforceable limits.
Feasibility, cost and other 'actors may
be relevant to determining appropriate
enforcement levels under the CAA and
other statutes and may influence the
concept of "safety." Such factors are not
appropriate in setting MCLGs. Some
commenters point out that EPA has
determined that standard* refecting a
10~* to 10"* risk level are safe and
protective of public health even for
known or probable carcinogens under
other of its authorities. That is true, but .
such determinations are not inconsistent
with our position that MCLGs serve
fundamentally different purposes than
enforceable standards.
MBS and a few other comir.enters also
suggest that the Agency's general
assumption of no biological threshold of
effect for carcinogens is not appropriate.
MBS maintains there is "an increasing
body of scientific data" indicating that
substances that elicit carcinogenic
response in laboratory animals "actually
appear to have a threshold of effect for
humans." EPA will continue to solicit
the best scientific views and encourages
the public to provide such evidence to
the Agency for consideration. EPA
intends to set MCLGs based upon the
most current scientific data, and is open
to revising current levels based upon
new data.
Some comments indicate concern that
zero MCLGs are impractical since they
are unde tec table and unachievable. It
remains our view that MCLGs are, by
statute, different from enforceable
standards: as goals based solely on
health factors they need not be
measurable, affordable or achievable.
Some commenters maintain that even as
unenforceable goals. MCLGi have
serious practical implications. They
argue that ze^o MCLGs cause undue
' public alarm and will result in the
misallocation of funds to reduce certain
contaminants. We believe the
distinction between aspirational goal*
and standards enforceable under .the
SDWA is significant and
understandable. We also believe that
those whc adopt MCLG* for purposes
outside the SDWA or use MCLGs as
operational standards rather than
aspirational goals do so knowingly,
those decisions cannot influence the
Agency'! setting of MCLGi. In this
context some commenter* argue that
zero MCLGs will have dire financial
results for Agency clean-up actions. We
cannot agree with such a broad
prediction. EPA has determined that
MCLGs of zero are not relevant and
appropriate requirements for Superfund
cleanups. Contaminant levels of zero are
not consistent with cleanup objectives
of CERCLA. See 55 FR 8666. 8750 [March
8.1990).
Some commenters maintain that zero
MCLCs will necessarily drive MCLs to
increasingly stringent enforceable
standards as technology improves and
that such standards are not justified by
their health benefits. The SDWA
provides that MCL* shall be set as close
as feasible to the MCLGi, taking cost
into account. While it is true that an
MCL for a contaminant with a zero
MCLG has a greater potential to
ultimately be more stringent than an
MCL for a contaminant widi an MCLG
above zero, a number of factors are
considered in determining what
constitutes "best available technology"
on which to base the MCL*. Moreover.
while resources should be directed
toward highest risks, it seems premature
to conclude that the resources lhat may
be necessary to achieve such standards
would be misdirected.
In the opinion of EPA. Category I
contaminants meet the "no safe
threshold" test established in the House
Report. EPA does not automatically
place contaminants classified as Group
A or B carcinogens in Category I.
Additional scrutiny occurs to determine
what evidence exists of the chemicals'
carcinogeniciry via ingesn'on
considering pharmacokinetics, exposure,
and weight of evidence. If the additional
evidence indicates that the overall
evidence of carcinogenicity via ingestion
is limited or inadequate, then the
chemical will be placed in the
appropriate category and an MCLG is
calculated accordingly. For
contaminants placed in Category IL the
MCLG is based on non-carcinogenic
effects using the RfD approa-ch. An extra
margin of safety of 1- to 10-fold is used
to account for the possible carcinogenic
effects of these Category II
contaminants. If data are inadequate to
establish an RfD, then EPA uses a 10"*
to 10"' cancer risk range to establish the
MCLG. .
EPA recognize* that other Federal.
State and public health agencies have
used a risk-based approach fot
• regulating carcinogen*. A* discussed
above, EPA does use a risk-based
approach as an alternative methodology
for Category II contaminants when non-
cancer health effect* data are
Inadequate to establuh an RfD (i.e..
asbestos). Currently EPA i» considering
adopting this risk-based alternative as
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Federal Register'./ Vol. 56. No. 20 /Wednesday. January 30. 1991 / Rules and Regulations 3535
the primary approach for Category II
contaminants in future regulations (see
55 FR 30374. July 25.1990).
In addition, when EPA establishes .
MCLs, it considers the cancer.risk at the
MCL to determine whether they would
be acceptable from a safety standpoint.
A target risk range of 1CT4 to NT* is
considered by EPA to be safe and
protective of public health.
EPA agrees that MCLGs at zero do not
provide specific information on potency
and mechanism of action: however. EPA
does consider potency and mechanism
of action on a chemical-specific basis in
determining whether there it strong
(Category I) or limited (Category IT)
evidence of carclnogenicity. EPA
recognizes that achieving zero levels of
carcinogens in our water supplies or in
other media is not possible: MCLGs are
health goals. Consequently. EPA
believes that reducing the drinking-
water exposure to carcinogens should
lead to an overall reduction in the daily
exposures to a compound.
In conclusion, when current scientific
data do not nhow a safe threshold, it
remains Agency policy that a zero
MCLG for known or probable human
carcinogens best reflects the statutory
directive to establish a level at which no
known or anticipated adverse effects on
health occurs. At the same" time, we are
mindful that significant advances are
being made in scientific knowledge and
technology that allow us to know morf
about the process of carcinogenicity and
TABLE 15.—RELATIVE SOURCE CONTRIBUTION
to detect contaminants at increasingly
lower levels. We are continuing to
evaluate these advances to determine
whether it is possible to define levels
that have little or no meaning in terms of
cancer risk. If so. the Agency may
determine that the SDWA directive of
"no adverse effects" could be met by
other than zero MCLGs.
3. Relative Source Contribution
Table 15 summarizes the approach
EPA uses to estimate the relative
contribution from other sources of
exposure, including air and food for the
purpose of calculating the MCLG for
non-carcinogens. EPA requested
comments on this approach.
Drinking w«t»r iwposum b«tw»en 20 Drinking w«tar txpotun b«tw««n 80 Drinking „,&, uposura teas th«n 20%
•iid 80% •no 100% ^
Adequate data «r» avariabto EPA us«* actual data EPA USM an 80% (Sinking water coo- EPA usee t 20% drinkjng water contri-
tribubon. button.
Adequa* data tn not available EPA "*•» • x* <**&* water contribution.
Five commenters fully supported
EPA'» proposed approach for.developing
and using relative source contribution
(RSC) factors. One of these commenters
agreed that volatilization data are
currently inadequate for use in
establishing RSCs. Another commenter
believed sufficient data and modeling
techniques for volatilization have been
published and that human .exposure
from volatilization of drinking water
could range from 3 to 10 times that from
ingestion. Another commenter believed
current information indicates that the
vast majority of human exposure to
drinking water contaminants occurs
from ingestion; therefore, EPA should
not consider volatilization in developing
RSC factors. One commenter noted that
the majority of contaminants volatilized
from drinking water would not be
inhaled. One commenter stated that
EPA should refine its models on skin
contact and inhalation using t workshop
format, present the models to the
Science Advisory Board, and publish the
models for public comment. Many
divergent comments were received on
the use of a 20 percent floor and 80
percent ceiling (see Comment/Response
Document for details). Several
commenters objected to using a 20
percent floor and 80 percent ceiling for
the RSC when actual data are available.
One commenter asked EPA to clarify
Lhat the 20 percent floor accounts for all
routes of exposure to drinking water
contaminants (i.e., inhalation, dermal
absorption, and ingestion).
EPA Response: EPA has not
completed the modeling effort for
estimating drinking water exposure from
volatilization and dermal absorption.
The draft document "Guidelines for
Incorporation of Inhalation and Dermal
Exposures from Drinking Water in the
Calculation of Health Advisory and
DWEL Values" (U.S. EPA, 1989. draft) is
undergoing internal Agency review.
After completion of Agency review, the
document will be available for Science
Advisory Board and external review. In
the meantime, EPA maintains the
position that exposure to drinking water
contaminants from volatilization and
dermal absorption is generally limited
and adequately accounted for in the
selection of relative source contribution
factors. EPA believes that the 20 percent
floor is very protective and represents a
level below which additional
incremental protection is negligible. In
addition, below 20 percent RSC from
water is a clear indication that control
of other more contaminated media will
have a significantly greater reduction in
exposure. EPA believes the 80 percent
ceiling is required because, even if
nearly all exposure is currently via
drinking water, some portion, albeit
small, of the adjusted daily intake (ADI)
should be reserved to protect
populations with unusual exposures and
future changes in the distribution of the
contaminant in the environment. EPA
does not rely on the limits when
adequate exposure data exist between
20 and 80 percent, but when data are not
adequate, the 20 percent floor and 80
percent ceiling are prudent and
protective of public health.
4. Inorganic MCLGs
a. Asbestos. EPA proposed an MCLG
of 7 million fibers/liter (rounded off
from 7.1 million) for asbestos fibers
exceeding 10 micrometers in length
since sufficient health and occurrence
data exist to justify a national regulation
and the 1986 SDWA Amendments
require the Agency to regulate this
contaminant. EPA's proposal of 7 million
fibers/liter (for fibers greater than 10
micrometers in length) is based upon
evidence of benign polyps occurring in
male rats following the oral
administration of intermediate (>10
micrometer range) size chryso'ile fibers.
Public Comments. A total of 19
individuals or organizations provided
comments in response to the MCLG
proposal regarding asbestos. A number
of commenters (13) stated that, while
recognizing the health hazards
associated with inhalation exposure, it
was not appropriate to develop an
MCLG for asbestos due to the
inadequacy of data establishing health
risks via ingestion of asbestos. Four
commenters stated that asbestos should
not be considered as having "limited"
evidence of carcinogenicity (Group C).
but instead should be placed in "Group
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3536
Federal Regular / VoL 56. No. 20 / Wednesday. January 30. 1991 / Rules and Reg£atJooa
O" with the MCLG bated on the No-
Observed Adverse-Effect Level
(NOAEL) or Lowest-Observed-Adverse-
Effect Level (LOAEL) for ingested
asbestos. One commenter recommended
developing a health advisory cased on
available data instead of proposing an
MCLG for asbestos. Another commenter
objected to asbestos carcinogenic
classification (limited evidence. Group
C) in view of the EPA'i classification of
inhaled asbestos as Group A (known
human carcinogen) and recommended
an MCLG of zero.
EPA Response. EPA recognizes that
the evidence for the health effect* of
ingested asbestos hag limitations.
However. EPA believe* that there is a
sufficient basis to justify regulating
asbestos for the reasons outlined in the
November 13.1985. notice. Furthermore.
the 1988 SDWA amendments direct EPA
to regulate asbestos. The reasons
outlined hi the aforementioned
November 13. r98S, notice are
summarixed below:
• Asbestos has been shown to be a
human carcinogen through inhalation
exposure and is classified by EPA gs
Group A (human carcinogen).
• The results of the National
Toxicology Program (NTP) bioassay
showed an association between the
ingestion of asbestos fibers 65 percent of
which were greater then 1 micrometers
in length and benign gastrointestinal
tumors (adenomatous polyps) in male
rats. A parallel NTP study of fibers. 98
percent of which were <10, did not
produce • response In male or female
rets.
• Although these result* were not
statistically significant compared with
the concurrent controls, the incidence of
the neoplajm* was highly significant
when compared witii the incidence of
epithelial neoplasm* (benign and
malignant combined) of the large
Intestine of the pooled control groups of
all the NTP oral asbe*to« lifetime:
studies.
• The EPA Science Advisory Board
(SAB) stated that "given the positive
signal seen in some epidemiologic
studies, plu* well-documented evidence
for the association between asbestos
fiber inhalation and lung cancer, it ie
hard for the Committee to feel
comfortable in dismissing the possibility
of an increased risk of gastrointestinal
cancer in human* exposed to asbestos
fibers from drinking water."
• EPA beheves the above inform* toon
substantiate* the health significance of
asbeitoc fiber* associated with both -
inhalation and ingestion. as routes of
exposure. Therefore, (hi* evaluation of
th* h^s'th tlpniBcancc of whs&loa fibers
in drinking water is not inconsistent
with the proposed MCLG for asbestos.
In addition. The National Research
Council (NRG 1964. Nonoccupational
Health Risk of Asbe»tiform Fibers)
concluded "the association of asbestos
with an increased risk of malignancies
other than lung cancer and
mesothelioma has not been confirmed in
animal studies and has not been
observed consistently in human
studies,"
hi setting an MCLG for asbestos in
drinking water, EPA believes) the
limitations of the available dose-
response data from dietary ingestion of
asbestos justifies treating asbestos as a
Category Q contaminant EPA is
promulgating an MCLG of 7 million
fibers/liter (>10 micrometer in length)
for asbestos following review of public
comments.
b. Cadmium. In the 1989 proposal (54
FR 22082). EPA reproposed an MCLG oil
8.005 mg/1 for cadmium. T'lis value was
based upon a DWEL of 0.018 mg/L using
human renal dysfunction as an endpoint
Public Comment Comments on the
proposal were received arguing that (a)
the current interim 0.01 mg/1 standard
should be retained or possibly'
increased, (b] cadmium in drinking
water should be regulated as a
carcinogen and thus the MCLG should
be set at zero, or (c) cadmium produces
learning disabilities, birth defects, and
heart disease and thus the MCLG should
be set at zero.
Those who supported retaining the
current interim 0.01 mg/1 standard or a
higher varae b«*ed their argument on a .
variety of points, trtcrading the
following: (s) The interim 0.01 mg/1
standard is safe, and/or (b) the current
0.01 mg/1 standard w supported by the
conclusion of the World Health
Organization (WHO) that the
provisional tolerable weekly intake for
cadmium should be established at a
level no< to exceed 0.4-0.5 mg/perton.
Those who argued that cadmium in
drinkk^ water should be regulated as *
Group I carcinogen (i-e.. set the MCLG at
zero). coUectrvely, provided an
extensive analysis of the oncogenic
potential of cadmium via nco-iogestfoa
routes of exposure in agreement with
EPA's OWE analysis.
An additional comments argued that
the standard should be zero, a*
cadmium produces learning disabilities,
birth defect*, and heart dfaJMse, bet th«
commenter prcrnoWd no data adequate
to conclude that the proposed standard
would not protect agcdnst soon adverse •
effect* ihould they occur.
EPA Response. While a level of OJJ1
mg/1 k> probably without affect in .most
faidJviduak, EPA is no* convinced th*>t a
level of 0.01 mg/1 or higher contains at*.
adequate margin of safety to protect
sensitive subpopulations as required by
the SDWA. As noted in the 1989
proposal, WHO recommends 0.005 mg
cadmium/1 of drinking water, a value
identical to the proposed MCLG: the 0.4-
0.5 mg/person value cited in the
comments principally concerns the diet
which, in EPA's opinion, is not relevant
to a drinking water standard.
As stated in the 1989 proposal. EPA
classified cadmium in Group Bl,
probable human carcinogen, based upon
animal end human evidence of long
cancer from inhalation exposure.
Chronic oral animal studies with
cadmium have shown kidney damage •
but no carcinogenic activity and
ingestion-BpeciSc human data are not
available. Therefore, in setting an MCLG
for cadmium in drinking water, EPA
believes the lack of cancer dose-
response evidence from ingestion of
cadmium justifies considering cadmium
as a Category HI contaminant Those
comments that conclude that cadmium
is a carcinogen provide no new evidence
that cadmium is carcinogenic via
drinking water but rather, argue that it is
prudent to assume that cadmium is
carcinogenic via ingestion. As drinking
water studies in rats of two cadmium
salts have not shown a dose-response
basis for risk {e.g.. ATSDR. 18SS), EPA
believes that for drinking water
purposes cadbsiiuai should be a Category
HI coQtasifeant (dsronJc toxidty but
lackiag evkkssoe of carcinogenicity).
The coi9si«titer arguing that cadmium
produces learning disabilities, birth
defects, asd heart die&aee provides no
conviscJag evidsrscs that the proposed
standard would not protect egainst such
effects should &ey occur at higher levels
of exposare. EPA dfefflgr©ss that the
MCLG ehotuld b* set at sero on this
basis.
After reviewing tba public comments,
EPA hsa caocludeil that cadmium
should be placed In Category ID and
that an MCLG of 0,005 mg/l foe
cadmium, as proposed, bated on the
meat sensitive eadpoint is appropriate.
c. Chromiuta. In tiss 1233 proposal (54
FR 22062), EPA repropoaed an MCLG of
0.1 mg/1 for total chromium (chromium
m and VI).
Public Comment. Comments were
received that recommended that (a) the
0.1 mg/1 vmlue txs adopted, (b) separate
aiandards be adopted for O VI ajsd Cr
m as there is no evidence that Cr m u
oxidised to Cr VI in drinking water, and
(.c) chromium be considered potentially
carcinogEffik: to humans via the oral
route; Jius, EPA shoiild promulgate en
MCLG of fcevo Jo? ehrornmra.
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Federal Register / Vol. 56. No. 20 / Wednesday, January 30, 1991 / Rules and Regulations 3537
EPA Response: The 1M9 proposal
stated that "EP.-Vs Office of Resear;h
and Development has shown Cr III to
oxidize to Cr VI in the presence of an
ox-.dant such as chlori.ne at
cor.centri'.:ons similar to those used to
J. r.nfect cnnk;ng water." EPA
rr ..r.'.air.s tr.is view despite seme public
c :r.rr.er.ters who state '.hat there is no
i.: ,.J.ence that Cr lii :s o«.:d:zed to Cr VI.
Those 'jciv.rr.cr.t-ers who argued- ;hit
chromium is carcinogenic, in part.
svppcrt EPA's conclusion that Cr VI is
carcinogenic follcv/ing exposure by
inhalation. From a hazard identification
•perspective. EPA has classified Cr VI in
Group A, i.e.. a huir.an carcinogen via
inhalation, and considers Cr VI to have
various genotoxic characteristics
including being a rautagrn and
clastoaen. Ln comparison, the evidence
for Cr III is largely non-positive or
..q-ivccal and is v.ewecl as inadequate
'o develop more clear conclusions.
Notably Cr III in trace amounts is an
essential nutrient Tor the metabolism of
carbohydrates.
Specific dose-response evidence for
Cr VI carcirogenicity by oral exposure
is not available at this juncture.
Commer.ters did not present any new
information on this point. In comparison.
^e-body of dcse-response evidence for
inhalation exposure is relatively large
ar.d consists mainly of human data. The
data base comes from epidemiologic
studies of chromate and ferrochromium
production workers, chrome pigment
workers, and chrome platers where the
predominant chromium species is Cr VI.
While lunj cancer is the focus of these
studies, there is also some evidence of
dr\ increased hazard of gastrointestinal
tra^t cancer suggesting that respiratory
clearance'and swallowing or some other
physiologic distribution of a reactive
chromiiim species is taking place.
Unfortunately, most studies did not
investigate or did not detect the
presence of any clear dose-response
relationships, nor is it obvious that other
?pcc;f;c confounding factor* for the
possible gastrointestinal hazards were
accounted for.
While oxidation of Cr in to Cr VI may
occur in the water treatment system,
reduction of Cr VI to Cr III occurs in
marmnaHar.y The saliva and gastric
juice in the upper alimentary tract cf
r^amrcals. including humans, have a
varied capability to reduce Cr VI with
the gastric juice having a notably high
caoacity. To the extent that Cr VI
survives these reduction environments
c'.hc: organs/tissues such at the liver,
. red blood cells and some lung cells are
sisc reducing environment*. Thus, the
body s normal physiology provides
detoxification for Cr VI. which provides
protection from the oral toxicity of Cr
VI.
EPA recognizes that by focusing on
total chromium the issues of chromium
species-specific toxicity. e.g.,
carcinogenicity. become mixed.-We rote
that Cr III and Cr VI chemistry is
already intertwined in the water
treatment process since the two valence
states of chromium are in a dynamic
equilibrium with the d?gree of oxidation
depending on such factors aspH,
dissolved oxygen, or the presence of
reducing agents. Other equilibriums
exist in the ma^mali.in system and thus
a clear separation of Cr III end Cr VI is
net feasible at this time.
The lack of available Cr VI dose-
response information for oral exposure
precludes an estimation of the possible
magrJ'.ude of cancer risk, if any, from
drinking water exposure. The available
information shows that the capacity for
reduction of Cr VI to Cr III can be quite
high relative to expected drinking water
levels of total chromium. There is.
however, insufficient information to
describe the rates of reduction and the
temporal fate of free or biologically
available Cr VI. Since Cr VI is
preferentially absorbed compared to Cr
III, the amount of biologically available
Cr VI is uncertain.
EPA concludes that the presence of Cr
VI in drinking water should be
minimized in recognition of its biological
reactivity including its potential for a
carcinogenic hazard. Such minimization
will limit the likelihood of saturating the
normal reduction/detoxification
mechanisms in humans and likewise
limit the systemic absorption of any
residual Cr VI. Without the necessary
information to further evaluate the
possibility of carcinogenic risk. EPA
believes that .'rinking water exposure
limitations for total chromium based
upon other, i.e., non-carcinogenic, health
endpoints is the only feasible approach
to follow at this time.
The MCLC for total chromium is
devsloped fr"i- health effects data for
Cr VI,-the mo:<» toxic chromium species,
and is based on EPA's RfD methodology
(see 1989 proposal). Since the MCLG
includes both Cr IH and Cr VI. no
category has been assigned for total
chromium due to some of the issues
discussed earlier. Should new
information become available which
adequately demonstrates the cancer risk
from ingestion of Cr VI. the MCLG for
total chromium would be reexamined,
especially since Cr VI levels can
predominate from spills, uncontrolled
waste sites, or geologic formations of Cr
VI makeup. Therefore, EPA is
promulgating an MCLG of 0.1 mg/l (100
Hg/1). as proposed in 1989. and further
recommends that the ji uncertainty
regarding Cr VI carcinogenic risk
warrants additional investigation.
The MGLG level also falls into the
estimated safe and n adequate daily
dietary intake range cf 50 to 200 tig/day
for Cr III established by the National
Research Council in the National
Academy of Sciences (NAS. 1939). The
lower limit is based on the absence of
deficiency symptoms in individuals
consuming an average of 50 jig/day '
chromium. The upper limit was
identified from several studies where no
adverse effec1 ~ were noted in
individuals consuming 200 fig/day
chromium. Consequently, for the
reasons stated above. EPA promulgates
an MCLG cf O.I mg/l. as proposed.
d. Mercury. EPA proposed an MCLG
of 0.002 mg/l for mercurv in the May 22,
1989 proposal. The MCLC v. as derived
from a DWEL of 0.01 mg/l applying a 20
percent contribution from drinking
water. The EPA held a workshop on
issues regarding the DWEL for mercury
(EPA. Peer Review Workshop on
Mercury Issues. Summary Report.
October 28-27,1987). The workshop
considered three major studies (Druet et
al.. 1973: Andres P.. 1984: Bemaudin et
al.. 1981) using the same
endpoints(kidney damage) for mercury
toxicity. The workshop concluded that
0.01 mg/l was an appropriate level for
the DWEL.
Public Comments: EPA addressed the
public comments received in response to
the previous proposal "of November 13,
1985 in the Federal Register Notice of
May 22,1989. In response to the Federal
Register Notice of 1989, one commenter
questioned the use of the studies by EPA
for the calculation of DWEL and
recommended the use of the Fitzhugh ct
al. (1950) study inatead. The Fitzhugh
study noted damage to the kidneys as
did the studies selected by" EPA. The
NOAEL from the Fitzhugh study was
0.315 mg/kg as compared :o the LOAEL
of 0.32 mg/kg from which EPA dsrived
the DWEL.
EPA P.esponse: EPA examined the
Fitzhugh study and found it
inappropriate for DWEL determination
because of the lack of reporting on
which adverse health effects were
observed in each dosing group.
Consequently. EPA will continue to base
its MCLG on the three studies
previously cited. Thus. EPA has placed
mercury in Category HI and promulgates
an MCLG of 0.002 mg/l in drinking
water.
e. Nitrate/Nitrite. In the 1389 proposal
(54 FR 22062), EPA proposed MCLGs of
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3538 Federal Register / Vol. 56. No. 20 / Wednesday. 'January 30. 1991 / Rule3 and Regulations
10 mg/1 (as N) for nitrate and 1 mg/1 (as
NJ for nitrite, and. in addition, proposed
that the sum of nitrate and nitrite shall
not exceed 10 mg/1 (as N). EPA based
the MCLGs on the tox;city of nitrate-in
humans due to the reduction of nitrate to
nitrite in the human body. By reacting
with hemoglobin, nitrite forms
methemoglobm (met Hb). which will not
transport oxygen to the tissues and thus
can lead to asphyxia (i.e.. blue babies)
wh:ch. if sufficiently sevcie. can lead to
death. The current standard for r.itrate.
which was promulgated in 1975. was
based on the previous Public Health
Standard which, in turn, was based on a
hterature survey [Walton. G. 1951.
"Survey of Literature Relating to Infant
Methemoglobinemia Due to Nitrate
Contaminated Water." Am, /, Pub.
Health 41:986-996).
The proposed standard is somewhat
more stringent than the current MCL of
10 mg/1 because it includes an MCL for
nitrite (the more toxic form) and a joint
standard of 10 mg/1 for nitrate and
mtn'.J. Since both nitrate and nitrite
result in met Hb, toxicity of nitrate and
nitrite may be additive. EPA proposed
the joint nitrate/nitrite standard in order
to account for the possible additive
toxicity of these two chemicals and also
to protect against the deterioration of
drinking water quality, since the
presence of nitrite in water is indicative
of water contaminated with sewage.
In the proposal, EPA specifically
requested comments on the following
issues: (1) The potential cancer risk
through drinking water exposure. (2)
potential developmental effects and
whether the proposed MCLG provides
adequate protection against such effects,
and (3) whether a lower MCLG would
be more appropriate.
(1) Nitrate and Cancer
One coramenter stated that there is no
definitive evidence from animal
b:oassay studies that nitrate itself
causes excess tumors and.,further, t"he
various eptdemiological studies that link
nstrate and/or nitrite to cancer are'not
conclusive Another commenter argued
tnat (a) the Gilli et al. (1934)
eoidemiology study [Gilli et al..
Concentrations of Nitrates in Drinking
Water and Incidence of Gastric
Carcinomas: First Descriptive Study of
!ne Piemonte Region. Italy. Science of
the Total Env.. V. 34, pp. 35-ta. 1984]
provides evidence that nitrate in
drtnk.ng water is oncogeruc (i.e..
increased incidence of gastric
carcinomas) and (b) Forman et al. (1985)
and Al-Dabbagh et al. (1986) are
.ra-equate to conc.ude whether nitrate
&id nitrite are carcinogenic. [Both
Fonr.an et a!, (1985) and AJ-Dabbagh et
al. (1986) were discussed in the 1989
proposal (54 FR 22062).] Another
commenter noted that the 1989»proposal
referenced a number of epidemiologic
studies (e.g., Burch et al., 1987) that
show an association between cancer
and nitrate. Finally, another commenter
stated that several epidemiologic studies
show an association between preformed
N-mtroso compounds and cancer.
EPA Response. EPA has reviewed the
data submitted by the public as well as
significant other data (see Drinking
Water Criteria Document for Nitrate and
Nitrite. 1990). At this time, EPA is not
convinced that mtrate and/or nitrite in
drinking water presents a potential risk
of cancer. EPA docjs not believe that
data concern.ng the possible
oncogenicity of nitrate and/or nitrite
can be entirely dismissed, however.
In attempting to resolve this issue, it is
. desirable to directly seek the assistance
of other Federal agencies concerned
with other sources of nitrat;. Thus. EPA
intends to form an inter-agency work
group to determine what, if any,
or.cogenic risks exist.
(2) Other Effects
Prior to the May 1989 proposal, the
Agency reviewed the possible health
effects associated with nitrate and
nitrite. EPA concluded that (a) infants
are the most sensitive subpopulation. (b)
methemoglobinemia is the most
sensitive toxic endpoint in infants, and,
(c) a level of 10 mg of nitrate and.
separately, a level of 1 mg of nitrite
(both as N) will protect infants
(Note: the calculated RfD is based on this
conclusion).
Since the 1989 proposal, the Agency
has reexamined the RfD for nitrate
considering new data. This review
reaffirmed the original conclusion that
10 mg nitrate per liter would protect
infants.
Li reaching this conclusion the
Agency examined a large number of
papers concerning the toxicity of nitrate
and nitrite. These papers separately
dealt with chronic toxicity.
developmental and reproductive
toxicity, and methemoglobinemia
(among other endpoints). Data
concerning both humans and
experimental animals were reviewed.
EPA has reviewed the data on
developmental and reproductive
toxicity. Based on that review, EPA
believes the data are inadequate to
conclude that nitrate and nitrite present
a nsk of developmental or reproductive
effects at the MCLGs.
In addition, the Agency reviewed all
public comments as well. The issues
raised by the public are substantially
similar to those examined by EPA.
Based on a review of the data, EPA
has concluded that an MCLG of 10 and 1
mg/1. respectively, are adequate to
protect infants, and all other groups.
against the nononcogenic effects
presented by nitrate and nitrite in
drinking water.
(3) C;her Issues
Other commenters recommended that
EPA (a) adopt the MCLGs proposed in
1989 for nitrate and nitrite bat not adopt
the proposed MCLG for the sum of
nurate and nitrite, as it is unnecessary:
(b] adopt the MCLGs proposed in 1989
for nitrate and the sum of nitrate and
nitrite but not adopt the MCLG proposed
for nitrite, as it Is unnecessary; (c) only
adopt the MCLG proposed for nitrate, as
the other two MCLGs are i.nnecessary:
and (d) adopt the proposed MCLGs for
nitrate and nitrite but increase the
proposed MCLG for the sum of nitrate
and nitrite from 10 mg/1 to 11 .T.g/l (both
as N).
EPA disagrees with recommendations
(a) through (d). above, for the following
reasons:
• It is clear that nitrite may occur in
drinking water and also that nitrite is
toxic, thus a nitrite standard is needed.
• As nitrate is toxic because it is
metabolized in the human body to
nitrite, it is reasonable to conclude that
the toxicity of nitrate and nitnte is
additive. Thus, in agreement with the
recommendations of the SAB. a
combined standard for nitrite and
nitrate is warranted.
• Adoption of an 11 mg/1 (as N)
combined standard for the sum of
nitrate and nitrite, in effect, would mean
that a combined standard was
unnecessary. For the reasons previously
stated. EPA disagrees.
Based on the previous discussion.
EPA has placed nitrate and nitrite in
Category III and promulgates the
MCLGs for nitrate, nitrite, and the sum
of nitrate and nitrite at 10 mg/1.1 mg/1,
and 10 mg/1 (as N). respectively.
/. Selenium. In the 1989 reproposa'. (54
FR 22062), EPA proposed an MCLG of
0.05 mg/1 for selenium and specifically
requested comment as to whether an
MCLG of 0.02 or 0.1 mg/1 might not be
more appropriate.. The basis of the
'current proposal is discussed below.
Public Comment. EPA previously
addressed the public comments received
in response to the previous proposal of
November 13,1985 in the Federal
Register Notice of May 22.1989.
(A) The majority of commenters •
supported an MCLG of 0.1 mg/L With
one exception, no significant additional
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Federal Register / Vol. 56, No. 20 / Wednesday. January 30. 1991 / Rules and Regulations 3539
data were provided. However, one
commenter recommended that, bated on
a 1989 study by Yang et at. [Yang et al..
Studies of Safe Maximal Daily Dietary
Se-In'.ake in a Seleniferous Area in
China. J. Trace Elem. Electrolytes Health
Dis.. part 111. Vol. 3. pp. 123-130,1989).
EPA should consider a lower MCLG
value. In addition, the same commenter
observed that e number of individuals
take selenium supplements (i.e..
selenium is an essential trace element)
and thus exposure may be significantly
greater than EPA anticipates.
EPA Response. The 0.05 mg/1 value
proposed in 1888 is based on a human
effect level observed by the same author
{Yang et al.. 1983). EPA normally prefers
to base MCLGs on no-effect levels,
which are more conservative than
human effect levels. However, at the
time of the 1939 proposal, an
appropriate no-effect level was not
available. However, Yang et al. (1986)
provides a no-effect level obtained from
a human study in China and suggests
that 0.400 mg of selenium/person/day is
a maximal daily safe intake of selenium.
Assuming the consumption of 2 liters
of water/adult/day, consumption of
water containing selenium at the
proposed 0.05 mg/1 MCLG would result
in the ingestion of 0.1 tag selenium/
person/day. As previously stated (54 FR
22062), the average daily dietary intake
in this country is 0.125 mg selenium /
person/day. Thus, the combined
ingestion of water containing 0.05 mg/1
and a typical U.S. diet would result in a
total daily exposure of 0.225 mg
selenium/person, a value well below the
0.400 mg selenium that Yang et al.
suggests is safe. Consequently, EPA hr 3
concluded that Yang et at (1989) •
supports the proposed MCLG of 0.05
mg/1.
EPA believes that the difference (i.e.,
0.175 mg selenium/person/day) between
dietary intake (0.225 mg selenium/
person/day) and the maximal daily safe
intake of selenium (0.4 mg selenium/
person/day) recommended by Yang et
-al. (1989) is adequate to protect those
who may take selenium supplements.
Thus, EPA believw that mt 0.05 mg/1
value is adequate to protect both the
general public and those who may take
selenium supplements.
(B) Although providing no new data,
other commenters recommended an
MCLG of 0.1 mg/1 or higher.
EPA Response. EPA disagrees with
these comments for the following
reasons: (1) It is likely that there are
.iidividuals who. whether due to diet or
.uppleraect* consume significantly
more selenium than the 0.125 mg
selenium/person/day that EPA has
estimated that the average citizen
consumes, and (2) EPA .believes that an
MCLG higher than 0.05 mg/1 may not
adequately protect those who
chronically consume such elevated
amounts of selenium. Thus. EPA has
rejected those comments that argue for
en MCLG of 0.1 mg/lor more. .
After reviewing the public comments,
EPA has concluded that selenium should
be placed in Category IH and an MCLG
of 0.05 mg/1 is promulgated.
5. Volatile Organic Contaminants
(VOCs) MCLGs
a. cis-1.2-Dichloroethylene and trans-
1.2-Dichloroethvleno. EPA proposed an
MCLG of 0.07 mg/1 based on a 3-month
study in rats using tis-1.2-
dichloroethylene. From that utidy, a
DWEL of 0.4 mg/1 (rounded from J 45
mg/1) was calculated and • 20 pen.ent
drinking water contribution wan
assumed. For trans-l,2-dichloroethylene.
EPA proposed an MCLG of OJ mg/1
based on compound-specific data. A
DWEL of 0.6 mg/1 w^s derived and a
drinking water contribution of iO
percent was assumed to determine the
MCLG.
Public Comments and EPA Response.
EPA previously addressed the public
comments received in response to the
earlier proposal of November 13,1985 in
the Federal Register Notice of May 22,
1989. With respect to the cii isomer, one
commenter stated that data on 1,1-
dichloroethylene should not be used for
the cis compound, because there is no
evidence that the effects of the two
compounds are similar. Another
commenter stated that the MCLG for
cis-1.2-dichloroethylene should be based
on Freundt and Machol* (Toxicology
10:131-139,1978). Another commenter
stated that the NTP two-year bioassay
for 1,1-dichloroethylene was a better
study for deriving a NOAEL/LOAEL for
determinirg MCLGs/MCLs.
For the trans isomer, one commenter
stated that their MCL was lower than
EPA's MCL. However, they need to
review the Barnes et aL (Drug Chem.
Toxicol. 8.373-392,1985) manuscript
prior to revising their MCL.
Another commenter disagreed with
the selection of NOAEL/LOAEL from
the Barnes et aL study and stated that.
based on the increase in glucose levels
and decrease in aniline hydroxylase
activity, 17 mg/kg/day should be a
LOAEL and not a NOAEL..
The final MCLG for tis-1,2-
dichloroemylene is based on a 3-month
compound-specific study by McCauley
et al. The Agency's RfD Workgroup has
reviewed the data and verified a RfD of
0.01 mg/kg/day.
Then; are several reasons that the
Agency is not u§ing the Freundt and
Macholz (1978) study to set an MCLG.
First, it is a single eight-hour exposure.
EPA does not generally use single
exposure studies to set lifetime
numbers. Second, it is an inhalation
exposure and the Agency prefers to use
route-specific (oral) data if possible.
Third, the selection of an adverse effect
in the Freundt and Macholz (1978) study
is questionable. A decrease in
micrbsomal metabolism (i.e., aniline
hydroxylase), while an obvious effect, ia
not necessarily an adverse effect. In
fact if a chemical is activated to a toxic
metabolite, inhibition of that chemical's
metabolism.might be beneficial. Fourth,
and most important the Agency
presently has an oral three-month study <
on cis-1.2-dichloroethylene.
The Agency did not select the NTP
two-year bioassay because they gave
the 1,1-dichloroethylene in com oil and
oil vehicles have been reported to
potentiate the adverse effects of 1,1-
dichloroethylene (Chieco et al., Toxicol.
Appl. Pharmacol. 57:146-155.1981).
Since the new trans-1.2-
dichloroethylene data are going to be
reviewed by the commenter, no Agency
reply is necessary at this time. With
respect to selection of a NO1 AEL/LOAEL
in the Barnes et al. (1985) study, the RfD
workgroup did review the data very
carefully. Tables 11 and 12 of the Barnes
et al. (1985) paper do report that there
ars significant increases in serum
glucose levels in both male and female
CD-I mice. However, even though the
difference between the low- and high-
dose levels administered to the mice is
20 fold, there are no differences in serum
glucose levels at these two doses. This
calls into question the lexicological
significance of the increased glucose
levels. In addition, the Agency does not
know the normil range for variation in
serum glucose for this strain. The
Agency's RfD workgroup did not believe
that either the increased serum glucose
levels or the decreased aniline
hydroxylase levels (also sc« discussion
for cis-1.2-dichloroethylene) were
adverse effects. Accordingly, the 17 mg/
kg/day treatment level wao used as a
NOAEL. EPA has placed cis-1,2-
dichloroetbylene and trans-1,2-
dichloroethylene in Category in and the
respective MCLGs of 0.07 and 0.1 mg/1
will be retained.
b. 1.2-Dichlorcpropcne. EPA proposed
an MCLG of zero for 1.2-
dichloropropane based on the
statistically significant increased
incidence of hepatocellular neoplasms
and primary adenomas in male and
female B6C3F t mice. The frequency of
liver carcinomas alone wan not
significant for males or females, but
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Federal Register / Vol. 56. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations
(here was an increase in tumors in both
sexes. Also, there was a dose-related
trend in mammary adenocarcinomas in
female F344 rats. The increased
adenocarcmoma incidence in the female
rats was considered to be significant
s:nce the F344 rat has a relatively low
background occurrer.ee ra'e for these_
tumors. Therefore. EPA c!ass;::ed 12-"
dichloropropane in Group B2.
Pub.'.c Corr.mer.Zs. Three :r.div:d_ai3
or organizations provided comments m
response to the MCLG proposal
regarding 1.2-dichloropropane. One •
commenter was in agreement with
FPA's proposed classification of 1.2-
dichloropropane into Group B2. and
with EPA's proposed establishment of
an MCLG at zero. Two commenters
stated that a problem might exist with
;he NTP study of B6C3F \ mice in terms
of showing a high incidence of tumors in
the control mice compared to the mice
which received the high dose of this
chemical. They suggest a revaluation of
tnis study before establishing an MCLG.
EPA Response. The EPA's
classification of 1.2-dichloropropane in
Group B2 was based on the results of
the final NTP report. This report was
peer reviewed and audited by the Peer
Review Panel and Audit Workgroup.
respectively, and was found acceptable
in terms of results reported in the final
NTP report. EPA concludes that a
reevaluation of this study would not
change the findings of this report.
Consequently. EPA has placed 1,2-
dichlcropropane in Category I and an
MCLG of zero is promulgated.
c, Ethylbenzene. EPA proposed an
MCLG of 0.7 mg/1 ."or ethylbenzene. The
MCLG was denved from a DWEL of 3.4
rr.g/1. by applying a 20 percent drinking
water contribution and rounding off to
one significant number.
Public Comments. EPA previously
addressed the public comments received
in response lo the earlier proposal of
November 13.1985 in the Federal
Register Notice of May 22. 1989. In
response to the 1989 Federal Register
No'.ice. one commenter agreed with the
choice Df study. NOAEL and LOAEL
but questioned the use of a 10-fold
uncertainty factor to convert from
subchronic to chronic exposure. The
commenter explained this position in the
following manner: Since the adverse
pffec's =f djses 3- or 5-foiJ h:gher than
the NOAEL were minor and a 2-year
NTP study on mixed xylenes. which
contained 17 percent ethyibenzene
t'O'jivalent to 83 mg of ethylbenzene/
f i say I. sno'ved no adverse effects, the
ev.ra 10-foid uncertainty factor could be
omitted,
ETA Response EPA believes that thl-
:>:i>.d uncertainty factor for converting
a subchronic to a chronic study is still
necessary for several reasons. In the
Wolf et al. study (Arch. Ind. Hlth 14:387-
398. 1956), the NOAEL of 136 mg/kg was
adjusted by 5/7 since the animals were
treated for only 5 days/week. Some
recovery from the effects of
ethylbenzene could have occurred
during the two days of non-treatment.
The administration of 85 mg of ethi-1-
benzene/kg/day as part of an assay of
mixed xylenes does not necessarily
mean that a 85 mg ethylbenzene/kg/day
dose is without effect since EPA does
not know about potential interactions
among the compounds. In addition, the
finding of minor adverse effects at doses
3- and 5-fold higher than the NOAEL
does not exclude the possibility that
extended exposure at lower doses
would lead to adverse effects. Since
there are many unanswered questions
on the toxicity of ethylbenzene. EPA
feels that the 1.000-fold uncertainty
factor, including a 10-fold for subchronic
to chronic exposure, is appropriate for
this chemical. Consequently. EPA places
ethylbenzene in Category III and the
MCLG of 0.7 mg/1 is promulgated as
proposed.
d. Monochlorobenzene. EPA proposed
an MCLG of 0.1 mg/1 for
monochlorobenzene in the May 22.1989
proposal. The MCLG was derived from a
DWEL of 0.7 mg/1. applying a 20 percent
contribution from drinking water and.
because of reclassification of
monochlorobenzene in Group D
(ii.adequate evidence for
carcinogeniciry,1 according to the EPA
guidelines, no additional uncertainty
factor for possible carcinogenicity. This
MCLG is a revision of the MCLG of 0.06"
mg/1 (derived from a DWEL of 3.0 mg/1,
applying a 20 percent contribution factor
from drinking water and an uncertainty
factor of 10 used with agents classified
in Group C (possible human carcinogen:
for monochlorobenzene, limited
evidence in animals based on increased
neoplastic nodules in liver of male rats
in one bioassay)) previously proposed in
November 13,1985. Revision of the
MCLG to change tha basis for the DWEL
and downgrade the carcinogenicity
classification from Group C to Group D
(Category II to III) is the result of further
review of data and review of the MCLG
for monochlorobenzene by the EPA's
Science Advisory Board in 1988.
Public Comments. EPA addressed the
public comments received in response to
the previous proposal of November 13,
1985 in the Federal Register Notice of
May 22. 1989. Two ccmmenters
responded to that Federal Register
notice. The first commenter supported
reclassification of monochlorobenzene
from Group C to Group D. The second
commenter felt that the appropriate
classification is Group C and that an
additional uncertainty factor should be""-
applied to the study used to derive tha
DWEL to account for limitations in
study design.
EPA Response. EPA agrees with the
commenter who supports
reclassification of monochlorobeczene
from Group C to Group D. EPA
reclassified monochlorober.zer-.e after
concluding that the combination of
neoplastic nodules and hepatccellular
carcinomas in male rats in the
carcinogenicity bioassay was not
adequate evidence of a treatment-
related effect to, in turn, support limited
evidence for carcinogenicity of
monochlorobenzene in animals. EPA
disagrees with the second commenter
that an extra uncertainty factor is
needed with the study used as the basis
for the DWEL because EPA considers
the 1.000-fold uncertainty factor already
used with the study as adequate
compensation for uncertainty
surrounding limitations in the study
design. Consequently, as discussed
above, EPA places monochlorobenzene
in Category III and an MCLG of 0.1 mg/1
is promulgated.
e. ortho-Dichlorobenzene. EPA
proposed an MCLG of 0.8 mg/1 for
ortho-dichlorobenzene in the May 22,
1989 proposal. The MCLG was derived
from a DWEL of 3.0 mg/1, applying a 20
percent contribution from .drinking
water.
Public Comment. One commenter felt
that because a NOAEL from a chronic
(two-year) study in rats was used for
calculation of the DWEL. the
uncertainty factor should be 100 instead
of 1,000 as used by EPA.-
EPA Response. EPA disagrees with
the comment that the uncertainty factor
for the DWEL calculation should be 100.
instead of 1.000. Although EPA
cominonlyapplies a 100-fold uncertainty
factor with a chronic (lifetime) study in
rats. EPA chose to use a 1,000-fold
uncertainty factor for the DWEL
calculation for ortho-dichlorobenzne
because toxicity endpoints were
assessed in a nreliminary subchroiac
(13-week) study in rats that were not
evaluated in the chronic study and
because of data gaps (an inadequate
reproductive toxicity study in a non-
rodent species reproduction study).
Consequently, EPA places ortho-
dichlorobenzene in Category III and an
MCLG of 0.6 mg/1 is promulgated as
proposed.
/. Styrene. EPA proposed two MCLGs
in the May 22.1989 proposal because
EPA had not yet finalized its
carcinogeniciry classification for
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Federal Register / Vol. 56. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations 3541
ityrene. One MCLG of 0.1 mg/1 was
derived from a DWEL of 7 mg/1.
applying a 20 percent contribution from
drinking water and an additional 10-fold
uncertainty factor by considering the
classification of styrene to be Group C.
The other MCLG was zero, considering
the classification of styrene to be Group
B2. At meetings on styrene with EPA's
Science Advisory Board in 1988 and
1990. EPA favored a classification .of
Group B2. whereas the SAB opinion
favored a classification of Group C.
Additionally, at the 1990 meeting with
the SAB. the SAB preferred a
multigeneration reproduction/chronic
toxicity study in rats over the
Bubchronic toxicity study in dogs the
EPA had used for calculation of the
DWEL,
Public Comments. EPA addressed the
public comments received in response to
the previous proposal of November 13,
1985 in the Federal Register Notice of
May 22,1989. In response to that Federal
Register Notice, six commenten
advocated no classification for styrene
or, if it it to be classified, classification
into Group D. One of these commenten
also preferred use of the rat study over
the dog study, as described above, for
calculation of the MCLG. This
commenter felt the MCLG should
therefore be 1.6 mg/1 (which EPA would
round to 2 mg/1). calculated as a Group
D classification, thereby omitting the
extra uncertainty factor of 10 required
for styrene in Group C. Two commenten
supported classification of styrene in
Group B2 and promulgation of an MCLG
of zero, in the opinion that the data are
sufficient to meet the criteria for Group
B2. Two commenters felt the proper
classification for sryrene is Group C and
an appropriate MCLG is 0.1 mg/1.
EPA Response. The EPA has not
classified styrene e? to its
carcinogenicity potential at-this time.
The EPA has presented to the Science
Advisory Board argument* to classify
styrene in Group B2; probable human
carcinogen. The Science Advisory Board
responsed that the weight of evidence
supported a group C classification. Thus,
the cancer classification Issue is still
under review by the Agency.
Via corn oil gavage, there is some
evidence that styrene may induce
tumors in rodents, and a cancer risk of 9
x 10"' per fi.g/1 is estimated from the
NCI mouse study (NCI. 1979). Available
oral studies tn rats have not shown
carcinogenic activity. In setting an
MCLG for styrerie in drinking water,
EPA has carefully considered the overall
.weight of evidence of cancer, especially:
(1) The comparatively low estimated
cancer potency (based on the corn oil
gavage study): (2) the lack of a
carcinogenic response in an adequately
conducted drinking water study. In
addition, styrene is not likely to be
widespread in drinking water based on
occurrence information currently
available in the Agency. Consequently.
EPA is placing styrene in Category II
and is promulgating an MCLG of 0.1 ing/
1 based on the Quast et al. (1978) study
in dogs.
g. Tetrachloroethylene. In the May.
1989 notice. EPA proposed an MCLG for
tetrachloroethylene (perchloroethylene
or PCE) of zero. The Agency has found
strong evidence of carcinogenicity from
ingestion based on consideration of the
weight of evidence, phannacokinetici
find exposure.
The Agency uses a three category
approach to set MCLGs under the Safe
Drinking Water Act (see 50 FR 48944-
46949 (November 13.1985) and 54 FR
22068 (May 22.1989)). A. chemical for
which there is strong evidence of
carcinogenicity is placed in Category L
As a matter of policy, EPA sets MCLGs
for chemicals in Category I at zero (see
earlier discussion of this policy).
Recognizing the continuing scientific
controveny over the appropriate weight
of evidence for the chemical the Agency
also solicited public comment on an
MCLG of 0.01 mg/1 which would reflect
a possible human carcinogen (Category
13). EPA received a number of comments
on the proposal and these comments are
addressed below.
In separate actions, the Agency is
currently deliberating concerning an
Agency-wide classification of PCE,
according to its normal procedure. On
December [28], 1990, EPA issued e
notice for publication in the Federal
Register that described the process the
Agency is following to bring these
deliberations to a conclusion. (A Federal
Register citation for that notice was not
available on the date of signature of
today's notice; however, the title of the
• notice is "Amendment to Preambles
Published at 54 FR 33418 (August 14.
1989) and 54 FR 50968 (December 11.
1989))".
While these deliberations continue,
EPA must take final action on an MCLG
and NPDWR for tetrachloroethylene.
This chemical is included on the list of
83 chemicals that Congress specifically
directed EPA to regulate. The Agency is
under court order to promulgate
regulations for this contaminant by
December 31.1990. Accordingly. EPA
today is promulgating an MCLG for PCE
in accordance with the three-category
approach developed to implement the
SDWA. This action does not reflect a
final Agency decision on PCE's
classification: it represents a separate
and distinct regulatory evaluation and
risk management decision concerning
PCE. When the Agency completes its
deliberations regarding classification.
we may reconsider the MCLG for
tetrachloroethylene. as appropriate.
Based on EPA's careful review of the
comments received in response to the
May, 1989 notice and the Agency's
evaluation of scientific evidence
available since the proposal, it remains
EPA's view that there is strong evidence
of carcinogenicity through ingestion and
that PCE is a Category I chemical for
purposes of establishing an MCLG under
the SWDA.
Pv-'-iY- Comments. The pivotal
comm!?-- ts dealt with EPA's
categorization of tetrachloroethylene as
a probable or possible human
carcinogen for purposes of setting an
MCLG under the SDWA. One
commenter argued that: (1)
Tetrachloroethylene metabolites/
trichloroacetic acid, which are
carcinogenic, were tested in a sensitive
strain of mice having a high background
liver tumor incidence. (2) mononuclear
cell leukemia observed in animals may
not be relevant to man, and (3) renal
tumors observed in male F-344 rats are
species-specific. One commenter argued
that this contaminant is a probable
human carcinogen; another supported
classification of PCE as a posaible
human carcinogen.
EPA Response. Based on the available
carcinogenicity evidence from
experimental animal studies and the
high frequency of occurrence in drinking
water. EPA continues to view PCE as a
Category I contaminant for drinking
water regulation- Tk* evidence for
carcinogenic hazard has two parts, i.e..
epidemiologic data and animal data as
supplemented by metabolism
information and results from short-term
studies. In 1985 EPA viewed the
epidemiologic data as inadequate to
refute or demonstrate a human health
hazard potential EPA is aware of two
more recent studies which discuss
increased cancer mortality among dry
cleaner worken. These studies have not
yet been comprehensively integrated
into the epidemiologic assessment for
PCE. It is not apparent, however, that
the influence of PCE alone can be
delineated since multiple solvents are
involved in one study and in the other
study in which PCE is the primary
solvent while the findings are
nonpoeitive. the exp-sed group was too
small to be useful in risk assessment. In
experimental animals, three types of
rumor* in rodents contribute to the
inference for a cancer causing potential
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3542 Fedaral RagJatar /- Vol. 56. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations
in humans. Indications of cancer activity
were seen In mice and rats, in both
sexes, by inhalation and oral exposure.
Short-term studies and other
information about PCE metabolism and
toxicity of the metabolites both
contnbute to the hazard concern as well
as provide some basis for hypothesizing
about tumor formation and relevancy for
human hazard assessment.
While there is lome uncertainty about
the relevance to humans of the animal
tumor endpoints. the totality of the
animal evidence is judged by EPA to be
sufficient to view PCE as • Category I
contaminant The lack of key
information does not support the uae of
the uncertainties to discount the
sufficient level of animal evidence.
EPA's response to a number of issues
raised m the public comments are
summarized below.
(1) Mouse Liver Tumor. The
controversy surrounding the liver tumor
response in the B6C3F1 male mouse is
well recognized, and EPA is aware of
the divergent scientific views regarding
the use of this animal endpoint in
carcinogen risk assessment. The Agency
undertook extensive review of this issue
while it was developing the carcinogen
risk assessment guidelines and in 1987
solicited PCE-related advice from the
SAB. The Agency's position is that .
mouse liver tumors are considered
evidence for potential human
carcinogenicity. The guidelines take the
position that the mouse liver tumor
response, when other conditions for
classification of "sufficient" evidence in
the animals are met (e.g. replicate
studies of matignancy, tumors at
multiple sites, etc.) should be considered
as "sufficient" endencs of
carcinogerrictry on a case by case basis.
In the March. 1888 letter reviewing
tetracfaloroHthyiena- issues, me EPA
Science Advisory Board concurred wrtk
the Agency's criteria for evaluating
mouse liver tumor responses.
(2) Peroxfiome Proliferation. In the
case of PCE. peroxisome proliferation
has been proposed as a plausible
mechanism for mouse liver tumor
development Although PCE and
metabotitB trichloroacetic add (TCA)
indues peroxisome proWexrtton and
tumors in the mouse liver, a cause and
effect relationship is not thereby.
defined. While peroxisome proliferation
may hare a role in mouse liver tumor
formation, the rola Is undefined. Other
plausible mechanistic hypotheses exist'
including those associated with
ger.otoxiary. There may be multiple
mechanisms involved in mouse liver
tumor formation. At the present time.
OA maintains the view that mouse liver
tumors are relevant for inferring a
potential for human health hazard
unless there is more definitive evidence
to the contrary.
(3) Manoauclear Cell Leukemia.
Mononudear cell leukemia, a neoplasm
that has been characterized biologically
and pathologically, was seen in both
male and female rats exposed to PCE.
Overall leukemia rates were statistically
significant in the males and marginally
so in females. When stage 3 leukemias
were counted, positive trends and
significafit increases in male and female
rat* were seen.
PCE caused a dose-related increase in
severity of monooucleax leukemia aad
shortened the time-to-tumor in female
rats. One commenter questioned the
relevance of this tumor to humans. EPA
does not consider k appropriate to rule
out a rodent neoplasm simply because it
has oo exact human counterpart Site
•concordance is not a requirement for
relevancy in the inference of Hazard
potential
Although a statistically rignifirant
increase in tumor incidence for a tumor
having a higk concurrent background
tumor incidence is consistent with
theory of promotion, this ebservaiiaa
does not identify the actual mechanism,
and thus several other ptausjhtti
mechanistic theorist of PCE-iodmced
leukemia development can not be ruled
out
A statistically significant increase ta
tumor incidence cannot be arbitrarily
dismissed wiiaout firm evidence
showing that mononuclear cell leukemia
in rats is a type of tumor response
isr'ated to this species and not relevant
to other potential tumor endpoints in
other specie*. Rather, EPA °««v""^ that
the experimental animal evidence
identifies the potential for a
carcinogenic response in humans uoleaii
there is evidence to the contrary.
(4) Uol* Rat Kidaiy Tuoor. PCE
increases the occurrence of aa
uncommon'renal tubular cell tumor ia
male rets. Recent research and
conventional lexicological Aint-Tng bans
suggested at least three plausible
explanations for tee tumor occurrence,
La, tka presence of a •nuyiy mole cat
renal protein. alpha-2u-giobuliK
presence of a secondary metabolic
pathway which produces a geaotoxic
compound in the kidney; anrl I-L« inj*.
nephrotoxitity and cellular regeneration
independent of the alpha-fti-globulin.
The EPA is presently developing criteria
wfeicb will dfifira a weight-of-tvidence
approach for evaluating, on a can by
case basis, the role of alpha-Zu-globulia
in rat kidney tumor formation. For
instance, if &e PCE data are
subsequently judged to be the only
definitive explanation for the occurrence
of male rat kidney tumors, this tumor
cndpoint aay have minimal relevance
for human health hazard assessment
This can be farther evaluated by EPA aa
criteria and PCE-apecific data become
available.
Given the presence of other plausible
mechanistic explanations, and the
currently incomplete picture about the
role of me PCE-rat kidney protein. EPA
views the rat kidney tumor endpoint to
be indicative of PCE exposure aad
relevant for consideration in the overall
weight of evidence for potential PCE
human healtfc hazards.
Cooaeqtiently, b^sed on the
information available to the Agency and
the public comments received on the
May, 1986 proposal EPA for the reasons
cited above coatiD«»« to place
tetrachloroetaylene in Category 1 and
promulgates aa MCLG of zero.
h. Tolm*at.
EPA proposed an MCLG of 2.0 mg/1
for toluene ia the November 1985
proposal and again in tka May 1989
proposal baaed on a NOAEL of 1.130
mgym" {root an aoanal study.
Public Comments. Two cosnmeaters
submitted information in response to
EPA's proposal for regulation of toluene.
The major health effect issues raiaed are
(1] use of rat ventilatory volume and
body weight IB calculating die rat total
absorbed doee bu*e»4 of aajnen
veatilatory voluae aad body weight
and (2) uee of a recently available 13-
week National Toxicology Program
(NTP) oral aduubtratioa st*dy rather
than the inhalation *tady need by EPA.
EPA Ratfoefe. EPA agrees with the
coBuneoter that tke rat ve&tibtory
volume aad body weight, inateed of that
of humane, be used for the calculaticm of
total absorbed dose. EPA also, agree*
with the suggestion by the commeoter
that UM NTP 1060 oral •dmieietretfOB
study is acceptable far the derhratioa of
the MCLG, because it it preferable to
uae valid oral studies, if available, for
the calculation of tke MCLG.
la me NTP study, groupe of rats were
administered toluene ia com oil et
dosage levels of 0, 312. 825,1.250, 2,500,
or 5.000 mg/kg tot five day*/week {or 13
weeks. Llver-to-braim ratio wa*
increased (e < 0.05{ in males receiving
the 82S-
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Federal Register / Vol 56. No. 20 /, Wednesday, January 30, 1991 / Rules and Regulations 3543
value) to 1 mg/l. Therefore, for the
reasons stated above, EPA places
toluene in Category in and promulgate*
an MCLG of 1 mg/L
;'. Xylenes. EPA proposed an MCLG of
10 mg/l (rounded from 12.mg/l) for
xy'.enes. EPA's proposal of 10 mg/l was
based on the NTP study involving the
administration of 0, 250, or 500 mg/kg
xylenes in corn oil by gavage to groups
of rats of'each sex for 103 weeks:
Public Comments. A total of six
individuals or organizations proTided
comments in response to the MCLG
proposal regarding xylenes. Three
commenters felt that EPA should not
round the proposed MCLG for xylenes
down from 12 mg/l to 10 mg/L On*
commenter felt that given the
uncertainty of the data presented In the
NTP study and the lack of clear
difference between the administered.
dosages. EPA should have considered
the low dosage (250 mg/kg) in the NTP
study as the LOAEL rather than the
NOAEL, Another commenter stated that
the NTP study of rats given xylenes In
corn oil by gavage for 103 weeks was
not an appropriate study for th« MCLG
for xylenes and suggested a teratogenic
* study in animals instead.
EPA Response. EPA believes the
rounded figure wag appropriate because
using more than one significant figure
would have implied a degree of
precision that was not warranted given
the large uncertainty factor (100) that
was used in deriving the MCLG. EPA
considered the low dosage of 250 mg/kg
from the NTP study in rats as the
NOAEL sines the mean body weights of
low-dose ar.:4. vehide control male raU
and those of dosed and vehicle control
female rsts were comparable. EPA also
considered that the NTP oral study in
animals was more representative of
xyle-ne's toxicity in drinking- water than
was the inhalation teratogenic study
(Mirkova et al., 1S33) guga&ated by the
coianietiier. The NTH oral study hi
animals entailed 103 ws-eks of exposure
to xylenes as comp-ared to only 21 days
of exposure to xylene-s via inhalatiou.
Available cancer inforsaation on xylene*
has been reviewed_by EPA and was
found to be inadequate for determining
potential carcinogenicity in humans.
For these reasons, EPA placet xylene*
. Ln Gate-gory EH and promulgates an
MCLG of 10 mg/l.
6. Pesticides/PCBs MCLGs
a AJachlor. EPA proposed an MCLG
<••' •>:?.•-.- fo- ss!«r.hl0r in the M^y 22,1989
proposal. Tfce MCLG v/se based on
8i:ffic",int evidence of carctnog-enicity in '
a:..-:.j.;'.js icLsssuicsiion of Group B2 by
FJ -\
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3544
Federal Register / Vol 56. No. 20 / Wednesday. January 30. 1991 / Ruleg and Regulation^
0,35 mg/kg/day in the two-year dog
study to calculate the MCLG for
alrazme. The fourth commenter
indicated that airazine should be-
class.fied .n Group B2 instead of C
because, ir. his opinion, the rat study
p:ov.ded "sufficient evidence" of
carcir.ogar.ic:ty: therefore, the MCLG
should be zero. In addition, he argued
(hat the Agency's rationale for
rlasssfvmg atrazine in Group C (see 54
FR 22062 at 22082) is misleading and
should have read: "Limited evidence of
carcinoger.icity. which means that the
data suggest a carcinogenic effect but
are limited because (a) the studies
invoke a single species, strain, or
experiment and do not meet criteria for
sufficient evidence (see Section
IVBlc):" * ') (52 FR33S99. emphasis
added)."
EPA Response. New information
became available to the Agency on the
1987 one-year dog study (Ciba-Geigy.
MRID 40313-01) that was used in the
calculation of the RfD and DWEL. This
new information (Ciba-Geigy. 1989.
MRID 412938-01) caused the NOAEL in
this sludy to change from 0.5 mg/kg/day
to 5.0 mg/kg/day. Since the Agency
usually uses the highest NOAEL in the
most sensitive species to calculate the
RfD. the two-generation rat study
discussed above with a NOAEL of 0.5
mg'kg/day (Ciba-Geigy. 1987. MJRID
404313-03) was selected as the most
appropriate study to determine the RfD.
Since the new RfD is the same in value
as the previous RfD. which was
calculated from the one-year dog study
in the May 22.1989 proposal, the DWEL
and MCLG will remain a.t proposed at
0,2 and 0.003 mg/1. respectively.
In response to the comment that
atraz:ne should be classified in Group -
82, the Agency disagrees based on the
fact that the increased incidence of the
mammary tumors (a tumor with a
generally high spontaneous background
in the rat) was noted onlyin one species
and one strain of rat.
.'..cordingly. EPA places atrazine in
Category II and promulgate* an MCLG
of 0.003 mg/1 for atrazine, as proposed in
the May 1989 proposal based on the
Changed basis for the RfD, as discussed
above.
c Carbofuran. EPA proposed an
MCLG of 6.04 mg/1 for carbofuran in the
May 22.1989 proposal. The MCLG was
derived from a DWEL of 0.2 mg/1.
applying a 20 percent contribution from
mr.K:ng water. Carbofuran is classified
.r. Group E (no evidence of
ca.-cmogerucity) by EPA. The MCLG of
0 0:6 .T-S ! irt thr November 13,1985
r:?pr>sal was rounded in the May 1989 •
prupcsa! to 0.04 mg/1. No new data that
would change the conclusions presented
in that notice have become available
since its publication.
Public Comment. EPA previously
addressed the public comments received
in response to the previous proposal of
November 13.1985 in the Federal
Register notice of May 22,1989. In
response to this notice of 1989. three
individuals or organizations commented
on the MCLG proposal for carbofuran.
One ccmmenter indicated that the
proposed standard does not protect from
immune system depression in humans.
Another commenter indicated that
additional negative immunological
studies were not discussed in the
carbofuran criteria document, in
addition, this commenter provided
corrections and editings to the
chemistry, occurrence and fate sections
of the criteria document. A third
commenter requested a change in the
NOAEL used in the calculation of the
RfD from 0.5 to 0.25 based pn
cholinesterase activity, thus indicating
that the MCLGs should be two-fold
lower.
EPA Response. EPA addressed the
issue of cholinesterase inhibition as the
endpoint of toxiciry in a special forum.
The 15 to 20 percent inhibition in blood
cholinesterase activity may be
considered a LOAEL. This level of
inhibition may be considered adverse or
non-adverse on a case-by-case basis
depending on the lexicological profile of
the chemical. In the case of carbofuran.
the NOAEL is based on the effects noted
on both the reproductive and nervous
systems. The chosen NOAEL of 0.5 mg/
kg/day was the appropriate NOAEL for
both systems; the uncertainty factor
applied to this NOAEL is 100-fold,
resulting in an MCLG of 0.04 rag/1. If the
lower dosage of 0.25 mg/kg/day was
selected as the basis of these
calculations, the applied uncertainty
factor (UF) would have been 10-fold
only because a larger UF would not be
justified based on the available toxicity
profile of carbofuran. Therefore, the
MCLG would have been higher than 0.04
mg/1. not two-fold lower. The choice of
the NOAEL of 0.5 mg/kg/day in the dog
study and the application of a 100-fold
UF were more protective to public
health because the NOAEL was based
on both endpoints of toxicity. testicular
effects and blood cholinesterase
inhibition, with an appropriate selection
of the UF as necessitated by the severity
of these endpoints.
In response to the commenters on
Lmmunotoxicity, EPA .believes further
research in this area is needed before .
any conclusion can be made on the
effect of carbofuran on this endpoint.
Consequently, EPA places carbofuran in
Category III and an MCLG of 0.04 mg/1
is promulgated. K.
d. Chlordane. EPA proposed an MCLG
of zero for chlordane based on sufficient
evidence of carcinogenicity in animals
(Group B2). While the proposed MCLG
of zero is based on the carcinogenici'.y
of chlordane. EPA provided a revised
DWEL of 0.002 mg/1 based on the results
of a newer chronic rat dietary study
(Yonemura et al.. 1983; 30-month chronic
toxicity and tumorigenicity test in.rats
by chlordar.e). This DWEL was
calculated assuming an uncertainty
factor of 1.000 (100 for the inter- anri
intraspecies differences ar.d 10 for the
lack of a second chronic toxici'y/
reproductive study) and consumption of
2 liters of water per day by a 70-kg
adult.
Public Com.-nent. One comrner.ter
stated that (1) chlordane was not
properly considered a "B2" carcinogen
since the EPA Carcinogen Assessment
Group (CAG) report (1986) could not
justify such a classification; therefore
the basis for a proposed MCLG of zero
was incorrect, and (2) EPA incorrectly
used an additional safety factor of 10 .
because of a lack of a second chronic
study in the derivation of the DWEL for
chlordane.
EPA Response. According to EPA's
guidelines, a Group B2 classification
(probable human carcinogen) is used
when there is sufficient evidence of
carcinogenicity.in animals and
inadequate data in humans. EPA
considers that chlordane i» correctly
proposed as a Group B2 carcinogen
because a number of rodent studies
(with fcT strains of mice of both
genders and F344 male rats) had clearly
demonstrated the induction of liver
tumors in animals following
administration of chlordane. In addition,
three compounds structurally related to
chlordane, ajdrin, dieldrin. and
chlorendic acid have produced liver
tumors in mice. Chlorendic acid has also
produced liver tumors in rats.
EPA has correctly applied an
additional safety factor of 10 in the
derivation of the DWEL due to the lack
of a second chronic study in animals.
EPA believes that the lack of adequate
chronic toxicity data and the lack of
data on reproductive effects require an
additional factor of 10. Therefore, EPA
places chlordane in Category I and an
MCLG of zero is promulgated based on
sufficient evidence of carcinogenicity in
animals and inadequate data in humans.
e. i.2-Dibromo-3-chloropropune
• (DBCP). EPA proposed an MCLG of zero
for.l.2-dibromo-3-chloropropane in the
May 22. 1989 proposal. The MCLG was
based on sufficient evidence of
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Federal RegUter / Vol. 56. No. 20 / Wednesday. January 30, 1991 / Rules and Regulations 3345
carcinogenicity in animals
(classification in Croup B2 by EPA
guidelines: Probable human carcinogen)
in the November 13,1985 Federal
Register notice. No new data which
change the conclusions presented in that
notice have become available since its
publication.
Public Comments. EPA addressed the
public comments received in response to
the previous proposal of November 13,
1965 in the Federal Register Notice of
May 22,1389. One commenter stated
that there is valid epidemiological
evidence to show that 1.2-dibromo-3-
chloropropane is not a human
carcinogen and that animal studies
unreliably predict carcinogenicity.
Consequently, this commenter
concludes overall evidence adequately
supports downgrading l,2-dibromo-3-
chJoropropane from Group B2 to Group
C by the EPA guidelines. If this is done.
the commenter recommends setting the
MCLG on the basis of non-carcinogenic
toxic effects with an adequate margin of
safety. The commenter states that 5
EPA continues the Group B2
classification for l,2-dibromo-3-
chloropropane, then the MCLG should
be set at a level corresponding to a
lifetime cancer risk of 10~4 to 10~§ or on
the basis of noncarcinogenic toxic
effects with an added margin of safety.
Using EPA's risk assessment the
commenter concludes that an increased
cancer risk in the range of 10~* to 10~§
would be at least 0.001 mg/1
{corresponding to a risk of 4 x 10"*):
therefore, the commenter feels the
MCLG should be set at 0.001 mg/1 or
greater. The commenter believes EPA's
proposed MCL of 0.0002 mg/1 it
unreasonably low considering the
carcinogenic potential and the
commenter's position that the half-life of
1.2-dibromo-3-chloropropane in water
guarantees th<-' ~..ost water systems will
reach the proposed MCL through natural
prccesse* within 15 year*. Another
.commenter agreed with the comment
that 0.0002 mg/1 is unreasonably low for
an MCL and felt that en MCL for 1.2-
dibromo-3-chloropropane should be 0.05
mg/l or higher.
EPA Response. Regarding the
epidemiological data for l,2-dibromo-3-
chloropropane. EPA believes the
epidemiology data base is inadequate to
either refute or demonstrate that 1.2-
dJbromo-3-chloropropane causes rumors
in humans. EPA believes there is
sufficient data to conclude that 1,2-
dibromo-3-chloropropane is
carcinogenic in animals since the
compound has been shown to be
carcinogenic in both rats and mice. EPA
U.-erefore has classified l,2-dibrozno-3-
chloropropane in Group B2: Probable
human carcinogen. Consequently, EPA
places 1.2-dibromo-3-chloropropane in
Category I and an MCLG of zero is
promulgated.
/ 2.4-D. EPA proposed an MCLG of
0.07 mg/1 for 2.4-D in the November 1985
proposal and again in May 1989 based
on adverse efferts on the liver and
kidney in test animals. EPA based this
MCLG on a NOAEL of 1 mg/kg/day, an
uncertainty factor of 100, and the
assumption that a 70-kg adult consumes
2 liters of water per day. EPA also
assumed that 20 percent of total
exposure of 2,4-D would be from
drinking water. No new relevant data
that change EPA's conclusions have
become available since publication of
the proposals. .
EPA also stated that it would consider
adopting an MCLG of 0.02 mg/1 for 2.4-
D. based upon the same study as was
used to calculate the proposed MCLG,
with the application of an additipnal
uncertainty factor of 3 to the
calculations. This uncertainty factor
would be applied to account for the fact
that supporting long-term data in dogs
were not available for 2.4-D.
Public Comments. One ccmmenter
stated that EPA ignored the two
National Cancer Institute (NCI) studies
linking exposure to 2,4-D with an
increase of non-Hodgkin's lymphoma,
and that since IARC classified
chlorophenoxy herbicides in Group B2
(limited evidence of carcinogenicity in
humans), EPA should do likewise.
EPA Response. EPA did not ignore the
two epidemiological studies published
by NCI that reported the possible
association of phenoxy herbicides (2.4-D
is a member of the class) with cancer.
Since the studies dealt with t class of
compounds, it is unpractical to
specifically link 2.4-D as a probable
carcinogen. In addition, the
contaminants in phenoxy herbicides
further cloud the results of these studies.
EPA'ii proposal for the regulation of
2,4-D was based on inadequate data for
the .cancer classification and its effects
of 2,4-D on the liver and kidney.
Controversy regarding the cancer
classification of 2.4-D has arisen
because of the recently published
epidemiological studies on phenoxy
herbicides, a class of compounds of
which 2,4-D is a member. EPA's Office
of Pesticide Programs (OPP) published a
notice in the Federal Register (October
13.1989) stating .that an external-panel
of experts would be convened to advise
the Agency on the carcinogenic
potential of 2.4-D. However, until the
panel of experts convenes and the
Agency accepts its results. EPA
continues to categorize 2,*-D as *
category III contaminant. Consequently.
EPA is promulgating the MCLG of 0.07
mg/1 for 2,4-D as proposed.
g. Heptachlor/Heptachlor Epoxide. ,
EPA proposed an MCLG of zero for both
heptachlor and heptachlor epoxide
baaed on sufficient evidence of
carcinogenicity (Group B2] in animals.
Since the May proposal. EPA has
revised the DWELs for heptachlor and
heptachlor epoxide. A revised DVVEL of
0.02 mg/1 (rounded from 0.0175 mg/1)
was calculated for heptachlor. For
heptachlor epoxide, a revised DWEL of ,
0.0004 mg/1 was derived. These
revisions of DWELs for heptachlor and
heptachlor epoxide do not affect EPA's
. ji. ilusions about carcinogenicity of
ih~.i chemicals; however, they are
presented to provide more information
on health effects.
. Public Comments. One organization
provided comments in response to the
MCLG proposal regarding heptachlor
and heptachlor epoxide. The commenter
stated that heptachlor and heptachlor
epoxide have been incorrectly classified
as Group B2 carcinogens and that EPA's
Carcinogen Assessment Group report
(1966) could not be used to justify such a
classification.
EPA Response. According to EPA's
guidelines. Group B2 (probable human
carcinogen) is used when there is
sufficient evidence of carcinogenicity in
animals and inadequate data in humans.
These guidelines also state that mouse
liver rumor data may be used to support
sufficient evidence of carcinogenicity.
The evaluation of the carcinogenic
potential of heptachlor and heptachlor
epoxide was based on a sufficient
number of rodent studies in which liver
carcinomas were induced in two strains
of mice of both genders and in CFN
female rats.
Consequently, as discussed above,
EPA places both heptachlor and
heptachlor epoxide in Category I and
promulgates an MCLG of zero as
proposed.
h. Undone. EPA reproposcd an MCLG
of 0.0002 mg/1 for lindane based upon a
DWEL of 0.01 mg/1, an additional
uncertainty factor of 10 since lindane
was categorized as a category II
contaminant (limited evidence of
carcinogenicity via drinking water
ingestion), and * 20 percent contribution
from drinking water. No new data were
received that change ths conclusions
presented in the November 1985
proposal.
Public Comment. One commenter
stated that the MCLG should be zero for
lindane since lindane was classified as
Group C (possible human carcinogen).
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3546 Federal Register / Vol. 56. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations
EPA Response. The only evidence of
carcinogenicity for lindane was in mice
and available data do not permit
definitive decisions on Us oncogenic -
potential in rats. Since this effect has
been reported in only one species.
hndane was placed ;n Category II. and
the MCLG values for Category II
substances are set based on the RfU. An
MCLG of 0,0002 mg, 1 for li.-.dar.e :s
promulgated as proposed.
/. .Methoxychlor. EFA proposed an
MCLG of 0.4 mg/1 for methoxychlor
based on a rat study which identified a
XOAEL of 5 mg/kg/day and applied an
uncertainty factor of 100. However, it
was also stated in the EPA proposal of
May 22.1989, that a recent teratology
study in rabbits for methoxychlor was
under review by OPP. No comments
were received during the comment
period.
Following the review by the OPP and
EPA's RfD Workgroup, an RfD of 0.005
mg/kg/day for methoxychle r was
recommended based on this teratology
study in rabbiti (5-7-90). In this
teratology study, a NOAEL of 5 mg/kg/
day was identified and an uncertainty
factor of 1.000 was applied consisting of
100 for the inter- and intraspecies
differences and an additional factor of
10 for the steep dose-response curve and
the incompleteness of the data base on
chronic toxicity. EPA has placed
methoxychlor in Category in but for
reasons discussed above the MCLG was
changed from the 0.4 mg/1 level, as
proposed, to 0.04 mg/1 in today's rule.
/, Poiychlorinated Biphenyls (PCBs).
EPA proposed an MCLG of zero for
PCBs in the November 1985 proposal
and again in May 1989 based on its
classification as a Group B2 carcinogen
(sufficient animal evidence, inadequate
human evidence).
Public Comments. Several
commenters submitted information in
response to EPA's May 1989 proposaj for
regulation of PCBs. Major health effects
issues were (1) inadequate evidence of
carcinogenicity in humans. (2) extent of
chlorir.alion and carcmogerucity, i.e.,
only PCBs with 60 percent plus
chlorinated mixtures have been reported
to be carcinogenic in animals, and (3)
non-tnutagenicity of PCBs. One
commer.'er supported EPA's MCLG of
0.5 jig/1 PCBs in drinking water. One
commenler recommended exploring the
feasibility of regulating PCBs baaed on
relative toxicity of PCB congeners, citjrtg
'.".e article,' Environmental Occurrence,
Abundance and Toxicity of
Poiychlorinated Biphenyl Congeners:
Considerations for a Congener Specific
Analysis" (McFarland and Clarke,
Environ. Health Perspect.. Vol. 81. May
EPA Response. EPA agrees with the
commenters that there is inadequate
evidence of carcinogenicity of PCBs in
humans. However, there is sufficient
evidence of carcinogenicity of PCBs in
animals, which places PCBs in Group B2
according to the Agency's cancer
guidelines. Therefore, according, to EPA
policy, the MCLG for PCBs i. zero. The
proposed MCL is 0.0005 mg/1, the
practical quantification limit.
•PCBs that are 60 percent chlorinated
have been reported to be carcinogenic in
animals, while PCBs with a lower
chlorine concentration (chlorine 54
percent) have produced cancer in
animals that was not statistically
significant. PCBs are complex mixtures
of chlorinated biphenyls. which can
contain up to 209 possible isomers: the
toxicity of these has not been fully
characterized. Therefore, it appears
reasonable to regulate PCBs as a class
of compounds with a cancer
classification of Group B2. FD/\ also
regulates PCBs as a class of compounds
rather than individual congeners.
EPA agrees that PCBs are not
mutagenic in a bacterial test system;
however, this method does not respond
to chlorinated hydrocarbons, including
PCBs. In addition, a negative mutagenic
test does not detract from the
carcinogenic potential of PCBs.
Therefore, for the above reasons, EPA
places PCBs in Category I and
promulgates an MCLG of zero.
7. Other Synthetic Organic Contaminant
MCLGs
a. Acrylamide. EPA proposed an
MCLG of zero for acrylamide in the May
22,1989 proposal based on a B2
classification for the chemical.
Public Comments. EPA reponded to
the public comments received in
response to the previous proposal of
November 13,1985 in the Federal
Register Notice of May 22.1389. One
commenter questioned the B2
classification citing the results of a new
acrylamide bioassay by American
Cyanamid which indicated that mouse
screening studies were not repeatable.
that human epidemiology studies were
negative, that acrylamide does not
produce point mutations, and the
acrylamide reacts preferentially with
protein.
EPA Response. The current B2
classification for acrylamide is based
primarily on the Johnson et al. study
(Toxicol. Appl. Fharmacol. 85:154-169,
1988). In this study, the authors reported
increased incidences of scrotal
meaotheliomas, mammary gland tumors,
thyroid adenomas, uterine
adenocarcinomas, clitoral gland
adenomas, and oral papillomas. In
agreement with the Johnson et si. study.
the more recent American Cyanamid
study reported statistically significant
increases in the incidences of mammary
gland tumors (fibroadenomas or
fibroadenomas and carcinomas
combined), scrotal mesotheliomas. and
thyroid neoplasms (adenomas or
adenomas and carcinomas combined) in
both sexes. The uterine
adenocarcinomas, clitora! gland
adenomas, and oral papillomas
observed in the Johnson et al. study
were not found to be increased in the
American Cyanamid study. However,
there was a positive dose-related trend
' in the incidence of malignant reticulosis
in the brains of females and an
increased incidence of astrocytomas
(CNS glial tumors) in both sexes at the
highest dose level in the American
Cyanamid study. After reviewing this
study, the Agency has concluded that
both studies demonstrate that
acrylamide administration resulted in
carcinogenicity at more than one site in
rats.
Since there are two positive cancer
bioassays, the fact that there is some
disagreement among the Bull et al.
studies (Cancer Res. 44:107-111.1984a.
and Cancer Lett. 24:209-212.1984b) and
the Robinson et al. study (Environ. Hlth.
Perspect. 68:141-145,1986) would not
affect the classification of acrylamide.
EPA has reviewed two human
epidemiology studies (Collins, American
Cyanamid Co.. 1984. and Sobel et al.. Br.
J. Ind. Med. 43:785-788,1986) and found
them to be inadequate for determining
the potential carcinogenicity of
acrylamide in humans.
Athough acrylamide does not induce
point mutations, it is a clastogenic agent.
inducing chromosomal aberrations.
dominant lethality, sister-chroman'd
exchanges, and unscheduled DNA
synthesis (Dearfield et al., Mut. Res.
195:45-77,1988). Furthermore, the results
of a mouse heritable translocation study
(Shelby et al.. Environ. Mutagen. 9:3283-
368, 1987) has sho\vn that acrylamide is
an effective iiducer of translocalions in
postmeiotic germ cells, suggestina that
acryiamide may pose a heritable risk
concern in mammals.
While it is certainly correct to state
that acrylamide preferentially reacts
with protein (Sega et al., Mut.. Res.
216:221-220,1989), it also reacts wilh
nucleic acids in vivo (Carlson and
Weaver. Toxicol. Appl. Pharmacol.
79:307-313,1979) and In v;iro (Solomon
et al.. Cancer Res. 45:3465-3470,1985).
Accordingly, it Is not po.sible to rule ou.
the possibility of acrylamide-DNA
interaction. Due to the two positive
acrylamide bioassays and other data,
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Federal Regisfer / Vol. 56, No. 20 / Wednesday. January 30. 1991 / Rules and Regulations 3547
FPA retains a B2 classification for
dcrylamide and places it in Category I
•vith an MCLG of zero.
B. Establishment of MCLS
1. Methodology for Determination of
MCLs
The SDWA directs EPA to set the
MCL "as close to" the MCLG "as is
feasible." The term "feasible" means
"feasible with the use of the best
technology, treatment techniques, and
other means, which the Administrator
finds, after examination for efficacy
under field conditions and not solely
under laboratory conditions, are
available (taking costs into
consideration)." (SDWA section
1412(b)(5)). Each Nation-' Primary
Drinking Water Regulation that
establishes an MCL lists the technology.
treatment techniques, and other means
which the Administrator finds to be
feasible for meeting the MCL (SDWA
section 1412(b)(8J).
The present statutory standard for
"best available technology" (BAT) under
1412(b)(5) represents a change from the
provision prior to 1988. which required
. EPA to judge feasibility on the basis of
"best technologies generally available"
(BTGA). The 1988 Amendments to the
SDWA changed BTGA to BAT and
added the requirement that BAT must
be tested for efficacy under field
conditions, not just under laboratory
conditions. The legislative history
explains that Congress removed the
term "generally" to assure that MCLs
"reflect the full extent of current
technology capability" [S. Rep. No. 58,
99th Cong.. 1st Sess. at 9 (1985)]. Read
together with the legislative history,
EPA has concluded that the statutory
term "best available technology" it a
broader standard than "best technology
generally available," and that this
standard allows EPA to select a
technology that is not necessarily in
widespread use, as long as it has been
field tested beyond the laboratory. In
addition. EPA believes thi« change in
the statutory requirement means that the
technology selected need not .
necessarily have been field tested for
each specific contaminant Rather. EPA
may project operating condition* for a
specific contaminant using a field tested
technology from laboratory or pilot
systems data.
Based on the statutory directive for
setting the MCL*. EPA derive* the MCL*
based on an evaluation of (1) the
availability and performance of . arious
technologic* for removing the
contaminant, and (2) the costs of
applying those technologies. Other
technology factors that are coniidered
in determining the MCL include the
ability of laboratories to measure
accurately and consistently the level of
the contaminant with available
analytical methods. For Category I
contaminants, the Agency also
evaluates the health risks that are
associated with various levels of the
contaminants, with the goal of ensuring
that the maximum risk at the MCL falls
within the 1"' to 10"* risk range that the
Agency considers protective of public
health, therefore achieving the overall
purpose of the SDWA.
EPA's initial step in deriving the MCL
is to make an engineering assessment of
technologies that are capable of
removing a contaminant from drinking
water. This assessment determines
which of those technologies are "best."
EPA reviews the available data to
determine technologies that have the
highest removal efficiencies, are
compatible with other water treatment
processes, and are not limited to a
particular geographic region.
Based on the removal capabilities of
the various technologies. EPA calculates
the level of each contaminant that is
achievable by their application to large
systems with relatively clean raw'water
sources. [See H.R. Rep. 1185. 93rd Cong..
2nd Sess. at 13. (1974): 132 Cong. Rec.
S6287. May 21.1988, statement of Sen.
Durenberger-l
When considering costs to control the
contaminants in this rule, EPA analyzed
whether the technology is reasonably
affordable by regional and large
metropolitan public water systems (see
H.R. Rep. No. 93-1186 at 18 (1974) and
132 Cong. Rec. S6287 (May 21.1986)
(statement of Sen. Durengerger)]. EPA
also evaluated the total national
compliance costs for each contaminant
considering the number of systems that
will have to install treatment in order to
comply with the MCL. The resulting
national costs vary depending upon the
concentration level chosen as the MCL.
The more stringent the MCL, the greater
the number of systems that may have to
install BAT in order to achieve
compliance. In today's rule. EPA has
determined that costs for large systems
and total national compliance costs at
the MCL are reasonably affordable and.
therefore, feasible. Therefore,
alternative MCLs were not considered
The feasibility of setting the MCL at a
precise level is also influenced by
laboratory ability to measure the
contaminant reliably. EPA derives
practical quantitation levels (PQL»)
which reflect the level that can be
measured by good laboratories under
normal operating conditions within
specified limits of precision and
accuracy. Because compliance with the
MCL is determined by analysis with .
approved analytical techniques, the
ability to analyze consistently and
accurately for a contaminant at the MCL
is important to enforce a regulatory
standard. Thus, the feasibility of
meeting a particular level is affected by
the ability of analytical methods to
determine with sufficient precision and
accuracy whether such a level is
actually being achieved. This factor is
critically important in determining the
MCL for contaminants for which EPA
sets the MCLG at zero, a number which
by definition can be neither measured
nor attained. Limits of analytical
detection require that the MCL be set at
some level greater than the MCLG for
these contaminants. In these cases. EPA
examined the reduction capability of
BAT and the accuracy of analytical
techniques PS reflected in the PQL to
establish the appropriate MCL level. .
EPA also evaluates the health risks
that are associated with various
contaminant levels in order to ensure
that the MCL adequately protects the
public health. For drinking water
contaminants, EPA sets a maximum
reference risk range 10'4 to 10~*excess
individual risk from for carcinogens at
lifetime exposure. This policy is
consistent with other EPA regulatory
program* that generally target this range
using conservative models that are not
likely to underestimate the risk. Since
the underlying goal of the Safe Drinking
Water Act is to protect the public from
adverse effects due to drinking water
contaminants. EPA seeks to ensure that
the health risks associated with MCLs
for carcinogenic contaminants are not
significant
Below is a detailed discussion of the
Agency's response to the comments on
the proposed rule and how today's
MCLs were detemJned. EPA is
reproposing for public comment the
MCLGs and MCLs for aldicarb. aldicarb
sulfoxide, aldicarb sulfone, barium, and
pentachlorophenol due to a change in
the health basis for the standard.
However, regardless of the final
standards which are established. EPA
believes the BAT and analytical
method* promulgated today will not be
affected by the new standards.
Consequently, those requirements are
promulgated today.
2. Inorganic Analytical Methods
In the May 1989 notice, the Agency
proposed a list of analytical methods to
be used for measuring eight inorganic
chemicals (IOCs) that it considered
economically and technologically
feasible for monitoring compliance.
-------
3546
Fsxkral
/ Vol. 56. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations
These method* are promulgated today
as proposed with the exception of the
revision* that will be discussed below
(see Table 9). These methods were
selected based on the following factors:
(1) reliability (i.e.. precision/accuracy)
of the analytical results: (2) specificity in
the presence of inte-rerences: [1]
availability of enough equipment and
trained personnel to implement a
nrttional monitoring program (i.e..
laboratory availability): (4) rapidity of
analysis to permit routine use: and (5)
cost of analysts lo water supply
systems. . "
Table 9 lists the analytical methods
that EPA is approving for use to comply
with the monitoring requirements. EPA
has updated the references to the most
recent editions of the manuals, including
the atomic absorption and emission
method* for metals: the transmission
electron microscope method for
sbestos; and the colorimetric.
spectrophotometric, pctentioraetric. and
ica chromatography methods for nitrate
and mtnte.
The reliability of analytical methods
used for compliance monitoring is
critical at the MCL Therefore, the
analytical methods have to be evaluated.
with respect to the accuracy or recovery
(lack of bias) and precision (good
reproducibility) at the range of MCL.
When NPDWRs are revised ox new
regulations are proposed, the Agency
examines all appropriate methodologies,
including any minor modifications of the
method that may have been approved
for limited use. and only those methods
which meet all the necessary criteria are
proposed- Public comments on the
applicability of these methodi are taken
into consideration when the rule is
finalized.
In view of this, only the analytical
procedures specified in this final rule
cd-i be used for compliance monitoring
aster this rule is promulgated. The
Agency is aware that minor
modification* to specific mathod» have-
been previously approved for limited
use by various laboratori**. Th**r
approval* will ceaae upon tfa» effective
date of this rule. New methods, new
applications of current methods, and
any modification to method approved in
the future will be published in th»
Federal Register, thus making tfasM
changes available to all laboratories.
a. Asbestos. Several ccmmantBrs
•ubmitted comments expressing
concerns with the following: (1) Thre
c vpensc of T ran amis turn Electron
Microscopy (TEMJ analysis for asbestos:
..:' 'he number otlaboraroneir available
v, ".h TEM capabilities: (3) the
quantitative analytical precision and
accuracy of the TEM. method: and (4) the
absence of other asbestos methods on
the list of methods. EPA recognizes that
TEM analysi* is somewhat more
expensive than other conventional
analyses for most analytes that.ara
regulated under the SDWA. However.
the overall national cost should be
lessened because of the • "duced number
of systems affected by the monitoring
requirement* after the vulnerability
assessment, resulting in a limited
number of samples for ai alyse*.
EPA believes that sufficient analytical
capacity will exist for those water
systems that are deemed vulnerable
because public water system* will have
approximately five year* from
publication of the final rule to complete
the monitoring (i.e., December 31.1995).
thus allowing the analytical capability
to develop. In addition. EPA i* currently
participating in a cooperative program
with the National Institute of Standard*
and Technology (MIST) to certify a pool
of laboratories that can perform
asbesto* analysis using the TEM
method.
A performance evaluation (PE) »ample
is currently being developed by the
Agency to assess laboratory
performance using the TEM method.
Furthermore, the EPA facility in Athen*
has produced interiaboratory and
intralaboratory (single laboratory)
studies to verify the method'*
performance and capabilities.
Otiier asbesto* analytical method*
were considered and evaluated but they
were found to be inadequate and
inferior to the TEM method. The Agency
has determined that TEM i» tht best
available technique because of its
specificity of asbesto* fiber* (chrysotile
versus amphibole), it* effectiv«ne*» in
distinguishing between asbesto*. and'
nona«be*to* fibers, and i«« ibility to
determine'the number of fibers per
volumt and fiber size (length and
width). Furthermore, the MCLG for
asbe*to* was anassed using dat*
resulting from TEM analyse*. The
analysis of waterborne asbe*to*vby
different techniques can yield radically
different results, unlike the methodology
of other analyts*. EPA bsdlevas it i*
imperative to ensure comparability that
the analytical technique required for
monitoring water quality sample* b« the
same a* that used to a**e*» the MCLG.
EPA, howervet. continues to desire-
additional screening methodology and
encourage* the public to inform the
Agency when a potential technique may
exist. If addibonaLmetnods become
available that meat the MCL
requirement. EPA will promptly update
the ruls to permit alternative* to me
TEM method.
b. Nitrate/Nitrite. Several
commenters addressed concerns about
the ability of laboratories to analyze
nitrite because of.it* unstable character
and associated analytical problems.
EPA evaluated the most recent available
data resulting from Water Supply (WS) .
PE studies *022-025, in which va: -us
approved methodi were used, to
determine laboratory performance for
nitrite. The acceptance limit* calculated
from this data for the EPA. State, and
non-EPA laboratories that participated
in the studies demonstrate successful
nitrite analyse* a* compared to the
acceptance limit* of the other regulated
contaminant* as summarized in table *2,
One commenter stated that there are
conflicting opinion* whether to use •
single (Waters method B-1011) or dual
(EPA Method 300.0) column
chromatography for nitrate analysis. .
EPA evaluated data.- from a
comparability study for both of the
method* and concluded that they both
were successful in analyzing nitrate, i.e..
precision, accuracy, and acceptance
limit* criteria wan met
Some commenters also objected to the
deletion of mercoiarimfitricbrucine
method far nitrate from the list of
methods; EPA evaluated the most recent
available data from the laboratories that
used the bracin* method foe WS PE
studies #020-025. The review of the data
demonstrated the inability of the
method to produce results that met the
acceptance limit* criteria, thus it*
elimination from the liat of approved'
methods.
c. Otbsr Inorgairic Analyses. Savaral
commenters stated thai EPA Method
200.7 (Inductively Coupled Plasms-
Atomic Emission Spectromethc Method
(ICP-AES)) without the appendix (BPA
Method 28&7A-) is applicable for the
analysis of barium and ckmminm and
objected .to its: omission- fren. the list of
methods. BPA concur* with, this
issetameot of the method and will
permit its us* as an additional optional
method for the analysts-of barium and
chromium, Howevaa that appendix
(200.7 A) mu*t b* foUoMiad in processing
drinking watar samples prior toJCP-
AES analysis for csjilmiimx because
Method 200.7 is not tansttut*. enons^r for
cadmium samples at m* MCL level in
this rule.
One commenter recommended the-
deletion of ma gaseous: hydride EPA
Method 270.3 for selenium from the list
of methods because of its referral to a
method mat is no longer cited. EPA
recognize* this inconsistency and has
.deleted this mathod from ths list o£
approved methods baoauso it is an
incomplete method that references
-------
Fod«r»i Regfeter / Vol. 56, N.
TABLE 16.—INORGANJC CONTAMBNANT AC-
CEPTANCE LIMITS AND PRACTICAL
QUANTtTATlON LEVELS
Inorganic
cot'ium*
rant
Btriufr. '....
C*dmuni..
Chromi-
um ._ „
Mercury
NrtriM
Nitme
Selenium..
MO.
(mo/0
2
0.005
0.1
0.002
10
1
0.05
Acceptance
Mmrta 9 leixzwory. a>» sampt* muet t»
ba
1 c - p«(,cc. ha«! or
,
HND. to pM
ay CM
M »m» at
by ionfl «
f** tampte container ihot*> be
1:1
G-gteee, herd or »oft.
' in ail c&aea, tampt«a it\a*t be enilyred er won trier coBecton m poeetote.
3 SOC Analytical Methods
~ VOC Sdethods, Most
supported tira analytical methods as
- —^SP? However, severel chengw.
r.r, ;• c'.f'Tficdtions of the propoaai tre
rr.&rig m liu* notice. Four comnienters
f-v- V*tJKxd-? SDI.Z and 524.2 iho*ld not
"-. „->.-.;.;.• R-iontfid. at this time. Tfe«
;• -.-.rr.is.ert>er« 1«>A ft wouid be difficult to.
implement thi use of capillary column
and that input should have beea
obtained from the laboratory community
that the methods ware not technically
availabfe-forroutine use. Three of the
comment era felt there was a problem in
meeting Lfcis quality control (QC)
requirements in the methods.
particularly for Method 524,2. One of tht
commenters reported difficulty with
water desorbing from tha trap (which is
used in the purge and trap devices to
retain VOCs for analysis}. Qu»
commenter feJt regulating cia- and trana-
1,2-dichloroethylenje separately forces
the use of Method S24.2 to «chasve
resolution, but pecmits oa-«latian of
oth*a VOC*. The caaaumter felt tkU
-------
3550 Federal Register / Vol. 56. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations
situation would necessitate the use of a
capillary column.
Method* 502.2 and 524.2 were
developed as a result of public
comment. EPA proposed MCLi for eight
VOCs on November 13.1985 (50 FR
48902). Commenters recommended the
use of capillary column techniques, and
EPA agreed and developed methods-
502.2 and 524.2. These were proposed in
the April 17.1987 notice (52 FR 12879)
and finalized in the July 8.1987 notice
(52 FR 25702).
Water desorption from the trap is a
problem common to all purge and trap
methods in EPA't 500. 600. and 8000
series. The problem is particularly acute
in Jie gas chromatograph/mass
spectrometry (GC/MS) method*, but can
be minimized by following the trap
bake-out procedures in 5 H-* in both
Methods 502.2 and 524.2.
When monitoring a large number of
unknown compounds with the
possibility of co-eluting substances, use
of confirmatory columns is necessary
even for GC/MS techniques. Method
524.2 allows the use of three different
chromatographic columns under four
different lets of operating conditions,
allowing a greater differentiation and
resolution of VOCs than any other 500
series VOC method.
EPA notes the QC requirements in
Method 524.2 are identical to those in
Method 524.1. These requirements were
demonstrated by three different analysts
using three different columns.
Summarized data for WS studies 20-
24 for the regulated and unregulated
VOCs indicate non-EPA. non-State
laboratories can successfully utilize
Methods 502.2 and 524,2. Approximately
500 labs now analyze VOCs. The use of
Methods 502.2 and 524.2 has also
increased as a res'— t of WS studies 2C-
24. Seventy-five percent of the labs
reporting a method use either Method
502.2 or 524.2. For these reasons. EPA
will continue to approve. Methods 502.2
and 524,2. -
b. Method A variability. Ten
commenters felt there were too many
methods for the individual pesticides
and that the available methods required
second column confirmation, resulting in
excessive costs. The commenters felt
EPA should wait until suitable GC/MS
methods are available before regulating
these pesticides. EPA assessed the
impact of regulation, if monitoring was
implemented for these pesticides, and
found the costs were not excessive.
estimated at S180 or less per sample. •
Furthermore, the vulnerability concept
m this regulation should limit the
number of water supplies that will
rnoru'.or any or all of these pesticides.
The commenler* further stated that if all
the pesticides were present at the same
time, particularly the multi-peak
residues, chlordane. toxaphene. and
PCBs. only GC/MS could distinguish
them.
EPA has in fact found through
numerous national surveys for
.pesticides and PCBs, including the
current National Pesticide Survey (NPS)
and other programs like Superfund. that
the pesticides in this rule do not all
occur at the same sites. However, EPA
agrees with the commenters that GC/
MS is the most economical procedure
and indicated in the May 22,1989
proposal that it was investigating GC/
MS methods. Data supplied by
commenters and EPA's Environmental '
Monitoring and Systems Laboratory
(EMSL) demonstrate EPA Method 525.
discussed below, which was proposed
for monitoring; unregulated
contaminants-, can be utilized as a
primary analytical technique for the
majority of the pesticides. Consequently,
for the reasons cited above. EPA is
promulgating Method 525.
c. Cleanup Procedures. Four
commenters took issue with the lack of
cleanup procedures for the pesticide
methods. Laboratory methods
addressing contaminants under the
SDWA are for finished drinking water.
Most of the pesticide methods listed
below were derived from the methods
used in the National Pesticide Survey;
cleanup techniques were not included in
most of the methods since experience
has shown even a clean ground water
sample does not usually need sample
cleanup, which would only add
unnecessary cost.
d. Pesticide Methods. Several
commenters pointed out that Method 504
is the same as Method 505. EPA agrees
that the methods are similar except for
temperature programnrng of the gas
chromatograph and that theoretically
the compounds run in Methods 504 and
505 could be run in the same analysis. In
the absence of persuasive data,
however, EPA believes it is better to
isolate the two volatility ranges in
separate analyses.
In an interlaboratory study of Method
505 (U.S. EPA Method Study 40). no
significant differences could bwj seen in
the recoveries of the analytes in reagent
water and ground water, which ranged
from 90 to 120 percent Precision as
represented by the relative standard
deviation (%RSD) ranged from 11 to 30
percent for the analytes in reagant water
and from 11 to 40 percent in ground
water. Both the interlaboratory studies
and Water Supply Studies indicated
Method 505 it not recommended to
analyze atrazine.
Several commenters complained
about the use of diazomethane as the
esterifying agent in Method 515.1. While
EPA laboratories have used this reagant
safely for many years. EPA agrees this is
a matter of concern and is attempting to •
resolve this situation. In the interim,
those laboratories that do not wish to
use diazomethane can use the
derivatization procedure in the packed
column methods currently cited in 40
CFR 141.24 (f) for 2,4=D and 2.4.5=TP.
Pentachlorophenol can be analyzed by
Method 525.
e. Method 525. Eleven commenters
commented about the lack of a GC/MS
method to cut down on the number of
methods, reduce the cost of compliance
monitoring, and provide a positive
identification.
EPA stated in the proposed rule that it
was investigating GC/MS methods for
.those analytes that use gas
chromatography. EPA Method 525,
"Determination of Organic Compounds
in Drinking Water by Liquid-Solid
Extraction (LSE) and Capillary Column
Gas Chromatography/Mass
Spectrometry," was proposed as an
analytical technique for monitoring
unregulated contaminants under
5 141.40, Special Monitoring for
Inorganic and Organic Chemicals. At the
time the rule was proposed, sufficient
data were not available for the
regulated analytes. During public
hearings and in the comment period.
data supporting expanded use of this
method were submitted by three
commenters, including EPA's
Environmental Monitoring and Systems
Laboratory (EMSL)i and from WS rtudy
23. An improvement evaluated by EMS1
was the use of C-18 LSE discs as well as
the C-18 LSE cartridges. In using
Method 525, analytes, internal
standard!, and surrogates are extracted
from water by passing a liter sample of
water through cartridges or discs coated
with chemically bonded C—18 organic
phase (liquid-solid extraction, LSE). The
sample components are eluted from the
LSE with a small quantity of methylene
chloride, which then is evaporated •
volume of to 0.5-1.0 ml The sample
components are identified and
quantified by using « high resolution
capillary column/GC/MS system. The
pesticides in this rule, were run with the
two extraction systems on three types of
mass spectrometer systems—ion trap.
magnetic sector, and quadrupole.
AJachlor, atrazine, chlordane,
heptachlor, heptachlor epoxide, lindane.
methoxychlor, and penUchlorophenol
can be extracted by the use of Method
525. The method specifies an accuracy
range for analytes and surrogates of 70
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Fwiwrai Re*i*tM / Vol. 56, No. 20 / Wednesday, tannery 30. 199V / F.ulea and Regulations 3SG1
o 130 percent and » precis ion Itss than
or equal to 30 percent, which th« luted
snalytes can meet Uie of Method 525
allows monitoring ef rpgulflt«rl and
unregulated compound* simultaneously
and can eliminate five other analytical
methods. Consequently, EPA. is •
promulgating EPA Method 52S for the
analysis of alachlor. atrazine. chlordane.
hepticHoT. heptachlor epoxide. lindane.
methoxychlor. and pentachlorophend.
/. PCS Analytical Methods. In the •
proposed rule. EPA stated it had
evaluated existing method* which, for
the meal part are adaptations of
chlorinated pesticide procedure*. EPA.
explained me difficulty in applying
these procedures to finkhed drinking
water due to the removal of specific
congeners by the treatment process. In
the proposed rule EPA. outlined an
approach which would give a
quantitative answer for total PCBs while
minimizing false pcsi ives.
Thirty-two commenters expressed
views on PCBs. Sixteen did not like the
current EPA procedure of Methods 505
and 506 to screen, and Method 508A for
Quantisation. Seven commenters wanted
EPA to develop a CC/MS procedure
before regulating PCBs. Plv»
commenters were concerned about false
pa&Uives gaierated by piichlorinatioa
orbipbenyl and related coapounds.
Seven commeeter* felt th* method
detection limits fMDLs); and PQLa were
too low or incorrect: they felt the
regulated community could not meet
then. The rest of Ae corainenters cited
problems with availability and cost of
methods, the unsuftability of Method
505, and the lack of performance
evaluation data.
EPA has evaluated various available
methods, as rtatzd shove. None of these
analytical scheme* give* * reliable
quantitative «nsw*r to etrvironmeatally
degraded PCS ssmpfes. nor were any
provided by the eorarowrten.
Accordingly, tire t*oyo«ed procedure far
PCB analysis is supported by
performance and i» made fimak
Because of poor particJ^afion by the
public sector laboratories, data utilized
from W*ter Suppiy (WS) studies 23-25
were from non-EPA, aou-SUte
' laboratories, Thee* data stowed that
these laboratories, could screen and
quaalitate down to 04 .jig/1 total PCB,
for commonly occurring aroclors such as
1242 and 1254 using the protocol itatsd
in the proposed rule. EPA ha*
delenninjed that these performance daUi
support the PQL of 0.0005 mg/1 for total
PCBt, The apparent discrepancy in the
MDLs obtained with icreening by
Method 505 or 508 and quantitation by
Method 508A indira'c that the MDLs far
Method SOSA represent toe amount of
the particular arodor needed to reach
the detection, limit of
decachlocobiphenyl. which is 7\ percent
chlorine. Typical axodor designations
1221 or 1260 represent 21 percent and 60
percent average chlorine content. •
respectively. Aroclor 1221 is composed
mostly of biphenjd. monochloro, and
d-ichterobiphenyl congeners with poor
sensitivity to electron-capture detectors.
giving it an MDL of 0.02 mg/1.
Conversion to the detection level of
decachlorobiphenyl takes only «
fraction of this amount. Conversely 1280,
an expected, shows little increase in
sensitivity •* decachlorobiphenyL
EPA evaluated the problem of false
positives with Method 506A. la th*
proposed rule. EPA required screening
using Methods 505 or 508 to ensure PCBs
were actually present. EPA explained
that these methods are not used for
actual quantitation because high
resolution capillary chromatographic
columns used in Methods 505, 508, and
508A can co-elute compounds such as
chlordane. thus adding to the ppperent
concentration of PCBs. Method 508A. by
converting, all the PCBs to decachloro-
biphenyL separates, this, total PCB from
potential co-eiutants due to its longer
retention time in the gas chromatograph.
This improved specificity adequately
compensate.* for potential
perchlor kiation of biphenyl or related
co inpcunds.
Intertaboratory studies-now available
for Method 505 and WS data indicate
Method 505. i* suitable as * screening
method for PCBs. WS studies indicate
about hatf the non=EPA. non-State
laboratories use Method 505 as a
screening method. EPA has looked at
the MDL for GC/MS methods, including
Method 525; and, et this tore, no GC/MS
technique will meet its requirement*.
EPA feels tke cost of the analyst* te
racjonable since the PCB screen- is don*
as part of the chlorinated p«ficid«
analysis.
g. YUC Performance Stuttie*. A
number of coramenters stated that they
were unable to meet the ±20 percent/40
percent, performance requirement* for
VOCs first established July a. 1987.
Updated WS studies 2O-24 indicate thai
EPA1* decision to ertetdisfe accaptsnca
limiU for VOCs «t ±4O percent of th*
true value foe concentrations less than
10 ;-s/l aocl ±20 percent al
roncentra'toB* 10 ng/1 or above was
Correct The result* of the** studies are
m the docket for this rule.
EPA originally expected the
percentage of private commercial
laboratories able to meet the specified
performance limit* to be much tower.
Summarized data for regulated aad
unregulated VOC* from WS20-24-
indicate improvement to the point that
there is no significant difference in
performance between the public and
private laboratories far most VOCs.
Private commercial laboratories show
continuing approvement o mey. gain
experience using the analytical
methodology.
Four commenters questioned the PQLs
established for VOCs in Phase 0. They
felt the original PQLs of 0.005 Hif/1 (5
Hg/1) based upon MDLs of 6.2-0.5 pg/1
reported by seven EPA and EPA
contract laboratories were erroneous.
The commenters feh theae stringent
PQLs resulted in MCL* for three
carcinogens—1.2-dichloro propane.
styrene. and tetrachloroethylene—that
many laboratories would not be able to
accurately measure.
EPA revised its VOC methods in
December 1988 with new MDLs. WS
data (WS20-24) indicate 60 to 75 percent
of reporting laboratories now 'use the
capillary column Methods 502.2 and
524.2. These methods- ha-ve MDL»
ranging from 0.01 to 0.05 fig/1 for the
VOCs in this regulation. The WS data
for WS studies show the laboratories
have bees challenged with at tamt one
sample at or below the 0.005 mg/1 PQL.
The performance data indicate that the
use of the O005 mg/1 PQL establishes a
level for adequate performance for non-
EPA. non-State laboratories.
iu Peslicide/PCB PQL aad
Performance Acceptance Limits. In the
May proposal EPA estimated pesticide/
PCB PQL* based on 10 times the
^iniTniim detection limit* (fiv« tirae* for
EDB and toxaphenej. EPA stated that
ongoing performance evaluation studies
would determiae-whether the estimated
PQLs are achievable. Performance data
now available from WS studies 22-24
(23-25 for PCBs) for the noa-EPA, non-
State laboratories show this approach
was jurti£ed. WS atndiaa 22-25 tad
value* bracketing the PQL/MCL for
most pesticide*, in some cases., the WS
data indicated the PQL could be
lowered from the levels pr^o^d in
M*yl98a
Fifteen cojnmeater* responded to
EPA's procedure* foe setting MDLs and
PQLs. Moot of them commenter* took
issue with EPA estimating the PQL* at
five times the IntBdaboratory Method
Detection Limit (D*£DL) far EDB end
toxaphane. Six commenters complained
about using the singta laboratory MDL
to set the PQL for PCBs. Two of the
commenters had the same complaint
about atrazine. Several eommcntfirs
stated that precision; and accuracy »re
sacrifietd to attain • lower level of
detection.
-------
Federal Register / Vol. 56. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations
Performance data now available from
WS studies 22-25 indicate non-EPA.
r.on-Siate laboratories can screen
pesticides for PCBs at 0.1 jig/1. The
mterlaboratory performance data
support the PCB PQL of O.S fig-"- Sata
for atrazine from VVS studies 22-24 and
from EPA Method Study =40 using
Method 507 support a PQL of 0 001 mg/1.
as proposed.
Several commenters cited the large
gap between some of the proposed PQLs
and the MCLs. EPA agrees, and in the
case of Silvex. 2.4-D. and.inethoxychlor,
has raisad the PQL. Raising the PQL '
should result in increased precision and
accuracy for most laboratories. Because
ir.e MCLa for SiJvex. 2.4-D. and
r.ethoxychlor are set at a level equal to
the MCLG. raising the PQL has no effect
on the MCL or the health basis of the
standard. In the case of toxaphene.
performance data indicated the PQL
should be lowered from 0.005 mg/1 to
0.003 mg/1.
Data showed that the PQLs for
aldicarb and aldicarb sulfoxide could be
lowered from 0.005 and 0.008.
respectively, to 0.003 mg/1. Likewise,
water supply data showed that the PQL
for pentachlorophenol should be raised
from 0.0001 mg/1. as proposed, to 0.001
mg/l. The PQLs for aldicarb. aldicarb
sulfoxide. aldicarb sulfone, and
pentachlorophenol are reproposed
elsewhere in today's Federal Register
for additional comment.
Acceptance limits have been
calculated from WS studies 22-25 usiag
regression equations derived from the
data. The acceptance limits were
calculated at a 95 percent confidence .
interval at the MCLG or at the MuL if
the MCLG was zero. The raw water
supply data were plotted both at the
acceptance limits and as a percentage
around the true value to find a point at
which 75 percent of the laboratories
passed. Most of the limits were
calculated from non-EPA. non-State
data due to poor participation of the
public sector laboratories. Table 18 lists
the acceptance limits for the 18
pesticides/PCBs in this rule.
TABLE 18.—PESTICIDE/PCS PRACTICAL QUANTITATION LEVELS AND ACCEPTANCE LIMITS
—
Ccrvtamir.ar.t
CSC?
ECB , ,
Aiacftiof t — r 1
Atrazm* , , ., ....
Ciiroc'ufan .„
Heoucnior . - -
.
PCSs >as D«cacnkxoaipfienyl) , . '
?tac**fl^tt •-.
AkJilarD ' . . ... ,
A»cat3 sultoxic* ' ,..•.- . .
2 4.0 , . . •-
24 5-TP ,...,. .,. -.
Final MCL
00002
OOO005
0002
0003
0.04
0.002
0.0004
0.0002
00002
004
* 0.0005
0003
0001
0001
0002
0,0001 '
0.07
0.05
Accoctanc*
limits
(percent)
±40
-40
-45
->-45
-45
-15
-45
±45
=45
±45
0-2OO
±45
-55
±55
±55
-50
±50
±50
Fnal POL
(mg/1)
OCXJ02
0.00005
0.002
0.007
0.002
0.0004
0.0002
O.OC02
0.01
O.OO3
0.003
0.003
0.003
0.001
Proposed
POL
OOO02
000006
3002
0 001
0.007
0.002
0.0004
00002
00002
C001
0005
0005
0008
0.003
0.0001
1 MCL a ma proposed tevw,
4 Selection of Best Available
" echnology
s Inorganics. To fulfill the
requirements of Section 1412(b)(6),
regarding the selection of treatment
techr.iques that the Administrator finds
in be feasible for meeting each MCL,
CCA proposed best available
•.e.hr.oicg'es (BATs) "or each of tne
T.orgar'.c contam.ns.Ts. as summarized
.r. Table 16 of the Federal Regif ter
No ice of May 22. 1369. BATs were
selected on the basss of documented
••••::c;ency in removal of eaJi
• jntammant. commercial availability of
he technologies, compatibility with
o'her water treatment processes, and
•'•>as%D!iity, Among the BATs proposed
v^9rs conventional processes, sucii as
.ime softening and coagulation/
f'i.ra'.ion. and less commonly applied
'•jcrmologiee such as activated alurr..:;a
•t-.d reverse osmosis. All BATs for each
,->orsanic contaminant were discussed
in the May 22,1989 proposal, and
extensive review of performance
information and lab. pi'ot, and full-scale
data are contained in EPA Technologies
and Costs (T & C] document* for each
inorganic .covered by the proposal.
These documents were referenced in the
proposal and are part of the official EPA
docket for this regulation. Ta'jie 6
summarizes the BAT for the inorganics
for today's rule. As discussed below, the
BATs (except electrodialysis) ar-
identical to those proposed in May 1989.
One commenter supplied information
regarding electrodialysis reversal (EDR),
a membrane technology, and asserted
that the information supplied to EPA
confirms the use of EDR as BAT for all
but asbestos of the inorganic
contaminants addressed in the proposal
of May 22. 1989. The information, much
of which had previously been submitted
to EPA and reviewed by EPA staff.
consisted of consulting engineering
studies, product literature from the
company that markets '.he technology.
correspondence records, Historical
information regarding applications of
electrodialysis for drinking water and
industrial wastewater treatment
technology and cost information, and
general discussions regarding the
capabilities of EDR and other
technologies in the treatment of brackish
waters.
The commenter sought a detailed
response from EPA regarding EDR,
formally requesting that EPA address
several (a total of six) points whicn
question EPA's rationale for excluding
EDR as a BAT for the seven subject
inorganics in the proposal. The
commenter requested EPA
documentation regarding its response •
previous electrodialysis related
correspondence, and also requested
EPA's explanation regarding any
- -exclusions of EDR as BAT in the final
regulation. The EPA Comment/
Response document contains the
-------
Federal Renter / VoL 56. No. 20 / Wednesday, ^nuary
detailed response of EPA to each of the
commenter's concerns.
EPA reviewed the commenrj
regarding electrodialysis (EDR),
including materials sent by the
commenter in January 1990 in response
to a request by EPA to provide clear •
data to support some of th* commenter's
uaims. Field tests and full-scale
operating data from dectrodialysis
plants treating public water supplies
confirm that EDR is capable of
efficiently removing banum (Q& percent
on average), nitrate (51 percent to 92
percent), and selenium (71 percent
removal). The EDR data, mo.t of wfcich
' ***** a^ Regulations- 3553
were collected during a study by
Mexico State University, demons:rate
that EDR technology is appropriate and
feasible, and that it is capable of
efficiently reducing source water
banum, nitrate, and selenium, as veil as
other frequently occurring salts foetid m
moderately brackish waters, Baseo. upon
the data submitted to the Agency by the
commented. EPA has concluded that
EDR is a BAT for removal of barium.
nitrate, and selenium.
In regard to the four other inorganic
contaminants that are subject to- this
regulation (i.e.. cadmium, chromium.
mercury, and nitrite]. EPA found that the
TABLE 19—EtECTRODiAtYS.s PERFORMANCE COMPARED TO
available data could not support a
conclusion regarding EDR as a BAT,
Many of the claims nwde by the
commenter were not referenced or
supported by actual data. EDR removal
efficiencies cited within the comments.
were generally lower than efficiencies of
proposed BATs. Therefore, EDR was
found not to be equivalent to the
proposed BATs in removal of the four
other inorganics. Table 19 illustrate* the
difference between the efficiencies of
removal obtained by applying th*
proposed BATs and thosa achieved by
EDR.
PROPOSED BATs
—n ••
Eiectrodiaty» '
Banum . —
C«d(TKum..
Chromium.
Mer,:ury _..
Nitrate :. ...
Nrtnte
Soiemum ..
- —
-
.......
I
I 9Q-98 percent
80-88 percent
82-99 percent
4CMCO percent
67-98 percent
1 67-69 percent
. 75-89 percent ...
•-
..—
— •
•
... 70-75 percent «...
...j 86-91 percent «...
I D»t» ncoocius.'ve
..! 51 -82 percent '...
... 70 percent'
..., 71 percent1
.....
Yet.
J No.
...'. Ho.
...i N«X
...i Ye».
...NO.
...JY~
In addition to the low EDR efficiencies
evident in the commenter-supplied
repor'.°. many of the data are
in-ppropriate because they were
collected at sites employing EDR to
separate and/or recover industrial
waa'ewater contaminants. Operating
conditions at plants treating drinking
v\ a'.er would clearly be different than at
plants treating industrial wastes. To
determine efficacy of treatment, EPA
rei.es on quality data obtained under
verifiable conditions which would be
replicated under typical drinking water
treatment conditions.
EPA would welcome reports, date,
ar.a any additional test re*ult« on the
EDR process applied to drinking water
so that in the future the Agency may be
ai:e to determine the statui of th»
technology as a potential BAT for
removal of any cofllanunant to be
regulated under tire SDWA.
Because EDR is a newly recognized
2AT for barium, nitrate, and selenium.
EPA feels mat it is appropriate to
describe some aspects of the EDR
process and addrtts treatment coats
associated with EDR application to
drinking water. ElectrodiiaJysis is a
membrane process that leparate*
ier.ned or charged (anionic and
Cbiisr.ic) substances in feed water by
ai'o'.vmg iorj to pass through transfer
membranes. The membrane* are
coat" ^ured in "slacks," parallel to one
anc'.her. aad eada rucceserve membrane
carries a direct electric current which is
either positive (cathode) or negative
(anode), in alternate fashion. Cation*
migrate through the cathode membrane
and anions migrate through the anode
membrane, yielding partially deionized
water and concentrated waatewater in
alternating stacks which flow out of the
unit, or are recycled or recirculated
through additional treatment stages to
reach the desired product
A modification and improvement to
the electrodialysis process is the
automatic reversal of polarity, from
positive to negative, of direct current
across each me.r.brane at regular 15 to
30 minute intervals. Automatic polarity
reversal causes ion movement to
reverse, switching product and
concentrate streams.. By this process.
foulants and scale tend to slough oB of
membranes and are purged along with
the waste stream. This self-cleaning
mechaniar* appears to extend
membrane life to 5 to 10 years. Another
advantage of EDR over other membrane
processes i« EDR's apparent ability to
achierre greater product recovery (up to
95 percent), thus producing a smal.er
water stream to dispose (Zelver, 19C9;
Zeiver 1990). Others have reported on
pilot-seals performance and cost of EDR
compared to rtvers* osmosis (RO) and
demonstrated the near equivalence of
these two process** in terms of
feasibility and projsctcd cost (Robinson
et al.. 1988: Boyli Engineering, 1999)-
AH available information was
reviewed in regard to conformity of EDR
with other 5D '.VA BAT requirements.
Compatibility of EDR with other
technologies, feasibility, ability to
achieve compliance at a reasonable cos.
and commercial availability of EDR are
equivalent to RO, another BAT for many
inorganics. In addition, electrodialysis
has a history of performance in the
water supply and industrial waste
treatment field* (about 25 years). As
with RO. Fi;R is more economically
applied where raw water i* moderately
brackish. i.e.. 500 to 2.000 pom dissolved
solids, which is fairly common m the
southern, cecils', and western United
States.
Cost analyse? provided by tue
commenter and those published by
others (OTA, 1968 JAW'.VA, 1S8* Bnros.
1989; Dykes and Conion. 1983: Conlon
and McCIelLin. 1963) indicate tie cost
feasibility of applying EDR and RO for
general desahing and for removal of
specific contaminants from water
supplies. Production costs are in th«
range of $1.00 to $2.50 per 1 ,CCO gallons.
including amortized cBpilal and
operations and maintenance for 1 to 10
MGD plants. Waste disposal vva deep
well iniectioa would be in the range of
$0 20 to S0.3U per 1.000 gallon*.
EPA estreated elsctrodSalysis waste
treatment/disposal costs m th«
September 1986 waste T*C *>«™n<'
(EPA. 1966). Waste disposal options ana
-------
1554 Federal Register' / 'Vol. 56. No. 20 /.Wednesday. January 30. 1991 , Rules and Regulations
Jssign and cost criteria for EDR were
•;ssumed to be equivalent to those for
RO. leading to identical cost curves.
EDR ar.d RO water treatment costs
c.'uld also be assumed to be equivalent:
EDR capital costs tend to be lower than
PO. but the consumption of electrical
power :o run an EDR plant offsets the
total production costs to the point of
nearly equalizing the overall cost of
applying the two technologies.
There should be no substantial
changes to the final regulatory impact
analysis (RIA) as a result of a new BAT
U e.. EDR) in the final rule because (1)
water production and waste treatment
costs for RO and EDR are ne irly
equivalent and (2) a relatively small
patrnent data available at the time of
dccument preparation, and which to a
great extent form the basis of EPA's
BAT determinations in regard to
treatment efficiency.
One commenter questioned the
practicality of RO and IE technologies
s-e to the wastes generated and the
amending difficulties related to waste
d.soosal. As referenced in the above
EPA response regarding EDR as a BAT.
Er>A ar.d others have studied and
•'-cunvirr.teJ the costs related to the
f2,1989.
Table 7 lists the BATs for the SOCs. As
discussed below, the BAT for each SOC
in today's rule is unchanged from the
May 1989 proposal.
(1) Why PTA Is BAT for Air Stripping
Several types of aeration technology
are useful for stripping volatilea from
water. Packed columns or towers have
been more widely studied and used to
reduce the compounds at the levels that
occur in drinking water. Diffused
aeration has been shown to effect
removal of certain SOCs and may have
some advantages under hydraulic or
space constraints. Other aeration
methods such as slat tray, spray, and
airlift pumping have shown good
removals in certain applications for
volatile organics. In all cases, results
vary depending on physical, chemical.
and design factors..Packed column
aeration appears to be the most efficient
method in terms of gas transfer, and
may also lend itself better to emissions
controls than would other aeration
methods. EPA considers PTA the best of
the aeration treatments, thus its
designation as BAT. A utility is free to
choose any method, however. BAT or
other, to reduce a contaminant to the
MCL as long as it performs adequately.
(2) PTA and Air Emissions
EPA received five comments
expressing concern that emissions from
PTA facilities were simply transferring
the chemical and the risk from the water
to the air. In the preamble to the
proposed rule. EPA addressed this
concern for two carcinogenic
compounds—EDB and DBCP. By
modeling the risks to populations
downwind from a packed tower
aeration facility, "it was apparent in the
cases examined that the risk resulting
from exposure to EDB or DBCP by
inhalation is several orders of
magnitude lower than that resulting
from drinking the contaminated water.
and that the amount of EDB or DBCP
adde'd to the air did not significantly
increase risks from airborne
contaminants." The maximum
indi\ _jal lifetime risks ranged from
10" • to 10"' for inhalation and 10"' to
10"* for drinking the same level. There
was at least three orders of magnitude
difference for any scenario examined
comparing ingestion to inhalation, as
-------
Regis*** / VoL 58. No. 20 / Wednesday. January 30. 1991 7 Rules and Regulations 3555
depicted in table 26 of the May 22.1389
proposal
However, since several States
regulate emissions fromPTA facilities'.
EPA is providing a table of costs for
emission controls on FTA units by the
use of vapor phase carbon. Table 20
presents the costs for different
compound* based upon a matrix of
combination* for ease of stripping and
the adsorbabllity of the compound. .
These costs are in addition to the cost of
the packed tower stripping itself.
TABLE 20.—ADDITIONAL COSTS FOR
VAPOR PHASE CARBON EMISSION COH-
TBOLS FOR PACKED TOWER AERATION
FACIUTV
Good SWppsMrty
(40:0):«
ca-1.3-
OtcNoro«thy1«o
0>chloro«thy1«rw> «...
EthylMnMn* •
McxiucNorotxn-
lene*
,120:1,,
Lm^lrff VLVm'
Styr*'* '
Grtltauf! Stnppatukty
(200: 1X»
EDff ' —
D6CP "
AcMtkxial costowFTA
trs>un«nt owiti/ 1.000
Smdl
syskMn
270
270
270
270
270-
270
27O
350
340
34O
390
368
um
ty««
15
15
11
tl
tl
11
tl
22
t«
1*
29
26
Unj.
sysMm
13
13
9
9
9
9
9
18
t1
*'
23
19
i1 Poor «por (*mti ortxjn ta*xuuum+^
« Mod«r*tt v«oor pft«*» carbon «d«ort)«o«»ir.
1 Strong v*por pr»>« csrtion ectextj«ti*ty.
ow Wm*«. Inc. Momowndun » Ow«
hufc«r. U S. EPA. F«oruwy W, 1»«0.
(3) BAT Field Evaluations
EPA received 14 coeasients that th*
SDWA requires fieW testing, not.jus*
laboratory testing, of tha applicability of
a technology to specific compound*
before the technology can b& designated
"best available" to achieve th» MCI.
Tho SDWA directs. EPA to sat the MCL
as close to tha MCLG as "feasible." The
SDWA defines "feasible" as "feasible
with the u&e of the best technology * * *
whi> the Administrator finds, after
examination for efficacy under field-
conditions and not solely under
laboratory conditions, [is] available
(taking costs into consideration)."
Section H12(b)(3)(D). EPA interprets
'.h:* provision to require field trials for a
technology, not far the application of
that technology to each individual
contaminant. Consequently, EPA has
not required full-scale field validation of
a technology's feasibility for treating a
specific contaminant if its effectiveness
has been demonstrated at bench or pilot
scale for that compound. The
technology, however, must reasonably
be expected to perform in a similar
manner under field conditions
regardless of aberrations due to scale-up
factors.
(4) Carbon Disposal Costa
Four commentera were concerned that
the cost of disposal of spent carbon was
not taken into account in the coating
assumptions for the design and O4M for
a facility.. The cost of carbon "disposal"
is essentially the cost of regenerating the
spent carbon (and replacing the 12 to 15
percent loat in the process). For plants
whose daily carbon nse is IMS than
1,000 pounds per day, EPA assumes that
the carbon would b* regenerated off-site
by the carbon supplier and that co»t is
included to the cost of replacement
carbon. For plant* whose carbon
demand i» more than l.OOttpeunds per
day, it is gcfinf ally economical to
regenerate on-site. The cost of the
incinerator used to regenerate the
carbon and its operation and
maintenance coet* are part of the
facility capital end O*M coats already
factored inlc total cost*. Tha revised
model that EPA now use* in developing
costs (Adams and Clark. AWWA. Jan.
198B) factors into, total costs the expense
of carbon regeneration and replacement
When powdered activated carbon
(PAC) is used, it if usually disposed of
with the alum sludge in e sanitary
landfill CannnenteTS expressed some
concern over the disposal costs should
the carbon prove to be a hazardous
wants. Because this- rule does not
consider PAC to be EAT. EPA is not
addressing die issue of PAC coats.
including the costs of disposal
(5) Powdered Activated Carbon a* BAT
Five coaanentera suggested that PAC
be considered BAT since it can be used
for removal of pesticide contamin*Uon.
in surface waters and is the same-
substance as GAG, EPA's position is
that the use of PAC may be an
appropriate choice of technology in
certain instances. PAC treatment of
surface water that is only intermittently
contaminated ^v pesticides or other
SOCs could be ooth economical, in
combination with an existing filtration
plant, and effective.
While PAC has proven effective in
taste and odor control, its efficacy for
trace SOC removal in drinking water is
variable due to factors soich as rarbon
particle size, background organics, and
plant efficiency, tt application of PAC
will reduce the contaminant below the
MCL, it may be used in lieu of another
less cost effective technology, even if
the latter is BAT.
(6) Empty Bed Contact Time
EPA received one comment suggesting
the 7.5-mimite design empty bed contact
time (EBCT) for GAC plants was shorter .
than the timee recommended by several
experts, including- EPA'* Adams end
Clark fJAWWA. Jen- W»)- EPA kes
used the 7.5-minute tontaet time
because multiplying it by the ratio of
design to average flows results irt at
least a 15-minute contact time fer ail but
the largest three systems, where 11.9
minuteo was the lowest average. A 15-
minute average contact time strikes- a
balance between the lower carbon
usage rates obtainable with longer
contact times and the higher capital
costs necessary to obtain, the longer
contact times by increasing contractor
size. Long contact tiraes also increase
the preloading of natural organlca which
may actually increase carbon usage
rates somewhat The model, which was
used to. develop costainthe proposal.
considered coat for EBCTs of 7.5 and
12.5 minutes. A 7.5-minute design fcBcri
was selected for the proposal as a
reasonable time, based upon peer
review.
However, based on this comment and
the study by Adams and Clark
(JAWWA. 1988J. EPA decided, to revise
the contact time. The EBCT was revised .
to 10 minutes at design flow using the
Adams, and Clark model, whish provide
a mor« complete and accurate estimate
of costs. The 10-minnte contact time at
design flow resulted in average flows
above IS minutes for all 12 system size.,,
and three minutes shorter at the 90
percentile leveLBesigning * Ii2-minute
contact time fei a 90 percentile flow rate
for each system size resulted in very
short design contact time for the smaller
systems.
GAC cost* as presented in Table 21 of
today's rule increased from those
presented Irt Tebla 27 of the proposal as
a result of (1) difference* in the cost
equations between the CWC model used
in the proposal and the Adams sad
Clark moaei used in this rule-. (2) the
costs for carbon storage labor and water
requirements for on-site carbon
transport were included in the revised
costs; and (3) the design EBCT in the
revised costs was 10 minutes, which
required a larger facility, resulting in
larger capital costs, than did the 7.5-
minute EBCT in the proposal. The
-------
3556 Federal Register / Vol. 56. ,NL^2oy Wednesday January 30. 1991 / Rules and Regulations
increases ranged from $2 to S6/
household/year (a 25 to 75 percent
increase) for large systems to $300 to
S310/household/year (a 46 to 55 percent
increase) for smaller systems. It is
significant that differences between
models, rather than the increase in
EBCT, caused most of the cost increase.-
In calculations for 0.1 and 0.45 lb/l.OOO
gal carbon usage rates, the differences
between models resulted in total
production cost increases of 21 to 44
percent for large systems and 38 to 53
percent for small systems. However.
changing the contact time alone from 7.5
to 10 minutes resulted in only a change
of 12 percent for large systems and 5
percent for small systems.
(7) Carbon Usage Rates
Two commentera pointed out that due
to the presence of background organics
the carbon usage rate (CUR) obtained
from distilled water isotherm data is
smaller than that obtained from full-
acale testing with natural water. The
concern was that costs of carbon
replacement and regeneration would be
much higher in actual practice than
those calculated in theory using the
lower CUR. The mass transfer model
EPA used to develop CURs was the
constant pattern homogeneous surface
difftisic^ model, which uses distilled
water isotherm parameters and kinetic
coefficients determined using literature
correlations.
Section 4 of the T * C document lists
CURs adjusted for background organics
in natural waters by using an
adjustment coefficient derived from a
linear regression of data points. This
adjustment reflects a ratio of field to
model CUR as s function of model CUTL
This coefficient Was developed after the v
May 22,1989 proposal and improves the
utility of the model. This improved
model is used as the basis for the costs
in today's rule.
EPA is aware that the correlation
between costs and CURs if not as good
for the well-adsorbed compounds such
as the pesticides, typically with low
CURs, Additional field data art needed
tn this area. However, costs ar« very
insensitive to changes in the CURs of
0,5-0.1 lb/l.OOO gallons. Mo«t of the
pesticides in question have low CURs.
A darns and Clark (1983) observed that
'there is only a small gradual increase
in cost between a two-year and a six-
ff.cr.th reactivation frequency."
Therefore, even though more data would
, -st'.'ul, EPA bcLi-ves thai o\ei>;..
costs for removal of the well-adsorbed
compounds would not be greatly
affected, if at all. Because the prediction
is only as good as the uniformity of the
water, the effect of the organic matrix
on the carbon will change as the matrix
changes in the influent water, despite
accurate scale-ups at specific points in
time. GAC adsorption behavior, and
therefore the CUR. typically varies
among different water matrices with the
same contaminant and operating
conditions. For the well-absorbed
compounds, longer contact times and
higher costs typically result from the
impact on CURs due to the adsorption
sites deeper in the bed being occupied
by natural organics that interfere with
SOC adsorption.
5. Determination of MCLs (Feasibility
and Cost)
EPA proposed MCLs for 36 chemicals
based upon an analysis of several
factors, including: .
(1) The effectiveness of BAT in
reducing contaminant levels from
influent concentrations to the MCLG.
(2) The feasibility (including costs) of •
applying BAT. EPA considered the
availability of the technology and the
costs of installation and operation for
large systems (serving more than 100,000
people).
(3) The performance of available
analytical methods as reflected in the
PQL for each contaminant In order to
ensure the precision and accuracy of
analytical measurement of contaminant*
at the MCL. the MCL is set at a level no
lower than the PQL
After talcing into account the above
factors, EPA then considered the risks at
the MCL level for the EPA Group A and
B carcinogens to determine whether
they would be adequately protective of
public health. EPA considers a target
risk range of 10~* to 10~* to b« safe and
protective of public health when
calculated by the conservative linear
multistage model. The factors EPA used
in it* analysis are summarized in tables
22 and 23 for the Category I and
Category D and ni contaminants,'
respectively.
a, Inorganic Contaminant MCLs. The
MCLi for tho inorganic contaminants
promulgated today are at the same level
as those proposed in May 198S (see
table 1). EPA is reproposing the MCL for
barium due to changes in the MCLG '
The MCL for each inorganic
contaminant is also at the same level as
the promujgated MCLG for each
contaminant. EPA has determined that
each inorganic MCL has one or more
BATs to reduce contaminant levels to
the MCLG, and that the BAT(s) is
feasible (as defined by the Act).
analytical methodologies are available
to ensure accurate and precise
measurement for each MCL. and each
MCL adequately protects public health.
Consequently, the MCLs (except for
barium) are promulgated as proposed.
b. Synthetic Organic Contaminant
MCLs
(1) Category I Contaminants
EPA considered the same factors in
determining the proposed MCLs for
Category I contaminants as for Category
II and ffl contaminants. However, the
proposed MCLGs for Category I .
contaminants are zero, a level that by
definition is not "feasible" because no
analytical method is capable of
determining whether a contaminant
level is zero. The lowest level that can
be reliably measured is the PQL. As
described above, EPA calculated PQL*
for the SOCs based on WS studies 20-
25.
In most cases, the PQL is identical to
that proposed in May 1989. In the case
of toxaphene, EPA lowered the PQL
based upon the WS studies. The MCL
for toxaphene is changed from 0.005 to
0.003 mg/1. Result* of WS studie* 20-25
indicate that the PQL for
pentachlordphenol should be set at 0.001
mg/1 rather than the proposed 0.0001
mg/1 level. Consequently, EPA is
reproposing the MCL for
pentachlorophenol at the revised PQL,
This issue it discussed more fully
elsewhere in today's Federal Register
'^proposing the pentachlorophenol
MCL. Because the PQL for toxaphene
represent* the lowest level feasible. EPA
is promulgating-thi* MCL at a level
equal to the PQL.
In the May proposal EPA estimated
the PQL for EDB a* five times the MDL.
Results of WS studies 22-25 confirm that
EDB can reliably be detected at 0.00005
mg/L Consequently, the MCL ia
promulgated as proposed.
EPA also calculated the per capita
costs for large systems to remove the
SOC contaminants to or below the MCL
using GAC or PTA. These costs range
from $10.00 to $44.00 per household per
year. EPA believes these costs are
reasonable and promulgates the MCLs
at the levels listed in Table 22.
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Federal Register / Vol. 56, No. 20 / Wednesday. January 30. 1991 / Rules and Regulations 3557
TABLE 21.—GAC AND PACKED COLUMN COSTS TO REMOVE SOCs
. y«*rl '
Compound
Volatile SCCs:
CfiyJbgntoni
TokMO* -
(rana-1 2-Dictitocoothytan* . - -
f*rttJ „._—.— .——.—.——«—
2.4,5-TP (S**ts) ...._
usage rate '
0.3966
.0446
.1234
.2867
.1637
.1453
.1930
.0605
.11*4
.3050
.3793
21 «8
.3619
.3718
.0371
.1032
.0543
,0570
.U379
.1224
.0556
.0271
.0203
.2137
rave
.0683
.0432
.0813
Small •
$950
•910
930
930
' 930
930
930
910
930
9 SO
950
930
950
950
910
930
910
910
910
930
910
910
910
810
910
910
910
no
GAC
Medium*
$76
96
51
51
51
51
51
36
51
78
78
31
76
76
38
51
29
36
38
51
36
36
36
51
»
36
36
36
Large4
$19
10
15
14
14
14
14
10
14
19
19
14
T9
re
TO
14
10
10
10
14
10
10
10
M
to
10
10
10
Small-*
$140
325
325
190
140
2 TO
T50
160
130
T50
130
140
140
140
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
MM
PTA
Medium-*
' i
$11 '
60 |
60 ;
23
12
T3
9
12
9
10
10
10
largr*
- - $7 \
*+ <
7
Percent
cflmcval a
90
90
93
93
90
90
• 90
90
96 7
90
90
t Coets Inakjde •mortaad ceeriaJ and -annuef operaOon and maiotenaaa*.
1 Percent remo»m!» from maxxnum jnflueot levels to at or betow lf>e-MCt_
Production IT Tcenti/1,000
• «*j*i to doHart per household per ye*/ (la.. 8 ct/1.000 saltont-
TASILE 22.—MCL ANALYSIS FOR CTTEOORY I SCCs
Aiart>(or
OfttCTiaM -, —
OfcrwnocfiiofacfciFierte (OflCP) . n. — — —
HerMacfitof
HeptacNor epooode «. ,
Pefrttchtoropneoof • —
Pot)'gNutiBiai%fl 1 1-1* • ij*i , ,,
Toxai>r»M ,,.. » , .. —
MO.G'
(mg/l)
0
0
0
0
0
0
0
0
0
0
0
MCL (mo/I)
CBD2
.002
JX302
X05
.00005
xtxx
.0002
.001
JDOQ5
.066
.003
0.002
.OOC
nrya
.005
.eooos
.0004
.0002
.001
fTff:
.086
.003
Amu^tioue
u*Jng
QAC
•10.00
10.00-
10.00
14.00
14.00
10.00
10.00
10.00
10.00
14.00
10.00
•hold eocts
»T«
PTA
$41.00
17.00
16.00
^^^^^ „..
- -
9.00
10-4rl«k
0.04
.003
.05
0.0006
0,03
0.0005
NotM
1 EPA pohcy is mat tor afi OBts^ciry I ijmilumiaiitiririe MCLG R> Tero.
« For laf?e mrteoe ***nt «rv»nB> 1.0OOJOO peopta.
• Progo^d MCLG aod MCL level EPA Mend* to promulgate a flnaJ MCL toy Ju»y 1991.
(2) Category n and HI ContaminanU
Far the Category JI and HI
contaminants listed in table 23, each of
the MCLt wai propotad equal to ill
propoaed MCLG. Becaiue MCLG* for
melhcxychlor, ttjTenfi, and toluene.
changed from the le-vela proposed in
May 1989. an d»cue«ed-above, the MCL*
also changed. Tke MCL for
melhoxychlor changed from 0>4 to AS*
mg/1; styren* changed from (M305/0.1 to
0.1; and toluene changed from 2 to 1 tng/
1. Each changed MCL U based on a
reasseflsment of the health data ai
disc us tred above.
Although PQLa for 2.4J5,
methoxychlor, and 2,* 5-TP change -from
the level* listed in the May 1988
proposal, «n»rh if (ffikiW-theMCLt
promulgated today and consequently,
doe* ntrt impact tfaete MOLs.
Section 1412 of the SDV«« requires
EPA to «et MCLs ai-clo»e to the 'MCLGs
as is feasible (taking costs into
consideration). EPA believe* that it is
feasible to set the MCLe «t the MCLG*
becau** (1) the PQL for each
conttminarrt i« crt Co.- betew 1he level
estsbliehad by the MCLG; (2) BAT can
remove each-contaminant to* ten\
equal, to or4»eloT* tbe MCUS; «nd (3) the
annual hoysetoid rofft to iru*eirBAT in
-------
3558 Federal Register / Vol. 56. No. 20 / Wednesday, January 30. 1991 / Rules and Regulations
large systems is a maximum of 519.00
per household per year and generally
around or below $10.00 per household are affordable for large systems.
per year. EPA believes that these costs
TABLE 23.—MCL ANALYSIS FOR CATEGORY II AND III SOCs
SOC conuminant
AMcirtJ • - ,.
AkxartJ tuHaaat • , •
AldiouD (ullon* •
Atraana,.........,, ,. .
Cwtioturin
yjt*mi serving > 1 000.000 p*op<«.
1 Propoawl MCLG «na MCL l^e-'s EPA in(«od» to prtxnu)g«t« final level* by ju»y 1991.
C. Treatment Technique Requirements
The principle sources of acrylamide,
epichlorohydrin. and styrene in drinking
water are impurities in water treatment
chemicals and surfaces in contact with
drnking water.
Because no standardized analytical
methods are available for acrylamide
and epichlorohydrin at low levels in
drinking water. EPA proposed a
treatment technique for acrylamide and
epichlorohydrin p->d provided guidance
for styrene.
EPA proposed to limit the allowable
monomer levels in products used during
water treatment, storage, and
distribution. These levels are:
Acrylamide:0.05 precent acrylamide
in polyacrylamide dosed at 1 ppm.
Epichhrohydrin: 0.01 percent residual
epichlorohydrin concentration dosed at
20 ppm.
Styrene: 1 ppm styrene in styrerie
copolymers used as direct additives and
as resin. Also, MCLs were proposed at
0.005 mg/l (as Category I) and 0.1 mg/l
(as Category II).
Under the proposed rule, a water
system using a product containing
acrylamide and epichlorohydrin must
certify to the State that the amount of
residual monomer in the polymer and
the dosage rate would not cause the
concentration in finished water to
exceed the specified level.
Summary of Comments: EPA received
25 comments on the proposal relating to
these chemicals. AJ] but fix commenter*
were generally supportive of the
"reposal Three commentera supported
—• tj: proaci adopted by EPA. Among
the comments received, 22 were on
acrylamide, 21 on epichlorohydrin and 5
on styrene.
Most commenters expressed concern
that the language in the proposal does
not clarify who does the testing for
monomer—the water system or the
manufacturer. It was suggested that the
language state that in annual
certification to the States, water systems
can rely on manufacturer's certification.
The commenters overwhelmingly
opposed the idea of water systems
performing the test for residual
monomer.
Today's rule is modified to make it
clear that a water system does not need
to test for monomers. A water system
can either test or rely on manufacturer1!!
certification or on third-parry
certification, whichever mechanism the
State is willing to accept.
Nine commenters suggested that the
issue of monomers in treatment and
distribution ajds should be handled
either by the States through a third-
party certification program or through
federal labeling requirements.
Under the SDWA. EPA can establish
and enforce maximum contaminant
levels or treatment requirements but
does not have the authority for
establishing labeling requirements for
proprietary products. As stated above, a
water system can either test the product
or rely on the manufacturer's
certification or on third-party
certification (e.g.. National Sanitation
Foundation (NSF)}, whichever
mechanism the State L» willing to accept
One commenter suggested
establishment of MCL» for these
chemicals. Since no analytical methods
(EPA-approved or otherwise) are
available for analysis of low levels of
acrylamide and epichlorohydrin in
drinking water, however, establishment
and enforcement of an MCL would be
impractical. Therefore. EPA has .
proposed a treatment-related
requirement rather than an MCL
Furthermore, EPA feels that the
proposed treatment-related approach is
a valuable preventive measure for
drinking water contamination.
One commenter felt that there is no
factual or procedural basis for regulating
styrene. This commenter offered two
supporting reasons: (1) Two '
manufacturers looked for styrene in ion
exchange resins but did not find any
(sensitivity of the method: 1 ppb); and
(2) styrene containing polymers and co-
polymers are subject to the third-party
certification program which should be
able to ensure safety.
According to the information
available to EPA. styrene is present at
low levels in styrene copolymers
intended for use in water treatment as a
secondary direct additive. This,
combined with the fact that styrene is in
wide industrial use and has been found
in 22 hazardous waste sitet listed on the
National Priority List Indicates that it
can be anticipated to occur in drinking
water. National Organic*
Reconnaissance Survey (NORS)
detected styrene in the water of three of.
eight citiee monitored,
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Federal Register / Vol. 56. No. 20 / Wednesday, January 30. 1991 / Rules and Regulations 3559
One commenter believed
epichlorohydrin should not be allowed
in flocculating agent* for drinking vyater
as it is a powerful contact mutagen.
With the proposed treatment
requirement, nominal epichkirohydrin
concentration in drinking water would
be 0.0022 mg/1. The upper bound
lifet.me cancer risk at this concentration
is calculated to be 6 x 10"1. This is an
extremely low risk considering that the
use of epichlorohydrin polymers and co-
polymers is widespread and highly
desirable because these materials are
effective in removing other drinking
water contaminants.
Consequently, with the modification
as noted above, the treatment technique
requirements for acrylamide and
epichlorohydrin are promulgated as
proposed. The guidance for styrene is
finalized as proposed
D. Compliance Monitoring
Requirements
1. Introduction
The proposed compliance monitoring
requirements (54 FR 22062) included
specific monitoring requirements for
inorganic contaminants (barium,
chromium, cadmium, mercury, and
selenium): nitrate/nitrite: asbestos;
volatile organic contaminants (VOCs);
and peslicidea/PCBs. EPA did not
propose compliance monitoring
requirements-for acrylamide and
epichlorohydrin because adequate
analytical methods did not exist for
these contaminant* at low level* in
drinking water.
EPA proposed that all community and
non-transient water systems comply
with the monitoring requirements for all
contaminants (except acrylamide and
epichlorohydrin) because of long-term
chronic exposure of these system's
consumers. Transient non-community
water systems were required to comply
with the requirements for nitrate/nitrite
only because of the acute nature of
exposure of these chemicals. The
coraplianc2 monitoring requirements
that EPA is promulgating today are the
minimum necessary to determine
whether a public water supply delivers
drinking water that meets the MCLs.
Though MCLGs and MCLs are being
reproposed for aldicarb, aldicarb
sulfoxide. aldicarb sulfone. barium, and
penlachlorophenol. "EPA anticipates
these will be promulgated by July 1991.
EPA believes that whatever level Ls
promulgated for aldicarb. aldicarb
sulfoxide, aldicarb sulfone, barium, and
pentachlorophenol would not affect the
monitoring requirements. Consequently,
the requirements promulgated today
a!so apply to aldicarb, aldicarb
sulfoxide. aldicarb sulfone. barium, and
pentachlorophenol.
The monitoring requirements that are
promulgated today generally follow the
three-tier approach first outlined on
October 5,1903 (48 FR 45502). Nitrate is
the only contaminant promulgated today
that falls in Tier I. The remaining
contaminants are regulated as Tier II
contaminants, a status that allows
Stales the discretion to increase or
decrease monitoring based upon •
established criteria and Bite-specific
conditions. Because of the low
occurrence of nitrite at levels above the
MCL, EPA has placed nitrite in Tier II in
this rule.
In developing the compliance
monitoring requirements for these
contaminants, EPA considered (1) the
likely source of drinking water
contamination. (2) difference* between
ground and surface v, ater systems. (3)
how to collect sample* that are
representative of consumer exposure, (4)
sample collection and analysis cost*, (5)
the use of historical monitoring data to
identify vulnerable systems and
subsequently specify monitoring
requirements for vulnerable systems. (6)
the limited occurrence of some
contaminants, and (7) the naed for
States to tailor monitoring requirements
to system- and area-specific conditions.
Although base monitoring
requirements lor surface and
ground water system* are the came for
all contaminants (except inorganic and
nitrate/nitrite), ground water system*
will qualify more frequently for reduced
monitoring and return more quickly to
the base monitoring requirement*
because (1) the sources and mechanisms
of contamination for ground and surface
water systems are different (2) the
overall quality of surface waters tends
to change more rapidly with time than
does the quality of ground water*, and
(3) seasonal variations tend to affect
surface waters more than ground
waters. Spatial variations are more
important in ground waters than in
5'irface waters since groundwater
contamination can be a localized
problem confined to one or several well*
within a system. Therefore, monitoring
frequency is an important .factor to
determine baseline conditions for
surface water systems, while sampling
location within the system generally is
more important for groundwater
systems. Today's monitoring
requirements generally require surface
water systems to monitor at an
increased frequency for longer periods
than groundwater systems.
EPAmonitoring requirement* are
designed to ensure that compliance with
the MCL* ia met and to efficiently utilize
State and utility resources. EPA's goal in
today's rule is to ensure these
monitoring requirements are consistent
with monitoring requirements
promulgated previously by EPA and
with known occurrence trends. The
monitoring requirements promulgated
today focus monitoring in individual
public water systems on the
contaminants that are likely to occur, an.
approach that includes:
• Allowing States to reduce
monitoring frequencies based upon
system vulnerability assessments fur the
SOCs (VOCs and pesticides/PCBs)
lilted in § 141.61(a) and (c) and for
asbestos.
• Allowing States to target monitoring
to those systems that are vulnerable to a
particular contaminant.
• Allowing the use of recent
monitoring data in lieu of new data if
the system has conducted a monitoring
program generally consistent with
today's requirements and using reliable
analytical methods.
• Encouraging the States to use
historical monitoring data meeting
specified quality requirements and other
available records to make decisions
regarding a system's vulnerability.
• Requiring all systems to conduct
repeat monitoring unless they
demonstrate through an assessment or
other da~ta that they are not vulnerable.
• Designating'sampling locations and
frequencies that permit simultaneous
monitoring for all regulated source-
related contaminants, whenever
possible.
• Else where, today in the Federal
Register EPA is proposing changes to
the monitoring frequencies that were
promulgated July 8,1907 for eight VOCs.
This change, when final, will require all
VOC sample collection for the 10 VOCs
in this rule and the .eight VOCs in the
July 8.1987 rule to occur at the same
time.
2. Effective Date
In the May 22.1989 Federal Register
Notice, EPA proposed to promulgate the
monitoring requirements under section
1445 within 30 day* of promulgation
because section 1445 imposes no
limitation* on when monitoring
requirements would be effective. After
18 months, the compliance monitoring
requirements would ineffective under
section 1412. The MCL* -and other
requirements would continue to be
promulgated under «ection 1412 and
effective in 18 months.
Moat commenter* did not support
making the .requirements effective
within 30 day* citing the confusion
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3560
Federal Register / Vol. 56. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations
between "new" and "old" regulatory
requirements. Other commenters cited
the lack of laboratory capacity for new
analytical methods. These commenters
stated that laboratones frequently do
not :nvest in capital equipment until the
raies are promulgated: consequently, the
18-month lead time before analysis must.
be conducted is necessary. Most States
cited their inability to adopt regulations
in less than 18 months and pointed out
that if they did not adopt regulations by
the effective date. EPA would have
primacy for the "new" rule while the .
States would retain primacy for
previous rules. The question of who
retains primacy could potentia1'"
confuse water systems. One co-nmenter
indicated that promulgating monitoring
requirements is beyond the intent of
section 1445. Numerous comrnenters
cited the impact on State resources to
review vulnerability assessments.
enforcement, reduced monitoring
decisions, etc.. as a rationale for
allowing States sufficient time (i.e.. 18
months before the monitoring
requirements are effective).
After reviewing the public comments,
EPA agrees that there is ths potential for
confusion in moving forward the
effective date for monitoring. In
addition, the Agency agrees that
implementation problems may occur in
beginning monitoring early.
Consequently, in today's action EPA
will promulgate the compliance
monitoring requirement* for regulated
substances under section 1412. All
morutonng requirements will be
effective 18 months after promulgation.
For contaminants that have existing
regulatory requirements (inorganics and
nitrate), the water systems must
continue to comply with the existing
requirements until they are superseded
by the new requirements.
3, Standard Monitoring Framework
EPA received extensive comments
stating that the proposed monitoring
requirements are complex and would
lead to confusion and misunderstanding
among the public, water utilities, and
Sttte personnel. Commentert also cited
the lack of coordination among various
regulations. Many commenters
suggested that EPA simplify, coordinate,
ind synchronize this regulations with
previous regulations. In response to
these comments. EPA has developed a
standard monitoring framework to .
address the issues of complexity,
coordination of monitoring requirements
among various regulations, and
synchronization of monitoring
schedules. This framework will serve aj
a guide for future source-related
rn ifijtonng- requirements adopted by the
Agency. The framework was developed
based on the proposed requirements, the
options and requests for comments EPA
discussed in the proposal, and 'he
comments received by EPA.
EPA believes that the framework will
in large measure address the comments
that recommended that reducing
complexity, synchronizing monitoring
schedules, standardizing regulatory
requirements, and giving regulatory
' flexibility to States and systems to
manage monitoring programs. EPA
believes these changes have the
potential to reduce costs by combining
monitoring requirements (including
vulnerability assessments) for.several
regulations on the same schedule and
promote greater voluntary compliance
by simplified and standardized '
monitoring requirements.
This framework will first be used in
today's regulation. EPA intends to apply
this framework to future requirements
for source-related contamination (i.e.,
VOCs. inorganics, pesticides, and
radionuclides).
Use of the framework envisions a .
cooperative effort between EPA and
States. The monitoring requirements
promulgated today are the minimum
federal requirements necessary to
ascertain systems' compliance with the
MCLs. In some cases. States will
increase the monitoring frequencies
above the federal minimum* to address
site-specific conditions.
For all contaminants contained in
today's rule, minimum (or base)
monitoring requirements may b«
increased or decreased by States based •
upon prior analytical results and/or the
results of a vulnerability assessment.
The monitoring requirements outlined
today follow to a large extent the
requirements proposed on May 22,1989.
In the May proposal EPA stated as a
goal to efficiently utilize State and utility
resources and be consistent with
monitoring requirements previously
promulgated by EPA. EPA believes that
today's requirements meet that goal.
a. Three-. Six-, and Nine-Year Cycles.
In order to standardize monitoring
cycles In this regulation (and in future
regulations), EPA is establishing nine-
year compliance cycles. Each nine-year
compliance cycle consists of 3 three-
year compliance periods. All compliance
cycles and periods run on a calendar
year basis (i.e., January 1 to December
31). This regulation establishes the first
nine-year compliance cycle beginning
January 1,1993 and e'nding December 31,.
2001: the second cycle beginning January
1, 2002 and ending December 31. 2010;
etc. (see { 141.2—Definitions). Within
the first nine-year compliance cycle
(1993 to 2001), the first compliance
period begins January 1.1993 and ends e"
December 31.1995; the second begins
January 1.1996 and ends December 31,
1998; and the third begins January 1,
1999 and ends December 31. 2001. EPA
in this regulation is also requiring that
initial monitoring (defined as the first
full three-year compliance period
beginning 18 months after the
promulgation date of a rule) must begin
in the first full compliance period after
the effective date. For today's
regulation, the effective date is July 30,
1992. Since the next full three-year
compliance period begins January 1.
1993. the initial monitoring period for
today'u regulation occurs in the
compliance period 1993-1995.
b. Base Monitoring Requirements. In
order to standardize the monitoring
requirements, EPA has established base
(or minimum) monitoring frequencies for
all systems at each sampling point.
These base monitoring frequencies
apply to all community and non-
transient water systems. In cases of
detection or non-compliance, EPA has
specified increased monitoring
frequencies from the base. These
increases are explained below. Systems
will also be able to decrease monitoring
frequencies from the base requirements
by obtaining waivers from the State
where a State permits such waivers.
Decreases from base monitoring
requirements through waivers are
discussed in general under the section
on decreased monitoring and in the
discussion of monitoring frequency for
each class of contaminants.
In most cases, these increased or
decreased frequencies in most cases are
-imilar to the frequencies proposed in
May 1989. Specific changes are
discussed below under each
contaminant group.
Inorganic contaminant base
requirements are the same ss
proposed—one sample at each sampling
point every three years for groundwater
systems and annually for surface water
systems. Modification of base
requirements for VOCs is discussed
below in the section on VOC monitoring
frequency.
For asbestos and pesticides, EPA
proposed that monitoring was not
required unless the State determined
that the system was vulnerable based
upon a State-conducted assessment.
States were required to complete a»i •
assessments within 18 months of
promulgation. If the State determine
that a system was vulnerable to
p¥sticide«/PCBs. systems were required
to monitor on a three- or five-year
schedule depending upon system size
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F*detal RagJBter / Vol. 56. No. 20 / Wednesday, fcnuary 30. Iflfil / Rules and Regulations
3561
»
and whether contaminants were
detected. For systems vulnerable to '
asbestos contamination, repeat
monitoring frequencies for «ib«stos of
every three years generally were
required based, upon ground/surface
water distinctions and the analytical
result of the initial sample.
The May 19«9 notice also included an
.alternative monitoring scheme which
would require all CWSs and non-
transient, non-community water systems
(NTWSs) to monitor for asbestos and
pesticidej/PCBs at specified (base)
frequencies. Most comments EPA
. eceived opposed a round of initial
•nonitoring by all systems. These
commenters cited the lack of occurrence
of pesticidea/PCBs in drinking water
and the expense of monitoring.
particularly for asbestos. Several
commenters questioned the availability
of sufficient laboratory capacity.
According to the proposed rule, if
States did not conduct a vulnerability
assessment for any one of the 80,000
water systems within 18 months and
determine system vulnerability, then the
system was deemed to be not vulnerable
and would not be required to monitor.
EPA's evalualion of the comments
revealed that States, in particular.
believed that their ability to conduct all
vulnerability assessments within 18
months would be limited because of
resource constraints on funds and staff.
Most States that commented cited this
resource shortfall as a major
impediment.
After reviewing aind evaluating the
comments, EPA is adopting the
alternative monitoring approach
discussed in the proposal for asbestos,
pesticides/PCBs, and unregulated
contaminants. EPA is making this
change for several reasons. First, EPA
believes requiring all systems to monitor
for pesticides/PCBs and asbestos is
more protective of health because
systems will be required to monitor if a
vulnerability assessment I* not
conducted. Second, after reviewing the
comments. EPA believe* that the
proposed rule was deficient in not
considering the inability of States to
conduct vulnerability assessments .
within 18 months. This change in today's
rule creates an enforceable requirement.
Finally, EPA believes the impact of
requiring a system to monitor for a
particular contaminant or not. is the
same under the proposed scheme and
today's requirements—provided a
vulnerability assessment is conducted
and a waiver is granted.
EPA has combined the above change
with the provision that systems may
conduct the vulnerability assessment
and, at the State's discretion, obtain •
waiver (see waiver cb'scuasiori below).
EPA has shifted the responsibility to
conduct vulnerability assessments from
States to systems because the
vulnerability assessment is a monitoring
activity that historically ha* been a
system responsibility. Each individual
system can decide whether to conduct a
vulnerability assessment (rather than
monitor) based on cost previous
monitoring hifltory, and coordination
with other vulnerability type
assessment* (i.e.. sanitary lurveys,
Wellhead Protection Assessments). In
addition, because of State*' indicated
resource shortfalls, vulnerability
assessments would not occur in many
States. Though EPA permit* *y*tems to
conduct vulnerability assessments.
approval of waivers based on those
vulnerability assessment* re»ts with the
States. EPA believes the changes
outlined above address, in part the
State resource issue and will result in an
enforceable drinking water standard.
In addition, EPA has simplified the
waiver procedure* to more fully apply to
situations involving pesticide* (see the
discussion of waivers below). The
changes outlined above wil) allow all
systems to apply for a waiver from the
monitoring requirements where State* '
provide for such waivers. Baaed on
limited occurrence data. EPA anticipates
that most systems should be granted a
waiver for most pesticides, asbestos,
and unregulated contaminants. In cases
where a system is not granted a waiver
by the State, it will be required to
monitor at the specified ba»e frequency.
Consequently, for the reasons specified
above, all systems will be required to
monitor for all pesticides/PCBs,
asbestos, and unregulated contaminant*
with an opportunity for reduced
monitoring based upon an assessment
c. Eight VOCs Regulated July 8, 1987.
In order to standardize the monitoring
requirement* for all VOCs, the repeat
monitoring frequencies promulgated for
tne eight VOCs (July 8.1987 rule) are
being proposed elsewhere in today's
Federal Register so that the
requirements in today's rule will be
identical for all 18 VOCs. EPA intends to
promulgate a final rule for the eight
VOCa by July. 1991. EPA i» proposing
this change iro a system that ha*
completed unregulated VOC monitoring
can monitor for all 18 VOCa using
today's increased or decreased repeat
monitoring criteria beginning in January
1993.
d. Increased Monitoring. Although it
is not po»aib)e to standardize
requirements for all contaminants, EPA
in this final rule seeks to standardize the
criteria that require a system to increase
monitoring from the base requirement*
and that allow the system to return to
the base requirement. In general, today's
rule require* monitoring frequencies to
increase when a contaminant is
measured at a certain concentration.
These concentrations are specified in
federal rules, and vary by class or
toxicity of the contaminant. In today'*
rule, these "trigger" concentrations are
set variously at the MCL 50 percent of
the MCL or the detection limit of the
analytical method used to measure the
contaminant. Specifically, the trigger
concentration* are (1) 0.5 mg/1 for
nitrite, 5 mg/1 for nitrate, and 5 mg/1 for •
nitrate/nitrite combined (each of which
is SO percent of the MCL); (2) the MCLs
for asbestos and five other inorganic
contaminant*: and (3) the analytical
detection limit* far VOCs. PCBa. and
pesticides. The detection limit for each
VOC is (X0005 mg/1. The PCBs and
pesticides detection limits are given in
Table 24. The rationale for varying the
detection limits for increased monitoring
is addressed in each section for the
contaminant monitoring frequencies
below.
After exceeding the trigger
concentration for each contaminant,
system* must immediately increase
monitoring to quarterly (beginning in the
subsequent quarter after detection) to
establish a baseline of analytical results.
Groundwater systems are required to •
take a minimumm of two samples and
surface water systems must take four
samples before the State may permit
less frequent monitoring. EPA is
requiring surface water systems tc take
a minimum of four samples (rather than
two for groundwater systems) because
surface water is generally more variable
than ground water and, consequently.
additional sampling is required to
determine that the system is "reliably
and consistently" below the MCI.
Today's rule allows a State, after a
baseline i* established, to reduce the
quarterly monitoring frequency if the
system ia "reliably and consistently"
below the MCL. "Reliably and
consistently" means that the State has
enough confidence that future sampling
results will be sufficiently below the
MCL to justify reducing the quarterly
monitoring frequency. Systems with
widely varying analytical results or
analytical results mat are just below the
MCL would not meet this criterion. In all
case*, the system remains on a quarterly
sampling frequency until the State
determines that the system is "reliably
and consistently" below the MCL. EPA
is adopting this approach based on
comments received on the proposed rale
that suggested the EPA allow States to
modify the monitoring schedules m
-------
3562
those systems which are less than the
MCL EPA believes this approach will
result in consistency among the
regulatory requirements for the different
classes of contaminants.
In the proposal. EPA required a
minimum of 12 quarters before the State
could reduce the monitoring frequency.
Several commenters suggested that a
minimum of 12 quarters after monitoring
had been increased by a trigger level
was too long. These commenters
suggested that EPA should require
sufficient monitoring to establish a '
baseline. As noted. EPA believes that
the minimum number of samples
necessary to establish a baseline is two
forgroundwater systems and four for
surface water systems. EPA is adopting
this approach because the Agency
agrees with commenters who pointed
out that systems whose analytical
results remain below the MCL do not
pose a health threat.
In the May 1989 proposal, a system
with any sample exceeding 50 percent of
Ihe MCL for asbestos and pesticides/
PCBs would be required to take a
minimum of 12 quarterly samples. If all
12 were ;\ assessment. In either -
v.a .-,• fey 'rule" or "vulnerability
assessment." the criteria for waiver are
Regulations
specified. Each is.discussed in more
detail below.
All waivers must be granted on a
contaminant-by-contaminant basis.
However, systems and States will find it
economical to apply for and grant the
waivers for those contaminants that
may be analyzed using the same
analytical methods. For example, since
measurement of pesticides or PCBs with
each analytical method would cost $800
for four quarterly samples, systems
should consider doing a vulnerability
assessment and applying for « waiver
for all contaminants covered by a
specific analytical method. This
packaging of assessments and State
decision making will yield significant
cost savings to both systems and State
primacy programs.
Waivers for the pesticides/PCBs and
VOCs may be granted after the system
conducts a vulnerability assessment and
the State determines the system is not
vulnerable based on that assessment. A
waiver must be renewed during each
compliance period. Waivers for
asbestos, based on a vulnerability
assessment, are also for three years but
or.ly need to be renewed in the first
compliance period of each nine-year
compliance cycle. Waivers for inorganic
contaminants [except nitrate/nitrite)
may be granted for up to nine years. If a
system does not receive a waiver by the
beginning of the year in which it is
scheduled to monitor, it must complete
the base monitoring requirement.
One change that EPA is adopting in
§ 142.92 is that EPA may rescind
waivers issued by a State where the
Agency determines that the State has
.issued a significant number of
inappropriate waivers. EPA does not
intend to utilize this provision except in
special situations where the State has
not fcllowed its own established
protocols and procedures that have been
EPA-approved during the adoption of
rules and procedures for this rule fsee
also fr°. discussion on State primacy
requirements). If a waiver is rescinded.
the system must monitor in accordance
with the base requirements in today's
rule.
/. Vulnerability Assessments. The
concept of vulnerability assessments
generated considerable comment. Most
commenters supported the concept of
using vulnerability assessments to
reduce monitoring but had questions
about how to conduct the assessments.
Comments ranged from requesting EPA
to provide specific guidance on how to
conduct an assessment to agreeing that
the criteria EPA specified in the
proposal were correct. EPA has decided
that a detailed protocol for what is
usually a very site-specific analysis is
not appropriate. Instead. EPA desires
that each State develop its own specific
vulnerability assessment procedures
that use the general guidelines
established by EPA. If a State chooses
not to develop these procedures.
systems cannot receive waivers and
must monitor at the base requirements
In today's rule EPA made several
changes to the vulnerability assessment
criteria for VOCs and pesticides/PCBs
In the proposal. EPA listed six criteria
systems must consider in conducting
vulnerability assessments for
pesticides/PCBs: Previous analytical
results; proximity of the system to
sources of contamination;
environmental persistence; protection of
c,^«tersource: nitrate levels: and use
ot PCBs in equipment. For VOCs, the
criteria were previous monitoring
results, number of people served
proximity to a large system, proximity to
commercial or industrial use. storage or
disposal of VOCs, and protection of the
water source.
pA is making several changes to the
vulnerability assessment criteria and the
process to simplify the procedure. First
a two-step waiver procedure is
available to all systems. Step *i
determines whether the contaminant
was used, manufactured, stored,
transported, or disposed of in the area.
In the case of some contaminants an
assessment of the contaminant's use in
the treatment or distribution of water
may also be required. "Area" is defined
as the watershed area for a surface
water system or the zone of influence
for a groundwater system and includes
effects in the distribution system. If the-
State determines that the contaminant
was not used, manufactured, stored,
transported, or disposed of in the area.
then the system may obtain a "use"
waiver. If the State cannot make this
determination, a system may not receive
a "use" waiver but may receive a
"susceptibility" waiver, discussed
below. Systems receiving a "use"
waiver are not required to continue on
to Step #2 to determine susceptibility
EPA anticipates that obtaining a "use-
waiver will apply mostly to pesticides/
PCBs where use can be determined
more easily than for VOCs. Obtaining a
' use" waiver for the VOCs will be
limited because VOCs are ubiquitous in
the United States. If a "use" waiver
cannot be given, a system may conduct
an assessment to determine
susceptibility. Step #2.
Susceptibility considers prior
occurrence and /or vulnerability
assessment results, environmental
persistence and transport of the
-------
Federal Register / Vol. 58, No. 20 / Wednesday, January 30. 1991 / Rules and Regulations.
chemical, the extent of source
protection, end Wellhead Protection
Program reports. Systems with no
known "susceptibility"' to contamination
based upon an assessment of the above
criteria may be granted a waiver by the
State. If "suscepubility" canr.ot be
determined, a system is not eligible for a
waiver. A system must receive a waiver
by the beginning of the calendar quarter
in which it is scheduled to begin
monitoring. For example, if a system is
scheduled to begin monitoring in the
calendar quarter beginning January 1.
1993, it must receive a waiver by
December 31,1992 for reduced
monitoring to apply.
Several commenters requested that
EPA permit "area wide" or geographical
vulnerability assessment
determinations. Though EPA at this time
is skeptical that "area wide"
determinations can be conducted with
sufficient specificity to predict
contamination over a large area, EPA
will allow this option when States
submit their procedures for conducting
vulnerability assessments determine
"use" waivers.
EPA's goal is to combine vulnerability
assessment activities in other drinking
water programs with today's
requirements to create efficiencies. EPA
also desires to use the results of other
regulatory program requirements, such
as Wellhead Protection Assessments, to
determine a system's vulnerability to
VOC and pesticide/PCBs
contamination. Systems and States may
schedule today's asssessments with
sanitary surveys required under the
Total Coliform Rule (54 FR 27548),
watershed assessments, and other water
quality inspections so that all
regulatory, operational, and managerial
objectives are met at the same time.
EPA intends to issue a guidance that
w.ll give flexibility to States in
conducting vulnerability assessments
and allow them and local public water
systems to meet these and similar
requirements under the Wellhead
Protection Program, latisfyirig the
requirements of both programs with one
assessment. Additionally, this combined
assessment approach may be used to
meet similar requirements under the
evolving Underground Injection Control
(UIC)—Shallow Injection Well Program.
g. Relation to the Wellhead Protection
[WHP) Program. The Agency planned to
Integrate particular elements of the
Public Water System Wellhead
Protection, and UIC programs related to
contaminant source assessments around
public water supply wells prior to
receiving comments to that efftTct.
Comments received on the proposed
F'hase II Ruie reinforce and support tliia
interest. Specifically, the Agency plans
to prepare a guidance document on
groundwater contaminant source
assessment that merges the
vulnerability assessment of the PW3S
program for pesticides and VOCs with
the wellhead delineation and
contaminant source which can be used
to establish priorities of UIC wells. This
integration is expected to assist State
and local drinking water program
managers responsible for goundwater
supplies to more efficiently and
effectively administer the portion of
their programs addressing source
protection and will be the basis for
determining monitoring frequency. The
guidance will give States flexibility in
revising vulnerability /contaminant
source assessments, a concern of
several commenters.
Notably. Section 1428 of the SDWA
requires each State to submit a WHP
program for EPA review and approval.
The implementation jf WHP programs
by States may be phased in to allow
resources to be used most effectively.
This matter can be addressed in the
State WHP eubmittal.
When States submit WHP programs
for approval in the future, program
documents should address how the
State will phase requirements for
Wellhead Protection Areas (WHPAs)
with other PWSS regulations. In some
States, to be moat effective, this program
integration may need to be
accomplished through a coordinating
agreement or other mechanism among
several State agencies. The guidance
would allow States to tailor their
program provisions to conditions in the
States, within broad guidelines.
Information from the other related
groundwater programs (such as
Superfund. RCRA) will be useful in this
assessment, aa pointed out by one
commenter. This information also
includes identification of sources not
regulated under federal programs, but
perhaps regulated by States, such as
septic tanks. Therefore, States may b«
able to meet similar requirements of
these three programs through following
a general set of guidance procedures.
One commenter was concerned about
the difficulty of delineating wellhead
protection areas, A State may choose
from several methods to delineate
WHPAs. As long as the method is
determined to be protective, a State may
choose a simplified mediod described in
' Guidelines for the Delineation of
Wellhead Protection Areas" (June 1987,
available from the Office of Ground-
Water Protection, U.S. EPA. EPA 440/6-
87-010). If a State desires more
information for use in the decision-
making process, it may choose more
sophisticated methods identified in the
"Guidelines." EPA hsd made a"va.ilab: J
to Spates and local agencies computer
software and training for use of the
"Guidelines" to mako the process of
WHPA delineation less difficult.
Additionally, one commentsr was
concerned about inclusion of recharge
areas in WHPAs. WHPAs may
incorporate recharge areai as long as
' they are within the jurisdiction of the
agencies identified in the EPA-approvec
programs. However, WHPAs must meet
the requirements of this rule if they are
to be used to make monitoring waiver
determinations. The State cannot accep
a WHP program in lieu of a vulnerabilit;
assessment if the recharge area is not _
covered to meet all the requirements of
this rule.
Once a WHPA is delineated, a State
may desire to apply a range of
assessment measures to define
hydrogeologic vulnerability within the
delineated area. A State may decide a
method of assigning priorities to the
public water systems based on
vulnerability, size, or other criteria
acceptable to EPA. While one
commenter indicated that DRASTIC
• (one method of characterizing a
hydrogeologic setting) was useful in that
State for describing hydrogeologic
factors affecting the physical-geologic
vulnerability of an area, it does not take
the place of delineating the zone of
contribution to wells. Furthermore, the
'use and disposal of chemicals and other
wastes are also factoni affecting an
area's vulnerability to contamination.
EPA's Office of Ground-Water
Protection is developing a Comparative
Risk Ranking and ScreenJig System to
help States and local water supply
managers prioritize potential
contaminant sources in carrying out
'their programs for resource protection, a
concern of one commenter. This system
could also be used in setting monitoring
priorities but was not designed
specifically for that application. As
another commenter indicated, the States
may use the regulatory mechanisms
available to them (RCRA permits.
NPDES permits) to determine the point
sources of regulated, and potentially
contaminating, substances in or near'
areas needing protection, such as
wellhead and recharge areas.
One commenter believed that drought
planning was more important than
contingency planning for alternate
sources of drinking water due to
contamination by chemicals. Drought
planning is very important in many
locations and needs to be conducted..
However, section 1428 specifically calls
for contingency planning in the event of
-------
20 / Wednesday. January 30
3564 Federal Register / Vol
contamination of public water wells m
wellhead protection areas, Contingency
planning could be integrated with
drouaht planning, and in many locations
tnti same sources.of water may. be used
in either situation as alternate sources .
o:' drinking water.
One commenter was concerned about
fund- r.g for both the Wellhead
Protection Program and '.he Sole Source
A^.'ifer Demor.strat.on Program in
Crtucal Aquifer Protection Areas. In
fiscal year 1990. EPA is supporting
State's activities in developing WHP
programs. To date. 29 States have
submitted documents for approval. Of
these, four State wellhead protection
program have been approved at this
t.me. It is expected that more programs
will be approved by the end of the fiscal
With respect to the Sole Source
Aquifer Demonstration Program for
Critical Aquifer Protection Areas, no
funding has been appropriated for this
program for the period FY 1987-1990.
and as a result, no such areas have been
identified. .
h. Initial and Repeat Base Monitoring.
Initial monitoring is defined as the first
full three-year compliance period that
occurs after the regulation is effective.
As discussed earlier, all systems must
monitor at the base monitoring
frequency unless a waiver is obtained.
The initial monitoring period for today's
regulation begins January 1.1993 and
ends December 31.1995. After the
system fulfills the initial (or first) base
monitoring requirement, it must monitor
at the repeat base frequency. Generally
the repeat base frequency is the same as
the initial monitoring frequency but in
several instances the base monitoring
frequency is reduced based on previous ,
analytical results (e.g.. nesticides/PCBs).
In the May 1989 proposal, for the
VOCs and pesticides/PCBs. community
systems serving more than 10.000
persons were required to complete all
monstonng within 18 months of
oromulgation. systems serving 3.3OO to
10.000 persons were required to
complete monitoring within 30 months.
and systems serving fewer than 3,300 •
persons were required to complete
monitoring within 54 months. Non-
transient water systems were required
to complete all morutonng within 48
months. In today's rule EPA eliminates
the phase-in of monitoring based on
svsten: size.
" In today's rule. EPA requires all
system* to complete initial monitoring
,either by sampling or obtaining a
waiver) by December 31.1995, which is
•vhe end of the first compliance period. It
• possible that this change may delay
mons:orui>' for some large systems, but
otherwise all monitoring in this rule will
be completed approximately five years
after promulgation rather than the tour
and one-half years in the May 22.1989
proposal. Most systems will monitor
sooner because today's rule does not
delay completion of initial monitoring .
for the smallest systems (those less than
3.300) for four and one-half years.
Systems serving less than 3.300 persons
constitute approximately 80 percent of
the regulated systems. Instead, under
today's nile. EPA is requiring the States
to establish a sampling schedule that
will result in approximately one-third of
the systems monitoring during each of
the three years of a compliance period.
States will have the flexibility to
designate which systems must monitor
each year based upon criteria such as
system size, vulnerability, geographic
location, and laboratory access. This
change will result in earlier completion
of initial monitoring for most systems.
EPA believes that allowing States the
discretion to schedule monitoring for
each system during the compliance
monitoring period will enable States to
manage their drinking water programs
more efficiently.
In cases where the State has not
adopted regulations by January 1.1993.
and in States and on Indian lands where
EPA retains primary enforcement .
responsibility, systems will be required
to complete monitoring within 12 months
after notification by EPA. In cases
where States have not yet adopted
regulations and EPA is the primacy
agent for this regulation. EPA intends to
use the priority scheme envisioned by
the State to minimize the disruption to
the regulated community when the State
does adopt the requirements and
schedules systems to monitor.
Once a system is scheduled for the
first, second, or third year of a
compliance period, the repeat schedule
is set for future compliance periods. For
example, if a system is scheduled by the
State to complete the initial base
requirement by the end of the first year.
all subsequent repeat base monitoring
for that system must be completed by
the end of the first year in the
appropriate three-year compliance
period. This is necessary to prevent
systems from monitoring in the first.year
of the first compliance period and the
third year of the repeat base period.
4. Monitoring Frequencies
a. Inorganics (1) Initial and Repeat
Base Requirements. In the May 1989
proposal, surface water systems were
required to monitor annually and
groundwater systems every three years.
Most commenters supported that
frequency. The monitoring frequencies
1991 / Rules and Regulations
in today's rule are identical to these
proposed frequencies. Systems will be
required to take the initial base sample
for each inorganic during the initial
compliance period of 1993 to 1995
(subject to State scheduling). Surface
water systems on annual sampling
schedule are required to start in 1993.
(2) Increased Monitoring. EPA has
added a requirement that systems that
exceed the MCL (either in a single
sample or with the average of me
original and repeat sample) and which.
consequently, are out of compliance.
must immediately (i.e.. the next calendar
quarter after the sample was taken)
begin monitoring quarterly. Systems
must continue to monitor quarterly until
the primacy agent determines that the
system is "reliably and consistently
below the MCL. Groundwater systems
must take a minimum of two samples
and surface water systems must take a
minimum of four samples after the last
analytical result above the MCL. beiore
the State can reduce monitoring
frequencies back to the base
requirement (i.e.. annually for surface
systems and every three years for
groundwater systems).
EPA is promulgating this change for
several reasons. First, it is consistent
with the monitoring requirements
contained elsewhere in this rule that
more frequent monitoring occur m
instances of non-compliance. Second.
EPA believes that systems that are out
of compliance should monitor more
frequently to determine the extent of the
problem. If EPA had not made this
change, groundwater systems that
exceed the MCL could continue to
monitor ev ry three yean. EPA believes
the previous frequencies for ground and
surface systems were not protective of
public health in those cases where
systems exceeded the MCL.
{31 Decreased Monitoring. In the May
1989 Notice. EPA proposed that systems
be allowed to reduce the morutonng
frequency to no less than 10 years
provided . sytem had Piously taken
Uiree samples that were all less than 50
percent of the MCL. States should base
Self decision on prior analytical results.
variation in analytical results, and
system changes such as pumping rates
or stream flows/characteristics.
EPA receives numerous comments on
the 50 percent trigger for reduced
monitoring with most commenters
opposing!* 50 percent trigger, calling it
arbitrary and with no health
significance. Other conunent"!l r
Rested that the 50 Pj^ent tngger
wTuld result in a pseudo MCL. After
reviewing the comment* EPA hat
decidedto eliminate the 50 percent
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Federal Register / Vol. 56. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations 3565
trigger and change the requirement to
three previous compliance samples
(including one that was taken after
January 1,1990) that are "reliably and
consistently" less than the MCL to give
the States additional flexibility to decide
which systems are eligible for reduced
monitoring. Systems meeting this
criterion are eligible for reduced
monitoring (e.g., a waiver).
Most commenters supported the 10-
> ear time frame as a reasonable.
monitoring frequency for reduced
monitoring. Because EPA is adopting a
3/0/9 compliance cycle, EPA is changing
the maximum reduced monitoring
frequency from the proposed 10 years to
9 years to gain consistency in its
regulations. EPA believes this change
will have a minimal impact on systems.
EPA is requiring one of the three
previous samples to be taken since
January 1,1990. The other two samples
could be taken at any time after June 24,
1977 when monitoring for inorganics
started. Because the reduction in
monitoring to every nine years begins in
the 1993-2001 compliance cycle, EPA
believes that one sample must be recent
(i.e., taken after January 1,1990) to
preclude unduly long time frames
occurring between samples. Systems
receiving a waiver may monitor at any
time during the nine-year compliance
cycle, as designated by the State.
EPA believes that systems should use
the same criteria outlined in the
preamble of the proposal (as modified
above) to reduce monitoring. Several
commenters suggest that systems that
meet the criteria automatically qualify
for a waiver without State approval.
EPA has rejected this approach because
it believes that State approval is crucial
in certain circumstances such as where
the system is adjacent to a toxic waste
site or other anthropogenic sources of
contamination. EPA anticipates that in
most cases, States will grant waivers
expeditiously.
b. Asbestos—(1) Initial *nd Repeat
Base Requirements. In the proposal,
systems were not required to monitor for
asbestos unless the State determined
that the system was vulnerable to
contamination within 18 months of
promulgation. If vulnerable, systems
were required to take one sample within
five years of promulgation. EPA also
proposed an alternative approach
requiring all systems to monitor unless
the system conducted a vulnerability
assessment and the State determined
the system was not vulnerable to
asbestos contamination.
Most commenters supported,the
propo*ed approach, although several
commenter* suggested that the
s.'temetive approach was preferable.
EPA, in today's rule, is promulgating the
alternative approach, which requires all
systems to monitor for asbestos during
the 1993 to 1995 compliance period. This
approach, as discussed previously,
results in an enforceable requirement,
but the number of systems judged to be
vulnerable should be the same as with
the proposal, provided vulnerability
assessments are conducted.
The base repeat frequency is once in
the first three-year monitoring period of
each nine-year cycle, v. hich means that
after the initial base monitoring
requirement is completed, systems
would not be required to monitor again
until the 2002 to 2005 compliance period.
EPA has not eliminated the repeat base
requirement because of concern that
there may be occurrence in a limited
number of systems. Systems that are not
vulnerable would continue to be eligible
to receive waivers. EPA is requiring
infrequent base monitoring requirements
because of the low probability of
occurrence, the limited analytic
capabilities to measure asbestos, and
the high analytical costs, and because of
regulatory activities such as the
corrosion control activities and '
asbestos/cement pipe ban, which EPA
.believes will reduce the future
occurrence of this contaminant.
(2) Increased Monitoring. In the May
1989 proposal, ground and surface water
systems exceeding 50 percent of the
MCL in the initial sample were required
to monitor every three years and
annually, respectively^ Several
commenters suggested that the source of
the water was not a valid criterion for
determining repeat monitoring
frequencies. EPA agrees and has
modified the n:ie as described below to
use the analytical result as the "trigger"
for any repeat monitoring.
Most comments on the asbestos
monitoring frequencies were in response
Ui the 50 percent trigger for repeat
mi. nitoring. For the reasons discussed
earlier, EPA has decided to eliminate
the 50 percent trigger and use the MCL
•to determine repeat monitoring
frequencies. EPA is prescribing the
"baseline" approach described above
for inorganics. Systems that exceed the
MCL must initiate quarterly monitoring
in the next calendar quarter. When the
State determines that the system is
"reliably and consistently" less than the
MCL (a minimum of two samples for
ground water and four for surface
water), then the system can reduce its
monitoring frequency to that set by the
State but not less than the base
requirement.
(3) Decreased Monitoring. Today's
rule allows States to grant waivers
based on a vulnerability assessment by
systems that considers contamination in
the raw water supply and/or from the
corrosion of asbestos/cement pipe
(including pipe tapping and repair) in .
the distribution system. Systems not
receiving a waiver must monitor at the
base frequency. Because monitoring is
not required in the second and third
three-year periods, no waiver is needed
in those monitoring periods.
Most commenters agreed with EPA's
criteria for reducing monitoring.
Consequently, the requirements are
promulgated as proposed.
c. tfitrate [I] Initial and Repeat Base
Requirements.—(A) Community and
Non-Transient Water Systems. The
proposed rule required ground and
surface water systems to monitor at
annual and quarterly intervals,
respectively. Commenters were mixed in
both supporting and opposing the
increased frequency compared to the
current requirements. Many commenters
said that although nitrate occurrence
was widespread, nitrate levels over time
were steady. After reviewing the
comments and reviewing occurrence
data, EPA is convinced that nitrate
occurrence is widespread and often has
seasonal fluctuations resulting from
factors such as when fertilizer is applied
and rainfall events. Consequently. EPA
believes nitrate monitoring frequencies
should be increased, as proposed, to
protect against the acute effect of
methemoglobinemia. Therefore, today's
rule retains the requirements as
proposed. Under today's rule,
monitoring for surface water systems
will begin in the first quarter of 1993;
CWS and NTWS groundwater systems
and transient non-community systems
(TWSs) must take one sample annually
beginning in 1993.
The proposed rule required systems to
monitor at the time of highest
vulnerability, which most commenters
suggested they were unable to
determine. Since EPA agrees that
determinning the time of highest
' vulnerability is difficult, tha Agency has
decided to change the time when
monitoring must be conducted. When a
system changes its monitoring frequency
from quarterly to annually, the annual
sample must be taken in the calendar
quarters) that previously yielded the
highest previous analytical result. For
example, if a system sampled in the
first, second, third, and fourth quarters
in the previous year and the analytical
results were 1 mg/1. 3 mg/1, 4 mg/1, and
2 mg/1, respectively, the system-is
required to take its annual sample in the
third quarter in the next year. Today's
rule considers the third quarter the time
of "highest vulnerability" for the
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3568 Federal Register / Vol. 56. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations
(B) Transient Non-Community Water
Systems. The proposed rule required
ground and surface water systems to
monitor at three- and one-year intervals.
In the proposal. EPA requested comment
en the frequency of monitoring
requirements for transient system. Most
commenters supported the proposed
frequencies: however, several .
commenters suggested that additional
monitoring was appropriate since nitrate
ia regulated as an acute toxin.
EPA now believes that a monitoring
frequency of every three years is not
protective of health for nitrate, an acute
toxin which is ubiquitous. Based on a
review of the comments, EPA has
decided to require all TWS systems
(including groundwater systems) to
monitor annually. Because analysis of
nitrate is relatively inexpensive and a
sample can be taken at the time the
system takes a colifonn sample, EPA
believes the impact of this change on
TWS will be minimal yet offer greater
health protection. Consequently. EPA is
promulgating annual sampling for
groundwater systems.
(2) Increased Monitoring (CWS,
NTWS, TWS). The proposed rule
required groundwater CWSs and
NTWSs to monitor at quarterly
frequencies when the concentration is
greater than 50 percent of the MCL for
dny one sample. The sampling frequency
remains quarterly until four consecutive
samples are less than 50 percent of the
MCL. As discussed earlier, most
commenters suggested deleting the 50
percent trigger for increased or
decreased monitoring. Even though
elsewhere in this rule the 50 percent
digger is eliminated. EPA has decided to
retain the 50 percent trigger for
increased nitrate monitoring in the case
of nitrate and also to extend this
requirement to TWSs. For this
contaminant. EPA believes the 50
percent trigger constitutes an early
warning signal for an acute
contaminant. Although EPA considered
other options as triggers for increased
monitoring, such as the level of
detection or the MCL, EPA believes
these are not appropriate both because
nitrate can be detected at levels far
below the MCL and because the MCL
represent* the level where above this
level acute effects may occur in some
individual. Consequently, EPA believes
that 5 mg/1 remains the best trigger for
increased nitrate monitoring. EPA
believe! that it is appropriate to extend
the increased monitoring frequencies to
induce transient water systems because
of 'J;e acute hazard po*ed by this
contaminant
EPA has decided to modify the
requirement for decreased monitoring.
In today's rule, a sys'tem that exceeds 50
percent of the MCL in any sample must
remain on a quarterly monitoring
schedule until a minimum of four
consecutive samples are judged by the
State to be "reliably and consistently"
less than the MCL. EPA believes that
this change allows States the flexibUity
to reduce the monitoring for those
systems that, while they have detectable
nitrates, are very unlikely to exceed the
MCL until the next monitoring cycle.
(3) Decreased Monitoring (Surface
CWS and NTWS). The proposed base
monitoring requirement for surface
water systems was quarterly. A
reduction to annual sampling was
permitted when four consecutive
sample* were less than 50 percent of the
MCL For the reasons explained above.
EPA has decided to change the proposal
somewhat to allow surface water
systems to decrease to an annual
frequency provided four consecutive
samples are "reliably and consistently"
less than the MCL
d. Nitrite (\) Initial and Repeat Base
Requirements. In the proposal, systems
were required to monitor for nitrite at
the same frequencies as for nitrate.
After reviewing comments and
reexamining limited occurrence
information (i.e.. State of Wisconsin.
Public Water Supply Data. 1970), which
indicates occurrence above 50 percent of
the MCL was very infrequent, EPA has
decided to require all systems to
monitor once for nitrite in the first
compliance period (1993 to 1995). If the
analytical result is less than 50 percent
of the MCL (0.5 mg/1), additional
. monitoring is at State discretion.
However, future measurements under
the nitrate requirement will mandate
combined measurement of nitrate plus
nitrite, both measured as nitrogen using
a single analytical technique.
If the analytical result in the initial
sample is equal to or greater than 50
percent of the MCL (i.e.. £0.5 nsg/1).
systems must then monitor quarterly
(with a rnir'"""" of four samples) until
the State determines that the system is
"reliably and consistently" less than the
MCL After that determination, systems
must monitor at an annual frequency.
e. Volatile Organic Contaminant*
(VOCs}—(I) Initial and Repeat Base
Requirements. In the VOC rule
promulgated in July 1987. EPA required
all systems to take four consecutive
quarterly samples. Groundwater
systems that conducted a vulnerability
assessment and were judged not
vulnerable, however, could stop
monitoring after the first sample
provided no VOCs were detected in that
initial sample. Repeat frequencies for all
systems vary by system size, detection.
and vulnerability status.
EPA has made several changes to the
proposed VOC requirements. EPA is
also today proposing to amend the July
1987 monitoring requirements for VOCs
to streamlining the requirements and to
make all VOC requirements consistent.
In the May 1969 notice and in the VOC
regulations promulgated in July 1987,
distinctions in base requirements were
made between ground and surface
water systems, less than and more than
500 service connections, and vulnerable
and non-vulnerable systems. EPA. in
streaming the requirements in today's
rule, will require all systems to take four
quarterly samples. Systems that do not
detect VOCs in the original round of
quarterly sampling are required to
monitor annually beginning In the next
calendar year after quarterly sampling is
completed. The State may allow
groundwater systems which conducted
three years of sampling and did not
detect VOCs to take a single sample
every three years. For example, systems
which complete quarterly monitoring in
calendar year 1993 are required to being
annual monitoring in 1994. EPA is
making thin change for several reasons.
First the occurrence of VOCs in
approximately 20 percent of systems
indicates that shortening the time frame
between when each sample is collected
for vulnerable groundwater systems
from every three to five years to an
annual sample is appropriate. Second.
the cost of analysis for VOCs has
decreased since the original proposal
Most VOC analyses now cost
approximately $150 per sample versus
the $200 per sample EPA estimated in .
the 1987 VOC rule. Trihalomethanes
(THMs) may also be measured in these
samples, thereby creating efficiencies
with current and future THM monitoring
requirements. Consequently, the
monitoring burden on most systems is
less than previously thought Third, most
commenters preferred annual
monitoring, stating that quarterly
monitoring presented managerial and
logistical problems. Where gr3~ndwater
systems have a demonstrated history of
non-detecU for VOCs, EPA believes a
reduction of monitoring to one sample
during each compliance period, if
allowed by the State, is protective of
health. For the above reasons, EPA is
promulgating the above monitoring
requirement changes.
In the May 1988 notice, EPA requested
comment on whether vulnerable
systems may take only one sample u no
VOCs are detected in the initial year of
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Federal Register / Vot. 56, No. 20 / Wednesday, January 30. 1991 / Rules and Regulations
356
monitoring. EPA's intent was to require
quarterly sampling in vulnerable
systems, but most commenters opposed
a change to more frequent monitoring.
Based on the comments received. EPA is
requiring vulnerable systems to take an
annual sample beginning in 1993
(instead of four quarterly samples) if no
VOCS were detected in the initial (ot:
subsequent) monitoring.
In today's rule. EPA is requiring
systems to conduct an initial round of
quarterly monitoring. In the 1987 VOC
rule, however. EPA required systems to
conduct unregulated contaminant
monitoring for all VOCs contained in
today's rule, and stated that those
results could be grandfathered in for .
future regulatory requirements.
Consequently. EPA will allow systems
that have conducted monitoring under
§ 141.40 to use those results to satisfy
the initial monitoring requirement for
those VOCs included in today's rule
even if a single sample, rather than four
quarterly samples, was taken. Only new
systems, existing systems with new
sampling points, or systems that did not
conduct monitoring under 5 141.40 prior
to December 31.1992, are required to
conduct initial base monitoring for the
VOCs in today's rule during the 1993-
1995 compliance period.
(2) Increased Monitoring. In the
proposal, systems detecting VOCS
idefined as any analytical result greater
than 0.0005 mg/1) were required to
monitor quarterly. In today's rule. EPA
is requiring systems that detect VOCs to
monitor quarterly until the State
determines that the system is "reliably
and consistently" below the MCL.
However, groundwater systems must
take a minimum of two samples and
surface water systems must take a
minimum of four samples before the
State may reduce the monitoring to the
base requirement ^i.e., annual sampling)
Systems remain on an annual
sampling frequency even if VOCs are
detected in subsequent samples, unless
an MCL is exceeded (or if the State
otherwise specifies). In this case, the
system returns to quarterly sampling in
the next calendar quarter until the State
determines that the new contamination
has decreased below the MCL and in
expected to remain reliably and
consistently below the MCL. This
determination shall again require a
minimum of four quarterly samples for
surface water systems and two
quarterly samples for groundwater
systems.
EIPA is making this change because
some systems may detec. VOCs at a
level slightly above the detection limi.
EIPA believes that where the State can
determine that contaminations
"reliably and consistently" less than the
MCL. those systems should be able to
return to the base monitoring
requirement (i.e.. annually). Giving .
States the discretion to determine
whether systems meet this criterion may
allow States to give monitoring relief to
some systems.
(3) Decreased Monitoring. States may
grant waivers to systems that are not
vulnerable and did not detect VOCs
while conducting base monitoring.
Vulnerability must be determined using
the criteria specified above in the •
discussion of vulnerability assessments.
EPA anticipates that most systems will
not be able to qualify for a "use" waiver
because of the ubiquity of VOCs.
However, systems conducting an
assessment that considers prior
occurrence and vulnerability
assessments (including those of
surrounding systems), environmental
persistence and transport, source
protection. Wellhead Protection
Assessments, and proximity to sources
of contamination may apply to the State
for a "susceptibility" waiver. If the
waiver is granted, systems are required
to take one sample and update the
current vulnerability assessment during
two consecutive compliance periods
(i.e.. six years). The vulnerability
assessment update must be completed
by the beginning of the second '
compliance period. EPA is increasing
the time frame from five to six years to
bring the five-year monitoring frequency
in the proposal in line with the 3/6/9/-
year frequencies specified in the
standard monitoring framework.
EPA proposed that States have the
discretion to set subsequent frequencies
in systems that di'd not detect VOCs in
the initial round of four iquarterly
samples and that are designated as not
vulnerable based on assessment. Most
commenters supported this provision,
and it is promulgated as proposed. The
repeat monitoring frequency for
groundwater systems meeting this
criteria shall be not less than one
sample every six years as discussed"
above. For surface water systems
meeting thij criteria the repeat
frequency is at State discretion.
/. Pesticides/PCBs—(1) Initial and
Repeat Base Requirements. In the May
1989 proposal, systems were not
required to monitor unless the State, on
the basis of a vulnerability assessment.
determined the system vulnerable. If
vulnerable, systems were required to
take four consecutive quarterly samples.
EPA requested comment on an
alternative approach that would require
all systems Jo monitor for all
contaminants. As discussed above,
today's requirements specify that all.
systems must take four quarterly
samples every three years. However, a!
systems are eligible for waivers from U
quarterly monitoring requirement, as
discussed in the section on decreased
monitoring below.
Most comments on the proposal
revolved around two issues—the'
requirement that systems monitor .
quarterly and the requirement that all
systems monitor at the time of highest
vulnerability. Many commenters stated
that quarterly monitoring was not
necessary to detect changes in
contamination. Many commenters
recommended annual monitoring for
pesticides. After reviewing the
information and comments submitted..
EPA believes that quarterly monitoring
remains the best scheme to determine
contamination. Occurrence informatior
available to EPA indicates that season
fluctuations from runoff and
applications of pesticides may occur;
thus, quarterly monitoring is better thai
annual monitoring to determine
pesticide contamination. In some cases
it may be appropriate to monitor at
greater frequencies than those specifiec
by today's rule to better determine
exposure. States and systems have the
option to monitor at greater frequencies
than the federal minimuma.
Most commenters opposed the
requirement to monitor at the time of
highest vulnerability, stating that highe:
vulnerability cannot be predicted or
determined. Several commenters stated
that the requirement to monitor at the
. time of highest vulnerability was
unenforceable. EPA agrees and
. eliminates this requirement from today'
rule. However. States are advised to
examine sampling practices of systems
to assure that periods of likely
contamination are not avoided. This is
especially true for surface water
systems monitoring for pesticides after
rainfall and/or application of pesticide:
.In the May 1989 notice, EPA proposec
that systems conduct repeat monitoring
every three or five years, depending on
system size and ground/surface
distinctions. In today's rule, the repeat
monitoring frequency for all systems is,
four consecutive quarterly samples eac
compliance period. However, EPA has
made several adjustments for systems
that do not detect contamination in the
initial compliance period. After the
initial monitoring round is completed.
systems that serve >3.300 persons may
reduce the sampling frequency to two
samples in one year during each
compliance period. Systems serving
<3,300 person* may reduce the
sampling frequency to one sample. EPA
has increased the frequency small
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3568 Federal Regiflter / V9I. 56. No. 20 / Wednesday. January 30. 199? / Rules and Regulations -.
systems must monitor in this rule from
evtry five yean to every three yean,
because EPA believe* that this change
will offer greater health protection. EPA
believes that every aix year* ia too long
an interval to determine changes in
consumer expoiure. In addition, because
EPA has coupled this change with
revised procedure* for granting "use"
waiver*, the impact of this change will
be minimal-
EPA has made the granting of "use"
waivers for pesticides easier in this rule
and will permit States to grant "area
wide" or "Statewide" waivers based
upon pestidda use information. EPA
anticipates in adopting this schema,
along with the other change* outlined in
today's rula. that many systems will b«
able to obtain a "use" waiver. For those
systems not able to obtain a waiver (i.e.,
vulnerable systems). EPA believes it is
appropriate to monitor at three-year ,
intervals to determine contamination.
(Z) Increased Monitoring. In the May
1989 notice, systems with less than SOO
service connections that detect
contamination were required to monitor
annually. Systems with more than 500
service connections that detect
pesticides are required to monitor
quarterly. EPA defined detection as
greater than 50 percent of the MCL.
Most comments revolved around the 50
percent trigger. As discussed above,
EPA is redefining detection for
pesticides to mean using the method
detection limit (see table 24). EPA
believes it is appropriate to use the
method detection limit as the trigger for
reduced monitoring because detection
implies that a pathway to contamination
exists. Consequently, additional
monitoring is required to determine the
extent and variability of pesticide
contamination. In today's rule, all
systems that detect pesticides/PCBs
must monitor quarterly until a reliable
baseline has been established.
TABLE 24.—METHOD DETECTIO* LJMTTS—
. PesnaDES/PCBs ,
TABLE 24.—METHOD DETECTION LIMITS—
PESTCIOES/PCBS—Continued
ContvnnjrK
AJdcarb ,_.................—...-••• ••
AV*"tti mf^rrm . ..
Atntarx .....
C«rt>ofcr»n
CTtfcicd^n . —
EPMO-*: tsuforeii*! (Eoe;
a*K*on Pratt
0.0032810/1
0 0005 mg/l
0,0006 mg/l
0,0008(09/1
O.OCO1 mg/l
0.0008 mg/i
0.002 m»/l
0,00002 mo/1
0.0001 ing/I
0.00001 me"
ODOOO4 me/I
O.OOCO2 mB/1
0.0002 m»/l
0-DQCl ae/l
Cantvww*
D'si_*-(^rM4^< f^fianuta (PCBs)
P«nuchtoroph«r>ot -
Toxaphcn* — — — - —
2.4.5-TP (SN«K)...".-
MKSonfci*
0 0001 mg/l
0.00001 mo/I
0.001 mg/l
0.0002 mg/l
As described previously, upon
detection, all systems must immediately
begin quarterly monitoring. The Stata
may reduce the system to annual
monitoring after determining it ia
"reliably and consistently" below the
MCL. A reduction to annual monitoring
may occur after a tnif'""'m of two
samples for groundwater and fovr
samples for surface water systems.
After three years of annual monitoring
which remains "reliably and
consistently" below the MCL. systems
can return to the base monitoring
requirement (i.e, four quarterly sample*
every three years).
(3) Decreased Monitoring. Systems
that obtain a waiver from th° monitoring
requirements are not required to
monitor. All systems are eligible for
waivers in the first three-year
compliance period of 1963 to 1995. As
discussed above. EPA has simplified the
vulnerability assessment procedure* by
allowing the system to assess whether
the contaminant has been used.
transported, mixed, or stored in the
watershed or tone of influence. Where
previous pesticide/PCB use in the area
can be ruled out. system* may apply to
the State for a u«e waiver. EPA1* intent
in promulgating this change i* to make it
easier for systems to obtain waivers in
those situation* where the chemical has
not been used. State* may be able to
determine that the entire State or
specific geographic areas of the State
have not used the contaminant and
consequently granted "area wide"
waivers. £y*tem* that cannot determine
use may still qualify for a waiver by
evaluating susceptibility according to
the criteria discussed in the VOC
section above. Waivers must be
renewed every three year*.
EPA requested comments on whether
system* that did not detect canceled
pesticides in the initial monitoring round
should be presumed to be non-
vulnerablB and therefore not required to
monitor. After reviewing the ooramenti
and information on illegal pesticide use,
EPA continues to believe that no
occurrence improves the likelihood that
the State will grant a waiver from
continued monitoring of a canceled
pesticide. Due to possible persistence in
the environment however, EPA does not
agree with commenter* who believe that
waivers should be granted
automatically.
5. Other Issue*
a. Compliance Determinations.
Several commenters suggested that, for
a compliance determination, a single
sample or four quarterly samples are not
representative of water delivered tc
consumers. Several commenters
suggested that EPA adopt an averaging
period of longer than one year for
compounds posing chronic health
hazards. EPA continues to believe that
any excursion above an MCL presents a
risk to health and should be addressed
immediately. Howe /er. in a practical
sense, most systems would not
immediately install treatment until
establishing a baseline based on
additional mftnit"ring to determine (he
extent of the problem. Several years will
elapse after a violation before treatment
is installed. Consequently, the concern
of the commenter that a single sample
may result in treatment is unfounded.
EPA wishes to point out that water
system* can always submit a sampling
plan (subject to State approval) that
include* more monitoring than the
minimum established by EPA. if that
will result hi« better representative
sample.
Several commenter* opposed the
proposed requirement that a *ystem i*
immediately out of compliance and must
give public notice if the initial or the
total of subsequent samples is more
than four time* the MCL. The
commenter* were concerned that non-
compliance may be based on a »ingle
sample. EPA point* out that .any
quarterly sample that exceeds the MCL
by four times would result to an annual
average that exceed* the MCL EPA
continue* to believe that thi* approach
gives early warning to consumers that a
health problem may exist EPA has
clarified how the annual average is
calculated by specifying that any
analyses below the detection limit shall
be calculated as zero.
Several commenter* opposed the
requirement that if a *ingls sampling
point i* out of compliance, then the
entire «ystem i* out of compliance. A*
previously *tatedL EPA has adopted thi*
policy because EPA determine* system
compliance, not sampling point
compliance.
EPA wishes to point out and clariry
that once a system is waived from
specific meatorement of nitrite, as
discussed above, compliance will be
determined through a measurement of
combined nitrate and nitrate (measured
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Federal Register / Vol. 56, No. 20 / Wednesday. January 30, 1991 / Rules and Regulations 356
as N). The MCL for this combined
measurement remain* at 10 mg/1 as N.
b. Confirmation Samples. EPA
proposed that if an analytical result
greater than 10 mg/1 for nitrate and l
mg/1 for nitrate indicates that the
system may exceed the MCL, then that
system must take a confirmation sample
within 24 hours of notification of the
analytical result. Results from both
samples must be reported to the State
within two weeks of the date the initial
sample was taken. Most cemmentera
opposed the requirement to take a
confirmation sample within 24 hours of
notification, stating that it was
impractical to require a system to
monitor that quickly. EPA agrees with
the commenters and has modified
today's rule to allow systems in which
the first sample exceeds the MCL to
notify the public within 24 hours of .
receipt of the analytical results through
posting, mail notification, or radio/TV
that the system may be in violation. If
the system decides to take this option,
then it must take a confirmation sample
within two weeks of the original
notification.
c. Compositing. In the May 1989
proposal EPA allowed systems, at the
discretion of the State, to composite up
to five samples. Compositing must be
done in the laboratory. Most
commenters supported compositing as a
methodology to cut costs. In this final
rule, EPA is limiting compositing among
different systems to only those systems
serving fewer than 3.300 people.
Systems serving greater than 3,300
persons will be allowed to composite
but only within their own system. EPA
also requested comments on whether
State discretion on compositing is
necessary or whether systems can
composite automatically without State
approval. Several States opposed this
change; consequently, the final rule is
unchanged from the proposal. EPA
believes that compositing is- to be used .
only when cost savings are important
and systems alone should not make that
determination.
d. Asbestos. Some commenters were
confused by the wording used to tpecify
sampling points in a die-.ibution system
for measuring asbestos when a system
or part of a system is judged vulnerable.
EPA wishes to clarify that collecting a
sample at a consumer tap is not
necessary. It is sufficient to collect at a
convenient place in those parts of the
distribution system that have been
deemed vulnerable to asbestos
contamination.
6. Unregulated Contaminant Monitoring
EPA proposed requirements to
monitor for other "unregulated"
contaminants. "Unregulated"
contaminants are those contaminants
for which EPA establishes a monitoring
requirement but which do not have an
associated MCLG, MCL or treatment
technique (see table 25). EPA may
regulate these contaminants in the
future.
TABLE 25.—UNREGULATED INORGANIC
AND ORGANIC CONTAMINANTS
EPA «n*lyt>c*) method
Organic contaminants
Aldnn ............................ . ......
B«nzo(i)pyr*no .................
Butuchlor ............................
Cartoaryl ..............................
Dalopon ........ . .....................
»-2(«tfiy1h«!
2(ethylh«xyOphthalat«».
Ocumtoa .............................
Dino««b
Oqu«t
Endothafl
Glyphosat* ..... .
HcxacMorotMnzarw .
Hexachtorocyctopanta-
3-Hydroxycartxsfuran
MatotecWor ......... . ..............
M«trt>UDn ....................... ....
Oxamyl (vydate) ............. ...
Propachkx .........................
Simnzin* .............................
2.3.7.S-TCOO (Dionn) .......
Inorganc contaminants
Anttmom/ ..................... . .....
Borytiiunr.
Sutfata....
Tfuflium..
Cyand*
SOS. 506, 525
525. 550, 550.1
507. 525
531.1
515.1
506. 525
SOS. 525
515.1
SOS, 506, 525
olS.1
540
548
547
SOS, SOS. 525
505.525
531.1
531.1
507, 525
507. 508. 525
531.1
515.1
507, 525
505, 507, 525
513
Graphite Fumac* Atomic
Abaorpttan; Inductivaty
Couptad Plasma.
Graphiaa Fwnaoa Atomic
Abaorption; InducUvafy •
Couptad Maaa
Spactromaey Plasm*;
Spactrophotomatrte.
Atomic Abaorppon;
InducOnty Couptod
Ptaona; Graph**
Furnaoa Atomic
Absorption.
Cohmbnatilc.
Graphite Fumac* Atomic
Abtotpten. InductNMy
CouptodMaM
Spociromatry Plaama.
S(/«clropftotG
-------
3570
Federal Rayrtef / Vol. 56. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations
The SDWA require* that variance* may
only be granted to those systems that
have installed BAT (as identified by
EPA). However, in limited situations a
system may receive a variance if it
demonstrates that the BAT would only
achieve a de minimus reduction in
contamination (see § 142.62(d)). Before
EPA or a State issues a variance, it must
find that the variance will not result in
an unreasonable risk to health.
Under section-1413(a)(4) of the Act. .
States with primacy that choose to issue
variances must do so under condition*
and in a manner that is no less stringent
than EPA allows under section 1415.
Before a State may issue a variance, it
must find that the system is unable to (1)
join another water system, or (2)
develop another source of water and
thus comply fully with all applicable
drinking water regulations.
The Act permits EPA to vary the BAT
established under section 1415 from that
established under section 1412 based on
a number of findings such as system
size, physical conditions related to
engineering feasibility, and the cost of
compliance. Paragraph 142.62 of this rule
lists the BAT that EPA has specified
under section 1415 of the Act for the
purpose* of issuing variance*. This list
mirror* the proposed list except that
electrodialysis is considered BAT for
barium, nitrate, and selenium as
discussed in "Selection of Be*t
Available Technology" above.
EPA received several comments on its
proposed list of section 1415 BAT. The
commenters agreed wim EPA that
coagulation/filtration and lime softening
should be excluded a* BAT for those
systems serving <500 service.
connections. In the proposal EPA
requested comment on whether reverse
osmosis, activated alumina, and ion
exchange should be considered BAT for
small systems because of the relatively
high costs of these technologies. EPA
also stated that it was continuing to
evaluate what costs are feasible for
public water systems and that it was
currently examining alternative
affordability cntera. EPA also
requested comments on whether PTA.
should be BAT for DBCP and EDB
because of high air-to-water ratio*
resulting in increased costs.
In the proposal. EPA based its cost
estimate* on designs reflecting best
engineering practice. Some of the
assumptions underlying these cost
estimates may be unreelistic,
considering lie nature of small water
systems and their ability to procure,
finance, or operate facilities. In other
ca'scn. the assumptions cud not reflect
EP.-\ * best understanding of design and
average Qows in water systems, the cost
of waste treatment, or the cost* of
engineering more likely to be used by
small water systems. A reexamination
of these assumptions has led EPA to
conclude that the costs of treatment to a
water system and its customers may He
within a very wide range depending on
site-specific conditions md
requirements.
EPA has produced a draft report
entitled "Small System Technology Cost
Revisions" (U.S. EPA, Office of Drinking
Water. May 1990), which describes the
cost of treatment trains that are more
likely to be used in small water systems.
The costs in that report are baaed on
engineering assumption* different from
those used to cost very small system
technologies at the time of the proposal.
Differences between engineering
assumptions and those used in the
proposal include, for example, purchase
of prebuilt sheds rather than full
construction of a shed,
Cost estimates in the "Small System
Technology Cost Revision*" draft report
of technologies with contaminant
removal capability equivalent to those
discussed in the proposal are
significantly lower. For example, the
cost of removing chromium using two-
bed ion exchange treatment in a water ,
system serving 25-100 people was listed
in the proposal at $3.40/1.000 gallons. As
a result of updating flow and waste
disposal assumptions, the cost is now
estimated at S10.16/1.000 gallons. This i*
equivalent to about $1.000 per year per
household served by the water system.
In the draft report the co«t of using ion
exchange treatment (as described in the
May 1980 draft report) is only $0.91 / .
1,000 gallon*, or about $90 per year per
household in mis size water system.
assuming no need for off-site waste
disposal If off-site waste disposal is
necessary, coat* per household might
grow to about $200-$300/yr, «till
significantly less than the $l,000/yr
associated with more expensive
engineering assumptions.
EPA recon?izes that its May report is
not only a draft, but also only a
preliminary investigation into the actual
cost* likely to be incurred by very small
water system*. The report, however,
confirms substantial anecdotal evidence
that EPA's previou* small system* cost*
may be overestimated in some
circumstances. A* a reault of thi*
revaluation of coating assumptions,
EPA concludes that low-co*t treatment
train* using the section 1415
technologies could be affordable.
Therefore, EPA finds that all
technologies a* liated in tables 28 and 27
are section 1415 BAT.
2. Point-of-Use Devices. Bottled Water
and Point-of-Entry Devices
Under section 1415(a) of the SDWA.
when the State grants a variance or
exemption, it must prescribe an
implementation schedule and any
additional control measure* that the
system must take. States may require
the use of point-of-use (POU) devices,
bottled water, and other mitigating
device* as "additional" control
measures if an "unreasonable risk to
health exists." One commenter stated
that EPA should also include point-of-
entry (POE) devices as an additional
option. EPA agrees and has amended
S i 142.57 vd 142.02 in today'* rule to
allow POE«? :vices as an interim control
measure while a variance or exemption
is in effect Public water systems may
also use POE devices for full compliance
with the MCLs if they meet certain
criteria and procedures specified in 40
CFR f 141.100.
3. Exemption!)
Under section 1416{a), a State or EPA
may grant an exemption extending
deadlines for compliance with a
treatment technique or MCL if it find*
that (1) due to compelling factors (which
may inlcude economic factors), the PWS
is unable to comply with the
requirement (2) the exemption will not
result in an unreasonable risk to human
health; and (3) the system was in
operation on me effective date of the
NPDWR, or, for a system not in
operation on that date, no reasonable
alternative source of drinking water is
available to the new system.
In determining whether to grant an .
exemption. EPA expects the State to
determine whether the facility could be
consolidated with another system or
whether an alternative source could be
developed. Another compelling factor is
the affordability of the required
treatments. It is possible mat very small
systems may not be able to consolidate
or find a low-cost treatment. EPA
anticipates that States may wish to
consider granting an exemption when
the requisite treatment is not affordable.
EPA believes that as a rule of thumb,
a total annual household water bill
becomes unaffordable when it is greater
than 2 percent of the median household
income, or about $650/household/year.
if calculated based on median national
income. EPA realises that affordability
cannot be characterized by a single
threshold, and believes that in cases
where local median income is very low.
a total annual household water bill as
small as $450 may be on affordable. EPA
-------
Federal Register / Vol. 55. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations 337
believes that any total annual bills
below that amount are affordable.
EPA considered a wide variety of
information when formulating this
unaffordability rule of-thumb. Today, the
average annual household water bill is
about S250. To supplement centrally
treated and piped water with bottled
water costs about $400 more-per year, a
cost many people throughout the nation
are willing to pay on an increasingly
frequent basis. This mirrors the market
costs of various POU and POE devices
intended to provide safe drinking water
and which now constitute an active
household products market. In addition.
EPA's rule of thumb is similar to that
used by the Department of Agriculture's
FannenT Home Administration (FmHA)
guidance on the use of grants in place of
loans, based on hardship. Finally, the 2
percent of median income, $650/yr,
value is about equal to the highest
existing annual water bills, although
abnormally high rates (greater than
$l,000/yr) have been documented in a
handful of communities. EPA believes
its rule of thumb reflects both what
many people consider affordable for
high quality water and established
federal policy with regard to enonomic
hardship.
When considering the appropriateness
of an exemption based on affordability,
the States should ensure that a full faith
effort has been made to consider low-
cost solutions similar to those examined
in the May 1990 draft EPA report
Several commenters also indicated
that affordability considerations should
include all treatments that might need to
be applied by a water system, not
merely those associated with this rule.
EPA agrees with these comments, and
expects States will review all. the
treatment requirements of water
- systems to add as many treatment
techniques as are affordable. Where the
total treatment need is not affordable,
those treatments should be required that
result in the greatest risk reduction.
while remaining affordable under the
criteria given above.
Under section 14ie{b)(2)(B) of the Act
an exemption may b* extended or
renewed (in the cases of systems that
serve less than 500 service connections
and that need financial assistance for
the necessary improvements) for one or
more two-year periods. EPA believes
that information on low-cost
technologies will receive a considerable
amount of attention over the next
several years and States giving
exemptions based on affordability
should be prepared to required small
water systems to regularly reex-smine
the available technologies to ensure that
any new low-cost opportunities are
applied, where appropriate.
TABLE 26.— SECTION 1415 BAT FOR
INORGANIC COMPOUNDS
Crwmcaf
Asbattos
Banum
Cadmium
Chromium
Marcurv .
Nitmt* „
Nitma
Safanum
BATi
2.3.8
5. 6. 7. 9
2. 5, 6, 7
2. 5, 6 «. 7
2 '. 4. e •.
7«
5.7.9
5.7
1. 2 ». 6. 7.
9
1 BAT orty if influent HQ coocantnoora ara OO
(jg/H.
• BAT for Chromium III only.
' ' BAT for Satarium IV only.
Key to BA Ts in Table 28
1 = Activated Alumine.
2 = Coagulation/Filtraaon (not BAT for
syttems with <500 service connections).
3 = Direct and Diatomite Filtration.
4 = Granular Activated Carbon.
5 = Ion Exchange.
6 = Lime Softening (not BAT for systems with
< 500 service connections). •
7= Reverse Osmosis.
8= Corrosion Control
9 = Electrodialysis.
TABLE 27.— SECTION 1415 BAT FOR
ORGANIC COMPOUNDS
Chemical name
Bonzttna
Carbon tatracfilonda
1.24>critoro«tfian«
Trichtoroathylaoe
para-Oichtoooaroana
1^-Ocr*X3«ttiy(«n«
1.1.1-Tncnloroatnana ,
Vinyi jSUonda ,
ca- 1 .2-OJHd uatt lylana
1 .2-OScttoropropana
Ethy1L»nzar»a
Moo6chtorob«r.zana
t> U vO*CfrfOrObW HWia
Styrana . . ..
T«tracNoro«tf»y*ona
Tofcjana ;.„.,
trana- 1 ,2-Oicnloroa
-------
3572
Federal Register / Vol. 56. No. 20 / Wednesday, knuary 30. 1991 / Rulea and Regulation^
append the notification to include
information on the nature, severity and
context of potential health effects, a*
well as other useful information. One
commenter stated that more detail arid
explanation is needed to define "little or
no. risk." which is the generic conclusion
of'each notification. Th's commenter
suggested that niore of the risk
assessment assumptions be included
(e.g.. lifetime consumption of 2 liters per
day with a x-feld safety factor]. One
commenter similarly felt some
Indication that a margin of safety is used
to establish MCLs is needed.
EPA Retponte. EPA believes the
public notification language Is
sufficiently detailed for the public and
should not be unnecessarily alarming.
Some language has been modified based
on the chemical-specific comments that
were received.
EPA believes that mandt lory
language is the most appropriate (if not
the only] way to inform the affected
public of the health implications of
violating a particular EPA standard. It is
appropriate for EPA to specify the
language because the Agency is familiar
with the specific health implications of
violating each standard which were
documented in the course of developing
the NPDWRs. EPA is aware that the
health implications of these violations of
vary in their magnitude. Public water
systems are free to make that point in
their public notices as long as the
mandatory language is included as welL
For instance, the system may want to
note that its violation is only slightly
above the standard. In fact, the public
water system or State may supplement
the notice as long as the notice informs
the public of the health risks which EPA
has associated with violation of th*
standards and the mandatory health
effects language remains Intact
EPA believes the public notifications
should be in non-technical terms.
Providing the specific risk assessment
assumptions or discussing the margin of
safety would be too detailed and raise
confusion.
2. Contaminant-Specific Comments
a. Asbestos. Four commenters stated
that the language for asbestos should
not state that the standard is based on
reducing cancer ri&fcs, since asbestos is
not a carcinogen. Two commenters
asked that the statement be revised to
separate the insulating and fire
retardant u*ea from A/C pipe use*. One
commenter suggested the following
modification for asbestos: "Ingestion of
asbestos n associated with polyps
,uen:gn tumors] In rats."
EPA R&sponsc. EPA agrees with most
«f the commenti received on asbestos
and has modified the public notification
language accordingly. The standard for
asbestos is based on reducing possible
human cancer risks from drinking water
exposure.
b. Other Contaminants. One
commenter stated that the language for
selenium should be revised to explain
the nutritional essentiality of selenium.
One commenter stated that the nitrate
language should state that alternate
water sources should be provided to
children under one year of age. One
commenter recommended modified
wording for styrene. One commenter
agreed with the notification language for
alachlor and monochlorobenzene. One
commenter recommended the following
replacement wording for pesticides:
"Under certain soil and climatic
conditions (e.g.. sandy soil and high
rainfall], substance 'X1 may leach into
ground water after normal agricultural
applications or may enter drinking
water supplies as a result of surface
runoff." One commenter believes the
statement concerning liver and kidney
effects from atrazine is an error. Thn
same commenter provided suggested
changes for 20 chemical*. One
commenter believes the cadmium
language. "Smoking of tobacco is a
common source of general exposure," is
inappropriate; this commenter believes
that the notifications should only
include information on occurrence or
exposure from drinking water. This
same commenter believes the language
for the polymers acrylamide and
epichlorohydrra is too alarming
considering the ™»n
-------
Federal Register / ^01. 56.'No. 20- / Wednesday. January 30. 1991 / Rules and Regulations 3573
analytical technology for possible
adoption in a proposed future secondary
regulation amendment. The task force
may also provide supplementary
guidance relating to detectable and
aesthetically displeasing levels for
specific organic chsmicals.
EPA wishes to alert the States.
utilities, and consumers that it is
retaining the existing odor SMCL of 3
Total Odor Number (TON) (see 40 CFR
143.3). Utilities are urged to find
imaginative ways to meet the objective
of having more pleasing odor
characteristics for their finished water
using the current 3 TON standard.
Where officials and consumers find
Contaminated drinking waters, they may
expect to detect (possib.y slight) tastes
or odors at the concentrd'.ions indicated
below:
o-Dichlorobenzene 0.01 mg/I.
p-Dichlorobenzene 0.005 mg/1,
Ethylbenzene 0.03 mg/1,
Pentachlorophenol 0.03 mg/1,
Styrene 0.01 mg/1.
Toluene 0.04 mg/1,
Xylene 0.02 mg/1.
2. Aluminum
A total of 17 individuals or
organizations provided comments in
response to the proposed SMCL of 0.05 •
mg/1 for aluminum. All of these
commenters agreed that the proposed
SMCL is too low and should either be
increased or eliminated.
Pertinent points from the comments
are summarized as follows:
• The American Water Works
Association (AWWA) no longer backs
the quality goal of 0.05 mg/1 which it
initially adopted on January 28, 1968 but
does support a "recommended operating
level of 0.2 mg/1."
• The proposed SMCL of 0.05 mg/1
would be very difficult for many utilities
to meet: a 1987 AWWA/Research
Foundation Survey of 90+ utilities
indicated an average aluminum
concentration of 0.09 mg/1 in finished'
water. Individual utilities also expressed
concern with difficulty in meeting the
0.05 mg/l SMCL.
• There is insufficient experimental
data to define the level at which an
aesthetic effect might occur in various
waters and treatments.
EPA believes that in some waters
post-precipitation of aluminum may take
place after treatment. This could cause
increased turbidity and aluminum water
quality slugs under certain treatment
and distribution changes.. EPA also
agrees with the World Health
Organization (WHO, 1984) that
"discoloration of drinking water in
distribution systems may occur when
the aluminum level exceeds 0.1 nig.'l in
the finished water." WHO further
adopts a guidance level of 0.2 mg/1 in
recognition of difficulty .n meeting the
lower level in some situations. While
EPA encourages utilities to. meet a level
of 0.05 rr.g/1 where possible, it still
believes that varying water quality and
treatment situations necessitate a
flexible approach to establish the SMCL.
What may be appropriate in one case
may not be appropriate in another.
Hence, a range for the standard is
appropriate. The definition of
"secondary drinking water regulation"
in the SOW A provides that variations
.nay be allowed according to "other
circumstances." The State primacy
agency may make a decision on the
appropriate level for each utility on a
case-by-case basis. Consequently, for
the reasons giv«?n above, the final SMCL
for aluminum will be a range of 0.05 mg/
1 to 0.2 mg/1, with the precise level then
being determined by the State for each
system.
3. Silver
On May 22.1989. EPA proposed to
delete the current MCL for silver (Ag),
because the only potential adverse
effect from exposure to silver in drinking
water is argyria (a discoloration of the
skin). EPA considers argyria a cosmetic
effect since it does not impair body
function. Also, silver is seldom found at
significant levels in water supplies and
drinking water has never been identified
as the cause of argyria in the United
States. While the health effects of silver
may only be cosmetic, many home
water treatment devices use silver as an
antibacterial agent. These devices may
present a potential contamination 'l-^eat
when used in a system. Therefore, EPA
proposed (54 FR 22062) an SMCL for
silver at 0.09 mg/1 based on the skin
' cosmetic effect called argyria. EPA also
asked the public to comment on the
selection of an uncertainty factor (UF) in
the alternate calculation of SMCL.
assuming an oral absorption factor of 4
percent.
Public Comments. A total of six
individuals or organizations provided
comments in response to the proposed
rule regarding silver. All commenters
agreed that the MCL for silver (0.05 mg/
1) should be deleted. Several
commenters agreed with EPA's proposal
of an SMCL for silver. Other
commented disagreed with this
proposal, citing the following reasons for
support:
• Silver does not affect the taste.
odor, color, or appearance of the
drinking water.
• There is no evidence that :hc iow
level of silver that might be found -n
drinking water causes argyria in
humar.s.
In response to a specific question
posed in the Federal Register Notice on
the selection of a UF for the altarnats
calculations of the SMCL. different
opinions were expressed. Several
comrrienters suggested using an
uncertainty factor of 2 in suFP°rt oi 25
mg/1). while one proposed to Keep ths»
SMCL at the current MCL of 0 05 mg/1.
EP.i Response. EPA has decided a
SMCL of O.1 mg/l is needed to protect
the general public from the cosmetic
effect of argyuria (from lifetime
exposure to silver). While the health
effects of silver may only be cosmetic.
many home water treatment devices 'jse
silver as an antibacterial agent, thus
presenting a potential contamination
threat when such devices are used in a
system. Therefore. EPA has decided lo
keep the SMCL at 0.1 mg/l to protect the
welfare of the general public from the
cosmetic effect of argyria.
EPA is proposing to use the same data
base as before to calculate the SMCL for
silver. Assuming 1 g of ailver by i.v. will
cause argyria in the most sensitive
individuals (Gaul and Staud, Am. Nted.
Assoc. 104:1387-1390.1935; Hill and
Pillsbury. 1939) and assuming an oral
' absorption rate of 4 percent (Fuchner et
a!.. Health Physics 15:505-514.1968), a
lifetime exposure of 70 years, and a UF
of 3. an SMCL of 0.1 mg/l is derived. For
more detail, see the following derivation
of SMCL
a. Derivation of SMCL for Silver. The
cosmetic DWEL is calculated assuming
1 g of silver administered i.v. will
produce a mild argyria in the most
sensitive individuals (Gaul and Staud.
1935; Hill and Pillsbury, 1939). Assuming
4 percent absorption of silver (Furchner
et al., 1968) following oral exposure, the
i.v. dose corresponds to an oral dose of
25 g (1 g/0.04 = 25 g). This dose is then
averaged over a lifetime assumed to be
70 years:
25gx
lifetime
• 25,550 days
= 978 jig/day
Based on an adult body weight of 70
kg, this corresponds to 14 jig kg/day
(978 fig/day / 70 kg = 14 ftg/kg/day).
Step 1-^Cosmetic RfD Derivation
-------
3574 Fedund Register
Vol. 56. No. 20 / Wednesday, January 30. 1991 / Rules and Regulation
Ccsmeuc
RfJ
where:
14 K* Ag'ks/day -Lewsi Goswved
Cosir.et.c Effect Le-.e: based on argyna.
3-uneerta.nty fac'.cr.
An uncertainty factor of 3 was applied
Icr Ihe following reasons. First, a 10-fold.
uncertainty factor is usually applied to •.
human data to account for ictraspecies
variability. However, since this
derivation has already included
sensitiva individual*, a ID-fold
uncertainty factor is not warranted.
Second, an uncertainty factor leas than
10 (i.e., 3) is sufficiently protective sinc&
the estimated dose causing argyria
within one to three years is being
apportioned over a lifetime. Finally, the
effect is based on argyria. which is
c Jnsidered a cosmetic effect and not an
adverse health effect.
Step 2—-Cosmetic DWEL Derivation
Coimedc DWEL
4.7 Mg Ag/kg/
dayxTO kg
2 I/day
. 16411.1/1 (rounded to
where:
4.7 fig Ag/kg/day - Cosmetic RfO.
70 kg — assumed body weight of »n adult.
2 l/d«y - «s«maed water conwiisption by an
adult.
The Cosmetic DWEL is derived on the
assumption that 100 percent of the silver
intake comes from drinking water. As
estimated by the World Heath
Organization (WHO. 1960). the upper
bound of intake level for silverfrotn
food is 20 to 60 fig per day; from air it i>
e?sentially negligible. Therefore^ the
SMCL for tko ccimetic effect of silver
ccn b« calculated by subtracting the
amount obtained in food.
Step 3—SMCL
(00047 mg/kg/
day) (70 kg7-0.06
SMCL - jug/day _
7 I/day
= 0.12 mg/1 (rounded '.3 0.1 mg/1 or 100 jig/
1)
/. State Implementation
• The Safe Drinking Water Act provides
that States mcy assume primary
implementation and enforcement
responsibilities. Fifry-foi • out of 57
jurisdictions have applied for end
received primary enforcement
responsibility (primacy) under the Act.
To implement the federal -egulations for
drinking water contaminants. States
must adopt their own regulations which
are at least as stringent aa the federal
regulations. This section of today's rule
describes the regulations and other
procedures and policies the States must
adopt to implement today's rule. EPA
previously promulgated program
implementation requirements in 40 CFR
part 142 on December 20.1969 (54 PR
52To implement today's rule. States will
be required to adopt the following
regulatory requirements when they are
promulgated: i 141.23. Inorganic
Chemical Sampling and Analytical
Requirements; S 141.24. Organic
Chemical Other Than Total
Trihalomethanes Sampling and
Analytical Requirements; i 141.32,
General Public Notice Requirement!
(i.e.. mandatory health effects language
to be included in public notification or
violations): i 141.40. Special Monitoring
for Inorganic and Organic Chemicals;
$ 141.81 (a) and (c). Maximum
Contaminant Levels for Inorganic and
Organic Chemicals; and \ 14i.Hl.
.Treatment Techniques for AcryUmide
and Epichlorohydrin.
In addition to adopting drinking water
regulations no less stringent than the
federal regulations listed above, EPA is
requiring that State* adopt certain
requirements related to this regulation in
order to have their program revision
application approved by EPA. In various
resptcts, the proposed NPDWRs provide
flexibility to tin State with regard to
implementation of the monitoring
reqairements under this rule. Because
State determinations regarding
vulnerability and monitoring frequency
will have a substantial impact with
implementation of this regulation, the
proposed rule requires States to submit
as part of their State program
submissions their policies and
procedures in these areas. This
requirement will serve to inform the
regulated community of State
requirements and also help EPA in its
oversight of State programs Thesr
requiremsnts are discussed below under
the section or special primacy
requirements. Today, EPA is also
promulgating changes to State
recordkeeping and reporting
requirements.
1. Special State Primacy Requirements
* To ensure that the State program
includes all the elements necessary for
an effective and enforceable program,
the State's request for approval must
contain the following: (1) If the State
issues waivers, the procedures and/or
policies the State will use to conduct
and/or evaluate vulnerability
assessments; (2) the procedures/policies
the State will use to allow a system to
decrease its monitoring frequency; and
(3) a plan that ensures that each system
monitors by the end of each compliance
period.
In general, commenters supported the
proposed primacy requirements.
However, one commenter characterized
the provisions as "resource
constraining," "confusing," "redundaat
"cumbersome," and "not necessary."
Several commenters were concerned
about the resource impact of
vulnerability assessments on State
programs. Several States desired
sufficient flexibility to tailor monitoring
requirements to site-specific conditions.
Anorner commenter urged the Agency to
allow "area wide" or geographic
vulnerability determinations.
EPA hu made several changes to
address tfaa commenlers' concerns. First'
as described elsewhere in today's rule.
EPA has adopted a standard monitoring
framework which synchronizes
monitoring schedules and standardizes
monitoring requirements. These changes
should reduce the confusion and
redundancy cited by one commenter.
One of die changes EPA is promulgating,
which is described in the section on
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Federal Register / Vol. 56, No. ,20 / Wednesday. January 30. 1991 / Rules and Regulations
monitoring, is shifting the responsibility
for conducting vulnerability
assessments from the State to the
system. The Scate retains, however, the
responsibility to approve the results of
vulnerability assessments and to issue
waivers. EPA believes that this change.
in part, addresses the resource
constraint issue cited by the
commenters States, by implementing
the standard monitoring framework and
by issuing waivers, will be able to tailor
monitoring requirements to site-specific
conditions in most cases. EPA will allow
States to issue "geographic" er "area
wide" waivers. This change is also
described in the section on monitoring.
The special primacy requirements
have been revised to establish criteria
for State descriptions of the waiver
programs the State will administer. EPA
will develop detailed guidance for use
by Regional Administrators in reviewing
primary applications, and in
administering this rule in non-primacy
States. As insurance against State
'abuse of discretion' in reducing
individual sampling frequency
requirements. EPA added § 142.16(0 to
establish aufhority for federal rescission
of State waivers that do not meet the
criteria established in 55 141.23.141.24,
and 141.40.
To encourage car°ful planning of the
framework's implementation. EPA has
added a special primacy pro-.ision in
today's rule-that requires the
development of State monitoring plans
that are enforceable under State law.
EPA is making this change to ensure
that all water systems complete
•monitoring (or conduct a vulnerability
assessment) by the end of each three-
year compliance period. In general,
State monitoring plans should require
approximately one-third of the systems
to monitor each year during each three-
year compliance period to provide for an
even flow of samples through State-
citified laboratories. States will be able
to establish their own criteria to
schedule the systems to monitor. If a
State does not have primacy for today'i
provision at the time th« initial
compliance period begins (i.e., January
1. 1993). then EPA will b« the primacy
agent. Because water systems may be
confused as to when each system must
monitor. EPA has established
procedi^-es (§5 141.23(k), 141.24{f)(23).
and 141.24(h](18)) that require systems
to monitor at the time designated by the
State. If EPA implements today's
provisions because a State has not yet
adopted the regulatory requirements in
toda>'s rule, EPi4 intends to we the
State's momionng schedule to schedule
systems during each compliance period.
EPA believes this approach will reduce
confusion over when each system
monitors once the State adopts today's
requirements.
2. State Recordkeeping Requirements
In §§ 141.16(d)(ll) through
112.16(d)(16). EPA proposed that States
v/ould maintain records of: (1) Each
vulnerability determination and its
basis; (2) each approval of reduced
monitoring and its basis; (3) each
determination that a system must
perform repeat monitoring for asbestos
and its basis; (4) each decision that a
system must monitor unregulated
conUminanUi; (5) each letter from a
system serving fewer than 150 service
connections that it is available for
monitoring of unregulated contaminants;
and (6) annual certifications that
acrylamide and epichlorohydrin are
used within Federal limits for the
combination of dose and monomer
levels. EPA also requested comment on
whether the existing record retention
requirement of 40 years is reasonable, or
should be modified.
In general, commenters (mostly
States) characterized the proposed
recordkeeping requirements as
"absurd," "terrible." "excessively
burdensome," and "unwarranted." The
most substantive comments are listed
below. EPA has revised this part to
conform to the standard monitoring
framework, and to provide auditable
records during Federal oversight
reviews.
One commenter said that the unduly
diverse and complex sampling periods
will exacerbate the complexity of the
record/file systems. In response, the
Agency notes that the sampling periods
have been consolidated into the
Standard Monitoring Framework, in
order to simplify the program
requirements for local. State, and
federal personnel. This framework
consists of repeating three-year
compliance periods within repeating
nine-year compliance cycles.
Another commenter stated that
maintaining documentation of
assessments resulting in non-vulnerable
status or reduced sampling frequencies
is less important than addressing CWSs
with real problems. System by system
documentation of vulnerability
assessments is unnecessary; State
summaries of each assessment should
suffice. Many States either have
inadequate resources to manage
complex record systems, or will have to
divert resources from more important
activities, such as technical assistance
for small communities.
In response, EPA does not disagree
with the commenter's priprities, but the
Agency also believes that a precise
record of each decision affecting publ;
health is necessary. The commenter
should note that States a-re not require
to conduct vulnerability assessments.
and States may reduce the resource
impact of these regulations by app'yir.
uniform monitoring requirements to all
CWSs. However, if vulnerability
assessments are used as the basis for
granting waivers from the uniform
monitoring requirements, there must b«
complete documentation of those
'assessments and the basis for each
decision. In the final rule. EPA has
clarified that records of.only the most
recent assessment and monitoring
frequency determination need be
maintained.
One commenter stated that since
authority to enter and inspect is a
primacy requirement under
1142.10(b)(6)(iii). the requirement for
records of sampling availability letters
and the letters themselves, is
superfluous. In response, EPA agrees
with this comment, and has deleted tlu
State recordkeeping requirement of
systems which serve less than 150
service connections which send letters
of availability.
Another comment asserted that
annual certifications of proper
acrylamide and epichlorohydrin
applications are unnecessary; the
application requirements should be
sufficient.
In response, EPA believes the
requirement is a reasonable means of
attempting to confirm proper applies tic
of these chemicals, considering that the
minimum frequency for sanitary survey
is five years.
Another ccmmenter pointed out that
the 40-year record retention requiremer
is an unreasonable burden on State ,•
resources.
.In response, EPA has reduced the
standard monitoring records retention
requirement to 12 years. This covers a
nine-year monitoring cycle plus a three
year monitoring period, to allow time fi
more current records to replace older
records.
3. Stite Reporting Requirements
In 5 5 142.15(a)(12) through
142.15(a)(17), EPA proposed that States
would report lists of: (1) Systems for
which vulnerability assessments have
been conducted, the assessment result;
and their bases; (2) systems that have
been permitted to reduce their
monitoring frequencies, the bases for th
reduction, and the new frequencies; (3)
systems that must conduct repeat
monitoring for asbestos; (4) systems
.serving fewer than 150 service
-------
3578 Fedatal Rayatar / VoL 56. No. 20 / Wednesday, January 30. 1381 I Rules and Regulations
'onnections that have notified die State-
jf their availability foi tempting, of
jnregulated contaminant** and (5$
jystems that have certified complianc*
with treatment requirements for
icrylamide and epkhlorohydrin. EPA
ilso proposed that States, report the-
•esults of monitoring for unregulated
:ontanvnanta.
Generally, commsnrers chaiacteriztd
:he proposed rule a*-"redundant"
'useless," "onerous." "exce*»ive,"
burdensome." "unnecessary." and
'inconsistent with other reporting
requirements."
In addition, many comments cai§«d
the following pointa:
• ."he appropriate vehicle* for EPA
oversight are review of primacy
applications and annual nn-«ite program
management audit*.
• The proposed reporting
requirements are redundant to thos«
activities and therefore inappropriate.
« EPA's need for, or prospective use
of. the data to ba reported is unclear.
• Reporting should be standardized
with other rules, and conducted through
a computerized date bare.
In response; EPA agrees with these
points after reviewing the Agency's
information needs. EPA has determined
that the core reporting requirements of
the Primacy Rule, December 20,1986,
ere sufficient for purposes of routine
program oversight. Therefore, the
Agency has deleted the proposed
reporting requirements, except for the
requirement to report result* of
monitoring for unregulated
contaminants in 1142.15(a)(15}. These
results are needed for development of
future MCL*.
V. Economic Analyst*
Executive Order 12291 requires EPA
»nd other regulatory agencies to perform
i Regulatory Impact Analysis (RIA) for
ill "major" regulations, which are
iefiend as those regulations which
.Tipose an annual co*t to the economy
,f 5100 million or more, or meet other
criteria. The Agency has determined
•_s.at this action constitutes a "mafor"
regulatory action for the purposes of the-
Exscuuve Order. Therefore, in.
accordance with the Executive Order.
the Agency has conducted an
assessment of the benefit* and coat* of
t-ath the proposed and final rule*.
The R1A* supporting the proposed
-,',e (see "Regulatory Impact Analysis of
Proposed Inorganic Chemical
*''Filiations " March 31.1968. and
Regulatory Impact Analysis, of
Prcpo»ed Synthetic Organic Chemical
"egulaaons." Apnl 1989) estimated an
incremental annualized cost to the
nation of $42 million for treatment and
waste disposal. Monitoring co»t* for the
proposed rule were estimated to be-
about $29 million/year incrementally.
Thus, the total incremental annualized
cost to the nation of the proposed
requirements was about $71 million/
year. In addition, unregulated
contaminants were estimated to result
in a one-time cost of $42.millian.
In response to public comments and
receipt of new data or information. EPA
made several change*.to the proposed
rule which resulted in an overall
increase in the projected compliance
costs for the final rule. In addition.
revised unit coat and occurrence data
were incorporated into the final RIA*.
These changes, and their corresponding,
effects on.ths originxl cxmr estimate* arc
described below. The cost of compliance
for aldicarb, aldiearb sulfoxide. aldicarb
suifone, barium and pwntachloiophenol
continue to be included in the RIA
supporting today's rule.
A. Cost of Final Rula
Table 28 show* the results of the
Regulatory Impact Analyse* which
support today's final rule. MCLs
promulgated in today's rule for barium.
chromium, and selenium are all lea*
stringent than existing National Interim-
Primary Drinking. Water Regulations
(NTPDWR). A* a- re*ult the incremental
annualized treatment and waste
disposal cost of S64 million/year are
associated with the more stringent
MCLs for cadmium and the SOC* which
are promulgated in today'* final rule.
Incremental monitoring cost* are
estimated to be about $24 million/year.
Thus, the- incremental annualized
compliance cost to the nation of about
$88 million/year is some what higher
than the $71 million/year estimated for
the proposed rule. In addition,
unregulated contaminants are expected
to result in a one-time cost of $39
million, which is lower than the $42.
million o«timatpf^ tnr thp proposal
Approximately 1242 community and
non-transient non-community water
system* are not currently in compliance
with existing NIPDWR* and would not
be in compliance- wtth thia rule either.
As a result these systems will incur
compliance costs associated with
enforcement of today'*rule. The coat of
thes* 3,242 sys*em»to come into
compliance would be SS6Q million p«r
year for treatment and waste disposal
and $1.5 million per year for monitoring.
TABLE 28.—SUMMARY ESTIMATES FOR
FINAL IOC AND SOC REGULATIONS
Systww « Violation....
Complianc* Co*t*.._
— Monitoring
— Tfaaawa* and
Qtapnaaf Cocin
d3% __.....
Unragutatatf
CMttMMT
Stata
Coats MSaf (SM) ..
rtiitiraar M&W«%
Populate* W*h
Raduead
Expoour*
(nStowt «.«
Oapoav Caaaa»«.
see
'3.110
$78
21
•57
2.7
72
IOC
165
&10
2.5
7.0
.„.„_
0.2
Total
3.265
$88
. 24
64
3B
21
17
2.9
72
' IneJybia- an M&iialod 825 fyvtwna «ftefc <**
viotaM m« propoa«d MCL tar p«ntacNorapr*no<.
«lndud»§ *1* m*«e« » »•« tar p»itacNor»
ph«nol, wt*^ ia bamg ian'opoaad itaawtiafa Kxiay
In tn» Faclaral ftagtatar.
Table 28 also shows the benefits of
today'., final rule. Compliance with the
IOC* MCLs is expected to provide
reduced exposure to almost 200.000
people resulting from lowering the MCL
for cadmium. The type* of health effects.
expected to be avoided include chronic
toxic effects such a* kidney- toxicity.
Compliance with tha SOCa MCL* i*
expected to provide reduced exposure to
almost three million people and prevent
about 72 case* of cancer per year.
B. Comparison to Proposed Rule '
Table 29 compare* the- co*t» and
benefit* of today'ft final rule to those
estimated for the proposal The
differences in the cost estimate* are
attributable to a variety of changes in
the rule and in the available input data
used in the analyse*. Among the more
influential changes are tha following:
1. Monitoring Requirement*
As described in section H1(D] of
today's preamble, the monitoring
requirement* in today's rule are
somewhat different from those included
in the proposed rule. A direct
comparison between the monitoring
costs estimated in the propose! and
those estimated for the final rule i* not
entirely appropriate because the coats
estimated for the proposal were
aggregated over nine years, whereas the
costs for the final rule are aggregated
over 18 years.
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Federal Register / Vol. 56, No. 20 / Wednesday. January 30. 1991 / Rules and Regulations 3577
TABLE 29.—COMPARISON OF COSTS FOR
PROPOSED AND FINAL RULES
Proposed-
Final
f Systems ............ 2.475 3.275
Cwxtal Costs iJM) .......... $361 i $554
*nnua;,Z8d Cw'.al Ccs'S 'SM/
YR) . • 24 37
Donation & Maintenance Costs '
iSM.'VR) ............... 18, . 27
Monitoring Costs iSM. rP) ......... ".' 29J 24
'otal Annua'rzed Costs ($M/YR) , 71 1 88
•Jnregulated Contamirtsnt Mora- ' |
uxing ($M) ...: ............................ ; *2j 39
Slt!» lmp,enrvnttnof> Costs: , ,
1,'iMliSM) .................................... i .. 2*1 21
• Out-year HM/YR)..: ................. ...... . 1*1 17
p»ntacntofopn«nol. wtuch « ropro-
Table 29 shows that the monitoring
costs for the final rule are somewhat
iess than the monitoring costs estimated
for the proposal. This decrease is
primarily due to a reduced number of
systems which are expected to be
vulnerable to SOC contamination.
Current VOC monitoring cost estimates
are expected to be higher than those
estimated for the proposal for the
following reasons:
• Svstems are phased in more quickly
in the final rule. Thus, systems
previously expected to monitor only
once every nine years are now expected
to monitor for VOCs three times during
an 18 year cycle; and
• The final rule requires all
vulnerable systems to incur VOC
monitoring costs once/year, whereas the
proposal requires systems serving fewer
lhan 3.300 people to Incur monitoring
costs only once during the nine year
cycle and larger system* only incur
monitoring costs twice during the nine
year cycle.
2. Changes in MCLa
Although several MCL» in the final
rule have changed from those that were
proposed (e.g., toluene, toxaphene), only
the proposed MCL for
pentachlorophenol it more stringent as-
to resull in additional impacts. The
reproposed MCL for pentachlorophenol
is 0.001 mg/1, compared to the proponed
standard of 0.2 mg/1.
3. Changes in Occurrence Data
Occvurence data used in the final
Phase II RIAs have been changed to
include the following:
• Revisions to the NIRS groundwater
occurrence estimates for barium,
cadmium, chromium, mercury and
selenium; and
• Additional occurrence data on
pentacnlorophenol provided by AWWA
,-es jjled in estimating 825 systems
would exceed the proposed MCL of
0.001 mg/l.
4. Changes in Unit Treatment Cost
Estimates
Changes in system design flow
assumptions resulted in revised
treatment and waste disposal unit cost
estimates for both lOCs and SOCs.
The combined effects of these changes
are lower national treatment and waste
disposal costs for lOCs, but higher
national treatment and waste disposal
costs for SOCs. The revised design flow
assumptions directly resulted in higher
household annual costs for both lOCs
and SOCs.
C. Cost to Systems
Table 30 suggests that the cost
impacts on water systems and
consumers affected by most of the
synthetic organic and inorganic
contaminants are small and vary
depending upon the specific chemical
contaminant and the size of the public
water system. Households served by
serving more than 3,300 people could be
subject to water bill increases of
between $5 and $205 per year, if their
systems have SOC or IOC
contamination greater than the MCLs.
EPA believes that these costs are
affordable.
TABLE 30.—UPPER BOUND HOUSEHOLD
COSTS (S/HH/YEAR)
System size (population served)
25-100
101-5OO , ,
3300-10000
25 000-50 OOO
SOC*1
$596
233
64
42
31
IOC««
$896
442
122
167
205
1 Granular Activated Carbon or Packed Tower Aer-
ation.
• Wngrtted average ba*ed on probaMitwe aseoci-
ated v«m alternative treatments (i.e., convendonel.
feme softening, on exchange, reverie oamosx, actt-
vated alumna, activated carbon and otnen).
Small systems, those serving fewer
than 500 people, incur higher per
household costs because they do not
benefit from engineering economies of
scale. Households served by these small
systems would have to pay significantly
more, should their system have SOC or
IOC contamination greater than the
proposed MCL. In the case of SOCs,
typical annual water bills could increase
by as much as $598. which EPA believes
may not be affordable. In the case of
IOC's, water bills in small supplies could
climb an additional $898 per year in
contaminated systems.
D. Cost to State Programs
In 1988 EPA and the Association of
State Drinking Water Administrator*
(ASDWA) conducted a survey of State
primacy program resource needs for
implementing the 1386 SDWA
amendments. The State implementation
costs for the proposal were estimated to
be about $14 million per year, after an
initial cost of $24 million. The survey
results have since been updated to
include additional respondents. Thus.
the revised State implementation costs
for today's final rule is estimated to be
about $21 million initially and S17
million/year in the out-years.
Over half of the initial and out-yearv
costs are expected to be associated wit!:
expanding laboratory capabilities for
anal'-'ing samples. After laboratory
expar- '.on, development of vulnerability
criteria, revising State primacy
agreements, training staff on the rules.
modifying the data management system.
educating the public on the rules, and
formal enforcement of the rules are each
expected to require about one rr.illion
dollars initially to be implemented. VV::h
respect to out-year costs, formal
enforcement and public education are
expected to require the most resources
after laboratory expansion costs.
The State survey results for the Phase
II requirements are based on the
proposal: however, the survey
questionnaire was carefully reviewed to
determine if the estimated costs should
be revised. This review indicated that
the estimated State implementation
costs lor the proposal should not be
significantly different from those
expected for the final rule.
V. Other Requirement*
A. Regulatory Flexibility Analysis
The Regulatory Flexibility Act (RFA)
requires EPA to consider the effect of
regulations on small entities [5 U.S.C.
602 et seq.]. If there is a significant effect
on a substantial number of small
systems, the Agency must prepare a
RFA describing significant alternatives
that would minimize the impact on smaL
entities. The Agency had determined
that the proposed rule, if promulgated,
would not have a significant effect on a
substantial number of small entities.
The RFA for the final rule indicates
that of 199.390 commuiury and non-
community water supplies serving fewer
- than 50.000 people, about 6,473 (3.2%)
are estimated to exceed the final MCLs
promulgated in today's rule. Compliance
costs estir-ated for the 6,473 systsrns
required to install treatment are about
$313 mi.llion per year. Because of the
nitrates monitorii^ requirements, all
199.390 systems are estimated to comply
with the monitoring requirements. The
monitoring cost* for these small .systems
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3S78
Federal Register / Vol. 56. No. 20 / Wednesday. January 30. 1091 / Rules and Regulations
ere estimated to be about $4-million/
year for lOCs and about $20 million/
year for SOCs. Based on the RFA
rcaulti. EPA has determined that the
6.473 systems required to install
treatment w.U be significantly affected
by this rule.
While a "substantial" number of the
small water supplies serving fewer than
50.000 persons will be affected by the
monitoring requirements, their
/ production costs will not increase by
five percent. Therefore, the impact on
this substantial number of systems is
not considered "significant" according
to RFA guidelines. There are 6X73 small
systems estimated to require treatment
and thus, incur -significant" increases in
coats. However, 6.473 systems is only
3.2S of 199.390 systems and. according
to EPA guidelines for conducting RFAs,
less than 20% of a regulated population
is rot considered a substantial number.
Despite the results, of this RFA, the
Agency considers several thousand
systems to be substantial and has
attempted to provide greater flexibility
to small systems while still providing
adequate protection of the public health.
The most significant change to the
proposed rule which reduce* the burden
on small systems involve* standardized
monitoring requirements and the
opportunity for waivers. In addition.
EPA has re-duced some monitoring
requirements for systems serving <3.300
people.
As well as these changes in the role,
the 1988 Amendments to the SDWA
provide small systems with exemptions.
Thus, the Agency has tried to relieve
small systems as much as possible from
the cost* of compliance with the
regulatory" requirements while still
providing adequate protection to the
health of their c jnsumers.
B. Paperwork Reduction Act
The information collection
requirements in this rule have been
submitted for approval to die Office of
Management and Budget (OMB) under .
the Paperwork Reduction Act l«-U.S.C.
3501 et seq.\. An Information Collection
Request (ICR) document has been
prepared by EPA and a copy may. be
obtained from: Sandy Fanner,
Information Policy Branch. EPA. 401 M
Street. SW. (PM-ZZ3). Washington, DC
c: by calling 202-3*2-2740.
t^ub'.ic reporting burden for. today's
final r.Je is estimated to average Q.r
hours per response The entire re&Jated
population of 200.183 systems will incur
some morntoTir.g corts for nitrates. Of
thf KM'. population. 75.703 systems are
expected to incur-monitoring costs for
"T!'snrInarrtT other than .nitrates. The
,'•"!•., eslksste u about 1.2
million hours per year. In addition.
systems monitoring for unregulated
contaminants are expected to incur a
one-time reporting burden of 0.5 hours/
response resulting in a total of 31.481
hours. The monitoring cos's asaociated
with these information col'pction
requirements are somewhat lower than
those estimated for the proposed rule.
"Specifically. IOC monitoring co*t» have
' increased from $4 million/year to $4.5
million/year. SOC monitoring costa
have decreased from $27 million/year to
$21 million/year, and the one-time
monitoring costa for unregulated
contaminant* have decreased from $42
million to $39 million. The change in co»t
is due to the numerous change* made to
the monitoring, recordkeeping, and
reporting requirements that had been
proposed. The information collection
requirement* are not effective until
OMB approve* them and a technical
amendment to that effect is published in
the Federal Regular.
VI. Public Docket and References
All supporting material* pertinent to
the promulgation of thi* rule are
included in the Public Docket located at
EPA headquarter*. Washington. DC. The
Public Docket is available for viewing
by appointment by calling the telephone
number at the beginning of this notice.
All public comments received on the
1986 proposal are included in the
Docket.
All referencss cited in thi»-notice are
included in the Public Docket together
with other correspondence and
information.
list of Subject* in 40 CFR Parts 141.142
and 143
Administrative practice and
procedure. Chemicals, Reporting and
Recnrdkeeping requirement*. Water
supply,
Octed: December 31.1990.
F. HMTT tfabfcfct
Acting Administrator.
For the reason* set forth in the
preamble, chapter I of Title 40 of tl.a
Coda of Federal Regulation* i* propoaed
to be amended a* follow*:
PART t*1—KATJOHAL PRIMARY
DRINKIMQ WATER REGULATIONS
1. Tha authority citation for part 141
continue* to read as follows:
Authority. 42 U.&C. 300f. 300»-1. 3OOf-2.
300fr-3. 3009-4. 30Bfr-S. 300g-«. 300f-t- "*
300J-8.
2. Section 141.2 U amended by adding.
in alphabetical order, definition* for
"Compliance cycle," "Compliance ^
period," "Initial compliance period." and
"repeat compliance period" to read as
follows:
§ Wrt.2
Compliance cycle means the nine-
year calendar year cycle during which
public water systems must monitor.
Each compliance cycle consist* of three
three-year compliance periods. The first
calendar year cycle begin* January 1.
1993 and ends December 31. 2001: the
second begins January 1. 2002 and ends
December 31. 2010; the third begin*
January 1, 2011 and end* December 31.
2019.
Compliance period mean* a three-
year calendar year period within a
compliance cycla. Each compliance
cycle has three three-year compliance
periods. Within the first compliance
cycle, the first compliance period runs
from January 1. 1993 to December 31,
1995; the second from January 1. 1996 to
December 31, 1998; the third from
January 1. 1999 to December 31. 2001.
• * • • «
Initial compliance period means the
first full three-year compliance period.
which begins at least 18 months after
promulgation.
• • • « *
Repeat compliance period means any
subsequent compliance period after the
initial compliance- period.
3. In 5 141.11, paragraph (b) is
amended by removing the entry for
"silver" from the table, and by revising
the introductory text of paragraph (b) to
read as follows; .
f141.Tt Itextmom contaminant tev««* for
Irxxgartc ctwnteoi*.
«••••-
(b) The following maxi. .. n
contaminant levels for cadmium,
chromium, mercury, nitrate, and
selenium shall remain effective until July
30,1992.
. . • • •
3. Section 141.12 i* revised to read a»
follows:
f141.1t Minimum cmitswlnarrt t«y«t» for
otrgsnfc ohwnteals.
The following are the maximum
contaminant levels for organic
chemicals. The m«*<""™ contaminant
levels for organic chemicals in
paragraph (a) of this section apply to all
community water systems. Compliance
with the maximum contaminant level in
paragraph (a) of this section is
calculated pursuant to S 141.24. The
maximum contaminant level for total
trihalomeihanes. in paragraph (c) of this
section appae* only to. community water
systems which serve a population of
-------
Federal Register / Vol. 58, No. 20 / Wednesday, January 30. 1991 / Rules ..rd Regulations 3579
10.000 or more individuals and which
add a disinfectant (oxidant) to the water
in any part of the drinking water
treatment process. Compliance with the
maximum contaminant level for total
tnhalomethanes is calculated pursuant
to § 141.30.
' Level.
-- milligrams
p«r War
(i) Chlorinated hydrocarbons: Endrm
(1.2.3.4.10.lO-he*«chloro-8.7-
•ooxy-1.4. 44.5.6.7.8.81 -octanydrc-
1,4-endo. •TMjo-5.S-dinwtna.no
napnmalone)
romocr*yometf*«ne.
tnbromometnane (bromoform) and
tncritoromatnane (chloroform))
0.0002
0.1
4. Section 141.23 is revised to read as
follows:
§141.23 Inoryanlc ch«mlc«) Mmpting and
anatyttca) requirement*.
Community water systems shall
conduct monitoring to determine
compliance with the maximum
contaminant levels specified in § 141.62
in accordance with this section. Non-
transient, non-community watersystems
shall conduct monitoring to determine
compliance with the maximum
contaminant levels specified in § 141.62
in accordance with this section.
Transient, non-community water
systems shall conduct monitoring to
determine compliance with the nitrate
and nitrite maximum contaminant levels
in 5 141.11 and 5 141.62 (as appropriate)
in accordance with this section.
(a) Monitoring shall be conducted as
follows:
(1) Croundwater systems shall take a
minimum of one sample at every entry
point to the distribution system which is
representative of each well after
treatment (hereafter called a sampling
point) beginning in the compliance
period starting January 1.1993. The
system shall take each sample at the
same sampling point unless conditions
make another sampling point more
representative of each source or
treatment plant.
(2) Surface water systems shall take a
minimum of one sample at every entry
point to the distribution system after
any application of treatment or in the
distribution system at a point which is
representative of each source after
treatment (hereafter called a sampling
point) beginning in the compliance
period beginning January 1,1993. The
system shall take each sample at the
same sampling point unless conditions
make another sampling point more
representative of each source or
treatment plant.
Note: For purposes of thin paragraph. " •
surface water systems include systems w.'.h a
combination of surface and ground sources.
(3) If a system draws water from more
than one source and the sources are
combined before distribution, the
system must sample at an entry point to
the distribution system during periods of
normal operating conditions (i.e.. when
water is representative of all sources
being used).
(4) The State may reduce the total
number of samples which must b°
analyzed by allowing the use of
compositing. Composite samples from a
maximum of five sampling points are
allowed. Compositing of samples must
be done in the laboratory.
(i) If the concentration in the
composite sample is greater than or
equal to the detection limit of any
inorganic chemical, then a follow-up
sample must be taken within 14 days at
each sampling point included in the
composite. These samples must be
analyzed for the contaminants which
were detected in the composite sample.
Detection limits for each analytical
method are the following:
DETECTION LIMITS FOR INORGANIC CONTAMINANTS
Cor.lammant
A'sbesto*
B»num .. .. ,
C^rorrium . . „ ,,
' MCMmg/l)
<
7 MLF «
..„,.._ 2
i
: i ooos
1 '
.0.1
0002
I 10 (as N)
t
i
i
1 (ts N)
!
1 005
i
Trartsmtsswn Electron Microscopy '••'
Atomc Absorption; direct aspiration
Atomic Absorption; furnace technique - • -
inductivefy Coup"** Plasma - -.•-.
Atorao Absorption: furnace technique •
Inductively Coupled Plasma ,- - :
Manual Cold Vapor Technique f. >
Autonited CoW Vapor Technique •
MaruaJ Cadmium Reduction :
Automated Hydraane Reduction • ;
Spectrophutmiietiic
Automated Cadrmjm Reduction •. •
Alomc Absorption: furnace
Atomic Absorption; gaseous hydride
Detection limit
(mg/l)
0.01 MFL
0.002
0.1
0.002(0001) '
00001
0.001 ' :
0.001
0.007 (0.001) >
0,0002
OOOC2
0.01
0.01
0.05
1
0.01.
001
0.05
0.01
0.004
0.002
0.002
1 Using ccocentridon technique in Appendix A to EPA Method 200.7.
' MFL - mdlon fiben per liter > 10 .m.
(ii) If the population served by the
8>stem is >3,300 persons, then
compositing may only be permitted by
the State at sampling points wVJiin a
single system. In systems serving <3,300
persons, the State may permit
,-.r.-.; os:'Jrt£ among different systems
provided the 5-sample limit is
maintained.-
(5) The frequency of monitoring for
asbestos shall be in accordance with-
paragraph (b) of this section; the
frequency of monitoring for barium.
cadmium, chromium, fluoride, mercury,
and selenium nhail be in accordance .
with paragraph (c) of this section: the
frequency of monitoring for nitrate shal
be in accordance with paragraph (d) of
this section; and the frequency of
monitoring for nitrite shall be in
accordance with paragraph (e) of this
section.
-------
358Q
Federal RegJater / Vol. 56. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations
(b) The frequency of monitoring
conducted to determine compliance with
the maximum contaminant level for
asbestos specified in § 141.62(b) «hall be
conducted as follow*:
(1) Each community and non-
transient, non-community water system
is required to monitor fcr asbestos
during the first three-year compliance
period of each nine-year compliance
cycle beginning in the compliance period
starting January 1.1993.
(2) If the system believes it is not
vulnerable to either asbestos
contamination in it* source water or due
to corrosion of asbestos-cement pipe, or
both, it may apply to the State for a
waiver of the monitoring requirement in
paragraph (b)(l) of this section. If the
State grants the waiver, the system is
not required to monitor.
(3) The State may grant a waiver
based on a consideration of the
following factors:
(i) Potential asbestos contamination of
the water source, and
(ii) The use of asbestos-cement pipe
for finished water distribution and the
corrosive nature of the water.
(4) A waiver remain! in effect until
the completion of the three-year
compliance period. System* not
receiving a waiver must monitor in
accordance with the provisions of
paragraph (b)(l) of this section.
(5) A system vulnerable to asbestos
contamination due solely to corrosion of
asbestos-cement pipe shall take one
sample at a tap served by asbestos-
cement pipe and under conditions where
asbestos contamination is most likely to
occur.
(6) A system vulnerable to asbestos
contamination due solely to source
water shall monitor in accordance with
the provision of paragraph (a) of mis
section.
(7) A system vulnerable to asbestos
contamination due both to its source
water supply and corrosion of asbestos-
cement pipe shall take one sample at a
tap served by asbestos-cement pipe and
under conditions where asb«*tos
contamination is most likely to occur.
(8) A system which exceedz the
maximum contaminant levels as
determined in 1141.23(i) of this section
shall monitorquaileily beginning in the
next quarter after the violation occurred.
(9) The State may decrease the
quarterly monitoring requirement to the
frequency specified in paragraph (b)(l)
of this section provided me Stata hat
determined that the system LI reliably
and consistently below the mmdmnm
contaminant level In no case can a
State make this determination unless a
grouridwater system takes a minimum of
rwe quarterly samples and a surface (or
combined surface/ground) water system
takes a minimum of four quarterly
samples.
(10) If monitoring data collected after
January 1.1990 are generally consistent
with the requirements of 5 lll.23(b).
then the State may allow systems to use
that data to satisfy the monitoring
requirement for the initial compliance
pei iod beginning January 1.1993.
(c) The frequency of monitoring
conducted to determine compliance with
the maximum contaminant levels in
§ 141.02 for barium, cadmium.
chromium, fluoride, mercury, and
selenium shall be at follows:
(1) Groundwater systems shall take
one sample at each sampling point
during each compliance period
beginning in the compliance period
starting January 1.1993. Surface water
systems (or combined surface/ground)
shall take one sample annually at each
sampling point beginning January 1.
1993."
(2) The system may apply to the Stale
for a waiver from the monitoring
frequencies specified in paragraph (c](l)
of this section.
(3) A condition of tire waiver shall
require that a system shall take a
minimum of one sample while the
waiver is effective. The term during
which the waiver is effective shall not
exceed one compliance cycle (i.e., nine
years).
(4) The State may grant a waive*
provided surface water systems have
monitored annually for at least three
years and groundwater systems have
conducted a minimum of three round* of
monitoring. (At least one sample shall
have been taken since January 1.1990).
Both surface and groundwater systems
shall demonstrate that all previous
analytical results were less than the
maximum contaminart level. Systems
that use • new water source are not
eligible for a waiver until three rounds
of monitoring from, the new source have
bean completed.
(5> In determining the appropriate
reduced monitoring frequency, the State
shall consider.
(i) Reported concentrations from all
previous monitoring;
(ii) The degree of variation in reported
concentrations; and
(iii) Other factors which may affect
contaminant concentrations such as
changes in groundwater pumping, rates.
changes in the system's configuration.
changes in the system's operating
procedure*, or changes in stream flows
or characteristics.
(8) A decision by the State to grant •
waiver shall be made in writing and
shall set forth the basis for the
determination. The determination may
be initiated by the State or upon an
application by the public water system.
The public water system shall specify
the basis for its request. The State shall
review and. where appropriate, revise
its. determination of the appropriate
monitoring frequency when the system
submits new monitoring data or wher
other data relevant to the system's
appropriate monitoring frequency •
become available.
(7) Systems which exceed the
maximum contaminant levels as
calculated in i 141J3(i) of this section
shall monitor quarterly beginning in the
next quarter after the violation occurred.
(8) The State may decrease me
quarterly monitoring requirement to th •
frequencies specified in paragraphs
(c)(l) snd (c)(2) of this section provided
it has dsterrtiined that the system is
reliably and consistently below the
maximum contaminant level. In no case
can a State make this determination
unless a groundwater system takes a
minimum of two quarterly samples and
a surface water system takes a minimum
of four quarterly samples.
(d) All public water systems
(community; non-transient, non-
community; and transient, non-
community systems) shall monitor to
determine compliance with the
maximum contaminant level for nitrate
in i 141.62.
(1) Community and non-transient.
non-community'water systems served
by groundwater systems shall monitor
annually ^"^""'"8 January 1.1993;
systems served by surface water shall
monitor quarterly beginning January 1,
1993. '
(2) For community and non-transient.
non-commurrity water systems, the
repeat monitoring frequency for
groundwater systems shall be quarterly
for at least one year following any one
sample in which the concentration is.
>50 percent of the MCL. The State may
allow a groundwater system to reduce
the sampling frequency to annually after
four consecutive quarterly samples are
reliably and consistently less than the
MCL.
(3) For community and non-transient
non-community water systems, the State
may allow a surface water system to
reduce the sampling frequency to
annually if all analytical results from
four consecutive quarters are < 50
percent of tha MCL. A surface water
system shall return to quarterly
monitoring if any one sample is >50
percent of tho MCL.
(4) Each transient non-commumrj
water syntem shall monitor annua rjr
beginning January 1.1993.
-------
Federal Register / Vol. 56. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations 358".
(5) After the initial round of quarterly
sampling is completed, each community
and non-transient non-community
system which is monitoring annually
shall take subsequent samples during
the quarter(s) which previously resulted
in the highest analytical result.
(e) All public water systems
(community; non-transient, non-
community; and transient, non-
community systems) shall monitor to
determine compliance with the
maximum contaminant level for nitrite
in 5 141.62(b).
(1) Ail public water systems shall take
one sample at each sampling point in the
compliance period beginning January 1.
1993 and ending December 31.1995.
(2) After the initial sample, systems
where an analytical result for nitrite is
<50 percent of the MCL shall monitor at
the frequency specified by the State.
(3) For community, non-transient, non-
community, and transient non-
community water systems, the repeat
monitoring frequency for any water
system shall be quarterly for at least one
year following any one sample in which
the concentration is >50 percent of the
MCL. The State may allow a system to
reduce the sampling frequency to
annually after determining the system is
reliably and consistently less than the
MCL
(4) Systems which are monitoring
annually shall take each subsequent
sample during the quart«r{:) which
previously resulted in the highest
analytical result.
(f) Confirmation samples:
[1] Where the results of sampling for
asbestos, barium, cadmium, chromiiut.
fluoride, mercury, or selenium indicate
an.exceedance of the maximum
contaminant level, the State may require
that one additional sample be collected
as soon as possible after the initial
sample waa taken (but not to exceed
two weeks) at the same sampling point.
(2) Where nitrate or nitnte sampling
results indicate an exceedance of the
maximum contaminant level, the system
shall take a confirmation sample within
24 hours of the system's receipt of
notification of the analytical results of
the first sample ^-''ems unable to
comply with the 24-bour sampling
requirement must immediately notify the
consumers served by the area served by
the public water system in accordance
with § 141J2...Sy8tems exercising this
option must lake and analyze a
confirmation sample within two weeks
of notification of the analytical results of
the first sample.
(3) If a State-required confirmation
sample is taken for any contaminant.
then the results of the initial and
confirmation sample shall ba averaged.
The resulting average shall be used to
determine the system's compliance in
accordance with paragraph (i) of this
section. States have the discretion to
delete results of obvious sampling
errors.
(g) The State may require more
frequent monitoring than specified in
paragraphs (b), (c), (dj and (e) of this
section or may require confirmation
samples for positive and negative results
at its discretion.
(h) Systems may apply to the State to
conduct more frequent monitoring than
the minimum monitoring frequencies
specified in this section.
(i) Compliance with J} 141.11 or
141.82(b) (as appropriate) shall b«
determined based on the analytical
result(s) obtained at each sampling
point.
(1) For systems which are conducting
monitoring at & frequency greater than
annual, compliance with the maximum
contaminant levels for asbestos, barium,
cadmium, chromium, fluorida. mercory,
and selenium is determined by a running
annual average at each sampling point
If the average at any sampling point is
greater than the MCL. then the system n
out of compliance. If any one sample
would cause the annual average to be
exceeded, then the syntem is out of
compliance immediately. Any sample
below the detection limit shall be
calculated at zero for the n-n-ose of
determining the annual average.
(2} For systems which are monitoring
annually, or less frequently, the system
is out of compliance with the maximum
contaminant levels for asbestos, bariun
cadmium, chromium, fluoride, mercury
and selenium if th* level of a
contaminant at any sampling point ii
greater than the MCL. If a confirmation
sample is required by the State, the
determination of compliance will be
baaed on the average of the two
samples.
(3) Compliance with the maximum
contaminant levels for nitrate and
nitrate is determined based on one
sample if the levels of these
contaminants are below the MCLs. If th
levels of nitrate and/or nitrite exceed
the MCLs in the initial sample, a
confirmation sample is required in
accordance with paragraph (f)(2) of this
section, and compliance shall be
determined based on the average of the
initial and confirmation samples.
(4) If a public water system has a
distribution system separable from othc
parts of the distribution system with no
interconnectiona, the State, may allow
tha eysiaaa to give pablic notice to only
the area served by that portion of the
system which is out of compliance.
(ft Eada public waler systam shall
raoaitor et tfcs tissa designated by the
State during each compliance period.
(k) Inorganic analysis:
(1) Analysis for asbestos, barium.
cadmium, chromium, mercury, nitrate.
nitrite, end ssle5uum iihaH b« conductec
using the following methods:
INORGAWC COWTAMIWANTS ANALYTICAL METHODS
Reference (nwff»d No.
Contaminant
'
Cad
lt"**u"
^
'
i Methodology li
i
, EPA '
EPA • •
: 2062
! 208 1
....'. 2O0.7 '•«
, 213.2
....] aeo.7A •
218.2
200.7 '••
»$2
-. 3633
' 353,1
3S3 2
, 30ttO
i 354.1
ASTM«
D3223-«5
OSSS7-S5E
^ D38S7-85A
1
SM»
304
303C
•304.
304'
3Q3JC
41SC
416F
OttMT
w«wwGys»*o '
B-1091 '«
-------
3582 Federal Register / Vol. 58. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations
• INORGANIC CONTAMINANTS ANALYTICAL METHODS—Continued
Reference (method No,
Conu/nnint
_
Metnoooiogy >•
EPA '
353.2
3S3.3
300.0
270.3
270.2
ASTM «
D3867-85A
D3867-OSB
D3859-84A
03659-048
SM>
418F
<118C
303E
304«
Other
B-1011 10
1-3667-85 '
»"Method* of Chemical Analysis of Water tnd Wastes." EPA Environmental Monitoring and Support Laboratory, Cincinnati, OH 45268 (EPA-600/4-79-020).
-/wmu» owm o, /«.«. wwu. .- .. - 7 — —M* if* Materials, 1961 Race Street Philadelphia. PA 19103.
•^SdanTMethodaTor thV&uvninabon of Water and Wasteiater." 16th edition. American Public Health Association. American Water Works Association. Water
Inoroanic Substances in Water and Fluvial Sediments." techniques of Water-Resources Investigations ot the U.S. Geological
85-495. Available from Open-Fee Services Section, Western Dietribubon Branch. U.S. Geotogeal Survey. MS 306
Form WeWWG/5880. p. 5. 1985. Orion Research. Inc.. Cambridge, MA.
td Pleama Atomc Emiaeion Anatysia of Dnnking Water." Append* to Method 200 1. March, 1967. U.S. EPA, Environmental Monitoring
>2fi&
to each 100 mL of standard* and sample* is required before analyse
I. add 2 mL of 30% H.OI for each 100 mL of standard.
Ftoers in Water." EPA-600/4-63-043. September 1983, U.S. EPA. Environmental Research Laboratory.
Method for the Determination of Nitrite/Nitrate in Water Using Single Column Ion Chromatography." Method B-1011. MBSpore Corporation.
romatognpoy Dtvwon, 3X Maple Street MiKord, MA 01757.
" For approved analytical procedures for metals, the technique applicable to total metals must be used.
(2) Analyses for arsenic shall be
conducted using the following methods:
Method * 206.2. Atomic Absorption
Furnace Technique; or Method l 206.3,
or Method 4 D2972-78B. or Method »
301.A VTJ. pp. 159-162. or Method s I-
1062-78. pp. 61-63. Atomic Absorption-
Gaseous Hydride: or Method l 206.4. or
Method « LV2972-78A. or Method * 404-
METHOOOLOOY FOR FLUORIDE
A and 404-B(4), Spectrophotometric.
Silver Diethyl-dithiocarbamate.
(3) Analyses for fluoride shall be
conducted using the following methods-
CotoriroeWc SPADNS, with (
Automated Afearln fluoride 1
Automated ton »elect)ve eiei
Methodology
9lua, w«h dbalation (comptoone)
Reference (Method No.) '
EPA«
340.1
34O.2
340.3
ASTM"
D117»-72A
01 179-728
SM>
43 A and C
4138
413 E
Other
129-71W*
380-75WE'
* ,,I«_M.__^ -* *^._ - t « L t_ _• m-j —i u^.^.. « CL.A e^A.^m^*.**j ii. ^lahMfam Mv4 Anwt l Btvratnrv cl^neinneM. Ohio 45248 (EPA-600/4-79-020),
• iwwioaB w \*nmmcm Pfmrrwm at rvmmm tvu rrca^avm, &rr-» iwrveiwi •>*«•••.• rns^»w>»v ^»— - -r ^ — - -» — —— * - —-— _rr: .*. ., _^_._: ^--^j.. »-. tnj-t
March 1963. AvataCXe from OflDIFHibscaSone, CERl. EPA, CmdrmaH, Ohio 45268, For approved analytical procedures tor meta*. the technique applicable to total
metal* must be used.
• [Reeerved]
of ASTM Standard*.
tandaro., pert 31 Water. American Society for Tetfng and! Martriata, 1918 R*"S*wet.
• "Stanoert Method* tor the Eorninaton of Water and Waetewatar." 18th EdHton. American Pubtc Heslth Asaooalton.
. M^hod - 129-71W." T«=r«lcon IndurtrW 8ya«m , Tsnytewi.
' "Ftoonde h Water and Waetewater." Technfcon InduMrW Sytema. Tarrytown. New York 10681 . February 1978.
Water Works
York 10691.
197Z
(4) Sample collection for asbestos.
barium, cadmium, chromium, fluoride.
mercury, nitrate, nitrite, and selenium
under this section shall be conducted container, and maximum holding time
using the sample preservation. procedures specified in the table below:
Contaminent
Fhjonde
Pieueivatlve '
COOI.4-C
Cone UNO* to pH <1 '
Cone HNOi to pH <2_
Container1
PorQ
PorQ
PorQ
PorQ
PorQ
Time'
6 mm *ha.
6 month*.
6 month*.
1 month.
< "MrtSxxb of duaucx! AjulyiU of Wil*r and
WatlM." EPA EnviroomenUl Momtortoj and
Sur^"- Lc.ba-slory. Ctnctenttl. Ohio «S2« "S'A-
eC»'4-r»-flQO). VUrci :9T». AvtlUWt froai ORD
FMtuciUoCJ. CEK1 EPA. Oocinaitt Ohio 41286. For
IytloJ proc*dure» for m*Ul*. tfa*
ippuc*bU (o totaJ mctalj mu*t b* oied
i •'SuuuUrd M»tbod« for tin Examination ot
Water tad Wut*w«t*r," 16th Edition, American
Public KMltfe AwocUtton. ABMrican Water Works
AModatloa. Wtter Pollution Control Ftd*r*aon.
1965.
• Technique* of Wttar-IU»ourc*s Iavt»Uj«tion of
th« United SUtM Cwlofiaa Survey. Chtptar A-l.
"MtthooU for Detcrminanae of Inorjanlc
Subctano* la Wntsr and Fluvial Sedimmts," Book
8,1979. Slodt #014-OCrl-CBir7-a. ATalUbk tram
Superintendent of Docnnants. UA Govmuoem
Prinnnt OfSce. Wathinftoa. DC 20*01.
« Annu»l Book of ASTM Standard*, part « Wtltt
American Society for Tuttna and Materials. 191t
Raca Street Ptillarlerphla, Pcmuyhranla 1B10J.
-------
Federal Register / Vol. 56. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations
3583
Contaminant
Mercury
Nitrate:
Chlorinated ..
Non-chlonnated . : ~-
Nitrite •*-
Selenium —
Cooe H.SO. tO-pH
,, Cool. 4 'C.. ,:....
Preservative '
<2
i Contamor •
: G
i p
P Of G
! P or G
! P or G
....* ; P or G
.. rK.nn.nn It In tfM llhOratOTV
Time'
28 days.
i •> days.
28 days.
14 days.
*fl hours.-
6 months.
1
Upon, recap
snocid txt addod to sampe.
' ' P - plasoc hard y soft: G = jiass. hard or soft.
' In til cases samples should oe an»i/z»d as soon »ter collecfion as possiDle.
(3} Analysis under this section shall
only be conducted by laboratories that
have received approval by EPA or the
State. To receive approval to conduct
analyses for asbestos, barium, cadmium,
chromium, fluoride, mercury, nitrate,
nitrite and selenium the laboratory must:
(i) Analyze Performance Evaluation
samples which include those substances
provided by EPA Environmental
Monitoring and Support Laboratory or
equivalent samples provided by the
State.
(ii) Achieve quantitative results on the
analyses that are within the following
acceptance limits:
Contaminant
Abestos
Barium
Cadmium
Cnrormjm
Fluoride
Marcury
Nttrate
Nitrate
Selcrvum
2 standard
ttatatic*
±15% at
±20% al
±15% at
±10% at
i30% at
±10% at
±15% at
±20% at
Acceptance kmit
deviations bated on study
j.0.15 mg/l.
£ 0.002 mg/l.
^0.01 mg/l.
1 to 10 mg/l.
20.00OS mg/l.
^0.4 mg/l.
£0.4 mg/l.
£001 mg/l..
5. In § 141.24. paragraph (a) the
introductory text, paragraph (e), and
paragraph (f) are re .aed, and a new
paragraph (h) is added to read as
follows:
{141.24 r>9«rtic ctMtnicato othw than
tots) trthatomethane*, Mmpflng and
an*lyttc*l roquJretrxirrt*.
(a) Monitoring of endrin for purposes
of determining compliance with the
maximum contaminant level listed in
§ 141.12(a) shall be conducted as
follows:
• • • • •
(e) Analysis made to determine
compliance with the maximum
contaminant level for endrin in
5 141.12(a) shall be madr in accordance
with Method 50&, "Determination of
Chlorinated Pesticide* in Watei by Gail
Chroma tography with and Electron •
Capture Detector," in "Methods for the
Determination of Organic Compounds in
DrinHng Water," ORD Publications,
CERI, EPA/600/4-S8/039, December
1988.
• . « • •
(f) Analysis of the contaminants listed
in } 141.61(a) (9) through (18) for the
purpose of determining compliance with
the maximum contaminant level shall be
conducted as follows:
(1) Groundwater systems shall take a
minimum of one sample at every entry
point to the distribution system which is
representative of each well after
treatment (hereafter called a sampling
point). If conditions warrant the State
may designate additional sampling
points within the distribution system or
at the consumer's tap which more
accurately determines consumer
exposure. Each sample must be taken at
the same sampling point unless
conditions make another sampling point
more representative of each source or
treatment plant.
(2) Surface water systems shall take a
minimum of one sample at points in the
distribution system that are
representative of each source or at.each
entry point to the distribution system
after treatment (hereafter called a
sampling point). If conditions warrant
the State may designate additional
sampling points within the distribution
system or at the consumer's tap which
more accurately determines consumer
exposure. Each sample must be taken at
the same sampling point unless
conditions make another sampling point
more representative of each source,
treatment plant, or within the
distribution system.
Note: For purpo«e« of thi* paragraph.
surface water system* includa system* with •
combination of surface and ground surfaces.
(3) If the system draws water from
more than one source and the sources
are combined before distribution, the
system must sample at an entry point to'
the distribution system during periods of
normal operating condition* (i.e.. when
water representative of all sources is
being used).
(4) Each community and non-transient
non-community water system shall take
four consecutive quarterly sample* for
nnsed wnn '
each contaminant listed in 5 141.61(a) »
(9) through (18) during each compliance
period beginning in the compliance
periuu si-rting January 1,1993.
(5) Gru-indwater systems which'do
not detect one of the contaminants listed
in $ 141.61(a) (9) through (18) after
conducting the initial round of
monitoring required in paragraph (f)(4)
of this section shall take one sample
annually.
(6) If the initial monitoring for
contaminants listed in § 141.81(a) (9)
through (18) as allowed in paragraph
(0(18) of this section has been
completed by December 31.1992 and the
system did not detect any contaminant
listed in 5 141.61(a) (1) through (18) then
the system shall take one sample'
annually beginning January 1.1993.
After a minimum of three years of
annual sampling, the. State may allow
groundwater systems which have no
previous detection of any contaminant
listed in 1141.81(a) to take one sample
during each compliance period.
(7) Each community and non-transient
water system which does not detect a
contaminant listed in i 141.81(a) (1)
through (18) may apply to the State for a
waiver from the requirement of
paragraph (f)(4) and (f)(5) of this section
after completing the initial monitoring.
' (For the purposes of this section.
detection is defined as >0.0005 mg/l.) A
waiver shall b« effective for no more
than six years (two compliance periods).
(8) A State may grant a waiver after
evaluating the following factors):
(i) Knowledge of previous use
(including transport storage, or
disposal) of the contaminant within the
watershed or zone of influence of the
system. If a determination by the State
reveals no previous use of the
contaminant within the watershed or
zone of influence, a waiver may be
granted.
(ii) If previous use of the contaminant
is unknown or it ha* been used
previously, then the following factors
shall be used to determine whether a
waiver i* granted.
(A) Previous analytical results.
-------
3584 Federal Register / Vol. 56. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations
(B) The proximity of the system to
potential point or non-point source of
contamination. Point sources include
npills and leaks of chemicals at or near a
water treatment facility or at
manufacturing, distribution, or storage
facilities, or from hazardous and
municipal waste landfills and other
waste handling or treatment facilities.
(C) The environmental persistence
ar.d transport of the contaminants.
ID) The number of persons served by
the public water system and the
proximity of a smaller system to a larger
system.
(E) How well the water source is
pro'ec'ed against contamination such at
whether it is a surface or groundwater
system. Groundwater systems must
consider factors such as depth of the
well, the type of soil and wellhead
protection. Surface water systems must
consider watershed protection.
("•) A* a condition of the waiver a
system must take one sample at each
sampling point during the time the
waiver is effective (i.e.. one sample
during two compliance periods or six
years), and update its vulnerability
assessment considering the factors
listed in paragraph (f)(8) of this section.
Based on this vulnerability assessment
• the State must confirm that the system ii
non-vulnerable. If the State does not
make this reconfinnation within three
years of the initial determination, then
the waiver is invalidated and the system
is required to sample annually as
specified in paragraph (f)(S) of this
section.
(10) A surface water system which
does not detect a contaminant listed in
§ 141.81(8) (1) through (18) and is
determined by the S'ate to be non-
vulnermble usfng the criteria in
paragraph (f)(8) of thil section shall
monitor at the frequency specified by
the State (If any). Systems meeting this
criteria must be determined by the State
to be non-vulnerable based on a
vulnerability assessment during each
compliance period.
(11) If a contaminant listed in
1141.61(a) (9) through (18) is detected at
a level exceeding 0.0005 mg/1 in any
sample, then:
(i) The system must monitor quarterly
at each sampling point which resulted in
a detection.
(11) The State may decrease the
q'larterty monitoring requirement
specified in paragraph (0(11)0) ofthii
section provided it haa determined that
the system is reliably and consistently
below lha maximum contaminant level
In no ca« shall the State make this
ce'.enainanon unless a groundwater
system takss a minimum of two
quarterly samples and a surface water
system takes a minimum of four
quarterly samples.
(iii) If the State determines that the
system is reliably and consistently
below the MCL the State may allow the
system to monitor annually. Systems
which monitor annually must monitor
during the quarter(s) which previously
yielded the highest analytical result.
(iv) Systems which have three
consecutive annual samples with no
detection of a contaminant may apply to
the State for a waiver as specified in
paragraph (0(7) of this section. .
(v) [Reserved]
(12) Systems which violate the
requirements of § 141.61(a) (9) through
(18) as determined by paragraph (0(16)
of this section must monitor quarterly.
After a minimum of four quarterly .
samples shows the system U in
compliance as specified in paragraph
(0(18) of thi* section, and the State
determines that the system is reliably
and consistently below the maximum
contaminant level the system may
monitor at the frequency'and time
specified in paragraph (OlllX'") of *"
section.
(13) The State may require a
confirmation sample for positive or
negative results. If a confirmation
sample is required by the State, the
result must be averaged with the first
sampling result and the average is used
for the compliance determination as
specified by paragraph (0(16) of this
section. States have discretion to delete
results of obvious sampling errors from
this calculation.
(14) The State may reduce the total
number of samples a system must
analyze by allowing ths use of
compositing. Composite samples from a
maximum of five sampling points are
allowed. Compositing of samples must
be done in the laboratory and analyzed
within 14 days of sample collection.
(i) If the concentration :ni the
composite sample is ;> 0.0005 mg/1 for
any contaminant listed in § 141.61(a),
then a follow-up sample must be taken
in analyzed within 14 days from each
sampling point included in the
composite.
(ii) If duplicates of the original sample
taken from each sampling point used in
the composite are available, the system
may use these instead of resampling.
The duplicate must be analyzed and the
results reported to the State within 14
days of Collection.
(iii) If the population served by the
system is >3 JOO persons, then
compositing may only be permitted by
by the State at sampling points within a
single system. In systems serving O.300
person*, the State may permit
compositing among different systems
provided the 5-sample limit is
maintained.
(iv) Compositing samples prior to GC
analysis.
(A) Add 5 ml or equal larger amounts
of each sample (up to 5 samples are
allowed) to a 25 ml glass synnge.
•Special precautions must be made to
maintain zero headspace in the syringe.
(B) The samples must be cooled at 4*
C during this step to minimize
volatilization losses.
(C) Mix well and draw out a 5-ml
aliquot for analysis.
(D) Follow sample introduction,
purging, and desorption steps described
in the method.
(E) If less than five samples are used
for compositing, a proportionately small
syringe may be used.
(v) Compositing samples prior to GC/
MS analysis.
(A) Inject 5-ml or equal larger
amounts of each aqueous sample (up to
5 samples are allowed) into a 25-rol
purging device using the sample
introduction technique described in the
method.
(B) The total volume of the sample m
the purging device must be 25 ml.
(C) Purge and desorb as described in
the method. .
(15) Compliance with J 141.61 (a) (9)
through (IB) shall be determined based
on the analytical results obtained at
each sampling point
(i) For oystems which are conducting
monitoring at a frequency greater than
annual, compliance is determined by a
running annual average of all samples
taken at each sampling point If the
annual average of any sampling point is
greater than the MCL. then the system is
out of compliance. If the .initial sample
or a subsequent sample would cause the
annual average to be exceeded, then the
system is out of compliance
immediately. Any samples below the
detection limit shall be calculated as
zero for purposes of determining the
annual average.
(ii) If monitoring is conducted
annually, or less frequently, the system
is out of compliance if the level of i
contaminant at any sampling point is
greater than the MCL. If a confirmation
sample is required by the State, the
determination of compliance will be
based on the average of two samples.
(iii) If a public water system has a
distribution system separable from other
parts of the distribution system with no
interconnections, the State may allow
the system to give public notice to only
that area served by that portion of the
system which it out of compliance.
(10) Analysis for the contaminants
listed in 1141.61(a) (9) through (18) shall
-------
Federal RegUter / Vol. 56. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations
3585
be conducted using the following EPA
methods or their equivalent as approved
by EPA. These methods are contained in
"Methods for the Determination of
Organic Compounds in Drinking Water",
ORD Publications. CERi EPA/600/4-83/
039, December 1988. These documents
are available fr m the Natural
Technical Information Service (NTIS),
U.S. Department of Commerce. S285 Port
Royal Road. Springfield. Virginia 22181.
The toll-free number is 800-336-4700. •
(i) Method 502.1. "Volatile
Halogenated Organic Chemicals in
Water by Purge and Trap Gas
Chromatography."
(ii) Method 502.2. "Volatile Organic
Compounds in Water by Purge and Trap
Capillary Column Gas Chromatography
with Photoion'zation and Electrolytic
Conductivity Detectors in Series." .
(iii) Method 503.1. "Volatile Aromatic
and L'nsaturated Organic Compounds in
Water by Purge and Trap Gas
Chromatography."
(iv) Method 524.1. "Measurement of
Purgeable Organic Compounds in Water
by Purged Column Gas
Chromatography/Mass Spectrometry."
(v) Method 524.2. "Measurement of
Purgeable Organic Compounds in Water
by Capillary Column Gas
Chromatography/Mass Spectrometry." '
(17) Analysis under this section shall
only be conducted by laboratories that
have received approval by EPA or the
State according to the following
conditions:
(i) To receive conditional approval to
conduct analyses for the contaminants
in } 141.61(a) (9) through (18) the
laboratory must:
(A) Analyze Performance Evaluation
samples which include these substances
provided by EPA Environmental
Monitoring and Support Laboratory or
equivalent samples provided by the
State.
(B) Achieve the quantitative .
acceptance limits under paragraphs
(fKl8)(i) (C) and (D) of thi» section for at
least 80 percent of the regulated organic
chemicals listed in f 141.61(a) (2)
through (18).
(C) Achieve quantitative results on
the analyses perormed under paragraph
(0(18)(i)(A) of this section that are
within ±20 percent of the actual amount
of the substances in the Performance
Evaluation sample when the actual
amount is greater than or equal to 0.010
mg/1. •
(D) Achieve quantitative results on
the analyses performed under paragraph
(f)(18)(i)(A) of this section that are
within ±40 percent of the actual amount
of Lhe substances in the Performance
Evaluation sample when the actual
amount is less than 0.010 ing/I.
(E) Achieve a method detection limit
of 0.0005 mg/1. according to the
procedures in Appendix B of part 138 of
this chapter.
(F] Be currently approved by EPA or
the State for the analyses of
trihalomethanes under 8 141.30.
(ii) [Reserved]
(18) States may allow the use of
monitoring data collected after January
1.1988 required under section 1445 of
the Act for purposes of monitoring
compliance. If the data are generally
consistent with the other requirements
in this section, the State may use those
data (i.e., a single sample rather than
four quarterly samples) to satisfy the
initial monitoring requirement of
paragraph (0(4) of this section.
(19) States may increase required
monitoring where necessary to detect
variations within the system.
(20) Each approved laboratory must
determine the method detection limit
(MDL), as defined in Appendix B to Part
138 of this chapter, at which it is capable
of detecting VOCs. The acceptable MDL
is 0.0005 mg/1. This concentration is the
detection concentration for purposes of
this section.
(21) Each public water system shall
monitor at the time designated by the
State within each compliance period.
• * * • •
(h) Analysis of the contaminants
listed in § 141.61(c) for the purposes of
determining compliance with the
maximum contaminant level shall be
conducted as follows:
(1) Groundwater systems shall take a
minimum of one sample at every entry
point to the distribution system which is
representative of each well after
treatment (hereafter called a sampling
point). Each sample must be taken at the
same sampling point unless conditions
make another sampling point more
representative of each source or
treatment plant.
(2) Surface water systems shall take a
minimum of one sample at points in the
distribution system that are
representative of each source or at each
entry point to the distribution system
after treatment (hereafter called a
sampling point). Each sample must be
taken at the lame sampling point unless
conditions make another sampling point
more representative of each source or
treatment plant.
NoU: For purpose* of thii paragraph.
•urface water syitemj include iystemj with •
combination of lurface and ground tource*.
(3) If the system draws water from
more than one tource and the sources
are combined before distribution, the
system must sample at an entry point to
the distribution system during periods of
normal operating conditions (i.e.. when
water representative of all sources is
being used).
(4) Monitoring frequency:
(i) Each community and non-transient
non-community water system shall take
four consecutive quarterly samples for
each contaminant listed in { - n.61(c)
during each compliance period
beginning with the compliance period
starting January 1.1993.
(ii) Systems serving more than 3.300
persons which do not detect a
contaminant in the initial compliance *•
period may reduce the sampling
frequency to a minimum of two
quarterly samples in one year during
each repeat compliance period.
(iii) Systems serving less than or equal
to 3.300 persons which do not detect a
contaminant in the initial compliance
period may reduce the sampling
frequency to a minimum of one sample
during each repeat compliance period.
(5) Each community and non-transient
water system may apply to the State for
a waiver from the requirement of
paragraph (h){4) of this section. A
system must reapply for a waiver for
each compliance period.
(6) A State may grant a waiver after
evaluating the following factorfs):
Knowledge of previous une (including
transport, storage, or disposal) of the
contaminant within the watershed or
zone of influence of the system. If a
determination by the State reveals no
previous use of the contaminant within
the watershed or zone of influence, a
waiver may be granted. If previous use
of the contaminant is unknown or it has
been used previously, then the following
factor* shall be used to determine
whether a waiver ii granted.
(i) Previous analytical results.
(ii) The proximity of the system to a
potential point or no.-.-pomt source of
contamination. Point sources include
spills and leaks of chemicals at or near a
water treatment facility or at
manufacturing, distribution, or storage
facilities, or from hazardous and
municipal waste landfill* and other
waste handling or treatment facilities
Non-point sources include the use of
pesticides to control insect and weed
pests on agricultural areas, forest lands,
home and gardens, and other land
application uses.
(iii) The environmental persistence
and transport of the pesticide or PCBs.
(ii) How well the water source is
protected against contamination due to
such factors an depth of the well and the
type of soil and the integrity of the well
casing.
(v) Elevated nitrate levels et the water
supply source.
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3588 Federal Reg»ter / Vol. 56. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations
(vi) Use of PCBs in equipment used in
the production, storage, or distribution
of water (i.e.. PCBs used in pumpi.
transformers, etc.).
(7) If an organic contaminant listed in
5 U1.61(c) is detected (as defined by
paragraph (h)(18) of this section) in any
sample, ihen:
(i) Each system must monitor
quarterly at each sampling point which
resulted in a detection.
(ii) The State may decrease the
quarterly monitoring requirement
specified in paragraph (h)(7)(i) of this
section provided it has determined that
the system la reliably and consistently
below the maximum contaminant level.
In no case shall the State make this
determination unless a groundwater
system tikes a mir""""™ of two
quarterly samples and a surface water
system takes a minimum of four
quarterly samples.
(iii) After the State determines the
system is reliably and consistently
below the maximum contaminant level
the State may allow the system to'
monitor annually. Systems which
monitor annually must monitor during
the quarter that previously yielded the
highest analytical result
(iv) Systems which have 3 consecutive
annual samples with no detection of a
contaminant may apply to the S«ite for
a waiver as specified in paragraph (h)(6)
of this section.
(v) If monitoring results in detection of
one or more of certain related
contaminants (aldicarb. aldicarb
aulfone. akUcarb sulfoxid* and
heplachlor. heptachlor epoxide), then
subsequent monitoring shall analyze for
all related contaminants.
(8) Systems which violate the
requirements of { 141.81(c) as
determined by paragraph (h){12) of this
section must monitor quarterly. After a
maximum of four quarterly samples
show the system is in compliance and
the State determines the system Is
reliably and consistendy below th*
MCL as specified in paragraph (h)(ll) of.
this section, the system shall monitor at
the frequency specified in p*r«graph
(h)(7)(m) of this section.
(9) The Slate may require a
confirmation sample for positive or
negative results. If a confirmation
sample is required by th« State, the
result must be averaged with the first
sampling result and the average used foe
the compliance determination as
spec.fied by paragraph (h)(ll) of this
section. States have discretion to delete
retulU of obvious sampling errors from
tius calculation.
(10) The State may reduce the total
r.ur-ber of sample* a system must
or.a.yst t«> allowing the use of
compositing. Composite samples from a
maximum of five sampling points are
allowed. Compositing of samples must
be done in the laboratory and analyzed
within 14 days of sample collections.
. (i) If the concentration in the
composite sample detects one or more
contarranants listed in $ 141.Bl[c). then a
follow-up sample must be taken and
analyzed within 14 days from each
sampling point included in the
composite.
(ii) If duplicates of the original sample
taken from each sampling point used in
the composite are available, the system
may use these duplicate* instead of
resampling. The duplicate must be
analyzed and the results reported to the
State within 14 days of collection.
{iii) If the population served by the
system is > 3.300 persons, then
compositing may only be permitted by
the State at sampling points within a
single system. In systems ser-ing O.300
persons, the State may pennK
compositing among different systems
provided the S-sample limit is
maintained.
(11) Compliance with 1141.61{c) shall
be determined based on the analytical
results obtained at each sampling point
(i) For systems which are conducting
monitoring at a frequency greater than
annual, compliance is determined by a
nmning annual average of all samples
taken at each sampling point If th»
annual average of any sampling point is
greater than the MO, then the systam is
out of compliance. If the initial sample
or a subsequent sample would cause the
annual average to be exceeded, then the
system is out of compliance
'immediately. Any sample* below the
detection "mit ohall be calculated u
zero for purposes of determining the
annual average.
(ii] If monitoring it conducted
annually, or less frequently, the system
is out of compliance if the level of a
contaminant at any sampling point i*
greater than the MCL. If a confirmation
sample is required by the State, the
determination of compliance will be
based on the average of two sample*.
(iii) If a public water system has a
distribution system separable from other
parts of the distribution system with no
interconnections, the State may allow
the system to give public notice to only
that portion of the system which is out
of compliance.
(12) Analysis for the contaminant*
listed m f 141.61(c) shall be conducted
using the following EPA methods or
their equivalent a* approved by EPA.
These methods are contained in
"Methods for the Determination of
Organic Compound* in Drinking Water,"
ORD Publications, CERI, EPA/800/4-88/
039, December 1988. These documents
are available from the National
Technical Information Service (NTIS),
U.S. Department of Commerce, 5285 Port
Royal Road, Springfield. Virginia 22181.
The toll-free number is 1-800-336-4700.
(i) Method 5O4. "1.2-Dibromoethane
(EDB) and 1.2-Dibromo-3-chloropropane
(DBCP) in Water by Microextraction
and Gas Chromatography." Method 504
can be used to meaure
dibromochloropropane (DBCP) and
ethylene dibromide (EDB).
(ii) Method 505. "Analysis of
Organohalide Pesticides and
Commercial Polychlorinated Biphenyl
Product* (Aroclors) in Water by
Microextraction and Gas
Chromatography." Method 505 can be
used to measure alachlor, atrazine,
chlordane, heptachlor. heptaohlor
epoxide, lindane, methoxychlor, and
toxaphene. Method 505 can be used as a
screen for PCBi.
(iii) Method 507, "Determination of
Nitrogen- and Phosphorus-Containing
Pesticides ia Ground Water by Gas
Chromatography with a Nitrogen-
Phosphoru* Detector." Method 507 can
be u*ed to measure alachlor and
atrazine.
(iv) Method 508, "Determination of
Chlorinated Pesticides in Water by Gas
Chromatography with on Electron
Capture Detector." Method 508 can be
used to measure chlordane, heptachlor,
heptachlor epoxide, lindane and
methoxychlor. Method 508 can be used
as a screen for PCS*.
(v) Method 508A, "Screening for
Polychlorinated Biphenyl* by
Perchlorii.^tion mod Gas
Chromatography." Method 506A is used
to quantitata PCS* as
decachlorobiphenyi if detected m
Methods 508 or 508.
(vi) Method 515.1. "Determination of
Chlorinated Acid* in Water byG««
'Chromatography with an Electron
Capture Detector." Method 515.1 can be
used to measure 2.4-D, M.5-TP (Silvex)
and pentachlorophenoL
(vii) Method 525. "Determination of
Organic Compound* in Drinking Water
by Liquid-Solid Extraction and Capillary
Column G*s Chrom«togr«phy/Ma*«
Sptctrometey." Method 525 can be used
to measure atachlor, atrazme, chlordane,
heptachlor. heptachlor epoxide, lindane,
methoxychlor. and pentachlorophenoL
(viii) Method 531.1. "Measurement of
N-Methyl Carbamoyloximes and N-
Methyl Carbamates in Water by Direct
Aqueous Infection HPLC with Port-
Column Derivatization." Method 531.1
can b« u»«d to measure aldicarb,
aldicarb sutfoxide, aJdicarb sulfone, and
carbofuran.
-------
Federal R»g»t«r / Vol. 56, No. 20 / Wednesday, January 30. 1991 / Roles and Regulations
(13) Analysis for PCBs thdl be
conducted ai follows; •
(i) Each system which monitors for
PCBs shall analyze eack sample using
either Method 505 or Method 506 (see
paragraph (hK13) of this section).
(ii) If PCBs (as one of seven Aroclors)
are detected (as designated in this
paragraph) ia any sample analyzed
using Methods 305 or 508. the system
shall reanalyze the sample using Method
508A to quantitate PCBa (as
decacHorobiphenyl).
DatecSon limft
Arodor
ir)ifl ..— -
1221
1232
1 242 ...-__.
12*8
1254 . _ _ _
1260
DvtocM*
fenumg/f)
oxcocs
0.02
o.ooos
0.0003
0.0001
0.0001
0.0002
(iii) Compliance with the FOB MCL
shall be determined based upon the
quantitative results of analyses using
Method SOaA.
(14) If monitoring data collected after
January L 1980, are geaerally consistent
with the requirement* ol i 141.24{h),
thea th« S4aie say alJow systems to use
that data to satisfy tbe monitoring
requirement for tbe initial cempliaace
period beginning January 1,1993.
(15) The SUrU ouy i*creas« the
required meaiisriog frequency, where
necessary, to deUct vanaa'oB£ within
the tys-tan fe^n fkictu«tioo« in
conceatrsUfcta due ts seasonal ate.
changes in water source).
(16) The State has tke authority to
determine coiapkatvce or initiate
enforcement action based upon
analyticel results amd other infermation
compiled by their sanctioned
representatives and agencies.
(17) Each public water system shall
monitor at me timi designated by the
State within each compliance period.
(16) Detection as used hi this
paragraph shaft be denned as greater
than or equol to the foBowing
concentrations for each contaminant.
Cootvacwt
AlacNor.
(mo/0
Atr*zn«
Ctrbokrvn
CMonasavs
itOeCP). ^
2.4^5 j
Etfr/ierw (Strom«)« (ED81 _ - i
"""""*'"' I'L'L'Z.'.J
0.0002
oeos
0006
oooe
0001
000S
.0002
.00002
-OO04
.00601
, ooox
ooeoz
Undtr* • ' .00002
Metnoxycmor - _., OOO1
Potychtoonated btph«nyl» (PCBs) |
(ti oec«c«oroe*XwV) ', 0001
P»nUchkxoph«"o» j 00004
Toxit>n«n«.— i .001
2.4.S-TP (Slvwi) - 4 .0001
6. In J 141.32. paragraph (aXl)(ni)(B) is
revised, paragraphs (<} (13). (14), (16),
(25), (26). (27], and (48) arc reserved and
paragraphs (e) (15), (17] through (24).
(28) through (45). and (47} through (52)
are added to read as follows:
} 141.32 Pu&lc nsttficalten.
(a) • • *
(I)'*'
(iii)
(B) Violation of ibe MCL for njtrate or
nitrite as defined in 1141.82 and
determined according to i 141.23(iX3).
* * e * •
(e) • • *
(13H*») [Reserved]
(15) Asbestos. The United States
Environsaental Protection Agency (EPA)
sets drinking water standard* and has
determined that asbestos fibers greater
than 10 micrometers in length arc a
health concern at certain levels of
exposure. Asbssios is a natarally
occurring mineral. Moat asbestos fibers
in drinking water ara leas than 10
microjaeters in length &sA occur ia
drinking water from aatmal eoujces «ad
from cor. oded asi>€sto»-csment pipes ia
the distribution system. Tha major UMJ
of asbestos were in the production of
cements, floor t3ea, paper products,
paint, and caulking; in tranfipoxtation-
related applications: and in the
production of textiles and plastics.
Asbestos wa* occe a popular insulating
and fire retaraent material Inhalatio*
studies have shown thai various forms
of asbestos have produced lung tumors
in laboratory animals. The availaJaU
information on tba risk of developing
gastrointestinal tract cancer associated
with the Lagestion of asbestos from
drinking water is limited- Inge*tion of
intermediate-range chrysotfle asbesto*
fibers greater than 10 micrometers ia
length is associated with causing benign
tuBQOT* in male rats. Chemicals (bat
cause cancer in laboratory animals also
may increase the risk of cancer in
humans vrbo are exposed over long
periods of time. EPA has set the drinking
water standard for asbestos art 7 mffiion
long fibers per liter to reduce the
potential risk of cancer or other adverse
health effects which have been observed
in laboratory animals. Drinking water
which meets th« EPA standard rs
with little to none of tin* risk
and should be considered safe with
respect to asbestos.
(16) [Reserved] .
(17) Cadmium. The United States
Environmental Protection Agency [EIV
sets drinking water standards and has
determined that cadmium is a health'
concern at certain levels of exposure.
Food and the smoking of tobacco are
common sources of g
-------
3538 Federal Register'/ Vol. 58, No; 20 / Wednesday. January 30. 1991 / Rules and Regulations-.
the animals are exposed at high levels
over their lifetimes. EPA has set the
dnnking water standard for mercury at
0.002 parts per million (ppm) to protec:
against the risk of these adverse health
effects, Dnnking water that meets the
EPA standard is associated with little to
none of this risk and is considered safe
with respect to mercury.
(20) Nitrate. The United States
Environmental Protection Agency (EPA)
Beta drinking water standards and has
determined that nitrate poses an acute •
health concern at certain levels of
exposure. Nitrate is used in fertilizer
and is found in sewage and wastes from
human and/or farm animals and
generally gets into drinking water from
those activities. Excessive levels of
nitrate in drinking water have caused
serious illness and sometimes death in
infants under six months of age. The
serious illness in infants is caused
because nitrate is converted to nitrite in
the body. Nitrite interferes with the
oxygen carrying capacity of the child's
blood. This is an acute disease in that
symptoms can develop rapidly in
infants. In most cases, health
deteriorates over a period of days.
Symptoms include shortness of breath
and blueness of the skin. Clearly, expert
medical advice should be sought
immediately if these symptoms occur.
The purpose of this notice is to
encourage parents and other responsible
parties to provide infants with an
alternate source of drinking water. Local
and State health authorities are the best
source for information concerning
alternate sources of drinking water for
infants. EPA has set the drinking water
standard at 10 parts per million (ppm)
for nitrate to protect against the risk of
these adverse effects. EPA has also set a
drinking water standard for nitrite at 1
ppm. To allow for the fact that the
toxiciry of nitrate and nitrite are
additive. EPA has also established a
standard for the sura of nitrate and
nitrite at 10 ppm. Drinking water that
meets the EPA standard is associated
with little to none of this risk and is
considered safe with respect to nitrate.
(21) Nitrite. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that nitrite poses an acute
health concern at certain levels of
exposure. This inorganic chemical is
used in fertilizers and is found in
sewage and wastes from humans and/or
farm animals and generally gets into
drinking water as a result of those
activities. While excessive levels of
nitrite in drinking water have not been
observed, other sources of nitrite have
caused serious illness and sometimes
death in infants under six months of age.
The serious illness in infants is caused
because nitrite interferes with the
oxygen carrying capacity of the child's
blood. This is an acute disease in that
symptoms can develop rapidly.
However, in most cases, health
deteriorates over a perirH "' Hays.
Symptoms include shortness of breath
and biueness of the skin. Clearly, expert
medical advice should be sought
immediately if these symptoms occur.
The purpose of this notice is to
encourage parents and other responsible
parties to provide infants with an
alternate source of drinking water. Local
and State health authorities are the best
source for information concerning
alternate sources of drinking water for
infants. EPA has set the drinking water
standard at 1 part per million (ppm) for
nitrite to protect against the risk of these
adverse effects. EPA has also set a
drinking water standard for nitrate
(converted to nitrite in humans) at 10
ppm and for the sum of nitrate and
nitrite at 10 ppm. Drinking water that
meets the EPA standard is associated
with little to none of this risk and is
considered safe with respect to nitrite.
(22) Selenium. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that selenium is a health
concern at certain high levels of
exposure. Selenium is also an essential
nutrient at low levels of exposure. This
inorganic chemical is found naturally in
food and soils and is used in electronics,
photocopy operations, the manufacture
of glass, chemicals, drugs, and as a
fungicide and a feed additive. In
humans, exposure to high levels of
selenium over a long period of time has
resulted in a number of adverse health
effects, including a loss of feeling and
control in the arms and legs. EPA ha*
set the drinking water standard for
selenium at 0.05 parts per million (ppm)
to protect against the risk of these
adverse health effects. Drinking water
that meets the EPA standard is
associated with little to none of this risk
and is considered safe with respect to
selenium.
(23) Acrylamide. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that acrylamide it a health
concern at certain levels of exposure.
Polymers made from acrylamide are
sometimes used to treat water supplies
to remove particulate contaminants.
Acrylamide has been shown to cause
cancer in laboratory animals such as
rats and mice when the animals are
exposed at high levels over their
lifetimes. Chemicals that cause cancer in
laboratory animals also may increase
the risk of cancer in humans who are
exposed over long periods of time.
Sufficiently large doses of acrylamide
are known to cause neurological injury.
EPA has set the drinking water standard
for acrylamide using a treatment
technique to reduce the risk of cancer jr
ether adverse health effects which have
been observed in laboratory animals.
This treatment technique limits the
amount of acrylamide in the polymer
and the amount of the polymer which
may be added to drinking water to
remove particulates. Drinking water
nystems which comply with this
treatment technique have little to no risk
and are considered safe with respect to
acrylamide. ,
(2) Alachlor. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that alachlor is a health
concern at certain levels of exposure.
This organic chemical is a widely used
pesticide. When soil and climatic
conditions are favorable, alachlor may
get into drinking water by runoff into
surface water or by leaching into ground
water. This chemical has been shown to
cause cancer in laboratory animali such
as rats and mice when the animals are
exposed at high levels over their
lifetimes. Chemicals that cause cancer in
laboratory animals also may increase
the risk of cancer in humans who are
exposed over long periods of time. EPA
has set the drinking water standard for
alachlor at 0.002 parts per million (ppm)
to reduce the risk of cancer or other
.adverse health effects which have been
observed in laboratory animals.
Drinking water that meets .this standard
is associated with little to none of this
risk and is considered safe with respect
to alachlor.
(25) -(27) [Reserved]
(28) Atrazina. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that atrazine is a health
concern at certain levels of exposure.
This organic chemical is • herbicide.
When soil and climatic conditions are
favorable, atrazine may get into drinking
water by runoff into surface water or by
leaching into ground water. Thi«
chemical has been shown to affect
offspring of rats and the heart of dog».
EPA has set the drinking water standard
for atrazine at 0.003 parts per million
(ppm) to protect against the risk of these
adverse health effects. Drinking water
that meet* the EPA s^ndard is
associated with little to nont of this risk
and is considered f fe wtih respect to
atrazine.
-------
Federal Register / Vol. 56, No. 20 / Wednesday. January 30. 1991 / Rules and Regulations 3583 .
(29) Carbofuran. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that carbofuran is a health
concern at certain levels of exposure.
This organic chemical is a pesticide.
When soil and climatic conditions are
favorable, carbofuran may get into
J.-mking water by runoff into surface
water or by leaching into ground water.
This chemical has been shown.to
d image the nervous and reproductive
systems of laboratory animals such as
rats and mice exposed at high levels
over theif lifetimes. Some humans who
were exposed to relatively large
amounts of this chemical during their
working careers also suffered damage to
the nervous system. Effects on the
nervous system are generally rapidly
reversible. EPA has set the drinking
wa'er standard for carbofuran at 0.04
parts per million (ppm) to protect
against the risk of these adverse health
effects. Drinking water that meets the •
EFA standard is associated with little to
r.-one of this risk and is considered safe
with respect to carbofuran.
(30) Chlordane. The United States
Environmental Protection Agency (EPA
sets drinking water standards and has
determined that chlordane is a health
concern at certain levels of exposure.
' This organic chemical is a pesticide
used control termites. Chlordane is not
very mobile in soils. It usually gets into
drinking water after application near
v% ater supply intakes or wells. This
chemical has been shown to cause
cancer in laboratory animals such as
rats and mice when the animals are
exposed at high levels over their -
lifetimes. Chemicals that cause cancer in
laboratory animals also may increase
the nsk of cancer in humans who are
exposed over long periods of time. EPA
has set the drinking water standard for
chlordane at 0.002 parts per million
'(ppm) to reduce the risk of cancer or
other adverse health effects which have
been observed in laboratory animals.
Dnnking water that meets the EPA
standard is associated with little to none
of this risk and is considered safe with
respect to chlordane.
(31) Dibromochloropropane (DBCP).
The United States Environmental
Protection Agency (EPA) sets drinking
water standards and has determined
that DBCP'is a health concern at certain
levels of exposure. This organic
chemical was once a popular pesticide.
When soil and climatic conditions are
favorable, dibromochioropropane may
get into drinking water by runoff into
surface water or by leaching into ground
water. This chemical has been shown to
-ause cancer in laboratory animals such
as rats and mice when the animals are
exposed at high levels over their
lifetimes. Chemicals that cause cancer in
laboratory animals also may increase
the risk of cancer in humans who are
exposed over long periods of time. EPA
has set the drinking water standard for
DBCP at 0.0002 parts per million (ppm)
to reduce the risk of cancer or other
adverse health effects which have been
observed in laboratory animals.
Drinking water that meets the EPA
standard is associated with little to none
of this risk and is considered safe with
respect to DBCP.
(32) o-Dichlorobenzene. The United
States Environmental Protection Agency
(EPA) sets drinking water standards and
has determined that o-dichlorobenzc..e
is a health concern at certain levels o.
exposure. This organic chemical is used
as a solvent in the production of
pesticides and dyes. It generally gets
into water by improper waste disposal.
This chemical has been shown to
damage the liver, kidney and the blood
cells of laboratory animals such as rats
and mice exposed to high levels during
their lifetimes. Some industrial workers
who were exposed to relatively large
amounts of this chemical during working
careers also suffered damage to the
liver, nervous system, and circulatory
system. EPA has set the drinking water
standard for b-dichlorobenzene at 0.8
parts per million (ppm) to protect
against the risk of these adverse health
effects. Drinking water that meets the
EPA standard is associated with little to
none of this risk and is considered safe
with respect to o-dichlorobenzene.
(33) cis-l,2-Dichloroethylene. The
United States Environmental Protection
Agency (EPA) establishes drinking
water standards and has determined
that cis-l,2-dichloroethylene is a health
concern at certain levels of exposure.
This organic chemical is used as a
solvent and intermediate in chemical
production. It generally gets into water
by improper waste disposal. This
chemical has been shown to damage the
liver, nervous system, and circulatory
system of laboratory animals such as
rats and mice when exposed at high
levels over their lifetimes. Some humans
who were exposed to relatively large
amounts of this chemical also suffered
damage to the nervous system. EPA has
set the drinking water standard for cis:
1,2-dichloroethylene at 0.07 parts per
million (ppm) to protect against the risk
of these adverse health effects. Drinking
water the meets that EPA standard is
associated with little to none of this risk
and is considered safe with respect to
cis-1.2-dichloroethylene.
(34) trans-1.2-DichIoroethyIe.ne. The
United States Environmental Protectior
Agency (EPA) establishes drinking
water standards and has determined
that trans-1.2-dichloroethy!ene is a
health concern at certain levels of
exposure. This organic chemical is use~
as a solvent and intermediate in
chemical production. It generally gets .
into water by improper waste disposal.
This chemical has been shown to
damage the liver, nervous system, and
the circulatory system of laboratory
animals such as rats and mice when
exposed-at high levels over the.r
lifetimes. Some humans who were
exposed to relatively large amounts of v
this chenucal also suffered damage to
the nervous system EPA has set
drinking water standard for trans-1.2-
dichloroeth.ylene at 0.1 parts per million
(ppm) to protect against the risk of these
adverse health effects. Drinking water
that meets the EPA standard is
associated with little to nona of this risk
and is considered safe with respect to
trans-1.2-dichloroethylene.
(35) 1,2-Dichloropropar.e. The United
States Environmental Protection Agency
(EPA) sets drinking water standards and
has determined that 1.2-dichloropropar.e
is a health concern at certain levels of
exposure. This organic chemical is used
as a solvent and pesticide. When soil
and climatic conditions are favorable.
1,2-dichloropropane may get into
drinking water by ruroff into surface
water or by leaching into ground water.
It may also get into drinking water
through improper waste disposal. This
chemical has been shown to cause
cancer in laboratory animals such as
rats and mice when the animals arc
exposed at high levels over their
lifetimes. Chemicals that cause cancer in
laboratory animals also may increase
the risk of cancer in humans who are
exposed over long periods of time. EPA
has set the drinking water standard for
1,2-dichloropropane at 0.005 parts per
million (ppm) to reduce the risk of
cancer or other adverse health effects
which have been observed in laboratory
animals. Drinking water that meets the
EPA standard is associated with little to
none of this risk and is considered safe
with respect to 1,2-dichloropropane.
(361 2.4-D. The United States
Environmental Protection Agency (EPA)
sets drinking water standard* and has
determined that. 2.4-D is a health
concern at certain levels of exposure.
This organic chemical is used as a
herbicide and to control algae in
reservoirs. When soil and climatic
conditions are favorable. 2.4-D may get
into drinking water by runoff into
surface w'ater or by leaching into ground
-------
J590
Federal Register / VoL 56. No. 20 / Wednesday, fanmary 30. 1991 / Rules and Regulations
water. Thii chemical has been ihown to
damage the liver and kidney of
laboratory animals »uch as rail exposed
at high leveli during their lifetimes.
Some humans who were exposed to
relatively large amounts of this chemical
also suffered damage to the nervous
system. EPA has set the drinking water
standard for 2.4-D at 0.07 parts per
million (ppm) to protect against the risk
of these adverse'health effects. Drinking
water that meets the EPA standard is
associated with little to none of this risk
and is considered safe with respect to •
2.4-D.
(37) Epichlorohydrin. The United
States Environmental Protection Agency
(EPA) sett drinking water standards and
has determined that epichlorohydrin is a
health concern at certain levels of
exposure. Polymers made from
epichlorohydrin are sometimes used in
the treatment of water supplies as a
flocculent to remove particulates.
Epichlorohydrin genera'ly gets into
drinking water by improper use of these
polymers. This chemical has been
shown to cause cancer in laboratory
animals such as rats and mice when the
animals are exposed at high levels over
their lifetimes. Chemicals that cause
cancer in laboratory animals also may
increase the risk of cancer in humans
who are exposed over long periods of
time. EPA has set the drinking water
standard for epichlorohydrin using a
treatment technique to reduce the risk of
cancer or other adverse health effects
which have been observed in laboratory
animals. This treatment technique limits
the amount of epichlorohydrin in the
polymer and the amount of the polymer
which may be add.d to drinking water
as a flocculent to remove particulates.
Drinking water systems which comply
with this treatment technique have little
to no dak and are considered safe with
respect to epichlorohydrin.
(38) Ethylbeiucne. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined ethylbenzene is a health
concern at certain levels of exposure. -
This organic chemical is a major
component of gasoline. It generally gets
into water by improper waste disposal
or leaking gasoline tanks. This chemical
has been shown to damage the kidney,
liver, and nervous system of laboratory
animals such as rats expoied to high
levels during their lifetimes. EPA has set
the drinking water standard for
ethylbenzene at 0.7 part per million
(ppm) to protect against the nsk of these
adverse health effects. Drinking water
that meets the EPA standard is
associated with little to none of this risk
and is considered safe with respect to
ethylbenzene.
(39) Ethylene dibromide (EDB). The
United States Environmental Protection
Agency (EPA) seta drinking water
standards and has determined that EDB
is a health concern at certain levels of
exposure. This organic chemical was
once a popular pesticide. When soil and
climatic conditions are favorable. EDB
may get into drinking water by runoff
into surface water or by leaching into
ground water. This chemical has been
shown to cause cancer in laboratory
animals such as rats and mice when the
animals are exposed at high levels over
their lifetimes. Chemicals that cause
cancer in laboratory animals also may
increase the risk of cancer in humans
who are exposed over long periods of
time. EPA has set the drinking water
standard for EDB at 0.00005 part per
million (ppm) to reduce the risk of
cancer or other adverse health effects
which have been observed in laboratory
animals. Drinking water that meets thif
standard is associated with little to none
of this risk and is considered safe with
respect to EDB.
(40) Heptachlor. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that heptachlor is a health
concern at certain levels of exposure.
This organic chemical was once a
popular pesticide. When soil and
climatic conditions an favorable,
heptachlor may get into drinking water
by runoff into surface water or by
leaching into ground water. This
chemical has been shown to caus«
cancer in laboratory animals such as
rats and mice when the animals ar%
exposed at high levels over their
lifetimes. Chemicals that cause cancer in
laboratory animals also may increase
the risk of cancer in humans wno are
exposed over long periods of time. EPA
has set the drinking water standards for
heptachlor at 0.0004 pert per million
(ppm) to reduce the risk of cancer or
other adverse health effects which have
been observed in laboratory animals.
Drinking water that meets this standard
is associated with hide to none of this
riik and is considered safe with respect
to heptachlor.
(41) Heptachlor epoxida. The United
States Environmental Protection Agency
(EPA) sets drinking water standards end
has de»~rmined that heptachlor epoxide
is a health concern at certain levels of
eposure. This organic chemical was
once a popular pesticide. When soil and
climatic conditions are favorable,
heptachlor expoxide may get into
drinking water by runoff into surface
water or by leaching into ground water.
This chemical has been shown to cause
cancer in laboratory animals such as
rats and mice when the animals are
exposed at high levels over their
lifetimes. Chemicals that cause cancer in
laboratory animals also may increase
the risk of cancer in humans who are
exposed over long periods of time. EPA
has set the drinking water standards f •
heptachlor epoxide at 0.0002 part per
rrJllion (ppm) to reduce the risk of
cancer or other adverse health effects
which have been observed in laboratory
animals. Drinking water that meets this
standard is associated with little to none
of this risk and is considered safe with
respect to heptachlor epoxide.
(42) Undone. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that lindane is a health
concern at certain levels of exposure.
This organic chemical is used as a
pesticide. When soil and climatic
conditions are favorable, lindane may
get into drinking w.ater by runoff into
surface water or by leaching into ground
water. This chemical has been shown to
damage the liver, kidney, nervous
system, and immune system of
laboratory animals such as rats, mice
and dogs exposed at high levels during
their lifetimes. Some humans who were
exposed to relatively large amounts of
this chemical also suffered damage to
the nervous system and circulatory
system. EPA has established the
drinking water standard for lindane at
0.0002 part per million (ppm) to protect
against the risk of these adverse health
effects. Drinking water that meets the
EPA standard is associe'ed with little to
none of this risk and is considered safe
with respect to lindane.
(43) Methoxycblor. The United States
Environmental Protection Ager.cy (EPA)
sets drinking water standards and has
determined that methoxychlor is a
health concern at certain levels of
exposure. This organic chemical is used
as a pesticide. When soil and climatic
conditions are favorable, methoxychlor
may get into drinking water by runoff
into surface water or by leaching into
ground water. This chemical has been
shown to damage the liver, kidney.
nervous oystcm, ami reproductive
system of laboratory animals such as
rats exposed at high levels during their
lifetimes. It has also been shown to
produce growth retardation hi rats. EPA
has set the drinking water standard for
methoxychlor at 0.04 part per million
(ppm) to protect agsJnst the risk cf theue
advene health effects. Drinking water
that meets the EPA standard is
associated wim tittle to none of this risk
-------
Federal Register / Vol. set. No. 20 /Wednesday. January 30. 1991 / Rules and Regulations
3591
and is considered safe with raspect to
methoxychlor.
(44) Monochlorobenzene. The United
States Environmental Protection Agency
(EPA) sets drinking water standards and
has determined that monochlorobenzene
is a health concern at certain levels of
exposure. This organic chemical is used
as a solvent. It generally gets into water
by improper waste disposal. This
chemical has been shown to damage the
liver, kidney and nervous system of
laboratory animals such as rats and
mice exposed to high levels during their
lifetimes. EPA has set the drinking water
standard for monochlorobenzene at 0.1
part per million (ppm) to protect against
the risk of these adverse health effects.
Drinking water that meets the EPA
standard is associated with little to none
of this risk and is considered safe with
respect to monochlorobenzene.
(45) Polychlorinated biphenyls
iPCBsj. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that polychlorinated
biphenyls [PCBsj are a health concern ad
certain levels of exposure. These
organic chemicals were once widely
used in electrical transformers and other
industrial equipment. They generally get
into drinking water by improper waste
disposal or leaking electrical industrial
equipment. This chemical has beer
shown to cause cancer in laboratory
animals such as rats and mice when the
animal* are exposed at high levels over
their lifetimes. Chemical* that cause
cancer in laboratory animals also may
increase the risk of cancer in humans
who are exoosed over long periods of
time'. EPA has set the drinking water
standard for PCBs at 0.0005 part per
million (ppm) to reduce the risk of
cancer or other adverse health effects
which have been observed in laboratory
animals. Drinking water that meets this
standard is associated with little to none
of this risk and is considered safe with
respect to PCBs.
(46) [Reserved]
(47) Styrene. The United States
ijwironmental Protection Agency (EPA)
sets drinking water standards and has
determined that Btyrene is a health
concern at certain levels of exposure.
This organic chemical Is commonly used
to make plastics and is sometimes a
component of resins used for drinking
water treatment. Styrene may get into
drinking water from improper waste
disposal. This chemical has been shown
to damage the Liver and nervoug:iystem
in laboratory animals when exposed at
high levels during their lifetimes. EPA
has »et the drinking water stands-rd for
styrene at 0.1 part per million (ppm) to
protect against the risk of these adverse
health effects. Drinking water that meets
the EPA standard is associated with
little to none of this risk and is
considered safe with respect to styrene.
(48) Tetrachloroethylene. The United
States Environmental Protection Agency
(EPA) sets drinking water standards and
has determined that tetrachloroethylene
is a health concern at certain levels of
exposure. This organic chemical has
been a popular solvent, particularly for
dry cleaning. It generally gets into
drinking water by improper waste
disposal. This chemical has been shown
to cause cancer in laboratory animals
such as rats and mice when the animals
are exposed at high level* over their
lifetimes. Chemicals that cause cancer in
laboratory animals also may increase
the risk of cancer in humans who are
exposed over long periods of time. EPA
has set the drinking water standard for
tetrachloroethylene at 0.005 part per.
million (ppm) to reduce the risk of
cancer or other adverse health effects
which have been observed in laboratory
animals. Drinking water that meets this
standard is associated with little to none
of this risk and is considered safe with
respect to tetrachloroethylene.
(49) Toluene. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that toluene is a health •
concern at certain levels of exposure.
This organic chemical is used as a
solvent and in the manufacture of
gasoline for airplanes. It generally gets
into water by improper waste disposal
or leaking underground storage tanks.
This chemical has been shown to
damage the kidney, nervous system, and
circulatory system of laboratory animals
such as rats and mice exposed to high
levels during their lifetimes. Some
industrial workers who were exposed to
relatively large amounts of this chemical
during 'working careers also suffered
damage to the liver, kidney and nervous
system. EPA has set the drinking water
standard for toluene at 1 part per million
(ppm) to protect against the risk of
adverse health effects. Drinking water
that meets the EPA standard is
associated with little to none of this risk
and is considered safe with respect to
toluene.
(50) Toxaphene. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that toxaphene is a health
concern at certain levels of exposure.
This organic chemical was once a
pesticide widely used on cotton, corn.
soybeans, pineapples and other crops.
When soil and climatic conditions are
favorable, toxaphene may get into
drinking water by runoff into surface
water or by leaching into ground water.
This chemical has been shown to cause
cancer in laboratory animals such as
rats and mice when the animals are"
exposed at high levels over their
lifetimes. Chemicals that cause cancer i"
laboratory animals also may increase
the risk of cancer in humans who are
exposed over long periods of time. EPA"
has set the drinking water standard for •
toxaphene at 0.003 part per million
(ppm) to reduce the risk of cancer or
other adverse health effects which have
been observed in laboratory animals.
Drinking water that meets this standard
is associated with little to none of this
risk and is considered safe" with respect *
to toxaphene.
(51) 2.4,c-TP. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that 2.4.5-TP is a health
concern at certain levels of exposure.
This organic chemical is used as a
herbicide. When soil and climatic
conditions are favorable. 2,4,5-TP may
get into drinking water by runoff into
surface water or by leaching into ground
water. This chemical has been shown to
damage the liver and kidney of
laboratory animals such as rats and
dogs exposed to high levels during their
lifetimes. Some industrial workers who
were exposed to relatively large
amounts of this chemical during working
careers also suffered damage to the
nervous system. EPA has set the
drinking water standard for 2.4.5-TP at
0.05 part per million (ppm) to protect
against the risk of these adverse health
effects. Drinking water that meets the
EPA standard is associated with little to
none of this risk and is considered safe
with respect to 2,4.5-TP.
(52) Xylenes. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that xylene is a health
concern at certain leveb of exposure.
This organic chemical is used in the
manufacture of gasoline for airplanes
and as a solvent for pesticides, and as a
cleaner and degreaser of metals. It
usually gets into water by improper
waste disposal. This chemical has been
shown to damage the liver, kidney and
nervous system of laboratory animals
such as rats and dogs exposed to high
levels during their lifetimes. Some
humans who were exposed to relatively
large amounts of this chemical also
suffered damage to the nervous system.
EPA has set the drinking water standard
for xylene at 10 parts per million (ppm)
to protect against the risk of these
adverse health effects. Drinking water
that meet* the EPA standard is
associated with little to none of this risk
-------
3592 Federal Register / Vol. 56. No. 20 / Wednesday. January 30. 1991 / Rules and Regulations
and is considered safe with respect to
xylene.
7. In i 141.40 the section heading is
revised and a new paragraph (n) is
added to read as follows:
§ 141.40 Special monitoring for (norg*njc
and organic chemical*.
• • • • •
•(n) Monitoring of the contaminants
listed in 1141.40(n) (11) and (12) shall be
conducted as follows:
(1) Each community arid non-
transient, non-commun,:iy watar system
shall take four consecutive quarterly
samples at each sampling point for each
contaminant listed in paragraph (n)(;i)
of this section and report the results to
tne State. Monitoring must be completed
by December 31.1995.
(2) Each community and non-transient
non-community water system shall take
one sample at each sampling point for
each contaminant listed in paragraph
(n)(12) of this section and r.'port the
results to the States. Monitoring must be
completed by December 31.1995.
(3) Each community and non-transient
non-community water system may apply
to the State for a waiver from the
requirements of paragraph (n) (l) and (2)
of this section.
(4) The State may grant a waiver for
the requirement of paragraph (n)(l) of
this section based on the criteria
specified in § 141.24(h)(6). The State
may grant a waiver from the
requirement of paragraph (n)(2) of this
section if previous analytical results
indicate contamination would not occur.
provided this data was collected after
January 1.1990.
(5) Groundwater systems shall take a
minimum of one sample at every entry
point to the distribution system which is
representative of each well after
treatment (hereafter called a sampling
point). Each sample must be taken at the
same sampling point unless conditions
make another sampling point more
representative of each source or
treatment plant.
(6) Surface water systems shall take a
minimum of one sample at points in the
distribution system that are
representative of each sourc* or at each
entry point to the distribution system
after treatment (hereafter .called a
sampling point). Each sample must be
taken at the same sampling point unless
conditions make another sampling point
more representative of each source or
Ues'jr.enl plant.
NoU- For purpo*ef of thii paragraph.
surface water lyitems include lyiiemi with •
cocbutnUon of gurface and ground tourcei.
(~\ If the system draws water from
•—'"": u»fer. one source and the sources
are combined before distribution, the
' system must sample at an entry point to
; the distribution system during periods of
normal operating conditions (i.e.. when
water representative of all sources is
| being used).
(8) The State may require a
confirmation sample for positive or
negative results.
(9) The State may reduce the total
number of samples a system must
analyze by allowing the use of
compositing. Composite samples from a
maximum of five sampling points are
allowed. Compositing of samples must
be done in the laboratory end the
composite sample must be analyzed
within 14 days of collection. If the
population served by the system is
> 3.300 persons, then compositing may
only be permitted by the State at
sampling points within a single system.
In systems serving £ 3.300 persons, the
State may permit compositing among
different systems provided the 5-sample
limit is maintained.
(10) Instead of performing the
monitoring required by this section, a
community water system or non-
transient non-community water system
serving fewer than 150 service
connections may send a letter to the
State stating that the system is available
for sampling. This letter must be sent to
the State by January 1.1994. The system
shall not send such samples to the State,
unless requested to do so by the State.
(11) List of Unregulated Organic
Contaminants:
Organic comarranents
AUrtn.....
BaexaXa)pyreoa
RutacMor
Cartaryf
Dalapon ,
CX(2-«0TytMxyt)ao1p«t«
Dreamt*
DWdrto
Dnoeeb
Oqjet _. _ .
Endoma* :.
Gtypnoaate
3-Hy2S
531.1
531 1
SC7 525
507.508,525
531.1
515 1
507 525
505 507 525
513
(12) List of Unregulated Inorganic
Contaminants:
Contaminant
i (i) Antinony...
I
I (») Beryllium...
(in)
fiv) Sjfate
-------
Fedatal RagiaUr / VoL 56. No. 20 / Wednesday. January 30. 1901 / Rules and Regulations 35S3
{ 141.51 Maximum contaminant )•«•(
goat* for Inorganic contaminant*.
(b) • • ••
Corumncnt
•MCU3 tmg/t)
(2) Aitwoto* 7 MHkon fiberVUtar
0ong«r thin
(3) [ReM»v»d]
(4) Cadrruuai 0005
(5) Chrtxmjn- 0,1
(6) btorcury 0.002
(7) Mtrmta 10 (a* Nitrogen).
(8) Nrtnt* t (at Nitroo»n).
(9) Tot* Nfram NiMa-
(10) S*«f«um OJ»
10. Section 141.00 ia revised to read aa
follows:
5 141.00 Ef1«ct1v« dates.
(a) The effective dates for $ 141.81 are
as follows:
(1) The effective date for paragraphs
(aK'l) through [a)(8) of S 141.61 is
January 9,1989.
(2) The effective date for paragraphs
(aft?) through (a)(l8) and (c)(lj through
(c)(18) of i 141.61 is July 30,1992.
(b) The effective dates for { 141.62 are
as follows:
(1) The effective date of paragraph
(b)(l) of 1141.62 is October 2.1987.
(2) The effective date for paragraphs
(b){2) and (b)(4) through (b}(10) of
$ 141.62 is July 30, 1992.
11. Section 141.61 is revised to read aa
follows:
{ 141.«1 Maximum contaminant tewta for
organic contaminant*,
{«) The following maximum
contaminant levels for organic
contaminants apply to community and
ansient non-community water
systems.
CAS Mo.
(1) 75-01-4
(2) 71-43-2 -
(3) 56-23-5 . - -
W1O7-QB-^2
(5) 79-0 !-•
(6) 105-45-7
(7) 75-35-4 . ,. ,
(8) 71-SM, ...._ _ - - - -
(9) l5*VS»-^2 - _ _ , - : —
(10) 7VB7-S - -
(1 1) 100 411 1 . . •
(12) 10IWO-7
(13) 9S-5D-1
(15) 127-1S-4
(16) 10S-SS^3 ... .
(17) 15fl-fiD~£
(18) 1 330-20-7 _ - ~.
/Xu^^M^^MH*
\JpniawTwlVTl
SVM cfrhTnia
Btfomu
Ij'SSrtorolSftlna* " ~"
1 1-OoMorOktny4*nt
1 g nil hl'iiiynyai'a
Ettntttnm
MoftjoMcNoO«ni»m
o fm lid mjaaniami
Stfftnt ,
T,wditoraa»»<»»
Tntffn^ ,
lran»-l 7-OK^croiHtyHTX .,
Xy4«n*t (total) • . r,,.. ,,^T r,,,
MCL
-------
3594 Federal Regbter /.Vol. 56. No, 20 / Wednesday. January 30. 1991 / Rules and Regulations
BAT FOB ORGANIC CONTAMINANTS LISTED IN SECTION 141.61 (a) AND (c)—Continued
CAS No.
03_72_f ,,.,„..,
127- 1 ft— 4
7t»S5-€
t330-2$-7 „
Cfwroca*
Styww .,„
245-TP In Table
1 - Actvatw)
2 -
3 - OSrecl end Datorp/j FKraton
4 •> Greoufar Acevaiacl Cartxxi
5 *• Ion EKC^wnub
6 - Dm* Sotarlng
7 - R«v««B9 O*mo«
8 - Corrosion Control
13. A new subpart K is addexi to part
141 to read as follows:
— Treatment T»chrt»^«»«
S»c.
141.110 General requiremenU.
141.111 Treatment t«chniques for
acrytamide and epichlorohydrin.
SuS^psrt K— Treatment TscJwtiqii** _
{141.110 Qanonl
The requirements of subpart K oi this
port constitute national primary drinking
water regulations, Thet« regulations
establish treatment techniques in lieu of
maximum contaminant levels for
specified contaminants.
{141.111 TrsetrosM iswtfiBJssa** for
ecrytemfda emd ep«U>tmuci»ditr>.
Each public water system must certify
annually in writing to the State (using
third party or manufacturer's
certification) that when acrylamid* and
epichlorohydrin are used in drinking
-------
Federal Register / Vol. 56. No. 20 / Wednesday, January 30. 1991 / Rules and-Regulations 3595
water systems, the combination (or
product) of dose and monomer level
does not exceed the levels specified as
follows:
Acrylaraide = O.OS% dosed at'l ppm (or
equivalent)
Epichlorohydrin=0.01% doied at 20 ppm (or
equivalent)
Certifications can rely on manufacturers
or third parties, as approved by the
State.
PART 142—NATIONAL PRIMARY
DRINKING WATER REGULATIONS
IMPLEMENTATION
1. The authority citation for part 142 ,
continues to read as follows:
Authority: 42 U.S.C. SOOg. 300g-l. 300g-2.
300g-3. 3008-4, 300g-5, 300g-0, 300H *nd
300J-9.
2. Section 142.14 is amended by
revising paragraph (a)(6). paragraph (c).
the introductory text to paragraph (d).
and paragraph (f); and by adding
paragraphs (d}(4) through (d}(7) to read
as follows:
§ 142.14 Records k«pt by SUM*.
(a)'*'
(6) Records of analysis for other than
microbiological contaminants (including
total colifonn. fecal coliform, and
.heterotrophic plate count), residual
disinfectant concentration, other
parameters necessary to determine
disinfection effectiveness (including
temperature and pH measurements),
and turbidity shall be retained for not
less than 12 years and shall include at
least the following information:
• * » * *
(o) Each State which has primary
enforcement responsibility shall
maintain current inventory information
for every public water system in the
State and shall retain inventory records.
of public water systems for not less than
12 years.
(d) Each State which hat primary
enforcement responsibility shall retain.
for not less than 12 yean, filet which
shall include for each such public water
system in the State:
• • • • •
(4) A record of the most recent
vulnerability determination, including
the monitoring results and other data
supporting the determination, the State's
findings based on the supporting data
and any additional bases for such
determination; except that it shall be
kept in perpetuity or until a more current
vulnerability determination has been
issued.
(5) A record of all current monitoring-
requirement* and the most recent
monitoring frequency decision
pertaining' to each contaminant,
including the monitoring results and
other data supporting the decision, the
State's findings based on the supporting
data and any additional bases for such
decision; except that the record shall be
kept in perpetuity or until a more recent
monitoring frequency decision has been
issued.
(6) A record of the most recent
asbestos repeat moi..ioring
determination, including the monitoring
results and other data supporting the
determination, the State's findings based
on the supporting data and any
additional bases for the determination ,
and the repeat monitoring frequency;
except that these records shall be
maintained in perpetuity or until a more
current repeat monitoring determination
has been issued.
(7) Records of annual certifications
received from systems pursuant to part
141, subpart K demonstrating the
system's compliance with, the treatment
techniques for acrylamide and/or
epichlorohydrin in { 14.111.
* • • * *
(f) Records required to be kept under
this section shall be available to the
Regional Administrator upon request.
The records required to be kept under
tliis section shall be maintained and
made available for public inspection by
the State, or, the State at its option may
require suppliers of water to make
available for public inspection those
records maintained in accordance with
$ 141.33
3. In 1 142.15 is amended by adding
new paragraph (c)(3) to read as follows:
§142.15 Reports by StfttM.
• • * * . *
(c) ' * '
(3) The results of monitoring for
unregulated contaminants shall b«
reported quarterly.
4. $ 142.16 is amended by reserving
paragraph (d) and by adding a new
paragraph (e) to read as follows:
}1411«
primacy r»qu8r»m«ot«.
(d) [Reserved]
(e) An application for approval of a
State program revision which adopts the
requirements specified in ii 141.23,
141.24, 141.32. 141.40, 141.61, 141.62. and
141.11 must contain the following (in
addition to the general primacy
requirements enumerated elsewhere in
this part including the requirement that
state regulations be at least as stringent
as the federal requirements):
(1) If a State chooses to issue waivers
from the monitoring requirements in
U 141.23, 141.24. and 141.40, the State
shall describe the procedures and
criteria which it will use to review
waiver applications and issue waiver
determinations.
(i) The procedures for each
contaminant or class of contamina its
shall include a description of:
(A) The waiver application
requirements; ;
^B) The State review process for 'use"
waivers and for "susceptibility '
waivers: and
(C] The State decision criteria.
including the factors that will be
considered in deciding to grant or deny
waivers. The decision criteria must «
include the factors specified in
i i 141.24(f)(8). 141.24(h)(8). and
141.40{n)(4).
(ii) The State musf specify the
monitoring data and other
documentation required to demonstrate
that the contaminant is eligible for a
"use" and/or "susceptibility" waiver.
(2) A plan for the initial monitoring
period within which the State will
assure that all systems complete the
required monitoring by the regulatory
deadlines;
(i) The plan must describe how
systems will be scheduled during the
initial monitoring period and
demonstrate that the analytical
workload on certified laboratories for
each of the three years has been taken
into account, to assure that the State's
plan will result in a high degree of
monitoring compliance and will be
updated as necessary,
(ii) The State must demonstrate that
the initial plan is enforceable under
State law.
S. Section 142.18 is added to subpart B
to read as follows:
$ 142.11 EPA review of State monitoring
dotwminrttona.
, (a).A Regional Administrator may
annul a State monitoring determination
for die types of determinations
identified in § 1141.23(b), 141.23(c).
141.24(f). 141.24{h). and 141.40(n) in
accordance with the procedures in
paragraph (b) of this section.
(b) When information available to a
Regional Administrator, such as the
results of an annual raviow, indicate a .
State determination fails to apply the
standards of the appitmtd State
program, he may propose to annul the
State monitoring determination by
sending the State and th« affected PWS
a draft Rescission Order. The draft order
shall:
(1) Identify the PWS, the State
determination, and the provisions at
issue;
-------
1
3596 Federtl Register / yoL 56. N.o. 20 / Wednesday, January 30. 1991 / Rule3 'and Regulations
(2) Explain why the State
determination ii not in compliance with
the State program and must be changed:
and
(3) Describe the action* and terms of
operation the PWS will be required to
implement.
(c) The State and PWS shall have 60
days to comment on the draft Rescission
Ordei.
(d) The Regional Administrator may
riot issue a Rescission Order to impose
conditions less stringent than those
imposed by the State.
(e) The Regional Administrator shall
also provide an opportunity for
comment upon the draft Rescission
Order, by
(1) Publishing a notice in a newspaper
in general circulation in communities
served by the affected system; and
(2) Providing 30 days for public
comment on the draft order.
(0 The State shall demonstrate that
the determination ia reasonable, based
on its approved State program,
(g) The Regional Administrator shall
decide within 120 days after issuance of
the draft Rescission Order to:
(1) Issue the Rescission Order as
drafted;
(2) Issue a modified Rescission Order.
of
(3) Cancel the Rescission Order.
(h) The Regional Administrator shall
set forth th« reasons for his decision,
including a responsiveness summary
addressing significant comments from
the Slate, the PWS and the public.
(i) The Regional Administrator shall
send a notice of his final decision to the
State, the PWS and all parties who
commented upon the draft Rescission
Order.
(j) The Rescission Order shaD remain
in effect until cancelled by the Regional
Administrator. The Regional
Administrator may cancel a Rescission
Order at «ny time, so long as h« notifies
those who commented on the draft-
order.
(k) The Regional Administrator may
not delegate the signature authority for a
final Rescission Order or the •
cancellation of an order.
(I) Violation of the action*, or terms of
operation, required by a Rescission
Order It a violation of the Sale Drinking
Water Act
6. Section 142.57 is revised to read as
follows:
H42.C7 Betted water, *<**-<*ue«, and
polnt-of-enlry da-rieec.
(a) A State may require a public water
ays ten to use bottled water, point-of-use
devices, or point-of-«nn-y device* as •
condition of granting an exemption from
the requirements of If 141.61 (a) and (c).
and ! 141.62 of this chapter.
(b) Public water system* using bottled
water as a condition of obtaining an
exemption from the requirements of
$ 5 141.61 (a) and (c) and § 141.52(h) of
this chapter must meet the requirement*
in I 142.62(g).
(c) Public water systems that use
point-of-use or point-of-entry devices a*
a condition for receiving an exemption
mu»t meet the requirement* in
7. Section 142.62 i* revised to
follow*:
5 1 42.62 Variance* and exemptta
organic and Inorganic chemical*,
(a) The Administrator, pursua
•ection 1415(a)flKA) of the Act
identifies the technologies listed
paragraphs fa)(l] through (a)(36
section as the best technology,
treatment technique*, or other a
available for achieving complia:
the maximum contaminant love
organic chemicals as listed in J
(a) and (c).
«—_
(1) Banzwi.* ,. ,.
(2) Carbon t»tr*cnkxW«
(5) para-Oict*xoberaena
(6) 1.1-0icfiloroettiytan*.._
(7) 1.1.1-Trirttaroefhane
(81 V*iy1 cMoada
(9) oa-l^-Ochkyoethylena...
(10) 1.2-Oehlorepropana
(11) Ethytoeroene
(12) Monochtoroeenzena
(13) o-Dichlorobenzane
(UlStyr.n.
(15) TetracMoroetnytane
(16) Toluene
(17) trane-1,2-Dichtoroethy-
lene.
(18)Xytonaa(toW)
(19) Atoentor
(20) Aidteartj
(21) Akicarti autfonde
(22) Aldfcart) aurfone
(23) Atrazine .'.
(24) Carboruran
(25) Chkxdane
(27)2.40 _ _ _.. .
(28) Ettiytane dUuueJe
(29) Haptacntor
(3O) H*p«i«
(36) 2^4,5-TP
reado*
nafrom
or
ntto
iereby
tin
) of this
lean*
ice with
* for
141.61
Beat avaffaMe
tachmiogMa
Padud
aaca&on
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Granular
activated
carbon
XXXKXXXXXXXXKXXXXXX XXXXXXXXX XXXXXXX
(b) The Administrator, piirsuanl to
section 1415(aJ(l)(A) of the Act hereby
identifies the following as the beat
technology, treatment techniques, or
other means available for achievin^
compliance with the maximum
contaminant levels for the inorganic
contaminants listed in {
BAT FOR INORGANIC COMPOUNDS LISTED
(N9t4l.62tb)
Chemical name
BAT(a)
AabaetO*..
B«num..
Cadmium
Chromium
Mercwy
Nitrate—
Nitrite
Seterwjm
2,3.8
5.6.7J
Z5.6.7
2 5.8 ».7
2 '. 4.8 »,7 '
5.7.9
5.7
1.2 *
1 BAT only if influent Hq concentration* <10 up/
* BAT for ntroobtn W only
' BAT tor Sotonum IV only
Key to BAT» in T«
2-Cc*gul«ic
-------
Federal Reggter / Vol. 56. No. 20 / .Wednesday, January 30, 1991 /Rules and Regulations 3597
(f) The State may require a public
water system to use bottled water.
point-of-use devices, point-of-entry
devices or other means as a condition of
granting a variance o* an exemption
from the requirements of 1141.61 (a)
and (c) ard J 141.62 to avoid an
unreasonable risk to health.
(g) Public water systems that use
bottled water as a condition for
receiving a variance or an exemption
from the requirements of J 141.81 (a) •
and (c) and § 141.62 must meet the
requirements specified in either
paragraph (g)(l) or (g}(2) and paragraph
(g)(3) of this section:
. 11) The Administrator or primacy
State must require and approve a
monitoring program for bottled water.
The public water system must develop
and put in place a monitoring program
that provides reasonable assurances .
that the bottled water meets all MCLs.
The public water system must monitor a
representative sample of the bottled
water for all contaminants regulated
under 5 141.61 (a) and (c) and 5 141.62
during the first three-month period thai
it supplies the bottled water to the
public, and annually thereafter. Results
of the monitoring program shall be
provided to the State annually.
(2) The public water system must
receive a certification from the bottled
water company that the bottled water
supplied has been taken from an
"approved source" as defined in 21 CFR
129.3(a); the bottled water company has
conducted monitoring in accordance
with 21 CFR 129.80(g) (1) through (3);
snd the bol.led water does not exceed
any MCLs or quality limits as set out in
21 CFR 103.C3,110, and 129. The public
water system shall provide the
certification to the State the first quarter
after it supplies bottled water and
annually thereafter. At the State's option
a public water system may satisfy the
requirements of this subsection if an
approved monitoring program is already
in place in another State.
(3) The public water system is fully
responsible for the provision of
sufficient quantities of bottled water to
every person supplied by the public
water system via door-to-door bottled
water delivery.
(h) Public water systems that use
point-of-use or point-of-entry devices as
a condition for obtaining a variance or
an exemption from NPDWRs must meet
the following requirements:
(1) It is the responsibility of the public
•vater system to operate and maintain
the point-of-use and/or point-of-entry
treatment system.
(2) Before point-of-use or point-of-
entry devices are installed, the public
water tystem must obtain the approval
of a monitoring plan which ensures that
the devices provide health protection
equivalent to that provided by central
water treatment.
(3) The public water system must
apply effective technology under a
State-approved plan. The
microbiological safety of the water must
be maintained at all times.
(4) The State must require adequate
certification of performance, field
testing, and. if not included in the
certification process, a rigorous
engineering design review of the point-
of-use and/or point-oi-entry devices.
(5) The design and application of the
point-of-use and/or point-of-eutry
devices must consider the potential for
increasing concentrations of
heterotrophic bacteria in water treated
with activated carbon. It may be
necessary to use frequent backwashing,
post-contactor disinfection, and
Heterotrophic Plate Count monitoring to
ensure that the microbiological safety of
the water is not compromised. ,
(6) The State must be assured that
buildings connected to the system have
sufficient point-of-use or point-of-entry
devices that are properly installed.
maintained, and monitored such that all
consumers .will be protected.
PART 143—NATIONAL SECONDARY
DRINKING WATER REGULATIONS
1. The authority citation for part 143
continues to read as follows:
Authority: 42 U.S.C. 300g-l(c), 300J-4- and
300J-9.
2. In § 143.3 the table is revised to
read as follows:
5 143.3 Secondary maximum contaminant
(•varis.
Contaminant
Lev*
Aluminum
CNond*
Cotof
Gonio«vTty ..........
Fkjonel* ..............
Foaming agent*.
Iron .......................
pH
S»v«r
Sonata
Total diaaorvarf
(TDS).
Zinc
sofei*
0.05 to 0.2 mg/1.
250ms/l.
15 cater units.
1.0 mg/1.
2.0 mg/l.
O.'j mg/1.
0.3 mg/1.
0.05 mg/1.
3 trtrejahoid otiot
number.
8.S-4.5.
0.1 mg/1.
250 mg/1.
500 mg/1.
5 mg/1.
§ 143.4 Monitoring.
* • • * •
(b) * ' '
(12) Aluminum—Method ' 202.1 .
Atomic Absorption Technique-Direct.
Aspiration: or Method 2 303C; or
Method s I-305i-84: or Method ' 202.2 '
Atomic Absorption-Graphite Furnace
Technique: or Method * 304': or Method *
200.7 Inductively-Coupled Plasma
Technique: or Method 8 200.8
Inductively Coupled Plasma-Mass
Spectrometry or Method * 200.9 Platforpi
Technique: or Method 7 3120B
Inductively-Coupled Plasma Technique.
(13) Silver—Method l 272.1 Atomic
Absorption Technique-Direct
Aspiration: or Method * 303 A or B; or
Method 3 1-3720-64: or Method ' 272.2
Atomic Absorption-Graphite Furnace
Technique: or Method * 304: or Method 4
200.7 Inductively-Coupled Plasma-
Technique; or Method * 200.8
Inductively-Coupled Plasma-Mass
Spectrdmetry; or Method • 200.9
Platform Technique: or Method T 312OB
Inductively-Coupled Plasma-Technique.
(FR Doc. 91-933 Filed 1-29-91; 8:45 am)
•tLUNO COM f540-W-U
3. Section 143.4 is amended by adding
paragraphs (b)(12) and (b)(13) to read ai
follows:
1 "Method! of Chemical Analysis of Water and
Wastes." EPA. Environmental Mom :onng and
'Systems Laboratory. Cincinnati. OH 45208. EPA
600/4-79-020. March. 1903. Available from ORO
Publication. CERL EPA. Cincinnati. OH 45268.
* "Standard Methodi for the Examination of
Water and Wattewater," 16th Ed.. American Public
Health Association. American Waterworki
Association, Water Pollution Control Federation.
IMS.
' "Methods for the Determination of Inorganic
Substance* m Water and Fluvial Sediments."
Technique* of Water-Resourcss Investigations of
the United States Geological Survey Books. Chapter
Al. 1985, Available from Open File Services
Section. Western Distribution Branch. U.S.
Geological Survey. Denver Federal Center. Denver.
CO 80255.
4 "Determination of Metal* nnd Trace Elements
by Inductively Coupled Plasma-Atomic Emission
Spectrometry." Method 200.7. version 3.1. Apnl.
1990, EPA. Environmental Monitoring and System*
Laboratory. Cincinnati. OH 45280.
• "Determination of and Trace Elements in Water
and Waste* by Inductively Coupled Plasma-Mas*
Spectrometry," Method 200.*, version 4.1. March.
1980, EPA. Environmental Monitorial and Systems
Laboratory. Cincinnati. OH 45288. Available from
ORD Publication. CERI. EPA. Cincinnati. OH 45266.
• "Determination of Metals .and Trace Elements
by Stabilized Temperature Graphite Furnace
Atomic Absorption Spectrometry," Method 200 9.
version 1.0, April 1980. EPA. Environmental
Monitorinj and Systems Laboratory. Cincinnati. OH
45208.
' "Standard Methods for tho Examination of
Water and Waitewatar." 18th ed.-. American Public
Health Association. American Waterworks
Association. Water Pollution Control Federstion.
lees.
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