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[Federal Register: January 22, 2001 (Volume 66, Number 14)]
[Rules and Regulations]
[Page 6975-7066]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr22ja01-29]
[[Page 6975]]
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Part VIII
Environmental Protection Agency
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40 CFR Parts 9, 141, and 142
National Primary Drinking Water Regulations; Arsenic and Clarifications
to Compliance and New Source Contaminants Monitoring; Final Rule
[[Page 6976]]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 9, 141 and 142
[WH-FRL-6934-9]
RIN 2040-AB75
National Primary Drinking Water Regulations; Arsenic and
Clarifications to Compliance and New Source Contaminants Monitoring
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: Today EPA is establishing a health-based, non-enforceable
Maximum Contaminant Level Goal (MCLG) for arsenic of zero and an
enforceable Maximum Contaminant Level (MCL) for arsenic of 0.01 mg/L
(10 µg/L). This regulation will apply to non-transient non-
community water systems, which are not presently subject to standards
on arsenic in drinking water, and to community water systems.
In addition, EPA is publishing clarifications for monitoring and
demonstration of compliance for new systems or sources of drinking
water. The Agency is also clarifying compliance for State-determined
monitoring after exceedances for inorganic, volatile organic, and
synthetic organic contaminants. Finally, EPA is recognizing the State-
specified time period and sampling frequency for new public water
systems and systems using a new source of water to demonstrate
compliance with drinking water regulations. The requirement for new
systems and new source monitoring will be effective for inorganic,
volatile organic, and synthetic organic contaminants.
DATES: This rule is effective March 23, 2001, except for the amendments
to Secs. 141.23(i)(1), 141.23(i)(2), 141.24(f)(15), 141.24(h)(11),
141.24(h)(20), 142.16(e), 142.16(j), and 142.16(k) which are effective
January 22, 2004.
The compliance date for requirements related to the clarification
for monitoring and compliance under Secs. 141.23(i)(1), 141.23(i)(2),
141.24(f)(15), 141.24(f)(22), 141.24(h)(11), 141.24(h)(20), 142.16(e),
142.16(j), and 142.16(k) is January 22, 2004. The compliance date for
requirements related to the revised arsenic standard under
Secs. 141.23(i)(4), 141.23(k)(3), 141.23(k)(3)(ii), 141.51(b),
141.62(b), 141.62(b)(16), 141.62(c), 141.62(d), and 142.62(b) is
January 23, 2006. For purposes of judicial review, this rule is
promulgated as of January 22, 2001.
ADDRESSES: Copies of the public comments received, EPA responses, and
all other supporting documents are available for review at the U.S. EPA
Water Docket (4101), East Tower B-57, 401 M Street, SW, Washington DC
20460. For an appointment to review the docket, call 202-260-3027
between 9 a.m. and 3:30 p.m. and refer to Docket W-99-16.
FOR FURTHER INFORMATION CONTACT: The Safe Drinking Water Hotline,
phone: (800) 426-4791, or (703) 285-1093, e-mail: hotline.sdwa@epa.gov
for general information about, and copies of, this document and the
proposed rule. For technical inquiries, contact: Jeff Kempic, (202)
260-9567, e-mail: kempic.jeffrey@epa.gov for treatment and costs, and
Dr. John B. Bennett, (202) 260-0446, e-mail: bennett.johnb@epa.gov for
benefits.
SUPPLEMENTARY INFORMATION:
Regulated Entities
A public water system (PWS), as defined in 40 CFR 141.2, provides
water to the public for human consumption through pipes or ``other
constructed conveyances, if such system has at least fifteen service
connections or regularly serves an average of at least twenty-five
individuals daily at least 60 days out of the year.'' A public water
system is either a community water system (CWS) or a non-community
water system (NCWS). A community water system, as defined in
Sec. 141.2, is ``a public water system which serves at least fifteen
service connections used by year-round residents or regularly serves at
least twenty-five year-round residents.'' The definition in Sec. 141.2
for a non-transient non-community water system (NTNCWS) is ``a public
water system that is not a [CWS] and that regularly serves at least 25
of the same persons over 6 months per year.'' EPA has an inventory
totaling over 54,000 community water systems and approximately 20,000
non-transient non-community water systems nationwide. Entities
potentially regulated by this action are community water systems and
non-transient non-community water systems. The following table provides
examples of the regulated entities under this rule.
Table of Regulated Entities
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Category Examples of regulated entities
------------------------------------------------------------------------
Industry.......................... Privately owned/operated community
water supply systems using ground
water, surface water, or mixed
ground water and surface water.
State, Tribal, and Local State, Tribal, or local government-
Government. owned/operated water supply systems
using ground water, surface water,
or mixed ground and surface water.
Federal Government................ Federally owned/operated community
water supply systems using ground
water, surface water, or mixed
ground water and surface water.
------------------------------------------------------------------------
The table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be regulated by this
action. This table lists the types of entities that EPA is now aware
could potentially be regulated by this action. Other types of entities
not listed in this table could also be regulated. To determine whether
your facility is regulated by this action, you should carefully examine
the applicability criteria in Secs. 141.11 and 141.62 of the rule. If
you have any questions regarding the applicability of this action to a
particular entity, consult the general information contact listed in
the section listing contacts for further information.
Abbreviations used in this rule
<--less than
<=--less than or equal to
>--greater than
>=--greater than or equal to
±--plus or minus
Sec. --section
s--s, Greek letter, in statistics represents standard
deviation
µg--Microgram, one-millionth of a gram (3.5 x
10-\8\ of an ounce)
µg/L--micrograms per liter
AA--Activated alumina
AIC--Akaike Information Criterion
ACWA--Association of California Water Agencies
AMWA--Association of Metropolitan Water Agencies
APHA--American Public Health Association
[[Page 6977]]
ARARs--Applicable or relevant and appropriate requirements
As (III)--Trivalent arsenic. Common inorganic form in water is arsenite
As (V)--Pentavalent arsenic. Common inorganic form in water is arsenate
ASDWA-- Association of State Drinking Water Administrators
AsH3--Arsine
ASTM--American Society for Testing and Materials
ATSDR--Agency for Toxic Substances and Disease Registry, U.S.
Department of Health & Human Services
AWWA--American Water Works Association
AWWARF--American Water Works Association Research Foundation
BAT--Best available technology
BV--Bed volume
CCR--Consumer Confidence Report
CERCLA--Comprehensive Environmental Response, Compensation, and
Liability Act administered by EPA for hazardous substances
C/F--Modified coagulation/filtration
CFR--Code of Federal Regulations
CSFII--Continuing Survey of Food Intakes by Individuals
CWA--Clean Water Act administered by EPA for surface waters of the U.S.
CWS--Community water system
CWSS--Community Water System Survey
DMA--Dimethyl arsinic acid, cacodylic acid,
(CH3)2HAsO2
DNA--Deoxyribonucleic acid
DWSRF--Drinking Water State Revolving Fund
EA--Economic analysis
EDR--Electrodialysis reversal
EEAC--Environmental Economics Advisory Committee
e.g.--exempli gratia, Latin for ``for example''
EPA--U.S. Environmental Protection Agency
et al.--et alia, Latin for ``and others''
FACA--Federal Advisory Committee Act
FR--Federal Register
FRFA--Final Regulatory Flexibility Analysis
FSIS--Federalism Summary Impact Statement
GDP--Gross Domestic Product
GFAA--Graphite furnace atomic absorption
GHAA--Gaseous hydride atomic absorption
GI--Gastrointestinal
GW--Ground water
GWR--Ground Water Rule
HRRCA--Health Risk Reduction and Cost Analysis
ICP-AES--Inductively coupled plasma-atomic emission spectroscopy
ICP-MS--Inductively coupled plasma mass spectroscopy
ICR--Information collection request
i.e.--id est, Latin for ``that is''
IOCs--Inorganic contaminants
ISCV--Intra-system coefficient of variation
IX--Ion exchange
L--Liter, also referred to as lower case ``l'' in older citations
LD50--The dose of a chemical taken by mouth or absorbed by
the skin which is expected to cause death in 50% of the test animals
LS--Modified lime softening
LT1/FBR--Long Term 1 Enhanced Surface Water Treatment and Filter
Backwash Recycling Rule
MCL--Maximum contaminant level
MCLG--Maximum contaminant level goal
MDL--Method detection limit
mg--Milligrams, one-thousandth of a gram, 1 milligram=1,000 micrograms
mg/kg--Milligrams arsenic per kilogram body weight or soil weight
mg/L--Milligrams per liter
MHI--Mean household income
MMA--Monomethyl arsenic, arsonic acid,
CH3H2ASO3
NAOS--National Arsenic Occurrence Survey
NAS--National Academy of Sciences
NAWQA--National Ambient Water Quality Assessment, USGS
NCI--National Cancer Institute
NCWS--Non-community water system
NDWAC--National Drinking Water Advisory Council for EPA
NIRS--National Inorganic and Radionuclide Survey done by EPA
NODA--Notice of Data Availability
NOMS--National Organic Monitoring Survey done by EPA
NPDES--National Pollutant Discharge Elimination System for CWA
NPDWR--National primary drinking water regulation
NR--Not reported
NRC--National Research Council, the operating arm of NAS
NTNCWS--Non-transient non-community water system
NTTAA--National Technology Transfer and Advancement Act
NWIS--National Water Information System of USGS
OGWDW--Office of Ground Water and Drinking Water in EPA
OMB--Office of Management and Budget
PE--Performance evaluation, studies to certify laboratories for EPA
drinking water testing
pH--Negative log of hydrogen ion concentration
PNR--Public Notification Rule
POE--Point-of-entry treatment devices
POTWs--Publicly owned treatment works, treat wastewater
POU--Point-of-use treatment devices
ppb--Parts per billion
ppm--Parts per million
PQL--Practical quantitation level
PRA--Paperwork Reduction Act
psi--Pounds per square inch
PT--Performance testing
PUC--Public utilities commission
PWS--Public water systems
QALYs--Quality adjusted life years
RCRA--Resource Conservation and Recovery Act
REF--Relative exposure factors
RFA--Regulatory Flexibility Act
RIA--Regulatory Impact Analysis
RO--Reverse osmosis
RUS--Rural Utilities Service
RWS--Rural Water Survey
SAB--Science Advisory Board
SBAR--Small Business Advocacy Review
SBREFA--Small Business Regulatory Enforcement Fairness Act
SD--Standard deviation
SDWA--Safe Drinking Water Act
SDWIS--Safe Drinking Water Information System
SEER--Surveillance, Epidemiology, and End Results
SM--Standard Method for Examination of Water and Wastewater
SMF--Standardized monitoring framework
SMRs--Standardized mortality ratios
SO4--Sulfate
SOCs--Synthetic organic contaminants
STP-GFAA--Stabilized temperature platform graphite furnace atomic
absorption
SW--Surface water
TBLLs--Technically based local limits
TC--Toxicity Characteristic, RCRA hazardous waste
TCLP--Toxicity Characteristic Leaching Procedure, tests for hazardous
waste
TDS--Total dissolved solids
TMF--Technical, managerial, financial capacity
TOC--Total organic carbon
UMRA--Unfunded Mandates Reform Act
URTH--Unreasonable risk to health
U.S.--United States
USDA--US Department of Agriculture
USGS--US Geological Survey
UV--Ultraviolet
VOCs--Volatile organic contaminants
VSL--Value of statistical life
VSLY--Value of statistical life year
WHO--World Health Organization
WS--Water supply
WTP--Willingness-to-pay
Table of Contents
I. Background and Summary of the Final Rule
A. What Did EPA Propose?
B. Overview of the Notice of Data Availability (NODA)
C. Does This Regulation Apply to My Water System?
[[Page 6978]]
D. What are the Final Drinking Water Regulatory Standards for
Arsenic (Maximum Contaminant Level Goals and Maximum Contaminant
Levels)?
E. Will There be a Health Advisory?
F. What are the Best Available Technologies For Removing Arsenic
From Drinking Water?
1. BAT technologies
2. Preoxidation
3. Factors affecting listing technologies
4. Other technologies evaluated, but not designated as BAT
5. Waste disposal
G. Treatment Trains Considered For Small Systems
1. Can my water system use point-of-use (POU), point-of-entry
(POE), or bottled water to comply with this regulation?
2. What are the affordable treatment technologies for small
systems?
3. Can my water system get a small system variance from an MCL
under today's rule?
H. Can My System Get a General Variance or Exemption from the MCL
Under Today's Rule?
I. What Analytical Methods are Approved for Compliance Monitoring of
Arsenic and What are the Performance Testing Criteria for Laboratory
Certification?
1. Approved analytical methods
2. Performance testing criteria for laboratory certification
J. How Will I Know if My System Meets the Arsenic Standard?
1. Sampling points and grandfathering of monitoring data
2. Compositing of samples
3. Calculation of violations
4. Monitoring and compliance schedule
K. What do I Need To Tell My Customers?
1. Consumer Confidence Reports
a. General requirements
b. Special informational statement
2. Public Notification
L. What Financial Assistance Is Available for Complying With This
Rule?
M. What is the Effective Date and Compliance Date for the Rule?
N. How Were Stakeholders Involved in the Development of This Rule?
II. Statutory Authority
III. Rationales for Regulatory Decisions
A. What is the MCLG?
B. What is the Feasible Level?
1. Analytical measurement feasibility
2. Treatment
C. How Did EPA Revise Its National Occurrence Estimates?
1. Summary of occurrence data and methodology
2. Corrections and additions to the data
3. Changes to the methodology
4. Revised occurrence results
D. How Did EPA Revise Its Risk Analysis?
1. Health risk analysis
a. Toxic forms of arsenic
b. Effects of acute toxicity
c. Non-cancer effects associated with arsenic.
d. Cancers associated with arsenic
e. How does arsenic cause cancer?
f. What is the quantitative relationship between exposure and
cancer effects that may be projected for exposures in the U.S.?
g. Is it appropriate to assume linearity for the dose-response
assessment for arsenic at low doses given that arsenic is not
directly reactive with DNA?
2. Risk factors/bases for upper- and lower-bound analyses
a. Water consumption
b. Relative Exposure Factors
c. Arsenic occurrence
d. Risk distributions
e. Estimated risk reductions
f. Lower-bound analyses
g. Cases avoided
3. Sensitive subpopulations
4. Risk window
E. What are the Costs and Benefits at 3, 5, 10, and 20 µg/L?
1. Summary of cost analysis
a. Total national costs
b. Household costs
2. Summary of benefits analysis
a. Primary analysis
b. Sensitivity analysis on benefits valuation
c. SAB recommendations
d. Analytical approach
e. Results
3. Comparison of costs and benefits
a. Total national costs and benefits
b. National net benefits and benefit-cost ratios
c. Incremental costs and benefits
d. Cost-per-case avoided
4. Affordability
F. What MCL Is EPA Promulgating and What Is the Rationale for This
Level?
1. Final MCL and overview of principal considerations
2. Consideration of health risks
3. Comparison of benefits and costs
4. Rationale for the final MCL
a. General considerations
b. Relationship of MCL to the feasible level (3 µg/L)
c. Reanalysis of proposed MCL and comparison to final MCL
d. Consideration of higher MCL options
e. Conclusion
IV. Rule Implementation
A. What are the Requirements for Primacy?
B. What are the Special Primacy Requirements?
C. What are the State Recordkeeping Requirements?
D. What are the State Reporting Requirements?
E. When does a State Have to Apply for Primacy?
F. What are Tribes Required To Do Under This Regulation?
V. Responses to Major Comments Received
A. General Comments
1. Sufficiency of information and adequacy of procedural
requirements to support a final rule
2. Suggestions for development of an interim standard
3. Public involvement and opportunity for comment
4. Relation of MCL to the feasible level
5. Relationship of MCL to other regulatory programs
6. Relation of MCL to WHO standard
7. Regulation of non-transient non-community water systems
(NTNCWSs)
8. Extension of effective date for large systems
B. Health Effects of Arsenic
1. Epidemiology data
2. Dose-response relationship
3. Suggestions that EPA await further health effects research
4. Sensitive subpopulations
5. EPA's risk analysis
6. Setting the MCLG and the MCL
C. Occurrence
1. Occurrence data
2. Occurrence methodology
3. Co-occurrence
D. Analytical Methods
1. Analytical interferences
2. Demonstration of PQL (includes acceptance limits)
3. Acidification of samples
E. Monitoring and Reporting Requirements
1. Compliance determinations
2. Monitoring of POU devices
3. Monitoring and reporting for NTNCWSs
4. CCR health language and reporting date
5. Implementation guidance
6. Rounding analytical results
F. Treatment Technologies
1. Demonstration of technology performance
2. Barriers to technology application
3. Small system technology application
4. Waste generation and disposal
a. Anion exchange
b. Activated alumina
c. Reverse osmosis
5. Emerging technologies
G. Costs
1. Disparity of costs
a. What is EPA's response to major comments on the decision tree
for the proposed rule?
b. What is EPA's response to comments on system level costs?
c. What is EPA's response to comments that state the report
``Cost Implications of a Lower Arsenic MCL'' (Frey et al., 2000), be
used as a basis for reflecting more realistic national costs than
EPA's estimates?
2. Affordability
3. Combined cost of new regulations
4. Projected effects of the new standard on other regulatory
programs.
H. Benefits of Arsenic Reduction
1. Timing of benefits accrual (latency)
2. Use of the Value of Statistical Life (VSL)
3. Use of alternative methodologies for benefits estimation
4. Comments on EPA's consideration of nonquantifiable benefits
5. Comments on EPA's assumption of benefits accrual prior to
rule implementation
I. Risk Management Decision
1. Role of uncertainty in decision making
2. Agency's interpretation of benefits justify costs provision
3. Alternative regulatory approaches
4. Standard for total arsenic vs. species-specific standards
J. Health Risk Reduction and Cost Analysis (HRRCA)
1. Notice and comment requirement
2. Conformance with SDWA requirements
[[Page 6979]]
VI. Administrative and Other Requirements
A. Executive Order 12866: Regulatory Planning and Review
B. Regulatory Flexibility Act (RFA), as Amended by the Small
Business Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5
U.S.C. 601 et seq.
C. Unfunded Mandates Reform Act (UMRA) of 1995
a. Authorizing legislation
b. Cost-benefit analysis
c. Financial assistance
d. Estimates of future compliance costs and disproportionate
budgetary effects
e. Macroeconomic effects
f. Summary of EPA's consultation with State, Tribal, and local
governments
g. Nature of State, Tribal, and local government concerns and how
EPA addressed these concerns
h. Regulatory alternatives considered
i. Selection of the regulatory alternative
D. Paperwork Reduction Act (PRA)
E. National Technology Transfer and Advancement Act (NTTAA)
F. Executive Order 12898: Environmental Justice
G. Executive Order 13045: Protection of Children from Environmental
Health Risks and Safety Risks
H. Executive Order 13132: Federalism
I. Executive Orders 13084 and 13175: Consultation and Coordination with
Indian Tribal Governments
J. Plain Language
K. Congressional Review Act
L. Consultations with the Science Advisory Board, National Drinking
Water Advisory Council, and the Secretary of Health and Human Services
M. Likely Effect of Compliance With the Arsenic Rule on the Technical,
Financial, and Managerial Capacity of Public Water Systems
VI. References
List of Tables
Table I.F-1.--Best Available Technologies and Removal Rates
Table I.G-1.--Treatment Technology Trains
Table I.G-2.--Baseline Values for Small Systems Categories
Table I.G-3.--Available Expenditure Margin for Affordable Technology
Determinations
Table I.G-4.--Design and Average Daily Flows Used for Affordable
Technology Determinations
Table I.G-5.--Affordable Compliance Technology Trains for Small
Systems with population 25-500
Table I.G-6.--Affordable Compliance Technology Trains for Small
Systems with populations 501-3,300 and 3,301 to 10,000
Table I.I-1.--Approved Analytical Methods (40 CFR 141.23) for
Arsenic at the MCL of 0.01 mg/L
Table III.C-1.--Summary of Occurrence Databases for the Proposed and
Final Rules
Table III.C-2.--Alaska PWS Inventories: Baseline Handbook and
Corrected
Table III.C-3.--National Occurrence Exceedance Probability Estimates
Table III.C-4.--Parameters of Lognormal Distributions Fitted to
National Occurrence Distributions
Table III.C-5.--Regional Occurrence Exceedance Probability Estimates
Table III.C-6.--Statistical Estimates of Numbers of Systems with
Average Finished Arsenic Concentrations in Various Ranges
Table III.C-7.--Estimated Intra-System Coefficients of Variation
Table III.C-8.--Comparison of National Arsenic Occurrence Estimates
Table III.D-1.--Life-Long Relative Exposure Factors
Table III.D-2(a).--Cancer Risks for U.S. Populations Exposed At or
Above MCL Options, after Treatment1,2 (Without Adjustment
for Arsenic in Food and Cooking Water)
Table III.D-2(b).--Cancer Risks for U.S. Populations Exposed At or
Above MCL Options, after Treatment1,2 (With Adjustment
for Arsenic Exposure in Food and Cooking Water)
Table III.D-2(c).--Cancer Risks for U.S. Populations Exposed At or
Above MCL Options, after Treatment1 (Lower Bound With
Food and Cooking Water Adjustment, Upper Bound Without Food and
Cooking Water Adjustment)
Table III.D-3.--Annual Total (Bladder and Lung) Cancer Cases Avoided
from Reducing Arsenic in CWSs and NTNCWS
Table III.E-1.--Total Annual National System and State Compliance
Costs
Table III.E-2.--Mean Annual Costs per Household
Table III.E-3.--Estimated Benefits from Reducing Arsenic in Drinking
Water
Table III.E-4.--Sensitivity of the Primary VSL Estimate to Changes
in Latency Period Assumptions, Income Growth, and Other Adjustments
Table III.E-5.--Sensitivity of Combined Annual Bladder and Lung
Cancer Mortality Benefits Estimates to Changes in VSL Adjustment
Factor Assumptions
Table III.E-6.--Sensitivity of Combined Annual Bladder and Lung
Cancer Mortality Benefits Estimates to Changes in VSL Adjustment
Factor Assumptions
Table III.E-7.--Estimated Annual Costs and Benefits from Reducing
Arsenic in Drinking Water
Table III.E-8 Summary of National Annual Net Benefits and Benefit-
Cost Ratios, Combined Bladder and Lung Cancer Cases
Table III.E-9 Estimates of the Annual Incremental Risk Reduction,
Costs, and Benefits of Reducing Arsenic in Drinking Water
Table III.E-10. Annual Cost Per Cancer Case Avoided for the Final
Arsenic Rule--Combined Bladder and Lung Cancer Cases
TABLE V.F-4.1 Treatment Trains in Final Versus Proposed Arsenic Rule
Decision Tree
Table V.F-4.2 New or Revised Treatment Trains
Table VI.B-1. Profile of the Universe of Small Water Systems
Regulated Under the Arsenic Rule
I. Background and Summary of the Final Rule
A. What Did EPA Propose?
On June 22, 2000, the Federal Register published EPA's proposed
arsenic regulation for community water systems and non-transient non-
community water systems (65 FR 38888; EPA, 2000i). EPA proposed a
health-based, non-enforceable goal, or Maximum Contaminant Level Goal
(MCLG), of zero micrograms per liter (µg/L) and a Maximum
Contaminant Level (MCL) of 5 µg/L. The Agency also requested
comment on alternate MCL levels of 3 µg/L, 10 µg/L, and
20 µg/L. (In the proposed rule EPA expressed arsenic
concentration in milligrams per liter (mg/L) or parts per million,
which matches the units of the former and current standard for arsenic.
Except as noted, the Agency will refer to arsenic concentration in
micrograms per liter (µg/L) in this preamble.)
EPA based the June 2000 proposal on extensive analysis including a
careful consideration of the following issues: a nonzero MCLG;
occurrence of arsenic in public water systems; our approach for
estimating national occurrence and co-occurrence; acceptance limits
used to establish the practical quantitation level (PQL); rounding of
measured values for compliance purposes; extending compliance by two
years for systems serving under 10,000 people in order to add capital
improvements; dates for reporting changes in the consumer confidence
reports and public notification; appropriateness of the national
affordability criteria; affordable technologies for small systems;
implementation issues for point-of-use (POU) and point-of-entry (POE)
treatments; appropriateness of non-hazardous residual costing; our
overall analysis of costs; adjusting benefits estimates (e.g., for
factors such as latency); our approach for considering uncertainties
that affected risk; use of the authority to set an MCL at a level other
than the feasible MCL; expression of the MCL as total arsenic;
approaches to regulation of NTNCWSs; State program revisions; selenium
levels as an attenuation factor in arsenic toxicity; impacts on small
entities; use of consensus analytical methods; methods to address
environmental justice concerns; and comments on use of plain
[[Page 6980]]
language. We asked commenters to submit data and comments on these
issues, as well as any other issues raised in the proposal.
The proposal reflected several types of technical evaluations,
including analytical methods performance and laboratory capacity; the
likelihood of different size water systems choosing treatment
technologies based on source water characteristics; and the national
occurrence of arsenic in drinking water supplies. Furthermore, the
Agency assessed the quantifiable and nonquantifiable costs and health
risk reduction benefits likely to occur at the treatment levels
considered, and the effects of arsenic on sensitive subpopulations.
The proposed MCL was consistent with the Agency's use of the new
benefit/cost provisions of the Safe Drinking Water Act (SDWA), as
amended in 1996 (see section II. of this preamble for additional
information about this provision). EPA proposed 3 µg/L as the
feasible MCL, after considering treatment costs and efficiency under
field conditions as well as considering the appropriate analytical
methods. Because EPA determined that the benefits of regulating arsenic
at the feasible level would not justify the costs, the Agency proposed
an MCL of 5 µg/L, while requesting comment on MCL options of 3
µg/L (the feasible level), 10 µg/L, and 20 µg/
L.
We based our estimates of large system compliance costs primarily
on costs for coagulation/filtration and lime softening, although we
consider several other technologies to be appropriate as best available
technology (BAT) technologies. (See Table I.F-1.) For small-system
(systems serving 10,000 people and less) compliance costs, we
considered the costs for ion exchange, activated alumina, reverse
osmosis, and nanofiltration. EPA proposed extending the effective date
to five years after the final rule issuance for small community water
systems and maintaining the effective date at three years after
promulgation for all other community water systems. EPA proposed that
States applying to adopt the revised arsenic MCL may use their most
recently approved monitoring and waiver plans or note in their primacy
application any revisions to those plans. EPA proposed that NTNCWSs
monitor for arsenic and report exceedances of the MCL.
The Agency also clarified the procedure used for determining
compliance after exceedances for inorganic, volatile organic, and
synthetic organic contaminants in Secs. 141.23(i)(2),
141.24(f)(15)(ii), and 141.24(h)(11)(ii), respectively. Finally, EPA
proposed that new systems and systems using a new source of water be
required to demonstrate compliance with the MCLs using State-specified
time frames. The clarified new source and new system compliance
regulations require that States establish initial sampling frequencies
and compliance periods for inorganic, volatile organic, and synthetic
organic contaminants in Secs. 141.23(c)(9), 141.24(f)(22), and
141.24(h)(20), respectively.
B. Overview of the Notice of Data Availability (NODA)
In the proposed rule, EPA quantified the risk reduction and
benefits of avoiding bladder cancer and noted that a peer-reviewed
quantification of lung cancer risk from arsenic exposure would probably
be available in time to consider for the final rule (65 FR 38888 at
38899; EPA, 2000i). Relying upon a discussion in the National Research
Council (NRC) report (NRC, 1999, pg. 8) about the qualitative risks of
lung cancer (65 FR 38888 at 38944; 2000i), EPA provided a ``What-If''
estimate of lung cancer benefits (65 FR 38888 at 38946, 2000i) in the
proposed rule. On October 20, 2000, the Federal Register published
EPA's Notice of Data Availability (NODA) containing a revised risk
analysis for bladder cancer and new risk information concerning lung
cancer (65 FR 63027; EPA, 2000m), and identified a correction to Table
4 on October 27, 2000 (65 FR 64479; EPA, 2000n). The NODA also provided
information concerning the availability of cost curves used to develop
the costs published in the proposal.
EPA used new risk information for lung and bladder cancer from a
peer-reviewed article written by Morales et al. (2000). In the NODA,
EPA explained that the authors used several alternative statistical
models to estimate cancer risk. EPA explained its reasons for selecting
``Model 1'' with no comparison population for further analysis. We used
daily water consumption (EPA, 2000c) reported by gender, region, age,
economic status, race, and separately for pregnant women, lactating
women, and women in childbearing years combined with weight data to
derive exposure factors for the U.S. We used these exposure factors,
our occurrence estimate (EPA 2000g) of populations exposed to arsenic
at different concentrations, and the risk distributions from the
Morales et al. (2000) paper in Monte Carlo simulations to estimate the
upper bound of risks faced by the U.S. population. The NODA compared
the bladder cancer risks derived for the proposal against the bladder
cancer risks derived from the Morales et al. (2000) study. EPA also
derived lung cancer risks using the same approach and the risk model
contained in the Morales et al. (2000) study.
EPA also used the newly calculated risks to estimate a lower bound
risk in the U.S. This calculation took into account the amount of
additional arsenic people in Taiwan were likely to have ingested from
water used in food preparation. EPA showed the effects on risks for the
U.S. population at both the mean and 90th percentile levels for various
arsenic levels in drinking water. Based on the revised risk assessment,
we updated our assessment of the relative risk of lung cancer as
compared to bladder cancer. The NODA indicated that instead of being 2
to 5 times as many fatal lung cancer cases as bladder cancer cases (as
was cited in NRC's Executive Summary, NRC, 1999, pg. 8 as a qualitative
estimate), the combined risk of excess lung and bladder cancer were
thought to be only about twice that of bladder cancer risk. EPA noted
that, while the new risks were higher than the bladder cancer risk in
the proposal, the monetized benefits of lung cancer would fall within
the lung cancer benefits range estimated using the ``What-If'' analysis
(e.g., $19.6 million--$224 million yearly for an MCL of 10 µg/
L) in the proposal (65 FR 38888 at 38959; EPA, 2000m).
In the NODA, EPA also explained that the docket for the proposed
rule had the November 1999 version (EPA, 1999o) of ``Technologies and
Costs for the Removal of Arsenic from Drinking Water'' rather than the
April 1999 version of the document that was the primary source for the
treatment technology cost equations used to generate the national cost
estimate. The national cost estimate was presented in the ``Proposed
Arsenic in Drinking Water Rule Regulatory Impact Analysis'' (EPA,
2000h). The NODA therefore announced the availability of the
``Technologies and Costs for the Removal of Arsenic from Drinking
Water,'' dated April 1999 (EPA,1999b). The NODA also noted that
commenters interested in reproducing the waste disposal curves should
consult the ``Small Water System Byproducts Treatment and Disposal Cost
Document'' (EPA, 1993a) and ``Water System Byproducts Treatment and
Disposal Document (EPA, 1993b).'' In addition to placing these
documents in the docket, the NODA also specified that an electronic
copy of the treatment technology and waste disposal equations used in
the development of the RIA could be found in the docket.
[[Page 6981]]
EPA made the April 1999 version of the document, ``Technologies and
Costs for the Removal of Arsenic from Drinking Water'' (EPA,1999b)
available on its arsenic webpage.
The cost methodology and cost estimates were clearly stated and
explained in the proposal for public review and consideration. Through
a technical oversight, we incorrectly attributed the source for the
cost curves to the November version of the document placed in the
docket (EPA, 1999o). As a result, people could not replicate the
precise analysis we did, should a commenter desire to do so. More
specifically, although the inputs, assumptions, and model methodology
were clearly explained, we incorrectly cited the sources of an
intermediate step of deriving specific cost curves from those
assumptions. Based upon the proposal's detailed discussion of inputs,
assumptions and associated methodology, EPA believes the public was
fully able to review, understand, and comment on the Agency's estimate
of potential impacts. EPA discusses the cost curves further in section
III.E.1 of this preamble.
C. Does This Regulation Apply to My Water System?
The final regulation on arsenic in drinking water promulgated today
applies to all CWSs and NTNCWSs. The regulation not only establishes an
MCLG and MCL for arsenic, but also lists feasible technologies and
affordable technologies for small systems that can be used to comply
with the MCL. However, systems are not required to use the listed
technologies in order to meet the MCL.
D. What are the Final Drinking Water Regulatory Standards for Arsenic
(Maximum Contaminant Level Goals and Maximum Contaminant Levels)?
In today's rule, the MCLG is 0 µg/L, and the enforceable
MCL is 0.01 mg/L, which is the same as 10 micrograms per liter
(µg/L) or 10 parts per billion (ppb). EPA based the MCL on
total arsenic, because drinking water contains almost entirely
inorganic forms, and the analytical methods for total arsenic are
readily available and capable of being performed by certified
laboratories at an affordable cost.
E. Will There be a Health Advisory?
A health advisory for arsenic is not part of today's rulemaking.
EPA will be considering whether or not to issue a health advisory after
evaluating the recommendations of the Science Advisory Board (SAB)
(EPA, 2000q). The purpose of an advisory would be to provide useful
information to water providers between issuance and implementation of
this rule.
F. What are the Best Available Technologies For Removing Arsenic From
Drinking Water?
Section 1412(b)(4)(E) of the Safe Drinking Water Act states that
each National Primary Drinking Water Regulation (NPDWR) which
establishes an MCL shall list the technology, treatment techniques, and
other means that the Administrator finds to be feasible for purposes of
meeting the MCL. Technologies are judged to be a best available
technology (BAT) when the following criteria are satisfactorily met:
(1) The capability of a high removal efficiency;
(2) A history of full-scale operation;
(3) General geographic applicability;
(4) Reasonable cost based on large and metropolitan water systems;
(5) Reasonable service life;
(6) Compatibility with other water treatment processes; and
(7) The ability to bring all of the water in a system into
compliance.
EPA identified BATs in this section using the listed criteria.
Their removal efficiencies and a brief discussion of the major issues
surrounding the usage of each technology are also given in this
section. More details about the treatment technologies and costs can be
found in ``Technologies and Costs for the Removal of Arsenic From
Drinking Water'' (EPA, 2000t).
1. BAT technologies
EPA reviewed several technologies as BAT candidates for arsenic
removal, e.g., ion exchange, activated alumina, reverse osmosis,
nanofiltration, electrodialysis reversal, coagulation assisted
microfiltration, modified coagulation/filtration, modified lime
softening, greensand filtration, conventional iron and manganese
removal, and several emerging technologies. The Agency determined that,
of the technologies capable of removing arsenic from source water, only
the technologies in Table I.F-1 fulfill the requirements of SDWA for
BAT determinations for arsenic. The maximum percent of arsenic removal
that can be reasonably obtained from these technologies is also shown
in the table. These removal efficiencies are for arsenic (V) removal.
Table I.F-1.-- Best Available Technologies and Removal Rates
------------------------------------------------------------------------
Maximum
Treatment Technology Percent
Removal \1\
------------------------------------------------------------------------
Ion Exchange (sulfate <= 50 mg/L)................. 95
Activated Alumina.......................................... 95
Reverse Osmosis............................................ >95
Modified Coagulation/Filtration............................ 95
Modified Lime Softening (pH > 10.5)........................ 90
Electrodialysis Reversal................................... 85
Oxidation/Filtration (20:1 iron:arsenic)................... 80
------------------------------------------------------------------------
\1\ The percent removal figures are for arsenic (V) removal. Pre-
oxidation may be required.
2. Preoxidation
In water, the most common valence states of arsenic are As (V), or
arsenate, and As (III), or arsenite. As (V) is more prevalent in
aerobic surface waters and As (III) is more likely to occur in
anaerobic ground waters. In the pH range of 4 to 10, As (V) species
(H2AsO4\-\ and
H2AsO42\-\) are negatively charged,
and the predominant As (III) compound (H3AsO3) is
neutral in charge. Removal efficiencies for As (V) are much better than
removal of As (III) by any of the technologies evaluated because the
arsenate species carry a negative charge and arsenite is neutral under
these pH conditions. To increase the removal efficiency when As (III)
is present, pre-oxidation to the As (V) species is necessary.
As (III) may be converted through pre-oxidation to As (V) using one
of several oxidants. Data on oxidants indicate that chlorine, potassium
permanganate, and ozone are effective in oxidizing As (III) to As (V).
Pre-oxidation with chlorine may create undesirable concentrations of
disinfection byproducts and membrane fouling of subsequent treatments
such as reverse osmosis. EPA has completed research on the chemical
oxidants for As (III) conversion, and is presently investigating
ultraviolet light disinfection technology (UV) and solid oxidizing
media. For POU and POE devices, central chlorination may be required
for oxidation of As (III).
3. Factors affecting listing technologies
Ion Exchange (IX) can effectively remove arsenic using anion
exchange resins. It is recommended as a BAT primarily for sites with
low sulfate because sulfate is preferred over arsenic. Sulfate will
compete for binding sites resulting in shorter run lengths. Due to much
shorter run lengths than activated alumina, anion exchange must be
[[Page 6982]]
regenerated because it is not cost effective to dispose of the resin
after one use. Column bed regeneration frequency is a key factor in the
cost of the process and affects the volume of waste produced by the
process. The proposed rule preamble noted that anion exchange may be
practical up to approximately 120 mg/L of sulfate (Clifford, 1994). The
upper-bound sulfate concentration for the final rule is 50 mg/L. The
selection of this upper bound is based on several factors, including
cost and the ability to dispose of the brine stream.
The proposed rule listed three mechanisms to dispose of the brine
stream used for regeneration. The options were: sanitary sewer,
evaporation pond, and chemical precipitation. Many comments on the
proposed rule were based on the assumption that the waste streams
generated would be considered hazardous waste. Waste streams containing
less than 0.5% solids are evaluated against the toxicity characteristic
directly to determine if the waste is hazardous. Arsenic in the
regeneration brine will likely exceed 5 mg/L for most systems with
arsenic above 10 µg/L and sulfate below 50 mg/L. Since the
brine stream would likely be considered hazardous, EPA eliminated the
evaporation pond and the chemical precipitation options from the
decision tree as options for disposal of anion exchange wastes. The
Agency retained discharge to a sanitary sewer because domestic sewage
and any mixture of domestic sewage and other wastes that pass through a
sewer system to a publicly owned treatment works (POTW) for treatment
is excluded from consideration as solid waste (40 CFR 261.4). Domestic
sewage means untreated sanitary wastes that pass through a sewage
system. Discharges meeting the previously stated criteria are excluded
from regulation as hazardous waste. However, these assumptions were
reviewed to substantially reduce projections of brine wastes going to
POTWs from those that were used in support of the proposed rule.
Discharge to a sanitary sewer can be limited by technically based
local limits (TBLLs) for arsenic or total dissolved solids. Since anion
exchange is regenerated more frequently than activated alumina, the
total dissolved solids increase can be significant. Many comments
indicated that significant increases in total dissolved solids would be
unacceptable, especially in the Southwest where water resources are
scarce. Salt is used for regeneration of anion exchange resins. The
upper bound of 50 mg/L sulfate for anion exchange is based on projected
increases of total dissolved solids using the quantity of salt needed
for regeneration and the frequency of regeneration (based on sulfate).
The sulfate upper bound for the final rule is significantly lower than
the upper bound from the proposed rule. Due to the potential for an
increase in total dissolved solids, anion exchange would be favored in
areas other than the Southwest where the volume of brine is very small
relative to the total volume of wastewater being treated at the POTW.
Systems that need to treat only a few entry points or can blend a
significant portion of the water to meet the MCL may produce a smaller
brine stream to allow the brine to be discharged to a POTW. Water
systems should check with the POTW to ensure that the brine stream will
be accepted before selecting this option.
Activated Alumina (AA) is an effective arsenic removal technology;
however, the capacity of activated alumina to remove arsenic is very pH
sensitive. High removals can be achieved over a broad range of pH, but
shorter run lengths will be observed at higher pH. Activated alumina
can be operated in one of two ways. The activated alumina can either be
disposed of or regenerated after the media is exhausted. Under the
regeneration option, strong acids and bases are used to remove arsenic
from the media so that it can be used again to remove arsenic. Because
arsenic is strongly adsorbed to the media, only about 50-70% of the
adsorbed arsenic is removed. The brine stream produced by the
regeneration process then requires disposal. The proposed rule listed
discharge to a sanitary sewer as the disposal mechanism for the brines.
Many comments on the proposed rule noted that TBLLs for arsenic or
total dissolved solids might restrict discharge of brine streams to the
sanitary sewer. Since activated alumina run lengths (i.e., number of
bed volumes (BV) per run) are much longer than anion exchange, the
arsenic concentrations in the brine stream would likely be much higher.
Regeneration of activated alumina media is not recommended for larger
systems because: (1) Disposal of the brine may be difficult, (2) the
regeneration process is incomplete which reduces subsequent run
lengths, and (3) for most systems it will be cheaper to replace the
media rather than regenerate it. The option of replacing the spent
media with new media is called disposable activated alumina.
The disposable activated alumina option can be operated both at the
optimal pH of 6 and at higher natural water pH values. It is expected
that larger systems would adjust pH to take advantage of the longer run
lengths. EPA developed several disposable activated alumina options for
the final rule. Two options were based on operating the process at the
natural pH of the water (no pH adjustment). These options are intended
primarily for smaller systems, although larger systems may also be able
to operate at the natural pH if it is low enough to get sufficiently
long run lengths. Two options where the pH was adjusted to pH 6 were
also examined. The longer run length is based on using sulfuric acid to
lower the pH. However, sulfate can compete for adsorption sites with
arsenic. It was recommended that hydrochloric acid be used to obtain a
longer run length (Clifford et al., 1998). When pH is adjusted to pH 6,
post-treatment corrosion control will be necessary.
In our analysis, we assumed that spent media could be safely
disposed of in a non-hazardous landfill. The preamble to the proposed
rule described results from testing of activated alumina media used to
remove arsenic in drinking water systems with arsenic above 50
µg/L. The results from the Toxicity Characteristic Leaching
Procedure (TCLP) on these samples was typically less that 50
µg/L. The current toxicity characteristic (TC) regulatory level
for designating arsenic as a hazardous waste under the Resource
Conservation and Recovery Act (RCRA) is 5 mg/L (5000 µg/L) and
is listed in 40 CFR 261.24(a). The TC regulatory level is one hundred
times higher than the results from the activated alumina samples.
Reverse Osmosis (RO) can provide removal efficiencies of greater
than 95% when operating pressure is ideal. Water rejection (on the
order of 20-25%) may be an issue in water-scarce regions and may prompt
systems employing RO to seek greater levels of water recovery. Water
recovery is the volume of drinking water produced by the process
divided by the influent stream (product water/influent stream).
Increased water recovery is often more expensive, since it can involve
recycling of water through treatment units to allow more efficient
separation of solids from water. This can also produce more
concentrated solid wastes. However, the waste stream will generally not
be as concentrated as anion exchange brines, so it should be easier to
dispose of. Based on the cost of the process, it is unlikely that
reverse osmosis would be installed solely for arsenic removal. Blending
a treated portion with an untreated portion and
[[Page 6983]]
still meeting the MCL would make reverse osmosis more cost effective.
If blending is not an option, post-treatment corrosion control would be
necessary. Since a large portion of the water is wasted, water quantity
could be an issue, especially in the Western U.S. It should be noted
that while reverse osmosis is listed as a BAT, it was not used to
develop national costs because other options are more cost effective
and have much smaller waste streams.
Modified Coagulation/Filtration (C/F) is an effective treatment
process for removal of As (V) according to laboratory, pilot-plant, and
full-scale tests. The type of coagulant and dosage used affects the
efficiency of the process. Below a pH of approximately 7, removals with
alum or ferric sulfate/chloride are similar. Above a pH of 7, removals
with alum decrease dramatically (at a pH of 7.8, alum removal
efficiency is about 40%). Other coagulants are also less effective than
ferric sulfate/chloride. Systems may need to lower pH or add more
coagulant to achieve higher removals.
Modified Lime Softening (LS), operated within the optimum pH range
of greater than 10.5 is likely to provide a high percentage of As
removal. Systems operating lime softening at lower pH will need to
increase the pH to achieve higher removals of arsenic.
Coagulation/Filtration and Lime Softening are unlikely to be
installed solely for arsenic removal. Systems considering installation
of one of these technologies should design the process to operate in
the optimal pH range if high removal efficiencies are needed for
compliance.
Electrodialysis Reversal (EDR) can produce effluent water quality
comparable to reverse osmosis. EDR systems are fully automated, require
little operator attention, and do not require chemical addition. EDR
systems, however, are typically more expensive than nanofiltration and
reverse osmosis systems. These systems are often used in treating
brackish water to make it suitable for drinking. This technology has
also been applied in the industry for wastewater recovery and typically
operates at a recovery of 70 to 80%. Since a large portion of the water
is wasted, water quantity could be an issue, especially in the Western
U.S. It should be noted that while electrodialysis reversal is listed
as a BAT, it was not used to develop national costs because other
options are more cost effective and have much smaller waste streams.
Oxidation/Filtration (including greensand filtration) has an
advantage in that there is not as much competition with other ions.
Arsenic is co-precipitated with the iron during iron removal.
Sufficient iron needs to be present to achieve high arsenic removals.
One study recommended a 20:1 iron to arsenic ratio (Subramanian et al.,
1997). Removals of approximately 80% were achieved when iron to arsenic
ratio was 20:1. When the iron to arsenic ratio was lower (7:1),
removals decreased below 50%. The presence of iron in the source water
is critical for arsenic removal. If the source water does not contain
iron, oxidizing and filtering the water will not remove arsenic. When
the arsenic is present as As(III), sufficient contact time needs to be
provided to convert the As(III) to As(V) for removal by the oxidation/
filtration process. An additional pre-oxidation step is not required
for this process as long as there is sufficient contact time. In
developing national cost estimates, EPA assumed that systems would opt
for this type of technology only if more than 300 µg/L of iron
was present. The Agency assumed a removal percentage of 50% when
estimating national costs because the 20:1 ratio could not be verified
due to limitations in the co-occurrence database. However, EPA assumed
a removal percentage of 80% as part of a sensitivity analysis. At
proposal EPA indicated that oxidation filtration was not being listed
as BAT because it has a low removal efficiency, which might not be
appropriate for an MCL of 5. However, the Agency also noted that this
technology may be appropriate for systems that do not require high
arsenic removal and had high iron in their source water. Because this
is an inexpensive technology that is particularly effective for high-
iron, low-arsenic waters, EPA is listing oxidation/filtration as a BAT
with a footnote that the iron-to-arsenic ratio must be at least 20:1.
Systems with greater than 300 µg/L of iron will also see
benefits in the aesthetic quality of the water as the iron can be
reduced below the secondary standard. EPA's inclusion of oxidation/
filtration as a BAT in today's final rule is based upon further
evaluation of all available information and studies as well as on
public comments.
4. Other technologies evaluated, but not designated as BAT
Coagulation Assisted Microfiltration. The coagulation process
described previously can be linked with microfiltration to remove
arsenic. The microfiltration step essentially takes the place of a
conventional gravity filter. The University of Houston recently
completed pilot studies at Albuquerque, New Mexico on iron coagulation
followed by a direct microfiltration system. The results of this study
indicated that iron coagulation followed by microfiltration is capable
of removing arsenic (V) from water to yield concentrations that are
consistently below 2 µg/L. Critical operating parameters are
iron dose, mixing energy, detention time, and pH (Clifford, 1997).
Coagulation and microfiltration as separate processes have both been
installed full scale, but the combined coagulation/microfiltration
process does not have a full-scale operation history. Since a full-
scale operation history is one of the requirements to list a technology
as a BAT, it is not presently being listed as one. It could be
designated as such in the future if the technology meets that
requirement. EPA used this option in developing the national cost
estimate because we believe coagulation/microfiltration is an
appropriate technology that will be used by certain water systems to
comply with this rule, even though it is not currently listed as BAT
for the reasons mentioned.
Granular ferric hydroxide is a technology that may combine very
long run length without the need to adjust pH. The technology has been
demonstrated for arsenic removal full scale in England (Simms et al.,
2000). A pilot-scale study for activated alumina was also conducted on
that water and showed run lengths much longer than observed in pilot-
scale studies in the United States. Due to the lack of published data
showing performance for a range of water qualities, granular ferric
hydroxide was not designated a BAT. In addition, there is little
published information on the cost of the media, so it is difficult to
evaluate cost. Granular ferric hydroxide is being investigated in
several ongoing studies and may be an effective technology for removing
arsenic. Systems may wish to investigate it and other adsorption
technologies such as modified activated alumina and other iron-based
media. Many of these other new adsorptive media are also being
investigated in several ongoing studies.
5. Waste disposal
Waste disposal will be an important issue for both large and small
drinking water plants. Costs for waste disposal have been added to the
costs of the treatment technologies (in addition to any pre-oxidation
and corrosion control costs), and form part of the treatment trains
that are listed in Tables I.G-1, I.G-5, and I.G-6.
The preamble to the proposed rule summarized toxicity
characteristic leaching procedure (TCLP) data on residuals from
different arsenic removal
[[Page 6984]]
technologies. The arsenic concentrations in TCLP extracts from alum
coagulation, activated alumina, lime softening, iron/manganese removal,
and coagulation-microfiltration residuals were below 0.05 mg/L, which
is two orders of magnitude lower than the current TC regulatory level.
The TCLP data for iron coagulation were mixed--the residuals from an
arsenic removal plant were below 0.05 mg/L, but the residuals from
another iron coagulation plant were above 1 mg/L. However, this is
still below the TC regulatory level of 5 mg/L. Based on these data, EPA
does not believe that drinking water treatment plant residuals would be
classified as hazardous waste. The TCLP data also indicate that most
residuals could meet a much lower TC regulatory level. Options where
the brine stream could be hazardous were eliminated from the final
decision tree. For the purposes of the national cost estimate, it was
assumed that solid residuals would be disposed of at nonhazardous
landfills.
G. Treatment Trains Considered For Small Systems
1. Can my water system use point-of-use (POU), point-of-entry (POE), or
bottled water to comply with this regulation?
Section 1412(b)(4)(E)(ii) of SDWA, as amended in 1996, requires EPA
to issue a list of technologies that achieve compliance with MCLs
established under the Act that are affordable and applicable to typical
small drinking water systems. These small public water systems
categories are: (1) population of more than 25 but less than or equal
to 500; (2) population of more than 500, but less than or equal to
3,300; and (3) population of more than 3,300, but less than or equal to
10,000. Owners and operators may choose any technology or technique
that best suits their conditions, as long as the MCL is met.
The technologies examined for BAT determinations were also
evaluated as small system compliance technologies. Several other
alternatives that are solely small system options were also evaluated
as compliance technologies. Central treatment is not the only option
available to small systems. One of the provisions included in the SDWA
Amendments of 1996 allows the use of POU and POE devices as compliance
technologies for small systems. SDWA stipulates that POU/POE treatment
systems:
shall be owned, controlled and maintained by the public water system
or by a person under contract with the public water system to ensure
proper operation and maintenance and compliance with the MCL or
treatment technique and equipped with mechanical warnings to ensure
that customers are automatically notified of operational problems
(Sec. 1412(b)(4)(E)).
Whole-house, or POE treatment, is necessary when exposure to the
contaminant by modes other than consumption is a concern; this is not
the case with arsenic. Single faucet, or POU treatment, is preferred
when treated water is needed only for drinking and cooking purposes.
POU devices are especially applicable for systems that have a large
flow and only a minor part of that flow directed for potable use such
as at many NTNCWSs. POE/POU options include reverse osmosis, activated
alumina, and ion exchange processes. POU systems are easily installed
and can be easily operated and maintained. In addition, these systems
generally offer lower capital costs and may reduce engineering, legal,
and other fees associated with centralized treatment options. However,
there will be higher administrative costs associated with POU and POE
options. For POU options, the trade-off is lower treatment cost since
only 1% of the water is treated, but higher administrative and
monitoring costs occur. Centrally managed POU options, even with the
higher monitoring and administrative costs, are less expensive than
central treatment for populations up to 150 to 250 people depending
upon the technology and number of households.
Using POU/POE devices introduces some new issues. Adopting a POU/
POE treatment system in a small community requires more record-keeping
to monitor individual devices than does central treatment. POU/POE
systems may require special regulations regarding customer
responsibilities as well as water utility responsibilities. The water
system or person under contract to the system is responsible for
maintaining the devices in customers' homes. This responsibility cannot
be delegated to the customer. Use of POU/POE systems does not reduce
the need for a well-maintained water distribution system. Increased
monitoring may be necessary to ensure that the treatment units are
operating properly. Monitoring POU/POE systems is also more complex
because compliance samples need to be taken after each POU or POE unit
rather than at the entry point to the distribution system to be
reflective of treatment.
EPA examined three technologies as POU and POE devices for the
proposed rule. EPA assumed that systems would more likely choose to use
POU activated alumina (AA) or reverse osmosis (RO), and POE AA in the
proposed rule. POU and POE ion exchange (IX) and POE RO were
considered, but not included as compliance technologies in the proposed
rule. Activated alumina and ion exchange units face a breakthrough
issue. If the activated alumina is not replaced on time, there is a
potential for significantly reduced arsenic removal. However, if the
anion exchange resin is not replaced or regenerated on time, the
previously removed arsenic can be driven off the resin by sulfate. Tap
water arsenic concentrations can be higher than the source water. This
is called chromatographic peaking. Due to the potential for
chromatographic peaking and run lengths that would typically be less
than six months, anion exchange was not listed as a compliance
technology in the proposed rule. POE ion exchange also may present
problems with total dissolved solids since the resin would need to be
regenerated. Since all sites within the system would need treatment,
the total dissolved solids increase from a centrally managed POE ion
exchange system would be similar to that from a central treatment ion
exchange system. EPA did not list POE RO units as compliance
technologies because it could create corrosion control problems. In
addition, water recovery would be no higher than central treatment, so
water quantity issues associated with central treatment reverse osmosis
would be applicable to POE RO.
The proposed rule included POE AA as a small system compliance
technology. Arsenic removal by AA is very sensitive to the pH. The
finished water pH will typically be higher than the optimal pH of 6 to
meet the corrosion control requirements of the lead and copper rule. A
finished water pH for many systems would be in the range of pH 7 to pH
8. Using data on activated alumina run length and pH, it was determined
that viable run lengths were likely only when the finished water pH was
at or below pH 7.5 (Kempic, 2000). Even in this pH range, the media may
need to be replaced more frequently than once a year, which would make
the option very expensive especially compared to the POU AA option. The
run length data used for this analysis were from a site with very
little competing ions (Simms and Azizian, 1997). Studies at other sites
with higher levels of competing ions have much lower run lengths
(Clifford et al., 1998). Based on the limited finished water pH range
where POE AA might be effective and the fact that the POU media needs
replacing much less frequently due to lower water demand, POE AA has
not been listed as a compliance technology
[[Page 6985]]
in the final rule. POE devices utilizing media that are less sensitive
to pH adjustment may be listed as compliance technologies in the future
once data on their performance are generated.
The effect of pH was also examined on POU AA. Under the POU AA
option, the volume of water requiring treatment is much smaller. The
unit will be installed at the kitchen tap and only the water being used
for cooking and consumption is being treated for arsenic removal. Since
the ratio of the daily volume of water being treated to the size of the
unit is much smaller, POU units can be operated for longer periods of
time before the media needs to be replaced. The replacement frequency
assumed for the costs is every six months. Viable run lengths for the
POU option were greater than one year up to pH 8 (Kempic, 2000). This
analysis assumed a large daily usage volume of 24 liters per day. The
average consumption per person per day is just over 1 liter. Even if
competing ions reduced the run length significantly, systems with tap
water at or below pH 8 should meet the MCL of 10 µg/L using a
six-month replacement frequency for the media. POU AA is a compliance
technology when the tap water pH is at or below pH 8.
POU RO was listed as a compliance technology in the proposed rule
and it is being listed as a compliance technology in the final rule as
well. Several comments indicated that water rejection would be an issue
with POU devices. Since only about 1% of the total water used in the
household is being treated, POU RO is unlikely to create water quantity
problems. If the water rejection rate was 10:1, this would only
increase the total household water demand by about 10 percent. Where
availability of additional water is limited, systems may want to
consider other alternatives to meet the MCL.
In order to be consistent with 1996 SDWA Amendments, EPA issued a
Federal Register notice on June 11, 1998 (EPA, 1998f) that deleted the
prohibition on the use of POU devices as compliance technologies. This
prohibition was in 40 CFR 141.101. This section now states that public
water systems shall not use bottled water to achieve compliance with an
MCL. Bottled water may be used on a temporary basis to avoid
unreasonable risk to health. Therefore, bottled water cannot be used as
a compliance technology for the arsenic rule.
Likely treatment trains are shown in Table I.G-1. These trains
represent a wide variety of solutions, including BATs, that small
systems may consider when complying with the proposed arsenic MCL. Not
all solutions may be viable for a given system. For example, only those
systems with coagulation/filtration in place will be able to modify
their existing treatment system. The treatment trains include BATs,
waste disposal, and when necessary, pre-oxidation and corrosion
control. While systems could install lime softening at pH > 10.5 or
optimized coagulation/filtration solely for arsenic removal, EPA does
not view this as a likely option. Reverse osmosis and electrodialysis
reversal are also not included in this table because other options are
more cost effective for arsenic removal and do not reject a large
volume of water like these two technologies. RO and EDR may be cost-
effective options if removal of other contaminants is needed and water
quantity is not a concern.
Table I.G-1.-- Treatment Technology Trains for Consideration by Small
Systems in Complying With Final Rule Including BATs
------------------------------------------------------------------------
Treatment Technology Trains for
Train # Consideration by Small Systems
------------------------------------------------------------------------
1............................ Add pre-oxidation [if not in-place] and
modify in-place Lime Softening (pH >
10.5) and modify corrosion control.
2............................ Add pre-oxidation [if not in-place] and
modify in-place Coagulation/Filtration
and modify corrosion control.
3............................ Add pre-oxidation [if not in-place] and
add Anion Exchange and add POTW waste
disposal. Sulfate level <= 20
mg/L.
4............................ Add pre-oxidation [if not in-place] and
add Anion Exchange and add POTW waste
disposal. Sulfate level: 20 mg/L
sulfate <= 50 mg/L.
5............................ Add pre-oxidation [if not in-place] and
add Coagulation Assisted Microfiltration
with corrosion control and add
mechanical dewatering/non-hazardous
landfill waste disposal.
6............................ Add pre-oxidation [if not in-place] and
add Coagulation Assisted Microfiltration
with corrosion control and add non-
mechanical dewatering/non-hazardous
landfill waste disposal.
7............................ Add Oxidation/Filtration (Greensand)
(20:1 iron: arsenic) and add POTW for
backwash stream.
8............................ Add pre-oxidation [if not in-place] and
add Activated Alumina and add non-
hazardous landfill (for spent media)
waste disposal. pH 7 <= pH pH
8.
9............................ Add pre-oxidation [if not in-place] and
add Activated Alumina and add non-
hazardous landfill (for spent media)
waste disposal. pH 8 <= pH
<= pH 8.3.
10........................... Add pre-oxidation [if not in-place] and
add Activated Alumina with pH adjustment
(to pH 6) and corrosion control and add
non-hazardous landfill (for spent media)
waste disposal. Run length = 23,100 BV.
11........................... Add pre-oxidation [if not in-place] and
add Activated Alumina with pH adjustment
(to pH 6) and corrosion control and add
non-hazardous landfill (for spent media)
waste disposal. Run length = 15,400 BV.
12........................... Add pre-oxidation [if not in-place] and
add POU Reverse Osmosis.
13........................... Add pre-oxidation [if not in-place] and
add POU Activated Alumina. (Finished
water pH <= pH 8.0)
------------------------------------------------------------------------
Pre-oxidation costs are given as a separate component because they
will be incurred only by some systems. In estimating national costs, it
was assumed that only systems without pre-oxidation in place would need
to add the necessary equipment. It is expected that no surface water
systems will need to install pre-oxidation for arsenic removal and that
fewer than 50% of the ground water systems may need to install pre-
oxidation for arsenic removal. Ground water systems without pre-
oxidation should ascertain if pre-oxidation is necessary by determining
if the arsenic is present as As (III) or As (V). Ground water systems
with predominantly As (V) will probably not need pre-oxidation to meet
the MCL.
2. What are the affordable treatment technologies for small systems?
The 13 treatment trains listed in Table I.G-1 were compared against
the national-level affordability criteria to determine the affordable
treatment trains. The Agency's national-level affordability criteria
were published in the August 6, 1998 Federal Register (EPA, 1998h). In
this notice, EPA discussed the procedure for affordable
[[Page 6986]]
treatment technology determinations for the contaminants regulated
before 1996.
The preamble to the proposed arsenic rule described the derivation
of the national-level affordability criteria (65 FR 38888 at 38926;
EPA, 2000i). A very brief summary follows: First an ``affordability
threshold'' (i.e., the total annual household water bill that would be
considered affordable) was calculated. The total annual water bill
includes costs associated with water treatment, water distribution, and
operation of the water system. In developing the threshold of 2.5%
median household income, EPA considered the percentage of median
household income spent by an average household on comparable goods and
services and on cost comparisons with other risk reduction activities
for drinking water such as households purchasing bottled water or a
home treatment device. The complete rationale for EPA's selection of
2.5% as the affordability threshold is described in ``Variance
Technology Findings for Contaminants Regulated Before 1996'' (EPA,
1998l).
The Variance Technology Findings document also describes the
derivation of the baselines for median household income, annual water
bills, and annual household consumption. Data from the Community Water
System Survey (CWSS) were used to derive the annual water bills and
annual water consumption values for each of the three small system size
categories. The Community Water System Survey data on zip codes were
used with the 1990 Census data on median household income to develop
the median household income values for each of the three small-system
size categories. The median household-income values used for the
affordable technology determinations are not based on the national
median income. The value for each size category is a national median
income for communities served by small water systems within that range.
Table I.G-2 presents the baseline values for each of the three small-
system size categories. Annual water bills and median household income
are based on 1995 estimates.
Table I.G-2.--Baseline Values for Small Systems Categories
----------------------------------------------------------------------------------------------------------------
Annual household
System size category (population consumption (1000 Annual water bills ($/ Median household income
served) gallons/yr) yr) ($)
----------------------------------------------------------------------------------------------------------------
25-500............................... 72 $211 $30,785
501-3,300............................ 74 184 27,058
3,300-10,000......................... 77 181 27,641
----------------------------------------------------------------------------------------------------------------
For each size category, the threshold value was determined by
multiplying the median household income by 2.5%. The annual household
water bills were subtracted from this value to obtain the available
expenditure margin. Projected treatment costs will be compared against
the available expenditure margin to determine if there are affordable
compliance technologies for each size category. The available
expenditure margin for the three size categories is presented in Table
I.G-3.
Table I.G-3.--Available Expenditure Margin for Affordable Technology
Determinations
------------------------------------------------------------------------
Available expenditure
System size category (population served) margin ($/household/
year)
-----------------------------------------------------------------------
25-500....................................... 559
501-3,300.................................... 492
3,301-10,000................................. 510
------------------------------------------------------------------------
The size categories specified in SDWA for affordable technology
determinations are different than the size categories typically used by
EPA in the Economic Analysis. A weighted average procedure was used to
derive design and average flows for the 25-500 category using design
and average flows from the 25-100 and 101-500 categories. A similar
approach was used to derive design and average flows from the 501-1000
and 1001-3300 categories for the 501-3300 category. The Variance
Technology Findings document (EPA, 1998l) describes this procedure in
more detail. Table I.G-4 lists the design and average flows for the
three size categories.
Table I.G-4.-- Design and Average Daily Flows Used for Affordable
Technology Determinations
------------------------------------------------------------------------
System size category (population Design flow Average flow
served) (mgd) (mgd)
------------------------------------------------------------------------
25-500............................ 0.058 0.015
501-3,300......................... 0.50 0.17
3,301-10,000...................... 1.8 0.70
------------------------------------------------------------------------
Capital and operating and maintenance costs were derived for each
treatment train using the flows listed previously and the cost
equations in the Technology and Cost Document. Several conservative
assumptions were made to derive the costs. The influent arsenic
concentration was assumed to be 50 µg/L, which was the MCL for
arsenic prior to this rule. The treatment target was 8 µg/L,
which is 80% of the MCL. Thus, little blending could be performed to
reduce costs. Capital costs were amortized using the 7% interest rate
preferred by OMB for benefit-cost analyses of government programs and
regulations rather than a 3% interest rate.
The annual system treatment cost in dollars per year was converted
into a rate increase using the average daily flow. The annual water
consumption values listed in Table I.G-2 were multiplied by 1.15 to
account for water lost due to leaks. Since the water lost to leaks is
not billed, the water bills for the actual water used were adjusted to
cover this lost water by increasing the household consumption. The rate
increase in dollars per thousand gallons used was multiplied by the
adjusted annual consumption to determine the annual cost increase for
the household for each treatment train. Several comments on
affordability presented household cost increases that were
[[Page 6987]]
derived by dividing the annual system cost by the number of households.
That is an inappropriate method because residential customers would not
only be paying for the water that they use, but also all the water used
by non-residential customers of the system..
Of the 13 treatment trains in Table I.G-1, the ones identified in
Table I.G-5 are deemed to be affordable for systems serving 25-500
people as the annual household cost was below the available expenditure
margin. The two trains using coagulation-assisted microfiltration are
not affordable for this size category. All 13 treatment trains are
deemed to be affordable for systems serving 501-3,300 and 3,301-10,000
people and are presented in Table I.G-6. Centralized compliance
treatment technologies include ion exchange, activated alumina,
modified coagulation/filtration, modified lime softening, and
oxidation/filtration (e.g. greensand filtration) for source waters high
in iron. In addition, POU and POE devices are also compliance
technology options for the smaller systems.
Table I.G-5.-- Affordable Compliance Technology Trains for Small Systems
With Population 25-500
------------------------------------------------------------------------
Train No. Treatment Technology Trains
------------------------------------------------------------------------
1............................ Add pre-oxidation [if not in-place] and
modify in-place Lime Softening (pH >
10.5) and modify corrosion control.
2............................ Add pre-oxidation [if not in-place] and
modify in-place Coagulation/Filtration
and modify corrosion control.
3............................ Add pre-oxidation [if not in-place] and
add Anion Exchange and add POTW waste
disposal. Sulfate level <= 20
mg/L.
4............................ Add pre-oxidation [if not in-place] and
add Anion Exchange and add POTW waste
disposal. Sulfate level: 20 mg/L
sulfate <= 50 mg/l.
7............................ Add Oxidation/Filtration (Greensand)
(20:1 iron: arsenic) and add POTW for
backwash stream.
8............................ Add pre-oxidation [if not in-place] and
add Activated Alumina and add non-
hazardous landfill (for spent media)
waste disposal. pH 7 <=pH pH
8.
9............................ Add pre-oxidation [if not in-place] and
add Activated Alumina and add non-
hazardous landfill (for spent media)
waste disposal. pH 8 <= pH
<= pH 8.3.
10........................... Add pre-oxidation [if not in-place] and
add Activated Alumina with pH adjustment
(to pH 6) and corrosion control and add
non-hazardous landfill (for spent media)
waste disposal. Run length = 23,100 BV.
11........................... Add pre-oxidation [if not in-place] and
add Activated Alumina with pH adjustment
(to pH 6) and corrosion control and add
non-hazardous landfill (for spent media)
waste disposal. Run length = 15,400 BV.
12........................... Add pre-oxidation [if not in-place] and
add POU Reverse Osmosis.
13........................... Add pre-oxidation [if not in-place] and
add POU Activated Alumina. (Finished
water pH <= pH 8.0)
------------------------------------------------------------------------
Table I.G-6.-- Affordable Compliance Technology Trains for Small Systems
With Populations 501-3,300 and 3,301 to 10,000
------------------------------------------------------------------------
Train No. Treatment Technology Trains
------------------------------------------------------------------------
1............................ Add pre-oxidation [if not in-place] and
modify in-place Lime Softening (pH >
10.5) and modify corrosion control.
2............................ Add pre-oxidation [if not in-place] and
modify in-place Coagulation/Filtration
and modify corrosion control.
3............................ Add pre-oxidation [if not in-place] and
add Anion Exchange and add POTW waste
disposal. Sulfate level <= 20
mg/L.
4............................ Add pre-oxidation [if not in-place] and
add Anion Exchange and add POTW waste
disposal. Sulfate level: 20 mg/L
sulfate <= 50 mg/l.
5............................ Add pre-oxidation [if not in-place] and
add Coagulation Assisted Microfiltration
with corrosion control and add
mechanical dewatering/non-hazardous
landfill waste disposal.
6............................ Add pre-oxidation [if not in-place] and
add Coagulation Assisted Microfiltration
with corrosion control and add non-
mechanical dewatering/non-hazardous
landfill waste disposal.
7............................ Add Oxidation/Filtration (Greensand)
(20:1 iron: arsenic) and add POTW for
backwash stream.
8............................ Add pre-oxidation [if not in-place] and
add Activated Alumina and add non-
hazardous landfill (for spent media)
waste disposal. pH 7 <=pH pH
8.
9............................ Add pre-oxidation [if not in-place] and
add Activated Alumina and add non-
hazardous landfill (for spent media)
waste disposal. pH 8 <= pH
<= pH 8.3.
10........................... Add pre-oxidation [if not in-place] and
add Activated Alumina with pH adjustment
(to pH 6) and corrosion control and add
non-hazardous landfill (for spent media)
waste disposal. Run length = 23,100 BV.
11........................... Add pre-oxidation [if not in-place] and
add Activated Alumina with pH adjustment
(to pH 6) and corrosion control and add
non-hazardous landfill (for spent media)
waste disposal. Run length = 15,400 BV.
12........................... Add pre-oxidation [if not in-place] and
add POU Reverse Osmosis.
13........................... Add pre-oxidation [if not in-place] and
add POU Activated Alumina. (Finished
water pH <= pH 8.0)
------------------------------------------------------------------------
3. Can My Water System Get a Small System Variance From an MCL Under
Today's Rule?
Section 1415(e)(1) of SDWA allows States to grant variances to
small water systems (i.e., systems having 10,000 customers or less) in
lieu of complying with an MCL if EPA determines that there are no
nationally affordable compliance technologies for that system size/
water quality combination. The system must then install an EPA-listed
variance treatment technology (section 1412(b)(15)) that makes progress
toward the MCL, if not necessarily reaching it. EPA has determined that
affordable technologies exist for all three system size categories and
has therefore not identified a variance technology for any system size
or source water quality combination. Small system variances are not
available for the final arsenic MCL.
H. Can My System Get a General Variance or Exemption From the MCL Under
Today's Rule?
General variances may be granted in accordance with section
1415(a)(1)(A) of SDWA and EPA's regulations. General variances are
available to public water systems that have installed or agree to
install the BAT but, due to source water quality, are or will be unable
to comply with the national primary drinking water standard. The
general variance
[[Page 6988]]
provisions of SDWA are narrowly focused on addressing those rare
circumstances where some unusual characteristic of the source water
available to a system will result in less effective performance of the
BAT. Exemptions may be granted in accordance with section 1416(a) of
SDWA and EPA's regulations. Exemptions are designed to provide a system
facing compelling circumstances, such as economic hardship, additional
time to come into compliance.
Under section 1415(a)(1)(A) of the SDWA, a State that has primary
enforcement responsibility (primacy), or EPA as the primacy agency, may
grant variances from MCLs to those public water systems of any size
that cannot comply with the MCLs because of characteristics of the
water sources. The primacy agency may grant general variances to a
system on condition that the system install the best available
technology, treatment techniques, or other means, and provided that
alternative sources of water are not reasonably available to the
system. At the time this type of variance is granted, the State must
prescribe a schedule for compliance with its terms and may require the
system to implement additional control measures. Furthermore, before
EPA or the State may grant a general variance, it must find that the
variance will not result in an unreasonable risk to health (URTH) to
the public served by the public water system.
Under section 1413(a)(4), States that choose to issue general
variances must do so under conditions, and in a manner, that are no
less stringent than section 1415. Of course, a State may adopt
standards that are more stringent than the EPA's standards. EPA
specifies BATs for general variance purposes. EPA may identify as BAT
different treatments under section 1415 for variances other than the
BAT under section 1412 for MCLs. The BAT findings for section 1415 may
vary depending on a number of factors, including the number of persons
served by the public water system, physical conditions related to
engineering feasibility, and the costs of compliance with MCLs. In this
final rule, EPA is not specifying different BAT for variances under
section 1415(a).
Under section 1416(a), EPA or a State may exempt a public water
system from any requirements related to an MCL or treatment technique
of an NPDWR if it finds that: (1) Due to compelling factors (which may
include a variety of ``compelling'' factors, including economic factors
such as qualification of the PWS as serving a disadvantaged community),
the PWS is unable to comply with the requirement or implement measure
to develop an alternative source of water supply; (2) the exemption
will not result in an URTH; (3) the PWS was in operation on the
effective date of the NPWDR, or for a system that was not in operation
by that date, only if no reasonable alternative source of drinking
water is available to the new system; and (4) management or
restructuring changes (or both) cannot reasonably result in compliance
with the Act or improve the quality of drinking water.
If EPA or the State grants an exemption to a public water system,
it must at the same time prescribe a schedule for compliance (including
increments of progress or measures to develop an alternative source of
water supply) and implementation of appropriate control measures that
the State requires the system to meet while the exemption is in effect.
Under section 1416(b)(2)(A), the schedule prescribed shall require
compliance as expeditiously as practicable (to be determined by the
State), but no later than 3 years after the compliance date for the
regulations established pursuant to section 1412(b)(10). For public
water systems serving 3,300 people or less and needing financial
assistance for the necessary improvements, EPA or the State may renew
an exemption for one or more additional two-year periods, but not to
exceed a total of six years, if the system establishes that it is
taking all practicable steps to meet certain requirements specified in
the statute. Thus, the maximum possible duration of a small systems
exemption is nine years beyond the 5-year compliance schedule specified
in today's rule.
A public water system shall not be granted an exemption unless it
can establish that either: (1) The system cannot meet the standard
without capital improvements that cannot be completed prior to the date
established pursuant to section 1412(b)(10); (2) in the case of a
system that needs financial assistance for the necessary
implementation, the system has entered into an agreement to obtain
financial assistance pursuant to section 1452 or any other Federal or
State program; or (3) the system has entered into an enforceable
agreement to become part of a regional public water system.
EPA believes that exemptions will be an important tool to help
States address the number of systems needing financial assistance to
achieve compliance with the arsenic rule (and other rules) with the
available supply of financial assistance. About 2,300 CWSs and about
1,100 NTNCWSs will need to install treatment to achieve compliance with
today's final rule. CWSs and not-for-profit NTNCWSs are eligible for
assistance from the Drinking Water State Revolving Fund (DWSRF).
Between its inception in Federal Fiscal Year 1997 and June 2000, the
DWSRF program has provided assistance to about 1,100 systems. Given the
many competing demands being placed on financial assistance programs,
the ability to extend the period of time available for a system to
receive financial assistance will provide important flexibility for
States and systems. Exemptions provide an opportunity to extend the
period of time during which a system can achieve compliance, thus
providing needy systems with additional time to qualify for financial
assistance. Under today's action, all systems have 5 years to achieve
compliance. Exemptions for an additional 3 years can be made available
to qualified systems. For those qualified systems serving 3,300 persons
or less, up to 3 additional 2-year extensions to the exemption are
possible, for a total exemption duration of 9 years. When added to the
5 years provided for compliance by the rule, this allows up to 14 years
for small systems serving up to 3,300 people to achieve compliance.
EPA will issue guidance in the near future on considerations
involved in granting exemptions under the arsenic rule, including
making findings of no URTH where exemptions are offered.
I. What Analytical Methods are Approved for Compliance Monitoring of
Arsenic and What are the Performance Testing Criteria for Laboratory
Certification?
1. Approved Analytical Methods
Today's rule lists four analytical technologies that are approved
for compliance determinations of arsenic at the MCL of 0.01 mg/L (see
Table I.I-1). As noted in the June 22, 2000 proposed rule (65 FR 38888,
EPA, 2000i), the methods listed in Table I.I-1 are the same analytical
technologies that were approved for arsenic when the MCL was 0.05 mg/L,
with the exception of the methods that use Inductively Coupled Plasma
Atomic Emission Spectroscopy (ICP-AES) measurement technology. EPA is
withdrawing two ICP-AES methods (EPA Method 200.7 and SM 3120B) because
their detection limits (0.008 mg/L and 0.050 mg/L respectively) are too
high to reliably determine compliance with an MCL of 0.01 mg/L. In the
June 2000 proposed rule, EPA noted that the ICP-AES methods were rarely
used to obtain laboratory certification when analyzing
[[Page 6989]]
low level challenge samples for arsenic. Therefore, we believe
withdrawal of the availability of the ICP-AES methods for compliance
determinations of arsenic in drinking water will not affect laboratory
capacity. EPA did not receive any adverse comment on the proposal to
withdraw approval of these two methods, and today's final rule amends
the CFR to effect this withdrawal.
Table I.I-1.--Approved Analytical Methods (40 CFR 141.23) for Arsenic at
the MCL of 0.01 mg/L
------------------------------------------------------------------------
Methodology Reference method
------------------------------------------------------------------------
Inductively Coupled Plasma Mass 200.8 (EPA)
Spectroscopy (ICP-MS).
Stabilized Temperature Platform 200.9 (EPA)
Graphite Furnace Atomic Absorption
(STP-GFAA).
Graphite Furnace Atomic Absorption 3113B (SM) D-2972-93C (ASTM)
(GFAA).
Gaseous Hydride Atomic Absorption 3114B (SM) D-2972-93B (ASTM)
(GHAA).
------------------------------------------------------------------------
2. Performance Testing Criteria for Laboratory Certification
For purposes of drinking water laboratory certification, the Agency
specifies pass/fail (acceptance) limits for a successful analysis of
the required annual challenge sample, i.e., a performance evaluation
(PE) or performance testing (PT) sample. These acceptance limits have
been historically derived using one of two different approaches:
(a) Variable acceptance limits uniquely derived for each PE
study from a regression analysis of the performance of all
laboratories that participate in that PE-study, or
(b) Fixed acceptance limits derived from a regression analysis
of the laboratory PE sample analysis results in several PE studies.
Variable acceptance limits are analogous to ``grading on a curve''
which means that the pass/fail limit can vary from PE study to study
depending on the quality and experience of the laboratories
participating in the study. These limits are specified in the CFR as
plus or minus two sigma (2 ) where sigma is the standard deviation of
the analytical results reported in the PE study. EPA specifies variable
acceptance limits when a method or measurement technology is new enough
that an insufficient number of experienced laboratories have
participated in the PE studies or when only a few PE studies have been
conducted.
EPA prefers the fixed acceptance limits approach because it is the
better indicator of laboratory performance averaged over time and
several different concentrations of the target analyte. Fixed limits
also provide the same pass/fail benchmark in each PE study. As
discussed in the proposed rule, EPA has a large base of PE-study data
from which to derive a practical quantitation limit (PQL) and a fixed
PE-study acceptance limit for arsenic. Thus, as proposed in the June
2000 rule, today's final rule amends Sec. 141.23(k)(3)(ii) to specify
an acceptance limit of ±30% in PE (now known as PT) samples
spiked with arsenic at the PQL of 0.003 mg/L or greater. For a brief
discussion of the derivation of the PQL for arsenic, see section
III.B.1, What is the feasible level?
J. How Will I Know if My System Meets the Arsenic Standard?
This section summarizes changes to the arsenic monitoring and
compliance determination requirements. The Agency is also changing the
methods used by a system to determine if it is in violation of an MCL
for all of the regulated inorganic contaminants (IOCs), synthetic
organic contaminants (SOCs), and volatile organic contaminants (VOCs).
See section I.J.3. for more information regarding violation
determinations.
1. Sampling Points and Grandfathering of Monitoring Data
In today's rule, the Agency is moving the requirements associated
with arsenic into Sec. 141.23(c) making it consistent with the
requirements for IOCs regulated under the standardized monitoring
framework. All CWS and NTNCWSs must monitor for arsenic at each entry
point to the distribution system. In some cases, Sec. 142.11(1) allows
States to establish regulations that ``vary from comparable regulations
set forth in part 141 of this chapter, and demonstrate that any
different State regulation is at least as stringent as the comparable
regulation contained in part 141.'' Using this authority, States may
allow systems to collect samples at an alternative location (e.g., the
first point of drinking water consumption in the distribution system)
if the State justifies in its primacy program that the alternative
location is equally or more protective. States could implement the
change in sampling location once the primacy package is approved.
The MCL compliance elements of the rule become effective in 2006.
Some ground water systems will collect samples to comply with the
sampling requirements for all regulated IOCs (including arsenic) in
2005 in accordance with the State monitoring plan. This sampling event
will satisfy the monitoring requirements for the 2005-2007 compliance
period, but the revised arsenic MCL will not become effective until
2006. Ground water systems may use grandfathered data collected after
January 1, 2005 to satisfy the sampling requirements for the 2005-2007
compliance period. The grandfathered data must report results from
analytical methods approved for use by this final rule (e.g., the
method detection limit must be substantially less than the revised MCL
of 10 µg/L). Data collected using unacceptably high detection
levels (e.g. using ICP-AES technology) will not be eligible for
grandfathering. If the grandfathered data are used to comply with the
2005-2007 compliance period and the analytical result is greater than
10 µg/L, that system will be in violation of the revised MCL on
the effective date of the rule. If systems do not use grandfathered
data, then surface water systems must collect a sample by December 31,
2006 and ground water systems must collect a sample by December 31,
2007 to demonstrate compliance with the revised MCL.
2. Compositing of Samples
Compositing of samples is allowed under the standardized monitoring
framework. The States that allow compositing of samples use the
methodology in the Phase II/V regulations as specified in
Sec. 141.23(a)(4). In today's rule, CWSs and NTNCWSs will still be
allowed to composite samples; however, if arsenic is detected above
one-fifth of the revised MCL (2 µg/L), then a follow-up sample
must be taken within 14 days at each sampling point included in the
composite as described in Sec. 141.23(a)(4). Compliance determinations
must be based on the follow up sample result. Water systems may
composite samples (temporally and spatially) until a
[[Page 6990]]
contaminant (arsenic or any other contaminant regulated in the Phase
II/V regulations) is detected. Once a contaminant has been detected in
a composited sample at concentrations greater than one-fifth of the
MCL, the system(s) must discontinue the practice of compositing samples
for all future monitoring.
3. Calculation of Violations
In today's rule, the Agency is clarifying the compliance
determination section for the IOCs (including arsenic), the SOCs, and
the VOCs in Secs. 141.23(i), 141.24(f)(15), and 141.24(h)(11),
respectively.
Systems will determine compliance based on the analytical result(s)
obtained at each sampling point. If any sampling point is in violation
of an MCL, the system is in violation. For systems monitoring more than
once per year, compliance with the MCL is determined by a running
annual average at each sampling point. Systems monitoring annually or
less frequently whose sample result exceeds the MCL for any inorganic
contaminant in Sec. 141.23(c), or whose sample results exceeds the
trigger level for any organic contaminant listed in Sec. 141.24(f) or
Sec. 141.24(h), must revert to quarterly sampling for that contaminant
the next quarter. Systems are only required to conduct quarterly
monitoring at the entry point to the distribution system at which the
sample was collected and for the specific contaminant that triggered
the system into the increased monitoring frequency. Systems triggered
into increased monitoring will not be considered in violation of the
MCL until they have completed one year of quarterly sampling. If any
sample result will cause the running annual average to exceed the MCL
at any sampling point (i.e., the analytical result is greater than four
times the MCL), the system is out of compliance with the MCL
immediately. Systems may not monitor more frequently than specified by
the State to determine compliance unless they have applied to and
obtained approval from the State. If a system does not collect all
required samples when compliance is based on a running annual average
of quarterly samples, compliance will be based on the running annual
average of the samples collected. If a sample result is less than the
method detection limit, zero will be used to calculate the annual
average. States have the discretion to delete results of obvious
sampling or analytic errors.
States still have the flexibility to require confirmation samples
for positive or negative results. States may require more than one
confirmation sample to determine the average exposure over a 3-month
period. Confirmation samples must be averaged with the original
analytical result to calculate an average over the 3-month period. The
3-month average must be used as one of the quarterly concentrations for
determining the running annual average. The running annual average must
be used for compliance determinations.
The rule requires that monitoring be conducted at all entry points
to the distribution system. However, the State has discretion to
require monitoring and determine compliance based on a case-by-case
analysis of individual drinking water systems. The Agency cannot
address all of the possible outcomes that may occur at a particular
water system; therefore, EPA encourages drinking water systems to
inform State regulators of their individual circumstances. Some systems
have implemented elaborate plans including targeted, increased
monitoring that is more representative of the average annual
contaminant concentration to which individuals are being exposed (some
States use a time-weighted or flow-weighted averaging approach to
determine compliance).
Some States require that systems collect samples from wells that
only operate for one month out of the year regardless of whether they
are operating during scheduled sampling times. The State may determine
compliance based on several factors including, but not limited to, the
quantity of water supplied by a source, the duration of service of the
source, and contaminant concentration.
4. Monitoring and Compliance Schedule
Systems must begin complying with the clarified monitoring and
compliance determination provisions of today's rule effective January
22, 2004 for inorganic, volatile organic, and synthetic organic
contaminants. These requirements clarify that for Secs. 141.23(i)(2),
141.24(f)(15)(ii), and 141.24(h)(11)(ii) compliance will be determined
based on the running annual average of the initial MCL exceedance and
any subsequent State-required confirmation samples. In addition, the
clarifications address calculation of compliance when a system fails to
collect the required number of samples. Compliance (determined by the
average concentration) will be based on the total number of samples
collected. Some systems have purposely not collected the required
number of quarterly samples and only incurred monitoring and reporting
violations for the uncollected samples. Any systems that avoid required
sampling will calculate MCL violations by dividing the summed samples
by the actual number of samples taken. This clarification did not
change Secs. 141.23(i)(1) and 141.24(h)(11)(i) which allow systems to
use zero for all non-detects when calculating MCL violations. In
addition, if any one sample would cause the annual average to be
exceeded, the system is out of compliance immediately.
Also in today's rule, the Agency is moving the arsenic monitoring
and compliance requirements from Secs. 141.23(l) to (q) to the
standardized monitoring framework in Sec. 141.23 for other IOCs. States
may grant systems nine-year monitoring waivers using the conditions in
Sec. 141.23(c) for arsenic. The criteria for developing a State waiver
program were published in the Phase II/V rules, and as noted in section
IV.B. of this rule, the Agency is not modifying the waiver criteria in
today's rulemaking. However, the revised arsenic rule is not effective
until January 23, 2006 (see section I.M. for a more detailed discussion
regarding the effective date of the rule.). States and utilities
supported moving arsenic into the standardized monitoring framework.
To use compliance data after the effective date of the 10
µg/L MCL, systems must use an approved method with a method
detection limit substantially less than the revised arsenic MCL of 10
µg/L. This means that after December 31, 2006 and December 31,
2007 all surface water systems and groundwater systems, respectively,
may not use analytical methods using the ICP-AES technology, because
the detection limits for these methods are 8 µg/L or higher.
This restriction means that two ICP-AES methods that were approved when
the MCL was 50 µg/L may not be used for compliance
determinations at the revised MCL of 10 µg/L. The two methods
are EPA Method 200.7 and SM 3120B. Prior to 2005, systems may have
compliance samples analyzed with these less sensitive methods. However,
EPA advises systems to have compliance samples analyzed and reported at
the laboratory minimum detection limit.
If sampling demonstrates that arsenic exceeds the MCL, a CWS will
be triggered into quarterly monitoring for that sampling point ``in the
next quarter after the violation occurred.'' The State may allow the
system to return to the routine monitoring frequency when the State
determines that the system is reliably and consistently below the MCL.
However, the State cannot make a determination that the system is
reliably and consistently below the MCL until a
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minimum of two consecutive ground water, or four consecutive surface
water samples, have been collected (Sec. 141.23(c)(8)).
The Agency is not promulgating a reduced monitoring approach
similar to the revised radionuclides final rule published on December
7, 2000 (65 FR 76708; EPA, 2000p). As noted above, all systems have to
collect IOC samples once a year or once every three years, depending on
the source water, unless they have a waiver. The Agency believes that
very few States issue waivers for IOCs because the analysis is
relatively inexpensive and most IOCs are naturally occurring elements
that may be found in concentrations above the method detection limit.
Therefore, the majority of systems must collect routine samples for the
regulated IOCs; and most of the methods used for analysis of these
contaminants will measure arsenic as well as antimony, beryllium,
cadmium, chromium, copper, and nickel.
K. What do I Need to tell My Customers?
1. Consumer Confidence Reports
a. General requirements. In 1998, EPA promulgated the Consumer
Confidence Report Rule (CCR) (codified at 40 CFR part 141, subpart O),
a final rule requiring community water systems to issue annual water
quality reports to their customers (63 FR 44512; EPA, 1998i). The
reports are due each year by July 1, and provide a snapshot of water
quality over the preceding calendar year. The reports include
information on levels of detected contaminants and if the system has
violated an MCL or a treatment technique, must also include information
on the potential health effects of contaminants from appendix A to
subpart O. When they have such violations, systems must also include in
their report an explanation of the violation and remedial measures
taken to address it. The arsenic health effects language is currently
required when arsenic levels exceed 25 µg/L, one-half the
existing MCL of 50 µg/L, required under Sec. 141.154(b).
EPA is today retaining the health effects language for arsenic
issued with the final CCR Rule and updating appendix A to subpart O to
include the MCL and MCLG as revised in this rule, together with special
arsenic-specific reporting requirements.
In addition to the standard reporting of arsenic detects and
arsenic MCL violations, EPA is today finalizing a requirement (proposed
at Sec. 141.154(b); finalized at Sec. 141.154(f)) that CWSs that detect
arsenic between the revised and existing MCL (i.e., above 10
µg/L and up to and including 50 µg/L) prior to the
effective date for compliance with the revised MCL, include the CCR
Rule health effects language in their reports. This action is required
even though, technically, the systems are not in violation of the
regulations. This requirement will be effective for the five years
after promulgation, when systems are not yet required to comply with
the revised MCL. Then, beginning January 23, 2006, systems out of
compliance must report violations of the revise |
