Revisions to the Unregulated Contaminant Monitoring Regulation
for Public Water Systems
[Federal Register: September 17, 1999 (Volume 64, Number 180)]
[Rules and Regulations]
[Page 50555-50620]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr17se99-21]
[[Page 50555]]
_______________________________________________________________________
Part II
Environmental Protection Agency
_______________________________________________________________________
40 CFR Parts 9, 141 and 142
Revisions to the Unregulated Contaminant Monitoring Regulation for
Public Water Systems; Final Rule
[[Page 50556]]
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 9, 141 and 142
[FRL-6433-1]
RIN 2040-AD15
Revisions to the Unregulated Contaminant Monitoring Regulation
for Public Water Systems
AGENCY: Environmental Protection Agency.
ACTION: Final rule.
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SUMMARY: The Safe Drinking Water Act (SDWA), as amended in 1996,
requires the U.S. Environmental Protection Agency (EPA) to establish
criteria for a program to monitor unregulated contaminants and, by
August 6, 1999, to publish a list of contaminants to be monitored. To
conform to the Amendments, today EPA is promulgating the Unregulated
Contaminant Monitoring Regulation (UCMR) for Public Water Systems
(PWSs), which revises substantially the existing regulations for
unregulated contaminant monitoring.
This final rule includes a list of contaminants to be monitored,
procedures for selecting a representative nationwide sample of small
PWSs that will be required to monitor, the frequency and schedule for
monitoring, the sampling points, the approved analytical methods to be
used, and procedures for entering the monitoring data in the National
Drinking Water Contaminant Occurrence Database (NCOD), as required
under section 1445 of SDWA, as amended. The data in the database will
be used to identify contaminants on the Drinking Water Contaminant
Candidate List (CCL), to support the Administrator's determination of
whether or not to develop drinking water standards for a particular
contaminant, and to develop standards for the contaminants that the
Administrator selects.
DATES: Effective Date: The final rule is effective January 1, 2001.
For purposes of judicial review, this final rule is promulgated as
on 1 p.m. Eastern time on October 1, 1999 as provided in 40 CFR 23.7.
The incorporation by reference of the publications listed in
today's rule is approved by the Director of the Federal Register as of
January 1, 2001.
ADDRESSES: Documents relevant to this action are available for
inspection from 9 a.m. to 4 p.m. Monday through Friday, excluding legal
holidays, at the Water Docket, East Tower Basement, U.S. EPA, 401 M
Street, SW, Washington DC. For access to docket (Docket No. W-98-02)
materials, please call (202) 260-3027 between 9 a.m. and 3:30 p.m,
Eastern Time, Monday through Friday, to schedule an appointment. A
reasonable fee may be charged for copying.
FOR FURTHER INFORMATION CONTACT: Charles Job, Standards and Risk
Management Division, Office of Ground Water and Drinking Water (MC-
4607), U.S. Environmental Protection Agency, 401 M Street, SW,
Washington, D.C. 20460, (202) 260-7084. General information may also be
obtained from the EPA Safe Drinking Water Hotline. Callers within the
United States may reach the Hotline at (800) 426-4791. The Hotline is
open Monday through Friday, excluding federal holidays, from 9:00 a.m.
to 5:30 p.m. Eastern Time.
SUPPLEMENTARY INFORMATION:
Regional Contacts
I. Jane Downing, JFK Federal Bldg., Room 2203, Boston, MA 02203.
Phone: 617-918-1571.
II. Bruce Kiselica, 290 Broadway, Room 2432, New York, NY 10007-
1866. Phone: 212-637-3879.
III. Michelle Hoover, 1650 Arch Street, Philadelphia, PA 19103-2029.
Phone: 215-814-5258.
IV. Janine Morris, 345 Courtland Street, NE, Atlanta, GA 30365.
Phone: 404-562-9480.
V. Thomas Poleck, 77 West Jackson Blvd., Chicago, IL 60604-3507.
Phone: 312-886-2407.
VI. Larry Wright, 1445 Ross Avenue, Dallas, TX 75202. Phone: 214-
665-7150.
VII. Stan Calow, 726 Minnesota Ave., Kansas City, KS 66101. Phone:
913-551-7410.
VIII. Rod Glebe, One Denver Place, 999 18th Street, Suite 500,
Denver, CO 80202. Phone: 303-312-6627.
IX. Bruce Macler, 75 Hawthorne Street, San Francisco, CA 94105.
Phone: 415-744-1884.
X. Gene Taylor, 1200 Sixth Avenue, Seattle, WA 98101. Phone: 206-
553-1389.
Abbreviations and Acronyms Used in the Preamble and Final Rule
2,4-DNT--2,4-dinitrotoluene
2,6-DNT--2,6-dinitrotoluene
4,4'-DDE--4,4'-dichloro dichlorophenyl ethylene, a degradation
product of DDT
Alachlor ESA--alachlor ethanesulfonic acid, a degradation product of
alachlor
AOAC--Association of Official Analytical Chemists
APHA--American Public Health Association
ASDWA--Association of State Drinking Water Administrators
ASTM--American Society for Testing and Materials
BGM--Buffalo Green Monkey cells, a specific cell line used to grow
viruses
CAS--Chemical Abstract Service
CASRN--Chemical Abstract Service Registry Number
CCL--Contaminant Candidate List
CCR--Consumer Confidence Reports
CERCLA--Comprehensive Environmental Response, Compensation &
Liability Act
CFR--Code of Federal Regulations
CFU--colony forming unit
CFU/mL--colony forming units per milliliter
CWS--community water system
DCPA--dimethyl tetrachloroterephthalate, chemical name of the
herbicide dacthal
DCPA mono- and di-acid degradates--degradation products of DCPA
DDE--dichloro dichlorophenyl ethylene, a degradation product of DDT
DDT--dichloro diphenyl trichloroethane, a general insecticide
DNA--deoxyribonucleic acid
EDL--estimated detection limit
EPA--Environmental Protection Agency
EPTC--s-ethyl-dipropylthiocarbamate, an herbicide
EPTDS--Entry Point to the Distribution System
ESA--ethanesulfonic acid, a degradation product of alachlor
FACA--Federal Advisory Committee Act
FTE--full-time equivalent
GC--gas chromatography, a laboratory method
GLI method--Great Lakes Instruments method
GW--ground water
GWUDI--ground water under the direct influence (of surface water)
HPLC--high performance liquid chromatography, a laboratory method
ICR--Information Collection Request/Rule
IRFA--initial regulatory flexibility analysis
IMS--immunomagnetic separation
IRIS--Integrated Risk Information System
IS--internal standard
LLE--liquid/liquid extraction, a laboratory method
MAC--Mycobacterium avium complex
MOA--Memorandum of Agreement
MCL--maximum contaminant level
MDL--method detection limit
MRL--minimum reporting level
MS--mass spectrometry, a laboratory method
MSD--sample matrix spike duplicate
MTBE--methyl-tertiary-butyl-ether, a gasoline additive
NAWQA--National Water Quality Assessment Program
NCOD--National Drinking Water Contaminant Occurrence Database
NDWAC--National Drinking Water Advisory Council
NERL--National Environmental Research Laboratory
NPS--National Pesticide Survey
NTIS--National Technical Information Service
NTNCWS--non-transient non-community water system
NTTAA--National Technology Transfer and Advancement Act
OGWDW--Office of Ground Water and Drinking Water
OMB--Office of Management and Budget
PAH--Poly-aromatic hydrocarbon
PB--particle beam
PBMS--Performance-Based Measurement System
pCi/L--picocuries per liter
PCR--polymerase chain reaction
[[Page 50557]]
<SUP>210</SUP>Pb--Lead-210 (also Pb-210), a lead isotope and
radionuclide; part of the uranium decay series
<SUP>210</SUP>Po--Polonium-210 (also Po-210), a polonium isotope and
radionuclide; part of the uranium decay series
PWS--Public Water System
PWSF--Public Water System Facility
QA--quality assurance
QC--quality control
RDX--royal demolition explosive, hexahydro-1,3,5-trinitro-1,3,5-
triazine
RFA--Regulatory Flexibility Act
RPD--relative percent difference
RSD--relative standard deviation
SBREFA--Small Business Regulatory Enforcement Fairness Act
SD--standard deviation
SDWA--Safe Drinking Water Act
SDWIS--Safe Drinking Water Information System
SDWIS FED--the Federal Safe Drinking Water Information System
SM--Standard Methods
SMF--Standard Compliance Monitoring Framework
SMS--sample matrix spike
SOC--synthetic organic compound
SPE--solid phase extraction, a laboratory method
SRF--State Revolving Fund
STORET--Storage and Retrieval System
SW--surface water
TBD--to be determined
TNCWS--transient non-community water system
UCMR--Unregulated Contaminant Monitoring Regulation/Rule
UCM--Unregulated Contaminant Monitoring
UMRA--Unfunded Mandates Reform Act of 1995
USEPA--United States Environmental Protection Agency
UV--ultraviolet
VOC--volatile organic compound
<greek-m>g/L--micrograms per liter
Preamble Outline
I. Statutory Authority
II. Major Program Revisions
III. Regulatory Background
IV. Process of Preparing the Final Rule
V. Concise Description of Today's Action
A. Which Systems Must Monitor
B. System Monitoring Requirements
C. System Reporting Requirements
D. State and Tribal Participation
VI. Final Changes in the Unregulated Contaminant Monitoring Program
A. Revised List of Unregulated Contaminants to be Monitored
1. Criteria for Selecting Contaminants for the UCMR
(a) Revising the UCMR (1999) List
(b) Regulatory Approach for the UCMR (1999) List
(c) Analytical Methods Applicable to the UCMR (1999) List
(i) Chemical Analytical Methods
(ii) Microbiological Analytical Methods
2. List of Contaminants To Be Monitored
(a) Final UCMR (1999) List
(b) Number of Contaminants on the UCMR (1999) List
B. Public Water Systems Subject to the UCMR
C. Type of Monitoring Required of Public Water Systems Based on
Listing Group
1. Assessment Monitoring
2. Screening Survey
3. Pre-Screen Testing
D. Monitoring Requirements Under the Final UCMR
1. Monitoring Frequency
(a) Systems Serving More Than 10,000 Persons
(i) Chemical Contaminants.
(ii) Microbiological Contaminants.
(b) Systems Serving 10,000 or Fewer Persons
2. Monitoring Time for Vulnerable Period
3. Monitoring Location
(a) Chemical Contaminants
(b) Microbiological Contaminants
4. Quality Control Procedures for Sampling and Testing
5. Monitoring of Routinely Tested Water Quality Parameters
6. Relation to Compliance Monitoring Requirements
7. Previous Monitoring of the Contaminants on the Final UCMR
(1999) List
E. Waivers
1. Waivers for Systems Serving More than 10,000 Persons
2. Waivers for Small Systems in State Plans
F. Representative Sample of Systems Serving 10,000 or Fewer
Persons
1. System Size
2. System Type
(a) Public Water System Monitoring
(b) Nontransient Non-Community Water Systems
(c) Transient Non-Community Systems
3. Geographic Location
4. Likelihood of Finding Contaminants
5. State Plans for the Representative Sample
(a) Representative State Plans
(b) Systems Selected for Pre-Screen Testing
(c) Tribal Water Systems
(d) ``Index'' Systems
(e) Other State Data
G. Reporting of Monitoring Results
1. Reporting Requirements (Data Elements)
2. Reporting to the Primacy Agency
3. Timing of Reporting
4. Method of Reporting
5. Public Notification of Availability of Results
VII. Section-by-Section Analysis of Public Comment and EPA Response
A. Section 141.35--Reporting of Unregulated Contaminant
Monitoring Results
1. Does this reporting apply to me?
2. To whom must I report?
3. When do I report monitoring results?
4. What information must I report?
5. How must I report this information?
6. Can the laboratory to which I send samples report the results
for me?
7. Can I report previously collected data to meet the testing
and reporting requirements for the contaminants in
Sec. 141.40(a)(3)?
B. Sec. 141.40--Monitoring Requirements for Unregulated
Contaminants
1. Requirements for Owners and Operators of Public Water Systems
(a) Do I have to monitor for unregulated contaminants?
(b) How would I be selected for the monitoring under the State
Monitoring Plan, the screening survey, or the pre-screen testing?
(c) For which contaminants must I monitor?
(d) What general monitoring requirements must I follow for List
1 monitoring?
(e) What specific sampling and quality control requirements must
I follow for monitoring of List 1 contaminants?
(i) All systems
(ii) Large systems
(A) Timeframe
(B) Frequency
(C) Location
(D) Sampling instructions
(E) Testing and analytical methods
(F) Sampling deviations
(G) Testing
(iii) Small systems that are part of the State Monitoring Plan
(A) Frequency
(B) Location
(C) Sampling deviations
(D) Sample kits
(E) Sampling instructions
(F) Duplicate samples
(G) Sampling forms
(H) Sample submission
(f) What additional requirements must I follow if my system is
selected as an Index system?
(g) What must I do if my system is selected for the Screening
Survey or Pre-Screen Testing?
(h) What is a violation of this rule?
2. Requirements for State and Tribal Participation
(a) How can I as the director of a State or Tribal drinking
water program participate in unregulated contaminant monitoring,
including the State Monitoring Plan for small systems, and the
Screening Survey and Pre-Screen Testing of all systems?
(b) What if I decide not to enter into an MOA?
(c) Can I add contaminants to the Unregulated Contaminant
Monitoring List?
(d) Can I waive monitoring requirements?
C. Appendix A--Quality Control Requirements for Testing All
Samples Collected
D. Sec. 142.15--Reports by States
E. Sec. 142.16--Special primacy requirements
VIII. General Issues From Public Comment and EPA Response
A. Data Quality
B. EPA Funding for Small System Testing
C. Lab Certification
D. Research
E. Regulation Format
F. Voluntary Data Submittal
IX. Other Changes Related to the Regulation
A. Implementation of the Rule
1. Setting an Effective Date.
2. Analytical Methods for the Testing Program.
3. Testing Program for Large Systems.
4. Testing Program for Small Systems.
5. Continued Development of Analytical Methods.
6. Determining the Representative National Sample and State
Monitoring Plans.
[[Page 50558]]
7. Specifying the Vulnerable Monitoring Period.
8. Conducting the Sampling.
9. Establishing Sampling Points.
10. Large Systems.
11. Systems in State Monitoring Plans.
12. Screening Survey.
13. Pre-Screen Testing.
14. Testing.
15. Reporting Requirements.
16. Record Keeping.
17. Previously Collected Data.
18. Modifying the Monitoring List.
B. Implementation in Indian Country
C. Performance-based Measurement System
X. Guidance Manuals
XI Costs and Benefits of the Rule
A. Program Cost Estimates
1. Assumptions: Assessment Monitoring
2. Estimated Average Annual Cost for 5-Year Program: Assessment
Monitoring Only
B. Estimated Net Costs
C. Benefits
XII. Administrative Requirements
A. Executive Order 12866--Regulatory Planning and Review
B. Executive Order 13045--Protection of Children From
Environmental Health Risks and Safety Risks
C. Unfunded Mandates Reform Act
D. Paperwork Reduction Act
E. Regulatory Flexibility Act
1. Full Assessment Monitoring Implementation Scenario
2. Limited Implementation Scenario
F. National Technology Transfer and Advancement Act
G. Executive Order 12898--Federal Actions to Address
Environmental Justice in Minority Populations and Low-Income
Populations
H. Federalism Executive Orders
I. Executive Order 13084--Consultation and Coordination with
Indian Tribal Governments
J. Congressional Review Act
XIII. Public Involvement in Regulation Development
XIV. References
Potentially Regulated Entities
The regulated entities are public water systems. All large
community and non-transient non-community water systems serving more
than 10,000 persons are required to monitor. A community water system
(CWS) means a public water system which serves at least 15 service
connections used by year-round residents or regularly serves at least
25 year-round residents. Non-transient non-community water system
(NTNCWS) means a public water system that is not a community water
system and that regularly serves at least 25 of the same persons over 6
months per year. Only a national representative sample of community and
non-transient non-community systems serving 10,000 or fewer persons
would be required to monitor. Transient non-community systems (i.e.,
systems that do not regularly serve at least 25 of the same persons
over six months per year) would not be required to monitor. States,
Territories, and Tribes, with primacy to administer the regulatory
program for public water systems under the Safe Drinking Water Act
sometimes conduct analyses to measure for contaminants in water samples
and are regulated by this action. Categories and entities potentially
regulated by this action include the following:
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Category Examples of potentially regulated entities SIC
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State, Territorial and Tribal Governments.. States, Territories, and Tribes that analyze water 9511
samples on behalf of public water systems required to
conduct such analysis; States, Territories, and
Tribes that themselves operate community and non-
transient non-community water systems required to
monitor.
Industry................................... Private operators of community and non-transient non- 4941
community water systems required to monitor.
Municipalities............................. Municipal operators of community and non-transient non- 9511
community water systems required to monitor.
----------------------------------------------------------------------------------------------------------------
This 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 of
that could potentially be regulated by this action. Other types of
entities not listed in the table could also be regulated. If you have
questions regarding the applicability of this action to a particular
entity, consult the person listed in the preceding FOR FURTHER
INFORMATION CONTACT section.
I. Statutory Authority
SDWA section 1445(a)(2), as amended in 1996, requires EPA to
establish criteria for a program to monitor unregulated contaminants
and to publish, by August 6, 1999, a list of contaminants to be
monitored. To meet these requirements, today's rule EPA substantially
revises the existing Unregulated Contaminant Monitoring (UCM) Program,
which is codified at 40 CFR 141.40. This final rule revises the
regulations at 40 CFR 9.1, 141.35, 141.40, 142.16 and deletes and
reserves 142.15(c)(3). The rule covers: (1) the frequency and schedule
for monitoring, based on PWS size, water source, and likelihood of
finding contaminants; (2) a new, shorter list of contaminants for which
systems will monitor; (3) procedures for selecting and monitoring a
nationally representative sample of small PWSs (those serving 10,000 or
fewer persons), and; (4) procedures for entering the monitoring data in
the National Drinking Water Contaminant Occurrence Data Base (NCOD), as
required under section 1445.
II. Major Program Revisions
Since its inception in 1988, the UCM Program has collected
occurrence data to help EPA determine which contaminants EPA should
regulate based on contaminant concentrations in PWSs and the
contaminants' adverse health effects levels. Today's rule is designed
to improve and enhance this program in several important ways:
(1) A statistical approach to select only 800 representative
systems for monitoring from the national total of 65,600 small systems
reduces the monitoring burden of the water supply industry; the burden
on small systems is significantly further reduced in that EPA will pay
for virtually all of the costs associated with monitoring for the small
systems that are part of the representative sample;
(2) A smaller number of contaminants to be monitored also reduces
the testing and reporting burden of the water industry overall;
(3) The required information to be reported about each contaminant
has been refined to improve the data quality for regulatory decisions;
and
(4) Direct reporting of data for regulatory determination and
development from systems to EPA reduces State reporting burden, and the
opportunity for electronic reporting reduces the potential for data
entry and submission.
A three-tier monitoring approach allows monitoring to start
promptly for contaminants with approved analytical methods, while
accommodating the need to delay implementation for contaminants needing
further methods development. The rule also allows use of a State-EPA
Memorandum of
[[Page 50559]]
Agreement, providing direct implementation in each State rather than
implementation through primacy revisions, to address the three-tiered
approach of the UCMR.
This program is a cornerstone of the ``sound science'' approach to
future drinking water regulations, which is a goal of the 1996 SDWA
Amendments. Data generated by this final rule will be used to: (1)
evaluate and prioritize contaminants on the Contaminant Candidate List
(CCL) and refine the CCL; (2) support the Administrator's determination
of whether to regulate a contaminant under the drinking water program;
and, (3) support the development of drinking water regulations.
In a related, cost-savings action, EPA published a Direct Final
Rule (64 FR 1494) on January 8, 1999, suspending the monitoring
requirements in effect for small systems serving 10,000 or fewer
persons. The third round of monitoring by small systems under the
existing list of unregulated contaminants would have overlapped with
the monitoring required under this final rule. The Direct Final Rule
saved small systems and States the cost of unnecessary monitoring. EPA
believes it obtained sufficient data from the previous monitoring
rounds to make decisions concerning the occurrence of the unregulated
contaminants on its prior monitoring list for these systems. Large
systems were not included in this Direct Final Rule since they had
already begun the third round of monitoring in January 1998. This large
system monitoring will provide confirming information on the occurrence
of those contaminants. However, this final regulation cancels further
monitoring by large systems for the existing list of contaminants
effective January 1, 2001. Until that date, large systems must continue
to monitor for the 48 contaminants listed in 40 CFR 141.40 (and also
listed in Table 1 of ``Revisions to the Unregulated Contaminant
Monitoring Regulation for Public Water Systems,'' Federal Register,
vol. 64, no. 83, April 30, 1999, p. 23401 (64 FR 23401)).
III. Regulatory Background
The requirements for unregulated contaminant monitoring were first
established by the 1986 SDWA Amendments. Under this law, EPA
implemented the drinking water standards in phases, with each phase
having a set of contaminants for which maximum contaminant levels in
drinking water were established. The phases also included unregulated
contaminants for which more information was needed before decisions
could be made regarding regulation of the contaminants. EPA included
unregulated contaminant monitoring requirements in the Phase I chemical
regulation, under 40 CFR 141.40(a)-(e). The Phase II regulation later
superceded the Phase I rule, and some of the Phase I unregulated
contaminants became regulated under Phase II. Additional contaminants
were also added to the list of unregulated contaminants. The Phase V
chemical regulation further modified the list of contaminants, as
additional unregulated contaminants became regulated.
The basic monitoring and reporting requirements for unregulated
contaminants were the same under the Phase I, Phase II, and Phase V
regulations. PWSs were required to report their monitoring results to
the primacy agencies (either the State or EPA), with States, in turn,
reporting to EPA. Only systems serving fewer than 150 service
connections were exempt from monitoring--provided they made their
facilities available for monitoring by the States. Repeat monitoring
was required every 5 years.
Section 125 of the 1996 SDWA Amendments substantially revised
unregulated contaminant monitoring program. The new program includes:
(1) a new list of contaminants (i.e., the Unregulated Contaminant
Monitoring Regulation (UCMR) (1999) List; (2) a representative sample
of PWSs serving 10,000 or fewer persons to monitor; (3) placement of
the monitoring data in the NCOD, and; (4) notification of consumers
that the monitoring results are available.
The 1996 amendments limit the number of contaminants to be
monitored on the UCMR list to a maximum of 30. The amendments specify
that only a representative sample of small systems are required to
monitor, and that EPA must pay the reasonable costs of analyzing the
samples taken by those systems. EPA will use the data generated by this
monitoring effort in the development of future drinking water
regulations.
Today's final rule will completely replace the requirements of the
existing rule on the final rule's effective date of January 1, 2001.
The existing requirements of 40 CFR 141.35 and 141.40 still apply to
large systems serving more than 10,000 persons, (since their third
round of monitoring had begun in January 1998) until January 1, 2001,
as noted above in II. Major Program Revisions.
IV. Process of Preparing the Final Rule
EPA has been developing the final revisions to the Unregulated
Contaminant Monitoring Regulation (UCMR) for public water systems since
1997. In December, 1997, EPA's UCMR development workgroup held a
stakeholders meeting to obtain input from the public on major issues
and options affecting the program and emanating from the Safe Drinking
Water Act, as amended in 1996. EPA held a second stakeholders meeting
in May 1998, on options under serious consideration for the UCMR. EPA
engaged eleven external expert reviewers from March 1 through April 22,
1999 to examine and comment on the technical aspects of the proposed
rule. These technical reviewers evaluated and commented on the chemical
and microbiological contaminant analytical methods and reporting
requirements, the statistical approach for the representative sample of
small systems, and the sampling and monitoring approach. The comments
of the technical reviewers were available to the public through the
official docket and on the Internet through EPA's Office of Ground
Water and Drinking Water electronic homepage.
EPA published the proposed rule in the Federal Register on April
30, 1999, for public comment. The comment period closed on June 14,
with submissions from 39 commenters meeting the deadline and addressing
all major aspects of the proposed regulation. EPA received one hundred
sixteen comments after the public comment period closed, principally
concerning the inclusion of perchlorate on the UCMR monitoring list.
EPA considered and addressed all comments in the process of developing
this final regulation.
V. Concise Description of Today's Action
A. Which Systems Must Monitor
Owners and operators of community and non-transient noncommunity
water systems must monitor for unregulated contaminants if they serve
more than 10,000 persons or if they are part of the representative
sample of small systems serving 10,000 or fewer persons that will be
randomly selected to monitor for these contaminants. Transient systems
are not required to monitor for unregulated contaminants. Only
purchased water systems that are identified by EPA or the State to
sample at locations of low disinfectant residual or longest residence
time are required to monitor for distribution system contaminants.
[[Page 50560]]
B. System Monitoring Requirements
The contaminants included in this action are: 2,4-dinitrotoluene,
2,6-dinitrotoluene, DCPA mono acid degradate, DCPA di acid degradate,
4,4'-DDE, EPTC, molinate, MTBE, nitrobenzene, terbacil, acetochlor, and
perchlorate. Systems must also analyze for water quality parameters
including, for chemical contaminants: pH; and for microbiological
contaminants: pH, temperature, turbidity, free disinfectant residual
and total disinfectant residual. Surface water systems must monitor
during four consecutive quarters. Ground water systems must monitor two
times five to seven months apart. One sampling event for surface and
ground water systems must be during the vulnerable time of May 1 to
July 31, or during an alternate vulnerable time selected by the State.
Monitoring must be conducted at the entry point to the distribution
system, or at other sampling locations previously specified by the
State for compliance monitoring, for sampling points representative of
each principal, non-emergency water source in use over the one year of
monitoring. Large and small systems must monitor according to the
quality control procedures described. Laboratories that are certified
to use the indicated methods for the contaminants listed are
automatically certified to analyze for unregulated contaminants. Small
systems that are part of the representative sample which become part of
State Monitoring Plans must follow instructions given them for
unregulated contaminant sampling and shipment to the designated
laboratory.
C. System Reporting Requirements
After testing for the contaminants on the monitoring list, the
systems must report the results electronically to, or in an alternate
format previously arranged with, EPA within 30 days following the month
they receive the results. EPA will report the results for the small
systems that are selected to be part of the State Monitoring Plans. EPA
will hold the data for 60 days to allow for quality control review by
systems and States before placing the data in the National Drinking
Water Contaminant Occurrence Database.
Data required to be reported include: Public Water System (PWS)
Identification Number; Sample Identification Number; Sample Collection
Date; Contaminant/Parameter; Analytical Results--Sign; Analytical
Result--Value; Analytical Result--Unit of Measure; Analytical Method
Number; Public Water System Facility Identification Number--Source,
Treatment Plant and Sampling Point; Sample Analysis Type; Detection
Level; Detection Level Unit of Measure; Batch Identification Number;
Spiking Concentration; Analytical Precision; Analytical Accuracy;
Presence/Absence.
A system can have a laboratory report the results for it, but the
system retains the responsibility for reporting. A system can report
previously collected data as long as the data meet the requirements
specified in 40 CFR 141.40(a) (3), (4), (5) and Appendix A and include
the applicable water quality parameters and data listed previously that
are required to be reported.
D. State and Tribal Participation
States and Tribes can enter into a Memorandum of Agreement (MOA)
with the EPA concerning the implementation of the monitoring program.
The MOA must address the following: accepting or modifying the State
Monitoring Plan for small systems, determining an alternate vulnerable
time, modifying the timing of monitoring, identifying sampling points
for small systems, notifying small and large systems of their
monitoring responsibilities, and providing instructions to systems. A
State can remove a system from the State Monitoring Plan, after EPA
review, as long as removal is not based on prior information on the
occurrence or non-occurrence of contaminants at the system or the
vulnerability of the system to the contaminants. States can decide not
to participate in an MOA, in which case the EPA will establish a State
Monitoring Plan. The governors of seven or more States can petition EPA
to add contaminants to the monitoring list. States can apply to EPA to
waive monitoring for large systems if they can demonstrate that the
contaminants for which a monitoring waiver is sought have not occurred
in the State in the past 15 years.
VI. Final Changes in the Unregulated Contaminant Monitoring Program
A. Revised List of Unregulated Contaminants To Be Monitored
1. Criteria for Selecting Contaminants for the UCMR
(a) Revising the UCMR (1999) List
Section 1445(a)(2)(B) requires EPA to list not more than 30
unregulated contaminants to be monitored by public water systems. EPA
used the 1998 Contaminant Candidate List (CCL), established under
section 1412(b)(1)(B) of SDWA, as the primary basis for selecting
contaminants for future monitoring under the UCMR. Development of the
CCL is discussed in the preamble to the proposed rule at 64 FR 23402.
EPA believes, and nearly all public commenters addressing the use of
the CCL as the basis for the UCMR List indicated, that the CCL process
already uses the best available information on contaminants of concern
and emerging contaminants that may need regulation. SDWA section 1445
(a)(2)(B)(ii) provides for the governors of seven or more States to
petition the Agency to add contaminants to the UCMR List. This petition
process allows for the flexibility to include contaminants that are
emerging as concerns between the five-year listing cycles.
The CCL lists 26 chemical and 8 microbiological contaminants as
occurrence priorities because additional data on their occurrence in
drinking water are needed to help decide whether they should be
regulated. The proposed rule did not address the two contaminants
identified in the preparation of the CCL as highly localized in
occurrence: perchlorate and RDX (hexahydro-1,3,5-trinitro-1,3,5-
triazine). EPA now has information indicating that the occurrence of
these contaminants is more widespread than originally thought. In
response to this information, some of which was provided in public
comments, EPA has added perchlorate and RDX to the final UCMR (1999)
List. Perchlorate was added to the UCMR (1999) List because EPA feels
that there is enough information on its occurrence in public water
systems to warrant its inclusion in a national monitoring program.
Since it was not included on the proposed UCMR (1999) List, EPA did not
take comment on its analytical method, minimum reporting level, or
sampling location. EPA is currently engaged in final validation of an
analytical method for perchlorate. This validation is important because
earlier analytical methods did not make adjustments for interferences
from sulfate and chloride, thus reducing or eliminating detected
concentrations. EPA feels that with this validation, the analytical
method should be sufficiently ready for monitoring, and thus EPA has
included perchlorate on the UCMR List 1. EPA plans to publish, for
public comment, the analytical method, minimum reporting level, and
sampling location for perchlorate shortly after the promulgation of
this final rule. RDX now appears on UCMR (1999) List 2, indicating that
additional information is available, and initial monitoring of
occurrence in public water systems should occur but that its method
needs further refinement.
[[Page 50561]]
Additionally, based on technical peer review and public comments,
EPA moved Aeromonas from UCMR (1999) List 1 to UCMR (1999) List 2 in
Table 1, because its analytical method is not expected to be validated
until 2000 or 2001. Also, in response to public comments that the
Agency include as many contaminants that could be tested under the same
multi-analyte method as possible in Assessment Monitoring, EPA moved
acetochlor to List 1 from List 2. This action is based on information
that only minor refinements are needed in the method and those can be
resolved before the effective date of today's rule. As a result, the
analytical method is reserved until the details of the method are
resolved. EPA plans to publish a revision to this final rule to approve
an analytical method for acetochlor shortly after this rule's
promulgation. EPA will likely publish a joint request for public
comment on the analytical methods for perchlorate and acetochlor. EPA
intends to approve and publish the methods as early as possible to
allow monitoring to begin on January 1, 2001, and to allow for the
reporting of any data obtained prior to January 1, 2001 to meet the
requirements of this final Rule.
For the remaining contaminants on the CCL Occurrence Priorities
List, EPA has evaluated the availability of analytical methods
published by EPA or voluntary consensus standards organizations, such
as the American Society for Testing and Materials (ASTM) and Standard
Methods (SM). In addition, EPA prioritized analytical methods
development activities for those compounds and microorganisms for which
suitable analytical methods are not currently available. As listed in
List 1 of Table 1, EPA identified 10 of the 12 listed chemical
contaminants for which analytical methods are now available. UCMR
(1999) List 1 contaminants are those for which monitoring is required
under today's Rule, with the added note that analytical methods have
yet to be approved for perchlorate and acetochlor. UCMR (1999) List 2
of Table 1 lists 16 contaminants for which analytical methods are being
refined: 14 chemical contaminants, Aeromonas (a microorganism), and
polonium-210 (discussed in Table 1). UCMR (1999) List 3 of Table 1
identifies seven microbiological contaminants and lead-210 for which
analytical methods are being researched. Monitoring for contaminants on
UCMR (1999) Lists 2 and 3 is not required until EPA promulgates
revisions to this rule to specify analytical methods and related
sampling requirements for them.
EPA requested comment on the addition to the UCMR (1999) List of
two naturally occurring radionuclides with health concerns at low
levels, lead-210 (pb-210), and polonium-210 (po-210). Both nuclides are
in the uranium decay series, which also includes radium-226 and radon-
222. Lead-210, with a half-life of 22 years, and one of its degradates,
polonium-210, with a half-life of 138 days, have been found in drinking
water. EPA is aware of the occurrence of these contaminants in shallow
aquifers in Florida (Harada, et al., 1989; Upchurch, 1991), and in at
least two other States. Because of potential occurrence, consequent
health risks, and in response to public comments, EPA has added
polonium-210 and lead-210 to the UCMR (1999) List and has placed them
on Lists 2 and 3 respectively.
(b) Regulatory Approach for the UCMR (1999) List
EPA establishes in Sec. 141.40(a)(3) that the contaminants listed
in Lists 1-3 comprise the UCMR (1999) List, categorized based on the
availability of analytical methods. UCMR (1999) List 1 is the basis for
Assessment Monitoring. Assessment Monitoring will occur at all 2,774
large community and non-transient non-community public water systems
serving more than 10,000 persons and at a representative sample of
approximately 800 systems serving 10,000 or fewer persons identified in
State Monitoring Plans. UCMR (1999) List 2 will be the basis for two
Screening Surveys of approximately 300 systems each, statistically
selected from those systems required to conduct Assessment Monitoring.
UCMR (1999) List 3 will be used for Pre-Screen Testing at up to 200
systems selected because of their potential vulnerability to the
specific contaminants. This monitoring approach is described in detail
under Section VI.C, ``Type of Monitoring Required of Public Water
Systems Based on Listing Group.'' Assessment Monitoring (and associated
``Index system'' monitoring) is the only monitoring that would be
required by today's action. This includes contaminants for which EPA
expects to have developed analytical methods before implementation:
perchlorate and acetochlor.
For contaminants on UCMR (1999) List 2 for which analytical methods
are developed by the time of initial monitoring in 2001, EPA will amend
this rule to require the first Screening Survey to be conducted at
selected systems. For those contaminants on List 2 and List 3 that do
not have well developed methods by the time of initial monitoring in
2001, EPA will issue a revision to this regulation to activate
monitoring for them at the time when the methods are considered
implementable, up to the limit of 30 contaminants to be monitored
within the five-year contaminant listing cycle. Monitoring for those
contaminants will then begin at a date specified in that prospective
regulation. Therefore, monitoring of contaminants on UCMR (1999) Lists
2 and 3 is not required by today's action. Monitoring of these
contaminants will only occur when EPA publishes a revision to this
regulation specifying the analytical methods to be used and the period
during which monitoring is to be completed.
(c) Analytical Methods Applicable to the UCMR (1999) List
The UCMR (1999) List development process focuses primarily on the
availability of analytical methods for the listed contaminants and the
level of information available for them at the time of its development.
The discussion below highlights analytical method considerations in
listing the contaminants for monitoring. Only the contaminants
identified on UCMR (1999) List 1, will be monitored as a result of
today's action, with the exceptions of perchlorate and acetochlor, for
which analytical methods have yet to be approved. Contaminants on UCMR
(1999) Lists 2 and 3 are included on the final UCMR (1999) List, but
will not be activated for monitoring until EPA proposes and promulgates
analytical methods that can be used to reliably measure their
occurrence in drinking water. At that time, EPA will propose
regulations for the monitoring of UCMR (1999) List 2 and 3
contaminants.
(i) Chemical Analytical Methods
The ability to correctly identify a chemical contaminant is
directly related to the type of chemical and the analytical method
used. Compounds such as disinfection byproducts are far less likely to
be misidentified than pesticides because they are typically present at
relatively high concentrations in disinfected waters, while pesticides
are much less likely to occur, or occur at lower concentrations. The
analytical method selected will determine the accuracy of the
qualitative identification. In general, the most reliable qualitative
identifications will come from methods that use mass spectral data for
contaminant identification. However, these methods are typically less
sensitive than methods that rely on less selective detectors.
[[Page 50562]]
Before EPA establishes a Maximum Contaminant Level (MCL), the
Agency relies on an analytical method suitable for routine monitoring.
It is likely that analytical methods in general use by laboratories
performing drinking water analyses may not exist for some of the final
compounds to be measured in the UCMR program. Complex analytical
methods or methods requiring special handling often require more
experienced laboratories than the laboratories performing routine
compliance monitoring. Even when analytical methods that are in general
use by analytical laboratories are available, limiting the analyses to
a small number of laboratories operating under strict quality control
requirements improves the precision and accuracy of the analyses,
thereby increasing the usefulness of the data.
The option favored by many stakeholders for conducting the chemical
laboratory analyses and made final today by EPA is the following:
For PWSs serving more than 10,000 people, the PWS is responsible
for sample collection and analyses for Assessment Monitoring. This
monitoring may be conducted at the same time as the required compliance
monitoring, to the extent possible. For Assessment Monitoring, however,
EPA requires in Sec. 141.40(a)(3) and Sec. 141.40 Appendix A, quality
control procedures for both sampling and testing to ensure that the
data collected under this regulation are of sufficient quality to meet
the requirements of the related regulatory decisions. Thus, today's
action specifies the analytical methods and procedures to be used in
obtaining these data. The sampling and associated quality control
requirements cover time frame, frequency, sample collection and
submission, and review and reporting of results. The laboratory
analytical quality control requirements address the use of a certified
laboratory, sample collection/preservation, analytical methods, method
detection limits, calibration, quality control samples, method
performance tests, detection confirmation, and reporting. PWSs serving
10,000 or fewer persons must send their Assessment Monitoring samples
to laboratories designated by EPA, since the Agency must pay for the
reasonable costs of testing.
The purpose of the quality control requirements is to ensure that,
since EPA will only be able to obtain results from 3,574 systems (2,774
large systems and a representative sample of 800 systems from 65,600
systems serving 10,000 or fewer persons), the Agency obtains the most
reliable data possible. EPA is specifying the use of certain analytical
methods that are currently available for monitoring (see Table 3, UCMR
(1999) List, column 3). While these methods are routinely used by
commercial and public water system laboratories (including some that
are currently used for compliance monitoring), they have not been
routinely used for the contaminants on the UCMR (1999) List. Note that,
as shown in Sec. 141.40(a)(3), Table 1, methods other than those that
EPA has developed may be approved for use, but quality control
procedures must also be followed, as specified in Sec. 141.40(a)(3),
(4) and (5), and Appendix A.
For the compounds included in this regulation, the following
summary, Table 1, Status of Analytical Methods for Chemical
Contaminants on the UCMR (1999) List, presents a brief overview of
methods availability for each chemical contaminant.
Table 1.--Status of Analytical Methods for Chemical Contaminants on the UCMR (1999) List
----------------------------------------------------------------------------------------------------------------
CAS No. Analytical methods Status of availability
----------------------------------------------------------------------------------------------------------------
UCMR (1999) List 1--Chemical Contaminant
----------------------------------------------------------------------------------------------------------------
2,4-dinitrotoluene............ 121-14-2 EPA 525.2............ Method is adequate for monitoring.
2,6-dinitrotoluene............ 606-20-2 EPA 525.2............ Method is adequate for monitoring.
4,4'-DDE...................... 72-55-9 EPA 508.............. Methods are adequate for monitoring.
EPA 508.1............
EPA 525.2............
D5812-96.............
AOAC 990.06..........
Acetochlor.................... 34256-82-1 In validation process EPA anticipates that this compound can be
added to the scope of EPA Method 525.2.
DCPA di acid degradate........ 2136-79-0 EPA 515.1............ No method is available to measure the
EPA 515.2............ mono and di acid forms separately. All
D5317-93............. of the approved methods identify total
AOAC 992.32.......... mono and di acid forms.
DCPA mono acid degradate...... 887-54-7 EPA 515.1............ No method is available to measure the
EPA 515.2............ mono and di acid forms separately. All
D5317-93............. of the approved methods identify total
AOAC 992.32.......... mono and di acid forms.
EPTC.......................... 759-94-4 EPA 507.............. Methods are adequate for monitoring.
EPA 525.2............
D5475-93.............
AOAC 991.07..........
Molinate...................... 2212-67-1 EPA 507.............. Methods are adequate for monitoring.
EPA 525.2............
D5475-93.............
AOAC 991.07..........
MTBE.......................... 1634-04-4 EPA 524.2............ Methods are adequate for monitoring.
D5790-95.............
SM6210D..............
SM6200B..............
Nitrobenzene.................. 98-95-3 EPA 524.2............ Methods are adequate for monitoring.
D5790-95.............
SM6210D..............
SM6200B..............
[[Page 50563]]
Perchlorate................... 14797-73-0 In validation process EPA is currently conducting analytical
methods development to support the
analyses of perchlorate. This new method
will be based on the currently available
ion chromatography methods, but will
include a criteria detailing when a
laboratory must perform a sample clean-
up procedure to minimize the impact of
elevated concentrations of chloride,
sulfate or other dissolved solids.
Terbacil...................... 5902-51-2 EPA 507.............. Methods are adequate for monitoring.
EPA 525.2............
D5475-93.............
AOAC 991.07..........
UCMR (1999) List 2--Chemical
Contaminant
1,2-diphenylhydrazine......... 122-66-7 In development....... Some methods evaluated but inadequate for
monitoring. Priority for analytical
method development. EPA anticipates that
contaminant will be added to the scope
of EPA Method 525.2.
2,4,6-trichlorophenol......... 88-06-2 In development....... EPA Method 552 evaluated but subject to
false positives from interferences of
the derivitized byproduct of the
contaminant. EPA anticipates that
contaminant will be included in a new
SPE/GC/MS method currently under
development.
2,4-dichlorophenol............ 120-83-2 In development....... EPA Method 552 evaluated but subject to
quantitative uncertainty due to
inadequate derivatization of the
contaminant. EPA anticipates that
contaminant will be included in a new
SPE/GC/MS method currently under
development.
2,4-dinitrophenol............. 51-28-5 In development....... Some methods evaluated but inadequate for
monitoring. EPA anticipates that
contaminant will be included in a new
SPE/GC/MS method currently under
development.
2-methylphenol................ 95-48-7 In development....... Some methods evaluated but inadequate for
monitoring. EPA anticipates that
contaminant will be included in a new
SPE/GC/MS method currently under
development.
Alachlor ESA and degradation .............. To be determined..... EPA is evaluating which specific
byproducts of acetanilide contaminants will be included within
pesticides. this group of compounds. Analytical
methods will be determined for the
targeted contaminants.
Diazinon...................... 333-41-5 In development....... Diazinon is listed as a contaminant in
several EPA and voluntary consensus
standard organization methods but it is
subject to rapid aqueous degradation.
Preservation research currently being
conducted to develop a preservation
technique that would permit adding this
compound to EPA Method 525.2.
Disulfoton.................... 298-04-4 In development....... Disulfoton is listed as a contaminant in
several EPA and voluntary consensus
standard organization methods but it is
subject to rapid aqueous degradation.
Preservation research currently being
conducted to develop a preservation
technique that would permit adding this
compound to EPA Method 525.2.
Diuron........................ 330-54-1 In development....... While this compound is included in the
scope of NPS Method 4 (LLE/HLPC/UV) and
EPA Method 553 (SPE/HPLC/MS), these
methods are not adequate for this
monitoring. EPA anticipates that this
compound can be included in a new SPE/
HPLC/UV method currently being
developed.
Fonofos....................... 944-22-9 In development....... Fonofos is listed as a contaminant in
several EPA and voluntary consensus
standard organization methods but it is
subject to rapid aqueous degradation.
Preservation research is currently being
conducted to develop a preservation
technique that would permit adding this
compound to EPA Method 525.2.
Linuron....................... 330-55-2 In development....... While this compound is included in the
scope of NPS Method 4 (LLE/HLPC/UV) and
EPA Method 553 (SPE/HPLC/MS), these
methods are not adequate for this
monitoring. EPA anticipates that this
compound can be included in a new SPE/
HPLC/UV method currently being
developed.
Polonium-210 (<SUP>210</SUP>Po).......... 13981-52-7 In development....... Radiochemistry laboratory capacity is
limited.
[[Page 50564]]
Prometon...................... 1610-18-0 In development....... Prometon is listed as a contaminant in
several EPA and voluntary consensus
standard organization methods but it is
subject to rapid aqueous degradation in
non-acidified samples and is not readily
extracted in acidified samples.
Preservation research is currently being
conducted to add neutralizing the pH of
acidified samples just prior to
extraction. This would permit adding
this compound to EPA Method 525.2.
RDX........................... 121-82-4 In development....... No EPA or consensus methods organization
analytical methods for the analysis of
RDX in water are currently available.
Terbufos...................... 13071-79-9 In development....... Terbufos is listed as a contaminant in
several EPA and voluntary consensus
standard organization methods but it is
subject to rapid aqueous degradation.
Preservation research is currently being
conducted to develop a preservation
technique that would permit adding this
compound to EPA Method 525.2.
UCMR (1999) List 3--Chemical
Contaminant
Lead-210 (<SUP>210</SUP>Pb).............. 14255-04-0 In development....... Method is time-consuming and expensive.
Radiochemistry laboratory capacity is
limited.
----------------------------------------------------------------------------------------------------------------
(ii) Microbiological Analytical Methods
The discussion of data quality for chemical analytical methods also
applies to microbiological testing when analytical methods are
developed for CCL microorganisms. When microorganisms were proposed for
the CCL, EPA recognized that analytical methods were not well developed
for the majority of them. Because of the lack of available analytical
methods, some of the CCL microorganisms were grouped either into one
category where information was available about methodologies indicating
a need to further refine them, or another category where more research,
including research on detection methods and occurrence, was needed. At
the present time, and based on technical peer review and public
comment, Aeromonas is the only one of the microorganisms for which more
occurrence data are needed that also has an analytical method likely to
be sufficiently developed for monitoring in time for implementation of
the Screening Surveys. Three other microorganisms have methods
available, but are in need of further methods development. These
microorganisms (Cyanobacteria, Echoviruses, and Coxsackieviruses) may
be candidates for the Screening Surveys if methods development proceeds
expeditiously (Sec. 141.40(a)(3), Table 1, List 2), but are currently
identified for Pre-Screen Testing (Table 1, List 3). The remaining four
microorganisms currently lack satisfactory methods and will be
evaluated for Pre-Screen Testing.
Several microorganisms on the CCL are actually groups of
microorganism taxa. In some cases, the taxa have so many members that,
given the limited resources available for UCMR monitoring, EPA may have
to prioritize which strains, species, or serotypes are the most
important to consider and target those for monitoring or further study.
Decisions will have to be made on the basis of health risk,
disinfection resistance, occurrence in water, and other factors. To
address the need to prioritize which microorganisms should be targeted
for monitoring, EPA's Office of Research and Development is assisting
the Office of Ground Water and Drinking Water in establishing a
research program for health effects, treatment, and analytical methods.
Table 2.--Status of Analytical Methods for Microbiological Contaminants on the UCMR (1999) List
----------------------------------------------------------------------------------------------------------------
Availability of analytical
method Status of availability
----------------------------------------------------------------------------------------------------------------
List 2--Microbiological Contaminant
Aeromonas.......................... Analytical method likely to Current modification and evaluation of a
be available for published membrane filtration method
monitoring. (Havelaar et al., 1987) indicates that this
method will be suitable for the monitoring
program.
List 3--Microbiological Contaminant
Cyanobacteria (blue-green algae, Methods available but not Methods are available for counting
other freshwater algae and their standardized. cyanobacteria but new, standardized methods
toxins). are needed for direct counts of targeted
species with filtration methods or a counting
chamber. Standardized analytical methods are
also needed to detect the more important
cyanobacterial toxins.
Echoviruses........................ Methods available but not Echoviruses can be cultured on BGM cells and
standardized. detected by the ICR method but require
supplemental methods such as serological
typing to distinguish echoviruses from other
viruses. Cost of cell culture assays plus
serotyping can be high. RT/PCR methods are
subject to interferences and do not
demonstrate infectivity. Combined cell
culture and PCR, which demonstrates
infectivity, may be considered.
[[Page 50565]]
Coxsackieviruses................... Methods available but not Group B coxsackieviruses are easy to grow in
standardized. tissue culture but group A coxsackievirus
detection in cell culture is variable.
Culturable coxsackieviruses can be detected
with the ICR method but serological typing is
needed to distinguish coxsackieviruses from
other viruses. RT/PCR methods are subject to
interferences and do not demonstrate
infectivity. New, standardized methods are
needed. Combined cell culture and PCR methods
may be considered.
Helicobacter pylori................ No suitable method Helicobacter pylori is difficult to cultivate
currently available. because of its slow growth rate and the need
for a low oxygen environment. No selective
medium exists that will discriminate H.
pylori from background bacteria. A culture-
based method that demonstrates viability is
preferred. Methods are needed for selective
growth and identification. IMS has been used
to concentrate Helicobacter pylori. Methods
using PCR alone have been used but have not
been validated by EPA. In general, PCR
methods are not preferred due to
interferences and their inability to
demonstrate viability. A combined cultural
and molecular method may be considered.
Microsporidia...................... No suitable method No methods are available for the monitoring of
currently available. the two species of human microsporidia which
may have a waterborne route of transmission
[Enterocytozoon bienuesi and Encephalitozoon
(formerly Septata) intestinalis]. Spores
could possibly be detected by methods similar
to those being developed for Cryptosporidium
parvum. Potential methods may utilize water
filtration, clean-up with IMS, and detection
using microscopy with either fluorescent
antibody or gene probe procedures. Provided
that procedures are validated by EPA, reverse-
transcriptase (RT)--PCR techniques may be
considered for monitoring, although PCR
methods in general are not preferred at this
time due to interferences and their inability
to demonstrate viability. Due to the small
size of microsporidia, problems could be
encountered during filtration.
Adenoviruses....................... No suitable method Adenoviruses serotypes 1 to 39 and 42 to 47
currently available. can be grown in tissue culture but enteric
adenoviruses 40 to 41 are difficult to grow.
Several selective tissue culture methods and
detection methods have been reported. A
selective, standardized method is needed for
monitoring. PCR methods are not preferred, as
they are subject to interferences and do not
demonstrate infectivity. A combined cell
culture and PCR method may be considered.
Caliciviruses...................... No suitable method No tissue culture methods exist for the two
currently available. genogroups of caliciviruses on the CCL (the
Norwalk-like and the Snow Mountain-like
agents). No sensitive or fully developed
detection methods exist. PCR methods are not
preferred, as they are subject to
interferences and do not demonstrate
infectivity. A combined cell culture and PCR
method may be considered if a suitable cell
line is found.
----------------------------------------------------------------------------------------------------------------
2. List of Contaminants To Be Monitored
(a) Final UCMR (1999) List
Section 141.40 (a)(3) Table 1, Unregulated Contaminant Monitoring
Regulation (1999) List, presents EPA's list of unregulated contaminants
for monitoring under Section 1445(a)(2)(B)(i) of the 1996 Amendments
for the first five-year listing cycle. The monitoring program for these
contaminants is a three-tiered approach based on the availability of
information about each contaminant and the availability of analytical
methods for each contaminant. This approach is described in Section C.,
Type of Monitoring Required of Public Water Systems Based on Listing
Group. The final monitoring program divides the listed unregulated
contaminants into three lists: List 1, for which Assessment Monitoring
will be required, List 2, designated for the Screening Surveys; and
List 3, designated for Pre-Screen Testing. Today's final regulation
only requires Assessment Monitoring for UCMR (1999) List 1 contaminants
beginning on January 1, 2001, with the exceptions of perchlorate and
acetochlor, for which analytical methods have not yet been approved
(but are planned to have monitoring begin on that date, also, after
rulemaking to specify their analytical methods). The monitoring for
contaminants on Lists 2 and 3 will only be required after EPA
promulgates further rules.
Technical peer review and public comments strongly supported the
three-tier approach of the UCMR program. As a result, EPA requires in
today's action Assessment Monitoring for the contaminants on UCMR
(1999) List 1, because analytical methods for these contaminants
currently exist or will shortly be validated. EPA will shortly publish
a request for public comment on a revision to this final rule to
implement the analytical methods and other sampling requirements for
perchlorate and acetochlor. Also, by future rulemaking, EPA plans to
implement the Screening Survey (List 2) monitoring in groups of
contaminants, rather than one contaminant at a time, to minimize
sampling and testing costs since some of the contaminants may be tested
by the
[[Page 50566]]
same method. EPA intends to take a similar approach with the
contaminants on List 3, the Pre-Screen Testing. EPA plans to require,
through future rulemaking, Pre-Screen Testing for contaminants for
which EPA determines that new analytical methods can measure their
existence in locations where they are most likely to be found. All
analytical methods for contaminants on Lists 2 and 3 would be peer
reviewed, following EPA's policy for peer review, before the Agency
proposes regulations which would require public water systems to
monitor for them.
In Sec. 141.40 (a)(3), Table 1, UCMR (1999) List 1 contaminants,
for Assessment Monitoring, are chemical contaminants for which
analytical methods capable of generating the quantity and quality of
data required under the UCMR are currently available, or expected to be
available shortly after today's final rule. Monitoring for these
contaminants is required under today's final UCMR, with the exceptions
of perchlorate and acetochlor, as noted.
UCMR (1999) List 2 contaminants (14 organic chemicals, one
radiochemical and one microorganism), for the Screening Surveys, are
those for which EPA is currently refining analytical methods.
Development of these methods should be sufficient for Screening Surveys
to be conducted in the first three years of the listing cycle, but may
occur in the later years of the cycle. These contaminants are
characterized in today's final rule at Sec. 141.40(a)(3), Table 1,
Unregulated Contaminant Monitoring Regulation (1999) List, List 2.
UCMR (1999) List 3 contaminants (seven microbiological contaminants
or contaminant groups and one inorganic chemical), for Pre-Screen
Testing, are those for which EPA has begun or shortly will begin
analytical methods development, but completion of those efforts is not
expected prior to the Assessment Monitoring required under
implementation of this regulation. Instead, these contaminants will be
tested for in Pre-Screen Testing. These contaminants are listed in
today's final rule at Sec. 141.40(a)(3) as Table 1, Unregulated
Contaminant Monitoring List, List 3.
Tables 3 and 4, in IV.A.1.(c), Analytical Methods Applicable to the
UCMR (1999) List, present a summary of the status of the methods for
all the contaminants on this list.
EPA believes that this three-tiered approach to the UCMR, which was
recommended by stakeholders, reflects a balance between the
implementability of current analytical methods and the need to obtain
data in time frames that are useful for responding to concerns about
the contaminants identified.
(b) Number of Contaminants on the UCMR (1999) List
Thirty-six contaminants are on today's final UCMR (1999) List. SDWA
Section 1445 (a)(2)(B)(i) states that in August 1999 and every five
years thereafter ``the Administrator shall issue a list of * * * not
more than 30 unregulated contaminants to be monitored by public water
systems and to be included in the national drinking water occurrence
data base * * *'' EPA interprets this to mean that the UCMR list may
contain more than 30 contaminants, as long as monitoring is not
required for more than 30 contaminants during a five-year listing
cycle. Public comments were split on whether the monitoring list should
have more than 30 contaminants. EPA believes that maintaining a
monitoring list with more than 30 contaminants, while requiring
monitoring for no more than 30, is responsive to public concerns about
contaminants in drinking water. This interpretation and approach also
supports EPA's efforts to respond to and encourage analytical methods
development for emerging contaminants.
Any PWS may voluntarily submit data to EPA, including data for
contaminants that a PWS may monitor that are on the UCMR (1999) List of
36 contaminants, but that are not on the final list of 30 contaminants
actually required for UCMR monitoring. EPA is preparing a guidance
document specifying the procedures for future voluntary submission of
such data to the National Drinking Water Contaminant Occurrence
Database (NCOD).
B. Public Water Systems Subject to the UCMR
The monitoring in this final rule focuses ultimately on
determination of, on a national basis, the occurrence or likely
occurrence of contaminants in drinking water delivered by community
water systems (CWS) and non-transient non-community water systems
(NTNCWS). For regulatory purposes, public water systems are categorized
as ``community water systems,'' or ``non-community water systems.''
Community water systems (CWSs) are specifically defined as ``public
water systems which serve at least 15 service connections used by year-
round residents or regularly serve at least 25 year-round residents.''
(40 CFR 141.2) A ``non-community water system'' means any other public
water system. Non-community water systems include nontranisent non-
community water systems (NTNCWSs) and transient non-community water
systems. Non-community water systems are available to serve the public,
but are not used on a year-round basis in most cases. Non-transient
systems regularly serve at least 25 of the same persons over six months
per year (e.g., schools). Transient systems do not regularly serve at
least 25 of the same persons over six months per year. Additionally,
some community water systems purchase all or part of their water supply
from other water systems. Purchased water systems may be at the end of
a distribution system from the water system selling the water.
One of the factors considered in establishing the UCMR program is
the number of persons served by a system. With respect to size, about
2,774 large systems (each serving more than 10,000 persons) provide
drinking water to about 80 percent of the U.S. population served by
public water systems. Under today's final regulation, all large systems
will be required to monitor the unregulated contaminants specified in
Sec. 141.40(a)(3), List 1 of Table 1, UCMR (1999) List, with the
exception of perchlorate and acetochlor for which analytical methods
have not been promulgated. In response to public comment on purchased
water systems representing the end of a distribution system, purchased
water systems are also included in this monitoring requirement for
microbiological contaminants that occur primarily in distribution
systems with maximum residence times or low disinfectant residuals
which may allow microorganisms that have human health effects to
survive and reproduce.
Section 1445(a)(2)(A) requires that the UCMR ensure that only a
representative sample of systems serving 10,000 or fewer persons (small
systems) monitor for unregulated contaminants. Small community water
systems and small non-transient, non-community water systems total
65,636 systems. From this total number of small systems, EPA will
select a national representative sample of 800 small systems. EPA is
excluding transient non-community systems from UCMR requirements. The
variation in the 97,000 transient systems would be difficult to reflect
in a national representative sample and would be very costly to
monitor. Furthermore, projecting contaminant exposure results from such
systems would be complex and inconclusive because of the transient
nature of the population that uses them. The results from the very
small community and non-transient non-community systems (NTNCWS) can be
extrapolated to the transient non-community systems. Public comments
[[Page 50567]]
supported not including these systems in the representative sample. One
commenter suggested that transient systems be the subject of a special
survey since they may be a pathway of exposure for a specific segment
of the population. At this time, EPA is not planning any special
surveys of transient systems because they are such a large and diffuse
category and it is difficult to compile and evaluate population
exposure information for this category of water systems.
EPA will pay for the reasonable costs of monitoring by the small
systems selected for the representative sample, as long as the systems
are part of a State Monitoring Plan. The EPA will select systems to
monitor through the use of a random number generator according to a
national representative sample selection plan developed primarily on
the basis of population served by PWSs in each State. This detailed
selection plan is necessary to ensure that the sample is statistically
valid and representative of all small water systems nationally. This
plan is also necessary because EPA typically has the least information
about these systems and needs a consistent base of data for regulation
development. EPA will use a national sample of approximately 800
systems serving 10,000 or fewer persons which the EPA will
statistically draw from all small CWSs and NTNCWSs nationally. Section
F, ``Representative Sample of Systems Serving 10,000 or Fewer
Persons,'' provides the details of the sample selection plan, including
the sample size. The number of systems selected within each size
category of systems will be based on the proportion of population
served by that size category. System selection will be further
allocated across water source type and distributed across all states.
The State-based component of this national representative sample,
called a State Monitoring Plan (or State Plan), will include the list
of systems statistically selected for UCMR monitoring. Other state
responsibilities will be defined in the Memorandum of Agreement issued
between the States and EPA. The State can review, and modify if
necessary, the list of systems in the State Plan. The resulting State
Plans will then be part of a national sample framework, providing the
representative national sample requisite to drawing national
conclusions for contaminant exposure.
To provide a more capable understanding of contaminants and
conditions affecting small systems, and to provide additional quality
assurance, EPA will randomly select up to 30 small public water systems
from the systems in State Monitoring Plans as ``Index'' systems. Index
systems must monitor every year during the five year UCMR listing
cycle. These systems will also be required to report information on
system operating conditions (such as water source, pumping rates, and
environmental setting). This information will assist EPA in more fully
evaluating small system operations and future regulations of small
systems. EPA will conduct the sampling and testing for Index systems.
At the time of sampling, EPA will also gather other system information
to characterize the environmental setting affecting the system
including precipitation, land and water resource use, and environmental
factors (such as soil type and geology).
Also, up to 150 additional small systems might be selected for the
Pre-Screen Testing. The systems for the Pre-Screen Testing will be
selected on the basis of their representativeness of systems most
vulnerable to the particular UCMR (1999) List 3 contaminants for which
methods have been refined. The statistical selection of the 800 systems
for the national representative sample may not include the systems
determined to be most vulnerable to these contaminants, hence; the
States and EPA may need to select additional systems for this targeted
testing.
External expert peer review and public comments supported the
statistical approach described to select small systems for the national
representative sample and State Monitoring Plans.
C. Type of Monitoring Required of Public Water Systems Based on Listing
Group
At the UCMR Stakeholders Meeting on June 3-4, 1998, a diverse group
of stakeholders suggested that the UCMR Program be developed through a
progression of monitoring levels based on contaminant group
characteristics. These characteristics reflect current information
about both the occurrence of and method availability for the
contaminants. Occurrence information and methods availability will
determine which phase, or tier, of monitoring the contaminants will be
placed. Both EPA and stakeholders are also concerned about contaminants
that may be ``emerging'' as contaminants of concern. These emerging
contaminants have not been monitored before, but have the potential to
be found near or in drinking water supplies or recently have been
identified as potential health problems. It is not likely that there
exists approved EPA analytical methods for the ``emerging contaminants
of concern''. Typically, ``research'' analytical methods are used to
detect such emerging contaminants and may be expensive. EPA will have
to either develop an approved method for inclusion in a regulatory
approach, or perhaps substitute a regulatory approach with a study
using a single laboratory and a ``research'' analytical method. The
resources needed to develop an approved analytical method will face
competing resource demands for other contaminants on the CCL that also
require analytical method development. In recognition of these
considerations, as described above, the final rule incorporates an
approach with three monitoring levels, or tiers, referred to as
``Assessment Monitoring,'' ``Screening Survey,'' and ``Pre-Screen
Testing''.
1. Assessment Monitoring
The first type of monitoring in the three-tiered monitoring program
of today's rule pertains to the group of contaminants for which
analytical methods are currently available and are specified in
Sec. 141.40(a)(3), Table 1, UCMR (1999) List 1, Assessment Monitoring
Importantly, these contaminants are ones for which initial data for
PWSs indicate that the contaminants occur in at least two States or ten
public water systems and should be monitored to assess national
occurrence through the UCMR. Based on today's rule, all contaminants in
Sec. 141.40(a)(3), Table 1, List 1 must be monitored in the Assessment
Monitoring tier of the UCMR Program, except perchlorate and acetochlor,
for which analytical methods are soon to be finalized.
In Sec. 141.40, EPA indicates that each system must conduct UCMR
``Assessment Monitoring'' of List 1 contaminants for a twelve-month
period in the first three years (i.e., 2001 through 2003) of a five-
year UCMR contaminant listing cycle (i.e., 2001 through 2005). Large
systems must complete this monitoring in any twelve-month period within
the years 2001 to 2003. Small systems in State Monitoring Plans must
complete the monitoring according to the scheduled monitoring
identified in those plans within the period of 2001 to 2003. Section F,
``Representative Sample of Systems Serving 10,000 or fewer persons,''
describes in detail the selection of the subset of small systems
required to monitor. The State could specify in the State Monitoring
Plans a schedule that would correlate with compliance monitoring. This
arrangement should enable systems to complete UCMR
[[Page 50568]]
sampling coincident with their compliance monitoring for regulated
contaminants during one of the years when compliance monitoring is
required. However, EPA recognizes that some large systems may not be
required to monitor for any regulated contaminants during the five-year
UCMR listing cycle. In that case, such large systems could monitor for
the unregulated contaminants during any twelve-month period within the
three years they choose. This approach, as originally proposed, is
responsive to public comments that UCMR monitoring be able to be
conducted in conjunction with compliance monitoring.
EPA is requiring that surface water systems monitor for four
consecutive quarters in the designated, or, in the case of large
systems, selected, monitoring year, and that ground water systems
monitor two times approximately five to seven months apart in their
monitoring year. Under Assessment Monitoring, systems serving more than
10,000 persons must conduct and pay for their own sample collection and
testing. Small systems included in State Monitoring Plans must collect
the samples with EPA-supplied equipment and send the samples to EPA-
specified laboratories. EPA will pay for the testing and reporting.
Although the laboratory may report the information directly to EPA and
provide a copy to the State, the system still has final reporting
responsibility to ensure that results are reported to EPA and copied to
the State. Frequency and location of monitoring are discussed in
section D, ``Monitoring Requirements under the Final UCMR.''
2. Screening Surveys
The contaminants that EPA is considering for the Screening Survey
are listed in Sec. 141.40(a)(3), Table 1, List 2. These contaminants
are those for which analytical methods are under development and for
which EPA has less occurrence data than for the contaminants on List 1.
The purpose of the Screening Survey is to analyze for contaminants
where the use of newly developed, non-routine analytical methods are
required. To do this and still maintain adequate quality of the
occurrence data, EPA will use only a select, controlled group of
laboratories. In addition, the Screening Survey approach might allow
EPA to maximize scientifically-defensible occurrence data for emerging
contaminants of concern more quickly than could be obtained through a
more standard unregulated contaminant monitoring effort. The Screening
Survey could, for example, be useful where questions concerning whether
a contaminant of concern is in fact occurring in drinking water and the
range of concentration of that occurrence. The Screening Survey is also
intended to allow EPA to screen contaminants to see if they occur at
high frequencies or concentrations that justify inclusion in future
unregulated contaminant Assessment Monitoring or at sufficiently low
frequencies that do not require further monitoring, but allow the
Agency to evaluate standard development.
The contaminants in UCMR (1999) List 2 will be monitored by a
smaller, statistically selected sample from all (large and small)
community and non-transient non-community water systems (about 300
systems total). These systems will be selected through a random number
generator. Systems will not have to initiate Screening Surveys until
after EPA promulgates requirements for Screening Surveys. The sample
size needed for estimating frequencies of contaminant occurrence are
smaller if the actual occurrence frequencies are close to 0 or to 100
percent. When a contaminant is consistently present or consistently
absent it requires fewer samples to determine its frequency with
adequate statistical confidence than if it occurs about half the time.
Only 300 PWSs are needed to determine if a contaminant is present 5
percent of the time or less frequently, at a 99 percent confidence
level and with a 3 percent margin of error. (The same criteria require
1,844 samples when the frequency could be any number.) If the
contaminant occurrence findings are above the thresholds established
for the Screening Survey, EPA will include the contaminant in the next
Assessment Monitoring round (projected to begin in 2006) of the UCMR
Program. The statistical threshold for positive results from this
monitoring to determine if further monitoring is warranted might be 1
to 2 percent of systems with detections. If the contaminant occurrence
were under the threshold, then no further testing would be required,
and the contaminant may be removed from the list in a future UCM
rulemaking. EPA requested public comment on whether the statistical
threshold of 1 to 2 percent of systems is adequate to make a
determination that further Assessment Monitoring should be conducted to
determine the extent of contaminant occurrence, and, if not, what
percent should be used as the threshold for such a determination. One
commenter suggested that EPA should use a threshold of 3 to 5 percent,
but did not provide any rationale. EPA believes that 1 to 2 percent is
consistent with the approach that this monitoring is a Screening Survey
to determine whether the contaminant(s) are occurring in any public
water system. One to 2 percent occurrence is equal to 3 to 6 systems
for the sample, but statistically this can be extrapolated to 600 to
1,200 systems out of all small systems that may have an occurrence of
the contaminants. For a sample size of 300, occurrence of a contaminant
on the monitoring list in any system would indicate that the
contaminant occurs at a frequency greater than 0 (zero). Therefore, EPA
should give further consideration to the occurrence and concentration
of such a contaminant and may evaluate the extent of its occurrence
nationally. EPA considers this extent of occurrence to be significant
and to warrant more extensive monitoring, perhaps even through
Assessment Monitoring. Another commenter indicated that EPA should
evaluate other factors and not just the extent of occurrence before
deciding to regulate a contaminant. EPA agrees with this comment and
will continue to evaluate other factors.
The anticipated analytical methods that might be used for Screening
Surveys are identified in Sec. 141.40(a)(3), Table 1, List 2, as
``Analytical Methods.'' These methods are being refined for the
particular contaminants on List 2 and are not expected to be ready for
use in an Assessment Monitoring program. Therefore, as analytical
methods are developed for groups of contaminants on List 2, EPA will
propose a rule modification for public comment and will promulgate
analytical methods, minimum reporting levels and the location and
timeframe for sampling for each contaminant.
Additionally, EPA requested public comment on two potential
outcomes from the Screening Survey: (1) if the contaminant is observed
at very few or no PWSs (i.e., less than the threshold of 1 to 2 percent
of systems), then the contaminant may be dropped from the UCMR (1999)
List 2 and no further monitoring for it will occur; and, (2) if the
contaminant is observed extensively (i.e., in a higher percentage of
PWSs, such as 5 to 10 percent) and EPA has health effects data for the
contaminant that indicate a significant concern, then that specific
contaminant may move directly to the regulation development stage. In
these cases, there may be no Assessment Monitoring tier of monitoring
activity to provide additional occurrence data for that contaminant.
One commenter expressed concern that EPA would move directly to
regulation development after obtaining results from Screening Surveys
for a contaminant and stated
[[Page 50569]]
that EPA should move the contaminant up to Assessment Monitoring before
taking any action. EPA believes that an occurrence of a contaminant in
5 or 10 percent of systems, for example, in the screening survey may be
sufficient to determine whether or not to initiate regulation
development. EPA may decide that it needs more information, in which
case, EPA could move the contaminant to Assessment Monitoring (List 1)
for more extensive monitoring to inform the regulatory process, but
this may not always be necessary.
With respect to funding the Screening Survey, EPA will pay for the
testing and reporting (as described in Preamble section V.G., Reporting
of Monitoring Results) for systems serving 10,000 or fewer persons.
Systems serving 10,000 or fewer persons will be responsible for sample
collection and preparing the samples for shipment. EPA will pay for the
shipment of these samples to an EPA-designated laboratory for testing
and for reporting of monitoring results to EPA, with a copy to the
State.
For large systems serving more than 10,000 persons, EPA requested
public comment on whether it should set performance standards and allow
systems to conduct their own laboratory analyses in compliance with the
standards, or should approve a limited but sufficient number of
laboratories to do lab analyses for large systems, providing for
quality control across a manageable number of laboratories while
allowing competitive pricing of services. Most commenters, including
water system operators, favored EPA approval of a limited number of
laboratories, but noted that a sufficient number of laboratories were
needed so that competitive pricing would be available.
EPA expects the Screening Surveys will occur one or two times
during the five-year listing cycle of 2001 through 2005. EPA expects
that this Screening Survey monitoring will occur for groups of
contaminants, rather than for one contaminant at a time, depending on
when the different methods are promulgated and the timing of their
promulgation. Systems selected for the Screening Surveys will monitor
at the same frequency as for contaminants under Assessment Monitoring.
Should approval and implementation of the analytical method for a
particular contaminant become delayed, the contaminant might be moved
into the category of Pre-Screen Testing, described next.
3. Pre-Screen Testing
The third tier of the final monitoring program is ``Pre-Screen
Testing'', which will be conducted for contaminants with analytical
methods that are in an early stage of development and at systems that
are determined to be most vulnerable to the occurrence of contaminants
on the Pre-Screen Testing list. Pre-Screen Testing means sampling,
testing, and reporting of the listed contaminants that have newly
emerged as drinking water concerns and, in most cases, for which
methods are in an early stage of development. Pre-Screen Testing will
be performed to determine whether a listed contaminant occurs in
sufficient frequency in the most vulnerable systems or sampling
locations to warrant its being included in future Assessment Monitoring
or Screening Surveys. Pre-Screen Testing will only be required after
additional rulemaking.
EPA will select a limited number of systems (up to 200) to conduct
Pre-Screen Testing, possibly using a random number generator, selected
from up to 25 of the most vulnerable systems identified by each State,
or by EPA if a State decides not to participate in the Pre-Screen
Testing system selection process. Up to 200 systems, a smaller sample
size than under the Screening Survey or Assessment Monitoring, are
considered sufficient for this type of monitoring because monitoring
will occur at systems determined to be vulnerable to occurrence of the
contaminants, based on the characteristics of the contaminants, system
operation, climatic conditions, and land and water resource use. This
monitoring is to determine whether the contaminant can be found in any
public water system under most likely occurrence conditions specific to
the contaminant. This tier of monitoring is not designed to determine
the extent of occurrence. A portion (e.g., 100 to 150) of these 200
systems may be a different subset of small systems serving 10,000 or
fewer persons than those selected for the national representative
sample. The reason for this different subset is that States should
identify the systems that are representative of the most vulnerable
conditions for the contaminants specified for Pre-Screen Testing. These
most vulnerable systems may not be those conducting Assessment
Monitoring or the Screening Survey. It is possible, though, that some
overlap of systems doing Assessment Monitoring and those selected for
Pre-Screen Testing could occur.
Under Pre-Screen Testing, EPA will designate or approve a
laboratory or laboratories to conduct sample analysis. The reason for
this testing approach is that the analytical methods expected to be
used will be emerging from research development, and most laboratories
will not have any experience with them. For these laboratories to
utilize the new methods could involve extensive investment in equipment
and training. Rather than requiring this investment for contaminants
which have uncertain occurrence in public water systems, EPA will
develop and promulgate appropriate methods. EPA will also require that
these methods be used by designated or approved laboratories. Pre-
Screen Testing analysis is conducted at systems most likely to have the
contaminants to determine whether further action is warranted and
additional method development is needed.
Under this approach, once EPA has developed methods and promulgated
the rule to test for List 3 contaminants, it will request States to
identify at least 5 and not more than 25 systems (based on the
population served by PWSs in each State) most vulnerable to the listed
contaminants. States will select these systems from all community and
non-transient non-community systems of all sizes. Selection criteria
for these systems include States' determination of systems most
vulnerable to the specified contaminants and numbers of systems per
State based on the population served in each size category of system.
The States will send the list of systems, any modification of their
State Monitoring Plans, and the reasons for their list and
modifications (considering the characteristics of the contaminants,
precipitation, system operation, and environmental conditions) to the
EPA. EPA will select up to 200 PWSs nationwide, from the pool of State-
identified vulnerable systems, that must submit samples of the
specified contaminants. Some small systems selected may not be part of
the national representative sample of 800 small systems selected for
Assessment Monitoring. Hence, some small systems may only be required
to sample for Pre-Screen Testing. States or EPA will provide
instructions to the systems for the necessary sampling and subsequent
shipping to the EPA laboratory. At this time, EPA believes that the
contaminants for which Pre-Screen Testing will likely be required are
those listed in the final rule at Sec. 141.40(a)(3) Table 1, List 3.
Sampling and testing done for Pre-Screen Testing will most likely be
required in the later years of the five-year UCMR listing cycle. This
approach will assist EPA in refining the methods for these
contaminants. If EPA finds any substantial frequency of occurrence of
Pre-Screen Testing contaminants, the contaminants could
[[Page 50570]]
become part of either the Screening Survey or part of Assessment
Monitoring in future UCMR lists. Since the methods for these
contaminants will have to be applied under highly controlled analytical
conditions, EPA will pay for the shipping and analyses of these samples
for small systems selected to participate. Large systems will pay for
the shipping and testing of samples at EPA approved laboratories.
Public comments requested that EPA provide guidance on the
selection of ``most vulnerable'' systems and on reporting requirements
for Pre-Screen Testing. EPA plans to provide this guidance during the
years 2001 and 2002, and obtain public comment before the guidance is
final.
D. Monitoring Requirements Under the Final UCMR
1. Monitoring Frequency
(a) Systems Serving More Than 10,000 Persons
(i) Chemical Contaminants.
The number of persons served affects exposure to contaminants and
resources necessary to monitor. The final UCMR program requires large
systems serving more than 10,000 persons to monitor at each entry point
to the distribution system, or other representative compliance
monitoring location specified by the State, whether or not the system
applies treatment. If a system applies treatment, then it must monitor
after treatment. In response to public comment, EPA modified the rule
to allow alternative sampling points to be used: sampling points
identified by the State for compliance monitoring under 40 CFR
141.24(f)(1), (2), and (3), and/or source (raw) water sampling points,
if the State uses source water monitoring as a more stringent
monitoring requirement. If monitoring at source (raw) water sampling
points indicates detection of any of the contaminants on the monitoring
list, then the system in most cases will be required to shift its
unregulated contaminant monitoring to the entry point to the
distribution system. These flexibilities in the sampling location
should enable systems and States to coordinate compliance and
unregulated contaminant monitoring more extensively.
The law requires EPA to consider the source of water relative to
unregulated contaminant monitoring requirements (SDWA Section
1445(a)(2)(A)). Over the twelve-month period of monitoring, the
regulation requires that systems sample from all entry points to the
distribution system, or other sampling points specified, representing
all principal, non-emergency sources of water used over the monitoring
period. Surface water-supplied systems will monitor each of these
points every three months for a twelve-month period and ground water-
supplied systems will monitor each of these points two times five to
seven months apart within a twelve-month period. Today's final
monitoring frequency for surface water systems is the same as in the
previous program. For ground water systems, the two sampling events
must be approximately six months apart, increasing the frequency from
one sample in five years under the previous program to two. The reasons
for this increase are that while ground water typically moves slowly,
one sample is insufficient to characterize water quality at any
particular location and will not provide evidence of any changes over a
longer period of time. Furthermore, some ground water environments
transmit water more rapidly, potentially resulting in changes in water
quality over shorter timeframes. From a statistical standpoint, one
sample is not representative and will not allow the data to be used for
exposure assessment which uses an average annual value. This frequency
applied to the average of 6.2 entry points to the distribution system
for systems serving more than 10,000 persons will provide sufficient
data for an adequate statistical analysis of the varied conditions in
which these systems are located.
One of the monitoring events for both surface water and ground
water systems must occur at the most vulnerable time of year for the
PWS. The rationale for this approach is that it provides data
representing potential variation in contaminant concentration over the
course of a year. This potential variation in concentration is
necessary to evaluate exposure related to contaminant occurrence. Some
systems perform compliance monitoring on a quarterly basis and can
collect UCMR samples coincident with their compliance samples, and
therefore provide data on the range of variation. Other systems may
only conduct compliance monitoring once every third year and will
therefore have to collect additional samples under the UCMR. While one
UCMR sample could be collected coincident with this compliance sample,
EPA is requiring for ground water-supplied systems to take a second
sample five to seven months later. This requirement will provide the
necessary data on seasonal variation over a year to allow consistent
exposure assessments to be done with a range of concentrations.
Stakeholders supported this option. EPA originally proposed that the
second sample be collected exactly six months later. State commenters
indicated a need to provide flexibility to accommodate changes in
monitoring schedules. Therefore, EPA modified the regulation to allow
monitoring five to seven months before or after the initial vulnerable
period sampling event.
(ii) Microbiological Contaminants
For microbiological contaminants, the sampling frequency will be
two times within one year, with samples collected each time at two
different locations after treatment in the distribution system: a site
representative of water in the distribution system received by the
general population that the system serves and a site in the
distribution system representing the maximum residence time or lowest
disinfectant residual, depending on the contaminant. The frequency
should capture the most vulnerable time as well as a time five to seven
months later to provide an average exposure. Furthermore, precipitation
patterns may be a major factor in contaminant occurrence. Thus,
frequency of sampling should be tailored to the most vulnerable times
because increased seasonal precipitation may carry these contaminants
at higher concentrations than other times during the year.
(b) Systems Serving 10,000 or Fewer Persons
The final rule states that approximately one third of the small
systems (serving 10,000 or fewer persons) selected through the
representative sample, be sampled each year over a three-year period at
the frequencies indicated in Section D, ``Monitoring Requirements Under
the Final UCMR'' (1)(a) above. This allows a relatively even submission
of samples to be managed and tested by the EPA laboratory. EPA will pay
for the reasonable costs of monitoring (i.e., containers, shipping,
testing and reporting) for this representative sample of systems,
including Assessment Monitoring, Screening Survey, and Pre-Screen
Testing, and will conduct the analyses at its designated laboratories.
EPA, therefore will need to be able to manage the number of samples
being received at any time to closely correspond to the analytical
capacity of its laboratories. Some public commenters suggested that
sampling for microbiological contaminants not occur at the maximum
residence time in the distribution system, but at the point of lowest
disinfectant residual, since the
[[Page 50571]]
monitoring of concern is for effectiveness of treatment and booster
disinfection stations that may be in use in long distribution lines. In
response, EPA added another sampling point at the ``lowest disinfectant
residual'' in the distribution system. However, EPA maintained the
original sampling point location of ``maximum residence time'' because,
given potential chemical degradation over long periods of time in a
distribution system, such as for disinfection byproducts, the location
of maximum residence time can often be the location of lowest
disinfectant residual and, therefore, highest likelihood of
microbiological contaminants.
Public comments also addressed the flexibility in monitoring
schedules to allow for unforeseen events or factors in field sampling.
Specifically, States asked that system sampling schedules allow for
sampling over a month within a quarter, rather than exactly three
months later. EPA modified the final rule to allow sampling by small
and large surface water systems to occur within the same month in each
quarter and for small and large ground water systems, to occur any time
five to seven months before or after the initially selected month
within the vulnerable time.
2. Monitoring Time for Vulnerable Period
Water quality studies and monitoring throughout the United States
have clearly shown that contaminant occurrence and/or concentration
vary over time, both seasonally as well as from year to year. The
seasonality of occurrence, or period of peak concentration of
contaminants, commonly varies with seasonal changes in the hydrologic
cycle in relation to the source of contaminants and their fate and
transport characteristics. Particularly for land-applied or land-
disposed contaminants, the increased flux of water mobilizes the
contaminants and moves them into surface or ground water flow systems.
For the most vulnerable of water systems, such as surface waters,
unconfined shallow ground water and karst flow systems, for example,
higher levels of contaminant concentrations typically occur during
annual runoff and recharge periods. For much of the United States, east
of the Rocky Mountains, many studies have shown that the season of
greatest vulnerability for contaminant occurrence is the late-spring,
early-summer runoff-recharge period, particularly for contaminants such
as pesticides and nitrate (e.g., Larson et al., 1997; Barbash and
Resek, 1996; Hallberg, 1989a,b). For deeper, more confined ground water
systems, defining vulnerable periods is much more difficult. The exact
flow path and time of travel are much greater and more complex and are
dependent upon many factors unique to a particular well and aquifer
setting (e.g., Hallberg and Keeney, 1993). There is no generality that
can be applied to these latter settings.
Because occurrence may vary seasonally, it is important to try to
capture these vulnerable periods in a one-time survey of contaminant
occurrence such as the UCMR. Statistical studies of sampling strategies
in surface water (e.g., Battaglin and Hay, 1996) have shown that
incorporating sampling during spring and early summer runoff periods
provides a more accurate representation of annual occurrence than
random quarterly sampling (that can avoid these months). Ground water
studies (e.g., Pinsky et al., 1997) suggest that the more vulnerable
ground water settings also show peaks during these periods. The default
vulnerable period for sampling for the UCMR has been designated to
coincide with this period of peak vulnerability for much of the United
States: one sample must be collected during May, June, or July, unless
the State has better information to designate another period. Also, for
surface waters, three additional samples will be collected throughout
the year, and for ground water systems, one additional sample will be
collected five to seven months before or after the vulnerable time.
This additional sampling will also capture the winter recharge and
runoff period that may be more vulnerable in the western coastal
regions or warmer southern climates for some contaminants. In the case
of some deeper ground water systems, States or systems may have
additional knowledge of seasonal vulnerability patterns, in which case
the State can designate an alternative period for sampling.
Public comments generally supported monitoring in a vulnerable
time, but desired flexibility in establishing the time and frequency.
The rule already provided flexibility in selecting a time within the
May to July period for a sampling event. However, because the
statistical approach requires consistency, today's rule enables a State
to determine the alternate vulnerable time for monitoring, rather than
each system using its own criteria for choosing a vulnerable time. With
respect to frequency, the statistical approach requires that systems
monitor with the same frequency so that a national frequency
distribution can be developed. This precludes the State or a system
from establishing its own monitoring frequency.
Two commenters indicated that pumping rate and not hydrologic
factors accounted for variations in contaminant concentration, with
higher pumping rates coinciding with higher concentrations. No specific
data were offered in support of these comments. EPA believes that many
factors may account for higher contaminant concentrations during
certain seasons. While pumping rate may be a factor, hydrologic factors
are documented as having a significant influence in concentrations of
pesticides and other contaminants, as noted previously. A State may use
pumping rates as a basis for designating an alternative vulnerable time
if determined appropriate.
3. Monitoring Location
In Sec. 141.40(a)(3), today's action identifies entry points to the
distribution system (EPTDS) after any treatment, or the sampling points
specified by the State for compliance monitoring under 40 CFR
141.24(f)(1), (2), and (3), representative of each principal, non-
emergency water source in use over the twelve-month period of
Assessment Monitoring, as the sampling locations for List 1
contaminants. Also, two sites in the distribution system (a site
representative of water in the distribution system received by the
general population that the system serves and a site in the
distribution system representing the maximum residence time or the
lowest disinfectant residual) are designated for microbiological or
distribution system contaminants. Sampling at entry points to the
distribution system after any treatment follows the existin ![[logo] US EPA](http://www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}