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Revisions to the Unregulated Contaminant Monitoring
Regulation for Public Water Systems; Proposed Rule
Related Material
[Federal Register: April 30, 1999 (Volume 64, Number 83)]
[Proposed Rules]
[Page 23397-23458]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr30ap99-28]
[[Page 23397]]
_______________________________________________________________________
Part II
Environmental Protection Agency
_______________________________________________________________________
40 CFR Parts 141 and 142
Revisions to the Unregulated Contaminant Monitoring Regulation for
Public Water Systems; Proposed Rule
[[Page 23398]]
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 141 and 142
[FRL-6329-3]
RIN 2040-AD15
Revisions to the Unregulated Contaminant Monitoring Regulation
for Public Water Systems
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
-----------------------------------------------------------------------
SUMMARY: The Safe Drinking Water Act (SDWA), as amended in 1996,
requires the Environmental Protection Agency (EPA) to establish
criteria for a monitoring program for unregulated contaminants and, by
August 6, 1999, to publish a list of contaminants to be monitored. To
conform to the Amendments, EPA is proposing the Unregulated Contaminant
Monitoring Regulation for Public Water Systems (UCMR) to substantially
revise the current regulations for unregulated contaminant monitoring.
Under a separate action on January 8, 1999, EPA published a Direct
Final Rule suspending the existing monitoring requirements for systems
serving 10,000 or fewer persons, effective March 9, 1999. Prior to
March 9, 1999, the unregulated contaminant monitoring regulations
required public water systems to monitor for unregulated contaminants
during one year every five years. EPA promulgated the direct final rule
to allow systems serving 10,000 or fewer persons to save the cost of a
third monitoring round under the previous regulations, which if
performed as scheduled would have overlapped with monitoring
requirements expected to be promulgated in the UMCR in August 1999.
This proposed rule includes a new list of contaminants to be
monitored, procedures for selecting a national representative sample of
public water systems serving 10,000 or fewer persons that will be
required to monitor, the frequency and schedule for monitoring, and
procedures for placement of the monitoring data in the National
Drinking Water Contaminant Occurrence Data Base, as required under
section 1445 of SDWA, as amended. The data in the database will be used
to identify contaminants for 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 in developing standards for the contaminants the Administrator
selects.
DATES: The proposed rule is open to public comment until June 14, 1999.
ADDRESSES: Send written comments to the Comment Clerk, docket number W-
98-02, U.S. Environmental Protection Agency, Water Docket (MC 4101),
401 M Street, SW, Washington, DC 20460. Please submit an original and
three copies of your comments and enclosures (including references).
Commenters who want EPA to acknowledge receipt of their comments should
enclose a self-addressed, stamped envelope. No facsimiles (faxes) will
be accepted.
Comments may also be submitted electronically to ow-
docket@epamail.epa.gov. Electronic comments must be submitted as an
ASCII file avoiding the use of special characters and any form of
encryption. Electronic comments must be identified by the docket number
W-98-02. Comments and data will also be accepted on disks in
WordPerfect in 5.1 format or ASCII file format. Electronic comments on
this proposal may be filed online at many Federal Depository Libraries.
The full record for this proposal has been established under docket
number W-98-02 and includes supporting documentation as well as
printed, paper versions of electronic comments. The full record is
available for inspection from 9 a.m. to 4 p.m. Monday through Friday,
excluding legal holidays at the Water Docket, East Tower Basement,
USEPA, 401 M Street, SW, Washington DC. For access to docket materials,
please call (202) 260-3027 between 9 a.m. and 3:30 p.m, Eastern Time,
Monday through Friday, to schedule an appointment.
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 DC 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 a.m. to
5:30 p.m. Eastern Time.
SUPPLEMENTARY INFORMATION:
Regional Contacts
I. Anthony De Palma, JFK Federal Bldg., Room 2203, Boston MA 02203,
Phone: 617-565-3610.
II. Walter Andrews, 290 Broadway, Room 2432, New York, NY 10007-
1866, Phone: 212-637-3880.
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. Kim Harris, 77 West Jackson Blvd., Chicago, IL 60604-3507, Phone:
312-886-4239.
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. Larry Worley, 1200 Sixth Avenue, Seattle, WA 98101, Phone: 206-
553-1893.
Abbreviations and Acronyms Used in the Preamble and Proposed Rule
2,4-DNT--2,4-dinitrotoluene
2,6-DNT--2,6-dinitrotoluene
4,41'-DDE--degradation product of DDT
Alachlor ESA--alachlor ethanesulfonic acid, a degradation product of
alachlor
AOAC--Association of Official Analytical Chemist
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 and
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 di- and mono-acid degradates
--Degradation products of DCPA
DDE--Degradation product of DDT
DDT--Dichloro diphenyl trichloroethane, a general insecticide
EDL--Estimated detection limit
EPA--Environmental Protection Agency
EPTC--s-ethyl-dipropylthiocarbamate, an herbicide
EPTDS--Entry Point to the Distribution System
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
HLPC--High performance liquid chromatography, a laboratory method
ICR--Information Collection Request
IFRA--Initial regulatory flexibility analysis
IMS--Immunomagnetic separation
[[Page 23399]]
IRIS--Integrated Risk Information System
IS--Internal standard
LLE--Liquid/liquid extraction, a laboratory method
MAC--Mycobacterium avium intracellulare
MCL--Maximum contaminant level
MDL--Method detection limit
MRL--Minimum reporting level
MS--Mass spectrometry, a laboratory method
MS--Sample matrix spike
MSD--Matrix spike duplicate
MTBE--Methyl-tert-butyl-ether, a gasoline additive
NAWQA--National Water Quality Assessment Program
NCOD--National Drinking Water Contaminant Occurrence Data Base
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
PBMS--Performance-Based Measurement System
pCi/L--Picocuries per liter
PCR--Polymerase chain reaction
PWS--Public Water System
PWSF--Public Water System Facility
QA--Quality assurance
QC--Quality control
RDX--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
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 Regulations/Rule
UCM--Unregulated Contaminant Monitoring
ug/L--Micrograms per liter
UMRA--Unfunded Mandates Reform Act of 1995
USEPA--United States Environmental Protection Agency
UV--Ultraviolet
VOC--volatile organic compound
Preamble Outline
I. Why the Unregulated Contaminant Monitoring Regulation Is Changing
II. Current Unregulated Contaminant Monitoring
A. Current Program
B. Status of Unregulated Contaminants on the Current Monitoring
List
III. Proposed 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 Monitoring List
(b) Regulatory Options
(c) Analytical Methods Applicable to the Monitoring List
(i) Chemical Analytical Methods
(ii) Microbiological Analytical Methods
(d) Screening Methods
2. List of Contaminants To Be Monitored
(a) Proposed Monitoring List
(b) Number of Contaminants on the Monitoring List
(c) Modifying the Monitoring List through the Governors'
Petition
(i) Circumstances Affecting the Governors' Petition
(ii) Response to Governors' Petition
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
4. Option to the Three-Tiered Approach
D. Monitoring Requirements under the Proposed UCMR
1. Monitoring Frequency
(a) Systems Serving more than 10,000 persons
(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. Relations to Compliance Monitoring Requirements
7. Previous Monitoring of the Contaminants Proposed for the
Monitoring List
8. Regulatory Options considered for large systems
(a) Which large systems should monitor
(b) Monitoring Frequency
(c) Monitoring Location
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) Non-Transient Non-Community Water Systems
(c) Transient Non-Community Systems
3. Geographic location within the State
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 as a Separate Group
(d) ``Index'' Systems
(e) Other State Data
6. Regulatory Options
G. Reporting of Monitoring Results
1. PWS and State Reporting to EPA
2. Regulatory Options
3. Timing of Reporting
4. Method of Reporting
5. Public Notification of Availability of Results
6. Voluntary Reporting
IV. Implementation of Today's Proposal
A. Setting an Effective Date
B. Primary Program Revision
C. Implementation in Indian Country
D. Establishing the Laboratory Testing Program
1. Analytical Methods for the Testing Program
2. Testing Program for systems serving more than 10,000 persons
3. Testing Program for systems serving 10,000 or fewer persons
E. Continued Analytical Methods Development
F. Determining the National Representative Sample and State
Monitoring Plans
G. Specifying the Vulnerable Monitoring Period
H. Conducting the Sampling
I. Screening Survey
J. Pre-Screen Testing
K. Testing
L. Reporting Requirements
M. Record Keeping
N. Modifying the Monitoring List
O. Funding for Testing of Sample for Systems in State Monitoring
Plans and for Pre-Screen Testing
(1) Assessment Monitoring
(2) Screening Survey.
(3) Pre-Screen Testing
V. Relation of the Proposed Regulation to the Existing Regulation
VI. Cost and Benefit of a Revised UCMR Program
A. Program Cost Estimates
B. Net Costs
C. Benefits
VII. Performance-Based Measurement System
VIII. Solicitation of Public Comment
IX. 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
F. National Technology Transfer and Advancement Act
G. Executive Order 12898--Federal Actions to Address
Environmental Justice in Minority Populations and Low-Income
Populations
[[Page 23400]]
H. Executive Order 12875--Enhancing Intergovernmental
Partnerships
I. Executive Order 13084--Consultation and Coordination with Indian
Tribal Governments
X. Public Involvement in Regulation Development
XI. 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 would be required to monitor. A community water
system means a public water system which serves at least 15 public
service connections used by year-round residents or regularly serves at
least 25 year-round residents. Non-transient non-community water system
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 would be
regulated by this action. Categories and entities that may ultimately
be regulated include the following:
------------------------------------------------------------------------
Examples of potentially
Category regulated entities SIC
------------------------------------------------------------------------
State, Tribal and Territorial States, Territories, and Tribes 9511
Governments. that analyze water 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 4941
and non-transient non-community
water systems required to
monitor.
Municipalities................ Municipal operators of community 9511
and non-transient non-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
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. Why the Unregulated Contaminant Monitoring Regulation Is
Changing
The current Unregulated Contaminant Monitoring Program operating
under the Safe Drinking Water Act (SDWA, the Act) requires public water
systems to monitor for unregulated contaminants during one year every
five years. Under section 1445(a)(2) of the Act, as amended in 1996,
the Environmental Protection Agency (EPA) is required to establish
criteria for a monitoring program for unregulated contaminants and, by
August 6, 1999, to publish a list of contaminants to be monitored. To
conform to the 1996 Amendments, EPA is proposing substantial revisions
to the Unregulated Contaminant Monitoring (UCM) Program, currently
described in 40 CFR 141.40. The purpose of the Unregulated Contaminant
Monitoring Program is to collect occurrence data to help determine
which contaminants EPA should regulate based on their concentrations in
public water systems and their adverse health effects levels.
This proposed rule will take the place of the regulations currently
in 40 CFR 141.35, 141.40, and 142.15(c)(3) and modify Sec. 142.16. The
revisions cover the following: (1) The frequency and schedule for
monitoring based on public water system (PWS) size, water source, and
likelihood of finding the contaminants; (2) a new shorter list of
contaminants to be monitored, (3) procedures for selecting and
monitoring a national representative sample of public water systems
serving 10,000 or fewer people, and (4) procedures for placing the
monitoring data in the National Drinking Water Contaminant Occurrence
Data Base (NCOD), as required under Section 1445. The data generated by
this rule, when adopted, will be used to identify contaminants for the
Contaminant Candidate List (CCL), to support the Administrator's
determination of whether or not to regulate a contaminant under the
drinking water program, and to support the development of drinking
water regulations. The proposed revised UCM Program is a cornerstone of
the sound science approach to future drinking water regulation, which
is one of the aims of the SDWA Amendments.
In a separate action, EPA has published a Direct Final Rule (64 FR
1494, January 8, 1999) which will cancel the existing monitoring
requirements for systems serving 10,000 or fewer persons effective
January 1, 1999. The Direct Final Rule will modify the existing
regulations ahead of this Proposed Rule to revise the existing
unregulated contaminant monitoring regulations. The Direct Final Rule's
purpose is to allow the systems serving 10,000 or fewer persons to save
the cost of a third monitoring round under the existing regulation,
which if performed would overlap with monitoring under the proposed
revised rule. EPA believes that it has sufficient data from the
previous monitoring rounds to make decisions concerning the status of
the contaminants on the existing monitoring list (see Table 1).
II. Current Unregulated Contaminant Monitoring
A. Current Program
The current Unregulated Contaminant Monitoring Program was
established in the SDWA, as amended in 1986, and implemented by
regulation in 1987 (52 FR 25720, July 8, 1987). The program was revised
three times thereafter (56 FR 3526, January 30, 1991; 57 FR 22178, May
27, 1992; and 57 FR 31776, July 17, 1992). Under 40 CFR 141.40, public
water systems are required to monitor for up to 48 unregulated
contaminants and under 40 CFR 141.35, to report monitoring results to
the States, or to EPA if a State does not have primacy to administer
the State Drinking Water Program. These 48 contaminants are listed in
Table 1 of this Preamble, along with their regulatory status. Under 40
CFR 142.15, primacy States must report monitoring results to EPA.
Repeat monitoring and reporting are required during one year every 5
years. Systems serving fewer than 150 service connections may make
their facilities available for the States to monitor, rather than
perform their own monitoring.
B. Status of Unregulated Contaminants on the Current Monitoring List
Based on the results of the current Unregulated Contaminant
Monitoring
[[Page 23401]]
Program, EPA analyzed each of the 48 contaminants on the current list.
The status of the 48 contaminants as a result of that analysis is
summarized below in Table 1.
Table 1.--List and Status of the Current Unregulated Contaminants
--------------------------------------------------------------------------------------------------------------------------------------------------------
Covered by
In regulation On contaminant Did not occur other Did not meet
development \1\ candidate list at significant regulatory health effects
\2\ levels \3\ action \4\ level \5\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Aldicarb........................................................... X
Aldicarb sulfone................................................... X
Aldicarb sulfoxide................................................. X
Aldrin............................................................. ............... X
Bromobenzene....................................................... ............... X
Bromochloromethane................................................. X
Bromodichloromethane............................................... X
Bromoform.......................................................... X
Bromomethane (methyl bromide)...................................... ............... X
Butachlor.......................................................... ............... ............... X
sec-Butylbenzene................................................... ............... ............... ............... ............... X
n-Butylbenzene..................................................... ............... ............... ............... ............... X
tert-Butylbenzene.................................................. ............... ............... ............... ............... X
Carbaryl........................................................... ............... ............... X
Chlorodibromomethane............................................... X
Chloroethane....................................................... X
Chloroform......................................................... X
Chloromethane...................................................... X
o-Chlorotoluene.................................................... ............... ............... X
p-Chlorotoluene.................................................... ............... ............... X
Dibromomethane..................................................... X
Dicamba............................................................ ............... ............... X
m-Dichlorobenzene.................................................. ............... ............... X
Dichlorodifluoromethane............................................ ............... ............... X
1,1-Dichloroethane................................................. ............... X
2,2-Dichloropropane................................................ ............... X
1,3-Dichloropropane................................................ ............... X
1,1-Dichloropropene................................................ ............... X
1,3-Dichloropropene................................................ ............... X
Dieldrin........................................................... ............... X
Fluorotrichloromethane............................................. ............... ............... X
Hexachlorobutadiene................................................ ............... X
3-Hydroxycarbofuran................................................ ............... ............... ............... X
Isopropylbenzene................................................... ............... ............... X
p-Isopropyltoluene................................................. ............... X
Methomyl........................................................... ............... ............... X
Metolachlor........................................................ ............... X
Metribuzin......................................................... ............... X
Naphthalene........................................................ ............... X
Propachlor......................................................... ............... ............... X
n-Propylbenzene.................................................... ............... ............... X
Sulfate............................................................ ............... X
1,1,1,2-Tetrachloroethane.......................................... ............... ............... X
1,1,2,2-Tetrachloroethane.......................................... ............... X
1,2,3-Trichlorobenzene............................................. ............... ............... ............... X
1,2,3-Trichloropropane............................................. ............... ............... X
1,2,4-Trimethylbenzene............................................. ............... X
1,3,5-Trimethylbenzene............................................. ............... ............... ............... ............... X
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ In Regulation Development means that EPA is currently working on regulations affecting the contaminant in drinking water.
\2\ On Contaminant Candidate List means that the contaminant is on the CCL for EPA to determine whether or not to regulate it in the future.
\3\ Did Not Occur at Significant Levels means that unregulated contaminant monitoring results and other data did not indicate widespread occurrence or
concentrations that would warrant further action.
\4\ Covered By Other Regulatory Action means that the contaminant is addressed through regulation of other contaminants.
\5\ Did Not Meet Health Effects Level means that the concentrations reported in unregulated contaminant monitoring results or other data were not at or
above health effects levels established by EPA or other organizations that have such health indicators.
[[Page 23402]]
III. Proposed 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 Monitoring List
Section 1445(a)(2)(B) requires EPA to list not more than 30
unregulated contaminants to be monitored by public water systems. Today
EPA is proposing to use the 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. The
criteria used in the CCL for identifying contaminants for which
occurrence data are needed are:
(i) Whether sufficient data exist on the occurrence or likely
occurrence of the contaminant in drinking water, including production,
release, and use to warrant further confirming data; and
(ii) Whether sufficient data exist to indicate the occurrence of
the contaminant in two or more States, or in ten or more public water
systems.
The other criterion is whether an analytical method exists for the
contaminant. The other mechanism for selecting contaminants for UCMR
monitoring is through the petition of seven or more State governors to
EPA, described below under III.A.2.(c), Modifying the Monitoring List
through the Governors' Petition.
The CCL was developed with the advice of the Working Group on
Contaminant Occurrence and Selection of the National Drinking Water
Advisory Council (NDWAC), formed pursuant to the Federal Advisory
Committee Act (FACA). The group developed criteria, adopted by EPA, for
deciding which contaminants to include on the CCL.
Criteria for selecting contaminants for the CCL focused on
occurrence in water at levels of health concern, or indications of
occurrence (production or release, coupled with contaminant
properties). EPA used health effects concentrations to determine the
significance of occurrence levels. When developing the CCL, EPA used
the previous unregulated contaminant monitoring data from States as one
of the many sources of occurrence data. The term ``occurrence'' as used
here means the measured observation of a substance in drinking water or
potential source of drinking water. The 1998 CCL contains 50 chemical
contaminants and 10 microbiological contaminants. The process for
developing the CCL is described in more detail in the March 2, 1998,
Federal Register containing the list (63 FR 10273).
When EPA began the process of choosing contaminants for the CCL,
EPA and NDWAC experts worked from a compendium of 8 lists containing
approximately 262 chemical contaminants. The lists used in this process
included the 1991 Drinking Water Priority List, health advisories,
Integrated Risk Information System, Non-Target Analytes in Public Water
Supply Samples, Comprehensive Environmental Response, Compensation and
Liability Act (CERCLA) Priority List, stakeholder responses, Toxic
Release Inventory, and pesticides identified by the Office of Pesticide
Programs. Contaminants not among the 262 chemical contaminants
initially identified were not considered in developing the CCL.
Table 2 lists all of the contaminants on the CCL and indicates
whether they are priorities for consideration under three categories--
regulation, research (health, treatment, and analytical methods), and
occurrence. (Contaminants may appear in more than one column of Table
2.) The groupings in Table 2 are based on current (1998) information,
and some movement of contaminants between categories can be expected as
more information is evaluated and analyzed. In Table 2, ``Regulation
Determination Priorities'' means that for the contaminants listed, EPA
believes it has or will soon have sufficient data to determine whether
or not to regulate these contaminants. ``Research Priorities'' means
that before EPA could make any regulatory determination, EPA would need
health effects data, treatment technology results, or analytical
methods development to test for the contaminants. ``Occurrence
Priorities'' indicates that EPA needs data to determine whether the
contaminant occurs or is likely to occur in drinking water of public
water systems. The ``Occurrence Priorities'' identify the contaminants
that EPA is focusing on in the Unregulated Contaminant Monitoring
Program proposed today. EPA believes that the purpose of this program
is to compile data concerning the occurrence of unregulated
contaminants in drinking water so that, together with health effects
information, EPA can determine which unregulated contaminants are
priorities for future regulation.
[[Page 23403]]
Table 2.--Contaminant Candidate List (CCL)
----------------------------------------------------------------------------------------------------------------
Research priorities
Regulatory --------------------------------------------------------------------- Occurrence
determination Analytical methods priorities
priorities Health research Treatment research research
----------------------------------------------------------------------------------------------------------------
Acanthamoeba Aeromonas hydrophila Adenoviruses Adenoviruses Adenoviruses
(guidance) Cyanobacteria (Blue- Aeromonas hydrophila Cyanobacteria (Blue- Aeromonas hydrophila
1,1,2,2- green algae), other Cyanobacteria (Blue- green algae), other Cyanobacteria (Blue-
tetrachloroethane freshwater algae, green algae), other freshwater algae, green algae), other
1,1-dichloroethane and their toxins freshwater algae, and their toxins freshwater algae,
1,2,4- Caliciviruses and their toxins Caliciviruses and their toxins
trimethylbenzene Helicobacter pylori Caliciviruses Helicobacter pylori Caliciviruses
1,3-dichloropropene Microsporidia Coxsackieviruses (ICR Microsporidia Coxsackieviruses
2,2-dichloropropane Mycobacterium avium data) 1,2-diphenylhydrazine (ICR data)
Aldrin intercellulare (MAC) Echoviruses (ICR 2,4,6-trichlorophenol Echoviruses (ICR
Boron 1,1-dichloropropene data) 2,4-dichlorophenol data)
Bromobenzene 1,3-dichloropropane Helicobacter pylori 2,4-dinitrophenol Helicobacter pylori
Dieldrin Aluminum Microsporidia 2-methyl-Phenol Microsporidia
Hexachlorobutadiene DCPA mono-acid and di- Mycobacterium avium Acetochlor 1,2-
p-Isopropyltoluene acid degradates intracellulare (MAC) Alachlor ESA diphenylhydrazine
Manganese Methyl bromide Aluminum Fonofos 2,4,6-
Metolachlor MTBE MTBE Perchlorate trichlorophenol
Metribuzin Perchlorate Perchlorate RDX 2,4-dichlorophenol
Naphthalene Sodium (guidance) 2,4-dinitrophenol
Organotins 2,4-dinitrotoluene
Triazines and 2,6-dinitrotoluene
degradation products 2-methyl-phenol
(incl., but not Alachlor ESA
limited to Cyanazine Acetochlor
and atrazine- DCPA mono-acid and
desethyl) di-acid degradates
Sulfate DDE
Vanadium Diazinon
Disulfoton
Diuron
EPTC
Fonofos
Linuron
Molinate
MTBE
Nitrobenzene
Perchlorate
Prometon
RDX
Terbacil
Terbufos
----------------------------------------------------------------------------------------------------------------
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 or not to regulate
them. Today's proposal does 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). During
the process of identifying contaminants for the CCL and subsequently
for the UCMR, perchlorate had only been detected at a few sites in the
western U.S. However, perchlorate is increasingly being detected in
other parts of the country. A total of nine States have detected
perchlorate and as monitoring increases, other States are likely to
detect it. EPA seeks public comment on whether perchlorate and RDX
should be included in the UCM List.
For the remaining 32 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 microbiological
parameters for which suitable analytical methods are not currently
available. As listed in List 1 of Table 3 below, EPA identified 10
organic chemical contaminants and one microbiological contaminant for
which analytic methods are now available. List 1 contaminants are those
that are proposed today to be monitored beginning on the effective date
of this rule, as explained in 2., List of Contaminants to be Monitored.
List 2 of Table 3 lists 14 organic chemical contaminants for which
methods are being refined. List 3 of Table 3 identifies seven
microbiological contaminants for which methods are being researched.
Contaminants on Lists 2 and 3 are not proposed to be monitored until
EPA promulgates revisions to this rule to specify analytical methods
and related sampling requirements.
In addition, EPA requests comment on the addition to the
unregulated contaminant monitoring List 1 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 along with radium-226 and radon-222. Lead-210 with a half life
of 22 years, and one of its progeny, polonium-210, with a half life of
138 days, have been found in drinking water. EPA is aware of the
occurrence of these contaminant in shallow aquifers in Florida (Harada,
et al., 1989; Upchurch, 1991), and in at least two other states.
Because of potential occurrence and consequent health risks, EPA is
considering adding these contaminants to the monitoring list.
[[Page 23404]]
(b) Regulatory Options
EPA proposes in Sec. 141.40(a)(3) that the contaminants listed in
Lists 1-3 be used for the UCMR program monitoring list and be
categorized based on the availability of analytical methods. List 1 is
the basis for ``Assessment Monitoring.'' EPA proposes that ``Assessment
Monitoring'' occur at all 2,774 large community and non-transient non-
community systems serving more than 10,000 persons and a representative
sample of approximately 800 systems serving less than 10,000 or fewer
persons in State Monitoring Plans. List 2 will be the basis of a
``Screening Survey'' of approximately 300 of the systems required to do
Assessment Monitoring. List 3 will be used for ``Pre-Screen Testing''
at up to 200 systems selected because of potential vulnerability to the
specific contaminants. This monitoring approach is described in detail
under III.C. ``Type of Monitoring Required of Public Water Systems
Based on Listing Group.'' Assessment Monitoring would include only
those contaminants in List 1 for which analytical methods are included
in this regulation. Assessment Monitoring (and associated ``index
site'' monitoring described below) is the only monitoring that would be
required by today's proposal. This includes contaminants for which EPA
expects to have developed reference analytical methods by the year
2000.
For contaminants in List 2 for which analytical methods are
developed by the time of initial monitoring in 2001, EPA would amend
this rule to require the Screening Survey to be conducted at selected
systems. For those contaminants in List 2 and List 3 that do not have
well developed methods by the time of initial monitoring in 2001, EPA
would issue a revision to this regulation to activate the contaminants
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 would then
begin at a specified effective date in that prospective regulation.
Therefore, monitoring of contaminants on Lists 2 and 3 would not be
required by today's proposal and would only occur when EPA publishes a
revision to this regulation specifying the methods to be used and the
dates for monitoring to begin, at which time EPA would request public
comment on the methods. EPA solicits public comment on the selection of
these contaminants using the CCL priorities for contaminants needing
occurrence data before regulatory determination and the activation for
monitoring based on methods availability.
EPA believes 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 Monitoring List. This petition process allows for
the flexibility to include contaminants that are emerging as concerns
between the five-year listing cycles. EPA, however, does request public
comment on other criteria that the Agency may use to include
contaminants of concern on the UCM List that are not on the CCL and may
not be identified through a Governors' Petition, such as Polonium-210,
noted above.
(c) Analytical Methods Applicable to the Monitoring List
The Monitoring List is developed around the availability to
analytical methods for the listed contaminants and the level of
information available for them at this time. The discussion below
highlights analytical methods considerations in listing the
contaminants for monitoring. Only the contaminants identified on List 1
will be monitored as a result of today's proposal. Contaminants on
Lists 2 and 3 below are proposed for the Unregulated Contaminant
Monitoring List, but will not be activated for monitoring until EPA
believes that the analytical methods can be applied to obtain reliable
results. At that time, EPA will propose List 2 and 3 contaminants for
monitoring.
(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.
Before EPA establishes a Maximum Contaminant Level (MCL), the
Agency relies on a 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
compounds proposed 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 and proposed today by EPA
for conducting the chemical laboratory analyses is the following:
For PWSs serving more than 10,000 people, the PWS would be
responsible for sample collection and analyses for unregulated
contaminant Assessment Monitoring. This monitoring could be conducted
at the same time as the required compliance monitoring. For unregulated
contaminant Assessment Monitoring, however, EPA is proposing in
Sec. 141.40(a)(3) to require 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 proposal 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 testing quality control
requirements address use of a certified laboratory, sample collection/
preservation, analytical methods, method detection limit, calibration,
quality control sample, method performance test, detection
confirmation, and reporting.
The purpose for these 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 will provide a guidance manual to
further explain these quality control measures that would need to be
performed for all unregulated contaminant monitoring. For systems that
are part of State Plans for representative samples, the sampling
guidance, ``UCMR Guidance for Operators of Public Water Systems
[[Page 23405]]
Serving 10,000 or Fewer Persons'' is available. Drafts of the guidance
and manual ``UCMR Analytical Methods and Quality Control Manual'' are
available for public comment with this proposed rule through the EPA
Safe Drinking Water Hotline at 800-426-4791, or through EPA's Office of
Ground Water and Drinking Water Homepage at www.epa.gov/ogwdw. EPA
would apply these same testing and quality control procedures to the
samples of all monitored systems. These proposed procedures are
discussed in more detail in section 5, Monitoring Requirements under
the Proposed UCMR.
EPA is specifying the use of certain analytical methods that are
currently available for UCM (see Table 5, Unregulated Contaminant
Monitoring List, III A.2(a) 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 UCM 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)(4) and (5), and appendix A. EPA is requesting comments
on the methods which have been specified for the contaminants on the
UCM List.
The data quality needs associated with drinking water chemical
compliance monitoring and the evaluation and use of occurrence data are
different. The purpose of compliance monitoring is to determine whether
a compound is present currently in the drinking water above the
established MCL. However, the purpose of the UCM is to obtain
occurrence data to support future regulatory decisions. The data
required to make regulatory decisions must be of high quality. All
analytical methods are subject to false negatives (not detecting a
contaminant when it is present), false positives (either incorrectly
identifying or detecting a contaminant, or introducing a contaminant
into a sample when it is not present), and errors in the accuracy and
precision of quantitative results.
The control of false negatives is important for both compliance and
occurrence monitoring. However, using analytical methods which
inherently have fewer false positives or requiring quality control
elements that control false positives, is more critical in occurrence
than in compliance monitoring. There are much greater incentives
inherent in compliance monitoring (e.g., the possibility of enforcement
actions, the potential need to install expensive treatment systems,
etc., to confirm that the contaminant detected is indeed present) than
in occurrence data gathering.
For occurrence monitoring, the precision of the analyses is more
critical than in compliance monitoring. Unless the concentration of the
contaminant closely approaches the MCL, even relatively imprecise data
can be used to ensure the data user that the compound is not present at
a concentration above the MCL. However, the usefulness of occurrence
data is much more dependent upon the precision of the measurement. The
ability to perform meaningful statistical analysis, e.g., to determine
the percentage of waters in the United States that have compound X at
or above the minimum reporting level (MRL), or to determine whether
compound X occurs more frequently or at higher concentrations in one
type of water or geographical region of the country, is directly
dependent on the precision of the data.
The Agency has evaluated analytical methods developed by both EPA
and other voluntary consensus standards organizations that publish
analytical methods, such as Standard Methods and the American Society
for Testing and Materials. The Agency has not approved analytical
methods published only in analytical journals or methods that use
techniques that cannot routinely be used by all drinking water analysis
laboratories (e.g., acid, base/neutral fractionation, or packed column
gas chromatography). Because control of ``false negatives'' is
essential to the quality of the data collected under this proposed
regulation, documentation of the contaminants' stability under the
sample and extract holding conditions specified in the analytical
method were also evaluated.
For the compounds selected to be included in this regulation, the
following summary, Table 3, Status of Analytical Methods for Chemical
Contaminants on the UCM List, presents a brief assessment of methods
availability for each chemical contaminant. EPA requests public comment
on this assessment of methods availability.
Table 3.--Status of Analytical Methods for Chemical Contaminants on the UCM List
----------------------------------------------------------------------------------------------------------------
List 1--Organic chemical
contaminant CAS No. Analytical Methods Status of availability
----------------------------------------------------------------------------------------------------------------
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.
DCPA mono acid degradates....... 887-54-7 EPA 515.1 No method is available to measure
EPA 515.2 the mono and di acid forms
D5317-93 separately. All of the approved
AOAC 992.32 methods identify total mono and
di acid forms.
DCPA di acid degradates......... 2136-79-0 EPA 515.1 No method is available to measure
EPA 515.2 the mono and di acid forms
D5317-93 separately. All of the approved
AOAC 992.32 methods identify total mono and
di acid forms.
4,4'-DDE........................ 72-55-9 EPA 508 Methods are adequate for
EPA 508.1 monitoring.
EPA 525.2
D5812-96
AOAC 990.06
EPTC............................ 759-94-4 EPA 507 Methods are adequate for
EPA 525.2 monitoring.
D5475-93
AOAC 991.07
[[Page 23406]]
Molinate........................ 2212-67-1 EPA 507 Methods are adequate for
EPA 525.2 monitoring.
D5475-93
AOAC 991.07
MTBE............................ 1634-04-4 EPA 524.2 Methods are adequate for
D5790-95 monitoring.
SM6210D
Nitrobenzene.................... 98-95-3 EPA 524.2 Methods are adequate for
D5790-95 monitoring.
SM6210D
Terbacil........................ 5902-51-2 EPA 507 Methods are adequate for
EPA 525.2 monitoring.
D5475-93
AOAC 991.07
----------------------------------------------------------------------------------------------------------------
List 2--Organic chemical Availability of analytical
contaminant CAS No. methods Status of availability
----------------------------------------------------------------------------------------------------------------
1,2-diphenylhydrazine........... 122-66-7 In development............. Some methods evaluated but
inadequate. Priority for
analytical method development.
Anticipate that contaminant will
be added to 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.
Anticipate that contaminant will
be included in a new solid phase
extraction/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. Anticipate that
contaminant will be included in
a new solid phase extraction/GC/
MS method currently under
development.
2,4-dinitrophenol............... 51-28-5 In development............. Some methods evaluated but
inadequate. Anticipate that
contaminant will be included in
a new solid phase extraction/GC/
MS method currently under
development.
2-methy -phenol................. 95-48-7 In development............. Some methods evaluated but
inadequate. Anticipate that
contaminant will be included in
a new solid phase extraction/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
pesticides. within this group of compounds.
Analytical methods will be
determined for the targeted
contaminants.
Acetochlor...................... 34256-82-1 In development............. No adequate method available.
Anticipate that this compound
can be added to the scope of EPA
Method 525.2
Diazinon........................ 333-41-5 In development............. Diazinon is listed as an
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
preservation technique that
would permit adding this
compound to EPA Method 525.2.
Disulfoton...................... 298-04-4 In development............. Disulfoton is listed as an
contaminant in several EPA and
voluntary consensus standard
organization methods but it is
subject to rapid aqueous
degradation. Preservation
research currently be conducted
to develop 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. Anticipate 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 an
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
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. Anticipate that this
compound can be included in a
new SPE/HPLC/UV method currently
being developed.
Prometon........................ 1610-18-0 In development............. Prometon is listed as an
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.
[[Page 23407]]
Terbufos........................ 13071-79-9 In development............. Terbufos is listed as an
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.
----------------------------------------------------------------------------------------------------------------
(ii) Microbiological Analytical Methods
The discussion of data quality for chemical analytical methods will
also apply 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 sufficient information was available about methodologies
to consider regulating them, or another category where more research,
including research on detection methods and occurrence, was needed. At
the present time, Aeromonas is the only one of these microorganisms for
which more occurrence data are needed that also has an analytical
method that is likely to be sufficiently developed for monitoring in
time for implementation in the first round of Assessment Monitoring,
List 1, under this proposed program. Three other microorganisms have
methods available, but EPA is presently refining these methods. These
microorganisms may be candidates for the Screening Survey 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 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.
EPA is requesting public comment on the assessment of methods
availability and related issues presented below in Table 4.
Table 4.--Status of Analytical Methods for Microbiological Contaminants on the UCM List
--------------------------------------------------------------------------------------------------------------------------------------------------------
List 1--Microbiological contaminant Availability of analytical method Status of availability
--------------------------------------------------------------------------------------------------------------------------------------------------------
Aeromonas hydrophila..................................... Analytical method likely to be available for monitoring Current modification and evaluation
of a published membrane filtration
method (Havelaar et al., 1987)
indicates that this method will be
suitable for the monitoring
program.
List 3--Microbiological contaminant
Cyanobacteria (blue-green algae, other freshwater algae Methods available but not standardized................. Methods are available for counting
and their toxins). cyanobacteria but new, standardized
methods 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 standardized................. With care to control overgrowths,
echoviruses can be cultured on BGM
cells and detected by ICR method
but need methods such as
serological typing to distinguish
from other viruses. Cost of cell
culture assays plus serotyping can
be high. PCR methods, which are not
available, are subject to
interferences and do not
demonstrate infectivity.
Coxsackieviruses......................................... Methods available but not standardized................. Group B coxsackieviruses are easy to
grow in tissue culture but group A
coxsackieviruses are variable.
Culturable coxsackieviruses can be
detected with the ICR method but
serotyping is needed to distinguish
coxsackie from other viruses. Other
detection methods such as
immunoassay or PCR do not exist.
New, standardized methods are
needed.
Helicobacter pylori...................................... No method currently available.......................... Helicobacter pylori is difficult to
grow due to slow growth and the
need for a low oxygen environment.
No selective medium exist that will
discriminate H. pylori from
background bacteria. A culturable
method that demonstrates viability
is preferred. Methods are needed
for selective growth and
identification. IMS has been used
to concentrate Helicobacter pylori.
PCR methods have been used but are
not preferred due to interferences
and the inability to demonstrate
viability.
[[Page 23408]]
Microsporidia............................................ No method currently available.......................... No methods are available for the
monitoring of the two species of
human microspordia which have a
waterborne route of transmission
(Enterocytozoon bienuesi and
Septata intestinalis). Oocysts
could possibly be detected by
methods similar to those being
developed for Cryptosporidium.
Potential methods may utilize water
filtration, clean-up with
immunomagnetic separation (IMS) and
detection using microscopy with
either fluorescent antibody or gene
probe procedures. Due to the small
size of microsporidia, problems
could be encountered during
filtration.
Adenoviruses............................................. No method currently available.......................... Adenoviruses serotypes 1 to 39 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
because of interferences and
inability to demonstrate
infectivity.
Caliciviruses............................................ No method currently available.......................... No tissue culture methods exist for
the two caliciviruses on the CCL
(Norwalk and Snow Mountain). No
sensitive or fully developed
detection methods exist. PCR
methods are not preferred due to
interferences and the inability to
demonstrate infectivity.
--------------------------------------------------------------------------------------------------------------------------------------------------------
(d) Screening Methods
SDWA section 1445(i) requires EPA to review new analytical methods
that may be used for regulated contaminants screening and analysis.
After this review, EPA may approve such methods that are deemed ``more
accurate or cost-effective than established reference methods for use
in compliance monitoring.'' Section 1445(a)(2)(G) also allows States to
use screening methods approved by the Administrator for unregulated
contaminant monitoring. These methods are expected to provide
flexibility in compliance monitoring to water systems and laboratories
performing analysis on behalf on these systems. They are expected to be
``better and/or faster'' than existing analytical methods. EPA is
developing a framework for the use of screening procedures for
monitoring drinking water contaminants, and determining how the Agency
will approve or recommend screening procedures for specific
contaminants.
2. List of Contaminants To Be Monitored
(a) Proposed Monitoring List
Table 5, Unregulated Contaminant Monitoring List (Proposed),
presents EPA's proposal for the initial list of unregulated
contaminants for monitoring under section 1445(a)(2)(B)(i). The
monitoring program that EPA proposes 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
proposed 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 Survey; and List 3,
designated for Pre-screen Testing. Today's proposed regulation only
requires Assessment Monitoring for List 1 contaminants beginning on the
proposed effective date of January 1, 2001. The monitoring for
contaminants on Lists 2 and 3 will only be required after EPA
promulgates further rules.
EPA proposes requiring Assessment Monitoring for those contaminants
for which methods exist at the time this regulation is promulgated; as
a result, some contaminants from List 2 may move to List 1 if EPA
considers their methods reliable by promulgation of the final
regulation. Also, by future rulemaking, EPA plans to implement the
Screening Survey (List 2) monitoring in groups or batches 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 same method. EPA proposes to take a similar approach with the
contaminants in the Pre-Screen Testing (List 3) category. EPA plans to
require, through future rulemaking Pre-Screen Testing for contaminants
for which EPA needs to determine that new analytical methods can
measure their existence in locations 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. EPA is seeking comment on the approach of a three-
tiered monitoring program for unregulated contaminants and on the
proposed list of contaminants to be monitored.
In Table 5, List 1 contaminants, for Assessment Monitoring, are
organic chemicals and one microbiological contaminant 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 by promulgation of the final rule (August 1999). Monitoring
for these contaminants would be required under today's proposed UCMR.
These contaminants are in today's proposed rule, Sec. 141.40(a)(3),
Table 1, Unregulated Contaminant Monitoring List, List 1.
List 2 contaminants (all organic chemicals, at this time),
contaminants for the Screening Survey, are those for which EPA is
currently refining analytical methods. Development of these methods
should be sufficient for a Screening Survey to be conducted in the
first three years of the listing cycle, but may occur in the later
years of the cycle. If methods are available for any of these
contaminants before promulgation of the final rule, they will be added
to Assessment Monitoring, List 1. These contaminants are characterized
in today's proposed rule at Table 1, Unregulated Contaminant Monitoring
List, List 2.
List 3 contaminants (all microbiological contaminants, at this
time), contaminants 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 or Screening Survey required under implementation
[[Page 23409]]
of this regulation. Instead, these contaminants would be tested for in
Pre-Screen Testing. These contaminants are in today's proposed rule at
Sec. 141.40(a)(3) as Table 1, Unregulated Contaminant Monitoring List,
List 3.
The column headings of Table 5 include:
1--Chemical or microbiological contaminant: the name of the
contaminants to be analyzed.
2--CAS No. (Chemical Abstract Service Number): a unique number
identifying the chemical contaminants.
3--Analytical Methods: method numbers identifying the methods that
could be used to test the contaminants.
4--Minimum Reporting Level: the value and unit of measure at or above
which the concentration or density of the contaminant must be measured
using the Approved Analytical Methods.
5--Sampling Location: the locations within a PWS at which samples must
be collected.
6--Date Monitoring to Begin: The years during which the sampling and
testing are to occur for the indicated contaminant.
Table 5.--Unregulated Contaminant Monitoring List (Proposed)
--------------------------------------------------------------------------------------------------------------------------------------------------------
2--CAS 6--Date
1--Contaminant identification 3--Analytical methods 4--Minimum reporting 5--Sampling location monitoring to
No. level begin
--------------------------------------------------------------------------------------------------------------------------------------------------------
List 1--Assessment Monitoring: Organic Chemical Contaminants
--------------------------------------------------------------------------------------------------------------------------------------------------------
2,4-dinitrotoluene........... 121-14-2 EPA 525.2 <SUP>a</SUP> 2.4 ug/L <SUP>e</SUP> EPTDS <SUP>f</SUP> 2001-2003
2,6-dinitrotoluene........... 606-20-2 EPA 525.2 <SUP>a</SUP> 2.0 ug/L <SUP>e</SUP> EPTDS <SUP>f</SUP> 2001-2003
DCPA mono acid degradate..... 887-54-7 EPA 515.1 <SUP>a</SUP> 1.0 ug/L <SUP>e</SUP> EPTDS <SUP>f</SUP> 2001-2003
EPA 515.2 <SUP>a</SUP>
5317-93 <SUP>b</SUP>
AOAC 992.32 <SUP>c</SUP>
DCPA di acid degradate....... 2136-79-0 EPA 515.1 <SUP>a</SUP> 1.0 ug/L<SUP>e</SUP> EPTDS <SUP>f</SUP> 2001-2003
EPA 515.2 <SUP>a</SUP>
D5317-93 <SUP>b</SUP>
AOAC 992.32 <SUP>c</SUP>
4,4'-DDE..................... 72-55-9 EPA 508 <SUP>a</SUP> 0.75 ug/L<SUP>e</SUP> EPTDS <SUP>f</SUP> 2001-2003
EPA 508.1 <SUP>a</SUP>
EPA 525.2 <SUP>a</SUP>
D5812-96 <SUP>b</SUP>
EPTC......................... 759-94-4 EPA 507 <SUP>a</SUP> 1.2 ug/L <SUP>e</SUP> EPTDS <SUP>f</SUP> 2001-2003
Molinate..................... 2212-67-1 EPA 507 <SUP>a</SUP> 0.87 ug/L <SUP>e</SUP> EPTDS <SUP>f</SUP> 2001-2003
EPA 525.2 <SUP>a</SUP>
D5475-93 <SUP>b</SUP>
AOAC 991.07 <SUP>c</SUP>
MTBE......................... 1634-04-4 EPA 524.2 <SUP>a</SUP> 5.0 ug/L <SUP>g</SUP> EPTDS <SUP>f</SUP> 2001-2003
5790-95 <SUP>b</SUP>
SM6210D <SUP>d</SUP>
Nitrobenzene................. 98-95-3 EPA 524.2 <SUP>a</SUP> 12 ug/L <SUP>g</SUP> EPTDS <SUP>f</SUP> 2001-2003
D5790-95 <SUP>b</SUP>
SM6210D <SUP>d</SUP>
Terbacil..................... 5902-51-2 EPA 507 <SUP>a</SUP> 23 ug/L<SUP>e</SUP> EPTDS <SUP>f</SUP> 2001-2003
EPA 525.2 <SUP>a</SUP>
5475-93 <SUP>b</SUP>
AOAC 991.07 <SUP>c</SUP>
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List 1--Assessment Monitoring: Microbiological Contaminants
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Aeromonas Hydrophila......... Reserved <SUP>h</SUP> Membrane filter, in review 1 colony forming unit (1) Near end of 2001-2003
distribution line with
longest residence time;
(2) at a representative
site in the distribution
system
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CAS
Chemical contaminant identification Anticipated analytical methods Minimum reporting level <SUP>e</SUP> Sampling location
No.
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List 2--Screening Survey: Organic Chemical Contaminants (To Be Sampled After Notice of Analytical Methods Availability)
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1,2-diphenylhydrazine............. 122-66-7 EPA 525.2 <SUP>i</SUP> TBD <SUP>h</SUP> EPTDS <SUP>f</SUP>
2-methyl-phenol................... 95-48-7 SPE/GC/MS <SUP>l</SUP> TBD <SUP>h</SUP> EPTDS <SUP>f</SUP>
2,4-dichlorophenol................ 120-83-2 SPE/GC/MS <SUP>l</SUP> TBD <SUP>h</SUP> EPTDS <SUP>f</SUP>
2,4-dinitrophenol................. 51-28-5 SPE/GC/MS <SUP>l</SUP> TBD <SUP>h</SUP> EPTDS <SUP>f</SUP>
2,4,6-trichlorophenol............. 88-06-2 SPE/GC/MS <SUP>l</SUP> TBD <SUP>h</SUP> EPTDS <SUP>f</SUP>
Acetochlor........................ 34256-82-1 EPA 525.2 <SUP>i</SUP> TBD <SUP>h</SUP> EPTDS <SUP>f</SUP>
Alachlor ESA...................... ................. TBD <SUP>h</SUP> TBD <SUP>h</SUP> EPTDS <SUP>f</SUP>
Diazinon.......................... 333-41-5 EPA 525.2 <SUP>k</SUP> TBD <SUP>h</SUP> EPTDS <SUP>f</SUP>
TBD <SUP>h</SUP> EPTDS <SUP>f</SUP>
Disulfoton........................ 298-04-4 EPA 525.2 <SUP>k</SUP> .................................. .........................
[[Page 23410]]
Diuron............................ 330-54-1 SPE/HPLC/UV <SUP>j</SUP> TBD <SUP>h</SUP> EPTDS <SUP>f</SUP>
TBD <SUP>h</SUP> EPTDS <SUP>f</SUP>
Fonofos........................... 944-22-9 EPA 525.2 <SUP>i</SUP> .................................. .........................
Linuron........................... 330-55-2 SPE/HPLC/UV <SUP>j</SUP> TBD <SUP>h</SUP> EPTDS <SUP>f</SUP>
Prometon.......................... 1610-18-0 EPA 525.2 <SUP>k</SUP> TBD <SUP>h</SUP> EPTDS <SUP>f</SUP>
TBD <SUP>h</SUP> EPTDS <SUP>f</SUP>
Terbufos.......................... 13071-79-9 EPA 525.2 <SUP>k</SUP> .................................. .........................
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<SUP>a</SUP> The version of the EPA methods being approved will be dependent upon the status of the approval of new versions for compliance monitoring. If
appropriate regulations approving new versions of EPA compliance monitoring methods are completed prior to the promulgation of this regulation, the
following versions of the above methods will be approved. Methods for the Determination of Organic Compounds in Drinking Water--Supplement III, EPA-
600/R-95-131, August 1995. NTIS PB95-261616. Copies are also available from the National Technical Information Service (NTIS), U.S. Department of
Commerce, 5285 Port Royal Road, Springfield, Virginia 22161. The toll-free number is 800-553-6847.
If new regulations changing the versions of methods being approved for compliance monitoring are not completed prior to the promulgation of this
regulation, then the following versions of the EPA methods are being approved for monitoring under the Unregulated Contaminant Monitoring Rule.
Methods 507, 508, and 515.1 are in Methods for the Determination of Organic Compounds in Drinking Water, EPA-600/4-88-039, December 1988, Revised,
July 1991. Methods 515.2 and 524.2 are in Methods for the Determination of Organic Compounds in Drinking Water--Supplement II, EPA/600/R-92/129,
August 1992. These documents are available from the National Technical Information Service, (NTIS) U.S. Department of Commerce, 5285 Port Royal Road,
Springfield, Virginia 22161 (800) 553-6847. Methods 508.1 and 525.2 are available from US EPA NERL--Cincinnati, Cincinnati, Ohio 45268, (513) 569-
7586.
<SUP>b</SUP> Annual Book of ASTM Standards, 1996 and 1998, Vol. 11.02, American Society for Testing and Materials. Method D5812-96 is located in the Annual Book of
ASTM Standards, 1998, Vol. 11.02. Methods D5790-95, D5475-93, and D5317-93 are located in the Annual Book of ASTM Standards, 1996 and 1998, Vol 11.02.
Copies may be obtained from the American Society for Testing and Materials, 101 Barr Harbor Drive, West Conshohocken, PA 19428.
<SUP>c</SUP> Official Methods of Analysis of AOAC (Association of Official Analytical Chemist) International, Sixteenth Edition, 4th Revision, 1998, Volume I, AOAC
International, First Union National Bank Lockbox, PO Box 75198, Baltimore, MD 21275-5198. 1-800-379-2622.
<SUP>d</SUP> 18th and 19th editions of Standard Methods for the Examination of Water and Wastewater, 1992 and 1995, American Public Health Association; either
edition may be used. Copies may be obtained from the American Public Health Association, 1015 Fifteenth Street NW, Washington, DC 20005.
<SUP>e</SUP> Minimum Reporting Level determined by multiplying by 10 the least sensitive method's minimum detection limit (MDL=standard deviation times the
Student's T value for 99% confidence level with n-1 degrees of freedom), or when available, multiplying by 5 the least sensitive method's estimated
detection limit (where the EDL equals the concentration of compound yielding approximately a 5 to 1 signal to noise ratio or the calculated MDL,
whichever is greater).
<SUP>f</SUP> Entry Points to the Distribution System, After Treatment.
<SUP>g</SUP> Minimum Reporting Levels (MRL) for Volatile Organic Compounds (VOC) determined by multiplying either the published Method Detection Limit (MDL) or 0.5
<greek-m>g/L times 10, whichever is greater. The MDL of 0.5 ug/L (0.0005 mg/L) was selected to conform to VOC MDL requirements of 40 CFR
141.24(f)(17(E).
<SUP>h</SUP> To be Determined.
<SUP>i</SUP> Compound currently not listed as a contaminant in this method. Methods development currently being conducted in an attempt to add it to the scope of
this method.
<SUP>j</SUP> Methods development currently in progress to develop a solid phase extraction/high performance liquid chromatography/ultraviolet method for the
determination of this compound.
<SUP>k</SUP> Compound listed as being a contaminant using EPA Method 525.2; however, adequate sample preservation is not available. Preservation studies currently
being conducted to develop adequate sample preservation.
<SUP>l</SUP> Methods development currently in progress to develop a solid phase extraction/gas chromatography/mass spectrometery method for the determination of
this compound.
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Anticipated sampling
Microorganism Identification No. Anticipated analytical methods Minimum reporting level location
--------------------------------------------------------------------------------------------------------------------------------------------------------
List 3--Pre-screen Testing: Contaminants With Analytical Methods Not Anticipated (To Be Available by Regulation Implementation)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cyanobacteria (blue-green algae, Reserved <SUP>a</SUP>.............. TBD <SUP>a</SUP> TBD <SUP>a</SUP> TBD <SUP>a</SUP>
other freshwater algae and
their toxins).
Echoviruses..................... Reserved <SUP>a</SUP>.............. TBD <SUP>a</SUP> TBD <SUP>a</SUP> TBD <SUP>a</SUP>
Coxsackieviruses................ Reserved <SUP>a</SUP>.............. TBD <SUP>a</SUP> TBD <SUP>a</SUP> TBD <SUP>a</SUP>
Helicobacter pylori............. Reserved <SUP>a</SUP>.............. TBD <SUP>a</SUP> TBD <SUP>a</SUP> TBD <SUP>a</SUP>
Microsporidia................... Reserved <SUP>a</SUP>.............. TBD <SUP>a</SUP> TBD <SUP>a</SUP> TBD <SUP>a</SUP>
Caliciviruses................... Reserved <SUP>a</SUP>.............. TBD <SUP>a</SUP> TBD <SUP>a</SUP> TBD <SUP>a</SUP>
Adenoviruses.................... Reserved <SUP>a</SUP>.............. TBD <SUP>a</SUP> TBD <SUP>a</SUP> TBD <SUP>a</SUP>
--------------------------------------------------------------------------------------------------------------------------------------------------------
<SUP>a</SUP>=To Be Determined.
Tables 3 and 4, in III.A.1.(c), Analytical Methods Applicable to
the Monitoring 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 Monitoring List
and program, 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 Monitoring List
Thirty-two contaminants are on the UCM List, as proposed. SDWA
Section 1445 (a)(2)(B)(i) indicates that the List shall not have more
than 30 contaminants required to be monitored by public water systems.
EPA interprets this to mean that the List may contain more than 30
contaminants, as long as monitoring is not required for more than 30
contaminants during the five-year listing cycle. EPA proposes that the
32 contaminants identified in the CCL Occurrence Priorities remain on
the UCM List, with monitoring required for no more than 30 contaminants
in any five-year UCM cycle. Furthermore, EPA proposes that future UCM
Lists may include additional contaminants beyond 30, but the UCMR
Program would only
[[Page 23411]]
require monitoring for up to 30 contaminants during any listing cycle.
The contaminants beyond 30 are ones for which PWSs might
voluntarily provide data if they monitored for them for their own
purposes. These additionally identified contaminants might also be ones
for which PWSs might send EPA samples to be tested and analyzed (by
EPA) if the Agency is developing or recently developed a provisional
analytical method for them. EPA is preparing a guidance document
specifying the procedures for voluntary submission of such data in the
future to the National Contaminant Occurrence Database (NCOD). EPA
requests public comment on maintaining a UCM List of more than 30
contaminants, but limiting PWS monitoring to 30 contaminants in any
five-year UCMR listing cycle.
(c) Modifying the Monitoring List through the Governors' Petition
Section 1445(a)(2)(B)(ii) of SDWA provides that the Administrator
shall include in the UCM List each contaminant recommended in a
petition signed by the Governor of each of seven or more States, unless
the Administrator d |
