[Code of Federal Regulations]
[Title 40, Volume 22]
[Revised as of July 1, 2005]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR141.23]
[Page 362-372]
TITLE 40--PROTECTION OF ENVIRONMENT
CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
PART 141_NATIONAL PRIMARY DRINKING WATER REGULATIONS--Table of Contents
Subpart C_Monitoring and Analytical Requirements
Sec. 141.23 Inorganic chemical sampling and analytical requirements.
Community water systems shall conduct monitoring to determine
compliance with the maximum contaminant levels specified in Sec. 141.62
in accordance with this section. Non-transient, non-community water
systems shall conduct monitoring to determine compliance with the
maximum contaminant levels specified in Sec. 141.62 in accordance with
this section. Transient, non-community water systems shall conduct
monitoring to determine compliance with the nitrate and nitrite maximum
contaminant levels in Sec. Sec. 141.11 and 141.62 (as appropriate) in
accordance with this section.
(a) Monitoring shall be conducted as follows:
(1) Groundwater systems shall take a minimum of one sample at every
entry point to the distribution system which is representative of each
well after treatment (hereafter called a sampling point) beginning in
the initial compliance period. The system shall take each sample at the
same sampling point unless conditions make another sampling point more
representative of each source or treatment plant.
(2) Surface water systems shall take a minimum of one sample at
every entry point to the distribution system after any application of
treatment or in the distribution system at a point which is
representative of each source after treatment (hereafter called a
sampling point) beginning in the initial compliance period. The system
shall take each sample at the same sampling point unless conditions make
another sampling point more representative of each source or treatment
plant.
Note: For purposes of this paragraph, surface water systems include
systems with a combination of surface and ground sources.
(3) If a system draws water from more than one source and the
sources are combined before distribution, the system must sample at an
entry point to the distribution system during periods of normal
operating conditions (i.e., when water is representative of all sources
being used).
(4) The State may reduce the total number of samples which must be
analyzed by allowing the use of compositing. Composite samples from a
maximum of five samples are allowed, provided that the detection limit
of the method used for analysis is less than one-fifth of the MCL.
Compositing of samples must be done in the laboratory.
(i) If the concentration in the composite sample is greater than or
equal to one-fifth of the MCL of any inorganic chemical, then a follow-
up sample must be taken within 14 days at each sampling point included
in the composite. These samples must be analyzed for the contaminants
which exceeded one-fifth of the MCL in the composite sample. Detection
limits for each analytical method and MCLs for each inorganic
contaminant are the following:
Detection Limits for Inorganic Contaminants
------------------------------------------------------------------------
Detection
Contaminant MCL (mg/l) Methodology limit (mg/l)
------------------------------------------------------------------------
Antimony.................. 0.006...... Atomic 0.003
Absorption;
Furnace.
Atomic 0.0008 \5\
Absorption;
Platform.
ICP-Mass 0.0004
Spectrometry.
Hydride-Atomic 0.001
Absorption.
Arsenic................... 0.010 \6\.. Atomic 0.001
Absorption;
Furnace.
Atomic 0.0005 \7\
Absorption;
Platform--Stabi
lized
Temperature.
[[Page 363]]
Atomic 0.001
Absorption;
Gaseous Hydride.
ICP-Mass 0.0014 \8\
Spectrometry.
Asbestos.................. 7 MFL \1\.. Transmission 0.01 MFL
Electron
Microscopy.
Barium.................... 2.......... Atomic 0.002
Absorption;
furnace
technique.
Atomic 0.1
Absorption;
direct
aspiration.
Inductively 0.002 (0.001)
Coupled Plasma.
Beryllium................. 0.004...... Atomic 0.0002
Absorption;
Furnace.
Atomic 0.00002 \5\
Absorption;
Platform.
Inductively 0.0003
Coupled Plasma
\2\.
ICP-Mass 0.0003
Spectrometry.
Cadmium................... 0.005...... Atomic 0.0001
Absorption;
furnace
technique.
Inductively 0.001
Coupled Plasma.
Chromium.................. 0.1........ Atomic 0.001
Absorption;
furnace
technique.
Inductively 0.007 (0.001)
Coupled Plasma.
Cyanide................... 0.2........ Distillation, 0.02
Spectrophotomet
ric \3\.
........... Distillation, 0.005
Automated,
Spectrophotomet
ric \3\.
........... Distillation, 0.02
Amenable,
Spectrophotomet
ric \4\.
........... Distillation, 0.05
Selective
Electrode \3\.
........... UV, 0.0005
Distillation,
Spectrophotomet
ric.
........... Distillation, 0.0006
Spectrophotomet
ric.
Mercury................... 0.002...... Manual Cold 0.0002
Vapor Technique.
Automated Cold 0.0002
Vapor Technique.
Nickel.................... xl......... Atomic 0.001
Absorption;
Furnace.
Atomic 0.0006 \5\
Absorption;
Platform.
Inductively 0.005
Coupled Plasma
\2\.
ICP-Mass 0.0005
Spectrometry.
Nitrate................... 10 (as N).. Manual Cadmium 0.01
Reduction.
Automated 0.01
Hydrazine
Reduction.
Automated 0.05
Cadmium
Reduction.
Ion Selective 1
Electrode.
Ion 0.01
Chromatography.
Nitrite................... 1 (as N)... Spectrophotometr 0.01
ic.
Automated 0.05
Cadmium
Reduction.
Manual Cadmium 0.01
Reduction.
Ion 0.004
Chromatography.
Selenium.................. 0.05....... Atomic 0.002
Absorption;
furnace.
Atomic 0.002
Absorption;
gaseous hydride.
Thallium.................. 0.002...... Atomic 0.001
Absorption;
Furnace.
Atomic 0.0007 \5\
Absorption;
Platform.
ICP-Mass 0.0003
Spectrometry.
------------------------------------------------------------------------
\1\ MFL = million fibers per liter 10 [micro]m.
\2\ Using a 2X preconcentration step as noted in Method 200.7. Lower
MDLs may be achieved when using a 4X preconcentration.
\3\ Screening method for total cyanides.
\4\ Measures ``free'' cyanides.
\5\ Lower MDLs are reported using stabilized temperature graphite
furnace atomic absorption.
\6\ The value for arsenic is effective January 23, 2006. Unit then, the
MCL is 0.05 mg/L.
\7\ The MDL reported for EPA method 200.9 (Atomic Absorption; Platform--
Stablized Temperature) was determined using a 2x concentration step
during sample digestion. The MDL determined for samples analyzed using
direct analyses (i.e., no sample digestion) will be higher. Using
multiple depositions, EPA 200.9 is capable of obtaining MDL of 0.0001
mg/L.
\8\ Using selective ion monitoring, EPA Method 200.8 (ICP-MS) is capable
of obtaining a MDL of 0.0001 mg/L.
(ii) If the population served by the system is 3,300
persons, then composit ing may only be permitted by the State at
sampling points within a single system. In systems serving <=3,300
persons, the State may permit compositing among different systems
provided the 5-sample limit is maintained.
(iii) If duplicates of the original sample taken from each sampling
point used in the composite sample are available, the system may use
these instead of resampling. The duplicates must be analyzed and the
results reported to the State within 14 days after completing analysis
of the composite sample, provided the holding time of the sample is not
exceeded.
(5) The frequency of monitoring for asbestos shall be in accordance
with paragraph (b) of this section: the frequency of monitoring for
antimony, arsenic, barium, beryllium, cadmium, chromium, cyanide,
fluoride, mercury, nickel, selenium and thallium shall be in accordance
with paragraph (c) of
[[Page 364]]
this section; the frequency of monitoring for nitrate shall be in
accordance with paragraph (d) of this section; and the frequency of
monitoring for nitrite shall be in accordance with paragraph (e) of this
section.
(b) The frequency of monitoring conducted to determine compliance
with the maximum contaminant level for asbestos specified in Sec.
141.62(b) shall be conducted as follows:
(1) Each community and non-transient, non-community water system is
required to monitor for asbestos during the first three-year compliance
period of each nine-year compliance cycle beginning in the compliance
period starting January 1, 1993.
(2) If the system believes it is not vulnerable to either asbestos
contamination in its source water or due to corrosion of asbestos-cement
pipe, or both, it may apply to the State for a waiver of the monitoring
requirement in paragraph (b)(1) of this section. If the State grants the
waiver, the system is not required to monitor.
(3) The State may grant a waiver based on a consideration of the
following factors:
(i) Potential asbestos contamination of the water source, and
(ii) The use of asbestos-cement pipe for finished water distribution
and the corrosive nature of the water.
(4) A waiver remains in effect until the completion of the three-
year compliance period. Systems not receiving a waiver must monitor in
accordance with the provisions of paragraph (b)(1) of this section.
(5) A system vulnerable to asbestos contamination due solely to
corrosion of asbestos-cement pipe shall take one sample at a tap served
by asbestos-cement pipe and under conditions where asbestos
contamination is most likely to occur.
(6) A system vulnerable to asbestos contamination due solely to
source water shall monitor in accordance with the provision of paragraph
(a) of this section.
(7) A system vulnerable to asbestos contamination due both to its
source water supply and corrosion of asbestos-cement pipe shall take one
sample at a tap served by asbestos-cement pipe and under conditions
where asbestos contamination is most likely to occur.
(8) A system which exceeds the maximum contaminant levels as
determined in Sec. 141.23(i) of this section shall monitor quarterly
beginning in the next quarter after the violation occurred.
(9) The State may decrease the quarterly monitoring requirement to
the frequency specified in paragraph (b)(1) of this section pro vided
the State has determined that the sys tem is reliably and consistently
below the maximum contaminant level. In no case can a State make this de
term i na tion unless a groundwater system takes a minimum of two
quarterly samples and a surface (or combined surface/ground) water
system takes a minimum of four quarterly samples.
(10) If monitoring data collected after January 1, 1990 are
generally consistent with the requirements of Sec. 141.23(b), then the
State may allow systems to use that data to satisfy the monitoring
requirement for the initial compliance period beginning January 1, 1993.
(c) The frequency of monitoring conducted to determine compliance
with the maximum contaminant levels in Sec. 141.62 for antimony,
arsenic, barium, beryllium, cadmium, chromium, cyanide, fluoride,
mercury, nickel, selenium and thallium shall be as follows:
(1) Groundwater systems shall take one sample at each sampling point
during each compliance period. Surface water systems (or combined
surface/ground) shall take one sample annually at each sampling point.
(2) The system may apply to the State for a waiver from the
monitoring frequencies specified in paragraph (c)(1) of this section.
States may grant a public water system a waiver for monitoring of
cyanide, provided that the State determines that the system is not
vulnerable due to lack of any industrial source of cyanide.
(3) A condition of the waiver shall require that a system shall take
a minimum of one sample while the waiver is effective. The term during
which the waiver is effective shall not exceed one compliance cycle
(i.e., nine years).
[[Page 365]]
(4) The State may grant a waiver provided surface water systems have
monitored annually for at least three years and groundwater systems have
conducted a minimum of three rounds of monitoring. (At least one sample
shall have been taken since January 1, 1990). Both surface and
groundwater systems shall demonstrate that all previous analytical
results were less than the maximum contaminant level. Systems that use a
new water source are not eligible for a waiver until three rounds of
monitoring from the new source have been completed.
(5) In determining the appropriate reduced monitoring frequency, the
State shall consider:
(i) Reported concentrations from all previous monitoring;
(ii) The degree of variation in reported concentrations; and
(iii) Other factors which may affect contaminant concentrations such
as changes in groundwater pumping rates, changes in the system's
configuration, changes in the system's operating procedures, or changes
in stream flows or characteristics.
(6) A decision by the State to grant a waiver shall be made in
writing and shall set forth the basis for the determination. The
determination may be initiated by the State or upon an application by
the public water system. The public water system shall specify the basis
for its request. The State shall review and, where appropriate, revise
its determination of the appropriate monitoring frequency when the
system submits new monitoring data or when other data relevant to the
system's appropriate monitoring frequency become available.
(7) Systems which exceed the maximum contaminant levels as
calculated in Sec. 141.23(i) of this section shall monitor quarterly
beginning in the next quarter after the violation occurred.
(8) The State may decrease the quarterly monitoring requirement to
the frequencies specified in paragraphs (c)(1) and (c)(2) of this
section provided it has determined that the system is reliably and
consistently below the maximum contaminant level. In no case can a State
make this determination unless a groundwater system takes a minimum of
two quarterly samples and a surface water system takes a minimum of four
quarterly samples.
(9) All new systems or systems that use a new source of water that
begin operation after January 22, 2004 must demonstrate compliance with
the MCL within a period of time specified by the State. The system must
also comply with the initial sampling frequencies specified by the State
to ensure a system can demonstrate compliance with the MCL. Routine and
increased monitoring frequencies shall be conducted in accordance with
the requirements in this section.
(d) All public water systems (community; non-transient, non-
community; and transient, non-community systems) shall monitor to
determine compliance with the maximum contaminant level for nitrate in
Sec. 141.62.
(1) Community and non-transient, non-community water systems served
by groundwater systems shall monitor annually beginning January 1, 1993;
systems served by surface water shall monitor quarterly beginning
January 1, 1993.
(2) For community and non-transient, non-community water systems,
the repeat monitoring frequency for groundwater systems shall be
quarterly for at least one year following any one sample in which the
concentration is =50 percent of the MCL. The State may allow
a groundwater system to reduce the sampling frequency to annually after
four consecutive quarterly samples are reliably and consistently less
than the MCL.
(3) For community and non-transient, non-community water systems,
the State may allow a surface water system to reduce the sampling
frequency to annually if all analytical results from four consecutive
quarters are <50 percent of the MCL. A surface water system shall return
to quarterly monitoring if any one sample is =50 percent of
the MCL.
(4) Each transient non-community water system shall monitor annually
beginning January 1, 1993.
[[Page 366]]
(5) After the initial round of quarterly sampling is completed, each
community and non-transient non-community system which is monitoring
annually shall take subsequent samples during the quarter(s) which
previously resulted in the highest analytical result.
(e) All public water systems (community; non-transient, non-
community; and transient, non-community systems) shall monitor to
determine compliance with the maximum contaminant level for nitrite in
Sec. 141.62(b).
(1) All public water systems shall take one sample at each sampling
point in the compliance period beginning January 1, 1993 and ending
December 31, 1995.
(2) After the initial sample, systems where an analytical result for
nitrite is <50 percent of the MCL shall monitor at the frequency
specified by the State.
(3) For community, non-transient, non-community, and transient non-
community water systems, the repeat monitoring frequency for any water
system shall be quarterly for at least one year following any one sample
in which the concentration is [gteqt]50 percent of the MCL. The State
may allow a system to reduce the sampling frequency to annually after
determining the system is reliably and consistently less than the MCL.
(4) Systems which are monitoring annually shall take each subsequent
sample during the quarter(s) which previously resulted in the highest
analytical result.
(f) Confirmation samples:
(1) Where the results of sampling for antimony, arsenic, asbestos,
barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury,
nickel, selenium or thallium indicate an exceedance of the maximum
contaminant level, the State may require that one additional sample be
collected as soon as possible after the initial sample was taken (but
not to exceed two weeks) at the same sampling point.
(2) Where nitrate or nitrite sampling results indicate an exceedance
of the maximum contaminant level, the system shall take a confirmation
sample within 24 hours of the system's receipt of notification of the
analytical results of the first sample. Systems unable to comply with
the 24-hour sampling requirement must immediately notify persons served
by the public water system in accordance with Sec. 141.202 and meet
other Tier 1 public notification requirements under Subpart Q of this
part. Systems exercising this option must take and analyze a
confirmation sample within two weeks of notification of the analytical
results of the first sample.
(3) If a State-required confirmation sample is taken for any
contaminant, then the results of the initial and confirmation sample
shall be aver aged. The resulting average shall be used to determine the
system's compliance in accordance with paragraph (i) of this section.
States have the discretion to delete results of obvious sampling errors.
(g) The State may require more frequent monitoring than specified in
paragraphs (b), (c), (d) and (e) of this section or may require
confirmation samples for positive and negative results at its
discretion.
(h) Systems may apply to the State to conduct more frequent
monitoring than the minimum monitoring frequencies specified in this
section.
(i) Compliance with Sec. Sec. 141.11 or 141.62(b) (as appropriate)
shall be determined based on the analytical result(s) obtained at each
sampling point.
(1) For systems which are conducting monitoring at a frequency
greater than annual, compliance with the maximum contaminant levels for
antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium,
cyanide, fluoride, mercury, nickel, selenium or thallium is determined
by a running annual average at any sampling point. If the average at any
sampling point is greater than the MCL, then the system is out of
compliance. If any one sample would cause the annual average to be
exceeded, then the system is out of compliance immediately. Any sample
below the method detection limit shall be calculated at zero for the
purpose of determining the annual average. If a system fails to collect
the required number of samples, compliance (average concentration) will
be based on the total number of samples collected.
[[Page 367]]
(2) For systems which are monitoring annually, or less frequently,
the system is out of compliance with the maximum contaminant levels for
antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium,
cyanide, fluoride, mercury, nickel, selenium or thallium if the level of
a contaminant is greater than the MCL. If confirmation samples are
required by the State, the determination of compliance will be based on
the annual average of the initial MCL exceedance and any State-required
confirmation samples. If a system fails to collect the required number
of samples, compliance (average concentration) will be based on the
total number of samples collected.
(3) Compliance with the maximum contaminant levels for nitrate and
nitrate is determined based on one sample if the levels of these
contaminants are below the MCLs. If the levels of nitrate and/or nitrite
exceed the MCLs in the initial sample, a confirmation sample is required
in accordance with paragraph (f)(2) of this section, and compliance
shall be determined based on the average of the initial and confirmation
samples.
(4) Arsenic sampling results will be reported to the nearest 0.001
mg/L.
(j) Each public water system shall monitor at the time designated by
the State during each compliance period.
(k) Inorganic analysis:
(1) Analysis for the following contaminants shall be conducted in
accordance with the methods in the following table, or their equivalent
as determined by EPA. Criteria for analyzing arsenic, barium, beryllium,
cadmium, calcium, chromium, copper, lead, nickel, selenium, sodium, and
thallium with digestion or directly without digestion, and other
analytical test procedures are contained in Technical Notes on Drinking
Water Methods, EPA-600/R-94-173, October 1994. This document also
contains approved analytical test methods which remain available for
compliance monitoring until July 1, 1996. These methods will not be
available for use after July 1, 1996. This document is available from
the National Technical Information Service, NTIS PB95-104766, U.S.
Department of Commerce, 5285 Port Royal Road, Springfield, Virginia
22161. The toll-free number is 800-553-6847.
----------------------------------------------------------------------------------------------------------------
Contaminant and methodology SM \4\ (18th, SM \4\ (20th
\13\ EPA ASTM \3\ 19th ed.) ed.) Other
----------------------------------------------------------------------------------------------------------------
1. Alkalinity:
Titrimetric................. .............. D1067--92B.... 2320 B........ 2320 B
Electrometric titration..... .............. .............. .............. .............. I-1030-85 \5\
2. Antimony:
Inductively Coupled Plasma 200.8 \2\.....
(ICP)--Mass Spectrometry.
Hydride-Atomic Absorption... .............. D3697-92
Atomic Absorption; Platform. 200.9 \2\
Atomic Absorption; Furnace.. .............. .............. 3113 B
3. Arsenic: \14\
Inductively Coupled Plasma 200.7 \2\..... .............. 3120 B........ 3120 B
\15\.
ICP-Mass Spectrometry....... 200.8 \2\.....
Atomic Absorption; Platform. 200.9 \2\.....
Atomic Absorption; Furnace.. .............. D2972-97C..... 3113 B
Hydride Atomic Absorption... .............. D2972-97B..... 3114 B
4. Asbestos:
Transmission Electron 100.1 \9\.....
Microscopy.
Transmission Electron 100.2 \10\....
Microscopy.
5. Barium:
Inductively Coupled Plasma.. 200.7 \2\..... .............. 3120 B........ 3120 B
ICP-Mass Spectrometry....... 200.8 \2\.....
Atomic Absorption; Direct... .............. .............. 3111 D
Atomic Absorption; Furnace.. .............. .............. 3113 B
6. Beryllium:
Inductively Coupled Plasma.. 200.7 \2\..... .............. 3120 B........ 3120 B
ICP-Mass Spectrometry....... 200.8 \2\.....
Atomic Absorption; Platform. 200.9 \2\.....
Atomic Absorption; Furnace.. .............. D3645--97B.... 3113 B
[[Page 368]]
7. Cadmium:
Inductively Coupled Plasma.. 200.7 \2\
ICP-Mass Spectrometry....... 200.8 \2\
Atomic Absorption; Platform. 200.9 \2\
Atomic Absorption; Furnace.. .............. .............. 3113 B........
8. Calcium:
EDTA titrimetric............ .............. D511--93A..... 3500-Ca D..... 3500-Ca B.....
Atomic Absorption; Direct .............. D511--93B..... 3111 B........
Aspiration.
Inductively Coupled Plasma.. 200.7 \2\..... .............. 3120 B........ 3120 B........
9. Chromium:
Inductively Coupled Plasma.. 200.7 \2\..... .............. 3120 B........ 3120 B........
ICP-Mass Spectrometry....... 200.8 \2\.....
Atomic Absorption; Platform. 200.9 \2\.....
Atomic Absorption; Furnace.. .............. .............. 3113 B........
10. Copper:
Atomic Absorption; Furnace.. .............. D1688-95C..... 3113 B........
Atomic Absorption; Direct .............. D1688-95A..... 3111 B........
Aspiration.
Inductively Coupled Plasma.. 200.7 \2\..... .............. 3120 B........ 3120 B........
ICP-Mass spectrometry....... 200.8 \2\.....
Atomic Absorption; Platform. 200.9 \2\.....
11. Conductivity:
Conductance................. .............. D1125-95A..... 2510 B........ 2510 B........
12. Cyanide:
Manual Distillation followed .............. D2036-98A..... 4500-CN- C.... 4500-CN- C....
by.
Spectrophotometric .............. D2036-98A..... 4500-CN- E.... 4500-CN- E.... I-3300-85 \5\
Manual.
Spectrophotometric Semi- 335.4 \6\.....
automated.
Spectrophotometric, .............. D2036-98B..... 4500-CN- G.... 4500-CN- G....
Amenable.
Selective Electrode......... .............. .............. 4500-CN- F.... 4500-CN- F....
UV/Distillation/ .............. .............. .............. .............. Kelada 01 \17\
Spectrophotometric.
Distillation/ .............. .............. .............. .............. QuikChem 10-
Spectrophotometric. 204-00-1-X
\18\
13. Fluoride:
Ion Chromatography.......... 300.0 \6\..... D4327-97...... 4110 B........ 4110 B........
Manual Distill.; Color. .............. .............. 4500-F- B,D... 4500-F- B,D... ..............
SPADNS.
Manual Electrode............ .............. D1179-93B..... 4500-F- C..... 4500-F- C..... ..............
Automated Electrode......... .............. .............. .............. .............. 380-75WE \11\
Automated Alizarin.......... .............. .............. 4500-F- E..... 4500-F- E..... 29-71W \11\
14. Lead:
Atomic Absorption; Furnace.. .............. D3559-96D..... 3113 B........
ICP-Mass spectrometry....... 200.8 \2\.....
Atomic Absorption; Platform. 200.9 \2\.....
Differential Pulse Anodic .............. .............. .............. .............. Method 1001
Stripping Voltammetry. \16\
15. Magnesium:
Atomic Absorption........... .............. D511-93 B..... 3111 B........
ICP......................... 200.7 \2\..... .............. 3120 B........ 3120 B........
Complexation Titrimetric .............. D511-93 A..... 3500-Mg E..... 3500-Mg B.....
Methods.
16. Mercury:
Manual, Cold Vapor.......... 245.1 \2\..... D3223-97...... 3112 B........
Automated, Cold Vapor....... 245.2 \1\.....
ICP-Mass Spectrometry....... 200.8 \2\.....
17. Nickel:
Inductively Coupled Plasma.. 200.7 \2\..... .............. 3120 B........ 3120 B........
ICP-Mass Spectrometry....... 200.8 \2\.....
[[Page 369]]
Atomic Absorption; Platform. 200.9 \2\.....
Atomic Absorption; Direct... .............. .............. 3111 B........
Atomic Absorption; Furnace.. .............. .............. 3113 B........
18. Nitrate:
Ion Chromatography.......... 300.0 \6\..... D4327-97...... 4110 B........ 4110 B........ B-1011 \8\
Automated Cadmium Reduction. 353.2 \6\..... D3867-90A..... 4500-NO3- F... 4500-NO3- F...
Ion Selective Electrode..... .............. .............. 4500-NO3- D... 4500-NO3- D... 601 \7\
Manual Cadmium Reduction.... .............. D3867-90B..... 4500-NO3- E... 4500-NO3- E...
19. Nitrite:
Ion Chromatography.......... 300.0 \6\..... D4327-97...... 4110 B........ 4110 B........ B-1011 \8\
Automated Cadmium Reduction. 353.2 \6\..... D3867-90A..... 4500-NO3-..... 4500-NO3- F...
Manual Cadmium Reduction.... .............. D3867-90B..... 4500-NO3- E... 4500-NO3- E... ..............
Spectrophotometric.......... .............. .............. 4500-NO2- B... 4500- NO2- B..
20. Ortho-phosphate: \12\
Colorimetric, Automated, 365.1 \6\..... .............. 4500-P F...... 4500-P F......
Ascorbic Acid.
Colorimetric, ascorbic acid, .............. D515-88A...... 4500-P E...... 4500-P E......
single reagent.
Colorimetric .............. .............. .............. .............. I-1601-85 \5\
Phosphomolybdate;.
Automated-segmented .............. .............. .............. .............. I-2601-90 \5\
Flow;.
Automated Discrete...... .............. .............. .............. .............. I-2598-85 \5\
Ion Chromatography.......... 300.0 \6\..... D4327-97...... 4110 B........ 4110 B........
21. pH:
Electrometric............... 150.1 \1\..... D1293-95...... 4500-H+ B..... 4500-H+ B.....
150.2 \1\.....
22. Selenium:
Hydride-Atomic Absorption... .............. D3859-98A..... 3114 B........
ICP-Mass Spectrometry....... 200.8 \2\.....
Atomic Absorption; Platform. 200.9 \2\.....
Atomic Absorption; Furnace.. .............. D3859-98B..... 3113 B........
23. Silica:
Colorimetric, Molybdate .............. .............. .............. .............. I-1700-85 \5\
Blue;.
Automated-segmented Flow .............. .............. .............. .............. I-2700-85 \5\
Colorimetric................ .............. D859-95.......
Molybdosilicate............. .............. .............. 4500-Si D..... 4500-SiO2 C...
Heteropoly Blue............. .............. .............. 4500-Si E..... 4500-SiO2 D...
Automated for Molybdate- .............. .............. 4500-Si F..... 4500-SiO2 E...
reactive Silica.
Inductively Coupled Plasma.. 200.7 \2\..... .............. 3120 B........ 3120 B........
24. Sodium:
Inductively Coupled Plasma.. 200.7 \2\.....
Atomic Absorption; Direct .............. .............. 3111 B........
Aspiration.
25. Temperature:
Thermometric................ .............. .............. 2550.......... 2550..........
26. Thallium:
ICP-Mass Spectrometry....... 200.8 \2\.....
Atomic Absorption; Platform. 200.9 \2\.....
----------------------------------------------------------------------------------------------------------------
The procedures shall be done in accordance with the documents listed below. The incorporation by reference of
the following documents listed in footnotes 1-11 and 16 was approved by the Director of the Federal Register
in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the documents may be obtained from the sources
listed below. Information regarding obtaining these documents can be obtained from the Safe Drinking Water
Hotline at 800-426-4791. Documents may be inspected at EPA'sDrinking Water Docket, EPA West, 1301 Constitution
Avenue, NW, Room B135, Washington, DC (Telephone: 202-566-2426); or at the National Archives and Records
Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go
to: http://www.archives.gov/federal--register/code--of--federal--regulations/ibr--locations.html.
\1\ ``Methods for Chemical Analysis of Water and Wastes'', EPA/600/4-79/020, March 1983. Available at NTIS, PB84-
128677.
\2\ ``Methods for the Determination of Metals in Environmental Samples--Supplement I'', EPA/600/R-94/111, May
1994. Available at NTIS, PB95-125472.
[[Page 370]]
\3\ Annual Book of ASTM Standards, 1994, 1996, or 1999, Vols. 11.01 and 11.02, ASTM International; any year
containing the cited version of the method may be used. The previous versions of D1688-95A, D1688-95C
(copper), D3559-95D (lead), D1293-95 (pH), D1125-91A (conductivity) and D859-94 (silica) are also approved.
These previous versions D1688-90A, C; D3559-90D, D1293-84, D1125-91A and D859-88, respectively are located in
the Annual Book of ASTM Standards, 1994, Vol. 11.01. Copies may be obtained from ASTM International, 100 Barr
Harbor Drive, West Conshohocken, PA 19428.
\4\ Standard Methods for the Examination of Water and Wastewater, 18th edition (1992), 19th edition (1995), or
20th edition (1998). American Public Health Association, 1015 Fifteenth Street, NW, Washington, DC 20005. The
cited methods published in any of these three editions may be used, except that the versions of 3111 B, 3111
D, 3113 B and 3114 B in the 20th edition may not be used.
\5\ Method I-2601-90, Methods for Analysis by the U.S. Geological Survey National Water Quality Laboratory--
Determination of Inorganic and Organic Constituents in Water and Fluvial Sediment, Open File Report 93-125,
1993; For Methods I-1030-85; I-1601-85; I-1700-85; I-2598-85; I-2700-85; and I-3300-85 See Techniques of Water
Resources Investigation of the U.S. Geological Survey, Book 5, Chapter A-1, 3rd ed., 1989; Available from
Information Services, U.S. Geological Survey, Federal Center, Box 25286, Denver, CO 80225-0425.
\6\ ``Methods for the Determination of Inorganic Substances in Environmental Samples'', EPA/600/R-93/100, August
1993. Available at NTIS, PB94-120821.
\7\ The procedure shall be done in accordance with the Technical Bulletin 601 ``Standard Method of Test for
Nitrate in Drinking Water'', July 1994, PN 221890-001, Analytical Technology, Inc. Copies may be obtained from
ATI Orion, 529 Main Street, Boston, MA 02129.
\8\ Method B-1011, ``Waters Test Method for Determination of Nitrite/Nitrate in Water Using Single Column Ion
Chromatography,'' August 1987. Copies may be obtained from Waters Corporation, Technical Services Division, 34
Maple Street, Milford, MA 01757.
\9\ Method 100.1, ``Analytical Method For Determination of Asbestos Fibers in Water'', EPA/600/4-83/043, EPA,
September 1983. Available at NTIS, PB83-260471.
\10\ Method 100.2, ``Determination of Asbestos Structure Over 10 [micro]m In Length In Drinking Water'', EPA/600/
R-94/134, June 1994. Available at NTIS, PB94-201902.
\11\ Industrial Method No. 129-71W, ``Fluoride in Water and Wastewater'', December 1972, and Method No. 380-
75WE, ``Fluoride in Water and Wastewater'', February 1976, Technicon Industrial Systems. Copies may be
obtained from Bran & Luebbe, 1025 Busch Parkway, Buffalo Grove, IL 60089.
\12\ Unfiltered, no digestion or hydrolysis.
\13\ Because MDLs reported in EPA Methods 200.7 and 200.9 were determined using a 2X preconcentration step
during sample digestion, MDLs determined when samples are analyzed by direct analysis (i.e., no sample
digestion) will be higher. For direct analysis of cadmium and arsenic by Method 200.7, and arsenic by Method
3120 B sample preconcentration using pneumatic nebulization may be required to achieve lower detection limits.
Preconcentration may also be required for direct analysis of antimony, lead, and thallium by Method 200.9;
antimony and lead by Method 3113 B; and lead by Method D3559-90D unless multiple in-furnace depositions are
made.
\14\ If ultrasonic nebulization is used in the determination of arsenic by Methods 200.7, 200.8, or SM 3120 B,
the arsenic must be in the pentavalent state to provide uniform signal response. For methods 200.7 and 3120 B,
both samples and standards must be diluted in the same mixed acid matrix concentration of nitric and
hydrochloric acid with the addition of 100 [micro]L of 30% hydrogen peroxide per 100ml of solution. For direct
analysis of arsenic with method 200.8 using ultrasonic nebulization, samples and standards must contain one mg/
L of sodium hypochlorite.
\15\ Starting January 23, 2006, analytical methods using the ICP-AES technology, may not be used because the
detection limits for these methods are 0.008 mg/L or higher. This restriction means that the two ICP-AES
methods (EPA Method 200.7 and SM 3120 B) approved for use for the MCL of 0.05 mg/L may not be used for
compliance determinations for the revised MCL of 0.010 mg/L. However, prior to January 23, 2006, systems may
have compliance samples analyzed with these less sensitive methods.
\16\ The description for Method Number 1001 for lead is available from Palintest, LTD, 21 Kenton Lands Road,
P.O. Box 18395, Erlanger, KY 41018. Or from the Hach Company, P.O. Box 389, Loveland, CO 80539.
\17\ The description for the Kelada 01 Method, ``Kelada Automated Test Methods for Total Cyanide, Acid
Dissociable Cyanide, And Thiocyanate'', Revision 1.2, August 2001, EPA 821-B-01-009 for cyanide is
available from the National Technical Information Service (NTIS), PB 2001-108275, 5285 Port Royal Road,
Springfield, VA 22161. The toll free telephone number is 800-553-6847.
\18\ The description for the QuikChem Method 10-204-00-1-X, ``Digestion and distillation of total cyanide in
drinking and wastewaters using MICRO DIST and determination of cyanide by flow injection analysis'', Revision
2.1, November 30, 2000 for cyanide is available from Lachat Instruments, 6645 W. Mill Rd., Milwaukee, WI
53218, USA. Phone: 414-358-4200.
(2) Sample collection for antimony, arsenic, asbestos, barium,
beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel,
nitrate, nitrite, selenium, and thallium under this section shall be
conducted using the sample preservation, container, and maximum holding
time procedures specified in the table below:
------------------------------------------------------------------------
Container
Contaminant Preservative \1\ \2\ Time \3\
------------------------------------------------------------------------
Antimony..................... HNO\3\.......... P or G.... 6 months
Arsenic...................... Conc HNO3 to pH P or G.... 6 months
<2.
Asbestos..................... 4 [deg]C........ P or G.... 48 hours
\4\
Barium....................... HNO\3\.......... P or G.... 6 months
Beryllium.................... HNO\3\.......... P or G.... 6 months
Cadmium...................... HNO\3\.......... P or G.... 6 months
Chromium..................... HNO\3\.......... P or G.... 6 months
Cyanide...................... 4 [deg]C, NaOH.. P or G.... 14 days
Fluoride..................... None............ P or G.... 1 month
Mercury...................... HNO\3\.......... P or G.... 28 days
Nickel....................... HNO\3\.......... P or G.... 6 months
Nitrate...................... 4 [deg]C........ P or G.... 48 hours
\5\
Nitrate-Nitrite \6\.......... H\2\SO\4\....... P or G.... 28 days
Nitrite...................... 4[deg]C......... P or G.... 48 hours
Selenium..................... HNO\3\.......... P or G.... 6 months
Thallium..................... HNO\3\.......... P or G.... 6 months
------------------------------------------------------------------------
\1\ For cyanide determinations samples must be adjusted with sodium
hydroxide to pH 12 at the time off collection. When chilling is
indicated the sample must be shipped and stored at 4 [deg]C or less.
Acidification of nitrate or metals samples may be with a concentrated
acid or a dilute (50% by volume) solution of the applicable
concentrated acid. Acidification of samples for metals analysis is
encouraged and allowed at the laboratory rather than at the time of
sampling provided the shipping time and other instructions in Section
8.3 of EPA Methods 200.7 or 200.8 or 200.9 are followed.
\2\ P=plastic, hard or soft; G=glass, hard or soft.
\3\ In all cases samples should be analyzed as soon after collection as
possible. Follow additional (if any) information on preservation,
containers or holding times that is specified in method.
\4\ Instructions for containers, preservation procedures and holding
times as specified in Method 100.2 must be adhered to for all
compliance analyses including those conducted with Method 100.1.
[[Page 371]]
\5\ If the sample is chlorinated, the holding time for an unacidified
sample kept at 4 [deg]C is extended to 14 days.
\6\ Nitrate-Nitrite refers to a measurement of total nitrate.
(3) Analysis under this section shall only be conducted by
laboratories that have been certified by EPA or the State. Laboratories
may conduct sample analysis under provisional certification until
January 1, 1996. To receive certification to conduct analyses for
antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium,
cyanide, fluoride, mercury, nickel, nitrate, nitrite and selenium and
thallium, the laboratory must:
(i) Analyze Performance Evaluation (PE) samples provided by EPA, the
State or by a third party (with the approval of the State or EPA) at
least once a year.
(ii) For each contaminant that has been included in the PE sample
and for each method for which the laboratory desires certification
achieve quantitative results on the analyses that are within the
following acceptance limits:
------------------------------------------------------------------------
Contaminant Acceptance limit
------------------------------------------------------------------------
Antimony............................ 30 at =0.006 mg/1
Arsenic............................. 30 at =0.003 mg/L
Asbestos............................ 2 standard deviations based on
study statistics.
Barium.............................. 15% at =0.15 mg/1
Beryllium........................... 15% at =0.001 mg/1
Cadmium............................. 20% at =0.002 mg/1
Chromium............................ 15% at =0.01 mg/1
Cyanide............................. 25% at =0.1 mg/1
Fluoride............................ 10% at =1 to 10 mg/1
Mercury............................. 30% at =0.0005 mg/1
Nickel.............................. 15% at =0.01 mg/1
Nitrate............................. 10% at =0.4 mg/1
Nitrite............................. 15% at =0.4 mg/1
Selenium............................ 20% at =0.01 mg/1
Thallium............................ 30% at =0.002 mg/1
------------------------------------------------------------------------
(l) Analyses for the purpose of determining compliance with Sec.
141.11 shall be conducted using the requirements specified in paragraphs
(l) through (q) of this section.
(1) Analyses for all community water systems utilizing surface water
sources shall be completed by June 24, 1978. These analyses shall be
repeated at yearly intervals.
(2) Analyses for all community water systems utilizing only ground
water sources shall be completed by June 24, 1979. These analyses shall
be repeated at three-year intervals.
(3) For non-community water systems, whether supplied by surface or
ground sources, analyses for nitrate shall be completed by December 24,
1980. These analyses shall be repeated at intervals determined by the
State.
(4) The State has the authority to determine compliance or initiate
enforcement action based upon analytical results and other information
compiled by their sanctioned representatives and agencies.
(m) If the result of an analysis made under paragraph (l) of this
section indicates that the level of any contaminant listed in Sec.
141.11 exceeds the maximum contaminant level, the supplier of the water
shall report to the State within 7 days and initiate three additional
analyses at the same sampling point within one month.
(n) When the average of four analyses made pursuant to paragraph (m)
of this section, rounded to the same number of significant figures as
the maximum contaminant level for the substance in question, exceeds the
maximum contaminant level, the supplier of water shall notify the State
pursuant to Sec. 141.31 and give notice to the public pursuant to
subpart Q. Monitoring after public notification shall be at a frequency
designated by the State and shall continue until the maximum contaminant
level has not been exceeded in two successive samples or until a
monitoring schedule as a condition to a variance, exemption or
enforcement action shall become effective.
(o) The provisions of paragraphs (m) and (n) of this section
notwithstanding, compliance with the maximum contaminant level for
nitrate shall be determined on the basis of the mean of two analyses.
When a level exceeding the maximum contaminant level for nitrate is
found, a second analysis shall be initiated within 24 hours, and if the
mean of the two analyses exceeds the maximum contaminant level, the
supplier of water shall report his findings to the State pursuant to
Sec. 141.31 and shall notify the public pursuant to subpart Q.
(p) For the initial analyses required by paragraph (l) (1), (2) or
(3) of this section, data for surface waters acquired within one year
prior to the effective date and data for ground waters
[[Page 372]]
acquired within 3 years prior to the effective date of this part may be
substituted at the discretion of the State.
(q) [Reserved]
[56 FR 3579, Jan. 30, 1991, as amended at 56 FR 30274, July 1, 1991; 57
FR 31838, July 17, 1992; 59 FR 34322, July 1, 1994; 59 FR 62466, Dec. 5,
1994; 60 FR 33932, 34085, June 29, 1995; 64 FR 67461, Dec. 1, 1999; 65
FR 26022, May 4, 2000; 66 FR 7061, Jan. 22, 2001; 67 FR 65246, Oct. 23,
2002; 67 FR 65897, Oct. 29, 2002; 67 FR 68911, Nov. 13, 2002; 68 FR
14506, Mar. 25, 2003]