respect to potentially disproportionate and adverse effects on people
of color, low-income populations and/or indigenous peoples. This action
has no effect on human health or the environment because this action
would approve new and revised versions of CWA testing procedures. The
proposed changes clarify or improve the instructions in the method,
update the technology used in the method, improve the QC instructions,
make editorial corrections, or reflect the most recent approval year of
an already approved method. These proposed changes would provide
increased flexibility for the regulated community in meeting monitoring
requirements while improving data quality. In addition, this proposed
update to the CWA methods would incorporate technological advances in
analytical technology.

List of Subjects in 40 CFR Part 136

    Environmental protection, Incorporation by reference, Reporting and
recordkeeping requirements, Test procedures, Water pollution control.

Michael S. Regan,
Administrator.
    For the reasons set out in the preamble, the EPA proposes to amend
40 CFR part 136 as follows:

PART 136--GUIDELINES ESTABLISHING TEST PROCEDURES FOR THE ANALYSIS
OF POLLUTANTS

0
1. The authority citation for part 136 continues to read as follows:

    Authority: Secs. 301, 304(h), 307 and 501(a), Pub. L. 95-217, 91
Stat. 1566, et seq. (33 U.S.C. 1251, et seq.) (the Federal Water
Pollution Control Act Amendments of 1972 as amended by the Clean
Water Act of 1977).
0
2. Amend Sec.  136.3 as follows:
0
a. Revise tables IA, IB, IC, ID, and IH in paragraph (a);
0
b. Revise the introductory text to paragraph (b) and paragraphs
(b)(8)(ii) through (v), (b)(10)(i), (viii) through (xiv), (xvi) through
(xxvi), (xxviii) through (xxxv), (xxxvii), (xxxix) through (li), (lv)
through (lxiii), and (lxvii), (b)(15)(xi), (xx), (xxx), (xxxii), (lix),
(lxv) through (lxvii), and (lxix);
0
c. Redesignate paragraphs (b)(33) through (39) as paragraphs (b)(35)
through (41);
0
d. Add new paragraphs (b)(33) and (34); and
0
e. In paragraph (e), table II, revise Footnote ``5''.
    The revisions and additions read as follows:

Sec.  136.3  Identification of test procedures.

* * * * *

                                     Table IA--List of Approved Biological Methods for Wastewater and Sewage Sludge
--------------------------------------------------------------------------------------------------------------------------------------------------------
       Parameter and units             Method \1\              EPA            Standard methods       AOAC, ASTM, USGS                  Other
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Bacteria
--------------------------------------------------------------------------------------------------------------------------------------------------------
1. Coliform (fecal), number per   Most Probable        p. 132; \3\ 1680;    9221 E-2014........
 gram dry weight.                  Number (MPN), 5      \11\ \15\ 1681
                                   tube, 3 dilution,    \11\ \20\.
                                   or
                                  Membrane filter      p. 124 \3\.........  9222 D-2015 \29\...
                                   (MF),\2\ \5\
                                   single step.
2. Coliform (fecal), number per   MPN, 5 tube, 3       p. 132 \3\.........  9221 E-2014; 9221 F-
 100 mL.                           dilution, or.                             2014 \33\.
                                  Multiple tube/       ...................  ...................  ........................  Colilert-18[supreg].\13\ \18\
                                   multiple well, or.                                                                       \28\
                                  MF,\2\ \5\ single    p. 124 \3\.........  9222 D-2015 \29\...  B-0050-85 \4\...........
                                   step \5\.
3. Coliform (total), number per   MPN, 5 tube, 3       p. 114 \3\.........  9221 B-2014........
 100 mL.                           dilution, or.
                                  MF,\2\ \5\ single    p. 108 \3\.........  9222 B-2015 \30\...  B-0025-85 \4\...........
                                   step or.
                                  MF,\2\ \5\ two step  p. 111 \3\.........  9222 B-2015 \30\...
                                   with enrichment.
4. E. coli, number per 100 mL...  MPN \6\ \8\ \16\     ...................  9221 B2014/9221 F-
                                   multiple tube, or.                        2014 \12\ \14\
                                                                             \33\.
                                  multiple tube/       ...................  9223 B-2016 \13\...  991.15 \10\.............  Colilert[supreg].\13\ \18\
                                   multiple well, or.                                                                      Colilert-18[supreg].\13\ \17\
                                                                                \18\
                                  MF,\2\ \5\ \6\ \7\   ...................  9222 B-2015/9222 I-
                                   \8\ two step, or.                         2015 \31\.
                                  Single step........  1603.1 \21\........  ...................  ........................  m-ColiBlue24[supreg].\19\
5. Fecal streptococci, number     MPN, 5 tube, 3       p. 139 \3\.........  9230 B-2013........
 per 100 mL.                       dilution, or.
                                  MF,\2\ or..........  p. 136 \3\.........  9230 C-2013 \32\...  B-0055-85 \4\...........
                                  Plate count........  p. 143 \3\.........
6. Enterococci, number per 100    MPN, 5 tube, 3       p. 139 \3\.........  9230 B-2013........
 mL.                               dilution, or.

                                  MPN,\6\ \8\          ...................  9230 D-2013........  D6503-99 \9\............  Enterolert[supreg].\13\ \23\
                                   multiple tube/
                                   multiple well, or.
                                  MF \2\ \5\ \6\ \7\   1600.1 \24\........  9230 C-2013 \32\...
                                   \8\ single step or.
                                  Plate count........  p. 143 \3\.........
7. Salmonella, number per gram    MPN multiple tube..  1682 \22\..........
 dry weight \11\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Aquatic Toxicity
--------------------------------------------------------------------------------------------------------------------------------------------------------
8. Toxicity, acute, fresh water   Water flea,          2002.0 \25\........
 organisms, LC50, percent          Cladoceran,
 effluent.                         Ceriodaphnia dubia
                                   acute.
                                  Water fleas,         2021.0 \25\........
                                   Cladocerans,
                                   Daphnia pulex and
                                   Daphnia magna
                                   acute.
                                  Fish, Fathead        2000.0 \25\........
                                   minnow, Pimephales
                                   promelas, and
                                   Bannerfin shiner,
                                   Cyprinella leedsi,
                                   acute.
                                  Fish, Rainbow        2019.0 \25\........
                                   trout,
                                   Oncorhynchus
                                   mykiss, and brook
                                   trout, Salvelinus
                                   fontinalis, acute.
9. Toxicity, acute, estuarine     Mysid, Mysidopsis    2007.0 \25\.
 and marine organisms of the       bahia, acute.       ...................
 Atlantic Ocean and Gulf of       Fish, Sheepshead     2004.0 \25\........
 Mexico, LC50, percent effluent.   minnow, Cyprinodon
                                   variegatus, acute.
                                  Fish, Silverside,    2006.0 \25\........
                                   Menidia beryllina,
                                   Menidia menidia,
                                   and Menidia
                                   peninsulae, acute.
10. Toxicity, chronic, fresh      Fish, Fathead        1000.0 \26\........
 water organisms, NOEC or IC25,    minnow, Pimephales
 percent effluent.                 promelas, larval
                                   survival and
                                   growth.
                                  Fish, Fathead        1001.0 \26\........
                                   minnow, Pimephales
                                   promelas, embryo-
                                   larval survival
                                   and teratogenicity.
                                  Water flea,          1002.0 \26\........
                                   Cladoceran,
                                   Ceriodaphnia
                                   dubia, survival
                                   and reproduction.
                                  Green alga,          1003.0 \26\........
                                   Selenastrum
                                   capricornutum,
                                   growth.
11. Toxicity, chronic, estuarine  Fish, Sheepshead     1004.0 \27\........
 and marine organisms of the       minnow, Cyprinodon
 Atlantic Ocean and Gulf of        variegatus, larval
 Mexico, NOEC or IC25, percent     survival and
 effluent.                         growth.

                                  Fish, Sheepshead     1005.0 \27\........
                                   minnow, Cyprinodon
                                   variegatus, embryo-
                                   larval survival
                                   and teratogenicity.
                                  Fish, Inland         1006.0 \27\........
                                   silverside,
                                   Menidia beryllina,
                                   larval survival
                                   and growth.
                                  Mysid, Mysidopsis    1007.0 \27\........
                                   bahia, survival,
                                   growth, and
                                   fecundity.
                                  Sea urchin, Arbacia  1008.0 \27\........
                                   punctulata,
                                   fertilization.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table IA notes:
\1\ The method must be specified when results are reported.
\2\ A 0.45-[mu]m membrane filter (MF) or other pore size certified by the manufacturer to fully retain organisms to be cultivated and to be free of
  extractables which could interfere with their growth.
\3\ Microbiological Methods for Monitoring the Environment, Water and Wastes, EPA/600/8-78/017. 1978. U.S. EPA.
\4\ U.S. Geological Survey Techniques of Water-Resource Investigations, Book 5, Laboratory Analysis, Chapter A4, Methods for Collection and Analysis of
  Aquatic Biological and Microbiological Samples. 1989. USGS.
\5\ Because the MF technique usually yields low and variable recovery from chlorinated wastewaters, the Most Probable Number method will be required to
  resolve any controversies.
\6\ Tests must be conducted to provide organism enumeration (density). Select the appropriate configuration of tubes/filtrations and dilutions/volumes
  to account for the quality, character, consistency, and anticipated organism density of the water sample.
\7\ When the MF method has been used previously to test waters with high turbidity, large numbers of noncoliform bacteria, or samples that may contain
  organisms stressed by chlorine, a parallel test should be conducted with a multiple-tube technique to demonstrate applicability and comparability of
  results.
\8\ To assess the comparability of results obtained with individual methods, it is suggested that side-by-side tests be conducted across seasons of the
  year with the water samples routinely tested in accordance with the most current Standard Methods for the Examination of Water and Wastewater or EPA
  alternate test procedure (ATP) guidelines.
\9\ Annual Book of ASTM Standards-Water and Environmental Technology, Section 11.02. 2000, 1999, 1996. ASTM International.
\10\ Official Methods of Analysis of AOAC International. 16th Edition, 4th Revision, 1998. AOAC International.
\11\ Recommended for enumeration of target organism in sewage sludge.
\12\ The multiple-tube fermentation test is used in 9221B.2-2014. Lactose broth may be used in lieu of lauryl tryptose broth (LTB), if at least 25
  parallel tests are conducted between this broth and LTB using the water samples normally tested, and this comparison demonstrates that the false-
  positive rate and false-negative rate for total coliform using lactose broth is less than 10 percent. No requirement exists to run the completed phase
  on 10 percent of all total coliform-positive tubes on a seasonal basis.
\13\ These tests are collectively known as defined enzyme substrate tests.
\14\ After prior enrichment in a presumptive medium for total coliform using 9221B.2-2014, all presumptive tubes or bottles showing any amount of gas,
  growth or acidity within 48 h  3 h of incubation shall be submitted to 9221F-2014. Commercially available EC-MUG media or EC media
  supplemented in the laboratory with 50 [mu]g/mL of MUG may be used.
\15\ Method 1680: Fecal Coliforms in Sewage Sludge (Biosolids) by Multiple-Tube Fermentation Using Lauryl-Tryptose Broth (LTB) and EC Medium, EPA-821-R-
  14-009. September 2014. U.S. EPA.
\16\ Samples shall be enumerated by the multiple-tube or multiple-well procedure. Using multiple-tube procedures, employ an appropriate tube and
  dilution configuration of the sample as needed and report the Most Probable Number (MPN). Samples tested with Colilert[supreg] may be enumerated with
  the multiple-well procedures, Quanti-Tray[supreg] or Quanti-Tray[supreg]/2000 and the MPN calculated from the table provided by the manufacturer.
\17\ Colilert-18[supreg] is an optimized formulation of the Colilert[supreg] for the determination of total coliforms and E. coli that provides results
  within 18 h of incubation at 35[deg]C rather than the 24 h required for the Colilert[supreg] test and is recommended for marine water samples.
\18\ Descriptions of the Colilert[supreg], Colilert-18[supreg], Quanti-Tray[supreg], and Quanti-Tray[supreg]/2000 may be obtained from IDEXX
  Laboratories, Inc.
\19\ A description of the mColiBlue24[supreg] test is available from Hach Company.
\20\ Method 1681: Fecal Coliforms in Sewage Sludge (Biosolids) by Multiple-Tube Fermentation Using A-1 Medium, EPA-821-R-06-013. July 2006. U.S. EPA.
\21\ Method 1603.1: Escherichia coli (E. coli) in Water by Membrane Filtration Using Modified Membrane-Thermotolerant Escherichia coli Agar (modified
  mTEC), [in draft as of 2023]. U.S. EPA.
\22\ Method 1682: Salmonella in Sewage Sludge (Biosolids) by Modified Semisolid Rappaport-Vassiliadis (MSRV) Medium, EPA-821-R-14-012. September 2014.
  U.S. EPA.
\23\ A description of the Enterolert[supreg] test may be obtained from IDEXX Laboratories Inc.
\24\ Method 1600.1: Enterococci in Water by Membrane Filtration Using Membrane-Enterococcus Indoxyl-[beta]-D-Glucoside Agar (mEI), [in draft as of
  2023]. U.S. EPA.
\25\ Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, EPA-821-R-02-012. Fifth Edition,
  October 2002. U.S. EPA; and U.S. EPA Whole Effluent Toxicity Methods Errata Sheet, EPA 821-R-02-012-ES. December 2016.
\26\ Short-term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms, EPA-821-R-02-013. Fourth Edition,
  October 2002. U.S. EPA; and U.S. EPA Whole Effluent Toxicity Methods Errata Sheet, EPA 821-R-02-012-ES. December 2016.
\27\ Short-term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Marine and Estuarine Organisms, EPA-821-R-02-014. Third
  Edition, October 2002. U.S. EPA; and U.S. EPA Whole Effluent Toxicity Methods Errata Sheet, EPA 821-R-02-012-ES. December 2016.
\28\ To use Colilert-18[supreg] to assay for fecal coliforms, the incubation temperature is 44.5  0.2 [deg]C, and a water bath incubator is
  used.
\29\ On a monthly basis, at least ten blue colonies from positive samples must be verified using Lauryl Tryptose Broth and EC broth, followed by count
  adjustment based on these results; and representative non-blue colonies should be verified using Lauryl Tryptose Broth. Where possible, verifications
  should be done from randomized sample sources.
\30\ On a monthly basis, at least ten sheen colonies from positive samples must be verified using lauryl tryptose broth and brilliant green lactose bile
  broth, followed by count adjustment based on these results; and representative non-sheen colonies should be verified using lauryl tryptose broth.
  Where possible, verifications should be done from randomized sample sources.

\31\ Subject coliform positive samples determined by 9222 B-2015 or other membrane filter procedure to 9222 I-2015 using NA-MUG media.
\32\ Verification of colonies by incubation of BHI agar at 10  0.5 [deg]C for 48  3 h is optional. As per the Errata to the 23rd
  Edition of Standard Methods for the Examination of Water and Wastewater ``Growth on a BHI agar plate incubated at 10  0.5 [deg]C for 48
   3 h is further verification that the colony belongs to the genus Enterococcus.''
\33\ 9221F. 2-2014 allows for simultaneous detection of E. coli and thermotolerant fecal coliforms by adding inverted vials to EC-MUG; the inverted
  vials collect gas produced by thermotolerant fecal coliforms.

                                                  Table IB--List of Approved Inorganic Test Procedures
--------------------------------------------------------------------------------------------------------------------------------------------------------
             Parameter                  Methodology \58\            EPA \52\         Standard methods \84\           ASTM             USGS/AOAC/other
--------------------------------------------------------------------------------------------------------------------------------------------------------
1. Acidity, as CaCO3, mg/L.........  Electrometric endpoint  ......................  2310 B-2020..........  D1067-16.............  I-1020-85.\2\
                                      or phenolphthalein
                                      endpoint.
2. Alkalinity, as CaCO3, mg/L......  Electrometric or        ......................  2320 B-2021..........  D1067-16.............  973.43,\3\ I-1030-
                                      Colorimetric                                                                                85.\2\
                                      titration to pH 4.5,
                                      Manual.
                                     Automatic.............  310.2 (Rev. 1974) \1\.  .....................  .....................  I-2030-85.\2\
3. Aluminum--Total, \4\ mg/L.......  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration    ......................  3111 D-2019 or 3111 E- .....................  I-3051-85.\2\
                                      \36\.                                           2019.
                                     AA furnace............  ......................  3113 B-2020..........
                                     STGFAA................  200.9, Rev. 2.2 (1994)
                                     ICP/AES \36\..........  200.5, Rev 4.2          3120 B-2020..........  D1976-20.............  I-4471-97.\50\
                                                              (2003),\68\ 200.7,
                                                              Rev. 4.4 (1994).
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14,\3\ I-4472-
                                                                                97.\81\
                                     Direct Current Plasma   ......................  .....................  D4190-15.............  See footnote.\34\
                                      (DCP) \36\.
                                     Colorimetric            ......................  3500-Al B-2020.......
                                      (Eriochrome cyanine
                                      R).
4. Ammonia (as N), mg/L............  Manual distillation     350.1, Rev. 2.0 (1993)  4500-NH3 B-2021......  .....................  973.49.\3\
                                      \6\ or gas diffusion
                                      (pH > 11), followed
                                      by any of the
                                      following:
                                     Nesslerization........  ......................  .....................  D1426-15 (A).........  973.49,\3\ I-3520-
                                                                                85.\2\
                                     Titration.............  ......................  4500-NH3 C-2021......
                                     Electrode.............  ......................  4500-NH3 D-2021 or E-  D1426-15 (B).........
                                                                                2021.
                                     Manual phenate,         ......................  4500-NH3 F-2021......  .....................  See footnote.\60\
                                      salicylate, or other
                                      substituted phenols
                                      in Berthelot reaction-
                                      based methods.
                                     Automated phenate,      350.1,\30\ Rev. 2.0     4500-NH3 G-2021 4500-  .....................  I-4523-85,\2\ I-2522-
                                      salicylate, or other    (1993).                 NH3 H-2021.                                   90.\80\
                                      substituted phenols
                                      in Berthelot reaction-
                                      based methods.
                                     Automated electrode...  ......................  .....................  .....................  See footnote.\7\
                                     Ion Chromatography....  ......................  .....................  D6919-17.............
                                     Automated gas           ......................  .....................  .....................  Timberline Ammonia-
                                      diffusion, followed                                                                           001.\74\
                                      by conductivity cell
                                      analysis.
                                     Automated gas           ......................  .....................  .....................  FIAlab100.\82\
                                      diffusion followed by
                                      fluorescence detector
                                      analysis.
5. Antimony--Total, \4\ mg/L.......  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration    ......................  3111 B-2019..........
                                      \36\.
                                     AA furnace............  ......................  3113 B-2020..........
                                     STGFAA................  200.9, Rev. 2.2 (1994)
                                     ICP/AES \36\..........  200.5, Rev 4.2 (2003);  3120 B-2020..........  D1976-20.............
                                                              \68\ 200.7, Rev. 4.4
                                                              (1994).

                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14,\3\ I-4472-
                                                                                97.\81\
6. Arsenic--Total,\4\ mg/L.........  Digestion,\4\ followed  206.5 (Issued 1978)
                                      by any of the           \1\.
                                      following:
                                     AA gaseous hydride....  ......................  3114 B-2020 or 3114 C- D2972-15 (B).........  I-3062-85.\2\
                                                                                2020.
                                     AA furnace............  ......................  3113 B-2020..........  D2972-15 (C).........  I-4063-98.\49\
                                     STGFAA................  200.9, Rev. 2.2 (1994)
                                     ICP/AES \36\..........  200.5, Rev 4.2 (2003);  3120 B-2020..........  D1976-20.............
                                                              \68\ 200.7, Rev. 4.4
                                                              (1994).
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14,\3\ I-4020-
                                                                                05.\70\
                                     Colorimetric (SDDC)...  ......................  3500-As B-2020.......  D2972-15 (A).........  I-3060-85.\2\
7. Barium--Total,\4\ mg/L..........  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration    ......................  3111 D-2019..........  .....................  I-3084-85.\2\
                                      \36\.
                                     AA furnace............  ......................  3113 B-2020..........  D4382-18.............
                                     ICP/AES \36\..........  200.5, Rev 4.2 (2003);  3120 B-2020..........  .....................  I-4471-97.\50\
                                                              \68\ 200.7, Rev. 4.4
                                                              (1994).
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14,\3\ I-4472-
                                                                                97.\81\
                                     DCP \36\..............  ......................  .....................  .....................  See footnote.\34\
8. Beryllium--Total,\4\ mg/L.......  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration..  ......................  3111 D-2019 or 3111 E- D3645-15 (A).........  I-3095-85.\2\
                                                                                2019.
                                     AA furnace............  ......................  3113 B-2020..........  D3645-15 (B).........
                                     STGFAA................  200.9, Rev. 2.2 (1994)
                                     ICP/AES...............  200.5, Rev 4.2 (2003);  3120 B-2020..........  D1976-20.............  I-4471-97.\50\
                                                              \68\ 200.7, Rev. 4.4
                                                              (1994).
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14,\3\ I-4472-
                                                                                97.\81\
                                     DCP...................  ......................  .....................  D4190-15.............  See footnote.\34\
                                     Colorimetric            ......................  See footnote.\61\....
                                      (aluminon).
9. Biochemical oxygen demand         Dissolved Oxygen        ......................  5210 B-2016 \85\.....  .....................  973.44,\3\ p. 17,\9\
 (BOD5), mg/L.                        Depletion.                                                                                I-1578-78,\8\ See
                                                                                footnote.\10\ \63\
10. Boron--Total,\37\ mg/L.........  Colorimetric            ......................  4500-B B-2011........  .....................  I-3112-85.\2\
                                      (curcumin).
                                     ICP/AES...............  200.5, Rev 4.2 (2003);  3120 B-2020..........  D1976-20.............  I-4471-97.\50\
                                                              \68\ 200.7, Rev. 4.4
                                                              (1994).
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14.\3\
                                     DCP...................  ......................  .....................  D4190-15.............  See footnote.\34\
11. Bromide, mg/L..................  Electrode.............  ......................  .....................  D1246-16.............  I-1125-85.\2\
                                     Ion Chromatography....  300.0, Rev 2.1 (1993)   4110 B-2020, C-2020    D4327-17.............  993.30,\3\ I-2057-
                                                              and 300.1, Rev 1.0      or D-2020.                                    85.\79\
                                                              (1997).
                                     CIE/UV................  ......................  4140 B-2020..........  D6508-15.............  D6508, Rev. 2.\54\
12. Cadmium--Total,\4\ mg/L........  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration    ......................  3111 B-2019 or 3111 C- D3557-17 (A or B)....  974.27,\3\ p. 37,\9\
                                      \36\.                                           2019.                                         I-3135-85 \2\ or I-
                                                                                3136-85.\2\
                                     AA furnace............  ......................  3113 B-2020..........  D3557-17 (D).........  I-4138-89.\51\
                                     STGFAA................  200.9, Rev. 2.2 (1994)
                                     ICP/AES \36\..........  200.5, Rev 4.2 (2003);  3120 B-2020..........  D1976-20.............  I-1472-85 \2\ or I-
                                                              \68\ 200.7, Rev. 4.4                                                  4471-97.\50\
                                                              (1994).

                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14,\3\ I-4472-
                                                                                97.\81\
                                     DCP \36\..............  ......................  .....................  D4190-15.............  See footnote.\34\
                                     Voltammetry \11\......  ......................  .....................  D3557-17 (C).........
                                     Colorimetric            ......................  3500-Cd-D-1990.......
                                      (Dithizone).
13. Calcium--Total,\4\ mg/L........  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration..  ......................  3111 B-2019 or 3111 D- D511-14 (B)..........  I-3152-85.\2\
                                                                                2019.
                                     ICP/AES...............  200.5, Rev 4.2 (2003);  3120 B-2020..........  .....................  I-4471-97.\50\
                                                              \68\ 200.7, Rev. 4.4
                                                              (1994).
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14.\3\
                                     DCP...................  ......................  .....................  .....................  See footnote.\34\
                                     Titrimetric (EDTA)....  ......................  3500-Ca B-2020.......  D511-14 (A)..........
                                     Ion Chromatography....  ......................  .....................  D6919-17.............
14. Carbonaceous biochemical oxygen  Dissolved Oxygen        ......................  5210 B-2016 \85\.....  .....................  See footnote.\35\
 demand (CBOD5), mg/L \12\.           Depletion with                                                                                \63\
                                      nitrification
                                      inhibitor.
15. Chemical oxygen demand (COD),    Titrimetric...........  410.3 (Rev. 1978) \1\.  5220 B-2011 or C-2011  D1252-06(12) (A).....  973.46,\3\ p. 17,\9\
 mg/L.                                                                                I-3560-85.\2\
                                     Spectrophotometric,     410.4, Rev. 2.0 (1993)  5220 D-2011..........  D1252-06(12) (B).....  See footnotes,\13\
                                      manual or automatic.                                                                          \14\ \83\ I-3561-
                                                                                85.\2\
16. Chloride, mg/L.................  Titrimetric: (silver    ......................  4500-Cl- B-2021......  D512-12 (B)..........  I-1183-85.\2\
                                      nitrate).
                                     (Mercuric nitrate)....  ......................  4500-Cl- C-2021......  D512-12 (A)..........  973.51,\3\ I-1184-
                                                                                85.\2\
                                     Colorimetric: manual..  ......................  .....................  .....................  I-1187-85.\2\
                                     Automated               ......................  4500-Cl- E-2021......  .....................  I-2187-85.\2\
                                      (ferricyanide).
                                     Potentiometric          ......................  4500-Cl- D-2021......
                                      Titration.
                                     Ion Selective           ......................  .....................  D512-12 (C)..........
                                      Electrode.
                                     Ion Chromatography....  300.0, Rev 2.1 (1993)   4110 B-2020 or 4110 C- D4327-17.............  993.30,\3\ I-2057-
                                                              and 300.1, Rev 1.0      2020.                                         90.\51\
                                                              (1997).
                                     CIE/UV................  ......................  4140 B-2020..........  D6508-15.............  D6508, Rev. 2.\54\
17. Chlorine--Total residual, mg/L.  Amperometric direct...  ......................  4500-Cl D-2011.......  D1253-14.............
                                     Amperometric direct     ......................  4500-Cl E-2011.......
                                      (low level).
                                     Iodometric direct.....  ......................  4500-Cl B-2011.......
                                     Back titration ether    ......................  4500-Cl C-2011.......
                                      end-point \15\.
                                     DPD-FAS...............  ......................  4500 Cl F-2011.......
                                     Spectrophotometric,     ......................  4500-Cl G-2011.......
                                      DPD.
                                     Electrode.............  ......................  .....................  .....................  See footnote.\16\
17A. Chlorine-Free Available, mg/L.  Amperometric direct...  ......................  4500-Cl D-2011.......  D1253-14.............
                                     Amperometric direct     ......................  4500-Cl E-2011.......
                                      (low level).
                                     DPD-FAS...............  ......................  4500-Cl F-2011.......
                                     Spectrophotometric,     ......................  4500-Cl G-2011.......
                                      DPD.
18. Chromium VI dissolved, mg/L....  0.45-micron filtration
                                      followed by any of
                                      the following:
                                     AA chelation-           ......................  3111 C-2019..........  .....................  I-1232-85.\2\
                                      extraction.
                                     Ion Chromatography....  218.6, Rev. 3.3 (1994)  3500-Cr C-2020.......  D5257-17.............  993.23.\3\
                                     Colorimetric (diphenyl- ......................  3500-Cr B-2020.......  D1687-17 (A).........  I-1230-85.\2\
                                      carbazide).

19. Chromium--Total,\4\ mg/L.......  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration    ......................  3111 B-2019..........  D1687-17 (B).........  974.27,\3\ I-3236-
                                      \36\.                                                                                85.\2\
                                     AA chelation-           ......................  3111 C-2019..........
                                      extraction.
                                     AA furnace............  ......................  3113 B-2020..........  D1687-17 (C).........  I-3233-93.\46\
                                     STGFAA................  200.9, Rev. 2.2 (1994)
                                     ICP/AES \36\..........  200.5, Rev 4.2          3120 B-2020..........  D1976-20.............
                                                              (2003),\68\ 200.7,
                                                              Rev. 4.4 (1994).
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14,\3\ I-4020-05
                                                                                \70\ I-4472-97.\81\
                                     DCP \36\..............  ......................  .....................  D4190-15.............  See footnote.\34\
                                     Colorimetric (diphenyl- ......................  3500-Cr B-2020.......
                                      carbazide).
20. Cobalt--Total,\4\ mg/L.........  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration..  ......................  3111 B-2019 or 3111 C- D3558-15 (A or B)....  p. 37,\9\ I-3239-
                                                                                2019.                                         85.\2\
                                     AA furnace............  ......................  3113 B-2020..........  D3558-15 (C).........  I-4243-89.\51\
                                     STGFAA................  200.9, Rev. 2.2 (1994)
                                     ICP/AES...............  200.7, Rev. 4.4 (1994)  3120 B-2020..........  D1976-20.............  I-4471-97.\50\
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14,\3\ I-4020-05
                                                                                \70\ I-4472-97.\81\
                                     DCP...................  ......................  .....................  D4190-15.............  See footnote.\34\
21. Color, platinum cobalt units or  Colorimetric (ADMI)...  ......................  2120 F-2021 \78\.....
 dominant wavelength, hue,
 luminance purity.
                                     Platinum cobalt visual  ......................  2120 B-2021..........  .....................  I-1250-85.\2\
                                      comparison.
                                     Spectrophotometric....  ......................  .....................  .....................  See footnote.\18\
22. Copper--Total,\4\ mg/L.........  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration    ......................  3111 B-2019 or 3111 C- D1688-17 (A or B)....  974.27,\3\ p. 37,\9\
                                      \36\.                                           2019.                                         I-3270-85 \2\ or I-
                                                                                3271-85.\2\
                                     AA furnace............  ......................  3113 B-2020..........  D1688-17 (C).........  I-4274-89.\51\
                                     STGFAA................  200.9, Rev. 2.2 (1994)
                                     ICP/AES \36\..........  200.5, Rev 4.2 (2003);  3120 B-2020..........  D1976-20.............  I-4471-97.\50\
                                                              \68\ 200.7, Rev. 4.4
                                                              (1994).
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14,\3\ I-4020-
                                                                                05,\70\ I-4472-
                                                                                97.\81\
                                     DCP \36\..............  ......................  .....................  D4190-15.............  See footnote.\34\
                                     Colorimetric            ......................  3500-Cu B-2020.......
                                      (Neocuproine).
                                     Colorimetric            ......................  3500-Cu C-2020.......  .....................  See footnote.\19\
                                      (Bathocuproine).
23. Cyanide--Total, mg/L...........  Automated UV digestion/ ......................  .....................  .....................  Kelada-01.\55\
                                      distillation and
                                      Colorimetry.
                                     Segmented Flow          ......................  4500-CN- P-2021......  D7511-12(17).........
                                      Injection, In-Line
                                      Ultraviolet
                                      Digestion, followed
                                      by gas diffusion
                                      amperometry.
                                     Manual distillation     335.4, Rev. 1.0 (1993)  4500-CN- B-2021 and C- D2036-09(15)(A),       10-204-00-1-X.\56\
                                      with MgCl2, followed    \57\.                   2021.                  D7284-20.
                                      by any of the
                                      following:
                                     Flow Injection, gas     ......................  .....................  D2036-09(15)(A) D7284-
                                      diffusion amperometry.                                                 20.

                                     Titrimetric...........  ......................  4500-CN- D-2021......  D2036-09(15)(A)......  p. 22.\9\
                                     Spectrophotometric,     ......................  4500-CN- E-2021......  D2036-09(15)(A)......  I-3300-85.\2\
                                      manual.
                                     Semi-Automated \20\...  335.4, Rev. 1.0 (1993)  4500-CN- N-2021......  .....................  10-204-00-1-X,\56\ I-
                                                              \57\.                                                                 4302-85.\2\
                                     Ion Chromatography....  ......................  .....................  D2036-09(15)(A)......
                                     Ion Selective           ......................  4500-CN- F-2021......  D2036-09(15)(A)......
                                      Electrode.
24. Cyanide-Available, mg/L........  Cyanide Amenable to     ......................  4500-CN- G-2021......  D2036-09(15)(B)......
                                      Chlorination (CATC);
                                      Manual distillation
                                      with MgCl2, followed
                                      by Titrimetric or
                                      Spectrophotometric.
                                     Flow injection and      ......................  4500-CN- Q-2021......  D6888-16.............  OIA-1677-09.\44\
                                      ligand exchange,
                                      followed by gas
                                      diffusion amperometry
                                      \59\.
                                     Automated Distillation  ......................  .....................  .....................  Kelada-01.\55\
                                      and Colorimetry (no
                                      UV digestion).
24. A Cyanide-Free, mg/L...........  Flow Injection,         ......................  4500-CN- R-2021......  D7237-18 (A).........  OIA-1677-09.\44\
                                      followed by gas
                                      diffusion amperometry.
                                     Manual micro-diffusion  ......................  .....................  D4282-15.............
                                      and colorimetry.
25. Fluoride--Total, mg/L..........  Manual                  ......................  4500-F- B-2021.......  D1179-16 (A).........
                                      distillation,\6\
                                      followed by any of
                                      the following:
                                     Electrode, manual.....  ......................  4500-F- C-2021.......  D1179-16 (B).........
                                     Electrode, automated..  ......................  4500-F- G-2021.......  .....................  I-4327-85.\2\
                                     Colorimetric, (SPADNS)  ......................  4500-F- D-2021.......
                                     Automated complexone..  ......................  4500-F- E-2021.......
                                     Ion Chromatography....  300.0, Rev 2.1 (1993)   4110 B-2020 or C-2020  D4327-17.............  993.30.\3\
                                                              and 300.1, Rev 1.0
                                                              (1997).
                                     CIE/UV................  ......................  4140 B-2020..........  D6508-15.............  D6508, Rev. 2.\54\
26. Gold--Total,\4\ mg/L...........  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration..  ......................  3111 B-2019..........
                                     AA furnace............  231.2 (Issued 1978)     3113 B-2020..........
                                                              \1\.
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14.\3\
                                     DCP...................  ......................  .....................  .....................  See footnote.\34\
27. Hardness--Total, as CaCO3, mg/L  Automated colorimetric  130.1 (Issued 1971)
                                                              \1\.
                                     Titrimetric (EDTA)....  ......................  2340 C-2021..........  D1126-17.............  973.52B,\3\ I-1338-
                                                                                85.\2\
                                     Ca plus Mg as their     ......................  2340 B-2021..........
                                      carbonates, by any
                                      approved method for
                                      Ca and Mg (See
                                      Parameters 13 and
                                      33), provided that
                                      the sum of the lowest
                                      point of quantitation
                                      for Ca and Mg is
                                      below the NPDES
                                      permit requirement
                                      for Hardness.
28. Hydrogen ion (pH), pH units....  Electrometric           ......................  4500-H\+\ B-2021.....  D1293-18 (A or B)....  973.41,\3\ I-1586-
                                      measurement.                                                                                85.\2\
                                     Automated electrode...  150.2 (Dec. 1982) \1\.  .....................  .....................  See footnote,\21\ I-
                                                                                2587-85.\2\

29. Iridium--Total,\4\ mg/L........  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration..  ......................  3111 B-2019..........
                                     AA furnace............  235.2 (Issued 1978)
                                                              \1\.
                                     ICP/MS................  ......................  3125 B-2020..........
30. Iron--Total,\4\ mg/L...........  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration    ......................  3111 B-2019 or 3111 C- D1068-15 (A).........  974.27,\3\ I-3381-
                                      \36\.                                           2019.                                         85.\2\
                                     AA furnace............  ......................  3113 B-2020..........  D1068-15 (B).........
                                     STGFAA................  200.9, Rev. 2.2 (1994)
                                     ICP/AES \36\..........  200.5, Rev. 4.2         3120 B-2020..........  D1976-20.............  I-4471-97.\50\
                                                              (2003); \68\ 200.7,
                                                              Rev. 4.4 (1994).
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14.\3\
                                     DCP \36\..............  ......................  .....................  D4190-15.............  See footnote.\34\
                                     Colorimetric            ......................  3500-Fe B-2011.......  D1068-15 (C).........  See footnote.\22\
                                      (Phenanthroline).
31. Kjeldahl Nitrogen \5\--Total,    Manual digestion \20\   ......................  4500-Norg B-2021 or C- D3590-17 (A).........  I-4515-91.\45\
 (as N), mg/L.                        and distillation or                             2021 and 4500-NH3 B-
                                      gas diffusion,                                  2021.
                                      followed by any of
                                      the following:
                                     Titration.............  ......................  4500-NH3 C-2021......  .....................  973.48.\3\
                                     Nesslerization........  ......................  .....................  D1426-15 (A).........
                                     Electrode.............  ......................  4500-NH3 D-2021 or E-  D1426-15 (B).........
                                                                                2021.
                                     Semi-automated phenate  350.1, Rev. 2.0 (1993)  4500-NH3 G-2021 or
                                                                                4500-NH3 H-2021.
                                     Manual phenate,         ......................  4500-NH3 F-2021......  .....................  See footnote.\60\
                                      salicylate, or other
                                      substituted phenols
                                      in Berthelot reaction
                                      based methods.
                                     Automated gas           ......................  .....................  .....................  Timberline Ammonia-
                                      diffusion, followed                                                                           001.\74\
                                      by conductivity cell
                                      analysis.
                                     Automated gas           ......................  .....................  .....................  FIAlab 100.\82\
                                      diffusion followed by
                                      fluorescence detector
                                      analysis.
                                                              Automated Methods for TKN that do not require manual distillation
                                     Automated phenate,      351.1 (Rev. 1978) \1\.  .....................  .....................  I-4551-78.\8\
                                      salicylate, or other
                                      substituted phenols
                                      in Berthelot reaction-
                                      based methods
                                      colorimetric (auto
                                      digestion and
                                      distillation).
                                     Semi-automated block    351.2, Rev. 2.0 (1993)  4500-Norg D-2021.....  D3590-17 (B).........  I-4515-91.\45\
                                      digestor colorimetric
                                      (distillation not
                                      required).
                                     Block digester,         ......................  .....................  .....................  See footnote.\39\
                                      followed by Auto
                                      distillation and
                                      Titration.
                                     Block digester,         ......................  .....................  .....................  See footnote.\40\
                                      followed by Auto
                                      distillation and
                                      Nesslerization.
                                     Block Digester,         ......................  .....................  .....................  See footnote.\41\
                                      followed by Flow
                                      injection gas
                                      diffusion
                                      (distillation not
                                      required).

                                     Digestion with          ......................  .....................  .....................  Hach 10242.\76\
                                      peroxdisulfate,
                                      followed by
                                      Spectrophotometric
                                      (2,6-dimethyl phenol).
                                     Digestion with          ......................  .....................  .....................  NCASI TNTP
                                      persulfate, followed                                                                          W10900.\77\
                                      by Colorimetric.
32. Lead--Total,\4\ mg/L...........  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration    ......................  3111 B-2019 or 3111 C- D3559-15 (A or B)....  974.27,\3\ I-3399-
                                      \36\.                                           2019.                                         85.\2\
                                     AA furnace............  ......................  3113 B-2020..........  D3559-15 (D).........  I-4403-89.\51\
                                     STGFAA................  200.9, Rev. 2.2 (1994)
                                     ICP/AES \36\..........  200.5, Rev. 4.2         3120 B-2020..........  D1976-20.............  I-4471-97.\50\
                                                              (2003); \68\ 200.7,
                                                              Rev. 4.4 (1994).
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14,\3\ I-4472-
                                                                                97.\81\
                                     DCP \36\..............  ......................  .....................  D4190-15.............  See footnote.\34\
                                     Voltammetry \11\......  ......................  .....................  D3559-15 (C).........
                                     Colorimetric            ......................  3500-Pb B-2020.......
                                      (Dithizone).
33. Magnesium--Total,\4\ mg/L......  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration..  ......................  3111 B-2019..........  D511-14 (B)..........  974.27,\3\ I-3447-
                                                                                85.\2\
                                     ICP/AES...............  200.5, Rev. 4.2         3120 B-2020..........  D1976-20.............  I-4471-97.\50\
                                                              (2003); \68\ 200.7,
                                                              Rev. 4.4 (1994).
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14.\3\
                                     DCP...................  ......................  .....................  .....................  See footnote.\34\
                                     Ion Chromatography....  ......................  .....................  D6919-17.............
34. Manganese--Total,\4\ mg/L......  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration    ......................  3111 B-2019 or 3111 C- D858-17 (A or B).....  974.27,\3\ I-3454-
                                      \36\.                                           2019.                                         85.\2\
                                     AA furnace............  ......................  3113 B-2020..........  D858-17 (C)..........
                                     STGFAA................  200.9, Rev. 2.2 (1994)
                                     ICP/AES \36\..........  200.5, Rev. 4.2         3120 B-2020..........  D1976-20.............  I-4471-97.\50\
                                                              (2003); \68\ 200.7,
                                                              Rev. 4.4 (1994).
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14,\3\ I-4472-
                                                                                97.\81\
                                     DCP \36\..............  ......................  .....................  D4190-15.............  See footnote.\34\
                                     Colorimetric            ......................  3500-Mn B-2020.......  .....................  920.203.\3\
                                      (Persulfate).
                                     Colorimetric            ......................  .....................  .....................  See footnote.\23\
                                      (Periodate).
35. Mercury--Total, mg/L...........  Cold vapor, Manual....  245.1, Rev. 3.0 (1994)  3112 B-2020..........  D3223-17.............  977.22,\3\ I-3462-
                                                                                85.\2\
                                     Cold vapor, Automated.  245.2 (Issued 1974)
                                                              \1\.
                                     Cold vapor atomic       245.7 Rev. 2.0 (2005)   .....................  .....................  I-4464-01.\71\
                                      fluorescence            \17\.
                                      spectrometry (CVAFS).
                                     Purge and Trap CVAFS..  1631E \43\............
36. Molybdenum--Total,\4\ mg/L.....  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration..  ......................  3111 D-2019..........  .....................  I-3490-85.\2\
                                     AA furnace............  ......................  3113 B-2020..........  .....................  I-3492-96.\47\
                                     ICP/AES...............  200.7, Rev. 4.4 (1994)  3120 B-2020..........  D1976-20.............  I-4471-97.\50\

                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14,\3\ I-4472-
                                                                                97.\81\
                                     DCP...................  ......................  .....................  .....................  See footnote.\34\
37. Nickel--Total,\4\ mg/L.........  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration    ......................  3111 B-2019 or 3111 C- D1886-14 (A or B)....  I-3499-85.\2\
                                      \36\.                                           2019.
                                     AA furnace............  ......................  3113 B-2020..........  D1886-14 (C).........  I-4503-89.\51\
                                     STGFAA................  200.9, Rev. 2.2 (1994)
                                     ICP/AES \36\..........  200.5, Rev. 4.2         3120 B-2020..........  D1976-20.............  I-4471-97.\50\
                                                              (2003); \68\ 200.7,
                                                              Rev. 4.4 (1994).
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14,\3\ I-4020-
                                                                                05,\70\ I-4472-
                                                                                97.\81\
                                     DCP \36\..............  ......................  .....................  D4190-15.............  See footnote.\34\
38. Nitrate (as N), mg/L...........  Ion Chromatography....  300.0, Rev. 2.1 (1993)  4110 B-2020 or C-2020  D4327-17.............  993.30.\3\
                                                              and 300.1, Rev. 1.0
                                                              (1997).
                                     CIE/UV................  ......................  4140 B-2020..........  D6508-15.............  D6508, Rev. 2.\54\
                                     Ion Selective           ......................  4500-NO3- D-2019.....
                                      Electrode.
                                     Colorimetric (Brucine   352.1 (Issued 1971)     .....................  .....................  973.50,\3\ 419D,\86\
                                      sulfate).               \1\.                                                                  p. 28.\9\
                                     Spectrophotometric      ......................  .....................  .....................  Hach 10206.\75\
                                      (2,6-dimethylphenol).
                                     Nitrate-nitrite N
                                      minus Nitrite N (See
                                      parameters 39 and 40).
39. Nitrate-nitrite (as N), mg/L...  Cadmium reduction,      ......................  4500-NO3- E-2019.....  D3867-16 (B).........
                                      Manual.
                                     Cadmium reduction,      353.2, Rev. 2.0 (1993)  4500-NO3- F-2019 or    D3867-16 (A).........  I-2545-90.\51\
                                      Automated.                                      4500-NO3- I-2019.
                                     Automated hydrazine...  ......................  4500-NO3- H-2019.....
                                     Reduction/Colorimetric  ......................  .....................  .....................  See footnote.\62\
                                     Ion Chromatography....  300.0, Rev. 2.1 (1993)  4110 B-2020 or C-2020  D4327-17.............  993.30.\3\
                                                              and 300.1, Rev. 1.0
                                                              (1997).
                                     CIE/UV................  ......................  4140 B-2020..........  D6508-15.............  D6508, Rev. 2.\54\
                                     Enzymatic reduction,    ......................  .....................  D7781-14.............  I-2547-11,\72\ I-2548-
                                      followed by automated                                                                         11,\72\ N07-
                                      colorimetric                                                                                0003.\73\
                                      determination.
                                     Enzymatic reduction,    ......................  4500-NO3- J-2018.....
                                      followed by manual
                                      colorimetric
                                      determination.
                                     Spectrophotometric      ......................  .....................  .....................  Hach 10206.\75\
                                      (2,6-dimethylphenol).
40. Nitrite (as N), mg/L...........  Spectrophotometric:     ......................  4500-NO2- B-2021.....  .....................  See footnote.\25\
                                      Manual.
                                     Automated               ......................  .....................  .....................  I-4540-85,\2\ See
                                      (Diazotization).                                                                              footnote.\62\ I-2540-
                                                                                90.\80\
                                     Automated (*bypass      353.2, Rev. 2.0 (1993)  4500-NO3- F-2019 4500- D3867-16 (A).........  I-4545-85.\2\
                                      cadmium reduction).                             NO3- I-2019.
                                     Manual (*bypass         ......................  4500-NO3- E-2019,      D3867-16 (B).........
                                      cadmium or enzymatic                            4500-NO3- J-2018.
                                      reduction).
                                     Ion Chromatography....  300.0, Rev. 2.1 (1993)  4110 B-2020 or C-2020  D4327-17.............  993.30.\3\
                                                              and 300.1, Rev. 1.0
                                                              (1997).
                                     CIE/UV................  ......................  4140 B-2020..........  D6508-15.............  D6508, Rev. 2.\54\
                                     Automated (*bypass      ......................  .....................  D7781-14.............  I-2547-11,\72\ I-2548-
                                      Enzymatic reduction).                                                                         11,\72\ N07-
                                                                                0003.\73\

41. Oil and grease--Total            Hexane extractable      1664 Rev. A; 1664 Rev.  5520 B or G-2021 \38\
 recoverable, mg/L.                   material (HEM): n-      B \42\.
                                      Hexane extraction and
                                      gravimetry.
                                     Silica gel treated HEM  1664 Rev. A; 1664 Rev.  5520 B or G-2021 \38\
                                      (SGT-HEM): Silica gel   B \42\.                 and 5520 F-2021 \38\.
                                      treatment and
                                      gravimetry.
42. Organic carbon--Total (TOC), mg/ Combustion............  ......................  5310 B-2014..........  D7573-18a \e1\.......  973.47,\3\ p. 14 \24\
 L.
                                     Heated persulfate or    ......................  5310 C-2014 5310 D-    D4839-03(17).........  973.47,\3\ p. 14.\24\
                                      UV persulfate                                   2011.
                                      oxidation.
43. Organic nitrogen (as N), mg/L..  Total Kjeldahl N
                                      (Parameter 31) minus
                                      ammonia N (Parameter
                                      4).
44. Ortho-phosphate (as P), mg/L...  Ascorbic acid method:
                                     Automated.............  365.1, Rev. 2.0 (1993)  4500-P F-2021 or G-    .....................  973.56,\3\ I-4601-
                                                                                2021.                                         85,\2\ I-2601-
                                                                                90.\80\
                                     Manual, single-reagent  ......................  4500-P E-2021........  D515-88 (A)..........  973.55.\3\
                                     Manual, two-reagent...  365.3 (Issued 1978)
                                                              \1\.
                                     Ion Chromatography....  300.0, Rev. 2.1 (1993)  4110 B-2020 or C-2020  D4327-17.............  993.30.\3\
                                                              and 300.1, Rev. 1.0
                                                              (1997).
                                     CIE/UV................  ......................  4140 B-2020..........  D6508-15.............  D6508, Rev. 2.\54\
45. Osmium--Total,\4\ mg/L.........  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration..  ......................  3111 D-2019..........
                                     AA furnace............  252.2 (Issued 1978)
                                                              \1\.
46. Oxygen, dissolved, mg/L........  Winkler (Azide          ......................  4500-O (B-F)-2021....  D888-18 (A)..........  973.45B,\3\ I-1575-
                                      modification).                                                                                78.\8\
                                     Electrode.............  ......................  4500-O G-2021........  D888-18 (B)..........  I-1576-78.\8\
                                     Luminescence-Based      ......................  4500-O H-2021........  D888-18 (C)..........  See footnote.\63\ See
                                      Sensor.                                                                                footnote.\64\
47. Palladium--Total,\4\ mg/L......  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration..  ......................  3111 B-2019..........
                                     AA furnace............  253.2 (Issued 1978)
                                                              \1\.
                                     ICP/MS................  ......................  3125 B-2020..........
                                     DCP...................  ......................  .....................  .....................  See footnote.\34\
48. Phenols, mg/L..................  Manual                  420.1 (Rev. 1978) \1\.  5530 B-2021..........  D1783-01(12).........
                                      distillation,\26\
                                      followed by any of
                                      the following:.
                                     Colorimetric (4AAP)     420.1 (Rev. 1978) \1\.  5530 D-2021 \27\.....  D1783-01(12) (A or B)
                                      manual.
                                     Automated colorimetric  420.4 Rev. 1.0 (1993).
                                      (4AAP).
49. Phosphorus (elemental), mg/L...  Gas-liquid              ......................  .....................  .....................  See footnote.\28\
                                      chromatography.
50. Phosphorus--Total, mg/L........  Digestion,\20\          ......................  4500-P B (5)-2021....  .....................  973.55.\3\
                                      followed by any of
                                      the following:
                                     Manual................  365.3 (Issued 1978)     4500-P E-2021........  D515-88 (A)..........
                                                              \1\.
                                     Automated ascorbic      365.1 Rev. 2.0 (1993).  4500-P (F-H)-2021....  .....................  973.56,\3\ I-4600-
                                      acid reduction.                                                                               85.\2\
                                     ICP/AES \4\ \36\......  200.7, Rev. 4.4 (1994)  3120 B-2020..........  .....................  I-4471-97.\50\
                                     Semi-automated block    365.4 (Issued 1974)     .....................  D515-88 (B)..........  I-4610-91.\48\
                                      digestor (TKP           \1\.
                                      digestion).
                                     Digestion with          ......................  .....................  .....................  NCASI TNTP
                                      persulfate, followed                                                                          W10900.\77\
                                      by Colorimetric.
51. Platinum--Total,\4\ mg/L.......  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration..  ......................  3111 B-2019..........

                                     AA furnace............  255.2 (Issued 1978)
                                                              \1\.
                                     ICP/MS................  ......................  3125 B-2020..........
                                     DCP...................  ......................  .....................  .....................  See footnote.\34\
52. Potassium--Total,\4\ mg/L......  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration..  ......................  3111 B-2019..........  .....................  973.53,\3\ I-3630-
                                                                                85.\2\
                                     ICP/AES...............  200.7, Rev. 4.4 (1994)  3120 B-2020..........
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14.\3\
                                     Flame photometric.....  ......................  3500-K B-2020........
                                     Electrode.............  ......................  3500-K C-2020........
                                     Ion Chromatography....  ......................  .....................  D6919-17.............
53. Residue--Total, mg/L...........  Gravimetric, 103-       ......................  2540 B-2020..........  .....................  I-3750-85.\2\
                                      105[deg].
54. Residue--filterable, mg/L......  Gravimetric, 180[deg].  ......................  2540 C-2020..........  D5907-18 (B).........  I-1750-85.\2\
55. Residue--non-filterable (TSS),   Gravimetric, 103-       ......................  2540 D-2020..........  D5907-18 (A).........  I-3765-85.\2\
 mg/L.                                105[deg] post-washing
                                      of residue.
56. Residue--settleable, mg/L......  Volumetric (Imhoff      ......................  2540 F-2020..........
                                      cone), or gravimetric.
57. Residue--Volatile, mg/L........  Gravimetric, 550[deg].  160.4 (Issued 1971)     2540 E-2020..........  .....................  I-3753-85.\2\
                                                              \1\.
58. Rhodium--Total,\4\ mg/L........  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration,   ......................  3111 B-2019..........
                                      or.
                                     AA furnace............  265.2 (Issued 1978)
                                                              \1\.
                                     ICP/MS................  ......................  3125 B-2020..........
59. Ruthenium--Total,\4\ mg/L......  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration,   ......................  3111 B-2019..........
                                      or.
                                     AA furnace............  267.2 \1\.............
                                     ICP/MS................  ......................  3125 B-2020..........
60. Selenium--Total,\4\ mg/L.......  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA furnace............  ......................  3113 B-2020..........  D3859-15 (B).........  I-4668-98.\49\
                                     STGFAA................  200.9, Rev. 2.2 (1994)
                                     ICP/AES \36\..........  200.5, Rev 4.2 (2003);  3120 B-2020..........  D1976-20.............
                                                              \68\ 200.7, Rev. 4.4
                                                              (1994).
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14,\3\ I-4020-
                                                                                05,\70\ I-4472-
                                                                                97.\81\
                                     AA gaseous hydride....  ......................  3114 B-2020, or 3114   D3859-15 (A).........  I-3667-85.\2\
                                                                                C-2020.
61. Silica--Dissolved,\37\ mg/L....  0.45-micron filtration
                                      followed by any of
                                      the following:
                                     Colorimetric, Manual..  ......................  4500-SiO2 C-2021.....  D859-16..............  I-1700-85.\2\
                                     Automated               ......................  4500-SiO2 E-2021 or F- .....................  I-2700-85.\2\
                                      (Molybdosilicate).                              2021.
                                     ICP/AES...............  200.5, Rev. 4.2         3120 B-2020..........  .....................  I-4471-97.\50\
                                                              (2003); \68\ 200.7,
                                                              Rev. 4.4 (1994).
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14.\3\
62. Silver--Total,\4\ \31\ mg/L....  Digestion,\4\ \29\
                                      followed by any of
                                      the following:
                                     AA direct aspiration..  ......................  3111 B-2019 or 3111 C- .....................  974.27,\3\ p. 37,\9\
                                                                                2019.                                         I-3720-85.\2\
                                     AA furnace............  ......................  3113 B-2020..........  .....................  I-4724-89.\51\
                                     STGFAA................  200.9, Rev. 2.2 (1994)

                                     ICP/AES...............  200.5, Rev. 4.2         3120 B-2020..........  D1976-20.............  I-4471-97.\50\
                                                              (2003); \68\ 200.7,
                                                              Rev. 4.4 (1994).
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14,\3\ I-4472-
                                                                                97.\81\
                                     DCP...................  ......................  .....................  .....................  See footnote.\34\
63. Sodium--Total,\4\ mg/L.........  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration..  ......................  3111 B-2019..........  .....................  973.54,\3\ I-3735-
                                                                                85.\2\
                                     ICP/AES...............  200.5, Rev. 4.2         3120 B-2020..........  .....................  I-4471-97.\50\
                                                              (2003); \68\ 200.7,
                                                              Rev. 4.4 (1994).
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14.\3\
                                     DCP...................  ......................  .....................  .....................  See footnote.\34\
                                     Flame photometric.....  ......................  3500-Na B-2020.......
                                     Ion Chromatography....  ......................  .....................  D6919-17.............
64. Specific conductance, micromhos/ Wheatstone bridge.....  120.1 (Rev. 1982) \1\.  2510 B-2021..........  D1125-95(99) (A).....  973.40,\3\ I-2781-
 cm at 25 [deg]C.                                                                                85.\2\
65. Sulfate (as SO4), mg/L.........  Automated colorimetric  375.2, Rev. 2.0 (1993)  4500-SO42- F-2021 or
                                                                                G-2021.
                                     Gravimetric...........  ......................  4500-SO42- C-2021 or   .....................  925.54. \3\
                                                                                D-2021.
                                     Turbidimetric.........  ......................  4500-SO42- E-2021....  D516-16..............
                                     Ion Chromatography....  300.0, Rev. 2.1 (1993)  4110 B-2020 or C-2020  D4327-17.............  993.30,\3\ I-4020-
                                                              and 300.1, Rev. 1.0                                                   05.\70\
                                                              (1997).
                                     CIE/UV................  ......................  4140 B-2020..........  D6508-15.............  D6508, Rev. 2.\54\
66. Sulfide (as S), mg/L...........  Sample Pretreatment...  ......................  4500-S2- B, C-2021...
                                     Titrimetric (iodine)..  ......................  4500-S2- F-2021......  .....................  I-3840-85.\2\
                                     Colorimetric            ......................  4500-S2- D-2021......
                                      (methylene blue).
                                     Ion Selective           ......................  4500-S2- G-2021......  D4658-15.............
                                      Electrode.
67. Sulfite (as SO3), mg/L.........  Titrimetric (iodine-    ......................  4500-SO32- B-2021....
                                      iodate).
68. Surfactants, mg/L..............  Colorimetric            ......................  5540 C-2021..........  D2330-20.............
                                      (methylene blue).
69. Temperature, [deg]C............  Thermometric..........  ......................  2550 B-2010..........  .....................  See footnote.\32\
70. Thallium--Total,\4\ mg/L.......  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration..  ......................  3111 B-2019..........
                                     AA furnace............  279.2 (Issued 1978)     3113 B-2020..........
                                                              \1\.
                                     STGFAA................  200.9, Rev. 2.2 (1994)
                                     ICP/AES...............  200.7, Rev. 4.4 (1994)  3120 B-2020..........  D1976-20.............
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14,\3\ I-4471-
                                                                                97,\50\ I-4472-
                                                                                97.\81\
71. Tin--Total,\4\ mg/L............  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration..  ......................  3111 B-2019..........  .....................  I-3850-78.\8\
                                     AA furnace............  ......................  3113 B-2020..........
                                     STGFAA................  200.9, Rev. 2.2 (1994)
                                     ICP/AES...............  200.5, Rev. 4.2
                                                              (2003); \68\ 200.7,
                                                              Rev. 4.4 (1994).
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14.\3\
72. Titanium--Total,\4\ mg/L.......  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration..  ......................  3111 D-2019..........
                                     AA furnace............  283.2 (Issued 1978)
                                                              \1\.
                                     ICP/AES...............  200.7, Rev. 4.4 (1994)

                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14.\3\
                                     DCP...................  ......................  .....................  .....................  See footnote.\34\
73. Turbidity, NTU \53\............  Nephelometric.........  180.1, Rev. 2.0 (1993)  2130 B-2020..........  D1889-00.............  I-3860-85.\2\ See
                                                                                footnote.\65\ See
                                                                                footnote.\66\ See
                                                                                footnote.\67\
74. Vanadium--Total,\4\ mg/L.......  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration..  ......................  3111 D-2019..........
                                     AA furnace............  ......................  3113 B-2020..........  D3373-17.............
                                     ICP/AES...............  200.5, Rev. 4.2         3120 B-2020..........  D1976-20.............  I-4471-97.\50\
                                                              (2003); \68\ 200.7,
                                                              Rev. 4.4 (1994).
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14,\3\ I-4020-
                                                                                05.\70\
                                     DCP...................  ......................  .....................  D4190-15.............  See footnote.\34\
                                     Colorimetric (Gallic    ......................  3500-V B-2011........
                                      Acid).
75. Zinc--Total,\4\ mg/L...........  Digestion,\4\ followed
                                      by any of the
                                      following:
                                     AA direct aspiration    ......................  3111 B-2019 or 3111 C- D1691-17 (A or B)....  974.27,\3\ p. 37,\9\
                                      \36\.                                           2019.                                         I-3900-85.\2\
                                     AA furnace............  289.2 (Issued 1978)
                                                              \1\.
                                     ICP/AES \36\..........  200.5, Rev. 4.2         3120 B-2020..........  D1976-20.............  I-4471-97.\50\
                                                              (2003); \68\ 200.7,
                                                              Rev. 4.4 (1994).
                                     ICP/MS................  200.8, Rev. 5.4 (1994)  3125 B-2020..........  D5673-16.............  993.14,\3\ I-4020-
                                                                                05,\70\ I-4472-
                                                                                97.\81\
                                     DCP \36\..............  ......................  .....................  D4190-15.............  See footnote.\34\
                                     Colorimetric (Zincon).  ......................  3500 Zn B-2020.......  .....................  See footnote.\33\
76. Acid Mine Drainage.............  ......................  1627 \69\.............
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table IB Notes:
\1\ Methods for Chemical Analysis of Water and Wastes, EPA-600/4-79-020. Revised March 1983 and 1979, where applicable. U.S. EPA.
\2\ Methods for Analysis of Inorganic Substances in Water and Fluvial Sediments, Techniques of Water-Resource Investigations of the U.S. Geological
  Survey, Book 5, Chapter A1., unless otherwise stated. 1989. USGS.
\3\ Official Methods of Analysis of the Association of Official Analytical Chemists, Methods Manual, Sixteenth Edition, 4th Revision, 1998. AOAC
  International.
\4\ For the determination of total metals (which are equivalent to total recoverable metals) the sample is not filtered before processing. A digestion
  procedure is required to solubilize analytes in suspended material and to break down organic-metal complexes (to convert the analyte to a detectable
  form for colorimetric analysis). For non-platform graphite furnace atomic absorption determinations, a digestion using nitric acid (as specified in
  Section 4.1.3 of Methods for Chemical Analysis of Water and Wastes) is required prior to analysis. The procedure used should subject the sample to
  gentle acid refluxing, and at no time should the sample be taken to dryness. For direct aspiration flame atomic absorption (FLAA) determinations, a
  combination acid (nitric and hydrochloric acids) digestion is preferred, prior to analysis. The approved total recoverable digestion is described as
  Method 200.2 in Supplement I of ``Methods for the Determination of Metals in Environmental Samples'' EPA/600R-94/111, May 1994, and is reproduced in
  EPA Methods 200.7, 200.8, and 200.9 from the same Supplement. However, when using the gaseous hydride technique or for the determination of certain
  elements such as antimony, arsenic, selenium, silver, and tin by non-EPA graphite furnace atomic absorption methods, mercury by cold vapor atomic
  absorption, the noble metals and titanium by FLAA, a specific or modified sample digestion procedure may be required, and, in all cases the referenced
  method write-up should be consulted for specific instruction and/or cautions. For analyses using inductively coupled plasma-atomic emission
  spectrometry (ICP-AES), the direct current plasma (DCP) technique or EPA spectrochemical techniques (platform furnace AA, ICP-AES, and ICP-MS), use
  EPA Method 200.2 or an approved alternate procedure (e.g., CEM microwave digestion, which may be used with certain analytes as indicated in Table IB
  of this section); the total recoverable digestion procedures in EPA Methods 200.7, 200.8, and 200.9 may be used for those respective methods.
  Regardless of the digestion procedure, the results of the analysis after digestion procedure are reported as ``total'' metals.
\5\ Copper sulfate or other catalysts that have been found suitable may be used in place of mercuric sulfate.
\6\ Manual distillation is not required if comparability data on representative effluent samples are on file to show that this preliminary distillation
  step is not necessary; however, manual distillation will be required to resolve any controversies. In general, the analytical method should be
  consulted regarding the need for distillation. If the method is not clear, the laboratory may compare a minimum of 9 different sample matrices to
  evaluate the need for distillation. For each matrix, a matrix spike and matrix spike duplicate are analyzed both with and without the distillation
  step (for a total of 36 samples, assuming 9 matrices). If results are comparable, the laboratory may dispense with the distillation step for future
  analysis. Comparable is defined as <20% RPD for all tested matrices). Alternatively, the two populations of spike recovery percentages may be compared
  using a recognized statistical test.
\7\ Industrial Method Number 379-75 WE Ammonia, Automated Electrode Method, Technicon Auto Analyzer II. February 19, 1976. Bran & Luebbe Analyzing
  Technologies Inc.
\8\ The approved method is that cited in Methods for Determination of Inorganic Substances in Water and Fluvial Sediments, Techniques of Water-Resources
  Investigations of the U.S. Geological Survey, Book 5, Chapter A1. 1979. USGS.
\9\ American National Standard on Photographic Processing Effluents. April 2, 1975. American National Standards Institute.
\10\ In-Situ Method 1003-8-2009, Biochemical Oxygen Demand (BOD) Measurement by Optical Probe. 2009. In-Situ Incorporated.
\11\ The use of normal and differential pulse voltage ramps to increase sensitivity and resolution is acceptable.

\12\ Carbonaceous biochemical oxygen demand (CBOD5) must not be confused with the traditional BOD5 test method which measures ``total 5-day BOD.'' The
  addition of the nitrification inhibitor is not a procedural option but must be included to report the CBOD5 parameter. A discharger whose permit
  requires reporting the traditional BOD5 may not use a nitrification inhibitor in the procedure for reporting the results. Only when a discharger's
  permit specifically states CBOD5 is required can the permittee report data using a nitrification inhibitor.
\13\ OIC Chemical Oxygen Demand Method. 1978. Oceanography International Corporation.
\14\ Method 8000, Chemical Oxygen Demand, Hach Handbook of Water Analysis, 1979. Hach Company.
\15\ The back-titration method will be used to resolve controversy.
\16\ Orion Research Instruction Manual, Residual Chlorine Electrode Model 97-70. 1977. Orion Research Incorporated. The calibration graph for the Orion
  residual chlorine method must be derived using a reagent blank and three standard solutions, containing 0.2, 1.0, and 5.0 mL 0.00281 N potassium
  iodate/100 mL solution, respectively.
\17\ Method 245.7, Mercury in Water by Cold Vapor Atomic Fluorescence Spectrometry, EPA-821-R-05-001. Revision 2.0, February 2005. US EPA.
\18\ National Council of the Paper Industry for Air and Stream Improvement (NCASI) Technical Bulletin 253 (1971) and Technical Bulletin 803, May 2000.
\19\ Method 8506, Bicinchoninate Method for Copper, Hach Handbook of Water Analysis. 1979. Hach Company.
\20\ When using a method with block digestion, this treatment is not required.
\21\ Industrial Method Number 378-75WA, Hydrogen ion (pH) Automated Electrode Method, Bran & Luebbe (Technicon) Autoanalyzer II. October 1976. Bran &
  Luebbe Analyzing Technologies.
\22\ Method 8008, 1,10-Phenanthroline Method using FerroVer Iron Reagent for Water. 1980. Hach Company.
\23\ Method 8034, Periodate Oxidation Method for Manganese, Hach Handbook of Wastewater Analysis. 1979. Hach Company.
\24\ Methods for Analysis of Organic Substances in Water and Fluvial Sediments, Techniques of Water-Resources Investigations of the U.S. Geological
  Survey, Book 5, Chapter A3, (1972 Revised 1987). 1987. USGS.
\25\ Method 8507, Nitrogen, Nitrite-Low Range, Diazotization Method for Water and Wastewater. 1979. Hach Company.
\26\ Just prior to distillation, adjust the sulfuric-acid-preserved sample to pH 4 with 1 + 9 NaOH.
\27\ The colorimetric reaction must be conducted at a pH of 10.0  0.2.
\28\ Addison, R.F., and R.G. Ackman. 1970. Direct Determination of Elemental Phosphorus by Gas-Liquid Chromatography, Journal of Chromatography,
  47(3):421-426.
\29\ Approved methods for the analysis of silver in industrial wastewaters at concentrations of 1 mg/L and above are inadequate where silver exists as
  an inorganic halide. Silver halides such as the bromide and chloride are relatively insoluble in reagents such as nitric acid but are readily soluble
  in an aqueous buffer of sodium thiosulfate and sodium hydroxide to pH of 12. Therefore, for levels of silver above 1 mg/L, 20 mL of sample should be
  diluted to 100 mL by adding 40 mL each of 2 M Na2S2O3 and NaOH. Standards should be prepared in the same manner. For levels of silver below 1 mg/L the
  approved method is satisfactory.
\30\ The use of EDTA decreases method sensitivity. Analysts may omit EDTA or replace with another suitable complexing reagent provided that all method-
  specified quality control acceptance criteria are met.
\31\ For samples known or suspected to contain high levels of silver (e.g., in excess of 4 mg/L), cyanogen iodide should be used to keep the silver in
  solution for analysis. Prepare a cyanogen iodide solution by adding 4.0 mL of concentrated NH4OH, 6.5 g of KCN, and 5.0 mL of a 1.0 N solution of I2
  to 50 mL of reagent water in a volumetric flask and dilute to 100.0 mL. After digestion of the sample, adjust the pH of the digestate to >7 to prevent
  the formation of HCN under acidic conditions. Add 1 mL of the cyanogen iodide solution to the sample digestate and adjust the volume to 100 mL with
  reagent water (NOT acid). If cyanogen iodide is added to sample digestates, then silver standards must be prepared that contain cyanogen iodide as
  well. Prepare working standards by diluting a small volume of a silver stock solution with water and adjusting the pH >7 with NH4OH. Add 1 mL of the
  cyanogen iodide solution and let stand 1 hour. Transfer to a 100-mL volumetric flask and dilute to volume with water.
\32\ ``Water Temperature-Influential Factors, Field Measurement and Data Presentation,'' Techniques of Water-Resources Investigations of the U.S.
  Geological Survey, Book 1, Chapter D1. 1975. USGS.
\33\ Method 8009, Zincon Method for Zinc, Hach Handbook of Water Analysis, 1979. Hach Company.
\34\ Method AES0029, Direct Current Plasma (DCP) Optical Emission Spectrometric Method for Trace Elemental Analysis of Water and Wastes. 1986-Revised
  1991. Thermo Jarrell Ash Corporation.
\35\ In-Situ Method 1004-8-2009, Carbonaceous Biochemical Oxygen Demand (CBOD) Measurement by Optical Probe. 2009. In-Situ Incorporated.
\36\ Microwave-assisted digestion may be employed for this metal, when analyzed by this methodology. Closed Vessel Microwave Digestion of Wastewater
  Samples for Determination of Metals. April 16, 1992. CEM Corporation.
\37\ When determining boron and silica, only plastic, PTFE, or quartz laboratory ware may be used from start until completion of analysis.
\38\ Only use n-hexane (n-Hexane--85% minimum purity, 99.0% min. saturated C6 isomers, residue less than 1 mg/L) extraction solvent when determining Oil
  and Grease parameters--Hexane Extractable Material (HEM), or Silica Gel Treated HEM (analogous to EPA Methods 1664 Rev. A and 1664 Rev. B). Use of
  other extraction solvents is prohibited.
\39\ Method PAI-DK01, Nitrogen, Total Kjeldahl, Block Digestion, Steam Distillation, Titrimetric Detection. Revised December 22, 1994. OI Analytical.
\40\ Method PAI-DK02, Nitrogen, Total Kjeldahl, Block Digestion, Steam Distillation, Colorimetric Detection. Revised December 22, 1994. OI Analytical.
\41\ Method PAI-DK03, Nitrogen, Total Kjeldahl, Block Digestion, Automated FIA Gas Diffusion. Revised December 22, 1994. OI Analytical.
\42\ Method 1664 Rev. B is the revised version of EPA Method 1664 Rev. A. U.S. EPA. February 1999, Revision A. Method 1664, n-Hexane Extractable
  Material (HEM; Oil and Grease) and Silica Gel Treated n-Hexane Extractable Material (SGT-HEM; Non-polar Material) by Extraction and Gravimetry. EPA-
  821-R-98-002. U.S. EPA. February 2010, Revision B. Method 1664, n-Hexane Extractable Material (HEM; Oil and Grease) and Silica Gel Treated n-Hexane
  Extractable Material (SGT-HEM; Non-polar Material) by Extraction and Gravimetry. EPA-821-R-10-001.
\43\ Method 1631, Revision E, Mercury in Water by Oxidation, Purge and Trap, and Cold Vapor Atomic Fluorescence Spectrometry, EPA-821-R-02-019. Revision
  E. August 2002, U.S. EPA. The application of clean techniques described in EPA's Method 1669: Sampling Ambient Water for Trace Metals at EPA Water
  Quality Criteria Levels, EPA-821-R-96-011, are recommended to preclude contamination at low-level, trace metal determinations.
\44\ Method OIA-1677-09, Available Cyanide by Ligand Exchange and Flow Injection Analysis (FIA). 2010. OI Analytical.
\45\ Open File Report 00-170, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory--Determination of Ammonium Plus
  Organic Nitrogen by a Kjeldahl Digestion Method and an Automated Photometric Finish that Includes Digest Cleanup by Gas Diffusion. 2000. USGS.
\46\ Open File Report 93-449, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory--Determination of Chromium in Water by
  Graphite Furnace Atomic Absorption Spectrophotometry. 1993. USGS.
\47\ Open File Report 97-198, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory--Determination of Molybdenum by
  Graphite Furnace Atomic Absorption Spectrophotometry. 1997. USGS.
\48\ Open File Report 92-146, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory--Determination of Total Phosphorus by
  Kjeldahl Digestion Method and an Automated Colorimetric Finish That Includes Dialysis. 1992. USGS.
\49\ Open File Report 98-639, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory--Determination of Arsenic and Selenium
  in Water and Sediment by Graphite Furnace-Atomic Absorption Spectrometry. 1999. USGS.
\50\ Open File Report 98-165, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory--Determination of Elements in Whole-
  water Digests Using Inductively Coupled Plasma-Optical Emission Spectrometry and Inductively Coupled Plasma-Mass Spectrometry. 1998. USGS.
\51\ Open File Report 93-125, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory--Determination of Inorganic and
  Organic Constituents in Water and Fluvial Sediments. 1993. USGS.

\52\ Unless otherwise indicated, all EPA methods, excluding EPA Method 300.1, are published in U.S. EPA. May 1994. Methods for the Determination of
  Metals in Environmental Samples, Supplement I, EPA/600/R-94/111; or U.S. EPA. August 1993. Methods for the Determination of Inorganic Substances in
  Environmental Samples, EPA/600/R-93/100. EPA Method 300.1 is U.S. EPA. Revision 1.0, 1997, including errata cover sheet April 27, 1999. Determination
  of Inorganic Ions in Drinking Water by Ion Chromatography.
\53\ Styrene divinyl benzene beads (e.g., AMCO-AEPA-1 or equivalent) and stabilized formazin (e.g., Hach StablCal \TM\ or equivalent) are acceptable
  substitutes for formazin.
\54\ Method D6508-15, Test Method for Determination of Dissolved Inorganic Anions in Aqueous Matrices Using Capillary Ion Electrophoresis and Chromate
  Electrolyte. 2015. ASTM.
\55\ Kelada-01, Kelada Automated Test Methods for Total Cyanide, Acid Dissociable Cyanide, and Thiocyanate, EPA 821-B-01-009, Revision 1.2, August 2001.
  US EPA. Note: A 450-W UV lamp may be used in this method instead of the 550-W lamp specified if it provides performance within the quality control
  (QC) acceptance criteria of the method in a given instrument. Similarly, modified flow cell configurations and flow conditions may be used in the
  method, provided that the QC acceptance criteria are met.
\56\ 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 2.2, March 2005. Lachat Instruments.
\57\ When using sulfide removal test procedures described in EPA Method 335.4, reconstitute particulate that is filtered with the sample prior to
  distillation.
\58\ Unless otherwise stated, if the language of this table specifies a sample digestion and/or distillation ``followed by'' analysis with a method,
  approved digestion and/or distillation are required prior to analysis.
\59\ Samples analyzed for available cyanide using OI Analytical method OIA-1677-09 or ASTM method D6888-16 that contain particulate matter may be
  filtered only after the ligand exchange reagents have been added to the samples, because the ligand exchange process converts complexes containing
  available cyanide to free cyanide, which is not removed by filtration. Analysts are further cautioned to limit the time between the addition of the
  ligand exchange reagents and sample filtration to no more than 30 minutes to preclude settling of materials in samples.
\60\ Analysts should be aware that pH optima and chromophore absorption maxima might differ when phenol is replaced by a substituted phenol as the color
  reagent in Berthelot Reaction (``phenol-hypochlorite reaction'') colorimetric ammonium determination methods. For example, when phenol is used as the
  color reagent, pH optimum and wavelength of maximum absorbance are about 11.5 and 635 nm, respectively--see, Patton, C.J. and S.R. Crouch. March 1977.
  Anal. Chem. 49:464-469. These reaction parameters increase to pH > 12.6 and 665 nm when salicylate is used as the color reagent--see, Krom, M.D. April
  1980. The Analyst 105:305-316.
\61\ If atomic absorption or ICP instrumentation is not available, the aluminon colorimetric method detailed in the 19th Edition of Standard Methods for
  the Examination of Water and Wastewater may be used. This method has poorer precision and bias than the methods of choice.
\62\ Easy (1-Reagent) Nitrate Method, Revision November 12, 2011. Craig Chinchilla.
\63\ Hach Method 10360, Luminescence Measurement of Dissolved Oxygen in Water and Wastewater and for Use in the Determination of BOD5 and CBOD5.
  Revision 1.2, October 2011. Hach Company. This method may be used to measure dissolved oxygen when performing the methods approved in Table IB of this
  section for measurement of biochemical oxygen demand (BOD) and carbonaceous biochemical oxygen demand (CBOD).
\64\ In-Situ Method 1002-8-2009, Dissolved Oxygen (DO) Measurement by Optical Probe. 2009. In-Situ Incorporated.
\65\ Mitchell Method M5331, Determination of Turbidity by Nephelometry. Revision 1.0, July 31, 2008. Leck Mitchell.
\66\ Mitchell Method M5271, Determination of Turbidity by Nephelometry. Revision 1.0, July 31, 2008. Leck Mitchell.
\67\ Orion Method AQ4500, Determination of Turbidity by Nephelometry. Revision 5, March 12, 2009. Thermo Scientific.
\68\ EPA Method 200.5, Determination of Trace Elements in Drinking Water by Axially Viewed Inductively Coupled Plasma-Atomic Emission Spectrometry, EPA/
  600/R-06/115. Revision 4.2, October 2003. US EPA.
\69\ Method 1627, Kinetic Test Method for the Prediction of Mine Drainage Quality, EPA-821-R-09-002. December 2011. US EPA.
\70\ Techniques and Methods Book 5-B1, Determination of Elements in Natural-Water, Biota, Sediment and Soil Samples Using Collision/Reaction Cell
  Inductively Coupled Plasma-Mass Spectrometry, Chapter 1, Section B, Methods of the National Water Quality Laboratory, Book 5, Laboratory Analysis,
  2006. USGS.
\71\ Water-Resources Investigations Report 01-4132, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory--Determination
  of Organic Plus Inorganic Mercury in Filtered and Unfiltered Natural Water with Cold Vapor-Atomic Fluorescence Spectrometry, 2001. USGS.
\72\ USGS Techniques and Methods 5-B8, Chapter 8, Section B, Methods of the National Water Quality Laboratory, Book 5, Laboratory Analysis, 2011 USGS.
\73\ NECi Method N07-0003, ``Nitrate Reductase Nitrate-Nitrogen Analysis,'' Revision 9.0, March 2014, The Nitrate Elimination Co., Inc.
\74\ Timberline Instruments, LLC Method Ammonia-001, ``Determination of Inorganic Ammonia by Continuous Flow Gas Diffusion and Conductivity Cell
  Analysis,'' June 2011, Timberline Instruments, LLC.
\75\ Hach Company Method 10206, ``Spectrophotometric Measurement of Nitrate in Water and Wastewater,'' Revision 2.1, January 2013, Hach Company.
\76\ Hach Company Method 10242, ``Simplified Spectrophotometric Measurement of Total Kjeldahl Nitrogen in Water and Wastewater,'' Revision 1.1, January
  2013, Hach Company.
\77\ National Council for Air and Stream Improvement (NCASI) Method TNTP-W10900, ``Total (Kjeldahl) Nitrogen and Total Phosphorus in Pulp and Paper
  Biologically Treated Effluent by Alkaline Persulfate Digestion,'' June 2011, National Council for Air and Stream Improvement, Inc.
\78\ The pH adjusted sample is to be adjusted to 7.6 for NPDES reporting purposes.
\79\ I-2057-85 U.S. Geological Survey Techniques of Water-Resources Investigations, Book 5, Chap. A11989, Methods for Determination of Inorganic
  Substances in Water and Fluvial Sediments, 1989.
\80\ Methods I-2522-90, I-2540-90, and I-2601-90 U.S. Geological Survey Open-File Report 93-125, Methods of Analysis by the U.S. Geological Survey
  National Water Quality Laboratory--Determination of Inorganic and Organic Constituents in Water and Fluvial Sediments, 1993.
\81\ Method I-1472-97, U.S. Geological Survey Open-File Report 98-165, Methods of Analysis by the U.S. Geological Survey National Water Quality
  Laboratory--Determination of Inorganic and Organic Constituents in Water and Fluvial Sediments, 1998.
\82\ FIAlab Instruments, Inc. Method FIAlab 100, ``Determination of Inorganic Ammonia by Continuous Flow Gas Diffusion and Fluorescence Detector
  Analysis'', April 4, 2018, FIAlab Instruments, Inc.
\83\ MACHEREY-NAGEL GmbH and Co. Method 036/038 NANOCOLOR[supreg] COD LR/HR, ``Spectrophotometric Measurement of Chemical Oxygen Demand in Water and
  Wastewater'', Revision 1.5, May 2018, MACHEREY-NAGEL GmbH and Co. KG.
\84\ Please refer to the following applicable Quality Control Sections: Part 2000 Methods, Physical and Aggregate Properties 2020 (2021); Part 3000
  Methods, Metals, 3020 (2021); Part 4000 Methods, Inorganic Nonmetallic Constituents, 4020 (2022); Part 5000 Methods, and Aggregate Organic
  Constituents, 5020 (2022). These Quality Control Standards are available for download at www.standardmethods.org at no charge.
\85\ Each laboratory may establish its own control limits by performing at least 25 glucose-glutamic acid (GGA) checks over several weeks or months and
  calculating the mean and standard deviation. The laboratory may then use the mean  3 standard deviations as the control limit for future
  GGA checks. However, GGA acceptance criteria can be no wider than 198  30.5 mg/L for BOD5. GGA acceptance criteria for CBOD must be either
  198  30.5 mg/L, or the lab may develop control charts under the following conditions: dissolved oxygen uptake from the seed contribution
  is between 0.6-1.0 mg/L; control charts are performed on at least 25 GGA checks with three standard deviations from the derived mean; the RSD must not
  exceed 7.5%; and any single GGA value cannot be less than 150 mg/L or higher than 250 mg/L.
\86\ The approved method is that cited in Standard Methods for the Examination of Water and Wastewater, 14th Edition, 1976.

                                     Table IC--List of Approved Test Procedures for Non-Pesticide Organic Compounds
--------------------------------------------------------------------------------------------------------------------------------------------------------
           Parameter \1\                     Method                EPA \2\ \7\       Standard methods \15\           ASTM                  Other
--------------------------------------------------------------------------------------------------------------------------------------------------------
1. Acenaphthene....................  GC....................  610...................
                                     GC/MS.................  625.1, 1625B..........  6410 B-2020..........  .....................  See footnote,\9\ p.
                                                                                27.
                                     HPLC..................  610...................  6440 B-2021..........  D4657-92 (98)........
2. Acenaphthylene..................  GC....................  610...................
                                     GC/MS.................  625.1, 1625B..........  6410 B-2020..........  .....................  See footnote,\9\ p.
                                                                                27.
                                     HPLC..................  610...................  6440 B-2021..........  D4657-92 (98)........
3. Acrolein........................  GC....................  603...................
                                     GC/MS.................  624.1,\4\ 1624B.......
4. Acrylonitrile...................  GC....................  603...................
                                     GC/MS.................  624.1,\4\ 1624B.......  .....................  .....................  O-4127-96.\13\
5. Anthracene......................  GC....................  610...................
                                     GC/MS.................  625.1, 1625B..........  6410 B-2020..........  .....................  See footnote,\9\ p.
                                                                                27.
                                     HPLC..................  610...................  6440B-2021...........  D4657-92 (98)........
6. Benzene.........................  GC....................  602...................  6200 C-2020..........
                                     GC/MS.................  624.1, 1624B..........  6200 B-2020..........  .....................  O-4127-96,\13\ O-4436-
                                                                                16.\14\
7. Benzidine.......................  Spectro-photometric...  ......................  .....................  .....................  See footnote,\3\ p.
                                                                                1.
                                     GC/MS.................  625.1,\5\ 1625B.......  6410 B-2020..........
                                     HPLC..................  605...................
8. Benzo(a)anthracene..............  GC....................  610...................
                                     GC/MS.................  625.1, 1625B..........  6410 B-2020..........  .....................  See footnote,\9\ p.
                                                                                27.
                                     HPLC..................  610...................  6440 B-2021..........  D4657-92 (98)........
9. Benzo(a)pyrene..................  GC....................  610...................
                                     GC/MS.................  625.1, 1625B..........  6410 B-2020..........  .....................  See footnote,\9\ p.
                                                                                27.
                                     HPLC..................  610...................  6440 B-2021..........  D4657-92 (98)........
10. Benzo(b)fluoranthene...........  GC....................  610...................
                                     GC/MS.................  625.1, 1625B..........  6410 B-2020..........  .....................  See footnote,\9\ p.
                                                                                27.
                                     HPLC..................  610...................  6440 B-2021..........  D4657-92 (98)........
11. Benzo(g,h,i)perylene...........  GC....................  610...................
                                     GC/MS.................  625.1, 1625B..........  6410 B-2020..........  .....................  See footnote,\9\ p.
                                                                                27.
                                     HPLC..................  610...................  6440 B-2021..........  D4657-92 (98)........
12. Benzo(k)fluoranthene...........  GC....................  610...................
                                     GC/MS.................  625.1, 1625B..........  6410 B-2020..........  .....................  See footnote,\9\ p.
                                                                                27.
                                     HPLC..................  610...................  6440 B-2021..........  D4657-92 (98)........
13. Benzyl chloride................  GC....................  ......................  .....................  .....................  See footnote,\3\ p.
                                                                                130.
                                     GC/MS.................  ......................  .....................  .....................  See footnote,\6\ p.
                                                                                S102.
14. Butyl benzyl phthalate.........  GC....................  606...................
                                     GC/MS.................  625.1, 1625B..........  6410 B-2020..........  .....................  See footnote,\9\ p.
                                                                                27.
15. bis(2-Chloroethoxy) methane....  GC....................  611...................
                                     GC/MS.................  625.1, 1625B..........  6410 B-2020..........  .....................  See footnote,\9\ p.
                                                                                27.
16. bis(2-Chloroethyl) ether.......  GC....................  611...................
                                     GC/MS.................  625.1, 1625B..........  6410 B-2020..........  .....................  See footnote,\9\ p.
                                                                                27.
17. bis(2-Ethylhexyl) phthalate....  GC....................  606...................
                                     GC/MS.................  625.1, 1625B..........  6410 B-2020..........  .....................  See footnote,\9\ p.