United States
                   Environmental Protection
                   Agency

   Cyanide Clarification of Free and Total

  Cyanide Analysis for Safe Drinking Water

          Act (SDWA) Compliance
Office of Water (MS-140)        EPA 815-B-16-012             August 2016

-------
Address questions concerning this document to:

Judith A. Brisbin, Ph.D.
U.S. EPA, Office of Ground Water and Drinking Water,
Technical Support Center
26 W. Martin Luther King Dr.
Cincinnati, OH 45268
(513) 569-7883
brisbin.judv@epa.gov

-------
Chemical Phase RuleV	1
Certification/Accreditation	1
Preservation	2
  Excerpt from Table in 40 CFR 141.23 (k)(2)	2
Water Treatment and Cyanide	2
PE Acceptance Limits	2
  Excerpt from Table in 40 CFR 141.23 (k)(3)(ii)	2
Maximum Contaminant Level (MCL)	2
  Excerpt from Table in 40 CFR 141.62 (b)	3
Methodology	3
  Excerpt from Table in 40 CFR 141.23 (a)(4)(i)	3
  Excerpt from Table in 40 CFR 141.23 (k)(l)	4
  Excerpt from Table in Appendix A to Subpart Cof Part 141	5
Modified Methodologies and Methods for Total and Free Cyanide Table	6
  Modified Table for Total Cyanide	7
  Modified Table for Free Cyanide	8
  Modified Table for Total Cyanide (clean version)	9
  Modified Table for Free Cyanide (clean version)	10

-------
c                 •    •

57 FR 31776-31849 Chemical Phase Rule V (Vol. 57, No. 138, July 17, 1992) - States the following: Total
cyanide methods are allowed for screening, the Maximum Contaminant Level (MCL)/Maximum
Contaminant Level Goal (MCLG) applies to free cyanide, the agency definition of "free" is amenable to
chlorination, and the MCL and MCLG is 0.2 ppm (mg/L).

    •   Cyanide is regulated as Free Cyanide (Table in 40 CFR 141.62(b) defines an MCL of 0.2 mg/L for
       Cyanide (as free cyanide)), but Total Cyanide methods are allowed for screening. The Total
       Cyanide screening methods are easier, faster and cheaper than the Free Cyanide methods.
           o  If the total cyanide is <0.2 mg CN"/L, you  can report free cyanide as <0.2 mg/L;
           o  If the total cyanide is >0.2 mg CN"/L, determine free cyanide by an approved free
              cyanide method.

    •   The Agency has regulated FREE CYANIDE as Cyanides Amenable to Chlorination, and set the MCL
       based on Free Cyanide.

    •   Cyanides amenable to chlorination provides a conservative estimate of toxicity because, in
       addition to free cyanide, it recovers some weak acid dissociable metal cyanide complexes that
       may or may not actually release free cyanide in the environment.
Note: A good resource for definitions of cyanide terms can be found in ASTM D 6696-05.

                 "    red nation

The methods for free and total cyanide are listed in Table 40 CFR 141.23 (k)(l).  Only the approved
methods may be used:
       Analysis for the following contaminants shall be conducted in accordance with the methods in
       the following table, or the alternative methods listed in appendix A to subpart C of this part, or
       their equivalent as determined by EPA...
Free and total cyanide are part of the National Primary Drinking Water Regulations (NPDWRs) and 40
CFR 141.23 is referenced in 40 CFR 141.28(a) stating that laboratories analyzing compliance samples
must be certified/accredited as follows:
       For the purpose of determining compliance with §141.21 through 141.27, 141.30, 141.40,
       141.74,141.89 and 141.402, samples may be considered only if they have been analyzed by a
       laboratory certified by the State...

-------
Preservation
Excerpt from Table in 40 CFR 141.23 (k)(2)
Contaminant
Cyanide
Preservative1
4"C, NaOH
Container2
PorG
Time3
14 days
1  For cyanide determinations samples must be adjusted with sodium hydroxide to pH 12 at the time of collection. When
  chilling is indicated the sample must be shipped and stored at 4 °C or less ...
2  P = plastic, hard or soft; G=glass, hard or soft.
3  In all cases samples should be analyzed as soon after collection as possible. Follow additional (if any) information on
  preservation, containers or holding times that is specified in method.
Summary:     Container:            Plastic or Glass
              Preservation:         NaOH to pH  12
                                   4°C
              Holding Time:         14 days

Water Treatment and  Cyanide

The oxidative effects of disinfection (chlorination and/or most of the alternatives like ozone, chlorine
dioxide, etc...) can chemically alter the sample matrix and these oxidants may react with regulated
contaminants. This isn't limited to contaminants like  cyanide and glyphosate. Disinfection is an integral
component of treatment, primarily to control microbial contaminants, but regulated contaminants may
also be removed as a secondary benefit. Other forms of treatment like aeration or Granular Activated
Carbon (GAC) are specifically designed to remove regulated organic chemicals, and even though these
treatments are used, the  Public Water System (PWS) must still monitor for those contaminants.
Contaminants like cyanide (and glyphosate) are no different. The statements in some methods regarding
disinfectant reactivity with certain contaminants are  typically included in those methods to assist
laboratories and PWSs with interpreting data, not to  grant any allowance to the PWS to forgo
monitoring because of the expectation that the contaminant will no longer be measured in the treated
water. For example, microbial monitoring must still occur on the finished water even though the source
water is treated with chlorine as a disinfectant.

PE Acceptance  Limits

The Table in 40 CFR 141.23 (k)(3)(ii) (excerpt  shown below) lists the Performance Evaluation (PE)
Acceptance Limit for Cyanide as ± 25% at >0.1 mg/L.

Excerpt from Table in  40 CFR 141.23 (k)(3)(ii)
Contaminant
Cyanide
Acceptance
± 25% at >0
Limit
lmg/L
Maximum  Contaminant Level (MCL)
The Table in 40 CFR 141.62 (b) (excerpt shown below) lists a Maximum Contaminant Level (MCL) of 0.2
mg/L for Cyanide (as free Cyanide). Cyanide is therefore regulated as free cyanide.

-------
Excerpt from Table in 40 CFR 141.62 (b)
Contaminant
(13) Cyanide (as free Cyanide)
MCL (mg/L)
0.2
Methodology
Methodologies for Cyanide are shown in Tables in 40 CFR 141.23 (a)(4)(i), 40 CFR 141.23 (k)(l) and
Appendix A to Subpart C of Part 141. Excerpts from these Tables are shown below.
Excerpt from Table in 40 CFR 141.23 (a)(4)(i)
Contaminant
Cyanide






MCL (mg/L)
0.2






Methodology
Distillation, Spectrophotometric3
Distillation, Automated,
Spectrophotometric3
Distillation, Amenable,
Spectrophotometric4
Distillation, Selective Electrode34
UV, Distillation, Spectrophotometric9
Micro Distillation, Flow Injection,
Spectrophotometric3
Ligand Exchange with Amperometry4
Detection limit (mg/L)
0.02
0.005
0.02
0.05
0.0005
0.0006
0.0005
3 Screening method for total cyanides.
4 Measures "free" cyanides when distillation, digestion, or ligand exchange is omitted.
9 Measures total cyanides when UV-digestor [sic] is used, and "free" cyanides when UV-digestor [sic] is bypassed.
[Note: This table is primarily used in conjunction with Consumer Confidence Reports.]
The Table in 40 CFR 141.23 (a)(4)(i) has several footnotes that indicate:
    •   Screening methods for total cyanides have footnote 3.
    •   Free cyanide methods - with distillation, digestion or ligand exchange omitted - are indicated by
       footnote 4.
    •   There is one methodology associated with both footnotes 3 and 4 so it can be used to measure
       both free and total cyanides.
    •   UV, Distillation, Spectrophotometric, footnote 9,  is also approved to measure free and total
       cyanides. It measures total cyanides when the UV-digester is used and free cyanides when the
       UV-digester is bypassed.

-------
Excerpt from Table in 40 CFR 141.23 (k)(l)
Contaminant



12. Cyanide
















Methodology13



Manual Distillation
followed by
Spectrophotometric,
Amenable
Spectrophotometric
[sic] Manual
Spectrophotometric
[sic] Semi-automated
Selective Electrode

UV, Distillation,
Spectrophotometric
Micro Distillation, Flow
Injection,
Spectrophotometric
Ligand Exchange and
Amperometry21
EPA









335.4s










ASTM3



D2036-
98 A
D2036-
98 B
D2036-
98 A









D6888-
04
SM4
(18th,
19th
ed.)
4500-
CI\TC
4500-
CI\TG
4500-
CN-E


4500-
CI\TF







SM4
(20th
ed.)

4500-
CI\TC
4500-
CN-G
4500-
CN-E


4500-
CN-F







SM
Online22




4500-CN-
G-99
4500-CN-
E-99


4500-CN-
F-99







Other







I-3300-855





Kelada-
Ol17
QuikChem
10-204-
00-1-X18
OIA-1677,
DW20
3 Annual Book of ASTM Standards, ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428,
  http://www.astm.org.; Annual Book of ASTM Standards 1994, Vols. 11.01 and 11.02; Annual Book of ASTM Standards
  1996, Vols. 11.01 and 11.02; Annual Book of ASTM Standards 1999, Vols. 11.01 and 11.02; Annual Book of ASTM
  Standards 2003, Vols. 11.01 and 11.02.
4 Standard Methods for the Examination of Water and Wastewater, American Public Health Association, 800 I Street
  NW., Washington, DC 20001-3710; Standard Methods for the Examination of Water and Wastewater, 18th edition
  (1992); Standard Methods for the Examination of Water and Wastewater, 19th edition (1995); Standard Methods for
  the Examination of Water and Wastewater, 20th edition (1998).The following methods from this edition cannot be
  used: 3111 B, 3111 D, 3113 B, and 3114 B.
5 U.S. Geological Survey, Federal Center, Box 25286, Denver, CO 80225-0425; Methods for Analysis by the U.S.
  Geological Survey National Water Quality Laboratory—Determination of Inorganic and Organic Constituents in Water
  and Fluvial Sediment, Open File Report 93-125,1993; Techniques of Water Resources  Investigation of the U.S.
  Geological Survey, Book 5, Chapter A-l, 3rd edition, 1989.
6 "Methods for the Determination  of Inorganic Substances in Environmental Samples," EPA/600/R-93/100, August 1993.
  Available as Technical Report PB94-120821 at National Technical Information Service (NTIS), 5301 Shawnee Road,
  Alexandria, VA 22312. http://www.ntis.gov.
13
17The description for the Kelada-01 Method, "Kelada Automated Test Methods for Total Cyanide, Acid Dissociable
  Cyanide, And Thiocyanate," Revision 1.2, August 2001, EPA # 821-B-01-009 for cyanide is available from the National
  Technical Information Service (NTIS), PB 2001-108275, 5285 Port Royal  Road, Springfield, VA 22161. The toll free
  telephone number is 800-553-6847. 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.
18The description for the QuikChem Method 10-204-00-1-X, "Digestion and distillation of total cyanide in drinking and
  wastewaters using MICRO DIST and determination of cyanide by flow injection analysis," Revision 2.1, November 30,
  2000, for cyanide is available from Lachat Instruments, 6645 W. Mill Rd., Milwaukee, Wl  53218. Telephone: 414-358-
  4200.

-------
20Method OIA-1677, DW "Available Cyanide by Flow Injection, Ligand Exchange, and Amperometry," January 2004. EPA-
  821-R-04-001, Available from ALPKEM, A Division of Ol Analytical, P.O. Box 9010, College Station, TX 77842-9010.
21Sulfide levels below those detected using lead acetate paper may produce positive method interferences. Test samples
  using a more sensitive sulfide method to determine if a sulfide interference is present, and treat samples accordingly.
22Standard Methods Online, American Public Health Association, 800 I Street NW., Washington, DC 20001, available at
  http://www.standardmethods.org. The year in which each method was approved by the Standard Methods Committee
  is designated by the last two digits in the method number. The methods listed are the only online versions that may be
  used.
Excerpt from Table in  Appendix A to Subpart C of Part  141
Contaminant
Cyanide




Methodology
Manual Distillation
followed by
Spectrophotometric,
Amenable
Spectrophotometric
Manual
Selective Electrode
Headspace Gas
Chromatography/Mass
Spectrometry
EPA
method





SM
21st
edition1

4500-
CI\TG
4500-
CI\TE
4500-
CI\TF

SM
22nd
edition28

4500-
CI\TG
4500-
CI\TE
4500-
CI\TF

SM
online3





ASTM4
D2036-
06 A
D2036-
06 B
D2036-
06 A


Other




ME355.017
  Standard Methods for the Examination of Water and Wastewater, 21st edition (2005). Available from American Public
  Health Association, 800 I Street, NW., Washington, DC 20001-3710.
  Standard Methods Online are available at http://www.standardmethods.org. The year in which each method was
  approved by the Standard Methods Committee is designated by the last two digits in the method number. The
  methods listed are the only online versions that may be used.
  Available from ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959 or http://astm.org.
  The methods listed are the only alternative versions that may be used.
  Method ME355.01, Revision 1.0. "Determination of Cyanide in Drinking Water by GC/MS Headspace," May 26, 2009.
  Available at http://www.nemi.gov or from James Eaton, H & E Testing Laboratory, 221 State Street, Augusta, ME
  04333. (207) 287-2727.
 8Standard Methods for the Examination of Water and Wastewater, 22nd edition (2012). Available from American Public
  Health Association, 800 I Street NW., Washington, DC 20001-3710.

-------
Matching up the Methodologies in the cyanide entry in the Table at 40 CFR 141.23(a)(4)(i) with the
methods in the cyanide entries in the Tables at 40 CFR 141.23 (k)(l) & Appendix A to Subpart C of Part
141, the methods approved for free cyanides, total cyanides, and/or both can be determined.

Modified Methodologies and Methods for Total  and Free Cyanide Table
Contaminant




12. Cyanide





























Methodology




Manual Distillation
followed by

Spectrophotometric,
Amenable

Spectrophotometric
Manual

Spectrophotometric
Semi-automated

Selective Electrode


UV, Distillation,
Spectrophotometric


Micro Distillation, Flow
Injection,
Spectrophotometric

Ligand Exchange and
Amperometry


Headspace Gas
Chromatography/Mass
Spectrometry
EPA













335.4
(Rev.
1.0)


















ASTM




D2036-
98 A, -
06 A
D2036-
98 B,-
06 B
D2036-
98 A, -
06 A














D6888-
04





SM
(18th,
19th,
20th
ed.)
4500-
CATC

4500-
CN-G

4500-
CN~E




4500-
CI\TF
















SM
(21st,
22nd
ed.)




4500-
CN-G

4500-
CN~ E




4500-
CI\TF
















SM
Online






4500-
CN-G-
99
4500-
CN~ E-
99



4500-
CN-F-
99















Other










USGS 1-
3300-85







Kelada-01
(Rev. 1.2;
EPA821-B-
01-009)
QuikChem
10-204-00-
l-X(Rev.
2.1)
OIA-1677,
DW (EPA
821-R-04-
001)
ME355.01
(Rev. 1.0)

                           TOTAL
FREE
BOTH
Note: The Headspace GC/MS Method ME 355.01, Rev. 1.0 was approved through an expedited methods
approval action for the determination of free cyanide in Aug. 2009 (74 FR 38348).

-------
Separating the free and total methods results in the following modified Tables. Please note the following
for both Tables:
    1.  For the Cyanide methods referenced from Standard Methods, 4500-CN- Sections A. Introduction
       and B. Preliminary Treatment of Samples are included by reference.
    2.  SM 4500-CN- C in the unapproved editions allowed the use of magnesium chloride (MgCI2) to
       be optional, provided no supportive data in changing the chemistry, and thus were not
       approved.

Modified Table for Total  Cyanide
Methodology
Manual Distillation
followed by
Manual
Spectrophotometry
Manual Distillation
followed by Semi-
Automated
Spectrophotometry
Manual Distillation
followed by
Cyanide-Selective
Electrode
Automated UV
Distillation
followed by
Automated
Spectrophotometry
Micro Distillation,
Flow Injection,
followed by
Automated
Spectrophotometry
EPA

335.4
(Rev. 1.0)



ASTM
D2036-98 A, -06 A




SM (ed.)
4500-C/\TC(18th, 19th
& 20th)
+
4500-C/\TŁ(18th, 19th,
20th, 21st, 22nd, &-99
online)

4500-CATC(18th, 19th
& 20th)
+
4500-CN- F (18th, 19th,
20th, 21st, 22nd, &-99
online)


Other
USGS 1-3300-85


Kelada-01 (Rev.
1.2;EPA821-B-01-
009)
QuikChem 10-204-
00-1-X (Rev. 2.1)

-------
Modified Table for Free Cyanide
Methodology
Manual Distillation
followed by Manual
Spectrometry,
Cyanides Amenable to
Chlorination1 2
Manual Distillation
followed by Cyanide-
Selective Electrode2
Automated UV
Distillation followed by
Automated
Spectrophotometry3
Ligand Exchange and
Amperometry2
Headspace Gas
Chromatography/Mass
Spectrometry
EPA





ASTM
D2036-98 A, -06 A
+
D2036-98 B, -06 B


D6888-04

SM (ed.)
4500-CI\rG(18th, 19th,
20th, 21st, 22nd, &-99
online)
+
4500-CATC(18th, 19th
& 20th)
+
4500-CN- E (18th, 19th,
20th, 21st, 22nd, &-99
online)
4500-CN- F (18th, 19th,
20th, 21st, 22nd, &-99
online)



Other


Kelada-01 (Rev.
1.2;EPA821-B-01-
009)
OIA-1677, DW
(EPA 821-R-04-
001)
ME355.01 (Rev.
1.0)
1  To determine cyanides amenable to chlorination, distillation as described in Part C of the Standard Method is still
  required. This requires analysis of two sample aliquots. The first aliquot is subjected to a chlorine treatment to
  decompose the cyanides. The second aliquot has no chlorine treatment. Both aliquots are distilled followed by manual
  Spectrometry. The difference between the cyanide concentrations found in the two samples is expressed as cyanides
  amenable to chlorination.
2  Free cyanide omits the distillation, digestion or ligand exchange.
3  Measures "free" cyanides when UV-digestor is bypassed.
Clean versions of the modified Tables for Total and Free Cyanide are shown below.

-------
Modified Table for Total Cyanide (clean version]
Methodology
Manual Distillation
followed by Manual
Spectrophotometry
Manual Distillation
followed by Semi-
Automated
Spectrophotometry
Manual Distillation
followed by
Cyanide-Selective
Electrode
Automated UV
Distillation followed
by Automated
Spectrophotometry
Micro Distillation,
Flow Injection,
followed by
Automated
Spectrophotometry
EPA

335.4
(Rev.
1.0)



ASTM
D2036-98 A, -06 A




SM (ed.)
4500-CI\TC(18th, 19th &
20th)
+
4500-CN- E (18th, 19th,
20th, 21st, 22nd, &-99
online)

4500-CN- C (18th, 19th &
20th)
+
4500-CN- F (18th, 19th,
20th, 21st, 22nd, &-99
online)


Other
USGS 1-3300-85


Kelada-01 (Rev.
1.2;EPA821-B-
01-009)
QuikChem 10-
204-00-1-X (Rev.
2.1)

-------
Modified Table for Free Cyanide (clean version)
Methodology
Manual
Spectrometry,
Cyanides Amenable
to Chlorination1'2
Cyanide-Selective
Electrode2
Automated
Spectrophotometry3
Amperometry2
Headspace Gas
Chromatography/M
ass Spectrometry
EPA





ASTM
D2036-98 A, -06 A
D2036-98 B, -06 B


D6888-04

SM (ed.)
4500-CN- G (18th, 19th,
20th, 21st, 22nd, &-99
online)
4500-CN- C (18th, 19th &
20th)
4500-CN- E (18th, 19th,
20th, 21st, 22nd, &-99
online)
4500-CN- F (18th, 19th,
20th, 21st, 22nd, &-99
online)



Other


Kelada-01 (Rev.
1.2; EPA 821-B-
01-009)
OIA-1677, DW
(EPA821-R-04-
001)
ME355.01 (Rev.
1.0)
1 To determine cyanides amenable to chlorination distillation as described in Part C of the Standard Method is still
  required. This requires analysis of two sample aliquots. The first aliquot is subjected to a chlorine treatment to
  decompose the cyanides. The second aliquot has no chlorine treatment. Both aliquots are distilled followed by manual
  Spectrometry. The difference between the cyanide concentrations found in the two samples is expressed as cyanides
  amenable to chlorination.
2 Free cyanide omits the distillation, digestion or ligand exchange.
3 Measures "free" cyanides when UV-digestor is bypassed.
                                                    10

-------