[Federal Register Volume 63, Number 129 (Tuesday, July 7, 1998)]
[Proposed Rules]
[Pages 36810-36824]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-17963]
[[Page 36809]]
_______________________________________________________________________
Part IV
Environmental Protection Agency
_______________________________________________________________________
40 CFR Part 136
Guidelines Establishing Test Procedures for the Analysis of Pollutants;
Available Cyanide; Proposed Rule
Federal Register / Vol. 63, No. 129 / Tuesday, July 7, 1998 /
Proposed Rules
[[Page 36810]]
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 136
[FRL-6121-5]
RIN 2040-AC76
Guidelines Establishing Test Procedures for the Analysis of
Pollutants; Available Cyanide
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: This proposed regulation would amend the Guidelines
Establishing Test Procedures for the Analysis of Pollutants under
Section 304(h) of the Clean Water Act by adding Method OIA-1677:
Available Cyanide by Flow Injection, Ligand Exchange, and Amperometry.
Method OIA-1677 employs flow injection analysis (FIA) to measure
``available cyanide.'' Method OIA-1677 is being proposed as an
additional test procedure for measuring the same cyanide species as are
measured by currently approved methods for cyanide amenable to
chlorination (CATC). In some matrices, CATC methods are subject to
significant test interferences. In contrast, Method OIA-1677
demonstrates greater specificity for cyanide for matrices in which
interferences have been encountered using CATC methods. In addition,
Method OIA-1677 measures cyanide at lower concentrations and offers
improved precision and accuracy over currently approved CATC methods.
Method OIA-1677 also offers improved laboratory safety and reduces
laboratory waste compared to currently approved CATC methods. This
significantly reduces the generation of hazardous waste by the
laboratory. Cyanide analysis by Method OIA-1677 is also more rapid than
by currently approved methods.
DATES: Comments on this proposal must be submitted on or before
September 8, 1998.
ADDRESSES: Send written comments on the proposed rule to ``Method OIA-
1677'' Comment Clerk (Docket #W-98-08); Water Docket (4101);
Environmental Protection Agency; 401 M Street, SW., Washington, DC
20460. Commenters are requested to submit any references cited in their
comments. Commenters are also requested to submit an original and 3
copies of their written comments and enclosures. Commenters that want
receipt of their comments acknowledged should include a self addressed,
stamped envelope. All comments must be postmarked or delivered by hand.
No facsimiles (faxes) will be accepted.
Data available: A copy of the supporting documents cited in this
proposal is available for review at EPA's Water Docket; 401 M Street,
SW, East Tower Basement, Washington, DC 20460. For access to docket
materials, call (202) 260-3027 between 9 a.m. and 3:30 p.m. for an
appointment. An electronic version of Method OIA-1677 will be available
via the Internet at http://www.epa.gov/OST/Tools.
FOR FURTHER INFORMATION CONTACT: Dr. Maria Gomez-Taylor, Engineering
and Analysis Division (4303), USEPA Office of Science and Technology,
401 M Street, SW, Washington, DC 20460, or call (202) 260-1639.
SUPPLEMENTARY INFORMATION:
Potentially Affected Entities
EPA Regions, as well as States, Territories and Tribes authorized
to implement the National Pollutant Discharge Elimination System
(NPDES) program, issue permits that comply with the technology-based
and water quality-based requirements of the Clean Water Act. In doing
so, the NPDES permitting authority, including authorized States,
Territories, and Tribes, make a number of discretionary choices
associated with permit writing, including the selection of pollutants
to be measured and, in many cases, limited in permits. If EPA has
``approved'' standardized testing procedures (i.e., promulgated through
rulemaking) for a given pollutant, the NPDES permit must include one of
the approved testing procedures or an approved alternate test
procedure. Therefore, entities with NPDES permits could be affected by
the standardization of testing procedures in this rulemaking. These
entities may be affected because NPDES permits may incorporate one of
the standardized testing procedures in today's rulemaking. In addition,
when a State, Territory, or authorized Tribe provides certification of
federal licenses under Clean Water Act section 401, States, Territories
and Tribes are directed to use the standardized testing procedures.
Categories and entities that may ultimately be affected include:
------------------------------------------------------------------------
Examples of potentially
Category affected entities
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State and Territorial Governments and States, Territories, and Tribes
Indian Tribes. authorized to administer the
NPDES permitting program;
States, Territories, and
Tribes providing certification
under Clean Water Act section
401; Governmental NPDES
permittees.
Industry............................... Industrial NPDES permittees.
Municipalities......................... Publicly-owned treatment works
with NPDES permits.
------------------------------------------------------------------------
This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be affected by this
action. This table lists the types of entities that EPA is now aware
could potentially be affected by this action. Other types of entities
not listed in the table could also be affected. If you have questions
regarding the applicability of this action to a particular entity,
consult the person listed in the preceding FOR FURTHER INFORMATION
CONTACT section.
I. Authority
Today's proposal is pursuant to the authority of sections 301,
304(h), and 501(a) of the Clean Water Act (CWA), 33 U.S.C. 1314(h),
1361(a) (the ``Act''). Section 301 of the Act prohibits the discharge
of any pollutant into navigable waters unless the discharge complies
with a National Pollutant Discharge Elimination System (NPDES) permit,
issued under section 402 of the Act. Section 304(h) of the Act requires
the Administrator of the EPA to ``promulgate guidelines establishing
test procedures for the analysis of pollutants that shall include the
factors which must be provided in any certification pursuant to section
401 of this Act or permit applications pursuant to section 402 of this
Act.'' Section 501(a) of the Act authorizes the Administrator to
``prescribe such regulations as are necessary to carry out his function
under this Act.'' The Administrator also has made these test procedures
applicable to monitoring and reporting of NPDES permits (40 CFR part
122, Sec. 122.21, 122.41, 122.44, and 123.25), and implementation of
the pretreatment standards issued under section 307 of the Act (40 CFR
part 403, Secs. 403.10 and 402.12).
[[Page 36811]]
II. Background
A. Cyanide
Cyanides are, as a class, one of the toxic pollutants pursuant to
section 307(a)(1) of CWA (see the list of toxic pollutants at 40 CFR
401.15). Total cyanide is a priority pollutant as derived from the
toxic pollutant list (see 40 CFR Part 423, Appendix A).
In the context of analytical methods, cyanide or cyanides refers to
the group of simple and complex chemical compounds that can be
determined as cyanide ion (CN-). Cyanides are of the form
A(CN)X, where A is an alkali such as sodium or potassium, or
a metal such as calcium, and x is the number of CN groups attached to
A. Cyanides are present in aqueous solutions as CN- and as
hydrocyanic acid (HCN or hydrogen cyanide). The proportion of
CN- and HCN in solution is dependent on the pH and the
dissociation constant for HCN. At low pH, the cyanide exits as HCN; at
high pH, it exists as CN-. At the near-neutral or slightly
acidic pH of most natural waters, nearly all cyanide is present as HCN.
Most of the metal cyanides are insoluble or only slightly soluble in
water but may form a variety of soluble cyanide complexes when a
cyanide such as potassium or sodium cyanide is present.
Hydrogen cyanide is the cyanide species most toxic to aquatic life.
The toxicity of the other cyanides is attributable to the degree of
their dissociation and conversion to HCN. Some cyano-metal complexes,
such as those of zinc and cadmium, dissociate almost totally (i.e., a
knowledge of the complex can be used to determine the amount of
cyanide). Other cyano-metal complexes, such as those of iron,
dissociate little. For these complexes, a large amount can be present
without cyanide being detected. Still, other complexes, such as
mercury, nickel, and silver, dissociate partially and only under
certain conditions. For complexes that release some, but not all, of
the cyanide ion, the amount of dissociation must be known to determine
the amount of cyanide. This total, partial, or near lack of
dissociation presents a difficulty in the determination of cyanides, as
explained below.
B. Need for Improved Methods for Cyanide
Methods proposed in Guidelines Establishing Test Procedures for the
Analysis of Pollutants under section 304(h) of the Clean Water Act are
listed at Title 40 of the Code of Federal Regulations, Sec. 136.3. EPA
had received numerous letters and comments regarding interference
problems when the currently approved methods were used to test certain
sample matrices and was therefore aware of the need for a cyanide
method that reduced or eliminated these interferences. A method for
measuring available cyanide by flow injection analysis (FIA) had been
developed by ALPKEM in cooperation with the University of Nevada at
Reno, Mackay School of Mines in 1995. Besides overcoming most matrix
effect problems, Method OIA-1677 uses amperometry as an innovative
technology to improve the detection of available cyanide. Method OIA-
1677 is faster, more accurate and precise, and allows determination of
available cyanide at lower concentrations than currently approved
methods. Method OIA-1677 is also safer because it requires a smaller
amount of a potentially hazardous sample, requires less manual
operations where accidents could lead to exposure, and uses less
hazardous substances in the sample preparation and determinative steps.
C. Methods for Determination of Cyanide
Methods presently approved at 40 CFR Part 136 measure cyanide in
two ways: as ``total cyanide'' and ``cyanide amenable to chlorination''
(CATC). A third way is as ``weak-acid dissociable'' (WAD) cyanide but
there is presently no approved method for WAD cyanide in 40 CFR Part
136. Methods for determination of total cyanide attempt to measure all
cyanide species that may dissociate in the environment over time and
when exposed to natural forces (e.g., heat, light, water of varying
hardness, pH) but ultimately fail to do so because many species cannot
be dissociated completely under normal laboratory conditions. The CATC
and WAD methods, and Method OIA-1677, which employs ligand exchange,
all attempt to measure ``available'' cyanide, i.e., cyanide species
that dissociate in the presence of chlorine and/or acid. The species of
cyanide measured by these methods are cyanide ion (CN-),
hydrogen cyanide (HCN), and the cyano-complexes of zinc, copper,
cadmium, mercury, nickel, and silver. The net result is that the WAD,
CATC, and OIA-1677 methods all measure nearly the same species of
cyanide. The term ``available cyanide'' is used in Method OIA-1677
because the chlorination reaction used in the CATC methods is not
employed, although the cyanides determined are the same.
Methods for total cyanide employ reflux distillation in the
presence of sulfuric acid and magnesium chloride to dissociate
CN- from cyanide-metal complexes. This process is more
vigorous than the dissociation processes used in the WAD, CATC, and
ligand-exchange methods, and a greater number of cyanide species are
dissociated in the distillation process. The HCN liberated during the
distillation is captured in an aqueous solution of sodium hydroxide and
the cyanide in the solution is determined spectrophotometrically or
titrimetrically.
Cyanide amenable to chlorination (CATC) is determined by
chlorinating the available cyanide in the sample using calcium
hypochlorite (Ca(OCl)2), measuring the HCN using the total
procedure, and finding the CATC concentration by difference between the
total cyanide measured before and after the chlorination.
Available cyanide is determined in Method OIA-1677 by flow
injection, ligand exchange, and amperometric detection. The ligand-
exchange reagents displace cyanide from cyano-metal complexes. Further
details of Method OIA-1677 are given in a description of the method
below.
As stated above, no method measures all species of cyanides because
several species (such as cobalt and gold cyanides) are so stable that
they are either not dissociated or are only slightly dissociated in the
reflux distillation or chlorination processes. Method OIA-1677 and CATC
methods measure easily dissociable and partially dissociable species.
Most notable among the partially dissociable species are the certain
cyanides of nickel, mercury, and silver when these cyanides are present
at high concentrations (ca 2 mg/L). These cyanides are recovered in the
range of 55--85 percent in the CATC methods. In contrast, these species
are recovered completely in Method OIA-1677, and this is the
significant difference between the performance of Method OIA-1677 and
approved methods for CATC. As a result, if a sample contains high
concentrations of certain cyanides of nickel, mercury, or silver, the
result will be somewhat higher when Method OIA-1677 is used, provided
no interferences are present. At concentrations below approximately 0.2
mg/L, the recoveries of these cyanides from CATC methods and Method
OIA-1677 are all approximately equivalent and near 100 percent.
D. Effect of Interferences on Cyanide Methods
The CATC determination is highly susceptible to interferences, as
many substances other than cyanides can react in the chlorination
process. For an overview of the nature and magnitude of these
interferences, see the paper
[[Page 36812]]
presented by Goldberg, et. al. at the Seventeenth Annual EPA Conference
on Analysis of Pollutants in the Environment, May 3-5, 1994 (available
from the EPA Sample Control Center, 300 N. Lee Street, Alexandria, VA
22314 (703-519-1140). Interferences in the CATC determination may be by
thiocyanate (SCN-), sulfide (S2-), carbonates
(HCO3-, CO32-), nitrite
(NO2-), oxidants (ClO4-,
O3, H2O2), bisulfite
(HSO3-), formaldehyde (HCHO), surfactants, and
metals. Method OIA-1677 is either not susceptible to these
interferences or contains procedures that eliminate these interferences
or mitigate their effects. The reason that this method is much less
susceptible to interferences than the approved CATC methods is that the
chlorination reaction is not employed. Rather, the aqueous sample
passes a gas diffusion membrane through which the HCN diffuses, as
explained in greater detail in the later section of this preamble that
describes Method OIA-1677. With approval of Method OIA-1677, EPA
believes that most of the reported interference problems in the
determination of cyanide would be overcome.
Interferences in the CATC methods normally produce an inflated
result for cyanide and, in many instances, the measured level exceeds
the concentration for total cyanide, potentially providing a more
controversial result in some regulatory contexts. Because Method OIA-
1677 is nearly immune to the interferences that inflate results from
CATC methods, the result of an analysis using Method OIA-1677 will
nearly always be lower, and therefore closer to the true value for
cyanide than a result from an analysis using a CATC method. The only
exception may be for an analysis in which interferences are not present
but certain cyanides of nickel, mercury, or silver are present at high
concentrations, as described above. Therefore, the tradeoff in use of
Method OIA-1677 versus presently approved CATC methods is that, with
Method OIA-1677, there is a reduced susceptibility to interferences,
whereas with approved CATC methods, there is a somewhat decreased
result if certain cyanides of nickel, mercury, or silver are present at
high concentrations. EPA believes that the tradeoff heavily favors use
of Method OIA-1677 based on the expected susceptibility of CATC methods
to interferences combined with the small probability that a cyanide of
nickel, mercury, and silver will be present at a high concentration and
be the dominant cyanide in a given discharge. Dominance is important
because if a cyanide of nickel, mercury, or silver is present at a
concentration that is small in comparison to another cyanide present,
the effect on the measured cyanide concentration will be diminished in
proportion to the concentration relative to the other cyanide.
Because the lowest result for a given cyanide determination can be
produced by either Method OIA-1677 or by a presently approved CATC
method, dischargers will likely choose the method that produces the
lowest result. The adverse environmental impact to choosing presently
approved CATC methods is that not all of the nickel, mercury, or silver
cyanide will be recovered (and measured), if any of these cyanides are
present.
E. Regulatory Effects of Use of Different Methods
A regulatory problem may occur when a sample of a given discharge
is split and a discharger chooses Method OIA-1677 and a regulatory
authority chooses an approved CATC method (or vice versa) and one
result shows a violation of a permit limit and the other does not. EPA
believes that the difference can be worked out in technical discussions
between the discharger and the regulatory authority based on the data
produced. If these data show that an interference was present, Method
OIA-1677 will likely produce the lower result and this result should be
relied upon. On the other hand, if the discharger knows that nickel,
mercury or silver cyanide is present in the discharge in high
concentration and is dominant, the result from the CATC method would be
appropriate because it is most consistent with the method used for
permit development. Further, it is unlikely that a discharger would
select Method OIA-1677 if it knew that a cyanide of nickel, mercury, or
silver was present at high concentration, unless interferences were so
large that they overwhelmed the effect of the greater recovery. The
concern would then be that the regulatory authority employed Method
OIA-1677, not knowing that a cyanide of nickel, mercury, or silver was
present at a high concentration and dominant in the discharge. However,
the discharger could inform the regulatory authority of this presence
and may rely upon the text in this preamble and in the technical
literature to convince the regulatory authority that the violation is a
result of the regulatory authority's use of Method OIA-1677. Finally,
EPA believes that occurrences of this problem will be rare and it is
more likely that use of Method OIA-1677 will produce a lower result
because it is nearly interference free.
F. Analysis Time
The reflux distillation procedure required by CATC methods,
including setup and measurement, takes approximately two hours to
perform. Therefore, determination of CATC takes approximately four
hours of analysis time. In contrast, Method OIA-1677 takes
approximately two minutes to perform. This difference will be
especially significant for laboratories performing many CATC analyses.
III. Summary of Proposed Rule
A. Introduction
This proposed rule would make available at part 136 an additional
test procedure for measurement of available cyanide. Currently approved
methods for measurement of available cyanide are based on sample
chlorination. Method OIA-1677 as proposed today uses a flow injection/
ligand exchange technique to measure available cyanide. Although Method
OIA-1677 and chlorination methods both measure available cyanide, it is
possible that the results produced by the two techniques will vary
slightly, as detailed above. EPA offers Method OIA-1677 as another
testing procedure for a variety of purposes including: permit
applications and compliance monitoring under the National Pollutant
Discharge Elimination System (NPDES) under CWA Section 402; ambient
water quality monitoring; CWA Section 401 certifications; development
of new effluent limitations guidelines, pretreatment standards, and new
source performance standards in EPA's water programs; and for general
laboratory use. This rulemaking does not propose to repeal any of the
currently approved methods that test for available cyanide. For NPDES
permits, the permitting authority should decide which method is
appropriate for the specific NPDES permit based on the circumstances of
the particular effluent measured. If the permitting authority does not
specify the method to be used for the determination of available
cyanide, a discharger would be able to use Method OIA-1677 or any of
the presently approved CATC methods.
B. Summary of Proposed Method OIA-1677
Method OIA-1677 is divided into two parts: sample pretreatment and
cyanide quantification via amperometric detection. In the sample
pretreatment step, ligand-exchange reagents are
[[Page 36813]]
added to a 100-mL sample. The ligand-exchange reagents displace cyanide
ions (CN-) from weak and intermediate strength metallo-
cyanide complexes.
In the flow-injection analysis system, a 200-L aliquot of
the pretreated sample is injected into the flow injection manifold. The
addition of hydrochloric acid converts cyanide ion to hydrogen cyanide
(HCN). The hydrogen cyanide diffuses through a membrane into an
alkaline receiving solution where it is converted back to cyanide ion
(CN-). The amount of cyanide ion in the alkaline receiving
solution is measured amperometrically with a silver working electrode,
silver/silver chloride reference electrode, and platinum counter
electrode at an applied potential of zero volt. The current generated
in the cell is proportional to the concentration of cyanide in the
original sample, as determined by calibration.
C. Comparison of Method OIA-1677 to Current Methods
Methods currently approved for determination of available cyanide
all test for CATC. Although they represent the best methods available
to date, these methods are prone to matrix interference problems. EPA
considers Method OIA-1677 to be a significant addition to the suite of
analytical testing procedures for available cyanide because it (1) has
greater specificity for cyanide in matrices where interferences have
been encountered using currently approved methods, (2) has improved
precision and accuracy compared to currently approved CATC cyanide
methods, (3) measures available cyanide at lower concentrations, (4)
offers improved analyst safety, (5) shortens sample analysis time, and
(6) reduces laboratory waste.
Method OIA-1677 is not subject to interferences from organic
species. The flow-injection technique of Method OIA-1677 excludes all
interferences, except sulfide. Sulfide is eliminated by treating the
sample with lead carbonate and removing the insoluble lead sulfide by
filtration prior to introduction of the sample to the amperometric cell
used for cyanide detection.
Method OIA-1677 was tested against two existing cyanide methods:
Method 335.1, an EPA-approved CATC method, and Standard Method (SM)
4500 CN- I, a weak-acid dissociable (WAD) cyanide method.
Comparative recovery and precision data were generated from simple
metallo-cyanide species in reagent water. Recovery and precision of
each method was comparable for the easily dissociable cyanide species.
Method OIA-1677 showed superior precision and recoveries of mercury
cyanide complexes.
While Method 335.1 does not specify a method detection limit,
colorimetric detection is ``sensitive'' to approximately 5 g/
L. The method detection limit (MDL; described at 40 CFR part 136,
Appendix B) is 0.5 g/L for Method OIA-1677, as determined in a
multi-laboratory study.
Method OIA-1677 offers improved analyst safety for two reasons. The
first reason centers on the generation of hydrogen cyanide gas, a
highly toxic compound. Although the proposed flow-injection analysis
(FIA) method and currently approved CATC methods all generate HCN, the
currently approved methods generate a larger quantity of gas during
distillation in an open distillation system. As such, extra care must
be taken to prevent accidental release of HCN into the laboratory
atmosphere. Method OIA-1677, because it tests a much smaller sample,
generates significantly less HCN. In addition, the gas is contained in
a closed system with little possibility for release. The second reason
for improved safety centers on the use of hazardous substances.
Currently approved CATC methods require use of hazardous substances in
the distillation and color developing processes. These hazardous
substances include hydrochloric acid, pyridine, barbituric acid,
chloramine-T, and pyrazolone. Method OIA-1677 requires only
hydrochloric acid at a much lower concentration than is used in CATC
procedures.
Method OIA-1677 offers a reduced analysis time which should
increase sample throughput in the laboratory. Method OIA-1677 uses an
automated mixing of the sample with hydrochloric acid and exposure to
the gas diffusion membrane in order for the sample concentration to be
determined. This process takes approximately two minutes per sample. As
a comparison, Method 335.1 requires a one-hour distillation procedure
plus the time necessary to add and develop the sample color to
determine the presence of cyanide.
Less laboratory waste is generated in Method 1667 because it
requires a much smaller sample size for testing. Method 335.1 requires
handling a sample size of 500 mL for distillation. Method OIA-1677
requires the addition of the ligand exchange reagents to 100 mL of
sample, from which 40-250 L is used for analysis. This reduces
the amount of both hazardous sample and toxic reagents that must be
handled and subsequently disposed.
D. Quality Control
The quality control (QC) in Method OIA-1677 is more extensive than
the QC in currently approved methods for CATC. Method OIA-1677 contains
all of the standardized QC tests proposed in EPA's streamlining
initiative (62 FR 14976) and used in the 40 CFR part 136, Appendix A
methods. An initial demonstration of laboratory capability is required
and consists of: (1) An MDL study to demonstrate that the laboratory is
able to achieve the MDL and minimum level of quantification (ML)
specified in Method OIA-1677; and (2) an initial precision and recovery
(IPR) test, consisting of the analysis of four reagent water samples
spiked with the reference standard, to demonstrate the laboratory's
ability to generate acceptable precision and recovery. An important
component of these and other QC tests required in Method OIA-1677 is
the use of mercuric cyanide (Hg(CN)2) as the reference
standard for spiking. Mercuric cyanide was chosen because it is fully
recovered in Method OIA-1677 and weak-acid dissociable (WAD) methods,
whereas mercuric cyanide is only partially recovered in the CATC
method. Therefore, mercuric cyanide demonstrates the ability of the
ligand-exchange reagents to liberate cyanide from moderately strong
metal-cyano complexes. Method OIA-1677 requires the use of standards of
known composition and purity, which facilitates more accurate
determination of recovery and precision and minimizes variability that
may be introduced from spiking substances of unknown or indeterminate
purity.
Ongoing QC consists of the following tests that would need to
accompany each analytical batch, i.e., a set of 10 samples or less
pretreated at the same time:
Verification of calibration of the flow injection
analysis/amperometric detection system, to verify that instrument
response has not deviated significantly from that obtained during
calibration.
Analysis of a matrix spike (MS) and matrix spike duplicate
(MSD) to demonstrate method accuracy and precision and to monitor
matrix interferences. Hg(CN)2 is the reference standard used
for spiking.
Analysis of a laboratory blank to demonstrate freedom from
contamination.
Analysis of a laboratory control sample to demonstrate
that the method remains under control.
Method OIA-1677 contains QC acceptance criteria for all QC tests.
Compliance with these criteria allows a
[[Page 36814]]
data user to evaluate the quality of the results. This increases the
reliability of results and provides a means for laboratories and data
users to monitor analytical performance, thereby providing a basis for
sound, defensible data.
E. Performance-based Measurement System
On October 6, 1997, EPA published a Notice of the Agency's intent
to implement a Performance Based Measurement System (PBMS) in all of
its programs to the extent feasible (62 FR 52098). The Agency is
currently determining the specific steps necessary to implement PBMS in
its programs and preparing an implementation plan. Final decisions have
not yet been made concerning the implementation of PBMS in water
programs. However, EPA is currently evaluating what relevant
performance characteristics should be specified for monitoring methods
used in the water programs under a PBMS approach to ensure adequate
data quality. EPA would then specify performance requirements in its
regulations to ensure that any method used for determination of a
regulated analyte is at least equivalent to the performance achieved by
other currently approved methods. Our expectation is that EPA will
publish its PBMS implementation strategy for water programs in the
Federal Register by the end of calendar year 1998.
Under PBMS, the analyst would have flexibility to modify Method
OIA-1677 or to use another method for the determination of available
cyanide provided the analyst demonstrates that the performance achieved
is at least equivalent to the approved method(s). Since inter-
laboratory performance data exists for Method OIA-1677, EPA is
proposing that these data be used to specify what performance
characteristics would be required for measurement of available cyanide
under PBMS. EPA is considering the following performance requirements
for the use of modified or alternative methods for the measurement of
available cyanide: (1) it measures the same cyanide species; (2) it
achieves an MDL that is equal or less than the MDL in Method OIA-1677,
or one-third the regulatory compliance level, whichever is greater; and
(3) it meets all the performance criteria specified in Table 1 of
Method OIA-1677 (initial precision and recovery, on-going precision and
recovery, calibration verification, and matrix spike/matrix spike
duplicate). The process for demonstrating acceptable performance is
specified in Section 9 of the method.
Once EPA has made its final determinations regarding implementation
of PBMS in programs under the Clean Water Act, EPA would incorporate
specific provisions of PBMS into its regulations, which may include
specification of the performance characteristics for measurement of
available cyanide and for other regulated pollutants in the water
program regulations.
EPA requests public comments on whether the performance
characteristics identified above (see Method OIA-1677 for performance
criteria) would be relevant performance characteristics under PBMS, and
whether there are other performance requirements that the Agency should
consider under PBMS for the measurement of available cyanide.
IV. Validation of the Method OIA-1677
ALPKEM developed the version of Method OIA-1677 proposed today
according to procedures set forth in EPA's Guide to Method Flexibility
and Approval of EPA Water Methods (EPA-821-D-96-004, December 1996)
which is available from the EPA's Water Resource Center (phone: 202-
260-7786). The version of Method OIA-1677 proposed today responds to
comments from users of earlier versions, results of the intra- and
interlaboratory studies, as well as results from several single-
laboratory MDL studies.
A. Intralaboratory Validation Study Results
Prior to interlaboratory testing, ALPKEM conducted a single-
laboratory validation study both to refine the method and to
demonstrate the method's specificity and selectivity. Those study
results, described briefly here, are detailed in the Report of the
Draft Method OIA-1677 Single Laboratory Validation Study that is
included in the docket for this proposed rule.
The single-laboratory study consisted of three sets of tests to
establish (1) the ability of Method OIA-1677 to identify the various
species of ``free'' metallo-cyanide complexes, (2) the ability of
Method OIA-1677 to identify cyanide in the presence of interferences,
and (3) the recovery and precision of Method OIA-1677 compared to EPA
Method 335.1 and SM 4500 CN-I. To determine Method OIA-1677's
identification of ``free'' metallo-cyanide complexes, two different
concentrations of 11 different metallo-cyanide complexes were each
analyzed individually in triplicate, for a total of 66 analyses. Method
OIA-1677 yielded recoveries ranging from 97 to 104 percent for six of
the eleven complexes (cadmium, copper, mercury, nickel, silver, and
zinc). However, as with the currently approved methods for available
cyanide, Method OIA-1677 did not determine cyanide in iron, gold, and
cobalt cyanide complexes.
To test the ability of Method OIA-1677's to identify cyanide in the
presence of other species, two different concentrations of 11
interferents were analyzed in triplicate for a single cyanide test
solution, resulting in a second set of 66 analyses. Even in the
presence of these interferents, cyanide recoveries ranged from 99 to
103 percent.
To compare the performance of Method OIA-1677 to the performance of
approved methods, 2 different concentrations of the same 11 ``free''
metallo-cyanide complexes given above were analyzed individually in
triplicate by the EPA-approved CATC Method 335.1, SM 4500 CN-I, and
Method OIA-1677. This resulted in a third set of 66 data points. These
results show improved recoveries and reduced relative standard
deviations for Method OIA-1677 compared to both the SM 4500 CN-I and
the CATC methods for selected analytes. For the mercury cyanide
complexes, recovery improved from 59 percent for SM 4500 CN-I to 99
percent for Method OIA-1677. High levels of interferences in the nickel
and silver determinations showed similar improvements over the CATC
method. However, data for zinc, cadmium, copper were comparable among
the three cyanide procedures. There was no recovery and thus no method
improvement for cobalt, gold, or iron cyanide complexes.
B. Interlaboratory Validation Study Results
In association with the Analytical Methods Staff (AMS) in EPA's
Office of Water, ALPKEM conducted an interlaboratory validation study.
Those study results, briefly described here, are detailed in a report
titled, The Interlaboratory Validation of Method OIA-1677, and are
included in the docket for this proposed rule.
The purpose of the interlaboratory study was (1) to confirm the
performance of Method OIA-1677 in multiple laboratories, (2) to assess
Method OIA-1677 interlaboratory data variability, and (3) to develop
Method OIA-1677 QC acceptance criteria.
Nine laboratories participated in the interlaboratory method
validation study, working cooperatively as the WAD Cyanide Round Robin
Group. Each laboratory analyzed an identical set of nine field samples
using Method OIA-1677. These field samples were
[[Page 36815]]
collected from nine different effluents ranging from a publicly owned
treatment works (POTW) to an industry likely to contain cyanide in its
effluent. Each sample was analyzed in triplicate using the FIA
procedure for a total of 243 analyses (9 laboratories x 9 samples in
triplicate).
Along with the analysis of the field samples, each laboratory
performed all required QC analyses, including initial calibration,
calibration verification, determination of initial precision and
recovery, blank analysis, determination of ongoing precision and
recovery (OPR), determination of matrix spike recovery and matrix spike
duplicate recovery (MS/MSD) in each sample type, assessment of recovery
of cyanide as Hg(CN)2 spiked into samples (ligand-exchange
reagent performance check or LERPC). In addition, each laboratory
performed an MDL study.
The relative standard deviation (RSD) of results across all
laboratories and all samples was 12 percent. The mean sample recoveries
across all effluent types tested was 96 percent, and the MS and MSD
mean recoveries were 99 percent across all effluent types tested. These
results exceed generally accepted norms for analytical chemistry
results.
Prior to collection of interlaboratory data, one study participant
submitted comments that focused on the difficulty in addition of the
proper amounts of WAD A & WAD B ligand-exchange reagents to a sample.
The difficulty occurred because of the variability of drop size. The
method was modified to designate a specific volume of ligand-exchange
reagent rather than a certain number of drops. The modified method was
distributed to interlaboratory study participants prior to testing.
C. Development of Quality Control Acceptance Criteria
Data from the interlaboratory study were used to develop QC
acceptance criteria for Method OIA-1677. Laboratory procedures and QC
calculations are fully described in the interlaboratory study report.
Criteria were developed for initial precision and recovery (IPR),
ongoing precision and recovery (OPR), and recovery of cyanide as
Hg(CN)2 spiked into reagent water samples (ligand-exchange
reagent performance check, LERPC). QC acceptance criteria for the IPR,
OPR, matrix spike (MS), matrix spike duplicate (MSD), and relative
percent difference (RPD) for the MS and MSD were calculated using
procedures described in EPA's Streamlining Guide. In addition to those
procedures, QC acceptance criteria also were developed for
Hg(CN)2 at the upper level of the analytical range. Criteria
for this LERPC test were developed according to the same procedure as
for the IPR test.
D. Method Detection Limit Studies
Nine single-laboratory MDL studies were performed as part of the
effort to determine MDLs and minimum levels (MLs). The MDL is defined
as the minimum concentration of a substance that can be measured and
reported with 99 percent confidence that the analyte concentration is
greater than zero. To determine the MDL, the laboratories were required
to follow the procedure in Appendix B to 40 CFR part 136.
In the Appendix B procedure, seven aliquots of reagent water are
spiked with the analyte or analytes of interest and analyzed by the
proposed method. For the MDL studies, KCN was used as the spiking
material. Spike levels were in the range of one to five times the
estimated detection limit. Following addition of KCN, cyanide levels in
each of the seven aliquots was determined. The MDL was determined to be
0.5 g/L CN-.
The minimum level of quantitation (ML) is defined as the level at
which the entire analytical system produces a recognizable signal and
an acceptable calibration point. The ML is determined by multiplying
the MDL by 3.18 and rounding the resulting value to the number nearest
to (1, 2, or 5) x 10n, where n is an integer. The ML for
Method OIA-1677 was calculated to be 1.0 g/L CN-.
However, because this calculated value was below the lowest calibration
standard used in the MDL study, the ML was set at the level of that
standard, 2.0 g/L CN-. Results of the MDL studies,
along with the relevant calculations, are detailed in the
interlaboratory study report.
V. Status of Currently Approved Methods
This action proposes to make Method OIA-1677 available for
measurement of available cyanide. The previously approved methods for
analysis of available cyanide, EPA Method 335.1, SM 4500-CN G, and ASTM
D2036-91(B), would not be withdrawn or otherwise affected by this
regulation. EPA specifically invites comment on this aspect of the
proposal, including the possible consequences and solutions if EPA were
to withdraw any such methods.
VI. Regulatory Requirements
A. Executive Order 12866
Under Executive Order 12866, (58 FR 51735 (October 4, 1993)) the
Agency must determine whether a regulatory action is ``significant''
and therefore subject to OMB review and the requirements of the
Executive Order. The Order defines ``significant regulatory action'' as
one that is likely to result in a rule that may: (1) have an annual
effect on the economy of $100 million or more or adversely affect in a
material way the economy, a sector of the economy, productivity,
competition, jobs, the environment, public health or safety, or State,
local, or tribal governments or communities; (2) create a serious
inconsistency or otherwise interfere with an action taken or planned by
another agency; (3) materially alter the budgetary impact of
entitlements, grants, user fees, or loan programs or the rights and
obligations of recipients thereof; or (4) raise novel legal or policy
issues arising out of legal mandates, the President's priorities, or
the principles set forth in the Executive Order.''
This regulation is not significant because it approves a testing
procedure for use in compliance monitoring and data gathering but does
not require its use. It has been determined that this rule is not a
``significant regulatory action'' under the terms of Executive Order
12866 and is therefore not subject to OMB review.
B. Unfunded Mandates Reform Act
Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), P.L.
104-4, establishes requirements for Federal agencies to assess the
effects of their regulatory actions on State, local, and tribal
governments and the private sector. Under section 202 of the UMRA, EPA
generally must prepare a written statement, including a cost-benefit
analysis, for proposed and final rules with ``Federal mandates'' that
may result in expenditures to State, local, and tribal governments, in
the aggregate, or to the private sector, of $100 million or more in any
one year. Before promulgating an EPA rule for which a written statement
is needed, section 205 of the UMRA generally requires EPA to identify
and consider a reasonable number of regulatory alternatives and adopt
the least costly, most cost-effective or least burdensome alternative
that achieves the objectives of the rule. The provisions of section 205
do not apply when they are inconsistent with applicable law. Moreover,
section 205 allows EPA to adopt an alternative other than the least
costly, most cost-effective or least burdensome alternative if the
Administrator publishes with the final rule an explanation why that
alternative was not adopted. Before EPA establishes any regulatory
requirements that may significantly or uniquely affect small
[[Page 36816]]
governments, including tribal governments, it must have developed under
section 203 of the UMRA a small government agency plan. The plan must
provide for notifying potentially affected small governments, enabling
officials of affected small governments to have meaningful and timely
input in the development of EPA regulatory proposals with significant
Federal intergovernmental mandates, and informing, educating, and
advising small governments on compliance with the regulatory
requirements.
Today's proposed rule contains no Federal mandates (under the
regulatory provisions of title II of the UMRA) for State, local, or
Tribal governments or the private sector. The proposed rule would
impose no enforceable duty on any State, local or Tribal governments or
the private sector. This rule proposes alternative analytical tests
procedures which merely standardize the procedures when testing is
otherwise required by a regulatory agency. Therefore, the proposed rule
is not subject to the requirements of sections 202 and 205 of the UMRA.
EPA invites comment on its conclusions regarding whether alternate test
procedures constitute a federal mandate.
EPA has determined that this proposed rule contains no regulatory
requirements that might significantly or uniquely affect small
governments and thus this proposed rule is not subject to the
requirements of section 203 of UMRA. This proposed rule would simply
approve an additional test procedure for measurements that may be
required under the CWA.
C. Regulatory Flexibility Act
Pursuant to section 605(b) of the Regulatory Flexibility Act, 5
U.S.C. 605(b), the Administrator certifies that this rule will not have
a significant economic impact on a substantial number of small
entities. This regulation simply approves an additional testing
procedure for the measurement of available cyanide which may be
required in the implementation of the CWA.
D. Paperwork Reduction Act
In accordance with the Paperwork Reduction Act of 1980, 44 U.S.C.
3501 et seq., EPA must submit an information collection request
covering information collection requirements in proposed rules to the
Office of Management and Budget (OMB) for review and approval. This
rule contains no information collection requirements. Therefore,
preparation of an information collection request to accompany this rule
is unnecessary.
E. National Technology Transfer and Advancement Act of 1995
Under Sec. 12(d) of the National Technology Transfer and
Advancement Act (``NTTAA''), the Agency is required to use voluntary
consensus standards in its regulatory activities unless to do so would
be inconsistent with applicable law or otherwise impractical. Voluntary
consensus standards are technical standards (e.g., material
specifications, test methods, sampling procedures, business practice,
etc.) that are developed or adopted by voluntary consensus standard
bodies. Where available and potentially applicable standards are not
used by EPA, the Act requires the Agency to provide Congress, through
the Office of Management and Budget (OMB), an explanation for the
reasons for not using such standards.
Proposal of Method OIA-1677 is the result of a collaborative effort
between OI Analytical, a private sector vendor, and EPA. Method OIA-
1677 applies the innovative technologies of ligand exchange, flow
injection analysis (FIA), and amperometric detection to the
determination of available cyanide, a pollutant regulated under the
Clean Water Act. Approval of Method OIA-1677 would allow use of these
technologies to overcome interference problems commonly encountered in
the determination of available cyanide and would thereby provide more
reliable results for compliance determinations.
EPA's search of the technical literature revealed that there are no
consensus methods for determination of ``available cyanide by flow
injection/ligand exchange/amperometry,'' although ASTM is in the
balloting process for approval of such a method. The ASTM method may
differ slightly from Method OIA-1677. If ASTM approves such a method
prior to final action on today's proposal and EPA determines that the
ASTM method is suitable for compliance monitoring and other purposes,
EPA may take final action to promulgate the ASTM method (without
additional invitation for public comment in the Federal Register) when
the Agency takes final action to promulgate Method OIA-1677 if the ASTM
method ultimately developed does not differ significantly from Method
OIA-1677. EPA invites public comments on the Agency's proposed method
as well as on any other existing, potentially applicable voluntary
consensus standards which the Agency should consider for the
determination of available cyanide or cyanide amenable to chlorination
by flow injection/ligand exchange/amperometry.
F. Executive Order 13045
The Executive Order, ``Protection of Children from Environmental
Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997) applies
to any rule that EPA determines (1) ``economically significant'' as
defined under Executive Order 12866, and (2) concerns an environmental
health or safety risk that EPA has reason to believe may have a
disproportionate effect on children. If the regulatory action meets
both criteria, the Agency must evaluate the environmental health or
safety effects of the planned rule on children; and explain why the
planned regulation is preferable to other potentially effective and
reasonably feasible alternatives considered by the Agency.
EPA interprets the E.O. 13045 as encompassing only those regulatory
actions that are risk based or health based, such that the analysis
required under section 5-501 of the E.O. has the potential to influence
the regulation. This rule is not subject to E.O. 13045 because it does
not involve decisions regarding environmental health or safety risks.
VII. Request for Comments
EPA requests public comments and information on this proposed rule.
Specifically, EPA invites comment on the appropriateness Method OIA-
1677 for cyanide analysis, the utility of Method OIA-1677 for
monitoring, the QC acceptance criteria in Method OIA-1677, and the
comparability of results with CATC methods and results produced by
Method OIA-1677, and EPA's proposed decision not to withdraw other,
existing approved methods for determination of available cyanide by
CATC.
List of Subjects in 40 CFR Part 136
Environmental protection, Analytical methods, Monitoring, Reporting
and record keeping requirements, Waste treatment and disposal, Water
pollution control.
Dated: June 29, 1998.
Carol M. Browner,
Administrator.
In consideration of the preceding, USEPA proposes to amend title
40, chapter I of the Code of Federal Regulations as follows:
PART 136--[AMENDED]
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,
Stat. 1566, et seq. (33 U.S.C. 1251, et seq.) (The Federal Water
Pollution Control Act Amendments of 1972
[[Page 36817]]
as amended by the Clean Water Act of 1977 and the Water Quality Act
of 1987), 33 U.S.C. 1314 and 1361; 86 Stat. 816, Pub. L. 92-500; 91
Stat. 1567, Pub. L. 92-217; Stat. 7, Pub. L. 100-4 (The ``Act'').
2. Section 136.3, paragraph (a), Table IB is amended by revising
entry 24 and adding a new footnote 42 to read as follows:
Sec. 136.3 Identification of test procedures.
(a) * * *
Table IB.--List of Approved Inorganic Test Procedures
--------------------------------------------------------------------------------------------------------------------------------------------------------
Reference (method number or page)
---------------------------------------------------------------------------------------------------------------------
Parameter units and method Standard methods 18th
EPA1,35 ed. ASTM USGS 2 Other
--------------------------------------------------------------------------------------------------------------------------------------------------------
* * * * * * *
24. Available Cyanide, mg/L ..................... 335.14500-CN G....... D2036-91(B) .................... .........................
Cyanide amenable to chlorination
(CATC), Manual distillation with
MgCl2 followed by titrimetry or
spectrophotometry.
Available, Flow injection and ..................... ..................... ..................... .................... OIA-1677.42
ligand exchange, followed by
amperometry.
* * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table IB Notes:
\1\ ``Methods for Chemical Analysis of Water and Wastes'', Environmental Protection Agency, Environmental Monitoring Systems Laboratory-Cincinnati (EMSL-
C1), EPA-600/4-79-020, Revised March 1983 and 1979 where applicable.
\2\ Fishman, M.J., et al, ``Methods for Analysis of Inorganic Substances in Water and Fluvial Sediments,'' U.S. Department of the Interior, Techniques
of Water--Resource Investigations of the U.S. Geological Survey, Denver, CO, Revised 1989, unless otherwise stated.
* * * * * * *
\35\ Precision and recovery statements for the atomic absorption direct aspiration and graphite furnace methods, and for the spectrophotometric SDDC
method for arsenic are provided in Appendix D of the part titled, ``Precision and Recovery Statements for Methods for Measuring Metals''.
* * * * * * *
\42\ Cyanide, Available, Method OIA-1677 (Flow Injection Analysis/Ligand Exchange), ALPKEM, a division of OI Analytical, Box 648, Wilsonville, OR 97070.
* * * * * * *
3. In part 136, appendix A is amended by adding Method OIA-1677
following Method 1625 to read as follows:
Appendix A to part 136--Methods for Organic Chemical Analysis of
Municipal and Industrial Wastewater
* * * * *
Method OIA-1677, November 1997--Available Cyanide by Flow Injection,
Ligand Exchange, and Amperometry
1.0 Scope and Application
1.1 This method is for determination of available cyanide in
water and wastewater by flow injection, ligand exchange, and
amperometric titration. The method is for use in EPA's data
gathering and monitoring programs associated with the Clean Water
Act, Resource Conservation and Recovery Act, Comprehensive
Environmental Response, Compensation and Liability Act, and Safe
Drinking Water Act.
1.2 Cyanide ion (CN-), hydrogen cyanide in water
(HCNaq), and the cyano-complexes of zinc, copper,
cadmium, mercury, nickel, and silver may be determined by this
method (see Section 17.2.1).
1.3 The presence of polysulfides and colloidal material may
prove intractable for application of this method.
1.4 The method detection limit (MDL) is 0.5 g/L and
the minimum level (ML) is 2.0 g/L. The dynamic range is
approximately 2.0 g/L (ppb) to 5.0 mg/L (ppm) cyanide ion
using a 200 L sample loop volume. Higher concentrations can
be determined by dilution of the original sample or by reducing
volume of the sample loop.
1.5 This method is for use by analysts experienced with flow
injection equipment or under close supervision of such qualified
persons.
1.6 The laboratory is permitted to modify the method to
overcome interferences or to lower the cost of measurements,
provided that all performance criteria in this method are met.
Requirements for establishing method equivalency are given in
Section 9.1.2.
2.0 Summary of Method
2.1 The analytical procedure employed for determination of
available cyanide is divided into two parts: sample pretreatment and
cyanide detection. In the pretreatment step, ligand-exchange
reagents are added at room temperature to 100 mL of a cyanide-
containing sample. The ligand-exchange reagents form
thermodynamically stable complexes with the transition metal ions
listed in Section 1.2, resulting in the release of cyanide ion from
the metal-cyano complexes. Cyanide detection is accomplished using a
flow-injection analysis (FIA) system (Reference 15.6). A 200-
L aliquot of the pre-treated sample is injected into the
flow injection manifold of the system. The addition of hydrochloric
acid converts cyanide ion to hydrogen cyanide (HCN) that passes
under a gas diffusion membrane. The HCN diffuses through the
membrane into an alkaline receiving solution where it is converted
back to cyanide ion. The cyanide ion is monitored amperometrically
with a silver working electrode, silver/silver chloride reference
electrode, and platinum/stainless steel counter electrode, at an
applied potential of zero volt. The current generated is
proportional to the cyanide concentration present in the original
sample. Total analysis time is approximately two minutes.
2.2 The quality of the analysis is assured through reproducible
calibration and testing of the FIA system.
2.3 A flow diagram of the FIA system is shown in Figure 1.
BILLING CODE 6560-50-P
[[Page 36818]]
[GRAPHIC] [TIFF OMITTED] TP07JY98.023
BILLING CODE 6560-50-C
3.0 Definitions.
Definitions for terms used in this method are given in the
glossary at the end of the method.
4.0 Interferences.
4.1 Solvents, reagents, glassware, and other sample-processing
hardware may yield artifacts that affect results. Specific selection
of reagents or purification of these reagents may be required.
4.2 All materials used in the analysis shall be demonstrated to
be free from interferences under the conditions of analysis by
running laboratory blanks as described in Section 9.4.
4.3 Glassware is cleaned by washing in hot water containing
detergent, rinsing with tap and reagent water, and drying in an area
free from interferences.
4.4 Interferences extracted from samples will vary considerably
from source to source, depending upon the diversity of the site
being sampled.
4.5 Sulfide is a positive interferent in this method
(References 15.3 and 15.4), because an acidified sample containing
sulfide liberates hydrogen sulfide that is passed through the
membrane and produces a signal at the silver electrode. In addition,
sulfide ion reacts with cyanide ion in solution to reduce its
concentration over time. To overcome this interference, the sulfide
ion must be precipitated with lead ion immediately upon sample
collection. Sulfide ion and lead sulfide react with cyanide ion to
form thiocyanate which is not detected in the analytical system.
Tests have shown (Reference 15.7) that if lead carbonate is used for
sulfide precipitation, the supernate containing cyanide must be
filtered immediately to avoid loss of cyanide through reaction with
precipitated lead sulfide (Section 8.2.1).
4.6 Though not interferences, substances that react with
cyanide should also be removed from samples at time of collection.
These substances include water soluble aldehydes that form
cyanohydrins and oxidants such as hypochlorite and sulfite. Water
soluble aldehydes react with cyanide to form cyanohydrins that are
not detected by the analytical system; hypochlorite and sulfite
oxidize cyanide to non-volatile forms. Procedures for the removal of
these substances are provided in Sections 8.2.2 and 8.2.3.
4.7 Tests conducted using samples containing large amounts of
colloids indicate that cyanide losses are rapid when colloids are
present. Filtration can be used to remove colloids, but may have an
adverse effect on measured cyanide levels. This method should not be
applied to samples with large amounts of colloids unless the
laboratory is able to demonstrate that cyanide concentration
measurements in a sample are not affected by filtration.
5.0 Safety.
5.1 The toxicity or carcinogenicity of each compound or
reagent used in this method has not been precisely determined;
however, each chemical compound should be treated as a potential
health hazard. Exposure to these compounds should be reduced to the
lowest possible level.
5.2 Cyanides and cyanide solutions.
WARNING: The cyanide ion, hydrocyanic acid, all cyanide salts,
and most metal-cyanide complexes are extremely dangerous. As a
contact poison, cyanide need not be ingested to produce toxicity.
Also, cyanide solutions produce fatally toxic hydrogen cyanide gas
when acidified. For these reasons, it is mandatory that work with
cyanide be carried out in a well-ventilated hood by properly trained
personnel wearing adequate protective equipment.
5.3 Sodium hydroxide solutions.
CAUTION: Considerable heat is generated upon dissolution of
sodium hydroxide in water. It may be advisable to cool the container
in an ice bath when preparing sodium hydroxide solutions.
5.4 Unknown samples may contain high concentrations of volatile
toxic compounds. Sample containers should be opened in a hood and
handled with gloves to prevent exposure.
5.5 This method does not address all safety issues associated
with its use. The laboratory is responsible for maintaining a safe
work environment and a current awareness file of OSHA regulations
regarding the safe handling of the chemicals specified in this
method. A reference file of material safety data sheets (MSDSs)
should be available to all personnel involved in these analyses.
Additional information on laboratory safety can be found in
References 15.8 and 15.9.
6.0 Equipment and Supplies
Note: Brand names, suppliers, and part numbers are for
illustrative purposes only. No endorsement is implied. Equivalent
performance may be achieved using apparatus and materials other than
those specified here, but demonstration of equivalent performance
that meets the requirements of this method is the responsibility of
the laboratory.
6.1 Flow injection analysis (FIA) system--ALPKEM Model 3202
(Reference 15.5), or equivalent, consisting of the following:
6.1.1 Injection valve capable of injecting 40 to 300 L
samples.
6.1.2 Gas diffusion manifold with a microporous
Teflon or polypropylene membrane.
6.1.3 Amperometric detection system with:
6.1.3.1 Silver working electrode.
6.1.3.2 Ag/AgCl reference electrode.
6.1.3.3 Pt/stainless steel counter electrode.
6.1.3.4 Applied potential of 0.0 volt.
6.2 Sampling equipment--Sample bottle, amber glass, 1.1-L, with
polytetrafluoroethylene (PTFE)-lined cap. Clean by washing with
detergent and water, rinsing with two aliquots of reagent water, and
drying by baking at 110-150 deg.C for one hour minimum.
6.3 Standard laboratory equipment including volumetric flasks,
pipettes, syringes, etc. all cleaned, rinsed and dried per bottle
cleaning procedure in Section 6.2.
[[Page 36819]]
7.0 Reagents and Standards.
7.1 Reagent water--Water in which cyanide and potentially
interfering substances are not detected at the MDL of this method.
It may be generated by any one of the methods listed below. Reagent
water generated by these methods shall be tested for purity
utilizing the procedure in Section 11.
7.1.1 Activated carbon--Pass distilled or deionized water
through an activated carbon bed (Calgon Filtrasorb-300 or
equivalent).
7.1.2 Water purifier--Pass distilled or deionized water through
a purifier (Millipore Super Q, or equivalent).
7.2 Sodium hydroxide--ACS reagent grade.
7.3 Potassium cyanide--ACS reagent grade.
7.4 Mercury (II) cyanide, 99% purity--Aldrich
Chemical Company Catalog No. 20,814-0, or equivalent.
7.5 Silver nitrate--ACS reagent grade. Aldrich Chemical Company
Catalog No. 20,913-9, or equivalent.
7.6 Hydrochloric acid--approximately 37%, ACS reagent grade.
7.7 Preparation of stock solutions. Observe the warning in
Section 5.2.
7.7.1 Silver nitrate solution, 0.0192 N--Weigh 3.27 g of
AgNO3 into a 1-L volumetric flask and bring to the mark
with reagent water.
7.7.2 Rhodanine solution, 0.2 mg/mL in acetone--Weigh 20 mg of
p-dimethylaminobenzal rhodanine (Aldrich Chemical Co. Catalog No.
11,458-8, or equivalent) in a 100-mL volumetric flask and dilute to
the mark with acetone.
7.7.3 Potassium cyanide stock solution, 1000 mg/L
7.7.3.1 Dissolve approximately 2 g (approximately 20 pellets)
of sodium hydroxide in approximately 500 mL of reagent water
contained in a 1-liter volumetric flask. Observe the caution in
Section 5.3. Add 2.51 g of potassium cyanide (Aldrich Chemical Co.
Catalog No. 20,781-0, or equivalent), dilute to one liter with
reagent water, and mix well. Store KCN solution in an amber glass
container at 0-4 deg.C.
7.7.3.2 Standardize the KCN solution (Section 7.7.3.1) by adding
0.5 mL of rhodanine solution (Section 7.7.2) to 25 mL of KCN
solution and titrating with AgNO3 solution (Section
7.7.1) until the color changes from canary yellow to a salmon hue.
Based on the determined KCN concentration, dilute the KCN solution
to an appropriate volume so the final concentration is 1.00 g/L,
using the following equation:
Equation 1
x x v=1g/L x 1L
Where:
x=concentration of KCN solution determined from titrations
v=volume of KCN solution needed to prepare 1 L of 1 g/L KCN solution
If the concentration is not 1.00 g/L, correct the intermediate
and working calibration concentrations accordingly.
7.7.4 1M sodium hydroxide--Dissolve 40 g of sodium hydroxide
pellets in approximately 500 mL of reagent water in a 1-liter
volumetric flask, observing the caution in Section 5.3. Dilute to
one liter with reagent water. Store in an amber bottle at room
temperature.
7.8 Secondary standards.
7.8.1 Cyanide, 100 mg/L--Dilute 100.0 mL of cyanide stock
solution (Section 7.7.3.2) and 10 mL of 1M sodium hydroxide (Section
7.7.4) to one liter with reagent water (Section 7.1). Store in an
amber glass bottle at 0-4 deg.C.
7.8.2 Cyanide, 10 mg/L--Dilute 10.0 mL of cyanide stock
solution and 10 mL of 1M sodium hydroxide to one liter with reagent
water. Store in an amber glass bottle at 0-4 deg.C.
7.8.3 Cyanide, 1 mg/L--Dilute 1.0 mL of cyanide stock solution
and 1 mL of 1M sodium hydroxide to one liter with reagent water.
Store in an amber glass bottle at 0-4 deg.C.
7.8.4 Cyanide working calibration standard solutions (2--5000
g/L as cyanide)--Working calibration standards may be
prepared to cover the desired calibration range by adding the
appropriate volumes of secondary standards (Sections 7.8.1, 7.8.2,
7.8.3) to 100 mL volumetric flasks that contain 40 mL of reagent
water 7.1) and 1 mL of 1M sodium hydroxide (Section 7.7.4). Dilute
the solutions to 100 mL with reagent water. Prepare working
calibration standards daily. The following table provides the
quantity of secondary standard necessary to prepare working
standards of the specified concentration.
----------------------------------------------------------------------------------------------------------------
Secondary standard solution volume
-----------------------------------------------
Secondary
Secondary Secondary standard
Working calibration standard concentration (g/L) standard standard concentration
concentration concentration (section
(section (section 7.8.1) 100 mg/
7.8.3) 1 mg/L 7.8.2) 10 mg/L L
----------------------------------------------------------------------------------------------------------------
0.000........................................................... .............. .............. ..............
2.0............................................................. 0.200 .............. ..............
5.0............................................................. 0.500 0.050 ..............
10.0............................................................ 1.00 0.100 ..............
50.0............................................................ 5.00 0.500 0.050
100............................................................. 10.0 1.00 0.100
200............................................................. 20.0 2.00 0.200
500............................................................. 50.0 5.00 0.500
1000............................................................ .............. 10.0 1.00
3000............................................................ .............. 30.0 3.00
5000............................................................ .............. 50.0 5.00
----------------------------------------------------------------------------------------------------------------
If desired, the laboratory may extend the analytical working
range by using standards that cover more than one calibration range,
so long as the requirements of Section 10.3 are met.
7.9 Sample Preservation Reagents.
7.9.1 The presence of sulfide may result in the conversion of
cyanide to thiocyanate. While lead acetate test paper has been
recommended for determining the presence of sulfide in samples, the
test is generally unreliable and is typically not usable for sulfide
concentrations below approximately 1 ppm. The use of lead carbonate
(Aldrich Chemical Co. Catalog No. 33,637-8, or equivalent), followed
by immediate filtration of the sample is required whenever sulfide
ion is present. If the presence of sulfide is suspected but not
verifiable from the use of lead acetate test paper, two samples may
be collected, one without lead carbonate addition and another with
lead carbonate addition followed by immediate filtration. Analyze
both samples. If sulfide is present, the preserved sample should
contain higher levels of cyanide than the unpreserved sample. Lead
acetate test paper may be used, but should be tested for minimum
level of sulfide detection by spiking reagent water aliquots with
decreasing levels of sulfide and determining the lowest level of
sulfide detection attainable. The spiked samples are tested with
lead acetate test paper moistened with acetate buffer solution. The
buffer solution is prepared by dissolving 146 g anhydrous sodium
acetate, or 243 g sodium acetate trihydrate in 400 mL of reagent
water, followed by addition of 480 g concentrated acetic acid.
Dilute the solution to 1 L with reagent water. Each new batch of
test paper and/or acetate buffer should be tested to determine the
lowest level of sulfide ion detection prior to use.
7.9.2 Ethylenediamine solution--In a 100 mL volumetric flask,
dilute 3.5 mL pharmaceutical-grade anhydrous ethylenediamine
(Aldrich Chemical Co. Catalog No. 24,072-9, or equivalent) with
reagent water.
7.9.3 Ascorbic acid--Crystals--Aldrich Chemical Co. Catalog No.
26,855-0, or equivalent.
7.10 FIA Reagents.
[[Page 36820]]
7.10.1 Carrier and acid reagent (0.1M hydrochloric acid)--
Dilute 8 mL of concentrated hydrochloric acid to one liter with
reagent water.
7.10.2 Acceptor stock solution (5M sodium hydroxide)--Dissolve
200 grams of sodium hydroxide in 700 mL of reagent water with
stirring, observing the caution in Section 5.3. Dilute to one liter
with reagent water.
7.10.3 Acceptor reagent (0.1M sodium hydroxide)--Dilute 20 mL
of sodium hydroxide solution (Section 7.7.4) to 1000 mL with reagent
water.
7.10.4 Ligand-exchange reagent A-ALPKEM part number A001416, or
equivalent.
7.10.5 Ligand-exchange reagent B-ALPKEM part number A001417, or
equivalent.
7.11 Quality control solutions.
7.11.1 Mercury (II) cyanide stock solution (1000 mg/L as
cyanide)--Weigh 0.486 g of mercury (II) cyanide (Section 7.4) in a
100-mL volumetric flask. Add 10-20 mL of reagent water and 1 mL of
1M sodium hydroxide solution (Section 7.7.4). Swirl to mix. Dilute
to the mark with reagent water.
7.11.2 Laboratory control sample (LCS)--Place 2.00 mL of the
mercury (II) cyanide stock solution (Section 7.11.1) in a 100-mL
volumetric flask and dilute to the mark with reagent water to
provide a final cyanide concentration of 2.00 mg/L.
8.0 Sample Collection, Preservation, and Storage.
8.1 Sample collection and preservation--Samples are collected
using manual (grab) techniques and are preserved immediately upon
collection.
8.1.1 Grab sampling--Collect samples in amber glass bottles
with PTFE-lined caps cleaned according to the procedure in Section
6.2. Immediately after collection, preserve the sample using any or
all of the preservation techniques (Section 8.2), followed by
adjustment of the sample pH to 12 by addition of 1M
sodium hydroxide and refrigeration at 0-4 deg.C.
8.1.2 Compositing--Compositing is performed by combining
aliquots of grab samples only. Automated compositing equipment may
not be used because cyanide may react or degrade during the sampling
period. Preserve and refrigerate each grab sample immediately after
collection (Sections 8.1.1 and 8.2) until compositing.
8.1.3 Shipment--If the sample will be shipped by common carrier
or mail, limit the pH to a range of 12.0-12.3. (See the footnote to
40 CFR 136.3(e), Table II, for the column headed ``Preservation.'')
8.2 Preservation techniques.
8.2.1 Samples containing sulfide ion--Test samples with lead
acetate test paper (Section 7.9.1) to determine the presence or
absence of sulfide ion. If sulfide ion is present, treat the sample
with sufficient solid lead carbonate (Section 7.9.1) to remove
sulfide (as evidenced by lead acetate test paper) and immediately
filter into another sample bottle to remove precipitated lead
sulfide. If sulfide ion is suspected to be present, but its presence
is not detected by this test, two samples should be collected. One
is treated for the presence of sulfide and immediately filtered,
while the second sample is not treated for sulfide. Both samples
must be analyzed by the laboratory. (Tests conducted prior to the
interlaboratory validation of this method showed significant and
rapid losses of cyanides when lead sulfide was allowed to remain in
contact with the sample during holding times of three days and less.
As a result, the immediate filtration of samples preserved with lead
carbonate is essential (Reference 15.6).
8.2.2 Samples containing water soluble aldehydes--Treat samples
containing or suspected to contain formaldehyde, acetaldehyde, or
other water soluble aldehydes with 20 mL of 3.5% ethylenediamine
solution (Section 7.9.2) per liter of sample.
8.2.3 Samples known or suspected to contain chlorine,
hypochlorite, and/or sulfite--Treat with 0.6 g of ascorbic acid
(Section 7.9.3) per liter of sample. EPA Method 330.4 or 330.5 may
be used for the measurement of residual chlorine (Reference 15.1).
8.3 Sample holding time--Maximum holding time for samples
preserved as above is 14 days. Unpreserved samples must be analyzed
within 24 hours, or sooner if a change in cyanide concentration will
occur. (See the footnotes to Table II at 40 CFR 136.3(e).)
9.0 Quality Control.
9.1 Each laboratory that uses this method is required to
operate a formal quality assurance program (Reference 15.9). The
minimum requirements of this program consist of an initial
demonstration of laboratory capability, and the periodic analysis of
LCSs and MS/MSDs as a continuing check on performance. Laboratory
performance is compared to established performance criteria to
determine if the results of the analyses meet the performance
characteristics of the method.
9.1.1 The laboratory shall make an initial demonstration of the
ability to generate acceptable precision and accuracy with this
method. This ability is established as described in Section 9.2.
9.1.2 In recognition of advances that are occurring in
analytical technology, and to allow the laboratory to overcome
sample matrix interferences, the laboratory is permitted certain
options to improve performance or lower the costs of measurements.
Alternate determinative techniques, such as the substitution of
spectroscopic or immuno-assay techniques, and changes that degrade
method performance, are not allowed. If an analytical technique
other than the techniques specified in this method is used, that
technique must have a specificity equal to or better than the
specificity of the techniques in this method for the analytes of
interest.
9.1.2.1 Each time a modification is made to this method, the
laboratory is required to repeat the procedure in Section 9.2. If
the detection limit of the method will be affected by the change,
the laboratory must demonstrate that the MDL is equal to or less
than the MDL in Section 1.4 or one-third the regulatory compliance
level, whichever is greater. If calibration will be affected by the
change, the laboratory must recalibrate the instrument per Section
10.3.
9.1.2.2 The laboratory is required to maintain records of
modifications made to this method. These records include the
information in this subsection, at a minimum.
9.1.2.2.1 The names, titles, addresses, and telephone numbers
of the analyst(s) who performed the analyses and modification, and
of the quality control officer who witnessed and will verify the
analyses and modification.
9.1.2.2.2 A narrative stating the reason(s) for the
modification.
9.1.2.2.3 Results from all quality control (QC) tests comparing
the modified method to this method including:
(a) calibration (Section 10.3)
(b) calibration verification (Section 9.5)
(c) initial precision and recovery (Section 9.2)
(d) analysis of blanks (Section 9.4)
(e) laboratory control sample (Section 9.6)
(f) matrix spike and matrix spike duplicate (Section 9.3)
(g) MDL (Section 1.4)
9.1.2.2.4 Data that will allow an independent reviewer to
validate each determination by tracing the instrument output (peak
height, area, or other signal) to the final result. These data are
to include:
(a) sample numbers and other identifiers
(b) analysis dates and times
(c) analysis sequence/run chronology
(d) sample weight or volume
(e) sample volume prior to each cleanup step, if applicable
(f) sample volume after each cleanup step, if applicable
(g) final sample volume prior to injection (Sections 10 and 11)
(h) injection volume (Sections 10 and 11)
(i) dilution data, differentiating between dilution of a sample
or modified sample (Sections 10 and 11)
(j) instrument and operating conditions
(k) other operating conditions (temperature, flow rates, etc.)
(l) detector (operating condition, etc.)
(m) printer tapes, disks, and other recording of raw data
(n) quantitation reports, data system outputs, and other data
necessary to link raw data to the results reported
9.1.3 Analyses of matrix spike and matrix spike duplicate
samples are required to demonstrate method accuracy and precision
and to monitor matrix interferences (interferences caused by the
sample matrix). The procedure and QC criteria for spiking are
described in Section 9.3.
9.1.4 Analyses of blanks are required to demonstrate freedom
from contamination and that the compounds of interest and
interfering compounds have not been carried over from a previous
analysis. The procedures and criteria for analysis of a blank are
described in Section 9.4.
9.1.5 The laboratory shall, on an ongoing basis, demonstrate
through the analysis of the LCS (Section 7.11.2) that the analysis
system is in control. This procedure is described in Section 9.6.
9.1.6 The laboratory should maintain records to define the
quality of data that is
[[Page 36821]]
generated. Development of accuracy statements is described in
Sections 9.3.8 and 9.6.3.
9.1.7 Accompanying QC for the determination of cyanide is
required per analytical batch. An analytical batch is a set of
samples analyzed at the same time, to a maximum of 10 samples. Each
analytical batch of 10 or fewer samples must be accompanied by a
laboratory blank (Section 9.4), an LCS (Section 9.6), and a matrix
spike and matrix spike duplicate (MS/MSD, Section 9.3), resulting in
a minimum of five analyses (1 sample, 1 blank, 1 LCS, 1 MS, and 1
MSD) and a maximum of 14 analyses (10 samples, 1 blank, 1 LCS, 1 MS,
and 1 MSD) in the batch. If greater than 10 samples are analyzed at
one time, the samples must be separated into analytical batches of
10 or fewer samples.
9.2 Initial demonstration of laboratory capability
9.2.1 Method Detection Limit (MDL)--To establish the ability to
detect cyanide at low levels, the laboratory shall determine the MDL
per the procedure in 40 CFR 136, Appendix B (Reference 15.4) using
the apparatus, reagents, and standards that will be used in the
practice of this method. An MDL less than or equal to the MDL listed
in Section 1.4 must be achieved prior to practice of this method.
9.2.2 Initial Precision and Recovery (IPR)--To establish the
ability to generate acceptable precision and accuracy, the
laboratory shall perform the following operations:
9.2.2.1 Analyze four samples of the LCS (Section 7.11.2)
according to the procedure beginning in Section 10.
9.2.2.2 Using the results of the set of four analyses, compute
the average percent recovery (X) and the standard deviation of the
percent recovery (s) for cyanide. Use Equation 2 for calculation of
the standard deviation of the percent recovery.
Equation 2
[GRAPHIC] [TIFF OMITTED] TP07JY98.024
Where:
n = Number of samples
x = Percent recovery in each sample
9.2.3 Compare s and X with the acceptance criteria specified in
Table 1. If s exceeds the precision limit or X falls outside the
range for recovery, system performance is unacceptable and the
problem must be found and corrected before analyses can begin.
9.3 Matrix spike/matrix spike duplicate (MS/MSD)--The
laboratory shall spike, in duplicate, a minimum of 10 percent of all
samples (one sample in duplicate in each batch of ten samples) from
a given discharge.
9.3.1 The concentration of the spike in the sample shall be
determined as follows:
9.3.1.1 If, as in compliance monitoring, the concentration of
cyanide in the sample is being checked against a regulatory
concentration limit, the spiking level shall be at that limit or at
1 to 5 times higher than the background concentration of the sample
(determined in Section 9.3.2), whichever concentration is higher.
9.3.1.2 If the concentration of cyanide in a sample is not
being checked against a limit, the spike shall be at the
concentration of the LCS or at 1 to 5 times higher than the
background concentration, whichever concentration is higher.
9.3.2 Analyze one sample aliquot out of each set of ten
samples from each discharge according to the procedure beginning in
Section 11 to determine the background concentration (B) of cyanide.
9.3.2.1 Spike this sample with the amount of mercury (II)
cyanide stock solution (Section 7.11.1) necessary to produce a
cyanide concentration in the sample of 2 mg/L. If necessary, prepare
another stock solution appropriate to produce a level in the sample
at the regulatory compliance limit or at 1 to 5 times the background
concentration (per Section 9.3.1).
9.3.2.2 Spike two additional sample aliquots with the spiking
solution and analyze these aliquots to determine the concentration
after spiking (A).
9.3.3 Calculate the percent recovery of cyanide in each aliquot
using Equation 3.
Equation 3
100 (A-B)
p = --------------------
T
Where:
P = Percent recovery
A = Measured concentration of cyanide after spiking
B = Measured background concentration of cyanide
T = True concentration of the spike
9.3.4 Compare the recovery to the QC acceptance criteria in
Table 1. If recovery is outside of the acceptance criteria, and the
recovery of the LCS in the ongoing precision and recovery test
(Section 9.6) for the analytical batch is within the acceptance
criteria, an interference is present. In this case, the result may
not be reported for regulatory compliance purposes.
9.3.5 If the results of both the MS/MSD and the LCS test fail
the acceptance criteria, the analytical system is judged to be out
of control. In this case, the problem shall be identified and
corrected, and the analytical batch reanalyzed.
9.3.6 Calculate the relative percent difference (RPD) between
the two spiked sample results (Section 9.3, not between the two
percent recoveries) using Equation 4.
Equation 4
[GRAPHIC] [TIFF OMITTED] TP07JY98.026
Where:
RPD = Relative percent difference
D1 = Concentration of cyanide in the spiked sample
D2 = Concentration of cyanide in the spiked duplicate
sample
9.3.7 Compare the precision to the RPD criteria in Table 1. If
the RPD is greater than the acceptance criteria, the analytical
system is judged to be out of control, and the problem must be
immediately identified and corrected, and the analytical batch
reanalyzed.
9.3.8 As part of the QC program for the laboratory, method
precision and accuracy for samples should be assessed and records
should be maintained. After the analysis of five spiked samples in
which the recovery passes the test in Section 9.3.4, compute the
average percent recovery (Pa) and the standard deviation
of the percent recovery (sp). Express the accuracy
assessment as a percent recovery interval from Pa -
2sp to Pa + 2sp. For example, if
Pa = 90% and sp = 10% for five analyses, the
accuracy interval is expressed as 70--110%. Update the accuracy
assessment on a regular basis (e.g., after each five to ten new
accuracy measurements).
9.4 Laboratory blanks--Laboratory reagent water blanks are
analyzed to demonstrate freedom from contamination.
9.4.1 Analyze a reagent water blank initially (i.e., with the
tests in Section 9.2) and with each analytical batch. The blank must
be subjected to the same procedural steps as a sample.
9.4.2 If cyanide is detected in the blank at a concentration
greater than the ML, analysis of samples is halted until the source
of contamination is eliminated and a blank shows no evidence of
contamination.
9.5 Calibration verification--Verify calibration of the
analytical equipment before and after each analytical batch of 14 or
fewer measurements. (The 14 measurements will normally be 10
samples, 1 reagent blank, 1 LCS, 1 MS, and 1 MSD). Verification is
accomplished by analyzing the mid-range calibration standard and
verifying that it is within the QC acceptance criteria for recovery
in Table 1. (The concentration of the calibration verification
depends on the calibration range being used.) Failure to verify
calibration within the acceptance criteria requires recalibration of
the analysis system.
9.6 Laboratory control sample (LCS)--To demonstrate that the
analytical system is in control, and acceptable precision and
accuracy is being maintained with each analytical batch, the
laboratory shall perform the following operations.
9.6.1 Analyze a LCS (Section 7.11.2) with each analytical batch
according to the procedure in Section 10.
9.6.2 If the results for the LCS are within the acceptance
criteria specified in Table 1, analysis of the batch may continue.
If, however, the concentration is not within this range, the
analytical process is not in control. In this event, correct the
problem, repeat the LCS test, and reanalyze the batch.
9.6.3 The laboratory should add results that pass the
specification in Section 9.6.2 to IPR and previous LCS data and
update QC charts to form a graphic representation of continued
laboratory performance. The laboratory should also develop a
statement of laboratory data quality for cyanide by calculating the
average percent recovery (R) and the standard deviation of the
percent recovery (Sr). Express the accuracy as a recovery
interval from R - 2sr to R + 2sr. For example,
if R = 95% and sr = 5%, the accuracy is 85% to 105%.
9.7 Reference Sample--To demonstrate that the analytical system
is in control, the
[[Page 36822]]
laboratory should periodically test an external reference sample,
such as a Standard Reference Material (SRM) if an SRM is available
from the National Institutes of Standards and Technology (NIST). The
reference sample should be analyzed quarterly, at a minimum.
Corrective action should be taken if the measured concentration
significantly differs from the stated concentration.
10.0 Calibration and Standardization.
This section describes the procedure to calibrate and
standardize the FIA system prior to cyanide determination.
10.1 Instrument setup.
10.1.1 Set up the FIA system and establish initial operating
conditions necessary for determination of cyanide. If the FIA system
is computerized, establish a method for multi-point calibration and
for determining the cyanide concentration in each sample.
10.1.2 Verify that the reagents are flowing smoothly through
the FIA system and that the flow cell is purged of air bubbles.
10.2 Instrument Stabilization
10.2.1 Load a 10 mg/L KCN standard (Section 7.8.2) into the
sampling valve and inject into the FIA system.
10.2.2 Continue to inject 10 mg/L KCN standards until 3
successive peak height or area results are within 2% RSD, indicating
that the electrode system is stabilized.
10.2.3 Following stabilization, inject the highest
concentration calibration standard until 3 successive peak height or
area results are within 2% RSD indicating stabilization at the top
of the calibration range.
10.3 External standard calibration.
10.3.1 Inject each of a minimum of 3 calibration standards. One
of the standards should be at the minimum level (ML) unless
measurements are to be made at higher levels. The other
concentrations should correspond to the expected range of
concentrations found in samples or should define the working range
of the FIA system.
10.3.2 Using injections of a constant volume, analyze each
calibration standard according to Section 11 and record peak height
or area responses against the concentration. The results can be used
to prepare a calibration curve. Alternatively, if the ratio of
response to amount injected (calibration factor) is constant over
the working range (<10% RSD), linearity through the origin can be
assumed and the averaged calibration factor (area/concentration) can
be used in place of a calibration curve.
11.0 Procedure.
This section describes the procedure for determination of
available cyanide using the FIA system.
11.1 Analysis of standards, samples, and blanks.
11.1.1 Ligand-exchange reagent treatment of standards, samples,
and blanks.
11.1.2 To 100-mL of cyanide-containing sample (or standard or
blank) at pH of approximately 12, add 100 L of ligand-
exchange reagent Part B (Section 7.10.5), 50 L of ligand-
exchange reagent Part A (Section 7.10.4), and mix thoroughly. Load
the sample, standard, or blank into the sample loop.
Note: The ligand-exchange reagents, when added to 100 mL of
sample at the specified volume, will liberate cyanide from metal
complexes of intermediate stability up to 5 mg/L cyanide ion. If
higher concentrations are anticipated, add additional ligand-
exchange reagent, as appropriate, or dilute the sample.
11.1.3 Inject the sample and begin data collection. When data
collection is complete, analyze the next sample, standard or blank
in the batch until analyses of all samples in the batch are
completed.
12.0 Data Analysis and Calculations.
12.1 Calculate the concentration of material in the sample,
standard or blank from the peak height or area using the calibration
curve or calibration factor determined in Section 10.3.
12.2 Reporting.
12.2.1 Samples--Report results to three significant figures for
cyanide concentrations found above the ML (Section 1.4) in all
samples. Report results below the ML as <5 mg/L, or as required by
the permitting authority or permit.
12.2.2 Blanks--Report results to three significant figures for
cyanide concentrations found above the MDL (Section 1.3). Do not
report results below the MDL unless required by the permitting
authority or in the permit.
13.0 Method Performance.
13.1 Method detection limit (MDL)--MDLs from nine laboratories
were pooled to develop the MDL of 0.5 g/L given in Section
1.4 (Reference 15.12).
13.2 Data obtained from single laboratory testing of the method
are summarized in Table 2 and show recoveries and reproducibility
for ``free'' forms of cyanide, including the recovery and
reproducibility of silver, nickel, mercurous and mercuric cyanide
species. Determination of these species tends to be problematic with
other methods for the determination of available cyanide. As it is
the case with other methods used for available cyanide, iron cyanide
species were not recovered and recoveries for gold and cobalt
species were zero or very low. The complete results from the single
laboratory study are available in the Report of the Draft OIA Method
1677 Single Laboratory Validation Study (Reference 15.11).
13.3 Listed in Table 1 are the QC acceptance criteria developed
from an interlaboratory validation study of this method. This study
was conducted following procedures specified in the Guide to Method
Flexibility and Approval of EPA Water Methods (Reference 15.10). In
this study, a total of nine laboratories performed analyses for
various water matrices. Table 3 shows a summary of the
interlaboratory results which include the accuracy and precision
data as % recoveries and relative standard deviations. In addition
to spikes of easily dissociable cyanides, some samples contained
known amounts of cyanides that are not recoverable (e.g., Pt and Fe
complexes) and thiocyanate was spiked to one sample to investigate
the potential for interference. The complete study results are
available in the Report of the Draft OIA Method 1677 Interlaboratory
Validation Study (Reference 15.12).
14.0 Pollution Prevention and Waste Management.
14.1 It is the laboratory's responsibility to comply with all
federal, State, and local regulations governing waste management,
particularly the hazardous waste identification rules and land-
disposal restrictions. In addition, it is the laboratory's
responsibility to protect air, water, and land resources by
minimizing and controlling all releases from fume hoods and bench
operations. Also, compliance is required with any sewage discharge
permits and regulations.
14.2 Samples containing cyanide, certain metals, and acids at a
pH of less than 2 are hazardous and must be treated before being
poured down a drain or must be handled as hazardous waste.
14.3 For further information on waste management, consult Less
is Better: Laboratory Chemical Management for Waste Reduction,
Section 15.8.
15.0 References.
15.1 Environmental Monitoring Systems Laboratory. EPA Method
335.1. In: Methods for the Chemical Analysis of Water and Wastes
(EPA/600/4-79-020). Environmental Protection Agency, Cincinnati,
Ohio. Revised March 1983.
15.2 American Public Health Association, American Waterworks
Association, Water Pollution Control Board. Methods Section 4500-CN
in Standard Methods for the Examination of Water and Wastewater,
19th Edition. American Public Health Association, Washington, DC,
1995.
15.3 Ingersol, D.; Harris, W.R.; Bomberger, D.C.; Coulson, D.M.
Development and Evaluation Procedures for the Analysis of Simple
Cyanides, Total Cyanides, and Thiocyanate in Water and Waste Water
(EPA-600/4-83-054), 1983.
15.4 Code of Federal Regulations, Title 40, Part 136, Appendix
B. U.S. Government Printing Office, Washington, D.C., 1994.
15.5 ALPKEM CNSolution Model 3202 Manual. Available from
ALPKEM, a division of OI Analytical, Box 648, Wilsonville, OR 97070.
15.6 Milosavljevic, E.B.; Solujic, L.; Hendrix, J.L.
Environmental Science and Technology, Vol. 29, No. 2, 1995, pp 426-
430.
15.7 Wilmont, J.C.; Solujic, L.; Milosavljevic, E. B.; Hendrix,
J.L.; Reader, W.S. Analyst, June 1996, Vol. 121, pp 799-801.
Formation of Thiocyanate During Removal of Sulfide as Lead Sulfide
Prior to Cyanide Determination.
15.8 Less is Better: Laboratory Chemical Management for Waste
Reduction. Available from the American Chemical Society, Department
of Government Regulations and Science Policy, 1155 16th Street, NW,
Washington, DC 20036.
15.9 Handbook for Analytical Quality Control in Water and
Wastewater Laboratories (EPA-600/4-79-019), USEPA, NERL, Cincinnati,
Ohio 45268 (March 1979).
15.10 Guide to Method Flexibility and Approval of EPA Water
Methods, December, 1996, (EPA-821-D-96-004). Available from the
National Technical Information Service (PB97-117766).
15.11 Report of the Draft OIA Method 1677 Single Laboratory
Validation Study, November 1996. Available from ALPKEM, a division
of OI Analytical, Box 648, Wilsonville, OR 97070.
[[Page 36823]]
15.12 Report of the Draft OIA Method 1677 Interlaboratory
Validation Study, March 1997. Available from ALPKEM, a division of
OI Analytical, Box 648, Wilsonville, OR 97070.
16.0 Tables
Table 1.--Quality Control Acceptance Criteria
------------------------------------------------------------------------
Required
Criterion recovery range Precision
(%)
------------------------------------------------------------------------
Initial precision and recovery.......... 92-122 <5.1% RSD
Ongoing precision and recovery
(Laboratory control sample)............ 82-132 N/A
Calibration verification................ 86-118 N/A
Matrix spike/matrix spike duplicate..... 82-130 <11% RPD
------------------------------------------------------------------------
Table 2.--Species-Dependent Cyanide Recoveries Using Draft Method 1677
\1\
------------------------------------------------------------------------
0.20 g/mL CN- m>g/mL CN-
------------------------------------------------------------------------
[Zn(CN)4]2-................................. 97.4 (0.7) 98.5 (0.7)
[Cd(CN)4]2-................................. 100.0 (0.8) 100.0 (0.2)
[Cu(CN)4]2-................................. 100.9 (1.3) 99.0 (0.6)
[Ag(CN)4]3-................................. 101.8 (0.9) 100.0 (0.5)
[Ni(CN)4]2-................................. 104.3 (0.2) 103.0 (0.5)
[Hg(CN)4]2-................................. 100.0 (0.6) 99.0 (0.3)
Hg(CN)2..................................... 103.4 (0.4) 98.0 (0.3)
[Fe(CN)4]4-................................. 0.0 0.0
[Fe(CN)6]3-................................. 0.0 0.0
[Au(CN)2]-.................................. \2\ 1.3
(0.0) 0.0
[Co(CN)6]3-................................. \2\ 2.9
(0.0) \2\ 2.0
(0.0)
------------------------------------------------------------------------
\1\ Values are % recoveries; numbers in parentheses are percent relative
standard deviations.
\2\ Commercial product contains some free cyanide.
Table 3.--Cyanide Recoveries From Various Aqueous Matrices
----------------------------------------------------------------------------------------------------------------
Sample CN Average %
Sample concentration Added CN1 concentration recovery % RSD
----------------------------------------------------------------------------------------------------------------
Reagent water w/0.01M NaOH........ 0 g/L 100 g/L as KCN.. 108 4.0
POTW secondary effluent........... 3.0 g/L 100 g/L as KCN; 102 7.0
2 mg/L as [Pt(CN)6]4-.
Petroleum Refinery Secondary 9.9 g/L 2 mg/L as KCN; 5 mg/L as 87 21
Effluent. [Fe(CN)6]4-.
Coke Plant Secondary Effluent..... 14.0 g/L 50 g/L as KCN... 95 4.0
Rolling Mill Direct Filter 4.0 g/L None..................... 80 41
Effluent.
Metals Finishing Indirect Primary 1.0 g/L 200 g/L as KCN; 92 16
Effluent. 2 mg/L as KSCN.
Reagent water w/0.01M NaOH........ 0 g/L 200 g/L as KCN.. 101 8.0
Reagent water w/0.01M NaOH........ 0 g/L 10 mg/L as KCN; 10 mg/L 103 2.0
as [Pt(CN)6]4-.
Mining Tailing Pond Effluent...... 842 g/L 4 mg/L as KCN............ 98 3.0
----------------------------------------------------------------------------------------------------------------
\1\ Cyano-complexes of Pt and Fe were added to the POTW and petroleum refinery effluents, respectively; and
thiocyanate was added to the metals finishing effluent to demonstrate that the FI/LE system does not determine
these forms of cyanide.
17.0 Glossary of Definitions and Purposes.
The definitions and purposes are specific to this method but
have been conformed to common usage as much as possible.
17.1 Units of weights and measures and their abbreviations
17.1.1 Symbols.
deg.C degrees Celsius
% percent
plus or minus
greater than or equal to
17.1.2 Alphabetical characters.
g gram
L liter
mg milligram
mg/L milligram per liter
g microgram
g/L microgram per liter
mL milliliter
ppm parts per million
ppb parts per billion
M molar solution
17.2 Definitions.
17.2.1 Available cyanide consists of cyanide ion
(CN-), hydrogen cyanide in water (HCNaq) and
the cyano-complexes of zinc, copper, cadmium, mercury, nickel, and
silver.
17.2.2 Calibration blank--A 100 mL volume of reagent water
treated with the ligand-exchange reagents and analyzed using the FIA
procedure.
17.2.3 Calibration standard (CAL)--A solution prepared from the
dilution of stock standard solutions. A 100 mL aliquot of each of
the CALs are subjected to the analysis procedure. The resulting
observations are used to calibrate the instrument response with
respect to the analyte concentration.
17.2.4 Discharge--Specific discharge (also known as ``matrix
type'') means a sample medium with common characteristics across a
given industrial category or industrial subcategory. Examples
include: C-stage effluents from chlorine bleach mills in the Pulp,
Paper, and Paperboard industrial category; effluent from the
continuous casting subcategory of the Iron and Steel industrial
category; publicly owned treatment work (POTW) sludge; and in-
process streams in the Atlantic and Gulf Coast Hand-shucked Oyster
Processing subcategory. Specific discharge also means a discharge
with characteristics different from other discharges. Therefore, if
there are multiple discharges from a facility all with the same
characteristics, these are the same discharge for the purpose of
demonstrating equivalency of a method modification. In this context,
``characteristics'' means that results of the matrix spike and
matrix spike duplicate (MS/MSD) tests with the unmodified method
meet the QC acceptance criteria for recovery and relative percent
difference (RPD).
[[Page 36824]]
17.2.5 Initial precision and recovery (IPR)--Four aliquots of
the LRB spiked with the analytes of interest and used to establish
the ability to generate acceptable precision and accuracy. An IPR is
performed the first time this method is used and any time the method
or instrumentation is modified.
17.2.6 Laboratory control sample (LCS)--An aliquot of LRB to
which a quantity of mercury (II) cyanide stock solution is added in
the laboratory. The LCS is analyzed like a sample. Its purpose is to
determine whether the methodology is in control and whether the
laboratory is capable of making accurate and precise measurements.
17.2.7 Laboratory reagent blank (LRB)--An aliquot of reagent
water that is treated like a sample including exposure to all
glassware, equipment, and reagents that are used with other samples.
The LRB is used to determine if the method analyte or other
interferences are present in the laboratory environment, reagents,
or apparatus.
17.2.8 Matrix spike/matrix spike duplicate (MS/MSD)--An aliquot
of an environmental sample to which a quantity of the method analyte
is added in the laboratory. MS/MSDs are analyzed like a sample.
Their purpose is to determine whether the sample matrix contributes
bias to the analytical results. The background concentration of the
analyte in the sample matrix must be determined in a separate
aliquot and the measured values in the MS/MSD corrected for the
background concentration.
17.2.9 Minimum level (ML)--The level at which the entire
analytical system shall give a recognizable signal and acceptable
calibration point, taking into account method specific sample and
injection volumes.
17.2.10 Ongoing Precision and Recovery (OPR)--See Laboratory
control sample.
[FR Doc. 98-17963 Filed 7-6-98; 8:45 am]
BILLING CODE 6560-50-P