&EPA
United States
Environmental Protection
Agency
Office of Research and
Development
Washington DC 20460
EPA/600/R-94/173
October 1994
Technical Notes on
Drinking Water
Methods
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EPA/600/R-94/173
October 1994
TECHNICAL NOTES
on
DRINKING WATER METHODS
U. S. Environmental Protection Agency
Office of Water
Office of Ground Water and Drinking Water
Office of Research and Development
Environmental Monitoring Systems Laboratory
Cincinnati, OH 45268
Printed on Recycled Paper
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DISCLAIMER
This manual has been reviewed by the Technical Support Division, Office
of Water and the Environmental Monitoring Systems Laboratory - Cincinnati,
U.S. Environmental Protection Agency, and approved for publication. Mention
of trade names or commercial products does not constitute endorsement or
recommendation for use.
11
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FOREWORD
Compliance with National Primary and Secondary Drinking Water Regulations
requires that analyses of samples be conducted by a certified laboratory. A
certification condition is that an approved method be used. The Office of
Water's (OW) Technical Support Division (TSD) prepares the analytical methods
parts of drinking water regulations. The Office of Research and Development's
(ORD) Environmental Monitoring Systems Laboratory at Cincinnati, Ohio (EMSL-
Cincinnati) conducts research to develop and evaluate analytical methods for
the determination of contaminants in many media including drinking water.
EMSL-Cincinnati also regularly publishes methods for use in drinking water
compliance monitoring.
This joint OW/ORD publication, Technical Notes on Drinking Water Methods.
was prepared to add modifications, clarifications, options or improvements to
methods that have been previously approved and published. To allow the public
to use these changes without waiting for incorporation in the next revision of
a method, EPA has elected to describe the changes in this document. The
Office of Water will approve these changes in a 1994 rulemaking by
incorporating Technical Notes on Drinking Water Methods into the drinking
water regulations. Procedures described herein supersede or complement
procedures described in the approved methods. When a method is revised,
relevant procedures from this document will be included in the revised method.
We are pleased to provide these technical notes and believe they will be
of considerable value to public and private laboratory, regulatory and
certification personnel. 1
Alan A. Stevens, Director
Technical Support Division
Office of Water
Thomas Clark, Director
Environmental Monitoring Systems
Laboratory - Cincinnati
m
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Table of Contents
TITLE PAGE
Disclaimer . .ii
Foreword '. , i i i
Acknowledgments vi
Introduction vii
I. Approved Drinking Water Methods for Compliance Monitoring... 1
II. Methods To Be Withdrawn on July 1, 1996 14
III. Recommended Methods for Secondary Drinking Water Contaminants 20
IV. Mandatory Method Modifications 22
Standard Method 4500-C1-E (Chlorine Residuals) 23
Standard Method 4500-C1-G (Chlorine Residuals) ..24
Protocol for Continuous Chlorine Residual Monitoring ...25
Spectrophotometric Determinations of Cyanide 26
Turbidimeter Calibration 28
Sample Digestion for Determination of Metal Contaminants 29
Standard Method 3114B (Arsenic and Selenium) 30
Standard Method 3113B and ASTM D3859-93B (Selenium) 31,
Standard Method 3113B (Chromium) 32
EPA Methods 502.2 and 524.2, Sorbent Traps . 33
EPA Methods 502.2, 524.2 and 551, Sample Acidification 34
EPA Method 506, Errata in Summary 35
EPA Method 508, DCPA and Hexachlorocyclopentadiene -...36
EPA Methods 515.1 and 515.2, Use of TMSD 37
iv
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Table of Contents
TITLE
PAGE
IV. Mandatory Method Modifications (Continued)
EPA Method 524.2, Quality Assurance, VOC Data L... 40
EPA Method 531.1 and SM 6610, Storage of Samples..... 44
EPA Method 551, Pentane 45
EPA Method 549.1, Sample Containers ...46
Alternative Liquid-Solid Extraction Cartridges ancj Disks......47
V. Recommended Method Modifications 48
EPA Method 100.1, Asbestos Guidance 49
EPA Method 502.2, Use of the PID :.. 52
EPA Methods 502.2, 524.2 and 551, Sample Dechlorination ..53
EPA Method 504.1, Chromatographic Interferences ..54
EPA Methods 505, 507, 508, Interchange of Detectors....... 56
EPA Methods 507, 508 and 515.1, Mercuric Chloride, .......57
EPA Method 1613, Dioxin Guidance. .58
VI. EPA Contacts and Method References 59
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ACKNOWLEDGMENTS
We appreciate the many constructive comments and informative questions
from our customers, the analytical and certification laboratory community.
Their information provided the basis for the options, clarifications and
method modifications that are approved and described in these technical notes.
Many people in the Office of Research and Development's Environmental
Monitoring Systems Laboratory - Cincinnati (EMSL-Cincinnati) and in the Office
of Ground Water and Drinking Water's Technical Support Division (TSD) in
Cincinnati contributed to these notes. The EPA scientists in these groups
used information from their many contacts with the public, and their years of
experience with drinking water analysis to produce this publication.
Technical Notes was developed and edited by Richard Reding of TSD who wishes
to especially acknowledge the contributions of Thomas Behymer, James
Eichelberger, Theodore Martin, Jean Munch, James O'Dell, John Pfaff, Jody
Shoemaker and Nancy Ulmer from EMSL-Cincinnati, Patricia Snyder Fair, Marianne
Feige, Edward Click, David Munch and Kent Sorrel 1 from TSD, and Patrick Clark
from the Risk Reduction Engineering Laboratory in Cincinnati. Carol Madding,
TSD, contributed technical notes and helped with the editorial design. In
addition, the names of the developers of the methods and instrumentation that
are the subject of this publication can be found in the acknowledgment and
reference sections of the EPA method or EPA methods manual.
The administrative personnel of EMSL-Cincinnati, in particular Diane
Schirmann, Patricia Hurr, and Helen Brock, provided outstanding support to
this effort. The editor also thanks the administrators and managers of the
Environmental Protection Agency who supported the development and preparation
of this document. Special appreciation is due to Herbert J. Brass, Chief of
the Drinking Water Quality Assessment Branch, TSD, and William L. Budde,
Director of the Chemistry Research Division, EMSL-Cincinnati, for their
cooperation and support during this project.
VI
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INTRODUCTION
Richard Reding
This document, Technical Notes on Drinking Water Methods, describes
method modifications that were; developed after an approved method had been
published. Most of the modifications were formerly footnoted in the drinking
water regulations, or were described in a proposed rule (58 FR 65622, December
15, 1993). Because this document is incorporated by reference in drinking
water regulations, it is a mandatory part of the analytical procedures
required to conduct compliance monitoring and to obtain laboratory
certification. Laboratories can use this publication as a guide to analytical
methods approved under the Safe Drinking Water Act (SDWA), to obtain
information on the latest approved modifications to these methods, and to
contact EPA with questions about drinking water methods. Since EPA method
manuals are printed in a looseleaf format, the format of Technical Notes
allows readers to insert pages containing a method change in the manual
containing the affected EPA analytical method.
Methods approved for monitoring under National Primary Drinking Water
Regulations are in Section I of this document. Methods for which approval
will be withdrawn in 1996 are 'in Section II, and methods for monitoring under
National Secondary Drinking Water Regulations are contained in Section III.
Mandatory method modifications are described in Section IV. The modifications
include a protocol for monitoring chlorine residuals continuously as required
under the Surface Water Treatment Rule, requirements for mandatory manual
distillation of samples collected for determination of cyanide, and use of
another derivatizing reagent with EPA Methods 515.1 and 515.2. Technical
notes on optional procedures and recommended modifications to compliance
methods are described in Section V. These notes include guidance on how to
make analyses of asbestos and dioxin more cost-effective, and when to omit use
of mercuric chloride in some EPA pesticide methods., The remainder of this
introduction provides guidance on methods selection and on|the laboratory
certification aspects of approved methods. i
SELECTION OF METHODS FOR OTHER CHEMICALS
EPA believes that some water systems wish to measure chemicals that are
not included in drinking water regulations, and need advice on what method to
use. The December 1993 Proposal noted that while EPA only approves methods
for contaminants regulated under the SDWA, the Agency encourages laboratories
to use these methods for voluntary monitoring of other contaminants, "if the
method description specifically includes these, contaminants." This
recommendation does not preclude use of other methods, including test kits,
for voluntary monitoring. Analysts always should carefully evaluate the
performance of any method when using it for samples other than compliance
monitoring samples, or for contaminants not regulated under the SDWA.
vii
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LABORATORY CERTIFICATION
When 'using an approved method to obtain certification or to conduct
compliance monitoring, EPA strongly encourages users of methods that are
published in an EPA manual to follow instructions contained in the
introductions to these manuals, unless the instructions conflict with
statements in this document, or in the drinking water regulations. Although
"must" can be argued to be a stronger word than "should" in requiring
adherence to method procedures, some approved methods use these terms
interchangeably. Analytical methods for drinking water are written to be
prescriptive enough to provide uniformity of data quality, and flexible enough
to allow analysts to exercise judgment, skill and initiative to improve the
overall quality and efficiency of compliance monitoring. The Agency does not
believe that semantical differences between "must" or "should" limits the
authority of certification officials to enforce provisions of the methods.
vm
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SECTION I. APPROVED DRINKING WATER METHODS FOR COMPLIANCE MONITORING
To make this document a more complete source of current methods
information, the approved methods which are specified in regulations at 40 CFR
Part 141, are listed in this section. Methods for which approval will be
withdrawn in 1996 are in Section II. Recommended methods for secondary
contaminant monitoring, which are specified in regulations at 40 CFR Part 143
are listed in Section III. '
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METHODS FOR COLIFORM SAMPLING
To comply with the provisions of the Total Coliform Rule, public water
systems must conduct analyses in accordance with one of the analytical methods
in the following table. Total coliform methods, except for the Colisure Test,
are contained in the 18th edition of Standard Methods for the Examination of
Water and Wastewater, 1992, American Public Health Association, 1015 Fifteenth
Street NW, Washington, D.C. 20005. Preparation of the EC medium and the
nutrient agar are described in Standard Methods, p. 9-52, para, la, and pp. 9-
47 to 9-48, respectively. A description of the Colisure Test may be obtained
from the Millipore Corporation, Technical Services Department, 80 Ashby Road,
Bedford, MA 01730. The phone number is (800) 645-5476.
Organism
Methodology
Citation
Total Col i forms1
Total Coliform Fermentation
Technique2' '
Total Coliform Membrane Filter
Technique
Presence-Absence (P-A) Coliform
Test4'5
ONPG-MUG Test6
Col i sure Test7
9221A, B
9222A, B, C
9221D
9223
Footnotes .-•
1 The time from sample collection to initiation of analysis may not exceed 30
hours.
Lactose broth, as commercially available, may be used in lieu of lauryl
tryptose broth, if the system conducts at least 25 parallel tests between this
medium and lauryl tryptose broth using the water normally tested, and this
comparison demonstrates that the false-positive rate for total coliforms,
using lactose broth, is less than 10 percent.
3 If inverted tubes are used to detect gas production, the media should cover
these tubes at least one-half to two-thirds after the sample is added.
4 No requirement exists to run the completed phase on 10 percent of all total
coliform-positive confirmed tubes.
Six-times formulation strength may be used if the medium is filter-
sterilized rather than autoclaved. .
6 The ONPG-MUG Test is also known as the Autoanalysis Colilert System.
7 The Colisure Test must be incubated for 28 hours before examining the
results. If examination at 28 hours is not convenient, then results may be
examined at any- time between 28 hours and 48 hours.
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molybdate blue;
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hod for
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oupled plasma 200. 73
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d) id >
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oupled plasma 200. 73
tion; direct aspiration
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-------
Footnotes
Annual Book of ASTM Standards, Vols. 11. 01 and 11.02, American Society
?oLTef^?g and Materials> 1916 Race Street, Philadelphia, PA 19103.
18th edition of Standard Methods for the Examination Of water and
Wastewater, 1992, American Public Health Association, 1015 Fifteenth
Street NW, Washington, D.C. 20005.
"Methods for the Determination of Metals in Environmental Samples -
Supplement I", EPA-600/R-94/111, May 1994. Available at NTIsT PB94-
>LO ~t i? ~r & •
Method 100.1, "Analytical Method For Determination of Asbestos Fibers in
Water," EPA-600/4-83-043, September 1983. Available at NTIS, PB83-
260471.
Method 100.2, "Determination Of Asbestos Structures Over 10 urn in Lenath
in Drinking Water," EPA/600/R-94/134, June 1994. Available at NTIS,
*- JD I? TC ^m £ \J _1_ _x \J £ •
Available from Books and OperPFile Reports" Sect ion, U.S. Geological
Survey, Federal Center, Box 25425, Denver, CO 80225-0425
"Methods for the Determination of Inorganic Substances in Environmental
Samples," EPA-600/R-93/100, August 1993. Available at NTIS, PB94-
12 18 11 .
Industrial Method No. 129-71W, "Fluoride in Water emd Wastewater «
December 1972, and Method No. 380-75WE, "Fluoride In Water and '
" February 1976' Technicon Industrial Systems, Tarrytown, NY
Methods 150.1, 150.2 and 245.2 are available from USEPA, EMSL-
Cincinnati, OH 45268. The identical methods are also in "Methods for
Chemical Analysis of Water and Wastes," EPA-600/4-79/020, March 1983
Method B-1011, "Waters Test Method for Determination of NiSite/Hitrite
in Water Using Single Column Ion Chromatography," Millipore Corporation,
Waters Chromatography Division, 34 Maple Street, Milford, MA 01757
Technical Bulletin 601 "standard Method of Test for Nitrate in Drinkina
OPlJg'" JhK ^'^ 2?1890.:0°1< ATI Orion, 529 Main Street, Boston, MA
02129. This method is identical to Orion WeWWG/5880, which is approved
for nitrate analysis. ATI Orion republished the method in 1994, and
renumbered it as 601, because the 1985 manual "Orion Guide to Water and
Wastewater Analysis," which contained WeWWG/5880, is no loncrer
available.
-------
METHODS FOR ORGANIC CHEMICALS
Analyses for regulated organic contaminants under the monitoring
requirements specified at §§141.24 and 141.30 shall be conducted using the
following EPA methods or their equivalent as approved by EPA. Other mandatory
and optional procedures for conducting these methods are described in Sections
IV and V, respectively, of this document.
Contaminant
Benzene
Carbon tetrachloride
Chlorobenzene
1,2-Di chlorobenzene
1,4-Dichlorobenzene
1,2-Dichloroethane
ci s-Di chloroethylene
trans-Di chloroethylene
Dichloromethane
1,2-Dichloropropane
Ethyl benzene
Styrene
Tetrachloroethylene
1,1,1-Tri chloroethane
Trichloroethylene
Toluene
1,2,4-Tri chlorobenzene
1,1-Di chloroethylene
1,1,2-Tri chloroethane
Vinyl chloride
Xylenes (total)
2,3,7,8-TCDD (dioxin)
2,4-D
2,4,5-TP (Silvex)
Alachlor
Atrazine
Benzo(a)pyrene
Carbofuran
Chlordane
Dalapon
Di(2-ethylhexyl)adi pate
Di(2-ethylhexyl)phthalate
Dibromochloropropane (DBCP)
Dinoseb
Diquat
Endothall
Endrin
Ethylene dibromide (EDB)
Glyphosate
Heptachlor
Heptachlor Epoxide
Method
502.2, 524.2
502.2, 524.2, 551
502.2, 524.2
502.2, 524.2
502.2, 524.2
502.2, 524.2
502.2, 524.2
502.2, 524.2
502.2, 524.2
502.2, 524.2
502.2, 524.2
502.2, 524.2
502.2, 524.2, 551
502.2, 524.2, 551
502.2, 524.2, 551
502.2, 524.2
502.2, 524.2
502.2, 524.2
502.2, 524.2
502.2, 524.2
502.2, 524.2
1613
515.2, 555, 515.1
515.2, 555, 515.1
5051, 507, 525.2, 508.1
5051, 507, 525.2, 508.1
525.2, 550, 550.1
531.1, 6610
505, 508, 525.2, 508.1
552.1, 515.1
506, 525.2
506, 525.2
504.1, 551
515.2, 555, 515.1
549.1
548.1
505, 508, 525.2, 508.1
504.1 551
547, 6651
505, 508, 525.2, 508.1
505, 508, 525.2, 508.1
-------
Contaminant
Method
Hexachlorobenzene
Hexachlorocyclopentadiene
Lindane
Methoxychlor
Oxamyl
PCBs (as decachlorobiphenyl)2
(as Aroclors)
Pentachlorophenol
Picloram
Simazine
Toxaphene
Total Tribalomethanes
505, 508, 525.2, 508.1
505, 525.2, 508, 508.1
505, 508, 525.2, 508.1
505, 508, 525.2, 508.1
531.1, 6610
508A
505, 508
515.2, 525.2, 555, 515.1
515.2, 555, 515.1
5051, 507, 525.2, 508.1
505, 508, 525.2
502.2, 524.2, 551
Footnotes '
1 A nitrogen-phosphorous detector should be substituted for the electron
capture detector in Method 505 (or another approved method should be used) to
determine alachlor, atrazine and simazine, if lower detection limits are
required. ;
2 PCBs are qualitatively identified as Aroclors and measured for compliance
purposes as decachlorobiphenyl using Method 508A. '
Methods 502.2, 505, 507, 508, 508A, 515.1 and 531.1 are in Methods for the
Determination of Organic Compounds in Drinking Water. EPA-600/4-88-039
December 1988, Revised, July 1991. Methods 506, 547, 550, 550.1 and 551 are
in Methods for the Determination of Organic Compounds in Drinking Water -
Supplement I. EPA/600-4-90/020, July 1990. Methods 515.2, 524.2, 548.1,
549.1, 552.1 and 555 are in Methods for the Determination of Organic Compounds
in Drinking Water - Supplement II. EPA/600/R-92/129, August 1992. Method 1613
is titled, "Tetra-Through Octa-Chlorinated Dioxins and Furans by Isotope
Dilution HRGC/HRMS," EPA 821-B-94-005, October 1994. These documents are
available from the National Technical Information Service, (NTIS) PB91-231480,
PB91-146027, PB92-207703 and PB95-104774, U.S. Department of Commerce, 5285
Port Royal Road, Springfield, Virginia 22161. The toll-free number is
800-553-6847. EPA Methods 504.1, 508.1 and 525.2 are available from USEPA
EMSL-Cincinnati, Cincinnati, OH 45268. The phone number is (513J-569-7586.
Method 6651 is contained in the 18th edition of Standard Methods for the
Examination of Water and Wastewater. 1992, and Method 6610 is contained in the
Supplement to the 18th edition of Standard Methods for the Examination of
Water and Wastewater, 1994, American Public Health Association, 1015 Fifteenth
Street NW, Washington, D.C. 20005.
-------
METHODS FOR UNREGULATED CONTAMINANTS
Regulations specified in §141.40 require monitoring for certain
contaminants to which maximum contaminant levels do not apply. These
chemicals are called "unregulated" contaminants, and presently include
sulfate, 34 volatile organic chemicals (VOCs) and 13 synthetic organic
chemicals (SOCs).
1.
Analysis for the 34 unregulated VOCs listed under paragraphs (e) and
(j) of §141.40 shall be conducted using the following recommended
methods, or their equivalent as determined by EPA.
VOC Contaminants
Chloroform
Bromodi chloromethane
Bromoform
Chlorodi bromomethane
Bromobenzene
Bromochloromethane
Bromomethane
n-Butylbenzene
sec-Butyl benzene
tert-Butylbenzene
Chloroethane
Chloromethane
o-Chlorotoluene
p-Chlorotoluene
Dibromomethane
m-Di chlorobenzene
Dichlorodifluoromethane
1,
1,
2,
1,
1-Dichloroethane
3-Dichloropropane
2-Di chloropropane
1-Dichloropropene
1,3-Di chloropropene
Fluorotri chloromethane
Hexachlorobutadi ene
Isopropylbenzene
p-Isopropyltoluene
Naphthalene
n-Propylbenzene
1,1,2,2-Tetrachloroethane
1,1,1,2-Tetrachloroethane
1,2,3-Tri chlorobenzene
1,2,3-Tri chloropropane
1,2,4-Trimethylbenzene
1,3,5-Tri methyl benzene
Method
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
502.2,
524.2, 551
524.2, 551
524.2, 551
524.2, 551
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2
524.2, 504.1
524.2
524.2
10
-------
METHODS FOR UNREGULATED CONTAMINANTS (CONT.)
2.
Analysis for the 13 unregulated SOCs listed under paragraph (n)(ll)
of §141.40 shall be conducted using the following recommended
methods. ,
SOC Contaminants
Aldicarb
Aldicarb sulfone
Aldicarb sulfoxide
Aldrin
Butachlor
Carbaryl
Dicamba
Dieldrin
3-Hydroxycarbofuran
Methomyl
Metolachlor
Metribuzin
Propachlor
Method !
531.1, 6610 '
531.1, 6610
531.1, 6610 i
505, 508, 525.2, 508.1
507, 525.2
531.1, 6610
515.1, 515.2, 555
505, 508, 525.2, 508.1
531.1, 6610
531.1, 6610
507, 525.2, 508.1
507, 525.2, 508.1
508, 525.2, 508.1
Other mandatory and optional procedures for conducting analyses of
unregulated VOCs and SOCs are described in Sections IV and V, respectively of
this Technical Notes document. Sources for EPA Methods 502.2 504 1 505 '
507 508, 508.1, 515.1, 515.2, 524.2, 525.2, 531.1 and 551 and Standard Method
6610 are referenced above under methods for organic chemicals.
3. Analysis for the unregulated inorganic contaminant listed under
paragraph (n)(12) of §141.40 shall be conducted using the following
recommended methods.
Contaminant
Sulf ate
Analytical'Method1
EPA ASTM SM
300.0
375.2
D4327-91
D516-90
4110
4500-SO,-F
4500-S04-E
1.
Sources for the Standard Methods and ASTM sulfate methods are referenced
above under methods for inorganic chemicals. The EPA methods are contained
in Methods for the Determination of Inorganic Substances in Environmental
Samples," EPA/600/R-93/100, August 1993, which is available at NTIS, PB94-
121811. •
11
-------
METHODS FOR FILTRATION AND DISINFECTION
1. Microbiological. oH. and Turbidity Methods
To comply with provisions of the Surface Water Treatment Rule monitoring
under Subpart H of 40 CFR Part 141, public water systems must conduct analyses
of total coliforms, fecal coliforms, heterotrophic bacteria, turbidity, and
temperature in accordance with one of the following analytical methods, and by
using mandatory procedures for turbidimeter calibration, which are specified
in Section IV of this Technical Notes document. Approved methods for pH are
described above under "Methods for Inorganic Contaminants."
Organism Methodology Citation1
Total Coliforms2
Fecal Coliforms2
Heterotrophic
bacteria
Turbidity
Total Col i form Fermentation
Technique3'4'5
Total Coli form Membrane Filter
Technique
ONPG-MUG Test6
Fecal Coli form MPN Procedure7
Fecal Coli form Membrane Filter
Procedure
Pour Plate Method
Nephelometric Method
Nephelometric Method
Great Lakes Instruments
9221A, B, C
9222A, B, C
9223
9221E
9222D
9215B
2130B
180. I8
Method 29
2550
Footnotes
1 Except where noted, all methods refer to the 18th edition of Standard
Methods for the Examination of water and Wastewater. 1992, American Public
Health Association, 1015 Fifteenth Street NW, Washington, D.C. 20005.
2 The time from sample collection to initiation of analysis may not exceed 8
3°Lactose broth, as commercially available, may be used in lieu of lauryl
tryptose broth, if the system conducts at least 25 parallel tests between this
medium and lauryl tryptose broth using the water normally tested, and this
comparison demonstrates that the false-positive rate for total coliforms,
using lactose broth, is less than 10%.
4 Media should cover inverted tubes at least one-half to two-thirds after the
sample is added.
5 No requirement exists to run the completed phase on 10 percent of all total
coliform-positive confirmed tubes.
6 The ONPG-MUG Test is also known as the Autoanalysis Colilert System.
12
-------
7 A-l Broth may be held up to 3 months in a tightly closed screwcap tube at
H o • -
8 "Methods for the Determination of Inorganic Substances in Environmental
Samples," EPA-600/R-93-100, August 1993. Available at NTIS, PB94-121811
oo«IMMeitp«2L "Turbidity>" November 2, 1992, Great Lakes Instruments, Inc.,
8855 North 55th Street, Milwaukee, Wisconsin 53223.
2. Disinfectant Residual Methods
Public water systems must measure residual disinfectant concentrations
with one of the analytical methods in the following table. The methods are
contained in the 18th edition of Standard Methods. Corrections to SM-4500-C1-
E and 4500-C1-G, and procedures for conducting continuous measurements of
chlorine residuals are described in the Technical Notes in Section IV of this
document.
Residual
Methodology
Free Chlorine2
Total Chlorine2
Chlorine Dioxide
Ozone
Amperometric Titration
DPD Ferrous Titrimetric
DPD Colorimetric
Syringaldazine (FACTS)
Amperometric Titration
Amperometric Titration
(low level measurement)
DPD Ferrous Titrimetric
DPD Colorimetric
lodometric Electrode
Amperometric Titration
DPD Method
Amperometric Titration
Indigo Method
4500-C1 D
4500-C1 F
4500-C1 G
4500-C1 H
4500-C1 D
4500-C1 E
4500-C1 F
4500-C1 G
4500-C1 I
4500-C10, C
4500-C102 D
4500-C102 E
4500-0^ B
Footnotes
If approved by the State, residual disinfectant concentrations for free
chlorine and combined chlorine also may be measured by using DPD Colorimetric
test kits. [
Free and total chlorine residuals may be measured continuously by adaptinq
a specified chlorine residual method for use with a continuous monitoring
instrument provided the chemistry, accuracy, and precision of the measurement
remain same. Instruments used for continuous monitoring must be calibrated
with a grab sample measurement at least every 5 days, or with a protocol
approved by the State.
13
-------
SECTION II. METHODS TO BE WITHDRAWN ON JULY 1, 1996
For convenience and clarity, the methods to be withdrawn on July 1, 1996
are specified in this document in lieu of listing them in the drinking water
regulations at 40 CFR Part 141. The following methods may be used to obtain
certification and to analyze drinking water compliance samples until July 1,
1996. However, if the rule, which promulgates this withdrawal action, is
published after January 1, 1995, the withdrawal date becomes 18 months after
publication of the final rule in the Federal Register.
ANALYTICAL METHODS TO BE WITHDRAWN FOR INORGANIC CONTAMINANTS
In addition to methods cited at §141.23(k)(l), the methods in the
following table only are approved until July 1, 1996 for analyses for
antimony, arsenic, barium, beryllium, cadmium, cyanide, fluoride, mercury,
nickel, nitrate, nitrite, selenium, sodium and thallium. These methods were
previously specified at §141.23(k)(l), except arsenic, fluoride and sodium,
which were previously specified at §141.23(k)(2), §141.23(k)(3) and
§141.41(c), respectively.
Contaminant Methodology
Antimony4 Atomic Absorption; Furnace
Arsenic4 Atomic Absorption; Furnace
Hydride-Atomic Absorption
Spectrophotometri c
Barium4 Atomic Absorption; Direct
Atomic Absorption; Furnace
EPA1
204.2
206.2
206.3
206.4
208.1
208.2
ASTM2 SM3
D-2972-88A 307B
Beryllium4 Atomic Absorption; Furnace
Cadmium4 Atomic Absorption; Furnace
Chromium4 Atomic Absorption; Furnace
210.2
213.2
218.25
Cyanide Manual Distillation
followed by
Spectrophotometri c
. Manual
Amenable, Spectrophotometric
Fluoride Manual Distill.; Color. SPADNS
Manual Electrode
Automated Alizarin
14
335.2e
335.1
340.1
340.2
340.3
-------
Mercury4 Manual, Cold Vapor
245.1
Nickel4
Nitrate
Nitrite
Selenium4
Thallium4
Sodium
Atomic Absorption; Direct
Atomic Absorption; Furnace
Manual Cadmium Reduction
Automated Hydrazine Reduction
Manual Cadmium Reduction
Spectrophotometric
Atomic Absorption; Furnace
Atomic Absorption; Furnace
Atomic Absorption; Direct
Atomic Absorption; Furnace
Flame Photometric
249.1
249.2
353.3
353.1
353.3
354.1
270.25'7
279.2
273.1
273.2
D1428-64a 320A
Footnotes
1
"Methods for Chemical Analysis of Water and Wastes," EPA-6QO/4-79-020, March
1983. Available at NTIS, publication order number PB84-128677.
Annual Book of ASTM Standards. Part 31, American Society ifor Testing and
Materials, 1916 Race Street, Philadelphia, PA 19103. j
Methods 320A and 307B are contained in the 14th (1975) and 16th (1985) editions,
respectively, of Standard Methods for the Examination of Water and Wastewater
American Public Health Association, 1015 Fifteenth Street, Washington, D.C.
20005.
Several spectrochemical techniques are approved for the determination of metal
and metalloid contaminants in drinking water. These techniques are: inductively
coupled plasma-atomic emission spectrometry; inductively coupled plasma-mass
spectrometry; direct aspiration flame, graphite furnace, and platform graphite
furnace atomic absorption spectrometry. To conduct these measurements, samples
must not be filtered prior to either sample digestion or "direct analysis."
Samples are acid preserved with nitric acid to pH less than 2, held for 16
hours, and the pH verified to be less than 2 before sample processing is
started. In addition, the turbidity of the acidified sample must be measured
with an approved method, and after preservation is complete. If turbidity is
greater than 1 nephelometric turbidity unit (NTU), sample digestion is required
using the digestion procedure described in the approved method (except the
perchloric acid digestion in SM 3114B must not be used). If the acid preserved
sample contains turbidity less than 1 NTU, the sample may be analyzed by "direct
analysis" without digestion. However, irrespective of the turbidity of the
sample, when determining mercury by cold vapor atomic absorption (CVAA), or
antimony, arsenic, or selenium (Sb, As, and Se) by gaseous hydride atomic
absorption, sample aliquots must be digested prior to analysis. Digestion is
necessary, because organomercury compounds that may be present in drinking water
and performance samples cannot be analyzed by CVAA unless converted to inorganic
15
-------
mercury, and because Sb, As, and Se each must be converted to a specific valence
state prior to reduction and generation of the hydride for analysis.
For the determination of chromium by graphite furnace analysis, an appropriate
volume of 30% hydrogen peroxide (1-mL of 30% H202 per 100 ml of sample or
standard) should be added to the calibration standards and the sample prior to
analysis. The addition of hydrogen peroxide ensures that chromium in the sample
and calibration standards is in the same valence state [Cr(III)]. This provides
uniform signal response in conventional off-the-wall graphite furnace
determinations of chromium. Also, calcium concentrations ranging from 10 to 50
mg/L have demonstrated a nonuniform suppressive (less than 20%) matrix effect in
conventional off-the-wall nonpyrolytic graphite furnace determinations of
chromium. If calcium is present at these concentrations in the chromium sample,
use of the matrix modifier magnesium nitrate is highly recommended (cf. SM
3113A).
The distillation procedure in EPA Method 335.2 should not be usec), and the
sodium hydroxide absorber solution final concentration must be adjusted to 0.25
N before colorimetric analysis.
For graphite furnace determinations of selenium when nickel nitrate is used as
the matrix modifier, an appropriate volume of 30% hydrogen peroxide (2-mL 30%
H202 per'100 ml of sample or standard) should be added to both the calibration
standards and samples prior to analysis. It has been demonstrated that the
addition of hydrogen peroxide enhances the absorption signal response in
conventional off-the-wall graphite furnace determinations of selenium. If
digestion of the sample is required, because sample turbidity is greater than 1
NTU, hydrogen peroxide is added to the sample at the time of digestion. Nickel
nitrate (Ni cone, of 0.1%) either is added to an aliquot of the processed sample
and calibration standards at the time of analysis or may be added directly in
the furnace (20 #g Ni per 20 /*L injection).
16
-------
ANALYTICAL METHODS TO BE WITHDRAWN FOR LEAD, COPPER, AND CORROSIVITY
In addition to the methods cited at §141.23(k)(l), the methods in the
following table are approved until July 1, 1996 for analyses for lead, copper,
conductivity, calcium, alkalinity, orthophosphate and silica. These methods
were previously specified on June 30, 1994 (59 FR 33863) at §141.89(a).
Contaminant
Lead2
Copper2
Atomic
Atomic
Atomic
Methodology
absorption;
absorption;
absorption;
furnace
furnace
direct
technique
technique
aspiration
EPA
239
220
220
1
.2
.2
• 1 -
Conductivity
Calcium2
Alkalinity
Orthophosphate
(unfiltered,
no digestion
or hydrolysis)
Silica
Conductance 120.1
EDTA titrimetric 215.2
Atomic absorption; direct aspiration 215.1
Titrimetric 310.1
Colorimetric, ascorbic acid, two 365.3
reagent
Colorimetric, ascorbic acid, single 365.2
Colorimetric 370.1
Footnotes i ' ,.
1 "Methods for Chemical Analysis of Water and Wastes," EPA-600/4-79-020,
March 1983. Available at NTIS as PB84-128677.
2 To conduct these measurements samples must not be filtered prior to either '
sample digestion or "direct analysis," Samples are acid preserved with nitric
acid to pH less than 2, held for 16 hours, and the pH verified to be less than
2 before sample processing is started. In addition, the turbidity of the
acidified sample must be measured using an approved method, and after acid
preservation is complete. If turbidity is greater than 1 nephelometric
turbidity unit (NTU), sample digestion is required using the digestion
procedure described in the approved method. If the acid preserved sample
contains turbidity less than 1 NTU, the sample may be analyzed by "direct
analysis" without digestion. When digestion is required, the total
recoverable technique as defined in the method must be used.
17
-------
ANALYTICAL METHODS TO BE WITHDRAWN FOR ORGANIC CONTAMINANTS
In addition to methods cited at §141.24(e), the methods specified in the
following table may be used until July 1, 1996 for analysis of the
contaminants specified below. Methods 502.1, 503.1 and 524.1 are contained in
Methods for the Determination of Organic Compounds in Drinking Hater.
EPA/600/4-88/039, December 1988, Revised, July 1991, which is available from
the National Technical Information Service (NTIS), PB91-231480, U.S.
Department of Commerce, 5285 Port Royal Road, Springfield, Virginia 22161.
The phone number is 800-553-6847. Methods 501.1 and 501.2 for analysis of
total trihalomethanes in accordance with the monitoring requirements specified
at §141.30 will be printed at 40 CFR 141.30, Appendix C until July 1, 1995.
Contaminant EPA Method
Benzene 503.1, 524.1
Carbon tetrachloride 502.1, 524.1
Chlorobenzene 502.1, 503.1, 524.1
1,2-Dichlorobenzene 502.2, 524.1
1,4-DiChlorobenzene 502.1, 503.1, 524.1
1,2-Dichloroethane 502.1, 524.1
cis-Dichloroethylene 502.1, 524.1
trans-Dichloroethylene 502.1, 524.1
Dichloromethane 502.1, 524.1
1,2-Dichloropropane 502.1, 524.1
Ethyl benzene 503.1, 524.1
Styrene 503.1, 524.1
Tetrachloroethylene 502.1, 503.1, 524.1
1,1,1-Trichloroethane 502.1, 524.1
Trichloroethylene 502.1, 503.1, 524.1
Toluene 503.1, 524.1
1,2,4-TriChlorobenzene 503.1
1,1-Dichloroethylene 502.1, 524.1
1,1,2-Trichloroethane 502.1, 524.1
Vinyl chloride 502.1, 524.1
Xylenes (total) 503.1, 524.1
Total Trihalomethanes 501.1, 501.2
ANALYTICAL METHODS TO BE WITHDRAWN FOR UNREGULATED VOCS
In addition to methods cited at §141.40(g), EPA Methods 502.1, 503.1 and
524.1 may be used until July 1, 1996 for analysis of the unregulated VOC
contaminants that are listed in §141.40(e) and (j)> if the contaminant is
listed in the analytical scope of the method. These VOC methods are contained
in the EPA manual described above for organic contaminants.
18
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METHOD TO BE WITHDRAWN FOR FILTRATION AND DISINFECTION
In addition to methods cited at §141.74(a)(5), Standard Method 408F
(Leuco Crystal Violet) may only be used until July 1, 1996 for analysis of
free chlorine and combined chlorine (chloramines). This method is contained
in the 16th edition of Standard Methods for the Examination of Water and
Wastewater. 1985, American Public Health Association, 1015 Fifteenth Street
NW, Washington, D.C. 20005.
19
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SECTION III. RECOMMENDED METHODS FOR SECONDARY DRINKING WATER CONTAMINANTS
Analyses of aluminum, chloride, copper, fluoride, foaming agents, iron,
manganese, odor, silver, sulfate, total dissolved solids (TDS) and zinc to
determine compliance under §143.3 may be conducted with the methods in the
following Table. Criteria for analyzing aluminum, copper, iron, manganese,
silver, and zinc samples with digestion or directly without digestion, and
other mandatory procedures are contained in the Technical Notes in Section IV
of this document. Measurement of pH may be conducted with one of the methods
listed above in Section I under "Methods for Inorganic Chemicals."
Contaminant
Aluminum
Chloride
Color
Copper
Fluoride
Foaming Agents
Iron
Manganese
Odor
Silver
Sulfate
EPA
200.73
200.83
200.93
300.0*
200. r
200.83
200.93
300.O4
200. T
200.93
200. T
200.83
200.93
200.73
200.83
200.93
300.O4
375.24
ASTM1
D4327-91
D1688-90A
D1688-90C
D4327-91
D1179-93A
D1179-93B
D4327-91
SM2
3120B
3113B
3111D
4110
4500-CT-D
2120B
3120B
3111B
3113B
4110
4500F-B,D
4500F-C
4500F-E
5540C
3120B
3111B
3113B
3120B
3111B
3113B
2150B
3120B
3111B
3113B
4110
4500-S04-F
4500-S04-C,D
Other
129-71W5
380-75WE5
I-3720-856
20
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Contaminant
IDS
Zinc
EPA
200.7'
200.83
ASTM1
Other
2540C
3120B
3111B
Footnotes
1 Annual Book of ASTM Standards. Vols. 11.01 and 11.02, American Society for
Testing and Materials, 1916 Race Street, Philadelphia, PA 19103.
18th edition of Standard Methods for the Examination of Water and
Wastewater, 1992, American Public Health Association, 1015 Fifteenth Street
NW, Washington, D.C. 20005.
"Methods for the Determination of Metals in Environmental Samples -
Supplement I," EPA-600/R-94-111, May 1994. Available at MTIS, PB94-184942.
"Methods for the Determination of Inorganic Substances in Environmental
Samples," EPA-600/R-93-100, August 1993. Available at NTIS, PB94-121811.
Industrial Method No. 129-71W, "Fluoride in Water and Wastewater," December
1972, and Method No. 380-75WE, "Fluoride in Water and Wastewater," February
1976, Technicon Industrial Systems, Tarrytown, NY 10591. ;
Available from Books and Open-File Reports Section, U.S.i Geological Survey
Federal Center, Box 25425, Denver, CO 80225-0425.
21
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SECTION IV. MANDATORY METHOD MODIFICATIONS
I
This section contains several mandatory method modifications in a series
of Technical Notes. Each Technical Note is on a separate sheet to allow users
to remove it, and place it with the applicable compliance method(s). The
parenthetical number (R), which appears adjacent to method citations in this
section, refers to the publication in Section VI (References) that contains
the referenced method.
Tech. Notes on DW Methods
October 1994 - Section IV
22 Mandatory Method Modifications
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STANDARD METHOD (SM) 4500-C1-E (R12), CHLORINE RESIDUALS
This Technical Note corrects a typographical error in SM 4500-C1-E, "Low
Level Amperometric Titration" (R12). This method is currently approved at
§141.74(a) for measurement of chlorine residuals. When the method is
republished, the Standard Methods Committee will correct an error1 in the
numerical factor in the denominator of the formula in part 5 of the method.
The formula is on page 4*-43 of the 18th edition of Standard Methods. The
correct formula must have a factor of 0.00564, which is 10 times greater than
the factor printed in the incorrect formula.
Letter from Andrew D.. Eaton, "Error in 4500-C1 E," June 4,1993,
American Public Health Association, 1015 Fifteenth Street NW, Washington,
D.C. 20005.
Tech. Notes on DM Methods
October 1994 - Section IV
23 Mandatory Method Modifications
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STANDARD METHOD (SM) 4500-C1-G (R12), CHLORINE RESIDUALS
This Technical Note recognizes and corrects an error in SM 4500-C1-6
(R12). This DPD method is currently approved at §141.74(a) for measurement of
chlorine residuals. The method as published omits instructions that would
allow measurement of total residual chlorine in drinking water samples. The
Standard Methods Committee has determined1 that an editorial omission, not a
technical change, occurred in recent versions of this method. The error will
be corrected in the next (19th) edition of Standard Methods.
The simplified procedure, which uses DPD chemistry, was omitted from SM
4500-C1-G (18th ed., para. 4, p. 4-46). EPA corrects the Standard Method
error, by printing a correction to paragraph four below. The correction also
applies to the 16th edition version of this method, SM 408E.
Simplified Procedure for Total Chlorine
"To obtain monochloramine and dichloramine together las combined chlorine
omit step 4d in SM 4500-C1-G (monochloramine determination). To obtain
total chlorine in one reading add the full amount of potassium iodide at
the start with the specified amounts of buffer reagent and DPD indicator.
Read color after 2 minutes." :
Letter from Andrew D. Eaton, "Inquiry on Chlorine Residual
4500-C1 (18th Edition)," October 26, 1993, American Public Health
Association, 1015 Fifteenth Street NW, Washington, D.C. 20005.
Tech. Notes on DW Methods
October 1994 - Section IV
24 Mandatory Method Modifications
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PROTOCOL FOR CONTINUOUS CHLORINE RESIDUAL MONITORING
In this Technical Note EPA provides specifications for continuous
monitoring of chlorine residuals. These instructions were inadvertently
omitted from the Surface Water Treatment Rule (54 FR 27486, June 29, 1989).
EPA will permit a grab sample method, which is approved for chlorine residual
monitoring at §141.74(a), to be adapted for continuous monitoring of free or
total chlorine residuals provided the chemistry, accuracy, and precision of
the method are unchanged. Instruments used for continuous monitoring must be
calibrated with a grab sample measurement at least every 5 clays, or with a
protocol approved by the State. If the State also approves, calibration may
include minor changes in the reagent mix provided the overall chemistry of the
method is not changed. Approved grab sampling methods for chlorine residual
measurement are listed below.
Residual
Methodology
Methods
Free Chlorine
Total Chlorine
Amperometric Titration
DPD Ferrous Titrimetric
DPD Colorimetric
Syringaldazine (FACTS)
Amperometric Titration
Amperometric Titration
(low level measurement)
DPD Ferrous Titrimetric
DPD Colorimetric
lodometric Electrode
4500-C1 D
4500-C1 F
4500-C1 G
4500-C1 H
4500-C1 D
4500-C1 E
4500-C1 F
4500-C1 6
4500-C1 I
If approved by the State, residual disinfectant concentrations for free
chlorine and combined chlorine also may be measured by using DPD Colorimetric
test kits.
25
Tech. Notes on DW Methods
October 1994 - Section IV
Mandatory Method Modifications
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SPECTROPHOTOMETRIC DETERMINATIONS OF CYANIDE
Mandatory Manual Distillation in Cvani'de Methods
In this Technical Note EPA emphasizes that spectrophotometric
measurements of cyanide in water samples always require a manual digestion of
the sample to prepare the sample for measurement of cyanide. EPA believes
emphasis is needed, because some laboratories seem to be unaware of this
requirement. All approved spectrophotometric methods for cyanide are
specified at 40 CFR 141.23(k)(l) under the phrase, "Manual distillation
followed by." Standard Method SM-4500-CN-C (R12), which describes the
mandatory manual distillation procedure, is cited in the rules immediately
after this phrase.
"Amenable" spectrophotometric methods also require distillation prior to
either free or total cyanide measurements. The approved amenable, manual and
automated spectrophotometric methods for cyanide are ASTM D2036-91B and D2036-
91A (Rll); SM 4500-CN-F and 4500-CN-G (R12); EPA Methods 335.1, 335 2 and
335.3 (R14), EPA 335.4 (R4); and USGS 1-3300-85 (R19). (Note: EPA Methods
335.1 and 335.2 will be withdrawn on July 1, 1996, and Method 335.3 has been
replaced by Method 335.4).
To avoid manual distillation, laboratories can use a selective electrode
method for cyanide, which is discussed below.
Selective Electrode Method. SM 4500-CN-F (R12^
EPA regulates free, not total, cyanide. If SM 4500-CN-F is used to
determine free cyanide, distillation is not required. However, to maintain a
constant Tonic strength background for the electrode measurement, samples and
standards must contain the same concentration of sodium hydroxide.
Reduced Volume Cvanide Distillation ,
In 1994 EPA Method 335.3 was replaced with Method 335J4. The technical
differences between the methods are minor; both methods require manual
distillation of the sample. However, EPA improved the automation of
procedures in Method 335.4, and added an optional, reduced volume distillation
procedure. Method 335.4 does not contain the discussion in Method 335.3 of an
alternate ultraviolet (UV) digestion procedure, because EPA never approved
this optional UV procedure, and because EPA believes that UV digestion will
underestimate cyanide concentrations in the drinking water ;sample.
Tech. Motes on DW Methods
October 1994 - Section IV
26 Mandatory Method Modifications
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-------
In this Technical Note, EPA is approving reduced volume distillation for
all spectrophotometric cyanide methods. Criteria for reduced volume
distillation are as follows. !
"Reduction in digestion or distillation volumes is acceptable provided
all sample-to-reagent ratios are maintained, and provided the final
sample volume is sufficient for instrumental measurement of cyanide.
Reduced volume distillation apparatus, when employed as described, can be
considered an acceptable minor modification to approved cyanide
methodology."
EPA Method 335.2 (R14)
This method will be withdrawn on July 1, 1996. This Technical Note
amends Method 335.2 as follows. The sodium hydroxide absorber solution final
concentration must be adjusted to 0.25 N before colorimetnc analysis The
distillation procedure that is described in the method should not be used
because it uses a secondary scrubber that does not work well.
Tech. Notes on DW Methods
October 1994 - Section IV
27 Mandatory Method Modifications
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TURBIDIMETER CALIBRATION (R4, R9, R12)
EPA Method 180.1 (R4), SM 2130B (R12) and 6LI Method 2 (R9) are approved
at §141.74(a) for measurement of turbidity. This Technical Note specifies
that calibration of the turbidimeter must be made either by the use of a
formazin standard as specified in the approved method or with a styrene
divinyl benzene polymer standard (Amco AEPA-1 Polymer). This reagent is
commercially available from Advance Polymer Systems, Inc., 3696 Haven Avenue,
Redwood City, California 94063.
Tech. Notes on DM Methods
October 1994 - Section IV
28 Mandatory Method Modifications
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SAMPLE DIGESTION FOR DETERMINATION OF METAL CONTAMINANTS j
This Technical Note describes when and how a sample must be digested for
accurate compliance measurements of metals in drinking water samples. Several
spectrochemical techniques are approved for the determination of metal and
metalloid contaminants in drinking water. These techniques are: inductively
coupled plasma-atomic emission spectrometry; inductively coupled plasma-mass
spectrometry; direct aspiration flame, graphite furnace, and platform graphite
furnace atomic absorption spectrometry. To conduct these measurements,
samples must not be filtered prior to either sample digestion or "direct
analysis." Samples are acid preserved with nitric acid to pH less than 2.
Preservation is complete after the acidified sample has been held for 16
hours. Before sample processing is started, sample pH must be verified to be
less than 2.
To determine whether digestion of the sample is required, the turbidity
of the acidified sample must be measured using an approved method and only
after preservation is complete. If turbidity is greater than 1 nephelometric
turbidity unit (NTU), sample digestion is required using the digestion
procedure described in the approved method (see exception below for SM 3114B).
If the acid preserved sample contains turbidity less than 1 NTU, the sample
may be analyzed by "direct analysis" without digestion. i
However, irrespective of the turbidity of the sample,: when determining
mercury by cold vapor atomic absorption (CVAA), or antimony (Sb), arsenic (As)
or selenium (Se) by gaseous hydride atomic absorption, sample aliquots must be
digested prior to analysis. Digestion of the sample, which is described in
the applicable method , is necessary, because organomercury compounds that may
be present in drinking water and performance samples cannot be analyzed by
CVAA unless converted to inorganic mercury, and because Sb, As, and Se each
must be converted to a specific valence state prior to reduction and
generation of the hydride for analysis. :
SM 3114B Exception - When determining arsenic or selenium using gaseous
hydride SM 3114B (R12), the perchloric acid digestion should never be used.
See the Technical Note on "SM 3114B, Arsenic and Selenium" for additional
instructions and explanations.
Tech. Notes on DW Methods
October 1994 - Section IV
29 Mandatory Method Modifications
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STANDARD METHOD 3114B (R12), ARSENIC AND SELENIUM
This Technical Note describes an important safety warning when using
sample digestion procedures that are described in SM 3114B (R12).
Determination of arsenic and selenium by gaseous hydride atomic absorption
requires digestion of the sample prior to analysis. SM 3114B describes two
digestion procedures. One procedure, referred to as the "total recoverable"
preparation, uses perchloric acid in the final stage of digestion. This
perchloric acid digestion procedure is not required by EPA, and should be
avoided, because of potential danger when using perchloric acid, and because a
special fume hood is required. When using method SM 3114B, the digestion
procedure described in paragraph 4.d, Preparation of samples and standards for
total arsenic and selenium, that specifies the use sulfuric acid and potassium
persulfate should be utilized. This warning is not applicable to the ASTM
gaseous hydride methods for arsenic and selenium, because the methods do not
allow use of perchloric acid digestion.
Tech. Motes on DW Methods
October 1994 - Section IV
30 Mandatory Method Modifications
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ASTM D3859-93B (Rll) AND STANDARD METHOD 3113B (R12), SELENIUM
This Technical Note concerns graphite furnace determinations of selenium
with ASTM D3859-93B (Rll) or SM 3113B (R12). When nickel nitrate is used as
the matrix modifier, an appropriate volume of 30% hydrogen peroxide (2-mL 30%
H202 per 100 ml of sample or standard) should be added to both the calibration
standards and samples prior to analysis. It has been demonstrated that the
addition of hydrogen peroxide enhances the absorption signal response in
conventional off-the-wall graphite furnace determinations of selenium.. If
digestion of the sample is required, because sample turbidity is greater than
1 NTU, hydrogen peroxide is added to the sample at the time of digestion
Nickel nitrate (Ni cone, of 0.1%) either is added to an aliquot of the
processed sample and calibration standards at the time of analysis or may be
added directly in the furnace (20 #g Ni per 20 pi injection).
Tech. Notes on DW Methods
October 1994 - Section IV
31 Mandatory Method Modifications
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STANDARD METHOD 3113B (R12), CHROMIUM
This Technical Note describes procedures for correctly conducting a
graphite furnace determination of chromium in a drinking water sample using SM
3113B (R12). The method requires that an appropriate volume of 30% hydrogen
peroxide (1-mL of 30% H20p per 100 ml of sample or standard) be added to the
calibration standards ana the sample prior to analysis. The addition of
hydrogen peroxide ensures that chromium in the sample and calibration
standards is in the same valence state, chromium [III]. This provides uniform
signal response in conventional off-the-wall graphite furnace determinations
of chromium.
Calcium concentrations ranging from 10 to 50 mg/L have demonstrated a
nonuniform suppressive (less than 20%) matrix effect in conventional off-the-
wall nonpyrolytic graphite furnace determinations of chromium. If calcium is
present at these concentrations in the chromium sample, use of the matrix
modifier magnesium nitrate is highly recommended (cf. SM 3113A).
Tech. Notes on DW Methods
October 1994 - Section IV
32 Mandatory Method Modifications
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METHODS 502.2 (R16) AND 524.2 (R3), SORBENT TRAPS
This Technical Note describes under what conditions an alternate trap may
be used in EPA Methods 502.2, Rev. 2.0 (R16) and 524.2, Rev. 4.0 (R3). Both
methods allow use of alternative sorbents to trap volatile organic compounds,
provided all quality assurance criteria specified in the method are met. This
option is already included in Method 524.2 in Sect. 6.2.2, but an explicit
requirement not to change other method conditions is missing. EPA notes that
some alternate traps may not work under Method 502.2 or 524.2 conditions,
because the purge and desorption procedures specified in the methods are
optimized for the trap media specified in the methods. These procedures may
not be changed. Specifically, the purge time, purge gas flow rate, and the
desorption time specified in the method may not be changed, because EPA has no
data to show that reliable or reproducible results can be obtained if purging
or desorption times or flows differ from the specified limits.
The purging and desorption conditions for these methods were designed to
achieve analytical maximum efficiency. The purge time and purge gas flow rate
required to efficiently purge the target analytes from the water sample are
largely independent of the sorbent trapping material. Decreasing the purging
or desorption times or gas flows will decrease purging efficiency and/or
recovery of target analytes, which will have a negative impact on method
precision. Since many of the potential alternate sorbents may be thermally
stable at temperatures higher than 180°C, alternate traps may be desorbed and
baked out at higher temperatures than those described in the current method
revisions. If higher temperatures are used, the analyst should monitor the
data for analyte and trap decomposition.
This Technical Note amends Method 502.2, Rev. 2.0 by adding the following
sentence to the end of Sect. 6.2.2.
"The use of alternative sorbents is acceptable provided the data acquired
meets all quality control criteria described in Section 10, and provided
the purge and desorption procedures specified in Section 11 of the method
are not changed."
Method 524.2, Rev. 4.0 is amended by changing the last sentence in Sect.
6.2.2 to read as follows.
"The use of alternative sorbents is acceptable provided the data acquired
meets all quality control criteria described in Section 9, and provided
the purge and desorption procedures specified in Section 11 of the method
are not changed."
Tech. Notes on DW Methods
October 1994 - Section IV
33 Mandatory Method Modifications
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EPA METHODS 502.2, REV. 2.0 (R16), 524.2, REV. 4.0 (R3), AND 551 (R15) IN
SAMPLE ACIDIFICATION
This Technical Note clarifies that samples must be acidified at the time
of collection, but after they have been dechlorinated. Acidification must not
be delayed until the samples are received in the laboratory. These
instructions supersede instructions implied or explicit that may be contained
in the methods.
Tech. Notes on DW Methods
October 1994 - Section IV
34 Mandatory Method Modifications
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METHOD 506 (R15), ERRATA IN SUMMARY
Ma*fc«JhJnCT?S?]Cal !I0te fleets minor Qrrors in the introductory sections of
Method 506 (R15 , and emphasizes that clean sodium chloride is essential to an
accurate analysis. Method 506 is used to determine adipates and phthalates ?n
drinking water samples. The summary in Section 2 of Method 506 incorrectly
refers to use of a ternary solvent mixture to conduct the liquid-liquid
extraction of the sample; the correct procedure is methyl ene chloride followed
by hexane. .The method summary also omits a disk elution solvent. Section 2
is amended to correct these errors, and now reads in entirety as follows.
"A measured volume of sample, approximately 1-L, is extracted with
methyl ene chloride followed by hexane using a glass separator/ funnel
The solvent extract is isolated, dried and concentrated to a volume of 5
mi or less. The extract is further concentrated by using a gentle stream
of nitrogen gas to reduce the sample volume to 1 mL or less.
Alternatively, a measured volume of sample is extracted with a liquid-
solid extraction (LSE) cartridge or disk. The LSE media are eluted with
acetomtnle followed by methylene chloride (disk extraction) or with
methyl ene chloride only (cartridge extraction). The eluant is
concentrated using a gentle stream of nitrogen gas or clean air to reduce
the volume to 1 mL or less.
The analytes in the extract are separated by means of capillary gas
chromatography using temperature programming. The chromatographically
separated phthalate and adipate esters are measured with a
photoionization detector, which is operating at 10 eV."
arfrfo/I* ^rongly encourages laboratories to clean the sodium chloride that is
added to the sample by carefully following the heating and storage
instructions, which are described at Sect. 7.5 of the method. This will
reduce the background contamination measured in the laboratory reagent blank
samp I es .
Tech. Notes on DW Methods
October 1994 - Section IV
35 Mandatory Method Modifications
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METHOD 508 (R16), DCPA AND HEXACHLOROCYCLOPENTADIENE
This Technical Note approves Method 508, Rev. 3.0 (R]6) for compliance
measurement of hexachlorocyclopentadiene, provided the method performance
criteria specified in Section 9 of Method 508.1 (R6) are met. This Note also
th^rflcV mifsin9 entry in the table of analytes in Sect. 1.1 of Method 508;
the CAS Registry number for DCPA (dacthal) is 1861-32-1
Tech. Notes on DW Methods
October 1994 - Section IV
36 Mandatory Method Modifications
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METHODS 515.1 (R16) AND 515.2 (R3), USE OF TMSD
This Technical Note allows and describes use of trimethylsilyl-
diazomethane (TMSD) as an alternative derivatizing reagent in Methods 515.1,
Rev. 4.0 (R16) and 515.2, Rev. 1.0 (R3). EPA is approving TMSD, because some
laboratories prefer not to use the other approved derivatizing reagent,
Diazald. Since TMSD increases gas chromatographic background, the method
surrogate, 2,4-dichlorophenylacetic acid, cannot be used at concentrations of
1 0g/L or lower. Also, Diazald, not TMSD, must be used if dalapon is to be
determined, because dalapon is not amenable to esterification with TMSD. If
dalapon recovered from the drinking water sample is incompletely esterified,
dalapon concentrations will be underestimated. Laboratories wishing to avoid
use of Diazald may use Method 552.1 to determine dalapon, and Method 515.1 or
515.2 or 555 for the other chlorinated acid herbicides.
Steps, which replace or augment the calibration and extract
esterification (Sect. 11.4) method descriptions when TMSD is used, are
described below. The following procedure was written for Method 515.2, which
uses liquid-solid extraction (LSE). Analysts using TMSD with liquid-liquid
extraction (LLE) Method 515.1 should omit steps specific to LSE, and include
appropriate LLE steps from Method 515.1. In particular, the amounts of TMSD,
acetic acid, and internal standards to be added may have to be adjusted when
the TMSD procedure is adapted for use with Method 515.1. These adjustments
may be necessary, if the concentration ratio of original sample to final
extract is different in the two methods.
USE OF TRIMETHYLSILYLDIAZOMETHANE TO ESTERIFY
ACID HERBICIDES IN METHOD 515.21'2
1. INTRODUCTION
Trimethylsilyldiazomethane (TMSD) is available from a commercial supplier
(currently the Aldrich Chemical Company is the sole supplier) as a 2
molar solution in hexane. TMSD is stable during storage in this
solution. It should be noted that the gas chromatographic background is
somewhat increased when TMSD is used as the derivatizing reagent instead
of the generated diazomethane. Although no method analyte is affected by
this increased background, the recommended surrogate, 2,4-dichloro-
phenylacetic acid, is masked by an interfering peak. This renders the
surrogate useless at 1 /jg/L or lower. Any compound found suitable when
TMSD is used is acceptable as a surrogate.
Trimethylsilyldiazomethane can be used to efficiently methyl ate the
following acid herbicides:
37
Tech. Notes on DW Methods
October 1994 - Section IV
Mandatory Method Modifications
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Chemical CAS Registry Number
Acifluorofen 50594-66-6
Bentazon 25057-89-0
Chloramben 133-90-4
Dacthal 1861-32-1 ;
Dicamba 1918-00-9
Dichlorprop 120-36-5
Dinoseb 88-85-7
3,5-Dichlorobenzoic acid 51-36-5
2,4-D 94-75-7
2,4-DB 94-82-6
5-Hydroxydicamba 7600-50-2
Pentachlorophenol 87-86-5
Picloram 1918-02-1
2,4,5-TP (Silvex) 93-72-1
2,4,5-T 93-76-5
TMSD may not be used to esterify dalapon.
The following procedures to methyl ate the herbicides miist be followed.
2. CALIBRATION OF THE GAS CHROMATOGRAPH/ELECTRON CAPTURE DETECTION (GC/ECD)
O I O I trl 'i
Calibrate the GC/ECD system using fortified reagent water samples, and
use two sets of calibration solutions to prevent coelution. The presence
of coeluting analytes makes confirmation of positives mandatory before
taking action on a result. Follow the procedure described below using
TMSD to methylate the herbicides. Five concentration levels are
recommended. •
3. PROCEDURE
Carry out the hydrolysis, clean-up, and extraction of the method analytes
as described in Method 515.2 up to Sect. 11.2.4, or in Method 515.1 up to
Sect. 11.4. Users of Method 515.1 should begin below where the 2 M TMSD
solution is added.
Elute the herbicides from the disk by passing two 2 mL'aliquots of methyl
tertiary butyl ether (MTBE) through the disk into the collection tube.
Rinse the sample container with 4 mL of MTBE and pass it through the disk
into the tube.
Transfer the MTBE extract from the collection tube into an anhydrous
sodium sulfate drying tube which has been pre-wetted with 1 mL MTBE. Be
sure to discard any water layer.
Tech. Notes on DW Methods
October 1994 - Section IV
38 Mandatory Method Modifications
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-------
?XtraCJ E™r6S comPletely through the sodium sulfate, add an
2 ml of MTBE as a nnse.
Concentrate the dried extract to approximately 4 ml. Add methanol
(approx. 1 ml) to the extract to yield a 20% (v/v) methanol in MTBE
solution Adjust the volume to 5 ml with MTBE. (TMSD produces the most
efficient methylation of the herbicides in a 20% methanol , 80% MTBE
Add 50 nl of the 2 M TMSD solution to each 5 ml sample extract.
(Verify this volume if Method 515.1 is used.)
Allow the extract to cool to room temperature, then add 100
Method 515 Visaed?)1 ^ "^ ™* 6XCeSS ™SD' (Ver1fy
5°°C and
of 2 M
Volume if
e?tr;ct«wl^12?c'tL °f the interna1 standard solution (Method
0 OPoi,n' ;J 7;.2etJ^ 5 H' ^ect« 7'19> to ^ield a concentration of
0.020 fig/ml. (Verify this if Method 515.1 is used.)
Proceed with the identification and measurement of the analytes using
GC/ECD according to the procedures described in the method.
I ."Us.e °f Trimethylsilyldiazomethane as a Substitute Reagent for the
EsterifTcatTon of Phenoxy Herbicides," J. Collins and W.J. Bashe
CoSacHs fl '^P°ni'uInCp' iU]l 27' 1993 fPr°ject Performed under EPA
contract 68-C1- 0022, J.W. Eichelberger, Work Assignment Manager]
Amounts of TMSD, acetic acid, internal standards and other reagents
S^h JVtiK°ibe a5USted,.When the ™SD P™cedure is adapted for use with
Method 515. These adjustments will be necessary, if the concentration
th°d °nginal Sample to final extract is different in the two
39
Tech. Notes on DW Methods
October 1994 - Section IV
Mandatory Method Modifications
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METHOD 524.2, REV. 4.0 (R3) QUALITY ASSURANCE, VOC DATA
This Technical Note corrects or clarifies quality assurance steps in
Method 524.2, Rev. 4.0 (R3), and provides data for two VOCs that was omitted
in the published method.
Changes in Quality Assurance Procedures
EPA is changing some instruttions in Sections 9 (quality control) and 10
(calibration) of Method 524.2 that may be conflicting or confusing. The
changes described in this Note also apply to Method 502.2, Rev. 2.0 (R16) to
the extent that the same problems are in the quality control (Section 10) and
calibration (Section 9).
Section 9.3, Initial Demonstration of Accuracy --
EPA has been asked to make the accuracy criteria (±20%), which are part
of an initial demonstration of capability (IDC), in Sect. 9.3.3 of Method
524.2 the same as the accuracy criteria (±30%) in the section on continuing
calibration checks (Sect. 10.3.5). These criteria will not be changed. EPA
specified different criteria, because the IDC and Continuing Calibration
measurements are evaluating different controls. EPA believes the IDC
measurement, which requires analysis of a series of laboratory fortified
blanks, should be more accurate than the Continuing Calibration measurement.
To explain this difference in accuracy criteria, and to remove an incomplete
reference to the SDWA, Sect. 9.3.3 is revised in this Note.:
Section 9.3.3 is superseded in its entirety as follows:
"Some analytes, particularly early eluting gases and late eluting higher
molecular weight compounds, will be measured with less accuracy and
precision than other analytes. However, the accuracy and precision for
all analytes must fall within the limits expressed below. If these
criteria are not met for an analyte of interest, take remedial action and
repeat the measurements for that analyte until satisfactory performance
is achieved. For each analyte, the mean accuracy must be 80-120% (i.e.
an accuracy of ± 20%). The precision of the recovery (accuracy) for each
analyte must be less than twenty percent (<20%). These criteria are
different than the ± 30% response factor criteria specified in Sect.
10.3.5. The criteria differ, because the measurements in Sect. 9.3.3 as
part of the initial demonstration of capability should be more stringent
than the continuing calibration measurements in Sect. ,10.3.5."
i
Section 9.6 LFB Criteria —
This step in Method 524.4 requires a single laboratory fortified blank
(LFB) to be measured with each batch of samples, and with an accuracy that is
specified in Sect. 9.3.3 (i.e. ±20%), whereas Sect. 10.3.5 requires the same
sample be analyzed with an accuracy of +30%. EPA is removing this conflict by
changing the accuracy requirement to be ±30% in Sect. 9.6.
Tech. Notes on DW Methods
October 1994 - Section IV
40 Mandatory Method Modifications
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Section 9.6 is superseded in its entirety as follows:
"Use the procedures and criteria in Sects. 10.3.4 and 10.3.5 to evaluate
the accuracy of the measurement of the laboratory fortified blank (LFB),
which must be analyzed with each batch of samples that is processed as a
group within a work shift. If more than 20 samples are in a work shift
batch, analyze one LFB per 20 samples. Prepare the LFB with the
concentration of each analyte that was used in the Sect. 9.3.3 analysis.
If the acceptable accuracy for this measurement (±30%) is not achieved,
the problem must be solved before additional samples may be reliably
analyzed.
Since the calibration check sample in Sect. 10.3:5 and the LFB are made
the same way and since procedural standards are used, the sample analyzed
here may also be used as the calibration check in Sect. 10.3.5. Add the
results of the LFB analysis to the control charts to document data
quality."
Section 9.5 LRB Analysis — |
This step in Method 524.2 states that a field reagent blank may be used
in lieu of a laboratory reagent blank (LRB). This is not correct. An LRB
must always be analyzed with each batch (as defined at Sect. 9.6) of 20
samples. This Note amends Sect. 9.5 by deleting the erroneous second
sentence. ;
Section 9.5 is superseded in its entirety as follows:
"LABORATORY REAGENT BLANKS (LRB) — With each batch of samples processed
as a group within a work shift, analyze a LRB to determine the background
system contamination."
Section 9.7 FRB Analysis —
This step in Method 524.2 states that a "field reagent blank should be
analyzed" with each set of samples. This may cause unnecessary work. A field
reagent blank is collected as a precaution against false positive results that
may occur if the sample is contaminated in the field. Thus, a field reagent
blank analysis is only required when contamination is detected in the
compliance sample. This Note clarifies when the samples must be analyzed by
amending the first sentence in Sect. 9.7.
Section 9.7 is superseded in its entirety as follows:
"If a water sample is contaminated with an analyte, verify that it is not
a sampling error by analyzing a field reagent blank. The results of
these analyses will help define contamination resulting from field
sampling, storage and transportation activities. If the field reagent
blank shows unacceptable contamination, the analyst should identify and
eliminate the contamination."
Tech. Notes on DW Methods
October 1994 - Section IV
41 Mandatory [Method Modifications
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Section 10, Calibration —
There can be a conflict between the instructions in Sect. 9.6 in Method
524.2, which define a batch as 20 samples, and Sect. 10.1, which requires
calibration every 8 hours. Since a typical chromatographic run exceeds 35
minutes, 20 samples are measured in about 11, not 8, hours. This Note removes
the potential conflict by explaining when calibration must be checked.
Section 10.1 is superseded in its entirety as follows:
"Demonstration and documentation of acceptable initial calibration is
required before any samples are analyzed. In addition, acceptable
performance must be confirmed intermittently throughout analysis of
samples by performing continuing calibration checks. These checks are
required at the beginning of each work shift, but no less than every 12
hours. Additional periodic calibration checks are good laboratory
practice. Since this method uses procedural standards, the analysis of
the laboratory fortified blank, which is required in Sect. 9.6 may be
used here as the calibration check sample."
Tech. Notes on DW Methods
October 1994 - Section IV
42 Mandatory Method Modifications
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Performance Data for cis-and-trans 1,3-dichloropropene
EPA omitted performance data for two unregulated VOCs, cis-
1,3-dichloropropene and trans-l,3-dichloropropene. The following table
replaces Table 7 in Method 524.2, Rev. 4.0. 1
TABLE 7. ACCURACY AND PRECISION DATA FROM SEVEN DETERMINATIONS
OF METHOD ANALYTES IN REAGENT WATER USING WIDE BORE
CAPILLARY COLUMN NUMBER 4
Compound
Acetone
Acrylonitrile
Ally! chloride
2-Butanone
Carbon disulfide
Chloroacetonitrile
1-Chlorobutane
t-Di chl oro-2-butene
1,1-Dichloropropanone
c-l,3-Dichloropropene
t- 1 , 3-Di chl oropropene
Di ethyl ether
Ethyl methacrylate
Hexachl oroethane
2-Hexanone
Methacrylonitrile
Methyl acryl ate
Methyl iodide
Methyl methacryl ate
4-Methyl -2-pentanone
Methyl -tert-butyl ether
Nitrobenzene
2-Nitropropane
Pentachl oroethane
Propionitrile
Tetrahydrofuran
True
Cone.
(M9/L)
1.0
1.0
1.0
2.0
0.20
1.0
1.0
1.0
5.0
0.20
0.10
1.0
0.20
0.20
1.0
1.0
1.0
0.20
1.0
0.40
0.40
2.0
1.0
0.20
1.0
5.0
Mean
Cone.
Detected
(ug/L)
1.6
0.81
0.90
2.7
0.19
0.83
0.87
1.3
4.2
0.20
0.11
0.92
0.23
0.18
1.1
0.92
1.2
0.19
1.0
0.56
0.52
2.1
0.83
0.23
0.87
3.9
Rel.
Std.
Dev.
(%)
5.7
8.7
4.7
5.6
15
4.7
6.6
8.7
7.7
3.1
14
9.5
3.9
10
12
4-2
12
3.1 ;
13
9.7
5.6 :
18
6.2
20
5.3
13 !
Method
Detect.
Limit
(/*9/L)
0.28
0.22
0.13
• 0.48
0.093
0.12
0.18
0.36
1.0
0.020
0.048
0.28
0.028
0.057
0.39
0.12
0.45
0.019
0.43
0.17
0.090
1.2
0.16
0.14
0.14
1.6
43
Tech. Notes on DW Methods
October 1994 - Section IV
Mandatory Method Modifications
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EPA METHOD 531.1 (R16) AND SM 6610 (R8), STORAGE OF SAMPLES
This Technical Note removes the requirement in Methods 531.1, Rev. 3.0
(R16) and SM 6610 (R8) to freeze the samples. Sect. 8.2.4 of Method 531.1
requires buffered samples to be stored at minus 10°C. EPA realizes that this
is impractical and unnecessary. After reviewing time storage data, EPA
concluded that samples buffered to a pH of 3 or less may be stored at 4°C.
The data supporting this conclusion is contained in Table 6610:11 of SM 6610.
To reflect this change this Note supersedes Sect. 8.2.4 of EPA Method
531.1 in its entirety as follows. Users of the Standard Method should make
appropriate changes to the procedures, which are described in Paragraph 2
(Sampling and Storage) of SM 6610.
"Samples must be iced or refrigerated at 4°C from time of collection
until analysis is begun. Although, preservation study results of up to
28 days indicate method analytes are not labile in water samples when
sample pH is adjusted to 3 or less, and samples are shipped and stored at
4°C, analyte lability may be affected by the matrix. Therefore, the
analyst must verify that the preservation technique is applicable to the
samples under study."
Tech. Notes on DW Methods
October 1994 - Section IV
44 Mandatory Method Modifications
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METHOD 551 (R15), PENTANE
:i
This Technical Note allows optional use of pentane as the extraction
solvent for some of the analytes in EPA Method 551 (R15). Since a change in
the extraction solvent in any method is a change in the chemistry of the
method, an alternative solvent must be validated and approved by EPA for each
method analyte. EPA has approved only methyl t-butyl ether (MTBE) and pentane
for use as extraction solvents in Method 551. Pentane may not be used to
extract chloral hydrate; MTBE is approved for all Method 551 analytes.
Tech. Notes on DW Methods
October 1994 - Section IV
45 Mandatory Method Modifications
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EPA METHOD 549.1 (R3), SAMPLE CONTAINERS
This Technical Note clarifies that the amber sample bottle specified in
Section 6 (Equipment and Supplies) of Method 549.1, Rev. 1.0 (R3), can be made
of any type of plastic. The bottle does not have to be PVC as stated in the
method.
Tech. Notes on DW Methods
October 1994 - Section IV
46 Mandatory Method Modifications
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ALTERNATIVE LIQUID-SOLID EXTRACTION CARTRIDGES AND DISKS
This Technical Note provides criteria for judging the equivalency of
liquid-solid .extraction (LSE) cartridges and disks for use in methods that
allow use of LSE technology. This Note supersedes the phrase "or equivalent"
that is used in some methods to describe selection of alternative LSE
cartridges or disks. Although EPA welcomes innovative LSE technology, EPA
will not approve technology that compromises the reliability of the analysis.
Liquid-solid extraction is performed using various sorbents that are
either packed into a cartridge or enmeshed in a disk of inert support
material. EPA methods describe the cartridge or disk that was used to develop
the LSE procedure, and to produce the data which is published in the method.
If a product is mentioned in the methods, it is for information purposes only.
EPA believes various LSE cartridges and disks may be tised, provided they
meet all quality control requirements of the method, and provided they contain
a sorbent that uses the same physicochemical principles as the cartridge or
disk that is described in the approved LSE method. To demonstrate that
alternative LSE cartridges and disks meet all quality control criteria, the
analyst must be aware of the chemistry of the method. For example, in
evaluating Method 552.1 the recovery of the free acid (not a chemical
derivative) from the water sample must be tested with the alternative LSE
cartridge or disk.
In judging LSE disk media, both the sorbent and the support must be
evaluated. In the case of sorbents, similarities in polarity are not
sufficient. For example, a C18-Silica sorbent may not perform the same as a
styrene divinylbenzene copolymer sorbent. Thus, these sorbents would not be
considered to be equivalent. In judging supports, any physical support used
to hold the sorbent is acceptable provided the support is inert and compatible
with the solutions or solvents required in the conditioning and elution steps
of the method. However, any sorbent conditioning or elution steps, which are
specified in the method must not be modified or eliminated to accommodate the
support material. For example, Method 552.1 was developed and validated with
ion exchange cartridges to determine dalapon and haloacetic acids. To
efficiently extract the acids, the ion exchange resin must ,be activated with a
sodium hydroxide rinse. In judging the equivalency of an alternative disk EPA
would still require the rinse, because EPA has no data to support making the
rinse optional.
Tech. Notes on DW Methods
October 1994 - Section IV
47 Mandatory Method Modifications
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SECTION V. RECOMMENDED METHOD MODIFICATIONS
This section contains several optional procedures and recommended
modifications to compliance methods. Each optional or recommended procedure
is on a separate page to allow users to remove it, and place it with the
applicable method(s). The parenthetical number (R), which appears adjacent to
method citations in this section, refers to the publication in Section VI
(References) that contains the referenced method.
Tech. Notes on DW Methods
October 1994 - Section V
48 Recommended Method Modifications
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METHOD 100.1 (R18), ASBESTOS GUIDANCE
This Technical Note does not change Method 100.1 (R18J. It describes how
to make some steps in the method specifically applicable to the drinking water
standard of asbestos fibers greater than 10 jm in length. This guidance is
needed because the asbestos method was not designed specifically for measuring
fibers greater than 10 /m in length, and because laboratories may not wish to
use an ozone/UV generator to prepare the sample for analysis.
EPA METHOD 100.1
DETERMINATION OF ASBESTOS FIBERS IN WATER
OGWDW GUIDANCE AND CLARIFICATION FOR DRINKING WATER
Approximately 800 ml of sample should be taken in 1-L bottles.
Glass sampling bottles are preferable to plastic. If plastic
bottles are used, polyethylene is better than polypropylene. Do not
use acid or mercuric chloride as preservatives. Before collecting
the sample, the water must be allowed to run until the temperature
has stabilized, indicating that the water is representative of the
main water line. Samples must be taken in duplicate. Store samples
in the dark at 4°C.
To avoid use of the ozone, ultraviolet (UV) generator, samples must
be filtered on the polycarbonate (PC) filter in the laboratory
within 48 hours of collection. If the holding time is exceeded, the
sample must be treated to break down microbiological contaminants.
This is done immediately prior to filtration by treating the sample
in the original container with ozone, UV-light, and resonicating it
to disperse the fibers.
Up to 5 samples may be composited. Sample compositing must be done
in the laboratory on samples which are less than 48-hours-old or
have been individually ozone/UV treated in their original sample
containers. Samples must be sonicated and equal amounts withdrawn
to make up the composite. It may also be prudent to filter an
aliquot of each individual sample for analysis in case the composite
sample exceeds 1/5 of the MCL (1.4 MFL >10 /fm long). If this is not
done, the original samples can only be filtered if they are less
than 48-hours-old and have been resonicated or have been retreated
with ozone-UV and resonicated.
Only 0.1 /zm pore size PC filter membranes may be used. Filters must
be taken from a lot which has been prescreened for background
contamination. This is particularly important if fibers less than
10 urn are to be counted because PC filters may be contaminated with
asbestos fibers shorter than 10 /m. The PC filter must be backed by
a methyl cellulose ester (MCE) filter to diffuse the vacuum across
the membrane. Use <5 /im pore-size MCE membrane as the backing
filter.
49
Tech. Notes on DW Methods
October 1994 - Section V
Recommended Method Modifications
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8.
A filtration apparatus with straight vertical sides is preferred to
one with tapered sides to avoid loss of fibers settling on tapered
sides of the funnel.
States agencies may choose to require the counting of fibers less
than 10 urn long to help judge the condition of asbestos/cement
pipes. Certification lists must identify whether labs count all
fibers or only those over 10 jam, and whether the lab is certified by
a state or EPA region.
A calibrated magnification of at least 10,OOOX ±5% is adequate for
counting fibers over 10 /zm in length. A minimum spot size of 250 nm
or smaller is required for this analysis.
For compliance analysis of asbestos in drinking water samples, an
analytical sensitivity <200,000 fibers per liter (0.2MFL) is
required, subject to the following stopping rules:
a.
Analysis may be terminated at the completion of the grid
opening during examination of which an analytical sensitivity
of 0.2MFL is achieved, or at the completion of the grid opening
which contains the 100th asbestos fiber over 10 urn in length.
whichever-occurs first.
b.
A minimum of 4 grid openings must be counted, even if this
results in counting more than 100 asbestos fibers over 10 urn in
length. ;
j
The grid openings examined must be drawn about equally from a
minimum of 3 specimen grids.
9. Counting rules:
a.
b.
c.
d.
e.
Count fibers with an aspect ratio >3:1. ;
Count a fiber bundle as a single fiber with a width equal to an
estimate of the mean bundle width, and length equal to the
maximum length.
Count individual asbestos fibers and bundles within clusters
and matrices, as long as they meet the definitions of fibers
and bundles as described in 9A and 9B.
Count the fibers which intersect the top and left sides of the
grid opening and record as twice their visible length. Do not
record fibers intersecting the bottom and right sides of the
grid opening. ]
Count only one end of the fiber to avoid possibly counting a
fiber more than once.
50
Tech. Notes on DW Methods
October 1994 - Section V
Recommended Method Modifications
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10. Fiber identification criteria:
a. Each fiber suspected to be chrysotile must first be examined by
electron diffraction following the procedure in Figure 15 of
the EPA method. If the characteristic electron diffraction
(ED) pattern is observed, the fiber shall be classified as CD
(chrysotile identified by diffraction pattern). If no pattern
is observed or the pattern is not distinctive, the fiber shall
be examined by EDXA (energy dispersive x-ray analysis) and
classified according to the EPA method. Only chrysotile fibers
classified as CD, CMQ (chrysotile identified by morphology and
semi-quantitative EDXA) or CDQ (chrysotile identified by
morphology, electron diffraction and semi-quantitative EDXA)
shall be included in the calculation of the concentration for
the purposes of this regulation. '
b. Each fiber suspected to be amphibole must first be examined by
electron diffraction following the procedure in Figure 18 of
the EPA Method. Each fiber must be examined by EDXA. -If a
random orientation electron diffraction pattern showing a 0.53
nm layer spacing is obtained, and the elements and peak areas
of the EDXA spectrum' correspond to those of a known amphibole
asbestos, the fiber shall be classified as ADQ (amphibole
identified by diffraction and semi-quantitative EDXA). If the
random orientation electron diffraction pattern cannot be
obtained, is incomplete, or is not recognizable as a non-
amphibole pattern, but the elements and the peak areas of the
EDXA spectrum correspond to those of a known amphibole
asbestos, the fiber shall be classified as AQ (amphibole
identified by semi-quantitative EDXA). Only amphibole fibers
classified as ADQ, AQ, AZQ (amphibole identified by zone axis
electron diffraction and semiquantitative EDXA) and AZZQ
(amphibole identified by 2 zone axes electron diffraction and
semi-quantitative EDXA) shall be included in, the calculation of
asbestos concentration. '.
11.
It is not necessary to calculate the mass concentration of asbestos
for this regulation. Concentrations must be reported in MFL>10 urn
When no asbestos fibers greater than 10 /ym are found, report <0 2
MFL>10 IM.
51
Tech. Notes on DW Methods
October 1994 - Section V
Recommended Method Modifications
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METHOD 502.2 (R16), USE OF THE PID
This Technical Note clarifies when a photoionization detector (PID) is
not required. Method 502.2, Rev. 2.0 (R16).requires the use of a PID to
measure volatile organic compounds (VOCs) that cannot be measured with an
electrolytic conductivity detector. If only halogenated analytes, such as the
tnhalomethanes, are to be measured, a PID is not needed. This option will
al-low laboratories to use this VOC method for determination of total
trihalomethanes as specified at §141.30 without the expense of a PID.
Tech. Notes on DW Methods
October 1994 - Section V
52 Recommended Method Modifications
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METHODS 502.2 (R16), 524.2 (R3) AND 551 (R15) SAMPLE DECHLORINATION
This Technical Note provides guidance to help laboratories correctly
dechlorinate samples for compliance with the total trihalomiethane (TTHM)
monitoring requirements under 40 CFR 141.30 using EPA Method 502.2, Rev. 2.0
(R16) or 524.2, Rev. 4.0 (R3) or 551 (R15), or when VOCs and THMs are to be
measured in the same sample. This guidance also applies to use of EPA Methods
502.1, 503.1 and 524.1 (R16). These methods are not approved for THM analysis
under 40 CFR 141.30, but some laboratories may wish to use these methods for
analysis of samples other than compliance samples.
This guidance supersedes the discussion on ascorbic acid contained in the
introduction (p. 3) to the 1991 EPA manual (R16). The Agency believes revised
guidance is warranted because laboratories may be confused by the variety of
preservation procedures described in the five methods. The reagent available
to dechlorinate samples varies with the method used, or with the analyte to be
measured.
i
Laboratories must carefully follow the preservation procedure described
in each method, especially the order in which reagents are added to the
sample. Each method allows use of one or more dechlorination reagents
depending on the analyte to be measured. These reagents remain available for
use, but EPA strongly recommends use of sodium thiosulfate as the
dechlorination reagent, because the Agency has more performance data
demonstrating the effectiveness of this chemical than for other dechlorination
reagents.
One exception to this recommendation is ascorbic acid must be used when
vinyl chloride and other gases are measured with a mass spectrometer, because
sodium thiosulfate in an acidified sample generates a gas that interferes with
the analysis. EPA cautions that samples dechlorinated with ascorbic acid must
be acidified immediately, as directed in the method. Other exceptions, such
as for analysis of haloacetonitriles are described in Section 8 of EPA Method
551 (R15).
Tech. Motes on DW Methods
October 1994 - Section V
53 Recommended Method Modifications
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METHOD 504.1 (R5), CHROMATOGRAPHIC INTERFERENCES
Although this Technical Note discusses misidentifications that may occur
when measuring 1,2-dibromoethane (EDB) or dibromochloropropane (DBCP) with
Method 504.1 (R5), the guidance and warnings provided here are applicable to
the interpretation of analytical results from any method. Volatile organic
chemicals (VOCs) or trihalomethanes (THMs) can cause chromatographic
interference problems if these chemicals are in the sample, and coelute on the
column used to separate and identify EDB or DBCP. Interferences can lead to
false positive results, if a coeluting VOC or THM is misidentified as EDB or
UBCP.
i
Since any method, even one that uses a selective detector, is subject to
false positive results, any result that exceeds an action concentration must
be rigorously confirmed^to avoid "unnecessary action. Method 504.1 uses an
electron capture detector that is very sensitive and stable. Although this
detector is excellent at detecting very low concentrations of halogenated
compounds, it is subject to many interferences.
i
Sections 4.3 and 6.6.2 in Method 504.1 note that a common THM disin-
fection by-product in chlorinated water supplies, dibromochloromethane, can
elute close to EDB. This means in the initial demonstration of capability a
laboratory must determine the retention time of dibromochloromethane or other
compounds that might coelute with the method analytes. A relative response
factor and retention time for each possible interfering amalyte should be
M^™?1^?- These retention times can be determined by using procedures in
Method 551 to prepare and analyze THM and VOC standards for analysis on a
Method 504.1 chromatographic column. This information can be obtained more
easily if a DB-1 column is used in Method 504.1 and the retention times are
compared to the THM and VOC retention times obtained with the DB-1 column used
in Method 551.
Confirmation procedures must be followed before taking action on a
result. Confirmation of potential Method 504.1 or Method 551 chromatographic
interferences can be obtained with an inexpensive purge-and-trap analysis (EPA
Method 502.2 (R16) or 524.2 (R3)). These methods can identify interfering
trihalomethanes, or VOCs that might occur with EDB if the source of EDB were
unleaded gasoline (cf. Sect. 2.3). Although Method 524.2 is not as sensitive
as Method 504.1, EDB can be measured at concentrations greater than 0 06 uq/L
Other confirmation procedures, which are described in Method 504 1 are- '
analysis on a second column with dissimilar retention times (Sect/6 6 2) and
changing the temperature program to provide sufficient separation between EDB
and dibromochloromethane (Sect. 9.1.2).
EPA emphasizes that knowledge of probable contaminants in a sample, and
of method interferences are key parts of quality assurance and good data
interpretation when using arvy. analytical method. Laboratories reporting data
must realize that interpreters of occurrence data are often unfamiliar with
weaknesses in an analytical method, and that officials may enforce on the data
as provided by the laboratory. EPA strongly encourages data reviewers to
Tech. Notes on DW Methods
October 1994 - Section V
54 Recommended Method Modifications
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question the plausibility, not just the possibility, of a result, and not
assume that a laboratory has always eliminated analytical error. A skeptical
approach is especially important when initial sample results are being
interpreted.
55
Tech. Notes on DW Methods
October 1994 - Section V
Recommended Method Modifications
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METHODS 505, 507, 508 (R16), INTERCHANGE OF DETECTORS
This Technical Note clarifies under what conditions a laboratory may use
?Mnn?r.anrnleMtr?n:capture detectolr (ECD) or a nitrogen-phosphorous detector
(NPD) in EPA Methods 505, Rev. 2.0; 507, Rev. 2.0; or 508, Rev. 3.0 (R16)
Laboratories may wish to use a different detector to decrease method detection
limits. For example, use of an NPD in Method 505 can increase the sensitivity
cL theJa22lys1! for alachlor> atrazine and simazine. Section 6.8.3 of Methods
'
. ..
n and S??: 10'4 of Methods 505» 507 and 508 al''°w use of an ECD or
NPD detector provided the initial demonstration of capability criteria are
met. These criteria are specified in Section 10 of each method.
Section 5.8.3 of Methods 507 and 508 note that a mass spectrometer might
be used. This Note withdraws this recommendation, which was made before
Method 525.2 was available. EPA no longer recommends use of a mass
spectrometer with Methods 507 and 508, because important tuning and
calibration procedures for the mass spectrometer are not described in either
method, and because Method 525.2 thoroughly describes these procedures
Method 525.2 is approved for determination of all Method 507 and 508 analytes
except PCBs as the seven Aroclors. '
Tech. Notes on DW Methods
October 1994 - Section V
56 Recommended Method Modifications
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EPA METHODS 507, 508, 515.1 (R16), MERCURIC CHLORIDE
This Technical Note removes the requirement to use mercuric chloride,
because concerns have been raised about the environmental hazards and costs
associated with disposal of mercuric compounds. Mercuric chloride is used as
a biocide in EPA Methods 507, Rev. 2.0; 508, Rev. 3.0; and 515.1, Rev. 4.0
(R16). Since drinking water usually exhibits limited biological activity, EPA
is removing the requirement under Sect. 8.2 of Methods 507, 508, and 515.1 to
use mercuric chloride as a bactericide. To minimize the possibility of
occasional false-negative results, the Agency would still require the use of
mercuric chloride in any drinking water sample that might be expected to
exhibit biological degradation of a target pesticide. \
There are also environmental and economic concerns about addition of acid
to drinking water samples in the VOC methods (Methods 502.2, 524.2, and 551)
However, EPA will not remove this requirement, because EPA has ,data that
demonstrates microbiological degradation of VOCs in drinking water samples.
Tech. Notes on DM Methods
October 1994 - Section V
57 Recommended Method Modifications
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EPA METHOD 1613, DIOXIN (R17)
This Technical Note does not change Method 1613 (R17). It describes how
to make some steps in the method specifically applicable to measurement of
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Guidance is needed because Method
1613 was written to determine many isomers of dioxins and furans, but under
the Safe Drinking Water Act, EPA only regulates the 2,3,7,8-TCDD isomer.
Also, information to determine if the drinking water sample needs to be
filtered is not clearly provided in Method 1613. Using this guidance will
substantially decrease the cost of Method 1613, because it eliminates many
costly steps that are not required when only TCDD is to be determined.
EPA METHOD 1613
OGWDW GUIDANCE AND CLARIFICATION FOR ANALYSIS OF
2,3,7,8-TETRACHLORODIBENZO-p-DIOXIN (TCDD) IN DRINKING WATER
1. The only isotopically labeled compounds which are necessary for
calibration and quantitation in addition to the native 2,3,7,8-TCDD are
13C12 2,3,7,8-TCDD (the spiking compound), 37C14 2,3,7,8-TCDD (the clean-
up standard), and %2 1,2,3,4-TCDD (the internal standard).
2. During calibration, selected ion current profiles of only the compounds
in item 1 above need be obtained according to directions in Sect. 7 of
the method by monitoring the exact masses specified for these compounds
in Table 3 of the method at >10,000 resolving power. The relative
abundances must meet the criteria specified in the method. There must
be at least baseline resolution in the chromatogram between the 1,2,3,4-
TCDD and the 2,3,7,8-TCDD isomers.
3. If the sample is colorless, odorless, has a turbidity of one (1) NTU or
less and consists of a single phase, filtration is not required, and the
sample may be analyzed according to Sect. 11.1 of the method. Turbidity
must be measured with an approved method. Any sample containing
multiple phases, or having a turbidity of more than one (>1) NTU must be
filtered. The filter particulate must be analyzed according to Sect.
11.2 of the method.
4. Since drinking water samples are relatively free from interferences, the
optional clean-up steps described in the method probably will not be
needed for most samples.
58
Tech,, Notes on DW Methods
October 1994 - Section V
Recommended Method Modi fi cati ons
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SECTION VI. EPA CONTACTS AND METHOD REFERENCES
OBTAINING METHODS AND TECHNICAL ASSISTANCE
For assistance in obtaining copies of EPA methods, or for answers to
technical questions about drinking water methods please contact:
U.S. EPA, Environmental Monitoring Systems Laboratory
Chemistry Research Division (MC 564)
Cincinnati, OH 45268-0001
Telephone: 513 569-7586
CERTIFICATION AND REGULATORY ASSISTANCE
For answers to questions about laboratory certification, the EPA Labcert
Bulletin, and the regulatory status of drinking water methods please contact:
U.S. EPA, Technical Support Division
Drinking Water Quality Assessment Branch (MC 140)
ATTN: Methods and Laboratory Certification
Cincinnati, OH 45268-0001
Telephone: 513 569-7938
REFERENCES
Rl.
R2.
R3.
R4.
R5.
R6.
R7.
Approved EPA Methods 200.7, 200.8, 200.9, and 245.1 are contained in
"Methods for the Determination of Metals in Environmental Samples -
Supplement I," May 1994, NTIS PB94-184942.
EPA Method 100.2, "Determination of Asbestos Structures over 10 jjm in
Length in Drinking Water," June 1994, NTIS PB94-201902.
Approved EPA Methods 515.2, 524.2, 548.1, 549.1, 552.11 and 555 are
contained in "Methods for the Determination of Organic Compounds in
Drinking Water - Supplement II," August 1992, NTIS PB92-207703.
Approved EPA Methods 180.1, 300.0, 335.4, 353.2 and recommended Method
375.2 are contained in "Methods for the Determination of Inorganic
Substances in Environmental Samples," August 1993, NTIS PB94-121811.
EPA Method 504.1, "1,2-Dibromoethane (EDB), l,2-Dibromo-3-chloropropane
(DBCP), and 1,2,3-Trichloropropane (123TCP) in Water by Microextraction
and Gas Chromatography," 1993.
EPA Method 508.1, Rev. 1.0, "Determination of Chlorinated Pesticides,
Herbicides, and Organohalides by Liquid-Solid Extraction and Electron
Capture Gas Chromatography," 1994.
EPA Method 525.2, Rev. 1.0, "Determination of Organic Compounds in
Drinking Water by Liquid-Solid Extraction and Capillary Column Gas
Chromatography/Mass Spectrometry," March 1994.
59
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R8. Method 6610 "Carbamate Pesticides" is contained in Standard Methods for
the Examination of Water and Wastewater 18th Edition Supplement. 1994 may
be purchased from the American Public Health Association, 1015 Fifteenth
Street NW, Washington, D.C. 20005.
R9. GLI Method 2, "Turbidity" is available free from Great Lakes Instruments,
Inc., November 2, 1992.
RIO. Orion Technical Bulletin 601 "Standard Method of Test for Nitrate in
Drinking Water," July 1994 is identical to Orion WeWWG/5880, which had
previously been approved for nitrate analysis at 40 CFR 141.23(k)(l).
ATI Orion republished this method in 1994, and renumbered it as 601,
because the 1985 manual "Orion Guide to Water and Wastewater Analysis-,"
which contained WeWWG/5880, is no longer available. Technical Bulletin
601 is available free from ATI Orion, 529 Main Street, Boston, MA 02129.
Laboratories wishing to use the Orion method should be aware that SM
4500-N03-D, which is published in the 18th edition of Standard Methods
for the Examination of Water and Wastewater. is equivalent to Orion 601.
Rll. The American Society for Testing and Materials (ASTM) annually reprints
all of the methods contained in the Annual Book of ASTM Methods. Vols.
11.01 and 11.02, including methods that have not been editorially or
technically revised. Thus, it is permissible to use any edition that
contains the EPA-approved version of the method that is approved. The
Annual Book of ASTM Methods may be purchased from ASTM, 1916 Race Street,
Philadelphia, PA 19103.
R12. Eighteenth edition of Standard Methods for the Examination of Water and
Wastewater. 1992 may be purchased from the American Public Health
Association, 1015 Fifteenth Street NW, Washington, D.C. 20005.
R13. EPA Method 245.2, "Mercury, Automated Cold Vapor Technique,"
Environmental Monitoring Systems Laboratory, Cincinnati, OH 45268, 1974.
Also contained in reference 14.
R14. "Methods for Chemical Analysis of Water and Wastes," EPA, March 1983,
NTIS PB84-128677.
R15. Approved EPA Methods 506, 547, 550, 550.1 and 551 are contained in
"Methods for the Determination of Organic Compounds in Drinking Water —
Supplement I," July 1990, NTIS PB91-146027.
R16. Approved EPA Methods 502.2, 505, 507, 508, 508A, 515.1 and 531.1, and
Methods 502.1, 503.1, and 524.1, which will be withdrawn are contained in
"Methods for the Determination of Organic Compounds in Drinking Water,"
December 1988, Revised July 1991, NTIS PB91-231480.
R17. EPA Method 1613, Revision B, "Tetra-through-Octa- Chlorinated Dioxins and
Furans by Isotope-Dilution HRGC/HRMS," October 1994, NTIS PB95-104774.
60
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R18. EPA Method 100.1, "Analytical Method for the Determination of Asbestos
Fibers in Water," September 1983, NTIS PB83-260471.
R19. Methods 1-3300-85, 1-1030-85, 1-1601-85, 1-2598-85, 1-1700-85 and 1-2700-
85 in Techniques of Water Resources Investigations of the U.S. Geological
Survey, Book 5, Chapter A-l, 3rd ed., U.S. Geological Survey, Books and
Open File Reports Section, Box 25425, Federal Center, Denver, CO 80225-
0425, 1989.
R20. "Waters Test Method for Determination of Nitrite/Nitrate in Water Using
Single Column Ion Chromatography," Method B-1011 is available free from
Mi 11ipore Corporation, Waters Chromatography Division, 34 Maple Street,
Milford, MA 01757.
R21. Industrial Method No. 129-71W, "Fluoride in Water arid Wastewater,"
December 1972, and Method No. 380-75WE, "Fluoride in Water and
Wastewater," February 1976 are available free from Technicon Industrial
Systems, Tarrytown, NY 10591.
R22. Method 1-2601-90 in Methods of Analysis by the U.S. Geological Survey
National Water Quality Laboratory—Determination of Inorganic and Organic
Constituents in Water and Fluvial Sediments. Open File Report 93-125 is
available from U.S. Geological Survey, Books and Open File Reports
Section, Box 25425, Federal Center, Denver, CO 80225-0425, 1993.
References Rl to R4 are available for a fee through the National
Technical Information Service (NTIS), which is located at U.S. Department of
Commerce, 5285 Port Royal Road, Springfield, Virginia 22161; the toll-free
number is (800)-553-6847. Until references R5 to R7 are published in "Methods
for the Determination of Organic Compounds in Drinking Water - Supplement
III," these methods are available free from EPA-EMSL-Cincinnati, Cincinnati
OH 45268. The phone number is (513) 569-7586. The "Supplement III" manual is
expected to be published by EMSL-Cincinnati in late 1995.
61
• U.S. GOVERNMENT PRINTING OFFICE: 1995-650-00<>/00220
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