United States Office of Acid Deposition, EPA/600/4-88/031
Environmental Protection Environmental Monitoring and August 1988
Agency Quality Assurance
Washington DC 20460
Research and Development
c/EPA Eastern Lake Survey
Phase II
Analytical Methods Manual
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EASTERN LAKE SURVEY-PHASE II
ANALYTICAL METHODS MANUAL
by
Kerfoot, T. E. Lewis, D. C. Hillman, M. L. Faber, and T. Mitchell-Hall
Lockheed Engineering and Management Services Company, Inc.
Las Vegas, Nevada 89119
Contract No. 68-03-3249
Project Officer
Robert D. Schonbrod
Exposure Assessment Research Division
Environmental Monitoring Systems Laboratory
Las Vegas, Nevada 89193-3478
ENVIRONMENTAL MONITORING SYSTEMS LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
LAS VEGAS, NEVADA 89193-3478
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NOTICE
The information in this document has been funded wholly or in part by
the U.S. Environmental Protection Agency under contract number 58-03-3249 to
Lockheed Engineering and Management Services Company, Inc., and contract number
63-03-3246 to Northrop Services, Inc. It has been subject to the Agency's peer
and administrative review, and it has been approved for publication as an EPA
document.
The mention of trade names or commercial products does not constitute
endorsement or recommendation for use.
This document is one volume of a set which fully describes Phase II of the
National Lake Survey. The complete document set includes the major data report,
pilot survey data report, quality assurance plan, analytical methods manual,
field operations report, processing laboratory operations report, and quality
assurance report. Similar sets are being produced for each Aquatic Effects
Research Program component project. Colored covers, artwork, and use of the
project name in the document title serve to identify each companion document
set.
Proper citation of this document is:
Kerfoot, H. B., T. E. Lewis, D. C. Hillman, and M. L. Faber. 1988.
Eastern Lake Survey-Phase II: Analytical Methods Manual. EPA/600/ /
U.S. Environmental Protection Agency, Environmental Monitoring Systems
Laboratory, Las Vegas, Nevada.
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ABSTRACT
The National Surface Water Survey is part of the National Acid Precipita-
tion Assessment Program. This survey is designed to evaluate the current water
chemistry of lakes and streams and to select regionally representative surface
waters for a long-term monitoring program to study changes in aquatic re-
sources. A synoptic survey of lakes in the eastern United States was included
in the first phase of the National Surface Water Survey. The Eastern Lake
Survey-Phase II involves a seasonal evaluation of within-lake chemical vari-
ability for a subset of lakes sampled during Phase I.
The U.S. Environmental Protection Agency requires a program of data col-
lection activities which ensures that the resulting data are of known quality
and are suitable for their intended purpose. In addition, the data must be
consistent and comparable. For these reasons, the same reliable, detailed,
analytical methodology must be available to and must be used by all analysts
participating in the study.
This manual describes and references field and laboratory analytical
methods and internal quality control procedures that will be used to process
and analyze samples for Phase II of the Eastern Lake Survey. Phase II methods
and procedures that were modified from Phase I activities, as well as new
methods and procedures that were not used during Phase I, are described in
detail here. Methods and procedures that are identical to those used during
Phase I are not described here; however, appropriate references are made to the
Phase I analytical methods manual.
The physical parameters and analytes to be measured and the corresponding
analytical methods to be used during Phase II are listed below. Each new or
modified physical parameter, analyte, and method is identified by an asterisk.
Physical Parameter or Analyte
1. Acid neutralizing capacity
2. Aluminum, nonexchangeable PCV-
reactive*
3. Aluminum, total
Method
Titration and Gran analysis
(referred to as alkalinity in
previous surveys)
Cation-exchange followed by flow-
injection colorimetric analysis*
Atomic absorption spectroscopy
(graphite furnace)
-------
Physical Parameter or Analyte
4. Aluminum, total extractable
5. Aluminum, total PCV-reactive*
6. Ammonium, dissolved
7. Base neutralizing capacity
8. Calcium, dissolved
9. Chloride, dissolved
10. Chlorophyll a*
11. Fluoride, total dissolved
12. Inorganic carbon, dissolved
13. Iron, dissolved
14. Magnesium, dissolved
15. Manganese, dissolved
16. Nitrate, dissolved
17. Nitrogen, total*
18. Organic carbon, dissolved
19. pH
Method
Extraction with 8-hydroxyquinoline
into methyl isobutyl ketone
followed by atomic absorption
spectroscopy (graphite furnace)
Flow-injection colorimetric
analysis*
Automated colorimetry (phenate)
Titration and Gran analysis
(referred to as C02~acidity in
previous surveys)
Atomic absorption spectroscopy
(flame) or inductively coupled
plasma emission spectroscopy
Ion chromatography
Fluorometric and high performance
liquid chromatographic analysis*
Ion-selective electrode and meter
Instrument (acidification, C02
generation, infrared radiation
detection)
Atomic absorption spectroscopy
(flame) or inductively coupled
plasma emission spectroscopy
Atomic absorption spectroscopy
(flame) or inductively coupled
plasma emission spectroscopy
Atomic absorption spectroscopy
(flame) or inductively coupled
plasma emission spectroscopy
Ion chromatography
Flow-injection analysis*
Instrument (ultraviolet-promoted
oxidation, C02 generation,
infrared radiation detection)
pH electrode and meter
IV
-------
Physical Parameter or Analyte
20. Phosphorus, total
21. Potassium, dissolved
22. Silica, dissolved
23. Sodium, dissolved
24. Specific conductance*
25. Sulfate, dissolved
26. True color
27. Turbidity
Method
Automated colorimetry
(phosphomolybdate)
Atomic absorption spectroscopy (flame)
Automated colorimetry
(molybdate blue)
Atomic absorption spectroscopy (flame)
Conductivity cell and meter*
Ion chromatography
Comparison to platinum-cobalt
color standards
Instrument (nephelometer)
This report was submitted in fulfillment of contract number 68-03-3249 by
Lockheed Engineering and Management Services Company, Inc. under the sponsor-
ship of the U.S. Environmental Protection Agency. This report covers a period
from March 1984 to November 1986 and work was completed as of November 1987.
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ACKNOWLEDGMENTS
Contributions provided by the following individuals were essential
to the completion of this methods manual and are gratefully acknowledged:
Mark Peden (^Illinois State Water Survey), Kevin Cabbie, Lynn Creel man,
Sevda Drouse', Janice Engels, Cindy Mayer, John Nicholson, and Frank Morris
(Lockheed Engineering and Management Services Company, Inc.), James Kramer
(McMaster University), John Lawrence (National Water Research Institute),
Bruce LaZerte (Ontario Ministry of the Environment), John Nims (State of Maine,
Department of Environmental Protection), Dixon Landers (U.S. Environmental
Protection Agency), Howard May (U.S. Geological Survey), Peter Campbell
(University of Quebec), Mike Stainton (Canadian Freshwater Institute), Jim
Gibson (Colorado State University), and David DeWalle (Pennsylvania State
University).
VI
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Section T of C
Revision 4
Date: 9/87
'•>age 1 of 5
TABLE OF CONTENTS
Section Page Revision
Abstract iii of vi 4
Acknowledgments vi of vi 4
Figures 1 of 1 4
Tables 1 of 1 4
1.0 INTRODUCTION 1 of 9 4
1.1 Background 1 of 9 4
1.2 Spring Variability Study 3 of 9 4
1.3 Seasonal Surveys 4 of 9 4
1.3.1 Spring Seasonal Survey 4 of 9 4
1.3.2 Summer Seasonal Survey 4 of 9
1.3.3 Fall Seasonal Survey 4 of 9 4
1.4 Analytes and Physical Parameters Measured 5 of 9 4
1.4.1 Acid Neutralizing Capacity 5 of 9 4
1.4.2 Aluminum, Nonexchangeable
PCV-Reactive 5 of 9 4
1.4.3 Aluminum, Total 7 of 9 4
1.4.4 Aluminum, Total Extractable 7 of 9 4
1.4.5 Aluminum, Total PCV-Reactive .... 7 of 9 4
1.4.6 Base Neutralizing Capacity 7 of 9 4
1.4.7 Chlorophyll ^ 7 of 9 4
1.4.8 Inorganic Carbon, Dissolved 7 of 9 4
1.4.9 Ions, Dissolved (Ca, Cl~, F",
Fe, K, Mg, Mn, Ma, NH/, N03",
and S042") 8 of 9 4
1.4.10 Nitrogen, Total 8 of 9 4
1.4.11 Organic Carbon, Dissolved 8 of 9 4
1.4.12 pH 8 of 9 4
1.4.13 Phosphorus, Total 8 of 9 4
1.4.14 Silica, Dissolved '. 8 of 9 4
1.4.15 Specific Conductance 3 of 9 4
1.4.16 True Color 8 of 9 4
1.4.17 Turbidity 9 of 9 4
1.5 References 9 of 9 4
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Section T of C
Revision 4
Date: 9/87
Page 2 of 5
TABLE OF CONTENTS (Continued)
Section
2 0 MOBILE PROCESSING FACILITY OPERATIONS
2 1 Personnel
2 2 General Daily Operation
2.3 Procedures for Processing Surface Water
Samples
2.3.1 Sample Identification and Batch
Organization
2.3.2 Aliquot Preparation
2.3.3 Determination of Analytes and
Physical Parameters
2.3.4 Form Completion, Sample Shipment,
and Data Distribution
2.4 Procedures for Processing Snowpack Samples.
2.4.1 Sample Identification and Batch
Organization
2.4.2 Sample Preparation
243 Aliquot Preparation
2.4.4 Determination of Analytes and
Physical Parameters
2.4.5 Forms Completion, Sample Shipment,
and Data Distribution
2.5 Determination of DIC
2.6 Determination of pH
2.7 Determination of True Color
2.8 Determination of Turbidity
2.9 Fractionation and Determination of
Aluminum Soecies
?.9.1 Scope and Application
2.9.2 Summary of Method
Page
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2 of 43
5 of 43
5 of 43
5 of 43
9 of 43
9 of 43
9 of 43
15 of 43
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Revision
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Section T of
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Page 3 of 5
TABLE OF CONTENTS (Continued)
Section Page Revision
2.9.3 Interferences 21 of 43 4
2.9.4 Safety 21 of 43 4
2.9.5 Apparatus and Equipment 22 of 43 4
2.9.6 Reagents and Consumable Materials . 22 of 43 4
2.9.7 Sample Collection, Preservation,
and Storage 25 of 43 4
2.9.8 Calibration and Standardization .. 25 of 43 4
2.9.9 Quality Control 25 of 43 4
2.9.10 Procedure 26 of 43 4
2.9.11 Maintenance 31 of 43 4
2.9.12 Calculation 32 of 43 4
2.9.13 Precision and Accuracy 32 of 43 4
2.10 Determination of Total Nitrogen 32 of 43 4
2.10.1 Scope and Application 32 of 43 4
2.10.2 Summary of Method 34 of 43 4
2.10.3 Definitions 34 of 43 4
2.10.4 Interferences 34 of 43 4
2.10.5 Safety 34 of 43 4
2.10.6 Apparatus and Equipment 35 of 43 4
2.10.7 Reagents and Consumable Materials. 35 of 43 4
2.10.8 Sample Collection, Preservation,
and Storage 38 of 43 4
2.10.9 Calibration and Standardization. . 38 of 43 4
2.10.10 Quality Control 39 of 43 4
2.10.11 Procedure 39 of 43 4
2.10.12 Calculations 41 of 43 4
2.10.13 Precision and Accuracy 42 of 43 4
2.11 Collection, Preservation, and Storage of
Chlorophyll a_ Samples 42 of 43 4
2.12 References 42 of 43 4
3.0 ANALYTICAL LABORATORY OPERATIONS : 1 of 57 4
3.1 Summary of Operations 1 of 57 4
3.1.1 Sample Receipt and Handling. ... 1 of 57 4
3.1.2 Sample Analysis 1 of 57 4
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Section T of C
Revision 4
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Page 4 of 5
TABLE OF CONTENTS (Continued)
Section Page Revision
3.1.3 Internal Quality Control
Requirements 1 of 57 4
3.1.4 Data Reporting 11 of 57 4
3.2 Determination of ANC, 8NC, and pH 15 of 57 4
3.2.1 Scope and Application 15 of 57 4
3.2.2 Summary of Method 15 of 57 4
3.2.3 Interferences 15 of 57 4
3.2.4 Safety 16 of 57 4
3.2.5 Apparatus and Equipment 16 of 57 4
3.2.6 Reagents and Consumable Materials. 16 of 57 4
3.2.7 Sample Collection, Preservation,
and Storage 17 of 57 4
3.2.8 Calibration and Standardization. . 18 of 57 4
3.2.9 Quality Control 27 of 57 4
3.2.10 Procedure 31 of 57 4
3.2.11 Calculations 33 of 57 4
3.3 Determination of Ammonium 42 of 57 4
3.4 Determination of Chloride, Nitrate, and
Sulfate 42 of 57 4
3.5 Determination of Chlorophyll a. 42 of 57 4
3.5.1 Scope and Application 42 of 57 4
3.5.2 Summary of Method 42 of 57 4
3.5.3 Interferences 42 of 57 4
3.5.4 Safety 43 of 57 4
3.5.5 Apparatus and Equipment 43 of 57 4
3.5.6 Reagents and Consumable Materials. 44 of 57 4
3.5.7 Calibration 45 of 53 4
3.5.8 Quality Control 49 of 53 4
3.5.9 Procedure 50 of 53 4
3.5.10 Calculations '. 51 of 53 4
3.5.11 Precision and Accuracy 51 of 53 4
3.6 Determination of Dissolved Organic Carbon
and Dissolved Inorganic Carbon 51 of 57 4
3.7 Determination of Total Dissolved Fluoride . 52 of 57 4
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Section T of C
Revision 4
'Date: 9/87
Page 5 of 5
TABLE OF CONTENTS (Continued)
Section Page Revision
3.8 Determination of Total Phosphorus 52 of 57 4
3.9 Determination of Dissolved Silica 52 of 57 4
3.10 Determination of Specific Conductance ... 52 of 57 4
4
4
4
4
4
4
4
4
4
4
4
4
3.11 Determination of Metals (Al, Ca, Fe, K,
Mg, Mn, Na) by Atomic Absorption
Spectroscopy 55 of 57 4
3.12 Determination of Dissolved Metals (Ca, Fe,
Mg, and Mn) by Inductively Coupled
Plasma Emission Spectroscopy 55 of 47 4
3.13 References 56 of 47 4
APPENDICES
A Processing Laboratory Equipment List 1 of 8 4
B NSWS Blank Data Forms 1 of 19 4
C Examples of Calculations Required for ANC and
BNC Determinations 1 of 29 4
3.
3.
3.
3.
3.
3.
3.
3.
3.
3.
3.
3.
10.
10.
10.
10.
10.
10.
10.
10.
10.
10.
10.
10.
1
2
3
4
5
6
7
8
9
10
11
12
Scope and Application
Summary of Method
Interferences
Safety
Apparatus and Equipment
Reagents and Consumable Materials.
Sample Collection, Preservation,
and Storage
Calibration and Standardization. .
Quality Control
Procedure
Calculations
Precision and Accuracy
52
52
52
53
53
53
54
54
54
54
55
55
of
of
of
of
of
of
of
of
of
of
of
of
57
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57
57
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57
57
57
57
57
57
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Section Figures
Revision 4
Date: 9/87
Page 1 of 1
FIGURES
:igure Page Revision
1-1 Structure and timetable of the National
Surface Water Survey 2 of 9 4
2-1 Flow scheme of daily processing facility
activities for surface water samples 3 of 43 4
2-2 Field sample label 4 of 43 4
2-3 Aliquot and audit sample labels 6 of 43 4
2-4 NSWS Form 2, Batch/QC Field Data 7 of 43 4
2-5 MSWS Form 3, Shipping 10 of 43 4
2-6 Data flow scheme for NSWS Forms 1, 2, and 3 11 of 43 4
2-7 Flow scheme of daily processing facility activities
for snowpack samples 12 of 43 4
2-8 Schematic of FIA system for aluminum speciation ... 27 of 43 4
2-9 Schematic of FIA system for determination of total
nitrogen 40 of 43 4
3-1 Example HPLC chromatogram 46 of 57 4
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Section Tables
Revision 4
Date: 9/87
Page 1 of 1
TABLES
Table Page Revision
1-1 Required Minimum Analytical Detection Limits,
Expected Ranges, and Intralab Relative
Precision Goals 6 of 9 4
2-1 Sample Codes Used to Complete NSWS Form 2, Batch/QC
Field Data '. 8 of 43 4
2-2 Snowmelt Sample Measurement/Aliquot Priorities .... 14 of 43 4
2-3 Snowmelt Aliquots, Containers, and Preservatives ... 16 of 43 4
2-4 Precision and Accuracy for Single Operator/Single
Laboratory Analysis of Inorganic Monomeric A! by
FIA/PCV Method 33 of 43 4
2-5 Precision and Accuracy for Single Operator/Single
Laboratory Analysis of High Levels of Inorganic
Monomeric Al by FIA/PCV Method 33 of 43 4
2-6 Percent Recovery of Monomeric Al from Two Spiked
Natural Surface Water Samples Analyzed by the
FIA/PCV Method 34 of 43 4
3-1 Surface Water and Snowmelt Aliquots, Containers,
Preservatives, and Corresponding Parameters to be
Measured at the Analytical Laboratory 2 of 57 4
3-2 Sample Holding Times 3 of 57 4
3-3 Parameters and Corresponding Measurement Methods
Used by the Analytical Laboratory 4 of 57 4
3-4 Summary of Internal Method Quality Control Checks. . . 5 of 57 4
3-5 Maximum Control Limits for Quality Control Samples
Used in the Analytical Laboratory 7 of 57 4
3-6 Factors for Converting mg/L to peq/L 10 of 57 4
3-7 Chemical Reanalysis Criteria 10 of 57 4
3-8 Conductance Factors of Ions 12 of 57 4
3-9 Data Forms Used by the Analytical Laboratory 13 of 57 4
3-10 National Surface Water Survey Data Qualifiers 14 of 57 4
3-11 Calculation Procedures for Combinations of Initial Vi
and pH 35 of 57 4
3-12 Constants and Variable Descriptions 36 of 57 4
3-13 Dilutions of Chlorophyll a_ Stock Standard to. Make
Working Standards 48 of 57 4
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Section 1.0
Revision 4
Date: 9/87
Pace 1 of 9
1.0 INTRODUCTION
Data published in earlier studies are consistent with the hypothesis that
certain surface waters within the United States have decreased in pH, acid
neutralizing capacity (ANC), or both over time. Acidic deposition possibly
contributes to such decreases. The actual sensitivity of a lake or stream
to acidification depends on the ANC that is generated within both the body
of water itself and its associated watershed (Linthurst et al., 1986).
Attempts have been made to extrapolate local studies to a regional or
national scale to estimate quantitatively the risk to aquatic resources
from acidic deposition. These endeavors have achieved limited success
because of problems associated with (1) the comparability of the sampling
and analytical methodologies used, (2) the possibility of biased or non-
representative sampling sites, and (3) a small and incomplete data base.
The National Surface Water Survey (NSWS) is part of the National Acid
Precipitation Assessment Program (NAPAP), Task Group E (Aquatic Effects).
Divided into the National Lake Survey (NLS) and the National Stream
Survey (NSS), NSWS is designed to overcome some of the deficiencies of
earlier studies. NSWS is designed to evaluate the present water chemistry
of lakes and streams and to select regionally representative surface
waters for a long-term monitoring program.
1.1 BACKGROUND
Figure 1-1 shows how NSWS activities relate to each other. The first
NSWS lake survey was the Eastern Lake Survey - Phase I (ELS-I), a synoptic
survey of selected lakes in the southeastern, northeastern, and upper
midwestern regions of the United States. ELS-I was designed to provide a
chemical characterization of lakes based on a single sample collected from
each lake during fall overturn.
Planning for the Eastern Lake Survey - Phase II (ELS-II) began in October
1985. The conceptual approach to the program was developed by EPA personnel
and cooperating scientists. ELS-II has as its major objective a study of
the temporal variability of selected water-quality parameters. To assess
this temporal variability, a statistically representative subset of lakes
sampled during ELS-I will be sampled during ELS-I.I. The sampling and
analytical procedures that will be used during ELS-II are based on the
procedures that were used during ELS-I and are designed to produce data of
comparable quality.
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Section 1.0
Revision 4
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Page 2 of 9
National Surface Water Survey
(NSWS)
National Lake Survey (MLS)
Phase I - Synoptic Survey
Eastern Lake (1984)
Western Lake (1985)
National Stream Survey (NSS)
Phase I - Synoptic Survey
Pilot Survey (1985)
Synoptic Survey (1986)
Southeast Screening (1986)
Episodes Pilot (1986)
Phase II - Temporal Variability
Eastern Lake (1986)
Figure 1-1. Structure and timetable of the National Surface Water Survey.
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Section 1.0
Revision 4
Date: 9/87
Page 3 of 9
ELS-11 was designed to alleviate uncertainty in making temporal and
.regional assessments based on existing data by:
° providing temporal data from a subset of lakes that were sampled in
ELS-I and that are characteristic of the overall population of lakes
within a region.
° using standardized methods of sample collection and data collection.
° measuring a complete set of variables thought to influence or to be
influenced by surface-water acidification.
° providing data that can be used to quantify relationships among
chemical variables on a regional basis.
° providing reliable estimates of the chemical status of lakes within a
region.
ELS-II focuses on lakes that are considered most susceptible to acidic
deposition, those with an ANC of less than 400 ueq/L. Lake chemistry is
measured at least once during each of three consecutive seasons (seasonal
surveys). Additional sampling is conducted during the spring snowmelt
period to permit an evaluation of the severity of acidic episodes in lakes
(spring variability pilot study). The snowpack of some of the associated
watersheds also is sampled to determine the relationship between snowpack
conditions and acidic episodes in the lakes (snowpack pilot study). In
all, five subsurveys are contained in ELS-II: (1) spring variability, (2)
snowpack, (3) spring seasonal, (4) summer seasonal, and (5) fall seasonal.
1.2 SPRING VARIABILITY STUDY
The spring variability pilot study is designed to provide experience in
winter sampling techniques and to obtain data describing the spatial and
temporal variability of lake chemistry during snowmelt. Because of the
intensive sampling required and the difficult sampling conditions, only a
few lakes are included in this survey. For the same reasons, and because
the goals are specific and not directly related to the objectives of the
other ELS-II surveys, lake selection was based strongly on logistical
considerations and was not random.
The spring variability study includes four experiments: (1) comparing
the data obtained from two different types of in-situ monitoring devices;
(2) collecting samples and taking measurements from sites on transects and
from random sites wnen determining spatial variability in the littoral
zone and comparing results; (3) comparing two sampling protocols for
lakes that are thermally stratified; and (4) evaluating whether assistance
from a diaphragm pump improves the efficiency of sample collection with a
Van Dorn unit.
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Page 4 of 9
All the chemical variables that were measured during ELS-I are measured
during the spring variability study. Samples are collected from two lake
sites by the inlet, one lake site by the outlet, and four pelagic sites.
1.3 SEASONAL SURVEYS
The three seasonal surveys are conducted to identify annual and seasonal
variation and patterns in lake water chemical characteristics. All the
seasonal samples undergo the same analyses as samples from ELS-I did,
plus analysis for PCV-reactive aluminum. For each individual seasonal
survey, additional goals and concerns may apply and additional analyses
may be required; these survey-specific goals and analyses are described
in the following paragraphs. The samples are collected from the site
that was sampled during ELS-I, which is normally the deepest part of the
lake and normally the center of the lake. In this document, that site
is referred to as the fall index site.
1.3.1 Spring Seasonal Survey
For the spring seasonal survey, samples are collected immediately follow-
ing ice-out to provide an index of the lake chemical characteristics
during the spring overturn period before the onset of summer stratifi-
cation.
1.3.2 Summer Seasonal Survey
The summer seasonal survey is of special interest because it takes place
during the period of greatest spatial and temporal variability and of
highest pH in the lakes. In addition to the standard set of analyses,
dissolved oxygen is measured in situ, and total nitrogen and chlorophyll
£ are determined in the laboratory. A second total phosphorus determi-
nation is made for zooplankton counts. Special sample portions (anoxic
samples) are collected from the hypolimnion to determine if low levels
of dissolved oxygen affect the valencies and compounds of metals that
are present. Zooplankton tows are taken. A laboratory bias study is
being performed in conjunction with the summer survey; the two contract
analytical laboratories participating in the survey analyze splits of
the same sample so that any interlaboratory bias can be identified.
1.3.3 Fall Seasonal Survey
Besides its role as a component seasonal survey, the fall survey serves
as a means to assess the variability, or sampling error, associated with
the fall index sample taken during ELS-I. The degree of sampling error
determined will indicate the representativeness of the single ELS-I
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Section 1.0
Revision 4
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Pago 5 of 9
sample as a measure of conditions in the lake during the fall overturn
period.
The U.S. Environmental Protection Agency (EPA) requires a program of
data collection activities which ensures that the resulting data are of
known quality and are suitable for their intended purpose. ELS-II was
designed to provide statistically comparable data that could be extra-
polated, with a known degree of confidence, to a regional or national
scale. The conceptual approach emphasized that the data would not be
used to ascribe observed effects to acidic deposition phenomena; rather,
through comprehensive monitoring activities, ELS-II will provide infor-
mation that can be used to develop correlative, not cause-and-effect,
relationships.
This manual provides details of and references to the analytical methods
and internal quality control (QC) used to process and analyze ELS-II
samples. Details of the actual sampling methods and the on-site lake
analyses are provided in the ELS-II field operations report (Merritt et
al.', 1988). External and internal QA and QC activities are discussed in
detail in the ELS-II QA plan (Engels et al., 1986). Sample handling,
including the processing of samples from special studies, is described
in the ELS-II Laboratory Operations Report (Arent et al., 1988).
1.4 ANALYTES AND PHYSICAL PARAMETERS MEASURED
The constituents and parameters to be measured are described in Sections
1.4.1 through 1.4.17. Table 1-1 lists the required analytical detection
limits, expected ranges, and relative precision goals.
1.4.1 Acid Neutralizing Capacity
ANC is the alkalinity of a system that is based on the carbonate-ion
system. The soluble species are H2C03, HC03~, and C03^~. Acidic depo-
sition in lake waters would alter the equilibrium among these ions. The
calculations assume that the lakes in this survey are represented by a
carbonate-ion system; the ANC definition is in the context of that
system.
1.4.2 Aluminum. Nonexchangeable PCV-Reactive
Nonexchangeable PCV-reactive aluminum is a measure of the amount of
aluminum that is not retained by cation-exchange resin but that forms a
complex with pyrocatechol violet (PCV). This fraction consists
primarily of organic aluminum complexes. Nonexchangeable PCV-reactive
aluminum is an estimate of the portion of total PCV-reactive aluminum
that is not biologically active. The toxicity of aluminum and its
increased solubility under acidic conditions are major concerns of
acidic deposition studies.
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Section 1.0
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Paqe 6 of 9
TABLE 1-1. REQUIRED MINIMUM ANALYTICAL DETECTION LIMITS, EXPECTED RANGES,
AND INTRALAB RELATIVE PRECISION GOALS
Aci
Parametera
d neutralizing
Units
Meq/L
Required
Detection
Limit
5
Expected
Range
-100-1,000
Intralab Relative
Precision Goal (%'.
10
|b
capacity (ANC)
Aluminum, nonexchangeable
reactive
Aluminum, total
Aluminum, total
extractable
Aluminum, total PCV-
reacti ve
Ammonium, dissolved
Base neutralizing
capacity (BNC)
Calcium, dissolved
Chloride, dissolved
Chlorophyll a
Fluoride, total dissol
Inorganic carbon,
dissolved
Iron, dissolved
Magnesium, dissolved
Manganese, dissolved
Nitrate, dissolved
Nitrogen, total
Organic carbon, dissol
pH, field
pH, laboratory
Phosphorus, total
Potassium, dissolved
Silica, dissolved
Sodium, dissolved
Specific conductance
Sulfate, dissolved
True color
Turbidity
mg/L
mg/L
mg/L
mg/L
mg/L
ueq/L
mg/L
mg/L
-
ved mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
ved mg/L
pH units
pH units
mg/L
mg/L
mg/L
mg/L
uS/cm
mg/L
PCUe
NTUf
0.01
0.005
0.005
0.01
0.01
5
0.01
0.01
-
0.005
0.05
0.01
0.01
0.01
0.005
0.007
0.1
-
-
0.002
0.01
0.05
0.01
d
0.05
0
2
0.01-0.50
0.005-1.0
0.005-1.0
0.01-0.50
0.01-2
10-150
0.5-20
0.2-10
-
0.01-0.2
0.05-15
0.01-5
0.1-7
0.01-5
0.01-5
0.01-20
0.1-50
3-8
3-8
0.005-0.07
0.1-1
2-25
0.5-7
5-1,000
1-20
0-200
2-15'
10
10(A1>0.01),20{A1<0.01)
10(Al>O.Ql),20(Al0.01),20(P<0.01)
5
5
5
1
5
±5C
10
Dissolved ions and metals are being determined, except where noted.
^Unless otherwise noted, this is the relative precision at concentrations
above 10 times instrumental detection limits.
cAbsolute precision goal is in terms of applicable units.
d31ank must be <0.9 ^iS/cm.
ePCU = platinum-cobalt units (APHA, 1985; EPA, 1983).
= nephelometric turbidity units.
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Section 1.0
Revision 4
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Page 7 of 9
1.4.3 Aluminum, Total
Total aluminum is an estimate of the aluminum pool potentially available
to the biological environment.
1.4.4 Aluminum, Total Extractable
Total extractable aluminum is a component of dissolved aluminum and
includes most mononuclear aluminum species. Aluminum in certain forms
is considered to be highly toxic, especially to fish. Knowing its
concentration is important in assessing the biological environment of a
lake.
1.4.5 Aluminum. Total PCV-Reactive
Total PCV-reactive aluminum is a component of dissolved aluminum and
includes most mononuclear aluminum species. The method used measures
the total amount of monomeric aluminum that can be complexed by PCV.
This factor is important in estimating the available amount of acutely
toxic aluminum. Measuring total PCV-reactive aluminum and total extract-
able aluminum will help determine the relationship between the two
components.
1.4.6 Base Neutralizing Capacity
The base neutralizing capacity (BMC) is the acidity of a system that is_
based oo the carbonate-ion system. The soluble species are H^CO^, HCC>3 ,
and CO-,'". Acidic deposition in lake waters alters the equilibrium
among these ions. The calculations assume that the lakes in this survey
are represented by the carbonate-ion system; the BNC definition is in
the context of that system.
1.4.7 Chlorophyll a
Chlorophyll a_ is an indicator of the algal biomass and standing crop
and is related to the primary productivity of a lake.
1.4.8 Inorganic Carbon, Dissolved
The preliminary determination of dissolved inorganic carbon (DIC) is
useful in determining whether a lake is saturated with dissolved CO;?.
The preliminary determinations and the contract analytical laboratory
determinations of DIC (when evaluated in combination with pH measure-
ments) are useful in QA/QC calculations.
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Section 1.0
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Page 3 of 9
1.4.9 Ions. Dissolved (Ca, C1", F", Fe. K, Mg, Mn, Na, NH/. MO^", and SO^2")
Dissolved ions are determined so that the lake can be characterized
chemically, especially for mass ion balance and buffering capacity.
Fluoride is also important as a natural chelator of aluminum.
1.4.10 Nitrogen. Total
Total nitrogen is an indicator of the biological status of lake water.
1.4.11 Organic Carbon, Dissolved
Dissolved organic carbon (DOC) determination is necessary to establish
a relationship between the organic carbon content and the true color of
the lake water. Also, DOC can be important as a natural chelator of
aluminum.
1.4.12 pH_
The pH is a general and direct indication of free hydrogen ion concen-
tration. Acidic deposition can increase this concentration.
1.4.13 Phosphorus, Total
Total phosphorus is an indicator of overall trophic status and of
potentially available nutrients for phytoplankton productivity.
1.4.14 Silica, Dissolved
The absence or existence of dissolved silica (Si02) is an important
factor controlling diatom blooms; the determination also assists in
identifying trophic status. Dissolved silica is also an indication of
mineral weathering.
1.4.15 Specific Conductance
The conductance of lake water is a general indication of its ionic
strength and is related to buffering capacity. Dissolved ions (either
hydrogen or others dissolved due to the presence of hydrogen ions) will
increase the ionic strength of lake waters.
1.4.16 True Color
True color is an indicator of natural 3NC and DOC. Substances that
impart color also may be important natural chelators of aluminum and of
other trace elements. Color is measured in platinum-cobalt units
(PCUs; APHA et al., 1985).
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Section 1.0
Revision 4
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Paao 9 of 9
1.4.17 Turbidity
Turbidity is a measure of suspended material in lake water and is
measured in nephelometric turbidity units (NTUs).
1.5 REFERENCES
American Public Health Association, American Water Works Association, and
Water Pollution Control Federation, 1985. Standard Methods for the
Examination of Water and Wastewater, 16th Ed., APHA, Washington,
D.C., pp. 60-70.
Arent, L. J., M. 0. Morison, and C. S. Soong, 1988. Eastern Lake Survey -
Phase II and National Stream Survey - Phase I Processing Laboratory
Operations Report. EPA 600/4-88/025. U.S. Environmental Protection
Agency, Las Vegas, NV.
Engels, J. L., T. E. Mitchell-Hall, S. K. Drouse, M. D. Best, and D. C.
McDonald. (In press). National Surface Water Survey, Eastern Lake
Survey (Phase II — Temporal Variability) Quality Assurance Plan
(In press). U.S. Environmental Protection Agency, Las Vegas, Nevada.
Linthurst, R. A., D. H. Landers, J. M. Eilers, D. F. Brakke, W. S. Overton,
E. P. Meier and R. E. Crowe, 1986. Characteristics of Lakes in the
Eastern United States, Volume 1: Population Descriptions and Physico-
Chemical Relationships. EPA 600/4-86/007a, U. S. Environmental
Protection Agency, Las Vegas, NV.
Merritt, G. D., and V. A. Sheppe, 1988. Eastern Lake Survey - Phase II
Field Operations Report. EPA 600/4-88/024. U.S. Environmental
Protection Agency, Las Vegas, NV.
U.S. Environmental Protection Agency, 1983 (revised). Methods for
Chemical Analysis of Water and Wastes. EPA-600/4-79-020. U.S. EPA,
Cincinnati, Ohio.
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Section
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Section k.u
Revi sion 4
Date: y/b/
Page e. of 43
Following sample arrival, surface water samples and snowpack samples
are processed, determinations are made, ana samples are shipped to tne
analytical laboratories. Because the procedures used to process tne two
types of samples differ, activities related specifically to surface water
samples (Section 2.3) and activities related specifically to snowpack
samples (Section 2.4) are discussed separately.
2.3 PROCEDURES FOR PROCESSING SURFACE WATER SAMPLES
After surface water samples are delivered to the processing facility, tne
steps outlined in Figure 2-1 are performed. First, the coordinator,
organizes the samples into a batch. Next, the supervisor and the analyst
prepare aliquots and make pH, turbidity, DIC, true color, nonexchangeaDle
reactive aluminum, and total PCV-reactive aluminum determinations. The
analysts also prepare chlorophyll a samples. After all processing functions
and determinations are finished, tFe data forms are completed, the samples
are packed, and the forms and samples are shipped to their destinations.
2.3.1 Sample Identification and Batch Organization
Five types of surface water samples are processed by the processing
laboratory. Blank samples and routine samples are received from field
sampling crews; field audits are prepared at and shipped from a central
source; and laboratory audits and laboratory duplicates originate at the
processing laboratory. Upon receipt, the sample type can be determined
from the field sample label (Figure 2-2). Each day's samples are
organized into a batch that includes all the routine, duplicate, field
audit, and blank samples for that day, as well as the laboratory audit
samples (inserted daily at the processing facility).
After the batch is organized, a unique batch ID number is assigned and
is recorded on the sample labels (and corresponding aliquot labels) of
all samples in the batch. An ID number is assigned randomly to each
sample in the batch as follows:
° Routine Samples—Five sample containers are filled at each sampling
location: two syringes for DIC and pH determination, two syringes
for monomeric aluminum analyses, and one Cubitainer. One ID number
is assigned to all five containers and is recorded on each container
label.
° Duplicate and Blank Samples—ID numoers are assigned according to the
same procedure used for the routine samples.
NOTE: There are no syringe samples for the blank.
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Section
Revision
Liate:
Page J of 4J
Before Sample Arrival
1. Prepare reagents for
a) Total extractable Al
b) Reactive AT
c) DIG
d) pH
2. Warm up and calibrate instruments
a) Turbidimeter
b) Carbon analyzer
c) pH meter
d) Flow-injection
analyzer
e) Nephelometer
Sample Arrival
Following Sample Arrival
Insert required audit samples, assign
batch and ID numbers, start batch form
Prepare aliquots
Determine DIG
Determine nonexchangeable PCV-reactive
and total PCV-reactive Al
Determine pH
Determine turbidity
Determine true color
Prepare chlorophyll a samples
Complete batch and shipping forms
Ship samples
Distribute data
Figure 2-1. Flow scheme of daily processing facility activities
for surface water samples.
-------
Section <^.
Revision 4
•Jate:
Page 4 of
Sample Location
Crew ID
Date
Sampled
Time
Sampled
Sample Type (Check One)
Routine
Duplicate
Blank
Batch ID
Sample ID
Figure 2-2. Field sample label.
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Section z.u
Revision 4
Date: y/8?
Page 5 or 4J
° Field Audit Samples—One 2-L field audit sample (received eacn uay
from a central source) is inserted into eacn day's oaten of samples at
the processing facility. The field audit sample is assigned an 10
number according to the same procedure used for a routine sample, and
the number is recorded on the field audit sample label (Figure 2-3a).
'° Lab Audit Samples—One lab audit sample (received from a central
source) is included in each day's batch. A single lab audit sample
consists of a set of seven aliquots. Each aliquot has a temporary
label (Figure 2-3b) that lists the aliquot number, audit sample code,
preservative amount, and shipping and receiving date.s. The lab audit
sample is then assigned batch and sample ID numbers according to the
same procedure used for a routine sample. An aliquot laoel (Figure
2-3c) is attached to each aliquot, and the batch and sample ID numbers
are recorded on the label, as are the date and amount of preservative
added. Lab audit samples receive no processing other than labeling
and shipping.
After the batch and sample ID numbers have been assigned and have been
recorded on each sample label, the same information is recorded on
NSWS Form 2, Batch/QC Field Data (Figure 2-4). After Form 2 is
completed, the temporary label on the lab audit sample is removed and
placed in the lab audit logbook. Codes necessary to complete the form
are given in Table 2-1.
NOTE 1: Seven aliquots are prepared from each field sample (routine,
duplicate, or DlanK). Each aliquot is assigned the same
batch and ID number as the sample from which it is prepared.
2.3.2 Aliquot Preparation
Seven aliquots are prepared from each sample, each with the same batch
and sample ID numbers. The details for preparing eacn aliquot are
provided in Hi 11 man et al. (1986).
2.3.3 Determination of Analytes and Physical Parameters
For surface water samples, the analytes and physical parameters that
are determined at the processing facility include DIG (Section 2.6),
pH (Section 2.6), true color (Section 2.7), turbidity (Section 2.8),
and PCV-reactive aluminum [total and nonexchangeable (Section 2.9)j.
2.3.4 Form Completion, Sample Shipment, and Data Distribution
After a batch has been completely processed, the supervisor records^
all analytical data on the Batch/QC Field Data Form (Figure 2-4). The
coordinator then reviews and signs the form. Next, each aliquot is
-------
Section <^.U
Revi sion 4
Date: y/
-------
Section 2.0
Revision 4
Date: 9/87
Page 7 of 43
NATIONAL SURFACE WATER SURVEY
FORM 2
BATCH/QC FIELD DATA
OATE RECEIVED
3Y OArA WOT
ENTERED
BE ENTERED
LAB TO WHICH
3ATCHSENT _
NO SAMPLES
IN BATCH
DATE SHIPPED
LAB CREW 10
DATE PROCESSED
AIH.BILL NO ._
FIELD LABORATORY
SUPERVISOR
FIELD
CREW
10
LAKE
10
(XXX-XXX)
SAMPLE
CODE
DIC (mg/L)
OCCS LIMITS
UCL - 2.2
LCL - 1.1
'VALUE Foccs
STATION pH
OCCS LIMITS
UCL - «.1
LCL - 3.»
TURBIDITY (NTU)
OCCS LIMITS
UCL - 5.5
LCL — <.5
1
COLOR I SPLIT
(APHA 1 CODES
UNITS) I (E.L)
I VALUE |~QCCS i VALUE I OCCS I VALUE
I r°
COMMENTS
Figure 2-4. NSWS Form 2, Batch/QC Field Data.
-------
Section 2.0
Revision 4
Date: ^/d7
Page a or 4J
TABLE 2-1. SAMPLE CODES USED TO COMPLETE NSWS FORM 2, BATCH/qC FIELD DATA
Sample Type
Code
Description
Normal
R
D
B
TD
Routine Lake Sample
Duplicate Lake Sample
Field Blank Sample
Laboratory Duplicate
Audit
F L X-X
Radian ID Number
Concentrate Lot Number
Concentration Level
(L = low, N = natural)
Type of Audit Sample .
/F = field audit sample]
IL = lab audit sample J
Aliquot 1
for Penn State3
A volume of aliquot 1 (of snowmelt
only) is sent to the Pennsylvania State
University laboratory.
The aliquot has the same batch and
sample ID numbers as assigned in Section
2.4. However, for the Penn State sample,
the letter P is recorded under the Split
Code column on Form 2.
aSnowmelt only. See Section 2.4 for explanation of .snowpack sample preparation.
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Section 2.0
Revision 4
Date: 9/87
Page 9 of 43
sealed in a plastic bag and is packed in a Styrofoam-lined shipping con-
tainer, along with 7 to 10 frozen freeze-gel packs (to maintain aliquots
at 4 °C). A shipping form (NSWS Form 3, Figure 2-5) is completed and is
enclosed with each container. The container is shipped by overnight
delivery to its destination. Finally, copies of Forms 1 (a form
completed by the sampling crew for each sample), 2, and 3 are sent to
the locations indicated in Figure 2-6.
2.4 PROCEDURES FOR PROCESSING SNOWPACK SAMPLES
For snowpack samples, a processing procedure similar to the one for
surface water samples is followed (Figure 2-7). Snowpack samples, however,
are melted at ambient temperature before they are processed, and the only
measurements performed on the snowmelt are DIC and pH. In addition, only
aliquots 1, 3, 4, and 5 are prepared from snowmelt, and the volumes pre-
pared are different from the volumes prepared for aliquots of surface water
samples. Sections 2.4.1 through 2.4.5 describe differences between snowpack
sample processing and surface water sample processing.
2.4.1 Sample Identification and Batch Organization
Sample identification and batch organization procedures for snowpack
samples are identical to procedures for surface water samples, with the
following exceptions:
0 Routine Samples—Routine snowpack samples are received in sealed
plastic buckets.
° Duplicate and Blank Samples—Blank water samples accompany each batch .
and should be treated in the same manner as the snowpack samples they
accompany. In particular, it is important that the blank water samples
are exposed to the complete melting process along with the snowpack
samples.
° Additional Aliquots--When there is sufficient sample volume, an addi-
tional aliquot 1 is prepared and is sent to the Pennsylvania State
University laboratory for analysis of trace metals.
2.4.2 Sample Preparation
2.4.2.1 Summary of Method—
Snowpack samples are received in sealed plastic buckets. The samples
are melted at room temperature, the buckets are opened, the melted
snow is poured into a Cubitainer, and the snowmelt is subjected to
selected portions of the surface water sample processing procedure.
DIC and pH are determined at the mobile processing facility, and
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Section 2.0
Revision 4
Date: 9/87
Page 10 of 43
NATIONAL SURFACE WATER SURVEY
SAMPLE MANAGEMENT OFFICE
PO. BOX 818
ALEXANDRIA. VA 22314
NSWS
FORM 3
SHIPPING
RECEIVED BY
IF INCOMPLETE IMMEDIATELY NOTIFY-
SAMPLE MANAGEMENT OFFICE
1703) 557-2490
-ALIFIERS
v ALIQUOT SHIPDPQ
y ALIQUOT WISSING DUE TO DESTROYED SAMPLE
- = OU
S'ATlCNIOl 1 .ABl
I
iAMPLE
3'
BATCH
•0
3ATE °ROCESSED
AL.QUOTS SHIPPED
?OR NATION USE ONLYi
-.2 \
J3 1
.'•> 1
"5
:s 1
07 |
•;8
09
to
1 1
12
13
T4
'5
! '6
..
•8
•9
20
21
22
23
24
25
26
1 "
28
:9
^
~-
a
5
i
1
D
1
1
1
1
I
1
1
1
30
1
',
1
|
1
;
SPL
;ATE SHIPPED DATE =£CE-.E3 1
Alfl-BILL HG
I
T5
SAMPLE CONDITION UPON LA8 BECEIPr
FOR LAB USE ONLYI
Figure 2-5. NSWS Form 3, Shipping.
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Section 2.0
Revision 4
Date: 9/87
Page 11 or 43
ANALYTICAL
LABORATORY
Form 3 (1 copy)
horm 3 (2 copies)
SAMPLE
MANAGEMENT
OFFICE
QA
MANAGER
DATA
BASE
MANAGER
Form 3
PROCESSING
FACILITY
(keeps 1 copy
of Forms 1,
2, and 3)
Forms 1 and 2
Forms 1 and 2
Figure 2-6. Data flow scheme for NSWS Forms 1, 2, and 3.
-------
Section ^.U
Revision 4
Date: ^/87
Page i',i of 43
Before Sample Arrival
Prepare reagents for
a) DIG
b) pH
Warm up and calibrate
a) Carbon analyzer
b) pH meter
Sample Arrival
Following Sample Arrival
1.
1. Insert required audit samples, assign batch and ID
numbers, start batch form
2. Melt snowpack samples
3. Prepare aliquots 1, 3, 4, 5
4. Determine DIG
5. Determine pH
6. Prepare aliquot for Pennsylvania State University
7. Complete batch and shipping forms
8. Ship samples
Distribute data
Figure 2-7. Flow scheme of daily processing facility activities
for snowpack samples.
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Section
Revi si on
Date:
Page 13 of 4J
aliquots 1 (125 ml), 3 (125 ml), 4 (125 ml), and 5 (250 ITIL) are pre-
pared from the snowmelt (see Section 2.4.3). An additional volume of
aliquot 1 is sent to Pennsylvania State University. Volume permitting,
duplicate pH and DIG measurements are made.
Bulk precipitation samples received may contain insufficient snow for
analysis; if the volume of the snowmelt is less than 60 ml, 1.00 - of
Type I water (ASTM, 1984) is added. If the volume is above 60 ml, the
following measurements and aliquot preparations are performed (listed
in order of priority): pH, DIG, aliquot 5, aliquot 3, aliquot 1, aliquot
4, aliquot 1 for Pennsylvania State University, duplicate pH, and
duplicate DIG.
In addition to snowpack samples, blank water samples are shipped witn
each batch. The water samples should undergo the same treatment as
the snowmelt samples.
2.4.2.2 Safety—
The procedures in this section pose no special hazards to the analyst.
Follow the safety guidelines for each procedure used on the snowmelt
samples.
2.4.2.3 Apparatus and Equipment--
» Racks for Melting the Samples—Racks should be constructed to allow
maximum heat exchange with the air and should allow sample buckets
to contact only inert materials.
° Syringes (60-mL, plastic).
e Syringe Valves (Luer-Lok).
2.4.2.4 Reagents and Consumable Materials--
° Watei—Water used to increase the volume of snowmelt must meet the
specifications given in ASTM D 1193 (ASTM, 1984) for Type I reagent
water.
2.4.2.5 Procedure--
0 Melting the Snowpack Samples—After snowpack samples arrive at the
processing laboratory, the coordinator labels them and organizes
them into batches. Notation is made of all leaks from sample
buckets and of partial melting. The internal- temperature of the
cooler in which samples were shipped is measured and noted. The
mass of the sample and bucket together (measured at the sampling
site) is noted for each sample. If frozen freeze-gel packs broKe
during shipment, notation is made, and the exterior of the sample
bucket is washed with tap water. Using a polypropylene funnel,
samples and blanks are poured into Cubitainers. Samples are
processed only after the snow is completely melted; the melting
process usually requires between 14 and 30 hours.
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Section 2.J
Revision t
Date: 9/o7
Page 14 of 4J
The buckets containing the snowpack samples are placea on racks so
that they are in contact with inert materials only. The accompany-
ing blank water samples are placed atop frozen freeze-gel packs on
tne same racks. The olanks ana snowpack samples must be exposea to
exactly the same conditions.
The complete batch, including blanks and audit samples, must be
processed on the same day. If a complete batch is nearly melted but
cannot be processed that day, all of the samples and the blank are
refrigerated (4 °C). Upon removal from the refrigerator the next
day, the snowmelt samples are processed according to the same proce-
dures used for surface water samples (for pH and OIC determinations
and for aliquots 1, 3, 4, and 5). Note that smaller volumes of each
aliquot are prepared than are prepared from surface water samples.
Bulk Precipitation Samples—Upon arrival of bulk precipitation
samples, the coordinator organizes them into batches. The samples
and accompanying blanks are labeled and are placed on racks to melt
as above. If a sample does not have a snowmelt volume of 6U mL,
1.000 L of Type I water (ASTM, 1984) is added, and all surfaces of
the container are rinsed. For each sample that contains between 60
and 1,000 ml of snowmelt, aliquots are prepared and measurements are
made according to the priorities listed in Table 2-2. Snowmelt
volume can be estimated by measuring the depth of the liquid within
the bucket.
TABLE 2-2. SNOWMELT SAMPLE MEASUREMENT/ALIQUOT PRIORITIES
Priority Measurement/Aliquot Approx. vol. mLa
1
2
3
4
5
6
7
0
9
PH
OIC
Al iquot 5
Aliquot 3
Aliquot 1
Aliquot 4
Aliquot 1 for Pennsylvania
State University
Duplicate pH
Duplicate OIC
50
30
300
150
150
150
300
bU
60
Approximate total volume for container rinse and aliquot.
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Section 2.0
Revi sion 4
Date: 9/87
Page 15 of 43
° Handling the Snowmelt—Sealed buckets are placed on snowmelt racks
for melting. Buckets are shaken to determine when the melting proc-
ess is completed. After the melting process is completed, two 50-mL
centrifuge tubes are filled for pH measurement and one 30-mL syringe
is filled for DIG determination. Caution should be taken to minimize
exposure of the bucket contents to the air. Using a funnel which
has been rinsed twice with 10-mL aliquots of Type I water (ASTM,
1984) and finally with approximately 10 mL of sample, the remainder
of the snowmelt is poured quiescently into a Cubitainer. Solid
matter (leaves, twigs, etc.) should be retained in the bucket. The
Cubitainer is not collapsed to eliminate headspace. The Cubitainer
contents are handled as described in Section 2.4.3. For each sample
in the batch that contains sufficient volume of snowmelt, an addi-
tional volume of aliquot 1 is prepared for Pennsylvania State
University, one 60-mL syringe is filled for duplicate pH measure-
ment, and one 60-mL syringe is filled for duplicate DIG determi-
nation. The additional aliquot 1 and the duplicates, however, are
of a lower priority than is the preparation of the four primary
aliquots (see Table 2-2).
2.4.3 Aliquot Preparation
This procedure for snowmelt aliquot preparation is a modification of the
procedure used for surface water samples during ELS-I.
2.4.3.1 Summary of Method--
From each snowmelt sample, four aliquots (1, 3, 4, and 5) are prepared.
Each aliquot is processed in a different manner, according to which
analytes will be determined in the aliquot. All aliquots of the same
sample have the same batch ID number and the same sample ID number. A
brief description of the four aliquots prepared from snowmelt samples
is given in Table 2-3.
An additional volume of aliquot 1 is prepared for Pennsylvania State
University. This aliquot is handled according to the procedures given
for surface water split samples in Hi 11 man et al. (1986).
2.4.3.2 Safety—
The sample types and most reagents used in preparing aliquots do not
pose a hazard to the analyst. Protective clothing (lab coat, gloves,
and safety glasses) must be used when handling concentrated sulfuric
and nitric acids.
2.4.3.3 Apparatus and Equipment--
° Filtration Apparatus—This equipment includes a filter holder, vacuum
chamber, and vacuum pump.
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Section t.O
Revi sion 4
Date: 9/67
Page 16 of 43
TABLE 2-3. SMOWMELT ALIQUOTS, CONTAINERS, AND PRESERVATIVES
Aliquot
Container Description
Description
125 ml
(acid-washed)
Filtered sample acidified with HN03 to
pH <2
125 ml
(not acid-washed)
Filtered sample
125 mL
(acid-washed)
Filtered sample acidified with H2S04
to pH <2
250 mL
(not acid-washed)
Raw, unfiltered sample
2.4.3.4 Reagents and Consumable Materials--
° Nitric Acid (HN03, 12 M, Baker Ultrex grade or equivalent).
° Sulfuric Acid (^04, 18 M, Baker Ultrex grade or equivalent).
° Water—At the point of use, water used in all preparations must con-
form to ASTM specifications for Type I reagent water (ASTM, 1984).
8 Aliquot Bottles—Clean aliquot bottles are required for the four
aliquots prepared from each sample (see Table 2-3). The bottles
are cleaned (using the procedure described in Hillman et al., 1986)
and are supplied by an outside contractor.
° Indicating pH Paper (Range 8.0 to 9.0 and 1.0 to 3.0).
8 Membrane Filters (Millipore/Gelman GN-6 0.45-um pore size).
2.4.3.5 Procedure--
Preparation of the four aliquots is described in this section. All
filtrations are performed in the work station under a laminar-flow
hood.
Preparation of Aliquots 1 and 4
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Section 2.U
Revision 4
Date: y/a/
Pacje 17 of 43
Step I—Complete aliquot labels for aliquots 1 and 4 and attach
labels to containers. A 125-mL, acid-washed container is used for
each aliquot. Assemble the filtration apparatus; use a waste
container as a collection vessel. Thoroughly rinse the filter
holder and membrane filter in succession with 20 to 40 ml water,
20 ml 5 percent HN03 (Baker Instra-Analyzed grade or equivalent),
and 40 to 50 ml water.
Step 2--Rinse the filter holder and membrane with 10 to 15 ml of the
sample to be filtered.
Step 3--Replace the waste container with the aliquot 1 container.
Reapply vacuum (vacuum pressure must not exceed 12 in. Hg), and
filter 10 to 15 ml sample. Remove the vacuum. Rinse the aliquot 1
container with the filtrate by slowly rotating the oottle so that
the sample touches all surfaces. Discard the rinse sample and
place the container under the filter holder.
Step 4--Fi1ter sample into the container until full.
Step 5--Rinse the container with 10 to 15 mL filtered sample (as
described in Step 3), then transfer the filtered sample to the
aliquot 4 container (previously labeled).
Step 6—Return the aliquot 1 container to the filtration apparatus
and collect additional filtered sample until the container is full.
If it is necessary to replace a membrane (due to clogging) before
adequate filtered sample has been obtained, rinse the new membrane
in succession with 15 to 20 mL water, 10 to 15 mL 5 percent HN03, 40
to 50 mL water, and 10 to 15 mL sample prior to collecting additional
sample.
Step 7--Between samples, remove the membrane and thoroughly rinse
the filter holder with water.
Step 8—Preserve sample by adding concentrated HN03 to aliquot i and
concentrated H^SO^ to aliquot 4 in 0.100-mL increments until tne pH
is less than 2 (U.S. EPA, 1983).
Step 9~Check the pH by placing a drop of sample on indicating pH
paper using a clean, plastic pipet tip. 'Record on the aliquot label
the volume of acid added.
Step 10--Store aliquots 1 and 4 at 4 °C until ready to ship.
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° Preparation of Aliquot 3
Filtered sample for aliquot 3 is obtained similarly to that for
aliquots 1 and 4, except that the filter holder used to filter
aliquot 3 is NEVER allowed to come into contact with nitric acid.
This is CRUCIAL in preventing nitrate contamination.
Step l--Soak filter holders for 24 hours in deionized water prior to
first use.
Step 2—Complete an aliquot 3 label and attach label to the aliquot
bottle. Aliquot 3 is contained in a 125-mL, acid-washed container
(Table 2-3). Assemble the filtration apparatus witn a waste con-
tainer as a collection vessel. Thoroughly rinse the filter holder
and membrane filter with three 25-mL portions water, followed by 10
to 15 ml sample to be filtered.
Step 3—Replace the waste container with the aliquot 3 container
and filter an additional 15-mL sample. Remove the container and
rinse by slowly rotating the bottle so that the sample touches all
surfaces. Discard the rinse sample and place the container under
the filter holder.
Step 4—Filter sample into the container until full.
If it is necessary to replace a membrane (due to clogging), rinse
the membrane with three 20-mL portions water followed by 15 ml
sample before collecting additional sample.
Step 5~Between samples, remove the membrane and thoroughly rinse
the filter holder with water.
Step 6--Store at 4 °C until ready to ship.
• Preparation of Aliquot 5
Aliquot 5 is an unfiltered aliquot.
Step I—Complete aliquot 5 labels and attach them to the appropriate
aliquot bottles. Aliquot 5 is prepared in a 250-mL container (not
acid-washed; Table 2-3). Transfer 15 to .20 mL sample to aliquot
bottle and rinse by slowly rotating bottle so that sample touches
all surfaces. Discard rinse.
Step 2—Fill aliquot bottle with unfiltered sample. Fill oottle so
that no headspace exists.
Step 3--Store at 4 °C until ready to ship.
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2.4.4 Determination of Analytes and Physical Parameters
At the processing facility, only QIC and pH are determined for snowpack
samples. DIG is determined as described in Section 2.5, and pH is
determined as described in Section 2.6. Both methods follow the proce-
dures that were used for surface water samples during ELS-I (Hi 11 man et
al., 1986).
2.4.5 Forms Completion. Sample Shipment, and Data Distribution
These procedures are identical to the procedures used for surface water
samples (Section 2.3.4) except that appropriate procedures must also be
followed for aliquot 1 samples sent to Pennsylvania State University.
Aliquots to be sent to Pennsylvania State University are designated with
a "P" in the split code column on NSWS Form 2 (see Figure 2-4 and Table
2-1).
2.5 DETERMINATION OF DIG
The DIG determination, which is applied to surface water samples and to
snowpack samples, uses the procedure from ELS-I (Hillman et al., 1986).
2.6 DETERMINATION OF pH
The pH measurement, which is applied to surface water samples and to snow-
pack samples, uses the procedure from ELS-I (Hillman et al., 1986).
2.7 DETERMINATION OF TRUE COLOR
The color determination, which is applied to surface water samples but not
to snowpack samples, uses the procedure from ELS-I (Hillman et al., 1986).
2.8 DETERMINATION OF TURBIDITY
The turbidity determination, which is applied to surface water samples but
not to snowpack samples, uses the procedure from ELS-I (Hillman et al.,
1986).
2.9 FRACTIONATION AND DETERMINATION OF ALUMINUM SPECIES
2.9.1 Scope and Application
This method is a semi-automated colorimetric method applicable to the
determination of reactive aluminum in natural surface waters. In
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aqueous samples, the method colorimetrically measures the amount of
aluminum which forms a complex with pyrocatechol violet (PCV). The
measurement is performed on two sample streams, one directly and one
after passage through a cation-exchange column.
For purposes of this analysis, reactive aluminum is defined as the
fraction of soluble (dissolved) aluminum that reacts with PCV without
preliminary acidification. This fraction is believed to represent tne
monomeric portion of the total aluminum pool. This includes free inor-
ganic monomeric aluminum, various aluminum hydrous oxides, and aluminum
bound to various inorganic and organic ligands. The reactivity of cer-
tain aluminum complexes depends on the strength (stability constant) of
the complex in relation to the aluminum-PCY complex.
Total reactive aluminum is defined as the fraction of the total dis-
solved aluminum pool that forms a complex with PCV. Dissolved species
are species that pass through a 0.45-um filter. It is known that some
particulate forms of aluminum are smaller than 0.45 urn. These forms
include sols, colloidal aluminum complexes (monomeric and polymeric),
and clay minerals. The reactivity of these complexes with PCY is
unknown.
Reactive nonexchangeable aluminum is defined as the fraction of total
reactive aluminum that is not removed from the sample stream after
passage through the cation-exchange column. This fraction consists
primarily of organic-aluminum complexes. The stability constants of
these complexes are greater than the affinity of the cation-exchange
column for the bound aluminum, yet are less than the stability constant
for the aluminum-PCV complex. This fraction is theoretically nontoxic
to fish, at least in terms of acute effects.
Toxic aluminum is not measured directly but can be estimated by sub-
tracting reactive nonexchangeable aluminum from total reactive aluminum.
This difference extimates the amount of inorganic monomeric aluminum
which is believed to manifest acute toxic responses in fish.
The method detection limit (MDL) has been determined to be 7.U ug Al/L
for repetitive measurements of a low aluminum standard.
The method as presented here does not distinguish between various in-
organic monomeric aluminum species, nor does it distinguish between the
various neutral organic complexes of aluminum. Furthermore, the
definitions of total reactive and nonexchangeable reactive aluminum are
based on commonly accepted usage. In actuality, some charged or weakly
bound organic-aluminum complexes will be removed by the cation exchange
column and are regarded as inorganic monomeric species, and some strongly
complexed monomeric aluminum may not be measured in either fraction.
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2.9.2 Summary of Method
Samples are collected in syringes to prevent diffusion of carbon dioxide
into and out of samples. The aluminum species in each sample are
determined by flow-injection analysis (FIA). Samples are loaded into
the FIA system directly from the syringe via a syringe pump. The sample
fills a fixed-volume (100 uL) sample loop on Channel 1, then passes
through a cation exchange column prior to filling the second sample loop
(also 100 uL) on Channel 2. The contents of each sample loop, total
reactive and nonexchangeable reactive aluminum, respectively, are
injected then by operator-prompted computer command. The sample valve
switches by computer activation, engaging the deionized water carrier
stream. The sample (bolus) is flushed by carrier into the reaction
manifold where it reacts with hydroxylamine hydrochloride/1,10-
phenanthroline, eliminating iron interference. The bolus is reacted
then with PCY. Optimum color development is achieved by adjusting the
final pH of the aluminum-PCY complex to 6.1 by additional hexamethylene
tetraamine buffer. The absorbance of the complex is subsequently deter-
mined at 580 nm. Channel 1 measures total reactive ("inorganic" plus
"organic" monomeric) aluminum; Channel 2 measures nonexchangeable reac-
tive ("organically bound" monomeric) aluminum. This method is based on
published methods (Dougan and Wilson, [1974], Rogeborg and Henriksen
[1985], and Tecator, [1984]).
2.9.3 Interferences
Holding time, storage methods, changes in temperature, dissolved carbon
dioxide concentrations, and pH may alter aluminum speciation in water
samples drastically. Samples should be analyzed as soon as possible
after collection or prior to holding time. Samples are stored at 4 °C
in the dark during transit and prior to analysis.
Iron (III) interferes with the determination of aluminum using this
method. The interference is eliminated by reducing iron (III) to iron
(II) with hydroxylamine hydrochloride and subsequent chelation with
1,10-phenanthroline.
2.9.4 Safety
The calibration standards and most chemical reagents encountered in this
method pose no serious health hazard due to external contact. Acids and
bases may cause burns and they should be handled only under a fume hood.
Protective clothing (e.g., safety glasses, gloves, lab coats) must be
worn. Hands should be washed thoroughly after handling aluminum
standards and reagents.
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2.9.5 Apparatus and Equipment
° Automated flow-injection analyze)—A computer-interfaced FIA capable
of automatic injection of samples, mixing of specified reagents for
reaction of PCV with aluminum, and detection unit (colorimeter)
capable of measuring absorbance at 580 nm.
° Cation-exchange column—A 100-mm (10-mm I.D.) teflon column with
teflon fritted inserts.
• Cation-exchange resin--An Amberlite IR 120 (14 to 50 mesh) exchange
resin is used to separate the inorganic from the organic monomeric Al
species.
° Clean-air laminar-flow hood—Used to prepare standards and reagents.
A slight negative pressure should be maintained.
2.9.6 Reagents and Consumable Materials
• Water—All water used in preparing reagents and cleaning labware must
meet the specifications for Type I reagent water as given in ASTM
publication D 1193 (ASTM, 1984).
2.9.6.1 Stock Reagents—
• Ethanol (CgHsOH)—(d = 0.785, 95%) Reagent grade.
° Hydrochloric acid—Concentrated (d = 1.19, 37%) Baker Instra-Analyzed
or equivalent grade.
° Nitric acid—Concentrated (d = 1.42, 70%) Baker Ultrex or equivalent
grade.
- 0.1 N HC1—Slowly add 8.3 mL concentrated HC1 to 500 mL water and
dilute to 1.0 L.
« Cleaning solution (0.1 N HC1 in 10% ethanol)—Slowly add 8.3 ml
concentrated HC1 to 500 mL deionized water in a 1-L graduated
cylinder. Then add 100 mL ethanol and bring to a final volume of
1.00 L with water. Prepare under fume hood.
» 10% nitric acid (1.6 N) —Slowly add 10 mL concentrated Ultrex (or
equivalent grade) nitric acid to 50 mL water. Dilute to 100 mL with
water.
° Sodium chloride solution (0.001 M NaCl)—Dissolve 0.058 g sodium
chloride (ACS reagent grade) in water and dilute to 1.00 L.
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2.9.6.2 Working Reagents—
° Reagent 1 (Iron masking solution)--Disso1 ve 7.6 g hydroxylamine
hydrochloride and 0.56 g 1,10-phenanthroline in 500 mL water and
dilute to 1.000 L. Degas by vacuum filtration through a 0.45-um
membrane filter and store in a clean polyethylene bottle.
Refrigerate until use.
• Reagent 2 (PCV solution)--Dissolve 0.375 g 3,3',4'-t 'hydroxyfuchsone-
2"-sulfonic acid (PCV) in 40 ml water. Let solution stand for
approximately 5 minutes with occasional stirring. Dilute to 1.000
L. Degas by vacuum filtration through 0.45-um membrane filter.
Store in a clean, amber-glass bottle. Smaller volumes of PCV may be
prepared if a small batch size is anticipated (<11 samples).
NOTE: Reagent 3 (PCV) MUST BE PREPARED DAILY. PCV is extremely photo-
sensitive and thermally labile. Degradation will occur after 24 hours,
notwithstanding refrigerated storage in an amber-glass bottle.
8 Reagent 3 (buffer)--Dissolve 84 g hexamethylene tetraamine in 750 mL
water. Filter the solution through a Whatman GF/C filter and
transfer the filtrate to a 1-L volumetric flask. Dilute to 1.000 L.
Transfer to a clean polyethylene bottle. Keep refrigerated until
use.
NOTE: Reagents 1 and 2 may be used until exhausted if kept refriger-
ated. However, DO NOT switch to a new batch of reagent during analysis
of a batch of samples unless a QC check is performed. If the QCCS is
not acceptable, recalibration is required. A new batch of reagents 1
and 2 may be added to a previous batch to replenish the volume prior
to calibration.
0 Ion-exchange resin--Mix the sodium form of Amberlite IR 120 (14 to 50
mesh) resin with 1 percent of the corresponding hydrogen form.
Attach a cap with a fritted end to the end of the 100-mm (10-mm
I.D.) column and fill with a slurry of Amberlite IR 120 resin beads.
Beads should fill the column; there should not be any entrapped air
or head space. Attach a cap with fritted end to the top of the
column. Pump water through the column. Collect 40-mL effluent from
the column in a beaker and measure pH. If pH does not fall between
the desired range of 4.0 and 6.0, pump through the column either
0.001 M sodium chloride to increase pH OF 0.001 M hydrochloric acid
to lower pH. Repeat until pH is between 4-6 pH units.
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2.9.6.3 Aluminum Calibration Standards--
° Stock aluminum calibration solution (1,000 mg Al /L)--Commercially
available as a certified standard for atomic absorption spectropho-
tometric analyses.
° Dilute stock aluminum calibration solution (10 mg Al/L)—Pipet
10.00 ml of 1,000 mg Al/L stock solution into a 1-L volumetric
flask containing 50 mL of water and 1.00 ml of 10% nitric acid.
Dilute to 1.000 L with water. Keep refrigerated.
° Dilute calibration standards—Daily, prepare the calibration
standards listed in the table below by diluting the appropriate
volume of 10.00 mg Al/L standard solution to 100.0 mL.
Low Calibration
High Calibration
Standard
Concen-
tration
(mg Al/L)
0.0000
0.0250
0.1000
0.2000
0.3500
mL 10.00
mg Al/L
required
0.000
0.250
1.000
2.000
3.500
Standard
Concen-
tration
(mg Al/L)
0.3500
0.5000
0.7500
1.0000
mL 10.00
mg Al/L
required
3.500
5.000
7.500
10.000
NOTE: Prepare the blank (0.000 mg Al/L) by adding 0.020 mL 10% nitric
acid to 50 mL water in a 100-mL volumetric flask. Dilute to
100 mL with water.
2.9.6.4 Aluminum Quality Control Samples--
° Stock aluminum QC solution (1,000 mg Al/L)--Commercially available
certified standard that is independent of the calibration stock
(i.e., different manufacturer).
0 Dilute stock QC solution (10.00 mg Al/L)--Pipet 10 mL of 1,000 mg
Al/L stock aluminum standard into a 1-L yolu-metric flask containing
50 mL water and 1 mL 10% nitric acid. Dilute to 1.000 L with water.
« Routine low calibration QC sample (0.075 mg Al/L)--Daily, prepare by
pipetting 7.50 mL of 10 mg Al/L QC working stock solution into a 1-L
volumetric flask containing 50 mL water. Dilute to 1.000 L with water,
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° Routine high calibration QC sample (0.600 mg Al/L)—Daily, prepare
by pipetting 6.00 ml of 10 mg Al/L working stock solution into a 100-
mL volumetric flask containing 50 ml of water. Dilute to lOO.OO ml
with water.
2.9.7 Sample Collection, Preservation, and Storage
Samples are collected in 60-cc linear polyethylene syringes with syringe
lock valves affixed to the tips. Use of this type of syringe has oeen
shown to prevent the diffusion of carbon dioxide into and out of samples
if they are kept at 4 °C. Sample preservation is therefore limited to
storage at 4 °C in the dark.
2.9.8 Calibration and Standardization
Channels 1 and 2—The dilute calibration standards (including the 0.000
mg Al/L standard) described in Section 2.9.6 are prepared prior to
analysis each day. The cation exchange column is disengaged by turning
the 6-port switching valve to the "cl/cal/QC" position, allowing the
standards to fill the sample loop on Channel 2 without passing through
the cation exchange column. A low calibration curve is generated by
injecting increasing concentrations of low calibration standards. Each
standard is injected twice during calibration. The calibration is
obtained by print-out from the computer, or manually by plotting absorb-
ance (peak area) versus concentration. The best fit line of response
versus concentration is obtained manually or by computer output. Immedi-
ately after the low calibration is performed, high calibration standards
are injected as routine samples and their respective absorbances are
recorded for future use (see Section 2.9.10.5).
2.9.9 Quality Control
2.9.9.1 Internal Quality Control--
• Detection Limit Quality Control Check Sample (QCCS)—Analyze the
detection limit QCCS (0.0200 mg Al/L) (keep the switching valve in
"cl/cal/QC" position) immediately after low calibration and high
calibration standards. The high calibration standards are not part
of the computer-generated low calibration. The measured concentra-
tion must be within 20 percent of the actual concentration or the
instrument detection limit, whichever is greater. If it is not, the
reason for the poor sensitivity and accuracy-must be isolated and
eliminated prior to sample analyses.
° Routine Quality Control Check Sample—If it is not already in
position, turn the switching valve to "cl/cal/QC" to disengage the
cation-exchange column. Analyze the routine QCCS (0.0750 mg Al/L)
after the detection limit QCCS, after every tenth sample, at the
beginning and end of each batch, and after the last sample of the
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Section
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ml/min
c
R1
R2
R3
1.8
0.8
0.8
1.0
\ RC1 RC2
\ A A, A . , A A A
V V / V V
J
Section 2.0
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Page 27 of 43
pH 6.1
(waste)
K«v:
Carrier: Oaionizad water (or 0.1 M HCt)
fll • Masking solution : Hydroxvlammonium chloride
and 1.10 Phenantfcroline cnlorida
R2 • Color reaqent: Pvrocaiacnolvioiet
R3 • Suffer solunon : Heiamernvienetetnmine and NaOH
RC1 • Reaction coil. 10 em (0.5 mm i.d.)
RC2 • Reaction coil. 30 cm (0.5 mm i.a.l
RC3 • Reaction cod. 60 cm (0.5 mm i.d.I
(a) channel l--total PCV-reactive aluminum.
Sample @ Waste
ml/min
CEC
c
R1
R2
R3
1.8
0.8
0.8
1.0
I
\ RC1 RC
\ /\ /\ A /V A
V V I V v
RC2 RC3
.pH 6.1
(waste)
Kav:
Cam«r:0*ionuM waiw (or 0.1 M HCI)
R1 • Masking solution : Hvdronvlammonium cnlond*
and 1,10 Phanantriroiin* cnlond*
R2 • Color raagant: Pyrocatacnolvioiat
R3 • 8urfar solution : Hasamatnvianxatramma and NaOH
RC1 • Raaction coil. 10cm (0.5 mm i.d.)
RC2 • Reaction coil. 30 cm lO.S mm i.d.I
RC3 • Raaction coil. 60 cm (0.5 mm i.d.)
CEC • Cation aicnanqa column
(b) channel 2—nonexchangeable PCV-reactive aluminum.
Figure 2-3. Schematic of FIA system for aluminum speciation.
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Be certain that the effluent lines from the flow cells and sample
valves are never submerged in the waste container solution. This
causes back pressure and results in poor flow cnaracteristics.
If the system appears clear of wear or clogs, begin pumping reagents
until a steady baseline is attained. Set the zero potentiometer on
each channel so that the baselines read around 1UO. ChecK the gain
on each channel to make sure it is set at 4.00. NEVER change the gain
from 4.00 unless performing the calibrations above 1.000 mg Al/L.
Also, the zero setting and baseline level should be recorded daily.
Large fluctuations in baseline level from day to day indicate a
possible change in flow rates. Consequently, lines and pump tubes
should be rechecked. Also check the flow cell for cleanliness. Use
an alcohol-soaked, lint-free tissue to wipe fingerprints and other
marks from the flow cell. The baseline will increase as analysis
proceeds during the day, however, this is corrected for, because the
baseline is subtracted from peak areas. A two-channel chart recorder
should be used to monitor the outputs of each colorimeter channel.
Such monitoring allows for detection of air bubbles, baseline shifts,
or other anomalous events occurring during sample peak reading. If
the chart recorder indicates atypical response during either sample
peak or baseline reading, the affected sample must be reanalyzed. If
a standard is affected, the instrument must be recalibrated. A pH
meter should also be employed to monitor the pH of the flow cell
effluent. The pH of the effluent should be 6.0 to 6.2. If the pH
does not fall within this range, check for (1) flow restrictions, (2)
pH meter calibration, and (3) solution preparation. Record any devi-
ations from the normal pH range for samples. There are approximately
10 seconds between the time the sample is in the flow cell and the
time it reaches the pH electrode.
2.9.10.3 Calibration Procedures--
Once the system has attained a steady baseline with reagents, place
the sample intake line into the 100-mL flask containing the lowest
concentration calibration standard (0.00 ppb Al). After two injec-
tions of standard, remove the sample line from the flask, rinse with
deionized water, and place the sample line in the next highest
standard. Inject this standard twice and continue to the next
highest standard until calibration is complete. Be certain that the
cation exchange column is disengaged during calibration ("cl/cal/QC"),
2.9.10.4 Sample Analyses--
« Detection Limit QCCS--Release the sample intake pump tube from the
peristaltic pump and connect the syringe attachment line to the
"sample in" connector on the valve. Fill a clean syringe with the
QCCS solution. Inject the detection limit QCCS immediately after
calibration.
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° Routine QCCS--Fi11 a clean syringe with the routine QCCS solution.
Inject immediately after detection limit QCCS ana following the
column breakthrough sample thereafter.
° Blank—Fill a clean syringe with deionized water. Inject the blank
following routine QCCS.
° Column Breakthrough Sample—Use the routine QCCS syringe. Turn the
switching valve to the "sample" position, thus engaging the CEC
column in-line. Inject the column breakthrough sample (routine
QCCS). Channel 2 should measure no detectable Al (i.e., result
should be within 20 percent of the blank value).
o Routine Sample Analyses—Place an acid-washed/deionized water-
rinsed 0.45-um polycarbonate filter on the end of the sample
syringe. Inject 5 ml of sample through the syringe filter into a
waste container. Place the syringe in the syringe pump unit. Be
absolutely certain that the sample intake pump tube nas oeen
released from the peristaltic pump and that the syringe pump is set
on setting "7." Make sure the syringe valve is open and turn the
syringe pump to the "mL/min" setting. The switching valve should
be in the "sample" position. Make sure no air is in the "sample
in" line while the switching valve is in the "sample" position;
this will lead to air being introduced into the cation exchange
column. An air bubble in the line prior to valve i may be removed
from the system by taking the switching valve out of the "sample"
position. After the air bubble is removed to waste, return the
valve to the "sample" position and reanalyze the sample. If an air
bubble is introduced to the column, repack the column and perform
the routine QC checks.
Analyze the column breakthrough sample and routine QCCS after every
tenth sample, at the beginning and end of each batch, and after the
last sample of the day. Results must be within specified QC windows.
2.9.10.5 High Calibration--
The high calibration standards (350, 500, 750, 1,000 ppb Al) and high
QCCS (600 ppb Al) are analyzed daily prior to sample analysis. If a
sample exhibits a measured concentration greater than 350 ppb Al but
less than 600 ppb Al, examine the high QCCS for linearity. If the
observed concentration of the 600 ppb QCCS is within 10 percent of
its nominal concentration (540 to 660 ppb Al), the measured concentra-
tion of the high sample may be accepted. If a measured concentration
of greater than 600 but less than 1,000 ppb is observed for a routine
sample, or if the high QC check criterion is not met, a new calibra-
tion line must be calculated from the high standard raw data. Also,
if more than 20 percent of the samples in a batch contain more than
350 ppb Al, a high calibration must be determined regardless of the
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acceptable high QCCS. ihe high calibration is determined from a
linear regression of peak area versus concentration of tne 350, SOU,
750, and 1,000 ppb Al standards. Check the linearity of the hign
calibration by determining the concentration of tne nigh QCCS (oOO
ppb Al) by inserting the peak area into the linear regression equa-
tion. The measured concentration must be within 10 percent of the
nominal value, or the high standards must be reanalyzed and a new
high calibration determined.
If a sample concentration of greater than 1 mg Al/L is observed, an
expanded calibration may be performed following completion of tne
remainder of the batch. Standard concentrations of 1.000, ^.000, and
3.500 mg Al/L and a QCCS of 2.500 mg Al/L are used to caliorate in
the expanded range. These standards are prepared by aading the
specified volumes of 10.0 mg Al/L standard stock solution to a clean
100-mL volumetric flask and bringing to a final volume of 10U mL.
The 2.500 mg Al/L QCCS must be prepared from the 1U.O ppb QC stock
solution.
mL 10.00
Standard Concentration mg Al/L
(mg Al/L) required
1.000 10.00
2.000 *0.00
2.500 (QCCS) 25.00
3.500 35.00
Calibration is done by reducing the gain to 1.00 (from 4.00) and
analyzing the 1.000, 2.000, and 3.500 mg Al/L standards twice each.
This is performed as a separate calibration from the normal calibra-
tion. Analyze the QCCS to ensure linearity (witnin 10*). It must be
noted that the normal limits of linearity have been reported at l.OOo
mg Al/L. Also, it is important to change the gain rather than sample
size in order to retain comparable flow characteristics. Any samples
with aluminum concentrations greater than 3.500 mg Al/L must be
diluted with deionized water adjusted to the pH of the sample with
dilute sulfuric acid. This can be done by titrating deionized water
with 0.001 N Ultrex sulfuric acid to the pH of the sample and diluting
the sample until its PCV absoroance is on-scale at a gain of 1.00.
Return the gain to 4.00 following completion of the high sample
analyses. It is very important that samples analyzed by high
calibrations be noted as such, along with their corresponding gain
and QC values to the QA group.
After completion of all sample analyses for a given day, flush the
system with water for 5 minutes. Mext, place the switching valve in
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the "cl/cal/QC" position to disengage the cation-exchange column,
increase the pump speed by 20 percent, and flush with cleaning solu-
tion for 5 minutes. Follow with another water rinse. Return the
pump to normal operating speed. Shut off instrument and computer.
If the system is not to be used for more than 2 days, pump air
through the lines. Release all pump tubes from the peristaltic pump.
2.9.11 Maintenance
Weekly and daily maintenance is critical in keeping an FIA system in
proper operation; Deviations in flow rate due to worn or constricted
lines alter the flow and mixing characteristics of the system, there-
fore, will affect the chemistry of the method. Monitor the system
constantly for any changes in flow, replace pump tubes on a regular
basis (determined by extent of use), and release tubes from the pump at
the completion of analysis. Spray silicone over the pump rollers
weekly to prolong pump tube life. The 0.5-mm 1.0. teflon tubing is
also subject to aging. Crimps in the lines can occur due to twisting
or pinching and are most often observed at the end of mixing coils.
Also, a black precipitate can develop in the lines after buffer addi-
tion, tainting the lines over time, despite the cleaning procedure
described above. Often, disconnecting the coil and-injecting cleaning
solution from a syringe will augment the cleaning process. It is also
helpful to pass air through the coil with the syringe. PCV also
gradually stains the lines. When a line appears fouled, or damaged,
replace it with a line of equal I.D. and length. If a coiled line is to
be replaced, wrap a new coil in a similar fashion. After completing a
coil-wrap, reposition the ends to release any pressure or bends that
may lead to coil-kinking.
Inspect the flow cell regularly for fingerprints, dirt, or scratches.
A dirty flow cell may be cleaned with alcohol, but a scratched or
cracked flow cell must be replaced. Therefore, exercise due caution
when handling flow cells. Maintain the colorimeter according to manu-
facturers' instructions. A poorly functioning colorimeter negates an
otherwise properly functioning system; therefore, the colorimeter
should be checked regularly. Turn off the light source for the color-
imeter prior to activating other system components and turn it on after
system components to prevent blown fuses.
The rotary valves also require regular maintenance. Weekly (or more
frequently if necessary), disassemble the valve by unscrewing the three
screws that hold the valve together, and clean all the parts with a
soft brush. Check the flanged line ends to make sure a good seal is
being made and that no constrictions exist. Check the valve housing
for wear and replace any worn components. Put the valve back together
by screwing the three screws back together as you would when changing a
tire. Do not tighten the screws too tight as the teflon may become
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warped. If the valve leaks upon reinstallation, tighten each of the
screws a little more. If tne valve still leaks, tne flangeu enas are
probably not making a good seal. Reinspect the flanges and reassemble
the valve.
2.9.12 Calculation
Results are reported in mg Al/L for both total reactive and nonexchange-
able reactive Al.
2.9.13 Precision and Accuracy
A single operator in a single laboratory analyzed various concentrations
of inorganic monomeric aluminum prepared in distilled/deionized water.
Precision and accuracy estimates are shown in Table 2-4.
Similarly, precision and accuracy were determined for the high cali-
bration range from 350 to 1,000 ug Al/L. These values are shown in
Table 2-5.
Percent recovery was determined for two natural surface water samples,
Big Moose Lake (Adirondack Mountains, New York) and Bagley Lake (Cascade
Mountains, Washington), spiked with 300 and 100 ug Al/L, respectively.
These percent recoveries are shown in Table 2-6.
2.10 DETERMINATION OF TOTAL NITROGEN
Determination of total nitrogen is a new procedure that was not used
during ELS-I. The procedure is applied to surface water samples.
2.10.1 Scope and Application
This method is applicable to the determination of total nitrogen in
natural surface waters. Total nitrogen includes inorganic nitrogen
compounds (nitrate, nitrite, and ammonia) as well as organically fixed
nitrogen (proteins, etc.).
This method is applicable to the determination of total nitrogen in the
range of 0.01 to 20 mg/L N. The minimum detection limit is approxi-
mately 0.007 mg/L (three times the standard deviation of replicate
blank analyses).
This method may give poor recoveries for organic compounds which contain
nitrogen-to-nitrogen double bonds as well as terminal nitrogen groups
(e.g., HN = C).
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TABLE 2-4. PRECISION AND ACCURACY FOR SINGLE OPERATOR/SINGLE LABORATORY
ANALYSIS OF INORGANIC MONOMERIC AT BY FIA/PCV METHOD
Nominal Al
Concentration
(M9/U
0.0
10.0
15.0
20.0
25.0
35.0
50.0
75.0
100.0
150.0
350.0
N
12
13
9
10
10
10
10
10
10
2
5
Avg. Observed
Concentration
(M9/D
4.9
9.2
15.0
20.5
24.0
34.2
49.4
70.0
99.1
150.5
350.8
Precision
(Std. Dev.)
(M9/D
3.3
2.5
2.8
2.5
3.4
2.5
2.8
3.1
2.7
4.8
3.8
Bias
lug/U
4.9
-0.8
0.0
0.5
-1.0
-0.8
-0.6
-5.U
-o.y
0.5
u.a
TABLE 2-5. PRECISION AND ACCURACY FOR SINGLE OPERATOR/SINGLE LABORATORY
ANALYSIS OF HIGH LEVELS OF INORGANIC MONOMERIC Al BY FIA/PCV METHOO
Nominal Al
Concentration
(M9/L)
350.0
500.0
750.0
1000.0
N
5
5
5
5
Avg. Observed
Concentration
(ng/L)
356.9
494.4
743.9
1004.8
Precision
(Std. Dev.)
(M9/U
9.2
11.3
13.3
-16.2
Bias
(M9/U
6.9
-5.6
-6.1
4.8
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TABLE 2-6. PERCENT RECOVERY OF MONOMERIC Al FROM TWO SPIKED UATURAL SURFACE
WATER SAMPLES ANALYZED BY THE FIA/PCV METHOD
Pre-Spike Spike Sample + Spike
Concentration Concentration Concentration Recovery
Sample N (ug/L) (ug/L) (ng/D *
Big Moose
Bagley
6
10
278.2 ± 5.6
3.3 ± 1.5
300.0
100.0
575.8 ± 7.7
105. 7 ± 2.2
99.6
102.3
2.10.2 Summary of Method
Samples are oxidized in an autoclave at 120 °C with an alkaline persul-
fate mixture. The oxidation process converts all nitrogen-containing
compounds to nitrate. The nitrate is subsequently determined colori-
metrically by FIA. During FIA, nitrate is reduced to nitrite by cadmium
reduction; the nitrite is determined by diazotizing with sulfanil amide
and coupling with N-(l-napthyl)ethylenediamine dihydrochloride to form
a highly colored azo dye, which is measured colorimetrically at 540 nm.
The procedure is based on published methods (Ebina et al. [1983J, Smart
et al. [1981], D'Elia et al. [1977], Nydahl L1978], and Tecator L1983J).
2.10.3 Definitions
° Total Persulfate Nitrogen—In a water sample, this is the total
nitrogen present that is digested by the persulfate method, including
organic N, NH4"N, N03'N, and N02~N.
2.10.4 Interferences
Turbidity may interfere with this method. If the digestate is turbid,
it can be filtered through a 0.45-um membrane prior to analysis. EuTA
is used to reduce interference from Fe, Cu, and other metals.
2.10.5 Safety
The calibration standards, sample types, and most reagents used in this
method do not pose a hazard to the analyst. Wear protective clothing
(lab coat, gloves, and safety glasses) when .preparing reagents.
WARNING
Cadmium present in the reduction column is poisonous. Extreme caution
should be taken when handling grains and solutions.
WARNING
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2.10.6 Apparatus and Equipment
° Flow-injection analyzer—Analyzer consists of injection valve, spec-
trophotometer, printer/integrator, cadmium reduction column, ana
recorder/computer data handler.
» Autoclave.
o Teflon screw-top digestion vessels.
NOTE: Clean all labware with hot 5 percent HC1 and' rinse copiously
with nitrogen-free water. Keep labware tightly sealed from the
atmosphere to reduce contamination.
2.10.7 Reagents and Consumable Materials
Reagents must be ACS reagent grade unless otherwise stated.
2.10.7.1 Reagents--
» Ammonium chloride-EDTA solution—Dissolve 85 g reagent-grade
ammonium chloride and 0.1 g disodium ethylenediamine tetraacetate
(CASRN 60-00-4) in 900 ml water. Adjust the pH to 8.5 with concen-
trated ammonium hydroxide and dilute to 1 L.
o Copper sulfate solution (2% w/v)—Di ssol ve 20 g CuSO^SH^O in 500
ml water, then dilute to 1 L.
« Hydrochloric acid (HC1)—Concentrated (d = 1.19, 37*, Baker Ultrex
grade or equivalent).
° Dilute HC1 (1 + D—Add 50 mL concentrated HC1 (3aker Instra-
Analyzed grade or equivalent) to 50 mL water.
° NED solution—Dissolve 0.5 g N-(l-naphthyl)-ethyl enedi ami ne dihy-
drochloride (CASRN 551-09-7) in 500 ml water. Filter and degas.
Store in an amber bottle at 4 °C. Prepare fresh weekly.
° Oxidizing reagent--Dissolve 3.0 g sodium hydroxide (NaOH) and 20.0 g
potassium persulfate (K2S208, N <0.001%) in 1 L water. If the total
nitrogen in a reagent blank is too high (>0.01U ppm), then the potas-
sium persulfate may be purified by recrysta-llization. Recrystal 1 ize
potassium persulfate as follows:
Step I—Dissolve 75 g potassium persulfate (reagent grade containing
less than 0.0012 N) in 500 ml water heated to 60 °C.
Step 2—Filter rapidly through loosely stoppered Pyrex wool and
cool in ice water to about 4 °C while stirring continuously.
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Step 3--Isolate the crystals by vacuum filtration on a sintered-
glass filter. Wash with small amounts of ice water (4 °C).
Step 4--Dry in vacuo over anhydrous calcium chloride. Rapid drying
in an efficient vacuum is essential in minimizing sulfuric acid
formation on the crystals.
Step 5 — Store the crystals in a vacuum desiccator over calcium
chloride.
° Sodium hydroxide(NaOH)--Crystals (98.00%, Baker Instra-Analyzed
grade or equivalent, N <0. 00032).
° Sodium hydroxide (50% w/w)--Di ssol ve 50 g sodium hydroxide in SU ml
water. Cool to room temperature. Separate supernatant from any
precipitate by transferring supernatant to a clean plastic bottle.
Store bottle tightly capped.
«• Sodium hydroxide (0.36 N)--Dilute 7.2 ml 50% NaOH to 250 ml. Store
in a borosilicate glass reagent bottle equipped with an Ascarite
C02 trap.
° Sulfanilamide solution—Dissol ve 5 g of sul fanilamide
CASRN 63-74-1) in a mixture of 26 ml concentrated HC1 and 300 ml
water, then dilute to 500 mL. Filter and degas. Store at 4 °C.
This solution is stable for several months.
« Watei — At the point of use, all water used in preparing reagents
and in cleaning labware must meet the specifications given in ASTM
D 1193 (ASTM, 1984) for Type I reagent water.
2.10.7.2 Reduction Column and Reagents--
---------------------- ........ WARNING -------------------------------
Cadmium is poisonous. Handle with extreme caution. Dispose of solu-
tion from the following treatments as hazardous wastes.
...... ------------------------ WARNING ------------- ..... - ...... - ......
° Granulated cadmium--40 to 60 mesh.
» Copperized cadmium — Prepare copperized cadmium as described below:
Step l--Wash the cadmium with dilute HC1 and rinse with water. The
color of the cadmium so treated should be silver.
Step 2--Swirl 10 g cadmium in 100 ml copper sulfate solution for 5
minutes, or until blue color partially fades. Decant and repeat
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with fresh copper sulfate solution. Continue wasnings until a
brown colloidal precipitate forms.
Step 3—Wash the cadmium-copper with water (at least 10 times) to
remove all the precipitated copper. The color of the cadmium so
treated should be black.
o Preparation of reduction column—The reduction column is an 8-mm by
50-mm low-pressure, glass chromatography column. Pack the reduction
column with copperized cadmium as follows:
Step 1 — Insert a fritted Teflon bed support into one end of the
column. Place a column plug in the same end. Fill the column with
water.
Step 2—Add copperized cadmium granules to the column while gently
vibrating the column with an electric engraving pencil. This
procedure will ensure even column packing. When the column is
packed completely, insert another fritted Teflon bea support on the
top of the column.
Step 3--Insert the packed column into the flow system using standard
1/4-28 chromatography fittings. The column is now ready for use.
Keep the column filled with water at all times. If air buboles
become trapped in the column, they can be dislodged oy vibrating tne
column while pumping carrier through the system. Repack the column
if void volumes are apparent.
2.10.7.3 Standard Solutions--
» Concentrated stock standard solution (1,000 mg/L HQ^-M total
nitrogen)--Dissolve 0.60681 g sodium nitrate (NaN03, ultrapure grade,
dried at 110 °C for 2 hours and stored in a desiccator) in water
and dilute to 100.00 ml with water. Store at 4 °C. Prepare weekly.
° Dilute stock standard solution (10.00 mg/L N03-N total nitrogen) —
Dilute 1.000 ml of the 1,000-mg/L total-nitrogen solution to 100.00
ml with water. Store at 4 °C.
° Daily calibration standards—Daily, prepare the calibration
standards listed in the table below by adding the appropriate
volume of 10.00-mg/L total-nitrogen standard and diluting to lUO ml.
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2.10.7.4
Total-nitrogen
standard
(mg/L
ml of 10.00-mg/L
total-nitrogen
standard required
0.000
0.010
0.030
0.050
0.000
0.100
0.300
0.500
Total-nitrogen
standard
(mg/L)
0.100
0.500
1.000
ml of lO.Ou-mg/L
total-nitrogen
standard required
1.000
5.000
10.000
° Concentrated column efficiency (CE) stock standard solution
(100 mg/L iM02-TN)--Di ssol ve 0.4502 g sodium nitrite (NaN02, ACS
reagent grade, dried at 100 °C for 2 hours and stored in a desic-
cator) in water and dilute to 100.00 mL. Prepare daily.
• CE standard (5.000 mg/L N02-TN)— Daily, dilute 0.500 mL of tne
1,000-mg/L NO£-TN solution to 100. uO mL with water.
Quality Control Check Samples (QCCS) —
' QC Stock Solution (1,000 mg/L total nitrogen)--0issol ve 0.606di g
NaN03 (ultrapure grade, dried at 110 "C for 2 hours and stored in a
desiccator) in water and dilute to 100.00 mL. Store at 4 °C. NaNOa
must be from a source independent of that used to prepare the
concentrated stock standard solution.
• Detection limit QC sample (0.030 mg/L total nitrogen)--0aily, dilute
0.0300 mL QC stock solution to 1,000.00 mL with water.
• Routine QCCS (0.500 mg/L total nitrogen)--Daily, dilute 0.0500 mL
QC stock solution to 100.00 mL with water.
• CE QC Stock Solution (100 mg/L NOg-TN)— Dissolve 0.4502 g
(ACS reagent grade, dried at 110 °C for 2 hours and stored in
desiccator; must be from a source independent of that used to
prepare the concentrated CE stock standard solution) in water and
dilute to 100.00 mL. Store at 4 °C.
• CE QCCS (0.500 mg/L N02-TN)— Daily, dilute 0.0500 mL CE QC stock
solution to 100.00 mL with water.
2.10.8 Sample Collection. Preservation, and Storage
An unfiltered 100-mL sample contained in an acid-washeo. bottle is
preserved with 0.05 mL Ultrex grade concentrated ri^S04 (pH<2). Store
sample at 4 "C in the dark when not in use.
2.10.9 Calibration and Standardization
° Colorimeter cal ibration--The colorimeter is calibrated before each
batch of samples is analyzed. The seven daily total-nitrogen
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calibration standards (including 0.000 mg/L) are analyzed, and a
calibration curve is generated from their responses.
2.10.10 Quality Control
2.10.10.1 Routine Quality Control —
" Laboratory dupl icates--Analyze one sample per batch in duplicate
(including digestion). Duplicate precision (expressed by relative
standard deviation) must not exceed 10 percent.
° Reagent blank—Prepare and analyze one reagent blank per batch. A
reagent blank contains only the reagents used in processing. It
must contain less than 0.010 mg/L total nitrogen.
° Detection limit QCCS--Analyze the detection limit QCCS once per
batch prior to sample analysis. The measured result must be with-
in 20 percent of the actual concentration.
• ° Routine QCCS--Analyze the routine QCCS prior to sample analysis,
after every 10 samples are analyzed, and after the final sample is
analyzed. The measured concentration must be within 10 percent of
the actual concentration.
2.10.10.2 Reduction Column Quality Control--
To ensure that the reduction column completely reduces nitrate to
nitrite, nitrite samples (CE standards and CE QCCS) must be analyzed.
• CE standard—Analyze a 5.000-mg/L N02~N standard after the caliora-
tion standards have been run. Determine the efficiency of the
column using the equation below:
N03 peak height
Column Efficiency (Z) = - x 100
peak height
If the column is less than 95 percent efficient, reactivate or
replace the column so that 95 percent or greater efficiency is
achieved.
CE QCCS— Analyze the CE QCCS after every routine CE standard
analysis. The measured concentration must be within iO percent
of the actual concentration. If it is not, checx the instrument
operation and sample preparation.
2.10.11 Procedure
Step I—Set up the FIA system as indicated in Figure 2-y.
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Cd - red
Kay: S • Sample)
B • Neutralizing Straam (0.36N NaOH)
C • Carrier (ammonium chlorida • EOTA solution
R1 • Diazotizing Raagant (Sulfanilamida solution)
R2 • Color Raagant (NED solution)
Cd-red - Cadium Reduction Column
RC1 • Reaction Coil. 12 cm (0.5 mm i.d.)
RC2 - Reaction Coil. 30 cm (0.5 mm i.d.)
RC3 • Reaction Coil. 60 cm (0.5 mm i.d.)
Waste
Detector
Figure 2-9. Schematic of FIA system for determination of total nitrogen.
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Step 2--Allow all reagents to run through the system for 10 minutes.
Step 3--Analyze a 0.500-mg/L N02~N standard on an ion chromatograph
to determine if any nitrate is present.
Step 4--Add 5.00 ml oxidizing reagent to 5.00 ml sample (routine
samples, calibration standards, reagent blank, and QCCS samples
included) in a Teflon digestion vessel and cap the vessel.
Step 5--Autoclave sample at 120 "C for 30 minutes, then cool to room
temperature.
Step 6— Analyze a 0.500-mg/L NO£-N sample and a 0.500-mg/L
sample. Calculate the column efficiency using the equation given
above. If the column is less than 95 percent efficient, reactivate or
replace the column until 95 percent or greater efficiency is achieved.
Step 7--Load the autosampler of the FIA system, and start the analysis,
Analyze the samples in the following order:
a. Calibration Standards f. CE QCCS
b. CE QCCS and 0.500-mg/L g. Ten Samples
N03-TN Standard
c. Reagent Blank h. Routine QCCS
d. Detection Limit QCCS i. Q.500-mg/L Calibration
Standard
e. Routine QCCS j. Calibration Blank
Step 8--Repeat steps 7e through 7i until all samples are analyzed.
Step 9--Dilute and reanalyze all samples that exceed the calibrated
range.
2.10.12 Calculations
Construct a calibration curve for total nitrogen by plotting the
measured response for the calibration standards versus concentration.
From the calibration curve and response for the samples, calculate the
sample concentration. Report results as mg/L total nitrogen.
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2.10.13 Precision and Accuracy
In previous studies (Ebina et al., 1983; Tecator, 1983), for total
nitrogen concentrations within the range 0.14 to 2.0 mg/L, the rela-
tive precision of the method ranged from 0.4 to 2.5 percent. In a
single laboratory (Ebina et al., 1983), using river water spiked with
total nitrogen in the range 2.5 to 10.0 M9. the recovery (accuracy)
varied from 99 to 103 percent.
2.11 COLLECTION, PRESERVATION, AND STORAGE OF CHLORPHYLL a SAMPLES
Surface water samples are filtered in the field, and the filter pad
with plankton is shipped to the processing facility. There the sample
is logged in and is shipped to the analytical laboratory. Chlorophyll
is extremely light-sensitive, and samples must be protected from expo-
sure to light. All sample-handling operations should be carried out
under subdued lighting. In addition, samples should never be exposed
to acid vapors.
2.12 REFERENCES
American Public Health Association, 1980. Standard Methods for the
Examination of Water and Wastewater, 15th Ed. APHA, Washington,
D.C.
American Society for Testing and Materials, 1984. Annual Book of ASTM
Standards, Vol. 11. 01, Standard Specification for Reagent Water,
01193-77 (reapproved 1983). ASTM, Philadelphia, Pennsylvania.
D'Elia, C. F., P. A. Stendler, and N. Corwin, 1977. Determination of
Total Nitrogen in Aqueous Samples Using Persulfate Digestion.
Limnol. Oceanogr., v. 22, pp. 760-764.
Dougan, W. K. and A. L. Wilson. 1974. The Absorptiometric Determina-
tion of Aluminum in Water: A Comparison of Some Cromogenic
Reagents and the Development of an Improved Method. Analyst
v. 99, pp. 413-430.
Ebina, J., T. Tsutsui, and T. Shirai, 1983. Simultaneous Determina-
tion of Total Nitrogen and Total Phosphorus in Water Using
Peroxodisulfate Oxidation. Water Res., y. 17, pp. 1721-1726.
Hillman, D. C., J. F. Potter, and S. 0. Simon, 1986. National Surface
Water Survey, Eastern Lake Survey (Phase I -- Synoptic Chemistry)
Analytical Methods Manual. EPA 600/4-86-009. U.S. Environmental
Protection Agency, Las Vegas, Nevada.
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Nydahl, F. 1978. On the Peroxodisulfate Oxidation of Total Nitrogen
in Waters to Nitrate. Water Res., v. 12, pp. 1123-1130.
Rogeborg, E.J.S. and A. Henriksen. 1985. An Automated Method for
Fractionation and Determination of Aluminum Species in Freshwaters.
Vatten v. 41, pp. 48-53.
Smart, M. M., F. A. Reid, and J. R. Jones, 1981. A Comparison of
Persulfate Digestion and the Kjeldahl Procedure for Determination
of Total Nitrogen in Freshwater Samples. Water Res. v. 15, pp.
19-921.
Tecator Application Sub Note, 1983. ASN 62-01/83. Determination of
the Sum of Nitrate and Nitrite in Water by Flow Injection
Analysis. Tecator, Hdgana's, Sweden.
Tecator. 1984. Determination of Aluminum in Water and Soil Extracts
by Flow Injection Analysis. Technical Note S-263, Tecator,
Hoganas, Sweden.
U.S. EPA (Environmental Protection Agency), 1983 (revised). Methods
for Chemical Analysis of Water and Wastes. EPA-600/4-79-020.
U.S. EPA, Cincinnati, Ohio.
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3.0 ANALYTICAL LABORATORY OPERATIONS
3.1 SUMMARY OF OPERATIONS
Sample aliquots are shipped from the processing facility to the contract
analytical laboratories for analysis. For each sample, the processing
facility ships four (snowmelt) or seven (surface water) aliquots. Each
aliquot has been processed differently, depending on the analytes for
which the aliquot will be analyzed. A brief description of each aliquot
and its corresponding analytes is given in Table 3-1.
The analyses must be completed within the prescribed holding times
(Table 3-2) or a penalty is assessed. Strict QC requirements must be
followed throughout the analyses. Finally, the sample results must be
reported in the proper format, within a specified time, for entry into the
NSWS data base.
3.1.1 Sample Receipt and Handling
Ship samples to the contract analytical laboratory by overnight delivery
service. Upon receipt, measure the temperature Inside the shipping
container and record the temperature on the shipping form (Form 3). Log
in samples and ensure that the samples listed on the shipping form have
actually been received. Note anything unusual (such as leaking samples)
on the shipping form.
Store aliquots 2, 3, 4, 5, and 6 in the dark at 4 °C when not in use.
Store the samples at 4 °C for 6 months or until the laboratory is
notified by the QA manager.
Clean all labware that comes into contact with the sample (such as
autosampler vials, beakers, etc.) as described in Hillman et al. (1986).
3.1.2 Sample Analysis
The analytes to be determined in each sample and the corresponding
measurement methods are listed in Table 3-3, and the method protocols
are provided in Sections 3.2 through 3.11.
3.1.3 Internal Quality Control Requirements
QC is an integral part of sample analysis. Method QC requirements
common to all methods are described in this section. QC requirements
specific to a single method are provided in the description for that
method.
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TABLE 3-1. SURFACE WATER AND SNOUMELT ALIQUOTS, CONTAINERS, PRESERVATIVES,
AND CORRESPONDING PARAMETERS TO BE MEASURED AT THE ANALYTICAL LABORATORY
Aliquot Container3
Preservative and
Description
Parameters
1
2b
3b
4b
cD
cD
250 mL
(125 mL)
acid-washed
15 mL
acid-washed
250 mL
(125 mL)
not
acid-washed
125 mL
(125 mL)
acid-washed
500 mL
(250 mL)
not
acid-washed
125 mL
acid-washed
Filtered, acidified
with HN03 to pH <2
MIBK-hydroxyqui no! i ne
extract
Filtered
Filtered, acidified with
H2S04 to pH <2
Raw, unfiltered
Unfiltered, acidified with
HoSOd to pH <2
Ca, Mg, K, Na, Mn, Fe
Al (total extractable)
Cl", F', S042", N03~, Si02
DOC, NH4+
pH, BNC, ANC,
specific conductance, DIG
P (total)
7 125 mL Unfiltered, acidified with Al (total)
acid-washed HN03 to pH <2
aSnowmelt container volumes in parentheses.
^Aliquots 2, 3, 4, 5, and 6 must be stored at 4 °C in the dark.
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TABLE 3-2. SAMPLE HOLDING TIMES
Holding
Time Parameter
7 days A1 (total extractable), N03~a, pHb
14 days ANC, 3NC, DIG. DOC. specific conductance
23 days Cl", F", NH^, P (total), Si02, S042"
28 days0 Al (total). Ca. Fe, K. Mg. Mn. Na
aAlthough EPA (U.S. EPA. 1983) recommends that nitrate in unpreserved
samples (unacidified) be determined within 48 hours of collection, evidence
exists (Peden, 1981. and APHA et al., 1985) that nitrate is stable for 2 to 4
weeks if stored in the dark at 4 °C.
^Although EPA (U.S. EPA, 1983) recommends that pH be measured immediately
after sample collection, evidence exists (McQuaker et al., 1983) that pH is
stable for as long as 15 days if the sample is stored at 4 °C and is sealed from
the atmosphere. Seven days is specified here as an added precaution. The pH
also is measured in a sealed sample at the field station within 12 hours of
sample collection.
cAlthough EPA (U.S. EPA, 1983) recommends a 6-month holding time for these
metals, this study requires that all metals be determined within 28 days of
sample collection. The shorter holding time is required here to ensure that
significant changes do not occur and to obtain data in a timely manner.
3.1.3.1 Method Quality Control--
Each method contains specific QC steps which must be performed to
ensure data quality. Table 3-4 is a brief summary of the required QC
checks and control limits, as well as the corrective actions that are
to be taken when QC checks fall outside the control limits. QC steps
common to all (or most) of the methods are described below; QC steps
specific to a single method are detailed in the method protocol.
° Calibration Verification QC Check Sample—After performing the cali-
bration step for a method, verify the calibration (to ensure proper
standard preparation, etc.) prior to sample analysis by analyzing a
QC check sample (QCCS). The QCCS is a known sample that contains
the analyte of interest at a concentration in the low- to mid-
calibration range. Furthermore, the QCCS must be independent of the
calibration standards.
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TABLE 3-3.
PARAMETERS AND CORRESPONDING MEASUREMENT METHODS
USED 8Y THE ANALYTICAL LABORATORY
Parameter
Method
1. Acid neutralizing capacity (ANC)
2. Aluminum, total
3. Aluminum, total extractable
-------
TABLE 3-4. SUMMARY OF INTERNAL METHOD QUALIFY CONTROL CIILCKS
Parameter or Method
AtlC. BNC. pH
QC Check
Control Limits
Corrective Actio»d
1. Titrant standardization cross- 1. Relative difference <5t 1. Restandardize titrants.
check
2. Electrode calibration (Nernstian 2. Slope = 1.00 t O.Ob
response check)
3. pH QCCS (ph 4 and 10) analysis 3. pH 4 = 4.00 i 0.115
pH 10 = 10.00 t 0.05
4. Blank analysis (salt spike) 4. [Blank] £10 peq/L
5. Duplicate analysis S. RSD <10t
2. Recalibrate or replace
electrode.
3. Recalibrate electrode.
4. Prepare fresh KCI spike
solution.
5. Refine analytical
technique. Analyze
another duplicate.
6. Protolyte comparison
6. See method (section 3.2). 6. See method (section J.2
QIC. DOC, la.
Ions (Cl". F" [total
dissolved], Nh1/.
N03~, S04Z"), Metals
(AT [total], Al D.
[total extractable],
Ca, Fe, K. Mg. Mn.
Ha). 2a.
P (total), Si02,
Specific
Conductance b.
Initial QCCS analysis la.b.
(calibration and verification)
Continuing QCCS analysis
(every 10 samples)
Detection limit determination 2a.
(weekly)
The lesser of the 99i
confidence interval or
value given in Table 3-5
Detection limit
< values in Table 1-1
Detection limit QCCS analysis
(daily; metals and total P
only)
b. t Recovery = 100 * 20t
3. Blank analysis
3a.
Blank <2 times detec-
tion limit (except
specific conductance)
Blank <0.9 uS/cm
(specific conductance
only)
la. Prepare new standards
and recalibrate.
b. Recalibrate. Reanalyze
associated samples.
2a,b. Optimize instrumentation
and technique.
3a,b. Determine and eliminate
contamination source.
Prepare fresh blank
solution. Reanalyze
associated samples.
4. Duplicate analysis
Duplicate precision URSD) 4. Investigate and eliminate
< values given in Table source of imprecision.
T-l Analyze another duplicate.
S. Resolution test (1C only) 5. Resolution >60I
*To be used when QC check is outside control limits.
5. Clean or replace separator
column. Recalibrate.
TJ O XJ (/I
Qi fa tt> CO
ua <-i < r.
n> n> -•• r»-
.. vn _j.
LT) —'• O
o rj
O U3 13
-tl •"». l~>
cx> *- •
in -~j o
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For each batch or samples, analyze the calibration 'QCCS immediately
after calibration, after every 10 sample analyses, and after the
final sample analysis. Plot the measured analyte concentration in
the QCCS on a control chart and develop the 95-percent and 99-percent
confidence intervals. The 99-percent confidence interval must be
within the control limits given in Table 3-5. (The limits in Table
3-5 may be used as initial limits until enough data are obtained to
generate a control chart.) If the 99-percent confidence interval
is not within the required limits, a problem exists with the experi-
mental technique or with the QCCS itself. For a given analysis,
there must be at least seven successive points more on one side of
the theoretical mean than on the other to indicate a bias. If
bias is indicated, analyses must be stopped and an explanation
sought.
The measured analyte concentration in the QCCS must be within the 99-
percent confidence interval. Obtain an acceptable result before
making further sample determinations. If unacceptable results are
obtained, repeat the calibration step and reanalyze all samples
analyzed since the last acceptably analyzed QCCS.
° Detection Limit Determination and Verification—Determine the
detection limit weekly for all parameters (except pH and specific
conductance, for which the term "detection limit" does not apply).
For NSWS, the detection limit is defined as three times the standard
deviation of 10 nonconsecutive reagent or calibration blank analyses.
In the case where a signal is not obtained for a blank analysis
(such as in ion chromatographic analyses or autoanalyzer analyses),
analyze a low-concentration standard (concentration about three to
four times the detection limit) rather than a blank. Detection
limits must not exceed the values listed in Table 1-1. If a detec-
tion limit is not met, refine the analytical technique and optimize
any instrumentation variables until the detection limit is achieved.
To verify the detection limit daily for the determination of metals
and total P, analyze a detection limit QCCS after calibration and
prior to sample analysis. The detection limit QCCS must contain the
analyte of interest at two to three times the detection limit. The
measured concentration must be within 20 percent of the true concen-
tration. If it is not, the detection limit.is questionable.
Determine the detection limit as describe'd above.
° Blank Analysis—Once per batch, analyze a calibration blank as a
sample. The calibration blank is defined as a 0-mg/L standard (con-
tains only the matrix of the calibration standards). The measured
concentration of the calibration blank must be less than twice
the instrumental detection limit. If it is not, the blank is
contaminated or the calibration is in error at the low end. Prior
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TABLE 3-5. MAXIMUM CONTROL LIMITS FOR QUALITY CONTROL SAMPLES
USED IN THE ANALYTICAL LABORATORY
Parameter
Al , total extractable
Al , total
Ca
cr
DIC
DOC
F~, total dissolved
Fe
K
Mg
Mn
Na
NH4+
N03-
P, total
Si02
so42-
Specific conductance
Maximum Control Limit (% Difference from
Theoretical Concentration of QC Sample)
±20%
±20%
±5%
±5%
±10%
±10%
±5%
±10%
±5%
±5%
±10%
±5%
±10%
±10%
±20%
±5%
±5%
±2%
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to sample analysis, investigate and eliminate the contamination
source and repeat the calibration.
Prepare and analyze a reagent blank for the three methods that
require sample preparation (dissolved Si02, total P, and total Al).
A reagent blank contains all the reagents (in the same quantities)
used in preparing a real sample for analysis. Process the blank
using the same procedures (digestions, etc.) used to process a real
sample. The measured concentration of the reagent blank must be
less than twice the required detection limit (Table 1-1). If it is
not, the reagent blank is contaminated. Investigate and eliminate
the contamination source. Prepare and analyze a new reagent blank
and apply the same criteria. After the contamination is eliminated,
reanalyze all samples associated with the contaminated blank.
Contact the QA manager if a problem concerning a contaminated reagent
blank cannot be rectified.
Prepare one reagent blank with each set of samples processed at one
time. For example, if two sample batches are processed together,
only one reagent blank must be processed. Report the concentration
of the single reagent blank for both batches. On the other hand, if
a sample batch is split into groups that are processed at different
times, a reagent blank must be prepared for each group. In this
case, report all reagent blank values for the batch. Identify in a
cover letter which reagent blank values are associated with which
samples.
Duplicate Sample Analysis—For each parameter, prepare and analyze
one sample per batch in duplicate. If possible, choose a sample that
contains analyte at a concentration greater than five times the
detection limit. Using the equation below, calculate the percent
relative standard deviation (2RSD) between duplicates:
S
2RSD = -3- x 100
x
where
n-1
The duplicate precision URSD) must not exceed the value given in
Table 1-1. If duplicate SRSD values fall outside the values given in
Table 1-1, a problem exists (such as instrument malfunction, calibra-
tion drift, etc.). After finding and resolving the problem, analyze
a second sample in duplicate. Acceptable duplicate sample results
must be obtained before additional samples are analyzed.
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3.1.3.2 Overall Internal Quality Control--
After each parameter in a sample has been determined, two procedures
exist for checking the correctness of analyses. These procedures are
outlined below.
Anion-Cation Balance—Theoretically, the (ANC) of a sample equals
the difference between the concentrations of cations and anions in
a sample (Kramer, 1982). In practice, this is rarely true due to
analytical variability and to ions that are present but are not
measured. For each sample, calculate the percent ion difference
(210) as follows:
[ANC] + Z anions - z cations
SID " - x 100
TI
where
[ANC] = Measured ANC
2~
E anions = [Cl~] + [F~] + [N03~] + [S04~]
Z cations = [Ca2+] + [K+] + [Mg2+] + [Na+] + [NH4+]
TI (Total ion strength) = [ANC] + Z anions + Z cations + 2 [H+]
[H+] = (lO'PH) x 106 ueq/L
NOTE: All concentrations are expressed as microequivalents/1 iter
(ueq/L). Table 3-6 lists factors for converting mg/L to
ueq/L for each parameter.
The SID must not exceed the limits given in Table 3-7. An unaccept-
able value for %ID indicates the presence of unmeasured ions or an
analytical error in the sample analysis. For the samples in this
study, the ions included in the SID calculation are expected to
account for 90 to 100 percent of the ions in a sample. Note that
the ANC term in the calculation accounts for protolyte ions that are
not specifically determined (such as organic acids and bases).
For samples that do not meet the SID criteria, examine the data for
possible causes of unacceptable SID. Often, the cause is improper
data reporting (misplaced decimal point, incorrect data reduction,
switched sample IDs, etc.). After examining the data, redetermine
each parameter that is suspect. If an explanation for the poor SID
cannot be found and the problem cannot be corrected, contact the QA
manager at EMSL-LV for further guidance.
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TABLE 3-6. FACTORS FOR CONVERTING mg/L TO
Factor Factor
Ion (ueq/L per mg/L) Ion (ueq/L per mg/L)
Ca2+ 49.9
CT 28.2
F~ 52.6
K+ 25.6
Mg2+ 82.3
Na+
NH4+
NO-,'
j
so,?-
43.5
55.4
16.1
20.8
TABLE 3-7. CHEMICAL REANALYSIS CRITERIA
A. Anion-Cation Balance
Maximum
Total Ion Strength (ueq/L) % Ion Difference3
<50 60
>50<100 30
>_100 15
B. Specific Conductance
Maximum
Measured Conductance (uS/cm) % Conductance Difference3
<5 50
>_5<30 30
>30 20
alf the absolute value of the percent difference exceeds this value, the
sample is reanalyzed. When reanalysis is indicated, the data for each
parameter are examined tor possible analytical error. Suspect results are
redetermined and the percent differences are recalculated (Peden, 1981). If
the differences are still unacceptable or no suspect data are identified,
contact the QA manager tor guidance.
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Conductivity Balance—Estimate the specific conductance of a sample
by summing the equivalent conductances (at infinite dilution) for
each measured ion. Calculate the equivalent conductance for each
ion by multiplying the ion concentration by the appropriate factor
given in Table 3-8. Calculate the percent conductance difference
(%CD) as follows:
calculated cond. - measured cond.
% CD = x 100
measured cond.
The %CD must not exceed the limits listed in Table 3-7. As with the
IID calculation, an unacceptable value for %CD indicates either the
presence of unmeasured ions or an analytical error in the sample
analysis. For the samples collected, the ions included in the %CD
calculation are expected to account for 90 to 100 percent of the
ions in a sample. However, in contrast to the %ID calculation,
there is no term in the %CD calculation to account for protolytes
not specifically determined.
For samples that do not meet the ZCD criteria, examine the data
for possible causes of the unacceptable 2CD, such as improper data
reporting or analysis. The presence or absence of unmeasured
protolytes can be tested by the procedures described in Section 3.2.
Note that the absence of unmeasured protolytes is positive evidence
that the %CD exceeds the maximum difference due to analytical error.
Redetermine each parameter that is identified as suspect. If an
explanation for the poor 2CD cannot be found and the problem cannot
be corrected, contact the QA manager at EMSL-LV for further guidance.
3.1.4 Data Reporting
Record the results from each method on the data form indicated in Table
3-9 (blank data forms are included in Appendix B). Report results to
the number of decimal places in the actual detection limit; however,
report no more than four significant figures. Sample results from
reanalyzed samples (occasionally samples are reanalyzed for QC reasons)
are annotated by the letter R. Results obtained, by standard additions
are annotated by the letter G. These and other data qualifiers are
listed in Table 3-10. After the forms are completed, the laboratory
manager must sign them, indicating that he or she has reviewed the data
and that the samples were analyzed exactly as described in this manual.
All deviations from the procedures in this manual require the authoriza-
tion of the QA manager; authorization must be obtained before samples
are analyzed.
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TABLE 3-8. CONDUCTANCE FACTORS OF IONS3
Specific Specific
Conductance Conductance
(uS/cm at 25 °C) (uS/cm at 25 °C)
Ion per mg/L Ion per mg/L
Ca2+
cr
co32-
H+
HC03"
Mg2t
2.60
2.14
2.82-
3.5 x 105
(per mole/L)
0.715
3.82
Na+
NH4+
so42'
NOf
K+
OH-
2.13
4.13
1.54
1.15
1.84
1.92
(per
x 105
mole/L)
[H+] moles/L = 10~P
pH = pH determined at V=0 of the BNC titration.
Kw
[OH'] =
[H+]
5.080 [DIC(mg/D] [H+] K,
HC03" = -
[H+]2 + [H+] K1 + Kx K2
2_ 4.996 [DIC(mg/D] KI K2
ru"*"i2 j. ru"'"i v 4. v v
Ln J T Ln J INI T l\i I\o
K! = 4.4463 x 10'7 '
K2 = 4.6881 x 10"11
3APHA et al., 1985, and Weast, 1972.
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TABLE 3-9. DATA FORMS USED BY THE ANALYTICAL LABORATORY
Data Form Description
11 Summary of sample results
13 ANC and BNC results
14a QC data for ANC and BNC analyses
15a Specific conductance (measured and
calculated)
16a Anion-cation balance calculations
17 Ion chromatography resolution test
18 Detection limits
19 Sample holding time summary
20 Blank and QCCS results
22 Duplicate results
23 Standard addition results
aForm is not required in data package but is recommended for internal
QC use.
Copies of raw data must be submitted as requested by the program manager.
All original raw data must be retained by the lab until notified other-
wise. Raw data include data system printouts, chromatograms, notebooks,
QC charts, standard preparation data, and all information pertinent to
sample analysis.
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TABLE 3-10. NATIONAL SURFACE WATER SURVEY DATA QUALIFIERS
Qualifier Indicates
F Result outside QA criteria (with consent of QA manager)
G Atypical result; has already been reanalyzed and confirmed by
the lab manager
H Holding time exceeded criteria, consent of QA manager required
J Result not available; insufficient sample volume shipped
;< Result not available; entire aliquot not shipped
L Result not available; analytical interference
M Result not available; sample lost or destroyed by lab
N Not required
P Result outside QA criteria, but insufficient volume for
reanalysis
Q Result outside QA criteria
R Result from reanalysis
S Contamination suspected
T Leaking container
U Result not required by procedure
V Anion-cation balance outside criteria due to DOC
W ^Difference (ZD) calculation (Form 14) outside criteria
due to high DOC
Y Available for miscellaneous comments
Z Available for miscellaneous comments
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3.2 DETERMINATION OF ANC, BNC, AND pH
Tnis procedure is a slight modification of the one used during ELS-I.
For ELS-II, pH is determined prior to sample titration rather than during
sample titration.
3.2.1 Scope and Application
This procedure is applicable to the determination of pH, ANC, and BNC in
weakly buffered natural waters of low ionic strength. For calculation
purposes, it is assumed that the lakes in the survey are represented by
a carbonate ion system; hence, the ANC and BNC definitions are made in
relation to the carbonate ion species (Kramer, 1982; Sutler, 1982). The
soluble reacting species are ^03, HC03, and C03 .
3.2.2 Summary of Method
The pH is determined prior to the start of sample titration. The same
electrode used during titration is used to measure initial pH (U.S. EPA,
1983; McQuaker et al., 1983; NBS, 1982). While pH is monitored and
recorded, samples are titrated with standardized acid (base).
The ANC and BNC are determined by analyzing the titration data using a
modified Gran analysis technique (Kramer, 1982; Butler, 1982; Kramer,
1984; Gran, 1952). The Gran analysis technique linearizes the titration
curve. For titration data on both sides of the equivalence point, a
corresponding Gran function data point is calculated. When the Gran
function is plotted versus volume of titrant added, a linear curve is
obtained. The equivalent point is interpolated from where the line
crosses the volume axis.
The air-equilibrated pH is determined after equilibrating the sample
with 300 ppm C02 in air. Air equilibration is expected to normalize pH
values by factoring out the day-to-day and seasonal fluctuations in
dissolved C02 concentrations.
3.2.3 Interferences
Electrodes must be cleaned and maintained to prevent fouling by organic
substance in samples. Calculations are performed assuming that the samples
are represented by a carbonate system. This "is generally true in natural
surface waters. Organic protolytes may cause the Gran function plots to
exhibit some nonlinearity.
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3.2.4 Safety
The standards, sample types, and most reagents pose no hazard to the
analyst. Protective clothing (lab coat, gloves, and safety glasses)
must be used when handling concentrated acids and bases.
Gas cylinders must be secured in an upright position.
3.2.5 Apparatus and Equipment
° pH/mV Meter--A digital pH/mV meter capable of measuring pH to ±0.01 pH
unit, potential to ±1 mV, and temperature to ±0.5 "C must be used. The
meter also must have automatic temperature compensation capability.
° pH Electrodes — High-quality, low-sodium glass pH and reference elec-
trodes must be used. (Gel-type reference electrodes must not be used.)
A combination electrode is recommended (such as the Orion Ross
combination pH electrode or equivalent), and the procedure is written
assuming a combination electrode is used.
« Buret--A microburet capable of precisely and accurately delivering 10
to 50 uL must be used (relative error and standard deviation less than
0.5 percent).
° Teflon Stir Bars.
° Variable-Speed Magnetic Stirrer.
° Plastic Gas Dispersion Tube.
NOTE: A glass dispersion tube must not be used because it can add
ANC to a sample. Plastic dispersion tubes are available in
most aquarium supply stores.
° Titration System — A commercial titration instrument may be used in
place of the pH/mV meter, pH electrode, and buret if the instrument
meets all required specifications.
3.2.6 Reagents and Consumable Materials
° Carbon Dioxide Gas (300 ppm C0£ in air)--Certified standard grade.
Hydrochloric Acid Titrant (0.01N HCD— Add 0.8 ml concentrated hydro-
chloric acid (HC1, 12N, ACS reagent grade or equivalent) to 500 ml
water, then dilute to 1.00 L with water. Standardize as described in
Section 3.2.8.1.
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Nitrogen Gas (N£)—C02~free.
° Potassium Chloride Solution (0.10 M KC1 I—Dissolve 75 g KC1 (Alfa
Ultrapure or equivalent) in water, then dilute to 1.00 L with water.
0 Potassium Hydrogen Phthalate (KHP)— Dry 5 to 10 g KHP (ACS-certified
primary standard grade or equivalent) at 110 °C for 2 hours, then store
in a desiccator.
° pH Calibration Buffers (pH 4, 7, and 10)— NBS-traceable pH buffers at
pH values of 4, 7, and 10.
• pH QC Samples (pH 4 and 10)— pH 4 QC sample: Dilute 1.00 mL standard-
ized 0.01N HC1 titrant to 100.00 mL with water. The theoretical pH is
calculated by
pH = -log
— pH 10 QC sample: Dilute 1.00 ml standardized 0.01N NaOH titrant to
100.00 ml with water. The theoretical pH is calculated by
pH = -log
100
» Sodium Carbonate (Na2C03)— Dry 5 to 10 g NagCOs (ACS-certified primary
standard grade or equivalent) at 110 °C for 2 hours, then store in a
desiccator.
° Sodium Hydroxide Stock Solution (50 percent w/v NaOHJ—Dissolve 100 g
NaOH (ACS reagent grade or equivalent) in 100 mL water. After cooling
solution and allowing precipitate to settle (may be hastened by centri-
fugation), transfer the supernatant to a polyethylene bottle. Store
bottle tightly capped and avoid exposing solution to atmosphere.
• Sodium Hydroxide Titrant (0.01 N NaOH)— Dilute 0.6 to 0.7 mL 50 per-
cent NaOH to 1.0 L with water. Standardize as described in Section
3.2.8.2.
o Water — At the point of use, water used to prepare reagents and standards
must conform to ASTM specifications for Type I reagent water (ASTM, 1984)
3.2.7 Sample Collection, Preservation, and Storage
The sample for which ANC, BNC, and pH are to be determined is delivered
to the lab in a 500-mL amber polyethylene bottle (aliquot 5). Store at
4 °C and minimize atmospheric exposure.
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3.2.8 Calibration and Standardization
3.2.8.1 Standardization of HC1 Titrant--
Step 1—Weign about 1 g anhydrous Na2C03 to the nearest 0.1 mg, dissolve
in water, then dilute to 1.000 L. Calculate the concentration by
wt.
23
106.00 g 1 mole
x -
1L
mole
2 ueq
NOTE: Fresh
solution is to be prepared just before use.
Step 2 — Calibrate the pH meter and electrode as recommended by the
manufacturer.
Step 3— Pipet 1.00 ml standard N32C03, 4.00 ml 1.0 M KC1 , plus 36.00
ml C02~free deionized water into a clean, dry titration vessel. Add
a Teflon stir bar and stir at medium speed (no visible vortex).
Step 4 — Immerse the pH electrode and record the pH when a stable
reading is obtained.
Step 5--Add a known volume of the HC1 titrant and record the pH when a
stable reading is obtained. Use the following table as a guide to the
volume of titrant that should be added for each pH range:
pH
>7.5
4 to 7.5
Maximum Volume Increment
of HC1 Titrant (ml)
0.3
0.1
Continue the titration until the pH is less than 4. Obtain at least
seven data points in the range pH 4 to 7.
Step 6--Calculate Fj^ for each data pair (acid volume added, pH) with
pH in the range 4 to 7:
lb
-
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where
Fib
Vs
V
C
K
Gran function
initial sample volume (41.00 ml)
volume of HC1 added (mL)
N Na?C03/(2 x dilution factor)
10-P"
7.079 x 10~7 (25 °C, 0.1 ionic strength, Butler, 1982)
1.202 x 10"}J (25 °C, 0.1 ionic strength, Butler, 1982)
1.660 x 10"14 (25 °C, 0.1 ionic strength, Butler, 1982)
w
Step 7—Plot FIO versus V. Using the points on the linear portion of
the plot, perform a 1-inear regression of FI& on V to obtain the coef-
ficients of the line F^ = a + bY. The correlation coefficient should
exceed 0.999. If it does not, reexamine the plot to make sure only
points on the linear portion are used in the linear regression.
Step 8—Calculate the equivalence volume, VL by
YI = -a/b
then calculate the HC1 normality by
N Na2C03 x V Na2C03
NHC1 =
3.2.8.2
Step 9--Perform Steps 5 through 8 two more times. Calculate an average
NHCI and standard deviation. The RSD must be less than 2 percent. If
it is not, the entire standardization must be repeated until the RSD
is less than 2 percent.
The concentration of each new batch of HC1 titrant must be cross-checked
using the procedure described in Section 3.2.8.3.
Store HC1 titrant in a clean polyethylene bottle. Although the HC1
titrant is stable, it must be restandardized monthly.
NOTE: An example of an HC1 standardization is given in Appendix C,
Section 1.0.
Initial Standardization of NaOH Titrant with KHP--
Every batch of NaOH titrant is initially standardized against KHP (see
below) and the standardization is cross-checked against standardized
HC1 titrant (Section 3.2.8.3). Thereafter, it is restandardized daily
against the HC1 titrant (Section 3.2.8.4).
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Step l—Ueigh approximately 0.2 g KHP to the nearest 0.1 mg, dissolve
in water, then dilute to 1.000 L. Calculate the normality of the
solution by
wt. KHP
204.22
eq
Step 2—Calibrate the pH electrode and meter as recommended by the
manufacturer.
Step 3--Purge the titration vessel with C02-free nitrogen, then pipet
5.00 ml standard KHP solution, 2.00 ml 1.0 M KC1, and 18.00 nt C02~free
water into the vessel. Maintain a C02~free atmosphere above the sample
throughout the titration. Add a Teflon stir bar and stir at medium
speed (no visible vortex).
Step 4--Immerse the pH electrode and record the reading when it
stabilizes.
Step 5—Titrate with the 0.01N NaOH using the increments specified in
the table below. Record the volume and pH (when stable) between
additions. Continue the titration until the pH is greater
than 10. Obtain at least four data points in the pH range 5 to
7 and four data points in the pH range 7 to 10.
pH
<5
to 9
>9
Maximum Volume Increment of
NaOH Titrant (ml)
0.2
0.05
0.2
Step 6— Calculate F35 for each data pair (volume added, pH) that has a
pH between 5-10 pH units.
V)
VSC
2[H]
+2
(v + v)
CH+] -
K
w
where
s
V
C
CH+]
Gran function
initial sample volume (25.00 ml)
volume NaOH added (ml)
M KHP corrected for initial dilution = N KHP/5
= 1.3 x io
"3
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K2 = 3.9 x 10"6
Kw = 1.660 x 10"14
Step 7—Plot F3b versus V. Using the points on the linear portion of
the plot, perform a linear regression of F3t, on V to obtain the coef-
ficients of the line F^b = a + bV. The correlation coefficient should
exceed 0.999. If it does not, examine the plot to ensure that only
points on the linear portion are used in the linear regression.
Step 8—Calculate the equivalence volume, V3, by
V3 = -a/b
then calculate the NaOH normality by
MKHP x VKHP
NNaOH = "
Step 9--Perform Steps 5 through 8 two more times. Calculate an
average N^GH and standard deviation. The RSD must be less than 2
percent. If it is not, the entire standardization must be repeated
until the RSD is less than 2 percent.
NOTE: An example of an NaOH standardization is given in Appendix C,
Section 2.0.
3.2.8.3 NaOH-HCl Standardization Cross-Check--
Step I—Purge a titration vessel with C02~free nitrogen, then pipet
0.500 ml 0.01N NaOH, 2.50 ml 1.0 M KC1, and 22.00 nt C02-free water
into the vessel. Maintain a C02~free atmosphere above the sample.
Add a Teflon stir bar and stir at medium speed.
Step 2--Immerse the pH electrode and record the reading when it
stabilizes.
Step 3—Titrate with the standardized 0.01N HC1 using the increments
specified in the table below. Record the volume and pH (when stable)
between additions. Continue the titration until the pH is less than
3.5. Obtain at least seven data points in the pH range 4 to 10.
Maximum Volume Increment of
pH HC1 Titrant (ml)
>10 0.2
4 to 10 0.05
<4 0.2
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Step 4—Calculate F]_ for e'ach data pair (V, pH) that has a pH in the
range 4 to 10 by
K
= (V
V)
w
[H+]
- CH+]
where
CH+] =
Gran function
initial sample volume (25.0 ml)
volume of HC1 added (ml)
1.560 x 10"14
10-PH
Step 5--Plot FI versus V. Using the points on the linear portion of
the plot, perform a linear regression of FI on V to obtain the coef-
ficients of the line FI = a + bV. The correlation coefficient should
exceed 0.999. If it does not, reexamine the plot to ensure that only
points on the linear portion are used in the linear regression.
Step 6—Calculate the equivalence volume, Vj, by
Y! = -a/b
then calculate the HC1 normality (designated as N'HCI) bv
N>HC1 =
where
VNaOH = 0.500
Step 7—Calculate the absolute relative percent difference (RPO)
between N'^rj and
RPD =
N
x 100
The absolute RPO must be less than 5 percent. If it is not, a problem
exists in the acid or the base standardization or both (bad reagents,
out-of-calibration burets, etc.). The problem must be identified and
both procedures (standardization of HC1 titrant and standardization of
NaOH titrant) must be repeated until the RPD calculated above is less
than 5 percent.
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NOTE: An example of an NaOH-HCl Standardization Cross-Check is given
in Appendix C, Section 3.0.
3.2.8.4 Daily NaOH Standardization with Standardized HC1--
Step 1—Calibrate the pH meter and electrode as recommended by the
manufacturer.
Step 2—Purge the titration vessel with C02~free nitrogen, then pipet
0.500 ml NaOH titrant, 2.50 mL 1.0 M KC1, and 22.00 ml C02-free
deionized water into the vessel. Maintain a C02~free nitrogen atmos-
phere above the sample. (Smaller or larger volumes of NaOH may be
used. A known volume of C02~free water should be added to bring
solution to 25.00 mL). Add a Teflon stir bar and stir at medium
speed.
Step 3—Immerse the pH electrode and record the reading when it
stabilizes.
Step 4~Titrate with the standardized HC1 titrant using the increments
specified in the table below. Record the volume and pH between
additions. Continue the titration until the pH is less than 4.
Obtain at least seven data points in the pH range 4 to 10.
Maximum Volume Increment of
pH HC1 Titrant (ml)
>10 0.2
4 to 10 0.05
<4 0.2
Step 5—Calculate F^ for each data pair (volume acid added, pH) in
the pH range 4 to 10 by
where
FI = Gran function
Ys = initial sample volume (25.00 mL)
V = volume of HC1 added (mL)
Kw = 1.660 x 10'14
[H+] = 10-PH
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Step 5—Plot FI versus V. Using the points on the linear portion of
the plot, perform a linear regression of Fj on V to obtain the coef-
ficients of the line Fj. = a + bV. The correlation coefficient should
exceed 0.999. If it does not, reexamine the plot to make sure that
only points on the linear portion are used in the linear regression.
Step 7—Calculate the equivalence volume, Vj, by
V! = -a/b
then calculate the NaOH normality by
NNaOH =
vNaOH
Step 8--Perform Steps 4 through 7 two more times. Calculate an average
NfjaOH and standard deviation. The RSD must be less than 2 percent.
If it is not, the entire standardization must be repeated until the
RSD is less than 2 percent.
Because the NaOH titrant can deteriorate readily through exposure to
the air, every effort must be made to prevent its exposure to the air
at all times. Furthermore, it must be standardized daily or before
every .major work shift. Store in a linear polyethylene or Teflon
container with a C02~free atmosphere (e.g., under C02~free air, nitrogen,
or argon).
NOTE: An example of daily NaOH standardization is given in Appendix C,
Section 4.0.
3.2.8.5 Calibration and Characterization of Electrodes--
Separate electrodes must be used for the acid and base titration.
Each new electrode pair must be rigorously evaluated for Nernstian
response, using the rigorous calibration procedure described below,
prior to analyzing samples. After the initial electrode evaluation,
the electrodes are calibrated daily using the procedure in the daily
calibration procedure described below.
° Rigorous Calibration Procedure—This procedure calibrates and evalu-
ates the Nernstian response of an electrode. Also, it familiarizes
the analyst with the electrode's characteristic response time.
Step l--Following the manufacturer's instructions, calibrate the
electrode and meter used for acid titrations with pH 7 and 4 buffer
solutions, and calibrate the electrode used for base titrations with
pH 7 and 10 buffer solutions.
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Step 2--Prepare a blank solution by pipetting 45.00 ml C02~free water
and 5.0 mL of 1.0 M KC1 into a titration vessel. Ada a Teflon stir
bar and stir at medium speed using a magnetic stirrer.
Step 3—Titrate the blank with standardized 0.01N HC1 using the incre-
ments specified below. Continue the titration until the pH is in
the range 3.3 to 3.5. Record the pH between each addition, noting
the time required for stabilization. Obtain at least seven data
points that have a pH less than 4.
Maximum Volume Increment of
pH HC1 Titrant (ml)
>4 0.050
£4 0.3
Step 4—Prepare a fresh aliquot of water and 1.0 M KC1 as in Step 2.
Step 5—Under a C02~free atmosphere, titrate the blank with standard-
ized 0.01N NaOH using the increments specified as follows:
Maximum Volume Increment of
pH NaOH Titrant (ml)
<10 0.10
>10 0.20
Step 6—Continue the titration until the pH is in the range 10.5 to
11. Record the pH between each addition. Obtain at least 10 data
points between pH 9 and 10.5.
Step 7—For each titration, calculate the pH for each data point by
pH = -log [H+]
where for acid titration
VA CA
[Ht] = —» .
and for base titration
Kw
CH+] = i —r
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and where
VA = acid volume (mL)
CA = HC1 concentration (eq/L)
Vs = sample volume (50.0 mL)
Kw = 1.660 x 10"14
Vg = base volume (mL)
Cg = NaOH concentration (eq/L)
Step 8—For each titration, plot the measured pH versus the calculated
pH (designated as pH*). Perform a linear regression on each plot to
obtain the coefficients of the line pH = a + b(pH*). The plots must
be linear with b = 1.00 ± 0.05 and r > 0.999. Typically, some non-
linearity exists in the pH region 6 to 8. This is most likely due to
small errors in titrant standardization, impure salt solutions, or
atmospheric C02 contamination. The nonlinear points should not be
used in the linear regression.
If the plots are not linear and do not meet the specifications above,
the electrode should be considered suspect. The electrode character-
ization must be repeated then. If unacceptable results are still
obtained, the electrode must be replaced.
Step 9—Combine the data from both titrations and perform a linear
least-squares analysis on the combined data to obtain new estimates
for the coefficients of pH = a + b(pH*). The electrodes are now
calibrated. Do not move any controls on the meter.
The plots for both titrations should be coincident. If the two plots
are not coincident (i.e., the coefficients a and b do not overlap),
the characterization must be repeated. If the plots are still not
coincident, the electrode must be replaced.
Daily Calibration Procedure—Generally, the calibration curve prepared
during the rigorous calibration procedure is stable from day to day.
This daily calibration is designed to verify the calibration on a
day-to-day basis.
Step 1—Copiously rinse the electrode with water. Immerse the elec-
trode in 20 mL pH 7 buffer and stir for 1 to 2 minutes. Discard the
buffer and replace with 40 mL pH 7 buffer. "While the solution is
gently stirred, measure the pH. Adjust the pH meter calibration knob
until the pH is equal to the theoretical pH of the buffer. Record the
theoretical pH and the final, measured pH reading. The two values
should be identical.
Step 2—Copiously rinse the electrode with water. Immerse it in 20
mL pH 4 QC sample and stir for 1 to 2 minutes. Discard the sample and
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replace with 40 ml pH 4 QC sample. While the solution is stirred,
measure and record the pH. From the calibration curve of pH versus
pH*, determine the pH* for the observed pH. Compare pH* to the
theoretical pH of the QC sample. The two values must agree within
±0.05 pH unit. If the two values do not agree, the rigorous
calibration procedure must be performed prior to sample analysis.
Step 3--Repeat Step 2 with the pH 10 QC sample. This sample must be
kept under a C02~free atmosphere when in use, or acceptable results
may not be obtained.
An example of an electrode calibration is given in Section 5.0 of
Appendix C.
3.2.9 Quality Control
3.2.9.1 Duplicate Analysis--
Analyze one sample per batch in duplicate. The duplicate precision
(expressed as an RSD for ANC and BNC and standard deviation for pH)
must be less than or equal to 10 percent for ANC and BNC and 0.05
units for pH. If the duplicate precision is unacceptable (RSO >10
percent, SO >0.05), then a problem exists in the experimental tech-
nique. Determine and eliminate the cause of the poor precision prior
to continuing sample analysis.
3.2.9.2 Blank Analysis-
Determine the ANC in one blank per batch. The absolute value of the
ANC must be less than or equal to 10 ueq/L. If it is not, contamina-
tion is indicated. Determine and eliminate the contamination source
(often the source will be the water or the KC1) prior to continuing
sample analysis. An example of the determination of ANC in a blank
solution is presented in Appendix C, Section 6.0.
3.2.9.3 pH QCCS—
Prior to analysis of the first sample in a shift and every five
samples thereafter, the appropriate pH QC sample (pH 4 QC sample for
acid titrations and pH 10 QC sample for base titrations) must be
analyzed using the following procedure.
Copiously rinse the electrode with deionized water. Immerse it in 20
nt QC sample and stir it for 30 to 60 seconds". Discard the sample and
replace with an additional 40 ml QC sample. While the solution is
gently stirred, measure and record the pH. From the calibration curve
of pH versus pH*, determine the pH*. If the pH* and theoretical pH of
the QC sample differ by more than 0.05 pH unit, stop the analysis and
repeat the rigorous calibration procedure described in Section 3.2.8.5.
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Previously analyzed samples (up to the last acceptable QC sample) must
be reanalyzed. Acceptable values of pH* are reported on MSWS Form 20
(see Appendix B).
3.2.9.4 Comparison of Initial Titration pH Values--
The values for measured pH at Vtl-trant = 0 (before KC1 spike) of the
acid and base titrations should be within ±0.1 pH unit. If they are
not, check operation to ensure that cross-contamination is not
occurring.
For a sample with ANC <-15 ueq/L, calculate a value for ANC as follows:
[ANC]CQ = 106 x 10~PH* (pH at V = 0)
(The pH at Vt-jtrant = 0 is taken from the acid titration.) If ANC
differs from [ANClco by more than 10 ueq/L, check the electrode
operation and calibration.
3.2.9.5 Comparison of Calculated ANC and Measured ANC—
A value for ANC can be calculated from a sample's DIC concentration
and pH. Two sets of pH and DIC values are obtained in the lab: (1)
pH* at V = 0 of the base titration and the associated DIC concentra-
tion and (2) pH of the air-equilibrated sample and the associated DIC
concentration. Each set can be used to calculate a value for ANC.
ANC is a conservative parameter (i.e., constant with changing
dissolved COg concentrations); therefore, the two values should be
equal. The calculated values for ANC also can be compared to the
measured value of ANC. The comparisons are useful in checking Doth the
validity of assuming a carbonate system and the possibility of
analytical error. ANC is calculated from pH and DIC as follows:
= calculated ANC from initial pH and DIC at time of
base titration
calculated ANC from air-equilibrated pH and DIC
DIC / [H+]Ki + 2 K,K, \ K
^f^
[H+]
[ANC]C2
[ANC]C (ueq/L)
where
12,011 \[H+]2 + [H+lKj
x 10£
DIC
CH+]
K
1
DIC in mg/L (the factor 12,011 converts mg/L to moles/L)
IO-PH
7.0795 x 10"? at 25 °C, 0.1 M ionic strength
1.2023 x 10"10 at 25 °C, 0.1 M ionic strength
1.6596 x 10"14 at 25 °C, 0.1 M ionic strength
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[ANC]Q and [ANC](;2 are compared as follows:
For [ANCJd f 100 ueq/L, the following condition applies
CANC]C1 - [ANC]C2
< 15 ueq/L
For [ANClci >100 peq/L, the following condition applies
[ANC]C1 - [ANC]C2
(CANC]C1 + [ANC]C2)/2
x 100
< 10%
If either condition is violated, a problem is indicated in either the
pH and/or the DIG determination. In such cases, the problem must be
found, corrected, and the samples reanalyzed.
It is very important that the pH and DIG be measured as closely
together in time as possible. If they are not measured closely in
time, acceptable agreement between [ANClci and [ANC](;2 may not be
obtained.
When acceptable values for [ANClci and [ANCJC2 are obtained, their
average is compared to the measured ANC as described below.
For [ANC]r-avg 1 100 neq/L, the difference "D" and the acceptance
window "w1 are
D = [ANC]c_avg - ANC and w = 15
For [ANC]c_avg > 100 ueq/L,
[ANC]c_avg - ANC
D = x 100 and w = 10?
CANClc-avg
If |D| <_ w, it is valid to assume a carbonate system. If D < -w then
the assumption of a pure carbonate system is not valid and the sample
contains noncarbonate protolytes (soluble reacting species), such as
organic species. If 0 > w, an analytical problem exists in the pH
determination, DIG determination, Gran analysis calculation, or acid
titration (such as titrant concentration). In this case, the proolem
must be identified and the sample must be reanalyzed.
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3.2.9.6 Comparison of Calculated BNC and Measured BNC—
Just as for ANC, pH and DIG values can be used to calculate a BNC
value. Because the BNC of a sample changes with changing dissolved
C02 concentration, only the initial pH and DIG values measured at the
beginning of the base titration are used to calculate a BNC value.
This calculated BNC is compared to the measured BNC value. BNC is
calculated by [BNC]C (ueq/L) =
'DIG / [H+]2 - KiK2 \ K 1
-T5—+ + CH+]' "r x 10
12,011 \[H+]2 + [H+]K1 + K^ / CH+]
is compared to BNC as described below.
For [BNC]C <_ 100 ueq/L,
D = [BNC]C - BNC and w = 10 ueq/L
For [BNC]C > 100 ueq/L,
[BNC]C - BNC
0 = x 100 and w = 10%
[BNC]C
If |D| <_ w, then it is valid to assume a carbonate system. If D < -w,
the assumption of a pure carbonate system is not valid, and the sample
contains noncarbonate protolytes, such as organic species.
If D > w, an analytical problem exists in the pH determination, DIC
determination, Gran analysis calculation, or base titration (such as
titrant concentration). In this case, the problem must be identified
and the sample must be reanalyzed.
3.2.9.7 Comparison of Calculated Total Carbonate and Measured Total Carbonate--
If the assumption of a carbonate system is valid, the sum of ANC plus
BNC is equal to the total carbonate. This assumption can be checked
by calculating the total carbonate from the sum of [ANC]C and [BNC]C,
then comparing the calculated total carbonate to the measured estimate
of total carbonate (the sum of ANC plus BNC). The total carbonate is
calculated (Cr,) by
CC (umole/L) = [ANC]c-avg + [BNC]C
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GC is compared to (ANC + BNC) as follows:
For GC £ 100 umole/L, then
D = GC - (ANC + BNC) and w = 10 (.imole/L
For GC > 100 |jmole/L, then
Cc - (ANC + BNC)
D = - x 100 and w = 10%
CC
If |D| _< w, the assumption of a carbonate system is valid. If D < -w,
the assumption is not valid and the sample contains noncarbonate
protolytes. If 0 > w, an analytical problem exists. It must be
identified and the sample must be reanalyzed.
3.2.10 Procedure
An acid titration (Section 3.2.10.1) and a base titration (Section
3.2.10.2) are necessary to determine the BNC and ANC of a sample. As
part of each titration, the sample pH is determined. The air-
equilibrated pH is determined in a separate sample portion (Section
3.2.10.3).
3.2.10.1 Acid Titration—
Step I—Allow a sealed lake sample (aliquot 5) to reach ambient
temperature.
Step 2— Copiously rinse the electrode with deionized water, then
immerse in 10 to 20 ml sample. Stir for 30 to 60 seconds.
Step 3— Pipet 36.00 ml sample into a clean, dry titration flask. Add
a clean Teflon stir bar and place flask on a magnetic stirrer. Stir
at medium speed (no visible vortex).
Step 4 — Immerse the pH electrode and read pH. Record pH on Forms 11
and 13 (Appendix B) when the reading stabilizes (1 to 2 minutes).
This is the initial measured pH at Vtl-trarit = 0.
Step 5— Add 4.00 ml 1.0 M KC1 . Read pH and record the value on Form
13. This is the initial measured pH at Vtitrant = ° after addition
of KC1 spike.
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Step 6--Add increments of 0.01N HC1 as specified in the table below.
Record the volume of HC1 added, and record the pH when a stable
reading is obtained. Adjust the volume increment of titrant so that
readings can be taken at pH values of 4.5 and 4.2. Continue the
titration until the pH is between 3.3 and 3.5. Obtain at least six
data points between a pH of 4.5 and 5.5 and at least six that have a
pH less than 4.
Maximum Volume Increment of
pH HC1 Titrant (ml)
>9 0.1
7.0 to -9.0 0.025
5.5 to 7.0 0.1
4.5 to 5.5 0.05
4.50 to 3.75 0.1
<3.75 0.3
3.2.10.2 Base Titration--
Step I—Take a portion of aliquot 5 for DIG determination. If the
DIG is not determined immediately, the sample must be kept sealed
from the atmosphere and stored at 4 °C. A simple way to do this is
to withdraw the sample for DIG using a syringe equipped with a
syringe valve. By closing the valve, the sample is sealed from the
atmosphere (syringe valves that fit standard Luer-Lok syringes are
available from most chromatography supply companies).
Step 2--Purge the titration vessel with C02~free air, nitrogen, or
argon.
Step 3--Copiously rinse the electrode with deionized water, then
immerse it in 10 to 20 ml sample for 30 to 60 seconds.
Step 4~Pipet 36.00 ml sample into the C02-free titration vessel.
Maintain a C02~free atmosphere above the sample. Do not bubble the
nitrogen (or other C02~free gas) through the sample. Add a clean
Teflon stir bar and place on a magnetic stirrer. Stir at medium
speed (no visible vortex).
Step 5—Immerse the pH electrode, read pH, an0 record pH on Forms 11
and 13 when pH stabilizes. This is the initial measured pH at
vtitrant = °-
Step 6—Add 4.0 mL 1.0 M KC1. Read and record pH on Form 13.
Step 7—Add 0.025 mL of 0.01N NaOH. Record the NaOH volume and pH
when it stabilizes. Continue the titration by adding increments of
NaOH as specified below until the pH is greater than 11. Record the
volume of NaOH added and the pH after each addition. Obtain at least
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6 data points in the pH region 7 to 9 and at least 6 with a pH
greater than 10. If the initial sample pH is less than 7, obtain at
least five data points below pH 8.
Maximum Volume Increment of
pH NaOH Titrant (ml)
<5 0.025
5 to 7 0.050
7 to 9 0.025
9 to 10 0.10
10 to 10.5 0.30
>10.5 1.00
3.2.10.3 Air-Equilibrated pH Measurement-
Step I—Allow the sealed sample (aliquot 5) to reach ambient
temperature.
Step 2—Copiously rinse the electrode with deionized water, then
immerse in 10 to 20 ml sample. Stir for 30 to 60 seconds.
Step 3—Plpet 20 to 40 ml sample into a clean, dry titration flask.
Add a clean Teflon stir bar and place flask on a magnetic stirrer.
Stir at a medium speed.
Step 4—Bubble standard gas containing 300 ppm C0£ through the sample
for 20 minutes. Raise gas tube above liquid surface to maintain
atmosphere above sample. Measure and record the pH.
Step 5—While maintaining 300 ppm C02 atmosphere, take a subsample
for DIG determination. The subsample must be kept sealed from the
atmosphere prior to analysis. The DIG should be measured as soon as
possible.
3.2.11 Calculations
During the titrations, any substance which reacts with the acid or base
is titrated. However, for calculations, it is assumed that the samples
represent carbonate systems and that the only reacting species are If",
OH~, H2C03, HC03~, and C032~. Using this assumption, the two parameters
"ANC" TANC) and "C02-BNC" (BNC) are calculated. The validity of the
assumption is checked as described in previous sections.
The theory behind the calculations is available elsewhere (Kramer, 1982;
Butler, 1982; Kramer, 1984). Examples of the calculations are given in
Appendix C.
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3.2.11.1 Initial Calculations-
Step I—From the calibration curve of measured pH versus calculated
pH (pH*), determine pH* for each pH value obtained during both the
acid and base titrations. Next, convert all pH* values to hydrogen
ion concentrations by
[H+] = 10-PH*
Step 2— Using the acid titration data, calculate the Gran function
for each data pair (Va, pH*) in which pH* is less than 4 by
Fla = (Vs + Va) [H+]
where
Vs = total initial sample volume (36.00 + 4.00)mL
V = cumulative volume of acid titrant added
Step 3— Plot Fia versus Va. The data should be on a straight line
with the equation Fia = a + bV.
Step 4 — Perform a linear regression of F^a on Va to determine the
correlation coefficient (r) and the coefficients a and b. The coef-
ficient r should exceed 0.999. If it does not, examine the data to
ensure that only data on the linear portion of the plot were used in
the regression. If any outliers are detected, repeat the regression
analysis. Calculate an initial estimate of the equivalence volume
(Vi) by
V! = -a/b
Further calculations are based on this initial estimate of V^ and the
initial sample pH*. Table 3-11 lists the appropriate calculation
procedure for the different combinations of YI and initial sample pH*.
NOTE: For blank analyses, calculate ANC by ANC = Vx Ca/Vsa
where
Ca = concentration of acid titrant .
Vsa = original sample volume (acicT titration)
Further calculations are not necessary.
Throughout the calculations, equations 3-1 and 3-2, as well as the
constants listed in Table 3-12, are used frequently.
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TABLE 3-11. CALCULATION PROCEDURES FOR COMBINATIONS OF INITIAL Vj AND pH*
Sample Descri ptl o n
Initial
Initial pH*a
Calculation
Procedure
Section No.
<0
>0
>0
>PHe2
A
B
C
3.2.11.2
3.2.11.3
3.2.11.4
JpHe2 is calculated using equation 3-4.
Equ. 3-1
(V + V)
C([H+]Ki
[H
+2
Equ. 3-2 F2c = (Ys + V)
C([H+]2 -
[H+]
•M2
Equ. 3-3
pHei = -
Hel '
(DIC)K
12,011
1/2
Equ. 3-4
pHe2 = -log(He2)
He2 =
12,011\
DIC
1/2
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TABLE 3-12. CONSTANTS AND VARIABLE DESCRIPTIONS
Vs = total initial sample volume
• V = cumulative volume of titrant added
C = total carbonate expressed in moles/L
[H+] = hydrogen ion concentration
Kj = 7.079 x 10"7 at 25 °C and 0.1 M ionic strength (Butler, 1982)
K2 = 1.202 x 10"10 at 25 °C and 0.1 M ionic strength
3-14
Kw = 1.660 x 10"14 at 25 °C and 0.1 M ionic strength
3.2.11.2 Calculation Procedure A (Initial Vj < 0)—
Step 1— From the base titration data, determine which data set (V,
pH*) has the pH* nearest (but not exceeding) pH62 (calculate using
Equation 3-4). As an initial estimate, set the equivalence volume
V2 equal to the volume recorded for this data set.
Step 2— Calculate initial estimates of ANC, BNC, and C by
ANC =
Vsa
BNC =
Vsb
C = ANC + BNC
where
Ca = concentration of acid titrant
Vsa = original sample volume (acid titration)
Cb = concentration of base titrant
vsb = original sample volume (base titration)
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Step 3—Estimate the equivalence point pHej using Equation 3-3.
Calculate the Gran function FIC for seven to eight points of the base
titration with pH* spanning pHei using Equation 3-1. Plot FIC versus
Vfc. Perform a linear regression with the points lying on the linear
portion of the plot. Determine the coefficients of the line FIC =
a + bV. The coefficient r should exceed 0.999. If it does not,
examine the plot to ensure that only points on the linear portion are
used. From the coefficients, calculate a new estimate of Vj by
Vj = -a/b
Step 4—Calculate the Gran function F2C (Equation 3-2) for data from
the base titration across the current estimate of V£. (Use the first
four to six sets that have a volume less than V2 and the first six to
eight sets that have a volume greater than V2-) Plot F2C versus V&.
The data should lie on a straight line with the equation F2C = a + bV.
Perform a linear regression of F2C on V& and determine the coefficients
of the line.
If r does not exceed 0.999, reexamine the data to ensure that only
points on the linear portion were used in the regression. Calculate
a new estimate of V2 by
V2 = -a/b
Step 5—Calculate new estimates of ANC, BNC, and C using the new
estimates of Vj and V2 (an asterisk indicates a new value).
BNC* =
Vsb
C* = ANC + BNC
If C* < 0, then set C* = 0.
Step 6—Compare the latest two values for total carbonate. If
C - C*|
> 0.001
C + C*
then calculate a new estimate for C by
C(new) = (C + C*)/2
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Step 7 — Using the new value for C, repeat the calculations as above.
Continue repeating the calculations until the relative difference
between C and C* is less than 0.001.
Step 8 — When the expression is less than 0.001, convert the final
values for ANC, BNC, and C to ueq/L by
ANC (ueq/L) = ANC (eq/L) x 106
BNC (uea/L) = BNC (ea/L) x 106
C (ueq/L) = C (eq/L) x 106
3.2.11.3 Calculation Procedure B (Initial Vj _> 0, Initial pH* <_ pH62)~
Step l--From the base titration data, determine which data set (V,
pH*) has the pH* nearest, but not exceeding, pH62 (calculate using
Equation 3-4). As an initial estimate, set the equivalence volume
equal to the volume recorded for this data set. Next calculate
initial estimates of ANC, BNC, and C by
ANC =
BNC =
C = ANC + BNC
Step 2--Calculate the Gran function FIC (Equation 3-1) for data
sets from the acid titration with volumes across the current estimate
of YI (use the first tour to six sets with volumes less than Vj and
the first six to eight sets with volumes greater than Vj). Plot FIC
versus Va. The data should lie on a straight line with the equation
FIC = a + bV. Perform a linear regression of. FIC on Va and determine
the coefficients of the line.
Step 3 — If r does not exceed 0.999, reexamine the data to ensure that
no outliers were used in the regression. Calculate a new estimate
for YI by
Y = -a/b
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Step 4--Calcu1ate the Gran function F2C (Equation 3-2) tor data sets
from the base titration with volumes across the current estimate of V2.
(Use the first four to six sets with volumes less than V2 and the
first six to eight sets with volumes greater than V£). Plot F2C versus
Vfc. The data should lie on a straight line with the equation F2C = a
+ bV. Perform a linear regression of ?2c on ^b and determine the
coefficients of the line. If r does not exceed 0.999, reexamine the
data to ensure that only data on the linear portion were included in
the regression. Calculate a new estimate for V2 by
V2 = -a/b
Step 5—Calculate new estimates of ANC, BNC, and C using the latest
estimates of Vj and V2-
C* = ANC + BNC
Step 6~Compare the latest two values for total carbonate. If
> 0.001
then calculate a new estimate of C by
C(new) = (C + C*)/2
Step 7--Using the new value of C, repeat the calculations as above.
Continue repeating the calculations until the above expression is
less than 0.001.
Step 8—When the expression is less than 0.001, convert the final
values for ANC, BNC, and C to ueo/L by
ANC (ueq/L) = ANC (eq/L) x 106
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BNC (ueq/L) = BNC (eq/L) x 106
C (ueq/L) = C (eq/L) x 106
3.2.11.4 Calculation Procedure C (Initial Vj > 0, Initial pH* > pH62)--
Step 1—Using data sets from the acicf titration with pH* values
above and below pH 7 (use four to six sets with a pH* <7 and four to
six sets with a pH* _>7), calculate the Gran function F2a by
F2a = (Vi - Va)H
Step 2~Plot F2a versus Va. The data should lie on a straight line
with the equation F2a = a + bV. Perform a linear regression of
on Va. The coefficient r should exceed 0.999. If it does not,
reexamine the plot to ensure that only data on the linear portion
were used in the calculation. Calculate an estimate for V2 by
V2 = -a/b
Step 3--Calculate estimates of ANC, BNC, and C by
ANC =
Vsa
C = ANC + BNC
Step 4--Calculate the Gran function FIC (Equation 3-1) for data sets
from the acid titration with volumes across the current estimate of
Y! (use the first four to six sets with volumes less than Vj and the
first six to eight sets with volumes greater than Vj). Plot Fjc
versus Va. The data should lie on a straight line with the equation
FIC = a + bV. Perform a linear regression of.F]_c on Va and determine
the coefficients of the line. The coefficient r should exceed 0.999.
If it does not, reexamine the plot to ensure that only data on the
linear portion were included in the regression. Calculate a new
estimate for Vj by YI = -a/b.
Step 5— Calculate the Gran function F2C (Equation 3-2) for data
sets from the acid titration with volumes across the current estimate
of V2 (use the first four to six sets with volumes less than V2 and
the first six to eight sets with volumes greater than V2). Plot
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versus Va. The data should lie on a straight line with the equation
?2c = a + bV. Perform a linear regression of F2C on Va and determine
the coefficients of the line. The coefficient r should exceed 0.999.
If it does not, reexamine the plot to ensure that only data on the
linear portion were included in the regression. Calculate a new
estimate of ^2 by ^2 = ~a/b.
If V2 < 0, use calculation procedure B (Section 3.2.11.3).
Step 6~Calculate new estimates of ANC, BNC, and C using the latest
estimates of V^ and V2-
ANC* =
Vsa
-v2ca
BNC* =
Vsa
C* = ANC + BNC
Compare the latest two values for total carbonate. If
> 0.001
then calculate a new estimate of C by
C(new) = (C + C*)/2
Using this new value of C, repeat the calculations in Section
3.2.11.4, Steps 2 through 4. Continue repeating the calculations
until the above expression is less than 0.001.
When the expression is less than 0.001, convert the final values for
ANC, BNC, and C to ueq/L by
ANC (ueq/L) = ANC (eq/L) x 106
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3NC (ueq/L) = 8NC (eq/L) x 10°
C (ueq/L) = C (eq/L) x 106
3.3 DETERMINATION OF AMMONIUM
The ammonium determination is performed using the same procedure that was
used during ELS-I. For a discussion of the method, see Hillman et al.
(1986).
3.4 DETERMINATION OF CHLORIDE, NITRATE, AND SULFATE
The determination of chloride, nitrate, and sulfate ion concentrations is
performed using the same procedure that was used during ELS-I. For a
discussion of the method, see Hillman et al. (1986).
3.5 DETERMINATION OF CHLOROPHYLL a_
Determination of chlorophyll £ is a new procedure that was not used
during ELS-I. The procedure Ts applied to surface water samples.
3.5.1 Scope and Application
This procedure is applicable to the determination of chlorophyll £ and
pheophytin ^concentrations in natural waters of low ionic strength.
Chlorophyll a_is one of several chlorophylls found in planktonic algae
and is commonly measured as an indicator of algal biomass (Shelske,
1984).
3.5.2 Summary of Method
Surface water samples are filtered in the field, and the phytoplankton
retained on a polycarbonate filter are shipped to the mobile processing
facility, where the samples are held temporarily and are shipped in
weekly batches to the analytical laboratory. At the analytical labora-
tory, the filters are extracted at 4 °C with 95 percent methanol. The
fluorescence intensity of the extracted pigments at 660 nm is measured
and is compared to the measured intensities of chlorophyll £ standards
(Stainton et al., 1977). The extract is analyzed then by reverse-phase,
high-performance liquid chromatography (HPLC) with fluorescence detec-
tion to allow differentiation between fluorescence from chlorophyll a_
and from other pigments that fluoresce at 660 nm (Reibiz et al., 1978).
3.5.3 Interferences
With the fluorometer settings recommended, the instrument responds to
chlorophyll a in the extract (Stainton, et al., 1977). However, pheo-
phytin a^ chlorophyll b_, pheophytin ]>, and other common pigments also
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tluoresce at 660 nm, resulting in an overestimate of chlorophyll a
(Holm-Hansen ana Riemann, 1978). HPLC analysis of the extract allows
measurement of tne exact amounts of chlorophyll £ and pheophytin a.
3.5.4 Safety
Diethyl ether can form potentially explosive peroxides when stored;
this can be avoided by storage over a sodium alloy (e.g., Dri-Na).
Diethyl ether and dimethyl amine are very volatile, and along with ethyl
acetate, hexane, and methanol, are extremely flammable (NIOSH/OSHA,
1977; Muir, 1980). All work with these compounds should be performed
in a fume hood. Dimethylamine is highly toxic; respirators should be
worn if ambient concentrations are above 10 ppm. If dimethylamine is
used outside a fume hood, laboratory air concentrations and personnel
exposure should be monitored (NIOSH, 1977).
Analysts should be careful when handling concentrated acids. Eye
protection should be worn, and work must be carried out in a fume hood.
Caution should be exercised to ensure that centrifuges and centrifuge
heads are firmly fastened and are stable.
3.5.5 Apparatus and Equipment
° Centrifuge, slant-head.
° Centrifuge tubes—15-mL, graduated, with screw cap.
° Developing chamber for thin-layer chromatograph.
° Filtration equipment—filters, funnels, filtration flask, vacuum
source.
° High performance liquid chromatograph, including:
Fluorescence detector: Excitation filter - 430-470 nm,
Emission filter - 650-675 nm, blue source
Rheodyne sampling valve, with 10-25 uL sampling loop
HPLC pumping system, dual piston, constant flow, capable of 2.0 to
3.0 mL/min at 150 bar
Integratoi—Hewlett Packard 3290 or equivalent
Reverse-phase HPLC column—5 micron Spheracil, 250 mm x 2.6 mm
I.D., or equivalent
Guard column—Waters C-18 Guard-Pak, or equivalent
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Spectrophotometer—Hewlett Packard 8450 photodiode array with flow
cell or equivalent, immediately downstream of the fluorescence
detector
° Turner Model III fluorometer, equipped as follows:
Cuvettes, 1 cm
Door with standard cuvette holder
Excitation filter—Kodak Wratten No. 478 (430-450 nm)
Emmission filtei—Corning S2-64 (650-675 nm)
° Spectrophotometei—for use at 650, 666, and 700 nm, with a spectral
resolution of 2 nm or less and wavelength precision of ±0.05 nm.
° Syringes—Hamilton 1710, or equivalent.
° Vials, with Teflon-lined screw-cap, 10-mL (or greater) capacity.
3.5.6 Reagents and Consumable Materials
8 Acetone--HPLC grade.
• Chlorophyll a—Chlorophyll ^extracted from Anacystis niulans is
free of chlorophyll j). Spinach, which contains mainly chlorophyll
£ and some chlorophyll b_, is available from Sigma Chemical Company,
St. Louis, Missouri. Chlorophyll also can be extracted from pale
green head-lettuce leaves, spinach, or grasses. Chlorophyll a_ can be
isolated from extracts by thin-layer chromatographic techniques
(Loftus and Carpenter, 1971). The extract, in a mixture of 95 percent
methanol and 10 percent NaCl (aq) (50/50, v/v), is extracted with
petroleum ether. The organic phase is freed of water by centrifuga-
tion and is evaporated to near dryness under a stream of nitrogen.
The remaining solution is spotted on an Eastman 6061 silica-gel
chromatogram sheet (previously dried at 50 °C for 30 minutes). The
chromatogram is developed with 58:30:12 hexane:ethy1acetate:dimethyl-
amine. Chlorophyll a_ (Rf = 0.74) and chlorophyll ]> (Rf = 0.71) spots
are cut out and are extracted into acetone. Store all chlorophyll
standards in the dark at -20 °C.
° Chlorophyll Ib—Chlorophyll b can be purchased from Sigma Chemical
Company, St. Louis, Missouri", as a crystalline solid. Chlorophyll b^
also can be isolated by the thin-layer chromatographic techniques
described above (Loftus and Carpenter, 1971).
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° Dimethyl amine--HPLC Grade.
° Ethyl Acetate—HPLC Grade.
o Hexane--HPLC Grade.
0 Hydrochloric acid, 0.12 M—Add 1 volume concentrated HC1 to 100
volumes Type I water (ASTM, 1984).
0 Methanol--HPLC grade.
0 Methanol, 95% (v/v)—Add 5 volumes Type I water (ASTM, 1984) to 95
volumes methanol. Mix well.
° Mobile phase for HPLC—Methanol:acetone:water, 68:27:5 by volume.
Store over magnesium carbonate tightly capped in a cool, well-
ventilated place. Do not allow prepared mixtures to evaporate.
0 Nitrogen--High purity.
° Petroleum Ethei—ACS reagent grade.
° Silica-Gel Chromatography Papei—Eastman 6061.
° Sodium Chloride—ACS reagent grade.
° Watei—Water used for preparations must conform to the standards for
Type I reagent water as specified in ASTM D 1193 (ASTM, 1984).
3.5.7 Calibration
3.5.7.1 HPLC—
Liquid chromatograph operating parameters listed below, or ones which
give resolution equivalent to that shown in Figure 3-1, must be used.
Column: Reverse-phase C^g, 5 um
Mobile Phase: Methanol :acetone:water, 68:27:5
(volume)
Detector: Fluorescence
Wavelengths: 440 nm (ex), 660 nm (em)
Flow Rate: 2.0 mL/min
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Figure 3-1. Examole HPLC chromatogram.
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'.feign out approximately 1 mg chlorophyll a. Dissolve the weighed
chlorophyll a_ in 50 mL 95-percent methanoT in a stoppered glass bottle
which is wrapped in aluminum foil to prevent exposure of the solution
to light. Handle the stock standard solution with care at all times,
and keep it cold (-10 °C) and in the dark when not in use. Exposure
to acid vapors must be avoided.
Measure the absorbances of the stock standard in a l-cm cuvette at
650, 666, and 700 nm with a l-cm cuvette of 95-percent methanol in
the reference beam. Subtract the absorbance at 700 nm from those at
650 nm and 666 nm to obtain values corrected for nonspecific light
losses (e.g., scattering from turbidity). Using these corrected
values, calculate the chlorophyll a_ and chlorophyll ^concentrations
in the solution.
Chlorophyll a_ (mg/L) = 16.5 Aeee ~ 8-3 A650
Chlorophyll b_ (mg/L) = 33.8 ^50 ~ 12-5 A666
If the concentration of chlorophyll b_ is greater than 5 percent of
that of chlorophyll &, another source of chlorophyll should be used.
Use the procedure described below to prepare mixed calibration
standards of chlorophyll £ and pheophytin £ from the chlorophyll £
stock solution at five concentrations spanning the range of 50.0 to
1,000 ug/L.
NOTE: Prepare all chlorophyll standards under subdued light and store
them in the dark.
Add a known volume of the chlorophyll a^ stock solution to a volumetric
flask. Add 10 percent of that volume of 0.12 M HC1 to the flask.
Swirl the mixture and allow it to stand for 5 minutes. Add 25 mg
magnesium carbonate per milliliter of solution and swirl to mix well.
After 10 minutes, add another measured volume of chlorophyll £ stock
solution equal to approximately 50 percent of the first volume. Fill
the volumetric flask to 75 percent of its volume with HPLC mobile
phase. Mix the solution well by inverting the stoppered flask 10
times. Dilute the solution quantitatively and mix well again. Allow
the magnesium carbonate to settle or filter the solution in the dark.
Analyze each calibration standard by injecting a volume through a
nylon sample preparation filter into the HPLC injection loop and
injecting it on column (50-uL injections). Tabulate the peak areas
of chlorophyll a_ and pheophytin a_. Use these results to prepare
calibration functions for chlorophyll a and pheophytin a_. If the
calibration curve is linear (r >_ 0.99 Tor a linear regression of area
on concentration), the mean response factor may be used.
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Repeat the caibration each working day using a freshly quantitated
stock solution. If the response for chlorophyll £ or pheophytin £
varies from the expected response by more than 10 percent, prepare
fresh stock standards and repeat the calibration.
3.5.7.2 Fluorometry--
Use the stock standard described above and 95 percent methanol to
prepare working standards of chlorophyll a_ in volumetric flasks
wrapped in aluminum foil. Use syringes, not air-displacement micro-
pi pets, to measure uL volumes. At least three calibration points
should be used for each of the four fluorometer sensitivity ranges
(IX, 3X, 10X, 30X1. The fluorometer should be zeroed against solvent
each time there is a scale change.
Possible dilutions to be used are given in Table 3-13. It is recom-
mended to choose standard concentrations which allow measurement of
the instrument response to individual standards on as many scales as
possible.
TABLE 3-13. DILUTIONS OF CHLOROPHYLL a_ STOCK STANDARD TO MAKE WORKING STANDARDS3
Working Volume of Concentration (ug/L)
Standard No. Stock Standard (X = stock standard cone, in mg/L)
Blank
1
2
3
4
5
6
7
8
9
10
11
12
OuL
50uL
lOOuL
150uL
200uL
300uL
500uL
l.OOmL
2.00mL
3.00mL
5.00mL
lO.OOmL
20.00mL
0
0.5 X
1.0 X
0.5 X
2.0 X
3.0 X
5.0 X
10 X
20 X
30 X
50 X
100 X
200 X
a cr
For each standard, final volume is 100 mL.
Measure the fluorescence intensity of standard solutions at 660 nm
(Stainton, et al., 1977; Baker, et al., 1983). Prepare intermediate
and additional dilutions as necessary to have three readings for each
sensitivity setting (IX, 3X, 10X, 30X). Because of the differences
in sensitivity between individual fluorometers, no concentrations
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that will work with all instruments can be specified here. Plot the
scale readings of the chlorophyll £ concentration for each sensitivity
factor; if the plot is linear (r >_~0.99 for linear regression), the
mean scale factor (slope) for each sensitivity setting may be used.
Chlorophyll a_ (ug/L)
F(1X, 3X, 10X, 30X) =
Scale Reading
On some fluorometers there will be curvature for high readings on the
IX sensitivity plot. Although the fluorometer calibration is rela-
tively stable, the calibration should be checked daily. A change in
instrument response of 10 percent or greater necessitates recalibra-
tion as described in Section 2.11.9.2. The fluorometer must be
recalibrated after maintenance, repair, and any changes in
configuration.
3.5.8 Quality Control
3.5.8.1 HPLC Analysis—
Before processing any samples, demonstrate through analysis of a
95 percent methanol blank that interferences from glassware and
reagents are under control.
From 10 sequential analyses of the methanol blank, calculate the MDL
using the standard deviation (SO) of the detector signal at the
retention time of interest:
MDL (ug/L) = 3 x SD
Calibrate the instrument at the start of each working day. In addi-
tion, analyze one calibration standard after every 5 samples; if the
mean response changes by more than 10 percent from the initial cali-
bration, evaluate the response with another standard or recalibrate
the instrument. Because the distribution of the HPLC response is not
known, the interim acceptance criterion of 10 percent has been set,
pending availability of better method-performance data.
Confirm the identity of the peaks in HPLC standards with retention
times corresponding to the phytopigments of interest by evaluating
the absorption spectrum from the photodiode array detector located
immediately downstream from the fluorescence detector. Perform the
spectral measurement every 2 seconds.
In addition, process a blank daily. A (double-blind) audit sample
will be included with each set of 20 or fewer samples. Results from
this sample will be evaluated to estimate the relative bias of the
measurements. Analyze one extract from each set of 20 or fewer
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samples in duplicate. A record of the precision of these duplicate
measurements should be maintained by the laboratory as a check on
analytical precision.
Periodically, extracts of phytopigments will be analyzed as a check
on the accuracy of HPLC determinations.
The QC results for the HPLC analyses are recorded on NSWS Form 33,
QC Results - Phytopigments - HPLC and on NSWS Form 34, QC Results -
Phytopigments - Time Line (Appendix 3).
3.5.8.2 Fluorometry—
Before analysis of any extracts, make 10 sequential measurements of
the fluorescence intensity of a 95 percent methanol reagent blank.
From the estimated standard deviation (SO) of these results, calculate
the method detection limit (MDL) by
MDL = 3 x SD
In addition, on each working day, or with each batch of 15 or fewer
samples, analyze a blank before processing any samples. If the
result of the blank analysis is above the MDL, evaluate the system
for possible sources of contamination.
As a check on instrument response, analyze one or more calibration
standards each working day before processing any samples. If the
response changes by more than 10 percent from the initial calibration,
analyze other standards as a check on the stability of the response.
A change of 10 percent or more in instrument response requires recall -
bration and analysis of two standards each day from that time forward.
Because the exact distribution of the instrument response factor is
not known, acceptance of variation less than or equal to 10 percent
has been set pending better description of method performance. With
each batch of samples, one audit sample will be included as a (double-
blind) check on combined extraction and analysis relative bias.
Analyze one extract from each batch in duplicate. A record of pre-
cision of duplicate measurements should be maintained by the labora-
tory as a check on analytical precision.
The QC results for fluorometry are recorded on NSWS Form 32, QC
Results - Phytopigments - Fluorometry, and on NSWS Form 34, QC
Results - Phytopigments - Time Line (Appendix B).
3.5.9 Procedure
3.5.9.1 Sample Extraction--
NOTE: Perform sample-handling procedures under subdued light.
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Place the filter from the field in a 10-mL screw-cap vial. Add a
measured volume (3 to 5 ml) of 95 percent (v/v) methanol to the vial
to cover the filter and tightly screw on the cap (with Teflon liner).
Record the volume to the nearest 0.1 ml. Allow the mixture to stand
for 1 hour at 4 °C in the dark, inverting it at 15-minute intervals.
After 1 hour, decant the methanolic solution from the vial; filtra-
tion or centrifugation of the mixture may be necessary. Store the
extract in the dark pending fluorometric and HPLC analysis.
3.5.9.2 Analysis—
From each set of 20 or fewer samples, divide one sample extract into
two aliquots and process the two in parallel. Perform the HPLC anal-
ysis before the measurement of extract gross fluorescence. Record
analytical results for all samples on NSWS Form 31, Summary of
Analytical Results - Phytopigments.
3.5.10 Calculations
Calculate the chlorophyll £ and pheophytin £ concentrations from the
HPLC analyses by use of the mean response factor or calibration
function (see Section 2.11.8). Calculate the total fluorescence by
using the chlorophyll £ mean response factor or calibration curve and
the total area of the chromatogram. Report results on NSWS Form 31,
Summary of Analytical Results - Phytopigments (Appendix 8), as chloro-
phyll £ (ug/L), pheophytin £ (ug/L), and total fluorescence (ug/L
chlorophyll £ equivalents).
Calculate the concentration of chlorophyll £ (from fluorometry) by
using the appropriate scale factor (see Section 2.11.8). Report
results as chlorophyll £ (ug/L uncorrected, fluorometric).
3.5.11 Precision and Accuracy
Although these methods have been used in limnological studies, they
are still in development, and method performances are not well
described. Loftus and Carpenter (1971) report a detection limit of
approximately 0.1 ug/L for a fluorometric method. However, the MDL
will depend on the size of the sample filtered (Holm-Hansen and
Riemann, 1978). The HPLC method is estimated to have a detection
limit of 0.2 M9 chlorophyll £ on the filter.
3.6 DETERMINATION OF DISSOLVED ORGANIC CARBON AND DISSOLVED INORGANIC CARBON
The determination of DOC and DIC is performed using the same procedure
that was used during ELS-I. For a discussion of the method, see Hi 11 man
et al. (1986).
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3.7 DETERMINATION OF TOTAL DISSOLVED FLUORIDE
The determination of total dissolved fluoride is performed using the same
procedure that was used during ELS-I. For a discussion of the method, see
Hill man et al. (1986).
3.8 DETERMINATION OF TOTAL PHOSPHORUS
The determination of total phosphorus is performed using the same procedure
that was used during ELS-I. For a discussion of the method, see Hillman
et al. (1986).
3.9 DETERMINATION OF DISSOLVED SILICA
The determination of dissolved silica is performed using the same procedure
that was used during ELS-I. For a discussion of the method, see Hillman
et al. (1986).
3.10 DETERMINATION OF SPECIFIC CONDUCTANCE
The determination of specific conductance is a slight modification of the
one used during ELS-I. The modified procedure requires the use of a
temperature-controlled water bath to equilibrate samples to 25 °C.
3.10.1 Scope and Application
This method is applicable to natural surface waters of low ionic strength.
The majority of lakes sampled for the NSWS have a specific conductance
in the range 10 to 100 uS/cm.
3.10.2 Summary of Method
The specific conductance in samples is measured using a conductance
meter and conductivity cell. The meter and cell are calibrated using
potassium chloride standards of known specific conductance (U.S. EPA,
1983).
Standards and samples are analyzed at 25 °C.
3.10.3 Interferences
Temperature variations represent the major source of potential error in
specific conductance determinations. To minimize this error, calibration
standards and samples must be measured at the same temperature in a
temperature-controlled water bath.
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Natural surface waters contain substances (humic and fulvic acids,
suspended solids, etc.) which may build up on the conductivity cell.
Such a buildup interferes with the operation of the cell and must be
removed periodically, following the cell manufacturer's recommendations.
3.10.4 Safety
The calibration standards and sample types pose no hazard to the analyst.
3.10.5 Apparatus and Equipment
o Specific Conductance Metei—Digital meter with the following minimum
specifications:
Range: 0.1 to 1,000 uS/cm
Readability: 0.1 uS/cm
Maximum Error: 1% of reading
Maximum Imprecision: 1% of reading
0 Conductivity Cell--High-quality glass cell with a cell constant of
1.0 or 0.1. Cells containing platinized electrodes are recommended.
o Constant-Temperature Water Bath—Controlled to a temperature of
25.0 °C ± 0.1 °C.
° Thermometei—NBS-traceable thermometer with a range of 0 to 40 °C
and divisions of 0.1 °C.
3.10.6 Reageants and Consumable Materials
• Potassium Chloride Stock Calibration Solution (0.01000M KCD —
Dissolve 0.7456 g potassium chloride (KC1, ultrapure, freshly dried
for 2 hours at 105 °C and stored in a desiccator) in water and dilute
to 1.000 L. Store in a tightly sealed LPE container.
» Potassium Chloride Calibration Solution (0.001000M KCl)--Dilute
10.00 ml KC1 stock calibration solution to 100.00 ml with water.
This solution has a theoretical specific conductance of 147.0 uS/cm
at 25 °C.
• Potassium Chloride QC Solution (0.000500M KCD— Dilute 5.00 mL 0.0100M
KC1 solution (independent of the KC1 stock calibration solution) to
100.00 ml with water. This solution has a theoretical specific
conductance of 73.9 uS/cm at 25 °C.
-------
Section 3.0
Revision 4
Date: 9/87
Page 54 of 57
° Watei—Water must meet the specifications for Type I reagent water
given in ASTM 0 1193 (ASTM, 1984).
3.10.7 Sample Collection, Preservation, and Storage
The samples are collected in the field and shipped to the lab in LPE
bottles without treatment. Store samples at 4 °C when not in use.
3.10.8 Calibration and Standardization
Step 1—Measure and record the specific conductance of the KCl
calibration solution as described in Section 3.9.10.
Step 2--Ca1culate the cell constant, Kc, using the following equation:
147.0 uS/cm
KC =
where
KClm
KClm = measured specific conductance for the KCl calibration
solution.
3.10.9 Quality Control
The required QC procedures are described in Section 3.1.3.
3.10.10 Procedure
Follow manufacturer's instructions for the operation of the meter and
cell.
Step I—Place the calibration standards, QC samples, and samples in
the constant-temperature water bath (25.0 °C ± 0.1 °C) to allow the
samples and standards to equilibrate to 25.0 °C.
Step 2—Rinse the cell thoroughly with water.
Step 3—Rinse the cell with a portion of the sample to be measured.
Immerse the electrode in a fresh portion of sample and measure its
conductance.
Step 4—Rinse the cell thoroughly with water after use. Store cell in
water.
Step 5—If the readings become erratic, the cell may be dirty or may
need replatinizing. Consult the manufacturer's operating manual for
guidance.
-------
Section 3.0
Revision 4
Date: 9/87
Page 55 of 57
3.10.11 Calculations
Calculate the specific conductance (Sc) for each sample using the
following equation:
Sc = (Kc) (Sm)
where
Kc = cell constant
Sm = measured conductance
Report the results as specific conductance, uS/cm at 25 °C.
3.10.12 Precision and Accuracy
Forty-one analysts in seventeen laboratories analyzed six synthetic
samples containing increments of inorganic salts, with the following
results (U.S. EPA, 1983):
Increment, as Precision, as
Specific Conductance Standard Deviations Accuracy
(US/cm)
100
106
808
848
1,640
1,710
In a single laboratory (EMSL-Cincinnati) using surface-water samples
with an average conductance of 536 uS/cm at 25 °C, the standard devia-
tion was 6 uS/cm (U.S. EPA, 1983).
3.11 DETERMINATION OF METALS (Al, Ca, Fe, K, Mg, Mn, Ma) BY ATOMIC ABSORPTION
SPECTROSCOPY
The determination of metals is performed using the same procedure that
was used during ELS-I. For a discussion of the method, see Hillman et al
(1986).
3.12 DETERMINATION OF DISSOLVED METALS (Ca, Fe, Mg, and Mn) BY INDUCTIVELY
COUPLED PLASMA EMISSION SPECTROSCOPY
Determination of dissolved metals by ICPES is performed using the same
procedure that was used during ELS-I. For a discussion of the method,
see Hillman et al. (1986).
(US/cm)
7.55
8.14
66.1
79.6
106
119
Bias (%)
-2.02
-0.76
-3.63
-4.54
-5.36
-5.08
Bias (uS/cm)
-2.0
-0.8
-29.3
-38.5
-87.9
-86.9
-------
Section 3.0
Revision 4
Date: 9/87
Page 56 of 57
3.13 References
APHA (American Public Health Association), American Water Works
Association, and Water Pollution Control Federation, 1985. Standard
Methods for the Examination of Water and Wastewater, 16th Ed. APHA,
Washington, D.C.
ASTM (American Society for Testing and Materials), 1984. Annual Book of
ASTM Standards, Vol. 11.01, Standard Specification for Reagent Water,
D 1193-77 (reapproved 1983). ASTM, Philadelphia, Pennsylvania.
Baker, K. S., R. C. Smith, and J. R. Nelson, 1983. Chlorophyll
determinations with filter fluorometer: Lamp/filter combinations
can cause error. Limnol. Oceanogr., v. 28, n. 5, pp. 1037-1040.
Butler, J. N., 1982. Carbon Dioxide Equilibria and Their Applications.
Addison-Wesley Publications, Reading, Massachusetts.
Gran, G., 1952. Determination of the Equivalence Point in Potentio-
metric Titrations, Part II, Analyst, v. 77, pp. 661-671.
Hillman, D. C., J. F. Potter, and S. J. Simon, 1986. National Surface
Water Survey, Eastern Lake Survey (Phase I -- Synoptic Chemistry)
Analytical Methods Manual. EPA 600/4-86/009. U.S. Environmental
Protection Agency, Las Vegas, Nevada.
Holm-Hansen, 0. and B. Riemann, 1978. Chlorophyll a_ determination:
Improvements in Methodology. Oikos, v. 30, pp. 438-477.
Kramer, J. R., 1982. Alkalinity and Acidity. In: R. A. Minear, and
L. H. Keith (eds.), Water Analysis. Volume 1: Inorganic Species,
Part 1. Academic Press, Orlando, Florida.
Kramer, J. R., 1984. Modified Gran Analysis for Acid and Base Titra-
tions. Environmental Geochemistry Report No. 1984-2. McMaster
University, Hamilton, Ontario, Canada.
Loftus, M. E. and J. H. Carpenter, 1971. A fluorometric method for
determining chlorophylls a, b and c. J. Mar. Res., v. 29, pp.
319-338. ~ ~
McQuaker, N. R., P. D. Kluckner, and D. K. Sandberg, 1983. Chemical
Analysis of Acid Precipitation: pH and Acidity Determinations.
Environ. Sci. Techno!., v. 17 n. 7, pp. 431-435.
Muir, G. D., 1980. Hazards in the Chemical Laboratory. The Chemical
Society: London, England.
-------
Section 3.0
Revision 4
Date: 9/87
Page 57 of 57
MBS (National Bureau of Standards), 1982. Simulated Precipitation
Reference Materials, IV. NBSIR 82-2581. U.S. Department of
Commerce, NBS, Washington, O.C.
National Institute of Occupational Safety and Health/Occupational
Safety and Health Administration, 1977. NIOSH/OSHA Pocket Guide
to Chemical Hazards. U.S. Government Printing Office, Washington,
O.C.
National Institute of Occupational Safety and Health, 1977. NIOSH
Manual of Analytical Methods, 2nd Ed. (4 volumes). U.S.
Department of Health, Education, and Welfare (NIOSH) Publication
No. 77-157A.
Peden, M. E., 1981. Sampling, Analytical, and Quality Assurance Proto-
cols for the National Atmospheric Deposition Program. Paper pre-
sented at October 1981 ASTM D-22 Symposium and Workshop on Sampling
and Analysis of Rain. ASTM, Philadelphia, Pennsylvania.
Rebeiz, C. A., M. B. Bazzaz, and F. Belanger, 1978. In Chromatography
Review, v. 4, n. 2, Spectra Physics.
Shelske, C. L., 1984. In Situ and Natural Phytoplankton Assemblage
Bioassays, pp. 15-47. _J_n_ Algae as Ecological Indicators.
Academic Press, London, England.
Stainton, M. P., M. J. Capel, and F. A. J. Armstrong, 1977. The
Chemical Analysis of Fresh Water, 2nd Ed. Fish. Mar. Serv. Spec.
Publ. 25, Canadian Freshwater Institute, Winnipeg, Manitoba,
Canada.
U.S. Environmental Protection Agency, 1983 (revised). Methods for
Chemical Analysis of Water and Wastes. EPA 600/4-79-020. U.S.
EPA, Cincinnati, Ohio.
Weast, R. C. (ed.), 1972. CRC Handbook of Chemistry and Physics, 53rd
Ed. CRC Press, Cleveland, Ohio.
-------
Appendix A
Revision 4
Date: 9/87
Page 1 of 8
APPENDIX A
PROCESSING LABORATORY EQUIPMENT LIST
1. Mobile Processing Laboratory Facilities
a. Electrical and water inputs
D. Water outlet
c. Source of water capable of meeting ASTM Type I specifications (such as
Barnstead NANOpure/ROpure 40 or Millipore Milli-RO/Super-Q System)
d. Heating/cooling system
e. Freezer
f. Laminar flow hood capable of delivering class 100 air
g. Solvent storage cabinet
n. Standard laboratory countertops and sink
i. Analytical balance (±0.0001 g) and plastic weighing boats
j. Vacuum pump
2. Centrifuge (capable ot holding four 50-mL tubes) - 1
3. Clean Nalgene Amber Wide-Mouth Bottles
a. 500 mL (Nalgene No. 2106-0016) - 30/day
(continued)
-------
Appendix A
Revision 4
Date: 9/87
Page 2 OT 8
PROCESSING LABORATORY EQUIPMENT LIST (Continued)
b. 250 mL (Nalgene No. 2106-0008)
c. 125 mL (Nalgene No. 2106-0004)
- 60/day
- 90/day
4. Total Extractable Aluminum Supplies
a. Clean 50-mL graduated centrifuge tubes
with sealing caps (Fisher No. 05-538-55A)
b. Clean 10-mL centrifuge tubes (Nalgene 3119-0010)
c. Clean sealing caps for 10-mL centrifuge tubes
(Nalgene 3131-0013)
d. HPLC-grade methyl isobutyl ketone (MIBK)
e. Sodium acetate (Alfa Ultrapure)
f. 8-hydroxyquinoline (99+% purity)
g. MH4OH (30% - Saker Instra-Analyzed grade)
h. Clean 1-L, 500-mL, and 100-mL volumetric flasks
i. Glacial acetic acid (Baker Instra-Analyzed grade)
j. Hydrochloric acid (12 M-Baker Instra-Analyzed
grade)
k. Phenol-red indicator solution (0.04X w/v -
American Scientific Products 5720)
1. 2.00-mL Repipet dispenser
m. 3.00-mL Repipet dispenser top for 1-gallon bottle
n. 5.00-mL Repipet dispenser
- 30/day
- 30/day
- 30/day
- 180 mL/day
- 80 g/month
- 30 g/month
- 750 mL/month
- 5 of each
- 100 mL/month
- 500 mL/month
- 1 L
- 2/station
- 2/station
- 2/station
(continued)
-------
PROCESSING LABORATORY EQUIPMENT LIST (Continued)
Appendix A
Revision 4
Date: 9/87
Page 3 ot 8
o. 100-mL reagent bottle with dropper
(Nalgene 2411-0060)
p. Polystyrene graduated cylinders
(25-, 100-, 250-mL sizes)
- 2/station
- 2 each/station
5. PCV-Reactive Aluminum Supplies
a. Clean 250-mL beaker
b. Clean 100-mL beaker
c. Lachat flow-injection analyzer
d. Micropipet, variable-volume, 1-5 uL (Finn)
e. Micropipet, variable-volume, 40-200 uL (Finn)
t. Micropipet, variable-volume, 200-1,000 uL (Finn)
g. Disposable micropipet tips, 1-200 uL
(Finn No. 60)
h. Disposable micropipet tips, 600-1,000 uL
(Finn No. 61)
i. Disposable micropipet tips, 1-5,000 uL
(Finn No. 62)
j. Polyethylene bottle, 1-L capacity
k. Volumetric tlask, 100-L capacity
1. Filter paper, Whatman GF/C
m. Cation-exchange resin (Amberlite IR-120,
14-50 mesn)
2
2
2
2
4/day
4/day
4/day
3
2
2 box/month
0.15 g/day
(continued)
-------
Appendix A
Revision 4
Date: 9/87
Page 4 ot 8
PROCESSING LABORATORY EQUIPMENT LIST (Continued)
n. Hydrochloric acid, concentrated (Baker Ultex grade or
equivalent)
o. Ammonium hydroxide, concentrated (Baker Instra-
Analyzed grade or equivalent)
p. Hydroxylammonium chloride
q. 1,10-phenanthroline
r. Hexamethylene tetramine
s. Stock Al calibration standard solution, 1,000 mg/L
t. Stock Al QC solution (1,000 mg/L), certified
standard from different source than the
calibration standard solution
u. Sodium chloride (ACS reagent grade)
v. Pyrocatechol violet
- 75 g/day
- 1 g/day
- 200 g/day
- 2 x 500 mL
6. Color Determination Kit (Hach Model CO-1)
7. Color Determination Kit Spare Supplies
a. Color disc (Hach No. 2092-00)
b. Color viewing tube (Hach No. 1730-00)
c. Hollow polyethylene stoppers (Hach No. 14480-74)
- 2
- 10
- 10
(continued)
-------
Appendix A
Revision 4
Date: 9/87
Page 5 of 8
PROCESSING LABORATORY EQUIPMENT LIST (Continued)
8. Filtration Apparatus and Supplies
a. Membrane filters, 0.45 urn, 47 mm diameter
(Gelman No. 60173) (package of 100)
b. Teflon or plastic forceps
c. Fisher filtrator - low form (Fisher 09-788)
d. Acrylic vacuum chambers (custom made)
e. Clean filter holder (Nalgene No. 310-4000)
f. Spare rubber stoppers (Fisher No. 09-788-2)
g. Vacuum pump with regulator (Millipore No.
XX5500000)
7 pkg/week
5
3
6
12
6
- 1
9. Disposable Gloves (talc-free)
10. Preservation Supplies
a. Repipet Jr. (0.1 mL)
b. Indicating pH paper (Whatman Type CS No. 2626-990
range 1.8 to 3.8)
c. HN03 and ^804 (Baker Ultrex grade or Seastar
Ultrapure grade)
- 2
- 6 packs/week
- 50 mL/week
(continued)
-------
Appendix A
Revision 4
Date: 9/87
Page 6 or 8
PROCESSING LABORATORY EQUIPMENT LIST (Continued]
11. Frozen Freeze-Gel Packs - daily use (reuseable)
- shipping
12. Styroroam-Lined Shipping Containers
- 25/day
- 30 to 40/sample
batch
- 4/day
13. Field Data Forms, Shipping Forms, Batch Forms, etc.
14. Color Blindness Test Kit
- 1
15. DIC Determination Supplies
a. Dohrman DC-80 carbon analyzer
b. 50-mL polypropylene syringes - station use
- field use
- 1
c. Mininert syringe valves
d.
e.
f.
- station use
- field use
Zero-grade nitrogen gas
Anhydrous Na2C03 (ACS Primary Standard Grade)
Syringe membrane filters (Gelman Acrodisc
4218, 0.45 urn)
Spare carbon analyzer parts (nuts, ferrules,
tubing, etc.)
50
I/sample
20
70
1 cylinder/
month
500 g
- I/sample
(continued)
-------
Appendix A
Revision 4
Date: 9/87
Page 7 of 8
PROCESSING LABORATORY EQUIPMENT LIST (Continued)
16. Processing LaDoratory pH Supplies
a. pH meter (Orion Model 611)
b. Orion Ross epoxy body combination pH electrode
c. Filling solution for Ross combination pH
electrode (pack of 6 bottles)
d. pH sample chamber
e. Certified 0.100 N H2S04
f. Ringstand (to hold pH apparatus) and clamps
g. NBS-traceable pH buffers (pH 4 and 7)
h. 50-mL disposable beakers
2
6
2
2
2 L
2
2 L of each/
month
200
17. Turbidimeter (Monitek Model 21)
- 1
18. Turbidimeter Supplies
a. 5-, 10-, 20-, 50-, 100-, 200-NTL) standards
b. Cuvettes
1 L of each
10
19. Class 100 Air Filtration Filters
20. Spare Water Treatment Cartridges
- 6
- 6
(continued)
-------
Appendix A
Revision 4
Date: 9/87
Page 8 of 8
PROCESSING LABORATORY EQUIPMENT LIST (Continued!
21. Coolers
- 4
22. Clean 20-L Cubitainers with Spigots - 5
23. Digital Micropipets (5-40 uL, 40-200 uL, 200-1,000 \iL,
1,000-5,000 ML)
24. Micropipet Metal-Free Pipet Tips (in tour sizes
corresponding to micropipet sizes in item 27)
25. Snowpack/Bulk Precipitation Supplies
Racks—to hold buckets during sample-melting process
Sample buckets (spare)
Syringes (60 ml, plastic)
Syringe valves (Luer-Lok)
Scale, capable of accurate measurement within 0.005 pound
- 1 of each
2 cases (1,000
tips/case)
of each size
-------
Appendix 3
Revision 4
Date: 9/87
Page 1 of 19
APPENDIX 3
MSVJS BLANK DATA FORMS
The NSWS forms shown in this appendix are facsimiles of the forms used in the
laboratory.
-------
NATIONAL SURFACE WATER SURVEY
FORM 11
SUMMARY OF SAMPLE RESULTS
Page 1 of 2
LAB HAUL BAICII 11)
SAMPLE
ID:
01
02
03
04
OS
06
07
OS
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
LAB MANAGER'S SIGNATURE
ALIQUOT ID
1
Ca
mg/L
Mg
mg/L
K
mg/L
Na
mg/L
Mn
nig/L
Fe
mg/L
2
Total
Extr. Al
mg/L
3
cr
mg/L
so'-
mg/l.
NO-,"
mg/L
SiO-,
mg/L
ISE
Total F"
mg/l
-o a A; u»
Qj QJ fD "^D
cQ r+ < "O
n> n> -•• n>
(Ni -•• Q.
o -••
O vO 3 X
co r- uj
NOTE: Approved data qualifiers and instructions for their use are listed in Table 3-10.
NSWS Form 11
-------
NATIONAL SURFACE WATER SURVEY
FORM 11
Page 2 of 2
LAB NAME
BATCH ID
SUMMARY OF SAMPLE LIMITS
LAB MANAGER'S SIGNATURE
SAMPLE
ID:
01
02
03
04 "
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
?9'
30
31
32
33
34
35
36
37
38
39
40
ALIQUOT ID
4
OOC
mg/L
NH4*
mg/L
5
Measured
Eq.
PH
ANC
Init. pH
BNC
Init. pH
CO,
BNC
ueq/L
ANC
ueq/L
COND.
uS/cm
Eq.
D1C
mg/L
Init.
DIC
mg/L
6
Total
P
mg/L
7
Total
Al
ing/L
NOTE: Approved data qualifiers and instructions for their use are listed in Table 3-10.
NSWS Form 11 (Continued)
ru OJ ft> T3
LQ rt < d
(D CD -•• CD
O -••
O 'O 3 X
-f> "~^
OO -p>. LO
l— • -~J
10
-------
Appendix 3
Revision 4
Oate: 9/87
Pago 4 of 19
NATIONAL SURFACE WATER SURVEY
Form 13
Page 1 of 1
ANC AND BNC RESULTS
Lab Name
Lab Manager's Signature
RESULTS
[ANC] =
IC07-BNCJ =
ueq/L
ueq/L
Batch ID Sample ID
Analyst
Initial Sample Volume =
Blank ANC =
mL
ueq/L
DATA
CA
eq/L DATE STANDARDIZED
eq/L DATE STANDARDIZED
ACID TITRATION
BASE TITRATION
VOLUME HC1
(mL)
0.00
0.00 (with KC1)
|
1
i
MEASURED
pH'
1
CALCULATED
pH
1
VOLUME NaOH
(mL)
0.00
0.00 (with KC1)
MEASURED
PH'
i
CALCULATED
PH
i
NSWS Form 13
-------
Append!x 3
Revision 3
Date: 9/87
Page 5 of 19
NATIONAL SURFACE WATER SURVEY
Form 14a
Page 1 of 1
LAB NAME
QC DATA FOR ANC AND 8NC ANALYSES
BATCH ID
LAB MANAGER'S SIGNATURE
SAMPLE
ID
01
u2
03
ANC
yeq/L
CO,-BNC
yeq/L
04
05
06
07
ua
09
10
11
12
13
14
15
16
17
Id
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
4(1
CALCULATED ANC
RESULT
i
DIFFERENCE
JXC
1
1
Form not required in data package Out recommended tor internal QC requirements.
^Difference =• Calculated ANC-Heasured AIIC
QIC (in unoles/L)-([ANC] » CCO?_-BNC]1
JX
100
DIG
MSWS Form 14*
-------
I All IIAME
IAB
SIGNATURE:
NATIONAL SURFACE WATER SURVEY
Form 15*
CONDUCT IVIIV
BATCH 10
Page 1 of 1
Sample
ID
01
02
03
04
05
06
07
' Ofl"
"09
10
11
12
13
14
15
16
17
""18 ~
" 19
20
21
22
23
24
2$
26
27
28
29
30
31 •
32
33
34
35
36
37
38
39
40
SPECIFIC CONDUCTANCE
(uS/cra)
Calculated
Measured
ICO"
Conductance Factors of Ions
[(pS/cm at 25'C) per mg/L]
CALCULATED CONDUCTANCE FOR EACH ION p S/cm
HCOj
0.715
Ca'?
2.60
co3-'
2.82
cr
2.14
•Form not required in data package but recommended for internal Q
H,*
3.82
C requ
«o3-
1.15
K*
1.84
Ndl
2.13
so,?-
1.54
• H4*
4.13
Hf
(per
nole/L)
oir
(per
mole/I.)
rements
Calculated Cond.-Measured Cond.
•i Conductance Difference -
x 100
Measured Conductance
NSWS Form 15
co cu co a
i£l r+ < T3
(T> rD —•• fD
• • Lrt 3
cn -•• o
O -••
O -D 3 X
-ti •
OO J^ t-O
-------
Appendix 3
Revision 4
Date: 9/87
Paae 7 of 19
LAB NAME
NATIONAL SURFACE WATER SURVEY
Form 16*
ANION-CATION BALANCE CALCULATION
BATCH ID
Page 1 of 1
LAB MANAGER'S SIGNATURE
Ions (ueq/L)
Sample)
ID
01
02
03
04
5 Ion
Difference**
Ca2+
!
cr
Hg2+
N03"
K*
^
V
f
<
i
1 ' ! i
05 • i i j
06 i i i 1
oT
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
23
«
30
31
32
33
34
35
36
37 '
38
39
40
Factor to Convert
mg/L to ueq/L
49.9
128.2
i
182.3
1
16.1
25.6
l
43.5
i
i
ANC
Hf***
i
i
1
20.8
52.6
1
55.4
ANC * £ Anions - Z Cations (exceot H*)
"1 Ion Difference = ——•
I Anions * t Cations * ANC * 2[H+]
•**[H+] * (10-PH) x 106 ueq/L
x 100
NSWS Form 16
-------
Appenaix 3
.Revision 4
Date: 9/37
Page 6 of 1
NATIONAL SURFACE VlATER SURVEY
Form 17 ?aae 1 of 1
1C RESOLUTION TEST
LAB ilAME
3ATCH ID
LAB MANAGER'S SIGNATURE
1C Resolution Test
iC Make and Model :
Date:
Concentration: S042" Mg/mL, N03~ ug/mL
Column Back Pressure (at max. of stroke): : psi
Flow Rate: mL/min
Column Model: Date of Purchase:
Column Manufacturer:
Column Serial No:
Is precolumn in system Yes No
(a) cm (b) cm
Percentage Resolution: 100 x (1-a/b)
The resolution must be greater than 60%
Test Chromatooram:
NSUS Form 17
-------
Appendix 3
Revision 4
Date: 9/87
Page 9 of 19
,'IATIONAL SURFACE WATER SURVEY
Form 13
Page 1 of 1
DETECTION LIMITS
LAB NAME
BATCH ID
LAB MANAGER'S SIGNATURE
Parameter
Ca
Mg
K
Na
Mn
Fe
A1, total
extractable
ci-
v
N03~
SI 02
F-. total
NH4+
DOC
Specific
Conductance
DIG
P. total
Al , total
Units
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
uS/cm
mg/L
mg/L
mo/L
Instrumental
Contract Required Detection Date Determined
Detection Limit Limit (DO MMM YY)
0.01
0.01
0.01
0.01
0.01
0.01
0.005
0.01
0.05
0.005
0.05
0.005
0.01
0.1
*•
0.05
0.002
0.005
/
•Report the X, which must not exceed 0.9 uS/cm, of six nonconsecutive blanks.
Mote: Report with four significant figures or down to IDL.
NSWS Form 18
-------
Aopendix 3
Revision 4
Date: 9/87
Paae 10 of 19
NATIONAL SURFACE HATER SURVEY
FORM 19
Page 1 of 2
LAB NAME
BATCH ID
SAMPLE HOLDING TIME SUMMARY
LAB MANAGER'S SIGNATURE
Holding Time
Plus
'Date Sampled
•Peoort tnese dates as Julian oates (i.e.. Marc
analyzed.
'1SWS Form 19
-------
Aopendix 3
Revision 4
Date: 9/87
D:iqe 11 of 19
NATIONAL SURFACE WATER SURVEY
FORM 19
Page 2 of 2
LAB NAME
BATCH ID
SAMPLE HOLDING TIME SUMMARY
LAB MANAGER'S SIGNATURE
DATE* PROCESSED
DATE* RECEIVED
Parameter
Holding
Time
Holding Time
Plus
Date Samoled
DOC
14
NHd*
28
Eo. pH
7
ANC
14
BNC
14
Specific
Conductance
14
Eq. DIC
14
Init. DIC
14
Total P
28
Total Al
28
Sanole ID: Date* Analyzed'*
Jl , ,
02 ' . ! . i
03
04
1)3
06
~07
08
09
10
il
12
13
14
15
~T?
! ' 1 •
i 1
i
1
i I 1
17
13 i 1
19
~20 ' 1
21 1
22
i
23 ' ;
24
25
26
27
28
29
30
~Tl 1
32
33
34
35
36
i
37 •
~S6 i
39 i
—
1
|
i 1
1
40 iii
i
!
l i
I
|
i
i
i
1 1
*?eport tnese dates as oulian dates (i.e., Marcn 26, 1934 = 40861).
"If parameter was reanalyzed due to QA problems, report the last date analyzed.
NSWS Form 19 (Continued)
-------
NATIONAL SURFACE WATER SURVEY
FORM 20
Page 1 of 2
LAB NAME
BLANKS AND QCCS
BATCH ID
LAB MANAGER'S SIGNATURE
Parameter
Calibration
Blank
Reagent Blank
OL (Theoretical
QCCSJMeasured
Low QCCS
True Value
Low QCCS Upper
Control Limit
Low QCCS Lower
Control Limit
Initial
Continuing
Continuing
Continuing
Continuing
Continuing
Final
High QCCS
True Value
High QCCS^Upper
Control Limit
High QCCS Lower
Control Limit
Initial
Continuing
Continuing
Continuing
Continuing
Continuing
Final
ALIQUOT ID
1
Ca
mg/L
N
Note: Approved data qua
Hg
mg/L
N
K
mg/L
N
Na
mg/L
N
Mn
mg/L
N
Fe
mg/L
N
2
Extr.
Al
mg/L
N
3
cr
mg/L
N
so/'
mg/L
N
HO,"
mg/L
N
Si 0,
mg/L
ISE
Total r
mg/L
N
N
N
ifiers and instructions for their use are listed in Table 3-10.
XI l_J >J 'J-
cu fu m o
iQ r-»- < "O
o> n> -•• n>
n
(NO
o
+, co
NSWS Form 20
-------
NATIONAL SURFACE WATER SURVEY
FORM 20
Page 2 of 2
LAB NAME
BLANKS AND QCCS
HATCH IU
LAB MANAGER'S SIGNATURE
Parameter
Calibration
Blank
Reagent Blank
DL (theoretical
QCCSJmeasured
Low QCCS
True Value
Low QCCS Upper
Control Limit
Low QCCS Lower
Control Limit
Initial
Continuing^
Continuing
Continuing
Continuing
Continuing
Final
High QCCS
True Value
High QCCS Upper
Control Limit
High QCCS Lower
Control Limit
Initial
"ont inuing
Continuing
Continuing
Continuing
Continuing
Final
4
DOC
mg/L
N
NH,+
my/L
N
ALIQUOT ID
Measured
Eq
PH
N
N
N
N
ANC
pH
N
N
N
N
BNC
PH
N
N
N
N
5
Spec.
Cond.
gS/cm
N
N
N
Eq.
OIC
mg/L
N
Init.
DIC
nicj/L
N
6
Total
P
my/L
N
7
Total
Al
mg/L
Note: Approved data qualifiers and instructions for their use are listed in
Table 3-10.
u> re o
(-»• < -a
a> ->• ro
-*• CL
O -••
3 X
NSWS Form 20 (Continued)
o -^
-h CO
--J
-------
LAb NAME
NATIONAL SURFACE WATER SURVEY
Form 22
BATCH ID
DUPLICATES
LAB MANAGER'S SIGNATURE
1 ol 2
Parameter
Dupl icate
Sample ID
Sample Result
Dupl icate
Result
% RSD
Second Dupl icate
Sample 10
Sample Result
Dupl icate
Result
% RSD
\
Third Dupl icate
Sample 10
Sample Result
Oupl icate
Result
% RSD
ALIQUOT ID
1
Ca
mg/L
Note: Approved data qua
Hg
mg/L
K
mg/L
Na
mg/L
Mn
mg/L
Fe
mg/L
2
Total
Extr.Al
mg/L
3
Cl-
ing /L
so42-
mg/L
no-j-
mg/L
SiOo
mg/L
ISE
lolal !•'-
mg/L
ifiers and instructions for their use are listed in Table 3-10.
NSWS Form 22
V O ,0 j.-
CU £U ft> O
03 c-l < 13
fD fl> —•• IT)
• • Ul 3
t— -*• Q
.£» O -•
-O 3 X
O ~^
-t, co -p. '_o
-------
NATIONAL SURFACE WATER SURVEY
Form 22
Page 2 of 2
LAB NAME
BATCH ID
OUPL1CAILS
LAB MANAGER'S SIGNATURE
Note: Approved data qualifiers and instructions for their use are listed in Table 3-10.
*Report absolute difference rather than %RSD for pH determinations.
Parameter
Dupl icate
Sample ID
Sample Result
Dupl icate
Result
% RSD*
Second
Dupl icate
Sample ID
Sample Result
Dupl icate
Result
% RSD*
Third Dupl icate
Sample ID
Sample Result
Dupl icate
Result
% RSD*
ALIQUOT ID
4
DOC
mg/L
NH/
mg/L
Measured
Eq.
pH
ANC
Initial
PH
BNC
Initial
PH
5
C02-
BNC
ueq/L
ANC
ueq/L
Spec.
Cond.
uS/cm
tq.
DIC
mg/L
Init.
DIC
mg/L
6
Total
P
ITHJ/L
7
Total
Al
mg /L
-U U 70 •>-
& 01 n> o
IO <-+ < ~O
fO ft) -•• CD
>—
cn
o
-•• Q.
O — <•
3 x
oo
NSWS Form 22 (Continued)
-------
Aooendix 3
Revision 4
Date: 9/87
?aae 16 of 19
BATCH ID:
NATIONAL SURFACE WATER SURVEY
FORM 31
SUMMARY OF ANALYTICAL RESULTS - PHYTOPIGMENTS
LAB NAME:
LAB MANAGER'S SIGNATURE:
Ul
u^
UJ
04
Ub
Ub
oy
08
uy
lo
11
12
13
14
Ib
16
I/
18
SAMPLE
ID
EXTRACT
VOLUME
(ml)
T9l
20
i\
ii
2J
24
25
2b
21
2TT """
29
JO
31
J2
JJ
J4
3b
Jb
CHLa (ug/L)
FLUOROMETRIC
UNCORRECTED
CHLa (ug/L)
HPLC
]
I
I
1 i I
37
381 t
39| 1
40
PHEa (ug/L)
HPLC
OTHERS,
COMMENTS
NSWS Form 31
-------
BATCH ID:
NATIONAL SURFACE WATER SURVEY
FORM 32
QC RESULTS - PHYTOPIGMENTS
FLUOROMETRY
LAB MANAGER'S SIGNATURE:
DATE:
Appendix 3
Revision 4
Date: 9/87
Page 17 of 19
ITEM
RESULT*
COMMENTS
METHOD DETECTION LIMIT
_Mg/L CHLa_*
BLANK
jig/L CHLa*
RESPONSE FACTORS
XI
X3
X10
X30
CALIBRATION CHECK pg/L
Standard cone. CHLa*
jig/L CHLa*
DUPLICATES
SAMPLE ID
a)
b)
MEAN
Mg/L CHLa*
~ CHLa*
CHLa
Calculate as for a 200-mL sample
NSWS Form 32
-------
Appendix 3
Revision 4
Date: 9/87
Page 18 of 19
NATIONAL SURFACE WATER SURVEY
FORM 33
QC RESULTS - PHYTOPIGMENTS
HPLC
ITEM
RESULT*
COMMENTS
METHOD DETECTION LIMIT
Mg/L CHLa_
jjg/L PHEa_
BLANK
Mg/L CHLa_
jjg/L PHEa_
RESPONSE FUNCTIONS
CHLa;
PHEa:
CALIBRATION CHECK
Standard cone. M9/L
Standard cone. Mg/L
Standard cone. Mg/L
CHLa_
Mg/L Standard cone. Mg/L
~Mg/L Standard cone. Mg/L
~Mg/L Standard cone. Mg/L
PHEa
Mg/L
"Mg/L
"Mg/L
Standard
Standard
Standard
DUPLICAT
cone. Mg/L
cone. Mg/L
cone. Mg/L
ES
a)
b)
MEAN:
a)
b)
MEAN:
Mg/L
Mg/L
Mg/L
SAMPLE
Mg/L CHLa*
Mg/L CHLa*
SAMPLE
Mg/L CHLa*
Mg/L CHLa*
Standard cone. Mg/L
Standard cone. Mg/L
Standard cone. Mg/L
ID
Mg/L PHEa*
Mg/L PHEa*
ID
Mg/L PHEa*
Mg/L PHEa*
Mg/L
Mg/L
COMMENTS
^Calculate as for a 200-mL sample
NSWS Form 33
-------
Appendix 3
Revision 4
Date: 9/87
?age 19 of 19
NATIONAL SURFACE WATER SURVEY
FORM 34
QC RESULTS - PHYTOPIGMENTS
TIME LINE
RUN
NUMBER
01
SAMPLE
(STANDARD) ID
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
EXTRACTION
TIME
FLUOR.
ANALYSIS
TIME
i
|
i 36 !
1 37 !
j 38 j
39 i
40
HPLC
ANALYSIS
TIME
MSWS Form 34
-------
Appendix C
Revision 4
Date: 9/87
Page 1 of 29
APPENDIX C
EXAMPLES OF CALCULATIONS REQUIRED FOR
ANC AND BNC DETERMINATIONS
1.0 HC1 STANDARDIZATION (SECTION 3.2.8.1)
1.00 mL of 0.01038N Na2CC>3, 4.00 mL 1.0 M KC1, plus 36.00 mL C02-free
deionized water is titrated with HC1 titrant. The titration data are given
below.
mL HC1
added
0.00
0.100
0.200
0.300
0.400
0.500
0.600
0.700
pH
10.23
9.83
9.70
9.54
9.28
8.65
7.20
6.71
mL HC1
added
0.800
0.900
1.000
1.100
1.200
1.300
1.400
1.500
pH
6.37
6.03
5.59
4.91
4.48
4.26
4.11
4.00
mL HC1
added
1.700
1.900
2.100
2.300
2.500
PH
3.84
3.72
3.63
3.56
3.49
1S calculated for the data sets (V, pH) that are within the pH range
4 to 7 using the equation
Flb
(vs + v)
r / j.
Vr / rui"*"ii/ -L. 9 v \i
,\> 1 Ln JISi * t l\ i (So
S | 1 1 ^
(vs.
i- V)
\[H+]2 + [H+]K
+ i/ l/
, . i\ i NO
where
Vs = initial sample volume (41.00 mL)
V = volume of HC1 added
C = 1.266 x 10~4 = (N NaoCOo)/(2 x 41)
+] = 10-PH 2 3
K, = 7.079 x 10"7
K2 = 1.202 x 10"10
Kw = 1.660 x 10"14
-------
The (V, F ]_[.}) values are tabulated below.
Appendix C
Revision 4
Date: 9/87
Page 2 of 29
V
0.700
0.800
0.900
1.000
Flb (x 10"3)
4.07
3.22
2.20
1.01
V
1.100
1.200
1.300
1.400
1.500
Flb (x 10'3)
-2.36
-1.29
-2.26
-3.24
-4.21
The plot of Fib versus V is shown in Figure C-l. The data lie on a
straight line and are analyzed by linear regression to obtain the coefficients
of the line F^b = a + bV. From the regression,
r = 0.999
a = 0.01160 ± 0.00013
b = -0.01062 ± 0.00016
Then Vj. = -a/b = 1.092 ml
and
N Na2C03 x V Na2C03 (0.01038) (1.00)
NHC1 = - = - = 0.009505 eq/L
V 1.092
-------
Aopenaix C
Revision 4
Date: 9/87
?aoe 3 of 29
o
o
o
X
•*^
m
5-
4-
3-
2-
1-
0
•1 -
•2-
•3-
-4-
•5
0.4
I
0.6
Y-INTERCEPT = 0
SLOPE =-0.0106
R = 0.999
16
V
I • I • I
0.8 1 1.2
VOLUME HCI (mL)
1.4
1.6
i
1.8
Figure C-l. Plot of Flt) versus V for HCI standardization,
-------
Appendix C
Revision 4
Date: 9/87
Page 4 of 29
2.0 INITIAL NaOH STANDARDIZATION WITH KHP (SECTION 3.2.8.2)
5.00 mL of 9.793 x 10"4 N KHP, 2.00 mL 1.0 M KC1, plus 13.0 mL C02-free
deionized water are titrated with approximately 0.01N NaOH. The titration data
and appropriate Gran function values are given in the table below.
Volume NaOH
(ml) pH F3b(x 10"3)
0.000 4.59
0.050 4.78
0.100 4.97 3.90
0.150 5.14 3.39
0.200 5.31 2.86
0.250 5.48 2.34
0.300 5.66 1.82
0.350 5.87 1.29
0.400 6.14 0.79
0.450 6.66 0.26
0.500 8.99 -0.25
0.550 9.26 -0.77
0.600 9.48 -1.28
0.700 9.95 -2.29
0.900 10.23 -4.40
1.100 10.39 . '
1.300 10.51
-------
r v c
s
1 (vs + v)
/ [H+]K1 + 2[H"1']2 \
l([H+]2 + [H+]K1 + KLK2) 1
Kw "
i rn^T
i |_ll J
CH+]
Appendix C
Revision 4
Date: 9/87
Page 5 of 29
The Gran function F3b is calculated for data with pH 5-10. F3b is
calculated by
F3b -
-------
Aopenaix C
Revision 4
Date: 9/87
?aae 6 of 29
CO
O
CO
u.
3-
2-
1-
-1-
-2-
-3-
-4-
-5-1
0.1 0,3
0.7 0.9
•'igure C-2. Plot of F3b versus V for initial NaOH standardization with KHP,
-------
Appendix C
Revision 4
Date: 9/87
Page 7 of 29
3.0 NaOH-4Cl STANDARDIZATION CROSS-CHECK (SECTION 3.2.8.3)
0.500 ml of 0.00921N NaOH, 2.50 mL 1.0 M KC1, and 22.0 ml C02-free deionized
water is titrated with 0.0101N HC1 (standardized with Na2C03). The titration
data and appropriate Gran function values are given in the table below.
Volume HC1
(mL)
0.000
0.100
0.200
0.250
0.300
0.350
0.400
0.450
0.500
0.550
0.600
0.650
0.700
0.800
The Gran function Fj
calculated by
r-
Vs = initial
V = volume
K,. = 1.660 x
[H + ] = 1Q-PH
pH
10.07
9.93
9.77
9.71
9.58
9.40
9.15
8.13
4.76
4.44
4.26
4.12
4.04
3.88
is determined for data in
/ Kw
! = (V. f V) 0
1 s \CH+]
samole volume = 25.0 mL
of HC1 added
10'"
FL (x io"3)
2.46
2.15
1.60
1.06
0.59
0.057
-0.44
-0.93
-1.41
-1.95
-2.34
the pH range 4 to 10.
1+] j
is
-------
Appendix C
Revision 4
Date: 9/87
Page 8 of 29
FI versus V is plotted in Figure C-3. The data are on a straight line
with the equation F]_ = a + bV. The coefficients, determined by linear
regression, are
r = 0.999
a = 0.00453 ± 0.00005
b = -0.00990 ± 0.00010
From these values, V^ and N'^n are calculated by
Vi = -a/b = 0.4576
NNaOH x vNaOH
= - = 0.01006
Comparing this value for N'HCI with the previously determined value of
, the absolute RPD is
RPD in N values =
0.01006 - 0.0101
x 100 = 0.42
0.5 (0.01006 + 0.0101)
This RPD is acceptable because it is less than 5 percent.
-------
Acpenaix C
Revision 4
Date: 9/87
Page 9 of 29
CO
6
•igure C-3. ?1ot of FL versus V for NaOH-HCl standardization cross-check.
-------
Appendix C
Revision 4
Date: 9/87
Page 10 of 29
4.0 DAILY NaOH STANDARDIZATION WITH STANDARDIZED HC1 (SECTION 3.2.8.4)
1.000 mL of an approximately 0.01N NaOH solution, 2.50 ml 1.0 M KC1, and
21.50 mi C02~free deionized water are titrated with 0.009830N HC1. The
titration data are given below.
mL HC1
added p_H
1.200 3.78
1.400 3.62
mL HC1
added
0.00
0.200
0.400
0.600
0.650
0.700
pH
10.24
10.10
9.90
9.51
9.32
8.97
ml HC1
added
0.750
0.800
0.850
0.900
1.000
1.100
PH
5.44
4.65
4.37
4.22
4.02
3.88
FI is calculated for each data pair (V, pH) in the pH range 4 to 10 using
the equation
/ Kw \
F, = (V, + V) - [H+]
S \[H+] /
where
Vs = initial sample volume (25.00 mL)
Y = volume of HC1 added
K,, = 1.660 x 10"14
= 10~PH
-------
Appendix C
Revision 4
Date: 9/87
Page 11 of 29
The new data pairs (V, Fj) are tabulated below.
V F! (x 10~3) V Fi (x IO"3)
0.400
0.600
0.650
0.700
0.750
0.800
3.35
1.38
0.89
0.40
-0.093
-0.58
0.850
0.900
1.000
1.100
-1.10
-1.56
-2.48
-3.44
A plot of FI versus V is shown i.n Figure C-4. The data sets corresponding
to volumes from V = 0.40 to V = 1.10 lie on a straight line with the equation
F! = a + bV.
The coefficients are obtained by linear regression. The results are
r = 1.000
a = 0.00720 ± 0.00004
b = -0.009710 ± 0.00047
From these results,
Y! = -a/b = 0.741
and
NHC1 x vl (0.009830) (0.741)
NNaOH = = = 0.00728
VNaOH 1-000
-------
Appendix C
Revision 4
Date: 9/37
?age 12 of 29
3-
2-
1-
eo
O
-1-
-2-
-3-
-4 J
0.4 0.6
1.0 • 1.2
rigure C-4. Plot of Fj_ versus V for daily NaOH standardization,
-------
Appendix C
Revision 4
Date: 9/87
Page 13 of 29
5.0 ELECTRODE CALIBRATION (SECTION 3.2.8.5)
This section describes the electrode calibration procedure. The tables
below (A and B) tabulate the titration data (V and pH), the calculated pH
values (pH*), and the coefficients for the line pH = a + b pH*.
TABLE A. ACID TITRATION
YS =
50.00
mL
Volume HC1
(ml)
0
0
0
0
0
0
0
0
0
0
.000
.025
.050
.100
.150
.200
.250
.300
.350
.400
5
5
4
4
4
4
4
4
4
4
NHC1 = 0.00983
PH
.87
.25
.97
.68
.51
.38
.29
.22
.15
.10
-
5
5
4
4
4
4
4
4
4
pH*
—
.31
.01
.71
.54
.41
.31
.24
.17
.11
Volume HC1
(mL)
0
0
0
0
1
1
1
1
2
.450
.500
.600
.800
.000
.200
.500
.700
.000
PH
4
4
3
3
3
3
3
3
3
.05
.00
.92
.80
.71
.64
.55
.50
.43
4
4
3
3
•3
3
3
3
3
pH*
.06
.02
.94
.81
.72
.64
.55
.50
.43
r = 1.00 a = 0.10 ± 0.01 b = 0.971 ± 0.002
-------
Appendix C
Revision 4
Date: 9/87
Page 14 of 29
TABLE B. BASE TITRATION
Vs = 50.0 ml
NNaOH
Volume NaOH
(ml) pH
0
0
0
0
0
0
0
.000
.050
.200
.300
.400
.500
.600
====
6
8
9
9
9
9
9
.66
.67
.28
.34
.40
.66
.74
= 0.00804
pH*
—
8.
9.
9.
9.
9.
9.
-
68
29
46
58
68
76
Volume NaOH
(ml) pH
0
0
1
1
1
1
1
.820
.940
.080
.200
.300
.400
.500
9
9
9
10
10
10
10
.87
.93
.99
.04
.07
.11
.13
pH*
9
9
10
10
10
10
10
.89
.95
.01
.06
.09
.12
.15
r = 0.99 a = 0.08 ± 0.27 b = 0.99 ± 0.03
The data in Tables A and B are plotted in Figure C-5. Except for two
points in the base titration (at V = 0.3 and 0.4), the data lie on a straight
line. (The lines calculated for each titration are essentially coincident as
indicated by their coefficients.) Excluding these two points, the data are fit
to the line with the equation pH = a + b pH*. The coefficients of the line
(obtained by linear regression) are
r = 1.0000
a = -0.014 ± 0.0011
b = 0.999 ± 0.002
-------
11-1
10-
X
a
Aopendix C
Revision 4
Date: 9/87
Dage 15 of 29
PH*
rigure C-5. Plot of pH* versus pH for electrode calibration.
-------
Appendix C
Revision 4
Date: 9/87
Page 16 of 29
6.0 BLANK ANALYSIS - ANC DETERMINATION (SECTION 3.2.9.2)
This section provides an example for the determination of ANC in a blank
solution. The blank is prepared by adding 4.00 ml 0.10M NaCl to 36.00 nt
deionized water. It is titrated with 0.00983N HC1. The titration data are
given below (both measured and calculated pH* values are included).
Volume HC1
(ml)
0
0
0
0
0
0
.000
.080
.120
.200
.300
.400
5
4
4
4
4
4
PH
.84
.69
.52
.31
.14
.01
Volume HC1
pH* Fia (mL)
5.85
4.70
4.53
4.32 0.00192
4.14 0.00292
4.02 0.00386
0
0
0
1
1
1
.500
.600
.700
.000
.200
.500
3
3
3
3
3
3
PH
.91
.84
.77
.62
.55
.45
3
3
3
3
3
3
pH*
.91
.84
.77
.62
.55
.45
FI.
0.00498
0.00587
0.00691
0.00984
0.0116
0.0147
The Gran function Fla (Fla = (Vs + V) [H+])
where
Vs = initial sample volume = 40.00 mL
V = volume of HC1 added
H+ = 10~PH
is calculated for pH* value less than 4.5 and the values are included in the
table.
versus V is plotted in Figure C-6. The data are linear and fit the
line Fia = a + bV using linear regression. The resulting coefficients are
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i.ooendix C
Revision 4
Oate: 9/87
?aae 17 of 29
14-
12-
10-
co
i
6-1
4-
2-
0.2
i
0.4
0.6
0.8
V
1.0
l
1.2
1.4
:iqure C-6. Plot of Fla versus V for ANC determination of blank
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Appendix C
Revision 4
Date: 9/87
Page 18 of 29
r = 0.9999
a = (-0.3 ± 5.0) x 10~5
b = 0.009777 ± 0.000061
From this,
Vj = -a/b = 3.07 x 10"4 ml
and
V1CHC1 0 eP
ANC = = 7.6 x ID'8 — = 0.08
Vsa L
This value for ANC is acceptable.
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Appendix C
Revision 4
Date: 9/87
Page 19 of 29
7.0 SAMPLE ANALYSIS
7.1 TITRATION DATA (SECTION 3.2.10)
A natural lake sample was titrated as described in Section 3.2.10. The
titration data are given below. Also included are values for the
calculated pH (pH*).
Acid Titration
Vsa = 36.00 nt Vsalt = 4.00 mL
Ca = 0.00983 eq/L
Va pH pH* Va pH pH*
0.000
0.040
0.080
0.120
0.140
0.160
0.260
0.280
0.380
5.10
4.89
4.71
4.56
4.50
4.44
4.24
4.21
4.08
5.11
4.90
4.72
4.57
4.51
4.44
4.24
4.21
4.08
0.460
0.550 '
0.650
0.750
0.900
1.100
1.400
1.700
3.99
3.91
3.84
3.77
3.69
3.61
3.50
3.42
3.99
3.91
3.84
3.77
3.69
3.61
3.50
3.42
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Appendix C
Revision 4
Date: 9/87
Page 20 of 29
Base Titration
Vsb =
Cb = 0
Vb
0.00
0.015
0.030
0.050
0.080
0.120
0.160
0.200
0.240
0.280
0.320
0.340
0.360
0.380
0.400
36.00 ml
.00702 eq/L
PH
5.08
5.13
5.26
5.35
5.57
5.78
6.06
6.30
6.65
6.98
7.29
7.46
7.62
7.83
8.03
Vsalt = 4-°°
pH*
5.09
5.14
5.27
5.36
5.58
5.79
6.07
6.31
6.66
7.00
7.31
7.48
7.64
7.85
8.05
ml
Vb
0.425
0.470
0.500
0.540
0.560
0.600
0.660
0.700
0.780
0.900
1.000
1.100
1.405
1.700
2.200
2.500
pH
8.30
8.66
8.85
9.01
9.10
9.21
9.35
9.44
9.57
9.72
9.83
9.92
10.12
10.26
10.43
10.51
pH*
8.32
8.68
8.87
9.03
9.12
9.23
9.37
9.47
9.60
9.75
9.86
9.95
10.15
10.29
10.43
10.54
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Appendix C
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Page 21 or 29
7.2 INITIAL ESTIMATE OF Vj (SECTION 3.2.11)
The Gran function Fia is calculated for eacn data pair from the acid
titration that has a pH* less than 4. The values are given in the table
below.
va
0.460
0.550
0.650
0.750
Fla(xlO~3)*
4.14
4.99
5.88
6.92
Va
0.900
1.100
1.400
1.700
Fla(xlO-3)*
8.35
10.10
13.10
15.90
*Fla = (V, + V.) [H+] .
J. O 3 Q
versus Va is plotted in Figure C-7. A regression of Fja on Va is
performed to fit the data to the line Fja = a + bV. The resulting
coefficients are
r = 0.9999
a = -0.000241 ± 0.000051
b = 0.009496 ± 0.000050
From this, the initial estimate of Vj is calculated by
Y = -a/b = 0.0254 ml
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Aooendix C
"^vision 4
Date: 9/87
?aae 22 of 29
o
o
o
18-
16-
14-
12-
10-
8-
6-
4-
2-
0
0.3
Y-INTERCEPT= -0.000241
SLOPE = 0.009496
R = 0.999
0.5
I
0.7
I
0.9
1.3
1.1
Va
HCI VOLUME (ml_)
1.5
I
1.7
i
1.9
Figure C-7. Plot of Fla versus Va for initial determination of Vj_.
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Appendix C
Revision 4
Date: 9/87
Page 23 or 29
Because V} >0 ana trie initial sample pH* _<7.6, calculation procedure B
(Section 3.2.11.2) is used to determine the ANC and BNC or the sample.
7.3 INITIAL ESTIMATES OF V2, ANC, BNC, AND C (SECTION 3.2.11)
From the base titration data, V2 is estimated to be 0.40 ml (the first
point with a pH* £8.2). Now that initial estimates of YI and V2 nave
been obtained, estimates of ANC, BNC, and C can be calculated.
vl ca
ANC = - = 6.9 x 10'6 eq/L
V2 Cb ,
BNC = - = 7.80 x 10'5 eq/L
Vsb
C = ANC + BNC = 8.49 x 10'5 eq/L
7.4 REFINED ESTIMATES OF Vj AND V2 (SECTION 3.2.11)
The Gran function FIC (Equation 3-1) is calculated for acid titration data
with volumes across the current estimate of Vj. The values are given
below.
Va Flc(xlO-4) Va Flc(xlO-4)
0.000
0.040
0.080
0.120
0.140
-0.26
-3.23
-6.42
-9.93
-11.6
0.160
0.260
0.280
0.380
*
-13.9
-22.8
-24.4
-33.3
FIC versus Va is plotted in Figure C-8. A regression of F^ on Va is
performed. The regression results are
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Appendix C
Revision 4
Date: 9/87
Page 24 of 29
-0.04 0 0.04
Va
0.12 0.20
I 1 L
0.28 0.36 0.44
i i i i i
i
O
T—
X
^»
o
uT
-5-
-10-
-15-
-20-
-25-
-30-
-35
Figure C-8. Plot of FIC versus Ya for Vj determination.
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Appendix C
Revision 4
Date: 9/87
Page 25 of 29
r = 0.999
a = -0.000032 ± 0.00019
b = -0.00882 ± 0.0010
A new estimate of Vj is
Vj = -a/b = -0.0036 ml
Next the Gran function F2(. (equation 3-2) is calculated from data sets
from the base titration with volumes across the current estimate of V2.
The values are given below.
vb
0.340
0.360
0.380
0.400
0.425
F2c(x lO'4) Yb
1.22 0.470
0.61 0.500
-0.087 0.540
-0.78
-2.01
F2c(x 10~4)
-4.98
-7.73
-11.1
versus VK is plotted in Figure C-9. A regression of F2c on V^ is
performed. (Data with Y^ >0.4 are not used in the regression.) The
regression results are
r = 0.999
a = 0.00126 ± 0.00003
b = -0.003348 ± 0.000073
A new estimate of V2 is
V2 = -a/b = 0.376 ml
7.5 NEW ESTIMATES OF ANC, BNC, AND C (SECTION 3.2.11)
From the new estimates of Vj and V2, new estimates of ANC, BNC, and C are
calculated.
-------
o
o
o
o"
o
CJ
3-
2-
1 -
0
-1 -
-2-
-3-
-4-
-5-
-6-
-7-
-8 -
-9 -
-10 -
-1 1 -
-12-
•13-
0
Aooencnx t
Revision 4
Date: 9/87
?aue 26 or ;
Vb
Y-INTERCEPT = 0.00 126
SLOPE= -0.003348
R = 0.999
0.34
0.38
0.42
I
0.46
0.5
0.54 0.58
NaOH VOLUME (mL)
Figure C-9. Plot or
versus VG tor V£ determination.
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Appendix C
Revision 4
Date: 9/87
Page 27 of 29
C;
sa
Vl °a A
ANC* = = 0.99 x 10~6 eq/L
V,
BNC* =
,
= 7.36 x 10'5 eq/L
= 0.065 >0.001
C* = ANC + BNC = 7.45 x 10"5 eq/L
7.6 COMPARISON OF LATEST TWO ESTIMATES OF TOTAL CARBONATE (SECTION 3.2.11)
C - C*
C + C*
Because C and C* do not agree, a new C is calculated from their average
C(new) = (C + C*)/2 = 7.97 x 10"5 eq/L
The calculations in Appendix C, Sections 7.4 through 7.6, are repeated
until successive iterations yield total carbonate values which meet the
criteria given above. The results from each iteration (including those
already shown) are given below. Note that all decimal values used are
not shown.
ANC BNC C C - C* New C
Iteration V^mL) V?(mL) (ueq/L) (ueq/L) (peq/L) C + C* (ueq/L)
1
2
3
4
5
6
7
8
9
10
0.0254
0.0036
0.0022
0.0014
0.0010
0.0008
0.0007
0.0006
0.0006
0.0005
0.400
0.377
0.376
0.376
0.375
0.375
0.375
0.375
0.375
0.375
6.9
0.99
0.60
0.40
0.28
0.22
0.18
0.16
0.15
0.15
78.0
73.6
73.4
73.3
73.2
73.2
73.1
73.1
73.1
73.1
84.9
74.5
74.0
73.7
73.5
73.4
73.3
73.3
73.3
73.3
-
0.065
0.037
0.021
0.012
0.007
0.004
0.002
0.001
0.0006
-
79.7
76.8
75.2
74.4
73.9
73.6
73.4
73.4
73.3
The final values for ANC and BNC are reported on NSWS Form 11.
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Appendix C
Revision 4
Date: 9/87
Page 28 of 29
8.0 QUALITY CONTROL CALCULATIONS
Examples of the QC calculations are described in this section.
8.1 COMPARISON OF CALCULATED ANC AND MEASURED ANC (SECTION 3.2.9.5)
For the sample analyzed in Appendix C, Section 7.0, the following data
were obtained.
initial pH = 5.09 air-equilibrated pH = 5.06
QIC = 0.59 mg/L air-equilibrated DIC = 0.36
From these data, the calculated ANC values are computed using the equation
DIC / [H+]Ki + 2 K,K9 \ Kw
[ANC]- (ueq/L) =
12,011 \[H+]2 + [H
The results are
[ANC] d = -4.2 ueq/L [ANC]C2 = -6.4 ueq/L
Then
|[ANC]Ci - CANC]C2| = 2.2 ueq/L <_ 15 ueq/L
Because [ANClci and [ANC]r,2 are in agreement, their average value is used
for comparison to the measured value.
[ANC]C-avg = -5.3 ueq/L ANC = 0.15 ueq/L
0 = |ANCC - ANC| = 5.4 ueq/L < 15 ueq/L
The calculated and measured ANC values agree, which reinforces the assump-
tion of a carbonate system.
3.2 COMPARISON OF CALCULATED AND MEASURED BNC (SECTION 3.2.9.6)
For the sample analyzed in Appendix C, Section.7.0, the following data were
obtained.
initial pH = 5.09
DIC = 0.59 mg/L
3NC = 73.1 neq/L
-------
[BNC]C (ueq/L) =
•
l
x 10
Appendix C
Revision 4
Date: 9/87
Page 29 of 29
From these data, the BNC is computed using the equation
DIC
W^MIB^M*
12,011\[H+]2
The result is
CBNC]C = 53.3 ueq/L
This value is compared to the measured value.
D = [BNC]C - BNC = -19.8 ueq/L < -10 ueq/L
This value of D is indicative of other protolytes in the system which are
contributing to the measured BNC. This might be expected because the
sample also contains 3.2 mg/L DOC.
8.3 COMPARISON OF CALCULATED TOTAL CARBONATE AND MEASURED TOTAL CARBONATE
(SECTION 3.2.9.7)
For the sample analyzed in Appendix C, Section 7:0, the following data
were obtained.
ANC = 0.15 ueq/L = 0.15 umole/L
[ANC]c-avg = -5.3 ueq/L = -5.3 umole/L
BNC = 73.1 ueq/L = 73.1 umole/L
[BNCDi = 53.3 ueq/L = 53.3 umole/L
From the DIC value, the total carbonate is calculated.
Cc = [ANC]c_avg + [BNC]c.avg = 48.0 umole/L
This calculated value is then compared to the measured value.
D = Cc - (ANC + BNC) = -25.2 umole/L < -10 umole/L
This value of D is indicative of other protolytes in the system. This
might be expected because the sample also contains 3.2 mg/L DOC. Notice
that the same conclusion was reached in the BNC comparison.
In general, noncarbonate protolytes are significant (i.e., contribute
significantly to the total protolyte concentration), when indicated by
one (or both) of the individual comparisons (ANC and BNC comparisons)
and by the total carbonate comparison.
6
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