EPA 600/4 77-012
February 1977
Environmental Monitoring Series
EPA METHOD STUDY 8, TOTAL
MERCURY IN WATER
Environmental Monitoring and Support Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
-------
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interlace in related fields.
The nine series are.
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL MONITORING series.
This series describes research conducted to develop new or improved methods
and instrumentation for the identification and quantification of environmental
pollutants at the lowest conceivably significant concentrations. It also includes
studies to determine the ambient concentrations of pollutants in the environment
and/or the variance of pollutants as a function of time or meteorological factors.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
-------
EPA-600/4-77-012
February 1977
EPA METHOD STUDY 8,
TOTAL MERCURY I N WATER
by
John Winter, Paul Britton, Harold Clements
Environmental Monitoring and Support Laboratory-Cincinnati
and Robert Kroner
Cincinnati, Ohio 45268
Prepared in part under EPA Purchase Order 5-03-4294
Project Officer
John Winter
Environmental Monitoring and Support Laboratory
Cincinnati, Ohio 45268
ENVIRONMENTAL MONITORING AND SUPPORT LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
-------
DISCLAIMER
This report has been reviewed by the Environmental Monitoring and
Support Laboratory-Cincinnati, U.S. Environmental Protection Agency, and
approved for publication. Mention of trade names or commercial products
does not constitute endorsement or recommendation for use.
ii
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FOREWORD
Environmental measurements are required to determine the quality of
ambient waters and the character of waste effluents. The Environmental
Monitoring and Support Laboratory-Cincinnati conducts research to:
0 Develop and evaluate technique to measure the presence and
concentration of physical, chemical, and radiological pollut-
ants in water, wastewater, bottom sediments, and solid wastes.
0 Investigate methods for the concentration, recovery, and
identification of viruses, bacteria, and other microorganisms
in water. Conduct studies to determine the responses of
aquatic organisms to water quality.
0 Conduct an Agency-wide quality assurance program to assure
standardization and quality control of systems for monitoring
water and wastewater.
This publication of the Environmental Monitoring and Support Laboratory,
Cincinnati, entitled: EPA Method Study 8^, Total Mercury in Water reports
the results of a joint ASTM/EPA study of a cold vapor technique for total
mercury in water, prior to acceptance by both organizations. Federal agencies,
states, municipalities, universities, private laboratories, and industry
should find this evaluative study of a selected method of analysis for
mercury of vital importance in their efforts in monitoring and controlling
mercury pollution in the environment.
Dwight G. Ballinger
Director, EMSL - Cincinnati
iii
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ABSTRACT
The Office of Research and Development, EPA, coordinates the col-
lection of water quality data to determine compliance with water quality
standards, to provide information for planning of water resources develop-
ment, to determine the effectiveness of pollution abatement procedures,
and to assist in research activities. In a large measure the success of
the pollution control program rests upon the reliability of the information
provided by the data collection activities.
The Environmental Monitoring and Support Laboratory (EMSL) in
Cincinnati, Ohio, is responsible for insuring the reliability of physical,
chemical, biological, and microbiological data generated in the water
programs of EPA. Within EMSL, the Quality Assurance Branch (QAB) conducts
interlaboratory studies for method evaluation and laboratory accreditation
programs, provides quality control samples, and develops quality control
guidelines for water quality laboratories.
This report describes one study in the series conducted by the
Quality Assurance Branch. It was completed in part by Mr. Robert C.
Kroner under EPA Purchase Order 5-03-4294.
iv
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CONTENTS
FOREWORD ill
ABSTRACT iv
FIGURES vi
TABLES vii
ACKNOWLEDGMENTS viii
PARTICIPATING LABORATORIES ix
INTRODUCTION 1
SUMMARY 2
DESCRIPTION OF STUDY
Test Design 3
Preparation of Samples A
Analysis and Reporting 5
Distribution of Samples 5
RESULTS 6
TREATMENT OF DATA
Rejection of Outliers 11
Basic Data Summaries 11
Statistical Summaries 28
Single-Analyst Precision 28
Statements of Method Precision 28
Statements of Method Accuracy 33
Two-Sample (Youden) Charts 33
DISCUSSION AND CONCLUSIONS 45
REFERENCES 46
APPENDICES
Proposed Standard Method of Test for Total Mercury in Water... 47
(Al) Disposal of Mercury Containing Wastes 57
GLOSSARY OF TERMS 60
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FIGURES
Number Page
1 Method precision for analyses in distilled water 31
2 Method precision for analyses in natural water 32
3 Method accuracy for analyses in distilled water 35
4 Method accuracy for analyses in natural water 36
5-12 Youden Plots of retained data by ampul pair 37
vi
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TABLES
Number
1 True Values for Total Mercury
2 Raw data from analyses in distilled water ..................... 7
3 Raw data from analyses in natural water ....................... 9
4-12 Data summaries by ampul for analyses in distilled water ....... 12
12-19 Data summaries by ampul for analyses in natural water ......... 20
20-21 Statistical summary ........................................... 29
vii
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ACKNOWLEDGMENTS
The authors gratefully acknowledge the hard work and cooperation of
the staff of the Quality Assurance Branch, EMSL, who assisted in the
study. They especially want to acknowledge the excellent typing and
formatting skills of Ms. Betty Smith and M. Mary Doyle and the technical
assistance and guidance of Mr. Elmo C. Julian, formerly Physics and
Chemistry Branch, EMSL, who modified some of the statistical and
graphical programs used in this study.
The staff also wishes to thank Mr. Thomas Bennett, Mercury Task
Group Chairman Committee D-19.05 of ASTM and Mr. John Kopp, Chief of the
Physical and Chemical Methods Branch of EMSL, for their cooperation and
assistance in this study.
viii
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PARTICIPATING LABORATORIES
EPA LABORATORIES
Analytical Quality Control Laboratory
Cincinnati, OH 45202
Annapolis Field Office
Annapolis, MD 21401
Environmental Protection Agency
Kansas City, MO 64108
Environmental Protection Agency
Alameda, CA 94501
Environmental Protection Agency
Charlottesville, VA 22901
Houston Facility
Houston, TX 77036
Illinois District Office
Chicago, IL 60609
Indiana District Office
Evansville, IN 47711
National Field Investigation Center
Cincinnati, OH 45268
National Water Quality Laboratory
Duluth, KN 55804
Pacific Northwest Environmental Research Laboratory
Corvallis, OR 97330
Southeast Environmental Research Laboratory
Athens, GA 30601
Water Supply Research Laboratory
Cincinnati, OH 45268
Wheeling Field Office
Wheeling, WV 26005
ix
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PARTICIPATING LABORATORIES
NON-EPA LABORATORIES
Alaska Dept. of
Environmental Conservation
Juneau, AK 99801
Allied Chemical Corp.
Brunswick, GA 31520
Allied Chemical Corp.
Riegelwood, NC 28456
Allied Chemical Corp.
Buffalo, NY 14240
Allied Chemical Corp.
Morristown, NJ 07960
Allied Chemical Corp.
Solvay, NY 13209
American Electric Power Service
Huntington, WV 25710
Arkansas Dept. of Pollution
Control & Ecology
Little Rock, AR 72209
Atlantic Richfield Company
Harvey, IL 60426
B. F. Goodrich Chemical Co.
Calvert City, KY 42029
Brandt Associates, Inc.
Newark, DE 19711
Bunker Hill Company
Kellogg, ID 82827
California Div. of Mines & Geology
San Francisco, CA 94111
Charlton Lab. Unit of MEI
Portland, OR 97207
Chicago Bureau of Water
Chicago, IL 60611
Cities Service Oil Company
Refinery Lab
Lake Charles, LA 70601
Coca Cola Company
Atlanta, CA 30318
Commonwealth of Kentucky
Dept. of Health
Frankfort, KY 40601
Commonwealth of Massachusetts
Lawrence Experiment Station
Lawrence, MA 01843
Commonwealth Laboratory, Inc.
Richmond, VA 23223
Diamond Shamrock Chemical Co.
Mobile, AL 36614
Dow Chemical
Palquemine, LA 70764
Edna Wood Labs., Inc.
Houston, TX 77021
Environment Canada
Canada Centre for Inland Waters
Burlington, Ontario, Canada
Federal Paper Board Co., Inc.
Riegelwood, NC 28456
Froehling & Robertson
Richmond, VA 23261
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PARTICIPATING LABORATORIES
NON-EPA LABORATORIES
(Continued)
General Testing Labs., Inc.
Kansas City, MO 64108
Georgia Dept. of Natural Resources
Atlanta, GA 30334
Gulf Research & Development Co.
Pittsburgh, PA 15230
Holston Defense Corp.
Kingsport, TN 37662
Huntington Alloys
Huntington, WV 25720
Hydro Research Labs.
Pontiac, MI 48058
Illinois Environ. Protection Agcy.
Carbondale, IL 62901
Illinois Environ. Protection Agcy.
Champaign, IL 61820
Indiana State Board of Health
Indianapolis, IN 46206
Industrial Testing Labs
St. Louis, MO 63104
Interstate Sanitation Commission
New York, NY 10019
Kern-Tech Laboratory
Baton Rouge, LA 70818
Koppers Company, Inc.
Monroeville, PA 15146
Los Angeles Dept. of Water & Power
Los Angeles, CA 90051
Louisiana State Dept. of Health
New Orleans, LA 70160
Maine Dept. of Environmental
Improvement Commission
Augusta, ME 04330
Maryland Dept. of Health
Baltimore, MD 21218
Maryland Water Resources Admin.
Annapolis, MD 21401
Michigan Dept. of Public Health
Lansing, MI 48914
Ministry of the Environment
Rexdale, Ontario, Canada
Montana Bureau of Mines & Geology
Butte, MT 59701
Moutrey & Associates, Inc.
Tulsa, OK 74145
National Institute of Occupational
Safety & Health
Cincinnati, OH 45202
North Carolina Dept. of Health
& Economic Resources
Raleigh, NC 27611
NUS Corporation
Pittsburgh, PA 15205
Oilwell Research, Inc.
Long Beach, CA 90831
xi
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PARTICIPATING LABORATORIES
NON-EPA LABORATORIES
(Continued)
Olin Corporation
Mclntosh, AL 36553
Olin Corporation
Pisgah Forest, NC 28768
Pennsylvania Dept. of Environ.
Resources
Erie, PA 16505
Pennwalt Corporation
King of Prussia, PA 19406
Pennwalt Corporation
Calvert City, KY 42029
Philadelphia Water Dept.
Philadelphia, PA 19136
Ralston Purina Company
St. Louis, MO 63188
St. Louis Testing Labs.
St. Louis, MO 63103
Seattle Metro Water Quality Lab
Seattle, WA 98119
Serco Laboratories
Minneapolis, MN 55406
South Dakota School of Mines
& Technology
Rapid City, SD 57701
Stewart Labs., Inc.
Knoxville, TN 37921
Tenco Hydro/Aerosciences
Countryside, IL 60525
Tennessee Dept. of Public Health
Nashville, TN 37319
Tennessee Valley Authority
Chattanooga, TN 37401
Texas State Dept. of Health
Austin, TX 78756
U.S. Air Force
Environmental Health Lab
Kelly AFB, TX 78241
U.S. Dept. of the Army
Corps of Engineers
Cincinnati, OH 45201
U.S. Geological Survey
Analytical Methods Research, WRD
Denver, CO 80225
U.S. Geological Survey
Harrisburg, PA 17108
University of Maine
Orono, ME 04473
Utah Environmental Laboratory
Port Hardy, B.C., Canada
Utah State Dept. of Social Services
Salt Lake City, UT 84113
Ute Research Laboratories
Fort Duchesne, UT 84026
Vermont Dept. of Water Resources
Monpelier, VT 05602
Washington State University
College of Engineering
Pullman, WA 99163
xii
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PARTICIPATING LABORATORIES
NON-EPA LABORATORIES
(Continued)
West Coast Technical Services, Inc.
San Gabriel, CA 91776
West Virginia Dept. of Health
Environmental Health Services Lab
South Charleston, WV 25303
West Virginia Dept. of Natural
Resources
Charleston, WV 25303
West Virginia Dept. of Natural
Resources
Elkins, WV 26241
Westinghouse Corporation
Pittsburgh, PA 15235
Westinghouse Corporation
Madison, PA 15663
Westinghouse Corporation
Elmira, NY 14900
Wilson & Company
Salina, KS 68401
xiii
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INTRODUCTION
The various analytical laboratories of the U.S. Environmental
Protection Agency gather water quality data to provide information on
water resources, to assist research activites, and to evaluate pollution
abatement activities. The success of these pollution control activities
depends upon the reliability of the data provided by the laboratories,
particularly when legal action is involved.
The Environmental Monitoring and Support Laboratory-Cincinnati
(EMSL, formerly Methods Development and Quality Assurance Research Labora-
tory) of EPA was established to conduct EPA's quality assurance program
for the water laboratories and to assist EPA laboratories in the choice
of methods for physical, chemical, biological and microbiological analyses.
The quality assurance program of EMSL is designed to maximize the reliability
and legal defensibility of all water quality information collected by EPA
laboratories. The responsibility for these activities of EMSL is assigned
to the Quality Assurance Branch (QAB). This study is one of the QAB
activities.
Prior to this method evaluation study, the research chemists of EMSL,
assisted by other chemists in EPA, had proposed a method of measurement
for total mercury in natural water and wastewaters. The method developed
after considerable study included an acid-permanganate-persulfate digestion
at 95°C for two hours followed by reduction and measurement of mercury in
the vapor phase at 253.7 nm.
Since EPA chemists are participating members of the D-19 Committee
on Water of the American Society for Testing and Materials, the same
method was proposed to the D-19 Committee for use in the Annual Book of
ASTM Standards, Part 31, Water. It was logical therefore to propose a
joint EPA/ASTM study for mercury in water. This report describes the
study and provides statements of precision and accuracy for the method.
-------
SUMMARY
The Quality Assurance Branch of the Environmental Monitoring and
Support Laboratory conducted a joint EPA/ASTM interlaboratory study on
the cold vapor technique for mercury in natural waters.
The method evaluated in this study is that described by Kopp, Long-
bottom, and Lobring (1) which requires a vigorous digestion with acid
permanganate, potassium persulfate and heat (95°C) to effect complete
oxidation of organically bound mercury prior to reduction and measurement
by absorption at 253.7 nm.
Sample concentrates were prepared at similar, but slightly different,
concentrations of mercury. An aliquot of each concentrate was added to
distilled water and natural water samples at concentrations of 0.2-10 ug
of mercury/liter. One mercury measurement was made on the natural water
as background and one measurement each on the distilled water and natural
water samples with the added increment. Recoveries from the natural
water samples were calculated by difference. Recoveries for all concen-
trations were compared and significant statistical measures such as
standard deviation, mean recovery, etc., were calculated. The following
equations provide the precision and accuracy which may be expected in
routine work:
Distilled Water;
Precision S = 0.2454 + 0.2922 X
Sr = 0.3117 + 0.0718 X
Accuracy
Mean Recovery, X = 0.2028 + 0.9517 (cone)
Natural Water;
Precision S = 0.1661 + 0.3647 X
Sr = 0.0465 + 0.1379 X
Accuracy
Mean Recovery, X = 0.1373 + 0.9508 (cone)
-------
DESCRIPTION OF STUDY
The study design was based on Youden's original plan (2) for collab-
orative evaluation of precision and accuracy for analytical methods.
According to Youden's design, samples are analyzed in pairs, and each
sample of a pair has a slightly different concentration of the constituent.
The analyst is directed to do a single analysis and report one value for
each sample, as if for a normal routine sample.
In this study, samples were prepared as concentrates in sealed glass
ampuls and presented to the analyst with complete instructions. The
analyst was required to add an aliquot of each concentrate to a volume of
distilled water and to a volume of natural water of any kind. Analysis
in distilled water evaluates the proficiency of the analyst to use the
method on a sample free of interferences; analysis in natural water
(rivers, lakes, estuaries) is intended to reveal interferences in the
method. Four pairs of samples were used. One pair contained mercury
near the minimum detectable limit of 0.2 yg/liter; a second pair contained
mercury at an intermediate level of 0.5-0.6 vg/liter level and the latter
pairs contained mercury at levels of 3-10 yg/liter.
Test Design
A summary of the test design, using Youden's non-replicate technique
for x and y samples is given below:
1) Eight samples, prepared as stable concentrates in sealed glass
ampuls, were presented to the analyst as unknowns.
2) When the analyst was ready to start the analysis, the ampuls
were opened and an aliquot diluted to volume in distilled water
and in a natural water according to instructions.
3) Four levels of mercury concentration (four pairs of samples)
were analyzed to cover the levels observed in natural waters.
A) Each sample was analyzed once only.
5) Natural water samples were analyzed with and without added
increment and the added level determined by difference.
Recoveries from distilled water and natural waters were compared.
Precision and accuracy were calculated and interferences were observed.
-------
Preparation of Samples
Sample concentrates were prepared by dissolving precisely-weighed
amounts of reagent grade chemicals in high purity water* to produce
accurate concentrations of organic and inorganic mercury. Each sample
contained the same ratio of inorganic to organic mercury (42%:58%) as
mercuric chloride and methyl mercury chloride, respectively. The concen-
trates were preserved with 0.15% redistilled nitric acid and checked by
repeated analysis for a period of three months prior to distribution.
These analyses served to confirm both the calculated concentrations and
sample stability. Analyses of the samples by an outside laboratory also
confirmed the concentrations.
When diluted to volume according to the instructions, the samples
contained the following concentrations of mercury:
TABLE 1
True Values for Total Mercury**
Sample Concentration of Mercury
Vg/liter
1
2
3
4
5
6
7
8
0.21
0.27
0.51
0.60
3.4
4.1
8.8
9.6
* Prepared by passage of distilled water through a four-cartridge
Millipore Super-Q system.
** The concentrations are the actual levels calculated and added. They
are not based on analysis, the latter being used for verification
only.
-------
Analysis and Reporting
The distilled water - natural water spike technique was used in this
study. Each analyst was instructed to dilute separate 5.0 ml aliquots
of each concentrate to one liter with distilled water and a natural or
wastewater of his choice. To insure sample stability the analyst was
also instructed to add 1.5 ml of redistilled nitric acid per liter during
sample preparation. Accurate measurement of mercury in distilled water
confirmed the analyst's ability to measure mercury in a sample free of
interferences. A difference in the recovery of mercury from distilled
water as compared to the recovery of mercury from natural water indicated
the presence of interferences.
Distribution of Samples
An invitational memorandum announced the study to each EPA Region in
September, 1972. The study was also announced in EPA's Analytical Quality
Control Newsletter which is circulated to about 7,000 technical offices
of government and private agencies in the United States and Canada.
One-hundred and one laboratories from EPA, other Federal, State and
local agencies, Canadian groups, universities and private industry responded
and participated. After a pre-selected cutoff date, beyond which no
further requests were answered, samples were packed and shipped.
Each collaborator was sent 1) a set of eight ampuls, 2) instructions
for sample preparation, 3) a copy of the analytical procedure to be used,
and 4) duplicate report sheets. Participants were allowed fifty days to
complete the analyses and report the data. All data returned within the
prescribed time were included in this report; data reported later that
the cutoff date were omitted.
-------
RESULTS
Tables 2 and 3 present all raw data received, identified by labora-
tory and analyst codes.
-------
TABLE 2
Raw Data from Analyses for Total Mercury Increment
In Distilled Water
AMPUL AMPUL AMPUL AMPUL AMPUL AMPUL
1 2 3 I. 5 6
INCREMENT, UG/L 0.21 0.27 0.51 0.60 3.4 "i. 1
AMPUL
7
AMPUL
9.6
LAB
NO.
ANALYST
NO.
101
105
106
110
112
117
122
12J
124
125
137
11(2
li»5
US
152
157
169
180
180
180
182
181*
185
190
195
201*
212
230
233
233
253
259
261
2E2
267
311
324
329
352
356
T74
i|22
1)36
437
14 41
l»i)2
1(1(5
1(1(6
447
1(1(8
4?2
457
It67
1(68
U71
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
3
1
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
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0
0
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1
3
0
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1
0
0
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.50
.07
.61
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.38
.10
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.21
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.15
.20
.23
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.58
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.80
.1)8
.20
.20
.1)0
.50
.1)3
.80
.60
.OOR
.50
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.00
.46
.1)0
.50
.11)
.35
.1)1)
.1)0
.11
.20
.90
.29
.55
.30
0
0
0
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1
0
0
0
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0
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0
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10
1
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0
.23
.50
.21
.31)
.31
.31
.20
.36
.00
.10
.27
.30
.65
.29
.35
.20
.30
.32
.1)1)
.17
.20
.29
.20
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.80
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.20
.60
.00
. 60R
.1)1)
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.95
.50
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.16
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.50
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.90
.26
.70
.20
0
0
0
0
0
0
0
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1
0
0
0
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0
0
0
0
0
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7
5
6
2
0
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1
0
0
.50
.60
.50
.35
.52
.56
.1)6
.1)0
.58
.00
.10
.50
.50
.75
.53
.58
.30
.50
.55
.53
.38
.38
.52
.1)0
.10
.1)2
.35
.52
.00
.05
.60
.1)5
.00
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.68
.80R
.l)OR
.28R
.30
.50
.53
.98
.50
.32
.25
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.71)
.1)8
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0
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.81
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.81
.67
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.50
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.70
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.20
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.70
.52
.26
.60
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.1)5
.1(5
.50
.OOR
.i)6R
.75
.50
3.80
3.80
J.50
2.00
3.10
3.20
4.20
4.1(0
1.1)8
1.60
3.10
3.20
3.30
3.60
3.1)0
5.70
5.1U
3.1)3
3.50
3.50
3.10
5.10
5.20
6.30
3.80
5.1)0
5.30
4.70
4.85
4.1(0
3.10
3.20
5.30
2.10
120. OOR
3.20
2.28
l).00
1.20
4.91
i(.87
5.50
2.1)5
l.UO
5.20
5.50
5.90
2.1)0
1.50
2.80
28. OOR
2.75
5.20
2.00
l).30
4.50
It. 50
2.50
4.30
4.20
4.80
5.10
1.25
4.40
3.50
3.50
3.80
4.10
4.20
4.20
4.27
4.70
4.40
4.30
3.70
3.73
4.10
7.70
4.38
4.20
4.10
5.60
4.95
6.00
3.60
3.80
4.00
2.60
148. OOR
3.40
5.56
4.20
0.90
5.86
5.89
4.50
3.10
1.65
4.00
4.30
4.30
4.10
2.10
3.40
30. OOR
3.21
3.80
2.90
8.
9.
10.
6.
8.
8.
9.
9.
3.
4.
7.
9.
8.
9.
8.
8.
10.
10.
5.
9.
8.
7.
8.
13.
6.
8.
9.
10.
10.
11.
7.
9.
8.
4.
328.
8.
4.
7.
2.
10.
11.
9.
7.
3.
9.
9.
9.
7.
7.
63.
6.
8.
6.
35
30
00
00
70
70
40
60
30
40
80
00
00
30
50
20
00
00
00
10
20
43
50
20
80
60
00
60
05
00
40
40
40
20
OOR
00
56
50
00
99
88
50
50
35
00
00
30
90
30
OOR
85
30
20
9.60
9.60
11.00
6.20
9.70
9.00
10.00
11.00
4.25
4.80
8.30
9.2&
7.60'
9.90
9.30
8.90
13.30
13.25
10.00
10.00
9.00
7.89
8.90
13.50
8.48
9.10
9.20
10.80
9.95
10.00
8.10
8.40
9.10
4.60
382. OOR
9.10
10.40
7.70
2.30
11.85
12.80
10.00
7.30
3.59
9.80
9.50
9.80
7.20
4.80
7.50
68. OOR
8.80
9.00
8.80
R • REJECTED
-------
TABLE 2
(Continued)
Raw Data from Analyses for Total Mercury Increment
In Distilled Water
AMPUL AMPUL AMPUL AMPUL AMPUL AMPUL
1 2 3 4 5 6
INCREMENT, UG/L 0.21 0.27 0.51 0.60 3.4 4 . 1
AWPUL
7
AfPUL
8
9.6
LAB ANALYST
NO. NO.
472 1
475 1
478 1
1)81 1
U86 1
1489 1
492 1
496
500
502
503
504
508
509
510
511
512
513
51U
515 1
516 1
517 1
518 1
519 1
520 1
521 1
522 1
523 1
52l» 1
525 1
526 1
527 1
528 1
529 1
530 1
531 1
532 1
533 1
534 1
535 1
0.
0.
0.
0.
0.
0.
0.
0.
0.
1.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
1.
0.
1.
0.
0.
0.
0.
0.
0.
0.
0.
1.
0.
3.
12.
0.
4.
05
20
80
50
32
20
60
26
83
00
15
52
60
35
75
23
50
43
33
20
00
20
00
37
41
41
20
80
45
20
40
00
00
75R
10R
23
10R
0.
0.
0.
0.
0.
0.
0,
0,
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
1.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
1.
5.
14.
0.
4.
71
30
30
45
36
17
58
32
63
90
15
40
70
25
80
28
79
30
20
91
20
00
25
41
16
30
BO
50
30
26
40
50
20
84
OOR
30R
04
80R
1.
0.
1.
0.
0.
0.
1.
0.
1.
0.
1.
0.
1.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
1.
0.
0.
0.
1.
1.
0.
0.
1.
1.
0.
3.
7.
0.
0.
5.
37
50
20
82
52
34
10
58
20
65
00
40
80
60
65
90
54
48
28
58
20
36
40
00
65
61
50
10
10
35
41
20
00
45
92R
OOR
65
OU
70R
0
0
0
0
0
0
1
0
1
1
0
0
1
1
0
1
0
0
0
0
0
0
0
1
0
0
0
0
1
0
0
0
2
0
1
7
0
D
3
.34
.50
.60
.92
.62
.51
.14
.70
.20
.20
.95
.70
.20
.80
.65
.00
.65
.52
.20
.54
.1(0
.18
.50
.00
.98
.69
.60
.80
.10
.35
.52
.30
.50
.35
.39
.OOR
.88
.03
.00
D
3
It
3
3
ti
3
3
4
3
3
it
3
3
3
3
3
3
3
3
2
3
4
3
3
3
3
3
L
3
2
3
6
1
23
11
3
0
4
67
50
20
08
50
00
10
50
20
45
36
10
10
40
00
50
50
20
30
30
00
00
00
80
50
81
50
60
70
80
60
20
25
90
10R
30
30
20
80
1.11
U.I4"
4.60
5.08
4.20
5.90
3.70
4.10
5.40
3.90
4.22
4.60
3.30
3.80
4.10
4.10
3.90
It. 10
4.50
3.60
4.00
5.00
4.53
4.60
4.29
4.20
4. 50
5.20
4.00
3.30
7.50
8.00
10.60
5.40
16.30R
6.70
0.20
3.30
3
8
9
10
9
13
6
8
12
7
8
11
7
8
8
9
9
9
10
6
8
9
11
e
10
9
10
9
8
7
3
12
36
20
9
0
10
.U
.80
.40
.75
.00
.00
.00
.30
.00
.00
.56
.60
.70
.10
.70
.00
.30
.10
.00
.30
.60
.00
.00
.40
.51
.10
.20
.20
.00
.20
.60
.00
.40R
.00
.80
.55
.00
1
10
10
11
9
13
9
9
14
S
S
12
7
S
9
9
9
9
12
7
11
10
13
8
11
10
11
9
8
8
u
15
5
18
25
9
0
10
.18
.00
.40
.05
.90
.00
.60
.00
.00
.10
.34
. 50
.80
.20
.50
.00
.60
.60
.00
.50
.20
.00
.00
.80
.96
.00
.40
.70
.20
.00
.10
.75
.20
.60
.00
.30
.58
.00
REJECTED
-------
TABLE 3
Raw Data from Analyses for Total Mercury Increment
in Natural Water
AMPUL AMPUL AMPUL AMPUL AMPUL AMPUL
1 2 3 4 5 6
INCREMENT, UG/L 0.21 0.27 0.51 0.60 3.4 4. 1
AMPUL
7
AMPUL
9.6
LAB
NO.
ANALYST
NO.
101
105
106
110
112
117
122
123
121.
125
137
142
1U5
148
152
157
169
1814
185
190
20U
212
230
233
233
253
259
261
262
267
311
324
329
352
356
37ii
422
1.36
1.1.1
1.1.2
It 43
1.1.6
447
448
1.52
457
1(68
471
472
475
478
481
486
489
492
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0. 15
0.20
0.50
0.07
0.30
0.10
0.30
1.00
0.10
0.22
0.40
0.30
0.29
0.35
0.10
0.20
0.23
0.22
0.20
0.32
0.14
0.80
0.48
0.20
0.20
0.00
0.30
0.44
0.80
2.20R
0.39
0.64
0.10
1.27
0.27
0.50
0.15
O.UO
0.56
0.40
0.26
0.50
0.90
0.49
0.20
0.08
0.20
1.20
0.48
0.30
0.10
C.44
0.30
0.50
0.21
0.3S
0.26
0.20
0.27
1.00
0.11
0.27
0.15
0.30
O.i5
0.20
0.23
0.31
0.26
0.20
0.16
0.19
0.80
0.49
0.20
0.21
0.80
0.20
0.61
1.00
7. 5 OR
0.10
0.59
0.50
1.05
0.40
0.50
0.15
0.42
0.32
0.50
0.24
0.20
0.40
1.10
1.00
0.10
0.65
0.20
0.80
0.53
0.35
0.16
0.46
0.64
0.60
0.50
0.35
0.42
1.06
0.20
0.57
1.00
0.11
0.50
0.50
0.22
0.55
0.60
0.40
0.46
0.51
0.47
0.37
0.35
0.40
1.00
1.05
0.70
0.45
0.20
0.40
O.E9
8. COR
4.20R
0.10
2.40
0.40
1.46
0.82
0.50
0.26
0.62
0.66
0.70
0.34
O.SO
0.50
4.00
0.28
0.20
1.44
O.JO
1.20
0.93
0.52
0.35
1.10
0.69
0.80
0.50
1.00
0.46
0.38
0.60
0.75
1.00
0.22
0.56
0.50
0.80
0.60
0.50
0.61
0.64
0.53
0.49
0.72
0.45
1.00
0.95
0.20
0.58
10.00R
0.60
0.66
8.70R
1.60
0.10
2.30
0.30
1.32
0.91
0.50
0.25
0.60
0.49
1.00
0.62
0.50
3.900
0.35
0.30
0.44
0.40
1.20
0.96
0.60
0.46
0.90
3.60
4.00
3.50
2.10
3.30
4.60
3.60
4.40
4.20
0.85
1.80
3.30
3.00
2.80
3.40
5.50
3.60
3.20
2.94
3.30
2.79
3.60
2.90
4.70
4.85
5.40
3.10
3.00
3.70
2.60
125. OOR
1.70
0.13
4.20
3.70
5.06
4.84
1.36
3.40
3.80
3.50
2.40
2.10
2.80
30. OOR
3.50
2.10
0.64
2.10
3.80
3.4S
3.50
4.00
3.20
4.30
5.00
4.00
2.50
4.40
5.00
4. 00
4.70
4.80
0.83
2.30
3.70
3.7(1
4.10
4.20
4.00
3.90
5.77
4.20
2.70
4.60
3.50
5.60
4.95
5.00
5.60
5.20
4.50
2.70
155. OOR
3.90
0.77
4.20
1.70
5.82
1.70
4.00
5.90
4.30
3.00
5.00
3.40
35. OOR
4.00
5.10
1.10
2.20
4.49
4.58
4.30
5.60
4.03
8.43
8.00
9.50
6.10
8 .40
10.30
8 .20
9.70
9.80
1.88
4.50
7.80
8.30
10.40
8.80
8.50
8.10
8.70
7.34
8.40
6.36
9.10
10.70
10.60
10.05
12.00
7.40
8.40
9.00
3.90
340. OOR
8.00
2.45
7.80
3.00
11.98
3.42
9.40
8.50
9.00
6.60
7.30
66. OOR
8.30
6.30
3.22
4.80
9.00
11.03
8.60
15.00
8.30
9.40
9.10
10.50
6.20
.9.20
12.80
8.70
9.70
11.00
1.98
5.00
8.30
8.30
9.60
9.50
9.00
9.20
7.80
8.80
6.72
9.50
10.80
9.95
10.00
8.10
7.80
10.00
4.00
379. OOR
8.50
3.35
8.00
4.10
13.27
3,52
10,00
9,50
12,00
6,20
3,80
7,50
72, OOR
9,40
9,00
1,18
5,10
10.00
11.98
9.80
14.00
9.00
R - REJECTED
-------
TABLE 3
(Continued)
Raw Data from Analyses for Total Mercury Increment
in Natural Water
AMPUL AMPUL AMPUL AMPUL AMPUL AMPUL AMPUL AMPUL
123U5678
INCREMENT, UG/L 0.21 0.27 0.51 0.60 3.1* I*. 1 8.8 9.6
LAB ANALYST
NO. NO.
<(96
500
503
501)
508
510
511
512
51k
515
516
517
518
519
520
521
522
523
52U
525
526
527
529
530
531
552
533
531.
535
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
1.
0.
0.
0.
0.
0.
0.
1.
3.
it.
1.
0.
k.
30
22
25
15
1(7
00
80
21*
i>0
30
22
00
20
00
18
03
16
20
45
20
00
35R
75R
80R
00
70R
0.31
0.00
0.65
0.80
0.35
0.25
1.20
0.28
0.40
0.33
0.1)14
0.78
0.40
1.00
0.32
0.00
0.06
0.25
1.00
0.50
0.30
0.2U
0.50
0.30
2.09R
5.75R
2.60R
0.07
3.80R
0.60
o.uo
1.10
0.60
0.95
0.1)0
l.liO
0.56
0. 50
0.56
0.77
0.1)0
0.1)0
1.00
0.65
0.20
0.32
0.50
1.1)0
1.10
O.iiO
0.1)1)
0.75
0.30
18.U3R
7.50R
1.70
0.01
14.30R
0.72
0.1.0
1.05
0.70
1.50
1.50
0.65
0.50
0.61)
0.73
0.16
0.50
1.00
1.10
0.1)0
0.35
0.60
1.20
1.30
0.50
0.55
1.00
0.30
2.66R
7.50R
1.70
0.00
I..20R
3.70
3.00
3.95
3.1)1
3.80
J.15
3.55
3.50
2.80
3.30
4.20
2.10
3.1.0
l).00
3.80
3.80
2.96
3.1)0
3.00
It. 60
2.50
2.80
5.00
7.20
18.86R
12.50
2.90
0.16
3.50
I.
tl
I.
ti
1)
3
1*
(1
l)
1)
1)
3
1.
1)
1)
It
3
1)
>.
5
3
3
6
21
19
2
0
3
.10
.10
.25
.22
.30
.73
.50
.00
.00
.10
.50
.10
.00
.00
.50
.80
.1.6
.10
.30
.20
.20
.50
.50
.DOR
.OOR
.1)0
.17
.90
8.50
12.00
9.1.5
7.76
11.20
8.10
8.35
8.50
8.90
9.10
11.00
6.50
8.60
9.00
11.00
8.20
7.21
8.90
13.80
9.00
6.80
7.50
15.75
28.00
21.30
13.00
0.53
7.20
9
17
9
a
11
10
9
9
9
11
7
11
9
12
8
7
9
10
9
7
8
1U
5
15
26
12
0
7
.20
.00
.05
.31.
.80
.70
.10
.60
.60
.00
.60
.80
.00
.00
.90
.96
.80
.70
.80
.30
.10
.50
.1)0
.1)0
.30
.60
.51)
.20
REJECTED
10
-------
TREATMENT OF DATA
Rejection of Outliers
This study, done at low and fractional yg/liter levels, produced
some data which were orders of magnitude away from the true values.
These extraneous values had to be eliminated before beginning any data
evaluations. If these were not removed, the deviations in the data would
indicate a misleadingly large standard deviation for the method. To
prevent this from happening, those values which were further than four
standard deviations from the mean, as calculated from all data, were
discarded as outliers. Assuming a normal distribution, there is a 99.994%
probability that the rejected data were properly discarded.
After elimination of unreasonable data, it was necessary to remove
the remaining extreme values which had only a small chance of validity
and which would make a significant change in the precision and accuracy
values for the tested levels of mercury. These abnormal values are a
part of the routine data in every interlaboratory study, resulting from
chemical, instrumental, and analyst error. These outliers were rejected
by applying the two-tailed Student's t test to all values at a 99% proba-
bility level. This gave a 99 to 1 assurance that the data rejected were
indeed true outliers and should be discarded.
As the spread of valid data increases, fewer outliers are rejected
because of a large standard deviation in the denominator of the t test.
Similarly, when the spread of valid data is very small the t test is more
powerful and more of the outliers are detectable. In either case, the
rejected values should be considered true outliers and the analytical
conditions should be carefully reviewed for the cause of error.
Basic Data Summaries
Complete data summaries are given in Tables A through 19. Each
Table provides a statistical evaluation of the data for a single concen-
trate spiked into one type of water. With the exception of "N, ALL DATA"
and "MEAN, ALL", the statistical parameters are based on the data remaining
after the rejection of outliers (retained data).
In addition to the statistical measurements, all data are ranked in
ascending order and retained data are presented in a histogram using Vn
cell divisions. Each X in the histogram represents one analytical result
for 1-15 values/cell. When more than 15 values occur per cell, only 15
X's are printed but the actual number of values included in the cell is
printed to the left.
11
-------
TABLE
Data Summary by Ampul, Analyses for
Total Mercury in Distilled Water
AMPUL 1 INCREMENT « 0.21 UG/LITER ORGANIC * INORGANIC MERCURY
N.ALL DATA 91
TRUE VAL. 0.21
MEAN,ALL
MEANtRET.
MEDIAN
ACCURACY
0.6515*
0.41770
0.38000
98.90502
RANGE 1.60000 COEF. VAR. 0.6686*
VARIANCE 0.07800 SKEMNESS 1.38637
STD. OEV. 0.27929 NO. OF CELLS 9
CONF. LIM. ±0.55367 (95 PCT)
PCT RELATIV/E ERROR
DATA IN ASCENDING ORDER
0.00
0.05
0.07
0.10
0.10
0.10
0.11
0.11
0.1*
0.15
0.15
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.21
0.21
0.22
0.22
0.23
0.23
0.23
0.2*
0.28
0.29
0.30
0.30
0.32
0.35
0.35
0.37
0.37
0.38
0.38
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.41
0.41
0.43
0.43
0.43
0.44
0.45
0.46
0.48
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.52
0.55
0.58
0.60
0.60
0.61
0.75
0.80
0.80
0.80
0.80
0.83
0.90
1.00
1.00
1.00
1.00
1.00
1.00
1.60
3.00R
3.75R
4.10R
12.10R
MIDPOINT FREO. HISTOGRAM
RETAINED DATA ONLY
0.0889
0.2667
G.kkkk
0.6222
0.8000
0.9778
1.1556
1.3333
1.5111
11
29
28
5
6
7
0
0
1
xxxxxxxxxxx
xxxxxxxxxxxxxxx
xxxxxxxxxxxxxxx
xxxxx
xxxxxx
xxxxxxx
R = REJECTED DATA
12
-------
TABLE 5
Data Summary by Ampul, Analyses for
Total Mercury in Distilled Water
AMPUL 2 INCREMENT - 0.27 U3/LITFR ORGANIC
INORGANIC MERCURY
N.ALL DATA 92
TRUE VAL. 0.27
MFAN.ALL 0.80728
«LDlAN
ACCURACY
RAN3E
VARIANCE
STD. DEV.
0.44965 CONF. LIM.
0.33000
66.54010 °CT RELATIVE ERROR
1.79999 COEF. VAR. 0.72238
0.10551 SKEWNESS 2.02945
0.32482 NO. OF CELLS 9
+0.64026 (95 PCT)
DATA IN ASCENDI^S ORDER
0.04
0.10
0.15
0. 16
0. 16
0.17
0.17
0. 19
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.21
0.21
0.23
0.25
0.25
0.26
0.26
0.27
0.27
0.28
0.29
0.29
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.31
0.31
0.32
0.32
0.34
0.35
0.35
0.35
0.36
0.36
0.36
0.40
0.40
0.40
0.40
0.40
0.41
0.44
0.44
0.45
0.49
0.50
0.50
0.50
0.50
0.50
0.50
0.58
0.60
0.63
0.65
0.70
0.71
0.79
0.80
0.80
0.80
0.80
0.90
0.90
0.91
0.95
L.OO
1.00
1.00
L.44
1.70
1.84
4. SOP
5.OOP
10.60R
U.30R
MIDPOINT FREO. HISTOGRAM
RETAINED DATA ONLY
O.lltOO
0.3liOO
0.5400
0.7400
0.9400
1.1400
1.3400
1.5400
1.7400
22
35
13
8
7
0
0
1
2
XXXXXXXXXXXXXXX
XXXXXXXXXXXXXXX
xxxxxxxxxxxxx
xxxxxxxx
xxxxxxx
X
XX
R = REJECTED DATA
13
-------
TABLE 6
Data Summary by Ampul, Analyses for
Total Mercury in Distilled Water
AMPUL 3 INCREMENT * 0.51 UG/LITFR 3RGANIC «• INORGANIC MERCURY
N.ALL DATA 91*
TRUE VAL. 0.51
MEAN,ALL
MEAN,RET.
MEDIAE
ACCURACY
1.02929
0.65344
0.52000
28.12685
RANGE
VARIANCE
STD. DEV.
CONF. LIM.
2.25999
0.14130
0.37590
COEF. VAR.
SKEWNESS
NO. OF CELLS
0.57526
1.70852
9
+0.74937 (95 PCT)
PCT RELATIVE ERROR
DATA IN ASCENDING ORDER
0.04
0.10
0.20
0.25
0.27
0.28
3.30
0.30
0.32
0.34
0.35
0.35
0.35
3.36
0.38
3.38
0.38
0.40
0.40
0.40
0.40
0.40
0.41
0.42
0.45
0.45
0.45
0.46
0.4B
3.48
0.50
0.50
0.50
0.50
3.50
0.50
0.50
0.50
0.50
0.50
0.52
0.52
0.52
0.52
0.53
0.53
0.54
0.55
0.56
0.56
0.58
0.58
0.58
0.58
0.60
0.60
0.60
0.61
0.65
0.65
0.65
0.65
0.68
0.70
0.75
0.82
0.90
0.98
1.00
1.00
1.00
1.00
1.00
1.00
1.05
1.10
1.10
1.10
1.10
1.20
1.20
1.20
1.37
1.53
1.74
1.80
2.30
3.80R
3.92R
5.40ft
5.70R
6.28R
7.00R
7.80R
MIDPOINT FREQ. HISTOGRAM
RETAINED DATA ONLY
0.1656 6 XXXXXX
O.U167 Ul XXXXXXXXXXXXXXX
0.6678 18 XXXXXXXXXXXXXXX
0.9189 9 XXXXXXXXX
1.1700 8 XXXXXXXX
1.1*211 2 XX
1.6722 1 X
1.9233 1 X
2.171*1* 1 X
REJECTED DATA
14
-------
TABLE 7
Data Summary by Ampul, Analyses for
Total Mercury in Distilled Water
41PUL 4 INCREMENT = 0.60 UG/LITFR DRGANIC *• INORGANIC MERCURY
N.ALL DATA 93
TRUt VAL. 0.60
MEAN,ALL 1.15289
MEAN,SET. 0.74386
MEDIAN 0.60000
RANGE
VARIANCE
STO. DEV.
CONF. LIM.
2.97000
0.21709
0.46593
+0.92354
COfcF. VAR.
SKEWNESS
NO. OF CELLS
195 PCT)
0.62637
2.34514
9
ACCURACY
23.97704 PCT RELATIVE ERROR
DATA IN ASCENDING ORDER
9.03
3.18
0.20
0.20
0.20
0.22
0.26
0.30
0.34
35
35
0.40
0.40
0.45
0.45
0.45
0.49
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.51
0.51
0.52
3.52
0.52
0.53
3.55
0.55
0.56
0.56
0.57
0.57
0.60
0.60
0.60
0.60
0.60
0.60
0.60
0.60
0.60
0.61
0.62
0.64
0.64
0.64
0.64
0.65
0.67
0.69
0.70
0.70
0.70
0.70
0.75
0.80
0.80
0.80
0.81
0.81
0.83
0.88
0.92
0.94
0.95
0.95
0.98
1.00
1.00
1.00
1.00
1.10
1.14
1.20
1.20
1.20
1.28
1.29
1.39
1.60
1.80
2.30
2.50
3.00
4.OOP
6.46R
7.00R
8.90R
15.UOR
MIDPOINT FREO. HISTOGRAM
RETAINED DATA OMLY
0.1950 11 XXXXXXXXXXX
0.5250 U2 XXXXXXXXXXXXXXX
0.8550 22 XXXXXXXXXXXXXXX
1.1850 7 XXXXXXX
1.5150 2 XX
1.81*50 1 X
2.1750 1 X
2.5050 1 X
2.8350 1 X
'< = REJECTED DATA
15
-------
TABLE 8
Data Summary by Ampul, Analyses for
Total Mercury in Distilled Water
AMPUL 5 INCREMENT = 3.4 UG/LITE* ORGANIC » INORGANIC MERCJRY
N.ALL DATA 93
TRUE VAL. 3.40
MEAN,ALL 5.1309&
MEAN.3ET. 3.40088
MEDIAN 3.38000
RANGE 11.10000 COEF. VAR. 0.37856
VARIANCE 1.65755 SKEWNESS 2.31488
STD. DEV. 1.28746 NO. OF CELLS 9
CONF. LIM. + 2.53740 (95 PCTI
ACCURACY
0.02595 PCT RELATIVE ERROR
DATA IN ASCENDING ORDER
0.20
0.67
1.20
1.40
1.48
1.50
1.60
1.90
2.00
2.00
2.00
2.10
2.28
2.40
2.45
2.60
2.75
2.80
3.00
3.00
3.08
3.10
3.10
3.10
3.10
3.10
3.10
3.10
3.14
3.20
3.20
3.20
3.20
3.20
3.20
3.20
3.20
3.20
3.30
3.30
3.30
3.30
3.30
3.30
3.36
3.40
3.40
3.40
3.43
3.45
3.50
3.50
3.50
3.50
3.50
3.50
3.50
3.50
3.50
3.50
3.50
3.50
3.60
3.60
3.70
3.80
3.80
3.80
3.80
3.80
3.81
3.90
4.00
4.00
4.00
4.10
4.20
4.20
4.20
4.40
4.40
4.70
4.70
4.80
4.85
4.87
4.91
6.25
6.30
11.30
23.10R
28.00R
120.OOR
MIDPOINT FRE3. HISTOGRAM
RETAINED DATA ONLY
0.8167
2.0500
3.2833
i».5167
5.7500
6.9833
8.2167
9.4500
10.6833
12
55
16
2
0
0
0
1
XXXX
XXXXXXXXXXXX
xxxxxxxxxxxxxxx
xxxxxxxxxxxxxxx
XX
REJECTED DATA
16
-------
TABLE 9
Data Summary by Ampul, Analyses for
Total Mercury in Distilled Water
AMPUL 6 INCREMENT * 4.1 UG/LITER ORGANIC * INORGANIC MERCURY
MtALL DATA 92
TRUE VAL. 4.10
^FAN.ALL 6.23096
MEAN,RET. 4.25785
MEDIAN 4.20000
RAN3E 10.39999 COEF. VAR. 0.33264
VARIANCE 2.00610 SKEWNESS 0.83313
STO. DEV. 1.41636 NO. OF CELLS 9
CDNF. LIM. + 2.79163 (95 PCT)
ACCURACY
3.85005 PCT RELATIVE ERROR
DATA IN ASCENDING ORDER
0.20
0.90
1. 11
1.25
1.65
2.10
2.50
2.60
2.90
3.10
3.21
3.30
3.30
3.40
3.40
3.50
3.50
3.60
3.60
3.70
3.70
3.73
3.80
3.80
3.80
3.80
'3.80
3.90
3.90
4.00
4.00
4.00
4.00
4.10
4.10
4. 10
4. 10
4.10
4.10
4.10
4. 10
4.20
4.20
4.20
4.20
4.20
4.20
4.20
4.22
4.27
4.29
4.30
4.30
4.30
4.30
4.30
4.38
4.40
4.40
4.40
4.50
4.50
4.50
4.50
4.50
4.60
4.60
4.60
4.60
4.70
4.80
4.95
5.00
5.08
5.10
5.20
5.40
5.40
5.56
5.60
5.86
5.89
5.90
6.00
6.70
7.50
7.70
8.00
10.60
16.30R
30.00R
11*8. OCR
MIDPOINT FREO. HISTOGRAM
RETAINED DATA ONLY
7778
9333
0889
0.
1.
3.
i»,
S.itOOO
6.5556
7.7111
8.8667
10.0222
3
12
52
12
2
3
0
1
XXXX
XXX
xxxxxxxxxxxx
xxxxxxxxxxxxxxx
xxxxxxxxxxxx
XX
XXX
REJECTED DATA
17
-------
TABLE 10
Data Summary by Ampul, Analyses for
Total Mercury in Distilled Water
AMPUL 7 INCREMENT = 8.8 UG/LITE" ORGANIC + INORGANIC MERCURY
19.45000 COfcF. VAR.
6.78160 SKEWNESS
2.60415 NO. OF CELLS
•f 5.13338 (95 PCT)
NiALL DATA
TRUE VAL.
MEANtALL
MCANfRET.
MEDIAE
90
8.80
12.91*298
8.47665
8.70000
RANGE
VARIANCE
STD. OEV.
CONF. LIM.
0.30721
0.23553
9
ACCURACY -3.67439 PCT RELATIVE E*ROR
DATA IN ASCENDING OR-DFR
0.55
2.00
3.14
3.30
3.35
3.60
4.20
4.40
4.56
5.00
6.00
6.0C
6.20
6.30
6.80
6.85
7.00
7.20
7.30
7.40
7.43
7.50
7.50
7.70
7.80
7.90
8.00
8.00
8*00
8.10
8.?0
8.20
8.30
8.30
a.35
8.40
8.40
8.50
8.50
8.56
8.60
8.60
8.70
8.70
8.70
8.80
9.00
9.00
9.00
9.00
9.00
9.00
9.00
9.10
9.10
9.10
9.20
9.30
9.30
9.30
9.30
9.40
9.40
9.40
9.50
9.60
9.80
10.00
10.00
10.00
10.00
10.00
10.05
10.20
10.51
10.60
10.75
10.99
11.00
11.00
11.60
11.88
12.00
12.00
13.00
13.20
20.00
36.40R
63.00R
328.OOR
MIDPOINT FREO. HISTOGRAM
RETAINED DATA ONLY
1.6306
3.7917
5.9528
8.1139
10.2750
12.1*361
11*.5972
16.7583
18.9191*
2
7
8
39
2l»
6
0
0
1
XX
xxxxxxx
xxxxxxxx
xxxxxxxxxxxxxxx
xxxxxxxxxxxxxxx
xxxxxx
REJECTED DATA
18
-------
TABLE 11
Data Summary by Ampul, Analyses for
Total Mercury in Distilled Water
A«PUL 8 INCREMENT =• 9.6 UG/LITER ORGANIC + INORGANIC MERCURY
NfALL DATA 92
THUS VAL. 9.60
MtAN.ALL 1U.06519
MEAN,SET. 9.37776
MFOIAN 9.30000
VARIANCE
STO. DEV.
C3NF. LIM.
24.42000 COEF. VAR. 0.34549
10.49769 SKEWNESS 0.93523
3.24001 NO. OF CELLS 9
+ 6.35042 (95 PCT)
ACCURACY
-2.31498 PCT RELATIVE ERROR
DATA IN ASCENDING ORDER
0.58
1. 18
2.30
3.59
4.10
4.25
4.60
4.80
4.80
5.20
6.20
7.20
7.30
50
7.50
7.60
7.70
7.80
7.89
8.00
8.10
8.20
8.20
8.30
8.34
8.40
8.48
8. 80
8.80
8.80
8.90
8.90
9.00
9.00
9.00
9.00
9.00
9.10
9.10
9.10
9. 10
9.20
9.20
9.30
9.30
9.30
9.50
9.60
9.60
9.60
9.60
9.60
9.70
9.70
9.80
9.80
9.90
9.90
S.95
10.00
10.00
10.00
10.00
10.00
10.00
10.00
10.00
10.00
10.40
10.40
10.80
11.00
11.00
11.03
11.20
11.40
11.85
11.96
12.00
12.50
12.80
13.00
13.00
13.25
13.30
13.50
14.00
15.75
18.60
25.00
68.00R
382.OOR
MIDPOINT FREQ. HISTOGRAM
RETAINED DATA ONLY
1.9367
U.6500
7.3633
10.0767
12.7900
15.5033
18.2167
20.9300
23.61*33
3
7
17
1*9
11
1
1
0
1
XXX
xxxxxxx
xxxxxxxxxxxxxxx
xxxxxxxxxxxxxxx
xxxxxxxxxxx
X
X
= REJECTED DATA
19
-------
TABLE 12
Data Summary by Ampul, Analyses for
in Natural Water
AMPUL 1 INCREMENT = 0.21 UG/LITER ORGANIC + INORGANIC MERCURY
N.ALL DATA 78
TRUE VAL. 0.21
MEANtALL
MEAN,RET
MEDIAN
ACCURACY
0.51*21*3
0.34945
0.27000
66.40551
RANGE
VARIANCE
STD. DEV.
CONF. L1M.
1.27000
0.07598
0.27564
+0.54761
COEF. VAR.
SKEWNESS
NO. OF CELLS
(95 PCT)
0.78879
1.44675
PCT RELATIVE ERROR
DATA IN ASCENDING ORDER
0.00
0.00
0.00
0.00
0.03
0.07
0.08
0.10
0.10
0. 10
0.10
0.10
0.14
0.15
0.15
0.15
0.16
0.18
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.20
n.20
0.22
0.22
0.22
0.22
0.23
0.24
0.25
0.26
0.27
0.29
0.30
0.30
0.30
0.30
0.30
0.30
0.30
0.32
0.35
0.39
0.40
0.40
0.40
0.40
0.44
0.44
0.45
0.47
0.48
0.48
0.49
0.50
0.50
0.50
0.56
0.64
0.80
0.80
0.80
0.90
1.00
1.00
1.00
1.20
1.27
1.80R
2.20R
3.35R
i*.70R
U.75R
MIDPOINT FREQ. HISTOGRAM
RETAINED DATA ONLY
0.079U 16 XXXXXXXXXXXXXXX
0.2381 29 XXXXXXXXXXXXXXX
0.3969 11 XXXXXXXXXXX
0.5556 7 XXXXXXX
0.711*1* 1 X
0.8731 1* XXXX
1.0319 3 XXX
1.1906 2 XX
R = REJECTED DATA
20
-------
TABLE 13
Data Summary by Ampul, Analyses for
in Natural Water
AMPUL 2 I>JCRE*EMT = 0.27 UG/LITER DR&ANIC
INORGANIC MERCURY
N.ALL DATA 82 RAN3E
TRUE y/AL. 0.27 VARIANCE
,ALL 0.65390 STD. DEV.
0.41402 CONF. LIM.
0.32000
ACCURACY 53.34271 PC.T RELATIVE ERROR
1.20000 COEF. VAR. 0.67494
0.0780S SKEWNESS 1.06406
0.27944 NO. OF CELLS 9
±0.55477 (95 PCT)
DATA IN ASCENOIMS ORUER
MIDPOINT FREO. HISTOGRAM
RETAINED DATA ONLY
3.00
0.00
0.06
0.07
0.10
0. 10
0.11
0.15
0.15
0.16
0. 16
0.19
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.21
0,21
0.?3
0.24
0.24
0.25
0.25
0.26
0.26
0.27
0.27
0.28
0.30
0.30
0.30
0.30
0.30
0.31
0.31
0.32
0.32
0.33
0.35
0.35
0.35
0.35
0.40
0.4C
0.40
0.40
0.42
0.44
0.46
0.49
0.50
0.50
0.50
0.50
0.50
0.50
0.53
0.59
0.61
0.65
0.65
0.78
0.80
0.80
0.80
0.80
1.00
1.00
1.00
1.00
1.00
1.05
1.10
1.20
2.09R
2.60R
3.80R
5.75R
7.50R
0.0667 7 XXXXXXX
0.2000 21 XXXXXXXXXXXXXXX
0.3333 21 XXXXXXXXXXXXXXX
O.l»666 11 XXXXXXXXXXX
0.5999 U XXXX
0.7332 5 XXXXX
0.8665 0
0.9998 6 XXXXXX
1.1331 2 XX
* REJECTED DATA
21
-------
TABLE 14
Data Summary by Ampul, Analyses for
in Natural Water
3 l\CREMEMT = 0.51 UG/LITPR ORGANIC «• INORGANIC MERCURY
N.ALL DATA 85
TRUE VAL. 0.51
MCAM.ALL
MEDIAN
ACCURACY
1.11*505
0.67384
0.50500
RANGE
VARIANCE
STD. DEV.
CDNF. LIM.
3.99000
0.29254
0.54087
+1.08031
COEF. VAR.
SKEWNESS
NO. OF CELLS
(95 PCT)
0.80267
3.32568
9
32.12645 PCT RELATIVE ERROR
DATA IN ASCENDING ORDER
0.01
0.10
0.11
0.20
0.20
0.20
0.20
0.22
0.26
0.28
0.30
0.30
0.32
0.34
0.35
0.35
0.35
0.37
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.40
0.42
0.44
0.45
0.46
0.47
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.51
0.52
0.55
0.56
0.56
0.57
0.60
0.60
0.60
0.60
0.62
0.64
0.65
0.66
0.69
0.70
0.70
0.75
0.77
0.80
0.82
0.93
0.95
1.00
I. 00
1.00
1.05
1.06
1.10
1.10
1.10
1.20
1.40
1.40
1.44
1.46
1.70
2.40
4.00
4.20R
4.30R
7.50R
8.00R
18.U8R
MIDPOINT FREU. HISTOGRAM
RETAINED DATA ONLY
0. 2317
0.6750
1.1183
1.5717
2.0050
2.1*1(83
2.8917
3.3350
3.7783
30
30
11
5
0
1
0
0
1
xxxxxxxxxxxxxxx
xxxxxxxxxxxxxxx
xxxxxxxxxxx
xxxxx
REJECTED DATA
22
-------
TABLE 15
Data Summary by Ampul, Analyses for
in Natural Water
AMPUL 4 INCREMENT = 0.60 US/LITFR ORGANIC t INORGANIC MERCURY
M.ALL DATA 80
TRUE VAL. 0.60
Me AN,ALL
MEAN,RET.
MEDIAN
ACCURACY
0.70864
0.60000
18.10795
RANSE 2.30030 COEF. VAR. 0.55003
VARIANCE 0.15192 SKEWNESS 1.32462
STD. DEV. 0.38977 NO. OF CELLS 8
CONF. LIM. +0.77421 (95 PCT)
PCT RELATIVE ERROR
DATA IN ASCEMOIMS ORDER
0.00
0.10
0.16
0.20
0.22
0.25
0.30
3.30
0.35
3.35
0.38
0.40
0.40
0.40
0.44
0.45
0.46
0.46
0.49
0.49
0.50
0.50
0.50
0.50
0.50
0.50
0.50
3.50
0.53
3.55
0.56
0.58
0.60
0.60
3.60
0.60
0.60
0.60
0.61
0.62
0.64
0.64
0.65
0.66
0.69
0.70
0.72
0.72
0.73
0,
75
0.80
0.80
O.BO
0.90
0.91
0.95
0.96
1.00
.00
.00
.00
.00
.00
1.05
1.10
1.20
1.20
1.30
1.32
1.50
1.50
1.60
1. 70
2.30
2.66P
3.90R
4.20R
7.50R
8.70R
10.00R
MIDPOINT FREQ. HISTOGRAM
RETAINED DATA ONLY
0.11*38
O.U313
0.7188
.0063
.2938
.5813
.8688
2.1563
6
25
22
12
xxxxxx
xxxxxxxxxxxxxxx
xxxxxxxxxxxxxxx
xxxxxxxxxxxx
xxxx
xxxx
= REJECTED DATA
23
-------
TABLE 16
Data Summary by Ampul, Analyses for
in Natural Water
AMPUL 5 INCREMENT = 3.4 US/LITER ORGANIC + INORGANIC MERCURY
NtALL DATA 83
T*UE VAL. 3.40
ME AM,ALL 5.38288
MCAN.RET. 3.41149
RANGE 12.37000 COEF. VAK. 0.43743
VARI&NCE 2.22696 SKEWNESS 2.56669
STD. DEV. 1.49230 NO. OF CELLS 9
CONF. LIM. + 2.94313 195 PCT)
MEDIAN
ACCURACY
3.40500
0.33800 PCT RELATIVE ERROR
DATA IN ASCENDING ORDER
0.13
0.16
0.64
0.85
1.36
1.70
1.80
2.10
2.10
2.10
2.10
2.10
2.40
2.50
2.60
2.79
2.80
2.80
2.80
2.80
2.90
2.90
2.94
2.96
3.00
3.00
3.00
3.00
3.10
3.15
3.20
3.20
3.30
3.30
3.30
3.30
3.40
3.40
3.40
3.40
3.41
3.48
3.50
3.50
3.50
3.50
3.50
3.50
3.50
3.55
3.60
3.60
3.60
3.60
3.70
3.70
3.70
3.80
3.80
3.80
3.80
3.80
3.95
4.00
4.00
4.00
4.20
4.20
4.20
4.40
4.60
4.60
4.70
4.84
4.85
5.00
5.06
5.40
7.20
12.50
18.86R
30.00R
125.OCR
MIDPOINT FREQ. HISTOGRAM
RETAINED DATA ONLY
0.8172
2.1916
3.5661
l».9l»05
6.3150
7.6891*
9.0639
10.U383
11.8128
5
15
-------
TABLE 17
Data Summary by Ampul, Analyses for
in Natural Water
6 INCREMENT * 4.1 KG/LITE* ORGANIC
INORGANIC MERCURY
N.ALL DATA
TRUE VAL.
MFAN.ALL
MF AN, RET.
MFDIAM
80
4.10
6.lilt311
3.80854
4.00000
RANGE
VARIANCE
STD. DEV.
CDNF. LIM.
6.33000 COEF. VAR. 0.29282
1.24377 SKEWNESS -0.9S121
1.11524 NO. OF CELLS 8
+2.21445 (95 PCT)
ACCURACY
-7.10865 PCT RELATIVE ERROR
DftTA IN ASCENDING ORDER
0.17
0.77
0.83
1.10
1.70
1.70
2.20
2.30
2.50
2.70
2.70
3.00
3.00
3.10
3.10
3.?0
3.20
3.30
3.50
3.60
3.70
3.70
3.73
3.77
3.90
3.90
3.90
3.90
4.00
4.00
4.00
4.00
4.00
4.00
4.00
4.00
4.00
4.00
4. 10
4.10
4.10
4.10
4.10
4.20
4.20
4.20
4.22
4.25
4.30
4.30
4.30
4.30
4.30
4.40
4.40
4.50
4.50
4.50
4.50
4.58
4.60
4.70
4.80
4.80
4.95
5.00
5.00
5.00
5.20
5.60
5.60
5.82
6.50
19.00R
21.00R
33.00R
153.OOR
MIDPOINT FREQ. HISTOGRAM
RETAINED DATA ONLY
0.5657
1.3569
2.U82
2-939U
3.7307
"*-5219
5.3132
3 XXX
3 XXX
l» XXXX
9 XXXXXXXXX
27 XXXXXXXXXXXXXXX
21 XXXXXXXXXXXXXXX
7 XXXXXXX
2 XX
REJECTED DATA
25
-------
TABLE 18
Data Summary by Ampul, Analyses for
in Natural Water
AMPUL 7 INCREMENT = 8.8 UG/LITE" ORGANIC «• INORGANIC MERCURY
N.ALL DATA 80
TRUE VAL. 8.80
MLAN.ALL 13.62260
MEAN,*ET. 8.76676
MEDIAN 8.50000
RANGE 27.47000 COEF. VAR.
VARIANCE 13.65052 SKEWNESS
STD. DEV. 3.69466 NO. OF CELLS
CONF. LIW. + 7.24153 (95 PCT)
2.00048
8
ACCURACY
-0.37750 PCT RELATIVE E*ROR
DATA IN ASCENDING ORDER
0.53
1.88
2.45
3.00
3.22
3.42
3.90
4.50
4.80
6.10
6.30
6.'3 6
6.50
6.60
6.80
7.20
7.21
7.30
7.34
7.40
7.50
7.76
7.80
7.80
8.00
8.00
8.10
8.10
8.20
8.20
H.30
8.30
8.30
8.35
8.40
8.40
8.40
8.43
8.50
8.50
8.50
8.50
8.60
8.60
8.70
8.80
8.90
8.90
9.00
9.00
9.00
9.00
9.00
9.10
9. 10
9.40
9.45
9.50
9.70
9.80
10.05
10.30
10.40
10.60
10.70
11.00
11.00
11.03
11. ?0
11.98
12.00
12.00
13.00
13.00
13.80
15.75
21.30
28.00
66.00R
3UO.OOR
MIDPOINT FREQ. HISTOGRAM
RETAINED DATA ONLY
2.2U69 7 XXXXXXX
5.6807 12 XXXXXXXXXXXX
9.1UI* 1(6 XXXXXXXXXXXXXXX
12.5U82 10 XXXXXXXXXX
15.9819 1 X
19.U157 0
22.8U91* 1 X
26.2832 1 X
REJECTED DATA
26
-------
TABLE 19
Data Summary by Ampul, Analyses for
in Natural Water
RECOVERY OF INCREMENT FROM NATURAL WATER
AMPUL 8 INCREMENT * 9.6 UG/LITER ORGANIC * INORGANIC MERCURY
N.ALL DATA 79
TRUE VAL. 9.60
MEAN,ALL
MEAN,RET.
MEDIAN
1U.57516
9.09660
9.20000
RANGE 25.76000 COEF. VAR. 0.39210
VARIANCE 12.722*6 SKEWNESS 1.11538
STD. DEV. 3.56685 NO. OF CELLS 8
CONF. LIM. ± 6.99103 (95 PCT)
ACCURACY -5.24370 PCT RELATIVE ERROR
DATA IN ASCENDING ORDER
1.18
1.98
3.35
3.52
3.80
4.00
4.10
5.00
5.10
5.40
6.20
6.20
6.72
7.20
7.30
7.50
7.60
7.80
7.80
7.96
8.00
8.10
8.10
8.30
8.30
8.3*
8.50
8.70
8.80
8.90
9.00
9.00
9.00
9.00
9.05
9.10
9.10
9.20
9.20
9.20
9.40
9.40
9.50
9.50
9.50
9.60
9.60
9.60
9.70
9.80
9.80
9.80
9.95
10.00
10.00
10.00
10.00
10.50
10.70
10.70
10.80
11.00
11.00
11.80
11.80
11.98
12.00
12.00
12.60
12.80
13.27
14.00
14.50
15.40
17.00
26.30
72.00R
379.OOR
MIDPOINT FREQ. HISTOGRAM
RETAINED DATA ONLY
2.1500
5.3700
8.5900
11.8100
15.0300
18.2500
21.1*700
2l».6900
5
9
kk
lit
3
1
0
1
XXXXX
xxxxxxxxx
xxxxxxxxxxxxxxx
xxxxxxxxxxxxxx
XXX
X
R - REJECTED DATA
27
-------
Statistical Summaries
A statistical summary is given in Tables 20 and 21 for each sample.
Most of the statistics have been selected from Tables 4 through 19 to
allow a convenient comparison of the effect that differences in concen-
tration level and background water had on the retained data.
Single-Analyst Precision
In Tables 20 and 21, the standard deviations (S) indicate the dispersion
expected among values generated from a group of laboratories. This
represents the broad error in any mass of data collected in a collaborative
study. However, the measure of how well an individual analyst can expect
to perform in his own laboratory is another important measure of precision.
This single-analyst precision is measured here as the Sr value. It was
defined by Youden (2) as
where
n = the number of paired observations.
D = the difference between observation for a sample
pair.
D = the average value for D .
Youden's Sr calculation permits a measure of precision without
duplication and hopefully avoids the well-intentioned manipulation of
data that can occur in a laboratory doing replicate determinations.
Statements of Method Precision
Linear regressions were performed on the overall and single-analyst
precision estimates shown in Tables 20 and 21 for the cold vapor method
of determining mercury in distilled and natural waters. Plots of these
regressions are shown in Figures 1 and 2. Mathematical expressions of
the precision statements for mean recovery (X) from 0.2-10 yg/liter of
total mercury in distilled and natural waters are given as follows:
Distilled Water:
Overall precison (S) = 0.2454 + 0.2922 X
Single-analyst precision (Sr) = 0.3117 + 0.0718 X
28
-------
TABLE 20
STATISTICAL SUMMARY
Recovery of Total Mercury from Distilled and Natural Waters
STATISTICAL
PARAMETERS
True Value, yg/1
Mean Recovery, yg/1 (X)
Accuracy as %
Rel . Error
Standard Dev. , yg/1 (S)
Relative Dev. , %
Range, yg/1
Single-Analyst Standard
Dev., yg/1 (S )
Single-Analyst
Relative Dev. , %
DISTILLED WATER
SAMPLE 1 SAMPLE 2
.21 .27
.418 .450
98.9 66.5
.279 .325
66.9 72.2
1 . 60 1 . 80
0.19
44
NATURAL WATER
SAMPLE 1 SAMPLE 2
.21 .27
.349 .414
66.4 53.3
.276 .279
78.9 67.5
1.27 1.20
0.16
42
DISTILLED WATER
SAMPLE 3 SAMPLE 4
.51 .60
.653 .744
28.1 24.0
.376 .466
57.5 62.6
2.26 2.97
0.36
51
NATURAL WATER
SAMPLE 3 SAMPLE 4
.51 .60
.674 .709
32.1 18.1
.541 .390
80.3 55.5
3.99 2.30
0.16
23
-------
TABLE 21
STATISTICAL SUMMARY
Recovery of Total Mercury from Distilled and Natural Waters
U)
O
STATISTICAL
PARAMETERS
True Value, pg/1
Mean Recovery, ug/1 (X)
Accuracy as %
Rel. Error
Standard Dev. , ug/1 (S)
Relative Dev. , %
Range, ug/1
Single-Analyst Standard
Dev., ug/1 (Sr)
Single-Analyst
Relative Dev. , %
DISTILLED WATER
SAMPLE 5 SAMPLE 6
3.4 4.1
3.40 4.26
0.03 3.85
1.29 1.42
37.9 33.2
11.1 10.4
0.79
20
NATURAL WATER
SAMPLE 5 SAMPLE 6
3.4 4.1
3.41 3.81
0.34 -7.11
1.49 1.12
43.7 29.3
12.4 6.3
0.36
10
DISTILLED WATER
SAMPLE 7 SAMPLE 8
8.8 9.6
8.48 9.38
-3.7 -2.3
2.60 3.24
30.7 34.5
19.4 24.4
0.89
10
NATURAL WATER
SAMPLE 7 SAMPLE 8
8.8 9.6
8.77 9.10
-0.4 -5.2
3.69 3.57
42.1 39.2
27.5 25.8
1.39
16
-------
Y AXIS
•••4
l-l
Q) .|.
o
M
e
c
o
•H
CO
•H
O
<1)
FIGURE 1
Linear Regression Plot of Precision in Distilled Water
The precision of this method for total mercury in
distilled water samples, within the recovery range
of 0.2-10 yg/liter, may be expressed as follows:
S = 0.2454 + 0.2922 X
Sr - 0.3117 + 0.0718 X
...-••••••'
Mean Recovery (X), yg mercury/liter
31
-------
Y AXIS
+4
• S
M
-------
Natural Water:
Overall precision (S) = 0.1661 + 0.3647 X
Single-analyst precision (Sr) = 0.0465 + 0.1379 X
Statements of Method Accuracy
Linear regressions were performed on the mean recovery estimates
shown in Tables 20 and 21 for the cold vapor method of determining
mercury in distilled and natural waters. Plots of these regressions are
shown in Figures 3 and 4. Mathematical expressions of the mean recovery
for 0.2-10 yg/liter of total mercury in distilled and natural waters are
given as follows:
Distilled Water;
Mean Recovery, X - 0.2028 + 0.9517 (True Concentration)
Natural Water:
Mean Recovery, X = 0.1373 + 0.9508 (True Concentration)
Two-Sample (Youden) Charts
The retained data were plotted according to the method of Youden and
are shown in Figures 5 through 12. Two results for each sample pair were
used respectively as the x and y coordinates to plot a single point for
each analyst. The plot of points for each sample pair shows the perform-
ance of the method for that concentration level.
If random errors were largely responsible for the spread of results
around the true values, the data on a plot would be equally distributed
among the four quadrants (+ +), (- +), (- -) and (+ -). However, if
systematic error influences the method more, the values are not randomly
distributed but are grouped along a 45° slope line in the (- -) and (+ +)
quadrants. This occurs because an analyst tends to get either high or
low results on both samples in a pair, forming an elliptical pattern on a
45° slope. If an analyst shows large systematic or random error relative
to other data, his plot points will be far removed from the general
cluster. Extreme values suggest a procedure or instrument out of control.
If the method of analysis is inherently imprecise there will be a general
scatter of data points away from the 45° line. A significant bias or
interference in the method will cause the general grouping to be low (- -)
or high (+ +).
The presence of a number of values greater than the true values
crowded the plots of points which were less than the true values. In
order to present these points more fairly, scale units for the plots were
selected which would place the true value at least one-third of the
33
-------
distance from the origin. This arbitrary rule worked well on all data
plots, presenting a reasonable spread of data points over each chart and
providing an interpretablfe representation of method performance. Data
which were extremely high are shown as greater than (>) values in the
upper right-hand corner of each plot.
34
-------
Y AXIS
o
M
I
*
M
SI
O
o
0)
d "•2
FIGURE 3
Linear Regression Plot of Accuracy in Distilled Water
Accuracy as the mean recovery of this method for
total mercury in distilled water samples, within
the true concentration range of 0.2-10 vg/liter,
may be expressed as follows:
Mean Recovery - 0.2028 + 0.9517 (True Concentration)
2 4 6 8 X AXIS
True Concentration, yg of mercury/liter
35
-------
FIGURE 4
Linear Regression Plot of Accuracy in Natural Water
Accuracy as the mean recovery of this method for
total mercury in natural water samples, within
the true concentration range of 0.2-10 yg/liter,
may be expressed as follows:
Mean Recovery = 0.1373 + 0.9508 (True Concentration)
Y AXIS
M
0)
3
o
)-l
01
o
60
01
o
o
0)
Pi
d
ca
0)
S
4 4 4- 4-
2 4 6 8 X AXIS
True Concentration, yg of mercury/liter
36
-------
FIGURE 5
Two Sample Chart for Recovery of Total Mercury, vg/liter
0-6
0-5.
0-4 .
0-3
0-2
0-1
0-0
0
xxxx (>0,6)
. . . vy . XXX
cu
u
3 x
(
X
X
X^^
^^ Y
' ^^v^ ^^
^^ ^^
\^^ ^
X
DISTILLED WATER -
X XX X
/\
x x x
xx x
x x x B
; x
x *\ x
o ^
x xx
X XX
X
X
SAMPLE 1
• O 0-1 0-2 0-3 0-4 0«5 0
-6
37
-------
FIGURE 6
Two Sample Chart for Recovery of Total Mercury, yg/liter
XXXXX (>0,6)
XXXXX
0-5 .
0-4 .
0-3.
i
t
0-2.
0-1 .
*
4
0-0
1 -1-
X
ru
LJ
i X
fl
X
X X
: x x
X
X >< x *
x x
x x
X
M 1 »-
NATURAL WATER
x
x x xx
X
X
X
X X
XX X
x x* X -
xx x
£ x
X
x x
xx
X
SAMPLE 1
•M 1 1 I
0-1 0-2 0-3 0-4 0-5 0-6
38
-------
FIGURE 7
Two Sample Chart for Recovery of Total Mercury, yg/liter
XXXXX (>1,2)
i-2
1-0 .
0-8
Q'B
0-4
0-2 .
0-0
T
LJ
X XX
X X
X X
X
X x xx
X
1 1 ,
DISTILLED WATER x
X
x xx
XX X
x x
X
xx x x x
xxx
/XX X
x x
<
<
X
SAMPLE 3
' 1 1 1
0-0 O-2 0-4 0-6 0-8 1-0 1-2
39
-------
FIGURE 8
Two Sample Chart for Recovery of Total Mercury, pg/liter
1-2
1-0 .
O-Q .
O-G
0-4.
0-2 .
0-0
O
xxxx (>1,2)
. . . . . xxx ...
X
-vr
Ld
S x
^
X>
x X X V
X *
V
X XX >
x xx
XXX
X X
X X
X
X
X
X
NATURAL WATER
X
X
XX X
x X
x x
X X
X3 x
' ^ x
X
X
X
SAMPLE 3
-O O-2 0-4 O-G O-8 1-0 1-2
40
-------
FIGURE 9
Two Sample Chart for Recovery of Total Mercury, vg/liter
B-0
6-O
4-O
2-0
0-0
ID
vx
><
x
x
X
•+-H-
DISTILLED WATER
x x *
x x x
X
XX
SAMPLE 5
O«O 2-O 4-0 G-O
8-0
41
-------
FIGURE 10
Two Sample Chart for Recovery of Total Mercury, vg/liter
8-0
6-0 ..
4-0.
2-G.
0-0
ID
+
NATURAL WATER
x x
X
X X X
x xx
* x
X*XX
v
8 X
XX
X
x x
0-0
2-0
SAMPLE 5
4-0
6-0
8-0
42
-------
FIGURE 11
Two Sample Chart for Recovery of Total Mercury, yg/liter
x (>20)
20-0
16- Q
12- Q
8-0 .
4-0 .
O-O
CD
X
X
X '
X* $
x *xx
X
*«*
X
X
X
X
1 1 —
DISTILLED WATER
X
X
X x xX
Xxx X
xxx
xxX5x
X
gpx x
n ^V
X
SAMPLE 7
i j — _ 1
0-0
4-0
8-0
12-O 16-0 20-0
43
-------
FIGURE 12
Two Sample Chart for Recovery of Total Mercury, ng/liter
20
xx (>20)
4-0
)-C
;-c
CD
U
Itf
I
1 x
3
X $
„*£
3
'X~
X
XX
xx
xXxX
X
X
X
NATURAL WATER
X
X
X
X
X X
< *
x x
\£\C v V
*'*\s^\ X\
f - —
XX
X
•
SAMPLE 7
0-0 4-Q 8-0 12-0 16-0 20
-------
DISCUSSION AND CONCLUSIONS
Throughout the 0.2-10 vg/liter concentration range tested, mercury
was detected and measured using the cold vapor procedure of Kopp (1).
In describing method performance, it has been common to assume that
statistics such as mean recovery (X), standard deviation (S) and single-
analyst standard deviation (Sr) are: 1) constants which are independent
of the true concentration level or 2) uniform percentages of the true
concentration. Tables 20 and 21 show that neither of these assumptions
is valid within the concentration range studied. As a matter of fact,
for most studies, whenever the concentration range approaches the detection
limit these assumptions seem to be invalid. An alternative is to assume
that some linear relationship exist between the statistics and the true
concentration level. If this is true, then regression equations of the
form Y = aX + b will provide good predictions of the method statistics.
Please note that the earlier two assumptions are really special cases of
the linear assumption.
In this study, the regression equation plots in Figures 1 through 4
fit the points well enough to justify a linear assumption and should,
therefore, prove useful for predicting the statistics of this method
within the 0.2-10 yg/liter range studied.
Another interesting observation that can be made from Tables 20 and
21 and Figures 1 through 4 is that the type of background water did not
have any dramatic effect upon the method statistics. This indicates that
the method is not sensitive to natural interferences. However, since few
analysts used marine waters or industrial effluents, this conclusion is
limited to natural surface waters such as rivers and lakes.
Visual interpretation of the Youden plots (Figures 5-12) leads to a
better understanding of the method precision and bias statistics in
Tables 20 and 21 and Figures 1 through 4. First notice that the points
tend to approach the hypothetical 45 degree line as the concentration
level increases. This indicates less relative influence attributable to
random error and thereby verifies the decreasing single-analyst relative
deviation. Next, note that the points generally tend to form a denser
cluster as the concentration level increases. This verifies the decreasing
relative deviation values presented in Tables 20 and 21. Also, note that
points away from the intersection of the true concentration lines tend to
be high for the lower two concentration levels (0.2-0.6 yg/liter) and low
for the higher two concentration levels (3-10 yg/liter). This verifies
the decreasing percent relative error values in Tables 20 and 21.
45
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In conclusion, the vigorous digestion procedure using permanganate,
persulfate and heat as specified in the method, successfully reduces the
organic mercury to a measurable form.
The precision and accuracy of the method for distilled water and
natural water samples follows:
Distilled Water;
Precision S - 0.2454 + 0.2922 X
Sr - 0.3117 + 0.0718 X
Accuracy
Mean Recovery, X •= 0.2028 + 0.9517 (cone)
Natural Water;
Precision S - 0.1661 + 0.3647 x"
Sr = 0.0465 + 0.1379 X
Accuracy
Mean Recovery, X = 0.1373 + 0.9508 (cone)
REFERENCES
1. Kopp, J. F., M. C. Longbottom and L. B. Lobring, 1972. Cold
Vapor Method for the Determination of Mercury, J A W W A, Vol.
64, No. 1, pp. 20-25.
2. Youden, W. J., 1967. Statistical Technique for Collaborative
Tests, Association of Official Analytical Chemists, Inc., Wash-
ington, D.C.
46
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APPENDIX
Proposed Standard Method of Test for Total Mercury in Water (1)
1.
1.1 This method describes a procedure for the determination of
total mercury in water in the range of 0.2-10.0 yg Hg/liter. It consists
of a wet chemical oxidation which converts all mercury to the mercuric
ion; reduction of mercuric ions to metallic mercury, followed by a cold
vapor atomic absorption (AA) Analysis (2, 3).
1.2 The method is applicable to fresh waters, saline waters, and
industrial and sewage effluents.
1.3 Both organic and inorganic mercury compounds may be analyzed by
this procedure if they are first converted to mercuric ions. Potassium
permanganate in acid solution oxidizes some organomercury compounds but
studies have shown that several methyl and phenyl mercury compounds are
only partially oxidized by this method. However, using potassium persulfate
and potassium permanganate as oxidants, and a digestion temperature of 95
C, approximately 100% recovery of these compounds can be obtained (3, 4).
1.4 The range of the method may be varied through instrument and/or
recorder expansion and by using a larger volume of sample.
1.5 A method for the disposal of mercury containing wastes is also
presented (Appendix Al).
2. Summary of Method
2.1 The cold vapor AA procedure is a physical method based on the
absorption of ultraviolet radiation at a wavelength of 253.7 nm by mercury
vapor. The mercury is reduced to the elemental state and aerated from
solution in either a closed recirculating system or an open one-pass
system. The mercury vapor passes through a cell positioned in the light
path of an atomic absorption spectrophotometer. Absorbance is measured
as a function of mercury concentration.
3. Significance
3.1 The cold vapor AA measurement portion of this method is applicable
to the analysis of materials other than water (sediments, biological
materials, tissues, etc.) if, and only if, an initial procedure for
digesting and oxidizing the sample is carried out, insuring that the
mercury in the sample is converted to the mercuric ion, and is dissolved
in aqueous media (3, 6).
47
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4. Definitions
4.1 For definitions of terms used in this method, refer to ASTM
Definitions D1129, Terms Relating to Water (7).
5. Interference
5.1 Possible interference from sulfide is eliminated by the addition
of potassium permanganate. Concentrations as high as 20 mg/liter of
sulfide as sodium sulfide do not interfere with the recovery of added
inorganic mercury from distilled water (3). •
5.2 Copper has also been reported to interfere; however, copper
concentrations as high as 10 mg/liter had no effect on the recovery of
mercury from spiked samples (3).
5.3 Sea waters, brines and industrial effluents high in chlorides
require additional permanganate (as much as 25 ml). During the oxidation
step, chlorides are converted .to free chlorine which will also absorb
radiation at 253.7 nm. Care must be taken to assure that free chlorine
is absent before the mercury is reduced and swept into the cell. This
may be accomplished by using an excess of hydroxylamine sulfate reagent
(25 ml). In addition, the dead air space in the reaction flask must be
purged before the addition of stannous sulfate. Both inorganic and
organic mercury spikes have been quantitatively recovered from sea water
using this technique.
5.4 Interference from certain volatile organic materials which will
absorb at this wavelength is also possible. If this is expected, the
sample should be analyzed both by using the regular procedure and again
under oxidizing conditions only, that is, without the stannous sulfate.
The true mercury value can then be obtained by subtracting the two values.
6. Apparatus
6.1 See Figure 1 for the schematic of the closed recirculating
system and Figure 2 for the open one-pass system.
6.2 Atomic Absorption Spectrophotometer - Any commercial atomic
absorption instrument is suitable if it has an open burner head area in
which to mount an absorption cell, and if it provides the sensitivity and
stability for the analyses. Also instruments designed specifically for
the measurement of mercury using the cold vapor technique in the working
range specified are commercially available and may be substituted.
6.3 Mercury Hollow Cathode Lamp
6.4 Recorder - Any multi-range variable speed recorder that is
compatible with the UV detection system is suitable.
48
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6.5 Absorption Cell - See Figure 3 - The cell is constructed from
glass or plexiglass tubing 25.4 mm O.D. x 114 mm (Note 1). The ends are
ground perpendicular to the longitudinal axis and quartz window (25.4 mm
diameter x 1.6 mm thickness) are cemented in place. Gas inlet and outlet
ports (6.4 mm diameter) are attached approximately 12 mm from each end.
The cell is strapped to a support and aligned in the light beam to give
maximum transmittance.
Note 1 - An all glass absorption cell, 18 mm O.D. by 200 mm, with
inlet 12 mm from the end, 18 mm O.D. outlet in the center, and
with quartz windows has been found suitable.
6.6 Air Pump - Any peristaltic pump, with electronic speed control,
capable of delivering 1 liter of air per minute may be used. (Regulated
compressed air can be used in an open one-pass system).
6.7 Flowmeter - Any flowmeter capable of measuring an air flow of 1
liter per minute is suitable.
6.8 Aeration Tubing - A straight glass frit having a coarse porosity
is used in the reaction flask. A clear flexible vinyl plastic tubing
such as Tygon, is used for passage of the mercury vapor from the reaction
flask to the absorption cell.
6.9 Drying Tube - 150 mm x 18 mm diameter tube containing 20 grams
of magnesium perchlorate. A small reading lamp with 60w bulb may also be
used to prevent condensation of moisture inside the cell. The lamp is
positioned to shine on the absorption cell maintaining the air temperature
in the cell about 10 C above ambient.
6.10 Reaction Flask - Either a 300 ml B.O.D. bottle or 250 ml
erlenmeyer flask fitted with a rubber stopper may be used.
7. Reagents
7.1 Purity of Reagents - Reagent grade chemicals, or equivalent, as
defined in ASTM Methods E 200, for Preparation, Standardization, and
Storage of Standard Solutions for Chemical Analysis (7), shall be used in
this test.
7.2 Purity of Water - Unless otherwise indicated, references to
water shall be understood to mean reagent water conforming to ASTM
Specification D1193, for Reagent Water, Type I (7).
7.3 Mercury Standard Solutions
7.3.1 Mercury, Stock Standard Solution (1 ml « 1 mg Kg) - Dissolve
0.1354 grams of mercuric chloride (HgCl2) in 75 ml of distilled water
containing 10 ml of concentrated nitric acid and dilute to 100 ml in a
volumetric flask.
49
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7.3.2 Mercury, Intermediate Standard Solution (1 ml = 10 yg Hg) -
Add 10 ml of the stock mercury solution to distilled water containing 2
ml of concentrated nitric acid and dilute to 1 liter. Prepare fresh
daily.
7.3.3 Mercury Working Standard Solution (1 ml = 0.1 yg Hg) - Add 10
ml of the intermediate mercury standard to distilled water containing 2
ml of concentrated nitric acid and dilute to 1 liter. Prepare fresh
daily.
7.4 Nitric Acid (Sp gr 1.42) - Concentrated nitric acid (HNO-j) ,
reagent grade.
Note 2 - If a high reagent blank is obtained, the reagent grade
HN03 will have to be distilled or a spectro-grade acid will have
to be used.
7.5 Potassium Permanganate Solution (50 g/liter) - Dissolve 50
grams of potassium permanganate (KMnO^) in distilled water and dilute to
one liter.
7.6 Potassium Persulfate Solution (50 g/liter) - Dissolve 50 grains
of potassium persulfate (K2S20g) in distilled water and dilute to one
liter.
7.7 Sodium Chloride - Hydroxylamine Sulfate Solution (120 g/liter) -
Dissolve 120 grams of sodium chloride (NaCl) and 120 grams of hydroxylamine
sulfate [(NH2OH)2H2S04] in distilled water and dilute to one liter.
7.8 Stannous Sulfate Solution (100 g/liter) - Dissolve 100 grams of
stannous sulfate (SnSO^) in distilled water containing 14 ml of concen-
trated sulfuric acid and dilute to one liter. This mixture is a suspension
and should be stirred continously during use.
7.9 Sulfuric Acid (Sp gr 1.84) - Concentrated sulfuric acid O^SO^) ,
reagent grade.
8. Sampling
8.1 Collect the samples in accordance with the applicable method of
American Society for Testing and Materials, as follows:
D510 - Sampling Industrial Water (7)
D860 - Sampling Water from Boilers (7)
D1496 - Sampling Homogenous Industrial Waste Water (7)
8.2 Samples should be collected in acid-washed glass or high density
polyethylene bottles. Samples could be analyzed within 38 days if collected
in glass bottles, and within 13 days if collected in polyethylene bottles
(8).
50
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8.3 Samples should be preserved with concentrated nitric acid to a
pH of 2 or less immediately at the time of collection, normally about 2
ml/liter. If only dissolved mercury is to be determined, the sample
should be filtered through a 0.45 jj membrane filter using an all glass
filtering apparatus before acidification.
9. Calibration
9.1 Transfer 0, 1.0, 2.0, 5.0 and 10.0 ml aliquots of the working
mercury solution containing 0-1.0 yg of mercury to a series of reaction
flasks. Add enough distilled water to each flask to make a total volume
of 100 ml. Mix thoroughly and add 5 ml of concentrated sulfuric acid and
2.5 ml of nitric acid to each flask (Note 3).
Add 15 ml of KMnO^ solution to each bottle and allow to stand at
least 15 minutes. Add 8 ml of potassium persulfate to each flask and
heat for two hours in a water bath at 95 C. Cool to room temperature and
add 6 ml of sodium chloride—hydroxylamine sulfate solution to reduce the
excess permanganate. After waiting 30 seconds treat each flask individ-
ually by adding 5 ml of the stannous sulfate solution and immediately
attach the bottle to the aeration apparatus forming a closed system.
Continue as described under Procedure (10.1).
Note 3 - Loss of mercury may occur at elevated temperatures.
However, with the stated amounts of acid the temperature rise
is only about 13 C. (25-38 C) and no losses of mercury will
occur (3).
10. Procedure
10.1 Transfer 100 ml or an aliquot diluted to 100 ml containing not
more than 1.0 yg of mercury to a reaction flask. Add 5 ml of sulfuric
acid and 2.5 ml of nitric acid mixing after each addition (Note 3, 9.1).
Add 15 ml of potassium permanganate solution to each sample bottle.
Shake and add additional portions of potassium permanganate solution
until the purple color persists for at least 15 minutes. Add 8 ml of
potassium persulfate to each flask and heat for 2 hours in a water bath
at 95 C. Cool and add 6 ml of sodium chloride-hydroxylamine sulfate to
reduce the excess permanganate. Wait 30 seconds and add 5 ml of stannous
sulfate to each flask individually and immediately attach it to the
aeration apparatus. The circulating pump, which has previously been
adjusted to a rate of 1 liter per minute, is allowed to run continuously.
The absorbance will increase and reach maximum within 30 seconds.
As soon as the recorder pen levels off, approximately 1 minute, open the
by-pass valve and continue the aeration until the absorbance returns to
its minimum value (Note 4). Close the by-pass valve, remove the stopper
and frit from the reaction flask and continue the aeration. Proceed with
the standards and construct a standard curve by plotting peak height
versus micrograms of mercury.
51
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Note 4 - Because of the toxic nature of mercury vapor, precaution
must be take to avoid its inhalation. Therefore, a by-pass has been
included in the system to either vent the mercury vapor into an exhaust
hood or pass the vapor through some absorbing media, such as:
(a) equal volumes of 0.1N KMnO^ and 10% t^SO^
(b) 0.25% iodine in 3% KI solution
11. Calculation
11.1 Determine the peak height of the unknown from the chart and
read the mercury value from the standard curve.
11.2 Calculate mercury concentration in sample by formula:
yg Hg/liter pg Hg X 10°0
in aliquot volume of aliquot
12. Precision and Accuracy
12.1 A statement of precision and accuracy will be made available by
the:
Quality Assurance Branch
Environmental Monitoring and Support Laboratory,EPA
Cineinnati, Ohio
52
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APPENDIX REFERENCES
1. These methods are under the jurisdiction of ASTM Committee D-19 on
Water. Annual Book of ASTM Standards, Part 31, Water. American
Society for Testing and Materials, Philadelphia, PA.
2. Hatch, W. R. and W. L. Ott, 1968. Determination of Sub-Microgram
Quantities of Mercury by Atomic Absorption Spectrophotometry, Anal.
Chem. 4(3:2085.
3. Kopp, J. F., M. C. Longbottom and L. B. Lobring, 1972. Cold Vapor
Method for Determining Mercury, JAWWA 64:20.
4. U.S. Environmental Protection Agency. Mercury Recovery Study,
Region IV Surveillance and Analysis Division, Athens, Georgia.
(Not Published)
5. Dean, Robert B., Robert T. Williams and Robert H. Wise, 1971.
Disposal of Mercury Wastes from Water Laboratories, Environmental
Science and Technology, 5^:1044.
6. Uthe, J. F., F. A. J. Armstrong and M. P. Stainton, 1970. Mercury
Determination in Fish Samples by Wet Digestion and Flameless Atomic
Absorption Spectrophotometry, Jour. Fisheries Research Board of
Canada, 27:805.
7. Appears in this publication.
8. U.S. Environmental Protection Agency. Mercury Perservation Study,
Region IV Surveillance and Analysis Division, Athens, Georgia.
(Not Published)
53
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SCHEMATIC ARRANGEMENT OF EQUIPMENT FOR MERCURY MEASUREMENT
by Cold Vapor AA Technique
Closed Recirculating System
FIGURE 1
A - Reaction Flask
B - Drying Tube, filled with
C - Rotameter, 1 liter of air/minute
D - Absorption Cell with quartz windows
E - Air Pump, 1 liter of air/minute
F - Glass tube with fritted end
G - Hollow cathode mercury lamp
H - AA Detector
J - Gas washing bottle containing 0.25% iodine in a 3% potassium iodine solution
K - Recorder, any compatible model
54
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SCHEMATIC ARRANGEMENT OF EQUIPMENT FOR MERCURY MEASUREMENT
by Cold Vapor AA Technique
Open One-Pass System
FIGURE 2
A
u
V
IE
A - Reaction Flask
B - Drying Tube, filled with MgC104
C - Rotameter, 1 liter of air/minute
D - Absorption Cell with quartz windows
E - Compressed Air, 1 liter of air/minute
F - Glass tube with fritted end
G - Hollow cathode mercury lamp
H - AA Detector
J - Vent to hood
K - Recorder, any compatible model
L - To vacuum through gas washing bottle contain 0.25% iodine in a 3%
potassium iodine solution
55
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FIGURE 3
10 -18 CM
CELL FOR MERCURY MEASUREMENT
BY COLD VAPOR TECHNIQUE
The length and OD of the cell are not critical. The body of the cell
may be of any tubular material but the end windows must be of quartz because
of the need for UV transparency.
The length and diameter of the inlet and outlet tubes are not important,
but the position of the side arms may be a factor in eliminating recorder
noise. There is some evidence that displacement of the air inlet arm away
from the end of the cell results in smoother readings. A mild pressure in
the cell can be tolerated, but too much pressure may cause the glued-on end
windows to pop off.
Cells of this type may be purchased from various supply houses.
56
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APPENDIX
Al. Disposal of Mercury Containing Wastes
Al.l Introduction
Mercury salts are components of the wastes from the following
determinations:
Chemical Oxygen Demand, D1252
Ammonia in Water, D1426
Chloride Ion in Industrial Water and Wastewater, D512
Examination of Water Formed Deposits by Chemical Microscopy,
D1245
Also, mercuric chloride is often used to preserve water samples for
nitrogen and phosphorus analysis.
The safest way to retain mercury salts is as the sulfide at a high
pH. Acidic solutions should be neutralized and combined with alkaline
wastes and water samples containing mercury preservatives. To precipitate
mercury, a convenient source of the sulfide ion is sodium thiosulfate.
However, it should not be added to acidified wastes because of its rapid
decomposition to elemental sulfur. The sulfur which precipitates in-
creases the volume of sludge which must be processed and stored.
Mercury sulfide is insoluble and is stable to most reagents except
aqua regia and bromine. Bacterial conversions to methyl mercury are pre-
vented by maintaining the pH above 10.
A1.2 Procedure
Dilute all combined acidic wastes to about twice their original
volume. Adjust the pH to greater than 7 by slowly adding sodium hydroxide
solution (40-50 percent, w/v) with stirring. Combine this neutralized
waste and any pooled alkaline wastes with stirring. At this point the
combined wastes should have a pH of 10 or higher; if not, add sodium
hydroxide until a pH of 10-11 has been obtained.
While the combined alkaline wastes are still warm, stir in small
portions of sodium thiosulfate solution (40-50 percent, w/v) until no
further precipitation seems to occur. Allow the precipitate to settle.
Draw off a few milliliters of clear supernatant, make sure the pH
is still above 10, and then add an equal volume of sodium thiosulfate
solution. If the supernatant still contains dissolved mercury, a pre-
cipitate will rapidly form, indicating that additional sodium thiosulfate
must be added to the waste slurry.
57
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After the precipitate has settled, decant or siphon off the clear
tested supernatant and discard it. Wash the precipitate twice with
water containing a trace of NaOH, allow to settle, and discard both of
the clear washings. Dry the washed precipitate first in air, then in an
oven at a temperature no higher than 110 C.
Store the dry solids until a sufficient quantity has accumulated to
justify shipment to a commercial reprocessor: (Table 1).
Metallic mercury and waste organomercurials should be stored in
suitable air tight containers until a commercial reprocessor can be
contacted for specific shipping instructions: (Table 1).
58
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TABLE 1
Reprocessors of Mercury (a)
Bethlehem Apparatus Co., Inc. M
Front and Depot Streets
Hellertown, PA 18055
Phone: (215) 838-703A
Goldsmith Division, National Lead Co. M
111 North Wabash
Chicago, IL 60602
Phone: (312) 726-0232
Mallinckrodt Chemical Works MCO
223 West Side Avenue
Jersey City, NJ 07303
Phone: (201) 432-2500
(Mr. Frank L. Mackey, Western Branch Plant Manager)
Quicksilver Products, Inc. MC
350 Brannan Street
San Francisco, CA 94107
Phone: (415) 781-1988
(Miss Grace Emmans, Owner and President)
Sonoma Mines, Inc. C
P.O. Box 226
Guerneville, CA 95446
Phone: (707) 869-2013
Wood Ridge Chemical Corp. MC
Park Place East
Wood-Ridge, NJ 07075
Phone: (201) 939-4600
(Mr. E. L. Cadmus, Technical Director)
M = Supplies flask for return of metallic mercury.
C = Will accept mercury sulfide for reprocessing.
0 = Will accept certain organic mercury chemicals.
Note a - Special approval must always be obtained before shipment
is made to a reprocessor.
59
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GLOSSARY OF TERMS
The statistical measurements used in method study reports of the
Environmental Monitoring and Support Laboratory-Cincinnati are defined
as follows:
Accuracy as % Relative Error (Bias) . The signed difference between
mean value and the true value, expressed as a percent of the true
value.
R. E. , % = y - X 100
Atrue
Confidence Limit (95%) . The range of values within which a single
analysis will be included, 95% of the time.
95% C. L. = X ± 1.96S
Mean Recovery. The arithmetic mean of reported values; the average.
Median. Middle value of all data ranked in ascending order. If
there are two middle values, the mean of these values.
n. The number values (X^ reported for a sample.
Range. The difference between the lowest and highest values reported
for a sample.
Relative Deviation (Coefficient of Variation). The ratio of_the
standard deviation, S, of a set of numbers to their mean, X,
expressed as percent. It is an attempt to relate deviation
(precision) of a set of data to the size of the numbers so that
deviations at different mean values can be compared.
R. D. - 100 =
X
Skewness (k). A pure number, positive or negative, which indicates
the lack of symmetry in a distribution. For example, "k is positive
if the distribution tails to the right and negative if the distri-
bution tails to the left.
Z(X, - X)3
60
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Standard Deviation (S). The most widely used measure to describe
the dispersion of^ a set of data. Normally, X ± S will include
68 percent, and X ± 2S will include about 95 percent of the
data from a study.
n - 1
Standard Deviation: Single Analyst (Sr). A measure of dispersion
for data from a single analyst. Calculated here using an
equation developed by Youden based on his non-replicate study
design.
t test. The difference between a single observation (Xn) and the
estimated population mean (X) expressed as a ratio over the
estimated population standard deviation (S) . The value obtained
is compared with critical values from a table for the Student's
t distribution. If the calculated t value exceeds the theoretical
t value at a prescribed confidence level, the analyzed value is
probably not from the same population as the rest of the data and
can be rejected.
61
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TECHNICAL REPORT DATA
(Please react Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/4-77-012
3. RECIPIENT'S ACCESSIOr+NO.
4. TITLE ANDSUBTITLE
EPA Method Study 8, Total Mercury in Water
5. REPORT DATE
February 1977 issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
John Winter, Paul Britton, Harold Clements
and Robert Kroner
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Environmental Monitoring and Support Laboratory-Cin,,(
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
10. PROGRAM ELEMENT NO.
[ 1HD621
11. CONTRACT/GRANT NO.
P.O. No. 5-03-4294
12. SPONSORING AGENCY NAME AND ADDRESS
Same as above.
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA/600/06
15. SUPPLEMENTARY NOTES
Prepared in part under contract, P.O. No. 5-03-4294 by Robert C. Kroner.
16. ABSTRACT " ~
The Environmental Monitoring and Support Laboratory-Cincinnati of EPA
conducts EPA's quality assurance program for the water laboratories and
assists EPA laboratories in the choice of methods for physical, chemical,
biological and microbiological analyses. The responsibility for quality
assurance activities of EMSL is assigned to the Quality Assurance Branch
(QAB). This study, one of the QAB activities, describes a joint EPA/ASTM
evaluation study of a method of analysis for total mercury in natural water
and wastewaters. The method includes an acid-permanganate-persulfate digestion
followed by reduction and measurement of mercury in the vapor phase at
253.7 nm. This report describes the study, its conclusions and provides
statements of precision and accuracy.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Mercury Inorganic Compounds
Mercury Organic Compounds
Water Analysis
Waste Disposal
Industrial Wastes
Method Validation Studies
Statistical Evaluation
Analysis for ug/liter
levels of mercury
07/B
07/C
8. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (ThisReport)
21. NO. OF PAGES
76
20. SECURITY CLASS (This page)
22. PRICE
EPA Form 2220-1 (9-73)
62 vV U.S. GOVtHMMEHT MIKTING OFFICE 1977-757-056/55'(9 Region No. 5-11
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