METHOD STUDY 2
NUTRIENT ANALYSES, MANUAL METHODS
1970
ENVIRONMENTAL PROTECTION AGENCY
Water Quality Office
Analytical Quality Control Laboratory
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METHOD STUDY 2, NUTRIENT ANALYSES,
MANUAL METHODS
An Evaluation of Analytical Methods for Water and Wastewater
1970
ENVIRONMENTAL PROTECTION AGENCY
Water Quality Office
Analytical Quality Control Laboratory
1014 Broadway
-------
METHOD STUDY 2, NUTRIENT ANALYSES,
MANUAL METHODS
An Evaluation of Analytical Methods for Water and Wastewater
J. A. Winter and M. R. Midgett
ENVIRONMENTAL PROTECTION AGENCY
Water Quality Office
Analytical Quality Control Laboratory
1014 Broadway
Cincinnati, Ohio 45202
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Table of Contents
Page
ACKNOWLEDGEMENTS Hi
PARTICIPATING LABORATORIES iv
SUMMARY V
INTRODUCTION 1
DESCRIPTION OF THE STUDY 2
Test Design 2
Preparation of Samples and Reporting of Results 2
True Values 3
Analytical Methods 4
Glossary of Terms 5
RESULTS 7
Raw Data 7
TREATMENT OF DATA 8
Statistical Summary 8
Rejection of Outliers 9
Two-Sample Charts 9
DISCUSSION AND CONCLUSIONS 10
Ammonia Nitrogen 10
Nitrate Nitrogen 17
Orthophosphate 24
Kjeldahl Nitrogen 31
Total Phosphorus 38
Characterization of Natural Waters 45
Interferences from Natural Waters 46
REFERENCES 47
APPENDIX 1 - Tabulation of Data 48
APPENDIX 2 - Summary of Data, Recoveries from Distilled Water 54
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ACKNOWLEDGEMENTS
The authors acknowledge the technical assistance and guidance
of Mr. Elmo C. Julian, Analytical Quality Control Laboratory, in the
design, development and operation of the statistical and graphical
computer programs used in this study.
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PARTICIPATING LABORATORIES
Forty-nine analysts in twenty-two laboratories took part in Method
Study 2j Nutrients. Of these, three were non-Water Quality Office (WQO)
laboratories. The participating laboratories were:
WQO Laboratories
Alaska Water Laboratory
College, Alaska
California/Nevada Basins
Sub-Region
Alameda, California
Chesapeake Technical Support
Laboratory
Annapolis, Maryland
Colorado River/Bonneville
Services Branch
Salt Lake City, Utah
Division of Field Investi-
gations
Cincinnati, Ohio
Hudson-Delaware Basins Office
Edison, New Jersey
Joint WQO-DC Pilot Plant
Washington, D.C.
Lake Huron Basin Office
Grosse lie, Michigan
Lake Michigan Basin Office
Chicago, Illinois
Lake Ontario Basin Office
Rochester, New York
Lower Ohio Basin Office
Evansville, Indiana
New England Basin Office
Needham Heights, Massachusetts
Missouri Basin Laboratory
Kansas City, Missouri
Pacific Northwest Water Laboratory
Corvallis, Oregon
R. S. Kerr Water Research Center
(Technical Programs)
Ada, Oklahoma
R. S. Kerr Water Research Center
(Research Program)
Ada, Oklahoma
Shagawa Lake Eutrophication Control
Pilot Project
Ely, Minnesota
Southeast Water Laboratory
Athens, Georgia
Upper Ohio Basin Office
Wheeling, West Virginia
Non-WQO Laboratories
Solid Wastes Office, EPA
Cincinnati, Ohio
California Division of Water
Resources Regional Laboratory
San Bernardino, California
Washington Pollution Control
Commission
Olympia, Washington
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METHOD STUDY 2, NUTRIENT ANALYSES, MANUAL METHODS
An Evaluation of Analytical Methods for Water and Wastewater
SUMMARY
The Analytical Quality Control Laboratory of the Water Quality Office,
EPA, formerly Federal Water Quality Administration, conducted interlabora-
tory studies on selected chemical methods of analysis for ammonia nitrogen,
nitrate nitrogen, Kjeldahl nitrogen or organic nitrogen, orthophosphate
and total phosphorus. Samples were prepared in pairs at similar yet
different concentrations for each constituent. Analysts added an aliquot
of each concentrate to distilled water and to a natural water of their
choice. Single analyses were made on the distilled and natural water
samples with and without added increments. Recoveries were compared and
the bias of the method, the interference of natural water samples and the
relative precision of each analyst and laboratory were determined. On
pages vi and vii a statistical summary of this data shows the precision
and accuracy values which may be expected in routine work.
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A Statistical Summary of Method Study 2,
Nutrient Analyses, Manual Methods
Ammonia Nitrogen Analyses
of Natural Water Samples
True Value, mg N/1 iter
.26
.21
1.71
1.92
Mean of Recoveries by
Difference,mg N/liter
.21
.22
1.75
1.96
Accuracy as % Relative
Error (Bias)
-18.12
-5.54
.46
-2.01
Standard Deviation,
mg N/liter
.07
.12
.24
.28
Range, mg N/liter
.30
.63
1.01
1.17
Nitrate Nitrogen Analyses of Natural Water Samples
True Value, mg N/liter
.16
.19
1.24
1.08
Mean of Recoveries by
Difference, mg N/liter
.16
.20
1.25
1.16
Accuracy as % Relative
Error (Bias)
-6.79
8.30
2.82
4.12
Standard Deviation,
mg N/liter
.09
.08
.21
.24
Range, mg N/liter
.46
.33
1.01
1.44
Orthophosphate Phosphorus Analyses of Natural Water Samples
True Value, mg P/liter
.029
.038
.383
.335
Mean of Recoveries by
Difference - mg P/liter
.027
.036
.374
.326
Accuracy as % Relative
Error (Bias)
-4.95
-6.00
-1.76
-2.75
Standard Deviation,
mg P/liter
.010
.008
.023
.018
Range, mg P/liter
.046
.036
.126
.071
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Statistical Summary, Contd.
Kjeldahl Nitrogen
- Organic Nitrogen Analyses of Natural
Water Samples
True Value, mg N/liter
.31
.20
4.10
4.61
Mean of Recoveries by
Difference, mg N/liter
.33
.23
4.14
4.53
Accuracy as % Relative
Error (Bias)
5.45
15.54
1.03
-1.67
Standard Deviation,
mg N/liter
.25
.20
1.06
1.19
Range, mg N/liter
1.05
.77
3.97
4.71
Total Phosphorus
Analyses of Natural Water Samples
True Value, mg N/liter
.110
.132
.882
.772
Mean of Recoveries by
Difference, mg P/liter
.121
.155
.890
.813
Accuracy as % Relative
Error (Bias)
3.09
11.99
.92
2.96
Standard Deviation,
mg P/liter
.033
.051
.129
.130
Range, mg P/liter
.167
.318
.765
.777
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1
METHOD STUDY 2, NUTRIENT ANALYSES, MANUAL METHODS
An Evaluation of Analytical Methods for Water and Wastewater
INTRODUCTION
The Water Quality Office, EPA, formerly Federal Water Quality
Administration, gathers water quality data to determine compliance with
water quality standards, to provide information for planning of water
resources development, 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.
To insure the reliability of physical, chemical, biological and
microbiology data, the Division of Water Quality Research established the
Analytical Quality Control (AQC) Laboratory, at 1014 Broadway, Cincinnati,
Ohio. The AQC program, conducted by this laboratory, is designed to assure
the reliability, and when necessary, the legal defensibility of all water
quality information collected by the Water Quality Office.
The Method and Performance Evaluation (M§PE) Activity of the AQC
Laboratory conducts evaluative interlaboratory studies of analytical pro-
cedures selected for use in WQO. In this study the nutrient parameters
were examined to obtain the accuracy and precision of the selected manual
methods used in the participating WQO laboratories. The evaluation of
results also permits a judgment of the relative capabilities of these
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2
DESCRIPTION OF THE STUDY
Test Design
Youden's non-replicate technique of x and y samples (1) is used in
a test design as follows:
1. Each sample is prepared as a stable concentrate in a sealed
glass ampul.
2. As many sample constituents as possible are combined in a
single ampul.
3. Using Youden's x-y sample technique, similar yet different
samples are prepared and analyzed once only.
4. When an aliquot of the concentrate is diluted to volume, all
constituents are present at levels found in natural waters.
5. Several levels of concentration are tested to cover the normal
levels found in surface waters.
6. Each of the x-y sample pair is added independently to a
distilled water and natural water of choice and samples
analyzed. The distilled and natural waters are analyzed
with and without increments.
Recoveries are compared.
Preparation of Samples and Reporting of Results
Eight water sample concentrates were prepared for Method Study 2
by dissolving weighed amounts of reagent-grade chemicals in ASTM
reagent-grade distilled water to produce accurately-known concentrations
of ammonia, nitrate, total Kjeldahl nitrogen, orthophosphate and total
phosphorus.
The distilled water, natural water spike technique was used in this
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3
of each concentrate to one liter with ammonia-free distilled water and
a river, lake, or estuarine water. For each constituent, a result was
obtained for: [1) the distilled + increment, (2) the natural water, and
(3) the natural water + increment. Recovery of the increment in natural
water was determined by difference.
The concentrates were preserved to prevent biological activity, and
were checked for stability by repeated analyses over a period of three
months. These analyses established that the solutions were stable, and
verified the concentration of each constituent. Further confirmation
of the true values was obtained from determinations by an independent
referee laboratory. The true values are shown in Table 1.
Table 1
True Values for Parameters*
When diluted in distilled water according to instructions, the water
samples contained the following concentrations of constituents, mg/1:
Ampul
nh3-n
N03-N
PO4-P
Kjeldahl-N
Total P
1
0.26
0.16
0.029
--
--
2
0.21
0.19
0.038
--
--
3
1.71
1.24
0.383
--
--
4
1.92
1.08
0.335
--
--
5
--
--
--
0.31
0.110
6
--
--
--
0.20
0.132
7
--
--
4.10
0.882
8
--
--
4.61
0.772
*The concentrations given in Table 1 are the actual levels present.
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4
Since dilution of the concentrates renders the preservative
ineffective, it was necessary to analyze the ammonia and orthophosphate
separately so that their values could not be increased by changes in the
form of total Kjeldahl nitrogen or total phosphorus. Therefore, ampuls
1 thru 4 contained solutions for the ammonia, nitrate, and orthophosphate
determinations while ampuls 5 thru 8 contained solutions for the total
Kjeldahl nitrogen and total phosphorus analyses.
The set of eight ampuls covered two ranges of concentration for
each measured parameter. Within each range, samples were paired, with
each member of a pair: 1 $ 2, 3 § 4, 5 § 6, and 7 5 8 being closely
related in concentration.
The sample concentrates were shipped to participating laboratories
on July 1, 1969. Detailed instructions for analyses and reporting of
results were provided at that time.
Analytical Methods
The analyses were performed according to the FWPCA Official Interim
Methods for Chemical Analysis of Surface Waters, September 1968 (2). The
methods used for these manual analyses are as follows:
Parameter
Ammonia
Nitrogen
Method
Distillation
Nitrate
Nitrogen
Modified
Brucine
Sulfate
Basic Reference
Standard Methods for the Exami-
nation of Water and Wastewater,
12th ed., APHA, Inc., N. Y.,
1965, 187-193.
Book of ASTM Standards, Part 23,
1967, Industrial Water; Atmos-
pheric Analysis, pp. 336-338.
Standard Methods for the Exami-
nation of Water and Wastewater,
12th ed., APHA, Inc., N. Y.,
1965, 198-200.
Book of ASTM Standards, Part 23,
1967, Industrial Water; Atmos-
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5
Kjeldahl
Nitrogen
Orthophosphate
Digestion
Total
Phosphorus
Single
reagent
PeTsulfate
digestion and
single reagent
method
Standard Methods for the Exami-
nation of Water and Wastewater,
12th ed., APHA, Inc., N. Y. ,
1965, 402-404.
Murphy, J. and Riley, J. P.,
"A Modified Single Solution
Method for the Determination
of Phosphate in Natural Waters,"
Anal. Chim. Acta, Vol. 27,
1962, pp. 31-36.
Gales, M. E., Jr., Julian, E. C.,
and Kroner, R. C., "Method for
Quantitative Determination of
Total Phosphorus in Water,"
JAWWA, Vol. 58, No. 10, 1966,
pp. 1363-1368.
Murphy, J. and Riley, J. P.,
"A Modified Single Solution
Method for the Determination
of Phosphate in Natural Waters,"
Anal. Chim. Acta3 Vol. 27, 1962,
pp. 31-36.
Glossary of Terms
The statistical measurements used in this report 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.
X - X
true
true
x 100
Confidence Limit (95%). The range of values within which a single analysis
will be included, 95% of the time.
X ± t
V~n~
Mean. The arithmetic mean of reported values, the average.
EX
n
Median. Middle value of all data ranked in ascending order,
two middle values, the mean of these values.
If there are
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6
Range. The difference in mg/1 between lowest and highest reported values.
Relative Deviation (Coefficient of Variation]. Thejratio of the standard
deviation, a, 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 between levels of values can be
compared.
100 -2-
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 distribution tails
to the left.
L (X. -X)3
3
no
Standard (a) Deviation. The most widely used measure of dispersion of a
set of data. It is equal to the square root of the variance and indicates
the deviation of 68% of the values around the mean, and 2.58a, the devia-
tion of 99.7% of the values around the mean, a, the standard deviation,
is the measure of the deviation of the universe. However, in most experi-
mental work with limited sampling and in this study only an estimated
standard deviation (s) is measurable. This differs in calculation in
that n-1 rather than n is used as the denominator. In this study and in
further studies, s and s2 not 0 ancj 02 wni be used to measure deviation
of the data. They will be referred to as the standard deviation and
variance respectively.
/ r xj - (i x.)2
V
t-test. The difference in analyzed and true value expressed as ratio over
the standard deviation. The value obtained is compared with critical
values in a table. If the calculated t-value exceeds the theoretical
t-value, the analyzed value is probably not from the same population as
the rest of the data and can be rejected.
^n - true value
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7
2 2
Variance (o ), (s ). The average of the squares of the deviations of a
group of numbers from their average, X.
2 2
p x.)
i iJ
2 n
a =
n
2
s =
2 2
E X - (I X.)
l v l
n
iT^l
RESULTS
Raw Data
A direct copy of the computer printout of all test results reported
by participant laboratories using manual methods is shown in Appendix 1
by parameter and by type of water sample. For the distilled water samples
a simple listing is given of laboratories and analysts with their reported
values. For the natural water samples, values were received for each analyst,
but because spiking 995 ml of natural water with 5 ml of sample concentrate
causes a 0.5% dilution change, the reported values were reduced by this
amount. Differences between the natural sample values and the corrected
(natural samples + spike) resulted in the corrected recovery values for
natural water samples in the text and in Appendix 1. These corrected
recovery values were used in all evaluations of data from natural waters.
For ease in computer calculations and to avoid premature round-off errors,
four digits were carried through all recovery calculations in the natural
waters. Only two or three significant figures should be used for all final
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8
TREATMENT OF DATA
Statistical Summary
A complete statistical summary is given in pages 12 thru 43. Each
parameter is discussed in turn with data displayed in two-sample charts
followed by statistical evaluations of the data for each concentration.
A program described by Larsen (3) was modified for an IBM 1130
computer and measurement of accuracy and presentation of ranked data
were added. This summary presentation named COLST provides all of
the statistical measurements necessary for evaluation of the data as
a direct copy of the computer printout. With the exception of accuracy,
all measurements: number of values, tr>ue value, mean, median, accuracy,
range, variance, standard deviation, 95% confidence limit, relative
deviation (coefficient of variation), and skewness are based on all data
received, without rejection. Accuracy, is based on retained data, that is
the data remaining after rejection of outliers using the t-test at the
99% level, because the inclusion of questionable extreme values will
result in unreasonable values for accuracy. In addition to the statistical
measurements, all data are ranked in ascending order and presented in a
histogram, using a six cell division. Each X in the histogram represents
one analytical result while the distribution of all X values characterizes
the method as used on these natural water samples.
The precision and accuracy of WQO methods are derived from natural
water data. For clarity and understanding, only the statistical summaries
of the natural water data are given in the text with the two-sample charts
for each parameter. The corresponding statistical summaries of the distilled
water data are given in Appendix 2. Comparisons of the two-sample charts
for natural and distilled water samples will indicate any major differences
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9
Rejection of Outliers
To determine the accuracy of each method, it was necessary to remove
those extreme values which had only a small chance of validity and which
would make a significant change in the accuracy measure. These values
were probably caused by gross instrumental, chemical or human error.
These extreme values were rejected by applying the two-tail t-test to
all values at a 99% probability level; that is, with a 99 to 1 assurance
that the data rejected were invalid and should be rejected. The data
points rejected by laboratory and analyst are indicated with a capital
letter, "R", after the values in Appendix 1. A greater spread of data
around the true value causes rejection of fewer outliers. As the pre-
cision term in the denominator of the t-test increases for a method the
calculated t value grows smaller and there are fewer extreme values
rejected as outliers. An example of this is the Kjeldahl nitrogen test
where no outliers were rejected because of the general imprecision of
much of the data. Contrariwise, with better accuracy and precision, the
t-test is more powerful and more outliers are rejected. An example is the
total phosphorus method where one or more values were rejected for each
sample tested. However, those data rejected in either case are true out-
liers and laboratories should carefully review procedures for the cause of
inaccuracy.
Two-Sample Charts
To effectively describe the recovery values obtained for each parameter
a series of two-sample charts, Figures 1 through 5, were prepared, as
suggested by Youden (1). All results were plotted by parameter and by water
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10
similar samples (152), (3§4), (5$6), and (7§8) are the coordinates on the
x and y axes that determined a single point for each analyst. The distri-
bution of points (analysts) characterizes the method-results for that sample.
If random errors were responsible for the spread of results around the
true values, then the data from the sample pair would be equally distributed
among the four quadrants (++) (-+) (--) (+-). However, systematic error
influences the data plots most and the distribution of values is not random
but on a 45° slope line in the (--) and (++) quadrants, since an analyst
getting a high or low value on one sample also gets a high or low value on
the similar sample. This distribution of values on a 45° slope forms an
elliptical pattern. Data points far removed from the elliptical cluster
indicate large systematic error for one analyst compared to the other
analysts. As random error decreases, data points move closer to the 45°
slope. Extreme values or outliers suggest a procedure or instrument out
of control. General scatter of data points away from the 45° line indicates
poor precision in the method. When all data are spread far out along the
45° line, a large systematic error is indicated for the method. When pre-
cision is satisfactory but a significant bias or interference occurs the
data grouping is low (--) or high (++) as in Figure 1.
DISCUSSION AND CONCLUSIONS
Ammonia Nitrogen-Distillation Method
0.21 - 0.26 mg N/liter, Ammonia Nitrogen
The manual distillation method of analyses for ammonia nitrogen showed
a high and variable bias (-18 to + 5%) at ammonia nitrogen levels of 0.21 to
0.26 mg/liter. The bias was directionally negative with 3 of 4 showing >5%
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11
sample (distilled and natural). The significant level of bias suggests
a variable and incomplete recovery of ammonia in the distillation. This
inaccuracy was compounded by standard deviations that were 32 - 56% of
the levels tested, indicating further the problems in ammonia analysis
at <1 mg/liter levels. At the .21 - .26 mg/liter level of ammonia
nitrogen, results from natural water samples can be expected to deviate
.14 - .24 mg/liter from mean values with a 95% probability.
1.71 - 1.92 mg N/liter, Ammonia Nitrogen
At the 2 mg/liter level, ammonia nitrogen showed good agreement
between values. Standard deviations were 10 - 14% of the levels tested.
Bias was reduced to 1 - 3%. Apparently, the lesser accuracy at 0.2 mg/liter
was related directly to the low levels of ammonia (<1 mg/liter) rather than
to the method itself.
Recoveries and precision measurements for ammonia were similar for the
distilled and natural water sample indicating no interference by sample
type. At the 1.7 - 1.9 mg/liter level of ammonia nitrogen results from
natural water samples will deviate 0.49 - 0.56 mg/liter from mean values
with a 95% probability.
Summary - Ammonia Nitrogen Analyses
In Figures 1A - ID, most results group near the true values with a
scattering of a few values some distance from the true values. The problems
in the ammonia distillation are inherent in the materials, method, or
technique used by a few analysts. However, the greater degree of scattering
of values with the low level samples suggests that it is very difficult to
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12
FIGURE 1 A-D
TWO SAMPLE CHARTS FOR AMMONIA NITROGEN, mg N/liter
.60
.50
.40
.30
.20
i i r
1 1 1 ¦ r -t - r ¦
1A
DISTILLED WATER
-
«SI
0
UJ
-as
-
^
¦
i i i
SAMPLE 1
. _L_ ,1 1 .1 . I.I
.70
.56
.42
.28
.14
0.10 .20 .30 .40 .50 .60
¦ r i * * i
r i ¦ -| r- "i -r ¦
1B
-
NATURAL WATER '
-
-
_
t
1 n#
_ _
LkJ
X
(/)
1 1 1
SAMPLE 1
i i i i i i
1 .14
28 .42 .56 .70
2.70
2.46
2.22
1.98
1.74
1.50
1
1
1 1 T W 1 1" 1
1C
DISTILLED WATER -
CO
. .
-
SAMPLE 3
¦ i i i i i i
2.80
2.52
2.24
1.96
1.68
i r
_l L
"I 1 1 1^ r-
ID
NATURAL WATER
J L
SAMPLE 3
J L
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MbTHOU AND PERFORMANCt EVALUATION, AQCL, WQO
METHOD STUDY 2, NUTRIENTS
13
NITROGEN - AMMONIA, AMPUL 1
STATISTICS, ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY OF INCREMENT FRCM NATURAL WATER
INCREMENT = 0.26
0.32888
0.42922
6
N
TRUE VAL.
MEAN
MEDIAN
ACCURACY
24
0.26
0.21289
0.22017
-18.11864
RANGE
VARIANCE
STD. OEV.
CONF LIM (95%)
0.30035
0.00490
0.07001
0. 13722
COEF. VAR.
SKEWNESS
NO. GF CELLS
PERCENT, RELATIVE TO TRUE VALUE.
RECOVERY OF INCREMENT
DATA IN
ASCENDING
OROER
0.0903
0.1206
0.1300
0.1337
0.1475
0.1600
0.1602
0.1602
0.1705
0.2001
0.2003
0.2102
0.2301
0.2303
0.2401
0.2401
0.2403
0.2470
0.2507
0.2703
0.2802
0.2906
0.3150
0.3906
HISTOGRAM
CELL MID.
0.0903
0.1503
0.2104
0.2705
0.3305
0.3906
FREQ.
L
8
8
5
I
1
xxxxxxxx
xxxxxxxx
xxxxx
x
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14
MbTHOC AND PERFORMANCE EVALUATION, ACCL, WQO
METHOD STUDY 2, NUTRIENTS
NITROGEN - AMMONIA, AMPUL 2
STATISTICS, ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY OF INCREMENT FRCM NATURAL WATER
INCREMENT = 0.21
N
TRUE VAL.
MEAN
MEDIAN
ACCURACY
24
0.21
0.21664
0.20022
-5.539^0
RANGE
VARIANCE
STD. DEV.
CONF LIM. (95%)
0.62640
0.01478
0.12157
0.23828
COEF. VAR.
SKEWNESS
NG. OF CELLS
PERCENT, RELATIVE TO TRUE VALUE.
0.56118
1.68018
6
RECOVERY OF INCREMENT
DATA IN
ASCENDING
ORDER
0.0106
0.0505
0.1337
0.14C2
0.1402
0.1500
0.1701
0.1703 HISTOGRAM
0.1801
0. 1803 CELL MIC. FREO.
0. 19C2
0.2001 C.0106 2 XX
0.2003 C.1358 9 XXXXXXXXX
0.2102 0.2611 10 XXXXXXXXXX
0.21C7 0.3864 ? XX
0.2201 0.5117 0
0.2203 0.6369 1 X
0 . 2 ?06
0.2475
C .
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METhOC ANC PERFORMANCE EVALUATION, ACCL, WQO
METHOD STUDY 2, NUTRIENTS
NITROGEN - AMMONIA, AMPUL 3
STATISTICS, ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY OF INCREMENT FRCM NATURAL WATER
INCREMENT = 1.71
N
TRUE VAL.
MEAN
MEDIAN
ACCURACY
24
1.71
I 74872
I.6853C
0. 46367
RANGE
VAR IANCE
STC. CEV.
CONF LIM. (95%)
1.01200
0.05970
0.24435
0.47893
COEF. VAR.
SKEWNESS
NC. OF CELLS
PERCENT, RELATIVE TC TRUE VALUE,
0. 13973
1.48382
6
RECOVERY OF INCREMENT
DATA IN
ASCENDING
OROER
1.4449
1.4801
1.5403
1.5701
1.6000
1.6102
1.6201
1.6302
1.6503
1.6603
1.6637
1.6803
1.6903
1.6975
1.7100
1.7102
1.7107
1.7302
1.7406
1.9206
2.1000
2.1406
2.2105
2.4570 R
HISTOGRAM
CELL MID.
1.4449
1.6473
1.8497
2.0521
2.2545
2.4569
FREQ.
3 XXX
16 XXXXXXXXXXXXXXXX
1 X
2 XX
1 X
1 X
-------
16
MlThOI. ANC PFRFORCANCE EVALOA f ION, ACCL, WQO
METHOD STUDY 2, NUTRIENTS
NITROGEN - AMMONIA, AMPUL 4
STATISTICS, ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY OF INCREMENT FRCM NATURAL kATER
INCREMENT = 1.92
0. 14267
216463
6
N 24 RANGE 1.17200
TKUt VAL. 1.92 VARIANCE 0.07783
MEAN 1.95539 STC. LEV. 0.27898
MEDIAN 1.86200 CONF. LIM. (95%) 0.5^680
ACCURACY -2.00814 PERCtNT, RELATIVE TO TRUE VALUE.
COEF. VAR.
SKEWNESS
NO. OF CELLS
RtCUVERY OF INCREMENT
DATA lis,
ASCENDING
ORDER
1 .6349
1.7 fC 1
1.8003
1.c102
1.8202
1.8 3C1
1.8302
1.83C3
1.84C0
1.84C1
1.8602
1 .8603
1.8637
l.fl/Ci
1.87C6
1 . 87C7
1. 8803
1 .9475
1.9505
1 .9 902
2. 16C0
2.2604
2. 73C6
2 . 8 C 7 C R
H I STGbRAM
CELL MU.
1 .6349
1.8694
2.1038
2.3382
2.5725
?.f>069
FREO.
I
18
L
1
0
2
xxxxxxxxxxxxxxxxxx
XX
X
X X
-------
17
Nitrate Nitrogen - Brucine Sulfate Method
0.16 - 0.19 mg/liter Level, Nitrate Nitrogen
The modified brucine sulfate method for nitrate nitrogen exhibited a
strong negative bias at the fractional mg/liter level for 3 of 4 distilled
and natural water samples. However, at these fractional mg/liter levels
this negative bias is only .02 mg/liter actual difference from true value
and may be acceptable. The bias and imprecision in samples containing
less than 1 mg/liter of nitrate nitrogen are clearly shown in Figures 2A
and 2B. Results from a natural water sample containing 0.16 - 0.19 mg/liter
level of nitrate nitrogen will deviate .16 - .18 mg N/liter from mean
values with a 95% probability.
1.08 - 1.24 mg/liter Level, Nitrate Nitrogen
There is a consistent positive bias at the 1 mg/liter level. With
samples containing 1.08 - 1.24 mg nitrogen per liter, the standard devia-
tions were 17 - 21% of the levels tested in natural waters. In Figures
2C and 2D, the results are tightly clumped around the true values showing
improved accuracy and precision at levels above 1 mg/liter. Results from
a natural water containing 1 - 1.2 mg nitrate nitrogen will deviate 0.43 -
0.49 mg N/liter from mean values with a 95% probability.
Summary - Nitrate Nitrogen Analyses
The modified brucine sulfate method for nitrate nitrogen has limited
accuracy and precision at .1 - .2 mg/liter levels. The limited precision
and accuracy are directly related to the level analyzed. When 1 - 2 mg
N/liter is present, the brucine sulfate method shows a reduced bias and
somewhat improved precision of .21 - .24 mg/liter.
The brucine method for nitrate is relatively simple and straight-
-------
18
The heating step is critical and must be carefully controlled if the method
is to be applied successfully. When a rack of tubes is immersed in the
boiling water bath, there is a sudden temperature drop with a lag of several
minutes before boiling begins again. This cooling varies with location of
the tubes in the bath, and with the location of the tubes relative to location
in the rack. The result is unequal color development and a corresponding
loss in reproducibility.
Problems in the heating and color development can be alleviated somewhat
by selection of a suitable water bath. The bath should have a tight-fitting
cover, preferably with a gable configuration, it should be of sufficient
depth that the tubes can be covered during the heating operation, and it
should have a circulating or stirring mechanism to maintain a uniform
-------
19
FIGURE 2 A-D
TWO SAMPLE CHARTS FOR NITRATE NITROGEN, mg N/liter
38
.32
.20
14
0.08
1 1
1 I 1 1 1 1 1
-
2A
DISTILLED WATER
_ CSI
LU
CO
1
"
-
1 1
SAMPLE 1
i i i i i i j
0.08 14
.20 .26 32 38
50
40
30
.20
.10
0.0
1 1 !
1 I I 1 1 1
2B
_
NATURAL WATER
-
-
-
CN
LU
-
2
, *
*
»
-
¦ i i
SAMPLE 1
I 1 1 1 I 1
0.0 10
.20 .30 .40 50
1 r
«
J !_1_
t 1 1 1 1 1 r
2C
DISTILLED WATER
V.
SAMPLE 3
¦ ' L
J I L
0.90 1.14 1.38 1.62 1.86 2.10
2.0
1.6
1.2
0.4
0.0
iiiiti
I
* <
i ,i i
2D
ATURAL WATER
t
~
-
_CL.
CO
SAMPLE 3
i i i
0 0 0.4 0.8 1.2
-------
20
MfclhCC AND PERFCRN ANCl: EVALUATICN, ACCL, WQO
METHOD STUDY 2, NUTRIENTS
NITROGEN - NITRATE, A^PUL 1
STATISTICS, ALL CATA, ALL LABCRATCRIES
MANUAL PROCEDURE
RECOVERY OF INCREMENT FRCP' NATURAL ^ATER
INCREMENT = 0.16
0. 56708
1.94475
6
\ 27 XANGE 0.45829
T,(Ut VAL. 0.16 VARIANCE 0.00852
ML AN 0. 16281 STC. LEV. 0.09232
MEDIAN 0.15015 CCNF. LIM. (95%) 0.18095
ACCURACY -6.79206 PERCENT, RELATIVE TO TRUE VALUE.
CCEF. VAR.
SKEWNESS
NO. CF CELLS
MtCi.VtRY OF INC.-lENEKT
DATA IN
A SCENLING
ORDER
O.CbC 2
0.0bC 3
0 . C 5 2 1
C . C b' C 1
0.U9 11
C.10C4
0.1010
0. 1 IC2
0.1120
C. 14C0
0. 14C2
0. 14
C. 15C 1
0. 15C I
0. 15C7
0 . 11: 1 C
0.17CB
0. 17CF
C. 1721
C. L / b 6
L.2060
C.2135
0.2 156
0 . 2 3 e 5
0.2454
C.295C
0 - 5 (J fc 5 R
H I STC:GRAM
CtLL MD.
C.C502
U . I 4 1 8
C.2335
C . J c 5 1
0 . 4 Uj b
0.5t 85
Fii EC.
b
15
5
1
0
1
xxxxx
xxxxxxxxxxxxxxx
xxxxx
x
-------
ME rHl)C AND PERFORMANCE: EVALUATIIN, ACCL, WQO
METHOD STUDY 2, NlfRIENTS
21
NI ri\OGbN - NITRATE, Ai*PUL 2
STATISTICS, ALL DATA, ALL LABORATORIES
MANUAL PRCCtCLRP
RECOVERY OF INCREMENT FRCM NATURAL WATER
INCREMENT = C.19
N 27 RANGE 0.32999
TRUE VAL. 0.19 VARIANCE 0.00683
Mt AN 0.20577 STC. CEV. 0.08264
MtC IAN 0.1938C CONF. LIM. C95%)0.l6l97
ACCURACY 8.30405 PERCENT, RfcLATIVE TO TRUE VALUE.
CCEF . VAR.
SKEwNESS
NC. CF CELLS
0.40163
0.79922
6
RtCOVERY OF INCREMENT
DATA IN
ASCEND IMG
ORCER
0.0785
0.i OC 3
0.1010
0.13C4
0.1311
0. 14C2
0.15C1
0.16C1
0. 16C1
0.1620
0.1707
0.18C2
0.1921
0.1938
0.2001
0.2008
0.2008
0.2C60
0.2210
0.2335
0.2422
0.2902
0.2950
0.2954
0.3356
0.3756
0.4085
HISTCGRAM
CELL MID.
0.C785
C. 1445
0.2105
0.2765
0.3425
0.4085
FKEC.
3
8
10
3
1
2
XXX
XXXXXXXX
XXXXXXXXXX
XXX
X
-------
22
METHOD AND PERFORMANCE EVALUATION, ACCL , WQO
METHOD STUDY 2, NUTRIENTS
NITROGEN - NITRATE, AMPUL 3
STATISTICS, ALL DATA, ALL LABORATCRICS
MANUAL PROCEDURE
RtCCVERY OF INCREMENT FROM NATURAL WATER
INCrttMEN1 =
1.24
VAL ,
N
TKUE
M E A <\i
MEU I AN
ACCURACY
27 RANGE 1.00609
1.24 VARIANCE 0.04584
1.25022 STD. DEV. 0.21412
1.24380 CONF. LIM. (95%) 0.41968
2.822^7 PERCtNT, RELATIVE TC TRUh VALUE.
CCEF. VAR.
SKEWNESS
NC. OF CELLS
0.17126
-C.51751
t
UfcCOVERY OF INCREMF.sT
DATA IN
ASCENDING
CRCtR
,6060
,0356
. C 5 8 5
. CfcC 1
.GCC2
.0911
. 12CI
. 12C7
.1720
. 1 756
.<>UC9
. / 30 1
c3C3
.2438
.2fcC8
7Cfl
- ^ 6 C 4
. 3 0 3 5
.3301
. 3422
.35^5
. iti 10
.42C0
. 5 7C2
. 595G
.6054
.6 120
HISTCbRAM
C-LL iv I 0 .
C . 6 C t 0
e. a v 71
I . C U 4
1.2(^6
L 4 1 Cd
1.6 120
F R F (,
1
0
b
12
S
4
XXXXX
xxxxxxxxxxxx
xxxxx
-------
McTHCD AND PERFORMANCE EVALUATION, AGCL, WQO
METHOD STUDY 2, NUTRIENTS
23
NITROGEN - NITRATE, AMPUL 4
STATISTICS, ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY OF INCREMENT FRCM NATURAL fcATfcrf
INCREMENT = 1.08
N 27 RANGE 1.44420
TRUE VAL. 1.08 VARIANCE 0.06009
MbAN 1.15503 STD. LEV. 0.24514
MEDIAN 1.15105 CONF. LIM. (95%) 0.480H7
ACCURACY 4.11601 PERCENT, RELATIVE TO TRUE VALUE.
CCEF. VAR.
SKEtoNfcSS
NO. CF CFLLS
C.21224
C .6924 1
6
RECOVERY 0F INCREMENT
DATA IN
ASCENCING
ORDER
0.5060
0.8911
0.9500
0.9602
1.0103
1.0104
1.0320
1.0407
1.0438
1.1010
1.1301
1. 13C8
1.1501
1.1510
1.1585
1.16CI
1. 1708
1.1756
1.2200
1.2235
1.2322
1.2356
1.2854
1.3120
1.4450
1.5085
1.9502
HISTOGRAM
CELL MID.
C.5060
0.7948
1.0836
1.3725
1.6613
1.9501
FREC,
1
1
18
6
0
1
X
X
xxxxxxxxxxxxxxxxxx
-------
24
Orthophosphate-Phosphorus, The Single Reagent Method
Level: .029 - .038 mg/liter, Orthophosphate-Phosphorus
The single reagent method for orthophosphate had a consistent negative
bias of 5 - 13% at these low levels. In Figures 3A and 3B, though the dis-
tilled water samples showed the greatest bias, both distilled and natural
water samples show low recovery so the bias is probably inherent in the
method. It should be pointed out that the 5 - 13% bias at levels of 0.029 -
0.038 mg P/liter is only an absolute difference of .001 - .003 mg/liter. At
the .029 - .038 mg/liter level in natural waters, orthophosphate values will
deviate only .016 - .020 mg/liter from mean values with a 95% probability.
Level: .335 - .383 mg/liter, Orthophosphate-Phosphorus
At this higher level of orthophosphate, the method showed greatly improved
accuracy with a negative bias of 1.2% to 2.7%. Figures 3C and 3D show almost
identical pictures of this tight precision and reduced negative bjas. At the
95% confidence level, the orthophosphate values will devjate .035 - .045 mg
P/liter from mean values at the .335 - .383 mg P/liter levels in natural water.
The statistical data from Method Selection Study 1 (4) on the single
reagent method for orthophosphate agree well with the data obtained here
Method Selection Study 1
This
Study
Distilled
Water
Natural
Water
Distilled
Water
Natural
Water
Level added,
mg/1
0.228
.228
.383,
.335
.383, .335
X Recovery,
mg/1
0.231
.229
.375,
.331
.374, .326
Standard Devi-
ation, mg/1
.007
.004
.019,
.014
.023, .018
Accuracy, as
% Bias
+2.38
+ 1.39
-1.58,
-1.23
-------
25
Summary - Single Reagent Method for Orthophosphate
The single reagent method for orthophosphate showed standard deviations
of .008 - .023 mg P/liter and negative bias' of 1 - 6% in the 0.029 - 0.383
-------
26
FIGURE 3 A-D
TWO SAMPLE CHARTS FOR ORTHOPHOSPHATE, mg P/liter
070
056
.042
028
014
0 0
1 1 1 1
i i i i i
3A
DISTILLED WATER
t
-g "
i
i i i i
AMPLE 1
k 1 1 1 1
0 014 028 .042 .056 070
,040
030
020
0 01
~i 1 i i 1 1 ; 1 r
3B
. NATURAL WATER
J L
SAMPLE
0 01 020
040 050 .060
40
1
i i i i i i i
i
3C
DISTILLED WATER
38
"
36
-co
LU
_ Q_
£
34
CO
«
-
32
-
| 1
-
-
«
0 30
SAMPLE 4
1 1 1 1 1 1 1
1
i
J 30
.32 34 .36 .38
,4(
45
41
- 37
.33
.29
0.25
i i i i i i
3D
i i i
NATURAL WATER
-
-LfcJ
-
o_
i
1
I
oo
~\
9
~
*
SAMPLE 3
i i i i i i
1 1 1
.25 .29 33 .37
-------
METHOD AND PERFORMANCE EVALUATION, ACCL, WQO
METHOD STUDY 2, NUTRIENTS
27
PHOSPHATE - SCL., CRTHC, AMPUL 1
STATISTICS, ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY OF INCREMENT FROM NATURAL WATER
INCREMENT = 0.C29
N 26 RANGE 0.04610
TRUE VAL. 0.029 VARIANCE 0.00010
MEAN 0.02744 STD. CEV. 0.01030
MEDIAN 0.02771 CONF. LIM. (95%) 0.02019
ACCURACY -4.9^894 PERCENT, RELATIVE TO TRUE
COEF. VAR.
SKEWNESS
NO. OF CELLS
VALUE
RECOVERY OF INCREMENT
DATA IN
ASCENCING
ORDER
0.01C0
O.OICO
0.0132
0.0170
0.0170
0.0200
0.0211
0.0221
0.0234
0.0240
0.0240
0.0250
0.0273
0.0281
0.0281
0.0303
0.0304
0.0312
0.0312
0.0351
0.0360
0.0360
0.0371
0.0382
0.0407
0.0561
HISTOGRAM
CELL MID.
0.0100
0.0192
0.0284
0.0377
0.C469
0.0561
FREG.
3
6
10
6
0
1
XXX
xxxxxx
xxxxxxxxxx
-------
28
MtI HOD AND PERFORMANCE EVALUATION, ACCL , WQO
fFThCD STUOY 2, NUTRIENTS
PHGbPHATE - SCL. » CRTHO, AMPUL 2
STATISTICS, ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
RECCVERY OF INCREMENT FRCf NATURAL HATER
INCREMENT = O.C38
N 26 RANGE 0.03596
TKUt v'AL. 0.038 VARIANCE 0.00006
MtA.\ 0.03560 STC. CfcV. 0.00836
MfcUlAN 0.03510 CONF. LIM. C95%) 0 .0 I638
ACCURACY -6.00358 PERCENT, RELATIVE TO TRUE VALUE.
CCEF. VAR.
SKEWNESS
NC. CF CELLS
C.23489
C. 11246
6
HCClVERY of INCREMENT
DATA IN
ASCENCING
CRCER
0.C172
0.U240
0.0260
C.C26C
0 . C 2 fc I
0.C2SC
O.UiCC
0. C3C0
0.C314
O.C33C
0.C34O
C.C343
C . C 3 5 I
C.C35 L
0. (J 3 c 3
C.C371
O.C IS?
C.C4C0
0.C4CC
0.C4C4
0. CM I
C.042?
0.C4 j I
O.C^Sl
0.C5C7
C.U532
HISTCGRAf
CcLL CIC.
n . c 17 2
0.C<:44
C . C 3 16
C.C388
C.C4 6C
0.C532
FREC.
1
3
10
8
2
?
X
XXX
xxxxxxxxxx
XXXXXXXX
XX
-------
Nl T HDL AMU PERFORMANCE E V A L U A \ I G N t A£CL , WQO
METHOD STUDY 2, NLTKIENTS
29
PHCSPhATE - SCL., TRTHC, AMPUL 3
STATISTICS, AH DATA, ALL LABORATORIES
MANUAL PROCEDURE
RfcCLVEKY nF INCREMEM F R C M \ATURAL k A T F R
INCKfcNE»\r = C . 3d3
C.06151
C.C6801
t
N cb RANGE 0.12621
TriUE VAL. C. 3 a 3 VARIANCE 0.00052
KEAN 0.37360 STC. CEV. 0.C2298
*LUIA.\ 0 . 372 3G CONF. LIM. (95%) 0.04504
ACCURACY -1.75 849 PERCENT, RELATIVE TC TRUE VALUE.
CLbF. VAR.
SKEIrA'fcSS
NC. LF CFLLS
RLCCVCRY C'F IKCRFf'fc'NT
LATA IN
ASCEND ING
ORDER
C. 3100
0.333C
0. 3540
0.3580
C.36CO
0. 3641
0.3670
0.3683
0. 37CO
0.3704
0.3711
0.3711
C.3712
O.J733
0.3754
0. 376C
0.3770
0.378C
0.3800
0.38C2
0.3651
0.3871
0.3882
0.3971
C.4 107
0.4 362
HISTObRAM
CELL ML.
C.3100
C.3352
C.3605
0 . 3 ri 5 7
0.4110
C . 4 3 6 2
FRbC.
X
X
xxxxxxxxxxx
xxxxxxxxxxx
x
-------
30
METHOD AND PERFORMANCE EVALUATICN» ACCL, WQO
METHOD STUDY 2, NUTRIENTS
PHOSPHATE - SCL., CRTHC, AMPUL 4
STATISTICS, ALL CATA, ALL LABCRATORIES
MANUAL PRCCbDURt
RECOVERY OF INCREMENT FRUM NATURAL WATER
INCREMENT = 0.335
M 26 RANGE 0.07070
TKUE VAL. 0.335 VARIANCE 0.00031
MEAN 0.32579 STD. CEV. 0.01767
MEDIAN 0.32855 CONF. LIM. (95%) 0.0 3^63
ACCURACY -2.74782 PERCENT, RELATIVE TO TRUE VALUE.
CCEF. VAR.
SKEWNESS
NC. OF CELLS
0.05425
-C.35868
6
RECCVERY OF INCREMENT
CATA IN
ASCENDING
ORDER
0,
0.
0.29C0
0.2940
0. 297C
0.30C0
0. 3 0 74
0.31C1
32CC
3 20 3
C. 32C4
C.3240
0.324 1
0.3253
0.327C
0.33C0
0.33C1
0.331L
0.3320
0.3342
0.^350
0.3351
C. 34CC
C.3411
0. i462
0.3462
0.3482
0.36C7
HIS TC GR AM
CELL fllJ.
C.2900
C.3C41
C.3 183
0.3324
0 .3466
0.3607
FREt.
3
3
6
ft
5
1
XXX
XXX
XXXXXX
XXXXXXXX
xxxxx
-------
31
Kjeldahl Nitrogen Method
The theoretical values for nitrogen can be calculated independently of
the method of analysis. However, because of the extreme dependence of the
Kjeldahl nitrogen test upon the type of digestion used it is difficult to
obtain the same precision and accuracy as those obtained with methods for
elemental analyses.
.20 - .31 mg/liter Level of Kjeldahl Nitrogen
The Kjeldahl test showed standard deviations of .15 - .22 mg N/liter
with distilled water and .20 - .25 mg N/liter with natural water samples
at the 0.2 - 0.3 mg/liter level. Surprisingly, there was a greater bias in
the distilled water samples 24-31% positive bias, than in the natural water
samples, with 5-16% positive bias.
These positive bias values are shown as a concentration of values in
the (+,+) quadrants in Figures 4A and 4B. The precision at these levels
was poor also, with one standard deviation being 56-59% of the added levels
for distilled water samples and 75-85% of added levels for natural water
samples. In Figures 4A and 4B the data extended along the 45° slope
indicate the systematic error. The perpendicular spread of values away
from the 45° slope indicate the serious imprecision in the method. At
the 95% confidence interval, Kjeldahl nitrogen levels of 0.2 - 0.3 mg/liter
will deviate ± .4 - .5 mg/liter from mean values (100-200%) in natural
water samples.
4.10 - 4.61 mg/liter Level of Kjeldahl Nitrogen
A significant improvement occurred m the Kjeldahl test at the 4 mg/liter
level. Accuracy values improved to a low 1-2% positive bias for both distilled
and natural waters. These very low levels of bias were offset by continuing
imprecision with one standard deviation being 30-31% added values for
-------
32
At the 95% confidence interval in natural waters, Kjeldahl nitrogen levels
of 4 mg/liter deviate 2.1 to 2.3 mg N/liter from mean values. These
deviations shown by the close grouping of values along extended 45° slopes
in Figures 4C and 4D indicate this error is almost entirely systematic
error in the method as applied in this study.
Summary - Kjeldahl Nitrogen Analyses
The Kjeldahl digestion and distillation procedures perform with very
limited accuracy and precision at <1 mg/liter levels as might be expected
with an operationally-defined parameter. At a level of 4 - 5 mg/liter,
accuracy is greatly improved but precision is not. Major variables in the
complex procedure are not completely controlled. Two quality-control
factors that may give further improvement in results are greater care in
protection of the samples from contamination by ammonia during analysis,
and routine analysis of standard samples such as ammonium chloride and
-------
33
FIGURE 4 A D
TWO SAMPLE CHARTS FOR KJELDAHL NITROGEN, mg N/liter
1 1 1
1 1 ! 1 1 I
4A
-
DISTILLED WATER
~<£D
UJ
a?
-CO
.
J
f* #
4
> #
-
SAMPLE 5
l l l 1 l l
1 % *1
0.0 .2
.4 6 8 1 0
1.00
76
52
.28
*04
0.2
n 1 1 1 r r
~i r
46
NATURAL WATER
* '* '*
i
* : SAMPLE 5
J I I jJ I I L_
J I
0 2 *04 28 52 76 1 00
i i i i i
4C
DISTILLED WATER
j
i i i i
~
ft* *
- CO *
Ul
1
v> . ,
SAMPLE 7
i 1 1 1 1 1
1 1 1 1
0.0 1.6 3.2 4.8 6.4 8.0
7 0| 1 i 1 rj
4D I
NATURAL WATER)
6 Oh
5.0-
n 1^ r
4.0 "5
3.0-
2.0L
SAMPLE 8
i i ' ill I I i i
-------
34
METHOD AND PERFORMANCE EVALUATION, AQCL , WQO
METHOD STUDY 2, NUTRIENTS
NITROGEN - KJELD., TOT. » AMPUL 5
STATISTICS, ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY OF INCREMENT FRCM NATURAL HATER
INCREMENT = C.31
0.75438
0.36371
6
N 31 RANGE 1.05234
TRUE VAL. 0.31 VARIANCE 0.06081
MEAN 0.32689 STD. DEV. 0.24660
MEDIAN 0.29180 CONF. LIM. (95%) 0 . 4 83 3^
ACCURACY 5.45003 PERCENT, RELATIVE TG TRUE VALUE.
COEF. VAR.
SKEWNESS
NO. OF CELLS
RECUVERY CF INCREMENT
OATA IN
ASCENDING
ORDER
-0.1796
-0.0994
0.0312
0.0612
0.0814
0.1215
0.1320
C.23CI
0.2430
0.2439
0.2542
0.2670
0.2718
0.2728
0.2730
0.2918
0.2919
0.3118
0.3210
0.3617
3739
,3817
3840
0.4C5C
C.4ie2
0.6539
0.66 56
0.6908
0.7C29
0.8027
0.8726
0,
o.
0,
HISTCGRAM
CELL MIC.
-0. 1796
0.C307
C.2412
C . 4 5 1 7
0.6621
0.8726
FREC.
2
5
12
6
4
2
XX
XXXXX
XXXXXXXXXXXX
XXXXXX
XXXX
-------
METHOD ANC PERFORMANCE EVALUATION. ACCL, WQO
METHOD STUCY 2, NITR IfcNTS
35
NITROGEN - KJELD.t TCT,» AMPUL 6
STATISTICS. ALL DATA, ALL LABORATORIES
MANUAL PROCEOURE
RECOVERY OF INCREMENT FRCM NATURAL WATER
INCREMENT = C.2C
CCEF. VAR. 0.85373
SKEWNESS C.33543
NO. OF CELLS 6
VALUE.
N 31 RANGE 0.77094
TRUE VAL. 0.20 VARIANCE 0.03891
MEAN 0.23107 STD. DEV. 0.19727
MEDIAN 0.20100 CONF. LIM. (95%) 0.38665
ACCURACY 15.53711 PERCENT, RELATIVE TC TRUE
RECOVERY OF INCREMENT
DATA IN
ASCENCING
ORDER
-0.1169
-0.0994
0.C012
0.01C1
0.05C3
0.0662
0.0708
0.0719
H ISTCGRAM
o.oeie
0.1239
CELL MID.
FKEC.
0.1428
0.1518
-0. 1169
2
XX
0.1518
0.0371
7
XXXXXXX
0.1915
C.1913
12
XXXXXXXXXXXX
0,1942
0.3455
3
XXX
0.2010
C.4997
5
XXXXX
0.2040
0.6539
2
XX
0.2117
0.2170
0.2319
0.2617
0.342 7
0.4050
0.4139
0.4426
0.45C8
0.4556
0.4730
0.5214
0.5829
-------
36
MfcThOU AND PERFORMANCfc EVALUATION, ACCL , WQO
METHOD STUDY 2, NUTRIENTS
NITROGEN - KJELD., TCT. , AMPUL 7
STATISTICS, ALL CATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY CF INCREMENT FRCM NATURAL WATER
INCREMENT = 4.10
N 31 RANGE 3.97270
TKUE VAL. A.10 VARIANCE 1.11570
MEAN 4.14219 STO. DEV. 1.05626
MEDIAN A.26180 CONF. LIM. C95%) 2.07027
ACCURACY 1.02903 PERCENT, RELATIVE TO TRUE VALUE.
COEF. VAR.
SKEWNESS
NO. OF CELLS
0.25500
-C.46739
6
RECOVERY CF INCREMENT
DATA IN
ASCENDING
ORDER
2 . CO 15
2.C 809
2.1312
2.3920
3.1219
3. 13C4
3.3049
3.3670
3.9614
3.9716
4.0056
4.0209
4.0739
4.1617
, 1682
2818
,2827
,32 18
,3418
,3539
4.5139
4.56C1
-4 . 8 1C 8
4.tJ43C
5.0930
5.2427
5.3039
5.4050
5.4626
5.7229
5.9742
4.
4 ,
4,
4 ,
4 ,
4,
HISTOGRAM
CELL MIC.
, C (J 15
,7960
,5905
,3851
,1796
5.9741
FREC.
4
2
4
12
7
2
xxxx
XX
xxxx
xxxxxxxxxxxx
xxxxxxx
-------
MtTHOD AND PERFORMANCE EVALUATION, AGCL, WQO
METHOD STUDY 2, NUTRIENTS
37
NITROGEN - KJELC.t TCT . » AMPLL 8
STATISTICS, ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY OF INCREMENT FRCM NATURAL WATER
INCREMENT = 4.61
0.26282
C.1C507
fc
N 31 RANGE 4.71329 CCEF. VAR.
TRUE VAL. 4.61 VARIANCE 1.41948 SKEHNESS
MEAM 4.53315 STD. DEV. 1.L9142 NO. OF CELLS
MEDIAN 4.57395 CONF. LIM. (95%) 2 . 33 5 1 8
ACCURACY -1.66690 PERCENT, RELATIVE TO TRUE VALUE.
RECOVERY OF INCREMENT
DATA IN
ASCENOING
ORDER
2.2509
2.3619
2.6349
2.7015
2.8712
3. 4bG 5
3.6219
3.6670
HISTOGRAM
4.2214
4.3682
CELL MIU.
FREC.
4.4117
4.4216
2.2509
4
XXXX
4.4409
3.1935
3
XXX
4.5139
4.1362
9
XXXXXXXXX
4.5727
5.0768
9
XXXXXXXXX
4.5739
6.0215
4
XXXX
4.7139
6.9641
2
XX
4.7456
4.7800
4. 8418
4.8418
4.8618
4.9050
5. 1708
5.2030
5.5930
5.8627
5.9526
6.3039
6.6929
-------
38
Total Phosphorus - The Persulfate Digestion and Single Reagent Method
0.110 - .132 mg/liter Level of Total Phosphorus
At this low level, the total phosphorus was recovered with accuracy
of + .6% to -1% bias in distilled water and 3-12% positive bias in natural
waters. This positive bias in natural water (Figure 5B) is in contrast
to the 5-13% negative bias observed for orthophosphate. Although 12% is
a relatively high bias, the level is only 0.01 - 0.026 mg/liter which is
barely above the minimum detectable level. At this fractional mg/liter
level, the total phosphorus method operated with limited precision, showing
a 95% chance for variability of *.06 - .10 mg/liter from mean values in
natural water samples containing .12 - .13 mg P/liter.
The precision was similar for distilled and natural water samples
so the variation relates to the method not to the sample type. It is also
similar to the precision found for orthophosphate in samples 1 and 2.
The apparently greater spread of values shown in Figure 5A over those
shown in Figure SB is the result of 2.5 scale expansion in 5A over 5B.
The accuracy of the test is clearly shown in the tight centering of values
around the true value intersect.
0.772 - .882 mg/liter Level of Total Phosphorus
At these higher fractional levels, the total phosphorus analysis
showed -2% to +3% bias in distilled and natural water samples. Figures
5C and 5D show this tight grouping of values around the true value
intersect. At the 95% confidence interval, total phosphorus mean values
of .81 and .89 mg/liter deviated *0.25 mg P/liter in natural waters.
Summary - Total Phosphorus Analyses
The accuracy and precision of the single reagent method for ortho-
phosphate are reflected in the tight grouping and limited scatter of most
-------
39
mg P/liter samples. This grouping also emphasizes the extreme values obtained
by a few laboratories.
The precision was lessened apparently by the additional variable, the
persulfate digestion step. Perhaps this also changed the negative bias of
-------
40
FIGURE 5 A D
TWO SAMPLE CHARTS FOR TOTAL PHOSPHORUS, mg P/liter
.18
16
.14
.12
10
3.G8
1 1
5A
i i i i i i
DISTILLED WA"
ER
-
.CO
LU
J
< ft
CO ^
|
>
_
"
1 1
SAMPLE 5
1 1 1 1 I I
08 .10
.12 .14 .16 18
.40
.32
.24
.16
08
0 0
~i 1 1 1 1 r
5B
NATURAL WATER
/
SAMPLE 5
J L.
I I »
0.0 .08 .16
24
.32 40
1
i i i i i
5C
i i i
DISTILLED WATER
-
-
-
,*
"7*
*
QO
UJ
-
~v>
1
SAMPLE 7
¦ i i i i
i i i
0.4
.54 .68 .82
.96 1.10
1.5
1 3
0.5
i i i
1 1 1 1 1 1
5D
-
NATURAL WATER
-Co
LaJ
-
-
**
«
.
w
/
1
( 1 1
SAMPLE 7
i 1 1 1 1 1
CD
CJ1
J
-------
MtThOC ANC PERFORMANCE EVALUATION, AGCL, WQO
METHOD STUDY 2, NUTRIENTS
41
PHOSPHORUS - TCTAL, APPUL 5
STATISTICS, ALL OATA, ALL LABORATORIES
MANUAL PROCtDURE
kECOVERY OF INCREMENT FRCP NATURAL Vm A f E R
INCREMENT = O.IIO
CCEF. VAR. 0.27410
SKEWNESS 2.59996
NC. GF CELLS 6
VALUE.
N 31 RANGE 0.16691
TRUE VAL. 0.110 VARIANCE 0.00109
f*EAfg 0. 1206a STC. CEV. 0.0330S
Mb D I AN 0.11318. CONF. LIM. C95%) 0 .06 4 84
ACCURACY 3.09078 PERCENT, RELATIVE TC TRUE
RECLVERY CF INCREMENT
DATA IN
ASCENCING
ORDER
0.0841
0.0848
0.0921
0.0943
0.0992
0.1011
0.1050
0.1051
0.1053
C.1061
0.1063
0.1091
0. 11C 1
0.1111
0.1111
0.1111
0.1131
0. 1141
0.1142
0.1 162
0.1198
0.1201
0. 1210
0.1212
0.1214
0.1222
0.1272
0.1321
0.1390
C.1426
0.1540
0.2162
0.2510
HI STGGKAM
CELL MID.
C .0841
0. 1175
0.1509
C. l«42
0.2176
C.2510
FREG.
5
23
3
0
1
1
xxxxx
xxxxxxxxxxxxxxxxxxxxxxx
-------
42
Mb THOU AND PERFORMANCE EVALUATION, ACCU WQO
METHOD STUDY 2, NUTRIENTS
PHOSPHORUS - TOTAL» AMPUL 6
STATISTICS, ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
RECGVERY OF INCREMENT FRCM NATURAL WATER
INCREMENT = 0.132
0.33055
2.68853
6
N 33 RANGE 0.31787
TRUE VAL. 0.132 VARIANCE 0.00262
MEAN 0.15492 STD. DEV. 0.05121
MEDIAN 0. 14502 CONF. LIM. C95%) 0 .100 37
ACCURACY 11.99398 PERCENT, RELATIVE TC TRUE
COEF. VAR.
SKEWNESS
NO. CF CELLS
VALUE'.
RECOVERY OF INCREMENT
DATA IN
ASCENDING
ORDER
0.0641
0.1011
0. 1291
0.1291
0.1311
0.1311
0.1311
0.1311
HISTOGRAM
0.1312
0.1312
CELL MID.
FREC.
0.1314
0.1333
C.0641
1
X
0. 1341
0.1277
23
xxxxxxxxxxxxxxxxxxxxxxx
0.1343
0.1913
8
xxxxxxxx
C.1352
C.2549
0
0.1382
0.3184
0
0. 1450
0.3820
1
X
0. 1461
0. 1471
0.1482
0.1482
0.1503
0.1540
0. 1541
0. 1610
0. 1656
0.1678
0.1840
0.20CI
0.2088
0.2161
0.2162
-------
MCThOC AND PERFORMANCE EVALUA TIGN» AQCL, WQO
METHOD STUDY 2, NUTRIENTS
43
PHOSPHORUS - TOTAL, AMPUL 7
STATISTICS, ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
RbCCVERY OF INCREMENT FRLM NATURAL WATER
INCREMENT = 0.882
C. 14 437
1.59664
fc
N
TkUE VAL.
MfcA,\
Men ian
ACC'.RACY
33
0.882
0.89004
0.88409
0.9126 0
RANGE
VARIANCE
STD. DEV.
CON IF LIM. (95%)
0.76499
0.01651
0.12850
0.251 86
CCfcF. VAR.
SKEfcNESS
NC. OF CELLS
PERCENT, RELATIVE TC TRUE VALUE.
RECUVERY OF INCREMENT
DATA IN
ASCENDING
ORDER
0.6421
0.6690
0.6921
0. 7683
0.80C0
0.8051
0.8160
0.6273
0.8503
C.8530
0.8561
0.87C2
C.87C8
0.8742
0.8780
0.8811
0.8840
0.89C2
0.89C2
0.8911
0.8941
0.8951
0.9041
0.9446
0.9581
3.96C0
0.9614
0.9640
0.9711
0.99C2
1. 0048
1.0062
1.4071
HISTOGRAM
CELL MID.
C.6421
0.7951
0.9481
1.1011
1.2541
1.4071
FREG.
3
10
19
0
0
1
XXX
xxxxxxxxxx
-------
44
METHCC ANC PERFORMANCE EVALUATION, ACCL , WQO
METHOD STUDY 2, NUTRIENTS
PHOSPHORUS - TOTAL~ AMPUL 8
STATISTICS, ALL DATA,
MANUAL PROCEDURE
RECOVERY OF INCREMENT
ALL LABORATORIES
FRCM NATURAL WATER
INCREMENT = 0.772
N
T*Ub VAL,
MEAN
M t D IA i\
ACCURACY
33
0.772
0.81341
0.79418
2.96449
RANGE
VARIANCE
STC.
CONF.
PERCENT
CEV.
LIM. (95%)
, RELATIVE
0.77719
0.01702
0.13048
0.2557^
TO TRUE
COEF. VAR.
SKEWNESS
NO. OF CELLS
C.16041
2.82262
6
VALUE
RECOVERY OF INCREMENT
DATA IN
ASCtNCING
ORDER
0.6290
0.6603
0.6781
0.70C0
0.7002
0.7151
0.7153
0.771C
HISTCGRAM
0.7711
0.7711
CELL MIC.
FRhU
0.7711
0.78C8
0.6290
5
xxxxx
0.7811
0.7044
22
xxxxxxxxxxxxxxxxxxxxxx
0.7811
C.9399
5
xxxxx
0.7841
1.0953
0
0.7931
1.2507
0
0.7941
1.4062
I
x
C.7990
0.8C98
o.ai02
0.6200
0.8200
0.8260
0.8361
0.8373
0.85C2
0.8602
0.8646
0.90S0
0.9114
0.9182
0.9661
-------
45
Characterization of Natural Waters
The following are examples of the natural waters tested in this study:
Water
Source
Spec.
Cond.
PH
TDS
Total
Hardness
Acidity
Alkal mity
CI
so4
Mary's River
139
7.2
--
34
38
12
<10
Missouri River
500-
1000
6.5-
8.5
500-
1000
150-
1000
100-
250
<50
100
500
Raritan Bay
19000
7.6
22,500
>500
890
10,200
>500
Ohio River
390
6.9
259
147
30
25
100
Raritan Bay
36000
7.8
25,700
5400
82
14000
>500
Pacific Ocean
14,800
8.1
--
5700
110
--
2450
Chena River
213
7.4
145
100
86
1.8
26
Stonelick Creek
306
7.9
216
151
105
10
31
Indiana Harbor
Canal
500-
1000
6.5-
8.5
100-
500
50-
150
50-
150
<50
50-
150
San Joaquin
River
100-
500
6.5-
8.5
100-
500
<50
<50
<50
<50
Colorado River
1300
8.2
850
340
213
136
355
Deschutes River
118
7.85
103
51
40
8.5
--
Detroit River
300
8.2
--
--
76
40
<50
Lake Ontario
100-
6.5-
8.5
100-
500
50-
150
50-
100
<50
<50
Nashua River
180
6.8
37
84
28
20
20
Shagawa Lake
100-
500
6.5-
8.5
100-
500
<50
50-
100
<50
<50
Rock Creek
1440
6.3
1570
228
670
5
-------
46
Interferences from Natural Waters
Throughout this study, laboratories reported extreme values in
recovery of increments from natural waters such as estuaries, fresh
waters high in dissolved solids, and waters heavily polluted with
industrial wastes, any of which might interfere with analyses. However,
an examination of the recoveries of increments from distilled water
samples from these laboratories showed about the same pattern of extreme
values. This suggests that the imprecision of their data was largely
related to technique, and that the only effect of the natural water
samples was to exaggerate their difficulties. Based on this study, the
WQO methods of analyses are applicable to varying types of fresh and
-------
47
REFERENCES
1. Youden, W. J. 1967. Statistical Techniques for Collaborative Tests.
AOAC, Inc., Washington, D.C.
2. FWPCA Official Interim Methods for Chemical Analysis of Surface Waters.
September 1968. Analytical Quality Control Branch, Division of Research,
FWPCA.
3. Larsen, K. E. 1969. The Summarization of Data. J. Qual. Technol.,
Vol. 1, No. 1, 1968.
4. Method Selection Study 1. A Comparison of Three Modifications of the
Single Reagent Method for Soluble Orthophosphate. April 1969,
Analytical Quality Control Laboratory, Division of Water Quality
-------
APPENDIX 1
-------
METHOD AND PERFORMANCE EVALUATION, AQCL, WQO
METHOD STUDY 2, NUTRIENTS
NITROGEN - AMMONIA
ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY
OF INCREMENT FROM
DISTILLED
WATER, MG/
AMPUL
AMPUL
AMPUL
AMPUL
1
2
3
4
INCREMENT
, MG/L
0.26
0.21
1.71
1.92
-LAB
ANALYST
NO.
NO.
101
1
0. 19
0. 19
1.75
1.94
101
2
0.20
0.20
1.71
1.88
102
1
0.38
0.35
1.73
1.90
106
2
0.27
0.23
1.39
2.10
107
1
0.25
0.21
1.55
1.85
107
4
0.26
0.21
1.60
1.86
110
1
0.11
0.15
1.54
1.80
110
2
0.14
0.19
1.98
2.24
110
3
0.18
0.45 R
1.72
1.96
110
4
0. 16
0.27
1.62
2.01
110
5
0.25
0.19
1.68
1.6B
112
1
0.24
0.21
1.68
1.90
113
1
0.24
0.20
1.69
1.80
113
3
0.20
0.18
1.56
1.82
113
4
0.23
0.21
1.61
1.81
114
1
0.41
0.34
2. 10
2. 10
115
2
0.28
0.25
1.69
1.88
116
3
0.26
0.23
1.68
1.89
121
1
0.23
0.24
1.66
1.90
123
1
0.26
0.22
1.77
1.73
123
2
0.31
0.26
1.7B
1.98
125
3
0.25
0.24
1.60
1.76
126
2
0.20
0.13
2.11
2.65 R
126
3
0.32
0.15
2.23R
2.69 R
127
2
0.16
0.24
1.72
1.96
134
1
0.51 R
0.44 R
2. 10
2.70 R
R = REJECTED
METHOD AND PERFORMANCE EVALUATION, AQCL, WQO
METHOD STUDY 2, NUTRIENTS
NITROGEN - AMMONIA
ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
COMPUTED RECOVERY OF INCREMENT FROM NATURAL WATER, MG/L
AMPUL
AMPUL
AMPUL
AMPUL
1
2
3
4
INCREMENT
, MG/L
0.26
0.21
1.71
1.92
LAG
ANALYST
NO.
NO.
101
1
0.2102
0.1402
1.7102
1.8602
101
2
0.1602
0. 1402
1 .7302
1.8302
102
1
0.3150
0.3850
1.4449
1.6349
107
1
0.2401
0.2201
1.4801
1.7701
107
4
0.2401
0.2001
1.6201
1.8301
110
1
0.1300
0.1500
1.6000
1.8400
110
2
0.1600
0.2600
2.1000
2.1600
no
3
0.2470
0.6370 R
2.4570 R
2.8070 R
no
4
0.0903
0.3003
1.5403
1.9902
110
5
-0.7150 R
-0.7650 R
0.8150 R
0.8150 R
112
1
0.2301
0.1801
1.7100
1.8701
113
1
0.2303
0.1703
1.6603
1.8003
113
3
0.2001
0.1701
1.5701
1.8401
113
4
0.2003
0. 1803
1 .6803
1.8803
114
1
0.1337
0. 1337
1.6637
1.8637
115
2
0.2507
0.2107
1 .7107
1.8707
116
3
0.2403
0.2003
1.6503
1 .8603
121
1
0.1602
0.1902
1 .6302
1.8202
123
1
0.2703
0.2203
1.6903
1.8303
123
2
0.2906
0.2206
1.7406
1.9505
125
3
0.2802
0.2102
1.6102
1.8102
126
2
0.1206
0.0 106
2. 1406
2.7306 R
126
3
0. 1705
0.0505
2.2105
2.2604
127
2
0.1475
0.2475
1.6975
1.9475
134
1
0.3906
0 .3 706
1.9 206
1 .8706
-------
MtThOi: AND PC3F ORP A\C t EVALUAT I ON « AQCL, WQO
tfETHOD STUDY z, NUTRIENTS
NIJROGtN - NITRATE
ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY
GF iNCREftNT FROM
DISTILLED
WATER, MGi
AMPUL
AMPUL
AMPUL
AMPUL
1
2
3
4
I^CftEMENT
, MG/L
0.16
0. 19
1.24
1.08
LAB
ANALYST
NO.
NU.
101
1
0.00
O.OOR
1.10
0.92
101
2
0.14
0.14
1.08
1.28
102
?
0.13
0.16
1.28
1.12
106
2
0.11
0.13
1.21
1.11
107
4
0.16
0.19
1.24
1 .14
10?
5
0.16
0.19
1. 30
1.10
110
1
0.09
0. IB
1.20
1.22
110
2
0.08R
0.18
1.22
1.24
110
3
0.12
0.19
1 . 8 7 R
2.01R
110
4
0. 14
0. 19
1.47
1.31
110
5
0.10
0.10
1.10
1.00
112
1
0. 14
0.17
1.10
0.97
113
1
0.14
0.18
1.26
1.11
113
3
0.12
0. 16
1.13
1.03
I L 3
4
0.19
0.24
1.65
1.40
U4
1
0.10
0.10
1.30
1. 10
IL5
1
0.16
0.20
1.31
1.08
115
2
0.15
0.18
1.19
1.06
116
4
0.12
0.12
1.23
0.98
121
1
0. 16
0.20
1.21
1.11
122
1
0.15
0.18
1 . 10
1.21
123
1
0 . 20
0. 37R
1.23
1.53
123
2
0.12
0.22
1.44
1.24
125
3
0. 14
0.17
1.08
1.00
126
2
0.10
0.16
1 .16
1.19
126
3
0. 16
0.22
1.46
1.32
127
2
0. 16
0.20
1.22
1.06
128
1
0. Id
0.21
1.25
1.12
134
1
0. 12
0.12
1.30
1.04
R = REJECTED
METHOO AND PERFORMANCE EVALUATION, AQCL, WQO
METHOD STUOY 2, NUTRIENTS
NITROGEN - NITRATE
ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
COMPUTED RECUVERY OF INCREMENT FROM NATURAL WATER, MG/L
AMPUL AMPUL AMPUL AMPUL
1
2
3
4
INCREMENT
, MG/L
0.16
0.19
1.24
CD
O
LAB
ANALYST
NO.
NO.
101
1
0.2385
0.0785
1.0585
1.1585
101
2
0. 5085 R
0.4085 R
1.3585
1.5085
102
2
0.1610
0.2210
1.3810
1.1510
107
4
0.1708
0.2008
1.2 708
1.1708
107
5
0. 1708
0.2008
1.2608
1.1308
110
1
0.1756
0.3356
1. 1756
1.2356
110
2
0.2156
0.3756
1.0356
1.1756
110
3
0.0502
0.2902
1.5702
1 .9502 R
110
4
0.2454
0.2954
1.6054
1.2854
no
5
0.2060
0.2060
0.6060 R
0.5060
112
1
0.1400
0.1601
1.0601
0.9500
113
1
0.2135
0.2335
1.3035
1.2235
113
3
0.0911
0.1311
1.0911
0.6911
113
4
0.2950
0.2950
1.5950
1.4450
114
1
0.1010
0.1010
1.2009
I.1010
115
1
0.1004
0.1304
1.2804
1.0104
115
2
0.1402
0.1802
1.3301
1.1301
116
4
0.1120
0.1620
1.1720
1.0320
121
i
0.1507
0.1707
1.1207
1.0407
122
I
0. 1501
0.2001
1.2301
1.1501
123
1
0.0521
0.1921
1.6120
1.3120
123
2
0.1721
0.2422
1.3422
1.2322
125
3
0.1102
0.1402
1.0802
0.9602
126
2
0.0Q01
0.1601
1.1201
1.1601
126
3
0.1501
0.1501
1.4200
1.2200
127
2
0.1438
0.1938
1.2438
1.0438
134
1
0.0503
0.1003
1.2303
1.0103
-------
Mt T HOD Ai\0 PERFORMANCE EVALUATION, ACCL, WQO
METHOD STUDY 2, NUTRIENTS
(JrUhO PHOSPHATE
ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY
OF INCREMENT FROM
DIST ILLEO
AMPUL
AMPUL
AMPUL
1
2
3
I.NCREMfcNT
, MG/L
0.029
0.038
0.383
LAB
ANALYST
NQ.
NO.
LCI
1
0.030
0.038
0.363
101
2
0.030
0.038
0. 383
10 i
3
0.020
0.030
0.380
106
2
0.028
0.037
0. 365
lu /
1
0.028
0.035
0.375
107
5
0.0 27
0.035
0.372
110
1
0.010
0.020 R
0.350
110
2
0.010
0.020 R
0.352
110
3
0.021
0.028
0.357
110
4
0.022
0.024
0.359
110
5
o.oir
0.030
0.380
112
1
0.021
0.036
0. 378
113
1
0.070 R
0.040
0.393
113
3
0.030
0.044
0.398
11 3
4
0.028
0.038
0.384
114
1
0.030
0.040
0.400
U-3
1
0.019
0.033
0.374
IL?
2
0.030
0.050
0.380
Ufc
I
0.026
0.035
0.386
12 1
I
0.026
0.032
0.376
122
1
0.046
0.048
0.400
123
I
0.028
0.040
0.392
123
2
0.026
0.038
0.377
125
4
0.025
0.037
0.347
126
2
0.030
0.041
0.390
Uo
3
0.025
0.034
0.364
12 I
2
0.02a
0.040
0. 390
12H
2
0.025
0.032
0.310R
IJ4
1
0.019
0.031
0.370
R = REJECTED
METHOD AND PERFORMANCE EVALUATION, AQCL, WQO
METHOD STUDY 2, NUTRIENTS
ORTHO PHOSPHATE
ALL OATA, ALL LABORATORIES
MANUAL PROCEDURE
COMPUTED RECOVERY
OF INCREMENT FROM
NATURAL WATER, MG/L
AMPUL
AMPUL
AMPUL
AMPUL
1
2
3
4
INCREMENT, MG/L
0.029
0.038
0.383
0.335
LAB
ANALYST
NO.
NO.
101
1
0.0273
0.0343
0.3683
0.3203
101
2
0.0303
0.0363
0.3733
0.3253
102
3
0.021 1
0.041 1
0.3711
0.3311
107
1
0.0360
0.0400
0.3800
0.3350
107
5
0.0360
0.0400
0.3780
0.3300
110
1
0.0100
0.0260
0.3600
0.3000
110
2
0.0100
0.0240
0.3100R
0.2900R
110
3
0.0281
0.0281
0. 3641
0.3241
110
4
0.0200
0.0300
0.3540
0.3320
110
5
0.0170
0.0300
0.3 7 70
0.2970
1 12
I
0.0240
0.0290
0.3700
0.3200
113
1
0.0312
0.0392
0.3882
0.3462
113
0.0371
0.0481
0.3971
0.3400
113
4
0.0312
0.0422
0.3U02
0.3462
114
1
0.0407
0.0507
0.4107
0 .3607
115
1
0.0234
0.0314
0. 3754
0.3074
115
0.0304
0.0404
0.3704
0.3204
116
1
0.0221
0.0371
0.3871
0.3411
121
1
0.0132
0.0172
0.3712
0.3342
122
1
0.0382
0.0532
0.4362
0.3482
123
1
0.0240
0.0340
0.3760
0.3240
123
0.0250
0.0330
0.3670
0.3270
125
4
0.0170
0.0260
0.3330
0.2940
126
3
0.0281
0.0351
0.3580
0.3 10L
127
2
0.0351
0.0351
0.3851
0.3351
134
1
0.0561R
0.0431
0.3711
0.3301
-------
MC-rHCC Af.O PfRFOPMANCC EVALUATION, ACCL, WQO
METHOD STUDY 2, NUTRIENTS
KjeLDAHL NITROGEN
ALL DATA, ALL LABORATORIES
MANUAL procedure
RECOVERY
OF INCREMENT FROM
DISTILLED
MATER, MG/
AMPUL
AMPUL
AMPUL
AMPUL
5
6
7
8
INCREMENT
, MG/L
0.31
0.20
4. 10
4.61
LAB
ANALYST
NO.
NQ.
101
2
0.59
0.29
4.20
4.66
102
1
0.82
0.50
4.00
4.70
106
1
0.32
0.24
4.22
4.80
L06
2
0.32
0.22
4. 26
4.7 2
106
3
0.35
0.24
4. 30
4.57
107
I
0. 30
0.19
4.12
4.55
107
3
0.34
0.23
4.00
4.50
110
I
0.76
0.40
5.44
6.26
110
2
O.BO
0.40
5. 30
6. 10
110
3
0.41
0.29
2.90
3.50
110
4
0.78
0.61 R
5. 74
6.74
110
5
0. 10
0. 10
2.10
2.56
110
6
0.14
0.22
2.16
2.29
112
1 FW
0.16
0.10
2.45
2.35
112
1 EW
0.14
0.10
2.36
2.56
113
1
0.16
0.10
3.84
4.58
113
3
0.19
0.57
3.76
4.08
113
4
0.54
0.45
4.42
4.72
11A
1
0.44
0.43
4.80
4.80
lib
2
0. 10
0.05
2.75
3.40
116
3
0.31
0.20
4.08
4.50
117
1
0. 30
0. 30
3.78
4.44
120
1
0.04
0.06
0.03 R
0. 10 R
12 1
1
0.32
0.23
4.35
4.50
123
1
0.47
0.33
4.02
4.71
123
2
0.41
0.32
4.95
4.98
12b
1
0.54
0.19
4.20
5.00
126
2
0.4 2
0.25
6. 16
7. 19
126
3
0.35
0.23
5.23
5.45
127
2
0.28
0.02
4.06
4.72
129
3
4. 01
130
1
0. 21
0. 00
4. 47
4.6 8
134
1
0.6 1
0. 43
2. 90
2.95
FW = FRESH WATER
EW = ESTUARINE WATER R = REJECTED
in
ro
METHOD AND PERFORMANCE EVALUATION, AGCL, WQO
METHOD STUDY 2, NUTRIENTS
KJELDAHL NITROGEN
ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
COMPUTED RECOVERY OF INCREMENT FROM NATURAL WATER, MG/L
AMPUL
AMPUL
AMPUL
AMPUL
5
6
7
8
INCREMENT
, MG/L
0.31
0.20
4.10
4.61
LAB
ANALYST
NO.
NO.
101
1
0.6539
0.4139
4.3539
4.7139
101
2
0.3739
0.6539
4.0739
4.5139
102
1
0.4182
0.0682
4. 1682
4.3682
106
1
0.3118
0.1518
4.3418
4.8418
106
2
0.2718
0.1518
4.3218
4.8618
106
3
0.2918
0.0818
4.2818
4.8418
107
1
0.3817
0.2617
4.1617
4.4117
107
3
0.3617
0.2117
3.9716
4.4216
110
1
0.8726
0.4426
5.4626
5.9526
1 10
2
0.8027
0.3427
5.2427
5.8627
110
3
0.2919
0.2319
3.1219
3.6219
110
4
0.7029
0.5829
5.7229
6.6929
110
5
0.1215
0.1915
2.0015
2.7015
110
6
0.0612
0.0012
2.1312
2.8712
L 12
1 FW
0.1320
0.0719
2.3920
2.3619
112
1 EW
0.0312
0.0708
2.0809
2.2509
113
1
-0.1796
0.0503
3.3049
2.6349
113
3
0.0814
0.5214
3.9614
4.2214
113
4
0.2670
0.2170
3.3670
3.6670
114
1
0.4050
0.4050
5.4050
4.9050
115
2
-0.0994
-0.0994
3.1304
3.4605
116
3
0.3210
0.2010
4.0209
4.4409
117
1
0.6656
0.4556
4.0056
4.7456
120
1
0.4700
-0.0001
0.1223
0.0009
123
I
0.2728
0.1428
4.2827
4.5727
123
2
0.2439
0.1239
4.5139
4.5739
125
1
0.2430
-0.1169
4.8430
5.2030
126
2
0.2542
0.1942
5.9742
6.9642
126
3
0.2730
0.4730
5.0930
5.5930
127
2
0.6908
0.4508
4.8108
5. 1708
130
1
0.2301
0.0101
4.5601
4.7800
134
1
0.3840
0.2040
5.3039
6.3039
FW = FRESH WATER
-------
Mb T HOI) ANO PERFORMANCE EVALUATION, AQCL, WQO
METHOD STUDY I, NUTRIENTS
TOTAL PHOSPHORUS
ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY OF INCREMENT FROM DISTILLED HATER, MG/L
AMPUL AMPUL AMPUL AMPUL
5 6 7 8
INCREMENT, MG/L 0.110 0.132 0.682 0.772
LAB ANALYST
NO. NO.
101
1
0.108
0. 134
0.925
0.810
101
2
0. 108
0. 135
0.908
0.790
102
3
0. 140
0. 150
0.900
0.750
106
1
0.090
0. 130
0.850
0.760
lOfc
2
0.090
0.115
0.840
0.760
106
3
0. 100
0.120
0.840
0.760
107
3
0. 118
0.128
0.884
0.780
107
4
0. 114
0.126
0.876
0.790
110
1
0. 110
0.130
0.940
0.820
110
2
0. 100
0. 140
0.940
0.800
110
3
0.086
0. 102
0.606
0.678
110
4
0.096
0.112
0.706
0.778
110
5
0.100
0. 133
0.829
0.720
110
6
0.110
0. 136
0.855
0.735
112
1 FW
0. 109
0. 132
0.920
0.775
112
1 EW
0.115
0. 145
0.890
0.783
113
1
0. 121
0. 136
0.909
o.eio
113
3
0.125
0. 1 18
0.655
0.663
113
0.112
0.135
0.825
0.800
IU
1
0. 120
0. 140
0.920
0.810
115
1
0. 110
0.133
0.988
0.894
116
1
0.112
0.138
0.893
0.807
117
1
0. 110
0.132
0.452 R
0. 750
120
1
0. 146
0. 154
0.800
0.870
121
1
0. 108
0. 120
0.892
0.747
122
1
0.120
0.120
0.800
0.770
123
1
0.118
0. 128
0.940
0.840
123
2
0.107
0.132
0.911
0.788
125
4
0.10 2
0. 125
0.833
0.665
126
2
0. 109
0.132
0.863
0.758
126
3
0.127
0. 157
1.094
0.961R
127
2
0.115
0.130
0.880
0.799
128
2
0. 140
0. 122
0.880
0.750
129
3
0.92 3
130
1
0.150 R
0.170 R
0.665
0.625
134
1
0.096
0. 106
0.597
0. 654
FW =
FRESH WATER
EW =
ESTUARINE WATER
R = REJECTED
METHOD AND PERFORMANCE EVALUATION, AQCL, WQO
METHOD STUDY 2, NUTRIENTS
TOTAL PHOSPHORUS
ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
COMPUTED RECOVERY
OF INCREMENT FROM
NATURAL WATER, MG/L
AMPUL
AMPUL
AMPUL
AMPUL
5
6
7
8
INCREMENT, MG/L
0.110
0.132
0.882
0.772
LAB
ANALYST
NO.
NO.
101
1
0.1162
0. 1352
0.8902
0.8102
101
2
0.1142
0. 1382
0.9902
0.8502
102
3
0.1214
0.1314
0.9614
0.9114
106
1
0.1061
0.1311
0.6561
0.7711
106
2
0.1011
0.1311
0.6811
0.7811
106
3
0.1111
0.1311
0.8911
0.7611
107
3
0.1051
0.1341
0.9041
0.7941
107
4
0.109 1
0.1461
0.8941
0.7841
no
1
0.1201
0.2161
0.8840
0.8200
110
2
0.1321
0.2001
0.9600
0.8200
110
3
0.1131
0.0641
0.6421
0.6781
110
4
0.0841
0. 1011
0.692 1
0.7711
110
5
0.0921
0.1291
0.8000
0.7000
110
6
0.1141
0.1541
0.8051
0.7151
112
1 FW
0.1050
0.1450
0.8530
0.7710
112
1 EW
0.1210
0.1540
0.9640
0.8260
113
1
0.2510 R
0.3820
0.8160
0.9090
113
3
0.1390
0.1610
0.8780
0.7990
113
4
0.1198
0. 1678
1.0048
0.8098
114
1
0.1111
0.1311
0.9711
0.771 I
115
I
0.1426
0.1656
0.9446
0. 8646
1 16
1
0.1101
0.1291
0.8951
0.7931
117
1
0.2162R
0.2162
1 .0062
1 . 406 2 R
120
1
-0.1501
0.0166
0.7663
0.4144
121
1
0.0943
0.1333
0.8503
0.8373
122
1
0.1063
0. 1343
0.8273
0.7 153
123
1
0. 1222
0. 1482
0.8702
0.8602
123
2
0.1212
0.1312
0.8742
0.9182
125
4
0.0992
0.1312
0.8902
0.7002
126
2
0.1111
0. 1471
0.9581
0.6361
126
3
0.1272
0. 1482
1.407 1R
0.9661
127
2
0.0848
0.2088
0.8708
0.7808
130
I
0.1540
0. 1840
0.6690
0.6290
134
1
0.1053
0. 1503
0.7683
0.6603
FW =
FRESH WATER
EW =
ESTUARINE WATER
R = REJECTED
-------
54
APPENDIX 2
Summary of Data
-------
METHOD AND PERFORMANCE EVALUATION* AQCL, MQO
METHOD STUOY 2, NUTRIENTS
NITROGEN - AMMON I A, AMPUL 1
STATISTICS! ALL UATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY OF INCREMENT FROM DISTILLEO N A f ER
INCREMENT =
0.26
N
TRUE VAL.
MEAN
MEDIAN
ACCURACY
26 RANGE 0.40000
0.26 VARIANCE 0.00740
0.24961 STD. DEV. 0.08604
0.24500 CONF LIM. (95%) 0 16 86U
-8 00007 PERCENT, RELATIVE TO TRUE VALUE.
COEF. VAR. 0*34471
SKEWNESS 1.16502
NO. OF CELLS 6
RECOVERY OF INCREMENT
OATA IN
ASCEN01NG
ORDER
0. 11
0.14
0* 16
0. 16
0.16
0.19
0.20
0.20
HISTOGRAM
0.20
0.23
CELL MID.
FREQ,
0.23
0.24
0. 1100
2
XX
0.24
0. 1099
7
xxxxxxx
0.25
0.2699
13
xxxxxxxxxxx;
0.25
0.3499
2
XX
0.25
0.4299
1
X
0.26
0.5099
1
X
0.26
0.26
0.27
0.26
0.31
0.32
0.38
0.4L
0.51
METHOO ANO PERFORMANCE EVALUATION, AQCL, WJO
METHOD STUDY 2t NUTRIENTS
NITROGEN - AMMONIA, AMPUL 2
STATISTICS, ALL OATA, ALL LABORATORIES
MANUAL PROCEOURE
RECOVERY OF INCREMENT FROM DISTILLEO WATER
INCREMENT *
0.2 1
N
TRUE VAL.
MEAN
MEDIAN
ACCURACY
26
0.21
0,23769
0*21500
4.96 018
RANGE
VARIANCE
STO. DEV.
CONF. LIM.
0.32000
0.00617
0.07855
0.1 5396
COEF. VAR. 0.33047
5KEWN6SS 1.43663
NO. OF CELLS 6
PERCEN T f RELATIVE TO TRUE VALUE.
RECOVERY OF INCREMENT
OATA IN
ASCENDING
ORDER
0.13
0.15
0*15
0. 18
0.19
0. 19
0. 19
0.20
0.20
0.21
0.21
0.21
0.21
0.22
0.23
0.23
0.24
0.24
0.24
0.25
0.16
0.27
0.34
0.35
0.44
0.45
HI STOGRAM
MID.
FREU.
0.1300
3
XXX
0. 1940
t I
XXXXXXXXXXX
0.2580
8
XXXXXXXX
0.3219
2
XX
0.3859
0
0.4499
2
XX
-------
Mb T HOD AND PERFORMANCE EVALUATION AQCL, VA^O
HETHOO SFUOY & NUTRIENTS
NI t KObE N - AMMONIA, APPUL 3
STATISTICS* ALL DATA, ALL L A BORA T ORIb S
MANUAL PROCEDURE
RECOVERY OF INCREMENT FRCM UlSTILLED WATER
INCREMENT =
L 7 I
N
TRUE VAL.
ME AN
MEDIAN
ACCURACY
26
I .7 1
l.7!>961
I70000
RANGE
V AP1ANCE
STO. OEV.
CONF. LIM C95%>
0-68999
0-03647
0.19096
0 37432
COfcF. VAR 0.10853
SKEkNESS 1.13301
NO. OF CELLS 6
2.9013B PERCENT, RELATIVE TO TRUE VALUE.
RECOVERY OF 1 NCR E Mfc N T
DATA IN
ASCENDING
ORCER
1.54
1 . 55
1.36
1 .60
1.60
1.61
Ub2
1.66
HISTOGRAM
1.66
1 .66
CELL Ml C.
FREU.
1.66
1.69
1 .5400
5
xxxxx
1.69
1.6779
12
xxxxxxxxxxxx
1.71
.8 159
3
XXX
1.72
1 .9>39
2
XX
1.72
2.0919
3
XXX
1.73
2.2299
1
X
1.75
1.77
1 .7B
1.09
1 .90
2. 10
2.10
2.11
2.23
HEThOO ANO PERFORMANCE EVALUATION, AQCL, MQO
METHOD STUDY 2* NUTRIENTS
NITROGEN - AMMONIA, AMPUL A
STATISTICS, ALL OATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY OF INCREMENT FROM DISTILLED HATER
INCREMENT ° 1.92
0.14079
1.66525
6
" 26 RANGE 1.02000 COEF. VAR*
TRUE VAL. 1.92 VARIANCE 0.07664 SKEMNESS
MEAN 1.99192 STD. 06V. 0.28044 NO. OF CCLLS
MEDIAN 1.90000 CONF. LIM. C95%) 0 . 5^966
ACCURACY 3.745B9 PERCENT, RELATIVE TO TRUE VALUE.
RECUVERY OF INCREMENT
DATA [N
ASCENOING
ORDER
1 .66
1.73
1.76
1.60
1 .60
1 6 L
1.62
1.85
HISTOGRAM
1.86
1.88
CELL MID.
FREQ.
1 tie
1.69
1.6600
3
XXX
1.90
1 .8640
16
XXXXXXXXXXXXXXXX
1*90
2.0880
3
XXX
1 *90
2.2920
I
X
1.94
2.4960
0
1*96
2.7000
3
XXX
1.96
1.98
2.01
2. 10
2. 10
2.24
2.65
2.69
-------
METHOD AND PERFORMANCE EVALUATION, AQCL,WQO
METHOD STUOY 2, NUTRIENTS
NITROGEN - NITRATE, AMPUL i
STATISTICS, ALL OA T A » ALL LABORATORIES
MANUAL PROCEDURE
RECOVER* OP INCREMENT FROM DISTILLED WATER
INCREMENT = 0.16
0.21726
0.08573
6
N 28 RANGE 0.12000 COEF. VAR.
TRUE VAL. 0.16 VARIANCE 0.00088 SKEWNESS
MEAN 0.1371-4 STD. DEV. 0.02979 NO. OF CELLS
MEDIAN 0.14000 CCNF LIM. C95%) 0.05839
ACCURACY -14.28581 PERCENT, RELATIVE TO TRUE VALUE.
RECOVERY OF INCREMENT
data in
ASCENDING
ORDER
0.08
0.09
0* 10
0.10
0. 10
0. 11
0. 12
0 12
HISTOGRAM
0 12
0. 12
CELL MID.
FREO.
0. 12
0.13
0 .0800
2
XX
0. 14
0. 1040
4
xxxx
0. 14
0.1279
6
xxxxxx
0. 14
0.1519
13
xxxxxxxxxxxxx
0. 14
0. 1759
1
X
0. 14
0.1999
2
XX
0. 15
0. 15
0. 16
0.16
0.16
0. Lb
0.16
0.16
0.18
0.19
0.20
METHOD AND PERFORMANCE EVALUATION, AiCL, WOO
METHOD STUDY 2, NUTRIENTS
NITROGEN - NITRATE, AMPUL 2
STATISTICS, ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY OF INCREMENT FROM DISTULEO WATER
INCREMENT
« 0.19
N
28
RANGE 0.26999
TRUE VAL.
0. 19
VARIANCE 0.00262
MEAN
0. 18035
STD. DEV. 0.05124
MEDIAN
0.18000
CONF. LIM. (95%) 0 100*43
ACCURACY
-8. 7720*1
PERCENT, RELATIVE TO TRUE
COEF. VAR.
SKEWNESS
NO. OF CELLS
0.28411
1.54482
6
RECOVERY OF INCREMENT
DATA tN
ASCENDING
ORDER
0.10
0. 10
0. 12
0. 12
0.13
0. 14
0. 16
0. 16
HI STOGRAM
0. 16
0. 17
CELL MO.
FREU.
0. 17
0. 18
0. 1000
4
XXXX
0. 18
0. 1539
12
XXXXXXXXXXXX
0. 18
0.2079
10
XXXXXXXXXX
0. 10
0.2619
1
X
0. 18
0.3159
0
0. 19
0.3699
I
X
0. 19
0. |9
0. 19
0.20
0.20
0.20
0.21
0.22
0.22
0« 24
-------
MfcTHOD AND PFKFQRMANCE EVALUATION, AQCL, WQO
METHOD STUDY I, NUTRIENTS
NITROGEN - NITRATE, AMPUL 3
STATISTICS. ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY OF INCREMENT FROM DISTILLED WATER
INCREMENT = L *24
N 29 RANGE 0.79000 COEF. VAR. 0.1366*
TRUb VAL. I.24 VARlANCfc 0.0300L SKEWNESS 1.62445
MEAN 1.26792 STO. DEV. 0.17325 NO. OF CELLS 6
MEOIAN 1.23000 CONF LIM (95%) 0 3 3957
ACCURACY 0.95569 PERCENT, RELATIVE TO TRUE VALUE.
RECOVERY OF INCREMENT
DATA IN
ASCENDING
ORDER
1.08
1.08
1.10
1 . 10
I.10
1.13
L.16
Ul8 HISTOGRAM
1.19
1.20 CELL m10' FREQ.
1.21
1.21
1.23
1.23
1.24
1.25
1.26
1.28
1.30
1 .30
1.30
1.31
1.44
1 .46
I .47
1 .65
1.07
1.0600 6 XXXXXX
1,22 1.2360 18 XXXXXXXXXXXXXXXXXX
1.22
1.3960 3 XXX
1.5>40 0
1.7 20 1 X
1.8700 1 X
METHOD AND PERFORMANCE EVALUATION, AQCL , V*£)
METHOO STUOY 2, NUTRIENTS
NITROGEN - NITRATE, AMPUL 4
STATISTICS* ALL OATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY OF INCREMENT FROM OISTILLEO WATER
INCREMENT
1.00
N 29 RANGE 1.08999
TRUE VAL. 1.08 VARIANCE 0.04457
MEAN L.17241 STO. DEV. 0.21113
MEOIAN I.11000 CONF. LIM. C95%) 0.^1381
ACCURACY 6 5*1995 PERCENT, RELATIVE TO TRUE VALUE.
COEF. VAR.
SKEWNESS
NO. OF CELLS
0. 18008
2.31939
6
RECOVERY OF INCREMENT
DATA IN
ASCENDING
ORDER
0.92
0.97
0.98
1.00
1.00
1.03
1.04
1.06
HISTOGRAM
1.06
1.08
CELL MID.
FREQ.
1.10
1.10
0.9200
5
xxxxx
1.11
1.1380
18
XXXXXXXXXXXXXXXXXX
1.11
1.3559
4
xxxx
1.11
1.5739
1
X
1.12
1.7919
0
1.12
2.0099
I
X
1 .14
1 . 19
1.21
1.2 2
1.24
1.24
1.26
1.31
1.32
1.40
1.53
-------
McTHGD AND PERFORMANCE EVALUATION, AQCL, WQO
METHOD STUDY 2, NUTRIENfS
PMOSPHATL - SCL., orthc, ampul 1
STATISTICS, ALL DATA, ALL LABORATORIES
MANUAL PROCEOURE
RECOVERY OF INCREMENT FRCM DISTILLED HATER
INCREMENT = 0-029
0.40213
2.23827
6
N 29 RANGE 0.05999 COEF. VAR
TRUE VAL. 0.029 VARIANCE 0.00011 SKEHNESS
MEAN 0.02672 STD. DEV. 0.01074 NO. OF CELLS
MEOIAN 0.02600 CONF LIM C95%) 0 02105
ACCURACY -13 1774 0 PERCENT, RELATIVE TO TRUE VALUE.
RECOVERY OF INCREMENT
DATA IN
ascending
ORDER
0.010
O.OLO
0.017
0.019
0*019
0*020
o.on
0.0 1
HISTOGRAM
0.0 '2
0 . 0 5
CtLL MID.
FREU.
0.025
0.025
0.0100
2
XX
0.026
0.0219
14
xxxxxxxxxxxxxx
0.026
0.0339
11
xxxxxxxxxxx
0.026
0.0459
1
X
0.027
0.0579
0
0.028
0.0699
1
X
0.028
0.028
0.026
0.028
0.030
0.030
0.030
0.030
0.030
0.030
0.046
0.070
METhGC AND PERFORMANCE EVALUATION, ACCL , VQO
METHOD STUDY 2. NUTRIENTS
PHOSPHATE - SOL., ORTHO, AMPUL 2
STATISTICS, ALL OA T A ? ALL LABORATORIES
MANUAL PROCkOUKE
RECOVERY OF I NCR tHE N T FROM OISTlLLEO HATER
INCREMENT - 0.038
0.19753
0.31361
6
N 29 RANGE 0.03000 COEF. VAR.
TRUE VAL* 0.038 VARIANCE 0.00004 SKEWNESS
HEAN 0.03531 STD. OCV. 0.00697 NO. OF CELLS
MEOIAN 0.03600 CONF. LIM. C95%) 0.01366
ACCURACY -7.07813 PERCENT, RELATIVE TO TRUE VALUE.
RECOVERY OF INCREMENT
OA TA IN
ASCENDING
ORDER
0*020
0*020
0.024
0 . 028
0.030
0*030
0.031
0.032
H I stcgram
0.032
0.033
CELL mid.
FREC-
0.034
0.035
0.0200
2
0.035
0.0260
2
0.035
0.0319
7
0.036
0.0379
14
0.037
0.0439
2
0.037
0.0499
2
0*038
0 . 0 J 8
0.038
0.036
0.040
0.040
0.040
0.040
0*041
0.044
0.048
0.050
XX
XX
xxxxxxx
xxxxxxxxxxxxxx
XX
-------
KcfhOL AND PE^FLiRP&NCt EVALUATION, 4CCL, WQO
KtTHCO STUDY 2, NUTRIENTS
PHOSPHATE - SLL.t CrtThQ, AMPUL i
STATISTICS, ALL DATA, ALL LABORATf)RIES
NANOAL PROCEOLXE
RECUVEKY OF iNCRtMbNT FRC* DISTILLED WATER
INCREMENT = 0.363
COEF. VAft. 0.05106
SKfcUnlESS -1.3^700
NO. OF CELLS 6
value.
N RAMGE 0.09000
TitUE vAL. 0.333 VARIANCE 0.00036
M E A,j 0.37465 STD. DEV. 0.01913
MfcblAN 0.37800 CONF 1-IM (95%) 0 037^9
ACCURACY -1 57602 PERCENT, RFLATIVE TU TRUE
RtCbVERY (JF |MCKEME*T
DATA IN
ASCENDING
ORDER
0.310
0. 347
0. 350
0.352
0.3!>7
0.359
0.364
0. 365
HISTUGRAH
0.370
0. 372
CELL PIG.
FREC.
0. 374
0.375
G.3'00
t
X
0. J76
0.3 80
0
0. 377
0.3^60
3
XXX
0. 376
0. 3640
0
XXXXXX
0. 380
0.3820
14
XXXXXXXXXXXXXX
0. 380
0.4000
5
xxxxx
0. 380
0. 383
0. 363
0.384
0. 386
0. 390
0.390
0.392
0. 393
0. 398
0.400
0.400
Mfc ThOC AND PERFORMANCE EVALUAIICN, AQCL , WQO
METHOD STUOY 2, NUTRIFNTS
9-
O
PHOSPHATt - SOL., ORTHO, AHPUL 4
STATISTICS, ALL DATA,
MANUAL PROCfcDUkE
RECOVERY OF INCREMENT
ALL LABORATORIES
FRC* DISTILLED MATER
INCREMENT = 0.335
N 29 RANGE 0.06000
TKUE VAL. 0.335 VARIANCE 0.00018
Mb AN 0.33089 STD. OEV. 0.01359
MEOIAN 0.33000 CONF. LIM C95%) 0. 02664
ACCURACY -1.22504 PERCENT, RELATIVE TO TRUE VALUE
COEF. V AR * 0.04107
SKEWNESS 0*08756
NO. OF CELLS 6
KECUVERY UF INCREMENT
DATA IN
ASCENDING
ORDER
0. 3C0
0. 310
0.310
0. 320
0.320
0.320
0.320
0. 320
HISTOGRAM
0.320
0. 330
ChLL HID.
FREO.
0.3 30
0.330
0.3000
1
0.330
0.3119
2
0. 3 30
0.3239
6
0. 330
0.3359
16
0. 332
0.3479
2
0. 332
0.3599
2
0. 332
0. 332
0, 336
0.340
0. 340
0.340
0.340
0.340
0. 342
0. 350
0.360
0* 360
X
XX
XXXXXX
XXXXXXXXXXXXXXXX
XX
-------
METHOD AND PERFORMANCE EVALUATION, AQCL, WQO
METHOO STUDY 2f NUTRIENTS
NITROGEN - KJElO.v TCT AMPUL 5
STATISTICS. ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY OF INCREMENT FROM DISTILLED WATER
INCREMENT = 0.31
0-56265
0.51305
6
N 33 RANGE 0.77999 COEF. VAR.
TRUE VAL. 0.31 VARIANCE 0.04644 SKEWNESS
MEAN 0.38302 STD. DEV. 0.21551 NO. OF CELLS
MEDIAN 0.34000 CONF. LIM. (95%) 0 22*10
ACCURACY 23.55806 PERCENT, RELATIVE TO TRUE VALUE.
RECOVERY OF INCREMENT
DATA IN
ASCENDING
OROER
0.04
0.10
0.10
0.14
0.14
0.16
0.16
0.19 HISTOGRAM
0.21
C .28 CELL MID. FK6Q.
( .30
i.30 0.0400 3 XXX
0.31 0.1959 6 XXXXXX
0.32 0.3519 13 XXXXXXXXXXXXX
0.32 0.5079 4 XXXX
0.32 0.6639 3 XXX
0.34 0.8199 4 XXXX
0.35
0.35
0.41
0.41
0.42
0.44
0.47
0.54
0.*4
0.59
0.61
0.62
0. 76
0.78
0.80
0.82
METHOD AND PERFORMANCE EVALUATION, AQCL, WQO
METHOD STUOY 2* NUTRIENTS
NITROGEN - KJELO.* TCT., AMPUL 6
STATISTICS* ALL DATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY OF INCREMENT FRUM DISTILLED WATER
INCREMENT * 0.20
N 33 RANGE 0.61000 COEF. VAR. 0.58907
TRUE VAL. 0.20 VARIANCE 0.02373 SKEWNESS 0.34918
MEAN 0.26151 STO. DEV. 0.15405 NO. OF CELLS 6
MED I AN 0.24000 CONF LIM. C95%) 0.30194
ACCURACY 30.75743 PERCENT» RELATIVE TO TRUE VALUE.
RECOVERY OF INCREMENT
OATA IN
ASCENDING
OROER
0.00
0.02
0.05
0.06
0. 10
0. 10
0.10
0. 10
HISTOGRAM
0. 19
0. 19
CELL MID.
FREQ.
0.20
0.22
0.0000
4
XXXX
0.22
0.1219
4
XXXX
0.23
0.2439
14
XXXXXXXXXXXXXX
0.23
0.3659
5
xxxxx
0.23
0.4879
4
XXXX
0.24
0.6100
.2
XX
0.24
0.25
0.29
0.29
0.30
0.32
0.33
0.34
0.40
0.40
0.43
0.43
0.45
O.bO
0.57
-------
MeTHGC fiNU PERFORPii/^CE EVALUATION, AGCL , WQO
METHOD STUDY 2, NUTRIENTS
NlTKUGEN - KJfcLO.* TCT, AMPUL 7
STATISTICS* ALL DATA, ALL L ABOK A TOR I6S
MANUAL proceoure
RECUVERY OF INCREMENT FROM DISTILLED WATER
INCREMENT = A.10
0. 30464
0.96105
6
N 34 RANGfc 6.13000 CGEF. VAR.
TkUt VAL. 4.10 VARIANCE 1.42717 SKEHNESS
KEA.-l 3.92146 STO. DEV. 1.19464 NO. OF CELLS
h£D I AN 4.07000 CONF LIM. C95%) 2.3^119
ACCURACY -1.45591 PERCENT * RELATIVE TO TRUE VALUE.
RECOVERY OF INCREMENT
OATA IN
ASCENDING
OROER
0.03
2.10
2.16
2.36
2.45
2.75
2.90
2.90
histogram
3.76
3.78
CELL MID.
FREQ.
3.84
3.97
0.0300
1
X
4.00
I .2560
0
4.00
2.4819
7
XXXXXXX
4.01
3."079
16
XXKXXXXXXXXXXXXX
4.02
4340
6
XXXXXXXX
4.06
6.1599
2
XX
4.06
4. 12
4.20
4.20
4.22
4.26
4.30
4.35
4.42
4.47
4.60
4.95
5.23
5.30
5.44
5. 74
6. 16
METHOD AND PERFORMANCE EVALUATION ACCl, WQO
METHOD STUDY 2, NUTRIENTS
NITROGEN - KJELO.» TOT., AMPUL 8
STATISTICS, ALL OATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY OF INCREMENT FRCM DISTILLEO WATER
INCREMENT = 4.61
0*31434
0.75609
6
N 33 RANGE 7.09000 COEF. VAR.
TRUE VAL. 4.61 VARIANCE 1.88833 SKEHNESS
MEAN 4.3715L STO. 0EV.r 1.37416 NO. OF CELLS
MEDIAN 4.60000 CCNF. LIM. C95%) 2*69335
ACCURACY - 2.2 77 77 PERCENT, RELATIVE TO TRUE VALUE.
RECUVERY OF INCREMENT
OATA IN
ASCENOING
ORDER
0.10
2.29
2.35
2.56
2.56
2.95
3.40
3.50 HISTOGRAM
4.08
4.44 CELL HID. FREG*
4.50
4.50 0.1000 1 X
4.50 1.5179 0
4.55 2.9359 7 XXXXXXX
A.57 4.3540 20 XXXXXXXXXXXXXXXXXXXX
4.56 5.7719 3 XXX
4.60 7.189S 2 XX
4.66
4.68
4. 70
4.71
4. 72
4.72
4.72
4.80
4.80
4.90
5.00
5.45
6. 10
6.26
6.74
-------
ME P-iOD ANO PERFORMANCE EVALUATION, ACCL , WQO
METHOD STUDY 2, NUTRIENTS
PHOSPHORUS - TOTAL, AMPUL 5
STATISTICS, ALL OA T A » ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY OF INCREMENT FROM DISTILLED WATER
INCREMENT = 0,110
0.13314
0*68 862
6
N 35 RANGE 0.06399 COEF. VAR.
TftUf VAL - 0.110 VARIANCE 0.00022 SKEWNESS
MEAN 0.11262 STO. OEV. 0.01*99 NO. OF CELLS
MEDIAN 0,11000 CONF. L1M. C95%) 0.02938
ACCURACY 0. 6059U PERCENT, RELATIVE TO TRUE VALUE.
RECOVERY OF INCREMENT
DATA IN
ASCENDING
OROER
0.066
0.090
0.090
0.096
0.096
0. 100
0. 100
0. 100
0. 102
0- 107
0. 1C8
0. If 8
0. I< 8
0. 1
-------
METHOD AND PERFORMANCE EVALUATION, AQCL, WQO
METHOD STUDY 2, MjTfUENTS
PHOSPHORUS - TOTAL, AMPUL 7
STATISTICS, all data, all laboratories
MANUAL PROCEDURE
RECOVERY OF INCREMENT PRC* OISTILLFO WATER
INCREMENT = 0.882
COEF. VAR. 0,13895
SKEHNESS -1.44883
NO. OF CELLS 6
VALUE.
N 36 RANGE 0.64199
TKUC VAL. 0*882 VARIANCE 0.01397
ME Am 0.85080 STD. DEV. 0.11822
MEOI Ah 0.88000 CONF LIM. C95%) 0 20171
ACCURACY -2.51507 PERCENT, R fcL AT IV E TC TRUE
KECUVERY OF INCREMENT
OATA IN
ASCENDING
ORDER
0.452
0.597
0.606
0.665
0. 706
0.300
0.800
0.825
0.829
HISTOGRAM
0;833 CELL KID. FREQ
0.840
0.840
0.850
0.855
0.855
0.863
0.876
0.8d0
0.880
0.864
0.890
0.892
0.893
0.900
0.908
0.909
0.911
0.920
0.920
0.923
0.925
0.940
0.940
0.940
0.968
1*094
0.4520
L
X
0.5b03
I
XX
0.7007
2
XX
0.8371
19
Xy ,W AAXXXXXXXXXXXX
0.9 ,55
I 1
xxxxxxxxxxx
1.0 >39
I
X
METHOD ANO PERFORMANCE EVALUATION, AQCL , WQO
METHOD STUDY 2, NUTRIENTS
PHOSPHORUS - TOTAL, AMPUL fl
STATISTICS, ALL OATA, ALL LABORATORIES
MANUAL PROCEDURE
RECOVERY OF INCREMENT FROM DISTILLEO MATER
INCREMENT a 0.772
N 35 RANGE 0.33600 COEF. VAR. 0.08377
IRUE VAL. 0.772 VARIANCE 0.00426 5KEWNESS 0.17784
MtAN 0.77971 STD. DEV. 0.06532 NO. OF CELLS 6
MfcOIAN 0.78000 CONF. LIM. C95%) 0.12803
ACCURACY O.iJ04l6 PERCENT, RELATIVE TO TRUE VALUE
RECOVERY OF INCREMENT
DATA IN
ASCENDING
ORDER
0.625
0.654
0.678
0.685
0.720
0.735
0.747
0.750
HI STOGRAM
0.750
0. 750
CELL H10.
FREC.
0. 758
0. 760
0.6^50
2
XX
0.760
0.6922
3
XXX
0.760
0.7594
1 7
XXXXXXXXXXXXXXXXX
0.770
0.6265
9
XXXXXXXXX
0.775
0.8937
3
XXX
0.778
0.9609
I
X
0.780
0.783
0. 788
0.790
0.790
0.799
o.aoo
0.800
0*607
0.810
0*810
0.810
0.820
0.840
0.870
0.683
0.894
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