United States
Environmental Protection
Agency
Municipal Environmental Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-81-046 May 1981
Project Summary
Analytical Methods
Evaluation for Applicability in
Leachate Analysis
Foppe B. DeWalle, Theodore Zeisig, John F. C. Sung, Donald M. Norman, Jack
B. Hatlen, Edward S. K. Chian, Michael G. Bissel, Kim Hayes, and Donald E.
Sanning
Thirty-two laboratories in the United
States and Canada conducted round-
robin analyses of leachate samples.
Samples were analyzed for up to 28
parameters to evaluate accuracy and
precision of the methods employed.
The 28 parameters included physical
parameters (pH, oxidation reduction
potential, conductivity, turbidity, and
solids), organics (chemical oxygen
demand, total organic carbon, organic
nitrogen, and free volatile fatty acids),
anions (sulfate, phosphate, chloride,
nitrate, and bicarbonate), and cations
(alkali metals, alkaline earth metals,
transition metals, and heavy metals).
Individual parameter coefficients of
variation ranged from 32 percent to
210 percent. Significant differences
were noted between results from
colorimetric methods and from titri-
metric and physical methods. The
average recovery for spiked parameters
varied widely for individual parameters.
The most applicable method for
analysis of each parameter is recom-
mended. Use of the standard addition
technique is required in each laboratory
to determine the matrix depression or
enhancement for each type of leachate
sample.
The accuracy (i.e., agreement be-
tween measured and actual amounts)
and the precision (i.e., reproducibility)
of different analytical methods were
evaluated in depth. Thirty-two labora-
tories submitted final analytical
results.
This Project Summary was developed
by EPA's Municipal Environmental
Research Laboratory, Cincinnati, OH,
to announce key findings of the re-
search project that is fully documented
in a separate report of the same title
(see Project Report ordering informa-
tion at back).
Technical Discussion
Leachate samples were collected
from nine locations chosen to represent
different climatic conditions, varying
site age, and a wide range of chemical
oxygen demand (COD). Adoublequantity
of leachate was collected from one of
the sites so that a spiked sample could
also be analyzed. Therefore, the nine
sites provided ten leachate samples.
The leachate samples were collected,
chilled, anaerobically sorted, and im-
mediately shipped by air to Stanford
University. At Stanford, each sample
was emptied anaerobically into a 150-
liter vessel, thoroughly mixed, placed in
55 one-liter glass containers and 110
five-hundred-mi polyethylene containers,
and chilled for distribution by air freight
to the participating laboratories. After
complete mixing of the double-quantity
sample, half of the sample was spiked
with each of the chemical parameters to
a concentration of about 25 percent of
the original concentration in the un-
spiked sample.
The participating laboratories recorded
analytical information on a Stanford
Reporting Form that was manually
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edited before key punching. All major
computations and data file management
were performed on the Control Data
Cyber 173 and CDC 6400 dual mam-
frame system of the Academic Computer
Center at the University of Washington.
The leachate data base was maintained
on disc and magnetic tape files. Most of
the data preprocessing programs used
for data sorting and the computation of
sample statistics were written in
FORTRAN, compiled with the University
of Minnesota Fortran compiler (Version
5.1), and executed under the CDC
NOS/BE (Version 1.2) operating
system. The statistical package Minitab
II was used extensively in the statistical
analysis and plotting of the leachate
data. The report concentration levels
were processed with a G12.5 format
specification for all 28 parameters. A
G13.6 format specification was used for
the average and standard deviation
computed for the concentration levels.
The data from each parameter were
analyzed using the following approach.
The within- and between-laboratory
standard deviations were plotted against
the concentration level to determine if a
transformation of the data was required
to make the variability at different levels
of the parameter approximately equal.
Quantile-quantile plots were then con-
structed for the original and transformed
data and used to determine if the distri-
butions of the original or the transformed
data were reasonably close to a normal
distribution. To determine if systematic
differences exist between the analytical
methods used and between laboratories,
a ranking procedure was used. Finally,
the analysis of variance was used to
estimate the between-laboratory, labo-
ratory-sample-interaction, and within-
laboratory variance components.
A statistical evaluation of the data
revealed that the overall coefficient of
variation (i.e., the standard deviation as
a percentage of the average) ranged
from 32 percent for the COD determina-
tion to 210 percent for the cadmium
determination. The between-laboratory
component of variation was larger than
the within-laboratory component. The
largest portion of the variation, however,
was due to a sample laboratory inter-
action (i.e., the laboratories' relative
results change for different leachate
samples).
Further, the results of the leachate
analysis more closely resembled a
lognormal distribution than a normal
distribution. The standard deviation of
the data in the lognormal scale is
equivalent to the coefficient of variation
of the data in the original scale of
measurement as calculated through a
first order Taylor expansion. The standard
deviations for the different parameters/
variables are shown in Table 1. The
overall standard deviation <7R is approxi-
mately 1.5 times larger than the be-
Table 1. Standard Deviations for All Reporting Laboratories and for Those Reporting Three Replicates
Parameter/
Variable
pH
ORP
Turbidity
Conductivity
Volatile Acids
COD
TOO
Total Residue
Volatile Residue
Organic Nitrogen
Ammonia Nitrogen
Sulfate
Total Phosphorus
Chloride
Alkalinity
Nitrate Nitrogen
Sodium
Potassium
Calcium
Magnesium
Barium
Iron
Zinc
Lead
Chromium
Cadmium
Copper
Nickel
All Reporting
O-R
0.349
123
2.01
0.464
1.01
0.324
0.602
0.574
0.764
1.5O
0.89
1.80
1.45
0.923
0.380
1.98
0.545
0.661
0.74
0.594
1.41
0.532
1.35
0.962
1.71
2.16
1.42
1.08
Laboratories
O-L
0.152
93
1.47
0.225
0.627
0.20
0.294
0.517
0.638
1.02
0.923
0.603
1.20
0.494
0.222
1.50
0.125
0.388
0.642
0.109
1.05
0.281
1.03
0.648
1.32
1.78
1.14
0.732
Labs Reporting
Three Replicates
O-LS
0.1 08
68
1.09
0.174
0.855
0.212
0.493
0.185
0.45
0.671
0.69
1.47
0.610
0.80
0.358
1.32
0.578
0.438
0.336
0.676
1.19
0.354
0.797
0.644
0.727
0.440
0.832
0.842
<7w
0.052
30
0.114
0.026
0.151
0.066
0.069
0.062
0.172
0.265
0.110
0.774
0.563
0.055
0.033
0.193
0.037
0.056
0.046
0.036
0.043
0.053
0.103
0.308
0.665
1.04
0.251
0.365
O-R -Overall standard deviation.
CTL = Between laboratory standard deviation.
ois = Laboratory sample interaction standard deviation.
CT\N = Standard deviation within laboratories.
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tween-laboratory standard deviation
component a\_. The overall standard
deviation was especially large for the
analysis of cadmium, nitrate nitrogen,
turbidity, sulfate, chromium, organic
nitrogen, copper, zinc, and barium.
Since leachate differs from water and
wastewater in both content and con-
centration, interferences can lead to
erroneous results when water and
wastewater methods are used for
leachate analyses. Table 2 shows the
percent variance associated with the
following water/wastewater methods:
(1) EPA Methods for Chemical Analysis
of Water and Wastes (1974); (2) ASTM
Part 31: Water (1975); and (3) Standard
Methods (1971).
Substantial differences existed be-
tween different analytical methods,
especially between manual and auto-
mated methods. Colorimetric methods
tended to give values that were some-
times different from those of physical
methods. Differences likewise existed
among instrumental methods. Pretesting
of storage time indicated that no time
effect existed to produce a variation in
the analytical results, nor did the partic-
ular dilutions have a major effect on the
Table 2. Percent of Variance Ranges for Three Methods Used to Analyze Water and Wastewater
Parameter/
Variance
pH
OfiP
Turbidity
Conductivity
Volatile Acids
COD
TOO
Total Residue
Volatile Residue
Organic Nitrogen
Ammonia Nitrogen
Sulfate
Total Phosphorus
Chloride
Alkalinity
Nitrate Nitrogen
Sodium
Potassium
Calcium
Magnesium
Barium
Iron
Zinc
Lead
Chromium
Cadmium
Copper
Nickel
Method
Electrometric
Electrometric
Photometric
Electrometric
Chromatographic
Manual reflux
IR detection
Gravimetric
Gravimetric
Kjeldahl N
Automated Phenate
Distillation
Selected Ion Electrodes
Automated Phenate
Direct Nesslerization
Direct Phenate
Turbidimetric
Automated Chloranilate
Gravimetric
Automated Ascorbic Acid
Manual Ascorbic Acid
Mercuric Nitrate
Ferricyanide
Argentometric
Potenti
Automated Cadmium Reduction
Manual Cadmium Reduction
Brucine
Flame Photometric
Direct A. A.
Flame Photometric
Direct A.A.
EDTA Titri metric
Direct A.A.
Direct A.A.
Direct A.A.
Direct A.A.
Phenanthroline
-
-
-
-
-
-
EPA
(1974)
a
(%)
1.6-3.1
—
1.6-26
7-8.2
—
6.58
80-7.8
-
-
99-26
24.6-31.8
58-14.5
3.8-2.2
0.35-1.1
-
-
26.7-5.9
0.3-1.5
-
47.2-22
30-14.5
9.06-2.96
-
-
15.8-4.0
4.1-26.3
-
57.5-17.3
-
1.5
-
10.3-10.2
-
0.3-0.6
4.76-2.5
10.8-6.5
609-21
-
314-34.5
114-33
105-28.4
350-23
81-17
5.5-0.8
ASTM
(1975)
a
(%)
a
5-10 mV
—
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Table 3. Recommended Methods for Leachate Analysis
Leachate Parameter
Recommended Method
pH
Oxidation reduction potential
Turbidity
Conductivity
Free volatile fatty acids
Chemical oxygen demand
Total residue
Volatile residue
Organic nitrogen
Ammonia nitrogen
Sulfate
Total phosphorus
Chloride
Alkalinity
Nitrate
Sodium and Potassium
Calcium, Magnesium, Barium
Heavy metals (Fe, In, Pb, Cr,
Cd, Cu, Ni)
Electrometric method on fresh sample, using glass electrode and temperature correction.
Electrometric method on fresh sample, using platinum electrode with the calomel reference
electrode.
Nephelometric method on a fresh sample.
Electrometric method using platinum electrode and temperature correction.
Chromatographic method. COD determination should also be conducted.
Manual dichromatic reflux method using the ferrous ammonium sulfate titration.
Drying method at 104°C.
Drying at 550°C without prior filtration of sample.
Kjeldahl manual titration.
Distillation tritration method.
Gravimetric method.
Ascorbic acid method using the persulfate digestion step.
Potentiometric titration.
Potentiometric method with titration to inflection point of about pH 4.5.
Cadmium reduction method after separate determination of the nitrite ion.
Atomic absorption or manual flame or automated flame emission method.
Atomic absorption spectrophotometric.
Direct aspiration atomic absorption spectrophotometric method.
outcome of the analysis. However,
concentration ranges of a leachate con-
stituent can produce a major effect on
the analysis. This concentration effect
was found to be particularly evident in
spiked samples (i.e., the recovery rates
varied widely for individual parameters).
From this study, the authors recom-
mend preferred methods for leachate
analyses (Table 3), and general reasons
are given for selecting a particular
analytical method as being the most
applicable.
This report was submitted in fulfill-
ment of Grant R805753 by the University
of Washington, Department of Environ-
mental Health, and of Grant R804883
by Stanford University, Department of
Civil Engineering, under sponsorship of
the U.S. Environmental Protection
Agency.
Foppe B. DeWalle, Theodore Zeisig, John F. C. Sung, Donald M. Norman, and
Jack B. Halien are with the University of Washington, Seattle, WA 98195;
Michael G. Bissel and Kim Hayes are with Stanford University, Stanford, CA
96205.
Donald E. Banning is the EPA Project Officer (see below).
The complete report, entitled "Analytical Methods Evaluation for Applicability
in Leachate Analysis," (Order No. PB 81-172 306; Cost: $24.50, subject to
change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Municipal Environmental Research Laboratory
U. S. Environmental Protection Agency
Cincinnati, OH 45268
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300
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