United States
Environmental Protection
Agency
Environmental Monitoring
Systems Laboratory
Las Vegas NV 89193
Research and Development
EPA/600/S8-87/038 Jan. 1988
AEPA Project Summary
National Surface Water Survey:
Western Lake Survey (Phase
l-Synoptic Chemistry) Analytical
Methods Manual
H. B. Kerfoot and M. L Faber
The National Surface Water Survey
component of the National Acid Precipi-
tation Assessment Program is designed
to evaluate the present water chemistry
of lakes and streams, to determine the
status of certain biotic resources, and
to select regionally representative sur-
face waters for a long-term monitoring
program that will study changes in
aquatic resources. The Eastern Lake
Survey Phase I and the Western Lake
Survey Phase I are parts of the
National Surface Water Survey.
The Analytical Methods Manual for
the Western Lake Survey Phase I is a
supplement to the Analytical Methods
Manual for the Eastern Lake Survey
Phase I. This supplement provides a
general description of the methods that
are used by the field laboratories and by
the analytical laboratories; a detailed
description of the analytical methods
appears in the Analytical Methods
Manual for the Eastern Lake Survey
Phase I. The supplement also describes
new and modified sample processing
procedures that were developed specifi-
cally for the West.
This Project Summary was developed
by EPA't Environmental Monitoring
Systems Laboratory, Las Vegas, NV, to
announce key findings of the research
project that Is fully documented In a
separate report of the same title (see
Project Report ordering Information at
back).
Introduction
Western Lake Survey Phase I
The National Acid Precipitation Assess-
ment Program (NAPAP) was initiated at
the request of the Administrator of the
U.S. Environmental Protection Agency
(EPA) to evaluate the extent of the effects
of acidic deposition on aquatic resources
within the United States. When it became
apparent that existing data could not be
used to assess quantitatively the present
chemical and biological status of U.S.
surface waters, the National Surface
Water Survey (NSWS) program was in-
corporated as part of NAPAP to obtain
that information. The National Lake
Survey (NLS) component of NSWS com-
prises Phase I Eastern Lake Survey
(ELS-I), Phase I Western Lake Survey
(WLS-I), and Phase II Temporal
Variability.
ELS-I, a synoptic survey of the chem-
istry of 1,612 representative lakes in the
Southeast, Northeast, and Upper Midwest,
was conducted to obtain a regional and
national data base of water-quality pa-
rameters that are pertinent to evaluating
the effects of acidic deposition.
Parallel to ELS-I, the WLS-I portion of
NSWS is a synoptic survey of 757 lakes
in the West. WLS-I sampling is conducted
during fall overturn when chemical vari-
ability within a lake is expected to be
minimal as a result of circulation within
the water column. The analytes and
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physical parameters that will be measured
during WLS-I are listed in Table 1, along
with the data quality objectives for the
survey.
For designated regions of the West,
WLS-I is designed (1) to determine the
percentage (by number and area) and
location of lakes that are potentially
susceptible to change as a result of acidic
deposition and that have low acid-
neutralizing capacity (ANC): (2) to in-
vestigate the relationships among water
Table 1. Analytes, Physical Parameters, and Data Quality Objectives, Western Lake Survey Phase I (after Drouse et al., 1986)
Site8
2.3
2,3
3
3
3
3
1.3
2,3
3
3
3
3
3
3
3
3
3
1.2
3
3
3
3
2
2
Parameter11
Al, Extractable
Al. Total
ANC
BNC
Ca
Cl
Conductance
DIC
DOC
F-. Total
dissolved
Fe
K
Mg
Mn
Na
NH4+
N03
pH, Field
pH, Analytical
laboratory
P. Total
SiO2
S042
True color
Turbidity
Method
Extraction with 8-
hydroxyquinoline into
methyl isobutyl ketone
followed byAA" (furnace)
AAe (furnace)
Titration and Gran
analysis
Titration and Gran
analysis
AA" (flame) or ICF>9
Ion chromatography
Conductivity cell and
meter
Instrumental (acidi-
fication, CO2 generation.
IR detection)
Instrumental (UV-
promoted oxidation. CO2
generation, IR detection)
Ion-selective electrode
and meter
AAe (flame) or ICP9
AAe (flame)
AAe (flame) or ICf*
AA" (flame) or ICP*
AA" (flame)
Automated color imetry
(phenate)
Ion chromatography
pH electrode and meter
pH electrode and meter
Automated colorimetry
(phosphomolybdate)
Automated colorimetry
(molybdate blue)
Ion chromatography
Comparison to platinum-
cobalt color standards
Instrument
(nephelometer)
Unit of
Measure
mg/L
mg/L
neq/L
lueq/L
mg/L
mg/L
liS/cm
mg/L
mg/L
Expected
Rangec
0.005
O.O05
-too
-10
0.5
O.2
5
0.05
0.1
1.0
- 1.0
- 1,000
- 150
- 20
- 10
- 1.OOO
- 15
- 50
Required
Detection
Limits
O.O05
0.005
f
i
0.01
0.01
h
0.05
0.1
Precision
(Relative Standard Deviation
[RSD] Upper Limit (%V
10(Alconc.
20 (Al cone.
10 (Al cone.
20 (Al cone.
10
10
5
5
2
10
>0.01 mg/L)
O.01 mg/L)
<0.0/ mg/L)
5 (DOC cone. >5 mg/L)
Accuracy
(Max.
Absolute
Bias (%])
10
20
10
20
10
1O
10
10
5
10
10
10 (DOC cone. <5 mg/L)
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
pH units
pH units
mg/L
0.01
0.01
0.1
0.1
0.01
0.5
0.01
0.01
3
3
0.005
- 0.2
- 5
- 1
- 7
- 5
- 7
- 2
- 5
- 8
- 8
- 0.07
0.005
o.or
O.01
0.01
0.01
0.01
0.01
0.005
0.002
5
10
5
5
JO
5
5
10
±0.1'
±0.05'
10 (P cone. >O.01 mg/L)
20 (P cone.
NTU*
0.200
1
0
2
- 25
- 20
- 200
- 15
0.05
0.05
0
2
5
5
±5'
10
10
10
10
10
10
1O
10
to
±0.1'
±0.05'
10
20
10
10
10
a 1 - lake site, 2 = field laboratory, 3 - analytical laboratory.
b Dissolved ions and metals are being determined, except where noted.
c Ranges are for lake waters.
d Unless otherwise noted, this is the %RSD at concentrations greater than 10 times the required detection limit.
8 AA = atomic absorption spectroscopy.
' Absolute blank value must be<10 peq/L
9 ICP - inductively coupled plasma atomic emission spectroscopy.
h Blank must be
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chemistry, regional acidic deposition
patterns, land use, physiographic features,
lake morphology, and basin geometry
within and among regions; and (3) to
identify smaller subsets of representative
lakes for more intensive sampling in
future surveys.
Of the lakes to be sampled during
WLS-I, 455 lie within designated wilder-
ness areas. In order to observe the guide-
lines and regulations set forth in the
Wilderness Act, almost all lakes located
within wilderness areas that have been
selected for sampling must be sampled
by ground crews of the U.S. Department
of Agriculture Forest Service. The
ground crews travel to lakes on foot or on
horseback. The lakes that are not in
wilderness areas are sampled by heli-
copter crews under the direction of EPA.
Selected wilderness-area lakes that are
inaccessible by ground crews are sampled
by helicopter crews during periods when
disturbance to wildlife and to hikers is
minimal. In addition, 45 wilderness-area
lakes are sampled by ground crews and
by helicopter crews. The results for
samples collected from these 45 calibra-
tion lakes will be used to evaluate the
comparability of ground crew and heli-
copter crew protocols for collecting and
handling water samples. Data derived
from the chemical analyses conducted
during this calibration study will be used
to establish calibration factors that can
be applied to analytical values reported
for all WLS-I samples. The calibration
factors are intended to eliminate value
differences that result from variations in
sampling protocol, sample holding time,
or laboratory bias.
Two other studies are being conducted
as part of WLS-I. The purpose of one
study, the nitrate-sulfate stability study,
is to compare sample preservation
methods and to study the effects of hold-
ing samples for different lengths of time
before preserving them. The purpose of
the second study, the Corvallis study, is
to compare results for splits of the same
sample when the splits have been
analyzed by different methods. Both
studies can provide checks on sampling,
processing, and analytical performance.
Related Documents
This WLS-I Analytical Methods Manual
is a supplement to the ELS-f Analytical
Methods Manual (Hillman et al., 1986).
This supplement discusses in detail the
field laboratory procedures that were not
used during ELS-I. It provides a general
description of the WLS-I field laboratory
methods that were also used during ELS-
I, and it gives a general description of the
analytical laboratory methods. Because
the analytical methods were identical for
ELS-I and WLS-I, the supplement provides
only a general discussion of the analytes
and physical parameters studied. Descrip-
tions of the WLS-I sample collection and
processing methods are given in Bonoff
and Groeger (1987). The WLS-I Quality
Assurance (QA) Plan is presented in
Silverstein et al. (1987), a document that
is based on concepts originally presented
in Drouse1 etal. (1986).
Field Laboratory Operations
In general, WLS-I field laboratory
operations parallel ELS-I field laboratory
operations; however, WLS-I employs two
sampling methods (sampling from heli-
copters and sampling from boats) that
require some differences in sample
processing.
Routine Operations
Field laboratory operations are based
at fully equipped laboratory trailers. The
five field laboratory trailers, one stationed
at each WLS-I field base, provide facilities
for sample receipt, analysis, and preser-
vation, and for aliquot preparation and
shipping. Lake samples, blank samples,
and duplicate samples, which are col-
lected and labeled by the sampling crews,
are delivered to the field laboratory for
preliminary analysis and processing.
Samples are filtered, preserved, and
divided into aliquots (see Table 2). Natural
and synthetic audit samples are added to
the batches at the field laboratory, and
the completed batches are shipped by
overnight courier from the field laboratory
to analytical laboratories that perform
detailed sample analyses. Split samples
(collected from the Van Dorn sampler by
the ground crews only) are preserved
with HgCI2 at the lake site before they are
delivered to the field laboratory. These
unfiltered, split samples are labeled and
are shipped to the EPA Environmental
Monitoring Systems Laboratory in Las
Vegas, Nevada (EMSL-LV), for use in the
nitrate-sulfate study. (This type of split
sample was not collected during ELS-I.)
In addition, the field laboratory prepares
the split samples for shipment to the EPA
Environmental Research Laboratory in
Corvallis, Oregon (ERL-C). These splits
are filtered, then they are preserved with
HN03. At ERL-C, the splits are analyzed
by inductively coupled plasma atomic
emission spectroscopy. The field labora-
tory also serves as the distribution center
for water used to prepare blank samples,
for conductivity standards used to perform
Hydrolab calibration, and for supplies used
at the lake sites.
Overall administration of the field
laboratory is the responsibility of the field
laboratory coordinator. Supplies for the
ground crew are provided through the
field laboratory coordinator by the logistics
coordinator. (The position of logistics
coordinator was created for WLS-I.) The
Table 2.
Aliquot
Aliquots, Containers, Preservatives, and Corresponding Analyses Measured,
Western Lake Survey Phase I
Container
Volume
Preservative and
Description
Analyses
1
250 mL Filtered, preserved with HNO3topH<2 Ca, Fe. K, Mg, Mn, Na
10 mL
Filtered, preserved with hydroxyquinoline
extract
4
5
6
7
250 mL Filtered, no preservative
125 mL Filtered, preserved with H2SO4 to pH <2
500 mL Unfiltered, no preservative
Extractable Al
CI-. NO3: S/Oj, SO/', total
dissolved F~
DOC, NHf*
ANC. BNC, DIG. pH.
conductance
J25mL Unfiltered. preserved with H2SO4 to pH<2 Total P
125 mL Unfiltered, preserved with HN03 to pH<2 Total Al
EMSL-LV
Splits 125 mL Unfiltered, preserved with 0.1 mL HgCI2
ERL-C
Splits
125 mL Filtered, preserved with HNO3 to pH <2
NO3; SO/
Ca, Fe. K. Mg. Mn. Na. SiO*
SO,2' tqtalAI. total P
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laboratory supervisor, who is responsible
for managing daily laboratory operations,
performs dissolved inorganic carbon (DIG)
and pH determinations. Three laboratory
analysts share sample processing and
sample analysis duties. One analyst
performs aluminum extractions; the
second analyst performs sample filtration;
the third prepares and preserves aliquots,
prepares split samples for ERL-C, and
performs turbidity and true color deter-
minations.
In accordance with the QA plan for
WLS-I (Silverstein et al., 1987) adequate
records (in the form of logbooks, data
forms, and shipping forms) are main-
tained, and a uniform sample-coding
procedure is used. All field and field
laboratory forms are reviewed by the
laboratory coordinator. Appropriate copies
are sent to the QA staff at EMSL-LV for
review and to the data base manager at
Oak Ridge National Laboratory (ORNL) in
Oak Ridge, Tennessee, for data entry.
Calibration Study Operations
Most processing and analysis proce-
dures for the calibration study are identical
to those used for other WLS-I sample
batches, but the use of the two sampling
methods does require certain adaptations
in the field laboratory procedures. Each
calibration lake is sampled by one heli-
copter crew and by one ground crew. The
two crews collect samples from approxi-
mately the same location (the deepest
spot) on the lake. The ground crew
samples the lake first, and the helicopter
crew samples the lake as soon as possible
thereafter (optimally, within 1 hour). The
ground crew collects a routine sample
and a duplicate sample; the helicopter
crew collects a routine sample, a duplicate
sample, and a triplicate sample. Both
types of sampling crews use sample col-
lection techniques standard for all WLS-I
lakes. Use of the ground-access method,
however, presents logistical problems
that are unique to the WLS-I sampling
design. Ground crews that sample lakes
in wilderness areas might deliver samples
to the field laboratory as long as 1 to 5
days after collection: As a result, design-
ers of WLS-I are interested in the possible
effects of delayed sample preservation
(or "holding time").
To evaluate the effects of holding time,
the field laboratory preserves the ground
crew's samples on the collection date
and preserves two of the helicopter crew's
samples on the collection date. The third
sample collected by the helicopter crew
is refrigerated at the field laboratory for a
length of time equivalent to the time
difference between the receipt of the
samples collected by the ground crew
and by the helicopter crew.
The calibration study also has been
designed to provide data that can be used
to evaluate significant, systematic differ-
ences, in analytical results between
analytical laboratories. To meet this goal,
the field laboratory sends one sample
from each routine-duplicate pair (collected
by a ground crew) and one sample from
each routine-duplicate-triplicate set (col-
lected by a helicopter crew) to each of the
two analytical laboratories.
Analytical Laboratory Operations
WLS-I analytical laboratory procedures
are identical to those used during ELS-I.
Dally Operations
Analytical laboratory personnel receive
the samples shipped to them by the field
laboratory, inspect the samples for
damage, log in the sample batches,
analyze the samples, and prepare and
distribute data packages that document
the analyses performed.
When the samples arrive from the field
laboratory, analytical laboratory personnel
inspect the shipping boxes to ensure that
(1) all aliquot containers are present and
intact, (2) the sample IDs match the ones
listed on the shipping forms, and (3)
samples have been maintained at 4 °C or
colder during transport.
After samples are logged in, they are
analyzed. Each sample consists of seven
aliquots that are prepared at the field
laboratory (see Table 2); each aliquot is
processed differently, depending on the
analytes for which the aliquot is to be
analyzed. In addition, each analysis must
be conducted within a specified holding
time: 7,14, or 28 days, depending on the
analyte. (This holding time refers to the
number of days it takes to analyze the
sample in the analytical laboratory after
the sample has been processed and
preserved in the field laboratory, not the
time it takes to transport the sample from
the lake site to the field laboratory for
preservation and processing.) For each
batch of samples, analytical laboratory
preserved in the field laboratory, not the
time it takes to transport the sample from
the lake site to the field laboratory for
preservation and processing.) For each
batch of samples, analytical laboratory
personnel complete a data package.
Copies of the completed data package are
sent to the QA staff and to the data base
manager.
When the analyses have been com-!
pleted and the data packages have been
distributed, the aliquots are stored at the
analytical laboratory for at least 6 months.
The laboratory must receive written
notification from the QA manager before
the samples can be discarded.
On the basis of the analytical results
reported for internal and external QA and
QC samples, the QA staff, with the ap-
proval of the QA manager, can request
that the analytical laboratory confirm
reported values or that they reanalyze
selected samples or sample batches. In
such cases, sample reanalysis usually is
requested for a given variable on a per-
batch basis.
Extensive QC checks are incorporated
in the analytical procedures. These
procedures, acceptance criteria for the
results, and the corrective actions that
are required if the results are unaccept-
able are presented in the WLS-I QA Plan
(Silverstein et al., 1987) as well as in this
methods manual.
Analytical Methods
Determination of ANC, BNC,
andpH
While the pH is monitored and recorded
samples are titrated with standardize)
acid and base. Gran analysis technique i
used to analyze the titration data for th<
ANC and base neutralizing capacity (BNC
determinations. The pH is determine
before titrations are performed. The ait
equilibrated pH is determined similarly
after the sample is equilibrated with 30C
ppm CO2 in air for 20 minutes. Air equil
bration is expected to normalize pH value
by factoring out the day-to-day and sec
sonal fluctuations associated with dis
solved CO2 concentrations.
Determination of Ammonia
Alkaline phenol and hypochlorite rea
with ammonia to form an amount i
indophenol blue that is proportional
the ammonium concentration. The bli
color formed is intensified with sodiu
nitroprusside.
Determination of Chloride, Nitrat<
and Sulfate by Ion Chromatograpl
A filtered sample portion is inject
into an ion chromatograph. The sample
pumped through a precolumn, a separat
column, a suppressor column, and
conductivity detector. The precolumn a
the separator column are packed witr
low-capacity, anion-exchange resin. T
sample anions are separated into the
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two columns on the basis of their affinity
for the resin exchange sites. The sup-
pressor column reduces the conductance
of the eluant to a low level and converts
the sample anions to their acidic form. A
conductivity cell is used to measure the
separated anions in their acidic form.
Anions are identified on the basis of
retention time. Quantification is per-
formed by comparing sample peak heights
to a calibration curve that is generated
from known standards.
Determination of Dissolved
Organic Carbon and Dissolved
Inorganic Carbon
Dissolved organic carbon (DOC) is
determined in aliquot 4 (after the aliquot
is subjected to external sparging to re-
move DIG) by ultraviolet-promoted per-
sulfate oxidation followed by infrared
detection. DIG is determined directly by
acidifying aliquots to generate CO2; this
process is followed by infrared detection.
Determination of Total Dissolved
Fluoride by Ion-Selective Electrode
The total dissolved fluoride in a sample
is determined electrometrically. A fluoride
ion-selective electrode is used after a
total ionic strength buffer solution (TISAB)
is added to the aliquot. The TISAB adjusts
sample ionic strength, adjusts pH, and
breaks up fluoride complexes.
The potential of the fluoride ion-selec-
tive electrode varies logarithmically as a
function of the fluoride concentration. A
calibration curve is prepared by measuring
the potential of known fluoride standards
(after TISAB addition) and by plotting the
potential versus the fluoride concentration
(on a semi-log scale). Sample concentra-
tions are determined by comparing the
sample potential to the calibration curve.
Determination of Total Phosphorus
All forms of phosphorus, including
organic phosphorus, are converted to
orthophosphate by an acid-persulfate
digestion. Orthophosphate ions react with
ammonium molybdate in acidic solution
to form phosphomolybdic acid Upon re-
duction with ascorbic acid, this solution
produces an intensely colored blue com-
plex. Antimony potassium tartrate is
added to increase the rate of reduction.
Determination of Dissolved Silica
Silica reacts with molybdate reagent in
acidic media to form a yellow sili-
comolybdate complex. This complex is
reduced by ascorbic acid to form the
molybdate blue color. The silicomolybdate
complex may form as an alpha polymorph,
as a beta polymorph, or as a mixture of
the two. Because the absorbs nee maxima
of the two polymorphic forms are at dif-
ferent wavelengths, the pH of the mixture
is kept below 2.5. This condition favors
the formation of the beta polymorph. A
1-hour digestion with 1.0 M NaOH is
required to ensure that all the silica is
available for reaction with the molybdate
reagent.
Determination of Conductance
The conductance in samples is mea-
sured with a conductance meter and
conductivity cell. Potassium chloride
standards of known conductance are used
to calibrate the meter and cell. Samples
are analyzed at 25 °C.
Determination of Dissolved Metals
(Al, Ca, Fe, K, Mg, Mn, Na) by
Atomic Absorption Spectroscopy
Dissolved metals (Ca, Fe, K, Mg, Mn,
and Na) are determined in a filtered
sample (aliquot 1) by flame atomic ab-
sorption spectroscopy. Total Al is deter-
mined in an unfiltered sample (aliquot 7)
by graphite furnace atomic absorption
spectroscopy after acid digestion. Extract-
able Al is determined by graphite furnace
atomic absorption spectroscopy in a
sample that has been treated with 8-
hydroxyquinoline and that has been
extracted into methyl isobutyl ketone
(MIBK; aliquot 2).
Determination of Dissolved Metals
(Ca, Fe, Mg, and Mn) by Inductively
Coupled Plasma Atomic Emission
Spectroscopy
Samples are nebulized to produce an
aerosol. The aerosol is transported by an
argon carrier stream to an inductively
coupled argon plasma which is produced
by a radio-frequency (RF) generator. In
the plasma, which is at a temperature of
6,000 to 10,000 °K, the analytes in the
aerosol are atomized, ionized, and excited.
The excited ions and atoms emit light at
their characteristic wavelengths. The
spectra from all analytes are dispersed by
a grating spectrometer, and the intensities
of the lines are monitored by photo-
multiplier tubes. The photocurrents from
the photomultiplier tubes are processed
by a computer system. The signal is
proportional to the analyte concentration
and is calibrated by analyzing a series of
standards. A background correction tech-
nique must be used to compensate for
the variable contribution that the back-
ground intensity makes to the determina-
tion of trace elements. Background in-
tensity must be measured adjacent to
analyte lines during sampling analysis.
References
Bonoff, M. B., and A. W. Groeger, 1987.
National Surface Water Survey, Phase
I, Western Lake Survey Field Opera-
tions Report. U.S. Environmental Pro-
tection Agency, Las Vegas, Nevada.
Drouse, S. K., D. C. Hillman, L. W.
Creelman, and S. J. Simon, 1986.
National Surface Water Survey, East-
ern Lake Survey (Phase I Synoptic
Chemistry) Quality Assurance Plan.
EPA 600/4-86-008. U.S. Environ-
mental Protection Agency, Las Vegas,
Nevada.
Hillman, D. C., J. F. Potter, and S. J.
Simon, 1986. National Surface Water
Survey, Eastern Lake Survey (Phase I
Synoptic Chemistry) Analytical
Methods Manual. EPA 600/4-86-009.
U.S. Environmental Protection Agency,
Las Vegas, Nevada.
Silverstein, M. E., S. K. Drouse*, J. L.
Engels, M. L. Faber, and T. E. Mitchell-
Hall, 1987. National Surface Water
Survey, Western Lake Survey (Phase I
Synoptic Chemistry) Quality Assur-
ance Plan. U.S. Environmental Protec-
tion Agency, Las Vegas, Nevada.
-------
H B. Kerfoot and M. L. Falter are with Lockheed Engineering and Management
Services Company, Inc., Las Vegas, NV 89119.
Robert D. Schonbrod is the EPA Project Officer (see below).
The complete report, entitled "National Surface Water Survey, Western Lake
Survey (Phase ISynoptic Chemistry} Analytical Methods Manual." (Order
No. PB 87-234 928/AS; Cost: $18.95, 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:
Environmental Monitoring Systems Laboratory
U.S. Environmental Protection Agency
Las Vegas, NV 89193-3478
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use S300
EPA/600/S8-87/038
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