Method 440.0
Determination of Carbon and Nitrogen in Sediments and Particulates
of Estuarine/Coastal Waters Using Elemental Analysis
Carl F. Zimmermann
Carolyn W. Keefe
University of Maryland System
Center for Environmental Estuarine Studies
Chesapeake Biological Laboratory
Solomns, MD 20688-0038
and
Jerry Bashe
Technology Applications, Inc.
26 W. Martin Luther King Drive
Cincinnati, OH 45219
Revision 1.4
September 1997
Work Assignment Manager
Elizabeth J. Arar
National Exposure Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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Method 440.0
Determination of Carbon and Nitrogen in Sediments and Particulates
of Estuarine/Coastal Waters Using Elemental Analysis
1.0	Scope and Application
1.1	Elemental analysis is used to determine particu-
late carbon (PC) and particulate nitrogen (PN) in estua-
rine and coastal waters and sediment. The method
measures the total carbon and nitrogen irrespective of
source (inorganic or organic).
Chemical Abstracts Service
Analyte	Registry Numbers (CASRN)	
Carbon	7440-44-0
Nitrogen	1333-74-0	
1.2	The need to qualitatively or quantitatively deter-
mine the particulate organic fraction from the total
particulate carbon and nitrogen depends on the data-
quality objectives of the study. Section 11.4 outlines
procedures to ascertain the organic/inorganic particulate
ratio. The method performance presented in the method
was obtained on particulate samples with greater than
80% organic content. Performance on samples with a
greater proportion of particulate inorganic versus organic
carbon and nitrogen has not been investigated.
1.3	Method detection limits (MDLs)1 of 10.5 |jg/L and
62.3 |jg/L for PN and PC, respectively, were obtained for
a 200-mL sample volume. Sediment MDLs of PN and
PC are 84 mg/kg and 1300 mg/kg, respectively, for a
sediment sample weight of 10.00 mg. The method has
been determined to be linear to 4800 |jg of C and 700 |jg
of N in a sample. Multilaboratory study validation data are
in Section 13.
1.4	This method should be used by analysts experi-
enced in the theory and application of elemental analysis.
A minimum of 6 months experience with an elemental
analyzer is recommended.
1.5	Users of the method data should set the data-
quality objectives prior to analysis. Users of the method
must document and have on file the required initial
demonstration of performance data described in Section
9.2 prior to using the method for analysis.
2.0	Summary of Method
2.1	An accurately measured amount of particulate
matter from an estuarine water sample or an accurately
weighed dried sediment sample is combusted at 975°C
using an elemental analyzer. The combustion products
are passed over a copper reduction tube to convert the
oxides of N into molecular N. Carbon dioxide, water vapor
and N are homogeneously mixed at a known volume,
temperature and pressure. The mixture is released to a
series of thermal conductivity detectors/traps, measuring
in turn by difference, hydrogen (as water vapor), C (as
carbon dioxide) and N (as N2). Inorganic and organic C
may be determined by two methods which are also
presented.
3.0	Definitions
3.1	Sediment Sample - A fluvial, sand, or humic
sample matrix exposed to a marine, brackish or fresh
water environment. It is limited to that portion which may
be passed through a number 10 sieve or a 2-mm mesh
sieve.
3.2	Material Safety Data Sheet (MSDS) - Written
information provided by vendors concerning a chemical's
toxicity, health hazards, physical properties, fire, and
reactivity data including storage, spill, and handling pre-
cautions.
3.3	Instrument Detection Limit (IDL) - The mini-
mum quantity of analyte or the concentration equivalent
which gives an analyte signal equal to three times the
standard deviation of the background signal at the se-
lected wavelength, mass, retention time, absorbance line,
etc.
3.4	Method Detection Limit (MDL) - The minimum
concentration of an analyte that can be identified, mea-
sured, and reported with 99% confidence that the analyte
concentration is greater than zero.
3.5	Linear Dynamic Range (LDR) - The absolute
quantity over which the instrument response to an analyte
is linear.
3.6	Calibration Standard (CAL) - An accurately
weighed amount of a certified chemical used to calibrate
the instrument response with respect to analyte mass.
3.7	Conditioner- A standard chemical which is not
necessarily accurately weighed that is used to coat the
surfaces of the instrument with the analytes (water vapor,
carbon dioxide, and nitrogen).
3.8	External Standards (ES) - A pure analyte(s)
that is measured in an experiment separate from the
experiment used to measure the analyte(s) in the sample.
The signal observed for a known quantity of the pure
external standard(s) is used to calibrate the instrument
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response for the corresponding analyte(s). The instru-
ment response is used to calculate the concentrations of
the analyte(s) in the sample.
3.9	Response Factor (RF) — The ratio of the re-
sponse of the instrument to a known amount of analyte.
3.10	Laboratory Reagent Blank (LRB) — A blank
matrix (i.e., a precombusted filter or sediment capsule)
that is treated exactly as a sample including exposure to
all glassware, equipment, solvents, and reagents that are
used with other samples. The LRB is used to determine
if method analytes or other interferences are present in
the laboratory environment, the reagents, or the appa-
ratus.
3.11	Field Reagent Blank (FRB) — An aliquot of
reagent water or other blank matrix that is placed in a
sample container in the laboratory and treated as a
sample in all respects, including shipment to the sampling
site, exposure to sampling site conditions, storage,
preservation, and all analytical procedures. The purpose
of the FRB is to determine if method analytes or other
interferences are present in the field environment.
3.12	Laboratory Duplicates (LD1 and LD2) — Two
aliquots of the same sample taken in the laboratory and
analyzed separately with identical procedures. Analyses
of LD1 and LD2 indicate precision associated with labo-
ratory procedures, but not with sample collection, preser-
vation, or storage procedures.
3.13	Field Duplicates (FD1 and FD2) — Two sepa-
rate samples collected at the same time and place under
identical circumstances and treated exactly the same
throughout field and laboratory procedures. Analyses of
FD1 and FD2 give a measure of the precision associated
with sample collection, preservation and storage, as well
as with laboratory procedures.
3.14	Laboratory Fortified Blank (LFB) — An aliquot
of reagent water or other blank matrices to which known
quantities of the method analytes are added in the
laboratory. The LFB is analyzed exactly like a sample,
and its purpose is to determine whether the method is in
control, and whether the laboratory is capable of making
accurate and precise measurements.
3.15	Laboratory Fortified Sample Matrix (LFM) — An
aliquot of an environmental sample to which known
quantities of the method analytes are added in the
laboratory. The LFM is analyzed exactly like a sample,
and its purpose is to determine whether the sample matrix
contributes bias to the analytical results. The background
concentrations of the analytes in the sample matrix must
be determined in a separate aliquot and the measured
values in the LFM corrected for background concentra-
tions.
3.16	Standard Reference Material (SRM) — Material
which has been certified for specific analytes by a variety
of analytical techniques and/or by numerous laboratories
using similar analytical techniques. These may consist of
pure chemicals, buffers or compositional standards.
These materials are used as an indication of the accuracy
of a specific analytical technique.
3.17 Quality Control Sample (QCS) - A solution of
method analytes of known concentrations which is used
to fortify an aliquot of LRB or sample matrix. The QCS is
obtained from a source external to the laboratory and
different from the source of calibration standards. It is
used to check laboratory performance with externally
prepared test materials.
4.0	Interferences
4.1	There are no known interferences for estua-
rine/coastal water or sediment samples. The presence of
C and N compounds on laboratory surfaces, on fingers,
in detergents and in dust necessitates the utilization of
careful techniques (i.e., the use of forceps and gloves) to
avoid contamination in every portion of this procedure.
5.0	Safety
5.1	The toxicity or carcinogenicity of each reagent
used in this method has not been fully established. Each
chemical should be regarded as a potential health hazard
and exposure to these compounds should be as low as
reasonably achievable. Each laboratory is responsible for
maintaining a current awareness file of OSHA regulations
regarding the safe handling of the chemicals specified in
this method.2"5 A reference file of material safety data
sheets (MSDS) should also be made available to all
personnel involved in the chemical analysis.
5.2	The acidification of samples containing reactive
materials may result in the release of toxic gases, such as
cyanides or sulfides. Acidification of samples should be
done in a fume hood.
5.3	All personnel handling environmental samples
known to contain or to have been in contact with human
waste should be immunized against known disease
causative agents.
5.4	Although most instruments are adequately
shielded, it should be remembered that the oven tem-
peratures are extremely high and that care should be
taken when working near the instrument to prevent
possible burns.
5.5	It is the responsibility of the user of this method to
comply with relevant disposal and waste regulations. For
guidance see Sections 14.0 and 15.0.
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6.0	Apparatus and Equipment
6.1	Elemental Analyzer
6.1.1 An elemental analyzer capable of maintaining a
combustion temperature of 975°C and analyzing particu-
late samples and sediment samples for elemental C and
N. The Leeman Labs Model 240 XA Elemental Analyzer
was used to produce the data presented in this method.
6.2	A gravity convection drying oven. Capable of
maintaining 103-105°C for extended periods of time.
6.3	Muffle furnace. Capable of maintaining 875°C ±
15°C.
6.4	Ultra-micro balance. Capable of accurately
weighing to 0.1 |jg. Desiccant should be kept in the
weighing chamber to prevent hygroscopic effects.
6.5	Vacuum pump or source capable of maintaining
up to 10 in. Hg of vacuum.
6.6	Mortar and pestle.
6.7	Desiccator, glass.
6.8	Freezer, capable of maintaining -20°C ± 5°C.
6.9	47-mm or 25-mm vacuum filter apparatus made
up of a glass filter tower, fritted glass disk base and 2-L
vacuum flask.
6.10	13-mm Swinlok filter holder.
6.11	Teflon-tipped, flat blade forceps.
6.12	Labware — All reusable labware (glass, quartz,
polyethylene, PTFE, FEP, etc.) should be sufficiently
clean for the task objectives. Several procedures found
to provide clean labware include washing with a detergent
solution, rinsing with tap water, soaking for 4 hr or more
in 20% (v/v) HCI, rinsing with reagent water and storing
clean. All traces of organic material must be removed to
prevent C-N contamination.
6.12.1	Glassware — Volumetric flasks, graduated
cylinders, vials and beakers.
6.12.2	Vacuum filter flasks - 250 mL and 2 L, glass.
6.12.3	Funnel, 6.4 mm i.d., polyethylene.
6.12.4	Syringes, 60-mL, glass.
7.0	Reagents and Standards
7.1	Reagents may contain elemental impurities which
affect analytical data. High-purity reagents that conform
to the American Chemical Society specifications6 should
be used whenever possible. If the purity of a reagent is in
question, analyze for contamination. The acid used for
this method must be of reagent grade purity or equivalent.
A suitable acid is available from a number of manu-
facturers.
7.2	Hydrochloric acid, concentrated (sp. gr. 1.19)-
HCI.
7.3	Acetanilide, 99.9% + purity, C8H19NO (CASRN
103-84-4).
7.4	Blanks - Three blanks are used for the analysis.
Two blanks are instrument related. The instrument zero
response (ZN) is the background response of the instru-
ment without sample holding devices such as capsules
and sleeves. The instrument blank response (BN) is the
response of the instrument when the sample capsule,
sleeve and ladle are inserted for analysis without standard
or sample. The BN is also the laboratory reagent blank
(LRB) for sediment samples. The LRB for water samples
includes the capsule, sleeve, ladle and a precombusted
filter without standard or sample. These blanks are
subtracted from the uncorrected instrument response
used to calculate concentration in Sections 12.3 and 12.4.
7.4.1 Laboratory fortified blank (LFB) — The third blank
is the laboratory fortified blank. For sediment analysis,
add a weighed amount of acetanilide in an aluminum
capsule and analyze for PC and PN (Section 9.3.2). For
aqueous samples, place a weighed amount of acetanilide
on a glass fiber filter the same size as used for the
sample filtration. Analyze the fortified filter for PC and PN
(Section 9.3.2)
7.5	Quality Control Sample (QCS) - For this meth-
od, the QCS can be any assayed and certified sediment
or particulate sample which is obtained from an external
source. The Canadian Reference Material, BCSS-1, is
just such a material and was used in this capacity for the
data presented in this method. The percent PC has been
certified in this material but percent PN has not.
8.0	Sample Collection, Preservation and
Storage
8.1	Water Sample Collection - Samples collected
for PC and PN analyses from estuarine/coastal waters
are normally collected from a ship using one of two
methods; hydrocast or submersible pump systems. Fol-
low the recommended sampling protocols associated
with the method used. Whenever possible, immediately
filter the samples as described in Section 11.1.1. Store
the filtered sample pads by freezing at -20°C or storing in
a desiccator after drying at 103-105° C for 24 hr. No
significant difference has been noted in comparing the
two storage procedures for a time period of up to 100
days. If storage of the water sample is necessary, place
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the sample into a clean amber bottle and store at 4°C
until filtration is done.
8.1.1 The volume of water sample collected will vary
with the type of sample being analyzed. Table 1 provides
a guide for a number of matrices of interest. If the matrix
cannot be classified by this guide, collect 2 x 1L of water
from each site. A minimum filtration volume of 200 mL is
recommended.
8.2 Sediment Sample Collection - Estua-
rine/coastal sediment samples are collected with benthic
samplers. The type of sampler used will depend on the
type of sample needed by the data-quality objectives.7
Store the wet sediment in a clean jar and freeze at -20°C
until ready for analysis.
8.2.1 The amount of sediment collected will depend on
the sample matrix and the elemental analyzer used. A
minimum of 10 g is recommended.
9.0	Quality Control
9.1	Each laboratory using this method is required to
operate a formal quality control (QC) program. The
minimum requirements of this program consist of an initial
demonstration of laboratory capability and the continued
analysis of laboratory reagent blanks, laboratory dupli-
cates, field duplicates and calibration standards analyzed
as samples as a continuing check on performance. The
laboratory is required to maintain performance records
that define the quality of data thus generated.
9.2	Initial Demonstration of Performance
(Mandatory)
9.2.1	The initial demonstration of performance is used
to characterize instrument performance (MDLs, linear dy-
namic range) and laboratory performance (analysis of QC
samples) prior to the analyses conducted by this method.
9.2.2	Linear dynamic range (LDR) — The upper limit of
the LDR must be established by determining the signal
responses from a minimum of three different concentra-
tion standards across the range, one of which is close to
the upper limit of the LDR. Determined LDRs must be
documented and kept on file. The LDR which may be
used for the analysis of samples should be judged by the
analyst from the resulting data. The upper LDR limit
should be an observed signal no more than 10% below
the level extrapolated from the lower standards. Deter-
mined sample analyte concentrations that are 90% and
above the upper LDR must be reduced in mass and
reanalyzed. New LDRs should be determined whenever
there is a significant change in instrument response and
for those analytes that periodically approach the upper
LDR limit, every 6 months or whenever there is a change
in instrument analytical hardware or operating conditions.
9.2.3	Quality control sample (QCS) (Section 7.5) —
When beginning the use of this method, on a quarterly
basis or as required to meet data quality needs, verify the
calibration standards and acceptable instrument perfor-
mance with the analyses of a QCS. If the determined
concentrations are not within ± 5% of the stated values,
performance of the determinative step of the method is
unacceptable. The source of the problem must be iden-
tified and corrected before either proceeding with the
initial determination of MDLs or continuing with analyses.
9.2.4	Method detection limits (MDLs) - MDLs should
be established for PC and PN using a low level estuarine
water sample, typically three to five times higher than the
estimated MDL. The same procedure should be followed
for sediments. To determine MDL values, analyze seven
replicate aliquots of water or sediment and process
through the entire analytical procedure (Section 11).
These replicates should be randomly distributed through-
out a group of typical analyses. Perform all calculations
defined in the method (Section 12) and report the con-
centration values in the appropriate units. Calculate the
MDL as follows:1
MDL = (t) X (S)
where, S = Standard deviation of the repli-
cate analyses.
t = Student's t value for n-1
degrees of freedom at the
99% confidence limit; t = 3.143
for six degrees of freedom.
MDLs should be determined whenever a significant
change in instrumental response, change of operator, or
a new matrix is encountered.
9.3 Assessing Laboratory Performance
(Mandatory)
9.3.1 Laboratory reagent blank (LRB) — The laboratory
must analyze at least one LRB (Section 3.10) with each
batch of 20 or fewer samples of the same matrix. LRB
data are used to assess contamination from the labora-
tory environment. LRB values that exceed the MDL
indicate laboratory or reagent contamination. When LRB
values constitute 10% or more of the analyte level deter-
mined for a sample, fresh samples or field duplicates of
the samples must be prepared and analyzed again after
the source of contamination has been corrected and
acceptable LRB values have been obtained. For aque-
ous samples the LRB is a precombusted filter of the
same type and size used for samples.
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9.3.2 Laboratory fortified blank (LFB) — The laboratory
must analyze at least one LFB (Section 7.4.1) with each
batch of samples. Calculate accuracy as percent recov-
ery. If the recovery of any analyte falls outside the
required control limits of 85-115%, that analyte is judged
out of control, and the source of the problem should be
identified and resolved before continuing analyses.
Response factor (|jv/|jg) = RN-ZN-BN
WTN
where, RN = Average instrument response to
standard (|jv)
ZN = Instrument zero response (|jv)
BN = Instrument blank response (|jv)
9.3.3 The laboratory must use LFB analyses data to
assess laboratory performance against the required con-
trol limits of 85-115% (Section 9.3.2). When sufficient
internal performance data become available (usually a
minimum of 20-30 analyses), optional control limits can
be developed from the percent mean recovery (x) and the
standard deviation (S) of the mean recovery. These data
can be used to establish the upper and lower control
limits as follows:
Upper Control Limit = x + 3S
Lower Control Limit = x - 3S
The optional control limits must be equal to or better than
the required control limits of 85-115%. After each five to
ten new recovery measurements, new control limits can
be calculated using only the most recent 20-30 data
points. Also the standard deviation (S) data should be
used to establish an ongoing precision statement for the
level of concentrations included in the LFB. These data
must be kept on file and be available for review.
9.4 Assessing Analyte Recovery and Data
Quality
9.4.1 Percent recoveries cannot be readily obtained
from particulate samples. Consequently, accuracy can
only be assessed by analyzing check standards as
samples and quality control samples (QCS). The use of
laboratory fortified matrix samples has not been as-
sessed.
10.0	Calibration and Standardization
10.1	Calibration — After following manufacturer's
installation and temperature stabilization procedures,
daily calibration procedures must be performed and
evaluated before sample analysis may begin. Single
point or standard curve calibrations are possible, de-
pending on instrumentation.
10.1.1 Establish single response factors (RF) for each
element (C,H, and N) by analyzing three weighed portions
of calibration standard (acetanilide). The mass of
calibration standard should provide a response within
20% of the response expected for the samples being
analyzed. Calculate the (RF) for each element using the
following formula:
and, WTN = (M)(Na)(AW/MW)
where, M = The mass of standard material in
M9
Na = Number of atoms of C, N or H, in
a molecule of standard material
AW = Atomic weight of C (12.01), N
(14.01) or H (1.01)
MW = Molecular weight of standard
material (135.2 for acetanilide)
If instrument response is in units other than |jv, then
change the formula accordingly.
10.1.2 For standard curve preparation, the range of
calibration standard masses used should be such that the
low concentration approaches but is above the MDL and
the high concentration is above the level of the highest
sample, but no more than 90% of the linear dynamic
range. A minimum of three concentrations should be
used in constructing the curve. Measure response versus
mass of element in the standard and perform a
regression on the data to obtain the calibration curve.
11.0	Procedure
11.1	Aqueous Sample Preparation
11.1.1 Water Sample Filtration - Precombust GF/F
glass fiber filters at 500°C for 1.5 hr. The diameter of filter
used will depend on the sample composition and instru-
ment capabilities (Section 8.1.1). Store filters covered if
not immediately used. Place a precombusted filter on
fritted filter base of the filtration apparatus and attach the
filtration tower. Thoroughly shake the sample container
to suspend the particulate matter. Measure and record
the required sample volume using a graduated cylinder.
Pour the measured sample into the filtration tower, no
more than 50 mL at a time. Filter the sample using a
vacuum no greater than 10 in. of Hg. Vacuum levels
greater than 10 in. of Hg can cause filter rupture. If less
than the measured volume of sample can be practically
filtered due to clogging, measure and record the actual
volume filtered. Do not rinse the filter following filtration.
It has been demonstrated that sample loss occurs when
the filter is rinsed with an isotonic solution or the filtrate.8
Air dry the filter after the sample has passed through by
continuing the vacuum for 30 sec. Using Teflon-coated
flat-tipped forceps, fold the filters in half while still on the
fritted glass base of the filter apparatus. Store filters as
described in Section 8.
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11.1.2	If the sample has been stored frozen, place the
sample in a drying oven at 103-105° C for 24 hr before
analysis and dry to a constant weight. Precombust one
nickel sleeve at 875° C for 1 hr for each sample.
11.1.3	Remove the filter pads containing the particulate
material from the drying oven and insert into a pre-
combusted nickel sleeve using Teflon-coated flat-tipped
forceps. Tap the filter pad using a stainless steel rod.
The sample is ready for analysis.
11.2	Sediment Samples Preparation
11.2.1	Thaw the frozen sediment sample in a 102-
105°C drying oven for at least 24 hr before analysis and
dry to a constant weight. After drying, homogenize the
dry sediment with a mortar and pestle. Store in a desic-
cator until analysis. Precombust aluminum capsules at
550°C in a muffle furnace for 1.5 hr for each sediment
sample being analyzed. Precombust one nickel sleeve
at 875°C for 1 hr for each sediment sample.
11.2.2	Weigh 10 mg of the homogenized sediment to
the nearest 0.001 mg with an ultra-micro balance into a
precombusted aluminum capsule. Crimp the top of the
aluminum capsule with the Teflon-coated flat-tipped for-
ceps and place into a precombusted nickel sleeve. The
sample is ready for analysis.
11.3	Sample Analysis
11.3.1	Measure instrument zero response (Section 7.4)
and instrument blank response (Section 7.4) and record
values. Condition the instrument by analyzing a condi-
tioner. Calibrate the instrument according to Section 10
and analyze all preliminary QC samples as required by
Section 9. When satisfactory control has been estab-
lished, analyze samples according to the instrument
manufacturer's recommendations. Record all response
data.
11.3.2	Report data as directed in Section 12.
11.4	Determination of Particulate Organic and
Inorganic Carbon
11.4.1	Method 1: Thermal Partitioning - The difference
found between replicate samples, one of which has been
analyzed for total PC and PN and the other which was
muffled at 550°C and analyzed is the particulate organic
component of that sample. This method of thermally
partitioning organic and inorganic PC may underestimate
slightly the carbonate minerals' contribution in the
inorganic fraction since some carbonate minerals
decompose below 500°C, although CaC03 does not.9
11.4.2	Method 2: Fuming HCi - Allow samples to dry
overnight at 103-105°C and then place in a desiccator
containing concentrated HCI, cover and fume for 24 hr in
a hood. The fuming HCI converts inorganic carbonate in
the samples to water vapor, C02 and calcium chloride.
Analyze the samples for particulate C. The resultant data
are particulate organic carbon.10
12.0	Data Analysis and Calculations
12.1	Sample data should be reported in units of |jg/L
for aqueous samples and mg/kg dry weight for sediment
samples.
12.2	Report analyte concentrations up to three signifi-
cant figures for both aqueous and sediment samples.
12.3	For aqueous samples, calculate the sample con-
centration using the following formula:
Corrected
Concentration (|jg/L) = sample response (ijv)	
Sample volume (L) x RF (|jv/|jg)
where, RF = Response Factor (Section 10.1.1)
Corrected Sample Response (Section
7.4)
12.4	For sediment samples, calculate the sample con-
centration using the following formula:
Corrected
Concentration (mg/kg) = sample response (ijv)	
Sample weight (g) x RF (|jv/|jg)
where,	RF = Response Factor (Section 10.1.1)
Corrected Sample Response (Section
7.4)
Note:	Units of |jg/g = mg/kg
12.5	The QC data obtained during the analyses
provide an indication of the quality of the sample data and
should be provided with the sample results.
13.0	Method Performance
13.1	Single Laboratory Performance
13.1.1	Single laboratory performance data for aqueous
samples from the Chesapeake Bay are provided in Table
2.
13.1.2	Single-laboratory precision and accuracy data for
the marine sediment reference material, BCSS-1, are
listed in Table 3.
13.2	Multilaboratory Performance
13.2.1 In a multilab study, 13 participants analyzed
sediment and filtered estuarine water samples for
particulate carbon and nitrogen. The data were analyzed
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using the statistical procedures recommended in ASTM
D2777-86 for replicate designs. See Table 4 for
summary statistics.
13.2.2	Accuracy as mean recovery was estimated from
the analyses of the NRC of Canada Marine Sediment
Reference Material, BCSS-1. Mean recovery was 98.2%
of the certified reference carbon value and 100% of the
noncertified nitrogen value.
13.2.3	Overall precision for analyses of carbon and
nitrogen in sediments was 1-11% RSD, while the
analyses of both particulate carbon and nitrogen in
estuarine water samples was 9-14% RSD.
13.2.4	Single analyst precision for carbon and nitrogen
in sediment samples was 1-8% RSD and 4-9% for water
samples.
13.2.5	Pooled method detection limits (p-MDLs) were
calculated using the pooled single analyst standard
deviations. The p-MDLs for particulate nitrogen and
carbon in estuarine waters were 0.014 mg N/L and 0.064
mg C/L , respectively. The p-MDLs for percent carbon
and nitrogen in estuarine sediments were not estimated
because the lowest concentration sediment used in the
study was still 20 times higher than the estimated MDLs.
Estimates of p-MDLs from these data would be
unrealistically high.
14.0	Pollution Prevention
14.1	Pollution prevention encompasses any technique
that reduces or eliminates the quantity or toxicity of waste
at the point of generation. Numerous opportunities for
pollution prevention exist in laboratory operation. The
EPA has established a preferred hierarchy of environ-
mental management techniques that places pollution
prevention as the management option of first choice.
Whenever feasible, laboratory personnel should use
pollution prevention techniques to address their waste
generation. When wastes cannot be feasibly reduced at
the source, the Agency recommends recycling as the next
best option.
14.2	For information about pollution prevention that
may be applicable to laboratories and research institu-
tions, consult Less is Better: Laboratory Chemical Man-
agement for Waste Reduction, available from the Ameri-
can Chemical Society's Department of Government Re-
lations and Science Policy, 1155 16th Street N.W.,
Washington D.C. 20036, (202) 872-4477.
15.0	Waste Management
15.1	The Environmental Protection Agency requires
that laboratory waste management practices be con-
ducted consistent with all applicable rules and regula-
tions. The Agency urges laboratories to protect the air,
water and land by minimizing and controlling all releases
from hoods and bench operations, complying with the
letter and spirit of any sewer discharge permits and
regulations, and by complying with all solid and hazard-
ous waste regulations, particularly the hazardous waste
identification rules and land disposal restrictions. For
further information on waste management consult The
Waste Management Manual for Laboratory Personnel,
available from the American Chemical Society at the
address listed in Section 14.2.
16.0 References
1.	40 CFR, Part 136, Appendix B. Definition and
Procedure for the Determination of the Method
Detection Limit. Revision 1.11.
2.	Carcinogens - Working With Carcinogens,
Department of Health, Education, and Welfare,
Public Health Service, Center for Disease Control,
National Institute for Occupational Safety and
Health, Publication No. 77-206, Aug. 1977.
3.	OSHA Safety and Health Standards, General
Industry, (29 CFR 1910), Occupational Safety and
Health Administration, OSHA 2206, (Revised,
January 1976).
4.	Safety in Academic Chemistry Laboratories,
American Chemical Society Publication, Committee
on Chemical Safety, 3rd Edition, 1979.
5.	Proposed OSHA Safety and Health Standards,
Laboratories, Occupational Safety and Health
Administration, Federal Register, July 24, 1986.
6.	Rohrdough, W.G. et al. Reagent Chemicals,
American Chemical Society Specifications, 7th
Edition. American Chemical Society, Washington,
DC, 1986.
7.	Holme, N.A. and A.D. Mclntyre (eds). 1971.
Methods for the Study of Marine Benthos.
International Biome Program. IBP Handbook #16.
F.A. Davis Co., Philadelphia, PA.
8.	Hurd, D.C. and D.W. Spencer (eds). 1991. Marine
Particles: Analysis and Characterization.
Geophysical Monograph: 63, American Geophysical
Union, Washington, DC 472p.
9.	Hirota, J. and J.P. Szyper. 1975. Separation of total
particulate carbon into inorganic and organic
components. Limnol. and Oceanogr. 20:896-900.
10.	Grasshoff, K., M. Ehrhardt and K. Kremling (eds).
1983. Methods of Seawater Analysis. Verlag
Chemie.
Revision 1.4 September 1997
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17.0 Tables, Diagrams, Flowcharts, and
Validation Data
Table 1. Filter Diameter Selection Guide
Sample matrix
47mm
Filter diameter
25mm
13mm
Sample matrix volume
Open ocean
Coastal
Estuarine
(low particulate)
Estuarine
(high particulate)
2000 mL	500 mL
1000 mL 400-500 mL
500-700 mL 250-400 mL
100-400 mL
75-200 mL
100 mL
100 mL
50 mL
25 mL
Table 2. Performance Data-Chesapeake Bay Aqueous
Samples
Measured Measured
nitrogen carbon
concentration S.D.A concentration S.D.A
Sample (ug/L)	(ug/L)	(ug/L)	(ug/L)
1	147	±4	1210	±49
2	148	± 11	1240	±179
3	379	± 51	3950	± 269
	4	122	±9	1010	± 63
A Standard deviation based on 7 replicates.
Table 3. Precision and Accuracy Data - Canadian
Sediment Reference Material BCSS-1
Mean
measured
Element T.V.A	value (%) %RSDB %Recoveryc
Carbon 2.19%	2.18	± 3.3	99.5
Nitrogen 0.195%	0.194	±3i9	99.5
A True value. Carbon value is certified; nitrogen value is listed but
not certified
B Percent relative standard deviation based on 10 replicates.
c As calculated from T.V.
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Table 4. Overall and Single Analyst Precision Estimates from Collaborative Study
Analyte
Sample
N(1)
Mean(2)
Cone.
Overall
Std. Dev.
Overall
%RSD
Analyst
Std. Dev.
Analyst
%RSD
Particulate
Nitrogen
(as N) in
Estuarine
Waters
A
11
0.0655
0.0081
12.4%
0.0050
7.6%
B
12
0.0730
0.0076
10.3%
0.0057
7.7%
C
12
0.0849
0.0110
12.9%
0.0060
7.1%
D
12
0.126
0.0138
11.0%
0.0071
5.6%
E
11
0.182
0.0245
13.5%
0.0157
8.6%

Nitrogen
(as %N) in
Estuarine
Water
1
10
0.178
0.0190
10.7%
0.0131
7.3%
2
10
0.295
0.0114
3.9%
0.0046
1.6%
3
10
0.436
0.0178
4.1%
0.0104
2.4%
4
10
0.497
0.0183
3.7%
0.0082
1.6%
5
10
0.580
0.0207
3.6%
0.0150
2.6%

Particulate
Carbon
(as C) in
Estuarine
Waters
B
12
0.369
0.0505
13.7%
0.0222
6.0%
A
12
0.417
0.0490
11.8%
0.0230
5.5%
D
12
0.619
0..0707
11.4%
0.0226
3.6%
C
12
0.710
0.0633
8.9%
0.0367
5.2%
E
12
0.896
0.1192
13.3%
0.0569
6.4%

Carbon
(as %C) in
Estuarine
Sediments
1
13
1.78
0.1517
8.5%
0.1346
7.6%
2
13
2.55
0.0372
1.5%
0.0204
0.8%
3
13
3.18
0.0435
1.4%
0.0348
1.1%
4
13
4.92
0.1201
2.4%
0.0779
1.6%
5
13
5.92
0.0621
1.1%
0.0547
0.9%
(1)	N = Number of participants whose data was used.
(2)	Concentration in mg/L or percent, as indicated.
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