EPA-821-R-01-015
January 2001
METHOD 1684
Total, Fixed, and Volatile Solids
in Water, Solids, and Biosolids
Draft
January 2001
U.S. Environmental Protection Agency
Office of Water
Office of Science and Technology
Engineering and Analysis Division (4303)
1200 Pennsylvania Ave. NW
Washington, DC 20460
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Method 1684
Acknowledgments
This method was prepared under the direction of William A. Telliard of the U.S. Environmental Protection
Agency's (EPA's) Office of Water (OW), Engineering and Analysis Division (EAD). The method was
prepared under EPA Contract 68-C-98-139 by DynCorp with assistance from Quality Works, Inc.
Disclaimer
This draft method has been reviewed and approved for publication by the Analytical Methods Staff within
the Engineering and Analysis Division of the U.S. Environmental Protection Agency. Mention of trade
names or commercial products does not constitute endorsement or recommendation for use. EPA plans
further validation of this draft method. The method may be revised following validation to reflect results of
the study. This method version contains minor editorial changes to the February 1999 version.
EPA welcomes suggestions for improvement of this method. Suggestions and questions concerning this
method or its application should be addressed to:
William A. Telliard
USEPA Office of Water
Analytical Methods Staff
Mail Code 4303
1200 Pennsylvania Ave., NW
Washington, DC 20460
Phone: 202/260-7134
Fax: 202/260-7185
Requests for additional copies of this publication should be directed to:
Water Resource Center
Mail Code RC-4100
1200 Pennsylvania Ave., NW
Washington, DC 20460
(202) 260-7786 or (202) 260-2814
Draft-January 2001
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Method 1684
Note: This method is performance based. The laboratory is permitted to modify or omit any steps or
procedure, provided that all performance requirements in this method are met. The laboratory may not
omit any quality control analyses. The terms "shall", "must", and "may not" indicate steps and
procedures required for producing reliable results. The terms "should" and "may" indicate optional
steps that may be modified or omitted if the laboratory can demonstrate that the modified method
produces results equivalent or superior to results produced by this method.
Draft-January 2001
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Method 1684
Method 1684
Total, Fixed, and Volatile Solids in Water, Solids, and Biosolids
1.0 Scope and Application
1.1 This method is applicable to the determination of total solids and the fixed and volatile fractions in
such solid and semisolid samples as soils, sediments, biosolids (municipal sewage sludge), sludge
separated from water and wastewater treatment processes, and sludge cakes from vacuum
filtration, centrifugation, or other sludge dewatering processes.
1.2 This method is for use in the United States Environmental Protection Agency's (EPA's) data
gathering and monitoring programs under the Clean Water Act, the Resource Conservation and
Recovery Act, the Comprehensive Environmental Response, Compensation, and Liability Act, and
the Safe Drinking Water Act.
1.3 Method detection limits (MDLs) and minimum levels (MLs) have not been formally established for
this draft method. These values will be determined during the validation studies.
1.4 This method is performance based. The laboratory is permitted to omit any step or modify any
procedure (e.g. to overcome interferences, to lower the cost of measurement), provided that all
performance requirements in this method are met. Requirements for establishing method
equivalency are given in Section 9.1.2.
1.5 Each laboratory that uses this method must demonstrate the ability to generate acceptable results
using the procedure in Section 9.2.
2.0 Summary of Method
2.1 Sample aliquots of 25-50 g are dried at 103 °C to 105 °C to drive off water in the sample.
2.2 The residue from Section 2.1 is cooled, weighed, and dried again at 550°C to drive off volatile
solids in the sample.
2.3 The total, fixed, and volatile solids are determined by comparing the mass of the sample before and
after each drying step.
3.0 Definitions
Definitions for terms used in this method are given in the glossary at the end of the method (Section
18).
4.0 Interferences
4.1 Sampling, subsampling, and pipetting multi-phase samples may introduce serious errors. Make
and keep such samples homogeneous during transfer. Use special handling to ensure sample
integrity when subsampling. Mix small samples with a magnetic stirrer. If visible suspended
Draft-January 2001 1
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Method 1684
solids are present, pipette with wide-bore pipettes. If part of a sample adheres to the sample
container, intensive homogenization is required to ensure accurate results. When dried, some
samples form a crust that prevents evaporation; special handling such as extended drying times are
required to deal with this. Avoid using a magnetic stirrer with samples containing magnetic
particles.
4.2 The temperature and time of residue drying has an important bearing on results. Problems such as
weight losses due to volatilization of organic matter, and evolution of gases from heat-induced
chemical decomposition, weight gains due to oxidation, and confounding factors like mechanical
occlusion of water and water of crystallization depend on temperature and time of heating. It is
therefore essential that samples be dried at a uniform temperature, and for no longer than specified
in the method. Each sample requires close attention to desiccation after drying. Minimize the time
the desiccator is open because moist air may enter and be absorbed by the samples. Some samples
may be stronger desiccants than those used in the desiccator and may take on water. If uptake of
water by a sample is suspected, the operator should weigh the sample to see if it gains weight while
in the desiccator. If the sludge is indeed taking on water, then a vacuum desiccator should be used.
4.3 Residues dried at 103 °C to 105 °C may retain some bound water as water of crystallization or as
water occluded in the interstices of crystals. The residues also lose CO2 in the conversion of
bicarbonate to carbonate. The residues usually lose only slight amounts of organic matter by
volatilization at this temperature. Because removal of occluded water is marginal at this
temperature, attainment of constant weight may be very slow.
4.4 Results for residues high in oil or grease may be questionable because of the difficulty of drying to
constant weight in a reasonable time.
4.5 The determination of both total and volatile solids is subject to negative error due to loss of
ammonium carbonate and volatile organic matter during the drying step at 103 °C to 105 °C.
Carefully observe specified drying time and temperature to control losses of volatile inorganic salts
if these are a problem.
5.0 Safety
5.1 This method does not address all safety issues associated with its use. The toxicity or
carcinogenicity of reagents used in this method have not been fully established. Each chemical and
environmental sample should be regarded as a potential health hazard and exposure should be
minimized. The laboratory is responsible for maintaining a safe work environment and a current
awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this
method. A reference file of material safety data sheets (MSDSs) should be available to all
personnel involved in these analyses. Additional information on laboratory safety can be found in
References 5-7.
5.2 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.
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Method 1684
6.0 Equipment and Supplies
NOTE: Brand names, suppliers, and part numbers are cited for illustrative purposes only. No
endorsement is implied. Equivalent performance may be achieved using equipment and
materials other than those specified here, but demonstration of equivalent performance that
meets the requirements of this method is the responsibility of the laboratory.
6.1 Evaporating dishes-Dishes of 100-mL capacity. The dishes may be made of porcelain (90-mm
diameter), platinum, or high-silica glass.
6.2 Watch glass-Capable of covering the evaporating dishes (Section 6.1).
6.3 Muffle furnace-Capable of maintaining a uniform temperature of 5 5 0 ° C throughout the drying
chamber.
6.4 Steam bath for evaporation of liquid samples.
6.5 Desiccator-Moisture concentration in the desiccator should be monitored by an instrumental
indicator or with a color-indicator desiccant.
6.6 Drying oven-Thermostatically-controlled, capable of maintaining a uniform temperature of 103 °C
to 105 °C throughout the drying chamber.
6.7 Analytical balance-Capable of weighing to 0.1 mg for samples having a mass up to 200 g.
6.8 Reference weights-2 mg, 1000 mg, and 50g class "S" weights.
6.9 Container handling apparatus-Gloves, tongs, or a suitable holder for moving and handling hot
containers after drying.
6.10 Sample handling apparatus-Spatulas, spoonulas, funnels, or other equipment for transfer and
manipulation of sample.
6.11 Bottles-Glass or plastic bottles of a suitable size for sample collection.
6.12 Rubber gloves (Optional)
6.13 No. 7 Cork borer (Optional)
6.14 Dessicant (Optional)
7.0 Reagents and Standards
7.1 Reagent water-Deionized, distilled, or otherwise purified water.
7.2 Quality control spiking solution- If a commercially available standard can be purchased that
contains standard fixed and volatile solids, the laboratory may use that standard. The laboratory
may also prepare a spiking solution. One possible recipe is given below for a NaCl-KHP solution.
Draft-January 2001 3
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Method 1684
7.2.1 Dissolve 0.10 g sodium chloride (NaCl) in 500 mL reagent water. Mix to dissolve.
7.2.2 Add 0.10 g potassium hydrogen phthalate (KHP) to the NaCl solution (Section 7.2.1) and
mix. If the KHP does not dissolve readily, warm the solution while mixing. Dilute to 1 L
with reagent water. Store at 4°C. Assuming 100% volatility of the acid phthalate ion, this
solution contains 200 mg/L total solids, 81.0 mg/L volatile solids, and 119 mg/L fixed
solids.
8.0 Sample Collection, Preservation, and Storage
8.1 Use resistant-glass or plastic bottles to collect sample for solids analysis, provided that the material
in suspension does not adhere to container walls. Sampling should be done in accordance with
Reference 16.10. Begin analysis as soon as possible after collection because of the impracticality
of preserving the sample. Refrigerate sample at 4 °C up to the time of analysis to minimize
microbiological decomposition of solids. Preferably do not hold samples more than 24 hours.
Under no circumstances should the sample be held more than seven days. Bring samples to room
temperature before analysis.
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 ongoing analysis of laboratory reagent blanks, precision and recovery
standards, and matrix-spiked samples as a continuing check on performance. The laboratory is
required to maintain performance records that define the quality of data thus generated.
Laboratory performance is compared to established performance criteria to determine if the results
of analyses meet the performance characteristics of the method.
9.1.1 The analyst shall make an initial demonstration of the ability to generate acceptable
accuracy and precision with this method. This ability is established as described in
Section 9.2.
9.1.2 In recognition of advances that are occurring in analytical technology, the analyst is
permitted certain options to improve separations or lower the costs of measurements,
provided that all performance specifications are met. If an analytical technique other than
the techniques specified in this method is used, that technique must have a specificity equal
to or better than the specificity of the techniques in this method for total, fixed, and volatile
solids in the sample of interest. Specificity is defined as producing results equivalent to the
results produced by this method for laboratory-prepared solutions (Section 7.2) that meet
all of the QC criteria stated in this method.
9.1.2.1 Each time a modification is made to this method, the analyst is required to
repeat the Initial Precision and Recovery (IPR) test in Section 9.2.2 to
demonstrate that the modification produces results equivalent to or better
than results produced by this method. If the detection limit of the method
will be affected by the modification, the analyst must demonstrate that the
MDL (40 CFR part 136, appendix B) is less than or equal to the MDL in
this method or one-third the regulatory compliance level, whichever is
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Method 1684
higher. The tests required for this equivalency demonstration are given in
Section 9.2.
9.1.2.2 The laboratory is required to maintain records of modifications made to
this method. These records include the following, at a minimum:
9.1.2.2.1 The names, titles, addresses, and telephone numbers of the
analyst(s) who performed the analyses and modification, and of
the quality control officer who witnessed and will verify the
analyses and modification.
9.1.2.2.2 A listing of pollutant(s) measured (total, fixed, and volatile
solids).
9.1.2.2.3 A narrative stating reason(s) for the modification.
9.1.2.2.4 Results from all quality control (QC) tests comparing the
modified method to this method, including:
(a) Initial precision and recovery (Section 9.2.2).
(b) Analysis of blanks (Section 9.3).
(c) Accuracy assessment (Section 9.5).
(d) Ongoing precision and recovery (Section 9.4).
9.1.2.2.5 Data that will allow an independent reviewer to validate each
determination by tracing the instrument output (weight,
absorbance, or other signal) to the final result. These data are to
include:
(a) Sample numbers and other identifiers.
(b) Sample preparation dates.
(c) Analysis dates and times.
(d) Analysis sequence/run chronology.
(e) Sample weights.
(f) Make and model of analytical balance and weights
traceable to NIST.
(g) Copies of logbooks, printer tapes, and other recordings of
raw data.
(h) Data system outputs, and other data to link the raw data
to the results reported.
9.1.3 Analyses of laboratory blanks are required to demonstrate freedom from contamination.
The procedure and criteria for blank analyses are described in Section 9.3.
9.1.4 Analyses of ongoing precision and recovery (OPR) samples are required to demonstrate
that the sample preparation and analysis are in control. The procedure and criteria for
OPR samples are described in Section 9.4.
9.2 Initial demonstration of laboratory capability - The initial demonstration of laboratory capability is
used to characterize laboratory performance and method detection limits.
Draft-January 2001 5
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Method 1684
9.2.1 Method detection limit (MDL) - The method detection limit must be established for the
analyte, using the QC spiking solution (Section 7.2). To determine MDL values, take
seven replicate aliquots of the diluted QC spiking solution and process each aliquot
through each step of the analytical method. Perform all calculations and report the
concentration values in the appropriate units. MDLs should be determined every year or
whenever a modification to the method or analytical system is made that will affect the
method detection limit.
9.2.2 Initial Precision and Recovery (IPR) - To establish the ability to generate acceptable preci-
sion and accuracy, the analyst shall perform the following operations:
9.2.2.1 Prepare four samples by diluting the QC spiking solution (Section 7.2) to
1-5 times the ML. Using the procedures in Section 11, analyze these
samples for total, fixed, and volatile solids.
9.2.2.2 Using the results of the four analyses, compute the average percent recov-
ery (x) and the standard deviation (s, Equation 1) of the percent recovery
for total, fixed, and volatile solids.
Equation 1
.=
n-
Where:
n = number of samples
x = % recovery in each sample
s = standard deviation
9.2.2.3 Compare s and x with the corresponding limits for initial precision and
recovery in Table 1. If s and x meet the acceptance criteria, system
performance is acceptable and analysis of samples may begin. If,
however, s exceeds the precision limit or x falls outside the range for
recovery, system performance is unacceptable. In this event, correct the
problem, and repeat the test.
9.3 Laboratory blanks
9.3.1 Prepare and analyze a laboratory blank initially (i.e. with the tests in Section 9.2) and with
each analytical batch. The blank must be subjected to the same procedural steps as a
sample, and will consist of approximately 25 g of reagent water.
9.3.2 If material is detected in the blank at a concentration greater than the MDL (Section 1.3),
analysis of samples must be halted until the source of contamination is eliminated and a
new blank shows no evidence of contamination. All samples must be associated with an
uncontaminated laboratory blank before the results may be reported for regulatory compli-
ance purposes. Sample results are also acceptable for regulatory compliance purposes if
6 Draft-January 2001
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Method 1684
they are associated with a blank that contains less than 1/10 the concentration of the
analyte(s) of interest in the associated samples.
9.4 Ongoing Precision and Recovery (OPR).
9.4.1 Prepare an OPR solution identical to the IPR solution described in Section 9.2.2.1.
9.4.2 An aliquot of the OPR solution must be analyzed with each preparation batch (samples of
the same matrix started through the sample preparation process (Section 11) on the same
12-hour shift, to a maximum of 10 samples).
9.4.3 Compute the percent recovery of total, fixed, and volatile solids in the OPR sample.
9.4.4 For each analyte, compare the results to the limits for ongoing recovery in Table 1. If all
analytes meet the acceptance criteria, system performance is acceptable and analysis of
blanks and samples may proceed. If, however, the recovery of an analyte falls outside of
the range given, the analytical processes are not being performed properly for that analyte.
Correct the problem, reprepare the sample batch, and repeat the OPR test. All samples
must be associated with an OPR analysis that passes acceptance criteria before the sample
results can be reported for regulatory compliance purposes.
9.4.5 Add results that pass the specifications in Section 9.4.4 to IPR and previous OPR data.
Update QC charts to form a graphic representation of continued laboratory performance.
Develop a statement of laboratory accuracy for each analyte by calculating the average
percent recovery (R) and the standard deviation of percent recovery (SR). Express the
accuracy as a recovery interval from R-2SR to R+2SR. For example, if R=95% and
SR=5%, the accuracy is 85-105%.
9.5 Duplicate analyses
9.5.1 Ten percent of samples must be analyzed in duplicate. The duplicate analyses must be
performed within the same sample batch (samples whose analysis is started within the
same 12-hour period).
9.5.2 The results of duplicate samples analyzed for total, fixed, and volatile solids must be
within 10% of the solids determination.
10.0 Calibration and Standardization
10.1 Calibrate the analytical balance at 2 mg and 1000 mg using class "S" weights.
10.2 Calibration shall be within ± 10% (i.e. ±0.2 mg) at 2 mg and ± 0.5% (i.e. ±5 mg) at 1000 mg. If
values are not within these limits, recalibrate the balance.
10.3 Place a 50 g weight and a 2 mg on the balance. Verify that the balance reads 50.002 ±10 %
(i.e. ± 0.2 mg).
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Method 1684
11.0 Procedure
11.1 Total Solids
11.1.1 Preparation of evaporating dishes-If volatile solids are to be measured, ignite clean
evaporating dishes and watch glasses at 550°C for 1 hour in a muffle furnace. If only
total solids are to be measured, heat dishes and watch glasses at 103 °C to 105 °C for 1
hour in an oven. Cool and store the dried equipment in a desiccator. Weigh each dish and
watch glass prior to use (record combined weight as "Wdlsh").
11.1.2 Preparation of samples.
11.1.2.1 Fluid samples-If the sample contains enough moisture to flow readily, stir
to homogenize, place a 25 to 50 g sample aliquot on a prepared
evaporating dish. If the sample is to be analyzed in duplicate, the mass of
the two aliquots may not differ by more than 10%. Cover each sample
with a watch glass, and weigh to the nearest 0.01 g (record weight as
"Wsample"). Spread each sample so that it is evenly distributed over the
evaporating dish. Evaporate the samples to dryness on a steam bath.
NOTE: Weigh wet samples quickly because wet samples tend to lose weight by evaporation.
Samples should be weighed immediately after aliquots are prepared.
11.1.2.2 Solid samples-If the sample consists of discrete pieces of solid material
(dewatered sludge, for example), take cores from each piece with a No. 7
cork borer or pulverize the entire sample coarsely on a clean surface by
hand, using rubber gloves. Place a 25 to 50 g aliquot of the pulverized
sample on a prepared evaporating dish. If the sample is to be analyzed in
duplicate, the mass of the two aliquots may not differ by more than 10%.
Cover each sample with a watch glass, and weigh (record weight as
"Wsample"). Spread each sample so that it is evenly distributed over the
evaporating dish.
11.1.3 Dry the samples at 103 °C to 105 °C for 12 hours, minimum, cool to balance temperature
in an individual desiccator containing fresh desiccant, and weigh.
NOTE: It is imperative that dried samples be weighed quickly since residues often are very
hygroscopic and rapidly absorb moisture from the air. Samples must remain in the dessicator
until the analyst is ready to weigh them.
11.1.4 Heat the residue for 1 hour, cool it to balance temperature in a desiccator, and weigh.
Repeat this heating, cooling, desiccating, and weighing procedure until the weight change
is less than 4% or 50 mg, whichever is less. Record the final weight as "Wtotal."
11.2 Fixed and volatile solids.
11.2.1 Transfer the evaporating dishes containing the dried residues (Section 11.1.4) to a cool
muffle furnace. Heat the furnace to 550°C and ignite it for 2 hours.
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Method 1684
NOTE: If the residue contains large amounts of organic matter, first ignite it over a gas
burner and under an exhaust hood in the presence of adequate air to lessen losses due to
reducing conditions and to avoid odors in the laboratory.
11.2.2 Cool the residue in a desiccator to balance the temperature. Weigh the residues. Repeat
igniting (30 min), cooling, desiccating, and weighing steps until the weight change is less
than 4% or 50 mg, whichever is less. Record the final weight as "Wvolatlle."
12.0 Data Analysis and Calculations
12.1 Calculate the % solids or the mg solids/kg sludge for total solids (Equation 2), fixed solids,
(Equation 3), and volatile solids (Equation 4).
Equation 2
% total solids = —^ — * 100
"sample ~ "dish
or
mg total solids W. ., - W,.,
,—71, = u u * 1,000,000
kg sludge Wsample - Wdish
Where:
Wdlsh=Weightofdish (mg)
Wsample=Weight of wet sample and dish (mg)
Wtotai=Weight of dried residue and dish (mg)
Equation 3
W -W
% fixed solids = vo atl e ^— *
"total ~ "dish
or
mg fixed solids _ Wvolatlle - Wdlsh
kg sludge Wtotal-Wdlsh
Where:
* 1,000,000
Wdish=Weightofdish (mg)
Wtotal=Weight of dried residue and dish (mg)
Wvolatile=Weight of residue and dish after ignition (mg)
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Method 1684
Equation 4
W, ,-W, .,
% volatile solids = -^ v-2^ * 100
vv — vv
"'total "'dish
or
mg volatile solids _ Wtotal - Wvolatile ^
kg sludge Wtotal - Wdish
Where:
Wdlsh=Weightofdish (mg)
Wtotal=Weight of dried residue and dish (mg)
Wvoiatile=Weight of residue and dish after ignition (mg)
12.2 Sample results should be reported as % solids or mg/kg to three significant figures. Report results
below the ML as < ML, or as required by the permitting authority or in the permit. Duplicate
determinations must agree within 10% of their average.
13.0 Method Performance
13.1 Method performance (MDL and quality control acceptance criteria) will be determined during the
multi-lab validation of this method.
13.2 Total, fixed, and volatile solids duplicate determinations must agree within 10% to be reported for
permitting purposes. If duplicate samples do not meet this criteria, the problem must be discovered
and the sample must be run over.
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 Environmental Protection Agency has established a preferred hierarchy
of environmental 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
institutions, consult "Less is Better: Laboratory Chemical Management for Waste Reduction",
available from the American Chemical Society's Department of Government Relations 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
conducted be consistent with all applicable rules and regulations. The Agency urges laboratories
to protect the air, water, and land by minimizing and controlling all releases from hoods and bench
10 Draft-January 2001
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Method 1684
operations, complying with the letter and spirit of any sewer discharge permits and regulations, and
by complying with all solid and hazardous 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 the Section 14.2.
16.0 References
16.1 Goodman, B.L. 1964. Processing thickened sludge with chemical conditioners. Pages 78 et seq. in
Sludge Concentration, Filtration and Incineration. Univ. Michigan Continued Education Ser. No.
113, Ann Arbor.
16.2 Gratteau, J.C. & R.I. Dick. 1968. Activated sludge suspended solids determinations. Water
Sewage Works 115:468.
16.3 Theriault, E.J. & H.H. Wagenhals. 1923. Studies of representative sewage plants. Pub. Health
Bulletin. No. 132.
16.4 U.S. Environmental Protection Agency, 1979. Methods for Chemical Analysis of Water and
Wastes. Publ. 600/4-79-020, rev. March 1983. Environmental Monitoring and Support Lab., U.S.
Environmental Protection Agency, Cincinnati, Ohio.
16.5 "OSHA Safety and Health Standards, General Industry", (29CFR 1910), Occupational Safety and
Health Administration, OSHA 2206, revised January, 1976.
16.6 "Safety in Academic Chemistry Laboratories", American Chemical Society Publication,
Committee on Chemical Safety, 3rd Edition, 1979.
16.7 "Standard Methods for the Examination of Water and Wastewater," 18th ed. and later revisions,
American Public Health Association, 1015 15th Street NW, Washington, DC 20005. 1-35:
Section 1090 (Safety), 1992.
16.8 U.S. Environmental Protection Agency, 1992. Control of Pathogens and Vector Attraction in
Sewage Sludge. Publ 625/R-92/013. Office of Research and Development, Washington, DC.
16.9 "Handbook of Analytical Quality Control in Water and Wastewater Laboratories," USEPA,
EMSL-Ci, Cincinnati, OH 45268, EPA-600/4-79-019, March 1979.
16.10 "Environmental Regulations and Technology: Control of Pathogens and Vector Attraction in
Biosolid, " 1992. EPA/625/R-92/013. Office of Research and Development. USEPA.
17.0 Tables, Diagrams, Flowcharts, and Validation Data
17.1 Table 1 - Quality Control Acceptance Criteria for Method 1684.
Draft-January 2001 11
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Method 1684
18.0 Definitions
18.1 Analytical batch-The set of samples analyzed at the same time, to a maximum of 10 samples.
Each analytical batch of 10 or fewer samples must be accompanied by a laboratory blank (Section
9.3), an ongoing precision and recovery sample (OPR, Section 9.6), and a set of duplicate samples,
resulting in a minimum of five analyses (1 sample, 1 blank, 1 OPR, 2 duplicates) and a maximum
of 14 analyses.
18.2 Fixed solids-The residue left in the vessel after a sample is ignited (heated to dryness at 550°C).
18.3 Initial precision and recovery (IPR)-Four aliquots of the diluted PAR analyzed to establish the
ability to generate acceptable precision and accuracy. An IPR is performed the first time this
method is used and any time the method or instrumentation is modified.
18.4 IPR-See initial precision and recovery.
18.5 Laboratory blank (method blank)-An aliquot of reagent water that is treated exactly as a sample
including exposure to all glassware, equipment and reagents that are used with samples. The
laboratory blank is used to determine if analytes or interferences are present in the laboratory
environment, the reagents, or the apparatus.
18.6 Laboratory control sample (LCS)-See Ongoing precision and recovery standard (OPR).
18.7 May-This action, activity, or procedural step is neither required nor prohibited.
18.8 May not-This action, activity, or procedural step is prohibited.
18.9 Method detection limit (MDL)-The lowest level at which an analyte can be detected with 99 %
confidence that the analyte concentration is greater than zero.
18.10 Must-This action, activity, or procedural step is required.
18.11 Ongoing precision and recovery standard (OPR, also called a laboratory control sample)-A
laboratory blank spiked with known quantities of analytes. The OPR is analyzed exactly like a
sample. Its purpose is to assure that the results produced by the laboratory remain within the
limits specified in this method for precision and accuracy.
18.12 OPR-See Ongoing precision and recovery standard.
18.13 PAR-See Precision and recovery standard.
18.14 Precision and recovery standard-Secondary standard that is diluted and spiked to form the IPR and
OPR.
18.15 Quality control sample (QCS):-A sediment sample containing analytes of interest at known
concentrations. The QCS is obtained from a source external to the laboratory or is prepared from
standards obtained from a different source than the calibration standards. The purpose is to check
laboratory performance using test materials that have been prepared independently from the normal
preparation process.
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Method 1684
18.16 Reagent Water- Water that should be free of substances that interfere with analytical methods.
18.17 Sediment sample-A fluvial, sand and/or humic sample matrix exposed to a marine, brackish or
fresh water environment. It is limited by this method to that portion which may be passed through
a number 10 sieve or a 2 mm mesh sieve.
18.18 Shall-This action, activity or procedural step is required.
18.19 Should-This action, activity, or procedural step is suggested but not required.
18.20 Total solids-The residue left in the vessel after evaporation of liquid from a sample and subsequent
drying in an oven at 103°C to 105 °C.
18.21 Volatile solids-The weight loss after a sample is ignited (heated to dryness at 550°C).
Determinations of fixed and volatile solids do not distinguish precisely between inorganic and
organic matter because the loss on ignition is not confined to organic matter. It includes losses due
to decomposition or volatilization of some mineral salts.
Table 1 - Quality Control Acceptance Criteria for Method 16841
Analyte
total solids
fixed solids
volatile solids
MDL
3mg/L
7mg/L
7mg/L
IPR
X
85-110%
75-110%
75-110%
s
10%Rsd
20% Rsd
30% Rsd
OPR
X
80-110%
70-110%
70-110%
1 Performance criteria are initial estimates. These estimates serve as data quality objectives for the single laboratory validation
of this method.
Draft-January 2001
13
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