ASTM D1687-92(1996)
(Test Method)Standard Test Methods for Chromium in Water
Standard Test Methods for Chromium in Water
SCOPE
1.1 These test methods cover the determination of hexavalent and total chromium in water. Three test methods are included. Concentration Sections Range Test Method A---Photometric Diphenyl- 0.01 to 0.5 7 to 15 carbohydrazide mg/L Test Method B---Atomic Absorption, Di- 0.1 to 10 16 to 24 rect mg/L Test Method C---Atomic Absorption, 5 to 100 25 to 33 Graphite Furnace [mu]g/L
1.2 Test Method A is a photometric method that measures dissolved hexavalent chromium only. Test Methods B and C are atomic absorption methods that are generally applicable to the determination of dissolved or total recoverable chromium in water without regard to valence state.
1.3 Test Method A has been used successfully with reagent grade water Types I, II, and III, tap water, 10% NaCl solution, treated water from a synthetic organic industrial plant that meets NPDES permit requirements, and EPA-extraction procedure leachate water, process water, lake water, effluent treatment, that is, lime neutralization and precipitation of spent pickle liquor and associated rinse water from stainless steel pickling. Test Method C has been used successfully with reagent water, stock scrubber water, lake water, filtered tap water, river water, well water, production plant water, and a condensate from a medium BTU coal gasification process. Matrices used, except for reagent water, are not available for Test Method B. It is the user's responsibility to ensure the validity of these test methods for waters of untested matrices.
1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. >For specific precautionary statements, see 4.2 and Note 5.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or
withdrawn. Contact ASTM International (www.astm.org) for the latest information.
Designation: D 1687 – 92 (Reapproved 1996)
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Methods for
Chromium in Water
This standard is issued under the fixed designation D 1687; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense. Consult the DoD Index of Specifications and
Standards for the specific year of issue which has been adopted by the Department of Defense.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 These test methods cover the determination of hexava-
D 858 Test Methods for Manganese in Water
lent and total chromium in water. Three test methods are
D 1066 Practice for Sampling Steam
included as follows:
D 1068 Test Methods for Iron in Wate
D 1129 Terminology Relating to Water
Concentration Sections
D 1192 Specification for Equipment for Sampling Water
Range
Test Method A—Photometric Diphenyl- 0.01 to 0.5 7-15
and Steam in Closed Conduits
carbohydrazide mg/L
D 1193 Specification for Reagent Water
Test Method B—Atomic Absorption, Di- 0.1 to 10 16-24
D 1688 Test Methods for Copper in Water
rect mg/L
Test Method C—Atomic Absorption, 5to100 25-33
D 1691 Test Methods for Zinc in Water
Graphite Furnace μg/L
D 1886 Test Methods for Nickel in Water
D 3370 Practices for Sampling Water from Closed Con-
1.2 Test Method A is a photometric method that measures
duits
dissolved hexavalent chromium only. Test Methods B and C
D 3557 Test Methods for Cadmium in Water
are atomic absorption methods that are generally applicable to
D 3558 Test Methods for Cobalt in Water
the determination of dissolved or total recoverable chromium
D 3559 Test Methods for Lead in Water
in water without regard to valence state.
D 4691 Practice for Measuring Elements in Water by Flame
1.3 Test Method A has been used successfully with reagent
Atomic Absorption Spectrophotometry
grade water Types I, II, and III, tap water, 10 % NaCl solution,
D 4841 Practice for Estimation of Holding Time for Water
treated water from a synthetic organic industrial plant that
Samples Containing Organic and Inorganic Constituents
meets NPDES permit requirements, and EPA-extraction pro-
E 60 Practice for Photometric and Spectrophotometric
cedure leachate water, process water, lake water, effluent
Methods for Chemical Analyses of Metals
treatment, that is, lime neutralization and precipitation of spent
E 275 Practice for Describing and Measuring Performance
pickle liquor and associated rinse water from stainless steel
of Ultraviolet, Visible, and Near Infrared Spectrophotom-
pickling. Test Method C has been used successfully with
eters
reagent water, stock scrubber water, lake water, filtered tap
3. Terminology
water, river water, well water, production plant water, and a
condensate from a medium BTU coal gasification process.
3.1 Definitions: —For definitions of terms used in these test
Matrices used, except for reagent water, are not available for
methods, refer to Terminology D 1129.
Test Method B. It is the user’s responsibility to ensure the
4. Significance and Use
validity of these test methods for waters of untested matrices.
4.1 Hexavalent chromium salts are used extensively in
1.4 This standard does not purport to address all of the
metal finishing and plating applications, in anodizing alumi-
safety concerns, if any, associated with its use. It is the
num, and in the manufacture of paints, dyes, explosives, and
responsibility of the user of this standard to establish appro-
ceramics. Trivalent chromium salts are used as mordants in
priate safety and health practices and determine the applica-
textile dyeing, in the ceramic and glass industry, in the leather
bility of regulatory limitations prior to use. For specific hazard
industry as a tanning agent, and in photography. Chromium
statements, see 4.2 and Note 5 and Note 6.
may be present in wastewater from these industries and may
also be discharged from chromate-treated cooling waters.
These test methods are under the jurisdiction of ASTM Committee D-19 on
Water and are the direct responsibility of Subcommittee D19.05 on Inorganic
Constituents in Water. Annual Book of ASTM Standards, Vol 11.01.
Current edition approved May 15, 1992. Published September 1992. Originally Annual Book of ASTM Standards, Vol 03.05.
published as D 1687 – 59 T. Last previous edition D 1687 – 86. Annual Book of ASTM Standards, Vol 03.06.
D 1687
4.2 The hexavalent state of chromium is toxic to humans, TEST METHOD A—PHOTOMETRIC
animals, and aquatic life. It can produce lung tumors when DIPHENYLCARBOHYDRAZIDE
inhaled and readily induces skin sensitization. However, it is
7. Scope
not known whether cancer will result from ingestion of
7.1 This test method covers the determination of dissolved
chromium in any of its valence states.
hexavalent chromium in water.
7.2 The test method is applicable in the range from 0.01 to
5. Purity of Reagents
0.5 mg/L chromium. The range may be extended by appropri-
5.1 Reagent grade chemicals shall be used in all tests. ate sample dilution.
7.3 This test method has been used successfully with
Unless otherwise indicated, it is intended that all reagents shall
reagent grade water Types I, II, and III, tap water, 10 % NaCl
conform to the specifications of the Committee on Analytical
solution, treated water from a synthetic organic industrial plant
Reagents of the American Chemical Society where such
that meets NPDES permit requirements, EPA-extraction pro-
specifications are available. Other grades may be used, pro-
cedure leachate water, process water, lake water, effluent from
vided it is first ascertained that the reagent is of sufficiently
treatment that is, lime neutralization and precipitation of spent
high purity to permit its use without lessening the accuracy of
pickle liquor and associated rinse water from stainless steel
the determination.
pickling. It is the responsibility of the user to ensure the
5.2 Purity of Water—Unless otherwise indicated, references
validity of the test method to waters of untested matrices.
to water shall be understood to mean reagent water conforming
8. Summary of Test Method
to Specification D 1193, Type I, II, or III water. Type I is
preferred and more commonly used. Type II water was
8.1 Hexavalent chromium reacts with 1.5-
specified at the time of round-robin testing of these test
diphenylcarbohydrazide (s-diphenylcarbazide) in an acid me-
methods.
dium to produce a reddish-purple color. The intensity of the
color formed is proportional to the hexavalent chromium
NOTE 1—The user must ensure the type of reagent water chosen is
concentration.
sufficiently free of interferences. The water should be analyzed using the
test method.
9. Interferences
9.1 Vanadium, titanium, or iron present at concentrations of
6. Sampling
5 mg/L yield a 10 to 30 % reduction in recovery of chromium.
6.1 Collect the sample in accordance with the applicable Copper at 100 mg/L yields a 20 to 30 % reduction in recovery
ASTM standard as follows: Practice D 1066, Specification in the presence of sulfate. Mercury gives a blue-purple color,
but the reaction is not very sensitive at the pH employed for the
D 1192, or Practices D 3370. The holding time for the samples
test.
may be calculated in accordance with Practice D 4841.
9.2 Nitrite concentrations in excess of 10 mg/L as NO yield
6.2 Samples to be analyzed by Test Method A should be
low test results. Sulfamic acid may be added (;10.1 g) prior to
stabilized upon collection by addition of sodium hydroxide
the addition of diphenylcarbazide solution to minimize nitrite
solution to a pH greater than or equal to 8, or analyzed
interference. Add sulfamic acid only when the presence of
immediately. Minor delays in stabilization or analyses of
nitrite has been positively established. Excess sulfamic acid
samples containing sulfur reduction compounds can produce
itself creates a slightly positive interference.
significant loss in hexavalent chromium. Acidic samples con-
9.3 Sulfide and sulfite reduce chromate in an acid medium
taining hypobromite, persulfate, or chlorine could oxidize
to give low results.
trivalent chromium, if present, to hexavalent form upon pres-
9.4 Several sample matrices have been identified which
ervation, resulting in a positive interference. When the pres-
produce a yellow-orange complex which interferes with this
ence of these oxidizing compounds is suspected, samples
quantification. When this occurs, it may be remedied by
should not be preserved but analyzed immediately. It will be
inverting the indicator-buffer sequence. In these cases the
evident that in this case, the simultaneous presence of reducing
analyst should evaluate the matrix effect with the additions of
compounds could not be anticipated.
spikes.
6.3 Samples to be analyzed by Test Methods B and C shall
9.5 Although each interferent has been reported, most of the
be preserved by addition of HNO (sp gr 1.42) to pH of 2 or less common interferences are eliminated by the preservation
immediately at the time of collection, normally about 2 mL procedure at the time of collection. The potentially interfering
metals are precipitated and the reducing effect of sulfur
HNO /L. If only dissolved chromium is to be determined, the
sample shall be filtered through a 0.45-μm membrane filter compounds has been overcome.
before acidification.
10. Apparatus
10.1 Photometer—Spectrophotometer or filter photometer
suitable for use at 540 nm and equipped with a cell having a
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
minimum path length of 10 mm. The photometers and photo-
listed by the American Chemical Society, see Analar Standards for Laboratory
metric practice prescribed in this test method shall conform to
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Practice E 60. Spectrophotometers and spectrophotometric
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
MD. practice shall conform to Practice E 275.
D 1687
11. Reagents 13.5 Permit the solutions to stand 15 min for full color
development. Measure the absorbance within 30 min after the
11.1 Chromium Solution, Stock (1 mL 5 0.10 mg Cr)—
addition of the diphenylcarbazide solution at 540 nm with a
Dissolve 0.2828 g of potassium dichromate (K Cr O that has
2 2 7
cell having a minimum path length of 10 mm.
been oven dried at 105°C for 1 h) in water. Dilute to 1 L with
+6
13.6 Determine milligrams per litre of chromium as Cr in
water.
the test sample by referring the absorbance to the prepared
11.2 Chromium Solution, Standard (1 mL 5 0.001 mg
calibration curve (see 12.3).
Cr)—Dilute 10.0 mL of chromium stock solution (see 11.1) to
1 L with water.
14. Calculation
11.3 Diphenylcarbazide Indicator Solution—Dissolve 0.25
14.1 Calculate the hexavalent chromium concentration as
g of powdered 1,5-diphenylcarbohydrazide in 100 mL of
follows:
acetone. Store in an amber glass-stoppered flask at 4°C when
not in use. This solution is stable for about one week when kept
Cr , mg/L 5 ~W 2 W !~50/S! (1)
S B
refrigerated. Prepare fresh reagent when the solution becomes
where:
discolored.
W 5 chromium found in the sample, mg/L (see 13.6),
S
NOTE 2—Allow the indicator solution to warm to room temperature
W 5 chromium found in the sample blank, mg/L (see
B
before use.
13.6), and
11.4 Phosphoric Acid (1 + 1)—Dilute 500 mL of concen-
S 5 volume of sample used, mL (see 13.2).
trated phosphoric acid (sp gr 1.69) to 1 L with water.
15. Precision and Bias
11.5 Phosphoric Acid (1 + 19)—Dilute 50 mL of concen-
trated phosphoric acid (sp gr 1.69) to 1 L with water.
15.1 The collaborative test data were obtained on reagent
11.6 Sodium Hydroxide Solution (40 mg/L)—Dissolve 40
grade water Types I, II, and III, tap water, 10 % NaCl solution,
mg of sodium hydroxide (NaOH) in water. Cool and dilute to
treated water from a synthetic organic industrial plant which
1 L. This solution is used for sample preservation.
meets NPDES permit requirements, EPA-extraction procedure
11.7 Sulfamic Acid(NH SO H)—Crystals.
leachate water, process water, lake water, effluent from
2 3
treatment, that is, lime neutralization and precipitation of spent
12. Calibration
pickle liquor and associated rinse water from stainless steel
12.1 Prepare a series of at least four standard solutions
pickling.
containing from 0 to 0.50 mg/L of chromium by diluting
15.2 Single-operator and overall precision of this test
measured volumes of the standard chromium solution (see
method within its designated range and recovery data for the
11.2) to 100 mL with water in separate volumetric flasks.
above waters for 16 laboratories, which include a total of 16
12.2 Transfer 50 mL of each prepared standard solution to
operators analyzing each sample on three different days, is
separate 125-mL Erlenmeyer flasks and proceed with 13.3-
given in Table 1.
13.6.
15.3 Single-operator and overall precision of this test
12.3 Prepare a calibration curve by plotting milligrams per
method within its designated range and recovery data for a
litre of chromium versus absorbance on linear graph paper.
prepared leachate water for 8 laboratories, which include a
12.4 A calibration curve must be prepared for each photom-
total of 8 operators analyzing each sample on three different
eter. A recalibration must be made if any alterations of the
days, is also given in Table 1.
instrument are made or if new reagents are prepared. At the
15.4 It is the user’s responsibility to ensure the validity of
least, a blank and three chromium standard solutions must be
the test method for waters of untested matrices.
analyzed to verify the original test calibration each time the test
is performed.
TEST METHOD B—ATOMIC ABSORPTION,
DIRECT
13. Procedure
13.1 Filter a portion of the sample through a 0.45-μm 16. Scope
membrane filter and adjust the pH into the 8 to 8.5 range if it
16.1 This test method covers the determination of dissolved
is greater than 8.5 with a few drops of the phosphoric acid
and total recoverable chromium in most waters, wastewaters,
solution (1 + 19).
and brines.
13.2 Transfer 50.0 mL of the filtered sample, or a smaller
16.2 The test method is applicable in the range from 0.1 to
aliquot of sample
...
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