ASTM D1687-02(2007)e1
(Test Method)Standard Test Methods for Chromium in Water
Standard Test Methods for Chromium in Water
SIGNIFICANCE AND USE
Hexavalent chromium salts are used extensively in metal finishing and plating applications, in anodizing aluminum, and in the manufacture of paints, dyes, explosives, and ceramics. Trivalent chromium salts are used as mordants in textile dyeing, in the ceramic and glass industry, in the leather industry as a tanning agent, and in photography. Chromium may be present in wastewater from these industries and may also be discharged from chromate-treated cooling waters.
The hexavalent state of chromium is toxic to humans, animals, and aquatic life. It can produce lung tumors when inhaled and readily induces skin sensitization. However, it is not known whether cancer will result from ingestion of chromium in any of its valence states.
SCOPE
1.1 These test methods cover the determination of hexavalent and total chromium in water. Three test methods are included as follows:Test Method Concentration RangeSectionsA-Photometric Diphenyl- carbohydrazide0.01 to 0.5 mg/LB-Atomic Absorption, Direct0.1 to 10 mg/LC-Atomic Absorption, Graphite Furnace5 to 100 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 National Pollution Discharge Elimination System (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.
This standard does not purport to address all of the safety concerns, 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 hazard statements, see 4.2 and Note 5 and Note 6.
General Information
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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
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Designation: D1687 − 02(Reapproved 2007)
Standard Test Methods for
Chromium in Water
This standard is issued under the fixed designation D1687; 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 (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
´ NOTE—The table in 1.1 and Sections 15.5, 24.5, and 33.3 were updated editorially in August 2007.
1. Scope priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. For specific hazard
1.1 These test methods cover the determination of hexava-
statements, see 4.2 and Note 5 and Note 6.
lent and total chromium in water. Three test methods are
included as follows:
2. Referenced Documents
Test Method Concentration Sections
Range
2.1 ASTM Standards:
A—Photometric Diphenyl- 0.01 to 0.5 7-15
D858 Test Methods for Manganese in Water
carbohydrazide mg/L
D1066 Practice for Sampling Steam
B—Atomic 0.1to10 16-24
Absorption, Direct mg/L
D1068 Test Methods for Iron in Water
C—Atomic Absorption, 5to100 25-33
D1129 Terminology Relating to Water
Graphite Furnace µg/L
D1192 Guide for Equipment for Sampling Water and Steam
1.2 Test Method A is a photometric method that measures 3
in Closed Conduits (Withdrawn 2003)
dissolved hexavalent chromium only. Test Methods B and C
D1193 Specification for Reagent Water
are atomic absorption methods that are generally applicable to
D1688 Test Methods for Copper in Water
the determination of dissolved or total recoverable chromium
D1691 Test Methods for Zinc in Water
in water without regard to valence state.
D1886 Test Methods for Nickel in Water
1.3 Test Method A has been used successfully with reagent D2777 Practice for Determination of Precision and Bias of
grade water Types I, II, and III, tap water, 10 % NaCl solution, Applicable Test Methods of Committee D19 on Water
treated water from a synthetic organic industrial plant that
D3370 Practices for Sampling Water from Closed Conduits
meets National Pollution Discharge Elimination System D3557 Test Methods for Cadmium in Water
(NPDES) permit requirements, and EPA-extraction procedure
D3558 Test Methods for Cobalt in Water
leachate water, process water, lake water, effluent treatment, D3559 Test Methods for Lead in Water
that is, lime neutralization and precipitation of spent pickle
D3919 Practice for Measuring Trace Elements in Water by
liquor and associated rinse water from stainless steel pickling. Graphite Furnace Atomic Absorption Spectrophotometry
Test Method C has been used successfully with reagent water,
D4691 Practice for Measuring Elements in Water by Flame
stock scrubber water, lake water, filtered tap water, river water, Atomic Absorption Spectrophotometry
well water, production plant water, and a condensate from a
D4841 Practice for Estimation of Holding Time for Water
medium BTU coal gasification process. Matrices used, except Samples Containing Organic and Inorganic Constituents
for reagent water, are not available for Test Method B. It is the
D5810 Guide for Spiking into Aqueous Samples
user’sresponsibilitytoensurethevalidityofthesetestmethods D5847 Practice for Writing Quality Control Specifications
for waters of untested matrices. for Standard Test Methods for Water Analysis
E60 Practice for Analysis of Metals, Ores, and Related
1.4 This standard does not purport to address all of the
Materials by Spectrophotometry
safety concerns, if any, associated with its use. It is the
E275 Practice for Describing and Measuring Performance of
responsibility of the user of this standard to establish appro-
1 2
These test methods are under the jurisdiction of ASTM Committee D19 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Water and are the direct responsibility of Subcommittee D19.05 on Inorganic contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Constituents in Water. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Aug. 1, 2007. Published August 2007. Originally the ASTM website.
approved in 1959. Last previous edition approved in 2002 as D1687 – 02. DOI: The last approved version of this historical standard is referenced on
10.1520/D1687-02R07E01. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
D1687 − 02 (2007)
Ultraviolet and Visible Spectrophotometers immediately. Minor delays in stabilization or analyses of
samples containing sulfur reduction compounds can produce
3. Terminology
significant loss in hexavalent chromium. Acidic samples con-
3.1 Definitions—For definitions of terms used in these test taining hypobromite, persulfate, or chlorine could oxidize
trivalent chromium, if present, to hexavalent form upon pres-
methods, refer to Terminology D1129.
ervation, resulting in a positive interference. When the pres-
3.2 Definitions of Terms Specific to This Standard:
ence of these oxidizing compounds is suspected, samples
3.2.1 Laboratory Control Sample, n—a solution with the
should not be preserved but analyzed immediately. It will be
certified concentration(s) of the analytes.
evident that in this case, the simultaneous presence of reducing
compounds could not be anticipated.
4. Significance and Use
4.1 Hexavalent chromium salts are used extensively in 6.3 Samples to be analyzed by Test Methods B and C shall
be preserved by addition of HNO (sp gr 1.42) to pH of 2 or
metal finishing and plating applications, in anodizing alumi-
num, and in the manufacture of paints, dyes, explosives, and lessimmediatelyatthetimeofcollection,normallyabout2mL
ceramics. Trivalent chromium salts are used as mordants in HNO /L. If only dissolved chromium is to be determined, the
textile dyeing, in the ceramic and glass industry, in the leather sample shall be filtered through a 0.45-µm membrane filter
industry as a tanning agent, and in photography. Chromium before acidification.
may be present in wastewater from these industries and may
TEST METHOD A—PHOTOMETRIC
also be discharged from chromate-treated cooling waters.
DIPHENYLCARBOHYDRAZIDE
4.2 The hexavalent state of chromium is toxic to humans,
animals, and aquatic life. It can produce lung tumors when
7. Scope
inhaled and readily induces skin sensitization. However, it is
7.1 This test method covers the determination of dissolved
not known whether cancer will result from ingestion of
hexavalent chromium in water.
chromium in any of its valence states.
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.
Unless otherwise indicated, it is intended that all reagents shall
7.3 This test method has been used successfully with
conform to the specifications of the Committee on Analytical
4 reagent grade water Types I, II, and III, tap water, 10 % NaCl
Reagents of the American Chemical Society where such
solution, treated water from a synthetic organic industrial plant
specifications are available. Other grades may be used, pro-
that meets NPDES permit requirements, EPA-extraction pro-
vided it is first ascertained that the reagent is of sufficiently
cedure leachate water, process water, lake water, effluent from
high purity to permit its use without lessening the accuracy of
treatment that is, lime neutralization and precipitation of spent
the determination.
pickle liquor and associated rinse water from stainless steel
5.2 Purity of Water—Unless otherwise indicated, references
pickling. It is the responsibility of the user to ensure the
towatershallbeunderstoodtomeanreagentwaterconforming
validity of the test method to waters of untested matrices.
to Specification D1193, Type I, II, or III water. Type I is
preferred and more commonly used. Type II water was
8. Summary of Test Method
specified at the time of round robin testing of these test
8.1 Hexavalent chromium reacts with 1.5-
methods.
diphenylcarbohydrazide (s-diphenylcarbazide) in an acid me-
NOTE 1—The user must ensure the type of reagent water chosen is
dium to produce a reddish-purple color. The intensity of the
sufficiently free of interferences. The water should be analyzed using the
color formed is proportional to the hexavalent chromium
test method.
concentration.
6. Sampling
9. Interferences
6.1 Collect the sample in accordance with the applicable
ASTM standard as follows: Practice D1066, Specification
9.1 Vanadium, titanium, or iron present at concentrations of
D1192, or Practices D3370. The holding time for the samples
5 mg/Lyield a 10 to 30 % reduction in recovery of chromium.
may be calculated in accordance with Practice D4841.
Copper at 100 mg/L yields a 20 to 30 % reduction in recovery
in the presence of sulfate. Mercury gives a blue-purple color,
6.2 Samples to be analyzed by Test Method A should be
butthereactionisnotverysensitiveatthepHemployedforthe
stabilized upon collection by addition of sodium hydroxide
test.
solution to a pH greater than or equal to 8, or analyzed
9.2 Nitriteconcentrationsinexcessof10mg/LasNO yield
lowtestresults.Sulfamicacidmaybeadded(;10.1g)priorto
Reagent Chemicals, American Chemical Society Specifications , American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
the addition of diphenylcarbazide solution to minimize nitrite
listed by the American Chemical Society, see Analar Standards for Laboratory
interference. Add sulfamic acid only when the presence of
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
nitrite has been positively established. Excess sulfamic acid
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
MD. itself creates a slightly positive interference.
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D1687 − 02 (2007)
9.3 Sulfide and sulfite reduce chromate in an acid medium 12.3 Prepare a calibration curve by plotting milligrams per
to give low results. liter of chromium versus absorbance on linear graph paper.
9.4 Several sample matrices have been identified which
12.4 Acalibration curve must be prepared for each photom-
produce a yellow-orange complex that interferes with this eter. A recalibration must be made if any alterations of the
quantification. When this occurs, it may be remedied by
instrument are made or if new reagents are prepared. At the
inverting the indicator-buffer sequence. In these cases the least, a blank and three chromium standard solutions must be
analyst should evaluate the matrix effect with the additions of
analyzedtoverifytheoriginaltestcalibrationeachtimethetest
spikes. (Guide D5810) is performed.
9.5 Althougheachinterferenthasbeenreported,mostofthe
13. Procedure
common interferences are eliminated by the preservation
procedure at the time of collection. The potentially interfering
13.1 Filter a portion of the sample through a 0.45-µm
metals are precipitated and the reducing effect of sulfur
membrane filter and adjust the pH into the 8 to 8.5 range if it
compounds has been overcome.
is greater than 8.5 with a few drops of the phosphoric acid
solution (1 + 19).
10. Apparatus
13.2 Transfer 50.0 mL of the filtered sample, or a smaller
10.1 Photometer—Spectrophotometer or filter photometer
aliquot of sample diluted to 50.0 mL, to a 125-mLErlenmeyer
suitable for use at 540 nm and equipped with a cell having a
flask.
minimum path length of 10 mm. The photometers and photo-
13.3 Add 2.0 mL of the diphenylcarbazide solution to each
metric practice prescribed in this test method shall conform to
solution and swirl to mix.
Practice E60. Spectrophotometers and spectrophotometric
practice shall conform to Practice E275.
NOTE 3—If the sample is colored, prepare a separate aliquot as
described in 13.1 and 13.2. Add 2.0 mL of acetone instead of diphenyl-
11. Reagents carbazidesolutionandproceedwith13.4and13.5.Usethissolutionasthe
sample blank.
11.1 Chromium Solution, Stock (1 mL = 0.10 mg Cr)—
13.4 Immediately add 5.0 mL of phosphoric acid solution
Dissolve 0.2828 g of potassium dichromate (K Cr O that has
2 2 7
(1 + 1) to each solution and swirl to mix.
been oven dried at 105°C for 1 h) in water. Dilute to 1 L with
water.
13.5 Permit the solutions to stand 15 min for full color
development. Measure the absorbance within 30 min after the
11.2 Chromium Solution, Standard (1 mL = 0.001 mg Cr)—
addition of the diphenylcarbazide solution at 540 nm with a
Dilute 10.0 mL of chromium stock solution (see 11.1)to1L
cell having a minimum path length of 10 mm.
with water.
+6
13.6 Determine milligrams per liter of chromium as Cr in
11.3 Diphenylcarbazide Indicator Solution—Dissolve 0.25
the test sample by referring the absorbance to the prepared
g of powdered 1,5-diphenylcarbohydrazide in 100 mL of
calibration curve (see 12.3).
acetone. Store in an amber glass-stoppered flask at 4°C when
notinuse.Thissolutionisstableforaboutoneweekwhenkept
14. Calculation
refrigerated. Prepare fresh reagent when the solution becomes
discolored.
14.1 Calculate the hexavalent chromium concentration as
NOTE 2—Allow the indicator solution to warm to room temperature follows:
before use.
Cr , mg/L 5 W 2 W 50/S (1)
~ !~ !
S B
11.4 Phosphoric Acid (1+1)—Dilute 500 mL of concen-
where:
trated phosphoric acid (sp gr 1.69) to 1 L with water.
W = chromium found in the sample, mg/L (see 13.6),
S
11.5 Phosphoric Acid (1 + 19)—Dilute 50 mL of concen-
W = chromium found in the sample blank, mg/L (see
B
trated phosphoric acid (sp gr 1.69) to 1 L with water.
13.6), and
11.6 Sodium Hydroxide Solution (40 mg/L)—Dissolve 40
S = volume of sample used, mL (see 13.2).
mg of sodium hydroxide (NaOH) in water. Cool and dilute to
1 L. This solution is used for sample preservation.
15. Precision and Bias
11.7 Sulfamic Acid(NH SO H)—Crystals.
15.1 The collaborative test data were obtained on reagent
2 3
grade water Types I, II, and III, tap water, 10 % NaCl solution,
12. Calibration
treated water from a synthetic organic industrial plant which
12.1 Prepare a series of at least four standard solutions meets NPDES permit requirements, EPA-extraction procedure
leachate water, process water, lake water, effluent from treat-
containing from 0 to 0.50 mg/L of chromium by diluting
measured volumes of the standard chromium solution (see ment, that is, lime neutralization and precipitation of spent
pickle liquor and associated rinse water from stainless steel
11.2) to 100 mL with water in separate volumetric fla
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