ASTM D2972-15(2023)
(Test Method)Standard Test Methods for Arsenic in Water
Standard Test Methods for Arsenic in Water
SIGNIFICANCE AND USE
4.1 Herbicides, insecticides, and many industrial effluents contain arsenic and are potential sources of water pollution. Arsenic is significant because of its adverse physiological effects on humans.
SCOPE
1.1 These test methods2 cover the photometric and atomic absorption determination of arsenic in most waters and wastewaters. Three test methods are given as follows:
Concentration
Range
Sections
Test Method A—Silver Diethyldithio-
carbamate Colorimetric
5 μg/L to 250 μg/L
7 to 16
Test Method B—Atomic Absorption,
Hydride Generation
1 μg/L to 20 μg/L
17 to 26
Test Method C—Atomic Absorption,
Graphite Furnace
5 μg/L to 100 μg/L
27 to 36
1.2 The analyst should direct attention to the precision and bias statements for each test method. It is the user's responsibility to ensure the validity of these test methods for waters of untested matrices.
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard.
1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see 11.1 and 20.2.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D2972 − 15 (Reapproved 2023)
Standard Test Methods for
Arsenic in Water
This standard is issued under the fixed designation D2972; 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.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 These test methods cover the photometric and atomic
D1129 Terminology Relating to Water
absorption determination of arsenic in most waters and waste-
D1193 Specification for Reagent Water
waters. Three test methods are given as follows:
D2777 Practice for Determination of Precision and Bias of
Concentration Sections
Applicable Test Methods of Committee D19 on Water
Range
Test Method A—Silver Diethyldithio- 5 μg ⁄L to 250 μg ⁄L 7 to 16 D3370 Practices for Sampling Water from Flowing Process
carbamate Colorimetric
Streams
Test Method B—Atomic Absorption, 1 μg ⁄L to 20 μg/L 17 to 26
D3919 Practice for Measuring Trace Elements in Water by
Hydride Generation
Test Method C—Atomic Absorption, 5 μg ⁄L to 100 μg/L 27 to 36
Graphite Furnace Atomic Absorption Spectrophotometry
Graphite Furnace
D4841 Practice for Estimation of Holding Time for Water
Samples Containing Organic and Inorganic Constituents
1.2 The analyst should direct attention to the precision and
D5810 Guide for Spiking into Aqueous Samples
bias statements for each test method. It is the user’s responsi-
D5673 Test Method for Elements in Water by Inductively
bility to ensure the validity of these test methods for waters of
Coupled Plasma—Mass Spectrometry
untested matrices.
D5847 Practice for Writing Quality Control Specifications
1.3 The values stated in SI units are to be regarded as
for Standard Test Methods for Water Analysis
standard. The values given in parentheses are mathematical
E60 Practice for Analysis of Metals, Ores, and Related
conversions to inch-pound units that are provided for informa-
Materials by Spectrophotometry
tion only and are not considered standard.
E275 Practice for Describing and Measuring Performance of
Ultraviolet and Visible Spectrophotometers
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3. Terminology
responsibility of the user of this standard to establish appro-
3.1 Definitions:
priate safety, health, and environmental practices and deter-
3.1.1 For definitions of terms used in these test methods,
mine the applicability of regulatory limitations prior to use.
refer to Terminology D1129.
For specific hazard statements, see 11.1 and 20.2.
3.2 Definitions of Terms Specific to This Standard:
1.5 This international standard was developed in accor-
3.2.1 total recoverable arsenic, n—a descriptive term relat-
dance with internationally recognized principles on standard-
ing to the arsenic forms recovered in the acid-digestion
ization established in the Decision on Principles for the
procedure specified in these test methods.
Development of International Standards, Guides and Recom-
3.2.1.1 Discussion—Some organic-arsenic compounds,
mendations issued by the World Trade Organization Technical
such as phenylarsonic acid, disodium methane arsonate, and
Barriers to Trade (TBT) Committee. dimethylarsonic acid, are not recovered completely during the
digestion step.
4. Significance and Use
These test methods are under the jurisdiction of ASTM Committee D19 on
4.1 Herbicides, insecticides, and many industrial effluents
Water and are the direct responsibility of Subcommittee D19.05 on Inorganic
contain arsenic and are potential sources of water pollution.
Constituents in Water.
Current edition approved Dec. 1, 2023. Published December 2023. Originally
Arsenic is significant because of its adverse physiological
approved in 1993. Last previous edition approved in 2015 as D2972 – 15. DOI:
effects on humans.
10.1520/D2972-15R23.
Similar to that appearing in Standard Methods for the Examination of Water
and Wastewater, 12th edition, APHA, Inc., New York, NY, 1965; and identical with For referenced ASTM standards, visit the ASTM website, www.astm.org, or
that in Brown, E., Skougstad, M. W., and Fishman, M. J., “Methods for Collection contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
and Analysis of Water Samples for Dissolved Minerals and Gases,” Techniques of Standards volume information, refer to the standard’s Document Summary page on
Water-Resources Investigations of the U.S. Geological Survey, Book 5, 1970, p. 46. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2972 − 15 (2023)
5. Purity of Reagents stannous chloride, and finally to gaseous arsine by zinc in
hydrochloric acid solution. The resulting mixture of gases is
5.1 Reagent grade chemicals shall be used in all tests.
passed through a scrubber containing borosilicate wool im-
Unless otherwise indicated, it is intended that all reagents shall
pregnated with lead acetate solution and then into an absorp-
conform to the specifications of the Committee on Analytical
tion tube containing a solution of silver diethyldithiocarbamate
Reagents of the American Chemical Society, where such
in pyridine. Arsine reacts with this reagent to form a red-
specifications are available. Other grades may be used, pro-
colored silver sol having maximum absorbance at about
vided it is first ascertained that the reagent is of sufficiently
540 nm. The absorbance of the solution is measured photo-
high purity to permit its use without lessening the accuracy of
metrically and the arsenic determined by reference to an
the determination.
analytical curve prepared from standards.
5.2 Purity of Water—Unless otherwise indicated, references
to water shall be understood to mean reagent water conforming
9. Interferences
to Specification D1193, Type I. Other reagent water types may
9.1 Although many samples are relatively free of
be used provided it is first ascertained that the water is of
interferences, several metals, notably cobalt, nickel, mercury,
sufficiently high purity to permit its use without adversely
silver, platinum, copper, chromium, and molybdenum, may
affecting the bias and precision of the test method. Type II
interfere with the evolution of arsine and with the recovery of
water was specified at the time of round robin testing of these
arsenic. The presence of any or all of these metals in a sample
test methods.
being analyzed must be considered as a potential source of
interference, and the analyst must fully determine the extent of
6. Sampling
actual interference, if any. This could be accomplished by
6.1 Collect the sample in accordance with Practices D3370.
spiking.
6.2 Preserve the samples with HNO (sp gr 1.42) to a pH of
9.2 Hydrogen sulfide and other sulfides interfere, but com-
2 or less immediately at the time of collection; normally about
monly encountered quantities are effectively removed by the
2 mL/L is required. If only dissolved arsenic is to be
lead acetate scrubber and the digestion.
determined, filter the sample through a 0.45 μm membrane
9.3 Antimony interferes by forming stibine, which distills
filter before acidification. The holding times for the samples
along with the arsine. Stibine reacts with the color-forming
may be calculated in accordance with Practice D4841.
reagent to form a somewhat similar red sol having maximum
NOTE 1—Alternatively, the pH may be adjusted in the laboratory if the
absorbance near 510 nm. The sensitivity for antimony at
sample is returned within 14 days. However, acid must be added at least
540 nm is only about 8 % that of arsenic (1 mg/L of antimony
24 h before analysis to dissolve any metals that adsorb to the container
will show an apparent presence of 0.08 mg/L of arsenic).
walls. This could reduce hazards of working with acids in the field when
appropriate.
9.4 Nitric acid interferes with the test and must be com-
pletely eliminated during the digestion.
TEST METHOD A—SILVER
DIETHYLDITHIOCARBAMATE COLORIMETRIC
10. Apparatus
7. Scope
10.1 Arsine Generator, Scrubber, and Absorber, assembled
7.1 This test method covers the determination of dissolved
as shown in Fig. 1.
and total recoverable arsenic in most waters and waste waters
10.2 Spectrophotometer or Filter Photometer, suitable for
in the range from 5 μg ⁄L to 250 μg ⁄L of arsenic.
use at 540 nm and providing a light path of at least 10 mm. The
7.2 The precision and bias data were obtained on reagent
filter photometer and photometric practice prescribed in this
water, river water, and process water. The information on
method shall conform to Practice E60. The spectrophotometer
precision and bias may not apply to other waters. It is the user’s
shall conform to Practice E275.
responsibility to ensure the validity of this test method for
waters of untested matrices.
11. Reagents and Materials
11.1 Arsenic Solution, Stock (1.00 mL = 1.00 mg As)—
8. Summary of Test Method
Commercially purchase or dissolve 1.320 g of arsenic trioxide
8.1 Organic arsenic-containing compounds are decomposed
(As O ) (Warning—Arsenic trioxide is extremely toxic. Avoid
2 3
by adding sulfuric and nitric acids and repeatedly evaporating
ingestion or inhalation of dry powder during standard prepa-
the sample to fumes of sulfur trioxide. The arsenic (V) so
ration. Wash hands thoroughly immediately after handling
produced, together with inorganic arsenic originally present, is
arsenic trioxide. Under no circumstances pipette any arsenic
subsequently reduced to arsenic (III) by potassium iodide and
solutions by mouth.), dried for at least 1 h at 110 °C, in 10 mL
of NaOH solution (420 g/L) and dilute to 1 L with water. This
solution is stable. A purchased arsenic stock solution of
ACS Reagent Chemicals, Specifications and Procedures for Reagents and
appropriate known purity is acceptable.
Standard-Grade Reference Materials, American Chemical Society, Washington,
DC. For suggestions on the testing of reagents not listed by the American Chemical
Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
copeial Convention, Inc. (USPC), Rockville, MD. Available commercially.
D2972 − 15 (2023)
11.9 Potassium Iodide Solution (150 g/L)—Dissolve 15 g of
potassium iodide (KI) in 100 mL of water. Store in an amber
bottle.
11.10 Silver Diethyldithiocarbamate Solution—Dissolve 1 g
of silver diethyldithiocarbamate (AgDDC) in 200 mL of
pyridine. This solution is stable for at least several months
when stored in an amber bottle.
11.11 Sodium Hydroxide Solution (420 g/L)—Dissolve 42 g
of sodium hydroxide (NaOH) pellets in 100 mL of water.
(Warning—This is a very exothermic reaction.)
11.12 Stannous Chloride Solution—Dissolve 40 g of
arsenic-free stannous chloride (SnCl ·2H O) in 100 mL of HCl
2 2
(sp gr 1.19). Add a few small pieces of mossy tin (which is the
common name and is commercially available).
11.13 Sulfuric Acid (1 + 1)—Cautiously, and with constant
stirring and cooling, add 250 mL of concentrated H SO (sp gr
2 4
1.84) to 250 mL of water.
11.14 Zinc, Granular, 20-mesh. Arsenic content must not
−6
exceed 1 × 10 %.
12. Standardization
12.1 Clean all glassware before use by rinsing first with hot
HNO (1 + 1) (11.7) and then with water. The absorbers must
be additionally rinsed with acetone and then air-dried.
12.2 Prepare, in a 250 mL generator flask, a blank and
sufficient standards containing from 0.0 μg to 25.0 μg of
arsenic by diluting 0.0 mL to 25.0 mL portions of the arsenic
standard solution to approximately 100 mL with water. Ana-
lyze at least five or more working standards containing
FIG. 1 Arsine Generator, Scrubber, and Absorber
concentrations of arsenic to define the nonlinear curve that
bracket the expected sample concentration, prior to analysis of
samples, to calibrate the instrument. A higher order of the curve
11.2 Arsenic Solution, Intermediate (1.00 mL = 10.0 μg
may be necessary.
As)—Dilute 5.00 mL of arsenic stock solution to 500 mL with
12.3 Proceed as directed in 13.3 – 13.9.
water.
12.4 Read directly the concentration or prepare an analytical
11.3 Arsenic Solution, Standard (1.00 mL = 1.00 μg As)—
curve by plotting the absorbances of standards versus micro-
Dilute 10.0 mL of arsenic intermediate solution to 100 mL with
grams of arsenic.
water. Prepare fresh before each use.
NOTE 2—The response is linear up to 15 μg of arsenic; however,
11.4 Filter Paper—Purchase suitable filter paper. Typically
because the curve is nonlinear above 15 μg, it is necessary to have
the filter papers have a pore size of 0.45 μm membrane.
sufficient standards above 15 μg to permit constructing an accurate curve.
Material such as fine-textured, acid-washed, ashless paper, or
glass fiber paper are acceptable. The user must first ascertain
13. Procedure
that the filter paper is of sufficient purity to use without
13.1 Clean all glassware before use by rinsing first with hot
adversely affecting the bias and precision of the test method.
HNO (1 + 1) (11.8) and then with water. The absorbers must
11.5 Hydrochloric Acid (sp gr 1.19)—Concentrated hydro-
be additionally rinsed with acetone and then air-dried.
chloric acid (HCl). Use analytical grade acid with an arsenic
13.2 Pipette a volume of well-mixed acidified sample con-
−6
content not greater than 1 × 10 %.
taining less than 25 μg of arsenic (100 mL maximum) into a
11.6 Lead Acetate Solution (100 g/L)—Dissolve 10 g of lead
generating flask and dilute to approximately 100 mL.
acetate (Pb(C H O ) ·3H O) in 100 mL of water. Store reagent
2 3 2 2 2
NOTE 3—If only dissolved arsenic is to be determined use a filtered
in a tightly stoppered container.
(11.4) and acidified sample (see 6.2).
11.7 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
13.3 To each flask, add 7 mL of H SO (1 + 1) (11.13) and
2 4
(HNO ). Use analytical grade acid with an arsenic content not
5 mL of concentrated HNO (11.7) (sp gr 1.42). Add a small
−6
greater than 1 × 10 %.
boiling chip and carefully evaporate to dense fumes of SO ,
11.8 Nitric Acid (1 + 1)—Add 250 mL of concentrated nitric maintaining an excess of HNO until all organic matter is
acid (sp gr 1.42) to 250 mL of water. destroyed. This prevents darkening of the solution and possible
D2972 − 15 (2023)
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