ASTM D3974-81(1999)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 3974 – 81 (Reapproved 1999)
Standard Practices for
Extraction of Trace Elements from Sediments
This standard is issued under the fixed designation D 3974; 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.
1. Scope responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
1.1 These practices describe the partial extraction of soils,
bility of regulatory limitations prior to use.
bottom sediments, suspended sediments, and waterborne ma-
terials to determine the extractable concentrations of certain
2. Referenced Documents
trace elements.
2.1 ASTM Standards:
1.1.1 Practice A is capable of extracting concentrations of
D 887 Practice for Sampling Water-Formed Deposits
aluminum, boron, barium, cadmium, calcium, chromium, co-
D 1129 Terminology Relating to Water
balt, copper, iron, lead, magnesium, manganese, molybdenum,
D 1193 Specification for Reagent Water
nickel, potassium, sodium, strontium, vanadium, and zinc from
the preceding materials. Other metals may be determined using
3. Terminology
this practice. This extraction is the more vigorous and more
3.1 Refer to Terminology D 1129.
complicated of the two.
1.1.2 Practice B is capable of extracting concentrations of
4. Summary of Practices
aluminum, cadmium, chromium, cobalt, copper, iron, lead,
4.1 The chemical portion of both practices involves acid
manganese, nickel, and zinc from the preceding materials.
digestion to disassociate the elements complexed in precipi-
Other metals may be determined using this practice. This
tated hydroxides, carbonates, sulfides, oxides, and organic
extraction is less vigorous and less complicated than Practice
materials. Surface but not interstitially bound elements will be
A.
desorbed in the case of clay mineral particulates. The silicate
1.2 These practices describe three means of preparing
lattices of the minerals are not appreciably attacked (1-5).
samples prior to digestion:
4.2 These practices provide samples suitable for analysis
1.2.1 Freeze-drying.
using flame or flameless atomic-absorption spectrophotometry,
1.2.2 Air-drying at room temperature.
or other instrumental or colorimetric procedures.
1.2.3 Accelerated air-drying, for example, 95°C.
1.3 The detection limit and linear concentration range of
5. Significance and Use
each procedure for each element is dependent on the atomic
5.1 Industrialized and urban areas have been found to
absorption spectrophotometric or other technique employed
deposit a number of toxic elements into environments where
and may be found in the manual accompanying the instrument
those elements were previously either not present or were
used. Also see various ASTM test methods for determining
found in trace amounts. Consequently, it is important to be able
specific metals using atomic absorption spectrophotometric
to measure the concentration of these pollution-deposited
techniques.
elements to properly study pollution effects.
1.3.1 The sensitivity of the practice can be adjusted by
5.2 This procedure is concerned with the pollution-related
varying the sample size (14.2) or the dilution of the sample
trace elements that are described in 4.1 rather than those
(14.6), or both.
elements incorporated in the silicate lattices of the minerals
1.4 Extractable trace element analysis provides more infor-
from which the sediments were derived. These pollution-
mation than total metal analysis for the detection of pollutants,
related trace elements are released into the water and read-
since absorption, complexation, and precipitation are the meth-
sorbed by the sediments with changes in general water quality,
ods by which metals from polluted waters are retained in
pH in particular. These elements are a serious source of
sediments.
pollution. The elements locked in the silicate lattices are not
1.5 This standard does not purport to address all of the
readily available in the biosphere (1-8).
safety concerns, if any, associated with its use. It is the
1 2
These practices are under the jurisdiction of ASTM Committee D-19 on Water Annual Book of ASTM Standards, Vol 11.02.
and are the direct responsibility of Subcommittee D19.07 on Sediments, Geomor- Annual Book of ASTM Standards, Vol 11.01.
phology, and Open-Channel Flow. The boldface numbers in parentheses refer to the references at the end of these
Current edition approved March 2, 1981. Published May 1981. practices.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 3974
5.3 Caution—when comparing the trace element concen- D 1193, Type II. The water shall be free of metallic contami-
trations, it is important to consider the particle sizes to be nants.
analyzed (8, 9). 8.3 Hydrochloric Acid (sp gr 1.19)—Concentrated hydro-
5.3.1 The finer the particle the greater the surface area. chloric acid (HCl). The acid must be low in metallic ions.
Consequently, a potentially greater amount of a given trace 8.4 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
element can be adsorbed on the surface of fine, particulate (HNO ). The acid must be low in metallic ions.
samples (4). For particle sizes smaller than 80 mesh, metal 8.5 Metal Solutions, Stock—Prepare metal stock solutions,
content is no longer dependent on surface area. Therefore, if each containing 1000 mg/L of a metal of interest and either
this portion of the sediment is used, the analysis with respect to negligible or known concentrations of interfering metals.
sample type (that is, sand, salt, or clay) is normalized. It has
9. Precautions
also been observed that the greatest contrast between anoma-
9.1 Digest the samples only in a laboratory ventilation hood.
lous and background samples is obtained when less than
80-mesh portion of the sediment is used (4, 5).
10. Sampling
5.3.2 After the samples have been dried, care must be taken
10.1 Collect the sediments using an appropriate technique
not to grind the sample in such a way to alter the natural
(see Practice D 887).
particle-size distribution (14.1). Fracturing a particle disrupts
10.2 Retain and store that portion of sediment which passes
the silicate lattice and makes available those elements which
through a nylon, 10-mesh sieve, 1-mm particle size (5.3).
otherwise are not easily digested (6). Normally, aggregates of
10.3 Store the sample in plastic bags or plastic bottles that
dried, natural soils, sediments, and many clays dissociate once
the reagents are added (14.3 and 15.2). can be tightly sealed. Immediately pack and cool the samples
for shipping.
6. Interferences
10.4 Store samples at 4°C if analysis is to be performed
6.1 The only interferences are those encountered in the final
within 1 week. Otherwise, store the samples at − 20°C until
determination of metals using atomic-absorption spectropho-
analyzed.
tometry or other instrumental or colorimetric procedures.
11. Glassware Cleaning
7. Apparatus
11.1 Immerse all glassware and implements in a hot solution
7.1 Digestion Beakers—Use only beakers made of borosili-
of HCl (1 + 1) for 3 to 5 min.
cate glass or TFE-fluorocarbons.
11.2 Second, immerse all glassware and implements in
7.2 Watchglasses— Use ribbed watchglasses to cover the
HNO (1 + 1) for 3 to 5 min.
digestion beakers. These covers should fit loosely to allow
11.3 Rinse all glassware and implements repeatedly with
evaporation of the digestion medium.
water following the acid washes.
7.3 Filter Paper— The qualitative grade paper employed
should be a fast filtering, hardened, ashless paper retaining both 12. Sample Preparation
coarse and gelatinous precipitates.
12.1 Completely thaw
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