ASTM D3974-81(2008)
(Practice)Standard Practices for Extraction of Trace Elements from Sediments
Standard Practices for Extraction of Trace Elements from Sediments
SIGNIFICANCE AND USE
Industrialized and urban areas have been found to deposit a number of toxic elements into environments where those elements were previously either not present or were found in trace amounts. Consequently, it is important to be able to measure the concentration of these pollution-deposited elements to properly study pollution effects.
This procedure is concerned with the pollution-related trace elements that are described in 4.1 rather than those elements incorporated in the silicate lattices of the minerals from which the sediments were derived. These pollution-related trace elements are released into the water and readsorbed by the sediments with changes in general water quality, pH in particular. These elements are a serious source of pollution. The elements locked in the silicate lattices are not readily available in the biosphere (1-8).
When comparing the trace element concentrations, it is important to consider the particle sizes to be analyzed (8, 9).
The finer the particle the greater the surface area. Consequently, a potentially greater amount of a given trace element can be adsorbed on the surface of fine, particulate samples (4). For particle sizes smaller than 80 mesh, metal content is no longer dependent on surface area. Therefore, if this portion of the sediment is used, the analysis with respect to sample type (that is, sand, salt, or clay) is normalized. It has also been observed that the greatest contrast between anomalous and background samples is obtained when less than 80-mesh portion of the sediment is used (4, 5).
After the samples have been dried, care must be taken not to grind the sample in such a way to alter the natural particle-size distribution (14.1). Fracturing a particle disrupts the silicate lattice and makes available those elements which otherwise are not easily digested (6). Normally, aggregates of dried, natural soils, sediments, and many clays dissociate once the reagents are added (14.3 and 15.2).
SCOPE
1.1 These practices describe the partial extraction of soils, bottom sediments, suspended sediments, and waterborne materials to determine the extractable concentrations of certain trace elements.
1.1.1 Practice A is capable of extracting concentrations of aluminum, boron, barium, cadmium, calcium, chromium, cobalt, copper, iron, lead, magnesium, manganese, molybdenum, nickel, potassium, sodium, strontium, vanadium, and zinc from the preceding materials. Other metals may be determined using this practice. This extraction is the more vigorous and more complicated of the two.
1.1.2 Practice B is capable of extracting concentrations of aluminum, cadmium, chromium, cobalt, copper, iron, lead, manganese, nickel, and zinc from the preceding materials. Other metals may be determined using this practice. This extraction is less vigorous and less complicated than Practice A.
1.2 These practices describe three means of preparing samples prior to digestion:
1.2.1 Freeze-drying.
1.2.2 Air-drying at room temperature.
1.2.3 Accelerated air-drying, for example, 95°C.
1.3 The detection limit and linear concentration range of each procedure for each element is dependent on the atomic absorption spectrophotometric or other technique employed and may be found in the manual accompanying the instrument used. Also see various ASTM test methods for determining specific metals using atomic absorption spectrophotometric techniques.
1.3.1 The sensitivity of the practice can be adjusted by varying the sample size (14.2) or the dilution of the sample (14.6), or both.
1.4 Extractable trace element analysis provides more information than total metal analysis for the detection of pollutants, since absorption, complexation, and precipitation are the methods by which metals from polluted waters are retained in sediments.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This...
General Information
Relations
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:D3974–81 (Reapproved 2008)
Standard Practices for
Extraction of Trace Elements from Sediments
This standard is issued under the fixed designation D3974; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.5 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
1.1 These practices describe the partial extraction of soils,
standard.
bottom sediments, suspended sediments, and waterborne ma-
1.6 This standard does not purport to address all of the
terials to determine the extractable concentrations of certain
safety concerns, if any, associated with its use. It is the
trace elements.
responsibility of the user of this standard to establish appro-
1.1.1 Practice A is capable of extracting concentrations of
priate safety and health practices and determine the applica-
aluminum, boron, barium, cadmium, calcium, chromium, co-
bility of regulatory limitations prior to use.
balt, copper, iron, lead, magnesium, manganese, molybdenum,
nickel,potassium,sodium,strontium,vanadium,andzincfrom
2. Referenced Documents
theprecedingmaterials.Othermetalsmaybedeterminedusing
2.1 ASTM Standards:
this practice. This extraction is the more vigorous and more
D887 Practices for Sampling Water-Formed Deposits
complicated of the two.
D1129 Terminology Relating to Water
1.1.2 Practice B is capable of extracting concentrations of
D1193 Specification for Reagent Water
aluminum, cadmium, chromium, cobalt, copper, iron, lead,
manganese, nickel, and zinc from the preceding materials.
3. Terminology
Other metals may be determined using this practice. This
3.1 Refer to Terminology D1129.
extraction is less vigorous and less complicated than Practice
A.
4. Summary of Practices
1.2 These practices describe three means of preparing
4.1 The chemical portion of both practices involves acid
samples prior to digestion:
digestion to disassociate the elements complexed in precipi-
1.2.1 Freeze-drying.
tated hydroxides, carbonates, sulfides, oxides, and organic
1.2.2 Air-drying at room temperature.
materials. Surface but not interstitially bound elements will be
1.2.3 Accelerated air-drying, for example, 95°C.
desorbed in the case of clay mineral particulates. The silicate
1.3 The detection limit and linear concentration range of
lattices of the minerals are not appreciably attacked (1-5).
each procedure for each element is dependent on the atomic
4.2 These practices provide samples suitable for analysis
absorption spectrophotometric or other technique employed
usingflameorflamelessatomic-absorptionspectrophotometry,
and may be found in the manual accompanying the instrument
or other instrumental or colorimetric procedures.
used. Also see various ASTM test methods for determining
specific metals using atomic absorption spectrophotometric
5. Significance and Use
techniques.
5.1 Industrialized and urban areas have been found to
1.3.1 The sensitivity of the practice can be adjusted by
deposit a number of toxic elements into environments where
varying the sample size (14.2) or the dilution of the sample
those elements were previously either not present or were
(14.6), or both.
foundintraceamounts.Consequently,itisimportanttobeable
1.4 Extractable trace element analysis provides more infor-
to measure the concentration of these pollution-deposited
mation than total metal analysis for the detection of pollutants,
elements to properly study pollution effects.
sinceabsorption,complexation,andprecipitationarethemeth-
5.2 This procedure is concerned with the pollution-related
ods by which metals from polluted waters are retained in
trace elements that are described in 4.1 rather than those
sediments.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
These practices are under the jurisdiction ofASTM Committee D19 on Water contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
and are the direct responsibility of Subcommittee D19.07 on Sediments, Geomor- Standards volume information, refer to the standard’s Document Summary page on
phology, and Open-Channel Flow. the ASTM website.
Current edition approved Oct. 1, 2008. Published November 2008. Originally The boldface numbers in parentheses refer to the references at the end of these
´1
approved in 1981. Last previous edition approved in 2003 as D3974–81 (2003) . practices.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D3974–81 (2008)
elements incorporated in the silicate lattices of the minerals indicated,allreagentsshallconformtothespecificationsofthe
from which the sediments were derived. These pollution- Committee onAnalytical Reagents of theAmerican Chemical
related trace elements are released into the water and read- Society.
sorbed by the sediments with changes in general water quality, 8.2 Purity of Water—References to water shall be under-
pH in particular. These elements are a serious source of stood to mean reagent water conforming to Specification
pollution. The elements locked in the silicate lattices are not D1193, Type II. The water shall be free of metallic contami-
readily available in the biosphere (1-8). nants.
8.3 Hydrochloric Acid (sp gr 1.19)—Concentrated hydro-
5.3 When comparing the trace element concentrations, it is
chloric acid (HCl). The acid must be low in metallic ions.
important to consider the particle sizes to be analyzed (8, 9).
8.4 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
5.3.1 The finer the particle the greater the surface area.
(HNO ). The acid must be low in metallic ions.
Consequently, a potentially greater amount of a given trace
8.5 Metal Solutions, Stock—Prepare metal stock solutions,
element can be adsorbed on the surface of fine, particulate
each containing 1000 mg/L of a metal of interest and either
samples (4). For particle sizes smaller than 80 mesh, metal
negligible or known concentrations of interfering metals.
content is no longer dependent on surface area. Therefore, if
thisportionofthesedimentisused,theanalysiswithrespectto
9. Precautions
sample type (that is, sand, salt, or clay) is normalized. It has
9.1 Digestthesamplesonlyinalaboratoryventilationhood.
also been observed that the greatest contrast between anoma-
lous and background samples is obtained when less than
10. Sampling
80-mesh portion of the sediment is used (4, 5).
10.1 Collect the sediments using an appropriate technique
5.3.2 After the samples have been dried, care must be taken
(see Practice D887).
not to grind the sample in such a way to alter the natural
10.2 Retain and store that portion of sediment which passes
particle-size distribution (14.1). Fracturing a particle disrupts
through a nylon, 10-mesh sieve, 1-mm particle size (5.3).
the silicate lattice and makes available those elements which
10.3 Store the sample in plastic bags or plastic bottles that
otherwise are not easily digested (6). Normally, aggregates of
can be tightly sealed. Immediately pack and cool the samples
dried, natural soils, sediments, and many clays dissociate once
for shipping.
the reagents are added (14.3 and 15.2).
10.4 Store samples at 4°C if analysis is to be performed
within 1 week. Otherwise, store the samples at−20°C until
6. Interferences analyzed.
6.1 Theonlyinterferencesarethoseencounteredinthefinal
11. Glassware Cleaning
determination of metals using atomic-absorption spectropho-
11.1 Immerseallglasswareandimplementsinahotsolution
tometry or other instrumental or colorimetric procedures.
of HCl (1+1) for 3 to 5 min.
11.2 Second, immerse all glassware and implements in
7. Apparatus
HNO (1+1) for 3 to 5 min.
7.1 Diges
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.