ASTM D6044-96(2009)
(Guide)Standard Guide for Representative Sampling for Management of Waste and Contaminated Media
Standard Guide for Representative Sampling for Management of Waste and Contaminated Media
SIGNIFICANCE AND USE
Representative samples are defined in the context of the study objectives.
This guide defines the meaning of a representative sample, as well as the attributes the sample(s) needs to have in order to provide a valid inference from the sample data to the population.
This guide also provides a process to identify the sources of error (both systematic and random) so that an effort can be made to control or minimize these errors. These sources include sampling error, measurement error, and statistical bias.
When the objective is limited to the taking of a representative (physical) sample or a representative set of (physical) samples, only potential sampling errors need to be considered. When the objective is to make an inference from the sample data to the population, additional measurement error and statistical bias need to be considered.
This guide does not apply to the cases where the taking of a nonrepresentative sample(s) is prescribed by the study objective. In that case, sampling approaches such as judgment sampling or biased sampling can be taken. These approaches are not within the scope of this guide.
Following this guide does not guarantee that representative samples will be obtained. But failure to follow this guide will likely result in obtaining sample data that are either biased or imprecise, or both. Following this guide should increase the level of confidence in making the inference from the sample data to the population.
This guide can be used in conjunction with the DQO process (see Practice D 5792).
This guide is intended for those who manage, design, and implement sampling and analytical plans for waste management and contaminated media.
SCOPE
1.1 This guide covers the definition of representativeness in environmental sampling, identifies sources that can affect representativeness (especially bias), and describes the attributes that a representative sample or a representative set of samples should possess. For convenience, the term“ representative sample” is used in this guide to denote both a representative sample and a representative set of samples, unless otherwise qualified in the text.
1.2 This guide outlines a process by which a representative sample may be obtained from a population. The purpose of the representative sample is to provide information about a statistical parameter(s) (such as mean) of the population regarding some characteristic(s) (such as concentration) of its constituent(s) (such as lead). This process includes the following stages: (1) minimization of sampling bias and optimization of precision while taking the physical samples, (2) minimization of measurement bias and optimization of precision when analyzing the physical samples to obtain data, and (3) minimization of statistical bias when making inference from the sample data to the population. While both bias and precision are covered in this guide, major emphasis is given to bias reduction.
1.3 This guide describes the attributes of a representative sample and presents a general methodology for obtaining representative samples. It does not, however, provide specific or comprehensive sampling procedures. It is the user's responsibility to ensure that proper and adequate procedures are used.
1.4 The assessment of the representativeness of a sample is not covered in this guide since it is not possible to ever know the true value of the population.
1.5 Since the purpose of each sampling event is unique, this guide does not attempt to give a step by step account of how to develop a sampling design that results in the collection of representative samples.
1.6 Appendix X1 contains two case studies, which discuss the factors for obtaining representative samples.
1.7 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 ...
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: D6044 − 96(Reapproved 2009)
Standard Guide for
Representative Sampling for Management of Waste and
1
Contaminated Media
This standard is issued under the fixed designation D6044; 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 1.6 Appendix X1 contains two case studies, which discuss
the factors for obtaining representative samples.
1.1 This guide covers the definition of representativeness in
1.7 This standard does not purport to address all of the
environmental sampling, identifies sources that can affect
safety concerns, if any, associated with its use. It is the
representativeness (especially bias), and describes the attri-
responsibility of the user of this standard to establish appro-
butes that a representative sample or a representative set of
priate safety and health practices and determine the applica-
samples should possess. For convenience, the term“ represen-
bility of regulatory limitations prior to use.
tative sample” is used in this guide to denote both a represen-
tative sample and a representative set of samples, unless
2. Referenced Documents
otherwise qualified in the text.
2
2.1 ASTM Standards:
1.2 This guide outlines a process by which a representative
D3370Practices for Sampling Water from Closed Conduits
samplemaybeobtainedfromapopulation.Thepurposeofthe
D4448GuideforSamplingGround-WaterMonitoringWells
representative sample is to provide information about a statis-
D4547Guide for Sampling Waste and Soils for Volatile
tical parameter(s) (such as mean) of the population regarding
Organic Compounds
some characteristic(s) (such as concentration) of its constitu-
D4700Guide for Soil Sampling from the Vadose Zone
ent(s) (such as lead). This process includes the following
D4823Guide for Core Sampling Submerged, Unconsoli-
stages: (1) minimization of sampling bias and optimization of
dated Sediments
precision while taking the physical samples, (2) minimization
D5088Practice for Decontamination of Field Equipment
of measurement bias and optimization of precision when
Used at Waste Sites
analyzing the physical samples to obtain data, and (3) minimi-
D5792Practice for Generation of Environmental Data Re-
zation of statistical bias when making inference from the
lated to Waste Management Activities: Development of
sample data to the population. While both bias and precision
Data Quality Objectives
are covered in this guide, major emphasis is given to bias
D5956Guide for Sampling Strategies for Heterogeneous
reduction.
Wastes
1.3 This guide describes the attributes of a representative
D6051Guide for Composite Sampling and Field Subsam-
sample and presents a general methodology for obtaining
pling for Environmental Waste Management Activities
representative samples. It does not, however, provide specific
or comprehensive sampling procedures. It is the user’s respon-
3. Terminology
sibilitytoensurethatproperandadequateproceduresareused.
3.1 analytical unit, n—the actual amount of the sample
1.4 The assessment of the representativeness of a sample is
material analyzed in the laboratory.
not covered in this guide since it is not possible to ever know
3.2 bias, n—a systematic positive or negative deviation of
the true value of the population.
the sample or estimated value from the true population value.
1.5 Sincethepurposeofeachsamplingeventisunique,this
3.2.1 Discussion—This guide discusses three sources of
guidedoesnotattempttogiveastepbystepaccountofhowto
bias—sampling bias, measurement bias, and statistical bias.
develop a sampling design that results in the collection of
There is a sampling bias when the value inherent in the
representative samples.
physical samples is systematically different from what is
inherent in the population.
1
This guide is under the jurisdiction of ASTM Committee D34 on Waste
Management and is the direct responsibility of Subcommittee D34.01.01 on
2
Planning for Sampling. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Feb. 1, 2009. Published March 2009. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1996. Last previous edition approved in 2003 as D6044–96(2003). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D6044-96R09. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
D6044 − 96 (2009)
There is a measurement bias when the measurement process presence of differe
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.