ASTM D6850-18

Standard Guide for QC of Screening Methods in Water

SIGNIFICANCE AND USE
4.1 Screening methods are often used to determine the presence or absence of a specific analyte, groups of analytes, classes of compounds or other indicators of chemical compounds in order to determine if further analysis or action is necessary. The determination whether to proceed with further action is useful in reducing the number of negative results for which the screening method serves as a surrogate.  
4.2 The use of screening methods, whether to generate qualitative or semi-quantitative results, is increasingly becoming a useful tool for regulatory monitoring, process control, and site characterization. The appropriate use of a screening method, or any other method for that matter, is dependent upon the data quality objectives (DQOs) that are defined by the user of the data.  
4.3 Persons responsible for assessing the quality of the data generated by the use of screening methods should have detailed QC guidelines by which to assess data quality.
SCOPE
1.1 This guide covers general considerations for the quality control (QC) practices for use with screening methods for organic and inorganic constituents in water. Methods are provided by various standard setting bodies, governmental agencies, as well as many domestic and international manufacturers.  
1.2 This guide provides general QC procedures that are applicable to a broad range of screening methodologies. These procedures help to ensure the quality of data that is generated. Additional, method-specific or project specific requirements may be necessary. This guide also includes general considerations regarding proper utilization of screening methods.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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.  
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

• Status: Published
• Publication Date: 30-Apr-2018
• ICS: 19.100 - Non-destructive testing
• Technical Committee: D19 - Water
• Drafting Committee: D19.05 - Inorganic Constituents in Water

Relations

• Replaces: ASTM D6850-13 - Standard Guide for QC of Screening Methods in Water
• Effective Date: 01-May-2018
• Refers: ASTM D1129-13(2020)e2 - Standard Terminology Relating to Water
• Effective Date: 01-May-2020
• Refers: ASTM D4840-99(2018)e1 - Standard Guide for Sample Chain-of-Custody Procedures
• Effective Date: 15-Aug-2018
• Refers: ASTM D5172-91(2015) - Standard Guide for Documenting the Standard Operating Procedures Used for the Analysis of Water (Withdrawn 2024)
• Effective Date: 15-Dec-2015
• Refers: ASTM D5905-98(2013) - Standard Practice for the Preparation of Substitute Wastewater
• Effective Date: 01-Jan-2013
• Refers: ASTM D1129-10 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2010
• Refers: ASTM D5172-91(2010)e1 - Standard Guide for Documenting the Standard Operating Procedures Used for the Analysis of Water
• Effective Date: 01-Feb-2010
• Refers: ASTM D4840-99(2010) - Standard Guide for Sampling Chain-of-Custody Procedures
• Effective Date: 01-Feb-2010
• Refers: ASTM D5905-98(2008) - Standard Practice for the Preparation of Substitute Wastewater
• Effective Date: 15-Jul-2008
• Refers: ASTM D1129-06ae1 - Standard Terminology Relating to Water
• Effective Date: 01-Sep-2006
• Refers: ASTM D1129-06a - Standard Terminology Relating to Water
• Effective Date: 01-Sep-2006
• Refers: ASTM D1193-06 - Standard Specification for Reagent Water
• Effective Date: 01-Mar-2006
• Refers: ASTM D1129-06 - Standard Terminology Relating to Water
• Effective Date: 15-Feb-2006
• Refers: ASTM D1129-04e1 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2004
• Refers: ASTM D1129-04 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2004

Overview

ASTM D6850-18: Standard Guide for Quality Control (QC) of Screening Methods in Water provides comprehensive guidelines for implementing quality control practices in screening methods used to test organic and inorganic constituents in water. These screening methods serve as essential tools for determining the presence or absence of specific analytes or classes of compounds and support rapid decision-making regarding the need for further analysis. The guide addresses both qualitative and semi-quantitative testing strategies and is widely applicable across laboratory, field, regulatory, and industrial contexts. This standard is instrumental in ensuring reliable, reproducible, and defensible results that meet defined data quality objectives (DQOs).

Key Topics

• Scope and Applicability
  ASTM D6850-18 outlines general QC practices for a variety of water screening methodologies, covering both organic and inorganic components. The guidance extends to methods established by standard-setting bodies, governmental agencies, and manufacturers.

• Data Quality Objectives (DQOs)
  The standard highlights the necessity for clear DQOs, which dictate the selection and application of appropriate screening and QC methods.

• Quality Control Procedures
  Recommended practices include:

  • Running method blanks and standards with each batch of samples.
  • Analyzing duplicate samples to verify reproducibility.
  • Demonstrating analyst proficiency through documented procedures.
  • Conducting calibration, matrix spike, precision, bias, and false positive/negative studies according to method type.

• Types of Screening Methods
  This guide distinguishes among:

  • Qualitative methods (detecting presence/absence of analytes),
  • Semi-quantitative methods Type 1 (results reported in defined concentration ranges),
  • Semi-quantitative methods Type 2 (results reported as a numeric value with associated uncertainty).

• Validation and Documentation
  Emphasis is placed on method validation, comparison to reference methods, inter-laboratory comparison, and maintaining robust standard operating procedures (SOPs).

Applications

ASTM D6850-18 enhances the reliability of water screening by standardizing QC protocols, making it valuable for:

• Regulatory Monitoring
  Supporting compliance with water quality regulations by ensuring accurate detection of contaminants.
• Environmental Site Assessment
  Characterizing water for the presence of pollutants or hazardous substances, informing risk assessments and remediation decisions.
• Process Control
  Assisting industrial facilities in monitoring process water and effluents, protecting assets, and meeting operational standards.
• Field Testing
  Guiding the selection and QC of portable screening methods for rapid, on-site decision-making.
• Laboratory Quality Assurance
  Establishing consistent batch QC, analyst training, and method validation protocols to meet audit and accreditation requirements.

Related Standards

Several ASTM standards complement ASTM D6850-18, supporting comprehensive water testing and QC systems:

• ASTM D1129: Terminology Relating to Water
• ASTM D1193: Specification for Reagent Water
• ASTM D4840: Guide for Sample Chain-of-Custody Procedures
• ASTM D5172: Guide for Documenting Standard Operating Procedures Used for the Analysis of Water
• ASTM D5847: Practice for Writing Quality Control Specifications for Standard Test Methods for Water Analysis
• ASTM D5905: Practice for the Preparation of Substitute Wastewater

In addition, the principles outlined in ASTM D6850-18 align with international standardization policies and facilitate harmonized approaches to water quality testing worldwide.

Keywords: ASTM D6850-18, quality control, screening methods, water testing, qualitative analysis, semi-quantitative, data quality objectives, QC procedures, laboratory quality assurance.

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: D6850 − 18
Standard Guide for
QC of Screening Methods in Water
This standard is issued under the fixed designation D6850; 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* D5172 Guide for Documenting the Standard Operating Pro-
cedures Used for the Analysis of Water
1.1 This guide covers general considerations for the quality
D5847 Practice for Writing Quality Control Specifications
control (QC) practices for use with screening methods for
for Standard Test Methods for Water Analysis
organic and inorganic constituents in water. Methods are
D5905 Practice for the Preparation of Substitute Wastewater
provided by various standard setting bodies, governmental
agencies, as well as many domestic and international manu-
3. Terminology
facturers.
3.1 Definitions:
1.2 This guide provides general QC procedures that are
3.1.1 For definitions of terms used in this standard, refer to
applicable to a broad range of screening methodologies. These
Terminology D1129 and Practice D5847.
procedures help to ensure the quality of data that is generated.
3.2 Definitions of Terms Specific to This Standard:
Additional, method-specific or project specific requirements
3.2.1 action level, n—a concentration of the analyte of
may be necessary. This guide also includes general consider-
concern at which some further action is required or suggested.
ations regarding proper utilization of screening methods.
3.2.2 batch, n—a set (group) of samples analyzed along
1.3 The values stated in SI units are to be regarded as
with QC samples; the quality of the sample-set’s results is
standard. No other units of measurement are included in this
indicated by the results from the QC samples.
standard.
3.2.2.1 Discussion—The number of samples in the batch is
1.4 This standard does not purport to address all of the
defined by the task group responsible for the method. See
safety concerns, if any, associated with its use. It is the
PracticeD5847fordefinitionanddiscussionofbatchandbatch
responsibility of the user of this standard to establish appro-
size.
priate safety, health, and environmental practices and deter-
3.2.3 false negative, n—a negative response for a sample
mine the applicability of regulatory limitations prior to use.
that contains the target analyte(s) at or above the stated action
1.5 This international standard was developed in accor-
level.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the 3.2.4 false positive, n—a positive response for a sample that
Development of International Standards, Guides and Recom- contains the target analyte(s) below the stated action level.
mendations issued by the World Trade Organization Technical
3.2.5 qualitative method, n—a validated method that detects
Barriers to Trade (TBT) Committee.
presence or absence of an analyte at a specified screening limit.
3.2.6 screening limit, n—the concentration of analyte that
2. Referenced Documents
can be determined with a given certainty.
2.1 ASTM Standards:
3.2.6.1 Discussion—The task group responsible for the
D1129 Terminology Relating to Water
method establishes the value of the screening limit.
D1193 Specification for Reagent Water
3.2.7 screening method, n—amethodthatisusedtoseparate
D4840 Guide for Sample Chain-of-Custody Procedures
or categorize samples.
3.2.7.1 Discussion—An example would be a method that
1 provides results that would be used to separate samples into:
This guide is under the jurisdiction of ASTM Committee D19 on Water and is
the direct responsibility of Subcommittee D19.05 on Inorganic Constituents in (1) those that contain an analyte and (2) those that do not
Water.
contain and analyte above or below a specified action level.
Current edition approved May 1, 2018. Published May 2018. Originally
3.2.8 semi-quantitative method Type 1, n—a method whose
approved in 2003. Last previous edition approved in 2013 as D6850 – 13. DOI:
10.1520/D6850-18.
results are given in specified, discreet concentration ranges.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3.2.8.1 Discussion—Two types of examples of this method
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
would include semi-quantitative immunoassays or test strips.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. The cutoff concentration of the ranges has been predefined.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6850 − 18
3.2.9 semi-quantitative method Type 2, n—a method whose 6. Structure of a Quality Control System for Screening
results are reported as a single number along with the stated Methods
uncertainty.
6.1 General Considerations:
3.2.9.1 Discussion—The uncertainty will be reported as
6.1.1 Due to possible difficulties in performing several of
(standard deviation of x at a concentration of y). The values of
these requirements in the field it is acceptable to perform those
x and y can be established from the Initial Demonstration of
QC requirements in the laboratory.
Performance study.
6.1.2 The following are suggested at a minimum for ongo-
ing QC.
4. Significance and Use
6.1.2.1 Run a method blank containing no analyte, using
4.1 Screening methods are often used to determine the
reagent water as described in Specification D1193, with every
presence or absence of a specific analyte, groups of analytes,
batch to verify the test will produce a negative result.
classes of compounds or other indicators of chemical com-
6.1.2.2 Run a standard or set of standards with every batch.
pounds in order to determine if further analysis or action is
This may also serve as the calibration verification.
necessary. The determination whether to proceed with further
6.1.2.3 Run a sample duplicate with every batch. Ensure
action is useful in reducing the number of negative results for
that the replicate results meet the methods performance crite-
which the screening method serves as a surrogate.
ria.
4.2 The use of screening methods, whether to generate
6.1.3 It is required that the analyst using the screening
qualitative or semi-quantitative results, is increasingly becom-
method proves their proficiency with the test. The task group
ingausefultoolforregulatorymonitoring,processcontrol,and
responsible for the method will establish proficiency require-
site characterization. The appropriate use of a screening
ments.
method, or any other method for that matter, is dependent upon
6.1.4 When performing matrix evaluations it is recom-
the data quality objectives (DQOs) that are defined by the user
mended to use the actual matrix if possible. If not, a similar
of the data.
matrix should be used. Example: Use substitute wastewater, as
described in Practice D5905, for a wastewater matrix.This will
4.3 Persons responsible for assessing the quality of the data
determinethesuitabilityo
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D6850 − 13 D6850 − 18
Standard Guide for
QC of Screening Methods in Water
This standard is issued under the fixed designation D6850; 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*
1.1 This guide covers general considerations for the Quality Control quality control (QC) practices for use with screening
methods for organic and inorganic constituents in water. Methods are provided by various standard setting bodies, governmental
agencies, as well as many domestic and international manufacturers.
1.2 This guide provides general QC procedures that are applicable to a broad range of screening methodologies. These
procedures help to ensure the quality of data that is generated. Additional, method-specific or project specific requirements may
be necessary. This guide also includes general considerations regarding proper utilization of screening methods.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
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.
2. Referenced Documents
2.1 ASTM Standards:
D1129 Terminology Relating to Water
D1193 Specification for Reagent Water
D4840 Guide for Sample Chain-of-Custody Procedures
D5172 Guide for Documenting the Standard Operating Procedures Used for the Analysis of Water
D5847 Practice for Writing Quality Control Specifications for Standard Test Methods for Water Analysis
D5905 Practice for the Preparation of Substitute Wastewater
3. Terminology
3.1 Definitions—Definitions: For definitions of terms used in this guide, refer to Terminology D1129 and Practice D5847.
3.1.1 For definitions of terms used in this standard, refer to Terminology D1129 and Practice D5847.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 action level, n—a concentration of the analyte of concern at which some further action is required or suggested.
3.2.2 batch, n—a set (group) of samples analyzed along with QC samples; the quality of the sample-set’s results is indicated
by the results from the QC samples.
3.2.2.1 Discussion—
The number of samples in the batch is defined by the task group responsible for the method. See Practice D5847 for definition and
discussion of batch and batch size.
3.2.3 false negative, n—a negative response for a sample that contains the target analyte(s) at or above the stated action level.
This guide is under the jurisdiction of ASTM Committee D19 on Water and is the direct responsibility of Subcommittee D19.05 on Inorganic Constituents in Water.
Current edition approved Aug. 1, 2013May 1, 2018. Published August 2013May 2018. Originally approved in 2003. Last previous edition approved in 20082013 as
D6850 – 03 (2008).D6850 – 13. DOI: 10.1520/D6850-13.10.1520/D6850-18.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6850 − 18
3.2.4 false positive, n—a positive response for a sample that contains the target analyte(s) below the stated action level.
3.2.5 qualitative method, n—a validated method that detects presence or absence of an analyte at a specified screening limit.
3.2.6 screening limit, n—the concentration of analyte that can be determined with a given certainty.
3.2.6.1 Discussion—
The task group responsible for the method establishes the value of the screening limit.
3.2.7 screening method, n—a method that is used to separate or categorize samples.
3.2.7.1 Discussion—
An example would be a method that provides results that would be used to separate samples into: (1) those that contain an analyte
and (2) those that do not contain and analyte above or below a specified action level.
3.2.8 semi-quantitative method Type 1, n—a method whose results are given in specified, discreet concentration ranges.
3.2.8.1 Discussion—
Two types of examples of this method would include semi-quantitative immunoassays or test strips. The cutoff concentration of
the ranges has been predefined.
3.2.9 semi-quantitative method Type 2, n—a method whose results are reported as a single number along with the stated
uncertainty.
3.2.9.1 Discussion—
The uncertainty will be reported as (standard deviation of x at a concentration of y). The values of x and y can be established from
the Initial Demonstration of Performance study.
4. Significance and Use
4.1 Screening methods are often used to determine the presence or absence of a specific analyte, groups of analytes, classes of
compounds or other indicators of chemical compounds in order to determine if further analysis or action is necessary. The
determination whether to proceed with further action is useful in reducing the number of negative results for which the screening
method serves as a surrogate.
4.2 The use of screening methods, whether to generate qualitative or semi-quantitative results, is increasingly becoming a useful
tool for regulatory monitoring, process control, and site characterization. The appropriate use of a screening method, or any other
method for that matter, is dependent upon the Data Quality Objectivesdata quality objectives (DQOs) that are defined by the user
of the data.
4.3 Persons responsible for assessing the quality of the data generated by the use of screening methods should have detailed
Quality Control QC guidelines by which to assess data quality.
5. Consideration for Selection of an Appropriate Screening Method
5.1 The screening method chosen must be appropriate for the Action Level of the project.
5.2 The chosen screening method must allow for the necessary number of samples to be run in a timely manner, not to exceed
the storage limits of the sample as defined by the method.
5.3 Many screening methods will give a positive result for several compounds or class of compounds. It must be determined
if a more specific method is necessary to eliminate these positive results.
5.4 It is essential that an appropriate documentation system be established. A Standard Operating Procedurestandard operating
procedure (SOP) for the screening method containing the appropriate QC elements from this guide must be available. See Guides
D4840 and D5172 for information on establishing a SOP for a method.
5.5 Issues relating to timeliness of sample collection and analysis should be considered when selecting an appropriate screening
...