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QA/QC FOR ENVIRONMENTAL MEASUREMENT
Unit 4: Module 13, Lecture 1
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s2
What is quality assurance (QA)?
a broad plan for maintaining quality in all aspects of a program
- Keith et al. (1983)
establishes the need for quality control (QC)
http:/water.usgs.gov/
QA/QC for environmental measurement
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s3
Quality control refers to routine technical activities – the purpose of which is to control error
QC can be considered the “HOW” of the QA process
applicable to field, lab and office procedures
http://oceanexplorer.noaa.gov/explorations/02hudson/logs/aug29/aug29.html
http://www.jmg.gov.my/Client_s_Charter/client_s_charter.html
QA/QC for environmental measurement
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s4
QA for environmental measurement
Why do we need quality assurance for environmental measurement? understand data reliability quantify areas of analytical uncertainty standardize measurement to allow for repeatable
and comparable data across time and place
QA ensures that data will meet defined standards of quality with a standard level of confidence
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s5
QA for environmental assessment
Need for consistency - monitoring a copper impacted stream
Is this problem getting worse or is being mitigated?
How can you tell? Why is standardized
measurement so important?
http://www.darcnw.noaa.gov/bbpix.htm
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s6
Who in the environmental arena uses quality assurance measures and when is it necessary?
nearly all REGULATORY decisions about: issuing permits, monitoring human health and environmental quality, pollution investigations and the progress of site remediation are based on one thing -- the data gathered from the site.
Where is QA applicable?
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s7
What other environmental arenas utilize quality assurance measures? laboratories universities and
research organization
Where is QA applicable?
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s8
Non-research areas utilize environmental QA measures also business and industry lobbying groups and special interests legislators lawyers others
http://www.lanl.gov/orgs/pa/News/060297.html
http://gov.state.nv.us/SpecialSession072902.asp
Where is QA applicable?
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s9
Quality assurance vs. quality control
Quality Assurance (QA) broad program plan establishes the need
for QC
Quality Controls (QC) individual checks
and balances the “HOW” of QA
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s10
Where is QC applicable?
Quality control is applicable in all aspects of a project including:
Field data collection and sampling
Laboratory analysis and processing
Data evaluation and assessment
Reporting and project documentation
QC provides steps that ensure data will meet defined standards of quality with a standard level of confidence
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s11
QC in the field
QC is particularly critical in filed data collection often the most costly aspect of a project data is never reproducible under the exact same
condition or setting
http://www.fe.doe.gov/techline/tl_hydrates_oregon.shtml
http://climchange.cr.usgs.gov/info/lacs/watersampling.htm
sechi readings field filtration logging sea cores
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s12
QC in the field
Standardized field method programs US Army Corps of
Engineers ASTM methods USGS classification APHA AIHA NIST
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s13
QC in the laboratory
Laboratory data analysis, measurement and acquisition: Chain of custody forms Equipment calibration Storage practices Analytical methods Holding times MDLs
www.odc.gov/noeh/dls
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s14
QC in the laboratory
Standardized laboratory method programs EPA Methods State Modified
Methods APHA Methods ASTM AIHA
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s15
QC in the office
In office planning, data evaluation and summation of results: QAPP – quality assurance
project plan outlines all project management assessment and oversight data validation
www.cr.nps.gov/aad/collections/ mgt_pr.htm
http://www.va.gov/optometry/page.cfm?pg=4Photo from MN DNR
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s16
QC for environmental measurement
Why do we need quality control? To prevent errors from happening To identify and correct errors that have taken
place
QC is used to PREVENT and CORRECT ERRORS
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s17
QC: Internal vs. external measures
Internal quality control “controllable” by those responsible for
undertaking the project or directly “involved in the program”
External quality control a “set of measures” established for and
conducted by those people and organizations “outside of the program”
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s18
Quality control (QC): Internal
Internal Quality Control: Equipment calibration Proper training and
certification of participants Proper sampling and
containment techniques Proper data documentation
http://www.ars.usda.gov/is/np/fnrb/fnrb1001.htm
http://il.water.usgs.gov/adcp/photos/class_apr99.html
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s19
Quality control (QC): External
External quality control: Performance audits Split sample analysis Replicate (duplicate)
sample analysis
http://www.ars.usda.gov/is/np/fnrb/fnrb1001.htm
http://www.tfhrc.gov/pubrds/novdec98/seven.htm
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s20
Quality Assurance Project Plans (QAPP)
A quality assurance project plan (QAPP) is a project-specific QA document.
The QAPP outlines the QC measures used in implementing the project.
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s21
Quality Assurance Project Plans (QAPP)
The QAPP governs work conducted in the field, laboratory, and the office.
The QAPP: guides the selection of project parameters and
procedures guides data management and analysis provides steps to determine the validity of
specific sampling or analysis procedures designates both internal and external QC
measures
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s22
QA/QC: Data objective and key concepts
Successful data collection and analysis is dependant upon “The PARCC Parameters”: Precision Accuracy Representativeness Completeness Comparability
The key concepts of QA/QC are the “PARCC” Parameters – the WHY of the QAPP
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s23
Key concepts of QA/QC:
Precision - degree of agreement there is
between repeated measurements of the same characteristic
can be biased – meaning there is a consistent error in the results
Accuracy - measures how close data results
are to a true or expected value – does not allow for bias
http://www.d.umn.edu/faculty/ UMD med school
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s24
accuracy = (average value) – (true value) precision represents
repeatability bias represents
amount of error
low bias and high precision = statistical accuracy
Key concepts of QA/QC: Accuracy
http://www.epa.gov/owow/monitoring/volunteer/qappexec.html
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s25
Key concept QA/QC: Representativeness
Representativeness - extent to which measurements actually represent
the true environmental condition or population at the time a sample was collected.
Representative data should result in repeatable data
Does this
represent this??
http://pubs.usgs.gov/fs/fs-0058-99
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s26
Key concepts of QA/QC: Completeness
Completeness - comparison between the amount of data
intended to be collected vs. actual amount of valid (usable) data collected.
In the design of the QAPP – will the goals of the plan meet assessment needs? Will sufficient data be collected?
Would this give usable data ??
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s27
Key concepts of QA/QC: Comparability
Comparability - the extent to which data can be compared
between sample locations or periods of time within a project, or between projects
Will similar data from these sites be
Comparable ??
http://www.nssl.noaa.gov/publicaffairs/backgrounders/backgrounder_ww.html
http://www.nrcs.usda.gov/programs/cta/ctasummary.html
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s28
Review: QA vs. QC
Quality Assurance (QA) broad program plan establishes the need
for QC
Quality Controls (QC) standardized tests
and methods the “HOW” of QA
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s29
Review: Quality Assurance Project Plans
The QAPP is a project-specific QA document.
The QAPP outlines the QC measures to be taken for the project.
QAPP guides: the selection of
parameters and procedures
data management and analysis
steps taken to determine the validity of specific sampling or analysis procedures
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s30
Elements of a QAPP
The QAPP governs work conducted in the field, laboratory, and the office.
QAPP can be broken out into four areas of the project Project management (office) Measurement and data acquisition (field and lab) Assessment and oversight (field, lab, and office) Data validation and usability (field, lab, and
office)
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s31
Review: QA/QC key concepts
“The PARCC Parameters” are the WHY of QA/QC and assure successful data analysis: Precision Accuracy Representativeness Completeness Comparability
The key concepts and WHY of QA/QC are the “PARCC” Parameters
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s32
References
EPA 1996, Environmental Protection Agency Volunteer Monitor’s Guide to: Quality Assurance Project Plans. 1996. EPA 841-B-96-003, Sep 1996, U.S. EPA, Office of Wetlands, Washington, D.C. 20460, USA http://www.epa.gov/owowwtr1/monitoring/volunteer/qappexec.htm
Developed by: Zwiebel, Filbin Updated: June 14, 2005 U5-m13a-s33
•http://waterontheweb.org/index.html