qa/qc for environmental measurement

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


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


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


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


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?


What other environmental arenas utilize quality assurance measures? laboratories universities and

research organization



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



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


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


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


QC in the field

Standardized field method programs US Army Corps of

Engineers ASTM methods USGS classification APHA AIHA NIST


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


QC in the laboratory

Standardized laboratory method programs EPA Methods State Modified

Methods APHA Methods ASTM AIHA


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


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


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”


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


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


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.


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


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


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


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


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


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 ??


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


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


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


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)


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


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


•http://waterontheweb.org/index.html

qa/qc for environmental measurement

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