Quality Assurance and Control - UNECE

Data collection and infrastructure

Quality Assurance and Control

Quality Assurance and Control

Monitoring programs may not initially have been designed to cover all aspects of the WFD however it is desirable

they should be capable of providing data which is robust enough to meet the relevant national / international criteria

One out ¨C All out approach to quality

WFD Ecological and Chemical status

are assessed independently

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(WG%202.7).pdf

Print ISBN:9780470518366

Online ISBN:9780470716090

Quality Assurance and Control

Quality Assurance (QA) is all the planned and systematic activities implemented within the

Quality System (QS) that can be demonstrated to provide confidence that a product or service

meets the requirements for quality.

Quality Control (QC) describes the operational techniques and activities used to fulfil the

requirements for quality.

Quality Assurance is process orientated and focuses on defect prevention, while quality control

is product orientated and focuses on defect identification.

A Quality Assurance Plan (QAP) should be a central feature of any QA system

? It is prepared either as part of, or after, the monitoring programme planning process.

? Once the data quality objectives have been defined, the next important part of creating a QAP is

to define the roles and responsibilities of team members.

? In all cases the QAP should be completed and approved by all stakeholders before monitoring is

started and should be approved by all stakeholders.

? These two US EPA documents provide useful guidance for developing QAPs:





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Quality Assurance ¨C Field operations

? The sampling equipment required and sample collection methods should ideally be set

out in Standard Operating Procedures (SOPs)

? These should describe in sufficient detail the approach to:

? Preparation and decontamination of sampling equipment,

? Selection and preparation of sample containers, volumes to be sampled,

and any preservation reagents required

? Sample collection methods

? Sample preservation methods (as required).

? Field data equipment and calibration procedures e.g. for Temp, DO, pH, EC

? Standard references (used in the creation of the SOPs)

? Sample storage and transit procedures

? The individuals responsible for any corrective action should also be identified.



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Quality Assurance ¨C Field operations

Sources of sample contamination in the field can include:

? Contaminated sampling equipment. Carryover of substances from one sample

collection to the next may be caused by inadequate rinsing or cleaning of the

sampling and field preparation equipment between samples, e.g. buckets,

samplers, field filtration equipment, etc.

? The use of unsuitable sampling devices and containers (e.g. devices/containers that

may introduce contaminants to the samples through leaching or abrasion of the

container material, or from lubricants in pumps).

? Contamination from the general environment including:

? import of contaminants during sampling procedure, e.g. soil contact from bank

material and sediment, from abrasion of bridge railings,

? filling and storing of samples in air contaminated by pollutants, e.g. from exhaust

fumes

? outgassing of preservatives, or volatilisation from strongly contaminated samples.

? Cross contamination from preservative chemicals.

? Mixing up the sample bottle lids.

? Inappropriate storage and transport arrangements.

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