Schedule B3 - COAG Standing Council on Environment and Water

4 Quality assurance
4.1 Definitions
The terms ’quality assurance‘ and ’quality control‘ are often misinterpreted. This guideline
defines them as follows (ISO 8402–1994):
Quality assurance (QA) is ’all the planned and systematic activities implemented within the quality
system and demonstrated as needed to provide adequate confidence that an entity will fulfil requirements
for quality’.
This encompasses all actions, procedures, checks and decisions undertaken to ensure the
accuracy and reliability of analysis results. It includes routine procedures to ensure proper
sample control, data transfer, instrument calibration, the decisions required to select and
properly train staff, select equipment and analytical methods, and the day-to-day judgements
resulting from regular scrutiny and maintenance of the laboratory system.
Quality control (QC) is ‘the operational techniques and activities that are used to fulfil the requirements
for quality’.
These are the QA components that serve to monitor and measure the effectiveness of other QA
procedures by comparing them with previously decided objectives. They include measurement
of reagent quality, apparatus cleanliness, accuracy and precision of methods and
instrumentation, and reliability of all of these factors as implemented in a given laboratory from
day to day.
A complete discussion of either of these terms or the steps for implementing them is beyond the
scope of this guideline; suffice to say, sound laboratory QA and QC procedures are essential. In
brief, laboratories should incorporate quality laboratory management systems, and participate
in accreditation and/or self-audit systems, to ensure reliable results are produced by trained
analysts, using validated methods and suitably calibrated equipment, and to maintain proper
sample management and recordkeeping systems. For more information on good laboratory
practice and QA procedures, refer to guidance from NATA (Cook 2002, NATA Technical note
23, NATA 2007) and Standards Australia (AS 2830.1-1985).
4.2 Recommended minimum QC procedures
The laboratory should adopt, at a minimum, the minimum QC concepts and procedures
described below and be able to demonstrate:
• method proficiency within the laboratory
• conformance to the performance characteristics expected of the method
• confidence in the results produced.
Recommended QC procedures for all soil analyses are described in US EPA SW-846 (in that
document, see Chapter 1: ‘Quality control’)
4.2.1 Process batch
For the purposes of QC requirements, a process batch is deemed to consist of up to 20 samples
which are similar in terms of sampling and testing procedures and are processed as a unit for
QC purposes. If more than 20 samples are being processed, this should be considered as more
than one batch.
<strong>Schedule</strong> <strong>B3</strong> - Guideline on laboratory analysis of potentially contaminated soils 7