Environmental Engineering Reference
In-Depth Information
Sampling plan/design
(Chapter 3)
Sampling techniques
(Chapter 4)
Methodology
(Chapter 5)
Sample preparation
(Chapter 7)
QA/QC
(Chapter 5)
Sampling analysis
(Chapter 6,8,9,10,11,12)
Data analysis
(Chapter 2)
Figure 1.1.
Environmental data acquisition process
Unfortunately, there is a general misconception among many environmental
professionals that the quality of data pertaining to a contaminated site is primarily
determined by the nature of analytical methods used to acquire data. This
assumption, which underestimates the importance of sampling uncertainties, can
lead to a pronounced, negative impact on the cost-effective remediation of a
contaminated site. In fact, it is of little use by placing an emphasis only on analytical
uncertainty when sampling uncertainty is large and not addressed (Crumbling
et al., 2001).
Errors in environmental data acquisition can be minimized through the proper
design and implementation of a quality program. Two main parts of a quality
program are quality control (QC) and quality assurance (QA). QC is generally a
system of technical activities aimed at controlling the quality of data so that it
meets the need of data users. QC procedures should be specified to measure the
precisions and bias of the data. A QA program is a management system that ensures
the QC is working as intended. QA/QC programs are implemented not only to
minimize errors from both sampling and analysis, but many are designed to quantify
the errors in the measurement. Details on QA/QC will be presented in Chapter 5.
1.2 ENVIRONMENTAL SAMPLING
1.2.1 Scope of Environmental Sampling
The scope of environmental sampling can be illustrated by a sample's life with the
following seven consecutive steps (Popek, 2003). Since these steps are irreversible, a
mistake can be detrimental. These seven steps of a sample's life are as follows: (1) a
sample is planned (''conceived''); (2) a sampling point is identified; (3) the sample is
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