Methodology and Quality Assurance/Quality Control of Environmental Analysis - Fundamentals of Environmental Sampling and Analysis - page 98

the sources of these methods, and to familiarize oneself with the structures of these
various resources.
5.1 OVERVIEW ON STANDARD METHODOLOGIES
A method is a body of procedures and techniques for performing an activity
(e.g., sampling, chemical analysis, quantification), systematically presented, in
the order in which they are to be executed. Before the introduction to various
standard methods, the reader must be aware of the clear difference between
regulatory methods and consensus methods. The regulatory methods are approved
by the U.S. EPA and are mandatory under a certain program or a law. The consensus
methods are published by professional organizations such as the American Society
for Testing Materials (ASTM), the U.S. Geological Survey (USGS), and the Asso-
ciation of Official Analytical Chemists (AOAC). In some cases, the differences are
not entirely clear because many of the consensus methods have been adopted by the
U.S. EPA. A standard U.S. EPA method typically has the following components:
Scope and application: overview and potential problems/variations
Summary of method: overview of analysis
Interferences: contamination of sample during handling
Safety: protection of analyst
Apparatus and materials: details of laboratory hardware
Reagents: details of chemicals, preparation of standards
Calibration: responses, calibration curves, and quantitation
Quality control: proof that laboratory can meet specifications of method
Sample collection, preservation, handling: details of sampling
Extraction procedure: details of method to extract organics from matrix
Instrumentation: type of instrumentation and operating procedures
Qualitative identification
Calculations: quantitative analysis
Method performance: MDLs
5.1.1 The U.S. EPA Methods for Air, Water,
Wastewater, and Hazardous Waste
Several offices within the U.S. EPA are responsible for generating or requiring the
use of specific sampling and analytical methods. These include the Office of Air
Quality Planning and Standards (OAQPS), the Office of Water (OW), and the Office
of Solid Waste (OSW). These offices published many test methods primarily in print
documents during the early years of the EPA. Starting in the mid-1990s, electronic
versions of EPA air methods began to appear, and some water methods were
distributed on floppy disks. In the late 1990s, EPA issued two compendium methods