The procedures described in Standard Methods for the Examination of Water and Wastewater are intended for use in analyzing a wide range of waters, including surface water, ground water, saline water, domestic and industrial water supplies, cooling or circulating water, boiler water, boiler feed water, and treated and untreated municipal and industrial wastewaters. In recognition of the unity of the water, wastewater, and watershed management fields, the analytical methods are categorized based on constituent, not type of water.
An effort has been made to present methods that apply generally. When alternative methods are necessary for samples of different composition, the basis for selecting the most appropriate method is presented as clearly as possible. In specific instances (e.g., samples with extreme concentrations or otherwise unusual compositions or characteristics), analysts may have to modify a method for it to be suitable. If so, they should plainly state the nature of the modification when reporting the results.
Certain procedures are intended for use with sludges and sediments. Here again, the effort has been made to present methods with the widest possible application. However, these methods may require modification or be inappropriate for chemical sludges or slurries, or other samples with highly unusual composition.
Most of the methods included here have been endorsed by regulators. Regulators may not accept procedures that were modified without formal approval.
Methods for analyzing bulk water-treatment chemicals are not included. American Water Works Association committees prepare and issue standards for water treatment chemicals.
Laboratories that desire to produce analytical results of known quality (i.e., results are demonstrated to be accurate within a specified degree of uncertainty) should use established quality control (QC) procedures consistently. Part 1000 provides a detailed overview of QC procedures used in the individual standard methods as prescribed throughout Standard Methods. Part 1000 also addresses laboratory safety, sampling procedures, and method development and validation. Material presented in Part 1000 is not necessarily intended to be prescriptive nor to replace or supersede specific QC requirements given in individual sections of this book. Parts 2000 through 9000 contain sections describing QC practices specific to the methods in the respective parts; these practices are considered to be integral to the methods. Most individual methods contain explicit instructions to be followed for that method (either in general or for certain regulatory applications).
Similarly, the overview of topics covered in Part 1000 is not intended to replace or be the sole basis for technical education and training of analysts. Rather, the discussions are intended as aids to augment and facilitate reliable use of the test procedures herein. Each section in Part 1000 contains references that can be reviewed to gain more depth or details for topics of interest.