WATER QUALITY--Requirements for WRD approval of water quality analytical methods March 19, 1979 QUALITY OF WATER BRANCH TECHNICAL MEMORANDUM NO. 79.11 Subject: WATER QUALITY--Requirements for WRD approval of water quality analytical methods One of the responsibilities of the Quality of Water Branch is to evaluate proposed new analytical methods with respect to acceptability for operational use within WRD for the collection of water quality data. In the past, two categories of approval have been recognized. These were (l) full approval, and (2) provisional approval. Fully approved methods were those that had been shown through long-term use and/or extensive testing to result in data of acceptable accuracy for WRD work. These methods have been published in the Techniques of Water-Resources Investigations of the United States Geological Survey (TWRI) series. Provisional methods usually were new methods that had not yet been fully tested and therefore had not been published in the TWRI series. Documentation for provisional methods was distributed to WRD field offices by Quality of Water Branch Technical Memoranda. Until now analytical methods have been evaluated for acceptance as either approved or provisional methods largely on an individual basis, without consistent guidelines. However, with the increased emphasis the Division is placing on methods documentation, quality assurance, and the need to insure comparability of methods among agencies, it is clear that a more formal methods approval procedure must now be established. The purpose of this memo is to define the procedures that will be followed in the future to obtain formal approval of new water quality analytical methods for use in the collection of data for the Water Resources Division. To accomplish this end, two categories of approved analytical methods are formally established. These are: (l) official methods, and (2) provisional methods. A description of each of these categories and requirements for their approval are given below: Official Methods--Methods in this category are considered to be the official methods of the Water Resources Division and have full approval for use in the collection of water resources data. They are or will be published in the TWRI series. Data collected by these methods may be stored in WATSTORE and published in the annual basic data reports of the Water Resources Division. Requirements for approval are: 1. Submission of documentation of the proposed method in TWRI format to the Chief, Quality of Water Branch. 2. Submission to and approval by the Quality of Water Branch of a method-development report giving information and supporting data on the following: (a) applicable range, detection limit, and sensitivity of the method (b) known and possible interferences (c) precision and bias of the method. These data should as a minimum include: (l) single-laboratory and multiple operator tests which would include at least 10 replicate analyses each of pure solutions, natural waters, and spiked natural waters at three concentrations covering the range of the method. (2) a sufficient block of data to permit a statistical comparison to be made between results obtained by using the proposed method and results from currently used methods (if such methods exist) for a wide variety of water types covering the applicable range of the method. (d) comparative data on production rates, when possible. 3. Submission of statements describing hazardous chemical reactions and/or reagents that are involved in the method, sample preservation requirements, and level of skill and/or special training requirements needed by personnel using the method. 4. Submission of the results of technical reviews of the method documentation and methods-development report by at least two colleagues, one of which must be outside the method author's headquarters area. In addition to the above minimum requirements for approval, if it is determined that the proposed method will be widely used in the WRD by more than one laboratory, the Quality of Water Branch will initiate plans to obtain more extensive data on precision and bias, including multi-laboratory multiple-operator data. However, approval of the method would not be dependent on obtaining this additional data. Provisional Methods--Methods in this category are believed to result in data comparable to those obtainable from official methods but are likely to be used by the WRD to such a limited extent that they have not received extensive in-house testing by WRD personnel. Many of the methods published in such reliable compendia as Standard Methods, EPA Methods for Chemical Analysis of Water and Wastes, and the ASTM Book of Standards, and which are used by in-house, cooperator, or contractor laboratories in support of WRD programs, would be accepted for approval in this category. These methods will not be published in the TWRI series. Data collected by these methods may be stored in WATSTORE if a parameter code exists, and the data may be published in the annual basic data reports. Requirements for acceptance of methods in this category are as follows: 1. Submission of a copy of the method to the Chief, Quality of Water Branch, with an explanation of why approval of the method is desired. 2. Provision of the same type of information on precision and bias as required for Official Method approval; however, in this case, data obtained by other than WRD personnel will be acceptable for consideration. Special Methods--In contrast to the two categories of approved analytical methods, there are some methods that have specialized or limited application and therefore need not be submitted to the Chief, Quality of Water Branch, for approval. These include methods used in support of research, experimental or developmental methods used by a central laboratory, and screening methods used in the field or in the laboratory. Data collected by these methods are not to be stored in WATSTORE or published in the annual basic data reports. However, the data may be published in interpretive reports or project data reports provided the method is fully described or an appropriate reference is cited to provide a basis for peer evaluation of analytical results. Defense of the validity of such a method is therefore the responsibility of the hydrologist using the method. Requests for approval of water quality analytical methods should be submitted to the Chief, Quality of Water Branch, with copies to the appropriate Regional Hydrologist. The requests should be accompanied by supporting documents appropriate to the category of approval that is requested, including copies of reviewers' comments. The Quality of Water Branch will maintain a listing of all approved methods and periodically will distribute to the field a list of all approved methods which have not been published in the TWRI series. Your continued cooperation in maintaining high standards for the quality of data collected by the Water Resources Division will be appreciated. R. J. Pickering Chief, Quality of Water Branch WRD Distribution: A,B,S,FO,PO