The purpose of the program was to determine what standards are currently available, their suitability for validating present in-situ water quality measurements, and to assess the accuracy of measurement traceability from the in-situ instrument to a recognized standard. The ease with which in-situ systems gather large volumes of data pertinent to environmental studies, pollution monitoring, and other applications is such that their continued use and growth is assured. Because their use is recent, inattention to establishing standards has made suspect the absolute accuracy of the data and thus, the comparability between data sets. Most users have devised their own techniques of assuring the relative accuracy of their in-situ data, but no recognized standard techniques exist. It was found that deficiencies exist in two areas: (1) lack of an adequate (multiple point) primary standard for some parameters (e.g., salinity and dissolved oxygen); and (2) failure by in-situ system users to follow standard methods (where they exist) for calibration and standardization. The study recommends the establishment of standard reference materials and methods for calibration and standardization to assure accuracy of parameters measured in-situ. It is further recommended in the study that development of specific means to achieve the traceability to standards be initiated.

"April 1979." "Interagency Agreement No. D5-E693." "Program No. EPA-78-BEA." "Program Element No. 1 NE 625C." "NOAA--S/T 79-387"--Page 4 of cover "This study was conducted as part of the Federal Interagency Energy/Environment Research and Development Program by Interstate Electronics Corporation, Ocean Engineering Division, Anaheim, California." Includes bibliographical references (pages 35-36).