[The assigned parameter/method codes reflect a coding of the data based on information from technical memorandum QW88_05 and records of national network protocols (memoranda QW84_16 and QW85_19). If an observation was unavailable for the indicated parameter code (column 4), the alternate parameter codes were searched for an available value according to the specified dates and parameter order. In the CD-ROM data sets, these values were assigned their corresponding parameter and method codes in column 4]
__________________________________________________________________________________________________ Constituent Dates Method of determination Parameter & Alternate method code parameter codes ___________________________________________________________________________________________________ Data required by network protocols ___________________________________________________________________________________________________ Alkalinity Before Lab, fixed-endpoint titration1, 00417 A 00410, 00430, 00431, 10-01-84 unfiltered samples. 95430, 90410, 95410, 00421 Alkalinity 10-01-84 - Field, fixed-endpoint titration, 00410 A 00430, 00431 09-30-85 unfiltered samples. Alkalinity 10-01-85 - Field, fixed-endpoint titration, 39036 A 00410, 00430, 00431 09-30-95 filtered samples. Bicarbonate 10-01-85 - Field, incremental titration, 00453 B 99440, 00450 09-30-95 filtered samples. Carbonate 10-01-85 - Field, incremental titration, 00452 B 99445, 00447 09-30-95 filtered samples. ___________________________________________________________________________________________________ Optional national network data ___________________________________________________________________________________________________ Alkalinity Before Field, incremental titration, 00419 B 99430 10-01-85 unfiltered samples. Alkalinity 10-01-85 - Field, incremental titration, 39086 B 99430, 00419 09-30-95 filtered samples. Bicarbonate Before Field, fixed-endpoint titration, 00440 A 10-01-85 unfiltered samples. Bicarbonate 10-01-85 - Field, incremental titration, 00450 B 99440 09-30-95 unfiltered samples. Carbonate Before Field, fixed-endpoint titration, 00445 A 10-01-85 unfiltered samples. Carbonate 10-01-85 - Field, incremental titration, 00447 B 99445 09-30-95 unfiltered samples. ___________________________________________________________________________________________________ 1 A limited number of field personnel may have conducted field determinations of alkalinity by fixed-endpoint titration. These cases are coded as laboratory analyses.