Evaluation of Chemical Data From Selected Sites in the Surface-Water Ambient Monitoring Program (SWAMP) in Florida
GEOLOGICAL SURVEY TALLAHASSEE FL WATER RESOURCES DIV
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A cooperative study between the Florida Department of Environmental Protection FDEP and the U.S. Geological Survey was conducted to assess the integrity of selected water-quality data collected at 150 sites in the FDEP Surface-Water Ambient Monitoring Program SWAMP in Florida. The assessment included determining the consistency of the water-quality data collected statewide, including commonality of monitoring procedures and analyses, screening of the gross validity of a chemical analysis, and quality assurance and quality control QAQC procedures. Four tests were used to screen data at selected SWAMP sites to estimate the gross validity of selected chemical data 1 the ratio of dissolved solids in milligrams per liter to specific conductance in microsiemens per centimeter 2 the ratio of total cations in milliequivalents per liter multiplied by 100 to specific conductance in microsiemens per centimeter 3 the ratio of total anions in milliequivalents per liter multiplied by 100 to specific conductance in microsiemens per centimeter and 4 the ionic charge-balance error. Although the results of the four screening tests indicate that the chemical data generally are quite reliable, the extremely small number of samples less than 5 percent of the total number of samples with sufficient chemical information to run the tests may not provide a representative indication of the analytical accuracy of all laboratories in the program. In addition to the four screening tests, unusually low or high values were flagged for field and laboratory pH less than 4.0 and greater than 9.0 and specific conductance less than 10 and greater than 10,000 microsiemens per centimeter. The numbers of flagged data were less than 1 per- cent of the 19,937 water samples with pH values and less than 0.6 percent of the 16,553 water samples with specific conductance values.
- Hydrology, Limnology and Potamology