caa a22 4500 467902151 CHVBK 20180406152821.0 cr unu---uuuuu 170328e20060501xx s 000 0 eng 10.1007/s10661-006-7571-z doi (NATIONALLICENCE)springer-10.1007/s10661-006-7571-z Comparison and Verification of Bacterial Water Quality Indicator Measurement Methods Using Ambient Coastal Water Samples [Elektronische Daten] [John Griffith, Larissa Aumand, Ioannice Lee, Charles Mcgee, Laila Othman, Kerry Ritter, Kathy Walker, Stephen Weisberg] More than 30 laboratories routinely monitor water along southern California's beaches for bacterial indicators of fecal contamination. Data from these efforts frequently are combined and compared even though three different methods (membrane filtration (MF), multiple tube fermentation (MTF), and chromogenic substrate (CS) methods) are used. To assess data comparability and quantify variability within method and across laboratories, 26 laboratories participated in an intercalibration exercise. Each laboratory processed three replicates from eight ambient water samples employing the method or methods they routinely use for water quality monitoring. Verification analyses also were conducted on a subset of wells from the CS analysis to confirm or exclude the presence of the target organism. Enterococci results were generally comparable across methods. Confirmation revealed a 9% false positive rate and a 4% false negative rate in the CS method for enterococci, though these errors were small in the context of within- and among-laboratory variability. Fecal coliforms also were comparable across all methods, though CS underestimated the other methods by about 10%, probably because it measures only E. coli, rather than the larger fecal coliform group measured by MF and MTF. CS overestimated total coliforms relative to the other methods by several fold and was found to have a 40% false positive rate in verification. Across-laboratory variability was small relative to within- and among-method variability, but only after data entry errors were corrected. One fifth of the laboratories committed data entry errors that were much larger than any method-related errors. These errors are particularly significant because these data were submitted in a test situation where laboratories were aware they would be under increased scrutiny. Under normal circumstances, it is unlikely that these errors would have been detected and managers would have been obliged to issue beach water quality warnings. Springer Science + Business Media, Inc., 2006 fecal indicator bacteria nationallicence laboratory intercalibration nationallicence method comparison nationallicence water quality nationallicence Griffith John Southern California Coastal Water Research Project (SCCWRP), 7171 Fenwick Lane, 92683, Westminster, CA, USA aut Aumand Larissa MEC Analytical Systems, Inc., Carlsbad, California, USA aut Lee Ioannice City of Los Angeles, Department of Sanitation, Los Angeles, California, USA aut Mcgee Charles Orange County Sanitation District, Fountain Valley, California, USA aut Othman Laila City of San Diego, Metropolitan Waste Water Department, San Diego, California, USA aut Ritter Kerry Southern California Coastal Water Research Project (SCCWRP), 7171 Fenwick Lane, 92683, Westminster, CA, USA aut Walker Kathy Los Angeles County Sanitation District, Whittier, California aut Weisberg Stephen Southern California Coastal Water Research Project (SCCWRP), 7171 Fenwick Lane, 92683, Westminster, CA, USA aut Environmental Monitoring and Assessment Kluwer Academic Publishers 116/1-3(2006-05-01), 335-344 0167-6369 116:1-3<335 2006 116 10661 https://doi.org/10.1007/s10661-006-7571-z text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10661-006-7571-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Griffith John Southern California Coastal Water Research Project (SCCWRP), 7171 Fenwick Lane, 92683, Westminster, CA, USA aut NATIONALLICENCE 700 1- Aumand Larissa MEC Analytical Systems, Inc., Carlsbad, California, USA aut NATIONALLICENCE 700 1- Lee Ioannice City of Los Angeles, Department of Sanitation, Los Angeles, California, USA aut NATIONALLICENCE 700 1- Mcgee Charles Orange County Sanitation District, Fountain Valley, California, USA aut NATIONALLICENCE 700 1- Othman Laila City of San Diego, Metropolitan Waste Water Department, San Diego, California, USA aut NATIONALLICENCE 700 1- Ritter Kerry Southern California Coastal Water Research Project (SCCWRP), 7171 Fenwick Lane, 92683, Westminster, CA, USA aut NATIONALLICENCE 700 1- Walker Kathy Los Angeles County Sanitation District, Whittier, California aut NATIONALLICENCE 700 1- Weisberg Stephen Southern California Coastal Water Research Project (SCCWRP), 7171 Fenwick Lane, 92683, Westminster, CA, USA aut NATIONALLICENCE 773 0- Environmental Monitoring and Assessment Kluwer Academic Publishers 116/1-3(2006-05-01), 335-344 0167-6369 116:1-3<335 2006 116 10661 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer