title: In vivo phycocyanin flourometry as a potential rapid screening tool for predicting elevated microcystin concentrations at eutrophic lakes.
abstract: Current approaches for assessing human health risks associated with cyanotoxins often rely on the quantification of microcystin. Significant limitations of current approaches are cost and time to obtain a result. To address these challenges, a numerical index for screening microcystin risks above the World Health Organization's (WHO) low-risk threshold for microcystin was developed for eutrophic Midwestern U.S. lakes based on water quality results from 182 beach water samples collected from seven Ohio lakes. In 48 (26.4%) samples we observed microcystin concentrations as measured by ELISA that exceeded the 4 μg/L microcystin threshold. A multivariable logistic regression model using practical real-time measures of in vivo phycocyanin (by fluorometry) and secchi depth was constructed to estimate the probability of a beach sample exceeding 4 μg/L microcystin. The final model achieved statistical significance (p = 0.030) as well as good calibration (as measured by the goodness-of-fit test comparing observed to expected counts within deciles of risk based on the model, p = 0.329) and discrimination (as indicated by the area under the receiver-operator-curve (0.795)). These results demonstrate two rapid and practical measures of recreational water quality are effective in identifying "at risk" lake conditions warranting additional management (e.g., advisory and/or advanced testing).
authors.affiliation: College of Public Health, Division of Environmental Health Sciences, The Ohio State University, 1841 Neil Avenue, Columbus, Ohio 43210-1351, United States.
authors.forename: Jason W
authors.initials: JW
authors.lastname: Marion
authors.forename: Jiyoung
authors.initials: J
authors.lastname: Lee
authors.forename: J R
authors.initials: JR
authors.lastname: Wilkins
authors.forename: Stanley
authors.initials: S
authors.lastname: Lemeshow
authors.forename: Cheonghoon
authors.initials: C
authors.lastname: Lee
authors.forename: Evan J
authors.initials: EJ
authors.lastname: Waletzko
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Buckley
mesh_terms: D001493:Bathing Beaches; D002734:Chlorophyll / Q000032:analysis; D000077194:Chlorophyll A; D004269:DNA, Bacterial / Q000235:genetics; D004784:Environmental Monitoring / Q000379:methods*; D005068:Eutrophication; D005470:Fluorometry; D005618:Fresh Water / Q000032:analysis; D016015:Logistic Models; D008387:Marine Toxins; D052998:Microcystins / Q000032:analysis*; D046931:Microcystis / Q000235:genetics / Q000302:isolation & purification; D009820:Ohio; D010798:Phycocyanin / Q000032:analysis*; D060888:Real-Time Polymerase Chain Reaction; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D004269:DNA, Bacterial; D008387:Marine Toxins; D052998:Microcystins; D014874:Water Pollutants, Chemical; D010798:Phycocyanin; D002734:Chlorophyll; C057862:cyanoginosin LR; D000077194:Chlorophyll A