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Cyanotoxins in Inland Lakes of the United States: Occurrence and Potential Recreational Health Risks in the EPA National Lakes Assessment 2007
Loftin, K., J. Graham, E Hilborn, S. Lehmann, M. Meyer, J. Dietze, AND C. Griffith. Cyanotoxins in Inland Lakes of the United States: Occurrence and Potential Recreational Health Risks in the EPA National Lakes Assessment 2007. Harmful Algae. Elsevier B.V., Amsterdam, Netherlands, 56:77-90, (2016).
Water samples analyzed during the 2007 National Lake Survey indicated that although chlorophyll and cyanobacteria were common, cyanotoxins were detected less frequently. The current WHO indicators for the presence of microcystins, concurred with the presence of microcystins only 27% of the time among samples. More work is needed to develop sensitive and specific indicators of cyanotoxin risk among US surface waters. This work investigates the occurrence of a high priority CCL contaminant- cylindrospermopsin.
A large nation-wide survey or cyanotoxlns (1161 lakes)in the United States (U.S.) was conducted dunng the EPA National Lakes Assessment 2007. Cyanotoxin data were compared with cyanobacteria abundance- and chlorophyll-based World Health Organization (WHO) thresholds and mouse toxicity data to evaluate potential recreational risks. Cylindrospermopsins, mlcrocystins,and saxitoxins were detected (ELISA) In 4.0, 32, and 7.7% or samples with mean concentrations of 0.56, 3.0, and 0.061 mg/L, respectively (detections only). Co-occurrence of the three cyanotoxln classes was rare (0.32%) when at least one toxin was detected. Cyanobacterta were present and dominant In 98 and 76% or samples, respectively. Potential anatoxin-, cylndrospermopsin-, microcystin-, and saxitoxin-·producing cyanobacteria occurred in 81, 67, 95, and79% of samples, respectively. Anatoxin-a and nodularin-R were detected (LC/MS/MS) In 15 and 3.7% samples (n = 27). The W HO moderate and high risk thresholds for microcystlns, cyanobacteria abundance, and total chlorophyll were exceeded In 1.1, 27, and 44% or samples, respectively. Complete agreement by all three WHO microcystln metrics occurred In 27% of samples. This suggests that WHO microcystln metrics based on total chlorophyll and cyanobactenal abundance can overestimate microcystln risk when compared to WHO mlcrocystin thresholds. The lack of parity among the WHO thresholds was expected since chlorophyll ls common amongst all phytoplankton and not all cyanobacteria produce mlcrocystms.