1. Preliminary Assessment of Cyanotoxin Occurrence in Lakes and Reservoirs in the
United States
Keith A. Loftin, Jennifer L. Graham, Michael T. Meyer, Andrew C. Ziegler, Julie E. Dietze
U.S. Geological Survey
Susan Holdsworth, Ellen Tarquinio
U.S. Environmental Protection Agency

2. Acknowledgements USEPA USGS Office of Wetlands, Oceans and Watersheds
(National Lake Assessment Website:
USGS
Toxic Substance Hydrology Program (
Disclaimer:
Any use of trade, product, or firm names in this presentation is for descriptive
purposes only and does not imply endorsement by the U.S. Government.
Our research group.

3. Outline Concerns and Guidelines
Introduction to Cyanotoxins and Cyanobacteria
USGS cyanotoxin sampling protocol:
C. Previous Occurrence in Midwest
D. Toxin Studies
EPA National Lake Assessment (2007 US EPA NLA)
USGS Midwestern US Cyanotoxin Reconnaissance of
Cyanobacterial Blooms (2006 USGS MCR)
E. Take Home Message
Lakeline, 26(2), Summer 2006.

4. Concerns and Guidelines
Binder Lake, IA August 2006
Known Acute effects and chronic effects
- hepatotoxins
- neurotoxins
- dermatotoxins
- carcinogens
EPA Contaminant Candidate List 3
Anatoxin-a
Cylindrospermopsin
Microcystin-LR
WHO guidelines – Microcystin-LR
Drinking water – 1.0 ppb
Recreational water
Low Risk - < 10 ppb
Moderate Risk ppb
High Risk - > 20 ppb

5. Cyanobacteria Made the News in at Least 21 U.S. States During 2006
Newsworthy Cyanotoxin Events in the U.S.
Cyanobacteria Made the News in at Least 21 U.S. States During 2006
East Okoboji Lake, IA June 2000
= news report
After Graham, 2006
= reported
incident
At Least 35 U.S. States With Reports of Cyanotoxin Associated Poisonings

6. Photic Zone Sampling vs. Bloom Sampling
Cyanotoxin transport:
Intracellular:
Wind
Hydraulic
Bouyancy Regulation
Extracellular:
Hydraulic (Dissolved-Phase)
Particulate-Bound
Sampling protocol critical to ability to interpret data!
Higher concentrations of cyanobacteria and toxins more
likely in wind blown accumulations near shore.
Cheney Reservoir, KS, June 2003
Upper Gar, IA August 2006

7. Environmental Distribution of Cyanotoxins “The Quick Version”
Dissolved-Phase Toxin (Extracellular) = +
Particulate Toxin – meaning
depends on whether cells are lysed.
Total Toxin
Total Toxin = Extracellular Toxin + Intracellular Toxin + Particulate Toxin

8. Microcystins were Commonly Found in the Midwest by ELISA (1999 – 2006)
Integrated photic zone
samples.
78% (n = 359) of lakes had
at least one detectable
occurrence of toxins.
Total concentrations
ranged from:
< 0.10 to 52 ppb.
1999 – 2006 Jen’s historical work, with SDI kit and then Abraxis
Mozingo Lake, MO October 2001
After Graham and others 2004 and 2006

9. Total lakes: n=1150 for Microcystins
Randomly selected lakes for 2007 EPA National Lake Assessment - Photic Zone Sampling (
Total lakes: n=1150 for Microcystins
Total microcystin
samples collected in
photic zone in deepest
part of lake.
All samples were
analyzed by ELISA.
2 % of samples will
be analyzed by
LC/MS/MS for
confirmation.
Image from EPA 841-F

10. 2007 EPA NLA – Photic Zone Sampling Microcystins Were Found Throughout the United States Especially in the Upper Midwest.
% Overall Detections (with Reference Lakes and
Resampled Lakes): 32 % (401/1238)

11. 2006 USGS Midwestern US Cyanotoxin Reconnaissance – Targeted Cyanobacterial Blooms and Accumulations
Cyanobacterial blooms and accumulations in 23 midwestern
lakes (KS, MO, IA, MN) were targeted over a 1 week period in
August 2006.
Measurements included: water chemistry, cyanotoxin analysis by
ELISAs and LC/MS/MS (dissolved and total), taste-and-odor
compounds (SPME-GC/MS), chlorophyll a (fluorescence), and
phytoplankton ID.

12. 2006 USGS Midwest US Cyanotoxin Reconnaissance
During August 2006 all lakes (n=23) had detectable microcystins when ELISA and LC/MS/MS are combined, 30% had detectable Anatoxin-a, and 9% had detectable Nodularin-R.
ELISA (MRL = 0.10 ppb, 0.02 ppb, 0.04 ppb)
LC/MS/MS (MRL = ppb)
1. ELISA detections of Cylindrospermopsin were not reproduced by LC/MS/MS
2. ELISA detections for Saxitoxins could not be confirmed at this time. Still
working to include these compounds in our LC/MS/MS method.

13. 2006 USGS Midwest Recon Microcystins Were the Dominant Class of Cyanotoxins (ELISA - 23 lakes)
Upper Pine Lake, IA August 2006
Rock Creek Lake, IA August 2006

14. 2006 USGS MCR – Blooms and Accumulations Microcystins –LR and –RR were the Most Abundant Congeners and Microcystin–RR had the Highest Concentrations.
30%
% Detects
52%
39%
91%
61%
78%
65% 9%
Research 40 (13), pp
No detections above ppb for Cylindrospermopsin, Deoxycylindrospermopsin,
and Lyngbyatoxin-A.

15. 2006 USGS MCR Cyanotoxin Mixtures Were Commonly Found in Midwest Lakes and Reservoirs in 2006 by LC/MS/MS with Up to 9 Toxins Measured in One Sample.
Start on y axis with number of sample and then follow the bar to the x-axis for the number of toxins or vice versa. Example, 22 samples had at least 1 toxin and 21 samples had at least 2 toxins.

16. Comparison of ELISA Results for Microcystins
Photic Zone Sampling vs. Blooms and Accumulations
Higher Detection Frequencies and Higher Concentrations were Observed in Blooms and
Accumulations than in Photic Zone Sampling.
Study objectives dictate sample collection procedures (i.e. photic zone vs blooms and accumulations, etc.).

17. Take Home Message…
Cyanotoxins are present at levels that may be of concern for human health and ecological impact in some cases. Specifically, microcystins are found nationwide and are frequently encountered in the Midwest.
Anatoxin-a occurred in 30% of the 2006 USGS Midwest Recon at levels up to 9.5 ppb.
Predictably, higher detection frequencies and higher concentrations of toxins can be encountered in cyanobacterial blooms and accumulations versus photic
zone sampling.
In the 2007 EPA study (photic zone sampling), 9 (0.7 %) lakes exceeded WHO recreational guidelines (20 ppb) and 143 (12 %) lakes exceeded WHO drinking water guidelines (1.0 ppb) for microcystins.
In the 2006 USGS Midwest Recon (Bloom and Accumulation sampling), 4 (17 %) lakes exceeded WHO recreational guidelines (20 ppb) and 18 (78 %) lakes exceeded WHO drinking water guidelines (1.0 ppb) for microcystins. Microcystin-LR, one of the most toxic microcystin congeners, was detected most frequently (91 %).
LC/MS/MS results indicate that toxin mixtures may be fairly common.

18. Keith Loftin kloftin@usgs.gov (785) 832-3543
Jennifer Graham (785)
Additional Information Available on the Web:
Cyanobacteria -
USGS cyanotoxin sampling protocol: