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Harmful Algal Bloom (HAB) Monitoring

Harmful Algal Bloom (cyanotoxin) monitoring results in Ohio for water bodies used by public water systems. The only data included on this site are microcystin, cylindrospermopsin, saxitoxin, and anatoxin-a.


Public Water Systems monitor for cyanotoxins as required per the HAB Rules (finalized June 1, 2016) and the 2015 Harmful Algal Bloom Strategy. Ohio EPA also monitors inland lakes for cyanotoxins in watersheds being assessed for their Total Maximum Daily Load (TMDL). Ohio EPA-collected samples are analyzed at Ohio EPA's Division of Environmental Services (DES). Data sampled by Public Water Systems are analyzed at either their own lab or a commercial lab.

Access and Use Constraints

Acknowledgement of the Ohio Environmental Protection Agency, Division of Drinking and Ground Waters as a data source would be appreciated in products developed from these data, and such acknowledgement as is standard for citation purposes. Users of this data should be aware that inconsistencies and inaccuracies may exist if these data are compared to data from other time periods due to changes in methods of data collection and mapping.