Different shapes at monitoring sites indicate at which water depth the sample was taken. Squares are scum samples taken from the very top of the water column only when scum is visibly present. Circles are surface samples taken at approximately 0.75 m below the water surface. Triangles are bottom samples taken 1 m above the lake bottom. 

The color scale on this map follows public health advisory levels used by the Ohio Environmental Protection Agency. Green indicates that the toxin, microcystin, was detected in the water. Yellow indicates that a drinking water advisory is in effect for sensitive populations, because microcystin levels were measured greater than 0.3 ug/L. Orange indicates a drinking water advisory is in effect for everyone, because microcystin levels were greater than 1.6 ug/L . Red indicates that the public should avoid all body contact with the water, because  microcystin levels greater than 20 ug/L were detected. 

This data is produced by the Harmful Algal Bloom monitoring program, a joint effort by NOAA Great Lakes Environmental Research Lab (GLERL) and CIGLR with support from the Great Lakes Restoration Initiative. Monitoring data is provided “as is” and have not yet been subjected to quality control or quality assurance procedures. For data with QAQC, please refer to archive data. We work hard to post data from each week’s monitoring soon after collection, but there may be delays.