The presence of toxic microcystin, produced by algal blooms, is a threat to human health when it contaminates water supplies. Recreational toxin indicates that there is enough microcystin in the water to harm humans who come in recreational contact with the water. Recreational contact is primarily skin contact, such as might occur while swimming or kayaking, as opposed to ingestion by drinking.
How was it scored?
Recreational toxin was used as an indicator in lake analysis. Data from the recreational season (Memorial Day to Labor Day) May 28–September 3, 2018 were analyzed. For each microcystin sample, the measurement was compared to the threshold on a pass/fail basis. Site scores were averaged into an overall region recreational toxin score.
The recreational toxin threshold used for the western Lake Erie basin analysis was the U.S. EPA recreational water quality criteria threshold 8 μg/L.