The cyanobacteria bloom at Canal Point on Lake Okeechobee is more than twice as toxic as last year’s highest lake reading, when the “guacamole” bloom clotted the St. Lucie River. These results were published today by Florida DEP, based on samples taken last week:
This image (above) shows the location of a sample taken on August 1, where testing showed a total microcystin toxin reading of 815 micrograms per liter. That’s more than double the highest toxicity reading in the lake during the Toxic Summer of 2016, and more than 80 times higher than the World Health Organization’s threshold for restricting bathing in contaminated water (10 micrograms/liter).
In fact the WHO warns that concentrations of 50 micrograms/liter–16 times lower than the sample in Lake Okeechobee today–puts bathers at risk for long-term liver damage. Worse, it can go undiagnosed for years: “Experimental results indicate a hazard of cumulative liver damage by repeated microcystin intake (Fitzgeorge et al., 1994, see section 4.2.1), as can occur during a holiday with daily bathing at a recreational site with a high density of microcystin-containing cyanobacteria. Sub-acute liver injury is likely to go unnoticed, because signs of liver injury are only apparent after severe injury. “
But the DEP didn’t re-test the same area yesterday because the water wasn’t green anymore. So no samples were taken.
This may be standard protocol (established before the dangers of toxic algae were better understood) but it doesn’t make sense. Even when blooms aren’t visible, toxins persist. Human health risks persist. The DEP needs to change this policy, increase testing, and most important, start warning people to stay away from contaminated water.
The WHO guidelines mention research on the risks of even breathing toxins from fields irrigated with contaminated water at concentrations 40 times lower than today’s. Lakeside communities deserve to know about these risks before residents let their children near the water.