A recent News-Press article (“Well-known FGCU professor accused of downplaying blue-green algae by water advocate“) overlooks the principal barrier to public understanding of Florida’s persistent blue-green algae – the calibration of exposure to risk.

First, there are several peer-reviewed studies that link human mortalities and related risks to cyanobacteria (blue-green algae) exposure around the world, and in Florida, including a cluster of nonalcoholic liver disease near Lake Okeechobee.

Secondly, the takeaway from such media stories – that mortality is the only public health risk worth considering – is in fact under-informing the public of the potential dangers. Yes, cyanotoxins are extremely potent in high concentrations, particularly if ingested. But to suggest that directly drinking cyanobacteria-laden waters is the only risk worth being concerned about is careless, and disregards numerous public health policies.

The EPA has recreational (contact) exposure guidelines and swim advisories that are separate from their drinking water standards. In accordance with this guidance, and as rightly stated in the article, the Florida Department of Health has issued numerous cyanotoxin advisories throughout the Okeechobee and Caloosahatchee systems in 2023. This is widely accepted public health policy that seems to be getting dismissed regularly by various experts being interviewed in local media. The objectives of these advisories are to protect the public from contacting potential toxins while swimming, boating, paddling, and eating shellfish and fish from affected waters.
Health Alert Blue Green Algae warning sign
In 2023, we have witnessed the largest cyanobacteria bloom experienced on Lake Okeechobee in the last four years. NOAA / NCCOS satellite data has tracked 98 days of a measurable bloom from space, averaging in size at 174 square miles and peaking (so far for the year) at about 500 square miles.

Regarding longer term risk assessment, scientific research has yet to determine how much exposure to the various toxins (primarily microscystin and BMAA) produced by blue-green algae increases the risk of developing a number of diseases, including neurological conditions such as ALS, Parkinson’s and Alzheimer’s. However numerous studies have established that exposure to cyanotoxins elevates the risks of developing these diseases.

There have been documented cases of acute and sudden “blue-green algae deaths” of dogs that have consumed water infested with blue-green algae. But one significant barrier to public understanding of the risks involved for humans is an appreciation of the latency period between exposure and the on-set of disease, which could be more than a decade.

blue green algae bloom in local waterway
Clearly, it is inaccurate to claim that “if you smoke a cigarette, you will die.” But we have come to understand that smoking significantly elevates the risk of certain diseases, including several forms of cancer.

Similarly, this has been a priority of Calusa Waterkeeper – to warn people that exposure to the toxins produced by blue-green algae involves risks of developing terrible debilitating illnesses.

In addition to increased public understanding of the threat of Florida’s persistent blue-green algae problem, we seek better public policies and greater enforcement of anti-pollution regulations to inhibit the growth of blue-green algae and, thereby, minimize the risk of these debilitating illnesses to the people of southwest Florida.

We invite experts from all viewpoints to join us in an open discussion of calibrating the potential health risks and communicating them accurately to the public.

Charles Avery
President of the Board
Calusa Waterkeeper