ATLANTA — The Centers for Disease Control is seeking public comment on a proposed study of persons exposed to algae in Lake Okeechobee.
CDC-2019-0079, published Sept. 17 in the Federal Register, proposes a collection project titled “Aerosols from cyanobacterial blooms: Exposures and health effects in a highly exposed population.”
CDC will accept written comments up to Nov. 18, 2019.
Algae blooms are a problem in lakes nationwide, according to the CDC. Anglers who regularly fish Lake Okeechobee question the assumption those fishing the Big O are a “highly exposed population.”
Why was Lake Okeechobee chosen? The CDC study is the result of a May 7 closed-door meeting where Congressman Francis Rooney hosted “selected” federal, state and Lee County area leaders to discuss harmful algae blooms. Gov. Ron DeSantis was at that meeting. Members of the press were not allowed at the meeting, which was closed to the public. Protesters outside the meeting held signs calling the closed-door meeting “dirtier than polluted water.”
According to the proposal: “CDC will conduct a study of 50 people highly exposed to cyanobacterial harmful algal blooms to assess exposure of CyanoHAB aerosols and determine if exposure is associated with health symptoms and/or outcomes.”
Previous work done in Wisconsin demonstrated low but measurable concentrations of hydrogen sulfide and methane, both respiratory irritants in the air near dense and decomposing cyanobacterial blooms, according to the proposal.
The CDC seeks 50 persons age 18 or older who have “extensive exposure to CyanoHABs on Lake Okeechobee,” the report states. The participants will take part in a survey that will run March-October 2020.
According to the notice, the CDC will notify potentially interested participants using posted flyers with a phone number to call. CDC will use a phone-based screening survey to choose 50 participants from among the applicants. Participants will be asked to provide baseline data three times: at the start, in the middle and at end of the study period. During the interviews, participants will complete a survey, do a pulmonary function test, provide urine and nasal swabs for analysis of cyanotoxins and provide blood samples for analysis. Before and after each of 12 boat trips, study participants will complete the survey and provide urine and nasal swab specimens. Study participants will also be asked to donate one fish from each trip, to be analyzed for cyanobacterial toxins, along with the GPS Exchange Format file (GPX) of the boat’s travels.
“Good luck with finding 50 volunteers,” said Mike Krause of Okeechobee Fishing Headquarters. He explained that while some anglers may be willing to participate just to prove there are no health issues for those fishing the Big O, others are concerned that no matter what the study eventually finds, the national media will use the fact that CDC is studying the lake to put Lake Okeechobee in a bad light.
Mr. Krause said the federal funding might be better used to study another lake since algal blooms are a problem nationwide.
If the CDC does find enough volunteers to conduct the study on Lake Okeechobee in 2020, there may not be sufficient algal bloom exposure to study.
The proposal makes the assumption that there will be extensive HABs on the Big O to which the 50 volunteers would be exposed during the test period.
Algal blooms are common on Lake Okeechobee — many species of algae and cyanobacteria (often called blue green algae) are part of the lake’s natural ecosystem. During hot summer months, if there is not a lot of water movement, excess nutrients such as phosphorus and nitrogen in the water can be conducive to the rapid reproduction of the microscopic algae and/or cyanobacteria into a visible “bloom.”
The size algal blooms on Lake Okeechobee varies from year to year. The species of algae and cyanobacteria in the blooms can also vary. According to the U.S. Geological Survey, 28 species of cyanobacteria have been documented in the Lake Okeechobee Waterway, which includes the St. Lucie River, the St. Lucie Canal, Lake Okeechobee and the Caloosahatchee River. About 25% of the species of cyanobacteria are capable of producing toxins. But species capable of producing toxins do not always produce toxins.
In the summers of 2016, 2017 and 2018, when high toxin levels were reported in blue green algal blooms in the St. Lucie and the Caloosahatchee rivers, Florida Department of Environmental Protection samples found toxin levels were low in Lake Okeechobee.
It was obvious even to the casual observer that the algae blooms in the lake in 2016, 2017 and 2018 were not as dense or persistent as the blooms in the coastal waterways. In the lake, algal blooms are often feathery and ephemeral. The cyanobacteria may rise and fall in the water column. Even when National Atmospheric and Oceanic Administration (NOAA) imagery indicated a concentration of cyanobacteria in a particular part of the lake, boaters reported they could not find any visible blooms.
Scientists are still trying to figure out just what triggers cyanobacteria to produce toxins. One factor that might be involved include the levels of nitrogen in the water. A 2016 study in the St. Lucie waterway found toxin levels were higher in areas with higher levels of nitrogen in the basin runoff.
During the summer of 2019, algal blooms were minimal in the lake, and most were mixtures of various species of algae and cyanobacteria with no toxins or barely detectable low levels of toxins. There were a few bloom areas that tested positive for toxins and two short-lived toxic blooms trapped in water control structures. (In one of those cases, FDEP personnel who took the water samples reported what appeared to be a lot of bird droppings, which could account for higher nitrogen levels.)
One study planned for the summer of 2019 by the U.S. Army Corps of Engineers had to be postponed because they could not find an algae bloom that lasted long enough to run the experiment.
The CDC proposal suggests that motorboats and jet skis can aerosolize water along toxins which might be breathed in. While Lake Okeechobee anglers might enjoy the exciting “blast off” at the beginning of a big bass tournament, the major launching sites for tournaments have not historically been areas with algal blooms. The primary recreational activity on Lake Okeechobee is fishing, not jet skiing or water skiing. Even if the summer of 2020 brings algae blooms in Lake Okeechobee, just how much the 50 volunteers on the Big O would be exposed to aerosolized matter from a bloom is unknown.
To make a public comment online, click HERE.
Comments may also be mailed to: Jeffrey Zirger, Information Collection review Office, Centers for Disease Control and Prevention, 1600 Clifton Road, NE, MS-D74, Atlanta, GA, 30329.