money Is Manatee County tap water safe to drink with algae bloom? Environmental group concerned
A Southwest Florida water quality advocacy group is raising concerns about the safety of Manatee County’s drinking water due to blooms of blue-green algae.
A bloom is currently happening in the Lake Manatee Reservoir, which supplies about two-thirds of county drinking water.
In a statement on Monday, county officials said that the algae may cause county water to have a musty odor or taste, but the water is safe to drink.
“Current conditions favor a bloom, and tests conducted over the past several weeks indicate the presence of blue-green algae at elevated concentrations,” the county said Monday. “While the odor or taste may be noticeable, there are no known health effects caused by the presence of these compounds.”
Suncoast Waterkeeper is questioning that claim.
“It is crucial to remember that there is currently no Safe Drinking Water Act limit for the cyanotoxins produced by blue-green algae,” Suncoast Waterkeeper said in a press release on Wednesday.
“So, while the water may not be ‘harmful’ to drink from a regulatory perspective, we have no idea whether the water is harmful according to health standards,” the statement continued.
In an email on Thursday, county officials identified the type of algae blooming in Lake Manatee as Anabaena (also known as Dolichospermum). The algae regularly blooms in Lake Manatee, according to county officials.
While algae in the genus Anabaena can produce toxins, county officials say they have never detected any from the species present in the lake.
“We have many years of experience with this algae, and we have tested for toxins repeatedly and never detected any. Even if toxins were produced, our water treatment process is capable of removing those toxins,” the county said Thursday.
Manatee County Utilities has not tested for toxins during this bloom event. County officials said that this year’s bloom is worse than in recent years “but still within the norm.”
What to know about cyanotoxins in drinking water
The term “blue-green algae” refers to several types of bacteria, called cyanobacteria, that typically grow in fresh water bodies in Florida. Cyan comes from the Greek word for the color dark blue.
Similar to red tides that occur in salt water, they are considered “harmful algal blooms” because of the powerful toxins they can produce.
The Environmental Protection Agency says conventional water treatment “can generally remove intact cyanobacterial cells and low levels of cyanotoxins from source waters.”
“However, water systems may face challenges in providing drinking water during a severe bloom event when there are high levels of cyanobacteria and cyanotoxins in source waters,” the agency says.
The agency has recommended guidelines for local governments to issue health alerts when cyanotoxins pass certain levels, but the toxins are not federally regulated.
Not all blooms of blue-green algae are harmful or produce cyanotoxins. But if cyanotoxins are present, people can become sick from breathing them in, swallowing contaminated water, eating contaminated food or skin contact, according to the Centers for Disease Control and Prevention.
The EPA says that drinking water with elevated levels of cyanotoxins can result in upset stomach, vomiting and diarrhea, as well as potential liver and kidney damage.
Infants, young children, pregnant women, the elderly and people with certain medical conditions are at higher risk for health effects from exposure.
Cases of illness from drinking water contaminated with cyanotoxins are not well-documented in Florida, but they have been confirmed around the U.S. and the world. In 2021, residents of West Palm Beach reported getting sick after cyanotoxins were found at elevated levels in the city’s water supply.
Most drinking water in Florida is sourced from underground aquifers, but it is supplemented with surface water sources like lakes and rivers.
Worsening blooms could threaten drinking water quality
Harmful algal blooms are thought to be becoming more common in Florida, which could pose increasing risks to surface water supplies. One contributing factor is nutrient pollution from human sources that can increase the intensity and duration of algae growth.
“Reducing nutrient pollution across the Suncoast must be a top priority, because these harmful algal blooms are chipping away at our quality of life and threatening our health,” said Suncoast Waterkeeper executive director Abbey Tyrna in a news release.
The organization has a citizen water quality effort called Eyes on the Suncoast that encourages residents to report signs of pollution, and in July it will launch a boat patrol program to further monitor local waterways.
Suncoast Waterkeeper also conducts water quality testing at locations not regularly monitored by the state. The group has not sampled at Lake Manatee, and recent water sample results for the lake were not available in the state’s database.
The water body is listed as impaired because it does not meet state water quality standards.
What to do if you’re concerned about your drinking water
While public water filtration systems can generally remove cyanotoxins at low levels, it’s possible to take extra steps to purify your water at home.
According to the EPA, reverse osmosis can generally remove the most common types of cyanotoxins from water, as well as other toxins that are unregulated or present at low levels.
Water should not be boiled if there is a risk of cyanotoxins, as this can increase the levels of toxin present, the EPA says.
Additional resources:
Residents can report water quality issues to Manatee County Utilities at 941-746-3020.
The EPA’s Safe Drinking Water Hotline, at 1-800-426-4791, can answer questions about drinking water safety.
Environmental Working Group’s Tap Water Database provides information about contaminants that may be in your drinking water and how to choose the right filtration system to remove them.
