State health officials are urging the public to avoid a South Florida canal until further notice after detecting the presence of toxic blue-green algae in the waterway.

The Florida Department of Health in Miami-Dade County (DOH-Miami Dade) issued the advisory on Wednesday for the Twin Lakes Canal in South Miami, saying that water sample testing is currently underway.

Neighbors spoke to CBS News Miami after the DOH posted signs this week near Southwest 65th Avenue and 68th Street amid warnings about blue-green algae that may be in the canal.

Dale Andre told CBS News Miami that the signs alone were "very concerning."  

" I have heard a lot about this in other areas of the state and read about it, but now we have it in our own canal -- we all have to pay attention to our environment," he said. "This is right here and in our backyard."

"You are always concerned when this happens in your neighborhood," added Neighbor Joel Kolker. "Who wants poisons in your area? I think we should really be concerned about our pets." 

According to health officials, blue-green algae have the potential to produce toxins and since environmental conditions can change at any time, it's important to exercise caution, even if the presence of toxins has not yet been confirmed.

Residents and visitors are advised to take the following precautions when going to the Twin Lakes Canal and other affected waterways:

• Do not drink, swim, wade, use personal watercraft or come into contact with waters where there is a visible bloom.
• Wash your skin and clothing with soap and water if you come into contact with algae or discolored or unpleasant-smelling water.
• Keep pets and livestock away from the area to avoid any contact with the water, as waterways where algal blooms are present are not safe for animals. Pets and livestock should use an alternative source of water when blooms are present.
• Do not cook or clean dishes with contaminated water, as boiling water will not eliminate the toxins.
• Eating filets of healthy fish caught in freshwater lakes experiencing algal blooms is safe; however, you must rinse fish filets with tap or bottled water, throw out the guts and cook the fish thoroughly before consumption. Do not eat shellfish caught in waters experiencing algal blooms.

Foul-smelling and discolored water are signs of algal blooms

According to the DOH-Miami Dade, blue-green algae are a type of bacteria that is common in Florida's freshwater environments.

A bloom occurs when a rapid growth of algae leads to an accumulation of individual cells that discolor the water and often produce floating mats that emit unpleasant odors, often appearing as scum, foam or paint on the surface in various colors.

Some environmental factors that contribute to blue-green algal blooms are "sunny days, warm water temperatures, still water conditions and excess nutrients," the DOH-Miami Dade said. Blooms can appear year-round but are more frequent in the summer and fall, and though they may not always be visible, they can still be present in the water.

Blue-green algae are harmful to humans and animals alike, experts say

Many types of blue-green algae can produce toxins that are detrimental to humans, animals, and the ecosystem as a whole.

The DOH-Miami Dade said that sensitive individuals, such as children, the elderly and those who are immunocompromised, may still be at risk even at low concentrations and should avoid any exposure.

Philip Stoddard, a professor emeritus with Florida International University's Department of Biological Services and who served as South Miami mayor from 2010 to 2020, lives in the area and told CBS News Miami that he has seen the blue-green algae, also known as "cyanobloom," just north of where the signage appeared. 

"When you see a cyanobloom, you see that the entire water's surface is covered with a pretty uniform film. Some cyanobacteria, some of the time, produce amino acids and neurotoxins, and that can be nasty. It can also biologically accumulate through the food chain," he said.

Stoddard added that the first thing people should do is prevent their dogs from swimming or drinking infected water.

"The dogs will wade in it or take a lap," he told CBS News Miami. "I would not use the water for irrigation and I would not fish out of it."

How to check the current water statuses and report possible algal blooms

The DOH-Miami Dade said that the Florida Department of Environmental Protection (DEP) and its partners collect algae samples from reported bloom locations. After samples are tested, the toxin results can be viewed on Protecting Florida Together's website or on the DEP's Algal Bloom Dashboard. You can also receive updates by subscribing to Protecting Florida Together here.

To learn more about how to spot algal blooms, visit Protecting Florida Together's website. If you spot one, you can report it to the DEP online or by calling (855) 305-3903.

If you've come into contact with blue-green algae or any aquatic toxins, call the Florida Poison Information Center at (800) 222-1222. If you believe your pets or livestock have been exposed, contact your veterinarian.

The DOH-Miami Dade said that all dead, diseased or abnormally behaving fish or wildlife should be reported to the Florida Fish and Wildlife Conservation Commission (FWC) online or by calling (800) 636-0511. All other health questions and concerns about blue-green algae can be answered by the DOH-Miami Dade at (305) 324-2400.