Marina Dock Age

MDA has already discussed different methods for controlling or eliminating blue-green harmful algae blooms. See “Ugly blue-green algae can harm marine environments” in the December issue.

The Centers for Disease Control and Prevention (CDC) have long recognized blue-green algae (or cyanobacteria) as a Harmful Algae Bloom (HAB) because of the effects it can have on people and animals. Blue-green algae has been found worldwide from Brazil to China, and Australia to the U.S. Also, according to CDC, poisonings date back to the 1800s.

Harmful effects of blue-green algae

The decomposition of blue-green algae releases four different toxins that can generally harm the nervous system, the liver, and the gastrointestinal system and increase tumor growth. CDC said these toxins are among the most powerful natural poisons known and found among the oldest fossils on earth. Common health effects with direct contact of high-level concentrations include:

• stomach and intestinal illness (abdominal cramps, nausea, diarrhea, and vomiting)
• allergic responses (itchy skin, red eyes, blistering, hives, or rash)
• respiratory problems (congestion, cough, wheezing, difficulty breathing, and pneumonia)
• liver damage
• neurotoxic reactions (tingling fingers and toes or muscle weakness, even paralysis)
• other possible symptoms: earache, agitation, headache, and vertigo.

Sometimes identifying symptoms of exposure in pets is more difficult. Common symptoms in animals include lethargy, vomiting, diarrhea, convulsions, difficulty breathing, or general weakness.

Blue-green algae is believed to have killed four dogs this summer from toxic exposure at Elk Creek in Roseburg, Ore., according to a Nov. 6 report from The Oregonian. The dogs went into convulsions after playing in the water and died almost immediately. Laboratory tests revealed in September from the Oregon State University’s Veterinary Diagnostic Laboratory confirmed that blue-green algae toxins definitively killed one of the dogs earlier that summer, according to a Sept. 10 (Org.) News-Review report. According to OSU tests, the toxins caused respiratory paralysis and led to death within 20 to 30 minutes.

Recognizing blue-green algae HABs

Cyanobacteria are naturally present microscopic organisms. However, under certain conditions they can form HABs, which occur when the algae begins growing rapidly. Within days a bloom can cause clear water to become cloudy. Soon after that, a water body infiltrated with harmful blue-green algae will exhibit the following characteristics:

foamy, scummy, or mat-like appearance

blue, bright green, brown, red, dark green, or black in color

usually floats to the surface, particularly toward the shoreline, and can be many inches thick

paint-like appearance or greenish yellow sludge appearance resembling pea soup

moldy or musty water smell, as the blue-green algae decomposes and releases toxins

The decomposition of these algae blooms have released phosphorus pollution (show here) ready to flow into Lake Okeechobee in South Florida.

Likely conditions for proliferation and exposure

Certain conditions can jump start blooms, such as:

• warm weather
• little wind
• intense sunlight
• stagnant water
• plentiful nutrients in the water (especially phosphorus and nitrogen)
• large rain events that wash agricultural or residential fertilizers into the water.

Typically, people and their pets are exposed to toxic water through skin contact or breathing air that contains cyanobacteria. Swimming, diving, or waterskiing have a high risk of direct exposure. Even recreational activities out of the water, such as fishing or boating can cause a dangerous exposure. Picnicking or walking on the shoreline even has exposure risks because the blue-green algae toxins can also be airborne. Drinking toxic water brings on the most harmful effects, and boiling water will not remove toxins.

What to do in case of exposure

If people find themselves or their pets in contact with discolored water that has scummy appearance, get out immediately. After direct skin contact, wash with freshwater and soap. Be sure to rinse all swimming suits as the toxins can get trapped in the materials. Wash pets’ fur thoroughly before they start to groom themselves. Ingesting the toxins will produce the worst effects, usually leading to the worst symptoms. Seek immediate medical attention if anyone experiences any of the symptoms described earlier.

Simple suggestions for keeping toxins low

In addition to the chemical and mechanical techniques described in the December issue, these simple practices can help prevent the development of blue-green algae:

• Do not rake leaves or lawn clippings in the water.
• Use phosphorus-free fertilizers, if possible, and keep all fertilizers or chemicals well away from the water.
• Caution boaters about shallow areas where their boat propeller may stir up the lake bottom.
• Maintain a buffer of natural vegetation around the water body to filter incoming pollutants.

A relatively unregulated problem gaining momentum

The U.S. Environmental Protection Agency (EPA) is also watching this growing HAB. As part of the Safe Drinking Water Act (SDWA), every five years, EPA must identify unregulated contaminants on the official Contaminant Candidate List (CCL). In September 2009, EPA published its latest CCL, which included cyanobacteria. Though blue-green algae is not subject to any current proposed regulations, its monitored presence by EPA may eventually require federal regulations under SDWA.

Anna Townshend is assistant editor of Marina Dock Age. She can be reached by phone at 847/647-2900 ext. 1308 or via e-mail at: atownshend@prestonpub.com.