Sept. 1 2007 12:00 AM

From Wisconsin to Texas, from California to Maine, as the warmer weather moves in, most states become more watchful for 'toxic algae,' a blue-green variety that is potentially harmful. This is not the blue-green algae that you find on the health food store shelves, (good blue-green) but is in the same family group as toxic blue-green. Toxic blue-green has a nasty kick and, no, you can't tell the difference.

Understand that blue-green is what is known as a primary producer, and it is really at the bottom of the food chain; think of blue-green algae as power bars for zoo plankton.

Blue-green has been around for millions of years, and over that period of time has developed a way to regulate buoyancy. Being able to regulate its depth, blue-green can find the optimum feeding and lighting levels. With all conditions being right, i.e., temperature, light conditions, nutrients (phosphorus and nitrogen) you could have an algae bloom that comes to the surface. This even depends on time of day or wind direction. The basic premise in this country has been to get rid of waste water or rain water/runoff as soon as one can, moving it from point A here to point B somewhere else.

The basic glitch in this theory is that it takes nutrients along with it, such as yard fertilizers that use phosphorus and detergents. These are the largest urban contributor to the problem. However, agriculture adds its own to the mix.

We acknowledge that, but what has been overlooked is that one pound of phosphorus makes 300 to 500 pounds of algae. That fact alone is staggering when you consider the amount we as landscapers use to keep our neighborhoods nice and green. There are non-phosphorus fertilizers and many contractors use them, but the biggest complaint is that you lose the time-release factor that can be built in with phosphorus.

The health issue was explained to me like this: the runoff goes into the lake, providing food for the blue-green algae. In recreational lakes and reservoirs, people are involved with motorized vehicles, boats and jet skis. This is where the incompatibility occurs: because blue-green seeks its own level, when these mechanical devices stir up the water, it's like turning on a blender during the day. The catch is blue-green needs light to set its depth, and after being stirred up all day, when the sun goes down blue-green can not right itself and dies.

There are seven types of 'toxic' blue-green that are released when the plant dies. These toxins vary in amounts for each cell but are, endotoxins (skin), hepatotoxins (gasteroenteritis), and neurotoxins (neuromuscular).

Because the blue-green has been stirred up in the sunlight and has no way to right itself, it dies at night and gives off these toxic wastes (and odor) that cause problems for humans and pets. If you have been in contact with a water area that has blue-green and you develop a rash, hives, or allergy symptoms such as itchy watery eyes or scratchy throat, it may be the result of contact with blue-green algae. Did you get a mouthful, or maybe swallowed some?

If you develop stomach cramps, vomiting, diarrhea, fever, headache, severe muscle or joint pain, you need to call 911 and get to an emergency room. In extreme cases, contact can cause respiratory failure or death.


If an animal has been exposed, the symptoms are the same. Dogs are more susceptible because of being in urban environments, and as pets we take them to the lake to get out. Be sure to rinse your dog as soon as you can to remove the topical algae that may have stuck to the coat.

By design, retention ponds are just that -- they are made to catch nutrients and catch debris; however, it can be that by fine-tuning irrigation ponds we can have our water and aesthetics, too.

GPS guidance systems with variable rate nozzles are being developed for residential use. This, in tandem with surfactants to reduce water, herbicide, and fertilizer use, make them more effective and saving costs for us all.

Invest time to understand precision turf management, GPS systems and surfactants usage, and you could cut your water, herbicide and fertilizer use by 70 percent. If you can do that for your clients' bottom line or your bottom line, we can have our water and aesthetics too, and a lot less concern about the lean mean toxic blue-green.