Health Note from DNR

I am an environmental toxicologist in the Water Quality Standards Section at the Wisconsin Department of Natural Resources in Madison, and I am currently serving as the coordinator of a statewide blue-green algae (BGA) monitoring project. The purpose of this message is to notify you that we have detected high concentrations of blue-green algae in a sample collected from the following lake in your county:

1) Lake Koshkonong, collected on 06/29/2005
Aphanizomenon sp. at 39,500 filaments/mL

Because the number of cells in the average filament ranged from approximately 15 to 50, the density of blue-green algae in this sample is very likely over the World Health Organization guideline of 100,000 cells/mL.

This species of blue-green algae is capable of producing toxins, including anatoxin-a, a neurotoxin.

The purpose of the DNR's monitoring project is to investigate the frequency, severity, and duration of BGA blooms, including information on which species of blue-green algae are present and their concentrations. In a select number of samples we will also determine the concentrations of specific toxins: anatoxin-a (a neurotoxin), microcystin (a hepatotoxin), and cylindrospermopsin (another hepatotoxin).

Unlike the DNR's beach monitoring program for bacteria, the blue-green algae monitoring program is NOT designed to provide real-time information on the presence of BGA or blue-green algal toxins, and only a very limited number of surface waters can be monitored in each region of the state. However, when DNR receives information from the SLOH that high concentrations of BGA are present or that a blue-green algal toxin has been detected, this information will be shared with the local public health agency through the county public health officer. Only DHFS or the local public health agency has the authority to close a beach.

Should you decide to close any beaches or post any advisory signs, I've attached a copy of a generic sign that can be modified for your county, laminated and posted. Last year, beaches were temporarily closed at Lake Menomin and Tainter Lake in Dunn County, Crystal Lake and Lake Kegonsa in Dane County, and Twin Valley Lake in Iowa County, based on the results of DNR sampling.

Additional information on blue-green algae and what people can do to protect themselves from exposure is listed below. Please feel free to contact me if you have any questions.

Sincerely, Elisabeth Harrahy, Ph.D.
P Elisabeth Harrahy, Ph.D. Environmental Toxicologist Water Quality Standards Section Bureau of Watershed Management Wisconsin Department of Natural Resources
phone: (608) 264-6260
fax: (608) 267-2800
e-mail: Elisabeth.Harrahy@dnr.state.wi.us <>

Background Information
-blue-green algae are actually photosynthetic bacteria (a.k.a. cyanobacteria)

-can increase in number to "bloom densities" in surface waters with high concentrations of nutrients, particularly phosphorus

-most species are buoyant and when their densities become high, they can accumulate on the surface and form scum layers, mats, or blobs

-blooms tend to grow when there is a lot of sunlight, the temperature is warm, the water is shallow and there is little wind

-sometimes when the wind kicks up, blue-green algae will pile up on the windward side of the lake

Possible Effects on the Environment

-blue-green algae are not usually eaten by fish and invertebrates, so when they become high in density and outcompete the more palatable, true algae, they can have indirect effects on the food chain

-as a bloom dies, it can decrease the amount of oxygen in the water, which can result in fish kills

Possible Effects on People

-many species of blue-green algae are capable of producing toxins -dermatotoxins: skin rashes, gastrointestinal disturbances, headaches, eye,
nose and throat irritation

-hepatotoxins: liver damage, possibly liver cancer, death (at high
concentrations)

-neurotoxins: seizures, paralysis, respiratory failure, death

-not all species that are capable of producing toxins produce them all the time

Measures People Can Take to Protect Themselves

-avoid swimming or recreating in water that looks like "pea soup", green or blue paint, or that has a scum layer or puffy blobs floating on the surface

-do not let pets or livestock (BGA have been known to kill cattle also) swim in or drink such water -do not let children play with or in scum layers, even from shore -do not treat surface waters that are experiencing blue-green algal blooms with any
herbicide or algaecide-- toxins are released into the water when blue-green algae cells die

-always take a shower or bath after coming into contact with surface water
Measures People Can Take to Help Reduce Future Blue-Green Algae Blooms

-maintain native vegetation along shorelines as buffer areas -minimize activities that result in erosion -reduce the amount of fertilizer used on lawns

-please see DNR web site for more information
-http://dnr.wi.gov/org/water/wm/wqs/bgafaq.pdf -http://dnr.wi.gov/org/water/wm/wqs/bgabrochure.pdf

-contact Dr. Elisabeth Harrahy (DNR) for general information on BGA -contact Dr. Mark Werner (DHFS) for information on human health effects