waskington state lake images
WATERLINE - June, 2013

Ecology’s Freshwater Algae Control Program helps identify and publicize harmful blooms

by Lizbeth Seebacher, Department of Ecology

dept of ecology WA logoBlue-green algae or cyanobacteria can cause blooms on Washington’s lakes throughout the year, but blooms occur most often during sunny, dry weather in late summer into early fall. Some blooms can become toxic when the cyanobacteria produce toxins that can cause illness and even death in animals. Even if blooms are not toxic, they can look unpleasant, smell strongly, and seriously impact recreational lake use. The Department of Ecology administers a program that can help you identify harmful algae, learn where blooms are occurring, and stay informed.

The Washington State Legislature established funding for Ecology’s Freshwater Algae Control Program (FACP) in 2005. The program is funded by vessel registration — one dollar from each fee goes to the Freshwater Algae Control account. This generates about $500,000 every two years, with which the Department of Ecology manages the FACP.

How does the FACP help with toxic algae blooms?

Small grants are offered each year to state and local governments to help address freshwater algal issues in their lakes. Program funds also support a toxicity testing program that identifies the algal species present in samples submitted. The program focuses on four primary toxins produced by the most common cyanobacteria species listed below.

 Table 1.  Cyanobacteria toxins and the organ they affect in mammals

Toxin Group Primary Target Organ Genera Known to Produce Toxin
Microcystins* (Most commonly detected freshwater algal toxin) Liver Microcystis, Anabaena, Planktothrix (Oscillatoria), Nostoc, Hapalosiphon, Anabaenopsis
Anatoxin-a* (Second most commonly detected freshwater algal toxin) Nerve synapse Anabaena, Planktothrix (Oscillatoria), Aphanizomenon
Cylindrospermopsins (several detections in Washington’s freshwaters) Liver Cylindrospermopsis, Aphanizomenon, Umezakia
Saxitoxins (Cause paralytic shellfish poisoning in marine waters – uncommon in freshwater, but found above guideline levels in Pierce County’s Waughop Lake in 2009 and detected there every year since.) Nerve axons Anabaena, Aphanizomenon, Lyngbya, Cylindrospermopsis

*Ecology tests primarily for these algal toxins in Washington blooms. Cylindrospermopsins and saxitoxins have been tested for in 30 lakes (in Pierce, King and Snohomish Counties) under a grant funded by DOH and the Centers for Disease Control and Prevention (CDC).

The FACP also offers a searchable on-line database where you can find algal identification information and results of toxicity testing. The new Washington State Toxic Algae Freshwater Algae Bloom Monitoring Program website provides historical and current toxicity data at https://www.nwtoxicalgae.org/Default.aspx.

Program staff also maintain a freshwater algae electronic mailing list. Sign up at http://www.ecy.wa.gov/programs/wq/plants/algae/ListServe.html to get the latest toxicity results and other current information.

Protecting lakes, pets and people

In addition to the programs listed above, the FACP works with the Washington State Department of Health (DOH) to answer health-related questions about algal toxicity, develop recreational guidelines for toxic algae blooms, provide education materials, warning signs and more. Ecology and DOH websites offer information about freshwater algae, management methods, and human and pet health risks from toxic cyanobacteria blooms.

The program also helped set recreational safety guidelines for toxic cyanobacteria blooms in Washington. Working with Ecology, DOH developed a statewide strategy to help local health authorities decide what toxin concentrations should trigger actions to protect human health. DOH established recreational guidance values for microcystin at 6 μg/L and anatoxin-a at 1 μg/L. A second project provided guidance for two other toxins, cylindrospermopsin at 4.5 μg/L and saxitoxin at 75 μg/L.

DOH also identified events that trigger health advisories or lake closures and produced signs, available to local health districts, to post at affected lakes. DOH developed a three-tiered protocol for actions to implement in waterbodies experiencing different levels of toxic algae blooms. Finding a bloom triggers Tier I precautions, which means the local health department posts a Caution sign and tests the bloom for toxicity through Ecology’s program. If the results of those tests are higher than the guidelines noted above, Tier II protocols apply and a Warning sign is posted, with the lake tested every week until toxicity levels subside. If the lake has a history of high toxicity or if there are reports of illness or pet death, the health department may choose to post a Danger sign and close the lake until testing shows the bloom has dissipated and toxicity levels have abated.

Lake watchers should be aware that, unfortunately, a bloom that is not toxic one day may become toxic the next. These blooms often contain several genera capable of producing toxins. These can be even more toxic than some more familiar poisonous compounds (Table 2).

Table 2.  Comparison of blue-green algae toxins to the toxicity of other known poisons

Algal Toxins LD 50 μg/kg Known Poisons LD 50 μg/kg
Saxitoxin 9 Ricin 0.02
Anatoxin-a (s) 20 Cobra toxin 20
Microcystin LR 50 Curare 500
Anatoxin-a 50 Strychnine 2000

What are we learning about toxic blooms from the program?

In 2012, 65 water bodies (lakes, ponds, creeks, etc.) were tested (some more than 25 times) for the two most common toxins, microcystin and anatoxin-a. Just over 20 of those waterbodies tested above the recreational guidelines for microcystin and another seven tested over the recreational guideline for anatoxin-a. See below for lakes that tested highest for these toxins in 2012.

Lakes with the highest toxin levels in 2012

Lake and County Microcystin μg/L & Month Detected Lake and County Anatoxin-a μg/L & Month Detected
Howard Lake / Snohomish 2700 μg/L / August Clear Lake / Pierce 706 μg/L / January
Wauhop Lake / Pierce 1170 μg/L / August Anderson Lake / Jefferson 619 μg/L / July
Kitsap Lake / Kitsap 501 μg/L / September Rufus Woods Lake / Douglas 110 μg/L / July
Green Lake / King 419 μg/L / October Lake Goss / Island 2.24 μg/L / November
Lake Ketchum / Snohomish 417 μg/L / August

So far, the data tell us:

  • We have a significant number of lakes with cyanobacteria blooms throughout the state, with most in the Puget Sound region.
  • The most prevalent toxins produced are microcystin and anatoxin-a.
  • Most of the more severe blooms are found primarily in late summer or early fall.
  • Some lakes, like Anderson Lake, can produce toxic blooms throughout the year.
  • Lakes with a history of toxic blooms often continue to produce toxic blooms each year.

How are organizations around the state trying to address toxic algae blooms?

FACP grant projects funded for the next fiscal year include algae control implementation at Lake Ketchum, work to determine the anatoxin-a threat to Puget Sound lakes, a water quality investigation and installation of floating wetlands at Hicklin Lake and nutrient data collection in Jefferson County. Activities funded by these grants range from implementing an alum treatment to studying the genetic makeup of algal species in a lake that produces some of the highest anatoxin-a toxicity levels in the country to experimenting with floating wetlands to reduce nutrients and improve water quality. Learn about past projects from the Final Offer and Applicant List at http://www.ecy.wa.gov/programs/wq/plants/algae/grants/index.html.

For more information on Ecology’s Freshwater Algae Program, contact Lizbeth Seebacher at Lizbeth.Seebacher@ecy.wa.gov.