2004 Marks New Era in Toxic Algae Awareness

2004 Marks New Era in Toxic Algae Awareness

Although toxic blue-green algae has always been a potential threat to public health, it became an issue of much greater concern in Nebraska in 2004.

The state’s awareness of the issue became sharply focused in early May, when the Department of Environmental Quality (DEQ) received reports of a dog dying after drinking water containing algae from Buccaneer Bay, a residential sandpit lake near the Platte River, south of Omaha. The autopsy conducted on the dog and water samples taken from the lake both confirmed high levels of the algae toxin Microcystin.

This toxin is found within certain strains of cyanobacteria (cyanobacteria is commonly referred to as blue-green algae, although technically it is not a true algae). During this same time frame, DEQ received reports from a few other lakes near Buccaneer Bay, regarding sick animals and the presence of large algae blooms.

State’s Initial Response
Staff from DEQ met with officials from Nebraska Health and Human Services, Nebraska Game and Parks Commission and the University of Nebraska Cooperative Extension to develop an immediate strategy to define the problem and warn the public of potential hazards. The state immediately contacted the media and local health officials to inform the public that there was a potential health threat at the lakes where initial problems were discovered. DEQ purchased lab testing equipment to more quickly determine the amount of toxins present in Nebraska’s lakes. The three agencies also developed a protocol to determine when and where to conduct sampling. They established a weekly sampling schedule at those locations that were determined to be high priorities. During the outdoor recreation season and throughout the fall, samples were taken every Monday, and results made public by Friday of the same week.

In addition, the University of Nebraska Cooperative Extension provides sampling kits for individuals who wanted to test their own lakes, at sites that were not ranked as priority sites by the state. Individuals who receive the kits collect their own samples and send them to the University. The University provides an analysis of the types and densities of blue-green algae present in the samples. Those samples with dense concentrations of blue-green algae are then sent to DEQ’s Biolab to test for the levels of Microcystin toxins. (For more information on this program, contact the University at 402-472-7783 or 3305).

Health Alert System
The three state agencies also developed a Health Alert system for those lakes that had toxins at a level that is considered a potential health risk. At sites where samples of the toxin Microcystin are measured at or above 15 parts per billion, a Health Alert is issued. When a Health Alert is in effect, the public is prohibited from full-body contact activities, such as swimming, water skiing, jet skiing, sailboarding and tubing. However, recreational boating and fishing are permitted in those areas, as long as the public avoids situations that could possibly involve the ingestion of water. People can still use the areas for camping, picnics, and other outdoor activities.

The state also urges the public to pay particular attention to small children and pets, and prevent them from having contact with the water in those areas where a Health Alert has been issued.

Numerous Lakes Placed on Alert
Over the 2004 recreational season, which extended from May 1 through September 30, Health Alerts were issued at 24 lakes in Nebraska. Some alerts were issued for only one week, because readings taken the following week indicated that toxin levels had subsided. However, at some of the lakes, the problems persisted or recurred. Five lakes were on alert status for six weeks or longer.

Because this is the first year that detailed data has been collected on toxin levels in Nebraska’s lakes, the state does not have definitive evidence that the levels were higher than previous years. However, anecdotal evidence suggests that an unusual toxic algae problem existed in 2004. In addition to the reports of dog deaths in May, the state received numerous calls from people becoming ill at Pawnee Lake near Lincoln in mid-July. The calls were from people who had been swimming in the lake less than a week before a Health Alert was issued there. Altogether, about 50 cases were reported to the Nebraska Health and Human Services System of individuals who experienced skin rashes, nausea and other gastrointestinal disorders after reportedly being immersed in or swallowing lake water. Toxin levels at Pawnee Lake continued to be high throughout the entire recreational season.

“The number of calls we received reinforced what we were already telling the public – this can be a real threat to public health, and needs to be taken seriously,” said Dr. Tom Safranek, state epidemiologist. “Simply put, if there’s a sign posted saying that a lake is under a Health Alert for toxic algae, people need to stay out of the water.”

Causes, Cures and Predictions
Many questions were raised by the many Health Alerts issued in 2004, such as: What causes toxic algae? Why does it seem worse this year? What can be done to stop or prevent it? Will it continue to be a significant problem in future years?

The answers to these questions are not simple, and state and University officials, as well as their counterparts in other states and the federal government, are seriously examining these issues.

Many strains of green and blue-green algae occur naturally in Nebraska’s lakes. The right combinations of sunlight, temperature, low water levels, and nutrients in the water are believed to allow certain strains to dominate at various times. There can also be man-made contributions to the problem – the nutrient levels in the water can be affected by runoff that contains fertilizers, or seepage from septic systems, for example. It is likely that the right combination of environmental conditions in 2004 caused some of the toxic strains of blue-green algae to be more dominant than normal at some Nebraska lakes.

In order to reduce the occurrence of blue-green algae blooms, the first line of defense is identifying and curtailing any man-made contributions to the problem, said John Lund, Supervisor of DEQ’s Surface Water Unit. The University of Nebraska Cooperative Extension has been working with DEQ to define these potential contributors to lake problems, and to work with communities to find solutions.

In addition to reducing man’s contribution to the problem, state and university officials are also examining various treatment options. Although there are chemical treatment options that can reduce algae growth, those options are not necessarily practical if a lake is experiencing an algae bloom, Lund said. The chemicals can effectively kill algae, but when the algae dies, it releases the toxins into the water. In other words, treatment has the potential of causing a sudden increase in toxins in a lake, if the treatment takes place when there is already a large algal bloom. The use of chemical treatment as a method of prevention (conducted prior to the usual season for algal blooms) is still being discussed.

The general consensus of those involved at state and local levels is that the most important component of the solution is reducing the amount of surface runoff and nearby seepage that affect the nutrient levels in lakes. Runoff problems can occur from over-fertilization of yards and farm fields. Seepage problems can occur if there are improperly designed septic systems nearby or other activities that can cause organic contaminants to travel through the ground water aquifer into the lake. These runoff and seepage factors not only contribute to algae problems, but also degrade the overall quality of Nebraska’s surface waters, and need to be minimized.

Reflecting Back, and Looking to the Future
DEQ Director Mike Linder had a positive evaluation of the overall organization and responsiveness of those involved at the state and local level.

“The situation over the past year was unusual, and we had to quickly respond to this unexpected new concern,” Linder said. “The response within our agency and elsewhere was exceptional. We received great cooperation from the other state agencies, University Extension, local health agencies, NRDs, and the State of Iowa, just to name a few of the groups we have worked with. The media was also very helpful in getting the message to the public about this situation, and informing the state’s citizens about the precautions that they should take.”

Looking to next year, the state intends to be even better prepared to deal with the issue. Steve Walker, DEQ Water Quality Assessment Section Supervisor, said the group that has been dealing with this issue, as well as other experts in the field, will continue to discuss issues to prepare a strategy for addressing the situation in 2005 and subsequent years.

“This is the first year that we have collected substantial data about toxic algae in Nebraska’s lakes,” Walker said. “We’ll examine this information and data from other states as we look at our long-term plans.”

Walker said DEQ recently applied for and was awarded an EPA grant to conduct a detailed study of the specific conditions that favor blue-green algae blooms in Nebraska lakes. This study will also test the use of weekly overflights – aerial photography using remote sensing technology — to quickly identify lakes with large or expanding masses of blue-green algae.

With this detailed information, the state hopes to be able to identify actions that could help reduce the occurrence of blue-green algae, Walker said. The state will also attempt to develop a predictive early warning system for the public about lakes with potential toxic algae problems before dangerous toxin levels actually occur.

“We plan to target substantial resources into blue-green algae monitoring in the future and we are applying cutting edge technology to better understand the formation of blue-green algae blooms and the release of toxins,” Walker said. “Our goal is to do the best job we can to protect the public and animals against the adverse health effects that can be caused by blue-green algae blooms.”