Harmful Algal Blooms

Pond surrounded by grass

This toolkit, offered by Small Business Environmental Assistance Program (SBEAP), is intended for privately-held water features in urban and suburban areas, especially those managed by homeowners associations (HOAs). Managers of other private water bodies, such as those found on golf courses, campgrounds, clubs and private estates, may also benefit from this web resource. If the private water body of concern is agricultural in nature, then contact your local extension office or the K-State Veterinary Diagnostic Lab. To report a bloom observed in a public waterbody managed by a municipal, state, or federal entity, or that serves as a public water supply, visit the Kansas Department of Health and Environment (KDHE) Harmful Algal Blooms website to submit a report online or by phone. The KDHE HABs Response Program addresses reports of HABs on publicly owned and managed waterbodies only.

A private waterbody, such as a pond or lake, can raise property values and be an aesthetically pleasing part of a neighborhood. All private property owners in association-governed communities are expected to maintain and manage their stormwater infrastructure and be accountable for all processes that occur in the waterbody, with relatively little assistance or oversight from local government. One possible result of poor maintenance is the formation of thick coats of green or brown algae, or worse yet, blue-green algae. Such blooms can cover an entire pond, kill fish, sicken pets and people, and may generate noxious odors in the vicinity. Lack of maintenance of these water bodies, therefore, comes with a disadvantage.

What Are HABs?

Harmful algal blooms, or HABs, refer to a dense growth of algae with the potential for creating toxins or other nuisance compounds. In fresh water, most HABs are composed of blue-green algae, also known as cyanobacteria. Although blue-green algae are a natural part of water-based ecosystems, they become a problem when nutrients (phosphorus and nitrogen) are present in concentrations above what would naturally occur. Certain cyanobacteria can produce harmful toxins, such as microcystins, nodularin, or anatoxin. Human or animal exposure to or ingestion of these toxins can cause skin rashes, liver and kidney toxicity, nervous system problems, respiratory complications, and even death. Some studies have even suggested that chronic exposure to cyanobacteria may be linked to degenerative diseases such as ALS, Alzheimer’s and Parkinson’s.

Many factors affect the growth and bloom of harmful algae in lakes and other waterbodies, but weather conditions such as temperature, sunlight, and water clarity are primary contributing factors. Combined with excess nutrients, these factors create conditions favorable for overgrowth of blue-green algae and development of HABs. Blooms usually happen when the right combination of these factors are met, commonly in a hot drought period in summer or early fall, after spring rains have carried fertilizers into lakes and ponds, and when water clarity is relatively high.

Health Effects on Humans and Animals

The biggest risk to health comes from contact with or ingestion of the toxins produced by the blue-green algae. This can occur during activities that bring an individual into full-body contact with the water or from inhaling spray cast up from the water's surface. Children and pets are most at risk while engaging in recreation in the water and can become ill after being exposed. Adults with compromised immune systems are also more susceptible to illness from exposure. The most common complaints after recreational exposure include vomiting, diarrhea, skin rashes, eye irritation and respiratory symptoms. Exposure to algal toxins can cause illness or possibly even death. There are no known antidotes to cyanobacterial toxins. If you suspect a person has suffered an adverse health event from HAB exposure, seek medical treatment immediately, then report to KDHE Epidemiology by completing an online Human Algae-Related Illness Form, calling KDHE’s Epidemiology Hotline at 877-427-7317, or emailing KDHE.EpiHotline@ks.gov.

Pets may ingest algae while cleaning their fur or even find the dried algae along a shoreline attractive to eat. The toxins can affect the liver, nervous system, skin and other organs. If you suspect an animal has suffered poisoning from a bloom, watch for symptoms that include vomiting, diarrhea, weakness, staggering, difficulty in breathing, and convulsions, contact a veterinarian immediately. If there is an animal health incident, please consult K-State Veterinary Diagnostic Lab Client Care at 866-512-5650 and fill out KDHE’s online Animal Algae-Related Illness Form. You may be asked to collect a chilled sample of the water that is suspected; if so, please do this with appropriate protection and do not store the sample near food/drinks. 

For general questions not related to a specific incident, call SBEAP’s hotline at 800-578-8898.

Note that the Human and Animal Illness forms are reported to KDHE’s Bureau of Epidemiology and Public Health Informatics, which tracks data from private as well as public waterbodies.

Identifying and Sampling

While some HABs will have a distinctive look, it is impossible to differentiate between toxic and non-toxic types just by looking at them. Some blooms have an unpleasant odor which can be compounded by a combination of stagnant water, dying blooms and decomposing organic debris. Blue-green algae are often concentrated on or near the water surface with visible soup-like scums and/or the water appears bright green or blue-green, or even occasionally red or pink. View examples of blue-green algae in Kansas here. Anyone can perform a stick test or a jar test to confirm whether a particular algae sample is likely to be blue-green or another type. Use this instruction page to perform jar and stick tests. Otherwise, private waterbody owners who suspect a HAB may wish to have their water tested by a commercial laboratory.

Laboratory Screening

This list can help locate HAB screening lab resources. Publication of this information does not constitute an endorsement or recommendation by the KDHE or SBEAP for these companies. This list includes consultants and laboratories known to provide sampling and analytical services related to cyanobacteria (blue-green algae) in freshwater systems. Services may include algal identification and enumeration, testing water samples for cyanotoxins, and related services. This list will be revised as new vendors are made known to us. Not all entities on the list provide all services, and some may contract some of them out. Please be specific as to your needs and expectations. KDHE does not certify or license algal identification or toxin analysis laboratories. Note that sample collection, handling, and shipping often require particular containers or procedures. Some require special preservatives or kits. Be sure to contact the laboratory as soon as possible if you wish to send samples for analysis.

Downloadable Resources

SBEAP provides technical assistance, support, and problem troubleshooting, and serves as an informational forum to support HOA community managers to help maintain their ponds in as healthy and HAB-free condition as possible.

Preventing HABs

Prevention is the best option for protecting human and animal health during a bloom. Keep in mind that excess nutrients within the system are the primary cause of HABs. The best long-term approach to address HABs is to implement practices to prevent these nutrients (phosphorus and nitrogen) from entering the waterbody during wet weather and runoff conditions and to prevent direct introduction of nutrients from such sources as resident populations of Canada geese or excessive feeding of fish.

  • Physical intervention: Phosphorus, one of the nutrients that promotes algal growth, can bind to sediments on the lake bottom and remain available for many years. Thus one technique to remove or prevent algae outbreaks in HOA ponds may be to have the pond dredged.
     
  • Chemical intervention: Several chemical additives available on the market such as alum or phoslock which are phosphorus-binding products, and may help control the bloom.
     
  • Short-term interventions, such as the application of algaecides, may halt an active bloom.  Peroxide-based algaecides dissipate quickly with no residue, but many commercially available algaecide products can leave residues harmful to aquatic life.  Many algaecides, like other chemicals, have strict guidelines for application and may even require permits. Note, too, many algae release toxins from their cells when they die, so application of some types of algaecides, especially during an active bloom, could actually release toxins. Also, KDHE does not endorse or recommend any particular in-lake mitigation option, but the use of products containing copper or ingredients that are harmful to aquatic life is discouraged.
     
  • Mechanical intervention: Devices that aerate or help mix the water may be effective in controlling development of blooms.
     
  • Biological intervention:  One approach to increase aquatic plant diversity in the pond is to add appropriate shoreline plantings or floating gardens (preferably with plants native to Kansas), which can also absorb nutrients at the water's edge and provide a buffer to help reduce runoff from entering the waterbody after heavy rains. Some studies have shown partially submerged, fungicide-free barley straw, applied in springtime, to be an effective and inexpensive way to prevent bloom development. All options only seem to work if proactive action is taken to control the bloom. 

As most waterbodies are dynamic in nature, it is recommended that owners and managers of private water bodies consult a professional to determine an effective course of action. It is also recommended any treatments be accompanied by baseline and follow-up monitoring. However, keep in mind, not every solution fits every situation!

Dos and Don’ts

The only known way to prevent harmful algae blooms from occurring is to prevent the conditions that cause them. Being reactive when a bloom occurs is not enough – it might solve the problem temporarily, but unless you fix the underlying causes, your lake or pond may be very expensive to maintain. To help limit the growth of HABs in community waterbodies, SBEAP and KDHE recommend the following sustainable measures to homeowners’ associations:

Do...   
...conduct a soil test before fertilizing your lawn.
...use fertilizers sparingly and appropriately to limit nitrogen and phosphorus-rich runoff.
...create a buffer area around the waterbody with native plants to absorb nutrients from the runoff.    
...pick up and appropriately dispose of pet waste.  
...regularly test the water quality.    

Don’t...
...over-fertilize your lawn, and don’t apply before anticipated rainfall.
...dispose of grass clippings and other organic waste near the waterbody.
...keep the grass too short, attracting geese and other waterfowl.
...feed birds or overfeed fish in the waterbody.

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