For the last few years, the U.S. Army Corps of Engineers (USACE) and the Kentucky Division of Water (DOW) have monitored the state’s waters for harmful algal blooms, commonly known as HABs.
Algal blooms, and the algae that form them, occur naturally in the water. Certain factors, such as warm water temperatures, low turbulence and elevated nutrients like phosphorus and nitrogen, promote the growth of HABs. Nutrients can come from many sources including crops, pastures, and urban and industrial areas. HABs are likely to occur when there are warm water temperatures, excess nutrients and low turbidity in the lakes.
What do HABs look like? The typical green algae, which is not harmful to humans or animals, comes in many forms and looks like underwater moss, stringy mats or floating scum. HABs, or cyanobacteria, are blue-green in color and appear as slicks of opaque, bright-green paint. Upon closer inspection, they often reveal a grainy, sawdust-like appearance of individual colonies of bacteria. The algae can also appear as red or brown.
Some cyanobacteria produce toxins that can be hazardous to animals and humans. Symptoms of exposure to HABs may include gastrointestinal symptoms such as stomach pain, nausea, vomiting and diarrhea; skin and eye irritation; and/ or throat irritation or breathing difficulties.
While most Kentucky lakes and rivers that contain algal blooms remain open to recreational use, visitors should be aware of the possibility of potential health impacts associated with water contact and take precautions. Some lakes and rivers are posted for “no swimming” however, contact with the water can still occur through recreation activities such as fishing. The following guidelines are recommended to reduce exposure to HABs:
- Avoid direct contact with affected water, including activities such as swimming, wading, fishing, paddling, diving and water skiing. Avoid contact with water that has unusual color or where blue-green algae has been identified, even if the water appears to be clear.
- People who are prone to respiratory allergies or asthma should avoid areas with HABs. Children may be particularly sensitive.
- Skin exposed to water containing blue-green algae should be washed off with fresh water. In some cases, skin irritation will appear after prolonged exposure. If symptoms persist, consult your local health care provider.
- Fish fillets (not organs) may be consumed after the fillets have been rinsed in clean, non lake water. Wash your hands or any parts of your body that have come into contact with the fish.
- Pets and livestock should be prevented from making contact with HAB-infested waters.
Last summer, the DOW confirmed the presence of HAB toxin levels exceeding recommended safety thresholds on the Ohio River and several lakes in Kentucky.
If HABs are identified in any lake or river, an advisory will be issued to the public. An advisory is intended to educate potential users about the water so that they may make informed decisions.
Public water systems depending on lakes for their raw water source should monitor for the presence of HABs and adjust treatment of the water accordingly. Algal blooms are effectively addressed through water treatment techniques, producing water that is safe to drink.
The proper management of nutrients from stormwater runoff in watersheds and the proper treatment of these nutrients in wastewater play a key role in managing algal blooms of all kinds. The DOW, along with other federal and state partners and stakeholder groups, is developing a nutrient reduction strategy to address nutrient pollution problems in Kentucky.
For updates on water levels and HABs at USACE lakes visit http:// http://www.lrl.usace.army.mil/Missions/ CivilWorks/WaterInformation/HABs.aspx.
For safe water recreation visit http://www.who.int/water_ sanitation_health/bathing/srwe1/en/. For additional information regarding HABs and public water systems, contact Eric.firstname.lastname@example.org.