by Kirsten Delamarter
The final stretch of intense summer heat may be uncomfortable for Kentuckians, but there’s one thing that thrives during this period: algae.
During the past few weeks, the Kentucky Division of Water has been receiving more reports of potentially harmful algal blooms across the Commonwealth. That’s in large part because of the warm water temperatures but also a lack of rain, which causes otherwise flowing bodies of water to slow, said Water Quality Branch manager Melanie Arnold.
As of Sept. 23, there had been no recreational public health warnings issued in Kentucky because of harmful algal blooms, or HABs. But over the weekend, the Division of Water issued a caution, as screening-level data indicated cyanotoxin concentrations that while generally below the DOW’s advisory threshold, exceeded the threshold with one data point.
The DOW encouraged caution when it comes to recreating in the Ohio River near Northern Kentucky and Cincinnati, based on visual observations of harmful algae in the area, cyanobacteria cell counts and cyanotoxin screening data.
Here are five things you should know about algae, cyanobacteria and HABs.
1) Not all algae is harmful.
Algae naturally occur in all of the state’s fresh water systems and play an important role in the aquatic ecosystem. However, a number of factors can cause algae to grow excessively in a body of water, including warmer temperatures, plentiful sunlight and excess nutrients.
When these conditions occur, algae thrive — as do cyanobacteria, a photosynthetic aquatic bacteria commonly referred to as blue-green algae (although cyanobacteria are not technically algae).
Cyanobacteria can give the water an unsettling appearance, sometimes like spilled paint or pea soup. They can also produce toxins that present health risks to humans and animals and may result in treatment challenges for drinking water systems.
“The water looks uninviting,” Arnold said. “The Division discourages people from recreating in water with these kinds of surface scums.”
2) Harmful algal blooms can affect the health of humans and animals.
Although not all cyanobacteria produce toxins and some only produce toxins under certain conditions, cyanotoxins can affect the liver, nervous system or skin of animals and humans.
This is why when a harmful bloom has been reported — and particularly if tests show concentrations of toxins above the state’s advisory threshold — it’s wise to avoid coming into contact with affected water bodies and to take similar precautions for pets and livestock.
Click here to read more about the Division of Water’s recommended precautions.
3) The Division of Water monitors bodies of water using remote sensing and takes action when a potential HAB is reported.
The Water Quality Branch uses remote sensing — satellites that take images of Kentucky’s larger water bodies — to detect changes in color or chlorophyll levels, but it also relies on reports from the public to detect possible HABs.
When the Division of Water receives a report of a potential HAB, it notifies its partner agencies, including any drinking water facilities using that body of water.
“They tend to know because there’s often taste and odor issues associated with increased algae,” Arnold said.
Then, DOW staff or other state or federal agency partners will visit the body of water and collect toxin samples that are then analyzed in the state lab to determine whether cyanotoxins are present at levels above the state’s warning threshold.
If so, an advisory is issued jointly by the Department for Environmental Protection and the Department for Public Health, Arnold said.
Click here to learn more about the Volunteer Lakes Monitoring Program, which trains citizen scientists to aid in the monitoring efforts of Kentucky’s streams, rivers and lakes.
4) Check out the HAB Viewer to see whether a body of water is affected.
The Division of Water maintains the Harmful Algal Bloom (HAB) Viewer, which allows the public to see where HABs have been reported and, once testing has occurred, the findings of the tests.
Click here to access the HAB Viewer.
5) Mindful fertilizer use can help prevent HABs.
Arnold said that in addition to weather conditions, an excessive amount of nutrients in the water can contribute to nuisance blooms. To help prevent HABs, “people can be mindful of their fertilizer use,” Arnold said.
The Division encourages users of fertilizers to abide by the 4Rs: the right fertilizer source at the right rate, at the right time and in the right place.
Learn more about the 4Rs here.