Swimming is a popular summer pasttime in southeast Iowa, but with the added rainfall and sunlight this year, lakes and beaches are seeing heightened levels of microcystins and E. coli in the water.
As of July 18, swimming at Lake Darling in Washington County was not recommended by the Iowa Department of Natural Resources (DNR) due to high levels of cyanobacteria toxins or bacteria commonly found in lakes. That recommendation has since expired and as of the afternoon of Friday, Aug. 9, the lake was deemed OK for swimming once again.
For similar reasons, central Iowa lakes, such as both Lake Ahquabi and Nine Eagles Beach, were under similar warnings due to heightened levels of E. coli. As of the afternoon of Friday, Aug. 9, both were deemed OK for swimming.
As part of their beach program, the DNR checks each beach and lake once a week to keep swimmers and boaters safe. For instance, Lake Darling had and may still have bacteria that could potentially harm swimmers.
“That is due to a cyanobacteria that acts more like an alga,” Daniel Kendall of the Iowa DNR said. “They can get energy from sunlight as algae and plants do, and some of those cyanotoxins can produce toxins and we have an adviser threshold and Lake Darling was exceeding that threshold.”
These bacteria can arrive at a beach or lakefront in many pathways. The first involves animals carrying these bacteria into the body of water. The second is the same concept, but is created by humans and the third is when a septic system is poorly constructed and develops a leak that is located near the water.
“Bacteria comes in the gut of warm-blooded living organisms,” Kendall said.
When these viruses and other E. Colis make their way to a body of water and are acquired by a swimmer, these people will most likely endure symptoms that resemble those of a germ-flu carrier — stomach aches, throwing up, a running fever, among other things.
The Iowa DNR website suggests that people avoid swimming after downpours when the water is cloudy.
“Young children swimming at the beach can leak fecal bacteria and associated pathogens from their diapers, so change your child’s diapers often and visit bathrooms frequently,” Iowa DNR wrote. “If you or your child has diarrhea, please stay out of the water because you may contaminate the water with fecal material.“
The Iowa DNR encourages people with any questions or possible concerns to email them at: firstname.lastname@example.org
According to a report from The Gazette, Lake Macbride was under a similar do not swim advisory on June 21, the first it has ever had. The advisory expired once the microcystins in the water were killed off by the sun, but the E. coli bacterial levels were recorded as being higher than normal.
According to the article, Lake Macbride is one of 39 state parks that receives weekly water monitoring. On June 18, the water test showed the microcystin levels were at 22.26 micrograms per liter of water. The standard to avoid an advisory is 20 micrograms-per-liter, according to the DNR. The article also stated Lake Macbride was under an E. coli advisory 12 of 15 weeks last summer. As of Friday, Aug. 9, the lake was deemed OK for swimming according to the Iowa DNR, as the microcystins were recorded on Aug. 5, as being less than 0.75.
McIntosh Woods State Park in north-central Iowa was also issued a swimming advisory due to E. coli contamination, according to KCCI. The Mason City Globe Gazette reported a sample taken at the lake near Ventura exceeded the safe amount of bacteria found in fecal matter. As of Friday, Aug. 9, the lake was still under a “swimming not recommended” advisory by the Iowa DNR.
The article said surface runoff after a heavy rain was the possible culprit and that sunlight would eventually destroy the bacteria and improve the water quality.
The Iowa DNR has an interactive map where beaches at state parks are monitored for water quality and are updated as tests are performed. As of Friday, Aug. 9, seven beaches in Iowa were under “swimming not recommended” advisories: Emerson Bay Beach, Milford; McIntosh Woods State Park, Ventura; Backbone Beach, Dundee; Union Grove Beach, Gladbrook; Green Valley Beach, Creston; Lake of Three Fires Beach, Bedford; Honey Creek Beach, Moravia.
The map can be found online at: www.iowadnr.gov/Environmental-Protection/Water-Quality/Water-Monitoring/Beaches.
- Carter Melrose contributed to this story.