‘Swimming not recommended’ at Union Grove

SUBMITTED IMAGE — The Iowa Department of Natural Resources issued a ‘Swimming Not Recommended’ warning for three state parks due to excess levels of E-coli in the water. Union Grove near Gladbrook was one of the parks, along with Lake Keomah near Oskaloosa and Pine Lake South Beach near Eldora.

GLADBROOK — Union Grove Lake at Union Grove State Park near Gladbrook was deemed not suitable for swimming due to an excess amount of escherichia coli, commonly known as E-coli, in the water.

The Iowa Department of Natural Resources (DNR) conducted weekly testing on beach water, and found excess amounts of E-coli at Union Grove on May 24, and the warning was issued Friday.

Two other park beaches also had warnings issued due to an excess of E-coli – Lake Keomah near Oskaloosa and Pine Lake South Beach near Eldora. Testing is conducted every week at the 39 state-run beaches.

A high level of E-coli typically is a result of livestock feces in the water. At Union Grove, there was a level of 5,800 Most Probable Number (MPN) per 1,000 milliliters (ml) of water, and was the highest recorded amount.

For comparison, Pine Lake had 390 MPN/1,000ml and Lake Keomah had 460 MPN/1,000ml. The DNR considers a safe level of E-coli as 235 for a single sample.

The no swimming advisory will remain in effect at Union Grove until the amount drops to a safe level. According to the Iowa Environmental Council, Union Grove has received 45 swim advisories due to an excess of E-coli from 2014 to 2022.

The DNR also tests for microcystin released by cyanotoxins, also known as blue-green algae toxins. A safe level of microcystin is 8 micrograms per liter. From 2006 to 2022, Union Grove had no swim advisories issued 17 times for an excess of microcystin.

About E-coli

According to the Mayo Clinic, the majority of E-coli infections occur between June and September. Signs and symptoms of infection begin three to four days after exposure and include:


Stomach cramping

Nausea and vomiting

Anyone can become ill from E-coli, but the people most at risk include children, senior citizens and those with weakened immune systems.

There is no current treatment for E-coli infection, other than rest and fluids. Taking anti-diarrheal medications is not recommended as they slow down the body’s process of getting rid of the infection.


Contact Lana Bradstream at 641-753-6611 ext. 210 or lbradstream@timesrepublican.com.


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