Nicole Welle | September 17, 2020
The Iowa DNR issued advisories for over half of state park beaches this summer due to unsafe levels of E. Coli bacteria or microcystins in the water.
DNR conducted weekly tests Memorial Day through Labor day, and 39 state park beaches had at least one week during the summer where toxin levels were high enough to trigger a warning. They reported a total of 118 advisories over the summer, an increase from the 79 advisories issued in 2019, according to a Cedar Rapids Gazette article.
E. Coli, which indicates the presence of feces in the water, was responsible for most of the warnings. However, elevated levels of microcystins, which caused 12 advisories, can lead to a range of health problems in people exposed to them. These include gastroenteritis, allergic reactions and potentially life-threatening liver damage. Microcystins are produced by certain types of freshwater blue-green algae.
Studies have shown that much of the bacteria and toxins causing the warnings come from manure runoff and contaminates from nearby fields. Sandy beaches also tend to have higher levels of bacteria from manure from geese and other animals. Higher levels of toxic algae blooms, however, can have a variety of causes. Weather, temperature, nutrient availability and other environmental stressors are all factors, according to Dan Kendall, and environmental specialist in charge of the beach monitoring program.
The DNR’s Lake Restoration Program has plans to begin reducing bacteria in some of Iowa’s lakes that have been most heavily affected and continue testing each summer to monitor toxin levels.