Sierra Club praises DNR for following stricter guidelines for microcystin toxins in Iowa’s lakes - In 2019 DNR resisted implementing updated exposure limits
The Iowa Chapter of the Sierra Club is praising the Department of Natural Resources (DNR) in using the stricter federal guidelines for issuing advisories warning swimmers when microcystin toxins have reached levels that are harmful to human health.[1]
Every summer the hot weather ushers in a series of beach advisories at Iowa’s lakes. One of the reasons for the beach advisory is the presence of microcystin toxins. The beach advisory is a warning that unsafe levels of microcystin exist, levels that are harmful to human health. The toxins are created by bacteria that thrive in waters that are polluted with nutrients (mostly phosphorus) and blue-green algae growth.
On June 6, 2019, the federal Environmental Protection Agency (EPA) released its final recommendations for levels of microcystin toxins that are safe for people who are swimming or participating in primary contact recreational activities on the water. EPA recommends the level of exposure to be 8 micrograms per liter in order to protect swimmers and beach advisories at levels higher than that.[2]
In 2019, the Iowa Department of Natural Resources (DNR) resisted implementing the more restrictive guidelines. They continued to follow recommendations issued by the World Health Organization (20 micrograms per liter).
Sierra Club actively pursued having the more stringent guidelines followed, including working with Representative Art Staed on developing legislation that would require the DNR to use the EPA's guidelines.
How microcystin is created
Blue-green algae looks like a blue-green scum on a lake. The algae can also form thick mats.
Blue-green algae growth is caused by nutrient-rich runoff from farm fields and urban areas entering water bodies during warm weather. The nutrients come from commercial fertilizers and manure. The algae growth attracts a bacteria called Microcystis which produces a toxin called microcystin. The water becomes green and smelly.
Unfortunately one cannot use the appearance and smell of the water to determine if microcystin toxins are present. Sometimes elevated levels of microcystin toxins are present even though there are no signs of a blue-green algae bloom. Although most people would not recreate in smelly water, the toxin can be carried in water droplets, which can expose folks who are not recreating in the water.
Exposure to microcystin toxins is harmful
Exposure to the toxin can cause serious health problems. “The primary concern with microcystin pollution is very young children who play in the shallows and may put their hands in their mouths.”[3] However people of all ages can be harmed by exposure to microcystin. People who come into contact with the water laced with the toxin can develop blisters around the mouth and rashes. Drinking water contaminated with blue-green algae and the related toxins can result in diarrhea, nausea, vomiting, stomach pain, headaches, sore throats, and even liver and kidney damage. Breathing contaminated water droplets can cause respiratory problems such as pneumonia.
Microcystin can also have negative effects on farm animals, pets, and wildlife, including seizures and paralysis.[4]
Blue-green algae and microcystin toxins can affect drinking water
Microcystin toxins may enter into drinking water systems. In August, 2014, national news carried reports that the drinking water in Toledo, Ohio, was unsafe to drink due to the toxin formed by the presence of blue-green algae. For several days, residents of Toledo, Ohio, were forced to drink bottled water and to curtail other uses of tap water.
Iowa cities that rely on surface water sources for drinking water are particularly vulnerable, including Des Moines, Iowa City, and Davenport. Also vulnerable are those cities that rely on water taken from shallow wells, including Cedar Rapids. Luckily Iowa’s drinking water supplies have remained safe.
Current beach advisories are found on DNR webpage
For current information on beach advisories, contact the Department of Natural Resources at 515-725-3434. You can also consult the DNR’s webpage at www.iowadnr.gov/Environmental-Protection/Water-Quality/Water-Monitoring/Beaches
Sierra Club’s Historical Work on Microcystin
Sierra Club has been following the microcystin issue for many years. If you would like to see some of the past work Sierra Club has worked on with respect to microcystin toxins, see:
“Nutrients in Iowa’s Water Bodies Promote Harmful Microcystin Toxin: Iowa DNR resists implementing updated microcystin exposure limits”, July, 2019, https://www.sierraclub.org/iowa/july-2019-newsletter
“April showers bring May flowers and beach advisories: Before the end of May, Iowans were already being warned of beaches with high levels of E. coli and blue-green algae toxins”, June, 2019, https://www.sierraclub.org/iowa/june-2019-newsletter
“Creating a water trustee to ensure Iowa’s waters are fishable and swimmable”, January 20, 2019, https://www.sierraclub.org/iowa/blog/2019/01/creating-water-trustee-ensure-iowa-s-waters-are-fishable-and-swimmable
“It's Time for a Moratorium on confined animal feeding operations (CAFOs)” April, 2020, https://www.sierraclub.org/iowa/april-2020-newsletter
“Topsoil a Dirty Subject -- DNR Will Not Provide Cost-Benefit Analysis to Legislature”, November, 2015, https://www.sierraclub.org/iowa/November2015E-Newsletter
“Blue-green Algae Affects Iowa’s Waters”, July 16, 2015, https://www.sierraclub.org/iowa/blue-green-algae
[1] Erin Jordan, “Iowa gets tougher on toxins at its beaches”, Cedar Rapids Gazette, June 6, 2020
[2] “Recommended Human Health Recreational Ambient Water Quality Criteria or Swimming Advisories for Microcystins and Cylindrospermopsin”, Environmental Protection Agency, June 6, 2019
[3] Erin Jordan, “Warning of toxins is first for Lake Macbride, Researcher describes ‘pea soup’ as far as the eye can see’ at Solon site”, Cedar Rapids Gazette, June 30, 2019
[4] Jane J. Lee, “Driven by Climate Change, Algae Blooms Behind Ohio Water Scare Are New Normal,” National Geographic, August 4, 2014