The Iowa Department of Natural Resources doesn’t plan to follow new federal recommendations for beach water quality that could lead to more public warnings.
The U.S. Environmental Protection Agency recommended May 22 that states issue advisories against swimming at public beaches when microcystins, a toxin released by harmful algal blooms, are at levels of more than 8 micrograms per liter of water.
The Iowa DNR posts advisories when microcystins are more than 20 micrograms per liter — a standard set by the World Health Organization — and officials say the lower standard would triple the number of state park beach advisories without proof the water is any safer for recreation.
“The group does not agree with the formula and science used to develop the 8 micrograms per liter for cyanotoxins microcystins standard,” said Iowa DNR spokesman Alex Murphy.
The department conducts weekly water tests at 39 state park beaches from Memorial Day weekend through Labor Day, checking for E. coli bacteria and microcystins. E. coli is an indicator for fecal material, which can carry parasites or other pathogens that can sicken swimmers. Microcystins, generated when blue-green algae die, can cause gastroenteritis, skin irritation, liver damage and nerve damage.
If the levels are too high, technicians post swim advisories at the beaches and online. The state issued 111 advisories last summer, with only six of those for microcystins. There were 37 microcystin warnings in 2016.
The Iowa DNR says if technicians had used the EPA’s lower threshold for microcystins last year, it would have had 17 swim warnings instead of six.
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Some of the additional advisories would have been at state parks, including Green Valley, Viking Lake and Lake of Three Fires, southwestern Iowa tracts that are perennially dealing with harmful algal blooms.
But Eastern Iowa’s Lake Macbride, which had numerous E. coli warnings last summer, also would have had a microcystin advisory if the state had been using the EPA’s recommended standard, the department reported.
Nationwide, reports of algal blooms have increased since 2010, the Environmental Working Group reported earlier this month, with climate change exacerbating fertilizer runoff.
Mary Skopec, former Iowa DNR beach monitoring coordinator who now leads the Iowa Lakeside Laboratory on West Lake Okoboji, said the state should consider switching to the EPA’s lower threshold for microcystins.
“That level of 8 is really protecting the most vulnerable — children who spend time in that shallow water where those scums come up on shore,” Skopec said. “Kids put their hands in their mouths a lot.”
Iowa had no confirmed cases of microcystin poisoning in 2018, but there have been cases in other states in recent years.
A 2015 article in the journal Toxins said there were 34 reports of human and animal illnesses from harmful algal blooms in Kansas in 2011, with the cases including five dog deaths and hospitalization of two humans.
The Iowa DNR said the EPA used a “flawed” approach by setting the standard based on chronic exposure to the toxins, not the occasional exposure of going to a beach. This is according to a 2017 letter the department sent to the EPA opposing a previous recommended cap of just 4 micrograms per liter.
The EPA relaxed that earlier standard after feedback from states.
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Iowa DNR officials said they will further review the EPA’s new recommendations, but Murphy said Iowa already has more oversight of beach water quality than many states that don’t test for microcystins.
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