Iowa will post swimming beach warnings for a much lower level of algae toxins this season after state environmental officials belatedly agreed to tighten limits under federal pressure.
Alicia Vasto of the nonprofit Iowa Environmental Council said that should mean safer outings.
“The (new limit) is more protective. It helps people make their own decision on how safe they feel getting into the water and understanding the risks,” said Vasto, the council’s water policy and advocacy specialist.
Blue-green algae, which are common in Iowa, under certain conditions emit four types of toxins. The one that is measured most widely is microcystin, which can cause rashes, diarrhea, pneumonia, and in rare cases, death. The other three toxins cause a range of illnesses, including liver damage and neurological problems.
Iowa has in recent years posted advisories at state-park beaches based on levels of the toxin, and separately on levels of fecal bacteria.
Advisories for high microcystin levels have risen in recent years, while those related to fecal bacteria have fallen. Some lakes have had more frequent problems.
DNR noted that the tighter limit will mean more advisories, but that won’t necessarily mean a big change in water quality. Vasto said the environmental council will be watching to see if the DNR’s statement was warranted or an effort to downplay the situation.
“Our organization will be looking really hard at specifically the difference in the number of advisories at different levels to see if that is a rational statement to make or not,” Vasto said. We don’t want to exaggerate what the water quality problem is. But it is not necessarily terrific.”
DNR has followed recommendations of the World Health Organization for beach advisories since 2006, spokesman Alex Murphy said. When the U.S. Environmental Protection Agency recommended a standard of 4 micrograms per liter in 2016, DNR questioned the methodology.
When EPA raised the proposed limit to 8 micrograms after states protested, DNR decided to adopt the standards with these caveats:
- It only applies to beach advisories, not to other water quality rules.
- The state standard may change based on newer research or updated information on the calculations used.
- Higher numbers of advisories are expected, but don’t necessarily mean worse water.
Mary Skopec, executive director of the Iowa Lakeside Laboratory along West Okoboji Lake, said the new DNR standard is appropriate, though she would have supported 4 micrograms, too.
“One of the things that Iowa has struggled with is there is no magic to any of these numbers,” Skopec said. Samples are often taken on Monday or Tuesday and results aren’t confirmed until Friday. That means the water could be better, worse, or the same by your weekend outing, Skopec said.
“It’s a guidepost, not a speed limit,” she added.
But particularly with the algae toxins — there are four major groups — the health threat is more severe, Skopec said. Some can even cause neurological and liver damage. If a test finds microcystin early in the week, there is a good chance it will still be there by the weekend.
“We are seeing an upward trend in Iowa and in other states,” Skopec said. “We are seeing a signal and need to be careful with the advisories. Microcystin can be persistent.”
The state started checking for microcystin in 2006, when 23 beach advisories were posted for the toxin. That fell off to one in 2009 before rising consistently and hitting a high of 37 in 2016. Last year, there were 21 advisories under the old standards of 20 micrograms per liter.
Despite the drop in bacteria-related advisories the past few years, Skopec said it’s hard to see an overall improvement in the beaches since the state’s weekly monitoring started in 1999, and now includes 39 beaches. “I haven’t seen any indication of a significant trend,” said Skopec, who used to oversee the beach monitoring program at DNR.
Beaches with the most advisories
The Iowa Environmental Council has a web page showing the number of advisories at each beach over the years.
These have had the most beach advisories:
Green Valley Lake, 47
Black Hawk Lake, 21
Lake of Three Fires, 15
Union Grove Lake, 12
Rock Creek Lake, 11
Viking Lake, 10
E. coli (fecal bacteria) (2014-2019)
Backbone Lake, 80
Beeds Lake, 53
McIntosh Woods Beach, Clear Lake, 47
Lower Pine Lake, 35
Emerson Bay, West Okoboji Lake, 31