Substandard Living: Iowans Deserve a Microcystin Standard

In Iowa, regulatory discussions often are muddled by a debate on optics. These past months have proved this to be true in exchanges between the Iowa Department of Natural Resources (DNR) and the Environmental Protection Agency (EPA). The EPA recently released new recommendations regarding microcystin in recreational waters, with the goal of helping local and state officials to make informed decisions in protecting the public. 

Microcystin, a toxic byproduct of blue-green algae, can cause significant illness in humans, pets, and livestock. The EPA’s recommendation is to issue a swim advisory when microcystin reaches or exceeds eight micrograms per liter. The agency also states this value may be considered for states adopting a water quality standard for microcystin as well. The EPA’s recommendation is reflective of the latest scientific knowledge and provides flexible guidance on how states might implement this guideline. However, it’s up to states to adopt limits and enforce standards.

Iowa does not currently have an ambient water quality standard for microcystin. The DNR reaffirmed this position following the EPA recommendations being released, citing their existing twenty micrograms per liter swim advisory threshold and questioning the methodology used to derive the new EPA recommendations. 

Advisories as a Public Health Measure

From a public health perspective, the DNR‘s refusal to set a standard and rely on its current advisory threshold is concerning, especially when framed in the context of the precautionary principle. This ideal is embedded into science-based policy making. The basic tenet is to use caution in the face of uncertainty and potential risk.

In its recommendations, the EPA cites studies regarding long-term exposure to microcystin that lead to liver and kidney issues as one indicator of health risk. Further, the EPA’s guidelines were based on its Exposure Factors Handbook, which details risks surrounding incidental ingestion of water during recreation, especially for children.

During the comment period for the EPA release, the IDNR submitted comments saying this consideration isn’t relevant to recreational use, a response which the EPA rejected due to studies documenting the amount of water children swallow while swimming. The IDNR also stated that increasing the threshold would ultimately be burdensome to the agency and overprotective.

Despite the IDNR’s claim that increasing the threshold would be burdensome, the amount of work wouldn’t actually change. The only change is the threshold used to issue a swim advisory. The public will still be able to decide whether to swim, but they will have more information. The reason the DNR has a microcystin monitoring program is to assess risk and empower the public to avoid potential negative health outcomes, especially for the most vulnerable populations - particularly children.

Beach advisories serve as an indicator to the public and a tool for risk assessment; however, the DNR’s current use of the process doesn’t support giving the public the most information possible. If the DNR accepted the EPA's recommendation, the agency would have issued a swim advisory for Lake Darling this week, which is measuring microcystin at 11.8 micrograms per liter.

“The risk of negative outcomes by not accepting the new advisory level is higher than the burden placed on DNR staff if it is accepted. The DNR should adopt the standard that is most protective of public health,” says IEC’s Water Program Director, Ingrid Gronstal Anderson.

We urge the IDNR to reconsider its stance on the microcystin swim advisory recommendation.

Danny O'Halloran
IEC Communications Intern

1. beach advisories
2. clean water
3. dnr
4. harmful algal blooms
5. microcystin
6. public health
7. toxic algae
8. water quality