Jenna Ladd | September 9, 2016
The Iowa Department of Natural Resources (DNR) monitors the water at state beaches each season from Memorial Day through Labor Day. DNR issued six beach advisories this week for a total of 37 microcystin warnings this year, surpassing last year’s record of 34, just as DNR officials predicted earlier in the season.
Microcystin is considered toxic to humans when levels are at or above 20 micrograms per liter (ug/L), according to the World Health Organization (WHO). Swimming in water that has harmful levels of microcystin in it can cause breathing problems, upset stomach, skin reactions, and liver damage. If the water is inhaled, it has been known to cause cause runny eyes and nose, cough, sore throat, chest pain, asthma-like symptoms, or allergic reactions. Contaminated bodies of water can be especially harmful to pets and children, who are more likely to ingest water.
In total Iowa DNR has issued 185 microcystin beach advisories since 2006, and two-thirds (117) have been in the most recent four years. The blue-green blooms that produce microcystin feed on nutrients like phosphorus and nitrogen that seep into waterways from pollution sources like agricultural fertilizers, livestock waste, septic systems, and urban runoff. Blue-green algae toxins do not only pose a threat to beachgoers. Last month, Des Moines Water Works detected microcystin in treated municipal drinking water.
While DNR monitors 39 State Park beaches across Iowa for these toxins, many public and private beaches are not monitored. As the total number of beach closures rises each year, Ann Robinson, agricultural specialist at the Iowa Environmental Council said, “This is a wake-up call that more needs to be done to reduce the nutrient pollution coming from the farms, city lawns and urban and industrial wastewater plants that are feeding the algae. If we don’t take action on the scale needed, unprecedented numbers of beach warnings will become our new normal.”
More information about identifying harmful blue-green algae blooms and a chart that outlines dangerous levels of microcystin in Iowa’ lakes dating back to 2006 can be found at the Iowa Environmental Council’s website.