The Iowa Department of Natural Resources (DNR) decided to follow stricter standards this summer for the amount of toxins found in the water at public beaches.
Microcystin is a toxin produced by cyanobacteria in algae blooms in Iowa’s lakes. It poses health threats to humans and animals that swim at beaches with high levels of the toxin and can cause abdominal pain, blistering, pneumonia and vomiting if ingested. Dogs have also died from being exposed to it, according to an Iowa Environmental Council news release.
In 2006, Iowa DNR began using a threshold of 20 micrograms per liter to issue beach advisories. However, they decided to lower it to 8 micrograms per litre this year after the Environmental Protection Agency (EPA) recommended it.
The DNR currently monitors only a small percentage of Iowa’s recreational beaches, but they were able to issue a number of advisories and temporarily close beaches on Lake Macbride, Spirit Lake and Lake Rathbun last year when microcystin levels exceeded the threshold. The number of advisories issued this year is likely to be much higher than past years under the new guidelines.
Iowa farmers are implementing practices to increase sustainability and reduce environmental threats to public health, including crop rotation, use of cover crops, eliminating pesticides, and using alternatives to chemical weeding. One group called Practical Farmers of Iowa organized a series of educational field days over the summer, providing opportunities across the state for farmers to share and discuss these practices. One of the environmental threats in the state comes from nutrient runoff from agricultural fertilizers, which recently have contributed to the growth of toxic microcystins in some Iowa bodies of water, making sustainable farming not just an environmental issue, but a public health concern as well.
Research published last month from Iowa State University scientists found that the widely-used practice of crop rotation helps to reduce pollution, but also depletes organic matter in soil over time. Rotating between corn and soybeans requires less nitrogen fertilizer than continuous corn production, as soybeans leave behind a nitrogen-rich residue in the soil. This allows farmers to save on costs and reduce nitrogen runoff into freshwater lakes and streams. However the abundance of nitrogen contributes to the growth of microbes which, on years when corn is planted, consume nutrients needed for corn production, depleting this organic material in the long run.
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.
Warm July temperatures coupled with excess phosphorus that often runs off of farm fields into lakes and waterways creates the ideal breeding ground for blue-green algae. These conditions lead to the creation of microcystin toxins which can cause skin rashes and asthma-like symptoms for humans and potential fatalities for dogs, livestock, and other animals.
Earlier this month, Florida governor Rick Scott issued a state of emergency because of harmful algal blooms on bodies of water in the Sunshine State. NASA satellites captured images of algal blooms on Lake Okeechobee in May.
Check out the Iowa DNR website for reports of blue-green algae and other bacteria at state-owned beaches. Mary Skopec with the Iowa DNR advises swimmers, boaters, others to be cautious of water that is green in color or scummy in texture.