December 1, 2015

Reacting to What’s Flowing Down the River

Cyanobacteria, commonly referred to as blue-green algae, are a serious problem in surface water sources in the United States, including Iowa.  Cyanobacteria grow and multiply quickly where there are high nutrients (nitrogen and phosphorus) in warm, calm waters.  Blooms create blue to green murky water, visible surface scum and a foul odor. The blooms can spread across the water but tend to accumulate in shoreline areas.

IMG_5714{Cyanobacteria bloom at Big Creek State Park. Photo courtesy of Iowa Environmental Council

While algae blooms are a nuisance, certain forms of blue-green algae can also produce toxins that can make humans and animals sick.  The Iowa Department of Natural Resources (DNR) monitors state park beaches weekly in the summer for the toxin microcystin that is produced by some forms of blue-green algae common in Iowa. Warnings are posted when microcystin exceeds 20 parts per billion (ppb), a guideline established by the World Health Organization for recreational waters. Contact with water with more than 20 ppb of microcystin represents a risk of cyanotoxin associated illnesses including breathing problems, stomach upset, skin reactions, and even liver damage. Inhaling water droplets containing microcystin can cause runny eyes and nose, cough and sore throat, chest pain, asthma-like symptoms or allergic reactions. Pets and other animals that swim or drink the water can be exposed to deadly levels of microcystin.  This year has been favorable for cyanobacterial blooms, with high nutrients and warm waters. Iowa Department of Natural Resources posted a record 34 warnings at state park beaches with high levels of microcystin.

It is important to note that while DNR monitors state park beaches for this toxin, the problem is not isolated to these lakes. Many other public and private beaches not monitored by DNR are also susceptible to blue-green algae blooms.

Cyanobacteria are also known for causing taste and odor problems in drinking water for utilities that use surface water.  When cyanobacteria counts rise, there is greater potential for the presence of cyanotoxins, which raise health concerns related to the liver, nervous system and gastrointestinal system.  Last year, the City of Toledo, Ohio, issued a “do not drink” order. The municipal ban left approximately 500,000 Toledo and Michigan residents without drinking water for three days, which was contaminated by a toxin produced by an algae bloom in Lake Erie.

Currently there is not a federal standard for blue-green algae or their toxins in drinking water; however, a growing number of states are introducing their own guidelines and the U.S. Environmental Protection Agency (EPA) has named cyanotoxins as a candidate for federal regulation with recently published guidelines.

Historically, Des Moines Water Works had to send cyanotoxin samples to a laboratory in Florida, and wait up to three days for results.  As a result of the events in Toledo, Ohio, recently released EPA guidelines for cyanotoxins, and the increasing occurrence of cyanobacteria blooms in source waters, Des Moines Water Works has begun a more aggressive testing regimen for the presence of harmful cyanotoxins when elevated cyanobacteria levels are present in raw water sources.  Des Moines Water Works recently invested in instrumentation that will allow staff to monitor for microcystin and cylindrospermospin, per EPA recommendations, as well as two additional known cyanotoxins – Anatoxin and Saxitoxin. Des Moines Water Works now routinely samples three times per week during the warmer months of the year, and more frequently when necessary.

With increased monitoring, Des Moines Water Works has detected cyantoxins in our raw water sources.  While the presence of cyanotoxins has been detected in our raw water sources, the treatment processes have adequately prevented the toxins from reaching finished drinking water.  Des Moines Water Works staff treats for unfavorable tastes, odors, and toxins by dispersing powdered activated carbon throughout the water during the presedimentation phase of treatment.  Chlorination of the water also helps remove or destroy bad tastes, odors, and cyanotoxins.

Strategic water treatment, testing, and federal regulation of cyanotoxins are worthy, but a remedy at the source of the contaminant is more urgent. The only viable option to curtail the presence of algae that causes toxins to infiltrate our drinking water is changing upstream land practices, notably industrial agricultural production.

Short of meaningful and measurable water quality improvements in Iowa, Des Moines Water Works, and all Iowans who wish to enjoy water recreation, have no control of algal and cyanotoxins in the Raccoon or Des Moines Rivers, and must react to what flows into the river intakes. The presence of both elevated cyanobacterial levels and related cyanotoxins in Iowa’s lakes and rivers is another reminder of deteriorated water quality in the state of Iowa – forcing water utilities and water recreation enthusiasts to be on alert.

Posted by: Laura Sarcone No Comments
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