Skip to content

EPA Science In Action: Keeping an Eye on Harmful Algal Blooms

2014 August 12

By Cindy Sonich-Mullin

A half million people living in and around Toledo, Ohio recently experienced a weekend without tap water. A “harmful algal bloom” of cyanobacteria in Lake Erie, Toledo’s water source, produced unsafe levels of the toxin microcystin. The toxin is known to cause abdominal pain, nausea, vomiting, and at high exposure levels, liver damage.

A water advisory was issued alerting residents to avoid all contact with Toledo drinking water.

At the first sign of trouble, colleagues at the Ohio Environmental Protection Agency contacted my laboratory to provide technical assistance and water sample analysis to support the City of Toledo’s drinking water utility.

We were a natural choice to help out. Not only is EPA’s Cincinnati-based laboratory facility relatively close geographically, but our scientific staff includes a team of leading experts with analytical capabilities in drinking water treatment and cyanobacterial toxins.

Throughout the weekend, we performed tests and conducted sensitive analyses to help identify the optimal approach for controlling the toxins in Toledo’s water plant and distribution system.  We shared our test results with our partners from Ohio EPA, who interpreted them along with their own results and others from the City of Toledo.

We were all greatly relieved the morning of August 6th, when the City of Toledo determined that they could lift the water advisory.

At the time, Ohio EPA Director Craig Butler released the following statement: “After exhaustive testing, analysis and discussions between Toledo water officials, the U.S. EPA and the Ohio EPA, we support the city’s decision to lift its drinking water advisory. Throughout the difficulty of the past few days everyone involved has demonstrated the utmost professionalism and commitment to solving this problem. The mayor and his team, U.S. EPA and the other scientific and academic leaders who lent us their expertise worked in a constructive way to turn the water back on for the people of Toledo.”

While many weekend plans were cancelled due to the crisis in Toledo, we were honored to be called on to help our sister city to the north. As scientists, it is gratifying to use our expertise and the tools we develop to provide solutions to communities. Of course, what would be even better than lending our expertise and rapid response and analysis capabilities would be to help prevent harmful algal blooms from threatening drinking water supplies in the first place. And that is just what we are doing. In fact, we’ve shared some of our harmful algal bloom research recently here on our blog. Below are some recent posts with more information on that work.

As the above blogs exemplify, EPA researchers are working hard to better understand the dynamics of harmful algal blooms. EPA is also working with other agencies to accelerate the development and deployment of affordable sensors that will help predict future algal blooms. This means we will be even better poised to work with cities like Toledo and other local communities to better protect precious drinking water supplies. Keep an eye here on “It All Starts with Science” to see future posts about that work, and more.

About the Author: Cindy Sonich-Mullin is the Director of EPA’s National Risk Management Research Laboratory in Cincinnati, Ohio. She has over 30 years of experience in EPA, leading research and response efforts on a wide variety of environmental issues.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

Please share this post. However, please don't change the title or the content. If you do make changes, don't attribute the edited title or content to EPA or the author.

6 Responses leave one →
  1. Nick permalink
    August 12, 2014

    What are the odds it will come back?

    • SamAtEPA permalink*
      August 14, 2014

      Thanks for the question, Nick. Cyanobacteria occur naturally in freshwater and have been present in aquatic ecosystems for a very long time (their first occurrence dates back at least 2.7 billion years ago!). Cyanobacteria are generally present (but not necessarily present in large quantities as blooms) in freshwater bodies in the US. There are also many physical and chemical factors that contribute to the formation and persistence of cyanobacterial blooms in freshwater bodies.

      Also, harmful algal blooms are not unique to Toledo or Lake Erie. So, in areas across the country where sourcewater is susceptible to blooms, drinking water and wastewater utilities work closely with their state agencies to monitor for toxins and adjust treatment as necessary to ensure the quality of the tap water.

  2. Annette kraina permalink
    August 14, 2014

    I know a company that a friend works for that has been taking there dirty frac water from the drilling industry in Steubenville, Ohio, that is not properly disposing of the waste from the fracture water, and is just covering it up when they clean the trucks, and dump, how do i report this i cannot find it on the website. The company he works for is also, making billions of dollars, and i can’t find them by where they are located in Empire ohio, what do i need to do?

    • SamAtEPA permalink*
      August 14, 2014

      Annette, you can report illegal disposal of wastes or other non-emergency suspicious activity related to oil and natural gas development through

  3. Sean Lyden permalink
    September 5, 2014

    What specific actions are the EPA taking to have this problem alleviated going forward? Is there pressure being put on the individuals responsible for the nutrients flowing out into our common waterways to change their practices? All I have read about is more sensors to alert when there is a problem rather than addressing the problem at the source.

  4. Aaron@EPA permalink*
    September 9, 2014

    Thanks for the question, Sean. EPA is actively working with partners across the country to meet the challenges posed by nutrient pollution flowing into our waterways. For more specifics of those actions, please visit:

Leave a Reply

Note: You can use basic XHTML in your comments. Your email address will never be published.

Subscribe to this comment feed via RSS