Algal Bloom Season is Upon Us – Preparing to Keep Our Communities Safe

U.S. EPA issues a Health Advisory on Cyanotoxins in Water Supplies.

The water community is well-aware that many factors, including increasing temperatures, general urbanization, and high nitrogen and phosphorus loading of source waters, are contributing to more frequent and intense cyanotoxin, or algal toxin, levels in freshwater and marine environments.

The water community is also well-aware that summer brings a natural, seasonal uptick of algal blooms. It was, after all, just last summer that a serious cyanotoxin event in Toledo led to a “do not drink” advisory for 400,000 people. These factors combined make for a perfect storm of events that the water community must be prepared to address.Toxic_Algae_Bloom_in_Lake_Erie

The Environmental Protection Agency (EPA) recently issued a drinking water health advisory (HA) for water utilities and states to use as they take steps to protect the public from cyanotoxins. Specifically, the EPA issued a 10-Day drinking water HA for the cyanobacterial toxins microcystins and cylindrospermopsin. EPA recommends HA levels at or below 0.3 micrograms per liter for microcystins and 0.7 micrograms per liter for cylindrospermopsin in drinking water for children less than six years old. It also recommends HA levels for drinking water at or below 1.6 micrograms per liter for microcystins and 3.0 micrograms per liter for cylindrospermopsin for children seven years in age through adults.

When these types of advisories are issued, water utilities have to be ready. Revisit the data available to you, take stock of what questions or needs your communities may have, and as always, seek more information when you need it.

The water community has held the line in managing, understanding and responding to cyanotoxin events for years. There is no doubt that we will stay true to this mission. It’s important that the water community stay on top of what science is telling us about cyanotoxins, and that we stay on top of how best to communicate this issue to the communities we serve. Citizens look to us for help in understanding what cyanotoxins are and how we can protect our water supplies from them.

The EPA’s recent health advisory is a reminder of how the water community stays sharp on its knowledge. When these types of advisories are issued, water utilities have to be ready. Revisit the data available to you, take stock of what questions or needs your communities may have, and as always, seek more information when you need it. The Water Research Foundation (WRF) has a number of recently published and updated resources to help water utilities prepare for cyanobacterial events and identify monitoring, mitigation, and treatment strategies. Some of these resources include:

  • The WRF’s state of the science paper which provides an up-to-date overview of cyanotoxins in water along with descriptions and links to other key WRF reports and resources.
  • Because utilities must be prepared to speak about cyanotoxins, not just understand the science and procedures in play, WRF and AWWA have published A Water Utility Manager’s Guide to Cyanotoxins (project #4548). In a simple Q&A format, this guide helps to address cyanotoxin occurrence, source water management, and treatment strategies. Note: a more technical companion document is also in development.
  • For the more visual learners out there, WRF has multiple cyanotoxin webcasts archived:
  • Managing and Mitigating Cyanotoxins in Water Supplies conducted in 2014 previews information included in the Utility Manager guide.
  • Preparing for and Mitigating Algae Blooms and Cyanotoxins — The Utility Perspective, held in April 2015, provides case studies on standard operating procedures that answer (1) when and how a utility should monitor for algae, based on levels and frequency; (2) when a utility should start cyanotoxin monitoring, how frequently, and where; (3) what analytical methods a utility should use and what are the triggers for using different analytical methods; and (4) what treatment preparation and actions should be taken in the event of toxin presence in the source water.
  • Optimizing Conventional Treatment for Removal of Cyanobacteria and Toxins (project #4315), also published in 2015, supplies water quality managers and water treatment plant operators with knowledge and tools required to confidently apply conventional water treatment processes in the event of source water contamination with cyanobacteria.

The matter of cyanotoxins is not likely to go away any time soon – or ever, for that matter. That shouldn’t be cause for concern, however. These are naturally-occurring bacteria that when understood, can be managed from a treatment perspective. The task sits with us to continue to educate ourselves on these algal toxins and ensure our utilities operate in a manner that make that threat removal a reality.


Robert Renner is the Executive Director of the Water Research Foundation