Toxic Algae Rampant in California, Also Spreading Nationwide

Drought has helped create optimal conditions for algae's growth
September 21, 2016 Updated: September 21, 2016

Toxic blue-green algae has been found in about 40 lakes and waterways across California—an all-time high and twice as bad as last year.

The growing extent of the algae caught water agencies off-guard, reported the East Bay Times on Sunday.

The cyanobacterial toxins in these algal blooms can easily kill dogs or wildlife and can cause a variety of symptoms in humans, including difficulty breathing, fever, and vomiting. There have been rare cases of human fatalities.

Drought in California has created optimal conditions for the algae to flourish. Stagnant water, high temperatures, and too much nitrogen and phosphorus in agricultural run-off (from fertilizer) are to blame.

But the World Health Organization reports that all 50 states are affected by the toxic algae. Coastal blooms and those in the Great Lakes have received the most attention from officials thus far, but inland freshwater blooms are an emerging concern.

Monitoring and regulation related to harmful algal blooms (HABs) has been limited, not only in recreational waters but also in drinking water, though great strides have been made over the past year.

The U.S. National Oceanic and Atmospheric Administration (NOAA), which oversees HABs research, reported that the blooms on Lake Erie were the worst ever in 2015, covering some 300 square miles. An unprecedented bloom also stretched in coastal waters from central California up to Alaska.

Marine HABs alone have an average annual cost of $82 million due to impacts on health, tourism, and the seafood industry. That’s a conservative estimate, according to NOAA. The added costs incurred by freshwater blooms are as yet unknown.

Drinking Water

The U.S. Environmental Protection Agency (EPA), which is responsible for drinking water regulation, has included toxins from the algal blooms in its most recent Unregulated Contaminant Monitoring Rule (UCMR).

Under the UCMR, EPA identifies 30 currently unregulated contaminants every five years and monitors them in municipal water supplies to see how prevalent they are, whether they are of concern to human health, and whether they should be regulated.

While EPA is focused on four particular toxins produced by the algal blooms, “there’s always the risk that cyanobacteria may produce other bioactive metabolites that might still be a risk,” said microbiologist Tim Otten, Ph.D. in an email. He uses DNA-based tools at the Bend Genetics lab in Sacramento to monitor water quality.

Otten gave the example of a recently identified amino acid produced by cyanobacteria, BMAA, that has been linked to neurological diseases. Otten believes we should use the so-called “precautionary principle,” which basically states, “better safe than sorry.”

Otten believes we should use the so-called ‘precautionary principle,’ which basically states, ‘better safe than sorry.’

Even if a bloom is deemed ‘nontoxic,’ he said, it’s best not to go near water covered with a green film and not to let pets near it. 

California’s state officials are taking cyanobacteria seriously and California is at the forefront of HAB monitoring, Otten said. But, he said, “The freshwater monitoring programs around the country, and even in California, are a decade (or more) behind what has been implemented for marine harmful algal blooms which are overseen by NOAA and the FDA (seafood).”

It was only after Toledo, Ohio—a city of about 500,000 people—had its drinking water shut down due to HABs in 2014 that states started to ramp up their freshwater monitoring.

NOAA spokesperson Ben Sherman said via email that NOAA’s HAB drinking water research is currently focused on the Great Lakes, but it can have broad applications.


California’s State Water Resources Control Board rolled out a strategy for tackling freshwater HABs in January. It includes using satellite imagery to identify blooms and a centralized reporting system, among other measures.

Otten said that, even so, the state will never be able to monitor all water bodies, so public education is paramount. “The analogy I like to give is that the health department cannot post a warning sign on every sprig of poison oak or poison ivy. Instead, if an individual wants to recreate in places where these may occur, it’s up to them to learn what they look like and avoid them.”

The analogy I like to give is that the health department cannot post a warning sign on every sprig of poison oak or poison ivy.
— Tim Otten, microbiologist

The onus is also on individual Americans to report blooms. The Centers for Disease Control launched the first national reporting system for HABs in June, the One Health Harmful Algal Bloom System.  

A partnership between federal agencies is undertaking a $3.6 million effort to create a national satellite-based algal monitoring network, Sherman said. 

Some lake managers in California are trying to kill the algae with herbicides, according to the East Bay Times. But Otten warned that some cyanobacteria can actually feed on the nitrogen and phosphorus molecules in herbicides. As an emergency measure, he said, hydrogen peroxide may work.

The best solutions, according to Otten, are to reduce nutrients from farm run-off and to increase flushing rates in water bodies.