Surprising Reason for Toxic Water Crisis

toxic water crisis

Story at-a-glance

  • Phosphorus is a known driver of toxic blue-green algae, or cyanobacteria, as they use it readily for fuel
  • Glyphosate is a synthetic phosphonate herbicide and cyanobacteria can utilize the phosphonate portion of the glyphosate molecule for “food”
  • Toxic algae may be thriving, in part, due to increasing usage of glyphosate, which was found to be likely to stimulate algal blooms
  • Glyphosate is also capable of releasing phosphorus from the soil and spikes in dissolved reactive phosphorus (DRP) runoff have increased with increased use of glyphosate


This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.

By Dr. Mercola

If you live near a lake in the U.S., you may have noticed signs warning of toxic blue-green algae, or cyanobacteria. Such warnings, advising swimmers and boaters to stay out of the water, and keep pets away as well, are becoming increasingly common as the thick, green muck appears on once-pristine waterways. Blue-green algae make up a portion of the phytoplankton in many bodies of water,1 and they're not inherently dangerous or even altogether unusual.

According to the Wisconsin Department of Natural Resources (DNR), fossil evidence suggests blue-green algae have been around for millions of years, with algal blooms dating back to the 12th century. However, the agency notes, "[I]t is possible that the frequency and duration of blooms are increasing in some Wisconsin waters as a result of increased nutrient concentrations."2

The problem of increasing algal blooms is not unique to Wisconsin — it's happening all over the U.S., particularly in agricultural areas where the use of phosphorus-based fertilizers is prolific.

Phosphorus is a known driver of blue-green algae, as they use it readily for fuel. Researchers have uncovered another, relatively surprising, source of phosphorus that also appears to be driving the toxic algae growth to unprecedented levels — glyphosate, the active ingredient in Roundup herbicide.

Glyphosate May Be Driving Up Rates of Toxic Algae

Glyphosate is a synthetic phosphonate herbicide and is the most heavily used agricultural chemical of all time. In the U.S., over 1.6 billion kilograms of the chemical have been applied since 1974.3 It was long believed that plankton could not access phosphonates like glyphosate as a fuel source, but in 2009 R. Michael McKay and George Bullerjahn of Bowling Green State University in Ohio showed that this is not the case.

Instead, they found that cyanobacteria can utilize the phosphonate portion of the glyphosate molecule.4 In a report released by the Ohio Environmental Protection Agency (EPA) — the Ohio Lake Erie Phosphorus Task Force Final Report — it's stated, "The researchers estimate that as much as 1,000 metric tons [about 2.2 million pounds] of Roundup is applied to Lake Erie's watershed per year, and it is being detected in adjacent waterways particularly in the spring."5 Bullerjahn further stated in an Ohio State University news release:6

"It turns out that many cyanobacteria present in Lake Erie have the genes allowing the uptake of phosphonates, and these cyanobacteria can grow using glyphosate and other phosphonates as a sole source of phosphorus."

Lake Erie has been struggling with algae blooms due to manure, sewage and fertilizer runoff, as well as runoffs from glyphosate applications, leading to contaminated drinking water and fish die-offs for decades. Algae-triggered "dead zones" in the lake are now larger than they've been since the '80s and cover 25 percent of the entire lake.7 Further, in 2017 the lake's algal blooms were recorded as the third-largest on record.8

Spikes in Phosphorus in Lake Erie Watershed Linked to Planting of GE Crops

Adding to the evidence that glyphosate could be playing a role is research by Ohio Northern University chemist Christopher Spiese and colleagues, who suggested that spikes in dissolved reactive phosphorus (DRP) runoff that have increased since the mid-1990s coincided with an increased use of glyphosate.

At the 2016 Conservation Tillage and Technology Conference, Spiese shared the results of his study, which found a significant correlation between DRP loads and the number of acres planted with herbicide-tolerant genetically engineered (GE) crops (which are heavily sprayed with Roundup). "For every acre of Roundup Ready soybeans and corn that you plant, it works out to be about one-third of a pound of P coming down the Maumee [watershed and into Lake Erie]," Spiese told Sustainable Pulse.9

Spiese also found that glyphosate is capable of releasing phosphorus from the soil and conducted studies to see what happens when soil samples were applied with phosphorus and then sprayed with glyphosate. Some of the samples showed significant phosphorus release, with "hot spots" likely contributing a significant amount of DRP. Sustainable Pulse reported:10

"Based on the average two glyphosate applications growers make every year, Spiese estimates that overall, 20 [to] 25% of the DRP runoff is caused by glyphosate. But depending on the location within the watershed, that percentage could be much lower or much greater."

In February 2016, the U.S. and Canada announced plans to reduce the amount of phosphorus entering Lake Erie by 40 percent by 2025,11 but it's seeming increasingly clear that reaching this goal must take into account not only fertilizer runoff but also glyphosate applications. The problem has gotten so bad in the area that even drinking water has been affected.

In 2014, citizens in Toledo, Ohio, were warned not to drink their tap water as it was found to contain significantly elevated levels of microcystins, caused by algae blooms in Lake Erie.12 Microcystins are nerve toxins produced by some blue-green algae that can cause fever, headaches, vomiting and seizures.

The city and surrounding areas became the first to report drinking water-associated outbreaks caused by harmful algal blooms, as highlighted in the U.S. Centers for Disease Control and Prevention's (CDC) November 2017 surveillance for waterborne disease outbreaks report.13

"The cyanobacterial toxin microcystin caused the largest reported toxin contamination of community drinking water in August 2013 and September 2014 and was responsible for extensive community and water disruptions," the CDC noted.14 The agency is now tracking harmful algal blooms (HABs) via its One Health Harmful Algal Bloom System (OHHABS), calling them an "emerging public health issue."15

Toxic Algae Using Toxic Roundup for Food

In short, it appears that toxic algae are thriving, in part, due to increasing usage of glyphosate. In another report by Bullerjahn and colleagues, it's noted that, "Glyphosate is a phosphonate that can be used by cyanobacteria as a source of phosphorus" and is 'likely to stimulate algal blooms."16

Interestingly, separate research published in 2016 also revealed that glyphosate has an effect on phytoplankton — in some cases leading to its growth and in other cases proving to be toxic or having no effect. Writing in PLOS One, the researchers explained:17

"[G]lyphosate could be used as P-source by some species while is toxic to some other species and yet has no effects on others. The observed differential effects suggest that the continued use of glyphosate and increasing concentration of this herbicide in the coastal waters will likely exert significant impact on coastal marine phytoplankton community structure."

Unfortunately, glyphosate is but one agricultural chemical that is wreaking havoc on lakes, streams and other bodies of water. Runoff from synthetic chemical fertilizers as well as the excessive amounts of manure from concentrated animal feeding operations (CAFOs) that's often sprayed onto farm fields are also highly problematic. In fact, an AP investigation revealed alarming trends, including that levels of nitrogen and phosphorus from fertilizer runoff are getting higher in lakes and streams.

Further, despite government agencies spending billions of dollars to help farmers prevent fertilizer runoff and circumvent the problem, algae blooms are getting worse instead of better.18 Overall, the EPA states that about 15,000 water bodies have been identified that have "nutrient-related problems,"19 and many more probably have yet to be identified.

Outside the U.S., meanwhile, algal blooms spanning thousands of miles have been recorded in China and Australia, while microcystin has been detected in more than 240 bodies of water in Canada. In Greece, Italy and Spain, algal blooms are also a problem and estimated to cost the economy $355 million annually.20

The Problem With Toxic Algae

Blue-green algae is smelly and can lead to discolored, foul-tasting water, but that's just the start. One way blue-green algae become toxic is by virtue of its thick density, which blocks light and can deplete oxygen in the water, leading to dead zones. Wisconsin DNR explained:21

"[W]hen blue-green algae reach bloom densities, they can actually reduce light penetration, which can adversely affect other aquatic organisms both directly (e.g., other phytoplankton and aquatic plants) and indirectly (e.g., zooplankton and fish that depend on phytoplankton and plants) … When a blue-green algae bloom dies off, the blue-green algae cells sink and are broken down by microbes.

This breakdown process requires oxygen and can create a biological oxygen demand. Increases in biological oxygen demand result in decreases in oxygen concentration in the water, and this can adversely affect fish and other aquatic life, and can even result in fish kills."

The other major problem stems from toxic chemical compounds that are naturally produced by some types of blue-green algae. Harmful to humans, pets and marine life, the toxins may lead to skin rashes and respiratory issues, and, should they get into an open wound, may even lead to a staph infection.22 A type of cyanobacteria called microcystins are nerve toxins that may lead to nausea, vomiting, headaches, seizures and long-term liver disease if ingested in drinking water.23

Researchers are also looking into whether another toxin, BMAA (Beta-N-Methylamino-L-alanine), in blue-green algae may be linked to neurological diseases like Alzheimer's, Parkinson's and amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease).24

You can be exposed to algae toxins via direct contact with the water or algae, breathing in the toxins in the air or even by eating fish or shellfish that have eaten toxic algae.25 What makes toxic algae even more troubling is that you can't tell which types are toxic by looking at them. Wisconsin DNR continued:26

"These [toxic] chemicals are not produced all of the time and there is no easy way to tell when blue-green algae are producing them and when they are not. When the cells are broken open, the toxins may be released. Sometimes this occurs when the cells die off naturally and they break open as they sink and decay in a lake or pond.

Cells may also be broken open when the water is treated with chemicals meant to kill algae, and when cells are swallowed and mixed with digestive acids in the stomachs of people or animals. The only way to be sure if the toxins are present is to have water samples analyzed in a laboratory using sophisticated equipment."

Changes in Agriculture Are Necessary to Stop the 'Green Plague'

Many of the world's lakes are at risk due to agricultural chemicals feeding harmful blue-green algae. The answer, according to the researchers, is better land-use management that addresses fertilizer runoff. Dramatic reductions in synthetic fertilizer use are also recommended, and hopefully it won't be long until a similar recommendation is made for glyphosate as well.

The effects of agricultural runoff on water quality are finally starting to be addressed in some areas, where farmers are trying new conservation methods to ward off toxic runoff and protect water quality. This includes strategies such as building "artificial wetlands and underground 'bioreactors' to capture nutrients in drainage systems," according to The Christian Science Monitor.27 Others have started using cover crops and no-till methods to slow fertilizer and pesticide runoff.

On an individual level, you can help by buying food from organic farmers who are not using glyphosate and instead rely on natural methods and soil-regenerative techniques, such as no till, cover crops, composting and livestock integration. This will naturally help you to eat better too, since typically only real whole foods are grown this way (while most processed foods are the product of destructive industrial nitrogen fertilizer-laden and glyphosate-heavy agriculture).

It's important to note that if you see signs warning of harmful algae blooms, stay out of the water and keep your pets out too. Even if there are no signs present, avoid entering water that smells bad, looks discolored or has foam, scum or algae mats on the surface.28 If you suspect there could be a problem, you're better off safe than sorry, and be aware that algae toxins can be present in the water even if there's no visible algae on the surface.

In addition, avoid consuming any water that could be contaminated with algae toxins, even if the water has been boiled. According to the U.S. Centers for Disease Control and Prevention (CDC), "Boiling water does not remove algal toxins and can increase the amount of toxin in the water by concentrating it,"29 so you'll need to find an alternative source of water if an advisory is issued in your area.


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