Algae bloom may be behind mysterious California deaths

ASU algae expert explains one of the deadliest toxins on the planet

Algae bloom in pond

On a remote trail in California’s Sierra National Forest called the Devil’s Gulch, a family of three and their dog were recently found dead. Authorities were at a loss to explain what happened.

"I've worked in different capacities, but I've never seen a death like this," the county sheriff told the press.

It turns out the family might have been exposed to a poison deadlier than nerve gas: toxic algae, one of the deadliest toxin on the planet.

Unofficially, it is called Very Fast Death Factor. The CIA reportedly uses it in suicide pills for agents likely to be captured by the enemy. It has caused entire towns along the Italian coast to be evacuated. And it may have been the cause of a mass die-off of an African elephant herd.

Last month, the Sierra National Forest — part of the U.S. Forest Service — announced that "a high concentration of algae bloom" had been found in the Merced River.

"The Sierra National Forest (SNF) would like to inform those visitors who like to enjoy this area of the Merced River and SNF, not to swim, wade or allow their pets to enjoy the water," the agency announced.

ASU News talked to Taylor Weiss, an Arizona State University assistant professor in environmental and resource management in the Polytechnic School and a member of the Arizona Center for Algae Technology and Innovation — where research is being done to harness algae technology to produce renewable energy, food, feed and other valuable products, while performing environmental services to support a more sustainable future for society — about this deadly substance. 

Question: My first thought was, I didn't know that algae could kill.

Answer: It is among the most deadly toxins on the entire planet. If you made a list of like the top 10, VX gas-synthetic (a nerve agent) would only be one of the top 10. All the rest are held by algae. ...

The tidbit of history that people gloss over is that the CIA actually stopped issuing cyanide capsules a long time ago. But we know for a fact that U-2 pilots who flew over Russia were issued fake coins with needles in them laced with saxitoxin to kill themselves in the event of torture. So we know what they do. We know the most highly effective chemical weapons designed mimic their activities. They accomplish the same goal. They are paralytic agents that paralyze your nerves that control your skeletal muscles. They lead to your diaphragm becoming unable to move, which means you suffocate, as almost certainly what seems to have happened to this particular family on this occasion.

When (authorities) were concerned about toxic gases for mines and immediately they'd say they were looking for carbon monoxide poisoning, it's just that they died quickly and suffocated. Many of the other toxins that most of the time we pay attention to — which are liver toxin, hepatotoxins, like a poisonous mushroom — those take days or weeks usually to kill. But literally saxitoxin’s unofficial name is Very Fast Death Factor. It kills very quickly. So you should have it in the same mindset as a chemical weapon.

Q: So this family was out with their dog. Would they be next to a creek or a puddle?

A: It’s the same reason why pets die from it, especially dogs. The dogs go in the water, they swim in it and they come back with the algae sticking to their fur in particular, and then they lick it off or people wipe their hands on the dog or something like that. We had pet deaths in Arizona earlier this year from the same thing. ... Some of these compounds, they volatilize. They can literally just be off-gas in the air. So you don't need to go into the water to be exposed to it.

There were major blooms of some of these toxins off of Italy about five years ago. Entire villages were evacuated because the air was poisoning them enough that everybody was affected. These are no joke. And you don't know that they're there. They’re ephemeral, so they come and go. However, blooms are natural. The toxins are natural. But having lots of algae producing lots of the toxin, and there's certainly grades of toxins, it's difficult to keep track of. It's not very common. It’s one of these incredibly high-risk but low-probability events that just is very difficult to sort of get and stay on top of.

Q: If you were out on a hike, what would be some warning signs that it was nearby?

A: I would look to regulations on the books. So the World Health Organization issued regulations about 10 years ago on the standard by which advisories any country anywhere should basically make actions for, recreational and drinking and other uses like that. Basically, if there's a lot of algae in the water, there's a lot of chlorophyll, i.e. the algae are very active, so they'll be able to make lots. And then number three is, are they cyanobacteria? Other types of algae can be toxic, but the cyanobacteria are the most common. (Cyanobacteria is blue-green and smells like freshly cut grass.) So those three standards, basically, you keep track of them.

And so in an event where you have lots of cyanobacteria, and they're doing a lot of photosynthesis and they're there in high numbers very rapidly, you should be very concerned. We do not have federal guidelines in the United States. The problem is somewhat unequally spread between states. It means state regulators are really responsible for monitoring and enforcing things ... and so it also varies by state. Obviously in California, they do monitor areas where people come into contact with water on a more routine basis. But if it's in a more rural area, this is where we hear these stories all the time. It's basically, the water's not monitored and people, their pets or animals come into contact with it. Nobody's paying attention, and on rare occasion, these very bad things happen.

Q: So a good rule of thumb would be if you see a pool or a pond or a puddle with a lot of algae, stay away from it.

A: If a regulator has put up warning signs saying to avoid the area, follow them. ... I would take the warnings more strongly than even (what) the regulators themselves often post. There is always pushback on a recreational side. Cities don't want to declare suddenly you can't go swimming and spend summer dollars and vacation. They don't like that. And because these events can be very ephemeral, right? Maybe it's one day it's harmful, but you're killing the whole rest of the summer. There's always that conflict. So regulators will be very cautious, but they're kind of putting responsibility on you.

If there isn't an issued warning and you're out in nature and things like that, the problem is with these very toxic algae, you may not see any problems. It may appear to be free and clear water. There could be a bloom somewhere else, but just carrying the toxins downstream. ... There is no great rule of thumb, except if you don't know the water, don't trust the water. And in particular, what I would say is, in the summertime it is more likely to be cyanobacteria, so to be more cautious. This is why swimming is the bigger problem. People don't tend to swim in the water in the winter, but that's also the safer time.

Top image by Gina Janosch from Pixabay

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