TOXIC, NOXIOUS, AND SMELLY ALGAE (PART 2)

Remember, cyanobacteria get their name because they've got this blue-green pigment called phycocyanin. This helps them with photosynthesis, but also makes them appear these different colors, blue, green, even black in color. Now, these do fall in our definition of algae. They are in that no true roots, stems, or leaves category, but they're very different than any other algae out there because they are truly a type of bacteria.

Cyanobacteria can grow in almost every habitat you can imagine, from caves to turfgrass and lawns, desert crusts, hot springs, even in the snow. It’s a very, very diverse group, and they can grow almost anywhere. However, they thrive in many surface waters throughout the country, and that's what we're going to focus on today: blooms of cyanobacteria in lakes, ponds, reservoirs, and other surface waters.

Some of the largest cyanobacteria blooms ever recorded have occurred in the recent past. Some high-profile sites that you may know of include Lake Erie, Grand Lake St. Mary’s, Discovery Bay in California, and Jordan Lake. There was even a state of emergency in Florida a couple years ago due to thick cyanobacteria infestations.

It’s very important to acknowledge that cyanobacteria have very different growth strategies and growth forms, so you know how to look for them in a water resource.

First we’ll look at this thick scum form. These scum forming blooms are pretty common, and pretty easy to identify. Many types of planktonic colonial cyanobacteria can produce these scum-forming blooms, like microcystis, aphanizomenon, and dolichospermum. They typically have a bluish or blue-green tint.

So what's so bad about these cyanobacteria? First, they're smelly. Smelly means a lot of them can produce taste and odor compounds.

Methyl-isoborneol and geosmin are some of the common compounds they produce. These are both fishy and dirty flavored. They can make your drinking water smell bad and taste terrible to the point you can't even use it. You can't drink it, and you can't use it in cooking, because it smells so bad.

These compounds are called toxins, which we defined in the first episode. But, again, toxins are something biologically produced by these organisms that negatively influence other organisms at common levels found in the environment.

Many types of toxins exist including neurotoxins, liver toxins, gastrointestinal toxins, and skin toxins. Cyanobacteria can produce all of these. They can impact both humans and wildlife and can cause diseases. Some of the neurotoxins can produce ALS and Alzheimer's. Liver toxins can cause liver failure and liver cancer.

Many of these toxins have been documented to cause severe impacts to wildlife that use the water as well. The neurotoxins can move through the food chain.

There's one in particular that has caused mortalities of bald eagles and even killed a herd of wild elk. Livestock that drink out of the water are at risk. There's a lot of cyanobacteria blooms in livestock watering systems and ponds, and they can cause documented mortality of cows, pigs, sheep, and other species.

And during the state of emergency in Florida, there were many people that went to the hospital that felt nauseous and dizzy from breathing in some of these cyanobacteria toxins that can become aerosolized.

Utah Lake was the same way. Many children were getting sick from playing in the water or just being near the lake that was full of microcystins.

There are also guidelines for recreational waters, which are four and eight parts per billion of these toxins. So there are low levels in both recreational exposures and extremely low levels in drinking water exposures.

The World Health Organization has also put microcystins on the possible human carcinogen list and links have been made to liver cancer and diseases from drinking water exposures. There are clusters of neurodegenerative diseases that have been described from exposures to neurotoxins like BMAA and anatoxin. ALS clusters and Alzheimer’s clusters have been identified from links with chronic cyanobacteria blooms.

We are exposed to these cyanobacterial toxins in many different ways. First, we're exposed through the food chain. Fish that have been swimming around in toxic cyanobacterial infested waters can accumulate the toxin, and we can eat those.

Another way is through the marine food web. I know these cyanobacteria are mostly fresh water, built up in fresh water systems, but sometimes these toxins are flushed down to marine environments. They can build up through fish and shellfish in the marine environment and we can be exposed to these freshwater toxins in that way as well.

There's one other food that they can build up in: irrigated crops. Crops irrigated from toxin-laden water. Cyanobacteria-infested water is often sprayed on fruits and vegetables, and those can build up toxins in the fruit. So, through the food chain, through this consumption pathway, we can be exposed to cyanobacterial toxins.

Since the concentration levels are just guidelines on toxins in drinking water, there are not necessarily mandated regulations yet. That means your drinking water plant may or may not spend the money to actually test for these toxins in the drinking water process. They can be removed in the process, but might not be depending on the processes implemented in your plant.

Another route of exposure is the inhalation route of exposure. This is where you breathe in either the toxin itself or small cyanobacteria cells that may arise out of the water column.

This is a very important route of exposure. First of all, because it can do some potent things. These neurotoxins can go straight to your brain and impact you in significant ways as a result of this inhalation exposure.

So it’s safe to say that simply shutting down the lake is not without risk. If you put up a sign to close the lake and try to stay out of it, that may offset some exposure routes.

If you limit how many fish you eat out of there and if your drinking water plant is up to par, that may limit some exposure routes, but there are a lot of people that live near cyanobacteria infested waters that are being exposed to these toxins through this inhalation exposure. Just breathing it in as it comes out of the water column. So it is very important to note that route of exposure.

The last route of exposure that I want to mention today is the recreational water route. This occurs by directly swimming in the water body that has cyanobacteria in it.

It also could be fishing or boating or any other recreational activities in cyanobacteria-infested waters. Remember that children are highly sensitive to these cyanobacterial toxins, and allowing children to swim in there is not without risk.

One other point here is that often you see those big scums and mats and most people don't want to go swimming in those anyway, but remember there can be cyanobacteria distributed through the water column. Those small planktonic forms can be very potent and very hard to detect unless you happen to be carrying around a microscope with you.

The best way to ensure you don't get exposed to these cyanobacteria and these cyanobacteria toxins is to go after the source. Don't let those cyanobacteria grow. Don't let them exist in your water body.

Go after them before they can achieve levels that can produce toxins that would cause a concern. Keep them below threshold levels, out of your water body, so your kids can't be exposed, so they won't hurt you, and they won't hurt the wildlife.