Algae is a group of aquatic plants found in saltwater, like ocean shores, and freshwater bodies, like lakes, ponds, rivers and streams.
There are two main types of algae: seaweed and phytoplankton.
Seaweed are the large plants and phytoplankton are small, single-celled plants.
When it comes to algae and drinking water contamination, it’s these little guys you need to worry about.
When the temperatures are a bit warmer, algae can grow out of control and contaminate the water with dangerous bacteria.
When algae grows quickly, it’s called a “bloom.”
There are three main types of phytoplankton that can cause dangerous blooms:
- Cyanobacteria – blue-green algae, found in freshwater
- Dinoflagellates – microalgae or red tide found in saltwater
- Diatoms – microalgae or red tide found in saltwater
Blue-green Algae and Drinking Water Contamination
Blue-green algae, or cyanobacteria, is a type of phytoplankton bacteria that blooms in freshwater and contaminates drinking water supplies.
They’re most common in lakes and ponds where the water is more stagnant, but they can also occur in rivers and streams.
Blooms can harm people, animals and the environment because they produce toxins, use up oxygen in the water, and release harmful gasses.
As a result, blooms not only make humans and pets sick, but they can also kill fish and other aquatic wildlife.
Although ingesting algae in drinking water is the easiest way to get sick, you can also get sick by simply swimming in contaminated water.
A Closer Look At Cyanotoxins
Harmful blue-green algae blooms, or HABs, produce toxic concentrations of a chemical called cyanotoxin.
Cyanotoxins are a group of chemical contaminants formed by blue-green algae.
The most common type of cyanotoxin in freshwater is called microcystin, which is toxic to humans and animals.
Unfortunately, municipal treatment plants don’t always treat algae quickly enough when blooms first occur.
As a result, cyanotoxins have a chance to travel all the way through distribution pipes to your tap.
Risk Factors That Cause Algae Blooms
Warm weather is by far the biggest risk factor for algae and drinking water contamination.
The worst time is late summer and early fall, because there is more decaying plant matter and bacteria rotting in lakes and streams.
It’s the perfect recipe for algae blooms: warm weather plus the right nutrients.
- Levels of phosphorus and nitrogen in the water
- Fertilizer in the water from agricultural runoff
- Sewage from people and animals
- Runoff from cities and industrial buildings
- Water flow is low or moves slowly, like during a drought
- Low turbidity, or clear water allows light to reach the phytoplankton more directly and helping it grow
The summer and autumn is when nutrient levels in the water are highest, the temperatures are warm, and the water is relatively still.
With that said, although blooms are more likely to occur in the summer or fall, they can still occur any time of year.
Saltwater blooms that occur on ocean beaches have special risk factors of their own, like when deep ocean water rises and brings nutrients to the surface in a natural process called “upwelling.”
This is most common on the West Coast due to changes between the ocean and the atmosphere.
Climate change is also increasing the risk of algae in drinking water.
As the planet warms, blooms occur more often.
For example, warming temperatures in Lake Erie have increased blooms of the cyanobacteria Microcystis aeruginosa in early winter months, whereas in the past blooms already stopped by then.
Areas all over the country have experienced the same change over the last few years.
Why Algae Blooms Are Dangerous
People and animals, including pets, livestock, and wildlife, can get sick by coming into contact with cyanobacteria and other algae toxins.
- Consuming contaminated drinking water
- Eating contaminated fish or shellfish
- Swimming or playing in or near contaminated water
There are many types of algae blooms, and not all the symptoms are the same for people and animals.
Blooms in saltwater can cause different symptoms than blooms in freshwater.
Symptoms depend on how long they were exposed, the type of toxin, how much of the toxin was present, and the method of exposure (ingesting, breathing, or skin contact).
Health Effects of Algae In Drinking Water
- Vomiting
- Diarrhea
- Fever
- Headaches
- Muscle weakness
- Dizziness
- Liver damage
Common cyanotoxins that make people and animals sick include:
- Microcystin
- Cylindrospermopsin
- Anatoxin
- Guanitoxin
- Saxitoxin
- Nodularin
- Lyngbyatoxins
Long-term health effects of consuming cyanotoxins are unclear, but there is some concern that exposure to BMAA (Beta-N-methylamino-L-alanine), a compound in cyanobacteria, may be a risk factor for diseases like ALS (amyotrophic lateral sclerosis).
Some animal studies show that BMAA can cause harmful damage to the brain, but more research is needed to confirm its effects on humans.
Seafood from Contaminated Water Can Be Toxic to Eat
Eating contaminated fish can cause serious illness.
Fish, shellfish, and crustaceans that ingest the toxins in harmful algae can pass them along to the humans that eat them.
Even several weeks or months after a bloom, the toxins can linger and the fish will continue to consume them.
Fish caught in areas far away from algae contamination warning signs can still be contaminated.
This is because the cyanotoxins travel through the water, far away from obvious signs of blooms.
For this reason, if you know a bloom happened recently, it’s best to avoid any seafood caught in the area for at least a few months.
Health Effects of Swimming In Contaminated Water
What happens if you or your pets swim in algae-contaminated water?
Always avoid even the slightest contact with algae-affected water.
Affected water can have visible scum of all different colors, not just blue-green.
For example, sometimes the water can turn dark green, yellowish-brown, or red (in the ocean).
If you come in contact with contaminated water, you should remove your clothes immediately and wash yourself with clean water.
Can Your Animals Get Sick from Algae-contaminated Water?
Algae-contaminated water can be even more dangerous for animals because of their small size.
Animals, like dogs, can die within hours of consuming algae in drinking water.
Dogs are especially at high risk because of their tendency to drink the water, lap up the scum, and eat dead fish.
The same goes for livestock like cattle and horses, although it usually takes larger doses to be life-threatening.
Cattle are at risk because they’re usually restricted to a fenced area, and might be forced to drink from contaminated ponds repeatedly.
Mammals that drinking contaminated water can display the following signs:
- Fatigue
- Vomiting
- Excessive salivation
- Staggered walking
- Difficulty breathing
- Convulsions
- Liver failure
Contact your vet immediately if you notice any of these symptoms.
What You Can Do to Prevent Illness from Algae Blooms
You can take several precautions to avoid getting sick from cyanobacteria in algae blooms.
First off, if you see a bloom, stay the heck away from the water and keep your animals away too.
Don’t even take a boat on the water, because you can get sick by breathing in the toxins through the surrounding air.
Also, do not go into the water if you notice a strong earthy or musty smell, even if no discoloration is present.
A smell like this is a sign that there could be algae bloom particles in the water.
Dead fish or other dead aquatic animals is also a clear sign of a severe bloom outbreak.
You can also help reduce the risk of algae blooms in your area by keeping fertilizers away from water sources and maintaining your septic system to prevent leaks.
Government Regulations On Algae and Drinking Water
What to Do If Your Drinking Water Smells Musty or Earthy
Yep, you heard that right…
There are no official government regulations on keeping algae toxins out of drinking water!
If that nasty earthy/musty smell makes it all the way to your tap, stop drinking it immediately and do not use it to cook either.
Switch to bottled water immediately.
When blooms first happen, it can take a few days before your local water utility has a chance to react.
Once they are aware that a bloom is happening in the city’s source water, they will most likely add more chlorine and chloramine disinfectants to kill the bacteria.
Should You Install an In-home Water Filter to Protect You from Algae?
Unfortunately, there’s no way to avoid the risk of algae in drinking water during the late summer and early fall, at least if your water comes from surface water sources like lakes and rivers.
And as you just learned, it takes time for the treatment plants to react, so there is usually a small window of time where your tap can be at high risk.
Instead of leaving your health up to luck, you should consider installing a filtration system in your home.
High quality reverse osmosis (RO) systems can remove up to 99.9% of all harmful contaminants, including algae, arsenic, and lead.
They combine several stages of filtration, including a final remineralization stage to add a healthy ratio of minerals back into the water.
Cloud Water Filters also use built-in software to track and monitor your water quality 24/7 through an app on your phone.
