Algal bloom associated illness

• Harmful algal blooms (HABs) are the rapid growth of algae that can cause harm to animals, people, or the local ecology.
• A HAB can look like foam, scum, or mats on the surface of water and can be different colors.
• HABs can produce toxins that have caused a variety of illnesses in people and animals. HABs can occur in warm fresh, marine, or brackish waters with abundant nutrients and are becoming more frequent with climate change.

Algal bloom

Algae

• Algae are a large group of plant-like organisms usually found in water.
• They can vary in size from very small (microalgae) to very large (macroalgae) and can be found in all types of water, including marine (salt) water and fresh water.
• Like plants, algae are essential to the earth because they produce the oxygen needed to sustain life.

Algal blooms

• Algal blooms occur when algae multiply very quickly.
• Blooms can form in waters that are rich in the nutrients the algae need to grow, such as nitrogen, phosphorous, and iron.
• Warmer waters may also help algae grow quickly to form blooms.
• Blooms may become more frequent as the earth warms and the levels of nutrients in our waters increase.

Cause

In fresh water, algal blooms are most likely to form in warm, still waters that have a lot of nutrients such as phosphorus and nitrogen.

In marine and brackish (mixture of fresh and salt water) waters, a harmful algal bloom forms under certain environmental conditions, such as when:

• Existing nutrients accumulate near the surface of the ocean.
• There are increases in sea surface temperature.
• Sea currents change.
• Climate change also might increase the frequency and number of blooms or cause them to be more severe in both fresh water and marine waters.

Algal bloom off Ireland

Appearance

• An algal bloom can look like foam, scum, mats, or paint floating on the surface of water. S
• ome blooms are not visible at the water surface.
• Water bodies with an ongoing bloom may look blue, green, brown, yellow, orange, or red.
• When organisms in a bloom die and decompose, they can release unpleasant odors (like the smell of rotting plants).

Harmful algal blooms

Harmful algal blooms (also known as HABs) result from the rapid growth, or bloom, of algae that can cause harm to animals, people, or the local environment.

A harmful algal bloom can cause harm by:

• Producing toxins that can poison humans, fish, seabirds, aquatic animals, livestock, wildlife, and household pets (such as dogs) that are near the water, drink the water, or swim in the water.
• Causing illness when a person or animal eats fish or shellfish contaminated with algal toxins.
• Becoming dense enough to keep sunlight from reaching the lower depths of the water.
• Removing the oxygen from the water as it decomposes, starving fish and plants of oxygen, and damaging the local ecology.
• What types of algae can become harmful algal blooms?
• In salt water, harmful algal blooms may be called “tides” based on the color of the bloom. One example is Karenia brevis, an organism that forms the red tides sometimes seen in ocean waters along the Gulf Coast of Florida. Breathing in toxins from red tides can cause irritation of the throat and lungs.

In fresh water, such as lakes and rivers, harmful algal blooms are most commonly formed from cyanobacteria. Because of their color, they are often called blue-green algae. Although they are called bacteria, they do not cause infections in people. Instead they can harm people by creating toxic substances that people might breathe in or accidentally eat.

Geography and locations

• Harmful algal blooms are found in bodies of fresh water, marine (salt) water, and brackish water around the world. They occur in waters across the United States.
• Marine water—All coastal states in the United States have experienced harmful algal blooms, including Hawaii and Alaska.
• Harmful algal blooms in the U.S. and around the world have been associated with food poisoning.
• Imported seafood has been implicated in a number of HAB-associated poisonings in inland areas.
• Brackish water—Harmful algal blooms have been reported in brackish waters, including estuaries and coastal waters, in the United States.

Scripps La Jolla Algal Bloom

Exposure

People or animals can get sick when they have contact with water or food contaminated with algal toxins by:

• Participating in recreational activities such as swimming, kayaking, fishing, or wading through water.
• Breathing in contaminated tiny water droplets or mist from recreational activities or wind-blown sea spray.
• Drinking contaminated water.
• Eating contaminated seafood (fish or shellfish).

Boracay algal bloom cleanup

Prevention

• If you see an algal bloom, stay out of the water and keep your pets out of the water.
• You cannot tell if an algal bloom is harmful by looking at it, so it is best to be careful and avoid contact.
• If you or your pets do go in water that has an algal bloom, wash yourself or your pets off immediately afterwards with tap water.
• Do not let your pets lick their fur until you wash them off with tap water.
• When visiting lakes, rivers, or beaches, check your local water conditions, and follow any advice posted by your state or local environmental health department online or near the water.
• If you have concerns about the appearance, smell, or taste of the water, stay out of the water and contact your local park authority, environmental authority, or health department.

Algal bloom

Symptoms

Symptoms can vary depending on the type of exposure and whether the harmful algal bloom was from fresh or marine water. The symptoms also depend on the amount and type of toxin and how long the person was exposed to the contaminated water or bloom.

Symptoms can include:

• Skin, eye, nose, or throat irritation
• Abdominal pain
• Headache
• Neurological symptoms
• Vomiting
• Diarrhea

Onset of symptoms

• Symptoms from exposure to red tide blooms, such as coughing and eye irritation, start as soon as people arrive at the beach and typically end when they leave.
• Symptoms from exposure to other harmful algal bloom toxins may begin within hours of exposure and can last for a few days.
• In some cases, people can also experience liver or kidney damage.

Health effects

• The long-term health effects of harmful algal blooms in people and animals remain unclear.
• Because we are still learning about the long-term health effects, it’s important to take steps to keep people and pets safe, such as not going into water containing harmful algal blooms.

Waterbody contamination

• Harmful algal blooms in fresh water are a growing concern because they may appear in water bodies that supply tap water.
• In certain situations, toxins can contaminate tap water.
• Many water treatment plants have the ability to remove these toxins during the treatment process.
• Cyanobacteria can also produce nontoxic compounds (mixtures of elements) that are not harmful but can change the taste or smell of water.