Exposure: Blue-Green Algae
(c) Jason Zheng
Blue-Green Algae Brief by Lindsay Boyce MPH Candidate
Cyanobacteria also known commonly as Blue-Green Algae grow in any type of water and uses sunlight to create food to support life. This bacterium is usually too small to be seen but can create colonies called algae blooms that are visible to the naked eye.
Some cyanobacteria can create harmful blooms know as CyanHABs. These blooms are harmful to both humans and animals. They are dangerous for many reasons including, dense blooms can block sunlight and oxygen from the water killing off the plant and animal life that are living in the particular water source. Also, some cyanHABs can produce natural toxins; these toxins can make animals and humans sick. The first sign the HAB exists is a sick dog or other pet that has been swimming in an algae laden watering hole. Children are at a greater risk than adults due to the fact that they are smaller in size and can get a large dose of toxin if exposed.
Exposure to these toxins comes in many forms; drinking water that comes from a lake or other water source with CyanHABs. Using recreational waters that are contaminated with CyanHABs and also aerosols inhaled from water the lawn.
The symptoms and or illnesses associated with this type of toxin are rash, nausea and or vomiting other gastrointestinal disorders, liver toxicity, and neurotoxicity.
Prevention is important to limiting exposure. Not swimming or participating in other recreational activities involving water where cyanobacteria exist. Do not let pets swim in areas where water is discolored or where you can visibly see algae. Also, it is important to report any musty smelling or bad tasting water to a utility company.
A reduction of the use of pesticides and fertilizers will help in eliminating the progression of blue green algae. Also, proper maintenance of the septic system and using natural vegetation to buffer incoming water into ponds and lakes are important ways in the prevention of Blue-Green Algae.
Toxicity of Blue-Green Algae
by Katherine Fite
Blue-green algae, also known as cyanobacteria, are a group of photosynthetic organisms. There are dozens of species that thrive on land and in fresh and marine water environments. Blue-green algae are usually found in ponds, lakes and other slow-moving waters. Algal blooms occur under certain conditions. In warmer weather, with high levels of nutrients such as nitrogen and phosphorous, algal blooms flourish. While most algae blooms in the summer months, some species are known to grow in colder conditions.
There are dozens of species of algae that produce toxins. The toxins produced by cyanobacteria are called cyanotoxins. There are several types of cyanotoxins: hepatoxins are toxins that harm the liver, cytotoxins attack cells, dermatoxins that irritate the skin, and neurotoxins attack the nervous system.
Microcystis, a species of cyanobacteria, produces the hepatoxin microcystin. Microsytin is most common cyanotoxin found in water and is responsible for most poisonings in organisms from algal blooms. . The Microsystis species can live in many different water conditions, including water with extremely varying temperatures and pH. The toxin is released into the water when the cells die or burst. Once the toxin-infested water is ingested, microcystin inhibits liver enzymes from maintaining structural support in the liver. This toxin mostly affects livestock and other wildlife that drink from water sources that have algal blooms. People can also be exposured to microcystin by either accidently swallowing lake/pond water with algal blooms or consuming contaminated produce from gardens that used lake water for gardening.
Anabeana is another species of blue green algae that produces two types of neurotoxins: anatoxin and saxitoxin. Anatoxin is an extremely potent toxic substance the cause death within minutes of exposure. It irreversibly binds to the acetylcholine receptor. The sodium channels of the cell are locked open, become over-stimulated and causes respiratory paralysis and death. Saxitoxin is similar to Anatoxin. It also interferes with sodium channels but blocks them, causing under-stimulation and slow respiratory paralysis. Both of these toxins are known to cause death in wildlife and livestock that drink infected water. There have also been cases of people experiencing numbness of the mouth and tongue after consuming mollusks or fish that contain small doses of the toxins.
Even though algae blooms do release toxins, not all blooms are harmful. A little less than 50% of blooms are harmless to human and wildlife health.
by Jason Zheng
There’s a silent growing epidemic of toxic algae blooms
across the U.S. which disrupts marine life, tourism and recreational
activities, and economy. Toxic algae blooms can occur from chemical runoff from
farms and other sources run into waterways, creating a thick, green, soup-like
film on the surface. It seems harmless, but these types of blooms greatly
impact the quality of human health and animal life. Harmful algae bloom can
release dangerous toxins that can sicken and even kill humans or animals. It
creates dead zones in water, raises water treatment cost for drinking water,
and even impact certain industries that depends on clean water.
Having direct exposure to toxic algae in consuming or
swimming in polluted water can lead to rashes, stomach or liver illness,
respiratory and neurological problems. Harmful blooms consumed by small fish
and shellfish, these toxins move up the food chain, impacting larger animals
and humans. Non-toxic blooms can also block sunlight and clog fish gills. The
presence of nitrates and algae blooms in drinking water raises the price of
water treatment costs. The tourism industry, primarily fishing and boating
activities, also takes a hit from these organisms. Toxic algae blooms can also
target the real estate industry. For states like Florida and California, clean
water can raise the value of a waterfront property up to 25%. According to the
2015 National Study of Realtors, the real estate industry accounted nearly $200
million or more than 20% of Florida’s Gross National Product.
The Environmental Working Group reported findings that since
2010, nearly 300 algae blooms have been recorded in lakes, rivers, and bays in
48 states. 169 toxic blooms were reported in 40 states in 2017, compared to
2010, there was only three blooms. Toxic algae blooms occur all year around,
but it is most during the summer months. Frequent changes to the weather can
also impact bloom yield.
Algae blooms occur naturally, but toxic algae blooms can be
linked to the agricultural system. Due to the constant run-off of farming
chemical and animal manure into waterways, chemicals—including phosphorus—can
accelerate the growth rate of algae. Farmers are often exempt from the Clean
Water Act and they receive billions of taxpayer dollar annually through federal
farm and insurance subsidies. It is more than fair to ask them to take
precautionary measure or additional steps to prevent these water pollutions
from happening. Even though some may not be affected by these blooms at that
time and moment, the toxic water that is being used to water livestock
production, will affect us. Taking precautionary measures, such as planning a
strip of grass next to stream and applying fertilizer in a precise manner, can
greatly decease water pollution from farms.