Toxin Producing Blue-Green Algae

Summary: FOBL is disseminating the following information as volunteers, with the understanding that we may be misinterpreting some of the information. However, we believe you will agree with us that the excerpts provided show:

The blue-green algae we have is toxic to the liver and can have other health effects.

Ingesting by swallowing water can be dangerous.

We are uncertain of how much one would have to ingest (one swallow or multiple swallows).

We do not have concentration levels at different locations on the lake to match up against recommended levels mentioned below.

Absorption through the nose or mouth while swimming, jumping off a trampoline or waterskiing can be dangerous. See the discussion of “Chapter 5" below.

Waterskiing and tubing is problematic because of risk of inhalation (so is sailing, especially if one were to tip and swallow water). Indeed, waterskiing may be just as dangerous as swimming. See the discussion of “Chapter 5" below.

Toxins are released when the digestion process works on the algae.

Toxins are released when the algae dies naturally, so the lake is toxic even after the bloom disappears.

Right now we don't know what that means in terms of levels or adverse health effects.

The algae is more dangerous for children.

The algae is dangerous to pets who drink it or go in the water and then lick their fur.

FOBL is a committee of lake residents. We are not microbiologists, physicians, or public health officials.

Please read all of this e-mail. The last excerpt, in particular, contains very important information about a serious risk of liver injury that would appear to apply to us.

1 From a long article at the following website:

http://www.who.int/water_sanitation_health/resourcesquality/toxcyanchap3.pdf;

Microcystis Botrys is one of a hepatotoxic algae, i.e., it is a liver toxin.

2. Excerpts from the Wisconsin DNR website:

http://dnr.wi.gov/org/land/parks/safety/bluegreenalgae.html

A. Blue-Green Algae (BGA) is a cyanobacteria. When environmental conditions are just right, blue-green algae can grow very quickly in number. Most species are buoyant and will float to the surface, where they form scum layers or floating mats. [I wonder whether "scum" can refer to the bubbles we have seen]

B. When a blue-green algae bloom dies off, the blue-green algae cells sink and are broken down by microbes.

C. Blue-green algal toxins are naturally produced chemical compounds that sometimes are produced inside the cells of certain species of blue-green algae. These chemicals are not produced all of the time and there is no easy way to tell when blue-green algae are producing them and when they are not. When the cells are broken open, the toxins may be released. Sometimes this occurs when the cells die off naturally and they break open as they sink and decay in a lake or pond. Cells may also be broken open when the water is treated with chemicals meant to kill algae, and when cells are swallowed and mixed with digestive acids in the stomachs of people or animals. The only way to be sure if the toxins are present is to have water samples analyzed in a laboratory using sophisticated equipment.

D. Should I get treat a blue-green algae bloom with a chemical to get rid of it

No. Treatment of surface water that is experiencing a blue-green algae bloom with an herbicide or algaecide may kill the blue-green algae, but any toxin(s) contained in the cells will be released at once, resulting in a slug of toxin(s) in the water. So while the bloom may no longer be visible, toxin(s) may be present for some period of time following treatment. It is best to stay out of a water experiencing a bloom and wait for the bloom to dissipate on its own.

E. Hepatotoxins—These toxins affect the liver and other internal organs, and can cause gastroenteritis, tissue damage, muscle weakness, paralysis, and respiratory failure (with acute exposure), tumors, and possibly liver cancer (with long-term, chronic exposure). Examples include microcystins and nodularins.

F. Are children more vulnerable than adults

Yes. Children may be at greater risk than adults for two primary reasons: Children love to play in the water, but typically do not understand the health risks as well as adults. As a result, they may drink the water because they are thirsty or swallow it accidentally while swimming.

Children weigh less, and so a smaller quantity of toxin may trigger an adverse effect.

G. Can blue-green algae make my pet sick

Animals are not necessarily more sensitive to blue-green algal toxins than humans. However, many animals, such as dogs and cattle, enjoy being in the water, even if there is an unsightly green scum layer floating on top. When such a bloom is present, animals may consume large quantities of blue-green algae if they drink the water, and if those blue-green algae happen to be producing toxin(s), the animals can become very ill, and even die. Symptoms of blue-green algal toxin poisoning may range from lethargy and loss of appetite to seizures, vomiting, and convulsions. Dogs are particularly susceptible to blue-green algal poisoning because scum can attach to their coats and be swallowed during self-cleaning. [There are articles online of dogs dying. Dogs can ingest a lot of algae when they lick their fur after coming out of the water]

H. Can water containing blue-green algae blooms be used for recreational activities

Because local health officials cannot easily determine when blue-green algal toxins are being produced, anyone considering recreation on or in the water should use common sense. Simply put, if a scum-layer or floating mat is present, do not recreate in or on that water. The chance for health effects is greater if you or your children participate in water-related activities such as swimming, wading, water or jet-skiing, or wind surfing. Try to find areas where a blue-green algae bloom is not present.

I. Measures You Can Take to Protect Yourself

Do not swim in water that looks like "pea soup", green or blue paint, or that has a scum layer or puffy blobs floating on the surface

Do not boat, water ski, etc. over such water (people can be exposed through inhalation)

Do not let children play with scum layers, even from shore

Do not let pets or livestock swim in, or drink, waters experiencing blue-green algae blooms

Do not treat surface waters that are experiencing blue-green algae blooms with any herbicide or algaecide-- toxins are released into the water when blue-green algae cells die

Always take a shower after coming into contact with any surface water (whether or not a blue-green algae bloom appears to be present; surface waters may contain other species of potentially harmful bacteria and viruses)

J. Measures You Can Take to Help Reduce Future Blue-Green Algae Blooms

Maintain native vegetation along shorelines as buffer areas

Minimize activities that result in erosion

Reduce the amount of fertilizer used on lawns

Use only phosphorus-free fertilizer when possible

Fix leaking septic systems

Use only phosphorus-free detergents in dishwashing machines

3. Excerpts from a Detailed Fact Sheet from the Humboldt County (California) Department of Health and Human Services

A. Blooms may persist for up to seven days but the resulting toxins may last for as long as three weeks.

[emphasis is in original; I interpret this to mean that when the algae die, the toxins are released and can be in the water for 3 weeks. Don't know if I am right; see also the last article cited below]

B. BGA moves up and down within the water column and thus may not always float to the surface

C. Blooms are most likely to occur when three conditions converge: (1) wind is quiet or mild, (2) water is warm but not hot (60-86 degrees) [this is a little different than what we have heard], and (3) water harbors an abundance of nutrients nitrogen and phosphorus

D. This article advises:

1. On reported dog deaths

2. Avoid wading or swimming in water where algae blooms are visible and avoid dense mates of algae. Closely supervise young children, as they are more at risk due to their small body size.

3. Do not drink, eat or handle the algae and avoid ingesting

4. Swimmers should shower and pets be rinsed immediately after bathing

5. Use water-resistant gloves to remove unwanted algae from shorelines

4. Excerpts from an article entitled "Toxin Producing Blue-Green Algae at recreational Sites in the St. Johns River, Florida

A. Currently [Article is dated April 3, 2006] no guidelines levels exist for the management (monitoring, testing, posting and/or closure) of surface waters for potentially toxic cyanobacteria and/or cyanotoxin content for water bodies that support recreational activities in the US. The World Health Organization, however, does suggest concentration levels for the increased monitoring and warning of recreational users that bloom conditions exist due to the increase in probability of human health risks. These levels are 20,000 cells/ml (aleet level 1) and 100,000 cells/ml (alert level 2), which is approximately equivalent to 2-4 µ/L [micrograms per liter] and 20 µ/L of microcsytin-LR, respectively [I don't know what L-R refers to]. Australia [which has a major problem with BGA in its lakes] has recently developed recreational guidelines for adults and children of 45 µ/L and 15 µ/L for total cyanotoxins, respectively.

B. MCs [microcystins] are a family of liver toxins and potentially can act as tumor producing agents.

5. Excerpts from article entitled "Assessing Potential Health Risks from Microcystin Toxins in Blue-Green Algae Dietary Supplements." [Apparently BGA is being sold as a dietary supplement][written May 2000 - 2 of the authors are from UW Department of Food Microbiology and Toxicology]

A. Because of the known hepatotoxic potency of microcystins, the presence of these toxins in food products is cause for concern. The toxicity of microcystins has been extensively studied. After ingestion, microcystins are actively taken into the portal circulation form the digestive tract and rapidily cleared from the plasma via active transport into hepatocytes. Once inside hepatocytes, microcystins tightly bind and inhibit protein phosphatase 1 and 2A (PP1 and PP2), resulting in the hyperphosphorylation of cellular proteins with critical roles in the maintenance of cellular structure and function. Acute exposure to high microcystin doses results in sevre damage to the hepatocytre cytoskeleton, causing morphologic changes in hepatocytes and sinusoids and, ultimately, intrahepatic hemorrhage and hypovolemic shock.

B. Although less is known about the possible health effects from exposure to lower doses of microcystins, there is increasing concern that chronic exposure to low levels may also pose a significant health risk. Potential tumor promotion is a primary concern. Microcystins are believed to promote tumor formation through the inhibition of PP1 and PP2A, which are integrally involved in cell-cycle regulation....Continuous low-level exposure to microcystins may also result in hepatic accumulation.. Studies have shown that, once taken up by the liver, microcystin excretion occurs very slowly. Bioaccumulation of microcystins have been demonstrated in laboratory animals and in aquatic vertebrates and invertebrates. These results raise concerns that long-term exposure to even very low levels of microcystins maye be significant and could ultimately result in liver cancer and other liver diseases.

[My comment is that this article is about use of BGA in dietary supplements; nevertheless, the article evidences the significant health concerns associated with exposure]

6. Chapter 3 of a book entitled Toxic Cyanobacteria in Water: a guide to their public health consequences, monitoring, and management:

A. 3.4.2. Chemical breakdown. In full sunlight, microcystins undergo slow photochemical breakdown and isomerisation, with the reaction rate being enhanced by the presence of water-soluble cell pigments, presumably phycobiliproteins. In the presence of pigments the photochemical breakdown of microcystin in full sunlight can take as little as two weeks for greater than 90 per cent breakdown, or logner than six weeks, depending on the concentration of pigment (and presumably toxin, although this has not been tested).

B. 3.4.3 Removal on natural sediments and soils. Microcystins appears to be retained only weakly on natural suspended solids in rivers and reservoirs; usually no more than 20 per cent of the total microcystin is absorbed...Cyanobacterial cells and microcystins were retained in soil columns, but less efficiently in sediment columns, in laboratory experiments simulating the fate of cyanobacterial toxins in artificial recharge of groundwater and bank infiltration.

C. 3.4.4 Biodegradation. In spite of their chemical stability and resistance to eucaryotic and many bacterial peptidases, microcystins are susceptible to breakdown by aquatic bacteria found naturally in rivers and reservoirs. These bacteria appear to be reasonably common and widespread...There is usually an initial lag phase with little loss of microcystin and this period can be as short as two days or more than three weeks, depending on the water body, climactic conditions, the concentration of dissolved microcystin and in some cases, although not all, the previous bloom history. Once the biodegradation process commences; removal of microcystin can be more than 90 per cent complete within 2-10 days. This may vary depending on the water body, initial microcystin and water temperature

7. Excerpts from “Chapter 5" - same book

A. 5.1.4 - Three potential routes of exposure to cyanotoxins can be distinguished: direct contact of exposed parts of the body, including sensitive areas such as eyes, ears, mouth and throat, and the areas covered by a bathing suit; accidental swallowing; and inhalation of water.

B. 5.1.4 - Incorporation of toxins through swallowing, contact with nasal mucosa, or inhalation are likely to be important routes of exposure during water-contact sports. Well documented evidence from one animal experiment and one case of multiple human illness indicates that inhalation and resorption through nasal and pharyngeal mucous membrances may present a high risk in water sports involving intensive submersion of the head (jumping from diving boards [Rave trampolines], sailboarding, canoe capsizing, competitive swimming) and inhalation of aerosols (water skiing). (emphasis added

C. Experimental results indicate a hazard of cumulative liver damage by repeated microcystin intake as can occur during a holiday with repeated daily bathing at a recreational site with high levels of microcystin-containing cyanobacteria. Sub-acute liver damage is likely to go unnoticed, because signs of liver damage are only apparent after severe damage. In addition, the dose-response curve for liver injury from microcystins is relatively steep. There may be little evidence of acute liver damage when levels are close to those that could lead to severe acute toxicity, and thus exposure at such levels is likely to be continued by people if they are uninformed of the risk (e.g., for consecutive days of a holiday or hot spell), thereby increasing the risk of cumulative liver damage.