Proceedings of Health Effects of Exposure to Cyanobacteria Toxins: 

State of the Science 

August 13-14, 2002 

A product of the collaborative efforts of the Florida Department of 

Health, the Center for Disease Control, Mote Marine Laboratory, the 

University of South Florida, and leading scientific contributors that 

presented at the conference. 

Editors: David Johnson, M.D., M.S., Raymond D. Harbison, Ph.D. 

1
Table of Contents 

 Page

Description of Monograph Paul C. Grivas, MPH 4 

Panel 1: Harmful Algal Blooms in Florida 

Moderator: Karen Steidinger, PhD 

Karen Steidinger, PhD Florida Fish/Wildlife Conservation 6 

Commission - Florida’s Harmful Algal 

Bloom Task Force: History and Focus 

John Burns, MS Cyanobacteria and Their Toxins in 16 

Florida Surface Waters 

Erin Bledsoe, MS University of Florida - The Distribution of 22 

Potentially Toxic Cyanobacteria in Florida 

Panel 2: National and International Perspective 

Moderator: Lora Fleming, MS, PhD 

Lorraine Backer, PhD, MPH Centers for Disease Control and Prevention– 37 

 A Brief Introduction 

Ian Falconer, DSc Australia’s Cyanobacteria Experience 40 

Michele Giddings, BSc Cyanobacteria Toxins: The Development 43 

and Evaluation of Methods to Determine 

Microcystin Levels in Canadian Water 

Supplies 

Anthony Lloyd, MS Blue-Green Algae and Their Toxins – 65 

Great Britain’s Perspective 

Ian Falconer, DSc WHO Guidelines (Summary) 73 

2
 Page 

Panel 3: Agency Activities 

Moderator: Bart Bibler, PE 

Wayne Carmichael, PhD Wright State University – Laboratory 74 

Methods for the Study of Harmful 

Cyanobacteria Waterblooms: “The CyanoHABs” 

James Evans, PhD Florida Department of Health – 86 

Cyanobacteria Toxins 

James Sinclair, PhD US Environmental Protection Agency – 89 

Current EPA Work on Algal Toxins in 

Drinking Water 

Richard Drew, MS Florida Department of Environmental 93 

Protection – Summary of FDEP 

Richard Clark, MS Florida Department of Health – DOH 97 

Aquatic Toxins Program

Bruce McLeod, MS Florida Manatee County – Summary of 100 

Water Treatment 

3
A Brief Introduction to: 

Health Effects of Exposure to Cyanobacteria Toxins: State of the Science 

by Paul C. Grivas, M.P.H. 

The conference entitled “Health Effects of Exposure to Cyanobacteria Toxins: State of 

the Science” took place on August 13th to the 14th, 2002 in Sarasota, Florida. The 

conference was sponsored by the Florida Department of Health (FDOH) in collaboration 

with the Centers for Disease Control and Prevention (CDC). Funding for the conference 

was provided, in part, through a Cooperative Agreement (U50/CCU415409-05-5 

Cooperative Agreement for Pfiesteria-Related Surveillance and Prevention). 

Cyanobacteria and their potential impact on human health is an emerging public health 

issue that has received increasing scientific interest resulting in new and ongoing 

research. While it has been substantiated that cyanobacteria produce toxins that are 

potentially capable of causing disease in humans, many questions remain unanswered 

regarding the identification and quantification of cyanobacteria and cyanotoxin in the 

environment and to what degree cyanobacteria found in the environment translates into 

risks to public health. 

The vision for this conference was to bring together leading scientists and public health 

officials involved with the emerging issues of cyanobacteria to share the latest 

information and research findings. The conference was a success in this regard in that 

participating presenters included state, national and international researchers and agencies 

involved with studying and addressing issues regarding cyanobacteria and their toxins. 

The presentations were organized into a framework consisting of three panels, the scope 

of each being specifically focused. The first and second panels took place on August 13, 

with a presentation at the Mote Marine Aquarium following the second session. The last 

panel, along with a tour of a water treatment facility in Manatee County, Florida, took

place on the 14th of August. 

The initial panel of the conference addressed the issues associated with cyanobacterial 

and other algal blooms in Florida. Dr. Karen Steidinger, who is the Task Force Chair of 

the Florida Fish and Wildlife Conservation Commission at the Florida Marine Research 

Institute, moderated this first panel. The focus of the second panel encompassed the 

national and international perspectives on cyanobacterial exposures. The moderator for 

this panel was Dr. Lora Fleming, from the University of Miami. Mr. Bart Bibler, a 

professional engineer, was the moderator of the third panel. This final panel addressed 

federal, state and local agency activities, primarily the laboratory testing of water 

supplies, associated with cyanobacteria. 

Dr. Alan Rowan and Dr. David Johnson, affiliated with the Florida Department of 

Health, organized and welcomed the attendees to the conference. They also outlined the 

schedule of events, including the order of presenters for the three panels. 

4
This monograph is a compilation of the presenter manuscripts, figures and related 

informational materials that represent the material presented at the conference. For one 

presentation, where the presenter did not provide a manuscript, a brief summary of the 

presentation is provided. 

The material information and opinions in this manuscript are those presented by the 

individual presenters and does not necessarily represent the position of the FDOH, CDC 

or the University of South Florida. Furthermore, the individual presentations have not 

been edited or endorsed by the FDOH, CDC, or the University of South Florida. 

Technical editing and formatting of the monograph was provided. The scientific content 

and opinions presented herein are those of the individual presenter. 

It is the intent that scientists, researchers, government agencies and others will use this 

monograph as a source of recent research findings and that it be available for those who 

were unable to attend the conference. 

Special thanks are due to Mote Marine Laboratory, Sarasota Florida for their assistance in 

planning and organizing the meeting facilities and to the University of South Florida for 

assistance in producing this manuscript. 

5
FLORIDA’S HARMFUL ALGAL BLOOM TASK FORCE: 

HISTORY AND FOCUS 

Karen A. Steidinger 

Florida Fish and Wildlife Conservation Commission 

Florida Marine Research Institute 

100 Eighth Avenue, S.E. 

St. Petersburg, FL 33701 

INTRODUCTION 

Harmful Algal Blooms or HABs occur worldwide in marine and freshwater environments 

from Norway to New Zealand (1,2). They can be defined as above background 

concentrations of aquatic nonvascular plants that have harmful effects on natural and 

human resources. Blooms can occur in the open ocean, bays and lagoons, and freshwater 

environments. Most of the harmful algae are microscopic and photosynthetic with plant 

pigments such as chlorophyll and accessory pigments. If the cell concentrations are high 

enough they can cause a visible discoloration of the water. 

Dinoflagellates, a group characterized by two whip-like flagella, comprise >70 percent of 

the known harmful microalgae. At least one toxic dinoflagellate is documented in the 

fossil record back 50 million years. There are >100 toxic HAB species worldwide. Most 

of these species produce potent toxins, e.g., neurotoxins, ichthyotoxins, hemolysins, 

cytotoxins, or reactive biocompounds. HABs that cause known public health impacts in 

marine waters, e.g., shellfish toxicity, are routinely monitored as part of programs to 

reduce or prevent human exposure (IOC, website, 3). 

In Florida, there are about 45 marine/estuarine and 15 freshwater toxic microalgae that

can or could cause animal mortalities, animal disease, and even human illness (4). In the 

marine environment, the organism that causes almost annual coastal impacts is a 

dinoflagellate known as Karenia brevis, a dinoflagellate that produces a potent 

neurotoxin. These events have been referred to as Florida red tide. 

Obviously, such living and human resource impacts result in economic impacts to local 

communities through reduced tourism and recreational activities, reduced work 

attendance, and the resultant loss of revenue. Marine and estuarine HABs affect coastal 

communities, but freshwater HABs can affect both inland and coastal communities 

because they can affect lakes, rivers, reservoirs and potable water supplies. In the case of 

cyanobacteria blooms, particularly in surface water supplies that are used for drinking 

water, toxins released into the water, if not removed, can cause mild to serious illness, 

even death. This has been documented for animals such as cows and dogs as well as 

humans (2,5). Human death from cyanotoxin exposure is rare but documented in unusual 

circumstances such as contaminated water for dialysis in Brazil or drinking directly from

a contaminated ditch in China. The cost of these HAB events, whether marine or 

freshwater, is not well characterized but can be in the millions and tens of millions USD 

per episode depending on the extent and duration of the event. In the 1970s, two red tide 

6
outbreaks caused by K. brevis affected several west coast counties for three to five 

months and caused an estimated 15 to 20 million-dollar USD impact to those counties

(4). Today, an economic report estimates that from 1987 to 1992 the average annual cost 

for US marine HABs was 49 million USD (in 2000 dollars, 6).

In October of 1997, the then Secretary of the Florida Department of Environmental 

Protection, Virginia Wetherall, created an Ad Hoc Task Force on Harmful Algal Blooms

with the then Secretary of the Florida Department of Health, Dr. James Howell, as ViceChairman. The Task Force was created to address harmful algal blooms in Florida 

waters, particularly red tides caused by Karenia brevis and potential fish kill/disease 

events caused by Pfiesteria piscicida. The concept for the Task Force followed a MidAtlantic States crisis with Pfiesteria fish kills and a major 1996 manatee mortality in 

Florida due to an uncommon winter-spring K. brevis red tide. These two events in 1996 

and 1997 provided the impetus for the task force. The Task Force originally consisted of 

> 50 representatives from state agencies, e.g., DEP, DOH, Game and Fresh Water Fish, 

water management districts, and the governor’s office, state and private universities, 

private laboratories, and interested parties. In 2000-2001, 35 members were reappointed 

and represented scientists, engineers, economists, citizens groups and government. The 

Task Force was originally charged with identifying existing information and data on 

HABs in Florida, identifying data gaps, and recommending how the data gaps could be 

filled by new research and monitoring programs. The Task Force created a 15 member 

Technical Advisory Group (TAG) to develop a review and make recommendations for 

the whole Task Force to consider and approve. The recommendations were made in 

March 1999 and presented to the HAB Task Force (4). These were approved by the Task 

Force and finalized in June 1999 and submitted to the Legislature by October 1, 1999, a 

requirement of Florida law. 

Until July of 1999, the Task Force was an ad hoc body. After the 1999 legislative session 

it became a legislatively created Task Force with a mandate, Ch. 370.06092, F.S. The 

Task Force had four specific tasks and serves as an advisory body to the Director of the 

Florida Marine Research Institute (FMRI): 1) determine the status and adequacy of 

existing information, 2) develop research and monitoring priorities including detection, 

prediction, mitigation, and control, 3) develop recommendations for government whereby 

they can create response/contingency plans fitting their specific needs and resources, and 

4) make recommendations to FMRI by October 1, 1999. Another statute (Ch. 370.06093, 

F.S.) authorized FMRI to implement a cooperative HAB program and spend authorized 

funds on specific marine and estuarine topics if State monies are appropriated or if 

federal and private grants are received. State funds were appropriated in fiscal years 

1998-1999 to 2000-2001 for Task Force activities. Between July 1998 and July 2001, the 

Task Force received three million dollars through the Florida Fish and Wildlife 

Conservation Commission’s Florida Marine Research Institute. In addition, Task Force 

projects received $270,000 from FMRI’s 2001-2002 appropriation. Each fiscal year, the 

appropriated monies were non-recurring which meant that each year the monies had to be 

requested in the agency’s budget request and lobbied for by the agency and private 

groups interested in Task Force priorities. Other State HAB monies during this time

period were appropriated for FMRI and Mote Marine Laboratory (MML), a private 

7
laboratory in Sarasota, Florida, through FMRI. All monies were directed toward the data 

gaps identified in the 1999 Task Force report or toward supplementing a federal grant 

awarded to Florida scientists called ECOHAB: Florida with FMRI as the coordinating 

entity. 

The March 1999 “white paper” on Harmful Algal Blooms in Florida was restricted to 

HABs that Task Force members identified as priorities, i.e., red tides caused by Karenia 

brevis, possible fish kills or disease events caused by Pfiesteria piscicida, ciguatera fish 

poisoning events due to Gambierdiscus toxicus and other ciguatera dinoflagellates, bluegreen algae or cyanobacteria blooms in freshwater and estuaries, potential tumor causing 

dinoflagellates such as Prorocentrum, and macroalgal blooms caused by Caulerpa, 

Codium, Gracilaria and other marine macrophytes. Although Florida has microalgal 

species that cause diarrheic shellfish poisoning and amnesic shellfish poisoning, no 

public health cases of these illnesses have been reported to date and therefore this is not a 

current problem although it still remains a potential problem. At the time of the 1999 

report, the Task Force considered red tides caused by K. brevis to be the most significant 

HAB factor to impact Florida in terms of natural resources, public health and economics 

because of its long history of neurotoxic shellfish poisoning cases, aerosol irritation to 

beachgoers, almost annual occurrences with thousands of square kilometers affected, and 

duration of blooms from one to 18 months. 

RED TIDE

Florida red tides, one type of HAB, result in mortalities of aquatic animals such as fish, 

birds or even marine mammals. Massive fish kills have been documented since the 

1800s off southwest Florida and were even mentioned in Spanish explorer diaries. 

Offshore reef fish or bottom fish, on the bottom or floating, were often the first 

causalities to be noticed by fishermen or divers. Beached dead fish present esoteric 

problems in a tourist based economy and offer a challenge for removal, particularly once 

red tide is transported into bays and lagoons. In addition to living natural resources, 

Florida red tides can impact humans in several ways. 

Some HABs can cause human illness or discomfort through consumption of toxic 

shellfish (1,2). Shellfish such as oysters, clams, mussels and other bivalves can filter out 

toxic microalgae as prey items and bioaccumulate the toxins. Humans in turn can 

become ill from toxic shellfish meats. In the case of Florida red tides, the human illness

from consumption of bivalves that have accumulated the toxin from K. brevis is called

Neurotoxic Shellfish Poisoning (NSP). With other toxic microalgae, the shellfish 

poisoning may have another name, like Paralytic Shellfish Poisoning. Each type of 

shellfish poisoning has different symptoms. Some cause death. Fortunately, NSP has not 

been associated with human fatalities. Florida red tides also produce a toxic aerosol that 

can irritate people’s eyes, nose, and throat if they are exposed to the aerosol at the beach 

or in an area where there is sea spray or a boat wake. Usually the respiratory effects 

disappear within several hours after leaving the beach or the exposure area. Respiratory 

irritation due to toxic particles airborne in sea spray is typical of some Karenia species 

8
and has been reported for a Trichodesmium bloom in Brazil (2). Otherwise, respiratory 

irritation is not commonly associated with HABs. 

The top eight Task Force priorities for red tide data and information (4) were 1) predict 

onset and movement of red tides in shelf waters, 2) develop rapid chemical assays to 

replace the mouse bioassay, 3) develop economic impact studies to evaluate losses by 

location or industry, 4) develop epidemiological studies to determine public health risks, 

5) investigate existing technologies for dead fish cleanup, 6) investigate applicability and 

efficacy of control and mitigation methods, 7) determine the fate and effect of toxins in

the marine environment, and 8) continue and enhance public information and outreach 

(4). Items 3) thru 6) and 8) were funded with State funds and items 1), 2) and 7) were 

funded with both federal and state funds. Since the initial funding sponsored by FMRI 

for Task Force initiatives, more federal funds have been made available for 

epidemiological and control studies through other sources. 

About one-half of all Task Force dollars were devoted to red tide projects. Additional 

state dollars for HAB research were appropriated for FMRI and MML red tide studies. 

Task Force red tide projects funded included: supplemental funds for ECOHAB: Florida 

cruises and research; economic impacts caused by red tides, development of new, rapid 

immuno-chemical assay for brevetoxins, occupational exposure to red tide aerosol and its 

effects, a red tides and public health literature review, and removal of floating dead fish 

at sea. In addition to targeted Task Force funded projects, FMRI funded a business 

outreach and information project that relied on the Red Tide Alliance and business 

community for input. The product of this venture can be seen at www.redtideonline.com. 

Solutions to Avoid Red Tide (START), a grassroots citizen group, conducted the project, 

which has been extremely successful. 

The legislative language that established the Task Force and its duties specifically 

mentioned the federal program called ECOHAB: Florida. This is a five-year federal, 

state, academic, and private laboratory partnership to study the development of Florida 

red tides and be able to predict their occurrence, movement, and landfall through coupled 

biophysical models. ECOHAB: Florida consists of 23 principal investigators from 13 

institutions in Florida, Michigan, Mississippi, North Carolina, South Carolina and New 

Jersey. The program is in the fifth and final year. Task Force funds were used to 

supplement ship time and analysis of data for the coupled physical-biological 3D model 

being developed by Drs. John Walsh and Bob Weisberg of the University of South 

Florida based on their own studies and those of other PIs. The backbone of the 

ECOHAB: Florida program consists of three sampling strategies to gather data to develop 

the model, i.e., monthly cruises onto the shelf in a closed hourglass configuration so that 

boundary conditions of a control volume of seawater could be identified (USF, Dr. 

Gabriel Vargo), a weekly transect out to 30 miles during red tide season and at other 

times as well (MML, Dr. Gary Kirkpatrick), and a process cruise of several weeks during 

red tides in 1998, 1999, 2000, 2001 and 2002 (collaborating PIs). 

9
Although the ECOHAB studies are not complete, it is obvious that physical processes of 

water movement and physical concentration at fronts as well as nutrients influences plant 

abundance both offshore and inshore. ECOHAB: Florida funded studies are evaluating 

physical processes and nutrients and their sources in relation to coastal red tides. 

Nutrients can be organic or inorganic, major such as nitrogen and phosphorus, minor 

such as the trace element iron, and come from very diverse sources, e.g., offshore 

upwelling, atmospheric deposition, and terrestrial river runoff and estuarine flux. 

Karenia brevis is light adapted, favored by colored dissolved organic matter near shore 

waters, and is able to utilize organic N which has many sources (Walsh and Vargo, pers. 

comm.). Different sources of nutrients coupled with phytoplankton growth strategies can 

influence what HABs occur when on the West Florida shelf. For example nitrate and

silicate favor diatom blooms as would be expected. 

One of the theories for why Florida has K. brevis blooms involves species adaptations 

and interactions in a physical and chemical matrix on the west Florida shelf. This theory 

can account for most of the large red tides off the west coast of Florida (7). The theory 

recognizes that Saharan dust contains iron and iron is deposited over the west coast 

during storm events when the dust is carried from South Africa across the Atlantic to the 

Gulf of Mexico (7,8). These dust events precede Trichodesmium blooms based on an 

analysis of the historical database. The Trichodesmium blooms precede K. brevis

blooms, which lag behind the cyanophyte blooms. Trichodesmium is an atmospheric 

nitrogen fixer but requires among other elements, iron for its enzymes. This cyanophyte 

or blue-green alga can occupy thousands of square kilometers of the Gulf of Mexico and 

can be very dense. The regenerated nutrients from these blooms, particularly regenerated 

nitrogen, could fuel large red tides, as could decomposing dead fish from fish kills. 

Phosphorus and its importance in Florida red tides are also being evaluated (Vargo, pers. 

comm.). 

In addition to providing ECOHAB support for cruises, analyses, and modeling, Task 

Force and other funds have supported the development of an ELISA technique for the 

detection of brevetoxins in seawater and shellfish (9). The end product of this test 

hopefully will be a rapid, accurate test kit that can replace the mouse bioassay which is 

the current public health standard used for NSP. Although there are many more red tide 

studies funded with state funds, particularly at FMRI and MML, one effort points out that 

gathering data is not enough. There has to be adequate storage, compatibility and 

retrieval of data. Accurate metadata are among the critical needs. The coastal oceans 

observing system for HABs in the Gulf of Mexico has the acronym HABSOS 

(www.ncdda.noaa.gov/habsos) and through a state-federal partnership it has the capacity 

to store, integrate, and layer red tide data from the Gulf states and provide information to 

the public and educators. The future of red tide and other HAB monitoring and 

forecasting in Florida and elsewhere is in automated instrumentation packages aboard 

various fixed and not fixed platforms such as buoys or underwater vehicles or even 

aboard satellites that transmit real time or near real time data to facilities that can package 

it for analyses. These monitoring networks will feed directly to data receiving and/or

management portals such as HABSOS. 

10
PFIESTERIA 

In 1997, the Mid-Atlantic States were faced with an environmental scare from a 

dinoflagellate that was associated with fish kills and fish lesions (10). The organism was 

called the “cell from hell” because it was reported to attack and kill fish. Although put 

with other HAB species, these dinoflagellates do not have their own chlorophyll like 

most other HAB species but they are capable of taking in pigmented organisms as prey. 

At first the only described species was P. piscicida meaning “fish killer”, later another 

species named P. shumwayae was discovered (11). Most recently this second species has 

been described from New Zealand, Australia, Norway, Japan and other locations (12,13). 

There are other Pfiesteria appearing dinoflagellates in estuarine and marine waters that 

have not been described yet, but may be in this complex. Today, it is recognized that 

Pfiesteria, particularly P. shumwayae is widely distributed and is being studied from the 

aspect of being ichthyotoxic to fish. Different studies yield different results, yet all 

indicate P. shumwayae can kill fish via one or another mechanisms (14, 15). In Pfiesteria

there are varying degrees of toxicity that are defined by whether they can be induced to 

kill fish; there are also nontoxic strains. Finding such species in water or sediment 

samples does not automatically mean that there is a problem since they are widely 

distributed. If the area has blooms of Pfiesteria and the strain is toxic, there could be a 

problem that is visualized in fish kills. On the other hand, Pfiesteria is often thought of 

as causing lesions in fish, particularly characteristic lesions near the caudal fin and the 

anal vent. Recent evidence suggests that a fungus causes the lesions, which can be a 

primary pathogen (16, 17). Studies at FMRI are looking at this pathogenetic pathway for 

induced lesions using the fungus Aphanomyces (Sosa and Landsberg, pers. comm.). 

The Task Force identified nine priorities for Pfiesteria and Pfiesteria-like species (4), 

five of which are: 1) determine occurrence and distribution of PLS (Pfiesteria-like 

species) in Florida, 2) develop molecular probes for identification and differentiation of

PLS in Florida, 3) develop molecular probes for detection of PLS toxins or bioactive 

compounds in natural waters, 4) determine if PLS isolates are toxic or produce bioactive 

compounds that affect fish, and 5) determine the distribution of PLS in relation to fish 

disease or fish kill “hot spots” and relationship to other environmental factors such as 

nutrients. Targeted funds for Task Force priorities were directed to 2) and 4). Probes 

were developed for cryptoperidiniopsoids and P. piscicida and bioactive compounds 

were detected in cryptoperidiniopsoid and in a PLS species known as “Lucy”. The latter 

produced a lipid-soluble ichthyotoxic substance. 

CIGUATERA 

Ciguatera is known as tropical fish poisoning or TFP. It is associated with the 

consumption of tropical fish usually from reef areas. It can also be associated with 

invertebrates such as gastropods. The symptoms are similar to neurotoxic shellfish 

poisoning however, there is a very low human mortality rate. There are over 175 known 

human symptoms from rashes to aching teeth to disorientation and paralysis (2). It is 

thought that more than one toxin is involved and that is what accounts for the multitude

11
of symptomology. It is projected that there are 900 cases per year in Dade County alone 

(4). 

The Task Force identified 10 priorities for ciguatera research (4), five of which were: 1) 

develop accurate and rapid tests to detect ciguatera toxins in fish, 2) expand the testing 

network to document occurrence and extent of ciguatoxic fish, 3) develop a better 

monitoring system for recording and documenting confirmed incidences of ciguatera 

poisoning, 4) increase awareness and training in the medical community for recognizing, 

documenting, and treating symptoms, and 5) determine the economic impacts, including 

loss of revenue and productivity due to illness and treatment. No ciguatera priorities 

were funded. Dr. Lora Fleming, a University of Miami epidemiologist/physician and a 

Task Force member, considers ciguatera a significant public health problem in Florida 

that deserves investigation and research support. 

TUMOR PROMOTING MICROALGAE 

Bioactive compounds in dinoflagellates and cyanobacteria have been associated with 

tumors in experimental animals (2). Since the causative organisms occur in Florida, the 

Task Force identified five priorities (4) for research on tumor promoting substances 

produced by HAB species: 1) explore potential role of biotoxins such as okadaic acid in 

tumor development in sea turtles, either for direct turmorigenic effects or as sublethal 

immunosuppressive factors, 2) determine fate and effects of toxins in food web, 3) 

conduct animal exposure studies to determine effects of specific tumor-promoting 

compounds, 4) isolate and maintain potentially toxic species for toxin or bioactive 

compound identification, and 5) include potential species of concern in any statewide 

survey. Number 5) is being addressed in event responses, but none of the priorities were 

funded for targeted Task Force funds. 

MACROALGAE 

Macroalgal blooms in Florida can be extensive whether they occur in bays and lagoons or 

on the shelf, east coast or west coast. These blooms have had significant impact by 

altering habitat and affecting trophic pathways. The Task Force identified eight priorities 

(4), four of which are listed here. 1) Survey Codium populations out to 300 ft. depth in 

area of known occurrence for spatial and temporal variability and determine sources of 

drift algae on the east coast. 2) Survey invertebrate herbivore populations and determine 

food sources and feeding rates. 3) Verify environmental regulators of growth, e.g., light, 

temperature, and nutrients. 4) Determine nutrient sources and if there is a lag in 

macroalgal growth influenced by nutrient source or storage. One project was funded to 

investigate the source of nitrogen for Codium and Caulerpa blooms on the southeast 

coast and map the distribution of bloom forming macroalgae. 

CYANOBACTERIA (BLUE-GREEN ALGAE) 

The Task Force identified cyanobacteria blooms in fresh and brackish water as an 

emerging HAB problem in Florida and elsewhere. Blooms occur in surface freshwaters 

12
that either are used for drinking water or are being considered for drinking water (Mr. 

John Burns and Dr. Chris Williams, pers. comm.). The six Task Force priorities (4) were 

1) determine the distribution of toxic and nontoxic strains, 2) develop epidemiological 

studies to determine public health risks, 3) develop economic impact studies to evaluate 

losses by location or industry, 4) determine the roles of nutrient enrichment and managed 

freshwater flow in blooms, 5) determine fate and effects of toxins in the food web, and 6) 

investigate control and mitigation methods. 

Examples of cyanobacteria projects funded with targeted Task Force funds were 

“Assessment of Cyanobacteria in Florida Lakes, Reservoirs, and Rivers”, “Cyanobacteria 

Automated Detection Workshop”, “Cylindrospermopsis Culture for Production of 

Cylindrospermopsin”, and “Cyanobacteria Public Health Issues: Education and 

Epidemiologic Study. Many of these Task Force projects will be discussed in this 

meeting. Some of the results that can be highlighted are 1) Microcystis, 

Cylindrospermopsis, and Anabaena occur state-wide, 2) microcystin, 

cylindrospermopsin, and anatoxin-A have been found in surface waters, 3) microcystins 

have been found in finished drinking water, and 4) no human health problems from

cyanotoxins in finished drinking water have been documented in Florida. 

In June 2001, the Task Force met to review interim progress of Task Force funded 

projects. At that meeting summaries prepared by the principal investigators were 

discussed and questions were raised about the projects. The following were some of the 

questions about the cyanobacteria projects. 

• “When will standards for toxins be available?” 

• “Can blooms be prevented or reduced?” 

• “What is the effectiveness of home filters on tap water for removing toxins if

present?” 

• “What is the lag time between the bloom and the spike at the water treatment plant?” 

• “What are effective water treatments for toxins in drinking water?” 

• “If toxins can be detected, can they be removed?” 

For FY 2000-2001 cyanobacterial project recommendations, either specific projects were 

recommended to be continued, e.g., surveys, epidemiology studies, and educational 

materials or new time sensitive projects, e.g., culture of Cylindrospermopsis for toxin 

standards and a workshop to discuss probes or sensors to detect cyanobacteria and 

quantify their toxins. The latter would be appropriate for natural waters as well as water 

treatment plants. The workshop entitled “Cyanotoxin Detection and Quantification and 

Instrumentation” laid out a plan for initial collaboration and approaches. It looked at 

instrumentation and packaging of the instrumentation for deployment into natural water 

bodies or installation in treatment plants. 

13
The three million dollars for Task Force projects to fill in data gaps was successful, but 

just as importantly, project results were used to leverage for additional funds and other 

phases of research. Additional funds were made available through other sources to 1)

promote chemical or cell assays to replace mouse bioassays, 2) investigate effects of red 

tide aerosol on humans, 3) investigate the possibility for cyanotoxins in drinking water,

4) promote automation of detection and quantitation methods for natural waters, 

aquaculture, and water treatment plants, 5) promote state monitoring programs, and 6) 

promote new HAB studies not considered in the first three rounds of Task Force funding 

by pursuing new grants. Lastly, the Research Contracts Review Committee of the Task 

Force recommended that two workshops be held, one to address treatment methods for 

blooms and cyanotoxins in drinking water and the other to address public health and 

cyanobacteria. The Florida Department of Environmental Protection held the first 

meeting recently and the second is this meeting you are attending today that is sponsored 

by the Florida Department of Health. These workshops and other Task Force 

deliberations will lay the groundwork for a remaining Task Force activity, that of 

proposing recommendations for state and local governments to consider in the 

development of their response/contingency plans. 

ACKNOWLEDGEMENTS 

Each Task Force member, including the Technical Advisory Group, is thanked for input 

into the preparation of the 1999 white paper. In addition, the Sarasota, Manatee, and 

Pinellas County legislative delegations are acknowledged for their support, particularly 

Senator McKay, Senator Carlton, and Representative Bradley. Senator Ken Pruitt is

especially thanked for his initial vision in recognizing that HABs are a statewide natural 

resource and public health issue. 

REFERENCES 

Steidinger, K. A. 2002. Red tides and other harmful algal blooms, p. 2685-2693. In G. 

Bitton (Ed.) The Encyclopedia of Environmental Microbiology. J. Wiley & Sons, New 

York. 

Landsberg, J. H. 2002. The effects of harmful algal blooms on aquatic organisms. Rev. 

Fish. Sci. 10:113-390. 

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Anderson, D. M., Hoagland, P., Kaoru, Y. and White, A. W. 2000. Estimated Annual 

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15
Cyanobacteria and their toxins in Florida Surface Waters 

John Burns

Chris Williams 

Andrew Chapman

Introduction

Cyanobacteria have likely been an important ecological component of aquatic systems in 

Florida for thousands of years. However, increased eutrophication (e.g., nutrient 

enrichment) of lakes, rivers, and estuaries has led to a growing trend in the incidence of 

cyanobacterial blooms and the production of toxic metabolites. Florida’s sub-tropical 

climate, prolonged drought, significant hydrologic modifications, and continued 

urbanization have also contributed to the increased occurrence of toxic cyanobacterial 

blooms. 

Toxic cyanobacterial blooms in Florida were first recorded by Wayne Carmichael (1992) 

in Lake Okeechobee (1987, 1989) and Lake Istokpoga (1988). Dead cattle, signs of 

poisoning in laboratory mice, and contact irritation were found associated with Anabaena

and Microcystis blooms. The toxin microcystin and an unidentified neurotoxin were 

attributed to the toxic effects found in Florida lake samples. Although toxic 

cyanobacterial blooms had become a major concern throughout the world, and the World 

Health Organization had set provisional guidelines for the consumption of microcystinLR (WHO 1998), little information on toxic cyanobacteria in Florida waters had been 

published since those first toxic events identified in 1992. Following formation of the 

Florida Harmful Algal Bloom Task Force (FHABTF) in 1997 (Steidinger et al. 1999), 

cyanobacteria were recognized as a group of potentially toxic species in Florida that had 

increased in distribution and abundance and possibly represented major threats to water 

quality, ecosystems, drinking water supplies, and public health. Moreover, the FHABTF 

found that the growing dependence on cyanobacterial bloom effected lakes and rivers for 

drinking water supply was a primary impetus for the evaluation of the distribution and 

potential toxicity of cyanobacterial blooms throughout the state (SJRWMD 2000). 

Methods 

During 1998, the FHABTF, Florida Marine Research Institute, and St. Johns River Water 

Management District initiated a collaborative study with the Florida Department of 

Health and Wright State University to identify potential cyanobacterial toxins in Florida’s 

lakes, rivers, reservoirs, and estuaries. Samples were collected and analyzed during 1999 

and extended through 2000 to increase the understanding of cyanobacterial toxins in 

waters currently utilized for drinking water or identified as a potential future drinking 

water source. 

Methods employed to identify alga taxa included microscopic examination and epifluorescence. Algal toxins were characterized and quantified by enzyme linked 

immunosorbant assay (ELISA), protein phosphatase inhibition assay (PPIA), HPLC-Fl, 

16
HPLC-UV, and LC/MS/MS. Mouse bioassays were used to characterize toxicity by 

intraperitoneal injection of freeze-dried sample extracts into ICR-Swiss male mice. 

Results & Discussion 

With the assistance of numerous state and local agencies in 1999, a total of 167 samples 

were collected throughout Florida, eighty-eight of these samples, representing 75 

individual water bodies, were found to contain cyanotoxins. Approximately 80% of the 

samples containing cyanotoxins were found to be lethal to mice following intraperitoneal 

injection. 

Seven genera of cyanobacteria were identified from water samples collected. Microcystis

(43.1%), Cylindrospermopsis (39.5%), and Anabaena (28.7%) were observed most 

frequently and in greatest concentration. Planktothrix (13.8%), Aphanizomenon (7.2%), 

Coelosphaerium (3.6%) and Lyngbya (1.2%) were found less frequently, but at times 

accounted for a significant proportion of the planktonic and macroalgal species 

composition. Aphanizomenon and Anabaenopsis were also found consistently during the 

2000 survey. Cyanobacterial blooms were common throughout the state, some of which 

formed continuous blooms in eutrophic and hypereutrophic systems. Many of the water 

bodies affected by cyanobacterial blooms were identified by water management agencies 

as areas of current concern or were being addressed by ongoing or proposed restoration 

efforts. 

Algal toxins identified from bloom material during the study included hepatotoxic 

microcystins, neurotoxic anatoxin-A, and the cytotoxic alkaloid cylindrospermopsin. 

Subsequent identification of lyngbyatoxin-A and debromoaplysiatoxin were found 

associated with Lyngbya wollei blooms collected from Florida springs. 

Microcystins were the most commonly found toxins in Florida waters, occurring in all 87 

samples analyzed during 1999. During the 2000 survey, microcystins were detected in 

pre- and post-treated drinking water. Finished water concentrations ranged from below 

detection levels to 12.5 μg L-1. Microcystins are considered the most frequently found 

cyanobacterial toxins around the world. Over 60 structural variants of this cyclic peptide 

have been reported, causing considerable concern due to their high chemical stability, 

high water solubility, environmental persistence and exposure to humans in surface water 

bodies. The World Health Organization has set a provisional consumption limit of 1 μg 

L-1 for microcystin-LR (WHO 1998). The mammalian toxicity of microcystin occurs by 

active transport across membrane boundaries and is mediated through binding to protein 

phosphatases (Runnegar et al. 1991; Falconer et al. 1992). Analysis of protein 

phosphatase inhibition activity, an index of microcystin bioactivity, was found to be 

positive in 44 (69%) of 64 Florida samples tested. There is limited evidence of tumor 

promotion (Sato et al. 1984; Falconer 1991, Nishiwaki-Matsushima et al. 1992, Wang 

and Zhu 1996) and clastogenic dose-related increases in chromosomal breakage by 

microcystin (Repavich et al. 1990), but no mutagenic evidence has been reported 

(Runnegar and Falconer 1982, Repavich et al. 1990). 

17
Anatoxin-a is a potent neurotoxic alkaloid that has been frequently implicated in animal 

and wildfowl poisonings (Ressom et al. 1994). It is considered a nicotinic agonist that 

binds to neuronal nicotinic acetylcholine receptors which leads to depolarization and a 

block of electrical transmission in the body (Soliakov et al. 1995). At sufficiently high 

doses (oral LD50 = >5,000 μg kg-1 body weight), it can lead to paralysis, asphyxiation, 

and death (Carmichael et al. 1975, Carmichael 1997). The authors have suggested that 

unexplained bird and alligator mortality events during cyanobacterial blooms in Florida 

lakes may be due to exposure to neurotoxic compounds produced by species of 

Anabaena, Aphanizomenon, and Cylindrospermopsis. Anatoxin-a was found in three 

finished water samples and in tissues from Blue Tilapia and one White Pelican during 

surveys in 2000. Anatoxin-A was found in the gut and liver of a White Pelican and in 

Blue Tilapia (0.51 to 43.3 μg g-1 ) and in finished drinking water (below detectable limits 

to 8.46 μg L-1). Preliminary evidence suggests that Cylindrospermopsis raciborskii

isolates from Florida lakes and rivers can produce anatoxin-a (Mark Aubel, CyanoLab; 

Wayne Carmichael, Wright State University). 

All 1999 samples containing the organism Cylindrospermopsis were positive for the 

toxin cylindrospermopsin. Nine (9) finished drinking water samples collected during the 

2000 survey were positive for cylindrospermopsin and ranged in concentration from 8.07 

to 97.12 μg L-1. Identification of the algal toxin cylindrospermopsin during this study 

represented the first record of this hepatotoxic alkaloid in North America. This toxin 

primarily affects the liver, but extracts given orally or injected in mice also induce 

pathological damage to kidneys, spleen, thymus, and heart (Hawkins et al. 1985, 1997). 

Cylindrospermopsin is a potential important contaminant of drinking waters in Australia, 

Central Europe, South America, and the United States. The toxin was identified after 138 

children and 10 adults were poisoned following a Cylindrospermopsis bloom and copper 

sulfate applications in a water supply reservoir on Palm Island, Australia (Hawkins et al. 

1985). Over 69% of the affected individuals required intravenous therapy for electrolyte 

imbalance, and the more severe cases for hypovolemic and acidotic shock (Byth 1980). 

The oral toxicity or lethal dose of cylindrospermopsin has been reported between 4.4 and 

6.9 mg kg-1 mouse body weight with death occurring 2-3 days after treatment (Humpage 

and Falconer 2002). In experiments where cell free extract of Cylindrospermopsis was 

administered to mice in drinking water over 90 days, no pathological symptoms were 

recorded up to a maximum dose of 150 mg kg-1 day-1 (Shaw et al. 2001). Humpage and 

Falconer (2002) suggest a Tolerable Daily Intake and Guideline Value for 

cylindrospermopsin in drinking water of 1 μg L-1 based on an oral No Observed Adverse 

Effect Level of 30-μg kg-1 day-1 and a Lowest Observed Adverse Effect Level of 60-μg

kg-1 day-1. 

Lyngbyatoxin-a and debromoaplysiatoxin have been identified from Lyngbya wollei and 

L. majuscula samples collected from Florida springs and marine embayments, 

respectively (J. Burns, N. Osborne, and G. Shaw, unpublished data). Concentrations 

have ranged from below detection to approximately 4.5 mg kg-1. The aplysiatoxins and 

lyngbyatoxins are considered dermatotoxic alkaloids, causing severe dermatitis among 

swimmers and other recreational users of water bodies that come into direct contact with 

the organism (Mynderse et al. 1977, Fujiki et al. 1990). Aplysiatoxins are lethal to mice 

18
at a minimum dose of 0.3 mg kg-1 (Moore 1977). Aplysiatoxins and lyngbyatoxins are 

also considered potent tumor promoters and protein kinase C activators (Fujiki et al. 

1990). Osborne et al. (2001) reviewed the human and ecological effects of Lyngbya 

majuscula blooms and reported acute contact dermatitis in Hawaii, Japan, and Australia. 

One potential death due to exposure via ingestion of turtle meat containing lyngbyatoxina was reported by Yasumoto (1998). Recent reports from Cambodia (December 2002) 

include 140 illnesses, 100 individuals hospitalized, and 3 deaths following consumption 

of marine turtle meat suspected to contain Lyngbya toxins (Helen Rogers, Centers for 

Disease Control & Prevention, Atlanta, GA). Severe dermatitis has also been reported in 

Florida following recreational activities in waters supporting Lyngbya wollei blooms in 

Florida’s springs (John Burns, Ian Stewart and G. Shaw, unpublished data). 

Summary 

The occurrence of toxic cyanobacterial blooms in Florida have become more prominent 

following increased growth, declining groundwater supplies, and identification of 

impaired surface waters as future drinking water sources. Cyanobacterial toxins have

been identified in source waters used for drinking water supply and in post-treated 

drinking water during algal bloom events. Algal toxin concentrations in post-treated 

drinking water have exceeded existing and proposed World Health Organization 

guidelines for the oral consumption of microcystin and cylindrospermopsin. Severe 

dermatitis has also been reported by swimmers in Florida springs where Lyngbya wollei

mats have expanded following significant increases in groundwater nitrate levels. 

This information should be useful in developing appropriate Total Maximum Daily 

Loads for impaired Florida waters that do not currently meet their designated use. It 

could also support further efforts to characterize potential ecological and human health 

risks due to toxic cyanobacterial blooms. Identification of algal toxins in finished 

drinking water and reports of severe skin irritation following contact with toxic 

cyanobacteria should be utilized for justification and implementation of increased 

monitoring of potentially toxic cyanobacterial blooms by surface water managers and 

water utilities. Epidemiological studies may also be required in Florida to assess 

potential human health risks due to algal toxin consumption at the tap and for those 

exposed to cyanotoxic blooms during recreational users of lakes, springs and rivers. 

References

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Carmichael, W. W. 1997. The cyanotoxins. Adv. Botan. Res. 27:211-256. 

Carmichael, W. 1992. A Status Report on Planktonic Cyanobacteria (blue-green algae) 

and their Toxins. EPA/600/R-92/079. 

Carmichael, W.W., D. Biggs, and P. Gorman. 1978. Toxicology and pharmacological 

action of Anabaena flos-aquae toxin. Science 187:542-544. 

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Falconer, I. R. 1991. Tumor promotion and liver injury caused by oral consumption of 

cyanobacteria. Environ. Toxicol. Water Qual., 6(2):177:184. 

Falconer, I.R., A. Choice, and W. Hosja. 1992. Toxicity of edible mussels (Mytilus 

edulis) growing naturally in an estuary during a water bloom of the blue-green alga 

Nodularia spumigena. J. Environ. Toxicol. Water Qual. 7, 119-123. 

Fujiki, H., M. Suganuma, M. Nakayasu, H. Hoshino, R.E. Moore, T. Sugimura. 1982. 

The third class of new tumor promoters, polyacetates (debromoaplysiatoxin and 

aplysiatoxin), can differentiate biological actions relevant to tumor promoters. Gann 

73:495-497. 

Fujiki, H., M. Suganuma, H. Suguri, S. Yoshizawa, K. Takagi, M. Nakayasu, M. Ojika, 

K. Yamada, T. Yasumoto, R.E. Moore, and T. Sugimura. 1990. New tumor promoters 

from marine natural products. In: S. Hall and G. Strichartz (eds.) Marine Toxins: Origin, 

Structure and Molecular Pharmacology, American Chemical Society, Washington D.C., 

pp. 232-240. 

Hawkins, P.R., M.T.C. Runnegar, A.R.B. Jackson, and I.R. Falconer. 1985. Severe 

hepatotoxicity caused by the tropical cyanobacterium (blue-green alga) 

Cylindrospermopsis raciborskii (Woloszynska) Seenaya and Subba Raju isolated from a 

domestic water supply reservoir. Appl. Environ. Microbiol. 50(5):1292-1295. 

Hawkins, P.R., N.R., Chandrasena, G.J. Jones, A.R. Humpage, and I.R. Falconer. 

Isolation and toxicity of Cylindrospermopsis raciborskii from an ornamental lake. 

Toxicon 35:341-346. 

Humpage, A. R. and I. R. Falconer. 2002. Oral Toxicity of Cylindrospermopsin: No 

Observed Adverse Effect Level Determination in Male Swiss Albino Mice. Cooperative 

Research Center for Water Quality and Treatment, Salisbury, South Australia, Australia. 

Moore, R.E. 1977. Toxins from blue-green algae. Bioscien. 27:797-802. 

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the Oscillatoriaceae: isolation of debromoaplysiatoxin from Lyngbya. Science 196:538-

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Ishikawa, W.W. Carmichael, and H. Fujiki. 1992. Liver tumor promotion by the 

cyanobacterial cyclic peptide toxin microcystin LR. J. Cancer Res. Clin. Oncol. 

118(6):420-424. 

Osborne, N.T., P. Webb, and G.R. Shaw. 2001. The toxins of Lyngbya majuscula and 

their human and ecological health effects. Environment International 27:381-392. 

20
Repavich, W.M., W.C. Sonzogni, J.H. Standridge, R.E. Wedepohl, and L.F. Meisner. 

1990. Cyanobacteria (blue-green algae) in Wisconsin waters: acute and chronic toxicity. 

Water Res. 24(2):225-231. 

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Maynard and I. Falconer. 1994. Health Effects of Toxic Cyanobacteria (Blue-Green 

Algae). Australian National Health and Medical Research Council, Looking Glass Press. 

Runnegar, M.T.C. and I.R. Falconer. 1982. The in vivo and in vitro biological effects of 

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cyanobacterial hepatotoxin microcystin by isolated rat hepatocytes. Toxicon 29(1):43-51. 

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placental form of glutathione S-transferase as a new marker protein for preneoplasia in 

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H} dopamine 

release from rat striatal synaptosomes. Neuropharmacology 34(11):1535-1541. 

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21
The Distribution of Potentially Toxic Cyanobacteria in Florida 

Edward J. Phlips 

Erin Bledsoe 

Mary Cichra 

Susan Badylak 

Jessica Frost 

Department of Fisheries and Aquatic Sciences 

University of Florida 

Gainesville, Florida 

The cyanobacteria, or blue-green algae, are the oldest group of algae on earth, dating 

back over 3 billion years, and are still one of the most widespread and abundant forms of 

photosynthetic organisms. The fact that a number of species in the group not only form 

blooms but also produce powerful toxins, places them into a position of particular human 

interest and concern. This concern is particularly acute in Florida, which is exceptionally 

blessed with an abundance of aquatic natural resources. There is perhaps no other state in 

the continental United States where the quality of life and economy is more closely tied 

to the integrity and sustainability of these resources. There is no doubt that the issue of

potentially toxic cyanobacteria blooms deserves the attention of researchers and 

managers throughout the state. In this paper we examine this issue from the perspective 

of our research activities around the state over the past twenty years. During this time we 

have carried out long-term studies of planktonic algae populations in three major marine 

ecosystems (Florida Bay, Indian River Lagoon and the Suwannee Estuary) and five major 

freshwater ecosystems (Lake Okeechobee, the St. Johns River, Lake Griffin, the Rainbow 

River and the Suwannee River)(Figure 1). Despite the broad range of environmental 

conditions represented by these seven ecosystems, cyanobacteria play an important role 

in the structure and function of all seven. There are a number of factors that play a 

prominent role in the control of algal blooms in many of these ecosystems, including 

trophic state, water exchange rates, light availability and growth-limiting nutrients status. 

Algal Blooms and Trophic Status 

Many of Florida’s lakes and rivers have an ample supply of nutrients to sustain high 

levels of phytoplankton biomass. In water management and limnological circles such 

lakes are called eutrophic, Greek for ‘well-fed’. One of the common public 

misconceptions is that eutrophic conditions are a certain sign of the influence of human 

activity. Actually, eutrophic lakes and rivers can arise naturally due to accumulation of 

organic matter over time or edaphic factors, like surface or ground water input from

naturally nutrient-rich sediments. These phenomena, in part, explain the high frequency 

of eutrophic lakes in certain regions of central Florida, where phosphorus-rich sediments 

are widespread, as indicated by the phosphate mining activities in the region. This does 

not imply that humans do not play a major role in promoting algal blooms. There is 

substantial evidence that the explosion of human development in Florida over the past 

century has elevated the trophic status of many lakes and rivers, in some cases 

dramatically. With this elevation in trophic status, the frequency and intensity of algal 

22
blooms has increased. In Florida, cyanobacteria have been exceptionally successful in 

taking advantage of the increase in bloom potential (Canfield et al. 1989). 

The Distribution of Potentially Toxic Algae in Florida 

For most lakes and rivers in Florida, historical records of algal composition are absent or 

very sparse, making it almost impossible to define the distribution of potentially toxic 

algae species in past years. Even where significant data sets are present, information on 

the toxicity of algal species is largely absent. Therefore, in most cases it is only possible 

to discuss the distribution of ‘potentially’ toxic algae species, which currently includes 

the species listed in Table 1. The five cyanobacterial genera (groups) that contain the 

freshwater species of greatest concern are Microcystis, Oscillatoria, Anabaena, 

Cylindrospermopsis and Aphanizomenon. There are also groups of cyanobacteria that 

form blooms, but whose toxicity is not as well established, like Lyngbya and the widely 

occurring marine species Synechococcus. 

Since the greatest risk associated with cyanobacterial toxins is found under bloom

conditions, it is obvious that eutrophic and hypereutrophic lakes, rivers and coastal 

ecosystems are the focus of much attention. As expected, recent surveys of Florida 

indicate that cyanobacteria are common features of ecosystems that exhibit elevated 

trophic status (Canfield et al. 1989). Even in lakes, rivers and estuaries subject to high 

levels of nutrient loading, the expression of that nutrient availability in the form of algal 

bloom can be effected by other factors, like residence time, light limitation or biomass 

loss through grazing, senescence or disease. The influence of these factors is manifested 

in our observations of the seven aforementioned ecosystems. 

Lakes 

Lake Okeechobee, Florida’s biggest lake and the second largest lake in the continental 

United States, has been the site of some of the most widely publicized algal blooms in the 

country. Since intensive monitoring of the lake began in the 1970’s, blooms of the 

cyanobacteria Microcystis, Anabaena, Oscillatoria and Cylindrospermopsis have been 

observed on numerous occasions, in many cases covering over 100 square miles of the 

lake. Most of the largest blooms have been confined to a crescent-shaped region along 

the western side of the lake. The center and eastern part of the lake generally contain 

relatively low algal standing crops, due in large part to the low light availability caused 

by the re-suspension of muddy flocculent sediments (Phlips et al. 1995, 1997). These 

observations demonstrate that the distribution of potentially toxic algal species in 

structurally complex ecosystems, like Lake Okeechobee, may not be uniform (Phlips et 

al. 1993). Cyanobacteria blooms in Lake Okeechobee also exhibit significant temporal 

variation. The intensity and composition of blooms vary on both intra- and inter-annual 

time scales (Figure 2), reflecting changes in lake stage, nutrient limitation and nutrient 

loading (Phlips et al. 1997). 

In contrast to the spatial and temporal heterogeneity of blooms in Lake Okeechobee, in 

some lakes, blooms of key species can persist for extended periods of time. For example, 

23
bloom concentrations of Cylindrospermopsis in the hypereutrophic Lake Griffin have 

been observed to extend over the entire lake for periods in excess of a year (Figure 3). 

The ability of algae blooms to persist for long periods of time in Florida is in part 

attributable to the sub-tropical climate experienced over the peninsula, which diminishes 

the seasonality of blooms so often seen in temperate latitudes. This does not mean that 

temporal variations of climate are not important in Florida. Recent drought and flood 

periods have had a dramatic impact on the ecology of Florida’s aquatic environments. In 

Lake Griffin, drought periods have been characterized by low water turnover rates and 

elevated algal standing crops. Conversely, flood periods, like the El Nino of 1997/98, can 

reduce phytoplankton concentrations for periods of time by increasing the rate water 

turnover and dilution of biomass. This is a feature shared by many lakes in Florida, 

which are often characterized by shallow depths and low water volume. 

From a broader geographic perspective, there are few regions of Florida where blooms of 

the major species of algae outlined above cannot be found in a multitude of nutrient-rich 

lakes. While some regions of Florida have a higher proportion of eutrophic and 

hypereutrophic lakes and rivers than others, recent monitoring of over almost a 1000 

Florida lakes indicates that about half are subject to at least periodic algal blooms, if 

defined as chlorophyll a concentrations exceeding 40 μg / liter (Lakewatch, 2003). There 

are also factors other than trophic status that encourage the predominance of 

cyanobacteria over other algal groups in Florida. For example, Anabaena, 

Cylindrospermopsis and Aphanizomenon all fall into a select category of photosynthetic 

organisms that can convert biologically unusable elemental nitrogen (which comprises 

80% of the air) into the plant nutrient ammonia through a process known as nitrogen 

fixation. Since the growth of algae in many of Florida’s lakes and rivers is periodically 

limited by the supply of nitrogen fertilizer (like ammonia) the ability of these organisms 

to carry out nitrogen fixation places them at a distinct selective advantage over all other 

algae and plants, which are incapable of fixing nitrogen. 

Another example of an advantageous feature shared by Microcystis, Oscillatoria, 

Anabaena, Cylindrospermopsis and Aphanizomenon is buoyancy regulation. Unlike 

many species of algae that depend on mixing energy to stay afloat, these five 

cyanobacteria can adjust their position in the water column by inflating or deflating gas 

chambers in their cells. This ability is a great advantage in highly productive lakes and 

rivers where light available for photosynthesis can be restricted to only the top portion of 

the water column. This attribute also explains why blooms of the aforementioned 

cyanobacteria are often observed as the dreaded surface scum. 

Rivers 

Many of Florida’s rivers are characterized by high nutrient levels, due to both natural and 

anthropogenic factors. However, these high nutrient levels do not always lead to 

planktonic algae blooms. Most often, this is due to the impact of short residence time. 

The Suwannee and Rainbow Rivers are good examples of the latter phenomenon. While 

both rivers contain sufficient concentrations of both nitrogen and phosphorus to sustain 

bloom concentrations of planktonic algae, neither does, due to the fact that water seldom

24
stays in either system for more than a few days, preventing the accumulation of 

planktonic biomass. 

The Suwannee River is a blackwater river, which originates in the Okeefenokee Swamp 

in southeastern Georgia before winding southward 394 km to the Gulf of Mexico. The 

Suwannee River, with its tributaries the Alapaha, Withlacoochee, and Santa Fe Rivers, 

drains 28,500 km2

 of southern Georgia and north-central Florida. Phosphorus-rich 

freshwater inflow from the upper portions of the watershed are augmented by substantial 

nitrogen-rich groundwater contributions from numerous springs along the riverbanks, 

giving the river the second highest mean annual discharge of any river in Florida. 

Despite these high nutrient levels, their impact is not generally realized as plankton 

production within the river (Bledsoe and Phlips 2000), although accumulations of benthic 

cyanobacteria, like the potentially toxic Lyngbya, can occur, particularly when the 

normally highly colored river water becomes clearer due to drought conditions in the 

watershed. In the case of the Rainbow River, the shallow depths and crystal clear water 

provide the light necessary to support large populations of the potentially harmful benthic 

cyanobacterium, Lyngbya (Phlips 1999). Blooms of Lyngbya have become a 

management issue in a number of Florida’s river systems, like Crystal River. 

In contrast to the high flow environments of the Suwannee and Rainbow Rivers, there are 

rivers in Florida whose gentle slope results in very low flow rates and sufficient residence 

time to sustain planktonic algae blooms. Most prominent among these is the St. Johns 

River, which during drought years can actually flow backwards for significant periods of 

time due to tidal forces. Cyanobacteria blooms in the St. Johns River can be both 

extensive and intensive; reaching chlorophyll a concentrations in excess of 100 μg / liter 

(Phlips et al. 2000). Blooms of all five of the potentially toxic algae groups outlined 

above have been observed in the river (Cichra and Phlips 2002). Sometimes these 

blooms follow a recurring pattern. For example, blooms of Cylindrospermopsis and 

Anabaena in the St. Johns River occur in the summer, although the intensity of blooms

can vary from year to year (Figure 4). In contrast, blooms of Microcystis in the same

river are less predictable, occurring at any time during the year. 

Estuaries 

The estuaries of Florida are often the recipients of the nutrient loading experienced in

their respective watersheds. Therefore, the impact of human development on land is by 

no means restricted to freshwater ecosystems. By the same token, the impact of human 

development on coastal ecosystems extends beyond just the issue of nutrient loading. In 

restricted coastal ecosystems like Florida Bay and the Indian River Lagoon, changes in 

water flow patterns can have as dramatic an effect on the dynamics of algal blooms as 

changes in nutrient loading. 

In Florida Bay, a 1600 km2

 inner-shelf lagoon located just south of the Everglades and 

west of the Florida Keys, a network of very shallow mud banks located throughout the 

Bay restrict water exchange between inner regions of the bay and the Atlantic Ocean and 

Gulf of Mexico. One of the dominant features of phytoplankton communities in Florida 

25
Bay is the potentially harmful picoplanktonic cyanobacterium Synechococcus, which 

frequently reaches cell densities in excess of 106

 cells / ml in parts of the bay (Phlips et 

al. 1999). The relative dominance of Synechococcus during bloom events in Florida Bay 

is manifested by temporal patterns of phytoplankton biovolume at four sampling sites 

(Figure 5) representative of ecologically distinct regions in the bay (Phlips et al. 1995b). 

The north central region of Florida Bay is the focal point for blooms of Synechococcus, 

which spread south during the fall and winter due to shifts in wind direction. The 

physical restriction of tidal water exchange between the interior of the bay and the 

surrounding oceanic environment contribute to the build up of cyanobacterial standing 

crop by lowering the rates of water turnover. Prior to human development, surface water 

in South Florida flowed from Lake Okeechobee down through the Everglades and into 

Florida Bay. Extensive development of South Florida has restricted this flow and 

exacerbated the conditions favorable for algal blooms in the bay. 

In another one of Florida’s largest flow restricted estuaries, the Indian River Lagoon, the 

picoplanktonic cyanobacterium Synechococcus is once again a prominent component of 

planktonic algae blooms (Phlips and Badylak 2002). Although dinoflagellates and 

diatoms are the dominant bloom-forming groups in the lagoon overall, numerous 

cyanobacterial blooms, dominated by Synechococcus, have been observed in the most 

flow-restricted portions of the lagoon, like the Banana River region (Figure 6). Bloom 

levels of another cyanobacteria genus known to contain toxic species, i.e. Oscillatoria, 

have also been observed in the lagoon. The latter events appear to be associated with 

periods of high rainfall and may be indicative of washout of freshwater algae into the 

lagoon, rather than in situ, production (Phlips, unpublished data). 

On the west coast of Florida there are a number of major river discharges that contain 

high concentrations of nutrients. These include the two rivers with the highest freshwater 

discharge in Florida, the Apalachicola and the Suwannee Rivers, both of which flow into 

the area of Florida known as the Big Bend. The Big Bend is noted as one of the most 

productive areas of Florida’s coastline and certainly the nutrient discharged by these 

rivers contributes to that productivity. There is, however, concern that continued 

escalation of nutrient levels due to anthropogenic activities may soon create serious 

environmental problems, similar to those experienced in the Mississippi delta, like 

hypoxia and seagrass die-off. In the estuarine region of the Suwannee River, blooms of 

planktonic algae are common and are most often dominated by diatoms and 

dinoflagellates (Bledsoe and Phlips 2000, 2003). There are, however, periods in which 

small spherical cyanobacteria dominate the plankton community and on occasion reach 

bloom proportions. Blooms of these species are most common during the summer, 

particularly during periods of low freshwater outflow (Figure 7). The potential toxicity 

of these species is not known. 

Control of Potentially Toxic Algae Blooms 

The ideal long-term strategy for dealing with toxic algae is to prevent or reduce the 

occurrence of blooms. The most fundamental way of addressing this challenge is to 

reduce the availability of nutrients that support the growth of algae. There are lakes, 

26
rivers and estuaries in Florida where such water management efforts have or could be 

used to achieve this goal. The restoration of lakes, rivers and their watersheds is a major 

on going activity in many regions of Florida. The reduction of nutrient availability has 

been pursued in several different ways, including the control of external nutrient loading 

from the watershed and the binding or removal of nutrients within a system using 

chemical treatment (e.g. alum) or sediment removal (e.g. dredging) (Cooke et al. 1993). 

In terms of ecosystems subject to high levels of external nutrient loading, long-term

improvements of conditions generally require a strategy for the reduction of external 

load. 

There are of course ecosystems where it may be impractical, too expensive or 

fundamentally impossible to eliminate the occurrence of potentially toxic algae blooms. 

In such cases it may be necessary to carefully weigh the risk associated with certain 

activities in the system and make appropriate use recommendations or requirements. 

Unfortunately, there is currently insufficient information for most systems to make a 

meaningful risk determination at the present time. To make such a determination a 

number of important pieces of information about individual lakes and rivers need to be 

available to water managers, including: (1) the distribution of potentially toxic algal 

species in time and space (i.e. temporal and spatial patterns), (2) the potential impact of 

future changes in the character of the ecosystem and its watershed on algal communities, 

(3) the amount and relative strength of the specific toxins associated with blooms of the 

strains of potentially toxic algae species present in the ecosystem in question and (4) the 

pathways and mechanisms by which critical biological elements of the ecosystem,

including humans, may be exposed to, accumulate or pass-on toxins to other organisms. 

It is well known that different strains of potentially toxic algae species can vary in 

toxicity. Some of this variation is due to genetic differences between populations of 

algae, some of the variation is due to the impact of environmental variables (e.g. 

temperature, light, nutrient levels) and some of the variation is due to the life cycle of the 

algae (e.g. young versus old blooms). Therefore, determining the risk associated with 

algal toxins in individual lakes, rivers or estuaries require a well-designed and 

implemented monitoring program that can be used to gather essential information. 

For short-term remediation of problems with algal blooms in smaller systems, including 

man-made ponds, traditional algaecide applications, like copper-based products, have 

been employed for control. Unfortunately, such applications can worsen the problem by 

accelerating the release of toxins stored inside algal cells. In dealing with toxic algae 

blooms it may be necessary to employ an alternative approach that removes algae from 

the water column without killing the cells. Research is underway to explore alternative 

methods for treating blooms, like flocculation. Overall, post-bloom treatment is an 

expensive alternative. In situations where surface water is used for human consumption, 

such expense may be acceptable and a number of water treatment technologies for 

eliminating toxicity are in the process of development (Chorus and Bartram 1999). 

27
References: 

Badylak, S. and E.J. Phlips. 2002. Spatial and temporal patterns of phytoplankton 

composition and abundance in the Indian River Lagoon. J. Phycology. In 

preparation for submission. 

Bledsoe, E. L. and E. J. Phlips. 2003. The relationship between phytoplankton biomass, 

nutrient loading, and hydrodynamics in an inner-shelf estuary. Ophelia. In 

review. 

Bledsoe, E.L. and E.J. Phlips. 2003. The Consequences of Suwannee River Eutrophication for the 

Dynamics of Algae in the River and Associated Estuary. Ophelia. In review. 

Canfield, D.E., E.J. Phlips and C. Duarte. 1989. Factors influencing the abundance of blue-green 

algae in Florida lakes. Canadian J. Fisheries Aquatic Sci. 46: 1232-1237. 

Chorus, I. and J. Bartram. 1999. Toxic Cyanobacteria in Water: A guide to their public 

health consequences, monitoring and management. E & FN Spoon, London. 

Cichra, M., S. Badylak, N. Henderson, B. H. Rueter and E. J. Phlips. 1995. 

Phytoplankton community structure in the open water zone of a shallow subtropical lake (Lake Okeechobee, Florida). Arch. Hydrobiol. Beih. Ergebn. 

 Limnol. 45:157-175. 

Cichra, M. and E.J. Phlips. 2002. Phytoplankton communities of the Lower St. Johns River. J. 

Plankton Research. In preparation for submission. 

Cooke, G. D., E. B. Welch, S. A. Petersen and P. R. Newroth. 1993. Restoration and 

 Management of Lakes and Reservoirs, 2nd Edition. Lewis Publishers. 

Phlips, E.J. 1999. Lyngbya blooms in the Rainbow River. Final Report to the Southwest 

Florida Water Management District, Tampa, Florida. 

Phlips, E. J. 2002. Eutrophication and algae. In G. Bitton (Ed.), Encyclopedia of 

Environmental Microbiology. John Wiley & Sons, New York. 

Phlips, E.J., F. J. Aldridge, P. Hansen, P.V. Zimba, J. Ihnat, M. Conroy and P. 

 Ritter.1993. Spatial and temporal variability of trophic state parameters in a 

 shallow subtropical lake (Lake Okeechobee, Florida, USA). Arch. Hydrobiol., 

 128:437-458. 

Phlips, E. J., F. J. Aldridge, C. L. Schelske and T. L. Crisman. 1995. Relationship 

between light availability, chlorophyll a and tripton in a large shallow sub-tropical

lake. Limnol. Oceanogr. 40:416-421. 

28
Phlips, E. J., T. C. Lynch and S. Badylak. 1995b. Chlorophyll a, tripton, color and light 

availability in a shallow tropical inner shelf lagoon, Florida Bay. Marine Ecology 

Progress Series 127:223-234. 

Phlips, E. J., M. Cichra, K. Havens, C. Hanlon, S. Badylak, B. Rueter and P. Hansen. 

1997. Light versus nutrient limitation of phytoplankton abundance and structure 

in a shallow subtropical lake. J. Plankton Research. 19:319-342. 

Phlips, E. J., S. Badylak and T. C. Lynch. 1999. Blooms of the picoplanktonic 

cyanobacterium Synechococcus in Florida Bay. Limnology and Oceanography 

 44:1166-1175. 

Phlips, E. J., M. Cichra, F. J. Aldridge, J. Hendrickson, J. Jembeck and R. Brody. 2000. 

Light availability and variations in phytoplankton standing crops in a nutrient-rich 

blackwater river. Limnology and Oceanography 45:916-929.

Phlips, E. J., S. Badylak and T. Grosskopf. 2002. Factors affecting the abundance and 

composition of phytoplankton in a restricted subtropical lagoon. Coastal, 

Estuarine and Shelf Science, In Press.

Phlips, E.J., M. Cichra and J. Frost. 2002b. Algae blooms in Lake Griffin. Final Report 

to the St. Johns River Water Management District, Palatka, Florida. 

29
Table 1. Major groups of toxins, their primary site of action and the algae groups that 

contain species and strains capable of producing the toxins. Underline indicates the 

group(s) it is most commonly associated with. Note that the potential for toxin 

production is restricted to certain strains within the algal groups and can vary depending 

on environmental conditions (After Chorus and Bartram 1999). 

Toxin Site of Action Algal Group 

Microcystin Hepatotoxin – liver damage Microcystis, Anabaena, 

 Planktothrix (Oscillatoria), 

 Hapalosiphon, Anabaenopsis 

 Nostoc

Cylindrospermopsin Hepatotoxin – liver and other Cylindrospermopsis, 

 associated organs Aphanizomenon

Nodularin Hepatotoxin – liver Nodularia

Lyngbyatoxin Dermatoxin – skin and GI-tract Lyngbya

Aplysiatoxin Dermatoxin – skin Lyngbya

Anatoxin Neurotoxin – nerve synapse Anabaena, Aphanizomenon, 

 Planktothrix (Oscillatoria)

Saxitoxin Neurotoxin – nerve axons Anabaena, Aphanizomenon, 

 Lyngbya, Cylindrospermopsis

Suwannee River

St. Johns River

Lake 

Okeechobee

Lake Griffin

Indian River 

Lagoon

Florida Bay

Rainbow River

Figure 1. Long-term study of planktonic algae was conducted on three major marine 

systems (Florida Bay, Indian River Lagoon and Suwannee River Estuary) and five major 

30
freshwater ecosystems (Lake Okeechobee, the St. Johns River, Lake Griffin, Rainbow 

River and the Suwannee River) in Florida. 

igure2. The spatial and temporal distribution of cyanobacteria biomass (million μm3 F / 

ml) during a high lake stage year (first number)(1988-1989) and a low lake stage year

(second number)(1989-1990)(Cichra et al. 1995). 

31
0

5

10

15

20

25

7/1/2000

8/30/2000

10/29/200012/28/2000

2/26/20014/27/20016/26/20018/25/2001

10/24/200112/23/2001

2/21/20024/22/2002

Biovolum

e, million um3 / ml

Lake Griffin 

Figure 3. Two key taxa of cyanobacteria, Cylindrospermopsis and Oscillatoria (solid 

line) played an important role in the overall phytoplankton biomass (triangle)(million 

μm3

 / ml) in the Lake Griffin (Phlips, Cichra and Frost 2002). 

32
Summer 94

Summer 95

Summer 96

Summer 97

Summer 98

Summer 99

30,000

Cyanobacteria

Abundance, Cells / ml

20,000

10,000

Cylindrospermopsis sp.

10,000 Anabaena spp.

6,000

2,000

Figure 4. The temporal distribution of two potentially toxic forms of cyanobacteria in 

the St. Johns River (cells / ml) from 1994 through 1999 (Cichra and Phlips 2002). 

33
Figure 5. Phytoplankton biomass (million μm3

 / ml) in four distinct regions of Florida 

Bay. The dominant cyanobacteria, Synechococcus cf. elongatus, is indicated in black 

(Phlips et al.1999). 

34
0

2

4

6

8

10

12

Sep9

7

Oct-9

7

No

v-9

7

Dec-9

7

Jan-9

8

Fe

b-9

8

Mar-9

8

Apr-9

8

M

ay-98

Jun9

8

Jul-98

A

ug-98

Sep9

8

Oct-9

8

No

v-9

8

Dec-9

8

Jan-9

9

Fe

b-9

9

Mar-9

9

Apr-9

9

M

ay-99

Jun9

9

Jul-99

A

ug-99

millio

n μ

m3/ml

Flag

Cyano

Diatom

Crypto

Dino

Euglena

Chloro

Indian River Lagoon

Banana River Region

Figure 6. Phytoplankton biomass (million μm3

 / ml) in the Indian River Lagoon. 

Cyanobacteria (black) was dominated by Synechococcus sp. (Badylak and Phlips 2002). 

35
< 10000

0.5 million

12 million

Suwannee River Estuary

Cyanobacteria

Biovolume, μm3 / ml 

 

Figure 7. Picoplanktonic cyanobacteria biovolume (μm3 / ml) distribution in the 

Suwannee River estuary during peak biomass observed during the summer of 2000. 

Darker shading indicates increased biomass (Bledsoe and Phlips 2002). 

36
CDC—A Brief Introduction 

Lorraine C. Backer, PhD, MPH 

National Center for Environmental Health 

Centers for Disease Control and Prevention 

1600 Clifton Road N.E. 

MS E-23 

Atlanta, GA 30333 

Phone: 404-498-1342 

Fax: 404-498-1355 

What is the Centers for Disease Control and Prevention (CDC)? 

CDC’s mission is to promote health and quality of life, to protect health and safety, 

provide credible information to enhance health decisions, and promote health through 

strong partnerships. CDC is the national focus for developing and applying disease 

prevention and control strategies, environmental health, and health promotion and 

education activities. CDC’s goal is to improve the health of the people of the United 

States; however, CDC does not make regulations, recommend legislation, or impose 

programs on our state partners. 

CDC is an agency within the U.S. Department of Health and Human Services andcompris 

12 offices and centers, including the National Center for Environmental Health (NCEH) 

(see Figure 1). The mission of NCEH is to provide national leadership in preventing and 

controlling disease and death resulting from the interactions between people and their

environment. The NCEH mission is implemented by working with state and local health 

agencies to identify, investigate, and prevent environmentally induced illnesses in people. 

With the exception of the National Institute for Occupational Safety and Health 

(NIOSH), CDC has a presence in a state or local health agency only at the specific 

request and consent of the agency. 

CDC funding sources include congressional budget funds and other programs targeted to 

address a specific public health issue, such as the presence of Pfiesteria piscicida in 

eastern U.S. estuaries. CDC passes much of the funding it receives directly to states in 

the form of grants, cooperative agreements, and other assistance to health agencies. 

CDC and Harmful Algal Blooms 

CDC has been directly involved in HABs research since the summer of 1997, when the 

discovery of Pfiesteria piscicida in the tributaries of the Chesapeake Bay created 

concerns about human exposure to the organism. CDC participated in the public health 

response to complaints of human illness associated with exposure to waters containing 

the organism by sending investigators to assist the state of Maryland in conducting their 

investigation. CDC held a number of workshops and program meetings to encourage 

federal and state health agencies to collaboratively develop a plan to assess the public 

health impact of environmental exposure to this organism. With the states, CDC defined 

a number of public health research needs: 1) Investigate Pfiesteria piscicida, including 

37
the ecology and behavior of the organism, 2) Characterize the toxins elaborated by P. 

piscicida and other estuarine dinoflagellates, 3) Characterize the routes of human 

exposure, such as dermal contact or inhalation of aerosolized toxins, and 4) Conduct 

clinical and epidemiologic studies to determine the human health effects from exposure 

to the organism, similar organisms, and any toxins they produce. 

CDC received direct congressional funding to support a number of harmful algal bloom

(HAB) research activities, including cooperative agreements with six states (Delaware, 

Florida, North Carolina, Maryland, South Carolina, and Virginia) to assess the public 

health impact associated with the presence of Pfiesteria piscicida in estuarine waters used 

for recreational activities and commercial fishing. The states developed programs to: 1) 

Conduct epidemiologic studies, 2) Create public education materials, and 3) Develop 

biological markers of exposure to P. piscicida toxins and their biological effects. 

Detailed descriptions of CDC and state health agency activities associated with P. 

piscicida can be found in the Environmental Health Perspectives Supplement (2001) 

comprising papers presented at the CDC conference (Pfiesteria: From Biology to Public 

Health, Stone Mountain, Georgia, October 18-20, 2000). 

CDC has conducted annual site visits with each of the states involved in the cooperative 

agreements. These site visits have provided opportunities to expand the research initially 

focused on a single organism to the more general issue of the impact of HABs on public 

health. For example, the cooperative agreements have supported a number of additional 

activities, including the investigation of exposure to aerosolized brevetoxins during red 

tide events, a study of the efficacy of home water filters to remove cyanobacterial toxins 

from water, this workshop, and the human health impact of exposure to waste products 

from confined animal feeding operations (CAFOs). 

Future Challenges for CDC 

CDC has defined a number of future challenges in public health. They are: 1) Improve 

people’s health, 2) Prevent violence and unintentional injury, 3) Meet health and safety 

needs of the workforce, 4) Provide credible health information, 5) Protect individuals 

from emerging diseases, 6) Eliminate racial/ethnic disparities, 7) Foster safe, healthy 

environments, and 10) Work with partners to improve global health. Collaborative efforts 

with public health partners will enable CDC to address these future challenges. 

References

Lorraine C. Backer, Lora E. Fleming, Alan Rowan, Yung-Sung Cheng, Janet Benson, 

Richard H. Pierce,Julia Zaias, Judy Bean, Gregory D. Bossart, David Johnson, 

Raul Quimbo, and Daniel G. Baden. Recreational Exposure to Aerosolized 

Brevetoxins During Florida Red Tide Events. Harmful Algae, 2, 2003:19-28 

Pfiesteria: From Biology to Public Health. Environmental Health Perspectives, 109 

(Suppl 5), 2001. 808 pp.

38
Office of the Director

CDC Washington

Office

Office of Program Planning and

Evaluation

Office of

Communication

Office of

Program Support

Office of Women’s

Health

Office of Health

and

Safety

Office of Equal

Employment

Opportunity

National Vaccine

Program Office

Public Health

Practice Program 

Office

International

Health Program

Office

Epidemiology

Program Office

National

Immunization

Program

National Center for Chronic

Disease

Prevention and Health

Promotion

National Center

for

Environmental

Health

National Center

for

Health

Statistics

National Center

for

Infectious

Diseases

National Center

for

Injury

Prevention and

Control

National Center

for

HIV, STD, and

TB Prevention

National Institute

for

Occupational

Safety and Health 

Department of partment of Health and Human Services

Public Health Serv th Service 

Centers for Disease Control and Prevention (CDC)

National Center

on

Birth Defects and

Developmental

Disabilities

Figure 1. Organization chart for Centers for Disease Control and Prevention 

39
Australia’s Cyanobacteria Experience 

Ian Falconer, D.Sc.

The most recent research into toxic cyanobacteria in Australia has had three main 

emphases. These are the ecology of cyanobacteria and its implications for management 

of water bodies; the toxicity and mechanism of action of cylindrospermopsin; and the 

bioaccumulation of toxins by plants and animals used for human consumption. 

Blooms of toxic cyanobacteria in Australia are largely seasonal in occurrence. Some

water storages have successions of blooms of different species, related to water 

temperature and residence time of water in lakes or weir pools. Often these are of toxic 

species, and hence a hazard to domestic animals or human consumers. 

The species Anabaena circinalis is common in lakes, reservoirs and rivers in Australia 

and is toxic as a result of synthesizing a series of saxitoxin derivatives. These are stable 

to boiling and are not removed by conventional chlorination, flocculation, or rapid sand 

filtration water treatment. They can be removed by activated carbon and other more 

sophisticated water treatments. 

The organism blooms most successfully in temperature-stratified rivers or lakes. Under 

these conditions anoxia at the sediment surface releases phosphate, which is the limiting 

nutrient for this nitrogen-fixing species. The implications for management to minimize 

cyanobacterial blooms of this species include flow control in rivers, setting water 

discharge rates to assist mixing, and varying discharge heights (Webster et al., 2000). 

Other ecological research has explored the toxic Cylindrospermopsis raciborskii that

commonly occurs in the tropical lakes and rivers of Northern Australia. Monitoring 47 

storage reservoirs and weir pools showed C. raciborskii in 70%, with highest bloom

density in late summer/autumn. In 14 reservoirs for drinking water storage, the average 

cylindrospermopsin concentration was 3.4 μg/L. Toxin concentrations of 1.0 μg/L were 

reached at a cell concentration of 20,000 cells/ml, which was taken as the health trigger 

for monitoring drinking water for toxicity. High C. raciborskii concentrations were 

associated with long water residence time, high pH, high temperature, high incident 

radiation and a thermally stratified water column (McGregor and Fabbro, 2000). 

Recent studies of cylindrospermopsin have investigated the toxin distribution in mice, 

and the pathway of excretion. Most appears in the urine, with some in the feces. The 

liver and kidney concentrate the toxin, but it occurs widely in the tissues (Norris et al., 

2001). Studies of possible carcinogenicity demonstrated 10% of cylindrospermopsindosed mice developed tumors over 210 days whereas no controls did so (Falconer and 

Humpage, 2001). Parallel studies using a cultured human white blood cell line 

demonstrated that micronucleus formation increased in the presence of 

cylindrospermopsin, indicating chromosome breakage and loss of whole chromosomes 

(Humpage et al., 2000a). A sub chronic oral toxicity trial with cylindrospermopsin has 

just been completed (Humpage and Falconer, 2003). 

40
The potential of microcystin, also an important toxic cyanobacterial contaminant of 

drinking water, as a tumor promoter in the lower gut was demonstrated by an increase in 

pre-neoplastic colon crypts in mice when microcystin was supplied in drinking water 

(Humpage et al., 2000b). 

As a result of major water blooms of Nodularia in a fish and shellfish harvesting area, 

analyses were done on tissues from commercial species. Sufficient toxin was found in 

tissues for shellfish and crustacean harvesting to be banned, and use of finfish restricted 

to 'cleaned' fish only (Van Bounder et al, 2001). 

References 

Falconer, I. R. and Humpage, A. R. (2001) Preliminary evidence for In-Vivo tumor 

initiation by oral administration of extracts of the Blue-Green Alga Cylindrospermopsis 

raciborskii containing the toxin cylindrospermopsin. Environmental Toxicology 16, 192-

195. 

Humpage, A. R., Fenech, M., Thomas, P. and Falconer, I. R. (2000a) Micronucleus 

induction and chromosome loss in WIL2-NS cells exposed to the cyanobacterial toxin, 

cylindrospermopsin. Mutation Research 472, 155-161. 

Humpage, A. R., Hardy, S. J., Moore, E. J., Froscio, S. M. and Falconer, I. R. (2000b) 

Microcystins (cyanobacterial toxins) in drinking water enhance the growth of aberrant 

crypt foci in the mouse colon. Journal of Toxicology and Environmental Health, Part A 

61, 155-165.

Humpage, A.R. and Falconer, I.R. (2003) Oral toxicity of the cyanobacterial toxin 

cylindrospermopsin in male Swiss albino mice: Determination of No Observed Adverse 

Effect Level for deriving a Drinking Water Guideline Value. Environmental Toxicology

18, 94-103. 

McGregor, G. B. and Fabbro, L. D. (2000) Dominance of Cylindrospermopsis raciborskii 

(Nostocales, Cyanoprokaryota) in Queensland tropical and subtropical reservoirs: 

Implications for monitoring and management. Lakes and Reservoirs: Research and 

Management 5, 195-205. 

Norris, R. G. L., Seawright, A. A., Shaw, G. R., Smith, M. J., Chriswell, R. K. and 

Moore, M. R. (2001) Distribution of 14C cylindrospermopsin in vivo in the mouse. 

Environmental Toxicology 16, 498. 

Van Buynder, P. G., Oughtred, T., Kirby, B., Phillips, S., Eaglesham, G., Thomas, K. and 

Burch, M. (2001) Nodularin uptake by seafood during a cyanobacterial bloom.

Environmental Toxicology 16, 468-471. 

41
Webster, I. T., Sherman, B. S., Bormans, M. and Jones, G. (2000) Management strategies 

for cyanobacterial blooms in an impounded lowland river. Regulated Rivers: Research 

and Management 16, 513-525. 

42
CYANOBACTERIAL TOXINS: THE DEVELOPMENT AND EVALUATION OF 

METHODS TO DETERMINE MICROCYSTIN LEVELS IN CANADIAN 

WATER SUPPLIES 

MICHELE GIDDINGS, HEALTH CANADA 

 TIM MACAULAY, SASKATCHEWAN HEALTH 

ABDEL-ILAH SADIKI, HEALTH CANADA 

JOANNE SKETCHELL, SASK WATER 

INTRODUCTION 

In Canada, the provision of safe drinking water demands the cooperation of all 

governments, particularly at the federal and provincial/territorial levels. Since the late 

1960s, these governments have worked together to develop guidelines to maintain or 

improve the quality of drinking water across the country. Federal-provincial 

collaboration in this area ensures citizens have access to the highest quality water 

possible. 

The Federal-Provincial-Territorial Committee on Drinking Water (formerly 

Subcommittee) is made up of representatives from Health Canada's Water Quality and 

Health Bureau, Environment Canada, and provincial and territorial government 

departments responsible for water quality. The group meets twice annually and via 

conference calls at other times to discuss issues related to drinking water quality, 

including: 

* new and on-going research related to the microbiological quality of water,

* new and on-going research related to risks from exposure to particular chemical 

contaminants which may be present in Canadian drinking water supplies, 

* the development of new, and revision of current, guidelines for contaminants 

found in Canadian drinking water supplies, and 

* the publication of educational tools dealing with specific topics for the public, 

health practitioners, and drinking water authorities. 

One of the substances currently under the Committee's evaluation is Microcystin-LR, a 

potent toxin that affects the liver (hepatotoxin). This hepatotoxin is naturally produced 

by many species of blue-green algae (cyanobacteria), which grow in shallow, warm, 

slow-moving or still bodies of water common throughout Canada. Many rural farm-type 

water supplies used for domestic purposes and for livestock watering are subject to 

repeated blue-green algal blooms, particularly during the hot summer months. While 

most species of blue-green algae are capable of producing toxins, not all blue-green algal 

blooms do. When present, the concentration of toxins varies dramatically within the 

body of water and over time. Microcystins are extremely stable and will persist for long 

periods once they are released into a water supply. 

43
This presentation focuses on the development of a Canadian drinking water guideline for 

Microcystin-LR. In order to develop this guideline, federal and provincial governments 

have worked together to conduct surveys to assess risk and to improve available detection 

and testing methods. In particular, an analytical method was developed and a prototype 

field test kit created. The applicability of the analytical method and field test kit for 

routine monitoring will be discussed. The success and implementation of these two 

methods will provide a more accurate and cost-effective approach to the management of 

risk associated with blue-green algal toxins to humans and livestock. 

GUIDELINE DEVELOPMENT 

History 

The first drinking water standards in Canada were developed in 1923. These standards 

dealt with the bacteriological quality of drinking water on ships in the Great Lakes and 

Inland Waters. In 1930 and 1937, they were extended to cover all common carriers and 

coastal shipping, and were adopted in 1954 as regulations under the National Health and 

Welfare Act. Until 1968, federal and provincial drinking water authorities generally used 

the United States Public Health Service Standards as the basis for water quality 

objectives in Canada. In 1968, the first comprehensive Canadian drinking water quality 

guidelines were published. These guidelines, referred to as the Canadian Drinking Water 

Standards and Objectives (Health and Welfare Canada, 1969), were developed by a joint 

committee made up of the Canadian Public Health Association Drinking Water Standards 

Committee and an Advisory Committee convened by the Department of National Health 

and Welfare (now Health Canada). Although the development of the 1968 drinking 

water standards was conceived as a federal initiative, it involved the active participation 

of representatives from provincial agencies. 

Ten years later, the standards were updated, and the 1978 Guidelines for Canadian 

Drinking Water Quality (Health and Welfare Canada, 1979) were published. In addition 

to including more pesticides and organic chemicals, the 1978 Guidelines updated the 

earlier recommendations for radioactive substances. With the exception of pesticides and 

phenols, the presence of organic chemicals in drinking water had largely been ignored 

before the 1970s. Then, in 1974, scientists discovered that trihalomethanes (THMs), a 

group of chlorinated disinfection by-products (CDBPs), could be formed during the 

drinking water treatment process. This discovery awakened interest in the presence of 

organic chemicals in drinking water. Interest focused first on the health significance of 

the THMs themselves, and then on the presence and possible health significance of other 

organic chemicals in drinking water. 

As with earlier efforts, a working group developed the 1978 Guidelines as a joint federalprovincial project with members drawn from each province and territory, as well as from

the federal government. Health Canada provided the technical secretariat to the working 

group, which then reported through the Federal-Provincial Advisory Committee on 

Environmental and Occupational Health, now called the Committee on Environmental 

44
and Occupational Health (CEOH), to the Conference of Deputy Ministers of Health. 

Once its task was completed in 1978, this working group was disbanded. 

However, interest in drinking water quality remained, and in 1983 another working group 

under the same Federal-Provincial Committee began updating the 1978 edition of the 

guidelines. In 1986, this working group was changed to a standing subcommittee, and in 

2002 it was changed to the Federal-Provincial-Territorial Committee on Drinking Water 

(Committee), which exists to this day. 

Since the publication of the 1978 guidelines, further advances in analytical methods, 

particularly in the field of gas chromatography/mass spectrometry, have resulted in the 

detection of a large number of organic chemicals found in drinking water supplies that 

had previously gone unnoticed. Several hundred such chemicals have now been reported 

in Canadian drinking water supplies, and many hundreds more have been found in other 

parts of the world. The concentrations of most of these chemicals are very low, and little 

or no data exists to assess their toxicity. Government and international agencies have 

responded by assessing the need for standards or guidelines for a wide variety of 

substances. 

The sixth, and most recent, edition of the Guidelines for Canadian Drinking Water 

Quality (Health Canada, 1996), published in September 1996, lists guidelines for more

than 80 physical and chemical parameters and for 78 natural or artificial radionuclides. 

As in the 1978 edition, explanatory paragraphs concerning the guideline derivation 

process are an integral part of the booklet. The documents used to support the adoption 

of a particular guideline value are also made available on request, and can be found on 

Health Canada's water quality website (http://www.hc-sc.gc.ca/waterquality or

http://www.hc-sc.gc.ca/eauqualite). In order to keep stakeholders apprised of new or 

revised guidelines between publications of the Guidelines booklet, a Summary Table is 

prepared and posted to the website once each year. 

It should be emphasized that the guidelines are not enforceable standards unless they are 

embodied in provincial or territorial legislation. All provinces and territories use the 

guidelines as the basis for assessing the quality of their drinking water supplies. Most 

provinces have control over the operation of treatment facilities, including the issuance of

operating permits. 

The Committee continues to be made up of representatives from all of the provinces and 

territories, as well as from Health Canada and Environment Canada. Health Canada's

Water Quality and Health Bureau also continues to provide the scientific expertise to the 

Committee, as its technical secretariat. The Committee meets biannually, alternating 

between Ottawa and a city in one of the provinces or territories; the latest meeting was 

held in Winnipeg, Manitoba in April, 2003. At each meeting, members review and revise 

the priority list of substances scheduled for assessment. In recent years, the Committee 

has worked to define the specific roles each level of government plays in the guideline 

development process, and to work together to identify national priorities which take into 

45
account the needs of each jurisdiction. A detailed summary of the Committee's activities 

can be found on the water quality website. 

Current Practices 

Because provincial and territorial governments are responsible for implementing the 

drinking water guidelines and for providing safe drinking water to Canadians, members 

of the Committee are accountable for the evaluation and approval steps of the drinking 

water guidelines development process. Each recommended guideline value, and it’s 

accompanying health risk assessment, is evaluated for its practicality and impact. 

Consultations carried out by the secretariat include posting documents for public 

comment on the water quality website. Regional consultations may be carried out by the 

provinces and territories. Through this consensus-based development process, a 

guideline is established, and the associated health risk assessment is modified to create a 

criteria summary that reflects the risk management decisions involved in the guideline’s 

development. 

The process of developing drinking water guidelines for microbiological, chemical/ 

physical and radiological substances is based on risk management concepts and involves 

several steps: identification, assessment, evaluation, approval, announcement and 

publication (Federal-Provincial Subcommittee on Drinking Water, 1998; Health Canada, 

1995). This process is flexible by nature, in that it must accommodate the diverse needs 

of various jurisdictions (i.e., provincial, territorial and federal) in order to be deemed 

successful. Certain steps within the development process may be modified in order to 

satisfy the needs of the jurisdictions involved. The process used in developing a 

guideline, from the selection of the parameters to be evaluated, through to approval and 

publication, takes several years to complete. 

The guideline development process is broken down into a number of specific actions, 

completed by the various members of the Committee. In general terms, the secretariat 

(the Water Quality and Heath Bureau, Safe Environments Programme, Healthy 

Environments and Consumer Safety Branch), representing the federal government, is 

responsible for providing scientific expertise and advice to the provinces and territories; 

compiling national data on substances under review; assessing health risks; and writing, 

revising and publishing the criteria summary documents and the guidelines booklet as 

needed. The secretariat also maintains the water quality website, which houses many of 

the documents related to the guideline development process. 

The provincial and territorial representatives, on the other hand, are responsible for the 

information for and about their own specific jurisdictions. This includes regulating 

drinking water quality through the adoption of enforceable regulations, guidelines and 

objectives; conducting monitoring programs, and setting-up and maintaining distribution 

systems and treatment plants for drinking water. The Drinking Water Committee, as a 

group, evaluates all available scientific and economic data to establish or revise drinking 

water guidelines through a risk management process. In this way, the work conducted by 

46
the various levels of government complement each other and duplication is kept to a 

minimum.

Drinking water guidelines are developed for substances that appear on the Committee's 

"drinking water substances priority list." In order to be placed on this list, and therefore 

qualify for evaluation, a substance must meet at least one of the following criteria: it must 

be frequently detected in many Canadian drinking water supplies, detected in frequently 

elevated concentrations, or there must be evidence (pre-assessment review) that the 

substance may cause adverse health effects. If the substance meets the criteria, the 

Committee and CEOH place it on a list, which is then approved. This final substance 

priority list can be found on Health Canada's water quality website. The evaluation of the 

substance begins once an evaluator becomes available. Due to limited resources and data 

gaps, many of the substances currently on the priority list are awaiting evaluation. Work 

is also coordinated with other standards-setting organizations, such as the U.S. 

Environmental Protection Agency and the World Health Organization, to minimize 

duplication of research or assessment. 

The evaluator begins the risk assessment by researching the substance through an 

extensive literature and data search, including gathering information from other 

jurisdictions and partners. The provinces and territories become involved at this point by 

identifying whether exposure (monitoring) data on this particular substance is available 

from their own jurisdictions, whether from existing, current or future sampling programs. 

They also indicate when a summary of their monitoring data will be available. The 

results of both these searches are then used to determine whether a need really exists for a 

guideline on this particular substance. 

If a need does exist, jurisdictions concerned about the substance initiate monitoring 

programs to satisfy their own informational needs (e.g., exposure estimates). They 

collect and summarize their monitoring data for the substance and submit their 

summaries to the secretariat for consideration in assessing national exposure to the 

contaminant. This step ensures the process is consistent with the population health 

directions and priorities of provincial, territorial and federal governments. 

The evaluator obtains data on the effects of exposure to chemical agents from

toxicological studies of animal species and in epidemiological studies of human 

populations, where such studies exist. Effects vary, depending upon the dosage, route of 

exposure (e.g., ingestion, inhalation or dermal), frequency or duration of exposure and 

the species, and the sex and age of the exposed population. The effects of exposure to 

chemicals are generally classified in the following broad categories: organ-specific, 

neurological/behavioral, reproductive, teratological and oncogenic/carcinogenic/ 

mutagenic. Effects may be brief or prolonged, reversible or irreversible, immediate or 

delayed, single or multiple. In general, the nature, number, severity, incidence and/or 

prevalence of specific effects in a population generally increase with increasing dose; this 

is commonly referred to as the dose-response relationship. 

47
For some types of toxic effects resulting from exposure to chemicals, it is believed that a 

dose (threshold) exists below which adverse effects will not occur. For other types of 

toxic effects, it is assumed, but not proven, that some probability of harm exists at any

level of exposure (i.e., no threshold). At present, the latter assumption is generally 

considered to be appropriate only for carcinogenesis. For some types of carcinogens, 

specifically those that induce tumors by particular mechanisms, such as promotion, it is 

believed that a threshold dose may exist below which tumors will not occur. 

Different approaches are adopted for the derivation of guidelines for compounds 

considered to be carcinogenic and probably carcinogenic, compounds considered to be 

possibly carcinogenic and those considered being probably not carcinogenic or for which 

data are inadequate for evaluation. Chemicals are therefore classified with respect to 

their potential carcinogenicity into various groups on the basis of rigorous examination of 

the quantity, quality and nature of the results of available toxicological and 

epidemiological studies. Chemicals classified as carcinogenic often also induce toxic 

effects other than malignant tumors; for these substances, the guideline is derived on the 

basis of the approach that leads to the most stringent value. 

If the substance undergoing evaluation is found to be not carcinogenic to humans, its 

recommended drinking water guideline value is derived based on the application of an 

uncertainty factor to account for inter- and intraspecies variation to a no-observedadverse-effect level observed in toxicological studies in which rats ingest the substance in 

drinking water daily for periods ranging from 90 days to two years. 

Once the evaluator has compiled the above data, he or she drafts a criteria summary on 

the substance, incorporating the health risk assessment information, the overall 

environmental exposure to the substance, the fraction of its exposure attributed to 

drinking water, existing analytical/treatment techniques and capabilities, as well as a 

recommended guideline value. 

The first review of the draft criteria summary is completed within the Water Quality and 

Health Bureau; the evaluator defends the classification of the substance and its proposed 

guideline value to a senior evaluator. The criteria summary is then revised to reflect the 

experience of the senior evaluator, who must be completely satisfied with the criteria 

summary before it is forwarded for an external review. 

The evaluator then sends the draft criteria summary to three external or third party 

reviewers who have expert knowledge of the substance. These third-party reviewers are 

from Canadian or American universities, the U.S. Environmental Protection Agency 

Drinking Water Program or a Member State of the World Health Organization. Also 

included among the reviewers is a drinking water treatment specialist, often 

recommended by the Canadian Water and Wastewater Association. These experts 

critically review the criteria summary in accordance with the Canadian published 

approach policy and respond to questions set out in a guide for peer reviewers. Their 

review focuses on the scientific component of the summary. 

48
Once the third-party reviewers written comments are received, the evaluator assesses the 

comments and considers any additional information identified by the reviewers. The 

evaluator then revises the criteria summary and submits it for a final internal review.

The criteria summary is then distributed to the Committee members for their review of 

the substance's health risk assessment and the proposed guideline value. 

Provincial/territorial review and assessment of the criteria summary varies from a brief 

departmental (internal) review to detailed evaluations by an external agency or nongovernmental organization. Written comments from all Committee members are 

forwarded to the secretariat for consideration by the evaluator. 

Once the risk assessment phase winds down, the process of risk management becomes 

more prominent. Each jurisdiction evaluates the feasibility of implementing the 

recommended guideline for the substance in drinking water by taking treatment costs and 

socio-economic factors into consideration. A revised criteria summary is then redrafted 

for public comment. This document contains as much provincial exposure and economic 

information as is available at the time of printing. It is then made available to the public 

for comment through the provincial representatives and the secretariat. The documents 

are also available through the water quality website for public comment during a 

specified period (usually 4 months). 

Following the public review, all comments are again reviewed and summarized by the 

evaluator and presented to the Committee. Jurisdictions concerned that people living in 

their area may be exposed to drinking water containing the substance at concentrations 

that exceed the recommended guideline value will estimate the costs for treating drinking 

water to reduce the concentration of the substance. The costs of controlling exposure to 

the substance from sources other than drinking water may also be estimated in order to 

confirm that modifying water treatment is in fact the most cost-effective way of reducing 

intake of the substance. Control of other routes of exposure may be identified as a more 

effective means for reducing the particular health risk. The development of these cost 

estimates is the responsibility of Committee members; the level of detail of the cost 

estimates is left to their discretion. 

Weighed against these costs are the benefits of reducing exposure to the substance via 

drinking water if such data are available. For example, there may be direct savings in 

health care costs that would otherwise be incurred from a specific health problem

associated with the substance, or indirect savings in the form of socio-economic benefits 

such as savings in sick leave and subsequent increases in production. Any side benefits 

that are an outcome of improved drinking water treatment to control the substance (e.g., 

the removal of other contaminants or the extension of the life of the water distribution 

system) may be considered in a cost-benefit analysis. 

When the new or revised guideline for a particular substance has been approved by the 

Committee and then CEOH, the secretariat evaluator makes all the required revisions to 

the criteria summary in preparation for its publication in the Guidelines for Canadian 

49
Drinking Water Quality Supporting Documentation. The final criteria summary is 

published in both official languages, and is made available on the water quality website. 

The guideline value for the substance is included in the summary table of drinking water 

guidelines found in the “Guidelines for Canadian Drinking Water Quality” supporting 

documentation and is posted on the website. This table is updated annually, following 

each spring meeting of the Committee. Notice is also sent out to subscribers to the Water 

Quality and Health Bureau’s List serve/mailing list. The guideline is also included in the 

“Guidelines for Canadian Drinking Water Quality” booklet when updated. 

Re-evaluation of existing guidelines is a continuous process. Although the secretariat is 

charged with the responsibility of identifying outdated guidelines each year when the

Committee list of substances is established, any Committee member or interested party 

can identify an outdated guideline. The availability of new research, monitoring data, 

analytical methodology or treatment process may prompt a re-evaluation of an existing 

guideline. 

Although its primary task was initially to develop drinking water guidelines, the role of 

the Committee has evolved to deal with a variety of issues concerning treatment 

technologies and the quality of drinking water. A partial list of the Committee's current 

priorities in the area of risk management and guideline development focuses both on the 

microbiological quality of drinking water and on chemical substances or groups of 

substances from the drinking water disinfection process: protozoa, chlorinated 

disinfection by-products (CDBPs), uranium, and cyanobacterial toxins (Microcystin-LR). 

Furthermore, Health Canada provides timely advice to other government agencies and 

departments, the provinces, the territories, and the public in response to emergency 

situations, such as spills. 

CYANOBACTERIAL BLOOMS AND MICROCYSTIN-LR 

Cyanobacteria, uni- or multi-cellular prokaryotes that contain chlorophyll, form in 

shallow, warm, slow moving or still water. A mass of cyanobacteria in a body of water 

(commonly referred to as pond scum) is called a bloom. Far from being a new 

phenomenon, cyanobacterial blooms have been around for centuries. Cyanobacteria 

sometimes produce toxins that either affect the nervous system (neurotoxins) or the liver 

(hepatotoxins). Cyanobacterial neurotoxins are extremely unstable, which makes them

difficult to isolate and study; cyanobacterial hepatotoxins, on the other hand, are 

extremely stable. 

Most hepatotoxins produced and released by cyanobacteria are called microcystins 

because they were first isolated from a cyanobacterium called Microcystis aeruginosa. 

Microcystins are the most common of the cyanobacterial toxins found in water, and 

probably the ones most often responsible for poisoning animals and humans who come 

into contact with toxic blooms. Microcystins are extremely stable in water because of 

their chemical structure, which means they can survive in both warm and cold water and 

50
can tolerate radical changes in water chemistry, including pH. So far, more than 50 

different kinds of microcystins have been isolated and identified. 

Regardless of the type of toxin, determining which cyanobacterial blooms are toxic and 

which are harmless is a complicated task. Researchers generally agree that 30 to 50 per 

cent of cyanobacterial blooms are harmless because they contain only non-toxic species 

of freshwater cyanobacteria. Currently, toxicity can only be determined through 

laboratory testing. However, because cyanobacterial blooms are becoming more and 

more common in surface waters across Canada, Health Canada and Committee members 

from affected jurisdictions have initiated a project that will help ascertain the toxicity of

blooms in a simple, accurate, and efficient manner. One of the project's outcomes is a 

simple field test and analytical method that will allow regular and more cost-effective 

monitoring of this substance. 

Canadian Drinking Water Guideline for Microcystin-LR 

Health Canada, as the technical secretariat to the Committee, has adopted a guideline 

value of 1.5 μg/L for Microcystin-LR. It is expected that this value will be protective of 

effects from other microcystins since M-LR is the most common of the toxins found in 

Canadian drinking water sources. The final criteria summary document for MicrocystinLR is posted on the water quality website. The value is believed to be conservative as it 

is based on lifetime oral exposure. For climatic reasons, toxins are probably not present 

in Canadian water supplies more than four or five months per year. 

Some municipal treatment plants are now required to monitor for the presence of 

Microcystin-LR in their water supplies, especially if the source is prone to cyanobacterial 

blooms. Because maintaining drinking water quality in Canada is a provincial 

responsibility, monitoring and treatment strategies will vary between provinces. To help 

provincial authorities in dealing with elevated levels of toxins found in a given water 

supply, the Committee has also developed a risk management strategy (flow chart) as part 

of the guideline document. 

Cyanobacterial Blooms and Toxins in Canada

While cyanobacterial blooms occur in all provinces, they are most commonly found in 

the small, shallow, slow-moving bodies of water common to the prairies (Alberta, 

Saskatchewan, and Manitoba). Rural prairie towns are the most affected as they 

generally rely on surface water from shallow, nutrient-rich lakes for drinking water, and 

dugouts for domestic purposes and for watering livestock. Cyanobacterial blooms and 

their toxins do not appear in groundwater supplies. 

In the summer of 1990, microcystin-LR was detected in cyanobacterial blooms on three 

shallow Alberta lakes used as sources for municipal drinking water (Kenefick et al., 

1992). Microcystin-LR was present in concentrations up to 500 μg/g of algal biomass. 

More than 70% of more than 380 bloom biomass samples taken from 19 lakes in Alberta 

between 1990 and 1992 showed detectable levels of the toxin (>1 μg microcystin-LR/g of 

51
dry biomass). Levels of microcystin-LR in Alberta lakes and dugout ponds, measured 

using high-performance liquid chromatography with ultraviolet detection, ranged from 4 

to 605 μg/g dry weight of biomass or up to 1500 μg/g. 

In late August 1993, a large algal bloom developed in Deacon Reservoir, Winnipeg's 

main storage facility for water from Shoal Lake. The water from this lake is generally 

considered to be of high quality and requires only disinfection with chlorine prior to 

distribution and consumption. In an attempt to control algal density and taste and odor 

problems, municipal officials isolated the reservoir and treated it with copper sulphate. 

However, this action raised the concern that if the algal bloom contained toxin-producing 

algae, significant quantities of the toxins may have been released into the reservoir. 

Sampling determined that toxin-producing blue-green algae were not present in the 

Deacon Reservoir, but they were present in Shoal Lake. Analysis of water samples 

(using the protein phosphatase bioassay) indicated that microcystin-LR was present in 

samples collected from Shoal Lake and from within the distribution system, but was not 

present at detectable levels (>0.05 μg/L) in samples from Deacon Reservoir. Maximum 

microcystin-LR concentrations measured in the raw water of Shoal Lake and in treated 

tap water were approximately 0.45 μg/L and 0.55 μg/L, respectively. Subsequent 

monitoring during the fall period showed a steep decline in concentrations, suggesting 

that higher microcystin-LR levels may have been present earlier in August 1993. 

Because the weather during the summer of 1993 was characterized by below-normal 

temperatures and above-normal precipitation, conditions not usually supportive of algal 

bloom formation, a concern was raised that higher levels of microcystin-LR could 

develop in Shoal Lake during the more usual, relatively hot, dry summers. As a result, 

Manitoba Environment, in cooperation with the City of Winnipeg, continued to monitor 

for microcystin-LR in Winnipeg's water supply. Microcystin-LR was detected at 

concentrations ranging from 0.1 to 0.5 μg/L on six occasions between 1994 and the end 

of 1996. 

Because Shoal Lake, a relatively nutrient-poor water supply, supported a toxic blue-green 

algal bloom, Manitoba Environment became concerned that toxic blooms may also be 

occurring in more nutrient-rich rural surface water supplies throughout southern 

Manitoba. To address these concerns, a comprehensive two-year study (1995 and 1996) 

was conducted on water quality in rural southwestern Manitoba surface water supplies. 

In the first year of the study, microcystin-LR was found to be widely distributed in all 

water supply categories. Rural municipal water supplies had a higher detection 

frequency (93%) than on-farm domestic/livestock dugouts (57%), showing that 

conventional treatment methods may be only partially successful in removing the toxin. 

Mean concentrations ranged from 0.23 μg/L in recreational sites to 0.35 μg/L in dugouts 

used exclusively for livestock. In the second year of the study, seven rural surface water 

supplies were intensively sampled for microcystin-LR. The hepatotoxin was found 

throughout the entire sampling period (June through December 1996), sometimes at 

levels exceeding 0.5 μg/L, the "Emergency Health Advisory Guideline" formulated by 

Health Canada in response to the 1993 incident. 

52
Several incidents of suspected animal poisonings have been associated with toxic algal 

blooms in Manitoba lakes. In June 1995, hepatotoxin poisoning was suspected in the 

deaths of two calves watering directly from Pelican Lake, where a massive bloom was

associated with microcystin-LR concentrations ranging from 0.8 to 1.2 μg/L. In midJune 1996, 16 cattle and a dog died after drinking water from a creek impoundment near 

Balder. Although microcystin-LR concentrations were relatively low (0.4 and 0.23 

μg/L), the neurotoxin-producing blue-green algal genus Anabaena dominated the algal 

composition. In July 1996, three dogs died after drinking water from recreational beaches 

along Dauphin Lake. Again, water samples contained low levels of microcystin-LR (<0.1 

to 0.1 μg/L), but the dominant algal species were neurotoxin-producing Anabaena

species. "Toxic Algae Advisory" signs were posted along Dauphin Lake beaches to warn 

residents about the risks associated with using the lake for drinking water, pet watering, 

or swimming. 

Treatment Technology and Management 

Good control technology must reflect: 

* proper management of the watershed and reservoir to prevent algal growth, 

* an appropriate monitoring program, and 

* correct treatment technology for both the cyanobacteria and their toxins. 

Management options are similar to common techniques used to control algal populations 

in reservoirs, but with a few exceptions. For example, the use of chemicals that would 

lead to the disintegration (lysis) of cyanobacterial cells must be avoided to prevent the 

release of their toxins. In the past, chemical treatment with copper sulphate had been the 

most common technique used to control algal blooms in drinking water reservoirs. 

However, Kenefick et al. (1993) found that algal bloom material from a Canadian prairie 

lake treated with copper sulphate released most of its toxins during the first three days 

following treatment. Their results indicated that a 99% reduction in microcystin levels 

would take approximately three weeks, suggesting that copper sulphate should not be 

used to treat potentially toxic cyanobacterial blooms in waters to be consumed by humans 

within several weeks following treatment. 

An appropriate monitoring program is essential to the overall control of cyanobacteria 

and their toxins. At present, most municipal water treatment plants in Canada do not 

regularly monitor their water supplies for cyanobacterial toxins. However, because 

cyanobacteria have strong smells and tastes and interfere with certain water treatment 

processes, most municipalities with a history of blooms monitor their surface water 

supplies for cyanobacteria. 

Monitoring programs must take spatial and temporal variability in microcystin levels into 

consideration, as there may be large fluctuations in the levels of cyanobacteria and their 

53
toxins resulting from the interplay of a variety of physical, chemical and biological 

factors. Kotak et al. (1995) studied the patterns of occurrence of microcystin-LR 

(measured as μg/g biomass of Microcystis aeruginosa) in three hypereutrophic hard 

water lakes in central Alberta over three seasons. Microcystis aeruginosa was highly 

variable both temporally and spatially, with differences up to three orders of magnitude 

within each lake over one year, between years in an individual lake and between lakes in 

a year. Seasonal changes in microcystin-LR concentration were positively correlated to 

the abundance and biomass of the M. aeruginosa, total and total dissolved phosphorus 

concentration, pH, and chlorophyll. There was a negative correlation between 

microcystin-LR concentration and nitrate concentration and no correlation with water 

temperature. Over a 24-hour period, the concentration of microcystin-LR was six times 

lower at night than during the day. 

The final step in controlling cyanobacteria and their toxins is the drinking water treatment 

process. Although conventional surface water treatment plants using coagulation, 

clarification, and filtration are effective in removing cyanobacterial cells, the Manitoba 

study noted above (Jones, 1996) illustrated that conventional water treatment methods 

may be only partially successful in removing cyanobacterial toxins. This has been 

confirmed by Lambert et al. (1996), who examined the removal of microcystins from

drinking water at two full-scale treatment plants in Alberta that employed coagulationsedimentation, dual-media filtration, and chlorination combined with either granular 

activated carbon or powdered activated carbon filtration. The two processes generally 

removed more than 80% of the microcystin from raw water, particularly when the raw 

water concentrations were high; however, a residual concentration of 0.05-0.2 μg 

microcystin-LR equivalents/L was observed at both treatment facilities. The data thus 

suggests that drinking water consumers could be chronically exposed to low levels of 

microcystin-LR for the duration of cyanobacterial blooms. As previously mentioned, 

Lambert et al. (1996) also found that chlorination was unsuccessful in achieving any 

reduction in microcystins. 

Development of an Analytical Method

In 1997/98, Health Canada was approached by Saskatchewan Health to help develop an 

analytical method to detect and assess the toxicity of cyanobacterial blooms in an 

affordable, efficient, reliable, and routine way. After discussion with the Saskatchewan 

Health Provincial Laboratory staff, it was concluded that the most suitable method would 

use High Performance Liquid Chromatography with UV detection (HPLC-UV). 

Among the several analytical methods using HPLC-UV for microcystin analysis, a 

procedure published by HMSO (London, UK) in 1998 was chosen for modification. This 

method is part of the series Methods for the Examination of Waters and Associated 

Materials, and was developed to detect and quantify dissolved microcystin-LR, 

microcystin-RR, microcystin-YR and nodularin in raw and treated waters (extra-cellular 

toxins). 

54
The procedure consists of multiple steps. First, samples are filtered to remove algal cells. 

The filtrate is then extracted using a preconditioned C18 phase extraction cartridge. The 

cartridge is washed with aqueous methanol before elution with methanolic trifluoroacetic 

acid (0.1%v/v). The acidified methanol is reduced to dryness; the residue is redissolved 

in methanol and again evaporated to dryness. The residue is taken up in 70 percent 

aqueous methanol and centrifuged (if necessary) to remove solid material. A portion of 

the supernatant solution is analyzed by reversed-phase high performance liquid 

chromatography with UV detection at 238 nm, using a photodiode array detector. 

During the initial method evaluation conducted by Health Canada, two major difficulties 

arose. The first problem was the high background and interference peaks in the HPLC 

chromatograms. The second was the obtained detection limit, comparatively higher than 

reported in the published method. 

Multiple attempts were carried out by changing several of the procedure parameters. The 

high background and interference peaks disappeared after the cartridge conditioning 

procedure was modified by passing 5 mL of methanolic trifluoroacetic acid (0.1%v/v) 

through it at the very beginning of the conditioning. The detection limit was slightly 

improved by increasing the cartridge elution volume (4.0 mL instead of 3.0 mL of 

methanolic trifluoroacetic acid (0.1%v/v). During the development of the analytical 

method, duplicate samples were sent to a Health Canada lab in Ottawa in addition to the 

University of Alberta Protein Phosphatase Bioassay Service, the only laboratory in 

Canada that had the capacity to routinely quantify blue-green algae toxins in water. The 

per sample cost for testing via this method is high, therefore making this method 

unsuitable for routine monitoring practices. 

Using the modified analytical method for a 500 mL water sample, microcystin-LR can be 

detected at levels as low as 0.3 μg/L. The minimum quantifiable limit (MQL) is 0.8 

μg/L. The MQL for the three other microcystins (-RR, -LA and -YR) is similar (0.5-0.8 

μg/L). Work is continuing on refining of the method. 

Evaluation and Testing 

During the evaluation and testing phase, sampling was carried out at various sites in 

several provinces in Canada. During 1998, 279 raw water samples were collected from 

different surface water sources (lakes, rivers, dugouts, etc.). These samples were tested 

using the protein phosphatase method; 28 samples tested positive (0.3 μg/L to 14 μg/L). 

Thirty-two duplicate samples (randomly selected from the original 279 samples) were 

sent to the Health Canada lab for testing using the HPLC method. Unfortunately, none of 

these samples tested positive. (Because the samples were selected randomly, there was 

no guarantee of hitting a positive sample). 

During the 1999 surveys, 92 samples were collected and analyzed using the protein 

phosphatase method, and 49 randomly selected duplicate samples were sent to the Health 

Canada lab for testing using the HPLC method. This time, 27 of the original 92 samples 

tested positive (0.3 μg/L to 9.4 μg/L), as did seven of the 49 random samples. 

55
In both surveys, treated water samples were analyzed only if microcystins were detected 

in the raw water supply. The flow charts in Appendix A show the process used during 

the 1999 survey to determine which bodies of raw water to sample, when to test treated 

water, and when to notify the community and potentially switch to an alternative water 

supply or adjust treatment. Appendix A shows the process for water destined for human 

consumption. 

Survey Results

As mentioned above, no microcystins were detected in water samples tested using the 

HPLC method during the 1998 survey. In 1999, Microcystins -LR, -LA and -RR were 

detected in seven raw water samples (mainly recreational sites) at concentrations ranging 

from 0.3 to 3.1 μg/L. One sample contained both Microcystin-LR and -RR. None of the 

four screened microcystins were detected in treated water samples. 

Other unknown compounds that could be part of the microcystin family were detected in 

several samples. Attempts to identify such compounds by liquid chromatography-mass 

spectrometry will be carried out during the summer of 2000. 

Development of a Field Test Kit

As mentioned earlier, the tools available to governments and the public to address 

concerns about the presence of toxins in cyanobacterial blooms are extremely limited. 

The field test kit, based on Dr. Holmes’ protein phosphatase method, is being developed 

to complement the analytical method as a quick, easy to use, readily available tool to 

determine whether cyanobacterial toxins are present in an affected water supply. This 

tool will be useful for: 

* municipal water utilities and agencies responsible for drinking water quality to 

monitor supplies for toxins, 

* agencies responsible for recreational water quality to monitor surface water 

bodies used for recreational contact purposes for toxins, and 

* livestock owners and agricultural agencies in determining the safety of water for 

livestock consumption. 

The prototype field test kit is a non-radioactive assay which exploits the ability of

microcystins to specifically inhibit the type-1 protein phosphatase (PP-1). This 

colorimetric assay is reproducible, fast, and capable of handling a large number of 

samples with little training or equipment. The kit allows untrained individuals to visually 

confirm the presence or absence of toxin in a water sample by comparing the color 

reaction against a control sample. The absence of toxin results in a clear yellow color 

whereas in the presence of the toxin, the solution becomes colorless. This comparison 

will also enable the individual performing the test to get an approximate idea of the 

56
amount of toxin present in the sample (positive control is 1.5 μg/L M-LR). The 

prototype kit was validated during field trials in the summer of 2000. The summer trials 

will allow validation testing of variables such as the effects of turbidity, the stability of

the PP-1, and the shelf life and storage time for the PP-1. 

Test kit results will only be used as an initial indicator of the presence/absence of toxins. 

Final determination of water safety will be based on toxin level results derived from a 

laboratory analytical methodology. Currently, authorities must issue warnings regarding 

the use of water by humans, pets, or livestock where cyanobacterial blooms have 

developed. Where doubt exists about the safety of the water, the public must avoid the 

use of a particular water supply for drinking or recreation. This type of blanket approach 

is unsatisfactory 

Future Applications

In addition to its significance for drinking and recreational water authorities, the 

development of the field test kit is also important to livestock producers throughout the 

country, as the loss of any livestock can have serious financial implications. This tool 

will assist livestock owners to manage their resources by providing them with a rapid 

method to determine the safety of water used for their herds. Early detection of the 

toxins will not only result in decreasing the chances of financial loss due to livestock 

deaths, but will also help eliminate any concerns that may be held by livestock owners 

and buyers that meat from cattle which have consumed water contaminated by blue-green 

algae is tainted. 

CONCLUSION

In conclusion, the quality of drinking water in Canada, indeed the envy of most of the 

world, can be directly linked to a successful system of federal-provincial cooperation in 

assessing and managing health risks associated with its drinking water supplies. Over the 

past twenty years, the federal, provincial and territorial governments have worked 

together to develop and revise guidelines for substances found in Canadian water supplies 

to maintain and improve water quality. This relationship has evolved to include more 

than just guideline development, as can be seen by the current project to develop 

improved tools to monitor the presence of cyanobacterial toxins (microcystin-LR) in 

blue-green algae blooms. The success and implementation of the analytical method and 

the field test kit will provide a more accurate and cost-effective approach to the 

management of risk associated with blue-green algal toxins to humans and livestock. 

References

Health and Welfare Canada (1969). Canadian Drinking Water Standards and Objectives, 

1968. Prepared by the Joint Committee on Drinking Water Standards of the 

Advisory Committee on Public Health Engineering, Department of National 

Health and Welfare and The Canadian Public Health Association. Ottawa. 

57
Health and Welfare Canada (1979), Guidelines for Canadian Drinking Water Quality,

1978. Supply and Services Canada, H48-10-1978. 

Health Canada (1996). Guidelines for Canadian Drinking Water Quality - Sixth 

Edition. Supply and Services Canada, H48-10/1996E. 

Federal-Provincial Subcommittee on Drinking Water (1998). Canadian Drinking Water 

Guidelines. Development Process. July1998 

Health Canada (1995). Guidelines for Canadian Drinking Water Quality. Supporting 

Documentation. Part I. Approach to the Derivation of Drinking Water Guidelines. 

Ottawa. Environmental Health Directorate. 

Health Canada (1993) Guidelines for Canadian Drinking Water Quality. Supporting 

Documentation. Part II. Trihalomethanes. Ottawa. Environmental Health 

Directorate.

Health and Welfare Canada (1978). Guidelines for Canadian Drinking Water Quality. 

Supporting Documentation. Uranium. Ottawa. Environmental Health Directorate. 

Health Canada (1987). Guidelines for Canadian Drinking Water Quality. Supporting 

Documentation. Part II. Uranium. Ottawa. Environmental Health Directorate. 

Health Canada (in press). Uranium in Drinking Water. Document for Public Comment. 

Ottawa. Environmental Health Directorate. 

Health Canada (1998). Guidelines for Canadian Drinking Water Quality. Supporting 

Documentation. Part IIAluminum. Ottawa. Environmental Health Directorate. 

Health Canada (1998). Cyanobacterial Toxins - Microcystins in Drinking Water. 

Document for Public Comment. Ottawa. Environmental Health Directorate. 

HMSO. (1998). The determination of microcystin algal toxins in raw and treated 

waters by high performance liquid chromatography. Methods for the 

Examination of Waters and Associated Materials. London, UK, 1998. 

Hrudey, S.E., Lambert, T.W. and Kenefick, S.L. (1994). Health risk assessment of 

microcystins in drinking water supplies. In: Toxic cyanobacteria a global 

perspective. March 28, 1994, Adelaide, South Australia. Australian Centre for 

Water Quality Research, Salisbury, Australia. pp.12. 

Gurney, S. and Jones, G. (1997) Toxic algae occurrence and distribution in Manitoba 

surface waters. Proceedings of the Rural Water Quality Symposium, March 25-

26, 1997, Winnipeg, Manitoba. 

Jones, G., Gurney, S. and Rocan, D. (1996) Water Quality/Toxic Algae Study Interim 

Report: Summary of the 1995 Field Season Results. Manitoba Environment, 

June 4, 1996. 

58
Jones, G. (1996). Toxic algae study summary. Manitoba Department of Environment, 

February. 

Kenefick, S.L., Hrudey, S.E., Peterson, H.G. and Prepas, E.E. (1993). Toxin release from 

Microcystis aeruginosa after chemical treatment. Water Sci. Technol., 27: 

433-440. 

Kenefick, S.L., Hrudey, S.E., Prepas, E.E., Motkosky, N. and Peterson, H.G. (1992). 

Odorous substances and cyanobacterial toxins in prairie drinking water sources. 

Water Sci. Technol., 25: 147-154. 

Kotak, B.G., Kenefick, S.L., Fritz, D.L., Rousseaux, C.G., Prepas, E.E. and Hrudey, S.E. 

(1993). Occurrence and toxicological evaluation of cyanobacterial toxins in 

Alberta lakes and farm dugouts. Water Res., 27(3): 495-506. 

Kotak, B.G., Lam, A. J-Y., Prepas, E.E., Kenefick, S.L. and Hrudey, S.E. (1995). 

Variability of the hepatotoxin microcysitn-LR in hypereutrophic drinking water 

lakes. J. Phycol., 31: 248-263. 

Lambert, T.W., Holmes, C.F.B. and Hrudey, S.E. (1996). Adsorption of microcystin-LR 

by activated carbon and removal in full-scale water treatment. Water Res., 30 (6): 

1411-1422. 

Annex A: Stepwise Protocol for Microcystin-LR 

in Water Supplies Used for Human Consumption 

Preamble 

Summer conditions can lead to the growth of blue-green algae in bodies of water 

(generally smaller or shallow lakes, reservoirs, sloughs or dugouts) throughout Canada. 

In many cases, blooms tend to recur within the same bodies of water year after year. 

While most species of blue-green algae are capable of producing nerve and liver toxins, 

not all blue-green algal blooms produce toxins, and, when present, the amount of toxins 

varies dramatically within the body of water and over time. Analytical studies over the 

past few years in dugouts and other water supplies in Manitoba, Saskatchewan and the 

Peace River region of Alberta indicate that blue-green algal toxins are much more 

common in rural water supplies than originally thought. Although there are few 

quantitative data available, there are indications that these toxins may also be occurring in 

various water supplies in other provinces (e.g., Ontario, British Columbia, Quebec and 

Prince Edward Island).

The factors inducing the production of toxins by cyanobacteria are not well known. 

Laboratory studies demonstrate that some environmental factors, such as temperature, 

light, nitrogen concentrations, carbon availability (in the form of bicarbonate, carbonate 

59
and carbon dioxide), phosphate concentrations and pH, could be important. As toxin 

production varies greatly among different strains of the same species, genetic differences 

and metabolic processes may also be important in the production of these secondary 

metabolites. Studies have shown that the ability to produce toxins can vary temporally 

and spatially at a particular site. Cyanobacterial toxins tend to be associated with 

cyanobacterial cells and may be membrane bound or occur free within the cells. In 

laboratory studies, most of the toxin release occurs as cells age and die and passively leak 

their cellular contents; some active release of toxins can also occur from young, growing 

cells. Toxin levels do not necessarily coincide with maximum algal biomass; there can

be significant variation in the amount of toxin per unit biomass of cyanobacteria over 

time, which is independent of changes in the blue-green algal population. Concentrations 

of microcystins were higher in blooms taken during the day than at night in one study, for 

example, and no significant difference in toxin concentrations from cyanobacteria 

incubated for 24 hours at different depths in a reservoir was observed in another study. 

Microcystins are relatively persistent in the aquatic environment. Studies in Australia 

have shown that microcystin-LR was present up to 21 days following treatment of a 

Microcystin aeruginosa bloom with an algicide.

Recent studies have led to increasing concern by government agencies and the public 

regarding the safety of water supplies that may be potential sources of these toxins. The 

purpose of this annex and the accompanying flow chart (see next page) is to provide

water purveyors and health and environment authorities with a summary of the important 

factors that should be considered during bloom events and recommendations on actions 

that may be taken to address the issue.

60
Step 1: Visually monitor for bloom formation 

As blooms tend to recur in the same water supplies, water bodies that have historically 

exhibited algal blooms should be visually monitored for bloom formation and hence toxin 

production during the peak season (usually late May to early October). Authorities should 

visually monitor supplies for algal growth and conduct sampling during and after collapse 

of the bloom. As well, bodies of water that, due to variables such as size, water depth and 

nutrient content, may be susceptible to algal blooms should be considered for monitoring 

programs. Toxins may persist following the collapse of blooms, particularly in the late 

summer and early fall, when the onset of colder temperatures and decrease in light 

intensity result in decreased rates of toxin degradation. A visual bloom is identified by 

61
the appearance of “soupy” water. Colours can range from grey or tan to blue-green or 

bright blue or reddish. The appearance of blooms may also be described as fine grass 

clippings or small clumps. 

Step 2: Sample raw1 and treated supplies for toxin (algal identification) 

Samples of raw and treated supplies (if applicable) should be taken at the same time in 

order to save time and money. For laboratory analysis, raw water samples should be 

collected prior to any treatment, including filtration; samples from the raw water tap at 

the treatment plant are acceptable if no pretreatment is applied. Sampling from a reservoir 

should be done as close to the inlet/shore and/or the bloom formation as possible. 

However, when possible, it is suggested that samples from several sites be pooled for the 

determination of toxicity, as cyanobacterial species/cell abundance and biomass vary 

spatially within a water body (e.g., cells may be transported by wind currents). Treated 

samples should be taken at the treated water tap of the treatment plant or within the 

distribution system.

Samples, in amounts required by the analytical laboratory, should be collected in glass 

containers, as studies indicate that the toxin, if present, can be adsorbed to the plastic. 

Agencies may also wish to sample for algal identification. Species identification, 

especially from sites positive for toxin, can provide additional information regarding the 

source, conditions and type of other toxins that might be present. 

1 A field test kit could be used as a screening tool to determine the presence or absence of 

toxin in a water supply. If the presence of toxin is detected in a sample using the field test 

kit, the sampling agency will need to submit a sample to a recognized laboratory for 

confirmatory analytical analysis (see Step 3). 

Step 3: Send both raw and treated samples for microcystin-LR analysis 

Both raw and treated samples should be sent (in coolers) to the laboratory for analysis as 

soon as possible (preferably within 24 hours). Sampling agencies should contact their 

local or regional departments of health or environment for information on laboratories 

capable of conducting toxin analyses. Upon receipt of samples from sampling agencies 

and in order to avoid unnecessary costs, the laboratory should store the treated samples 

until the results of the microcystin-LR analysis of the raw samples are available. A 

microcystin-LR result of >1.0 μg/L in the raw sample will cause further action, as 

outlined in Steps 4–10. 

Step 4: Microcystin-LR >1.0 μg/L (raw) 

Results will be reported to the sampling agency, as per Step 12 (raw). A result of >1.0 

μg/L should cause further action, as outlined in Steps 5–10. 

Step 5: Perform toxin analysis of treated water samples 

Testing will be performed on treated samples when a level of >1.0 μg microcystin-LR/L 

is found in a raw sample from the same site. 

Step 6: Microcystin-LR >1.5 μg/L (treated) 

62
A result of >1.5 μg microcystin-LR/L for the treated sample will cause the sampling 

agency to take appropriate action, as outlined in Steps 7–10. Microcystin-LR results of 

>1.5 μg/L in a treated supply will result in a resampling of the treated supply as soon as 

possible (Step 9) and notification of the community and appropriate agencies (Step 7). 

Step 7: Notify community and agencies 

Upon receiving the results, the sampling agency will follow standard protocol for 

notifying communities and appropriate agencies. Consideration will be given as to which 

agency should be taking the lead role in this regard. Additionally, the investigation 

should take into account the history of the source/supply and the type of treatment at the 

plant. Dialysis treatment units in the community should also be notified, especially if it is 

a first-time occurrence for blooms on this supply. A Health Canada fact sheet on 

microcystin-LR (It’s Your Health: Blue-Green Algae (Cyanobacteria) and their Toxins) 

is available to help convey information to communities. 

Step 8: Consultation and decision-making 

In the case of community (municipal) supplies, risk assessment discussions should take 

place regarding additional action to be taken. Health agencies, municipal councils and the 

lead regulatory agency responsible for municipal systems should be included in these 

discussions. The risk assessment discussion process should include, for example, such 

items as the history of the site, the size and location of the bloom, available treatment 

technology (if a treated site), uses of the source water (recreational versus domestic uses) 

and monitoring of the environmental conditions that might affect the bloom (e.g., wind). 

Where possible, lysing of the bloom by the addition of copper sulphate or Blue Stone 

should be avoided, as this action will immediately release toxin from the cells into the 

water supply. If the bloom is a common occurrence, nutrient monitoring may be 

considered. Weekly monitoring should be continued. In the case of non-community 

(non-municipal) supplies, the sampling agency will consult with health agencies and 

agencies having treatment expertise.

Note: See Step 10. 

Step 9: Resample treated supply 

Following receipt of results indicating that the treated water contains >1.5 μg 

microcystin-LR/L, the treated supply will be resampled as soon as possible or as 

determined by the sampling agency. 

Step 10: Alternative supply or treatment adjustment 

During the Step 8 decision-making process, discussions regarding treatment adjustments 

or alternative supplies should be reviewed (Step 10). The lead agency should advise the 

owner of the supply of any treatment options, such as additional granular activated 

carbon filtration or ozonation. It should be pointed out that boiling is not effective in 

reducing or removing these toxins, although some point-of-use devices may be effective. 

Note: As blooms may be of short duration (ranging from days to weeks), health and 

environment agencies may recommend, after consultations with the community (see Step 

8), that consumers seek alternative supplies of safe drinking water until there is no longer 

a visible bloom and the toxin level has dropped below 1.5 μg/L. 

63
Step 11 (raw): Microcystin-LR <1.0 μg/L 

A result of <1.0 μg microcystin-LR/L in the raw water will cause the sampling agency to 

continue to visually monitor the raw water for the recurrence of blooms and resample if 

necessary. 

Step 11 (treated): Microcystin-LR <1.5 μg/L 

A result of <1.5 μg microcystin-LR/L in the treated water will cause the sampling agency 

to continue to monitor the raw water as per Step 11 (raw). 

Step 12 (raw): Send results to agencies 

Microcystin-LR results from laboratories (and field test kit results when available) will be

reported to the sampling agency as soon as possible from time of receipt of the sample. 

Sampling agencies are responsible for reporting results to the water supply owner. 

Step 12 (treated): Send results to agencies 

Treated water microcystin-LR results will be reported to the sampling agency as soon as 

possible from the time of the positive raw water results for the same sampling site. 

Sampling agencies are responsible for reporting results to the water supply owner and/or 

responsible agencies.

64
Blue-green algae and their toxins – Great Britain’s perspective 

Huw James, WRc-NSF, Henley Road, Medmenham, Marlow, Bucks. SL7 2HD. 

james_h@wrcplc.co.uk

And 

Anthony Lloyd, Drinking Water Inspectorate, 2/E5 Ashdown House, 123 Victoria 

Street, London SW1E 6DE 

Anthony.Lloyd@defra.gsi.gov.uk

ABSTRACT 

Details of research described in this paper can be found under Foundation for Water 

Research publications at www.fwr.org 

This paper reviews outputs from the United Kingdom’s collaborative research program 

on algal toxins and their significance in drinking water treatment. Information on the 

DWI policy towards control of algal toxins in water supplies and current water industry 

control measures is also given. 

INTRODUCTION 

Blue-green algae in some raw water sources had caused sporadic operational problems, 

such as blockage of raw water filters or the production of tastes and odors in finished 

waters, for water suppliers in the UK for decades. However, in 1989 following well 

publicized blue-green algal blooms, some of which occurred in raw water storage 

reservoirs, it was considered possible that mammalian toxins produced by some of these 

algae could pose a threat to the health of drinking water consumers. The most commonly 

encountered species in the 1989 incidents were Microcystis aeruginosa, Aphanizomenon

sp., Anabaena sp. and Oscillatoria sp. Animal toxicity tests on samples from 78 water 

bodies indicated that 68 percent were toxin producing. 

At this time, there was no reliable information regarding the presence of algal toxins in 

raw or treated waters in the UK, no toxicological information relating to the potential 

route of exposure existed, and it was not known whether water treatment processes then 

in use in the UK were effective in removing toxins (if present) from raw waters. To 

address these deficiencies, a national collaborative research program was initiated in 

1990 by the then Department of the Environment and the National Rivers Authority (now 

the Environment Agency). In 1991 and 1992, contributions to funding were made by UK 

Water Industry Research Ltd. The research program was managed by the Foundation for 

Water Research. 

R&D PROGRAMME (1990-1996) 

This research program had several objectives, as follows: 

65
• development of sensitive analytical methods to allow toxins to be quantified in raw 

water sources and drinking waters; 

• design of a toxicity testing program to establish levels of concern for the toxins; 

• investigation of the effectiveness of various water treatment processes used in the 

production of drinking waters for toxin removal. 

At the time this research began there were several factors that influenced the approach 

that could be adopted. Knowledge concerning the toxins produced by blue-green algae 

was limited, although it was considered that the toxin of greatest relevance to the UK was 

the cyclic heptapeptide hepatotoxin microcystin-LR, so research efforts were initially 

focused on this compound. The fact that it was one of the first hepatotoxins to be 

commercially available was also influential, as pure standards are required to develop 

quantitative analytical methods, to use for toxicity testing and for use in water treatment 

studies. Similar work was also undertaken for the neurotoxin anatoxin-a, which was also 

considered to be of relevance with respect to UK water supplies. 

DEVELOPMENT OF ANALYTICAL METHODS 

It was necessary to develop quantitative analytical methods for toxins in water to 

establish whether they were present in raw waters and drinking waters, to provide a check 

of the dosing levels used in the toxicity testing program and to determine the efficiency 

of removal when various water treatment processes were applied to toxin-containing 

waters. It was also a requirement that the methods developed should be usable on a 

routine basis by water company laboratory staff; this constraint ruled out the use of 

advanced techniques e.g. liquid chromatography-mass spectrometry (LCMS). 

Microcystin-LR

Work on method development commenced in early 1991 and as noted earlier, this was 

one of the then known microcystin congeners that was commercially available. A 

literature survey revealed that although there were several reports of its determination in 

algal cells, little information was available on its analysis in water samples. The 

optimized method developed involved solid-phase extraction followed by analysis using 

high performance liquid chromatography (HPLC) with ultra-violet (UV detection). 

Nodularin, a cyclic pentapetide toxin produced by blue-green algae (Nodularia sp.)

normally found in brackish waters, was used as an internal standard. A limited evaluation 

of the method for drinking waters and reservoir waters in the autumn of 1992 showed that 

at the 1 μg/l level, the relative standard deviation was less than 10%. The method was 

then performance tested by five laboratories in 1993. This involved the analysis of over 

one hundred samples by each laboratory, and demonstrated that the limit of detection was 

0.5 μg/l. 

It was also shown that electrospray ionization LCMS could be used to provide 

confirmatory data. 

66
In 1996 another analytical method, which determined some additional microcystin 

congeners (-RR, -YR) and nodularin, was performance tested. It was shown to be 

satisfactory and could be applied to determine other microcystins, but the lack of 

commercially available pure standards only allowed it to be tested for the aforementioned 

toxins. 

Anatoxin-a

An analytical method for anatoxin-a in water, which involved solid-phase extraction and 

analysis of the extracts using HPLC with UV detection, was developed in 1993. The limit 

of detection of this method was 1 μg/l. In 1994, it was shown that a custom-synthesized 

internal standard (d3-homoanatoxin-a) improved the performance of the method. 

TOXICITY TESTING 

Microcystin-LR

The only published information relating to the toxicity of microcystin-LR that was 

available prior to these studies was that its LD50 via intra-peritoneal (i.p.) injection in 

mice was about 50 μg/kg. The toxicity-testing program, devised in consultation with the 

contract toxicology laboratory that undertook the work, consisted of an acute toxicity 

study to compare the toxicity via the oral and i.p. routes, an investigation of the effects on 

the fetus in the mouse, and a repeat dose study over thirteen weeks by the oral route, 

again in the mouse. The main reason for using the mouse rather then the rat in the latter 

two studies was the availability and cost of pure microcystin-LR. Even when using the 

mouse, the cost of the pure toxin used was over $30,000. 

The mouse oral LD50 in the acute study was found to be about 5000 μg/kg, while the rat 

oral LD50 was greater than 5000 μg/kg. The mouse i.p. LD50 was between 50 and 158 

μg/kg. This meant that the difference in acute toxicity between i.p. injection and oral 

dosing was between 30 and 100-fold, with the mouse being slightly more sensitive than 

the rat. 

The No Observed Adverse Effect Level (NOAEL) for developmental toxicity (daily oral 

administration during organogenesis) was 600 μg/kg bodyweight per day. In the 13 week 

repeat dose study, the clear NOAEL for pathological changes in the liver of the mouse 

when administered orally by gavage once daily was 40 μg/kg bodyweight per day. The 

effects observed at 200 μg/kg bodyweight per day were relatively minor and few animals 

were affected. 

In terms of risk assessment the 40 μg/kg bodyweight per day dose would be 400 times 

greater than that received by a 10 kg child drinking 1 liter of water per day, and the 

margin of safety would be much greater than this. 

67
Anatoxin-a

Toxicity data relating to the acute effects of this neurotoxin were already available, but in 

order to undertake a better-informed risk assessment it was considered necessary to carry 

out some longer-term studies, so a 28-day oral in vivo toxicity study and a developmental 

toxicity screening study were carried out in the mouse. A series of in vitro and in vivo

screening studies were also done in order to properly characterize the pharmacological 

activity of anatoxin-a relative to nicotine (anatoxin-a was known to be a stereospecific 

nicotinic agonist). 

In the pharmacological screening studies anatoxin-a elicited similar responses to those of

standard nicotine solutions, but it was a more potent agonist than nicotine. In a twentyeight day oral repeat dose study the NOAEL found was 0.098 mg/kg bodyweight per day. 

The NOAEL for teratogenicity over the period of organogenesis was 2.46 mg/kg 

bodyweight per day. The conclusion of this latter study (that anatoxin-a was not a 

specific developmental toxicant in the mouse) is in agreement with an earlier study 

carried out in the hamster. 

Based on the most conservative NOAEL from these studies, a guideline value of 1 μg/l 

for drinking water would provide a significant margin of safety of about three orders of 

magnitude for a 10 kg child consuming 1 liter of water per day. 

TREATMENT STUDIES 

Because work already published had shown that conventional water treatment processes 

(chemical coagulation, sand filtration, chlorination) were not particularly effective in 

removing microcystin-LR, advanced water treatment processes were investigated. 

Microcystin-LR

It was shown that activated carbon adsorption, oxidation and nanofiltration could all be 

used to remove this toxin from lowland river-derived reservoir water. Powdered activated 

carbon (PAC) dosing was effective, but the degree of removal was strongly dependent on 

the dose applied and wood-based PAC was more effective than those derived from coal 

or coconut source materials. Coal, peat and wood based granular activated carbon (GAC) 

were also effective in removing microcystin-LR although rapid breakthrough of the toxin 

occurred. 

Ozonation and treatment with potassium permanganate under practicable water treatment 

dosing conditions were the most effective oxidative processes, with higher removal 

occurring when dosed into clarified or sand filtered water. Chlorination (applied chlorine 

dose 1.7 mg/l) was effective, but dependent on pH e.g. at pH5, removal was >90% within 

30 minutes, but at pH7 90% removal was only obtained after 22 hours and at pH9 

removal was even slower. 

68
When using a polymeric nanofiltration membrane with a nominal molecular weight cutoff of 200, and a permeate to retentate ratio of 0.25, complete rejection of microcystin 

occurred and no toxin accumulated on the membrane itself. 

Anatoxin-a

Oxidative processes also removed anatoxin-a, although as for microcystin-LR, they were 

more effective when applied to treated waters. For both ozone and potassium

permanganate, a dose of 2 mg/l gave a reduction of >90 percent in the dissolved toxin 

concentration. However, no significant removal was observed with chlorination. 

PAC and GAC were effective in removing anatoxin-a, although relatively high doses of 

PAC were required to achieve >85 percent toxin removal. Results obtained with GAC 

suggested that for anatoxin-a biodegradation occurs on the GAC. 

OTHER STUDIES 

Monitoring

Since the analytical methods described above were developed, several surveys of raw and 

treated waters have been carried out in England and Wales, and in Northern Ireland. The 

most comprehensive of these surveys was conducted in Northern Ireland to allay 

concerns regarding drinking water produced by a new drinking water treatment works 

taking raw water from a water body where there have been blue-green algal blooms 

(usually Oscillatoria sp.) in the past. A total of two hundred and seventy three samples 

were analyzed during the period June 1998 – July 1999 for microcystin-LR and anatoxina. In one of these samples, anatoxin-a was detected at about 1 μg/l and its presence 

confirmed using GCMS following derivatisation of the extract. This concentration found 

was not considered to be of significance to human health. No microcystin-LR was 

detected in any of the samples. 

Toxin persistence

The analytical methods have also been applied to study the persistence of microcystin-LR 

and anatoxin-a in raw water reservoirs. For microcystin-LR the half-life in reservoir 

water was found to be about six days, and with addition of bed sediment this was reduced 

to about 3 days. The half-life of anatoxin-a was found to be 4-5 days in reservoir water at 

pH8 in the presence of bed sediment. At pH4, anatoxin-a is persistent but as it is unlikely 

that natural waters at this pH would support populations of anatoxin-a producing bluegreen algae, this finding was not considered significant. 

GUIDELINES AND STANDARDS FOR ALGAL TOXINS 

The water industry in England and Wales was privatized in 1989 and the Government’s 

technical regulator for the industry is the Drinking Water Inspectorate (DWI). The Water 

Supply (Water Quality) Regulations (1989), which DWI enforces, cover some 55 specific 

69
parameters that do not include algal toxins. However, the regulations require that no 

substance may be present in drinking waters at concentrations that would cause a risk to 

health. In this respect water utilities would be required to monitor for algal toxins, if a 

risk situation existed. In the UK, water utilities currently base that risk assessment on the 

potential for algal loadings to overwhelm treatment processes and contaminate supplies. 

In respect of regulatory standards, there are insufficient data to determine health-based 

guidelines or standards for even a representative selection of the toxins. The best studied 

is microcystin LR, although uncertainties exist, particularly with regard to its tumor 

promoting capability. Guideline values have only been set for microcystin 

LR/microcystins. WHO proposed a provisional guideline value in 1998 for microcystin 

LR and Health Canada set a guideline value for microcystins at about the same time. 

Both of these were based on the data generated by the UK national research program. 

Some data have been generated for anatoxin-a that provides sufficient information to give 

a reasonable level of reassurance regarding the concentrations encountered in UK waters. 

Data on cylindrospermopsin have been recently produced in Australia but these data have 

a number of problems with regard to reporting and interpretation. It is understood that 

WHO will consider the data in the rolling revision of its Guidelines for Drinking Water 

Quality. There is pressure from some of the groups working on toxins to produce 

“standards” for toxins but reports from WHO indicate that this is not seen as an 

appropriate approach. 

At the Global Meeting on the WHO Guidelines in Tokyo in May 2002, there was 

considerable discussion of blue-green algae and their toxins. The general view was that 

toxic blooms need to be taken seriously. There was particular concern in parts of Asia, 

where there can be significant growths throughout the year. The main issue is clearly one 

for developing countries where there are many small, under-resourced, supplies with only 

basic treatment. It was generally agreed that a preventative approach is preferred and that 

any attempt to control the risk by routine monitoring for toxins was not practicable. 

Analytical methods are complicated and not sufficiently robust for routine monitoring 

purposes. Standards are very expensive and are available for only a few toxins. In 

addition, there are almost certainly a number of as yet unidentified toxins. 

Currently, setting a standard based on the few toxins for which there were adequate data 

could be construed as potentially misleading because the absence of a particular toxin 

does not indicate the absence of a problem. In addition, the potential for changes in the 

presence and absence of toxins means that sampling to give an appropriate level of 

reassurance could be problematical. Prevention of blooms forming is the best way 

forward, although this may present some difficulties. Control of eutrophication is an 

important issue for the Environment Agency in the UK and at the European level; it will 

be an important consideration in the Implementation of the Water Framework Directive. 

It is understood that the WHO approach will be supported by guidelines for some toxins, 

developed when there are adequate data but the production of guideline values for an 

70
increasing list of toxins is seen as potentially counter-productive. The WHO paragraph to 

be included in volume 1 of the revised guidelines currently reads as follows: 

Cyanobacteria occur widely in lakes, reservoirs, ponds and slow flowing rivers. Many 

species are known to produce toxins, a number of which are of concern for health. There 

are many cyanotoxins, which vary in structure and may be found within cells or released 

into water. There is wide variation in the toxicity of recognized toxins (including amongst 

different varieties of a single toxin, e.g., Microcystins) and it is likely that further toxins 

remain unrecognized. 

The health hazard is primarily associated with overgrowth (bloom) events. Such blooms may 

develop rapidly and they may be of short duration. In most circumstances, but not all, they are 

seasonal. 

Analysis of these substances is also difficult although rapid methods are becoming 

available for a small number, e.g, microcystins, in addition analytical standards are 

frequently not available. The preferred approach is, therefore, monitoring of source 

water for evidence of blooms, or bloom forming potential, and increased vigilance where 

such events occur. 

A variety of actions are available to decrease the probability of bloom occurrence and 

some effective treatments are available for removal of cyanobacteria or cyanotoxins. For 

these reasons, monitoring of cyanotoxins is not the preferred focus of routine monitoring 

and is primarily used in response to bloom events. Whilst guideline values are derived 

where sufficient data exist, they are intended to inform the interpretation of data from the 

above monitoring and not to indicate that there is a requirement for routine monitoring 

by chemical analysis. 

OPERATIONAL ISSUES IN THE UK 

Because of the comprehensive treatment processes that are already in place at water 

treatment works, monitoring for algal toxins is normally only undertaken when there is a 

risk that algal cell concentrations could adversely affect treatment processes. Algal 

blooms occur seasonally in many impounding reservoirs where water is abstracted from 

lowland rivers. These rivers drain agricultural catchments and there are usually 

significant inputs of treated sewage effluent. Although phosphate removal is practiced at 

some locations, this treatment rarely achieves the overall reduction in phosphorus input 

needed to limit development of algal blooms. 

Operational measures focus on forced mixing/aeration systems. These are aimed 

primarily at avoiding stratification but also limit algal growth by reducing light 

penetration. Multiple draw-off levels are used to facilitate selection of best quality water 

and where alternative sources are available, continuous fluorimetry is used to enable 

switching of sources to reduce algal load in raw water. Monitoring of reservoirs is 

normally carried out from boats, with samples taken throughout the water column. 

Measurements include: a-chlorophyll, particulate organic carbon, algae identification and 

71
estimation of abundance and inorganic algal nutrients. These data are assessed in the light 

of potential to cause blocking of filters and no water utilities carry out routine analysis for 

algal toxins. 

Public access is permitted on many lowland reservoirs and contact water sports are 

commonly practiced. Livestock grazing to the water’s edge is rarely allowed but dogs and 

horses may drink from reservoirs, especially where footpaths and bridleways border the 

reservoir. Where access to reservoirs is permitted, warning signs alert the public to the 

risk of contact with water, or allowing animals access to the water. These signs are 

usually permanently installed, rather than being deployed only when an algal bloom is

underway. 

CONCLUSIONS 

The comprehensive R&D program that was funded by the UK government and the water 

industry addressed the potential threat to drinking water supplies from blue-green algal 

toxins. The research outputs have enabled a better understanding of the problems posed 

by these toxins and the ways in which the potential risks can be effectively addressed. 

The main part of this program was conducted over the period from 1991-1996 and the 

cost to the funding bodies was in excess of 1.5 million dollars. 

 

In the UK, there have been relatively few problems relating to blue-green algal toxins and 

drinking waters since 1989, and there was only a limited demand for monitoring for 

microcystins and anatoxin-a during the period 1992-1996. The only significant 

monitoring that has been undertaken since was for water samples from Northern Ireland 

between June 1998-July 1999. A further indication of the lack of demand for monitoring 

is illustrated by the fact that with one exception (WRc-NSF), no contract laboratories 

currently offer the analysis of blue-green algal toxins. 

Most lowland waters in the UK receive multiple barrier treatment, often including ozone 

and/or carbon treatment. The national research program provided reassurance that, as 

long as algal loadings are not allowed to overwhelm treatment, exposure to algal toxins 

via drinking water would not constitute an identifiable risk to health. This situation could 

of course change if water temperatures and nutrient inputs continue to increase. 

The main potential problem for the UK water industry at present concerns disposal of 

filter backwash water from those water treatment works which experience significant 

algal blooms in their raw water storage reservoirs. The Environment Agency is actively 

seeking to place discharge consents on the disposal of such waters (particularly where 

there is little dilution by the receiving waters), although no consents have yet been 

applied. 

72
Summary of: WHO Guidelines 

Presented by: Ian Falconer, D.Sc. 

Dr. Ian R. Falconer, from the Cooperative Research Center for Water Quality and 

Treatment and the University of Adelaide Medical School, gave an additional 

presentation on the World Health Organization (WHO) and their approach to 

cyanobacterial toxin guidelines. WHO drinking water guidelines, based on potential 

hazards to human health, were first released in 1985, and have undergone numerous 

revisions. Cyanobacterial toxins were considered as part of the WHO drinking water 

guidelines in April 1997, following the production of a WHO monograph on the subject. 

The group that produced the monograph recommended that a Guideline Value of 1 

microgram per liter be made for microcystin, based largely on animal and human data 

from Australia. 

Dr. Falconer discussed research, much of which was his own, on microcystin. The 

tolerable daily intake (TDI) was determined from 10-13 week oral dosing tests in mice 

and pigs. The NOAEL in mice was 40 μg/kg/day, and the LOAEL in pigs was 100 

μg/kg/day. The TDI was created by dividing the NOAEL in mice, 40 μg/kg/day by three 

ten-fold safety factors, yielding 0.04 μg/kg/day. The WHO then generated a guideline 

value by multiplying the TDI by a 60 kg body mass and a 0.8 proportion of dose due to 

drinking water and dividing by 2.0 L/day water consumption. This yields 0.96 μg/L, or 

roughly 1.0 μg/L. 

As Dr. Falconer mentioned, the Chemical Substances Working Group reviewed the 

matter of cyanobacterial toxins in May of 2002. The Toxic Cyanobacteria in Water 

monograph, originally written in 1997, is to be revised and reissued. The WHO will 

reconsider cylindrospermopsin, for which an oral toxicity study was completed, and other 

cyanobacterial toxins in 2003/4. In light of actions by the WHO, Australia, Canada, New 

Zealand, Poland and Brazil have established a guideline for microcystin, and have 

provisional standards for other cyanobacterial toxins. Lastly, monitoring and water 

treatment techniques are being improved, and attentiveness to cyanobacterial toxins is 

rising. 

73
Laboratory Methods for the Study of Harmful Cyanobacteria Water blooms: 

“The Cyano-HABs” 

Wayne W. Carmichael 

Professor-Aquatic Biology/Toxicology 

Department of Biological Sciences 

Wright State University 

Dayton, Ohio 45435 U.S.A. 

Tel: 937-775-3173 

Fax: 937-775-3320 

E-mail: wayne.carmichael@wright.edu

University website address: 

http://biology.wright.edu/faculty/carmichael/labhome.htm

Background 

Increasingly, harmful algal blooms (HABs) are being reported worldwide due to several factors, 

primarily - eutrophication, climate change and more scientific investigation (Hallegraeff et al., 1995). 

HAB organisms include those causing: PSP (paralytic shellfish poisoning), DSP (diarrhetic shellfish 

poisoning), NSP (neurotoxic shellfish poisoning), ASP (amnesic shellfish poisoning) and CTP 

(cyanobacteria toxin poisoning). All but CTP organisms are mainly a marine occurrence. CTPs occur 

in freshwater lakes, ponds, rivers and reservoirs throughout the world. Organisms responsible include 

an estimated 40 genera but the main ones are Anabaena, Aphanizomenon, Cylindrospermopsis, 

Lyngbya, Microcystis, Nostoc and Oscillatoria (Planktothrix) (Carpenter and Carmichael, 1995). 

Cyanobacteria toxins (cyanotoxins) include cytotoxins and biotoxins with biotoxins being responsible 

for acute lethal, acute, chronic and sub-chronic poisonings of wild/domestic animals and humans. The 

biotoxins include the neurotoxins; anatoxin-a, anatoxin-a(s) and saxitoxins plus the hepatotoxins; 

microcystins, nodularins and cylindrospermopsin (Carmichael, 1997; 2001) (Table 1). 

Table 1. Name and Producer Organism for the Biotoxic Cyanotoxins 

------------------------------------------------------------------------------------------------------------ 

 NAME PRODUCED BY 

------------------------------------------------------------------------------------------------------------ 

Neurotoxins 

 

 Anatoxin-a Anabaena, Aphanizomenon, Oscillatoria 

Homo-Anatoxin-a (Planktothrix)

 Anatoxin-a(s) Anabaena, Oscillatoria (Planktothrix)

Paralytic Shellfish Poisons 

74
 (Saxitoxins) Anabaena, Aphanizomenon, Cylindrospermopsis, 

 Lyngbya, Planktothrix, Trichodesmium, 

Liver Toxins 

Cylindrospermopsin Aphanizomenon, Cylindrospermopsis, 

Rhaphidiopsis, Umezakia

Microcystins Anabaena, Aphanocapsa, Hapalosiphon, 

Microcystis, Nostoc, Oscillatoria (Planktothrix), 

Synechococcus 

 Nodularins Nodularia (brackish water) 

Contact Irritant-Dermal Toxins 

 Debromoaplysiatoxin, 

 Lyngbyatoxin Lyngbya (marine)

 Aplysiatoxin Schizothrix (marine) 

Concern for animal and human health impairments due to toxic cyanobacteria arises from

several sources of information. The main one concerns reports of animal poisonings from

ingestion of toxic water blooms beginning with the later part of the 1800's. It was not 

until the 1950's, with pioneering work of scientists in Canada, the United States, 

Australia and South Africa, that we began to understand that cyanobacteria could indeed 

produce highly toxic compounds. The animal and human intoxication reports were first 

summarized in the 1960's by Schwimmer and Schwimmer (1964, 1968). These reports 

have been updated by several works including Sivonen (1990), Carmichael (1992), 

Ressom, et al. (1994) and Yoo, et al. (1995). In addition, a major effort to compile all 

available information on toxic cyanobacteria including issues of human health, safe water 

practices, management, prevention and remediation has been published by the World 

Health Organization (Chorus and Bartram, 1999). This book is designed as a manual for 

water and health authorities in addressing all issues of toxic cyanobacteria that they may 

be confronted with. 

Along with the WHO manual came a study on the risk assessment of cyanotoxins in 

drinking and bathing waters. Risk assessment of microcystins (as Microcystin-LR) 

indicate that a level of 1 μg L-1 should be considered a guideline value for maximum 

allowable concentration (MAC) based upon an adult consumption of 2 L day-1. Other 

MAC's for the neurotoxins and cylindrospermopsin will not be set until more basic 

toxicology and epidemiology are available. In addition, the State of Oregon in the U.S.A. 

has set a regulatory level of 1 μg g-1 for microcystins (as Microcystin-LR) in human food 

supplements made from the filamentous cyanobacterium Aphanizomenon flos-aquae

(AFA). In this case the AFA is not the producer of microcystin but because it is harvested 

from a natural lake (Klamath Lake), other cyanobacteria present as a normal part of the 

75
harvested algae (i.e., Microcystis aeruginosa a known producer of microcystins) are the 

source of this hepatotoxins. Health authorities from several countries are also evaluating 

the risks of cyanotoxins in algae and may also adopt guideline or regulatory levels for 

microcystins in drinking and recreational waters and algae food products. 

Confirmation of human deaths from cyanotoxins is limited to exposure through renal 

dialysis. Microcystins were implicated as the major contributing factor in liver failure and 

death of at least 52 humans, in 1996, at a haemodialysis center in Caruaru, Brazil 

(Jochimsen, et al. 1998, Carmichael, et al. 2001). This tragic but avoidable event points to 

the importance of understanding cyanotoxins as health hazards in drinking waters and

then communicating this information, including the correct identification of 

cyanobacteria responsible for poisonings, to water authorities and public health officials. 

Since most of the worlds reservoir and lake based water supplies are subject to increasing 

nutrient levels, it is probable that episodes of cyanotoxin poisoning will continue unless 

measures are taken to improve our understanding of their role in water-based diseases. 

For these reasons it is important to consider the prevention, management and mitigation 

of CyanoHABs. 

Prevention, Management and Mitigation Strategies for Control of Cyanobacteria 

and Their Toxins 

The first goal in the control of cyanobacteria water blooms in public water supplies 

should be the implementation of ways to prevent or at least minimize those conditions, 

which lead to their excessive growth. In addressing these growth requirements the two 

main problems are nutrients and light (Chorus and Bartram 1999-Ch. 8). Critical to 

nutrient and light control is proper management of the water supply watershed and the 

water reservoir. There are two main ways this can be done. They are termed ‘top-down’ 

and ‘bottom-up control’. Top down control is also termed bio-manipulation and is the 

management of higher trophic organisms to maximize grazing of algae and thus reduce 

cyanobacteria abundance. The bottom-up approach is to restrict the supply of essential 

nutrients and thus restrict growth. The key action for nutrient control of cyanobacteria is 

reduction of external phosphorus and nitrogen. In this argument, bottom-up control is 

extended to include the restriction to supply of all resources. Therefore, the manipulation 

of the light climate by artificial mixing is also included in bottom-up control. 

The management of cyanobacteria water blooms is best approached by the development 

of a risk-management framework. This framework should define the needed approaches 

for situation assessment, management actions (often referred to as the Alert Levels 

Framework), and appropriate planning and response (Chorus and Bartram 1999, Ch. 6-7). 

The mitigation, or minimization, of the harmful effects of a cyanobacteria water bloom 

can be approached in three main ways (Chorus and Bartram 1999-Ch. 9). The first 

involves selecting the best abstraction method or location for bringing water into the 

treatment plant. This can be done by choosing an optimum position for off take, or by 

abstracting surface water through bank or ground filtration. The second major way to 

mitigate cyanobacteria water blooms is to choose the optimum water treatment 

76
technique(s) in the water treatment plant. These include the proper choice of coagulation, 

precipitation, sedimentation, filtration and adsorption technologies for water bloom

management. The third and final way to mitigate cyanobacteria water blooms is with 

chemicals. 

Chemical control of algae in water supply storages has been a widespread water quality 

mitigation practice for over 100 years. Copper sulphate has generally been the algaecide 

of choice and records of its use date from 1890 in Europe (Sawyer 1962), 1904 in the 

U.S. (Moore and Kellerman 1905), and since at least the mid-1940’s in Australia (Burch 

et al. 2001). 

An extensive survey of water utilities in the U.S. and Canada in the 1980's indicated that 

copper sulphate is by far the most widely used algaecide, although other alternatives are 

used under some circumstances (Casitas Municipal Water District 1987). A summary of 

the range of compounds that have been used as algaecides is given in Table 2. 

TABLE 2: Common algaecides and their formulations (after Burch et al., 1998)

COMPOUND FORMULATION 

Copper sulphate CuSO4.5H2O 

Copper II alkanolamine 

complex

Cu Alkanolamine .3H2O++ 

Copper - ethylenediamine 

complex 

[Cu(H2NCH2CH2NH2)2(H2O)2]

++ SO4

Copper - triethanolamine 

complex 

Cu N(CH2CH2OH)3.H2O 

Copper citrate Cu3[(COOCH2)2C(OH)COO]2

Potassium permanganate KMnO4

Chlorine Cl2

Lime Ca(OH)2

Barley straw

In summary, for mitigation of cyanobacterial water blooms the first priority should be

removal of intact cells, using selected abstraction points followed by separation 

techniques such as coagulation or membrane filtration. Chemical treatment methods have 

and are being evaluated with chlorination and ozonation being effective for the 

destruction of residual dissolved microcystins and cylindrospermopsin at moderate water 

temperatures. Possible temperature effects on these oxidation reactions are currently 

unknown. Anatoxin-a can be effectively removed using ozone, although chlorine is 

relatively ineffective. Oxidation techniques do not appear to be the best method for the 

treatment of saxitoxins under normal treatment plant operating conditions. Powdered 

77
activated carbon can be effective for the removal of all toxins, except, perhaps, a few 

microcystins, provided the appropriate carbon, and the correct dose is applied. Granular 

activated carbon filters show a limited lifetime for the adsorption of most 

microcontaminants, including cyanotoxins. The biodegradation of cyanotoxins across 

GAC filters shows great potential as a treatment process. 

Laboratory methods for the Study of Harmful Cyanobacteria Water blooms 

In order to effectively study CyanoHABs, it is necessary to consider several distinct areas 

including: 

• Ecology and Physiology of Cyanobacteria Water blooms 

• Sampling, Identification (Taxonomy) and Quantification of Cells 

• Culture and Handling of Toxic Cells 

• Preparation and Processing of Cells, Tissues and Other Matrices for Toxin 

Analyses 

• Cyanotoxin Detection and Analyses Methods 

- Biological – Bioassay 

- Biochemical - i.e. Immunological (ELISA); Enzyme (PPIA) 

- Analytical - HPLC, MS, NMR 

- Genetic – PCR and others 

Laboratory studies focus on the latter four areas and our laboratory work has emphasized 

the last topic area-detection and analyses of cyanotoxins. 

Over the past 30 years these studies have involved: 

- Biological - Bioassay 

* Small animal - mouse, invertebrate LD and LC50 

* Microbial 

- Biochemical - i.e. Immunological (ELISA); Enzyme (PPIA); Cell Receptor 

- Analytical - HPLC, MS, NMR 

78
- Genetic – PCR 

* 16S rRNA 

* nifH (gene for dinitrogen reductase-N2 fixation) 

* cpcBA, IGS (intergenic spacer region between two phycobilisome subunits), 

* MCY (microcystin gene) 

* Other toxin genes (CYN, Antx-a) are being studied 

Recent Methods for Analyses of Microcystins 

A current method used in our laboratory for extraction and analyses of Microcystins is 

given in Fig. 1. 

Fig. 1. Flow diagram for extraction and analyses of Microcystins. 

Sam p le (Ce lls, o r o the rs)

S upe rn a tant

E x tra c tion w ith 5% H O A c aq.

or M eO H

Pa ss th ro u gh O D S (o r H LB )

colum n (c a rtridge )

ODS (o r HLB) colum n

W a sh w ith w a te r

E lu te w ith M eO H

T oxin fra c tio n

LC/M S an a lysis

SELD I-T O FM S

D ire ct an alysis

P u re to xin

H P LC spa ra tio n

Sam p le (Ce lls, o r o the rs)

S upe rn a tant

E x tra c tion w ith 5% H O A c aq .

or M eO H

Pa ss th ro u gh O D S (o r H LB )

colum n (c a rtridge )

ODS (o r HLB) colum n

W a sh w ith w a te r

E lu te w ith M eO H

T oxin fra c tio n

LC/M S an a lysis

SELD I-T O FM S

D ire ct an alysis

P u re to xin

H P LC spa ra tio n

79
LC/MS and MS/MS are done using an LCQ quadropole ion-trap mass spectrometer 

(Thermoquest, USA). The mass spectra are obtained using direct infusion or flow injection 

with MeOH/H2O (1:1) mobile phase. The positive or negative ESI mode is used. For 

microcystins collision energy of 35-40% for MS/MS is used. Figure 2 shows the typical 

LC/MS conditions for microcystins. 

Fig. 2. LC/MS Conditions for Analyses of Microcystins 

LC conditions

Mobile phase:

ACN/0.02%HFBA H2O/0.02%HFBA

or CAN/0.05%TFA H2O/0.05%TFA

Column:

C18 (3μ, 050x020, MetaChem)

or SYMMERY C8 (3.5μ, 100x021, Waters)

Gradient conditions:

0-1 min: 20% organic

2-7 min: 60% organic

7.1-15 min: 20% organic

Flow rate:

0.2 ml/min.

MS conditions

Positive or negative ESI

Source voltage: 5.0kV

Capillary temperature: 250oC

80
Using these conditions microcystin-LR can be detected on column, in the positive mode, at 

less than 10 pg (Fig. 3). 

Fig. 3. Chromatogram of 15.6 pg microcystin-LR on column (3μ C18). 

RT:0.00 - 15.00 SM: 7G

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Time (min)

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

Relative Abundance

RT: 8.24

MA: 65859

MH: 10271

BP: 995.43

NL: 1.03E4

Base Peakm/z=

994.5-995.5 F:+ c ESI

Full ms2

995.50@20.00 [

995.00-996.00] MS 

LRcurve_8

81
We have developed a rapid and efficient method to analyze microcystins/nodularins 

using surface-enhanced laser desorption ionization-time-of flight mass spectrometry 

(SELDI-TOFMS) with Ciphergen protein chip reader system. SELDI-TOFMS is a novel 

approach that was introduced by Hutchens (Hutchens 1993). This technique retains the 

target compounds on a solid-phase chromatographic surface (chip), subsequently ionized 

by laser and detected by TOFMS. The chip system with SELDI-TOF MS allows for 

peptide and protein analysis with high sensitive from a variety of complex biological 

materials such as cell, serum, blood, plasma, and tissue, et al., with limited sample 

preparation (Jssaq 2002). 

SELDI-TOF MS analysis was carried out using the Ciphergen protein chip system

(Ciphergen, Palo Alto, CA). Ciphergen Protein Chip Software 3.0 was used. The analysis 

procedure was adapted from the Ciphergen users guide with the following modifications. 

Two μL of sample diluted in distilled water were applied to the spot on the chip and 

allowed to air dry. This was followed by washing with 3 μL of distilled water and 

allowed to dry. To the dry spot, 0.7 μL of Energy Absorbing Molecule (EAM) was 

added. The sample chip was transferred to the chip reader and analyzed following 

desorption of the bound target by short intense probes from an N2 320 nm-UV laser. The 

mass spectra were determined by time-of-flight in a mass spectrometer. 

An example of the results for SELDI-TOF mass spectra of microcystins-LR, -YR, -RR 

and Nodularin are shown in Figure 4. 

Figure 4. SELDI-TOF mass spectra of microcystins-LR, -YR, -RR and Nodularin. Chip: 

H4. Sample 

concentration: 1

μg/mL each. 

Sample 

volume: 2 μL. Laser 

intensity: 190. EAM 

concentration: 30%

saturated 

CHCA 

solution 

82
SELDI-TOF MS has also been used in our laboratory to analyze microcystin bound to the 

protein phosphatase enzyme complex. This is useful in allowing the time course of 

microcystin binding to be observed in vitro. 

These and other methods being developed in our laboratory and others around the world 

will provide new techniques for observing not only microcystins but also other 

cyanotoxins in environmental matrices. Results obtained from these methods will help 

document the growing incidence of cyanotoxins in water based disease and provide the 

basis for water management techniques designed to improve water quality in order to 

minimize the human and animal health impacts from CyanoHABs. 

Acknowledgements 

Past and present work on CyanoHABs has involved many students, staff and colleagues. 

The following agencies and persons supported the work summarized in this paper: 

• Florida (Funding sources)-FMRI and SJWMD through FMRI 

• Wright State Univ.-Charles Friday, Jerome Servaites, Moucun Yuan, John Blakelock, 

Jennifer Ott, Laurel Carmichael

• UNC-IMS-Hans Paerl and crew 

• Canada-E.A.D. Allen 

• Univ. Illinois-Ken Rinehart-NIH Subcontract 

• Australia-NRCET-Glen Shaw, Geoff Eaglesham

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Jochimsen, E.M., Carmichael, W.W., An, J.S., Cardo, D.M., Cookson, S.T., Holmes, 

C.E.M., Antines, M.b. de C., Filho, D.A. de Meb, Lyra, T.M., Burreto, V.T.S., 

Azevedo, S.M.F.O. and Jarvis, W.R. 1998. Liver Failure and Death Following 

Exposure to Microcystin Toxins at a Hemodialysis Center in Brazil. New Eng. J. 

Medicine. March 26, 1998, V. 338(13): 873-878. 

Moore, G.T., Kellerman, K.F. 1905. Copper as an Algaecide and Disinfectant in Water 

Supplies. Bull. Bureau Plant. Indus. U.S.D.A. 76: 19-55. 

Ressom R., Soong, F.S., Fitzgerald, J., Turczynowicz, L., Saadi, O.E., Roder, D., 

Maynard, T., Falconer, I. (eds.) 1994. Health Effects of Toxic Cyanobacteria 

(blue-green algae) National Health and Medical Research Council, Australian 

Govt. Pub. Service, Canberra. 

Sawyer, C.N. 1962. Causes, Effects and Control of Aquatic Growths. J. WPCF. 34: 279- 

288. 

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Sivonen,K. 1990. Toxic Cyanobacteria in Finnish Fresh Waters and the Baltic Sea. Ph.D. 

Academic Dissertation in Microbiology, University of Helsinki, Finland. 

Schwimmer, D., Schwimmer, M. 1964. Algae and Medicine. in Algae and Man. D.F. 

Jackson (ed.) Plenum Press, New York, pp. 368-412. 

Schwimmer, D., Schwimmer, M. 1967. Medical Aspects of Phycology. in Algae, Man 

and the Environment. D.F. Jackson (ed.) Syracuse University Press, pp. 279-358. 

Yoo, R.S., Carmichael W.W., Hoehn, R.C., Hrudey, S.E. (eds.) 1995. Cyanobacterial 

(Blue-green Algal) Toxins: A Resource Guide 229 pp. AWWA Research 

Foundation and American Water Works Association, Denver. 

85
CYANOBACTERIA TOXINS: 

Florida Department of Health, Bureau of Laboratories Activities 

James E. Evans, Ph.D. 

Marek Pawlowicz, Ph.D. 

History of cyanobacteria toxin testing at the Department of Health, Bureau of Laboratories 

Bureau of Laboratories involvement in cyanobacteria testing began soon after the 

creation of the Florida Harmful Algal Bloom Task Force (HABTF) in 1998. In response 

to a HABTF Technical Advisory Group report identifying cyanobacteria as a research 

priority, the St. John’s River Water Management District (SJRWMD) initiated a 

collaborative study to characterize and identify algal toxins in Florida’s surface waters. 

Participants in this study included the SJRWMD, Wright State University, the Florida 

Department of Health, the Florida Marine Research Institute, and the Florida Fish and 

Wildlife Conservation Commission. The survey of Florida’s surface waters was 

conducted in 1999. This survey was followed up the following year with a monitoring of 

surface waters identified in the 1999 survey, selected water treatment plants, and bloom

events. 

The Florida Department of Health, Bureau of Laboratories Environmental Microbiology

Unit – Jacksonville, performed enzyme linked immunosorbent assays (ELISA) for 

microcystin and mouse bioassays for general toxicity in support of the initial surveys as 

well as the follow-up studies. The findings of these studies are undoubtedly documented 

elsewhere in this series of monographs and will, therefore, not be repeated. However, the 

cumulative findings led the Department of Health to a decision that cyanobacteria toxins 

were an issue requiring further investigation from a public health perspective. To 

adequately support future public health investigations, it was determined that laboratory 

capabilities needed to be expanded to allow for more comprehensive and quantitative 

analyses. To this end, funding for the enhancement of laboratory capacity was sought 

and obtained via supplemental funding from a CDC/Florida Cooperative Agreement 

(Pfiesteria-Related Illness Surveillance and Prevention Grant #U50/CCU415409-04). 

Selection and implementation of new analytical methodology 

In the selection of analytical instrumentation to enhance and expand current laboratory 

capabilities, the Bureau of Laboratories had a number of needs in mind. The first was to 

expand capabilities to include other toxins of interest beyond the microcystins. There 

was also a desire for more sensitive, specific, and reproducible techniques with 

methodologies that could identify and quantitative multiple analytes/analogs in a single 

analytical run. Finally, with considerations for the future, it was desired that any newly 

acquired capabilities conform to accepted practices and be adaptable to potential 

monitoring and regulatory programs. 

ELISA has distinct advantages in that procedures are relatively straightforward and that 

assays are available in commercial kit form. In addition, ELISA methods can prove to be 

very sensitive, however, such claims are often not demonstrated in routine use. ELISA 

86
methods are also often plagued by analog cross reactivity. Such non-specificity may or 

may not be well characterized, complicating the interpretation of results. Reproducibility 

is also a problem with ELISA assays as they are highly dependent on technique and the 

extent of sample preparation required. While ELISA has proven itself as a valuable 

screening assay, the laboratory sought to move toward a more quantitative analytical 

approach. 

The mouse bioassay has also proven to be a valuable screening tool for general toxicity 

of water containing cyanobacteria toxins. However, the assay is inherently non-specific 

and may be complicated by other unknown contaminants in a given water sample. It is 

also a non-quantitative assay, having proven to be difficult to correlate with the amount 

or type of toxin present. There are also concerns with cost, ethics, and relevance to 

human toxicity that limit the mouse bioassay’s utility. 

Given the limitation of the past screening assays used and in consideration of the outlined 

needs, the laboratory chose an analytical instrument system that provided a 

comprehensive solution. The system is comprised of high performance liquid 

chromatography with multiple detection components. Both photo diode array and 

fluorescence detectors as well as a mass spectrometer will be available to offer a wide 

range of capabilities for the detection of the various cyanobacteria toxins. Such a 

multiple detector set-up was designed to allow for the analysis of toxins by the currently 

accepted analytical methodology as well as for the development of techniques to 

determine multiple toxins and their analogs within the same analytical run. This system

provides specific, sensitive, quantitative, and reproducible analytical capability that was 

lacking with the screening assays. There are limitations in that standard control material 

must be available to properly quantitate a given toxin, however, such standards are 

becoming more readily available as interest and research in the field advances. An 

additional limitation that bears mention, as with any quantitative technique for the 

cyanobacterial toxins, is that the relationship between concentration and human health 

effects is unknown. 

Future plans 

While the immediate plans for the Department of Health, Bureau of Laboratories focuses 

around implementing the HPLC analysis system previously described, other ongoing 

laboratory activities will allow for the investigation of other assay and analytical 

techniques. Alternate analytical techniques such as gas chromatography - mass 

spectrometry (GC-MS), and liquid chromatography – tandem mass spectrometry (LCMS/MS) are available for examination of applicability to toxin analysis. In addition, 

bioassay and molecular analyses currently in use in other public health initiatives within 

the laboratory allow the possibility of applying these techniques as well. 

In addition to the investigation of other assay and analytical methodologies, the addition 

of laboratory capabilities allows for the assumption of projects to consider the various 

public health implications of cyanobacteria toxin exposure. One such study supported by 

the CDC/Florida DOH Cooperative Agreement (Pfiesteria-Related Illness Surveillance 

and Prevention Grant #U50/CCU415409-04) is a study designed to determine the 

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effectiveness of home filtration devices in the removal of cyanobacteria toxins from

potable water. This study will seek to identify filter matrices that are effective in the 

removal of different cyanobacteria toxins. It is expected that the ability of a given filter 

type to effectively remove toxin will be dependent upon such variables as the type of 

toxin, filter composition, filter design, filter capacity, filter size, and water quality to 

name just a few. The results of this study could provide a basis for advising consumers 

how to prevent or minimize exposure to cyanobacteria toxins in the absence of standards 

or scientific evidence of actual health risks. 

Conclusions

In conclusion, the Department of Health Laboratory is expanding capacity and capability 

to perform analyses for cyanobacteria toxins. The laboratory is committed to working 

with public health partners to address issues surrounding cyanobacteria toxin exposure 

and possible links to human health effects. 

The laboratory wishes to acknowledge the CDC/Florida Cooperative Agreement 

(#U50/CCU415409-04), the Florida Harmful Algal Bloom Task Force, and the 

Department of Health, Division of Environmental Health, Bureau of Environmental 

Epidemiology for their support. 

The authors also wish to acknowledge work and dedication of the staff of the 

Environmental Microbiology Laboratory, Environmental Chemistry Laboratory, and the 

entire Florida Department of Health, Bureau of Laboratories in their continued efforts to 

protect public health by providing diagnostic screening, monitoring, reference, 

emergency, and research laboratory services. 

88
Current EPA Work on Algal Toxins in Drinking Water 

James L. Sinclair 

Office of Ground Water and Drinking Water 

U.S. EPA

Cincinnati, OH 

The Safe Drinking Water Act Amendments (SDWA) of 1996 (PL 104-182) authorizes 

regulation of previously unregulated drinking water contaminants in public water 

systems. This act requires that a list of contaminants (Contaminant Candidate List, or 

CCL) to be considered for regulation be published 18 months after enactment of the 

SDWA (1998) and every 5 years thereafter. Contaminants placed on the list are not 

currently regulated, are known or thought to occur in public water systems, and may 

require regulation. At least five contaminants are required to be considered for regulation 

every 5 years. Contaminants may be regulated if they have an adverse health effect on 

people, are known to occur or there is a substantial likelihood that they will occur in

public water systems, and regulation presents a meaningful opportunity for health risk 

reduction in people served by public water systems. 

The Federal Register notice announcing the Contaminant Candidate List (63FR10274) 

includes a list of research topics where sufficient information is required to make a 

regulatory determination on contaminants. These topics include health effects of 

contaminants, control of contaminants by drinking water treatment, occurrence in water, 

and analytical methods that are used to get occurrence information. Specific 

contaminants are listed as needing research in one or more of these areas before a 

regulatory determination can be made. For algae and their toxins, research is needed on 

health effects, treatment, occurrence and analytical methods. 

The research that is needed to make regulatory decisions may be done through research 

organizations that include research facilities of the EPA. Additionally, in the case of

contaminant occurrence, occurrence information may be gotten from surveys carried out 

by these research organizations or it may also be gotten from a public water supply 

monitoring regulation, the Unregulated Contaminant Monitoring Rule (64FR50555, 

Scharfenaker, 2001). The UCMR requires that certain public water supplies monitor for 

selected contaminants for one year or less, depending on the monitoring option used. The 

contaminants to be monitored under the UCMR are picked from the CCL. The UCMR 

monitoring list is revised every 5 years on a schedule where it is published one year later 

than the CCL. The first UCMR monitoring list was published in 1999, and the second 

UCMR list will be due in 2004. 

Research on algae and their toxins in the required areas has been planned or initiated at 

several EPA research laboratories. Health effects projects being done at EPA’s National 

Health and Environmental Effects Research Laboratory (NHEERL) in Research Triangle 

Park, NC, includes a project with Wright State University to study biomarkers of 

exposure to microcystins. The same group also recently completed a project analyze 

microcystins in samples from Brazilian patients who received dialysis water containing 

microcystins. A different laboratory of NHEERL is looking at the effects of anatoxin-a 

89
on the behavioral responses of rats. This work may be expanded to the affect of 

anatoxin-a on mouse behavior, and future work may be done on behavioral responses of 

laboratory animals to saxitoxins. The EPA NHEERL laboratory in Gulf Breeze, FL, is 

conducting a project with the University of Miami to look at the affect of long term

exposure of fish to microcystin and cylindrospermopsin in two Florida lakes in which 

each of these cyanobacteria is a dominant species. 

EPA projects on the affect of water treatment on algal cells or toxins has been started or 

proposed in three areas. The EPA’s National Risk Management Research Laboratory 

(NRMRL) in Cincinnati is beginning a project on filtration of algal cells. This project 

will look at removal of cells during filter ripening, at the beginning of the filter cycle, and 

during breakthrough, at the end of the filter cycle. The filter will be a dual media sand 

and anthracite filter. Three species of cyanobacteria will be used, including Microcystis

which is unicellular, and Anaebena and Planktothrix, which are filamentous. The 

experimental variables will be the run time, and the loading rate. NRMRL in Cincinnati 

also has a treatment project with University of Wisconsin, the Wisconsin State 

Laboratory of Hygiene, and Lake Superior State University. This project will look at the 

affect of chlorine on microcystin LR and anatoxin-a. and the influence of pH on toxin 

fate during exposure to chlorine. The experiments may include the affect of chlorine on 

intracellular and extracellular toxins. An investigator of the Office of Ground Water and 

Drinking Water in Washington, DC, has proposed studying the fate of algal toxins during 

bank filtration. The primary means of reducing the toxins would be biodegradation of 

toxins by microorganisms in riverbank sediments. This project has yet not been funded. 

EPA has several analytical method development projects planned or under way, however, 

before method development can begin, analytical chemistry standards are needed. The 

EPA’s Office of Ground Water and Drinking Water (OGWDW) Technical Support 

Center (TSC) in Cincinnati is funding work at Wright State University to obtain 

cylindrospermopsin and anatoxin-a standards. The TSC has still not located a source of 

microcystin LA. The National Exposure Research Laboratory (NERL) in Cincinnati is 

doing a project to develop a single micro LC/MS method for several microcystin 

congeners, anatoxin-a and is planning to work on cylindrospermopsin if a standard can be 

gotten. Separation will be done with microbore HPLC and electrospray time of flight 

mass spectrometry will be used for detection and identification. OGWDW, TSC, in 

Cincinnati, is starting a project to develop an LC/MS method that will be standardized 

and validated so that it can be run by commercial labs that analyze samples for the EPA’s 

Unregulated Contaminant Monitoring survey for algal toxins. A concentration and cleanup step will be needed before analysis. The goal will be to make a single LC/MS 

method for 5 or 6 microcystins, anatoxin-a and cylindrospermopsin. OGWDW, TSC, in 

Cincinnati also is funding the initial steps toward development of immunoassay kits for 

cylindrospermopsin and anatoxin-a through Wright State University. Conjugates and 

haptens will be developed and given to a private company for development of the 

immunoassay kits. The National Center for Environmental Research (NCER) in 

Washington, DC, also offered a small business grant under their SBIR program for the 

development of these kits in 2002. NERL in Cincinnati is working with a company, 

Optec, to make an automated instrument for detection of algal toxins which uses 

90
aptamers. Aptamers are oligonucleotides that bind to specific molecules including algal 

toxins. They can be regenerated and reused. NERL in Cincinnati is planning to develop 

a taqman PCR method for identification of 6 different genera of toxic cyanobacteria. 

This method would give results in 2 to 3 hours and would be quantitative. OGWDW, 

TSC in Cincinnati is developing real-time PCR for a microcystin gene. This method will 

be used in a project to look at microcystin production under differing environmental 

conditions. OGWDW, TSC in Cincinnati is starting a project with Lake Superior State 

University. has been working on a standardized microscopic cell count method that could 

be used for all of the toxic genera of concern. This method will be used with the UCMR 

survey. 

EPA would like to conduct a risk assessment for algal toxins, if resources are available. 

The National Center for Environmental Assessment (NCEA) in Cincinnati would like to 

look at quantitative structure-activity relations for cylindrospermopsin and microcystins. 

NCEA is also interested in doing a risk assessment for the microcystins, 

cylindrospermopsin and anatoxin-a for the United States. 

EPA has done or is doing 3 small occurrence surveys for algal toxins in the last 2 years. 

NERL in Cincinnati has worked with USGS to survey 2 lakes and a river during the 

summer of 2001 for microcystin. The samples were archived and haven’t been analyzed 

yet. OGWDW, TSC in Cincinnati with Lake Superior State University did a survey in 

the summer of 2001 for microcystin. Cell counts were also done. The samples were 

archived and will be analyzed this summer. This summer OGWDW, TSC is conducting 

a survey with Lake Superior State University for cylindrospermopsin. Source water and 

treated water are being surveyed at 6 utilities. These were picked based on their past 

history of having cylindrospermopsin in the water. The samples from this survey are 

being archived until there is an analytical capability for cylindrospermopsin. 

EPA has a separate regulation to get occurrence information on CCL contaminants in

drinking water systems. This is the Unregulated Contaminant Monitoring Rule (UCMR). 

Algal toxins weren’t monitored under the first UCMR which goes from 1999 to 2004 

because there were no validated methods that could be used for the survey. It is likely 

that they will be monitored under the next UCMR monitoring list, or UCMR2, which is 

due to be promulgated in 2004. Since it takes at least a year to write regulations that are 

published in the Federal Register, to meet the 2004 deadline for publishing UCMR2, it 

will be necessary to have validated methods for the UCMR by the end of 2003 or early 

2004. Monitoring will probably be done for the toxins that have standards available. 

This includes 5 or 6 microcystins, cylindrospermopsin, and anatoxin-a. Based on the 

status of analytical methods, it is likely that there will be an LC/MS method and probably 

a microscopic cell count method in time for UCMR2 in 2004, but screening methods for 

the toxins, and genetic methods for toxin gene identification won’t be ready in time. 

Based on the cost of the analyses, the UMCR survey for algal toxins will probably be 

small, including 300 or fewer systems.

91
Therefore, these projects show that EPA is implementing research to get the information 

it needs to make a regulatory determination for algal toxins although it still doesn’t have 

all the needed information. 

The compilation of the second CCL will be very important for future studies of algal 

toxins, because algal toxins could be kept on the CCL or they could be dropped off of it 

which would affect EPA research and regulatory activities. The second CCL is due to be 

published in February 2003, and it will likely be very similar to CCL1. Future CCLs 

could be different, though. For future CCLs, EPA must consider an approach 

recommended by the National Research Council for picking CCL contaminants. The 

strategy that the NRC recommended was to start with a universe of about 80,000 

contaminants and pare the list down to a pre-CCL by using a neural network program in 

conjunction with expert judgment. The NRC also recommended screening potential 

microbial contaminants for the pre-CCL by characterizing them with quantitative 

structure activity relations for chemicals, or virulence factor activity relations or VFARs 

for microorganisms. The VFAR approach is to detect virulence factors that

microorganisms have. These virulence factors could be detected either by genotypic or 

phenotypic expressions. This approach could affect the selection of algal toxins for 

future CCLs since the selection criteria could be different than those used to pick CCL1 

contaminants. For CCL2, though, it is likely, though not assured, that algal toxins will 

remain on the CCL, and will continued to be considered for a regulatory determination.

Reference 

Scharfenaker, M.A. 2001. Making sense of the Unregulated Contaminant Monitoring 

Rule. JAWWA 93(6):24-42 

92
Summary of Florida Department of Environmental Protection’s 

Activities Related to Cyanobacterial Toxins 

Presented by: Richard Drew, M.S. Chief, Bureau of Water Facilities Regulation,

Division of Water Resource Management 

The Department of Environmental Protection [DEP] has several programs that either 

influence the presence or reoccurrence of cyanobacteria and their associated toxins or are 

impacted by the presence of the cyanobacteria. I will limit this discussion to two 

programs that influence the nutrient balance of Florida surface waters that in turn create a 

suitable environment for that group of organisms; and one program, drinking water, that 

is directly affected by its presence. 

The NPDES or National Pollutant Discharge Elimination program regulates the treatment 

and disposal of industrial and domestic wastewater. Specific effluent limits control the 

amounts of nutrients that can be discharged to surface waters, that in turn could promote 

eutrophication and the presence of cyanobacteria. The nutrient limits contained in 

facility permits are based on compliance with water quality standards, and the standards 

are related to the designated use or classification of the water body receiving the 

discharge. 

Direct wastewater facility discharges to shellfish areas [Class II] and to water bodies that 

serve as a source of drinking water [Class I] are prohibited in Florida. Even indirect 

discharges must demonstrate that what will be discharged will not affect the designated 

use of the downstream waters. While there are prohibitions for direct discharges to Class 

I and II waters, recreational waters [Class III] can receive discharges from wastewater 

facilities. However, these discharges, like indirect discharges to Class I and II waters, are 

only allowed if it is demonstrated by the facility permit applicant that they will not affect 

the designated use of the water body. In relation to cyanobacteria, the permit applicant 

must demonstrate that the nutrients added to the receiving water will not cause algaerelated pigments to exceed levels found in healthy waters. Therefore, the NPDES 

program has the ability to limit nutrient additions for any wastewater facility in the state. 

The remaining nutrient sources reaching surface waters and promoting algae blooms are 

derived from non-point sources, such as storm water runoff from construction areas, 

urban storm water, poorly operated residential wastewater treatment systems [septic tank 

systems], irrigation from agriculture/right of ways/golf courses, and atmospheric 

deposition. The TMDL or Total Maximum Daily Load program examines all water 

bodies in the state and for those determined to be impaired a process is set in motion. 

First the appropriate levels of pollutants are defined that will protect the designated use of 

the water body; then the sources of those pollutants are identified; and finally, an 

implementation plan is developed to reduce the loading to the appropriate level. It is in 

this program that the agency hopes to control all the nutrient sources supporting the 

occurrence of algae blooms. Here the concept of watershed management is applied to 

reduce nutrient loadings from all the sources in the basin. 

93
A DEP program that can be directly affected by the presence of cyanobacteria and their 

toxins is the drinking water program. Fortunately the potential for this to become a 

problem in Florida is greatly reduced by a vast system of aquifers that provide ground 

water to a majority of Florida’s population. Only 20 of about 6,400 public water systems 

(PWSs) use surface water. These 20 PWSs supply roughly 10% of Florida’s drinking 

water. Geographically, only one of the 20 systems is located in the northern part of the 

state. The rest are south of Orlando. Most are located within a 50-mile wide band 

running from West Palm Beach on the eastern coast to Charlotte Harbor and Ft Myers to 

the west. Most of these surface waters are slow moving and affected by water control 

structures. Fluctuating levels of organic color, iron, and acidity affect the quality [taste 

and odor] of the water and dictate the level of treatment used at these sites. 

Drinking water systems [WTPs] are required to meet a number of federal regulations that 

have been adopted by Florida. The regulations are even more complex for systems that 

draw their source water from surface waters. The treatment processes used at surface 

WTPs is based on the quality [including taste, clarity, and odor] of the water supply. As 

a result these systems are typically very responsive to changes in the source water 

character and take steps quickly to minimize citizen complaints. In regard to public 

notification, the Department requires annually the production and public distribution of 

Consumer Confidence Reports that summarize the quality of the water provided to the 

public. Recently, the EPA and in turn the DEP have adopted more stringent rules 

focused specifically on systems that use surface waters as their source water. Surface 

Water Treatment, Filter Backwash Recycling, and Stage 1 Disinfectants/Disinfection

Byproducts Rules are examples of these regulations. 

While there are no regulations that directly address the treatment of cyanobacteria and its 

toxins or establish specific water quality standards for these toxins, the water treatment 

plant must satisfy color and odor requirements of DEP and EPA. To this end, the facility 

must adopt a set of management strategies to handle the changing water quality of the 

surface water body serving as its source. Many of these management strategies have also 

been shown to be effective at removing or controlling cyanobacteria and its t toxins. 

Management strategies are site specific and can be categorized as controlling the impacts 

to the source water, pretreatment practices, and in-plant and post-plant treatment 

techniques. 

Watershed management was previously discussed and attacks the source of the problem – 

nutrients. However, depending on the size of the watershed feeding the source water, the 

implementation of watershed management techniques may be: impractical [technically or 

financially] in controlling nutrient loads to the basin; or, impractical in achieving long 

term results; or, may not be as effective as originally hoped even over the long term. 

This leaves the WTP with the entire responsibility of handling the algae bloom problem. 

Pretreatment practices include physical, chemical or biological treatment of the source 

water in situ, or prior to entering the facility’s treatment process train. Some in-lake 

94
management techniques, such as herbicide applications, are merely temporary fixes, 

attacking the problem of algae blooms as they happen. Use of a herbicide or algalcides 

[e.g., copper sulfate] can be most effective when used to maintain low numbers of algae, 

instead of application on a bloom when it can release toxins from the dead cells. It also 

appears to be less effective with continued use in the same water body. 

Other types of lake management practices either try to remove the nutrients from the 

water [chemical coagulants] or create an unsuitable environment for the development of a 

bloom, [aeration, pH adjustment]. Another technique is the use of off-line wetland 

treatment systems that filter [biologically or physically] nutrients out of the water and

into wetland vegetation and sediments. 

A drinking water treatment facility can also develop alternative sources of water to be 

used when blooms appear in their primary drinking water supply, i.e., above ground 

reservoirs, aquifer storage and recovery systems, backup wells, use of adjacent water 

utility water.

Treatment at the plant, particularly those facilities drawing surface waters, can involve 

several filtration treatment techniques that will effectively remove the algal cells, 

including in-bank filtration, coagulation and filtration, flocculation and filtration, and 

other forms of membrane filtration, such as reverse osmosis and nanofiltration. Some

WTP practices applied during blooms, such as the isolation of sludge and filter backwash 

water to waste can prevent the reintroduction of cells and toxins into the treatment 

process train. Disinfectants commonly used for pathogen removal, like chlorine and 

ozone can be partially effective at removal of the certain toxins. Powdered and Granular 

Activated Carbon [PAC & GAC] can be effective measures at removing some of the 

toxins, particularly PACs. Combining PAC or GAC with one of the disinfectants can 

improve the removal efficiency. Some oxidants, like potassium permanganate, have also 

been shown to be especially effective at removing the toxins. 

Surface waters in Florida commonly used as source waters are, unfortunately, often high 

in color and other organics, and have odors characteristic of stagnant wetlands. 

Fortunately, the techniques used to produce a good tasting, odor-free, clear drinking 

water, and compliant with DEP/EPA drinking water quality standards and new 

regulations, require employment of a series of treatment techniques that also seem to be 

very effective at removing cyanobacteria and theirs associated toxins. 

The evaluation of treatment techniques to effectively remove cyanobacteria and their 

toxins is in the early stages of discovery, as evidenced in recent publications [Chorus and 

Bartram[Ed.], 1999; Carmichael, 2001; Chorus[Ed.], 2001]. Ways to measure the 

presence of toxins, especially at the low concentrations observed in the environment are 

still being developed. Standardization of analytical methodologies and sampling 

protocols must be done to allow the WTP to have tools for detecting the toxins and have 

assurance that the values reported, for the increasing number of toxins, are accurate. 

95
Several systems in Florida are participating in current studies funded by the American 

Water Works Association Research Foundation and the St. Johns River Water 

Management District to examine the occurrence, quantity, and treatability of algal toxins 

at drinking water treatment systems. In addition, DEP is working with the surface water 

WTPs in a workgroup format to enhance the exchange of experiences each of the WTPs 

is having in dealing with this and other related problems. EPA is also evaluating 

cyanobacteria-derived group of toxins to determine if they will establish a maximum 

concentration level [MCL] for one or more of the more common cyanobacters. 

Where does this leave DEP, as regulators? On one hand, the information to date for 

Florida WTPs leads one to conclude only a small portion of the state’s drinking water 

systems are susceptible to potential introduction of cyanobacteria and its toxins. A high 

level of treatment is now being provided at these few systems caused by the nature of the 

water they now treat, and this treatment based on the research to date appears to be 

effective at controlling the introduction of toxins into the distribution systems. On the 

other hand, a fuller understanding of the problem and the effectiveness of treatment is 

still evolving. We should monitor this information and disseminate the results to the 

WTPs as soon as possible. We should also continue to work with the TMDL program to 

control the nutrient inputs to the watersheds containing the surface waters supplying these 

WTPs. Controlling and lowering the nutrients will reduce and hopefully eliminate the 

development of these algae blooms and the release of their toxins. 

References: 

Carmichael, W.W., 2001. ASSESSMENT OF BLUE-GREEN ALGAL TOXINS IN 

RAW AND FINISHED DRINKING WATER. AWWARF Public. No. 90815. 179pgs. 

Chorus, I., and J. Bartram, eds. 1999. Toxic Cyanobacteria in Water: A Guide to their 

Public Health Consequences, Monitoring and Management. London, UK: E&FN Spon. 

416pgs. 

Chorus, I., ed. 2001. Cyanotoxins: Occurrence, Causes, Consequences. Berlin: 

Springer. 357pgs. 

96
Aquatic Toxins Program 

Florida Department of Health 

Richard Clark, MS 

On August 13-14, 2003, the Florida Department of Health hosted a meeting in Sarasota, 

FL, entitled Health Effects of Exposure to Cyanobacteria Toxins: State of the Science. 

Many cyanobacteria researchers, water treatment plant personnel, and health care 

professionals gathered to exchange information and further Florida’s knowledge on this 

new area of science. The Florida Department of Health established their Aquatic Toxins 

Program in 1997 to track illnesses from persons exposed to algal toxins. The program 

created the Aquatic Toxin or Harmful Algal Bloom Hotline (888-232-8635) at that time

and began tracking illnesses and exposures to harmful algae. This program also 

participates in many research and educational activities. 

Aquatic Toxins Surveillance 

The surveillance activities of the program began in response to pfiesteria concerns in 

1997. Pfiesteria piscicida is an estuarine dinoflagellate that is believed to cause health 

problems in humans, but the results of years of research are conflicting and it has not 

been determine if pfiesteria actually produces a toxin. Florida does have pfiesteria in its 

estuarine water bodies, but we have had no confirmed illnesses related to exposure to this 

organism. 

The Aquatic Toxins Program also works closely with the Food and Waterborne Illness 

Program to track illnesses of people who have been exposed to an algal toxin through 

food sources. Florida has cases of Neurotoxic Shellfish Poisoning (NSP), ciguatera fish 

poisoning, puffer-fish poisoning and scombroid fish poisoning each year. Each of these 

illnesses is due to a toxin that is of algal or bacterial origin. 

Persons can also become ill from direct contact with the algal toxins. Skin rash, nasal 

and throat irritation, headache, and breathing problems can be associated with Red Tide 

(Karenia brevis) and cyanobacteria. The program receives hundreds of reports of 

illnesses from persons exposed to red tide each year. So far, there have been no 

confirmed reports of illness related to cyanobacteria in Florida. 

Research Activities 

The Aquatic Toxins Program is an active participant in many research projects in Florida. 

We collaborate on Red Tide studies with The National Center of Environmental Health, 

Centers of Disease Control and Prevention, University of Miami Medical School, 

Lovelace Respiratory Institute, Florida Department of Environmental Protection, 

University of North Carolina Wilmington, and Mote Marine Lab. The goal of these 

human health studies is to establish how red tide affects the environment and people. The 

studies involve environmental monitoring, air monitoring, and human health monitoring 

including: nasal and throat swabs, urine test, spirometry and questionnaires. 

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The Aquatic Toxins Program was also able to support the Department of Health’s 

Laboratory in Jacksonville, FL, in building capacity to test water for cyanobacteria and 

their toxins. The equipment is now in place and their first research project is underway. 

This project is testing how effective home filtration devices are at removing 

cyanobacteria and their toxins. 

The Aquatic Toxins Program will also be participating in a puffer-fish study with The 

Florida Marine Research Institute. Nineteen people had become ill after eating pufferfish caught in the Titusville, FL, area in 2002. The fish had bioaccumulated saxitoxin in 

their tissue, which had not been previously identified in the literature. Research will 

determine the toxicity of the 16 different species of puffer-fish and how they are 

distributed in Florida. This project will also determine from what species of algae was 

the toxin’s origin and what other organisms may contain the toxin. 

Education 

One of the main goals of the Aquatic Toxins Program is education and it has created 

materials for use by the county health departments, the public and the media. A 

“Cyanobacteria Update” is released to the county health departments when there is any 

new information of interest. The program is very active in providing assistance to the 

county health departments when they need to produce a press release related to pufferfish or red tide. 

Promotional items have been created for the public to get the hotline number out. 

Cyanobacteria magnets and key chains have been created along with red tide visors and 

key totes. Scientists and county health department staff distribute these items where 

people are recreating near water bodies. These items have the hotline number printed on 

them and they encourage people to call in if they feel they have been exposed to 

something in the water that has made them ill. 

The coordinator of the program has given many educational presentations at national and 

local scientific meetings, public meetings, county health departments and wildlife parks. 

Miscellaneous Aquatic Toxins Program Activities: 

• Letters written from FDOH to EPA regarding setting recreational and drinking 

water guidelines for cyanobacteria toxins. 

• Investigations into reported cases. 

• Creation of the physician workgroup 

• FDOH is an active member of the Florida Harmful Bloom Task Force 

• Cyanobacteria Literature Collection and review 

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• Red Tide Literature Collection and review 

• Participation in the production of professional posters and presentations to be 

given at scientific meetings 

• Coordination of conference calls 

• Response to media calls, emails, and questions from the public 

• Response to reports of swimmer’s itch, cercarial dermatitis, naegleria (amoeba 

that causes meningitis), jellyfish stings, fire coral, fish bites, etc. 

• Production of DOH education plans, business plans, media contact reports, etc. 

• Coordination of the State of the Science Cyanobacteria meeting: choosing 

speakers, setting the agenda, providing nametags, travel reimbursement, travel 

coordination, notebooks, and contracts with Mote and supporting agencies. 

Conclusion 

The Florida Department of Health’s mission is to promote and protect the health and 

safety of all people in Florida through the delivery of quality public health services and 

the promotion of health care standards. The Aquatic Toxins Program follows this 

mission throughout its activities in education, research and health surveillance. In 

Florida, harmful algal blooms like red tide and cyanobacteria are common, therefore, 

there is a potential for human illness. The program will continue surveillance for health 

effects of harmful algael blooms and to support Florida’s research regarding related 

emerging health concerns. 

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Summary of: Water Treatment 

Presented by: Bruce MacLeod, M.S. 

Mr. Bruce W. MacLeod, from the Manatee County Utility Operations Department, 

discussed the approach utilities take regarding cyanobacterial toxins. Mr. MacLeod 

began by discussing local newspaper articles related to cyanobacterial toxins. These 

articles, in Mr. MacLeod’s opinion, are likely to frighten the public. The Manatee 

County facility is a large one, which often uses unique treatment schemes to address sitespecific problems. General management strategies for the utilities include the prevention 

of blooms and the removal of toxins. Blooms can be prevented using lake aeration, 

algaecides, inactivation of phosphorous, lake shading, disruption and watershed 

management. Toxins can be removed from water by treatment with chlorine, ozone, 

potassium permanganate, UV and membranes. Each of these removal methods has its 

own problems, such as taste changes, time dependence and added costs. 

The Lake Manatee facility has a number of unique characteristics that impact treatment. 

It has a 125 square mile watershed and an instream reservoir dating back to 1967. The 

reservoir covers 1800 acres and has an average depth of 12.8 feet and a volume of 12 

billion gallons when full. The broad, shallow shoreline allows for algal growth on the 

periphery of the lake. The water is soft, acidic, highly colored and nitrogen-limited, with 

a total organic carbon (TOC) range from 10-30 mg/L. The temperature ranges from 15-

30 °C, with temperatures above 25 °C 65% of the time. Anabaena and Oscillatoria have 

been found recently. Also, a Microcystis bloom was observed several years ago. Blooms 

are more common in the winter, which is the dry season. 

Blooms have been prevented at Lake Manatee by spraying copper sulfate from an airboat, 

at temperatures between 21-30 °C. Problem areas are sprayed at filament counts of 2 

filaments/mL, and other areas are sprayed at levels above 2 filaments/mL. Mr. McLeod’s 

experiences have suggested that copper sulfate has had little if any impact on algal 

densities, with fragmentation of filaments being the only change. Anabaena circinalis 

was viable, even at copper levels of 1 mg/L. Copper may stimulate the growth of 

actinomycetes, and other organisms that produce taste and odor compounds. 

According to Mr. MacLeod, the watershed is being managed in a number of ways, which 

should reduce nutrient loading. First, efforts are made to encourage best management

practices (BMPs) for agricultural land uses. Homeowners on the watershed are educated 

about the use of xeriscaping and other low fertilizer methodologies. A watershed overlay 

district was established to limit housing density and prevent the use of reclaimed water. 

Manatee County has been purchasing watershed land since 1987, following a successful 

local ballot initiative. Thus far 43%, or 35,000 acres, of the watershed is publicly owned. 

A major focus at Lake Manatee is odorant removal. Prior to 1988, a qualitative method 

to determine the proper amount of active carbon was used. This method wasted money, 

due to chasing the effective carbon dose and still yielded complaints from water 

consumers. Between 1988 and 1989, an in-house quantitative method was developed, a 

treatment goal was set, optimization studies were performed and odorant levels were 

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monitored in raw and treated water. As a result of these efforts, the number of 

complaints decreased. 

Current activities include HPLC/MS method development for anatoxin, LPS and 

cylindrospermopsin, bench-scale membrane studies with microcystin-spiked filter 

effluent at the University of South Florida, expanded toxin monitoring and powdered 

activated carbon (PAC) treatment studies. Membrane filters have been found to reduce 

microcystin-LR in water samples by over 94%, as well as 60-96% of TOC, at the benchscale. Pilot-scale studies will be conducted at Lake Manatee by the end of 2002. 

Mr. MacLeod closed by discussing water industry needs related to cyanobacterial toxins. 

These include acute and chronic acceptable concentrations; dependable standards for 

anatoxin, cylindrospermopsin and endotoxins; rapid, easy and rugged testing methods 

and site-specific treatment studies. 

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