Managing Cyanotoxins

Home , Aplysiatoxin, Cyanotoxin, Microcystin

May 2019

Djanette Khiari, The Water Research Foundation Managing Cyanotoxins

CYANOBACTERIA ARE photosynthetic Health Advisories (HAs) for states and are taken up by the liver and bacteria that are common in all fresh- utilities to protect the public from cya- cause weakness and anorexia water and marine environments. They notoxins in drinking water. For children 2. Neurotoxins (usually anatoxin were historically called blue-green younger than school age, the HA was and saxitoxin), which affect the algae but their structure, genetics, set at 0.3 µg/L for total microcystin nervous system and physiology clearly identify them and 0.7 µg/L for cylindrospermopsin. 3. Dermatoxins (aplysiatoxin and as bacteria. Cyanobacteria in fresh- The corresponding values for adults lyngbyatoxin), which cause water systems are widely recognized are 1.6 µg/L and 3.0 µg/L, respectively. skin and mucous irritations as sources of toxins (cyanotoxins) and Although not enforceable, the pub- upon contact unpleasant tastes and odors in water lished HAs are intended to trigger utility supplies. Cyanobacteria are a normal actions including increased monitoring, Taste and Odor Compounds and Toxic component of the natural biota and tol- development of treatment strategies, Cyanobateria erate a wide range of climatic conditions and public notification of “do not drink/ THE MOST FREQUENTLY CITED cyano- and environments. A rise in the num- do not boil” advisories. EPA has also bacterial metabolites are geosmin and ber of cyanobacterial blooms, caused provided recommendations on how 2-methylisoborneol (MIB). Geosmin by eutrophication from decaying plant utilities can monitor and treat drinking and MIB impart unpleasant earthy/ materials and man-made pollution, water for cyanotoxins. Additionally, the musty odors to the water. Attempts is resulting in the production of more EPA Fourth Unregulated Contaminant to use taste and odor parameters as taste and odor compounds and natural Monitoring Rule (UCMR4), pub- potential indicators of the presence of toxins, which demands the attention of lished in December 2016, includes toxins have been inconclusive. Just as it water treatment authorities. Although 10 cyanotoxins/groups. is true that most cyanobacterial species cyanotoxins are less commonly found Due to the increase of cyanobacterial do not cause taste and odor problems, in drinking water than taste and odor blooms, the occurrence of several toxic it is also true that most do not produce compounds, their high toxicity is of metabolites (i.e., cyanotoxins) in water toxins. Some species that produce taste great concern. Due to global climate supplies has also increased. There is and odor compounds, however, can also change, toxin-producing cyanobacte- growing concern about the potential produce toxins. ria are spreading into more temperate for negative health effects in humans regions and becoming a more wide- and animals due to these toxins. These The Water Research Foundation spread problem. toxins enter water supplies through nat- (WRF) and Cyanotoxin Research Currently, there are no U.S. ural production and metabolic activities, WRF HAS SPONSORED RESEARCH ON Environmental Protection Agency (EPA) and through cell lysis and subsequent toxic algae since 1993, initially producing regulations for cyanotoxins. However, release of toxins. Water collection and a comprehensive resource guide for util- three cyanotoxins are included on the treatment activities may contribute to ities: Cyanobacterial (Blue-Green Algal) final contaminant candidate list (CCL3): the release of cyanotoxins. Toxins: A Resource Guide (project 925). anatoxin-a, microcystin-LR, and cylin- Presently, about 3,000 species of Since the publication of the guide, WRF drospermopsin. At present, the only cyanobacteria are known; however, has funded additional research on con- cyanobacterial toxin class that has been not all produce toxins. The organisms trol, treatment, and detection methods internationally assessed for health risk most frequently associated with toxin for cyanotoxins, much of it in collabora- is the microcystins. The World Health production are Microcystis, Oscillatoria, tion with research partners. Organization (WHO) has issued a pro- Cylindrospermopsis, Anabaena, The increased frequency of cyano- visional guideline value of 1 microgram Planktothrix, Aphanizomenon, Nodularia, bacterial blooms in the United States per liter (µg/L) for microcystin-LR in and Lyngbya. Most poisoning by the prompted WRF, in partnership with drinking water and many countries have cyanobacteria listed above involves the EPA, to fund one of the first proj- developed their own guidelines, depend- three types of toxins (specific toxic com- ects to investigate cyanotoxins as a ing on the types of cyanotoxins found in pounds are listed in parentheses): potential threat to U.S. water systems. their source waters. 1. Hepatotoxins (microcystin [usu- Published in 2001, the comprehensive The 2014 cyanotoxin event in Toledo, ally microcystin-LR and study, Assessment of Blue-Green Algal Ohio has sparked significant regulatory microcystin-LA], cylindrosper- Toxins in Raw and Finished Drinking Water activity. In June 2015, EPA issued 10-day mopsin, and nodularin), which (project 256), assessed microcystin

2 OF 8 © 2019 THE WATER RESEARCH FOUNDATION. ALL RIGHTS RESERVED. LAST UPDATED: May 2019 occurrence and treatment removal Water Professionals (project 4548b), is and Communication Strategies. This capabilities. During the project, 45 util- an action-oriented synthesis of relevant Focus Area has already funded three ities in the United States and Canada literature for utility personnel and the relevant projects: were surveyed for two years during water utility community, providing infor- ll “Refinement and Standardization cyanobacterial blooms. mation necessary to guide the develop- of Cyanotoxin Analytical Microcystin was found in 80% of the ment of a technically sound evaluation of Techniques for Drinking Water” source waters. Only two of the finished cyanotoxins as a water quality concern (project #4716) water samples were above the WHO for drinking water supplies and appro- ll “Developing Guidance for guidelines (1 µg/L). The study also priate mitigation measures. The guide Evaluation and Implementation showed that almost all utilities had ade- summarizes the most recent infor- for Control of HABs in Source quate procedures to reduce microcystin mation about cyanotoxin occurrence, Water” (project #4912) to safe levels in finished water. analytical methods and monitoring, ll “Utility Response to In 2014, WRF and the American and management strategies. Like the Cyanobacteria/Cyanotoxin Event; Water Works Association (AWWA) co- first guide, it is also intended to benefit Case Studies, and Lessons sponsored project 4548, Cyanotoxin water utility managers, operators, and Learned” (project 4914) Guides for Water Utility Managers, which consultants. More specifically, though, distilled and summarized information it is intended for users working for, or Treatment from the last 20–25 years of cyanotoxin with, water utilities that have already THERE ARE SEVERAL CONVENTIONAL research. This purpose of this project been determined to be at risk of having and advanced treatment options avail- was to develop two cyanotoxin utility cyanobacteria and possibly cyanotoxin able for the removal of cyanotoxins. action guides designed for use by water issues. While this second guide contains The key is in understanding the specific utility management and personnel, and more detailed information than the first toxin of concern, because different tox- the drinking water community. These guide, it is organized to help readers ins are removed/inactivated at varying guides were intended to synthesize navigate the issues and make informed degrees by different treatment technol- existing knowledge on cyanobacterial decisions about appropriate mitigation ogies. For example, several research and cyanotoxin events and provide prac- measures and how to be prepared in studies indicate that water treatment tical tools to help the water community case of toxic cyanobacteriablooms. plants that meet Stages 1 and 2 of the prepare for, and respond effectively to, In addition, an Emerging Disinfectants/Disinfection Byproduct potential events. Opportunities project, Cyanobacterial Rule by using ozone have a considerable The first manual, A Water Utility Blooms and Cyanotoxins: Research level of protection from several types of Manager’s Guide to Cyanotoxins (proj- Priorities for Drinking Water Protection cyanotoxins (such as microcystin), but ect 4548a), is a succinct summary of (project #4657), consolidated and not from saxitoxin. On the other hand, cyanotoxin occurrence trends, poten- synthesized the existing literature on pre-oxidants such as potassium per- tial health effects, preemptive and cyanotoxins into a summary document, manganate, ozone, and chlorine (which mitigation strategies, and potential which was reviewed during a facilitated are used to mitigate cyanobacteria) challenges. This guide is intended to expert symposium held in Boulder, CO, have been found to lyse cyanobacteria, help water utility managers recognize in June 2016. The presentations and a which releases toxins; therefore, it is if cyanotoxins may be an issue for their video from the workshop are available recommended that coagulation be used utility and what initial steps to consider. for viewing. Workshop participants prior to oxidation to remove whole cells. A short self-assessment allows utility included leading academics, govern- One of the first WRF projects to managers to assess the vulnerability mental scientists, water utility repre- address the removal of cyanotoxins of their water systems to cyanobacte- sentatives, and consultants. During the through water treatment was con- ria and cyanotoxin events and, when workshop, the participants identified ducted as a Tailored Collaboration needed, where they can find additional research gaps and needs related to project with United Water International information, available resources, and cyanotoxins in drinking water, which (Australia). The report, Removal of Algal necessary guidance. were translated into a multi-year Toxins from Drinking Water Using Ozone The second guide, Managing research agenda for WRF’s Focus and GAC (project 446), was published Cyanotoxins in Drinking Water: A Area, titled Cyanobacterial Blooms in 2002. The researchers conducted lab Technical Guidance Manual for Drinking and Cyanotoxins: Monitoring, Control, and pilot plant tests for the control of

cyanotoxins through treatment (ozone, 30 minutes. Biological degradation pro- operating costs, and effort required to granular activated carbon [GAC], bio- vided 35% removal of microcystin-LR; ensure process control. logical filtration) to assess the optimal thus, it was recommended that it should The effect of common preoxidants conditions under which microcystin, be used as a polishing step in conjunc- used during water treatment on the anatoxin-a, and saxitoxin are inacti- tion with other treatment methods, integrity of cyanobacteria cells, and vated. It was found that ozone is an such as UV, oxidation, ozonation, PAC, the subsequent release of toxic metab- efficient treatment for anatoxin-a and and GAC. The RO and NF membranes olites, odorous metabolites, and dis- microcystin. However, saxitoxin is not tested removed microcystin-LR effi- infection byproduct (DBP) precursors, readily destroyed under the same con- ciently, at a minimum of 95%. Based on was investigated in WRF project 4406, ditions. The study also determined that the effectiveness of the technologies Release of Intracellular Metabolites GAC adsorption is not effective for the above, costs of implementation and from Cyanobacteria During Oxidation removal of microcystins. However, a engineering considerations are pro- Processes. The digital flow cytome- later study demonstrated that GAC is vided in the report for utilities to make ter provided a rapid method to obtain effective if it is replaced frequently. In suitable treatment decisions. quantitative and qualitative information addition, excellent removal is achieved Project 4016, Evaluation of Integrated regarding cyanobacteria cell damage when GAC is operated in the biological Membranes for Taste and Odor and Algal and lysis compared to conventional mode. Effective removal of toxicity was Toxin Control, was a partnership with light microscopy. Results showed that found with GAC for saxitoxin. Biological the Australian Cooperative Research cyanobacteria cell damage occurred filtration was not effective for saxitoxin. Center for Water Quality and Treatment without complete lysis or fragmenta- Building on this project as well as (CRCWQT). This project studied the tion of the cell membrane under the other research, a Tailored Collaboration feasibility of membrane technologies conditions tested. Results from this project with the City of Cocoa (Fla.), (ultrafiltration [UF], NF, and RO) in study showed that low oxidant expo- Treatability of Algal Toxins Using Oxidation, conjunction with coagulation, PAC, or sures could result in the release of Adsorption, and Membrane Technologies microfiltration (MF) membranes for the cyanobacteria metabolites. Depending (project 2839), was funded to identify removal of taste and odor compounds on the cell concentration, oxidant expo- and assess viable control and treat- and cyanotoxins. The study focused on sure, and the magnitude of DOC release, ment methods, including design, oper- the removal of extracellular MIB, geos- sufficient intracellular organic material ating criteria, and estimated treatment min, cylindrospermopsin, and the major concentrations may be released result- costs, to mitigate microcystin-LR in microcystin variants by RO and NF. The ing in impacts on regulatory compli- finished water. The study conducted project evaluated a UF integrated mem- ance (THMs and HAAs) or consumer bench-scale tests for the following brane system (IMS) ideally suited to the confidence (MIB and geosmin). With

treatment technologies: UV/H2O2, removal of dissolved algal metabolites respect to microcystin-LR, utilities ozone/AOP, powdered activated carbon (microcystins, geosmin, MIB, and cylin- using chloramines ahead of any phys- (PAC), GAC, biological degradation, and drospermopsin). The removal of cyano- ical treatment barrier are at the great- membranes (reverse osmosis [RO] and bacteria during integrated membrane est risk for releasing and accumulating nanofiltration [NF]). treatment and the subsequent potential microcystin-LR within the treatment

UV/H2O2 was effective but was dic- release of algal metabolites (i.e., toxins) process. Ozonation has shown the ability

tated by H2O2 concentrations and avail- were also evaluated. The study shows to release metabolites. However, ozone ability; UV alone was not effective. The that a tight NF membrane as a final reacts rapidly with microcystin-LR and study found GAC was effective at remov- stage of an IMS may be the best method hydroxyl radicals, which can minimize ing microcystin when GAC was replaced for maximizing removal of extracellular the effect of the metabolite release via frequently and total organic carbon con- cyanobacterial metabolites. An NF-IMS cell damage. Overall, physical removal centrations were low. The ozone/AOP would be most suited to an area where of cells is recommended before the combination was effective at removal, cyanobacterial metabolites continu- primary disinfection step in a water mostly if pH was below 7; doses as low ously occur. Lastly, the project devel- treatment process to avoid the release as 0.4 mg/L achieved microcystin-LR oped several options for water utilities of these metabolites. removal greater than 97%. PAC was also seeking an IMS for control of cyanobac- As most drinking water utilities able to remove microcystin-LR at doses teria and metabolites. These options still rely on conventional treatment, of 10 mg/L and with a contact time of span a range of complexity, capital and the objective of WRF project 4315,

Optimizing Conventional Treatment for activated carbon, may lead reduction within the sludge treatment the Removal of Cyanobacteria and Toxins, to improvements. facility. This is particularly important in was to develop guidance for water utili- ll Although removal of cyanobacte- the presence of saxitoxins, which are ties on the optimization of conventional ria through conventional coagu- recalcitrant to biological degradation. treatment for the removal of cyanobac- lation can be very effective, teria and metabolites while meeting 100% cell removal is unlikely in Detection Methods all other water quality goals. Based on normal full-scale operations. In IN RESPONSE TO THE INCREASING the results of the study, a set of rec- the event of high cell numbers frequency of cyanobacterial blooms, ommendations for optimized opera- entering the plant monitor for greater awareness of toxic cyanobac- tions during cyanobacteria challenges cell carryover and accumulation teria, and new methods of detecting were developed: in clarifiers, this can lead to seri- and monitoring cyanotoxins, robust ll Do not use pre-chlorination for ous water quality problems if analytical methods must be available improved coagulation or reduced not rectified. to monitor for toxins and assess their coagulant dosing during a cyano- Once captured in the sludge, cyano- significance. These methods either bacterial bloom unless compre- bacteria can remain viable and multi- detect specific toxins or measure over- hensive testing has identified a ply over a period of at least 2–3 weeks. all toxicity. There are several detection dose high enough to destroy Simultaneously, within one day some methods for cyanotoxins: high perfor- released toxins. Do not apply cells in the sludge will lyse and release mance liquid chromatography (HPLC), pre-chlorination when cyanobac- NOM and metabolites. Based on proj- gas chromatography coupled with mass teria producing MIB or geosmin ect 4315 findings, and to better under- spectrometry (GC/MS), liquid chroma- are present. stand the behavior of cyanobacteria, tography coupled with mass spectrom- ll Potassium permanganate dosing the dominant processes occurring in etry or tandem mass spectrometry may be applied for the control of the sludge and supernatant, and the (LC/MS and LC/MS/MS), and enzyme- manganese and iron in the pres- subsequent release of cyanobacterial linked immunosorbent assay (ELISA). ence of A. circinalis and metabolites, a follow-up project was ini- The toxicity assays include the neuro- M. aeruginosa. tiated. The primary goal of Management blastoma assay and the phosphatase ll Practice pH control to pH > 6 if of Treatment Sludge Impacted by inhibition (PIP) assays. The ELISA and this is not part of normal opera- Cyanobacteria (project #4523) was to PIP are currently commercially avail- tions. This will reduce the risk of provide operational guidance for the able. Depending on the cyanotoxin, one cell lysis and metabolite release management of cyanobacterial sludge method may be preferable over another. during treatment. to ensure compliance with the regula- More recently, molecular methods have ll Optimize NOM removal using the tions for cyanotoxins and to safeguard been developed to identify the genes criteria ΔC/C0 DOC, UV, and color water quality. The main recommen- controlling toxin production. –< 0.05 and the cell removal should dation from this research was that a Published in 2012, project 4212, be optimized as well. risk assessment and verification of Rapid Concentration and Detection of ll While turbidity cannot be used as existing treatment barriers be carried Microcystin and Other Cyanobacterial an indicator of the presence of out assuming the “worst case scenario” By-Products in Drinking Water, evaluated cyanobacteria or cell concentra- of all cyanobacteria entering the plant, the use of surface enhanced Raman tion, use the decrease in settled lysing, and resulting in dissolved metab- spectroscopy to concentrate and quan- water turbidity with coagulant olites returning to the head of the plant— tify cyanobacterial byproducts. The goal dose as a surrogate for, or indi- possibly at a concentration 2–5 times of the research was to develop a sim- cator of, cell removal if the initial higher than expected from a mass bal- ple and economically feasible detection turbidity is ≈10 NTU or above. ance of the inlet concentrations. If the scheme for microcystin-LR and MIB ll If the presence of cyanobacteria treatment barriers are insufficient to that could be implemented in a water results in increased coagulant mitigate a potential challenge, sludge treatment facility. The study showed demand to achieve improved set- supernatant should be disposed of in that drop coating decomposition Raman tled water turbidity the applica- an alternative manner for the duration spectroscopy (DCDR) can be a power- tion of a particulate settling aid, of the bloom, unless regular monitor- ful tool for qualitative and quantitative or even powdered ing of metabolites indicates significant analysis of cyanobacterial byproducts.

The data suggests that DCDR can suc- the past few years. As most methods to method to identify toxic cyanobacteria. cessfully identify microcystin-LR within detect toxins only work after the bloom A comprehensive literature review and a DOM matrix, produce reproducible has occurred, molecular tools, which industry questionnaire were used to spectra for samples up to 6 months old, can determine the potential of a popu- identify and select a suitable platform quantity microcystin-LR in samples of lation to produce toxins, may provide the technology for rapid genetic identifica- 2–100 ng, and distinguish between sim- best forecasting tool available for source tion of toxic cyanobacteria. The project, ilarly structured microcystin variants. water control strategies. Molecular co-sponsored with the CRCWQT, iden- A report published in 2007, technology enables spatial and tem- tified the genes likely to be involved in Determination and Significance of poral information on the distribution of cylindrospermopsin production in C. Emerging Algal Toxins (project 2789), toxic algae to be gathered rapidly with raciborskii, and attempts were made to co-sponsored with the CRCWQT, evalu- replication. These key advantages are identify and sequence genes likely to be ated and developed methods available not available when using microscopic involved in the production of anatoxin-a. for detection of cyanotoxins. The study analysis and provide an important aug- The project also developed a simple and further developed methods for the mentation to routine microscopy and rapid method for the preparation of detection of saxitoxin, anatoxin-a, and toxin analysis when more detailed and cyanobacteria-containing water sam- cylindrospermopsin. This included their rapid information about key toxic spe- ples. Finally, a method was developed detection by a single method; an LC/ cies is required. and tested successfully in the laboratory MS/MS method for detecting saxitoxin, A 2007 report, Development of and the field to adapt conventional PCR anatoxin-a, and cylindrospermopsin in Molecular Reporters for Monitoring assays for cylindrospermopsin-produc- a single analytical run was successfully Microcystis Activity and Toxicity (proj- ing cyanobacteria to real-time PCR. developed. (For low concentrations, ect 2818), identified regions of the Project 4020, Methods for Measuring pre-concentration using carbon-based Microcystis aeruginosa genome that Toxins in Finished Water, investigated a solid phase extraction cartridges was could be used as molecular targets in range of biological methods as tools required.) The neuroblastoma assay the rapid identification of potentially for source water and finished water detected saxitoxin that was not detected toxic cyanobacterial blooms containing toxicity measurements that may be by other methods. ELISA methods, these cyanobacteria. This project devel- suitable for detecting toxins in finished including commercially available test oped a presence/absence approach waters. Biological assays have not kits, were also evaluated for detect- (multiplex-polymerase chain reac- been refined for application to drinking ing microcystin, with good results. tion [PCR]), as well as a quantitative water. One of the key objectives of the PCR-based methods for the detection approach (using qPCR), which could project, co-sponsored with the Drinking of toxic cyanobacteria were applied to be easily applied in field situations. Water Inspectorate (U.K.) and CRCWQT, a number of field samples, but it was To demonstrate that these molecular is to define methods for quenching found that determination of cyanobac- tools worked under field conditions, the chlorine in finished water, as this is terial toxicity using PCR-based assays researchers tested the probes during known to interfere with current toxicity needed further validation using a wider blooms of potentially toxic cyanobacte- screening methods (i.e., MicroTox® and range of samples. Overall, the project ria Microcystis spp., which persisted in CheckLight). Chemical quenchers were suggests HPLC methods (and to a lesser western Lake Erie in the United States determined to be more suitable for use extent, ELISA), can detect and quantitate during August 2002–2004, when micro- with bioassays than any of the physical toxins present at low µg/L levels. Finally, cystin concentrations exceeded the methods of dechlorination evaluated. an occurrence study detected micro- safety limit set by WHO. The presence The appropriateness of the quencher, cystin in both U.S. and Australian raw of Microcystis spp. in water samples either sodium thiosulfate, sodium water samples. Cylindrospermopsin was confirmed through the multiplex sulfite, ascorbic acid, or taurine, was was detected in Australian but not U.S. PCR reaction using a combination determined by the assay. Surprisingly, samples. Saxitoxin and anatoxin-a were of four primer sets. Quantification of a number of the bioassays tested were not detected in any raw water samples Microcystis was achieved using the real- not adversely affected by chlorine, in either country. time PCR assay. meaning that finished water samples Several WRF projects researching Early Detection of Cyanobacterial can be tested in these formats without the genetic basis for toxin production Toxins Using Genetic Methods (proj- any quencher treatment. These assays by cyanobacteria have been funded in ect 2881), developed a rapid genetic included reticulocyte lysate assay for

6 OF 8 © 2019 THE WATER RESEARCH FOUNDATION. ALL RIGHTS RESERVED. LAST UPDATED: May 2019 protein synthesis inhibitors, and the detection of low levels of cyanotoxins in cannot rely on biodegradation to control cell culture based assays utilizing either drinking water. In addition, this report microcystin, and cylindrospermopsin in toxicity or genotoxicity endpoints. In provides valuable information for the drinking water reservoirs because tox- addition to the effects of chlorine and design of future in-ter-laboratory ins can be present in the water column the quenchers, the natural waters studies to compare and evaluate these without toxin-degrading bacteria being tested affected some assays. Thus, val- methodologies and provide guidelines present. Cylindrospermopsin can per- idation of bioassays using the waters for water quality monitoring. sist for months in the water column, they are intended to be used with should suggesting that biodegradation does be included during assay establishment. Source Water Control not always occur. Additionally, screen- Because none of the aforemen- CYANOBACTERIAL BLOOMS OCCUR ing with PCR for microcystin-degrading tioned detection methods are stan- seasonally and are generally a result organisms revealed that these organ- dardized, WRF funded a research project of over-enrichment by plant nutrients, isms were not always present in toxic with the EPA, Criteria for Quality Control particularly nitrogen and phosphorous. blooms of Microcystis aeruginosa. Protocols for Various Algal Toxin Methods Human influences such as urbanization, (project 2942), to develop quality assur- increasing population, and agriculture Water Utility Guidance ance protocols for the quantitative contribute to the incidence of cyano- IN THE EARLY 1990S, SEVERAL different analysis of microcystin, saxitoxin, cylin- bacterial blooms. As stated previously, countries, including Canada, Australia, drospermopsin, and anatoxin-a present not all cyanobacterial blooms cause and the United Kingdom, developed in water and of cyanobacterial extracts. the production of toxins. Cyanobacterial health guidance levels for microcystin The project report, which was published blooms may consist of strains not in drinking water. In order to manage in 2010, recommended extraction meth- actively producing toxic metabolites, or the potential hazard of cyanobacterial ods, concentration methods, production producing several simultaneously; con- toxins, water suppliers needed knowl- of analytical standards, and preserva- sequently, the toxicity of a bloom is diffi- edge not only of health risks, but also of tion of water samples containing toxins cult to establish. In addition, the use of the nature and causes of cyanobacterial of the various cyanotoxins. copper sulfate in reservoirs to treat cya- blooms, the methods of monitoring and The objectives of project 4647, nobacterial blooms causes the cells to controlling toxins, the effectiveness of Evaluation and Optimization of Microcystin lyse and potentially release toxins. This water treatment practices in removing Analytical Methods, were to investi- uncertainty necessitates active source toxins, and strategies for preventing and gate and determine the capabilities of water control and monitoring of water mitigating toxic bloom development. commonly used methods to quantify quality for cyanobacterial toxins. Published in 1995, Cyanobacterial microcystin (MC) concentrations at Reservoir Management Strategies (Blue-Green Algal) Toxins: A Resource part-per-million or lower concentra- for the Control and Degradation of Algal Guide (project 925) provides utilities with tions. Several published methods were Toxins (project 2976), co-sponsored a comprehensive guide to addressing examined. Information from various lab- by CRCWQT, investigated cyanotoxin cyanotoxin concerns, including strate- oratories was obtained through surveys degradation in reservoirs by toxin- gies for communicating with the public and information requests to determine degrading organisms and developed on potential risks of these toxins. The the extent of how each of the methods reservoir management approaches for guide outlines several tiered approaches is utilized. Addi-tionally, samples were the control of toxin production using to managing, monitoring, and analyzing collected from various utilities and ana- an ecological model. Reservoir hydro- toxins. As an example, the monitoring lyzed using these methods. The resul- dynamics and growth of algal species plan, originally developed in Australia, tant data from the samples analyzed were successfully simulated with the introduces graduated response and was compiled and compared. The accu- computer model. The timing and mag- action levels to increasing levels of racy and precision of each method were nitude of blooms were similar for the toxic cyanobacteria in source waters. In established and method limitations field and the simulated data sets. The Australia, the Alert Levels Framework such as interferences, MC degradation model was extended to include toxin developed in the 1990s as a monitor- by-products, and the cross-reactivity production and degradation, which ing and management action sequence were identified. The information gen- when applied to any reservoir would provides a graduated response to the erated from this project can be used predict the risk of cyanobacterial toxins. onset and progress of a cyanobacterial to inform and educate utilities in the The study also determined that utilities bloom. For instance, in the framework,

© 2019 THE WATER RESEARCH FOUNDATION. ALL RIGHTS RESERVED. 7 OF 8 Alert Level 1 (cyanobacterial biomass used to develop recommended health ll Evaluation of Integrated Membranes 2,000 cells/mL, 0.2 mm3/L biovolume, advisory/alert language. A webcast with for Taste and Odor and Algal Toxin or 1 mg/L chlorophyll a) is the first step preliminary project findings was held in Control (2012, project 4016) at which management action is taken. June 2017, and is available for on-de- ll Rapid Concentration and Detection of Over the past 20 years, a number of mand viewing. Microcystin and Other Cyanobacterial organizations in several different coun- By-Products in Drinking Water (2012, tries have conducted research on man- WRF Research Cited in this Article project 4212) aging cyanobacteria and the toxins they ll Refinement and Standardization of ll Criteria for Quality Control Protocols produce. The research was published Cyanotoxin Analytical Techniques for for Various Algal Toxin Methods (2012, in various papers, reports, and books, Drinking Water (ongoing, project 2942) but consolidation of the knowledge was project 4716) ll Methods for Measuring Toxins in needed. The Global Water Research ll Developing Guidance for Evaluation Finished Water (2010, project 4020) Coalition (GWRC), of which WRF is a and Implementation for Control of ll International Guidance Manual for founding member, addressed the need HABs in Source Water (ongoing, the Management of Toxic for a single, comprehensive resource project 4912) Cyanobacteria (2010, project 3148). for water suppliers worldwide with the ll Utility Response to Cyanobacteria/ ll Treatability of Algal Toxins Using project, International Guidance Manual for Cyanotoxin Event; Case Studies, and Oxidation, Adsorption, and Membrane the Management of Toxic Cyanobacteria Lessons Learned (ongoing, Technologies (2010, project 2839) (project 3148). The manual includes project 4914) ll Reservoir Management Strategies for perspectives from several countries on ll Evaluation and Optimization of the Control and Degradation of Algal health effects, reservoir management, Cyanotoxin Analytical Methods (2019, Toxins (2008, project 2976) analytical methods, and treatment tech- proejct 4647) ll Determination and Significance of nologies to mitigate several species of ll Cyanobacterial Blooms and Emerging Algal Toxins (2007, cyanotoxins. Cyanotoxins: Research Priorities for project 2789) Four Steps to Effective Cyanotoxin Drinking Water Protection (2018, ll Development of Molecular Reporters Communications: A Risk Communication project 4657) for Monitoring Microcystis Activity Toolkit (project #4697) provides tem- ll Four Steps to Effective Cyanotoxin and Toxicity (2007, project 2818) plates and tools for utilities, regulatory Communications: A Risk ll Early Detection of Cyanobacterial agencies, and water professionals to Communications Toolkit (2018, Toxins Using Genetic Methods (2007, better communicate about the risks project 4697) project 2881) associated with cyanotoxins in drink- ll Management of Treatment Sludge ll Removal of Algal Toxins from Drinking ing water supplies. This report was Impacted by Cyanobacteria (2016, Water Using Ozone and GAC (2002, published in January 2018. The report project 4523) project 446) describes specific attributes of a cyano- ll A Water Utility Manager’s Guide to ll Assessment of Blue-Green Algal toxin risk management framework that Cyanotoxins (2015, project 4548) Toxins in Raw and Finished Drinking can create potential communication ll Optimizing Conventional Treatment Water (2001, project 256) barriers, for example the complexity of for the Removal of Cyanobacteria and ll Cyanobacterial (Blue-Green Algal) the EPA health guidance and the uncer- Toxins (2015, project 4315) Toxins: A Resource Guide (1995, tainty inherent in monitoring and test- ll Release of Intracellular Metabolites project 925) ing timing and protocol. The report also from Cyanobacteria During Oxidation includes linguistic research, which was Processes (2013, project 4406)

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