Monitoring of cyanobacteria and their toxins in Finnish recreational waters and at operating waterworks

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1 Monitoring of cyanobacteria and their toxins in Finnish recreational waters and at operating waterworks Jarkko Rapala National Product Control Agency for Welfare and Health, P.O.Box 210, FIN Helsinki, Finland Monitoring of phytoplankton in lakes since 1933 Microscopical monitoring of cyanobacteria in lakes has long traditions in Finland. The Finnish Environment Institute (SYKE) database contains results of approximately quantitative phytoplankton samples since Since 1960's, the studies have been focused on nuisance phytoplankton, especially cyanobacteria. Due to the unexceptionally extensive and long-lasting cyanobacterial blooming in the summer 1997 it was decided that there is a need for more systematic real-time information about the cyanobacterial situation in the country and information on their spatial and temporal variation during the summer months. Systematic monitoring of cyanobacteria in lakes since 1998 In summer 1998 a nation-wide observation system was launched to monitor cyanobacteria. Observation sites (>300) represent various water types: eutrophic waters with frequent cyanobacterial mass occurrences, mesotrophic waters with less frequent water blooms and oligotrophic waters with no or few observations of nuisance algae or cyanobacteria. Several of the sites are situated in the vicinity of cities or public beaches. The cyanobacterial abundance is monitored weekly in June August from the predetermined sites. Municipal authorities or volunteer citizens visit the sites by Monday Tuesday, and estimate the cyanobacterial abundance by visually examining the water area from the shore. The observations are classified into four classes (0-3): 0: No algae. No algae on the water surface or on the shore line. 1: Observed. Greenish flakes detected in the water or when taken into a transparent container, or narrow stripes on the shore. 2: Abundant. The water is clearly coloured by algae, small surface scums or cyanobacterial mass on the beach are detected. 3: Very abundant. Wide and heavy surface scums or thick aggregates of cyanobacteria are detected on the shore. The data is collected by the regional environment centres (n=13) and sent to SYKE by Wednesday, where the weekly report is prepared on Wednesday a.m. The report consists of four different parts: 1. The short one-page summary of the weekly situation. 2. The map which shows by colour codes the situation at each observation site. 3. The cyanobacterial "abundance barometer" (balanced mean of the observation sites and cyanobacterial abundance) which allows comparison of the current situation to previous years. 4. Descriptions of regional situations.

2 The report is published each Wednesday at noon or early in the afternoon at the Internet pages of SYKE ( and by giving a press release. Data on the Baltic Sea areas is also published at the Internet pages of Finnish Institute of Marine Research ( If cyanobacteria are estimated as abundant or very abundant a water sample is taken and sent to SYKE or regional environmet centres for further microscopical investigation, and the species composition is recorded in the national database. In addition, in the open Baltic Sea areas cyanobacteria are monitored by using unattended recording, sampling on passenger ferries, and by coastguard from the air. Also satellite images are used in estimating the size of the surface blooms. Selected lakes, those of special interest, have been routinely monitored for the presenceof cyanobacteria during summer months by microscopically identifying cyanobacteria and counting their biomass. If the resources have allowed, toxins (mainly microcystins) have been included in the analyses. In most cases, the results show that cyanobacterial biomass and toxin concentrations correlate well. This implies that visual or microscopical examination of water is able to give a sufficiently reliable estimate of the hazard posed by cyanobacteria. Implementation of the Bathing Water Directive (2006/7/EC) Cyanobacteria have been monitored at the public beaches in Finland since 1980's. If cyanobacteria are detected, the health inspectors have been advised to immediately place warning signs by the shore. Thus, the demand of the new Bathing Water Directive to monitor for cyanobacterial proliferation at public beaches will not cause significant changes on the practices. On the basis of research and the long experience in monitoring of cyanobacteria, a national monitoring scheme has been proposed (see figure below). The classification system described above (abundance 0 3) and the monitoring scheme described below will be applied in the national implementation of the Bathing Water directive. The scheme presented is suitable for risk management purposes as well in recreational waters as in raw waters of drinking water treatment plants.

3 Telephone services During summer months (June August) since 1998 there has been at SYKE a continuous (Monday Friday, ) telephone service ("Citizens Algaline") from which the public can get information about cyanobacteria. On average, 350 telephone calls have been received each summer. In the dry and hot summer 2002 altogether over 670 calls were recorded. A similar telephone service ("Algaline"), mainly for the coastal areas, is also provided by Finnish Institute of Marine Research. The Poison Information Centre at Helsinki University Hospital provides a 24-hour telephone service which gives medical advice for persons in acute poisonings of any kind. During summer months, approximately 100 telephone calls are received concerning adverse health effects suspected to be caused by cyanobacteria. In 1997 (the year of heavy cyanobacterial blooms) there were more than 350 contacts concerning cyanobacteria. Monitoring of cyanobacterial toxins More systematic monitoring of microcystins was started in Finland in the early 1990's. Since then, methods have been taken into use to detect also anatoxin-a, PSP-toxins and anatoxina(s). However, the monitoring of toxins has been totally dependent on research funding. As research funding has decreased, routine monitoring of the neurotoxins is currently not feasible. Drinking water treatment plants During years aresearch on the removal of cyanobacteria and microcystins was conducted at 12 operating drinking water treatment plants that use surface water for their raw water, and different water purification methods. Prior to this, a similar study was conducted at five bank filtration waterworks. The results of the studies indicated that toxic cyanobacteria occur frequently in the raw waters of the waterworks. Bank filtration removed efficiently the cyanobacterial cells and microcystins. At the surface water plants the majority of cyanobacterial cells, and thus the majority of the microcystins, were removed during the coagulation clarification process. Coagulation clarification stage is thus the prerequisite water treatment stage for effective removal of microcystins. However, residual microcystins were often detected after this stage, and only activated carbon filtration or ozonation were able to remove the microcystins under the level of detection. Intensive monitoring on the removal of cyanobacteria, microcystins, phytoplankton, heterotrophic bacteria and endotoxins was conducted at one surface water treatment plant with coagulation, clarification, sand filtration, ozonation, slow sand filtration and chlorination as the treatment process. Coagulation sand filtration reduced microcystins by , and endotoxins by log 10 units. Ozonation effectively removed the residual microcystins. The treatment process reduced phytoplankton biomass by , and heterotrophic bacteria by log 10 units. In treated water, the concentration of microcystins never exceeded the WHO guide value (1.0 µg l -1 ), but picoplankton and monad cells were often detected in high numbers.

4 The Finnish Health Protection Act states that drinking water must not contain any substances in such numbers or concentrations which may constitute a health hazard to human health. On the basis of the reseach results, the authorities have advised to monitor cyanobacteria visually and microscopically from the raw waters, especially from the incoming water to the waterworks, and the treated drinking water. Due to the high number of toxic compounds produced by cyanobacteria, analysis of specific toxins from drinking water has not been considered feasible. However, if the cyanobacterial water bloom is persistent in the raw water source, or if cyanobacterial cells are detected in the treated water, microcystin analysis using detection methods which are as rapid as possible, such as ELISA or protein phosphatase inhibition assay, are advised. Depending on the cyanobacterial species composition, analysis of also other toxins may also be considered. Adverse human health effects associated with cyanobacteria in recreational waters During years the telephone calls to the Poison Information Centre and the data on occurrence of cyanobacteria obtained through the nationwide observation network (see above) were connected to acute human intoxication symptoms reported by water users exposed to cyanobacteria. Over six hundred cyanobacterial water blooms were studied for species composition and the presence of toxins. Approximately 130 samples were associated with adverse human health effects (headache, skin and eye irritations, fever, vomiting, diarrhea, and more severe symptoms such as visual disturbances, seizure and musculoskeletal symptoms). Over 150 patients were interviewed, and their symptoms were linked to the results of the water analyses. It was shown that the exposure route to cyanobacteria explained the human symptoms better than any specific toxic compound measured from the samples (cyanobacterial hepatotoxins and neurotoxins, lipopolysaccharide endotoxins). Exposure through inhalation and skin was shown to cause more symptoms and relatively higher percentage of the more severe symptoms than exposure through e.g. ingestion. Also several potential human and animal bacterial pathogens were detected and isolated from the water samples containing cyanobacteria. From the recreational water samples the highly neurotoxic saxitoxin was found for the first time in Finland, and in high concentrations (up to 10 mg/l). The occurrence of the toxin correlated strongly with the presence of the cyanobacterium Anabaena lemmerannii and with high N/P ratio of the lakes. Also microcystin concentrations were occasionally very high (up to 44 mg/l). Neurotoxins of cyanobacteria were associated with oligo-humic lakes, and hepatotoxins with moderately humic lakes. The emerging cytotoxin cylindrospermopsin was detected for the first time from a cyanobacterial strain, Anabaena lapponica, isolated from boreal aquatic environment. Conclusions According to research results, the majority of cyanobacterial occurrences are toxic. Thus, the presence of cyanobacteria alone is a strong indication of potential health hazard. The immediate warning of water users of the risk caused by cyanobacteria should be the main target. This target can be achieved only by rapid and thus relatively simple means, such as visual observation of the bathing water.

5 Analysis of specific toxins is too time consuming in order to meet the need of rapid assessment and action. If e.g. microcystins were analysed from the water samples, there may still be other hazardous compounds present in the water, because cyanobacteria produce a variety of known toxins and yet still unidentified compounds. Visual observation of the raw water source does not necessarily reveal the presence of cyanobacteria, since e.g. Planktothrix may occur in masses in the deeper water layers. Monitoring of incoming water to the treatment plant and the treated drinking water using microscopical examination reveals if cyanobacteria are present in the raw water and if cyanobacterial cells break through the treatment process. Microscopical examination of raw and treated drinking water can easily be included in the regular monitoring at drinking water treatment plants. Cyanobacterial cells are easy to identify under microscope. Special expertise is needed for identification to species level, but this is not necessary in routine monitoring. The proposed monitoring schemes are based on scientific research and risk assessment. The cost of such monitoring is relatively low.