Management Of Cyanobacteria Research Articles

Harmonizing science and management options to reduce risks of cyanobacteria

Management of cyanobacteria has become an increasingly complex venture. Cyanobacteria risks have amplified as society moves forward in an era of accelerated global changes. The cyanobacteria management “pendulum” has progressively shifted from prevention to mitigation, with management considerations often put forth after bloom formation. A universal system (i.e., one-size-fits-all management) fails to provide a management path forward due to the inherent complexities of each lake. A tailored management plan is needed: the right species at the right time in the right place (i.e., the three Rs). The three Rs represent a customizable management strategy that is flexible and informed by advances in scientific understanding to lower cyanobacteria-associated risks. Identifying thresholds in risk tolerance, where thresholds are defined by community collectives, is essential to frame cyanobacteria management targets and to decide on what management interventions are warranted.

Monitoring of cyanobacteria using derivative spectrophotometry and improvement of the method detection limit by changing pathlength

Abstract Effective monitoring tools and methods are needed for the early detection and management of cyanobacteria in water bodies to minimize their harmful impacts on the environment and public health. This research investigated changing the cuvette pathlength (10-, 50-, and 100-mm) to improve the detection of cyanobacteria using UV-Vis spectrophotometry with subsequent application of derivative spectrophotometry and Savitzky-Golay (S-G) transformation. A non-toxigenic strain of blue-green cyanobacteria, Microcystis aeruginosa (CPCC 632), and a green algae strain for comparison, Chlorella vulgaris (CPCC 90), were studied in a wide range of concentrations (955,000 to 1855 cells/mL). In each concentration range, method detection limits were established with absorbance measurements and S-G first derivative of absorbance using 10-, 50-, and 100-mm cuvette pathlengths. Increasing the cuvette pathlength from 10 to 100 mm resulted in a 15-fold improvement in sensitivity with absorbance and a 13-fold improvement with S-G first derivative of absorbance for M. aeruginosa. Overall, adoption of 100 mm pathlength and application of S-G derivative spectra improved the method detection limit for M. aeruginosa from 337,398 to 4916 cells/mL, which is below the WHO guideline for low probability of adverse health effects (<20,000 cells/mL). Similarly, the detection limit for C. vulgaris was improved from 650,414 to 11,661 cells/mL. The results also showed that spectrophotometry could differentiate M. aeruginosa from C. vulgaris based on the variations in their pigment absorbance peaks.

Assessment of the Water Treatment Process’s Empirical Model Predictions for the Management of Aesthetic and Health Risks Associated with Cyanobacteria

Potentially toxic cyanobacteria have been increasingly detected worldwide in water supply systems in recent years. The management of cyanobacteria in source water and through drinking water treatment processes has been a focus of global research for over thirty years. However, despite the volume of research outcomes and the publication of guidance documents, gaps still exist in the knowledge base that inhibits the confident application of individual treatment strategies for the mitigation of aesthetic and health risks associated with cyanobacteria and their metabolites at the full-scale. The main objective of this project is to deliver a suite of tools and other resources to the water industry to support the implementation of a regulatory framework for the management of water quality for the assessment and management of aesthetic and toxicity risks associated with cyanobacteria. This study includes (1) the development of a guide (based on real-world examples) for treatment plant operators to perform plant audits and investigative sampling to assess the risk associated with cyanobacteria in their plants, and validate the performance of existing unit processes, and (2) the validation of a treatment model that can be applied at any plant and used to as a guide to the removals of cyanobacteria and metabolites and the expected quality of treated water under a range of challenges from cyanobacteria. Full-scale sampling was undertaken at three Australian regions in 14 water treatment plants to validate the model. The results presented in this paper represent a comprehensive database of full-scale removal efficiencies of 2-methylisoborneol (MIB) and geosmin for a range of water quality and treatment processes. The major findings and conclusions from this project include: (1) the investigative sampling procedures developed are effective and have been successfully applied by utilities; and (2) while routine monitoring data is important, investigative sampling within the water treatment plant provides more detailed and insightful information about the effectiveness of unit processes within the plant. This paper also identifies the knowledge gaps and needs for further studies.

Alternative Methods for Analysis of Cyanobacterial Populations in Drinking Water Supplies: Fluorometric and Toxicological Applications Using Phycocyanin

The management of cyanobacteria and potential exposure to associated biotoxins requires the allocation of scarce resources across a range of freshwater resources within various jurisdictions. Cost effective and reliable methods for sample processing and analysis form the foundation of the protocol yielding reliable data from which to derive important decisions. In this study the utilization of new methods to collect, process and analyze samples enhanced our ability to evaluate cyanobacterial populations. Extraction of phycocyanin using the single freeze thaw method provided more accurate and precise measurements (CV 4.7% and 6.4%), offering a simple and cost-effective means to overcome the influence of morphological variability. In-vacuo concentration of samples prior to ELISA analysis provided a detection limit of 0.001 μg·L−1 MC. Fractionation of samples (−1) = −0.279 + (1.368 ∗ Log PC (μg·L−1) while in an Aphanizomemon spp. dominant system Log MC (ng·L−1) = 0.385 + (0.449 ∗ Log PC (μg·L−1). These methods and sampling protocol could be used in other aquatic systems across a broader regional landscape to estimate the levels of microcystins.

Attempted management of cyanobacteria by Phoslock (lanthanum-modified clay) in Canadian lakes: water quality results and predictions

ABSTRACTNürnberg GK. 2017. Attempted management of cyanobacteria by Phoslock (lanthanum-modified clay) in Canadian lakes: water quality results and predictions. Lake Reserv Manage. 33:163–170.When internal phosphorus (P) loading from the bottom sediments outweighs external P inputs to lakes, lake water quality and cyanobacteria blooms will not respond to external measures alone and therefore require an in-lake restoration treatment. Lake characteristics and governmental regulations do not permit a random choice of such methods. A treatment developed by an Australian research institute (CSIRO) more than 15 years ago has recently been introduced to Canada and is licensed in Ontario. The lake water treatment consists of the application of a phosphate adsorbing and sediment capping agent called Phoslock in North America, a clay (bentonite) that has been systematically amended by the phosphate adsorbing element lanthanum. When applied, Phoslock sinks to the lake bottom where it intercepts the upward flux of internal load from sediment P release. Although the number of monitored Canadian applications is still small, suggestions to optimize restoration effects can be made, including the avoidance of high flushing during application, system isolation, and timing to coincide with high levels of inorganic P in the lake water. Initial results in at least 2 cases (Swan Lake, City of Markham, Greater Toronto Area; and Henderson Lake, Lethbridge, Alberta) were promising despite the unexpected external P input from waterfowl and possibly other external sources. Other applications are planned in a Quebec lake and are being discussed in several other provinces.

International Guidance Manual for the Management of Toxic Cyanobacteria

Cyanobacteria are a concern for water authorities worldwide as their persistence in water supplies causes numerous problems for water treatment plants. However, the major concern associated with the presence of cyanobacteria is the metabolites they produce, taste and odour compounds, particularly 2-methyl isoborneol and geosmin, and a range of toxic compounds known collectively as algal toxins, or cyanotoxins. The management of cyanobacteria and cyanotoxins is one of the priority issues and this international guidance manual aims to consolidate the available knowledge and information: This manual is a user-friendly document that can be accessed on several levels, from basic information for the water quality manager who knows very little about cyanobacteria, to those requiring more detailed guidance on, for example, source water management methods, or doses of activated carbon required to reduce toxin concentration to below the WHO guideline. It is hoped this manual is accessed by water utilities world-wide, and feedback on its application will be used to update and implement revisions to maintain and enhance its usefulness to the international water industry. This title belongs to GWRC Report Series . ISBN: 9781780401355 (eBook)

Everything a Manager Should Know About Algal Toxins but Was Afraid to Ask

The increased number of events of surface water eutrophication and utilities' increased use of surface water as a source have raised awareness of freshwater algae. An algal bloom can create several problems in drinking water treatment such as taste and odor compounds, shortened filter run times, increased chemical usage, and production of toxins. Evaluating individual treatment process units as well as the complete process for algae and toxin removal will allow a utility to make more responsible decisions and prepare for an event. Algae and their toxins can be treated provided the utility has implemented an algae‐monitoring program and developed a strategic plan for treatment. This aticle discusses a simple and rapid assessment of the degree of protection against algal toxins, monitoring and management of cyanobacteria in drinking water supplies, treatment barriers of cyanobacteria and their toxins, treatment used to remove cells, and dissolved algal toxins.