In Vitro Trial of Lake Guard Copper-Based Algaecide Efficacy In
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IN VITRO TRIAL OF LAKE GUARD COPPER-BASED ALGAECIDE EFFICACY IN MANAGING ALGAL BLOOMS USING FIELD SAMPLED ORGANISMS A Thesis Presented to The Graduate Faculty of The University of Akron In Partial Fulfillment Of the Requirements for the Degree Master of Science David S. Lowry May 2021 IN VITRO TRIAL OF LAKE GUARD COPPER-BASED ALGAECIDE EFFICACY IN MANAGING ALGAL BLOOMS USING FIELD SAMPLED ORGANISMS David S. Lowry Thesis Approved: Accepted: ______________________________ ___________________________ Co-Advisor Department Chair Dr. Teresa J. Cutright Dr. Stephen Weeks ______________________________ ___________________________ Co-Advisor Interim Dean of the College Dr. John M. Senko Dr. Joe Urgo ______________________________ ___________________________ Committee Member Interim Director, Graduate School Dr. Donald W. Ott Dr. Marnie Saunders ___________________________ Date ii ABSTRACT Harmful algal blooms, most notably toxic cyanobacterial blooms, pose serious threats to water management and the environment. Copper algaecides, having a long history of use as a biocide in controlling algal blooms, is also toxic to other aquatic organisms and requires responsible application. With the majority of algal blooms occurring at a waterbody’s surface, new copper formulations and application methods are continually developed to increase targeted action. Lake Guard Blue (BlueGreen Water Technologies Ltd.) was formulated as a floating copper product to increase upper water strata exposure. This product is conveyed as slow releasing and capable of movement in tandem with surface blooming algae through wind and water motion. Copper-based algaecide Lake Guard Blue was used in bench-scale experiments to determine efficacy in reducing cyanobacterial bloom densities. The product does not currently have EPA approval for use within the U.S. but is used elsewhere on the international market. Bench-scale experiments using environmentally sampled water with indigenous organisms were treated in triplicate with two dosages of Lake Guard Blue in parallel with EPA approved Cutrine Ultra (Arch Chemicals Inc.). Cyanobacteria populations were collected in the field at >10,000 cells/ml to be adjusted in the laboratory to 10,000 ±1000 cells/ml in accordance with the minimal action level required by the EPA for algaecide application. Lake Guard manufacture’s recommended maximum dose of 17.8 lbs/acre was determined to contain more elemental copper than is allowable under current iii EPA regulations. A new full dose was calculated to 8.45 lbs/acre Lake Guard Blue for experimentation, translating to 2.49 mg/L Cu. Simultaneously, a copper equivalent dose of 0.94 mg/L Cu was established for Lake Guard Blue to match that of the recommended dose for comparative algaecide Cutrine Ultra. In total seven experiments were performed with five lakes sourced for water, two of which were sampled twice. These lakes, all located in northeast Ohio, included three within the Cleveland Metro Parks (Camp Forbes, Ledge Lake & Isaac Lake), Hudson Springs Lake and a drinking water reservoir, Lake Rockwell. Although the new Lake Guard full dose did reduce cyanobacteria density over time, it was observed to be far too impactful to both cyanobacteria and to all other non-target algae in all experiments. Collectively, mixed cyanobacteria populations in reactors that included genera such as Microcystis, Anabaena and Oscillatoria, showed dramatic reductions in average cell density from 76.45 - 96.84% by day 2 following full dose Lake Guard application and declined further through day 14. Application of the lower Lake Guard dose was similarly impactful on cyanobacteria density however varied widely from 59.16 - 95.28% compared to 33.26 – 92.22% seen in the copper equivalent Cutrine Ultra by day 2. Reductions also continued for the lower Lake Guard dose as in the full dose but again with the same wide variability. Similar extreme reductions in chl-a concentration for full dose Lake Guard were observed by day 2 but with a broader range of 35.89 – 81.74%. This was not much better for the lower Lake Guard dose with an average decrease ranging 40.82 – 86.54% by day 2. In both cases, further declines continued out to day 14. Non-target members of diverse algal communities in both Lake Guard groups that were easily located at the start of experimentation were not detected in microscopy samples by day 14. Genera of iv Chlorophyceae including Elakatothrix and Ankistrodesmus were less often detected by day 14 compared to those species of Pediastrum, Scenedesmus and Radiococcus. In contrast, Cutrine Ultra had considerable variation in its impact on chl-a concentration by day 2 ranging from an average increase of 18.20% to an average decrease of 77.82%. Further, while rebounds in chl-a concentration occurred in none of the Lake Guard experiments, Cutrine Ultra showed signs of non-target algae rebounding by day 14 with some experiments yielding average increases in chl-a concentration from that of day 2 levels ranging 113.3 – 2876.49% by the end of the 14 day experiments. Based on results of these experiments, it is not recommended to use Like Guard Blue at its current manufacture’s recommended dose and a lower dose should be evaluated. Lake Guard Blue would benefit from further laboratory studies. Monoculture and controlled mixed culture studies are among the highest recommended of those outlined by the results of this study to determine species specific impacts. Additional insights should be drawn about the product’s rate of copper release and ability to degrade in the environment as potentially hazardous debris remained at the end of 14 day experimentation. v ACKNOWLEDGEMENTS I would like to thank my co-advisors, Dr. Teresa J. Cutright and Dr. John M. Senko, and committee member Dr. Donald W. Ott for their guidance through my graduate work. I would also like to thank may other professionals and fellow graduate students I have worked with along with way, contributing to my knowledge and teaching me laboratory skills that only come from true experience. Particularly, Dr. Robert B. Miller, Dr. Matthew E. Jennings, Angela Alicea-Serrano M.Sc., Dr. Elizabeth A. Crafton, Robert Holmes and Mr. Thomas J. Quick. I also extend my deepest thanks to my family for their endless love and support during my time at The University of Akron. The following work was made possible through funding by the Cleveland Foundation and water sourced from the Cleveland Metro Parks, Hudson Springs Park and Lake Rockwell. This project was made possible through their steadfast cooperation. vi TABLE OF CONTENTS PAGE LIST OF TABLES ........................................................................................................ XII LIST OF FIGURES ...................................................................................................... XIII CHAPTER I ........................................................................................................................ 1 INTRODUCTION AND OBJECTIVES ........................................................................ 1 1.1 Causes and impacts of harmful algal blooms (HABs) ........................................ 1 1.2 Algae mitigation and the use of copper as an algaecide ....................................... 3 1.3 Research Objectives .............................................................................................. 6 CHAPTER II ....................................................................................................................... 8 LITERATURE REVIEW................................................................................................ 8 2.1 Harmful Algal Blooms (HABs) ............................................................................ 8 2.2 Cyanobacteria Harmful Algal Blooms (cHABs) and Cyanotoxins ...................... 8 2.2.2 Eutrophication and Climate Change ................................................................ 10 2.3 CyanoHAB management and the use of algaecides ........................................... 12 2.3.1 Copper Algaecides ........................................................................................... 12 CHAPTER III.................................................................................................................... 15 MATERIALS & METHODS ........................................................................................ 15 3.1 Site Collection ..................................................................................................... 15 vii 3.2 Collection Site Descriptions................................................................................ 16 3.3 HAB simulated reactors ...................................................................................... 19 3.4 Experimental design ............................................................................................ 20 3.5 Microscopy and identification methods .............................................................. 22 3.6 Statistical Analysis .............................................................................................. 23 CHAPTER IV ................................................................................................................... 24 RESULTS & DISCUSSION ......................................................................................... 24 4.1 Lake Rockwell (7.23.2019 & 8.12.2019) treatments vs. control ........................ 24 4.1.1 Incorporation of Lower Dose of Lake Guard .......................................... 24 4.1.2 Lake