Monitoring, Photochemical Fate, and Oxidative Degradation by UV and Solar-based Catalytic Technologies of Cyanotoxins in Freshwater EstuariesEPA Grant Number: R833223
Title: Monitoring, Photochemical Fate, and Oxidative Degradation by UV and Solar-based Catalytic Technologies of Cyanotoxins in Freshwater Estuaries
Investigators: Dionysiou, Dionysios D. , Miller, Cheryl L. , Deis, Donald R. , Westrick, Judy , O'Shea, Kevin
Institution: University of Cincinnati , PBS&J , Florida International University , Lake Superior State University
Current Institution: University of Cincinnati , Florida International University , Green Water Laboratories/CyanoLab , Lake Superior State University , PBS&J
EPA Project Officer: Klieforth, Barbara I
Project Period: April 1, 2007 through March 31, 2010
Project Amount: $679,589
RFA: Development and Evaluation of Innovative Approaches for the Quantitative Assessment of Pathogens in Drinking Water (2005) RFA Text | Recipients Lists
Research Category: Drinking Water , Water
The increase of harmful algal blooms (HABs) in freshwater estuaries, especially in the Great Lakes and Florida, is a source of growing concern. The presence of high concentrations of harmful cyanotoxins from HABs in drinking water supplies is a serious threat to human and environmental health. One of the major challenges in assessing the associated health risks is to better understand the environmental/photochemical fate of these toxins. There is an urgent need to develop and identify effective water treatment technologies to eliminate cyanotoxins from drinking water. The overall objective of this study is to develop an active collaboration to monitor, determine the photochemical fate and evaluate potential photochemical (UV, and solar based) treatment technologies for cyanotoxins.
The specific objectives of the proposal are to: (1) evaluate the photolytic degradation of microcystins along a salinity and dissolved organic carbon (DOC) gradient and identify the fate and partitioning of microcystins in the estuarine portion of the lower St. Johns River in Florida and several locations in the Great Lakes; (2) investigate the mechanisms of the photo-transformations of cyanotoxins present in synthetic solutions and samples from the Great Lakes and Florida by visible and solar irradiation; (3) explore solar-driven catalytic systems for the destruction of cyanotoxins in water; and (4) investigate the fate of cyanotoxins under germicidal action UV (254 nm) (low pressure lamps) or broader spectrum (medium pressure lamps) at various levels of UV fluence in consideration with the presence of UV disinfection systems in several drinking water treatment plants.
The proposed work will be accomplished through four main research tasks: (1) monitoring of HAB and sampling in the Great Lakes; (2) monitoring of HAB and studying photochemical effects, reaction products and their toxicity along several locations of St. Johns River in Florida; (3) performing fundamental studies on the photochemical fate of microcystins, nodularin, and cylindrospermopsin, including studies to identify reaction intermediates and elucidate reaction pathways; and (4) synthesizing and evaluating novel catalytic systems for the destruction of cyanotoxins with solar light. In these studies, several cyanobacterial hotspots in the Great Lakes and Florida will be surveyed as monitoring sites for microcystin and cylindrospermopsin. Once HABs are identified, samples will be collected and analyzed for cyanotoxins and their photochemical fate will be evaluated as a function of the environmental factors. The role of important water quality parameters and process conditions on the photolysis and photooxidation of the identified cyanotoxins will be established using product studies and classical photochemical experimentation. UV, visible and solar irradiation sources will be used to determine the role of wavelength and flux on the photochemical fate and degradation of the cyanotoxins. The specific catalyst that will be used in the study will be synthesized using novel nanotechnological approaches and will be optimized for the destruction of cyanotoxins in water using solar light.
The results will provide a fundamental understanding of the photochemical fate of the target cyanotoxins. Such investigations are critical to the development of cost-efficient technologies for treatment of water contaminated with cyanotoxins. The results of this work will provide the data required for (i) a better understanding of the interactions of selected cyanotoxins with light and their photochemical fate in freshwater estuaries, (ii) evaluating the role of novel catalytic materials to destroy cyanotoxins in water as an approach to develop engineering technologies utilizing solar radiation as a renewable source of light, and (iii) determining the magnitude of photochemical transformation of cyanotoxins under specific range of UV radiation fluence in consideration with the UV fluence applied in typical UV disinfection treatment units or required to inactivate specific pathogenic microorganisms.