Current Research Projects

  1. Human Metabolites of Algal Hepatotoxins

CURRENT PILOT PROJECTS

  1. Use of Phage Display Techniques for the Detection of Algal Toxins.
  2. Interactions of Toxic Metals with Algal Toxins derived from Harmful Algal Bloom.
  3. Transgenic Zebrafish Based on Inducible Cytochrome P450 as Reporters for HAB Toxin Detection.

COMPLETED RESEARCH PROJECT

  1. New Toxins from Algae and Cyanobacteria

COMPLETED PILOT PROJECTS

  1. Identification of Developmental Toxins from Cyanobacteria
  2. Molecular Approaches to Monitor Toxic Dinoflagellates
  3. MD/ NMR Characterization of the Internal Motions of Peptide Toxins
  4. Impacts of Arsenic from CCA Treated Wood within Marine and Terrestial Environments
  5. Treatment of Microcystins by Ultrasonic Irradiation
  6. Cyanobacteria, their Toxins and Recreational Exposure
  7. An Ion Exchange Approach for the Design of Toxic Metal Ion Ligands and Sensors for Aquatic Environments
  8. Transmission and Storage of Brevetoxins in Coastal Foods Webs.
  9. Microbial Biodegradation of Brevetoxins -Isolation and Screening of Marine Bacteria
  10. Leachability and Harmful Effects of Arsenic, Copper, and Chromium Associated with CA-treated Wood
  11. Adsorption and oxidation of arsenic species on metal oxide surfaces

NOTE: For reprints or pdfs of articles about these projects please contact the authors by email.

CURRENT RESEARCH PROJECT
Human Metabolites of Algal Hepatotoxins

Kathleen Rein, Chemistry and Biochemistry, Florida International University
Douglas Crawford, Marine Biology and Fisheries, University of Miami
Lynne Fieber, Marine Biology and Fisheries, University of Miami

Microcystin-LR and okadaic acid belong to a family of natural toxins which localize to the liver, inhibit the serine-threonine protein phosphatases PP1 and PP2A, inducing severe detrimental effects on the liver. These compounds are considered acute hepatotoxins and carcinogens. Little information with respect to the metabolism of these two toxins is available. While glutathione and cysteine conjugates of microcystin-LR have been identified in vertebrates and invertebrates, no phase I metabolites have been identified. Recent reports suggest that okadaic acid is metabolically activated to genotoxic products, yet no metabolites of okadaic acid have been identified in vertebrates. The long-term goal of this research is to develop a thorough understanding of the metabolic fate of the two hepatotoxins and to understand how and if xenobiotic metabolizing enzymes are regulated by these environmental toxins and how factors such as age, gender cytochrome P450 (CYP) polymorphisms, tobacco use, diet, and other environmental factors will influence toxicity by affecting the expression and activity of xenobiotic metabolizing enzymes and hence the profile metabolites formed. The objective of this proposal is to generate human metabolites of microcystin-LR and okadaic acid synthetically and enzymatically, using human recombinant xenobiotic metabolizing enzymes, and to create an “average” metabolite profile for each toxin derived from human primary hepatocytes. We will also examine the effect of parent toxins and individual metabolites on a human liver cell line, HepG2. We will further evaluate the influence of the parent toxins and selected metabolites on gene expression in BALB/c mice. The central hypothesis of the proposed research is that microcystin-LR and okadaic acid may be metabolized by xenobiotic metabolizing enzymes, and that metabolites diversify the effects of exposure to the parent toxins by exhibiting different biological activities in their respective target organs. This research is innovative because a systematic analysis of MC-LR and OA metabolites and their toxicities has not been undertaken. This work is significant because, diet, environment, gender, age, health, prior exposure to xenobiotics and genetic polymorphisms in liver xenobiotic metabolizing enzymes in humans will influence metabolism and susceptibility in different populations. This work will immediately link a xenobiotic metabolizing enzyme, such as a cytochrome P450 (CYP) with a specific metabolite and will evaluate the toxicity of individual metabolites.

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CURRENT PILOT PROJECTS
Molecular Monitoring and Rapid-Response Characterization of Karenia brevis

Todd LaJeunesse, Department of Biology, Florida International University
Gary Hitchcock, Marine Biology and Fisheries, University of Miami

The annual occurrence of Karenia brevis in the Gulf of Mexico is one of the most significant harmful algal blooms (HABs) in the coastal waters of the United States. This HAB species has a large economic, health, and environmental impact on Gulf coast communities, especially in Florida, through massive fish kills, deaths of marine mammals and birds, human consumption of toxin-contaminated seafood, and respiratory effects from aerosolized toxins. Over the past few decades the incidence of K. brevis blooms appears to be increasing in both frequency and duration. Current government-mandated programs for monitoring this HAB species must rely on microscopic cell counts. These counts are time consuming, have low sample through-put, and require highly-skilled microscopists who are experts at identifying and enumerating Karenia brevis cells of varying morphologies in complex natural phytoplankton assemblages. There is consensus among HAB researchers and public health professionals that monitoring efforts for HABs must evolve towards the use of rapid, accurate, sensitive, and objective molecular-based detection and quantitation methods.

The proposed project will first utilize a combination of molecular techniques, such as Fluorescent In Situ Hybridization (FISH) and real-time quantitative polymerase chain reaction (qPCR), with traditional methods (light and fluorescent microscopy) to enumerate Karenia brevis cells in laboratory cultures. The objective of this initial phase is to test the efficacy of, and where feasible optimize, molecular methodologies with a short (3-5 hour) processing time for use in natural populations. Second, we will apply a combination of metabolic measurements (cell division, photosynthesis and respiration rates) and flow cytometry methodologies in cultures, and then natural popualtiosn, to improve our understanding of how environmental factors influence the metabolic state of K. brevis. Third, we will attempt to relate these indices to environmental parameters. The ultimate objective of this research is to facilitate the idenitfication and enumeration of this HAB species, and develop near real-time indices to assess the metabolic state of Karenia brevis in various stages of bloom development.

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Microbial Biodegradation of Brevetoxins -Isolation and Screening of Marine Bacteria

Krish Jayachandran, Environmental Studies, Florida International University
Lynne Fieber, Marine Biology and Fisheries, University of Miami

Frequent occurrence of ‘red tide’, a type of harmful algal bloom, has become a threat to the health and survival of marine animals in the Florida Gulf Coast. The toxic blooms also negatively impact the health and economy of the human population living in these Gulf Coast shores. A dinoflagellate, Karenia brevis, is present in very high numbers in the red tide and is responsible for the production and release of brevetoxins. Brevetoxins are polyketide compounds with a polyether ladder structure and act as potent neurotoxins. Several studies have shown that bacteria are capable of biodegrading complex algal and fungal toxins in nature. We hypothesize that bacteria present in the brevetoxin production cultures of K. brevis and in the K. brevis blooms may have the potential to degrade brevetoxins released by K. brevis. Our long-term goal is to discover and develop natural biological agents for use as potential mitigation tools in the management of a broad range of environmental health problems. We plan to test our hypothesis by pursuing two specific aims: 1) Discover novel marine bacteria, or bacterial consortia, capable of degrading brevetoxin. 2) Isolate, characterize, and evaluate bacterial metabolites from the brevetoxin biodegradation process. The marine bacteria with potential brevetoxin biodegradation capabilities will be isolated by means of an enrichment technique and also by direct isolation. Individual isolates, as well as microbial consortia, will be tested for the ability to use brevetoxin as their sole carbon source for growth. The bacterial isolates from the screening showing efficient growth on brevetoxin will be used for further metabolic studies. The metabolites from the brevetoxin biodegradation process will be isolated, characterized, and tested using HPLC/PDA/MS, ELISA assay and whole cell sodium ion channel activity. This approach is innovative because it utilizes the naturally occurring ability of marine bacteria to detoxify or degrade a complex polyether algal toxin. The proposed research is significant because it is expected to advance and expand understanding of biochemical transformations of brevetoxin in the aqueous phase. This is an important and least studied area of brevetoxin research that has potential applicability in the development of novel strategies for management and monitoring of red tide events, leading to better health prospects for the people in the Florida Gulf Coast region

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Leachability and Harmful Effects of Arsenic, Copper, and Chromium Associated with CCA-treated Wood.

Yong Cai, Chemistry and Biochemistry , Florida International University
Helena Solo-Gabriele, Civil and Environmental Engineering, University of Miami
Lynne Fieber, Marine Biology and Fisheries, University of Miami

Health problems associated with exposure to arsenic (As) from chromated copper arsenate (CCA)-treated wood continue to command world attention. It has been demonstrated that, in addition to As, chromium (Cr) and copper (Cu) also leach at levels potentially toxic to aquatic organisms. Although considerable progress has been made in studying the toxicity of As, the harmful effects of these three elements in mixtures, leached simultaneously are currently unknown. The lack of this information remains one of the major obstacles to assess the potential effects of CCA-treated wood on human health. Our long-term goal is to characterize and ultimately reduce the human health risks associated with exposure to CCA. The principal objective of this research is to understand the leaching and human physiological effects (cell behavior and metabolism) of As, Cr, and Cu associated with CCA-treated wood. The objective will be accomplished by pursuing the following specific aims: (1) Investigate the leaching characteristics of all three toxic elements, As, Cr, and Cu from CCA-treated wood and from the affected soils; (2) Evaluate the effects on aspects of cell physiology of As, Cr, and Cu alone or in mixtures using a model based on human nerve cell cultures (cell lines such as NSC-34, SH-SY5Y, CATH.a, D384 and SK-N-MC); and 3) Determine the effects of soil properties on the cell effects of soil leachate. This study will be guided by the following hypotheses: (1) The potential physiological effects of the leachates associated with CCA-treated wood to human beings is affected by the presence of the three metals derived from CCA and interactions between them and low concentrations of As, Cr, and Cu in these leachates will affect critical aspects of cell metabolism; and (2) The leaching and potential effects of these elements from soils affected by CCA are altered by soil properties. It is expected that this research will provide new and essential information for assessing the effects of the leachates associated with CCA on human beings. These results will allow improved predictions of leaching of As, Cr, and Cu from CCA-treated wood and their transport through soils and, ultimately, evaluations of possible human health impacts associated with the release of these elements. Our results will, therefore, enable us to more accurately assess the environmental and human health impacts of As, Cr, and Cu pollution resulting from CCA applications.

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Adsorption and oxidation of aresenic species on metal oxide surfaces

Kevin O’Shea, Chemistry and Biochemistry, Florida International University
Angel Kaifer, Chemistry, University of Miami

The presence of arsenic in ground and surface water has prompted considerable research efforts toward understanding the health impact of arsenic ingestion, its environmental fate and transport, and its removal from potable water. Arsenic is considered a human carcinogen and drinking arsenic-contaminated water is linked to increased risk of diabetes, cardiovascular problems, hormonal disruption, cancer, DNA damage, and vascular diseases. Arsenic is often associated with metal oxides and humic materials in drinking water supplies. The working hypothesis for this research proposal is that the interactions, bonding and reactivity of arsenic on metal oxides play key roles in the bioavailability, toxicity, and effective remediation of arsenic. A fundamental knowledge of arsenic redox kinetics and adsorption properties is critical for understanding the health risks associated with the bioavailability of arsenic, the fate and transport of arsenic in the environment and for the optimization of treatment processes for the removal of arsenic species from drinking water.

The primary goal of the proposed study is to develop a fundamental understanding of the adsorption and oxidation of toxic arsenic on metal oxide surfaces using microscopic imaging, spectroscopy, and molecular manipulation techniques. Titanium and tin oxides will be used as the model metal oxides because of their potential applicability for the remediation of arsenic. The role of the metal oxide surface, and the kinetic and mechanistic parameters of titanium dioxide photocatalytic and tin oxide electrochemical remediation (oxidation and adsorption) of arsenic species will be established. The parameters established from the proposed studies are critical to the development of effective technologies for the treatment of arsenic contaminated waters. The long-term goal of the proposed research is to establish the mechanisms that govern the adsorption, reactions and release of arsenic from metal oxide surfaces. We expect the data generated from these studies can be input into environmental risk models that evaluate the probability of the health effects of ingestion of arsenic contaminated water by animals and humans.

Papers Published on this Project

Xu, T.; Kamat, P.V.; O’Shea, K.E. 2005. Mechanistic Evaluation of Arsenic Oxidation in TiO2 Assited Photocatalysis”, J. Phys. Chem. A , 109, 907.

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COMPLETED RESEARCH PROJECT
New Toxins from Algae and Cyanobacteria

Kathleen S. Rein, Department of Chemistry, Florida International University
Robert Gawley, Department of Chemistry, University of Miami

The aims of this project are two-fold. First we shall identify and characterize new toxins, produced by algae and cyanobacteria, found in Florida's aquatic environments. Florida waters harbor over sixty toxic or potentially toxic microorganisms. These toxic microorganisms have significant impacts on public health, recreation, tourism, wildlife and local economies. Gymnodinium breve blooms annually on the West Coast of Florida causing closure of shellfish beds to prevent the occurrence of neurotoxic shellfish poisoning. Cyanobacterial blooms are becoming increasingly frequent in freshwater lakes, making recreational use hazardous. In addition to these well-known and well-characterized toxin-producing organisms, other toxic microorganisms are present for which toxins have yet to be identified. This proposal will focus on the identification of these as yet uncharacterized toxins. Prior to mass culturing, small scale cultures and assemblages will be screened by RT-PCR for the expression of biosynthetic capability. Specifically, flagellates will be screened for polyketide synthase gene expression, while cyanobacteria will be screened for non-ribosomal peptide biosynthesis. New toxins will be isolated by bioassy guided fractionation using a variety of screening methods.
Second, the role of associated bacteria in dinoflagellate toxin biosynthesis will be examined. Since many dinoflagellate cultures have not been successfully maintained axenically, the ultimate origins of the toxins remains a topic of ongoing debate. The existence of toxic and-not toxic strains of dinoflagellates and the sudden unexplained loss of toxicity of dinoflagellates in culture has led to speculation that associated bacteria are responsible for toxin biosynthesis. We have isolated bacteria from dinoflagellate cultures that carry polyketide synthase encoding genes, but express them only in the presence of dinoflagellates. The role of these bacteria in the biosynthesis of dinoflagellate derived polyketides will be examined.

Papers Published on this Project

An, T.; Kumar, T. K. S.; Wang, M.; Liu, L.; Lay, J. O. Jr.; Liyanage, R.; Berry, J.; Gantar, M.; Marks, V.; Gawley, R. E.; Rein, K. S. 2007. Structures of Pahayokolides A and B, Two Cyclic Peptides from a Lyngbya sp. J. Nat. Prod. 70(5) 730-735.

Snyder, R. V.; Guerrero, M. A.; Sinigalliano, C. D.; Winshell, J.; Perez, R.; Lopez, J. V.; and Rein, K. S. 2005. Localization of polyketide synthase encoding genes to the toxic dinoflagellate Karenia brevis. Phytochemistry, 66, 1767-1780. Click to Download PDF

Berry, J. P.; Gantar, M.; Gawley, R. E.; Wang, M.; Rein, K. S. 2004. Pharmacology and Toxicology of Pahayokolide A, a Bioactive Metabolite from a Freshwater Species of Lyngbya Isolated from the Florida Everglades. Comp. Biochem. Phys. Prt C. 139, 231-238.

Berry, J. P., Gantar, M.; Gawley, R. E.; Rein, K. S. 2004. Isolation of bioactive metabolites from a Lyngbya species isolated from periphyton of the Florida Everglades. pp. 192-194. In K. A. Steidinger, J. H. Landsberg, C. R. Tomas and G. A. Vargo (eds.) Harmful Algae, 2002. Florida Fish and Wildlife Conservation Commission, Florida Institute of Oceanography, and Intergovernmental Oceanographic Commission of UNESCO.

Rein, K. S.; Snyder, R. V. Biosynthesis of Polyketide Metabolites by Dinoflagellates. 2006, Adv. Appl. Micro. 59, 93 – 126.

Snyder, Richard V.; Guerrero, Maria A.; Sinigalliano, Christopher D.; Winshell, Jamie; Perez, Roberto; Lopez, Jose V.; Rein, Kathleen S. (2005), “Localization of polyketide synthase encoding genes to the toxic dinoflagellate Karenia brevis”. Phytochemistry 66(15), 1767-1780.


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COMPLETED PILOT PROJECTS
Identification of Developmental Toxins from Cyanobacteria

Miroslav Gantar Department of Biological Sciences, Florida International University
John Berry Department of Chemistry, University of Miami

Michael Schmale Department of Marine Biology and Fisheries, University of Miami
This project utilizes the zebrafish embryo as a model of vertebrate development to identify and characterize developmental toxins from Cyanobacteria (or “blue-green algae”). Found in diverse environments worldwide, the Cyanobacteria represent a group of photosynthetic prokaryotes of which many are known to produce potent toxins. Humans and animals can be exposed to such toxins in aquatic environments through various routes including skin contact, ingestion, inhalation and haemodialysis, and increasing eutrophication of surface water bodies may be leading to increased concentrations of these toxins in drinking and recreational waters. A 2001 study, for example, of drinking water sources that supply 185,000 residents in Central Florida revealed the cyanobacterial toxin, microcystin, at levels up to five-times the safe limit recommended by the WHO (Orlando Sentinel, May 27, 2001). Effects of exposure of humans and animals to cyanobacterial toxins, however, are not well understood. Many of the cyanobacterial toxins have recognized cytotoxic, or otherwise inhibitory and/or promotive effects of on cellular proliferation. As such, it is conceivable that the exposure to even low levels of cyanobacterial toxins may lead to dysfunction in development of both human and animal embryos. Specifically, this research utilizes cultures of cyanobacteria from the Everglades and other freshwater sources in South Florida, isolated and maintained as part of the FIU ARCH Algal Toxins/Culture Facility Core. Assessment of the development of zebrafish embryos exposed to extracts from these cultures is used as an indicator to screen Cyanobacterial isolates for those which produce metabolites, including both described and currently undescribed toxins, that inhibit developmental pathways. In the case of previously undescribed toxins from these isolates, active compounds will be isolated by bioassay-guided fractionation (using the zebrafish embryo assay), and chemically characterized. Additionally, the zebrafish model can be used to characterize the targets and modes-of-action of these toxins, and more generally as a predictor of environmental health aspects associated with cyanobacterial toxins. Thus, this research provides an important interface with other research projects, as well as the overall research goals, of the FIU ARCH program as a model of the environmental risks associated with freshwater of cyanobacteria and their toxins.

Papers Published on this Project

Berry, John P., Gibbs, P. D. L., Gantar, M. and Schmale, M. C. 2007, Identification of developmental toxins from marine and freshwater algae using the zebrafish embryo as a model of vertebrate development. Comp. Biochem. Physiol. C Toxicol. Pharmacol., 145 (1): 61-72.

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Molecular Approaches to Monitor Toxic Dinoflagellates

Christopher D. Sinigalliano/Maria Guerrero, Southeast Environmental Research Center, Florida International University Jack Fell, Department of Marine Biology and Fisheries, University of Miami

The long term goals of this ARCH pilot project is to develop, optimize, and assess the effectiveness of a set of molecular methods for the detection and monitoring of toxic dinoflagellates among the epiphyton and free-living communities of microorganisms in coastal waters. As a group, these toxic dinoflagellates cause a variety of public health problems, including toxic seafood and shellfish poisoning, marine animal and bird kills, respiratory distress in humans, "red tide" fish kills, etc. Such toxic microorganisms are particularly common in Florida coastal waters. The State of Florida's Harmful Algal Bloom (HAB) Task Force has identified a critical need for the development of new technologies and approaches (particularly molecular probes) to monitor these toxins and the organisms that produce them, and how environmental variables affect their impact on public health and environmental quality. Particularly in the case of ciguatera HABs, there is a need to develop accurate and rapid methods to survey and monitor Florida waters for ciguateric dinoflagellate species and hot spots, and to test for the presence of their toxins.

Specifically, this project will involve the development and field trials of assays combining genetic labeling, immunological labeling, and flow cytometry for the enumeration and cell sorting of dinoflagellate cells producing toxins of public health concern, such as ciguatoxins, maitotoxins, gambiertoxins, brevetoxins, and okadaic acid. Particular interest will focus on the detection of Karenia brevis causing "red tide", Gambierdiscus species causing ciguatera food poisoning, and on toxin-producing Prorocentrum species. Molecular assays will be developed to monitor these toxic dinoflagellates and to examine their associated bacteria, by targeting both ribosomal RNA genes and genes for polyketide synthase (PKS). Such molecular probes for Prorocentrum lima have already been developed by our group and successfully utilized with preliminary in vitro studies. The work proposed here may also serve as a model for other toxic polyketide-producing marine microorganisms. This project will take three different approaches to investigate the presence and toxic activity of these marine dinoflagellates: 1) in vitro real-time PCR and probe macroarray assays of nucleic acid extracts from epiphyton and water column microbial communities, 2) flow cytometry (FCM) analysis using diagnostic light scatter and fluorescent properties of targeted dinoflagellate cells, and 3) fluorescent in situ hybridization and in situ PCR assays combined with FCM and fluorescent microscopy to assay probe-labeled cells. Multivariate analysis will be used to correlate this data to the extensive database of monthly biogeochemical data generated by our ongoing Water Quality Monitoring Network to identify the role and effect of environmental and anthropogenic factors influencing dinoflagellate toxicity in this region.

Papers Published on this Project

K.D. Goodwin, G. Scorzetti, S.A. Cotton, T.L. Kiesling, P.B. Ortner, and J.W. Fell. 2004. Detection of Karenia brevis by a Microtiter Plate Assay. In K. A. Steidinger, J. H. Landsberg, C. R. Tomas and G. A. Vargo (eds.) Harmful Algae, 2002. Florida Fish and Wildlife Conservation Commission, Florida Institute of Oceanography.

Goodwin, K.D.; Cotton, S.A.; Scorzetti, G.; Fell, J.W. 2005. A DNA hybridization assay to identify toxic dinoflagellates in coastal waters: detection of Karenia brevis in the Rookery Bay National Estuarine Research Reserve., Harmful Algae, 4, 411-422

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MD/ NMR Characterization of the Internal Motions of Peptide Toxins

David Chatfield, Department of Chemistry, Florida International University
TK Harris, Department of Biochemistry, University of Miami

This project focuses on the internal motions of alpha-conotoxin GI, a 13-residue, cross-linked peptide. The analysis will combine 15N NMR relaxation measurements of the isotopically labeled peptide, from which motional parameters describing the peptide's backbone flexibility will be obtained; and molecular dynamics (MD) simulation, which will provide an atomic-level interpretation of the motions. The work is significant in three respects: (1) It will further our understanding of alpha-conotoxin GI's interaction with the acetylcholine receptor and the consequent toxicity. (2) This small yet conformationally restricted peptide is an excellent model for developing methods for interpreting NMR motional parameters in terms of mechanical and thermodynamic properties of biological molecules.. (3) Characterizing the flexibility of alpha-conotoxin GI may help guide efforts to use it as a drug model. In the first year of the project, the NMR characterization will be carried out. In the second and third years, MD simulations will be performed to address the following issues: What is the quantitative value of the backbone's conformational entropy? Does the pairwise correlation of bond vector motions affect the calculation of the conformational entropy significantly? With what larger-scale motions are backbone bond vector motions correlated? In addition, restrained MD simulations of unfolded conformers with the disulfide bonds severed are proposed in order to quantify selected contributions of the backbone's conformational entropy to the conformational entropy of folding. The methodology developed in the work on alpha-conotoxin GI will be also applied to microcystins, hepatotoxins.

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Impacts of Arsenic from CCA Treated Wood within Marine and Terrestial Environments

Yong Cai, Department of Chemistry, Florida International University Helena Solo-Gabriele, Department of Engineering, University of Miami

Limited information is available about the ultimate fate of the arsenic found in chromated copper arsenate (CCA) during the service life and disposal of the treated wood product. This lack of information coupled with the large quantity of arsenic currently in service associated with treated wood (130,000 tonnes estimated), results in a potential risk of human and ecological exposure. The toxicity of arsenic is strongly a function of the speciation of the metalloid, with the inorganic species being more toxic than the methylated forms. Within the inorganic forms, species that are characterized by a lower valence are the most toxic. The objectives of the current study are to evaluate the toxicity of arsenic in leachates from CCA-treated wood by measuring the species of arsenic that are leached from different environmental samples. A considerable effort will be placed on method development, which will expand the applicability of cartridges designed to preserve samples in the field. Leaching will be evaluated in both laboratory and field settings. Laboratory studies will focus on standardized leaching tests aimed at simulating the impacts of rainfall, seawater, and landfill conditions. Laboratory samples evaluated will include CCA-treated wood at various retention levels. Field work will focus on evaluating the impacts of decks and marine docks constructed of CCA-treated wood on the surrounding environment. Samples will be routinely analyzed for arsenite (As(III)), arsenate (As(V)), monomethylarsonic acid (MMAA), and dimethylarsinic acid (DMAA). Other arsenic species, if any, will be detected and quantified on a periodic basis. Metals species will be routinely measured in the dissolved phase and methods will be developed for measuring arsenic speciation within the particulate phase. Results will be used to estimate the total U.S. arsenic releases from CCA-treated wood structures. These data will be useful as inputs into environmental risk models that evaluate the probability of human disease or other environmental outcome associated with the use or disposal of CCA-treated wood.

Papers Published on this Project

Articles in Peer-reviewed Journals
Shibata, T., Solo-Gabriele, H., Fleming, L., Cai, Y. and Townsend, T. 2007. A mass balance approach for evaluating Leachable arsenic and chromium from an in-service CCA-treated wood structure. The Science of Total Environment. 372, 624-635.

Georgiadis, M.; Cai, Y.; Solo-Gabriele, H. 2005. Extraction of Arsenate and Arsenite Species from Soils and Sediments. Environmental Pollution. 141, 22-29.

Feng, M.; Schrlau, J.; Snyder, R.; Snyder, G.; Chen, M.; Cisar, J. and Cai, Y. 2005. Arsenic Transport and Transformation Associated with MSMA Application on a Golf Course Green. J. Agric. Food Chem. 53, 3556-3562.

Khan, B. I.; Solo-Gabriele, H. M.; Dubey, B. K.; Townsend, T. G.; Cai, Y. 2004. Arsenic Speciation of Solvent-Extracted Leachate from New and Weathered CCA-Treated Wood. Environ. Sci. Technol. 38, 4527-4534

Khan, B.; Jambeck, J.; Solo-Gabriele, H.; Townsend, T.; and Cai, Y. 2006. Release of Arsenic to the Environment from CCA-Treated Wood: Part I – Leaching and Speciation during Service. Environ. Sci. Technol. 993-994.

Khan, B.; Jambeck, J.; Solo-Gabriele, H.; Townsend, T.; and Cai, Y. 2005. Release of Arsenic to the Environment from CCA-Treated Wood: Part II – Leaching and Speciation during Disposal. Environ. Sci. Technol. 988-993.

Chen, Z., Cai, Y., Solo-Gabriele, H., Snyder, G.H., and Cisar, J.L., 2006. Interactions of Arsenic and the Dissolved Substances Derived from Turf Soils, Environmental Science & Technology, 40: 4659-4665.

Solo-Gabriele, H.M.; Townsend, T.G.; and Cai, Y. 2004. Environmental Impacts of CCA-Treated Wood Within Florida, USA. Proceedings of the Environmental Impacts of Preservative Treated Wood Conference, held in Orlando, Fl. Conference Sponsored by the Florida Center for Environmental Solutions located in Gainesville, FL. p. 57-70.

Shibata, T.; Solo-Gabriele, H.M.; Fleming, L.; Shalat, S.; Cai, Y.; Townsend, T. 2004. Leachable and Dislodgeable Arsenic and Chromium from In-Service CCA-Treated Wood. Proceedings of the Environmental Impacts of Preservative Treated Wood Conference, held in Orlando, Fl. Conference Sponsored by the Florida Center for Environmental Solutions located in Gainesville, FL. p. 335-351.

Articles as Book Chapters

Xu, T.; Cai, Y.; Mezyk, S.; O'Shea, K. E. 2005. The Roles of Hydroxyl Radical, Superoxide Anion Radical and Hydrogen Peroxide in the Oxidation of Arsenic by Ultrasonic Irradiation In Advances in Arsenic Research, Intergration of Expereimental and Observational Studies and Implications for Mitigation, O’Day, P.; Vlassopoulos, D.; Meng, X.; Benning, L. G., Eds; Symposium Series 915; American Chemical Society, Washington DC, 2005, Ch 24, 45(1), 335.

Cai, Y., Solo-Gabriele, H., Townsend, T., Khan, B., Georgiadis, M. and Dubey, B. 2006. Elemental Speciation and Environmental Importance Associated with Wood Treated with Chromated Copper Arsenate. In Environmental Impacts of Treated Wood, Chapter 7. Townsend and Solo-Gabriele Eds. Taylor & Francis, Boca Raton, pp117-137.
Shibata T, Solo-Gabriele HM, Fleming LE, Shalat SL, Cai Y, Townsend TG, 2005.

Potential arsenic exposure to children associated with in-service and recycled CCA-treated wood in tropical environments. In Environmental Exposure and Health, M.M. Aral, C.A. Brebbia, M.L. Maslia, and T. Sinks (eds.). WIT Transactions on Ecology and the Environment (ISSN 1743-3541), Vol 85: 349-365.

Link to Yong Cai's web site. http://www.fiu.edu/~ebacg/page7.html

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Treatment of Microcystins by Ultrasonic Irradiation

Kevin E. O'Shea, Department of Chemistry, Florida International University
Pat Walsh, Department of Marine Biology and Fisheries, University of Miami

Microcystins, a family of peptides produced primarily by freshwater cyanobacteria have lead to animal fatalities worldwide and represent a considerable health threat to humans. Their potential for causing both acute and chronic toxicity has prompted the need for extensive research into their detection, toxicology and removal from potable water. The goal of this research project is to assess the use of ultrasonic irradiation for the degradation of naturally occurring aquatic toxins, specifically microcystins. It is well established that ultrasonic irradiation of aqueous media can lead to the mineralization of a variety of organic substrates. Initial sonolytic experiments will be conducted on cyanobacteria to establish the extent that toxic microcystins are released into the water and/or destroyed under treatment conditions. Microcystins will be isolated from cyanobacteria cultures available through the toxin probes facility core of the ARCH program (director Professor Kathleen Rein). Aqueous matrix samples containing microcystins will be prepared from isolated material and treated with ultrasonic irradiation. The disappearance of microcystins will be monitored as a function of treatment time and initial concentrations. These degradation profiles will allow us to determine the kinetic parameters, which are useful for predictive tools and modeling parameters in the applications of water treatment.

Papers Published on this Project

Ultrasonically induced degradation of 2-methylisoborneol and geosmin. 2007, Weihua Song and Kevin E. O’Shea, Wat. Research, 41, 2672-2678
Hudder, A.; Song, W.; O’Shea, K. E.; Walsh, P. 2007, Toxicogenomic evaluation of microcystin-LR treated with ultrasonic irradiation Toxicology and Applied Pharmacology, 220, 357-363.

Song, Weihua; de la Cruz, Armah A.; Rein, Kathleen; O'Shea, Kevin E. 2006 Ultrasonically Induced Degradation of Microcystin-LR and -RR: Identification of Products, Effect of pH, Formation and Destruction of Peroxides. Environmental Science & Technology, 40(12), 3941-3946.

Song, W.; Teshiba, T.; Rein, K. S.; O’Shea, K. E. 2005. Ultrasonically induced degradation and detoxification of Microcystin-LR (Cyanobacterial toxin), Environ. Sci. Technol. 39 (16), 6300-6305.

N. Ben Abderrazik, A. Azmani, C. R’kiek, and K.E. O’Shea. 2005 Iron(II) Catalyzed Enhancement of Ultrasonic Induced Degradation of Diethylstibestrol (endrocrine disruptor), Catalysis Today, 101, 369-373.

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Cyanobacteria, their Toxins and Recreational Exposure

Miroslav Gantar, Department of Biology, Florida International University
Lora Fleming, Department of Marine Biology and Fisheries, University of Miami

Blue green algae (cyanobacteria) represent a diverse group of organisms that are common inhabitants of freshwater lakes and reservoirs, and produce potent natural toxins. Potential routes of exposure for these toxins are dermal, oral, and possibly inhalation; humans can be exposed through drinking water, as well as recreationally and occupationally. There have been case reports of severe morbidity and mortality in domestic animals through drinking contaminated water, but little epidemiologic research on the human health effects of cyanobacteria and their toxins.

Recently in Florida, cyanobacteria and their toxins have been identified in freshwater lakes and reservoirs, with growing media and community concern. This proposed research will be a prospective cohort study of recreational users in Florida freshwater lakes with and without toxic cyanobacteria. Participants will be evaluated by initial and follow up interview as to symptoms and exposures. Water samples taken on the day of exposure will identify organisms and toxins. Reported human symptoms will be used to identify cyanobacteria species of potential environmental health impact for future study by researchers involved in the isolation and cultivation of cyanobacteria. At the end of the study, study participants and recreational lake managers will receive outreach and education materials concerning the cyanobacteria, their toxins, and possible human health effects.

Stewart, I.; Webb, P. M.; Schluter, P. J.; Fleming, L. E.; Burns, J. W. Jr.; Gantar, M.; Baker, L. C.; Shaw, G. R. 2004. Accute effects of recreational exposure to freshwater cyanobacteria - a prospective epidemiology study, pp. 473-475. In K. A. Steidinger, J. H. Landsberg, C. R. Tomas and G. A. Vargo (eds.) Harmful Algae, 2002. Florida Fish and Wildlife Conservation Commission, Florida Institute of Oceanography, and Intergovernmental Oceanographic Commission of UNESCO. St. Petersburg, Florida, USA


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An Ion Exchange Approach for the Design of Toxic Metal Ion Ligands and Sensors for Aquatic Environments

Konstantinos Kavallieratos, Department of Chemistry, Florida International University
Frank Millero, Department of Marine and Atmospheric Chemistry, University of Miami
A new strategy for designing synthesizing and screening self-organized hosts for recognition and sensing of toxic metal salts is proposed. Ligand libraries formed from combinations of simple subunits, which may potentially bind toxic metal ion-guests, will be generated using single-pot methods. The most effective ligands will be contacted with aqueous phases containing the metal ion and will be identified by mass spectrometry. Pb(II), will be our primary target with Hg(II) and Cd(II) following. The identified hosts and their complexes will be characterized structurally and spectroscopically and their thermodynamic and kinetic stabilities will be compared to macrocyclic or acyclic systems that have been previously used with the goal to optimize them for ion-exchange separation and sensing applications. Fluorophore groups will be attached to the optimized building blocks and thus generate hosts with the ability for fluorescent sensing. Our strategy may be expanded for other cationic or anionic guests of importance in aquatic environments and offers a powerful tool for identifying simple, and efficient hosts, which may be synthetically available on multigram quantities.

Papers Published on this Project

Kavallieratos, K.; Rosenberg J. M.; Bryan, J. C. 2005, Pb(II) coordination and synergistic ion-exchange extraction by combinations of sulfonamide chelates and 2,2’-bipyridine. Inorg. Chem. 44, 2573-2575.

Kavallieratos, K.; Rosenberg, J. M.; Chen, W.-Z.; Ren, T. 2005, Selective Pb(II) extraction and fluorescent sensing by a bis-dansylamide ion-exchanger. J. Am. Chem. Soc. 127, 6514-6515.

Kavallieratos, K.; Sabucedo, A. J..; Pau, A. T.; Rodriguez, J. M. 2005, Detection of anionic adducts of sulfonamide receptors with Cl-, Br-, NO3- and I- by Atmospheric Pressure Chemical Ionization Mass Spectrometry. J. Am. Soc. Mass Spectrom. 16, 1377-1385.

Alvarado, R. J.; Rosenberg, J. M.; Andreu, A.; Bryan, J. C.; Chen, W.-Z.; Ren, T.; Kavallieratos, K. 2005. Structural insights into the coordination and extraction of Pb(II) by aryldisulfonamide ligands derived from o-phenylenediamine. Inorg. Chem. 44, 7951-7959.

Zhang, W., Cai, Y., and Kavallieratos, K. 2006. Investigation of disulfonamide ligands derived from o-phenylenediamine and their Pb(II) complexes by electrospray ionization mass spectrometry. Rapid Communications in Mass Spectrometry. 20, 305-308.

Luo, X. and Millero, F. 2007. Stability constants for the formation of lead chloride complexes as a function of temperature and ionic strength. Geochim. Cosmochim. Acta, 71, 326- 334.

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