Geochemical impacts from Hurricane Irma to a west Florida blackwater estuary
Jordon Beckler-1,2, Emily Buckley-2, Diane Santioanni-2, Sean Jones-2, Arielle O’Brien-2, Emily Hall-2, Elizabeth Yanuskiewicz-2, Martial Taillefert-3, Eric Milbrandt-4
1- FAU Harbor Branch Oceanographic Institute, 2 -Mote Marine Laboratory, 3- Georgia Tech, 4-Sanibel Captiva Conservation Foundation
With the recent passing of Hurricane Irma over southwest Florida, the Caloosahatchee Estuary and San Carlos Bay system experienced extremely low salinities, decreased water clarity, and severe hypoxia – an event unprecedented in both duration, extent, and areal coverage since continuous monitoring began in 2007. Coincidentally, we led a week-long geochemical field campaign that began on Sep. 25th 2017 and was the wet-season complement to a previous dry-season (low-flow) sampling effort in Dec. 2016. On several full estuary transects, we quantified the size partitioning of iron, nutrients, and carbon in surface and bottom waters, as well as the solid phase organic carbon and reactive iron hydroxide content in surface sediments. Further, sediment respiratory processes and flux rates were elucidated from sediment cores using Hg/Au voltammetric microelectrode profiling and core separation and wet-chemical analyses.
Conditions after the storm were drastically different than under low flow conditions. For example, surface water dissolved iron concentrations were an order of magnitude higher (~ 8 mM) than under low flow conditions. While organically-complexed iron(III) concentrations exceeded 5 mM, the sediment-derived diffusive fluxes, which dominated under low-flow conditions, were negligible after the hurricane. Indeed, an excess of organic carbon in sediments relative to reactive iron hydroxides favored sulfate reduction (and sulfide production) in lieu of dissimilatory iron reduction, sequestering pore water iron and the resulting sediment-derived iron flux. However, an additional >3 mM of surface water iron was observed in the reduced (+II) form, with concentration profiles indicating a complementary source from the upriver drainage basin or Lake Okeechobee. Interestingly, the Fe(II) was relatively less stable in the lower estuary, either because of flocculation processes or oxidation as hypoxic conditions lessened.
I finally speculate on potential links to a local sustained bloom of the Florida red tide species K. brevis that began a few weeks after the storm, as well as the potential resilience of this system and other Florida blackwater river estuaries to extreme weather events expected to increase in the future.
The Zebrafish as a Toxicological Model for Assessing Toxic Potential of Cyanobacteria in the Environment
John P. Berry
Department of Chemistry and Biochemistry, Florida International University
As ubiquitous components of marine, freshwater and coastal systems, and owing to their recognized production of a diversity of toxic or otherwise biologically active secondary metabolites, cyanobacteria (or "blue-green algae") are emerging as major environmental concerns with respect to human, animal and ecosystem health. In order to understand their contribution - as "toxins" - to environmental health concerns we have employed the zebrafish (Danio rerio), and particularly embryonic and larval stages of the species, as a toxicological model to identify, isolate and characterize bioactive metabolites from cyanobacteria. As a means of identifying possibly relevant cyanobacterial toxins, the zebrafish embryo has been used to screen a wide array of cyanobacterial isolates (i.e., cultures) and compounds, and has consequently identified numerous lead to possibly novel toxins. In turn, the model system has been used to both isolate and subsequently characterize several bioactive metabolites in relation to their possible role as environmental toxicants. Subsequently, and most recently, we have adapted state-of-the-art techniques based on nuclear magnetic resonance (NMR), and particularly, high-resolution magic angle spinning (HRMAS) NMR, to investigate in vivo effects of these toxic metabolites on metabolic profiles in the intact ebrafish embryo model toward understanding both pathways of toxicity, and possible biomarkers of toxin exposure. This approach will be specifically illustrated in reference to examples of both previously established toxins, and possibly emerging/novel toxins identified through this strategy.
Assessment of potential markers of waste in wetland-treated wastewater
Emily C. Heider and Joseph Welch
University of Central Florida
Wastewater treatment facilities are remarkably effective in the removal of anthropogenic chemical components (e.g. caffeine) in waste. Even so, some compounds are persistent despite treatment with bacterial degradation, UV light, ozonation, and chlorination at the treatment facilities. Effluent from wastewater treatment facilities contains high concentrations of nitrogen (N) and phosphorus (P), yet these can be remediated with secondary water treatment wetlands that use natural processes to remove N and P nutrients and promote the health of natural waterways downstream. The Orlando Easterly Wetland (OEW) is an example such water polishing; this facility receives approximately 15 million gallons of treated wastewater per day, and through plant uptake, sedimentation, precipitation and bacterial denitrification, nutrients in the water are drastically decreased before the outflow to the St. Johns River. This research seeks to quantify sucralose (an artificial sweetener) and uric acid (the product of purine catabolism in animals and humans) at the Orlando Easterly Wetlands (OEW), to determine if these markers of human waste persist through wetland water polishing processes. Additionally, the uric acid in the water was studied to determine if its concentration increased through the excretions of avian, reptilian, and aquatic species.
Encapsulation of High Surface Particulates into Sol-gel Matrix and Their Use in Environmental Pollution Mitigation
Abuzar Kabir, Cassie-Jo McBride, Kenneth G. Furton.
Florida International University
Due to the explosive growth of human activities in recent years, thousands of toxic and hazardous synthetic organic compounds produced for industrial, domestic and agricultural purpose have continued to pollute fresh water systems. Many of these pollutants are classified as persistent organic pollutants (POPs). When POPs are released into the environment, they remain unchanged for a long period. Due to their prolonged presence in the environment, many of these pollutants finally find their way in the food chain, with severe implications in the health and well-being of human. As such, it is imperative that these compounds be efficiently removed from environmental water through more efficient sewerage treatment processes and other reliable, yet inexpensive remediation techniques.
Among many classical processes used in removing pollutants from water, adsorption is one of the most effective removal techniques. A large number of carbonaceous adsorbents including activated carbon, carbon nanotube, biochar, graphene, calixarenes, poly(styrene-divinyl benzene), carboxen, fullerene, cation exchange resins, anion exchange resins and many others are used as adsorbents in sewerage treatment plants. These adsorbents offer a large variety of intermolecular interactions towards the analytes including µ-µ stacking interactions, cation-µ bonding interactions, electron donor-acceptor interactions, hydrophobic interactions, hydrogen bonding interaction, cation exchange, anion exchange, dipole-dipole interactions etc. Many of these adsorbents possess extremely high surface area and demonstrate strong tendency to form agglomeration. As such, when they are used in their pristine form, a large portion of their available surface area cannot be readily accessed by the analytes due to their agglomeration. As a result, the adsorption capacities of these adsorbents remain largely unexploited during their applications. The agglomeration of these unique particulate matters can be inhibited by encapsulated them into sol-gel silica network. Sol-gel chemistry provides a convenient and mild reaction pathway to create pure silica or organically modified silica 3-D network. Addition of adsorbent particles into the sol solution during sol-gel synthesis results in a sol-gel composite sorbent system with homogeneously trapped particulate matters. Due to the inherently porous and open architecture of sol-gel silica network, the encapsulated particulate matters maintain their high surface area as well as freely accessible interaction sites. As such, the synergistic combination of silica chemistry as well as the chemistry of particulate matters result in robust composite material systems capable of exerting intermolecular/ionic interactions towards a wide variety of analytes including polar, medium polar, nonpolar, ionic, and metal species and successfully trap them in the sol-gel composite sorbent matrices.
Analytical data obtained from a number of real-life applications of the sol-gel composite sorbents including endocrine disrupting chemicals (EDCs), Pharmaceuticals and personal care products (PPCPs), polycyclic aromatic hydrocarbon (PAHs) in environmental water will be presented showcasing their advantages, extraction characteristics, performance superiority, and analytical figures of merit.
The effect of dual frequency sonolytic irradiation on the production of hydroxyl radicals and efficiency of degradation of model dye compounds
Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, 33199 USA
Ultrasonic irradiation of aqueous media generates tiny air bubbles which undergo rapid compression-expansion cycles leading to a violent collapse and three main reaction zones: the interior of the gaseous cavitation bubbles, the interface of gas bubble-liquid solution and the bulk solution. Pyrolysis of water vapor inside the cavitation bubbles and near the inerface leading to OH and H radicals which can diffuse among the different reaction zones leading to the degradation of a polluants and toxins. Only ~ 10 % of OH radicals can by transferred to the bulk solution where the majority of target compounds often reside. The interface processes hydrophobic solvating properties while the bulk solution processes hydrophilic properties. Therefore, the partitioning of hydrophilic and hydrophobic pollutants and subsequent radical attack can be dramatically different within the reaction zones. In this work, two frequencies of ultrasound (20 kHz and 670 khz) were applied in order to investigate the degradation effectiveness when applying a second frequency to promote mixing among the different reaction zones. To assess the efficiency of dual frequency ultrasound, the power intensity per mL of each equipments were calculated with colorimetry at different amplitudes and power outputs. The results are evaluated according to the sonochemical efficiency calculated from the ratio of dye degradation percentage to ultrasonic intensity, which have shown the radical production decreasing with increasing frequency.
Copper Cycling in Sediments of Lakes Treated with Copper-Based Pesticides
Mohrah F. Albalawi and Melanie J. Beazley
University of Central Florida
Copper-based algaecides and herbicides are commonly used in aquatic systems to control problematic algae and weeds leading to concerns of copper accumulation at application sites. In spite of this accumulation, algaecides and herbicides are still routinely applied throughout the year and, therefore, create an environmental concern. Excessive amounts of copper are toxic to fish and other aquatic organisms as well as affect microbial metabolic activities in aquatic sediments. For this study, water and sediment were collected from two central Florida lakes that have had monthly treatments of copper-based pesticides for the past seven years. Control samples were collected at an untreated lake. Speciation experiments determined that copper was primarily associated with the organic fraction. Copper was also present in the adsorbed and precipitated fractions, confirming thermodynamic models of copper speciation. In contrast, control lake sediments contained lower total copper concentrations and did not exhibit changes in depth. The results of this study will help elucidate the fate of copper from pesticides in aquatic environmental systems.