Grantee Research Project Results
Chemical Degradation Pathways for the Natural Attenuation of Marine Biotoxins
EPA Grant Number: R831042Title: Chemical Degradation Pathways for the Natural Attenuation of Marine Biotoxins
Investigators: Ferry, John L. , Moeller, Peter M.
Institution: University of South Carolina at Columbia , Center for Coastal Environmental Health Biomolecular Research (CCEHBR)
EPA Project Officer: Packard, Benjamin H
Project Period: September 1, 2003 through August 31, 2006
Project Amount: $404,403
RFA: Ecology and Oceanography of Harmful Algal Blooms (2002) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems , Water
Objective:
During harmful algal bloom events, toxins are dispersed into the food web through planktonic, detrital, or solution pathways. We hypothesize that this transfer is occurring against a continuous backdrop of chemical reactions that can act to attenuate the chemical signature of the bloom in the water column, including direct and indirect photooxidation, adsorption onto suspended solids, and hydrolysis. Photoactive suspended solids may also engage in photocatalyzed oxidation or reduction of the toxin.
Approach:
We will test this hypothesis by exposing solutions of several purified toxins to a matrix of different possible oxidizing conditions, including illumination in the presence of photosensitizers (Fe oxides, colloidal and crystalline; NO3-; varying levels of dissolved organic matter) under several different water quality conditions (varying salinity, pH, total carbonate, and suspended clays or colloidal silica). Dissolved organic matter (DOM) may also provide a hyrdophobic microenvironment for toxins to partition into, so we will measure the partitioning constant (Koc) for these toxins into dissolved organic matter as well, with particular emphasis placed on measuring how DOM and Koc vary with water quality and affect adsorption on suspended solids.
Expected Results:
The overarching goal of the proposal is explore the fundamental fate and transport processes that govern the abiotic processing of marine toxins. The specific objectives of the study are to a) build a library of multivariate models for describing the half-life of a given toxin as a function of light intensity, suspended solids, and water quality during a bloom, b) to identify degradation products, for further toxicity evaluation or use as chemical markers of abiotic degradation in the field, and c) build databases of Koc with respect to water quality. We believe this knowledge will be critical for predicting the impact of a harmful bloom event, and also that it will yield valuable insight into the possible ecological function of marine toxins based on new understanding of their persistence in the environment.
Publications and Presentations:
Publications have been submitted on this project: View all 15 publications for this projectJournal Articles:
Journal Articles have been submitted on this project: View all 6 journal articles for this projectSupplemental Keywords:
photochemistry, marine, radical, kinetics, RFA, Scientific Discipline, Water, Ecosystem Protection/Environmental Exposure & Risk, Oceanography, algal blooms, Environmental Monitoring, dissolved organic matter, marine ecosystem, bloom dynamics, food web, marine biotoxins, chemical degradation, nutrient kinetics, natural attenuation, water quality, photocatalytic oxidation, algal bloom detectionProgress and Final Reports:
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.