2004 Progress Report: Chemical Degradation Pathways for the Natural Attenuation of Marine BiotoxinsEPA Grant Number: R831042
Title: 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 Period Covered by this Report: September 1, 2003 through August 31, 2004
Project Amount: $404,403
RFA: Ecology and Oceanography of Harmful Algal Blooms (2002) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems , Ecosystems , Water
The overall objective of this research project is to explore the fundamental fate and transport processes that govern the abiotic processing of marine toxins. The specific objectives are to: (1) 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; (2) identify degradation products for further toxicity evaluation or use as chemical markers of abiotic degradation in the field; and (3) build databases of Koc with respect to water quality. We believe that this knowledge will be critical for predicting the impact of a harmful bloom event and that it will yield valuable insight into the possible ecological function of marine toxins based on a new understanding of their persistence in the environment.
A high throughput approach to combinatorial photochemical fate estimation has been developed (including reactor design and testing). Analysis of the photostability of the natural background has been completed, with particular attention payed to the role of dissolved organic matter, dissolved Fe, NO3-, and salinity. It has been observed that under conditions that approximate the concentration range of these parameters in the natural environment (in seawater and estuaries), photobleaching of dissolved organic carbon is independent of [NO3-]o or [Fe(III)]o. Photobleaching of the natural background carbon is most pronounced at 350 nm and occurs within 17-35 hours of illumination (750 W/m2, as a function of initial conditions). Analytical methods for domoate analysis in seawater and in suspensions have been adopted to local equipment capabilities. Domoate is observed to photodegrade much more rapidly than dissolved organic carbon, with a tentative half-life of less than 5 hours under all conditions tested. A method for in situ derivatization of simple carboxylic acids to the corresponding fluorinated ethyl amides has been developed to aid in byproduct determination.
The investigators did not report any future activities.