marine coastal environments; stable isotopes; oil spill; Deepwater Horizon; photooxidation; biodegradation; organic pollutants; natural halogenated compounds
Aeppli Christoph, Tysklind Mats, Holmstrand Henry, Gustafsson Orjan (2013), Use of Cl and C Isotopic Fractionation to Identify Degradation and Sources of Polychlorinated Phenols: Mechanistic Study and Field Application, in
ENVIRONMENTAL SCIENCE & TECHNOLOGY, 47(2), 790-797.
Wiegert Charline, Aeppli Christoph, Knowles Tim, Holmstrand Henry, Evershed Richard, Pancost Richard D., Machackova Jirina, Gustafsson Orjan (2012), Dual Carbon-Chlorine Stable Isotope Investigation of Sources and Fate of Chlorinated Ethenes in Contaminated Groundwater, in
ENVIRONMENTAL SCIENCE & TECHNOLOGY, 46(20), 10918-10925.
Aeppli Christoph, Carmichael Catherine A., Nelson Robert K., Lemkau Karin L., Graham William M., Redmond Molly C., Valentine David L., Reddy Christopher M. (2012), Oil Weathering after the Deepwater Horizon Disaster Led to the Formation of Oxygenated Residues, in
ENVIRONMENTAL SCIENCE & TECHNOLOGY, 46(16), 8799-8807.
Wiegert C., Mandalakis M., Knowles T., Polymenakou P.N., Aeppli C., Machackova J., Holmstrand H., Evershed R.P., Pancost R.D., Gustafsson O., Carbon and Chlorine Isotope Fractionation During Microbial Degradation of Tetra- and Trichloroethene, in
Environmental Science and Technology, doi:10.102.
Aeppli C., Bastviken D., Andersson P., Gustafsson Ö., Chlorine isotope effects and composition of naturally produced organochlorines from chloroperoxidases, flavin-dependent halogenases, and in forest soil, in
Environmental Science and Technology, doi:10.102.
Natural halogenated compounds (NHCs) are prevalent in marine environment, and a variety of phenolic NHCs have been detected in seawater, sediments, and along the marine food chain. Since many NHCs have also industrially produced analogs, apportion natural and anthropogenic sources is important for global emission budgets, which are often lacking data of NHC production. Beside formation, also NHC degradation is of importance, since the same reaction pathways that nature uses for dehalogenating NHCs are also used for biodegrading a variety of anthropogenic halogenated pollutants. The aim of this project is to assess marine phenolic NHC formation and degradation using compound-specific isotope analysis. While the use of stable halogen and carbon isotopes are very powerful to assess the formation and degradation of NHCs, radiocarbon analysis (C-14) allows for apportion natural and industrial sources of halogenated compounds. The objectives of the proposed research are to characterize kinetic isotope effects associated with phenolic NHC production as well as degradation in well-defined laboratory systems. This information will then be used for isotope-based identification of NHCs formation pathways in marine algae and worms, as well as for assessment of NHC dynamics in marine costal and open ocean systems.Novel continuous-flow analytical methods for analyzing chlorine, bromine, and carbon stable isotopes (based on GC/MS, GC/ICP/MS, and GC/C/IRMS) will be used for analysis of the target phenolic NHCs. Radiocarbon analysis will be preformed for source apportionment for selected analytes using accelerated mass spectrometry (AMS). Experiments will be conducted with pure enzymes as well as with crude extracts of algal and worm enzymes, and NHCs will be analyzed from marine biota, seawater and sediments.The proposed project is expected to allow isotope-based apportionment of natural and anthropogenic halogenated compounds in marine systems of different spatial scales (benthic biota, costal environment, and open ocean). Furthermore, it will provide insights on a molecular level in halogenation mechanisms of marine organisms, as well as in NHC dechlorination pathways.