ORCID Profile
0000-0002-7814-2071
Current Organisation
Woods Hole Oceanographic Institution
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Publisher: Proceedings of the National Academy of Sciences
Date: 18-07-2012
Abstract: Quantitative information regarding the endmember composition of the gas and oil that flowed from the Macondo well during the Deepwater Horizon oil spill is essential for determining the oil flow rate, total oil volume released, and trajectories and fates of hydrocarbon components in the marine environment. Using isobaric gas-tight s lers, we collected discrete s les directly above the Macondo well on June 21, 2010, and analyzed the gas and oil. We found that the fluids flowing from the Macondo well had a gas-to-oil ratio of 1,600 standard cubic feet per petroleum barrel. Based on the measured endmember gas-to-oil ratio and the Federally estimated net liquid oil release of 4.1 million barrels, the total amount of C 1 -C 5 hydrocarbons released to the water column was 1.7 × 10 11 g. The endmember gas and oil compositions then enabled us to study the fractionation of petroleum hydrocarbons in discrete water s les collected in June 2010 within a southwest trending hydrocarbon-enriched plume of neutrally buoyant water at a water depth of 1,100 m. The most abundant petroleum hydrocarbons larger than C 1 -C 5 were benzene, toluene, ethylbenzene, and total xylenes at concentrations up to 78 μg L -1 . Comparison of the endmember gas and oil composition with the composition of water column s les showed that the plume was preferentially enriched with water-soluble components, indicating that aqueous dissolution played a major role in plume formation, whereas the fates of relatively insoluble petroleum components were initially controlled by other processes.
Publisher: American Chemical Society (ACS)
Date: 24-10-2017
Abstract: Humans have interacted with fire for thousands of years, yet the utilization of fossil fuels marked the beginning of a new era. Ubiquitous in the environment, pyrogenic carbon (PyC) arises from incomplete combustion of biomass and fossil fuels, forming a continuum of condensed aromatic structures. Here, we develop and evaluate
Publisher: American Chemical Society (ACS)
Date: 04-03-2019
Abstract: Industrial-scale dumping of organic waste to the deep ocean was once common practice, leaving a legacy of chemical pollution for which a paucity of information exists. Using a nested approach with autonomous and remotely operated underwater vehicles, a dumpsite offshore California was surveyed and s led. Discarded waste containers littered the site and structured the suboxic benthic environment. Dichlorodiphenyltrichloroethane (DDT) was reportedly dumped in the area, and sediment analysis revealed substantial variability in concentrations of p, p-DDT and its analogs, with a peak concentration of 257 μg g
Publisher: Elsevier BV
Date: 08-2011
DOI: 10.1016/J.CHROMA.2011.06.021
Abstract: 18α(H)-, 18β(H)-oleanane and lupane are angiosperm-derived biomarkers that are used as age indicators for the Late Cretaceous onwards when the first proliferation of angiosperms occurred. In addition, the 18α(H)-/18β(H)-oleanane ratio is employed as a thermal maturity parameter of crude oil. However, evidence has shown that accurate quantification of these compounds has been impeded by inadequate chromatographic separation by traditional one-dimensional gas chromatography. In this study, we present the separation of 18α(H)-, 18β(H)-oleanane and lupane with comprehensive two-dimensional gas chromatography (GC×GC). Furthermore, it was observed that 18β(H)-oleanane elutes earlier than 18α(H)-oleanane in second dimension (polarity) which we attribute to steric hindrance effects. Two GC conditions have been developed in order to achieve baseline separation of the triterpenoids of interest in complex mixtures such as sediment extracts and crude oils.
Publisher: IEEE
Date: 07-2011
Publisher: Proceedings of the National Academy of Sciences
Date: 22-04-2019
Publisher: American Chemical Society (ACS)
Date: 21-07-0001
Publisher: Springer Science and Business Media LLC
Date: 25-04-2010
DOI: 10.1038/NGEO848
Publisher: CSIRO Publishing
Date: 2011
DOI: 10.1071/EN10090
Abstract: Environmental contextBrominated organic compounds of both natural and anthropogenic origin are commonly found in the environment. Bromine has two stable isotopes and the isotopic composition of brominated compounds may vary depending on production pathways and degradation processes. These variations are a result of isotope fractionation effects, when heavy isotopes react slower than lighter isotopes. We apply compound-specific bromine isotope analysis to industrial brominated organic compounds, and one naturally produced analogue, to test the feasibility of the technique to investigate the source and environmental fate of these compounds. AbstractThe stable bromine isotopic composition (δ81Br) was determined for six industrially synthesised brominated organic compounds (BOCs) and one natural BOC by gas-chromatography multi-collector inductively coupled plasma mass spectrometry (GC-mcICP-MS). The δ81Br compositions of brominated benzenes, phenols (both natural and industrial), anisoles, and naphthalenes were constrained with the standard differential measurement approach using as reference a monobromobenzene s le with an independently determined δ81Br value (–0.39‰ v. Standard Mean Ocean Bromide, SMOB). The δ81Br values for the industrial BOCs ranged from –4.3 to –0.4‰. The average δ81Br value for the natural compound (2,4-dibromophenol) was 0.2 ± 1.6‰ (1 s.d.), and for the identical industrial compound (2,4-dibromophenol) –1.1 ± 0.9‰ (1 s.d.), with a statistically significant difference of ~1.4 (P 0.05). The δ81Br of four out of six industrial compounds was found to be significantly different from that of the natural s le. These novel results establish the bromine isotopic variability among the industrially produced BOCs in relation to a natural s le.
Publisher: Proceedings of the National Academy of Sciences
Date: 12-10-2015
Abstract: Organic compounds found in drinking water aquifers above the Marcellus Shale and other shale plays could reflect natural geologic transport processes or contamination from anthropogenic activities, including enhanced natural gas production. Using analyses of organic compounds coupled with inorganic geochemical fingerprinting, estimates of groundwater residence time, and geospatial analyses of shale gas wells and disclosed safety violations, we determined that the dominant source of organic compounds to shallow aquifers was consistent with surface spills of disclosed chemical additives. There was no evidence of association with deeper brines or long-range migration of these compounds to the shallow aquifers. Encouragingly, drinking water sources affected by disclosed surface spills could be targeted for treatment and monitoring to protect public health.
Publisher: ACM
Date: 08-11-2010
Publisher: American Chemical Society (ACS)
Date: 29-06-2022
Publisher: American Association for the Advancement of Science (AAAS)
Date: 08-10-2010
Abstract: The Deepwater Horizon oil spill in the Gulf of Mexico was one of the largest oil spills on record. Its setting at the bottom of the sea floor posed an unanticipated risk as substantial amounts of hydrocarbons leaked into the deepwater column. Three separate cruises identified and s led deep underwater hydrocarbon plumes that existed in May and June, 2010—before the well head was ultimately sealed. Camilli et al. (p. 201 published online 19 August) used an automated underwater vehicle to assess the dimensions of a stabilized, diffuse underwater plume of oil that was 22 miles long and estimated the daily quantity of oil released from the well, based on the concentration and dimensions of the plume. Hazen et al. (p. 204 published online 26 August) also observed an underwater plume at the same depth and found that hydrocarbon-degrading bacteria were enriched in the plume and were breaking down some parts of the oil. Finally, Valentine et al. (p. 208 published online 16 September) found that natural gas, including propane and ethane, were also present in hydrocarbon plumes. These gases were broken down quickly by bacteria, but primed the system for biodegradation of larger hydrocarbons, including those comprising the leaking crude oil. Differences were observed in dissolved oxygen levels in the plumes (a proxy for bacterial respiration), which may reflect differences in the location of s ling or the aging of the plumes.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2012
DOI: 10.1109/TLT.2011.36
Publisher: Elsevier BV
Date: 07-2008
DOI: 10.1016/J.ENVPOL.2007.10.008
Abstract: In September 1969, the Florida barge spilled 700,000 L of No. 2 fuel oil into the salt marsh sediments of Wild Harbor, MA. Today a substantial amount, approximately 100 kg, of moderately degraded petroleum remains within the sediment and along eroding creek banks. The ribbed mussels, Geukensia demissa, which inhabit the salt marsh creek bank, are exposed to the spilled oil. Examination of short-term exposure was done with transplantation of G. demissa from a control site, Great Sippewissett marsh, into Wild Harbor. We also examined the effects of long-term exposure with transplantation of mussels from Wild Harbor into Great Sippewissett. Both the short- and long-term exposure transplants exhibited slower growth rates, shorter mean shell lengths, lower condition indices, and decreased filtration rates. The results add new knowledge about long-term consequences of spilled oil, a dimension that should be included when assessing oil-impacted areas and developing management plans designed to restore, rehabilitate, or replace impacted areas.
Location: United States of America
Location: United States of America
No related grants have been discovered for Christopher Reddy.