Kenneth Lee

Bio: Kenneth Lee is an academic researcher from Dartmouth College. The author has contributed to research in topics: Biodegradation & Petroleum. The author has an hindex of 7, co-authored 17 publications receiving 288 citations. Previous affiliations of Kenneth Lee include Government of Canada & Southern Illinois University Edwardsville.

Nutrient and oxygen concentrations within the sediments of an Alaskan beach polluted with the Exxon Valdez oil spill

Abstract: Measurements of the background concentrations of nutrients, dissolved oxygen (DO), and salinity were obtained from a beach that has oil from the Exxon Valdez oil spill in 1989 Two transects were set across the beach, one passed through an oil patch while the other transect was clean Three pits were dug in each transect, and they ranged in depth from 09 to 15 m The DO was around 10 mg L -1 at oiled pits and larger than5mgL -1 at clean pits The average nutrient concentrations in the beach were 039 mg-N L -1 and 0020 mg-P L -1 Both concentrationsarelowerthanoptimalvaluesforoilbiodegradation (2 to 10 mg-N L -1 and 040 to 20 mg-P L -1 ), which suggests that they are both limiting factors for biodegradation The lowest nitrate and DO values were found in the oiled pits, leading to the conclusion that microbial oil consumption was probably occurring under anoxic conditions and was associated to denitrification We present evidence that the oxygen level may be a major factor limiting oil biodegradation in the beaches

A Review on the Factors Affecting the Deposition, Retention, and Biodegradation of Oil Stranded on Beaches and Guidelines for Designing Laboratory Experiments

Abstract: The distribution and persistence of oil within the matrix of a beach depends on the oil and beach properties, the presence of fines in the water column, and beach hydrodynamics and biochemistry. In this review, we attempted to provide an assessment of the journey of oil from offshore oil spills until it deposits within beaches. In particular, we addressed the disparity of spatial scales between microscopic processes, such as the formation of oil particle aggregates and oil biodegradation, and large-scale forcings, such as the tide. While aerobic biodegradation can remove more than 80% of the oil mass from the environment, its rate depends on the pore water concentration of oxygen and nutrients, both of them vary across the beach and with time. For this reason, we discussed in details the methods used for measuring water properties in situ and ex situ. We also noted that existing first-order decay models for oil biodegradation are expedient, but might not capture impacts of water chemistry on oil biodegradation. We found that there is a need to treat the beach–nearshore system as one unit rather than two separate entities. Scaling down large-scale hydrodynamics requires a coarser porous medium in the laboratory. Unfortunately, this implies that microscopic-scale processes cannot be reproduced in such a setup, and one needs a separate system for simulating small-scale processes. Our findings of large spatio-temporal variability in pore-water properties suggest that major advancements in addressing oil spills on beaches require holistic approaches that combine hydrodynamics with biochemistry and oil chemistry.

Field Trials of in-situ Oil Spill Countermeasures in Ice-Infested Waters

Abstract: An oil spill response technique in ice-infested waters based on the application of fine minerals in a slurry with mixing by propeller-wash to promote the formation of oilmineral aggregates (OMA) has been proposed. This process promotes the physical dispersion of mineral-fine stabilized oil droplets into the water column that support higher rates of oil degradation by natural bacteria. To validate the operational effectiveness of this technique a controlled oil spill experiment was conducted from a Canadian Coast Guard ice-breaker in the St. Lawrence Estuary (offshore of Matane, Quebec, Canada). Following the release of the test crude oil and the application of experimental treatments, time-series changes in oil concentrations were monitored to quantify dispersion effectiveness. Field samples were also recovered for laboratory microcosm studies on the biodegradation of petroleum hydrocarbons by monitoring CO2 production and the depletion of specific hydrocarbon components. Detailed chemical analysis (GC/MS with hopane normalization) from these studies showed that more than 60% of the total petroleum hydrocarbon, 75-88% of total alkanes, and 55-65% total PAHs, were degraded after 56 days of incubation at 0.5 o C. The alkylated PAH was degraded to a greater extent following the addition of mineral fines. This technique offers several operational advantages as a spill countermeasure for use under Arctic conditions such as reduced numbers of personnel required for its application, no need for waste disposal sites, and cost effectiveness.

Oil Biodegradation and Bioremediation: A Tale of the Two Worst Spills in U.S. History

Abstract: Oil biodegradation and bioremediation: A tale of the two worst spills in U. S. history. Ronald M. Atlas, University of Louisville, Louisville KY 40292 Terry C. Hazen, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 Biography Ronald Atlas is Professor of Biology at the University of Louisville. He has over 40 years experience studying the role of microorganisms in oil biodegradation and helped pioneer the field of bioremediation. He has worked extensively on the bioremediation the Exxon Valdez spill. Terry Hazen is DOE BER distinguished scientist in the Earth Sciences Division at Lawrence Berkeley National Laboratory. He has studied oil, chlorinated solvent, and metal and radionuclide bioremediation for more then 30 years. He has been extensively studying the microbial degradation of the BP Deepwater Horizon Spill in the Gulf of Mexico. Abstract The devastating environmental impacts of the Exxon Valdez spill in 1989 and its media notoriety made it a frequent comparison to the BP Deepwater Horizon spill in the popular press in 2010, even though the nature of the two spills and the environments impacted were vastly different. Fortunately, unlike higher organisms that are adversely impacted by oil spills, microorganisms are able to consume petroleum hydrocarbons. These oil degrading indigenous microorganisms played a significant role in reducing the overall environmental impact of both the Exxon Valdez and BP Deepwater Horizon (MC252) oil spills. Introduction to Biodegradation of Petroleum Hydrocarbons Petroleum hydrocarbons in crude oils, such as those released into marine ecosystems by the Exxon Valdez and BP Deepwater Horizon spills, are natural products derived from aquatic algae laid down between 180 and 85 million years ago. Crude oils, composed mostly of diverse aliphatic and aromatic hydrocarbons, regularly escape into the environment from underground reservoirs. Because petroleum hydrocarbons occur naturally in all marine environments there has been time for numerous diverse microorganisms to evolve the capability of utilizing hydrocarbons as sources of carbon and energy for growth. Oil-degrading microorganisms are ubiquitous, but may only be a small proportion of the pre-spill microbial community. Bacteria, archaea, and fungi each have hundreds of species that can degrade petroleum. Most petroleum hydrocarbons are biodegradable under aerobic conditions; though a few compounds found in crude oils, e.g. resins, hopanes, polar molecules, and asphaltenes, have practically imperceptible biodegradation rates. Lighter crudes, such as the oil released from the BP Deepwater Horizon spill, contain a higher proportion of simpler lower molecular weight hydrocarbons that are more readily biodegraded than heavy crudes, such as the oil released from the Exxon Valdez. The polycyclic aromatic hydrocarbons (PAH) are a minor constituent of crude oils; however, they are among the most toxic to plants and animals. Bacteria can convert PAHs completely to biomass, CO 2 , and H 2 O, but they usually require the initial insertion of O 2 via dioxygenase enzymes. Anaerobic degradation of petroleum hydrocarbons can also occur albeit at a much slower rates. Petroleum hydrocarbons can be biodegraded at temperatures below freezing to more than 80°C. Microorganisms require elements other than carbon for

Oil weathering after the Deepwater Horizon disaster led to the formation of oxygenated residues.

Abstract: Following the Deepwater Horizon disaster, the effect of weathering on surface slicks, oil-soaked sands, and oil-covered rocks and boulders was studied for 18 months. With time, oxygen content increased in the hydrocarbon residues. Furthermore, a weathering-dependent increase of an operationally defined oxygenated fraction relative to the saturated and aromatic fractions was observed. This oxygenated fraction made up >50% of the mass of weathered samples, had an average carbon oxidation state of −1.0, and an average molecular formula of (C5H7O)n. These oxygenated hydrocarbon residues were devoid of natural radiocarbon, confirming a fossil source and excluding contributions from recent photosynthate. The incorporation of oxygen into the oil’s hydrocarbons, which we refer to as oxyhydrocarbons, was confirmed from the detection of hydroxyl and carbonyl functional groups and the identification of long chain (C10–C32) carboxylic acids as well as alcohols. On the basis of the diagnostic ratios of alkanes and pol...

Oil spill problems and sustainable response strategies through new technologies

Abstract: Crude oil and petroleum products are widespread water and soil pollutants resulting from marine and terrestrial spillages. International statistics of oil spill sizes for all incidents indicate that the majority of oil spills are small (less than 7 tonnes). The major accidents that happen in the oil industry contribute only a small fraction of the total oil which enters the environment. However, the nature of accidental releases is that they highly pollute small areas and have the potential to devastate the biota locally. There are several routes by which oil can get back to humans from accidental spills, e.g. through accumulation in fish and shellfish, through consumption of contaminated groundwater. Although advances have been made in the prevention of accidents, this does not apply in all countries, and by the random nature of oil spill events, total prevention is not feasible. Therefore, considerable world-wide effort has gone into strategies for minimising accidental spills and the design of new remedial technologies. This paper summarizes new knowledge as well as research and technology gaps essential for developing appropriate decision-making tools in actual spill scenarios. Since oil exploration is being driven into deeper waters and more remote, fragile environments, the risk of future accidents becomes much higher. The innovative safety and accident prevention approaches summarized in this paper are currently important for a range of stakeholders, including the oil industry, the scientific community and the public. Ultimately an integrated approach to prevention and remediation that accelerates an early warning protocol in the event of a spill would get the most appropriate technology selected and implemented as early as possible – the first few hours after a spill are crucial to the outcome of the remedial effort. A particular focus is made on bioremediation as environmentally harmless, cost-effective and relatively inexpensive technology. Greater penetration into the remedial technologies market depends on the harmonization of environment legislation and the application of modern laboratory techniques, e.g. ecogenomics, to improve the predictability of bioremediation.

The weathering of oil after the Deepwater Horizon oil spill: insights from the chemical composition of the oil from the sea surface, salt marshes and sediments

Abstract: The oil released during the Deepwater Horizon (DWH) oil spill may have both short- and long-time impacts on the northern Gulf of Mexico ecosystems. An understanding of how the composition and concentration of the oil are altered by weathering, including chemical, physical and biological processes, is needed to evaluate the oil toxicity and impact on the ecosystem in the northern Gulf of Mexico. This study examined petroleum hydrocarbons in oil mousse collected from the sea surface and salt marshes, and in oil deposited in sediments adjacent to the wellhead after the DWH oil spill. Oil mousses were collected at two stations (OSS and CT, located 130 and 85 km away from the wellhead, respectively) in May 2010, and two sediment samples from stations SG and SC, within 6 km of the wellhead, in May 2011. We also collected oil mousse from salt marshes at Marsh Point (MP), Mississippi, 186 km away from the wellhead in July 2010. In these samples, n-alkanes, polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, BTEX (collective name of benzene, toluene, ethylbenzene and p-, m-, and o-xylenes), C3-benzenes and trace metals were measured to examine how the oil was altered chemically. The chemical analysis indicates that the oil mousses underwent different degrees of weathering with the pattern of OSS < CT < MP. This pattern is consistent with the projected oil mousse movement from the accident site to salt marshes. Also, the contents of trace metals Al, V, Cr, Fe, Mn, Ni, Co, Cu, As and Pb in the oil mousse generally increased along the way to the salt marshes, indicating that these trace metals were perhaps aggregated into the oil mousse during the transport. Petroleum hydrocarbon data reveal that the oil deposited in sediments underwent only light to moderate degradation one year after the DWH oil spill, as supported by the presence of short-chained n-alkanes (C10–C 15), BTEX and C 3-benzenes. The weathering of oil in sediment may result from biological degradation and dissolution, evidenced by the preferential loss of mid-chained n-alkanes C16–C 27, lower ratios of n-C 17/Pr and n-C 18/Ph , and preferential loss of PAHs relative to alkylated PAHs.