Biodegradation of Dispersed Endicott Oil in Controlled Experiments

2014 ◽  
Vol 2014 (1) ◽  
pp. 1126-1140 ◽  
Author(s):  
Yves Robert Personna ◽  
Michel C. Boufadel ◽  
Shuangyi Zhang
Keyword(s):  
Brackish Water ◽  
Oil Spills ◽  
Aerobic Biodegradation ◽  
Initial Concentration ◽  
Dispersed Oil ◽  
Oil Biodegradation ◽  
Simultaneous Operations ◽  
Chemically Dispersed Oil ◽  
Seawater Samples ◽  
Total Oil

ABSTRACT We investigate aerobic biodegradation of dispersed Endicott oil in seawater at 15±0.5 °C in laboratory flasks. The objectives of the experiments were to (1) compare the biodegradability of chemically dispersed oil by Corexit 9500 with physically dispersed oil, and (2) determine whether the addition of nutrient affects the biodegradation rates of dispersed oil. The seawater samples (~ 6.5 g/L i.e. brackish water) were collected from Prince William Sound, Alaska. The biodegradation of Endicott oil was investigated for a period of 42 days under high nutrient (HN) (addition of 100 mg NO3-N/L and 10 mg PO4-P/L to background brackish water) and low nutrient (LN) (background brackish water) treatments. In the physically dispersed microcosms, oil biodegradation remained negligible for both HN and LN treatments. However, in the chemically dispersed oil microcosms, 24% and 14% of the total oil biodegraded in the HN (initial concentration= 0.304±0.095 g/L) and LN (initial concentration= 0.298±0.041 g/L) treatments within two weeks, respectively. These results demonstrated that the use of chemical dispersants coupled with nutrient addition can accelerate oil biodegradation. These findings can help develop better bioremediation strategies for addressing oil spills in the sea by focusing on simultaneous operations for rapid oil dispersion and stimulation of microbial growth through the availability of nutrients.

scholarly journals Development of an Algorithm for Chemically Dispersed Oil Spills

2020 ◽  
Vol 7 ◽  
Author(s):  
Merv F. Fingas ◽  
Kaan Yetilmezsoy ◽  
Majid Bahramian
Keyword(s):  
Wind Speed ◽  
Water Column ◽  
Oil Spills ◽  
Regression Equations ◽  
Oil Viscosity ◽  
Mixing Depth ◽  
Chemical Dispersion ◽  
Closed Form Solutions ◽  
Dispersed Oil ◽  
Chemically Dispersed Oil

An algorithm utilizing four basic processes was described for chemical oil spill dispersion. Initial dispersion was calculated using a modified Delvigne equation adjusted to chemical dispersion, then the dispersion was distributed over the mixing depth, as predicted by the wave height. Then the droplets rise to the surface according to Stokes’ law. Oil on the surface, from the rising oil and that undispersed, is re-dispersed. The droplets in the water column are subject to coalescence as governed by the Smoluchowski equation. A loss is invoked to account for the production of small droplets that rise slowly and are not re-integrated with the main surface slick. The droplets become less dispersible as time proceeds because of increased viscosity through weathering, and by increased droplet size by coalescence. These droplets rise faster as time progresses because of the increased size. Closed form solutions were provided to allow practical limits of dispersibility given inputs of oil viscosity and wind speed. Discrete solutions were given to calculate the amount of oil in the water column at specified points of time. Regression equations were provided to estimate oil in the water column at a given time with the wind speed and oil viscosity. The models indicated that the most important factor related to the amount of dispersion, was the mixing depth of the sea as predicted from wind speed. The second most important factor was the viscosity of the starting oil. The algorithm predicted the maximum viscosity that would be dispersed given wind conditions. Simplified prediction equations were created using regression.

DEVELOPMENT AND APPLICATION OF DTox: A QUANTITATIVE DATABASE OF THE TOXICITY OF DISPERSANTS AND CHEMICALLY DISPERSED OIL

2014 ◽  
Vol 2014 (1) ◽  
pp. 733-746 ◽  
Author(s):  
Adriana C. Bejarano ◽  
Valerie Chu ◽  
Jeff Dahlin ◽  
Jim Farr
Keyword(s):  
Oil Spill ◽  
Oil Spills ◽  
Biological Effects ◽  
Life Stage ◽  
Data Repository ◽  
Toxicity Data ◽  
Dispersed Oil ◽  
Chemically Dispersed Oil ◽  
Data Source ◽  
High Concentrations

ABSTRACT The Deepwater Horizon oil spill revived discussions on the use of dispersants as an oil spill countermeasure. One of the greatest concerns regarding the use of dispersants deals with potential exposure of water column organisms to high concentrations of oil. While toxicity data on dispersants and physically and chemically dispersed oil have been generated for decades under controlled laboratory conditions, the practical use of this information has been limited by the lack of a centralized data repository. As a result, the Dispersant and Chemically Dispersed Oil Toxicity Database (DTox) was created to address that shared need of unrestricted and rapid access to toxicity data. DTox is a quantitative database that gathers existing toxicity data through a careful review and compilation of data extracted from the peer-review and gray literature. Through a rigorously evaluation of the quality of each data source, this database contains pertinent information including species scientific name, life stage tested, dispersant name, exposure type, oil weathering stage, exposure duration, etc. More importantly, this database contains effects concentrations reported on measured or nominal basis. Within the database, each data source is assigned an applicability score based on their relevance to oil spills. Key criteria in the determination of source applicability include exposure type, reported effects concentrations, and reported analytical chemistry. Information in DTox has been further integrated into a user-friendly tool that allows for on-the-fly data searches and data plotting in the form of Species Sensitivity Distributions. To date, +400 papers have been evaluated for potential inclusion into the database, and data extracted from +170 sources. Despite inherent limitations, existing toxicity data are of great value to the oil spill scientific community. Although toxicity data will never be enough to answer all toxicity questions regarding the use of dispersants, this centralized data repository can help inform decisions on dispersant use and can help identify data needs and gaps. The ultimate goal of this tool is its contribution to a better understanding of the biological effects of dispersants and oil in the aquatic environment.

Ocean Experiments And Remotely Sensed Images of Chemically Dispersed Oil Spills

1983 ◽  
Vol GE-21 (1) ◽  
pp. 2-15 ◽  
Author(s):  
William F. Croswell ◽  
John C. Fedors ◽  
Frank E. Hoge ◽  
Robert N. Swift ◽  
Jaret C. Johnson
Keyword(s):  
Oil Spills ◽  
Remotely Sensed ◽  
Dispersed Oil ◽  
Chemically Dispersed Oil ◽  
Remotely Sensed Images

COMPARING CRUDE OIL TOXICITY UNDER STANDARD AND ENVIRONMENTALLY REALISTIC EXPOSURES

1995 ◽  
Vol 1995 (1) ◽  
pp. 1003-1004 ◽  
Author(s):  
Charles B. Pace ◽  
James R. Clark ◽  
Gail E. Bragin
Keyword(s):  
Crude Oil ◽  
Real World ◽  
Petroleum Hydrocarbons ◽  
Oil Spills ◽  
Aquatic Toxicity ◽  
Total Petroleum Hydrocarbons ◽  
Toxicity Tests ◽  
Continuous Exposure ◽  
Dispersed Oil ◽  
Chemically Dispersed Oil

ABSTRACT Standard aquatic toxicity tests do not address real-world, spiked exposure scenarios that occur during oil spills. We evaluated differences in toxicity of physically and chemically dispersed Kuwait crude oil to mysids (Mysidopsis bahia) under continuous and spiked (half-life of 2 hours) exposure conditions. The 96-hr LC50s for physically dispersed oil were 0.78 mg/L (continuous) and >2.9 mg/L (spiked), measured as total petroleum hydrocarbons (TPH). Values for chemically dispersed oil were 0.98 mg/L (continuous) and 17.7 mg/L (spiked) TPH. Continuous-exposure tests may overestimate the potential for toxic effects under real-world conditions by a factor of 18 or more.

EFFECTS OF OIL AND CHEMICALLY DISPERSED OIL IN SEDIMENTS ON CLAMS1

1985 ◽  
Vol 1985 (1) ◽  
pp. 349-353 ◽  
Author(s):  
Jack W. Anderson ◽  
Steven L. Kiesser ◽  
Dennis L. McQuerry ◽  
Gilbert W. Fellingham
Keyword(s):  
Free Amino ◽  
Field Experiments ◽  
Surface Sediments ◽  
Surface Layers ◽  
Dispersed Oil ◽  
Chemically Dispersed Oil ◽  
Protothaca Staminea ◽  
Total Oil ◽  
Prudhoe Bay ◽  
Lower Tolerance

ABSTRACT Several field experiments with natural sediments in the intertidal zone were conducted over a two-year period to compare the effects of Prudhoe Bay crude oil and this same oil dispersed with Corexit® 9527 (1 part Corexit to 10 parts oil). The clams used were Protothaca staminea and Macoma inquinata. Exposure periods ranged from one to six months. In a one-month exposure to about 2,000 parts per million (ppm) total oil in sediments, survival of P. staminea was two to three times greater than that of M. inquinata, and both species exhibited lower tolerance to oil alone in sediment than dispersed oil at the same concentration. However, uptake of naphthalenes and phenanthrenes by M. inquinata was greater from sediments mixed with dispersed oil than oil alone. Dispersed oil in this 30-day exposure also produced a decrease (compared to field controls) in the concentration of some of the free amino acids in the tissues of M. inquinata. Four- and six-month field exposures of small P. staminea to sediment containing oil or dispersed oil (about 2,000 ppm) reduced growth in both oil treatments (four-month exposure) or in just the chemically dispersed oil treatment (six-month exposure). In the latter experiment initial petroleum concentrations in the surface sediments (top 3 centimeters) were higher (about 3,000 ppm) for the dispersed oil than for oil alone. Surface layers in both conditions were free of contamination (down to 6 cm) after six months.

scholarly journals Estimating the Usefulness of Chemical Dispersant to Treat Surface Spills of Oil Sands Products

2018 ◽  
Vol 6 (4) ◽  
pp. 128 ◽  
Author(s):  
Thomas King ◽  
Brian Robinson ◽  
Scott Ryan ◽  
Kenneth Lee ◽  
Michel Boufadel ◽  
...  
Keyword(s):  
Oil Sands ◽  
Oil Spills ◽  
Breaking Waves ◽  
Oil Viscosity ◽  
Chemical Dispersant ◽  
Dispersed Oil ◽  
Initial Release ◽  
Order Of Magnitude ◽  
Chemically Dispersed Oil ◽  
The Impact

This study examines the use of chemical dispersant to treat an oil spill after the initial release. The natural and chemically enhanced dispersion of four oil products (dilbit, dilynbit, synbit and conventional crude) were investigated in a wave tank. Experiments were conducted in spring and summer to capture the impact of temperature, and the conditions in the tank were of breaking waves with a wave height of 0.4 m. The results showed that natural dispersion effectiveness (DE) was less than 10%. But the application of dispersant increased the DE by an order of magnitude with a statistically significant level (p < 0.05). Season (spring versus summer) had an effect on chemical DE of all oils, except for the conventional oil. Thus, the DE of dilbit products is highly dependent on the season/temperature. A model was fitted to the DE as a function of oil viscosity for the chemically dispersed oil, and the correlation was found to be very good. The model was then combined with a previous model compiled by the author predicting oil viscosity as a function of time, to produce a model that predicts the DE as function of time. Such a relation could be used for responders tackling oil spills.

A hazard assessment of chemically dispersed oil spills and seabirds

1987 ◽  
Vol 22 (2) ◽  
pp. 91-106 ◽  
Author(s):  
D.B. Peakall ◽  
P.G. Wells ◽  
D. Mackay
Keyword(s):  
Hazard Assessment ◽  
Oil Spills ◽  
Dispersed Oil ◽  
Chemically Dispersed Oil

Recent Studies on Fate and Degradation of Hydrocarbons Dispersed Subsea

2017 ◽  
Vol 2017 (1) ◽  
pp. 271-290
Author(s):  
Victoria Broje
Keyword(s):  
Oil Spill ◽  
Oil Spills ◽  
Health And Safety ◽  
Scientific Basis ◽  
American Petroleum Institute ◽  
Environmental Benefit ◽  
Current State ◽  
Dispersed Oil ◽  
Oil Biodegradation ◽  
State Of The Science

ABSTRACT The goal of applying dispersants as an oil spill response technique whether at the surface or subsea is to minimize surface oil impacts to people, wildlife, and shorelines and to facilitate rapid dilution and natural degradation of the dispersed oil in the water column. Thus, reliable estimates of the fate and degradation of oil, dispersed oil, and, for subsea releases, gas are key considerations when selecting response techniques. The American Petroleum Institute (API) has sponsored research on various aspects of subsea dispersant injection for over 4 years. Three of the most recent of those studies further advanced our understanding of the fate and biodegradation of hydrocarbons dispersed subsea and are discussed in this paper. An effort to evaluate the latest dispersed oil biodegradation studies and biodegradation modeling algorithms resulted in an overview of current state-of-the-science for characterizing biodegradation processes in far field oil spill models and recommendations on improving these modeling practices. Another project examined the current state-of-the-science on oil sedimentation processes including “marine snow” formation in the context of oil spills and dispersant use. It was conducted in order to better understand dynamics, fate, and environmental impacts of oil sedimentation from the perspective of Net Environmental Benefit Analysis, NEBA (aka Spill Impact Mitigation Assessment). The third study conducted numerical modeling to predict the fate of light hydrocarbons with and without subsea dispersant use and to estimate the changes in air quality near a well site. The goal of this effort was to evaluate whether subsea dispersant injection can reduce surface volatile hydrocarbon concentrations in the vicinity of well-control operations to protect responders’ health and safety. These and other API projects advanced our understanding of the scientific and environmental aspects of subsea dispersant use and provide a scientific basis for inclusion of this technique into contingency plans.

scholarly journals DISPERSION AND BIODEGRADATION OF OIL SPILLS ON WATER

1995 ◽  
Vol 1995 (1) ◽  
pp. 101-106 ◽  
Author(s):  
R. Varadaraj ◽  
M. L. Robbins ◽  
J. Bock ◽  
S. Pace ◽  
D. MacDonald
Keyword(s):  
Microbial Growth ◽  
Oil Spills ◽  
Interfacial Area ◽  
Positive Influence ◽  
Oil Degradation ◽  
Apparent Contradiction ◽  
Dispersed Oil ◽  
Oil Biodegradation ◽  
Designed Experiment ◽  
The Difference

ABSTRACT Published literature indicates that oil spill dispersion by chemical dispersants will enhance biodegradation because of the increase in interfacial area. However, some of the literature is contradictory concerning whether the use of surfactants will enhance or temporarily inhibit biodegradation, suggesting that more than one mechanism is at work. We set out to study the correlation between the area of dispersed oil droplets and the rate and extent of microbial oil degradation using sorbitan surfactants. We varied the surfactant blend hydrophile-lipophile balance (HLB) and treat level in a statistically designed experiment. Both dispersed area and percent oil degraded at a given time were shown to depend on surfactant HLB and treat level, but to different degrees. The difference was accounted for by demonstrating that percent oil degraded depended on both dispersed area and percent sorbitan in the dispersant treat. The quantitative finding that both dispersed area and surfactant chemistry control microbial growth and oil biodegradation explains the apparent contradiction that some good dispersants enhance, while others temporarily inhibit, degradation. Corexit 9500 dispersant was observed to have a positive influence on biodegradation of oil on water.

THE 1979 SOUTHERN CALIFORNIA DISPERSANT TREATED RESEARCH OIL SPILLS

1981 ◽  
Vol 1981 (1) ◽  
pp. 269-282 ◽  
Author(s):  
Clayton D. McAuliffe ◽  
Brian L. Steelman ◽  
William R. Leek ◽  
Daniel E. Fitzgerald ◽  
James P. Ray ◽  
...  
Keyword(s):  
Oil Spills ◽  
American Petroleum Institute ◽  
Low Molecular Weight ◽  
Long Beach ◽  
Volatile Hydrocarbons ◽  
Color Changes ◽  
Underwater Photography ◽  
Dispersed Oil ◽  
Total Oil ◽  
Prudhoe Bay

ABSTRACT Over a 2-day period in late September 1979, the American Petroleum Institute (API) discharged nine 10- or 20-barrel volumes of Alaskan Prudhoe Bay crude oil in a test area offshore of Long Beach, California. Two untreated slicks served as controls; three were sprayed with a self-mix dispersant from a DC–4 aircraft; three were sprayed with the same dispersant from a boat; and one was sprayed with a second dispersant from a boat. Movies and still photographs were taken from the air, and from under the aerially treated slicks. Over 900 water samples were collected from under the slicks. These samples were analyzed for total oil and for loss of low-molecular-weight hydrocarbons. Aerial and underwater photography showed marked color changes for the better dispersed slicks. Chemical analysis showed 45 to 80 percent of the oil was dispersed by aerial treatment. Treating the “lens” of thicker oil by boat dispersed 60 percent of the oil, while treating the entire slick uniformly dispersed from 5 to 10 percent. The two tested dispersants varied in their effectiveness, confirming prior laboratory tests. Under the best-dispersed slicks, the highest oil concentrations were 20 to 40 parts per million at 1 meter, observed 10 to 15 minutes after treatment. Other high oil concentrations were from 10 to 15 ppm at 1, 3, and 6 m; and 1 to 3 ppm at 9 meters, 1 hour after treatment; thereafter concentrations decreased. Dispersed oil very rapidly lost volatile hydrocarbons (C1 to C10). Less than 1 percent of the oil dispersed naturally under the untreated slicks.

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