scholarly journals SUBMERSIBLE OPTICAL SENSORS EXPOSED TO CHEMICALLY-DISPERSED CRUDE OIL: WAVE TANK SIMULATIONS FOR IMPROVED OIL SPILL MONITORING

2014 ◽  
Vol 2014 (1) ◽  
pp. 300156
Author(s):  
R.N. Conmy ◽  
P.G. Coble ◽  
J. Farr ◽  
A.M. Wood ◽  
R. Parsons ◽  
...  
Keyword(s):  
Crude Oil ◽  
Oil Spill ◽  
Optical Sensors ◽  
Performance Testing ◽  
Breaking Waves ◽  
Sensor Data ◽  
Total Petroleum Hydrocarbons ◽  
Wave Tank ◽  
Vicarious Calibration ◽  
Dispersed Oil

In situ fluorometers were deployed during the Deepwater Horizon (DWH) Gulf of Mexico oil spill to provide critical measurements for tracking the subsea oil plume. In the wake of the spill, uncertainties regarding instrument specifications, capabilities and reliability necessitated performance testing of sensors (commonly used during spill response) exposed to simulated, dispersed oil plumes. Moreover, concerns on the applicability of laboratory calibrations (at high concentrations and insufficient mixing energies) to field conditions and on sensor reliability to detect dispersed oil persist. To address these uncertainties the performance of select commercially-available sensors (from Chelsea Technologies Group, Satlantic, Turner Designs, WetLabs Inc) was evaluated using a wave tank facility at the Bedford Institute of Oceanography in Halifax, Nova Scotia. Breaking waves were generated within the tank to simulate mixing energies and achieve dispersant effectiveness observed in the field. Presented here are the results of the sensors exposed to chemically-dispersed MC252 crude oil using Corexit 9500, DOR=1:20. Stepwise additions of dispersed oil (0.3 – 12 ppm) to the tank were used to establish linearity. Model 1 linear least squares regressions were calculated and applied to sensor data during validation experiments to simulate dilution of an oil plume. Dynamic ranges of the sensors, exposed to fresh and artificially weathered crude oil, were determined. Sensors were standardized against known oil volumes and measured Total Petroleum Hydrocarbons (TPH) and Benzene-Toluene-Ethylbenzene-Xylene (BTEX) values – both collected during spills, providing oil estimates during dilution experiments. Results were validated against particle size data (Sequoia LISST). All sensors estimated oil concentrations down to 300 ppb oil, refuting previous reports. Low percent differences and absolute errors between chemistry and sensor results were metrics to evaluate performance. Discussed will be the application of this vicarious calibration approach as a means to calibrate the DWH fine-scale fluorescence data into oil concentrations. This allows for filling in coarse-scale field chemistry data, improved assessment of DWH spill measurements mined from the NOAA NODC, and understanding the fate and transport of the DWH oil plume.

Submersible Optical Sensors Exposed to Chemically Dispersed Crude Oil: Wave Tank Simulations for Improved Oil Spill Monitoring

2014 ◽  
Vol 48 (3) ◽  
pp. 1803-1810 ◽  
Author(s):  
Robyn N. Conmy ◽  
Paula G. Coble ◽  
James Farr ◽  
A. Michelle Wood ◽  
Kenneth Lee ◽  
...  
Keyword(s):  
Crude Oil ◽  
Oil Spill ◽  
Optical Sensors ◽  
Wave Tank

scholarly journals Oil spill detection in the east of Sri Lanka with Sentinel-1 SAR

2020 ◽  
Vol 211 ◽  
pp. 02013
Author(s):  
W. Kamal M. Mahindapala
Keyword(s):  
Sri Lanka ◽  
Crude Oil ◽  
Oil Spill ◽  
Optical Sensors ◽  
Oil Spills ◽  
Oil Pollution ◽  
Signal Transmission ◽  
The Indian Ocean ◽  
Sea Area ◽  
Oil Tanker

In September 2020, two major fires broke out in a large crude oil tanker in Sri Lanka’s maritime zones. An island with a vast sea area in the Indian Ocean, Sri Lanka, is prone to vessel sourced pollution. Crude oil can have a damaging impact on the environment, and therefore tracking the spill in the water is essential. Spaceborne sensors support monitoring oil pollution; however, optical sensors need clear skies for observation. The detection of pollution caused by vessels; in Sri Lanka’s maritime zones has previously been investigated by the author. This study examines the data collected by the Sentinel-1 satellite, whose sensing corresponds to the oil spill event, manually and using algorithms to detect the presence of oil spills. Two detected oil spill areas were measured to be 0.6 km and 1.4 km long. Further, in this study, the SAR sensor’s vertical signal transmission and reception mode produced acceptable results in detecting the spills and the vessel. Sentinel-1 SAR data is essential, in this case, to detect the presence of the oil spills and the vessels.

Oil plume simulations: Tracking oil droplet size distribution and fluorescence within high-pressure release jets

2017 ◽  
Vol 2017 (1) ◽  
pp. 1230-1250
Author(s):  
R.N. Conmy ◽  
B. Robinson ◽  
T. King ◽  
M. Boufadel ◽  
S. Ryan ◽  
...  
Keyword(s):  
Water Temperature ◽  
Size Distribution ◽  
Droplet Size ◽  
Oil Spill ◽  
Droplet Diameter ◽  
Performance Testing ◽  
Droplet Size Distribution ◽  
Optical Measurements ◽  
Total Petroleum Hydrocarbons

ABSTRACT Optical measurements have been used during oil spill response for more than three decades to determine oil presence in slicks and plumes. Oil surveillance approaches range from simple (human eyeball) to the sophisticated (sensors on AUVs, aircraft, satellites). In situ fluorometers and particle size analyzers were deployed during the Deepwater Horizon (DWH) Gulf of Mexico oil spill to track shallow and deep subsea plumes. Uncertainties regarding instrument specifications and capabilities during DWH necessitated performance testing of sensors exposed to simulated, dispersed oil plumes. Seventy-two wave tank experiments were conducted at the Bedford Institute of Oceanography. Simulated were oil releases with varying parameters such as oil release rate, oil temperature (reservoir temp ~ 80 °C), water temperature (<8 °C and >15 °C), oil type, dispersant type (Corexit 9500 and Finasol OSR52) and dispersant to oil ratio (DOR). Plumes of Alaskan North Slope Crude (ANS), South Louisiana Crude (SLC) and IFO-120 oils were tracked using in situ fluorescence, droplet size distribution (DSD), total petroleum hydrocarbons (TPH) and benzene-toluene-ethylbenzene-xylene (BTEX). For the lighter SLC, bimodal droplet size with mean diameter < 70 μm was achieved for 1:20 and 1:100 DOR, regardless of water temperature. Similarly, the medium ANS crude exhibited mean droplet diameter <70 μm, but was bimodal only for the 1:20 treatment. Bimodal distribution was not achieved with the heavy IFO, but droplet < 70 μm were observed for 1:20 warm waters, indicating poor dispersibility of the high viscosity oil even for jet releases. Results offer valuable information on the behavior and dispersibility of oils over a range of viscosity, DOR and environmental conditions. Findings have implications for fate and transport models, where DSD, chemistry and fluorescence are all impacted by release variables. This research was supported by the Bureau of Safety and Environmental Enforcement.

OIL DROPLET SIZE DISTRIBUTION AS A FUNCTION OF ENERGY DISSIPATION RATE IN AN EXPERIMENTAL WAVE TANK

2008 ◽  
Vol 2008 (1) ◽  
pp. 621-626 ◽  
Author(s):  
Zhengkai Li ◽  
Kenneth Lee ◽  
Thomas King ◽  
Michel C. Boufadel ◽  
Albert D. Venosa
Keyword(s):  
Energy Dissipation ◽  
Size Distribution ◽  
Dissipation Rate ◽  
Droplet Size Distribution ◽  
Breaking Waves ◽  
Energy Dissipation Rate ◽  
Wave Tank ◽  
Chemical Dispersant ◽  
Dispersed Oil ◽  
Dispersant Effectiveness

ABSTRACT The U.S. National Research Council (NRC) Committee on Understanding Oil Spill Dispersants: Efficacy and Effects (2005) identified two factors that require further investigation in chemical oil dispersant efficacy studies: 1) quantification of mixing energy at sea as energy dissipation rate and 2) dispersed particle size distribution. To fully evaluate the significance of these factors, a wave tank facility was designed and constructed to conduct controlled oil dispersion studies. A factorial experimental design was used to study the dispersant effectiveness as a function of energy dissipation rate for two oils and two dispersants under three different wave conditions, namely regular non-breaking waves, spilling breakers, and plunging breakers. The oils tested were weathered MESA and fresh ANS crude. The dispersants tested were Corexit 9500 and SPC 1000 plus water for no-dispersant control. The wave tank surface energy dissipatation rates of the three waves were determined to be 0.005, 0.1, and 1 m2/s3, respectively. The dispersed oil concentrations and droplet size distribution, measured by in-situ laser diffraction, were compared to quantify the chemical dispersant effectiveness as a function of energy dissipation rate. The results indicate that high energy dissipation rate of breaking waves enhanced chemical dispersant effectiveness by significantly increasing dispersed oil concentration and reducing droplet sizes in the water column (p <0.05). The presence of dispersants and breaking waves stimulated the oil dispersion kinetics. The findings of this research are expected to provide guidance to disperant application on oil spill responses.

scholarly journals Tropical Oil Pollution Investigations in Coastal Systems [TROPICS]: A 32-year Review of Response and Recovery

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
D. Abigail Renegar ◽  
Paul Schuler ◽  
Nicholas Turner ◽  
Richard Dodge ◽  
Anthony Knap ◽  
...  
Keyword(s):  
Crude Oil ◽  
Oil Spill ◽  
Field Experiments ◽  
Oil Pollution ◽  
Environmental Benefit ◽  
Coastal Systems ◽  
Dispersed Oil ◽  
Trade Offs ◽  
Nearshore Environments ◽  
Comparative Risk

ABSTRACT In 1984, the Tropical Oil Pollution Investigations in Coastal Systems (TROPICS) experiment began in Bahia Almirante on the Caribbean coast of Panama. This study sought to compare the impacts of a severe, but realistic spill of untreated crude oil versus chemically treated (dispersed) crude oil on tropical marine reef, sea-grass, and mangrove ecosystems. The aim of the study was to identify and evaluate the environmental trade-offs of dispersant use in tropical marine and subtidal systems. As a result of continuing research at the site, the study became one of the most comprehensive field experiments examining the long-term impacts of oil and dispersed oil exposures in nearshore tropical communities. Consequently, TROPICS has been the foundational and seminal field study which served as the historical antecedent for Net Environmental Benefit Analysis (NEBA), as well as the basis for follow-on Spill Impact Mitigation Analysis (SIMA) and Comparative Risk Analysis (CRA) for oil spill planning, preparation, and response. From the initial experiment in 1984, through three decades of study and data collection visits, the coral reef, seagrass, and mangrove communities have exhibited significantly different damage and recovery regimes, depending on whether the sites were exposed to non-treated crude oil or dispersed crude oil. While this study does not definitively determine whether or not dispersants should be applied in tropical nearshore environments, it is illustrative of the environmental and ecosystem trade-offs between surface oil impacts to the shoreline, compared to water column exposure from chemically dispersed oil. This paper provides an overview of the results and observations reported in numerous previous TROPICS publications, as a progression of damage and recovery over time. With this perspective, planners and responders can use this study to predict what damages/recoveries may be expected from an oil spill incident in this environment. The results of the TROPICS experiment are examined within the context of this recent parallel research from the perspective of ongoing implications for oil spill preparedness and response.

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.

A COMPARISON OF THE EFFECTS OF TAPIS CRUDE OIL AND DISPERSED CRUDE OIL ON SUBTIDAL ZOSTERA CAPRICORNI

2008 ◽  
Vol 2008 (1) ◽  
pp. 859-864
Author(s):  
K. G. Wilson ◽  
P. J. Ralph
Keyword(s):  
Crude Oil ◽  
Substantial Reduction ◽  
Pulse Amplitude ◽  
Exposure Period ◽  
Water Soluble ◽  
Total Petroleum Hydrocarbons ◽  
Environmental Benefit ◽  
Pigment Analysis ◽  
Dispersed Oil ◽  
Zostera Capricorni

ABSTRACT Oil spill mitigation managers need to know the effects of chemical dispersants on subtidal seagrass in order to determine the least net environmental impact of their actions. The decision-making process for chemical dispersant use in Australia, known as Net Environmental Benefit Analysis, is compromised in near shore areas due to a lack of information on dispersed oil impacts on subtidal seagrasses. This study aimed to determine the toxic effects of crude oil, dispersed and non-dispersed, on subtidal seagrass and to quantify the exposure amount. Zostera capricorni plants were exposed to a range of concentrations of different oil and dispersant combinations in the field. ?hotosynthetic health was measured using Pulse Amplitude Modulated (PAM) fluorometry and chlorophyll pigment analysis. Oil concentration was calculated in relative oil units using Ultraviolet Fluoresence (UVF) spectrophotometry. Limited photo synthetic impact was detected in Z. capricorni exposed to the water soluble fraction of the non-dispersed Tapis crude oil treatments. No significant photo synthetic impact was evident in the dispersed Tapis crude oil treatment even though the Total Petroleum Hydrocarbon (TPH) concentration in these treatments was higher than in the non-dispersed Tapis crude oil treatments. Plants from both treatments recovered following replenishment from the surrounding seawater. A substantial reduction of the total petroleum hydrocarbons within the mesoscosms over the 10 hour exposure period was evident and would likely suggest a rapid loss of the toxic mixture to the sediments rather than assimilation by the seagrass.

EFFECTS OF A DISPERSED OIL SPILL ON BIOFOULING COMMUNITIES

1997 ◽  
Vol 1997 (1) ◽  
pp. 1034-1035 ◽  
Author(s):  
José La Schiazza ◽  
Jorge Rodriguez-Grau ◽  
Freddy Losada
Keyword(s):  
Crude Oil ◽  
Oil Spill ◽  
Control Groups ◽  
High Recovery ◽  
Biological Impact ◽  
Dispersed Oil ◽  
Recovery Capacity ◽  
Acute Disturbance ◽  
And Control ◽  
Crude Oil Spill

ABSTRACT Biofouling communities (groups of encrusting organisms) growing on Plexiglas plates were selected as bioindicators to evaluate the effects of a simulated dispersed crude oil spill. Results showed significant changes in the number of taxa, abundance, and percentage of substrate cover between treated and control groups; however, these effects represent a relatively low biological impact produced by the dispersed oil. The overall conclusion is that biofouling has a high recovery capacity despite an actual acute disturbance, since many biofouling organisms showed a significant resistance to the effects of dispersed crude oil.

Continuing Long-Term Studies of the Tropics Panama Oil and Dispersed Oil Spill Sites

2003 ◽  
Vol 2003 (1) ◽  
pp. 259-267 ◽  
Author(s):  
Greg A. Ward ◽  
Bart Baca ◽  
Wendy Cyriacks ◽  
Richard E. Dodge ◽  
Anthony Knap
Keyword(s):  
Crude Oil ◽  
Oil Spill ◽  
Tree Mortality ◽  
Oil Pollution ◽  
Bocas Del Toro ◽  
The Past ◽  
Dispersed Oil ◽  
Present Information ◽  
The Tropics

ABSTRACT The TROPICS (Tropical Oil Pollution Investigations in Coastal Systems) oil spill experiment was conducted on the Caribbean coast of Panama, near Bocas del Toro. In November 1984, crude and dispersed crude oil were released in two separate boom-enclosed areas representative of intertidal mangrove and subtidal seagrass/coral ecosystems. The present information is based on site visits over the past two years, including 2002. Following the degradation of oil over the past 18 years, sheen identified from the spilled oil in 1994 is still visible in non-dispersed Oil Site sediments. In mangroves, previously denuded areas exposed to crude oil are currently occupied by new seedlings and saplings, which are growing rapidly but with morphological prop-root deformations. Tree mortality occurred in both the Dispersed Oil and Reference Sites, but was non-localized and appeared as natural mortality in aged trees. Recent data have revealed an invasion of seagrass beds by finger coral at the Oil Site. Since treatment, percent coverage of corals at this site has grown from a pretreatment value of 33.5% in March 1984 to 67.5% in June 2001.

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