COMPARATIVE TOXICITY OF OIL, DISPERSANT, AND DISPERSED OIL TO TEXAS MARINE SPECIES

ABSTRACT Dispersants are one class of chemical response agents currently approved for use on offshore oil spills. However, questions persist regarding potential environmental risks of nearshore dispersant applications. To address these questions, the relative toxicity of weathered crude oil, dispersant, and weathered crude oil plus dispersant were compared. This study included one luminescent marine bacteria (Vibrio fisheri), two marine vertebrate (Cyprinodon variegatus and Menidia beryllina), and one invertebrate test species (Mysidopsis bahia). Both the vertebrate and invertebrate species were tested under spiked (short episodic) exposure regimes and 96-hour continuous exposure regimes using protocols developed by the Chemical Response to Oil Spills: Ecological Effects Research Forum (CROSERF) and U.S. Environmental Protection Agency (EPA), respectively. Toxicity to the marine bacteria was evaluated after a 15-minute exposure using the Microbics Microtox® system. Results showed no significant variance between the relative toxicity of solutions prepared with weathered crude oil only and weathered crude oil plus dispersant when evaluated with the vertebrate and invertebrate test species. However, oil only solutions were shown to be significantly more toxic to Vibrio fisheri than oil plus dispersant solutions. Data also indicated that constant exposures were significantly more toxic than declining exposures, which is generally consistent with time weighted exposure response evaluations. Microtox® data was comparable to both vertebrate and invertebrate test results suggesting that the method is suitable for toxicity field screening.

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COOPERATIVE STUDIES ON THE TOXICITY OF DISPERSANTS AND DISPERSED OIL TO MARINE ORGANISMS: A 3-YEAR FLORIDA STUDY

International Oil Spill Conference Proceedings ◽

10.7901/2169-3358-2001-2-1237 ◽

2001 ◽

Vol 2001 (2) ◽

pp. 1237-1241 ◽

Cited By ~ 7

Author(s):

Dana L. Wetzel ◽

Edward S. Van Fleet

Keyword(s):

Crude Oil ◽

Standard Test ◽

Sciaenops Ocellatus ◽

Crude Oils ◽

Continuous Exposure ◽

Test Species ◽

Dispersed Oil ◽

Test Organisms ◽

Flow Through ◽

Exposure Conditions

ABSTRACT The present study was conducted to assess the toxicity of the water-accommodated fraction (WAF) and the chemically enhanced WAF (CE-WAF) of selected crude oils for both weathered and fresh oil. Test organisms included two standard test species, Mysidopsis bahia and Menidia beryllina, and a commercially important Florida marine fish, Sciaenops ocellatus. Tests ascertaining LC50 values were conducted under continuous exposure and spiked (declining exposure using flow-through toxicity chambers) conditions using Venezuelan Crude Oil (VCO), Prudhoe Bay Crude Oil (PBCO), and COREXIT® 9500 dispersant on the above species. Data suggest that the dispersant is less toxic than the WAF and CE-WAF of the tested crude oils. The toxicity of the CE-WAF of fresh VCO is similar to that of other oils under continuous exposure conditions, but may be slightly more toxic to some species under spiked exposure conditions. The CE-WAF of fresh VCO appears to be less toxic than the corresponding WAF for M. bahia, M. beryllina, and S. ocellatus. Fresh VCO appears to be much more toxic to M. bahia and M. beryllina than weathered VCO in spiked exposure tests for both the WAF and CE-WAF. The WAF of PBCO is apparently less toxic to the test organisms than the corresponding WAF of fresh VCO. The LC50 values of M. bahia with CE-WAF fractions of both fresh VCO and PBCO are similar, while the same PBCO CE-WAF fraction is less toxic for M. beryllina than fresh VCO CE-WAF. The toxicity of oils and dispersants were lowest in the spiked exposure weathered oil tests, which may be most representative of an oil spill under natural environmental conditions.

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COMPARING CRUDE OIL TOXICITY UNDER STANDARD AND ENVIRONMENTALLY REALISTIC EXPOSURES

International Oil Spill Conference Proceedings ◽

10.7901/2169-3358-1995-1-1003 ◽

1995 ◽

Vol 1995 (1) ◽

pp. 1003-1004 ◽

Cited By ~ 8

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.

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Toxicity of Dispersants and Dispersed Oil To An Alaskan Marine Organism

International Oil Spill Conference Proceedings ◽

10.7901/2169-3358-1999-1-1035 ◽

1999 ◽

Vol 1999 (1) ◽

pp. 1035-1038 ◽

Cited By ~ 2

Author(s):

Sara L. Rhoton ◽

Robert A. Perkins ◽

Zachary D. Richter ◽

Christina Behr-Andres ◽

Jon E. Lindstrom ◽

...

Keyword(s):

Crude Oil ◽

Oil Spills ◽

Marine Organism ◽

Oil Dispersant ◽

Crab Larvae ◽

Dispersed Oil ◽

Tanner Crab ◽

Exposure Testing ◽

The University ◽

Chionoecetes Bairdi

ABSTRACT The University of Alaska Fairbanks (UAF) conducted toxicity assays on Alaskan tanner crab larvae (Chionoecetes bairdi) using the oil dispersant Corexit 9500, Alaska North Slope (ANS) crude oil, and dispersed ANS crude oil. These tests were conducted in Seward, Alaska using filtered saltwater at ambient temperature (6°C) and salinity (35%c). Similar toxicity assays were conducted at UAF on the reference species Mysidopsis bahia and Menidia beryllina under standard testing conditions (25°C and 20%c salinity). The methods used for these tests were developed by the Chemical Response to Oil Spills: Ecological Research Forum (CROSERF) and involve both continuous and spiked (declining concentration) exposure testing regimes. Toxicity data, expressed as EC50, were calculated using the defined response of “Affected,” as the typical response was decreased phototatic response; death as an endpoint was not often observed. The larvae were evaluated and placed into the following categories: Alive, Affected, Mortally Affected, and Dead. Results suggest that the tanner crab larvae are generally more resistant (EC50 = 355 mg/L) than M. beryllina (LC50 = 205 mg/L) and less resistant than M. bahia (LC50 = 622 mg/L) to dispersant solutions under spiked exposure.

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Dispersant effectiveness on oil spills – impact of salinity

ICES Journal of Marine Science ◽

10.1016/j.icesjms.2006.04.019 ◽

2006 ◽

Vol 63 (8) ◽

pp. 1418-1430 ◽

Cited By ~ 39

Author(s):

Subhashini Chandrasekar ◽

George A. Sorial ◽

James W. Weaver

Keyword(s):

Experimental Data ◽

Crude Oil ◽

Oil Spills ◽

Refined Oil ◽

Light Crude Oil ◽

Mixing Energy ◽

Oil Dispersant ◽

Dispersant Effectiveness ◽

Almost All ◽

The Impact

Abstract When a dispersant is applied to an oil slick, its effectiveness in dispersing the spilled oil depends on factors such as oil properties, wave-mixing energy, temperature, and salinity of the water. Estuaries represent water with varying salinity, so in this study, three salinity values in the range 10–34 psu were investigated, representing potential salinity concentrations found in typical estuaries. Three oils were chosen to represent light refined oil, light crude oil, and medium crude oil. Each was tested at three weathering levels to represent maximum, medium, and zero weathering. Two dispersants were chosen for evaluation. A modified trypsinizing flask termed a baffled flask was used to conduct the experimental runs. A full factorial experiment was conducted for each oil. The interactions between the effects of salinity and three environmental factors, temperature, oil weathering, and mixing energy, on dispersion effectiveness were investigated. Each experiment was replicated four times in order to evaluate the accuracy of the test. Statistical analyses of the experimental data were performed for each of the three oils independently for each dispersant treatment (two dispersants and oil controls). A linear regression model representing the main factors (salinity, temperature, oil weathering, flask speed) and second-order interactions among the factors was fitted to the experimental data. Salinity played an important role in determining the significance of temperature and mixing energy on dispersant effectiveness for almost all the oil–dispersant combinations. The impact of salinity at different weathering was only significant for light crude oil with dispersant A.

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CLEANUP AND EFFECTS OF CRUDE OIL AND FUEL OIL SPILLS IN OSITO CANYON: A COMPARISON

International Oil Spill Conference Proceedings ◽

10.7901/2169-3358-1987-1-483 ◽

1987 ◽

Vol 1987 (1) ◽

pp. 483-487

Author(s):

Jack A. Kemerer ◽

Terrence McGuigan ◽

Douglas Campbell

Keyword(s):

Crude Oil ◽

Oil Spill ◽

Environmental Protection Agency ◽

Technical Assistance ◽

Oil Spills ◽

Fuel Oil ◽

Government Officials ◽

Financial Responsibility ◽

Environmentally Sensitive ◽

Crude Oil Spill

ABSTRACT In July 1981, a crude oil spill from a pipeline break occurred in Osito Canyon near Castaic, California. In April 1984, a tank truck accident on Interstate Route 5 resulted in a fuel oil spill into a tributary canyon to Osito Canyon. Although the spills occurred at virtually the same location, the amounts spilled, the extent of the canyons contaminated, and the cleanup methods used produced different recovery results. The spillers assumed financial responsibility for cleanup actions and complied with the concerns and recommendations of government officials. The Environmental Protection Agency served as the on-scene coordinator, while the U. S. Forest Service and the U. S. Coast Guard's Pacific Strike Team provided on-site monitors and technical assistance. Impact from the spills appeared to be negligible on the chaparral type vegetation and sparse concentration of wildlife in the area. Effects from the spills were not lasting, and no environmentally sensitive downstream areas were affected.

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ORGANISM EXPOSURE TO VOLATILE/SOLUBLE HYDROCARBONS FROM CRUDE OIL SPILLS—A FIELD AND LABORATORY COMPARISON

International Oil Spill Conference Proceedings ◽

10.7901/2169-3358-1987-1-275 ◽

1987 ◽

Vol 1987 (1) ◽

pp. 275-288 ◽

Cited By ~ 13

Author(s):

Clayton D. McAuliffe

Keyword(s):

Crude Oil ◽

Water Column ◽

Oil Spills ◽

Open Water ◽

Marine Species ◽

High Water ◽

Water Soluble ◽

Field Exposure ◽

Near Surface ◽

Total Oil

ABSTRACT The acute toxicities of the water soluble fraction of crude oils or the aqueous solution of individual hydrocarbons were compared with the field exposure concentrations to dissolved hydrocarbons under crude oil slicks and emulsion plumes from chemically dispersed slicks. The exposures were related by expressing LC50 values for differing times and varying concentrations as a product (mean concentration × time = ppm-hours). Field exposures to soluble hydrocarbons under oil slicks on open water or in plumes of efficiently dispersed slicks are very low (from 150 to 1 million times lower) compared with exposures to cause half mortality for more than 50 marine species. This is so because oil slicks are thin, generally with average thickness between 0.1 and 0.01 mm. A high water-to-oil ratio limits the concentration of total oil to 10 to 100 ppm in the top meter of water, and 1 to 10 in 10 m. The soluble and volatile hydrocarbons quickly evaporate to the atmosphere from the slick or from near-surface waters. The field exposure of organisms in the water column is low initially and is transitory. Thus, oil spills and the chemical dispersion of slicks are unlikely to have measurable adverse effects on larval, juvenile, or adult marine organisms in the water column.

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SENSITIVITY OF 39 ALASKAN MARINE SPECIES TO COOK INLET CRUDE OIL AND NO. 2 FUEL OIL

International Oil Spill Conference Proceedings ◽

10.7901/2169-3358-1979-1-549 ◽

1979 ◽

Vol 1979 (1) ◽

pp. 549-554 ◽

Cited By ~ 10

Author(s):

Stanley D. Rice ◽

Adam Moles ◽

Tamara L. Taylor ◽

John F. Karinen

Keyword(s):

Crude Oil ◽

Aromatic Hydrocarbons ◽

Oil Spills ◽

Soluble Fraction ◽

Marine Species ◽

Water Soluble ◽

Fuel Oil ◽

Cook Inlet ◽

Test Conditions ◽

Intertidal Environments

ABSTRACT The sensitivities of 39 subarctic Alaskan species of marine fish and invertebrates to water-soluble fractions of Cook Inlet crude oil and No. 2 fuel oil were determined. This is the largest group of animals ever tested under similar test conditions with the same petroleum oils and analytical methods. Organisms bioassayed represent several habitats, six phyla, and 39 species including fish (9), arthropods (9), molluscs (13), echinoderms (4), annelids (2), and nemer-teans (2). Sensitivities were determined by 96-hour static bioassays. Concentrations of selected aromatic hydrocarbons were determined by gas chromatography; concentrations of paraffins were determined by infrared spectrophotometry. Although sensitivity generally increased from lower invertebrates to higher invertebrates, and from higher invertebrates to fish, sensitivity was better correlated to habitat. Pelagic fish and shrimp were the most sensitive animals to Cook Inlet crude oil with 96-h median tolerance limits (TLm's) from 1–3 mg/l total aromatic hydrocarbons. Benthic animals, including fish, crabs, and scallops were moderately tolerant (TLm's to Cook Inlet crude oil of 3–8 mg/l total aromatic hydrocarbons). Intertidal animals, including fish, crabs, and starfish, and many molluscs, were the most tolerant forms to water-soluble fraction of petroleum (TLm's greater than 8–12 mg/l of total aromatic hydrocarbons). Most of the intertidal animals were not killed by static oil exposures. No. 2 fuel oil was more toxic to most species than Cook Inlet crude oil. Sensitive pelagic animals are not necessarily more vulnerable to oil spills than tolerant intertidal forms — oil may damage intertidal environments more easily and adverse effects may persist longer than in damaged pelagic environments.

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TOXICITY OF DISPERSANT, OIL, AND DISPERSED OIL TO TWO MARINE ORGANISMS

International Oil Spill Conference Proceedings ◽

10.7901/2169-3358-1997-1-1010 ◽

1997 ◽

Vol 1997 (1) ◽

pp. 1010-1011 ◽

Cited By ~ 2

Author(s):

Ismail Gulec ◽

Douglas A. Holdway

Keyword(s):

Crude Oil ◽

Sodium Dodecyl Sulphate ◽

Zinc Sulphate ◽

Sodium Dodecyl ◽

Marine Organisms ◽

Test Species ◽

Oil Dispersant ◽

Dispersed Oil ◽

Marine Sand

ABSTRACT Acute lethal bioassays using semistatic conditions were conducted to assess the toxicity of crude oil, dispersant, and dispersed oil using the amphipod Allorchestes compressa as a test species. Sublethal bioassays (suppression of burying behavior over 24 hours of exposure) were conducted for these toxicants using the marine sand snail Polinices conicus. Both lethal and sublethal bioassays were also carried out for two reference toxicants: sodium dodecyl sulphate (SDS) and zinc sulphate.

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