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

2001 ◽  
Vol 2001 (2) ◽  
pp. 1237-1241 ◽  
Author(s):  
Dana L. Wetzel ◽  
Edward S. Van Fleet

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.

2001 ◽  
Vol 2001 (2) ◽  
pp. 1249-1255 ◽  
Author(s):  
James R. Clark ◽  
Gail E. Bragin ◽  
Eric J. Febbo ◽  
Daniel J. Letinski

ABSTRACT As part of efforts to develop standardized testing protocols under the Chemical Response to Oil Spills Environmental Research Forum (CROSERF) and apply the results to real-world scenarios, three types of oils and two dispersants were tested in both continuous and short-term spiked exposures using the early life-stages of several marine organisms. Test species included embryo-larval stages of Pacific oyster (Crassostrea gigas), two marine mysids (Holmesimysis costata and Mysidopsis bahia), and two marine fishes (turbot, Scophthalmus maximus and inland silverside, Menidia beryllina). Oils were physically dispersed in seawater by vortex mixing in a flask and chemically dispersed using the same approach with COREXIT® 9527 or COREXIT® 9500 applied in a 10:1 oil-to-dispersant ratio to generate maximum exposure concentrations. Continuous exposure tests followed standard testing protocols for 96-hour or 48-hour duration, according to demands of the test species. Spiked exposures reflect continuous dilution of water column concentrations (half-life ∼107 minutes), as observed in the field when oil is dispersed into open waters. Results are reported as the acute LC50s. Tests oils included fresh and weathered Kuwait crude, fresh Forties crude, and a Medium Fuel Oil (MFO) mix. Exposure concentrations for oil tests were quantified using gas chromatography and expressed as the sum of the C10 to C36 components, or TPH(resoived). Dispersant exposure concentrations were verified by UV spectrophotometric analysis. Not all species were tested with each oil and dispersant. For dispersants tested individually, constant exposure LC50s ranged from 3 to 75 mg/L, with oyster the most sensitive and turbot the least sensitive species. Spiked exposure LC50s ranged from 14 to >1055 mg/L among all test species. Dispersants were up to 36 times less toxic under spiked exposure conditions compared to similar treatments under constant exposure conditions. For oils, LC50s based on TPH(resolved) are similar for both the physically and chemically dispersed oil, demonstrating that dispersant did not increase the toxicity of oils based on measured exposures. Under constant exposure conditions, test species are very similar in sensitivity to the oils, with most LC50s around 0.5 ppm TPH(resolyed). Spiked exposures were 4 to 100 fold less toxic to these test organisms. The more environmentally realistic spiked exposures demonstrate that standard, continuous exposure test data overestimate the potential toxicity of dispersed oil. When laboratory toxicity data are used as part of a dispersant approval process for spill response, the decision should take into account whether exposure durations and sensitivity of test species are representative of conditions in the spill area.


2001 ◽  
Vol 2001 (2) ◽  
pp. 935-940 ◽  
Author(s):  
William R. Gala ◽  
Gary A. Rausina ◽  
Michael J. Ammann ◽  
Paul Krause

ABSTRACT Aquatic toxicity information is critical to provide scientifically defensible estimates of ecological impact and natural resource injury to aquatic organisms resulting from a petroleum spill. For most crude oils, the availability of aquatic toxicity information is a significant data gap. As part of Chevron's oil-specific properties summary sheet project, a series of marine fish (silversides, top smelt) and invertebrate (mysid shrimp) acute toxicity tests on five crude oils with extensive chemical analysis (e.g., VPH C6–C9, CROSERF VOCs, EPH C10–C32, PAHs) of exposure concentrations have been performed. Acute toxicity studies were conducted under standard test guidelines. ASTM D 6081 procedures were used to prepare individual water extracts, also called water-accommodated fractions (WAFs), of each test concentration to which the test organisms were exposed. WAF preparation and testing was done in tightly closed containers with minimal headspace to reduce volatilization and maintain stable exposure levels of dissolved hydrocarbons as much as possible. Also, WAFs were replenished daily with fresh test solution. Since toxicity results are expressed as the mean exposure concentration of a particular subset of the petroleum compounds in the WAF that resulted in 50% lethality in the test species, the LC50 values in μg/L will vary depending on which subset is used to describe the effect of the oil on the aquatic organisms. Additionally, since the aquatic organisms are exposed to a mixture of hydrocarbons in the WAF, LC50 values expressed as one subset's concentration are not independent of the presence of other petroleum constituent types. The results indicate that generally invertebrates (i.e., mysid) are more sensitive than fish. LC50s expressed as total polycyclic hydrocarbons (PAHs) showed the least variability—96-hour LC50s for total PAHs ranged from 19–36 μg/L and 30–128 μg/L for mysid and fish, respectively.


1995 ◽  
Vol 1995 (1) ◽  
pp. 1003-1004 ◽  
Author(s):  
Charles B. Pace ◽  
James R. Clark ◽  
Gail E. Bragin

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.


1973 ◽  
Vol 1973 (1) ◽  
pp. 703-714 ◽  
Author(s):  
P. Kauss ◽  
T. C. Hutchinson ◽  
C. Soto ◽  
J. Hellebust ◽  
M. Griffiths

ABSTRACT Field and laboratory experiments have been conducted to determine the toxicity of crude oil to freshwater algae. In the field, experiments were continued for a two year period and changes in the abundance and species composition of phytoplankton tabulated. Species were found to differ markedly in their response to an oil spill—varying from considerable suppression of growth to stimulation. In the laboratory, the effects of aqueous extracts of seven crude oils on a selected test species, Chlorella vulgaris, were determined. Marked differences in toxicity, as indicated by reduced growth, were found to exist between oils. Work with oil extracts of different ages suggests that the short-term toxicity of oils is due to the rapid loss of volatile compounds. Differences in the toxicity of selected aromatic components of crude oils—benzene, toluene, o-xylene and naphthalene—were observed and are believed to relate to an increase in methylation. Aqueous crude oil and naphthalene depressed the 14C-NaHC03 uptake (i.e. photosynthesis) of Chlamydomonas angulosa. 14C-naphthalene was rapidly taken up by Chlamydomonas cells. However, release of this compound was much slower, and, in unwashed cells, seemingly dependent upon cell division. Possible mechanisms of crude oil toxicity are discussed.


2005 ◽  
Vol 2005 (1) ◽  
pp. 247-252 ◽  
Author(s):  
Afag Abbasova ◽  
Khabiba Bagirova ◽  
Gary Campbell ◽  
James Clark ◽  
Ronnie Gallagher ◽  
...  

ABSTRACT Open marine water (salinity 30–35°/00) is the environment where dispersants are used most frequently in oil spill response. In the Azerbaijan sector of the Caspian Sea, offshore oil and gas reserves are being developed in areas where salinity ranges from 10 to 12 °loo. Because salinity can affect dispersant efficacy and toxicity, the effectiveness and aquatic toxicity of six commercially available dispersants were tested using Azerbaijan crude oil, Caspian species and 12°/oo seawater. Effectiveness for the dispersants tested with Chirag crude oil and Caspian seawater ranged from 72% to 86%, using USEPA's baffled flask method. Dispersant toxicities were in the ranges: diatom (Chaetoceros tenuissimus) 72 hr EC50 (effective concentrations inhibiting growth rate by 50%) 18 to > 100 mg/l; copepod (Calanipeda aquae dulcis) 48 hr LC50 (effective concentration for immobilizing 50% test organisms) 12 to 49 mg/l; amphipod (Pontogammarus maeoticus) 48 hr LC50 (concentration lethal to 50% test organisms) 50 to > 100 mg/l. For dispersant use, the key toxicity concern is that of dispersed oil, not dispersant. Aquatic toxicity was determined for water—accommodated fractions (WAFs) of Chirag crude in Caspian seawater. Toxicity results for the WAFs were: diatom 72 hr EC50 > 10,000 mg/l nominal; copepod 48 hr LC50 3.9 mg/l; amphipod 48 hr LC50 >15 mg/l. Chirag crude was mixed with dispersant at 20:1 oil: dispersant ratio and resulting WAFs were tested for toxicity. Results were: diatom 72 hr EC50 < 18 to 208 mg/l nominal; copepod 48 hr LC50 2.1 to 37 mg/l; amphipod 48 hr LC50 20 to 89 mg/l. Dispersant and dispersed oil toxicity for Caspian species are similar to published toxicity data for marine species tested at typical ocean salinity. Prolonged exposure (24 to 96hrs.) to constant concentrations of dispersant or dispersed oil used in laboratory tests may overestimate potential field toxicity, where dilution and mixing can decrease concentrations to low ppm's within hours of application. Dispersant use decisions for any Caspian Sea oil spills will focus on net environmental benefits of moving oil into the water column where it can be quickly diluted compared to potentially greater impacts from oil reaching nearshore environments.


2001 ◽  
Vol 2001 (2) ◽  
pp. 1243-1248 ◽  
Author(s):  
Chris Fuller ◽  
James S. Bonner

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.


1997 ◽  
Vol 1997 (1) ◽  
pp. 1010-1011 ◽  
Author(s):  
Ismail Gulec ◽  
Douglas A. Holdway

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.


2018 ◽  
Vol 5 (1) ◽  
pp. 43-54
Author(s):  
Suresh Aluvihara ◽  
Jagath K Premachandra

Corrosion is a severe matter regarding the most of metal using industries such as the crude oil refining. The formation of the oxides, sulfides or hydroxides on the surface of metal due to the chemical reaction between metals and surrounding is the corrosion that  highly depended on the corrosive properties of crude oil as well as the chemical composition of ferrous metals since it was expected to investigate the effect of Murban and Das blend crude oils on the rate of corrosion of seven different ferrous metals which are used in the crude oil refining industry and investigate the change in hardness of metals. The sulfur content, acidity and salt content of each crude oil were determined. A series of similar pieces of seven different types of ferrous metals were immersed in each crude oil separately and their rates of corrosion were determined by using their relative weight loss after 15, 30 and 45 days. The corroded metal surfaces were observed under the microscope. The hardness of each metal piece was tested before the immersion in crude oil and after the corrosion with the aid of Vicker’s hardness tester. The metallic concentrations of each crude oil sample were tested using atomic absorption spectroscopy (AAS). The Das blend crude oil contained higher sulfur content and acidity than Murban crude oil. Carbon steel metal pieces showed the highest corrosion rates whereas the stainless steel metal pieces showed the least corrosion rates in both crude oils since that found significant Fe and Cu concentrations from some of crude oil samples. The mild steel and the Monel showed relatively intermediate corrosion rates compared to the other types of ferrous metal pieces in both crude oils. There was a slight decrease in the initial hardness of all the ferrous metal pieces due to corrosion.


1977 ◽  
Vol 12 (1) ◽  
pp. 27-50 ◽  
Author(s):  
L.A. Behie ◽  
J.E. Zajic ◽  
D. Berk ◽  
R.J.P. Brouzes ◽  
V.A. Naish

Abstract Although Daphnia magna have been widely used in the determination of the toxicity of various substances, there are no reports in the literature that describe a rigorous bioassay method using this organism as a test species. The test described herein involves the standariza-tion of various important aspects of the method such as the age of the test organisms, and the dilution water used for the preparation of the various toxicant concentrations. Also described is a simple method for the statistical analysis of the results. The sensitivity of the proposed bioassay is demonstrated by determining the toxicity of various pulp and paper effluents. Finally, extensive bioassays were carried out simultaneously with rainbow trout and Daphnia magna indicating that Daphnia are as good a biological indicator of acute toxicity as fish.


Resources ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 75
Author(s):  
Ivelina K. Shishkova ◽  
Dicho S. Stratiev ◽  
Mariana P. Tavlieva ◽  
Rosen K. Dinkov ◽  
Dobromir Yordanov ◽  
...  

Thirty crude oils, belonging to light, medium, heavy, and extra heavy, light sulfur, and high sulfur have been characterized and compatibility indices defined. Nine crude oil compatibility indices have been employed to evaluate the compatibility of crude blends from the thirty individual crude oils. Intercriteria analysis revealed the relations between the different compatibility indices, and the different petroleum properties. Tetra-plot was employed to model crude blend compatibility. The ratio of solubility blending number to insolubility number was found to best describe the desalting efficiency, and therefore could be considered as the compatible index that best models the crude oil blend compatibility. Density of crude oil and the n-heptane dilution test seem to be sufficient to model, and predict the compatibility of crude blends.


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