Bay Crude Oil Research Articles

EFFECT OF VARIABLES ON PERFORMANCE OF SURFACE WASHING AGENTS UNDER A NEWLY DEVELOPED TESTING PROTOCOL

ABSTRACT Surface washing agents (SWAs) can be used following an oil spill event to enhance the removal of stranded oil from shorelines and other surfaces. The U.S. Environmental Protection Agency (EPA) has developed a testing protocol to evaluate the effectiveness of SWAs in the laboratory. Using this protocol, the effects of substrate type, substrate hydration, and SWA-to-oil ratio (SOR) on the ability of SWAs to remove crude oil were evaluated. Experiments were conducted using Prudhoe Bay Crude (PBC) oil applied to three substrates under wet and dry conditions. Oil recovery efficiencies were similar for substrates made up of sand and the smaller of two gravels, while a decrease in efficiency was observed for the larger, more heterogeneous gravel. For the controls without SWA, after we compared dry and wet substrates, we decided dry substrates would be preferable for purposes of the protocol because variability was much lower and differences between treated and control samples were greater. To determine the effect of SOR, four SWAs were evaluated at three SORs and two dilutions for their efficiency in removing PBC from dry sand. Oil recovery efficiency as a function of SOR was lower at the low SOR ratios (1:1 <2:1 <10:1). Application of equivalent volumes of 50% and 100% SWA solutions to PBC revealed that efficiency increased with applied mass of SWA. However, when equal masses of SWA were applied at 10:1 SOR, similar efficiencies were achieved regardless of dilution. This suggests that, except at the highest application rate, total applied mass is a more critical variable than dilution for these SWAs. IFO180 Fuel Oil was also evaluated under these conditions. Preliminary data suggest lower SWA efficiencies were observed with this heavier weight oil.

Morphological and neurotoxicological findings in tropical freshwater fish (Astyanax sp.) after waterborne and acute exposure to water soluble fraction (WSF) of crude oil.

The water-soluble fraction (WSF) of crude oil is a complex highly volatile and toxic mixture of hydrocarbon chains (polyaromatics, heterocyclics), phenols, and heterocyclic compounds containing nitrogen and sulfur. To evaluate the toxic effects of WSF in tropical freshwater teleosts and to develop methodologies that could investigate the toxic mechanisms of WSF in tropical organisms, an acute toxicity experiment was conducted with Astyanax sp. Three dilutions (15%, 33%, and 50%) of WSF obtained from Campos Bay's crude oil (Brazil) were used to study morphological and biochemical responses of the fish. Prior to exposure, the distribution and rate of volatilization of the WSF into each aquarium for the same exposure period was quantified by spectrofluorimetry. Five individuals of Astyvanax sp. were exposed to duplicate WSF of 0, 15, 33, and 50% for each of 12-, 24-, and 96-h exposures for a total of 120 individuals. Liver and gills were sampled from five fish from each treatment and were analyzed by histology, scanning and transmission electron microscopy. A fragment of muscle was also collected from each fish to measure acetylcholinesterase activity. Water analysis showed that only 4 h after dilution, an important loss of hydrocarbons in 33% and 50% of WSF was observed. In addition, 50% of hydrocarbon mass was lost in all tested dilutions after 24 h with significant difference for the 50% WSF at all measured times, demonstrating the high volatility of WSF in freshwater. Damage in the liver and the gills included the presence of necrosis, loss of hepatocytes limit, inflammation areas, cellular proliferation, aneurysms, and disorganization of the second lamellae. The 33% WSF significantly reduced acetylcholinesterase activity in fish. Our study demonstrated that the WSF of crude oil caused damage in organs and tissues of tropical freshwater Astyanax sp. and provided also the basis for a better understanding of the toxic mechanisms of WSF in freshwater fishes.

A Review of Oil-in-Water Monitoring Techniques: The Concluding Results

ABSTRACT A comprehensive laboratory study of the Turner Instrument flow-through models 10AU and 10 fluorometers was conducted to review their ability to measure real-time oil-in-water concentrations and to further understand the relationship of the fluorescence to the chemical composition of the oils. The oils and dispersant used in the program were Alberta Sweet Mixed Blend (ASMB) crude oil (0% and 26% weathered samples), Prudhoe Bay (PB) crude oil (0% and 27% weathered samples), Bunker C (BC) fuel oil (0% and 8.4% weathered samples), Diesel fuel (0% and 37% weathered samples) and Corexit 9500 respectively. The chemical composition of the oils was determined by gas chromatographic techniques and compared to the signal outputs of the fluorometers. It was found that the fluorometer data could not be directly linked to the concentration of any specific aromatic hydrocarbon such as naphthalene or to the sum of the polycyclic aromatic hydrocarbon (PAH) compounds. Evidence suggests that the fluorescence signal is generated by a combination of PAH compounds. The relative contribution of each PAH compound is not equal. Finally, the response of the fluorometers may also be influenced by the presence of volatile aromatic compounds such as BTEX and C3- benzenes in combination with the PAH compounds.

Development of a Rational Oil Spill Dispersant Effectiveness Protocol

ABSTRACT Chemical dispersants are used in oil spill response operations to enhance the dispersion of oil slicks at sea as small oil droplets in the water column. To be considered for use, the dispersants must be listed in the National Contingency Plan (NCP) Product Schedule. Since 1994, dispersants were required to pass an effectiveness test known as the Swirling Flask Test (SFT), which is described in Appendix C of 40 CFR 300. Listing of a dispersant on the NCP Product Schedule is contingent on the dispersant being at least 45% effective in dispersing South Louisiana crude (SLC) and Prudhoe Bay crude (PBC) oils as measured and calculated by the test. Shortly after adopting the SFT, the U.S. Environmental Protection Agency (EPA) began to receive complaints that the test was too rigorous and few dispersants that were previously listed on the NCP Product Schedule could achieve the 45% effectiveness criterion. Additionally, the SFT has been found to give widely varying results in the hands of different testing laboratories. A redesign of the test flask, which is characterized as being baffled with a stopcock at the bottom for undisturbed sample collection, is considered to be necessary to accomplish reproducibility within operators and between operators. This paper presents the development of a revised procedure for dispersant effectiveness testing, called the Baffled Flask Test (BFT), and reports the reproducibility of the revised procedure by three independent operators. It also details the development of pass/fail selection criteria. Experimental results are presented comparing the repeatability of the SFT and BFT methods with three operators determining the effectiveness of 18 dispersants on SLC and PBC oils. Statistical analysis of the results indicated that the overall mean effectiveness of the SFT for all 18 dispersants was only 19.7% compared to 64.6% by the BFT and the coefficient of variation for the SFT was 21.9% versus only 7.8% for the BFT.

The systemic toxicity of Prudhoe Bay crude and other petroleum oils to CD-1 mice

CD-1 mice were given oral doses of 0-16 ml/kg/day for five days of Prudhoe Bay (PBCO), South Louisiana and Arabian Light crude oils, Bunker C oil (BCO), mineral oil (MO) and corn oil. Minor decreases in packed cell volume and increases in mean corpuscular hemoglobin concentration occurred after ingestion of crude oils and BCO. Dietary depletion of vitamin E and selenium failed to enhance hematological changes. Pronounced liver enlargement and atrophy of thymus and spleen accompanied ingestion of all petroleum oils except MO and were shown to be dependent on dose of PBCO. Concentration of RNA and total RNA were increased while total DNA, but not concentration of DNA, was increased in enlarged livers. Liver enlargement was attributed primarily to hyperplasia with an additional contribution due to hypertrophy. The severe hemolytic anemia reported in marine birds that ingested PBCO was not reproduced in mice. Liver enlargement and lymphoid tissue atrophy were similar to those reported in other species exposed to petroleum oils.