Oil Concentration In Water Research Articles

Investigation on the permeation-diffusion combination action mechanism for a novel oil storage method: The flexible oil storage in waters

A novel oil storage method utilizing flexible oil bladders to store oil in waters is proposed. The proposed method has the advantages of conserving land resources and economic cost, high fire and explosion protection performance. And it does not require an oil-water displacement method. However, the application of the proposed method is severely limited by oil pollution. To overtake the limitation, the permeation-diffusion combination action mechanism of flexible oil storage in waters is investigated. The analytical solution of oil concentration distribution in water under the permeation-diffusion combination action is presented, of which the accuracy is verified by model experiment and numerical simulation. The results indicate the oil concentration in water can quickly reach a stable value that is directly proportional to the oil permeation rate of membrane material. Simultaneously, the oil permeation rate standard of ellipsoid bladder is suggested to be 1.436 × 10−6g/m2s and the interval between oil bladders is set at 1.5 times of the bladders diameter. Furthermore, a relationship equation has been given between the thickness of membrane and oil permeation rate. This study offers theoretical and engineering guidance for the application of flexible oil storage in waters and has certain significance for the development of underwater oil storage.

Technology development of producing adsorption material from cereal crops waste for accidental oil spill response

The article considers the developed technology of producing sorption material based on chemically and thermally modified cereal grain husks for removing accidentaloil spillsfrom water surface. Equipment, modes and conditions for modifying the surface of a new adsorption material in order to increase the sorption capacity in relation to oil and construction of mats are proposed. The calculated cost of the resulting modifiers is tenstimes lower than the standard adsorbents used inaccidental oil spill responses. Additionally, a threefold use of treated sorption material based on modified crops waste by pressing has been theoretically justified. It is proposed to incinerate the waste generated as a result of accidental oil spillremoval from the water surface in a pulsate combustion unit at a temperature of 1100 °C. The hazard class of ash generated during combustion has been determined – class 3. Semi-industrial tests with the proposed modified materials for the elimination of emergency oil spills on the surface of an unnamed stream have been carried out. As a result, the concentration of oil in water decreased by 99.99 %, as well as toxicity.

Preparation of Thymus vulgaris (L.) essential oil nanoemulsion and its chitosan encapsulation for controlling mosquito vectors

Here, we report a novel comparative assessment of preparation and characterization of thyme oil nanoemulsion and its chitosan encapsulation using high energy approach for the management of three major mosquito species viz., Anopheles stephensi (Liston,1901), Aedes aegypti (Linn., 1762) and Culex tritaeniorhynchus (Giles, 1901). The synthesized formulations were analysed for thermodynamic stability, indicating 1:0.5 (oil: surfactant) ratio to be the most stable of thyme oil nanoemulsion while 1:1 (nanoemulsion: chitosan solution) ratio of its chitosan encapsulation. These were further characterized by dynamic light scattering and transmission electron microscopy which revealed the size and morphology of the droplets which measured 52.18 ± 4.53 nm for thyme oil nanoemulsion and 50.18 ± 2.32 nm for its chitosan encapsulation. All the droplets were well dispersed with distinct flower-shaped nanoemulsion and somewhat mitochondria like chitosan encapsulation. In-vitro release study of thyme essential oil from its nanoemulsion and chitosan encapsulation showed that 91.68% and 73.41% of the total oil concentration in water was released respectively to the environment after 48 h clearly depicting controlled release in the encapsulation. Assessment of insecticidal potential against selected mosquito species revealed that both the nanoemulsion and its chitosan encapsulation were effective on the major mosquito species. Maximum activity of thyme oil nanoemulsion was noticed against C. tritaeniorhynchus (LC50—22.58 ppm) after 24 h of exposure while it was observed that its chitosan encapsulation was most effective on A. stephensi (LC50—18.88 ppm) after 24 h of exposure. Consistent morphological alterations could be noticed in the larvae of mosquito species. Hence, these nanoemulsions and encapsulations could be further tested for their applications against other insect pests in agriculture.

Calculation of winding temperature of a submersible motor

The article is devoted to the issue of control and regulation of the high-quality operation of a submersible motor with a long overhaul period. There are some complications of operating the electric submersible pump. One of them is the thermal interaction of the borehole fluid and components and parts of the electric submersible pump that leads to failure and repair. It is necessary to conduct research in the field of physical and hydrodynamic calculations to determine the effect of heat exposure. The article reveals one of the approaches to solving the problem of thermal interaction between a well and the electric submersible pump. We describe calculations of the winding temperature of a submersible electric motor for specific conditions in a particular well, including different modes of fluid flow, different loads of the submersible motor, and different concentrations of oil in water. The development of the described technique will allow creating special software aimed at determining the areas with the highest temperature of the motor winding, taking into account various parameters that affect the heat transfer process.

Influence of pH and temperature of dip-coating solution on the properties of cellulose acetate-ceramic composite membrane for ultrafiltration

Polymer-ceramic composite membranes were prepared by dip coating technique using 5 wt.% cellulose acetate (CA) solution at different temperatures (15 °C, 25 °C and 40 °C). The effect of pH (2–12) of the polymeric solution on the properties of the membranes was studied using SEM, EDAX, FTIR, gas and liquid permeation. The thickness of the polymeric layer depended on the interaction of CA solution with the surface of ceramic support. Membrane permeability decreased with increase in pH because of decrease in pore size and porosity resulting from strong interaction of the polymer layer with the ceramic support. The porosity and mean pore size of the prepared membranes were found to be 28–60% and 30–47 nm (ultrafiltration range), respectively. The optimized membrane (pH 7) was used for ultrafiltration of oil in water emulsions (100 and 200 mg/L). Oil rejection of 99.61% was obtained for 100 mg/L of oil concentration in water.

CYPS MOLECULAR BIOMARKERS IN RAINBOW TROUT Oncorhynchus mykiss TO ASSESS OIL CONTAMINATION IN A PATAGONIAN STREAM

Cytochrome P450 (CYP) gene expressions were studied by semi-quantitative polymerase chain reaction (PCR) to assess oil pollution using liver and gills of juvenile rainbow trout Oncorhynchus mykiss sampled from La Mina stream (Bariloche, Argentina), up and downstream of a discharge of petroleum spill from an unproductive wellbore. Data was complemented with laboratory exposure to water accommodated fraction (WAF) from the oil spill. Oil exposure induced gill and liver CYP1A transcription (1.2-1.4-fold), which was used as reference biomarker. In both organs, CYP2K1 transcript was induced after 5 % WAF exposure, 24 h (1.8-2.0-fold), and it was down-regulated in more extended time (1.2-1.5-fold). CYP2M1 transcript levels were down-regulated in liver of impacted wild trout and in trout exposed to 5 % WAF during 96 h (1.5-1.7-fold). CYP2K1 and CYP2M1 are involved in the metabolism of fatty acids and estrogenic hormones, and its down-regulation would indicate metabolic alterations. CYP3A27 levels were only induced in liver of wild trout (1.6-fold), possibly related to crosstalk between aryl hydrocarbon receptor and pregnane X receptor signaling pathway. While CYP1A mRNA expression appears to be a more robust biomarker for detecting the effects of crude oil under different dose and exposure time, the expression of CYP2K1, CYP2M1 and CYP3A27 mRNAs would indicate different time exposure to oil pollution, particularly under high oil concentration in water. Hence, patterns of multiple CYP genes expression in rainbow trout gills and liver could be especially valuable for monitoring programs of crude oil pollution and remediation actions on Patagonian freshwater ecosystems.

A biooptical model of retrieving petroleum concentration in seawater

A biooptical modeling, which is based on a radiation transfer model, can be employed to simultaneously retrieve the concentration of various colour factors by multi-spectral remote sensing data, after connecting inherent optical properties (absorption coefficient and backward scattering coefficient) of colour factor with apparent optical properties (remote sensing reflectivity). At present, this method has been used in a relatively wide range of applications in the inversion of a conventional water colour factor concentration in the case II water body: applications such as chlorophyll, suspended sediment, yellow substance. On the basis of extensive field testing data of water quality, correspondingly apparent optical properties, and the full use of the existing parametric model of colour factor inherent optical properties (with the parametrization of petroleum substance inherent optical properties established in the project) the remote recognition model for oil concentration is established by introducing oil as a new water colour factor into a biooptical remote algorithm. The estimated value of the oil concentration was obtained by solving the biooptical model, using the data measured in May 2008 and August 2009 and June 2010 in seawater. The highly accurate inversion result promises to estimate the oil concentration in water for remote sensing.

沈船からの流出油に対する油処理剤の水中散布による分散性能に関する研究

Experiment to investigate the dispersive effects of underwater dispersant, namely, the reduction of rise velocity of oil droplets and the increase of diffusion area, have been carried out. A beaker test of mixed sample of Marine Diesel Fuel (MDF) and dispersant was carried out and the particle size distribution was measured to confirm the pertinent ratio of dispersant. As the dispersant is a solution of nonionic surfactant and hydrocarbon solvent, the relation between hydrocarbon solvent and MDF was investigated by Gas Chromatography (GC) analysis. The oil concentration in water was confirmed to be linear to the oil dispersant ratio. As the dispersant reacts to water, the mixed sample of MDF and dispersant was discharged from the nozzle installed at the bottom of a water tank 3 m in height. The behavior of this mixed sample was analyzed by high resolution camera. PTV, PIV, and concentration change method were used to analyze the rise velocity and diffusion area of the sample. It turned out that the reduction of rise velocity of oil droplets and the increased diffusion area of the sample were the effect of the dispersants. Furthermore, the rise velocity of oil droplets was estimated from the size of oil particles.

MEDSLIK-II, a Lagrangian marine surface oil spill model for short-term forecasting – Part 1: Theory

Abstract. The processes of transport, diffusion and transformation of surface oil in seawater can be simulated using a Lagrangian model formalism coupled with Eulerian circulation models. This paper describes the formalism and the conceptual assumptions of a Lagrangian marine surface oil slick numerical model and rewrites the constitutive equations in a modern mathematical framework. The Lagrangian numerical representation of the oil slick requires three different state variables: the slick, the particle and the structural state variables. Transformation processes (evaporation, spreading, dispersion and coastal adhesion) act on the slick state variables, while particle variables are used to model the transport and diffusion processes. The slick and particle variables are recombined together to compute the oil concentration in water, a structural state variable. The mathematical and numerical formulation of oil transport, diffusion and transformation processes described in this paper, together with the many simplifying hypothesis and parameterizations, form the basis of a new, open source Lagrangian surface oil spill model, the so-called MEDSLIK-II, based on its precursor MEDSLIK (Lardner et al., 1998, 2006; Zodiatis et al., 2008a). Part 2 of this paper describes the applications of the model to oil spill simulations that allow the validation of the model results and the study of the sensitivity of the simulated oil slick to different model numerical parameterizations.

Optical Performance Evaluation of Oil Spill Detection Methods: Thickness and Extent

The release of petroleum liquids in water, such as marine, riverine, and lacustrine basins, is a matter of concern that shoves authorities and experts to adopt technical approaches for preventing damages, monitoring oil content in water and cleaning up environmental aqueous matrices. In this paper, a dedicated system for oil spill detection is presented. The proposed system consists of an optical fiber sensor and an image processing unit useful to steer and optimize the measurement process. An optical fiber-based antenna sensor is used to detect the oil concentration in water. The sensor consists of two slanted optical probes acting as transmitter and receiver, respectively. Both probes are completely immersed into water being analyzed. The sensing approach is based on the measurement of the light coupling level affected by the reflectivity of the oil layer floating on the water surface. The experimental measurement of different types of oil is performed to assess the sensitivity of the developed system. Special attention is put on the image postelaboration useful to derive the characteristics of the oil distribution on the water surface. In this respect, two different image processing techniques are considered: the first one is based on a suitable energy-minimizing spline fitting procedure subject to external constraint forces, whereas a judicious use of the Hough transform is made in the second one.

Research on All Fiber-Optical Fluorescence System Measuring Mineral Oil in Water

A fluorescent optical fiber measuring system used to measure the concentration of the mineral oil in water is put forward in this paper according to the mechanism that the mineral oil in watercan emit fluorescence when excited by ultraviolet light. The pulse xenon lamp is used as excitation light source, while the linear CCD is adopted as the fluorescent signal of photoelectric detection components instead of the traditional photomultiplier tube in the system, combining with the optical fiber sensor technology and weak signal detection technology. It also equipped with the data acquisition card to realize data receiving and A/D conversion, using micro computer to store and display the data. This in turn realizes the accurate measurement of the concentration of mineral oil in water. The fluorescence optical fiber measuring system that used to measure the concentration of the mineral oil in water has the characteristics of simply structure, high sensitivity, wide linear range, probe passive and so on. The experimental result shows that this method is completely feasible.

Study on Three-Dimensional Fluorescence Spectra of Oil Concentration in Water

According to the Lambert-Beer laws, the fluorescence spectra of oil in water were investigated by measuring excitation-emission matrixes with FS920 fluorescence spectrometer. On the basis of the three-dimensional fluorescence spectra of oil in water, the excitation wavelength of 290nm and emission wavelength of 324nm were chosen for the quantitative analysis of oil in water. The results show that the concentration of oil in water is linearly proportional to the fluorescence intensity in the range of 1ppm-100ppm, and the measurement model of concentration is obtained with the linear correlation coefficient of 0.9993. The artificial samples has also been tested and the results are satisfactory. The recovery is in the range of 92%-106%. The research provides experimental basis for the quantitative analysis of multi-component oil in water.

Governing factors for motor oil removal from water with different sorption materials

This paper has been focused on the sorbent efficiency for motor oil removal from water. Two types of sorbents were investigated: organic and inorganic. Natural wool fibers (NWFs) and recycled-wool-based nonwoven material (RWNM)) were tested as organic type of sorbents. Sepiolite, bentonite and zeolite have been chosen as representative inorganic sorbents. Sorption was carried out in batch sorption system. Efficiency of oil removal was determined by measuring the oil concentration before and after the sorption process. Extractive-gravimetric method and refractive index determination have been applied as analytical methods for determination of oil concentration in water. Governing factors for sorbent efficiency were proposed, analysed and compared. It was concluded that sorption process is mostly affected by mass of sorbent, sorption time, temperature and pH value of water. NWFs, which were the most efficient sorbent showed maximal efficiency and maximal sorption capacity: 0.1 g of NWFs after 10 min at 20 °C and pH 8.00 sorbed 3.3 g of motor oil from 300 mL of water polluted with 4.5 g of motor oil. Maximal efficiency for all sorbents investigated was reached after 30 min of sorption processes, it was 95.0% for NWF, 43.0% for NRWM, 20.7% for sepiolite, 19.6% for bentonite and 21.2% for zeolite. Physical adsorption onto all sorbents is a favorable process (sorption efficiency decrease with increasing temperature) while sorption onto bentonite and zeolite is a result of both physical adsorption and chemisorption (sorption efficiency increase with increasing temperature, up to 80 °C).

Rapid in situ determination of total oil concentration in water using ultraviolet fluorescence and light scattering coupled with artificial neural networks

Real-time measurement of total oil concentration in complex samples is required in wastewater discharge streams from ships and processing industries. A novel technology has been developed for the accurate quantification of a variety of single oils and their mixtures. Four major types of oils (lube oils 2190 and 9250, diesel fuel marine (DFM), and jet fuel (JP5)), each of which consisted of a dozen subtypes of oil samples, were examined to obtain both fluorescence and light scattering spectra as a function of concentration of single oils and mixtures. Tremendous variations in both fluorescence and scattering were observed among oil types, subtypes, and mixtures. The spectral response of an oil mixture was not the simple summation of respective single oils. To account for all these variations, a multivariate, nonlinear calibration method is applied to associate instrumental responses with oil concentrations using artificial neural networks (ANNs). The neural network architecture has been established by optimizing network parameters such as epochs, the number of neurons in the hidden layer, and learning rates in order to achieve the maximum accuracy of oil concentration measurements. It is demonstrated that the simultaneous, combined use of fluorescence and light scattering significantly improves the accuracy of measurement for oil samples. The newly developed technique permits the reliable, real-time determination of the total concentration of various oils and mixtures in water.

Fluorescence diagnostics of oil pollution in coastal marine waters by use of artificial neural networks.

We discuss the problems with and the real possibilities of determining oil pollution in situ in coastal marine waters with fluorescence spectroscopy and of using artificial neural networks for data interpretation. In general, the fluorescence bands of oil and aquatic humic substance overlap. At oil concentrations in water from a few to tens of micrograms per liter, the intensity of oil fluorescence is considerably lower than that of humic substances at concentrations that typically are present in coastal waters. Therefore it is necessary to solve the problem of separating the small amount of oil fluorescence from the humic substance background in the spectrum. The problem is complicated because of possible interactions between the components and variations in the parameters of the fluorescence bands of humic substances and oil in water. Fluorescence spectra of seawater samples taken from coastal areas of the Black Sea, samples prepared in the laboratory, and numerically simulated spectra were processed with an artificial neural network. The results demonstrate the possibility of estimating oil concentrations with an accuracy of a few micrograms per liter in coastal waters also in cases in which the contribution from other organic compounds, primarily humic substances, to the fluorescence spectrum exceeds that of oil by 2 orders of magnitude and more.

PAH metabolites in bile, cytochrome P4501A and DNA adducts as environmental risk parameters for chronic oil exposure: a laboratory experiment with Atlantic cod

In order to perform environmental risk assessments with regard to oil contamination in the sea, it is important to obtain knowledge about threshold levels for possible adverse effects in marine organisms. With this objective in mind, selected biomarkers were studied in Atlantic cod ( Gadus morhua) chronically exposed to mechanically dispersed crude oil. The fish were exposed for 30 days in a continuous flow system to nominal concentrations of 0.06, 0.25 and 1 ppm North Sea crude oil. Fish were sampled five times during the exposure period. In addition, the 1 ppm group and the control group were sampled 1 week after the end of exposure. Polyaromatic hydrocarbon (PAH) concentrations in the seawater were analysed regularly by direct fluorescence and, at one occasion, by gas chromatography with mass spectrographic detection (GC/MS) measurements. Liver samples were analysed for parent PAH levels by means of GC/MS measurements, and PAH metabolites in bile were analysed by means of fixed wavelength fluorescence. Cytochrome P450 induction in liver was estimated by ethoxyresorufin- O-deethylase (EROD) activity, and hepatic DNA adducts were analysed by the 32P-postlabelling assay. The parent PAH concentrations in liver showed peak levels 3 days after the start of exposure, followed by a reduction towards the end of the experiment. In contrast, the PAH metabolites in bile and EROD activity showed generally increasing levels throughout the whole exposure period, indicating an increased biotransformation efficiency. The level of DNA adducts in the 1 ppm group showed a stable increase during the entire exposure period. Only a slight, non-significant decrease in DNA adduct levels was observed after 7 days of recovery in clean water. Exposure-dependent responses were observed for all three biomarkers. The lowest nominal concentration of dispersed oil in water, 0.06 ppm, corresponded to a measured total PAH concentration in the water of 0.3 ppb. Atlantic cod exposed to this concentration showed increased levels of PAH metabolites in bile and a slight induction of CYP1A, as well as formation of DNA adducts when compared with control fish. Particularly noteworthy is the detection of DNA adducts at such a low exposure concentration of oil in water, which, to our knowledge, is a novel finding. These dose–response data may serve as useful contributions when assessing environmental risk with regard to marine oil pollution.

Alkyl polyglucoside microemulsion phase behavior

We review several key elements of alkyl polyglucoside (C mG n) microemulsion phase behavior. The low solubility of C mG n surfactants in oils such as alkanes makes producing C mG n microemulsions and subsequent study of their phase behavior difficult. Increasing the solubility of C mG n in oil is therefore helpful for the systematic study of C mG n-based microemulsion formulations. To this end, the role of cosurfactants in producing microemulsions with water, alkanes, and n-alkyl β- d-glucopyranosides is first discussed. Adding C 10βG 1 to mixtures of water–alkane–ethoxylated alcohol surfactants (C iE j) produces a region of the three-phase body (a ‘chimney’) that is independent of temperature; thus C mβG 1 are not completely soluble in the co-oil formed of alkane and C iE j at higher temperatures. Then, through a novel approach using oxygenated ether oils (C kOC 2OC k), microemulsions are formed with water, C kOC 2OC k, and C mβG 1 and the phase behavior studied as a function of temperature and composition. Increased C mβG 1 solubility in the more hydrophilic ether oils produces patterns of phase behavior in water–C kOC 2OC k–C mβG 1 mixtures that are identical to those observed in water–alkane–C iE j mixtures. Using the water–ether oil–C mβG 1 mixtures as a base case, the role of C mG n surfactant structure in setting C mG n microemulsion phase behavior is explored. The solubility of the α- d anomer (n-alkyl α- d-glucopyranosides, C mαG 1) in water is much less than that of the β- d surfactant, and these solubility boundaries extend to high surfactant and oil concentrations in water–C kOC 2OC k–C mαG 1 mixtures. Adding C mG 2 compounds to water–C kOC 2OC k–C mβG 1 mixtures shifts the phase behavior to high temperatures, again demonstrating the extreme hydrophilic nature of the sugar headgroup. Finally, adding small amounts of ionic alkyl sulfate surfactants to water–C kOC 2OC k–C mβG 1 mixtures dramatically reduces the total amount of surfactant needed to form a single-phase microemulsion.

Application of pulsed photoacoustics in water at high pressure

The application of pulsed photoacoustics to the study of liquids at pressures of up to 350 bars is discussed. The design and development of an in-line sensor for the subsea monitoring of crude oil concentrations in water is reported. Crude oil detection sensitivities at parts per million concentrations were achieved with prototype instrumentation. A comparison of experimental results and a theoretical prediction of the pressure dependence of the pulsed photoacoustic response from water is outlined. The results demonstrate that existing models that describe pulsed photoacoustic generation in liquids are applicable to high-pressure conditions.

Hydrocarbon concentrations in the northern North Sea and effects on fish larvae

Two surveys were carried out in 1993 and 1994 to measure the concentrations of oil in water and the associated effects on fish larvae along two north-south sections (between 57.00°N and 62.00°N at longitude 0.0°E and 1.5°E) through the northern North Sea. At each station occupied hydrocarbon concentrations were logged continuously from a towed in situ fluorimeter attached to a MIKT net used to sample larvae and deployed on an oblique tow from surface to bottom. The results show a distinct north-south gradient in hydrocarbon concentration peaking around installations associated with oil and gas exploration and production. Depth averaged data show that the mean concentration in the top 50 m was between 3 and 4 μg l−1 at latitudes between 56.00 and 59.00°N falling to values as low as 0.2–0.5 μg l−1 in the more pristine waters to the north and west. The hydrocarbon levels in the top 50 m between 56.00 and 59.00°N were elevated compared to those in deeper water. 7-Ethoxyresorufin O-deethylase (EROD) activity was measured in pooled samples of both sandeel and gadoid larvae. For both species the range of EROD activities was large and variable and this is probably due to damage to larvae associated with capture and subsequent denaturation of the enzyme. Despite this the results show elevated EROD activity in samples taken on the southern end of the transect where hydrocarbon fluorescence in the water was highest and there is a significant regression of EROD activity on hydrocarbon concentration. The results therefore suggest a significant elevation of hydrocarbons in a large area of the northern North Sea (5–10 times the true background) and that these concentrations are capable of inducing biological responses associated with deleterious effects in fish larvae.

ECOLOGICAL EFFECTS OF OIL VERSUS OIL PLUS DISPERSANT ON THE LITTORAL ECOSYSTEM OF THE BALTIC SEA

ABSTRACT The effects of a North Sea oil with or without the addition of dispersant were studied in a model of the littoral ecosystem of the Baltic Sea. Experiments were carried out in six pools with a volume of 8 m3 each, with flowthrough seawater and an ecosystem of the shallow rocky Baltic archipelago. All major fauna and flora were transferred into the pools in normal numbers and proportions. Two of the pools were exposed to oil alone. The amount of oil was equivalent to 20 ppm assuming total mixture. Two other pools were exposed to the same amount of oil and an oil dispersant (Corexit 9550, Exxon), and two pools served as controls. The effects studied were those on abundance of heterotrophic bacteria, periphyton photosynthesis, growth of bladder wrack, phytoplankton growth, zooplankton abundance and diversity, benthic fauna, physiological responses of certain crustaceans and molluscs, and the growth of blue mussels. In addition, the total photosynthesis and respiration of the ecosystem was studied. Concentrations of oil in water and in blue mussels were monitored. The experiments showed that almost all the measured parameters were affected. When comparing the effects between the pools, several of the results indicated a stronger response for oil alone compared to oil and dispersant. This was particularly obvious when monitoring the total production and respiration of the ecosystems. The explanation may be that the ecosystems in the pools exposed to oil and dispersant were exposed less time compared to those in the pools where oil alone was added. The oil and dispersant mixture obviously left the system much faster due to the water exchange compared to the oil without dispersant. In the latter case the oil adhered to surfaces and detritus and thus tended to stay longer in the environment. These results may provide valuable information for decision makers faced with an oil spill in shallow waters and who have an option to use oil spill dispersant.