Chemical characterization of a water soluble fraction (WSF) of crude oil

Very polar oil compounds are predominant in the resulting water soluble fraction (WSF) of crude oil, in agreement with their high solubility in seawater. Non‐volatile hydrocarbons represent only a low proportion of total soluble extracts.

The experimental process we have achieved allows us to obtain quantitative and reproducible soluble oil extracts that could be used in ecotoxicological tests and for the study and the characterization of marine oil pollution.     

Individual and combined toxicity of some petroleum aromatics to the marine amphipod Elasmopus pectenicrus

Toxicity of 4 components of petroleum oils to the marine amphipod Elasmopus pectenicrus (Bate) has been assessed. Two ephemeral aromatic hydrocarbons, naphthalene (A) and 1, 2, 4-trimethylbenzene (B) were more toxic than two persistent aromatics, o-cresol (C) and o-toluidine (D). The acute toxicity concentrations obtained for individual aromatic compounds were always greater than the actual concentrations found in the water-soluble fractions (WSF) of fuel oils. Results from mixtures of 2 or more components indicated that the LC₅₀ levels were primarily determined by the more toxic substances, A and B. Naphthalene and 1, 2, 4-trimethylbenzene became more toxic to the E. pectenicrus when present in a mixture of more than 2 components, and the toxicity increased with increasing numbers of components present. Synergistic effects, therefore, possibly occur in the whole WSF. No antagonistic effects were observed among the 4 petroleum aromatics.University of Texas, Marine Science Institute Contribution No. 290     

Water-soluble components of four fuel oils: Chemical characterization and effects on growth of microalgae

Approximately 50% of the compounds in the water solubles from 4 fuel oils have been identified via gas chromatography and mass spectrometry. In addition to the well-described types of compounds (naphthalenes, benzenes) expected in water-soluble extracts we have found phenols, anilines, and indoles. Of these classes of compounds methyl, dimethyl, and trimethyl derivatives are present in relatively high concentrations. The water solubles from the 4 fuel oils showed considerably different inhibitory effects to growth of 6 microalgae, 2 blue-greens, 2 greens, and 2 diatoms. Two of the fuel-oil extracts, Baytown and Montana, were lethal to blue-green algae. This was in part traceable to their content of p-toluidine which was found to be toxic to Agmenellum quadruplicatum, Strain PR-6, 1 g in the algal lawn-pad assay and 100 g/l in liquid culture. The water-soluble fraction from New Jersey fuel oil was lethal to the 2 green algae, with lesser effects on the 2 blue-greens. The 2 estuarine diatoms used as test organisms were not greatly inhibited by Baytown, Montana, or New Jersey fuel-oil water-soluble extracts. However, earlier work with an American Petroleum Institute fuel oil and the diatom Thallassiosira pseudonana (3H) showed that 3H was a very sensitive organism. Water solubles from the Baton Rouge fuel oil were almost without effect on the growth of all 6 microalgae. On the basis of the work herein and earlier work, a very cautious viewpoint is advisable in generalizing on the toxicity or lack thereof of a given fuel oil on the growth of different kinds of microalgae. On the other hand, with water solubles from toxic fuel oils such as Baytown or New Jersey the data clearly suggest that their potential for environmental damage is high, either through selective or enrichment effects on natural populations or through a lowering of total primary production.     

Characteristics of dispersions and water-soluble extracts of crude and refined oils and their toxicity to estuarine crustaceans and fish

The quantitative hydrocarbon composition and behavior in seawater of water-soluble fractions (WSF) and oil-in-water dispersions (OWD) of 4 oils was investigated. Two crude oils, South Louisiana crude and Kuwait crude, and two refined oils, No. 2 fuel oil and bunker C residual oil, were used in these investigations. The WSFs of the crude oils had higher total oil-hydrocarbon concentrations and were richer in light aliphatics and single-ring aromatics than were the WSFs of the refined oils. The WSFs of the refined oils contained significantly higher concentrations of naphthalenes than did those of the crudes. The hydrocarbon composition of the aqueous phase of OWDs closely resembled that of the parent oils. Gentle aeration of the OWDs resulted in a loss of 80 to 90% of the aqueous hydrocarbons in 24 h. Alkanes disappeared from the dispersions more rapidly than aromatics. The WSFs and OWDs of the refined oils were considerably more toxic to the 6 test species than were those of the crude oils. The test species can be ranked according to increasing sensitivity to oil as follows: Cyprinodon variegatus, Menidia beryllina, Fundulus similus, Penaeus aztecus postlarvae, Palaemonetes pugio and Mysidopsis almyra. The results of this investigation are discussed in relation to the potential impacts of oil spills on the marine and estuarine environments.     

Production of glycine betaine and dimethylsulfoniopropionate in marine phytoplankton. I. Batch cultures

The quantitative significance of the nitrogenous compound glycine betaine (GBT) and its sulfur analog dimethylsulfoniopropionate (DMSP) to intracellular pools in marine phytoplankton is not well known. In a series of experiments conducted in August 1993, we measured these compounds, as well as total organic sulfur, carbon, and nitrogen, over the growth cycle in six isolates of marine phytoplankton, Amphidinium carterae Hulburt, Chrysochromulina sp. Lackey, Emiliania huxleyi Hay et Mohler, Prorocentrum minimum (Pavillard) Schiller, Skeletonema costatum (Greville) Cleve, and Tetraselmis sp. At the same time, we measured cellular concentrations of protein, amino acids, chlorophyll, and inorganic nutrients. All six species produced DMSP, while three produced GBT at lesser levels. In the Chrysochromulina sp. isolate, levels of GBT were greater than DMSP during the exponential phase of growth, but declined sharply as the culture approached stationary phase. This change appeared to coincide with the onset of nitrogen limitation. Other nitrogenous osmolytes were produced in five of the six species but in much smaller quantities. DMSP contributed significantly to cellular sulfur throughout the growth cycle although, in some algae, the proportion of dissolved DMSP increased substantially during stationary growth. When present, GBT formed a sizeable fraction of the cellular nitrogen only during exponential growth. A significant percentage (ca. 50%) of the organic nitrogen could not be accounted for even when cellular pools of protein, amino acids, inorganic nitrogen, and nitrogenous osmolytes were combined. Based on these experiments, there does not appear to be a reciprocal relationship between DMSP and GBT production, although GBT production does appear to be correlated with nitrogen availability. Received: 5 January 1998 / Accepted: 29 June 1999     

Chemical composition and effects of water extracts of petroleum on eggs of the sand dollar Melitta quinquiesperforata

Sperm and eggs of sand dollars, Melitta quinquiesperforata (Leske), were subjected to two petroleum oils, and effects determined. The oils chosen were Kuwait crude and No. 2 fuel oil, supplied by the American Petroleum Institute. Water-soluble extracts (WSF) from oil-sea water mixes were prepared and the major aromatic components in the WSF of the fuel oil were identified. WSF of No. 2 fuel oil depressed respiration, mobility of sperm, interfered with fertilization and cleavage, and retarded larval development. The effects were detectable at dilutions of 4% and less (about 0.6 ppm of WSF). Kuwait crude was much less toxic. There was no effect on water permeability of the egg membrane. Results are compared with similar studies on other marine organisms.     

The effects of three oils on marine phytoplankton photosynthesis

The effects of 3 oils (Venezuelan crude, No. 2 fuel, and No. 6 fuel) on the photosynthesis of natural phytoplankton communities from Bedford Basin, Nova Scotia (Canada), and the northwest Atlantic Ocean between Halifax and Bermuda were examined using a radiocarbon method. The 3 oils can inhibit photosynthesis, and the degree of inhibition depends upon oil type and concentration. The No. 2 fuel oil was the most toxic. Under certain conditions, low concentrations of Venezuelan crude oil can stimulate photosynthesis. On the basis of these results, it is concluded that present levels of oil contamination in Bedford Basin could be inhibiting photosynthesis by a few percent, while present levels in open ocean water have no apparent deleterious effect on photosynthesis.Bedford Institute of Oceanography Contribution.     

Particulate and semivolatile associated aliphatic hydrocarbon exhaust emission from heavy duty diesel vehicles

The exhaust emissions from two heavy duty diesel vehicles running on eight different fuel compositions were investigated regarding their content of high molecular weight (≥ C₁₂) aliphatic/ olefinic hydrocarbons. It was concluded that the emitted amount of semi‐volatile associated aliphatic hydrocarbons (range C₁₂‐C₂₂) depend on the fuel used in the engines and that these emissions mainly consisted of uncombusted fuel components. It was also found that uncombusted engine lubrication oil was the main constituent of the emitted particulate associated aliphatic hydrocarbons (C₁₇‐C₄₀). These constituted between 58% and 95% of the total emissions of the high molecular weight aliphatic compounds. Emission factors for the total of high molecular aliphatic hydrocarbons (C₁₂‐C₄₀) were demonstrated to be in the range of 15–100 mg/km. Some individual aliphatic hydrocarbons with cocarcinogenic effects were identified and quantified in both particulate and semi‐volatile phases of the exhaust. Multivariate data analysis was used to investigate the relationship between fuel parameters and emission of semi‐volatile aliphatic emission.     

Short-term effect of microencapsulated hydrocarbons on shell growth of Mytilus edulis

Two North Sea crude oils, weathered crude oil, n-alkanes, medical liquid paraffin and a fish oil were microencapsulated and added to seawater. This gave a medium containing both water soluble fractions (WSF) and oil particles, and thus simulated the conditions in natural seawater contaminated with oil. The microencapsulated oils were fed to Mytilus edulis L. in different concentrations, and the growth in terms of shell length of the mussels was measured in intervals of 24 to 48 h for 4 to 12d. With the crude oilss A and B, weathered crude oil and n-alkanes at concentrations1 mg l^-1, shell growth rate decreased rapidly compared to controls. With liquid paraffin at levels of 1 to 12 mg l^-1, a small but significant negative effect on shell growth occurred after 5 d of exposure. Exposure to fish oil at 1 and 4 mg l^-1 gave no significant reduction in growth rate. The toxicity of the different hydrocarbons was not related to their content of aromatic fractions. Crude oil B was tested at concentrations ranging from 0.12 to 12 mg l^-1. At 0.12 mg l^-1 shell growth was not significantly different from the control, while at 0.25 and 0.50 mg l^-1 a temporary and significant stimulation of growth was observed. The product concentration (C)xresponse (R) shows a linear regression on exposure time (t). The regression model CxR=75-0.18t is used to estimate EC-values (effect of a given concentration) for given response levels. The model gives a very good fit to observed data.     

Biological effects of oil on early development of the Baltic herring Clupea harengus membras

The effects of petroleum hydrocarbons from two crude oils and one fuel oil (No. 1) were studied on the ontogenic development of the Baltic herring Clupea harengus membras L. Herring eggs exposed to water-soluble fractions of the oils at the time of fertilization showed no decrease in numbers of fertilized eggs compared to eggs exposed 6 or 72 h after fertilization. During embryongenesis, treatment with 3.1 to 8.9 ppm or 3.3 to 11.9 ppm total oil hydrocarbons from light fuel oil and the two crude oils respectively, gave rise to alterations in embryonic activity, decreased heart rate, and premature or delayed hatching. Although many larvae hatched from eggs exposed to contaminated water (3.1 to 11.9 ppm total oil hydrocarbons), the majority of the (70 to 100%) were malformed or dead 1 day after hatching. Exposure of eggs to 5.4–5.8 ppm total oil hydrocarbons resulted in significantly (P<0.001) decreased lengths of the larvae. Increased temperature (from 9° to 14°C) aggravated the effects of the oils. The results are discussed in relation to the potential effects of oil spills and chronic oil pollution on fish eggs and larvae in the Baltic Sea.     

Accumulation,fractionation and release of oil by the intertidal clam Macoma balthica

The bivalve mollusc Macoma balthica accumulated hydrocarbons during 180 days of continuous exposure to Prudhoe Bay crude oil in seawater dispersions with nominal concentrations of 0.03, 0.3 and 3.0 mg l^-1. The mollusc's ability to concentrate oil from seawater increased with decreasing oil-in-water concentration. Decreases in oil burden began after 30 to 120 days (depending on the oil concentration) and continued for at least 60 days after exposure to oil ceased. Aliphatic and aromatic hydrocarbons were fractionated in markedly different ways by the bivalve. Branched and cyclic aliphatics in the molecular weight-range dodecane through hexadecane were preferentially retained over straightchain and their higher homologs. Larger and more substituted aromatic compounds were selectively concentrated. There appeared to be no selective concentration of aromatic sulphur compounds.Please address requests for reprints to Dr. D. G. Shaw at the Institute of Marine Science     

The effects of a no. 2 fuel oil and two crude oils on the growth and photosynthesis of microalgae

Seawater, when equilibrated with a sample of No. 2 fuel oil, becomes toxic in varying degrees to growth of representative types of microalgae, two blue-greens, a diatom, two greens, and a dinoflagellate. For a sensitive organism such as Thalassiosira pseudonana, Strain 3H, 5 ml of seawater equilibrated with fuel oil (containing 15 mg/l of organics) in 20 ml of growth medium is lethal, or roughly in the range of 40 to 400 ppb if the toxic material(s) constitute 1 to 10% water also immediately stops photosynthesis in organism 3H. For other microalgae tested e.g. 580 (a green alga) and PR-6 (a blue-green alga), similar effects on growth and photosynthesis were found, but required higher concentrations of the oil-equilibrated seawater. Water solubles from Kuwait or Southern Louisiana crude oils (when the straight crude oil was equilibrated 1:8 with seawater) were not toxic; however, specific fractions obtained by distillation did show some water-soluble toxicity. Growth experimetns in open or closed growth systems revealed that most organisms were inhibited by varying amounts of these two crude oils when in direct contact with them. Organism 580 would not grow above 5 μl of Southern Louisiana/25 ml of medium, or 10 μl of Kuwait/25 ml of medium (oil in direct contact with algae). With both the seawater equilibrated with fuel oil and the crude oils, the toxic activity is mainly localized in medium and higher boiling fractions derived from distillation cuts from these materials.     

Making scents of defense: do fecal shields and herbivore-caused volatiles match host plant chemical profiles?

Many plant families have aromatic species that produce volatile compounds which they release when damaged, particularly after suffering herbivory. Monarda fistulosa (Lamiaceae) makes and stores volatile essential oils in peltate glandular trichomes on leaf and floral surfaces. This study examined the larvae of a specialist tortoise beetle, Physonota unipunctata, which feed on two M. fistulosa chemotypes and incorporate host compounds into fecal shields, structures related to defense. Comparisons of shield and host leaf chemistry showed differences between chemotypes and structures (leaves vs. shields). Thymol chemotype leaves and shields contained more of all compounds that differed than did carvacrol chemotypes, except for carvacrol. Shields had lower levels of most of the more volatile chemicals than leaves, but more than twice the amounts of the phenolic monoterpenes thymol and carvacrol and greater totals. Additional experiments measured the volatiles emitted from M. fistulosa in the absence and presence of P. unipunctata larvae and compared the flower and foliage chemistry of plants from these experiments. Flowers contained lower or equal amounts of most compounds and half the total amount, compared to leaves. Plants subjected to herbivory emitted higher levels of most volatiles and 12 times the total amount, versus controls with no larvae, including proportionally more of the low boiling point chemicals. Thus, chemical profiles of shields and volatile emissions are influenced by the amounts and volatilities of compounds present in the host plant. The implications of these results are explored for the chemical ecology of both the plant and the insect.     

Biogeochemistry of aromatic hydrocarbons in the benthos of microcosms†

Investigations into the fate of petroleum compounds in the marine environment were carried out using experimental microcosms of two sizes and designs. Aromatic hydrocarbons or No. 2 fuel oil were spiked to the water of a 13 m³ continuous flow system and to a 2281 recycled flow system. The transport and alteration of this oil was traced in the sediment and benthic organisms (Glycera americana, Crepidula sp., and Nephtys incisa) of these microcosms. Measurable contamination was found in both sample types. The aromatic hydrocarbon distribution, including relative isomeric distribution (e.g., C₂‐phenanthrenes) was found to be different in sediment and in organisms from that which was originally introduced to the experimental microcosm. Differences in isomer distribution between Glycera and Crepidula were also detected. Based on the experimental data: molecular weight and specific isomeric form, biochemical processes, solubility, and particle adsorption/desorption influence the fate of petroleum compounds in benthic ecosystems.     

Total organic sulfur and dimethylsulfoniopropionate in marine phytoplankton: intracellular variations

Cellular levels of particulate organic sulfur (POS) and dimethylsulfoniopropionate (DMSP) were determined in cultures of five species of marine phytoplankton, Amphidinium carterae, Prorocentrum minimum, Emiliania huxleyii, Dunaliella tertiolecta and Skeletonema costatum. The first three are known producers of DMSP while the latter two produce little or non-detectable amounts of DMSP. In those species which produced significant amounts of DMSP, intracellular levels of POS and DMSP varied for the dinoflagellates (A. carterae and P. minimum) while they remained fairly constant for the prymnesiophyte (E. huxleyii) over the growth cycle (until late stationary phase), and DMSP accounted for the majority of the POS (50 to 100%). In species with low levels of DMSP, intracellular POS and DMSP decreased or remained constant over the growth cycle, and DMSP accounted for a much lower percentage of the POS (0 to 40%). Species with high DMSP concentrations had higher POS levels per unit cell volume as well, and DMSP accounted for substantially higher percentages of the particulate organic carbon (POC). Molar N:S ratios suggest a non-protein origin for much of the sulfur in the species producing DMSP. During late stationary phase, an increasing percentage of the DMSP became extracellular in the dinoflagellate and diatom (S. costatum) cultures, suggesting leakage. In a bacterized algal culture, measured quantities were considerably less than in an axenic counterpart, suggesting consumption.     

Toxicity assessment of crude oils: A methodological view

As a continuity of efforts in the field of laboratory ecotoxicological studies of oil on marine organisms, the present work contains data showing to what extent the observed toxicity of two chemically dispersed crude oils (arabian light and heavy) on well succeeded fish culture species (Lebistes reticulatus) is tightly dependent on the instantaneous measured oil concentration in the bioassay media rather than the initial applied concentrations.     

渤海北部典型芳香烃类化合物污染状况及生态风险评价

为探究渤海北部海上油气区及周边近岸海域典型芳香烃类化合物污染状况,2015年5月现场采集了32个站位的海水样品,针对7种苯系物(BTEX)和17种多环芳烃(PAHs)进行测定,并采用商值法和毒性当量法对污染物开展单一和联合生态风险评估。结果显示,研究海域海水中7种苯系物总含量范围为65.1～222.6 ng·L~(-1),以甲苯含量最高,表层含量略低于底层,油气区平均含量低于周边近岸,受到陆源污染输入的影响特征明显。表层海水中ΣPAHs含量范围为98.9～356.0 ng·L~(-1),平均值为184.5 ng·L~(-1),以低环芳烃占优势,总体处于中等水平,比值法判定该海域PAHs可能主要来源于石油及其加工产品。该海域海水中苯并(a)芘的风险商RQ值大于0.1,表现出低度风险,其余3种处于可接受水平。4种芳香烃类化合物联合生态风险等级为低度风险,对生态系统具有潜在的不利影响,但不同区域仍存在一定差异性,海上石油开采与陆源输入是影响该海域个别区域生态风险较高的重要因素。     

Responses of Mytilus edulis on exposure to the water-accommodated fraction of North Sea oil

Individuals of Mytilus edulis L., collected from the Erme estuary (S.W. England) in 1978, were exposed to low concentrations (7 to 68 g l^-1) of the water-accommodated fraction (WAF) of North Sea crude oil. The pattern of accumulation of petroleum hydrocarbons in the body tissues was affected by the presence of algal food cells, the period of exposure, the hydrocarbon concentration in seawater, the type of body tissue and the nature of the hydrocarbon. Many physiological responses (e.g. rates of oxygen consumption, feeding, excretion, and scope for growth), cellular responses (e.g. lysosomal latency and digestive cell size) and biochemical responses (e.g. specific activities of several enzymes) were significantly altered by short-term (4 wk) and/or long-term (5 mo) exposure to WAF. Stress indices such as scope for growth and lysosomal latency were negatively correlated with tissue aromatic hydrocarbons.     

Detection of p34cdc2- and cyclin B-like proteins in Dunaliella tertiolecta (Chlorophyceae)

p34cdc2 and cyclin B are two key proteins in the eukaryotic cell cycle control machinery. They thus could be important cell cycle markers for studies of environmental effects on cell cycle progression and on growth rate of marine phytoplankton. From July 1993 to March 1995, we used commercially available antibodies to examine the presence of their homologs in a marine phytoplankton species, Dunaliella tertiolecta Butcher. A p34cdc2-like protein was detected on the Western blots, with an apparent molecular mass as expected (34 kDa). Anti-cyclin B detected a protein of 63 kDa, a size similar to that of cyclin B in other organisms. The two proteins decreased from the exponential to the stationary growth phase. As determined on the Western blots, their abundance only changed slightly during the cell cycle, being slightly more abundant prior to cell division. Immunofluorescence performed for a partially synchronized culture showed that the fraction of the cell population that was positively stained by anti-p34cdc2 was highest at the time when the culture was mainly in the late G1 or early S phase, and in the late G2 or early M phase, respectively. The fraction was low when the culture was mainly in the S phase. Although further characterization is required to verify their identities, these two growth phase-related proteins appear to be p34cdc2 and cyclin B homologs, which may be useful in studying the cell cycle and growth rates of phytoplankton.     

Identification of Anthropogenic Organic Contamination Associated with the Sediments of a Hypereutropic Tropical Lake, Venezuela

The concentrations of organic carbon (Corg), inorganic carbon (Cinorg), organic nitrogen (Norg) and total aromatic (Arom_T) were determined in 25 samples of bottom sediments from the Lake Valencia, Venezuela, as a contribution to the knowledge about pollution by organic compounds in tropical lakes. Results demonstrate that the Corg and Norg concentrations do not show the pollution indexes by themselves. This is a consequence of the masking effect of naturally derived organic matter from the decay of algae and organisms in the water column and terrestrial plants, which are transported to the lake. Nevertheless, the Arom_T concentrations and the normalised Arom_T (normalized to organic carbon) make it possible to detect organic matter of anthropogenic origin, in the Arom_T levels are about nine times higher than those natural. The variation in the band intensity of the IRFT spectra for some functional groups present in the saturate and aromatic hydrocarbon fractions gives an indication of anthropogenic contribution for some zones of the lake. With the ¹H NMR spectra it was not possible to differentiate a natural source from an anthropogenic one in the lake. Naturally occurring organic compounds (eicosane, pentacosane, and hexacosane) were detected with GC technique in the saturated hydrocarbon fraction. The presence of an unresolved complex mixture (UCM) in the GC chromatograms indicates pollution by branched and cyclic hydrocarbons. These compounds are probably produced by the incomplete combustion of oil products. Potentially toxic organic compounds such as anthracene, phenanthrene and chrysene were found in the aromatic hydrocarbon fraction, which despite presenting low concentrations (ppb order) accumulate in the lake sediments along with the natural source organic matter. The main access paths of organic pollutants to the lake are the rivers which cross the two urban and industrial areas (Maracay and Valencia cities). The mixture of polluted sediments with bottom natural sediments and the autochthonous contribution of organic matter mitigate the pollution levels progressively towards the center of the lake.