Water-soluble Fraction Of Oil Research Articles

Efficient Removal of Water Soluble Fraction of Diesel Oil by Biochar Sorption Supported by Microbiological Degradation

The contamination of the water bodies by diesel oil (DO) and its water-soluble fraction (WSF) represents one of the most challenging tasks in the management of polluted water streams. This paper contains data related to the synthesis and characteristics of the plum stone biochar material (PmS-B), which was made from waste plum stones (PmS), along with its possible application in the sorption of the WSF of DO from contaminated water. Techniques applied in sample characterisation and comparisons were: Elemental Organic Analysis (EOA), Scanning Electron Microscopy−Energy Dispersive X-ray Spectroscopy (SEM-EDX), Fourier Transform Infrared Spectroscopy (FTIR), pH (pHsus) and point of zero charge (pHpzc). In order to increase the overall efficiency of the removal process, sorption and bioremediation were subsequently combined. Firstly, PmS-B was used as a sorbent of WSF, and then the remaining solution was additionally treated with a specific consortium of microorganisms. After the first treatment phase, the initial concentration of diesel WSF was reduced by more than 90%, where most of the aromatic components of DO were removed by sorption. The sorption equilibrium results were best fitted by the Sips isotherm model, where the maximum sorption capacity was found to be 40.72 mg/g. The rest of the hydrocarbon components that remained in the solution were further subjected to the biodegradation process by a consortium of microorganisms. Microbial degradation lasted 19 days and reduced the total diesel WSF concentration to 0.46 mg/L. In order to confirm the non-toxicity of the water sample after this two-stage treatment, eco-toxicity tests based on a microbial biosensor (Aliivibrio fischeri) were applied, confirming the high efficiency of the proposed method.

Performance of <i>Pistia stratiotes</i> (L.) as affected by water soluble fractions of Universal Energy Akwa Ibom crude oil in Abraka, Delta State, Nigeria

Environmental pollution and degradation caused by the processing and refining of crude oil has been on the increase since its discovery in the Niger Delta region of Nigeria. Its negative impacts are unquantifiable though its refined products are of immense benefits to the nation and the world at large. An assessment of the performance of Pistia stratiotes as affected by the water soluble fraction of Universal Energy Akwa Ibom crude oil was carried out in Abraka, Delta State, Nigeria in 2023. The five levels of WSF (0, 10, 25, 50, 75 and 100%) were used. Pistia stratiotes thalli were obtained from below the Bridge along River Ethiope and exposed to the different treatments. The results showed a significant reduction (p≤0.05) in all the plant parameters measured (leaf area, plant number, fresh weights, dry weight biomass, relative growth rate and survival percentage) in plants grown in the WSF media when compared to their counterparts exposed to the control plots. Against the normal healthy plants observed in the control, signs of dieback, yellowness of leaves, suppress growth and deaths were observed in plants subjected to the water soluble fraction of the crude oil and the effects were WSF dose dependent. There was gradual reduction in the shoot biomass of the plant with increasing level of WSF. There is a gradual increase in the root biomass although there was a total root growth. The study has established that the performance of Pistia stratiotes was significantly affected by the presence of water soluble fraction of crude oil. The study has great implication on water biology and food security. Continuous environmental monitoring and remediation exercises should be conducted in oil producing communities by the government.

GROWTH PERFORMANCE AND SELECTED BIOCHEMICAL INDICES ASSESSMENT IN THE SERUM AND LIVER OF CLARIAS GARIEPINUS JUVENILES EXPOSED TO VARYING CONCENTRATIONS OF WATER SOLUBLE FRACTION OF CRUDE OIL

The effect of varying concentrations (0, 0.25, 0.05 and 1.0% v/v) of water soluble fraction (WSF) of crude oil on the growth performance and biochemical changes in the serum and liver of 144 Clarias gariepinus Juveniles stocked into 12 glass aquaria at the rate of 12 fish per tank in triplicate for 90 days was assessed. The growth performance indices of the fish juvenile over the 90 days of toxic exposure revealed that the mean weight gained, specific growth rate, and total feed intake of the fish specimen decreases with increase concentration of the WSF of crude oil. However, 10% and 20% mortality were recorded in the fish exposed to 0.5% and 1.0% WSF of crude oil respectively. The activity of ALT and AST in the serum of the fish were significantly higher (p<0.05) with the increased concentration of WSF of crude oil while the ALT and AST activity of the liver of the fish juveniles irrespective of the added concentration of WSF of crude oil showed no significant differences (p>0.05). The study concluded that WSF of crude oil had adverse effects on the growth performance, blood serum and liver activities in C. gariepinus juveniles.

The effects of the water-soluble fractions of crude oil on liver and kidney tissues of Caspian Kutum juveniles, Rutilus frisii

The lethal and histopathological impacts of crude oil's Water-Soluble Fraction (WSF) on the liver and kidney tissues of juvenile Rutilus frisii were investigated. The LC50 96 h of WSF was calculated at 33.95 ppm. Fish exposed to two concentrations (0.1 LC50 and LC50) of WSF and control for 24 and 96 h were used for histopathological studies. Tissues in the control group and 0.1 LC50–24 h were healthy, and no specific damages were observed. With increasing exposure time (96 h) and concentration (LC50), damages' type, frequency, and intensity gradually increased. Cloudy swelling, loss of cell boundary, nuclei deformation, and congestion of blood vessels were found in the liver, enlarged glomeruli, reduced Bowman's space, and occlusion of the tubular lumen, were found in the kidney. It is demonstrated that the WSF of crude oil can cause severe damage to the tissues of juvenile Kutum, depending on the exposure concentration.

Effects of chronic exposure to the water-soluble fraction of crude oil and in situ burn residue of oil on egg-bearing Northern shrimp (Pandalus borealis)

Oil spill clean-up measures using in situ burning can potentially result in seafloor contamination affecting benthic organisms. To mimic realistic exposure and measure effects, ovigerous Northern shrimp were continuously exposed for two weeks to the water-soluble fraction of oil coated on gravel followed by two weeks in clean seawater. North Sea crude oil (NSC) and field generated in situ burn residue (ISBR) of NSC were used (Low: 3 g/kg gravel, Medium: 6 g/kg gravel and High: 12 g/kg gravel). The concentrations of polyaromatic hydrocarbons (PAHs) in the water resulting from NSC were higher compared to ISBR. No mortality was observed in any treatment and overall moderate sublethal effects were found, mostly after exposure to NSC. Feeding was temporarily reduced at higher concentrations of NSC. PAH levels in hepatopancreas tissue were significantly elevated following exposure and still significantly higher at the end of the experiment in NSCHigh and ISBRHigh compared to control. Mild inflammatory response reactions and tissue ultrastructural alterations in gill tissue were observed in both treatments. Signs of necrosis occurred in ISBRHigh. No change in shrimp locomotory activity was noted from NSC exposure. However, ISBR exposure increased activity temporarily. Larvae exposed as pleopod-attached embryos showed significant delay in development from stage I to stage II after exposure to NSCHigh. Based on this study, oil-contaminated seafloor resulting from in situ burning clean-up actions does not appear to cause serious effects on bottom-living shrimp.

Simulated Ageing of Crude Oil and Advanced Oxidation Processes for Water Remediation since Crude Oil Pollution

Crude oil can undergo biotic and abiotic transformation processes in the environment. This article deals with the fate of an Italian crude oil under simulated solar irradiation to understand (i) the modification induced on its composition by artificial ageing and (ii) the transformations arising from different advanced oxidation processes (AOPs) applied as oil-polluted water remediation methods. The AOPs adopted were photocatalysis, sonolysis and, simultaneously, photocatalysis and sonolysis (sonophotocatalysis). Crude oil and its water-soluble fractions underwent analysis using GC-MS, liquid-state 1H-NMR, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), and fluorescence. The crude oil after light irradiation showed (i) significant modifications induced by the artificial ageing on its composition and (ii) the formation of potentially toxic substances. The treatment produced oil oxidation with a particular effect of double bonds oxygenation. Non-polar compounds present in the water-soluble oil fraction showed a strong presence of branched alkanes and a good amount of linear and aromatic alkanes. All remediation methods utilised generated an increase of C5 class and a decrease of C6–C9 types of compounds. The analysis of polar molecules elucidated that oxygenated compounds underwent a slight reduction after photocatalysis and a sharp decline after sonophotocatalytic degradation. Significant modifications did not occur by sonolysis.

Risk Analysis of Crude Oil Contamination on Quality of Drinking Water for Some Sources of Freshwater

The main goal of this study was to see how water-soluble fractions of light crude oil from the Taq taq refinery influenced those physicochemical parameters in drinking water from the Dukan River and Sarchnar spring sources. According to statistical analysis, water quality parameters such as pH, electrical conductivity, temperature, turbidity, color, total solids, total dissolved solids, total suspended solids, ammonium, sulfide, and phosphorus have all been impacted by this crude oil when compared to controls (water resources) and drinking water quality standards. The results showed that the values of turbidity, color, ammonium, sulfide, and phosphorus in water samples that have been treated with various percent of crude oil water-soluble fractions are increased due to the high effects of crude oil on the physical and chemical characteristics of water resources (% 0 controls). According to our findings, the effect of crude oil contamination on water quality has been linked to a variety of factors.

Glycolic acid and formic acid production from pyrolysis oil water-soluble fraction by catalytic oxidation

The production of valuable chemicals and fuels from pyrolysis oil or its fractions is an appealing strategy. Glycolic acid and formic acid have widespread applications in the food processing and chemical industries. Here we investigated the feasibility of generating glycolic acid and formic acid from pyrolysis oil water-soluble fraction (WS) using H3PMo12O40·nH2O catalyst. Firstly, in order to clarify the possible reaction pathways in WS oxidation process, levoglucosan and glycolaldehyde, two principal substances present in WS, were respectively used as the substrate for oxidation to the two acids. Secondly, in order to find the optimum reaction conditions, the conversion of a mixture of levoglucosan and glycolaldehyde, as a surrogate of WS, was investigated under various process conditions. Thirdly, the actual WS was tested under the optimum reaction conditions, and the result gave a glycolic acid yield of 15.7% and a formic acid yield of 27.4%. Owing to the negative effects of phenols, cyclopentanones and furans in it, the result was different from that obtained with model mixture as substrate, in terms of the total yield of the two acids and the selectivity of glycolic acid over formic acid. Among various purifying methods of WS, activated carbon adsorption was effective, which resulted in a glycolic acid yield of 31.7% and a formic acid yield of 23.6%, making the conversion result of processed WS close to the conversion result of model mixture.

Pathological alterations in response to water soluble fraction of Iranian crude oil in gill of yellow fin sea bream Acanthopagrus latus (Houttuyn, 1782)

Water soluble fraction (WSF) of crude oil can pollute water and cause histopathological alterations in fishes. Therefore, sea water pollution with crude oil could detrimentally impact the fish health. The aim of the present study was to evaluate the effect of different concentrations of WSF on gills of yellow fin sea bream. The fish were exposed to 0% (control), 2%, 4%, 8% and 16% of WSF for a period of 21-days. The histopathological alterations were examined in four categories of circulatory, degenerative, proliferative and inflammatory. Inclusion of WSF at concentrations of 4%, 8% and 16% led to significant elevation of total petroleum hydrocarbon concentration in water (p 0.05). In conclusion, the findings of the present study indicated concentration and period of exposure as determinant factors influencing the level of alterations in gills histopathological lesions following exposure to WSF in yellow fin sea bream.

Biomonitoring of aromatic hydrocarbons in clam Meretrix meretrix from an emerging urbanization area, and implications for human health.

Pollution with total petroleum hydrocarbons (TPHs) is a global concern and particularly in coastal environments. Polycyclic aromatic hydrocarbons (PAHs) are regarded as the most toxic components of TPHs and they can also be derived from other sources. Fangcheng Port is considered as a representative emerging coastal city in China, but the status, sources, and hazards to organisms and humans with respect to contamination with PAHs and TPHs are unknown in the coastal regions of this area. Therefore, in this study, we cloned cytochrome P450 family genes (CYP1A1, CYP3A, and CYP4) and heat shock protein 70 gene (HSP70) in the clam Meretrix meretrix as well as optimizing the method for measuring the 7-ethoxyresorufin O-deethylase activity. These molecular indicators and four specific physiological indexes were found to be appropriate biomarkers for indicating the harmful effects of PAHs and TPHs on clams after exposure to the crude oil water-soluble fraction. In field monitoring surveys, we found that the 2- and 3-ring PAHs were dominant in the clams whereas the 4- to 6-ring PAHs were dominant in the sediments at each site. The PAH levels (3.63-12.77ng/g wet weight) in wild clams were lower, whereas the TPH levels (13.25-70.50μg/g wet weight) were higher compared with those determined previous in China and elsewhere. The concentrations of PAHs and TPHs in the sediments (19.20-4215.76ng/g and 3.65-866.40μg/g dry weight) were moderate compared with those in other global regions. Diagnostic ratio analysis demonstrated that the PAHs were derived mainly from pyrogenic sources. The TPHs may have come primarily from industrial effluents, land and maritime transportation, or fishing activities. The Integrated Biomarker Response version 2 indexes indicated that the clams collected from site S5 exhibited the most harmful effects due to contamination by PAHs and TPHs. Human health risk assessments demonstrated that the risks due to PAHs and TPHs following the consumption of clams can be considered acceptable. Our results suggest that continuous monitoring of contamination by PAHs and TPHs is recommended in this emerging coastal city as well as assessing their human health risks.

Hematotoxic Effect of Water Soluble Fraction of Bonny Light Crude Oil in Wistar Albino Rats

This study evaluated the Hematotoxic effect of water soluble fraction (WSF) of Bonny Light Crude Oil (BLCO) in Wistar Albino rats. After preparation of the WSF and a range finding test, the Wistar albino rats were administered three concentrations (25%, 50% and 100%) of WSF of BLCO for 30 and 60days. Data from the study showed that there was a significant decrease (p≤0.05) in PCV values (30.2% in the control group to 17.2% in the 100% group), Hb levels decreased significantly from 9.25 g/dl in the control group to 5.27 g/dl in the 100% group. WBC count decreased significantly from 2932 mm3 in the control group to 136 mm3 in the 100% group and finally RBC count decreased significantly from 241.8E4 mm3 to 567 mm3 with increasing concentrations in the treatment groups after 60days administration. These results suggest that the oral consumption of the WSF of BLCO led to an onset of anaemia which indicates the presence of less than normal concentrations of PCV, Hb and RBC.

Nephrotoxicological Effect of Water Soluble Fraction of Bonny Light Crude Oil in Wistar Albino Rats

This study evaluated the Nephrotoxic effect of water soluble fraction (WSF) of Bonny Light Crude Oil (BLCO). After preparation of the WSF and a range finding test, the Wistar albino rats were administered three concentrations (25%, 50% and 100%) of WSF of BLCO for 30 and 60days. Data from the study showed that Urea concentration increased significantly (p≤0.05) with increasing dose of BLCO ranging from 14.71 mg/dl in the control to 35.28 mg/dl in the 100% group after 30days and 14.28 mg/dl in the control to 41.08mg/dl in the 100% group after 60days, Creatinine concentration increased significantly (p≤0.05) from 0.22 mg/dl in the control to 0.82mg/dl in the 100% group after 60 days administration while electrolyte (Na, K, Cl) concentration increased significantly (p≤0.05) with increasing dose of BLCO after 60days administration. Histopathological examination of the kidney was characterized by partial partitioning of the glomerular tufts, obliteration of the Bowman’s capsule and distortion of the renal tubules. The findings in this research suggest that WSF of BLCO induced nephrotoxicity.

Water soluble fractions of crude oil deteriorates water quality parameters and alters histopathological components of juvenile Clarias gariepinus

In this study, the water quality changes after the introduction of water soluble fractions of crude oil were monitored along-side the accompanying effects on histopathological changes in selected organs of juvenile Clarias gariepinus . After a preliminary short-term (96 hours) static toxicity tests, fish were exposed to four sub-lethal concentrations (30, 45, 60 and 75 % of the LC 50 corresponding to 67, 101, 135 and 169 mg/l respectively) and a control group containing clean water using a semi-static renewal method for 90 days. Water quality parameters, heavy metals and total petroleum hydrocarbon (TPH) were determined using standard methods. After the exposure period, liver, brain and gill were harvested, labeled and prepared for photomicrography. Chloride, conductivity, salinity, magnesium, biochemical oxygen demand, chemical oxygen demand, total dissolve solids, turbidity and nitrate levels increased significantly (p 0.05). Values of TPH increased (p<0.05) with increasing concentrations of the crude oil. All analysed heavy metals followed a direct proportional trend as their values increased (p<0.05) alongside concentrations. Several histopathological alterations were found in the liver (sinusoidal congestion, atrophy of hepatocytes, hepatocellular degeneration and diffuse coagulation necrosis of hepatocytes), brain (vascular congestion and atrophy of neurons, neuronal necrosis, gliosis and loss of neurons) and gill (moderate loss of the secondary gill lamellae, moderate lamellae atrophy and moderate diffuse lamellae hyperplasia). The intensity of these lesions increased with increase in exposure dose. Keywords: Toxicity, Petroleum, Heavy metals, Water quality, Organs, Clarias gariepinus , LC 50

Impact of crude oil water soluble fraction on soil physiochemical properties and bacteria

Owing to the underlying negative impact of crude oil to the ecosystem, this study investigated the effect of water soluble fraction (WSF) of crude oil on selected soil physiochemical properties and bacteria using appropriate standard methods. The investigation was carried out using control (without WSF), 2, 5, 10 and 20% concentration for 42 days and analysis was carried out at day 0, 14, 28 and 42 using standard protocol. The result showed that WSF treatment increased the concentration of physicochemical properties especially for day 0 while as the time of exposure increased their concentration decreased. A significant ( p <0.05) increase in THC, nitrate, electrical conductivity and sodium ion at day 0 across from control to 20% and a similar result at day 14 for nitrate, however as concentration increased with time a significant decrease was observed except for sodium which had little or no changes. pH decrease with time from day 0 to day 14 and maintained a steady concentration afterwards. Potassium, calcium and magnesium ion conc. decreased significantly ( p <0.05) for each time (Day 0, 14, 28 and 42). Bacteria count decreased as exposure time increased, and increased with concentration within specific time. Bacteria count significantly decreased at day 0, increased significantly at WSF 20% for day 14 and 28 while an insignificant decrease was observed at day 42 when compared with control. This result suggests that consistent contamination with WSF could adversely alter the soil physiochemical properties and decrease soil bacteria count leaving just hydrocarbon degrading bacteria such as Pseudomonas spp. and Bacillus subtilis to thrive. Oil spillage site should be prevented or promptly remediated to maintain soil physicochemical properties and indigenous microbes essential for soil fertility and Nutrient availability to plants. Keywords: Water soluble fraction, Oil spillage, Soil Physiochemical properties, Soil Bacteria

Effects of the water-soluble fraction of a crude oil on freshwater meiofauna and nematode assemblages

Oil water-soluble fractions (WSFs) compounds have low persistence in water; evaporating in a matter of hours to days. Nonetheless, they pose high toxicity to exposed biota. Their effects may be instantaneous or delayed, affecting, respectively, mainly survival vs growth and reproduction. We investigated the effects of crude oil WSFs on freshwater meiobenthos, with a focus on nematode assemblages, in community microcosm experiments lasting 15 weeks. Treatments consisted of the application of different concentrations of oil WSFs, i.e. high (100%) medium (50%) and low (10%), and effects were assessed one, three, nine and 15 weeks after contamination, allowing us to detect both short-term and lasting effects of oil-WSF. Additionally, we compared the effects of a single contamination event with those of a so-called ‘constant’ oil-WSF contamination where we replenished evaporated water with water containing the medium concentration of oil WSF. Next to nematodes, the most abundant meiofaunal taxa were rotifers, gastrotrichs, oligochaetes and tardigrades. Total abundance, different diversity indices, the composition of feeding-types and the age structure were investigated in the assessment of direct oil effects on the structure of nematode assemblages. Limited immediate effects were observed, except for a significant decrease of the index of taxonomic distinctness, which already appeared in the first week. Significant impacts on total nematode abundance, diversity and species composition only became apparent after 9–15 weeks of incubation, indicating that delayed effects of a single exposure are far more pronounced than instantaneous effects. Moreover, for most response variables, the strongest impacts were not observed in the highest-concentration treatment, but in a medium-concentration treatment with regular replenishment of oil WSF, suggesting that internal exposure may be important in generating effects. Furthermore, the predictability of the sensitivity of individual species was sometimes poor, which may not only result from these species' sensitivities, but also from alterations in interspecific interactions in polluted communities. Further toxicity tests should be carried out in order to unravel the main modes of action of crude oil WSF which lead to the observed long-term sublethal effects on nematode communities.

Toxicokinetics of Crude Oil Components in Arctic Copepods.

The risk of accidental oil spills in the Arctic is on the rise due to increased shipping and oil exploration activities, making it essential to calibrate parameters for risk assessment of oil spills to Arctic conditions. The toxicokinetics of crude oil components were assessed by exposing one lipid-poor (CIII) and one lipid-rich (CV) stage of the Arctic copepod Calanus hyperboreus to crude oil WSF (water-soluble fraction). Water concentrations and total body residues (BR), as well as lipid volume fractions, were measured at regular intervals during exposure and recovery. Bioconcentration factors (BCFs) and elimination rates ( ke) for 26 petrogenic oil components were estimated from one-compartment models fitted to the BR data. Our parameters were compared to estimations made by the OMEGA bioaccumulation model, which uses the octanol-water partitioning coefficient ( KOW) in QSAR (quantitative structure-activity relationship) predictions. Our parameters for the lipid-poor CIIIs generally agreed with the OMEGA predictions, while neither the BCFs nor the kes for the lipid-rich CVs fitted within the realistic range of the OMEGA parameters. Both the uptake and elimination rates for the CVs were in general half an order of magnitude lower than the OMEGA predictions, showing an overestimation of these parameters by the OMEGA model.

Pyrolysis oil polymerization of water-soluble fraction during accelerated aging

Pyrolysis oil is a promising material for renewable energy through a hydrogenation process. However, the polymerization, initiated especially by pyrolysis oil water-soluble fraction (PS), is a big hurdle to hydrogenation. The types and structures of the polymerization chemicals, their polymerization mechanisms are very important for upgrading pyrolysis oil. This study firstly compared the polymerization rates of water-soluble fraction (PS) and water-insoluble fraction (PL) by accelerating aging fresh PS and PL at different temperatures (80 °C, 90 °C, 100 °C and 110 °C) for 24 h and at 110 °C for different durations (12 h, 24 h, 36 h, 48 h and 60 h), respectively. The thermogravimetric and differential thermogravimetry analysis results showed that PS polymerized much more rapidly than PL. Then, PS polymerization was further investigated by evaluating the changes in its physical properties (water content, viscosity and element content) and chemical compositions (gas chromatography and liquid chromatogram) before and after aging. The results showed that hydroxy aldehydes and ketones (especially glycoaldehyde, hydroxyacetone and levoglucosan), dicarbonyl compounds (especially succindialdehyde) and α, β-unsaturated carbonyl compounds (especially 3-methyl-2-cyclopenten-1-one and dehydrate resultants of some aldol condensation products) were mainly responsible for PS polymerization.

Direct toxicity of the water-soluble fractions of a crude and a diesel-motor oil on the survival of free-living nematodes

The water-soluble fraction (WSF) of an oil contains different classes of petroleum hydrocarbons and, despite their low potential for bioaccumulation, these can be highly toxic to biota. Nematodes are usually the most abundant and species-rich group of metazoans in marine and freshwater sediments as well as terrestrial soils and have been proposed as excellent models to monitor pollution effects. The first aim of this study was to assess the direct effects of the WSFs of a crude and a diesel-motor oil on the survival of 12 free-living bacterivorous nematode species from marine, freshwater and soil environments, and belonging to diverse taxonomic groups. The second aim was to compare the responses of these twelve test species and assess their suitability as candidate alternatives for the common model species Caenorhabditis elegans in future toxicity testing. The third and final aim was to test the common assumption that nematodes which are phylogenetically more closely related would exhibit more similar sensitivities than more distantly related species, and that – as is commonly stated in literature – nematodes belonging to the family Rhabditidae would be the most pollution-tolerant species. While the crude oil was a complex matrix of substances, containing many soluble compounds, the diesel-motor oil 10W40 was characterized by only few soluble substances. Nevertheless, the diesel-motor oil WSF was as toxic (or even more toxic) to some of the tested nematode species as the crude-oil WSF. This could be linked to differences in compounds interactions in each oil-WSF, or to the presence of fuel additives in the 10W40-WSF. Most species exhibited moderate to extreme mortality levels in oil treatments, and experienced an increased mortality with time. Overall, marine nematodes were more sensitive than freshwater/soil organisms, albeit with some exceptions. Species sensitivities to oil did not follow patterns of taxonomic relatedness, contradicting the idea that closely related species should intrinsically respond similarly to pollution. Rhabditidae were not generally more sensitive than other species: out of 6 species of Rhabditidae tested, only Bursilla monhystera was highly tolerant, while C. elegans and cryptic species of Litoditis marina were among the most sensitive taxa. Therefore, we recommend that future effect studies do not focus on a single model species but instead incorporate multiple species for a better and more robust assessment of pollutant effects.

Avoidance threshold to oil water-soluble fraction by a juvenile marine teleost fish.

When oil spills occur, behavior is the first line of defense for a fish to avoid being contaminated. We determined the avoidance threshold of the European seabass (Dicentrarchus labrax) to the water-soluble fraction (WSF) of oil using a dual-flow choice box. The results showed that a plume of 20%-diluted WSF (total polycyclic aromatic hydrocarbon [PAH] concentration: 8.54 μg L-1 ) triggered a significant avoidance response that was detected within 7.5 min of introducing WSF-contaminated water into the experimental setup. However, the ecological relevance of seabass capacity to detect and avoid WSF remains to be established. In the short term, such a response is indeed liable to reduce seabass contact time with oil-contaminated water and thus preserve their functional integrity. In the long term, however, avoidance may contribute to the displacement of a population into a possibly less auspicious environment, with consequences very similar to those of contaminant exposure, that is, disturbed population dynamics and demography. Environ Toxicol Chem 2018;37:854-859. © 2017 SETAC.

Evaluation of Haematological and Biochemical Parameters of Juvenile &lt;i&gt;Oreochromis niloticus&lt;/i&gt; after Exposure to Water Soluble Fractions of Crude Oil

The influence of water soluble fraction of crude oil from Afiesere oil field on water quality components and its consequent effect on haematological and biochemical parameters in juveniles of Oreochromis niloticus were evaluated. After a preliminary determination of the 96 h-LC 50 of crude oil by probit regression was found to be 92.38 mg/l, fish were exposed to 4 sub-lethal concentrations (30, 45, 60 and 75% of the LC 50 corresponding to 28, 41, 55 and 69 mg/l respectively) of the oil and a control. After 84 days of exposure, blood was collected and used in conducting haematological and biochemical analyses. Exposure of water to crude oil caused increased levels in chloride, conductivity, salinity, magnesium, biochemical oxygen demand, chemical oxygen demand, turbidity and Nitrate. The crude oil contaminated water resulted in a significant reduction (p<0.05) in the values of red blood cells, packed cell volume and haemoglobin. Although no definite trend in the values of computed haematological indices was observed, MCHC, however, decreased with increased concentration. Also, Glucose, ALP, ALT, AST, Urea and creatinine activities of all the affected set of fish, which have been exposed to the crude oil were significantly higher (p<0.05) in comparison to their respective control. Keywords : Crude oil, Afiesere oil field, blood, toxicity, water quality, Oreochromis niloticus