Water-soluble Fraction Of Crude Oil Research Articles

Study on the hematological toxicity of Cyprinus carpio exposed to water-soluble fraction of crude oil and TiO2 nanoparticles in the dark and ultraviolet

This study is addressing the potential toxicity concerns of crude oil in common carp (Cyprinus carpio) with the novel use of TiO2-NP for enhancing photocatalytic degradation of WSF of crude oil prepared under UV light or darkness. Blood samples were taken, and the biochemical parameters were analyzed. The levels of ALT, AST and ALP were significantly higher in fish exposed to UV-treated WSF. However, they were significantly lower in the groups exposed to UV-treated TiO2-NPs and the combination of WSF and TiO2-NPs. The levels of total protein, triglycerides, albumin and cholesterol were significantly lower in treatments exposed to UV-treated and dark-conditioned WSF compared to the control group, but they were significantly higher in fish exposed to UV-treated TiO2-NPs and the combination of WSF and TiO2-NPs compared to fish exposed under dark conditions and were not significantly different from the control group. The toxicity of UV-treated WSF was significantly higher than that of dark-conditioned WSF. The toxicity of TiO2-NPs was lower in the presence of UV and was similar to the control treatment. The results of the study suggests that photocatalytic TiO2-NPs and UV radiation reduce toxicity of the water-soluble fraction of crude oil on common carp.

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.

No observed developmental effects in early life stages of capelin (Mallotus villosus) exposed to a water-soluble fraction of crude oil during embryonic development

ABSTRACT The rise in offshore oil and gas operations, maritime shipping, and tourism in northern latitudes enhances the risk of oil spills to sub-Arctic and Arctic coastal environments. Therefore, there is a need to understand the potential adverse effects of petroleum on key species in these areas. Here, we investigated the effects of oil exposure on the early life stages of capelin (Mallotus villosus), an ecologically and commercially important Barents Sea forage fish species that spawns along the coast of Northern Norway. Capelin embryos were exposed to five different concentrations (corresponding to 0.5–19 µg/L total PAHs) of water-soluble fraction (WSF) of crude oil from 6 days post fertilization (dpf) until hatch (25 dpf), and development of larvae in clean seawater was monitored until 52 dpf. None of the investigated endpoints (embryo development, larval length, heart rate, arrhythmia, and larval mortality) showed any effects. Our results suggest that the early life stages of capelin may be more robust to crude oil exposure than similar life stages of other fish species.

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.

Effect of petroleum wastewater treated with gravity separation and magnetite nanoparticles adsorption methods on the blood biochemical response of mrigal fish (Cirrhinus cirrhosus).

Drainage of treated wastewater to surface water is a severe threat to the health of aquatic organisms. This study aimed to evaluate the effects of 0.5 and 1% water-soluble fractions of crude oil (WSFO), WSFO treated with magnetic nanoparticles of Fe3O4 (TWSFO-Fe3O4) and with the gravity separation method (TWSFO-GSM) on Cirrhinus cirrhosis for 21 days. The rate of erythrocyte hemolysis in fish exposed to untreated 0.5 and 1% WSFO were significantly high. The activities of alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP) were significantly increased in the groups exposed to TWSFO-GSM compared to the control group, while lactate dehydrogenase (LDH) was reduced. No significant differences in LDH, ALT, ALP, and GGT activities were observed in the fish treated with TWSFO-Fe3O4. The aspartate aminotransferase activity was significantly increased after exposure to TWSFO-Fe3O4 (1%) and TWSFO-GSM. The levels of triglyceride were decreased, whereas glucose, cholesterol, and cholinesterase activity increased in fish after both treatments. The total protein and albumin contents significantly decreased in fish under exposure to both doses of TWSFO-Fe3O4 and TWSFO-GSM. The globulin level decreased in fish exposed to TWSFO-Fe3O4 (1%) and TWSFO-GSM. Glutathione peroxidase, catalase, glucose-6-phosphate dehydrogenase activities, and total antioxidant levels were significantly reduced in the hepatocytes of fish exposed to TWSFO-Fe3O4, TWSFO-GSM, and WSFO, while superoxide dismutase activity and malondialdehyde content were increased. This study showed that despite removing oil drips from the WSFO, the xenobiotics present in the effluent treated by gravitational or nano-magnetite methods caused changes in biochemical parameters and induced oxidative stress. Therefore, it is recommended to prevent the discharge of treated effluent from the oil and petrochemical industries to aquatic ecosystems.

The effect of aqueous leaf extracts of Pterocarpus mildbraedii on crude oil-induced toxicity in Albino rats

ABSTRACT This study evaluated the ameliorative potential of the aqueous leaf extracts of Pterocarpus mildbraedii against crude oil-induced toxicity in rats. The effects of co-administration of the P. mildbraedii leaf extract with diets contaminated with water-soluble fraction of crude oil on biochemical and chromosomal indices in albino rats were studied. Rats were fed with the crude oil-contaminated diets and administered the aqueous P. mildbraedii leaf extract at 100, 300, or 500 mg kg−1 bwt for 6 weeks. The activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), and creatinine kinase-MB (CK-MB) as well as the concentrations of total protein, albumin, total bilirubin, creatinine, and urea in the plasma of experimental rats were estimated. Bone marrow cells obtained from the femurs of the rats were scored for chromosomal aberrations. Results showed that the administration of the P. mildbraedii leaf extract restored the levels of the plasma enzymes, blood proteins, urea, and creatinine close to normal control levels, which were altered by the crude oil-contaminated diet, and the number of chromosomal aberrations were fewer in treated rats than in the untreated intoxicated rats.

Combined effects of exposure to engineered silver nanoparticles and the water-soluble fraction of crude oil in the marine copepod Calanus finmarchicus

While it is likely that ENPs may occur together with other contaminants in nature, the combined effects of exposure to both ENPs and environmental contaminants are not studied sufficiently. In this study, we investigated the acute and sublethal toxicity of PVP coated silver nanoparticles (AgNP) and ionic silver (Ag+; administered as AgNO3) to the marine copepod Calanus finmarchicus. We further studied effects of single exposures to AgNPs (nominal concentrations: low 15 μg L−1 NPL, high 150 μg L−1 NPH) or Ag+ (60 μg L−1), and effects of co-exposure to AgNPs, Ag+ and the water-soluble fraction (WSF; 100 μg L−1) of a crude oil (AgNP + WSF; Ag++WSF). The gene expression and the activity of antioxidant defense enzymes SOD, CAT and GST, as well as the gene expression of HSP90 and CYP330A1 were determined as sublethal endpoints. Results show that Ag+ was more acutely toxic compared to AgNPs, with 96 h LC50 concentrations of 403 μg L−1 for AgNPs, and 147 μg L−1 for Ag+. Organismal uptake of Ag following exposure was similar for AgNP and Ag+, and was not significantly different when co-exposed to WSF. Exposure to AgNPs alone caused increases in gene expressions of GST and SOD, whereas WSF exposure caused an induction in SOD. Responses in enzyme activities were generally low, with significant effects observed only on SOD activity in NPL and WSF exposures and on GST activity in NPL and NPH exposures. Combined AgNP and WSF exposures caused slightly altered responses in expression of SOD, GST and CYP330A1 genes compared to the single exposures of either AgNPs or WSF. However, there was no clear pattern of cumulative effects caused by co-exposures of AgNPs and WSF. The present study indicates that the exposure to AgNPs, Ag+, and to a lesser degree WSF cause an oxidative stress response in C. finmarchicus, which was slightly, but mostly not significantly altered in combined exposures. This indicated that the combined effects between Ag and WSF are relatively limited, at least with regard to oxidative stress.

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.

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 estuarine meiofauna: A microcosm approach

Although soluble hydrocarbons persist for only hours to days in aquatic environments, they potentially pose a high toxicity to aquatic biota. Here we investigate effects of the water-soluble fraction (WSF) of crude oil on estuarine meiofauna, with special focus on nematodes. Copepods and amphipods were the most sensitive taxa, disappearing almost completely within 3 weeks after exposure. In nematodes, we observed mostly sublethal short-term effects of WSF, such as changes in feeding-type composition and age structure. In the longer term (months), total nematode density and species composition were significantly affected, whereas different diversity indices did not exhibit significant responses. Deposit-feeding and predatory nematodes were the most affected feeding types. Nevertheless, sensitivity was species-specific, with sometimes opposing responses between even congeneric species. Our results demonstrate the need to assess WSF effects on communities at the species level and over time periods well exceeding the residence time of the WSF in the environment.

Water-soluble fraction of crude oil affects variability and has transgenerational effects in Daphnia magna

The importance of interindividual variability in environmental responses has been little studied, although the available information suggests that, e.g., changes in environmental temperature may be associated with changes in variability. We studied, if exposure to water-soluble fraction (WSF) of crude oil can be associated with changes in interindividual variability in phenotype in Daphnia magna, which reproduces parthenogenetically. By using these clonal organisms, we could exclude the possibility that the observed changes were caused by genetic variability. The results show that the variability of oxygen consumption rate decreased in 48 h 30% WSF-exposed animals as compared to 10% WSF-exposed or control animals without a change in the mean of oxygen consumption rate. The clonal Daphnia magna could also be used to study transgenerational effects without genetic contribution, as the different generations are genetically identical. We observed that the oxygen consumption rates in F1 and F2 generations of unexposed and 10% WSF-exposed Daphnia had decreased from parental F0 generation and were also lower than in offspring of 30% WSF-exposed specimens. The studies did not aim at environmental realism but were designed to show the possibility of variability changes without changes in the mean value of a parameter, and transgenerational effects as a result of environmental contamination.

Mortality of embryos, developmental disorders and changes in biochemical parameters in marsh frog (Rana ridibunda) tadpoles exposed to the water-soluble fraction of Kazakhstan crude oil and O-Xylene

ABSTRACTThe effects of different concentrations of water-soluble fraction of crude oil (WSFO) from the Zhanazhol oil field (Aktobe region, Kazakhstan) and compared to o-xylene, prevalent in this oil, on growth and development of marsh frog (Rana ridibunda) were assessed. In subchronic experiments (7 d), a dose-related increase in mortality and incidence of deformities in embryos were observed. In chronic experiments (60 d; starting from the Gosner stage 26), a dose-dependent decrease in body weight, size and developmental delay by 3–4 stages were also detected. In addition, the content of lipid hyperoxide (LHO) and malondialdehyde (MDA), as well as activities of superoxide dismutase (SOD) and catalase (CAT) enzymes in liver of the tadpoles were determined at the end of chronic experiment. Exposure to 0.5 mg/L or 1.5 mg/L WSFO elevated the content of LHO by 76% and 86%, and MDA by 47% and 58% but decreased SOD activity by 26% and 49%, and CAT by 35% and 46%, respectively. A less pronounced adverse effect was found after chronic exposure to the same concentrations of o-xylene. In tadpole liver exposed to o-xylene levels of LHO was increased by 40% and 51%, MDA by 11% and 29%, while the activity of SOD was lowered by 18% and 41%, and CAT – by 13% and 37% in the 0.5 mg/L and 1.5 mg/L treatment groups, respectively. Data demonstrated the embryotoxic and teratogenic effects attributed to WSFO and o-xylene exposure which may involve oxidative stress mechanisms.

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.

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.

Crude oil at concentrations considered safe promotes rapid stress-response in Lake Baikal endemic amphipods

The current study evaluated the possible toxic effects of the water-soluble fraction of crude oil on the general cellular stress-response mechanisms of two dominant representatives of Lake Baikal’s littoral community, the endemic amphipod species Eulimnogammarus verrucosus and E. cyaneus. The acute toxicity effects on the cellular stress-response mechanisms of amphipods were studied in the laboratory by exposing amphipods in water from Lake Baikal to addition of a water-soluble fraction of crude oil at concentrations considered safe for the aquatic environment. The present study found that even short-term exposure to a water-soluble fraction of crude oil at concentration of 50 µg/L, established as the threshold limit for fishery and aquaculture water reservoirs in the Russian Federation, directly affected the general stress-response markers HSP70 and lipid peroxidation and significantly changed the activity of antioxidant enzymes in both studied species. This result confirms the high sensitivity of Baikal endemics to crude oil. Thus, it also indicates that established standards and threshold limit values of oil concentrations estimated for ecological monitoring of general water reservoirs cannot be applied directly to the unique Lake Baikal ecosystem.

Toxic Effects of Water Soluble Fractions of Crude Oil, Diesel and Gasoline on Ceratophyllum Demersum

Abstract- Oil exploration and exploitation has resulted in oil pollution in the Niger Delta. This study investigated the toxicity of water soluble fractions (WSFs) of crude oil, diesel fuel and gasoline on Ceratophyllum demersum (L). The parameters measured include fresh weight, biomass production and relative growth rate. The water soluble fractions concentrations used were 25%, 50% 100% for crude oil and diesel and 5%, 10%, 20% were used for gasoline. Results from the study showed that at 25% WSF of crude oil and diesel fuel and 5% WSF of gasoline, there was significant increase (P &lt; 0.05) in fresh weight, biomass production and relative growth rate of Ceratophyllum demersum. While increase in concentration resulted in decrease in the growth parameters. High concentrations of Water Soluble Fractions of gasoline were the most toxic followed by diesel fuel. This study showed that low concentration of water soluble fractions of petroleum hydrocarbons enhanced growth while high concentration was toxic to the aquatic macrophyte. &#x0D; Keywords: Crude oil, diesel, gasoline, Ceratophyllum demersum.

The use of rockfish Sebastiscus marmoratus as a sentinel species to assess petroleum hydrocarbons pollution: A case study in Quanzhou Bay, China

To monitor the biological effects of marine pollution, choosing a native fish species and establishing suitable biomarkers are required. In this study, the full-length cDNA of cyp1a1 was cloned from Sebastiscus marmoratus (SM-CYP1A1). Then the dose-response and time-course induction of hepatic CYP1A1 mRNA by the crude oil water-soluble fraction (WSF) were determined. Subsequently, SM-CYP1A1 mRNA was applied to investigate the biological effect of petroleum hydrocarbon pollution in Quanzhou Bay, China. The transcription levels of hepatic CYP1A1 were significantly elevated in fish caged in the polluted sites for 2weeks compared with those of the reference site, which were correlated with the concentrations of petroleum hydrocarbon and polycyclic aromatic hydrocarbon (PAH) in the surface seawaters. The results suggest that S. marmoratus is a potential sentinel organism to monitor marine pollutants and the hepatic CYP1A1 mRNA can serve as a sensitive biomarker to organic xenobiotics in aquatic environments.

Early life stages of an arctic keystone species (Boreogadus saida) show high sensitivity to a water-soluble fraction of crude oil

Increasing anthropogenic activities in the Arctic represent an enhanced threat for oil pollution in a marine environment that is already at risk from climate warming. In particular, this applies to species with free-living pelagic larvae that aggregate in surface waters and under the sea ice where hydrocarbons are likely to remain for extended periods of time due to low temperatures. We exposed the positively buoyant eggs of polar cod (Boreogadus saida), an arctic keystone species, to realistic concentrations of a crude oil water-soluble fraction (WSF), mimicking exposure of eggs aggregating under the ice to oil WSF leaking from brine channels following encapsulation in ice. Total hydrocarbon and polycyclic aromatic hydrocarbon levels were in the ng/L range, with most exposure concentrations below the limits of detection throughout the experiment for all treatments. The proportion of viable, free-swimming larvae decreased significantly with dose and showed increases in the incidence and severity of spine curvature, yolk sac alterations and a reduction in spine length. These effects are expected to compromise the motility, feeding capacity, and predator avoidance during critical early life stages for this important species. Our results imply that the viability and fitness of polar cod early life stages is significantly reduced when exposed to extremely low and environmentally realistic levels of aqueous hydrocarbons, which may have important implications for arctic food web dynamics and ecosystem functioning.

Effect of Crude Oil Water Soluble Fraction Toxicity on Tilapia Guineensis Fingerlings Using Histology of the Kidney as a Bioassay Indicator

Histological studies is well established as a fundamental relationships between pollutants and exposure to living organisms. The various biological responses and changes observed with such histological alterations can be used as a tool to detect toxic effects of pollutants in the organs of living organism making it a good environmental stressor indicator for bioassay. Tilapia guineensis fingerlings were collected at acute toxcity and after 98 days recovery period. Bonny-light crude oil (BLCO) and Benin River crude oil (BRCO) Water soluable fraction (WSF) were used as pollutant with different concentration from 0.00, 0.25%, 0.55%, 0.85% and 1.25% for acute toxicity and recovery period. The kidney tissue samples of the fish at acute toxicity (4 days) and recovery period (98 days) was collected for different WSF concentration, fixed, and sectioned. The histological sections of 5μg thickness of each sample were prepared and fixed on slide. This was observed (M x 400) under a light microscope (Olympus Model QC pass 02) linked to ACER LCD monitor with an Integrated Digital Scope photo (Model DCM 35). The experiment showed that crude oil water soluble fraction (WSF) as a the pollutant resulted in cytoplasmic vascuolation of the epithelial cells, leading to degeneration of the cytoplasm and enlarged tubule of the kidney of Tilapia guineensis fingerlings for both BLCO and BRCO as concentration increased. The 98 days recovery period showed larger increase in cytoplasmic vacuolization of the kidney cytoplasm tissue for both crude oil WSF. The effect of Bonny-light and Benin River crude oil on the kidney of Tilapia guineensis showed true reflection of effect of pollution with swelling of the renal tubules. The response of the kidney tissue of Tilapia guineensis as observed in this work is an indication that Tilapia guineensis is a good candidate for bioassay test serving as a pollution indcator species.