Distribution, source and ecological risk assessment of polycyclic aromatic hydrocarbons in the sediments of northern part of the Persian Gulf.

Distribution, sources, and ecological risk of 43 compounds of polycyclic aromatic hydrocarbons (PAHs) in surficial sediments of the Persian Gulf were investigated. The sediments were sampled from 60 offshore stations during an oceanographic cruise in the winter of 2012. Gas chromatography high-resolution mass spectrometry was used for the PAHs determinations in sediment samples. The concentrations of 21 parent PAHs, 7 methylated PAHs, 11 oxygenated PAHs and 4 nitrated PAHs were 9.0-201.5 ng g-1 dw, 3.3-60.3 ng g-1 dw, 15.2-172.7 ng g-1 dw and 0.1-8.3 ng g-1 dw, respectively. Among 21 parental PAHs, naphthalene (29.35 ng g-1 dw), phenanthrene (4.6 ng g-1 dw), and pyrene (3.18 ng g-1 dw) were the most abundant compound. 1-acenaphthenone (43.41 ng g-1 dw) and 2-methylnaphthalene (7.15 ng g-1 dw) showed the highest concentration in the oxy- and methyl-PAHs, respectively. The concentrations of nitro-PAHs were between not detected to 4 ng g-1 dw. According to the ecological risk assessment, the calculated total toxicity of PAHs was at below the lethal level on benthic organisms in all stations in the Persian Gulf, but there is risk of toxicity for the benthic organism in the Gulf of Oman (from the Strait of Hormuz to Jask). In general, nitrogenated and oxygenated derivatives did not show a significant risk in the study area. Based on the diagnostic ratios, the mixed sources (both petrogenic and pyrogenic) and pyrogenic sources have been identified for PAHs. Biomass combustion source has been identified for the stations near flares and gas fields. Principle component analysis-multivariate linear regression analysis for source identification shows that maritime traffic, abundant flares that burn the gas in oil, gas fields and dust storms have a major impact on the production of PAHs in this area.

Assessment of oxidative stress response genes in Avicennia marina exposed to oil contamination - Polyphenol oxidase (PPOA) as a biomarker.

Mangrove plants, which inhabit and form sensitive ecosystems in the intertidal zones of tropical and subtropical coastlines, though vulnerable to petroleum pollution, still maintain their growth under oil contamination. To elucidate the molecular response of mangrove plants to crude oil-sediment mixture, seeds of Avicennia marina were planted and grown on 0, 2.5, 5.0, 7.5 and10 % (w/w) oil-contaminated soil. Plant biomass was highly affected from 3.05 ± 0.28 (Control) to 0.50 ± .07 (10 %) and from 3.47 ± 0.12 to 1.88 ± 0.08 in 2 and 4 months old plants respectively. The expression analysis of 11genes belonging to detoxification pathways in the roots and leaves of 2 and 4 month-old plants was evaluated by qRT-PCR. Our results showed changes in expression levels of Fe-SOD, Mn-SOD, CAT, PRX, PPOs, GSTs, and NAP2 whose products are involved in reactive oxygen species (ROS) and xenobiotic detoxification. PPOA showed the highest expression induction of 43 ± 1.15, followed by CAT (12.61 ± 3.25) and PPOB (6.38 ± 1.34) in leaves of 2 months old seedlings grown on 7.5, 10 and 7.5 % oil contaminated soil respectively. PPOA (39.23 ± 2.1), PRX (32.13 ± 1.2) as well as PPOB (26.11 ± 1.3) showed the highest expression induction in leaves of 4 months old plants grown in 2.5 % oil contaminated soil. Our data indicated that PPOA can be a good biomarker candidate gene for long term exposure to oil contamination in A. marina.

The effect of the water soluble fraction of crude oil on survival, physiology and behaviour of Caspian roach, Rutilus caspicus (Yakovlev, 1870).

The water soluble fraction (WSF) of crude oil is a complex and toxic mixture of hydrocarbons that aquatic organisms directly encounter in oil spills. WSF plays an important role in the toxicity of crude oil to aquatic organisms. In the present study, the effects of WSF on juvenile Caspian roach, Rutilus caspicus, at lethal and sub-lethal level was investigated. The lethality of WSF on R. caspicus was studied by conducting 96h LC50 tests with semi-static exposure methods with 6 and 24h solution renewals. The 96h LC50 of WSF was estimated at 62.5% and 35.9% WSF concentrations for 24h and 6h renewal methods, respectively. To investigate the sub-lethal effect of WSF on R. caspicus, fish were exposed to 62.5, 31.3, and 6.3% concentrations of WSF for 24h and changes in their respiration rate and swimming activity was monitored during the exposure. At the end of the exposure period, four hematologic parameters [O2 and CO2 pressures (pO2 and pCO2), hematocrit, and hemoglobin content] of the fish were measured. The result of the behavioural experiment revealed that all three studied concentrations of WSF elevated the respiration rate and reduced the swimming activity of R. caspicus. No significant changes were detected in the hematocrit and hemoglobin content of the fish blood, but the blood pO2 of the fish exposed to 62.5% WSF decreased while the blood pCO2 increased. The results of this study suggest that the egression of the volatile components in hydrocarbon mixtures during conventional semi-static toxicity tests may lead to underestimating the toxicity of the hydrocarbons. The results of the sub-lethal experiments propose that failure of the respiratory system that leads to asphyxia may be a major mechanism that results in lethal effect of WSF in high concentrations.

The effect of sublethal concentrations of the water-soluble fraction of crude oil on the chemosensory function of Caspian roach, Rutilus caspicus (YAKOVLEV, 1870).

The water-soluble fraction of crude oil is a complex and toxic mixture of hydrocarbons. Because aquatic organisms directly encounter it, the water-soluble fraction plays an important role in the toxicity of crude oil in aquatic environments. To determine whether fish are attracted to or avoid the water-soluble fraction, Caspian roaches (Rutilus caspicus) were exposed to different concentrations of the water-soluble fraction in a choice maze apparatus. The results showed that Caspian roaches can detect and avoid 2 mg/L of the water-soluble fraction. To study the effect of the water-soluble fraction on the olfactory function of fish, Caspian roaches were exposed to 3.2 mg/L and 16 mg/L of the water-soluble fraction for 96 h; afterward, exposed fish encountered food extract in a choice maze apparatus. The present study showed that the water-soluble fraction significantly impairs the olfactory function of roaches. To investigate the effect of olfactory system dysfunction on the feeding behavior of fish, Caspian roaches were exposed to 3.2 mg/L and 16 mg/L of the water-soluble fraction. After 4 d, 8 d, and 12 d of exposure, the feeding behavior toward the food extract was tested. The results showed that both 3.2 mg/L and 16 mg/L of the water-soluble fraction suppress the feeding behavior of Caspian roaches. The present study demonstrates that sublethal concentrations of crude oil's water-soluble fraction impair the olfactory function of fish and consequently suppress the feeding behavior.

Comparison of inducible nitric oxide synthase activity in pancreatic islets of young and aged rats.

OBJECTIVES: Some pathologic situations such as diabetes and metabolic syndrome are associated with alternation in nitric oxide level. Incidence of these condition increases with aging. On the other hand, insulin secretion is modulated by nitric oxide, and nitric oxide synthase (NOS) activity is also altered in diabetes. In this study, modification in the enzyme activity associated with aging and also optimized procedure for islet NOS assay was investigated. MATERIALS AND METHODS: Male Wistar rats were randomly divided in two experimental groups: A: adult rats; were 4 month old and B: old rats; were 12 month old. In all groups, plasma glucose, insulin and NOX (nitrite + nitrate = NOX) were measured, and also insulin secretion in isolated pancreatic islet with or without L-NAME was investigated. Furthermore, the inducible NOS activity with L-citrulline measurement in islets was measured. RESULTS: L-citrulline was quantified using one step HPLC column. Aging induced hyperglycemia (P<0.05) and excess plasma NOX (17.74 ± 1.664 and 26.25 ± 2.166 µmol/l in A and B groups respectively, P<0.05) with unaltered plasma insulin. Islet insulin secretion was significantly reduced in aging rats. L-NAME induced islet insulin secretion especially in aging rats (P=0.003). Inducible NOS activity in islets of aging rats was significantly higher than adult rats (1.082 ± 0.084 and 6.277 ± 0.475 pmol/min per mg protein in adult and aging rats, respectively, P<0.001). CONCLUSION: These findings show that decreased in islet insulin secretion may be related to increase in iNOS activity in islets, which follows impaired carbohydrate metabolism in aging.

Biodegradation of polycyclic aromatic hydrocarbons by a bacterial consortium enriched from mangrove sediments.

Polycyclic aromatic hydrocarbons (PAHs) biodegradation in contaminated sediment is an attractive remediation technique and its success depends on the optimal condition for the PAH-degrading isolates. The aims of the current study was to isolate and identify PAHs-degrading bacteria from surface sediments of Nayband Bay and to evaluate the efficiency of statistically based experimental design for the optimization of phenanthrene (Phe) and Fluorene (Flu) biodegradation performed by enriched consortium. PAHs degrading bacteria were isolated from surface sediments. Purified strains were then identified by 16S rDNA gene sequence analysis. Taguchi L16 (4(5)) was employed to evaluate the optimum biodegradation of Phe and Flu by the enriched consortium. Total of six gram-negative bacterial strains including Marinobacter hydrocarbonoclasticus, Roseovarius pacificus, Pseudidiomarina sediminum and 3 unidentified strains were isolated from enrichment consortium, using Fluorene (Flu) and phenanthrene (Phe) as the sole carbon and energy source. The enriched consortium showed highest degradation abilities (64.0% Flu and 58.4% Phe degraded in 7 days) in comparison to a single strain cultures or mixtures. Maximum biodegradation efficiency was occur at temperature = 35°C; pH = 8; inoculum size = 0. 4 OD600nm; salinity = 40 ppt; C/N ratio = 100:10. In conclusion our results showed that, indigenous bacteria from mangrove surface sediments of Nayband Bay have high potential to degrade Flu and Phe with the best results achieved when enriched consortium was used.

Analysis of Anabaena vaginicola and Nostoc calcicola from Northern Iran, as rich sources of major carotenoids.

Four major carotenoids of high nutritional significance, including ß-carotene, lycopene, lutein and zeaxanthin were determined in three isolates of heterocystous cyanobacteria, belonging to the genera Anabaena and Nostoc, isolated from Iranian terrestrial and aquatic ecosystems, for the first time. The ultrasonically extracted carotenoids were identified and quantified by a rapid and sensitive isocratic HPLC method and identification was further confirmed by spiking authentic standards and the pattern of the UV-Vis spectra obtained from photo-diode array detector. The results showed that these isolates contain large amounts of four major carotenoids, especially lycopene (up to 24,570 µg/g dry weight, DW) which appears to be the highest reported amount until present; and ß-carotene (up to 8133 µg/g DW) which is comparable with the best natural sources of ß-carotene. Meanwhile, they are rich in the cis-isomers of lycopene and ß-carotene which is important in their bioavailability and health benefits.

Selective adsorption of 2,4-dinitrophenol on molecularly imprinted nanocomposites of mesoporous silica SBA-15/polyaniline.

Surface imprinting and adoption of a nano-sized physical form are two effective approaches to overcome the template transfer difficulty within molecularly imprinted polymers (MIPs). This work is an attempt to conquer the problem of template transfer difficulty within MIPs by using a nano-reactor as a substrate for the reaction between the monomer and the template. Negatively charged hexagonal nano-channels of SBA-15 can act as a support for attachment of positively charged aniline monomers and the 2,4-dinitrophenol (2,4-DNP) template. The imprinted and non-imprinted SBA-15/polyaniline nanocomposites were characterized by Fourier transform infrared (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and nitrogen adsorption-desorption isotherms. The results showed that the synthesized polymer possessed a highly ordered mesoporous structure. The distribution coefficient values of 2,4-DNP, K(d (2,4-DNP)), were estimated as 301.4 ± 2.3 and 101.2 ± 1.0 mL g(-1) for imprinted and non-imprinted polymers (NIP), respectively. The MIP-solid-phase extraction (SPE) process was optimized by evaluating the type of washing solvent and the composition and volume of the eluting solvent. The prepared MIP was used as a selective sorbent for SPE of 2,4-DNP in the presence of phenolic compounds in tap and sea water. The experimental results indicated that the MIP-SPE and NIP-SPE column yielded recoveries higher than 96% and 38%, respectively. The R.S.D. values were also lower than 3.2% and 4.6% for MIP-SPE and NIP-SPE, respectively.