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Potential biodegradation of crude petroleum oil by newly isolated halotolerant microbial strains from polluted Red Sea area Полный текст
2016
Shetaia, Yousseria M.H. | El khalik, Wafaa A.A. | Mohamed, Tarek M. | Farahat, Laila A. | ElMekawy, Ahmed
Two microbial isolates from oil polluted Red Sea water in Egypt, designated as RS-Y1 and RS-F3, were found capable of degrading Belayim mix (BX) crude oil. Strains RS-Y1 and RS-F3 were assigned to the genera Lipomyces tetrasporus and Paecilomyces variotii based on their morphological and physiological characteristics. Both isolates were compared for the biodegradation of crude petroleum-oil hydrocarbons in basal salt medium supplemented with 5% (w/v) of BX-crude oil. Gas chromatography profile showed that the biodegradation of total petroleum hydrocarbons (TPHs) inoculated with L. tetrasporus (68.3%) and P. variotii (58.15%) along with their consortium (66%) significantly reduced TPHs levels as compared to the control after 30days. L. tetrasporus (44.5%) was more effective than P. variotii strain (32.89%) in reducing the unresolved complex mixtures (UCM) content from the medium. Both isolates exhibited a strong growth over a wide range of salinity (5–45g/L NaCl).
Показать больше [+] Меньше [-]Determination of microcystin-LR in clams (Tapes decussatus) of two Sardinian coastal ponds (Italy) Полный текст
2016
Sedda, Tiziana | Baralla, Elena | Varoni, Maria Vittoria | Pasciu, Valeria | Lorenzoni, Giuseppa | Demontis, Maria Piera
The presence of microcystin-LR (MC-LR) was monitored in Tapes decussatus harvested in two Sardinian ponds (Cabras and Tortolì, Italy) in spring and summer. After solid phase extraction, samples were analyzed using a screening enzyme-linked immunosorbent assay (ELISA) followed by a liquid chromatographic coupled to tandem mass spectrometer (LC–MS/MS) analysis. Results obtained through the ELISA test showed the presence of microcystins with a maximum concentration in August for Cabras pond (0.55ng/g) and in September for Tortolì pond (0.85ng/g). The LC–MS/MS analysis did not confirm the presence of MC-LR suggesting that results obtained with the ELISA technique could be due to the presence of other microcystins. According to the tolerable daily intake suggested by the World Health Organization, these results hint that clams harvested in these ponds are safe for human health. These data can contribute to enrich the knowledge about the healthiness of Sardinian ponds and of their products.
Показать больше [+] Меньше [-]Polychlorinated naphthalenes in the air over the equatorial Indian Ocean: Occurrence, potential sources, and toxicity Полный текст
2016
Huang, Yumei | Li, Jun | Xu, Yue | Xu, Weihai | Zhong, Guangcai | Liu, Xiang | Zhang, Gan
Monitoring of marine polychlorinated naphthalenes (PCNs) is crucial, as they are considered persistent organic pollutants (POPs) by the Stockholm Convention. Data on PCNs in marine environment are scarce. In this study, 19 air samples were collected during a cruise in the equatorial Indian Ocean on board the Chinese research vessel Shiyan I from 4/2011 to 5/2011. PCN concentration of these air samples ranged from 0.033 to 2.56pgm−3, with an average of 0.518pgm−3, equal to or lower than the values reported for other oceans, seas, and lakes worldwide. Tri- and tetra-CNs were the main homologues in most samples. Reemission of Halowax mixtures and incineration processes were the major sources of atmospheric PCNs in the study area. The PCN-corresponding toxic equivalency values ranged from 0 to 0.190fgm−3 (average: 0.038fgm−3), falling in the low end of global range.
Показать больше [+] Меньше [-]Temporal scales for nearshore hits of current-driven pollution in the Gulf of Finland Полный текст
2016
Lagrangian trajectories of water parcels reconstructed using the TRACMASS model from three-dimensional velocity fields by the RCO model for 1965–2004 are used to analyse the temporal scales and the probability for the hits to the nearshore by pollution originating from a major fairway in the Gulf of Finland and transported by surface currents. Increasing the simulation length from 10 to 20days induces a linear increase in particle age, but the pattern of nearshore hits remains the same. A reasonable benefit can be reached by relatively small shifts of certain parts of the present fairway in a few locations. The overall probabilities do not reveal any trend for 1965–2004. The largest changes in the nearshore hits are revealed for the proportion of hits to the opposite nearshore areas. This feature probably reflects an abrupt turn of the geostrophic air-flow over the southern Baltic Sea by ~40° since 1987.
Показать больше [+] Меньше [-]Realistic environmental mixtures of hydrophobic compounds do not alter growth of a marine diatom Полный текст
2016
In this paper we determine whether a realistic mixture of hydrophobic chemicals affects the growth dynamics of a marine diatom and how this effect compares to the effect of temperature, light regime and nutrient conditions. To do so, we examine the specific growth rate of Phaeodactylum tricornutum in a 72h algal growth inhibition test using a full factorial design with three nutrient regimes, two test temperatures, three light intensities and three chemical exposures. Passive samplers were used to achieve exposure to realistic mixtures of organic chemicals close to ambient concentrations. Nutrient regime, temperature and time interval (24, 48 and 72h) explained 85% of the observed variability in the experimental data. The variability explained by chemical exposure was about 1%. Overall, ambient concentrations of hydrophobic compounds present in Belgian coastal waters, and for which the passive samplers have affinity, are too low to affect the intrinsic growth rate of P. tricornutum.
Показать больше [+] Меньше [-]Behavior of suspended particles in the Changjiang Estuary: Size distribution and trace metal contamination Полный текст
2016
Yao, Qingzhen | Wang, Xiaojing | Jian, Huimin | Chen, Hongtao | Yu, Zhigang
Suspended particulate matter (SPM) samples were collected along a salinity gradient in the Changjiang Estuary in June 2011. A custom-built water elutriation apparatus was used to separate the suspended sediments into five size fractions. The results indicated that Cr and Pb originated from natural weathering processes, whereas Cu, Zn, and Cd originated from other sources. The distribution of most trace metals in different particle sizes increased with decreasing particle size. The contents of Fe/Mn and organic matter were confirmed to play an important role in increasing the level of heavy metal contents. The Cu, Pb, Zn, and Cd contents varied significantly with increasing salinity in the medium–low salinity region, thus indicating the release of Cu, Pb, Zn, and Cd particles. Thus, the transfer of polluted fine particles into the open sea is probably accompanied by release of pollutants into the dissolved compartment, thereby amplifying the potential harmful effects to marine organisms.
Показать больше [+] Меньше [-]Assessment of natural radioactivity and 137Cs in some coastal areas of the Saudi Arabian gulf Полный текст
2016
Al-Ghamdi, H. | Al-Muqrin, A. | El-Sharkawy, A.
The levels of natural radioactivity have been investigated in some Saudi Arabian Gulf coastal areas. Sampling sites were chosen according to the presence of nearby non-nuclear industrial activities such as, the two main water desalination plants in Al Khobar and Al Jubail, and Maaden phosphate complex in Ras Al Khair, to ensure that effluents discharges into the Arabian Gulf didn't enhance radioactivity in seawater and shore sediments. Seawater samples were analyzed for radium isotopes (Ra-226 & Ra-228) and measured by gamma spectrometry using high purity germanium detector, after radiochemical separation of the isotopes by co-precipitation with MnO2. Shore sediment samples were analyzed for 226Ra, 228Ra (232Th), 4°K and 137Cs using gamma sepectrometry. A small variation was observed in the activity concentrations of the investigated radioisotopes, and the activity levels were comparable to those reported in literature. Quality assurance and methods validation were established through the efficiency calibration of the detectors, the estimation of uncertainties, the use of blanks, the analysis of standard reference materials and the intercomparison and proficiency tests. Radiological hazards were assessed, and the annual effective dose had an average value of 0.02mSv. On the basis of the current results, we may conclude that any radiological hazards to the public visiting these shores are not expected.
Показать больше [+] Меньше [-]Oil species identification technique developed by Gabor wavelet analysis and support vector machine based on concentration-synchronous-matrix-fluorescence spectroscopy Полный текст
2016
Wang, Chunyan | Shi, Xiaofeng | Li, Wendong | Wang, Lin | Zhang, Jinliang | Yang, Chun | Wang, Zhendi
Concentration-synchronous-matrix-fluorescence (CSMF) spectroscopy was applied to discriminate the oil species by characterizing the concentration dependent fluorescence properties of petroleum related samples. Seven days weathering experiment of 3 crude oil samples from the Bohai Sea platforms of China was carried out under controlled laboratory conditions and showed that weathering had no significant effect on the CSMF spectra. While different feature extraction methods, such as PCA, PLS and Gabor wavelet analysis, were applied to extract discriminative patterns from CSMF spectra, classifications were made via SVM to compare their respective performance of oil species recognition. Ideal correct rates of oil species recognition of 100% for the different types of oil spill samples and 92% for the closely-related source oil samples were achieved by combining Gabor wavelet with SVM, which indicated its advantages to be developed to a rapid, cost-effective, and accurate forensic oil spill identification technique.
Показать больше [+] Меньше [-]Trends and drivers of debris accumulation on Maui shorelines: Implications for local mitigation strategies Полный текст
2016
Blickley, Lauren C. | Currie, Jens J. | Kaufman, Gregory D.
Marine debris, particularly plastic, is an identified concern for coastal areas and is known to accumulate in large quantities in the North Pacific. Here we present results from the first study to quantify and compare the types and amounts of marine debris on Maui shorelines. Surveys were conducted monthly between May 2013 and December 2014, with additional daily surveys conducted on Maui's north shore during January 2015. Debris accumulation rates, loads, and sources varied between sites, with plastics being the most prevalent type of debris at all sites. Large debris loads on windward shores were attributed to the influence of the North Pacific Subtropical Gyre and northerly trade winds. Daily surveys resulted in a significantly higher rate of debris deposition than monthly surveys. The efficacy of local policy in debris mitigation showed promise, but was dependent upon the level of enforcement and consumer responsibility.
Показать больше [+] Меньше [-]Fishes as indicators of untreated sewage contamination in a Mexican coastal lagoon Полный текст
2016
Aguilar-Betancourt, Consuelo M. | González Sansón, Gaspar | Kidd, Karen A. | Munkittrick, Kelly R. | Curry, R Allen | Kosonoy-Aceves, Daniel | Lucano-Ramírez, Gabriela | Ruiz-Ramírez, Salvador | Flores-Ortega, Juan R.
Lagoons are important nursery habitats for fishes but are often sites of intense human activity including wastewater discharges. The goal of this research was to compare stable nitrogen (δ15N) and carbon (δ13C) isotopes, total mercury (THg) and other metal levels in four selected fish species among sites with different levels of untreated sewage discharge inside Barra de Navidad coastal lagoon in the Mexican Pacific. Three species from sites heavily impacted by sewage showed higher δ15N and δ13C compared to those from non-impacted sites. In addition, the highest concentrations of THg were present in fish of two species (Sciades guatemalensis and Diapterus brevirostris) collected at the two most impacted sites, and exceeded the 0.2μg/g ww threshold believed to be protective of adult and juvenile fish. No individuals of Achirus mazatlanus and Mugil curema exceeded this threshold, and liver somatic index and condition did not distinguish high from low impacted sites for all species. In general, the metal levels differed among species but not sites, and were lower than what has been measured in fishes elsewhere. The study also provides the first information on several fish species for coastal areas of Mexico, suggests that THg and isotopes can distinguish sewage-impacted sites, and can serve as a baseline for future studies.
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