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Effects of weathering process on the stable carbon isotope compositions of polycyclic aromatic hydrocarbons of fuel oils and crude oils
2018
Li, Ying | Liu, Yu | Jiang, Dawei | Xu, Jixiang | Zhao, Xinda | Hou, Yongchao
Two fuel oils and two crude oils were subjected to a 60-day weathering simulation experiment, and the effects of weathering on some common parameters for aromatics and aromatic δ¹³C values were studied. The results show that weathering of all oil samples affected little the DBT/P (dibenzothiophene/phenanthrene) ratio and methylphenanthrene distribution fraction. Four oil samples could be distinguished only by the DBT/P ratio. The effect of weathering on isotopes in polycyclic aromatic hydrocarbons was small. The results show that the types of four oil samples can be distinguished, while Kuwait and Russia crude oils cannot be discriminated from each other totally by double-coordinate two-dimensional maps for aromatic δ¹³C; all of the oil samples can be distinguished by principal component analysis of δ¹³C for aromatics, the relationship of DBT/P and PAHs δ¹³C values. Therefore, the δ¹³C value of aromatics can be used as an alternative index for the analysis of oil spills.
显示更多 [+] 显示较少 [-]Concentrations of selected radionuclides and their spatial distribution in marine sediments from the northwestern Gulf, Kuwait
2018
Uddin, Saif | Behbehani, Montaha
This study focuses on creating a baseline for ⁴⁰K, ²¹⁰Pb, ¹³⁷Cs, ⁹⁰Sr, ²²⁶Ra, ²²⁸Ra, ²³⁸U, ²³⁵U, ²³⁴U, ²³⁹⁺²⁴⁰Pu and ²³⁸Pu in marine sediments in the northwestern Gulf. The respective measured concentration ranges were 386–489, 32.3–48.8, 1.5–2.9, 4.53–5.42, 18.3–23.1, 18.8–23.0, 22.3–30.5, 0.99–1.33, 25.6–34.8, 0.30–0.93, and 0.0008–0.00018Bqkg⁻¹. The levels of these radionuclides are generally comparable to values reported for other marine waters in the northern hemisphere. The ¹³⁷Cs activity in the Gulf sediments offshore Kuwait is an order of magnitude lower compared to sediments from northeastern Iran. Other than that finding, no hot spots were observed in sediments adjacent to power and desalination plants, oil and gas industrial activities or wastewater treatment facilities. These data will serve as a baseline to gauge possible future inputs of radionuclides in the northern Gulf. The calculated average ratio of ²³⁵U/²³⁸U activity in the area is in agreement with the reported figure of the natural uranium ratio, suggesting the absence of depleted uranium (DU) at all the stations. The low concentration of ²³⁹⁺²⁴⁰Pu suggests that there is no significant source of plutonium except that from atmospheric fallout from weapon testing and possible dry deposition via long-range dust transport.
显示更多 [+] 显示较少 [-]Environmental characterization of a semiarid hyper saline system based on dissolved trace metal-macronutrient synergy: A multivariate spatio-temporal approach
2018
Al-Said, Turki | Madhusoodhanan, Rakhesh | Pokavanich, Tanuspong | Al-Yamani, Faiza | Kedila, Raziya | Al-Ghunaim, Aws | Al-Hashem, Ali
Trace metals and macronutrients play key roles in marine biogeochemical processes. Despite their higher availability, no reliable information is available on their ecological role in the hypersaline waters of NW Arabian Gulf. The present study identifies their synergistic effect on environmental characteristics and autotrophic biomass in the shallow coastal and offshore waters, off Kuwait on a seasonal basis. Surface water samples collected along four predefined transects were analyzed for physico-chemical and biological variables during summer (n=27) and winter (n=27) seasons. Multivariate analyses revealed clear spatial and seasonal trends, and identified the best suit of environmental variables responsible for the seasonal variability in phytoplankton biomass. Using statistically derived supply to demand ratios, carbon-trace metal stoichiometry, and bioavailability of trace metals, we propose possible growth regulating factors for phytoplankton on a seasonal basis in the NW Arabian Gulf, off Kuwait. This is the first report on trace metals from the entire Arabian Gulf, using clean techniques and multivariate statistical approach.
显示更多 [+] 显示较少 [-]High total organic carbon in surface waters of the northern Arabian Gulf: Implications for the oxygen minimum zone of the Arabian Sea
2018
Al-Said, Turki | Naqvi, S.W.A. | Al-Yamani, Faiza | Goncharov, Alexandr | Fernandes, Loreta
Measurements of total organic carbon (TOC) for two years in Kuwaiti waters showed high TOC levels (101.0–318.4, mean 161.2 μM) with maximal concentrations occurring within the polluted Kuwait Bay and decreasing offshore, indicating substantial anthropogenic component. Analysis of winter-time data revealed a large increase in density over the past four decades due to decrease in Shatt Al-Arab runoff, implying that the dissolved/suspended organic matter in surface waters of the northern Gulf could be quickly injected into the Gulf Deep Water (GDW). Our measurements together with an analysis of previously collected/published data suggest that the recent summer-time declining trend in oxygen in the GDW might be related to eutrophication. Higher preformed TOC and lower preformed dissolved oxygen contents of the high-salinity water mass that flows out of the Gulf and ventilates the mesopelagic oxygen minimum zone (OMZ) of the Northwestern Indian Ocean may cause expansion/intensification of the regional OMZ.
显示更多 [+] 显示较少 [-]Baseline screening for the presence of antimicrobial resistance in E. coli isolated from Kuwait's marine environment
2018
Al-Sarawi, Hanan A. | Jha, Awadhesh N. | Baker-Austin, Craig | Al-Sarawi, Mohammad A. | Lyons, Brett P.
Here we present the findings of a study where 598 isolates of Escherichia coli (351 derived from seawater; 247 derived from the Venus clam, Circenita callipyga) were obtained from Kuwait's marine environment. Isolates were screened for their potential resistance to an array of 23 commonly deployed frontline antibiotics. Results demonstrate the resistant was widespread across all sites with high-levels of resistance (seawater: summer 89–64%; winter 90–57% and biota: summer 77%; winter 88%) observed to at least 1 of the 23 antibiotics tested. Resistance to Ampicillin was by far the most widely observed profile in seawater and biota across both summer and winter seasons, with 55.9 to 70.9% isolates displaying resistance to this antibiotic. This study demonstrates the potential of AMR screening to be used in Kuwait to detect issues related to water quality and the consequences it may pose for human health.
显示更多 [+] 显示较少 [-]210Po concentration in selected calanoid copepods in the northern Arabian Gulf
2018
Uddin, Saif | Behbehani, Montaha | Al-Ghadban, Abdulnabi | Sajid, Sufiya | Al-Zekri, W. | Ali, Mohammad | Al-Jutaili, Sarah | Al-Musallam, Lamya | Vinod, Vanitha | Al-Murad, Mohammad | Alam, Faiz
Copepods are the most abundant metazoans, forming a vital food chain link between the primary producers the phytoplankton and fish. This study presents baseline information on the concentration of ²¹⁰Po among calanoid copepods isolated from the Kuwait marine area. The concentration of ²¹⁰Po in six species of copepod, including Subeucalanus flemingeri, Parvocalanus crassirostis, Acartia pacifica, Calanopia elliptica, Acrocalanus gibber, and Euterpina acutifrons were 151.3–158.8 Bq kg⁻¹ wwt, 121.1–129.5 Bq kg⁻¹ wwt, 51.23–54.91 Bq kg⁻¹ wwt, 38.88–40.09 Bq kg⁻¹ wwt, 38.07–38.29 Bq kg⁻¹ wwt, and 33.46–36.50 Bq kg⁻¹ wwt, respectively.The ²¹⁰Po concentration in seawater shows a seasonal variation, with a higher concentration range of 0.58–0.70 mBq L⁻¹ during summer and autumn, while a lower concentration is found (0.30–0.38 mBq L⁻¹) during winter and spring. The concentration factor among the copepods varies between 8 ∗ 10⁴ and 5 ∗ 10⁵ that is an order of magnitude higher than the diatoms and dinoflagellates.
显示更多 [+] 显示较少 [-]Three-dimensional hydrodynamic modelling study of reverse estuarine circulation: Kuwait Bay
2018
Alosairi, Y. | Pokavanich, T. | Alsulaiman, N.
Hydrodynamics and associated environmental processes have always been of major concern to coastal-dependent countries, such as Kuwait. This is due to the environmental impact that accompanies the economic and commercial activities along the coastal areas. In the current study, a three-dimensional numerical model is utilized to unveil the main dynamic and physical properties of Kuwait Bay during the critical season. The model performance over the summer months (June, July and August 2012) is assessed against comprehensive field measurements of water levels, velocity, temperature and salinity data before using the model to describe the circulation as driven by tides, gravitational convection and winds. The results showed that the baroclinic conditions in the Bay are mainly determined by the horizontal salinity gradient and to much less extent temperature gradient. The gradients stretched over the southern coast of the Bay where dense water is found at the inner and enclosed areas, while relatively lighter waters are found near the mouth of the Bay. This gradient imposed a reversed estuarine circulation at the main axis of the Bay, particularly during neap tides when landward flow near the surface and seaward flow near the bed are most evident. The results also revealed that the shallow areas, including Sulaibikhat and Jahra Bays, are well mixed and generally flow in the counter-clockwise direction. Clockwise circulations dominated the northern portion of the Bay, forming a sort of large eddy, while turbulent fields associated with tidal currents were localized near the headlands.
显示更多 [+] 显示较少 [-]The environmental Kuznets curve relationship: a case study of the Gulf Cooperation Council region
2018
Alsamara, Mouyad | Mrabet, Zouhair | Ali Salman Saleh, | Anwar, Sajid
By using panel data over the 1980–2017 period and two alternative indicators of environmental pollution (carbon dioxide (CO₂) and sulfur dioxide (SO₂) emissions), this paper investigates the validity of the environmental Kuznets curve (EKC) hypothesis in the Gulf Cooperation Council (GCC) region. Using three alternative econometric estimation techniques, we find strong evidence of a long-run inverted U-shaped relationship between real GDP per capita and both environmental indicators in the GCC region. Country-level short-run analysis indicates that the EKC hypothesis holds for Bahrain, Kuwait, Qatar, Saudi Arabia, and the United Arab Emirates (UAE) when CO₂ emissions are used as a measure of environmental pollution. However, when SO₂ emissions are used as a measure of environmental pollution, the EKC hypothesis holds for Oman, Qatar, Saudi Arabia, and the UAE. The results of a recently developed panel causality test reveal one-way causality from real GDP per capita to CO₂ emissions and from real GDP per capita to SO₂ emissions.
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