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Результаты 741-750 из 2,459
Increased zooplankton PAH concentrations across hydrographic fronts in the East China Sea
2014
Hung, Chin-Chang | Ko, Fung-Chi | Gong, Gwo-Ching | Chen, Kuo-Shu | Wu, Jian-Ming | Chiang, Hsin-Lun | Peng, Sen-Chueh | Santschi, Peter H.
The Changjiang has transported large quantities of polycyclic aromatic hydrocarbons (PAHs) to the East China Sea (ECS), but information of these pollutants in zooplankton is limited. To understand PAHs pollution in zooplankton in the ECS, total concentrations of PAHs in zooplankton from surface waters were measured. Values of PAHs ranged from 2 to 3500ngm−3 in the ECS, with highest PAHs levels located at the salinity front between the Changjiang Diluted Water (CDW) and the mid-shelf waters. In contrast, concentrations of zooplankton PAHs in the mid-shelf and outer-shelf waters were significantly lower (2–23ngm−3) than those in the CDW. These results demonstrate that PAHs are conspicuously accumulated in zooplankton at the salinity front between the CDW and the mid-shelf waters. These higher levels of PAHs in zooplankton at the salinity front may be further biomagnified in marine organisms of higher trophic levels through their feeding activities.
Показать больше [+] Меньше [-]Enrichment and partitioning of polycyclic aromatic hydrocarbons in the sea surface microlayer and subsurface water along the coast of Xiamen Island, China
2014
Ya, Miao-Lei | Wang, Xin-Hong | Wu, Yu-Ling | Ye, Cui-Xing | Li, Yong-Yu
Sea microlayer (SML) and subsurface water (SSW) samples were collected around Xiamen Island to study the enrichment and partitioning of polycyclic aromatic hydrocarbons (PAHs). Total PAH concentrations ranged from 93.43 to 411.05ng L−1 in the SML and 49.29–279.42ng L−1 in the SSW. Compared with the results of previous studies before pollution control measurements, PAHs levels decreased significantly. The enrichment factors (EFs) of dissolved and particulate PAHs varied from 0.68 to 2.71 and 0.43–3.56. EFs showed the consistent enrichment trends with sites and exhibited different enrichment characteristics between 2 and 3 ring PAHs and 4 ring PAHs. Furthermore, the much higher concentrations of BaP (strong carcinogenicity) were accompanied by higher EFs in the SML samples from the Western Xiamen Harbour, which together indicated the risk of impacts to the fish eggs that usually float on the SML water after exposure to oil spills and combustion, contributed directly by the port and shipping activities.
Показать больше [+] Меньше [-]The traffic linked urban ambient air superfine and ultrafine PM1 mass concentration, contents of pro–oxidant chemicals, and their seasonal drifts in Lucknow, India
2014
Verma, Mukesh Kumar | Singh Chauhan, Lalit Kumar | Sultana, Sarwat | Kumar, Sushil
The anthropogenic PM2.5 in ambient air is implicated in the increased health risks and morbidities of urban subjects. However in the literature, there is a limited information on mass concentrations and size segregated chemical profile of ultrafine and superfine PM1 fractions of traffic linked urban ambient air. The size, and the adsorbed chemicals, and response to seasonal change in this submicron range of particles have seldom been studied so far. We have looked into these aspects in urban ambient air of Lucknow Uttar Pradesh India. A 10–stage MOUDI cascade impactor sampled the superfine (PM0.56, PM0.32, PM0.18) and ultrafine particles (PM0.1, PM0.056) distributed in traffic linked ambient air. We studied their morphology, mass concentrations, the adsorbed metal contents and organic chemical moieties using TEM, gravimetric analyses, AAS, and FTIR spectroscopy. A change in their contents and profile with season was also examined. Results revealed spherical and fractal shapes of PM0.1, 50nm–2μm size range of PM0.56 fractions, and 10–100nm size range of constituent spherules. Gravimetric analyses disclosed mass concentrations and multifold increases in their levels in winter. Cr, Cd, Ni, Pb and transition element Cu, Fe were found to be present in the studied particles. The presence of aliphatic and aromatic hydrocarbons with hydroxyl, carbonyl, and ketone groups were also found and displayed changes in their levels with season. Presence of organonitrate compounds indicated the role of submicron and nanosize particulates in secondary aerosol formation also. Results are important for epidemiological studies and public policy on superfine and ultrafine particulate matter in urban ambient air for identification of toxicity risk or health hazard, air quality monitoring and regulation.
Показать больше [+] Меньше [-]Impacts of Macondo oil from Deepwater Horizon spill on the growth response of the common reed Phragmites australis: A mesocosm study
2014
Judy, Chad R. | Graham, Sean A. | Lin, Qianxin | Hou, Aixin | Mendelssohn, I. A.
We investigated impacts of Macondo MC252 oil from the Deepwater Horizon (DWH) spill on the common reed Phragmites australis (Cav.) Trin. ex Steud., a dominant species of the Mississippi River Delta. In greenhouse experiments, we simulated the most common DWH oiling scenarios by applying weathered and emulsified Macondo oil to aboveground shoots at varying degrees of coverage (0–100%) or directly to marsh soil at different dosages (0–16Lm−2). P. australis exhibited strong resistance to negative impacts when oil was applied to shoots alone, while reductions in above- and belowground plant growth were apparent when oil was applied to the soil or with repeated shoot-oiling. Although soil-oiling compromised plant function, mortality of P. australis did not occur. Our results demonstrate that P. australis has a high tolerance to weathered and emulsified Macondo oil, and that mode of exposure (aboveground versus belowground) was a primary determinant of impact severity.
Показать больше [+] Меньше [-]Evaluation of the levels of alcohol sulfates and ethoxysulfates in marine sediments near wastewater discharge points along the coast of Tenerife Island
2014
Fernández-Ramos, C. | Ballesteros, O. | Zafra-Gómez, A. | Camino-Sánchez, F.J. | Blanc, R. | Navalón, A. | Pérez-Trujillo, J.P. | Vílchez, J.L.
Alcohol sulfates (AS) and alcohol ethoxysulfates (AES) are all High Production Volume and ‘down-the-drain’ chemicals used globally in detergent and personal care products, resulting in low levels ultimately released to the environment via wastewater treatment plant effluents. They have a strong affinity for sorption to sediments. Almost 50% of Tenerife Island surface area is environmentally protected. Therefore, determination of concentration levels of AS/AES in marine sediments near wastewater discharge points along the coast of the Island is of interest. These data were obtained after pressurized liquid extraction and liquid chromatography–tandem mass spectrometry analysis. Short chains of AES and especially of AS dominated the homologue distribution for AES. The Principal Components Analysis was used. The results showed that the sources of AS and AES were the same and that both compounds exhibit similar behavior. Three different patterns in the distribution for homologues and ethoxymers were found.
Показать больше [+] Меньше [-]Biomarkers of endocrine disruption in juveniles and females of the estuarine fish Pomatoschistus microps
2014
Dias, Lídia C.A. | Soares, Amadeu M.V.M. | Ferreira, Abel L.G. | Santos, Cátia S. | Monteiro, Marta S.
The presence of endocrine disruptor chemicals (EDCs) in aquatic compartments, including estuaries, has been object of major concern. However, the effects of EDCs on autochthonous estuarine fish species are far less known than in freshwater fish. Therefore, the response of biomarkers in the estuarine fish Pomatoschistus microps was evaluated after 21-days of exposure to different EDCs: 17β-estradiol (E2); PCB-77 and p,p′DDE. In juveniles, Vtg (vitellogenin)-like proteins were significantly induced by E2. PCB-77 led to a decrease of Vtg-like proteins in juveniles, while in female liver they increased at the highest concentrations tested, suggesting a mode of action of PCB-77 that depends on the fish life stage. p,p′-DDE did not induce significant changes in Vtg-like proteins. Overall, P. microps juveniles seemed to respond to environmental relevant concentrations of EDCs. Thus, the evaluation of Vtg-like proteins in this life stage seems to be a promising tool to track EDC contamination in biomonitoring studies.
Показать больше [+] Меньше [-]Role of gamma radiation in changing phytotoxic effect of elevated level of ozone in Trifolium alexandrinum L. (Clover)
2014
Chaudhary, Nivedita | Agrawal, Shashi Bhushan
The present study was conducted on clover (Trifolium alexandrinum L. cv Wardan), to investigate the effect of ambient and elevated (ambient +10 ppb O3) ozone (O3) on plants grown in open top chambers (OTCs) germinated from gamma (γ) irradiated seeds. Dry seeds were subjected to irradiation with 0, 5, 10 and 20 krad doses of γ rays from 60Co source. Dose dependent differential responses were observed on growth and biomass, photosynthetic pigments, metabolites, antioxidative defense system of plant. Growth parameters and biomass of plants were severely affected under elevated O3 with increasing radiation doses, except, 5 krad which showed a reverse trend of response. Photosynthetic pigments and total soluble proteins were also reduced with higher dose of γ radiation and elevated O3. Reactive oxygen species formation and membrane damage increased significantly to different extents. Plants grown from seeds irradiated with low dose (5 krad) of γ irradiation depicted more induction of antioxidants (enzymatic and non–enzymatic) than higher doses suggesting their high ameliorative capability against elevated O3. Principal component analysis has also confirmed that plants grown from 5 krad γ irradiated seeds performed better against O3 depicting reduction in negative effect against elevated O3. The experimental findings evidently showed that 5 krad γ radiations altered the O3 induced stress and thus minimized the loss in biomass of the test plant.
Показать больше [+] Меньше [-]Sediment PAH: Contrasting levels in the Caspian Sea and Anzali Wetland
2014
Yancheshmeh, Rokhsareh Azimi | Bakhtiari, Alireza Riyahi | Mortazavi, Samar | Savabieasfahani, Mozhgan
A comparative study of 23 PAH congeners in sediment of the Caspian Sea coast and Anzali Wetland was conducted in 2010. Surface sediment was analyzed using chromatography and mass spectrometry. Total PAH concentrations ranged between 212 and 9009ngg−1dw. Spatial distribution maps revealed that PAH levels were higher in the coastal areas of the Caspian Sea where oil related activities have been common since 1800’s. Diagnostic ratios analysis indicated that PAHs largely originated from petrogenic processes. PAH toxicity level was assessed using sediment quality guidelines and toxic equivalent concentrations to determine toxic effects on marine organism. Based on these investigations, in our study areas, the probability of toxicity for benthic organisms is “low to medium”. The toxic equivalent concentrations of carcinogenic PAHs varied between 11 and 231ng TEQ/g; higher total toxic equivalent concentrations values were found in the coastal areas of the Caspian Sea.
Показать больше [+] Меньше [-]The use of cholinesterase as potential biomarker: In vitro characterization in the polychaete Capitella teleta
2014
Gomes, Isa D.L. | Lemos, Marco F.L. | Soares, Amadeu M.V.M. | Barata, Carlos | Faria, Melissa
The ecological relevance of polychaetes coupled with their easy culture and maintenance in the laboratory, has led them to become increasingly used in marine ecotoxicological studies, raising the need to validate frequently applied monitoring tools at various biological levels. The present study was aimed to characterize the cholinesterases (ChE) activity in the polychaete Capitella teleta, using three substrates (acetylthiocholine iodide, propionylthiocholine iodide, and S-butyrylthiocholine iodide) and four known inhibitors (eserine hemisulfate, BW284c51, iso-OMPA and chlorpyrifos-oxon). Results showed that most of the measured cholinesterase activity was acetylcholinesterase (AChE). Inhibition of enzyme kinetic experiments denoted that sensitivity of C. teleta’s ChE to the organophosphorous metabolite chlorpyrifos-oxon (IC50=60.72nM) was analogous to some fish species. This study highlights the relevance of ChE characterization before its use as a biomarker in ecotoxicology and biomonitoring studies.
Показать больше [+] Меньше [-]High-levels of microplastic pollution in a large, remote, mountain lake
2014
Free, Christopher M. | Jensen, Olaf P. | Mason, Sherri A. | Eriksen, Marcus | Williamson, Nicholas J. | Boldgiv, Bazartseren
Despite the large and growing literature on microplastics in the ocean, little information exists on microplastics in freshwater systems. This study is the first to evaluate the abundance, distribution, and composition of pelagic microplastic pollution in a large, remote, mountain lake. We quantified pelagic microplastics and shoreline anthropogenic debris in Lake Hovsgol, Mongolia. With an average microplastic density of 20,264 particles km−2, Lake Hovsgol is more heavily polluted with microplastics than the more developed Lakes Huron and Superior in the Laurentian Great Lakes. Fragments and films were the most abundant microplastic types; no plastic microbeads and few pellets were observed. Household plastics dominated the shoreline debris and were comprised largely of plastic bottles, fishing gear, and bags. Microplastic density decreased with distance from the southwestern shore, the most populated and accessible section of the park, and was distributed by the prevailing winds. These results demonstrate that without proper waste management, low-density populations can heavily pollute freshwater systems with consumer plastics.
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