Уточнить поиск
Результаты 901-910 из 3,240
Geochemical partitioning of Cu and Ni in mangrove sediments: Relationships with their bioavailability Полный текст
2015
Chakraborty, Parthasarathi | Ramteke, Darwin | Chakraborty, Sucharita
Sequential extraction study was performed to determine the concentrations of non-residual metal-complexes in the mangrove sediments from the Divar Island, (west coast of India). Accumulation of metal in the mangrove roots (from the same location) was determined and used as an indicator of bioavailability of metal. An attempt was made to establish a mechanistic linkage between the non-residual metal complexes and their bioavailability in the mangrove system. The non-residual fractions of Cu and Ni were mainly associated with Fe/Mn oxyhydroxide and organic phases in the sediments. A part of these metal fractions were bioavailable in the system. These two phases were the major controlling factors for Ni speciation and their bioavailability in the studied sediments. However, Cu was found to interact more strongly with the organic phases than Ni in the mangrove sediments. Organic phases in the mangrove sediments acted as buffer to control the speciation and bioavailability of Cu in the system.
Показать больше [+] Меньше [-]Sand patties provide evidence for the presence of Deepwater Horizon oil on the beaches of the West Florida Shelf Полный текст
2015
McDaniel, L.D. | Basso, J. | Pulster, E. | Paul, J.H.
The ecological consequences of the Deepwater Horizon (DWH) oil spill are both long-term and pervasive. The distribution of toxicity and mutagenicity in the Gulf of Mexico suggests oil from the DWH spill could have contaminated the West Florida Shelf (WFS). We utilized polycyclic aromatic hydrocarbon (PAH) analysis to determine presence and potential origin of oil contaminants in beach sand patty samples. PAH profiles from WFS beaches were statistically significantly similar to DWH contaminated samples from the Northeast Gulf of Mexico (Gulf Shores, AL; Ft. Pickens, FL). Dioctyl sodium sulfosuccinate (DOSS), a major component of Corexit 9500 dispersant was also detected in the sediments. DOSS concentrations ranged from 1.6 to 5.5ngg−1 dry weight. Additionally, two samples from DWH oil contaminated beaches were acutely toxic and one WFS beach sediment sample was mutagenic. These observations provide support for the theory that DWH oil made its way onto beaches of the WFS.
Показать больше [+] Меньше [-]Human health risk assessment of pesticide residues in snappers (Lutjanus) fish from the Navachiste Lagoon complex, Mexico Полный текст
2015
Granados-Galván, Ingrid Alejandra | Rodríguez-Meza, Durga Guadalupe | Luna-González, Antonio | González-Ocampo, Héctor Abelardo
Organochlorine pesticides (OCPs) residues were determined in fillets of Lutjanus colorado, L. argentiventris, and L. novemfasciatus. Fillet samples were collected bimonthly from February 2012 to February 2013. OCPs average concentrations do not differ significantly according to size, weight, or season, nor do they relate with the physico-chemical parameters of the sea water. The highest concentration and most frequently encountered OCPs were endosulfan sulfate, δ-HCH, and heptachlor epoxide, which indicates their use in the recent past and confirms their persistence. Average concentrations of ∑HCHs, ∑chlordane, and ∑heptachlor in samples were above cancer MRLs according to data from monthly consumed portions. HCHs and heptachlor are listed in Appendix III of the Rotterdam Convention of chemicals placed on a prior informed consent procedure for import and export purposes; they are considered illegal in Mexico. The OCPs concentrations above cancer MRLs in Lutjanus spp. turn its frequent consumption into a human health risk.
Показать больше [+] Меньше [-]Strategic planning to reduce conflicts for offshore wind development in Taiwan: A social marketing perspective Полный текст
2015
Chen, Jyun-Long | Liu, Hsiang-Hsi | Chuang, Ching-Ta
This study aims to improve the current inefficiency and ineffectiveness of communications among stakeholders when planning and constructing offshore wind farms (OWFs). An analysis using a social marketing approach with segmentation techniques is used to identify the target market based on stakeholders’ perceptions. The empirical results identify three stakeholder segments: (1) impact-attend group; (2) comprehensive group; and (3) benefit-attend group. The results suggest that communication should be implemented to alter stakeholders’ attitudes toward the construction of OWFs. Furthermore, based on the results of segmentation, target markets are identified to plan the communication strategies for reducing the conflicts among stakeholders of OWF construction. The results also indicated that in the planning phase of construction for OWFs, effective stakeholder participation and policy communication can enhance the perception of benefits to reduce conflict with local communities and ocean users.
Показать больше [+] Меньше [-]Human-induced ecological changes in western part of Indian Sundarban megadelta: A threat to ecosystem stability Полный текст
2015
Rakshit, Dibyendu | Sarkar, Santosh Kumar | Bhattacharya, Bhaskar Deb | Jonathan, M.P. | Biswas, Jayanta Kumar | Mondal, Priyanka | Mitra, Soumita
The study first illustrates a comprehensive account of large-scale changes in water quality characteristics and plankton community structure due to occurrence of Annual Gangasagar Festival (AGF) at Sagar Island, western part of Indian Sundarban megadelta for 3-year duration (2012–2014; n=36). About 1 million pilgrims across India converge to take their holy bath at the confluence of Hooghly estuary and Bay of Bengal during January each year. This mass scale bathing results negative impact on water quality due to high turbidity (14.02±2.34 NTU) coupled with low chlorophyll a (1.02±0.21mgm−3) and dissolved oxygen (3.94±1.1mgl−1). A marked decrease in abundance (from 4140 to 2997cellsl−1) and diversity (H′=2.72–1.33) of phytoplankton and microzooplankton tintinnids (from 450 to 328 ind l−1; H′=4.31–2.21) was recorded. The festival acts as multiple stressors modifying natural functions of the delta. Sound and sustainable management strategies are to be adopted to maintain the protection-usage equilibrium.
Показать больше [+] Меньше [-]Distribution, sources, and fluxes of heavy metals in the Pearl River Delta, South China Полный текст
2015
Geng, Junjie | Wang, Yiping | Luo, Hanjin
Riverine samples were collected at various locations in the Pearl River Delta (PRD) to determine the concentrations of heavy metals (Cr, Ni, Cu, Mn, Zn, Cd, and Pb) in time and space and to estimate the fluxes of heavy metals to the coastal waters off South China. Most of the elements exhibit clear temporal and spatial trends. Principal component analysis shows that surface erosion is the major factor affecting metal concentrations in particulates in the PRD. Natural geology is an important source of these heavy metals. The annual fluxes of Cr, Ni, Cu, Mn, Zn, Cd, and Pb in upstream and downstream were 445, 256, 241, 3293, 1279, 12, and 317t/year and 1823, 1144, 1786, 15,634, 6183, 74, and 2017t/year, respectively. A comparison indicated that the annual fluxes of Mn accounted for 1.3% of the global river fluxes, whereas other elements contribute <1%.
Показать больше [+] Меньше [-]Biodegradation of HDPE by Aspergillus spp. from marine ecosystem of Gulf of Mannar, India Полный текст
2015
Sangeetha Devi, Rajendran | Rajesh Kannan, Velu | Nivas, Duraisamy | Kannan, Kanthaiah | Chandru, Sekar | Robert Antony, Arokiaswamy
High density polyethylene (HDPE) is the most commonly found non-degradable solid waste among the polyethylene. In this present study, HDPE degrading various fungal strains were isolated from the polyethylene waste dumped marine coastal area and screened under in vitro condition. Based on weight loss and FT-IR Spectrophotometric analysis, two fungal strains designated as VRKPT1 and VRKPT2 were found to be efficient in HDPE degradation. Through the sequence analysis of ITS region homology, the isolated fungi were identified as Aspergillus tubingensis VRKPT1 and Aspergillus flavus VRKPT2. The biofilm formation observed under epifluorescent microscope had shown the viability of fungal strains even after one month of incubation. The biodegradation of HDPE film nature was further investigated through SEM analysis. HDPE poses severe environmental threats and hence the ability of fungal isolates was proved to utilize virgin polyethylene as the carbon source without any pre-treatment and pro-oxidant additives.
Показать больше [+] Меньше [-]Assessment of trace elements, POPs, 210Po and stable isotopes (15N and 13C) in a rare filter-feeding shark: The megamouth Полный текст
2015
Moura, Jailson Fulgencio de | Merico, Agostino | Montone, Rosalinda Carmela | Silva, Josilene | Seixas, Tércia Guedes | Godoy, José Marcus de Oliveira | Saint’Pierre, Tatiana Dillenburg | Hauser-Davis, Rachel Ann | Di Beneditto, Ana Paula Madeira | Reis, Estéfane Cardinot | Tavares, Davi Castro | Lemos, Leila Soledade | Siciliano, Salvatore
With less than 60 records being reported worldwide, the megamouth (Megachasma pelagios) is today one of the least known shark species inhabiting our oceans. Therefore, information concerning the biology and ecology of this enigmatic organism is very scarce and limited to feeding behaviour and preferred habitat. The present work reports new data on the concentrations of trace elements, organic mercury, POPs and 210Po in hepatic and muscular tissues of a specimen found stranded in the southeastern coast of Brazil. Additionally, we provide new evidence based on stable isotope analysis (δ15N and δ13C) confirming the preference for the pelagic habitat and the zooplanktivorous feeding behaviour of the megamouth. These results are consistent with the low concentrations of organic pollutant compounds and other elements measured in our samples.
Показать больше [+] Меньше [-]Pyrolysis–gas chromatography–mass spectrometry with electron-ionization or resonance-enhanced-multi-photon-ionization for characterization of polycyclic aromatic hydrocarbons in the Baltic Sea Полный текст
2015
Otto, Stefan | Streibel, Thorsten | Erdmann, Sabrina | Klingbeil, Sophie | Schulz-Bull, Detlef | Zimmermann, Ralf
Polycyclic aromatic hydrocarbons (PAH), as a part of dissolved organic matter (DOM), are environmental pollutants of the marine compartment. This study investigates the origin of PAH, which is supposed to derive mainly from anthropogenic activities, and their alteration along the salinity gradient of the Baltic Sea. Pyrolysis in combination with gas chromatography and two mass selective detectors in one measurement cycle are utilized as a tool for an efficient trace analysis of such complex samples, by which it is possible to detect degradation products of high molecular structures. Along the north–south transect of the Baltic Sea a slightly rising trend for PAH is visible. Their concentration profiles correspond to the ship traffic as a known anthropogenic source, underlined by the value of special isomer ratios such as phenanthrene and anthracene (0.31–0.45) or pyrene and fluoranthene (0.44–0.53). The detection of naphthalene and the distribution of its alkylated representatives support this statement.
Показать больше [+] Меньше [-]Impact of silver nanoparticles on benthic prokaryotes in heavy metal-contaminated estuarine sediments in a tropical environment Полный текст
2015
Antizar-Ladislao, B. | Bhattacharya, B.D. | Ray Chaudhuri, S. | Sarkar, S.K.
Little knowledge is available about the potential impact of commercial silver nanoparticles (Ag-NPs) on estuarine microbial communities. The Hugli river estuary, India, is susceptible to heavy metals pollution through boat traffic, and there is the potential for Ag-NP exposure via effluent discharged from ongoing municipal and industrial activities located in close proximity. This study investigated the effects of commercial Ag-NPs on native microbial communities in estuarine sediments collected from five stations, using terminal restriction fragment length polymorphism (T-RFLP) technique. An increase in the number of bacteria in consortium in sediments was observed following exposure to Ag-NPs. In general microbial communities may be resistant in estuarine systems to the antimicrobial effects of commercial Ag-NPs, but key microorganisms, such as Pelobacter propionicus, disappeared following exposure to Ag-NPs. In conclusion, the T-RFLP analysis indicated that Ag-NPs have the potential to shape estuarine sediment bacterial community structure.
Показать больше [+] Меньше [-]