خيارات البحث
النتائج 1731 - 1740 من 5,149
Seasonal variations and environmental risk assessment of trace elements in the sediments of Uppanar River estuary, southern India النص الكامل
2018
Gopal, V. | Nithya, B. | Magesh, N.S. | Jayaprakash, M.
Twenty four surface sediments were gathered from the Uppanar river estuary, southern India to evaluate the trace element contamination risk in the sediments. The circulation of organic matter and calcium carbonate were controlled by algal blooms and shell fragments. Moreover, the concentrations of iron and manganese in the estuarine sediments were possibly contributed by riverine sources and geogenic processes. The geoaccumulation index, enrichment factor and contamination factor reveals that the sediments were contaminated by copper and chromium. The pollution load index recommends that the estuarine sediments have the risk of pollution. The sediment pollution index highlights that the majority of the sediments are low polluted sediments. The potential ecological risk index discloses that the Uppanar river estuary is under moderate risk. The statistical analysis reveals that the organic matter content is managed by fine fractions and the majority of the trace elements are associated with each other having similar origin.
اظهر المزيد [+] اقل [-]Environmental radiation and potential ecological risk levels in the intertidal zone of southern region of Tamil Nadu coast (HBRAs), India النص الكامل
2018
Punniyakotti., J. | Ponnusamy., V.
Natural radioactivity content and heavy metal concentration in the intertidal zone sand samples from the southern region of Tamil Nadu coast, India, have been analyzed using gamma ray spectrometer and ICP-OES, respectively. From gamma spectral analysis, the average radioactivity contents of ²³⁸U, ²³²Th, and ⁴⁰K in the intertidal zone sand samples are 12.13±4.21, 59.03±4.26, and 197.03±26.24Bq/kg, respectively. The average radioactivity content of ²³²Th alone is higher than the world average value. From the heavy metal analysis, the average Cd, Cr, Cu, Ni, Pb, and Zn concentrations are 3.1, 80.24, 82.84, 23.66, 91.67, and 137.07ppm, respectively. The average Cr and Ni concentrations are lower, whereas other four metal (Cd, Cu, Pb, and Zn) concentrations are higher than world surface rock average values. From pollution assessment parameter values, the pollution level is “uncontaminated to moderately contaminated” in the study area.
اظهر المزيد [+] اقل [-]Effects of glyphosate herbicide on the gastrointestinal microflora of Hawaiian green turtles (Chelonia mydas) Linnaeus النص الكامل
2018
Kittle, Ronald P. | McDermid, Karla J. | Muehlstein, Lisa | Balazs, George H.
In Hawaii, glyphosate-based herbicides frequently sprayed near shorelines may be affecting non-target marine species. Glyphosate inhibits aromatic amino acid biosynthesis (shikimate pathway), and is toxic to beneficial gut bacteria in cattle and chickens. Effects of glyphosate on gut bacteria in marine herbivorous turtles were assessed in vitro. When cultures of mixed bacterial communities from gastrointestinal tracts of freshly euthanized green turtles (Chelonia mydas), were exposed for 24h to six glyphosate concentrations (plus deionized water control), bacterial density was significantly lower at glyphosate concentrations≥2.2×10⁻⁴gL⁻¹ (absorbance measured at 600nm wavelength). Using a modified Kirby-Bauer disk diffusion assay, the growth of four bacterial isolates (Pantoea, Proteus, Shigella, and Staphylococcus) was significantly inhibited by glyphosate concentrations≥1.76×10⁻³gL⁻¹. Reduced growth or lower survival of gut bacteria in green turtles exposed to glyphosate could have adverse effects on turtle digestion and overall health.
اظهر المزيد [+] اقل [-]Effects of seawater mixing on the mobility of trace elements in acid phosphogypsum leachates النص الكامل
2018
Papaslioti, Evgenia-Maria | Pérez López, Rafael | Parviainen, Annika | Sarmiento, Aguasanta M. | Nieto, José M. | Marchesi, Claudio | Delgado-Huertas, Antonio | Garrido, Carlos J.
Effects of seawater mixing on the mobility of trace elements in acid phosphogypsum leachates النص الكامل
2018
Papaslioti, Evgenia-Maria | Pérez López, Rafael | Parviainen, Annika | Sarmiento, Aguasanta M. | Nieto, José M. | Marchesi, Claudio | Delgado-Huertas, Antonio | Garrido, Carlos J.
This research reports the effects of pH increase on contaminant mobility in phosphogypsum leachates by seawater mixing, as occurs with dumpings on marine environments. Acid leachates from a phosphogypsum stack located in the Estuary of Huelva (Spain) were mixed with seawater to achieve gradually pH7. Concentrations of Al, Fe, Cr, Pb and U in mixed solutions significantly decreased with increasing pH by sorption and/or precipitation processes. Nevertheless, this study provides insight into the high contribution of the phosphogypsum stack to the release of other toxic elements (Co, Ni, Cu, Zn, As, Cd and Sb) to the coastal areas, as 80–100% of their initial concentrations behaved conservatively in mixing solutions with no participation in sorption processes. Stable isotopes ruled out connexion between different phosphogypsum-related wastewaters and unveiled possible weathering inputs of estuarine waters to the stack. The urgency of adopting effective restoration measures in the study area is also stressed.
اظهر المزيد [+] اقل [-]Effects of seawater mixing on the mobility of trace elements in acid phosphogypsum leachates النص الكامل
2018
Papaslioti, Evgenia-Maria | Pérez-López, Rafael | Parviainen, Annika Jenni Johana | Sarmiento, Aguasanta M. | Nieto, José Miguel | Marchesi, Claudio | Delgado-Huertas, Antonio | Garrido, Carlos Jesús
This work was supported by the Regional Government of Andalusia through the research project FOREVER (P12-RNM-2260) and the Spanish Ministry of Economic and Competitiveness through the research project CAPOTE (CGL2017-86050-R). The authors are very grateful to the funding support for the Committee of Experts on “The environmental diagnosis and the proposal of measures of restoration of the phosphogypsum stacks of Huelva”, appointed by the City Hall of Huelva. Dr. A Parviainen acknowledges the ‘Juan de la Cierva – Formación’ (FJCI-2014-19582) Fellowship and Dr. C. Marchesi the “Ramón y Cajal” (RYC-2012-11314) Fellowship financed by the Spanish Ministry of Economy and Competitiveness. | This research reports the effects of pH increase on contaminant mobility in phosphogypsum leachates by seawater mixing, as occurs with dumpings on marine environments. Acid leachates from a phosphogypsum stack located in the Estuary of Huelva (Spain) were mixed with seawater to achieve gradually pH 7. Concentrations of Al, Fe, Cr, Pb and U in mixed solutions significantly decreased with increasing pH by sorption and/or precipitation processes. Nevertheless, this study provides insight into the high contribution of the phosphogypsum stack to the release of other toxic elements (Co, Ni, Cu, Zn, As, Cd and Sb) to the coastal areas, as 80–100% of their initial concentrations behaved conservatively in mixing solutions with no participation in sorption processes. Stable isotopes ruled out connexion between different phosphogypsum-related wastewaters and unveiled possible weathering inputs of estuarine waters to the stack. The urgency of adopting effective restoration measures in the study area is also stressed. | Regional Government of Andalusia FOREVER (P12-RNM-2260) | Spanish Ministry of Economy and Competitiveness CAPOTE (CGL2017-86050-R), (FJCI-2014-19582), (RYC-2012-11314) | Committee of Experts, City Hall of Huelva
اظهر المزيد [+] اقل [-]Spatial distribution and ecological risk assessment of heavy metals in coastal surface sediments in the Hebei Province offshore area, Bohai Sea, China النص الكامل
2018
Ding, Xigui | Ye, Siyuan | Yuan, Hongming | Krauss, Ken W.
Seven hundred and nine surface sediment samples, along with deeper sediment samples, were collected from Hebei Province along the coastal section of the Bohai Sea, China, and analyzed for grain size, concentrations of organic carbon (Corg) and heavy metals (Cu, Pb, Zn, Cr, Cd, As, and Hg). Results indicated that the average concentrations in the sediments were 16.1 mg/kg (Cu), 19.4 mg/kg (Pb), 50 mg/kg (Zn), 48.8 mg/kg (Cr), 0.1 mg/kg (Cd), 8.4 mg/kg (As), and 20.3 μg/kg (Hg). These concentrations generally met the China Marine Sediment Quality criteria. However, both pollution assessments indicated moderate to strong Cd and Hg contamination in the study area. The potential ecological risk index suggested that the combined ecological risk of the seven studied metals may be low, but that 24.5% of the sites, where sediments were finer and higher in Corg concentration, had high ecological risk in Hg and Cd pollution.
اظهر المزيد [+] اقل [-]Troubles in the paradise: Litter and its scenic impact on the North Santa Catarina island beaches, Brazil النص الكامل
2018
Corraini, Natália Ramos | de Souza de Lima, André | Bonetti, Jarbas | Rangel-Buitrago, Nelson
Eight touristic beaches along the north coast of Santa Catarina Island, Brazil were assessed to determine litter influence on scenic quality. The application of the Coastal Scenic Evaluation System (CSES) categorized these beaches into four of the five available classes. Six of the investigated beaches belong to Class III (n = 3) and V (n = 3), while two beaches correspond to Class II and Class IV. Class I beaches were not found. A total amount of 4291 litter items weighing 29 kg were collected with average abundances of 0.29 items m2. Beach user's habits as well bad management practices along the adjoining river basins play an essential role on litter source, and are directly responsible for the decline of scenic quality of Santa Catarina Island Beaches. In fact, litter has a direct relation with the low scenic scores determined in the surveyed beaches.
اظهر المزيد [+] اقل [-]Perspectives on using marine species as bioindicators of plastic pollution النص الكامل
2018
Bonanno, Giuseppe | Orlando Bonaca, Martina
The ever-increasing level of marine pollution due to plastic debris is a globally recognized threat that needs effective actions of control and mitigation. Using marine organisms as bioindicators of plastic pollution can provide crucial information that would better integrate the spatial and temporal presence of plastic debris in the sea. Given their long and frequent migrations, numerous marine species that ingest plastics can provide information on the presence of plastic debris but only on large spatial and temporal scales, thus making it difficult to identify quantitative correlations of ingested plastics within well-defined spatio-temporal patterns. Given the complex dynamics of plastics in the sea, the biomonitoring of marine plastic debris should rely on the combination of several bioindicator species with different characteristics that complement each other. Other critical aspects include the standardization of sampling protocols, analytical detection methods and metrics to evaluate the effects of ingested plastics in marine species.
اظهر المزيد [+] اقل [-]Carapace asymmetry: A possible biomarker for metal accumulation in adult olive Ridleys marine turtles? النص الكامل
2018
Cortés-Gómez, Adriana A. | Romero, Diego | Girondot, Marc
The Olive Ridley marine turtle (Lepidochelys olivacea) is characterized by individual morphological variability in the number and shape of scutes. The influence of pollutants on developmental instability and one of its consequences, the asymmetry of individuals, has been demonstrated in several species, especially invertebrates and some birds. However, the use of this asymmetry as a biomarker of contamination in adult individuals has never been explored. We developed an index to quantify developmental instability (DIx) based on the number and relative size of costal carapace scutes. The link between DIx and inorganic elements concentrations was explored in various tissues of stranded turtles from the Southern Mexican Pacific. The relationships between adult contamination and DIx could directly or indirectly reflect (i) the disruption of metal elimination in the adult stage dependent on embryonic perturbation and thus determining DIx, (ii) the difference in metal absorption dependent on DIx status, or (iii) DIx linked to other unknown factors.
اظهر المزيد [+] اقل [-]Technologies for the marking of fishing gear to identify gear components entangled on marine animals and to reduce abandoned, lost or otherwise discarded fishing gear النص الكامل
2018
He, Pingguo | Suuronen, Petri
Technologies for the marking of fishing gear to identify gear components entangled on marine animals and to reduce abandoned, lost or otherwise discarded fishing gear النص الكامل
2018
He, Pingguo | Suuronen, Petri
Fishing gears are marked to establish and inform origin, ownership and position. More recently, fishing gears are marked to aid in capacity control, reduce marine litter due to abandoned, lost or otherwise discarded fishing gear (ALDFG) and assist in its recovery, and to combat illegal, unreported and unregulated (IUU) fishing. Traditionally, physical marking, inscription, writing, color, shape, and tags have been used for ownership and capacity purposes. Buoys, lights, flags, and radar reflectors are used for marking of position. More recently, electronic devices have been installed on marker buoys to enable easier relocation of the gear by owner vessels. This paper reviews gear marking technologies with focus on coded wire tags, radio frequency identification tags, Automatic Identification Systems, advanced electronic buoys for pelagic longlines and fish aggregating devices, and re-location technology if the gear becomes lost.
اظهر المزيد [+] اقل [-]Technologies for the marking of fishing gear to identify gear components entangled on marine animals and to reduce abandoned, lost or otherwise discarded fishing gear النص الكامل
2018
He, Pingguo | Suuronen, Petri | University of Massachusetts Dartmouth | Food and Agriculture Organisation of the United Nations | Luke / Luonnonvarat / Akvaattisten populaatioiden dynamiikka (4100110910) | 4100110910
Comparative risk assessment of spill response options for a deepwater oil well blowout: Part III. Stakeholder engagement النص الكامل
2018
Walker, Ann Hayward | Scholz, Debra | McPeek, Melinda | French-McCay, Deborah | Rowe, Jill | Bock, Michael | Robinson, Hilary | Wenning, Richard
This paper describes oil spill stakeholder engagement in a recent comparative risk assessment (CRA) project that examined the tradeoffs associated with a hypothetical offshore well blowout in the Gulf of Mexico, with a specific focus on subsea dispersant injection (SSDI) at the wellhead. SSDI is a new technology deployed during the Deepwater Horizon (DWH) oil spill response. Oil spill stakeholders include decision makers, who will consider whether to integrate SSDI into future tradeoff decisions. This CRA considered the tradeoffs associated with three sets of response strategies: (1) no intervention; (2) mechanical recovery, in-situ burning, and surface dispersants; and, (3) SSDI in addition to responses in (2). For context, the paper begins with a historical review of U.S. policy and engagement with oil spill stakeholders regarding dispersants. Stakeholder activities throughout the project involved decision-maker representatives and their advisors to inform the approach and consider CRA utility in future oil spill preparedness.
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