خيارات البحث
النتائج 621 - 630 من 1,310
Distribution of butyltins in the waters and sediments along the coast of India النص الكامل
2011
Garg, Anita | Meena, Ram M. | Jadhav, Sangeeta | Bhosle, Narayan B.
Water and surface sediment samples were analyzed for butyltins (TBT, DBT, MBT) from various ports along the east and west coast of India. The total butyltin (TB) in water samples varied between ∼1.7 and 342ngSnl⁻¹, whereas for sediments it varied between below detection limit to 14861ngSng⁻¹ dry weight of sediment. On an average Chennai port recorded the highest level of butyltins in the sediments while Paradip recorded the highest level of butylins in the waters. A fairly good relationship between the TB in the sediment and overlying water samples, as well as between organic carbon and TB, implicates the importance of adsorption/desorption process in controlling the levels of TBT in these port areas. In India the data on organotin pollution is very sparse; most of the port areas have been surveyed for butyltins for the first time during this study.
اظهر المزيد [+] اقل [-]DDT in endangered Galapagos sea lions (Zalophus wollebaeki) النص الكامل
2011
Alava, Juan José | Ross, Peter S. | Ikonomou, Michael G. | Cruz, Marilyn | Jimenez-Uzcátegui, Gustavo | Dubetz, Cory | Salazar, Sandie | Costa, Daniel P. | Villegas-Amtmann, Stella | Howorth, Peter | Gobas, Frank A.P.C.
We characterize for the first time the presence of DDT and its metabolites in tropical Galapagos sea lions (Zalophus wolleabeki). ∑DDT concentrations in Galapagos sea lion pups sampled in 2005 and 2008 ranged from 16 to 3070μg/kg lipid. Concentrations of ∑DDT in pups in 2008 averaged 525μg/kg lipid and were 1.9 times higher than that (281μg/kg lipid) detected in pups in 2005. These concentrations are lower than those reported in many pinnipeds elsewhere, comparable to those in Hawaiian monk seals, and higher than those in southern elephant seals. The health risk characterization showed that 1% of the male pups exceeded the p,p′-DDE toxic effect concentration associated with anti-androgenic effects reported in rats. The findings provide preliminary guidance on the relationship between DDT use and ecological impacts, serving as a reference point against which possible future impact of tropical DDT use can be assessed.
اظهر المزيد [+] اقل [-]SWASV speciation of Cd, Pb and Cu for the determination of seawater contamination in the area of the Nicole shipwreck (Ancona coast, Central Adriatic Sea) النص الكامل
2011
Annibaldi, Anna | Illuminati, Silvia | Truzzi, Cristina | Scarponi, Giuseppe
The study reports for the first time on the heavy metal contamination of the waters surrounding a shipwreck lying on the sea floor. Square wave anodic stripping voltammetry has been used for a survey of the total and dissolved Cd, Pb and Cu contents of the seawater at the site of the sinking of the Nicole M/V (Coastal Adriatic Sea, Italy). Results show that the hulk has a considerable impact as regards all three metals in the bottom water, especially for the particulate fraction concentrations, which increased by factors of ∼9 (Cd), ∼3 (Pb) and ∼5 (Cu). The contaminated plume extended downstream for about 2miles. Much lower contamination was observed for dissolved bottom concentrations; nevertheless Pb (0.56±0.03nmol/L) is higher than the Italian legal limits established for 2015 and Cd (0.23±0.03nmol/L) is very close the limit of Cd will be exceeded if the hulk is not removed.
اظهر المزيد [+] اقل [-]PBDEs in the blubber of marine mammals from coastal areas of São Paulo, Brazil, southwestern Atlantic النص الكامل
2011
Yogui, G.T. | Santos, M.C.O. | Bertozzi, C.P. | Sericano, J.L. | Montone, R.C.
Limited information is available in the literature on the levels of brominated flame retardants in the southern hemisphere. This study presents concentrations of polybrominated diphenyl ethers (PBDEs) in the blubber of small cetaceans from the coast of São Paulo (Brazil), southwestern Atlantic. PBDE levels were highest in Stenellafrontalis (770ngg⁻¹ lipid) followed by Stenobredanensis (475ngg⁻¹ lipid), Sotaliaguianensis (65.6ngg⁻¹ lipid), Tursiopstruncatus (64.2ngg⁻¹ lipid) and Pontoporiablainvillei (60.3ngg⁻¹ lipid). In general, continental shelf individuals exhibited higher contamination than inshore animals. This might be related to larger prey items consumed by continental shelf dolphins. The pattern of contamination indicates that Penta-BDE commercial mixtures are a major source of PBDEs to top predators in the southwestern Atlantic. Congeners found in Octa-BDE formulations were not detected in the investigated animals.
اظهر المزيد [+] اقل [-]Occurrence of the toxic dinoflagellate Ostreopsis cf. ovata in relation with environmental factors in Monaco (NW Mediterranean) النص الكامل
2011
Cohu, Stéphanie | Thibaut, Thierry | Mangialajo, Luisa | Labat, Jean-Philippe | Passafiume, Ornella | Blanfuné, Aurélie | Simon, Nathalie | Cottalorda, Jean-Michel | Lemée, Rodolphe
To study environment characteristics favoring the toxic benthic dinoflagellate Ostreopsis cf. ovata, a survey was conducted in Monaco (NW Mediterranean Sea), in summers 2007 and 2008. Epiphytic and planktonic blooms occurred almost simultaneously and a high variation of abundances at low spatial scales was observed. An early and very marked bloom occurred in 2007, compared to a later and less abundant development in 2008. These distinct patterns in bloom timing corresponded with very different hydroclimatic scenarios in 2007 (hot spring and relatively cold summer) and 2008 (standard year compared to the median year profile estimated with data from 1995 to 2008). No clear impacts of summer seawater temperature, rainfall or nutrient concentrations were evident. Strong wind may favor the dispersal of benthic and planktonic cells. Our study suggests that further investigations are needed to examine the potential role of Ostreopsis nutritional mode (i.e. autotrophy vs. mixotrophy).
اظهر المزيد [+] اقل [-]Occurrence and distribution of hydrocarbons in the surface microlayer and subsurface water from the urban coastal marine area off Marseilles, Northwestern Mediterranean Sea النص الكامل
2011
Guigue, Catherine | Tedetti, Marc | Giorgi, Sébastien | Goutx, Madeleine
Aliphatic (AHs) and polycyclic aromatic hydrocarbons (PAHs) were analyzed in dissolved and particulate material from surface microlayer (SML) and subsurface water (SSW) sampled at nearshore observation stations, sewage effluents and harbour sites from Marseilles coastal area (Northwestern Mediterranean) in 2009 and 2010. Dissolved and particulate AH concentrations ranged 0.05–0.41 and 0.04–4.3μgl⁻¹ in the SSW, peaking up to 38 and 1366μgl⁻¹ in the SML, respectively. Dissolved and particulate PAHs ranged 1.9–98 and 1.9–21ngl⁻¹ in the SSW, amounting up 217 and 1597ngl⁻¹ in the SML, respectively. In harbours, hydrocarbons were concentrated in the SML, with enrichment factors reaching 1138 for particulate AHs. Besides episodic dominance of biogenic and pyrogenic inputs, a moderate anthropisation from petrogenic sources dominated suggesting the impact of shipping traffic and surface runoffs on this urbanised area. Rainfalls increased hydrocarbon concentrations by a factor 1.9–11.5 in the dissolved phase.
اظهر المزيد [+] اقل [-]Ostreopsis cf. ovata bloom in the northern Adriatic Sea during summer 2009: Ecology, molecular characterization and toxin profile النص الكامل
2011
Accoroni, Stefano | Romagnoli, Tiziana | Colombo, Federica | Pennesi, Chiara | Di Camillo, Cristina Gioia | Marini, Mauro | Battocchi, Cecilia | Ciminiello, Patrizia | Dell’Aversano, Carmela | Dello Iacovo, Emma | Fattorusso, Ernesto | Tartaglione, Luciana | Penna, Antonella | Totti, Cecilia
Intense blooms of the benthic dinoflagellate Ostreopsis cf. ovata have occurred in the northern Adriatic Sea since 2006. These blooms are associated with noxious effects on human health and with the mortality of benthic organisms because of the production of palytoxin-like compounds. The O. cf. ovata bloom and its relationships with nutrient concentrations at two stations on the Conero Riviera (northern Adriatic Sea) were investigated in the summer of 2009. O. cf. ovata developed from August to November, with the highest abundances in September (1.3×10⁶cellsg⁻¹ fw corresponding to 63.8×10³cellscm⁻²). The presence of the single O. cf. ovata genotype was confirmed by a PCR assay. Bloom developed when the seawater temperature was decreasing. Nutrient concentrations did not seem to affect bloom dynamics. Toxin analysis performed by high resolution liquid chromatography–mass spectrometry revealed a high total toxin content (up to 75pgcell⁻¹), including putative palytoxin and all the ovatoxins known so far.
اظهر المزيد [+] اقل [-]Testes specific accumulation of tributyltin in turbot Scophthalmus maximus from the southern Baltic Sea النص الكامل
2011
Gosz, E. | Horbowy, J. | Ruczyńska, W.
Concentrations of tributyltin (TBT) and its breakdown products, dibutyltin (DBT) and monobutyltin (MTB), were measured in tissues of male turbot Scophthalmus maximus from the Gulf of Gdańsk (GDA) and the Pomeranian Bay (POM) in the southern Baltic Sea. The fish (n=206) were collected during the spawning seasons of 2008–2009. All specimens were at the same maturity stage and in full breeding condition. The ripe testes of the turbot appeared to be a target tissue for TBT accumulation. We report that TBT is extensively eliminated at the specific whole-body level and that the males from TBT-contaminated location (GDA) reach this specific level at 23–24cm in total length.
اظهر المزيد [+] اقل [-]Pore water transport of enterococci out of beach sediments النص الكامل
2011
Phillips, Matthew C. | Solo-Gabriele, Helena M. | Reniers, A.J.H.M. | Wang, John D. | Kiger, Russell T. | Abdel-Mottaleb, Noha
Enterococci are used to evaluate the safety of beach waters and studies have identified beach sands as a source of these bacteria. In order to study and quantify the release of microbes from beach sediments, flow column systems were built to evaluate flow of pore water out of beach sediments. Results show a peak in enterococci (average of 10% of the total microbes in core) released from the sand core within one pore water volume followed by a marked decline to below detection. These results indicate that few enterococci are easily removed and that factors other than simple pore water flow control the release of the majority of enterococci within beach sediments. A significantly larger quantity and release of enterococci were observed in cores collected after a significant rain event suggesting the influx of fresh water can alter the release pattern as compared to cores with no antecedent rainfall.
اظهر المزيد [+] اقل [-]Antibiotic resistance of bacteria isolated from shrimp hatcheries and cultural ponds on Donghai Island, China النص الكامل
2011
Zhang, Yu Bin | Li, Yuan | Sun, Xing Li
The resistance of bacteria to 12 different antibiotics was investigated in shrimp farms on Donghai Island, China. Antibiotic-resistant bacteria were found to be widespread in shrimp farms, indicating a high environmental risk. Further, significant differences were found in bacterial strains among farms (ANOVA, p<0.05), showing resistance to antibiotics such as ampicillin, trimethoprim, compound sinomi, tetracycline, chloramphenicol and cefazolin. No significant differences in antibiotic resistance were found among 6 hatcheries evaluated in this study (ANOVA, p>0.05), between exalted and traditional shrimp ponds (ANOVA, p>0.05), and between cultural ponds and corresponding control water source sites (T-test, p>0.05). In cultural ponds, no significant difference in bacterial resistance to antibiotics was found between water and sediment (T-test, p>0.05), and antibiotic resistance of bacteria from water showed a significant positive correlation with that from sediment (p<0.05). Therefore, our study indicates that bacterial multiple antibiotic resistance (MAR) is more widespread in shrimp hatcheries than ponds.
اظهر المزيد [+] اقل [-]