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Polycyclic aromatic hydrocarbons, polychlorinated biphenyls and organochlorine pesticides in European hake (Merluccius merluccius) muscle from the Western Mediterranean Sea Texte intégral
2015
Moraleda-Cibrián, Núria | Carrassón, Maite | Rosell-Melé, A. (Antoni)
Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) were quantified in muscle tissue of European hake, an ecologically and commercially important species. Samples were collected from the Western Mediterranean, in seven different stations at different depths and a batch was bought in a local market. PCBs are the dominant pollutants, but the overall concentrations do not show significant differences between the different specimens analyzed from various locations, with the exception of the concentration of PCBs at a shallow station close to the River Besòs mouth. This probably suggests that generally the pollutants in hake from the Western Mediterranean derive from historical and non-point sources. The occurrence of pollutants is widespread in the samples but their concentration is below recommended legal limits for fish or other foodstuffs.
Afficher plus [+] Moins [-]Debris ingestion by juvenile marine turtles: An underestimated problem Texte intégral
2015
Santos, Robson Guimarães | Andrades, Ryan | Boldrini, Marcillo Altoé | Martins, Agnaldo Silva
Marine turtles are an iconic group of endangered animals threatened by debris ingestion. However, key aspects related to debris ingestion are still poorly known, including its effects on mortality and the original use of the ingested debris. Therefore, we analysed the impact of debris ingestion in 265 green turtles (Chelonia mydas) over a large geographical area and different habitats along the Brazilian coast. We determined the death rate due to debris ingestion and quantified the amount of debris that is sufficient to cause the death of juvenile green turtles. Additionally, we investigated the original use of the ingested debris. We found that a surprisingly small amount of debris was sufficient to block the digestive tract and cause death. We suggested that debris ingestion has a high death potential that may be masked by other causes of death. An expressive part of the ingested debris come from disposable and short-lived products.
Afficher plus [+] Moins [-]Natural dispersion revisited Texte intégral
2015
Johansen, Øistein | Reed, Mark | Bodsberg, Nils Rune
This paper presents a new semi-empirical model for oil droplet size distributions generated by single breaking wave events. Empirical data was obtained from laboratory experiments with different crude oils at different stages of weathering. The paper starts with a review of the most commonly used model for natural dispersion, which is followed by a presentation of the laboratory study on oil droplet size distributions formed by breaking waves conducted by SINTEF on behalf of the NOAA/UNH Coastal Response Research Center. The next section presents the theoretical and empirical foundation for the new model. The model is based on dimensional analysis and contains two non-dimensional groups; the Weber and Reynolds number. The model was validated with data from a full scale experimental oil spill conducted in the Haltenbanken area offshore Norway in July 1982, as described in the last section of the paper.
Afficher plus [+] Moins [-]Enterococcus species diversity and molecular characterization of biomarker genes in Enterococcus faecalis in Port Blair Bay, Andaman and Nicobar Islands, India Texte intégral
2015
Meena, Balakrishnan | Anburajan, Lawrance | Sathish, Thadikamala | Raghavan, Rangamaran Vijaya | Jha, Dilip Kumar | Venkateshwaran, Pitchiah | Das, Apurba Kumar | Dheenan, Palaiya Sukumaran | Vinithkumar, Nambali Valsalan | Dharani, Gopal | Kirubagaran, Ramalingam
This study was performed to evaluate the abundance and diversity of Enterococcus sp. and the distribution of biomarker genes in Enterococcus faecalis in Port Blair Bay, Andaman and Nicobar Islands. The Enterococcus sp. densities at the seven sampling stations were highly influenced by tidal fluctuations and season. The distributions and diversities of species varied in the inner and outer regions of Port Blair Bay. Among the 1816 total isolates, the occurrence of fecal Enterococcus was high (1.78×104CFU/100mL) in Phoenix Bay. Moreover, 67.76% of the isolates were identified as Enterococcus, and the most frequently identified species were E. hirae, E. avium and E. faecalis. Assessments of antibiotic resistance and biomarker genes revealed the maximum occurrence in the Aberdeen Bay isolates. The most prevalent biomarker genes observed in the E. faecalis isolates were gelE and asa1, whereas cyl was not found among the isolates. In silico sequence analysis of biomarker genes of E. faecalis also revealed that they are evolutionarily well conserved with those of earlier reports. Further, multivariate analysis distinguished the JB, PB and OS stations from the other stations according to distinctive microbial densities and compositions. In addition, the Shannon-Wiener diversity indices and box-whisker plots further facilitated and supported the multivariate results.
Afficher plus [+] Moins [-]Assessing the water quality response to an alternative sewage disposal strategy at bathing sites on the east coast of Ireland Texte intégral
2015
Bedri, Zeinab | O’Sullivan, John J. | Deering, Louise A. | Demeter, Katalin | Masterson, Bartholomew | Meijer, Wim G. | O’Hare, Gregory
A three-dimensional model is used to assess the bathing water quality of Bray and Killiney bathing sites in Ireland following changes to the sewage management system. The model, firstly calibrated to hydrodynamic and water quality data from the period prior to the upgrade of the Wastewater Treatment Works (WwTW), was then used to simulate Escherichia coli (E. coli) distributions for discharge scenarios of the periods prior to and following the upgrade of the WwTW under dry and wet weather conditions. E. coli distributions under dry weather conditions demonstrate that the upgrade in the WwTW has remarkably improved the bathing water quality to a Blue Flag status.The new discharge strategy is expected to drastically reduce the rainfall-related incidents in which environmental limits of the Bathing Water Directive are breached. However, exceedances to these limits may still occur under wet weather conditions at Bray bathing site due to storm overflows that may still be discharged through two sea outfalls offshore of Bray bathing site.
Afficher plus [+] Moins [-]Strategy for assessing impacts in ephemeral tropical seagrasses Texte intégral
2015
Hovey, Renae K. | Statton, John | Fraser, Matthew W. | Ruiz-Montoya, Leonardo | Zavala-Perez, Andrea | Rees, Max | Stoddart, James | Kendrick, Gary A.
We investigated the phenology and spatial patterns in Halophila decipiens by assessing biomass, reproduction and seed density in ~400 grab samples collected across nine sites (8 to 14m water depth) between June 2011 and December 2012. Phenology correlated with light climate which is governed by the summer monsoon (wet period). During the wet period, sedimentary seed banks prevailed, varying spatially at both broad and fine scales, presenting a source of propagules for re-colonisation following the unfavourable growing conditions of the monsoon. Spatial patterns in H. decipiens biomass following monsoon conditions were highly variable within a landscape that largely comprised potential seagrass habitat. Management strategies for H. decipiens and similar transient species must recognise the high temporal and spatial variability of these populations and be underpinned by a framework that emphasises vulnerability assessments of different life stages instead of relying solely on thresholds for standing stock at fixed reference sites.
Afficher plus [+] Moins [-]Distribution of trace metals and the benthic foraminiferal assemblage as a characterization of the environment in the north Minjiang River Estuary (Fujian, China) Texte intégral
2015
Li, Tao | Li, Xuejie | Zhong, Hexian | Yang, Chupeng | Sun, Guihua | Luo, Weidong
A study of the total benthic foraminifera was carried out in 173 surficial sediment samples collected from the north Minjiang River Estuary and two bays. Foraminiferal assemblages are dominated by Ammonia tepida and subordinately by Elphidium advenum. Trace metal analyses reveal that the study area is unpolluted to moderately polluted with As, Cr, Cu, Ni, Pb, and Zn. The metal distribution has an affinity with fine-grained sediment. Five metal groups are recognized based on their distribution patterns: (1) As, Cr, Cu, Ga, Ni, V, and Zn, (2) Hg, Pb, and Sb, (3) Ba and Zr, (4) Rb and Y, and (5) Sr. The species-environment relationship showed that the species composition is adversely influenced by Cr, Cu, Ga, Pb, Rb, Zn, and Zr, whereas sand may exert a positive influence on Quinqueloculina. This study supports the adaptability of using benthic foraminifera as bio-monitors of trace metal pollution in marginal marine environments.
Afficher plus [+] Moins [-]Effect of historical residual hexachlorocyclohexanes and dichlorodiphenyltrichloroethane on bacterial communities in sediment core collected from an estuary in northeastern China by next-generation sequencing Texte intégral
2015
Guo, Jianguo | Zhao, Longhao | Lu, Weihong | Jia, Hongliang | Wang, Luo | Liu, Xianjie | Sun, Yeqing
In this study, we evaluate the influence of hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethane (DDT) on bacterial communities of sediment core from an estuary formed during the period of 1960–2011. Canonical correspondence analysis showed that o,p′-DDT, o,p′-DDD (mitotane), and depth had important influences on bacterial community distributions (p<0.05). Furthermore, our results found variance explained by all variables was 82.9%, while that by o,p′-DDD was 24.4%, and that of o,p′-DDT was 9.8%, indicating that o,p′-DDD had a greater influence on sediment-dwelling bacteria than o,p′-DDT. Also, bacterial diversity was affected and the Shannon index was significantly negatively correlated with total HCHs (r=−0.579, p<0.05) and total DDTs (r=−0.607, p<0.01), respectively. Furthermore, our results showed that Flavobacteria and Clostridia content can be considered an indicator of pollution of HCHs and DDTs in sediment core samples.
Afficher plus [+] Moins [-]Historical trend in heavy metal pollution in core sediments from the Masan Bay, Korea Texte intégral
2015
Cho, Jinhyung | Hyun, Sangmin | Han, J.-H. | Kim, Suhyun | Shin, Dong-Hyeok
The spatiotemporal distribution and their mass accumulation rate (MAR) of heavy metals were investigated to evaluate the time-dependent historical trends of heavy metal concentration. The three short cores used for this study were collected from the catchment area (MS-PC5, 60cm length), the central part (MS-PC4, 40cm length) and the offshore (MS-PC2, 60cm length) of the Masan Bay, Korea. The concentration of heavy metals (Co, Ni, Cu, Zn, Cr and Pb) in catchment area is as much as 1.5–2 times higher than central part of the Bay, and about 2 times higher than offshore area approximately. In particular, MAR of metals (Cu, Zn and Pb) show clear spatiotemporal variation, so that MAR’s of heavy metal may provide more accurate information in evaluating the degree of pollution. Temporally, the heavy metal concentration had been increased since the late 1970s, but it seems to decrease again since the 2004yr in catchment area. This may came from concentrated efforts for the government to reduce industrial waste release.
Afficher plus [+] Moins [-]Hydrophobic poly(alkoxysilane) organogels as sorbent material for oil spill cleanup Texte intégral
2015
Ozan Aydin, Gulsah | Bulbul Sonmez, Hayal
In this study, reusable poly(alkoxysilane) organogels with high absorption capacities were synthesized by the condensation of a cyclo aliphatic glycol (UNOXOL™) and altering the chain length of the alkyltriethoxysilanes. The structural and thermal properties of cross-linked poly(alkoxysilane) polymers were determined by FTIR, solid-state 13C and 29Si CPMAS NMR and TGA. The oil absorbency of poly(alkoxysilane)s was determined through oil absorption tests, absorption and desorption kinetics. Results showed that the highest oil absorbency capacities were found to be 295% for hexane, 389% for euro diesel, 428% for crude oil, 652% for gasoline, 792% for benzene, 792% for toluene, 868% for tetrahydrofuran, and 1060% for dichloromethane for the poly(alkoxysilane) gels based on UNOXOL™ and dodecyltriethoxysilane. Owing to their hydrophobic structure, the poly(alkoxysilane) organogels can selectively absorb crude oil from water. The reusability of the absorbents was quantitatively investigated, demonstrating that absorbents can be used effectively at least nine times.
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