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The risk assessment of heavy metals in Futian mangrove forest sediment in Shenzhen Bay (South China) based on SEM–AVS analysis
2015
Chai, Minwei | Shen, Xiaoxue | Li, Ruili | Qiu, Guoyu
The risks of heavy metal in Futian mangrove forest sediment were assessed using the acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) methods. The results indicated that AVS distributions were more variable than the SEM distributions at all 16 sampling sites. The positive correlation between AVS and SEM indicated that their similar formative and existing conditions and that AVS acted as an important carrier for SEM. The major SEM component was Zn (69.7.3–94.2%), whereas the Cd contribution (the most toxic metal present) to SEM was no more than 1%. The possible adverse effects caused by heavy metals at ten sampling sites may be due to higher levels of SEMs, rather than AVSs. The total organic carbon (TOC) was an important metal-binding phase in the sediments. Taking into account the TOC concentration, there were no adverse effects due to heavy metals in any of the Futian mangrove forest sediments.
Mostrar más [+] Menos [-]Integrated use of biomarkers and condition indices in mussels (Mytilus galloprovincialis) for monitoring pollution and development of biomarker index to assess the potential toxic of coastal sites
2015
Benali, Imene | Boutiba, Zitouni | Merabet, Amina | Chèvre, Nathalie
In this study, we are interested in spatial and temporal variations of the biological and physiological responses of mussels collected from contrasting marine sites regarding their levels of pollution. We measured both the conditions indices and the enzymatic biomarker expression: acetylcholinesterase (AChE), catalase (CAT) and glutathione S-transferase (GST) activity. The enzymatic biomarkers were chosen because they respond to environmental stress. Results show a significant interactions between biomarker variations and conditions indices in the industrial harbor site throughout the seasons. But no significant changes in the reference site. Furthermore, we classified the sites along the seasons according to their potential ecotoxicity, calculated based on the sum of the normalised values of the biomarkers. The results show a very high biomarker index in the impacted site with irregular changes between seasons. This biomarker index is therefore a valuable tool that could be used to classify the toxic potential of coastal sites.
Mostrar más [+] Menos [-]Geochemical partitioning of Cu and Ni in mangrove sediments: Relationships with their bioavailability
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.
Mostrar más [+] Menos [-]Modelling the transport and accumulation of floating marine debris in the Mediterranean basin
2015
Mansui, J. | Molcard, A. | Ourmières, Y.
In the era of plastic and global environmental issues, when large garbage patches have been observed in the main oceanic basins, this work is the first attempt to explore the possibility that similar permanent accumulation structures may exist in the Mediterranean Sea. The questions addressed in this work are: can the general circulation, with its sub-basins scale gyres and mesoscale instabilities, foster the concentration of floating items in some regions? Where are the more likely coastal zones impacted from open ocean sources?Multi-annual simulations of advected surface passive debris depict the Tyrrhenian Sea, the north-western Mediterranean sub-basin and the Gulf of Sirte as possible retention areas. The western Mediterranean coasts present very low coastal impact, while the coastal strip from Tunisia to Syria appears as the favourite destination. No permanent structure able to retain floating items in the long-term were found, as the basin circulation variability brings sufficient anomalies.
Mostrar más [+] Menos [-]Marine litter in bottom trawls off the Portuguese coast
2015
Neves, Diogo | Sobral, Paula | Pereira, Tânia
Benthic marine litter along the Portuguese coast, was recorded in 14 trips on stern trawlers covering a distance of 2117km and an area of 56.2km2, average depth range 90–349m. 2034 items of marine litter were registered, 76% were plastics and 38.6% were originated from fishing related activities. Plastic was present in all the trawls and had the highest average density of all litter categories, 50itemskm−2.The highest density of marine litter (178.9±64.0itemskm−2) was found in the proximity of the Tagus river mouth, probably related to the high population density in the Lisbon metropolitan area.This study highlights the need to raise fishermen awareness for the adoption of good environmental practices that will contribute to the reduction of marine litter.
Mostrar más [+] Menos [-]Biodegradation of HDPE by Aspergillus spp. from marine ecosystem of Gulf of Mannar, India
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.
Mostrar más [+] Menos [-]Characteristics of marine debris that entangle Australian fur seals (Arctocephalus pusillus doriferus) in southern Australia
2015
Lawson, T.J. | Wilcox, Chris | Johns, Karen | Dann, P. | Hardesty, Britta Denise
Marine debris is a global issue that can have devastating impacts on marine mammals. To understand the types of materials that result in entanglement and thus the potential impact of entangling items on marine wildlife, we analysed data collected from items in which Australian fur seals had been entangled in southern Victoria, Australia over a 15year period. From 1997 to 2012, 138 entangling items were removed from seals. The majority of these entanglements were plastic twine or rope, and seals were entangled in green items more than in any other colour. In general, younger seals were more likely to be entangled than adults. Understanding the effects of marine debris entanglement on the Australian fur seal population can lead to more effective management of the sources of debris and the wildlife that interact with it.
Mostrar más [+] Menos [-]Levels and spatial distribution of perfluoroalkyl substances in China Liaodong Bay basin with concentrated fluorine industry parks
2015
Chen, Hong | Zhang, Can | Han, Jianbo | Sun, Ruijun | Kong, Xiangyun | Wang, Xiaomeng | He, Xin
Eighteen different perfluoroalkyl substances (PFASs) were investigated in 35 river water samples and 34 sediment samples collected from rivers in the Liaodong Bay basin containing two fluorine industry parks. Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) were the predominant PFASs in freshwater, with median concentrations of 26.5ng/L and 1.87ng/L, respectively. However, perfluorobutane sulfonate (PFBS) had the highest maximum concentration (up to 124.1ng/L, approximately two orders of magnitude higher) in water at a site which is the nearest to the industrial source of PFASs. Total PFASs in water at this site were also the highest. In contrast, PFOA and perfluorooctadecanoate (PFOcDA) were the most abundant PFASs in sediment, with median concentrations of 1.19ng/g and 0.35ng/g, respectively. Total PFAS concentrations in sediment from the site near to the industrial park were significantly higher than the other rivers. Mass loading of total PFASs from the rivers flowing into Liaodong Bay was estimated to be 506kg/year.
Mostrar más [+] Menos [-]Underwater noise assessment in the Gulf of Trieste (Northern Adriatic Sea, Italy) using an MSFD approach
2015
Codarin, Antonio | Picciulin, Marta
In the marine environment, underwater noise is one of the most widespread input of man-made energy. Recently, the European Commission has stressed the necessity of establishing threshold levels as a target for the descriptor 11.2.1 “Continuous low frequency sounds” in the Marine Strategy Framework Directive (MSFD). In 2012, a monthly underwater noise monitoring programme was conducted in the Gulf of Trieste (Northern Adriatic Sea, Italy); the collected acoustic samples (frequency range: 10–20,000Hz) were analysed in the 1/3 octave bands. The stations have been further clustered following the 63 and 125Hz bands noise levels. Average SPL levels resulted similar to those previously computed for proximate areas, indicating that the Adriatic Sea sub-region experiences high noise pressure in the marine waters. In its turn this claims for a scientific and technical international cooperation, as requested by the EU programme. No seasonal variation in local noise levels has been found.
Mostrar más [+] Menos [-]Influence of atmospheric circulation patterns on urban air quality during the winter
2015
Grundstrom, Maria | Tang, Lin | Hallquist, Mattias | Nguyen, Hung | Chen, Deliang | Pleijel, Håkan
Relationships between urban nitrogen dioxide (NO2) and atmospheric circulation at two spatial scales were studied for Southern Sweden. Lamb Weather Types (LWT) describe the circulation (scale: thousands of kilometers) including non–directional (cyclonic and anticyclonic) and directional types depending on the wind direction. LWTs with low wind speeds (anticyclonic, NW and N) were associated with strongly elevated [NO2], between 46–52% of the daily averages of NO2 exceeded the 60μg m−3 air quality standard (AQS) when occurring during these LWTs. The lowest fractions of exceedances of NO2 AQS were generally observed for LWTs E, S, SW and W. A larger scale circulation (several thousands of kilometers) was represented by the North Atlantic Oscillation (NAO) affecting meteorology over middle and high latitudes in the Northern Hemisphere. While a negative NAO index (NAOI) favors stagnant high pressure weather over Northern Europe, a positive NAOI is often associated with windy conditions. High [NO2] was found to be frequent under negative NAOI. Additionally, larger fractions of exceedances of NO2 AQS were observed for the majority of LWTs occurring at negative NAOI. It’s concluded that both LWTs and NAOI had partly independent effects on the urban air quality in a North European city. These circulation indices can be useful tools for air pollution risk assessment and forecasting.
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