خيارات البحث
النتائج 1191 - 1200 من 4,291
Accumulation of endocrine disrupting chemicals in the liver of Diplodus sargus sargus in Torre Guaceto Natural Reserve
2017
Rizzo, Daniela | Pennetta, Antonio | De Benedetto, Giuseppe E.
Studies on the quality of marine environments in Italy have traditionally favoured heavily impacted areas, such as harbours and industrial areas, while there are few investigations aimed at the evaluation of the presence of organic pollutants in the areas of marine reserve. The aim of this study was to determine endocrine-disrupting compounds (EDCs) in the liver of white seabreams (Diplodus sargus sargus) from the Natural Reserve of Torre Guaceto, Italy. Among EDCs, alkyl-phenols 2,6-DTBP, 2,4-DTBP, OP, and BPA were identified and quantified. The mean concentration of 2,6-DTBP, 2,4-DTBP, OP, and BPA were 2.2, 2.0, 1.2 and 3.6ng/g of liver, respectively, confirming the occurrence and transfer of these organic pollutants in the food web of marine organisms in marine reserves.
اظهر المزيد [+] اقل [-]Bio-effect-monitoring of long-term thermal wastes on the oyster, Crassostrea gigas, using heat shock proteins
2017
We bio-monitored the stress of oyster, Crassostrea gigas, for possible long term effects of thermal waste from a power plant. The expression level of its heat shock proteins (HSPs) was measured by real time-reverse transcript PCR along with their density and growth in the field. Oyster size varied in a distance dependent pattern. Physics modeling for evaluation of spreading of the thermal effluent revealed that station A is affected by the thermal effluents abundance, and the size of C. gigas showed a negative relationship with distance to the power plant. The abundance and size of C. gigas were smallest at station A, which was closest to the thermal effluent outlet. The kinetics of changes in the hsp70 and hsp90 mRNA levels in the mantle of C. gigas were also investigated. Regardless of the higher expression level of hsp70 mRNA than hsp90, both hsp70 and hsp90 mRNA levels were significantly higher at station A. The expression levels decreased inversely with distance from the thermal effluent outlet, with expression of hsp70 mRNA at station A being approximately 7-fold higher than at station B and 15-fold higher than at station C. Similarly, expression of hsp90 mRNA at station A was approximately 14-fold higher than at station B and 22-fold higher than at station C. The present findings provide new insights on biological correlation among the growth of individuals and population size and the molecular index in C. gigas following thermal effects.
اظهر المزيد [+] اقل [-]Management and environmental risk study of the physicochemical parameters of ballast water
2017
Shipping is a vital industry for the global economy. Stability of ships, provided by ballast water, is a crucial factor for cargo loading and unloading processes. Ballast water treatment has practical significance in terms of environmental issues, ecosystem, and human health, because ships discharge this water into the environment before loading their cargos. This study reviews the common methods for ballast water management – exchange, heating, filtration, ultrasonic treatment, ultraviolet irradiation, chemicals, and gas supersaturation – to select the best one. This study compares water temperature, salinity, dissolved oxygen, polycyclic aromatic hydrocarbons (PAHs), and heavy metals (Co, Cr, Ni, Pb) for ballast tanks of selected ships with the recipient port environment in the Persian Gulf as a case study. The exchange of ballast water in the ocean and/or its treatment on board to prevent inadvertent effects on the environment's physicochemical conditions is related to vessel characteristics, legislation, and the environmental condition. Ecological risk study showed that the salt content in ballast water is close to that of seawater, but the values of Cr (2.1mg/l) and Ni (0.029mg/l) in ballast water are higher than those in seawater (1 and 0.004mg/l, respectively).
اظهر المزيد [+] اقل [-]Geochemical markers of sedimentary organic matter in Todos os Santos Bay, Bahia – Brazil. Indicators of sources and preservation
2017
de Souza, José Roberto Bispo | do Rosário Zucchi, Maria | Costa, Alexandre Barreto | de Azevedo, Antonio Expedito Gomes | Spano, Saulo
Natural stable isotopes, such as carbon (C) and nitrogen (N), are modern tools to assess geochemical processes. C and N in organic matter can carry fingerprints of their hydrologic flows and sedimentary processes, including any anthropogenic modification on the natural system. This study focuses on the determination of aliphatic and polycyclic aromatic hydrocarbons and isotopic ratio in the sediment of Todos os Santos Bay (TSB). The isotopic results of the total organic matter indicate varied contribution marine and terrigenous. Typical rates of PAHs mainly indicate a pyrogenic source and mixture between pyrogenic and petrogenic sources. Typical ratios for the n-alkanes indicate the presence of petroleum hydrocarbons. The isotopic composition of n-alkanes suggests a mixture of sources, with the possible contribution of petrogenic.
اظهر المزيد [+] اقل [-]Uncovering hidden heterogeneity: Geo-statistical models illuminate the fine scale effects of boating infrastructure on sediment characteristics and contaminants
2017
Hedge, L.H. | Dafforn, K.A. | Simpson, S.L. | Johnston, E.L.
Infrastructure associated with coastal communities is likely to not only directly displace natural systems, but also leave environmental footprints' that stretch over multiple scales. Some coastal infrastructure will, there- fore, generate a hidden layer of habitat heterogeneity in sediment systems that is not immediately observable in classical impact assessment frameworks. We examine the hidden heterogeneity associated with one of the most ubiquitous coastal modifications; dense swing moorings fields. Using a model based geo-statistical framework we highlight the variation in sedimentology throughout mooring fields and reference locations. Moorings were correlated with patches of sediment with larger particle sizes, and associated metal(loid) concentrations in these patches were depressed. Our work highlights two important ideas i) mooring fields create a mosaic of habitat in which contamination decreases and grain sizes increase close to moorings, and ii) model- based frameworks provide an information rich, easy-to-interpret way to communicate complex analyses to stakeholders.
اظهر المزيد [+] اقل [-]Geochemical speciation, bioavailability and source identification of selected metals in surface sediments of the Southern Caspian Sea
2017
Bastami, Kazem Darvish | Neyestani, Mahmoud Reza | Esmaeilzadeh, Marjan | Haghparast, Sarah | Alavi, Camelia | Fathi, Sanaz | Nourbakhsh, Shahram | Shirzadi, Emam Ali | Parhizgar, Reyhane
Geochemical speciation of As, Cd, Co, Cr, Cu, Ni, Pb, V and Zn were determined in the surface sediments of the southern Caspian Sea. A five-step sequential extraction technique was used to determine the chemical forms of metals. Mean concentrations (ppm) of heavy metals were (mean±S.D.) As: 9.94±1.71, Cd: 0.87±0.23, Co: 14.85±2.80, Cr: 72.29±19.48, Cu: 18.91±4.48, Ni: 32.87±5.25, Pb: 12.48±3.22, V: 86.07±20.71 and Zn: 66.85±10.11. Among the metals, Cu, As, Pb and Zn exhibited relatively higher mobility, while Cd, Co, Cr, Ni and V were found mainly in the residual fractions. Cu and As showed the highest percentages in the exchangeable phase while Co and Cr had the lowest percentages in the phase. The Risk Assessment Code (RAC) values indicated that As, Cu and V had medium risk at some sampling sites. According to pollution load index (PLI), sediments from some sampling sites were polluted.
اظهر المزيد [+] اقل [-]Plastic debris and microplastics along the beaches of the Strait of Hormuz, Persian Gulf
2017
Naji, Abolfazl | Esmaili, Zinat | Khan, Farhan R
Currently little is known about the prevalence of plastics and microplastics (MPs) in the Persian Gulf. Five sampling stations were selected along the Strait of Hormuz (Iran) that exhibited different levels of industrialization and urbanization, and included a marine protected area. Debris was observed and sediments were collected for MPs extraction via fluidization/floatation methodology. The order of MP abundance (par/kg) generally reflected the level of anthropogenic activity: Bostanu (1258±291)>Gorsozan (122±23)>Khor-e-Yekshabeh (26±6)>Suru (14±4)>Khor-e-Azini (2±1). Across all sites fibers dominated (83%, 11% film, 6% fragments). FT-IR analysis showed polyethylene (PE), nylon, and PET (polyethylene terephthalate) were the commonly recovered polymers. Likely sources include beach debris, discarded fishing gear, and urban and industrial outflows that contain fibers from clothes. This study provides a ‘snapshot’ of MP pollution and longitudinal studies are required to fully understand plastic contamination in the region.
اظهر المزيد [+] اقل [-]Spatial and temporal variation of macro-, meso- and microplastic abundance on a remote coral island of the Maldives, Indian Ocean
2017
Imhof, Hannes K. | Sigl, Robert | Brauer, Emilia | Feyl, Sabine | Giesemann, Philipp | Klink, Saskia | Leupolz, Kathrin | Löder, Martin G.J. | Löschel, Lena A. | Missun, Jan | Muszynski, Sarah | Ramsperger, Anja F.R.M. | Schrank, Isabella | Speck, Susan | Steibl, Sebastian | Trotter, Benjamin | Winter, Isabel | Laforsch, Christian
Plastic debris is ubiquitous in the marine environment and the world's shores represent a major sink. However, knowledge about plastic abundance in remote areas is scarce. Therefore, plastic abundance was investigated on a small island of the Maldives. Plastic debris (>1mm) was sampled once in natural long-term accumulation zones at the north shore and at the high tide drift line of the south shore on seven consecutive days to quantify daily plastic accumulation. Reliable identification of plastic debris was ensured by FTIR spectroscopy. Despite the remoteness of the island a considerable amount of plastic debris was present. At both sites a high variability in plastic abundance on a spatial and temporal scale was observed, which may be best explained by environmental factors. In addition, our results show that snapshot sampling may deliver biased results and indicate that future monitoring programs should consider spatial and temporal variation of plastic deposition.
اظهر المزيد [+] اقل [-]Environmental Ground-Borne Noise and Vibration from Urban Light Rail Transportation During Construction and Operation
2017
Vogiatzis, Konstantinos E. | Kouroussis, Georges
Environmental vibration and ground-borne noise from light rail transport (LRT) networks consists a major impact on the urban environment. Since experiments are often difficult to obtain and to interpret especially for environmental vibration, designers and researchers generally resource numerical model to assess vibration levels and understand the complex mechanism of generation and propagation of ground vibration. In this paper, some highlights are provided on vehicle/track/soil modeling for railway-induced ground vibration, including the proper definitions of each of these subsystems. The nature of the wheel/rail interaction is also important, especially in urban area, so a case study demonstrates that local unevenness are important sources of vibrations. On the other hand, specialized prediction models and dose-response relationships for airborne rail noise during operation and construction phases of urban light rail transport networks (both underground and surficial) are needed to be evaluated, in order to quantify the impact of the technical characteristics of the noise source, the operation mode with emphasis to speed, the propagation, the implementation of quiet facades, and the number and distribution of high-level noise events. In the present paper, two distinct case studies are presented in order to emphasize the need and the necessity of using proper tools to predict, access, monitor, and evaluate the environmental impact of LRTs to the urban acoustic environment: (a) the new Brussels Regional Express Network and (b) the new Athens Metro Line 3 extension to Piraeus port in an underground tunnel (length 7.6 km).
اظهر المزيد [+] اقل [-]Reliability and utility of citizen science reef monitoring data collected by Reef Check Australia, 2002–2015
2017
Done, Terence | Roelfsema, Chris | Harvey, Andrew | Schuller, Laura | Hill, Jocelyn | Schläppy, Marie-Lise | Lea, Alexandra | Bauer-Civiello, Anne | Loder, Jennifer
Reef Check Australia (RCA) has collected data on benthic composition and cover at >70 sites along >1000km of Australia's Queensland coast from 2002 to 2015. This paper quantifies the accuracy, precision and power of RCA benthic composition data, to guide its application and interpretation. A simulation study established that the inherent accuracy of the Reef Check point sampling protocol is high (<±7% error absolute), in the range of estimates of benthic cover from 1% to 50%. A field study at three reef sites indicated that, despite minor observer- and deployment-related biases, the protocol does reliably document moderate ecological changes in coral communities. The error analyses were then used to guide the interpretation of inter-annual variability and long term trends at three study sites in RCA's major 2002–2015 data series for the Queensland coast.
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