خيارات البحث
النتائج 1161 - 1170 من 3,208
Assessment of sediment contamination and sampling design in Savona Harbour, Italy النص الكامل
2015
Paladino, Ombretta | Massabò, Marco | Fissore, Francesca | Moranda, Arianna
A method for assessing environmental contamination in harbour sediments and designing the forthcoming monitoring activities in enlarged coastal ecosystems is proposed herein. The method is based on coupling principal component analysis of previous sampling campaigns with a discrete optimisation of a value for money function. The objective function represents the utility derived for every sum of money spent in sampling and chemical analysis. The method was then used to assess actual contamination and found to be well suited for reducing the number of chemicals to be searched during extended monitoring activities and identifying the possible sources of contamination. Data collected in Savona Harbour (Porto Vado), Italy, where construction of a new terminal construction is planned, were used to illustrate the procedure. 23 chemicals were searched for within a total of 213 samples in 68 sampling points during three monitoring campaigns. These data were used to test the procedure. Subsequently, 28 chemicals were searched for within 14 samples in 10 sampling points and collected data were used to evaluate the experimental error and to validate the proposed procedure.
اظهر المزيد [+] اقل [-]Accumulation and distribution of trace metals within soils and the austral cordgrass Spartina densiflora in a Patagonian salt marsh النص الكامل
2015
Idaszkin, Yanina L. | Lancelotti, Julio L. | Bouza, Pablo J. | Marcovecchio, Jorge E.
Concentrations of Cd, Cu, Fe, Pb, and Zn were determined in soils and in below- and above-ground structures of Spartina densiflora in a Patagonian salt marsh (San Antonio, Río Negro, Argentina). Also, the relationship between trace metal concentrations in soils and plants was investigated to improve our knowledge regarding the ability of this plant species to take up and accumulate trace metals from the soil. Our results indicate that, within the studied salt marsh, soil trace metal concentrations follow a decreasing concentration gradient toward the sea. They show moderate pollution and a potentially negative biological effect in one site of the salt marsh. While below-ground structures reflect the soil metal concentration pattern, this is not so evident in above-ground concentrations. Also, S. densiflora is able to absorb a limited amount of metals present in the soil, the soil bioaccumulation factor being lower in sites where soil metal concentration is higher.
اظهر المزيد [+] اقل [-]Antibiotics in typical marine aquaculture farms surrounding Hailing Island, South China: Occurrence, bioaccumulation and human dietary exposure النص الكامل
2015
Chen, Hui | Liu, Shan | Xu, Xiang-Rong | Liu, Shuang-Shuang | Zhou, Guang-Jie | Sun, Kai-Feng | Zhao, Jian-Liang | Ying, Guang-Guo
The occurrence, bioaccumulation, and human dietary exposure via seafood consumption of 37 antibiotics in six typical marine aquaculture farms surrounding Hailing Island, South China were investigated in this study. Sulfamethoxazole, salinomycin and trimethoprim were widely detected in the water samples (0.4–36.9ng/L), while oxytetracycline was the predominant antibiotic in the water samples of shrimp larvae pond. Enrofloxacin was widely detected in the feed samples (16.6–31.8ng/g) and erythromycin–H2O was the most frequently detected antibiotic in the sediment samples (0.8–4.8ng/g). Erythromycin–H2O was the dominant antibiotic in the adult Fenneropenaeus penicillatus with concentrations ranging from 2498 to 15,090ng/g. In addition, trimethoprim was found to be bioaccumulative in young Lutjanus russelli with a median bioaccumulation factor of 6488L/kg. Based on daily intake estimation, the erythromycin–H2O in adult F. penicillatus presented a potential risk to human safety.
اظهر المزيد [+] اقل [-]Spatial and vertical distributions of heavy metals and their potential toxicity levels in various beach sediments from high-background-radiation area, Kerala, India النص الكامل
2015
Suresh, G. | Ramasamy, V. | Sundarrajan, M. | Paramasivam, K.
The spatial and vertical distribution of heavy metals and the sediment characteristics of beaches in Kerala, India (the upper surface sediments and the first, second and third one-foot-thick strata) were assessed in this study. The concentrations of most of the studied metals were highest at sampling site S1 (Cochin). The measured concentrations were compared with background and toxicological reference values. The results show that definite adverse biological effects are possible at most of the sampling sites due to the high Pb levels. Three different indexes were calculated to investigate the potential toxicity level. Most of the studied metals and all calculated indexes were highest in the third foot of sediment. Multivariate statistical analyses were performed and suggested that particular heavy metals, e.g., Pb, Cd, Cr and Ni, may represent contamination from a common source. The Cd and Pb concentrations and all the calculated index values show a relationship with the content of organic matter. The results of the present study suggest the recommendation that a systematic analysis is needed to monitor heavy metal levels in the studied area.
اظهر المزيد [+] اقل [-]Evaluation of the boundary condition influence on PAH concentrations in the water column during the sediment dredging of a port النص الكامل
2015
Cutroneo, L. | Castellano, M. | Carbone, C. | Consani, S. | Gaino, F. | Tucci, S. | Magrì, S. | Povero, P. | Bertolotto, R.M. | Canepa, G. | Capello, M.
The mobilisation of sediments and related contaminants connected to dredging activities is one of the most critical issues to the environmental risk and exposure assessment of a dredging project. The aim of this paper was an investigation of the mobilisation of polycyclic aromatic hydrocarbons (PAHs) due to the dredging of the Port of Genoa (Italy) to identify the temporal and spatial extent of the contaminant transport, and the influence of the dredging and the boundary conditions on it. The results showed relatively low background PAH concentrations in the water column and confirmed the dredging as the primary rising factor of concentrations in the water column, but also showed a complex scenario in which the different environmental and dredging factors forced the concentrations at different levels and moments. The post dredging phase showed PAH values close to the background conditions and the concentrations remained relatively high only for a few PAHs.
اظهر المزيد [+] اقل [-]Radiative implication of a haze event over Eastern India النص الكامل
2015
Jose, Subin | Gharai, Biswadip | Bhavani Kumar, Y. | Narasimha Rao, Pamaraju Venkata
Aerosol haze degrades visibility by the process of absorption and scattering of aerosols. In the present study an attempt has been made to characterize the physical and optical properties of aerosols during a haze event on 29 March 2012 and assess its implication on radiative forcing. In this context representative clear (2 March 2012) and normal (19 March 2012) days were identified in terms of their Aerosol Optical Depth (AOD) loading over Hyderabad. On the hazy day, a huge spread of haze was observed over the eastern part of India by MODerate resolution Imaging Spectroradiometer (MODIS) on board Terra satellite which is represented by high Aerosol Optical Depth at 550nm. In-situ observations on hazy day showed an enhancement of columnar AOD500 respectively by 4.5 and 1.8 fold in comparison to clear and normal days. Significant increase in the scattering coefficient and a moderate enhancement of Single Scattering Albedo (SSA) are observed on hazy day compared to normal day. Study also showed that Diffuse-to-Direct- beam irradiance Ratio (DDR) had increased 4.5 times at 496.6nm spectral band on hazy day. LIDAR (LIght Detection And Ranging) observations on hazy night showed a threefold increase in aerosol backscattering below the Atmospheric Boundary Layer (ABL) compared to normal representative night. The hazy day is characterized by large negative surface forcing (−87.82W m−2) when compared to normal day (−53.90W m−2). A large positive enhancement of atmospheric forcing of 30.56W m−2 is observed on hazy day compared to normal day.
اظهر المزيد [+] اقل [-]Spatial distribution and transport patterns of NO2 in the Tijuana – San Diego area النص الكامل
2015
Rivera, Claudia | Stremme, Wolfgang | Barrera, Hugo | Friedrich, Martina M. | Grutter, Michel | Garcia–Yee, Jose | Torres–Jardon, Ricardo | Ruiz–Suarez, Luis Gerardo
The atmospheric composition of the San Diego – Tijuana border is affected by transport of air pollutants between both regions and in both directions. In this study we show NO2 transport events identified during Cal–Mex 2010 field experiment at two different ground sites, located one downwind of the other. This field campaign was designed to overlap with the closing weeks of CalNex project to observe trans–boundary pollution transport in this area. The measurements showed a clear dispersion pattern of NO2 towards the east–southeast on several occasions during the field experiment. Additionally, the NO2 column distribution above the Tijuana – San Diego region was reconstructed from the OMI satellite data product, and a cluster analysis with the corresponding meteorological data was performed to identify four distinct wind patterns yielding different NO2 distribution maps and detecting dominant wind patterns in this region, either towards the E–SE or E–NE approximately 86% of the time.
اظهر المزيد [+] اقل [-]Assessment of micronuclei induction in peripheral blood and gill cells of some fish species from Aliağa Bay Turkey النص الكامل
2015
Çakal Arslan, Özlem | Boyacioğlu, Meltem | Parlak, Hatice | Katalay, Selma | Karaaslan, Muhammet Ali
The aim of this paper was to assess the biological damages in fish caused by various mutagenic agents present in polluted waters of Aliağa Bay. For this purpose, micronuclei (MN) test was performed using peripheral erythrocytes and gill cells of different fish specimens caught from both polluted and relatively clean sites from Aliağa Bay (Turkey). Micronuclei tests is a system of mutagenicity testing used for determining changes in DNA fragments such as micronuclei in the cytoplasm of interphase cells caused by the pollution and chemicals in the environment. Thus, it was attempted to determine whether pollution affected the erythrocytes and gills of fish living in Aliağa Bay at the level of DNA by the means of micronuclei (MN) test. According to the results of present study, frequency of MN was found at high level in polluted site. In conclusion, this study indicates that the micronuclei test gives sensitive results in monitoring the pollution, especially the pollution of harbor, and thus it might be used as standard method in regularly monitoring pollution of coastal ecosystem.
اظهر المزيد [+] اقل [-]The sub-cellular fate of mercury in the liver of wild mullets (Liza aurata) – Contribution to the understanding of metal-induced cellular toxicity النص الكامل
2015
Araújo, Olinda | Pereira, Patrícia | Cesário, Rute | Pacheco, Mario | Raimundo, Joana
Mercury is a recognized harmful pollutant in aquatic systems but still little is known about its sub-cellular partitioning in wild fish. Mercury concentrations in liver homogenate (whole organ load) and in six sub-cellular compartments were determined in wild Liza aurata from two areas – contaminated (LAR) and reference. Water and sediment contamination was also assessed. Fish from LAR displayed higher total mercury (tHg) organ load as well as in sub-cellular compartments than those from the reference area, reflecting environmental differences. However, spatial differences in percentage of tHg were only observed for mitochondria (Mit) and lysosomes plus microsomes (Lys+Mic). At LAR, Lys+Mic exhibited higher levels of tHg than the other fractions. Interestingly, tHg in Mit, granules (Gran) and heat-denaturable proteins was linearly correlated with the whole organ. Low tHg concentrations in heat stable proteins and Gran suggests that accumulated levels might be below the physiological threshold to activate those detoxification fractions.
اظهر المزيد [+] اقل [-]Distribution of heavy metals in the coastal area of Abu Dhabi in the United Arab Emirates النص الكامل
2015
Al Rashdi, Saeed | Arabi, Alya A. | Howari, Fares M. | Siad, Abdi
Distribution of heavy metals in the coastal area of Abu Dhabi in the United Arab Emirates النص الكامل
2015
Al Rashdi, Saeed | Arabi, Alya A. | Howari, Fares M. | Siad, Abdi
Fifty-seven sediment samples were collected from Abu Dhabi coastal area, United Arab Emirates (UAE). The concentrations of heavy metals including antimony, arsenic, barium, cadmium, cobalt, copper, mercury, lead, molybdenum, nickel and zinc were obtained using Inductively Coupled Plasma–Mass Spectroscopy (ICP–MS) and X-ray fluorescence. Heavy metal contaminations in Abu Dhabi had increased since 2004. Nevertheless, the enrichment factors, geoaccumulation indices and the pollution load index of 0.3 showed no pollution with any of the measured metals except arsenic.
اظهر المزيد [+] اقل [-]Distribution of heavy metals in the coastal area of Abu Dhabi in the United Arab Emirates النص الكامل
Al Rashdi, Saeed | Arabi, Alya A. | Howari, Fares M. | Siad, Abdi
© 2015 Elsevier Ltd. Fifty-seven sediment samples were collected from Abu Dhabi coastal area, United Arab Emirates (UAE). The concentrations of heavy metals including antimony, arsenic, barium, cadmium, cobalt, copper, mercury, lead, molybdenum, nickel and zinc were obtained using Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) and X-ray fluorescence. Heavy metal contaminations in Abu Dhabi had increased since 2004. Nevertheless, the enrichment factors, geoaccumulation indices and the pollution load index of 0.3 showed no pollution with any of the measured metals except arsenic.
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