Уточнить поиск
Результаты 621-630 из 3,207
The amount and accumulation rate of plastic debris on marshes and beaches on the Georgia coast Полный текст
2015
Lee, Richard F. | Sanders, Dorothea P.
The amount and accumulation rate of plastic debris at 20 sites along the Georgia coast were prepared using data reported by a number of volunteer organizations. The amount of plastic debris at highly visited barrier island beaches and estuarine marshes ranged from 300 to >1000kg. Relatively large amount of plastics (180–500kg) were found on less visited barrier island beaches, i.e. Blackbeard, Ossabaw and Cumberland Islands. A follow up monthly or quarterly collection study was carried out on two of the sites, a barrier beach and estuarine marsh, to determine accumulation rate in 8000m2 areas. Accumulation rates ranged from 0.18 to 1.28kg/30days–8000m2 on the barrier island beach and from 0.6 to 1.61kg/30days–8000m2 at the estuarine marsh site. The major type of plastics, e.g. bottles, food wrappers, plastic fragments, was highly variable at different seasons and sites. The authors recommend consideration of a standardization in reporting plastic debris, with respect to quantitation of debris and sample area.
Показать больше [+] Меньше [-]Ingestion of microplastics by commercial fish off the Portuguese coast Полный текст
2015
Neves, Diogo | Sobral, Paula | Ferreira, Joana Lia | Pereira, Tânia
The digestive tract contents of 263 individuals from 26 species of commercial fish were examined for microplastics. These were found in 17 species, corresponding to 19.8% of the fish of which 32.7% had ingested more than one microplastic. Of all the fish that ingested microplastics, 63.5% was benthic and 36.5% pelagic species. A total of 73 microplastics were recorded, 48 (65.8%) being fibres and 25 (34.2%) being fragments. Polymers were polypropylene, polyethylene, alkyd resin, rayon, polyester, nylon and acrylic. The mean of ingested microplastics was 0.27±0.63 per fish, (n=263). Pelagic fish ingested more particles and benthic fish ingested more fibres, but no significant differences were found. Fish with the highest number of microplastics were from the mouth of the Tagus river.Scomber japonicus registered the highest mean of ingested microplastics, suggesting its potential as indicator species to monitor and investigate trends in ingested litter, in the MSFD marine regions.
Показать больше [+] Меньше [-]Glyphosate and AMPA in the estuaries of the Baltic Sea method optimization and field study Полный текст
2015
Skeff, Wael | Neumann, Christine | Schulz-Bull, Detlef E.
Water samples from ten German Baltic estuaries were collected in 2012 in order to study the presence of the herbicide glyphosate, its primary metabolite AMPA and their potential transport to the marine environment. For the analyses an LC–MS/MS based analytical method after derivatization with FMOC-Cl was optimized and validated for marine water samples. All investigated estuarine stations were contaminated with AMPA and nine of them also with glyphosate. Concentration ranges observed were 28 to 1690ng/L and 45 to 4156ng/L for glyphosate and AMPA, respectively with strong spatial and temporal fluctuations. Both contaminants were found at inbound sampling sites in the stream Muehlenfliess and concentrations decreased along the salinity gradient to the estuaries of the Baltic Sea. The data obtained in this study clearly depict the transport of glyphosate and AMPA to the Baltic Sea. Hence, detailed fate and risk assessment for both contaminants in marine environments are required.
Показать больше [+] Меньше [-]Daily variations in pathogenic bacterial populations in a monsoon influenced tropical environment Полный текст
2015
Khandeparker, Lidita | Anil, Arga Chandrashekar | Naik, Sneha D. | Gaonkar, Chetan C.
Changing climatic conditions have influenced the monsoon pattern in recent years. Variations in bacterial population in one such tropical environment were observed everyday over two years and point out intra and inter annual changes driven by the intensity of rainfall. Vibrio spp. were abundant during the monsoon and so were faecal coliforms. Vibrio alginolyticus were negatively influenced by nitrate, whereas, silicate and rainfall positively influenced Vibrio parahaemolyticus numbers. It is also known that pathogenic bacteria are associated with the plankton. Changes in the abundance of plankton, which are governed mainly by environmental changes, could be responsible for variation in pathogenic bacterial abundance during monsoon, other than the land runoff due to precipitation and influx of fresh water.
Показать больше [+] Меньше [-]Assessing the ecological quality status of a temperate urban estuary by means of benthic biotic indices Полный текст
2015
Hutton, M. | Venturini, N. | García-Rodríguez, F. | Brugnoli, E. | Muniz, P.
Benthic indices are commonly used tools for assessing the environmental quality, because they represent a simple source of scientific information. However, their performance could vary depending on the application area and perturbation types, thus they should be tested before used in other remote geographic regions. This study aims to test the use of some of the most widely common benthic biotic indices for assessing the environmental quality of Montevideo’s coastal zone at a seasonal scale against many physicochemical variables. From all the evaluated indices, AMBI appears to be the most suitable one to assess the environmental quality. The study also allowed us to infer the most relevant physicochemical variables: protein, lipid and heavy metal sediment concentration. Additionally, site-specific threshold effect levels for heavy metals and biopolymers were established, which appear to be useful to determine tolerable levels of such stressors in future assessments or monitoring programs for the study area.
Показать больше [+] Меньше [-]Plastic and metal ingestion in three species of coastal waterfowl wintering in Atlantic Canada Полный текст
2015
English, Matthew D. | Robertson, Gregory J. | Avery-Gomm, Stephanie | Pirie-Hay, Donald | Roul, Sheena | Ryan, Pierre C. | Wilhelm, Sabina I. | Mallory, Mark L.
Relatively little attention has been paid to the occurrence of anthropogenic debris found in coastal species, especially waterfowl. We examined the incidence of ingested plastic and metal in three waterfowl species wintering in Atlantic Canada: American black ducks (Anas rubripes) and mallards (A. platyrhynchos), two species that use marine and freshwater coastal habitats for foraging in the winter, and common eider (Somateria mollissima), a coastal marine species that feeds on intertidal and subtidal benthic organisms. Plastic was found in the stomachs of 46.1% (6/13) of mallards and 6.9% (6/87) of black ducks, the first report of ingested anthropogenic debris in these species, while 2.1% (1/48) of eider stomachs contained plastic. Metal was found in the stomachs of 30.8% (4/13) of mallards, 2.3% (2/87) of black ducks, and in 2.1% (1/48) of eiders. Our results indicate that species using coastal marine and freshwater environments are exposed to and ingest anthropogenic debris.
Показать больше [+] Меньше [-]Environmental radionuclides in a coastal wetland of the Southern Laizhou Bay, China Полный текст
2015
Wang, Qidong | Song, Jinming | Li, Xuegang | Yuan, Huamao | Li, Ning | Cao, Lei
The radioactivity concentration of 238U, 232Th, 226Ra, 40K, and 137Cs in soil samples collected in a coastal wetland of the Southern Laizhou Bay, China were measured. Mean activity concentrations were 54.4±11.7, 57.9±9.7, 28.6±4.3, 542±21, and 10.2±2.9Bqkg−1 dry weight for 238U, 232Th, 226Ra, 40K and 137Cs, respectively. Statistical analyses suggested significant correlations between clay content and 40K as well as 137Cs. The radium equivalent activity, the absorbed dose rate in the air at 1m above the ground surface, and the external hazard index were calculated. The result showed that the radioactivity level in the wetland was in normal range. But sites along the river tended to have higher radiological hazard indexes. The vertical distributions of radionuclides in profiles illustrated some phenomena, such as vertical transport of 238U, disequilibrium between 238U and 226Ra, and change in material sources.
Показать больше [+] Меньше [-]Biotope map of the German Baltic Sea Полный текст
2015
Schiele, Kerstin S. | Därr, Alexander | Zettler, Michael L. | Friedland, René | Tauber, Franz | von Weber, Mario | Voss, Joachim
Full-coverage maps on the distribution of marine biotopes are a necessary basis for Nature Conservation and Marine Spatial Planning. Yet biotope maps do not exist in many regions. We are generating the first full-coverage biotope map for the German Baltic Sea according to the HELCOM Underwater biotope and habitat classification system (HUB). Species distribution modelling is applied to create full-coverage spatial information of biological features. The results of biomass modelling of twelve target taxa and presence/absence modelling of three target taxa enabled the identification of biological levels up to HUB level 6. Environmental data on bathymetry, light penetration depth and substrate are used to identify habitat levels. HUB biotope levels were combined with HUB habitat levels to create a biotope map. Altogether, 68 HUB biotopes are identified in the German Baltic Sea. The new biotope map combining substrate characteristics and biological communities will facilitate marine management in the area.
Показать больше [+] Меньше [-]Modelling the fate of micropollutants in the marine environment using passive sampling Полный текст
2015
Claessens, Michiel | De Laender, Frederik | Monteyne, Els | Roose, Patrick | Janssen, Colin R.
Polydimethylsiloxane sheets were used to determine freely dissolved concentrations (Cdiss) of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the Belgian coastal zone. Equilibrium models were used to predict the whole water concentrations (Cww) of these compounds as well as their concentrations in sediment, suspended particulate matter (SPM) and biota. In general, contaminant concentrations were predicted well for whole water and biota. Cww was increasingly underpredicted as Koc increased, possibly because of the presence of black carbon. Concentrations in biota were overestimated by the equilibrium approach when logKow exceeded 6.5, suggesting an increasing role of transformation processes. Concentrations of PAHs and PCBs in sediment and SPM were consistently underpredicted although a good correlation between measured and predicted values was observed. This was potentially due to the use of experimental Koc values which have been found to underestimate partitioning of hydrophobic substances to sediment in field studies.
Показать больше [+] Меньше [-]Relationship of MISR component AODs with black carbon and other ground monitored particulate matter composition Полный текст
2015
Zeeshan, Muhammad | Nguyễn, Thị Kim Oanh
This study assessed the relationship between the satellite Aerosol Optical Depths (AODs) and the ground monitored concentrations of particulate matter (PM) mass and its major constituents (black carbon–BC, organic carbon–OC, sulfates and nitrates), respectively. Both component AOD and total AOD products of Multi–angel Imaging Spectro Radiometer (MISR) were used for comparison along with the AOD product of the Moderate Resolution Imaging Spectroradiometer (MODIS). The ground PM data available during the period from 2004 to 2010 at the Asian Institute of Technology (AIT), a suburb site of the Bangkok Metropolitan Region, was used. MODIS and MISR AODs were validated against Sun photometer AOD, monitored at the Pimai AERONET station which showed strong linear regression with high R2 values of 0.87 and 0.92, respectively. The correlation coefficients between MODIS and MISR AODs and PM mass concentrations, respectively, were improved after exclusion of observations with cloud cover above 3/10. The R values (square root of determination coefficient R2) for linear relationships between PM10 and MODIS AOD were accordingly increased from 0.33 to 0.58 for MODIS AOD and from 0.25 to 0.54 for MISR AOD, while those for PM2.5 were improved from 0.30 to 0.55 for MODIS AOD and from 0.31 to 0.43 for MISR AOD. The stepwise regression was conducted to analyze the relationship between MISR component AODs and the mass concentration of PM10 and PM2.5, respectively, as well as their constituents. Higher R values were obtained for all regression equations using MISR component AODs as compared to those using total AOD. MISR component AODs showed higher capacity for monitoring daily BC (R=0.74–0.75) and sulfates (R=0.72), as compared to nitrates (R=0.52–0.54) and hourly OC (R=0.47). The potential of MISR component AODs for ambient PM monitoring should be explored and applied in other regions.
Показать больше [+] Меньше [-]