نتایج جستجو برای: sediments

تعداد نتایج: 28437  

2005
Woei-Lih Jeng Chih-An Huh

Twelve surface sediments from the southern Okinawa Trough (OT) and nine surface sediments from a nearby river, the Lanyang River (LR), with high sediment discharge were analyzed for comparison of their aliphatic hydrocarbon distributions. Performing cluster analysis on all hydrocarbon data of LR and OT sediments showed that the two areas had a similarity level of only 0.15, meaning that they we...

2015
Anna Hanke Jasmine Berg Theresa Hargesheimer Halina E. Tegetmeyer Christine E. Sharp Marc Strous

In coastal marine sediments, denitrification and fermentation are important processes in the anaerobic decomposition of organic matter. Microbial communities performing these two processes were enriched from tidal marine sediments in replicated, long term chemostat incubations at 10 and 25°C. Whereas denitrification rates at 25°C were more or less stable over time, at 10°C denitrification activ...

Journal: :international journal of environmental research 2014
a. banas k. banas p. yang h.o. moser m.b.h. breese

x-ray absorption fine structure (xafs) spectroscopy was used to identify directly the metal speciation and local bonding environment of fe in sediments originated from dobczyce reservoir (poland); special attention was paid to analysis of samples collected from points situated at different distances from the land. the combination of traditional approach to data analysis as well as usage of mult...

Journal: :Marine pollution bulletin 2014
Parthasarathi Chakraborty P V Raghunadh Babu Krushna Vudamala Darwin Ramteke Kartheek Chennuri

This is the first study to describe distribution and speciation of Hg in coastal sediments from the central east coast of India. The concentrations of Hg in the studied sediments were found to be much lower than the Hg concentration recommended in coastal sediments by the United State Environmental Protection Agency and the Canadian Council of Ministers of the Environment for the protection of ...

ژورنال: علوم آب و خاک 2015
حسینی, خسرو, خیرخواهان, مهران,

Cohesive sediments have large specific surfaces which enable them to absorb other cohesive sediments and polar particles such as mud and sodium. Floccules form by joining these particles. The behavior of cohesive sediments in aquatic environments is completely different from that of granular sediments. Under certain value of shear stress, the structure formed from cohesive sediments is divided ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده علوم 1376

saluk mount is selected for devonian biostratigraphy. this area located at southwest of bojnurd. in this study three sections are selected and two sections, chahar-borj and tabar sections with a thickness of 650 m, which consist mainly of calcareous sediments was studied in detailed but third section, qelli section, with a thickness of about 450m which consist mainly of sandstone and evaporates...

Journal: :Chemosphere 2012
Stuart L Simpson Daniel Ward David Strom Dianne F Jolley

Acid-volatile sulfides (AVS) are an important metal-binding phase in sediments. For sediments that contain an excess of AVS over simultaneously extracted metal (SEM) concentrations, acute or chronic effects should not result from the metals Cd, Cu, Ni, Pb and Zn. While AVS phases may exist in surface sediments, the exposure to dissolved oxygen may oxidize the AVS and release metals to more bioa...

2017
Agnieszka Baran Marek Tarnawski Krzysztof Urbański Agnieszka Klimkowicz-Pawlas Iwona Spałek

The aims of the study were to investigate the concentration, sources and ecological risk of PAHs (polycyclic aromatic hydrocarbons) in bottom sediments collected from nine reservoirs located in south-eastern Poland. The concentration of ∑PAHs in sediments ranged from 150 to 33,900 μg kg-1. The total PAH concentration in the bottom sediments was arranged in the following order: Rybnik > Rzeszów ...

2014
Zucheng Wang Zhanfei Liu Kehui Xu Lawrence M Mayer Zulin Zhang Alexander S Kolker Wei Wu

BACKGROUND Coastal sediments in the northern Gulf of Mexico have a high potential of being contaminated by petroleum hydrocarbons, such as polycyclic aromatic hydrocarbons (PAHs), due to extensive petroleum exploration and transportation activities. In this study we evaluated the spatial distribution and contamination sources of PAHs, as well as the bioavailable fraction in the bulk PAH pool, i...

Journal: :Bioscience, biotechnology, and biochemistry 2002
Masaki Kozono Shinya Nomoto Hajime Mita Ryoshi Ishiwatari Akira Shimoyama

Tokyo Bay bottom sediments were analyzed for 2-ethyl-3-methylmaleimide, a degradation product of chlorophylls, which has been detected in ancient sediments. It was found in all sediments examined in concentrations of about 1 to 15 nmol/g- of dried sediment, and it was shown to be preserved for 100 years in the sediments. Its depth distribution agreed with that of the reported total organic carb...

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