نتایج جستجو برای: noncohesive sediments

تعداد نتایج: 28528  

2007
Ramananda Chakrabarti Asish R. Basu Amitabha Chakrabarti

Ancient sediments reflect the compositions of old eroded continental crustal material and preserve geochemical signatures of paleo-tectonic and volcanic events. Geochemical study of such sediments provides insight into tectonic events that shaped the face of the Earth. Nd isotopes are best suited for such studies because rare earth elements (REE), specifically Sm and Nd are not fractionated dur...

Journal: :Applied and environmental microbiology 2000
S C Nold J Zhou A H Devol J M Tiedje

The diversity of ammonia-oxidizing bacteria in aquatic sediments was studied by retrieving ammonia monooxygenase and methane monooxygenase gene sequences. Methanotrophs dominated freshwater sediments, while beta-proteobacterial ammonia oxidizers dominated marine sediments. These results suggest that gamma-proteobacteria such as Nitrosococcus oceani are minor members of marine sediment ammonia-o...

2016
Francis Hassard Ceri L. Gwyther Kata Farkas Anthony Andrews Vera Jones Brian Cox Howard Brett Davey L. Jones James E. McDonald Shelagh K. Malham

The long term survival of fecal indicator organisms (FIOs) and human pathogenic microorganisms in sediments is important from a water quality, human health and ecological perspective. Typically, both bacteria and viruses strongly associate with particulate matter present in freshwater, estuarine and marine environments. This association tends to be stronger in finer textured sediments and is st...

Journal: :Marine environmental research 2009
Alan J Kennedy Jeffery A Steevens Guilherme R Lotufo John D Farrar Mark R Reiss Roy K Kropp Jon Doi Todd S Bridges

Sediment toxicity tests are valuable tools for assessing the potential effects of contaminated sediments in dredged material evaluations because they inherently address complexity (e.g., unknown contaminants, mixtures, bioavailability). Although there is a need to understand the chronic and sublethal impacts of contaminants, it is common to conduct only short-term lethality tests in evaluations...

Journal: :Science 1979
J J Griffin E D Goldberg

Carbon particles extracted from sediments collected by box coring from southeastern Lake Michigan were compared with carbon particles extracted from oil, coal, and wood fly ash. Sediments deposited after 1900 contained coal, oil, and wood carbons; older sediments contained only wood carbon.

Kaloutaks are a geomorphological forms of arid and semi-arid regions around the world. These features are extensive and varied in Iran, resulting from the erosion of fluvial and lake sediments of the Quaternary. Kaloutaks are mostly extended over the Eastern and Southeastern Iran and have unique features. Meanwhile, the kaloutaks in the playa of Sistan Hamun are considerably extended.  The stud...

Journal: Pollution 2019

The present study was carried out to investigate the adsorption and leaching behavior of Cu2+, Zn2+ and Pb2+ by sediments collected from the western banks of three different sectors along River Nile at Aswan governorate, Egypt. The feasibility of sediments for the removal of Cu2+, Zn2+ and Pb2+ from aqueous solutions was tested under the effect of three conditions (pH, initial metal concentrati...

Journal: :international journal of environmental research 2010
c.s. ratheesh kumar m.m. joseph t.r. gireesh kumar k.r. renjith m.n. manju

heavy metals in the surface sediments of the two coastal ecosystems of cochin, southwest india were assessed. the study intends to evaluate the degree of anthropogenic influence on heavy metal concentration in the sediments of the mangrove and adjacent estuarine stations using enrichment factor and geoaccumulation index. the inverse relationship of cd and zn with texture in the mangrove sedimen...

Journal: :international journal of environmental research 2013
a.h. arias a. vazquez-botello g. diaz j.e. marcovecchio

the usage and production of polychlorinated biphenyls (pcbs) was banned in argentina in2002, approximately twenty to thirty years later than in other countries. a total of 29 sediment samples (upto 14 m deep) were analyzed for a mix of seven individual pcbs in a time series for over more than one year in twelve selected locations, including harbors, recreational docks and several industrialized...

Journal: :international journal of marine science and engineering 2012
a. biati h. nikoomaram a. r. karbassi

since heavy metals are considered as one of the major pollutants threatening, the main goal of this study was to bring out the concentrations of pb, zn and mn in the surface sediments off bushehr in the persian gulf. for this purpose, after collection of samples, the concentrations of the three metals in surface sediments were measured through the atomic absorption. the results were compared wi...

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