نتایج جستجو برای: sediment cores pollution
تعداد نتایج: 128525 فیلتر نتایج به سال:
background: this study aimed to evaluate the pollution levels of surface water with heavy metals including pb, cd and cr in gheshlagh river, western iran. methods: water and sediment were sampled in five monitoring stations with three replicates in time along the river. the concentration of cr, pb and cd in both water and sediment samples were measured with graphite furnace atomic absorption sp...
Water and sediment samples were collected from 20 location of the Buriganga river of Bangladesh during Summer and Winter 2009 to determine the spatial distribution, seasonal and temporal variation of different heavy metal contents. Sequential extraction procedure was employed in sediment samples for the geochemical partitioning of the metals. Total trace metal content in water and sediment samp...
Microbial communities present in marine sediments play a central role in nitrogen biogeochemistry at local to global scales. Along the oxidation-reduction gradients present in sediment profiles, multiple nitrogen cycling processes (such as nitrification, denitrification, nitrogen fixation, and anaerobic ammonium oxidation) are active and actively coupled to one another - yet the microbial commu...
The responses of major meiofaunal taxa and nematode species assemblage to the decaying leaf litter of the mangrove Kandelia candel were investigated through a field colonization experiment in subtropical Hong Kong. Sixty-four replicate azoic and organic-free sediment cores were treated with leaf litter additions of 0x, 0.5x, 1x and 2x natural sediment organic concentration, respectively, and re...
Sediment cores provide a valuable record of historical contamination, but so far, new analytical techniques such as high-resolution mass spectrometry (HRMS) have not yet been applied to extend target screening to the detection of unknown contaminants for this complex matrix. Here, a combination of target, suspect, and nontarget screening using liquid chromatography (LC)-HRMS/MS was performed on...
Radiocarbon dating and sedimentological studies of closely spaced cores indicate movement during the Holocene of sediments on the New Jersey continental slope and upper rise between Wilmington and Lindenkohl canyons. The uneven time-stratigraphic thickness of the late Quaternary sediment sections between cores and the nonuniform deposition rate at any given core site and among core sites show t...
A laboratory based microcosm study was undertaken to determine the persistence of the faecal indicator organism Escherichia coli in coastal recreational water and sediment under varying environmental conditions. Intact sediment cores were taken from three distinct coastal sites in the Adelaide metropolitan area and the overlying water was inoculated with known concentrations of E. coli. The con...
background: heavy metal pollution in the sediment of the yellow river draws wide attention in the recent years. the yellow river wetland nature reserve of zhengzhou is one of the major wetlands of the river and located at the beginning of the lower reach. in this article, we aimed to investigate the degree and the sources of the metal pollution in the reserve. methods: metals as cu, pb, cr, cd ...
Despite the important roles of shallow-water sediments in global biogeochemical cycling, the effects of ocean acidification on sedimentary processes have received relatively little attention. As high-latitude cold waters can absorb more CO2 and usually have a lower buffering capacity than warmer waters, acidification rates in these areas are faster than those in sub-tropical regions. The presen...
To assess the ca. 20-year polychlorinated biphenyl (PCB) contamination trends in Lake Hartwell, SC, sediment cores from the Twelve Mile Creek arm were collected in July 2004 at two sites (G30 and G33) first sampled in the mid-1980s. Congener-specific PCB data as a function of depth from the sediment-water interface for the 2004 sediment samples were compared to data obtained from 1987 and 1998 ...
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