نتایج جستجو برای: surface sediments

تعداد نتایج: 658804  

Journal: :Chemosphere 2006
Sue-Min Chang Ruey-An Doong

The concentration and fate of persistent organochlorine pesticides (OCPs) in estuarine surface sediments in Erh-jen and Lan-yang rivers, Taiwan were investigated using headspace solid-phase microextraction (HSSPME) method to evaluate the possible pollution potential and guideline for OCP concentrations in Taiwan. The HSSPME method exhibits a good analytical performance with low detection limits...

2014
Bo Gao Jin Lu Hong Hao Shuhua Yin Xiao Yu Qiwen Wang Ke Sun

To investigate the characteristics and potential sources of heavy metals pollution, surface sediments collected from Bohai Bay, North China, were analyzed for the selected metals (Cd, Cr, Cu, Ni, Pb, and Zn). The Geoaccumulation Index was used to assess the level of heavy metal pollution. Pb isotopic compositions in sediments were also measured to effectively identify the potential Pb sources. ...

2012
Isabela C. Torres Patrick W. Inglett Mark Brenner William F. Kenney Ramesh Reddy

Lake sediments contain archives of past environmental conditions in and around water bodies and stable isotope analyses (dC and dN) of sediment cores have been used to infer past environmental changes in aquatic ecosystems. In this study, we analyzed organic matter (OM), carbon (C), nitrogen (N), phosphorus (P), and dC and dN values in sediment cores from three subtropical lakes that span a bro...

2010
Hai Xu Bin Liu Feng Wu

The Rb/Sr ratios of lake sediments have been suggested as indicators of weathering intensity by increasing work. However, the geochemistry of Rb/Sr ratios of lake sediments is variable between different lakes. In this study, we investigated the spatial and temporal patterns of Rb/Sr ratios, as well as those of other major elements in surface sediments of Lake Qinghai. We find that the spatial p...

Journal: :Environmental pollution 2001
N F Tam L Ke X H Wang Y S Wong

The concentrations of total polycyclic aromatic hydrocarbons (sigmaPAHs) and 15 individual PAH compounds in 20 surface sediments collected from four mangrove swamps in Hong Kong were analysed. sigmaPAH concentrations ranged from 356 to 11,098 ng g(-1) dry weight with mean and median values of 1992 and 1,142 ng g(-1), respectively. These values were significantly higher than those of marine bott...

2000
J. B. Harris

Shallow shear wave reflection surveys using high frequency vibroseis techniques provides information about the Tertiary bedrock surface and Pleistocene sediments on the Fraser River delta, in B.C., Canada. Besides the clear advantage of shear wave profiling in this shallow gas environment, the added resolution potential and ability to measure the shear wave velocity field enhances the fusion of...

Journal: :Applied and environmental microbiology 1995
T Hoaki M Nishijima H Miyashita T Maruyama

Microbial communities in marine hydrothermal sediments (0 to 30 cm deep) in an inlet of Kodakara-Jima Island, Kagoshima, Japan, were studied with reference to environmental factors, especially the presence of amino acids. The study area was shallow, and the sea floor was covered with sand through which hot volcanic gas bubbled and geothermally heated water seeped out. The total bacterial densit...

2011
Meng Li Yi-Guo Hong Hui-Luo Cao Ji-Dong Gu

Anaerobic ammonium oxidizing (anammox) bacterial community structures were investigated in surface (1-2 cm) and lower (20-21 cm) layers of mangrove sediments at sites located immediately to the mangrove trees (S0), 10 m (S1) and 1000 m (S2) away from mangrove trees in a polluted area of the Pearl River Delta. At S0, both 16S rRNA and hydrazine oxidoreductase (HZO) encoding genes of anammox bact...

2014
Nicole M. Scott Matthias Hess Nick J. Bouskill Olivia U. Mason Janet K. Jansson Jack A. Gilbert

During hydrocarbon exposure, the composition and functional dynamics of marine microbial communities are altered, favoring bacteria that can utilize this rich carbon source. Initial exposure of high levels of hydrocarbons in aerobic surface sediments can enrich growth of heterotrophic microorganisms having hydrocarbon degradation capacity. As a result, there can be a localized reduction in oxyg...

رحیم‎پوربناب , حسین, عبدی, لیلا ,

In this study, brine and sediment samples from the Meighan basin located about 15 km northeast of Arak city were considered. Sediments samples were collected from boreholes and surface sediments of playa bed were studied for their mineralogical content by X-ray diffraction (XRD) technique and sedimentology.The results showed that the Playa sediments were consist of chemical (evaporate) and detr...

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