نتایج جستجو برای: noncohesive sediments

تعداد نتایج: 28528  

2015
Abriak Nor Edine

This work is undertaken to develop a methodology to enhance the management of dredged marine an the North of France. The main objective of this study is to determine the main characteristics of these sediments. In this order, physical, mineralogical and chemical properties of both types of sediments are measured. Moreover, their potential impacts on the environment are assessed throughout leach...

2000
R. F. Chen

Chlorophyll degradation products are preserved in marine sediments over timescales of thousands of years. The production of chlorophyll in the water column is related to biological productivity, so chlorophyll degradation products (chlorins) preserved in marine sediments can be used as indicators of paleoproductivity. A new, rapid, nondestructive method of determining chlorin concentrations in ...

2017

Sediments tell a tsunami story Trying to understand where major earthquakes and tsunamis might occur requires analysis of the sediments pouring into a subduction zone. Thick sediments were expected to limit earthquake and tsunami size in the Sumatran megathrust event in 2004, but the magnitude 9.2 earthquake defied expectations. Hüpers et al. analyzed sediments recovered from the Sumatran megat...

Background: Land and water pollution by heavy metals is a universal issue. Although the pollution affects all countries, but its range and severity vary hugely. The pollution of the marine environment by heavy metals is a worldwide problem. Marine sediments can be sensitive indicators for monitoring contaminants in aquatic environments. Methods: The concentration of 10 elements (As, Cd, Cr, Cu...

ژورنال: علوم آب و خاک 2023

The relationship between the concentration of heavy metals and physicochemical factors was studied in the fine-grained sediments of the tidal section of the Mehran delta where mangrove trees have grown. Surface sediments of the tidal zone of the Mehran delta were sampled. The grain size distribution, calcium carbonate, organic matter contents, pH/Eh, and heavy metals concentration were determin...

2017
Sylvain Richoz Andre Baldermann Andreas Frauwallner Mathias Harzhauser Gudrun Daxner-Höck Dietmar Klammer Werner E Piller

The Valley of Lakes is approximately a 500-km elongate depression in Central Mongolia, where Eocene to Miocene continental sediments are long known for their outstanding fossil richness. The palaeontological record of this region is an exceptional witness for the evolution of mammalian communities during the Cenozoic global cooling and regional aridification. In order to precisely elucidate the...

Journal: :Ecotoxicology and environmental safety 2009
John M Besser William G Brumbaugh Ann L Allert Barry C Poulton Christopher J Schmitt Christopher G Ingersoll

We studied the toxicity of sediments downstream of lead-zinc mining areas in southeast Missouri, using chronic sediment toxicity tests with the amphipod, Hyalella azteca, and pore-water toxicity tests with the daphnid, Ceriodaphnia dubia. Tests conducted in 2002 documented reduced survival of amphipods in stream sediments collected near mining areas and reduced survival and reproduction of daph...

2004
Robert P. Eganhouse

In recent years, the Coastal Water Research Project has conducted surveys of the distribution of certain trace substances in sediments around the major municipal wastewater outfalls off southern California. Because of high levels of heavy metals found in sediments near Los Angeles County Sanitation Districts outfall system off Whites Point in 1970, detailed surveys of the Palos Verdes shelf wer...

2017
Adrienne Hoarfrost Rachel Snider Carol Arnosti

Extracellular enzymatic activities initiate microbially-driven heterotrophic carbon cycling in subsurface sediments. While measurement of hydrolytic activities in sediments is fundamental to our understanding of carbon cycling, these measurements are often technically difficult due to sorption of organic substrates to the sediment matrix. Most methods that measure hydrolysis of organic substrat...

Journal: :Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering 2006
X Zhang M Lulla

This study evaluated the bacterial distribution and the survivability of bacteria associated with different particle size ranges in the sump water and sediments within two structural Best Management Practices (BMPs), called Vortechs, installed at two different sites in Providence, Rhode Island. Ten rain storms were sampled in year 2004. Five pathogenic indicator bacteria, E. coli, enterococci, ...

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